title: Nondestructive Measurement of Orbital Angular Momentum for an Electron Beam.
abstract: Free electrons with a helical phase front, referred to as "twisted" electrons, possess an orbital angular momentum (OAM) and, hence, a quantized magnetic dipole moment along their propagation direction. This intrinsic magnetic moment can be used to probe material properties. Twisted electrons thus have numerous potential applications in materials science. Measuring this quantity often relies on a series of projective measurements that subsequently change the OAM carried by the electrons. In this Letter, we propose a nondestructive way of measuring an electron beam's OAM through the interaction of this associated magnetic dipole with a conductive loop. Such an interaction results in the generation of induced currents within the loop, which are found to be directly proportional to the electron's OAM value. Moreover, the electron experiences no OAM variations and only minimal energy losses upon the measurement, and, hence, the nondestructive nature of the proposed technique.
authors: The Max Planck Centre for Extreme and Quantum Photonics, Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada.
authors: Hugo
authors: H
authors: Larocque
authors: The Max Planck Centre for Extreme and Quantum Photonics, Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada.
authors: Frédéric
authors: F
authors: Bouchard
authors: CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena, Italy.
authors: Vincenzo
authors: V
authors: Grillo
authors: The Max Planck Centre for Extreme and Quantum Photonics, Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada.
authors: Alicia
authors: A
authors: Sit
authors: CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena, Italy.|Dipartimento FIM Universitá di Modenae Reggio Emilia, Via G Campi 213/a, I-41125 Modena, Italy.
authors: Stefano
authors: S
authors: Frabboni
authors: Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Jülich 52425, Germany.
authors: Rafal E
authors: RE
authors: Dunin-Borkowski
authors: School of Physics and Astronomy, Glasgow University, Glasgow G12 8QQ, United Kingdom.
authors: Miles J
authors: MJ
authors: Padgett
authors: The Max Planck Centre for Extreme and Quantum Photonics, Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada.|Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
authors: Robert W
authors: RW
authors: Boyd
authors: The Max Planck Centre for Extreme and Quantum Photonics, Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada.|Department of Physics, Institute for Advanced Studies in Basic Sciences, 45137-66731 Zanjan, Iran.
authors: Ebrahim
authors: E
authors: Karimi