Topic
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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21 Jun 2015
TL;DR: In this paper, the authors have demonstrated binary Fresnel zone plates fabricated from silicon nanowires embedded in a PDMS matrix, which can potentially benefit from an increased field of view for applications such as microscopy and surveillance.
Abstract: This paper describes microlens arrays implemented on a flexible substrate For the first time, we have demonstrated binary Fresnel zone plates fabricated from silicon nanowires embedded in a PDMS matrix Lens arrays on flexible substrates can potentially benefit from an increased field of view, which is important for applications such as microscopy and surveillance Lens arrays have wide applications in 3D displays, LCD projectors, optical switches and tunable lasers We report our design, fabrication and imaging demonstration for silicon based microlens arrays
5 citations
TL;DR: The design theory of an apodized diffractive optical element comprised of open-ring zones and pinholes is proposed and developed, which has a 50.19% higher energy efficiency, and the minimum pinhole size is enlarged by 30.77%.
Abstract: In this paper, we investigate the relationship between open-ring zones of the Fresnel zone plate and the pinhole rings of photon sieves (PSs). Numerical simulations show that the normalized diffraction fields near the focal point of an individual pinhole ring and the circular open-ring zone are the same. It is confirmed that the maximum diffraction efficiency of an open-ring zone is higher than that of the traditional pinhole ring. Meanwhile, pinhole rings have more flexibility for apodization filtering. Based on these key findings, we propose the design theory of an apodized diffractive optical element comprised of open-ring zones and pinholes. To validate the theory, we developed a design example. Compared with traditional apodized PSs, the new apodized diffractive element has a 50.19% higher energy efficiency, and the minimum pinhole size is enlarged by 30.77%.
5 citations
5 citations
Patent•
29 Sep 2010TL;DR: In this article, a Fresnel optical element has a plurality of slopes that refract or reflect light, and the variation of the slope angle between adjacent slopes is constant, where slopes are assumed to be uniform.
Abstract: A Fresnel optical element has a plurality of slopes that refract or reflect light, and the variation of the slope angle between adjacent slopes is constant.
5 citations
03 Nov 2020
TL;DR: An interactive tool that allows users to position antennas in different locations over a 3D model of the world and the ability to test clearance in real-time, to support interactive network planning is developed.
Abstract: The growing demand for high-speed networks is increasing the use of high-frequency electromagnetic waves in wireless networks, including in microwave backhaul links and 5G. The relative higher frequency provides a high bandwidth, but it is very sensitive to obstructions and interference. Hence, when positioning a transmitter-receiver pair, the line-of-sight between them should be free of obstacles. Furthermore, the Fresnel zone around the line-of-sight should be clear of obstructions, to guarantee effective transmission. When deploying microwave backhaul links or a cellular network there is a need to select the locations of the antennas accordingly. To help network planners, we developed an interactive tool that allows users to position antennas in different locations over a 3D model of the world. Users can interactively change antenna locations and other parameters, to examine clearance of Fresnel zones. In this paper we illustrate the interactive tool and the ability to test clearance in real-time, to support interactive network planning.
5 citations