Gradual loss of polarization in light scattered from rough surfaces: Electromagnetic prediction

Abstract

Electromagnetic theory is used to calculate the gradual loss of polarization in light scattering from surface roughness. The receiver aperture is taken into account by means of a multiscale spatial averaging process. The polarization degrees are connected with the structural parameters of surfaces.

Separation of surface and bulk reflectance by absorption of bulk scattered light

“…Leekley et al [16] proposed in 1970 a method utilizing linearly polarized light, relying on the assumption that the surface reflectance retains its polarization state, whereas the bulk reflectance becomes completely depolarized. The validity of these assumptions is, however, highly dependent on the surface and bulk properties of the material, which was later reported in several studies [17][18][19][20].…”

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].…”

“…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.…”

“…We already performed [11] this kind of study for rough surfaces, that is, for surface scattering. For that we used an exact electromagnetic model based on the frontier integral [30].…”

“…For that we used an exact electromagnetic model based on the frontier integral [30]. Numerical results allowed to emphasize the multi-scale nature of the spatial polarization degree of the speckle emitted by surfaces of increasing slopes or root-mean-squares [11]. In other words, depending on the surface characteristics, it is possible to know from which receiver aperture full polarization starts to fail, due a spatial average process.…”