Study of some amino acid based non-linear optical materials

Non-linear optical (NLO) single crystals of L-valine 1-valinium orthophosphate (LVP) and L-valine 1-valinium nitrate (LVN) were grown by slow evaporation solution growth method using water as the solvent at room temperature. Purity of the crystals was increased by the method of recrystallization. The cell parameters of LVP and LVN were determined using single crystal X-ray diffraction technique. The grown crystals were characterized by measuring their thermal, optical and mechanical properties by Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA), Powder Second Harmonic Generation (SHG) efficiency, FTIR, UV-VIS NIR, damage threshold and microhardness measurements. The dielectric constant and dielectric loss of the crystals have been studied as a function of frequency at room temperature. Our studies showed that L-valine inorganic acids emerged as most promising NLO materials having SHG efficiency, mechanical and thermal stability greater than other semi-organic NLO materials.