Analysis and direct calculation of the energy migration interaction parameter in high concentration Nd3+ doped YAG laser crystal

The energy migration interaction parameter CDD in high concentration Nd3+ doped YAG laser crystal was estimated using the Yokota-Tanimoto (Y-T) model and the spectral overlap model (SOM) of Kushida, respectively. Firstly, the experimental luminescence decay curves of 4F3/2 state of Nd3+ ions in YAG laser crystal at room temperature for 2.0at.% and 3.0at.% Nd3+ concentrations reported by Mao were fitted successfully using the Y-T model, and the parameter CDD was obtained to be 1.50×10-39 cm6/s. Secondly, the parameter CDD was directly calculated using the spectral overlap model (SOM) of Kushida; CDD was calculated to be 2.73×10-39 cm6/s. By comparing the energy migration interaction parameter CDD with the energy transfer interaction parameter CDA (1.794×10-40 cm6/s), it was concluded that the energy migration rate between Nd3+ ions in YAG laser crystal was about 11 times larger than the energy transfer rate, and that energy migration played a very important role in high concentration Nd3+ -doped YAG laser crystal.