Electromagnetically induced transparency and evolution of a twolevel system under a strong chaotic field
Abstract
The present paper treats the electromagnetically induced transparency (EIT), i.e., the absorption spectrum of a weak probe field, nearresonant to a material transition, in the presence of a strong amplitudephase fluctuating field which couples the upper level of the transition to another excited level. The coupling field is assumed to be chaotic (i.e., a complex Gaussian process with a Lorentzian spectrum) and so strong that the material relaxation and the detuning can be neglected. In addition, we consider the Fourier transform of the spectrum U¯_{aa}(t), which determines absorption of a probe field with a timedependent intensity. The quantity U¯_{aa}(t) equals a diagonal element of the average reduced evolution operator of the twolevel system (TLS), coupled by the strong field. As a starting point, we use the stationary, partially averaged stochastic Schrödinger equation, which has the form of a set of two secondorder differential equations. The theory is developed by combining analytical and numerical approaches. For the most important regime, when the rms Rabi frequency V_{0} is much greater than the couplingfield bandwidth ν, we obtain scaling relations for the EIT line shape and the TLS evolution. In particular, the absorption at the minimum (i.e., at the resonance frequency) scales as ν^{1/3}V^{4/3}_{0}, whereas the evolution function U¯_{aa}(t) performs damped oscillations with the decay rate on the order of (V^{2}_{0}ν)^{1/3}. These results differ significantly from those following from the uncorrelatedjump model. The results of this paper are shown to be applicable to more general models of amplitudephase fluctuations than the GaussianMarkovian chaotic field.
 Publication:

Physical Review A
 Pub Date:
 March 2001
 DOI:
 10.1103/PhysRevA.63.033810
 Bibcode:
 2001PhRvA..63c3810K
 Keywords:

 42.50.Gy;
 42.50.Md;
 42.60.Mi;
 42.62.Fi;
 Effects of atomic coherence on propagation absorption and amplification of light;
 electromagnetically induced transparency and absorption;
 Optical transient phenomena: quantum beats photon echo freeinduction decay dephasings and revivals optical nutation and selfinduced transparency;
 Dynamical laser instabilities;
 noisy laser behavior;
 Laser spectroscopy