PHOTOCHROMIC EFFECTS IN (LA1-XPRX)(2)S-3-CENTER-DOT-2GA(2)O(3) GLASSES

This paper discusses the experimental results from the photodarkening effect detected (La1-xPrx)(2)S-3 . 2Ga(2)O(3)(0 <X< 1) glasses. The ph otodarkening effect is stimulated by light with lambda = 0.340-0.500 m u m and manifests itself in a shift of the transmission edge toward lo nger wavelengths and in a decrease of the transmission-band intensitie s in the impurity region and is caused by energy processes of the corr esponding photons by Pr3+ ions. The resulting parameters of the quanti tative transmission variation correlate with the emissivity of the gla sses from the study of the photoluminescence spectra caused by Pr3+ io ns. The results are discussed in terms of the configuration model, whi ch assumes that the praseodymium ions exist in the ground (pr(3+)) and metastable (pr(4+)) states. (C) 1996 The Optical Society of America.