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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
TL;DR: In this paper , a sharp Gaussian with a disk was used to estimate the background of Rayleigh-Taylor spikes and their interpretation in NIF x-ray radiography images, and an alternative design of FZP was discussed to allow the inclusion of a zeroth order blocker to reduce the background.
Abstract: High spatial and temporal resolution x-ray radiography images are required at the National Ignition Facility (NIF) for high-energy density experiments. One technique that is in development to achieve the required resolution uses Fresnel zone plate (FZP) optics to image an object that is backlit by an x-ray source. The multiple FZP diffraction orders do not focus on the same plane, which increases the background and reduces the contrast. Understanding the point spread function of the different diffraction orders will allow the prediction of the expected background using simulations. We find that the two-dimensional point spread function of the FZP can be approximated by the addition of a sharp Gaussian with a disk. This allowed for the estimation of the background in NIF experimental images of Rayleigh-Taylor spikes and their interpretation. An alternative design of FZP is discussed to allow the inclusion of a zeroth order blocker to reduce the background.
Book ChapterDOI
01 Jan 2022
Proceedings ArticleDOI
01 Jul 2016
TL;DR: In this paper, the optical mechanism of forming reconstructed images in a hologram loaded on a DMD is identified by measuring the light fields at different distances from the hologram, which make it possible to identify the process of forming the reconstructed image, astigmatism, restoring the missing pattern of the holograms, the focusing behavior of Fresnel zone pattern, and depth resolution.
Abstract: The optical mechanism of forming reconstructed images in a hologram loaded on a DMD is identified by measuring the light fields at different distances from a hologram. The light field images make possible to identify the process of forming the reconstructed image, astigmatism, restoring the missing pattern of the hologram, the focusing behavior of Fresnel zone pattern, and depth resolution.
Proceedings ArticleDOI
21 May 2015
TL;DR: This paper shows that in every propagation environment, there is a free space propagation medium, due to the existence of Fresnel Zones, which gives rise to Fresnel zone break point do, and develops a hierarchical cellular structure for the next generation green cellular network comprising Macrocell, Microcell, Picocell and Femtocell.
Abstract: This paper shows that in every propagation environment, there is a free space propagation medium, due to the existence of Fresnel Zones. This gives rise to Fresnel zone break point d o , where d o is the distance between the transmitter and the receiver. Radio frequency propagation within d o is similar to free space propagation. This enables us to design low power small cells to conserve energy, thereby reducing RF & CO2 pollution. With this foundation in mind, we will develop a hierarchical cellular structure for the next generation green cellular network comprising Macrocell, Microcell, Picocell and Femtocell.
Proceedings ArticleDOI
15 May 2011
TL;DR: In this paper, an unknown sample, placed between the transmit and the received antenna, separated by a distance less than the Freznel Zone break point, absorbs electromagnetic energy at a frequency determined by the atomic weight of the unknown sample.
Abstract: This paper presents a method of detecting trace elements in food, beverages and biological samples in real-time. The instrument is based on Electron Spin Resonance and Fresnel Zone break point. It is shown that an unknown sample, placed between the transmit and the received antenna, separated by a distance less than the Freznel Zone break point, absorbs electromagnetic energy at a frequency determined by the atomic weight of the unknown sample. The Freznel Zone break point is used to position the antennas in order to avoid multipath signals. A prototype instrument along with experimental data is presented to illustrate the concept.

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