Measurement of the third-order hyperpolarizability of platinum poly-ynes.

We present the measurements of the third-order polarizability (gamma) of several platinum poly-ynes obtained using picosecond laser pulses. The real part of gamma was measured using the optical Kerr effect with a 1.064-microm pump and a 0.532-microm probe. The imaginary part was evaluated from the two-photon absorption coefficient determined at 0.532 microm. The platinum poly-ynes had low absorption in the visible and the near-infrared wavelengths.