High Q-factor Mie lattice resonance generated from out-of-plane magnetic dipole in all-dielectric defected semi-cylinder metasurface array

Abstract Due to the weak far-field radiation and strong local field enhancement properties of Mie lattice resonances, transmission resonance with significant high Q factor is achieved which could be used in applications such as refractive index sensing, filtering and nano lasing. In this paper, we design an semi-cylinder with cuboid defect metasurface array working in the near-infrared, where a resonance with extremely narrow linewidth in transmission spectrum has been demonstrated at the wavelength of 870.9408 nm. The full width at half-maximum of the resonance is as narrow as 0.0032 nm with a corresponding Q factor of 272169. According to distributions of the electric field and displacement current, it is confirmed that the narrow linewidth resonance is generated from the Mie lattice resonance which is originated from the coupling between the out-of-plane magnetic dipole mode with Rayleigh Anomalous diffraction. It is further verified that the out-of-plane magnetic dipole mode is excited due to the induced defect in the semi-cylinder. When being applied in refractive sensing, a sensitivity and a figure of merit of 333 nm/RIU and 104063 RIU -1 are numerically achieved simultaneously. Our study here provide a new way for achieving resonances with high Q-factors.