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Experimental Demonstration of an Electrostatic Orbital Angular Momentum Sorter for Electron Beams

Amir H. Tavabi1, Paolo Rosi2, Enzo Rotunno3,*, Alberto Roncaglia4, Luca Belsito4, Stefano Frabboni2,3, Giulio Pozzi1,5, Gian Carlo Gazzadi3, Peng-Han Lu1,6 et al.

Robert Nijland7, Moumita Ghosh7, Peter Tiemeijer7, Ebrahim Karimi8, Rafal E. Dunin-Borkowski1, and Vincenzo Grillo3,†

  • 1Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
  • 2Dipartimento FIM, Universitá di Modena e Reggio Emilia, 41125 Modena, Italy
  • 3Centro S3, Istituto di Nanoscienze—CNR, 41125 Modena, Italy
  • 4Istituto per la Microelettronica e i Microsistemi-CNR, 40129 Bologna, Italy
  • 5Department of Physics and Astronomy, University of Bologna, 40127 Bologna, Italy
  • 6RWTH Aachen University, 52074 Aachen, Germany
  • 7Thermo Fisher Scientific, PO Box 80066, 5600 KA Eindhoven, Netherlands
  • 8Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada

  • *Corresponding author. enzo.rotunno@cnr.it
  • †Corresponding author. vincenzo.grillo@cnr.it
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Phys. Rev. Lett. 126, 094802 – Published 5 March, 2021

DOI: https://doi.org/10.1103/PhysRevLett.126.094802

Abstract

The component of orbital angular momentum (OAM) in the propagation direction is one of the fundamental quantities of an electron wave function that describes its rotational symmetry and spatial chirality. Here, we demonstrate experimentally an electrostatic sorter that can be used to analyze the OAM states of electron beams in a transmission electron microscope. The device achieves postselection or sorting of OAM states after electron-material interactions, thereby allowing the study of new material properties such as the magnetic states of atoms. The required electron-optical configuration is achieved by using microelectromechanical systems technology and focused ion beam milling to control the electron phase electrostatically with a lateral resolution of 50 nm. An OAM resolution of 1.5ℏ is realized in tests on controlled electron vortex beams, with the perspective of reaching an optimal OAM resolution of 1ℏ in the near future.

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Outline

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Phys. Rev. Lett. 126, 094802– Published 5 March, 2021
  • Received 29 September 2020
  • Revised 6 December 2020
  • Accepted 12 January 2021
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