Judd–Ofelt parameters and radiative properties of Sm 3+ ions doped zinc bismuth borate glasses

Abstract

Glasses having composition 20ZnO· xBi 2O 3·(79 − x)B 2O 3 (15 ⩽ x ⩽ 35 mol%) and doped with 1 mol% Sm 3+ ions have been prepared by melt quench technique. Optical absorption and fluorescence spectra have been recorded. Judd–Ofelt approach has been applied for the f ↔ f transition of Sm 3+ ions to evaluate various intensity parameters ( Ω 2, Ω 4, Ω 6). The variations in intensity parameters, radiative transition probabilities and hypersensitive band positions with composition have been discussed. The variation of Ω 2 with Bi 2O 3 content have been attributed to change in the asymmetry of the ligand field at the rare earth ion site and to the changes in their rare earth–oxygen ( RE–O) covalency, whereas the variation of Ω 6 is found to be strongly dependent on nephlauxetic effect. The shift of the hypersensitive band shows that the covalency of the RE–O bond increases with increase of Bi 2O 3 content due to increased interaction between the Sm 3+ ion and non-bridging oxygens. The radiative transition probabilities for the Sm 3+ ions are large in zinc bismuth borate glasses, suggesting their suitability as laser material.