We investigate realistic atomic systems whose dispersion at line center switches from positive to negative and vice versa, as a particular experimental parameter is changed. We concentrate on those systems which have low probe absorption or gain at line center leading to a high figure of merit, and simultaneously have low pump absorption. For this purpose, we study both open and artificially closed ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=1$ and ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=2$ transitions in ${}^{87}\mathrm{Rb},$ in the absence and presence of an applied magnetic field. We find that the preferred system for observing switchover in the sign of the dispersion from positive to negative, as the pump Rabi frequency increases, is the open near-degenerate ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=1$ system. In the presence of Doppler broadening, the dispersion is positive for all realistic experimental parameters. Thus the switchover in the sign of the dispersion is only observable in the absence of Doppler broadening.We investigate realistic atomic systems whose dispersion at line center switches from positive to negative and vice versa, as a particular experimental parameter is changed. We concentrate on those systems which have low probe absorption or gain at line center leading to a high figure of merit, and simultaneously have low pump absorption. For this purpose, we study both open and artificially closed ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=1$ and ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=2$ transitions in ${}^{87}\mathrm{Rb},$ in the absence and presence of an applied magnetic field. We find that the preferred system for observing switchover in the sign of the dispersion from positive to negative, as the pump Rabi frequency increases, is the open near-degenerate ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=1$ system. In the presence of Doppler broadening, the dispersion is positive for all realistic experimental parameters. Thus the switchover in the sign of the dispersion is only observable in the absence of Doppler broadening.

Physical Review AOct 14, 200343 citations

On the Realization of Negative (Anomalous) Dispersion Without Absorption

Andreas Wicht, Oliver Sascha Brozek, Harald Klausing +4 more

European Quantum Electronics Conference (EQEC)Jan 1, 19960 citations

Electric and Magnetic Coherences: Analysis in a Four-Level Atomic System under a Magneto-Shaped Field

Nadia Boutabba, Hazrat Ali

Abstract In this work, we investigate the dispersion-absorption spectra in a left handed medium under various magnetic shaped pulses. The system is a multi-level atom, in which the levels are coherently controlled by a weak and a strong field. Additionally, the ground state is related to an intermediate transition via a magneto-shaped field.We analyze the four level atom while first by considering the magnetic field as a quotient of the double exponential wave form, a difference of Gaussian and then as a continuous wave form. This enables us to study the dynamics of the coherence in the system. therefore, in contrast with the classical scenario where the magnetic field is taken as a constant, we observe a clear influence of the shaped magnetic field on the dispersion-absorption of the probe. We get an enhancement of about 2.5 times in the positive dispersion while we obtain 8 times enhancement in the negative dispersion. Lastly, with a shaped magnetic field, the probe dispersion, which is positive for a positive detuning and negative for a negative detuning, abruptly changes in the opposite direction.Abstract In this work, we investigate the dispersion-absorption spectra in a left handed medium under various magnetic shaped pulses. The system is a multi-level atom, in which the levels are coherently controlled by a weak and a strong field. Additionally, the ground state is related to an intermediate transition via a magneto-shaped field.We analyze the four level atom while first by considering the magnetic field as a quotient of the double exponential wave form, a difference of Gaussian and then as a continuous wave form. This enables us to study the dynamics of the coherence in the system. therefore, in contrast with the classical scenario where the magnetic field is taken as a constant, we observe a clear influence of the shaped magnetic field on the dispersion-absorption of the probe. We get an enhancement of about 2.5 times in the positive dispersion while we obtain 8 times enhancement in the negative dispersion. Lastly, with a shaped magnetic field, the probe dispersion, which is positive for a positive detuning and negative for a negative detuning, abruptly changes in the opposite direction.

Dec 21, 20230 citations

Wave packets in an absorptive and strongly dispersive medium

D. Anderson, Jan I. H. Askne, M. Lisak

Sep 1, 19740 citations

Absorption-free superluminal light propagation in a V-type system

Kh. Saaidi, Bahareh Ruzbahani, S. W. Rabiei +1 more

Dispersion and absorption properties of a weak probe field in a three-level V-type atomic system is studied. By application of indirect incoherent pump fields the effect of populating upper levels on optical properties of the atomic medium in presence of a strong coherent pump field is investigated. It is shown that the slope of dispersion changes from positive to negative just by changing the intensity of the coherent or indirect incoherent pump fields. It is demonstrated that the absorption-free subluminal and superluminal light propagation appears in this system.Dispersion and absorption properties of a weak probe field in a three-level V-type atomic system is studied. By application of indirect incoherent pump fields the effect of populating upper levels on optical properties of the atomic medium in presence of a strong coherent pump field is investigated. It is shown that the slope of dispersion changes from positive to negative just by changing the intensity of the coherent or indirect incoherent pump fields. It is demonstrated that the absorption-free subluminal and superluminal light propagation appears in this system.

arXiv:1001.3131Jan 18, 20100 citations

{}^{87}\mathrm{Rb},

in the absence and presence of an applied magnetic field. We find that the preferred system for observing switchover in the sign of the dispersion from positive to negative, as the pump Rabi frequency increases, is the open near-degenerate ${F}_{g}=\stackrel{\ensuremath{\rightarrow}}{1}{F}_{e}=1$ system. In the presence of Doppler broadening, the dispersion is positive for all realistic experimental parameters. Thus the switchover in the sign of the dispersion is only observable in the absence of Doppler broadening.