Pennetta Riccardo, Blaha Martin, Johnson Aisling, Lechner Daniel, Schneeweiss Philipp, Volz Jürgen, Rauschenbeutel Arno
Department of Physics, Humboldt-Universität zu Berlin, 12489 Berlin, Germany.
Phys Rev Lett. 2022 Feb 18;128(7):073601. doi: 10.1103/PhysRevLett.128.073601.
We experimentally and theoretically investigate collective radiative effects in an ensemble of cold atoms coupled to a single-mode optical nanofiber. Our analysis unveils the microscopic dynamics of the system, showing that collective interactions between the atoms and a single guided photon gradually build up along the atomic array in the direction of propagation of light. These results are supported by time-resolved measurements of the light transmitted and reflected by the ensemble after excitation via nanofiber-guided laser pulses, whose rise and fall times are shorter than the atomic lifetime. Superradiant decays more than 1 order of magnitude faster than the single-atom free-space decay rate are observed for emission in the forward-propagating guided mode, while at the same time, no speed-up of the decay rate is measured in the backward direction. In addition, position-resolved measurements of the light that is transmitted past the atoms are performed by inserting the nanofiber-coupled atomic array in a 45-m-long fiber ring resonator, which allow us to experimentally reveal the progressive growth of the collective response of the atomic ensemble. Our results highlight the unique opportunities offered by nanophotonic cold atom systems for the experimental investigation of collective light-matter interaction.
我们通过实验和理论研究了与单模光学纳米纤维耦合的冷原子系综中的集体辐射效应。我们的分析揭示了系统的微观动力学，表明原子与单个导波光光子之间的集体相互作用沿光传播方向在原子阵列中逐渐增强。这些结果得到了通过纳米纤维引导的激光脉冲激发后，对系综透射和反射光的时间分辨测量的支持，其上升和下降时间短于原子寿命。对于向前传播的导模发射，观察到超辐射衰变比单原子自由空间衰变率快1个多数量级，而与此同时，在向后方向上未测量到衰变率的加速。此外，通过将纳米纤维耦合的原子阵列插入45米长的光纤环形谐振器中，对透过原子的光进行位置分辨测量，这使我们能够通过实验揭示原子系综集体响应的渐进增长。我们的结果突出了纳米光子冷原子系统为集体光与物质相互作用的实验研究提供的独特机遇。
