Two-Crystal Design and Numerical Simulations for High-Average-Power Second-Harmonic Generation

Temperature-insensitive phase-matching of second-harmonic generation (SHG) can be realized using two nonlinear crystals with opposite signs of the temperature derivation of phase mismatch. The design procedure for optimizing crystal lengths is presented, and full numerical simulations for the SHG process, based on realistic crystals, are performed at a typical high-power-laser wavelength of ～1 μm. It is suggested that the proposed two-crystal design can support high efficiency (60–70%) of SHG in the high-average power regime of a kilowatt.