【作者】 安岩；

【导师】 孙强；

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) ， 光学工程， 2014， 博士

【摘要】 手持式拉曼光谱技术具有信息丰富、分析能力强、处理速度快、样品无需预处理、使用方便等特点,使其广泛应用于水污染监测、毒品走私、大气质量监测、文物鉴别、药品检测等领域。国外手持式拉曼光谱技术比较成熟,并形成了一系列性能优异的产品,国内还处于起步阶段,其主要原因在于：手持式拉曼光谱仪器研制所需要的关键技术多,且不易突破。本文在考虑现在技术状况的基础上,主要针对拉曼探头外光路光学系统和光谱仪分光系统进行了研究。在拉曼光谱仪外光路光学系统方面,实现了小视场、大物方数值孔径的外光路光学系统设计,收集光路中采用球面系统时物方数值孔径达到0.33,采用非球面系统时物方数值孔径达到0.4,会聚光路中采用摄远结构,摄远比达到0.59,总长15厘米,实现了小体积情况下,外光路系统对于拉曼光谱信号的收集。同时,进一步分析了外光路杂散光来源,通过实际光线追迹,建立合理的杂散光分析模型,利用陷波滤光片、黑点板和孔径匹配等技术消除由镜面引起的激光反射、散射等杂散光。利用Tracepro软件进行光机建模分析,仿真结果表明此方法的抑制效果满足拉曼光谱仪要求的消杂光水平。在光谱仪设计方面,基于消彗差Czerny-Turner基础上,提出根据像面高度大小确定结构尺寸公式,并根据该结构设计了符合拉曼光谱应用且分辨率高达0.6nm的光谱仪系统。首次推导出交叉型消像散Czerny-Turner结构的零阶和一阶消像散条件,并给出了限制条件,与交叉型消彗差结构对比,在理论计算与软件仿真两方面验证下,证明了交叉型消像散结构均优于消彗差结构,其均方根半径减小了12%-52%,可见,前者更易得到良好的优化结果。为了提高设计效率,使设计工作更加智能可靠,本文还建立了消彗差和消像散C-T初始结构计算模型,并通过Matlab编制GUI,实现了与Zemax的直接通信,利用计算机自动输入代替手动输入,方便快捷。最终,实现了光谱分辨率优于0.6nm、拉曼光谱范围为781nm-1014nm的手持式拉曼光谱仪的优化设计和样机研制,样机尺寸为243mm×25mm×71mm。通过样机实验成功获得了CCL4的5个拉曼光谱特征峰,验证了整机拉曼光谱仪系统光学设计的可行性和合理性。为进一步研制小体积、优性能的手持式拉曼光谱仪奠定了良好的技术基础。更多还原

【Abstract】 With the features of rich information, strong analytical ability, fast processingspeed, without sample pretreatment and easy to use, handheld Raman spectrometeris widely used in water pollution monitoring, drug smuggling, air quality monitoring,cultural identification, drug testing and other areas. The technology of handheldRaman spectrum is relatively mature abroad, and series of excellent products havebeen applied. In China, the domestic applications are still in its infancy. The keytechnology of handheld Raman spectrometer is hard to break is the main blockingreason.In this paper, basing on the current technical condition, two main parts ofhandheld Raman spectrometer, the optical system of Raman probe and the gratingspectrometer, are studied. In terms of Raman probe, an optical system of handheldRaman probe with the total length of15cm, small field of view and large objectnumerical aperture has been designed. The object numerical aperture of collectingsystem is0.33using spherical optical technology and0.4using non-spherical opticaltechnology. The telephoto structure with the telephoto ratio of0.59has been used inconverging system. Meanwhile, the further analysis of stray light in optical systemof Raman probe has been investigated. By real ray tracing, a reasonable stray lightanalysis model has been established. Several technologies of eliminating the scattering stray light caused by the laser reflecting and scattering on lens surfacehave been proposed, such as the technology of notch filter, the technology of blackspots, the technology of aperture matching and so on. Using the optical simulationsoftware Tracepro, the opto-mechanical model of handheld Raman spectrometer hasbeen simulated. The simulation result shows that stray light suppression level meetsthe Raman spectral measuring requirements while using the eliminating stray lighttechnologies above. In terms of grating spectrometer, for coma-free Czerny-Turnerstructure the formula of determining the structure by the image size has beenproposed. Basing on this formula, the spectrometer with a high resolution of0.6nmand satisfying application requirements of Raman spectroscopy has been designed.In astigmatism-free Czerny-Turner structure, the zero-order and first-orderastigmatism-free conditions in crossed astigmatism-free structure have been derived,and the restricted conditions on system construction are presented. Thecorrespondent crossed coma-free Czerny-Turner structure has also been built up forthe comparison. It is shown in both of theoretical calculation and softwaresimulation, that the astigmatism-free crossed C-T structure has a superior opticalperformance, with RMS of spot diagram only12%to52%of that in thecorrespondent coma-free Czerny-Turner structure at the working wavelength. Theformer is easy to obtain good optimized results. In order to improve designefficiency, and to make work more intelligent and reliable, the initial structuremodels of coma-free and astigmatism-free have also been established by GUI inMatlab to directly communicating with Zemax, which make it convenient byautomatically input instead of manually input. Finally, we get the results of thespectral resolution better than0.6nm and the Raman spectral range from781nm to1014nm, with the prototype size of243mm×25mm×71mm. The five characteristicpeaks of Raman spectrum of CCL4have been successfully measured by theprototype of the Raman spectrometer, which verifies the feasibility and therationality of the optical design of the whole Raman spectrometer system. Thesehave established a good technical foundation of handheld Raman spectrometer for further development in reducing instrument size and improving excellentperformance.更多还原