Optics express
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We present a parallel implementation of the Fresnel transform suitable for reconstructing large digital holograms. Our method has a small memory footprint and utilizes the spare resources of a distributed set of desktop PCs connected by a network. We show how we parallelize the Fresnel transform and discuss how it is constrained by computer and communication resources. Finally, we demonstrate how a 4.3 gigapixel digital hologram can be reconstructed and how the efficiency of the method changes for different memory and processor configurations.
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Sidestream Dark Field (SDF) imaging, a stroboscopic LED ring-based imaging modality, is introduced for clinical observation of the microcirculation. SDF imaging is validated by comparison to Orthogonal Polarization Spectral imaging. Nailfold capillary diameters and red blood cell velocities were measured using both techniques and equal quantitative results were obtained. ⋯ Venular contrast, sharpness, and quality were shown to be comparable for OPS and SDF imaging. However, capillary contrast and quality were shown to be significantly higher using SDF imaging. Venular granularity, in addition, was more clearly observable using SDF imaging.
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We appreciate the authors' comments in their reply: "On the identification of chromosomes with Raman spectroscopy: a critical comment" [Opt. Express 15, 5997 (2007)]. Their main concern with our paper is asking if the collected spectra have shown the identification or differentiation between three human chromosomes. We think this comment is flawed because the authors misunderstood the main points of the original paper and interpreted the presented spectra data (Fig. 3 and Table 1) incorrectly.
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A new method for confining and guiding two-dimensional (2D) optical waves is proposed using low-refractive-index materials as cores of metal-gap waveguides. A proper choice of the refractive index of claddings prohibits 2D optical waves from propagating inside the claddings, resulting in strong confinement of waves inside the low-refractive-index cores. We numerically demonstrate that this new method for guiding 2D optical waves can achieve stronger confinement than the conventional one using high-refractive-index cores. This strong confinement leads to efficient guiding of 2D optical waves not only at straight path, but also at sharp 90 degrees bends with negligible radiation losses.
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Titles have been indexed alphabetically under the first author of the manuscript. Other authors are listed with a reference back to the first author.