Optical Heterodyne Spectroscopy of Light Scattering by Laser Induced Phonons

激光诱导声子光散射的光学外差光谱

基本信息

批准号：
63460062
负责人：
TAKAGI Kenshiro
金额：
$ 4.74万
依托单位：
Institute of Industrial Science, Univ. of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

The fundamental requirement in the ultrasonic spectroscopy is to observe the velocity and absorption over extensive frequency range. In the last few years, we have developed various experimental techniques, including planoconcave ultrasonic resonator and high resolution Bragg reflection (to be referred as HRB) method. The purpose of this research project is to establish a new technique which is useful for the measurement of phonon velocity and decay at hypersonic range. For this purpose, we took advantage of the light beating spectroscopy to detect the light scattering by the thermal phonons. The success of the HRB method has shown that the light beating is most effective to observe the very weak light of Brillouin scattering. In the investigation by this Grantin-Aid,we obtained various important results which are summarized as follows.(a) We established the means to measure the phonon velocity and absorption in transparent solids at the frequency range up to 2GHz. The Gruneisen constant which represents the strength of phonon-phonon interaction, was estimated for sapphire from the results of hypersonic measurement. High frequency ultrasonic property was measured in GeO_2 glass. An absorption peak due to the structural relaxation was found around 600 MHz, which yields the distribution of the double well potential of oxygen atom in glass.(b) A new optical beating technique was developed to observe Brillouin scattering by thermal fluctuation of liquid surface.The range of the measurement was extended up to 1MHz, which is one decade higher than the previous works. This technique will be a powerful means to investigate the dynamic property of liquid surface.(c) We constracted several optical heterodyne systems to detect incoherent Brillouin scattering light by thermal phonons and obtained the characteristics and performance of each system through the preliminary test with them.

超声光谱的基本要求是观察广泛的频率范围内的速度和吸收。在过去的几年中，我们开发了各种实验技术，包括Planoconcave超声谐振器和高分辨率Bragg反射（应称为HRB）方法。该研究项目的目的是建立一种新技术，该技术可用于测量声子速度和高音范围的衰减。为此，我们利用了轻击光谱法检测热声子的光散射。 HRB方法的成功表明，光跳是最有效的，可以观察到非常弱的Brillouin散射光。在该Grantin-AID的调查中，我们获得了各种重要结果，这些结果总结如下。（a）我们确定了在频率范围至2GHz的透明固体中测量声子速度和吸收的手段。从高超音速测量的结果中估计了代表声子相互作用的强度的Gruneisen常数。高频超声属性是在GEO_2玻璃中测量的。发现由于结构弛豫而引起的吸收峰值约为600 MHz，从而产生了玻璃中氧原子双井潜力的分布。（b）开发了一种新的光学跳动技术来观察Brillouin液体表面的热波动。该测量的范围比以前更高1MHz，比以前更高。该技术将是研究液体表面的动态特性的强大手段。（c）我们求解了几个光学杂作系统，以通过热声子检测不相干的布里鲁因散射光，并通过初步测试获得了每个系统的特性和性能。