Spectroscopic properties and Judd–Ofelt analysis of Dy3 +-doped and Dy3 +, Tm3 +-codped Ge–In–S chalcogenide glasses

0.2 wt.% Dy3 +-doped and 0.2 wt.% Dy3 +, 0.5 wt.% Tm3 +-codoped (100-x)GeS2 · xIn2S3 (x = 5,10,15,20,25) chalcogenide glasses were prepared. Their spectroscopic properties were analyzed based on absorption (ranges from 500 to 3000 nm) and emission (ranges from 1000 to 4700 nm) measurements. The Judd–Ofelt strength parameters Ωt (t = 2, 4, 6) and the spectroscopy parameters Arad, β and τrad were calculated, and the σemi of the 1330, 2930 and 4320 nm fluorescences were estimated. These Dy3 +-doped and Dy3 +, Tm3 +-codoped Ge–In–S chalcogenide glasses are valuable materials for using in 1.3 μm fiber-amplifiers and 2–5 μm mid-infrared laser devices.