Generation of 532 nm laser radiation and phase matching properties of organic nonlinear optical material

Organic nonlinear optical single crystal of l-asparagine-l-tartaric acid (LAsT) was grown by slow evaporation technique at room temperature. The grown crystal was confirmed by single crystal X-ray diffraction and FT-IR studies. The direct band gap energy was found to be 5.4 eV. The SHG efficiency of the sample is 3 times higher than that of KDP crystal. The laser damage threshold of the grown crystal was 5.7 GW/cm2. The grown crystal was thermally stable up to 141 °C. Low dielectric constant at higher frequency was found by dielectric measurements. The activation energy was calculated from Arrhenius relation and it was found to be 0.088 eV. Negative photoconducting nature was obtained by photoconductivity measurements.