Universitaet Stuttgart


Principal Investigator: Prof. Tilman Pfau


The strong van der Waals interaction among highly excited atoms, so called Rydberg atoms, can be used as an optical non-linarity on the single photon level. Here we want to use this interaction in terms of an excitation blockade, which allows only for a single excitation within the effective range of the  interaction. If one chooses an atomic cloud smaller than the effective range of the blockade, only a single atom in the volume will be excited into a Rydberg state.  In a next step this excitation can be converted into a single photon, which is the most non-classical state of a light field and by this  valuable for all kind of quantum optical applications, as e.g. quantum repeaters.

The technical implementation will feature microscopic vapor cells at room temperature filled with Rubidium or Cesium atoms. The excitation into Rydberg states is achieved via a two-photon transition in an ladder configuration. Finally a third laser will be added to employ a four-wave mixing scheme to extract a single photon.  


Prof. Tilman Pfau (PI)

Dr. Robert Löw (Senior Scientist)

Andreas Kölle (PhD Student)


Jens Honer, Robert Löw, Hendrik Weimer, Tilman Pfau, Hans Peter Büchler, Artificial atoms can do more than atoms: Deterministic single photon subtraction from arbitrary light fields, Phys. Rev. Lett. 107, 093601 (2011)

 T. Baluktsian, C. Urban, T. Bublat, H. Giessen, R. Löw, and T. Pfau, “Fabrication method for micro vapor cells for alkali atoms“, Opt. Lett. 35, 1950 (2010)

 H. Kübler, J. P. Shaffer, T. Baluktsian, R. Löw, and T. Pfau, “Coherent Excitation of Rydberg Atoms in Thermal Vapor Microcells“, Nature Photonics 4, 112 (2010)

 R. Löw, H. Weimer, U. Krohn, R. Heidemann, V. Bendkowsky, B. Butscher, H. P. Büchler, and T. Pfau, “Universal scaling in a strongly interacting Rydberg gas“, Phys. Rev. A 80, 033422 (2009)

 R. Löw and T. Pfau, “Hot atoms rotate light rapidly“, Nature Photon. 3, 197 News and Views (2009)

R. Heidemann, U. Raitzsch, V. Bendkowsky, B. Butscher, R. Löw, L. Santos, T. Pfau, “Evidence for coherent collective Rydberg excitation in the strong blockade regime“, Phys. Rev. Lett. 99, 163601 (2007)