Judd–Ofelt parameters and radiative properties of Sm3+ ions doped zinc bismuth borate glasses

Glasses having composition 20ZnO·xBi2O3·(79 − x)B2O3 (15 ⩽ x ⩽ 35 mol%) and doped with 1 mol% Sm3+ 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 Sm3+ ions to evaluate various intensity parameters (Ω2, Ω4, Ω6). The variations in intensity parameters, radiative transition probabilities and hypersensitive band positions with composition have been discussed. The variation of Ω2 with Bi2O3 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 Ω6 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 Bi2O3 content due to increased interaction between the Sm3+ ion and non-bridging oxygens. The radiative transition probabilities for the Sm3+ ions are large in zinc bismuth borate glasses, suggesting their suitability as laser material.