Near- and mid-infrared emissions from Dy3+ and Nd3+-doped Ga2S3–GeS2–Sb2S3 glass

Dy3+- and Nd3+-doped stoichiometric 20GaS3/2·50GeS2·30SbS3/2 glasses were prepared. Judd–Ofelt analyses were performed to estimate radiative transition parameters for the excited levels. Near- and mid-infrared emission spectra were observed and their emission bands were carefully assigned on the basis of the transition parameters and the comparison of the spectra obtained by the different excited levels. The 4.4-μm emission band from Dy3+ due to the transition, 6H11/2 → 6H13/2, had a branching ratio more than 10% and a quantum efficiency was 63% for the glass doped with 0.3 mol% of DyS3/2. The radiative transition rate of the initial level for this transition, 6H11/2, is larger than that of the final level, 6H13/2. However, the latter was more rapidly quenched at higher Dy concentration, which means that the problem of the self-termination for the four-level system could be avoided at an adequate concentration range.

► Infrared emission spectra were measured for Dy- or Nd-doped Ga2S3–GeS2–Sb2S3 glasses.
► Quantum efficiency for the 4.4-μm emission level was 63% in the Dy-doped glass.
► Final level of the 4.4-μm emission was more rapidly quenched than initial level.
► Population inversion could be possible for an adequate Dy concentration range.