Investigation of thermo-optical effects in a nonlinear ZnGeP

\nThis work is dedicated to investigating the thermo-optical effects in a nonlinear ZnGeP2 crystal during parametric generation. The stable regime of the laser resonator was determined. It was found that for a resonator length of 43 mm, a stable regime was observed for all focal lengths of the thermal lens induced in the crystal. However, increasing the resonator length to 183 mm, the stability zone of the cavity no longer extends to the entire range of focal lengths of the induced thermal lens. Thus, the resonator becomes unstable for focal lengths of the induced thermal lens f ≤ 150 mm, which leads to high intracavity losses and is an undesirable operating mode of the cavity. Therefore, the experimental work has shown that when creating systems based on parametric generators with ZnGeP2 crystals, it is essential to consider the effect of the induced thermal lens and perform calculations of the cavity stability.\n