Third-order optical nonlinearities of composites in waveguide geometry

Results of degenerate four-wave mixing experiments in planar waveguides of gelatin doped with small gold particles are presented. The nonlinear response of the composite is examined at various wavelengths and doping levels. Conjugate reflectivities near 1% were observed for interaction lengths of a few millimeters and volume ratios of gold to gelatin in the 10/sup -6/ range. The frequency response of the reflectivity is analyzed through effective medium theory. Propagation losses must be included to properly explain the spectra.<
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