Terahertz Harmonic Generation in Graphene

TL;DR

This paper demonstrates that graphene can generate terahertz harmonics through resonant charge carrier transport modulated by interdigitated gates, enabling tunable high-Q harmonic generation in the terahertz range.

Contribution

It introduces a novel method to produce tunable terahertz harmonics in graphene using spatially and temporally modulated scattering with interdigitated gates.

Findings

Resonances occur when a-c field period matches carrier drift time.

Terahertz range resonances with high Q-factors are achievable.

Harmonic generation can be tuned by gate spacing.

Abstract

We show that charge carrier transport in graphene exhibit sharp resonances in the presence of spatially and temporarily modulated scattering. Resonances occur when the period of an applied a-c field corresponds to the time taken by quasi-ballistic carriers to drift over a spatial scattering period, provided the latter is shorter than the distance taken by carriers to emit an optic phonon. We show that such system can be achieved with interdigitated gates energized with an a-c bias on graphene layers. Gate separation and fields to achieve ballistic transport would result in resonances in the terahertz range, with the generation of higher harmonics characterized by large Q-factors, which are tunable with gate spacing.