POLARIZATION DISCRIMINATION OF COMPLEX-SURFACES BY LASER-LIGHT - THEORY

Remote discrimination of the local electronic conductivity-sigma (material discrimination) and coordinate function of a conducting surface Z(x, y) (geometry discrimination) based on polarization-dependent scattering of laser light is investigated numerically and its limitation and utility are assessed. In the far-field region and under certain conditions of target distance and undulation and light wavelength and diffraction limit, our study singles out a unique set of two orthogonal polarizations (phi, phi + pi/2) of the incident light for which the spatial distribution of the "ratio" of backscattered intensities, P(s)(phi)/P(s)(phi + pi/2 ), strongly correlates with <Z>, averaged on the illuminated area of Z. The "absolute" distributions, P(s)(phi) and P(s)(phi + pi/2), do not correlate with <Z>. Determination of phi, with a polarization rotator at the laser source for a representative number of points on Z, enables the remote determination of the orientation of the surface normal <n(Z)> and, under the conditions studied, provides a measure of the third dimension that cannot be inferred from intensity-dependent imaging of a remote surface.