Electron holography

from Wikipedia, the free encyclopedia

Electron holography is a method of electron microscopy with which extremely high resolutions can be achieved.

Working method

The picture shows the electron hologram of a latex ball on a carbon substrate, which is covered with gold particles (small dark dots), in the lower part of the picture there is a vacuum. The biprism lies roughly above the vacuum edge; parallel to this, the phase surfaces of the interferogram can be seen, which is superimposed on the classic image and is the carrier of the phase information.

In electron holography, the electron beam is split into two partial beams with an electric biprism . A partial beam penetrates the examination object, the other partial beam continues undisturbed. The two partial beams combine on the screen to form an interference pattern , the electron hologram . This contains all information of the electron wave. With the help of a computer, the amplitude and phase can be reconstructed and the complex image wave is obtained. This can be displayed as a phase image or an amplitude image.

High resolution

The method can be used for high-resolution transmission electron microscopy . For this purpose, the image errors caused by the magnetic lenses are calculated out numerically.

literature

  • Eduard Heindl : Use of neural networks in electron holography . Dissertation. Eberhard Karls University, Tübingen 2001. ( online , PDF, 3.62 MB)