Development of electron phase microscopes

We have developed electron–optical techniques such as those of bright and coherent electron beams and electron interference systems that have led to the realization of electron phase microscopy. Microscopes using these techniques have been used to carry out fundamental experiments in quantum mechanics once regarded as “Gedanken” experiments, to quantitatively observe magnetic lines of force (or equipotential lines) inside and outside ferromagnetic (or electric) samples in a form of holographic interference microscopy, and to dynamically observe individual magnetic vortices in superconductors by Lorentz microscopy. This paper is dedicated to Professor Kai Siegbahn, who passed away on 20 July 2007.