Optical nonlinearity of nanocrystalline Au/ZnO compostite films

The third-order nonlinear optical susceptibilities, chi((3)), of composite films consisting of nanocrystalline Au and ZnO particles were investigated by use of a degenerate four-wave mixing scheme. The maximum value of chi((3)), measured at a laser wavelength of 532 nm and a pulse duration of 70 ps, was similar to2 x 10(-6)esu. Also, this chi((3)) value was achieved with small absorption (the surface-plasmon peak was at the 615-nm wavelength). Our composite materials showed no discernible degradation after they were subjected to irradiation for a total of 3 x 10(7) high-intensity pulses (24 Mw/cm(2), 70-ps pulse duration at 500 Hz) during 16 h of testing. (C) 2003 Optical Society of America.