Strongly Interacting Optical and mm-Wave Photons using Rydberg Atoms

Strong interactions between optical and mm-wave photons hold great promise in developing new quantum technologies. Our experiment creates this dual-frequency interaction by hybridizing a cavity optical photon with an atomic Rydberg excitation, which is also strongly coupled to a superconducting 100 GHz cavity. We describe our results, using this high-quality factor mm-wave cavity and the large Rydberg dipole moment to generate nonlinearity on the optical transition. We discuss possible applications of the hybrid system, including optical to mm-wave frequency transduction and generation of atomic spin-squeezed states using the high single-atom cooperativity of the mm-wave transition.