Third-Order Optical Nonlinearities in the Poly(2-Chloro-1,4-Phenylene Vinylene) Thin Film

A new polymer thin film, ploy (2-chloro-1,4-phenylene vinylene) (ClPPV), with high environmental and thermal stability, high optical damage threshold, and good film quality, was successfully prepared by the “precursor-route” method. Its third-order optical nonlinearities were measured by picosecond forward three-dimensional degenerate four-wave mixing technique. In the near resonance region (532nm), the measured third-order nonlinear optical coefficients x⁽³⁾_zzzz and x⁽³⁾_yzzy are 9.1 x 10^-l0 and 7.2 x 10^-11 esu, respectively, and its response time is quite fast, estimated to be less than picosecond. The Kerr effect, which arises from the distortion of the large quasi-one-dimensional π-conjugated electronic charge distribution of ClPPV, is the main reason for generating third-order optical nonlinearities.