Raman scattering of light by polaritons in a paratellurite crystal

The frequency and angular spectra of the scattering of light by polaritons were determined for a TeO₂ crystal. Compensation of the electron and lattice contributions to the nonlinear susceptibility was observed in the region of ~1300 cm^–1, corresponding to the upper polariton branch. The angular and frequency scattering spectra were used to calculate the dispersion of the ordinary and extraordinary refractive indices of TeO₂ in the wavelength range from 2.5 to 9 μ.