Michael V. Pack

Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor.

We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states.

Low-distortion slow light using two absorption resonances

We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike single resonance systems, the dispersive broadening dominates the absorptive broadening which leads to a dramatic increase in the possible group delay. We show that the double resonance systems are excellent candidates for realizing all-optical delay lines. We report on an experiment which achieved up to 50 pulse delays with 40% broadening.

Slow light with large fractional delays by spectral hole-burning in rubidium vapor

We report on the experimental realization of large fractional pulse delays in a hot, Doppler-broadened rubidium vapor. A pump laser burns a deep spectral hole in the inhomogeneously broadened vapor. The delay is shown to be widely tunable by both power broadening the resonance and frequency modulating the pump laser. The simplicity of the scheme opens up the possibility for practical optical delays and buffers.

Implementations of Double-Resonance Slow Light

Recent experiments demonstrating slow light between two absorbing resonances are reviewed as well as some recently demonstrated implementations, including low-light level buffering, image delays and interferometry.

Transients and Rise Times of the Refractive EIT-Kerr Nonlinearity

We observe transients and rise times for the refractive EIT Kerr nonlinearity in Rubidium vapor, and discuss the importance of the rise times for various applications of EIT enhanced optical nonlinearities

Tunable Slow Light in Cesium Vapor

We obtain large fractional pulse delays in a Cesium vapor for a probe centered between two absorption resonances in the hyperfine structure. This delay can be tuned by applying pump fields to the absorption lines.

Slow Light Near Two Absorbing Rb Resonances

We consider group delay and broadening using two strongly absorbing resonances. Large pulse bandwidths and large group delays with small broadening are achieved. We report up to 50 pulse delays with 40% broadening.

Observations cross-absorption modulation mediated by coherent population trapping in hot rubidium vapor

Using the four-level N-system discussed by Schmidt and Imamoglu, Opt. Lett. 21,1936(1996), we observe cross-absorption modulation in hot rubidium atoms. Quantum coherences from coherent population trapping create larger Kerr nonlinearities than conventional three-level cascade systems.