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  • Letter
  • Open Access

Hybrid bound states in the continuum beyond the diffraction limit

Ji Tong Wang1,*,† and Nicolae C. Panoiu1,2,‡

  • 1Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
  • 2Wuzhen Laboratory, Jiaxing 314500, People's Republic of China

  • *Contact author: jitong.wang@alumni.ucl.ac.uk
  • †Present address: Emergent Photonics Research Centre, Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom.
  • ‡Contact author: n.panoiu@ucl.ac.uk
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Phys. Rev. B 114, L111414 – Published 27 August, 2026

DOI: https://doi.org/10.1103/3ym7-s255

Abstract

Bound states in the continuum (BICs) have greatly impacted our ability to manipulate light-matter interactions at the nanoscale. However, in periodic structures, BICs are typically realized below the diffraction limit, thus leaving a broad spectral domain largely unexplored. Here, we introduce another type of at-Γ BICs of photonic crystal (PhC) slabs supporting higher-diffraction orders, which we call hybrid BICs (h-BICs), whereby symmetry protection and parameter tuning are utilized to suppress light emission in the zeroth- and higher-diffraction orders, respectively. By tuning certain structural parameters of the PhC slab, we fully characterize the dynamics of the topological structure of these h-BICs, including the generation, merging, splitting, and annihilation of circularly polarized states. We further show that the relative amount of light radiated in the first-order diffraction channels can be effectively controlled by simply breaking the C4v symmetry of the PhC slab. Our findings reveal a versatile approach to realize different types of BICs above the diffraction limit, and could potentially inspire efforts toward the development of photonic nanodevices, such as multivortex-beam generators, frequency converters, and lasers.

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Outline

Information

Phys. Rev. B 114, L111414– Published 27 August, 2026
  • Received 2 January 2026
  • Revised 30 July 2026
  • Accepted 10 August 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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