منابع مشابه
Gamma Ray Fresnel lenses – why not ?
Fresnel lenses offer the possibility of concentrating the flux of X-rays or gamma-rays flux falling on a geometric area of many square metres onto a focal point which need only be a millimetre or so in diameter (and which may even be very much smaller). They can do so with an efficiency that can approach 100%, and yet they are easily fabricated and have no special alignment requirements. Fresne...
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Phase Fresnel lenses have the same imaging properties as zone plates, but with the possibility of concentrating all of the incident power into the primary focus, increasing the maximum theoretical efficiency from 11% to close to 100%. For X-rays, and in particular for gamma-rays, large, diffraction-limited phase Fresnel lenses can be made relatively easily. The focal length is very long for exa...
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Group velocity control is demonstrated for x-ray photons of 14.4 keV energy via a direct measurement of the temporal delay imposed on spectrally narrow x-ray pulses. Subluminal light propagation is achieved by inducing a steep positive linear dispersion in the optical response of 57Fe Mössbauer nuclei embedded in a thin film planar x-ray cavity. The direct detection of the temporal pulse delay ...
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In this paper, a procedure for analyzing and designing of tunable wideband band-pass and band-stop graphene based filters in the terahertz band is proposed. These planar wideband plasmonic filters are unique in their kind. With this procedure, it is possible to design filters with the desired functional characteristics in the form of the similar quarter-wavelength resonance stubs. The discontin...
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Achromatic combinations of a diffractive phase Fresnel lens and a refractive correcting element have been proposed for x-ray and gamma-ray astronomy and for microlithography, but considerations of absorption often dictate that the refractive component be given a stepped profile, resulting in a double Fresnel lens. The imaging performance of corrected Fresnel lenses, with and without stepping, i...
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ژورنال
عنوان ژورنال: Experimental Astronomy
سال: 2020
ISSN: 0922-6435,1572-9508
DOI: 10.1007/s10686-020-09680-x