Light enpolarization by disordered media under partial polarized illumination: The role of cross-scattering coefficients

Abstract

We show how disordered media allow to increase the local degree of polarization (DOP) of an arbitrary (partial) polarized incident beam. The role of cross-scattering coefficients is emphasized, together with the probability density functions (PDF) of the scattering DOP. The average DOP of scattering is calculated versus the incident illumination DOP.

Transmission versus reflectance spectroscopy for quantitation

“…It has been shown both numerically and experimentally that the average degree of polarization can increase from 0 to 0.75 when the light source is highly coherent, and the medium has little absorption compared to scattering. [35][36][37][38] It is possible that enpolarization effects could influence the comparison of reflectance and transmission, especially when the two modes have very different pathlength distributions, and this potential should be investigated in future experimental work.…”

Spatial depolarization of light from the bulks: electromagnetic prediction

“…Additional complexity was brought by the introduction of random media, hence mixing spatial and temporal disorders [10][11][12]. Specific effects were recently emphasized at the speckle size, like the local (temporal) enpolarization of light [13][14][15], and the multi-scale (spatial) depolarization [11,12,16]. Most effects were confirmed by experiment [16][17][18][19], which justifies a motivation to go further in these fields.…”

“…Previous works [11,13,15] have shown that because the illumination is perfectly monochromatic and fully polarized, full temporal polarization is guaranteed for the scattered field at any space location, so that temporal averages vanish in Eq. (4) and mutual coherence of the scattered field can be turned as:…”

“…In all situations the behavior of the far field pattern is intimately connected with the sample microstructure, which drives the angular, spectral and polarization properties. Recent examples give a detailed analysis of the polarization degree at the speckle size in the far field [11,12,16,25], and emphasize spatial depolarization [11,16,26] and temporal repolarization [14,15] of light, all phenomena which strongly depend on the samples microstructure (roughness, inhomogeneity). Applications were also found for biological tissues and others.…”

“…Such description of the scattering process is very practical and allowed to reveal unexpected phenomena such as the en-polarization process [14,15]; also, it allowed to predict a spectral depolarization [3,28] responsible for strong modification of the polarization degree (dop) histograms [13], as well as the modification of time coherence [29] in disordered media. However this phenomenological model is valid for highly heterogeneous samples and fails at intermediate electromagnetic regimes, whereas these regimes occur in numerous situations.…”