【作者】 吴云良；

【导师】 王克逸；

【作者基本信息】 中国科学技术大学 ， 测试计量技术及仪器， 2010， 博士

【摘要】 扫描近场光学显微镜(Scanning Near-field Optical Microscopy, SNOM)是将扫描探针显微镜技术移植到了光学领域,从而得到超衍射极限分辨率的光学图像。经过几十年的发展,SNOM横向分辨率大大的提高了,已经从最初的几十纳米提高到十几纳米,并且扫描成像的稳定性很高。虽然SNOM的分辨率比STM、AFM低,但其长处在于能获得样品亚波长分辨的光学图像,在多个研究和产业领域都有着广泛的应用。本文从传统SNOM中存在的扫描非线性,扫描速度慢等问题出发,搭建了基于双DSP控制系统和扫描头模块化的SNOM系统,建立了非线性校正的模型及算法,设计并初步实验了一种高速扫描的石英片-光纤探针组件,和设计了一种基于四个压电陶瓷管的新的XYZ扫描台系统。本文的研究工作主要包括以下几个方面：1、搭建了以DSP为核心的插板式的SNOM控制系统,为近场光学领域内的研究提供了一个良好的平台。主要模块包括控制扫描和各种信号采集的DSP主控板,探针-样品距离的DSP反馈控制板,用于提供给反馈信号的相位检测控制板等。完成了XY扫描控制算法,和探针-样品距离控制的PID算法。2、分析了SNOM扫描器产生非线性的原因,建立了SNOM扫描非线性校正模型,完成了用于非线性校正的软件预校正算法,有效的改善了图像的非线性。设计了一种基于实时监测探针位置附加系统,用于非线性校正的扫描头,预先采集不同电压下探针的位置数据,并通过二次多项式拟合算法和神经网络算法对位置-电压数据进行了处理,得到能输出线性位移的电压-位移模型。3、提出了一种高频石英片-光纤探针结构,可以显著提高SNOM扫描速度。利用二阶机械系统模型分析了音叉探针-样品距离控制的原理,比较得出用相位信号来作为反馈信号比振幅信号有更好的响应速度,分析得出SNOM扫描速度慢的主要因素来源于音叉探针,于是我们设计了一种石英片-光纤探针,并尝试了多种粘针方法,测试了其谐振频率,Q值等各种性能。4、由于单个压电陶瓷管弯曲量比伸长量大很多,设计了四个压电陶瓷管通过柔性铰链连接样品台的新扫描台结构,可以使样品台满足XYZ各个方向均有较大的动态范围。并用有限元方法对其进行了静态和动态性能的仿真分析。通过对样品台XYZ位移的测量,验证了理论仿真的正确性。更多还原

【Abstract】 With the help of scanning probe technique applied in optical field, the super high-resolution images beyond the diffraction limit can be obtained with the Scanning Near-field Optical Microscopy(SNOM). In the past decades the lateral and the stability of SNOM has been advanced greatly than before. Though the resolution of which is still lower than Scanning Tunneling Microscopy(STM) and Atomic Force Microscopy(AFM), SNOM has its own advantage to obtain the optical contrast information of the sample. In this thesis the disadvantage of traditional SNOM such as the nonlinearity and the slower scanning speed are discussed and a new set of the modular SNOM with a pair of DSP control system is built; A module of scan head with collecting real timely nonlinearity data is developed and the arithmetic of the scanning nonlinearity correcting is build up; A quartz pitch-optical fiber resonator probe to improve the scanning speed of SNOM and a new type scanner with four piezoelectric tubes are designed and experimented.The main research contents of this thesis are listed as follows:1. A new set of SNOM using DSP controlling system is built up. There are several modules:the main DSP controlling system, the feedback DSP system which control the tip-sample distance, the phase detecting system which supply the feedback signal to the feedback DSP system, and so on. The XY scan control arithmetic and PID control arithmetic are developed.2. The exsistence of nonlinearity in the scanner of SNOM is analysed. Image post-processing software for the correction of scanning nonlinearity is developed. A scanner with a PSD which can get the tip’s position in real-time is designed and experimented. The quadratic polynomial model and the BP model of Neural-Net Algorithms are introduced to process the scanner nonlinearity data and to get the modle of linearity correction.3. A new module of the quartz pitch-optical fiber probe is advanced which has higher scanning speeds than the module of the tuning fork-optical fiber probe. The response speed of tip-sample distance change using the phase regulation is more quickly than that with the amplitude.4. A new scanner based on four piezoelectric tubes connected with spring hinge and sample stage is designed. The FEM software of ANSYS is used to analyse the mechanics behavior of the scanner:The XYZ scanning ranges of this new scanner are all bigger in three dimension; This new scanner’s static and dynamic properties simulation with the finite element method has carried, and its pre-experiment has accomplished.更多还原