Electromagnetic Dispersion Research Articles

Analysis and Application of the Electromagnetic Wave Propagation, Fields, and Dispersion Relation in an Elliptical Chiro Plasma Waveguide Immersed in Magnetized Plasma

AbstractThis research proposes and investigates an elliptical waveguide filled with chiro plasma as its core and magnetized plasma as its clad region. The clad region is in the constant infinite magnetic field, and its direction is the same as the wave propagation in the chiro plasma elliptical waveguide. The electromagnetic wave propagation in the considered waveguide is studied. The expressions for electromagnetic field components in the chiro plasma core and magnetized plasma cladding are derived. The dispersion relations for the hybrid modes are calculated considering appropriate boundary conditions at the chiro plasma and magnetized plasma interface. The behavior of the energy flux and the dispersion curves are numerically and graphically studied. It is seen that the magnitude of the power density decreases with the increase of the cyclotron frequency and it increases with the increase of the plasma frequency and supports power flow in the backward direction for the considered mode. Furthermore, it is shown higher values of the chirality parameter cause the magnitude of the power flux to increase in the backward direction.

Imaging beyond the surface region: Probing hidden materials via atomic force microscopy.

Probing material properties at surfaces down to the single-particle scale of atoms and molecules has been achieved, but high-resolution subsurface imaging remains a nanometrology challenge due to electromagnetic and acoustic dispersion and diffraction. The atomically sharp probe used in scanning probe microscopy (SPM) has broken these limits at surfaces. Subsurface imaging is possible under certain physical, chemical, electrical, and thermal gradients present in the material. Of all the SPM techniques, atomic force microscopy has entertained unique opportunities for nondestructive and label-free measurements. Here, we explore the physics of the subsurface imaging problem and the emerging solutions that offer exceptional potential for visualization. We discuss materials science, electronics, biology, polymer and composite sciences, and emerging quantum sensing and quantum bio-imaging applications. The perspectives and prospects of subsurface techniques are presented to stimulate further work toward enabling noninvasive high spatial and spectral resolution investigation of materials including meta- and quantum materials.

Observation of Two-dimensional Isotropic Double Dirac Cones in the Electromagnetic Dispersion Relation

We report on the first experimental observation of two-dimensional isotropic double Dirac cones in the electromagnetic dispersion relation, which were materialized by the accidental degeneracy of E1- and E2-symmetric eigenmodes on the Γ point of photonic crystals. We fabricated triangular-lattice photonic crystal slabs of the C6v symmetry on silicon-on-insulator wafers by electron beam lithography and examined their dispersion relation by high-resolution angle-resolved reflection spectroscopy in the mid-infrared range. We observed the characteristic linear dispersion of the double Dirac cones together with the polarization selection rules derived from the mode symmetries. All these observations agreed with numerical calculation of the dispersion relation and reflection spectra by the finite element method.

Electromagnetic extension of the Dory–Guest–Harris instability as a benchmark for Vlasov–Maxwell continuum kinetic simulations of magnetized plasmas

A closed-form integral representation of the electromagnetic dispersion relation for plasma waves propagating perpendicular to a magnetic field is derived. Growth rates and oscillation frequencies are calculated for several cases of the Dory–Guest–Harris instability and compared with those calculated from the usual electrostatic version of the dispersion relation. The comparisons show that the electromagnetic treatment more accurately identifies unstable configurations in plasmas with high beta, where the electrostatic dispersion relation predicts stability. Continuum kinetic simulations using the Washington approximate Riemann plasma framework confirm the theoretical calculations. The electromagnetic extension of the Dory–Guest–Harris instability provides a new benchmark problem for testing continuum kinetic simulations using the Vlasov–Maxwell plasma model, including for other numerical treatments such as particle-in-cell methods.

Investigating the Second Harmonic Generation in One-Dimensional Multi-layer Structure Consisting of Polar Ferroelectric Called 𝐋𝐢𝐓𝐚𝐎𝟑 Using the Transfer Matrix Method

The transfer matrix method is widely used to calculate the electromagnetic waves dispersion. In this paper, we have investigated the second harmonic generation in a one-dimensional structure including LiTaO3 ferroelectric. Using the transfer matrix method, we obtain the second harmonic efficiency. In this article, in the structure of nonlinear photonic crystals, the linear and nonlinear optical parameters are changed periodically, which causes the second harmonic conversion efficiency to be several times greater than the conversion efficiency of a nonlinear structure based on conventional quasi-phase matching (QPM). The reason for this is that in the system discussed in this paper, the presence of effects of band gap edges causes the density of states of the electromagnetic fields is increased, the group speed of the electromagnetic waves is decreased (as a result, the interaction time is increased) and local field is boosted. As a result of these three factors, the nonlinear optical interaction is effectively strengthened.

(Invited) Electroluminescent Hyperbolic Cooling of Graphene Field Effect Transistors

Heat management is critical for the performance of most modern electronic devices. It was recently proposed that radiative heat transfer - which is usually negligible in the solid state - could be increased in hyperbolic metamaterials, i.e., materials having a hyperbolic electromagnetic dispersion relation. [1] However, artificial metamaterials can be difficult to fabricate and integrate.Fortunately, most of Van der Waals materials are natural hyperbolic metamaterials. Indeed, due to their anisotropic layered structure, the in-plane and out-of-plane optical phonon energy splitting results in a hyperbolic dispersion of light in the Resstrahlen bands. As a consequence, in these materials, the strong light-matter coupling can give rise to a 102-105 increase in the e.m. local density of states, resulting in a dramatic enhancement of the radiative heat transfer. Moreover, the radiative character of heat exchange results in a propagative heat transport via hyperbolic phonon-polariton (HPhP) modes on micrometric scales.We have studied heat transfer in graphene on hexagonal boron nitride: a natural 2D hyperbolic material. In our devices, graphene is used as a versatile heat source in the near field of a hyperbolic material, and as a sensitive noise thermometer. [2] Using mono-, bi- and trilayer graphene, we demonstrate a strong increase of the electron gas cooling resulting in a large temperature drop when the emission of HPhP sets in. This process shares many analogies with electroluminescence, except that it involves near-field modes. We experimentally evidence that the case of graphene is unique, with cooling powers reaching few milliwatts per micron square [3], i.e., nine orders of magnitude larger than previously reported in the literature. Bibliography [1] S. Biehs, et al "Hyperbolic metamaterials as an analog of a blackbody in the near field." Phys. Rev. Lett. 109, 104301 (2012)[2] W. Yang, et al "A Graphene Zener–Klein Transistor Cooled by a Hyperbolic Substrate." Nat. Nanotech. 13, 47 (2018)[3] E. Baudin, et al "Hyperbolic Phonon Polariton Electroluminescence as an Electronic Cooling Pathway", Adv. Funct. Mat.1904783 (2019) Figure 1

Advanced Materials for Heat Energy Transfer, Conversion, Storage and Utilization

Advanced Materials for Heat Energy Transfer, Conversion, Storage and Utilization

Data analysis of two-dimensional ground penetration radar profiles in three-dimensional space to study of underground objects

The Ground Penetrating Radar can be effectively applied in ground surface exploration geophysics. Underground anomalies are shown in the ground penetratingradar slices in the form of signals having similarity in amplitude and phase. Typically, each point-scattering object can be seen as a form of hyperbola. During the Ground Penetrating Radar measurement in an urban environment, the data including information of high frequency electromagnetic waveforms were easily affected by civil noise (human activities, etc.). Shielded antennas could help to eliminate mostly the civil noise, but processing and analysis of the data were still difficult because of attenuation of electromagnetic waves and wave energy dispersion during their propagation in the ground environment. Due to the field geometry condition, 2D profiles were conducted. In order to analyze and interpret data effectively, we processed each 2D profile separately and located all the 2D profiles into the 3D dimensional space for enhancing the ability of illuminating potential 3D anomalies and confirming the reliability of the data interpretation. We studied the data measured at an industrial company at Nhon Trach district, Dong Nai province, Vietnam. Results from the data analysis of ground penetration radar reflected the object in three-dimensional space.

ESTIMACIÓN DE LA CONSTANTE DIELÉCTRICA DEL SUELO MEDIANTEREFLECTOMETRÍA GNSS Y MÉTODO DE PATRÓN DE INTERFERENCIA

In this work we present an innovative and low-cost way to estimate the dielectric constant of real soils -which is relatedto soil moisture- using GPS satellite signal. The trajectory of the satellites was followed with an automated device, andwith an antenna type patch was measured the interference pattern generated by the direct GPS signal and that reflectedby the ground. To analyze the acquired signal, an electromagnetic dispersion model based on the method of smallperturbation was used, which may include stratifications in the underground and from which the dielectric constant thatbest fits the measurements was obtained. These values were compared with the obteined using a sensor that measures thesoil dielectric constant textit in-situ. The comparisons shows that the method based on the interference pattern providessatisfactory results to estimate the dielectric constant of real bare soils. Finally, proposals are outlined to improve theresults obtained in this work.

Hyperbolic Phonon Polariton Electroluminescence as an Electronic Cooling Pathway

AbstractEngineering of the cooling mechanism is of primary importance for the development of nanoelectronics. While radiation cooling is rather inefficient in current electronic devices, the strong anisotropy of 2D materials allows for enhanced efficiency because their hyperbolic electromagnetic dispersion near phonon resonances allows them to sustain much larger (≈105) number of radiating channels. In this review, radiation cooling in 2D materials is addressed. The hyperbolic dispersion of electromagnetic waves is presented, and how the spontaneous fluctuations in current in a 2D electronic channel can radiate thermal energy in its hyperbolic surrounding medium is described. Both the regime of thermal current fluctuations and out‐of‐equilibrium current fluctuations can be described within the same framework leading to superPlanckian thermal emission and electroluminescent cooling. A recent experimental investigation on graphene‐on‐hBN transistors using electronic noise thermometry is discussed. In high mobility semimetal‐like graphene at large bias, a steady‐state out‐of‐equilibrium situation is caused by Zener tunneling of electrons, opening a route for electroluminescence of hyperbolic electromagnetic modes. Electroluminescent cooling is particularly prominent once the Zener tunneling regime is reached: observed cooling powers are nine orders of magnitude larger than in conventional LEDs.

Hydrocarbon saturation in a Lower-Paleozoic organic-rich shale gas formation based on Markov-chain Monte Carlo stochastic inversion of broadband electromagnetic dispersion logs

An organic-rich shale gas formation generally exhibits high clay content, high total organic carbon (TOC), low porosity, high tortuosity, and the presence of conductive pyrite that adversely affect the well-log-derived hydrocarbon saturation estimations. In the presence of such petrophysical conditions, log-derived hydrocarbon saturation estimates obtained from multi-mineral analysis solver and various subsurface electromagnetic (EM) logs, such as induction resistivity log, dielectric permittivity log, or dielectric dispersion logs, are not consistent and can vary up to 0.5 saturation unit for a single depth. In addition, hydrocarbon saturation estimates derived from EM logs using conventional saturation models tend to break down in organic-rich shale gas formation because of the unaccounted interfacial polarization effects of clays and conductive minerals. Several of the above-mentioned issues can be addressed by processing downhole broadband EM dispersion logs using a mechanistic clay-pyrite interfacial-polarization model to accurately estimate hydrocarbon saturation in organic-rich shale gas formations.EM induction resistivity, logging while drilling (LWD) propagation, and dielectric dispersion logging tools were jointly deployed in a well drilled in an organic-rich shale gas formation to acquire continuous broadband EM dispersion measurements at 7 EM-log-acquisition frequencies for a total depth of 1500 m in the well. This was the first ever acquisition of broadband EM dispersion logs, comprising relative permittivity and conductivity measured at the 7 EM-log-acquisition frequencies. In this paper, a new Markov-chain Monte-Carlo-based (MCMC) stochastic inversion scheme coupled with a clay-pyrite interfacial-polarization (IP) model is used to process the EM broadband dispersion logs, and simultaneously estimate hydrocarbon saturation, connate water conductivity, and surface conductance of clay in the shale gas formation. The proposed Markov-chain Monte Carlo-based stochastic inversion scheme is robust to noise and exhibits fast convergence. The estimated hydrocarbon saturation is also compared against those derived from resistivity log, dielectric dispersion logs, and multi-mineral analysis solver. The estimated hydrocarbon saturation, connate water conductivity, and surface conductance of clay in two specific intervals of the shale gas formation are in the ranges of 0.2–0.9, 0.1 S/m–0.25 S/m, and 1 × 10−7 S–1 × 10−6 S, respectively.

Catenary Electromagnetics for Ultra-Broadband Lightweight Absorbers and Large-Scale Flat Antennas.

Catenary functions are exciting and fundamental building blocks in constructing various kinds of waves in subwavelength structures. Here, a simple yet powerful approach inspired by catenary optics is proposed to realize efficient manipulation of electromagnetic waves in terms of both amplitude and phase. By properly engineering the catenary electromagnetic fields and frequency dispersion, lightweight metafilm‐based broadband absorbers with polarization‐independent bandwidth covering 0.65–6.2 GHz are experimentally achieved, and the bandwidth is further broadened to 0.9–40 GHz. With the same approach, a large‐scale flat antenna based on generalized reflection is demonstrated in the satellite communication system. To enable the batch manufacturing, a flexible substrate–based microfabrication process is developed with a minimum feature size of down to sub‐micrometer and total size up to almost 1 m. These results may provide important guidance for the design of metasurface‐based devices.

Disorder Effect on the Transmission of Second Harmonic Waves in One-Dimensional Periodically Poled LiTaO<sub>3</sub>

One of the methods for calculating electromagnetic wave dispersion in multi-layer structures is the transfer matrix method. In this paper, we use the transfer matrix method for second harmonic generation in a nonlinear multilayer structure. The nonlinear photonic crystals investigated in this paper are as one-dimensional multi-layered structures including ferroelectric materials such as LiTaO3. Our goal is to investigate the effect of the disorder on the transmission spectrum of electromagnetic waves. Our results showed that positional disorder has different effects on the transmitting band and the gap band. The disorder in the transmitting band reduces the transmission coefficient of the waves and increases the transmission coefficient of the waves in the gap band. Such work has not yet been done on nonlinear photonic crystals producing the second harmonic.

Electromagnetic linear dispersion relation for plasma with a drift across magnetic field revisited

A current across the magnetic field is formed in various situations in plasma. The relative drift between ions and electrons due to the cross-field current becomes a source of various microscopic instabilities. A fully electromagnetic and kinetic linear dispersion relation for plasma with a drift across magnetic field is derived by assuming a uniform background plasma. The dielectric permittivity tensor for shifted Maxwellian velocity distributions is also presented. Linear dispersion relations obtained by using the new dielectric permittivity tensor were confirmed by comparison with the previous studies and with particle-in-cell simulation results.

Foreword: Special Section on Addressing Signal and Power Integrity in Future Generation Systems—Part I: Technology and Design Considerations

Ensuring signal and power integrity (SPI) is a primary concern for the electronic packaging community. The continuous increase of operating frequencies, combined with more and more aggressive miniaturization and integration strategies, poses tremendous challenges to designers. Every transistor must receive power with reduced noise, and all signals must be received properly, despite the plethora of signal and power degradation effects due to crosstalk and electromagnetic interaction, losses, and dispersion due to material nonidealities, reflections due to mismatches, and discontinuities, just to name a few. Proper handling of such effects requires precise characterization through modeling, suitable design strategies to minimize them, and the technological ability to realize the design.

Electromagnetic dispersion characteristics of a high energy electron beam guided with an ion channel

Taking self-fields into consideration, dispersion properties of two types of electromagnetic modes for a high energy electron beam guided with an ion channel are investigated by using the linear perturbation theory. The dependences of the dispersion frequencies of electromagnetic waves on the electron beam radius, betatron frequency and boundary current are revealed. It is found that the electron beam radius and betatron frequency have different influences on the electromagnetic waves dispersion behavior by compared with the previous works. As the boundary current is taken into account, the TM modes will have two branches and a low-frequency branch emerged as the new branch in strong ion channel case. This new branch has similar dispersion behavior to the betatron modes. For TE modes, there are two branches and they have different dispersion behaviors in strong ion channel case. However, in weak ion channel case, the dispersion behaviors for both of the low frequency and high frequency branches are similar.

Electromagnetic Waves Dispersion and Interaction of an Annular Beam-Ion Channel System in Plasma Waveguide

A linear theory for the electromagnetic properties and interactions of an annular beam-ion channel system in plasma waveguide is presented. The dispersion relations for two families of propagating modes, including the electrostatic and transverse magnetic modes, are derived. The dependencies of the dispersion behavior and interaction for different wave modes on the thickness of the annular beam and betatron oscillation frequency are studied in detail by numerical calculations. The results show that the inner and outer radii of the beam have different influences on propagation properties of the electrostatic and electromagnetic modes with different betatron oscillation parameters. In the weak ion channel situation, the two types of electrostatic waves, that is, space charge and betatron modes, have no interaction with the transverse magnetic modes. However, in the strong ion channel situation, the transverse magnetic modes will have two branches and a low frequency mode emerged as the new branch. In this case, compared with the solid beam case, the betatron modes not only can interact with the high frequency branch at small wavenumber but also can interact with the low frequency branch at large wavenumber.

Electromagnetic dispersion and sensitivity characteristics of carbonate reservoirs

The need to develop a new measurement method for the identification of favorable hydrocarbon-producing zones in carbonate reservoirs is of great importance due to their complex pore structure and lithology. We have evaluated fundamental experimental data acquired from carbonate formation samples in a buried-hill reservoir to demonstrate the magnitude of the complex resistivity (CR) dispersion effect in oil-saturated carbonate rocks and the possibility of identifying hydrocarbon-bearing carbonate sections. Our experimental data set included CR measurements on four carbonate core samples with various degrees of oil saturation, and at each saturation level, CR measurements were acquired in a frequency range between 10 Hz and 100 kHz. The experimental data indicated that the intensity of the CR dispersion effect increased with oil saturation above a specific critical excitation frequency. The experimental spectra of the carbonate samples were fitted with the Debye model and the Cole-Cole model (CCM), which can be used to interpret the dispersion effect over a wide frequency range. Based on the experimental data and the inverted CCM parameters, a sensitivity study was carried out with the crosswell frequency-domain electromagnetic (EM) modeling. Multifrequency EM data were acquired directly by calculating the Maxwell equation with the CR. Our experimental data and forward modeling results indicated that measurement of induced polarization and EM coupling effects can be an effective means for identifying carbonate hydrocarbon reservoirs and for quantitatively evaluating the effect of formation saturation on favorable conditions.

Use of electromagnetic two-layer wave-guided propagation in the GPR frequency range to characterize water transfer in concrete

The objective of this paper is to adapt a recent innovative technique for extracting and exploiting the Electromagnetic (EM) waveguide dispersion of civil engineering materials by means of GPR, and allowing to monitor the water ingress front during the absorption process for various concrete mixes. This technique is based on an inversion procedure that applies the Electromagnetic Waveguide Model (WGM) to invert phase velocity dispersion curves in their modal form. A Parallel homogenization model, derived from the Lichtenecker-Rother equation, has been employed to extend the waveguide model from a one-layer to a two-layer medium. The WGM outputs are then used to estimate the geometric parameters of the propagation medium and offer a primary application to water transfer monitoring in concrete through capillarity effects. The initial WGM validation is carried out on FDTD-simulated propagation signals, while the second validation relies on GPR data acquired from homogeneous materials. Then, a broad-based experimental study is conducted for the purpose of correlating electromagnetic waveguide dispersion parameters with both the geometric and hydric characteristics of various concrete mixes. Results obtained using the two-layer WGM serve to monitor the water ingress front during an absorption process. These results are then compared to the moisture gradients generated on cores using gammadensimetry, which is set as the reference. This procedure yields a number of trends, which in turn provide key information on the conditioning state of the studied concretes.

Enhancing absorption in coated semiconductor nanowire/nanorod core–shell arrays using active host matrices

In the present work, we investigated theoretically and experimentally the interaction of radiation field phenomena interacting with arrays of nanowire/nanorod core–shell embedded in active host matrices. The optical properties of composites are explored including the case when the absorption of propagating wave by dissipative component is completely compensated by amplification in active (lasing) medium. On the basis of more elaborated modeling approach and extended effective medium theory, the effective polarizability and the refractive index of electromagnetic mode dispersion of the core–shell nanowire arrays are derived. ZnS(shell)-coated by sulphidation process on ZnO(shell) nanorod arrays grown on (100) silicon substrate by chemical bath deposition (CBD) has been used for theoretical comparison. Compared with the bare ZnO nanorods, ZnS-coated core/shell nanorods exhibit a strongly reduced ultraviolet (UV) emission and a dramatically enhanced deep level (DL) emission. Obviously, the UV and DL emission peaks are attributed to the emissions of ZnO nanorods within ZnO/ZnS core/shell nanorods. The reduction of UV emission after ZnS coating seems to agree with the charge separation mechanism of type-II band alignment that holes transfer from the core to shell, which would quench the UV emission to a certain extent. Our theoretical calculations and numerical simulation demonstrate that the use of active host (amplifying) medium to compensate absorption at metallic inclusions. Moreover the core–shell nanorod/nanowire arrays create the opportunity for broad band absorption and light harvesting applications.