Author:
Song Shaozhe,Yu Shilin,Li Hao,Zhao Tonggang
Abstract
Abstract
Fano resonance with high Q-factor plays a pivotal role in the field of optoelectronic applications, especially refractive index sensing. However, ultra-high Q-factor for metallic metasurfaces has been a challenge due to their great ohmic losses. Herein, we propose and numerically analyze an all-dielectric hollow metasurface in the near infrared region which consists of silicon cylinders with two asymmetric rectangular hollows. A sharp Fano resonance with modulation depth close to 100% excited by quasi-bound state in continuum, whose Q-factor can reach 8428 when
δ
= 40 nm. With the Cartesian multipole decomposition technique, the two excited Fano resonances can be characterized by toroidal dipole response and magnetic dipole (MD) response, respectively. It is worth noting that the Q-factor of MD mode can reach 17106. Moreover, the dependence of the transmission spectra on different geometric parameters is investigated as well. Due to their narrow linewidths and strong near-field confinement, the proposed structure can be applied to a refractive index sensor, yielding a maximum sensitivity (S) of 160 nm RIU−1 and a maximum figure of merit of 575 RIU−1. It is believed that the proposed structure can offer an excellent prospect for biomedical, agriculture, and chemical sensing applications.
Subject
Industrial and Manufacturing Engineering,Condensed Matter Physics,Instrumentation,Atomic and Molecular Physics, and Optics
Cited by
27 articles.
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