Strong-field ionization of atoms with bright squeezed vacuum light

TL;DR

This study demonstrates that bright squeezed vacuum light can enhance and protect coherence in strong-field ionization of xenon atoms, revealing quantum-fluctuation effects in ultrafast atomic dynamics.

Contribution

It introduces the use of bright squeezed vacuum as a nonclassical light source to explore quantum effects in strong-field ionization, a novel approach in attosecond physics.

Findings

BSV enhances holographic structures in photoelectron distributions.

Quantum-light-corrected models explain coherence preservation via intrinsic field fluctuations.

Results suggest quantum fluctuations can serve as a noise-resilient mechanism in ultrafast processes.

Abstract

Strong-field ionization is the cornerstone of attosecond physics, which has been extensively studied under coherent-state driving. Recently, the interface between attosecond physics and quantum optics has emerged as a new frontier. Yet, owing to experimental limitations, the role of the quantum nature of light in atomic strong-field ionization has remained unexplored. Here, we demonstrate strong-field ionization of xenon atoms driven by bright squeezed vacuum (BSV) with average pulse energy up to 10 \textmu J. We show that, as a nonclassical state with zero mean field and strong intensity fluctuations, BSV selectively enhances the spider-like holographic structures in the photoelectron momentum distributions. Using a quantum-light-corrected quantum-trajectory Monte Carlo (q-QTMC) model, we attribute this effect to the intrinsic coherence of trajectory pairs emitted within the same subcycle field fluctuation. These dynamically correlated paths exhibit enhanced phase stability and remain robust against dephasing, whereas asynchronous paths are filtered out by field noise. Our results reveal a quantum-fluctuation-induced mechanism for coherence protection in strong-field processes, positioning BSV as an effective coherence filter and establishing a new regime of quantum-enabled noise-resilient ultrafast dynamics.