Investigation on the growth and properties of non linear optical crystals

Abstract

Crystal growth and characterization is a vital and fundamental part in the field of surface physics, crystallography, material science and engineering. The importance of NLO phenomena leads to the development of nonlinear optical materials. To date these materials are utilized in information processing, optical switching, frequency conversion, telecommunication and optotechnology. Hence the search and growth of new nonlinear optical materials having novel properties is an indispensable area of research. Single crystal X-ray diffraction studies shows thiourea cadmium-zinc sulphate belongs to triclinic system. The crystalline nature of the grown crystal was confirmed by powder X-ray diffraction and the diffraction peaks were indexed for the lattice parameters a = 8.7385 Å, b = 9.0547 Å, c= 9.7478 Å. The surface morphology reveals that for each face, their parallel friedel planes also present in the grown crystal. Thermal studies show that the material is stable up to 422 K. The laser second harmonic generation intensity of 2-Aminopyridinium maleate crystal was found to be 1.5 times higher than that of the reference KDP sample. It was found that the crystal belongs to monoclinic system. Differential thermal and thermo gravimetric analysis reveals that the crystal is stable up to 437.8 K. From the hardness measurement, the crystal is mechanically stable up to 100 g. The SHG efficiency of tris thiourea glycine was found to be 0.8 times that of KDP crystal. The second harmonic generation intensity of 2-Aminopyridinium benzoate crystal was found to be 1.8 times higher than that of KDP reference material. An organic nonlinear optical material Benzoyl Glycine (BG) was grown in a mixed solvent of N, N-Dimethyl Formamide and water by slow cooling technique. It was found that the crystal belongs to orthorhombic system and crystallizes in the non centro symmetric space group P212121. UVVis- NIR absorption spectrum shows lower cut off at 340 nm.