Growth, mechanical, dielectric, thermal and optical studies of a nonlinear optical crystal: l-Histidinium dipicrate dihydrate

Abstract

Nonlinear optical single crystals of l-histidinium dipicrate dihydrate (LHDPDH) were grown by slow evaporation solution growth technique at room temperature. The microstructure and growth features were analysed by chemical etching. The grown crystal was subjected to X-ray diffraction analysis to confirm its purity and crystal structure. Mechanical behaviour of the grown crystal was analysed by Vicker's microhardness test. The stiffness constant was evaluated for various loads. The dielectric behaviour was investigated at different frequencies and temperatures. AC conductivity and activation energy were determined. Electronic properties, such as valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability were calculated. Thermal analysis confirmed the association of two water molecules in the crystal lattice of LHDPDH and revealed the thermal stability of the crystal. Photoconductivity study reveals that LHDPDH exhibits positive photoconductivity. The optical transmission window and optical band gap of the crystal were found by UV–vis–NIR studies. Second harmonic generation efficiency was found to be 2.5 times that of the standard KDP crystal. The laser damage threshold for the grown crystal was measured using Nd:YAG laser.