Diffraction of complex harmonic plane waves and the stimulation of transient leaky Rayleigh waves

This paper describes the interaction of complex harmonic plane waves on a periodically corrugated surface. It is shown that the ability of complex harmonic plane waves to stimulate leaky Rayleigh waves on a corrugated surface is similar to the ability of harmonic inhomogeneous waves to stimulate leaky Rayleigh waves on a smooth interface. Because the experimental generation of harmonic inhomogeneous waves is more complicated and less flexible than the generation of complex harmonic waves, the combination of complex harmonic plane waves with a diffraction grating therefore offers an excellent alternative. The theoretical model developed here is based on the well-known and experimentally verified complex harmonic wave theory and the famous Rayleigh decomposition of the diffracted field. The numerical examples are given for combinations of frequency and corrugation dimensions that justify the use of the Rayleigh theory. A study of the influence of a complex frequency on the generation of Scholte-Stoneley surface waves is performed as well.