Polarized light propagation through scattering media: time-resolved Monte Carlo simulations and experiments.

A study of polarized light transmitted through randomly scattering media of a polystyrene-microsphere solution is described. Temporal profiles of the Stokes vectors and the degree of polarization are measured experimentally and calculated theoretically based on a Monte Carlo technique. The experimental results match the theoretical results well, which demonstrates that the time-resolved Monte Carlo technique is a powerful tool that can contribute to the understanding of polarization propagation in biological tissue. Analysis based on the Stokes-Mueller formalism and the Mie theory shows that the first scattering event determines the major spatial patterns of the transmitted Stokes vectors. When an area detected at the output surface of a turbid medium is circularly symmetrical about the incident beam, the temporal profile of the transmitted light is independent of the incident polarization state. A linear relationship between the average order of the scatters and the light propagation time can be used to explain the exponential decay of the degree of polarization of transmitted light.