Third Order Susceptibility of Platinum Sulfide Sol

The optical properties of a suspension of small metal particles in a transparent medium can differ strikingly from those of the same metal in bulk form. New materials with large values of X3, the third order nonlinear susceptibility tensor are needed. Recent trends in nonlinear optics have centered on processes involving X3. One method of determining X3 involves the measurement of the optical phase conjugate signal generated by the sample. Experimentally this is determined using degenerate four-wave mixing DFWM. Pure sulfur sol was prepared by dissolving the solid sulfur in hydrazine, followed by addition of distilled water with vigorous stirring. The sulfur sol thus produced was sealed and stored in the dark. Platinum sols were produced by reduction of platinum chloride with 1 sodium citrate. Both solutions were mixed and heated for 30 minutes at 80 deg C. Finally, both the sulfur sol and platinum sol were mixed in equal parts and heated while stirring at 80 deg C for approximately 15 minutes until no further color change.