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Scattering of a Laguerre-Gaussian beam bycomplicated shaped biological cells

Mei Yu, Yiping Han, zhiwei cui, and Haoyu Sun

Doc ID: 330079 Received 24 Apr 2018; Accepted 18 Jul 2018; Posted 18 Jul 2018  View: PDF

Abstract: In this paper, we generalize the method of moments (MOM) based on the surface integral equation (SIE) method toinvestigate the scattering properties of complicated shaped biological cells illuminated by a Laguerre-Gaussianbeam (LGB). We introduce the Lorentz-gauge vector potential with slowly varying envelope amplitude whichsatisfies the paraxial wave equation to obtain the electric and magnetic field components of the incident beam. TheSIE method is applied to compute the scattering field of arbitrary shaped biological cells, the MLFMA is utilized toefficiently solve the resulting matrix equations, and a home-made FORTRAN program is written. Then we explorethe influence of the beam parameters (radial parameter, azimuthal parameter, waist radius, and beam centerposition of a LGB) on the differential scattering cross section (DSCS) for a red blood cell at great length. Somenumerical results on the DSCS for complicated shaped biological cells, such as a fusiform cell and a bacteriophageanatomy illuminated by a LGB are given, showing powerful capability of our approach. As a rapidly advancing field,the investigation of the scattering properties on complicated shaped biological cells illuminated by a LGB will holda wealth of potential for the study of fundamental properties of light and exciting applications in medical field.

Generalized parabolic nondiffracting beams of two orders

Svetlana Khonina, Andrey Ustinov, and Sabino Chavez-Cerda

Doc ID: 332044 Received 18 May 2018; Accepted 18 Jul 2018; Posted 18 Jul 2018  View: PDF

Abstract: In this paper we consider a generalization of standard nondiffracting parabolic beams. The proposed generalized beams have two orders: a continuous parameter a, as in standard beams, and the new parameter is an integer index m. Physically, the last parameter is equal to the number of rotated repetitions of the structure of the original angular spectrum on the total circle in the frequency space. Theoretical investigation shows that for a=0 the beams are real functions and have a symmetry of order 2m. If |a|>0 the beams will be real functions only for odd values of m. Moreover, in this case the beams have a symmetry of order m, while for even values of m the order of symmetry is 2m. The results of numerical simulation confirm these conclusions. Examples of generalized travelling parabolic waves, which are formed on the basis of generalized static parabolic beams, are also given.

M-Pulse Amplitude Modulation of Flat-Topped Beam for Aeronautical Laser Communications

Hamza Gerçekcioglu

Doc ID: 325271 Received 06 Mar 2018; Accepted 18 Jul 2018; Posted 19 Jul 2018  View: PDF

Abstract: Using Rytov method, bit error rate ( ) performances of M-Pulse Amplitude Modulation (M-PAM) are investigated for the flat-topped beam when such a beam is employed in aeronautical laser communication system operating in vertical paths having weak atmospheric turbulence. By using the on-axis scintillation index and the log-normal distributed intensity, the average bit error rate ( ) is evaluated for M-PAM when . The scintillation indices of collimated flat-topped beams of various flatness orders N are compared against propagation lengths, source sizes, zenith angle for laser communication vertical paths, including uplink and downlink. Also, versus the average signal to noise ratio ( ) is examined for various beam flatness orders. It is shown that as the flatness order increases, the scintillation index decreases. Taking one of best flatness order value N=15 for reducing the scintillations, versus propagation lengths, source sizes, zenith angle and are found for various values of M. When M is increased, is found to deteriorate.

Direct Detection Receiver for Vortex Beam

Judy Kupferman and Shlomi Arnon

Doc ID: 330073 Received 23 Apr 2018; Accepted 18 Jul 2018; Posted 19 Jul 2018  View: PDF

Abstract: We present the theory of a direct detection receiver for vortex beams for optical wireless communication (OWC) system. The proposed receiver has an array of annular detectors, which enables analysis of power distribution of the vortex beam. We give a detailed description, numerical optimization, and different options for its design. One possible application of this receiver could be high security communication systems, another could be intra data center communication. Using a given set of parameters, we find that a seven ring symmetrically spaced detector is comparable to a three ring detector with optimized ring area.

Planewave scattering by an ellipsoid composed of anorthorhombic dielectric–magnetic material

Hamad Alkhoori, Akhlesh Lakhtakia, James Breakall, and Craig Bohren

Doc ID: 334468 Received 05 Jun 2018; Accepted 17 Jul 2018; Posted 17 Jul 2018  View: PDF

Abstract: The extended boundary condition method (EBCM) can be used to study planewave scattering by an ellipsoidcomposed of an orthorhombic dielectric-magnetic material whose relative permittivity dyadic isa scalar multiple of its relative permeability dyadic. The scattered and internal field phasors can be expandedin terms of appropriate vector spherical wavefunctions with unknown expansion coefficients,whereas the incident field phasors can be similarly expanded but with known expansion coefficients. Thescattered-field coefficients are related to the incidence-field coefficients through a matrix, and the scattering,absorption, and extinction efficiencies are calculated thereby in relation to the propagation directionand the polarization state of the incident plane wave, the constitutive-anisotropy parameters, and the nonsphericityparameters of the ellipsoid. The eigenvectors of the real permittivity dyadic are aligned alongthe three semi-axes of the ellipsoid. As the electrical size of the ellipsoid increases, multiple lobes appearin the scattering pattern. The total scattering efficiency can be smaller than the absorption efficiency forsome configurations of the incident plane wave but not necessarily for others. The nonsphericity of theobject has a stronger influence on the total scattering efficiency than on the absorption efficiency. Theforward-scattering efficiency increases monotonically with the electrical size for all configurations of theincident plane wave, and so does the backscattering efficiency for some configurations. For other configurations,the backscattering efficiency has an undulating behavior with increase in electrical size, and ishighly affected by the shape and the constitutive anisotropy of the ellipsoid. Even though the ellipsoid isnot necessarily a body of revolution, it is anisotropic, and it is not impedance matched to free space, thebackscattering efficiency can be minuscule but the forward-scattering efficiency is not. This feature canbe useful for harvesting electromagnetic energy.

Reflection and refraction problems for metasurfacesrelated to Monge-Ampère equations

Cristian Gutierrez and Luca Pallucchini

Doc ID: 330499 Received 02 May 2018; Accepted 16 Jul 2018; Posted 17 Jul 2018  View: PDF

Abstract: A metasurface is a surface, typically a plane, on which a function called phase discontinuity is chosenso that the metasurface produces a desired reflection or refraction job. We derive the equations that thephase discontinuity function must satisfy, these are Monge-Ampère partial differential equations, and weprove existence of solutions.

The Degree of Polarization in the Focal Region of a Lens

Xinying Zhao, Taco Visser, and Govind Agrawal

Doc ID: 335497 Received 18 Jun 2018; Accepted 15 Jul 2018; Posted 16 Jul 2018  View: PDF

Abstract: We examine the three-dimensional distribution of the degree of polarization (DOP) in the focal region of a thin, paraxial lens. Analytic expressions for the case of a focused Gaussian Schell-model beam are derived. These show that the DOP satisfies certain spatial symmetry relations. Furthermore, its value varies strongly in the vicinity of the geometrical focus, and its maximum, which need not occur at the focus, can be significantly higher than that of the incident beam.

Spatio-spectral binary patterns based on multispectral filter arrays for texture classification

Sofiane Mihoubi, Olivier Losson, Benjamin Mathon, and Ludovic Macaire

Doc ID: 330378 Received 01 May 2018; Accepted 12 Jul 2018; Posted 13 Jul 2018  View: PDF

Abstract: To discriminate gray-level texture images, spatial texture descriptors can be extracted using the local binary pattern operator. This operator has been extended to color images at the expense of increased memory and computation requirements. Some authors propose to compute texture descriptors directly from raw images provided through a Bayer color filter array, which both avoids the demosaicing step and reduces the descriptor size. Recently, multispectral snapshot cameras have emerged to sample more than three wavelength bands using a multispectral filter array. Such cameras provide a raw image in which a single spectral channel value is available at each pixel. In this paper we design a local binary pattern operator that jointly extracts the spatial and spectral texture information directly from a raw image. Extensive experiments on a large dataset show that the proposed descriptor has both reduced computation cost and high discriminative power with regard to classical LBP descriptors applied to demosaiced images.

Binocular holographic three-dimensional display using a single spatial light modulator and a grating

Yanfeng Su, Zhijian Cai, Quan Liu, Lingyan Shi, Feng Zhou, and Jianhong Wu

Doc ID: 332451 Received 24 May 2018; Accepted 12 Jul 2018; Posted 13 Jul 2018  View: PDF

Abstract: In this paper, a binocular holographic three-dimensional (3D) display system by combining a single spatial light modulator (SLM) and a grating is proposed and implemented. A synthetic phase-only hologram of the left and right 3D perspective images of an object is calculated by the layer-based Fresnel diffraction method according to the depth information, and uploaded onto the SLM for holographic 3D reconstruction with correct depth cues. The grating is designed and fabricated to guide the reconstructed left and right 3D perspective images to the corresponding eye, respectively. Optical experiments demonstrate that the proposed system can successfully present binocular holographic 3D images with both of the accommodation effect and binocular parallax, which enables the observer free of the accommodation-vergence conflict and visual fatigue problem.

Near Infrared Polarimetric Imaging and ChangesAssociated with Normative Aging

Joel Papay and Ann Elsner

Doc ID: 325821 Received 12 Mar 2018; Accepted 10 Jul 2018; Posted 11 Jul 2018  View: PDF

Abstract: With aging, the human retina undergoes cell death and additional structural changes that can increase scatteredlight. We quantified the effect of normative aging on multiply scattered light returning from the human fundus. Asexpected, there was an increase of multiply scattered light associated with aging, and this is consistent with thehistological changes that occur in the fundus of individuals before developing age-related macular degeneration.This increase in scattered light with aging cannot be attributed to retinal reflectivity, anterior segment scatter, orpupil diameter.

Control of plasmon-polariton vortices on the surface of metal layer

Igor Dzedolik and Vladislav Pereskokov

Doc ID: 330629 Received 03 May 2018; Accepted 09 Jul 2018; Posted 10 Jul 2018  View: PDF

Abstract: Surface plasmon polaritons (SPPs) can be excited at the interface of metal layer and dielectric layer by various methods. If an inhomogeneity of permittivity with a curvilinear boundary is created in the metal layer by the external electric field, the incident SPPs and the reflected ones from this inhomogeneity interfere. A vortex lattice appears when such SPPs interfere, and the lattice configuration can be controlled by varying of the external electric field. Based on controlling of the SPP vortex lattice and reading out of the vortex localization, the plasmon logic gates “AND”, “OR” and “NOT” can be realized. These logic gates are the complete elemental base for logical operations in processors operating at optical frequencies.

Theoretical investigations of infrared optical wave MTF models in anisotropic marine turbulence

Linyan Cui, Wen Fei, and Bindang Xue

Doc ID: 330916 Received 03 May 2018; Accepted 09 Jul 2018; Posted 13 Jul 2018  View: PDF

Abstract: Previously derived marine turbulence modulation transfer function (MTF) adopts classical assumption of isotropic and Kolmogorov turbulence. However, more theoretical researches show that the marine turbulence demonstrates anisotropic non-Kolmogorov properties. In this study, new long exposure plane and spherical waves MTF models under anisotropic non-Kolmogorov marine turbulence will be investigated. Comparative analyses are performed for the new models and the existed ones which have been developed under the isotropic marine turbulence and the anisotropic terrestrial turbulence cases. It turns out that the anisotropic marine turbulence influences less on the electro-optical imaging system than the isotropic marine turbulence. Also, under the same turbulence strength condition, due to the humidity fluctuations of marine atmosphere, the anisotropic marine turbulence will reduce more severely the quality of electro-optical imaging system than the anisotropic terrestrial turbulence. Investigations conducted in this paper are beneficial to understand better the electro-optical imaging mechanism in marine atmospheric turbulence media.

Linear controllers error budget assessment forclassical adaptive optics systems

Rémy JUVENAL, Caroline Kulcsar, Henri-François Raynaud, and Jean-Marc Conan

Doc ID: 337904 Received 05 Jul 2018; Accepted 07 Jul 2018; Posted 11 Jul 2018  View: PDF

Abstract: Understanding limitations of Adaptive Optics (AO) systems is crucial when designing new systems. Inparticular, analyzing the potential of different controllers is of great interest for the upcoming AO systemsof the VLTs and ELTs. This paper thus details a complete error budget assessment formalism, basedon analytic formulas involving the disturbance temporal Power Spectral Density (PSD) and the controllertransfer function, and thus applicable to any linear controller. This formalism is presented here for thespecial case of classical AO systems, but can be extended to any closed or open-loop, single or multiconjugatedAO configuration. Special attention is paid to the “control-dependent” errors, the importanceof which is directly related to the type of control used in the AO system. The proposed method is appliedto a NAOS/VLT-type SCAO system, using disturbance PSD derived from a simulated turbulence trajectoryor estimated from WFS measurements, enabling to construct detailed error budgets for an integratorand different LQG controllers. Application to ELT-sized systems is discussed in the conclusion.

Beam wander of a partially coherent Airy beam inoceanic turbulence

wei wen, Ying Jin, Mingjun Hu, Mi Luo, Yang Luo, Xianwu Mi, Chenjuan Zou, Liwang Zhou, Chengfu Shu, Xixiang Zhu, Juxiang He, and Shengde Ouyang

Doc ID: 327875 Received 09 Apr 2018; Accepted 02 Jul 2018; Posted 03 Jul 2018  View: PDF

Abstract: The beam wander of a partially coherent Airy beam in oceanic turbulence is investigated with the help of theextended Huygens–Fresnel integral formula. Analytical expression for the second-order moment and the beamwander of a partially coherent Airy beam propagating in oceanic turbulence are derived. From the numericalresults which based on the analytical formula we find that increasing the dissipation rate of turbulent kineticenergy or decreasing the dissipation rate of mean-square temperature and relative strength of temperature andsalinity fluctuations of oceanic turbulence tend to decrease the wander effect of a partially coherent Airy beam.Moreover, it is found that increasing the transverse scale factor and wavelength or decreasing the coherent lengthand exponential truncation factor of a partially coherent Airy beam decrease the beam wander in oceanicturbulence. Our results will be useful in optical underwater communications and laser defence.

The optical performance of a dielectric-metal-dielectric anti-reflective absorber structure

Viacheslav Medvedev, Vladimir Gubarev, and Christopher Lee

Doc ID: 330718 Received 02 May 2018; Accepted 02 Jul 2018; Posted 03 Jul 2018  View: PDF

Abstract: The absorption of electromagnetic radiation by a planar structure, consisting of a three-layer dielectric-metal-dielectric coating on a metal back-reflector is analysed. The conditions for total absorption are derived. Our analysis shows that, in contrast with bi-layer structures, the calculated layer thicknesses are feasible to fabricate for any metal. The proposed absorber design is of potential use in infrared, terahertz and longer wavelength detectors and for radiant energy harvesting devices.

Three-dimensional single-pixel imaging of incoherent light with spatiotemporally modulated illumination

Jeffrey Field, Keith Wernsing, Jeffrey Squier, and Randy Bartels

Doc ID: 329037 Received 23 Apr 2018; Accepted 28 Jun 2018; Posted 28 Jun 2018  View: PDF

Abstract: We derive analytic expressions for the three-dimensional coherent transfer function (CTF) and coherent spread function (CSF) for coherent holographic image reconstruction by phase transfer (CHIRPT) microscopy with monochromatic and broadband illumination sources. The 3D CSF and CTF were used to simulate CHIRPT images, and the results show excellent agreement with experimental data. We include a ray-tracing model of the CHIRPT microscope to show that, in general, complicated aberration phases need not be applied to the formalism to predict imaging results in the laboratory. Finally, we show that the formalism presented here for computing the CSF/CTF pair in CHIRPT microscopy can be readily extended to other forms of single-pixel imaging, such as spatial-frequency-modulated imaging (SPIFI).

Scintillation and bit error rate analysis of partially coherent flat-topped array laser beam in maritime and terrestrial non-Kolmogorov atmospheric environment on slant path

SHOLE GOLMOHAMMADY, bijan ghafary, Masoud Yousefi, and AHMAD MASHAL

Doc ID: 330267 Received 02 May 2018; Accepted 28 Jun 2018; Posted 28 Jun 2018  View: PDF

Abstract: In this paper, on the basis of the extended Huygens–Fresnel principle, a semi analytical expression for describingon-axis scintillation index of a partially coherent flat-topped (PCFT) laser beam through non-Kolmogorov maritime and terrestrial atmospheric environment on slant path is derived; consequently, by using the log-normal intensity probability density function, the bit error rate (BER) is evaluated. The effects of source factors (such as wavelength, order of flatness, and beam width) and the non- Kolmogorov turbulent atmosphere parameters (such as Kolmogorov inner scale, general spectral power-law exponent, the turbulence structure constant) on propagation behavior of scintillation index, and, hence, on BER, are studied in detail. Results indicate that, an increase in the average SNR causes a greater influence of the power-law exponent on BER. Also, it can be deduced that the mean bit error rate increases while the power-law exponent decreases. In addition, the scintillation index and BER as communication link parameters represent the fact that increasing the atmospheric refractive-index structure parameter on the ground and decreasing the inner scale of turbulence eddies causes an increase in theses parameters.

Solving large-scale general phase retrieval problemsvia a sequence of convex relaxations

R Doelman, Hieu Thao Nguyen, and Michel Verhaegen

Doc ID: 324747 Received 23 Feb 2018; Accepted 27 Jun 2018; Posted 27 Jun 2018  View: PDF

Abstract: We present a convex relaxation-based algorithm for large-scale general phase retrieval problems. Generalphase retrieval problems include i.a. the estimation of the phase of the optical field in the pupilplane based on intensity measurements of a point source recorded in the image (focal) plane. The nonconvexproblem of finding the complex field that generates the correct intensity is reformulated into arank constraint problem. The nuclear norm is used to obtain the convex relaxation of the phase retrievalproblem. A new iterative method, indicated as Convex Optimization-based Phase Retrieval (COPR), ispresented, with each iteration consisting of solving a convex problem. In the noise-free case and for aclass of phase retrieval problems the solutions of the minimization problems converge linearly or fastertowards a correct solution. Since the solutions to nuclear norm minimization problems can be computedusing semidefinite programming, and this tends to be an expensive optimization in terms of scalability,we provide a fast ADMM algorithm that exploits the problem structure. The performance of the COPRalgorithm is demonstrated in a realistic numerical simulation study, demonstrating its improvements inreliability and speed with respect to state-of-the-art methods.

Scattering matrix of arbitrarily shaped objects:Combining Finite Elements and Vector Partial Waves

Guillaume Demesy, Jean-Claude Auger, and Brian Stout

Doc ID: 324982 Received 27 Feb 2018; Accepted 26 Jun 2018; Posted 27 Jun 2018  View: PDF

Abstract: We demonstrate the interest of combining Finite Element calculations with the Vector Partial Wave formulation(used in T-matrix and Mie theory) in order to characterize the electromagnetic scattering properties of isolatedindividual scatterers. This method consists of individually feeding the finite element problem with incident VectorPartial Waves in order to numerically determine the T-matrix elements of the scatterer. For a sphere and anspheroid, we demonstrate that this method determines the scattering matrix to high accuracy. Recurrence relationsfor a fast determination of the vector partial waves are given explicitly, and an open-source code allowingthe retrieval of the presented numerical results is provided.

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