Quantum tornado in the electron beam

Quantum tornado in the electron beam
http://www.nanowerk.com/news/newsid=18071.php

(Nanowerk News) Manipulating materials with rotating quantum particles: a team from the University of Antwerp and TU Vienna (Professor Peter Schattschneider, Institute of Solid State Physics) has succeeded in producing what are known as vortex beams: rotating electron beams, which make it possible to investigate the magnetic properties of materials. In the future, it may even be possible to manipulate the tiniest components in a targeted manner and set them in rotation. The physicists report on this breakthrough in electron physics and its application in the current edition of Nature ("Production and application of electron vortex beams").
Rotating current: the quantum tornado
Electron beams have been used to analyse materials for some time now – for example in electron microscopes. For the most part, the beams' rotation does not affect this analysis. In classical physics, an electron current in a vacuum does not have any orbital angular momentum. In quantum mechanics, however, the electrons must be envisaged as a wavelike current – which can rotate as a whole about its propagation direction, similar to the air flow in a tornado.

A flat wave (left) meets the specially shaped grid screen, which converts the electron beam into right-rotating and left-rotating vortex beams (top and bottom), and a middle beam that does not rotate. Similar to in a tornado, the rotation of the electron current is low internally


Vortex light beams have been used in optics for some time (for example, as optical tweezers for manipulating small particles). Vortex beams made from electrons also offer many new possibilities for managing nanoparticles or measuring angular momentum-related parameters. However, there were previously no really efficient methods of producing them. "When I was working on an idea of how these beams could be technically produced, it emerged that colleagues from Antwerp had had the same idea", explains Prof Schattschneider. "We therefore decided to pursue the project together: Antwerp had progressed further with the production and Vienna came up with a suggestion for the first application."

The trick with the screen

The production of vortex electron beams was made possible with the help of a grid-like screen cut from platinum foil. When it passes through the platinum screen, the electron beam is diffracted in a similar way to light beams when they pass through a fine grid. The shape of this screen, which measures only a few millionths of a metre, was specifically calculated so that a flat incident electron wave is converted into vortex beams. Right-rotating and left-rotating vortex beams are thus formed behind the grid and in the middle there is a conventional electron beam that does not rotate.

If the electrons are used to irradiate a material which for its part also influences the angular momentum of the electrons, and if the electrons are subsequently directed through the made-to-measure platinum screen, then, after this, either the right-rotating or the left-rotating vortex beam will be more intense. "This enables us to investigate processes affected by angular momentum in nanomaterials much more precisely than was previously possible", explains Prof Schattschneider.
Better than science fiction
The physicist, who also occasionally writes science fiction, does not find it hard to imagine more exotic applications for the vortex beams: "These electron beams could be used in a targeted way to set tiny wheels in motion on a microscopic motor. Also, the magnetic field of the rotating electrons could be used in the tiniest length scales", Schattschneider speculates. Even applications in data transfer (quantum cryptography) and quantum computers are feasible.
Source: Vienna University of Technology

Orbital angular momentum in radio: Measurement methods

Orbital angular momentum in radio: Measurement methods
Authors:
Mohammadi, Siavoush M.; Daldorff, Lars K. S.; Forozesh, Kamyar; Thidé, Bo; Bergman, Jan E. S.; Isham, Brett; Karlsson, Roger; Carozzi, T. D.
Affiliation:
AA(Department of Electrical and Computer Engineering, Interamerican University of Puerto Rico, Bayamón, Puerto Rico); AB(Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden); AC(Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden); AD(Swedish Institute of Space Physics, Uppsala, Sweden); AE(Swedish Institute of Space Physics, Uppsala, Sweden); AF(Department of Electrical and Computer Engineering, Interamerican University of Puerto Rico, Bayamón, Puerto Rico); AG(Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden); AH(Department of Physics and Astronomy, University of Glasgow, Glasgow, UK)
Publication:
Radio Science, Volume 45, Issue 4, CiteID RS4007 (RaSc. Homepage)
Publication Date:
07/2010
Origin:
AGU
AGU Keywords:
Radio Science: Radio wave propagation, Radio Science: Instruments and techniques (1241), Radio Science: Radio astronomy
Abstract Copyright:
(c) 2010: American Geophysical Union
DOI:
10.1029/2009RS004299
Bibliographic Code:
2010RaSc...45S4007M

Orbital Angular Momentum – Bo Thide and Jan Bergman (SETI Talks)

Link to SETI Archive: seti.org On the extraction of all information embedded in radio siganls: Implications for SETI: A new idea for utilizing all of the information in photons for communication involves a little-know electromagnetic property: the photon’s orbital angular momentum (POAM). The communication and computer industries are actively looking at the possibilities. We will discuss current research and the implications for SETI.



http://ufo-tv.com/orbital-angular-momentum-bo-thide-and-jan-bergman-seti-talks

Generation of electron beams carrying orbital angular momentum

Generation of electron beams carrying orbital angular momentum

Nature 464, 737 (2010). doi:10.1038/nature08904

Authors: Masaya Uchida & Akira Tonomura
All forms of waves can contain phase singularities. In the case of optical waves, a light beam with a phase singularity carries orbital angular momentum, and such beams have found a range of applications in optical manipulation, quantum information and astronomy. Here we report the generation of an electron beam with a phase singularity propagating in free space, which we achieve by passing a plane electron wave through a spiral phase plate constructed naturally from a stack of graphite thin films. The interference pattern between the final beam and a plane electron wave in a transmission electron microscope shows the ‘Y’-like defect pattern characteristic of a beam carrying a phase singularity with a topological charge equal to one. This fundamentally new electron degree of freedom could find application in a number of research areas, as is the case for polarized electron beams.

Link: http://feeds.nature.com/~r/nature/rss/current/~3/fny431UlOME/nature08904
Author: Masaya Uchida

NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY USING LIGHT WITH ORBITAL ANGULAR MOMENTUM

http://www.wipo.int/pctdb/ja/ia.jsp?ia=IB2009%2F050145&IA=IB2009050145&DISPLAY=DESC

NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY USING LIGHT WITH ORBITAL ANGULAR MOMENTUM

FIELD OF THE INVENTION The present invention relates to a sample analysis method based on nuclear magnetic resonance (NMR) spectroscopy. The invention also relates to a corresponding computer program product and device for carrying out the method.
....

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a method of analyzing a sample consisting of molecules, the analysis being based upon nuclear magnetic resonance spectroscopy, the method comprising the following steps:

- turning on a light source;

- introducing orbital angular momentum into the light;

- obtaining a focused light beam carrying orbital angular momentum; sequentially illuminating the sample with the focused light beam carrying orbital angular momentum for obtaining nuclear magnetic polarizability of the sample; and

- obtaining a free induction decay signal resulting from the illumination, the free induction decay signal carrying characteristics of the sample.

This provides clear advantages, namely for instance the obtained free induction decay (FID) signal is much stronger than the corresponding signal obtained by using traditional NMR spectroscopy methods. Thus, the sensitivity of the measurement technique is greatly improved. The obtained FID signal is also less noisy and better resolution can be achieved. As a consequence smaller samples can be analyzed.

According to a second aspect of the invention there is provided a computer program product comprising instructions for implementing the method according the first aspect of the invention when loaded and run on computer means of an analysis device.

Superposition of helical beams by using a Michelson interferometer

Superposition of helical beams by using a Michelson interferometer

Chunqing Gao, Xiaoqing Qi, Yidong Liu, and Horst Weber

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-18-1-72

Orbital Angular Momentum in Radio - A System Study

Orbital Angular Momentum in Radio - A System Study

Mohammadi, S. M. Daldorff, L. K. S. Bergman, J. E. S. Karlsson, R. L. Thide, B. Forozesh, K. Carozzi, T. D. Isham, B.

This paper appears in: Antennas and Propagation, IEEE Transactions on
Accepted for future publication
ISSN: 0018-926X
Abstract
Recent discoveries concerning rotating (helical) phase fronts and orbital angular momentum (OAM) of laser beams are applied to radio frequencies and comprehensive simulations of a radio OAM system are performed. We find that with the use of vector field-sensing electric and magnetic triaxial antennas, it is possible to unambiguously estimate the OAM in radio beams by local measurements at a single point, assuming ideal (noiseless) conditions and that the beam axis is known. Furthermore, we show that conventional antenna pattern optimization methods can be applied to OAM-generating circular arrays to enhance their directivity.

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