Sommerfeld Pole or Brewster Zero?: Zenneck wave or surface plasmon?

Abstract

The surface waves that may exist at a planar interface between a lossless dielectric and a conventional or plasmonic medium are investigated. It is shown that these surface waves are pole waves associated with the pole of the Fresnel reflection coefficient looking into the structure. Furthermore, it is shown that Zenneck waves and surface plasmon-polaritons (SPPs) are two manifestations of a pole wave corresponding to different media, and as such are closely related. It is also shown that both surface waves may be set up by illuminating the structure with an inhomogeneous plane wave incident at the complex Brewster angle. The case of a graphene sheet at the interface is also considered and it is shown that this structure supports a highly attenuated SPP. The theoretical development is illustrated and supported by representative numerical results.