摘要本文通过米散射理论构建了宏观光学参数相同而微观光学参数不一样的5种样品，包括仿组织悬浮液，聚苯乙烯悬浮液。然后运用fortran和matlab混合编程，结合蒙特卡罗模拟和极分解技术计算无限细光束在这5种样品的后向散射面上的偏振特性。同时为使之与文献中的实验结果相对照，运用高斯变换将无限细光束的结果转化成高斯光束照射得到的结果。结果表明，模拟结果与实验结果有着一致的结论：即相同宏观光学参数而不同微观光学参数的不同样品在后向散射面上的偏振特性分布是不一致的。这说明样品的微观光学参数如密度、样品颗粒大小等可以导致样品的偏振特性呈现不一样的变化。根据这些变化，我们可以更好地判断选用何种样品对实际的生物组织进行模拟。这些结果为将偏振光应用于医学起着重要的参考价值。65344

毕业论文关键词   米散射 瑞利散射 线性退偏度 圆退偏度 蒙特卡罗模拟 

毕业设计说明书（论文）外文摘要

Title Numerical simulation for the polarization characteristics of different turbid media with the same macro optical parameters

Abstract

In this paper, Mie scattering theory is used to construct 5 kinds of simulation samples, which have the same macroscopic optical parameters with different microscopic optical parameters, including intralipid suspensions and polystyrene suspensions. Then using the fortran and matlab mixed programming, the polarization characteristics on the backscattering planes of the five samples were calculated with the Monte Carlo simulation and Mueller polar decomposition. At the same time in order to match the experimental results in literature, the results for the infinitely narrow beam were convolved to the ones for the Gaussian beam by use of Green's function. It turns out the same conclusion for both the simulated and the experimental results: they will show the different polarization characteristics on the backscattering plane of the turbid media, even if the samples have the same optical parameters, but with the  different microscopic optical parameters. This shows the micro optical parameters of the samples, such as refractive index ratio between particle and background media and the diameter of the particle are the mainly responsible factors for the difference.  With the knowledge of the difference, we can select the better substitute for certain biological tissue. And these results will be used in the medical field as an important reference.

Keywords：Mie scattering; Rayleigh scattering; Linear depolarization degree; Circularity degree of depolarization; Monte Carlo Simulation

目   次 

1  绪论 .....1 

1.1  研究意义 1

1.2  研究进展 2

1.3  本文主要工作 4

2  理论基础 4

2.1  关于光散射偏振特性 4

2.1.1  偏振光及Stokes 矢量概念 4

2.1.2  Mueller矩阵概念 4

2.2  Mie散射理论概述 5

2.2.1  Mie散射理论 5

2.2.2  基于Mie散射理论的生物组织光学参数的计算公式 8

2.3  HG相函数 8

2.4  Mueller矩阵极分解理论 9

3  偏振光在浑浊介质中的蒙特卡罗模拟 12