OBSERVATION OF STIMULATED SURFACE-ENHANCED RAMAN-SCATTERING THROUGH GRATING EXCITATION OF SURFACE-PLASMONS

We report on an experiment with surface-enhanced Raman scattering on g ratings overcoated by copper phtalocyanine that shows that, because of the resonant excitation of surface plasmons, a stimulated Raman scatt ering process occurs. The corresponding threshold value of the pump po wer is rather low, of the order of 40 mW. This observation was made wi th a thin (5-nm) film of copper phtalocyanine. The theoretical study i s developed by coupled-mode analysis that makes full use of the electr omagnetic resonant feature of this nonlinear interaction. (C) 1996 Opt ical Society of America