1998 Fiscal Year Final Research Report Summary
Effects of hot electron nonlinear transport in ultrafast photoretractive response
| Project/Area Number |
09650044
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | University of Electro-Communications |
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Principal Investigator |
TOMITA Yasuo University of Electro-Communications, Electro-Communications, Associate Professor, 電気通信理学部, 助教授 (50242342)
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| Project Period (FY) |
1997 – 1998
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| Keywords | photorefractive effect / nonlinear optical effect / space-charge field / picosecond pulses / semi-insulating semiconductors / hot electron |
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| Research Abstract |
The purpose of this study is to investigate ultrafast photorefractive (PR) responses in semiinsulating semiconductors. In particular, we focus on the effect of hot electron nonlinear transport on the dynamics of photoexcited space-charge fields. The main results of this study are listed below.
1. We carried out formulation and numerical calculation of the picosecond PR effect that includes the hot electron nonlinear transport in DC-biased semi-insulating GaAs. It was found that the magnitude of the space-charge field is increased by a factor of one owing to a large increase of the electron temperature. It was also found that the hot electron nonlinear transport gives rise to a collective teraherz oscillation of high electric field domains, leading to the same oscillatory behavior in the space-charge field's phase.
2. We clarified the effect of crystal-temperature on the picosecond PR effect, both theoretically and experimentally. Experimental results showed that although the transient energy transfer caused by photo-induced free carrier gratings had a week temperature dependence, such a dependence was not observed in the picosecond PR effect and two-photon absorption. This experimental finding was also supported by the theoretical analysis.
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