Growth and applications of photorefractive potassium lithium tantalate niobate (KLTN)

This thesis describes the growth of potassium lithium tantalate niobate (KLTN) single crystal material and characterization of its physical and photorefractive properties. The band transport model is used to discuss the conventional photorefractive effect. The coupled mode formalism is introduced to obtain solutions for intensity - and phase coupling between two interfering beams, as well as diffraction off a dynamic index grating, for both the copropagating and counterpropagating experimental geometries and for arbitrary photorefractive phase, φ. The linear- and quadratic electro-optic effects are discussed. The top seeded solution growth method is reviewed. The design and construction of a crystal growth system is described. The growth procedures of KLTN are enumerated for several compositions and dopant types. Phase diagrams of the KLTN system are determined. Structural properties and material characteristics of the grown crystals are discussed. Electric field control of the photorefractive effect is demonstrated for paraelectric KLTN. A theory is developed to describe the diffraction of beams off photorefractive index gratings in paraelectric KLTN. The solutions of the coupled mode equations are used to develop methods of determining the photorefractive phase φ in a photorefractive material. These methods are experimentally demonstrated for several types of photorefractive material, including paraelectric KLTN. A new effect, the Zero External Field Photorefractive (ZEFPR) effect is studied, as well as the application of its unique zero phase (φ = 0) photorefractive theory; its origin is shown to be due to the creation of strain gratings under spatially periodic illumination. The ZEFPR gratings are shown to possess identically zero phase when no external electric field is applied. This property is employed in the implementation of various new linear phase-to-intensity transduction devices