Uncovering Extreme Nonlinear Dynamics in Solids Through Time-Domain Field Analysis

TL;DR

This paper demonstrates how time-domain analysis of harmonic fields with sub-cycle resolution reveals complex nonlinear electron dynamics in solids, including rapid regime changes, using simulations and discussing experimental feasibility.

Contribution

It introduces a novel time-domain analysis approach to uncover extreme nonlinear dynamics in solids and explores the interplay of emission mechanisms with potential experimental implementation.

Findings

Time-domain analysis identifies interplay of intra- and interband processes.

Rapid changes in emission mechanisms can occur within a single pulse.

Experimental viability of sub-cycle resolution harmonic field analysis is discussed.

Abstract

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. 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.