Towards Strong Coupling Regime with Trapped Barium Ions and a Miniature Optical Cavity

We report our plans and progress towards implementing a cavity quantum electrodynamics (QED) system with barium ions. A strong light atom coupling, that can be achieved with atoms in a high finesse cavity, can be exploited for exploring fast light-atom entanglement generation with applications in quantum computing and networks. Cavity QED in the strong coupling regime can have several applications, such as efficient single photon sources, implementing nodes in a quantum network for quantum communication and exploring non-linear optics at a quantum level.

Small mode volumes that are required for strong coupling between the ion and cavity can be obtained using laser ablated fiber microcavities. We discuss progress and challenges towards integrating microcavities in an ion trap for coupling to barium ion’s strong S-P transition at 493 nm, with the long-term goal of using ion-cavity modules as nodes of a quantum network or qubits of a quantum computer that can be entangled by using photonic flying qubits. Cavities operating at short wavelengths have been hampered by degradation in vacuum. We present results showing stable cavity operation at 493 nm in vacuum at low circulating powers.

Further, we will discuss some of our planned experiments, including fast generation of atom-photon entanglement, fast cavity-assisted state readout and state readout in the dispersive regime. We also present our monolithic ion trap setup and its characterization for stable trapping of barium ions.