Results 161 to 170 of about 1,347 (193)
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SPIE Proceedings, 1985
A description is given of the use of the Fresnel zone plate as a focusing or a frequency-filtering device at millimeter wavelengths. Sample design data are given, as well as references to prior results. A newer type of zone plate is discussed which employs two dielectrics of equal thickness to produce a flat zone plate.
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A description is given of the use of the Fresnel zone plate as a focusing or a frequency-filtering device at millimeter wavelengths. Sample design data are given, as well as references to prior results. A newer type of zone plate is discussed which employs two dielectrics of equal thickness to produce a flat zone plate.
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Array illumination of a Fresnel–Dammann zone plate
Applied Optics, 2016The traditional Dammann grating is a phase-only modulation, and its theoretical foundation is based on far-field diffraction. Here we extend the traditional Fresnel zone plate (FZP) into a Fresnel-Dammann zone plate (FDZP), which is, in essence, considered as a FZP with Dammann modulation.
Yayao, Ma +5 more
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Variations on the Fresnel Zone Plate
Journal of the Optical Society of America, 1966The effects of contrast in the Fresnel zone plate on the amplitude in the focal point due to a normally incident plane wave are obtained by direct evaluation of the Fresnel–Kirchhoff diffraction integral. The change in focal-point amplitude due to smoothing the ordinary, discontinuous, “square-wave” transmission function into a continuous, “sine-wave ...
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Fresnel Zone Plate and Fresnel Phase Plate Patterns for Acoustic Transducers
1984An ultrasonic transducer with an electrode pattern in the shape of a Fresnel zone plate (FZP) is useful in acoustic imaging. However a major problem in focusing with an FZP is that the final image will have a large zero-order component and this will restrict the dynamic range of the system.
M. Mortezaie, G. Wade
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Imaging and focusing of atoms by a fresnel zone plate
Physical Review Letters, 1991Focusing of and imaging with atoms by means of a spherical Fresnel zone plate has been observed for the first time. An intense beam of metastable helium atoms with atomic de Broglie wavelength ${\ensuremath{\lambda}}_{\mathrm{dB}}$=0.5--2.5 \AA{} is passed through either a single or a double slip with dimensions in the 10-\ensuremath{\mu}m range.
, Carnal +4 more
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Quantum Noise in Fresnel Zone Plate Imaging
Applied Optics, 1974A Fresnel zone plate, used as a coded aperture, offers a great advantage in geometric collection efficiency over a conventional pinhole or collimator. We present a detailed analysis of the signal-to-noise ratio (SNR) of a quantum-limited zone plate camera.
H H, Barrett, G D, Demeester
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An improved zoning rule of the Fresnel zone plate
Microwave and Optical Technology Letters, 1999In the traditional zoning rule of the Fresnel zone plate (FZP), the distance from two edges of each zone to a common focus is progressively increased with a half-wavelength step. In this paper, a more reasonable zoning rule is proposed to further increase the antenna gain by about 1 dB. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 69–73,
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Focalization of Fresnel-Cantor zone plates
SPIE Proceedings, 2003We extend the results obtained for different cases of the product superposition between periodic functions to the case of circular symmetry. The characteristics of focalization for such case is studied. We name Fresnel-Cantor zone plate to the structures obtained.
Diana E. Calva Mendez, Mario M. Lehman
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The elliptical Fresnel-zone plate antenna
Ninth International Conference on Antennas and Propagation (ICAP), 1995The growing number of direct broadcast satellites (DBS) asks for simple, low-cost home receiving systems. The use of the Fresnel-zone plate antenna (FZPA), which is related to the optical lens, is also promising for this application. The aperture of the FZPA is plane and its structure is determined by the well-known Fresnel ellipsoids.
van Houten, J.M., Herben, M.H.A.J.
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Acoustic Fresnel zone plate transducers
Applied Physics Letters, 1974Experimental focal plane intensity distributions are presented for a 10-zone acoustic zone plate operating at approximately 10 MHz. The results are related to the spatial frequency response of the transducer. Some initial imaging experiments with this transducer are described along with preliminary results for an acoustic phase plate.
S. A. Farnow, B. A. Auld
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