Investigation of mid-IR luminescence properties and energy transfer in Dy3+-doped and Dy3+, Tm3+-codoped chalcohalide glasses

•The properties of Ge–Ga–S–AgI glass with rare earth ions have been reported.•We examine quality changes in the glasses with different level of ions content.•Strong 4300 nm emission is found in the Dy3+/Tm3+ codoped glass.

A series of Dy3+-doped and Dy3+/Tm3+-codoped chalcohalide glasses (72GeS2·18Ga2S3·10AgI) were prepared. The optical properties of the glasses, including Judd–Ofelt strength parameters, transition probabilities, excited state lifetimes, fluorescence branching ratios and emission cross-sections were calculated based on the absorption and emission spectra. For the Dy3+-doped glasses, the emission intensity at 1330 nm increases obviously with increasing of Dy3+ doping content from 0.2 to 0.5 wt.%, and the fluorescence lifetimes keep at 40 μs. The emission cross-section of the Dy3+-doped glass (0.5 wt.%) was calculated to be 4.16 × 10−20 cm2. For the Dy3+/Tm3+-codoped glasses, Tm3+ ions can absorb excitation energy and effectively transfer energy to Dy3+ ions. The intensified mid-IR emissions were observed obviously, the emission cross-sections for the codoped glasses (0.8 wt.% Dy3+ and 0.5 wt.% Tm3+) were calculated to be 1.40 × 10−20 cm2 at 2900 nm and 1.52 × 10−20 cm2 at 4300 nm, respectively.