Enhanced backscattering of surface polaritons on a randomly rough surface

We present a theory of the enhanced backscattering of surface polaritons on a two-dimensional randomly rough surface. We solve the scattering problem by the method of reduced Rayleigh equations using unitary and reciprocal expansions in powers of the surface profile function. We calculate the angular dependence of the intensity of the surface polaritons into which the incident surface polariton has been scattered, and find that it has a peak in the backscattering direction. The effect is expected to be most easily observed by the methods of near-field optical microscopy in the infrared range.