Optical absorption properties of Neodymium ions (Nd$^{3+})$ doped lead boro tellurite glasses

The optical absorption properties of Nd$^{3+}$ ions in PbO-TeO$_{2}$-B$_{2}$O$_{3}$ glasses were studied as a function of PbO content varying from 30 to 70 mol{\%}. Glasses were prepared by the usual melt quench technique. Glasses were annealed at 400$^{\circ}$C for 3 hours to remove thermal strains. Annealed glass samples were then polished. In order to understand the effect of host glass on the absorption properties of Nd$^{3+}$ ions in these glasses, oscillator strength, intensity parameters and radiative transition probabilities of Nd$^{3+}$ ions were calculated using the Judd-Ofelt theory. The variation of the intensity parameters $\Omega _{\mathrm{t}}$ (t$=$2,4,6) with PbO content has been attributed to the changes in the asymmetry of the ligand field at the rare-earth ($R)$ site (due to the structural changes) and to changes in $R$-O covalency.