Robust Fano resonance between mechanical first- and second-order topological states

Linyun Yang, Ying Wu*, Kaiping Yu*, Rui Zhao, Wei Wang, Bernard Bonello, Bahram Djafari-Rouhani

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

9 Citations (Scopus)


The Fano resonance, as a phenomenon of wave scattering, is based on the interaction between a “bright mode” and a “dark mode” giving rise to an asymmetric and ultrasharp spectral peak. However, the Fano resonant frequency is sensitive to structural imperfections such as defects or disorders, which will shift the resonant peak, or even damage the Fano line shape. Here, we harness the coupling between the first-order and the higher-order topological insulators to overcome this shortcoming. We construct a first-order topological edge state to serve as a bright mode, and a second-order topological corner state to be the dark mode using the same base configuration. As a result, a topological Fano resonance is expected to occur around the resonant frequency of the dark mode. The robustness of the Fano resonance is verified by deliberately introducing various types of imperfections into the system. Our findings may further enhance confidence in using the resonance such as acoustic switching, refractive index sensing, high quality factor filters, and accurate interferometers.

Original languageEnglish
Article number107768
JournalInternational Journal of Mechanical Sciences
Early online date27 Sept 2022
Publication statusPublished - Dec 2022

Scopus Subject Areas

  • Civil and Structural Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Aerospace Engineering
  • Ocean Engineering
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics

User-Defined Keywords

  • Fano resonance
  • Second order corner modes
  • Topological edge states
  • Ultrahigh Q factor


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