Physics and Chemistry of Crystalline Lithium Niobate (1990)

Introduction. Physico-chemical properties of lithium metaniobate: Phase diagram for the Li^O2-0-Nb^O 2O^O5 system. Crystal structure of lithium metaniobate. Crystal-chemical features of metaniobates of alkali metals. Phase formation in LN Crystals. Methods of obtaining single crystals of lithium niobate. Peculiarities of growth of LN single crystals. Synthesis of the charge and preparation of the melt. Choice of the optimum conditions for growth. Growth conditions for LN crystals of a constant radius. High-temperature annealing and formation of single-domains in crystal. The Stepanov technique. Electric phenomena arising in crystallization of LN. Defect structure of single-crystal lithium niobate: Morphology and macro-defects. Point defects in LN. Formation of F centres in LN crystals. Twinning in LN crystals. The domain structure of lithium metaniobate crystals: Ferroelectric domains in lithium metaniobate. Selective etching of LN crystals. Growth domain structure. Formation of a stationary domain structure. Depolarisation mechanisms of lithium metaniobate crystals. The influence of temperature gradients on domain formation in the process of crystal growth and annealing. The effect of annealing on the near-surface domain structure. The regular domain structure in LN crystals. Electrical properties of lithium metaniobate: Electric conductivity. Dielectric properties. Thermal diffusion in lithium niobate crystals. Relaxation phenomena in lithium niobate crystals. Electric fields in lithium niobate crystals. Electric effect and relaxation polarization of lithium niobate. Thermionic emission of lithium niobate single crystals. Effective ion charges and spontaneous electric moment of lithium niobate. Optical and electro-optical properties of lithium metaniobate single crystals. Optical properties of lithium metaniobate. Electro-optical effect in dielectric crystals. Phenomenological theory of the electro-optical effect. Establishment of electro-optic coefficients. Specific features of lithium niobate crystals applications in electro-optical devices. Nonlinear optical properties of lithium niobate: Elements of nonlinear optics. Methods used to establish nonlinear coefficients. Relationship of birefringence and phase-matching temperature to lithium niobate crystal composition. Criteria for nonlinear-optical quality of crystals. Enhancement of SHG in lithium niobate crystals with periodic laminar ferroelectric domains. Photoelectrical and photo-refractive properties: Model representations of the photo-refractive effect. Occurrence of optical distortion in lithium niobate crystals exposed to cw laser radiation. Occurence of optical distortion in lithium niobate exposed to pulsed laser radiation. Laser-induced physical effects in lithium niobate. Photo-induced distortion of the crystal structure in lithium niobate. Optical inhomogeneity of crystals and methods of its investigation. Nature of optical inhomogeneity. Electrically induced optical inhomogeneity of crystals. Doping and heat treatment effects on crystal optical inhomogeneity. Methods used to observe optical inhomogeneities in lithium niobate crystals. Conclusions. References. Index.