Scattering of electromagnetic beams from rough surfaces

Abstract

In this paper a formalism, which leads to the exact solution of the scattering of beams of finite cross section from an arbitrary rough surface, is presented. With use of the Green theorem, a rigorous integral equation is obtained for the case where the wavelength of the incident radiation is comparable to the dimensions of the surface roughness (resonance region). Furthermore, a new explicit solution for the amplitude of the scattered field is introduced, which reduces to known expressions when the rough surface tends to a smooth surface and the beam is replaced by a plane wave. The explicit solution is applied to the particular case of gratings. Additionally, reciprocity relations for thick slit apertures in a rough-surface screen are obtained. These results are expected to be especially useful for calculating the electromagnetic field enhancement (s polarization) near rough surfaces and for the scattering of light atoms by nonperfect periodic hard surfaces.