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Study of hyper-Raman scattering excited by dye-laser for spectroscopic use in solids

固体光谱中染料激光激发的超拉曼散射研究

基本信息

批准号：
58460026
负责人：
INOUE Kuon
金额：
$ 5.5万
依托单位：
Shizuoka University Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1983
资助国家：
日本
起止时间：
1983 至 1984
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-58460026/
关键词：
hyper-Raman scattering laser-spectroscopy resonant light scattering dye-laser excitation phonon

项目摘要

1. For the first time, we have succeeded in observing the hyper-Raman signals of optic phonon in solids by using a repetitively pulsed dye laser. For this purpose, we have developed a high-sensitive detection-system.2. Thereby, we have for the first time studied experimentally the frequency dispersion of the hyper-Raman scattering efficiency in Tio_2 and SrTiO_3 crystals, in such a range that the relevant photon energies, i.e., twice the incident one, 2hwi and the scattered one, hws are across the fundamental absorption edge. As the result, it is found that the efficiency of the allowed phonon modes in the 90ﾟ scattering geometry increases remarkably, as 2hwi approaches the band gap Eg from below. This fact will enable one to perform more sensitive hyper-Raman experiments in the future.3.We have also shown that the above result can be reasonably interpreted in terms of a two-photon ongoing resonance with Eg.4. We have found that the forbidden longitudinal phonon normally forbidden in the backward scattering geometry in a rutile crystal shows a sharp and striking two-photon resonant behavior at the band gap. The origin may be attributed to the resonance with the excitons due to the q-dependent- Fro^^"lich interaction. we have also observed a similar resonant behavior due to the LO phonon in SrTiO_3. we have interpreted this phenomenon as arising from the Fro^^"lich interaction.5. As a consequence, the resonant hyper-Raman spectroscopy in the above sense is a promising technique to unravel specific critical points of electronic band structure in solids, particularly in the ultraviolet region. It is noted that a photon energy of half the optical transition energy is sufficient.

1.首次利用重复脉冲染料激光器成功地观测到固体中光学声子的超拉曼信号。为此，我们研制了一种高灵敏度的检测系统。因此，我们首次实验研究了TiO_2和SrTiO_3晶体中超拉曼散射效率的频散，在这样的范围内，相应的光子能量，即入射光子能量的两倍，即入射光子能量的两倍，散射光子能量Hw，横跨了基频吸收边。结果发现，当2hwi从下向带隙靠近时，90ﾟ散射几何构型中允许声子模的效率显著增加。这一事实将使人们能够在未来进行更灵敏的超拉曼实验。3.我们还表明，上述结果可以用与Eg.4的双光子持续共振来合理解释。我们发现，金红石晶体中通常在后向散射几何中被禁止的纵向禁带声子在带隙处表现出尖锐而引人注目的双光子共振行为。这可能归因于与Q相关的LICH相互作用引起的激子共振。我们也观察到了由于SrTiO_3中的LO声子引起的类似的共振行为。我们解释这一现象是由FRO^^“LICH相互作用引起的。因此，上述意义上的共振超拉曼光谱是一种很有前途的技术，可以用来解开固体，特别是紫外区电子能带结构的特定临界点。要注意的是，光跃迁能量的一半的光子能量是足够的。