Multiple Fano resonances inspired by bound states in all-dielectric double-opening resonant ring metasurfaces

Abstract

Sensors are important tools in the fields of biology and chemistry. Highly sensitive, robust and low-cost sensors and their preparation methods have always constituted a research topic. In this paper, an all-dielectric metasurface with a double-opening resonant ring is proposed. The metasurfaces can support MD and ED modes to excite three q-BIC modes. And the Q-factor can reach 4.97×104, 2.02×105 and 1.39×106 respectively. For the asymmetric structure, the three excited peaks have certain polarization-insensitive characteristics. With the introduction of graphene, the dynamic regulation of transmission peak can be realized, specifically the regulation of resonance wavelength, and the intensity of transmittance. Since the all-dielectric metasurfaces assist in enhancing the interaction of the light field with dielectric materials, and the field enhancement effect is obvious, so we analyze the sensing properties of the metasurface. It has a sensitivity of up to 1340 nm/RIU and FOM can reach 1.17×106. Finally, we additionally analyze another asymmetric form, which enables the excitation of the q-BIC by changing the polarization angle, making the structure potentially valuable for optical switching as well.

Keywords

• All-dielectric metasurfaces
• Multipole decomposition
• Refractive index sensor
• Polarization insensitive