Hologram simulation for off-axis electron holography

Hologram simulation for electron holography using an electron biprism is de scribed. An electron hologram is superimposed by Fresnel fringes originatin g from the electron biprism, which affects both the amplitude and the phase of the object wave and the reference wave. In this simulation, we consider the effects of Fresnel diffraction as well as the electron-wave phase shif t due to the electromagnetic field produced by the specimen. We also take i nto account the phase shift due to the inner potential of the specimen, the amplitude modulation due to the absorption of the incident electrons by th e specimen, reference-wave distortion caused by the electromagnetic fields, coherency of the electron wave, and quantum noise of the detected electron s. Simulated and experimentally obtained holograms and reconstructed images are compared for the cases of a charged latex spherical particle and a sin gle magnetic-domain spherical particle placed on a carbon film. (C) 2000 El sevier Science B.V. All rights reserved.