scholarly journals Elusive Pure Anapole Excitation in Homogenous Spherical Nanoparticles with Radial Anisotropy

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Liu ◽  
Bing Lei ◽  
Jianhua Shi ◽  
Haojun Hu ◽  
Andrey E. Miroshnichenko
Keyword(s):  
Cross Section ◽  
Plane Waves ◽  
Far Field ◽  
Spherical Nanoparticles ◽  
Magnetic Dipoles ◽  
Anisotropic Dielectric ◽  
Scattered Power ◽  
Incident Plane ◽  
Total Scattering Cross Section ◽  
Radial Anisotropy

For homogenous isotropic dielectric nanospheres with incident plane waves, Cartesian electric and toroidal dipoles can be tunned to cancel each other in terms of far-field scattering, leading to the effective anopole excitation. At the same time however, other multipoles such as magnetic dipoles with comparable scattered power are simultanesouly excited, mixing with the anopole and leading to a nonnegligible total scattering cross-section. Here, we show that, for homogenous dielectric nanospheres, radial anisotropy can be employed to significantly suppress the other multipole excitation, which at the same time does not compromise the property of complete scattering cancallation between Cartesian electric and toroidal dipoles. This enables an elusivepure anopoleexcitation within radially anisotropic dielectric nanospheres, which may shed new light on many scattering related fundamental researches and applications.

BACKSCATTERING FROM A CONDUCTING CYLINDER WITH A SURROUNDING SHELL

1960 ◽  
Vol 38 (12) ◽  
pp. 1665-1676 ◽  
Author(s):  
M. A. Plonus
Keyword(s):  
Cross Section ◽  
Propagation Constant ◽  
Scattering Cross Section ◽  
Graphical Form ◽  
Far Field ◽  
Scattering Cross ◽  
Conducting Cylinder ◽  
Incident Plane ◽  
Section Versus ◽  
Field Coefficient

Far-field backscattering from a perfectly conducting cylinder with a surrounding shell has been investigated. The spacing of the shell from the cylinder and thickness of the shell are arbitrary. The material in the shell is also arbitrary and is characterized by the propagation constant h. The incident plane wave is at right angles to the cylinder, and is either horizontally or perpendicularly polarized. When the shell is thin in units of wavelength a much simpler expression for the backscattered field coefficient is obtained. It was possible to express this coefficient in a form which resembles the coefficient from the conducting cylinder alone plus a perturbation term due to the shell. Another simplification resulted when the propagation constant h of the shell is much larger than the free-space propagation constant k.It was desirable to see what scattering properties a cylinder with a surrounding shell exhibits. The cylinder was chosen to be large with respect to wavelength and the shell spaced a resonant distance from the cylinder. The scattering cross section, for this particular combination of parameters was then given by a slowly converging series which proved too lengthy for hand-computation, and was then programmed for and computed by the IBM 704. The scattering cross section versus shell spacing is shown in graphical form.

scholarly journals Dual polarized engineering the extinction cross-section of a dielectric wire using graphene-based oligomers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shiva Hayati Raad ◽  
Zahra Atlasbaf
Keyword(s):  
Cross Section ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Infinite Length ◽  
Dielectric Cylinder ◽  
Fano Resonances ◽  
Spherical Nanoparticles ◽  
Extinction Cross Section ◽  
One Dimensional ◽  
Incident Plane

AbstractIn this paper, graphene-coated spherical nanoparticles are arranged around an infinite length dielectric cylinder to enhance its extinction cross-section. Initially, a single longitudinal one-dimensional periodic array is considered in different loci concerning the transverse electric (TE) incident plane wave. It is observed that regardless of the position of the particles, the extinction cross-section of the dielectric cylinder is considerably enhanced with respect to the bare one. Later, by increasing the number of longitudinal plasmonic arrays around the cylinder, each residing in a different azimuthal direction, the extinction cross-section is further manipulated to observe double pronounced Fano resonances. The origin of the Fano resonances is described by considering their planar counterparts constructed by the periodic assembly of plasmonic oligomers. Finally, the hexamer configuration is considered as the prototype, and the effect of various optical, geometrical, and material parameters on the optical response is investigated in detail. Interestingly, due to the spherical symmetry of the cells, the extinction cross-section is also enhanced for the transverse magnetic (TM) incident wave, which is unattainable using a continuous plasmonic cover made of metal or graphene. The potential application of our proposed structure is in the design of reconfigurable conformal optical absorbers and sensors.

scholarly journals An experimental realization of cylindrical cloaking using dogbone metamaterials

2017 ◽  
Vol 95 (10) ◽  
pp. 927-932 ◽  
Author(s):  
V.P. Sarin ◽  
M.P. Jayakrishnan ◽  
P.V. Vinesh ◽  
C.K. Aanandan ◽  
P. Mohanan ◽  
...  
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Research Community ◽  
Experimental Realization ◽  
The Past ◽  
Scattered Power ◽  
Incident Plane ◽  
Effective Reduction ◽  
Target Metal ◽  
Wave Incidence

The quest for invisibility has inspired a deep ardour in the research community over the past decade. The invention of metamaterials has boosted the research on electromagnetic cloaking due to its unusual electromagnetic parameters under plane wave incidence. In this study, we propose a novel cloaking scheme, using dogbone metamaterials, for effectively routing the incident electromagnetic fields around a target metal cylinder under consideration. Notable reduction in the scattered power is observed from the target in comparison to an uncloaked target. Experiments and simulations validate an effective reduction in the scattering cross section of the target and effective guiding of the incident plane wave around the target.

Acoustic Diffraction of a Plane Wave by Two Coplanar Parallel Perfectly Soft or Rigid Strips

1972 ◽  
Vol 50 (9) ◽  
pp. 928-939 ◽  
Author(s):  
D. L. Jain ◽  
R. P. Kanwal
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Normal Derivative ◽  
Field Amplitude ◽  
Far Field ◽  
Soft Or ◽  
Transmission Coefficients ◽  
Incident Plane ◽  
Acoustic Diffraction ◽  
Conducting Screen

The problem of diffraction of a normally incident plane acoustic wave by two parallel and coplanar infinite strips is considered. The assumed boundary conditions on the strips are the vanishing of either the total wave function or its normal derivative. Expressions are obtained for the first few terms of the series for the far-field amplitude and the scattering cross section when the wavelength is much larger than the distance between the outer edges of the strips. The corresponding results for two parallel and coplanar infinite slits in a soft or a rigid screen follow by applying Babinet's principle. This analysis also gives the transmission coefficients for the case of two infinite parallel slits in a thin conducting screen when the electric or magnetic field vectors of the incident plane monochromatic waves are polarized parallel to the edges of the slits.

scholarly journals A Tutorial on the Classical Theories of Electromagnetic Scattering and Diffraction

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 315-342
Author(s):  
Masud Mansuripur
Keyword(s):  
Cross Section ◽  
Electromagnetic Scattering ◽  
Final Section ◽  
Scattering Amplitude ◽  
Plane Waves ◽  
Homogeneous Medium ◽  
Far Field ◽  
Scalar Diffraction ◽  
Optical Cross Section ◽  
Section Theorem

AbstractStarting with Maxwell’s equations, we derive the fundamental results of the Huygens-Fresnel-Kirchhoff and Rayleigh-Sommerfeld theories of scalar diffraction and scattering. These results are then extended to cover the case of vector electromagnetic fields. The famous Sommerfeld solution to the problem of diffraction from a perfectly conducting half-plane is elaborated. Far-field scattering of plane waves from obstacles is treated in some detail, and the well-known optical cross-section theorem, which relates the scattering cross-section of an obstacle to its forward scattering amplitude, is derived. Also examined is the case of scattering from mild inhomogeneities within an otherwise homogeneous medium, where, in the first Born approximation, a fairly simple formula is found to relate the far-field scattering amplitude to the host medium’s optical properties. The related problem of neutron scattering from ferromagnetic materials is treated in the final section of the paper.

scholarly journals Localization of Scattering Objects Using Neural Networks

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 11
Author(s):  
Domonkos Haffner ◽  
Ferenc Izsák
Keyword(s):  
Neural Networks ◽  
Plane Waves ◽  
Measurement Data ◽  
Scattered Wave ◽  
Training Data ◽  
Data Set ◽  
Main Compound ◽  
Incident Plane ◽  
The Neural Networks ◽  
Simulation Package

The localization of multiple scattering objects is performed while using scattered waves. An up-to-date approach: neural networks are used to estimate the corresponding locations. In the scattering phenomenon under investigation, we assume known incident plane waves, fully reflecting balls with known diameters and measurement data of the scattered wave on one fixed segment. The training data are constructed while using the simulation package μ-diff in Matlab. The structure of the neural networks, which are widely used for similar purposes, is further developed. A complex locally connected layer is the main compound of the proposed setup. With this and an appropriate preprocessing of the training data set, the number of parameters can be kept at a relatively low level. As a result, using a relatively large training data set, the unknown locations of the objects can be estimated effectively.

scholarly journals On the scattering of fast neutrons by protons

1947 ◽  
Vol 191 (1025) ◽  
pp. 195-209 ◽  
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Cosmic Ray ◽  
Fast Neutrons ◽  
Meson Mass ◽  
Nuclear Forces ◽  
Total Scattering ◽  
Empirical Results ◽  
Meson Theory ◽  
Total Scattering Cross Section

The features of the scattering of fast neutrons by protons are calculated using the Møller- Rosenfeld version of the meson theory of nuclear forces. The experimental results of Occhialini & Powell are used to check the predicted angular distribution of the scattered particles and to determine the mass of the meson; the meson mass indicated is about 215 electronic masses, which agrees with the mass of cosmic ray mesons. The total scattering cross-section predicted by the theory agrees with the empirical results.

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