Intensity of the Raman light scattering by polaritons and dispersion of the nonlinear susceptibility near lattice resonances in an LiIO3 crystal

The angular and frequency distributions of the intensity of the Raman light scattering by polaritons in an LiIO₃ crystal were studied for various scattering geometries using an optical multichannel analyzer. The intensity measurements were used to obtain the dispersion of the nonlinear susceptibilities χ₃₂₂(v) and χ₃₂₁(v) near crystal lattice resonances and to determine the appropriate constants. It was found that the relationship between the Kleinman allowed and forbidden components of the nonlinear susceptibility tensor changes substantially as the frequency of one of the interacting waves approaches the lattice resonance region.