Browsing by Author "Tada, Yoshitaka"

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    Quantitative phase imaging with scanning holographic microscopy: an experimental assessment
    Indebetouw, Guy J.; Tada, Yoshitaka; Leacock, John (2006-11-28)
    This paper demonstrates experimentally how quantitative phase information can be obtained in scanning holographic microscopy. Scanning holography can operate in both coherent and incoherent modes, simultaneously if desired, with different detector geometries. A spatially integrating detector provides an incoherent hologram of the object's intensity distribution (absorption and/or fluorescence, for example), while a point detector in a conjugate plane of the pupil provides a coherent hologram of the object's complex amplitude, from which a quantitative measure of its phase distribution can be extracted. The possibility of capturing simultaneously holograms of three-dimensional specimens, leading to three-dimensional reconstructions with absorption contrast, reflectance contrast, fluorescence contrast, as was previously demonstrated, and quantitative phase contrast, as shown here for the first time, opens up new avenues for multimodal imaging in biological studies.
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    Scanning holographic microscopy with resolution exceeding the Rayleigh limit of the objective by superposition of off-axis holograms
    Indebetouw, Guy J.; Tada, Yoshitaka; Rosen, Joseph; Brooker, Gary (Optical Society of America, 2007-02)
    We present what we believe to be a new application of scanning holographic microscopy to superresolution. Spatial resolution exceeding the Rayleigh limit of the objective is obtained by digital coherent addition of the reconstructions of several off-axis Fresnel holograms. Superresolution by holographic superposition and synthetic aperture has a long history, which is briefly reviewed. The method is demonstrated experimentally by combining three off-axis holograms of fluorescent beads showing a transverse resolution gain of nearly a factor of 2.