Refractive Parameters and Band Energy Structure of K2SO4 Crystals Doped with Copper

Potassium sulfate crystals with a copper content of 1.7% were synthesized, and the dependence of their refractive indices ni(λ) and birefringence Δni(λ) on their dispersion was studied. It was found that the dispersion ni(λ) in the spectral range of 300–700 nm is normal while introduction of the impurity leads to a decrease of ni and of the electron polarizability. The band energy structure of potassium sulfate crystal doped with 1.7% of Cu2+ was calculated. Introduction of the impurity leads to a decrease in the forbidden band width (Eg = 5.3 and 4.9 eV for pure and doped crystals respectively). The optical functions of doped potassium sulfate crystals were calculated.