Spectroscopic investigations on Tb3+ doped lead fluoroborate glasses

Abstract

This article presents the optical properties of Tb3+ in lead fluoroborate glasses of the type X PbF2·(89–X)B2O3·10 Al2O3·1Tb2O3 (where X=8, 12, 16, 20, 24, 28, 34 and 36). The standard Judd–Ofelt model was applied to the room temperature absorption intensities of Tb3+ (4 f8) to determine the phenomenological intensity parameters Ω2, Ω4 and Ω6. These parameters have been used to calculate radiative transition probabilities (Arad), lifetimes (τR) and branching ratios (βR) for the excited level 5D4. The predicted values of τR are compared with the measured values for 5D4 level for eight glass compositions (Glass (A–H)). Among the eight-terbium glasses Glass A with 8 mol% of PbF2 (as the optimum content) has revealed an intense green emission with maximum life time and higher quantum efficiency. The stimulated emission cross section σ(λP) is also evaluated for the 5D4→7FJ (J=6, 5, 4 and 3) transitions.