Fluorescence and Judd-Ofelt analysis of Nd3+ doped P2O5-Na2O-K2O glass

Sodium potassium phosphate glass consisting different Nd2O3 concentrations have been prepared to study the effect of Nd3+ concentration on optical absorption and fluorescence properties. From the absorption spectra, Racah (E-1, E-2, E-3), spin-orbit (xi(4f)) and configuration interaction (alpha) parameters are calculated and reported for all the Nd3+ doped glasses. Judd-Ofelt intensity parameters (Omega 2, Omega 4, Omega 6) are evaluated and these parameters are used to study the covalency as a function of Nd3+ concentration. Results show that covalency decreases with the increase of Nd3+ concentration. By using these three intensity parameters, total radiative transition probabilities (A(T)), radiative lifetimes (tau(R)), branching ratios (beta) and integrated absorption cross-sections (Sigma) have been computed for certain excited states of Nd3+ in these mixed alkali phosphate glasses for all the concentrations. From the fluorescence spectra, peak stimulated emission cross-sections (sigma(p)) have been calculated for the two transitions. (4)G(7/2) -> I-4(13/2) and (4)G(7/2) -> I-4(11/2) of Nd3+ in all these glass matrices. From the absorption spectra, the optical band gaps (E-opt) for both direct and indirect transitions have been obtained. All these spectroscopic parameters are compared for different Nd3+ concentrations. From these studies, a few transitions are identified for laser excitation among various transitions. (C) 2009 Elsevier B.V. All rights reserved.