Imaging moving atoms by holographically reconstructing the dragged slow light

TL;DR

This paper presents a holographic imaging method to reconstruct the complex wavefront of slow light in moving atomic media, enabling precise in situ measurements of atomic density and velocity fields with minimal disturbance.

Contribution

A systematic single-shot holographic reconstruction technique for slow light in moving media, enhancing spectroscopic and phase space analysis in cold atom experiments.

Findings

Successfully reconstructed atomic density and velocity fields from complex imaging data.

Achieved photon shot-noise limited spectroscopic measurements across EIT.

Demonstrated the method on an expanding cloud of cold atoms.

Abstract

The propagation of light in moving media is dragged by atomic motion. The light-drag effect can be dramatically enhanced by reducing the group velocity with electro-magnetically induced transparency (EIT). We develop a systematic procedure to accurately reconstruct the complex wavefront of the slow light with single-shot measurements, enabling precise, photon shot-noise limited spectroscopic measurements of atomic response across EIT even in presence of generic atomic number fluctuations. Applying the technique to an expanding cloud of cold atoms, we demonstrate simultaneous inference of the atomic density distribution and the velocity field from the complex imaging data. This inline imaging technique may assist a wide range of cold atom experiments to access spectroscopic and phase space information with in situ and minimally destructive measurements.