权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A Novel Chemical Measurements Using A Laser Induced Ultrasonics

使用激光诱导超声波进行新型化学测量

基本信息

批准号：
60550532
负责人：
SAWADA Tsuguo
金额：
$ 1.28万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550532/
关键词：
Laser-induced Ultrasonic Thermal Grating 微量分析プラズマ診断

项目摘要

A novel technique for evaluating a variety of newly developed chemical materials has been required to develope nowadays. From the above-mentioned view point, we have tried to apply a laser -induced ultrasonic to them. That is, using two laser beams of the same frequencies,interference pattern is produced inside materials by intersecting the two beams. In the interference region optical properties ( ie, refractive index, light absorption strength ) of the material are also spatially modulated through the interaction between light and material. In the case of light absorbing materials, the same pattern arises from the heat generated by nonradiative relaxation processes of the excited states. The spatial modulation of the heat gives rise to thermal grating and also counterpropagating acoustic waves through expansion and contraction of the heated region. A diffraction grating generated inside the materials is detected through the Bragg diffraction of another probe beam. Using the above-mentioned laser-induced thermal grating, we demonstrated some experimental results that this technique can be successfully applied to trace analysis of materials and ultrasonic spectroscopy.That is, using thermal grating, quantitative analysis of <KMnO_4> solutions in <H_2O> was carried out down to the order of <10^(-7)> M concentration. Ultrasinc waves could be generated and detected over the ranges from some MH to 100 MHz without restriction of any contact with samples and its ultrasoniz velocity was measured in liquid samples.

如今需要开发一种评估各种新开发的化学材料的新技术。从上述观点出发，我们尝试将激光诱导超声波应用于它们。即使用两束相同频率的激光束，通过两束光的交叉在材料内部产生干涉图样。在干涉区域中，材料的光学特性（即折射率、光吸收强度）也通过光与材料之间的相互作用进行空间调制。在吸光材料的情况下，激发态的非辐射弛豫过程产生的热量会产生相同的图案。热量的空间调制会产生热光栅，并通过受热区域的膨胀和收缩产生反向传播的声波。通过另一个探测光束的布拉格衍射来检测材料内部产生的衍射光栅。利用上述激光诱导热光栅，我们证明了该技术可以成功应用于材料的痕量分析和超声光谱分析。即利用热光栅对<H_2O>中的<KMnO_4>溶液进行了低至<10^(-7)>M浓度量级的定量分析。可以在 MH 到 100 MHz 的范围内产生和检测超声波，而无需限制与样品的任何接触，并且可以在液体样品中测量其超声波速度。