PSTM金属样品成像实验的数值模拟

本文采用时域多分辨分析法（MRTD）,并利用FDTD方法的完全匹配层（UPML）作为边界条件,对Eckert等人在实验中所使用的喷溅金属铝小块样品作了数值模拟分析,给出了在PSTM模型中喷溅金属铝小块样品的数值模拟的三维图像,并对试验结果和理论结果进行了比较和分析,验证了Eckert等人的实验。     

双功能弯曲光纤探针的制作

探针是所有扫描探针显微镜的关键部件。本文提出了一种采用普通单模光纤制作在原子力和光子扫描隧道组合显微镜(AF/PSTM)上使用的弯曲光纤探针的方法。通过合理的选择实验参数,经过热拉伸与化学腐蚀两个过程,得到弯曲部分的角度为110°~120°、锥角约60°~80°的弯曲光纤探针。经扫描电镜观察,光纤探针的尖端直径小于100nm。此种方法加工光纤探针的成品率约70%左右。     

PSTM等强度扫描方式下减小假象的数值模拟

本文用多层薄膜理论的费涅耳系数矩阵法导出光子扫描隧道显微镜（ＰＳＴＭ）探测场计算公式,公式适用于四层介质三界面和三层介界面两种模式。用所得公式研究了等强度扫描下表面形貌测量时由样品表面起伏引起民附加的假象用π对称双照射样品方法减小假象。通过数值模拟给出了在不同入射角,偏振和不同探针至样品距离条件下减小假象的效果。上术 适用于ＰＳＴＭ测量样品折射率图像时减小由表面倾角引入的假象。     

热拉伸和化学腐蚀相结合制备弯曲光纤探针

提出了原子力/光子扫描隧道显微镜(AF/PSTM)系统的关键部分——双功能弯曲光纤探针的制作方法.采用热拉伸与动态、静态两步化学腐蚀相结合的方法制作出AF/PSTM弯曲光纤探针，弯曲角度约为150°，尖端曲率半径优于100nm，锥角范围为60°—90°.将这种双功能弯曲光纤探针应用在新研制的AF/PSTM系统上，同时获得了样品的光学与形貌图像，实现了图像分解. 关键词： 原子力/光子扫描隧道显微镜 光纤探针 热拉伸 化学腐蚀     

原子力与光子扫描隧道组合显微镜

介绍了超高分辨光于扫描隧遭显微镜（PSTM）的计冗历程,为解决第一代（单光束照明）光千扫捕隧逼显傲镜中存在人为假象和样品光学图像与形貌图像难于分离两个难题,用“对称双光束照明方法消假象,用原子力与光子扫描隧道组合显微镜（AF／PSTM）图像分解方法分离样品光学透过率、折射率与形貌图像。研制成功新一代原子力与光子扫描隧道组合显微镜（AF／PSTM）样机。该样机在一次扫描中已获得两幅原子力显微镜图像（形貌与相位）和两幅光学图像（透过率和折射率）,有效地减少了假象,分解了样品光学折射率、透过率与形貌图像。     

Review of near-field optical microscopy

This review has introduced a new near-field optical microscope (NOM)—atomic force microscope combined with photon scanning tunneling microscope (AF / PSTM). During scanning, AF/PSTM could get two optical images of refractive index image and transmissivity image, and two AFM images of topography image and phase image. A reflected near-field optical microscope (AF/RSNOM) has also been developed on AF/PSTM platform. The NOM has been reviewed in this paper and the comparison between AF/PSTM & RSNOM and the commercial A-SNOM & RNOM has also been discussed. The functions of AF/PSTM & RSNOM are much better than A-SNOM & RNOM.     

PSTM成像的FDTD数值模拟

尝试用时域有限差分法(FDTD)分析采用不同探针时光子扫描隧道显微镜(PSTM)成像的分辨率和效率。对四种探针,即不镀膜,带菱形金尖,镀金膜有孔径,镀金膜无孔径的探针,用二维p极化波,满足全反射条件,并用样品台上方平行于界面的隐失波作为等效入射波源,用探针距离尖顶一定高度截面的玻印亭矢量计算散射场强。数值模拟结果表明,带纳米尺度金尖的探针具有最好成像的分辨率和效率,镀膜无孔径和镀膜孔径探针次之,不镀膜探针最差。     

光子扫描隧道显微镜研究

光子扫描隧道显微镜（ＰＳＴＭ）是电子扫描隧道显微镜（ＳＴＭ）的光学模拟，它对样品的光学特性特别敏感，且大大突破了传统光学显微镜的衍射极限的限制，是扫描探针显微镜家族中新出现的一个成员，我们自行设计开发了一套ＰＳＴＭ实验系统，研究了其纵向扫描特性，观察了二维干涉光场及其它实际样品。实验表明该实验室系统的扫描面积达１２×１２ｕｍ￣２，纵向分辨率达λ／１００，横向分辨率有待进一步鉴定，从已观察的样品分析不低于０．１ｕｍ。     

Optical near field scattered by surface defects: Two-dimensional numerical analysis

Recently developed scanning near-field optical microscopy has drawn attention to the problem of describing the electromagnetic field in the close vicinity of a surface. In this work, we present a numerical simulation that solves rigorously the field equations for a dielectric-air-dielectric layer system with arbitrary one-dimensional structure at its interfaces. Our theory is applied to calculate the intensity of the near field transmitted at the center of the tip of a probe as it is moved at a constant height above a surface with two identical topographic defects. The effects on the optical image due to the separation of the objects, and the shape difference between the ridges and grooves are discussed. The resolution limit and the conditions for near field interaction are determined. This paper was originally presented at the first Asia-Pacific Workshop on Near Field Optics, which was held on August 17 and 18, 1996 at Seoul Education and Culture Center, Seoul, Korea, organized by Condensed Matter Research Institute, Seoul National University.     

“禁戒光”近场光学显微镜原理与系统

扫描近场光学显微术是８０年代后期发展起来的一种分辨率超过衍射极限的新型光学显微镜技术。本文介绍了国外最近出现的“禁戒光”近场光学显微镜系统的工作原理及结构。透射式ＳＮＯＭ中部分光沿着光轴向前传播；部分光沿着大于全内反射临界角的方向传播。前者称为允许光；后者称为禁戒光。应用“禁戒光”近场光学显微镜可同时获得三幅图像，即允许光像、禁戒光像和反映样品表面形貌的剪切力图像。禁戒光图像能够提供很好的对比度和分辨率。