Measurements of the third-order nonlinearity of a soluble polycarbazolyldiacetylene by picosecond< i> Z-scan at 1064 and 1500 nm

The complex ?(3) of toluene solutions of polydiacetylene, polyDCHD-HS, was measured by using Z-scan at ?=1064 and 1500 nm and with picosecond pulses in order to estimate the potentials of this polymer for application to all-optical switching devices. The values of the real part of molecular hyperpolarizability ? were -2.3×10-47 and -3×10-47 m5/V2 at 1064 and 1500 nm, respectively. The nonlinear absorption could be better modeled with a three-photon process at both the wavelengths instead of the expected two-photon mechanism.