8th International SymposiumonLaser Precision
Microfabrication
April 24 - 28, 2007, University of Vienna, Austria
Main Building, Dr.-Karl-Lueger-Ring 1, A-1010 Vienna

Program&
Abstracts
Local Chairmen
Wolfgang Kautek (University of Vienna)
Dieter Schuöcker (Vienna University of Technology)

Editors
Wolfgang Kautek, Günter Trettenhahn
Claudia Weber, Christian Zafiu

Homepage
http://cms.univie.ac.at/lpm2007/

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24-28 April 2007, University of Vienna, Vienna, Austria

Foreword
Laser micro-fabrication has become a fast growing field of
science and technology. This trend was triggered by relying
on a highly directional light beam, easily focused into a close
to diffraction-limited spot size. With the development of pulsed
lasers with progressively shorter pulse durations, the field oflaser material processing emerged. The thoroughunderstanding of the physical and chemical mechanisms oflight–matter interactions and ablation at high irradiancebecame the prerequisite of a widening number of scientificand industrial applications.
Prof. Dr. Wolfgang Kautek

Particularly ultrashort (subpicosecond) lasers have expanded Local Chair, LPM 2007
the field of material processing into the real three-dimensional(3D) domain. Ablation can be used to fabricate 3D microstructures on the one hand,
however, highly nonlinear light–matter interaction made possible by the ultimate lightintensities achieved by ultrashort pulses allows real 3D structuring of materials fromthe "inside" (bulk). Thus, even nanomicro-structuring is provided in the irradiance
range of more than 1014 Wcm–2 Combined with modern mechanical microtechnological technologies, this makes the ultrashort pulse approach attractive interms of its “green”, environmentally friendly, high precision and effective single-stepprocedure.
The "8th International Symposium on Laser Precision Microfabrication", LPM 2007,
provides a forum for discussion on the fundamental aspects of laser/materialinteraction, the state of the art of laser materials processing and in the germination of
next-generation ideas that arises from collaborating scientists, end users and laser
manufacturers. LPM 2007 is based on a series of yearly held symposia in Omiya /Japan (2000), Singapore (2001), Osaka / Japan (2002), Munich / Germany(2003),
Nara / Japan (2004), Williamsburg / USA (2005), and Kyoto / Japan (2006).

A major special session is being jointly organized together with the "3rd European
Conference on Applications of Femtosecond Lasers in Materials Science", FemtoMat
2007. This looks back on a recent tradition of two events in Visegrád / Hungary(2002) and Bad Kleinkirchheim / Austria (2004).
The LPM 2007 is organized as a four-day event with a plenary session providing athorough introduction into up-to-date laser processing and laser chemistry followedby micro- and nano-fabrication. There are two parallel oral sessions which will beinterrupted around noon by so-called Poster Lunch Sessions characterized by poster
presentations and Viennese buffet catering. A permanent table-top exhibitionneighbouring the poster locations is allowing steady insight into recent productprogrammes and communication with modern laser and optics companies.
World authorities have been involved in the scientific planning of each session. My
local co-chair, Dieter Schuöcker, and I would like to thank particularly them for their

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24-28 April 2007, University of Vienna, Vienna, Austria

invaluable suggestions and support in the preparation of the program and theinvitation of top-level invited speakers. We would like to acknowledge the steady help
by the JLPS secretary Ms. Hiromi Teraoka, the general LPM chair Isamu Miyamoto,and the co-chairs, Koji Sugioka, Friedrich H. Dausinger, Henry Helvajian, Kazuyoshi
Itoh, and Seiji Katayama.
There has been a broad interest and sponsoring support by Austrian publicauthorities both on the federal and the local city community level, by internationalorganizations, but also by international and Austrian companies. Their contribution
has been crucial for the realization of LPM 2007.
Last but not least we have to express our thanks to our local organizing committee,
Magdalena Forster, Gerhard Humenberger, Günter Trettenhahn, Claudia Weber, andChristian Zafiu, without their help the preparation of LPM 2007 would not have beenpossible.
We hope that LPM 2007 and Austrian hospitality will serve as a platform of intensive
scientific and technological communication which may yield progress in laser
nanomicro fabrication technologies world-wide, and may eventually also lead tofriendships between scientists.
Vienna, April 2007
Wolfgang Kautek (University of Vienna)
Dieter Schuöcker (Vienna University of Technology)

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

S
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Austrian Chemical Society
Gesellschaft Österreichischer Chemiker (GÖCH)
Nibelungengasse 11/6, A-1010 Vienna,
Email: office@goech.at; http://www.goech.at/

University of Vienna
Dr.-Karl-Lueger-Ring 1, A-1010 Vienna
http://www.univie.ac.at

Vienna University of Technology
Karlsplatz 131040 Wien
http://www.tuwien.ac.at

Austrian Laser Association
Arbeitsgemeinschaft für Lasertechnik (ARGELAS)
Arsenal, Obj.207, Franz-Grill Str. 1, A-1030 Wien
E-Mail: sekretariat+e345@tuwien.ac.at; Internet: http://www.argelas.org

European Office of Aerospace Research & Development (EOARD)EDISON House, London, UK

Bundesministerium für Wissenschaft und ForschungMinoritenplatz 5, A-1014 Wien
Internet: http://www.bmwf.gv.at

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The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Stadt Wien
Kulturabteilung (Magistratsabteilung 7)
Friedrich-Schmidtplatz 5, A-1080 Wien (Rathaus)
E-Mail: post@m07.magwien.gv.at; http://www.wien.gv.at/kultur/abteilung/

Vienna Convention Bureau
Untere Augartenstrasse 38 / Top 5, A-1020 Wien
E-Mail: convention@vienna.info; http://www1.vienna.convention.at

Erwin Schrödinger Society for Nanosciences
Schmiedlstrasse 6, A-8042 Graz
E-Mail: ruth.prassl@oeaw.ac.at; http://www.ibr.oeaw.ac.at/esgnano/en/index.html

Austrian Society for Microsystem Technology (OGMS)
Floragasse 7/2, A-1040 Wien
E-Mail: office@ogms.at; http://www.ogms.at/default_e.htm

High Q Laser Production GmbH
Kaiser-Franz-Josef-Str. 61, A-6845 Hohenems
E-Mail: sales@highqlaser.at; http://www.highqlaser.at

Time-Bandwidth Products AG (TBP)
Technoparkstrasse 1
CH-8005 Zürich
E-mail: info@tbwp.com; http://www.tbwp.com/

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The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Coherent Inc.
5100 Patrick Henry Drive
Santa Clara, CA 95054 USA
http://www.coherent.com/

3-D Micromac AG
Annaberger Straße 240
D-09125, Chemnitz
http://www.3d-micromac.com/

FEMTOLASERS Produktions GmbH
Fernkorngasse 10
A - 1100 Vienna
E-mail: info@femtolasers.com; http://www.femtolasers.com

EROTHITAN Titanium Implants SA
Auenstraße 3 - 5, D-98529 Suhl
E-Mail: info@erothitan.com; http://www.erothitan.com/

Botanical Garden of the University of Vienna(Hortus Botanicus Vindobonensis - HBV)
Rennweg 14, A-1030 Vienna,
email: botanik@univie.ac.at; http://www.botanik.univie.ac.at/hbv/english/hbv.htm

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General Chair: Isamu Miyamoto (Osaka Univ., Japan)
Co-Chairs: Wolfgang Kautek (Univ. of Vienna, Austria); Dieter Schuoecker (Vienna
Univ. of Technology, Austria); Koji Sugioka (RIKEN-The Institute of Physical andChemical Research, Japan); Seiji Katayama (Osaka Univ., Japan); Henry Helvajian(The Aerospace Corporation, USA); Friedrich H. Dausinger (Univ. of Stuttgart, Institut
fur Strahlwerkzeuge, IFSW, Germany); Kazuyoshi Itoh (Osaka Univ., Japan)
Members: Alan Arai (IMRA America, Inc., USA); Zhaogu Cheng (Shanghai Instituteof Optics and Fine Mechanics, CAS, China); Corey M. Dunsky (Coherent Inc., USA);
Alexander Glass (AFOSR/AOARD, USA); Burkhard Fechner (Lambda Physik AG,
Germany); Kenshi Fukumitsu (Hamamatsu Photonics K.K., Japan); Willem Hoving(Philips Electronics Nederland B. V. – VFT, Netherlands); Takashi Ishide (Mitsubishi
Heavy Industry, Japan); Shinichi Ishizaka (Japan Steel Works America, Inc., USA);
Teruyoshi Kadoya (TRUMPF Corporation, Japan); Kazuo Kamada (Matsushita
Electric Works, Ltd., Japan); Hidehiko Karasaki (Matsushita Welding Systems Co.,
Ltd., Japan); Vitali Konov (GPI- General Physics Institute, Russia); Ernest W. Kreutz(Lahrsturl fur Lasertechnik, RWTH-Aachen, Germany); Max Lederer (High Q Laser
Production GmbH, Austria); Cheon Lee (Inha Univ., South Korea); Hiroshi Masuhara(Osaka Univ., Japan); Hiroaki Misawa (Hokkaido Univ., Japan); Takashi Miyoshi(Osaka Univ., Japan); Sumio Nakahara (Kansai Univ., Japan); Klaus Nowitzki (EOSEuropean Optical Society, Germany); Tatsuo Okada (Kyushu Univ., Japan); Andreas
Ostendorf (Laser Zentrum Hannover e.V., Germany); Tino Petsch (3D-Micromac AG,
Germany); Reinhart Poprawe (Lehrstuhl fur Lasertechnik, Germany); Hitoshi Sekita(Cyber Laser, Japan); Andreas Stingl (FEMTOLASERS Produktions GmbH, Austria);
Radvan Stoian (Universite Jean Monnet, France); Shozui Takeno (Mitsubishi Electric
Corporation, Japan); Osamu Wakabayashi (Gigaphoton, Japan); Yuka Yamada(Matsushita Electric Industrial Co., Ltd., Japan)

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24-28 April 2007, University of Vienna, Vienna, Austria

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Chairperson: Wolfgang Kautek (Univ. of Vienna, Austria)
Members: Craig B. Arnold (Princeton Univ., USA); Eric Audouard (Universite Jean
Monnet, France); Sung-Hak Cho (Korea Institute of Machinery & Materials, South
Korea); Jan J. Dubowski (Universite de Sherbrooke, Canada); Gerd Esser (Diehl
Stiftung & Co. KG, Germany); Eric Fogarassy (Universite Louis Pasteur deStrasbourg, France); Costas Fotakis (I.E.S.L.-Institute of Electronic Structure andLaser, F.O.R.T.H.-Foundation for Research and Technology-Hellas, Greece); Arnold
Gillner (Fraunhofer-Institute for Laser Technology, Germany); Costas P.
Grigoropoulos (University of California Berkeley, USA); Bo Gu (GSI Group, USA);
Dennis R. Hall (Heriot-Watt Univ., UK); Peter R. Herman (Univ. of Toronto, Canada);
Ingolf V. Hertel (Max-Born Institute for Nonlinear Optics and Short-Pulse
Spectroscopy, Germany); Andrew S. Holmes (Imperial College, UK); Minghui Hong
(Data Storage Institute, Singapore); Juergen Ihlemann (Laser Laboratory Goettingen,Germany); Yoshiro Ito (Nagaoka Univ. of Technology, Japan); Takahisa Jitsuno(Osaka Univ., Japan); Sylvain Lazare (Universite de Bordeaux 1, France); Thomas
Lippert (Paul Scherrer Institut, Switzerland); Yong-Feng Lu (Univ. of Nebraska, USA);
Shoji Maruo (Yokohama National Univ., Japan); Simeon Metev (BIAS-Bremen
Institute of Applied Beam Technology, Germany); Michel Meunier (Ecole
Polytechnique de Montreal, Canada); Yoshiki Nakata (Osaka Univ., Japan); Hiroyuki
Niino (AIST-National Institute of Advanced Science and Technology, Japan); Jyunji
Nishii (AIST-National Institute of Advanced Science and Technology, Kansai, Japan);Satoru Nishio (Ritsumeikan Univ., Japan); Etsuji Ohmura (Osaka Univ., Japan);
Masayuki Okoshi (National Defence Academy, japan); Toshihiko Ooie (AIST-National
Institute of Advanced Science and Technology, Japan); Alberto Pique (Naval
Research Laboratory, USA); Juergen Reif (Brandenburg Univ. of Technology,
Cottbus, Germany); Dieter Schuoecker (Vienna Univ. of Technology, Austria); Tamás
Szörényi (Hungarian Academy of Sciences, Hungary); Javier Solis (Instituto de
Optica, CSIC, Spain); Koji Sugioka (RIKEN-The Institute of Physical and Chemical
Research, Japan); Vadim Veiko (St. Petersburg State Univ. of Information
Technologies, Russia); Kunihiko Washio (Paradigm Laser Research Ltd., Japan,
Xianfan Xu (Purdue Univ., USA)

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

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LPM 2007

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The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Lecture Rooms
Poster, Exhibition, Coffee Break, Lunch
Conference Desk

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The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

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Table-Top Exhibition
From Tuesday afternoon, April 24, until Friday evening, April 27.
Kleiner Festsaal

Poster Lunch Sessions
From Wednesday, April 25, until Friday, April 27
Kleiner Festsaal and Reception Hall
Complimentary Viennese Buffet served (Sponsors indicated)

Coffee Breaks
Everyday
Kleiner Festsaal and Reception Hall

Femtolasers Company Reception
Thursday, April 26, 19:00h
Bus service to Femtolasers provided. Dinner Buffet offered.

LPM Conference Dinner
Friday, April 27, 19:00h
Bus service provided.
Grinzing

LPM Committee Meeting(Invited members)
Wednesday, April 25, 19:00h
Hotel Regina

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24-28 April 2007, University of Vienna, Vienna, Austria

ONLINE LPM2007 PROCEEDINGS
Submission Due Date (on-site): April 24, 2007
CD-R media with both PDF and Word files and one hardcopy should be delivered on
April 24, 2007 on-site at the conference office desk. The LPM2007 Proceedings will
be published online after the event. Full Registration will include the access to theonline LPM2007 Proceeding.
Manuscript Guidelines and Copyright Transfer Form:
http://cms.univie.ac.at/lpm2007/

JLMNJOURNAL OF LASERMICRO/NANOENGINEERINGThe authors have the opportunity to publish their proceedings manuscripts in the
Journal of Laser Micro/Nanoengineering. The manuscripts will be peer-reviewed.
Authors who wish to submit their manuscripts to this Journal should check the box in
the Copyright Transfer Form. Then the submitted manuscript will be automaticallypassed to the review process. The authors may suggest reviewers. If the authors
provide reviewers, please attach the list of at least three names, with full information
on postal and e-mail addresses, telephone number, and fax number, to the CopyrightTransfer Form.
Download Manuscript Guidelines for JLMN, Publication Policy of JLMN, and JLMN
Website: http://www.jlps.gr.jp/jlmn/

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

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Tuesday, April 24
11:00-15:00
Registration Time

15:00-15:30
Opening Remarks
15:30-16:30
Plenary Talk
Bäuerle (Inv.)
Laser processing and chemistry: Fundamentals andapplications in micro- and nano-fabrication
Coffee Break 16:30-17:00
Session 4-1
17:00 We 4-01
Forsman (Inv.)
Advanced double pulse format for increasing the speed andquality of high aspect ratio laser micromachining
17:30 We 4-02
VeikoNonlinear Nd:YAG laser-induced optical blooming of glassceramics
17:50 We 4-03
ItoFabrication of an OLED display using an ultra-short fiber
laser
18:10 We 4-04
Haglund
Electronic properties of thin polymer films deposited byresonant infrared laser ablation

18:30-20:00
3D-Micromac Welcome Reception

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24-28 April 2007, University of Vienna, Vienna, Austria

Wednesday, April 25
Großer Festsaal
Session S1-1
9:00 We S1-01
Nakata (Inv.)
Nano-sized and periodic structuresgenerated by interfering femtosecond
laser processing
9:30 We S1-02
ReifControl parameters for self-organizednanostructure formation upon
femtosecond laser ablation

Elise Richter Saal

09:30 We S3-02
Bekesi
Grating interferometers for efficient generationof large area grating structures via laser
ablation

9:50 We S1-03
Zhao
Periodic structuring of metals by
femtosecond laser pulses

9:50 We S3-03
GanserFabrication of Nd:Gd3Ga5O12 planar
waveguide laser by pulsed laser radiation

Session S3-1
9:00 We S3-01
John (Inv.)
Optical Lithography of Photonic Band Gap
Materials

10:10 We S1-04
10:10 We S3-04
Sun
MaertenStanding electron plasma wave
Trouble Shooting and Optimization of Laser
mechanism of void array formation
Beam Parameters for Precision Microinside glass irradiated by femtosecond
Fabrication by Beam Analysis
laser pulses
Coffee Break 10:30-11:00
Session S1-2
11:00 We S1-05
Boneberg (Inv.)
Focussing fs-pulses with optical nearfields
11:30 We S1-06
StoianEnergy coupling and material removalfrom metallic surfaces irradiated bytemporally-shaped and ultrashort laser
pulsesSession S3-2
11:00 We S3-05
Katayama
In-Process Monitoring and Adaptive Control
during Micro Welding with CW Fiber Laser

11:50 We S1-07
Izawa
Ultra low energy crystallization process
for Si by femtosecond laser irradiation

11:40 We S3-07
WeilerAblative laser micro processing with short andultrashort pulses

11:20 We S3-06
BrockmannLatest Disk Laser for Industrial Applications

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Wednesday, April 25
Großer Festsaal

Elise Richter Saal

12:10 We S1-08
12:00 We S3-08
Horn
Hoenninger
Investigations onmelting and welding ofMillijoule high-repetition rate femtosecond laser
glass by ultra-short pulsed laser
amplifierradiation
12:30-14:30
Time Bandwidth Products AG
Poster Lunch Session
Session S2-1
14:30 We S2-01
Rode (Inv.)
3D write-read-erase memory bits byfemtosecond laser pulses inphotorefractive LiNbO3 crystal

Session 6-1
14:30 We 6-01
HowardMechanisms of water assist for overcoming
the self-limiting effects of high aspect ratio
machining of silicon and for minimisingparticulate redeposit

15:00 We S2-02
M. Hong
Multi-lens array fabrication and its
applications in laser precision engineering

14:50 We 6-02
Zhigang
The Hydrodynamic theory and Simulation of
Liquid Phase for Laser shock Process

15:20 We S2-03
MisawaThree-Dimensional Femtosecond Laser
Microfabrication

15:10 We 6-03
Komatsu
Self-organized growth of sp3-bonded 5H-BN
electron-emitter micro cones prepared byplasma-assisted laser chemical vapor
deposition: experiments and modeling

15:40 We S2-04
Neumeister
3-D micro fabrication of mechanicalsystems using laser based stereo
lithography

15:30 We 6-04
BoehmeLaser-induced writing of submicron surface
relief gratings in fused silica on-the-fly

16:00 We S2-05
Passinger
Two-Photon Polymerization System for
Research and Industrial Applications
Coffee Break 16:30-17:00

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Wednesday, April 25
Großer Festsaal

Elise Richter Saal

Session S2-2
17:00 We S2-06
LeHarzic (Inv.)
Nanostructuring with Nanojoule
Femtosecond Laser Pulses

Session 11-1
17:00 We 11-01
Delmdahl
VUV laser technology for nanostructuring

17:30 We S2-07
Gonzalo
Optical and vibrational properties of selforganized silver nanocolumns

17:20 We 11-02
Baek
Organic layer direct patterning using a DUVexcimer laser

17:50 We S2-08
Miyamoto
Characteristics of internal melting ofglass for fusion welding using ps laser
pulses with average power up to 8W

17:40 We 11-03
CefalasDynamics and VUV laser processing offunctional polymeric surfaces

18:10 We S2-09
Zh. Wang
Femtosecond laser direct fabrication of
3D microoptical components buried
inside of photosensitive glass

19:00

LPM Committee Meeting

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24-28 April 2007, University of Vienna, Vienna, Austria

Thursday, April 26
Großer Festsaal

Elise Richter Saal

Session S1-3
9:00 Th S1-09
M. Schmidt (Inv.)
Non-thermal micro adjustment using
ultrashort laser pulses

Session 4-2
9:00 Th 4-05
Kim (Inv.)
A Experimental Study on Raising the Efficiencyof Production for Industrial SFF system

9:30 Th S1-10
MiyazakiNanostructuring with femtosecond laser
pulses on patterned DLC surface

09:30 Th 4-06
FukudaDevelopment of dry-etching system with Qswitched DPSS lasers for flat panel display

9:50 Th S1-11
Mizoshiri
Silica-based nonplanar structuresfabricated by femtosecond laser
lithography and plasma etching

9:50 Th 4-07
Molpeceres
UV laser microprocessing of photovoltaic
devices based on thin film a-Si:H

10:10 Th S1-12
Ko
Lithography-free, high resolution
polymer transistors by conductive
polymer laser ablation

10:10 Th 4-08
ZoppelSelective Laser Ablation of Photoresists for
MEMS Devices

Coffee Break 10:30-11:00
Session S1-4
11:00 Th S1-13
Papazoglou (Inv.)
Micro-filamentation induced permanent
structural modifications in fused silica
with intense sub-picosecond ultraviolet
laser pulses
11:30 Th S1-14
BaumertTailored femtosecond pulses fornanoscale laser processing of wide band
gap materials
11:50 Th S1-15
Solis
Structural transformation dynamics
below and above the ablation thresholdin fused silica upon single pulse
femtosecond laser irradiation

Session 4-3
11:00 Th 4-09
ArnoldRapidly tunable Bessel beam and patterngeneration for laser microprocessing

11:20 Th 4-10
GaspardLaser induced foaming and chemical
modifications of gelatine films
11:40 Th 4-11
Zhou
Fabrication of Surface-enhanced Raman
Scattering Substrate on Ag-doped Silicate
Glass Using Femtosecond Laser

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Thursday, April 26
Großer Festsaal
12:10 Th S1-16
MauclairDynamic correction of opticalaberrations during ultrafast laser
photoinscription of waveguides in bulk
transparent materials

Elise Richter Saal
12:00 Th 4-12
Pique
Laser Fabricated Microelectronic Circuits on
Flexible Substrates

12:30-14:30
Hi-Q-Laser
Poster Lunch Session
Session S2-3
14:30 Tu S2-10
Cheng (Inv.)
Integration of multifunctions in glasses
using 3D femtosecond laser
microfabrication
15:00 Tu S2-11
Anderson
Femtosecond-laser induced negativerefractive index shift in thin film
Ge0.23Sb0.07S0.70 chalcogenide glass

Session 5-1
14:30 Tu 5-01
Meunier«Green» processing of stable and ultra-purenanoparticles using femtosecond laser-induced
supercontinuum generation in water
14:50 Tu 5-02
Hahn
Influences on nanoparticle production during
pulsed laser ablation

15:20 Th S2-12
Nishiyama
Microfabrication of nonplanar surface
structures by femtosecond laser
lithography

15:10 Tu 5-03
Makimura
Silica Nanomachining Using Laser Plasma Soft
X-rays

15:40 Th S2-13
Nakamura
Femtosecond Laser Direct Writing of
Optical Waveguides in Silicone Film

15:30 Tu 5-04
Kobe
Growth of bi-phase crystalline/amorphous SmFe-Ta-N magnetic nano-droplets fabricated by
PLD

16:00 Th S2-14
Noh
Fabrication of a rainbow color logo
(diffraction grating) using the picosecond
laser

15:50 Tu 5-05
Guo
Extensive laser nanopatterning by microparticle lens arrays

Coffee Break 16:30-17:00

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Thursday, April 26
Großer Festsaal
Session S2-4
17:00 Th S2-15
Perrie (Inv.)NUV and NIR Femtosecond Laser
Modification of PMMA

Elise Richter Saal
Session 9-2
17:00 Th 9-06
DickmannLaser micro-perforation “on-the-fly“ as an
essential step of a novel process combination
for micro-sieve production

17:30 Th S2-16
V. Schmidt (Inv.)
Two-photon 3D lithography: A versatilefabrication method for complex 3D
shapes and optical interconnects within
the scope of innovative industrial
applications

17:20 Th 9-07
Michalowski
Melt Dynamics and Burr Formation during
Drilling with Ultrashort Pulses

18:00 Th S2-17
OhmuraInternal Modification of Ultra Thin Silicon
Wafer by Permeable Pulse Laser

17:40 Th 9-08
Naeem
Laser percussion drilling of aerospacematerials with a 20KW peak power fiberdelivered pulsed ND: YAG laser

18:20 Th S2-18
TomitaTEM observation of structural changes
under 4H-SiC single crystal surface
irradiated by femtosecond laser pulses

18:00 Th 9-09
Fortunato
3D modelling of LASER hardening andtempering of hypo-eutectoid steels

19:00

Femtolasers Company Reception

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Friday, April 27
Großer Festsaal
Session S1-5
9:00 Fr S1-17
Obara (Inv.)
Overview of laser micro/nanoprocessing
mediated with near field - the state of theart and future perspective
9:30 Fr S1-18
Audouard
Ultrafast laser processing of metals:
New tools and new results
9:50 Fr S1-19
Hoeche (Inv.)
Pulsed Laser Deposition using
Femtosecond Laser Radiation andPlasma Filtering

Elise Richter Saal
Session 8-1
9:00 Fr 8-01
Bellec (Inv.)
Femtosecond irradiation of a photosensitive
zinc phosphate glass containing silver
9:30 Fr 8-02
LippertLaser-Induced Forward Transfer (LIFT) of
Sensitive Materials Using a Photolabile
Dynamic Release Layer
9:50 Fr 8-03
GlushkovLaser photoionization and photodissociation
method and technologies for cleaning thesemiconductor materials and preparing thefilms of pure composition at atomic level
10:10 Fr 8-04
Ueta
Micro-Marking Using Violet Laser Diode with
Dyestuff and Pigments on Plastic Surfaces

Coffee Break 10:30-11:00
Session 7-1
11:00 Fr 7-01
Wintner (Inv.)
Ultra-Short Pulse Laser Ablation of
Biological Hard Tissue andBiocompatibles

Session S3-3
11:00 Fr S3-09
Nolte (Inv.)
Fiber lasers and amplifiers: Novel avenues toreal world applications of ultrashort lasers

11:30 Fr 7-02
Ooie
Laser-controlled pico-injector for nanobiodevices

11:30 Fr S3-10
Mai
Fundamental and Beam Propagation Behaviorof a Microjet® and Recent Applications using
Laser MicroJet Technology

11:50 Fr 7-03
BaerschUltrafast-laser-processed zirconia andits adhesion to dental cement

11:50 Fr S3-11
Tu
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Friday, April 27
Großer Festsaal

Elise Richter Saal

12:10 Fr 7-04
YousifInvestigation on Laser Dental Implants
Decontamenation
12:30-14:30
Poster Lunch Session
Session 7-2
14:30 Fr 7-05
Stoiber (Inv.)
Application of Femtosecond Lasers in
Ophthalmology

Session 9-1
14:30 Fr 9-01
Arai
Micromachining with a High Repetition Rate
Femtosecond
Fiber Laser

15:00 Fr 7-06
CholletUV excimer laser ablation of RGD
peptide grafted onto PET: Impact on cellattachment

14:50 Fr 9-02
OkamotoFine Micro-welding of Thin Stainless Steel
Sheet by High Speed Laser Scanning

15:20 Fr 7-07
FarsariSurface functionalization of 2D and 3D
structures using biomolecules

15:10 Fr 9-03
Kraus
Microdrilling in steel with frequency-doubled
ultrashort pulsed laser radiation

15:40 Fr 7-08
15:30 Fr 9-04
Strassl
Demir
Scanning of Ultra-Short Laser Pulses in Precision drilling of Ti6Al4V titanium alloy using
Dental Applications
pulsed Nd:YAG laser
16:00 Fr 7-09
Miyashita
Autofluorescence of electrophoresis chipgrooved by excimer laser

15:50 Fr 9-05
Ashkenasi
Comparing DPSSL Micro Drilling and Cutting
Applications at Different Wavelengths

Coffee Break 16:30-17:00

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24-28 April 2007, University of Vienna, Vienna, Austria

Friday, April 27
Großer Festsaal
Session 7-3
17:00 Fr 7-10
StampflBiofunctional Photopolymers for microstereolithography
17:20 Fr 7-11
Serra
Laser-induced forward transfer of liquids
for miniaturized biosensors preparation

Elise Richter Saal
Session 10-1
17:00 Fr 10-01
Newaz (Inv.)
Miniaturized Samples for Bond Strength andHermetic Sealing Evaluation for Transmission
Laser Joints
17:30 Fr 10-02
Sari
Laser Transmission Bonding and Welding ofSilicon, Glass and other Brittle-Rigid Materials
for Microsystems

17:40 Fr 7-12
HanadaBio-microchips fabricated in transparent
materials by femtosecond laser

17:50 Fr 10-03
MoalemLaser micro welding in silicon solar module
manufacturing

18:00 Fr 7-13
Guillermot
Infra-red (1064 nm) laser printing of
biological elements: preliminary results

18:10 Fr 10-04
Richter
Pulsed laser beam welding with filler wire

18:30-19:00
Closing Remarks
19:00

LPM Conference Dinner

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S
Seessssiio
onnssSpecial Session 1 (LPM-S-1)
Joint session with the "3rd European Conference on Applications of Femtosecond
Lasers in Materials Science" - FemtoMat 2007:
Applications of Femtosecond Lasers in Materials Science(Fundamentals, new processes, pulse shaping, etc.)
Session Organizers:
Eric Audouard (Université Jean Monnet, France), Ingolf Hertel (Max Born Institut, Germany), Xavier
Solis (Consejo Superior de Investigaciones Científicas - CSIC, Spain), Xianfan Xu (Purdue University,
USA)

Special Session 2 (LPM-S-2): 3D Micro- and Nanomachining(Ultrafast Laser processing, buried optical circuits, photonic bandgap materials etc.)
Session Organizers:
Boris Chichov (Laser Zentrum Hannover, Germany), Minghui Hong (DSI-Data Storage Institute,Singapore), Alberto Piqué (Naval Research Laboratory, USA), Yoshiro Ito (Nagaoka University ofTechnology, Japan)

Special Session 3 (LPM-S-3): Advanced Laser Systems and Optics(New Laser concepts and beam delivery systems, etc.)
Session Organizers:
Eric Fogarassy (Ecole nationale supérieure de physique de Strasbourg, France), Tino Petsch (3DMicromac AG, Germany), Andreas Stingl (Femtolasers Produktions GmbH, Austria)

Session 4 (LPM-4): Micromachining and Processing
Session 5 (LPM-5): Nanotechnology and Nanomaterials
Session 6 (LPM-6): Laser Hybrid and Media-Assisted Processes
Session 7 (LPM-7): Biomedical and Analytical Applications
Session 8 (LPM-8): Photochemistry
Session 9 (LPM-9): Micro-Drilling and Cutting
Session 10 (LPM-10): Micro-Welding and Bonding
Session 11 (LPM-11): Deep UV Laser Application

The 8th International Symposium on Laser Precision Microfabrication
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24-28 April 2007, University of Vienna, Vienna, Austria

Plenary Lecture

Tu Plenary
Talk
InvitedLaser processing and chemistry:
Fundamentals and applications in micro- and nano-fabrication
Dieter Bäuerle1
1Institut für Angewandte Physik, Johannes-Kepler-Universität Linz

Micro- and nanopatterning of various substrate materials by means of laser-direct writing andprojection [1-3], by near-field optical techniques (SNOM), and by 2D lattices of microlenses[4] will be presented. The possibility of focused anomalous transmission through metalcoated microspheres with subwavelength apertures is discussed as well [5,6].
[1] D. Bäuerle: Laser Processing and Chemistry, 3rd ed. (Springer, Berlin, Heidelberg, 2000)[2] S. Gigan et al.: Nature 444, 67 (2006)[3] H.R. Böhm et al.: Appl. Phys. Lett. 89, 223101 (2006)[4] D. Brodoceanu et al.: Appl. Phys. A 86, 313 (2007)[5] L. Landström et al.: Appl. Phys. A 83, 271 (2006)[6] G. Langer et al.: Appl. Phys. Lett. 89, 261104 (2006)

The 8th International Symposium on Laser Precision Microfabrication
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The 8th International Symposium on Laser Precision Microfabrication

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24-28 April 2007, University of Vienna, Vienna, Austria

Special Session 1 (LPM-S-1)
Joint session with the "3rd European Conference on
Applications of Femtosecond Lasers in Materials Science" FemtoMat 2007:

Applications of Femtosecond Lasers inMaterials Science(Fundamentals, new processes, pulse shaping, etc.)

Session Organizers:
Eric Audouard (Université Jean Monnet, France), Ingolf Hertel (Max Born Institut,
Germany), Xavier Solis (Consejo Superior de Investigaciones Científicas - CSIC,
Spain), Xianfan Xu (Purdue University, USA)

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We S1-01
InvitedNano-sized and periodic structures generated by interfering
femtosecond laser processing
Yoshiki Nakata1, Noriaki Miyanaga1, Tatsuo Okada1
1

Institute of Laser Engineering, Osaka University Grad. School of ISEE, Kyushu University

Nanotechnology based on nano-sized structures will innovate the next industrial revolution.
Those structures have been produced by bottom-up techniques such as plasma process,
CVD, laser ablation etc.. These methods have advantages in generation of quite small
structures, but have difficulties in yield, versatility in kind of material, size and structure
control, and alignment. On the other hand, material processing using femtosecond (fs) laser
beam has been utilized to generate nano-sized structures on and in materials. We advanced
the technique to use interfering fs laser beams in wide region, and nano-sized and periodic
structures could be generated. When thin films are processed, nano-sized structures of
nanobump array, nanomesh, nanobelt, dual periodic structure etc. can be generated. They
have characteristic structures and allow us to promote new phase of nanotechnology. In thispresentation, recent results of the generation of new nano-sized structures will be shown.
[1] Y. Nakata, T. Okada, and M. Maeda, Appl. Phys. Lett. 81, 4239 (2002).
[2] Y. Nakata, T. Okada, and M. Maeda, Jpn. J. Appl. Phys. 42, L1452 (2003) .
[3] Y. Nakata, T. Okada, and M. Maeda, Appl. Phys. A 79, 1481 (2004).
[4] Y. Nakata, N. Miyanaga, and T. Okada, to be published on Appl. Surf. Sci. (2007).

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We S1-02
Control parameters for self-organized nanostructure formation
upon femtosecond laser ablation
Juergen Reif1, Olga Varlamova1, Florenta Costache11

Brandenburgische Technische Universitaet Cottbus and JointLab Cottbus

In self-organized nanostructure formation upon femtosecond laser ablation, it has been
observed that the laser polarization is an important control parameter for the type of orderachievable. Experiments on CaF2, using circular and elliptical polarization study thisinfluence in more detail. For circular polarization spherical nanoparticles of about 100 nm
diameter are formed, while with increasing ellipticity longer and longer ordered linear
structures are generated, oriented perpendicular to the long axis of the polarization ellipse. A
similar effect occurs when, instead, for circular polarization the angle of incidence is varied
from normal to 45°. Here, the in-plane component of the incident beam appears to play thesame control function as the long axis before. It determines length and orientation of theordered ripples. For elliptical or linear polarization no such dependence on the angle ofincidence has been observed. Varying the input polarization of the quarter wave plate, used
to generate circular/elliptical polarization, a sharp phase transition in the ripples direction
occurs at a rotation of the input by 90°. When the large axis of the ellipse is rotated behindthe quarter wave plate, the ripples orientation rotates correspondingly. Further, surface
defects like scratches or the edge of deeper craters tend to exert a stronger influence on the
ripples orientation than the polarization, resulting in curved structures bending frompolarization controlled to defect controlled orientation. For modelling the self-organization
process, we still do not have clear evidence about the actual control mechanisms, since thelaser field is no longer present when the structure formation seems to occur. Experiments
superimposing the field of a weak cw-laser did not show any influence. Another approach
may be the generation of surface plasmons surviving much longer which may influence thediffusion properties which plays an important role in the self-organization.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S1-03
Periodic structuring of metals by femtosecond laser pulses
Q. Z. Zhao1, S. Malzer1, and L. J. Wang1
1

Institute of Optics, Information and Photonics,Max-Planck Research Group and University
Erlangen-Nuremberg

Periodic micro-/nano-scale structuring of metals, tungsten, copper, and stainless steel, etc.,
have been investigated by using single beam 800 nm femtosecond (fs) laser pulses
irradiation. Ripple-like periodic structures are formed when the product of the pulse energy
and the pulse numbers meets the threshold condition. The orientation of ripples is aligned
perpendicularly to the direction of laser polarization for linearly polarized light, while +45
degree for left circularly polarized light and -45 degree for right circularly polarized light withrespect to the incident plane of the beam. The period of ripple can be controlled by adjusting
the pulse energy, the pulse numbers, and the incident angle. The experimental results do notfollow the conventional prediction. We discuss a possible mechanism based on theinterference between the incident light pulses and the excited plasma density wave. Our
observation has potential application in large-area structuring of metals. Finally, under
special pulse energy and pulse number conditions, mushroom-like nano-needles are formed
on both the ridge and the valley of the ripple structures.

Fig. 1: Ripple structures on tungsten
surface induced by (a) vertical and (b)horizontal linearly polarized fs pulses,
and (c) left and (d) right circularly
polarized fs pulses, respectively, andMushroom-like nano-needles formed
on both the ridge and the valley ofripples induced by fs pulses; (e) lower
magnification and (f) to (h) increasing
magnification.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S1-04
Standing electron plasma wave mechanism of void array
formation inside glass irradiated by femtosecond laser pulses
Haiyi Sun1, Juan Song1, Jian Xu1, Xinshun Wang1, Ya Cheng1, and Zhizhan Xu1
1

State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine
Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800, China

The interaction of ultrashort laser pulses with transparent dielectrics has attracted muchattention since the advent of the femtosecond (fs) laser, because it can lead to many
interesting phenomena [1,2], such as filamentation, birefringence, formation of periodic voidarray, and so on. Among these phenomena, the formation of periodic void array in the
direction of laser propagation is one of the most puzzling phenomena because of the lack of
a good physical understanding. In this paper, we theoretically analyzed the formation
mechanism of the void array. A regenerative amplified Ti: sapphire laser at wavelength of
800 nm that emits 120 fs, 1 kHz pulses was used in our study. We focused the pulses insidesilica and BK7 glasses using a 100× objective lens (NA=0.9), and the induced characteristic
structure is shown in Fig.1. In particular, we focus our study on the dependence of the periodof the void array on the laser parameters, including pulse energy, pulse number and the focal
depth. The results show that the period of each void array is not uniform along the laser
propagation direction, and the average period of the void array decreases with increasing
pulse number and pulse energy. Based on these experimental phenomena, we propose thata mechanism in which a standing electron plasma wave created by the interference of a fslaser-driven electron wave and its reflected wave is responsible for the formation of theperiodic void arrays. Reasonable agreement between the experimental results and thetheoretical analysis was obtained.
1. S. Kanehira, J. Si, J. Qiu, K. Fujita, K. Hirao, Nano Letters 5, 1591 (2005).
2. E. Toratani, M. Kamata, M. Obara, Appl. Phys. Lett. 87, 171103 (2005).

Fig. 1: Side views of BK7 glass whenirradiate with an average single-pulse
energy of 26.1 μJ focused 400 μm
beneath the sample surface by a 100×
object lensThe 8th International Symposium on Laser Precision Microfabrication

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24-28 April 2007, University of Vienna, Vienna, Austria

We S1-05
Invited
Focussing fs-pulses with optical near-fields
Johannes Boneberg1 and Paul Leiderer1
1

University of Konstanz, D-78467 Konstanz, Germany

The presentation will show how fs-laser pulses can be used to modify surfaces on a scale
well below the diffraction limit. For that purpose the application of spherical particles as wellas the use of optical near-fields of metallic nanostructures will be discussed. Sphericalparticles are easily applied to surfaces e.g. by spin coating. Nevertheless their usage withrespect to dimensions well below the diffraction limit is restricted due to Mie scattering.
There, the intensity enhancement decreases with particle size. At the same time the field
distribution changes from one focus behind the particle to two foci at the side of the particle
as the particle size decrease below the λ/2. For metallic particles or metallic nanoantennas
these limitations do not exist. Field enhancements can be very high, thus very small features(<25nm for λ=800 nm) can be written. Nevertheless other complications exist as there arecomplicated near-fields and interference effects at higher particle densities.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S1-06
Energy coupling and material removal from metallic surfaces
irradiated by temporally-shaped and ultrashort laser pulses
R. Stoian 1, J.P. Colombier 1, E. Audouard 1, P. Combis 2, A. Rosenfeld 3, I.V. Hertel 3
1

Laboratoire Hubert Curien (UMR 5516 CNRS), Université Jean Monnet, 42000 Saint
Etienne, France
2
CEA/DAM Ile de France, Département de Physique Théorique et Appliquée, 91680
Bruyères-le-Châtel, France
3
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany

We discuss the efficiency of energy coupling in laser-irradiated aluminium surfaces byultrashort laser pulses with different intensity envelopes. The approach allows to test particle
ejection from materials subjected to different heating rates. Ion and neutral emission from theexcited sample is used to probe the efficiency of energy deposition in the material.
Subsequently, we examine probable thermodynamic paths for material ejection under thelaser action. With support from numerical simulations of the hydrodynamic advance of theexcited matter, consequences of optimized energy coupling relevant for applications inmaterial processing are revealed. The overall absorption efficiency can be elevated if theproper conditions of density and temperature are met for the expanding material layers. We
show that, in particular irradiation regimes, laser energy delivery extending on several
picoseconds leads to significant superheating of the superficial layers as compared to
femtosecond irradiation and to a swift acceleration of the emitted particles. Subsequently, thelifetime of the post-irradiation liquid layer is diminished, which translates into a reduction in
droplet ejection. Adaptive control of ion ejection from metallic samples via laser-generated
supercritical states allows a certain degree of control in nano-droplets formation from theliquid phase. In contrast, short pulse irradiation at moderate fluences generates a higher
quantity of removed material that is ejected in a dense mixture of gas and liquid-phaseparticulates.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S1-07
Ultra low energy crystallization process for Si by femtosecond
laser irradiation
Yusaku Izawa1, Masayuki Fujita2, Shigeki Tokita1, Takayoshi Norimatsu1, Yasukazu Izawa1
1

Institute of Laser Engineering, Osaka University
2
Institute for Laser Technology

We investigated laser wavelength dependences of crystallization process for Si byfemtosecond laser irradiation, at room temperature in air. The near infrared light above
1100nm is almost transparent for Si. The absorption coefficient for 800 nm light, which is thefundamental wavelength of Ti: sapphire laser, is about 0.0001 nm-1. This value corresponds
to 10 mm as light penetration depth. The absorption coefficient of Si increases withdecreasing the laser wavelength. It is also expected that the laser fluence required inprocessing is smaller for the shorter wavelength lasers. In our experiments, we used thesecond and third harmonic generation by BBO crystal to convert the near infrared light of Ti:
sapphire femtosecond laser into the shorter wavelengths. The fundamental wavelength of
800 nm and the frequency-converted wavelengths of 400 nm and 267 nm laser pulses [100fs pulse width, 1000 Hz repetition rate] were focused on a thin amorphous Si layer [8 nm
thickness] sputtered on a crystalline Si wafer [P type, (100) surface orientation, 99.999 %purity]. To confirm the crystallization process, we performed a high resolution transmission
electron microscope observation. The change of the surface reflectivity was observed bymeans of laser scanning microscope. In three cases, the crystallization occurred below theablation thresholds, the number of pulses required for sufficient crystallization was about
100. The fluences required for crystallization of 800 nm, 400 nm and 267 nm femtosecond
laser irradiation were 100 mJ/cm2, 30 mJ/cm2, and 16 mJ/cm2, respectively. Ultra violet
femtosecond laser is suitable for the fast crystallization of thin amorphous Si layer.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S1-08
Investigations on melting and welding of glass by ultra-shortpulsed laser radiation
Alexander Horn1, Ilja Mingareev1, Alexander Werth1
1Lehrstuhl für Lasertechnik der RWTH-Aachen, Germany

The interaction of laser radiation with pulse durations between 300 fs and 3 ps andwavelength λ = 810 nm with glass like BK7 or D263 glass is detected by pump&probe
techniques. Even with femtosecond laser radiation melt ejection dynamics can be observedin the time-range of 100 ns to 1.4 µs by irradiating a glass on the surface using time-resolved
shadowgraphy. Using ultra-short pulsed laser radiation glass plates are welded together. The
pump beam is focussed by a microscope objective (2ω0 &#61627; 1 µm) into the glass. After
partial absorption of the optical energy the glass is heated. Due to the large intensities in thefocus using high NA objectives multi-photon absorption gets the dominant process and due
to large repetition rates heat is accumulated and meting of the glass is induced. By setting
the intensity of the laser radiation below the ablation threshold glass can be melted insideand on the surface without cracking making welding of glass possible. The modification of atechnical glass (D263 Schott) induced by ultra-short pulsed laser radiation with large
repetition rates up to 5 MHz is observed during welding by time-resolved quantitative phasemicroscopy using ultra-short pulsed white-light continuum as probe beam. The change inrefractive index induced by heating and by compression of the glass is detected.

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Th S1-09
Invited
Non-thermal micro adjustment using ultrashort laser pulses
Peter Bechtold1, Michael Schmidt1
1

Bayerisches Laserzentrum gGmbH

In the field of micro technology highest accuracies have to be attained regarding position,
angles and distances. To achieve this task within reasonable expenses roughly tolerated
assembly followed by high-precision adjustment is often applied. As the final tolerances tend
to get smaller in the same manner as the dimension of the devices common adjustment
processes are reaching limits rapidly. To provide a better solution for this discrepancy theBavarian Laser Center investigates a new process of highly accurate, contact-free and timeefficient micro adjustment for a wide variety of materials using ultrashort laser pulses. Basic
researches have already been accomplished and actual efforts regard process limits,
possible actuator materials, actuator geometry, process robustness, long term stability andindustrial applicability. The process mechanism is based on the effect that an ultrashort laser
pulse of high intensity is able to produce plasma on the surface of the absorbing bulk
material in nearly isochoric manner. The following expansion of the plasma into the confining
medium excites shock waves propagating into the bulk material due to recoil effects. These
shock waves, which rapidly decay to compressional waves, induce near-surface plastic
deformation which results in bending the actuator’s free end away from the laser beam.
Using suitable actuators this can be used for highly accurate adjustment. Results of previous
investigations show that the bending angle can achieve accuracies in the scale of a few 10µrad while allowing maximum deflections of a few degrees. Up to now copper, steel, silicon
and pyrex-glass have been successfully deformed with this process.

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Th S1-10
Nanostructuring with femtosecond laser pulses on patterned
DLC surface
G.Miyaji1, Y.Miyatani1, and K.Miyazaki1
1Institute of Advanced Energy, Kyoto University

Recent laser ablation experiments have shown that superimposed fs-laser pulses at low
fluences can produce periodic nanostructures as small as 1/10 of laser wavelength on hardthin films such as TiN and diamond-like carbon (DLC) [1], suggesting a potential nanoprocessing technology with fs lasers. We report a preliminary experiment to demonstrate our
proposal for the origin of nanostructuring on the thin film surface. The target was fabricatedon Si substrate. Using electron-beam lithography and liftoff process, the Si surface waspatterned with parallel lines of 200-1600 nm in interval, each of which is 100-500 nm in width,
50 nm in height, and 4500 nm in length. DLC of 900 nm in thickness was deposited on thepatterned Si surface. This target was irradiated with multiple shots of linearly polarized, 100fs, 800-nm laser pulse at low fluence, and the surface morphology was observed with ascanning electron and/or probe microscopes. The results have shown that the nanostructureoriented to the direction perpendicular to the laser polarization is formed on both of thepatterned and non- patterned surface areas. However, we have found a significant difference
between structures on the patterned and non-patterned areas. The mean spacing of
nanostructure on the latter was about 100 nm or less, being in accordance with the previous
observations [1]. On the other hand, much larger and deeper structure was created near andon the parallel lines, as if the patterned area were irradiated at higher fluence. This
characteristic structure was observed only in the vicinity of the lines perpendicular to thelaser polarization. This observation demonstrates that the nanostructure is created with
nano-scale local fields enhanced around the surface pattern, as proposed in our study [2]. [1]
N.Yasumaru, K.Miyazaki, and J.Kiuchi, Appl. Phys. A 76, 983 (2003); 81, 933 (2005). [2]G.Miyaji and K.Miyazaki, Appl. Phys. Lett. 89, 1919002 (2006).

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S1-11
Silica-based nonplanar structures fabricated by femtosecond
laser lithography and plasma etching
Mizue Mizoshiri 1, Hiroaki Nishiyama1, Junji Nishii2, Toshio Kawahara3,
Tomoji Kawai3, Yoshinori Hirata1
1

Division of Materials and Manufacturing Science, Graduate School of Engineering,Osaka University
2
National Institute of Advanced Industrial and Science Technology
3
The Institute of Scientific and Industrial Research, Osaka University

Silica-based diffractive optical elements (DOEs) were widely used in many applications suchas optical pickups. The nonplanar elements such as blazed gratings and micro-Fresnel lens
were useful for high diffractive efficiencies. However, it is rather difficult to fabricate silicabased nonplanar microstructures by conventional semiconductor technology including
lithography and plasma etching processes. In our study, silica-based micro-Fresnel lenses
were fabricated on silica substrates by femtosecond laser lithography followed by plasma
etching. Resist patterns of micro-Fresnel lens were written in a chemically amplified
negative-tone photoresist KMPR-1050 on silica substrates utilizing multi-photon absorption
induced by femtosecond laser. We utilized filamentation induced by femtosecond laser
pulses for the resist patterning to reduce the scanning sequences. Then, resist patterns weretransferred to the silica substrate by plasma etching with CHF3 and O2 mixed gas. Figure 1
shows a silica-based micro-Fresnel lens. The diameter and the height were 280 um and 5
um, respectively. The micro-Fresnel lenses with smooth surfaces were obtained. We are now
trying to fabricate a silica-based diffractive/refractive hybrid lens by the combination processof femtosecond laser lithography and plasma etching. The preparation and characterizationof the hybrid lens will be reported in detail.

Fig. 1: SEM image of silica based
micro Fresnel lens fabricated byfemtosecond
laser
lithography
followed by plasma etchingThe 8th International Symposium on Laser Precision Microfabrication

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S1-12
Lithography-free, high resolution polymer transistors byconductive polymer laser ablation
Dr. Seung Hwan Ko1, Heng Pan1, Prof. Costas, P. Grigoropoulos1, Prof. Dimos Poulikakos1
1

University of California at Berkeley, USA ETH at Zurich, Switzerland

OFETs (organic field effect transistors) with air stable carboxylate-functionalized
polythiophene semiconducting polymer as active layer were fabricated and characterized.
Conductive polymer was used as electrodes. After depositing the conductive polymer,
focused pulsed laser was applied to define high resolution channel with micron to submicron
critical feature resolution in a fully maskless sequence, eliminating the need for any
lithographic processes. All processing and characterization steps were carried out at plasticcompatible low temperatures and in air under ambient pressure.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S1-13
InvitedMicro-filamentation induced permanent structural modifications
in fused silica with intense sub-picosecond ultraviolet laser
pulsesD.G. Papazoglou1,2, I. Zergioti3, S. Tzortzakis1
1Foundation for Research and Technology – Hellas, Institute of Electronic Structure andLaser, P.O. Box 1527, Heraklion 711 10, Greece
1
Department of Materials Science and Technology, University of Crete,
71103 Heraklion, Greece,3
National Technical University of Athens, Physics Department,
Iroon Polytexneiou 9, 15780 Zografou, Athens, Greece

We report on the temporal dynamics of sub-picosecond ultraviolet laser pulse microfilamentation in the bulk of fused silica. Using a high resolution pump-probe imaging
technique we monitor the formation of plasma micro-filaments. Interestingly, single shot
permanent structural modifications are observed only in areas where the electron density
exceeds a threshold value of ~ 4×1019 cm-3. The length of the permanent modifications
increases with pulse accumulation while saturates after a few hundreds of pulses. From thissaturation we can extract a lower limit of the electron density. Applications in photonic
devices will also be discussed.

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Th S1-14
Tailored femtosecond pulses for nanoscale laser processing ofwide band gap materials
L. Englert1, B. Rethfeld2, L. Haag1, C. Sarpe-Tudoran1 and T. Baumert1
1

Universität Kassel, Institut für Physik und CINSaT,
Heinrich-Plett-Str. 40, D-34132 Kassel, Germany,2
Gesellschaft für Schwerionenforschung,Planckstr. 1, D-64291 Darmstadt, Germany

Lasers delivering ultrashort pulses have emerged as a promising tool for processing wideband gap materials for a variety of applications ranging from precision micromachining on
and below the wavelength of light to medical surgery [1]. It is the transient free-electron
density in the conduction band of the dielectric that plays a fundamental role in addition tovarious propagation and relaxation mechanisms that in the end lead to phase transitions or
the creation of voids. A large number of experiments devoted to the study of the microscopic
ionization processes makes use of the threshold of observed damage as experimental
evidence for exceeding a certain critical electron density after the laser interaction. These
involve pulse duration measurements [2] and recent pulse-train experiments [3] all showing astrong dependence of the damage threshold on pulse duration and on pulse separation. In
our work we make use of temporally asymmetric femtosecond pulses of identical fluence,
identical spectral distribution and identical pulse duration in order to control photoionizationand electron-electron impact ionization. Control leads to different final electron densities as
the direct temporal profile and the time inverted profile address the two ionization processes
in a different fashion. This results in observed different thresholds for material modification in
fused silica ans sapphire as well as in reproducible lateral structures being an order ofmagnitude below the diffraction limit. [1] H. Misawa and S. Juodkazis, 3 D Laser
Microfabrication WILEY-VCH Verlag GmbH & Co. KGaA, 2006. [2] A. C. Tien, S. Backus, H.
C. Kapteyn, M. M. Murnane, and G. Mourou, Phys. Rev. Lett. 82, 3883-3886 (1999). [3] R.
Stoian, M. Boyle, A. Thoss, A. Rosenfeld, G. Korn, I. V. Hertel, and E. E. B. Campbell, Appl.
Phys. Lett. 80, 353-355 (2002).

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Th S1-15
Structural transformation dynamics below and above theablation threshold in fused silica upon single pulse femtosecond
laser irradiation
J.Solis1, J.Siegel1, D. Puerto1, J. Bonse2 , G. Bachelier3
1

Laser Processing Group, Instituto de Optica,
C.S.I.C., Serrano 121, E-28006 Madrid, Spain
2
Present address: Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie,
Max-Born-Strasse 2A, D-12489 Berlin, Germany
3
Present address: Laboratoire de Spectrometrie Ionique et Moleculaire, Universite Claude
Bernard Lyon 1- CNRS (UMR 5579), 43 Boulevard du 11 Novembre 1918,
F-69622 Villeurbanne Cedex, France

We have used time-resolved microscopy in order to investigate the temporal and spatial
evolution of the ablation process in fused silica upon irradiation with single femtosecond laser
pulses at 800 nm. Images of the surface reflectivity at 400 nm have been recorded at
different delays, covering a time span from ~ 100 fs up to 20 ns. The quantitative analysis of
the image sequence allows to determine the ultrafast evolution of the reflectivity of thesurface at different local fluences. The observed reflectivity changes have been correlated tothe density and spatial extension of the free-electron plasma formed upon laser exposure.
The results show that an annular transient plasma region is formed outside the ablating
region for fluences in a narrow window below the ablation threshold. This outer region is
spatially coincident with a subtle structural transformation observed with light microcopy after
irradiation. The material in this annular zone is structurally modified after irradiation andshows a reflectivity increase of app. 3% with respect to the non irradiated material. This isconsistent with a refractive index change of 0.01, similar to the values reported upon fs laser
irradiation inside bulk fused silica for the production of optical waveguides. To the best of ourknowledge, this effect, being common inside bulk silica, has not been reported before insurface irradiation experiments. This structural modification below the ablation thresholdwould play a major role in the results induced upon multiple pulse laser exposure and help inunderstanding the role of incubation effects.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S1-16
Dynamic correction of optical aberrations during ultrafast laser
photoinscription of waveguides in bulk transparent materials
C. Mauclair1, A. Mermillod-Blondin1, N. Huot1, E. Audouard1, and R. Stoian1
1

Laboratoire Hubert Curien (UMR 5516 CNRS), Université Jean Monnet, 18 rue Prof. Benoit
Lauras, 42000 Saint Etienne, France

The quality of a laser beam as well as the flexibility in tailoring intensity envelopes is
becoming important in material processing applications in view of the demands of accuracy
in the machining process. When 3D processing of structures with optical functions in bulk
transparent materials is concerned, the linear and nonlinear propagation of the processing
light beam is affected by its own spatial characteristics. For example, spatial beam distortions
are often detrimental for the process of laser photoinscription of wave guiding elements inbulk transparent materials. Consequently, the axial redistribution of energy depends on thespatial characteristics of the incoming laser beam upon focusing in the bulk material,
influencing therefore the dimensions and the nature of the laser-induced material
modification. Spherical aberrations are usually induced during refraction at air-dielectricinterfaces, creating a dependence of the deposited energy density on the depth of writing.
We present in the following a procedure of dynamic correction of optical aberrations duringlongitudinal photoinscription in BK7 optical glass. The procedure involves the adaptive
control of the spatial phase of the incoming beam using programmable spatial shaping of
ultrafast laser pulses and relies on a positive feedback loop based on phase-contrast
microscopy detection of laser-induced modifications.

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24-28 April 2007, University of Vienna, Vienna, Austria

Fr S1-17
InvitedOverview of laser micro/nanoprocessing mediated with nearfield - the state of the art and future perspective
Minoru Obara1, Tetsuo Sakai1, Tomoya Miyanishi1, and Nikolay N. Nedyalkov1
1

Department of Electronics and Electrical Engineering, Keio University, 3-14-1 Hiyoshi,
Kohoku-ku, Yokohama, 223-8522 Japan

In this talk, we will experimentally and theoretically overview the laser micro and nanoprocessing mediated with near field and then describe the future perspective of the near fieldlaser processing. The precise nanostructuring of various materials attracts a growing interestin recent years. This is related to the need for development of new optical, photonic andtribology components for micro and nano devices, and also related to the new effects andphenomena at such dimensions. Various methods and techniques are proposed anddeveloped for producing nanostructured materials by means of electron and ion beamlithography, laser lithography, and direct laser write 2D and 3D structuring. Among thedeveloped methods a promising technique would be to use a near-field of the dielectric
particles due to Mie scattering, and a low dimension of the resonant plasmon field produced
in metal nanostructures. If the diameter of the dielectric particle is smaller than the
wavelength, a light enhancement effect may occur due to the near field scattering crosssection based on the Mie’s theory. The effect of the laser fluence, polarization, particle size
and arrangement, on the nanohole properties is studied. Transparent spherical particles areplaced on various substrate surface and nanoholes are fabricated at the original position of
the particle using femtosecond laser. In the meantime, due to the effective coupling of theincident laser to the plasmon oscillation a significant enhancement of the field in vicinity ofthe metal structure can be produced. The main advantage of the two techniques is that thesize of the field enhanced zone is governed not by the wavelength and polarization of theincident radiation, but by the size of the illuminated metal and dielectric structures. Finally wewill focus on the promising prospective of the near field laser nanostructuring in photonics,
electronics and tribology.

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24-28 April 2007, University of Vienna, Vienna, Austria

Fr S1-18
Ultrafast laser processing of metals: New tools and new results
J.p. Colombier1, D. Brunell1, C. Donnet1, N. Huot1, R. Stoian1 and E. Audouard1
1

Laboratoire Hubert Curien, CNRS UMR 5516, Université Jean Monnet

Ultrafast laser sources are considered as a promising tool for new micromachining
applications. In the case of metals, a deep understanding of the main laser matter interaction
mechanisms is now reached and relevant simulations can be done. At the same time, newapplication fields are reaching the industrial step. We will show also that increasing therepetition rate of laser sources can lower the processing time, by the use of sources basedon a single non-cryogenic regenerative amplifier which produces after compression up to
350-µJ and 60-fs pulses at a 10 and 15 kHz repetition rate.A detailed model of the ultrashort
response to reproduce ablation process is presented, describing dynamical electronic
properties such as temperature, pressure and energy. To simulate the interaction between
the laser and the metallic target, these theoretical models are inserted inside a 1D
Lagrangian hydrodynamic code. We point out to the role of strong isochoric heating as amechanism for producing highly non-equilibrium thermodynamic states. In the case of
metals, the conditions of material ejection from the surface are discussed in a hydrodynamic
context, allowing correlation of the thermodynamic features with ablation mechanisms. An
estimation of the amount of material exceeding the specific energy required for melting isreported for copper and aluminium and a theoretical value of the limit-size of the recast
material after ultrashort laser irradiation is determined. A specific application will be shown in
the field of microtexturation of metallurgical surfaces and coatings. The objective is to reduce
friction and wear in various lubrication regimes. The use of femtosecond laser pulses
improves the achievable quality of the microstructures on any kinds of materials, incomparison to nanosecond laser pulses because of the minimized heat affected zone. Underrolling–sliding conditions, the film thickness distribution is modified, and specific effects canbe point out.

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24-28 April 2007, University of Vienna, Vienna, Austria

Fr S1-19
InvitedPulsed laser deposition using femtosecond laser radiation andplasma filtering
Thomas Höche 1,2, Frank Ulmer 2, Christiane Leschinski 2
1

2

3D-Micromac AG, Annaberger Straße 240, D - 09125 Chemnitz, Germany
Leibniz-Institut für Oberflächenmodifizierung e. V., Permoser Straße 15, D - 04318 Leipzig,
Germany

When femtosecond lasers became available, huge expectations in regard of their utilisation
for pulsed laser deposition (PLD) were raised. This was due to their ability to ablate all solid
matter (via multiphoton absorption), the extraordinarily high pulse power (together with very
short interaction times leading to mainly electronic excitations), and the highly ionised
ablation plasma. It was believed that a high degree of ionisation would allow to deposit highquality thin films without impairment by particulates. However, browsing through current
literature reveals that PLD using femtosecond lasers is not yet widely used. This is related to
two facts. First, due to small pulse energies, deposition rates are very low and second, andmore importantly, in the very dense plasma, a large number of condensation droplets with afew 100 nm diameter is formed. In the end, the latter particulates are so dominating that thinfilm quality is inferior. We have designed and build a UHV PLD workstation (currently
operated in combination with a chirped-pulse amplification 775 nm Ti:sapphire laser, 130 fs
pulse length, 1 kHz repetition rate) to study the mechanism of femtosecond laser depositionin greater depth. With this experimental setup, we have been investigating ultrathin-layer
deposition of various rare metals as well as complex nitrides. Three general principles forparticulate suppression were evaluated, including filtering by a transverse magnetic field, abias supplied to the substrate, and scattering at a background gas. All of those methods
proved viable, however, on the expense of the already very small deposition rate. Therefore,
we are currently designing and testing a dedicated high-throughput plasma filter and first
results of this development will be presented. Our PLD chamber equipped with a dedicatedplasma filter will become a very valuable extension for preexisting ultrashort-pulse laser
workstations enabling the generation of high-quality thin films.

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24-28 April 2007, University of Vienna, Vienna, Austria

Special Session 2 (LPM-S-2):

3D Micro- and Nanomachining(Ultrafast Laser processing, buried optical circuits,
photonic bandgap materials etc.)

Session Organizers:
Boris Chichov (Laser Zentrum Hannover, Germany), Minghui Hong (DSI-Data
Storage Institute, Singapore), Alberto Piqué (Naval Research Laboratory, USA),
Yoshiro Ito (Nagaoka University of Technology, Japan)

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-01
Invited
3D write-read-erase memory bits by femtosecond laser pulses inphotorefractive LiNbO3 crystal
Eugene Gamaly1, Saulius Juodkazis2, Vygantas Mizeikis2, Hiroaki Misawa2,
Andrei Rode1, Wieslaw Krolikowski1
1

Laser Physics Centre, Research School Of Physical Sciences and Engineering,
The Australian National University, Canberra ACT 0200, Australia
2
CREST-JST and Research Institute for Electronic Science, Hokkaido University,
Sapporo 001-0021, Japan

We present results of experimental and theoretical studies of the formation of refractive index
voxels in photorefractive crystals with high power femtosecond laser pulses. We used 150fs
pulses at 800nm wavelength (energy 6-130nJ) tightly focused inside the iron-doped lithium
niobate crystal in a single shot regime [1]. This resulted in a formation of a micrometer size
(2xx2yx8z ?m3) region of elevated refractive index which may be used as memory bits in
information storage/retrieval application [2]. The index contrast as high as 10-3 has beenobtained with an average light intensity of ~Tw/cm2 that is close to the breakdown thresholdin dielectrics [see Fig.1(a-b)]. The writing process is independent of the polarization of thelaser beam and is fully reversible. Once written local modulation of the refractive index canbe removed (erased) by the action of a low intensity broad beam and induced again at thesame place (re-written) by using a tightly focused pulse. Up to 20 same-spot rewriting cycles
have been performed without any deterioration of the recorded bits. Moreover, by moving the
crystal in vertical direction few independent layers of bits have been recorded [see Fig.1(c)].
In this talk we discuss various aspects of the recording/erasing process including
mechanisms of laser absorption, electron excitation and recombination, formation of charge
separation field, as well as methods for control of the size and longevity of the refractive
index changes. The analysis shows that the photovoltaic effect [3] is mainly responsible forthese changes. The presented results suggest the possibility of suitability of properly chosen
femtosecond pulses for fast 3D write-read-erase optical memory application.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-02
Multi-lens array fabrication and its applications in laser precisionengineering
M.H. Hong1, F. Ma1, C.S. Lim1, Y. Lin1, Z.Q. Huang1, L.S. Tan1, L.P. Shi1 and T.C. Chong11Data Storage Institute, ASTAR, Singapore 117608

Slow processing speed is one of technical bottlenecks in laser precision engineering,
especially as the processing resolution reduces down to sub-micron or even nanometerscale. Laser micro- & nano-fabrication of multi-lens array (MLA) is investigated by both laser
direct writing approach and interference lithography, following with thermal reflow andreactive chemical etching. It is found that a large area (up to 1 cm2) MLA can be madeuniformly on the transparent substrate with the lens diameter from 500 nm to 500 μm. The
fabricated MLAs are used in the optical microscope and laser beam shaping to enhance
imaging quality and tune laser beam profile for the top flat beam surface processing. With thespecial design of MLA scanning directions with the MLA orientation, surface multiplexing canbe achieved. Meanwhile, different laser sources from UV to IR spectra and different pulse
durations from 100 fs up to dozens of ns are used to fabricate different submicron/nanometer resolution surface structures in parallel. With the laser irradiation througha MLA on a sample surface immersed inside a chemical solution, high speed and large area
sub-micron structure deposition under laser induced photo-chemical reactions is studied for
micro/nanostructure fabrication as well.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-03
Three-dimensional femtosecond laser microfabrication
Hiroaki Misawa1, Saulius Juodkazis1
1

RIES, Hokkaido University, Sapporo 001-0021, Japan

Three-dimensional (3D) structuring of glasses, ceramics, crystals, and polymers by tightly
focused femtosecond laser pulses is a promising technique for microfluidic, micro-optical,
photonic crystal and micro-mechanical applications [1-4]. The 3D laser micro-structuring ofresists is demonstrated by direct laser writing [1] and holographic recording using phase
control of interfering pulses [2]. Flexibility of the phase control method is demonstrated byforming a log-pile photonic template out of a tetragonal body centered structure byinterference. 3D photonic crystal templates with stopband at a shorter than 1 micrometer
wavelength have been achieved in resist by modified direct laser writing. Tightly focusedlaser pulses can reach dielectric breakdown irradiance without self-focusing when sub-1 ps
pulses are used inside dielectric. The mechanism of void formation [3] has been explained.
The absorption in the plasma at focus is localized within a skin depth of tens-of-nanometers.
This defines an ultimate localization of the energy delivery by a laser pulse. The hightemperature and pressure buildup can be large enough to generate a shock wave (strong
micro-explosion). A single 100 nJ laser pulse forms a void under tight focusing conditions
even in the high strength sapphire (Young modulus of 400 GPa). This opens new material
processing routes for inert dielectrics [4]. Altered chemical properties of shock-affected
regions inside silica glass, quartz, and sapphire were revealed by wet etching of “shocked”
regions in aqueous solution of hydrofluoric acid. The achievable resolution limits andpotential of the fabricated 3D patterns in photonics, microfluidics, and sensor applications are
discussed.
[1] K. K. Seet et al., Adv. Mat. 17, 541, 2005.
[2] T. Kondo, et al., New J. Phys. 8, 250, 2006.
[3] S. Juodkazis, et al., Phys. Rev. Lett. 96 166101 2006.
[4] S. Juodkazis, et al., Adv. Mater. 18 1361 2006.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-04
3-D micro fabrication of mechanical systems using laser basedstereo lithography
A. Neumeister1, R. Himmelhuber2, T. Temme1, U. Stute1, A. Ostendorf1
1

Laser Zentrum Hannover e.V.
micro resist technology GmbH2

Within the presented work, we demonstrate the fabrication of micro mechanical systems byusing laser based stereo lithography. For that aim, a high resolution machining setup for thecreation of three-dimensional precision components from a UV-curable photo-resin has beendeveloped. Functional micro-mechanical devices that include movable components arefabricated within a one step production without the need of assembling individual parts. The
layer-by-layer fabrication process is directly based on user defined CAD data that will besliced at a constant increment. For illumination purpose, a frequency-converted diodepumped solid-state laser is applied, providing high structural surface quality due to arepetition rate of 100 MHz. Specially designed materials from the type Ormocere b59 offer ahigh process resolution up to 10 µm in both lateral and vertical dimension. In particular, we
present the modification of the resin material and the consequences on the processresolution to achieve the suitability for micro stereo lithography.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-05
Two-photon polymerization system for research and industrial
applications
Sven Passinger1, Roman Kiyan1, Aleksandr Ovsianikov1, Carsten Reinhardt1, and Boris
Chichkov1
1

Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 HannoverTwo photon polymerization (2PP) is a very promising technique offering new possibilities in
micromechanical, microoptical, and biomedical applications. In this contribution, thedevelopment of a 2PP system for industrial applications is reported. The topic of surface
plasmon polaritons is taken as an example for the application of 2PP. Waveguides, Bends,
Splitters, Couplers and other plasmonic structures are fabricated by two-photon induced
polymerization of a high refractive index in-organic-organic hybrid polymer. The SPP
structures are investigated in the far-field by a leakage radiation setup for their plasmonexcitation and -guiding properties. As an example Fig. 1 shows on the left a SEM image of acurved structure fabricated by 2PP. On the right the plasmon excitation is observed in aleakage radiation setup. Quality of 2PP structures fabricated with different writting speeds
are compared and a high speed, high quality, and large area 2PP structuring isdemonstrated.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-06
InvitedNanostructuring with nanojoule femtosecond laser pulses
R. Le Harzic 1,2, H. Schuck 1, F. Bauerfeld 1, D. Sauer 1, T. Velten 1, P. Becker 1,
E. Lai 1, M. Stark 1, K. König 1
1

Fraunhofer Institute of Biomedical Technology (IBMT),
Ensheimer strasse 48 D-66386 St. Ingbert, Germany
2
JenLab GmbH, Schillerstrasse 1, D-07745 Jena, Germany, www.jenlab.deSub-wavelength multiphoton nanoprocessing of silicon wafers, direct nanowriting of metals
or polymers, laser processing for nanofluidics applications as well as 3D maskless
lithography by two two-photon polymerization in combination with five-dimensional(x,y,z, , ) multiphoton analysis have been performed using several compact near infrared
MHz femtosecond lasers as tuneable turn-key, one-box Chameleon (coherent) and Mai-Tai(spectra physics) oscillators as well as a special femtoTrain system (High Q laser). The
lasers were coupled with scanning microscopes as the FemtOcut (JenLab GmbH) device aswell as a modified ZEISS LSM510-NLO system. Nanostructuring of silicon wafers was basedon NIR laser-induced periodic surface structures (LIPPS) likely due to self-organization
processes. Periodic structures of less than 400 nm were performed at a wavelength of 1035
nm in air. For the first time, periodic 70nm nanogrooves have been generated in wafers using
oil immersion objectives which is one order below the 800 nm [1]. Nanogrooves of 150200nm can be achieved by UV direct writing at 345 nm. Three-dimensional two-photon
polymerization in SU-8 photoresists at allowed rapid prototyping with sub-200 nm precision.
MHz femtosecond laser pulses with nanojoule photon energies can be considered as novel
tools for nanoprocessing in material science, nanobiotechnology and nanomedicine.
[1] R. Le Harzic, H. Schuck, D. Sauer, T. Anhut, I. Riemann, T. Velten, K. König, “Sub-100
nm nanostructuring of silicon by ultrashort laser pulses”, Optics Express, 13, 6651-6656(2005).

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-07
Optical and vibrational properties of self organized silver
nanocolumns
J. Margueritat1,2, J. Gonzalo1, C. N. Afonso1, A. Mlayah2, D. B. Murray3, L. Saviot4
1

Instituto de Optica, CSIC, 121 Calle Serrano, 28006, Madrid, Spain
Centre d'Elaboration de Matériaux et d'Etudes Structurales, Université Paul Sabatier-CNRS,
31055 Toulouse, France
3
Mathematics, Statistics and Physics Unit, University of British Columbia Okanagan,
3333 University Way, Kelowna, British Columbia, Canada V1V 1V7
4
Institut Carnot de Bourgogne, UMR 5613 CNRS, Université de Bourgogne,
9 avenue A. Savary, BP 47870-21078 Dijon, France

2

The optical properties of silver nanostructures are determined by the absorption at thesurface plasmon resonance (SPR) wavelength which depends on their morphology. The
vibrational properties also depend on the morphology and are particularly interesting for
SERS applications. Further tuning of the SPR can be achieved through the synthesis ofcomplex nanoparticles with taylored sizes and shapes. Among possible ways for achieving acontrol on the morphology, we have recently produced self aligned nanocolumns in the
direction perpendicular to the substrate. The aim of this work is to explore the interaction
between surface plasmons and vibrational modes in such “nanodesigned” composites
formed by oriented metal nanocolumns embedded in a dielectric host. In a previous work, wehave successfully used pulsed laser deposition to produce silver nanoparticles in an
amorphous Al2O3 host. The nanoparticles are located within layers whose separation caneasily be controlled. This technology has been extended to produce self-assembled
nanocolumns by reducing the distance between consecutive layers. The analysis of
nanocolumn morphology shows that they have a diameter of 2.7 nm and a height of 6.7 nm,
which corresponds to an aspect ratio around 2.5. The non-spherical shape of thenanoparticles is evidenced in the optical absorption spectra through the presence of thelongitudinal and transverse SPRs located respectively at lower and higher wavelength thanthat of spherical nanoparticles. Under resonant excitation of the longitudinal surface
plasmons a low frequency band is observed in the Raman scattering spectra, which is
assigned to the spheroid-like vibration mode (l=2, m=+2,-2)of the nanocolumns. The
corresponding vibration frequency calculated using molecular dynamics simulations agrees
well with the experimentally measured frequency. The reported results shed light on theplasmon-phonon interaction in metal nano-objects.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S2-08
Characteristics of internal melting of glass for fusion welding
using ps laser pulses with average power up to 8W
Isamu Miyamoto1, Thomas Herrmann2
1

Osaka University; Japan
Lumera Laser GmbH, Germany

2

Glass is an attractive material for devices such as MEMS, µ-TAS, electronics andbiomedicals due to its excellent optical, mechanical and chemical properties. It is required todevelop reliable and high-throughput joining technique without pre- and post-heating andinter layers. Picosecond laser is an excellent tool for fusion welding of glass, which enables
joining of glass plates very efficiently by selective melting of the interface of the glass plates[1]. This paper discusses characteristics of internal glass melting using10ps laser with highpulse repetition rates up to 1MHz and high average power of 8W from Lumera Laser GmbH.
The effects of pulse energy, repetition rate, lens NA and focus position on the nonlinear
absorptivity, melt dimensions are extensively determined at a velocity range of 1-500mm/s
for different glass materials (fused silica, pyrex glass, crown glass and display glass (Shott
D263)) having different band gap energies. The melt dimensions are analyzed based onthermal conduction model [1]. The threshold energy of the nonlinear absorption was nearly
constant ~0.2µJ despite of large difference in band gap energy, except for D263 ofsomewhat larger value of 0.3µJ, as is shown in Fig. 1. Local melting of fused silica was
obtained without cracking at high average power level of 6W, while cracks are easily
developed at low average power. Figure 2 shows the laser- melted cross-sections of fusedsilica between 500kHz and 1MHz at 6W. It is interesting to see that the melted regions in
500kHz are larger than 1MHz, indicating that lower pulse repetition rate provides larger
melting region.
[1] I. Miyamoto et al: Local melting of glass material and its application to direct fusion
welding by ps-laser pulses, JLMN, Vol. 3, No.1 (2007) to be publishedFig. 1: Nonlinear absorptivity vs. pulse Fig. 2: Melt cross-section at different
energy at pulse repetition rate of 640 travelling velocities at 500 kHz and 1
MHz in fused quartz
kHz

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We S2-09
Femtosecond laser direct fabrication of 3D microopticalcomponents buried inside of photosensitive glass
Zhongke Wang1, Koji Sugioka1 and Katsumi Midorikawa1
1

Laser Technology Laboratory, RIKEN – The Institute of Physical and Chemical Research,
Hirosawa 2-1, Wako, Saitama 351-0198, Japan

Recent years, microchip devices are of great interests and have received the much attention
for highly efficient performance of chemical analysis, biosensing, medical inspection, etc.
with great ease of use. As a result, these demands have drived the significant progress in the
fabrication and incorporation of microoptical circuits into microfulidic circuits inside the bulk ofa transparent material using femtosecond laser micromaching [1]. With the developing inapplication, the enhanced functionality of these microchips has put out more and more therequirements of a wide variety of optical structures in the construction of fluidic photonic
integrated devices, for example, the integrated light collimating system with microlens andslits for a highly efficient and sensitive absorbance detection in a capillary electrophoresis
microchip [2], etc. In this work, we demonstrate the fabrication of the cylindrical microlens
and hemispherical plane-convex microlens embedded inside of bulk Foturan photosensitive
glass using fs laser direct writing followed by programmed thermal treatment and successive
wet etching. Fabrication of the cylindrical and hemispherical plane-convex microlenses madeof the Foturan glass by the fs laser processing has been reported [3]. In this case, however,these microleses were gouged out from the bulk. In the meanwhile, in this paper, themicrolenses which consist of hollow structures are truly embedded inside of the Foturan
glass. The functionality of the fabricated microlenses and the integration with mirror andwaveguide will be shown in detailed in this presentation.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-10
InvitedIntegration of multifunctions in glasses using 3D femtosecond
laser microfabrication
Ya Cheng1, Zhizhan Xu1, Ruxin Li1, Wenqi Zhang Koji Sugioka1 and Katsumi Midorikawa1
1

State Key Laboratory of High Field Laser Physics, SIOM Laser Technology Laboratory,
RIKEN

Integrating multifunctions into a common substrate poses a formidable challenge to microand nano-fabrication. Generally, micro-components of different functions need to befabricated on different substrate materials by different technical approaches. Integration of
the micro-components into a fully functional micro-device requires cumbersome assemblyand packaging processes. Recent advances in femtosecond laser microfabrication provide a
potential solution to this tough issue. In this paper, we describe the formation of optical,
fluidic, electronic, and plasmonic elements on either photosensitive or non-photosensitive
glasses as well as their integrations using femtosecond laser microfabrication. Particularly,
we highlight the integration of microfluidics and microoptics in glass chips which leads to aseries of key elements such as tunable optical waveguides and microfluidic lasers for lab-ona-chip application. Shown in Fig. 1 is a single mode microfluidic optical waveguide fabricatedon a microscope cover glass slip. In this waveguide, refractive-index-optimized liquid is fed
into a microfluidic channel fabricated by femtosecond laser direct writing, which serves as thecore of the waveguide. Lastly, we comment on several technical barriers currently existing,and suggest the potential solutions to them.

Fig. 1: Demonstration of microfluidic
optical waveguide using a He-Ne Laser

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Th S2-11
Femtosecond-laser induced negative refractive index shift inthin film Ge0.23Sb0.07S0.70 chalcogenide glass
T. Anderson1, N. Carlie2, L. Petit2, J. Hu3, A. Agarwal3, J.J. Viens3,
J. Choi1, L.C. Kimmerling3, K. Richardson2, M. Richardson[1]1College of Optics/CREOL, University of Central Florida,
4000 Central Florida Blvd., Orlando, FL 32816
2
Clemson University, 91 Technology Dr., Anderson, SC 29625
3
Microphotonics Center, Massachusetts Institute of Technology,
77 Massachusetts Ave., Cambridge, MA 02139

We present a study of the response of thin film Ge_{0.23}Sb_{0.07}S_{0.70} chalcogenide
glass to 800nm femtosecond laser irradiation. Lasers with 1kHz (Spitfire, Spectra Physics)
and 80MHz (Ti:sapphire oscillator, KMLabs) repetition rates are used to investigate theresponse of the material to femtosecond pulses. The laser was focused using a 0.25NA 10X
microscope objective and defect lines were created in the films by translating the glass
through the focal region. Films fabricated using both thermal evaporation and pulsed laser
deposition were irradiated with irradiances below the ablation threshold. The glass exhibited
photo-expansion as a result of irradiation that was a function of both the laser irradiance andthe translation speed of the sample. The height of the photo-expansion, measured with a
Zygo NewView 6300 white light interferometer, was ~4nm for irradiation with kHz repetition
rate pulses and ~40nm for irradiation with MHz repetition rate pulses, indicating that the
response of this glass composition is sensitive to cumulative effects. Irradiation with the MHz
repetition rate laser induces a negative shift of the refractive index of the films (Δn ~ - 0.03).
The dependence of Δn on the number of pulses incident on the sample per focal spot andthe irradiance is shown in the figure. The Δn was measured using both an interferometrictechnique and the Swanepoel method. Using the interference technique, the refractive index
change was seen as a shift in an interference pattern created between a reference flat andthe back surface of the film. The Swanepoel method was used to calculate the refractive
index of the film through an analysis of the interference fringes of the transmission spectrum
before and after irradiation. The bond structure of the glasses before and after irradiation as
measured by micro-Raman spectroscopy is also discussed. The authors acknowledge Barry
Luther-Davies and CUDOS for the film deposition using the PLD technique.

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Th S2-12
Microfabrication of nonplanar surface structures by
femtosecond laser lithography
Hiroaki Nishiyama 1, Mizue Mizoshiri 1, Tomohiro Iba 1, Junji Nishii 2, Toshio Kawahara 3,
Tomoji Kawai 3, and Yoshinori Hirata 1
1Osaka University, Japan
2
AIST, Japan
3
ISIR, Japan

Femtosecond laser polymerization has received much attention because this technique is a
powerful tool for three-dimensional patterning of photosensitive resin with subdiffraction-limit
spatial resolution. In this study, silica-based nonplanar surface microstructures were createdby femtosecond laser lithography followed by plasma etching for integrated opticalcomponents. The center wavelength, pulse duration, and repetition rate of femtoseond fiber
laser used are 800 nm, 68 fs, and 50 MHz, respectively. Figure 1 shows a SEM image ofsilica-based line patterns on the step structures. First, a chemically amplified negative-tone
photoresisit were spin-coated on the silica-based step structures which were fabricated byconventional semiconductor technology in advance. Then, the line patterns were written
directly inside the photoresist using femtosecond laser induced multiphoton absorption. Here,
we utilized the filamentation of the femtosecond laser pulses in the resist. Finally, thepatterns were transferred to the step structures by CHF3/O2 plasma. The smooth surfaces ofthe structures were successfully obtained, and no crack and thermal damages wereobserved. We also used not only negative-tone resist but also a chemically amplified
positive-tone resist for easier removal of the residual resist after plasma etching process.
Figure 2 shows a silica-based blazed grating, which were created using direct laser writing of
the patterns inside the positive-tone resist. The size and period are 500 um x 500 um and 10
um, respectively. The combination process of femtosecond laser lithography and plasma
etching is useful for fabrication of nonplanar microstructures on inorganic optical materials.

Fig. 1: Silica-based lines on a step
structure

Fig. 2: Silica-based blazed grating
fabricatedusing
positive
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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-13
Femtosecond Laser Direct Writing of Optical Waveguides in
Silicone Film
Susumu Nakamura1, Stephen Ho2, Jianzhao Li2, Shane M. Eaton2,
Haibin Zhang2 and Peter R. Herman2
1

Department of Electrical and Electronic Systems Engineering, Nagaoka College ofTechnology, Nagaoka, Niigata 940-8532, Japan2
Department of Electrical and Computer Engineering, University of Toronto, Toronto,
ON M5S-3G4, Canada
Polymeric optical waveguides have attracted wide interest for potential applications as opticalinterconnects and other micro-optical systems in portable digital equipment and the accessnetwork field. Recently, Okoshi et al. reported direct writing of silica optical waveguides on
the surface of silicone rubber by F2-laser induced photochemical reactions.[1] The high 7.9eV photon energy was instrumental here in transforming silicone into carbon-free silica
waveguides, thereby defining a new means for creating flexible optical circuits. This paper
reports an extension of silicone waveguide formation to nonlinear femtosecond laser direct
writing. An amplified Yb-doped fiber laser (IMRA FCPA μJewel) provided 280-fs pulses at
1044-nm wavelength. Frequency doubling in LBO to 522 nm was used to enhance thenonlinear absorption and potentially drive similar photochemical processes – generation ofO(1D) and silicone photodissociation – as the 157-nm F2 laser. The light was focused (0.55NA aspherical lens) into silicone film (Quantum Silicone, QSIL216), spun uniformly (~30-μm
thick) on a glass substrate. Samples were scanned at variable fluence, focal depth, and scan
speed and then inspected by optical microscopy, SIMMs, and waveguide-firing diagnostics toassess the waveguide formation. We report a permanent modification of refractive index
inside the silicone by the nonlinear femtosecond laser interactions. Single-mode waveguides
were observed at both red (633-nm) and infrared (1560-nm) wavelengths. Figure 1 shows amicroscope image (top) and the near-field mode profile at 1560-nm (bottom) for a 5-μm widesilicone waveguide. This waveguide was formed 6-μm below the silicone surface with 2-nJ
pulse energy and 10^5 overlapping pulses at 1-MHz repetition rate. This paper will present
optimal waveguide processing parameters and assess the underlying photochemical
processes driving the refractive index change. [1]M.Okoshi, J.Li, P.R.Herman: Opt. Lett., 30,
2730(2005)

Fig. 1: Microscope image (top) andnear-field mode profile (bottom) of asilicone waveguide guiding at 1560
nm wavelength light

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-14
Fabrication of a rainbow color logo (diffraction grating) using thepicosecond laser
Jiwhan Noh1 , Hyonkee Sohn1 , Jung Suh1 , Dongsig shin1 , Jae-Hoon Lee1
1

KIMM (Korea Institution of Machinery & Material)

A rainbow color logo mold (diffraction grating) was fabricated by using the picosecond laser.
In this paper, a metallic mold for diffraction gratings was fabricated with a mode-locked 12 ps
Nd:YVO4 laser. Laser pulses with a wavelength of 355nm were irradiated on the surface of
NAK 80, a mold material, to generate line patterns and dot patterns. In order to minimize theline width, laser power was set just above the ablation threshold of NAK 80. The dot patternin the rainbow color logo mold was brighter than the line pattern. Results show that the
spectrum from the fabricated mold was good enough for some industrial application. For themass production, injection molding was performed using the rainbow color logo mold.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-15
InvitedNUV and NIR Femtosecond Laser Modification of PMMA
Alexandra Baum1, Patricia J. Scully1, Walter Perrie2, Martin Sharp2, Ken G. Watkins2,
David Jones3 and Dino Jarozynski3
1

Centre for Instrumentation and Analytical Science, The University of Manchester, M60 1QD,
UK
2
Department of Engineering, The University of Liverpool, L69 7ZG,UK
3
TOPS Facility, Department of Physics, University of Stracthclyde, Glasgow G4 0NG, UK

Significant refractive index changes in clinical grade poly(methyl methacrylate) (PMMA) withboth femtosecond NIR (800 nm) and NUV (387 nm) laser pulses are demonstrated, enablingvolume gratings and waveguides in bulk PMMA. In the NIR, temporal pulse duration isshown to be very critical, with modification efficiency increasing rapidly as pulse duration
decreases below 200 fs. On the other hand, in the NUV, efficient index modification can beaccomplished with longer, 200 fs pulses. The modification of ultra-pure, clinical grade PMMA
demonstrates that doping to increase sensitivity is unnecessary. Grating diffraction efficiency
and refractive index profile measurements infer a maximum positive refractive index changeof Δn(max) = 3x10-3 in exposed regions. Chemical analysis of the modified structures in the
NUV suggests direct polymer back bone cleavage and monomer production as photomodification pathway. Holographic writing at 387 nm with a high NA objective produced weak
periodic features of period Λ= 0.42 μm. The combined results in the NIR and NUVdemonstrate the importance of peak intensity for inducing non-linear absorption andsugggest that three and two photon absorption are responsible for modification of pure
PMMA at 800 nm and 387 nm, respectively.

Fig. 1: Holographically produced submicron structure on stainless stell (left,
SEM picture) and inside PMMA (right,
photograph of white light diffraction)

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-16
InvitedTwo-photon 3D lithography: A versatile fabrication method forcomplex 3D shapes and optical interconnects within the scopeof innovative industrial applications
V. Schmidt1, L. Kuna1, V. Satzinger1, G. Jakopic1, and G. Leising1
1

Institute of Nanostructured Materials and Photonics, Joanneum Research,Franz-Pichler Strasse 30, A-8160 Weiz, Austria

Laser material processing using intense laser pulses, which are provided from ultrafast laser
systems, enable sophisticated structuring methods such as the two-photon 3D lithography.
This method is based on the simultaneous absorption of two photons in a photosensitive
material that is transparent for the laser wavelength. The non linear laser-matter interaction
induces material changes that are tightly confined around the laser focus and build up a
structure in the volume of the material. These intrinsic 3D capabilities allow easy fabricationof a physical structure from a CAD design. In combination with suitable materials, it ispossible to realize complex 3D structures and photonic micro- and nano-systems. We
introduce our experimental setup comprising laser source, three axes sample stage and 3Dregistration of the sample. We present two distinct applications of the versatile two-photon
3D lithography on organic photosensitive materials: first, the fabrication of complex arbitrarily
shaped 3D micro-structures and second, the fabrication of direct laser-written, embedded
multimode waveguides that are aligned relative to preconfigured printed wiring boards(PWBs). In the first case, the high resolution aspect of the method is addressed, while in thelatter case, the lithographic method is combined with astigmatic beam focusing for a larger
interaction volume as required for writing multimode waveguides. Due to the sample
registration prior to the waveguide fabrication, the alignment of the waveguides becomes anintrinsic part of the fabrication process itself. A single organic-inorganic hybrid material isused for both, the waveguide core and its cladding, because the material exhibits asufficiently large increase of the refractive index upon laser irradiation. The function of suchwaveguides is demonstrated (optical loss, etc.). The ultimate goal of this approach is thelarge scale fabrication of leading-edge PWBs with an integrated optical communication layer.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-17
Internal modification of ultra thin silicon wafer by permeable
pulse laser
Etsuji Ohmura1, Masayoshi Kumagai2, Kenshi Fukumitsu2, Koji Kuno2,
Makoto Nakano2 and Hideki Morita2
1

Division of Materials and Manufacturing Science, Osaka University
2
Hamamatsu Photonics K.K.

When a permeable nanosecond pulsed laser is focused into the interior of a silicon wafer andis scanned in the horizontal direction, a belt-shaped high dislocation density layer including apartially polycrystalline region is formed at an arbitrary depth in the wafer. By applying tensilestress perpendicularly to this belt-shaped modified-layer, the silicon wafer can be separated
easily into individual chips without creating any damage to the wafer surface compared to theconventional blade dicing method, because the internal cracks spread from the modified
layer up and down to the surfaces. This technology is called “stealth dicing” (SD), andattracts attention as a novel dicing method in semiconductor industries. The formation
mechanism of this modified layer has been investigated theoretically for a relatively thickwafer in previous studies and it has been concluded that the modified layer and the internalcracks are generated due to propagation of a thermal shock wave caused by laser
absorption. In this study, SD was applied to ultra thin wafers 50 um in thickness (Fig. 1). A
coupling problem composed of focused laser propagation in single crystal silicon, along withlaser absorption, temperature rise and heat conduction was analyzed by considering thetemperature dependence of the absorption coefficient as in our previous studies. When thedepth of the focal plane is too shallow, the laser is also absorbed at the surface as thethermal shock wave reaches the surface. As a result, not only is an internal modified layer
generated but ablation occurs at the surface as well (Fig. 2(b)). When the laser is focused at
the surface, strong ablation occurs (Fig. 2(c)). Ablation at the surface is unfavorable becauseof the debris pollution and thermal effect on the device domain. It was concluded that there isa suitable depth for the focal plane so that the thermal shock wave propagates inside thewafer only (Fig. 2(a)).

Fig. 1: Stealth dicing of silicon waferof 50 µm thickFig. 2: Maximum temperature
distribution
during one pulse irradiation of 1064 nm laser to asilicon wafer of 50 µm thick. Contour lines show 500,
700, 1000, 1500, 2000, 3000, 5000, 7000 and 10000
K (pulse energy 2.74 µJ, pulse width 150 µs, spot
radius 485 µm)

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24-28 April 2007, University of Vienna, Vienna, Austria

Th S2-18
TEM observation of structural changes under 4H-SiC single
crystal surface irradiated by femtosecond laser pulses
Tatsuya Okada 1, Hiroyuki Kawahara 1, Ryota Kumai 2, Takuro Tomita 2, Shigeki Matsuo 2,
Shuichi Hashimoto 2 and Makoto Yamaguchi 3
1

Department of Mechanical Engineering, The University of Tokushima,
2-1 Minamijosanjima, Tokushima 770-8506, Japan,
2
Department of Ecosystem Engineering, The University of Tokushima,
2-1 Minamijosanjima, Tokushima 770-8506, Japan,
3
Technical Research Institute JAPAN Society for The Promotion of Machine Industry,
Higashi-Kurume, Tokyo 203-0042, Japan

A number of studies have been conducted on the formation of laser-induced ripple structureson the semiconductor surface irradiated by femtosecond laser pulses because the ripple
structures may be applied to nano-scale surface machining. The purpose of the present
study was to examine the cross-sections of fine and coarse ripples formed on 4H-SiC single
crystals by transmission electron microscopy (TEM). Femtosecond laser pulses were
irradiated onto the (0001) surface of 4H-SiC single crystals to form ripple structures. The
wavelength, energy, width and number of pulses were 800 nm, 6 microJ/pulse, 130 fs and 50
shots, respectively. Cross-sectional TEM samples perpendicular to the ripples were preparedby focused ion beam (FIB) micromachining. Cross-sectional TEM images for fine and coarse
ripples are presented in Fig. (a) and (b), respectively. The dark area in the micrographs is thetungsten layer deposited on the surface prior to the FIB machining. The periods of fine andcoarse ripples are about 200 nm and 500 nm, respectively. Although the morphology istotally different, microstructural features are similar. Along the surface undulation, there
exists a thin layer approximately of 50 nm. Probably, this topmost layer corresponds toamorphous detected by micro Raman spectroscopy.[1] Beneath the topmost layer, anotherthin layer appears dark. This second layer is accompanied by strain because its appearancechanges with the diffraction vector g. In some areas, we observed crystallographic defects
such as dislocations and stacking faults introduced by the strain. Such defects did not
penetrate the topmost layer because the layer was not crystalline. So far, we found that the
microstructural features are common to any ripple structures irrespective of their morphology.
This suggests that the formation mechanisms are also common for both fine and coarse
ripples.
[1] M. Yamaguchi et al.: Proc. of 4th Int. Cong. on Laser Advanced Materials, p.117, Kyoto,
2006.

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Special Session 3 (LPM-S-3):

Advanced Laser Systems and Optics(New Laser concepts and beam delivery systems, etc.)
Session Organizers:
Eric Fogarassy (Ecole nationale supérieure de physique de Strasbourg, France),
Tino Petsch (3D-Micromac AG, Germany), Andreas Stingl (Femtolasers Produktions
GmbH, Austria)

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-01
InvitedOptical lithography for photonic band gap materials
Sajeev John1
1

University of Toronto,

Photonic band gap (PBG) materials are three-dimensional (3D) periodic microsctructuresthat enable the localization of light. These materials and their 2D counterparts haveapplications to optical information processing, lighting, energy conversion, optical sensing,and clinical edicine. In the past, it has been considered very challenging to micro-fabricate
3D PBG materials, out of high refractive index materials such as silicon, with diamond crystal
symmetry, for guiding and trapping light in the near-infrared to visible wavelength regimes.
This situation is now changing as a result of optical lithography methods. I describe thedevelopment of optical phase mask architectures capable of creating diamond-symmetry
PBG architectures based on illumiation by a single laser beam. This is a significant
simplification to previously proposed methods based on multi-beam optical interference. The
optical phase mask method may be combined with direct laser writing techniques andphotoresist-to-silicon replication methods to create circuits for light on a 3D optical microchip.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-02
Grating interferometers for efficient generation of large area
grating structures via laser ablation
J. Bekesi1, J. Meinertz1, J. Ihlemann1, and P. Simon1
1

Laser-Laboratorium Göttingen e.V., Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany

Generation of large area grating structures by laser ablation is a challenging task if the wholearea must be patterned with a high definition submicron-period line structure in perfectregistry. A Two-Grating-Interferometer set up is described for producing large area grating
structures via laser ablation with UV pulses. Phase grating pairs on fused silica substrates
with high damage threshold and diffraction efficiency were illuminated with non-collimated(convergent) laser beams to generate a periodic intensity distribution with high energy
density and high contrast on the sample surface. Large line numbers without phase
distortions were reached by applying cylindrical focusing perpendicular to the plane ofdiffraction. Scanning with the illuminating laser beam in the direction parallel to the gratinglines enabled the fabrication of cm-scale grating size with multiple shot ablation, while
keeping the whole line structure in phase. Complex patterns are possible by applying
multiple exposures. Experimental results demonstrating the capability of the method togenerate laser ablated grating structures with submicron periods down to ~300 nm arepresented.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-03
Fabrication of Nd:Gd3Ga5O12 planar waveguide laser by pulsed
laser radiation
Dimitri Ganser1, Herbert Horn-Solle1, Leonid Moiseev1, Larisa Starovoytova1, Ion Vasilief1,
Dirk Wortmann1, Jens Gottmann1
1

Lehrstuhl für Lasertechnik, RWTH Aachen, Steinbachstr. 15, 52074 Aachen, Germany

Pulsed laser radiation is used as well for the deposition of the laser active thin films of
Nd:Gd3Ga5O12 as for micro structuring to define wave guiding structures for fabrication of awaveguide laser. Laser active films with thickness up to 5 µm of Nd:Gd3Ga5O12 on YAG(Y3Al5O12) and sapphire single crystalline substrate are fabricated by pulsed laser
deposition using a KrF eximer laser (μ = 248 nm, τ = 25 ns). By variation of PLD-parameterssuch as temperature and pressure of processing gas amorphous and single crystaline thinfilms are produced. X-ray diffraction using θ-2θ scans in Bragg geometry with Cu kα radiation(μ = 0,15406 nm) is used to determine the structural properties of the deposited films. By
coupling the radiation of a diode laser (μ = 808 nm) into the polished edge of the film theoptical properties of the films are determined. The emission spectrum of an amorphous filmis broadened inhomogeneously and the spectrum of a crystalline film is similar to that of thebulk Nd:GGG crystal used as a target material for the deposition. A planar wave guiding
structure is generated between two parallel grooves micromachined using laser radiationfrom a femtosecond CPA-Laser-System with μ = 800 nm and pulse duration of 100 fs. The
structural properties on the films and the extinction losses of the structured waveguide aredetermined. For the first time a structured planar waveguide laser of an amorphous
Nd:Gd3Ga5O12 thin film on YAG (Y3Al5O12) single crystalline substrate is achieved.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-04
Trouble shooting and optimization of laser beam parameters for
precision micro fabrication by beam analysis
O. Märten1, V. Brandl1, R. Kramer1, H. Schwede1, S. Wolf1
1

PRIMES GmbH, Max-Planck-Str. 2, 64319 Pfungstadt

Precision laser micro fabrication processes have strong requirements on beam parameters in
the focus because of their influence on processing speed and quality, e.g. drilling speed andhole geometry, cutting speed and kerf shape, milling speed and contour accuracy as well as
surface roughness. These beam properties are not only determined by the power density
distribution at the laser but also by the propagation properties of the beam as well as by the
optical performance and quality of the beam train and focusing system. (e.g. telescopes,
polarization filters, attenuators, masks, diffractive beam shapers, lens systems, etc.) Focus
analysis at real process conditions reveals the resulting beam parameters of the spot: beam
shape in the focus, focus diameter, Rayleigh length, beam propagation ratio, focus position,and far field divergence. In the case that the measured focus parameters differ from thespecs, the causes for deviations have to be identified. Effects from laser, beam train, andfocusing system have to be distinguished. Here beam propagation analysis at different
positions in the beam path is required. We will show the influence of optical component
properties and alignment on beam propagation and beam parameters in the focus.
Furthermore we will demonstrate methods for the optimization of beam parameters using
beam propagation analyzers and focus analyzers.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-05
In-process monitoring and adaptive control during micro
welding with CW fiber laser
Yousuke Kawahito1, Masaharu Kawasaki1 and Seiji Katayama1
1

Joining and Welding Research Institute (JWRI), Osaka University

Fiber laser has an excellent beam quality enough to be applied for micro welding ofelectronics or automobile parts, and thus is regarded as a promising heat source for adaptive
control since the laser peak power can be changed within sub-micro-second period. Laser
micro welding of sheets can be influenced by the surrounding heat transfer conditions. This
study was therefore undertaken with the objective of developing a new laser system with inprocess monitoring and adaptive control for the stable production of sound welds in thinsheets. The bead-on–plate welding of 0.1 mm-thick stainless steels was performed with a 75
W fiber laser beam of 1,090 nm in wavelength. The stability of bead widths of laser welds
made with or without monitoring and adaptive control was investigated in welding the sheetwith or without heat exchanger plate. It was revealed that the heat radiation signal was
sensitive to the increase in the bead width when the heat transfer process was changed tothe heat-insulated process. Moreover, the peak power was controlled in the minimum 50 msshort period in order to produce stable weld bead width regardless of the existence of theheat transfer plate, and the limit cycle time of the adaptive control was investigated bycomparison with the bead widths of welds made without adaptive control. It wasconsequently confirmed that the fiber laser was an excellent oscillator for the adaptive control
in laser micro welding.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-06
TRUMPF Disklaser, TruDisk
S. Weiler1, Brockmann1
1

TRUMPF Laser GmbH + Co. KG, Aichhalder Strasse 39, 78713 Schramberg, Germany

Todays development of new laser beam sources is dominated by the new generation ofdiode pumped solid state lasers. The TRUMPF disk laser offers a unique variety of features,
which assure the success of industrial applications. The power range from several hundred
watts up to 8 kW enables both, micro material processing as well as welding of thick metal
sheets.
Actual applications of the TRUMPF disklaser vary from welding and remote scanner welding
to cutting, ablation and structuring of surfaces. The beam quality and output power of the
TRUMPF disklasers are geared to its application, whereat no limits are reached today. The
potential of the TRUMPF disk technology was demonstrated in several prototypes, where 25
kW output power or a beam quality of 4.5 mm*mrad @ 5 kW were provided. Furthermore,
the potential of cost reduction will be successively opened up. The price per kW was reduced
to a level of 60% within the last three years, and will be reduced further on in the next years.
By these means the cost-effectiveness of laser processes is increased and new applications
will be established.
The presentation will show the design of the TRUMPF disklaser, gives an overview of actual
industrial applications and will point out future developments in technology and cost.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-07
Ablative laser micro processing with short and ultrashort pulses
S. Weiler1, J. Stollhof1, D. Eckert1, J. Kleinbauer1, D. H. Sutter1, M. Kumkar1
1

TRUMPF Laser GmbH + Co. KG, Aichhalder Strasse 39, 78713 Schramberg, Germany

Ablative laser-micro-processing can be achieved by using a wide range of pulse durations.
The demands on quality and throughput do vary when the pulse duration changes from lowµs over several tens of ns to the < 10 ps range. Micro-machining with short ns-pulses has
become well established and widespread for industrial usage. TRUMPF Laser has
developed advanced solid-state q-switched lasers, designed to specifically meet therequirements of industrial micro-processing. If short is not short enough, i.e. no mechanicaland thermal modification of the surrounding material is required (cool processing), then thelaser-material-interaction-time has to be reduced by shortening the pulse duration. Due to thefact that cool material processing is still possible by using ps pulses, the technologicalapproach to create these pulses can be dramatically simplified. We present a CPA-free,
diode-pumped all-solid-state laser, delivering pulses as short as 6 ps with an average powerof 50 W at a repetition rate of 200 kHz. The corresponding pulse energy of up to 250 µJ
provides the basis for efficient material-processing. Precise switching or attenuation of theamplified pulses is provided by an external modulator. The laser output beam is diffraction
limited, with an M² < 1.2 and a roundness of > 95 %. If burr formation and heat affected zone
are acceptable or the material properties (melting temperature, vaporization temperature andthermal conductivity) allow for it, then the productivity of the laser ablation process can be
maximized by turning to longer (several hundreds of nanoseconds to one microsecond)
pulse durations. Here the free space beam delivery, a drawback of the ns and ps lasers, canbe overcome by fiber coupling. Using the q-switched disk-technology, pulse durations in theorder of 1 µs with an average power of 400 W at a repetition rate of up to 20 kHz can berealized. The beam delivery is implemented by a step index fiber.

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24-28 April 2007, University of Vienna, Vienna, Austria

We S3-08
Millijoule high-repetition rate femtosecond laser amplifier
Martin Delaigue 1, Clemens Hönninger 1, Antoine Courjaud 1, Eric Mottay 1,
Inka Manek-Hönninger 2
1

2

Amplitude-Systèmes, 6 allée du doyen Georges Brus, 33600 Pessac, FranceCentre Lasers Intenses et Applications, Université Bordeaux 1, 351 cours de la Libération,
33405 Talence, France

We demonstrate millijoule-level pulse energy extraction from a high-repetition rate diodepumped Ytterbium-doped femtosecond laser amplifier. The extracted pulse energy exceeds
1 mJ for pulse repetition rates up to 5 kHz and remains above 0.1 mJ for repetition rates ashigh as 100 kHz. In order to minimize nonlinear effects and avoid damage to opticalcomponents, we applied chirped pulse amplification using a grating-based stretcher prior toamplification and a grating-pair com-pressor. After compression we measured a pulse
duration of 480 fs. The M² value was better than 1.2. These parameters result in a versatilehigh-energy laser source that can be operated in a wide range of pulse repetition rates
matching the requirements of numerous high precision machining ap-plications. The
complete laser system fits into a compact footprint of 750x500 mm².

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24-28 April 2007, University of Vienna, Vienna, Austria

Fr S3-09
InvitedFiber lasers and amplifiers:
Novel avenues to real world applications of ultrashort lasers
Andreas Tuennermann1, Jens Limpert1, Stefan Nolte1
1Friedrich-Schiller-University Jena Fraunhofer Institute forApplied Optics and Precision Engineering

Fiber lasers and amplifiers: Novel avenues to real world applications of ultrashort lasers
Rare-earth-doped fiber lasers are one of the most promising solid-state laser concepts due tothe outstanding thermo-optical properties of an actively doped fiber. The large ratio of
surface to active volume of such a fiber ensures excellent heat dissipation, furthermore thebeam quality is defined by the refractive index profile of the active core and is therefore
independent on the pump power. Fiber lasers and amplifiers offer a very high single-passgain and therefore low laser thresholds and efficient diode-pumped operation approaching
the kW-level based on the double-clad design. Ytterbium-doped fibers provide also several
key advantages regarding the amplification of short optical pulses. The gain bandwidth
supports pulses as short as ~30 fs, the huge saturation fluence allows for the generation of
millijoule pulses and high optical pumping efficiencies (up to 80%) even for ns-pulses, makean ytterbium-doped fiber amplifier to an outstanding gain medium. However, power andenergy scaling of ultrafast single-mode fiber amplifiers is restricted due to nonlinear pulse
distortions, which are enforced by the large product of intensity and interaction length inside
the fiber core. This limitation can be overcome by sufficient pulse stretching in the time
domain and the enlargement of the mode-field diameter of the fiber to reduce the nonlinear
effects such as stimulated Raman scattering (SRS) and self-phase modulation (SPM). The
application of this technique leads to a chirped-pulse amplification (CPA) system based onlarge-mode-area fibers (LMA), where power scaling is limited by the maximum acceptablephase distortion due to self-phase modulation. An ytterbium-doped ultrafast fiber CPA
system what generates 100 µJ pulses at repetition rates above 100 kHz is reported. The
application of this system in advanced laser micro-machining of metals and semiconductors
is discussed.

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Fr S3-10
Fundamental and beam propagation behavior of a microjet® andrecent applications using laser microJet technology
Dr. Tuan Anh Mai1, Dr. Bernold Richerzhagen1
Synova SA

The innovative water jet-guided laser technology (also called as Laser MicroJet® LMJ) isrelatively new. However, due to a number of unique advantages, it has quickly andsuccessfully matured into many applications such as dicing and slotting of silicon wafers,
cutting of coronary stents, drilling of stencil and OLED masks, as well as the cutting of hardmaterials for tool inserts. This cold, clean machining technology allows the precision
fabrication of intricate structures, providing exceptional aspect ratios. In this paper, thefundamental behavior of a hair-thin water jet such as jet velocity, jet breakup andinterruptions are studied. A well-rounded understanding of the jet stability characteristics isvery important to enhance the performance of the LMJ technology. The propagation and theintensity distribution of a laser beam coupled in the low pressure, laminar water jet at various
coupling conditions are theoretically and experimentally investigated as well. The final part ofthis paper will highlight some recent micromachining examples of the LMJ technology.

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Fr S3-11
On the mechanism of laser-matter interaction in laser drillingand spot welding
Wm. R. Harp1, S. Noguchi1, J. Tu1, E. Ohmura1
Dept. of Mechanical and Aerospace Engineering, North Carolina State University,
Raleigh, NC, USA, 27695 Division of Materials and Manufacturing Science, Osaka
University, Osaka, JapanThe mechanism of laser ablation is investigated both experimentally and theoretically for
microsecond laser ablation using a 300W, single-mode CW fiber laser. Pulses of 1
microsecond and longer are used to achieve laser ablation and those longer than 100
microseconds are used to produce spot welding. Control methods are developed to exploit
the use of an initial spike of about 1.5 kW in power that lasts approximately 1 microsecond
and then falls to its steady output level at 300 W. The laser can then be controlled togenerate a pulse duration between 1 microsecond to 1 ms. Experimental results, based onhigh speed photography, in-process plasma measurements, and cross-section etching,reveal that, for a 1 microsecond pulse, the primary mechanism of ablation is seen to beevaporation with a small amount of melt ejection. For longer pulse durations, the lower
steady state power contributes only to further heating and melting of the material to widen
the molten pool. There is experimental evidence of boiling that occurs in the melt pool for
long pulse up to 1 ms. These experimental results are used to refine a theoretical model
which simulates details of the keyhole creation at the beginning of the pulse and the keyhole
collapsing at the end of the pulse. The simulation results show that the laser beam is mainly
absorbed via multiple reflections of the laser and as the keyhole depth increases, absorption
in the bottom of the keyhole increases, providing the energy for the boiling mechanism seenin the experimental investigation. At the end of a long pulse, spot welding is formed because
the keyhole collapses quickly by the surrounding large molten pool. The melt quickly fills the
keyhole and solidifies to form a bump on the surface with either large or very fine voids
inside.

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Session 4 (LPM-4):

Micromachining and Processing

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Tu 4-01
InvitedAdvanced double pulse format for increasing the speed andquality of high aspect ratio laser micromachining
A. Forsman1, A. Dodell1, M. Armas1, E. Lundgren1, A. M. Komashko1
1

General Atomics, P. O. Box 85608, San Diego, California 92126-5608, USA

The speed and quality of laser machining has been improved by using a train of pairs of 4 ns
laser pulses rather than a train of single laser pulses. The first laser pulse in each pairgenerates an ablation plasma and other ablation debris which is allowed to dissipate for aprescribed period of time. After the debris has partially dissipated the second pulse of thepair strikes, and heats the remaining debris to cause more efficient ablation and inhibit
redeposition. The use of pairs of laser pulses therefore uses debris and plasma to enhancemachining performance. Material removal rates have been significantly improved, by factorsof three to ten times while reducing redeposition and reducing or eliminating heat affected
zones. Percussion drilling using this double pulse format has also been used to produce
small (< 10 um diameter), high aspect ratio (> 30:1) holes that are straight and reproducible.
In addition to improvements in machining speed and quality, measurements of the lasertarget interaction and results of numerical modeling will be presented. These, together withthe results of laser machining trials, are used to develop a phenomenological model toaccount for the improvements in performance that are offered by the double pulse format.

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Tu 4-02
Nonlinear Nd:YAG laser-induced optical blooming of glassceramics
V.P. Veiko1, B.Yu. Novikov1
1

St.Petersburg State University of Information Technologies, Mechanics and Optics

There are class of glass-ceramics (GC) materials which are not transparent in a visible range
due to a high light scattering by their polycristalline structure. Laser action can localy modify
crystalline phase of those materials to the amorphous. Usually a popular laser for such kindof transformations is a CO2-laser (10.6 mkm). As initial (crystalline) as final (amorphous)
phase have a strong absorption in a middle infrared (IR) range. Different situation have placewhen near-IR radiation acts on to these matereals. From one hand absorption of initial GC in
this case is little bit less but enough to lead to laser melting followed by hardening and finallyto amorphization of initial structure. From the other hand amorphous GC is a kind of glass
which is highly transparent for near IR-radiation. This phenomenon produce new situation
which we call as nonlinear optical blooming. Optical blooming has been investigated in thiswork on the example of ST-50 GC experimentally and theoretically. Some examples of
Nd:YAG-laser (1.06 mkm) amorphization of ST-50 GC for different applications aredemonstrated. Nd:YAG-laser provides smaller size (higher resolution) and bigger deepnessof bloomed area than CO2-laser.

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Tu 4-03
Fabrication of an OLED display using an ultra-short fiber laser
ITO Yoshiro1, ONODERA Yousuke1, TANABE Rie1, ICHIHARA Masahiro2 and KAMADA
Hideki2
1

Department of Mechanical Engineering, Nagaoka University of Technology,1603-1,Kamitomioka, Nagaoka, Niigata 940-2188
2
R&D Center, Tokki Co., 10-1, Sinko-cho, Mitsuke, Niigata 954-0076

Organic light emitting diode (OLED) is now in practical use and also a subject of active
research and development. In industrial production of OLED displays, one of the key
technologies is patterning of electrodes, especially a metal electrode, which is usually madeon a thin layer of organic compounds. Laser machining of the electrode is one of the possible
techniques. We have developed a selective patterning technique of a thin top electrode ofaluminum using an ultra-short fiber laser. OLED sample used has indium tin oxide (ITO)
anode of about 150 nm thick at the bottom. The organic electro-luminescence material ofless than 200 nm is deposited on it and the top is aluminum cathode of 100 to 150 nm
thickness. An ultra-short fiber laser at 1560 nm with a repetition rate of 198 kHz is used tothe patterning of the aluminum electrode and a display panel of the OLED is fabricatedsuccessfully. Benefits of our system will be described. It is found that the underlying layers
affect much to the machinability of top metal electrode. The ITO layer seems to enhance themachining efficiencies of aluminum electrode. Its machining threshold fluence becomes
lower and the ablated size becomes larger for that on ITO than that without ITO, even though
the laser energy is kept constant. These phenomena cause some difficulties in the laser
fabrication process of the OLED. To investigate the phenomena in detail, we haveconstructed two ultra-fast imaging systems using an ultra-fast Ti:Sapphire laser at 785 nmwith 1 kHz repetition rate, one of which has a time-resolution of one picosecond and theother has five nanoseconds, and carried out time-resolved imaging observations of theprocess. Even though we use two different types of lasers as machining tools, the observed
effects of ITO layer seems quite parallel. The results suggest that the change of thethreshold energy might be due to the change of relevant machining mechanisms.

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24-28 April 2007, University of Vienna, Vienna, Austria

Tu 4-04
Electronic properties of thin polymer films deposited byresonant infrared laser ablation
R. F. Haglund1, Jr. S. L. Johnson1 and H. K. Park1
1

Vanderbilt University AppliFlex LLC

Current liquid-phase techniques for fabricating polymer-based electro-optic devices — e.g.,
ink-jet deposition, spin coating — face significant challenges of material deposition efficiency,
solvent bleedthrough and decomposition, and lifetime degradation due to electro-chemical
activity. While resonant infrared pulsed laser deposition (RIR-PLD) has been successfully
used to deposit many different kinds of polymers, maintaining electro-optic functionality fromdevice-compatible polymers such as MEH-PPV and PEDOT:PSS has proven to be astringent test of this process. We have recently been able to deposit both conductive andelectro-luminescent polymers by RIR-PLD, in some cases using matrix- or co-matrix-assisted
ablation, and have compared the electronic properties of the RIR-PLD films with thoseobtained by conventional spin coating. In this paper, we present results of these experiments
on both PEDOT:PSS and MEH-PPV thin films, including transport measurements bystandard four-point probe techniques, and spectral characterization of electroluminescenceand photoluminescence. The results suggest that the polymer films prepared by RIR-PLD
exhibit a level of performance compatible with device requirements for electro-optic
applications, such as organic light- emitting diodes. By correlating these measures of theelectronic properties of the film with variations in the operating parameters of a picosecond,
tunable free-electron laser (FEL), we are able to identify specific effects of laser fluence andwavelength on the electronic properties of the deposited films. These comparative studies
are providing new insights into the mechanism of infrared laser ablation of intact polymers in
the regime of picosecond pulses and very high pulse-repetition frequencies. We will also
discuss the potential for the use of more conventional laser systems, such as amplified,
frequency-shifted ultrafast solid-state lasers, to reproduce these results.

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Th 4-05
InvitedA Experimental Study on Raising the Efficiency of Production for
Industrial SFF system
Dong Soo Kim1, Sung Woo Bae2 and Kyung Hyun Choi3
1,2

IT Machinery Research Center, Korea Institute of Machinery & Materials, Daejeon, Korea.
3
Cheju National University, Cheju, Korea

A Solid Freefrom Fabrication (SFF) system using selective laser sintering (SLS) is currently
recognized as a leading process and SLS extends the applications to machinery andautomobiles due to the various materials employed. Especially, accuracy and processing
time are very important factors when the desired shape is fabricatied with selective laser
sintering (SLS), one of Solid Freeform Fabrication (SFF) system. In the converntional SLS
process, laser spot size is fixed during laser exposing on the sliced figure. Therefore, it isdifficult to accuracy and rapidly fabricate the desired shape. In this paper, to deal with those
problems a SFF system having abilty of changing spot size is developed. The systemprovides high accuracy and optimal processing time. Specifically, a variable beam expander
is employed to adjust spot size for different figures on a sliced shape. Finally, design andperformance estimation of the SFF system empoying a variable beam expander areachieved and the mechanism will be addressed to measure the real spot size generated fromthe variable beam expander.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 4-06"Dry-Etching System" with Q-switched DPSS laser for flat panel
displays
Naoaki Fukuda1, Kazuyoshi Kunishio1, Shigeaki Nakayama1
Hitachi Zosen Corporation

Flat panel displays (FPDs) are used in many electrical products, such as cellular phones,
car-navigation systems, personal computers, slim profile televisions and so on. With the
popularization of these productions, the market of FPDs has expanded rapidly. The current
industry trends for FPD productions are: increase in picture quality and multifunction
capabilities. Other factor also includes pursuit of the cost reduction, environmental
conservation and so on. An etching process of thin film for FPDs is usually performed by a
wet etching method. By replacing the wet etching method with the laser-dry-etching method,
there is an enormous cost reduction. And the product is made under a clean and chemicalfree manufacturing environment. Moreover, the laser-dry-etching method can exchange
product patterns quickly. This method has attracted a great deal of interest in industry
because it has many potential benefits. The laser-dry-etching for FPDs have the ability toprocess large areas with minute detail and at high speed. However, the laser-dry-etching
method requires that a large amount of energy to be concentrated for small areas. Therefore,
it takes a long time to process a large area due to lack of energy source. A sufficient power isneedful to process a huge area on a large-scale substrate. On the other hand, it is clear thatthe laser beam with huge power oscillators is more unstable and produce lower quality
results because of thermal lens effect and lens degradation. Moreover, it is crucial to keep
making high-quality processing, in the mass production lines, which operate 7 days per
week, 24 hours per day. The authors have developing various laser-dry-etching system forlarge-scale FPDs. All these system tries to balance between processing speed to processing
quality. In this paper, these needed elements for the FPD manufacturing are discussed.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 4-07
UV laser microprocessing of photovoltaic devices based on thinfilm a-Si:H
C. Molpeceres1, S. Lauzurica1, J.J. García-Ballesteros1, S. Fernández-Robledo1,
M. Morales1, J.L. Ocaña1, J.J. Gandía2, J. Cárabe2
1

Centro Láser UPM. Univ. Politécnica de Madrid. Crta. de Valencia Km 7,3.
28031. Madrid. Spain.
2
Dept. de Energías Renovables. Energía Solar Fotovoltaica. CIEMAT. Avda. Complutense,
22. 28040. Madrid. Spain.
Laser ablation of individual layers in Glass/TCO/Thin-film silicon/Metal structures is essential
for cell isolation and monolithic interconnection in thin-film photovoltaic technologies. In theseprocesses laser technology appears as a very competitive alternative both in quality andrunning costs and, taking into account the importance of controlled material removal process
in photovoltaic industry, is remarkable the scarce academic research in this field. On theother hand, suppliers of laser machinery have been working in the development of potential
applications of this technology for film ablation and patterning during years, obtaining
promising results using excimer lasers for annealing and ablation, and excellent results withsolid state pulsed lasers sources for direct writing and backscribing techniques in cells andmodules production. More recently, the potential application of laser scribing techniques forthe development of photovoltaic matrix position sensors based on a-Si has generated much
activity. This work gives an approach to the characterization of ablation process in thin film aSi based devices using ns laser sources, determining potential parametric windows and an
giving an approach to the quality assessment based on the morphological analysis of thegenerated tracks. The study is focussed on direct writing techniques using UV sources,
taking into account that backscribing techniques at 532 nm are well developed and are fully
integrated in industrial production. Moreover only laser sources in the ns regime has been
considered, bearing in mind that thin film based photovoltaic technologies are still demanding
further reduction in production costs and, nowadays, ultrafast sources are beyond the scopeof these technologies due to their investment and running costs. ACKNOWLEDGMENTS:
Work financed by the Spanish National R&D Plan Ref. NTS (ENE2004-07376-C03)

Fig. 1: LSCM profiles and SEM images(x1.5k) of ablated a-Si under
different irradiation condition
at 248 nm. SEM images havebeen sized in order to fit
groove width in measured
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24-28 April 2007, University of Vienna, Vienna, Austria

Th 4-08
Selective laser ablation of photoresists for MEMS devices
S. Zoppel1,2, S. Partel2, J. Zehetner2, P. Hudek2, G.A. Reider2
1

Vienna University of Technology, Photonics Institute,Gusshausstr. 27-29, 1040 Vienna, Austria
2
Vorarlberg University of Applied Sciences, Research Center for Microtechnology,
Hochschulstr. 1, 6850 Dornbirn, Austria

We present recent results on selective laser ablation of thick photoresists (KMPR, SU-8, AZTypes) from dielectric and metallic substrates as a process step in MEMS fabrication,
capitalizing on different ablation mechanisms with ultrashort pulsed Yb:Glass and CO2 laser
systems, respectively. By employing pulses with a duration of 300 fs we were able tostructure thick photoresist selectively on a glass wafer without damaging the substrate.
Subsequent sputter and micro-electroplating steps permit the fabrication of metallic
structures of micrometer size. The removal of the remaining photoresist was performed byquasi-cw CO2 laser radiation. While femtosecond pulse durations permit structuring almost
free of any heat load to the material, the thermal nature of the CO2-laser ablation ofpolymers is well suited for resist removal. In particular, thick resists like KMPR or SU-8 used
for UV-LIGA can be removed from high-aspect ratio structures by solvents only with difficulty.
The CO2 radiation at 10.6 microns is highly absorbed by the polymer material, yetcompletely reflected by the subjacent sputter layer. Although this method does not allow
process speeds comparable to conventional lithography, it is a valuable and highly versatile(because maskless) option as for rapid prototyping in R&D.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 4-09
Rapidly tunable Bessel beam and pattern generation for laser
microprocessing
Euan McLeod1 and Craig B. Arnold1
1

Department of Mechanical and Aerospace Engineering Princeton University

Rapid shaping of an incident Gaussian laser beam enables local control and spot-to-spot
modifications over material properties in pulsed and CW applications. In this study, we
present a novel approach to beam shaping and Bessel beam formation using a Tunable
Acoustic Gradient Index of Refraction (TAG) lens. Bessel beams have the unique properties
of nondiffracting and self-healing behavior with a characteristically different intensity profile
compared to a focused Gaussian. These features can be beneficial in a variety of laser
processing applications such as deep hole drilling, waveguide fabrication, micromachining on
non-planar substrates and 3-d manufacturing. Bessel beams are typically created usingaxicons, diffractive elements, or holographic methods all of which present fundamental
limitations to high throughput, tunable operation. In our approach, an amplified ultrasonicsignal is used to establish a steady-state density fluctuation within a liquid causing anoscillatory variation in local index of refraction. Light propagating through this liquid produces
a Bessel-like beam whose properties primarily depend on driving amplitude, frequency,
geometry and liquid properties. The theory behind the lens operation, its degrees of control,
experimental results, and applicability to laser-materials processing will be presented.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 4-10Laser induced foaming and chemical modifications of gelatine
films
Gaspard S. 1, Oujja M. 1, Abrusci C. 2, Catalina F. 3, Lazare S. 4,
Desvergne J-P. 5, Castillejo M. 1.
1

Institute of Physical Chemistry, CSIC, Madrid, Spain.
Department of Physical Chemistry, Faculty of Chemistry,
Universidad Complutense de Madrid, Madrid, Spain.
3
Institute of Polymer Science and Technology, CSIC, Madrid, Spain.
4
LPCM, CNRS UMR 5803, Université de Bordeaux 1, Talence, France.
5
LCOO, CNRS UMR 5802, Université de Bordeaux 1, Talence, France.
2

This paper investigates the microfoaming [1, 2] and accompanying chemical modifications
following single pulse laser irradiation at 248 nm (KrF excimer laser, 20 ns fwhm) and at 266
and 355 nm (Nd:YAG laser 4th and 3rd harmonic, 6 ns fwhm) of films of gelatine. It was
earlier anticipated that the foaming mechanism can be viewed as a cold boiling phenomena
mainly induced by the laser launched tensile wave at the film surface. Therefore
spectroscopic investigations are expected to confirm that the material does not degrade
because of a high temperature. Fluorescence emissions from the films were studied byspectrofluorimetry and laser induced fluorescence and the emission lifetimes were measured
by time-correlated single photon counting. This approach opens up the possibility to gain
information on the molecular structure of the new nano-foamy material, as well as on its
microscopic distribution with emerging fluorescence-based confocal systems allowing highspatial resolution. The main fluorofores responsible of the observed emissions are aromatic
aminoacids like tyrosine and its derived crosslink products, possibly formed during the laser
foaming. It is observed that laser irradiation with a single ns UV pulse induces modifications
on the relative intensity of emisions depending on the wavelength of irradiation and the typeof film. The observed chemical changes are related /discussed in terms of the structuralmodifications induced by foaming and have important consequences for the laser processingof biopolymers of interest in biomedical applications since the obtained laser foam exhibitsinteresting properties close to that of the natural extracellular matrix ones.
[1] S.Lazare, V.Tokarev, A.Sionkowska, M.Wisniewski Appl.Phys.A: 81(2005) 465 andJ.Phys.D:Conf.Ser.,(in press).
[2] M.Oujja, E.Rebollar, C.Abrusci, A.Del Amo, F.Catalina, M.Castillejo:
J.Phys.D:Conf.Ser.(in press).

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Th 4-11Fabrication of surface-enhanced raman scattering substrate on
ag-doped silicate glass using femtosecond laser
Zenghui Zhou1, Jian Xu1, Ya Cheng1, Guiying Wang1, and Zhizhan Xu1
1

The State Key Laboratory of High Field Physics, Shanghai Institute of Optics and Fine
Mechanics, Chinese Academy of Science, Shanghai, 201800, China

Detecting molecules in solution with high sensitivity and molecular specificity is of greatscientific and practical interest in many fields. Raman spectra, which can provide a structural“fingerprint” of the molecules, can be enhanced greatly by surface-enhanced Raman
scattering (SERS) for the detected molecules close to metal nanoparticles, which makes
itself an important tool in the biomedical detection. In this paper, we report the fabrication of a
new kind of substrate on Ag-doped glass for SERS using ultrashort pulse laser. Silver
nanoparticles are formed in the fs laser scanned areas by electroless plating the laserirradiated sample in the solution of AgNO3 at proper temperature. After this, a rough silver
film is deposited on the glass which can be used for SERS. The normal and SERS spectra ofglycine are detected individually. The results compared in Fig.1 clearly show the enhanced
Raman signal measured on the substrate deposited with silver-nanoparticles. The
enhancement factor of this substrate for glycine is about 2500 in our experiment. The
enhancement factor may be improved further for the polar molecules which can be absorbed
more close to the substrate. Furthermore, the substrate fabricated by the ultrashort pulse
laser scanning followed by the electroless plating makes it possible to construct SERS-based
microsensor inside a microfluidic channel because the fabrication of embedded microfluidic
hollow structures in Foturan glass has already been demonstrated so far. Keywords:
Surface-enhanced Raman scattering; Ag-doped glass; Chemical plating Fig.1 Normal and
SERS spectra of glycine. 2500-fold enhancement was demonstrated. (note that different
registration time and concentration were used for two spectra).

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 4-12
Laser fabricated microelectronic circuits on flexible substrates
Alberto Piqué1, Nick Charipar1, Ray Auyeung1, Heungsoo Kim1 and Scott Mathews2
1

Materials Science and Technology Division, Naval Research Laboratory, Washington DC,
USA
2
Department of Electrical Engineering, The Catholic University of America, Washington, DC,USA

The use of laser-based direct-write techniques might revolutionize the way microelectronic
components such as interconnects, passives, IC’s, antennas, sensors and power sources
are designed and fabricated. The Naval Research Laboratory has developed a laser-induced
forward transfer process for direct-writing the materials required for the fabrication andassembly of the above components. The laser direct-write (LDW) system used for theseapplications is capable of operating in subtractive, additive, and transfer mode. In subtractivemode, the system operates as a laser micromachining workstation. In additive mode, thesystem utilizes the laser forward transfer process for the deposition of metals, oxides,
polymers and composites under ambient conditions onto virtually any type of surface. Finally,in transfer mode, the system is capable of transferring a single device, such as asemiconductor bare die, inside a trench or recess in a substrate, thus performing the samefunction of the pick-and- place machines used in circuit board manufacture. The use of thistechnique is ideally suited for the rapid prototyping of microelectronic components andsystems on plastic substrates for flexible electronics applications. This presentation will
discuss several examples of the types of electronic devices fabricated using LDW processes
on flexible substrates. This work was sponsored by the Office of Naval Research.

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The 8th International Symposium on Laser Precision Microfabrication
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Session 5 (LPM-5):

Nanotechnology and Nanomaterials

p. 94

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Th 5-01«Green» processing of stable and ultra-pure nanoparticles using
femtosecond laser-induced supercontinuum generation in water
Michel Meunier1, Sebastien Besner1 and Andrei V. Kabashin1
1

Laser Processing Laboratory, Department of Engineering Physics, École Polytechnique deMontréal, Case Postale 6079, succ. Centre-ville, Montréal (Québec), Canada, H3C 3A7

There is a need to produce nanoparticles using only environmentally benign reducing agent
and non-toxic materials for the stabilization of the nanoparticles which can be dissolved inwater. However, due to the very mild synthesis condition, processes based on «green»chemistry are characterized by a long reaction time (20-120h) and result usually in a
relatively size and shape dispersed nanoparticles distribution. We propose to use a two-steplaser-assisted method for the synthesis of small and low-dispersed colloidal nanoparticles, allperformed in only deionized water at room temperature, rendering this process very
environment friendly. As an example, we developed this process for producing gold
nanoparticles. As the first step, laser ablation from a gold target is used to fabricate relatively
large (few tens of nanometers) and size-dispersed colloids. As the second stage, selfmodification of the femtosecond laser pulse into a white-light supercontinuum is used toperform the secondary ablation of colloids. The fragmented species then re-coalesce to form
smaller, less dispersed and much more stable nanoparticles in the solution. The size of thenanoparticles after the treatment is independent of initial characteristics of colloids, but
depends strongly on laser parameters. Being prepared in pure deionized water, the colloidal
nanoparticles are stable and free of any impurities, making them unique for Surface
Enhanced Raman Scattering (SERS) and bio-imaging in vivo applications.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 5-02
Influences on nanoparticle production during pulsed laser
ablation
Anne Hahn1, Stephan Barcikowski1, and Boris Chichkov1
1

Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany

The generation of nanoparticles using pulsed laser ablation is already a well-known
technique. This method allows the generation of nanoparticles from a variety of materials andhas inherent advantages compared to the conventional methods, for example in the purity of
the fabricated nanoparticles due to the lack of precursors. But there are still no data on theinfluence of the media and laser parameters on the characteristics of nanoparticle production(e.g. size distribution, productivity). In this study we demonstrate the impact of pulse duration(nanosecond, picosecond, and femtosecond) on the particle size distribution. Additionally,
general differences between the laser ablation in air compared to the ablation in liquids will
be discussed. Our results indicate that the size distribution depends stronger on theirradiated area or spot size, as compared to the laser pulse energy. Furthermore, comparisonof both media is investigated regarding influence of laser pulse duration on the particle size
distribution and productivity for a variety of metal and ceramic materials. In this report, we
present an overview of parameters influencing the generation of nanoparticles by pulsed
laser ablation in air and liquids.

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 5-03
Silica nanomachining using laser plasma soft x-rays
Tetsuya Makimura1, Satoshi Uchida1, Takashige Fujimori1,
Hiroyuki Niino2, and Kouichi Murakami1
1

Institute of Applied Physics, University of Tsukuba
Photonics Research Institute, National Institute of Advanced Industrial Science andTechnology

2

Silica micromachining at high precision is required for (a) mold fabrication in nanoimprint, (b)nanometric chemical analyzers and chemical reactors in medicine and biotechnology, and (c)optical devices. For these applications, it is required to machine silica at high precision at low
cost. We have investigated silica nanomachining using laser plasma soft X-rays at around 10
nm [Appl. Phys. Lett. 89, 101118 (2006); 86, 103111 (2005); 85, 1274 (2004)]. Soft X-rays
were generated by irradiation of Ta targets with 532 nm Nd:YAG laser light with a pulse
duration of 7 ns, at an energy density of about 10 kJ/cm2. Under the condition, Ta plasma
emit light with energies of 10-500 eV, in addition to soft X-rays at around 100 eV (10 nm).
The soft X-rays were focused on samples with a spot size of 400 micrometers, using an
ellipsoidal mirror that we designed so as to focus soft X-rays at around 10 nm efficiently. The
samples were irradiated with soft X-rays through contact masks. We found that silica glasscan be machined by irradiation with laser plasma soft X-rays. Furthermore, it is remarkablethat surface roughness is about 1 nm after 10 shot irradiation with soft X-rays at 50 nm/shot.
Ablation rate can be controlled by the fluence of soft X-rays in a range of 0.2-150 nm/shot. In
addition, we found that the ablation observed here requires high fluence beyond thethreshold, which have not been achieved by synchrotron radiation etching. In order toinvestigate lateral resolution, we fabricated a WSi mask with 175-nm-pitch line-and-spacepatterns on a silica glass plate. After irradiation with laser plasma soft X-rays, the WSi mask
was selectively removed by reactive ion etching. As shown by Figure, we found that a seriesof trenches with a width of 50 nm can be fabricated on silica glass. With further developmentof imaging optics, slilica nanomachining should be achieved by direct irradiation with laser
plasma soft X-rays without any contact mask.

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p. 98

24-28 April 2007, University of Vienna, Vienna, Austria

Th 5-04
Growth of bi-phase crystalline/amorphous Sm-Fe-Ta-N magnetic
nano-droplets fabricated by PLD
S.Kobe1,E. Sarantopoulou1,G. Draži1, Z. Kollia1, A. C. Cefalas21Jožef Stefan Institute, Nanostructured Materials, Jamova 39, Ljubljana, Slovenia
2
National Hellenic Research Foundation, TPCI, Athens 11635 Greece.

The magnetic properties of rare earth–iron intermetallic alloys in the form of thin films mainly
depend on the crystal structure and size and the stochiometry of the nano-(micro)composites [1]. The amount of deposited material in the form of amorphous (non-magnetic)
droplets of nano dimensions sets the upper limit of film magnetism achieved after further
annealing and nitriding. However, even without annealing and nitriding, the coercivity willappear in droplet-like film structures if the crystal (nitride) phase starts to grow within theamorphous nano-droplet. We report that growth of magnetic nano-crystal islands within theamorphous phase depends on the target composition and on processing parameters, suchas background pressure, energy, and distance between substrate and target. Sm2Fe17xTaxN3-σ magnetic nano-droplets were fabricated in situ under nitrogen backgroundpressure from the Sm13.8Fe82,2Ta4,0 target by pulse laser deposition using a molecularfluorine laser at 157 nm [2]. In contrast, nano-droplets fabricated from an Sm13.8Fe86,2target under similar experimental conditions but with a high vacuum or He backgroundatmosphere were non-magnetic in the absence of further annealing and nitriding. Using
analytical electron microscopy and a vibrating sample magnetometer, we found that themagnetism of the nano-droplets originated from Sm2Fe17-xTaxN3-σ crystal dots. The
crystals were 5–10 nm wide, encapsulated within ~50–100-nm amorphous spherical droplets. The crystal phase was formed during the cooling of the original amorphous liquid droplets inthe plume.
References[1] K. Žužek, P. J. McGuiness, S. Kobe, Magnetic monitoring of the nitriding process in SmFe-Ta-based alloys. IEEE trans. magn., 2003, vol. 39, 2983-2985. vol. 39, 2983-2985, 2003.
[2] S. Kobe, K. Žužek, E. Sarantopoulou, Z. Kollia, A. C. Cefalas. Applied Surface Science,Vol. 248, 349, (2005).

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24-28 April 2007, University of Vienna, Vienna, Austria

Th 5-05
Extensive laser nanopatterning by micro-particle lens arrays

W. Guo1,2, Z.B. Wang1, Lin. Li1, Z. Liu2, B.S. Luk'yanchuk3 , P. Crouse1, D.J. Whitehead1
1

Laser Processing Research Centre, School of Mechanical, Aerospace and Civil
Engineering, University of Manchester, Sackville Street, Manchester, M60 1QD, UK
2Corrosion and Protection Centre, School of Materials, University of Manchester, The Mill,
Manchester M60 1QD, UK
3

Data Storage Institute, DSI Building, 5 Engineering Drive 1, Singapore 117608,
Republic of Singapore

Laser-induced surface nanopatterning cross a large surface area is a challenging task.
Compared with electron beam and focused ion beam lithography techniques, laser process
has an advantage of simple setup, fast speed and massive processing. In this paper, a nearfield technique was developed to overcome the diffraction limit for direct laser surface
nanopatterning. For the first time, it was demonstrated that different nano-features can be
written on the substrates in a large surface area. By using an angular incident laser beamwith a self-assembled particle-lens array, millions of nanostructures can be accomplished bya few laser pulse exposure.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Session 6 (LPM-6):

Laser Hybrid and Media-Assisted
Processes

p. 100

The 8th International Symposium on Laser Precision Microfabrication

p. 10124-28 April 2007, University of Vienna, Vienna, Austria

We 6-01
Mechanisms of water assist for overcoming the self-limiting
effects of high aspect ratio machining of silicon and forminimising particulate redeposit
H. Howard 1, A. Conneely 1, G.M. O’Connor 1, T. Glynn 1, R. Jordan 2
1

National University of Ireland, Galway, National Centre for Laser Applications (NCLA),
Ireland.
2
Hewlett Packard Manufacturing Ltd, Leixlip, Co. Kildare, Ireland

UV DPSS laser micromachining has emerged as a tool that is widely used for high aspectratio machining of features in semiconductor materials. For machining of through-trenches insilicon, the machining rate reduces as the depth increases. For high aspect ratio trenches, it
is considered that the retention and re-deposition of laser generated particulate in the trench
is significant in impacting the machining rate. A water assist process can be utilised toprevent this reduction in machining rate and the mechanisms of this assist process havebeen studied. A review is presented of the possible mechanisms outlined in the literature forsuch water assist processes. In the initial stages of machining a trench, water assisted andnon-assisted machining rates are the same – it is found that the machining rates only begins
to differ at a particular trench depth where the aspect ratio reaches a certain critical value.
This indicates that contrary to other theories on water assist, that the water assist does notnecessarily enhance the actual ablation mechanism but increases the overall machining rate
through efficient removal of the laser generated particulate for high aspect ratio features.
Comparing cross sectional profiles for non-assisted and assisted machining and looking at
the particulate dissolved in the water assist provides further evidence to support this theory.

The 8th International Symposium on Laser Precision Microfabrication

p. 10224-28 April 2007, University of Vienna, Vienna, Austria

We 6-02
The hydrodynamic theory and simulation of liquid phase forlaser shock process
Che Zhigang1, Shi Tielin1, Xiong Liangcai1, Long Yuhong11

Huazhong University of Science & Technology

Laser shock processing can improve the anti-fatigue and anticorrosion performance of metal
use d for micro-device. The theory model is given to investigate a target with transparent
confining medium and painting coating layer irradiated by pulse laser considering potential
melting liquid phase of the target. The mechanics model is established, its initial conditions
adopt the modified model by Zhang wenwu etc, as according the basic equations of masscontinuity, momentum conservation and energy conservation. Matlab is used to research indetail and analyze the issue. Special attention is paid to the influence of liquid phase on peakpressure of shock waves at laser intensity of I0=2GW/cm2 - 4GW/cm2 using CFD(Computational fluid dynamics) soft to make simulation computation. Some referential
interesting results for future experiences are obtained.

The 8th International Symposium on Laser Precision Microfabrication

p. 10324-28 April 2007, University of Vienna, Vienna, Austria

We 6-03
Self-organized growth of sp3-bonded 5H-BN electron-emitter
micro cones prepared by plasma-assisted laser chemical vapor
deposition: experiments and modeling
Shojiro Komatsu1, Hironori Tanaka2, Yuhei Sato2, Yusuke Moriyoshi2, Eiichi Ohta3
1

National Institute for Materials Science,2
Hosei University,
3
Ricoh Corporation

Here we propose a repetitive photochemical-reaction and diffusion model for the fractal
pattern formation of sp3-bonded 5H-BN micro cones in laser-assisted plasma chemical vapor
deposition, which was observed experimentally and reported previously. This model
describing the behavior of the surface density of precursor species, gave explanations to (1)the “line- drawing” nature of the patterns, (2) the origin of the scale-invariant self similarity(fractality) of the pattern , and (3) the temperature-dependent uniform to fractal transition.
The results have implications for controlling the self-organized arrangements of electronemitter cones at the micro- and nano-scale by adjusting macroscopically the boundary
condition (Lx, Ly) for the deposition, which will be very effective to improve the electron fieldemission properties.
References
1. S. Komatsu, K.Okada, , Y. Shimizu, and Y. Moriyoshi, J. Phys. Chem. B 103,?3289(1999).
2. S. Komatsu, A. Okudo, D. Kazami, D. Golberg, Y. Li, Y. Moriyoshi, M. Shiratani, K. Okada,J. Phys. Chem. B 108, 5182 (2004).
3. S. Komatsu, D. Kazami, N. Tanaka, Y. Moriyoshi, M. Shiratani, K. Okada, J. Appl. Phys.
99, 123512 1-6 (2006).
4. S. Komatsu, D. Kazami, N. Tanaka, Y. Moriyoshi, M. Shiratani, K. Okada, J. Chem. Phys.
125, 084701 1-6 (2006).

The 8th International Symposium on Laser Precision Microfabrication

p. 10424-28 April 2007, University of Vienna, Vienna, Austria

We 6-04
Laser-induced writing of submicron surface relief gratings in
fused silica on-the-fly
R. Böhme1 and K. Zimmer1
1

Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318 Leipzig(Germany)

The high quality etching of transparent materials is still a challenge for laser processing. The
hybrid laser processing method LIBWE (laser-induced backside wet etching [1]) allows thedefined microstructuring of transparent materials like fused silica at low laser fluences andwith high quality. The etch process is based on the pulsed laser irradiation of backside of atransparent material that is in contact with an absorbing substance. Usually organic solvents
or solutions (hydrocarbons) are applied as absorbing liquid for LIBWE. The etching ischaracterized by a high surface quality and small etch rates [1,2]. Otherwise, thedecomposition of the organic liquids can distinctly alter the materials surface with respect totheir chemical and structural properties, which will be responsible for the observed incubation
effects at LIBWE [3]. Recent results show the application of liquid metals such as gallium foretching instead of organic solvents or solutions [4]. Liquid-metal-LIBWE features negligible
incubation effects and very large etch rates (100 600 nm/pulse) while the surface quality is
as high as for hydrocarbon LIBWE. For the etching of periodically sub-micron structures on asolid surface interfering laser beams are used generated by projection of diffraction masks.
In conjunction with the backside etching approach, submicron surface relief gratings withregular line or dot patterns can be realized on planar fused silica substrates in a one-step
direct fabrication process [5]. The large etch rates at LIBWE by means of the liquid metal
enable a high-speed processing; gratings with a period of ~ 700 nm and a height of morethan 100 nm can be etched onthefly with one laser pulse.
[1] J. Wang et al., Appl. Phys. A 68 (1999) 111.
[2] R. Böhme et al., Appl. Surf. Sci. 186 (2002) 276.
[3] R. Böhme et al., Thin Solid Films 453-454 (2004) 127.
[4] K. Zimmer et al., Appl. Phys. A 84 (2006) 455.
[5] R. Böhme et al., Appl. Phys. A 80 (2005) 433.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

p. 105

The 8th International Symposium on Laser Precision Microfabrication

p. 10624-28 April 2007, University of Vienna, Vienna, Austria

Session 7 (LPM-7):

Biomedical and Analytical Applications

The 8th International Symposium on Laser Precision Microfabrication

p. 10724-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-01
InvitedUltra-short pulse laser ablation of
biological hard tissue and biocompatibles
V. Wieger1, D. Brodoceanu2, F. Beer3, A. Moritz3, D. Bäuerle2, E. Wintner1
1

Photonics Institute, Vienna University of Technology, Wien,
nstitute of Applied Physics, Johannes-Kepler-University, Linz,
3
Dental School, Vienna Medical University, Wien, Austria.

2

The application of ultra-short pulse lasers (USPLs) to biological hard tissue and compatible
materials (like for dental restoration) in order to process cavities and more complicated structures is not yet a routine technique which can soon be implemented into practice. Its advantages, however, cover the feasibility of avoidance of collateral damage (i.e. thermal andshock wave), the creation of geometrically fully versatile and precise structures, and theoption of spectroscopic feedback. In this paper, new data are presented concerning ablation
rates and ablation thresholds of human and bovine dental hard tissue, dental composites andbone, i.e. compacta, spongiosa and cartilage, being ablated by various scanned USPLs withdifferent pulse durations. The data give evidence that even ps pulses yield very useful
results, and selective ablation may be beneficial for practical application. The morphology of
the cavities yielded by different scanning techniques is analyzed via environmental scanningelectron microscopy. Fig.: Bovine compacta ablated by Ti:S laser pulses scanned according
to an Archimedic spiral. Laser parameters: τπ = 700 fs and F = 0.65 J/cm², PRR = 1 kHz, 20
roundtrips. a) overall view, b) magnification of the rim.

The 8th International Symposium on Laser Precision Microfabrication

p. 10824-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-02
Laser-controlled pico-injector for nano-biodevices
Toshihiko Ooie 1,5, Masato Tanaka1, Tomonori Nakahara1, Shinji Hyodo2,
Yasuo Shinohara3 and Yoshinobu Baba1,4
1

AIST, Health Technology Research Center, Japan
2
Toyo Manufacturing Co., Ltd., Japan3
nstitute for Genome Research, The University of Tokushima, Japan
4
Graduate School of Engineering, Nagoya University, Japan
5
Graduate School of Advanced Science and Technology,
The University of Tokushima, Japan

Micro fluidic devices are powerful tools for the analysis of DNA, protein and other biopolymer
samples. However, they have no fraction function that enables further analysis and/or theuse of separated samples. For plastic-based disposable chips, complex systems such as
piezoelectric actuators, micro valves and micro heaters are not suitable because of theircosts. We developed a laser controlled injector, which has a laser unit outside and minimum
additional parts in chip, a piece of metal foil as a beam absorber and an ejection port.
Explosive vapor bubbles formed on a thin metal foil in a channel during laser irradiation
effectively ejected biopolymer samples of the water solution from the channel to outside. The
samples before and after ejection were analyzed by SELDI-TOF MS. The laser controlled
pico-fraction unit successfully ejected protein samples without the change of their mass
spectra.

The 8th International Symposium on Laser Precision Microfabrication

p. 10924-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-03Ultrafast-laser-processed zirconia and its adhesion to dental
cementNiko Bärsch1, Stephan Barcikowski1, Klaus Baier2
1

Laser Zentrum Hannover e.V., Hollerithallee 8, Hannover, Germany
2
Kugler GmbH, Heiligenberger Str. 100, Salem, Germany

All-ceramic dental crowns from yttrium-stabilised tetragonal zirconia polycrystal (Y-TZP) are
the cutting-edge solution for dental restorations, with regard to cosmetic aspects as well asmechanical durability. The material in its final hot-isostatically pressed constitution can bemachined with femtosecond lasers as the most precise, damage-free, and wear-free tool for
micromachining. The exact geometry shall be generated according to CAD data frompatients' dentitions. A processing station, including a 300 fs laser system, has been designed
based on previous investigations that have narrowed down optimal laser characteristics andnecessary processing dynamics. These requirements have led to a modular machine
concept with five-stage machining and high dynamics that will be presented. Fixation
between crowns and cement remains a weak point. Regarding its adhesion to dental cement,
Y-TZP naturally comes off worse than dentin. This is due to mechanical bonding to dentin
tubules - hollow perpendicular tubes travelling from the pulp to the enamel undersurface - towhich cements are mechanically locked at the surface of a dental stump. We haveinvestigated whether the fixation between cement and Y-TZP surfaces can be improved
similarly by artificial microstructures. Such structures can be added to the inner surface oflaser-processed dental crowns in a final step after ultrafast-laser-based manufacturing. The
investigations include basic studies on surface machining of Y-TZP with femtosecond pulses
and evaluate possible microstructures with regard to structure sizes and process efficiency.
Achieved practical values of adhesion between ceramic and cement are compared toestimations from numeric simulations. Measurements for similar applied microstructures turnout to be constricted by side effects. Still, the results demonstrate that microscopic
structuring does in fact enhance the adhesion and can therefore contribute to the overall
reliability of dental crowns.

The 8th International Symposium on Laser Precision Microfabrication

p. 11024-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-04
Investigation on laser dental implants decontamenation
A.Yousif1, M. Strassl1, F. Beer2, L. Verhagen3, M. Wittschier4, E. Wintner1
1

Photonics Institute, Vienna University of Technology,
Gusshausstr. 27/387, 1040 Vienna, Austria
2
Dental School, Vienna Medical University,
Währingerstr. 25A, 1090 Vienna, Austria
3
L.A.M Verhagen & R.G.H. Waanders Tandheelkundig Centrum,
Eschpark 9, 7131 TG Lichtenvoorde, Netherlands
4
Zahnarztpraxis Dr. Wittschier, Achdorferweg 5, 84036 Landshut, Germany

During the last decades, the use of dental implants for replacement of missing or extracted
teeth became more and more state of the art in dental prosthetic therapy. One of the mostprobable reasons for failure cases nowadays is periimplantitis. This type of inflammation isassociated with increased probing depth, mobility, bleeding and suppuration for the implant
representing the clinical symptoms of periimplantitis. Implant failure may be the result of one
or several pathogenic factors such as infection, implant contamination, trauma during
surgery, impaired healing and/or premature loading during the healing process. Conventional
surgical treatment of periimplantitis lesions can be performed in cases with considerable
pocket formation (pocket depth larger than 5 mm) and bone loss after the acute infection has
been resolved and proper oral hygiene has been instituted. Numerous methods for implantsurface decontamination have been suggested as part of the surgical treatment ofperiimplantitis. Actually, decontamination of infected implant surfaces can be achieved very
easily and effectively by application of laser radiation. In several studies bactericidal effect ofhigh-power microsecond pulse laser irradiation on contaminated dental implant surfaces
already has been demonstrated. As most of these studies were undertaken under the
aspects of medical needs, the view on the driving physical parameters was mostly not
sufficiently reported. Hence, the purpose of our study was to evaluate suitable parameters forlaser decontamination of titanium implant surfaces by employing pulses in the range of
microseconds generated by different laser systems. For this, special consideration had to betaken on heat deposition and surface changes to prevent bone necrosis and stimulate
reattachment of tissue. In our presentation, we will report the results for temperaturedevelopment and surface morphology of different laser parameters and their clinicalrelevance and limitations

The 8th International Symposium on Laser Precision Microfabrication

p. 11124-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-05
InvitedApplication of femtosecond lasers in opthalmology
Josef Stoiber1 and Günther Grabner1
1

Department of Ophthalmology, Paracelsus Private Medical University
Müllner Hauptstraße 48, A-5020 Salzburg, Austria

Lasers with ultrafast pulses have been developed to decrease the energy necessary to incise
tissues and to decrease damage to surrounding tissues. In ophthalmology, femtosecond
lasers have so far been used for corneal surgery. The fs-laser uses infrared light to precisely
cut the tissue by photodisruption. The specialized software is focusing the laser beam into
tiny, 2-3 micron spots of energy. The beam passes harmlessly through the outer layers of thecornea until it reaches its exact focal point within the corneal stroma. Upon reaching thisfocal point, the beam forms microscopic bubbles of carbon dioxide and water vapor.
Thousands of these bubbles are placed at a precisely controlled depth to define a dissection
plane. By interconnecting the bubbles very tightly, a corneal flap is created with remarkable
precision and accuracy. The technology enables the surgeon to precision-design the cuts interms of diameter, depth, edge angle, and morphology. At present, the main application in
ophthalmology is the creation of lamellar flaps for laser in situ keratomileusis (LASIK), a
procedure to correct myopia (nearsightedness), hyperopia (farsightedness), andastigmatism, and therefore to reduce patients’ dependency on contact lenses and glasses.
When used during LASIK, the fs-laser replaces the handheld microkeratome blade
traditionally used during surgery. Clinical studies show that the flaps are uniformly of goodquality with no flap complications. The flexibility of this system allows for intrastromal corneal
surgery and may make it useful also for other refractive and corneal procedures. Further
applications are the creation of pre-cut channels for intra-corneal ring segments and cuts forlamellar and perforating corneal transplantation, which represents an entirely new approachfor the correction of various corneal disorders.

The 8th International Symposium on Laser Precision Microfabrication

p. 11224-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-06
UV excimer laser ablation of RGD peptide grafted onto PET:
Impact on cell attachment
C. Chollet1, S. Lazare2, F.Guillemot1, M.C. Durrieu1
1

INSERM, U577, Bordeaux, F-33076 France ; Univ. Victor Segalen Bordeaux 2,
Bordeaux, F-33076 France
2
Laboratoire de Physicochimie Moléculaire (LPCM), UMR 5803 du CNRS,
Université de Bordeaux 1, France

Introduction: Poly (ethylene terephthalate) (PET) has been most widely used as biomedical
implant because of its desirable properties, such as strength and modulus. In order to favor
osteoblast cells adhesion onto PET, our work deals with grafting of RGD peptides on
surface. Indeed, the RGD peptide is well known to be the active sequence of adhesive
proteins of the extracellular matrix[1]. When hybrid biomaterials are produced, the current
consens is now to distribute the bioactive ligands in a controlled fashion in the form ofnanoscale-clusters or nanodomains, and no longer in a homogeneous or statistically based
way. As a result the aim of our study is to be able to produce nanostructured surfaces which
will present variable densities and distributions of peptides on the surface and monitor both
qualitatively and quantitatively cell adhesion[2]. Materials and methods: PET sample used is
a commercial film obtained from Good Fellow . The four subsequent steps for RGDC grafting
are: Hydrolysis with NaOH + water/acetonitrile; Oxidation with KMnO4 in H2SO4; NHS, EDC
grafting; RGD grafting [3]. Ablation was performed by laser onto the graft surface. It is
composed by KrF excimer laser (Lambda Physik LPX 220i) with μ= 248nm [4]. X-Ray
photoelectron spectroscopy (XPS), Optical profilometry, SEM and radiolabelling techniques
are applied to characterize the surfaces. Cell attachment studies were performed with
MC3T3 cell line. Conclusions: XPS results shown that RGD peptides were covalently grafting
to PET surfaces and peptide density was evaluated by high resolution µ-imager. Cell
adhesion on different materials (homogeneous and patterned) were studied by vinculin andactin labelling (immunogold labelling/SEM and fluorescent staining/confocal).
References:[1] Pierschbacher MD et al., Nature.1984;309:30[2] Maheshwari G et al., J. of Cell Science.2000;113:1677[3] Chollet C et al., Biomolecular Engineering.2006;Submitted.
[4] Chollet C et al., ITBM-RBM.2006;Submitted

The 8th International Symposium on Laser Precision Microfabrication

p. 11324-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-07
Surface functionalization of 2D and 3D structures using
biomolecules
Maria Farsari1, V. Dinca1,2, M. Dinescu2, S. Georgiou1 and C. Fotakis1
1Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology
Hellas (FORTH), P.O. Box 527, 711 10 Heraklion, Crete, Greece.
2
National Institute for Lasers, Plasma and Radiation Physics (NILPRP), Lasers Department,"Optical Processing of Advanced Materials" Group, 409 Atomistilor Street,
PO Box MG-16 Magurele, 077125 Bucharest, Romania

Bio-micro-array fabrication and biological molecule patterning has been the focus of muchresearch in recent years, as they are envisaged to play an important part in genomic studies,drug discovery and screening, protein identification and scaffolding development for tissue
engineering. However, there are still several issues remaining regarding biomolecules
malfunction in harsh environments, as these materials are chemically and structurally very
complex and heterogeneous and they easily lose their structure and biochemical activity due
to denaturing, dehydration or oxidation. A number of different approaches have been
examined for fabricating patterned biological surfaces. Almost in all cases, biomolecules
patterning has been two-dimensional. We demonstrate both 2D and 3D biomolecules
patterning using techniques which enable the construction of arbitrary two and three
dimensional shapes, not restricted to array-based shapes. For the 2D printing, Laser Induced
Forward Transfer (LIFT) is employed to deposit controlled and viable micro-patterns of avariety of biomaterials. The activity and the functionality of the transferred materials is shown.
For the 3D printing, firstly micro-structures are made employing multi-photon polymerization.
Biotin is subsequently immobilized on the surface of the structures by excimer laser photoactivation of photobiotin and further exposed to fluorescently labelled avidin. The specificityof the binding is demonstrated. The methods allow not only prototyping but also direct device
construction.

The 8th International Symposium on Laser Precision Microfabrication

p. 11424-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-08
Scanning of Ultra-Short Laser Pulses in Dental Applications
Martin Strassl1, Ernst Wintner1
1

Photonics Institute, Vienna University of Technology

In the last years ultra-short laser pulses have proved their potential for application in medical
tissue treatment in many ways, especially for the most sensitive dentinopulpal com-plex inteeth. In hard tissue ablation their aptitude of material ablation with negligible collat-eral
damage brings many advantages. Up to now it was shown by many authors that theapplication of picosecond or femtosec-ond pulses allows to perform an ablation to thephysiological requirements. Beside the short interaction time with the irradiated matter,scanning of the ultra-short pulses turned out to be crucial for ablating cavities in the required
quality. One reason for this can be seen in the fact that during scanning the time period
between two pulses falling repetitively on the same spot is so long that no accumulation
effects occur and each pulse can be taken as a first one. In our talk we present the actual
results of our investigations on optimizing different pulse durations and scanning patterns.
They allow to create cavities without collateral damage by a constant irradiation of thescanned area and to avoid any irritation to the pulp being one of the most important
prerequisites for pain free dental treatment. In simulation and experi-ments the theoreticalenergy distribution and the practical ablation behaviour are compared and discussed. Figure
Caption: Left: Simulation of the energy distribution of an x/y-scan. A flat top shaped energy
distribution is preferred to yield constant ablation quality and depth. Right: ESE micrograph ofa cavity prepared by an r/phi scan. The rotational geometry has the advantage to allow thesimulation of a conventional drill. Furthermore, this shape is insensitive against translational
move-ments in any direction.

The 8th International Symposium on Laser Precision Microfabrication

p. 11524-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-09
Autofluorescence of electrophoresis chip grooved by excimer
laser
Hidetoshi Miyashita1, Toshihiko Ooie1
1

National institute of Advanced Industrial Science and Technology,
Health Technology Reseach Center

The spectra of autofluorescence from the grooves of electrophoresis chip machined by a KrF
excimer laser were measured by a fluorophotometer equipped with the 2nd harmonic of
Nd:YAG laser as excitation source. Acrylic plastics (PMMA) were used as the specimen.
Total fluorescence of laser machined groove in a wavelength range between 580and 750nm
strongly depended on the fluence of laser and could be reduced by the optimization of thefluence. However, the intensity of fluorescence was still high at the best condition comparedwith an electrophoresis chip formed by injection molding. For further reduction of
autofluorescence of laser machined groove, we used a solvent, GG developer that contains
60 wt% of 2-(2-n-butoxyetoxi) ethanol and 20 wt% of morpholine and 5 wt% of 2aminoethanol. Etched by the solvent, the autofluorescence of the grooves was dramatically
improved as to applicable for practical electrophoresis. The electrophoresis signals of thechip formed by the combination of laser grooving and solvent etching were compared to thatof the chip by conventional injection molding. The spectra of autofluorescence fromacrylicplastic specimen excited by green laser (532nm) after laser irradiation is shown by thinline in the Figure. After laser irradiation and etching the spectra of autofluorescence from thegroove is shown by heavy line in the figure.

The 8th International Symposium on Laser Precision Microfabrication

p. 11624-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-10
Biofunctional photopolymers for micro-stereolithography
J. Stampfl1, M. Schuster1 ,R Inführ1 , F. Varga2 , C. Turecek2 , R. Liska2
1

Vienna University of Technology
Ludwig Boltzmann Institute for Osteology, Vienna

2

Micro-Stereolithography (µSL) is a computerized fabrication technique that has gained
increasing interest in tissue engineering applications because of its ability to produce objects
with complex geometry and inner structure, like cellular structures as they appear in naturalbone. In these investigations we aim at the development of a new polymers for tissue
engineerign, that can be formed by µSL and fulfills the requirements from the medical pointof view. For that an acrylate-based monomer formulation has been developed by testing
several commercially available acrylic compounds concerning photoreactivity, mechanicalproperties and biocompatibility. By use of a modified gelatin as a photoreactive crosslinker
biodegradability can be introduced into the polymer. Further components of such aformulation are appropriate photoinitiators and filler materials to further improve themechanical properties and to act as Ca source in the body in the case of bone replacement.

The 8th International Symposium on Laser Precision Microfabrication

p. 11724-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-11
Laser-induced forward transfer of liquids for miniaturizedbiosensors preparation
P. Serra1, M. Duocastella1, J.M. Fernández Pradas1, M. Colina1 and J.L. Morenza1
1

Universitat de Barcelona, Applied Physics and Optics Department Martí i Franquès 1,
E08028-Barcelona, Spain

The high focusing power of lasers makes them adequate for the development of direct
writing techniques for micropatterning purposes. Although most laser direct writing
techniques are essentially subtractive, lasers can also be used as additive tools in several
ways. One of the most common configurations is the corresponding to laser-induced forward
transfer (LIFT). In this approach, a small amount of material is directly transferred from adonor thin film to a receptor substrate placed parallel and in close proximity to the film.
Transfer is induced by a laser pulse focused on the film through its transparent support. In
traditional LIFT, the donor thin film is solid, and the fraction of transferred material iscompletely vaporized by the laser pulse; deposition takes place through recondensation of
the laser-generated vapor on the receptor substrate. This transfer mechanism makes thistechnique feasible for the deposition of some inorganic materials, like metals and oxides, butuseless for more complex materials which structure is irreversibly damaged after
vaporization, like polymers or biological molecules. However, it is also possible to induce
material transfer from liquid films; in this case the process takes place through direct ejectionof droplets from the film, with no significant phase change (see the scheme in the figure).
This makes feasible the deposition of complex materials through their previous suspension ina liquid solution, since the material of interest is then dragged by the solvent during transfer
instead of being vaporized, thus preventing it from decomposition. Under these conditions,transfer occurs in a way very similar to ink-jet printing. The capability of LIFT of transferring
complex materials without degradation makes this technique adequate for miniaturizedbiosensors preparation: patterns of biomolecules can be accurately deposited with a highdegree of spatial resolution (see droplets of 10 µm diameter in the figure) and without loss of
their biological activity. In this work we investigate the physical processes and parameters
determining the characteristics of the micrometric patterns deposited through LIFT for the
preparation of minitaturized biosensors.

The 8th International Symposium on Laser Precision Microfabrication

p. 11824-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-12
Bio-microchips fabricated in transparent materials by
femtosecond laser
Yasutaka Hanada1, Koji Sugioka1, Ikuko Ishikawa1, Hiroyuki Kawano1, Katsumi Midorikawa1
1

RIKEN - The Institue of Physical and Chemical Research

Observation and analysis of living cells and microorganisms are currently important subjects
for biologists due to the pursuit of origin of life and bio-motor applications. Their common tool
for this study is an optical microscope with a high numerical aperture (NA) objective lens.
They strongly demands to three-dimensionally confine the living cells and microorganism inan area as small as possible for easier observation since the high NA objectve lens limits
both the field of view and the depth of focus. We applied our technique fabricating threedimentional (3D) hollow microstructures inside photosensitive glass by fs laser for
manufacture of a microchip, in which a simple microchannel was embedded in the glass, forobservation of Euglena. In the meanwhile, to integrate some functions to the microchip isrequired for some other applications. In the present paper, we attempt to integrate amechanical component into the microchannel to investigate mechanism of informationtransmission in living Pleurosira. The procedure for fabricating the 3D hollow microstructuresconsists of (1) 3D direct writing by fs laser (775nm, 150fs, 1kHz),(2) baking to form themodified regions at the laser exposed regions, (3) wet etching in dilute HF solution to
selectively remove the modified regions, and (4) post annealing to smooth the etchedsurfaces. Figure 1 shows a microscope image of the fabricated microchip in which a movablemicroneedle is integrated into the microchannel. Motion of the microneedle is controlled by aCu tube connected to the miconeedle. When the tip of miconeedle is stuck to one of the cellsof Pleurosira, its information is transmitted to other cells successively. As a result, it isobserved that Chloroplast gather to the center of each cell as shown in Fig. 2. This
Phenomena is considered to be similar to the information transmission in neuronal cells andthereby is of great use for understanding neuron network mechanism.

The 8th International Symposium on Laser Precision Microfabrication

p. 11924-28 April 2007, University of Vienna, Vienna, Austria

Fr 7-13
Infra-red (1064 nm) laser printing of biological elements:
preliminary results
Fabien Guillemot 1, Agnès Souquet 1, Marc Faucon ², Céline Chollet 1, Reine Bareille 1,
John Lopez ², Marie-Christine Durrieu 1, Joëlle Amédée 1
1

INSERM, U577, Bordeaux, F-33146 France ; Univ Bordeaux 2, Bordeaux, F-33146 France.
² ALPHANOV Centre Technologique Optique et Laser , Talence, F-33405 France.

Considering microarrays generation, biomaterials surface treatment or else tissue
engineering, laser printing of biological elements such as proteins, enzymes and cells iscalled to become an important tool in the future. In this aim, many processes have been
described under the names MAPLE-DW, LIFT or AFA-LIFT considering if the biologicalelements are embedded in an absorbing matrix or/and placed onto an metallic absorbing
layer. Principle works have involved pulsed UV lasers: Nd:YAG laser tripled in frequency (l =355 nm) or excimer lasers ( l = 193 and 248 nm) and thermal and thermo-mechanicalmechanisms have been proposed considering nanosecond lasers. In this study, we focus onlaser printing of cells and peptides for biomaterial applications. Experimental set-up included
a Nd:YAG laser (1064, 30ns), a galvanometric scanner, a gold (20-30 nm) absorbing layer
and a 30-50µm thick hydrogel matrix layer containing above-mentioned biological elements.
Peptides patterning were performed on a pre-functionalized poly(ethylene terephthalate)(PET) using radiolabeled peptides ([3H]-lysine) and observed by means of a high resolution
beta-Imager. In the other hand, human endothelial cells (EaHy926 cell line) were printed on a
glass slide varying fluence conditions. Short and long term viability of endothelial cells were
determined by live/dead assays. According to these preliminary studies, infra-red laser
printing seems to be an effective alternative to UV processes. However, deepest studies
should concern heat shock proteins expression in relation to optical parameters.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Session 8 (LPM-8):

Photochemistryp. 120

The 8th International Symposium on Laser Precision Microfabrication

p. 12124-28 April 2007, University of Vienna, Vienna, Austria

Fr 8-01
InvitedFemtosecond irradiation of a photosensitive zinc phosphateglass containing silver
Matthieu Bellec1, Lionel Canioni1, Bruno Bousquet1,
Clemens Hönninger2, Eric Mottay2
1

Centre de Physique Moléculaire Optique et Hertzienne, Université Bordeaux1,
351 cours de la liberation 33405 Talence Cedex, France
2
Amplitude Systèmes, 6 allée du doyen Georges Brus, F-33600 Pessac, France

We report on exposing a photosensitive zinc phosphate glass containing silver to infrared
femtosecond pulses. The used laser source is a directly diode-pumped high energy Yb:KYW
oscillator delivering pulse energies up to 1 µJ and pulse durations down to 430 fs, thus pulse
peak powers exceeding the MW level. The pulse repetition rate is 9 MHz and the average
power is on the 10-W-level. . This laser source is hence well suited for various micro- andnanostructuring applications. By focusing such a laser beam inside the zinc phosphate glass
containing silver glass, we can induce microstructures below the diffraction limit. Indeed,following exposure, we observed the formation of chemically stable silver clusters (Agnx+
with n<10). Several linear and nonlinear optical and spectroscopic time resolved techniques
allows probing the dynamic of the formation of these clusters. The mechanism of thephotoreaction is discussed. Following a thermal treatment, controlled creation of precious
metal nanoparticles inside glass could be achieved. Some applications should be considered
due to local modification of refraction index such as waveguides, gratings, photonic crystals
or 3D-microstructures.

The 8th International Symposium on Laser Precision Microfabrication

p. 12224-28 April 2007, University of Vienna, Vienna, Austria

Fr 8-02
Laser-induced forward transfer (LIFT) of sensitive materials
using a photolabile dynamic release layer
T. Lippert 1, A. Wokaun 1, R. Fardel 2, M. Nagel 2, F. Nüesch 2
1

Paul Scherrer Institut, General Energy Research Department, 5232 Villigen PSI,
Switzerland;
2Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for
Functional Polymers, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland;

Laser-induced forward transfer (LIFT) is one possible method to transfer materials ormaterial layers with micrometer resolution from a transparent transfer substrate to a receiver.
This technique utilizes laser to achieve the transfer and lateral resolution, and can be
performed “solvent-free” with the pure material. As lasers near-infrared or UV laser can beapplied, but in the case of sensitive materials, such as biomaterials or electroactive
polymers, thermal load or UV photons can be detrimental to the properties of thesematerials. We have therefore developed and tested photosensitive dynamic release layers(DRL) which absorb the laser photons and protect in this way the transfer layer. The DRL
functions also as pressure generator upon decomposition which enables the LIFT process(shown in scheme 1). It is of course important that the decomposition products will notcontaminate the transferred layer. The utilization of photopolymers, which completely
decompose into gaseous fragments, is the basis for this approach, while metallic DRL tend
to contaminate the transfer material. The DRL polymers are based on triazene functionalgroups that decompose into nitrogen while the other structural units of the triazene polymers
are utilized to obtain specific properties, e.g. solubility in certain solvents, including water,
surface polarity, or biocompatibility. We have studied and optimized the triazene-based DRL
with regard to film forming, optimum thickness for the transfer at a given laser wavelengthand fluence, optimum laser fluence. The optimized DRL system was then tested for thetransfer of sensitive materials, such as cells, water-soluble polymers, nanocrystals and in
most detail electroactive polymers, e.g. MEH-PPV (poly(2- methoxy,5-(2’-ethylhexyloxy)-1,4phenylene vinylene). The functionality of the transferred materials have been tested in detail,e.g. in the case of MEH-PPV by observing light emission. The application of the DRL allows
also the transfer of more than one layer in one step, i.e. the MEH-PPV with an electrode.

The 8th International Symposium on Laser Precision Microfabrication

p. 12324-28 April 2007, University of Vienna, Vienna, Austria

Fr 8-03
Laser photoionization and photodissociation method andtechnologies for cleaning the semiconductor materials andpreparing the films of pure composition at atomic level
Alexander V.Glushkov1, Andrey V.Malinovsky1, Sergey V.Ambrosov1
1

Odessa University

Method of laser photoionization and dissociation of molecules is very perspective method forcleaning semiconductor materials from admixtures. Laser cleaning of mono-silan represents
a great interest for technology of obtaining a poor Si in the semiconductor industry. The
paper is devoted to the search and modeling optimal schemes of laser technologies forcontrol and cleaning the semiconducting substances. Here at first we construct the optimal
scheme of laser photoionization technology for preparing the films of pure composition on
example of creation of the 3-D hetero structural super lattices (layers of Ga(1-x)Al(x)As withwidth 10Å and GaAs of 60Å). It includes at first step an excitation of atoms by laser field andtheir transition into Rydberg states and then ionization by electric field [2]. A creation of thefilms of pure composition (our problem is creation of the 3-D layers of Ga(1-x)Al(x)As withwidth 10Å and GaAs of 60Å) is directly connected with using photoion pensils of Ga, Al, As.
Similar pensils are created by means of the selective ionization method. Thenelectromagnetic focusing and deflecting systems will provide a creating 3D supper lattices.
Besides, we present a new multi-level optimized model for definition of maximal
effectiveness of laser action in process of photodissociation of molecules. Model is based on
the Focker-Plank type equation for density of molecules [2]. Parameters for optimal excitation
for molecules of HCl (PH3,SiH4)are defined. In fig. we present the data of computer testing
optimized model for HCl molecules (T=300K) and dependence (number of particles) offunctional: I(u)=Int.{f(x1,t1;x2,t2)h(x)dx} in vibration energy interval x~[15,21] (in units ofkT)upon x1, wavelength of laser radiation.
1.V.Letokhov, Laser Spectroscopy, N.-Y., 1997; Letokhov, L.Ivanov, Com. Mod.Phys. 12,188
1988)
2. A.Glushkov,L.Ivanov, J.Phys.B 26,L376(1993); A.Glushkov et al, Int.J.Quant.Chem. 104,562 (2005).

The 8th International Symposium on Laser Precision Microfabrication

p. 12424-28 April 2007, University of Vienna, Vienna, Austria

Fr 8-04
Micro-marking using violet laser diode with dyestuff andpigments on plastic surfaces
Hiroyasu Ueta 1,4, Yoshio Maeshima 1, Yutaka Tsujimoto 2, Keiu Tokumura 3,
and Takahisa Jitsuno 4
1

Hamamatsu Industrial Research Institute of Shizuoka Prefecture (Japan)
2
Shikibo Co., Ltd. (Japan)
3
NALUX Co., Ltd. (Japan)
4
Institute of Laser Engineering, Osaka University (Japan)

Laser Diode (LD) is very excellent light source with advantages in high efficiency, small sizeand lightweight and so on. Jitsuno et al. in Institute of Laser Engineering, Osaka University
corrected the wavefront distortion of a infrared LD (wave length 940nm) to provide a precise
spot, and tried to use the beam to direct processing. Because wavelength of Violet Laser
Diode (VLD: Wave length 405nm) is shorter than that of infrared LD, VLD is expected toobtain smaller beam spot. The wavefront distortion of a beam from a single-mode VLD with acollimator lens was measured and corrected to provide a precise focal spot. And using the
precise beam, we tried to print color marking on plastics. Figure 1 shows process of color
marking on plastics such as PET, PMMA, and PC. Disperse Dye (or pigment ) was mixed
into stock paste, and this color paste was coated on plastics and dried. The output beam ofthis VLD was focused on a plastic plate to which dyestuff or pigments were added to enable
color micro-marking without an absorbent. The part irradiated by the laser was marked, andunfixed dyestuff or pigments were removed with ethyl alcohol. Using this focusing VLD, color
micro-marking of 100μm font size on the plastic plate was achieved. Figure 2 shows micromarkings of 100μm and 200μm font size.

Fig. 1: Color marking process

Fig.

2: Micro-marking ona)100 µm b)200 µm

PET.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austriap. 125

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Session 9 (LPM-9):

Micro-Drilling and Cutting

p. 126

The 8th International Symposium on Laser Precision Microfabrication

p. 12724-28 April 2007, University of Vienna, Vienna, Austria

Fr 9-01
Micromachining with a high repetition rate femtosecond fiber
laser
Fumiyo Yoshino1, Alan Arai1, Yuzuru Uehara1
1

IMRA America, Inc.

Industrial micromachining applications with ultrashort pulse lasers are often difficult to makepractical due to the lack of robustness of the laser and the slow processing speed resulting
from the low repetition rate. In the past, amplified, femtosecond lasers produced high pulse
energies, but at a slow pulse repetition rate of around a kHz. The high repetition rateoscillators did not have enough pulse energy for micromachining of most industrial materials.
Fiber Chirped Pulse Amplification (FCPA) is bridging these two performance regimes,
producing relatively high pulse energies (compared to oscillators) and relatively highrepetition rates (compared to amplifiers) in a robust and reliable package. The FCPA µJewel
D-1000 has a flexible performance range that includes 10-µJ pulses at 100 kHz and 1-µJ
pulses at 1 MHz. The µJ pulses at MHz repetition rates enable some interesting
micromachining processes, particularly with transparent dielectric materials where thermal
accumulation begins to play an important role in the process. This paper expands on
previously reported work on micromachining of transparent materials using a high repetition
rate, femtosecond fiber laser.

The 8th International Symposium on Laser Precision Microfabrication

p. 12824-28 April 2007, University of Vienna, Vienna, Austria

Fr 9-02
Fine micro-welding of thin stainless steel sheet by high speed
laser scanning
Yasuhiro Okamoto1, Arnold Gillner2, Alexander Olowinsky2, Jens Gedicke2 and Yoshiyuki
UNO1
1

Okayama University, Japan
Fraunhofer Institute for Laser Technology ILT, Germany

2

Recently, since the size of component becomes smaller, then the welding of thin metal sheet
has been required. Besides, the flexibility of process is important according to theaccessibility in the case of small component. Fraunhofer Institute for Laser Technology had
developed the SHADOW® welding technology, in which the high speed joining with small
distortion is possible using pulsed Nd:YAG laser by a non-contact process. On the other
hand, Prof. Miyamoto had reported the possibility of high speed and high quality welding bysingle-mode fiber laser. The combination of micro beam and high speed laser scanning has
the benefits for welding of thin metal sheet. Therefore, the characteristics of micro-welding
for thin stainless steel sheet were investigated by high speed laser scanning, in which thewelding was carried out by high speed scanner system with single-mode fiber laser andpulsed Nd:YAG laser. The absorption condition of laser power at the start point of irradiation
had a great influence on the welding seam, because the heat conductivity immediately
progressed to the surface direction. Besides, large distortion was observed at the start andend point of laser irradiation even under low laser power and high scanning speed
conditions. Then, the controllability of welding depth was discussed, and welding seams
were also evaluated under various laser irradiation conditions. Welding depth of 25 µm sheet
can be controlled widely by smaller spot diameter of fiber laser and high scanning speed
compared to larger spot diameter of pulsed Nd: YAG laser. It was difficult to weld two sheetsof 25 µm stably in long length by larger spot laser beam, while smaller spot laser beam
makes it easy to weld two sheets of 25 µm even in long length. Therefore, the small diameterof laser beam is effective in the welding of thin sheet by the combination of high speed
scanning.

The 8th International Symposium on Laser Precision Microfabrication

p. 12924-28 April 2007, University of Vienna, Vienna, Austria

Fr 9-03
Microdrilling in steel with frequency-doubled ultrashort pulsed
laser radiation
M. Kraus1, S. Collmer1, S. Sommer1, F. Dausinger1
1

Forschungsgesellschaft für Strahlwerkzeuge (FGSW) (Germany)

It is shown in a wide variety of papers that microstructures of outstanding quality can be
manufactured by means of ultrashort laser pulses. Limiting the pulse energy with theobjective of melt reduction and enhancement of accuracy, however, leads to insufficient
productivity. Thus, the principle object of current research, particularly in the field of
microdrilling, is to raise the process efficiency, whilst maintaining the required precision.
Today, prototype solid-state lasers not only provide ps-pulses at repetition rates up to several
100 kHz, combined with adequate pulse energies, but also feature harmonic generation
units. These units convert the fundamental infrared wavelength into the second, third or evenfourth harmonic by frequency doubling and sum frequency generation in nonlinear crystals.
The frequency-doubled radiation exhibits better focusability as well as reduced widening anddistortion of the beam profile in a laser induced gas break down. The investigations
discussed in this article are focused on drilling at 1064 nm and 532 nm in austenitic CrNisteel. Fundamental research concerning the breakthrough time and the average drilling rate
was carried out on the basis of percussion as well as helical drilling. The main part of theexperiments, though, dealt with the fabrication of microholes with a diameter less than 100µm, utilizing a helical drilling process without core. Fig. 1: Microholes in 1 mm CrNi-steel. Leftside: 1064 nm. Right side: 532 nm. Manufactured with fully automated FGSW Helical Drilling
Optic at equal process parameters. Fig. 1 depicts two holes manufactured at 1064 nm and532 nm, respectively, in a 1 mm steel sample. By drilling with frequency-doubled radiation,
the hole quality improves considerably. The drilling generated at 532 nm shows a regularshape, smooth hole walls and an absence of recast. On top of this, the frequency-doubled
radiation widens the outlet to the predetermined diameter more efficiently and steadily.

The 8th International Symposium on Laser Precision Microfabrication

p. 13024-28 April 2007, University of Vienna, Vienna, Austria

Fr 9-04
Precision drilling of Ti6Al4V titanium alloy using pulsed Nd:YAG
laser

A. Demir1, M. Mutlu1, E. Akman1, E. Kaçar1, S. Karabay2 and T. Sınmazçelik1
1

University of Kocaeli, Laser Tecnologies Research and Application
Center, 41380, Umuttepe Kocaeli TURKEY
2
University of Kocaeli, Engineering of Machine, 41200, İzmit, Kocaeli
TURKEY
Since the introduction of titanium and titanium alloys in the early 1950s, these materials havein a relatively short time become backbone materials for the aerospace, energy, andchemical industries, because of their physical qualities of high strength, low weight. The mostimportant components of the aircraft gas turbine is made by titanium alloys due to its highmelting point (1677 ºC). In aircraft large numbers of effusion holes with small diameters are
required for improving the cooling capacity of turbine components. Because of laser can befocused very small area, most useful techniques for microholes drilling.
In this study, 150-250 micron diameter holes drilled on Ti6Al4V titanium alloys using pulsed
Nd:YAG laser. The effects of the laser parameters are investigated. In order to understandthe physical process during the drilling process laser pulse duration, energy, and pulse topulse time were changed systematically. And also the laser-material interaction wasmonitored using speed camera. The micro structures were analyzed using optic microscope.

The 8th International Symposium on Laser Precision Microfabrication

p. 13124-28 April 2007, University of Vienna, Vienna, Austria

Fr 9-05
Comparing DPSSL micro drilling and cutting applications at
different wavelengths
D. Ashkenasi1, A. Schirrmacher11Laser- und Medizin-Technologie GmbH Berlin (LMTB),
Schwarzschildstr. 8, 12489 Berlin, Germany
2
Azura Laser AG, Am Schlangengraben 16, 13597 Berlin, Germany

New strategies in laser micro processing are being developed with increasing interest andintensity using diode pumped solid state laser (DPSSL) systems generating short or ultrashort pulses at good beam quality. Outside the traditional laser guided micro machining of
metals and - more recently – semiconductors, less versatile candidates for laser machining
such as ceramics, crystals and technical glass are coming into focus. Hence, questions
concerning the right choice of laser wavelength are addressed with great concern. However,by using short (ns) pulsed laser light with sufficient peak power, additional non-linear
absorption channels are utilized to induce a material reaction even at under classical aspects
non-favorable wavelength conditions. To be able to “dial” between IR (1064 nm), green (532nm) and UV (355 nm) laser pulses, a newly designed diode-pumped q-switch Nd:VO4 laser
system by Azura Laser AG was implemented at the laser laboratory. The Mesa-15V is acompact and air-cooled system with off-resonator frequency conversion crystals, yielding ca.
10 W in the IR, 4.5 W in the green and 2 W in the UV (at 15 kHz) simply by “polarization
tuning” using two different lambda/2 plates inside ultra-flat opto-mechanical units. This study
reports on different laser drilling and cutting application near experiments performed at thesethree different wavelengths using the identical DPSSL system MESA-15V. For example,
results on laser scribing, dicing and cutting of technical glasses such as B33 and D263T will
be compared for 1064, 532 and 355 nm at <30 ns pulse width in TEM00 at average powers
up to 10W and discussed in respect to potential applications in display technology, microelectronics and optics.

The 8th International Symposium on Laser Precision Microfabrication

p. 13224-28 April 2007, University of Vienna, Vienna, Austria

Th 9-06
Laser micro-perforation “on-the-fly“ as an essential step of anovel process combination for micro-sieve production
Klaus Dickmann1, Marc Baumeister1
1

Laser Centre University of Applied Sciences Münster (LFM) Stegerwaldstraße 39 48565
Steinfurt Germany

A novel two-step technique, capable of performing large pore matrices (100 pores/mm2) inthin stainless steel foils (10 µm < foil thickness < 300 µm) is maintaining high processing
rates and pore widths < 5 µm. This process combination is initiated by high-speed singlepulse perforation “on-the-fly” with use of a brilliant fibre laser. This laser source combines
ample output power with an excellent beam quality (M2 = 1.1). The high drilling rate (5000
drillings/second) which can be achieved by use of this technique makes it an attractive option
for the creation of large bore matrices and widths smaller than 15 µm (fig. 1). The second
step consists in cold-roll forming of the previously laser micro-perforated foil. Thismechanically induced plastic deformation leads to a pore size reduction (in one dimension)
perpendicular to the rolling direction. However, in filtration applications (e. g. separation of
spherical particles) the minimum pore width determines the filtration parameters. Thus, many
separation applications benefit from this special pore shape with a minimum pore width ofless than 5 µm. Applications can be found in the fields of bio-medical applications and life
sciences. High-precision laser single-pulse perforation represents the basis of this process
combination. As a result of the micrometer dimensions and high processing rate evensophisticated high-speed camera systems fail to give insight into the laser-materialinteraction and liquid ejection process. At present, process results are optimised byexperimental studies. In order to determine the influence of the independent parameters on
the overall thermal and drilling efficiency FEM analysis of the single-pulse “on-the-fly”
perforation is carried out. Fig. 1 SEM image of high-speed laser-micro perforated stainlesssteel foil (50 µm thickness, 1.4301, electro-polished) with a drilling rate of 2500
drillings/second. Up to now a maximum drilling rate of 5000 drillings/second was achieved.

The 8th International Symposium on Laser Precision Microfabrication

p. 13324-28 April 2007, University of Vienna, Vienna, Austria

Th 9-07
Melt Dynamics and Burr Formation during Drilling with
Ultrashort Pulses
A. Michalowski1, D. Walter2, F. Dausinger1,2
1

IFSW Institut für Strahlwerkzeuge Universität Stuttgart Germany
FGSW Forschungsgesellschaft für Strahlwerkzeuge Stuttgart Germany2

On the fast growing market of precision micro-machining of metals there are not only lasers
which compete with other methods of drilling, but strong competition is also observed among
different laser-processing strategies. For processes which are in need of highest productivity,e.g. drilling of cooling holes in turbine blades, drilling with a long single pulse is typical. In thatcase the material removal is nearly completely performed by melt ejection. For better qualityof holes, a reduction of energy density and pulse duration is needed which leads topercussion and helical drilling strategy. Although the fraction of evaporated material
increases in that case, there is still material removal due to melt ejection during material
processing, even for femtosecond pulse durations. Highest precision without detectablematerial recast requires very small pulse energies and therefore seems to defeat productivity
needed in most cases. Significant advances in productivity of drilling imply deeper
understanding of melt dynamics, which can be obtained by diagnostics of the process. The
difficulties are the short timescales of the physical processes activated by ultrashort laser
pulses and a small scale of the objects under investigations, which are difficult to resolve
optically. Because the high aspect ratios of laser drilled holes does not allow in general direct
observation of the interior during processing, helpful information can also be obtained byexamining droplet ejection, hole formation and accumulation of recast.

The 8th International Symposium on Laser Precision Microfabrication

p. 13424-28 April 2007, University of Vienna, Vienna, Austria

Th 9-08
Laser percussion drilling of aerospace materials with a 20kW
peak power fiber delivered pulsed Nd:YAG Laser
Mohammed Naeem1
1

GSI Group, Laser Division

Fibre optic delivery of high powered Nd-YAG laser light for material processing is now welldeveloped with respect to laser welding, surface treatment or laser cutting. The application of
optical fibres technology to laser drilling has been at a much slower pace due to a number oftechnical problems. The two main problems are the relative low damage threshold of opticalfibres and the preservation of beam quality. The drilling parameters for aerospacecomponents usually use pulse widths in the millisecond range. Though laser damage
thresholds in optical materials have been extensively reviewed, unfortunately the available
data relates generally to nanosecond laser pulses and very little systematic data has been
published in the microsecond and macrosecond regimes. The other problem is that as thefibre diameter is increased the beam quality deteriorates. An M2 of 25 or better, given theright pulse parameters should produce an acceptable hole. The aerospace industry would
like to move to a fiber delivery system because laser drilling via an optical fiber can offer anumber of advantages i.e. • An optical fiber laser beam delivery system offers the option ofstandardising the beam path for all CNC machines. • Optical fibres homogenise the power
distribution across the laser beam giving a top hat profile. • An optical fibre allows the use ofbeam sharing optical components so that an aerospace component of the right geometry canbe drilled in either of two configurations. This paper investigates laser percussion drilling witha high peak power pulsed Nd: YAG laser (up to 20kW) fitted a 300µm fiber. Holes were
drilled with various laser and processing parameters on coated and uncoated nickel based
superalloy to quantify laser drilling times, recast layer, taper, oxidized layer and cracking

The 8th International Symposium on Laser Precision Microfabrication

p. 13524-28 April 2007, University of Vienna, Vienna, Austria

Th 9-09
3D modelling of laser hardening and tempering of hypoeutectoid steels
G. Tani 1, L. Orazi 2, G. Campana 1, A. Fortunato 1, G. Cuccolini 2
1

DIEM - Mechanical Engineering Department, University of Bologna.
Viale Rosorgimento 2, 40136 Bologna - Italy.
2
DISMI – Department of Science and Methods for Engineering,
University of Modena and Reggio Emilia. Via Fogliani 1, 42100 Reggio Emilia - Italy.

Laser hardening of steels gained an undoubted interest in today’s manufacturing technology
thanks to its direct applicability on the production line. The possibility to deal with small,circumscribed and complex surfaces makes possible to obtain highly localized and costeffective heat treatments. According to this consideration a accurate process set up, together
with the determination of technological process parameters, are primary aims to be achievedin order to obtain the desired results. This work presents a full featured software utility whichstarts from a customizable ferrite-pearlite distribution and simulates the resulting
microstructure due to laser heat treatment, taking into consideration every possible phasesuch as martensite, bainite and residual austenite. It also takes into consideration thetempering effect due to overlapping beam trajectories. These forecasts can be applied to any
3D geometry, both simple and complex, thanks to the exploitation of an advanced 3D meshgenerator and to the possibility to implement Laser beam path through a standard CN ISO
format. A wide experimental campaign performed on a complex 3D surface is described as amean of validation of the above mentioned software simulator.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Session 10 (LPM-10):

Micro-Welding and Bonding

p. 136

The 8th International Symposium on Laser Precision Microfabrication

p. 13724-28 April 2007, University of Vienna, Vienna, Austria

Fr 10-01
InvitedMiniaturized samples for bond strength and hermetic sealingevaluation for transmission laser joints
Golam Newaz1, Taslema Sultana1 and Hans Herfurth1
1Wayne State University Fraunhofer USA

Localized joining and hermetic sealing of dissimilar materials (metals, non-metals andpolymers) are critical requirements in miniaturized microelectronics, biomedical implants andtelecommunications/optoelectronic devices. These devices can combine components madeof a variety of materials including silicon, polymers, glass, ceramics and metals. Micro joining
and hermetic sealing of dissimilar materials can be achieved by localized laser joining. The
controlled heat input decreases the possibility for thermal damage to the highly sensitive
components with very precise heat affected zone (HAZ). To improve the performance andreliability of the existing laser joining technology- a better understanding is needed about theeffect of material properties in successful laser joining, the impact of the joint mechanism on
the materials, and a reiable way of evaluating the integrity of the joints.The efficacy ofminiature bond strength samples utilizing pressure induced bond separation and samples forhermeticity using miniature helium bomb test were developed evaluated for laser bonded
titanium coated glass/polyimide samples. Sample configurations are given in Fig. 1.
Successful results from these tests and meaningful failure modes establish these tests withminiature samples as good methods to determine the integrity of transmission laser joints.
The paper will describe in detail these results and provide the technical basis for utilizingthese tests for reliable assessment of quality of laser joints.

Fig. 1: Schematic of miniaturized
samples designed for (A) bondstrength evaluation and (B) hermeticity
testing(samplehassquareconfiguration, 5 mmX3mmX0.68mm).
The laser joints are shown in red

The 8th International Symposium on Laser Precision Microfabrication

p. 13824-28 April 2007, University of Vienna, Vienna, Austria

Fr 10-02
Laser transmission bonding and welding of silicon, glass andother brittle – rigid materials for micro systems
Fahri Sari1, Alexander Horn1
1

Fraunhofer Institute for Laser Technology Lehrstuhl für Lasertechnik, RWTH Aachen

Laser assisted transmission bonding with continuous wave (cw) Nd:YAG Laser by linear absorption of optical energy and laser induced transmission welding with ultra short pulsed
laser radia-tion by non-linear absorption of optical energy are suitable methods for joining of
hybrid microsys-tems made of silicon, glass and other brittle-rigid materials. Two different
technologies have been investigated for joining glass and other materials. The non-melting
process, laser induced selective bonding of silicon and borosilicate glass is based on thethermo-chemical principles building direct oxygen bridges between the joining partners.
Experimental results e.g. the determination of the me-chanical properties and the leaktightness using different functional intermediate layers at the inter-face between silicon andglass will be shown. An overview about possible application on other ma-terial combinations
to assemble complex hybrid systems will be given. With the second technique using IR-ultrashort pulsed laser radiation with pulse durations between 300 fs and 3 ps and large repetition
rates up to 5 MHz, technical glass plates (D263 SCHOTT) are welded together. Due to thevery large intensities in the focus using high NA objectives multi-photon absorption gets thedominant process and due to large repetition rates heat is accumulated and melting of theglass is induced. The mechanical stress within the welding zone is investigated byquantitative phase mi-croscopy and by optical microscopy of cross-sections the dimension of
the interaction zone is measured.

The 8th International Symposium on Laser Precision Microfabrication

p. 13924-28 April 2007, University of Vienna, Vienna, Austria

Fr 10-03
Laser micro welding in silicon solar module manufacturing
A. Moalem1, A. Schoonderbeek1, U. Stute1, B. Denkena1
1

Laser Zentrum Hannover (LZH), Hollerithallee 8, D-30419 Hannover, Germany

During the last years, the photovoltaic solar cell industry has experienced enormous growth.
However, for solar cells to be competitive on the longer term, both an increase in theirefficiency as well as a reduction in their cost is necessary. One opportunity for cost reductionthat laser technology can offer is laser micro welding as a substitute for conventionalsoldering methods in solar module manufacturing where single solar cells are interconnected
to solar strings. The advantages of laser micro welding are a shorter processing time and theabolishment of fluxing agent that forms an ageing risk. The challenge of this welding
application is to join parts with important differences in their thicknesses and consisting ofdifferent metals. In the developed laser process a tin plated copper joiner with a thickness of
100µm is welded on a silver metallization with a thickness of 10µm. To allow proper handlingof the solar strings, the welding zone has to withstand a peeling force of 10 N/cm.
Furthermore, damage of the silicon in the surrounding area has to be avoided. Results showthat with laser micro welding the electrical contact resistance of the joining zone can be
reduced by more than 90% compared to conventional soldering methods. Theoreticalinvestigations considering the temperature distribution and strategies for the laser power
deposition by pulse forming are described, in order to reduce the variance in durability and toachieve repeatable welding results.

The 8th International Symposium on Laser Precision Microfabrication

p. 14024-28 April 2007, University of Vienna, Vienna, Austria

Fr 10-04
Pulsed laser beam welding with filler wire
Le Guin André1, Richter Karsten1 Holtz Ronald11Lasag AG, C.F.L. Lohnerstrasse 24, CH-3602 ThunToday many laser beam welding processes already use the opportunity to work withadditional materials for example filler wire within the laser hybrid welding process. The use of
filler wire can be advantageous in aspects of metallurgical (i. e. for crack sensitive materials)
and geometrical reasons like gap bridging of butt joints or fillet welds. This process is alreadywell established in the “macro – industries” like automotive or shipbuilding industry utilizing
continuous wave lasers. However, for micro welding applications the use of a pulsed laser
with filler wire is less common. Its potential is investigated in this work. Therefore a laser
source with a free pulse shaping capability and the wire feeding system “Mini Drive” is used.
This allows to transport the wire in a continuous and pulsed manner in addition to an actively
controlled welding process which includes the melting of the wire and the base material
respectively, the welding phase and the cool down phase. This paper will give an overview
about the opportunities with a new welding concept targeted at critical weldments.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

p. 141

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Session 11 (LPM-11):

Deep UV Laser Application

p. 142

The 8th International Symposium on Laser Precision Microfabrication

p. 14324-28 April 2007, University of Vienna, Vienna, Austria

We 11-01
VUV laser technology for nanostructuring
Ralph Delmdahl1 and Burkhard Fechner11

Coherent GmbHThe capability of producing ever more dense and complex structures is pivotal for the
production of faster generations of microchips, increasingly capable micromechanical andmicrooptical systems (MEMS) as well as for downscaling biotechnological devices. Bothquality and longevity of the microstructures acting e.g. as sensors, actuators, bioreactors orinformation transmitters strongly depend on the degree of accuracy achieved in the
manufacturing process. Emitting at the shortest commercially available wavelength of 157nm
F2-lasers by nature are the laser source enabling the highest optical resolution. At the sametime, F2-lasers deliver the highest commercially available photon energy of nearly 8eV. This
allows even optical transparent compounds to be efficiently processed. In addition, heattransfer into neighboring substrate which facilitates melting or micro crack formation isvirtually eliminated by the interaction of material with high energy photons. As aconsequence, F2-lasers are the source of choice to manufacturing microsystems withunsurpassed quality. Recent progress in F2-laser technology in terms of output power andalso long-term operation of laser tube, resonator optics and gas lifetime makes today’s F2laser a reliable tool in pushing the envelop in nanotechnological developments.

The 8th International Symposium on Laser Precision Microfabrication

p. 14424-28 April 2007, University of Vienna, Vienna, Austria

We 11-02
Organic layer direct patterning using a DUV excimer laser
Kwang-Yeol Baek1, Doo-Young Kim1, Joong-Yong An1, Jong-Won Kim1, Hyoung Shik Kang1,
Soon Kook Hong1, Jung-Hun Son2, Jae-Won Chang2, Sung-Eun Lee2
1

Laser Solution Group, LG Production Engineering Research Institute,
LG Electronics 19-1 Cheongho-Ri, Jinwuy-Myun, Pyuntaeksi, KyunggiDo, 451-731
2
LG Electronics Institute of Technology,
LG Electronics 16 Woomyeon-dong Seocho-gu, Seoul, 137-724, Korea

In this study, the pentacene patterning is performed using DUV excimer laser and mask
projection technique. The pentacene, organic material is used as an active layer of Organic
Thin Film Transistor(OTFT) because of their high carrier mobility (>1.5cm2/Vs) characteristic
and OTFT is an operating device for the backplane of flexible display. Conventional
fabrication process of pentacene pattern is vacuum plating using mask. It has limitation for
the fine pattern. However, excimer laser patterning can make more fine pattern thanconventional process and minimize solvent damage for the plastic substrate by elimination ofdeveloping and stripping. The process parameters are energy density and pulse shot
numbers on target substrate and the homogenizing optics is used to improve beam profile
quality. Surface morphology after laser ablation is observed by Scanning Electron
Microscope (SEM) and the pattern profile and residue after patterning are measured by
Atomic Force Microscope (AFM) and Atomic Emission pectrometer (AES).

The 8th International Symposium on Laser Precision Microfabrication

p. 14524-28 April 2007, University of Vienna, Vienna, Austria

We 11-03
Dynamics and VUV laser processing of functional polymericsurfaces
E. Sarantopoulou1, Z. Kollia1, A. C. Cefalas1, S. Kobe2
1

National Hellenic Research Foundation. Theoretical and Physical Chemistry Institute.
2
J ožef Stefan Institute, Nanostructured Materials, Jamova 39, Ljubljana, Slovenia

The physical principles and the advantages of using laser light in the Vacuum Ultraviolet(VUV) region of the spectrum to fabricate micro/nano-structures and thin films on organic
surfaces is presented. A number of novel approaches have been developed during the lastyears in the area of processing methodologies for micro-fabrication of devices. New
materials have been designed and efficient patterning methods have been proposed for the
fabrication of modern multi-analytic devices The 157 nm F2 laser is enhancing photochemical processing during patterning and is improving the resolution. The high value of theabsorption coefficient and the process of molecular photo-dissociation, in organic molecules
at 157 nm, allows atomic resolution depth control during laser ablation on the organic films,
with major applications in surface preparation of DNA films, preservation of cultural heritage
artifacts, biology and fabrication of bio-arrays [1, 3]. The common denominator for all theseapplications is the fact that nano-fabrication and control at VUV wavelengths allows atomic
resolution depth control with localized chemical changes under certain conditions on organic
substrates. The aim of this article is to present the physical principles, methodologies ofpolymer patterning based on self-assembly, surface localized etching and controlled
functionalization by VUV laser ablation.
[1] Y. Martelé, K. Callewaert, K. Naessens, P. V. Daele, R. Baets, E. Schacht, Mater. Sci. &Eng. C, 23, 341 (2003).
[2] E. Sarantopoulou, Z. Kollia , A.C. Cefalas , Z. Samardija, S. Kobe, Thin Solid Films, 495,(1-2), 45, 2006.
[3] E. Sarantopoulou,_Z. Kollia, I. Gomoiu, Appl. Phys. A83, 663-668 (2006).

The 8th International Symposium on Laser Precision Microfabrication

p. 14624-28 April 2007, University of Vienna, Vienna, Austria

PPo
osstteerr
P-01
Femtosecond laser surface modifications of stainless steels and their consequences on the
corrosion point of view
S. Valette1, P. Steyer2, B. Forest3, C. Donnet4 and E. Audouard4
1 Laboratoire de Tribologie et Dynamique des Systèmes, UMR CNRS 5513, 36 avenue Guy de
Collongue, 69134 Ecully cedex, France 2 Laboratoire MATEIS, UMR CNRS 5510, 20 avenue Albert
Einstein, 69621 Villeurbanne cedex, France 3 Centre Ingénierie et Santé, 158 Cours Fauriel, Ecoledes Mines de Saint-Etienne, 42000 Saint-Etienne, France 4 Laboratoire Hubert Curien, UMR CNRS
5516, 18 rue du professeur Benoît Lauras, 42000 Saint-Etienne, France

P-02
Production of nanoparticles with high repetition rate picosecond laser
Marijus Brikas 1, Stephan Barchikowski 2, Boris Chichkov 2 and Gediminas Raciukaitis 1,3
1 Institute of Physics, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania, 2 Laser Zentrum Hannover,Hollerithallee 8, D-30419 Hannover, Germany 3 Ekspla Ltd, Savanoriu Ave. 231, LT-02300 Vilnius,
Lithuania,

P-03
Excimer Laser Processing of CNT Backlight Unit
C.M. Chen
ITRI

P-04
Laser micro-machining on the single crystal diamond using Nd-YAG laser
Xiang-Rui Chou, Jia-Xing Wang, and Jeng-Shyong Chen*
Department of Mechanical Engineering, National Chung Cheng University, Taiwan * Corresponding
author Professor Department of Mechanical Engineering National Chung Cheng University
imejsc@ccu.edu.tw

P-05
DEBRIS-FREE ITO SURFACE MICROFABRICATION USING AN ECONOMIC 532nm
LASER – VISIBLE LIBWE
Ji-Yen Cheng*, Meng-Hua Yen*,**, Wen-Chih Hsu*, Tai-Horng Young*** Research Center for Applied Sciences, Academia Sinica Taiwan ** Institute of Biomedical
Engineering, National Taiwan University, Taiwan

The 8th International Symposium on Laser Precision Microfabrication

p. 14724-28 April 2007, University of Vienna, Vienna, Austria

P-06
TRANSPARENT CELL CULTURING DEVICE WITH INTEGRATED HEATER
Ji-Yen Cheng*, Meng-Hua Yen*,**, Wen-Chih Hsu*, Tai-Horng Young***Research Center for Applied Sciences, Academia Sinica Taiwan **Institute of Biomedical
Engineering, National Taiwan University, Taiwan

P-07
Excimer laser assisted growth and dehydrogenation of Silicon/Germanium thin film
multilayers
S.Chiussi, F.Gontad, P.Wójcik, P.González, J.Serra, C.Serra#, B.León
Dpto. Física Aplicada, E.T.S.I.Industriales, Universidade de Vigo, Spain #CACTI,Universidade deVigo, Spain

P-08
Burst pulse ablation of metals and dielectrics using a Ti:Sapphire femtosecond laser
Jiyeon Choi, Robert Bernath, Troy Anderson, Mark Ramme and Martin Richardson
College of Optics & Photonics CREOL & FPCE, University of Central Florida, Orlando, FL, USA

P-09
Pulsed Laser Deposition - UV Lasers and Applications
Ralph Delmdahl, Rainer Pätzel
Coherent GmbH, Goettingen, Germany

P-11
Optimizing and pulse compression of a 200-nJ chirped pulse Ti:sapphire oscillator
Péter Dombi (1,2) Péter Antal (1) Róbert Szipöcs (1) Júlia Fekete (1) Zoltán Várallyay (3)(1) Research Instiute for Solid-State Physics and Optics, Budapest, Hungary (2) Institut für Photonik,
Technische Univerität Wien (3) FETI Ltd., Budapest, Hungary

P-12
A Monte Carlo Model of Light Propagation in Tissue
Simona Dontu, Sorin Miclos, Dan Savastru, Vasile Babin
National Institute of R&D for Optoelectronics INOE 2000

The 8th International Symposium on Laser Precision Microfabrication

p. 14824-28 April 2007, University of Vienna, Vienna, Austria

P-14
Photoresponsive Polymer Structures
M. Farsari, J. Catherine, E. Tsiranidou, S. H. Anastasiadis, M. I. Lygeraki, M. Varda, A. Athanassiou,
C. Fotakis
Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas(FORTH), P.O. Box 527, 711 10 Heraklion, Crete, Greece.

P-15
The influence of plasma plume in laser milling for mold manufacturing
G. Tani1, L. Orazi2, A. Fortunato1, G. Cuccolini2
1DIEM - Mechanical Engineering Department, University of Bologna. Viale Rosorgimento 2, 40136
Bologna - Italy. 2DISMI – Department of Science and Methods for Engineering, University of Modena
and Reggio Emilia. Via Fogliani 1, 42100 Reggio Emilia - Italy.

P-16
Characterization of different fiber cleavage methods for Optimend(TM), a new mechanicalsplice.
Éric Weynant, Marc Lévesque, Alex Fraser, René Beaulieu, Patrick Zivojinovic
Phasoptx inc. Institut national d'optique (INO)

P-17
Formation of gratings by self-organization of chromium thin film on the glass substrate underirradiation with laser pulses
Mindaugas Gedvilas, Gediminas Raciukaitis, Kestutis Regelskis and Paulius Gecys
Institute of Physics, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania

P-18
Theory of interaction of intense laser radiation with atoms, nuclei and femto-second laser
plasma at surface and atomic dynamics with non-rectangular laser pulses
Alexander V. Glushkov, Olga Khetselius
Odessa University

P-19
A search of possible high power source of monochromatic gamma radiation and discharge ofthe metastable nuclei during negative muon capture
Alexander V. Glushkov
Odessa University

The 8th International Symposium on Laser Precision Microfabrication

p. 14924-28 April 2007, University of Vienna, Vienna, Austria

P-20
New cooperative laser-electron-nuclear effects in atomic and molecular systems in the strong
laser field
Alexander V. Glushkov Svetlana V. Malinovskaya
Odessa University

P-21
Direct writing of polymethyl-methacrylate and polycarbonate with ultrashort pulses for rapid
prototyping applications.
David Gómez, Igor Goenaga
Dpto. de Micro y Nanotecnologías, Fundación Tekniker, Av. Otaola 20, 20600 Eibar (Guipúzcoa),
Spain

P-22
PRODUCTION OF MICRO-PATTERNED AMORPHOUS Si/Ge BILAYERS AND THEIRCRYSTALLIZATION TROUGH LOW THERMAL BUDGET LASER ASSISTEDTECHNIQUES
F.Gontad, E. López, S. Chiussi, J.Serra, P. González, B. León
Universidade de Vigo

P-23
Nonlinear optical properties of heavy metal oxide film glasses produced by pulsed laser
deposition
D. Munoz-Martin, J. Gonzalo, H. Fernandez, J. Solis, J.M. Fernandez Navarro
Laser Processing Group, Instituto de Optica, CSIC, Madrid, 28006, Spain

P-24
Optical Near-field Interaction Between Neighboring Micro/Nano-particles
Z.B. Wang(1), L. Li(1), W. Guo(2), Z. Liu2, P.L. Crouse(1) , David Whitehead(1) , B.S. Luk'yanchuk(3), G. Dearden(4), K. Watkins(4)(1)Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering,
University of Manchester, Sackville Street, Manchester, M60 1QD, UK (2)Corrosion and Protection
Centre, School of Materials Science, University of Manchester, The Mill, Manchester M60 1QD, UK(3)Data Storage Institute, DSI Building, 5 Engineering Drive 1, Singapore 117608, Republic ofSingapore (4)Laser Group, Department of Engineering, University of Liverpool, Brownlow Street,
Liverpool L69 3GH, UK

The 8th International Symposium on Laser Precision Microfabrication

p. 15024-28 April 2007, University of Vienna, Vienna, Austria

P-26
Microfluidic waveguides fabricated on glass chips using femtosecond laser pulses
Fei He, Haiyi Sun, Zenghui Zhou, Ya Cheng and Zhizhan Xu
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics,
Chinese Academy of Sciences

P-27
FS-time-resolved phase contrast microscopy in dielectrics
A. Mermillod-Blondin, J. Bonse, R. Stoian*, A. Rosenfeld, I.V. Hertel** * Laboratoire TSI (UMR 5516
CNRS), Université Jean Monnet, 10 rue Barrouin, 42000 Saint-Etienne ** Presenting author, also at
Freie Universität Berlin, Fachbereich Physik, Germany
Max Born Institute for Nonlinear Optics and Short-Pulse Spectroscopy

P-28
Low-debris, efficient laser-produced tin plasma extreme ultraviolet source for the next
generation lithography
Takeshi Higashiguchi, Yusuke Senba, Sumihiro Suetake, Yusuke Sato, Akira Hosotani, Yukari
Takahashi, and Shoichi Kubodera
Department of Electrical and Electronic Engineering and Photon Science Center, University ofMiyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki, 889-2192 Japan

P-29
Quality glass processing using LIBWE method
Huang Zhiqiang, Hong Minghui, Tiaw Kay Siang
Data Storage Institute, Singapore, National University of Singapore, Chartered Semiconductors
Manufacturing

P-30
3D Micro/Nano-structure Fabrication of Phase-change Film
Y. Lin, M. H. Hong, L. S. Tan, C. S. Lim, L. P. Shi, and T. C. Chong
Department of Electrical and Computer Engineering, National University of Singapore, 1 Engineering
Drive 3, Singapore 117576 Data Storage Institute, DSI Building, 5 Engineering Drive 1, Singapore
117608P-32
Micro-drilling of ceramic using pulsed Nd:YAG laser
Elif Kacar, Erhan Akman, Timur Canel, Mesure Mutlu, Levent Candan, Arif Demir, Tamer Sinmazcelik
University of Kocaeli, Laser Teknologies Research and Application Center, 41380, Umuttepe Kocaeli
TURKEY

The 8th International Symposium on Laser Precision Microfabrication

p. 15124-28 April 2007, University of Vienna, Vienna, Austria

P-34
Laser photoionization method detecting of single atoms and products of nuclear reactions
Olga Khetselius
Odessa University

P-35
The generation of ultra-short VUV and X-ray pulses in atomic, molecular and cluster systems
in a strong laser field
Olga Khetselius, Alexander Glushkov, Alexander Fedchuk
Odessa University

P-36
Femtosecond laser microdrilling of Alumina (Al2O3) ceramic
S. H. Kim(1), I. B. Son(2) and S. H. Jeong(1)1. School of Information and Mechatronics, Gwangju Institute of Science and Technology. 2.
Advanced Photonics Research Institute, Gwangju Institute of Science and Technology

P-37
Influence of Laser Beam Irradiation Condition on Low Temperature Poly-Silicon
Crystallization using a High-power Diode Pumped Solid State Laser
Dae-Jin Kim, Gun-Seop Go, Hyun-Jung Kim, Seung-Hwan Eum, Gwang-Jae Lee, Doh-Hoon Kim
Research & Development Center, Kornic Systems, Co., Ltd.

P-40
Nano-patterning by Diffraction Mask-Projection Laser Ablation
Marisa Mäder, Thomas Höche, Jürgen W. Gerlach, Klaus Zimmer, Rico Böhme and Bernd
Rauschenbach
Leibniz Institute of Surface Modification, Permoserstrasse 15, D-04318 Leipzig, Germany

P-41
Microstructure studying of laser pulse irradiating metal targets in water
M. H. Mahdieh1, A. Chehreghani2, R. Fazeli3, M. Nikbakht4, and B. Gakovic5
1,2,3,4 Department of Physics, Iran University of Science and Technology, Narmak, Tehran, Iran 5
Institute of Nuclear Sciences VINä Atomic Physics Laboratory POB 522, 11001 Belgrade, Serbia

P-42Light diffraction on modulations of solid surface relief and low threshold IR multi-photon
laser-molecular dissociation on surface. Laser microscopy
Andrey Malinovsky, Alexander Glushkov, Sergey Ambrosov, Andrey Svinarenko
Odessa University

The 8th International Symposium on Laser Precision Microfabrication

p. 15224-28 April 2007, University of Vienna, Vienna, Austria

P-43
Estimation of pulsed laser Ablated Polyimide Sizes
Nastaran Mansour and *Narges Amiri
Department of Physics, Faculty of Science, Shahid Beheshti University, Evin 1983963113, Tehran,
Iran *Department of Physics, Azad University of Mahalot, Mahalot, Iran

P-44
Pulsed Laser-Induced Surface Modification of Silicon in Liquids
Nastaran Mansour, *Samar Etemad , Rouhollah Karimzadeh and Javid Zamiranvari
Department of Physics, Shahid Beheshti University, Tehran, Iran *Department of Biology, Shahid
Beheshti University, Tehran, Iran

P-45
Femtosecond laser induced forward transfer (LIFT) process for skutterudite thin film
patterning
Marius Dumitru, Marian Zamfirescu, *Anne Daucher, Dan Colceag, Razvan Dabu, Maria Dinescu
National Institute for Laser, Plasma and Radiation Physics, 409, Atomistilor Str., PO Box MG 36,
077125, Magurele, Bucharest, Romania, Phone: +40-21-4574550, * Laboratoire de Physique desMate´riaux, UMR CNRS-UHP-INPL 7558, Ecole des Mines, Parc de Saurupt, F-54042 Nancy Cedex,
FranceP-46
Formation of Graded Band Gap in CdZnTe by Nd:YAG Laser Radiation
A.Mychko, A.Medvid',P.Onufrijevs, L.Fedorenko
Riga Technical University

P-47
Laser-Shaping of Hexagonal Ordered Triangular Gold Nanoparticles with Nanosecond
Pulsed Laser Light
Rodica Morarescu, Frank Hubenthal and Frank Träger
Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology – CINSaT,
Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Germany

P-48
Fabrication of DOE using Laser Direct Write Lithography System
Sumio Nakahara, Naoshi Ikemoto, Kyoji Matsushima, Shigeyoshi Hisada, Shoso Shingubara,
Takeyoshi Fujita
Dept. of Mechanical Systems Engineering, Kansai University, 3-3-35 Yamatecho, Suita, Osaka 5648680, Japan

The 8th International Symposium on Laser Precision Microfabrication

p. 15324-28 April 2007, University of Vienna, Vienna, Austria

P-49
Direct Laser Marking on CD ROM for Identification
Sumio Nakahara*,**, Shinpei Katou***, Yoshihiro Okino*, Masaaki Takita****, Shigeyoshi Hisada**,and Takeyoshi Fujita***HRC of Kansai University,**Dept. of Mechanical Engineering, Kansai Univ., ***Graduate school of
Kansai University, ****Takita Research & Development Co., Ltd.

P-51
Process of glass-ceramics reverse crystallization under Nd:YAG laser action
B.Yu. Novikov, V.P. Veiko
St.Petersburg State University of Information Technologies, Mechanics and Optics

P-52
Thin metal sheet bending and residual stresses relaxation by ns-pulse lasers in MEMS
manufacturing
J.L. Ocaña, M. Morales, C. Molpeceres, J.A. Porro, O. García
Centro Láser UPM. Universidad Politécnica de Madrid. Campus Sur UPM. Edificio "La Arboleda" Ctra.
de Valencia, km. 7,3 28031 Madrid. SPAIN

P-53
Laser-assisted micromachining of Fe-alloys using a novel thermochemical etching techniquewith an optical fiber
Kwang H. Oh, H. D. Im and S. H. Jeong
School of Information and Mechatronics Gwangju Institute of Science and Technology (GIST)

P-54
Aligned Growth of ZnO Nanowire by Catalyst-Free Nano-Particle Assisted Laser Deposition
Ruiqian Guo, Jun Nishimura, M. Higashihata and Tatsuo Okada
Kyushu University

P-55
Formation of Graded Band-gap in CdZnTe by YAG:Nd Laser Radiation
A.Medvid’1 L.Fedorenko2, B.Korbutjak2, S.Kryluk2, A. Mychko1, P.Onufrijevs1
1Riga Technical University, 14 Azenes Str., LV-1048, Riga Latvia, 2Institute of Semiconductor Physics
NAS of Ukraine, 45 Pr. Nauki, Kyiv, Ukraine

The 8th International Symposium on Laser Precision Microfabrication

p. 15424-28 April 2007, University of Vienna, Vienna, Austria

P-56
Interferometric femtosecond patterning of metals
Kimmo Paivasaari, Jarno Kaakkunen and Timo Jaaskelainen
Department of Physics and Mathematics, University of Joensuu, Finland.

P-57
Nano-particle generation from Femtosecond laser ablation of materials
N.Semalteanos, W. Perrie, M.Sharp, S.P. Edwardson and K.G.Watkins
Lairdside Laser Engineering Centre, The University of Liverpool, Wirral CH41 9HP, UK

P-58
Modification of phase change memory materials during interaction with excimer laser pulses
M. Popescu, F. Sava, A. Lorinczi, G. Socol, I.N. Mihailescu
National Institute of Materials Physics National /Institute of Lasers, Plasma and Radiuation Physics

P-59
Enhancement of sensing properties of thin poly(methyl methacrylate) films by VUV surface
modification(1)I. Raptis, (1)M. Chatzichristidi, (2)E. Sarantopoulou, (2)Z. Kollia
1Institute of Microelectronics, NCSR ‘Demokritos’ Athens, 15310, Greece 2Theoretical and Physical
Chemistry Institute, National Hellenic Research Foundation, NHRF Athens, 11635, Greece

P-60
MICRO/NANO SELF-ASSEMBLED STRUCTURES FROM BLOCKCOPOLYMER/SAMARIUM-IRON NANOPARTICLES HYBRID MATERIALS INDUCED BY
VUV LIGHT(1)S. Pispas, (1)E. Sarantopoulou, (1)K. Gatsouli, (1)Z. Kollia, (2) S. Kobe
(1) National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos
Constantinou Avenue, Athens 11635 Greece. (2) Jozef Stefan Institute, Nanostructured Materials,
1000 Ljubljana, Slovenia

P-61
Laser assisted delamination of paint by inductive heating
G.Schuoecker,T.Schumi
Institute of Forming and High Power Laser Technology, TU-Vienna

The 8th International Symposium on Laser Precision Microfabrication

p. 15524-28 April 2007, University of Vienna, Vienna, Austria

P-62
Correction of ditch-shaped defects during KrF excimer laser ablation using a mask projection
Dongsig, Shin Jahoon, Lee Jeong, Suh Jiwhan, Noh
KIMM (Korea Institute of Machinery and Materials) 171 Jang-dong, Yuseong-gu, Daejeon, South
Korea

P-63
Temperature Dependent Heat Generation by Optically Active Rare Earth Ions for Full Body
Cutting of LCD module
Kohei SOGA and Hiroshi MIURA*
Department of Materials Science and Technology, Tokyo University of Science 2641 Yamazaki, Noda,
Chiba 278-8510, Japan. *LEMI, Co., Ltd. 3-10-6 Daikan Yamato-City, Kanagawa 242-0025, Japan.

P-65
Laser micro-welding of dissimilar materials using femtosecond laser pulses
Takayuki Tamaki (a), Tomoyuki Inoue (a), Wataru Watanabe (b), Yasuyuki Ozeki (a), and Kazuyoshi
Itoh (a)(a) Department of Material and Life Science, Graduate School of Engineering, Osaka University (b)Photonics Research Institute, National Institute of Advanced Industrial Science and Technology

P-66
Dynamics of the shock wave accompanied by nanoparticle formation in the PLA processes
Toshio TAKIYA(1), Naoaki FUKUDA(1), Yasushi IWATA(2) and Minoru YAGA(3)Hitachi Zosen Corporation(1), Advanced Institute of Science and Technology(2), University of the
Ryukyus(3)P-67
Fabrication of microstructures on cemented tungsten carbide by a femtosecond laser
R. Tanabe, S. Fukami, Y. Ito
Nagaoka University of Technology

P-68
Surface morphology-dependent formation of ripples on Si, SiC, and HOPG substrates
Takuro Tomita, Ryota Kumai, Keita Kinoshita, Shigeki Matsuo, and Shuichi Hashimoto
Department of Ecosystem Engineering, The University of Tokushima

The 8th International Symposium on Laser Precision Microfabrication

p. 15624-28 April 2007, University of Vienna, Vienna, Austria

P-71
Laser Surface Nanotexturing and Applications
Wei Guo(1,2), Lin Li(1), Zhu Liu(2), Zengbo Wang(1) , Philip Crouse(1), David Whitehead(1)(1)Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering,
University of Manchester, Sackville Street, Manchester, M60 1QD, UK (2)Corrosion and Protection
Centre, School of Materials Science, University of Manchester, The Mill, Manchester M60 1QD, UK

P-72
Amorphous structure of ripple on SiC studied by micro Raman spectroscopy
Makoto Yamaguchi[1] Shigeru Ueno[1], Ryota Kumai[2], Keita Kinoshita[2], Takuro Tomita[2], Shigeki
Matsuo[2], Shuichi Hashimoto[2][1]Technical Research Institute JAPAN Society for The Promotion of Machine Industry [2]Departmentof Ecosystem Engineering, The University of Tokushima

P-73
Tribological property of DLC films with femtosecond-laser induced nanostructure
Naoki Yasumaru(1), Kenzo Miyazaki(2), Junsuke Kiuchi(3), Kenjiro Komai(1)(1) Fukui National College of Technology, (2) Kyoto University, (3) Eyetec Co., Ltd.

P-74
Femtosecond laser fabrication of metamaterials for high frequency devices
Marian Zamfirescu*, Razvan Dabu*, Marius Dumitru* George Sajin**, Florea Craciunoiu***NILPRP Bucharest, Atomistilor 409, 077125 Magurele, Romania **IMT Bucharest, Str. Erou Iancu
Nicolae 126A, 077190 Bucharest, Romania

P-75
Ultra-short pulse laser processing of Galium Nitride semiconductor epitaxial layers:theoretical modeling.
Irina N. Zavestovskaya Oleg.N. Krokhin Peter G. Eliseev
Lebedev Physical Institute of Russian Academy of Science

P-76
The Second-order Doppler Error of Laser Dual-frequency Interferometer
Zhiping Zhang, Zhaogu Cheng, Zhaoyu Qin and Jianqiang Zhu
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

P-77
Quality and Yield Enhancement of IR-Laser Ablation by Harmonics Seeding
S.Zoppel (1),(2), G.A.Reider(1)(1) Photonics Institute, Vienna University of Technology, Gußhausstraße 27-29, 1040 Vienna, Austria(2) Research Centre for Microtechnologies, Vorarlberg University of Applied Sciences, Hochschulstr.
1, 6850 Dornbirn, Austria

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

p. 157

The 8th International Symposium on Laser Precision Microfabrication

p. 15824-28 April 2007, University of Vienna, Vienna, Austria

P-01
Femtosecond laser surface modifications of stainless steels andtheir consequences on the corrosion point of view
S. Valette1, P. Steyer2, B. Forest3, C. Donnet4 and E. Audouard4
1

Laboratoire de Tribologie et Dynamique des Systèmes, UMR CNRS 5513, 36 avenue Guyde Collongue, 69134 Ecully cedex, France
2
Laboratoire MATEIS, UMR CNRS 5510, 20 avenue Albert Einstein, 69621 Villeurbannecedex, France
3
Centre Ingénierie et Santé, 158 Cours Fauriel, Ecole des Mines de Saint-Etienne, 42000
Saint-Etienne, France
4
Laboratoire Hubert Curien, UMR CNRS 5516, 18 rue du professeur Benoît Lauras, 42000
Saint-Etienne, France

To allow the identification and the traçability of surgical tools as well as prostheses, marking
is of prime interest in the field of biomaterials industry. Such kind of materials is subjected to
extreme conditions during sterilization or decontamination processes and justify the choice ofstainless steels. Nowadays, marking is often achieved by means of laser beam. Such kind ofmarking may involve modifications into the characteristics of the surfaces treated. These
modifications may be critical concerning the initial functions of the surfaces. Nd:YAG laserdelivering microsecond pulses are used in the laser marking industry. The aim of this work is
to study the behavior of the irradiated area in terms of corrosion resistance when the marking
is performed with femtosecond pulses compared to microsecond industrial devices.
Experiments have been performed on martensitic Z30C13 and austenitic 316L stainlesssteels. Electrochemical measurements (cyclic polarization curves) were carried out todetermine the passive state of samples before and after laser marking. Corrosion rate andtheir susceptibility to localized corrosion were also measured. Femtosecond laser marking isshown to provide an electrochemical ennoblement. Moreover, the chemical composition is
not affected so that the passive character of noth stainless steels is maintained, even
improved if we consider the susceptibility to localized corrosion.

The 8th International Symposium on Laser Precision Microfabrication

p. 15924-28 April 2007, University of Vienna, Vienna, Austria

P-02
Production of nanoparticles with high repetition rate picosecond
laser
Marijus Brikas1, Stephan Barchikowski2, Boris Chichkov2 and Gediminas Raciukaitis1,3
1

Institute of Physics, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania,
Laser Zentrum Hannover, Hollerithallee 8, D-30419 Hannover, Germany
3
Ekspla Ltd, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania,

2

Due to their size-specific and unique properties, nanoparticulate materials and composites
became increasingly popular, promising a breakthrough in the development of novel
methods in bioimaging, biosensing, and medical therapeutics. Chemical processes fornanoparticle production have huge production capacities, but purity of nanoparticles is still avery big problem, because they contain impurities from chemical agents and other additives
used in chemical reactions. Nanoparticle production by pulsed laser ablation of solidmaterials provides high purity nanoparticle colloids, which purity depends only on the purityof the solid. But, with respect to commercial applications, the production rate of nanoparticles
is limited by the average power and repetition rate of the applied laser systems. Compared to
femtosecond lasers, high repetition rate picosecond lasers show high ablation rate and low
thermal impact to the material, thus they have a great potential for the fabrication of
nanoparticles at high rate. Laser ablation in liquid produces charged nanoparticles and they
form a shell from dipole molecules (zeta potential), which protects them from agglomeration.
The ablation process in liquid is strongly affected by thermal distortion of the laser beam andformation of bubbles. These effects increase with higher power and higher repetition rate.
We present a flow chamber in which a high liquid flow rate across the sample surface allows
the successful solution of this problem. The generation rate of the silver nanoparticles inwater was 8.6 μg/s using 5.5 W laser power and 50 kHz repetition rate. The production rateof gold nanoparticles using the same laser was up to 3.7 μg/s. The particle size distribution
was obtained from the SEM pictures. Nanoparticle sizes vary from 20 to 125 nm, and mostprobable dimension of the nanoparticles is in the range of 40 to 60 nm.

The 8th International Symposium on Laser Precision Microfabrication

p. 16024-28 April 2007, University of Vienna, Vienna, Austria

P-03
Excimer Laser Processing of CNT Backlight Unit
C.M. Chen1
1

ITRI

Compared to conventional backlight technologies such as CCFF and LED, Carbon NanoTube Backlight Unit (CNT-BLU) have a number of key advantages, including a flatter design,
a lower power consumption, no optical films (i.e. reflectors or diffuser films), and a reduced
cost. Display Technology Center (DTC) of Industrial Technology Research Institute (ITRI) in
Taiwan has developed a novel planar reflective CNT-BLU using a screen-printing method.
The term “planar” here indicates that the cathode and the gate are horizontal with respect tothe anode plane, in marked departure from the conventional “vertical” structure in which thecathode and the gate are vertical with respect to the anode plane. The planar reflective
design keeps higher transmittance for luminescence and reduces the thickness of thebacklight unit. Therefore, it is suitable for use in backlight unit of LCD-TVs. Although screen
printing is a low cost manufacturing technique, its resolution and uniformity are poor.
Therefore, this study will investigate how to apply excimer lasers for processing the carbon
nanotubes on the CNT-BLU emitter. The goal is to control the density and height of the
carbon nanotubes, so that the electrical properties of the emitter can be improved. Screen
printed CNT cathodes were irradiated by KrF (248 nm) excimer laser with fluence from 80 to
150 mJ/cm2. The irradiation was made in air by a single shot for the same spot (see Fig.1).
After laser irradiation, a diode structure was used for electron emission measurement. The
anode was 95Í32 mm2 phosphor patterned on the ITO/glass substrate (see Fig.2). The 300
mm spacer was put between the anode and cathode. The emission characteristics were
measured in a vacuum chamber with a pressure of 10-4 Pa. The emission characteristic isshown in Fig.3. The CNT surface morphology was investigated by scanning electron
microscopes (see Fig.4).

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Fig. 1: Excimer laser processing of CNT

Fig. 3: Field emission

Fig. 2: Image of CNT after laser
irradiation in 150mJ/cm2

Fig.

4:

SEM of CNT after laser
irradiation in 150mJ/cm2

p. 161

The 8th International Symposium on Laser Precision Microfabrication

p. 16224-28 April 2007, University of Vienna, Vienna, Austria

P-04
Laser micro-machining on the single crystal diamond using NdYAG laser
Xiang-Rui Chou1, Jia-Xing Wang1, and Jeng-Shyong Chen1,*
Department of Mechanical Engineering, National Chung Cheng University, Taiwan *Corresponding author Professor Department of Mechanical Engineering National Chung
Cheng University imejsc@ccu.edu.tw

In this work, we report a laser-direct writing method to micro-machine the single crystalline
diamond. We will demonstrated that three-dimensional geometric features with highdimensional accuracy and high material integrity (such as minor thermal damage surface andburr-free surface) on the diamond substrate can be machined using this proposed method.
The diamond is laser ablated as a two-step method. The first step employs a laser-induced
transformation of the crystalline diamond structure to the layered graphite at a temperaturearound 1500K (called the graphitization process) using the laser heat. It is then followed by
the laser-induced sublimation of the layered graphite at a temperature around 4000K (called
the sublimation process). To engineer the laser ablation mechanism of diamond as a reliable
and high precision machining technique, precise control of the laser energy is the criticalpart. The laser energy should be high enough to heat the diamond surface to thegraphitization or sublimation temperature but avoid thermally over-loading on the brittle
diamond substrate. Therefore, a 3-D thermal analysis model has been established to predict
the temperature distribution of the laser machining process. In this thermal analysis model,
the laser energy is modeled as moving and pulsed Gaussian volume heat sources. The timevariant and spatial-variant temperature distribution of the diamond surface is then calculatedby the thermal analysis model. Through the thermal analysis model, the laser irradiancethresholds for the graphitization and sublimation steps were theoretically calculated as 0.367
J/mm2 and 1.105 J/mm2 which had been experimentally verified by about 18% and 3%
errors differed from the 0.45 J/mm2 and 1.14 J/mm2 of experiments. Finally, we will
demonstrate that a diamond micro-nozzle with 3D geometric shape can be fabricated withclean and low HAZ (heat affected zone) surface appearance using the Nd-YAG laser of 170
ns pulse width and 1064 nm wavelength. The laser-treated diamond substrate were
examined by a Raman spectroscopy. The result confirms that the residual graphite layer on
the diamond is not significant. The substrate surface remained as single crystalline diamondstate after the laser processing.

The 8th International Symposium on Laser Precision Microfabrication

p. 16324-28 April 2007, University of Vienna, Vienna, Austria

P-05
DEBRIS-FREE ITO SURFACE MICROFABRICATION USING ANECONOMIC 532nm LASER – VISIBLE LIBWE
Ji-Yen Cheng1, Meng-Hua Yen1,2, Wen-Chih Hsu1, Tai-Horng Young2
1

Research Center for Applied Sciences, Academia Sinica Taiwan
Institute of Biomedical Engineering, National Taiwan University, Taiwan

2

Indium tin oxide (ITO) coated glass has been widely used in optoelectronics because of its
good optical transmission. ITO patterning is usually done by wet chemical etching or
selective ion etching. Photolithography that requires photomask generation and tediousdry/wet etching is needed. In this work a method to achieve debris-free ITO ablation by aneconomic green is presented. ITO is transparent in visible region and hence does not absorb
532 nm laser energy. Laser induced back-side wet etching (LIBWE) has been used for
etching transparent glass substrate but only UV laser has been utilized before. In this work
we utilized our newly developed “visible LIBWE” technology to perform surface
micromachining of ITO thin film by laser direct-writing. No photomask is needed using thislaser direct-writing method. This method can be used for debris-free ITO micropatterning anddevice fabrication, such as microheater and micro flow sensors. Desired surface pattern on
ITO was drawn by AutoCAD and then transferred to a laser machining system for surface
ablation on ITO coated glass. The laser machining system consists of a Q-switched 532 nm
laser and an X-Y CNC stage. 3~10 mW laser power at repetition rate of 2 kHz was used for
ITO ablation. The cleanness of ITO removal was first examined by SEM. Further inspection
on surface element distribution of Indium was observed by energy dispersive X-ray
spectroscopy (EDS). Thermally affected zone (TAZ) is crucial for subsequent application of
the patterned ITO layer. The distortion of the ITO near the ablated region was examined by asurface profiler. TAZ and surface debris resulted by our visible LIBWE was compared to thatfrom UV laser ablation, direct green laser ablation, and near-IR laser ablation. We havealready applied this method for fabricating transparent cell-culturing device.

The 8th International Symposium on Laser Precision Microfabrication

p. 16424-28 April 2007, University of Vienna, Vienna, Austria

P-06
TRANSPARENT CELL CULTURING DEVICE WITH INTEGRATEDHEATER
Ji-Yen Cheng1, Meng-Hua Yen1,2, Wen-Chih Hsu2, Tai-Horng Young2*Research Center for Applied Sciences, Academia Sinica Taiwan**Institute of Biomedical Engineering, National Taiwan University, Taiwan

Real-time observation of cell growth provides essential information for studies such as of cell
migration and chemotaxis. Conventional cell incubation device is usually too clumsy for theseapplications. Here we report a transparent microfluidic device that has integrated heater. ITO
glass was ablated by our newly developed visible LIBWE (laser induced backside wet
etching) so that transparent heater strips were prepared on the glass substrate. A
microfluidic chamber was fabricated by CO2 laser and assembled with the ITO heater so thatthe chamber temperature can be controlled for cell culturing. Successful culturing was
performed inside the device. Continuous long-term observation on cell growth is thusachieved. In this presentation, the development and the performance of the independent cell
culture device is elaborated.

The 8th International Symposium on Laser Precision Microfabrication

p. 16524-28 April 2007, University of Vienna, Vienna, Austria

P-07
Excimer laser assisted growth and dehydrogenation of
Silicon/Germanium thin film multilayers
S.Chiussi, F.Gontad, P.Wójcik, P.González, J.Serra, C.Serra#, B.León
Dpto. Física Aplicada, E.T.S.I.Industriales, Universidade de Vigo, Spain#CACTI,Universidade de Vigo, Spain

The demand of thin amorphous or crystalline Silicon/Germanium layers and alloys with
tailored hydrogen content on micro-patterned as well as on thermo-sensible substrates
implies the development of new processing technologies avoiding high substratetemperatures. Elevated temperatures smudging or destroying the lateral extensions of micropatterned structures on biomedical or nano-electronic devices, softening polymers for flexible
electronic or photovoltaic devices and deteriorating the interface quality of multilayers have to
be avoided. Conventional thermal processing techniques have already demonstrated theadvantages of such SiGe based devices, but are usually of no use when substratetemperatures below 300ºC are needed. It has been shown that an alternative processing
strategy based on UV-Excimer Laser assisted deposition and crystallization techniques cansatisfy these demands and produce high quality SiGe thin films at low substratetemperatures[1]. This contribution presents an integrated UV-Excimer laser assisted processthat combines the growth of thin amorphous hydrogenated Si and Ge multilayers on large
areas as well as in micro-patterned regions with their subsequent in depth controlled
dehydrogenation. Composition of the low temperature grown and laser annealed multilayer
structures have been followed-up through H-Effusion measurements and several
spectroscopic techniques in depth profiling mode for studying both the dehydrogenation
process and segregation effects as a function of the applied laser pulse energy density.
Surface morphology and crystalline structure have been characterized through electron
microscopy and interferometric techniques. The experimental results allowed estimating thetemperature gradient in the multilayer and demonstrating that tailoring of the degree of
dehydrogenation can be achieved through fine control of the laser pulse energy density.
[1]S.Chiussi, E.López, J.Serra, P.González, B.León, Thin Solid Films 508 (2006)48-52

The 8th International Symposium on Laser Precision Microfabrication

p. 16624-28 April 2007, University of Vienna, Vienna, Austria

P-08
Burst pulse ablation of metals and dielectrics using a
Ti:Sapphire femtosecond laser
Jiyeon Choi, Robert Bernath, Troy Anderson, Mark Ramme and Martin Richardson
College of Optics & Photonics CREOL & FPCE, University of Central Florida, Orlando, FL,USA

Femtosecond laser micromachining based on ablative process has potentially many
applications in areas of technology for microelectric devices, micro-fluidics, sensor
technology and for the development of advanced complex devices on a single chip. The low
throughput of femtosecond laser machining because of the shallow penetration depths inmany materials of interest has been a major obstacle against the industrial use although it
has distinct advantages over conventional laser micromachining . A simple method toincrease the ablation rate by increasing the pulse energy soon becomes counterproductive
when the peak intensity exceeds the air ionization threshold. In this paper, we present ourapproach using multiple pulse bursts that can be an alternative to overcome the limit ofincreasing the per-pulse energy. Our prior work on burst ablation has been performed using
high-power lasers at KHz repetition rate and significant increases were observed . We are
now investigating the ablation rates of metals and dielectrics using a custom designed longpath, low frequency Ti:Sapphire oscillator producing bursts of pulse at MHz repetition rates.
These two modalities will then be compared.

The 8th International Symposium on Laser Precision Microfabrication

p. 16724-28 April 2007, University of Vienna, Vienna, Austria

P-09
Pulsed Laser Deposition - UV Lasers and Applications
Ralph Delmdahl, Rainer Pätzel
Coherent GmbH, Goettingen, Germany

Ongoing progress in material research and processing industry is fueled to a large extent by
the technique of pulsed laser deposition (PLD). With this powerful and versatile approach,multi-component target materials can be ablated and deposited onto a substrate to form
stoichiometric layers which exhibit the desired properties. Monitoring of growth parameterssuch as thickness and surface roughness is frequently in-situ monitored via electron
diffraction or other diagnostic tools. High energy excimer lasers lend maximum flexibility to
the PLD technique since virtually every material is amenable to excimer laser ablation andsubsequent deposition on account of their record high photon energies. Spectral properties,
temporal pulse and laser beam parameters of state of the art excimer lasers will becompared with frequency converted flash-lamp pumped Nd:YAG lasers with regard toadvanced pulsed laser deposition requirements.

The 8th International Symposium on Laser Precision Microfabrication

p. 16824-28 April 2007, University of Vienna, Vienna, Austria

P-11
Optimizing and pulse compression of a 200-nJ chirped pulse
Ti:sapphire oscillator
Péter Dombi (1,2) Péter Antal (1) Róbert Szipöcs (1) Júlia Fekete (1) Zoltán Várallyay (3)(1) Research Instiute for Solid-State Physics and Optics, Budapest, Hungary(2) Institut für Photonik, Technische Univerität Wien
(3) FETI Ltd., Budapest, Hungary

Merging Ti:sapphire oscillator technology with the long cavity, chirped-pulse oscillator
concept brought significant advances in recent years. As a result the energy of pulses
directly available from femtosecond oscillators reached several 100s of nJs. Development
efforts to combine this oscillator construction with the cavity dumping technique hold promiseof exceeding the microjoule frontier. State-of-the-art lasers of this type deliver 30-60 fs
pulses. Shorter durations could not be demonstrated due to some inherent limitations in thistechnology that set a boundary to the spectral content of the laser output. In our experiments
we optimized such a laser oscillator by investigating limiting effects (especially intracavity
dispersion) on the width of the laser output spectrum. By optimizing the cavity length as well,
we could achieve pulse energies exceeding 200 nJ at a repetition rate of 3.6 MHz with arelatively compact setup. The inherent lengthening of the outcoupled, highly chirped
picosecond pulses was compensated by a 4-prism compressor to reduce the pulse width tothe transform limit determined by the spectral content of the oscillator output. For anotherapplication we also investigated further extracavity compressibility of the pulses achieved insuch a way. We focussed negatively chirped, 150-fs pulses (generated by overcompensating
the chirp with the 4-prism compressor) in a single-mode fibre with an achromatic objective.
This way optical damage on the fibre input face could be avoided. The resulting fibre output
supercontinuum corresponds to a pulse length of 7-8 fs in the transform-limit. The observed
highly efficient spectral broadening process of negatively chirped pulses in the fibre are also
supported by simulation data.

The 8th International Symposium on Laser Precision Microfabrication

p. 16924-28 April 2007, University of Vienna, Vienna, Austria

P-12
A Monte Carlo Model of Light Propagation in Tissue
Simona Dontu, Sorin Miclos, Dan Savastru, Vasile Babin
National Institute of R&D for Optoelectronics INOE 2000

The Monte Carlo method is rapidly becoming the model of choice for simulating lighttransport in tissue. The paper aims to obtain an analytical model to describe light transport intissue based on Monte Carlo simulation. Flowchart for the variable stepsize simulation is
discussed. The Monte Carlo method began by launching a photon into tissue. Various
techniques are used to reduce the number of required photons to achieve the desired
accuaracy for a Monte Carlo calculation. The convolution equations for finit flat and Gaussian
beams are applied taking into account the internal reflection of photons at boudaries. The
results proved that Monte Carlo method can be efficiently applied for the complex tissue
modeling leading to estimation of reflection, transmission and fluence rates in tissue.

The 8th International Symposium on Laser Precision Microfabrication

p. 17024-28 April 2007, University of Vienna, Vienna, Austria

P-14
Photoresponsive Polymer Structures
M. Farsari, J. Catherine, E. Tsiranidou, S. H. Anastasiadis, M. I. Lygeraki, M. Varda, A.
Athanassiou, C. Fotakis
Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology
Hellas (FORTH), P.O. Box 527, 711 10 Heraklion, Crete, Greece.

A photochromic molecule, spiropyran, has been doped into photopolymers in order toconstruct 2D and 3D structures whose shape, volume and wetting characteristics canreversibly respond to irradiation with light of appropriate wavelength. The reversible
conformational change is induced upon UV laser irradiation, where the embedded non-polar
spiropyran molecules convert to their polar merocyanine isomers; this is reversed upongreen laser irradiation. The construction of 3D structures has been done using multi-photon
polymerization, a powerful technique which allows the fabrication of fully three-dimensional
polymer structures with submicron resolution. The 2D micropatterning of the photochromicpolymer films has been done using soft lithography and visible-light interferometry. It has
been found that surface patterning affects their wettability towards a more hydrophobic ormore hydrophilic behaviour depending on the dimensions of the patterned features and on
the hydrophilicity-hydrophobicity of the substrate. The light-induced wettability variations of
the structured surfaces are substantially enhanced compared to those on uncoated surfaces.
This enhancement is attributed to the photoinduced reversible volume changes of theimprinted gratings, which additionally contribute to the wettability changes due to lightinduced photochromic interconversions.

The 8th International Symposium on Laser Precision Microfabrication

p. 17124-28 April 2007, University of Vienna, Vienna, Austria

P-15
The influence of plasma plume in laser milling for moldmanufacturing
G. Tani1, L. Orazi2, A. Fortunato1, G. Cuccolini2
1

DIEM - Mechanical Engineering Department, University of Bologna. Viale Rosorgimento 2,
40136 Bologna - Italy.
2
DISMI – Department of Science and Methods for Engineering, University of Modena andReggio Emilia. Via Fogliani 1, 42100 Reggio Emilia - Italy.

Laser milling is a manufacturing technology characterized by the possibility of creating small
and complex shapes with good accuracy even in hardened alloys. The short working times, if
compared to the ones concerning EDM, and the possibility to integrate the laser source
directly on the manufacturing system, determined the great interest of today’s industry
towards this technology. The great number of parameters involved in the process makes
optimization quite difficult and time expensive especially if performed through a trial-and-error
technique. According to this the possibility to exploit a reliable and accurate numerical model
to simulate the process is a time and cost-effective topic. This paper deals with the finetuning of a 3D transient numerical model which also takes into consideration the interactionof the plasma plume with the laser beam and the target material. In particular a large numberof simulations were performed aimed at investigating the variation of target materialreflectivity and plasma plume diffusivity with respect to temperature. These physicalphenomena are of basic importance in order to obtain accurate and reliable processsimulations.

The 8th International Symposium on Laser Precision Microfabrication

p. 17224-28 April 2007, University of Vienna, Vienna, Austria

P-16
Characterization of different fiber cleavage methods for
Optimend(TM), a new mechanical splice.
Éric Weynant, Marc Lévesque, Alex Fraser, René Beaulieu, Patrick Zivojinovic
Phasoptx inc. Institut national d'optique (INO)

The use of laser micro machining for fabrication of optical components has grownsignificantly over the past few years. In particular, CO2 lasers have proved their capabilities
for optical fiber cleaving. The roughness of the endfaces obtained by this method is better
than the ones obtained by conventional mechanical cleaving methods and is equivalent tothose obtained by the best mechanical polishing methods. Although laser systems are morecostly and bulky than conventional cleaving devices they have the advantage of being lessoperator and tool dependant which can be and advantage when yield has to be taken into
account. In this article, the two cleaving methods are compared using a new kind of
mechanical splice, OPTIMEND, developed by Phasoptx Inc. The advantages anddisadvantages of the inherently less flat surface of the laser cleaves will be evaluated forboth monomode and multimode fibers. Since this new mechanical splice also allows to autoalign two fibers, fusion splices with a CO2 laser will also be discussed. The results of theselaser splices have been compared with common electric arc fusion splices.

The 8th International Symposium on Laser Precision Microfabrication

p. 17324-28 April 2007, University of Vienna, Vienna, Austria

P-17
Formation of gratings by self-organization of chromium thin filmon the glass substrate under irradiation with laser pulses
Mindaugas Gedvilas, Gediminas Raciukaitis, Kestutis Regelskis and Paulius Gecys
Institute of Physics, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania

In addition to lithography, laser ablation is a typical process of making masks in thechromium layer on the glass substrate. Different types of lasers have been applied tospatially confined evaporation of the metal from the substrate. In this report we present newfeatures in metal removal that were observed when the laser beam was focused into a longand narrow stripe. The infrared Nd:YVO4 laser with the nanosecond pulse duration was usedin experiments. The laser beam was focused through the glass substrate into chromium filmwith the thickness of 50 – 200 nm using an acylindrical lens. The elliptical spot with the
aspect ratio of 1:1000 was formed on chromium in order to remove a strip-like area ofchromium by a laser pulse. The film removal threshold by a single laser pulse was 1.5 J/cm2
for the 100 nm thick layer. Ridges of melted material formed nearby the evaporated area
prevented complete removal of the chromium film with the same fluence. Moreover, thepartially overlapped laser pulses with the fluence up to three times exceeding the thresholdcaused complex self-organization of remaining part of the metal. Formation of regulargratings of ripples was observed in a certain range of laser fluences and beam overlap.
Ripples were orientated perpendicular to the orientation of the beam stripe and their length
increased with every shifted pulse. The periodic gratings with the unlimited line length could
be implemented by using this technique. The grating was irradiated with the HeNe laser andthe diffraction image was investigated. The results showed that the grating period varied
depending on the local laser fluence applied. The grating period linearly changed with thelaser fluence. The grating period slightly decreased with increasing the shift between pulses.
Small period fluctuations caused extension of the non-zero order diffraction maxima in thediffraction image. The period of the chromium grating on the glass substrate can be varied
from 4 to 2.5 μm.

The 8th International Symposium on Laser Precision Microfabrication

p. 17424-28 April 2007, University of Vienna, Vienna, Austria

P-18
Theory of interaction of intense laser radiation with atoms,
nuclei and femto-second laser plasma at surface and atomic
dynamics with non-rectangular laser pulses
Alexander V. Glushkov, Olga Khetselius
Odessa University

At first, QED theory is presented to describe interaction of atoms,nuclei with intense laser
pulses (LP). Method bases on a description of system in field by k-photon emission andabsorption lines moments [1], which are defined within Gell-Mann & Low approach.
Calculation for multi-photon and ATI ionization in H,Na,Mg,Cs is carried out.As example, in
fig.we present multi-photon resonance width for transition 6S-6F in Cs in dependence on LP
intensity I: S- for Lorentz LP; M1, M3, M4-for multi-mode Gauss LP with line band 0.03, 0.08,
0.15 1/cm; M2, M5- for soliton-type LP with line band 0.03,0.15 (+experiment).Atomic
dynamics with non-rectangular LP is studied and results of calculation of population kinetics
of resonant levels for atoms in non-rectangular LP field on basis of the modified Blochequations are presented. The equations describe an interaction of 2-level atom ensembleand LP with account of dipole-dipole interaction. A new result is discovery and adequate
explanation of the optical bi-stability effect. At second, we carried out the modelling of the
femto-second laser plasma (FLP) forming in the porous materials on the basis of the energybalance equations and Green’s function method for non-ordered materials.Using super short
LP changes principally a character of interaction of a laser radiation with surface and may
result in forming FLP. Special attention is surface of which there is a great number of bonds
with H, OH groups. In a case of D-and OD group’s one can wait for realization of cluster
explosion process and reaction D+D-alpha+n (3,8MeV). One can wait for appearance ofpowerful flow of neutrons for LP intensity ~10(16)W/cm2. We carried out modeling excitationof the low lying isomers by means of channels: photoexcitation by X-ray plasma radiation,
electron conversion etc.
1.A.Glushkov etal,Int.J.Quant.Ch.99, 889,936(2004);104,496,512,562(2005);
J.Phys.CS.35,420,425(2006);A.Glushkov,L.Ivanov,Phys.Lett.A 170,33(1992); Nucl.Phys.A
734,e21(2004).

The 8th International Symposium on Laser Precision Microfabrication

p. 17524-28 April 2007, University of Vienna, Vienna, Austria

P-19
A search of possible high power source of monochromatic
gamma radiation and discharge of the metastable nuclei during
negative muon capture
Alexander V. Glushkov
Odessa University

We propose optimal conditions of realization of high power source of monochromatic gamma
radiation. For a sample with a sufficiently high density of metastable nuclei and a sufficiently
intense muon beam the process of discharge of metastable nuclei during negative muon
capture can result in a sharp increase of gamma radioactivity of the sample and may be usedas the basis of operation of a high power source of gamma radiation. A negative muon
captures by a metastable nucleus may accelerate the discharge of the latter by many ordersof magnitude [1,2]. For a certain relation between the energy range of the nuclear andmuonic levels the discharge may be followed by ejection of muon, which may then participate
in the discharge of the other nuclei. We present a new quantitative theory for high power
gasers and discharge dynamics of a nucleus with emission of gamma quantum and further
muon conversion, which initiates this discharge. Within an energy approach [2] the intensitiesof transitions are linked with Im part of energy for the "nuclear core+ proton +muon" system.
Three channels should be taken into account (fig.): 1). Radiative purely nuclear 2j -poledtransition (probability P1); 2). Non-radiative decay, when proton transits to the ground state
and a muon leaves nucle (P2); 3). A transition of proton into the ground state with excitationof muon and emission of gamma quantum (P3). As example we considered the nucleus of
Sc28. The probabilities of decay for different nuclear transitions are: P2(p1/2p3/2)=3,93.10(15),P2(p1/2-f7/2)=3,15.10(12),P2(p3/2-f7/2)=8,83.10(14).
The
dipoletransition 2p-1s occurs with probability: P3=1.9.10(13)1/s. 1. V.I.Gol'dansky,
V.Letokhov,JETP.67,513(1974); L.Ivanov, V.Letokhov, JETP.70,19(1976); A.V.Glushkov,
L.N.Ivanov,Phys.Lett.A 170,33(1992). 2.A.Glushkov etal, Int.J.Quant.Chem. 99, 936(2004);
Nucl.Phys.A. 734, e21 (2004); Rec.Adv.in Theory of Phys.Chem.Syst.15, 301 (2006).

The 8th International Symposium on Laser Precision Microfabrication

p. 17624-28 April 2007, University of Vienna, Vienna, Austria

P-20
New cooperative laser-electron-nuclear effects in atomic andmolecular systems in the strong laser field
Alexander V. Glushkov Svetlana V. Malinovskaya
Odessa University

A great progress in development of laser technique resulted to new class of problems inlaser physics. Great interest attracts the co-operative dynamical phenomena [1] due theinteraction between electron shells and nuclei nucleons in a strong laser field. We propose
new QED theory to calculation the electron satellites in spectra of the electron-nuclear
gamma -transition of nucleus in atoms and molecules. As example, the nuclear transitions in
the isotopes Fe, Ne etc. are considered for O-and F-like ions of Fe, Ne. The electron-nuclear
lines in spectra of emission or absorption can be experimentally observed in plasma of the
O-and F-like multicharged ions. Due to the emission or adsorption of nuclear gammaquantum in molecular system there is changing the electron vibration-rotation molecularstates. We at first develop a new, consistent, quantum theory to calculation of electronnuclear gamma transition spectra (set of vibration satellites in molecule) of nucleus in atomand molecule, based on the energy approach (S-matrix formalism of Gell-Mann and Low) [2].
Decay and excitation probability are linked with imaginary part of the molecule-field system.
Calculation results of the electron-nuclear gamma-transition spectra of nucleus in somemolecular systems are given [2]. A spectrum of emission and adsorption of nucleus 127I
(203keV) in molecule of HI is calculated. As illustration in figure spectrum of emission of
nucleus 127I (E=203keV)in HI is presented ( fig. A is corresponding to the initial state ofmolecule: va=0, Ja=0; fig B ~ va=1, Ja=0).Estimates are made for vibration-nuclear transition
probabilities for sets of molecules: diatomics, 3-atomic XY2, 4-atomic XY3, 5-atomic
XY4(Td), 6-atomic XY3Y2 (D3h), 7-atomic XY6(Oh) ones.
1.L.Ivanov,V.Letokhov, JETP.93,396(1987);V.Letokhov,V.Minogin,JETP.69,1369(1975);
A.Glushkov, L.Ivanov, Phys.Lett.A 170,33(1992);
2. A.Glushkov, S. Malinovskaya, Int. J.Quant. Chem. 99, 889 (2004);104, 513(2005);104,496(2005).

The 8th International Symposium on Laser Precision Microfabrication

p. 17724-28 April 2007, University of Vienna, Vienna, Austria

P-21
Direct writing of polymethyl-methacrylate and polycarbonate
with ultrashort pulses for rapid prototyping applications.
David Gómez, Igor Goenaga
Dpto. de Micro y Nanotecnologías, Fundación Tekniker, Av. Otaola 20, 20600 Eibar(Guipúzcoa), Spain

As it has been commented by many authors, rapid prototyping of polymeric microdevices bymeans of laser direct writing represents clear advantages when compared with cleanroom
technologies, as its flexibility (design can be easily modified), absence of intermediatematerials (silicon, photoresists, etc.) or the easiness to manufacture non-planar geometries.
Femtosecond lasers have overcome the main problems of other laser sources, as
machinability of transparent materials or the appearance of heat affected zones. This way,
manufacturing of polymers with fs-lasers represents an interesting strategy for
microfabrication in an easy, fast and flexible way. However, some fundamental basis of theinteraction of ultrashort pulses with polymers are still poorly understood. As an initial part ofthe present work, the ablation behaviour of two conventional thermoplastics, polymethylmethacrylate (PMMA) and polycarbonate (PC) for femtosecond ultraviolet pulses has been
investigated. As main conclusions, it can be stated that (i) these materials show more
important incubation effect that others (metals, ceramics, glasses, etc.), what drives to aclear broadening of channels as a function of relative motion between the laser and thesample (feedrate) and (ii) a transition between a strong and gentle phase is observed as inmany other kind of materials. A simple model that accounts these effects has been proposed
and width and depth of microchannels parameterised as function of fluence and feedrate.
This characterization has allow the fabrication of some polymeric prototypes in a controlledway (better than +/-2microns) and, after sealing by thermal bonding, transport of small
amount of liquid achieved. In parallel, the writing of waveguides and diffraction gratings in
PMMA and PC have been successfully carried out. Integration of both technology in order tofabricate opto-fluidic devices is currently developed at this moment. Some preliminary results
will be shown.

The 8th International Symposium on Laser Precision Microfabrication

p. 17824-28 April 2007, University of Vienna, Vienna, Austria

P-22
PRODUCTION OF MICRO-PATTERNED AMORPHOUS Si/Ge
BILAYERS AND THEIR CRYSTALLIZATION TROUGH LOW
THERMAL BUDGET LASER ASSISTED TECHNIQUES
F.Gontad, E. López, S. Chiussi, J.Serra, P. González, B. León
Universidade de Vigo

Both amorphous and crystalline SiGe thin films are well established materials for Thin Film
Transistor devices and solar cell applications. However, nowadays the increasing use of
temperature sensible substrates in industrial nano-electronic and photovoltaic devices
discards the applications of conventional processing technologies and promotes the searchand development of new alternative techniques avoiding high substrate temperatures. It has
been shown that the combination of Laser induced Chemical Vapour Deposition (LCVD) andExcimer Laser Crystallization (ELC) is such a satisfactory alternative strategy for obtaining
high quality thin films of those alloys [1]. In this contribution, deposition of nano-patterned
Si/Ge bi-layers and its subsequent crystallization is studied in order to provide singlechamber processing of high quality thin films through a low thermal budget bottom-up
process. Uniform and homogeneous amorphous hydrogenated Silicon and Germanium films
were produced on 3” Si(100) substrates by 193 Excimer Laser induced photolysis of disilane
and germane, through LCVD in parallel configuration as well as micro-patterned Si/Ge bilayers using nano-stencils as masks. Crystallization of the amorphous films was achieved
using ELC and segregation effects of the elements studied for different number of laser
pulses and laser fluences in an inert environment at room temperature. Both laser
techniques, LCVD and ELC, were done using the same Excimer laser in the sameprocessing chamber, providing a high integration of the techniques. Time of flight secondary
ion mass spectrometry in Depth Profiling and scanning modes, X-ray photoelectron
spectroscopy, scanning electron microscopy and atomic force microscopy were used in orderto analyze composition, thickness, surface morphology and crystallinity of as-deposited andcrystallized films.
[1] E. López, S. Chiussi, J. Serra, P. González, B. León, Thin Solid Films, 508 (2006) 48-52

The 8th International Symposium on Laser Precision Microfabrication

p. 17924-28 April 2007, University of Vienna, Vienna, Austria

P-23
Nonlinear optical properties of heavy metal oxide film glasses
produced by pulsed laser deposition
D. Munoz-Martin, J. Gonzalo, H. Fernandez, J. Solis, J.M. Fernandez Navarro
Laser Processing Group, Instituto de Optica, CSIC, Madrid, 28006, Spain

Heavy metal oxide glasses combine high linear (n) and nonlinear (n2) refractive indices witha broad transparency range, which makes them attractive candidates for the production ofactive optical waveguides in the near-mid infrared spectral region. Their optical properties
strongly depend on the glass composition and the presence of ions such as Nb^+5 or Ti^+4
is desirable to enhance the nonlinear optical response. However, compositions having large
heavy metal fractions devitrify or become opals. In this work we have produced transparent
film glasses of the systems: Nb2O5-PbO-GeO2, Nb2O5-PbO-GeO2-Bi2O3 and Nb2O5–
TiO2-TeO2 with large heavy metal fractions by pulsed laser deposition. The compositional
analysis shows that while the oxygen content in the films determines their optical response,
this can be effectively controlled by varying the deposition conditions. The linear opticalproperties of the film glasses have been determined by UV-visible absorption andspectroscopic ellipsometry. The refractive index (n) increases from 2.02 to 2.31, while theoptical energy gap (Eg) decreases from 3.62 to 2.35 eV when increasing the heavy metal
fraction except for glasses containing TeO2. The absorption coefficient is k

The 8th International Symposium on Laser Precision Microfabrication

p. 18024-28 April 2007, University of Vienna, Vienna, Austria

P-24
Optical Near-field Interaction Between Neighboring Micro/Nanoparticles
Z.B. Wang(1), L. Li(1), W. Guo(2), Z. Liu2, P.L. Crouse(1) , David Whitehead(1) , B.S.
Luk'yanchuk(3) , G. Dearden(4), K. Watkins(4)(1)Laser Processing Research Centre, School of Mechanical, Aerospace and Civil
Engineering, University of Manchester, Sackville Street, Manchester, M60 1QD, UK(2)Corrosion and Protection Centre, School of Materials Science, University of Manchester,
The Mill, Manchester M60 1QD, UK (3)Data Storage Institute, DSI Building, 5 Engineering
Drive 1, Singapore 117608, Republic of Singapore (4)Laser Group, Department ofEngineering, University of Liverpool, Brownlow Street, Liverpool L69 3GH, UK

Parallel surface nanopatterning by the enhanced optical near-field under small transparent
particles has been attracted great attention in recent years. The technique offers highproductivity of nano-features on the sample surface based on the near-field ablation, etching,deposition and surface modification. Theoretical investigation of the field distribution was
generally based on single particle models, e.g., Mie theory or Particle on Surface theory, of
which the field interactions between the neighbouring particles have not been well explored.
In this paper, the EM field distribution in the different particle array systems were simulated,
including both mono-layered and multiple-layered particle aggregations. Some new effects,
such as the edge effect of the particle array in which particles situated at the edge of particle
array can produce higher field enhancement under them, has been identified. Experiments
have been carried out to verify the theoretical findings. The influence of the surrounding
medium on the optical near-field interactions is also discussed.

The 8th International Symposium on Laser Precision Microfabrication

p. 18124-28 April 2007, University of Vienna, Vienna, Austria

P-26
Microfluidic waveguides fabricated on glass chips using
femtosecond laser pulses
Fei He, Haiyi Sun, Zenghui Zhou, Ya Cheng and Zhizhan Xu
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine
Mechanics, Chinese Academy of Sciences

We describe the fabrication of microfluidic channel structures on the surface of borosilicate
glass (n=1.516) slide by femtosecond laser direct writing for optical waveguiding application.
Liquid with variable refractive index was filled in the microchannels, serving as the cores of
the waveguides. The waveguide is formed by first scratching a microfluidic channel on glass
surface using focused fs laser beam, which is indicated by the red arrow in Fig. 1a. The endview of the microchannel (in the inset of Fig. 1) shows that the cross section has a width ofapproximately 7μm (measured at the top) and a depth of ~16μm. Then by mixing the two
liquids (paraffin, n=1.474 and α-bromnaphtalene, n=1.658) with different volume proportions,
we created waveguide cores of refractive indices ranging from 1.52 to 1.658. Filling the
microchannel with a liquid of variable refractive index, thus far, generated our microfluidic
optical waveguide. We observed the evolution of the transverse modes in the microfluidic
waveguides using a CCD imaging system. By controlling the refractive index of the liquid in
the microchannel, either multimode or single mode waveguiding can be achieved. Comparedin Fig. 2a and b are a multi-mode pattern generated with a core of n=1.658 and a single
mode pattern generated with a core of n=1.527, respectively. The single mode beam profile
is further plotted in Fig. 2c, showing a symmetric distribution in the horizontal and the verticaldirections. The microfluidic waveguides can potentially be used as an important component
for biosensor application.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Fig. 1: Top view of a 90° arc-shaped
waveguide with radius of curvatureof 5mm on a glass plate. Shown in
the inset is the cross-section of the
waveguide

Fig. 2: SEM image showing themorphology of the internal wallof the microchannel.

Fig. 3: Near field patterns of multi-mode Fig. 4: Near field patterns of single mode
beam
beams

Fig. 5: Beam profile of the single modebeam

p. 182

The 8th International Symposium on Laser Precision Microfabrication

p. 18324-28 April 2007, University of Vienna, Vienna, Austria

P-27
FS-time-resolved phase contrast microscopy in dielectrics
A. Mermillod-Blondin, J. Bonse, R. Stoian*, A. Rosenfeld, I.V. Hertel** * Laboratoire TSI(UMR 5516 CNRS), Université Jean Monnet, 10 rue Barrouin, 42000 Saint-Etienne **Presenting author, also at Freie Universität Berlin, Fachbereich Physik, Germany
Max Born Institute for Nonlinear Optics and Short-Pulse Spectroscopy

The highly nonlinear interaction of femtosecond (fs) laser pulses with transparent materials(glasses) allows the deposition of optical energy into the volume of dielectrics. This gives thepossibility to induce micrometer-sized structural changes, which are associated with local
refractive index changes. For positive refractive index changes, the writing of waveguides
with fs-laser pulses has been demonstrated successfully in many different glasses. However,neither the dynamics nor the processes leading to the local refractive index changes are fully
understood, which prevents an optimum control of the laser-induced modification process.
We have performed time-resolved pump-probe microscopy with sub-micrometer and subpicosecond resolution in order to investigate the temporal and spatial evolution of themodification processes in the volume of fused silica upon irradiation with single fs-laser(pump) pulses at 800 nm wavelength. Optical phase contrast (PC) and the transmission (T)images have been recorded at different delays between the pump and the 400 nm probe
pulses, covering a time span from ~100 fs up to 10 ns. The focus is put here on a range ofpump fluences slightly above the single-pulse threshold of permanent material modification,i.e., close to typical waveguide writing conditions. The observed PC images reveal transientchanges of the local refractive index, whereas the T images can give direct insights into the
dynamics of the laser-generated free-electron plasma. Our results indicate a significant
thermal contribution to the refractive index changes along with strong absorption or
scattering of the probe beam radiation in the focal region which both last for more than 10 ns.
In the temporal delay range between 1 and 10 ns, laser-induced shockwaves are observed
and their spatial propagation has been characterized. These results are discussed on thebasis of recent models of the interaction of fs-laser pulses with dielectrics.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

p. 184

The 8th International Symposium on Laser Precision Microfabrication

p. 18524-28 April 2007, University of Vienna, Vienna, Austria

P-28
Low-debris, efficient laser-produced tin plasma extreme
ultraviolet source for the next generation lithography
Takeshi Higashiguchi, Yusuke Senba, Sumihiro Suetake, Yusuke Sato, Akira Hosotani,
Yukari Takahashi, and Shoichi Kubodera
Department of Electrical and Electronic Engineering and Photon Science Center, Universityof Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki, 889-2192 Japan

Present requirement for the next generation lithography is to develop high average power
EUV light sources at 13.5 nm. Due to the high-power requirement of the EUV emission,
conversion efficiency (CE) from a plasma-heating laser energy to an EUV emission energy
becomes one of the most important parameters. The EUV CE should be optimized bycontrolling plasma parameters, such as the density and temperature of a plasma. The use ofdual laser pulses could realize such a control. Generally speaking, a target with highconcentration produces a high EUV emission energy. Strong self-absorption of the 13.5 nm
emission, however, would become deleterious under high tin concentration, because of an
optically thick plasma nature. In addition to this, a high concentration tin target produces asignificant amount of debris, which causes a serious problem of damaging a set of focusing
optics or condenser mirrors in a vacuum chamber. In contrast to these, a low concentration
tin target would minimize the debris emission and reduce the self-absorption. Our approachis to use a liquid microjet target containing tin nano-particles with a tin concentration as low
as possible to minimize the debris and to reduce the self-absorption. We used a low SnO2
concentration (6%) regenerative liquid microjet target to minimize debris emission and selfabsorption of the 13.5-nm EUV emission. As a result, we demonstrated a low-debris, efficientlaser-produced plasma EUV source. A microjet target with 50 micron diameter containing tin
nanoparticles was formed in a vacuum chamber. The EUV CE increased when the pulse
separation time increased, and reached its maximum of 1.2% at 100 ns. The EUV CE underdual laser pulse irradiation became 3.4 times as large as that under single laser irradiation.
This low Sn concentration made the low-debris emission possible and simultaneously
realized the EUV CE larger than 1%.

The 8th International Symposium on Laser Precision Microfabrication

p. 18624-28 April 2007, University of Vienna, Vienna, Austria

P-29
Quality glass processing using LIBWE method
Huang Zhiqiang, Hong Minghui, Tiaw Kay Siang
Data Storage Institute, Singapore, National University of Singapore, Chartered
Semiconductors Manufacturing

LIBWE is a fast and precise way to etch and create well-defined structures on transparent
substrates. This technique is applied to demonstrate the suitability of using it for high speed
microprocessing of glass. A direct writing approach is used to etch structures directly onto
quartz. A DPSS 3rd harmonic generation Nd:YAG laser with the wavelength of 355nm isused in this study. High speed etching of glass is successfully carried out at a high repetition
rate of 10 kHz and high scanning speed of 100mm/s by a galvanometer. With high speed
processing, the amount of processing time is much reduced. Microfluidic channels are
created within a short time. 3D surface scan shows that they are of good cross-sectional
uniformity. In addition, deposits are observed on the surface of the glass after the laser
processing. XPS analysis further reveals that the nature of this deposit is attributed tocarbon. An isotropic KOH treatment of the surface can remove this layer of deposits. Debris
produced by LIBWE is also removed by laser cleaning, etc. Results from the various cleaning
methods are examined and compared. Various ways to reduce the critical dimension of theetched features and to improve the surface roughness are explored.

The 8th International Symposium on Laser Precision Microfabrication

p. 18724-28 April 2007, University of Vienna, Vienna, Austria

P-30
3D Micro/Nano-structure Fabrication of Phase-change Film
Y. Lin1, 2, 3, M. H. Hong1, 2*, L. S. Tan1, C. S. Lim3, 4, L. P. Shi2, and T. C. Chong1, 2
1

Department of Electrical and Computer Engineering, National University of Singapore, 1
Engineering Drive 3, Singapore 117576
2

Data Storage Institute, DSI Building, 5 Engineering Drive 1, Singapore 117608
3

Nanoscience & Nanotechnology Initiative, National University ofSingapore, 2 Engineering Drive 3, Singapore 117576
4
Department of Mechanical Engineering, National University of Singapore, 2
Engineering Drive 3, Singapore 117576
Laser-crystallized features were produced on initially amorphous phase-change films by
femtosecond laser irradiation through microlens array. It was one high efficient patterning
method since arbitrary features were created uniformly over large area at a short time. Sub100 nm features can be made by using femtosecond laser. The patterned phase-change
films included Ge2Sb2Te5, Sb2Te3, and GeTe films, with 30 nm thicknesses for each one. It
was found that the amorphous and laser-crystallized phase states of different phase-change
films have different reaction to alkaline solution. The different reactions of two phase statesof different phase-change films to alkaline solution were discussed in detail in this paper. 3D
micro/nano-structures, such as holes and bumps, in phase-change films were presented.

The 8th International Symposium on Laser Precision Microfabrication

p. 18824-28 April 2007, University of Vienna, Vienna, Austria

P-32
Micro-drilling of ceramic using pulsed Nd:YAG laser
Elif Kacar, Erhan Akman, Timur Canel, Mesure Mutlu, Levent Candan, Arif Demir, Tamer
Sinmazcelik
University of Kocaeli, Laser Teknologies Research and Application Center, 41380, Umuttepe
Kocaeli TURKEY

Laser micromachining can replace mechanical removal methods in many industrial
applications, particularly in the processing of difficult-to-machine materials such as hardened
metals, ceramics, and composites. It is being applied across many industries –semiconductor, electronics, medical, automotive, aerospace, instrumentation, andcommunications. Laser machining is a thermal process. The effectiveness of this processdepends on thermal properties and, to a certain extent, the optical properties rather than themechanical properties of the material to be machined. Therefore, materials that exhibit a highdegree of brittleness, or hardness, and have favorable thermal properties, such as low
thermal diffusivity and conductivity, are particularly well suited for laser machining.
Percussion laser drilling technology is especially suitable for metal, ceramic,
polyamide/polyamide, polycarbonate, Pyrex, quartz and composite substrates. Laser
machining of ceramics is used extensively in the microelectronics industry for scribing andvia hole drilling.
Rapid improvement of laser technology in recent years gave us facility to control of laserparameters such as wavelength, pulse duration, energy and frequency of laser. Different
combinations of these parameters expand usage of the laser at micro scale. Methot ofmaterial machining by laser is preferred because of the being of clean, rapid and precise. In
this work, we used two different pulsed Nd: YAG laser to determined pulse duration effect.
The first one has minimum pulse duration of 0.5 ms, the other one has pulse duration of 7 ns.
Experiments were done in vacuum environment for preventing oxidation. Diameters of holewere changed between 200 and 350 micron. The micro structures were analyzed using optic
microscope.

The 8th International Symposium on Laser Precision Microfabrication

p. 18924-28 April 2007, University of Vienna, Vienna, Austria

P-34
Laser photoionization method detecting of single atoms andproducts of nuclear reactions
Olga Khetselius
Odessa University

Laser photoionization detecting atoms in a beam and buffer gas attracts great interest forstudying short-lived isotopes and nuclear isomers in experiments in real time of accelerator
work which is used for their generation [1]. We propose new optimal schemes of laser
photoionization method to problem of the nuclear reactions products detecting. It’s studied
the reaction of spontaneous 252Cf isotope fission on non-symmetric fragments, one of that is
Cs nucleus. Usually the foil with implanted Cf ions is disposed before exit of the surface
barrier detector that is sensitive to the nuclear decay fragments. Intensity of the fission
reaction is of order of one event per second. Laser beam crossed the axe of collector of thenuclear fragments. The braking is realized in gas mixture 90% Ar+10% CH4) under pressureof 300 Torr. The heavy fragment of Cf nucleus fission created in ionized track 10(6) electrons
which are collected on the collector. The collector is charged negatively 40mks later after
nuclear decay and 10mks before laser action. The photo electrons, arised due to theselective two-stepped ionization are drafted to proportional counter for detecting. Usually aresonant excitation of Cs is realized by the dye laser pulse , the spectrum of which includes
wavelengths of two transitions 62S1/2-72P3/2 (4555Å) and 62S1/2-72P1/2 (4593Å). Thispulse also realizes non-resonant ionization of Cs excited atoms. We proposed newscheme,which is based on selective resonance excitation of Cs atoms by laser to states nearionization boundary and autoionization decay of excited states under action of electric field[2].In fig. we present the results of modelling for optimal form of laser pulse in scheme fordetecting Cs isotopes: delta pulse + dotted line is optimal form of laser pulse; curves (1) x1
and (2) x2 are populations of ground (6s) and excited (np) states. 1.A.Glushkov,
O.Khetselius et al,Rec.Adv.in Theory of Phys.Chem Syst.15, 285(2006);Nucl.Phys.A
734,21(2004).

The 8th International Symposium on Laser Precision Microfabrication

p. 19024-28 April 2007, University of Vienna, Vienna, Austria

P-35
The generation of ultra-short VUV and X-ray pulses in atomic,
molecular and cluster systems in a strong laser field
Olga Khetselius, Alexander Glushkov, Alexander Fedchuk
Odessa University

Last experimental achievements in field of generating high harmonics of optical radiation
during atomic ionization by powerful femtosecond laser pulses demonstrated a possibility of
construction of the compact sources of VUV radiation (e.g.[1]). We are studying andmodelling generation of the atto-second VUV and X-ray pulses under ionization of the cluster
system in a intense laser field. In ref. [1,2] the results of our modelling the generation of theatto-second VUV and X-ray pulses under ionization of the cluster system molecular system
2D H2+ by femto-second optical pulse have been presented. Modeling is fulfilled within therelativistic scheme of the X&#61474;- scattered waves method. Figure presentes the cluster
Na10 response (our result), the molecular H2+ response for different internuclear distances
2.5, 3.5, 7.4, 16a.u. (data from [1,2]) with smoothed Coulomb potential and atomic (H)response [1] (spectral dependence) under ionization of the system by femto-second opticalpulse. Our calculation show that the generation of the atto-second pulses (the splashes in
fig.2) in cluster system is more effective and profitable (as minimum ~2 orders) than in similarmolecular atomic one. Correspondingly, it has been shown earlier [1,2] that the generation of
the atto-second pulses (the splashes in fig.) in molecular system is more profitable too (asminimum the 1-2 orders) than in similar atomic one. Corresponding spectral dependence of
atomic (atom of H) response is also presented in fig. The effects considered give a hope offurther progress in this direction, especially in work with cluster systems.
1. Emelin M.,Ryabikin M.,Sergeev A. etal,JETP Lett.77, 254 (2003); Fomichev S.,Zaretsky
D.,Bauer D.,Becker W.,Phys.Rev.A.71,013201 (2005).
2. Glushkov A., Khetselius O., Fedchuk A., Sensor Electr. and Micros.Techn. 3,29 (2006);
Photoelectronics 16, 101 (2007); A.Glushkov, O.Khetselius etal, Rec.Adv.in Theory ofPhys.Chem.Syst.15,285(2006).

The 8th International Symposium on Laser Precision Microfabrication

p. 19124-28 April 2007, University of Vienna, Vienna, Austria

P-36
Femtosecond laser microdrilling of Alumina (Al2O3) ceramic
S. H. Kim(1), I. B. Son(2) and S. H. Jeong(1)1. School of Information and Mechatronics, Gwangju Institute of Science and Technology.
2. Advanced Photonics Research Institute, Gwangju Institute of Science and Technology

Ceramic materials like alumina, aluminum nitride, zirconia and so on have attractive physicalproperties. Especially, alumina ceramic (Al2O3) substrates are widely used in electronic
circuits due to their characteristic properties such as high dielectric strength (10 kVmm-1),
good thermal stability and high thermal conductivity (28 Wm-1K-1). Nowadays, the smaller
microelectronic circuits for mobile electronic components or devices are demanded requiring
fabrication technologies for denser circuit patterns, smaller via holes and shorter separation.
However, micromaching of alumina below 100~200µm size using conventional techniques
like mechanical punching, drilling, or cutting faces severe problems such as tool wear andeasy breaking of the workpiece. In this study, the microdrilling of alumna ceramic with goodedge clarity and roundness using a femtosecond laser micromachining system (rep. rate
1kHz, wavelength 785nm, pulse duration 185 fs) is reported. The fabrication of microholes
with sub-hundred micrometer in diameter often results in a poor quality hole due to theaccumulation of sub-microparticles. To avoid the deterioration of hole quality with decreasing
hole size, the condition of blowing air and laser beam interval for repeated ablation arecontrolled. Also, the results when Galvano scan mirror with telecentric lens is used for beamsteering and when translation stages with a stationary objective lens is used for patterning
are compared. Improvement of hole shape and drilling of small through holes are realizedwith process optimization.

Fig. 1: SEM picture of microholes
fabricated in alumina using Galvano
scan mirror system under conditionsof laser energy= 126 µJ, scan speed=1
mm/s, number of scans=50, holediameter= 440µm

Fig. 2: SEM picture of microholes
fabricated in alumina using Galvano
scan mirror system under conditionsof laser energy= 124 µJ, scan speed=1
mm/s, number of scans=60, holediameter= 115µm

The 8th International Symposium on Laser Precision Microfabrication

p. 19224-28 April 2007, University of Vienna, Vienna, Austria

P-37
Influence of Laser Beam Irradiation Condition on Low
Temperature Poly-Silicon Crystallization using a High-power
Diode Pumped Solid State Laser
Dae-Jin Kim, Gun-Seop Go, Hyun-Jung Kim, Seung-Hwan Eum, Gwang-Jae Lee, Doh-Hoon
Kim
Research & Development Center, Kornic Systems, Co., Ltd.

Low temperature polycrystalline silicon (LTPS) technology using a high power laser havebeen widely applied to thin film transistors (TFTs) for liquid crystal, organic light emitting
diode (OLED) display, driver circuit for system on glass (SOG) and static random accessmemory (SRAM). Recent, the semiconductor industry is continuing its quest to create evenmore powerful CPU and memory chips. This requires increasing of individual device speed
through the continual reduction of the minimum size of device features and increasing ofdevice density on the chip. The flat panel display industry also need to be brighter, with richer
more vivid color, wider viewing angle, have faster video capability and be more durable atlower cost. We have developed innovative production tool of laser annealing for low
temperature poly-silicon crystallization using high power diode pumped solid state (DPSS)
laser. This paper introduces the main mechanisms of a laser crystallization using a DPSS
laser and reports the results of a practical line beam laser crystallization method.

The 8th International Symposium on Laser Precision Microfabrication

p. 19324-28 April 2007, University of Vienna, Vienna, Austria

P-40
Nano-patterning by Diffraction Mask-Projection Laser Ablation
Marisa Mäder, Thomas Höche, Jürgen W. Gerlach, Klaus Zimmer, Rico Böhme and Bernd
Rauschenbach
Leibniz Institute of Surface Modification, Permoserstrasse 15, D-04318 Leipzig, Germany

Nanostructures attached to a substrate promise optical and electronic applications (LEDs or
diodes). Moreover, applications for nanodots in various probing techniques (including
Surface Enhanced Raman Spectroscopy) are also aspired. So far, however, the fabrication
process of most nanostructures is still very complex and often too costly for industrial use. An
alternative, versatile, fast, and relatively easy process is laser ablation of a thin film using
diffraction-mask projection. In the latter technique, a pulsed excimer laser (wavelengths 248
nm or 193 nm) is sent through a phase mask. The phase mask modulates the phase of theincident beam and provokes distinct diffraction maxima. Using a Schwarzschild reflection
objective, the resulting interference pattern is demagnified and projected onto a thin film.
When the ablation threshold of the underlying substrate clearly exceeds that of the thin film,
the film is ablated at positions where the intensity is in excess of the ablation threshold of thefilm while the substrate remains unchanged. Different shapes of nanostructures can be
fabricated this way, depending on the pattern of the phase mask. The size of the resulting
structures depends on various parameters like film thickness, material or demagnification.
With this technique, GaN nanowires were produced with a striped mask [1] while Au and Ni
nanodots were fabricated using a checkerboard mask [2]. This technique is in principle
applicabel to every combination of thin film and substrate material, as long as the ablationthreshold of the substrate is high enough in comparison to the film ablation threshold.
[1] Th. Höche, R. Böhme, J.W. Gerlach, K. Zimmer, and B. Rauschenbach Nano Lett. 4[5](2004) 895-897.
[2] Th. Höche, R. Böhme, J.W. Gerlach, B. Rauschenbach, and F. Syrowatka: Philos. Mag.
Lett., 86[10] (2006) 661-667.

The 8th International Symposium on Laser Precision Microfabrication

p. 19424-28 April 2007, University of Vienna, Vienna, Austria

P-41
Microstructure studying of laser pulse irradiating metal targets
in waterM. H. Mahdieh1, A. Chehreghani1, R. Fazeli1, M. Nikbakht1, and B. Gakovic2
12

Department of Physics, Iran University of Science and Technology, Narmak, Tehran, IranInstitute of Nuclear Sciences VINä Atomic Physics Laboratory POB 522, 11001 Belgrade,
SerbiaThe formation of surface-structures by pulsed laser irradiation of metal targets in atmosphericconditions has been interested in recent years because of the wide range of possible
applications [1–4]. The characterization of the topographical evolution of the laser irradiatedregion as a function of the irradiation conditions is very important. The surface morphology of
Ti foils irradiated by long single pulse Nd:YAG in atmospheric air was investigated by Gyorgy
et.al. [5]. It was found that specific laser intensity can produce surface melting without large
liquid displacement or vaporization. The effect of multi-pulse laser irradiation on solid
surfaces was also widely studied in the last years due to its interest from both a physical andtechnological point of view [7-9]. Under the action of the laser pulses, a large variety ofsurface structures develops, such as periodic structures, ridges, volcanic-like craters, cones
or columns [20-24]. Recently, the surface-morphology modification of Ti exposed to multipulse Nd:YAG laser irradiation in air at atmospheric pressure was also reported. They
particularly showed the growth of crown-like structures on the surface of Ti targets [6]. In thispaper microstructure of metal targets irradiated by nanosecond pulsed laser were studied.
The targets were placed in water and irradiated by Nd:Yag (~6 nsec) pulsed laser. In thisexperiment, the targets were exposed to different harmonics of the Nd:Yag laser and theeffects of wavelength on the surface was inspected. The effects of focusing spot, and laser
intensity were also investigated in this experiment. The results show that the crater size, andkerf depends strongly on the laser characteristics.
References:[1] A.M. Prokhorov, I. Ursu, I.N. Mihailescu, V.I. Konov: Laser Heating of Metals (Adam
Hilger, Bristol 1990)[2] W.W.Duley: UV Lasers: Effects and Applications in Materials Science (Cambridge
University Press, Cambridge, UK 1996)[3] I. Ursu, I.N. Mihai

The 8th International Symposium on Laser Precision Microfabrication

p. 19524-28 April 2007, University of Vienna, Vienna, Austria

P-42Light diffraction on modulations of solid surface relief and low
threshold IR multi-photon laser-molecular dissociation on
surface. Laser microscopy
Andrey Malinovsky, Alexander Glushkov, Sergey Ambrosov, Andrey Svinarenko
Odessa University

It well known that the light diffraction on relief of surface can make a significant influence on
dynamics of laser induced reactions, which are taken a place near relief with spatial
modulated profile [1,2]. We present new optimal scheme for isotopic selective low thresholdIR multi-photon dissociation of molecules near surface with periodic relief. There areconsidered possible improvements of so called “Stells” technology. It is carried out modelling
optimal scheme for isotopic selective low threshold IR multi-photon dissociation of molecules
near surface with periodic relief. The physical system is molecular gas (SF6, UF6), that isresonantly excited by the CO2 laser radiation near surface of the periodic Cu lattice. A
definition of local electromagnetic fields and their increasing near surface, contribution of thesurface relief parameters (form, depth etc) are quantitatively taken into account within nonlinear theory of diffraction of limited 2D and 3D light beams on surface with arbitrary discrete
Fourier spectrum of relief [1]. New multi-level model for optimization of excitation ofmolecular gas is considered and definition of optimal form for laser pulse to reach the
maximal effectiveness of laser action in photodissociation process is carried out [2].
Numerical testing of optimized model for molecules of SF6, UF6 is carried out. The obtained
results are used for proposition of a new laser isotope separation scheme with application to
problem of the S and U isotopes separation. At last the modified Letokhov’s scheme ofphotoelectron (photoion) laser microscope is presented (look fig.: 1-needle; 2- adsorbed
macromolecule on the needle surface; 3- fluorescenced screen; 4- source of voltage; 5- laser
beams with frequences w1,w2).
References:
1. V.Letokhov, Laser Spectroscopy, N.-Y., 1997;
2. A.Glushkov,L.Ivanov, J.Phys.B 26,L376(1993); A.Glushkov, A.Malinovsky, etal, Int.J.
Quant. Chem. 104, 562 (2005); J.Struct.Chem. 35, 221 (1998).

The 8th International Symposium on Laser Precision Microfabrication

p. 19624-28 April 2007, University of Vienna, Vienna, Austria

P-43
Estimation of Pulsed Laser Ablated Polyimide Sizes
Nastaran Mansour and *Narges Amiri
Department of Physics, Faculty of Science, Shahid Beheshti University, Evin 1983963113,
Tehran, Iran *Department of Physics, Azad University of Mahalot, Mahalot, IranA thermal model for laser ablation of materials has been proposed. The model includes thedeposition of ablated species in calculation of pulsed laser etch depth. The recession rate of
the surface is calculated based on deposition of ablated materials to the surface due tocollision with the enviromental molecules. The numerical solution of the heat equation withmoving interface, it gives excellent fit to a wide nanosecond pulsed laser ablation
experimental data for polyimide in air. In addition, the ablated polyimide sizes are estimatedusing this model.

The 8th International Symposium on Laser Precision Microfabrication

p. 19724-28 April 2007, University of Vienna, Vienna, Austria

P-44
Pulsed Laser-Induced Surface Modification of Silicon in Liquids
Nastaran Mansour, *Samar Etemad , Rouhollah Karimzadeh and Javid Zamiranvari
Department of Physics, Shahid Beheshti University, Tehran, Iran *Department of Biology,
Shahid Beheshti University, Tehran, IranIn this work, nanosecond pulsed laser-induced surface modification of silicon has been
investigated in water, ethanol and air. Surface irradiation of the samples was carried out
using second-harmonic irradiation of Nd: YAG laser at applied fluence levels of 5-10 J/cm2.
Under water and ethanol confinement, higher surface modification thresholds, lower ablation
depth, and smaller micro spikes spacing were found in comparison to the dry experiments.
The surface roughness and the evolution of its morphology were investigated using AFM and
SEM. This study contributes to a better understanding of the physical processes involved in
the laser ablation of silicon in liquids.

The 8th International Symposium on Laser Precision Microfabrication

p. 19824-28 April 2007, University of Vienna, Vienna, Austria

P-45
Femtosecond laser induced forward transfer (LIFT) process forskutterudite thin film patterning
Marius Dumitru, Marian Zamfirescu, *Anne Daucher, Dan Colceag, Razvan Dabu, Maria
Dinescu
National Institute for Laser, Plasma and Radiation Physics, 409, Atomistilor Str., PO Box MG
36, 077125, Magurele, Bucharest, Romania, Phone: +40-21-4574550,* Laboratoire de Physique des Mate´riaux, UMR CNRS-UHP-INPL 7558, Ecole des Mines,
Parc de Saurupt, F-54042 Nancy Cedex, France

Laser induced forward transfer (LIFT) is a techniques which allows to deposit patterns, spots
and lines with submicron resolution. The thin film which is deposited onto a substratetransparent to the laser wavelength used is transferred by using a single laser pulse onto thereceiving substrate usually placed parallel to the source thin film. The use of LIFT for
patterning of scutterudite material on SiO2/Si substrate using femtosecond pulsed laser isinvestigated in this paper; the importance of CoSb3 (skutterudite) comes from their
thermoelectric properties. A femtosecond pulsed laser (Clark-MXR laser, wavelength:
750nm, pulse width: 150fs), and an MAX341 3-Axis NanoMax, Closed-loop piezo & Stepper
Motors are used for this scope. Thin film of skutterudite deposited by Pulsed Laser
Deposition on fused silica substrate is irradiated with a single laser pulse and transferred on
a SiO2/Si acceptor substrate. Chemical composition and shape aspect of deposited spots
were investigated by electron probe microanalysis (EPMA), Atomic Force Microscopy and
Scanning Electron Microscopy

The 8th International Symposium on Laser Precision Microfabrication

p. 19924-28 April 2007, University of Vienna, Vienna, Austria

P-46
Formation of Graded Band Gap in CdZnTe by Nd:YAG Laser
Radiation
A.Mychko, A.Medvid',P.Onufrijevs, L.Fedorenko
Riga Technical University

Band-gap structures on the basis of CdZnTe are perspective materials for creation of various
semiconductor devices, in particular for highly effective converters of a sunlight, selective
and broadband photo detectors, spectrally scanning lasers with a low threshold current [1].
The aim of this work is investigated an influence of laser radiation on redistribution of Zn
atoms in CdZnTe by photoluminescence (PL) spectra to get further insight into processes
that take place in CdZnTe crystals. The high gradient of temperature, arising at action ofpulse laser radiation nanosecond range, causes redistribution of point defects (vacancies
and interstitial atoms) toward of a temperature gradient. According to the effect, theinterstitial atoms of Cd (Cdi) in Cd1-xZnxTe move along the temperature gradient while theCd vacancies (VCd) and Zn atoms – in the opposite direction, into the bulk of thesemiconductor where temperature is lower. Samples of Cd1-xZnxTe with x=0.06 were usedin our experiments. PL spectra were measured at 5 K using an Ar+ laser for excitation. Afterlaser irradiation of Cd1-xZnxTe crystal with intensity 0.2 MW/cm2 all the lines of PL spectra
start to shift to lower energy of spectra (red shift). In turn, spectral shift of the A°X line at
maximal laser intensity I=2MW/cm2 was 41meV. According to [2] such spectral red shift of
A°X line leads to the decrease of Zn atom average concentration at the irradiated surface of
CdZnTe till 2%. Actually this red shift must be higher, since concentration of impurity atoms
exponentially decreases in the direction from the irradiated surface toward the volume of asemiconductor [3]. We have shown the possibility to form the graded band-gap in Cd1xZnxTe crystal by the second harmonica of Nd: YAG laser radiation. The possibility to form
the graded band-gap in Cd1-xZnxTe crystal by the second harmonic of Nd: YAG laser
radiation have shown. The thermogradient effect has the main role in the redistribution of Zn
atoms at the irradiated surface of Cd1-xZnxTe using Nd:YAG laser second harmonic withintensity from 0.2 MW/cm2 till 2 MW/cm2.
References:[1]. Z. Alferov. Semiconductor, 3-18 (1998)1.
[2]. K. Hielt et.al. Phys. Stat. Sol.(a). 162 (1997) 747.
[3]. A.Medvid’ Defects and Diffusion Forum, 210-212 (2002) 89.

The 8th International Symposium on Laser Precision Microfabrication

p. 20024-28 April 2007, University of Vienna, Vienna, Austria

P-47
Laser-Shaping of Hexagonal Ordered Triangular Gold
Nanoparticles with Nanosecond Pulsed Laser Light
Rodica Morarescu, Frank Hubenthal and Frank Träger
Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology –CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Germany

In order to overcome the classical limits of silicon technology the use of molecular circuits isa challenging new possibility. The idea behind this is to use molecular wires as active
elements and interconnections of devices that perform the basic electronic functions ofrectification, amplification and information storage, thus reducing circuit dimensions to themolecular scale. To realize molecular circuits highly ordered arrays of nanoparticles which
act as anchor points for the uni- and bi-directional molecular wires are necessary. A possible
approach to obtain such regular nanoparticle arrays is nanosphere lithography (NSL) [1].
Depending on the species and length of the molecular wires, the distance between the metal
nanoparticles as well as their size and shape have to be chosen independently. For these
purpose we apply nanosphere lithography in combination with tailoring the dimensions of thenanoparticles with laser light. The latter method has been theoretically modeled andsuccessful applied to noble metal nanoparticles [2]. In this contribution we present recent
results on selective and precise tailoring of triangular gold nanoparticles using ns-pulsed
laser light. The morphological changes have been investigated as a function of laser fluence
and wavelength. In brief, monolayers of triangular gold nanoparticles in a periodic array wereprepared by nanosphere lithography. For this purpose, gold were evaporated through thenanosphere mask. Subsequently, the mask was removed by sonicating the sample in asolvent, leaving behind periodic arrays of triangular gold nanoparticles. The particles havebeen tailored using ns-pulsed laser light choosing different fluences and wavelengths. The
morphological and the accompanying optical changes were investigated by scanningelectron microscopy and extinction spectroscopy. The most important among the numerous
results is a change of the distance between the nanoparticles due to a shape change fromtriangular to oblate. Consequently, we can tune the gap size between the particles fromapproximately 100 nm to 120 nm. Thus, we can adjust the gap size precisely to the length ofthe molecules that should be used as molecular wires. Due to the reshaping of thenanoparticles, we observe an accompanying change in the optical properties, i.e. the surface
plasmon resonance changes from 732 nm after preparation to 532 nm after tailoring withlaser light, depending on the applied fluence. The main advantage of laser irradiation incomparisons to, e.g., thermal annealing is that nanoparticles in a well-defined area of thesample can be addressed. Possible applications of such laser tailored nanoparticles, e.g. as
anchor points for functional molecular wires, will be discussed.
1. C. L. Haynes, R. P. Van Duyne, J. Phys. Chem. B 105, 5599 (2001)
2. F.Stietz, Appl. Phys. A 72, 381 (2001)

The 8th International Symposium on Laser Precision Microfabrication

p. 20124-28 April 2007, University of Vienna, Vienna, Austria

P-48
Fabrication of DOE using Laser Direct Write Lithography System
Sumio Nakahara, Naoshi Ikemoto, Kyoji Matsushima, Shigeyoshi Hisada, Shoso
Shingubara, Takeyoshi Fujita
Dept. of Mechanical Systems Engineering, Kansai University, 3-3-35 Yamatecho, Suita,
Osaka 564-8680, Japan

We fabricated the diffractive optical element (DOE) by the use of the laser direct write
lithography system. Although it is difficult to draw to a large-sized substrate with electronbeam lithography system, since the laser direct lithography system makes it possible,
production of the large DOE is expected. Furthermore, 2 and 4 levels phase-type DOEs were
produced by dry etching processing to the substrate, and comparison of the diffraction
efficiency of the amplitude- and the phase-type DOE was discussed.

The 8th International Symposium on Laser Precision Microfabrication

p. 20224-28 April 2007, University of Vienna, Vienna, Austria

P-49
Direct Laser Marking on CD ROM for Identification
Sumio Nakahara*,**, Shinpei Katou***, Yoshihiro Okino*, Masaaki Takita****, Shigeyoshi
Hisada**, and Takeyoshi Fujita***HRC of Kansai University,**Dept. of Mechanical Engineering, Kansai Univ.,***Graduate school of Kansai University,****Takita Research & Development Co., Ltd.

In order to attempt the direct laser marking on CD ROM medium for identification, laser
machining was carried out against a thin metallic film in the transparent medium using a
microscope with objective lens of NA=0.8 and a turn stage. Heat sources for the processing
were a semiconductor laser excitation YVO4 disk laser (532 nm wavelength of second
harmonic, max 5 W). The medium under consideration on laser marking is an aluminum thinfilm reflector layer, which was sandwiched between a polycarbonate (PC) of 1.2 mm and aprotection film of 5 m thickness. The aluminum thin film (Al) is 100 nm in thickness. The
obtained laser-marking sizes were less than 1 mm and were evaluated using SEM and AFM.
The observation samples inside a transparency resin were obtained by tearing off a
protection film, and the surfaces of the bared PC and protection film were examined. The
surface conditions of laser-marking area were observed.

The 8th International Symposium on Laser Precision Microfabrication

p. 20324-28 April 2007, University of Vienna, Vienna, Austria

P-51
Process of glass-ceramics reverse crystallization under Nd:YAG
laser action
B.Yu. Novikov, V.P. Veiko
St.Petersburg State University of Information Technologies, Mechanics and Optics

Class of glass-ceramics (GC) materials is characterized by low transparent in a visible range
and a polycrystalline structure. It’s possible to change properties of these materials duephase-structure modification. Laser IR irradiation could lead to amorphization of GC
materials like it’s shown in «Nonlinear optical blooming of glass-ceramics under Nd:YAG
laser action» by V.P. Veiko, B.Yu. Novikov (this conference). In addition to this it may bereverse crystalline zones on highly transparent amorphous area under second laser
irradiation at even plase. CO2-laser (10.6 mkm) is used for such kind of transformations
traditionally. In this work reverse crystallization of GC under Nd:YAG laser (1.06 mkm) action
has been investigated on the example of ST-50-1 – the most popular GC material for laser
phase-structure modification. Near-IR radiation highly transparent (and so lowly absorb) inamorphous phase of GC. Because of this some problems under second Nd:YAG laser
radiation treatment is existed. Mechanism and conditions of reverse crystallization, definitionof results and measured characteristics of process will be planed to demonstrate at ourposter.

The 8th International Symposium on Laser Precision Microfabrication

p. 20424-28 April 2007, University of Vienna, Vienna, Austria

P-52
Thin metal sheet bending and residual stresses relaxation by nspulse lasers in MEMS manufacturing
J.L. Ocaña, M. Morales, C. Molpeceres, J.A. Porro, O. García
Centro Láser UPM. Universidad Politécnica de Madrid. Campus Sur UPM. Edificio "La
Arboleda" Ctra. de Valencia, km. 7,3 28031 Madrid. SPAIN

The use of continuous and long-pulse lasers has been previously considered for the bendingof thin metal sheets for MEMS micro components. However, due to the specificallydeveloped long-relaxation-time thermal fields responsible for the bending phenomenon, thefinal sheet deformation state is attained only after a certain reaction time, what, on one side,makes its internal residual stress fields more dependent on ambient conditions and,additionally, may difficult its subsequent assembly process for MEMS manufacturing from thepoint of view of subsequent residual stresses due to adjustment. Partial solutions to these
problems (especially to the second) have been proposed through the use of ultra short laser
pulses. However, although the problem of adjustment residual stresses can be readily solvedin this way, the problem subsists for the bending up to realistic angles (in the order or greaterthan 1 mrad) of metal sheets with thicknesses in the range of 10-100 mm due to the average
power required for a practical process suitability (normally far exceeding the average power
level provided by fs lasers). In this context, the use of ns laser pulses has provided,
according to the authors experience, a really suitable parameter matching for the laser
bending of an important range of sheet components used in MEMS that, preserving the shortinteraction time scale required for the predominantly mechanic (shock) induction of
deformation residual stresses, allows for the successful processing of components in a
medium range of miniaturization but particularly important according to its frequent use insuch systems. In the present paper, an overview is presented on the specific features oflaser interaction in the timescale and intensity range needed for thin sheet micro forming with
ns-pulse lasers along with relevant modelling and experimental results and a primarydelimitation of the parametric space of the considered class of lasers for the referred
processes.

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

p. 205

The 8th International Symposium on Laser Precision Microfabrication

p. 20624-28 April 2007, University of Vienna, Vienna, Austria

P-53
Laser-assisted micromachining of Fe-alloys using a novel
thermochemical etching technique with an optical fiber
Kwang H. Oh, H. D. Im and S. H. Jeong
School of Information and Mechatronics Gwangju Institute of Science and Technology(GIST)

Laser-assisted micromachining technology has been widely applied for the fabrication of
microstructures due to non-contact processing, high resolution, and little limitation inmaterials. In specialty, the laser-assisted etching is a micromachining technique in which alaser beam locally irradiates a workpiece immersed in an etchant to induce thermochemical
reaction between the etchant and the workpiece. Laser-assisted etching is mostadvantageous in the sense that it is a single-step direct writing process requiring no patternmask. Also, in comparison with laser ablation micromachining, it enables fabrication of
microstructures with little heat affected zone and debris as well as high dimensional accuracy
and shape clarity. The conventional lens-based laser etching system, however, requires
many optic components such as a beam expander, a linear polarizer, a waveplate and an
objective lens in order to protect optics on the beam path, and laser system and to tightly
focus on the surface of a workpiece. Accordingly, a complicated laser beam alignment andexposure to the reflected or scattered beam are unavoidable during the etching process. In
this study, a novel laser-assisted etching system utilizing an optical fiber as a machining tool
as well as an optical waveguide is introduced to manufacture metallic grooves and holes.
Complex optic elements are completely replaced by an optical fiber to reduce beam
propagation loss and to simplify the machining system. In the proposed laser-assisted
etching system, a pulsed Nd:YAG laser or a DPSS CW (Nd:YVO4) laser is used as the lightsource to induce thermochemical reaction for groove and hole fabrication. A stainless steel
and an Invar® foil which are representative Fe-alloys are used as the workpiece for process
study. The characteristics of high-aspect-ratio microgrooves and holes concerning process
variables are closely examined. Also, the fabrication and applicability of Invar® shadow maskfor OLED are demonstrated.

Fig. 1: (a) , (b) Top view and (c), (d)cross section of microgroove andmicrohole fabricated utilizing the
proposedlaser-assisted
etchingsystemThe 8th International Symposium on Laser Precision Microfabrication

p. 20724-28 April 2007, University of Vienna, Vienna, Austria

P-54
Aligned Growth of ZnO Nanowire by Catalyst-Free Nano-Particle
Assisted Laser Deposition
Ruiqian Guo, Jun Nishimura, M. Higashihata and Tatsuo Okada
Kyushu University

We have previously succeeded in growing ZnO nanorods and nanowires by a newly
developed nano-particle assisted laser deposition (NPAD). In this report, the well-oriented,
uniquely shaped ZnO nanonails have been vertically aligned to sapphire substrates bycatalyst-free NPAD. The growth mechanism will be discussed, based on the observation of
the growth behavior that has been investigated by variation of the laser ablation time.

The 8th International Symposium on Laser Precision Microfabrication

p. 20824-28 April 2007, University of Vienna, Vienna, Austria

P-55
Formation of Graded Band-gap in CdZnTe by YAG:Nd Laser
Radiation
A.Medvid’1 L.Fedorenko2, B.Korbutjak2, S.Kryluk2, A. Mychko1, P.Onufrijevs1
1Riga Technical University, 14 Azenes Str., LV-1048, Riga Latvia, 2Institute of
Semiconductor Physics NAS of Ukraine, 45 Pr. Nauki, Kyiv, Ukraine

CdZnTe is perspective material for creation of various semiconductor devices, in particularfor highly effective converters of a sunlight, selective and broadband photo detectors,
spectrally scanning lasers with a low threshold current [1,]. Pulse laser radiation is one ofperspective methods of the directed updating electric and recombination properties of ternary
alloy. The given method of processing has localness and short duration of influence on thesemiconductor. A number of papers are devoted to influence of a pulse laser irradiation on
the semiconductor [2, 3]. The purpose of this work is experimental investigation of thepossibility grated band-gap creation in ternary alloy Cd1-xZnxTe. A mechanism for formationof graded band-gap in Cd1-xZnxTe sample using the second harmonic of a Q-switched
YAG:Nd laser radiation (LR) is proposed which involves Thermogradient Effect (TGE).
Results of investigation of the photoluminescence (PL) spectra at 5 K show that theconcentration of atom Zn is increased owing to aggregation of the VCd with Zn after laser
irradiation in the bulk of the sample. 1. The possibility to form the graded band-gap in Cd1xZnxTe crystal by the second harmonic of YAG:Nd laser radiation have shown. 2. The
Thermogradient effect has the main role in the redistribution of Zn atoms at the irradiatedsurface of Cd1-xZnxTe using YAG:Nd laser second harmonic with intensity from 0.2
MW/cm2 till 2 MW/cm2.
References
1. Zh.I.Alferov. Semiconductors.32, (1998) 3-18.
2. A.Medvid’. Defects and Diffusion Forum, 89 (2002)210-212.
3. A.Medvid’, Y. Hatanaka, D. Korbutjak, L. Fedorenko, S. Krilyuk, V Snitka, Appl. Sur. Sc.
197-198 (2002)124-129.

The 8th International Symposium on Laser Precision Microfabrication

p. 20924-28 April 2007, University of Vienna, Vienna, Austria

P-56
Interferometric femtosecond patterning of metals
Kimmo Paivasaari, Jarno Kaakkunen and Timo Jaaskelainen
Department of Physics and Mathematics, University of Joensuu, Finland.

The gratings were ablated to chrome masks using either two- or four-beam interference
pattern. Structures with period around one micrometer were ablated through 100 nm ofchrome using just one femtosecond pulse of 1 mJ energy and 800 nm wavelength. Area ofapprox. 100*100 micrometers of good quality grating were obtained using single pulse. In
figure are shown grating recorded to the chrome mask using two-beam interference. Similar
structures were also made in stainless steel sample using higher number of pulses. The
effect of pulse number and energy to the surface quality were also investigated. Results
show that interferometric femtosecond patterning can provide effective way to manufacture
gratings to the chrome masks and stainless steel moulds.

The 8th International Symposium on Laser Precision Microfabrication

p. 21024-28 April 2007, University of Vienna, Vienna, Austria

P-57
Nano-particle generation from Femtosecond laser ablation ofmaterials
N.Semalteanos, W. Perrie, M.Sharp, S.P. Edwardson and K.G.Watkins
Lairdside Laser Engineering Centre, The University of Liverpool, Wirral CH41 9HP, UK

Ultrashort laser pulse ablation leads to the generation of intense plasmas expanding from asubstrate surface. This highly ionised material, initially at almost solid state density, expands
well after the pulse has been absorbed. and is collisionally cooled by the ambient gas. The
resulting debris returning to the surface consists mainly of spherical nano-particles whose
size distribution depends strongly on the ambient gas composition and pressure. We present
results on the study of nano-particle size distribution and their physical properties (egcrystalline structure) with Ti6Al4V, Si, Alumina and fused silica ablated at 775nm with 180fs
pulselength. For example, in Silicon, the particle size distribution is broad and peaks around
100nm in air while under liquid, the size distribution reduces dramatically with most particles< 50nm in size.

The 8th International Symposium on Laser Precision Microfabrication

p. 21124-28 April 2007, University of Vienna, Vienna, Austria

P-58
Modification of phase change memory materials during
interaction with excimer laser pulses
M. Popescu, F. Sava, A. Lörinczi, G. Socol1, I.N. Mihailescu1
National Institute R&D of Materials Physics, 77125-Bucharest-Magurele,
P. O. Box. MG. 7, Romania
1
National Institute of Lasers, Plasma and Radiation Physics, Bucharest-Magurele,
P. O. Box MG. 6, Romania
Bulk phase change materials of composition GeSb2Te4 and GeSb2Te4 · 10 mol.% SnSe2
have been subjected to excimer laser ablation. A KrF* excimer laser, having the wavelength
λ= 248 nm, with pulse duration τFWHM ≈ 7 ns and 1 Hz repetition rate has been used in theexperiments. A small amount of material from the irradiated area of every sample has been
carefully extracted from the circular crater formed on the surface of the plate subjected toradiation. X-ray diffraction measurements on virgin samples and on the material from theirradiated zones, allowed us to get the fine structural modification determined by theinteraction of the excimer laser pulses with the basical phase change memory materials. The
main effect consists in the vanishing of the crystalline inclusions and transition towards amore homogeneous amorphous phase.

The 8th International Symposium on Laser Precision Microfabrication

p. 21224-28 April 2007, University of Vienna, Vienna, Austria

P-59
Enhancement of sensing properties of thin poly(methyl
methacrylate) films by VUV surface modification(1)I. Raptis, (1)M. Chatzichristidi, (2)E. Sarantopoulou, (2)Z. Kollia(1) Institute of Microelectronics, NCSR ‘Demokritos’ Athens, 15310, Greece(2) Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation,
NHRF Athens, 11635, Greece

Surface modification of polymeric films by light is an efficient method to tailor their properties
and functionality for a variety of applications [1, 2]. VUV irradiation ofPolymethylmethacrylate_(PMMA) thin films deposited on SiO2 layer, demonstrates aconsiderable increase of surface and bulk swelling in comparison to the non irradiated film
areas. AFM images of surface morphology of the irradiated areas reveal that roughness isgreatly enhanced to structures depending on the irradiation conditions. The appearance of
micro- structures and domains of various shapes imply a considerable increase of thepolymeric surface area and volume. Besides morphological changes, VUV, UV visible and IR
absorption spectroscopy of the irradiated and non irradiated areas suggest chemical
modification of the irradiated film areas. Swelling and chemical modification enhances thedetection efficiency of the liquid/gas analytes (water, ethanol, etc) by many orders ofmagnitude. This method can be used to fabricate a polymer based sensor array to engineer
its detection efficiency.
References[1] “Nano-scale spatial control over surface morphology of biocompatible fluoropolymers at
157 nm.” Materials Science and Engineering: C, In Press, E. Sarantopoulou, Z. Kollia, A.C.
Cefalas, A.M. Douvas, M. Chatzichristidi, P. Argitis and S. Kobe.
[2] “Characterization of Polymer Layers for Silicon Micromachined Bilayer Chemical Sensors
Using White Light Interferometry” Sens. Act. B vol. 111-112, pp. 549-554, 2005. D.
Goustouridis, K. Manoli, S. Chatzandroulis, M. Sanopoulou, I. Raptis.

The 8th International Symposium on Laser Precision Microfabrication

p. 21324-28 April 2007, University of Vienna, Vienna, Austria

P-60
MICRO/NANO SELF-ASSEMBLED STRUCTURES FROM BLOCKCOPOLYMER/SAMARIUM-IRON NANOPARTICLES HYBRIDMATERIALS INDUCED BY VUV LIGHT(1)S. Pispas, (1)E. Sarantopoulou, (1)K. Gatsouli, (1)Z. Kollia, (2) S. Kobe
(1) National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48
Vassileos Constantinou Avenue, Athens 11635 Greece. (2) Jozef Stefan Institute,Nanostructured Materials, 1000 Ljubljana, Slovenia

Thin films of block copolymer/samarium-iron metal nanoparticles hybrid organic-inorganic
materials were prepared either by combination of wet chemistry [1], involving metal
nanoparticle formation in block copolymer micellar templates and physical processing via
casting or by spin coating and VUV laser illumination [2] at 157nm. A variety of selfassembled structures in the nanometer to micrometer scale were observed by imaging
techniques, including TEM, SEM and AFM. Investigations show a closely related hierarchy ofthe structures formed in the different length scales. These self-assembled structures hold alarge potential for nanotechnological applications.
References
1. N. Hadjichrisitidis, H. Iatrou, S. Pispas, M. Pitsikalis. J Polym Sci: Part A: Polym Chem, 38,
3211 ( 2000).
2. E. Sarantopoulou, Z. Kollia, A.C. Cefalas Z. Samardzija, S. Kobe Thin Solid Films, V495,
45 (2006)

The 8th International Symposium on Laser Precision Microfabrication

p. 21424-28 April 2007, University of Vienna, Vienna, Austria

P-61
Laser assisted delamination of paint by inductive heating
G.Schuoecker,T.Schumi
Institute of Forming and High Power Laser Technology, TU-Vienna

It has been shown recently, that paint removal from metallic surfaces can be accomplishedby eddy-currents induced in the metal by high frequency magnetic fields due to thedecomposition of the primer located usually between metal and paint. Due to destruction of
the primer the cohesion between paint and metal gets lost and the paint can be removed in
the shape of a solid plates. Nevertheless for practical use the paint must be cut into smaller
pieces. For the latter purpose up to now high pressure water jets have been used. The lattertool is unfavourable due to the large amount of water dispersed on the work piece. Therefore
a new concept has been developed where induction heating is combined with laser cutting or
an appropriate choice of parameters as high frequency power, laser power, cutting gas
pressure and processing speed successful operation could be proved, thus largely improving
the performance of inductive delamination process. Important progress has also be obtained
towards an automatic control of the process based on a temperature measurement.

The 8th International Symposium on Laser Precision Microfabrication

p. 21524-28 April 2007, University of Vienna, Vienna, Austria

P-62
Correction of ditch-shaped defects during KrF excimer laser
ablation using a mask projection
Dongsig, Shin Jahoon, Lee Jeong, Suh Jiwhan, Noh
KIMM (Korea Institute of Machinery and Materials) 171 Jang-dong, Yuseong-gu, Daejeon,South Korea
Using masks for laser ablation has proven useful in the fabrication of prototypes for the
manufacturing of micro-fluidic devices. In this work, an excimer laser was used to engrave
microscopic channels on the surface of polyethylene terephthalate (PET), which showed ahigh absorption ratio for an excimer laser beam with a wavelength of 248 nm. When 50 mm
wide rectangular microscopic channels were made using a 500X500 mm square mask and amagnification ratio of 1/10, ditch-shaped defects were found at both corners. The calculationof the laser beam intensity showed that a coherent image in the PET specimen caused thedefects. An analysis based on the Fourier diffraction theory enabled the prediction of acoherent shape at the image plane, as well as a diffracted beam between the mask and theimage plane. The analysis also showed that the diameter of the aperture was a predominantfactor toward the elimination of ditch-shaped defects in the rectangular microscopic channels
on the PET produced by an excimer laser ablation. * figure explaination: Cross-sectionalview of a nickel replica after electroforming on an ablated PET, with aperture diameters of (a)5 mm, (b) 3mm and (c) 2 mm.

The 8th International Symposium on Laser Precision Microfabrication

p. 21624-28 April 2007, University of Vienna, Vienna, Austria

P-63
Temperature Dependent Heat Generation by Optically Active
Rare Earth Ions for Full Body Cutting of LCD module
Kohei SOGA and Hiroshi MIURA*
Department of Materials Science and Technology, Tokyo University of Science 2641
Yamazaki, Noda, Chiba 278-8510, Japan.
*LEMI, Co., Ltd. 3-10-6 Daikan Yamato-City, Kanagawa 242-0025, Japan.
Recent development of liquid crystal display (LCD) modules requires a simple andinexpensive glass cutting process for the modules in each panel size from a mother glass
sheet sub-assembly, where thin film transistor (TFT) and color filter glass sheets are glued
with a spacing for injecting liquid crystal. The cutting process of the sub-assembly is very
complex and the equipment for the process is expensive, since the TFT and the color filter
glass sheets must be scribed by a diamond chip and are easily broken by pressing columnar
rubber. We are developing a full body cutting (FBC) technology, where the mother glass
sheets sub-assembly are cut all together with heat stress generated a laser light absorption.
In the symposium, we will report three papers on the FBC in by InGaAs laser diode beam tobe absorbed by Yb3+ ions doped in mother glass. The absorbed photon energy is converted
to heat to generate heat stress for the FBC. In this method, the energy of excited electrons
must be relaxed into lattice vibrations (phonon) to generate heat effectively by a process
called multi phonon relaxation (MPR). The purpose of this paper is to find the experimental
conditions for maximum conversion ratio from the optical absorption into the heat formation.
The MPR process can be described by the following equation where the parameters are
relating to electron-phonon coupling, energy separation between the energy level of interestand the next lower one and the dominant phonon energy of the host material. The
parameters are experimentally decided by measuring the temperature dependence offluorescence lifetimes of Yb3+ doped in glass. The temperature dependent heat generation
efficiency was estimated by using the parameters.

The 8th International Symposium on Laser Precision Microfabrication

p. 21724-28 April 2007, University of Vienna, Vienna, Austria

P-65
Laser micro-welding of dissimilar materials using femtosecond
laser pulses
Takayuki Tamaki (a), Tomoyuki Inoue (a), Wataru Watanabe (b), Yasuyuki Ozeki (a), andKazuyoshi Itoh (a)(a) Department of Material and Life Science, Graduate School of Engineering, Osaka
University (b) Photonics Research Institute, National Institute of Advanced Industrial Scienceand Technology

We recently proposed and demonstrated a new laser micro-welding technique based on the
nonlinear absorption of focused ultrashort laser pulses. Because ultrashort laser pulses havevery short duration of time ranging from picosecond to femtosecond, they can have a very
high peak power. When such an intense ultrashort laser pulse is focused at the interface of
two substrates, the intensity in the focal volume can be high enough to cause absorption
through nonlinear processes (multiphoton absorption and tunneling ionization) andavalanche ionization. Through the nonlinear absorption process, the interface of thematerials melts only around the focal spot, and consequently the materials can be locallyjoined by resolidification. Thus, this technique can join transparent materials without
introducing a light-absorbing intermediate layer. An additional advantage of this technique isthat the extremely short pulse avoids the unwanted side effects, such as thermal stress andcracking. Therefore, this technique has potential for welding dissimilar materials that havedifferent coefficients of thermal expansion. In this paper, we present a systematic study on
the micro-welding of dissimilar materials. We demonstrate a welding experiment of polymer
materials that are transparent at the wavelength of the laser radiation. We also demonstratea welding experiment of transparent and absorbing material. We used pairs of dissimilarmaterials, such as polymer and metal, and borosilicate glass and metal. In the experiments,
an amplified femtosecond laser system generating 1-kHz 800-nm 85-fs pulses was used.
The laser pulses were focused at the interface of two materials to be joined. The sample wasmounted on a two-dimensional translation stage. By translating the stage perpendicular tothe optical axis in the two-dimensional plane, we produced an array of small welding region
with rectangular shape. After welding, we performed a simple tensile test in order to measure
the joint str

The 8th International Symposium on Laser Precision Microfabrication

p. 21824-28 April 2007, University of Vienna, Vienna, Austria

P-66
Dynamics of the shock wave accompanied by nanoparticle
formation in the PLA processes
Toshio TAKIYA(1), Naoaki FUKUDA(1), Yasushi IWATA(2) and Minoru YAGA(3)Hitachi Zosen Corporation(1),Advanced Institute of Science and Technology(2),University of the Ryukyus(3)Pulsed laser ablation (PLA) has been used as an effective technique to produce
nanoparticles with a precisely-specified size. Production of nanoparticles with the desired
size is made possible because the conditions for evaporated mass and ambient gas
pressure can be independently controlled in this technique. The interaction between theplume and the ambient gas play an important role in nanoparticle formation. Spectroscopic
experiments have been conducted by other groups with the aim of investigation into theplume dynamics during the PLA process. However, shock waves were generated in the earlystage of the PLA and were resulted to extensive reflection and diffraction of them, whichmakes the clarification of the nanoparticle formation process increasingly difficult. Hitherto,
no attempt to introduce shock wave generation and reflection into the plume dynamics has
been reported in relation to nanoparticle formation. In the present paper, the authors
demonstrate the dynamics of the shock wave relevant to nanoparticle formation by solving
the one-dimensional fluid equation in a flow field generated immediately after PLA in theclosed space between the target and a plate. The classical nucleation theory has certain
effects on the qualitative prediction of nanoparticle formation, although it cannot
quantitatively describe the formation mechanism since it disregards dimerization of theplume-species’ atoms. The existing theory was therefore used in the present calculations
since it provides an efficient method of predicting nanoparticle formation. The light emission
from the plume during the laser ablation process in the closed space was also observed. The
linear plot of the emission strength represented from the results was compared with thecalculation results and some agreements between these results were observed. Thus, it canbe expected that more suitable solutions will be obtained by improving the nucleation modelusing these kind of experimental results.

The 8th International Symposium on Laser Precision Microfabrication

p. 21924-28 April 2007, University of Vienna, Vienna, Austria

P-67
Fabrication of microstructures on cemented tungsten carbide bya femtosecond laser
R. Tanabe, S. Fukami, Y. Ito
Nagaoka University of Technology

Recently, high-precision dies and molds for smaller products are highly required in many
manufacturing fields. Hard die materials, such like cemented carbide, are difficult to machineby cutting tools and the EDM is mainly used. The dies made by these methods need to bepolished after machining. The polishing process takes many laborers and long processing
time. Demands on shorter production time of the dies are ever increasing. The directprocessing of the high-hardness die materials by laser machining is considered to have agreat potential. In this study, a femtosecond laser has been used to machine microstructures
on a plate of cemented tungsten carbide and compared to the results obtained by ananosecond laser. The laser used delivered 100 fs pulses at 785 nm with 1 kHz repetition
rate. Effects of focal position of the femtosecond laser beam are examined: removal rate islarger when it placed before the surface of the specimen. Air-breakdown is observed in thiscase. We consider that heating by the breakdown plasma on the surface might increase theremoval rate. Surface roughness of Ra=0.4μm or less is obtained by 150 μJ pulses at thescanning speed of 0.4mm/s. Only small amount of deposited debris is observed in a groove
machining, while significant amount of debris and re-solidified metal are observed inmachining a small square dent. It is possible, however, to eliminate the re-solidified metal
deposition by optimizing the machining conditions but a thin layer of debris, less than 10 μm
thick, still remains. The thickness of heat affected zone is estimated to be less than 0.5μm,
with no crack or void on the surface. The layer of deposited debris is easily removed bysecond laser irradiation with significantly lower pulse energy. The machined surface has acharacteristic periodic structure with a shorter period than the laser wavelength. Nanosecond
lasers show larger machining rates with larger heat effects compared to the femtosecond
laser.

The 8th International Symposium on Laser Precision Microfabrication

p. 22024-28 April 2007, University of Vienna, Vienna, Austria

P-68
Surface morphology-dependent formation of ripples on Si, SiC,
and HOPG substrates
Takuro Tomita, Ryota Kumai, Keita Kinoshita, Shigeki Matsuo, and Shuichi Hashimoto
Department of Ecosystem Engineering, The University of Tokushima

Laser-induced periodic structures, referred to as “ripples”, have attracted much attention bothfrom fundamental and application-oriented aspects. In particular, the formation process offine ripples, whose period is several times smaller than the wavelength of the irradiated laser
beam, have extensively been studied in recent years. In this paper, we will discuss the effectof initial surface roughness on the formation of fine and coarse ripples. We will also discuss
the cross-sectional profiles of ripples on highly oriented pyrolytic graphite (HOPG). The lightsource used in our experiment was a Ti:Sapphire regenerative-amplifier based on a chirped
pulse amplification system operating at 800 nm (Spectra-Physics, Spitfire). HOPG (HT-MDT
corp.), silicon (Mitsubishi Materials corp.) and single crystal 4H-SiC (Sterling semiconductor
corp.) wafers were used in this experiment. To study the effect of surface roughness andthickness, we prepared different surface morphologies by rubbing the surface of 4H-SiC
wafer with a diamond wrapping film (Imperial, grain size: 1 micron). The surface roughnessof the sample surface was inspected by an atomic force microscope (AFM). The drastic
reduction of the threshold fluence was observed for the fine ripple formation on theroughened surface of 4H-SiC compared with the relatively smooth as-grown surface. This
reduction of the threshold fluence was found only for the fine ripple and not for the coarse
ripple. Based upon this result, we will discuss the reason why the laser pulse duration shorter
than the lattice deformation time is needed to generate the fine ripple structure. The ripple
structures formed on HOPG surface revealed that the cross-section of ripple structure on
HOPG shows the concave shape, while those on Si and SiC show the convex shape. The
detailed discussion of the results will be presented in this conference.

The 8th International Symposium on Laser Precision Microfabrication

p. 22124-28 April 2007, University of Vienna, Vienna, Austria

P-71
Laser Surface Nanotexturing and Applications
Wei Guo(1,2), Lin Li(1), Zhu Liu(2), Zengbo Wang(1) , Philip Crouse(1), David Whitehead(1)(1)Laser Processing Research Centre, School of Mechanical, Aerospace and Civil
Engineering, University of Manchester, Sackville Street, Manchester, M60 1QD, UK(2)Corrosion and Protection Centre, School of Materials Science, University of Manchester,
The Mill, Manchester M60 1QD, UK

Laser surface nanotexturing is very desirable in microelectronics and other applications.
Compared with electron beam and focused ion beam lithography techniques, laser texturing
has an advantage of simple setup, fast speed and massive processing. In this paper, a nearfield technique was developed to overcome the diffraction limit for direct laser surface
nanopatterning. For the first time, it was demonstrated that different nano-features can be
written on the substrates in a large surface area. By using an angular incident laser beamwith a self-assembled particle-lens array, millions of nanostructures can be accomplished bya few laser pulse exposure.

The 8th International Symposium on Laser Precision Microfabrication

p. 22224-28 April 2007, University of Vienna, Vienna, Austria

P-72
Amorphous structure of ripple on SiC studied by micro Raman
spectroscopy
Makoto Yamaguchi [1] Shigeru Ueno [1], Ryota Kumai [2], Keita Kinoshita [2],Takuro Tomita [2], Shigeki Matsuo [2], Shuichi Hashimoto [2][1] Technical Research Institute JAPAN Society for The Promotion of Machine Industry[2] Department of Ecosystem Engineering, The University of Tokushima

Periodic structures, so-called “ripples”, are produced on a solid surface by the irradiation of
femtosecond laser pulses with an energy around the ablation threshold. This structure has
been studied in a wide variety of fundamental and applied research. Although extensive
study has been performed with respect to the formation of femtosecond laser-induced ripple,
less work has been done to reveal the crystalline properties of the ripples.[1] In thisconference, we will report the crystallographic characterization of ripple structures on asingle-crystalline (c-) silicon carbide (4H-SiC) by micro-Raman spectroscopy. The samples
are irradiated with near-infrared femtosecond laser pulses by a Ti: Sapphire regenerative
amplifier system based on a chirped pulse amplification (Spectra-Physics, Spitfire). Pulse
energy, and pulse repetition of the laser used is 0.5-40uJ/pulse, and 50Hz, respectively. The
laser beam is focused onto the sample by a Plano-convex lens (f=100) Renishaw inVia
Raman system in the backscattering configuration is used. Figure shows the Raman spectra
recorded at a fine ripple, coarse ripple, and untreated surface. Sharp peaks (200 cm^-1, 780
cm^-1 and 970 cm^-1) are attributed to the acoustic/optical phonons in c-4H-SiC. At fine andcoarse ripples, three broad band peaks are observed. The bands around 480cm^-1, 880cm^1 and 1500cm^-1 are assigned to amorphous (a-) Si, a-SiC and a-C respectively. Intensity of
a-SiC band at a fine ripple is larger than that at a coarse ripple. These results indicate thatstructural change from c-SiC to a-SiC can be caused at the initial stage of ripple formation,
followed by transformation from a-SiC to a-Si and a-C. The formation process of ripple
structure should be discussed in terms of phase transformation and/or atomic migration
triggered by the interaction between light and material, in addition to the change of surface
morphology such as periodicities.
[1] Appl.Phys.A,79,1429 (2004), F. Costache et al.

The 8th International Symposium on Laser Precision Microfabrication

p. 22324-28 April 2007, University of Vienna, Vienna, Austria

P-73
Tribological property of DLC films with femtosecond-laser
induced nanostructure
Naoki Yasumaru(1), Kenzo Miyazaki(2), Junsuke Kiuchi(3), Kenjiro Komai(1)(1) Fukui National College of Technology,(2) Kyoto University,(3) Eyetec Co., Ltd.

Applications of diamond-like carbon (DLC) films to tribological technology are of growinginterest due to their excellent surface smoothness and low frictional coefficient. In our recent
studies [1-4], we have shown that DLC and TiN film surfaces are structured on a nanometerlevel by irradiating femtosecond (fs) laser pulses. Furthermore, with the Raman spectroscopyof the nano-structured film surface, we have found that the thin DLC film is modified into a
glassy carbon (GC) layer [2]. Here we report tribological properties of the DLC film
(hardness, HV 3000) of which surface has been nanostructured with fs-laser pulses. A broad
area of more than 15 mm x 15 mm on the DLC surface was nanostructured using a precise
target-scan system developed for the fs-laser processing. Friction coefficient of the surfacetreated specimens was measured in air with a ball-on disc friction test machine using balls
made of hardened bearing steel (~ HV 600) and of WC-Co metal (~ HV 1600). We havefound that the frictional properties of DLC film are greatly improved when molybdenum
disulfide layer is coated on the nanostructured surface. For example, the friction coefficient of
DLC surface was observed to decrease down to 0.07 from 0.18 for the steel ball and to 0.02
– 0.04 from 0.08 for the WC-Co ball. On the other hand, a net-like patterning of
nanostructured zone has been shown to increase the friction coefficient of the surface. The
results demonstrate that the tribological property of DLC surface can be controlled with thefs-laser induced nanostructuring.
REFERENCES:[1] N. Yasumaru, K. Miyazaki, J. Kiuchi: Appl. Phys. A, 76 (2003) 983.
[2] N. Yasumaru, K. Miyazaki, J. Kiuchi: Appl. Phys. A, 79 (2004) 425.
[3] K. Miyazaki, N. Maekawa, W. Kobayashi, M. Kaku, N. Yasumaru, J. Kiuchi: Appl. Phys. A,
80 (2005) 17.
[4] N. Yasumaru, K. Miyazaki, J. Kiuchi: Appl. Phys. A, 81 (2005) 933.

The 8th International Symposium on Laser Precision Microfabrication

p. 22424-28 April 2007, University of Vienna, Vienna, Austria

P-74
Femtosecond laser fabrication of metamaterials for highfrequency devices
Marian Zamfirescu*, Razvan Dabu*, Marius Dumitru* George Sajin**, Florea Craciunoiu***NILPRP Bucharest, Atomistilor 409, 077125 Magurele, Romania**IMT Bucharest, Str. Erou Iancu Nicolae 126A, 077190 Bucharest, Romania

Dry etching by femtosecond lasers is used for configuration of micro structures. Films of few
hundreds nm of gold deposited on glass or silicon are precisely processed by tightly focusing
a femtosecond laser with 150fs pulse duration, 775nm wavelength, and energy of hundreds
of nJ. The laser fluence is hold just above the ablation threshold. Thus, the evaporated film
leaves behind structures with thin lateral size of about 1µm, without affecting the substrate.
Using this technique the fabrication of micro devices is demonstrated. The periodic structures
are designed to behave as a left handed metamaterial at a given frequency in the GHz-THz
range. The fabricated metamaterials have applications for antenna, couplers, etc. in the highfrequency range.

The 8th International Symposium on Laser Precision Microfabrication

p. 22524-28 April 2007, University of Vienna, Vienna, Austria

P-75
Ultra-short pulse laser processing of Galium Nitride
semiconductor epitaxial layers: theoretical modeling.
Irina N. Zavestovskaya Oleg.N. Krokhin Peter G. Eliseev
Lebedev Physical Institute of Russian Academy of Science

The processes of the terawatt/cm2-laser irradiation and ablation of the transparent materials
such as nitride semiconductor, sapphire and others are considered theoretically. The power
consumption under the ablation process is described in terms of the nonlinear mechanism of
the tunneling absorption. Laser ablation of the TW/cm2 range laser irradiation is suitable
technique for processing and machining of transparent materials. A comparison of theablation threshold has been performed for different transparent materials under very similar
irradiation conditions. GaN epitaxial layers on the sapphire substrates, sapphire and silicabased glasses are tested. It was determined the laser-induced damage threshold and resultshows the correlation of the LIDT with energy bandgap and other material characteristics.
The threshold appears to grow as about third power of the energy bandgap. The power
consumption under the ablation process of transparent materials is described in terms of theinduced absorption with an effective absorption coefficient of 2.5×104 cm-1. The linear
absorption in GaN at 400 nm is less than 100 cm-1. It means that there is an effective
nonlinear mechanism of the power irradiation absorption in the transparent frequency regionat TW/cm2-range of power density. It is well known from the general theory of the nonlinear
ionization of the atoms and solid materials that the character of the nonlinear ionization undera field action is determined as the intensity I as the irradiation frequency w. The importantparameter of this theory is adiabaticity parameter g. It was shown that if g << 1 (high value ofthe laser power and the case of low frequencies) there is realised the tunneling mechanismof absorption in the electric field. For GaN Eg » 3.43 eV and for I = 40 TW/cm2 g ~ ½ and w= 1015 s-1. It means that for the ablation processes in GaN at terrawatt laser power it isrealized the tunneling mechanism of absorption. Using the dependencies of w we wasdetermined the LIDT dependence on Eg3 which is in good agreement with experimental
results. For other transparent materials parameter g are much smaller than for GaN since thebandgap of GaN is the smallest one. In all the experimental results there realized thetunneling mechanism of ionization. The corresponding increasing of the absorption
coefficient was determined. For GaN we had estimated a about 104 cm-1 that is in good
agreement with the experimental results.

The 8th International Symposium on Laser Precision Microfabrication

p. 22624-28 April 2007, University of Vienna, Vienna, Austria

P-76
The Second-order Doppler Error of Laser Dual-frequency
Interferometer
Zhiping Zhang, Zhaogu Cheng, Zhaoyu Qin and Jianqiang Zhu
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences

Only first-order Doppler frequency shift is considered in present laser dual-frequency
interferometers, however second-order Doppler frequency shift should be considered whenmeasurement corner-cube (MCC) moves at high velocity or variable velocity because it cancause considerable error. The influence of second-order Doppler frequency shift on error ofinterferometer was studied in this paper, and the model of second-order Doppler error was
put forward. Moreover, the model was simulated at high velocity and variable velocity
motionrespectively. The simulated results show that the second-order Doppler error is in
proportion to the velocity of MCC when it moves at uniform motion and the measured
displacement is certain. When the MCC moves at variable motion, the second-order Doppler
error doesn’t only concern velocity but also acceleration. When muzzle velocity is zero thesecond-order Doppler error caused by acceleration of 0.6g can be up to 2.5nm in 0.4
seconds, which is not negligible in nanometer measurement. Moreover, when muzzle
velocity is nonzero, the accelerated motion may result in more error and decelerated motion
may result in less error.

The 8th International Symposium on Laser Precision Microfabrication

p. 22724-28 April 2007, University of Vienna, Vienna, Austria

P-77
Quality and Yield Enhancement of IR-Laser Ablation by
Harmonics Seeding
S.Zoppel (1),(2), G.A.Reider(1)(1) Photonics Institute, Vienna University of Technology,
Gußhausstraße 27-29, 1040 Vienna, Austria(2) Research Centre for Microtechnologies, Vorarlberg University of Applied Sciences,
Hochschulstr. 1, 6850 Dornbirn, Austria

Laser ablation of semiconductors with nano- and picosecond IR sources exhibiting aquantum energy below the band gap is characterized by low ablation rates accompanied bya poor surface quality due to weak absorption. This can be overcome by the use of
frequency converted lasers, at the expense, however, of a considerable energy loss by theconversion process. We present a method which combines high energy efficiency and goodsurface quality by simultaneous irradiation of the sample with a superposition of thefundamental beam (λ=1064 nm) and a small amount of its second (SH) or third harmonic(TH), generated in a thin nonlinear crystal. Conserving the total energy fluence, the highabsorption at the harmonic wavelength leads to an electron population in the conduction
band which is sufficient to start the ablation process by absorption of the IR radiation. In thisfashion, the ablation yield can be increased significantly. In addition, the ablation quality wasdemonstrated to improve in terms of surface smoothness. While the effect is insignificant for
femtosecond laser pulses, it becomes quite efficient for longer pulse durations, where
inexpensive and robust laser sources are easily available.

The 8th International Symposium on Laser Precision Microfabrication

p. 22824-28 April 2007, University of Vienna, Vienna, Austria

List of Authors
Abrusci C. ............................................. Th 4-10
Afonso C. N. .......................................We S2-07
Agarwal A. ........................................... Th S2-11
Akman E. ......................................Fr 9-04, P-32
Ambrosov S. V. .............................P-42, Fr 8-03
Amédée J. .............................................. Fr 7-13
Amiri N. ...................................................... P-43
An J.-Y. .............................................. We 11-02
Anastasiadis S. H. ..................................... P-14
Anderson T. ............................. Th S2-11, P-08
Antal P. ...................................................... P-11
Arai A. .................................................... Fr 9-01
Armas M. ............................................... Tu 4-01
Arnold C. B. ........................................... Th 4-09
Ashkenasi D. .......................................... Fr 9-05
Athanassiou A. ........................................... P-14
Audouard E. .............................. Fr S1-18, P-01,........................................... Th S1-16, We S1-06
Auyeung R. ........................................... Th 4-12Baba Y. .................................................. Fr 7-02
Babin V. ..................................................... P-12
Bachelier G. ........................................ Th S1-15
Bae S. W. .............................................. Th 4-05
Baek K.-Y. .......................................... We 11-02
Baier K. .................................................. Fr 7-03
Barcikowski S. ................ P-02, Fr 7-03, Th 5-02
Bareille R. .............................................. Fr 7-12
Bärsch N. ............................................... Fr 7-03
Bauerfeld F. .......................................We S2-06
Bäuerle D. ...................Fr 7-01, Tu Plenary Talk
Baum A. .............................................. Th S2-15
Baumeister M. ....................................... Th 9-06
Baumert T. ........................................... Th S1-14
Beaulieu R. ................................................ P-16
Bechtold P. .......................................... Th S1-09
Becker P. ...........................................We S2-06
Beer F. ......................................Fr 7-01, Fr 7-04
Bekesi J. ............................................We S3-02
Bellec M. ................................................ Fr 8-01
Bernath R. .................................................. P-08
Besner S. .............................................. Th 5-01
Böhme R. ....................................P-40, We 6-05
Boneberg J. ........................................We S1-05
Bonse J. .............................................. Th S1-15
Bonse, R. .................................................... P-27
Bousquet B. ........................................... Fr 8-01
Brandl V. ............................................We S3-04
Brikas M. .................................................... P-02
Brockmann..........................................We S3-06
Brodoceanu D. ....................................... Fr 7-01
Bruneel D. ............................................Fr S1-18
Campana G. .......................................... Th 9-09
Candan L. .................................................. P-32
Canel T. ..................................................... P-32
Canioni L. ............................................... Fr 8-01
Cárabe J. .............................................. Th 4-07

Carlie N. .............................................. Th S2-11
Castillejo M. . .......................................... Th 4-10
Catalina F. ............................................. Th 4-10
Catherine J. ................................................P-14
Cefalas A. C. ....................... Th 5-04, We 11-03
Chang J.-W. ........................................We 11-02
Charipar N. ............................................ Th 4-12
Chatzichristidi M. ........................................P-59
Chehreghani A. ...........................................P-41
Chen C.M. ..................................................P-03
Chen J.-S. ...................................................P-04
Cheng J.-Y. ....................................... P-05, P-06
Cheng Y. ... P-26, Th 4-11, Th S2-10, We S1-04
Cheng Z. .....................................................P-76
Chichko B. ..................................................P-02
Chichkov B. .........................Th 5-02, We S2-05
Chiussi S. ......................................... P-07, P-22
Choi J. ......................................Th S2-11, P-08
Choi K. H. .............................................. Th 4-05
Chollet C. .................................. Fr 7-06, Fr 7-12
Chong T. C. ..............................P-30, We S2-02
Chou X.-R....................................................P-04
Colceag D. ..................................................P-45
Colina M. ................................................Fr 7-11
Collmer S. ...............................................Fr 9-03
Colombier J. P. .................. Fr S1-18, We S1-06
Combis P. .......................................... We S1-06
Conneely A. ......................................... We 6-01
Costache F. ....................................... We S1-02
Costas ................................................ Th S1-12
Courjaud A. ........................................ We S3-08
Craciunoiu F. ..............................................P-74
Crouse P. L. .......................P-71, Th 5-05, P-24
Cuccolini G. ................................. P-15, Th 9-09
Dabu R. ............................................ P-45, P-74
Daucher A. ..................................................P-45
Dausinger F. ............................ Fr 9-03, Th 9-07
Dearden G. .................................................P-24
Delaigue M. ....................................... We S3-08
Delmdahl R. .............................. P-09, We 11-01
Demir A. ........................................ Fr 9-04, P-32
Denkena B. ...........................................Fr 10-03
Desvergne J-P........................................ Th 4-10
Dickmann K. .......................................... Th 9-06
Dinca V. .................................................Fr 7-07
Dinescu M. .................................... Fr 7-07; P-45
Dodell A. ................................................ Tu 4-01
Dombi P. .....................................................P-11
Dongsig ......................................................P-62
Donnet C. ...................................Fr S1-18; P-01
Dontu S. ......................................................P-12
Draži G. ................................................. Th 5-04
Dumitru M. ........................................ P-45; P-74
Duocastella M. ........................................Fr 7-11
Durrieu M.C. ............................. Fr 7-06, Fr 7-12
Eaton S. M. ......................................... Th S2-13

The 8th International Symposium on Laser Precision Microfabrication

p. 22924-28 April 2007, University of Vienna, Vienna, Austria

Eckert D. ............................................ We S3-07
Edwardson S.P. ..........................................P-57
Eliseev P. G. ...............................................P-75
Englert L. ............................................ Th S1-14
Etemad S. ...................................................P-44
Eum S.-H. ...................................................P-37
Fardel R. .................................................Fr 8-02
Farsari M. ..................................... Fr 7-07, P-14
Faucon M. ...............................................Fr 7-12
Fazeli R. ......................................................P-41
Fechner B. ..........................................We 11-01
Fedchuk A. .................................................P-35
Fedorenko L. ................................... P-46, P-55
Fekete J. .....................................................P-11
Fernandez H. ..............................................P-23
Fernandez Navarro J. M..............................P-23
Fernández Pradas J.M. ..........................Fr 7-11
Fernández-Robledo S. ..........................Th 4-07
Forest B. .....................................................P-01
Forsman A. ............................................Tu 4-01
Fortunato A. ................................. P-15, Th 9-09
Fotakis C. ..................................... Fr 7-07, P-14
Fraser A ......................................................P-16
Fujimori T. ..............................................Th 5-03
Fujita M. ............................................. We S1-07
Fujita T. ............................................. P-48, P-49
Fukami S. ...................................................P-67
Fukuda N. .................................... P-66, Th 4-06
Fukumitsu K. ....................................... Th S2-17
Gakovic B. ..................................................P-41
Gamaly E. ......................................... We S2-01
Gandía J.J. ............................................Th 4-07
Ganser D. .......................................... We S3-03
García O. ....................................................P-52
García-Ballesteros J.J. ..........................Th 4-07
Gaspard S. ............................................Th 4-10
Gatsouli K. ..................................................P-60
Gecys P. .....................................................P-17
Gedicke J. ...............................................Fr 9-02
Gedvilas M. .................................................P-17
Georgiou S. ............................................Fr 7-07
Gerlach J. W. ..............................................P-40
Gillner A. .................................................Fr 9-02
Glushkov A. V. ................... P-35, P-42, Fr 8-03,................................................. P-18, P-19, P-20
Glynn T. ................................................We 6-01
Go G.-S. .....................................................P-37
Goenaga I. ..................................................P-21
Gómez D. ...................................................P-21
Gontad F. .......................................... P-07, P-22
González P. ...................................... P-07, P-22
Gonzalo J. ................................P-23, We S2-07
Gottmann J. ....................................... We S3-03
Grabner G................................................Fr 7-05
Grigoropoulos P. ................................ Th S1-12
Guillemot F. .............................. Fr 7-06, Fr 7-12
Guo R. ........................................................P-54
Guo W. ...............................P-24, P-71, Th 5-05
Haag L. ............................................... Th S1-14

Haglund R. F. ........................................ Tu 4-04
Hahn A. ................................................. Th 5-02
Hanada Y. .............................................. Fr 7-12
Harp Wm. R. ........................................Fr S3-12
Hashimoto S. ....................P-68, P-72, Th S2-18
He F. .......................................................... P-26
Herfurth H. ............................................ Fr 10-01
Herman P. R. ......................................Th S2-13
Herrmann T. .......................................We S2-08
Hertel I.V. ................................. P-27, We S1-06
Higashiguchi T. .......................................... P-28
Higashihata M. ........................................... P-54
Himmelhuber R. .................................We S2-04
Hirata Y. ............................. Th S1-11, Th S2-12
Hisada S. .......................................... P-48, P-49
Ho S. ...................................................Th S2-13
Höche T. ..................................... Fr S1-19, P-40
Holtz R. ................................................ Fr 10-04
Hong M. H. ............................... P-30, We S2-02
Hong S. K. .......................................... We 11-02
Hönninger C. ........................ Fr 8-01, We S3-08
Horn A. ............................... Fr 10-02, We S1-08
Horn-Solle H. ......................................We S3-03
Hosotani A. ................................................. P-28
Howard H. ........................................... We 6-01
Hsu W.-C. ......................................... P-05, P-06
Hu J. ....................................................Th S2-11
Huang Z.Q. .........................................We S2-02
Hubenthal F. .............................................. P-47
Hudek P. ............................................... Th 4-08
Huot N. ................................Fr S1-18, Th S1-16
Hyodo S. ................................................ Fr 7-02
Iba T. ...................................................Th S2-12
Ichihara M. ............................................ Tu 4-03
Ihlemann J. .........................................We S3-02
Ikemoto N. .................................................. P-48
Im H. D. ...................................................... P-53
Inführ R. ................................................. Fr 7-10
Inoue T. ...................................................... P-65
Ishikawa I. .............................................. Fr 7-12
Ito Y. .............................................P-67, Tu 4-03
Itoh K. ......................................................... P-65
Iwata Y. ...................................................... P-66
Izawa Y. ...........................We S1-07, We S1-07
Jaaskelainen T. .......................................... P-56
Jahoon S. ................................................... P-62
Jakopic G. ...........................................Th S2-16
Jarozynski D. .......................................Th S2-15
Jeong L. ..................................................... P-62
Jeong S. H. ...................................... P-36, P-53
Jitsuno T. ................................................ Fr 8-04
Jiwhan S. .................................................... P-62
John ....................................................We S3-01
Johnson Jr. S. L. ................................... Tu 4-04
Jones D. ..............................................Th S2-15
Jordan R. ............................................. We 6-01
Juodkazis S. .....................We S2-01, We S2-03
Kaakkunen J. ............................................. P-56
Kabashin A. V. ...................................... Th 5-01

The 8th International Symposium on Laser Precision Microfabrication

p. 23024-28 April 2007, University of Vienna, Vienna, Austria

Kaçar E. ........................................Fr 9-04, P-32
Kamada H. ............................................ Tu 4-03
Kang H. S. .......................................... We 11-02
Karabay S. ............................................. Fr 9-04
Karimzadeh R. ........................................... P-44
Katayama S. ............................ P-33, We S3-05
Katou S. ..................................................... P-49
Kawahara H. ....................................... Th S2-18
Kawahara T. ....................... Th S1-11, Th S2-12
Kawahito Y. .............................. P-33, We S3-05
Kawai T. ............................. Th S1-11, Th S2-12
Kawano H. ............................................. Fr 7-12
Kawasaki M. ............................. P-33, We S3-05
Khetselius O. ........................... P-34, P-35, P-18
Kim D. S. ............................................... Th 4-05
Kim D.-H. ................................................... P-37
Kim D.-J. .................................................... P-37
Kim D.-Y. ............................................ We 11-02
Kim H. .................................................. Th 4-12
Kim H.-J. .................................................... P-37
Kim J.-W. ........................................... We 11-02
Kim S. H. .................................................... P-36
Kinoshita K. .......................................P-68, P-72
Kiuchi J. ..................................................... P-73
Kiyan R. .............................................We S2-05
Kleinbauer J. ......................................We S3-07
Ko S. H. .............................................. Th S1-12
Kobe S. ...................... P-60, Th 5-04, We 11-03
Kollia Z. ............ P-59, P-60, Th 5-04, We 11-03
Komai K. .................................................... P-73
Komashko A. M. .................................... Tu 4-01
Komatsu S. .......................................... We 6-04
König K. .............................................We S2-06
Korbutjak B. ............................................... P-55
Kramer R. ...........................................We S3-04
Kraus M. ................................................. Fr 9-03
Krokhin O. N. ............................................. P-75
Krolikowski W......................................We S2-01
Kryluk S. ..................................................... P-55
Kubodera S. ............................................... P-28
Kumagai M. ......................................... Th S2-17
Kumai R. ...........................P-68, P-72,Th S2-18
Kumkar M. ..........................................We S3-07
Kuna L. ................................................ Th S2-16
Kunishio K. ............................................ Th 4-06
Kuno K. ............................................... Th S2-17
Lai E. ..................................................We S2-06
Lauzurica S. .......................................... Th 4-07
Lazare S. ..................................Fr 7-06, Th 4-10
Le Guin A ............................................. Fr 10-04
Le Harzic R. .......................................We S2-06
Lee G.-J. .................................................... P-37
Lee J-H. .............................................. Th S2-14
Lee S.-E. ............................................ We 11-02
Leiderer P. .........................................We S1-05
Leising G. ............................................ Th S2-16
León B. ..............................................P-07, P-22
Leschinski C. ........................................Fr S1-19
Lévesque M. .............................................. P-16

Li J. ..................................................... Th S2-13
Li L. .....................................P-24, P-71, Th 5-05
Li R. .................................................... Th S2-10
Liangcai X. ............................................We 6-02
Lim C. S. ...................................P-30, We S2-02
Limpert J. ............................................ Fr S3-09
Lin Y. ........................................P-30, We S2-02
Ling H. ..................................................We 6-03
Lippert T. ................................................Fr 8-02
Liska R. ...................................................Fr 7-10
Liu Z. ...................................P-24, P-71, Th 5-05
López E. .....................................................P-22
Lopez J. ..................................................Fr 7-12
Lorinczi A. ...................................................P-58
Luk'yanchuk B. S. .......................................P-24
Lundgren E. ........................................... Tu 4-01
Lygeraki M. I. ..............................................P-14
M. Tanaka ...............................................Fr 7-02
Ma F. ................................................. We S2-02
Mäder M. ....................................................P-40
Maeshima Y. ..........................................Fr 8-04
Mahdieh M. H. ...........................................P-41
Mai T. A. .............................................. Fr S3-10
Makimura T. ........................................... Th 5-03
Malinovskaya S. V. .....................................P-20
Malinovsky A. V. ........................... P-42, Fr 8-03
Malzer S. ........................................... We S1-03
Manek-Hönninger I. ........................... We S3-08
Mansour N. ....................................... P-43, P-44
Margueritat J. .................................... We S2-07
Märten O. ........................................... We S3-04
Mathews S. ............................................ Th 4-12
Matsuo S. ........................ P-68, P-72, Th S2-18
Matsushima K. ............................................P-48
Mauclair C. ......................................... Th S1-16
McLeod E. ............................................. Th 4-09
Medvid' A. ......................................... P-46, P-55
Meinertz J. ......................................... We S3-02
Mermillod-Blondin A. .................P-27, Th S1-16
Meunier M. ............................................. Th 5-01
Michalowski A. ....................................... Th 9-07
Miclos S. .....................................................P-12
Midorikawa K. ......Fr 7-12, Th S2-10, We S2-09
Mihailescu I.N. ............................................P-58
Mingareev I. ....................................... We S1-08
Minghui H. ..................................................P-29
Misawa H. ........................ We S2-01, We S2-03
Miura H. ......................................................P-63
Miyaji G. .............................................. Th S1-10
Miyamoto I. ....................................... We S2-08
Miyanaga N. ...................................... We S1-01
Miyanishi T. ........................................ Fr S1-17
Miyashita H. ............................................Fr 7-09
Miyatani Y............................................ Th S1-10
Miyazaki K. ................................P-73, Th S1-10
Mizeikis V. ......................................... We S2-01
Mizoshiri M. ........................Th S1-11, Th S2-12
Mlayah A. ........................................... We S2-07
Moalem A. ............................................Fr 10-03

The 8th International Symposium on Laser Precision Microfabrication

p. 23124-28 April 2007, University of Vienna, Vienna, Austria

Moiseev L. ......................................... We S3-03
Molpeceres C. ............................. P-52, Th 4-07
Morales M. .................................. P-52, Th 4-07
Morarescu R. ..............................................P-47
Morenza J.L. ...........................................Fr 7-11
Morita H. ............................................. Th S2-17
Moritz A. .................................................Fr 7-01
Moriyoshi Y. ..........................................We 6-04
Mottay E. ..............................Fr 8-01, We S3-08
Munoz-Martin D. .........................................P-23
Murakami K. ..........................................Th 5-03
Murray D. B. ...................................... We S2-07
Mutlu M. ........................................ Fr 9-04, P-32
Mychko A. ......................................... P-46, P-55
Naeem M. ..............................................Th 9-08
Nagel M. .................................................Fr 8-02
Nakahara S. ...................................... P-48, P-49
Nakahara T..............................................Fr 7-02
Nakamura S. ....................................... Th S2-13
Nakano M. .......................................... Th S2-17
Nakata Y. ........................................... We S1-01
Nakayama S. .........................................Th 4-06
Nedyalkov N. N..................................... Fr S1-17
Neumeister A. .................................... We S2-04
Newaz G. ..............................................Fr 10-01
Niino H. ..................................................Th 5-03
Nikbakh M....................................................P-41
Nishii J. ...............................Th S1-11, Th S2-12
Nishimura J. ................................................P-54
Nishiyama H. ......................Th S2-12, Th S1-11
Noguchi S. ........................................... Fr S3-12
Noh J. ........................................P-62, Th S2-14
Nolte S. ................................................ Fr S3-09
Norimatsu T. ...................................... We S1-07
Novikov B. Y. ............................... P-51, Tu 4-02
Nüesch F. ...............................................Fr 8-02
O’Connor G.M. .....................................We 6-01
Obara M. .............................................. Fr S1-17
Ocaña J. L. .................................. P-52, Th 4-07
Oh K. H. ......................................................P-53
Ohmura E. .......................... Fr S3-12, Th S2-17
Ohta E. .................................................We 6-04
Okada T. ..................P-54, Th S2-18, We S1-01
Okamoto Y. .............................................Fr 9-02
Okino Y. ......................................................P-49
Olowinsky A. ...........................................Fr 9-02
Onodera Y. ............................................Tu 4-03
Onufrijevs P. ..................................... P-46, P-55
Ooie T......................................................Fr 7-02
Ooie T......................................................Fr 7-09
Orazi L. ........................................ P-15, Th 9-09
Ostendorf A. ...................................... We S2-04
Oujja M. .................................................Th 4-10
Ovsianikov A. ..................................... We S2-05
Ozeki Y. ......................................................P-65
Paivasaari K. ..............................................P-56
Pan H. ................................................. Th S1-12
Papazoglou D.G . ................................ Th S1-13
Park H. K. ..............................................Tu 4-04

Partel S. ................................................ Th 4-08
Passinger S. .......................................We S2-05
Pätzel R. ..................................................... P-09
Perrie W. ................................... P-57, Th S2-15
Petit L. .................................................Th S2-11
Piqué A. ................................................. Th 4-12
Pispas S. .................................................... P-60
Popescu M. ................................................ P-58
Porro J. A. .................................................. P-52
Poulikakos D. ......................................Th S1-12
Puerto D. .............................................Th S1-15
Qin Z. ......................................................... P-76
Raciukaitis G. ................................... P-02, P-17
Ramme M. .................................................. P-08
Raptis I. ...................................................... P-59
Rauschenbach B. ....................................... P-40
Regelskis K. ............................................... P-17
Reider G.A. ..................................P-77, Th 4-08
Reif J. .................................................We S1-02
Reinhardt C. .......................................We S2-05
Rethfeld B. ..........................................Th S1-14
Richardson K. .....................................Th S2-11
Richardson M. ........................... P-08, Th S2-11
Richerzhagen B. .................................Fr S3-10
Richter K. ............................................. Fr 10-04
Rode A. ..............................................We S2-01
Rosenfeld A. ............................ P-27, We S1-06
Sajin G. ...................................................... P-74
Sakai T. ................................................Fr S1-17
Sarantopoulou E. ............................ P-59, P-60,..............................................Th 5-04, We 11-03
Sari F. ................................................... Fr 10-02
Sarpe-Tudoran C. ...............................Th S1-14
Sato Y. ....................................... P-28, We 6-04
Satzinger V. .........................................Th S2-16
Sauer D. .............................................We S2-06
Sava F. ....................................................... P-58
Savastru D. ................................................ P-12
Saviot L. .............................................We S2-07
Schirrmacher A. ...................................... Fr 9-05
Schmidt M. ...........................................Th S1-09
Schmidt V. ...........................................Th S2-16
Schoonderbeek A. ............................... Fr 10-03
Schuck H. ...........................................We S2-06
Schumi T. ................................................... P-61
Schuoecker G. ........................................... P-61
Schuster M. ............................................ Fr 7-10
Schwede H. ........................................We S3-04
Scully P. J. ..........................................Th S2-15
Semalteanos N. ......................................... P-57
Senba Y. .................................................... P-28
Serra C. ...................................................... P-07
Serra J. ............................................. P-07, P-22
Serra P. .................................................. Fr 7-11
Sharp M. .................................... P-57, Th S2-15
Shi L. P. .................................... P-30, We S2-02
Shin D. ...............................................Th S2-14
Shingubara S. ............................................ P-48
Shinohara Y. .......................................... Fr 7-02

The 8th International Symposium on Laser Precision Microfabrication

p. 23224-28 April 2007, University of Vienna, Vienna, Austria

Siang T. K. ................................................. P-29
Siegel J. .............................................. Th S1-15
Simon P. ............................................We S3-02
Sinmazçelik T. ........................................ Fr 9-04
Sinmazcelik T. ............................................ P-32
Socol G. ..................................................... P-58
Soga K. ...................................................... P-63
Sohn H. ............................................... Th S2-14
Solis J. ..................................... P-23, Th S1-15
Sommer S. ............................................. Fr 9-03
Son I. B. ..................................................... P-36
Son J.-H. ............................................ We 11-02
Song J. ...............................................We S1-04
Souquet A. .............................................. Fr 7-12
Stampfl J. ............................................... Fr 7-10
Stark M. ..............................................We S2-06
Starovoytova L. ..................................We S3-03
Steyer P. .................................................... P-01
Stoian J. ..................................................... P-27
Stoian R. ..........Fr S1-18, Th S1-16, We S1-06
Stoiber J. ................................................ Fr 7-05
Stollhof J. ...........................................We S3-07
Strassl M. ..................................Fr 7-04, Fr 7-07
Stute U. .............................. Fr 10-03, We S2-04
Suetake S. ................................................. P-28
Sugioka K. ........... Fr 7-12, Th S2-10, We S2-09
Suh J. .................................................. Th S2-14
Sultana T. ............................................ Fr 10-01
Sun H. ...................................... P-26, We S1-04
Sun J. ................................................... We 6-03
Sutter D. H. ........................................We S3-07
Svinarenko A. ............................................. P-42
Szip R. ....................................................... P-11
Takahash Y. ............................................... P-28
Takita M. .................................................... P-49
Takiya T. .................................................... P-66
Tamaki T. ................................................... P-65
Tan L. S. .................................. P-30, We S2-02
Tanabe R. ....................................P-67, Tu 4-03
Tanaka H. ............................................ We 6-04
Tani G. .........................................P-15, Th 9-09
Temme T. ...........................................We S2-04
Tielin S. ................................................ We 6-02
Tokita S. .............................................We S1-07
Tokumura K. .......................................... Fr 8-04
Tomita T. ..........................P-68, P-72, Th S2-18
Träger F. .................................................... P-47
Tsiranidou E. .............................................. P-14
Tsujimoto Y. ........................................... Fr 8-04
Tu J. .....................................................Fr S3-12
Tuennermann A. ..................................Fr S3-09
Turecek C. ............................................. Fr 7-10
Tzortzakis S. ........................................ Th S1-13
Uchida S. .............................................. Th 5-03
Uehara Y. ............................................... Fr 9-01
Ueno S. ...................................................... P-72
Ueta H. ................................................... Fr 8-04
Ulmer F. .............................................Fr S1-19
Uno Y. .................................................... Fr 9-02

Valette S. ....................................................P-01
Várallyay Z. .................................................P-11
Varda M. .....................................................P-14
Varga F. ..................................................Fr 7-10
Varlamova O. .................................... We S1-02
Vasilief I. ............................................ We S3-03
Veiko V. P. ................................... P-51, Tu 4-02
Velten T. ............................................ We S2-06
Verhagen L. ............................................Fr 7-04
Viens J.J. ............................................ Th S2-11
Walter D. ................................................ Th 9-07
Wang G. ................................................ Th 4-11
Wang J.-X....................................................P-04
Wang L. J. ......................................... We S1-03
Wang X. ............................................. We S1-04
Wang Z .B. ..................................................P-24
Wang Z. ..................... P-71, Th 5-05, We S2-09
Watanabe W. ..............................................P-65
Watkins K. ..................................................P-24
Watkins K. G. ............................Th S2-15, P-57
Weiler S. ............................................ We S3-07
Werth A............................................... We S1-08
Weynant É. .................................................P-16
Whitehead D. ......................P-24, P-71, Th 5-05
Wieger V. ................................................Fr 7-01
Wintner E. ................... Fr 7-01, Fr 7-04, Fr 7-07
Wittschie M. ............................................Fr 7-04
Wójcik P. .....................................................P-07
Wokaun A. ..............................................Fr 8-02
Wolf S. ............................................... We S3-04
Wortmann D. ..................................... We S3-03
Xu J. ...................................................... Th 4-11
Xu J. .................................................. We S1-04
Xu N. .....................................................We 6-03
Xu Z. ......... P-26, Th 4-11, Th S2-10, We S1-04
Yaga M. ......................................................P-66
Yamaguchi M. ...........................P-72, Th S2-18
Yasumaru N. ..............................................P-73
Yen M.-H. ......................................... P-05, P-06
Ying Z. ..................................................We 6-03
Yoshino F. ..............................................Fr 9-01
Young T.-H. ...................................... P-05, P-06
Yousif A. .................................................Fr 7-04
Yuhong L. ..............................................We 6-02
Zamfirescu M. ................................... P-45, P-74
Zamiranvari J. .............................................P-44
Zavestovskaya I. N. ....................................P-75
Zehetner J. ............................................ Th 4-08
Zergioti I. ............................................. Th S1-13
Zhang W. ........................................... Th S2-10
Zhang H. ............................................. Th S2-13
Zhang Z. .....................................................P-76
Zhao Q. Z. ......................................... We S1-03
Zhigang C. ............................................We 6-02
Zhiqiang H. .................................................P-29
Zhou Z. ........................................ P-26, Th 4-11
Zhu J. ..........................................................P-76
Zimmer K. ................................... P-40, We 6-05
Zimmerling L.C. .................................. Th S2-11

The 8th International Symposium on Laser Precision Microfabrication
24-28 April 2007, University of Vienna, Vienna, Austria

Zivojinovic P. ..............................................P-16
Zoppel S. ..................................... P-77, Th 4-08

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