Interaction Of Electromagnetic Waves Research Articles

Interaction of acoustic and electromagnetic waves for thermoacoustic imaging and vibration sensing

Acoustic wave and electromagnetic wave can interact and lead to rich physical phenomenon to be used for applications such as medical diagnosis, non-destructive material characterization, and remote sensing. In this talk, I will present our research studies on two ways acoustic and electromagnetic waves interact with each other: (1) When pulsed microwave is absorbed by tissue, thermoacoustic waves are generated through thermal expansion. We explored the sensing and processing of thermoacoustic waves generated by a pulsed microwave ablation antenna as a potential way for monitoring the ablation process in real time. (2) Electromagnetic waves such as Wi-Fi signals and light can be modulated by acoustic/mechanical vibrations in the environment. We developed non-contact vibration sensing systems based on such modulations, and also developed a metamaterial-based vibration amplification device that can enhance the vibration magnitude sensitivity over a broad range of vibration frequencies.

Simulating Electron Energy-Loss Spectroscopy and Cathodoluminescence for Particles in Arbitrary Host Medium Using the Discrete Dipole Approximation

Electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) are widely used experimental techniques for characterization of nanoparticles. The discrete dipole approximation (DDA) is a numerically exact method for simulating interaction of electromagnetic waves with particles of arbitrary shape and internal structure. In this work we extend the DDA to simulate EELS and CL for particles embedded into arbitrary (even absorbing) unbounded host medium. The latter includes the case of the dense medium, supporting the Cherenkov radiation of the electron, which has never been considered in EELS simulations before. We build a rigorous theoretical framework based on the volume-integral equation, final expressions from which are implemented in the open-source software package ADDA. This implementation agrees with both the Lorenz-Mie theory and the boundary-element method for spheres in vacuum and moderately dense host medium. And it successfully reproduces the published experiments for particles encapsulated in finite substrates. The latter is shown for both moderately dense and Cherenkov cases - a gold nanorod in $\text{SiO}_{\text{2}}$ and a silver sphere in $\text{SiN}_{\text{x}}$ respectively.

Extensive novel waves evolution of three-dimensional Yu–Toda–Sasa–Fukuyama equation compatible with plasma and electromagnetic applications

There is no doubt that the investigation of the interaction and propagation of plasma and electromagnetic waves play an important role in understanding these phenomena. The three-dimensional Yu–Toda–Sasa–Fukuyama equation (YTSFE) is a competent mathematical model of waves in plasma, electromagnetics, or fluids. An optimal system of infinitesimal symmetries is constructed to discover extensive and astonishingly exact solutions to the YTSFE. The outstanding solutions include periodic, polynomials, fractional, logarithmic, exponential, hyperbolic, exponential integral, Airy and complex functions. These solutions are significant because they help understand how plasma and electromagnetic applications work at different boundary or initial conditions.

Study of character of modulation instability in cyclotron resonance interaction of an electromagnetic wave with a counterpropagating rectilinear electron beam

In this paper, the interaction of a monochromatic electromagnetic wave with a counterpropagating electron beam moving in an axial magnetic field is considered. The purpose of this study is to investigate the conditions for occurrence of modulation instability (MI) in such a system and to determine at which parameters of the incident wave the MI is absolute or convective. Methods. Theoretical analysis of the MI character is carried out by studying the asymptotic form of unstable perturbations using the saddle-point analysis. The analytical results are verified by numerical simulations. Results. Theoretically, the boundary of change in the character of MI on the plane of input signal parameters (amplitude and detuning of the frequency from the cyclotron resonance) is determined. Numerical simulations confirm that as the signal frequency increases, the regime of self-modulation, which corresponds to the absolute MI, is replaced by the stationary single-frequency transmission corresponding to the convective MI. The numerical results coincide with the analytical ones for the system, which is matched at the end. The matching is implemented by smooth increasing of the guiding magnetic field in the region of electron beam injection. Conclusion. Determining the analytical conditions for the implementation of the absolute MI is of practical interest, since the emerging self-modulation can lead to the generation of trains of pulses with the spectrum in the form of frequency combs.

Surface plasmon-like properties of one-dimensional photonic crystal and its application in surface-enhanced fluorescence

The present work reports on the plasmon-like properties of one dimensional photonic crystal (1D PhC) as active material for surface-enhanced fluorescence application. 1D PhC was prepared through layer-by-layer deposition of spin coated Poly (methyl methacrylate) and vacuum deposited As2S3. The thicknesses of the alternating layers were tailored with Bragg’s condition for a quarter wave stack. The optical properties of the 1D PhC were characterized by UV-Vis-NIR spectrophotometry. The interaction of surface electromagnetic waves (SEW) supported by the photonic crystals with the localized surface plasmon waves spreading on the surface of very thin metallic films deposited on top of the 1D PhC was investigated. The efficiency of the surface-enhanced fluorescence was studied by using a 0.1 % w/v Cu (II)-phthalocyanine (CuPc) in Pluronic PE 6800 water solution. Two times enhancement of fluorescence signal of CuPc was observed in the case of Au overlayer on the surface of the 1D PhC.

Transport in Astrophysics: IV. Anomalous Redshift in the Solar System

The anomalous redshift on the sun’s limb and that measured by Pioneer-6 are interesting for the process of absorption of light and the spatial density of matter around the sun. Here we derive a 3D solution for the diffusion equation in the case of the steady state, which is then adopted as the density of the ionized matter around the sun. In order to deal with the observed light’s intensity, two integrals along the line of sight are evaluated. Alternatives to the Doppler shift have been considered as mechanisms: a thermal model, a plasma effect, the interaction of a low density electromagnetic wave with an electron and the interaction of light with a low density Fermi gas in standard QED. These four models are compared in the case of the Pioneer-6 signal.

Interaction of solitary electromagnetic waves in a 2D graphene superlattice

The mutual influence of solitons propagating along the axes of a two-dimensional graphene superlattice in mutually perpendicular directions has been studied. It is shown that due to the nonadditivity of the energy spectrum of the structure, the overlap region of solitons undergoes characteristic changes associated with the formation of pulses propagating along the fronts of interacting solitary waves.

Characterization of Transmission Lines in Microelectronic Circuits Using the ARTEMIS Solver

Modeling and characterization of electromagnetic wave interactions with microelectronic devices to derive network parameters has been a widely used practice in the electronic industry. However, as these devices become increasingly miniaturized with finer-scale geometric features, computational tools must make use of manycore/GPU architectures to efficiently resolve length and time scales of interest. This has been the focus of our open-source solver, ARTEMIS (Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver), which is performant on modern GPU-based supercomputing architectures while being amenable to additional physics coupling. This work demonstrates its use for characterizing network parameters of transmission lines using established techniques. A rigorous verification and validation of the workflow is carried out, followed by its application for analyzing a transmission line on a CMOS chip designed for a photon-detector application. Simulations are performed for millions of timesteps on state-of-the-art GPU resources to resolve nanoscale features at gigahertz frequencies. The network parameters are used to obtain phase delay and characteristic impedance that serve as inputs to SPICE models. The code is demonstrated to exhibit ideal weak scaling efficiency up to 1024 GPUs and 84% efficiency for 2048 GPUs, which underscores its use for network analysis of larger, more complex circuit devices in the future.

Interaction of two-frequency electromagnetic waves with anisotropic media over hydrocarbon accumulation

The article analyzes the interaction of two-frequency electromagnetic waves with anisotropic media over hydrocarbon accumulation. The behavior of the real component έ3 of the dielectric permittivity tensor is investigated. The choice of signal characteristics is based on the use of different electromagnetic wave emission sources with amplitude and frequency ratio coefficients in the modes of powerful low-frequency and high-frequency signals. The dielectric permittivity tensor component έ3 as a function of dielectric permittivity and frequency of sounding signals was analyzed. Sounding modes of anisotropic media over hydrocarbons are recommended to identify the medium over the deposits and increase the accuracy of determining the boundaries of hydrocarbon accumulation. The obtained results of the research can be used in prospecting geophysics.

Combating Coronavirus Using Resonant Electromagnetic Irradiation

The interaction of electromagnetic (EM) waves with the COVID-19 virus is studied to define the frequencies that cause maximum energy absorption by the virus and the power level needed to cause a lethal temperature rise. The full-wave EM simulator is used to model the virus and study the effects of its size and dielectric properties on the absorbed power across a wide range of frequencies. The results confirm potential resonance conditions, where specific frequencies produce maximum absorption and subsequent temperature rise that can destroy the virus. Furthermore, the study confirms that maximum power deposition in the virus occurs at specific wavelengths depending on its size. Also, the simulation is used to find the power required to destroy the virus and determine the total power required to destroy it in an oral activity, such as coughing, made by infected individuals. Furthermore, the study explained why irradiation by UV-C band is effective to decrease virus activity or even eradicate it.

Resonant absorption of light by a two-dimensional imperfect lattice of spherical particles.

The light absorption and scattering by an infinite two-dimensional array with an imperfect lattice of identical spherical particles is considered based on the statistical approach to a description of electromagnetic wave interaction with particulate media. Absorption resonances due to the coherent component of scattered light (zeroth order of diffraction) and resonances arising from the excitation of a flux of incoherently scattered light (higher diffraction orders) propagating at grazing angles to the array plane are studied. The dependence of absorption on the degree of positional ordering of particles is considered. It is shown that with an increase in ordering, the spatial coherence of the light flux along the array plane increases and the absorption resonance becomes more pronounced. Data are presented for silver wavelength-sized particles for s- and p-polarized incident waves. It is shown that at small angles of incidence, the first diffraction order can arise at the wavelength of zeroth-order resonance. In this case, the contributions to absorption created by the coherent and incoherent components of scattered light are summed up. The value of the absorption coefficient can be close to 0.95. A comparison with data for a partially ordered array is carried out.

Spin‐Controlled Reconfigurable Excitations of Spoof Surface Plasmon Polaritons by a Compact Structure

AbstractThe photonic spin Hall effect (SHE) arises from the spin–orbit interaction of lights and plays an important role in light–matter interactions. The phenomenon of spin‐momentum locking validates photonic SHE with unprecedented abilities in wave manipulation. Here, the directional coupling and spin‐momentum locking in spoof surface plasmon polaritons (SSPP) are demonstrated. The transverse spin angular momentum in SSPP is calculated using effective medium theory and the study shows the spin direction is inherently locked to the propagation direction, thus manifesting the spin–orbit interaction of electromagnetic (EM) waves. The spin‐momentum locking is further verified by projecting linearly and circularly polarized waves onto a scatterer‐SSPP structure. It is observed that the helicity of the incident EM wave governs the propagation direction of excited SSPP modes and the directional coupling originates from constructive and destructive interferences of two orthogonal modes. Reconfigurable transmissions of SSPPs are further demonstrated. The proposed design can find applications in reconfigurable sensors, antennas, and power dividers. This approach demonstrates the spin‐momentum locking in SSPPs and introduces new degrees of freedom to manipulate SSPPs by engineering the helicity and interference of EM waves.

Circuit Theory Based on New Concepts and Its Application to Quantum Theory

The Maxwell equations describe the interaction of electric and magnetic lines of force. However, Heaviside suggested that the interaction of electromagnetic waves is based on power and that their direction is perpendicular to the two lines of force owing to the roles of the Poynting vector. Therefore, the interaction of electromagnetic waves is analyzed by the expansion theorem derived by Heaviside. It is considered that the currently used z-transform and image parameter theory were developed from the expansion theorem. Heaviside also calculated the electromagnetic pulses (EMPs) for electrons, which give quantum mechanics a viewpoint different from the conventional concept.

Spherical Harmonic-Based Anisotropic Point Scatterer Models for Radar Applications Using Inverse Optimization

High-performance computing-based electromagnetic (EM) emulators are used to simulate real-time complex EM wave interactions between multiple radar targets, transmitters, and receivers. The radar cross section (RCS) of the radar targets are required to be stored as a table; however, the needed storage size increases dramatically with the angle and frequency sampling density. In this article, we present an innovative approach of constructing a concise spherical harmonic-based anisotropic point scatterer model that the emulators can use as part of the computations. The point scatterer model is constructed directly from the precomputed RCS data. First, we use only the monostatic RCS data and compute the spherical harmonic-based monostatic point scatterer model by solving a linear least-squares problem which has a group sparsity constraint. Then, we further compute the spherical harmonic-based bistatic point scatterer model using the full bistatic RCS data. The problem is formulated as a bilinear least-squares problem. The problem is solved using the normalized iterative algorithm, which linearly solves two parameters in a back and forth manner. The results show that the point scatterer model can effectively represent the bistatic RCS data of a radar target.

Electromagnetic waves in layered nanoresonator systems including bi-isotropic and metamaterial layers: analytical model and characteristic features of proper waves

The interaction of electromagnetic waves with multilayers of subwavelength thicknesses (nanoresonators) including the main layer made of a bi-isotropic material or metamaterial sandwiched between pairs of dielectric, epsilon-near-zero or metallic spacer layers has been modeled. The analytical model and numerical analysis are based on the exact and general solution of the electromagnetic boundary problem. The effects of birefringence, dichroism, chirality, nonreciprocity and new possibilities of their control and amplification, the conditions of excitation and features of proper waves inside of the bi-isotropic layer for various parameters of the nanoresonator geometry and components (in particular, metamaterials) and incident radiation are considered. It is shown that bi-isotropic effects in the one-layer chiral and nonreciprocal system can be significantly modified and amplified using the investigated nanoresonators.

Resonant energization of particles by radio AGN

Aims. A new mechanism of particle acceleration, based on the resonant interaction of a classical electromagnetic wave (EM) with a quantum wave (associated with a relativistic particle), is explored. Methods. In a model illustrative calculation, we study the fate of a Klein Gordon wave subjected to the intense radio frequency waves generated in the vicinity of an active galactic nuclei (AGN). In the framework of the paper, we examine a quantum wave associated with a relativistic particle, and it is shown that the group velocity of the wave approaches the speed of light, implying that the particles resonantly exchange energy with EM waves, eventually leading to acceleration of particles to very high energies. Results. For typical parameters of under accreting Eddington radio AGN, it is shown that the resonant energization could catapult particles to extreme energies ∼1016−20 eV.

Broadband 3-D shared aperture high isolation nine-element antenna array for on-demand millimeter-wave 5G applications

The paper presents the results of a novel 3-D shared aperture 3 × 3 matrix antenna-array for 26 GHz band 5 G wireless networks. Radiation elements constituting the array are hexagonal-shaped patches that are elevated above the common dielectric substrate by 3.35 mm and excited through a metallic rod of 0.4 mm diameter. The rod protrudes through the substrate of 0.8 mm thickness. It is shown that by isolating each radiating element in the array with a wall suppresses unwanted electromagnetic (EM) wave interactions, resulting in improvement in the antenna’s impedance matching and radiation characteristics. Moreover, the results show that by embedding hexagonal-shaped slots in the patches improve the antenna's gain and radiation efficiency performance. The subwavelength length slots in the patches essentially transform the radiating elements to exhibit metasurface characteristics when the array is illuminated by EM-waves. The proposed array structure has an average gain and radiation efficiency of 20 dBi and 93%, respectively, across 24.0–28.4 GHz. The isolation between its radiation elements is greater than 22 dB. Compared to the unslotted array the improvement in isolation between radiating elements is greater than 11 dB, and the gain and efficiency are better than 10.5 dBi, and 25%, respectively. The compact array has a fractional bandwidth of 16% and a form factor of 20×20×3.35 mm3.

Low Frequency Oscillations of Plasma Injected into an Open Magnetic Trap from an Independent Ultrahigh Frequency Source

Methods of plasma heating by electromagnetic waves, interaction of electro-magnetic waves with magnetoactive plasma, plasma turbulence and transport processes are investigated in the trap of the linear plasma device OMT2. An ultrahigh frequency (UHF) contactless method is used to fill the open magnetic trap by plasma. We propose a new method of open magnetic trap filling with plasma whereby plasma is injected in the trap along the magnetic field from an independent stationary UHF source. The source is located outside the trap and plasma formation in it takes place in the strongly nonuniform magnetic field, in the electron cyclotron resonance (ECR) regime by means of the UHF power. In this paper we study the efficiency of open magnetic trap filling by plasma and plasma low frequency (LF) oscillations in the trap.

PD-11 In depth analysis of label-free infrared (IR) imaging-based microsatellite instability (MSI) classification in early colon cancer (CC) on samples from the AIO ColoPredictPlus 2.0 (CPP) registry trial

MSI occurs in 15-20% of all early CC due to a deficient mismatch repair system and testing is now considered standard for all colon cancers as MSI is of prognostic and predictive value. Presently, protein analysis using immunohistochemistry targeting the mismatch repair proteins is most frequently used in routine clinical pathology with high sensitivity. Alternatively, fragment length analysis of microsatellite loci or next-generation sequencing can be used. All the techniques referred to are time and tissue consuming. We utilize label-free quantum cascade laser (QCL) based IR imaging combined with artificial intelligence (AI) approaches to test unstained tissue samples for MSI. IR imaging is an emerging microscopic technique based on the interaction of electromagnetic waves with the molecules within the tissue creating molecular fingerprints. To establish the methodological robustness of our approach, we analyzed samples from the multicentric prospective AIO ColoPredict Plus (CPP) 2.0 registry trial. IR imaging can analyze unstained paraffin-embedded tissue slides within an average of 30 min/slide. All tissue samples were obtained from the CPP registry trial. For development of the MSI/MSS classification model the cohort was split into a training, test, and validation set. The training set was utilized for the optimization of a modified VGG-16 convolutional neural network (CNN) with area under receiver operating characteristic (AUROC) and area under precision recall curve (AUPRC) evaluated on the test set as endpoints. The final classification model is validated on the validation set and in depth analyzed for sub-cohorts (BRAF, KRAS, UICC stage, grading). A cohort of 547 patients (training n=331 (43% MSI), test n=69 (43% MSI), validation n=147 (18% MSI)) was selected from CPP. Baseline characteristics including BRAF mutations, were balanced between training and test set, thus providing a balanced ground-truth for the training of the classifier. By contrast, the validation set (18% MSI) corresponds to the natural occurrence of MSI, showing a typically pattern for MSI and MSS with a higher proportion of female patients, more right-sided cases and more BRAF mutations for MSI-samples. The selected MSI/MSS classifier reached a validation AUROC of 0.90 (sensitivity 85%, specificity 84%) and AUPRC of 0.74. The AUROC of the sub-cohorts range between 0.78 and 0.99 (BRAF: 0.93 (wt), 0.78 (mt); KRAS: 0.84 (wt), 0.99 (mt); Grading: 0.93 (G2), 0.84 (G3); UICC Staging: 0.93 (II), 0.86 (III)). AI integrated IR imaging demonstrates a reliable classification performance for MSI/MSS with an AUROC of 0.90 (sensitivity 85%, specificity 84%) and robustness over sub-cohorts e.g., BRAF, KRAS, or staging. It further approaches the performance of the present gold standard immunohistochemistry. The combination of spatial and biochemical information encoded in the IR images allows CNNs to track changes on the molecular level. Additionally, this method requires fewer samples than other AI approaches and maintains intact tissue for further molecular analysis. Overall, this method has the potential to become an applicable diagnostic tool beyond the scope of known biomarkers for tumor-agnostic assessments.

Interaction of Ion Cyclotron Electromagnetic Wave with Energetic Particles in the Existence of Alternating Electric Field Using Ring Distribution

The elements that impact the dynamics and collaborations of waves and particles in the magnetosphere of planets have been considered here. Saturn’s internal magnetosphere is determined by substantiated instabilities and discovered to be an exceptional zone of wave activity. Interchanged instability is found to be one of the responsible events in view of temperature anisotropy and energization processes of magnetospheric species. The generated active ions alongside electrons that constitute the populations of highly magnetized planets like Saturn’s ring electron current are taken into consideration in the current framework. The previous and similar method of characteristics and the perturbed distribution function have been used to derive dispersion relation. In incorporating this investigation, the characteristics of electromagnetic ion cyclotron wave (EMIC) waves are determined by the composition of ions in plasmas through which the waves propagate. The effect of ring distribution illustrates non-monotonous description on growth rate (GR) depending upon plasma parameters picked out. Observations made by Cassini found appropriate for modern study, have been applied to the Kronian magnetosphere. Using Maxwellian ring distribution function of ions and detailed mathematical formulation, an expression for dispersion relation as well as GR and real frequency (RF) are evaluated. Analysis of plasma parameters shows that, proliferating EMIC waves are not developed much when propagation is parallelly aligned with magnetosphere as compared to waves propagating in oblique direction. GR for the oblique case, is influenced by temperature anisotropy as well as by alternating current (AC) frequency, whereas it is much affected only by AC frequency for parallel propagating waves.