Results 201 to 210 of about 99,715 (244)
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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 reflector incorporating rings
IEEE Microwave and Guided Wave Letters, 1993A novel high-efficiency Fresnel zone plate reflector antenna is presented. The reflector consists of an inhomogeneous array of circular conducting rings printed on a grounded substrate. By adjusting the geometrical parameters of the rings and the distances between them, the reflector provides a space-varying phase correction required for focusing an ...
Y.J. Guo, S.K. Barton
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Fresnel zone plate fabricated using a polyvinyl chloride gel
Optical Engineering: The Journal of SPIE, 2018. Based on creep-induced deformation of a polyvinyl chloride (PVC) gel in an electric field, a Fresnel zone plate (FZP) is fabricated. The employed electrode is constructed with a series of concentric zones, and the soft PVC gel coated on the electrode ...
Pingping Huang, Zuowei Zhou, H. Ren
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Optics and lasers in engineering, 2018
A method of obtaining precision transmission wavefront of large convex lens interferometrically using binary Fresnel zone plate (FZP) was presented. We present the results from a set of experiments that demonstrate the accuracy, flexibility, and the ...
Xiaohong Wei +7 more
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A method of obtaining precision transmission wavefront of large convex lens interferometrically using binary Fresnel zone plate (FZP) was presented. We present the results from a set of experiments that demonstrate the accuracy, flexibility, and the ...
Xiaohong Wei +7 more
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Single zone Fresnel dielectric plate antenna
2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2019It is shown that simple dielectric disk with proper chosen refractive index, radius and thickness operate as lens and can increase for more than 10 dB directivity of the antenna couple detectors placed at the focal plane.
A. Hakhoumian, A. Sargsyan
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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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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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Comprehensive focusing analysis of various Fresnel zone plates
Journal of the Optical Society of America A, 2004A series-form expression for the individual diffracted field of a general annular ring is derived from the Rayleigh-Sommerfeld diffraction integral. It can be used for the accurate and fast simulation of any diffractive focusing element composed of concentric transparent rings.
Qing, Cao, Jürgen, Jahns
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Fresnel Zone Plate array fabricated by maskless lithography
2015 30th Symposium on Microelectronics Technology and Devices (SBMicro), 2015This work reports the fabrication of Fresnel Zone Plates (FZP) by employing a maskless lithography tool based on direct laser writing. The target application areas in this work are to use a micro lens array (MLA) in a wavefront sensor, for optical aberrations quantification in human eye diagnostics or adaptive optical system. This last one is essential
Barea, Luis A. +6 more
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Fresnel Zone Plate Imaging of Gamma Rays; Theory
Applied Optics, 1973The use of a Fresnel zone plate as a coded aperture for imaging incoherent radiation such as gamma rays has been previously reported. The coded image is in many respects similar to a hologram and can be decoded or reconstructed with a coherent optical system.
H H, Barrett, F A, Horrigan
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