Abstract

Symmetry-protected bound states in the continuum (SP-BICs) are one of the most intensively studied BICs. Typically, SP-BICs must be converted into quasi-BICs (QBICs) by breaking the unit cell’s symmetry so that they can be accessed by the external excitation. The symmetry-broken usually results in a varied resonance wavelength of QBICs which are also highly sensitive to the asymmetry parameters. In this work, we demonstrate that QBICs with a stable resonance wavelength can be realized by breaking translational symmetry in an all-dielectric metasurface. The unit cell of metasurface is made of a silicon nanodisk dimer. The Q-factor of QBICs is precisely tuned by changing the interspacing of two nanodisks while their resonance wavelength is quite stable against the interspacing. We also find that such BICs show weak dependence on the shape of the nanodisk. Multiple decompositions indicate that the toroidal dipole dominates this type of QBIC. The resonance wavelengths of QBICs can be tuned only by changing either the lattice constants or the radius of nanodisk. Finally, we present experimental demonstrations on such a QBIC with a stable resonance wavelength. The highest measured Q-factor of QBICs is >3000. Our results may find promising applications in enhancing light–matter interaction.

Details

Title
Quasi-bound states in the continuum with a stable resonance wavelength in dimer dielectric metasurfaces
Author
You, Shaojun 1 ; Zhou, Mimi 2 ; Xu, Lei 3 ; Chen, Deliang 4 ; Fan, Menghui 2 ; Huang, Jing 2 ; Ma, Wenbin 2 ; Luo, Shengyun 5 ; Rahmani, Mohsen 3 ; Zhou, Chaobiao 2 ; Miroshnichenko, Andrey E 6 ; Huang, Lujun 7 

 School of Physics and Mechatronic Engineering, Guizhou Minzu University, Guiyang 550025, China; School of Chemical Engineering, Guizhou Minzu University, Guiyang 550025, China 
 School of Physics and Mechatronic Engineering, Guizhou Minzu University, Guiyang 550025, China 
 Advanced Optics and Photonics Laboratory, Department of Engineering, School of Science Technology, Nottingham Trent University, Nottingham NG11 8NS, UK 
 School of Physics and Electronic Science, Guizhou Education University, Guiyang 550025, China 
 School of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China 
 School of Engineering and Information Technology, University of New South Wales at Canberra, Northcott Drive, Canberra, ACT 2610, Australia 
 The Extreme Optoelectromechanics Laboratory (XXL), School of Physics and Electronic Sciences, East China Normal University, Shanghai 200241, China 
Pages
2051-2060
Publication year
2023
Publication date
2023
Publisher
Walter de Gruyter GmbH
ISSN
21928606
e-ISSN
21928614
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2814705302
Copyright
© 2023. This work is published under http://creativecommons.org/licenses/by/4.0 (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.