Enhancement of optical effects in zero-reflection metal slabs based on light-tunneling mechanism in metamaterials

Metals have many extraordinary optical properties. However, thick metals are nice mirrors, which prevent light penetrating deep into them. Since the skin depth is very thin, most optical properties of bulk metals are unavailable. In this paper, we review the way of reducing reflections in thick metal slabs by coating dielectric photonic crystals, based on the light-tunneling mechanism in metamaterials. Owing to the boost of local fields in the metals, many optical effects such as nonlinear effects, optical extinction (absorption) and optical rotation are greatly enhanced in these simple structures. The enhancement of optical effects in thick metals may be very useful in some optical devices including optical switches and diodes, absorbers, insulators and so on.