EXPERIMENTAL-OBSERVATION OF SURFACE-ENHANCED COHERENT ANTI-STOKES-RAMAN SCATTERING

Surface-enhanced coherent anti-Stokes Raman scattering has been observ ed on colloidal silver surface from benzene, the mixture of benzene an d N,N-dimethylformamide, toluene, and chlorobenzene. Silver colloids w hich were prepared in organic solvent N,N-dimethylformamide were used as an enhancement medium. The scattered CARS light was collected at ri ght angles with respect to the exciting pump and Stokes laser beams. I t was found that not only is the CARS signal significantly enhanced bu t the signal-to-noise ratio is also improved after addition of the sil ver sol. An excitation profile study shows a maximum enhancement for t he benzene-silver sol system located at about 500 nm pump laser wavele ngth. This is in good accord with the surface plasmon resonance of the system.