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Computational time-reversal imaging with a small number of random and noisy measurements  [PDF]
M. Andrecut
Physics , 2009,
Abstract: Computational time reversal imaging can be used to locate the position of multiple scatterers in a known background medium. The current methods for computational time reversal imaging are based on the null subspace projection operator, obtained through the singular value decomposition of the frequency response matrix. Here, we discuss the image recovery problem from a small number of random and noisy measurements, and we show that this problem is equivalent to a randomized approximation of the null subspace of the frequency response matrix.
Quantum Imaging with Incoherent Photons  [PDF]
C. Thiel,T. Bastin,J. Martin,E. Solano,J. von Zanthier,G. S. Agarwal
Physics , 2007, DOI: 10.1103/PhysRevLett.99.133603
Abstract: We propose a technique to obtain sub-wavelength resolution in quantum imaging with potentially 100% contrast using incoherent light. Our method requires neither path-entangled number states nor multi-photon absorption. The scheme makes use of N photons spontaneously emitted by N atoms and registered by N detectors. It is shown that for coincident detection at particular detector positions a resolution of \lambda / N can be achieved.
Quantum Imaging with Undetected Photons  [PDF]
Gabriela B. Lemos,Victoria Borish,Garrett D. Cole,Sven Ramelow,Radek Lapkiewicz,Anton Zeilinger
Physics , 2014, DOI: 10.1038/nature13586
Abstract: Indistinguishable quantum states interfere, but the mere possibility of obtaining information that could distinguish between overlapping states inhibits quantum interference. Quantum interference imaging can outperform classical imaging or even have entirely new features. Here, we introduce and experimentally demonstrate a quantum imaging concept that relies on the indistinguishability of the possible sources of a photon that remains undetected. Our experiment uses pair creation in two separate down-conversion crystals. While the photons passing through the object are never detected, we obtain images exclusively with the sister photons that do not interact with the object. Therefore the object to be imaged can be either opaque or invisible to the detected photons. Moreover, our technique allows the probe wavelength to be chosen in a range for which suitable sources and/or detectors are unavailable. Our experiment is a prototype in quantum information where knowledge can be extracted by and about a photon that is never detected.
Possibility of single biomolecular imaging with coherent amplification of weak scattering X-ray photons  [PDF]
Tsumoru Shintake
Physics , 2008, DOI: 10.1103/PhysRevE.78.041906
Abstract: The number of photons available by coherent X-ray scattering from a single biomolecule is considerably less because of the extremely small elastic-scattering cross-section and low damage threshold. Even with a high X-ray flux of 3 x 10to 12 photons per 100-nm-diameter spot and an ultrashort pulse of 10 fs driven by a future X-ray free electron laser (X-ray FEL), it has been predicted that only a few 100 photons will be available by scattering from a single lysozyme molecule. In this paper I propose a new method: instead of directly observing the photons scattered from the sample, we amplify the scattered waves by superimposing an intense coherent reference pump wave on it and record the resulting interference pattern using a planar X-ray detector, similar to technique followed in holography. Using a nanosized gold particle as a reference pump wave source, we can collect 10 to 4 ~ 10 to 5 photons in single shot imaging where the signal from a single biomolecule is amplified and recorded as 2D diffraction intensity data. To recover the phase information and reconstruct the image, the iterative phase retrieval technique will be applicable. However, the technical difficulty is how to precisely reconstruct faint image of the single bio-molecular in Angstrom resolution, whose intensity is much lower than the bright gold particle linked to it. In order to solve this problem, I propose a new scheme that combines the iterative phase-retrieval on reference pump wave and digital Fourier transform holography.
Is the number of Photons a Classical Invariant?  [PDF]
J. E. Avron,E. Berg,D. Goldsmith,A. Gordon
Physics , 1998, DOI: 10.1088/0143-0807/20/3/304
Abstract: We describe an apparent puzzle in classical electrodynamics and its resolution. It is concerned with the Lorentz invariance of the classical analog of the number of photons.
Classical Radiation of a Finite Number of Photons  [PDF]
L. Stodolsky
Physics , 2002,
Abstract: Under certain conditions the number of photons radiated classically by a charged particle following a prescribed trajectory can be finite. An interesting formula for this number is presented and discussed.
Experimental Comparison of the High-Speed Imaging Performance of an EM-CCD and sCMOS Camera in a Dynamic Live-Cell Imaging Test Case  [PDF]
Hope T. Beier, Bennett L. Ibey
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0084614
Abstract: The study of living cells may require advanced imaging techniques to track weak and rapidly changing signals. Fundamental to this need is the recent advancement in camera technology. Two camera types, specifically sCMOS and EM-CCD, promise both high signal-to-noise and high speed (>100 fps), leaving researchers with a critical decision when determining the best technology for their application. In this article, we compare two cameras using a live-cell imaging test case in which small changes in cellular fluorescence must be rapidly detected with high spatial resolution. The EM-CCD maintained an advantage of being able to acquire discernible images with a lower number of photons due to its EM-enhancement. However, if high-resolution images at speeds approaching or exceeding 1000 fps are desired, the flexibility of the full-frame imaging capabilities of sCMOS is superior.
Quantum entanglement of a large number of photons  [PDF]
H. S. Eisenberg,G. Khoury,G. A. Durkin,C. Simon,D. Bouwmeester
Physics , 2004, DOI: 10.1103/PhysRevLett.93.193901
Abstract: A bipartite multiphoton entangled state is created through stimulated parametric down-conversion of strong laser pulses in a nonlinear crystal. It is shown how detectors that do not resolve photon number can be used to analyze such multiphoton states. Entanglement of up to 12 photons is detected using both the positivity of the partially transposed density matrix and a newly derived criteria. Furthermore, evidence is provided for entanglement of up to 100 photons. The multi-particle quantum state is such that even in the case of an overall photon collection and detection efficiency as low as a few percent, entanglement remains and can be detected.
On the Spectrum of Field Quadratures for a Finite Number of Photons  [PDF]
Emilio Pisanty,Eduardo Nahmad-Achar
Mathematics , 2011, DOI: 10.1088/1751-8113/45/39/395303
Abstract: The spectrum and eigenstates of any field quadrature operator restricted to a finite number $N$ of photons are studied, in terms of the Hermite polynomials. By (naturally) defining \textit{approximate} eigenstates, which represent highly localized wavefunctions with up to $N$ photons, one can arrive at an appropriate notion of limit for the spectrum of the quadrature as $N$ goes to infinity, in the sense that the limit coincides with the spectrum of the infinite-dimensional quadrature operator. In particular, this notion allows the spectra of truncated phase operators to tend to the complete unit circle, as one would expect. A regular structure for the zeros of the Christoffel-Darboux kernel is also shown.
Radionuclide Small Intestine Imaging  [PDF]
Jiri Dolezal,Marcela Kopacova
Gastroenterology Research and Practice , 2013, DOI: 10.1155/2013/861619
Abstract: The aim of this overview article is to present the current possibilities of radionuclide scintigraphic small intestine imaging. Nuclear medicine has a few methods—scintigraphy with red blood cells labelled by means of for detection of the source of bleeding in the small intestine, Meckel’s diverticulum scintigraphy for detection of the ectopic gastric mucosa, radionuclide somatostatin receptor imaging for carcinoid, and radionuclide inflammation imaging. Video capsule or deep enteroscopy is the method of choice for detection of most lesions in the small intestine. Small intestine scintigraphies are only a complementary imaging method and can be successful, for example, for the detection of the bleeding site in the small intestine, ectopic gastric mucosa, carcinoid and its metastasis, or inflammation. Radionuclide scintigraphic small intestine imaging is an effective imaging modality in the localisation of small intestine lesions for patients in whom other diagnostic tests have failed to locate any lesions or are not available. 1. Introduction The aim of this paper is to present current possibilities of radionuclide scintigraphic small intestine imaging. Nuclear medicine has a few methods—scintigraphy with red blood cells (RBCs) labelled by means of for detection of the source of bleeding in the small intestine, Meckel’s diverticulum scintigraphy for detection of the ectopic gastric mucosa, somatostatin receptor scintigraphy for carcinoid imaging, and radionuclide inflammation imaging. Radionuclide scintigraphic small intestine imaging is an effective imaging modality in the localisation of small intestine lesions for patients in whom other diagnostic tests have failed to locate any lesions or are not available. To improve sensitivity, specificity, and location of the area of increased radioactivity abdomen SPECT/CT and PET/CT are recommended. The hybrid SPECT/CT (single-photon emission computed tomography/computed tomography) and PET/CT (positron emission tomography/computed tomography) of the abdomen allow true three-dimensional (3D) image acquisition and display, while at the same time improving the imaging interpretation and accuracy of scintigraphy. Reconstruction of cross-sectional slices uses filtered back or iterative projection. 2. Scintigraphy with Radiolabeled Red Blood Cells Effective and prompt therapy for acute gastrointestinal (GI) bleeding depends on accurate localisation of the site of haemorrhage. Anamnesis and clinical examination can often distinguish upper and lower GI bleeding. Upper GI tract and colon haemorrhage can be confirmed
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