基于表面等离子体共振技术的紫外探测研究

发布时间：2018-04-11 15:50

本文选题：表面等离子体共振 + 磁控射频溅射　；参考：《中国科学技术大学》2015年博士论文

【摘要】：表面等离子体共振技术(SPR)作为一种高折射率灵敏度的光学探测技术,在各种领域都得到广泛的推广使用。利用表面等离子体共振技术的优势,可以对一些光功能材料进行研究,并能拓展光功能材料的使用领域。本论文主要对表面等离子体共振技术进行了研究,并将其推广到紫外探测领域。本论文的主要工作和研究成果如下： 1、利用射频磁控溅射镀膜系统在高折射率棱镜底面镀制金膜,制作了Kreschmann式SPR探测结构,然后搭建了SPR角度扫描平台。扫描平台使用两个步进电机控制的转台,系统的角度扫描分辨率可达0.0020,利用编写的控制软件可以实现SPR曲线的实时观测记录,整个平台的搭建为之后的SPR探测研究提供了基础。 2、提出了一种利用氟代偶氮苯聚合物作为传感材料的新式SPR紫外探测技术。由于不同强度紫外光照射下,氟代偶氮苯聚合物的光致顺反异构速率不同,导致聚合物折射率变化速率不同,进而影响了SPR系统反射光强度变化速率,通过测量反射光强度变化速率就能得到紫外光的强度信息,这种方法同传统的单纯测量稳定状态下反射光强度的方法相比,所需的测量时间短,可以低于1分钟。这种方法的紫外测量灵敏度为4.43(mv/s)/(mw/cm2),在缩短了测量时间的情况下也保证了较高的测量精度。 3、设计了一种新的紫外光分布成像系统。本系统是基于Kreschmann结构的SPR探测技术,使用氟代偶氮苯聚合物作为敏感材料。紫外光照射区域的偶氮苯聚合物薄膜折射率降低,导致这部分对应的反射光强度增强,而未照到部分的反射光强保持不变。通过提取紫外光照射前后采集到的反射光图像之间的变化,可以得到紫外光分布的图像。使用不同形状的光阑来改变紫外光的分布情况,测试了系统的可行性。 4、提出了一种双入射角式SPR探测方法。传统的单入射角强度调制式SPR探测方法是以选定的单个入射角处的反射光强度作为系统的输出量,而双入射角式SPR方法是利用两个选定的入射角处的反射光强度的差值作为系统的输出量,可以充分利用采集到的SPR数据,有效提高了探测灵敏度。利用不同浓度的NaCl溶液对这种探测方法进行了检测,发现折射率探测灵敏度比传统的单入射角式SPR探测系统提高了59%,折射率探测精度达到8.25×10-6RIU。同传统的单入射角式SPR方法相比,双入射角式SPR探测的方法没有增加系统的复杂度,利用原有的结构就能实现很好的探测效果。
[Abstract]:Surface Plasmon Resonance (SPR), as an optical detection technique with high refractive index sensitivity, has been widely used in various fields.With the advantage of surface plasmon resonance (SPR) technology, some optical functional materials can be studied, and the application fields of optical functional materials can be expanded.In this paper, surface plasmon resonance (SPR) technology is studied and extended to UV detection.The main work and research results of this thesis are as follows:1. Using RF magnetron sputtering system to fabricate gold film on the bottom of high refractive index prism, Kreschmann type SPR detection structure is fabricated, and then the SPR angle scanning platform is built.The scanning platform uses two turntables controlled by stepper motors and the angular scanning resolution of the system can reach 0.0020. The real-time observation and recording of SPR curves can be realized by using the control software written. The whole platform provides a foundation for the later research of SPR detection.2. A novel SPR UV detection technique using fluoroazobenzene polymer as sensing material is proposed.Because of the different photoinduced isomerization rate of fluoroazobenzene polymer under different ultraviolet light intensity, the change rate of refractive index of polymer is different, and the change rate of reflected light intensity of SPR system is affected.The intensity information of ultraviolet light can be obtained by measuring the change rate of reflected light intensity. Compared with the traditional method of measuring the intensity of reflected light in stable state, the measuring time is shorter and can be less than one minute.The UV measurement sensitivity of this method is 4.43 mv / s / mw / cm ~ (2), and the measurement time is shortened and the measurement accuracy is high.3. A new UV distribution imaging system is designed.This system is based on Kreschmann structure of SPR detection technology, using fluoroazobenzene polymer as a sensitive material.The refractive index of azobenzene polymer film decreases in the ultraviolet region, which leads to the enhancement of the corresponding reflected light intensity, while the reflection intensity of the unilluminated part remains unchanged.The distribution of ultraviolet light can be obtained by extracting the changes of reflected light images before and after UV irradiation.The feasibility of the system is tested by changing the distribution of ultraviolet light with different apertures.4. A double incident angle SPR detection method is proposed.The traditional single incident angle intensity modulation SPR detection method takes the reflected light intensity at the selected single incident angle as the output of the system.The double incident angle SPR method uses the difference of reflected light intensity at two selected incident angles as the output of the system, which can make full use of the collected SPR data and effectively improve the detection sensitivity.The sensitivity of refractive index detection is 59% higher than that of traditional single incident angle SPR detection system, and the precision of refractive index detection is 8.25 脳 10 ~ (-6) RIU.Compared with the traditional single incident angle SPR method, the double incident angle SPR detection method does not increase the complexity of the system, and the original structure can achieve a good detection effect.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN23

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