Abstract

A classical method for rough-surface scattering is the field-perturbation (Born) approximation. A recently proposed method,¹ the so-called phase-perturbation method, has been shown to possess advantages over the Born approximation. In that method a powerseries perturbation expansion is applied to the phase of the induced surface-source function, which is the unknown in an integral equation representing the extinction theorem. It is known now that this phase power series converges more rapidly than the conventional (Born) field power series. This is true particularly in the high frequency limit, i.e., when the wavelength of the incident field is small relative to the length scale associated with the surface-roughness function. This phase-perturbation approach to scattering, however, is not known to possess an inverse. In our work we directly evaluate the scattered field at a plane in the vicinity of the scattering boundary, rather than the induced source function. Within the first-order phase-perturbation approximation, the above field is found to be related to the surface-roughness function in a simple manner, which is also invertible.

© 1990 Optical Society of America