High-harmonic generation in amorphous solids

TL;DR

This paper reports the first observation of high-harmonic generation in amorphous solids, specifically fused silica, and compares it with crystalline quartz to understand the role of long-range order in HHG.

Contribution

It demonstrates HHG in amorphous solids and decouples the effects of long-range periodicity from atomic composition, advancing understanding of HHG mechanisms in solids.

Findings

HHG observed in amorphous fused silica

Comparison shows long-range order influences HHG efficiency

Implications for developing compact XUV light sources

Abstract

High-order harmonic generation (HHG) in isolated atoms and molecules has been widely utilized in extreme ultraviolet (XUV) photonics and attosecond pulse metrology. Recently, HHG has also been observed in solids, which could lead to important applications such as all-optical methods to image valance charge density and reconstruction of electronic band structures, as well as compact XUV light sources. Previous HHG studies are confined on crystalline solids; therefore decoupling the respective roles of long-range periodicity and high density has been challenging. Here, we report the first observation of HHG from amorphous fused silica. We decouple the role of long-range periodicity by comparing with crystal quartz, which contains same atomic constituents but exhibits long-range periodicity. Our results advance current understanding of strong-field processes leading to high harmonic generation in solids with implications in robust and compact coherent XUV light sources.