Interference effects in microchip laser with intracavity frequency doubling

The temperature dependence of output power of microchip laser with intracavity frequency doubling is investigated, where oscillations in the output power are observed. Similar oscillations are observed in the temperature tuning of single pass second harmonic generation in plane parallel nonlinear crystal. It is supposed that in both two cases the oscillations have the same origin. Single pass second harmonic generation is investigated experimentally and theoretically, and it is shown that oscillations are due to multiple beam interference in the nonlinear crystal. Results of the experiments and calculations are presented.