Local Control of Two-Photon Absorption in a Six-Level Atomic System by Using a Coherent Perturbation Field

李院院, Jintao Bai, Li Li +2 more

Jia Wen-Zhi, Shun-Jin Wang

If a coherent perturbation field is used to couple the excited level of the coupling transition in the five-level K-type atom with another higher excited level, the two-photon electromagnetically induced transparency can be locally modulated by altering the parameters of the additional perturbation field. With different detunings of the coherent perturbation field, the absorption peak or transparency window with sharp and high-contrast spectral feature can be generated in the two-photon absorption spectrum. The physical interpretation of these phenomena is given in terms of the dressed states.

Saswata Ghosh, Swapan Mandal

The application of two coupling/pump fields to an M-type six-level atomic system in order to manipulate the probe response is suggested in this paper. With the inverted population condition the analytical formulation of the probe response is examined under the purview of coupling field-induced double-control quantum interference effects at different detunings. In particular, we report electromagnetically induced absorption and transparency via controlling the driving contribution of two coupling fields on different probe transitions. These driving contributions of the two coupling fields rely on lower-level hyperfine coherence, detuning and strength.

Gerard Nienhuis, F. Schuller

Ming-Chiang Li

Lei Zhang, Ge Yan, Zhang Xiang-Yang

A scheme of two-dimensional atomic localization of the Λ-type quasi-four-level atoms based on quantum-coherent-controlled absorption is proposed. Using the perturbation theory of the density matrix, the filter function is derived for the position probability distribution of atoms, which is determined by the imaginary part of the optical susceptibility. Because of the space-dependent interaction between atoms and fields, the position information is contained in the filter function, which provides an approach to explore the spacial position probability distribution of a single atom. Effect of the initial state of the atom under coherent control on the atomic localization is analyzed. It is found that the atomic localization is related to the initial atom distribution and the dipole moment between two lower levels under the coherent field control. When probing field and coupling field are under the configuration of the electromagnetically induced transparency, the position of atoms can be localized in the domain of sub wavelength; when the electromagnetically induced transparency is not satisfied, an atom can be measured in a sub wave region with the probability of 100% by changing the traveling wave amplitude in the controlling field and the detuning in the probing field.