Nonperturbative harmonic generation in graphene from intense midinfrared pulsed light

In solids, high harmonic radiation arises from the subcycle dynamics of electrons and holes under the action of an intense laser field. The strong-field regime opens new opportunities to understand and control carrier dynamics on ultrafast time scales, including the coherent dynamics of quasiparticles such as massless Dirac fermions. Here, we irradiate monolayer and few-layer graphene with intense infrared light to produce nonperturbative harmonics of the fundamental up to the seventh order. We find that the polarization dependence shows surprising agreement with gas-phase harmonics. Using a two-band model, we explore the nonlinear current due to electrons near the Dirac points, and we discuss the interplay between intraband and interband contributions to the harmonic spectrum. This interplay opens new opportunities to access ultrafast and strong-field physics of graphene.Peer reviewed: YesNRC publication: Ye

High-harmonic generation: To the extreme

Peer reviewed: YesNRC publication: Ye

High-harmonic generation in solids: bridging the gap between attosecond science and condensed matter physics

Abstract\u2014We review recent progress in understanding the dominant mechanism driving high-harmonic generation in solids. Three-dimensional two-band single active electron calculations predict that the major emission arises from the recombination of electron-hole pairs upon their creation and acceleration in the laser field, in analogy to atomic high-harmonic generation. The main goal of this study is to review a simple quasi-classical trajectory formalism and use it to better understand the fundamental properties of high-harmonic generation in solids and how they compare to high-harmonic generation in atomic and molecular gases. The simple formalism presents a valuable tool for extending attosecond science fromthe gas to the condensed matter phase. This is demonstrated by discussing the potential synthesis of attosecond pulses from solids.Peer reviewed: YesNRC publication: Ye

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