Analysis of the spatial distribution of polarized light backscattered from layered scattering media

Abstract

The scattering of polarized light from a two layer scattering medium is investigated using Monte Carlo simulations. First order and normalized second order moments are used to analyze the spatial properties of the emerging light in different polarization states. Linearly and circularly polarized illumination is used to probe different depths. Absorption and layer thickness are varied and it is demonstrated that the determination of these values is aided by the inclusion of polarization information. The lateral and depth localization of light by polarization subtraction is also quantified. Potential applications of these techniques are burn depth and melanoma thickness measurements.

Expression of target optical properties in subsurface polarization-gated imaging

“…Polarization memory results in a higher percentage of co-polarized light returning to the surface and a greater depth until polarization is randomized for circularly polarized incident light [15,16]. However, it was apparently that neither of these conditions was present in our experiments.…”

Depth probing of diffuse tissues controlled with elliptically polarized light

“…9, by subtracting the cross-linear channel, measuring the multiple scattered (or totally depolarized) part of the signal, from the images obtained under copolarized channels, one obtains a good approximation of the polarization maintaining images, free from surface reflections if elliptical polarization is considered.…”

Depth-resolved measurements with elliptically polarized reflectance spectroscopy

“…This method assumes that the amount of multiply scattered photons is the same for the linearly and elliptically polarized light. This assumption was previously evaluated using Monte Carlo simulations and it was determined that cross-linear polarized light is a good approximation for multiple-scattered circular polarized illumination [36]. …”

“…Here, we explore the feasibility of such system that is based on the property of circular polarized light to maintain its polarization in highly scattering media at larger depths as compared to linearly polarized light due to the so called circular "polarization memory" effect [34,35] Circularly polarized light undergos small-angle, forward scattering events in diffusely scattering media with Mie scatterers that are characterized by a predominately forward scattering phase function that largely preserves helicity for long distances in a turbid medium [22,34,36]. Furthermore, it was recently demonstrated that elliptically polarized light can be used to image scattering phantoms and biological tissue at different depths by varying the degree of ellipticity from linear to circular polarization [37].…”