基于马赫-曾德干涉仪的色散转折效应及其传感性能模拟研究

设计了工作在近红外波段的硅基马赫-曾德尔干涉仪(MZI)折射率传感器。理论和仿真模拟分析表明,通过改变MZI的结构参数可以对输出干涉谱的色散转折特性进行调控,经过优化后色散转折点(DTP)所对应的波长可以调至近红外波段(1550 nm),通过改变MZI周围的环境折射率(SRI)可以使折射率灵敏度达到37500 nm/RIU。由于DTP两侧的干涉条纹对外界折射率响应有相反的特性,将干涉波谷的相对漂移量作为检测对象,能够将灵敏度提高2倍,即75000 nm/RIU。不同于常规基于光栅和波导耦合构架的DTP传感器,所设计的DTP结构中两个干涉模式互不相关且均可独立调控,并可根据需要灵活调控色散转折波长。     

Numerical study of a highly sensitive surface plasmon resonance sensor based on circular-lattice holey fiber

A new design of surface plasmon resonance (SPR) sensor employing circular-lattice holey fiber to achieve high-sensitivity detection is proposed. The sensing performance of the proposed sensor is numerically investigated and the results indicate that our proposed SPR sensor can be applied to the near-mid infrared detection. Moreover, the maximum wavelength sensitivity of our proposed sensor can reach as high as 1.76×10⁴ nm/refractive index unit (RIU) and the maximum wavelength interrogation resolution can be up to 5.68×10^-6 RIU when the refractive index (RI) of analyte lies in (1.31, 1.36). Thanks to its excellent sensing performance, our proposed SPR sensor will have great potential applications for biological analytes detection, food safety control, bio-molecules detection and so on.     

铁酸镍/碳复合中空多壳层结构的制备及吸波性能

采用次序模板法合成了单、双壳层的中空铁酸镍(NiFe₂O₄)材料,通过改变前驱体溶液组成及煅烧条件等因素实现了对产物形貌的调控.在中空NiFe₂O₄颗粒表面原位包覆聚多巴胺,再经过碳化处理,制备了具有中空多壳层结构(HoMS)的NiFe₂O₄/C复合吸波材料;考察了其电磁参数,计算了其吸波性能,分析了不同复合结构对性能的影响.结果表明,中空多壳层结构能够显著降低材料的密度,而碳薄层不仅能够改善其阻抗匹配性,而且提升了材料的反射损耗性能.其中,双壳层NiFe₂O₄/C复合物的吸波性能最佳,当样品厚度为3.5 mm时,材料在8.44 GHz处反射损失最小,为-32.35 dB;当样品厚度为2.0 mm时,材料在14.01～17.69 GHz范围内反射损耗小于-10 d B,有效吸收频宽为3.68 GHz.这些优异性能主要源于独特的中空多壳层结构增加了电磁波多次反射/散射的概率,提供了更多的界面极化,实现了电磁波的快速...