Optimal Vector Phase Matching for Second Harmonic Generation in Orthorhombic Non-Linear Optical Crystals

Optimal geometries of vector phase matching are determined for the second harmonic generation in biaxial non-linear optical crystals of orthorhombic symmetry- CBO, LRB4, LBO, KB5, KNbO3, KTA, KTP. The directions of wave vectors ensuring the highest possible efficiency of the second harmonic generation are defined by the extreme surface method. It is shown, that the increase of the second harmonic generation efficiency (tens to hundreds per cent) provided by the realization of vector phasematching conditions compared to the case of the scalar ones takes place for CBO, LRB4, KB5, KNbO3, KTA and KTP crystals.