Growth of organic nonlinear optical (NLO) ammonium D,L-tartrate (AMT) single crystal by conventional and unidirectional method and its characterization

Abstract

High-quality, transparent uniaxial ammonium D,L-tartrate (AMT) single crystal having dimension of 15 mm diameter and 60 mm length was grown by Sankaranarayanan–Ramasamy (SR) method with a growth rate of 1 mm per day. Single-crystal X-ray diffraction was carried out to confirm the AMT crystals. The presence of functional groups of crystallized AMT molecules were identified by FTIR spectral analysis. The dislocation density of the AMT crystals grown by slow evaporation solution technique (SEST) and SR method were characterized using chemical etching analysis. A comparative laser damage threshold analysis was made on the AMT crystals grown by conventional and SR method which shows that the crystal grown by SR method has higher damage threshold. The SR method grown AMT crystal has higher microhardness and also higher optical transmittance compared to conventional method grown crystal. The thermal properties of the SEST and SR method grown AMT crystals were measured by photoacoustic spectrum analysis. The second harmonic generation efficiency of AMT was determined using the powder Kurtz–Perry technique.