Abstract

Bright beams such as lasers and synchrotron radiation play a decisive role in opening up new windows for investigating microscopic structures of materials. We have repeatedly developed brighter electron beams since 1968 to utilize the phase information in an electron beam. As it turned out, every time we developed a brighter electron beam, the precision in the phase measurements increased thus opening up new applications. It has become possible to carry out fundamental experiments in quantum mechanics that were once regarded as “thought experiments”. Such experiments include single-electron build-up of an interference pattern and conclusive experiments on the Aharonov-Bohm effect. Also, visualizing magnetic lines of force in h/e flux units by interference microscopy and dynamically visualizing quantized vortices in superconductors by Lorentz microscopy has become possible. In spring 2000, we completed a 1-MV microscope that has the brightest beam ever obtained, and we have begun obtaining various new results on the vortex behaviors inside high-Tc superconductors, such as the observations of vortices trapped along tilted columnar defects in Bi-2212 film and elucidations of the mechanism for forming a special arrangement of vortices, the chain-lattice state, that reflects the layered structure of the material.