Polarized light assessment of multiply scattering heterogenous birefringent media

多重散射异质双折射介质的偏振光评估

• 批准号: RGPIN-2018-04930
• 负责人: Vitkin, Alex
• 金额: $ 7.29万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760746
• 关键词: Polarized; light; assessment; multiply; scattering

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.

光为我们提供了许多关于我们周围环境的有用信息。除了它的波长(颜色)和强度之外，光束的另一个有用的特性是它的偏振态，即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，其偏振态会发生变化。因此，可以通过测量这种变化来获得物体的性质。长期以来，偏振测量一直被用于透明介质或薄膜材料，以探测其结构和组成的细节。这项工作的新颖之处在于它使用偏振光来量化光学厚度较厚的混浊介质。光在这种材料中所经历的大量偏转将显著扰乱它的偏振。然而，我们和其他人已经证明，即使在大量(多次)散射事件之后，仍然可以保留令人惊讶的大量有用的偏振信息。对这种幸存的偏振信号进行灵敏的测量和准确的量化，然后产生被询问材料的独特特征和“特征”。因此，建议的方法将进一步优化对这种有趣但具有技术挑战性的混浊介质中偏振效应的测量和分析。这项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，但所开发的极化方法也可以应用于非生物领域，例如湍流和行星大气的遥感、物体的水下表征以及在恶劣(例如，辐射损害)环境中的检查。因此，拟议的科学和技术发展将(1)优化偏振成像方法，作为准确评估组织病理的快速指导技术(例如，在癌症手术期间通过偏振引导质谱仪检测肿瘤边缘)，(2)关于难以触及的身体位置(例如，泌尿外科的膀胱壁内部)的组织功能状态和生存能力的报告，以及(3)使人们能够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。总体而言，这项研究计划将进一步推动基于偏振光独特强度和信息含量的前景广阔的光学技术，使各种令人兴奋和重要的生物医学应用成为可能。