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Purpose: This paper aims to examine the uniform diffracted fields from a perfectly magnetic conductive (PMC) surface with the extended theory of boundary diffraction wave (BDW) approach. Design/methodology/approach: Miyamoto and Wolf's symbolic expression of the vector potential was used in the extended theory of BDW integral. This vector potential is applied to the problem, and the nonuniform field expression found was made uniform. Here, the expression is made uniform, using the detour parameter with the help of the asymptotic correlation of the Fresnel function. The BDW theory for the PMC surface extended the diffracted fields, and the uniform diffracted fields were calculated. Findings: The field expressions obtained were interpreted with the graphs numerically for different aperture radii and observation distances. It has been shown that the BDW is continuous behind the diffracting aperture. There does not exist any discontinuity at the geometrically light-to-shadow transition boundary, as is required by the theory. Originality/value: The results were graphically compared with diffracted fields for other surfaces. As far as we know, the uniform diffracted fields from the circular aperture on a PMC surface were calculated for the first time with the extended theory of the BDW approach. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a method for restoration of heavily damaged digital off-axis Fresnel holograms based on image inpainting. Being different from existing image inpainting algorithms, we have employed Artificial Bee Colony search technique to increase the computation efficiency of the inpainting process, resulting in a reduction of over one order of magnitude in the computation time. Briefly, an exemplar and search based image inpainting technique is applied to fill in the damaged regions in the hologram, with the most similar fringe patterns in the intact areas obtained from Artificial Bee Colony search algorithm. Experimental results reveal that with our proposed method, the pictorial information in heavily damaged holograms can be recovered with good fidelity, as compared with those obtained with the original intact holograms. This is the first time that image inpainting technique is applied on hologram restoration. [ABSTRACT FROM AUTHOR]

The manipulation of low-energy beams of neutral atoms and molecules via their de Broglie wavelength is a branch of atom optics often referred to as de Broglie matter wave optics. The application areas include fundamental quantum mechanics, atom interferometry, and the development of new microscopy instrumentation. The focusing of de Broglie matter waves with a Fresnel zone plate was used to demonstrate the first neutral helium microscopy imaging. The ultimate resolution of such a microscope is limited by the width of the outermost zone. Because a Fresnel zone plate for atoms cannot be fabricated on a substrate (the low-energy atom beams would not be able to penetrate the substrate material), this gives a fabrication determined limit for the first-order focus of around 30-50 nm. Therefore, it is important to search for alternative optical elements that enable higher resolution. Photon sieves consist of a large number of pinholes, arranged suitably relative to the Fresnel zones. The great advantages are that the width of the pinholes can be larger than the respective Fresnel zones and a free-standing pinhole is much easier to fabricate than a free-standing zone. Thus, with a photon-sieve structure applied for de Broglie matter wave manipulation, the fabrication limit for focusing is reduced to potentially around 3-5 nm. Here we present a realization of such an "atom sieve," which we fabricated out of a silicon nitride (SiN) membrane, using electron-beam lithography and reactive ion etching. Our atom sieve is 178 μm in diameter and has 31?991 holes. The diameter of the holes varies from 1840 to 150 nm. Using a beam of neutral, ground-state helium atoms with an average wavelength of 0.055 nm, we demonstrate helium atom focusing down to a spot size of less than 4 μm. The focus size is limited by the intrinsic velocity spread of the helium beam. [ABSTRACT FROM AUTHOR]

Abstract: Some escape and dynamical properties for a beam of light inside a corrugated waveguide are discussed by using Fresnel reflectance. The system is described by a mapping and is controlled by a parameter defining a transition from integrability ( ) to non integrability ( ). The phase space is mixed containing periodic islands, chaotic seas and invariant tori. The histogram of escaping orbits is shown to be scaling invariant with respect to . The waveguide is immersed in a region with different refractive index. Different optical materials are used to overcame the results. [Copyright &y& Elsevier]

We present a solution to the phase problem in near-field x-ray (propagation) imaging. The three-dimensional complex-valued index of refraction is reconstructed from a set of projections recorded in the near-field (Fresnel) setting at a single detector distance. The solution is found by an iterative algorithm based only on the measured data and the three-dimensional tomographic (Helgason-Ludwig) consistency constraint without the need for further a priori knowledge or other restrictive assumptions. [ABSTRACT FROM AUTHOR]

Optical switches, OTDR devices and POF based fiber strain sensors have been connected in order to investigate the sensitivity to strain and quality of the signal regarding the limiting influence of the switches additional Fresnel reflexions. [ABSTRACT FROM AUTHOR]