Form 1

2017 Report Form for Collaboration with
Research Center for Biomedical Engineering

Year/month/date

2018/3/20
2067

Numberdate:

Date /Month/Year
2018/3/20

To Chairman, Board of Directors, Research Center for Biomedical Engineering

Affiliation

Applicant Prof. Oliver B. Wright
Division of Applied Physics, Faculty of Engineering,
Hokkaido University

Title
Professor
Name Oliver B. Wright
Address
Division of Applied Physics, Faculty of Engineering, Hokkaido University 060-8628 Japan
Phone 011-706-7191
Fax
011-708-5192
E-mail olly@eng.hokudai.ac.jp
Report Form for Collaboration Research

Research Theme

Research Area

Research Period

Optical modulation with a plasmonic nanolens
1. Biomaterials
2. Bioengineering
3. Functional molecules④ Chemistry/Electrical Engineering/Mechanical Engineering/Materials Science

From:Date/month/Year
2018/7/1

To: Date/month/Year
2018/3/31

Applicant Organization
Name
Oliver B. WrightHidenori Mimura
Yuta Imade

Collaboration Partners
Research Center

Department
Faculty of Engineering, Hokkaido University
Research Institute of Electronics, Shizuoka
University
Faculty of Engineering, Hokkaido University

intheProf. Hidenori Mimura

Title
Prof.
Prof.
MrRoleTheory, analysis
Theory, analysis
Experiment,
theory, analysis

Research Results (Including Purpose, Results, Figures, etc.)
This project is aimed at the design of plasmonic nanolenses appropriate for GHz modulation. This study involvesa microlens that adjusts the refractive index gradient acoustically at GHz frequencies. It operates with GHz
surface acoustic waves or bulk waves excited by femtosecond laser pulses, in a circular-symmetric environment.
The first step of this research involved designing and simulating the device using commercial finite-element
analysis software (COMSOL). The present research stage involved fabrication and characterization. Figure 1
shows an optical micrograph of the sample, fabricated with the help of Prof. S. Juodkasis of Swinburne
University, Melbourne, representing by a gold Fresnel-zone-plate pattern of concentric rings, 100 nm thick, on aglass substrate. This lens was designed to have a focal length of 0.1 mm.

Fig. 1: Electron micrograph of the fabricated nanolens.
Each lens is about 100 microns in diameter.

Fig. 2: Reflectance image of a nanolens obtained bypoint by point scanning of an 830 nm focused
beam of 200 fs infrared optical pulses.

We have begun characterization of this lens using ultrafast optical point by point probing. So far we made areflectance image of this lens, as shown in Fig. 2.

List of Publications Related to the Collaboration Research'Gigahertz optomechanical modulation by split-ring-resonator nanophotonic meta-atom arrays'
Y. Imade, R. Ulbricht, M. Tomoda, O. Matsuda, G. Seniutinas, S. Juodkazis and O. B. WrightNano Letters 11, 6684 (2017)'Active chiral control of GHz acoustic whispering-gallery modes'
S. Mezil, K. Fujita, P. H. Otsuka, M. Tomoda, M. Clark, O. B. Wright and O. Matsuda
Appl. Phys. Lett. 111, 144103 (2017)'Ultrafast optical modulation by gigahertz acoustic perturbation of extraordinary optical transmission'
R. Ulbricht, H. Sakuma, Y. Imade, P. H. Otsuka, M. Tomoda, O. Matsuda, H. Kim, G. Park and O. B. WrightAppl. Phys. Lett. 110, 091910 (2017)'Upholding the diffraction limit in the focusing of light and sound'
A. A. Maznev and O. B. Wright
Wave Motion 68, 182-189 (2017)

List of Presentations ( Conference, Meeting, etc)

O. B. Wright, GHz Ultrasonics in Metamaterials, 2017 ICU Honolulu, Dec. 18-25 USA
List of Awards

Research plan for the next year (from April 1, 2018 to March 31, 2019), if the collaboration research is continued.
Prior consent from the collaboration partner in the Research Center is necessary.
This research concerns a project we started two years ago to develop an ultrafast optical modulation system basedon a plasmonic or Fresnel lens with sub-micron features that can be modulated with GHz surface acoustic waves.
After extensive optical simulations using COMSOL commercial software, we have designed and fabricated anappropriate Fresnel lens with a 1 mm focal length that is ideal for fabrication and evaluation. We propose to test
its optical characteristics with the help of Shizuoka University, and then proceed with GHz acoustic modulation
experiments at Hokkaido University. The goal is to demonstrate a significant modulation of light by means of a
nanoaperture placed in the focal plane of the lens when the lens is excited by a train of optical pump pulses andmodulated by GHz ultrasonic surface or bulk waves.

We expect to achieve the following:1) Spectral characterization of the nanolens focal length and transmission using equipment based in
Shizuoka University.
2) Characterization of the GHz modulation properties of the nanolens when combined with a nanoapertureusing a femtosecond-laser system at Hokkaido University. In particular, we shall implement temporal
Fourier transforms to understand the dependence of the optical modulation on ultrasonic frequency andpinpoint the optimal GHz frequency for optical modulation.