Carrier heating and high-order harmonics generation in doped graphene by a strong ac electric field

TL;DR

This paper theoretically investigates how strong ac electric fields cause carrier heating and generate high-order harmonics in doped graphene, revealing efficient third harmonic generation at room temperature.

Contribution

It introduces a theoretical model describing carrier heating and high-order harmonic generation in doped graphene under strong ac fields, focusing on the frequency regime above energy relaxation but below scattering rates.

Findings

High-order harmonics are generated due to electron heating.

Third harmonic conversion efficiency is about 10^{-7}.

Effective harmonic generation occurs at room temperature with specific doping and pumping conditions.

Abstract

The nonlinear response of electrons (holes) in doped graphene on ac pumping is considered theoretically for the frequency region above the energy relaxation rate but below the momentum and carrier-carrier scattering rates. Temporally-dependent heating of electrons by a strong ac field, which is described within the energy balance approach, leads to an effective generation of high-order harmonics. The efficiency of up-conversion of the 1 mm radiation into the third harmonic by a single-layer graphene is about 10^{-7} at pumping level ~100 kW/cm^2, room temperature, and concentration ~5 x 10^{11} cm^{-2}.