Absorption and mid-infrared emission spectroscopy of Dy3+ in Ge-As(or Ga)-S glasses

Ge-As-S and Ge-Ga-S glasses doped with Dy3+ were prepared and the emission characteristics of four infrared fluorescent emissions al 1.33, 1.75, 2.90 and 4.38 mu m were evaluated. High oscillator strengths and large intensity parameters of Dy3+ originate from the highly covalent nature of the bonds in the glasses, Measured lifetimes in the Ge-As-S glass are 728 and 4550 mu s for the H-6(11/2) --> H-6(15/2) (1.75 mu m) and H-6(13/2) --> H-6(15/2) (2.90 mu m) transitions, respectively. Quantum efficiencies of 32.8 an 87.2% of the above transitions compare well with the values reported previously. Multiphonon relaxation rates in Ge-As-S and Ge-Ga-S glasses are similar to 4 orders of magnitude less than those in silicate glasses, which provide good opportunities for future laser applications.