1.48-mu m emission properties and energy transfer between Tm3+ and Ho3+/Tb3+ in Ge-Ga-As-S-CsBr glasses

Abstract

Emission properties of Tm3+ in (0.85-x)(Ge0.25As0.10S0.65)-0.15GaS(3/2)-xCsBr glass (x=0-0.17) were investigated. With 15 mol % CsBr addition, the emission intensity of 1.48-mu m increased accompanied by a large increase in the lifetime of the Tm3+:H-3(4) level up to 1.2 ms. At the same time, a 1.48-mu m emission peak splits into two peaks due to the changes in the local structure surrounding Tm3+ ions. To achieve population inversion in Tm3+ ions, Ho3+ or Tb3+ were codoped into 0.70 (Ge0.25As0.10S0.65)-0.15GaS(3/2)-0.15CsBr glass. The population of the Tm3+:F-3(4) level was effectively quenched with Ho3+ or Tb3+ codoping. Critical distances of Tm3+:F-3(4)-> Ho3+:I-5(7) and Tm3+:F-3(4):-> Tb3+:F-7(0,1,2) energy transfer were 9.1 and 12.7 angstrom, respectively. The population density differences were higher with Ho3+ codoping than with Tb3+ due to the crossrelaxation of Tm3+:H-3(4)-> H-3(5) to Tb3+:F-7(6)-> F-7(3). (C) 2005 American Institute of Physics.