Contribution of the Imaginary Part of Photoelastic Constants to Resonant Brillouin Scattering in CdS

抄録

A deep but finite minimum in the dispersion of the Brillouin scattering cross section has been found in the wavelength region of the resonant cancellation at 562.4 nm (T=300 K) in CdS. This minimum is interpreted as arising from the contribution of the imaginary part of photoelastic constant P₆₆, whose existence has been overlooked so far. The lifetime broadening is introduced to obtain the imaginary part by replacing the photon energy hω with hω+iΓ (Γ: damping energy) in the piezobirefringence theory. The damping energy is found to be Γ=0.5 meV at 300 K from the best fitting of the theoretical curve to the experimental results.