Current-controlled light scattering and asymmetric plasmon propagation in graphene

TL;DR

This paper demonstrates how applying a DC current to graphene can control plasmon propagation, enabling asymmetric propagation lengths and potential applications in sensing and modulation of mid-infrared light.

Contribution

It introduces a method to manipulate graphene plasmons with DC current, lifting degeneracy and creating distinct forward and backward modes with different propagation characteristics.

Findings

DC current lifts plasmon degeneracy in graphene.

Forward plasmon propagation length is enhanced by current.

Backward plasmon propagation length is suppressed.

Abstract

We demonstrate that plasmons in graphene can be manipulated using a DC current. A source-drain current lifts the forward/backward degeneracy of the plasmons, creating two modes with different propagation properties parallel and antiparallel to the current. We show that the propagation length of the plasmon propagating parallel to the drift current is enhanced, while the propagation length for the antiparallel plasmon is suppressed. We also investigate the scattering of light off graphene due to the plasmons in a periodic dielectric environment and we find that the plasmon resonance separates in two peaks corresponding to the forward and backward plasmon modes. The narrower linewidth of the forward propagating plasmon may be of interest for refractive index sensing and the DC current control could be used for the modulation of mid-infrared electromagnetic radiation.