Study of the local inhomogeneities Δχ (2) of the quadratic nonlinear susceptibility tensor in KTiOPO 4 crystals

The local inhomogeneities Δχ(2) of the quadratic nonlinear susceptibility tensor in the KTiOPO4 (KTP) crystal have been investigated. A method for visualizing the nonlinear-optical inhomogeneities is proposed that makes it possible to observe monodomain regions in the crystal. The method is based on an analysis of the interference pattern of the second harmonic, generated in KTiOPO4 by a strongly divergent laser beam. A connection is established between the nonlinear-optical homogeneity of the growth pyramids of the {201} and (100) faces and their growth mechanisms.