Schnitzer O, Brandão R
Department of Mathematics, Imperial College London, 180 Queen's Gate, London SW7 2AZ, UK.
Philos Trans A Math Phys Eng Sci. 2022 Sep 5;380(2231):20210399. doi: 10.1098/rsta.2021.0399. Epub 2022 Jul 18.
Metasurfaces formed of arrays of subwavelength resonators are often tuned to 'critically couple' with incident radiation, so that at resonance dissipative and radiative damping are balanced and absorption is maximized. Such design criteria are typically derived assuming an infinite metasurface, whereas the absorption characteristics of finite metasurfaces, even very large ones, can be markedly different in certain frequency intervals. This is due to the excitation of surface waves, intrinsic to resonant metasurfaces and especially meta-resonances, namely collective resonances where the surface waves form standing-wave patterns over the planar metasurface domain. We illustrate this issue using a detailed model of a Helmholtz-type acoustic metasurface formed of cavity-neck pairs embedded into a rigid substrate, with geometric and dissipation effects included from first principles (R. Brandão and O. Schnitzer, Wave Motion, , 102583, 2020). This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 1)'.
由亚波长谐振器阵列构成的超表面通常被调谐到与入射辐射“临界耦合”，从而在共振时耗散阻尼和辐射阻尼达到平衡，吸收最大化。此类设计标准通常是在假设超表面无限大的情况下推导得出的，而有限超表面，即便尺寸非常大，其吸收特性在某些频率区间可能会有显著差异。这是由于表面波的激发，表面波是谐振超表面尤其是元共振所固有的，元共振即集体共振，此时表面波在平面超表面区域形成驻波模式。我们使用一个详细模型来说明这个问题，该模型是一个由嵌入刚性基底的腔颈对构成的亥姆霍兹型声学超表面，其中几何和耗散效应从第一性原理出发进行考虑（R. 布兰当和O. 施尼策，《波动》，第 102583 期，2020 年）。本文是主题为“多尺度复杂介质和结构化超材料中的波产生与传输（第 1 部分）”的特刊的一部分。
