Population Dynamics of Atoms induced by Partially Coherent Laser Fields

Jun Chen, Liu Zheng-Dong, Zheng Jun +2 more

In this paper，we report the effects of vacuum-induced coherence in a laser-driven four-level atom consisting of three near-degenerate upper levels having an additional coherence term due to interaction with the vacuum of the radiation field. We show that such coherence preserves the electromagnetically induced transparency and optical bistability phenomena. The dynamical behavior of the population distribution via vacuum-induced coherence was also analyzed numerically.

S. Zielińska-Kaniasty

Sergey V. Prants

A. Peralta Conde, Леонід Петрович Яценко, Jens Klein +2 more

We present experimental data to demonstrate coherently driven population inversion by retroreflection-induced bichromatic adiabatic passage in metastable helium atoms. Complete and robust population transfer from an initial to a target state is induced by coherent interaction of the atoms in a supersonic beam with two counterpropagating and temporally delayed laser pulses of different intensities. The radiation fields intersect the atomic beam slightly tilted away from normal incidence, thereby inducing Doppler shifts of the atomic resonance between the initial and the target state. Thus the laser pulses produce a bichromatic field in the rest frame of each atom, which induces complete coherent population transfer by an adiabatic passage process.

Constantine Mavroyannis

Daba A. Radnatarov, Sergey Khripunov, Sergey M Kobtsev +5 more

We present a study of the identified for the first time effect of electromagnetically-induced transparency delay in Rb vapours on the atomic clock transition. The effect consists in the presence of a delay in the time of the maximal total transmission of atomic vapour relative to the moment when a two-photon resonance is reached as the frequency difference between two laser fields (FDLF) deviates around the clock transition frequency. It was found out that the delay is higher for higher frequencies of the FDLF modulation and is accompanied by substantial evolution of the width and shape of the coherent population trapping resonance.