Efficient second-harmonic generation in a resonator

The process of second-harmonic generation in a lithium metaniobate crystal placed inside the resonator of a Q-switched laser is considered. A method is suggested for calculating the optimal second-harmonic generation conditions in a laser with a nonlinear crystal inside the resonator. Some features of the optimal nonlinear coupling are considered and changes in the duration of second-harmonic pulses are discussed. Some conditions of the operation of a laser in accordance with the suggested method are calculated and are shown to be in satisfactory agreement with the experimental results.