Liberal Iñigo, Lobet Michaël, Li Yue, Engheta Nader
Electrical and Electronic Engineering Department, Universidad Pública de Navarra, Pamplona 31006, Spain;
Institute of Smart Cities, Universidad Pública de Navarra, Pamplona 31006, Spain.
Proc Natl Acad Sci U S A. 2020 Sep 29;117(39):24050-24054. doi: 10.1073/pnas.2008143117. Epub 2020 Sep 10.
Near-zero-index (NZI) supercoupling, the transmission of electromagnetic waves inside a waveguide irrespective of its shape, is a counterintuitive wave effect that finds applications in optical interconnects and engineering light-matter interactions. However, there is a limited knowledge on the local properties of the electromagnetic power flow associated with supercoupling phenomena. Here, we theoretically demonstrate that the power flow in two-dimensional (2D) NZI media is fully analogous to that of an ideal fluid. This result opens an interesting connection between NZI electrodynamics and fluid dynamics. This connection is used to explain the robustness of supercoupling against any geometrical deformation, to enable the analysis of the electromagnetic power flow around complex geometries, and to examine the power flow when the medium is doped with dielectric particles. Finally, electromagnetic ideal fluids where the turbulence is intrinsically inhibited might offer interesting technological possibilities, e.g., in the design of optical forces and for optical systems operating under extreme mechanical conditions.
近零折射率（NZI）超耦合，即电磁波在波导内的传播与其形状无关，是一种违反直觉的波动效应，在光互连和工程光与物质相互作用中有着应用。然而，对于与超耦合现象相关的电磁功率流的局部特性，人们了解有限。在此，我们从理论上证明二维（2D）NZI介质中的功率流与理想流体的功率流完全类似。这一结果揭示了NZI电动力学与流体动力学之间的有趣联系。这种联系被用于解释超耦合对任何几何变形的鲁棒性，以便分析复杂几何结构周围的电磁功率流，并研究介质掺杂介电粒子时的功率流。最后，湍流本质上受到抑制的电磁理想流体可能会带来有趣的技术可能性，例如在光力设计以及在极端机械条件下运行的光学系统方面。
