Cooperative atom-light interaction in a blockaded Rydberg ensemble

TL;DR

This paper demonstrates how strong dipole-dipole interactions in a Rydberg ensemble induce cooperative optical non-linearity, requiring an N-atom model for accurate description, with experimental validation and limits on dephasing rates.

Contribution

It introduces an N-atom cooperative model for Rydberg blockade effects and validates it experimentally, surpassing mean-field approximations.

Findings

Good quantitative agreement with three atoms per blockade

Upper limit on dephasing rate of 110 kHz

Observation of cooperative optical non-linearity

Abstract

By coupling a probe transition to a Rydberg state using electro-magnetically induced transparency (EIT) we map the strong dipole-dipole interactions onto an optical field. We characterize the resulting cooperative optical non-linearity as a function of probe strength and density. We show that the effect of dipole blockade cannot be described using a mean-field but requires an $N$-atom cooperative model. Good quantitative agreement is obtained for three atoms per blockade with the $n=60$ Rydberg state. We place an upper-limit on the dephasing rate of the blockade spheres of $<110$ kHz.