Analyses and applications of singular intensity variations in Gaussian scattering fields of laser light

激光高斯散射场奇异强度变化分析及应用

基本信息

批准号：
09650038
负责人：
UOZUMI Jun
金额：
$ 2.18万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650038/
关键词：
Light scattering Gaussian speckle Clustered speckle Long correlation tail Fractal speckle Doubly scattered speckle Power-law illumination Power-law intensity correlation 強度相関べき則円環状照明

项目摘要

Recently, random fields with singular properties were found in the framework of Gaussian speckles. The present study aims at analyzing statistical properties and generation conditions of such random fields through theoretical, experimental and simulation approaches.1. Generating mechanism of structured specklesStructured speckles (clustered speckles) are found to appear when a diffuser is illuminated by a thin ring-slit aperture. An isotropy of the speckle clustering was shown to be due to circular symmetry of the ring slit. An origin of speckle clustering was shown by means of computer simulations. Developing process of partially-developed clustered speckles are revealed experimentally by using small-roughness diffusers.2. Axially long spatial correlationWith relation to properties of a non-diffracting beam, it was shown theoretically that the clustered speckles produced by the ring-slit illumination have very long spatial correlations in the axial direction. The results were verified by experiments.3. Generation of fractal specklesIt was shown experimentally that a double scattering process using a random fractal diffuser and an ordinary diffuser can produce speckle intensity distributions with a fractal property in a Fourier transform plane of the second diffuser. This verified a theoretical prediction given previously. A 3D correlation properties of the speckles were also examined.4. Fractal speckles in Fresnel and image regionsIt was shown that speckle intensity distributions with fractal properties can also be generated in the Fresnel diffraction regions and in the image plane of the ordinary diffuser by using suitable configurations.

最近，在高斯散斑的框架中发现了具有奇异特性的随机场。本研究旨在通过理论、实验和仿真的方法分析此类随机场的统计特性和生成条件。 1．结构散斑的产生机制结构散斑（簇状散斑）被发现在扩散器被薄环缝孔径照射时出现。散斑聚类的各向同性被证明是由于环缝的圆形对称性造成的。通过计算机模拟显示了散斑聚类的起源。利用小粗糙度漫射体实验揭示了部分发育簇状散斑的发育过程。 2．轴向长空间相关性与非衍射光束的特性相关，理论上表明环缝照明产生的簇状散斑在轴向上具有非常长的空间相关性。通过实验验证了结果。 3．分形散斑的产生实验表明，使用随机分形漫射器和普通漫射器的双散射过程可以在第二漫射器的傅立叶变换平面中产生具有分形特性的散斑强度分布。这验证了之前给出的理论预测。还检查了散斑的3D相关特性。4．菲涅尔和图像区域中的分形散斑结果表明，通过使用合适的配置，也可以在菲涅尔衍射区域和普通漫射器的图像平面中生成具有分形特性的散斑强度分布。