QUROPE Quantum Information Processing and Communication in Europe

FOM Meeting of the Dutch Physical Society,

Veldhoven, The Netherlands,  21-23 Januray 2014

Philippe Grangier (Institut d'Optique)

Using ensembles of cold Rydberg atoms to  process single photon light pulses.

Annual Conference of the Korean Physical Society,

Korea, 28 october-1 november 2013

Philippe Grangier (Institut d'Optique)

Quantum Optics and Quantum Information with Non-Gaussian States of Light

Conference on Quantum Information and Quantum Control,

12-16 August 2013, Toronto , Canada

Philippe Grangier (Institut d'Optique)

"Rydberg blockade for manipulating atomic and photonic qubits"

LPHYS, Nijni Novgorod, Russia,  29 July -  2 August 2013

Philippe Grangier (Institut d'Optique)

"Rydberg blockade for manipulating atomic and photonic qubits"

QIPC Florence, Italy,  1-5 July 2013

Philippe Grangier (Institut d'Optique)

"Rydberg blockade for manipulating atomic and photonic qubits"

Gordon research Conference on  Atomic Physics, 24-28 June 2013

Salve Regina University, Newport, USA

Philippe Grangier (Institut d'Optique)

"Manipulating Atoms and Photons using Rydberg Blockade"

We theoretically investigate the quantum statistical properties of light transmitted through an atomic medium with strong optical nonlinearity induced by Rydberg–Rydberg van der Waals interactions. In our setup, atoms are located in a cavity and nonresonantly driven on a two-photon transition from their ground state to a Rydberg level via an intermediate state by the combination of the weak signal field and a strong control beam.

We experimentally demonstrate that a nonclassical state prepared in an atomic memory can be efficiently transferred to a single mode of free-propagating light. By retrieving on demand a single excitation from a cold atomic gas, we realize an efficient source of single photons prepared in a pure, fully controlled quantum state. We characterize this source using two detection methods, one based on photon-counting analysis and the second using homodyne tomography to reconstruct the density matrix and Wigner function of the state.

We investigate dispersive optical nonlinearities that arise from a Rydberg excitation blockade in cold Rydberg gases. We consider a two-photon transition scheme and study the nonlinear response to a weak optical probe in the presence of a strong control beam. For very low probe fields, the dominant nonlinearities are of the third order and they can be evaluated in a steady-state regime.

The paper, authored by S. van Frank, A. Negretti, T. Berrada, R. Bücker, S. Montangero, J.-F. Schaff, T. Schumm, T. Calarco, J.