Metasurfaces with maximum chirality empowered by bound states in the continuum

Abstract

We demonstrate that rotationally symmetric chiral metasurfaces can support arbitrarily sharp resonances with the maximum optical chirality determined by precise shaping of bound states in the continuum (BICs). Being uncoupled from one circular polarisation of light and resonantly coupled to its counterpart, a metasurface hosting the chiral BIC resonance exhibits a narrow peak in the circular dichroism spectrum. We propose a realization of such chiral BIC metasurfaces based on pairs of dielectric bars and validate the concept of maximum chirality by numerical simulations

References in corpus (4)

• Extreme optical activity and circular dichroism of chiral metal hole arrays
• Chiral bound states in the continuum
• Causality relations for materials with strong artificial optical chirality
• Bound states with complex frequencies near the continuum on lossy periodic structures

Cited by in corpus (6)

• Bound states in the continuum in photonic structures
• Nonlinear chiral metaphotonics
• Spin-Orbit-Locking Chiral Bound States in the Continuum
• Extremely intrinsic chirality in two-dimensional planar waveguide grating induced by quasi-bound states in the continuum
• Broadband Parametric Downconversion as a Discrete-Continuum Fano Interaction
• Arbitrary Polarization-Independent Backscattering or Reflection by Rotationally-Symmetric Reciprocal Structures