A high-repetition rate attosecond light source for time-resolved coincidencespectroscopy

TL;DR

This paper introduces a 200 kHz attosecond light source enabling advanced time-resolved spectroscopy and coincidence measurements, significantly improving data statistics and resolution for ultrafast electron dynamics studies.

Contribution

The work presents the first high-repetition-rate attosecond source combined with a stabilized interferometer and advanced detectors, enabling new experiments in electron correlation and ultrafast dynamics.

Findings

Achieved 200 kHz repetition rate for attosecond pulses.

First coincidence measurement of helium double ionization with full angular resolution.

Demonstrated the exploration of intermediate pulse train regimes in attosecond science.

Abstract

Attosecond pulses, produced through high-order harmonic generation in gases, have been successfully used for observing ultrafast, sub-femtosecond electron dynamics in atoms, molecules and solid state systems. Today's typical attosecond sources, however, are often impaired by their low repetition rate and the resulting insufficient statistics, especially when the number of detectable events per shot is limited. This is the case for experiments where several reaction products must be detected in coincidence, and for surface science applications where space-charge effects compromise spectral and spatial resolution. In this work, we present an attosecond light source operating at 200 kHz, which opens up the exploration of phenomena previously inaccessible to attosecond interferometric and spectroscopic techniques. Key to our approach is the combination of a high repetition rate, few-cycle laser source, a specially designed gas target for efficient high harmonic generation, a passively and actively stabilized pump-probe interferometer and an advanced 3D photoelectron/ion momentum detector. While most experiments in the field of attosecond science so far have been performed with either single attosecond pulses or long trains of pulses, we explore the hitherto mostly overlooked intermediate regime with short trains consisting of only a few attosecond pulses.e also present the first coincidence measurement of single-photon double ionization of helium with full angular resolution, using an attosecond source. This opens up for future studies of the dynamic evolution of strongly correlated electrons.