Raman spectra of thin organic films enhanced by plasmon surface polaritons on holographic metal gratings

Abstract

The variation in the Raman intensity of a thin film of polystyrene coated onto a Ag metal holographic grating has been measured as a function of the angle of incidence of the exciting laser beam. The Raman signal reaches its maximum intensity at the angle at which the laser excites the plasmon surface polariton mode of the metal directly by coupling through the grating vector. This demonstrates that plasmon surface polariton fields can be exploited to enhance the Raman spectra of very thin films on metal surfaces. The advantages of using holographic gratings in this type of experiment are briefly discussed.