title: Cooperative atom-light interaction in a blockaded Rydberg ensemble.
abstract: By coupling a probe transition to a Rydberg state using electromagnetically induced transparency (EIT) we map the strong dipole-dipole interactions onto an optical field. We characterize the resulting cooperative optical nonlinearity as a function of probe strength and density. We demonstrate good quantitative agreement between the experiment and an N-atom cooperative model for N=3 atoms per blockade sphere and the n=60 Rydberg state. The measured linewidth of the EIT resonance places an upper limit on the dephasing rate of the blockade spheres of <110 kHz.
authors.affiliation: Department of Physics, Durham University, Rochester Building, South Road, Durham DH1 3LE, United Kingdom. j.d.pritchard@durham.ac.uk
authors.forename: J D
authors.initials: JD
authors.lastname: Pritchard
authors.forename: D
authors.initials: D
authors.lastname: Maxwell
authors.forename: A
authors.initials: A
authors.lastname: Gauguet
authors.forename: K J
authors.initials: KJ
authors.lastname: Weatherill
authors.forename: M P A
authors.initials: MP
authors.lastname: Jones
authors.forename: C S
authors.initials: CS
authors.lastname: Adams