Dressed states for a two-level atom driven by a trichromatic field

Z. Ficek, JOSIP SEKE, Andrey Vladimirovich Soldatov +2 more

Z. Ficek, Terry Rudolph

We show that a dynamical suppression of spontaneous emission, predicted for a three-level atom [S.-Y. Zhu and M. O. Scully, Phys. Rev. Lett. 76, 388 (1996)] can occur in a two-level atom driven by a polychromatic field. We find that the quantum interference, responsible for the cancellation of spontaneous emission, appears between different channels of transitions among the dressed states of the driven atom. We discuss the effect for bichromatic and trichromatic (amplitude-modulated) fields and find that these two cases lead to the cancellation of spontaneous emission in different parts of the fluorescence spectrum. Our system has the advantage of being easily accessible by current experiments.

G. Compagno, Roberto Passante, Franco Persico

Hyun-Jae Kim, Jong Rak Park, Hai-Woong Lee

A semiclassical approach to the dressed-atom theory is presented in which dressed energies and states are determined from the solutions of the semiclassical coupled equations for the atomic probability amplitudes. The semiclassical approach has an advantage over the standard quantum-mechanical approach, especially when an atom interacting with a nonmonochromatic field is considered, because the standard approach requires diagonalization of an infinite-dimensional Hamiltonian matrix for an evaluation of dressed energies and states. Explicit expressions for dressed states of a two-level atom interacting with a resonant monochromatic, bichromatic, and trichromatic field are given.

G. S. Agarwal, R. Bullough, N. Nayak

S. F. Chien, Mohamed Ridza Wahiddin, Z. Ficek

The quantum trajectories method is illustrated for the resonance fluorescence of a two-level atom driven by a multichromatic field. We discuss the method for the time evolution of the fluorescence intensity in the presence of bichromatic and trichromatic driving fields. We consider the special case wherein one multichromatic field component is strong and resonant with the atomic transition whereas the other components are much weaker and arbitrarily detuned from the atomic resonance. We find that the phase-dependent modulations of the Rabi oscillations, recently observed experimentally [Q. Wu, D. J. Gauthier, and T. W. Mossberg, Phys. Rev. A 49, R1519 (1994)] for the special case when the weaker component of a bichromatic driving field is detuned from the atomic resonance by the strong-field Rabi frequency, appear also for detunings close to the subharmonics of the Rabi frequency. Furthermore, we show that for the atom initially prepared in one of the dressed states of the strong field component the modulations are not sensitive to the phase. We extend the calculations to the case of a trichromatic driving field and find that apart from the modulations of the amplitude there is a modulation of the frequency of the Rabi oscillations. Moreover, the time evolution of the fluorescence intensity depends on the phase regardless of the initial conditions and a phase-dependent suppression of the Rabi oscillations can be observed when the sideband fields are tuned to the subharmonics of the strong-field Rabi frequency.