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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TL;DR: Owing to the superior physical properties of the material, diamond CRLs could become indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings.
Abstract: We report the fabrication and performance evaluation of single crystal diamond refractive x-ray lenses with a paraboloid of rotation form factor for focusing x-rays in two dimensions simultaneously. The lenses were manufactured using a femtosecond laser micromachining process and tested using x-ray synchrotron radiation. Such lenses were stacked together to form a standard compound refractive lens (CRL). Due to the superior physical properties of the material, diamond CRLs are enabling and indispensable wavefront-preserving primary focusing optics for x-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright x-ray sources for secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.
22 citations
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3M1
TL;DR: In this paper, a retroreflective material including a medium containing a plurality of diffraction elements comprising light interference fringe patterns is formed by pressing a first medium having on a surface thereof a multiplicity of light interference fringes defining an array of phase modulated fresnel zone plates onto a surface of a copy medium having a thickness equal to a given focal length associated with the fresnel zones plates and a reflective material is coated on the opposite surface of the copy medium.
Abstract: Retroreflective material including a medium containing a plurality of diffraction elements comprising light interference fringe patterns is formed by pressing a first medium having on a surface thereof a plurality of light interference fringe patterns defining an array of phase modulated fresnel zone plates onto a surface of a copy medium having a thickness equal to a given focal length associated with the fresnel zone plates and a reflective material is coated on the opposite surface of the copy medium. In making other embodiments a plurality of fringe patterns is recorded throughout the volume of a photosensitive medium.
21 citations
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TL;DR: Numerical assessment of the suggested structure shows excellent coupling efficiency (up to 59%) of the 10 mum free-space Gaussian beam to the 0.36 mum Si waveguide within a working distance of a few mum.
Abstract: We propose a novel metal slit array Fresnel lens for wavelength-scale optical coupling into a nanophotonic waveguide. Using the plasmonic waveguide structure in Fresnel lens form, a much wider beam acceptance angle and wavelength-scale working distance of the lens was realized compared to a conventional dielectric Fresnel lens. By applying the plasmon waveguide dispersion relation to a phased antenna array model, we also develop and analyze design rules and parameters for the suggested metal slit Fresnel lens. Numerical assessment of the suggested structure shows excellent coupling efficiency (up to 59%) of the 10 mum free-space Gaussian beam to the 0.36 mum Si waveguide within a working distance of a few mum.
21 citations
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TL;DR: The phase-retrieval method from Fresnel zone intensity data obtained by modulation of the object with a known Gaussian function and with its shifted functions along the horizontal and the vertical directions in rectangular coordinates is considered.
Abstract: The reconstruction of a complex-valued object from intensity measurements in the Fresnel zone region is considered. The reconstruction is based on the phase-retrieval method from Fresnel zone intensity data obtained by modulation of the object with a known Gaussian function and with its shifted functions along the horizontal and the vertical directions in rectangular coordinates. Two types of reconstruction system are presented. In the two systems a Gaussian amplitude filter and a Gaussian illuminating beam are used as the known Gaussian functions. Computer-simulated examples in two dimensions illustrate the performance of the reconstruction in these systems.
21 citations
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TL;DR: In this paper, the authors review the form of the classical radar equation used for incoherent backscatter measurements and relate this form with range dependent gain to experimentally accessible far-field beam pattern measurements.
21 citations