Numerical study of effective optical nonlinear properties in composites with anomalous distribution

We investigate the nonlinear optical response of random composites consisting of nonlinear conductors and linear conductors with an anomalous distribution. Random resistor-capacitor networks are used to simulate our model, in which the nonlinear component with the fraction p is taken as i=g1ν+χ1 vertical ν vertical bar2v and the linear component with the fraction 1-p obeys an anomalous distribution h(g2)∼g2-α, where 0<g2<1. We find that the distribution exponent α plays an important role in the effective linear and nonlinear optical response. As α decreases, the enhancement of optical nonlinear χe can be achieved. Moreover, the effective nonlinear optical response exhibits a sharp peak at a moderate volume fraction, dependent on α. The effective medium approximation is found to be in good agreement with linear response of numerical simulation, and describes nonlinear response of our numerical results qualitatively