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Related papers: Preparing materials with a desired refraction coef…

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A method is proposed to create materials with a desired refraction coefficient, possibly negative one. The method consists of embedding into a given material small particles. Given $n_0(x)$, the refraction coefficient of the original…

Mathematical Physics · Physics 2009-11-13 A. G. Ramm

It is proposed to create materials with a desired refraction coefficient in a bounded domain $D\subset \R^3$ by embedding many small balls with constant refraction coefficients into a given material. The number of small balls per unit…

Mathematical Physics · Physics 2015-05-14 A. G. Ramm

A method is given for creating material with a desired refraction coefficient. The method consists of embedding into a material with known refraction coefficient many small particles of size $a$. The number of particles per unit volume…

Mathematical Physics · Physics 2015-05-14 A. G. Ramm

A recipe for creating materials with a desired refraction coefficient is implemented numerically. The following assumptions are used: \bee \zeta_m=h(x_m)/a^\kappa,\quad d=O(a^{(2-\kappa)/3}),\quad M=O(1/a^{2-\kappa}),\quad \kappa\in(0,1),…

Numerical Analysis · Mathematics 2010-02-19 Sapto W. Indratno , Alexander G. Ramm

A recipe is given for making materials with negative refraction in acoustics, i.e., materials in which the group velocity is directed opposite to the phase velocity. The recipe consists of injecting many small particles into a bounded…

Mathematical Physics · Physics 2009-11-13 A. G. Ramm

The problem of practical preparing small impedance particles with a prescribed boundary impedance is formulated and its importance in physics and technology is discussed. It is shown that if this problem is solved then one can easily…

Applied Physics · Physics 2017-09-08 A. G. Ramm

Asymptotic solution to many-body wave scattering problem is given in the case of many small scatterers. The small scatterers can be particles whose physical properties are described by the boundary impedances, or they can be small…

Mathematical Physics · Physics 2011-01-25 A. G. Ramm

A method is given for calculation of a distribution of small particles, embedded in a medium, so that the resulting medium would have a desired radiation pattern for the plane wave scattering by this medium.

Mathematical Physics · Physics 2007-05-23 A. G. Ramm

Basic ideas for creating wave-focusing materials by injecting small particles in a given material are described. The number of small particles to be injected around any point is calculated. Inverse scattering problem with fixed wavenumber…

Mathematical Physics · Physics 2008-05-19 A. G. Ramm

We present a method of creation of photonic structures whose optical spectrum of the reflection coefficient has an arbitrary shape and has predetermined features. We develop an algorithm for the construction of a photonic crystal structure,…

Optics · Physics 2023-05-16 S. E. Svyakhovskiy , N. I. Pyshkov

A numerical approach to the problem of wave scattering by many small particles is developed under the assumptions k<<1, d>>a, where a is the size of the particles and d is the distance between the neighboring particles. On the wavelength…

Computational Physics · Physics 2012-06-18 M. I. Andriychuk , A. G. Ramm

Novel optical phenomena, including electromagnetically induced transparency, slow light, superluminal light propagation, have recently been demonstrated in diverse physical implementations. These phenomena are challenging to realize in…

Optics · Physics 2007-12-03 Vikas Anant , Ayman F. Abouraddy , Karl K. Berggren

A numerical solution to the problem of wave scattering by many small particles is studied under the assumption k<<1, d>>a, where a is the size of the particles and d is the distance between the neighboring particles. Impedance boundary…

Computational Physics · Physics 2012-06-18 M. I. Andriychuk , A. G. Ramm

Negative refraction is known to occur in materials that simultaneously possess a negative electric permittivity and magnetic permeability; hence they are termed negative index materials. However, there are no known natural materials that…

Reflectometry is a technique that uses the light reflected by a sample to determine properties of the sample. Interferometric reflectometry uses interference between two beams, one of which is incident on ---and reflected back by--- a…

Optics · Physics 2019-10-10 Alexander Nahmad-Rohen , Wolfgang Langbein

Scattering properties of a material are changed when the material is injected with small acoustically soft particles. It is shown that its new scattering behavior can be understood as a solution of a potential scattering problem with the…

Mathematical Physics · Physics 2007-05-23 A. G. Ramm , S. Gutman

A numerical scheme is presented to solve the one source near field refractor problem to arbitrary precision and it is proved that the scheme terminates in a finite number of iterations. The convergence of the algorithm depends upon proving…

Numerical Analysis · Mathematics 2019-04-26 Cristian E. Gutiérrez , Henok Mawi

Scalar wave scattering by many small particles of arbitrary shapes with impedance boundary condition is studied. The problem is solved asymptotically and numerically under the assumptions a << d << lambda, where k = 2pi/lambda is the wave…

Numerical Analysis · Mathematics 2016-02-16 Alexander Ramm , Nhan Tran

X-ray single particle imaging involves the measurement of a large number of noisy diffraction patterns of isolated objects in random orientations. The missing information about these patterns is then computationally recovered in order to…

Image and Video Processing · Electrical Eng. & Systems 2020-05-25 Kartik Ayyer

Generative image models can produce convincingly real images, with plausible shapes, textures, layouts and lighting. However, one domain in which they perform notably poorly is in the synthesis of transparent objects, which exhibit…

Computer Vision and Pattern Recognition · Computer Science 2026-05-05 Yue Yin , Enze Tao , Dylan Campbell
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