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

TL;DR

This paper investigates multiple compound surface plasmon-polariton waves guided by a metal layer between a homogeneous dielectric and a multilayered dielectric, revealing their properties and potential for optical sensing.

Contribution

It introduces the existence and characteristics of multiple compound SPP waves in a novel layered structure, including their polarization, phase speed, and field profiles.

Findings

Multiple SPP waves exist at a fixed frequency for any metal thickness.

Some SPP waves are p-polarized, others are s-polarized, with different phase speeds and attenuation.

The number of SPP waves depends on the dielectric properties and layer thicknesses.

Abstract

Multiple p- and s-polarized compound surface plasmon-polariton (SPP) waves at a fixed frequency can be guided by a structure consisting of a metal layer sandwiched between a homogeneous isotropic dielectric (HID) material and a periodic multilayered isotropic dielectric (PMLID) material. For any thickness of the metal layer, at least one compound SPP wave must exist. It possesses the p-polarization state, is strongly bound to the metal/HID interface when the metal thickness is large but to both metal/dielectric interfaces when the metal thickness is small. When the metal layer vanishes, this compound SPP wave transmutes into a Tamm wave. Additional compound SPP waves exist, depending on the thickness of the metal layer, the relative permittivity of the HID material, and the period and the composition of the PMLID material. Some of these are p polarized, the others being s polarized. All of them differ in phase speed, attenuation rate, and field profile, even though all are excitable at the same frequency. The multiplicity and the dependence of the number of compound SPP waves on the relative permittivity of the HID material when the metal layer is thin could be useful for optical sensing applications.