Plasmonic waveguides with hyperbolic multilayer cladding

TL;DR

This paper explores plasmonic waveguides with hyperbolic multilayer cladding, analyzing their resonant modes and absorption properties to inform better design strategies that minimize losses.

Contribution

It provides a detailed calculation of eigenmodes in multilayer hyperbolic claddings without homogenization, revealing how to avoid resonant widths to reduce absorption.

Findings

Resonant eigenmodes match features in waveguide dispersion.

Strong absorption occurs at specific resonant widths.

Designing away from resonant widths reduces absorption.

Abstract

Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any homogenization, we calculate the resonant eigenmodes of the finite-width cladding layers, and find agreement with the resonant features in the dispersion of the cladded waveguides. We show that at the resonant widths, the propagating modes of the waveguides are coupled to the cladding eigenmodes and hence, are strongly absorbed. By avoiding the resonant widths in the design of the actual waveguides, the strong absorption can be eliminated.