Lacunar fractal photon sieves
نویسندگان
چکیده
منابع مشابه
Ultra-broadband achromatic imaging with diffractive photon sieves
Diffractive optical elements suffer from large chromatic aberration due to the strong wavelength-dependent nature in diffraction phenomena, and therefore, diffractive elements can work only at a single designed wavelength, which significantly limits the applications of diffractive elements in imaging. Here, we report on a demonstration of a wavefront coded broadband achromatic imaging with diff...
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Spatial shaping of light beams has led to numerous new applications in fields such as imaging, optical communication, and micromanipulation. However, structured radiation is less well explored beyond visible optics, where methods for shaping fields are more limited. Binary amplitude filters are often used in these regimes and one such example is a photon sieve consisting of an arrangement of pi...
متن کاملNonparaxial model for the focusing of high-numerical-aperture photon sieves.
Recently, a paraxially individual far-field model was presented for the focusing and imaging analysis of pinhole photon sieves. By use of a local Taylor expansion of the integrated function of the Rayleigh-Sommerfeld diffraction formula, the small-size property of the individual pinholes, and the linear superposition principle, we extend this model to the nonparaxial case of high-numerical-aper...
متن کاملFractal analysis of retinal vessels suggests that a distinct vasculopathy causes lacunar stroke.
OBJECTIVES Lacunar strokes account for 25% of all ischemic strokes and may represent the cerebral manifestation of a systemic small vessel vasculopathy of unknown etiology. Altered retinal vessel fractal dimensions may act as a surrogate marker for diseased cerebral vessels. We used a cross-sectional study to investigate fractal properties of retinal vessels in lacunar stroke. METHODS We recr...
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with fκ(s) as large as possible (resp. Fκ(s) as small as possible) given that the above inequality holds for all choices of A satisfying (1). Selberg [2] has shown (in a much more general context) that the functions fκ(s), Fκ(s) are continuous, monotone, and computable for s > 1, that they do not change if we replace (1) with (2), and that they tend to 1 exponentially as s goes to infinity. Mor...
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ژورنال
عنوان ژورنال: Optics Communications
سال: 2007
ISSN: 0030-4018
DOI: 10.1016/j.optcom.2007.03.086