ABSTRACT
More recently, designing molecules for nonlinear optical (NLO), special bent-core molecules have been synthesized. Strong electron-withdrawing groups such as cyanocinnamate or nitro groups and an electron-donating group were introduced. Unlike rod-shaped molecular systems, molecular hyperpolarizability along the bent axis does not average out to zero because of polar packing. Second-order NLO effect is possible only in systems with no inversion symmetry under the electric dipole (ED) approximation. That is why second harmonic generation (SHG) has been successfully employed to examine polar structures in liquid crystals. Thus, the chiral nature of chiral domains spontaneously segregated from achiral bent-core molecules was clearly demonstrated using the chiral NLO effect. Bent-core mesogens provided with an exceptional system showing large chiral NLO effects.
