| Project/Area Number |
05452112
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | NAGOYA UNIVERSITY |
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Principal Investigator |
SAWAKI Nobuhiko Nagoya Univ., School of Engg., Prof., 工学部, 教授 (70023330)
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| Co-Investigator(Kenkyū-buntansha) |
後藤 英雄 中部大学, 工学部, 助教授 (00195942)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1994: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Coupled Quantum Well / Resonance of Electronic States / Optical Nonlinearity / Wave Mixing / Photoluminescence / Optical Absorption / Exiton / Modulator / デルタドープ構造 / ホトルミネッセンス |
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| Research Abstract |
The purpose of the research is to clarify the optical nonlinearity in a strongly coupled triple quantum well structure, where the application of an external field changes the situation of resonance of the electronic states. Thus the exciton oscillator strength should be a strong function of the external field. Since the electrons and holes have different tunneling escape times, after the excitation of carriers in a well by a femtosecond laser pulse, electrons will escape to the other well faster than holes, resulting the build up of internal field across the wells. This induced field could affect the change of the oscillator strength of excitons. Since the induced field will increase by increasing the input optical power, we can expect strong optical nonlinearity which will be responsible in the femtosecond region.
A GaAs/AlGaAs triple quantum well structure was made by MBE on a semiinsulating GaAs. The optical spectra was investigated using femtosecond laser pulse. The transmission of the laser light through the sample was investigated at various wave lengths. The transmittance was found to be a strong function of the input intensity. Above a critical power, the transmittance is decreased as the increase of the input power. The nonlinear behavior is enhanced near the anti-crossing energy associated with the triple resonance, which is in good agreement with the theoretical prediction.
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