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原子力与光子扫描隧道组合显微镜功能性样机
Photon Scanning Tuneling Microscope Conbined with Artomic Force Microscope Prototype
【作者】 章健;
【导师】 吴世法;
【作者基本信息】 大连理工大学 , 光学工程, 2005, 博士
【摘要】 扫描探针显微镜(SPM)当前的发展趋势是功能复合化和数字化。原子力与光子扫描隧道组合显微镜(AF/PSTM)就是一种数字化的兼有原子力显微镜(AFM)和光子扫描隧道显微镜(PSTM)功能的新型SPM。 一般(单光束)的PSTM在成像中,存在假象和样品光学图像与形貌图像难于分离两个困难。根据吴世法教授提出的解决这两个难题的概念设想,本人负责申请并获得国家自然科学面上青年科学基金:“AF/PSTM光纤尖共振调制成像模式”项目(原博士论文的开题报告)。通过对该仪器核心部件—双功能AF/PSTM光纤尖共振策动方案研究,并在国家和学校基金资助下,将课题目标提升为:研制新一代原子力与光子扫描隧道组合显微镜(AF/PSTM)功能性样机。 论文第一部分为绪论,主要介绍了SPM扫描探针显微镜的发展过程和现状,其中重点叙述了原子力显微镜(AFM)、光子扫描隧道显微镜(PSTM)和扫描近场光学显微镜(SNOM)等的基本原理,并阐明了在一般PSTM光学成像上存在假象和光学图像与形貌图像不能分解的两个问题。第二部分讲述AF/PSTM系统理论和总体设计,阐明了PSTM减少假象的原理,AF/PSTM光学信号的分解原理等。这些理论说明,通过使用AF/PSTM双功能弯光纤尖作探针,在共振调制轻敲等振幅成像模式下,AF/PSTM可以同时得到样品的光学折射率、透过率和形貌图像。由此,提出AF/PSTM样机的原理结构,将这些原理作为AF/PSTM系统设计要求的依据,形成了AF/PSTM样机的总体设计。第三部分根据样机的总体设计要求,说明AF/PSTM样机研制中几个重要环节:双功能光纤尖共振调制扫描工作模式,仪器主从式结构设计,PSTM光信号的图像分解的解算实时处理架构,电控主机箱的设计,以及光纤共振峰的搜索等。主从式结构设计可使系统能灵活地实现硬件升级,能较好地贴近商业性样机要求。第四部分介绍AF/PSTM样机研制中的监控软件设计,监控软件负责人机接口、DSP管理及其他模块在内的整个系统管理任务,它作为WINDOWS的应用程序也采用模块化设计,存储的文件格式和国际通用的格式兼容。第五部分详细介绍了DSP卡的设计,通过采用DSP卡,保障了AF/PSTM系统的主一从式结构的运行,同时负责扫描工作的反馈控制和结果上传。DSP卡的设计采
【Abstract】 A general trend of Scanning Probe Microscope (SPM) is to multiple functionality and digitalization. Atomic Force / Photon Scanning Tunneling Microscope (AF/ PSTM) is such a new type SPM instrument that combines the advantages of both Atomic Force Microscope (AFM) and Photon Scanning Tunneling Microscope (PSTM). By the using of AF/PSTM dual-functional bend optical fiber tip, AF/PSTM works at resonant modulation imaging mode, and gets two AFM images (topography and phase image) and two PSTM images (transmissivity and refractive index image) of sample simultaneously in once scanning.General (with single beam) PSTM has two difficulties at imaging, that one is the artifact false image in optical image another is the mixture of topography with optical image. Basing on the professor Wu ’s thesis on separating image method of AF/PSTM, author applied an item from National Science Youngest Fund on "photon scanning tunneling microscope (PSTM) tip resonance modulation imaging mode", which is the opening report of doctorial thesis. With supports of national fund and DLUT fund, this thesis title was extended to development of the functional prototype of new type AF/PSTM.In the first chapter of this doctorial thesis, the international development status of the Scanning Probe Microscope is introduced. The principles of AFM, PSTM and SNOM are described and as an important part the problems of PSTM are indicated.Second chapter, shows the basic theories of AF/PSTM including the theory on reducing PSTM optical artifact false image and theory on separating optical signal of PSTM. Basing on those theories, AF/PSTM dual-functions bend optical fiber tip shows that AF/PSTM how can get the transmissivity, refractive index image, topography and phase image of sample working at resonant modulation constant amplitude imaging mode. Then the schematic of AF/PSTM is formed and the whole system structure design is found.The third chapter inherits the second chapter’s request of design of AF/PSTM, describing how to develop AF/PSTM., in this part, the main works include: resolving resonance scanning mode with dual-functional optical fiber, designing principal-minor structure, real-time separating PSTM optical image signal, designing main instrument box, and searching resonance peak. The principal-minor structure could support hardware upgrading, and being close to commercial prototype instrument.The fourth chapter introduces the development of AF/PSTM host software. The monitor module manages the whole system, including the user interface, DSP card and main instrument box. The software is a WINDOWS application programmer, which bases on many modules. And the data files are compatible with DI Company of USA.The fifth chapter introduces the design of DSP card and DSP software.