Modification of the Optical Properties of CaF2-TR3+ Crystals by Yttrium Impurities

Abstract
Absorption and luminescence spectra of CaF2Nd3+ (type 1) [1] crystals are investigated as a function of the concentration of added yttrium fluoride. The appearance of new lines, and a decrease in the line intensities, due to yttrium content is attributed to a shift in the equilibrium of Nd centres. Some possible models are discussed. The equilibrium of centres of rareearth ions (TR3+) in the presence of yttrium fluoride in CaF2Nd3+ crystals is calculated approximately.