Mid-IR luminescence of Dy3+ and Pr3+ doped Ga5Ge20Sb10S(Se)65 bulk glasses and fibers

•The structure of Dy3+ or Pr3+ doped Ga5Ge20Sb10S(Se)65 was characterized by Raman spectroscopy and EXAFS.•Pr3+ and Dy3+ ions can be inserted in studied low phonon energy glasses, thanks to the presence of [GaS(Se)4/2]−RE complexes.•In sulfide glasses for a 1 wt% of Dy3+concentration, the Dy3+ ions is surrounded by ∼7.9±0.5 sulfur atoms.•Dy3+ or Pr3+ doped Ga5Ge20Sb10S(Se)65 fibers provide efficient emission between 3.5 and 5 μm.

Dy3+ and Pr3+ doped Ga5Ge20Sb10S(Se)65 glasses provide good emission efficiencies in the mid-infrared (mid-IR). The complex glassy network of these chalcogenide glasses were characterized by Raman scattering and extended X-ray absorption fine structure, to put in evidence a structure combining tetrahedra of Germanium and Gallium and trigonal pyramids of Antimony. The arrangement of these structural units permits the introduction of rare earth ions thanks, in particular, to a charge compensation generated by the Ga in a tetrahedral site. Consequently, Pr3+ and Dy3+ ions inserted in such low phonon energy glasses emit efficiently in mid-IR, between 3.5 and 5 μm. Finally, Dy3+ and Pr3+ doped Ga5Ge20Sb10S(Se)65 fibers were obtained from bulk glass preform. Efficient emission in mid-IR was obtained by pumping Dy3+ doped Ga5Ge20Sb10S65 and Pr3+ doped Ga5Ge20Sb10S(Se)65 fibers at 920 nm and 2 μm, respectively.