• Advanced Photonics
  • Vol. , Issue , ()
Xu Zhixia, Chang Jie, Tong Jinye, Sievenpiper Daniel F. , Cui Tiejun
Author Affiliations
  • Dalian Maritime University
  • University of California San Diego
  • Southeast University
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    Abstract

    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, leading to universal spin-momentum locking. Besides the development of experimental technology, the advantages and research status of spin-sorting waveguides are summarized, and perspectives on future research are presented to explore an avenue for designing controllable spin-sorting devices in the microwave band.
    Manuscript Accepted: Jun. 22, 2022
    Posted: Jun. 22, 2022
    DOI: AP