Confocal imaging polarimetry in thick turbid media and polarization Monte Carlo

Mueller Matrix (MM) polarimetry enables the extraction of the polarization properties of biological samples with a depth resolution of a few micrometers. MM polarimetry becomes challenging with optically thick turbid media, as increased complexity and heterogeneity. We have previously proposed a multimodal imaging technique that combines Mueller matrix microscopy with nonlinear microscopy, utilizing second-harmonic generation (SHG). This enables us to extract the MM from a bulk biological sample, and the non-linear microscopy signal provides additional validation of the origin of the system's optical anisotropy. In this work, we demonstrate depth-resolved quantitative polarimetry using confocal MM microscopy in optical phantoms with microsphere suspensions as well as in fibrous tissues, to evaluate the intrinsic polarization characteristics of optically thick turbid media at different depths. Additionally, we utilize the Monte Carlo model of polarized light transfer to model the interaction of the polarized light with optical phantom for both a back-reflected MM and confocal Mueller Matrix imaging to validate our findings.