Realization of a tilted reference wave for electron holography by means of a condenser biprism - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Ultramicroscopy Année : 2016

Realization of a tilted reference wave for electron holography by means of a condenser biprism

Résumé

As proposed recently, a tilted reference wave in off-axis electron holography is expected to be useful for aberration measurement and correction. Furthermore, in dark-field electron holography, it is considered to replace the reference wave, which is conventionally diffracted in an unstrained object area, by a well-defined object-independent reference wave. Here, we first realize a tilted reference wave by employing a biprism placed in the condenser system above three condenser lenses producing a relative tilt magnitude up to 20/nm at the object plane (300 kV). Paraxial ray-tracing predicts condenser settings for a parallel illumination at the object plane, where only one half of the round illumination disc is tilted relative to the optical axis without displacement. Holographic measurements verify the kink-like phase modulation of the incident beam and return the interference fringe contrast as a function of the relative tilt between both parts of the illumination. Contrast transfer theory including condenser aberrations and biprism instabilities was applied to explain the fringe contrast measurement. A first dark-field hologram with a tilted – object-free – reference wave was acquired and reconstructed. A new application for bright/dark-field imaging is presented.
Fichier non déposé

Dates et versions

hal-01404505 , version 1 (28-11-2016)

Identifiants

Citer

Falk Röder, Florent Houdellier, Thibaud Denneulin, Etienne Snoeck, Martin Hÿtch. Realization of a tilted reference wave for electron holography by means of a condenser biprism. Ultramicroscopy, 2016, 161, pp.23 - 40. ⟨10.1016/j.ultramic.2015.11.004⟩. ⟨hal-01404505⟩
109 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More