【作者】 矫雷子；

【导师】 赵明富；

【作者基本信息】 重庆理工大学 ， 信号与信息处理， 2011， 硕士

【摘要】 光纤倏逝波传感技术是一种高灵敏度的微量分析技术,在临床医学、水质检测、食品卫生检测和生物战剂检测等方面具有广泛的应用。其探测机理是通过传感区域围绕纤芯的待测物质对特定波段的倏逝波进行吸收,造成倏逝波的衰减,通过检测作用前后光强的衰减量,确定待测物质的含量。光纤倏逝波传感器的传感区域结构参数将影响传感器的灵敏度。因此,传感区域理论模型是研究整个光纤倏逝波传感技术的首要任务。基于几何光学,建立了锥形过渡区域透射深度关于锥形参数的数学模型、传感区域均匀部分有效吸收路径关于感应芯径和感应长度的数学模型,并对各个模型进行了研究。讨论了不同锥形参数(发射角、锥度比、锥长)下倏逝波的透射深度,传感区域均匀部分的不同光纤芯径和长度下倏逝波的有效吸收路径,并进行了仿真。仿真结果表明:在传感区域锥形过渡部分,选择合适的锥形光纤几何体和发射角,可以使得透射深度增大近3倍,当锥度比为0.4时,透射深度最大;在传感区域均匀部分,减小光纤芯径,增大光纤长度可以提高传感区域倏逝波的有效吸收路径。这些结论可以用来指导制作高灵敏度光纤倏逝波传感器。依据这些结论,选用石英光纤和HF腐蚀试剂,利用静动结合腐蚀方法,制作了锥形光纤倏逝波传感器。本文首先选用基于光纤光谱仪的生物膜活性检测系统,用来得到附着在传感器感应区域的生物膜生长过程中的变化吸收光谱图。利用此光谱图,结合生物膜生长过程中的传感区域的电子显微镜照片,可以得到生物膜的特征吸收波长。在此基础上,选用合适的LED光源和探测器,采用脉冲调制方法,开发了基于窄带发光LED的生物膜活性检测平台。两种方法实验结果表明,特征波长处吸收度随时间的变化与细菌数量随时间的变化较吻合,基本实现了生物膜活性的在线检测。更多还原

【Abstract】 Evanescent wave sensing technology is a high sensitive microanalysis technology, widely used in clinical medicine, water quality monitoring, food safe and biological warfare agent detection. Mechanism of the technology is made use of the absorption that material surrounding the fiber core interacted with the specific band evanescent wave. The material content can be detected through using variation of light density caused by the absorption. The structural parameters of sensing region will influence on the sensitivity of fiber optical evanescent wave sensor. Therefore, theoretical model for sensing region is a primary task for researching evanescent wave sensing technology. Mathematical models are established based on the geometrical optics, respectively for penetration depth and taper parameters in conical transition region, effective absorptive path and sensing fiber core and length in uniform sensing region. Penetration depth in different tapered parameters and effective absorptive path in different are discussed and simulated. The simulation result indicates that penetration depth can be increased about three times through selecting suitable taper parameters and reaches a maximum when the taper ratio is equaled to 0.4, and the effective absorptive path can be enhanced when decrease fiber core and increase fiber length in the sensing region. These results can be used to guide to make high sensitive fiber optical evanescent wave sensor. Silica optical fiber and HF corrosive reagent is selected, and tapered fiber optical evanescent wave sensor is manufactured based on the static-dynamic combination etching method. In this paper, biofilm active detection system based on the fiber spectrometer is used firstly to get absorption spectrogram for the process of biofilm development. The feature absorption wavelength of biofilm can be got from the absorption spectrogram and electron microscope figure of biofilm development on the sensing region. According to this absorption wavelength, suitable wavelength LED and PIN photoelectric detector are selected, then a biofilm active monitor system is developed based on the PWM. The experimental results from this two monitor systems show that the absorbance time-varying in feature wavelength is according with bacteria number time-varying, basically implementing the online monitoring of biofilm active.更多还原