Space-time interference during the spontaneous emission of photons

Samad Roshan Entezar

The free space spontaneous emission spectra of a driven five-level atom embedded in a defective double-band photonic band-gap material are investigated. The effect of quantum interference on the spontaneous emission spectra and its nature are discussed. It is shown that the nature of quantum interference in the presence of the driving field and defect mode may be destructive or constructive depending on the initial atomic coherency.

Yu.L. Dobrynin, V. V. Lomonosov

Jorrit Visser, Gerard Nienhuis

Emmanuel Paspalakis, Christoph H. Keitel, P. L. Knight

We discuss the spontaneous emission from a coherently prepared and microwave-driven doublet of potentially closely spaced excited states to a common ground level. Multiple interference mechanisms are identified that may lead to fluorescence inhibition in well-separated regions of the spectrum or act jointly in canceling the spontaneous emission. In addition to phase-independent quantum interferences due to combined absorptions and emissions of driving field photons, we distinguish two competing phase-dependent interference mechanisms as means of controlling the fluorescence. The indistinguishable quantum paths may involve the spontaneous emission from the same state of the doublet, originating from the two different components of the initial coherent superposition. Alternatively the paths involve a different spontaneous photon from each of two decaying states, necessarily with the same polarization. This makes these photons indistinguishable in principle within the uncertainty of the two decay rates. The phase dependence arises for both mechanisms because the interfering paths differ by an unequal number of stimulated absorptions and emissions of the microwave field photons.

Manuel Bojer, Lukas Götzendörfer, Romain Bachelard +1 more

We study the collective spontaneous emission of three identical two-level atoms initially prepared in the excited states by measuring Glauber's third-order photon correlation function. Assuming two atoms at subwavelength distance from each other such that they are subject to the dipole-dipole interaction while the third one is located several wavelengths away, we observe super- and subradiant decay alike, depending on the direction of observation. Unlike the case where no remote atom is introduced or no conditional measurements are performed, the spontaneous emission behavior of the conditioned three-atom system is strongly modified, i.e., differing from the single-atom and the canonical two-atom configuration. The conditional measurements associated with the three-photon correlation function in combination with the dipole-dipole interaction between the adjacent atoms lead to quantum interference among the different decay channels allowing one to engineer the spontaneous emission in space and time.

P. E. Gordon, N. M. Chase