Chiral Bound States in the Continuum in Plasmonic Metasurfaces

Bound states in the continuum (BICs) offer novel mechanisms to boost 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 significant hurdle that severely limits independent control CD Q-factors. Here, 3D plasmonic are numerically demonstrated overcome high-Q quasi-BIC resonances (Q ≈ 938) with strong (≈0.67) mid-infrared. These made integrated-resonance units consisting twisted vertical split-ring resonator (VSRR) wall. Importantly, this dissimilar dimer configuration unlocks new degree freedom decouple CD, is, can be relatively independently manipulated by height wall angle VSRR, respectively. results provide paradigms manipulate advanced chiroptical responses, various applications require enhanced light–matter interaction.