Optical characterization, infrared emission and visible up-conversion in Er3Â + doped tellurite glasses

In this work, Er3 + doped tellurite glasses have been prepared with the composition (82.5-x) TeO2 + 4.5Bi2O3 + 11.5ZnO + 1.5Nb2O5 + x Er2O3 (x = 0.1, 0.3, 0.5, 0.7, 1.0 mol%) by melt-quenching method and their physical, spectroscopic properties were investigated. The experimental oscillator strengths (fexp) of individual absorption peaks are used to estimate the Judd-Ofelt intensity parameters (Ωλ, λ = 2, 4, 6). Judd-Ofelt intensity parameters are used to calculate the spontaneous transition probabilities, radiative lifetimes and branching ratios for certain excited states of Er3 + ions. NIR emission and visible up-conversion luminescence were observed at room temperature for all glasses by exciting with 980 nm laser radiation. The emission characteristics such as peak stimulated emission cross section, FWHM, figure of merit, optical gain cross sections and measured lifetimes have been obtained for the observed Er3 +: 4I13/2 → 4I15/2 transition in the above glass composition for all the concentrations and are compared with that of the reported. Finally, NIR to visible energy conversion has been analyzed for all glasses excited at 980 nm and suitable mechanism was proposed.