Since the invention of the first laser 30 years ago, the frequency conversion of laser radiation in nonlinear optical crystals has become an important technique widely used in quantum electronies and laser physies for solving various scientific and engineering problems. The fundamental physics of three-wave light interactions in nonlinear optical crystals is now largely understood. This has enabled the production of the various harmonie generators, sum and difference frequency generators, and parametrie oscillators based on nonlinear crystals that are now commercially available. At the same time, scientists continue an active search for novel high-efficiency optical materials. Therefore, in our opinion, there is a great need for a handbook of nonlinear optical crystals, intended for specialists and practitioners with an engineering background. This book contains a complete description of the properties and applications of all nonlinear crystals reported in the literature up to the beginning of 1990. In addition, it contains the most important equations for calculating the main parameters (such as phase-matching direction, effective nonlinearity, and conversion efficiency) of nonlinear frequency converters. Dolgoprudnyi, Yerevan, V. G. Dmitriev Troitzk, USSR G. G. Gurzadyan D. N. Nikogosyan October 1990 Contents List of Abbreviations. XIII 1. Introduction . . . . 2. Optics of Nonlinear Crystals . . . . . . . . . . . . . 3 2.1 Three-Wave (Three-Frequency) Interactions . 3 2.2 Phase-Matching Conditions . . . . . . . . . . 4 2.3 Optics of Uni axial Crystals .......... . 6 2.4 Types of Phase Matching in Uniaxial Crystals ...... . 10 2.5 Calculation of Phase-Matching Angles in Uniaxial Crystals ..