Raman Scattering from Surface Polaritons in a GaAs Film

Abstract

We have observed the Raman scattering from surface polaritons in a thin film (≈ 2500 Å thick) of GaAs on a sapphire substrate. The mode frequency varies as a function of the scattering angle from the TO phonon frequency of GaAs, ${\omega }_{\mathrm{TO}}=270\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, corresponding to forward scattering, to the asymptotic value of 283 ${\mathrm{cm}}^{-1\mathrm{}}$, corresponding to a large scattering angle. The dispersion of the mode frequency was found to be appropriate for the surface polariton of a GaAs film bounded by a sapphire substrate on one side and by air on the other side.