https://doi.org/10.1140/epjd/e2010-00172-x
Dispersive and absorptive properties of a Λ-type atomic system with two fold lower-levels
1
Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz, Iran
2
Research Institute for Fundamental Sciences, Tabriz, Iran
3
Department of Physics, Zanjan University, P.O.Box 45195-313, Zanjan, Iran
Corresponding author: a sahrai@tabrizu.ac.ir
Received:
16
February
2010
Revised:
10
May
2010
Published online:
29
June
2010
The dispersion and the absorption properties of a driven four-level Λ-type atomic system is investigated. It is found that the interaction of double-dark states lead to controllable group velocity of the weak probe field by the intensity of driving field and the relative phase between applied fields. Moreover, the transient dispersion, absorption and the group index are also discussed. The required switching time for switching the group velocity of a weak probe field from subluminal to superluminal pulse propagation is then discussed.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010
