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Experimental realization of a π/2 vortex mode converter for electrons using a spherical aberration corrector

Schachinger, T.; Hartel, P.; Lu, P.-H.; Löffler, S.; Obermair, M. 1; Dries, M. 1; Gerthsen, D. 1; Dunin-Borkowski, R. E.; Schattschneider, P.
1 Laboratorium für Elektronenmikroskopie (LEM), Karlsruher Institut für Technologie (KIT)


In light optics, beams with orbital angular momentum (OAM) can be produced by employing a properly-tuned two-cylinder-lens arrangement, also called α/2 mode converter. It is not possible to convey this concept directly to the beam in an electron microscope due to the non-existence of cylinder lenses in commercial transmission electron microscopes (TEMs). A viable work-around are readily-available electron optical elements in the form of quadrupole lenses. In a proof-of-principle experiment in 2012, it has been shown that a single quadrupole in combination with a Hilbert phase-plate produces a spatially-confined, transient vortex mode.
Here, an analogue to an optical α/2 mode converter is realized by repurposing a CEOS DCOR probe corrector in an aberration corrected TEM in a way that it resembles a dual cylinder lens using two quadrupoles. In order to verify the presence of OAM in the output beam, a fork dislocation grating is used as an OAM analyser. The possibility to use magnetic quadrupole fields instead of, e.g., prefabricated fork dislocation gratings to produce electron beams carrying OAM enhances the beam brightness by almost an order of magnitude and delivers switchable high-mode purity vortex beams without unwanted side-bands.

Verlagsausgabe §
DOI: 10.5445/IR/1000136938
Veröffentlicht am 06.09.2021
DOI: 10.1016/j.ultramic.2021.113340
Zitationen: 10
Web of Science
Zitationen: 10
Zitationen: 9
Cover der Publikation
Zugehörige Institution(en) am KIT Laboratorium für Elektronenmikroskopie (LEM)
Universität Karlsruhe (TH) – Zentrale Einrichtungen (Zentrale Einrichtungen)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 0304-3991, 1879-2723
KITopen-ID: 1000136938
Erschienen in Ultramicroscopy
Verlag Elsevier
Band 229
Seiten Art.-Nr.: 113340
Nachgewiesen in Web of Science
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