Third Harmonic THz Generation from Graphene in a Parallel-Plate Waveguide

TL;DR

This paper explores how to enhance third harmonic terahertz generation from graphene within a parallel-plate waveguide by optimizing parameters, resulting in over 100-fold efficiency improvement compared to normal incidence.

Contribution

It demonstrates a method to significantly boost third harmonic generation efficiency in graphene-based THz devices through waveguide optimization.

Findings

Over 100-fold increase in power efficiency compared to normal incidence

Optimal plate separation and Fermi energy enhance nonlinear response

Maximized nonlinear interaction reduces loss and phase mismatch

Abstract

Graphene as a zero-bandgap two-dimensional semiconductor with a linear electron band dispersion near the Dirac points has the potential to exhibit very interesting nonlinear optical properties. In particular, third harmonic generation of terahertz radiation should occur due to the nonlinear relationship between the crystal momentum and the current density. In this work, we investigate the terahertz nonlinear response of graphene inside a parallel-plate waveguide. We optimize the plate separation and Fermi energy of the graphene to maximize third harmonic generation, by maximizing the nonlinear interaction while minimizing the loss and phase mismatch. The results obtained show an increase by more than a factor of 100 in the power efficiency relative to a normal-incidence configuration for a 2 terahertz incident field.