Single photon zeptosecond interferometry

TL;DR

This paper presents a novel XUV interferometry technique achieving zeptosecond temporal resolution, enabling precise control and measurement of non-local photon correlations with potential applications in quantum electrodynamics and molecular imaging.

Contribution

The authors introduce a superposition-based XUV interferometer capable of zeptosecond precision, surpassing previous temporal resolution limits in photon interferometry.

Findings

Achieved phase and delay control with 52 zs resolution.

Demonstrated phase-locked, spatially separated XUV pulses with 3.5 zs jitter.

Enabled analysis of multi-photon events and non-local correlations.

Abstract

We demonstrate the generation of a train of attosecond XUV pulses that are in a superposition of wavefront states. Such superposition yields a high precision, self-referencing, common path XUV interferometer setup to produce pairs of spatially separated and independently controllable XUV pulses that are locked in phase and time with a temporal jitter of 3.5 zs (zs = zeptoseconds = $10^{-21}$). In our approach, we can independently control the relative phase/delay of the two optical beams with a resolution of 52 zs. Since the jitter is on the order of the Compton time scale, we explore the level of correlation between the non-local photons by comparing different spatial mode superpositions. Further, thanks to the stability of the interferometer we can retrieve the interference pattern through photon counting. Through post-selection of different particle events we can analyze one, two or more photon events. We argue that this zeptosecond level of temporal precision will open the door for new dynamical QED tests at lower intensities while photon counting experiments can also have an impact on the emerging field of quantum light in strong fields. We also discuss the potential impact on other areas, such as time-dependent QED, imaging, measurements of non-locality, and molecular quantum tomography.