Robust chirality via merging accidental BICs with net zero topological charge

Hui Hu; Chaobiao Zhou; Yukang Zhang; Meng-Xia Hu; Juntian Peng; Huawei Tang; Lujun Huang; Jianlong Liu; Chunying Guan; Zheng Zhu; Xiaoshuang Chen; Wei Lu; Xiangping Li; Zi-Lan Deng; Guanhai Li; Jinhui Shi; Cheng-Wei Qiu

doi:10.1186/s43593-026-00126-z

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Robust chirality via merging accidental BICs with net zero topological charge

eLight 2026年6卷

Research Article | Updated：2026-07-21

- Robust chirality via merging accidental BICs with net zero topological charge
- Robust chirality via merging accidental BICs with net zero topological charge
- Affiliations：
- Author bio：
- Funds：
  
  National Key Research and Development Program of China;Strategic Priority Research Program (B) of Chinese Academy of Sciences;National Natural Science Foundation of China;Fundamental Research Funds for Central Universities of the Central South University;Fundamental Research Funds for the Central Universities;Shanghai Science and Technology Committee;Shanghai Municipal Science and Technology Major Project;Guangdong Provincial Quantum Science Strategic Initiative;Guangdong Basic and Applied Basic Research Foundation;Guangzhou Science and Technology Program;Science and Technology Innovation Team Project of Guizhou Colleges and Universities;Natural Science Foundation of Guizhou Province;financial support by the Ministry of Education, Republic of Singapore;Competitive Research Program Award
- DOI：10.1186/s43593-026-00126-z
  中图分类号：
- 收稿：2025-10-25，
  
  修回：2026-01-29，
  
  录用：2026-02-04，
  
  网络首发：2026-03-19，
  
  纸质出版：2026-12
- Accepted：
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Hui Hu, Chaobiao Zhou, Yukang Zhang, 等. Robust chirality via merging accidental BICs with net zero topological charge[J]. eLight, 2026,6.

Hui Hu, Chaobiao Zhou, Yukang Zhang, et al. Robust chirality via merging accidental BICs with net zero topological charge[J]. eLight, 2026, 6.
Hui Hu, Chaobiao Zhou, Yukang Zhang, 等. Robust chirality via merging accidental BICs with net zero topological charge[J]. eLight, 2026,6. DOI： 10.1186/s43593-026-00126-z.

Hui Hu, Chaobiao Zhou, Yukang Zhang, et al. Robust chirality via merging accidental BICs with net zero topological charge[J]. eLight, 2026, 6. DOI： 10.1186/s43593-026-00126-z.

摘要

Abstract

Chiral metasurfaces leveraging bound states in the continuum (BICs) offer a powerful route for enhancing light–matter interactions. However

existing quasi-BIC architectures typically face a fundamental

trade-off between high quality (Q) factors and wide-angle chiral operation. Most designs confine strong circular dichroism (CD) to isolated points in momentum space (k-space) and often rely on intricate three-dimensional (3D) meta-atoms

rendering them highly sensitive to fabrication imperfections and angular misalignment. Here

we experimentally realize a planar dielectric metasurface that supports a wide k-domain chirality arising from accidental BICs with a net zero-topological-charge (ZTC). By lifting a Dirac-type degeneracy through controlled in-plane and out-of-plane symmetry breaking

we induce a deterministic topological evolution in which the same-handed circularly polarized (C) points migrate toward and accumulate near the Γ point

while the opposite-handed singularities annihilate or shift to higher k-space. This mechanism delivers record-level performance—an ultrahigh Q-factor (~ 10

)

near-unity linear and nonlinear CD (0.99/0.999)

and robust angular coverage (|

/2π

/2π|

0.06)—all within a fabrication-friendly

single-layer dielectric platform. These results establish a new regime for chiral photonics

unifying high chiral purity

angular robustness

and topological stability in a scalable planar architecture.

关键词

Keywords

references

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Publisher Correction: Robust chirality via merging accidental BICs with net zero topological charge