【作者】 李海伟；

【导师】 江俊峰；

【作者基本信息】 天津大学 ， 光学工程， 2010， 硕士

【摘要】 基于回音壁谐振模式(WGM)的光学微腔生物传感器灵敏度高,体积小,能对微量生物化学分子进行无标记检测,具有重要的研究价值和很好的应用前景。本论文基于微毛细管建立光微流体生物传感器,进行了微管传感模型理论推导,采用时域有限差分算法进行了微环传感器的数值模拟和分析,搭建实验系统进行了微流体传感初步检测实验。完成的主要工作如下:基于耦合模式理论,研究直波导和微管的耦合性质,建立微管传感的理论模型,得到微管结构的性能参数如谐振波长、自由光谱范围FSR、品质因子Q、峰值半高宽等。从麦克斯韦方程组出发推导柱坐标下微毛细管中的电磁场分布方程,根据径向电场分布曲线,得出微毛细管内外半径和折射率之间应该满足的关系。推导微管谐振腔的耦合解析模型,为增强透射谱下陷深度,提出三种互耦合结构:在直波导耦合区植入光栅,在微管壁植入光栅以及双管结构。理论分析了光栅和双管的互耦合作用。利用Fullwave软件对微管谐振器理论模型进行数值模拟,研究各参数变化之间的关系,计算了微腔的径向以及周向电场分布图样。进行了光栅参数以及同心环参数设计和仿真。利用ZF13棱镜经倏逝场激发微毛细管WGM模式,搭建了微流体生物传感装置,向微毛细管中注入不同浓度的乙醇溶液改变有效折射率,从而使谐振波长发生漂移。通过对不同波段的光波在不同入射角度的实验结果进行分析,得到相应灵敏度。更多还原

【Abstract】 Opto-fluidic biosensor based on microcapillary, with its unique resonant whispering gallery mode (WGM), which allows high sensing sensitivity, realizes the label-free detection of biological reagents. Also, due to the small size and easy to integrate, this biosensor has very important research value and application prospects. The main point of this paper is to establish a theoretical model of the optic micro fluid biosensor, and to build an experiment system in order to implement the micro fluid sensing detection, combined with the model. The analysis method is that, first, theoretically derivate the relevant parameters of the micro-ring sensing model, then numerically simulate the micro-ring sensor based on the well-known finite-difference time-domain(FDTD) algorithm, finally set up the experiment system to achieve the micro-ring biosensor and analyze the results using the theoretical calculation. The major works completed are as follows:Based on the coupling mode theory and the FDTD method, the property of the coupling between the straight waveguide and the micro-ring is thoroughly investigated, the theoretical model of the micro-ring resonators are established, and at last get the performance parameters of the micro-ring structure , such as resonant wavelength, free spectral range, quality factor and peak width at half, etc. We deduce the distribution of the electromagnetic field equations under the cylindrical coordinate from Maxwell’s equations, and according to the radial electric field profile, we get the required relationship between the corresponding structure parameters. Enhanced notch depth is demonstrated in micro-ring resonator which is generated either by the nanometer-scaled gratings along the ring sidewalls or by evanescent directional coupling between two concentric rings.Based on the FDTD algorithm, using the FULLWAVE simulation engine which is a part of the RSoft Photonic Suite simulates the theoretical models of the micro-ring resonators. The relationship between parameters, radial and circumferential electric field pattern observed by simulating. Grating-assisted and concentric micro-ring resonators with different parameters are simulated.Microcapillary biosensor was established with a prism and a microcapillary. With the prism made from ZF13 material, WGM of the microcapillary is successfully observed by evanescent coupling. The mixture of water and ethanol were used for experiment research on refractive index change sensitivity of microcapillary biosensor. Sensitivity of the biosensor observed in different incident angles.更多还原