scholarly journals Light Scattering by a Subwavelength Plasmonic Array: Anisotropic Model

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 449
Author(s):  
Anton Nemykin ◽  
Leonid Frumin ◽  
David Shapiro
Keyword(s):  
Cross Sections ◽  
Total Internal Reflection ◽  
Light Transmission ◽  
Quantitative Agreement ◽  
Approximate Analytical Expression ◽  
Axis Ratio ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
The Media ◽  
Derivatives Of

We calculate the light transmission by a subwavelength plasmonic array using the boundary element method for parallel cylinders with different cross-sections: circular or elliptic with axis ratio 4:1. We demonstrate that plasmonic resonance is sharper for the case of horizontal ellipses. This structure is susceptible to refractive index variations in the media since the high derivatives of reflection and transmission coefficients are near the angle of total internal reflection. To obtain an approximate analytical expression, we used the model of a metallic layer. We explore the “sandwich” structure with an anisotropic film between two dielectrics and demonstrate its quantitative agreement with numerical results.

SS-traveltime parameters from PP and PS reflections

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. R35-R47 ◽  
Author(s):  
Bjørn Ursin ◽  
Martin Tygel ◽  
Einar Iversen
Keyword(s):  
Velocity Model ◽  
Ocean Bottom ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Partial Reconstruction ◽  
Propagator Matrix ◽  
Geometric Spreading ◽  
Derivatives Of ◽  
Full Simulation ◽  
Original Formula

The SS-wave traveltimes can be derived from PP- and PS-wave data with the previously derived [Formula: see text] method. We have extended this method as follows. (1) The previous requirement that sources and receivers be located on a common acquisition surface is removed, which makes the method directly applicable to PS-waves recorded on the ocean bottom and PP-waves recorded at the ocean surface. (2) By using the concept and properties of surface-to-surface propagator matrices, the second-order traveltime derivatives of the SS-waves are obtained. In the same way as for the original [Formula: see text] method, the proposed extension is valid for arbitrary anisotropic media. The propagator matrix and geometric spreading of an SS-wave reflected at a given point on a target reflector are obtained explicitly from the propagators of the PP- and PS-waves reflected at the same point. These additional parameters provided by the extended [Formula: see text] method can be used for a partial reconstruction of the SS-wave amplitude as well as for tomographic estimation of the elastic velocity model. A full simulation of the SS-wave, which includes reflection and transmission coefficients, cannot be obtained directly from recorded PP- and PS-wave amplitudes.

Propagation of acoustic waves in layered porous media

2007 ◽  
Vol 5 ◽  
pp. 169-175
Author(s):  
V.L. Dmitriev ◽  
Е.А. Ponomareva
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Dispersion Relation ◽  
Acoustic Waves ◽  
Saturated Liquid ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Layered Porous Media ◽  
The Media

The paper considers the processes of reflection and transmission acoustic waves at the interface between two porous media, saturated liquid or gas. The cases of a porous medium whose layers have the same porosity, but are saturated with different fluids. Based The dispersion relation and the conditions at the interface between the media are obtained reflection and transmission coefficients. The possibility determination of the parameters of the porous material and its saturating fluid based on the signal reflected from the interface.

scholarly journals Phonon Conductance of Potassium- and Sodium-Doped Transpolyacetylene Chain

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
M. Belhadi ◽  
S. Kheffache
Keyword(s):  
Cross Sections ◽  
Nearest Neighbor ◽  
Unit Cell ◽  
Cell Boundary ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Translation Symmetry ◽  
Scattering Spectra ◽  
Coherent Reflection ◽  
Scattering Cross Sections

A theoretical approach for the study of phonon dynamics and scattering properties of doped transpolyacetylene chain is presented. The coherent reflection and transmission scattering cross-sections for phonons incident on the doped unit cell boundary are calculated in accordance with the Landauer-Buttiker electron scattering description, using the matching procedure with the nearest and next nearest neighbor elastic force constants. This is done for two different dopants, namely, the potassium and sodium atoms. Our numerical results yield an understanding of the transpolyacetylene chain dynamical properties and the effects on phonon conductance due to phonon incident on the doped unit cell boundary. The coherent reflection and transmission coefficients show characteristic spectral features, depending on the cutoff frequencies for the propagating phonons and on the nature of the dopants. They illustrate the occurrence of Fano resonances in the scattering spectra that result from the interactions of propagating elastic waves of the undoped transpolyacetylene chain with the localized modes due to the breakdown of the translation symmetry in the x direction.

scholarly journals Reflection/refraction of SH-waves at a corrugated interface between two different anisotropic and vertically heterogeneous elastic solid half-spaces

2003 ◽  
Vol 44 (3) ◽  
pp. 447-460 ◽  
Author(s):  
Rajneesh Kumar ◽  
Sushil K. Tomar ◽  
Asha Chopra
Keyword(s):  
Closed Form ◽  
Order Approximation ◽  
Elastic Solid ◽  
Transversely Isotropic ◽  
Reflection And Transmission ◽  
Sh Waves ◽  
First Order ◽  
Transmission Coefficients ◽  
The Media ◽  
First Order Approximation

AbstractWe investigate the reflection and transmission of SH-waves at a corrugated interface between two different anisotropic, heterogeneous elastic solid half-spaces. Both the media are assumed to be transversely isotropic and vertically heterogeneous. Rayleigh's method is followed and expressions for the reflection and transmission coefficients are obtained in closed form for the first-order approximation of the corrugation. It is found that these coefficients depend on corrugation and are affected by the anisotropy and heterogeneity of the media. Numerical computations for a particular model have been performed.

Long wavelength superluminal pulse propagation in a defect slab doped with GaAs/AlGaAs multiple quantum well nanostructure

2015 ◽  
Vol 29 (33) ◽  
pp. 1550216 ◽  
Author(s):  
M. Panahi ◽  
G. Solookinejad ◽  
E. Ahmadi Sangachin ◽  
S. H. Asadpour
Keyword(s):  
Quantum Wells ◽  
Pulse Propagation ◽  
Light Transmission ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Reflection And Transmission ◽  
Long Wavelength ◽  
Transmission Coefficients ◽  
Nonresonance Condition ◽  
Excitonic States

In this paper, long wavelength superluminal and subluminal properties of pulse propagation in a defect slab medium doped with four-level GaAs/AlGaAs multiple quantum wells (MQWs) with 15 periods of 17.5 nm GaAs wells and 15 nm [Formula: see text] barriers is theoretically discussed. It is shown that exciton spin relaxation (ESR) between excitonic states in MQWs can be used for controlling the superluminal and subluminal light transmissions and reflections at different wavelengths. We also show that reflection and transmission coefficients depend on the thickness of the slab for the resonance and nonresonance conditions. Moreover, we found that the ESR for nonresonance condition lead to superluminal light transmission and subluminal light reflection.

Propagation of Stress Gradient Through an Inclusion—Part 1

1973 ◽  
Vol 40 (3) ◽  
pp. 711-717 ◽  
Author(s):  
T. C. T. Ting ◽  
Shun-Chin Chou
Keyword(s):  
Composite Materials ◽  
Wave Front ◽  
Incident Wave ◽  
Stress Gradient ◽  
Higher Order ◽  
Elastic Media ◽  
Interface Boundary ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Derivatives Of

This is the first of a two-part study on the propagation of stress gradient in composite materials. Both the plane-strain and axisymmetric motions are considered. In this paper, the reflection and transmission coefficients are derived for the stress, the stress gradient, and the higher-order derivatives of stress at an interface between two elastic media. It is shown that while the reflection and transmission of the stress do not depend on the geometries of the incident wave front and the interface boundary, the reflection and transmission of the stress gradient, and the higher-order derivatives of stress do depend on these geometries. Explicit expressions are derived for the reflection and transmission of the stress gradient in terms of the radii of curvatures of the incident wave front and the interface boundary.

Extension of forward modeling phase-screen code in isotropic and anisotropic media up to critical angle

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. SM107-SM114 ◽  
Author(s):  
James C. White ◽  
Richard W. Hobbs
Keyword(s):  
Critical Angle ◽  
Model Space ◽  
Anisotropic Media ◽  
Forward Modeling ◽  
Phase Screen ◽  
Computationally Efficient ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Phase Corrections ◽  
Converted Phases

The computationally efficient phase-screen forward modeling technique is extended to allow investigation of nonnormal raypaths. The code is developed to accommodate all diffracted and converted phases up to critical angle, building on a geometric construction method. The new approach relies upon prescanning the model space to assess the complexity of each screen. The propagating wavefields are then divided as a function of horizontal wavenumber, and each subset is transformed to the spatial domain separately, carrying with it angular information. This allows both locally accurate 3D phase corrections and Zoeppritz reflection and transmission coefficients to be applied. The phase-screen code is further developed to handle simple anisotropic media. During phase-screen modeling, propagation is undertaken in the wavenumber domain where exact expressions for anisotropic phase velocities are available. Traveltimes and amplitude effects from a range of anisotropic shales are computed and compared with previous published results.

Radical schemes for the implementation of section structures of the RADICAL language when modeling complex purposeful system

2021 ◽  
Author(s):  
M.V. Pirogov
Keyword(s):  
Complex System ◽  
Cross Sections ◽  
Problem Area ◽  
Information Support ◽  
Existing Problems ◽  
Modeling Technology ◽  
Universal Language ◽  
The Media ◽  
Modeling Complex System ◽  
Automation Tools

Complex artificial purposeful systems and their software and hardware are characterized not only by achievements, but also disadvantages leading to significant losses. Modern automation tools do not fully cope with the existing problems. To solve the problems of complex systems, new effective tools are needed, new modeling technology. This technology should cover all significant aspects of the problem area. It seems that such technology should be based on radical modeling and the universal language of radical schemes RADICAL. A radical is a system characterized by both active (working) and passive states. Being connected with each other radicals form schemes of radicals. These schemes are constructions of the RADICAL language. In the aggregate, these schemes realize radical environment – radical model of united problem area of complex system. That is, the problem area is represented by a single global scheme of radicals. The work with such a scheme is carried out using the universal language of radical schemes RADICAL, applicable to the problem area of any complex system by constructing sections of the RADICAL language, expressed by the schemes of radicals. The purpose of the work is to consider the use of radical schemes for the implementation of the structures of sections (sequences of sections) of the RADICAL language when modeling complex system. The results of the work are descriptions of some typical schemes of radicals intended for the implementation of the section structures of the RADICAL language when modeling complex purposeful systems. Something significant sequences of sections are considered. The practice of using of structures of cross-sections of the media of radicals, expressed by the schemes of radicals, indicates the expediency of they use for radical modeling of problem areas of complex purposeful systems, for the development and modification of software and information support of such systems.

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