Description
Chirality, fundamentally defined by a lack of mirror symmetry, manifests in light-matter interactions as optical chirality — a differential response to circularly polarized light. Metasurfaces offer an efficient, subwavelength platform for engineering these effects. We establish a definitive link between the structural geometry of a dielectric metasurface and its optical chirality across linear and nonlinear regimes.
To formalize this, we introduce a symmetry decision tree correlating a nanostructure's rotational order to allowed circular-dichroism channels and transmission/reflection rules. We rigorously distinguish three-dimensional (3D) chirality, driving co-polarized circular dichroism, from planar (2D) chirality, which governs cross-polarization conversion. We demonstrate that maximizing cross-conversion dichroism in planar-chiral structures strictly requires coupling at least two resonant modes of opposite parity, yielding a clear design principle.
Applying this framework, we validate our findings across multiple architectures. For 3D chirality, we demonstrate maximum co-polarized dichroism using free-standing PMMA-layered silicon membranes. We also showcase mid-infrared chiral encoding, multiplexing independent images directly into transmission and circular-dichroism responses. Ultimately, controlled symmetry breaking unlocks intrinsic chirality in achiral architectures, providing a symmetry-grounded route for designing resonant chiral metasurfaces [1-4].
Acknowledgements
We acknowledge all co-authors of the cited papers, especially I. Sinev, B. Kumar, and M. Gorkunov.
References
[1] I. Sinev et al., “Chirality encoding in resonant metasurfaces governed by lattice symmetries”, Nat. Commun. 16, 1 (2025).
[2] B. Kumar et al., “Maximal optical chirality via mode coupling in bilayer metasurfaces”, ACS Photonics 12, 6717 (2025).
[3] I. Toftul et al., “Optical chirality of membrane metasurfaces with broken in-plane symmetry”, arXiv:2606.05775 (2026).
[4] I. Toftul et al., “Chiral Dichroism in Resonant Metasurfaces with Monoclinic Lattices”, Phys. Rev. Lett. 133, 216901 (2024).
| I am the presenting author | Yes |
|---|