Phase Plate STEM

Abstract

It is difficult to obtain high-contrast images for biological materials because of the weak interaction between the electron waves and the specimens. Therefore, the phase contrast is enhanced by defocusing an objective lens at the cost of the spatial resolution. We developed phase plate scanning transmission electron microscopy (P-STEM). It is a high contrast imaging method of phase objects without losing spatial resolution under the in-focus condition. In this paper the optical principles of P-STEM is introduced.