Extreme Ultraviolet High-Harmonic Interferometry of Excitation-Induced Bandgap Dynamics in Solids

TL;DR

This paper demonstrates how extreme ultraviolet high-harmonic interferometry can probe ultrafast, excitation-induced changes in the electronic bandgap of solids, revealing phase correlations and enabling potential sub-cycle control.

Contribution

It introduces a novel application of XUV high-harmonic interferometry to study and control bandgap dynamics in solids with ultrafast temporal resolution.

Findings

Transient bandgap modifications correlate with harmonic phase shifts

Experimental results align with analytical and simulation models

Potential for sub-cycle, all-optical control of electronic properties

Abstract

Interferometry is a fundamental technique in physics, enabling precise measurements through the interference of waves. High-harmonic generation (HHG) in solids has emerged as a powerful method for probing ultrafast electronic dynamics within crystalline structures. In this study, we employed extreme ultraviolet (XUV) high-harmonic interferometry with phase-locked XUV pulse pairs to investigate excitation-induced bandgap dynamics in solids. Our experiments on amorphous SiO2 and crystalline MgO, complemented by analytical modeling and semiconductor Bloch equation simulations, reveal a correlation between transient bandgap modifications and variations in the phase of harmonic emission. These findings suggest a potential pathway for sub-cycle, all-optical control of band structure modifications, advancing prospects for petahertz-scale electronic applications and attosecond diagnostics of carrier dynamics.