Engineering of spontaneous emission in free space via conditional measurements

TL;DR

This paper demonstrates how conditional measurements and dipole-dipole interactions among three atoms can be used to control and engineer spontaneous emission patterns in free space, revealing complex super- and subradiant behaviors.

Contribution

It introduces a novel approach combining conditional photon correlation measurements with dipole interactions to manipulate atomic emission properties.

Findings

Conditional measurements alter emission dynamics significantly.

Dipole-dipole interactions induce super- and subradiance.

Engineered emission patterns depend on measurement and atom configuration.

Abstract

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 sub-wavelength 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 differs strongly 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 to engineer the spontaneous emission in space and time.