2000 Fiscal Year Final Research Report Summary
Development of high-speed and high-sensitivity semiconductor multiple quantum well photorefractive devices
| Project/Area Number |
11450025
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B).
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied optics/Quantum optical engineering
|
|---|
| Research Institution | University of Tokyo |
|---|
Principal Investigator |
KURODA Kazuo Institute of Industrial Science, University of Tokyo Professor, 生産技術研究所, 教授 (10107394)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MATOBA Osamu Institute of Industrial Science, University of Tokyo Associate Researcher, 生産技術研究所, 助手 (20282593)
SHIMURA Tsutomu Institute of Industrial Science, University of Tokyo Associate Professor, 生産技術研究所, 助教授 (90196543)
ARAKAWA Yasuhiko Research Center for Advanced Science and Technology, University of Tokyo Professor, 先端科学技術研究センター, 教授 (30134638)
ASIHARA Satoshi Institute of Industrial Science, University of Tokyo Associate Researcher, 生産技術研究所, 助手 (10302621)
|
|---|
| Project Period (FY) |
1999 – 2000
|
| Keywords | InGaAs / GaAs MQW / photorefractive device / near infrared light / exciton resonance / Franz-Keldysh effect / Quantum confined effect / real-time hologram |
|---|
| Research Abstract |
Photorefractive materials dynamically change the refractive index by the illumination of nonuniform intensity pattern. They have lots of potential applications, such as, high-speed parallel signal processing devices for next generation information network systems, high-speed adaptive sensor for vibration detection, near-infrared optical devices for biomedical applications, etc. The target of this research was to develop high-speed and high-sensitivity photorefractive materials using InGaAs/GaAs semiconductor multiple quantum wells. (1) We measured the lifetime and diffusion coefficient of photocarriers using time-resolved four wave mixing. The carrier lifetime is about 100 ps in proton-implanted samples. (2) We fabricated the photorefractive devices in quantum confined Stark geometry. The devices consist of the MQW layers sandwiched by SiO2 insulating layers. The diffraction efficiency is improved by 20 times in comparison with the Franz-Keldysh devices. However, the spatial resolution became poor. (3) In order to improve the spatial resolution, we used the low-temperature grown GaAs layers for insulating layers instead of SiO2 layers. This new structure substantially improved the spatial resolution of the devices. (4) We fabricated the devices that work at 1064 nm, that is, the wavelength of Nd : YAG laser. To fit the exciton resonance to this wavelength, the fraction of indium is increased in InGaAs quantum well layers. However, this results in large lattice constant mismatch between InGaAs and GaAs layers. The MQW layers are successfully grown on the properly designed buffer layer which releases the strain in the MQW layers.
|
