Multiple high-Q Brillouin zone folding guided mode resonances in all-dielectric metasurfaces

High quality (Q) factors guided mode resonances (GMRs) are important platform for enhancing light–matter interactions. Conventional GMRs are excited by embedding periodic nanoholes in planar thin films, where the size of the holes determines the Q-factors. These control methods are relatively limited. In this work, we study multiple high-Q band folding GMRs in the near-infrared region and explore their sensing characteristics. By constructing a nanohole dimer metasurface, five band folding ultrahigh-Q GMRs are formed and corresponding high-Q GMRs are obtained by changing the size of one nanohole to break the mirror symmetry of the structure and thus manipulate the energy radiation of the modes. These resonance modes exhibit greater stability in momentum space, and their excitation is not strictly dependent on perpendicularly incident light, which facilitates experimental testing. We fabricate a series of samples to confirm these high-Q GMRs, with experimental Q-factors reaching 5.0 × 103. Next, we investigate the sensing characteristics of these GMRs, and due to the significant differences in their field distributions, TM0 mode has the best sensing performance among the five modes. Here, by spin-coating photoresists on the surface of the devices, we examine their sensing properties. It is proved that the specificity of the eigenfield localization of TM0 mode results in an excellent performance of the sensing properties of this mode, with an experimental sensitivity and figure of merit of 124 nm/RIU and 105, respectively. This work provides a route for the realization of metasurfaces with high Q-factors, which has potential applications in nanophotonics.