A finite-difference-time-domain (FDTD) approach is undertaken to investigate the extraordinary optical transmission (EOT) phenomenon of Au circular aperture arrays deposited on a Bragg fiber facet for refractive index (RI) sensing. Investigation shows that the choice of effective indices and modal loss of the Bragg fiber core modes will affect the sensitivity enhancement by using a mode analysis approach. The critical parameters of Bragg fiber including the middle dielectric RI, as well as its gap between dielectric layers, which affect the EOT and RI sensitivity for the sensor, are discussed and optimized. It is demonstrated that a better sensitivity of 156 ± 5 nm per refractive index unit (RIU) and an averaged figure of merit exceeding 3.5 RIU⁻¹ are achieved when RI is 1.5 and gap is 0.02 μm in this structure.

中文翻译：

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在布拉格光纤小平面上使用Au孔径阵列进行折射率传感建模

进行时域有限差分（FDTD）方法来研究沉积在布拉格光纤刻面上用于折射率（RI）传感的Au圆形孔径阵列的非常规光学传输（EOT）现象。调查表明，使用模式分析方法选择布拉格光纤纤芯模式的有效指标和模态损耗将影响灵敏度的提高。讨论并优化了包括中间电介质RI在内的布拉格光纤的关键参数以及介电层之间的间隙，这些参数会影响传感器的EOT和RI灵敏度。结果表明，每个折射率单位（RIU）的灵敏度更高，为156±5 nm，平均品质因数超过3.5 RIU ^-1 在该结构中，当RI为1.5且间隙为0.02μm时，获得了Δθ。