EGAS41 - Swansea University

41 st EGAS CP 115 Gdańsk 2009
Density matrix description of ultra-short light pulses
propagation and the multiple light storage effect in a double Λ
configuration for cold atoms
A.M. Alhasan
Institute of Physics, Faculty of Mathematics and Natural Sciences, Pomeranian University in
S̷lupsk, 76-200 S̷lupsk, Poland.
E-mail: alhasan@apsl.edu.pl,
We investigate the influence of the Multiple Light Storage (MLS) [1] of the quantum
information on the area of initially ultra-short light pulse. The propagation dynamics and
its soliton-like behavior are investigated for the double Λ excitation within the hyperfine
structure of the D1 line in cold sodium and rubidium atoms. The governing equations
are the Maxwell’s field equations for the radiation fields and the Liouville-von Neumann
equations for the density matrix of the dressed atom. We have incorporated the atomic
relaxations both radiation and collisional. The four color propagated pulses are assumed
to be initially on resonance with their respective dipole-allowed transitions. Our numerical
results show that the MLS is responsible for the production as well as the stabilization
of the area for the propagating pulses. In addition we show that the presented optical
soliton-like solution to the reduced Maxwell’s field equations gives a good resemblance
to the Manakov-like solitons [2-4] where in our case the MLS reveals the information
transfer as well as the energy exchange among these solitons. It is to be emphasized
that, in the present study, we have ignored the diffraction terms in the propagation of
the coupled reduced-Maxwell’s field equations. The present analysis is important for
developing optical memory devices as well as optical switches.
References
[1] A.M. Alhasan, Eur. Phys. J. Special Topics 144, 277 (2007)
[2] S.V. Manakov, Sov. Phys. JETP 38, 248 (1974)
[3] C. Anastassiou, M. Segev, K. Steiglitz, J.A. Giordmaine, M. Mitchell, M. Shih, S. Lan,
J. Martin, Phys. Rev. Letts 83, 2332 (1999)
[4] C. Anastassiou, J.W. Fleischer, T. Carmon, M. Segev, K. Steiglitz, Opt. Letts 26,
1498 (2001)
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