On the optical quality of KTP crystals for nonlinear optical and electro-optic applications

Correlation between conditions of the top-seeded solution growth (TSSG) of potassium titanyl phosphate (KTP) crystals from self-fluxes and their optical uniformity has been studied with respect to the crystal morphology, variation of stoichiometry and formation of point defects. It has been shown that growth with pulling on X-oriented seeds yields single sector crystals exhibiting the ideal transverse optical uniformity necessary for the design of eye-safe optical parametric oscillations (OPO) and electro-optic elements based on the KTP crystals. Variation of stoichiometry has been studied using powders synthesized by solid state reaction and measuring the Curie temperatures of samples synthesized from batches with different starting compositions. Growth from self-fluxes at lower temperatures is found to reduce the concentration of potassium vacancies and their gradients and thus to suppress the detrimental gray-tracking phenomenon during frequency doubling of the 1064 nm Nd:YAG laser radiation into the green. (C) 2001 Elsevier Science B.V. All rights reserved.