Multiple-scattering effects in the second-harmonic generation of light in reflection from a randomly rough metal surface.

We present a rigorous numerical simulation analysis of the second-harmonic generation of p-polarized light in reflection from a one-dimensional, randomly rough, metal surface when the plane of incidence is perpendicular to the generators of the surface. When the incident light cannot couple to surface electromagnetic waves supported by the metal surface at the fundamental frequency, the angular distribution of the intensity of the incoherent component of the scattered light at the harmonic frequency displays either well-defined peaks or dips in the retroreflection direction and in the direction normal to the mean plane of the surface. These effects are suppressed by the direct excitation of surface polaritons at the fundamental frequency.