Synthesis, growth and characterization of semi-organic nonlinear optical bis thiourea antimony tri bromide (BTAB) single crystals

A novel nonlinear optical metal-organic, Bis thiourea antimony tri bromide (BTAB) single crystal was grown from aqueous solution by slow cooling technique. The grown crystals have been characterized by different techniques to study the structural, thermal, mechanical, linear and nonlinear optical properties. The powder SHG efficiency was found to be 2.5 times higher than that of the KDP crystal. BTAB is a biaxial and optically positive crystal. The birefringence value of BTAB crystal was found to be 0.112 at the wavelength of 550 nm for a sample thickness of 0.11 mm. The BTAB crystal has refractive indices values of n(alpha)=1.539, n(beta)=1.559 and n(gamma)=1.967. BTAB crystallizes in orthorhombic system and the complex formation is established by metal-sulfur bond. BTAB has good optical transmission in the entire visible region, so that it is found to be potential material for nonlinear frequency conversion. (C) 2009 Elsevier B.V. All rights reserved.