Strong correlation and anticorrelation via quantum coherence in a cascade atom with split metastable states

摘要

We show that strongly correlated and anticorrelated photons can be produced from two fluorescent fields emitted by a driven cascade atom with split metastable states. Depending on the choice of parameters, we have strong correlations for both fluorescent fields, anticorrelations for both, and strong correlation for one and anticorrelation for the other. In the presence of level splitting, we have two interfering cascade-dressed transitions from the top state to the antisymmetric superposition of the metastable states. The interference between the two cascade-dressed transitions is responsible for the strong correlations and anticorrelations.