Possessing fantastic abilities to freely manipulate electromagnetic waves on an ultrathin platform, metasurfaces have aroused intense interest in the academic circle. In this work, we present a high-sensitivity refractive index sensor excited by the guided mode of a two-dimensional periodic TiO₂ dielectric grating structure. Numerical simulation results show that the optimized nanosensor can excite guided-mode resonance with an ultra-narrow linewidth of 0.19 nm. When the thickness of the biological layer is 20 nm, the sensitivity, Q factor, and FOM values of the nanosensor can reach 82.29 nm RIU⁻¹, 3207.9, and 433.1, respectively. In addition, the device shows insensitivity to polarization and good tolerance to the angle of incident light. This demonstrates that the utilization of low-loss all-dielectric metasurfaces is an effective way to achieve ultra-sensitive biosensor detection.

中文翻译：

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基于全电介质超表面的高 Q 折射率传感器

超表面具有在超薄平台上自由操纵电磁波的奇妙能力，引起了学术界的浓厚兴趣。在这项工作中，我们提出了一种由二维周期性 TiO ₂介电光栅结构的导模激发的高灵敏度折射率传感器。数值模拟结果表明，优化后的纳米传感器可以激发导模共振，具有0.19 nm的超窄线宽。当生物层厚度为20 nm时，纳米传感器的灵敏度、Q因子和FOM值可以达到82.29 nm RIU ^-1、3207.9 和 433.1。此外，该器件对偏振不敏感，对入射光角度具有良好的耐受性。这表明利用低损耗全电介质超表面是实现超灵敏生物传感器检测的有效途径。