Fresnel zone

About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.

High Resolution Imaging of Magnetic Domains with Magnetic Soft X-ray Microscopy

Abstract: X-ray magnetic circular dichroism (X-MCD), i.e. the dependence of the absorption coefficient of circularly polarized X-rays on the projection of the magnetization in a ferromagnetic system onto the photon propagation direction, yields e. g. at L2,3 edges in transition metals large values up to 50%. In combination with a soft x-ray microscope where Fresnel zone plates as optical elements provide a lateral resolution down at 25nm, X-MCD can be used to image magnetic microstructures. This photon based technique allows for recording images in varying external magnetic fields, it exhibits inherent chemical specificity, a high sensitivity due to the large contrast and allows to distinguish between in-plane and out-of plane contributions. In this report the basic features of this novel technique will be outlined and results obtained with the XM-1 microscope at the ALS (Berkeley/CA) with thermomagnetically written bits in magneto-optical storage systems demonstrate the applicability of this new experimental technique to technological relevant issues.

Communication area inspecting device

Abstract: PROBLEM TO BE SOLVED: To inspect the communication area between opposite two stations for simply performing radio communication on a desk. SOLUTION: When an inspection condition input section 11 inputs inspection conditions including the position information of first and second stations to be communicated, a Fresnel zone calculating section 12 calculates the Fresnel zone between the first and second stations, based on the inputted inspection conditions; a site information searching section 13 for searching a site directly below the calculated Fresnel zone; a building information searching section 14 searches the building information of a building in the searched site; and an obstruction determination section 15 determines the presence or absence of a building that may be within the Fresnel zone, based on the searched building information. A result output section 16 outputs a result in which a communication trouble occurs, and a result in which no communication troubles occur, when there are buildings that may be within the Fresnel zone and when there are no buildings within the Fresnel zone, respectively. COPYRIGHT: (C)2005,JPO&NCIPI

Diffraction by a half-plane: a generalization of the Fresnel diffraction theory

Abstract: A generalization of the Fresnel approximation in diffraction theory is proposed. The phase term in the diffraction integral is approximated by a parabolic variation, not by a binomial expansion but rather by matching up at the critical points for asymptotic evaluation of the integral. The method provides a correction to the optical coordinates of the Fresnel diffraction theory that extends its region of validity. It is applied to diffraction of an inclined plane wave by a half-plane.

Comments on “Focusing Characteristics of Curvilinear Half-Open Fresnel Zone Plate Lenses: Plane Wave Illumination”

Abstract: For original paper by Hristov et al., see IEEE Trans. Antennas Propag., vol.53, p.1912-19 (2005 June)