Positive-Pphase-space-method simulation of superradiant emission from a cascade atomic ensemble

Abstract

The superradiant emission properties from an atomic ensemble with cascade level configuration is numerically simulated. The correlated spontaneous emissions (signal then idler fields) are purely stochastic processes which are initiated by quantum fluctuations. We utilize the positive-P phase space method to investigate the dynamics of the atoms and counter-propagating emissions. The light field intensities are calculated, and the signal-idler correlation function is studied for different optical depths of the atomic ensemble. Shorter correlation time scale for a denser atomic ensemble implies a broader spectral window needed to store or retrieve the idler pulse.

Narrow Band Source of Transform-Limited Photon Pairs via Four-Wave Mixing in a Cold Atomic Ensemble

“…[37,38], the variation of the emitted bandwidth À due to collectively enhanced decay can be modeled with the relation À ¼ À 0 ð1 þ NÞ, with the natural linewidth À 0 ¼ 2 Â 5:8 MHz of the 5P 1=2 , [39], the atom number N, and a geometry factor . We also find a linear increase of À with OD m compatible with this model, since N is proportional to our measured OD m ; the solid line in Fig.…”

“…Bandwidth (FWHM) of heralded idler photons (pairs) for different cloud optical densities (OD m ) (filled circles). The line shows the theoretical model according to Refs [37,38]…”

Photon-Pair Generation from Chip-Scale Cs Atomic Vapor Cell

“…Figure 4 shows the heralding e ciency (red squares) as a function of OD under the conditions on the pump power of 0.5 mW and the coupling power of 5 mW. The decrease in the heralding e ciency at high OD can be explained by reabsorption of the idler photon in the medium, whereas the optimal OD for high heralding e ciency is explained by the enhancement in the collective emission into the phase-matched direction [40][41].…”

Polarization entanglement and quantum beats of photon pairs from four-wave mixing in a cold87Rb ensemble

“…The transition P F 5 , 3 3 2 = to S F 5 , 2 1 2 = is 2.8 times stronger than from P F 5 , 2 3 2 = [25]. This results in a higher optical density (OD) for the F 3 = transition [26], and should lead to a faster decay via path X [27]. To experimentally investigate this, we perform separate time correlation measurements between the detection of signal and idler photons for each decay path.…”