Principles of Fast and Slow Light Propagation

Qiguang Yang, Jaetae Seo, Wei Gong +10 more

Federico Tommasi, Emilio Ignesti, Lorenzo Fini +1 more

We present an experimental realization of slow and fast light schemes for a few ns long optical pulses that makes use of incoherent interactions in an atomic medium. The combination of such different schemes allows us to demonstrate that the propagation delay acquired in the slow light stage, can be completely recovered in a fast light one. The use of an incoherent interactions scheme makes the control of the propagation dynamics of light pulses easer to realize. Delays up to 13 ns, in slow light regime, and advances up to 500 ps, in fast light regime, are reported when the stages work individually for a 3 ns long pulse. When both stages are switched-on the fast light stage is able to recover a previously induced delay and even to produce an extra advance, with an overall advance up to 1 ns. Since every optical transmission line needs an amplification system to overcome the unavoidable losses, the results suggest the opportunity and perspective of a proper tailoring of the amplification stage for data timing purposes.

B. Macke, Bernard Ségard

We study the propagation of light pulses in an absorbing medium when the frequency of their carrier coincides with a zero of the refractive index dispersion. Although slow light and, a fortiori, fast light are not expected in such conditions, we show that both can be obtained by selecting particular phase components of the transmitted field. Analytical expressions of the resulting signals are obtained by a procedure of periodic continuation of the incident pulse, and a proof of principle of the predicted phenomena is performed by means of a very simple electrical network; the transfer function of which mimics that of the medium.

R. Y. Chiao, Claus Ropers, Daniel R. Solli +1 more

A. M. Akulshin, Russell McLean

Atomic media have played a major role in studies of fast light. One of their attractive features is the ability to manipulate experimental parameters to control the dispersive properties that determine the group velocity of a propagating light pulse. We give an overview of the experimental methods, based on both linear and nonlinear atom-light interaction, that have produced superluminal propagation in atomic media, and discuss some of the significant theoretical contributions to the issues of pulse preservation and reconciling faster-than-light propagation and the principle of causality. The comparison of storage of light, enhanced Kerr nonlinearity and efficient wave mixing processes in slow and fast light atomic media illustrates their common and distinct features.

Hamid Reza Hamedi