Tailoring the energy distribution and loss of 2D plasmons

TL;DR

This paper analytically investigates how to control the energy distribution of 2D plasmons, especially in graphene, by manipulating loss and geometry, enabling advanced nanophotonic applications.

Contribution

It introduces a method to tailor energy confinement and propagation of graphene plasmons through loss engineering and parity-time symmetry concepts.

Findings

Energy confinement in graphene plasmons can exceed 50%.

Loss tuning enables control over energy distribution and transparency.

Loss-induced plasmonic transparency is demonstrated.

Abstract

The ability to tailor the energy distribution of plasmons at the nanoscale has many applications in nanophotonics, such as designing plasmon lasers, spasers, and quantum emitters. To this end, we analytically study the energy distribution and the proper field quantization of 2D plasmons with specific examples for graphene plasmons. We find that the portion of the plasmon energy contained inside graphene (energy confinement factor) can exceed 50%, despite graphene being infinitely thin. In fact, this very high energy confinement can make it challenging to tailor the energy distribution of graphene plasmons just by modifying the surrounding dielectric environment or the geometry, such as changing the separation distance between two coupled graphene layers. However, by adopting concepts of parity-time symmetry breaking, we show that tuning the loss in one of the two coupled graphene layers can simultaneously tailor the energy confinement factor and propagation characteristics, causing the phenomenon of loss-induced plasmonic transparency.