Dynamic observation of surface atom movement using high-speed image processing CCD video camera

摘要

Real-time observation of spherical aberration-free phase image with a high resolution transmission electron microscope is a powerful technique for understanding surface and interface phenomena at an atomic level. A real-time defocus-image modulation processing electron microscope (DIMP-EM) is one of the most promising approaches to realize the real-time spherical aberration-free phase observation for high resolution electron microscopy. DIMP is based on an integration of through-focus images multiplied with a specific bipolar (i.e. having both positive and negative values) weight function that represents the characteristics of the electron optical system. In the real-time DIMP-EM, two respective images multiplied by the positive or the negative weight function have to be obtained separately and subtracted from each other in one video field period (1/60th of a second). A newly developed high-speed image processing CCD video camera enables integration of both weighted images in a period of one video field (1/60s) and continuously output the subtracted image as an NTSC video signal. In the present paper, we report experimental results for real-time spherical aberration-free observation of surface atoms using the real-time DIMP-EM combined with the high-speed image processing CCD video camera.