混浊介质偏振光传输特性的研究
文献类型：学位论文
| 作者 | 程欣 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 王向朝 |
| 关键词 | 混浊介质 光传输 光散射 偏振 |
| 其他题名 | Research on the propagation of polarized light in turbid media |
| 中文摘要 | 光学理论及其应用的发展贯穿着一个基本问题，即光的产生、传输以及接收和应用都涉及光与介质的相互作用和相互影响，也就是光在介质中的传输问题。混浊介质中偏振光传输的研究是光传输领域一个新的研究热点，相关研究在空间光通信、大气遥感、对地观测与对空监视、生物医学光子学等领域具有重要的理论指导意义以及广阔的应用前景。本文重点研究了偏振光在气液溶胶以及生物组织中传输的相关理论问题。主要研究分为以下几个方面： 1.详细分析了球状气液溶胶质粒光散射的偏振特性。在特定的散射角，确定了最大偏振度所对应的波长。利用Lorenz-Mie-Debye理论来描述气液溶胶质粒的光散射过程。通过对纯水构成的气液溶胶质粒在自然光入射情况下散射光特性的研究，确定了不同波段最大偏振度及其对应波长。最大偏振度及其对应波长的确定为偏振光导航定位系统设计过程中滤光片的选择和旋转平台的设计提供了参考依据。 2.研究了球形粒子对偏振高斯光束的散射作用，理论上确定了基模偏振高斯光束入射球形散射粒子散射光强的角分布特征。用矢量电磁场Hertz矢量对偏振高斯光束进行表征，利用T矩阵给出散射过程的物理表述。通过对纯水构成的气液溶胶质粒散射偏振高斯光束的研究，确定了形貌共振区域以及强度平滑区域的角度范围。 3.研究了群聚气液溶胶质粒光散射偏振特性，给出群聚气液溶胶体系可见光范围内的散射光强度以及偏振度的角分布特性。用对数正态粒子谱来表征气液溶胶质粒的群聚特性，可见光范围内对应于不同波长的折射率由分段差值方法数值计算得到。对于不同散射角散射光强度以及偏振度的研究表明，形貌共振导致的强度尖峰随着波长的增加而消失。 4.研究了混浊介质Mueller矩阵的对称特性。基于单次散射理论，给出前向散射和后向散射Mueller矩阵的解析表述以及Mueller矩阵各元素的强度轮廓。研究表明，镜像作用导致前向散射和后向散射Mueller矩阵的对称性发生变化，特征元素M31与M13的对称结构变化尤为明显。研究结果澄清了目前对背向散射Mueller矩阵研究的模糊认识，为进一步研究混浊介质前向散射奠定了理论基础。 5.提出了一种基于四元代数(Quaternion)的Stokes矢量旋转方法。首先研究了基于四元代数的基矢旋转，然后在此基础上给出四元数定义下的Stokes矢量，并构造了Stokes-Poincaré空间来容纳四元数Stokes矢量，最后给出在Stokes-Poincaré空间中四元数旋转的解析表述。研究表明，在相同PC设置与相同参数设定的前提下，基于该方法的Monte Carlo程序运算时间明显缩短。 6.提出了一种描述混浊介质透射光传输的三阶散射近似模型。传输过程中能量损耗由Beer-Lambert定律给出，基于Henyey-Greenstein相函数，给出三次散射的联合概率密度函数。结合散射路径的几何限制，利用数值求解的方法确定联合概率密度函数的极值，进而确定最大概率散射路径。用最大概率散射路径近似代替偏振光在混浊介质中的传输路径，进而给出其前向散射光的Mueller矩阵强度分布函数。参考Monte Carlo方法计算结果，该前向散射三阶近似模型完全可以描述Mueller矩阵16个元素的角向以及径向强度分布特征。 |
| 英文摘要 | Light propagation in media is the most fundamental problem which has been penetrating the integral development of optics and its applications. Light generation, light propagation as well as light receiving all involve the light-matter interaction that is the key problem for light propagation in media. Investigation to the light propagation in turbid media is one of the latest trends in the realm of light propagation, and related researches have potential applications in Space Optical Communication, Atmospheric Remote Sensing, Earth Observing and Space Monitoring as well as Biomedical Photonics and so on. The main objective of this thesis is to explore the propagation of polarized light in the model of aerosols and tissue phantoms. The main points of this thesis are as follows: i.Analyze the polarization of light scattered by an aqueous aerosol particle and ascertain wavelengths at the maximum Degree of Polarization (DOP). Lorenz-Mie-Debye theory constitutes the theoretical basis. Under assumption of natural light illumination, we ascertain the maximum DOP according to different spectrums of visible light. ii.Analyze the scattering action of a spherical particle on polarized Gaussian beam (TEM00 mode) and give angular intensity distribution of the scattered polarized Gaussian beam. Polarized Gaussian beam is presented using Hertz vectors and the scattering process is illustrated by T matrix theory. Take aqueous particle as an example, we ascertain the Morphology Dependent Resonances (MDRs) zone and the smooth vibration zone of the intensity. iii.Analyze the light scattering by a cluster of aqueous aerosol particles and ascertain the wavelength-dependent distribution of intensity and DOP. A Log-normal size distribution function is adopted to describe assembling state of particles. The wavelength-dependent complex refractive index is calculated using piecewise interpolation. Investigations to the intensity and DOP under different wavelengths and scattering angles demonstrate that the spike structure disappears with the increase of wavelengths. iv.Investigate the symmetric structure of Mueller matrix. Based on the single scattering theorem, we deduce analytical presentations to the elements of Mueller matrix for backscattering and forward scattering, respectively. The outline of the intensity reveals that the symmetry of Mueller matrix changes obviously, especially the characterized elements M31 and M13. The investigation clarifies some ambiguous understanding in backscattering and forward scattering of turbid media. v.Propose a novel quaternion method to describe the transform of Stokes vectors between different frames. The quaternion method is derived for rigid body rotations but also provides insight into describing the rotation of Stokes vectors. A Stokes-Poincaré Space is introduced to accommodate quaternion Stokes vectors. It is demonstrated that a Monte Carlo program using quaternion algorithm can curtail running time. vi.Propose a new approximate analytical method to simulate light propagation in turbid media. Incoherent scattering of light constitutes theoretical basis. Beer-Lambert theorem is adopted to describe energy wastage; Henyey-Greenstein phase function is used to give joint probability of three successive scattering events; optimal migration paths can be obtained using variational method. Comparison with the results by Monte Carlo demonstrates that the approximation analytical method can describe the angular symmetry and radial intensity distribution. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15260]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 程欣. 混浊介质偏振光传输特性的研究[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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