Polarized light assessment of multiply scattering heterogenous birefringent media

光为我们提供了许多有关周围环境的有用信息。除了波长（颜色）和强度之外，光束的另一个有用的特性是它的偏振状态，或垂直于传播方向的电场矢量的方向。当光与物体相互作用时，它的偏振态会发生变化。因此，可以通过测量这种变化来获得物体的性质。*******偏振测量长期以来一直用于透明介质或薄材料（薄膜），以探测其结构和组成的细节。提出的工作是新颖的，在其使用偏振光定量光学厚浑浊介质。光在这种材料中所经历的大量偏转将显著地扰乱其偏振。然而，我们和其他人已经表明，即使在大量（多次）散射事件之后，仍然可以保留大量有用的偏振信息。灵敏的测量和精确的量化这种幸存的极化信号，然后产生独特的特征和“签名”的审问材料。因此，所提出的方法将进一步优化在这种有趣但技术上具有挑战性的浑浊介质中极化效应的测量和分析。该研究的长期目标是对生物组织进行准确的偏振光评估。虽然这里没有明确追求，但发展的极化方法也可以在非生物领域找到应用，例如湍流和行星大气的遥感，物体的水下表征以及恶劣（例如辐射损伤）环境中的检查。*******提出的科学和技术发展将因此(1)优化极化成像方法作为准确评估组织病理的快速指导技术（例如，在癌症手术中通过极化引导质谱检测肿瘤边缘），(2)报告难以到达的身体部位的组织功能状态和活力（例如，泌尿科的膀胱壁内部），(3)进一步了解线性和非线性偏振光混浊介质（生物组织）的相互作用，以改进组织显微镜。总的来说，这项研究计划将进一步推进基于偏振光独特优势和信息含量的有前途的光学技术，使各种令人兴奋和重要的生物医学应用成为可能

Light provides us with much useful information about our surroundings. In addition to its wavelength (colour) and intensity, another useful property of an optical beam is its polarization state, or the orientation of the electric field vector perpendicular to the propagation direction. When light interacts with an object, its polarization state will be changed. Hence the properties of the object can be obtained by measuring this change.*******Polarization measurements have long been used in TRANSPARENT media or thin materials (thin films) to probe the details of their structure and composition. The proposed work is novel in its use of polarized light for quantifying optically thick TURBID media. The numerous deflections experienced by the light in such materials will significantly scramble its polarization. However, we and others have shown that a surprising amount of useful polarization information can still be retained even after a significant number of (multiple) scattering events. Sensitive measurement and accurate quantification of this surviving polarization signal then yields unique characteristics and "signatures" of the interrogated material. The proposed methodology will thus further optimize measurements and analysis of polarization effects in such interesting but technically challenging turbid media. The long-term goal of the research is to perform accurate polarized light assessment of biological tissues. Although not explicitly pursued here, the developed polarized methods may also find applications in non-biological domains such as remote sensing of turbulent flows and planetary atmospheres, underwater characterization of objects, and inspection in harsh (e.g., radiation damage) environments. *******The proposed scientific and technical developments will thus (1) optimize polarimetric imaging methods as a rapid guidance technology for accurate assessment of tissue pathology (e.g., tumour margin detection via polarimetrically-guided mass spectrometry during cancer surgery), (2) report on tissue functional status and viability in difficult-to-reach body locations (e.g., inside of the bladder wall in urology), and (3) enable further understanding of linear and non-linear polarized light turbid media (biological tissue) interactions for improved tissue microscopy. Overall, this research program will further advance the promising optical technology based on the unique strengths and information content of polarized light, towards enabling a variety of exciting and important biomedical applications.***