Behaviour of Isotropic Point in LiKSO4\text{}_{4} Crystals

The temperature-spectral dependencies of refractive indices and birefringence in wide temperature (77-1000 K) and spectral (250-850 nm) regions in LiKSO$\text{}_{4}$ crystals were measured. The isotropic point of LiKSO$\text{}_{4}$ crystals was investigated. It was shown that annealing and X-ray irradiation display insignificantly the isotropic point to a visible region of spectrum