A comparative study of the energy migration and energy transfer in highly doped Nd:YAG single crystal

The donor-donor (D-D) energy migration interaction parameter COD in high-concentration Nd(3+)-doped YAG laser crystal is estimated, for the first time, by using the Yokota-Tanimoto (Y-T) model and the spectral overlap model (SOM) of Kushida. Firstly, the experimental luminescence decay curves of (4)F(3/2) state of Nd(3+) ions in YAG laser crystal at room temperature for 2.0 and 3.0 at% Nd(3+) concentrations reported by Mao are fitted successfully by using the Y-T model and the parameter Coo is obtained to be 1.50 x 10(-39) cm(6)/s. Secondly, the parameter C(DD) is also directly calculated by using the SOM of Kushida: C(DD) is calculated to be 2.73 x 10(-39) cm(6)/s. By comparing the energy migration interaction parameter C(DD) and the donor-acceptor (D-A) energy transfer interaction parameter C(DA) (1.794 x 10(-40) cm(6)/s), it is concluded that energy migration rate between Nd(3+) ions in YAG laser crystal was about 11 times larger than energy transfer rate, and that energy migration would play a very important role in high-concentration Nd(3+)-doped YAG laser crystal. (C) 2008 Elsevier B.V. All rights reserved.