Attosecond Transient Absorption Spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy

TL;DR

This paper introduces a novel ghost imaging technique for attosecond transient absorption spectroscopy, enabling high-resolution measurements with broad bandwidth pulses, thus advancing ultrafast X-ray spectroscopy capabilities.

Contribution

The paper presents a new ghost imaging approach that allows sub-bandwidth resolution in attosecond transient absorption spectroscopy, overcoming limitations of broad pulse bandwidths.

Findings

Successfully demonstrated ghost imaging for attosecond absorption measurements

Achieved sub-bandwidth spectral resolution with broad attosecond pulses

Enabled ultrafast electron dynamics probing at X-ray wavelengths

Abstract

The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray transient absorption spectroscopy, where the X-ray absorption spectrum is measured by scanning the central photon energy and recording the resultant photoproducts. The spectral bandwidth inherent to attosecond pulses is wide compared to the resonant features typically probed, which generally precludes the application of this technique in the attosecond regime. In this paper we propose and demonstrate a new technique to conduct transient absorption spectroscopy with broad bandwidth attosecond pulses with the aid of ghost imaging, recovering sub-bandwidth resolution in photoproduct-based absorption measurements.