Anomalous dispersion and negative group velocity in a coherence-free cold atomic medium
arXiv:0805.2993 · doi:10.1364/JOSAB.25.000C82
Abstract
We have observed the propagation of an approximately 35 ns long light pulse with a negative group velocity through a laser-cooled 85Rb atomic medium. The anomalous dispersion results from linear atom-light interaction, and is unrelated to long-lived ground state coherences often associated with fast light in atomic media. The observed negative group velocity (-c/360) in the Rb magneto-optical trap for a pulse attenuated by less than 50% is in good agreement with the value of dispersion measured independently by an RF heterodyne method. The spectral region of anomalous dispersion is between 15 and 40 MHz, which is an order of magnitude wider than that typically associated with ground-state coherences.
15 pages, 5 figures
References in corpus (7)
- Transparent Anomalous Dispersion and Superluminal Light Pulse Propagation at a Negative Group Velocity
- Generation of entangled states for many multilevel atoms in a thermal cavity and ions in thermal motion
- Steep anomalous dispersion in coherently prepared Rb vapor
- Large negative and positive delay of optical pulses in coherently prepared dense Rb vapor with buffer gas
- Absorption resonance and large negative delay in Rb vapor with buffer gas
- Optimal superluminal systems
- Chasing 'Slow Light'