石墨烯涂层高灵敏SPR-PCF的大气污染传感器及特性研究

Graphene coated SPR-PCF highly sensitive sensor for air pollutant detection

摘要:

为了提升大气污染物检测的灵敏度,提出一种基于高灵敏度石墨烯涂层的表面等离子体光子晶体光纤(Surface Plasmon Resonance-Photonic Crystal Fiber, SPR-PCF)传感器,并将其应用于大气污染物的检测。该传感器在纤芯外围镀上金膜,并采用六边形不同直径空气孔双排列的结构,在金薄膜与待测物之间涂敷一层敏感材料石墨烯,利用有限元方法,系统地分析了金属层厚度、空气孔间距及直径和石墨烯厚度等因素对SPR-PCF传感器灵敏度的影响。在折射率范围为1.398-1.402时,模拟结果显示,该传感器具有显著的表面等离子体共振效应,并分析得到了最优结构参数,此时传感性能几乎不受环境温度影响,最大波长灵敏度达到55000 nm/RIU,与之对应的波长分辨率为1.82×10-6 RIU。相比于同一折射率测量范围涂敷石墨烯的结构,所述SPR-PCF传感器的波长灵敏度是现有典型SPR-PCF传感器波长灵敏度的2.86-9.17倍,分辨率是已有典型SPR-PCF传感器的0.109-0.349。因此,在大气污染物浓度和种类检测方面,该SPR-PCF传感器有较好的应用前景。

Abstract:

In order to improve the sensitivity of air pollutants detection, a surface plasmon resonation-photonic crystal fiber sensor based on graphene coating with high sensitivity was proposed. And it is applied to the detection of air pollutants. The SPR-PCF sensor is coated with gold film around the core, and a layer of sensitive material graphene is coated between the gold film and the test object. The effects of the metal layer thickness, the spacing and diameter of air holes and the thickness of graphene on the sensitivity of the SPR-PCF sensor are systematically analyzed by using the finite element method. When the refractive index ranges from 1.398 to 1.402, the simulation results show that the sensor has significant surface plasmon resonance effect, and the optimal structural parameters are obtained by analysis. Currently, the sensing performance is almost unaffected by the ambient temperature. The maximum wavelength sensitivity reaches 55,000 nm/RIU, and the corresponding wavelength resolution is 1.82×10-6 RIU. Compared with the structure coated with graphene in the same refractive index measurement range, the wavelength sensitivity of the proposed SPR-PCF sensor is 2.86-9.17 times that of the existing typical SPR-PCF sensor, and the resolution is 0.109-0.349 that of the existing typical SPR-PCF sensor. Therefore, the SPR-PCF sensor has a good application prospect in the detection of atmospheric pollutant concentration and type.