Model for Brillouin Scattering in Amorphous Solids

Abstract An elastic continuum model is presented for Brillouin scattering by an amorphous solid. The assumption that light scatters on distorted plane wave acoustic phonons leads to the prediction that the scattered intensity plotted as a function of the frequency transfer Ω o consists of the usual Brillouin peaks plus a background which, a t room temperature, goes like Ω o ; for small Ω o , but rises less steeply for larger Ω o , and may even bend over within the range of the validity of the model, depending on the correlation lengths for spatial fluctuations due to disorder and on the speeds of sound. For the case of a‐Si, additional results are obtained with the help of existing experimental measurements.