Synthesis and study of the linear and nonlinear properties of N,N'-bis (2-hydroxybenzylidene) benzidine using Z-scan technique and quantum mechanical calculations

In this work, the linear and nonlinear optical properties of the Schiff base N,N'-bis(2-hydroxybenzylidene) benzidine (HBB) will be investigated by two methods, Z-scan technique and quantum mechanical calculations. For this purpose, first, the absorption spectrum of HBB compound in DMSO, DMF, CH3Cl is prepared and the effect of solvent polarity on their bandgap energy is investigated. The results show that the dissolved sample in DMSO has better nonlinear properties than other samples. Then, the nonlinear properties of the sample are calculated by the Z-scan technique. The values of the nonlinear refractive index, nonlinear absorption coefficient and third order susceptibility of the sample in DMSO solvent are 0.10810-10 cm2/W, 0.1436110-6 cm/W and 4.43710-9 esu respectively. Also, the quantum mechanical analysis will be used for calculating the dipole moment (), the dipole polarizability (), and also the second and third nonlinear molecular hyperpolarizabilities (β and γ). Both experimental and theoretical results show that the HBB has a high nonlinear potential and can be a good candidate for optical devices.