Rough surface scattering using a source able to produce an incident beam with controlled polarization and coherence.

Abstract

We present a comparison of the first numerical and experimental results for the scattering of light from rough surfaces using a recently developed variable coherence polarimetry source that permits obtaining information on the object without having to scan over incidence or scatter angle. We present, for the first time, we believe, the application of this source to a 1D rough surface and show how to analyze the scattered field to retrieve useful information about the surface. This source uses a liquid-crystal phase modulator to control the polarization as well as the coherence of the beam illuminating the rough surface. Changing the polarization state distribution at the source plane, by controlling the phase distribution on a spatial light modulator, gives a scan of two source spots over the rough surface. The scattered beam is analyzed with a Stokes polarimeter. The Kirchhoff approximation is used to calculate the scattered Stokes vector using the experimental incident Stokes vector and intensity distribution as a source. Good agreement is obtained between the numerical and experimental results, for a simple calculation of the number of intensity maxima obtained as the two first-order source spots are scanned across the sample.