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The propagation of electron beams carrying angular momentum in crystals is studied using a multislice approach for the model system Fe. It is found that the vortex beam is distorted strongly due to elastic scattering. Consequently, the…

Materials Science · Physics 2013-04-09 Stefan Löffler , Peter Schattschneider

Several experimental groups have recently obtained the so called vortex electrons (electrons with orbital angular momentum (OAM) of l = 100h) with energies of 300 keV. The gyromagnetic ratio of such electrons becomes proportional to the OAM…

Accelerator Physics · Physics 2014-10-16 Anatoly S. Konkov , Alexander P. Potylitsyn , Marina S. Polonskaya

This paper is devoted to study the propagation of light beams carrying orbital angular momentum in optically anisotropic media. We first review some properties of homogeneous anisotropic media, and describe how the paraxial formalism is…

Optics · Physics 2015-05-28 Antonio Picón , Albert Benseny , Jordi Mompart , Gabriel F. Calvo

Free electron beams that carry high values of orbital angular momentum (OAM) possess large magnetic moments along the propagation direction. This makes them an ideal probe for measuring the electronic and magnetic properties of materials,…

Motivated by the recent discovery of electron vortex beams carrying orbital angular momentum (AM), we construct exact Bessel-beam solutions of the Dirac equation. They describe relativistic and nonparaxial corrections to the scalar electron…

Quantum Physics · Physics 2011-10-18 Konstantin Y. Bliokh , Mark R. Dennis , Franco Nori

Angular momentum and torque are important principles for basic and applied physics on any spatial scales, for example, in elementary particles, cold gases, optical tweezers, quantum information technology, metamaterials, gyroscopes or…

Optics · Physics 2024-12-16 Y. Fang , J. Kuttruff , P. Baum

We set forth a method to analyze the orbital angular momentum of a light field. Instead of using the canonical formalism for the conjugate pair angle-angular momentum, we model this latter variable by the superposition of two independent…

Quantum Physics · Physics 2013-12-20 L. L. Sanchez-Soto , A. B. Klimov , P. de la Hoz , I. Rigas , J. Rehacek , Z. Hradil , G. Leuchs

Manifestations of orbital angular momentum induced effects in the diffraction of a radially polarized vector beam by an off-axis tilted aperture are studied both experimentally and theoretically. Experiments were carried out to extract the…

We present generalized expressions to calculate the orbital angular momentum for invariant beams using scalars potentials. The solutions can be separated into transversal electric TE, transversal magnetic TM and transversal electromagnetic…

Optics · Physics 2020-08-11 Irving Rondon , Francisco Soto-Eguibar

The transverse beam pattern, usually observed in experiment, is a result of averaging the optical-frequency oscillations of the electromagnetic field distributed over the beam cross section. An analytical criterion is derived that these…

Optics · Physics 2015-05-13 A. Ya. Bekshaev

We propose a reconstruction of vortex beams based on the implementation of quadratic transformations in the orbital angular momentum. The information is encoded in a superposition of Bessel-like nondiffracting beams. The measurement of the…

Optics · Physics 2015-05-18 J. Rehacek , Z. Hradil , Z. Bouchal , A. B. Klimov , I. Rigas , L. L. Sanchez-Soto

Optical vortex beams carry orbital angular momentum and thus exert torque on illuminated objects. A dielectric microtool - a microbarbell - is used in a two-laser optical tweezers to measure the torque of a focused optical vortex. The tool…

Measuring the orbital angular momentum (OAM) of vortex beams, including the magnitude and the sign, has great application prospects due to its theoretically unbounded and orthogonal modes. Here, the sign-distinguishable OAM measurement in…

Quantum Physics · Physics 2020-11-19 Zhucheng Zhang , Jiancheng Pei , Yi-Ping Wang , Xiaoguang Wang

Recently, a new device to measure the Orbital Angular Momentum (OAM) electronic spectrum after elastic/inelastic scattering in a transmission electron microscope has been introduced. We modified the theoretical framework needed to describe…

Instrumentation and Detectors · Physics 2020-05-28 Matteo Zanfrognini , Enzo Rotunno , Stefano Frabboni , Alicia Sit , Ebrahim Karimi , Ulrich Hohenester , Vincenzo Grillo

Characterizing the orbital angular momentum (OAM) of a vortex beam is critically important for OAM-encoded data transfer. However, in typical OAM-based applications where vortex beams transmit through diffusers, the accompanying scattering…

In this work we present an alternative way to look at electron diffraction in a transmission electron microscope. In stead of writing the scattering amplitude in Fourier space as a set of plane waves, we use the cylindrical Fourier…

Instrumentation and Detectors · Physics 2015-11-13 Roeland Juchtmans , Jo Verbeeck

Photons carry one unit of angular momentum associated with their spin~\cite{Beth1936}. Structured vortex beams carry additional orbital angular momentum which can also be transferred to matter~\cite{Allen1992}. This extra twist has been…

Vortex $\gamma$ photons carrying orbital angular momenta (OAM) hold great potential for various applications. However, their generation remains a great challenge. Here, we successfully generate sub-MeV vortex $\gamma$ photons via…

For paraxial and non-paraxial light, numerous measures of electromagnetic attribute are expressible in terms of photon annihilation and creation. Accordingly, energy, angular momentum and chirality measures acquire a consistent…

Optics · Physics 2018-02-14 Matt M. Coles , David L. Andrews

In a Nature LETTER [1], a control of neutron angular momentum was apparently demonstrated using a neutron crystal interferometer. In the meantime, a number of highly interesting articles have been published dealing with the n-OAM and…

Quantum Physics · Physics 2023-09-08 Wolfgang Treimer , Frank Haußer , Martin Suda