Nonlinear response of metallic acGNR to an elliptically-polarized terahertz excitation field

TL;DR

This paper provides a theoretical analysis of the nonlinear optical response of metallic armchair graphene nanoribbons to elliptically-polarized terahertz fields, revealing polarization-dependent effects and temperature influences.

Contribution

It introduces a theoretical framework for understanding polarization-dependent nonlinearities in metallic acGNR under terahertz excitation, highlighting new effects at low field strengths.

Findings

Nonlinearities observable at excitation fields around 10^4 V/m.

Enhanced Kerr nonlinearities at low temperatures for extrinsic nanoribbons.

Room temperature third-harmonic nonlinearities increased by 2-3 orders of magnitude.

Abstract

We present a theoretical description of the nonlinear response induced by an elliptically-polarized terahertz beam normally-incident on intrinsic and extrinsic metallic armchair graphene nanorib- bons. Our results show that using a straightforward experimental setup, it should be possible to observe novel polarization-dependent nonlinearities at low excitation field strengths of the or- der of 10 4 V/m. At low temperatures the Kerr nonlinearities in extrinsic nanoribbons persist to significantly higher excitation frequencies than they do for linear polarizations, and at room tem- peratures, the third-harmonic nonlinearities are enhanced by 2-3 orders of magnitude. Finally, the Fermi-level and temperature dependence of the nonlinear response is characterized.