Brillouin Scattering from Surface Acoustic Waves in CaF sub 2 /Si Heterostructures

We report on Brillouin scattering measurements of surface acoustic waves in thin, single crystal CaF sub 2 films grown on Silicon. The insulating layers were grown on the surface of both Si (100) and Si (111) by molecular beam epitaxy with thicknesses ranging from a few hundred angstroms to 8000angstroms.