Atomic systems probe absorption interference

This can be explained from our four-level atomic system model when the additional perturbation field is added, there exist two dark states, and their mutual interference can induce a sharp light absorption [39]. In the case aroimd the three-photon resonanee, the two dark-state resonanees play nearly equal roles and their interference induces the occurrence of three sharp peaks of atom localization in the subwavelength domain. When the probe-field detuning is large, the role of one... 

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