Optical bistability in nonlinear composite media

The mean-field approximation method is proposed to investigate the intrinsi c optical bistability in nonlinear composite media, which consists of nonli near metallic granules embedded in nonlinear dielectric host. The effect of nonlinear susceptibility on the bistable behavior is analyzed. It is found that nonlinear metallic granules and nonlinear host medium have different effects and the nonlinearity of metallic granules is more effective in mini mizing the threshould value of the bistable behavior. We also investigate t he effect of the shape factor of metallic granules on the threshold value.