Spectroscopic investigations of 1.06 μm emission in Nd3+-doped alkali niobium zinc tellurite glasses

Thermal, structural and optical properties of Nd3+ ions in tellurite glass (TeO2-ZnO-Na2O-Li2O-Nb2O5) have been investigated. Differential thermal analysis revealed reasonably good forming tendency of the glass composition. FTIR spectra were used to analyze the functional groups present in the glass. Judd-Ofelt intensity parameters were derived from the absorption spectrum and used to calculate the radiative lifetime, branching ratio and stimulated emission cross-section of the F-4(3/2) -> I-4(9/2), (11/2), (13/2) transitions. The quantum efficiency of the F-4(3/2) level is comparable as well as higher than the typical value of the other tellurite based glasses. The decay from the F-4(3/2) level is found to be single exponential for different concentrations of Nd3+ ions with a shortening of lifetime with increasing concentration. The experimental values of branching ratio and saturation intensity of F-4(3/2) -> I-4(1/2) transition indicate the favourable lasing action with low threshold power. (C) 2010 Elsevier B.V. All rights reserved.