Compound surface-plasmon-polariton waves guided by a thin metal layer sandwiched between a homogeneous isotropic dielectric material and a structurally chiral material

TL;DR

This paper investigates multiple compound surface plasmon-polariton waves guided by a metal layer between a homogeneous isotropic dielectric and a structurally chiral material, highlighting their properties and potential sensing applications.

Contribution

It introduces the analysis of multiple compound SPP waves in a layered structure with varying metal thickness and dielectric properties, revealing their distinct behaviors and dependencies.

Findings

Compound SPP waves are strongly bound at certain metal thicknesses.

Number of SPP waves depends on the dielectric's permittivity.

Some SPP waves are unaffected by propagation direction.

Abstract

Multiple compound surface plasmon-polariton (SPP) waves can be guided by a structure consisting of a sufficiently thick layer of metal sandwiched between a homogeneous isotropic dielectric (HID) material and a dielectric structurally chiral material (SCM). The compound SPP waves are strongly bound to both metal/dielectric interfaces when the thickness of the metal layer is comparable to the skin depth but just to one of the two interfaces when the thickness is much larger. The compound SPP waves differ in phase speed, attenuation rate, and field profile, even though all are excitable at the same frequency. Some compound SPP waves are not greatly affected by the choice of the direction of propagation in the transverse plane but others are, depending on metal thickness. For fixed metal thickness, the number of compound SPP waves depends on the relative permittivity of the HID material, which can be useful for sensing applications.