All-dielectric metasurfaces are a versatile platform to investigate a host of unconventional physical scattering responses. Effects, including high absorption and Huygens’ surfaces, have been demonstrated; however, a more exotic materialization—termed bound states in the continuum (BSCs)—exists and consists of nonradiating localized waves that lie within the energy spectrum of the continuum. Here we experimentally demonstrate a dynamic BSC at terahertz frequencies that realizes a material-limited high-quality factor ($Q$) resonance $Q=8.7\times {10}^3$, which may be modified by over 2 orders of magnitude through photodoping with band gap light. We elucidate the nature of the BSC resonance, and our experimental results are well supported by eigenvalue and $S$-parameter simulations. The demonstrated system and underlying theory establish a path to realize extremely high-$Q$ dynamic resonances, which may be useful for detection of hazardous materials and frequency-diverse imaging.

中文翻译：

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连续体中的动态束缚态

全介电超表面是研究多种非常规物理散射响应的通用平台。已经证明了包括高吸收率和惠更斯表面在内的各种影响。但是，存在着更为奇特的物化（称为连续体中的束缚态），并由位于连续体能谱内的非辐射局域波组成。在这里，我们通过实验演示了在太赫兹频率下的动态BSC，该BSC实现了材料有限的高质量因子$问$）共振 $问=8.7\times {10}^3$可以通过带隙光的光掺杂将其修改超过2个数量级。我们阐明了BSC共振的性质，本征值和$\mathrm{小号}$参数模拟。久经考验的系统和基础理论为实现极高的$问$ 动态共振，这对于检测有害物质和分频成像可能很有用。