Genz Florian, Niermann Tore, Buijsse Bart, Freitag Bert, Lehmann Michael
Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni, 10623 Berlin, Germany.
Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni, 10623 Berlin, Germany.
Ultramicroscopy. 2014 Dec;147:33-43. doi: 10.1016/j.ultramic.2014.06.002. Epub 2014 Jun 23.
The optimum biprism position as suggested by Lichte (Ultramicroscopy 64 (1996) 79 [10]) was implemented into a state-of-the-art transmission electron microscope. For a setup optimized for atomic resolution holograms with a width of 30nm and a fringe spacing of 30pm, we investigated the practical improvements on hologram quality. The setup is additionally supplemented by a second biprism as suggested by Harada et al. (Applied Physics Letters 84 (2004) 3229 [12]). In order to estimate the possibilities and limitations of the double biprism setup, geometric optics arguments lead to calculation of the exploitable shadow width, necessary for strong reduction of biprism-induced artefacts. Additionally, we used the double biprism setup to estimate the biprism vibration, yielding the most stable imaging conditions with lowest overall fringe contrast damping. Electron holograms of GaN demonstrate the good match between experiment and simulation, also as a consequence of the improved stability.
