Resonant Brillouin scattering via free and bound excitons in CdSe

We report resonant Brillouin scattering results in CdSe. Enhancements in Brillouin scattering have been observed at both the I₂ bound exciton and the free exciton. As a result of the spatial dispersion of the exciton-polariton, the Brillouin frequencies vary with the polariton energy. From this variation of the Brillouin frequencies, we deduced the following parameters in CdSe: transverse exciton frequency =14713 cm^?1, splitting between longitudinal and transverse exciton frequencies = 4cm^?1 and exciton effective mass (perpendicular to the c-axis) =0.40 times free electron mass. The Brillouin linewidths were found to vary with polariton energies in qualitative agreement with the theory of Brenig, Zeyher and Birman.