1,003 research outputs found
Quantum optical coherence tomography of a biological sample
Quantum optical coherence tomography (QOCT) makes use of an entangled-photon
light source to carry out dispersion-immune axial optical sectioning. We
present the first experimental QOCT images of a biological sample: an
onion-skin tissue coated with gold nanoparticles. 3D images are presented in
the form of 2D sections of different orientations.Comment: 16 Pages, 6 Figure
Imaging of the Breast
Early detection of breast cancer combined with targeted therapy offers the best outcome for breast cancer patients. This volume deal with a wide range of new technical innovations for improving breast cancer detection, diagnosis and therapy. There is a special focus on improvements in mammographic image quality, image analysis, magnetic resonance imaging of the breast and molecular imaging. A chapter on targeted therapy explores the option of less radical postoperative therapy for women with early, screen-detected breast cancers
Wave dynamics in a sunspot umbra
The high spatial and time resolution data obtained with SDO/AIA for the
sunspot in active region NOAA 11131 on 08 December 2010 were analysed with the
time-distance plot technique and the pixelised wavelet filtering method.
Oscillations in the 3 min band dominate in the umbra. The integrated spectrum
of umbral oscillations contains distinct narrowband peaks at 1.9 min, 2.3 min,
and 2.8 min. The power significantly varies in time, forming distinct
oscillation trains. The oscillation power distribution over the sunspot in the
horizontal plane reveals that the enhancements of the oscillation amplitude, or
wave fronts, have a distinct structure consisting of an evolving two-armed
spiral and a stationary circular patch at the spiral origin, situated near the
umbra centre. This structure is seen from the temperature minimum to the
corona. In time, the spiral rotates anti-clockwise. The wave front spirality is
most pronounced during the maximum amplitude phases of the oscillations. In the
low-amplitude phases the spiral breaks into arc-shaped patches. The 2D
cross-correlation function shows that the oscillations at higher atmospheric
levels occur later than at lower layers. The phase speed is estimated to be
about 100 km/s. The fine spectral analysis shows that the central patch
corresponds to the high-frequency oscillations, while the spiral arms highlight
the lower-frequency oscillations in the 3-min band. The vertical and horizontal
radial structure of the oscillations is consistent with the model that
interprets umbral oscillations as slow magnetoacoustic waves filtered by the
atmospheric temperature non-uniformity in the presence of the magnetic field
inclination from the vertical. The mechanism for the polar-angle structure of
the oscillations, in particular the spirality of the wave fronts, needs to be
revealed.Comment: 8 pages, 9 figures, Astronomy and Astrophysics, 201
Roadmap on superoscillations
Superoscillations are band-limited functions with the counterintuitive property that they can vary arbitrarily faster than their fastest Fourier component, over arbitrarily long intervals. Modern studies originated in quantum theory, but there were anticipations in radar and optics. The mathematical understanding—still being explored—recognises that functions are extremely small where they superoscillate; this has implications for information theory. Applications to optical vortices, sub-wavelength microscopy and related areas of nanoscience are now moving from the theoretical and the demonstrative to the practical. This Roadmap surveys all these areas, providing background, current research, and anticipating future developments
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