Spectroscopic properties of Dy3+ ions in NaF–B2O3–Al2O3 glasses

This paper reports the optical properties of Dy3+ in sodium fluoroborate glasses of the type XNaF·(89 − X)B2O3·10 Al2O3·1Dy2O3 (where X = 8, 12, 16, 20 and 24). Judd–Ofelt intensity parameters (Ω2, Ω4, Ω6) are derived from the absorption spectra. The Judd–Ofelt theory has been applied to interpret the local environment of Dy3+ ions and bond covalency of RE–O bond. These parameters have been used to calculate radiative transition probabilities (Arad), lifetimes (τR) and branching ratios (βR) for the excited level 4F9/2. The predicted values of τR are compared with the measured values for 4F9/2 level for five glass compositions (Glass (A–E)). The stimulated emission cross-section σ(λP) are also evaluated for the 4F9/2 → 6HJ (J = 11/2, 13/2, and 15/2) transitions.