Toward Single Mode, Atomic Size Electron Vortex Beams

Autor:	Niklas Dellby, Tracy J. Lovejoy, Jan Rusz, Ondrej L. Krivanek, Juan Carlos Idrobo
Rok vydání:	2014
Předmět:	Physics business.industry Aperture Condenser (optics) Single-mode optical fiber Holography Electron law.invention Optics law Scanning transmission electron microscopy Physics::Accelerator Physics business Instrumentation Beam (structure) Monochromator
Zdroj:	Microscopy and Microanalysis. 20:832-836
ISSN:	1435-8115 1431-9276
DOI:	10.1017/s143192761400083x
Popis:	We propose a practical method of producing a single mode electron vortex beam suitable for use in a scanning transmission electron microscope (STEM). The method involves using a holographic “fork” aperture to produce a row of beams of different orbital angular momenta, as is now well established, magnifying the row so that neighboring beams are separated by about 1 µm, selecting the desired beam with a narrow slit, and demagnifying the selected beam down to 1–2 Å in size. We show that the method can be implemented by adding two condenser lenses plus a selection slit to a straight-column cold-field emission STEM. It can also be carried out in an existing instrument, the monochromated Nion high-energy-resolution monochromated electron energy-loss spectroscopy-STEM, by using its monochromator in a novel way. We estimate that atom-sized vortex beams with ≥20 pA of current should be attainable at 100–200 keV in either instrument.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5a682604662de1639770295dc567d91b https://doi.org/10.1017/s143192761400083x Zobrazit plný text záznamu