Study on the Multiple Scattering Phenomena of Coherent Light by High Concentration Media

高浓度介质对相干光多重散射现象的研究

基本信息

批准号：
06650044
负责人：
ASAKURA Toshimitsu
金额：
$ 1.28万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650044/
关键词：
Multiple scattering Backscattering Weak localization of light Coherence Fractal Dynamic light scattering Brownian motion Long range correlation 粒子懸濁液二波長相関流速計測

项目摘要

The aim of the project is to reveal the statistical properties of coherent light multiply scattered by highly disordered media and to develop new techniques for extracting information about the structure and motion of multiple scattering objects.(1) Enhanced backscattering of light : The effects of the spatial coherence of incident light, the size of particles suspended in the medium, and the polarization direction of scatteredlight, on the enhanced backscattering peak were investigated theoretically and experimentally. All these parameters were found to influence strongly the shape and peak value of the enhancement. The temporal fluctuations of scattered light due to Brownian motion of particles were also evaluated, and a characteristic behavior was found for the light scattered exactly in the backward direction.(2) Multiple scattering from fractal media : Light scattered by mass-fractal random media exhibits properties that are different from those of homogeneous random media. It was … More shown that the shape of the backscattering peak peculiar to the fractal medium is formed by its characteristic scattering free-path distribution of photons inthe medium. This feature can be utilized to measure the fractal dimension of multiple scattering objects. The intensity of ballistic light was also found to provide information about the fractal structure.(3) New phenomena on strong multiple scattering : Computer simulations were performed to investigate the spatiotemporal properties of light scattered from strong scattering media in Which the waves in the medium interferewith each other at scattering points. Some new phenomena, such as contrast enhancement of the forward-scattered light intensity and negative spatial intensity correlation of the backscattered light, were revealed and their physical origins were elucidated using the crossing probability of photon path trajectories .(4) Spectral correlation methodfor fluid velocimetry : The cross-correlations of scattered light intensities with different wavelengths were measured using concentrated flowing microspheres undergoing Brownian motion. It was shown that the correlation time measured by the spectral correlation method is unaffected by the Brownian motion, its reciprocal values being proportional to the flowing velocity of the scattering medium. A new technique for velocity measurement was proposed which is applicable to dense colloidal media. Less

该项目的目的是揭示相干光的统计特性，这些光线逐渐被媒体多散射，并开发出有关多个散射对象的结构和运动的信息的新技术。（1）光线的后散射增强：事件光的空间相干性的效果，磁光的尺寸悬浮在介质中，均匀化的射击仪，并散发了散射的光线，并增强了散射的光线。发现所有这些参数都会强烈影响增强的形状和峰值。还评估了由于颗粒的布朗运动引起的散射光的暂时波动，并发现了正好散布在向后方向的光的特征性行为。（2）来自分形介质的多个散射：由质量法随机介质散射的光散射出与同质随机媒体不同的属性。 ……更多的是，分形介质特有的反向散射峰的形状是由其特征性散射的自由路径分布形成的。可以利用此功能来测量多个散射对象的分形维度。还发现弹道光的强度提供了有关分形结构的信息。（3）进行强多散射的新现象：进行计算机模拟以研究来自强散射介质的光散射的时空特性，其中散射的波浪在散射点相互干扰。揭示了一些新现象，例如向反向散射光的前散射光强度和负空间强度相关的对比增强，并使用光子路径轨迹的交叉概率阐明了它们的物理起源。（4）使用散布灯泡的散布灯光的频谱仪的光谱相关方法。接受布朗尼运动。结果表明，通过光谱相关方法测量的相关时间不受布朗运动的影响，其倒数值与散射介质的流动速度成正比。提出了一种用于速度测量的新技术，适用于密集的胶体介质。较少的