arXiv subjects

Stanislav I. Maslovski

Publications and source records attributed to Stanislav I. Maslovski.

12 recordsLinked to original sources

arXiv2018

Superabsorbing metamaterial wormhole: Physical modeling and wave interaction effects

Conjugate-impedance matched superabsorbers are metamaterial bodies whose effective absorption cross section greatly exceeds their physical dimension. Such objects are able to receive radiation when it is not directly incident on their surface. Here, we develop methods of physical modeling of such structures and investigate interactions of the superabsorbers with passing electromagnetic radiation. The particular superabsorbing structure under study is a wormhole comprised of meshes of loaded transmission lines. A theory of electromagnetic wave propagation and absorption in such metamaterial structures is developed. At the frequency of operation, the structure exhibits greatly enhanced absorption as compared to the black body-type absorber of the same size. Peculiar wave absorption effects such as trapping of nearby passing beams of electromagnetic radiation are demonstrated by numerical simulations. Possible modifications of the wormhole structure under the goal of optimizing absorption while minimizing complexity of the involved metamaterials are discussed. Conjugate-impedance matched superabsorbers may find applications as efficient harvesters of electromagnetic radiation, novel antennas, and sensors.

physics.class-ph↗

arXiv2018

Envelope Dyadic Green's Function for Uniaxial Metamaterials

Based on the dyadic Green's function (DGF) method, we present a formalism to study the propagation of electromagnetic fields with slowly varying amplitude (EMFSVA) in dispersive anisotropic media with two dyadic constitutive parameters, the dielectric permittivity and the magnetic permeability. We find the matrix elements of the envelope DGFs by applying the formalism for uniaxial anisotropic metamaterials. We present the relations for the velocity of the EMFSVA envelopes which agree with the known definition of the group velocity in dispersive media. We consider examples of propagation of the EMFSVA passing through active and passive media with the Lorentz and the Drude type dispersions, demonstrating beam focusing in hyperbolic media and superluminal propagation in media with inverted population. The results of this paper are applicable to the propagation of modulated electromagnetic fields and slowly varying amplitude fluctuations of such fields through dispersive and dissipative (or active) anisotropic metamaterials. The developed approach can be also used for the analysis of metamaterial-based waveguides, filters, and delay lines.

physics.app-ph↗

arXiv2018

Dynamics of slowly varying fields in bianisotropic media

A theoretical framework for the quasi-monochromatic electromagnetic (EM) processes such as excitation and propagation of long wave packets in dispersive, dissipative, bianisotropic media with weak and slow nonlinearity is developed. The time-dependent EM fields associated with such processes are expressed as products of two functions: the slowly varying complex amplitude (SVCA) and the quickly oscillating carrier. The material parameters are treated as operators acting on time-dependent EM fields. By expanding these operators in the Maxwell equations in a series with respect to a small time scale parameter a system of equations for the SVCAs of the EM fields in such media is formulated. In the linear case, the dynamic equations for the SVCAs that correspond to the transverse components of the electric and magnetic fields resemble the vector transmission line equations. The obtained system of equations is used to derive the dyadic Green functions for the SVCAs of the EM fields in bianisotropic media. This framework is applied for modeling propagation of partially coherent EM radiation in a material whose parameters may depend on the amount of the EM energy that has passed through it. The same framework can be used in studying propagation of modulated EM waves through a waveguiding system that includes bianisotropic metamaterial components.

physics.optics↗

arXiv2015

Overcoming black body radiation limit in free space: metamaterial superemitter

Here, we demonstrate that the power spectral density of thermal radiation at a specific wavelength produced by a body of finite dimensions set up in free space under a fixed temperature could be made theoretically arbitrary high, if one could realize double negative metamaterials with arbitrary small loss and arbitrary high absolute values of permittivity and permeability (at a given frequency). This result refutes the widespread belief that Planck's law itself sets a hard upper limit on the spectral density of power emitted by a finite macroscopic body whose size is much greater that the wavelength. Here we propose a physical realization of a metamaterial emitter whose spectral emissivity can be greater than that of the ideal black body under the same conditions. Due to the reciprocity between the heat emission and absorption processes such cooled down superemitter also acts as an optimal sink for the thermal radiation --- the "thermal black hole" --- which outperforms Kirchhoff-Planck's black body which can absorb only the rays directly incident on its surface. The results may open a possibility to realize narrowband super-Planckian thermal radiators and absorbers for future thermo-photovoltaic systems and other devices.

physics.optics↗

arXiv2015

Electromagnetic Energy Sink

The ideal black body fully absorbs all incident rays, that is, all propagating waves created by arbitrary sources. The known idealized realization of a black body is the perfectly matched layer (PML), widely used in numerical electromagnetics. However, ideal black bodies and PMLs do not interact with evanescent fields existing near any finite-size source, and the energy stored in these fields cannot be harvested. Here we introduce the concept of the ideal conjugate matched layer (CML), which fully absorbs energy of both propagating and evanescent fields of sources acting as an ideal sink for electromagnetic energy. Conjugate matched absorbers have exciting application potentials, as resonant attractors of electromagnetic energy into the absorber volume. We derive the conditions on the constitutive parameters of media which can serve as CML materials, numerically study the performance of planar and cylindrical CML and discuss possible realizations of such materials as metal-dielectric composites.

physics.optics↗

arXiv2014

Equivalent Circuit Analysis of Super-Planckian Emission into Far Field

Using our recently developed equivalent circuit model of radiative heat transfer we analyze the far-field thermal emission from bodies of constrained dimensions. We prove that the power radiated by a hypothetical metamaterial emitter which is conjugate matched with all the harmonics of the emitted field at a given wavelength can be infinitely higher than the power emitted by an ideal black body of the same radius. However, for optically large bodies, fulfilling the conjugate match conditions for higher-order harmonics is not a trivial task, which effectively limits the far-field radiated power by the well-known Planck law.

physics.optics↗

arXiv2012

Equivalent circuit model of radiative heat transfer

Here, we develop a theory of radiative heat transfer based on an equivalent electrical network representation for the hot material slabs in an arbitrary multilayered environment with arbitrary distribution of temperatures and electromagnetic properties among the layers. Our approach is fully equivalent to the known theories operating with the fluctuating current density, while being significantly simpler in analysis and applications. A practical example of the near-infrared heat transfer through the micron gap filled with an indefinite metamaterial is considered using the suggested method. The giant enhancement of the transferred heat compared to the case of the empty gap is shown.

physics.optics↗

arXiv2012

Finite-difference frequency-domain method for the extraction of effective parameters of metamaterials

Here, we report a numerical implementation of the nonlocal homogenization approach recently proposed in [M. Silveirinha, Phys. Rev. B 75, 115104 (2007)], using the finite difference frequency-domain method to discretize the Maxwell-Equations. We apply the developed formalism to characterize the nonlocal dielectric function of several structured materials formed by dielectric and metallic particles, and in particular, we extract the local permittivity, permeability and magnetoelectric coupling parameters when these are meaningful. It is shown that the finite differences frequency domain implementation of the homogenization method is stable and robust, yielding very accurate results.

cond-mat.mtrl-sci↗

arXiv2012

Equivalent circuit theory of radiative heat transfer on micro- and nanoscale

Here, we outline a theory of radiative heat transfer based on an equivalent electrical network representation for the hot material slabs in an arbitrary multilayered environment with arbitrary distribution of temperatures and electromagnetic properties among the layers. Our approach is fully equivalent to the known theories operating with the fluctuating current density, while being significantly simpler in analysis and applications.

physics.optics↗

arXiv2012

Radiation from elementary sources in a uniaxial wire medium

We investigate the radiation properties of two types of elementary sources embedded in a uniaxial wire medium: a short dipole parallel to the wires and a lumped voltage source connected across a gap in a generic metallic wire. It is demonstrated that the radiation pattern of these elementary sources have quite anomalous and unusual properties. Specifically, the radiation pattern of a short vertical dipole resembles that of an isotropic radiator close to the effective plasma frequency of the wire medium, whereas the radiation from the lumped voltage generator is characterized by an infinite directivity and a non-diffractive far-field distribution.

physics.class-ph↗

arXiv2011

Casimir repulsion in moving media

Casimir-Lifshitz interaction emerging from relative movement of layers in stratified dielectric media (e.g., non-uniformly moving fluids) is considered. It is shown that such movement may result in a repulsive Casimir-Lifshitz force exerted on the layers, with the simplest possible structure consisting of three adjacent layers of the same dielectric medium, where the middle one is stationary and the other two are sliding along a direction parallel to the interfaces of the layers.

cond-mat.mtrl-sci↗

arXiv2009

Non-local permittivity from a quasi-static model for a class of wire media

A simple quasi-static model applicable to a wide class of wire media is developed that explains strong non-locality in the dielectric response of wire media in clear physical terms of effective inductance and capacitance per unit length of a wire. The model is checked against known solutions and found to be in excellent agreement with the results obtained by much more sophisticated analytical and numerical methods. Special attention is given to suppression of the spatial dispersion effects in wire media.

cond-mat.mtrl-sci↗