Enhancing Cutoff Energy of Solid High-Harmonic Generation from Bonding Length Perspective

TL;DR

This paper demonstrates that by applying strain to alter bond lengths in solids, the cutoff energy of high-harmonic generation can be significantly increased, enhancing the efficiency of attosecond light sources.

Contribution

It introduces a novel approach of using bond length engineering via strain to control and enhance high-harmonic cutoff energies in solids.

Findings

Cutoff energy increases by nearly one third with 7.5% bond length compression.

Band gap widening under strain leads to higher interband cutoff energy.

The effect is independent of specific material properties.

Abstract

High-harmonic generation (HHG) from solid state offers promising potential for attosecond optics with enhanced efficiency and compact configurations. However, Current implementations face critical limitations imposed by material damage thresholds, directly restricting spectral cutoff energies in nonperturbative regime. In this study, we control the cutoff energy through tailoring the bond length of materials, which is available by experimental strain. Employing real-time time-dependent density theory (rt-TDDFT) simulations, we find that the cutoff energy increases by nearly one third under a bond length compression of 7.5%. Our results reveal that it originates the band gap widening inducing the enhancement of interband cutoff energy, which is material-independent. This work provides novel theoretical insights for optimizing extreme ultraviolet sources, advancing potential applications in attosecond physics.