Theoretical analysis of the coherence-brightened laser in air
Luqi Yuan, Brett H. Hokr, Andrew J. Traverso, Dmitri V. Voronine, Yuri Rostovtsev, Alexei V. Sokolov, and Marlan O. Scully
Accepted
We present a detailed theoretical study of a recent experiment [A.J. Traverso et al. Proc. Natl. Acad. Sci. 109, 15185 (2012)], in which a laser-like source is created in air by pumping with a nanosecond pulse. The source generates radiation in forward as well as in backward directions. The temporal behavior of the emitted pulses is investigated for different pump shapes and durations. Our analysis indicates that the spiky emission is due to quantum coherence via cooperation between atoms of ensemble, which leads to strong-oscillatory superfluorescence. We have shown that these cooperative non-adiabatic coherence effects cannot be described by rate equations, and, instead, a full set of the Maxwell-Bloch equations must be used. We consider a range of parameters and study transitions between various regimes. Understanding these coherence-brightened processes in air should lead to improvements in environmental, atmospheric remote sensing and other applications.