Sebastian Hofferberth

Rydberg quantum optics exploits the Rydberg blockade effect in atomic ensembles to create an effective interaction between individual optical photons. Coherent mapping of the Rydberg interaction between atoms onto photons propagating through the medium has enabled the realization of photon-photon gates, single-photon level circuit components such as optical transistors and switches and the study of strongly correlated few-body systems of photons.

To date experiments have used alkali atomic species such as Rb or Cs, because of well-established laser cooling and manipulation techniques. Earth-alkaline-(like) atoms such as Sr or Yb offer unique new properties both for initial cooling and trapping as well as novel Rydberg physics. In particular, bosonic Yb offers an ideal level scheme for Rydberg quantum optics, with well-matched excitation wavelengths and the complete absence of fine- and hyper-fine structure in Rydberg S-states.

In this talk I will give an overview on Rydberg quantum optics and present some results from our group, such as the observation of three-photon collisions and deterministic photon-subtraction. I will then present our new effort employing ultracold Yb for Rydberg physics. I will briefly introduce our experiment apparatus combining fast production of laser-cooled Yb with Rydberg excitation and single-photon & -ion detection and then discuss our first observations of Rydberg-physics in Yb.