The influence of the atomic relaxation on the resonant propagation of short light pulses

Entropy Associated with Information Storage and Its Retrieval

“…It seems to us that one could use the maximum or the minimum entropy [45] value reached in the atomic system as a critical value for the breakup of the local stabilization of short optical pulses in the double-Λ system. This is important, since the area theorem [46][47][48][49][50] does not hold in multilevel systems with soliton-like solutions of the reduced Maxwell-Bloch equations [51]. In terms of entropy, we would be able to find when the pulses in the multilevel system stabilize or collapse to fractional nπ pulses in area.…”

Energy spectrum of the light scattered by the S 1/2 - P 1/2 atom interacting with a propagating light pulse

“…where a complex function v(z, τ ) denotes a coupling of the atom and the radiation field, ∆ = ω 0 − ω 21 is the detuning of the pulse carrier frequency ω 0 from the atomic transition frequency ω 21 , α is the propagation coefficient [2,6] and τ denotes the retarded time, i.e., τ = t − z/c. The function v(z, τ ) is proportional to the complex envelope of the pulse.…”

“…We assume that optically active atoms are fixed in space, i.e., we neglect the inhomogeneous broadening due to the Doppler effect. The one-dimensional propagation of the linearly polarized laser pulse in such a medium is described, in the framework of the slowly varying envelope approximation (SVEA) and the rotating wave approximation (RWA) [1], by the MaxwellBloch equation [2,6,7] …”

“…Otherwise this spectrum could be dominated by the free spontaneous decay contribution having a simple one-peak structure. Quite recently the propagation of the pulses, which duration were comparable with the relaxation times, in the medium of fixed atoms was analyzed numerically [6][7][8]. It was shown that the area of such long pulses stabilizes temporarily near the value 2nπ which reminds the famous area theorem [1].…”

“…This is not the case in the considered model. The free induction decay is mainly responsible for the area stabilization effect discussed in [6,7]. The pulse envelope is drastically changed in the course of the propagation.…”