Nikolai N. Beletskii

In this paper, we theoretically investigate the dispersion properties of surface and bulk-surface electromagnetic waves propagating in a hybrid layered solid-state structure containing an isotropic plasmonic metasurface. This structure consists of a semi-infinite dielectric 1, an isotropic metasurface, a dielectric layer 2, and a semi-infinite plasma-like medium. We derive an exact analytical dispersion relation for the coupled electromagnetic modes and perform a comprehensive numerical analysis of it. Our analysis demonstrates how the metasurface conductivity, the dielectric layer thickness, and the semiconductor plasma frequency significantly influence the resonant interaction of the surface waves. It has been revealed that adding a plasma-like medium as a substrate leads to the emergence of hybrid surface waves and the possibility of bulk-surface waves. In fact, we found a significant difference between metal and semiconductor substrates. Indeed, to obtain exactly the same splitting value in a system with a metal substrate, a dielectric spacer approximately seven times thicker is required. This geometry difference makes semiconductors a much more practical choice for deep subwavelength miniaturization. The results provide a theoretical basis for the development and optimization of novel tunable waveguides, sensors, and slow-wave devices operating in the microwave and terahertz frequency ranges.

Subject and Purpose. In the context of growing anticipation of fundamentally new optical and radiophysical devices, the present study is concerned with the total electromagnetic wave tunneling through an asymmetric three-layer structure such that contains a conductive negative-permittivity layer. The aim of this work is to recognize how the asymmetry property of this three-layer structure acts on the effect of total wave tunneling with the frequency dispersion of the conductive negative-permittivity layer taken into account. Methods and Methodology. The frequency-dependent conditions of the total electromagnetic wave tunneling through an asymmetric three-layer structure are sought by numerical simulations. A universal approach based on the introduction of dimensionless frequencies and dimensionless layer thicknesses allows us to numerically investigate conditions of the total electromagnetic wave tunneling for any desired frequencies and geometric parameters of the asymmetric three-layer structure. Results. It has been shown that the asymmetry property of the three-layer structure can significantly change the total electromagnetic wave tunneling conditions. It has been demonstrated that parameters of the asymmetric three-layer structure can be selected in such a way as to modify the total electromagnetic wave tunneling conditions toward a desired practical application of the structure. It has been found that a proper choice of the parameters can minimize the action of the three-layer structure asymmetry on the electromagnetic wave tunneling effect. Conclusion. Asymmetric three-layer structures can be of use to effectively change conditions of the total electromagnetic wave tunneling in an effort to provide devices under development with desired characteristics.

The effect of reflectionless normal transit of electromagnetic waves through symmetric threelayered structures containing negative-permittivity layers excites considerable interest. It is stipulated by both an unusual nature of the effect and its unique technical applications. Moreover the electromagnetic-wave reflectionless transit effect has been investigated not enough and not all the peculiarities of the effect have been found and described yet. By now the reflectionless transit effect has been considered only for some concrete values of the permittivity and thickness of a symmetric three-layered structure. In this paper a more general approach based on entering dimensionless values of the thickness of the structure layers is used. This approach makes it possible to study the reflectionless transit effect irrelatively to some concrete wave band. It is shown that the presence of a negative-permittivity layer in a three-layered structure leads to a considerable change in the reflection spectrum of electromagnetic waves. It has been found that in the reflection spectrum of the electromagnetic waves there are wide regions of a weak reflection. The width of these regions can be controlled efficiently by matching a value of the negative permittivity of the middle layer in the three-layered structure. The influence of the energy losses in the middle layer of the three-layered structure on the reflection spectrum of the electromagnetic waves is studied. The obtained results are of great practical importance for developing new devices of electronics, photonics, and photovoltaics.

The effect of resonant interaction of plasma and defective electromagnetic waves in the defective photon crystal bordering on conducting medium is studied.

Currently much attention is paid to the investigation of electromagnetic properties of defective photon crystals. This is stipulated by both the occurrence of plasma and defective waves in such crystals and the zone nature of the wave spectrum. One of the most interesting electromagnetic properties of the defective photon crystals is the resonance interaction of plasma and defective waves. It is found that the resonant interaction is observed most distinctly in the second forbidden band of the photon crystal. In this connection the study of electromagnetic-wave properties in various types of defective photon crystals is a topical problem. This paper is devoted to the study of the effect of resonant interaction of plasma and defective electromagnetic waves in the onedimensional defective photon crystals bordering on a conducting medium subject to the condition that the defective layer is a plasma-like one. It is shown that the best conditions for observing the effect of resonant interaction of plasma and defective electromagnetic waves take place in the case when the defective photon crystal borders on the semiconductor plasma and the magnitude of the dielectric permeability of the defective layer is a positive value and has an intermediate value between the values of the dielectric permeability of two layers of a unit cell of the photon crystal. The obtained results are of great practical importance for developing new devices of microelectronics and photonics.

The study of the defective periodic layered structures bordering upon plasma-like media has attracted interest recently. This is due to the fact that in such structures there are the surface and bulk electromagnetic waves interacting resonantly. The effect of resonant interaction in defective periodic layered structures is not sufficiently studied. In the paper the resonant interaction of surface and bulk TM-electromagnetic waves in the one-dimensional defective dielectric periodic layered structure placed in a parallel-plate waveguide is investigated on the basis of a numerical solution of the dispersion equation. The dispersion and energy properties of the plasma and bulk modes are studied in accordance with the location of the defective layer in the periodic structure. It is shown that the peculiarities of the resonant interaction of the plasma and bulk waves essentially depend on the geometric configuration of the defective periodic layered structure. The results of our investigations expand considerably the knowledge about the nature of the resonant interaction of electromagnetic waves in defect periodic layered structures. They can be used in developing new models of radiophysical devices for the signal processing in microelectronics and photonics.