Quantum controllable optical selective resonant excitation in a dense medium

The role of the local-field effects on quantum control of optical selective excitation was investigated. It was shown that the local-field effects add important features to quantum control in a resonant process during the interaction between an ultrashort pulse and optically dense medium. It was found that the near dipole-dipole (NDD) interaction caused an inversion-dependent frequency shift of the individual atom resonance for a dense collection of two-level atoms. The results show that NDD interaction causes a coupling between the excited states, during the presence of coherent atomic excitations.