Temperature dependence of Nd(super 3 +)<->Yb(super 3+) energy transfer in the YAl3(BO3)(sub 4) nonlinear laser crystal

The temperature dependence of the Nd(super 3 +)Yb(super 3+) energy transfer rate in the YAL3(BO3)4 nonlinear laser crystal is investigated from the analysis of fluorescence decay curves recorded in the 10-600 K range. The populations of both Nd(super 3+) and Yb(super 3+) metastable states achieved after continuous-wave Nd(super 3+) excitation is calculated and measured and result is explained in terms of the thermal behavior of both forward and back transfer rates.