“Push- und Pullmarketing” in Online-Medien

Electromagnetically induced transparency with degenerate atomic levels

“…For the atoms at initially equilibrium state and with the fixed values of the level angular momenta the relative difference in the group velocities ε depends only on the ellipticity parameter α of the coupling field. An example of such dependence for the levels with the angular momenta J a = J c = 1, J b = 2, employed in the experiment [13], is presented in the Figure 8. The maximum difference in the group velocities ε = 0.625 is obtained with the circularly polarized coupling field (α = 0, π/2), while the minimum difference ε = 0.125 is obtained with the linearly polarized coupling field (α = π/4).…”

“…In the case of linearly polarized coupling field the polarization component with the smaller group velocity is linearly polarized in same direction as the coupling field, while the polarization component with the larger group velocity is linearly polarized in the direction perpendicular to that of the coupling field. In the experiment [13] the coupling field was linearly polarized in the direction of propagation of the probe field: l cq = δ q,0 (π-polarized), while it propagated in the perpendicular direction, and the atoms were prepared at the pure Zeeman state |J a = 1, m a = 0 > with the zero projection on the quantization axis. Under such conditions we obtain for the tensor (23): a jk = 1.667δ jk , so that the group velocity of the probe pulse in this case does not depend on its polarization.…”

“…Generally the atoms are at the equilibrium ground state with equally populated Zeeman sublevels, however they may be prepared at some special state [13].…”

“…Such memory based on the controlled adiabatic deceleration and acceleration of single-photon pulses in the resonant media was suggested in [9,10], and soon the possibility of storage of light pulses was realized in rubidium vapor in the experiment [11]. The recent experiments [12,13,14] on EIT-based quantum memory demonstrate the continuously improving efficiency and fidelity. There are different ways to encode the single-photon qubit, for example, in two spectral components of the photon pulse, as it was recently proposed in [15], but the most natural way for qubit encoding is provided by the photon two polarization degrees of freedom, as it was implemented in the experiments [12,13].…”

“…The recent experiments [12,13,14] on EIT-based quantum memory demonstrate the continuously improving efficiency and fidelity. There are different ways to encode the single-photon qubit, for example, in two spectral components of the photon pulse, as it was recently proposed in [15], but the most natural way for qubit encoding is provided by the photon two polarization degrees of freedom, as it was implemented in the experiments [12,13]. To store the photon polarization qubit its both polarization components must be effectively stopped in the medium, however the group velocities of these two components may differ essentially due to the optical anisotropy induced by the polarization of the coupling field.…”