We report the investigation of Brillouin scattering from thermal surface acoustic waves on Ag-coated holographic gratings. The usual wave-vector conservation condition for Brillouin scattering is modified due to the added periodicity in the direction of phonon propagation, but this effect is observed only when surface plasmons act as an intermediate state in the scattering process. The involvement of surface plasmons results in an enhancement of the Brillouin scattering cross section which depends on the grating amplitude.

• Received 20 January 1989

DOI:https://doi.org/10.1103/PhysRevB.40.4153