An expose of Zenneck waves and surface plasmon polaritons

Abstract

In this paper, the distinction between Zenneck waves and surface plasmon polaritons is illustrated. Both are evanescent waves. The surface plasmon needs to be excited by an electron beam which can be effectively generated by a source of electrons or a quasiparticle like an evanescent wave which can tunnel through the medium and thus excite the electrons. This electron wave produces its own electromagnetic wave. Hence, the surface plasmon propagates at the interface between a metal and a dielectric at petahertz frequencies when the conditions are right. The Zenneck waves are produced at the zero of the reflection coefficient of an incident TM wave on an air-dielectric interface whereas the surface wwaves related to the surface plasmons are produced when the reflection coefficient is infinite. For the Zenneck wave, the evanescent transverse field components do not change appreciably with frequency as the Brewster phenomenon occurring at the zero of the TM reflection coefficient is independent of frequency, whereas for a surface plasmon, with an increase of the frequency, the surface wave is more closely coupled to the surface.