arXiv subjects

E. O. Kamenetskii

Publications and source records attributed to E. O. Kamenetskii.

At least 37 records · Page 2Linked to original sources

arXiv2014

Unidirectional magnetoelectric-field multiresonant tunneling

Unidirectional multi-resonant tunneling of the magneto-electric (ME)-field excitations through a sub wavelength (regarding the scales of regular electromagnetic radiation) vacuum or isotropic-dielectric regions has been observed in two-port microwave structures having a quasi-2D ferrite disk with magnetic-dipolar-mode (MDM) oscillations. The excitations manifest themselves as the Fano-resonance peaks in the scattering-matrix parameters at the stationary states of the MDM spectrum. The ME near-field excitations are quasi magnetostatic fields with non-zero helicity parameter. Topological-phase properties of ME fields are determined by edge chiral currents of MDM oscillations. We show that while for a given direction of a bias magnetic field (in other words, for a given direction of time), the ME-field excitations are considered as forward tunneling processes, in the opposite direction of a bias magnetic field (the opposite direction of time), there are backward tunneling processes. Unidirectional ME-field resonant tunneling is observed due to distinguishable topology of the forward and backward ME-field excitations. We establish a close connection between the Fano-resonance unidirectional tunneling and topology of ME fields in different microwave structures.

cond-mat.mes-hall↗

arXiv2013

Fano resonances of microwave structures with embedded magneto-dipolar quantum dots

Long range dipole-dipole correlation in a ferromagnetic sample can be treated in terms of collective excitations of the system as a whole. Ferrite samples with linear dimensions smaller than the dephasing length, but still much larger than the exchange-interaction scales are mesoscopic structures. Recently, it was shown that mesoscopic quasi-2D ferrite disks, distinguishing by multiresonance magneto-dipolar-mode (MDM) spectra, demonstrate unique properties of artificial atomic structures: energy eigenstates, eigen power-flow vortices and eigen helicity parameters. Because of these properties, MDMs in a ferrite disk enable the confinement of microwave radiation to subwavelength scales. In microwave structures with embedded MDM ferrite samples, one can observe quantized fields with topologically distinctive characteristics. The use of a quasi-2D ferrite-disk scatterer with internal MDM resonance spectra along the channel propagation direction could change the transmission dramatically. In this paper, we show that interaction of the MDM ferrite particle with its environment has a deep analogy with the Fano-resonance interference observed in natural and artificial atomic structures. We characterize the observed effect as Fano-resonance interference in MDM quantum dots.

physics.optics↗

arXiv2012

Topological-phase effects and path-dependent interference in microwave structures with magnetic-dipolar-mode ferrite particles

Different ways exist in optics to realize photons carrying nonzero orbital angular momentum. Such photons with rotating wave fronts are called twisted photons. In microwaves, twisted fields can be produced based on small ferrite particles with magnetic-dipolar-mode (MDM) oscillations. Recent studies showed strong localization of the electric and magnetic energies of microwave fields by MDM ferrite disks. For electromagnetic waves irradiating MDM disks, these small ferrite samples appear as singular subwavelength regions with time and space symmetry breakings. The fields scattered by a MDM disk are characterized by topologically distinctive power-flow vortices and helicity structures. In this paper we analyze twisted states of microwave fields scattered by MDM ferrite disks. We show that in a structure of the fields scattered by MDM particles, one can clearly distinguish rotating topological-phase dislocations. Specific long-distance topological properties of the fields are exhibited clearly in the effects of path-dependent interference with two coupled MDM particles. Such double-twisted scattering is characterized by topologically originated split-resonance states. Our studies of topological-phase effects and path-dependent interference in microwave structures with MDM ferrite particles are based on numerical analysis and recently developed analytical models. We present preliminary experimental results aimed to support basic statements of our studies.

physics.optics↗

arXiv2011

Microwave magnetoelectric fields

We show that in a source-free subwavelength region of microwave fields there can exist the field structures with local coupling between the time-varying electric and magnetic fields differing from the electric-magnetic coupling in regular-propagating free-space electromagnetic waves. To distinguish such field structures from regular electromagnetic (EM) field structures, we term them as magnetoelectric (ME) fields. We study a structure and conservation laws of microwave ME near fields. We show that there exist sources of microwave ME near fields - the ME particles. These particles are represented by small quasi-2D ferrite disks with the magnetic-dipolar-oscillation spectra. The near fields originated from such particles are characterized by topologically distinctive power-flow vortices, non-zero helicity, and a torsion degree of freedom. Our studies of the microwave ME near fields are combined in two successive papers. In this paper we give a theoretical background of properties of the electric and magnetic fields inside and outside of a ferrite particle with magnetic-dipolar-oscillation spectra resulting in appearance of the microwave ME near fields. Based on the obtained structures of the ME near fields, we discuss effects of so-called ME interactions observed in artificial electromagnetic materials. In the next paper, we represent numerical and experimental studies of the microwave ME near fields and their interactions with matter.

physics.optics↗

arXiv2011

Microwave near-field helicity and its role in the matter-field interaction

In the preceding paper, we have shown analytically that in a source-free subwavelength region of microwave fields there exist the field structures with local coupling between the time-varying electric and magnetic fields differing from the electric-magnetic coupling in regular free-space electromagnetic waves. As a source of such near fields, there is a small quasi-2D ferrite disk with the magnetic-dipolar-mode (MDM) spectra. The near fields originated from a MDM ferrite particle are characterized by topologically distinctive structures of power-flow vortices, non-zero helicity, and a torsion degree of freedom. In this paper, we present numerical and experimental studies on the microwave near-field helicity and its role in the matter-field interaction. We show that one can distinguish different microwave near-field-helicity parameters for different permittivities of dielectric samples loading a ferrite-disk sensor. We analyze a role of topological structures of the fields on the helicity properties. We demonstrate dependence of the MDM spectra and the near-field-helicity parameters from the enantiomeric properties of the loading samples.

physics.optics↗

arXiv2010

Coupled states of electromagnetic fields with magnetic-dipolar-mode vortices: MDM-vortex polaritons

Under the influence of the material environment, electromagnetic fields in the near-field regime exhibit quite different nature from those in the far-field free space. A coupled state of an electromagnetic field with an electric or magnetic dipole-carrying excitation is well known as a polariton. Such a state is the result of the mixing of a photon with an excitation of a material. The most discussed types of polaritons are phonon-polaritons, exciton-polaritons, and surface plasmon-polaritons. Recently, it was shown that in microwaves strong magnon-photon coupling can be achieved due to magnetic-dipolar-mode (MDM) vortices in small thin-film ferrite disks. These coupled states can be specified as MDM-vortex polaritons. In this paper we study properties of MDM-vortex polaritons. We show that MDM-vortex polaritons are characterized by helicity behaviors. For the observed frequency splits of MDM resonances there are different-type helicities. In the split-resonance states one has or localization, or cloaking of electromagnetic fields. We analyze numerically a variety of the field topological structures of MDM-vortex polaritons and give theoretical insights into the possible origin of such topologically distinctive states. The shown properties of MDM-vortex polaritons can be useful for realization of novel microwave metamaterial structures and near-field sensing applications.

physics.optics↗

arXiv2009

Space-time symmetry violation of the fields in quasi-2D ferrite particles with magnetic-dipolar-mode oscillations

In magnetic systems with reduced dimensionality, the effects of dipolar interactions allow the existence of long-range ordered phases. Long-range magnetic-dipolar interactions are at the heart of the explanation of many peculiar phenomena observed in nuclear magnetic resonance, ferromagnetic resonance, and Bose-Einstein-condensate structures. In this paper we show that magnetic-dipolar-modes (MDMs) in quasi-2D ferrite disks are characterized by symmetry breaking effects. Our analysis is based on postulates about a physical meaning of the magnetostatic-potential function as a complex scalar wave function, which presumes the long-range phase correlations. An important feature of the MDM oscillations in a ferrite disk concerns the fact that a structure with symmetric parameters and symmetric basic equations goes into eigenstates that are not space-time symmetric. The proper solutions are found based on an analysis of magnetostatic-wave propagation in a helical coordinate system. For a ferrite disk, we show that while a composition of two helical waves may acquire a geometrical phase over-running of during a period, every separate helical wave has a dynamical phase over-running of and so behaves as a double-valued function. We demonstrate that unique topological structures of the fields in a ferrite disk are intimately related to the symmetry breaking properties of MDM oscillations. The solutions give the MDM power-flow-density vortices with cores at the disk center and azimuthally running waves of magnetization. One can expect that the proposed models of long-range ordered phases and space-time violation properties of magnetic-dipolar interactions can be used in other magnetic structures, different from the ferromagnetic-resonance system with reduced dimensionality.

cond-mat.mtrl-sci↗

arXiv2009

Magnetic-dipolar-mode vortices and microwave subwavelength metamaterials

There has been a surge of interest in the subwavelength confinement of the electromagnetic fields. It is well known that in optics the subwavelength confinement can be obtained due to surface plasmon (quasielectrostatic) oscillations. In this paper we propose to realize the subwavelength confinement in microwaves due to dipolar-mode (quasimagnetostatic) magnon oscillations in ferrite particles. Our studies of interactions between microwave electromagnetic fields and small ferrite particles with magnetic-dipolar-mode (MDM) oscillations show strong localization of electromagnetic energy. MDM oscillations in a ferrite disk are origins of topological singularities resulting in Poynting-vector vortices and symmetry breakings of the microwave near fields. We show that new subwavelength microwave metamaterials can be realized based on a system of interacting MDM ferrite disks. The volume- and surface-wave propagation of electromagnetic signals in the proposed dense metamaterials will be characterized by topological phase variations. The MDM-particle-metamaterial concept opens a significantly new area of research. In particular, there is a perspective for creation of engineered electromagnetic fields with unique symmetry properties.

cond-mat.mtrl-sci↗

arXiv2008

Magnetoelectric Effect for Novel Microwave Device Applications

In a normally magnetized thin-film ferrite disk with magnetic-dipolar modes, one can observe magnetoelectric oscillations. Such magnetoelectric properties of an electrically small sample can be considered as very attractive phenomena in microwaves. In this paper we discuss the question on novel microwave device applications based on ferrite magnetoelectric particles.

cond-mat.mtrl-sci↗

arXiv2008

Spectral properties of interacting magnetoelectric particles

The linear magnetoelectric (ME) effect provides a special route for linking magnetic and electric properties. In microwaves, a local ME effect appears due to the dynamical symmetry breakings of magnetic-dipolar modes (MDMs) in a ferrite disk particle. The fact that for MDMs in a ferrite disk one has evident both classical and quantum-like attributes, puts special demands on the methods used for study of interacting ME particles. A proper model for coupled particles should be based on the spectral characteristics of MDM oscillations and an analysis of the overlap integrals for interacting eigen oscillating ME elements. In this paper, we present theoretical studies of spectral properties of literally coupled of MDM ME disks. We show that there exists the "exchange" mechanism of interaction between the particles, which is distinctive from the magnetostatic interaction between magnetic dipoles. The spectral method proposed in this paper may further the development of a theory of ME "molecules" and realization of local ME composites.

cond-mat.mtrl-sci↗

arXiv2008

Do the Tellegen particles really exist in electromagnetics?

In 1948 Tellegen suggested that an assembly of the lined up electric-magnetic dipole twins can construct a new type of an electromagnetic material. Till now, however, the problem of creation of the Tellegen medium is a subject of strong discussions. An elementary symmetry analysis makes questionable an idea of a simple combination of two (electric and magnetic) dipoles to realize local materials with the Tellegen particles as structural elements. In this paper we show that in his search of sources with local junctions of the electrical and magnetic properties one cannot rely on the induced parameters of small electromagnetic scatterers. No near-field electromagnetic structures and classical motion equations for point charges give a physical basis to realize sources with the local junction of the electrical and magnetic properties. We advance a hypothesis that local magnetoelectric (ME) particles should be the physical objects with eigenmode oscillation spectra and non-classical symmetry breaking effects. Our studies convincingly prove this assumption. We show that a quasi-2D ferrite disk with magnetic-dipolar-mode oscillations is characterized by unique symmetry features with topological phases resulting in appearance of the ME properties. The entire ferrite disk can be characterized as a combined system with eigen electric and magnetic moments. The fields near such a particle are distinguished by special symmetry properties.

cond-mat.mtrl-sci↗

arXiv2008

Magnetic-dipolar and electromagnetic vortices in quasi-2D ferrite disks

Magnetic-dipolar-mode (MDM) oscillations in a quasi-2D ferrite disk show unique dynamical symmetry properties resulting in appearance of topologically distinct structures. Based on the magnetostatic (MS) spectral problem solutions, in this paper we give an evidence for eigen MS power-flow-density vortices in a ferrite disk. Due to these circular eigen power flows, the MDMs are characterized by MS energy eigen states. It becomes evident that the reason of stability of the vortex configurations in saturated ferrite samples is completely different from the nature of stability in magnetically soft cylindrical dots. We found a clear correspondence between analytically derived MDM vortex states and numerically modeled electromagnetic vortices in quasi-2D ferrite disks.

cond-mat.mtrl-sci↗

arXiv2008

Magnetoelectric oscillations in quasi-2D ferrite disk particles

In this paper we show that magnetic-dipolar-mode (MDM) oscillations of a quasi-2D ferrite disk are characterized by unique symmetry features with topological phases resulting in appearance of the magnetoelectric (ME) properties. The entire ferrite disk can be characterized as a pair of two, electric and magnetic, coupled eigen moments. However, there is no a "glued pair" of two dipoles. An external electromagnetic field in the near-field region "views" such a ME particle, as a system with a normally oriented eigen electric moment and an in-plane rotating eigen magnetic dipole moment.

cond-mat.mtrl-sci↗

arXiv2008

Eigen power-flow-density vortices of magnetostatic modes in thin ferrite disks

In confined magnetically ordered structures one can observe vortices of magnetization and electromagnetic power flow vortices. There are topologically distinct and robust states. In this paper we show that in a normally magnetized quasi-2D ferrite disk there exist eigen power-flow-density vortices of magnetic-dipolar-mode oscillations. Because of such circular power flows, the oscillating modes are characterized by stable magnetostatic energy states and discrete angular moments of the wave fields. We show that the power-flow-density vortices of magnetostatic modes can be excited by electromagnetic fields of a microwave cavity. There is a clear correspondence between the power-flow-density vortex structures in a ferrite disk derived from an analytical solution of the magnetostatic-wave spectral problem and obtained by the numerical-simulation electromagnetic program.

cond-mat.mtrl-sci↗

arXiv2007

Electric self inductance of quasi-2D magnetic-dipolar-mode ferrite disks

An electric current flowing around a loop produces a magnetic field and hence a magnetic flux through the loop. The ratio of the magnetic flux to the electric current is called the (magnetic) self inductance. Can there be a dual situation with a magnetic current flowing around a loop and producing an electric field and hence an electric flux through the loop? Following the classical electrodynamics laws an answer to this question should be negative. Nevertheless special spectral properties of magnetic dipolar modes in a quasi-2D ferrite disk show there are the double-valued-function loop magnetic currents which may produce eigen electric fields and hence eigen electric fluxes through the loop. In this case one can definitely introduce the notion of the electric self inductance as the ratio of the electric flux to the magnetic current. In this paper we show experimentally that in the magnetic-dipolar-mode ferrite disks there exist eigen electric fluxes. These fluxes are very sensitive to permittivity parameters of materials abutting to the ferrite disk. Dielectric samples above a ferrite disk with a higher permittivity than air confine the electric field closely outside the ferrite, thereby changing the loop magnetic currents and thus transforming the magnetic-dipolar-mode oscillating spectrum.

cond-mat.mtrl-sci↗

arXiv2007

Eigen electric moments of magnetic-dipolar modes in quasi-2D ferrite disk particles

A property associated with a vortex structure becomes evident from an analysis of confinement phenomena of magnetic oscillations in a quasi-2D ferrite disk with a dominating role of magnetic-dipolar (non-exchange-interaction) spectra. The vortices are guaranteed by the chiral edge states of magnetic-dipolar modes which result in appearance of eigen electric moments oriented normally to the disk plane. Due to the eigen-electric-moment properties, a ferrite disk placed in a microwave cavity is strongly affected by the cavity RF electric field with a clear evidence for multi-resonance oscillations. For different cavity parameters, one may observe the "resonance absorption" and "resonance repulsion" behaviors.

cond-mat.mtrl-sci↗

arXiv2007

Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk

In microwaves, a TE-polarized rectangular-waveguide resonator with an inserted thin ferrite disk gives an example of a nonintegrable system. The interplay of reflection and transmission at the disk interfaces together with the material gyrotropy effect gives rise to whirlpool-like electromagnetic vortices in the proximity of the ferromagnetic resonance. Based on numerical simulation, we show that a character of microwave vortices in a cavity can be analyzed by means of consideration of equivalent magnetic currents. Maxwell equations allows introduction of a magnetic current as a source of the electromagnetic field. Specifically, we found that in such nonintegrable structures, magnetic gyrotropy and geometrical factors leads to the effect of symmetry breaking resulting in effective chiral magnetic currents and topological magnetic charges. As an intriguing fact, one can observe precessing behavior of the electric-dipole polarization inside a ferrite disk.

physics.class-ph↗

arXiv2007

Microwave whirlpools in a rectangular-waveguide cavity with a thin ferrite disk

We study a three dimensional system of a rectangular-waveguide resonator with an inserted thin ferrite disk. The interplay of reflection and transmission at the disk interfaces together with material gyrotropy effect, gives rise to a rich variety of wave phenomena. We analyze the wave propagation based on full Maxwell-equation numerical solutions of the problem. We show that the power-flow lines of the microwave-cavity field interacting with a ferrite disk, in the proximity of its ferromagnetic resonance, form whirlpool-like electromagnetic vortices. Such vortices are characterized by the dynamical symmetry breaking. The role of ohmic losses in waveguide walls and dielectric and magnetic losses in a disk is a subject of our investigations.

physics.class-ph↗