Transverse Electromagnetic Field Research Articles

Nanorod Size Dependence of Coherent Coupling between Individual and Collective Excitations via Transverse Electromagnetic Field

Nanorod Size Dependence of Coherent Coupling between Individual and Collective Excitations via Transverse Electromagnetic Field

Detailed analysis for temperature-dependent and temperature-independent Goos–Hänchen shift

In this work, we have presented the deep insight of Goos–Hänchen shift depending upon the temperature when a plane incident electromagnetic beam of light enters from a rare to a denser medium, keeping conditions of total internal reflection intact. A simple well known Drude’s model has been used for the purpose of thermal analysis of this shift. Through this model, the temperature-dependent permittivity of absorbing or complex medium has been found through the temperature-dependent plasma and damping wavelengths. Both transverse electric and magnetic incident electromagnetic fields have been considered in this regard. On an air–metal interface, firstly, Goos–Hänchen shift has been found when a temperature-independent dielectric function of a complex medium has been considered, and secondly, by analyzing the temperature-dependent dielectric function in the simplest way by using the stationary-phase method. This study is useful to understand the behavior of Goos–Hänchen shift around the temperature-dependency of the medium and how the angle of incidence impacts in this scenario.

Anomalous magnetohydrodynamics with temperature-dependent electric conductivity and application to the global polarization

We have derived the solutions of the relativistic anomalous magnetohydrodynamics with longitudinal Bjorken boost invariance and transverse electromagnetic fields in the presence of temperature or energy density dependent electric conductivity. We consider the equations of states in a high temperature limit or in a high chiral chemical potential limit. We obtain both perturbative analytic solutions up to the order of \hbar and numerical solutions in our configurations of initial electromagnetic fields and Bjorken flow velocity. Our results show that the temperature or energy density dependent electric conductivity plays an important role to the decaying of the energy density and electromagnetic fields. We also implement our results to the splitting of global polarization for \Lambda and \bar{\Lambda} hyperons induced by the magnetic fields. Our results for the splitting of global polarization disagree with the experimental data in low energy collisions, which implies that the contribution from gradient of chemical potential may dominate in the low energy collisions.

Assessment of Photon Recycling in Perovskite Solar Cells by Fully Coupled Optoelectronic Simulation

An optical dyadic Green's function framework to describe the transverse electromagnetic fields in a planar perovskite solar-cell stack is coupled to an electronic drift-diffusion model for rigorous treatment of photon recycling in the wave-optics regime for a realistic photovoltaic device. The optical model provides the local reabsorption rate as well as a detailed-balance compatible radiative prefactor, which are used in the electronic model to achieve a self-consistent solution that yields the full optoelectronic device characteristics. The presented approach provides detailed insights into the impact of photon recycling on device performance under different regimes of charge transport and recombination and can help identify the various electronic and optical losses for nonideal, realistic devices. The global efficiency of photon recycling is quantified by defining quantum efficiencies of reabsorbed radiation, while the local efficiency can furthermore be quantified by defining an effective local radiative prefactor. The model introduced here can be used to guide the design of future devices that exploit the full potential of photon recycling.

Kinetic Alfven Waves Near a Dissipative Layer

AbstractThe spatial structure of kinetic Alfven waves near a dissipative layer is examined. The type of dispersion for kinetic Alfven waves (KAWs) changes inside the dissipative layer: from ”cold,” when the transverse (across the magnetic shells) wavelength is determined by the electron skin depth in plasma, to ”warm” dispersion, when the wavelength is determined by the ion Larmor radius. The characteristic transverse length of a KAW is complex in the dissipative layer, because it decays strongly when interacting with background plasma electrons. The features of phase shifts between the transverse electromagnetic field components of Alfven oscillations are considered. Phase shift can be used to identify the type of Alfven waves observed by satellites in the vicinity of the dissipative layer. The Alfven wave energy absorption in the dissipative layer can lead to the formation of electron fluxes (with electron energies of 2–5 eV) toward the ionosphere and initiate here the stable auroral red (SAR) arcs. An analytical formula is proposed for determining the density of the electron flux toward the ionosphere and the flux of the energy transferred by them.

Acceleration of heavy ions in inverse free electron laser

In conventional linear accelerators, the beam is accelerated with a synchronous harmonic of the radio frequency field where the electric field component is collinear with the beam direction. This approach requires the design of complex accelerating structures, especially for low-energy heavy ions. If the beam motion were sustainably coupled to transverse electromagnetic fields, this could significantly simplify the accelerating structure design, and even allow acceleration with free-space waves. However, despite the long history of the proposed concept for accelerating low-velocity ion beams, it has not found practical application, partially because of the complexity of the technical design. In this paper, we present a practical design approach for this undulator-based accelerator for low-energy heavy-ions, reminiscent of the inverse free electron laser operating principle, but in a different parameter space.

Maxwell’s electrodynamics including spin and chirality

Maxwell electrodynamics and its modification are derived using quaternionic formulation. Starting from the quaternionic Maxwell’s equation, all subsequent equations are derived in a very succinct way. The energy, momentum, and spin angular momentum conservation equations are defined for quaternionic electrodynamics. Using the modified electrodynamics, we formally derive London’s equations of superconductivity without recourse to Newton’s second law of motion. The modified electrodynamics allows a longitudinal scalar field to arise besides the transverse electromagnetic field. The influence of the scalar field is manifested in several phenomena we already encountered but we have incorporated such effects in the framework of Maxwell’s electrodynamics. The non-uniformity and inhomogeneity of the medium, in which the electromagnetic field exists, affects the electromagnetic properties of the system in the way how the scalar field vary in space and time. Two different scenarios for quantum massive electrodynamics are proposed. One of the scenarios reduces to axion electrodynamics which further reduces to Maxwell–Proca massive boson electrodynamics. A quantum massive electrodynamic is studied and found not to alter the beauty of Maxwell’s electrodynamics. Additional electric and magnetic charge densities are found to be induced with non-dissipative currents.

Multimillijoule terahertz radiation from laser interactions with microplasma waveguides

When a relativistic, femtosecond laser pulse enters a waveguide, the pulse energy is coupled into waveguide optical modes. The longitudinal laser field effectively accelerates electrons along the axis of the channel, while the asymmetric transverse electromagnetic fields tend to expel fast electrons radially outwards. At the exit of the waveguide, the ∼nC, ∼10 MeV electron bunch converts its energy to a ∼10 mJ terahertz (THz) laser pulse through coherent diffraction radiation. In this paper, we present 3D particle-in-cell simulations and theoretical analyses of the aforementioned interaction process. We investigate the process of longitudinal acceleration and radial expulsion of fast electrons, as well as the dependence of the properties of the resulting THz radiation on laser and plasma parameters and the effects of the preplasma. The simulation results indicate that the conversion efficiency of energy can be over 5% if the waveguide length is optimal and a high contrast pump laser is used. These results guide the design of more intense and powerful THz sources.

АНАЛИЗ ЭЛЕКТРОМАГНИТНЫХ И ТЕПЛОВЫХ ПОЛЕЙ В РАБОЧЕМ ЗАЗОРЕ ИНДУКТОРА ДЛЯ НАГРЕВА МЕТАЛЛИЧЕСКИХ ИЗДЕЛИЙ В ПОПЕРЕЧНОМ ЭЛЕКТРОМАГНИТНОМ ПОЛЕ

The article discusses the results of theoretical and experimental studies of the nature of the distribution of the main parameters of the electromagnetic field in the working gap of the inductor for heating magnetic and non-magnetic materials in a transverse magnetic field performed by the analytical method and using computer simulation in the ELCUT software environment. The results obtained can be useful for specialists, both in the design of induction devices for heating flat magnetic and non-magnetic materials in a transverse electromagnetic field, taking into account the change in their electrophysical properties, and during the operation of installations for diagnosing the quality of electromagnetic and thermal fields.

Reflection and Transmission Coefficients in Multilayered Fully Anisotropic Media Solved by Transfer Matrix Method With Plane Waves for Predicting Energy Transmission Course

In this article, we rapidly and accurately solve out reflection and transmission coefficients in the multilayered fully anisotropic media (MFAM) based on the transfer-matrix method (TMM) so that we could find out the energy transmission course (ETC) of plane waves that transmit through MFAM in the air background. Beginning with Maxwell's equations, MFAM's Helmholtz equation could be obtained by the known transverse- k vectors of plane waves. Through a series of complicated manipulations applied to the derivation of Helmholtz equations, we can attain ordinary differential equation of electric fields that merely exist in a certain direction and then compute four different eigenvalues in different MFAM regions. Under 3-D cases, meanwhile, concrete expressions of other fields can be obtained by given electric fields in the fixed direction. The ETC of electromagnetic fields in the tangential continuity is mainly considered in the TMM, and hence, the transferring matrix of electromagnetic field between MFAM regions can be constructed to achieve reflection and transmission coefficients. With various plane-wave modes such as transverse electromagnetic (TEM), transverse electric (TE), and transverse magnetic (TM) field modes, respectively, computational results of MFAM models are solved and adopted to compare with those from the commercial software of COMSOL. Finally, to discuss deeply and efficiently achieve color images, we acquire those reflection and transmission coefficients of more complicated fully anisotropic materials under the different transverse- k vectors. Our work can be an efficient and reliable solver for excavating prospective applications to predict ETC of models with single-layered/multilayered materials possessing fully anisotropy.

Near-atomically flat, chemically homogeneous, electrically conductive optical metasurface.

Metasurfaces, or two-dimensional arrays of subwavelength-scale structures, can exhibit extraordinary optical properties. However, typical metasurfaces have a bumpy surface morphology that may restrict their practical applications. Here, we propose and demonstrate an optical metasurface that is composed of a thin metallic film, with hidden dielectric structures underneath, and a metal back mirror layer. Exploiting the large difference between the Thomas-Fermi screening length for longitudinal electric fields and the skin depth for transverse electromagnetic fields, the near-atomically flat top surface of the proposed structure can appear homogeneous chemically and electrically but highly inhomogenous optically. The size and shape of the hidden dielectric structures as well as the thickness of the top metallic layer can be tailored to acquire desired optical properties. We performed both theoretical and experimental studies of the proposed metasurface, finding a good agreement between them. This work provides a new platform for ultra-flat optical devices, such as a wavelength selective electrode, diffusive back reflector, meta-lens, and plasmonically enhanced optical biosensors.

Atomic and Molecular Processes in a Strong Bicircular Laser Field

With the development of intense femtosecond laser sources it has become possible to study atomic and molecular processes on their own subfemtosecond time scale. Table-top setups are available that generate intense coherent radiation in the extreme ultraviolet and soft-X-ray regime which have various applications in strong-field physics and attoscience. More recently, the emphasis is moving from the generation of linearly polarized pulses using a linearly polarized driving field to the generation of more complicated elliptically polarized polychromatic ultrashort pulses. The transverse electromagnetic field oscillates in a plane perpendicular to its propagation direction. Therefore, the two dimensions of field polarization plane are available for manipulation and tailoring of these ultrashort pulses. We present a field that allows such a tailoring, the so-called bicircular field. This field is the superposition of two circularly polarized fields with different frequencies that rotate in the same plane in opposite directions. We present results for two processes in a bicircular field: High-order harmonic generation and above-threshold ionization. For a wide range of laser field intensities, we compare high-order harmonic spectra generated by bicircular fields with the spectra generated by a linearly polarized laser field. We also investigate a possibility of introducing spin into attoscience with spin-polarized electrons produced in high-order above-threshold ionization by a bicircular field.

The Nature of the Photon and Quantum Optics

In a concise, but accessible for the first acquaintance form the procedure for the quantization of linear oscillator is set out. By analogy with this procedure the procedure of quantization (second quantization) of classical Maxwell’s electrodynamics is set up. The physical sense of the wave functions arguments of transverse electromagnetic field and its Fourier transformation is set up. One pay attention as for quantum coherent (almost a classic) states of the electromagnetic field and for photonics Fock states. Attention is drawn to the fact of absence the power of the universal content of such concepts as field amplitude, phase and number of particles (photons), which are used by experimenter’s to describe the states of a quantized field. The semi quantitative description the interaction processes of a quantum electromagnetic field with substance is set up. Specified situations are shown in which the discrepancy between the predictions of classical and quantum electrodynamics is noticeable at the macroscopic level.

Quantum description of a field in macroscopic electrodynamics and photon properties in transparent media

Applying a quantum mechanical treatment to a high-frequency macroscopic electromagnetic field and radiative phenomena in a medium, we construct quantum operators for energy–momentum tensor components in dispersive media and find their eigenvalues, which are different in the Minkowski and Abraham representations. It is shown that the photon momentum in a medium resulting from the quantization of the vector potential differs from that defined from Abraham’s symmetric energy–momentum-tensor but is equal to the momentum defined from the Minkowski tensor. A similar result is obtained by calculating the intrinsic angular momentum (spin) of an electro-magnetic field in the medium. Only the Minkowski tensor leads to the experimentally confirmed spin values that are multiples of ħ, providing the grounds for choosing the Minkowski representation as the proper form for the momentum density of a transverse electromagnetic field in a transparent medium, in both classical and quantum descriptions of the field. The Abraham representation is unsuitable for this purpose and leads to contradictions. The conclusion drawn does not apply to quasistatic and static fields.

Invariant superoscillatory electromagnetic fields in 3D-space

We derive exact solutions of Maxwell’s equations based on superoscillatory superpositions of vectorial Bessel beams. These novel beams are diffraction-free and can support subwavelength features in their transverse electromagnetic fields, without the presence of any evanescent waves. These features can be propagated into the far field. Approximate solutions in closed form are also derived based on asymptotic expansions of Bessel functions for simple prescribed subwavelength patterns. The superoscillatory characteristics of both electric, magnetic field components (transverse and longitudinal), and the Poynting vector, as well as, the effect of nonparaxiality are systematically investigated.

The effect of a longitudinal density gradient on electron plasma wake field acceleration

Three-dimensional, particle-in-cell, fully electromagnetic simulations of electron plasma wake field acceleration in the blow-out regime are presented. Earlier results are extended by (i) studying the effect of a longitudinal density gradient, (ii) avoiding the use of a co-moving simulation box, (iii) inclusion of ion motion, and (iv) studying fully electromagnetic plasma wake fields. It is established that injecting driving and trailing electron bunches into a positive density gradient of 10-fold increasing density over 10 cm long lithium vapour plasma results in spatially more compact and three times larger, compared with the uniform density case, electric fields (−6.4×10 10 V m −1 ), leading to acceleration of the trailing bunch up to 24.4 GeV (starting from an initial 20.4 GeV), with energy transfer efficiencies from the leading to trailing bunch of 75%. In the uniform density case, a −2.5×10 10 V m −1 wake is created leading to acceleration of the trailing bunch up to 22.4 GeV, with energy transfer efficiencies of 65%. It is also established that injecting the electron bunches into a negative density gradient of 10-fold decreasing density over 10 cm long plasma results in spatially more spread and two and a half smaller electric fields (−1.0×10 10 V m −1 ), leading to a weaker acceleration of the trailing bunch up to 21.4 GeV, with energy transfer efficiencies of 45%. Taking ion motions into consideration shows that in the plasma wake ion number density can increase over a few times the background value. It is also shown that transverse electromagnetic fields in a plasma wake are of the same order as the longitudinal (electrostatic) ones.

Generation of a longitudinal current by a transverse electromagnetic field in collisional degenerate plasma

From the Vlasov–Boltzmann kinetic equation for a collisional degenerate plasma, the electron distribution function is constructed in the quadratic approximation in the electric field strength. A formula for calculating the electric current is derived. It is shown that nonlinearity leads to the rise of a longitudinal electric current directed along the wave vector. The longitudinal current is orthogonal to the known transverse classical current obtained in the linear analysis. When the collision frequency tends to zero, all results obtained for a collisional plasma pass into the corresponding results for a collisionless plasma. The case of small wavenumbers is considered. It is shown that, when the collision frequency tends to zero, the expression for the current passes into the corresponding expression for the current in a collisionless plasma. Graphic analysis of the real and imaginary parts of the current density is performed. The dependence of the electromagnetic field oscillation frequency and electron–plasma-particle collision frequency on the wavenumber is studied.

Coupling to modes of a near-confocal optical resonator using a digital light modulator.

Digital micromirror devices (DMD) provide a robust platform with which to implement digital holography, in principle providing the means to rapidly generate propagating transverse electromagnetic fields with arbitrary mode profiles at visible and IR wavelengths. We use a DMD to probe a Fabry-Pérot cavity in single-mode and near-degenerate confocal configurations. Pumping arbitrary modes of the cavity is possible with excellent specificity by virtue of the spatial overlap between the incident light field and the cavity mode.

Longitudinal electric current generated by a transverse electromagnetic field in a collisional plasma

Kinetic Vlasov equation for collisional plasmas with BGK (Bhatnagar-Gross-Krook) collision integral is used. The case of arbitrary temperature (i.e. arbitrary degree of degeneration of electronic gas) is considered. From kinetic Vlasov equation the distribution function in square-law approximation on size of transversal electromagnetic field is received. The formula for calculation electric current is deduced. This formula contains one-dimension quadrature. It is shown, that the nonlinearity account leads to occurrence the longitudinal electric current directed along the wave vector. This longitudinal current is perpendicular to the known transversal classical current, received at the linear analysis. When frequency of collisions tends to zero, all received results for collisional plasma pass in known corresponding formulas for collisionless plasma. The case of small values of wave number is considered. It is shown, that the received quantity of longitudinal current at tendency of frequency of collisions to zero also passes in known corresponding expression of current for collisionless plasmas. Graphic research of dimensionless density of the current depending on wave number, frequency of oscillations of electromagnetic field and frequency of electron collisions with plasma particles is carried out.

A series of phonon-polaritons in a diatomic ionic crystal

The interaction between the harmonics of the optical phonon and the transverse wave of the electromagnetic field in ionic crystals with two atoms in the unit cell is considered. The Kun Huang model is used to describe the point charges sublattices that oscillate with a frequency ω0. The thermal motion of charges sublattices surrounding thermostat is taken into account. The local field is taken into account as well by introducing of an effective charge. A statistical operator of the system in a perturbation theory is introduced self-consistently small interaction is constructed. The new series of long-wave phonon-polaritons as the eigenwaves of the transverse electromagnetic field is obtained. The approximation is valid for a small ratio of the standard thermal deviation to the wavelength that allows to limit only the second and the third phonon harmonics in the dispersion equation at plotting the graph. A frequency line 2ω0 restricts the top of the first upper phonon-polariton graph and the bottom of the second upper phonon-polariton graph for the used example of cesium bromide crystal. The rest of the phonon-polaritons have graphs in the form of stairs with a slope, asymptotically approaching to the photon graph in this crystal, and with a height ω0.