Highly Confined Hybrid Spoof Surface Plasmons in Ultra-thin Metal/Dielectric Heterostructures

TL;DR

This paper predicts and demonstrates highly confined spoof surface plasmons in metal/dielectric heterostructures, enabling applications like perfect absorption and enhanced emission, with tunable spectral and field properties.

Contribution

It introduces a new class of spoof surface plasmons in perforated metal films coated with dielectric layers, with tunable confinement and spectral characteristics.

Findings

Spoof surface plasmons can be tuned by hole geometry.

These modes enable perfect absorption in semiconductor films.

Modes exist both above and below the light line.

Abstract

Highly confined "spoof" surface plasmon-like (SSP) modes are theoretically predicted to exist in a perforated metal film coated with a thin dielectric layer. Strong modes confinement results from the additional waveguiding by the layer. Spectral characteristics, field distribution, and lifetime of these SSPs are tunable by the holes' size and shape. SSPs exist both above and below the light line, offering two classes of applications: "perfect" far-field absorption and to efficient emission into guided modes. It is experimentally shown that these plasmon-like modes can turn thin, weakly-absorbing semiconductor films into perfect absorbers.