The temperature dependence of Nd3+ doped solid-state lasers

The temperature-dependent performance for long-pulse and Q-switched Nd³⁺ doped solid-state lasers are analyzed. Over a wide temperature range, it is shown that the output energy for the long-pulse laser decreases with increasing temperature as does that of the actively Q-switched laser when pumped to the same level of inversion at all temperatures. Conversely, when such lasers are pumped to the amplified spontaneous emission limit at each temperature or when the laser is passively Q-switched, the output energy increases with temperature. These temperature dependencies are analytically predicted and are compared to experimental results collected on various Nd:YAG and Cr:Nd:GSGG laser systems. The laser performance data and the model developed are shown to be in close agreement when using values for the stimulated-emission cross section and its temperature derivative obtained in separate spectroscopic measurements.