PERTURBATION-THEORY RESULTS FOR THE DIFFUSE-SCATTERING OF LIGHT FROM 2-DIMENSIONAL RANDOMLY ROUGH METAL-SURFACES

Using the unitarity and reciprocity preserving formulation of Brown et al a perturbation treatment, correct to fourth order in the surface p rofile function, is given for the scattering of electromagnetic waves from a weakly rough, two-dimensional, random metal surface. In this fo rmulation the boundary conditions on the electromagnetic fields are sa tisfied using the extinction theorem in conjunction with the Rayleigh hypothesis and the vector equivalent of the Kirchhoff integral. The th eory is applied to, and results are presented for, several different t ypes of rough surfaces which are characterized by power spectra that a re extensions to two-dimensional random surfaces of the power spectrum of some one-dimensional random surfaces recently fabricated by West a nd O'Donnell. These surfaces, which can be realized experimentally, fa vor coherent, interferent, multiple scattering of electromagnetic wave s via surface plasmon polaritons in intermediate states, and clearly e xhibit enhanced backscattering caused by the surface plasmon polariton mechanism. Theoretical results are presented for silver surfaces at o ptical wavelengths.