A new view on the temperature insensitivity of intracavity SHG configuration

Experimental results indicate that there is a distinct difference between the temperature tuning curves obtained with intracavity second harmonic generation (Intra-SHG) and extracavity SHG (Extra-SHG) configuration. By introducing the nonlinear SHG loss with the phase mismatch taken into consideration, the rate equations are established to describe the Intra-SHG laser performance. As for the widely used SHG crystal, KTP and LBO, theoretically calculated variation trends of the temperature insensitivity are in agreement with that obtained experimentally. The corresponding explanations have also been given in this paper. Our results may provide a new view on the temperature insensitivity of Intra-SHG configuration. The method employed in our study can be extended to other nonlinear crystals and intracavity nonlinear frequency conversions.