Whispering-gallery modes (WGMs), confining the resonant photons in nanoscale volumes, have been known to exhibit high-quality factor and sensitivity for electromagnetic waves in the field of nanophotonics. Here, we numerically demonstrate that a metasurface, which consists of periodic arrays with concentrically hybrid rectangular-slot (RS) and circular-ring-aperture (CRA) unit cells, supports polarization-dependent plasmonic sensing and switching in the visible and near-infrared regions. In particular, it is shown that the magnetic plasmon-induced transparency (PIT) effect arises from the coupling between a wideband WGM resonance and a narrowband magnetic dipole resonance mode in the hybrid metasurface. It is of great interest to find that the resonance mode broadening and mode shift sensing can be realized by varying the polarization angle of incident light and the length of the RS structure, respectively. Moreover, a novel and easy-fabricated plasmonic switching can be implemented in the visible and near-infrared regions. By changing the inner radius of the CRA structure, we reveal that the operating wavelength of the plasmonic switching can be extended to the telecom O- or E-band with an optimal ON/OFF ratio being 18.35 dB. Our results provide a path toward designing compact and tunable PIT device and could expand the application range of subwavelength nanostructures to the realm of optical communications and information process.

中文翻译：

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Whispering-gallery模式共振辅助等离子体传感和亚波长纳米结构切换

众所周知，回音廊模式 (WGM) 将谐振光子限制在纳米级体积中，在纳米光子学领域对电磁波表现出高质量因子和灵敏度。在这里，我们通过数值证明了由具有同心混合矩形槽 (RS) 和圆环孔径 (CRA) 晶胞的周期性阵列组成的超表面支持偏振相关等离子体传感和可见光和近红外光切换地区。特别是，研究表明，磁等离子体诱导透明 (PIT) 效应源于混合超表面中宽带 WGM 共振和窄带磁偶极子共振模式之间的耦合。发现可以分别通过改变入射光的偏振角和 RS 结构的长度来实现谐振模式展宽和模式偏移传感，这是非常有趣的。此外，可以在可见光和近红外区域实现一种新颖且易于制造的等离子体开关。通过改变 CRA 结构的内半径，我们发现等离子体开关的工作波长可以扩展到电信 O 或 E 波段，最佳开/关比为 18.35 dB。我们的研究结果为设计紧凑且可调谐的 PIT 器件提供了一条途径，并且可以将亚波长纳米结构的应用范围扩展到光通信和信息处理领域。一种新颖且易于制造的等离子体开关可以在可见光和近红外区域实现。通过改变 CRA 结构的内半径，我们发现等离子体开关的工作波长可以扩展到电信 O 或 E 波段，最佳开/关比为 18.35 dB。我们的研究结果为设计紧凑且可调谐的 PIT 设备提供了一条途径，并且可以将亚波长纳米结构的应用范围扩展到光通信和信息处理领域。一种新颖且易于制造的等离子体开关可以在可见光和近红外区域实现。通过改变 CRA 结构的内半径，我们发现等离子体开关的工作波长可以扩展到电信 O 或 E 波段，最佳开/关比为 18.35 dB。我们的研究结果为设计紧凑且可调谐的 PIT 设备提供了一条途径，并且可以将亚波长纳米结构的应用范围扩展到光通信和信息处理领域。