Abstract
A detailed theory of the scattering of light by acoustic surface ripples arising from both bulk and surface phonons in solids is given. The measured Brillouin spectra of Al, Ni, GaAs and GaP are presented. The experimental results are compared with theoretical predictions for the ripple scattering mechanism. This mechanism is dominant for Al and Ni, where there is good agreement between theory and experiment for the spectral distribution and angular dependence of the intensity, but poor agreement for the absolute cross section. The alternative scattering mechanism by way of the elasto-optic effect is shown to be important in GaAs and GaP, although in the latter the scattering from surface phonons is still apparently dominated by the ripple mechanism.