| Cavity Quantum Electrodynamics has long been a proving grounds for the study of the interaction of light with matter. Historically the objective has typically been to couple one atom to one photon as strongly as possible. While this endeavor has yielded a variety of beautiful and groundbreaking results, we take a different approach.;Inspired by the quantum repeater scheme of Duan, Lukin, Cirac and Zoller, we have built a cavity-ensemble experiment, where the strong coupling between the light and the matter is achieved via the combination of the resonant enhancement of a cavity and a collective enhancement of an ensemble. We investigate the capabilities and limitations of such an approach through a number of experiments.;The first experiment we describe is a very-high-quality source of photon pairs of opposite polarization, but otherwise nearly-identical spectral properties. We proceed to a high-fidelity single photon source, and carefully investigate the decoherence mechanisms that limit the performance of such a system. Next we present the cavity-mediated transfer of a single collective excitation between atomic ensembles, and deterministic entanglement generation. Lastly, we present a heralded, polarization preserving quantum memory. All of these experiments depend critically on the strong light-matter coupling afforded by the cavity-ensemble interaction, and require increasingly more sophisticated state control of the atoms.;Finally, we describe our new apparatus, combining a relatively long, high-finesse optical resonator with a 2microm dipole trap. We focus on the technical details of stabilizing the narrow resonator, and discuss briefly a proposal for high efficiency Quantum Non-Demolition photon detection. We conclude with preliminary data demonstrating single-atom detection. |
