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Fresnel zone

About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.


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Patent
10 Dec 2001
TL;DR: In this paper, a maskless stereo lithography method and apparatus for forming a 3D object from a plurality of adhered laminae by exposing successive layers of a photo-curable material to a micro-focused energy beam generated by an array of Fresnel zone plates is presented.
Abstract: A maskless stereo lithography method and apparatus for forming a three-dimensional object from a plurality of adhered laminae by exposing successive layers of a photo-curable material to a micro-focused energy beam generated by an array of Fresnel zone plates. The method includes the steps of (A) providing a controllable array of Fresnel zone plates; (B) forming a layer of material adjacent to any last formed layer of material in preparation for forming a subsequent lamina of the object; (C) exposing the material to the micro-focused energy beam to form the subsequent lamina of the object; and (D) repeating the steps of forming and exposing a plurality of times in order to form the object from a plurality of adhered laminae, wherein the array of Fresnel zone plates are employed to focus parallel beamlets of energy beam from a source so that the beamlets converge to an array of focal points at predetermined positions of a lamina in accordance with a computer-aided design file of the object.

39 citations

Journal ArticleDOI
TL;DR: The reconstructed focal spots demonstrate good agreement with the theoretically expected wavefields and diffraction-limited focusing.
Abstract: We have characterized the x-ray phase vortices generated at the focal spot of various spiral Fresnel zone plates with an outermost zone width of Δr=50 nm. The complex-valued wavefields of phase vortices as small as 50 nm in size (FWHM) and several topological charges were reconstructed using ptychographic coherent diffractive imaging. The reconstructed focal spots demonstrate good agreement with the theoretically expected wavefields and diffraction-limited focusing.

39 citations

Patent
05 Nov 2002
TL;DR: In this article, a Fresnel zone plate and a refractive lens are combined to solve the high chromatic aberration problem of zone plates, allowing the use of short wavelength radiation in the 1-15 nm spectral range.
Abstract: A lithography apparatus having achromatic Fresnel objective (AFO) that combines a Fresnel zone plate and a refractive Fresnel lens. The zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plate. This compound lens effectively solves the high chromatic aberration problem of zone plates. The lithography apparatus allows the use of short wavelength radiation in the 1-15 nm spectral range to print high resolution features as small as 20 nm.

39 citations

Patent
09 Mar 2000
TL;DR: In this paper, a model seismic image of a subsurface seismic reflector is constructed, wherein a set of source and receiver pairs are located, and a sub-surface velocity function is determined.
Abstract: A model seismic image of a subsurface seismic reflector is constructed, wherein a set of source and receiver pairs is located, and a subsurface velocity function is determined. Specular reflection points are determined on the subsurface seismic reflector for each of the source and receiver pairs. A Fresnel zone is determined on the subsurface seismic reflector for each of the specular reflection points, using the subsurface velocity function. One or more seismic wavelets are selected and a set of image points is defined containing the subsurface seismic reflector. A synthetic seismic amplitude is determined for each of the image points by summing the Fresnel zone synthetic seismic amplitude for all of the Fresnel zones that contain the image point, using the seismic wavelets. The model seismic image of the subsurface seismic reflector is constructed, using the synthetic seismic amplitudes at the image points.

38 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202326
202249
202137
202052
201965
201878