Evaluation of the energy transfer rate for the Yb3+:Pr3+ system in lead fluoroindogallate glasses

In this article, we report on spectroscopic studies of Pr3+:Yb3+ codoped lead fluoroindogallate glasses. By pumping with a diode laser in 0.98 mu m, it was verified that the intensity of infrared luminescence at 1.3 mu m of Pr3+ ((1)G(4)-->H-3(5)) is highly increased (approximately 40 times) by the presence of Yb3+. Anti-Stokes luminescence (upconversion), which represents a loss mechanism for the infrared emission, was also observed. These features were attributed to an efficient energy transfer process from Yb3+ to Pr3+. Calculation of the energy transfer constant (Cs-a) and energy transfer rate (Ps-a) showed that the process from Yb3+ to Pr3+ is nearly one order of magnitude greater than in the opposite direction. The energy transfer efficiency obtained was about 92%. The best molar ratio Pr3+:Yb3+ is 1:4 for both infrared and upconverted luminescence signals. (C) 1999 American Institute of Physics. [S0021-8979(99)06517-2].