Opt Express. 2023 Mar 13;31(6):10805-10819. doi: 10.1364/OE.485218.
In this paper, an all-dielectric metasurface consisting of a unit cell containing a nanocube array and organized periodically on a silicon dioxide substrate is designed and analyzed. By introducing asymmetric parameters that can excite the quasi-bound states in the continuum, three Fano resonances with high Q-factor and high modulation depth may be produced in the near-infrared range. Three Fano resonance peaks are excited by magnetic dipole and toroidal dipole, respectively, in conjunction with the distributive features of electromagnetism. The simulation results indicate that the discussed structure can be utilized as a refractive index sensor with a sensitivity of around 434 nm/RIU, a maximum Q factor of 3327, and a modulation depth equal to 100%. The proposed structure has been designed and experimentally investigated, and its maximum sensitivity is 227 nm/RIU. At the same time, the modulation depth of the resonance peak at λ = 1185.81 nm is nearly 100% when the polarization angle of the incident light is 0 °. Therefore, the suggested metasurface has applications in optical switches, nonlinear optics, and biological sensors.
本文设计并分析了一种由含有纳米立方体阵列的单元和周期性排列在二氧化硅衬底上的单元组成的全介质超表面。通过引入能够激发连续体中的准束缚态的非对称参数，可以在近红外产生三个具有高 Q 因子和高调制深度的 Fano 共振。三个 Fano 共振峰分别由磁偶极子和环形偶极子激发，结合了电磁的分布特征。模拟结果表明，所讨论的结构可用作折射率传感器，其灵敏度约为 434 nm/RIU，最大 Q 因子为 3327，调制深度等于 100%。已经设计并实验研究了该结构，其最大灵敏度为 227 nm/RIU。同时，当入射光的偏振角为 0°时，在 λ=1185.81 nm 处的共振峰的调制深度接近 100%。因此，所提出的超表面在光开关、非线性光学和生物传感器中有应用。
