Resonant Light Scattering from Weakly Rough Random Surfaces and ImperfectGratings

摘要

Rayleigh's method is used in a numerical study of the light scattered from a one-dimensional, randomly rough surface on a metal illuminated by a plane wave whose direction of incidence is perpendicular to the grooves of the surface. In the regime of interest a significant component of the amplitude of the p-polarized light scattered in the far field may be attributed to the resonant interaction between the incident wave and surface polaritons. The dependence of the coherent and of the diffuse scattering on the incident wavelength, the roughness parameters, the polarization, and the angle of incidence or of scattering is considered. The conditions under which an enhanced backscattering peak may be observed are determined within the range of convergence of Rayleigh's method. A random roughness superimposed upon a periodic grating may produce enhanced backscattering at wavelengths longer than twice the period of the grating. At the wavelength and the angle at which a grating anomaly is found, the diffuse scattering may display a band or a minimum, depending on the angle of incidence.