Photoluminescent properties of rare-earth ions in TeO2-WO3-PbO-La2O3 glasses

The tellurite-tungstate glasses containing small amounts of rare-earth ions have been studied experimentally at 77 and 293 K using spectroscopic methods. The photoluminescence (PL) studies reveal the emission of efficient green-yellow light from Tb3+ ions and red light from Eu3+ ions. The Judd-Ofelt intensity parameters have been derived for Nd3+ and Er3+ ions from the absorption spectra and they have used to calculate the radiative lifetimes and branching ratios. The quantum efficiency η = 0.95 of the 4F3/2 level of Nd3+ ion is higher than the typical value of other tellurite-based glasses. For Er3+ ions, PL originating from the 4S3/2,4I11/2 and 4I13/2 levels has been observed and the luminescence decay of the first two levels has been found to be governed by radiative transitions and multiphonon relaxation involving the highest energy of Te-O vibrations.