Switchable magnetic dipole assisted double QBICs in an asymmetry four-leaf clover-shaped Ge2Sb2Te5 metasurface

Rujun Zhou; Si Luo; Jingyi Tian; Yusheng Zhang; Chenning Tao; Qiang Ling; Daru Chen

Results in Physics (Sep 2023)

Switchable magnetic dipole assisted double QBICs in an asymmetry four-leaf clover-shaped Ge2Sb2Te5 metasurface

Rujun Zhou,
Si Luo,
Jingyi Tian,
Yusheng Zhang,
Chenning Tao,
Qiang Ling,
Daru Chen

Affiliations

Rujun Zhou: Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China; Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
Si Luo: Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China; Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China; Corresponding authors.
Jingyi Tian: Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore; Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
Yusheng Zhang: Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China; Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
Chenning Tao: Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China; Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
Qiang Ling: Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China; Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China
Daru Chen: Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China; Key Laboratory of Optical Information Detection and Display Technology of Zhejiang, Zhejiang Normal University, Jinhua 321004, China; Corresponding authors.

Journal volume & issue: Vol. 52
p. 106901

Abstract

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Dynamically tunable metasurface resonators with high Q factors and excellent sensing performance still lack research. This paper proposes a dual-band symmetry broken induced quasi bound state in the continuum (QBIC) sensor in the near-infrared region based on an asymmetric four-leaf clover-shaped Ge2Sb2Te5 (GST) metasurface. The high-quality transmission spectrum can be tuned by switching the GST crystalline state. Two QBIC magnetic dipole resonances are excited at the amorphous GST state, QBIC Ⅰ (intracavity MD mode) and QBIC Ⅱ (intercavity high-order MD mode). Based on theoretical simulation, the refractive index sensitivity of the QBIC Ⅱ mode (318.05 nm/RIU) is enhanced higher than twice of the QBIC Ⅰ mode (134.03 nm/RIU) owing to the unique electromagnetic field properties. The ultra-high Q factors generated by the two MD resonance modes are 1.1 × 105 (QBIC Ⅰ) and 1.71 × 105 (QBIC Ⅱ) respectively for a small perturbation of the air hole offset distance D = 5 nm. By discussing the effect of the main structure parameters and the analyte thickness on the sensitivity, the optimal parameters are determined. The two strong QBICs supported by the a-GST metasurface are stable when the air hole’s offset from the unit center is at different directions and distances, indicating a good tolerance to fabrication requirements. These results provide a competitive switchable dual-band QBIC metasurface sensor, providing a potential route for tunable metadevices for functional sensing and dynamic control over signals.

Published in Results in Physics

ISSN: 2211-3797 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Physics
Website: http://www.journals.elsevier.com/results-in-physics/

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