Darkening of a brightened atom and real energy level via field generated coherence

Abstract

In contrast to traditional spontaneous generated coherence (SGC), a field generated coherence (FGC)-based atomic scheme is presented for spontaneous emission cancellation. It is easy to achieve an externally controllable experimental and dipole-alignment-independent trapping condition in this four-field-driven five-level atomic system. Consequently, the decay from the central dressed bare energy state (real energy state) of the set of the three upper closely spaced hyperfine decaying energy states of the sodium D2 line is completely cancelled under the trapping condition, exhibiting the novel phenomenon of a darkened bare energy state. Along with this cancellation, effective manipulation and storage of an atomic population in various dressed states of this one-atom quantum system are also explored. Extending to an atomic system of simple probability loss, based on the sodium D1 line, the whole brightened atom can also be darkened under its dipole-alignment-independent trapping condition, representing another experimentally viable, novel and potentially useful phenomenon.