Low-frequency Raman scattering from CdS microcrystals embedded in a germanium dioxide glass matrix

Abstract
We report here results from experiments on low-frequency Raman scattering from CdS microcrystals of various sizes embedded in a germanium dioxide glass matrix. We observed peaks in the low-frequency region in the tail parts of the Rayleigh lines and we found that the frequencies of these peaks were proportional to the inverse microcrystal diameters and that the size dependences of the peak shifts agreed fairly well with the calculated results based on Lamb’s theory. Furthermore, we found that these Raman-scattering spectra had the characteristic polarization properties. Our results show that the observed low-frequency Raman scattering originates from confined acoustic vibrations of a spherical CdS microcrystal.