https://doi.org/10.1140/epjd/e2006-00141-0
Controllable shape-matched propagation of two signal beams in a double-Λ atomic ensemble
1
Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing, 100875, P.R. China
2
CCAST (World Laboratory), P.O. Box 8730, Beijing, 100080, P.R. China
3
The Abdus Salam International Centre for Theoretical Physics, 34014 Trieste, Italy
Corresponding author: a wangkg@bnu.edu.cn
Received:
14
October
2005
Revised:
10
March
2006
Published online:
21
June
2006
We study a four-level double-Λ atomic ensemble interacting with two time-dependent signal fields and two stationary control fields. Though, in each Λ channel, a pair of signal and control fields couple resonantly with the two lower levels of atoms, the occurrences of electromagnetically induced transparency (EIT) is affected by the coherence of the four fields. In the discussion of atomic susceptibilities, we show that the quantum coherence between the two lower levels can be either formed or released according to the phase matching of the four fields. We analyze the propagation equation of the two signal fields, and find two characteristic solutions: the stationary transmission wave and the transient decay wave. The former corresponds to a correlated EIT effect in which two signal pulses are shape-matched. The latter is an opposite effect to the correlated EIT in which two pulses quench simultaneously, thus named as the correlated two-signal absorption (CTSA). We propose the CTSA condition in correspondence with the EIT condition. The numerical simulation shows that the double-Λ configuration is capable of manipulating synchronous optical signals and thus provides multiplicity and versatility in quantum information process.
PACS: 42.50.Gy – Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption / 42.50.Hz – Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift / 42.65.-k – Nonlinear optics
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006