Multiphonon and cross relaxation phenomena in Ge-As(or Ga)-S glasses doped with Tm3+

Abstract

Multiphonon and cross relaxation phenomena in Tm3+-doped Ge30As10S60 and Ge25Ga5S70 (at%) glasses were evaluated and compared with other glass hosts. Multiphonon relaxation rates, as obtained from the measured and predicted radiative lifetimes, were orders of magnitude less than those in most oxide glasses. Cross relaxation associated with H-3(4), H-3(6) --> F-3(4), F-3(4) transitions was less significant in Ge25Ga5S70 glass than in Ge30As10S60 glass and were comparable to those in fluoride glasses. Oscillator strengths and intensity parameters of Tm3+ in both sulfide glasses were larger mainly due to the covalent nature of bonds in glasses.