Improved 2 µm broadband luminescence in Tm3+/Ho3+ doping tellurite glass

Abstract

Tm3+/Ho3+ doping tellurite glasses (TeO2-ZnO-La2O3) were prepared by applying melt-quenching technique, and the ∼2.0 µm band luminescence characteristics were examined. A broadband and relatively flat luminescence at 1600 to 2200 nm was observed in the tellurite glass co-doped by 1.0 mol% Tm2O3 and 0.085 mol% Ho2O3 under the excitation of 808 nm laser diode (LD), which is the result of spectral overlapping of 1.83 µm band of Tm3+ ions and 2.0 µm band of Ho3+ ions. Further, about 103% enhancement was acquired after the introduction of 0.1 mol% CeO2 and 7.5 mol% WO3 at the same time, which is primarily caused by the cross-relaxation between Tm3+ and Ce3+ ions together with the enhanced energy transfer from the Tm3+:3F4 level to Ho3+:5I7 level due to the increase in phonon energy. Spectral characteristics associated with the radiative transition of Ho3+ and Tm3+ ions on the basis of Judd-Ofelt theory, and the fluorescence decay behaviors after the addition of Ce3+ ions and WO3 component were analyzed to understand the broadband and luminescence enhancement. The findings in this work indicate that tellurite glass with optimal Tm3+-Ho3+-Ce3+ tri-doping combination and appropriate amount of WO3 is a prospective candidate for broadband optoelectronic devices operated in the infrared bands.