The European Physical Journal C, Volume 78; doi:10.1140/epjc/s10052-018-6465-x
Abstract: In the present work, we generalize our previous work (Heydarzade and Darabi in arXiv:1710.04485, 2018 on the surrounded Vaidya solution by cosmological fields to the case of Bonnor–Vaidya charged solution. In this regard, we construct a solution for the classical description of the evaporating-accreting charged Bonnor–Vaidya black holes in the generic dynamical backgrounds. We address some interesting features of these solutions and classify them according to their behaviors under imposing the positive energy condition. Also, we analyze the timelike geodesics associated with the obtained solutions and show that some new correction terms arise in comparison to the case of standard Schwarzschild black hole. Then, we explore all these features for each of the cosmological backgrounds of dust, radiation, quintessence and cosmological constant-like fields in more detail.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012115
Abstract: Ab initio simulations of optical band gaps of cesium lead halide perovskites CsP b(I 1– xClx)3 and CsP b(I 1– xBrx)3 are performed at the level of general gradient approximation of the density functional theory. We use supercell approach for computational modeling of disordered systems, which gives a description of the properties of the structure basing on the average over a set of multiple configurations, namely distributions of different species over a given set of atomic positions. The calculations were performed with the CRYSTAL 14 program package. The dependence of the band gap on the content x are investigated over the whole range 0 ≤ x ≤ 1.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012109
Abstract: A new form of the linear augmented cylindrical wave method is proposed. For the construction of basis functions, the electron potential is taken to be spherically symmetric in atomic regions, constant in the intermediate region and cylindrically symmetric in the vacuum regions. The basis functions of the method, obtained from the solution of the Schrodinger equation in the corresponding domains, are sewn on the boundaries of the MT-spheres and the cylindrical surfaces of the tube, forming everywhere continuous and differentiable functions. In order to approve a method, the band structure of the non-chiral semiconductor and metallic single-wall carbon nanotubes was calculated.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012112
Abstract: The phase distortions arise due to the atmospheric turbulence, the experimental conditions or a low quality of the imaging system. They can seriously limit the resolution of the image. Phase distortions can be spatially dependent, which means that a linear space-invariant transfer function cannot completely correct all phase errors in the field of view. Computer holography can be used to access a complex-valued optical field from an object under coherent illumination after detecting interference of intensity between the object and the reference beams. In this work, we developed approaches to improve image sharpness to measure phase distortions in computer holography using the example of defocus measurement. Image enhancement algorithms use a nonlinear optimization procedure to determine and measure phase distortions to form a reconstructed image at a high resolution. Our work was focused on numerical modelling, developing algorithms and conducting laboratory experiment.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012108
Abstract: The analytic solution of the problem of propagation of eigen modes in planar periodically inhomogeneous optical waveguides based on alternating dielectric and chiral (or with optical activity) layers is examined. The method is based on the solution of the Hill equations for the electric field strengths of modes with circular polarizations. As a result, a dispersion equation for the eigen modes of a planar periodically inhomogeneous chiral-dielectric waveguide was obtained and its numerical solution was performed. As a result of the analysis of numerical results, it is shown that the structure under study can operate in different modes: propagation of modes with right and left circular polarizations, propagation of a mode with only one type of circular polarization and the optical key mode.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012111
Abstract: In this paper the profile of harmonic lens with a variable height of microrelief was calculated. Moreover, structure of harmonic lens with a constant height of microrelief was displayed. Also, the point-spread function (PSF) for different types of the harmonic lens was shown. The point-spread function for selected types of harmonic lenses was calculated. Comparison of the main maximums sizes in area 40x40 microns when falling 3 wavelengths and 11 wavelengths was made. Finally, the point-spread function of three zones lens is shown.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012126
Abstract: In this work, we propose a technique to enhance the confinement of light at 90o sharp bend of a double high mesa slot (DHMS) waveguide based on Silicon on Insulator (SOI). These waveguides deliver high electric field and optical power density in low refractive index Nano-metric slot. The slot is displaced to the inner and outer periphery of the bend and explores the deviation in the relative power. The maximum relative power is attained by shifting the slot towards the outer periphery of the bend. This is only conceivable by choosing the precise slot position where the two evanescent tails of the high index waveguide modes have maximum overlap.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012125
Abstract: Recently, the attention of researchers has been turned to various beams possessing the property of autofocusing, among which are circular beams of Airy, beams of Pierce, hypergeometric and other beams. The sharp autofocusing property inherent in the above beams is very useful in optical manipulation, useful for multiphoton polymerization, is used for nonlinear effects and for polarization transformations. A classic focusing element is a lens that has a quadratic dependence on the radius. The diffractive version of the parabolic lens has radial lines, condensing to the edge of the optical element as a linear chirp. This structure can be obtained by "twirling" the Airy function along the circumference with displacement and scaling. The study of the behavior of various types of self-focusing laser beams in parabolic environments extends the spectrum of optical signals used for telecommunications. In particular, a fractional Fourier transform is used to describe fibers with a parabolic refractive index. In this paper we consider circular Airy beams, which have a radial dependence. Modelling of the passage of these beams through an optical fiber with a parabolic change in the refractive index was performed on the basis of the use of a fractional Fourier transform.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012105
Abstract: The article is a review of analysis of mathematical models of different types of diffractive intraocular lenses. Bi-, three- and multifocal lenses were the subjects of comparison. There are two approximations of work of intraocular lens: geometric optical approximation and the scalar theory of diffraction. The advantages and disadvantages of bi- three- and multifocal lenses are shown from the position of energy effectively, function of transportation of modulation and point spread function.
Journal of Physics: Conference Series, Volume 1096; doi:10.1088/1742-6596/1096/1/012113
Abstract: In this paper, we analyze the existing methods of digital representation of images and fields, based on calculating digital holograms of various objects. We studied discrete Fourier, cosine and Fresnel transform are compared, advantages and disadvantages of each. Cases of the use of each transformationare suggested. We estimated the quality of reconstructed images using objective metrics such as signal-to-noise ratio and root-mean-square error. The computational complexity of the considered discrete transformations is analyzed.