Z-SCAN STUDIES OF THE NONLINEAR OPTICAL PROPERTIES OF GOLD AQUEOUS COLLOID PREPARED BY THE CHEMICAL REACTION METHOD

Nonlinear optical properties of gold aqueous colloid obtained with chemical reaction method are investigated using Z-scan technique with 38 ps pulses. Experimental results indicate that the colloid exhibits large nonlinear refraction and nonlinear absorption under the excitation of ps 532 nm pulses, while it presents large two photon absorption under ps 1064 nm pulses excitation. Meanwhile, the fluorescence emission spectrum of gold aqueous colloid is recorded under the excitation of 350 nm, and two fluorescence peaks are observed at 454 nm and 704 nm. Moreover, the average fluorescence lifetime of colloid is estimated to be 1.33 ns.