Quasiclassical nonlinear plasmon resonance in graphene

TL;DR

This paper explores the unique nonlinear plasmon response in graphene at terahertz frequencies, highlighting how relativistic effects suppress damping and enhance nonlinearity, paving the way for advanced terahertz applications.

Contribution

It reveals how relativistic Klein tunneling suppresses damping and enhances nonlinearity in graphene plasmons, a novel insight into their nonlinear optical behavior.

Findings

Interband plasmon damping is suppressed by Klein tunneling.

Nonlinear intraband response is greatly enhanced near resonance.

Extreme sensitivity of plasmon response to intensity suggests new terahertz devices.

Abstract

Electrons in graphene behave like relativistic Dirac particles which can reduce velocity of light by two orders of magnitude in the form of plasmon-polaritons. Here we show how these properties lead to a peculiar nonlinear plasmon response in the quasiclassical regime of terahertz frequencies. On one hand we show how interband plasmon damping is suppressed by the relativistic Klein tunneling effect. On the other hand we demonstrate huge enhancement of the nonlinear intraband response when plasmon velocity approaches the resonance with the electron Fermi velocity. This extreme sensitivity on the plasmon intensity could be used for new terahertz technologies.