Phase-Matched Emission from Rydberg Atoms Confined in a State-Insensitive Trap: Long-Lived Coherence, Hyperfine Level Measurements, and Hanbury Brown-Twiss Interference

Abstract

Rydberg ensembles have many diverse and important applications for quantum information and quantum optics. For example, Rydberg ensembles can generate non-classical states of light which would be useful in a quantum network, and they could be used as qubits in a future quantum computer. For this reason, this thesis will present investigations of light-matter interactions in Rydberg ensembles. Non-classical states of light, such as single-photon states, are important for many quantum communication protocols. We have performed an experiment that demonstrates the generation of single-photon states from a Rydberg ensemble. We then studied the second-order correlations between this single-photon state of light and an incident coherent field. Under these conditions, we observed Hanbury Brown Twiss interference between the emission from a driven super-atom and a coherent field in the absence of stimulated emission. For a universal quantum computing architecture, coherence times must be much longer than gate operations. We observe ground-Rydberg coherence times in excess of 20 microseconds by using a "magic-wavelength" optical lattice to confine the atoms. Using this coherence time, we measured the differential nuclear-spin-dependent light shifts for principal quantum numbers, n, between n = 30 and n = 65, which is relevant for future high-fidelity Rydberg qubits in optical potentials. Also, we measured the hyperfine constant for atomic Rb to be 35.71 GHz with an uncertainty of 0.18 GHz.