Manipulation of an atomic beam by a computer-generated hologram
Article Abstract:
A Fourier hologram is used to diffract atomic beams in specific interference patterns. In the future, this process may be refined to precisely manipulate ultra-cold atoms. In the process, a beam of ultra-cold metastable neon atoms is passed through a computer generated hologram. The hologram, containing a 100-nanometer-thick silicon nitride membrane, encodes the Fourier transform of the required atomic pattern. The far-field pattern of the diffracted wave generates an image of the object when the hologram is illuminated with a plane wave. The use of the technique with other manipulation techniques will enable the reproduction of real-time moving patterns of atoms.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Mammary models: Clinicians screening patients for diseases such as breast cancer have to let a machine do much of the seeing for them. Theoretical modelling of the processes involved can help to ensure that reliable images are generated
Article Abstract:
Clinicians and technicians using machine-generated images may not be aware of the mathematics behind image processing. X-ray mammography suffers problems not reliably solved by stock imaging packages. There is often poor signal-to-noise ratio, signs of critical microcalcifications may be lost and definition is blurred by scattering of x-ray photons. The problems are being approached by Michael Brady and Ralph Highnam of the Department of Engineering Science at the University of Oxford. They are building a sophisticated model of the physics of x-rays able to closely simulate actual images, filter out noise and augment zones of interest.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Holography with X-rays
Article Abstract:
Gabor in 1948 first recommended the use of holography in characterizing atomic configurations of solids. The use of local source X-ray holography eliminated the dimension problem in ordinary X-ray diffractions by allowing the diffused wave components to interfere with a fluorescent reference wave thereby giving an exact structural arrangement. The first X-ray hologram and its derived atomic image were shown in the study by Tegze and Faigel where one perovskite SrTiO3 crystal was subjected to a standard X-ray source.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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