High‐Q and Strong Chiroptical Responses in Planar Metasurfaces Empowered by Mie Surface Lattice Resonances

Abstract

Planar chiral metasurfaces have emerged as a versatile platform for manipulating chiral light‐matter interactions in diverse applications. However, it remains challenging to achieve high quality factors together with strong chirality. Here, chiral all‐dielectric metasurfaces with a high Q factor of 1220 and relatively large planar chirality of circular dichroism −0.37 under normal incidence, or with a high Q factor of 872 and large extrinsic 3D chirality of circular dichroism 0.7, based on Mie surface lattice resonances (SLRs) are proposed and experimentally demonstrated. Both SLR‐induced planar chirality under normal incidence and SLR‐assisted extrinsic 3D chirality under oblique incidence are achieved by perturbing the square lattice and by slightly tilting the incidence angle, respectively. It shows that the high‐Q and strong chirality arises from the different excitation efficiencies of Mie SLRs under the incidences of left‐ and right‐handed circularly polarized light. With these findings, this study provides a new direction for realizing high‐performance chiral metasurfaces and holds great promise for chiral nanophotonic applications in biochemical sensing, emission or lasing, and nonlinear optics.

Automatically Aligned and Environment-Friendly Twisted Stacking Terahertz Chiral Metasurface with Giant Circular Dichroism for Rapid Biosensing

“…However, enhancement still needs to be improved. Metasurfaces with bound states in the continuum (BIC) emerged recently as a new strategy to provide giant CD in the single-layer scheme, , the extremely small slant angles or the dimensional accuracy required are quite challenging for fabrication . Sometimes, the CD is still not large enough, which needs the help of plasmonic enhancement by metallic nanoparticles. , Twisted stacking chiral metasurface is another potential way. , With the introduction of 3D out-of-plane mirror symmetry-breaking, a coupled mode of superchiral field could be implemented.…”

Crafting chirality in three dimensions via a novel fabrication technique for bound states in the continuum metasurfaces

“…However, most qBIC metasurfaces realized by breaking the symmetry of resonator geometry are constrained to two-dimensional manipulations (Fig. 1a ), a consequence of the limitations of fabrication techniques available for all-dielectric metasurfaces 5 , 10 , 14 – 16 . All fabrication techniques must build resonators that are smaller than the operational wavelength 17 .…”