Radiatively and tunnel-coupled surface electromagnetic waves in metal — dielectric structures

The surface electromagnetic modes in five-layer metal — dielectric structures are investigated by a numerical computational method. The existence of two types of plasmon modes — radiatively and tunnel-coupled — is demonstrated. The mode type is determined by the specific geometry of the structure. The results of estimates of the effective refractive index of the plasmon leaky mode excited in an asymmetric three-layer metal — dielectric structure, are presented. The optical transparency effect, arising on excitation of the tunnel-coupled surface electromagnetic waves, is demonstrated experimentally.