Ruks L, Ballantine K E, Ruostekoski J
NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa, 243-0198, Japan.
NTT Research Center for Theoretical Quantum Information, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa, 243-0198, Japan.
Nat Commun. 2025 Feb 12;16(1):1433. doi: 10.1038/s41467-025-56250-w.
The quest to manipulate light propagation in ways not possible with natural media has driven the development of artificially structured metamaterials. One of the most striking effects is negative refraction, where the light beam deflects away from the boundary normal. However, due to material characteristics, the applications of this phenomenon, such as lensing that surpasses the diffraction limit, have been constrained. Here, we demonstrate negative refraction of light in an atomic medium without the use of artificial metamaterials, employing essentially exact simulations of light propagation. High transmission negative refraction is achieved in atomic arrays for different level structures and lattice constants, within the scope of currently realised experimental systems. We introduce an intuitive description of negative refraction based on collective excitation bands, whose transverse group velocities are antiparallel to the excitation quasi-momenta. We also illustrate how this phenomenon is robust to lattice imperfections and can be significantly enhanced through subradiance.
通过自然介质无法实现的方式来操控光传播的探索推动了人工结构化超材料的发展。最显著的效应之一是负折射，即光束偏离边界法线方向。然而，由于材料特性，这种现象的应用，如超越衍射极限的透镜效应，受到了限制。在此，我们展示了在不使用人工超材料的原子介质中光的负折射现象，采用了光传播的基本精确模拟。在当前已实现的实验系统范围内，针对不同的能级结构和晶格常数，在原子阵列中实现了高透射率的负折射。我们基于集体激发带引入了一种直观的负折射描述，其横向群速度与激发准动量反平行。我们还说明了这种现象对晶格缺陷具有鲁棒性，并且可以通过亚辐射显著增强。
