Ultra-High Quality Factor Resonances in a Pinwheel-Shaped All-Dielectric Metasurface Based on Bound States in the Continuum

Abstract

Combining with the bound states in the continuum (BICs) theory in all-dielectric metasurfaces has become an extensively used method to excite multiple high quality(Q) factor Fano resonances, which remarkably enhance the performance of structures to be applied to refractive index sensors. In this paper, a novel silicon pinwheel-shaped all-dielectric metasurface in the near-infrared region is designed and numerically investigated. Two Fano resonances are excited in the original structures. After breaking the symmetry of the original structures in combination with the BIC theory, four sharp Fano resonances are excited and the maximum Q-factor exceeds 3.9 × 10 5 when δ = 10 nm. With the asymmetric parameter δ = 80 nm, multiple Fano resonances could be turned on and off by turning the polarization of the incident light, which performs excellent characteristics in optical switches. Both in the original structures and in the asymmetric state it offers outstanding sensing characteristics. Furthermore, with δ = 80 nm and the polarization angle 90 degrees, the sensitivity and the figure of merit (FOM) could respectively reach up to 355 nm/RIU and 1375.97 RIU -1 . The designed structures may provide a way to enhance the performance of bio-chemical sensors, optical switches, and nonlinear optics.

Multi-function sensing applications based on high Q-factor multi-Fano resonances in an all-dielectric metastructure

“…To evaluate the performance of refractive index sensor, the two main performance indicators which include the sensitivity ( S ) and the figure of merit ( FOM ) are analyzed. Here, S is given by [ 17 ]: where is the offset of resonant wavelength and is the variation of refractive index. The FOM can be obtained using [ 17 ]: Where FWHM represents the full-width at half-maximum of Fano resonance.…”

“…Here, S is given by [ 17 ]: where is the offset of resonant wavelength and is the variation of refractive index. The FOM can be obtained using [ 17 ]: Where FWHM represents the full-width at half-maximum of Fano resonance.…”

Hollow Mie resonators based on toroidal magnetic dipole mode with enhanced sensitivity in refractometric sensing

“…431 (Sim.) Bound states in the continuum 29) 2023 the symmetry of metasurfaces, we find that the FOM of the hollow Mie resonators based on the non-radiative TMD mode is as high as 1389 RIU −1 , which is 92 times greater than that of the MD mode-based metasurfaces (15 RIU −1 ). The FOM of the proposed hollow Mie resonators is also greater than that of the BIC-based metasurfaces.…”

High Circular Dichroism Chiral Sensor Based on the Combination of Nanorods and Annular Cylinders

“…Moreover, the geometric shapes of chiral metasurfaces can be arbitrarily controlled, and their optical responses can be tailored by adjusting the structural parameters of the chiral metamaterial. This presents a wide range of applications in various fields, indicating promising prospects for the development of chiral metasurfaces [9][10]. In 2023, Hwaseob Lee demonstrated that a Mie-resonant metamaterial resonator, composed of a symmetrical and asymmetrical Mie scatterer pair, could reach exceptional points or chosen chirality while efficiently suppressing backscattering [11].…”