Optical nonlinearity enhancement of a periodic array of metal elliptical cylinders

We investigate the effect of geometric anisotropy on optical nonlinearity enhancement for composites with metal elliptical cylinders periodically in an insulation host. Based on the Stroud–Hui relation and a series expression of the space-dependent electric field in periodic composites, the frequency dependences of the effective nonlinear susceptibility are calculated. The results show that for the metal-insulator composites, the nonlinearity enhancement increases almost to its maximum when a structure with layers of fluctuating thicknesses forms, and exhibits a local minimum at the percolation threshold. We also conclude that the nonlinearity enhancement reaches its maximum when composites with elliptical inclusions are transformed into Boyd–Sipe-type layered composites.