Crystal growth and optical characterization of an organic single crystal for frequency conversion applications

Abstract

Organic nonlinear optical 2-methylquinolinium L-malate single crystals have been grown by slow evaporation solution growth technique from a mixture of 2-methylqiunoline and L-malic acid in ethanol solution at ambient temperature. Single crystal X-ray diffraction analysis reveals that grown crystal in monoclinic system with non-centrosymmetric space group P21 and the lattice parameters are a = 7.35 Ǻ, b = 26.51 Ǻ, c = 10.83 Á, α = γ = 90° β = 102.95º and V = 2057.4 Ǻ3. UV-vis spectrum indicates that the crystal is transparent (75%) in the entire visible region with a cut-off wavelength of 437 nm and optical energy band gap Eg is found to be 2.71 eV. Microhardness measurement reveals the mechanical strength of the grown crystal. The photoluminescence spectrum shows the blue emission of the crystal. Laser damage threshold studies was carried out to ascertain the suitability of grown crystal for laser applications.The relative second harmonic generation efficiency of 2-methlquinolinium L-malate crystal was found to be two times greater than that of KDP.