Dispersion of Exciton Polaritons in Terbium Nitrate Hexahydrate

The dispersion relations of exciton polariton waves in terbium nitrate hexahydrate are determined based on the model of the interaction of electromagnetic waves with resonant electronic states of Tb³⁺ ions at the ⁵D₄–⁷F₆ transition. Frequencies of unitary polaritons characterized by refractive indices equal to unity are determined. It is shown that the group velocity of electromagnetic waves in the region of unitary polaritons is lower than the speed of light in vacuum by several orders of magnitude. A sharp increase in the efficiency of photoluminescence and Raman scattering is predicted in the case where the excitation radiation frequency approaches the unitary polaritons frequency.     

Propagation of electromagnetic waves in conducting graphene-like carbon nanoallotropes

Propagation of electromagnetic waves in graphene-like conducting carbon crystals with the (C)_4ν and (C)_6ν symmetries is studied. It is demonstrated that only TM waves can exist in such crystals. The comparative analysis of such waves in different structures is performed. It is shown that the structures under study are superior to classical graphene with respect to excitation of electromagnetic waves.     

Testing the variation of the fine structure constant with strongly lensed gravitational waves

The possible variation of the electromagnetic fine structure constant, αe, at cosmological scales has aroused great interest in recent years. Strongly lensed gravitational waves(GWs) and their electromagnetic counterparts could be used to test this variation. Under the assumption that the speed of a photon can be modified,whereas the speed of a GW is the same as predicted by general relativity, and they both propagate in a flat FriedmanRobertson-Walker universe, we investigated the difference in time delays of the images and derived the upper bound of the variation of αe. For a typical lensing system in the standard cosmological models, we obtained B cosθ 1.85×10~(-5),where B is the dipolar amplitude and θ is the angle between observation and the preferred direction. Our result is consistent with the most up-to-date observations on αe. In addition, the observations of strongly lensed GWs and their electromagnetic counterparts could be used to test which types of alternative theories of gravity can account for the variation of α_e.     

Reflecting electromagnetic waves from a surface of TbMnO3 with sinusoidal antiferromagnetic structure

A spectrum of coupled waves in TbMnO₃ with sinusoidal antiferromagnetic structure is investigated. Expressions for the activation frequencies are obtained, and temporal and spatial permittivity dispersions are considered. Frequency dependences for the reflectance of electromagnetic waves from the TbMnO₃ surface are calculated.     

The Results of Measurements of Features of Artificial Electromagnetic and Plasma Perturbations in the Outer Ionosphere of the Earth Using the DEMETER Satellite

The results of the DEMETER satellite mission for 2005–2010 are summarized. The characteristics of electromagnetic and plasma perturbations induced in the F₂ layer of the Earth’s ionosphere by the highpower HF radio waves from the SURA heating facility are analyzed.     

Some technical applications of ultrasonic location in gases

Radar systems cannot locate targets at close range because of the high velocity of propagation of electromagnetic waves; one solution is to use ultrasonic waves, which are much slower. This entails both investigation of environmental effects, and development of new transmitters and transducers. Successful results have been obtained in Doppler-shift speed measurements of cars and railway trucks, and pulse-echo distance measurements in coal mines and blast furnaces.     

Surface electromagnetic waves supported by nano conducting layers with inhomogeneities in the conductivity profile

Conducting interfaces and nano conducting layers can support surface electromagnetic waves. Uniform charge layers of non-zero thickness and their asymptotic behavior toward conducting interfaces of infinitely small thicknesses, where the thin charge layer is modeled via a surface conductivity σ _s , are already studied. Here, the possible effects of inhomogeneity in the conductivity profile of the thin conducting layers are investigated for the first time and a new approximate yet accurate enough analytical formulation for mode extraction in such structures is given. In order to rigorously analyze the structure and justify the proposed approximate formulation, the Galerkin’s method with Legendre polynomial basis functions is applied, i.e. the transverse electric field for the TE polarized surface waves and the transverse magnetic field for the TM polarized surface waves are each expanded in terms of Legendre polynomials and then each eigenmode; subjected to appropriate boundary conditions, is sought in the complete space spanned by Legendre basis functions. The proposed approximate solution is then proved to be accurate. In particular, sinusoidal fluctuations are introduced into formerly uniform conductivity profiles and it is numerically demonstrated that surface electromagnetic waves supported by nano conducting layers are not much sensitive to the very shape of conductivity profiles.     

Charge moving with the speed of light in Einstein-Maxwell theory

I give solutions of the Einstein-Maxwell equations describing charge moving with the speed of light,c. The motion generates plane-fronted electromagnetic and gravitational waves. Charges moving parallel to each other with speedc do not interact; nor do they interact with parallel light beams.     

Spatial distribution of the electromagnetic field near the surface of a dielectric medium

A boundary problem of linear classical optics is solved in which the behavior of the electromagnetic field near the surface of a dielectric medium is studied. It is shown that including the discrete structure of a medium into the analysis has the most substantial effect on the behavior of the electromagnetic field at distances smaller than 2a ₀, where a ₀ is the lattice constant. This fact makes it possible to obtain numerical estimates of the size of the region where the reflected and transmitted waves are formed.     

Double pulse heterothermal technology for the formation of domain structures in ferroelectrics

A technology for the formation of one- and two-dimensional structures by means of interfering (electromagnetic or acoustic) waves and a homogeneous electric field has been proposed. This technology has made it possible to retune the spatial period of the structure during its operation by varying the frequency of interfering waves and the angles of their incidence onto a crystal. It has been shown that the duration of the technological cycle slightly exceeds the domain switching time. The technology is applicable to crystals of LiNbO₃, KTiOPO₄ (with a high potassium content), and some others.     

Complete absorption of the transverse-magnetic waves by opaque layered systems

Absorptive layered systems which provide excitation of leaky surface electromagnetic waves are considered, and the conditions for complete absorption of incident transverse-magnetic modes are found. It is shown that such absorption can be achieved by proper choise of the angle of incidence and of the overlayer thickness. The infrared reflectance of Al coated with SiO₂ is calculated, examplifying the predicted effect.     

Dispersion of electromagnetic waves in the presence of magnetic monopoles of electron mass in a uniform magnetic field

The dispersion relation of electromagnetic waves in the presence of magnetic monopoles of electron mass in a uniform magnetic field is obtained. The waves of the frequencyω in the range ω_ϱi<Ω_i<ω<Ω _e <ω_ϱa are analysed. It is shown that the monopole charges lead to observable effects. Finally, the results are applied to a typical pulsar.     

Nonsymmetrical Electromagnetic Waves in Partially Plasma — Filled Waveguide

The dispersion of nonsymmetrical electromagnetic waves in waveguide, partially filled with plasma, is studied numerically and experimentally. An external d.c. coaxial magnetic field is applied to the waveguide. The dispersion equation of these waves is obtained, and it is solved numerically for the experimental conditions. Results are obtained, which show coupling of the waveguide HE_l1-modes with the family of the high-frequency plasma HE_ln-modes. The numerical dispersion curves are experimentally examined, and the influence of the magnetic field and the plasma density is studied.     

高频引力波对环形波导中电磁波的调制作用

讨论了垂直入射的、频率为ω_g的平面高频引力波对环形波导管中频率为ω_e的电磁波的调制作用．一般情况下，在波导管中与引力波传播方向垂直的对称平面附近，电磁波的能流密度会出现三种新的频率成分（2ω_e±ω_g）和ω_g．在ω_g》ω_e时，能流密度振幅的相对调制量与引力波的无量纲振幅h₀数量级相同．特别是当ω_g，ω_e和电磁波绕波导传播的绕行频率ω₀满足关系ω_g＝2ω_e》ω₀时，由于类似于共振的机制，能流密度会出现比h₀大几个数量级的振幅相对调制量．这个结果不会由于参数的微小改变而消失，这对于探测极微弱的引力辐射信号将是十分重要的 关键词：     

Radiation pressure

Formulae for the radiation pressure of electromagnetic and of sound waves are reviewed. The pressure on an obstacle in the path of the waves can be calculated from the momenta of the incident and scattered trains, and it is now well established that any train of waves of intensity J propagated with speed v has momentum J/v ² per unit volume. A general proof of this result is proposed, independent of the nature of the waves.     

Influence of a magnetic field on the mutual rectification of alternating currents induced by electromagnetic waves in graphene

The direct component of the electric current induced in graphene placed in a constant magnetic field has been found in the case where two electromagnetic waves with two mutually perpendicular planes of polarization are normally incident on the surface of the sample. It has been demonstrated that the direct component of the current along the direction of the electric field vector of the wave with the frequency ω₁ arises only when the ratio between the frequencies of the incident waves is ω₁/ω₂ = 2 or 1/2. In the latter case, the direct current component appears only in the presence of a magnetic field.     

Motion of a classical charged particle with spin in the external field of a plane electromagnetic wave

We obtain the solution to the equations of motion for a classical particle with spin, electric and magnetic charges, and electric and magnetic normal and anomalous moments, in the field of a plane electromagnetic wave. An explicit form of the solution is given for linearly polarized waves and monochromatic circularly polarized waves. The possibility is noted that due to the presence of the moments, the particle can be accelerated to speeds arbitrarily close to the speed of light.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 11, pp. 71–74, November, 1981.     

Electromagnetic wave modulation in hollow vanadium dioxide microcrystals

The optical properties of vanadium dioxide (VO₂) single crystals with a hollow rectangular inner channel are numerically simulated. In such microstructures, electromagnetic waves are shown to propagate in the form of waveguide modes, and the semiconductor-metal phase transition in VO₂ results in substantial modulation of the mode propagation constant. The propagation constants are calculated for TE, TM, and EH modes in the spectral range 0.8–1.3 μm.     

Nonlinear Evolution of a Gaussian Wave Perturbation in the Presence of a High Power Electromagnetic Plane Wave in the F Region Ionosphere

The interaction of a high power electromagnetic plane wave of uniform intensity with a weak electromagnetic Gaussian wave has been studies analytically. The two waves propagate vertically with almost the same frequency in the F region ionosphre. It is seen that the Gaussian wave acquires an oscillatory structure due to the nonlinear coupling of the strong plane wave and the weak Gaussian wave and the amplitude of these fluctuations grows with height. The growth, however, occurs only above a certain altitude z₀, which is determined by the plasma and wave parameters.     

Quantum Cherenkov radiation at the relative sliding of two transparent plates

Quantum Cherenkov radiation and quantum friction at the relative sliding of two transparent plates with the refractive index n have been studied in a fully relativistic theory. Radiation appears at velocities above the threshold value, v > v _c = 2nc/(n ² + 1). The contribution from s-polarized electromagnetic waves dominates near the threshold velocity. However, in the ultrarelativistic case (v → c), contributions from both polarizations are much larger than those in a nonrelativistic theory and a new contribution from the mixing of waves with different polarizations appears. The numerical results are supplemented by analytical calculations near the threshold velocity and the speed of light.