High-Q quasi-BIC in photonic crystal nanobeam for ultrahigh sensitivity refractive index sensing

Bing Duan; Songyi Liu; Xiao Liu; Xiao-chong Yu; Chuan Wang; Daquan Yang

Results in Physics (Apr 2023)

High-Q quasi-BIC in photonic crystal nanobeam for ultrahigh sensitivity refractive index sensing

Bing Duan,
Songyi Liu,
Xiao Liu,
Xiao-chong Yu,
Chuan Wang,
Daquan Yang

Affiliations

Bing Duan: State Key Laboratory of Information Photonics and Optical Communications, and School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
Songyi Liu: Guangxi Key Laboratory of Optoelectronic Information Processing, School of Optoelectronic Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Xiao Liu: State Key Laboratory of Information Photonics and Optical Communications, and School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
Xiao-chong Yu: Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
Chuan Wang: School of Artificial Intelligence, Beijing Normal University, Beijing 100875, China
Daquan Yang: State Key Laboratory of Information Photonics and Optical Communications, and School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China; School of Information Science and Technology, Tibet University, Lhasa 850000, China

Journal volume & issue: Vol. 47
p. 106304

Abstract

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We propose and numerically demonstrate the existence of bound state in the continuum (BIC) in silicon-based one-dimensional photonic crystal nanobeam (1D-PCN). The 1D-PCN is formed by introducing rectangular air nanoholes in a simple 1D nanobeam waveguide. By engineering the structure parameters, an ideal BIC with infinite quality (Q) factor is demonstrated in 1D-PCN. On this basis, we further investigate the refractive index sensing performance with quasi-BIC by introducing defects into the aforementioned 1D-PCN structure, and an ultrahigh Q factor of ∼ 4.1 × 107 is obtained. Compared to the conventional sensing mechanism based on the shift of forbidden bands modes, the 1D-PCN sensor based on quasi-BIC has a comparable figure of merit (FOM) higher than 106. It is worth mentioning that the quasi-BIC can be directly excited by external light sources without the special coupling mechanism, which provides a new method for ultrasensitive refractive index sensing.

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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