EFFECT OF THE METAL-FILM THICKNESS ON SURFACE-PLASMON-ENHANCED RAMAN-SCATTERING IN AN ATTENUATED TOTAL-REFLECTION EXPERIMENT

We present the measured dependence of the Raman intensity on the thick ness of the metal film in a Kretschmann geometry when surface plasmons are excited. To perform our work, we deposited a Ag film of varying t hickness onto a prism, and then we coated it with a thin layer of copp er phthalocyanine. We show that the maximum of the Raman signal is ach ieved for an overall optimization of the coupling at both pump and Sto kes frequencies, demonstrating the simultaneous excitation of surface plasmons at these two frequencies.