Investigation of 2.9 μm luminescence properties and energy transfer in Tm3+/Dy3+ co-doped chalcohalide glasses

A series of chalcohalide glasses based on the composition of 0.9(Ge30Ga5Se65)-0.1CsI with different Tm3+/Dy3+-codoped ions concentrations were synthesized by melt-quenching technique. The absorption spectra and 2.9μm mid-infrared fluorescence spectra of glass samples under 800 nm laser excitation were measured. The results showed that Tm3+ was an efficient sensitizer, which could enhance the Dy3+:2.9 μm fluorescence intensity significantly. The effective energy transfer between the two rare-earth ions were mainly attributed to the resonance energy transfer from Tm3+:3F4 to Dy3+:6H11/2 level. Emission cross section of 2.9 μm mid-infrared luminescence was also investigated according to Judd-Ofelt theory, σe=2.51×10−20 cm2.