Storage and release of subradiant excitations in a dense atomic cloud

TL;DR

This paper demonstrates subradiance in dense cold atomic clouds, showing atom number as the key factor, and introduces a method to release stored excitations, advancing light storage technologies.

Contribution

It provides experimental validation of subradiance governed solely by atom number and demonstrates a technique to release stored subradiant excitations.

Findings

Subradiance observed in dense cold atomic ensembles.

Atom number is the primary parameter controlling subradiance.

Developed a method to release stored subradiant excitations.

Abstract

We report the observation of subradiance in dense ensembles of cold $^{87}$Rb atoms operating near Dicke's regime of a large number of atoms in a volume with dimensions smaller than the transition wavelength. We validate that the atom number is the only cooperativity parameter governing subradiance. We probe the dynamics in the many-body regime and support the picture that multiply-excited subradiant states are built as a superposition of singly-excited states that decay independently. Moreover, we implement an experimental procedure to release the excitation stored in the long-lived modes in a pulse of light. This technique is a first step towards the realization of tailored light storing based on subradiance.