Implementations of slow light using double-resonances

Thesis (Ph. D.)--University of Rochester. Dept. of Physics and Astronomy, 2008.Many practical applications of slow optical pulse propagation (slow light) require that a pulse be delayed by many times its temporal width, or equivalently that the product of the pulse’s delay and bandwidth greatly exceed unity. Implementations in optical buffering, quantum memories, remote sensing, interferometry, and chip-scale optical circuits, for example, would be enabled by large delay-bandwidth products. While in the last decade researchers have succeeded in slowing optical pulses by up to a factor of 10 7, for a variety of reasons they have not made exceptional progress in demonstrating large delay-bandwidth products. The present work investigates the slow propagation of optical pulses whose carrier frequency lies between two strongly absorbing Lorentzian resonances in an atomic vapor and how this system mitigates the delay-bandwidth problem. My studies show that owing to the symmetry of the double-resonance configuration, pulse distortion is reduced in such a way that multiple pulse delays are possible. Detailed theoretical and experimental investigations are undertaken to understand the physical origins of this effect, revealing an important interplay between absorption and dispersion which allows for large delay-bandwidth products. Specifically, I report on two proof-of-principle experiments demonstrating tens of pulse delays using the incoherent ground-state hyperfine resonances in 85 Rb and Cs, and develop a concise model based on dispersion theory using Feynman diagrams. Several implementations of the scheme are then demonstrated experimentally, including applications to imaging, interferometry, and quantum entanglement. It is shown that double-resonances may also be prepared in a coherent fashion, allowing for tunable resonance parameters, fast switching, and applications in nonlinear optics. Finally, it is shown that coherent preparation of an atomic vapor may extend the results on slow images to much longer time scales, where atomic diffusion begins to dominate image distortion. A 4f imaging method using analog Fourier optics is shown to mitigate this complication. My work concludes with a summary of the principle results and a discussion of their implications