高灵敏度光学薄膜弱吸收测量仪的研制
文献类型：学位论文
| 作者 | 范树海 |
| 学位类别 | 博士 |
| 答辩日期 | 2005 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 邵建达 |
| 关键词 | 吸收测量 薄膜 表面热透镜 光热形变 热波成像 |
| 其他题名 | High sensitive weak absorption apparatus for optical coatings |
| 中文摘要 | 吸收损耗是影响薄膜性能的重要参数。现代光学系统尤其是强激光系统中常用光学薄膜的吸收率已达lppm量级甚至更小，而传统的薄膜吸收测量方法，如分光光度法、消光系数法、量热法，光热辐射法等因其灵敏度低，已无法满足测量要求。光热技术的发展为薄膜微弱吸收的测量提供了新的手段，其中表面热透镜技术更以其灵敏度高、调节方便等优点受到人们的青睐。本文在综述了薄膜吸收的来源、定义和测量手段后，详细论述了表面热透镜薄膜微弱吸收测量理论，在热波传导理论和线性热膨胀理论的基础上提出了薄膜系统光热形变简化理论，完善了表面热透镜形变检测理论。在这些理论的基础上，通过数值模拟对表面热透镜信号进行深入分析，提出了一系列提高薄膜吸收测量灵敏度、确保吸收测量线性度和准确性的方法。依据上述理论建立了薄膜弱吸收测量仪样机。本文详细说明了该仪器的组成结构、软件设计、探测电路和使用步骤；对仪器噪声和误差的来源进行了细致的分析并给出了消除或抑制的方法；结合实验结果给出了该样机的主要性能参数：良好的薄膜吸收率测量线性度；稳定在10PPb量级的灵敏度；优于IPPm的重复精度。本仪器除了能够对薄膜吸收率进行点测、线扫描和面扫描测量外，还能对任何表面平滑样品一定厚度的表面层进行热波显微成像。扫描测量的定位精度达1μm，30mm范围内的重复定位精度达3μm，扫描及成像的空间分辨率达25μm·文中还给出了一系列薄膜吸收率测量结果并进行了简单的分析，包括小光斑扫描预处理、退火处理、离子辅助参数、氧分压对薄膜吸收率的影响等等。此外还给出热波显微扫描成像结果，成功的显示了吸收率和热缺陷的分布情况。最后对论文工作进行了总结，对下一步工作提出了建议。 |
| 英文摘要 | Absorption is one of the important characters of coatings. In modern optical system, especially in high power laser related system, the absorption of coatings has been reduced to lppm magnitude or even lower. Traditional measuring methods for coating absorption including spectrophotometric method, extinction coefficient calculation method, calorimetric method and optitherm radiation method have no enough sensitivity. With the development of photothermal technique, new methods to measure weak absorption of coatings are developed. Among them, STL (Surface Thermal Lens) technique is recommended for its high sensitivity and handleability. In this paper, the overviews of sources, definitions and measuring methods of coating absorption are presented. After that, the theory of STL coating absorption measurement method is discussed. A simplified theory of photothermal deformation of coatings is developed based on thermal wave transmission theory and linear thermal expansion theory. The theory of STL deformation detection is improved. STL signal is analyzed by numerical simulation based on the above theories. A series of methods to improve absorption measurement sensitivity and ensure linearity and accuracy are developed. A prototype machine for weak absorption measurement of optical coatings is constructed based on STL theory. The structure, software, detection circuit and operating procedure of the apparatus are described. The noise and error of the apparatus are analyzed and the methods to control them are given. The main characters of the apparatus are given by measurement results. It has good linearity; the sensitivity reaches lOppb stably; the repeatability precision is better than lppm. The apparatus can not only measure coating absorption by point measurement, line scan and surface scan, but also perform thermal wave micrography of surface layer of any smooth sample. While doing scanning measurement, the positioning accuracy is 1 urn, the repeatability positioning accuracy is 3um corresponding to a scan distance of 30mm. The spatial resolution is 25um while doing scanning measurement and micrography. Some measurement results are given showing the absorption-changing effect of optical coatings caused by annealing, focusing laser scanning preprocessing and etc. Some thermal wave micrography results show the distribution of absorption and thermal defects. At the end of this paper, all the works are concluded and some suggestions to following works are given. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15490]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 范树海. 高灵敏度光学薄膜弱吸收测量仪的研制[D]. 中国科学院上海光学精密机械研究所. 2005. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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