NONLINEAR-OPTICAL PROPERTIES OF SILVER SOLS PREPARED BY PHOTOREDUCTION METHOD

The third-order nonlinear susceptibility (chi((3))) Of silver sol prep ared by a photochemical method was measured by the degenerate four-wav e mixing method. The chi((3)) Of the silver sol of brown-green color w as larger than that of yellow-brown color. The photo-induced aggregati on of silver particles affects the chi((3)) Of the sol. It has been fo und that the chi((3)) of the silver sol is proportional to the intensi ty of surface-enhanced raman scattering from carboxylate ions adsorbed on the silver particle. The increase of chi((3)) by the enhanced loca l electric field due to surface plasmon resonance is proposed.