Enhancing atom-photon interaction with integrated nanophotonic resonators

We study hybrid devices consisting of thermal atomic vapor and nanophotonic structures for manipulating the interaction between atoms and photons.

We exploit cooperative effects to develop a compact, on-demand and highly efficient single-photon-source using the Rydberg blockade effect. In order to excite Rb atoms to the Rydberg states efficiently, the corresponding light field is locally enhanced by ultralow-loss micro-ring resonators. Due to the large spatial extent of Rydberg atoms, we carefully design the ring resonators to realize sufficient interactions between Rydberg atoms and the evanescent field from the resonator. In order to create individual photons deterministically, we use the Four-Wave-Mixing (FWM) process in the Rydberg blockade regime inside a thermal vapor cell to develop a single-photon-source at room temperature.

To realize this goal, it is necessary to study Rydberg excitation in photonic integrated vapor cells. We excite and detect Rydberg excited Rb atoms with tapered, freestanding waveguides. Tapered narrow waveguides push out evanescent field that enables the excitation of Rydberg atoms. A specially designed, electric circuit patterned vapour cell and a trans-impedance amplifier enables electric read out of single Rydberg excitation.