In this paper, we investigate a new, to the best of our knowledge, type of guided-mode resonance optical filter with polarization-independence at normal incidence and relatively narrow spectral linewidth in the near-infrared regime. The new optical spectral filter consists of a 2D array of silicon nanorings on silicon film on silica substrate. Using finite difference time domain (FDTD) simulations, it is found that the spectral linewidth of the optical filter is primarily controlled by nanoring width and is tolerant to the variations of the size and height of silicon nanorings. FDTD simulations also reveal that the excited guided mode is more tightly confined in the nanoring structures with smaller ring widths. It is explained that the narrow spectral linewidth of the nanoring structure filter is due to the smaller scattering cross-section of the silicon nanorings and tighter confinement of the guided mode. Our optimally designed optical reflection filter exhibits a 2.4 nm spectral linewidth with nearly 100% peak reflectance at the resonance wavelength.

中文翻译：

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二维硅纳米环阵列可实现偏振无关的窄光谱线宽光学滤波器

在本文中，我们就我们所知，研究了一种新型的导模谐振光学滤波器，该滤波器在垂直入射时具有偏振独立性，而在近红外范围内具有相对窄的光谱线宽。新的光谱滤光片由二氧化硅基板上硅膜上的硅纳米环的二维阵列组成。通过使用时域有限差分（FDTD）模拟，发现滤光器的光谱线宽主要受纳米环宽度控制，并且可以容忍硅纳米环尺寸和高度的变化。FDTD仿真还表明，激发的引导模式更紧密地限制在​​具有较小环宽度的纳米环结构中。可以解释的是，纳米环结构滤光片的光谱线宽较窄是由于硅纳米环的散射截面较小以及引导模式的限制范围较窄。我们优化设计的光学反射滤光片具有2.4 nm的光谱线宽，在共振波长处具有近100％的峰值反射率。