1999 Fiscal Year Final Research Report Summary
Coherent phonon generation by light pulse train and Optical control of material propeties
| Project/Area Number |
10440092
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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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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Osaka University |
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Principal Investigator |
KINASLUTAL Shuichi Graduate School of Science, Osaka University Professor, 大学院・理学研究科, 教授 (10112004)
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| Co-Investigator(Kenkyū-buntansha) |
木下 修一 大阪大学, 大学院・理学研究科, 教授 (10112004)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Femtosecont pulse / coherent phonon / four-wavemixing / Pulse shaping / Stimulated Raman scattering |
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| Research Abstract |
The frequency modes below 3 THz in materials are called "low frequency modes" in light scattering experiment and are known to relate directly with the material properties. In liquid, the low frequency phonon modes and the relaxational mode dominate over this region. The relaxational mode is peculiar to liquid state and is believed to play an important role in connecting the microscopic degrees of freedom with the macroscopic quantities.
In the present work, we have developed various methods to create multipulses; directly created by slightly detuned laser cavity and by employing the Fourier transform pulse shaping apparatus. Particularly we have divided an amplified pulse into two, which are applied independently by the amplitude modulations to create two-color synchronous pulses. Using these pulses, we have observed the diffraction from the moving grating in the four-wave mixing configuration. This method is particularly suitable for the selective excitation of the phonon modes without exciting the relaxational mode.
We further perform the frequency-domain four-wave mixing (FD4WM) spectroscopy by employing a Q-switched YLF laser synchronously oscillating as a probe. It is found that this spectroscopy efficiently offers the information on the frequency response excited by the pump pulses and becomes suitable to observe the phonon dynamics after selective excitation.
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Research Products
(15 results)
