Surface plasmon enhanced SFG and FWM of femtosecond pulses of non-sinusoidal metal grating

Summary form only given. In this work to study the spatial energy concentration and localization we excite surface electromagnetic waves (SEW) at the metal interface- surface plasmons if the phase matching conditions are fulfilled. Femtosecond laser pulses are used to achieve high peak intensity due to temporal pulse localization. The surface sensitivity can be enhanced with the three wave mixing process, because it is forbidden in the bulk. For spectroscopic applications three wave and four wave mixing (FWM) processes are very important. In a recent paper we suggested a new method of nonlinear signal enhancement based on interacting SEW. Here, we demonstrate for the first time the enhancement of sum frequency generation (SFG) and FWM process induced by interaction of several noncollinear SEW on the metallic grating surface.