Why a rough-surface scattering incident polarized laser light can be perceived as the depolarizing system

Abstract

The degree of depolarization of laser light scattered from an isotropic rough silicon surface and a unidirectional rough steel surface was measured with apolarometer inthe specular direction for angles of incidence from 300 to 800.Rms roughness of the surfaces was greater than laser light wavelength and less than correlation length of the roughness. For the laser light linearly polarized at a 45 angle to the plane of incidence, dependence of the measured degree of depolarization on angle of incidence has one maximum and angle of incidence corresponding to the maxima is closett-thepseudo-&ewster angle for a smooth surfaceior both the silicon and the steel. It is found experimentally that the reason for the measured depolarization is spatial variations of the azimuth and the ellipticity of the fully polarized scattered light withiira: polarometer aperture Computer simulation of the scattenng from a one-dimensional rough steel surface satisfactorily describing the dependence of the measured degree of depolarization on angle of incidence for the unidirectional rough steel surface for angles oflncidence up ta 70° inclusive shows the single scattering niake the main contribution to thei1endence ofthe measured degree ofdepolarizatian on angle of incidence.

Light depolarization in off-specular reflection on submicro rough metal surfaces with imperfectly random roughness

“…On the other hand, optical methods of depolarization analyses were developed based on the fact that depolarization happens as the roughness degree of a surface to be inspected increases from a comparatively smooth mirror to rough surface. 17 Scattering depolarization has been studied and reported in both theoretical and laboratorial researches for more than forty years, [18][19][20][21][22][23][24][25][26][27][28] observed for more than ten years during carrying out nondestructive testing (NDT) research on thin film growth, 29,30 and also the polarization extinction was analyzed by surface roughness, bulk heterogeneity, and interface scatters in the recent ten years. 31,32 However, most of them focused on analyzing samples of randomly rough surfaces and also the majority are numerical simulations.…”