Uncovering extreme nonlinear dynamics in solids through time-domain field analysis

• Published in: Physical review. B 2023-02, Vol.107 (5), Article 054302
• Main Authors: Keathley, P. D., Jensen, S. V. B., Yeung, M., Bionta, M. R., Madsen, L. B.
• Format: Article
• Language: English
• Subjects: Atomic & molecular processes in external fields; ATOMIC AND MOLECULAR PHYSICS; Atomic, Molecular & Optical; Collective dynamics; Condensed Matter, Materials & Applied Physics; Density functional theory; Electronic excitation & ionization; Electronic transitions; Frequency conversion; High-order harmonic generation; Light-matter interaction; Multiphoton or tunneling ionization & excitation; Nonlinear Dynamics; Nonlinear optics; Optical transient phenomena; Optics & lasers; Quantum correlations, foundations & formalism; Schroedinger equation; Semiclassical physics; Strong electromagnetic field effects; Strong field ionization & excitation; Strong-field approximation; Strong-field-induced spectra; Ultrafast phenomena; Ultrashort pulses
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.107.054302

Time-domain analysis of harmonic fields with sub-cycle resolution is now experimentally viable due to the emergence of sensitive, on-chip techniques for petahertz-scale optical-field sampling. We demonstrate how such a time-domain, field-resolved analysis uncovers the extreme nonlinear electron dynamics responsible for high-harmonic generation within solids. Time-dependent density functional theory was used to simulate harmonic generation from a solid-state band-gap system driven by near- to mid-infrared waveforms. Particular attention was paid to regimes where both intraband and interband emission mechanisms play a critical role in shaping the nonlinear response. We show that a time-domain analysis of the harmonic radiation fields identifies the interplay between intra- and interband dynamical processes underlying the nonlinear light generation. With further analysis, we show that changes to the dominant emission regime can occur after only slight changes to the peak driving intensity and central driving wavelength. Furthermore, time-domain analysis of harmonic fields also reveals, for the first time, the possibility of rapid changes in the dominant emission mechanism within the temporal window of the driving pulse envelope. Finally, we examine the experimental viability of performing time-domain analysis of harmonic fields with sub-cycle resolution using realistic parameters.