Numerical simulation of stable second harmonic generation using phase mismatching

A method is put forward to stabilize the second harmonic generation using phase mismatching. BBO type Ⅰ phase matching SHG course and KTP type Ⅱ phase matching course were simulated. Simulation results show that both type Ⅰ and type Ⅱ phase matching can get 2ω stable output by letting laser deviate from phase matching angle. With the increasement of the deviating angle, the length of the nonlinear crystal required to get stable 2ω output reduces, the fluctuation and the conversion efficiency of second harmonic generation output when the stable 2ω output is obtained become smaller. Compared with KTP type Ⅱ phase matching, BBO type Ⅰ phase matching is more sensitive to deviating angle and the conversion efficiency is smaller.