INTENSITY-DEPENDENT OPTICAL-ABSORPTION OF COLLOIDAL SOLUTIONS OF GOLDNANOPARTICLES

Intensity-dependent absorption measurements for determining the non-li near optical susceptibility of aqueous colloidal solutions of gold nan oparticles are presented. The diameters of the gold particles ranged f rom 50 to 400 Angstrom. Measurements were performed in the vicinity of the surface plasmon resonance frequency and the resonantly enhanced s usceptibility was found to be of the order of 5.10(-16)m(2)V(-2). This is attributed to a change in the Fermi-Dirac distribution of electron s about the Fermi level and is caused by an increase in their temperat ure due to absorption of resonant photons. The intensity dependence of the absorption showed that the system can be described as inhomogeneo usly broadened.