Polarization signatures of structural anisotropy for radiative transfer in fibrous materials

Abstract

Structural anisotropy exists prevalently in complex materials. Quantitatively extracting structural information is a long-standing challenge in optical imaging. In this paper, we propose an optimized Discrete Dipole Approximation-Monte Carlo (DDA-MC) algorithm to investigate the polarized light transportation in fibrous materials, which is validated by experiments on polystyrene fibers. Based on this model, the impact of structural anisotropy of fibrous scatterers on polarized light transportation has been analyzed quantitatively. In addition, simulation results show that structural anisotropy like the orientation angle of cylinders can be deduced from polarization signatures of backscattering light distribution with different polarized incidences. Furthermore, as a label-free and non-invasive tool, the Mueller matrix polarimetry has recently demonstrated promising potential in biomedical diagnosis. By combining with the Mueller Matrix Transformation (MMT), we present how the structural characteristics of fibrous materials, including the orientation angle and deviation of fibers, can be obtained by a Mueller matrix parameter. Therefore, this study not only provides an understanding of the role of structural anisotropy in polarized light transport but also showcases new insight into the nondestructive polarization imaging to characterize fibrous materials.