DEVELOPMENT OF THE NONLINEAR-OPTICAL CRYSTAL CSTIOASO4 .2. CRYSTAL-GROWTH AND CHARACTERIZATION

We report here the crystal growth and characterization of the new nonlinear optical crystal CsTiOAsO4 (CTA). We have studied the Cs2O-TiO2-As2O5 ternary and identified the phase field within which orthorhombic CTA can be crystallized. Large inclusion-free single crystals measuring up to 30x20x25 mm3 can be readily grown using the Cs5As3O10 self-flux. As-grown CTA crystals have the same crystal facets as KTP, although they tend to be multidomain. We present here two techniques for removing these domains: by trivalent oxide dopings and by ferroelectric poling. The refractive indices, nonlinear optical coefficients, electro-optic coefficients and dielectric properties of single domain CTA crystals are reported. Compared to the crystal KTiOPO4, the smaller birefringence of CTA makes it particularly suitable for frequency doubling fundamental wavelengths between 1.3 and 1.5 mum. Our results suggest that CTA should find practical applications in electrooptic and in frequency conversion applications, such as optical parametric oscillators and compact diode-pumped solid state lasers.