Spectroscopic characterization of alkali modified zinc-tellurite glasses doped with neodymium

Neodymium doped zinc-tellurite glasses of composition TeO2–ZnO–Na2O–Li2O have been prepared and characterized for their thermal, structural and optical properties. 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 for 4F3/2 → 4I9/2, 11/2, 13/2 transitions. The quantum efficiency of the 4F3/2 level is comparable to the typical values obtained for the Nd2O3-doped glasses. The decay properties for higher concentration of Nd2O3 were analyzed using Inokuti–Hirayama model to investigate the non-radiative relaxation of the 4F3/2 emitting level. The experimental values of branching ratio and saturation intensity of 4F3/2 → 4I11/2 transition and calculated spectroscopic quality factor indicate the favourable lasing action in these glasses.