【作者】 阎杰；

【导师】 明海； 鲁拥华；

【作者基本信息】 中国科学技术大学 ， 光学， 2010， 博士

【摘要】 本论文是在国家重点基础研究发展计划(973)项目,No.2006cb302905；国家自然科学基金重点项目,60736037；国家自然科学基金,10704070的资助下完成的。主要从理论和实验上研究了轴对称偏振光束激励表面等离子体共振在特殊结构中的性质和应用,以及发光层厚度对金属增强荧光辐射的影响。本论文主要的研究工作和成果和创新点如下：1.对径向偏振光聚焦光斑进行了理论计算。研究发现只有经透镜折射后的光线与光轴的最大夹角超过70度时,聚焦光斑直径才小于同样聚焦条件下线偏振光在其偏振方向的聚焦光斑直径,但仍大于线偏振光垂直于偏振方向的聚焦光斑。通过在光路中加入光阑的方法,能进一步减小径向偏振光的聚焦光斑直径。如在聚焦数值孔径为NA=1.4,加入光阑的大小为NA=1时,聚焦光斑的直径只有加光阑前的0.64倍。同样的方法应用于线偏振光聚焦也能减小聚焦光斑垂直于偏振方向的光斑直径,但沿偏振方向的光斑会增大。径向偏振光只能在一定范围内在一维方向减小聚焦光斑的直径。2.我们研究了径向偏振光照明的光纤SPR传感器的传感特性。由于径向偏振光光束截面上偏振态中心对称分布的特性,可以更有效的激励SRP,具有更高的灵敏度。理论与实验结果表明与线偏振光照明的情况相比,径向偏振光照明的光纤SPR传感器能够提高3倍的灵敏度。3.研究了轴对称偏振光束在泄露辐射模显微镜激励SPR的应用。首先通过SPR泄露场的成像观察,研究了泄露辐射模显微镜激励SPR的特点。利用轴对称偏振光束照明的泄露辐射模显微镜激励SPR,在物镜后焦面成像测量样品的空间傅立叶光谱信息,可以准确的测量超薄有机膜(小于100nm)的厚度。并利用角向偏振光在不同空间位置偏振方向不一样的特点,测量介质双折射。实验中利用角向偏振光照明泄露辐射模显微镜激励波导模共振的方式测量了双折射率差为Δn≈0.005的偶氮聚合物的双折射特性。4.理论分析了发光层厚度变化对金属增强荧光辐射的影响。计算结果表明,随发光层厚度的增加,MEF先是急剧增大,然后变缓,最后缓慢减小。实验中我们获得发光层厚度变化在15nm-70nm的薄膜并测量了其荧光增强因子,结果与理论分析基本一致,实验中获得大约5倍的荧光辐射增强因子。更多还原

【Abstract】 The research work within this dissertation is supported by the National Key Basic Research Program of China (No.2006CB302905), the Key Program of National Natural Science Foundation of China (No.60736037), the National Natural Science Foundation of China (No.10704070) and so on. The applications of cylindrical vector beams in some special structure to excite surface plasmon resonance and the effects of metal enhanced fluorescence with different emission film thickness are studied experimentally and theoretically.The main research works and highlights are as following:1. By study the focal character of radially polarized beams and linear polarized beams, we find that only when the angle between refract light and optical axis larger than 70 degree, the focal spot size of radially polarized beams is smaller than the linear polarized beams focal spot along the polarization direction. But it is still larger than the spot in perpendicular direction. By the method of add in an aperture diaphragm, the spot size of radially polarized beams can be reduce. The focal spot with an aperture diaphragm of diameter N.A=1 is smaller than the spot without aperture diaphragm of 0.64 times under the focal N.A=1.4. This method is not suit for linear polarized beams situation. By using radially polarized beams, the focal spot size can be reduced along one direction in a certain range.2. We study the sensing properties of fiber-optic surface plasmon resonance using radially polarized beams. Because of the rotational symmetry of sensing fiber, radially polarized beams have high efficiency to excite surface plasmon and have high sensitivity. Both the experiment and simulation result show the sensitivity of radially polarized beams is about 3 times higher than that of linear polarized beam.3. We study the application of cylindrical vector beams in leaky radiation mode microscope excitation structure. First we study the character of SPR excitation of leaky radiation mode microscope by imaging the SPR leaky mode. Then we observe the image on back focal plane of objective lens to get the information of sample. By using radially polarized beams illumination, it can measure the thickness of thin film accurately (smaller than 100nm). The azimuthally polarized beams have different polarization in different spatial location. Using of this character, we can measure the birefringence. In experiment, we measure the birefringence ofΔn≈0.005 by using the waveguide mode resonance excited by leaky radiation mode microscope with azimuthally polarized beams illumination.4. The influence of emission film thickness to metal enhanced fluorescence is analyzed theoretical. Calculation results show that when the emission film thickness increase, MEF increased quickly at first. Then the increasing of MEF slows down. Finally, the MEF reduced as emission film thickness increase. In experiment we change the emission film from 15nm to 70nm and obtain the enhancement of 5-fold. The experimental results are coincident qualitatively to the predictions of an integral enhanced fluorescent mode.更多还原