Development of high-frequency scanning near-field microscopy and investigation of its applications

衍射效应将传统成像显微镜的分辨率限制在所使用的辐射波长范围内。然而，扫描近场显微镜技术可以实现低于衍射极限的亚波长分辨率。本研究项目的目的是在我们原有的毫米波和太赫兹显微镜系统的基础上，利用我们主要在毫米波区域开发的金属狭缝式探针，开发毫米波和太赫兹区域的新显微镜格式及其相关技术，并研究毫米波和太赫兹显微镜的新应用。我们提出并实验证明了扫描近场各向异性显微镜在毫米波区域，允许在观察对象的电各向异性的观察。我们还提出了一种完全无损和非侵入性测量的被动显微镜格式，并成功地通过实验证明了其在毫米波区域的图像重建原理。为了提高狭缝探针的测量灵敏度，我们提出、设计并制作了一种用于毫米波显微镜的谐振狭缝探针。在毫米波区域进行的实验表明，谐振探头的灵敏度比传统的锥形缝型探头高十倍以上。为了演示使用狭缝型探针的太赫兹显微镜，我们尝试优化在0.3太赫兹太赫兹频段工作的锥形狭缝探针的几何形状。根据优化过程得出的设计准则，采用电成形技术制备了锥形狭缝探针。结果表明，该探针的射频性能实测值与有限元法预测值吻合较好。我们已经将上述显微镜格式和技术应用于毫米波区域的平面介质衬底、液晶材料等的表征。实验验证了该方法的有效性。少

Diffraction effects limit the resolution of conventional imaging microscopes to about the radiation wavelength used. However, sub-wavelength resolution below the diffraction limit can be achieved by the technique of scanning near-filed microscopy. The objective of this research project is to develop new microscopy formats and their related technologies in the millimeter-wave and terahertz regions in regard to our original microscope system using a metal slit-type probe that we had developed mainly in the millimeter-wave region, and to investigate new applications of the millimeter-wave and terahertz microscopy.We have proposed and experimentally demonstrated scanning near-field anisotropy microscopy in the millimeter-wave region, permitting the observation of electrical anisotropy in the viewed object. We also proposed a passive microscopy format that enables completely non-destructive and non-invasive measurements and succeeded to experimentally demonstrate its image reconstruction pr … More inciple in the millimeter-wave region. In order to improve measurement sensitivity of the slit probe, we have proposed, designed and fabricated a resonant slit-type probe for millimeter-wave microscopy. Experiments performed in the millimeter-wave region show that the resonant probe has more than ten times greater sensitivity than a conventional tapered slit-type probe.To demonstrate terahertz microscopy using a slit-type probe, we have tried to optimize the geometry of the tapered slit probe operated at a terahertz frequency band of 0.3 THz. Based on the design criteria derived from the optimization process, a tapered slit probe was fabricated by electro-forming technique. We have verified that the measured RF performance of the probe agrees well with the predicted one obtained using the finite element method.We have applied the above mentioned microscopy formats and technologies to the characterization of planar dielectric substrates, liquid crystal materials etc. in the millimeter-wave region. Effectiveness of them has been experimentally verified. Less