Mössbauer surface-guided waves in media with space modulation of Mössbauer isotope concentration

1998 ◽  
Vol 5 (3) ◽  
pp. 946-948 ◽  
Author(s):  
V. A. Belyakov ◽  
Yu. M. Aivazian
Keyword(s):  
Electromagnetic Waves ◽  
Guided Waves ◽  
Homogeneous Medium ◽  
Resonant Interaction ◽  
Theoretical Studies ◽  
Bragg Scattering ◽  
Guided Mode ◽  
Isotope Concentration ◽  
Space Modulation ◽  
Periodic Space

Rapid progress in Mössbauer spectroscopy combined with synchrotron radiation (SR) makes it urgent to study the interaction of SR with structures which have a space modulation of the Mössbauer isotope concentration, and thereby to reveal new effects in this interaction. Presented here are theoretical studies of the Mössbauer surface-guided mode (MSGM) in such media. MSGMs are analogous to the well known surface-guided electromagnetic waves (SGEW) in periodic media. However, because of their resonant interaction with Mössbauer nuclei they reveal some qualitative peculiarities compared with the case of conventional SGEW. The MSGMs for the case of purely nuclear Bragg scattering of quanta at a plane interface between a homogeneous medium and a medium with a periodic space modulation of the Mössbauer isotope concentration are investigated theoretically. The conditions of MSGM existence and allowed spectral intervals for the MSGM and their dependence on the period of space modulation and the degree of medium enrichment by the Mössbauer isotope are found. It is shown that the allowed interval of the MSGM frequencies is located at one side relative to the exact Mössbauer resonant frequency. Its width is of the order of the Mössbauer line width and can be effectively changed by the variation of the modulation period or the Mössbauer isotope concentration. For the MSGM frequencies close to the boundary of the MSGM existence interval, the attenuation of an MSGM propagating along the interface may be essentially lower than the conventional Mössbauer radiation attenuation in the same medium. The possibilities of SR Mössbauer filtration by means of MSGM are briefly discussed.

Surface electromagnetic waves at the interface between a homogeneous medium and a system of coupled waveguides

2008 ◽  
Vol 105 (4) ◽  
pp. 585-590 ◽  
Author(s):  
B. A. Usievich ◽  
J. Kh. Nurligareev ◽  
V. V. Svetikov ◽  
V. A. Sychugov
Keyword(s):  
Electromagnetic Waves ◽  
Homogeneous Medium ◽  
Surface Electromagnetic Waves ◽  
Coupled Waveguides

NONRECIPROCAL ELECTROMAGNETIC DEVICES IN GYROMAGNETIC PHOTONIC CRYSTALS

2013 ◽  
Vol 28 (02) ◽  
pp. 1441010 ◽  
Author(s):  
ZHI-YUAN LI ◽  
RONG-JUAN LIU ◽  
LIN GAN ◽  
JIN-XIN FU ◽  
JIN LIAN
Keyword(s):  
Magnetic Field ◽  
Band Gap ◽  
Electromagnetic Waves ◽  
Experimental Studies ◽  
Magnetic Surface ◽  
Electromagnetic Properties ◽  
Edge States ◽  
Bragg Scattering ◽  
Electromagnetic Devices ◽  
Gap Opening

Gyromagnetic photonic crystal (GPC) offers a promising way to realize robust transport of electromagnetic waves against backscattering from various disorders, perturbations and obstacles due to existence of unique topological electromagnetic states. The dc magnetic field exerting upon the GPC brings about the time-reversal symmetry breaking, splits the band degeneracy and opens band gaps where the topological chiral edge states (CESs) arise. The band gap can originate either from long-range Bragg-scattering effect or from short-range localized magnetic surface plasmon resonance (MSP). These topological edge states can be explored to construct backscattering-immune one-way waveguide and other nonreciprocal electromagnetic devices. In this paper we review our recent theoretical and experimental studies of the unique electromagnetic properties of nonreciprocal devices built in GPCs. We will discuss various basic issues like experimental instrumental setup, sample preparations, numerical simulation methods, tunable properties against magnetic field, band degeneracy breaking and band gap opening and creation of topological CESs. We will investigate the unidirectional transport properties of one-way waveguide under the influence of waveguide geometries, interface morphologies, intruding obstacles, impedance mismatch, lattice disorders, and material dissipation loss. We will discuss the unique coupling properties between one-wave waveguide and resonant cavities and their application as novel one-way bandstop filter and one-way channel-drop filter. We will also compare the CESs created in the Bragg-scattering band gap and the MSP band gap under the influence of lattice disorders. These results can be helpful for designing and exploring novel nonreciprocal electromagnetic devices for optical integration and information processing.

Analysis for Scattering of Non-homogeneous Medium by Time Domain Volume Shooting and Bouncing Rays

2021 ◽  
Vol 36 (3) ◽  
pp. 245-251
Author(s):  
Jun Li ◽  
Huaguang Bao ◽  
Dazhi Ding
Keyword(s):  
Time Domain ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
High Efficiency ◽  
Homogeneous Medium ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Transient Electromagnetic ◽  
Frequency Domain Methods ◽  
Scattered Fields

In order to evaluate scattering from hypersonic vehicles covered with the plasma efficiently, time domain volume shooting and bouncing rays (TDVSBR) is first introduced in this paper. The new method is applied to solve the transient electromagnetic scattering from complex targets, which combines with non-homogeneous dielectric and perfect electric conducting (PEC) bodies. To simplify the problem, objects are discretized into tetrahedrons with different electromagnetic parameters. Then the reflection and transmission coefficients can be obtained by using theory of electromagnetic waves propagation in lossy medium. After that, we simulate the reflection and transmission of rays in different media. At last, the scattered fields or radiation are solved by the last exiting ray from the target. Compared with frequency-domain methods, time-domain methods can obtain the wideband RCS efficiently. Several numerical results are given to demonstrate the high efficiency and accuracy of this proposed scheme.

scholarly journals Coherently Driven and Superdirective Antennas

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 845 ◽  
Author(s):  
Alex Krasnok
Keyword(s):  
Dielectric Resonator ◽  
Electromagnetic Waves ◽  
Wireless Power Transfer ◽  
Higher Order ◽  
Power Transfer ◽  
Wireless Power ◽  
Entire Spectrum ◽  
Guided Mode ◽  
Dielectric Antennas ◽  
Antenna Systems

Antennas are crucial elements for wireless technologies, communications and power transfer across the entire spectrum of electromagnetic waves, including radio, microwaves, THz and optics. In this paper, we review our recent achievements in two promising areas: coherently enhanced wireless power transfer (WPT) and superdirective dielectric antennas. We show that the concept of coherently enhanced WPT allows improvement of the antenna receiving efficiency by coherent excitation of the outcoupling waveguide with a backward propagating guided mode with a specific amplitude and phase. Antennas with the superdirectivity effect can increase the WPT system’s performance in another way, through tailoring of radiation diagram via engineering antenna multipoles excitation and interference of their radiation. We demonstrate a way to achieve the superdirectivity effect via higher-order multipoles excitation in a subwavelength high-index spherical dielectric resonator supporting electric and magnetic Mie multipoles. Thus, both types of antenna discussed here possess a coherent nature and can be used in modern intelligent antenna systems.

MATHEMATICAL ANALYSIS OF ELASTIC SURFACE WAVES IN TOPOGRAPHIC WAVEGUIDES

1999 ◽  
Vol 09 (05) ◽  
pp. 755-798 ◽  
Author(s):  
A. S. BONNET-BEN DHIA ◽  
J. DUTERTE ◽  
P. JOLY
Keyword(s):  
Free Surface ◽  
Half Space ◽  
Guided Waves ◽  
Transverse Energy ◽  
Eigenvalue Problems ◽  
Low Frequency ◽  
Elastic Half Space ◽  
High Frequencies ◽  
Guided Mode ◽  
Adjoint Operators

We present here a theoretical study of the guided waves in an isotropic homogeneous elastic half-space whose free surface has been deformed. The deformation is supposed to be invariant in the propagation direction and localized in the transverse ones. We show that finding guided waves amounts to solving a family of 2-D eigenvalue problems set in the cross-section of the propagation medium. Then using the min-max principle for non-compact self-adjoint operators, we prove the existence of guided waves for some particular geometries of the free surface. These waves have a smaller speed than that of the Rayleigh wave in the perfect half-space and a finite transverse energy. Moreover, we prove that the existence results are valid for arbitrary high frequencies in the presence of singularities of the free boundary. Finally, we prove that no guided mode can exist at low frequency, except maybe the fundamental one.

scholarly journals Theory of Nonlinear Guided Electromagnetic Waves in a Plane Two-Layered Dielectric Waveguide

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Valeria Yu. Kurseeva ◽  
Dmitry V. Valovik
Keyword(s):  
Electromagnetic Waves ◽  
Dielectric Waveguide ◽  
Guided Waves ◽  
Transverse Electric ◽  
Nonlinear Eigenvalue Problem ◽  
Discontinuous Coefficients ◽  
Wave Propagation Problem ◽  
Propagation Regime ◽  
Homogeneous Plane ◽  
Layered Dielectric

Propagation of transverse electric electromagnetic waves in a homogeneous plane two-layered dielectric waveguide filled with a nonlinear medium is considered. The original wave propagation problem is reduced to a nonlinear eigenvalue problem for an equation with discontinuous coefficients. The eigenvalues are propagation constants (PCs) of the guided waves that the waveguide supports. The existence of PCs that do not have linear counterparts and therefore cannot be found with any perturbation method is proven. PCs without linear counterparts correspond to a novel propagation regime that arises due to the nonlinearity. Numerical results are also presented; the comparison between linear and nonlinear cases is made.

Nonlinear interaction between three ordinary electromagnetic modes

1977 ◽  
Vol 17 (1) ◽  
pp. 51-55
Author(s):  
P. Muñoz ◽  
S. Dagach
Keyword(s):  
Magnetic Field ◽  
Normal Mode ◽  
Drift Velocity ◽  
Coupling Coefficient ◽  
Constant Magnetic Field ◽  
Nonlinear Interaction ◽  
Electromagnetic Waves ◽  
Resonant Interaction ◽  
Lagrangian Method

In this paper we consider the resonant interaction between three modified ordinary electromagnetic waves, which propagate perpendicular to a constant magnetic field. We show that for the modified mode to be a normal mode we must have the unperturbed current equal to zero. Using the averaged Lagrangian method, we calculate the coupling coefficient for the resonant interaction between three of these modes. It is proportional only to the cube of the drift velocity, as expected from the vanishing of the unperturbed current.

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