bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid Phase Epitaxy Growth and Spectroscopy of Waveguiding Tm3+:CaF2 Thin Films
Authors: Basyrova Liza , Brasse Gurvan , Loiko Pavel , Benayad Abdelmjid , Daniil Gozhalskii , Doualan Jean-Louis , Braud Alain , Camy Patrice
Published: January 2021

Single-crystalline 1.5-5 at.% Tm3+:CaF2 layers (thickness: 20-120 µm) are grown by Liquid Phase Epitaxy. Their structure, absorption, emission and waveguiding properties (propagation losses: <2 dB/cm) are studied. The formation of Tm3+ clusters is evidenced.
Single lateral mode edge-emitting lasers using coupled waveguides
Authors: Dadashi Khalil , Şeker Enes , Demir Abdullah
Published: January 2021

We report on single lateral mode edge-emitting lasers using multimode waveguides. Laterally coupled waveguides are utilized where the higher-order lateral mode is resonantly coupled into an unpumped waveguide to suppress higher-order mode lasing.
Study of influence of defects and impurity centers on visible range luminescence distribution in ZnSe crystals
Authors: Kalinushkin Viktor , Uvarov Oleg , Il’ichev Nikolay , Mirinov Sergey , Studenikin Mikhail , Gavrischuk Evgeniy , Timofeeva Natalia , Gladilin Andrey
Published: January 2021

The influence of defects and impurity on spatial distribution of luminescence (440-725 nm) in ZnSe crystals is studied. It is assumed that the active lasing medium is contaminated with defects formed due to doping process.
Study of marine sediments measured by the LIBS technique (Laser Induced Breakdown Spectroscopy)
Authors: Niang M. , Kongbonga G. Y. M. , Ghalila H. , Majdi Y. , Faye N. A. B. , Chouba L.
Published: January 2021

The accumulation of sediments in the harbours hinders the easy movement of boats. Dredging is a vital activity for the proper operation of harbours. On average, 40 million m3 of sediments are dredged in the harbours of Tunis and 700000 m3 in the harbour of Dakar. Many studies on sediment contamination have revealed high levels of inorganic pollutants due to increasing port activities and their treatments become a major issue for the protection of the environment. The recycling of these sediments is nowadays much regulated and must meet increasingly stringent standards. Thus, a lot of research has been done on the recycling of dredged sediments into building materials. For lower level of pollution they can be reused as embankments. In the case where these levels are too high, they cannot be used as building materials for sanitary reasons and must be discharged offshore, very far from the coast in case of very toxic contamination. Nowadays, it exist several techniques for the analysis and characterization of these sediments, both chemical and physical. Among the physical techniques we have chosen to use the LIBS technique to highlight its promising potential and in particular the possibility of in situ measurements. The main objectives of this study is determining the concentration of heavy metals and comparing them with the regulatory guideline values.
High Peak Power, Non-diffractive and Micro-size Optical Bottles Generation in Bessel Beams
Authors: Rao A Srinivasa , Samanta G K
Published: January 2021

We report on generation of micro-size high peak power optical Bessel bottle beams at 1064 nm wavelength using a single axicon and optical feedback consists of linear optical elements and studied the frequency doubling characteristics.
Pre-chirp managed, circularly polarized Yb-fiber amplifier delivering >100-W, 47-fs pulses using high-dispersion mirrors as compressor
Authors: Zhang Yao , Chen Runzhi , Huang Hangdong , Teng Hao , Fang Shaobo , Wang Junli , Chang Guoqing , Wei Zhiyi
Published: January 2021

We incorporate circularly polarized seeding pulses and high-dispersion mirror compressor into pre-chirp managed amplification and obtain 50-MHz, 47-fs pulses with 101.2-W average power. The efficiency of the pulse compression is >98%.
Spectral Properties of Incoherent Optical Waves Propagating in the Fiber with Normal Dispersion
Authors: Ye Jun , Ma Xiaoya , Zhang Yang , Xu Jiangming , Zhou Pu
Published: January 2021

We numerically and experimentally investigated the propagation of incoherent optical waves in the normal dispersion fiber, and revealed that the unique spectral evolutions were due to the dynamic interplays between dispersion and Kerr nonlinearities.
OPA Based Compact 193 nm Light Source for Hybrid ArF Laser
Authors: Qu Chen , Tanaka Yohei , Igarashi Hironori , Tamaru Yuki , Fuchimukai Atsushi , Murakami Yoshihiko , Miura Taisuke , Kakizaki Kouji
Published: January 2021

We report a 193 nm solid state laser based on 1030 nm laser and 1550 nm laser which is generated by two-stage OPA. 110 mW output power and 0.5 pm spectral width was achieved.
Laser Deposition of Ceramic Particle Reinforced MMC Coating via Four-Quadrant Coaxial-Wire-Feed Laser Cladding Head
Authors: Zhou Shaowei , Mi Gaoyang , Xu Tianyu , Ma Xiuquan
Published: January 2021

Coaxial-wire-feed laser cladding presents clear advantages in economic efficiency, cleanliness and sustainability in manufacturing, based on which a four-quadrant coaxial-wire-feed laser cladding head is designed. Furthermore, the MMC coating is fabricated via this laser head.
Qswitched mode-locked Vortex Laser Formed by Coherent Superposion of Off-axis Traveling Waves
Authors: Lin Yuan-Yao , Hsieh Cheng-Yu
Published: January 2021

Qswitched mode-locking operation was observed in a vortex laser formed by superposition of off-axis resonating traveling waves. When self-modulation is enhanced by pump power dependent relaxation oscillations, QML can be stabilized.
Nonlinear Absorption of Ultrashort High-Intensity Few-Cycle Laser Pulses in Transparent Optical Materials
Authors: Gruzdev Vitaly , Sergaeva Olga
Published: January 2021

Traditional models of nonlinear absorption by optical materials assume single-frequency spectrum of laser light. They are compared against a new Keldysh-type analytical model of nonlinear absorption driven by few-cycle laser pulses with non-zero spectral bandwidth.
Genetic Algorithm Based Reconstruction of Near Field Coherent Synthesis Parameters
Authors: Lemons Randy , Carbajo Sergio
Published: January 2021

We present a method for reconstruction of intensity profiles, and the related near field parameters, generated by coherent synthesis systems using globally optimizing genetic algorithm based on Fourier propagation methods.
CO2 Laser Sidewall Polishing of Millimeter-scale Fused Silica Light Pipes
Authors: Madsen C. K. , Dogan Y. , Lin J.
Published: January 2021

The sidewalls of fused silica light pipes with millimeter-scale cross-sections, having two rough surfaces from etching, were polished using a CO2 laser. Surface profilometry and thermal management were used to achieve optical quality results.
Feasibility Study of the Laser Remelting Process Stability with respect to Initial Surface Topography and Thermographic Monitoring
Authors: Beyfuss Jack , Bordatchev Evgueni V. , Tutunea-Fatan Remus O.
Published: January 2021

Stability of the laser remelting (LRM) process was preliminary studied demonstrating an ability of the high-speed thermographic imaging to monitor the process conditions and estimate variations in the LRM line width.
Statistical Recognition of Laser-Structured Linear Features
Authors: Wu Honghe , Bordatchev Evgueni V.
Published: January 2021

Surface structuring by laser processing is a key technology enabler for a wide range of surface functionalization applications. Statistical recognition of linear geometrical features produced on initially rough surfaces is developed and applied demonstrating reliable analysis of microstructures.
Power Scaling of Single-mode Erbium-doped Alumino-phosphosilicate Fiber Lasers
Authors: Michaud Louis-Charles , Talbot Lauris , Gauvin Frédéric , Boulanger Vincent , Boulé Marc-Antoine , Dubroeucq Romain , Dubuis Simon , Dupont Albert , Gagné-Landmann Anna , Matte-Breton Charles , Ollier Antoine Séverin , Grégoire Nicolas , Morency Steeve , Messaddeq Younès , Bernier Martin
Published: January 2021

We report the highest power achieved to our knowledge for an ytterbium-free alumino-phosphosilicate co-doped erbium fiber laser with 51W of output power. We will also discuss on the 100W-level power scaling potential of such laser.
Efficient all-PM-fiber Mamyshev oscillator based on fiber Bragg gratings
Authors: Boulanger Vincent , Olivier Michel , Trépanier François , Bernier Martin , Piché Michel
Published: January 2021

We report an all-polarization-maintaining-fiber femtosecond Mamyshev oscillator delivering 31 nJ pulses with an efficiency of 32%. This self-polarizing oscillator is based on fiber Bragg gratings acting as filters and pump reflector.
Tunable carrier-envelope phase-stable attosecond pulse generation by Thomson scattering of intense terahertz pulses
Authors: Gyöngy András , Tibai Zoltán , Hebling János , Tóth György
Published: January 2021

Thomson scattering of intense terahertz pulses was investigated to generate nJ-level tunable carrier-envelope phase-stable single-cycle attosecond pulses.
1.9 mW XUV source by cascaded harmonic generation from an Yb:fiber laser
Authors: Comby A. , Descamps D. , Beauvarlet S. , Gonzalez A. , Guichard F. , Petit S. , Zaouter Y. , Mairesse Y.
Published: January 2021

We demonstrate high XUV photon fluxes by producing high-order harmonics from a turnkey femtosecond Yb-doped amplifier. We thus show efficient XUV generation with 1.9 mW average power at 18 eV.
Soft x-ray high order harmonic generation from high power ultrafast thulium-doped fiber lasers
Authors: Gebhardt M. , Heuermann T. , Gaida C. , Wang Z. , Lenski M. , Klas R. , Kirsche A. , Liu C. , Hädrich S. , Jauregui C. , Rothhardt J. , Limpert J.
Published: January 2021

We report on soft x-ray HHG driven by a thulium-doped fiber laser. It is the first time that a photon energy cut-off ~400 eV has been demonstrated using this highly scalable laser technology.
Laboratory characterization of soft X-ray optics
Authors: Probsta Jürgen , Löchela Heike , Braigb Christoph , Seifertb Christian , Erkob Alexei
Published: January 2021

We report on the construction and operation of the laboratory-scaled soft X-ray reflectometer at the Institute of Applied Photonics e.V. in Berlin. With a µ m-sized source and flexible high-precision mechanics, the competitive capabilities range from the determination of diffraction efficiencies for variable line space gratings to the characterization of mirrors by an evaluation of the emitted wave front.
Time delay compensating monochromator based on reflection zone plates
Authors: Erko Alexei , Braig Christoph
Published: January 2021

We present the sequential combination of two identical reflection zone plates (RZPs) placed in opposite orders of diffraction (+1st and −1st). The scheme compensates for the time elongation of monochromatized (E/∆E ≲ 500), femtosecond (fs) soft X-ray pulses with an energy E ~ (0.1 − 1) keV down to ≈ 10 fs or less.
Attosecond parametric pulse amplification in high order harmonic generation far from the ionization threshold
Authors: Serrat C. , Seres J. , Seres E. , Dinh T-H. , Hasegawa N. , Nishikino M. , Namba S.
Published: January 2021

We present first principles calculations of parametric amplification of attosec-ond coherent pulses around 100 eV at the single-atom level in high order harmonic generation from excited states of He+ and compare them with experimental measurements. Our results indicate the basic physics to achieve the desired attosecond XUV gain in the spectral regions far from the ionization threshold of the considered interacting media.
Circularly-Polarized Harmonic Generation in Underdense Plasma Using Bi-Color Lasers
Authors: Chitgar Zahra M. , Gibbon Paul
Published: January 2021

We have modeled bi-color circularly polarized harmonic generation in under-dense plasmas using a combination of PIC simulation and a nonlinear fluid model. Generalized selection rules and helicities, together with harmonic efficiencies are predicted and found to be consistent with numerical results.
Impure infrared vortex driven high harmonic generation
Authors: Pandey A. K. , Sanson F. , Guilbaud O. , Papagiannouli I. , Harms F. , Dovillaire G. , Baynard E. , Demailly J. , Lucas B. , Neveu O. , Pittman M. , Ros D. , Richardson M. , Johnson E. , Li W. , Balcou Ph. , Kazamias S.
Published: January 2021

We demonstrate that high harmonic generation when driven by vortex driver contaminated with various orbital angular momentum (OAM) modes, the upconverted EUV harmonic deviates from perturbative conversion law to exhibit a spectrum of OAM orders.
X-ray Sources from Self-modulated Laser Wakefield Acceleration: Applications in High Energy Density Sciences
Authors: Albert F. , Lemos N. , King P.M. , Shaw J. L. , Milder A. L. , Goyon C. , Kalantar D. , Remington B. , Ose N. , Alessi D. , Prantil M. , Marsh K. A. , Pollock B. B. , Pak A. , Saunders A. , Hartemann Fred V. , Wu Sheldon S. Q. , Falcone R. , Hegelich B.M. , Moody J. D. , Glenzer S. H. , Michel P. , Joshi C.
Published: January 2021

This work discusses the development of x-ray and gamma-ray sources based on laser-wakefield acceleration (LWFA) in the self-modulated regime. These sources are developed for probing high energy density (HED) science experiments at large-scale laser facilities.
XPulse: Towards a Laser-driven X-ray imaging system
Authors: de La Rochefoucauld Ombeline , Barbrel Benjamin , Piponnier Martin , Mastropietro Francesca , Oudjedi Laura , Palussière Jean , Kantor Guy , Courjaud Antoine , Harms Fabrice , Bakkali Aboubakr
Published: January 2021

The XPulse project aims to develop an innovative X-ray phase contrast mammographic system based on the use of laser plasma X-ray source. The demonstration of feasibility is at the heart of this presentation.
High-order Harmonic Generation in Femtosecond Laser Micromachined Microfluidic Glass Devices for Ultrafast X-ray Spectroscopy
Authors: Ciriolo A. G. , Vázquez R. Martínez , Crippa G. , Tosa V. , Frezzotti A. , Faccialà D. , Devetta M. , Osellame R. , Vozzi C. , Stagira S.
Published: January 2021

We report efficient high harmonic generation and control in glass devices fabricated by femtosecond laser micromachining. This work paves the way to microfluidic HHG beamlines for X-ray spectroscopy with attosecond resolution.
ColdLight: From Laser-Cooled Atoms to Coherent Soft X-Rays
Authors: Schaap B. H. , de Raadt T. C. H. , Nijhof D. F. J. , Franssen J. G. H. , Mutsears P. H. A. , Luiten O. J.
Published: January 2021

Electron bunches from a photoionized ultracold atomic gas enable the generation of spatially coherent soft-X-ray pulses trough inverse Compton scattering. Combined with at source prebunching, a compact, fully coherent soft X-ray source is proposed.
Table-top XUV Beamline for Coherent Diffractive Imaging of Isolated Gas-phase Nanoparticles
Authors: Senfftleben Björn , Kretschmar Martin , Hoffmann Andreas , Sauppe Mario , Tümmler Johannes , Will Ingo , Nagy Tamás , Vrakking Marc J.J. , Rupp Daniela , Schütte Bernd
Published: January 2021

An XUV beamline based on high-harmonic generation (HHG) is presented. Recent observation of Ar5+ in XUV ionization experiments indicates high potential for XUV nonlinear optics and coherent diffractive imaging (CDI) with sub-femtosecond resolution.
Ptychographic Phase-Sensitive Imaging Reflectometry for Depth-Resolved Nanostructure Characterization using Tabletop EUV Light
Authors: Jenkins Nicholas W. , Tanksalvala Michael , Esashi Yuka , Porter Christina L. , Wang Bin , Horiguchi Naoto , Jacobs Matthew N. , Gerrity Michael , Kapteyn Henry C. , Murnane Margaret M.
Published: January 2021

We present a versatile, ptychographic phase-sensitive imaging EUV reflectometer that can nondestructively image samples with spatial, depth and compositional resolution, with sensitivities to dopant levels and interface quality.
4.19 μm Fe2+ Ions Lasing in Zn1-xMnxSe:Cr2+,Fe2+ (x = 0.05) Single Crystal under 1.71 μm Laser Diode Pumping via Cr2+ → Fe2+ Ions Energy Transfer
Authors: Říha Adam , Doroshenko Maxim E. , Jelínková Helena , Němec Michal , Vyhlídal David , Jelínek Michal , Šulc Jan , Papashvili Alexander G. , Kovalenko Nazar O. , Terzin Igor S.
Published: January 2021

Laser-diode (~1.71 μm) pumped Zn1-xMnxSe:Cr2+,Fe2+ (x = 0.05) crystal through Cr2+→Fe2+ energy-transfer resulting in ~4.19 μm lasing within temperature range of 78–110 K, maximum mean laser output power of 4.1 mW, and slope-efficiency of 2.3% is presented.
High-sensitivity Real-time Optical Pulse Detector for High‑power Fiber-based MOPA Laser Systems
Authors: Grzes Pawel , Michalska Maria , Swiderski Jacek
Published: January 2021

A novel high-sensitivity real-time laser pulse detector is presented. It is designed to monitor energetic properties of optical signals in critical points of a MOPA laser system. Possible applications of the system are also discussed.
Tomographic Reconstruction Algorithms for Laser Wakefield Acceleration Gas Targets
Authors: Lorenz S. , Grittani G. , Goncalves L. V. N. , Lazzarini C. M. , Limpouch J. , Nevrkla M. , Bulanov S. , Korn G.
Published: January 2021

In this work we focus on the reconstruction of the density profiles from tomographic measurements. We compare different analytical and iterative methods, and we propose a new one tailored for the reconstruction of gas targets.
Nanosecond Pulse Enhancement in Narrow Linewidth Cavity for Steady‐State Microbunching
Authors: Zhou Qinghong , Tu Lisha , Chen Liuying , Liu Jun , Ying Ma‐Ke , Lei Karen , Luo Hao-Wen , Wu Juhao , Chao Alexander W.
Published: January 2021

In a Steady-State Microbunching light source, a 100 nanosecond long pulse is enhanced in a cavity to megawatts average power. A novel enhancement scheme is invented. Modeling and simulation are conducted to demonstrate its feasibility.
Analysis of flux densification methods in a lighting system based on AOTF
Authors: Beliaeva A.S. , Romanova G.E.
Published: January 2021

One of the problems of systems based on the acoustic-optical cells is the low efficiency of using light flux of broadband sources. We consider different ways to increase the efficiency in such type of schemes
Gauge-Invariant Time-Dependent Configuration Interaction Singles Method for High-Order Harmonic Generation in Molecules
Authors: Teramura Takuma , Sato Takeshi , Ishikawa Kenichi L.
Published: January 2021

We present a numerical implementation of the gauge-invariant time-dependent configuration interaction singles method for high-order harmonic generation in molecules. We demonstrate successful simulations for propane of low symmetry.
Femtosecond laser-induced plasma evolution studies via third-harmonic enhancement in atomic and molecular gases
Authors: Jusko Christoph , Sridhar Abhishek , Appi Elisa , Shi Liping , Morgner Uwe , Kovacev Milutin
Published: January 2021

We present studies about the temporal evolution of femtosecond laser-induced plasma in atomic and molecular gases. The evolution is imprinted in the enhanced third-harmonic signal from a filament intersected by the plasma under investigation.
Time Domain Spectroscopy of Methane Excited by Resonant High-Energy Mid-IR Pulses
Authors: Crippa G. , Faccialà D. , Geetha P. Prasannan , Pusala A. , Bonanomi M. , Cinquanta E. , Ciriolo A. G. , Devetta M. , Gatto L. , Stagira S. , Vozzi C.
Published: January 2021

We report on the efficient excitation of high-lying rovibrational states in methane by a high-energy mid-IR source and on the time-domain study of the induced dynamics.
XUV Reflection and Ellipsometry Experiments at ELIBeamlines
Authors: Espinoza Shirly , Samparisi Fabio , Zahradník Martin , Albrecht Martin , Finke Ondřej , Antipenkov Roman , Hort Ondřej , Rebarz Mateusz , Jurkovič Matej , Poletto Luca , Nejdl Jaroslav , Andreasson Jakob
Published: January 2021

We report on the results of the recent experiments of the XUV ELIps reflection and ellipsometry station at ELI Beamlines. Using the High Harmonic Generation source and a 1 kHz in-house developed laser, experiments in known samples such as GaN, STO and SiC were done and will be discussed.
Er:YAG microchip for lasing in spectral range 2.94 µm and gain switching generation
Authors: Švejkar Richard , Šulc Jan , Jelínková Helena
Published: January 2021

Highly doped Er:YAG microchip was prepared to make laser resonator compact and generate short pulses in gain switching regime. Pulse duration 306 ns with peak power 7 W and repetition rate 400 Hz were reached.
Temperature-Dependent Terahertz Time-Domain Spectroscopy of Mg-doped Stoichiometric Lithium Niobate
Authors: Buzády Andrea , Gálos Réka , Makkai Géza , Wu Xiaojun , Tóth György , Kovács László , Almási Gábor , Hebling János , Pálfalvi László
Published: January 2021

The absorption coefficient and refractive index spectra of 0.7 mol% Mg-doped stoichiometric lithium niobate were determined in the terahertz frequencies. The phase-matching parameters extracted from time-domain measurements were given in a wide temperature range.
Comparative study of terahertz pulse generation from one- and two-color laser pulses in the mid-infrared spectral range
Authors: Flender Roland , Borzsonyi Adam , Kiss Balint , Chikan Viktor
Published: January 2021

Terahertz pulse generation from one- and two-color laser pulses in the mid-infrared spectral range are investigated numerically. The results show, that the one-color (two-color) method is more effective under (over) 1.5 optical cycles.
High Sensitivity Characterization of LWFA Gas Jet Targets
Authors: Raclavský M. , Karatodorov S. , Chaulagain U. , Lamač M. , Nejdl J.
Published: January 2021

We report on a double-pass Michelson interferometer setup with increased sensitivity for characterization of the spatial density distribution of gas jets used as targets for LWFA experiments at ELI Beamlines facility.
Generation of Continuously-Tunable, Narrowband THz Pulses from Phase-Locked Femtosecond Pulse Bursts
Authors: Krizsán Gergő , Stummer Vinzenz , Flöry Tobias , Kaksis Edgar , Pugžlys Audrius , Baltuška Andrius , Polónyi Gyula , Fülöp József A.
Published: January 2021

We demonstrate generation of continuously-tunable, narrowband THz pulses from phase-locked multi-millijoule femtosecond pulse bursts by optical rectification in a tilted-pulse-front setup. Experimental results indicate advances in both, femtosecond pulse burst and high-energy THz source technology.
Few-cycle OPCPA at 2 µm with up to 100 W average power
Authors: Buss Jan Heye , Starosielec Sebastian , Grguras Ivanka , Golz Torsten , Prandolini Mark , Schulz Michael , Kraus Peter , Riedel Robert
Published: January 2021

A high-power optical parametric chirped-pulse amplifier (OPCPA) at 2 µm wavelength, pumped by kW-class Yb:YAG InnoSlab with an average power scalability up to 100 W and pulse durations in the few-cycle regime is presented.
Waveform Reproducibility from an OPA-based Parallel Synthesizer
Authors: Silva-Toledo Miguel A. , Rossi Giulio Maria , Mainz Roland E. , Yang Yudong , Scheiba Fabian , Keathley Phillip D. , Cirmi Giovanni , Kärtner Franz X.
Published: January 2021

The long-term stability of an optical parametric amplification-based waveform synthesizer is evaluated via the sequential acquisition of attosecond streaking spectrograms. We observe stable extreme ultraviolet high-harmonic continua and waveform reproducibility for more than 2 hours.
Effects of Autoionizing States in High Harmonic Generation and Attosecond Pulse Production
Authors: Strelkov V.V. , Khokhlova M.A.
Published: January 2021

Strong-field approximation is generalized to describe HHG enhanced by a resonance with autoionizing state. Resonantly induced dephasing compensates the attochirp allowing attosecond-pulse shortening in conjunction with resonance-induced intensity increase by order of magnitude or more.
Extraction of higher-order nonlinear electronic response in solids using high harmonic generation
Authors: Ortmann Lisa , Han Seunghwoi , Kim Hyunwoong , Kim Yong Woo , Oka Takashi , Chacon Alexis , Doran Brent , Ciappina Marcelo , Lewenstein Maciej , Kim Seung-Woo , Kim Seungchul , Landsman Alexandra S.
Published: January 2021

We extract the high-order nonlinear electronic response of sapphire to a laser pulse using high-harmonic light emitted from the material, obtaining susceptibilities of the same order as the measured high harmonics (7th, 9th and 11th).
High-order Nonlinear Dipole Response Characterized by Extreme-Ultraviolet Ellipsometry
Authors: Chang Kuang-Yu , Huang Long-Cheng , Asaga Koji , Tsai Ming-Shian , Rego Laura , Huang Pei-Chi , Mashiko Hiroki , Oguri Katsuya , Hernández-García Carlos , Chen Ming-Chang
Published: January 2021

We demonstrate that polarization control and characterization of high-harmonic generation in non-collinear geometry perform as excellent ellipsometry that can precisely retrieve the non-perturbative dipole response, both amplitude and phase, in the extremely nonlinear up-conversion process.
Buildup of Post-Recombination Refractive Index Changes in Krypton Photoionized at High Repetition Rates
Authors: Koehler J. R. , Köttig F. , Schade D. , Tani F. , Russell P. St. J.
Published: January 2021

The evolution of a recombination-driven density depression in a krypton-gas-filled capillary, photoionized at MHz repetition rates, is interferometrically tracked. The msec-long buildup increases in amplitude with pulse energy and repetition rate.
Electron acceleration with high-intensity radially-polarized laser beams having spatio-temporal couplings
Authors: Jolly Spencer W.
Published: January 2021

Low-order spatio-temporal couplings have a significant effect on free-space acceleration of electrons via intense radially-polarized laser beams. We show the effects of longitudinal chromatism and a spectrally-varying spatial beam width.
Rotational Quantum Beat Lasing without Inversion
Authors: Richter Maria , Lytova Marianna , Morales Felipe , Haessler Stefan , Smirnova Olga , Spanner Michael , Ivanov Misha
Published: January 2021

We show that lasing without inversion arises naturally during propagation of intense femtosecond laser pulses in air. It is triggered by the combination of molecular ionization and molecular alignment, both unavoidable in intense light fields.
Towards a 100 TW, sub-5-fs Optical Parametric Synthesizer
Authors: Fischer P. , Nagy G. , Muschet A. , De Andres A. , Salh R. , Veisz L.
Published: January 2021

We report on details of a peak-power upgrade of a sub-5-fs Optical Parametric Synthesizer towards 100 TW. System design, pump pulse delaying and relay imaging system are presented. A tailored second and third harmonic generation reaches conversion efficiencies of 80% and 60% with 80ps pump pulses.
A Novel Attosecond Timing Tool for Free-Electron Laser Experiment
Authors: Maroju Praveen K. , Moioli Matteo , Ertel Dominik , Ahmadi Hamed , Sansone Giuseppe , Grazioli Cesare , Di Fraia Michele , Plekan Oksana , Finetti Paola , Allaria Enrico , Giannessi Luca , Spezzani Carlo , Penco Giuseppe , Spampinati Simone , Demidovich Alexander , Danailov Miltcho , Borghes Roberto , Kourousias Georgios , Reis Carlos Eduardo Sanches Dos , Billé Fulvio , Prince Kevin C. , Callegari Carlo , De Ninno Giovanni , Lutman A. , Squibb Richard J. , Feifel Raimund , Carpeggiani Paolo , Mazza Tommaso , Meyer Michael , Bengtsson Samuel , Ibrakovic Neven , Simpson Emma Rose , Mauritsson Johan , Csizmadia Tamás , Dumergue Mathieu , Kühn Sergei , Harshitha N.G. , You Daehyun , Ueda Kiyoshi , Labeye Marie , Bækhøj Jens Egebjerg , Schafer Kenneth J. , Gryzlova Elena V. , Grum-Grzhimailo Alexei N.
Published: January 2021

We demonstrate a novel timing tool for Free-Electron Lasers to determine the delay between an attosecond pulse train and infrared pulse with sub-optical-cycle resolu-. tion.
Synchronized HHG based source at FLASH
Authors: Appi Elisa , Papadopoulou Christina C. , Mapa Jose , Wesavkar Nishad , Jusko Christoph , Mosel Philip , Alisauskas Skirmantas , Lang Tino , Heyl Christoph M. , Manschwetus Bastian , Braune Markus , Brachmanski Maciej , Lindenblatt Hannes , Trost Florian , Meister Severin , Schoch Patrizia , Treusch Rolf , Moshammer Robert , Hartl Ingmar , Morgner Uwe , Kovacev Milutin
Published: January 2021

We present a VUV beamline installed as pump-probe source at the free-electron laser FLASH. The source is based on high-order harmonic generation driven by femtosec-ond near-infrared laser pulses synchronized with the FEL burst mode.
Photoionization and Photodissociation studies using a combination of a novel high-repetition rate HHG source and a REMI
Authors: Harth Anne , Shobeiry Farshad , Srinivas Hemkumar , Bharti Divya , Pfeifer Thomas , Moshammer Robert
Published: January 2021

We present a novel high-repetition rate (143 kHz) attosecond beamline in combination with a reaction microscope in order to study time, 3D-momentum and channel resolved photoionization and dissociation processes. We present channel resolved RABBITT measurements.
Recent Progress on the Shanghai Superintense Ultrafast Laser Facility (SULF) at SIOM
Authors: Liang Xiaoyan , Leng Yuxin , Li Ruxin , Xu Zhizhan
Published: January 2021

SULF laser based on chirped pulse amplification (CPA) was built in Shanghai. The amplified energy of 422 J was achieved at repetition rate of one shot per 3 minutes. After compressor, the pulse duration was measured to be 23.4 fs with a throughput efficiency of 71.3%, which correspond to a peak power of 12.9PW.
Single-Cycle Pulse Compression at 10 MHz Repetition Rate in Gas-Filled Hollow-Core Photonic Crystal Fiber
Authors: Schade D. , Köttig F. , Koehler J. R. , Frosz M. H. , Tani F. , Russell P. St.J.
Published: January 2021

Fiber laser pulses at 1030 nm are compressed from ~340 fs to 3.8 fs at repetition rates up to 10 MHz in a two-stage setup using gas-filled single-ring photonic crystal fibers with >70% total transmission.
High-energy sub-5 fs pulses from a Ti:sapphire laser
Authors: Nagy Tamás , Kretschmar Martin , Rouzée Arnaud
Published: January 2021

6.3mJ, sub-5fs pulses are generated at 1kHz by compressing high-energy Ti:Sapphire laser pulses in a 3.75m long stretched capillary.
Laser-plasma proton acceleration from under-critical density targets in a gas-mixture.
Authors: Levato T. , Giuffrida L. , Kantarelou V. , Nevrkla M. , Bonora S. , Baffigi F. , Brandi F. , Fulgentini L. , Koester P. , Labate L. , Palla D. , Gizzi L. A. , Margarone D.
Published: January 2021

High-repetition rate target development for proton acceleration by laser-plasma experiments is of great importance for future multidisciplinary applications, as envisioned at the ELIMAIA user beamline. The use of gas-jet based target, capable of high-repetition rate (10Hz and beyond) and typically used to generate under-critical density plasma, can overcome such problematic using a gas-mixture. We report on acceleration of protons from an under-critical plasma in a gas-jet-mixture capable of high-rep.-rate using a 4.3-J, 27-fs laser beam system. The interaction has been optimized using a deformable mirror prototype as envisioned in the ELIMAIA beamline to improve the flexibility in user experiments.
Progress towards a LWFA-based X-ray machine for plant phase-contrast X-ray imaging
Authors: Fourmaux S. , Lassonde P. , Payeur S. , Chaulagain U. , Mironov S. , Ginzburg V. , Khazanov E. , Hallin E. , Mourou G. , Kieffer J.C.
Published: January 2021

We present a review of INRS program on intense X-ray sources based on laser wake-field acceleration for high throughput plant imaging. Key technical points to achieve the best compromise between complexity and performance are discussed.
Defect detection based on sensor data fusion of optical monitoring systems in laser based Powder Bed Fusion
Authors: Merschroth Holger , Harbig Jana , Weigold Matthias
Published: January 2021

Due to time and cost-intensive quality assurance of LPBF an in-process monitoring is developed by data fusion of photodiodes, thermography and high–speed camera on three abstraction levels resulting in a defect detection of 86 %.
Picosecond laser microwelding of ultra-thin flexible glass
Authors: Hand Duncan P. , Morawska Paulina O. , Carter Richard M. , Daniel Esser M. J. , Chan Yun F. , Melgari Paolo , Douglas Robert
Published: January 2021

Ultra-thin flexible glass is of significant interest for photonics packaging, combining the hermeticity typically required (e.g. for OLED technologies) with high flexibility. We demonstrate picosecond laser welding for bonding flexible glass and creating hermetic packages.
Ultrafast-Laser-Enabled Microwelding and Waveguide Inscription for Optics and Laser Fabrication
Authors: Qiao J. , Feng T. , Sahoo P. K. , Patra S. , Haque R. , Dorrer C.
Published: January 2021

A dynamic pulse propagation modeling for femtosecond laser bonding of transparent materials is developed, accurately predicting temperature evolution and internal modifications. Waveguide lasers inscribed by a femtosecond laser are demonstrated.
Advanced Capabilities in Laser Surface Polishing and Functionalization at the National Research Council of Canada
Authors: Bordatchev Evgueni V.
Published: January 2021

Present report introduces some of most valuable achievements and developments of laser surface polishing and laser surface functionalization F technologies at the National Research Council of Canada over the past five years.
High-speed high-resolution multi-beam micromachining with ultrashort pulsed lasers
Authors: Hauschwitz Petr
Published: January 2021

Advances in a development of high-power ultrashort laser systems enable rapid large-scale micromachining such as multi-beam simultaneous cutting and drilling with 784 beams, large-scale interference patterning of metals, glass and composite materials.
High Resolution Mid-Infrared Range Determination through Photon Counting
Authors: Widarsson Max , Henriksson Markus , Mutter Patrick , Canalias Carlota , Pasiskevicius Valdas , Laurell Fredrik
Published: January 2021

Up-conversion of 2.4 µm pulses to 737 µm was performed which allowed for range determination measurements with conventional Si-based detectors. Temporal resolution of 42 ps was achieved, allowing distinguishability between targets separated by few millimeters.
kW class nanosecond polarization-maintaining Holmium MOPA at 2050 nm and 2090 nm
Authors: Romano Clément , Lorenz Dominik , Eichhorn Marc , Kieleck Christelle
Published: January 2021

We report on a polarized MOPA operating at 2050 nm or 2090 nm delivering pulses in the nanosecond regime from 10 kHz to 1 MHz. Peak powers greater than 1 kW are demonstrated.
Sub-two-cycle pulses in the mid-IR based on thin plate compression at high average power
Authors: Kurucz Máté , Flender Roland , Haizer Ludovít , Nagymihály Roland S. , Cormier Eric , Kiss Bálint
Published: January 2021

Spectral broadening of 3.2 µm pulses is experimentally demonstrated at 8.2 W average power output through nonlinear propagation in thin crystal plates. Sub-two-cycle compression was achieved with a bulk compressor and custom-made dispersive mirrors.
Ultra-stable OPCPA at 2 μm, 16 fs, sub 100 mrad CEP noise
Authors: Maksimenka R. , Jargot G. , Thiré N. , Pertot Y. , Forget N.
Published: January 2021

We demonstrate an OPCPA system delivering 35µJ, 2.5 cycles pulses (15.9fs), centered at 2µm pumped by a 500µJ, sub-ps Yb:YAG laser. Non-averaged CEP noise of 94mrad is achieved.
High-power mid-infrared OP-GaAs OPO with controllable pulse repetition-rates and durations
Authors: Fu Q. , Xu L. , Liang S. , Shardlow P. C. , Shepherd D. P. , Alam S.-U. , Richardson D. J.
Published: January 2021

We report a high-power, mid-infrared OP-GaAs OPO with controllable pulse repetition rates (100 MHz – 1 GHz) and adjustable pulse durations (~95 ps – ~1.1 ns). The highest average output power of 13.7 W was achieved from the OPO with 9.2 W signal (3.3 μm) and 4.5 W idler (4.9 μm).
Development of new generation lithium niobate-based high energy single-cycle terahertz sources
Authors: Pálfalvi László , Tibai Zoltán , Almási Gábor , Mischl-Ruzsik Barbara , Hebling János , Tóth György
Published: January 2021

Three new-generation terahertz sources are presented. These setups can solve the problems of energy-scalability and pulse-homogeneity. More than 15-mJ THz energy is predicted, nearly two orders of magnitudes higher than has been achieved earlier.
Enhancing the Efficacy of Collinear Optical Rectification for Broadband THz Radiation at MHz Repetition Rates
Authors: Buchmann Tobias Olaf , Kelleher Edmund John Railton , Zhou Binbin , Jazbinsek Mojca , Kwon O-Pil , Seok Jin-Hong , Rotermund Fabian , Jepsen Peter Uhd
Published: January 2021

We demonstrate an optical-to-THz energy conversion efficiency of 5.5 ⋅ 10−4, by pumping the organic crystal HMQ-TMS with the externally compressed output of a Yb:fibre laser, enabling several kV/cm field strengths at MHz repetition rates.
Mid-IR gas-filled Raman fiber laser at 4.22 μm with high pulse energy and efficiency
Authors: Wang Yazhou , Dasa Manoj K. , Adamu Abubakar I. , Antonio-Lopez J. E , Habib Selim , Amezcua-Correa Rodrigo , Bang Ole , Markos Christos
Published: January 2021

A mid-IR 4.22 µm Raman laser targeting CO2 absorption line is reported based on a hydrogen-filled hollow-core fiber. Quantum efficiency as high as 74% was achieved at 20 bar with 17.6 µJ pulse energy.
Rod and Slab Type Cw and Q-switched Tm:YLF Lasers
Authors: Kucirek Philipp , Erben Benjamin , Hörmann Florian , Traub Martin , Hoefer Marco
Published: January 2021

We report on Tm:YLF Lasers with optical efficiencies close to 40%, output-power and pulse-energy of 25 W and 2 mJ @ 9 kHz for the rod and an output power of 256 W for the slab type Laser.
Holmium-doped fibers for efficient fiber lasers at 2100 nm
Authors: Kamrádek Michal , Aubrecht Jan , Jelínek Michal , Frank Milan , Peterka Pavel , Honzátko Pavel , Mrázek Jan , Vařák Petr , Podrazký Ondřej , Todorov Filip , Kubeček Václav , Kašík Ivan
Published: January 2021

Holmium-doped fibers with a low laser threshold and a slope efficiency exceeding 80% prepared by a nanoparticle-doping method are demonstrated. We proved the key factor for efficient holmium lasers is a ratio of Al/Ho greater than 60.
Barium Nonlinear Optical Crystals for the Mid-IR: Characterization and Applications
Authors: Petrov Valentin , Badikov Valeriy V. , Badikov Dmitrii V. , Shevyrdyaeva Galina S. , Kato Kiyoshi , Miyata Kentaro , Mitin Konstantin V. , Wang Li , Panyutin Vladimir
Published: January 2021

The linear and nonlinear optical properties of BaGa4S7 (BGS), BaGa4Se7 (BGSe), BaGa2GeS6 (BGGS), and BaGa2GeSе6 (BGGSe) are reviewed, highlighting their potential for frequency down conversion of powerful laser sources from the near- to the mid-IR.
Stamp method for QPM quartz fabrication
Authors: Ishizuki Hideki , Taira Takunori
Published: January 2021

Polarity inversion using a QPM stamp method is proposed for fabrication of QPM quartz device. Polarity inversion of x-cut quartz and demonstration of 532-nm generation with 16.8 kW peak intensity from a QPM quartz were realized for initial evaluation.
High-brightness THz Source with Wide Tunability
Authors: Murate Kosuke , Kawase Kodo
Published: January 2021

In this study, we demonstrated a terahertz (THz) spectroscopic imaging system using a multiwavelength injection-seeded THz parametric generator (is-TPG). Multiwavelength is-TPG can identify reagents based on the repetition rate of the pump laser because the spectroscopic measurement is performed in a single pulse. Furthermore, highly stabilized measurements are realized by splitting the high-brightness THz wave into measurement and reference beams. This system significantly shortens the measurement time for spectroscopic imaging with high stability.
XT-considered multiple backup paths and resources shared protection scheme based on ring covers
Authors: Yin Shan , Guo Shijia , Meng Xiangkai , Ma Rong , Guo Bingli , Huang Shanguo
Published: January 2021

With the rapid development of space division multiplexing (SDM) and flexible grid technology, the problem of resource allocation in optical network becomes much more complicated. Although there emerge a substantial number of works about link protection or restoration in SDM-EONs mesh networks, the topic of survivability is dug deeper in this work. It is acknowledged that protection schemes based on ring covers bring the advantages of shorter restoration time and lower costs. However, the RSCA problem in SDM-EON for link protection based on ring covers has rarely been investigated. To enhance the survivability of SDM-EON and make the best use of ring covers, we initially select a set of rings for the protection of all the links in a network topology according to constrains, aiming at taking full advantages of network resources. After that, we propose an algorithm to recover the traffic which will break off under link failures, basing on the set of rings. At the end of this protection scheme, we arrange the resources fulfilling the constrains of spectrum contiguity and core continuity constrains by using several different algorithms considering physical impairment. Based on the allocation in both spacial and spectral dimensions, our algorithms achieve better results of survivability. According to the simulations conducted for the evaluation of the proposed algorithms, our algorithms manage to recover at least 72.8% of traffic when the traffic request number is set to be 1000.
Improvement of LIBS signal stability for NaCl solution using femtosecond laser-induced water film
Authors: Zhang Dan , Chen Anmin , Wang Qiuyun , Zhang He , li Suyu , Jin Mingxing
Published: January 2021

This paper studies the analysis of Na element concentration in NaCl aqueous solution using laser-induced breakdown spectroscopy (LIBS). The NaCl solution is transformed to a thin water film. The water film can provide a stable liquid surface, and overcome the disadvantage that laser focusing position cannot be fixed due to liquid level fluctuation (when nanosecond laser is used as the excitation light source, there is serious liquid splash phenomenon, which affects the signal stability). And, femtosecond pulse laser is used to excite the water film to produce the plasma, avoiding liquid splashing. The measured emission lines are Na (I) at 589.0 nm and 589.6 nm. The calibration curves of sodium are plotted by measuring different concentrations of NaCl solution. The linear correlation coefficients of Na (I) lines at 589.0 nm and 589.6 nm are 0.9928 and 0.9914, respectively. In addition, the relative standard deviation is also calculated; its range is from 1.5% to 4.5%. The results indicate that the combination of femtosecond laser and water film can significantly improve the signal stability for liquid analysis in LIBS.
Surface topology and functionality of freeform microlens arrays
Authors: Aderneuer Tamara , Fernandez Oscar , Karpik Agnieszka , Werder Jerome , Marhöfer Maximilian , Magnus Kristiansen Per , Ferrini Rolando
Published: January 2021

Nonsymmetric (also known as freeform) optical components have attracted a great deal of academic and industrial attention due to the substantial benefits they have demonstrated in imaging and nonimaging optical systems. Additionally, freeform microlens arrays (FMLAs) are very promising with regard to the growing demand for device miniaturization and cost reduction. As a flip side, FMLAs entail specific challenges in design, manufacturing, and characterization. Here we report on the latter and present an innovative characterization strategy that makes it possible to assess the quality of FMLAs quickly and accurately. The precisely measured surface topology of FMLAs was accurately represented using nonuniform rational basis-spline (NURBS) and its optical response was predicted by means of ray-tracing simulations. We show that for reliably measured surface topology, the results are in excellent agreement with the experimental measurements. We also show that, compared to previous studies, illuminance levels displayed in a logarithmic scale are more adequate for low light levels and represent a closer match to nonlinear human visual perception. We believe that the method presented here will contribute to speeding up the FMLA manufacturing process, one of the current downsides of this promising technology.
Hybrid holographic Maxwellian near-eye display based on spherical wave and plane wave reconstruction for augmented reality display
Authors: Wang Zi , Zhang Xu , Lv Guoqiang , Feng Qibin , Ming Hai , Wang Anting
Published: January 2021

The holographic Maxwellian display is a promising technique for
augmented reality (AR) display because it solves the
vergence-accommodation conflict while presenting a high-resolution
display. However, conventional holographic Maxwellian display has the
inherent trade-off between depth of field (DOF) and image quality. In
this paper, two types of holographic Maxwellian displays, the
spherical wave type and the plane wave type, are proposed and
analyzed. The spherical wavefront and the plane wavefront are produced
by a spatial light modulator (SLM) for Maxwellian display. Due to the
focusing properties of different wavefronts, the two types of display
have complementary DOF ranges. A hybrid approach combining the
spherical wavefront and plane wavefront is proposed for a large DOF
with high image quality. An optical experiment with AR display is
demonstrated to verify the proposed method.
Robust point-process Granger causality analysis in presence of exogenous temporal modulations and trial-by-trial variability in spike trains
Authors: Casile Antonino , Faghih Rose T. , Brown Emery N.
Published: January 2021

Assessing directional influences between neurons is instrumental to understand how brain circuits process information. To this end, Granger causality, a technique originally developed for time-continuous signals, has been extended to discrete spike trains. A fundamental assumption of this technique is that the temporal evolution of neuronal responses must be due only to endogenous interactions between recorded units, including self-interactions. This assumption is however rarely met in neurophysiological studies, where the response of each neuron is modulated by other exogenous causes such as, for example, other unobserved units or slow adaptation processes. Here, we propose a novel point-process Granger causality technique that is robust with respect to the two most common exogenous modulations observed in real neuronal responses: within-trial temporal variations in spiking rate and between-trial variability in their magnitudes. This novel method works by explicitly including both types of modulations into the generalized linear model of the neuronal conditional intensity function (CIF). We then assess the causal influence of neuronionto neuronjby measuring the relative reduction of neuronj’s point process likelihood obtained considering or removing neuroni. CIF’s hyper-parameters are set on a per-neuron basis by minimizing Akaike’s information criterion. In synthetic data sets, generated by means of random processes or networks of integrate-and-fire units, the proposed method recovered with high accuracy, sensitivity and robustness the underlying ground-truth connectivity pattern. Application of presently available point-process Granger causality techniques produced instead a significant number of false positive connections. In real spiking responses recorded from neurons in the monkey pre-motor cortex (area F5), our method revealed many causal relationships between neurons as well as the temporal structure of their interactions. Given its robustness our method can be effectively applied to real neuronal data. Furthermore, its explicit estimate of the effects of unobserved causes on the recorded neuronal firing patterns can help decomposing their temporal variations into endogenous and exogenous components.