| Project/Area Number |
18H01469
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 21050:Electric and electronic materials-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
挾間 優治 東京大学, 物性研究所, 助教 (80759150)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2020: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2019: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2018: ¥7,410,000 (Direct Cost: ¥5,700,000、Indirect Cost: ¥1,710,000)
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| Keywords | 半導体レーザー / 利得スイッチ / 超放射 / 光物性 / 非線形性 / 超放射、光物性 / 半導体物性 |
|---|
| Outline of Final Research Achievements |
In order to quantitatively evaluate emerging quantum mechanical coherence in the electronic system, and to characterize crossover from gain switching to superradiance, the phase relaxation time was measured in the presence of high-density electron-hole carriers forming population inversion. When the carrier density was gradually increased from weak to intense excitation conditions, the phase relaxation time decreased from several ps to below our time resolution, but then increased to 0.34 ps when population inversion region was formed. Theoretical calculations were made at the level of the second-order perturbation in the semiconductor Bloch equations, which explained the experimental results consistently.
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| Academic Significance and Societal Importance of the Research Achievements |
半導体レーザーからの利得スイッチ型の短パルス発生において、超放射の寄与が発生する可能性について肯定的な結論が得られた。利得スイッチから超放射のクロスオーバーに至るレベルまで半導体レーザーからの高速パルスを単発直接発生できれば、パルス繰り返しや発生タイミングの自在制御が可能な小型堅牢光源として、レーザー加工や生命科学・医療分野などへの広い応用が拓ける。
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