Fluorescence and Judd–Ofelt analysis of Nd 3+ doped P 2O 5–Na 2O–K 2O glass

Abstract

Sodium potassium phosphate glass consisting different Nd 2O 3 concentrations have been prepared to study the effect of Nd 3+ concentration on optical absorption and fluorescence properties. From the absorption spectra, Racah ( E 1, E 2, E 3), spin-orbit ( ξ 4f) and configuration interaction ( α) parameters are calculated and reported for all the Nd 3+ doped glasses. Judd–Ofelt intensity parameters ( Ω 2, Ω 4, Ω 6) are evaluated and these parameters are used to study the covalency as a function of Nd 3+ concentration. Results show that covalency decreases with the increase of Nd 3+ concentration. By using these three intensity parameters, total radiative transition probabilities ( A T), radiative lifetimes ( τ R), branching ratios ( β) and integrated absorption cross-sections ( Σ) have been computed for certain excited states of Nd 3+ in these mixed alkali phosphate glasses for all the concentrations. From the fluorescence spectra, peak stimulated emission cross-sections ( σ p) have been calculated for the two transitions, 4G 7/2 → 4I 13/2 and 4G 7/2 → 4I 11/2 of Nd 3+ 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 Nd 3+ concentrations. From these studies, a few transitions are identified for laser excitation among various transitions.