Laser-induced transient opacity in helium nanodroplets probed by single-shot coherent diffraction

TL;DR

This study demonstrates that single-shot coherent diffraction imaging can detect ultrafast, laser-induced electronic structure changes in helium nanodroplets, revealing transient opacity effects with potential applications in ultrafast nanoscale imaging.

Contribution

It extends CDI to observe transient electronic modifications in nanoparticles caused by laser pulses, enabling real-time tracking of ultrafast electron dynamics.

Findings

Laser pulses increase helium nanodroplets' XUV absorption.

Diffraction signal decreases due to electronic structure changes.

Method captures ultrafast electron dynamics in nanosystems.

Abstract

Single-shot coherent diffractive imaging (CDI) with intense short-wavelength light pulses enables the structural characterization of individual nanoparticles in free flight with high spatial and temporal resolution. Conventional CDI assumes that the target object exhibits a linear scattering response and static electronic properties. Here, we extend this approach to investigate transient laser-driven modifications of the electronic structure in individual nanoparticles, imprinted in their time-resolved diffraction patterns. In the presence of a near-infrared laser pulse, we observe a pronounced reduction in the diffraction signal from helium nanodroplets when probed with ultrashort extreme ultraviolet (XUV) pulses. This effect is attributed to a light-field-induced modification of the electronic structure of the droplets, which substantially increases their XUV absorption. Our results demonstrate that single-particle diffraction can capture ultrafast light-driven electron dynamics in nanoscale systems. This paves the way for the spatiotemporal tracking of reversible changes in the electronic properties of nanoscale structures with potential applications in ultrafast X-ray optics, materials science, and all-optical signal processing.

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