Growth, non-linear optical, photoconductivity and dielectric characterization of pure and EDTA doped tris-glycine zinc chloride single crystals for LiDAR

Non-linear optical crystals which are used as frequency converters to access various spectral ranges like visible or UV are key components of (Light Detection and ranging) LiDAR systems. For this purpose promising non-linear optical crystals like tris-glycine zinc chloride (TGZC) a nonlinear optical material, with the additive Ethylenediaminetetraacetic acid (EDTA) is grown successfully by slow cooling technique. In order to improve the device characteristics of TGZC crystals, organic dopant EDTA were incorporated into the parent crystals. Observation of the crystal growth, behavior and measurement of growth kinetics revealed a strong dependence of growth rate on the additive. The slight change in unit-cell parameters of the doped compound from the pure TGZC were confirmed by single crystal X-ray diffraction analysis. The presence of functional groups is estimated qualitatively by FTIR analysis. The UV-vis spectrum shows a cut-off wavelength less than 300 nm. The photocurrent of both pure and doped crystals is more than that of the dark current. Microhardness studies carried out using Leitz Weitzler hardness tester at room temperature showed an increase due to doping. The dielectric loss is low at high frequency and this behavior is of vital importance for NLO applications. In this paper, an attempt has been made on the growth and characterization of nonlinear optical crystal and theoretical aspects of single crystals as frequency convertors in Atmospheric Remote Sensing is discussed.