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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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Journal ArticleDOI
Yahya Baykal1
TL;DR: In this article, the average intensity and power-transmittance in turbulence were formulated for a source with arbitrary degree of coherence (both spatial and temporal) and the average transmittance was found to attain its minimum value when the source is on the order of the Fresnel zone, irrespective of the degree of coherentness of the source.

34 citations

Journal ArticleDOI
TL;DR: In this paper, the surface function is derived from the contours of constant distance from the source which can be drawn in the surface; these are the appropriate analogues of Fresnel zone boundaries.
Abstract: Kirchhoff diffraction theory is set up for the echo received back at the source when a spherical outgoing pulse of radiation is reflected from a rough surface. The formulation derived here permits a clear separation between those features of the echo that depend only on the form of the incident pulse, and those involving only the properties of the surface. The surface function depends on the contours of constant distance from the source which can be drawn in the surface; these are the appropriate analogues of Fresnel zone boundaries. Geometrical optics gives the singularities and discontinuities of the surface function. The problem of determining the surface function from echo data which are incomplete in the sense that they do not contain all radiation frequencies is discussed. For the special case of one dimensional roughness, the problem of how far the surface function can be deconvoluted to obtain the shape of the surface is considered.

34 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a randomly multiplexed bifocal binary diffractive Fresnel zone lenses fabricated using electron beam lithography for super-resolution 3D imaging.
Abstract: Fresnel incoherent correlation holography (FINCH) is a self-interference based super-resolution three-dimensional imaging technique. FINCH in inline configuration requires an active phase modulator to record at least three phase-shifted camera shots to reconstruct objects without twin image and bias terms. In this study, FINCH is realized using a randomly multiplexed bifocal binary diffractive Fresnel zone lenses fabricated using electron beam lithography. The object space is calibrated by axially scanning a point object along the optical axis and recording the corresponding point spread holograms (PSHs). An object is mounted within the calibrated object space, and the object hologram was recorded under identical experimental conditions used for recording the PSHs. The image of the object at different depths was reconstructed by a cross-correlation between the object hologram and the PSHs. Application potential including bio-medical optics is discussed.

34 citations

Journal ArticleDOI
TL;DR: A circular multilayer zone plate (MZP) was fabricated and its focusing performance was evaluated using 20-keV x-rays, suggesting that the MZP has the potential to realize the diffraction-limited resolving power.
Abstract: A circular multilayer zone plate (MZP) was fabricated and its focusing performance was evaluated using 20-keV x-rays. MoSi(2) and Si layers were alternately deposited by DC magnetron sputtering on a wire core; all the interfaces satisfied the Fresnel zone condition. The measured line spread function was converted to a point spread function by tomographic reconstruction. The results suggest that the MZP has the potential to realize the diffraction-limited resolving power, which is calculated to be 35 nm using the diffraction integral. Furthermore, scanning transmission microscopy using the MZP could resolve a 50-nm line-and-space pattern.

34 citations

Journal ArticleDOI
TL;DR: In this paper, a transverse grating structure on the alignment mark on the wafer wafer is used to eliminate unwanted diffraction orders and eliminate the need for a transversal grating.
Abstract: The alignment system described in this paper is applicable to all proximity mode replication systems. The inherent high accuracy of the method makes it particularly attractive for submicron lithography applications requiring positioning accuracy of better than 0.1 μm. The basic alignment mark on the mask is a one dimensional Fresnel zone whose primary focal length is equal to the proximity gap spacing. Helium–Neon laser illumination is used. Elimination of unwanted diffraction orders is achieved by incorporating a transverse grating structure on the alignment mark on the wafer. The alignment signal sensitivity to gap variation is such that it allows very precise setting of the gap spacing in an unambiguous fashion. Three pairs of such alignment marks are necessary to provide x–y–ϑ registration as well as gap spacing and parallelism settings. A key feature of the alignment system is the time varying incidence angle of the laser beam upon each Fresnel zone mark, which results in a small amplitude scanning of the wafer surface and allows continuous registration throughout the entire exposure duration. A description of the alignment system designed for a submicron x‐ray lithography system is given, together with some preliminary results.

34 citations


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