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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04 Mar 2022
TL;DR: In this article , an active flexible three-dimensional tunable spiral plate (3DSP) was proposed to enable tunability in both wavelength and depth of focus by actively modifying the lateral and vertical planes.
Abstract: Diffractive optical elements (DOEs) have a number of advantages over refractive or reflective optical elements, including improved dispersion, wider profile tolerances, and greater design freedom. A critical DOE, the Fresnel zone plate (FZP) is widely used in a variety of optical systems, including nano/micro focusing lenses, X-ray imaging, and beam shaping. Optics research on tunable functional devices has a long history of being an enticing field, having a significant impact on the evolution of optical information technology and photonic integrated circuits. The active-spiral Fresnel zone plate (ASFZP), the nanoscale polymer-dispersed liquid crystals (LC) tunable Fresnel lens, and the tunable spiralized Fresnel zone plate are all examples of tunable zone plates. All previously described tunable zone plates achieve tunability by modifying their properties or shape in two dimensions along the lateral plane. In this study, we demonstrate an active flexible three-dimensional tunable spiral plate (3DSP). Rather than alternating bright and dark zones, these zone plates have a spiral pattern in three dimensions. These zone plates enable tunability in both wavelength and depth of focus by actively modifying the lateral and vertical planes. These zone plates achieve a combination of selective wavelength transmission and predefined depth of focus by activating the 3DSP to predefined settings.
15 Aug 2022
TL;DR: In this paper , the relative standard deviation (RSDF) is used to determine the uniformity of Fresnel fold maps and to identify the optimal positioning of the infill stations.
Abstract: The Fresnel zone determines the horizontal resolution of seismic surveys at various depths, velocities, and frequency contents. Therefore, an optimal seismic survey design can greatly benefit from the Fresnel zone analysis. We propose using the relative standard deviation (RSDF) as a quantitative measure to determine the uniformity of Fresnel fold maps. Minimizing the RSDF values for various infill station scenarios could identify the optimal positioning of the infill stations. We have examined the effectiveness of Fresnel zone binning analysis by decimating and introducing gaps in a real seismic data set.
TL;DR: In this paper, the authors optically assess Fresnel zone plates (FZPs) that are designed to guide cold atoms, and show that they give an average RMS error in the brightest part of the ring of 3% with respect to trap depth.
Abstract: We optically assess Fresnel zone plates (FZPs) that are designed to guide cold atoms. Imaging of various ring patterns produced by the FZPs gives an average RMS error in the brightest part of the ring of 3% with respect to trap depth. This residue is attributed to the imaging system, incident beam shape and FZP manufacturing tolerances. Axial propagation of the potentials is presented experimentally and through numerical simulations, illustrating prospects for atom guiding without requiring light sheets.
TL;DR: The focal properties of a set of two modified zone plates are studied by Fresnel-Kirchhoff diffraction formula, and it can give high spatial resolution and large field intensity for extreme ultraviolet and soft X-ray applications as mentioned in this paper.
Abstract: The focal properties of a set of two modified zone plates are studied by Fresnel-Kirchhoff diffraction formula, and it can give high spatial resolution and large field intensity for extreme ultraviolet and soft X-ray applications.
TL;DR: In this article, the amplitude distortions of a given mode are mainly caused by inhomogeneities located on certain (particular to each mode) regions of the surface of the waveguide.
Abstract: Amplitude variations of modes (excited by a point source in a multimode waveguide) due to scattering by an uneven boundary are calculated in a Born approximation. The boundary is a sine curve with a smoothly varying (in space) amplitude. It is shown that amplitude distortions of a given mode are chiefly caused by inhomogeneities located on certain (particular to each mode) regions of the surface. The concept of Fresnel zones for the modes is introduced to simplify analysis of the corresponding effects.