Enhanced second harmonic generation and photon drag effect in a doped graphene placed on a two-dimensional diffraction grating

TL;DR

This paper theoretically demonstrates that placing doped graphene on a 2D diffraction grating significantly enhances second harmonic generation and photon drag effects through plasmon excitation and dispersion modulation.

Contribution

It introduces a semi-classical model for nonlinear conductivity and shows how a 2D grating enhances nonlinear optical effects in doped graphene.

Findings

Strong enhancement of second harmonic generation via plasmon polariton excitation.

Photon drag effect is significantly amplified by plasmon excitation at the fundamental frequency.

The induced direct current can flow in both directions depending on plasmon modes.

Abstract

We theoretically investigate the second harmonic generation and photon drag effect induced by an incident plane wave to a doped graphene placed on a two-dimensional diffraction grating. The relevant nonlinear conductivity of the graphene is obtained by a semi-classical treatment with a phenomenological relaxation. The grating acts not only as a plasmon coupler but also as a dispersion modulator of the graphene plasmon. As a result, the second harmonic generation is strongly enhanced by exciting the graphene plasmon polariton of the first- and/or second-harmonic frequencies. The photon drag effect is also strongly enhanced by the excitation of the plasmon at the first-harmonic frequency. The direct current induced by the photon drag effect flows both forward and backward directions to the incident light, depending on the modulated plasmon mode concerned.