Brillouin Scattering Study on Thermal Phonon Resonance

热声子共振的布里渊散射研究

• 批准号: 07455043
• 负责人: TAKAGI Kenshiro
• 金额: $ 4.99万
• 依托单位: UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455043/
• 关键词: Phonon; Brillouin Scattering; Thermal Phonon Resonance; Sound Relaxation Phenomena; Non-Equilibrium State; Parallel Cavity; Cylindrical Cavity; 熱フォノン; フォノン共鳴; 光ビ-ト分光法

In our previous studies, we had already succeeded in introducing the optical beating spectroscopy technique to Brillouin scattering experiment. The resolution 100 to 1000 times higher than the previous experiments was realized The technique provided us with a very effective means to investigate various phenomena of molecular dynamics in soft materials including (a) the first observation of the true shape of Brillouin triplet, (b) anomalous spectrum shape of depolarized light scattering in highly anisotropic moleculeds, and (c) the observation of asymmetry between the Stokes and the anti-Stokes components of Brillouin peaks in materials out of equilibrium.The purpose of the present study was to apply the new technique for the thermal-phonon resonance, the strange phenomenon that the natural phonons confined in a limited space reveal resonance effect. We intended to describe the physical mechanism of the phenomenon and find its applications, for instance, Brillouin scattering in liquids which show characteristic structures at molecular level near boundary or in specimen of very small amount.In the present study we established the method, "Brillouin scattering of thermal-phonon resonance" which enabled us to measure the phonons excited in a small volume-100mu m in size with 0.1% precision. The most serious problem in the light scattering experiment near boundaries would be the stray light which is must stronger than the weak signal light. To avoid this harmful effect, we developed a technique of polarization modulation for lock-in detection by which the spectrum of low-angle scattering(rheta-1ﾟ)was clearly observed with sufficient accuracy.The new method established in this study is being applied for studying dynamics of soft materials, yielding several interesting results. The method made a breakthrough to the Brillouin scattering which has more than 30 years history.

在以前的研究中，我们已经成功地将光学拍频光谱技术引入到布里渊散射实验中。实现了比以往实验高100到1000倍的分辨率。该技术为研究软材料中的各种分子动力学现象提供了一种非常有效的手段，包括：(A)首次观察到布里渊三重态的真实形状，(B)高度各向异性分子中退偏振光散射的异常谱形，以及(C)观察到材料中非平衡状态下布里渊峰的斯托克斯和反斯托克斯分量之间的不对称。本研究的目的是将这一新技术应用于研究热-声子共振，这一奇怪的现象是限制在有限空间中的自然声子揭示共振效应。我们试图描述这一现象的物理机制并找到它的应用，例如，在边界附近的分子水平上表现出特征结构的液体中的布里渊散射，或者在极少量的样品中。在本研究中，我们建立了热-声子共振的布里渊散射方法，使我们能够以0.1%的精度测量小体积-100微米尺寸的声子激发。在边界附近的光散射实验中，最严重的问题是杂散光，它必须比微弱的信号光强。为了避免这种有害的影响，我们发展了一种用于锁定检测的偏振调制技术，利用该技术可以足够准确地观察到低角散射(Rheta-1ﾟ)的光谱。本研究建立的新方法被应用于软材料的动力学研究，产生了一些有趣的结果。该方法突破了已有30多年历史的布里渊散射。

项目成果

T.Ueno,K.Sakai,K.Takagi: "Simple and Coupled Process Reorientational Relaxation in Isotropic Phase of 6CB" Phys.Rev.E. 54. 6457-6461 (1996)

T.Ueno、K.Sakai、K.Takagi：“6CB 各向同性相中的简单耦合过程重定向弛豫”Phys.Rev.E。

T.Ueno, K.Sakai, K.Takagi: "Simple and Coupled Precesses of Reorientational Relaxation in Isotropic phase of p-n-hexylp'-cyanobiphenyl" PHYSICAL REVIEWE. 54. 6457-6461 (1996)

T.Ueno、K.Sakai、K.Takagi：“对-正己基-氰基联苯各向同性相中重新定向弛豫的简单和耦合过程”物理评论。