Plasmonics without negative dielectrics

TL;DR

This paper presents a novel approach to mimic plasmonic phenomena using positive-permittivity materials and structural dispersion, avoiding lossy negative-permittivity materials and enabling low-loss plasmonic device design.

Contribution

The authors introduce a method to replicate plasmonic effects with positive-permittivity materials by leveraging structural dispersion and thin metallic wires, expanding design possibilities at lower frequencies.

Findings

Successfully demonstrated surface plasmon polaritons with positive dielectrics

Achieved local plasmonic resonance and cloaking without negative permittivity

Enabled epsilon-near-zero tunneling using conventional materials

Abstract

Plasmonic phenomena are exhibited in light-matter interaction involving materials whose real parts of permittivity functions attain negative values at operating wavelengths. However, such materials usually suffer from dissipative losses, thus limiting the performance of plasmon-based optical devices. Here, we utilize an alternative methodology that mimics a variety of plasmonic phenomena by exploiting the well-known structural dispersion of electromagnetic modes in bounded guided-wave structures filled with only materials with positive permittivity. A key issue in design of such structures is prevention of mode coupling, which can be achieved by implementing thin metallic wires at proper interfaces. This method, which is more suitable for lower frequencies, allows designers to employ conventional dielectrics and highly conductive metals for which the loss is low at these frequencies, while achieving plasmonic features. We demonstrate, numerically and analytically, that this platform can provide surface plasmon polaritons, local plasmonic resonance, plasmonic cloaking and epsilon-near-zero (ENZ)-based tunneling using conventional positive-dielectric materials.