PhotoniX, Volume. 2, Issue 1, 7(2021)

Displacement-mediated bound states in the continuum in all-dielectric superlattice metasurfaces

Tan Shi... Zi-Lan Deng*, Qing-An Tu, Yaoyu Cao and Xiangping Li |Show fewer author(s)
Author Affiliations
  • Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China
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    Bound states in the continuum (BICs) are localized states coexisting with extended waves inside the continuous spectrum range, which have infinite lifetimes without any radiation. To extract high-Q quasi-BIC resonances from the symmetry-protected BIC for practical applications, symmetry-breaking approaches are usually exploited, either by slightly breaking the excitation field symmetry or structure symmetry. Here, we introduce an all-dielectric superlattice metasurface that can symmetry-compatibly convert BIC states into high-Q quasi-BIC modes based on the guided-mode resonance coupling by relative displacement tuning. The metasurface is composed of a superlattice of multiple nanobeams, supporting both magnetic mode and toroidal mode with large tunability. Both modes can interact with the incident continuum by mediating the displacement between nanobeams, which empowers dual asymmetric Fano resonances with high Q-factors. The bandwidth of the toroidal mode under y-polarized incidences and that of the magnetic mode under x-polarized incidences can be readily tuned by the local displacement between nanobeams in each unit cell. Such displacement-mediated BIC resonance is promising for various applications such as bio-molecule sensing and low threshold lasing.

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    Tan Shi, Zi-Lan Deng, Qing-An Tu, Yaoyu Cao, Xiangping Li. Displacement-mediated bound states in the continuum in all-dielectric superlattice metasurfaces[J]. PhotoniX, 2021, 2(1): 7

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    Paper Information

    Category: Research Articles

    Received: Jan. 2, 2021

    Accepted: Apr. 15, 2021

    Published Online: Jul. 10, 2023

    The Author Email: Deng Zi-Lan (zilandeng@jnu.edu.cn)

    DOI:10.1186/s43074-021-00029-x

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