Investigation on growth, structural, mechanical, linear and nonlinear optical properties of DiLithium Fumarate TetraHydrate single crystal

In this work reports on the growth and characterization of semiorganic NLO single crystal of DiLithium Fumarate TetraHydrate (DLFTH) using a slow evaporation technique. The crystal structure was an orthorhombic crystal system with the centrosymmetric space group Pbcn, as demonstrated by single crystal X-ray diffraction (SCXRD) investigations. The UV-Vis-NIR spectrum is used to derive optical parameters, such as the lower cut off wavelength (277 nm) and optical energy band gap Eg = 4.98 eV. DLFTH crystals belongs to hard material category using Vickers microhardness test. From NLO studies, the nonlinear optical parameters were studied, such as the nonlinear refractive index (n(2)), absorption coefficient (beta) and third order NLO susceptibility (chi(3)). The crystal has the properties of saturable absorption and self-defocusing nature. Third order NLO susceptibility (chi(3)) were found to be 4.14384 x 10(-10) esu. The higher chi(3) number is due to the presence of hydrogen bonds between C-H-O and O-H-O atoms. Therefore, we confirm that it's applicability for optical device applications.