The crystal-length and acceptance parameters of SFG with biaxial crystals

The crystal-length and acceptance parameters of biaxial crystals KTP and LBO used to generate 589nm radiation by means of sum frequency generation(SFG) of 1064nm and 1319nm lasers is analyzed.According to the nonlinear wave-coupling equation of SFG,the exact solutions of low and high power conversion are derived and validated in SFG.On the basis of the solutions,the relationship between power density and crystal-length is given.Acceptance parameters of biaxial crystals are derived and validated from phase matching condition of SFG by means of Taylor expansion.The properties of non-critical phase matching(NCPM) is put forward.It can be seen that sum-frequency conversion efficiency could be increased with appropriate crystal-length,type-ⅠLBO and type-ⅡA KTP are much better and NCPM can be attained for LBO at 32.84℃.