Two-photon and one-photon resonant third-order nonlinear optical properties of π-conjugated polymers

Third-order nonlinear optical properties of a number of polymers with π-electron conjugated structures have been investigated. For several polymers large negative refractive nonlinearities measured at 800 nm are accompanied by large two-photon absorption coefficients. Very strong nonlinear effects can be achieved in polymers showing linear absorption and absorption saturation effects at 800 nm, the examples of which are polyaniline (salt form) and poly(indenofluorenone).