Compound Guided Waves That Mix Characteristics of Surface-Plasmon-Polariton, Tamm, Dyakonov-Tamm, and Uller-Zenneck Waves

TL;DR

This paper investigates the formation and properties of compound guided waves resulting from the coupling of various electromagnetic surface waves at interfaces involving chiral and layered dielectric materials, revealing new wave behaviors.

Contribution

It introduces the concept of compound guided waves formed by coupling surface waves at layered interfaces, analyzing their characteristics and dependence on layer thickness and material properties.

Findings

CGWs differ in phase speed and field profiles from ESWs.

Energy distribution of CGWs spans both materials when the layer is thin.

Minimum thickness is required for some CGWs to form.

Abstract

Solutions of the boundary-value problem for electromagnetic waves guided by a layer of a homogeneous and isotropic (metal or dielectric) material sandwiched between a structurally chiral material (SCM) and a periodically multi-layered isotropic dielectric (PMLID) material were numerically obtained and analyzed. If the sandwiched layer is sufficiently thick, the two bimaterial interfaces decouple from each other, and each interface may guide one or more electromagnetic surface waves (ESWs) by itself. Depending on the constitution of the two materials that partner to form an interface, the ESWs can be classified as surface-plasmon-polarition (SPP) waves, Tamm waves, Dyakonov-Tamm waves, or Uller-Zenneck waves. When the sandwiched layer is sufficiently thin, the ESWs for single bimaterial interfaces coalesce to form compound guided waves (CGWs). The phase speeds, propagation distances, and spatial profiles of the electromagnetic fields of CGWs are different from those of the ESWs. The energy of a CGW is distributed in both the SCM and the PMLID material, if the sandwiched layer is sufficiently thin. Some CGWs require the sandwiched layer to have a minimum thickness. Indeed, the coupling between the two faces of the sandwiched layer is affected by the ratio of the thickness of the sandwiched layer to the skin depth in that material and the rates at which the fields of the ESWs guided individually by the two interfaces decay away from their respective guiding interfaces.