Theoretical analysis of the second-harmonic light power in a biaxial crystal

Theoretical analyses are presented on the critically phase-matched second-harmonic generation(SHG) in a biaxial crystal with the focused fundamental Gaussian beams.The dependence of the second-harmonic light power on the phase matching conditions,focused geometries,walk-off effects,and absorptions are discussed in detail.Expressions are presented for calculating the light power of the types I and II SHGs in the biaxial crystal,applied to optimize the blue light generation with the LiB3O5 crystal.A maximum conversion efficiency of around 37% is obtained with 798-nm laser power of 500 mW.