Nonlinear optical response of poly(p-phenylenevinylene): Role of photogenerated gap states

Abstract

Third order nonlinear optical properties of Poly(p-phenylenevinylene) have been investigated at 532 nm using degenerate four wave mixing and Z-scan techniques. Intensity dependent absorption has been attributed to photogenerated gap states arising from one-photon pi-pi* transition, and the coefficient of nonlinear absorption has been estimated. The observed intensity dependence of the degenerate four wave mixing signal has been explained using four-level model involving gap state transitions.