Fernández-Fernández D, González-Tudela A
Institute of Fundamental Physics IFF-CSIC, Calle Serrano 113b, 28006 Madrid, Spain.
Instituto de Ciencia de Materiales de Madrid ICMM-CSIC, 28049 Madrid, Spain.
Phys Rev Lett. 2022 Mar 18;128(11):113601. doi: 10.1103/PhysRevLett.128.113601.
Subwavelength atomic arrays, recently labeled as quantum metamaterials, have emerged as an exciting platform for obtaining novel quantum optical phenomena. The strong interference effects in these systems generate subradiant excitations that propagate through the atomic array with very long lifetimes. Here, we demonstrate that one can harness these excitations to obtain tunable directional emission patterns and collective dissipative couplings when placing judiciously additional atoms nearby the atomic array. For doing that, we first characterize the optimal square array geometry to obtain directional emission patterns. Then, we characterize the best atomic positions to couple efficiently to the subradiant metasurface excitations and provide several improvement strategies based on entangled atomic clusters or bilayers. Afterward, we also show how the directionality of the emission pattern can be controlled through the relative dipole orientation between the auxiliary atoms and the one of the array. Finally, we benchmark how these directional emission patterns translate into to collective, anisotropic dissipative couplings between the auxiliary atoms by studying the lifetime modification of atomic entangled states.
亚波长原子阵列，最近被称为量子超材料，已成为获得新型量子光学现象的一个令人兴奋的平台。这些系统中的强干涉效应产生亚辐射激发，其在原子阵列中传播时具有很长的寿命。在这里，我们证明，当在原子阵列附近明智地放置额外的原子时，可以利用这些激发来获得可调谐的定向发射模式和集体耗散耦合。为此，我们首先表征获得定向发射模式的最佳方形阵列几何结构。然后，我们表征与亚辐射超表面激发有效耦合的最佳原子位置，并基于纠缠原子簇或双层提供几种改进策略。之后，我们还展示了如何通过辅助原子与阵列中原子的相对偶极子取向来控制发射模式的方向性。最后，我们通过研究原子纠缠态的寿命修改，来衡量这些定向发射模式如何转化为辅助原子之间的集体、各向异性耗散耦合。
