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.