Thermal stability and spectroscopic properties of Ho3+ doped tellurite-borate glasses

Abstract

Ho3+ ions doped tellurite-borate glass samples with varying compositions were prepared. The compositional dependence on phenomenological Judd-Ofelt parameters was compared in different kinds of rare earth ions doped tellurite-borate glasses. Two methods were used to obtain radiative transition probability of 5I7 level with the aim of assuring the fitting quality. The integral absorption cross-sections and line shapes corresponding to 5I8→5G6 and 5I8→5I7 transition of Ho3+ ions were investigated in tellurite-borate glasses. The obtained data indicated that the integral absorption cross-sections corresponding to 5I8→5G6 transition of Ho3+ ions mainly depended on phenomenological Judd-Ofelt parameter, Ω2, because 5I8→5G6 transition belonged to hypersensitive transitions, which led to a larger Ω2 value. The change of line shapes of absorption spectra corresponding to 5I8→5G6 and 5I8→5I7 transitions of Ho3+ ions came from the lower energy regions, which could be attributed to the changed distribution of Stark levels and thermal population.