~2 μm emission properties and non-radiative processes of Tm3+ in germanate glass.

In this paper, 80GeO2-8Ga2O3-10BaO-2Nb2O5-6PbO (in mol%) glass samples with different Tm2O3 concentrations (0, 0.5, 0.75, 1, 1.25, and 1.5 mol. %) were prepared by traditional meltquenching method. According to the measurement of thermal properties of the host glass, the glass transition temperature is 596.7 °C and no crystallization peak is observed. Judd-Ofelt parameters Ωt (t=2, 4, 6) and fluorescent lifetimes were obtained by Judd-Ofelt theory. The similar values of Judd-Ofelt parameters and the full-width at half-maximums of ~1800 nm indicate the local environment of Tm3+ changes little with increment of Tm2O3 concentrations. Maximum stimulated emission cross-section of ~1800 nm is 6.22×10-21 cm² as calculated by Fuchtbauer-Ladenburg formula. Energy migration among Tm3+ ions was analyzed by the extended overlap integral method. The non-radiative transition rates between mainly energy levels of Tm3+ were calculated. Non-radiative transition rate of ³F4 energy level caused by OH was analyzed by rate equation and deduced by fitting the fluorescence decay curve. [ABSTRACT FROM AUTHOR]