Rydberg tomography of an ultra-cold atomic cloud

TL;DR

This paper introduces a spatial imaging method to visualize the Rydberg blockade effect in an ultra-cold atomic cloud, revealing how interactions influence excitation profiles and dynamics.

Contribution

The study presents a novel technique for spatially visualizing Rydberg blockade in an inhomogeneous cold atom gas, linking excitation profiles to atomic density and interactions.

Findings

Blockade modifies the Rydberg excitation profile width.

Excitation timescale depends on local atomic density.

Method enables direct visualization of Rydberg interactions.

Abstract

One of the most striking features of the strong interactions between Rydberg atoms is the dipole blockade effect, which allows only a single excitation to the Rydberg state within the volume of the blockade sphere. Here we present a method that spatially visualizes this phenomenon in an inhomogeneous gas of ultra-cold rubidium atoms. In our experiment we scan the position of one of the excitation lasers across the cold cloud and determine the number of Rydberg excitations detected as a function of position. Comparing this distribution to the one obtained for the number of ions created by a two-photon ionization process via the intermediate 5P level, we demonstrate that the blockade effect modifies the width of the Rydberg excitation profile. Furthermore, we study the dynamics of the Rydberg excitation and find that the timescale for the excitation depends on the atomic density at the beam position.