Results 171 to 180 of about 1,347 (193)
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Solid immersion Fresnel zone plate
Digital Holography & 3-D Imaging Meeting, 2015A solid immersion Fresnel zone plate (SIFZP) is designed and its near-field imaging characteristics are analyzed using the vector angular spectrum method. Results show SIFZP can generate a high intensity and subwavelength focus.
Yaoju Zhang +3 more
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Fresnel zone plates for two wavelengths
SPIE Proceedings, 1995This paper proposes two systems of Fresnel Zone Plates which could focus two parallel monochromatic and coherent beams (with different wavelengths), eliminating the wellknown chromatical aberrations of the classical construction.
Eugene O. Curatu +2 more
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Properties and Fabrication of Micro Fresnel Zone Plates
Applied Optics, 1973Arrays of ~2-mm diam, f/9, diffraction-limited Fresnel zone plates are made and measured. Amplitude zone plates are fabricated by conventional photolithographic techniques, while a specially developed evaporation/etching technique is used for phase zone plates.
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Aberrations of curved zone plates and Fresnel lenses
Applied Optics, 1977The generalization of zone plates and Fresnel lenses from the usual flat surfaces to curved surfaces is discussed. It is shown that, although Abbe's sine law applies to zone plates but not to Fresnel lenses, both can yield single-element aplanats if formed on a curved surface. Third-order aberration formulas are given.
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Solution to the Fresnel Zone Plate Problem
American Journal of Physics, 1969The diffraction problem for the Fresnel half-period zone plate is solved. The zone plate behaves as a lens with marked chromatism which can be taken advantage of for use in a spectrometer. The multiplicity of foci associated with the zone plate are examined in detail, and it is shown that the spectral range that can be focused without overlap is 3λmin ...
H. Malcolm Childers, David E. Stone
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Offset Fresnel zone plate antennas
International Journal of Satellite Communications, 1994AbstractThe theory of offset Fresnel zone plate antennas is presented. Explicit formulae for the design of the zone boundaries for the offset Fresnel zone plate are given. Theorectical equations and numerical results for the far‐field analysis are presented.
Y. J. Guo, S. K. Barton
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Fresnel Zone-Plate Diffraction Patterns
Journal of the Optical Society of America, 1969The diffraction patterns of the central aperture and the first 10 rings of the classical Fresnel zone plate are calculated in the principal focal plane for off-axis distances as large as the radius of the 10th ring. The zone-plate pattern is found by summation; near the axis it is compared with closed-form approximations.
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Fresnel zone plate: Anomalous foci
American Journal of Physics, 1976It is found that, when a zone plate is examined in practice, foci exist where there should be none. An approach is developed which reveals that the zone plate is a circular diffraction grating, which in turn explains how a hologram works in a very direct manner.
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[Thyroid scintigraphy with Fresnel zone plates].
Nuklearmedizin. Nuclear medicine, 1985Coded apertures supply a decoupling of resolution and sensitivity in scintigraphic imaging. The reconstructed images are focussed on different planes. The approach presented replaces the conventional collimator by three Fresnel zone plates in order to simulate a complex projection.
J, Meinke +2 more
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