Unidirectional growth of non-linear optical triglycine calcium dibromide single crystal by a Sankaranaryanan–Ramasamy method

Abstract

Single crystals oriented along prerequisite direction are very important in terms of reducing loss of material and cost during nonlinear optical device fabrication. A transparent uniaxial triglycine calcium dibromide single crystal having dimension of 10mm diameter and 126mm length was grown by a Sankaranarayanan–Ramasamy (SR) method with a growth rate of 2mm per day. From the optical transmittance study it is observed that the crystal grown by the SR method has 10% higher transmittance compared to a conventional method grown crystals. High intense luminescence at 368nm for the SR method grown crystal is observed from the photoluminescence study. The etch pit density of the conventional and SR method grown crystal is found as 4.5×103cm−2 and 3.5×103cm−2 respectively. The average laser damage threshold obtained on the conventional method grown crystal was 3.74Gw/cm2 whereas a high damage threshold of 4.78Gw/cm2 was obtained for the SR grown crystal. The crystal grown by the SR method shows high mechanical strength and good laser damage stability with low dislocation density which make it suitable for the SHG device fabrication.