利用排布在人工表面等离激元传输线两侧的微结构谐振组实现了波导类电磁诱导透明（Electromagnetically Induced Transparency，EIT）效应，并基于此开发了结构紧凑的片上传感器。根据电场分布的特性，发现片上类EIT效应的传感工作机理主要是利用暗模谐振器内部的强局域化电场对周围介质的敏感程度，能够反映到EIT特征频率的偏移量和谐振幅度的变化。进一步地，详细仿真了待测物的折射率、正切损耗、厚度、半径等参数变化对EIT透明窗口的响应规律，发现该片上传感器在1.26~1.79折射率变化范围下的灵敏度可达1.12 GHz/RIU，传感品质因数值为5.45。实验中通过对三种食用油进行传感测量，验证了所提出的基于类EIT效应的片上传感器具有高灵敏度、无标记检测和实验灵活的特点。

Controlling energy flow in waveguides has attractive potential in integrated devices from radio frequencies to optical bands. Due to the spin-orbit coupling, the mirror symmetry will be broken, and the handedness of the near-field source will determine the direction of energy transport. Compared with well-established theories about spin-momentum locking, experimental visualization of unidirectional coupling is usually challenging due to the lack of generic chiral sources and the strict environmental requirement. In this work, we design a broadband near-field chiral source in the microwave band and discuss experimental details to visualize spin-momentum locking in three different metamaterial waveguides, including spoof surface plasmon polaritons, line waves, and valley topological insulators. The similarity of these edge waves relies on the abrupt sign change of intrinsic characteristics of two media across the interface. In addition to the development of experimental technology, the advantages and research status of interface waveguides are summarized, and perspectives on future research are presented to explore an avenue for designing controllable spin-sorting devices in the microwave band.

Glide symmetry, which is one kind of higher symmetry, is introduced in a special type of plasmonic metamaterial, the transmission lines (TLs) of spoof surface plasmon polaritons (SSPPs), in order to control the dispersion characteristics and modal fields of the SSPPs. We show that the glide-symmetric TL presents merged pass bands and mode degeneracy, which lead to broad working bandwidth and extremely low coupling between neighboring TLs. Dual-conductor SSPP TLs with and without glide symmetry are arranged in parallel as two channels with very deep subwavelength separation (e.g., λ₀ / 100 at 5 GHz) for the application of integrated circuits and systems. Mutual coupling between the hybrid channels is analyzed using coupled mode theory and characterized in terms of scattering parameters and near-field distributions. We demonstrate theoretically and experimentally that the hybrid TL array obtains significantly more suppressed crosstalk than the uniform array of two nonglide symmetric TLs. Hence, it is concluded that the glide symmetry can be adopted to flexibly design the propagation of SSPPs and benefit the development of highly compact plasmonic circuits.