Second harmonic generation during excitation of surface waves at a periodic metal–nonlinear crystal interface

Systematic allowance for the anisotropy of a nonlinear medium during the excitation of surface electromagnetic waves (SEWs) at a metal grating can substantially improve the second harmonic generation efficiency in this geometry. Two amplification mechanisms have been identified. One of these is associated with resonant excitation of SEWs at twice the frequency whilst the second is due to the satisfaction of the phase matching conditions for waves propagating in an anisotropic medium along the interface.