Pulse-Duration Control of Subcycle Multiband Electron Dynamics Extends the High-Harmonic Cutoff in a Light-Driven Insulator

Hortense Allegre; Simon V. B. Jensen; Joseph J. Broughton; Tim Klee; Yan Li; Jon P. Marangos; Nicolas Tancogne-Dejean; Angel Rubio; John W. G. Tisch; Mary R. Matthews

Pulse-Duration Control of Subcycle Multiband Electron Dynamics Extends the High-Harmonic Cutoff in a Light-Driven Insulator

Optics 2026-08-06 v1 Materials Science Applied Physics

Authors: Hortense Allegre , Simon V. B. Jensen , Joseph J. Broughton , Tim Klee , Yan Li , Jon P. Marangos , Nicolas Tancogne-Dejean , Angel Rubio , John W. G. Tisch , Mary R. Matthews

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Abstract

We demonstrate pathway-selective control of extreme-ultraviolet high-harmonic generation by jointly tuning laser pulse duration ( $5$ - $29$ fs) and intensity ( $0.8$ - $74$ TW/cm $^2$ ). Many-cycle pulses at moderate intensities, $\sim 6$ TW/cm $^2$ , promote cumulative carrier transfer over successive optical cycles, progressively accessing higher conduction bands. In contrast, few-cycle, high-intensity, $\sim 22$ TW/cm $^2$ , pulses drive subcycle multiband dynamics that reach $25$ - $50$ eV photon energies before decoherence can suppress coherent emission. These results reveal pulse duration and intensity as decisive control knobs for high-harmonic emission, opening a route to band-structure-guided pulse design for higher energy extreme-ultraviolet light sources.

Keywords

high-harmonic generation pulse duration multiband dynamics light-driven insulator extreme-ultraviolet carrier transfer

Cite

@article{arxiv.2608.06129,
  title  = {Pulse-Duration Control of Subcycle Multiband Electron Dynamics Extends the High-Harmonic Cutoff in a Light-Driven Insulator},
  author = {Hortense Allegre and Simon V. B. Jensen and Joseph J. Broughton and Tim Klee and Yan Li and Jon P. Marangos and Nicolas Tancogne-Dejean and Angel Rubio and John W. G. Tisch and Mary R. Matthews},
  journal= {arXiv preprint arXiv:2608.06129},
  year   = {2026}
}