David J. Bergman[1], and David G. Stroud[1], [1] Department of Physics, The Ohio State University, Columbus, Ohio 43210; [2] School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Israel

Electrical and optical properties of weaklynonlinear composite media are reviewed. A simple perturbation theory can account for many properties, including enhancement of macroscopic nonlinear response near a quasi-static resonance of a metal/dielectric mixture. However, to describe properties like intrinsic optical bistability, a more elaborate approach is used. Approximations and tools are described for analyzing the properties of composites with generic microstructures, but some solvable microstructures are treated in greater detail, exploiting the existence of closed form expressions for the macroscopic response. The self-consistent effective-medium approximation for the weakly nonlinear response of composites is shown to be problematic, but its detailed analysis indicates how an improved self-consistent approximation scheme might be developed in the future.