Graphene Terahertz Plasmon Oscillators

TL;DR

This paper proposes a new type of terahertz oscillator based on plasmon amplification in graphene, utilizing stimulated emission to achieve high gain and compact device dimensions.

Contribution

It introduces a transmission line model for graphene plasmons including gain and loss, and designs for terahertz plasmon oscillators with threshold conditions.

Findings

Large plasmon gain achievable in graphene at terahertz frequencies

Design guidelines for graphene-based terahertz oscillators

Potential for micron-scale integrated terahertz sources

Abstract

In this paper we propose and discuss coherent terahertz sources based on charge density wave (plasmon) amplification in two dimensional graphene. The coupling of the plasmons to interband electron-hole transitions in population inverted graphene layers can lead to plasmon amplification through stimulated emission. Plasmon gain values in graphene can be very large due to the small group velocity of the plasmons and the strong confinement of the plasmon field in the vicinity of the graphene layer. We present a transmission line model for plasmon propagation in graphene that includes plasmon dissipation and plasmon interband gain due to stimulated emission. Using this model, we discuss design for terahertz plasmon oscillators and derive the threshold condition for oscillation taking into account internal losses and also losses due to external coupling. The large gain values available at terahertz frequencies in graphene can lead to integrated oscillators that have dimensions in the 1-10 micron range.