Moulding the flow of surface plasmons using conformal and quasiconformal mapping

TL;DR

This paper explores how transformation optics can be used to manipulate surface plasmon flow on metal-dielectric interfaces, demonstrating designs like cloaks and bends with simplified dielectric modifications.

Contribution

It shows that conformal and quasiconformal mappings enable plasmonic device design by only modifying the dielectric's isotropic refractive index, simplifying fabrication.

Findings

Modification of dielectric permittivity and permeability achieves near-perfect plasmon control

Conformal mappings allow device design with only dielectric index engineering

Surface plasmon manipulation is feasible with minimal material anisotropy

Abstract

In this paper we analyze how Transformation Optics recipes can be applied to control the flow of surface plasmons on metal-dielectric interfaces. We study in detail five different examples: a cylindrical cloak, a beam shifter, a right-angle bend, a lens and a ground-plane cloak. First, we demonstrate that only the modification of the electric permittivity and magnetic permeability in the dielectric side can lead to almost perfect functionalities for surface plasmons. We also show that, thanks to the quasi two-dimensional character of surface plasmons and its inherent polarization, the application of conformal and quasiconformal mapping techniques allows the design of plasmonic devices in which only the isotropic refractive index of the dielectric film needs to be engineered.