Chiral Bound States in the Continuum in Plasmonic Metasurfaces

Abstract Bound states in the continuum (BICs) offer novel mechanisms to boost the quality factor (Q‐factor) of resonances. Unfortunately, current studies on chiral BICs metasurfaces suffer from a fundamental trade‐off between Q‐factor and circular dichroism (CD), presenting a significant hurdle that severely limits the independent control between CD and Q‐factors. Here, 3D plasmonic metasurfaces are numerically demonstrated that overcome the trade‐off and offer high‐Q quasi‐BIC resonances (Q ≈ 938) with strong CD (≈0.67) in the mid‐infrared. These metasurfaces are made of integrated‐resonance units consisting of a twisted vertical split‐ring resonator (VSRR) and a wall. Importantly, this dissimilar dimer…

• CU
  City University of Hong Kong

  Awards: Project No. 9380131, 9380131
• NN
  National Natural Science Foundation of China

  Award: 12104296
• UG
  University Grants Committee

  Awards: 15303521, GRF Project: 15303521, AoE/P-502/20
• GS
  Guangdong Science and Technology Department

  Award: 2020B1515120073
• ST
  Science, Technology and Innovation Commission of Shenzhen Municipality

  Award: SGDX2019081623281169