High-Q localized surface plasmon resonance based on bound states in the continuum for enhanced refractive index sensing

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)609-612
Journal / PublicationOptics Letters
Volume47
Issue number3
Online published25 Jan 2022
Publication statusPublished - 1 Feb 2022

Abstract

Nanophotonics based on localized surface plasmon resonance (LSPR) has emerged as a vibrant arena for research into enhanced light–matter interactions with potential applications in imaging, sensing, and computing. However, the low quality (Q) factor of LSPR is a significant barrier to comprehensive device applications. Here, we demonstrate that coupling the LSPR of a gold nanowire array with the optical bound states in the continuum (BIC) of a dielectric double-layer grating can significantly increase the Q factor of LSPR. We realize two hybrid modes with Q factors of up to 111 at 558 nm and 83 at 582 nm, which are about 14 and 10 times larger than those of an uncoupled gold nanowire array. Based on temporal coupled-mode theory, we further show that the resonance frequencies and Q factors of the hybrid modes can be modulated and optimized by varying relevant structural parameters. This coupled system provides a new platform for improving the figures of merit (FoMs) of LSPR-based refractive index sensors, and the concept of LSPR–BIC coupling can be extended to other similar nanosystems.

Citation Format(s)

High-Q localized surface plasmon resonance based on bound states in the continuum for enhanced refractive index sensing. / Chen, Haoran; Wang, Hongfei; Wong, Kwok-Yin et al.
In: Optics Letters, Vol. 47, No. 3, 01.02.2022, p. 609-612.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review