论文标题
稀释原子云中的次级和额外屈从于额定级过渡
Subradiance and superradiance-to-subradiance transition in dilute atomic clouds
论文作者
论文摘要
我们在稀释的超低rubidium（rb）原子中实验研究次级，其中$nλ_a^3 \ 3 \大约10^{ - 2} $（$ n $：原子密度，$λ_a$兴奋波长）和恢复性的光学深度是Unity的顺序。我们表明，在强烈的激发方案中，次级时尺度取决于云的激发部分。即，到激发脉冲的强度。在这个制度中，衰减动力学非常复杂，没有一个衰减时间恒定。相反，衰减时间常数在动态过程中变化。具体而言，我们能够观察到超级对屈服过渡的特征。我。例如，最初的衰减速率比独立衰减（超级发射）快，而在以后的时间过渡到较慢（次级发射）。我们还讨论了一个理论模型，其数值结果与实验非常吻合。
We experimentally study subradiance in a dilute cloud of ultracold rubidium (Rb) atoms where $n λ_a^3 \approx 10^{-2}$ ($n$: atomic density, $λ_a$ excitation wavelength) and the on-resonance optical depth of the cloud is of order unity. We show that in the strong excitation regime, the subradiant time-scales depend on the excitation fraction of the cloud; i.e., to the intensity of the excitation pulse. In this regime, the decay dynamics are highly complicated and there is not a single decay time-constant. Instead, the decay time constant varies during the dynamics. Specifically, we were able to observe signatures of superradiant-to-subradiant transition; i. e., initially the decay rate is faster than independent decay (superradiant emission), while at later times it transitions to slower (subradiant emission). We also discuss a theoretical model whose numerical results are in good agreement with the experiments.
