Construction of scanning transmission optical microscope with aberration correction for convergent imaging system by the use of image processing

本研究是在“利用主动图像处理方法校正成像系统的像差”的理论和实验研究的基础上，在过去约十年的科研资助下进行的。本研究的主要目的是建立用于透射扫描显微镜的无像差相位显微镜，作为上述像差校正理论的延伸。第二个目标是设计和构建无像差扫描透射显微镜的原型模型，以确定在探头尺寸限制下实现更高分辨率的无像差成像。基于这些目的，本研究第一阶段（1999）以“互易定理”为基础，从传统透射显微镜的三维成像理论出发，发展了扫描透射显微镜的三维成像理论。利用现有的扩展三维成像理论，设计了扫描透射显微镜无像差成像的计算机模拟，并在第一阶段进行了程序编码。该阶段也开始了无像差扫描透射显微镜原型模型的系统设计和程序编码（1999）。针对以激光扫描显微镜为基础的视频电子电路重建困难的原因，重新设计了原型系统，使其配备固定的二维探测器阵列，而不是快速考虑的单个移动探测器。但是，这种重新设计导致了非常长的图像采集时间，对于256 × 256像素的图像，大约需要一天的时间。原型建造在下一阶段（2000年）进行。对该系统进行了初步的图像采集。然而，由于激光光源缺乏长时间的强度稳定性，观测到的图像非常差。此外，还发现了AO调制器光探头扫描引起的波前改变的迹象，这是本研究应避免的。目前这个问题还没有解决。我们现在正在计划重新设计，例如为这个原型增加光源稳定器和使用机械样品扫描单元。另一方面，对无像差成像的模拟结果清楚地显示出在探头尺寸限制下的更高分辨率。除了光学扫描显微镜外，这种无像差成像技术在透射扫描电子显微镜上的应用是非常有希望的。少

The present study is based on results of the theoretical and experimental studies related to 'Aberration correction of imaging systems using active image processing method', under the support of past Grant-in-aid for scientific research for about ten years. The main aim of this study is the establishment of the aberration-free phase microscopy for transmission scanning microscopes, as an extension of the above aberration correction theory. And the second aim is the design and the construction of a prototype model of the aberration-free scanning transmission microscope to confirm the aberration-free imaging which realized the higher resolution over the probe size limit.According to these aims, the tree dimensional (3D) imaging theory for the scanning transmission microscope was developed from the 3D imaging theory for the conventional transmission microscope, under the basis of the 'reciprocity theorem' in the first stage (1999) of this study. Using the present extended 3D imaging theor … More y, computer simulations of the aberration-free imaging for the scanning transmission microscope was planned, and the program coding was begun in the first stage. The system design and program coding of the prototype model of the aberration-free scanning transmission microscope were also begun in this stage (1999). By the reason of difficulties on the reconstruction of the video electronic circuits in the laser scanning microscope used as the base, the prototype system was re-designed to equip fixed a 2D detector array instead of the single movable detector considered at fast. However, this re-design results in very long image acquisition time of about one day, for 256 x 256 pixels image.The prototype construction was carried out in the next stage (2000). Preliminary image acquisition was made for this system. The observed image was, however, very poor because of the lack of long time intensity stability of the HeNe laser light source. A sign of the wave front alteration due to the light probe scanning by AO modulator was also found, which should be avoided in this study. At present, this problem remains unsolved. We are now planning the re-design such as the addition of the light source stabilizer and the use of mechanical sample scanning unit for this prototype.On the other hand, the result on the simulation of aberration-free imaging clearly shows the higher resolution over the probe size limit as expected. Application of this aberration-free imaging technique to the transmission scanning electron microscope is highly desired in the near future, in addition to the optical scanning microscope. Less