High-order harmonic generation from gapped graphene: perturbative response and transition to non-perturbative regime

TL;DR

This paper investigates high-order harmonic generation in gapped graphene, analyzing the transition from perturbative to non-perturbative regimes using a time-dependent approach across relevant photon energies.

Contribution

It provides a detailed analysis of the transition from perturbative to non-perturbative HHG in gapped graphene using an explicit time-dependent method.

Findings

Full HHG spectrum obtained

Perturbative harmonic response characterized

Transition point between regimes identified

Abstract

We consider the interaction of gapped graphene in the two-band approximation using an explicit time-dependent approach. In addition to the full high-order harmonic generation (HHG) spectrum, we also obtain the perturbative harmonic response using the time-dependent method at photon energies covering all the significant features in the responses. The transition from the perturbative to the fully non-perturbative regime of HHG at these photon energies is studied in detail.