The Investigation of Third-Order Hyperpolarizabilities and Susceptibilities of Push-Pull Azobenzene Polymers

To estimate the potential for third-order nonlinear optical (NLO) properties of the title azobenzene polymers, the one-photon absorption (OPA) and two-photon absorption (TPA) characterizations have been determined by configuration interaction (CI) and time-dependent Hartree-Fock (TDHF) methods, respectively. The nonlinear absorption parameters (beta) and third-order susceptibilities (chi((3))) have been measured by performing the Z-scan measurements. According to the ab-initio computation results, the investigated compounds exhibit averaged (isotropic) second hyperpolarizabilities (<gamma >) with non-zero values, implying microscopic third-order optical nonlinearity. Our computed results on TPA cross-sections (delta(omega)), third-order hyperpolarizability and susceptibility values are in accord with the experimental observations of the examined molecules.