Effect of P2O5 addition on structural and luminescence properties of Nd3+-doped tellurite glasses

Abstract

Effect of P2O5 addition on spectroscopic properties of trivalent neodymium (Nd3+)-doped tellurite glasses was studied through Raman, absorption, emission and decay measurements. Raman spectra (350–1250 cm−1) of the Nd3+-doped tellurite glasses with various P2O5 concentrations, were obtained upon 514 nm Ar+ laser excitation and found that bandwidth of the intense band increased with the addition of P2O5 from 0 to 20 mol%, indicating the transformation of TeO4 into TeO3+1 and TeO3 units. Judd-Ofelt intensity parameters and radiative properties of luminescent 4F3/2 level were evaluated using absorption spectra for all the glasses. Luminescence spectra were measured in the region 840–1500 nm under 806 nm diode laser excitation. The decay curves for the 4F3/2 level of Nd3+ ion were recorded under 806 nm diode laser excitation by registering the emission at 1058 nm and the lifetime has been found to increase from 188 μs to 249 μs when P2O5 concentration increased from 0 to 20 mol%. The figure of merit and quantum efficiency were evaluated and compared to the other reported Nd3+-doped glasses. The results indicate that the investigated phospho-tellurite glasses could be useful as laser gain media around 1060 nm.