Research Projects Supported by MEXT Through Special Subsidies for Private Universities and Institutions: Special Funds for the Creation of Strategic Research Infrastructure

Research Center for Advanced Photon Technology

About

Established and the first project started at 1997
The second project started at 2002, the third project at 2006, and the fourth project at 2011
Director:Professor Yasutake Ohishi

Research Outline

We are aiming at developing new materials for future innovative photonics devices. Broadband lightwave generation and processing are two major research items in this research center. It is necessary to research device structures to fully bring out the specific features for the developed photonics materials. Material research incorporated with device structure research can lead to the revolution of lightwave technologies. By combining new photonics devices with MEMS technology and materials, we will also develop new biosensing technology and solar energy conversion technology including photocatalysis. Our research activities in our project will lead to not only the innovation of information communication technologies, but also green and life innovation including environmental technology, medical sensing and diagnostics, etc.

Members

[Optical Functional Materials Laboratory]
Professor Yasutake Ohishi
Associate Professor Takenobu Suzuki
Post-Doctoral Fellow Zhongchao Duan
Post-Doctoral Fellow Gao Weiqing
Post-Doctoral Fellow Edmund P. Samuel
Post-Doctoral Fellow Tonglei Cheng
Post-Doctoral Fellow Dinghuan Deng
Technical Consultant Takayuki Iizuka
Secretary Etsuko Miyase

[Frontier Materials Laboratory]
Professor Kazuya Saito
Research assistant Edison Haruhiko Sekiya

[Micro-Nano Mechatronics Laboratory]
Professor Minoru Sasaki
Associate Professor Shinya Kumagai

[Quantum Interface Laboratory]
Associate Professor Akira Yamakata

Research Themes

Broadband lightwave processing
Broadband lightwave generation
Novel solar energy conversion technology

Background and Objective

 

 

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Miscellaneous

  • Development of high nonlinear microstructured optical fibers

We have developed novel high nonlinear microdtructured optical fibers (MOFs) to control chromatic dispersion control with high nonlinearity. They are appliedto supercontinuum generation and optical signal processing.
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  • Ultrabroadband supercontinuum(SC) generation
SC spectra by filamentation of tellurite and fluoride glass were measured.  They were pumped at 1600 nm by a pulse train with a pulse duration of 180 fsec and a repetition rate of 1 kHz.  The SC in tellurite covered a spectral range from 0.6 to 6 μm when the peak pulse power was 1.11 GW.  The SC in fluoride glass covered from 0.2 to 8 μm, when the peak pulse power was 1.13 GW.  The SC in fluoride glass spans more than 5 octaves.   The measured CE of SC in fluoride glass was 67%.  And the 3 dB bandwidth covered 1.15-4.76 μm.  The 20 dB bandwidth covered 0.39-7.4 μm.  To the best of our knowledge, both 3 dB and 20 dB bandwidths are the new records, and are much larger than all of the other reported data including silica fibers.  These properties of SCs show the potential of tellurite and fluoride glass as broadband SC generation media.
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Supercontinuum spectra by filamentation of (a) tellurite and (b) fluoride.

  • Development of solar-pumped glass gain media and solar-pumped fiber lasers
     

A solar-pumped laser is an optical device that converts sunlight into laser light beam. Laser efficiency, cooling systems, and beam quality of the solar-pumped laser still remain challenging issues.  These issues can be resolved by using fiber laser technique. So far, we have developed an optimum glass laser medium for solar pumping, clarified the possibility of solar-pumped fiber lasers by numerical simulation of double-clad fiber lasers, and achieved the world first single mode oscillation of fiber lasers by solar pumping.  We are investigating to achieve high efficiency and high power solar-pumped fiber lasers.
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 Solar-pumped fiber laser spectra.

 

  • Hetero-Integration of MEMS Micro-Fluidic Devices and Optical Fibers

The hetero-integration of the micro-fluidic device and the optical fiber generating super-continuum light is proposed for measuring the spectrum information including the infra-red absorption of the sample. Since the micro-fluidic device and the optical fiber are different in their production methods, the assembly becomes essential. A new bias spring with the reverse taper is proposed and realized with the control of Si etching profile. The transmission ratio of the light becomes double and the spectrum of water is measured as the demonstration. This device becomes the platform of variety of measurements.
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(a)Fabricated Si device showing the cross-section between the micro-channel (lateral) and the guide for the optical fiber (vertical). (b)Optical fiber set in the guide. (c)Magnified image between the fiber side and the bias spring with the reverse taper.


  • Development of photocatalysts using laser spectroscopy

Photocatalysts have attracted considerable attention due to their potential applications for water-splitting and degradation of pollutants by using solar energy. The efficiencies of photocatalysts are determined by the competition between recombination of charge carriers and the charge transfer to the reactant molecules. Therefore, understanding of the behavior of photogenerated charge carriers are indispensable to improve the efficiency of photocatalysts. We are studying the behavior of photogenerated charge carriers by using laser spectroscopy, and trying to develop highly efficient photocatalysts based on the obtained knowledge. 
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