The near- and mid-infrared emission properties of Tm3+-doped GeGaS–CsI chalcogenide glasses

Serials of chalcogenide glasses based on composition of 72GeS2–18Ga2S3–10CsI (in mol%) and doped with high Tm3+ content (up to 10,000 ppm) were prepared, and their luminescence properties were investigated under excitation with 800 nm laser. The influences of doping concentration on Judd–Ofelt intensity parameter Ωi, spontaneous transition probability A, fluorescence branching ratio β, and radiative lifetime τrad of Tm3+ in the samples were studied. Four infrared emission bands observed were centered at 1.48, 1.8, 2.3, and 3.8 μm, corresponding to optical transitions 3H4 → 3F4, 3F4 → 3H6, 3H4 → 3H5 and 3H5 → 3F4, respectively. For 1.0 wt.% Tm3+: doped sample, no concentration quenching was observed and its emission cross-sections at 2.3 and 3.8 μm calculated by using Füchtbauer–Ladenburg equation were 6.85 × 10−21 and 7.66 × 10−21 cm−2, respectively.