Quantum nonlinear optics in the strong photon-photon interaction regime

Tomer Danino Zohar, Ofer Firstenberg, Lee Drori and Bankim Chandra Das
Weizmann Institute of Science, Israel

We explore effective photon-photon interactions by coupling light to Rydberg atoms. In the strong-interaction regime, we observe a large (>pi) two-photon phase, genuine three-photon interactions, high-order bound states, and the formation of optical quantum vortices.