Quantum-mechanical interference effects in the spontaneous-emission spectrum of a driven atom

Shi Yao ZHU*, Lorenzo M. Narducci, Marlan O. Scully

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

194 Citations (Scopus)


We study the influence of quantum interference on the spontaneous emission from an excited two-level atom when either the atomic upper or lower level is coupled by a coherent field to a third, usually higher-lying, state. In the case of the upper level coupling, destructive quantum interference between two competing decay amplitudes produces a dark line in the emission spectrum, a phenomenon that should not be confused with the well known population trapping, and a narrowing of one of the two side lobes that make up the spectral profile. Quantum interference is absent, instead, in the case of the lower level coupling, and the spectrum modified by the external driving field is just the incoherent superposition of two Lorentzian lines. We suggest a physical interpretation of these results. In addition, we compare the analytic predictions of the simplest nontrivial versions of these models with more realistic but nonanalytic descriptions and show, numerically, that the interference effects persist in the upper level case even when additional complications are taken into account.

Original languageEnglish
Pages (from-to)4791-4802
Number of pages12
JournalPhysical Review A
Issue number6
Publication statusPublished - 1995

Scopus Subject Areas

  • Atomic and Molecular Physics, and Optics


Dive into the research topics of 'Quantum-mechanical interference effects in the spontaneous-emission spectrum of a driven atom'. Together they form a unique fingerprint.

Cite this