Optical nonlinearity enhancement in heterostructures with thick metallic film and truncated photonic crystals.

It is hard to use bulk metals with high nonlinear susceptibilities since they are nearly opaque. Metal-dielectric photonic crystals can be transparent, but the electric field at each metal layer is still low. We theoretically studied the nonlinear response of heterostructures composed of truncated all-dielectric photonic crystals and thick metallic films. Because of the localized interface modes, both transmittance and the electric field in the metal are enhanced greatly. Compared to metal-dielectric photonic crystals, the critical intensity of threshold for bistability in the heterostructures with the same thickness of metal can be reduced by nearly 2 orders of magnitude.