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A method for separating clean plates of epicuticular wax has been proposed. The use of water, which can penetrate deeply into wax structures under the influence of van der Waals forces and expand upon freezing, allows to quickly obtain uncontaminated wax plates with a native structure without any third-party chemical impurities. Using scanning electron microscopy, images of blue spruce (Picea pungens Engelm.) needle wax were obtained. Its morphological and structural characteristics have been determined. A distinctive feature is the presence of wax nanotubules with a characteristic diameter of ~150 nm and a length of 3–5 μm. Nanotubes lie on top of each other in stacks, forming a one-dimensional long-period lattice. Microscopic observations of the wax were made in reflected and transmitted light. It has been shown that the coating of blue spruce needles consists of microparticles of wax with a structural color. In a wide spectral range, individual particles change color from blue to red, as a result, large conglomerates of particles are white. Fluorescence spectra of needles with native wax cover and the same needles after wax removal were obtained. When comparing the width of fluorescence lines at half-height of blue spruce needles with and without wax, the influence of the wax layer on the lifetime of excited electrons in photosystem II was revealed, thereby establishing a connection between the wax cover and the process of photosynthesis. Using the matrix transfer method, transmission spectra were calculated for a lattice similar to a waxy structure, a chloroplast, and a combination of a waxy structure with a chloroplast. In the latter version, the long-wave zone of selective reflection is much wider than in individual cases. When examining a structure containing a chloroplast and epicuticular wax, there is a slight splitting of the stop zone, as if there were a defect, which contributes to a high concentration of energy at the site of splitting. Due to an increase in energy concentration, the density of photonic states at the corresponding wavelengths increases. This effect is important for photosynthesis because, according to Fermi’s golden rule, the rate of reaction is proportional to the density of photonic states. The calculation results are in good agreement with the experimental spectra.

We propose an improved structure of an optical biosensor based on a photonic crystal with a defect layer, which can detect the concentration of organic contaminants in water by defect mode shift. We investigated 4 types of defective photonic crystals with different arrangements of layers inside the perfect photonic crystals and their impact on the performance of the sensor. The sensitivity and amplitude of defect mode were examined as a function of defect layer thickness. Also, the peculiarities of edge modes in the presence of defect layer were investigated. Finally, we obtained a characteristic equation to determine the wavelengths of defect modes for an arbitrary 1D photonic crystal with an isotropic defect inside.

Subject and Purpose. Special features of all-dielectric electromagnetic analogues of topological insulators (TI) in the microwave range are considered, aiming at studying the influence of geometrical and constitutive parameters of TI elements on the dispersion properties of topological insulators based on a two-dimensional double-periodic array of dielectric elements. Methods and Methodology. The evaluation of dispersion properties and electromagnetic field spatial distribution patterns for topological insulators is performed using numerical simulation programs. Results. The electromagnetic analogue of a topological insulator based on a double-periodic array of elliptical quartz cylinders has been considered. By numerical simulation, it has been demonstrated that the electromagnetic properties of the structure are controllable by changing the quartz uniaxial anisotropy direction without any changes in other parameters. A combined topological insulator made up of two adjoining ones differing in shapes of their unit cells has been considered with the numerical demonstration that frequencies of surface states are controllable by choosing the quartz uniaxial anisotropy direction. It has been shown that it is at the interface of two different in shape unit cells that the electromagnetic field concentration at a surface state frequency takes place. Conclusion. A possibility has been demonstrated of controlling microwave electromagnetic properties of topological insulators by changing their geometric parameters and permittivity of the constituents. From a practical point of view, topological insulators can be used as components of microwave transmission lines and devices featuring very small propagation loss.

Background. Despite on the general trend towards decreasing the incidence of newly diagnosed active forms of tuberculosis, the situation with spreading of this disease in Russian Federation remains extremely tense. At the same time, the diagnosis is carried out according to the standard scheme, which takes about a month; another month takes test formulation for drug sensitivity. Thus, the development of new methods for diagnostics and typing of mycobacteria, as well as practice implementation of these developments is an urgent direction. Modern developments in the field of microfluidic technologies open up great opportunities in this direction. Aim. Development of a method for identification and typing of Mycobacterium tuberculosis using a label-free biosensor on surface waves in a one-dimensional photonic crystal (PC SM biosensor). Methods. Oligonucleotide probes were selected and synthesized as DNA targets for M. tuberculosis typing. The photonic crystal surface was modified with aqueous solutions of (3-aminopropyl)triethoxysilane, Leuconostoc mesenteroides dextrans and bovine serum albumin. Experiments were carried out using a PC SM biosensor. Results. Sequences of detecting oligonucleotide probes were selected for spoligotyping of M. tuberculosis on the PC SM biosensor. Modification of their 3'-ends was carried out in order to create extended single-stranded regions that are not subject to the formation of secondary structures and facilitate hybridization with a single-stranded DNA target. Several series of experimental modifications of the PC surface were carried out by using L. mesenteroides dextrans with different functional groups (including detection of the modification results real time) with simultaneous registration of the increment layer size and volume refractive index of the mixture, which excludes the use of a reference cell. Other experiments were carried out to detect the specific binding of biotinylated oligonucleotide probes to the modified PC surface. Conclusions. A technique for the design of probes was developed and a model system of oligonucleotides for the detection of single-stranded DNA using a PC biosensor was proposed. The developed technique of modification of the PC surface with dextrans from L. mesenteroides, which allows to increase the sensitivity of detection of oligonucleotides using the PC SM biosensor. This approach will further expand the panel of diagnostic probes, including identification of resistance markers.

Full-thickness skin grafts are used in reconstructive surgeries. Objectives Experimental study of the possibility of long-term preservation of viable skin grafts in severely impaired trophics at remote interaction with entities having stratiform periodic structure. Material and methods Full-thickness skin was excised from the rabbits' backside and dissected into explants sized 1.0 × 1.0 cm. The samples (n = 81) were divided into three groups and thermostated for 2 days at 37 °C at a various distance from the metal (aluminum) presented as a 20-layer package of smooth foil forming a stratiform periodic structure (SPS) (series I), chaotic layers of squeezed foil (series II) and a single-piece sheet (series III). Histological analysis was performed for the three series to evaluate the explants' viability after the thermostating. Results The highest survival estimates were seen in experimental explants of series I that interacted with the SPS of stratified foil layers. The wave nature of such remote interaction was suggested with delayed dystrophic and necrotic processes developing in the skin samples. Experimental samples of series III appeared to be less viable. The explant vitality in series II was sharply reduced due to rapidly spreading necrosis. Conclusion Skin explants were shown to retain viability for a longer time when interacting remotely with stratiform periodic structures in the absent trophics. These promising results can be practical for the development of wound dressings to improve survival of full-thickness skin transplantation in reconstruction of deep skin defects.

In the electric power industry of Russia and abroad, special attention is paid to the problem of an increase in the number of accidents caused by damage to high-voltage insulators in high-voltage equipment. An analysis of emergencies at substations and open switchgears [1- 2, 4] was carried out, which showed that in most cases the causes of damage to high-voltage insulators are natural aging in an applied electric field, overvoltage, and the presence of initial defects in the manufacture of high-voltage insulators. Based on this fact, we developed various methods of non-contact diagnostics of high-voltage insulators in order to identify defects at an early stage of their development. Particular attention was paid to the method of partial discharges because the characteristics of partial discharges provide information on the parameters of defects. The article describes a set of non-contact methods for remote diagnostics of high-voltage insulators; a two-channel method for remote diagnostics of the operating state of high-voltage insulators, based on the registration of partial discharges by electromagnetic and acoustic sensors; a device that allows visual inspection and the search for faulty high-voltage equipment; remote non-contact method for recording electric fields of high tension of industrial frequency, as well as their spatial orientation based on the electro-optical effect. We developed a mock-up of a portable diagnostic device for implementing research methods for high-voltage dielectric elements to diagnose their technical condition using the described complex of non-contact methods. The measuring device as part of a portable diagnostic device consists of a set of sensors for collecting diagnostic information detected by electromagnetic, acoustic and electro-optical sensors and a voltage phase signal applied to the studied highvoltage insulator. The simultaneous use of several sensors at once made it possible to increase the accuracy of localization of partial discharges in high-voltage insulators. Visualization of diagnostic results is possible at the control room in the form of amplitude-phase, frequencyphase and amplitude-frequency diagrams of the distribution of characteristics of partial discharges and on a portable device in the form of radiation intensity from the selected sensor. A portable diagnostic device made it possible in laboratory conditions to study electrophysical processes in various dielectric materials and products under the influence of strong alternating electric fields. A study was made of the features of defects on the rod and the terminal-terminal contact, a diagram of the electrophysical processes accompanying the emission of partial discharges was constructed, and the causes of their occurrence were established.

The aim of the work was to study the optical properties of the one-dimensional photonic crystals from ultrathin alternating layers of titanium and silicon oxides with different order of alternating layers to form defective half-wave layers in the bulk of the photonic crystal. The layer thicknesses were optimized by the dispersion of the refractive index and it was shown that for the formation of 16-layer photonic crystal structure without a half-wave layer with a photonic band gap in the UV region, it is necessary to use layers of titanium dioxide and silicon oxide with a thickness of 28.3 and 53.2 nm, respectively. The structure of the 26-layer photonic crystal with a thickness of 2130 nm with two non-equidistant half-wave layers forming resonant transmission bands in the photonic band gap with peaks at 550 and 601 nm is proposed. Due to the dispersion of the refractive index, the ratio of the thicknesses of TiO2:SiO2 layers varies from 1:1.88 in the case of a 16-layer structure with a photonic band gap in the UV region to 1:1.5 in the case of a 26-layer structure with a photonic band gap in the visible range . The effect of a photonic crystal structure without half-wave layers on the emission spectrum of a liquid crystal display manufactured using IPS technology has been demonstrated in order to reduce the intensity of the blue component to increase the safety of the user's vision. The using of the photonic crystals with two half-wave defective layers allows to achieve complete separation of the spectrum components, which can be used to modify the spectra of large liquid crystal panels, their manufacture using AMOLED technology is a very difficult technological task even for leaders in this field.

Calculations were performed using the transfer matrix of one-dimensional photonic crystals with low contrast and asymmetric structures of different periods. Such structures have been found in many plants. When joining two successively connected sublattices with different periods, an increase is observed in the amplitude of the electromagnetic field and the density of photon states inside the structure, and their change depends on the asymmetry of the thickness of the sublattices.

Guiding properties of an optical waveguide based on a layered metamaterial formed by layers of iron-yttrium garnet and aluminum-yttrium garnet, magnetized to saturation are considered. Dispersion equations for the waveguide TE and TM modes in the structure were obtained using the approximation of an effective medium and solving the boundary problem (electromagnetic method), and also by means of a 4×4 matrix method. Dispersion spectra of the propagation constant dependence on the cyclic frequency ω(β) for different types of structures are found, localization coefficients of the orthogonal modes in the guiding layer are also derived and their comparative analysis is carried out. The advantages of the approximate electromagnetic method are shown in comparison with the exact 4x4 matrix method. The results of the work can find an application in developing new integrated optical devices for optical signal processing based on layered metamaterials.

We consider the derivation of a dispersion relation of Bloch surface waves supported by interfaces between a semi-infinite one-dimensional photonic crystal and a homogeneous medium. From the derived dispersion relation, we obtain an explicit analytical expression that defines the relationship between the propagation constant and the thickness of the upper layer of the photonic crystal.

At present, the fast contactless identification of liquids enclosed into a container has a practical importance. The identification of liquids can be required, for example, at airports, in order to prevent the transport of illicit liquids in bottles. However, the complexity of applying contactless methods lies in the difficulties to take into account the influence of container characteristics. In this paper, a metamaterial based on two planar photonic crystals (PPC) has been applied for the experimental analysis of liquids in different containers. It was shown experimentally how the transmission coefficient spectrum of PPC varied with changing the characteristics of a container with a liquid. Namely, the influence of thickness and material of the container walls and the inclination angle of its axis relative to the metamaterial plane on the transmission coefficient has been studied. The reliable differing of concentration increments of edible salt and sugar in water was determined as 10 %. It is shown that an increase of the container walls thickness leads to a decrease of the reliability of the liquid identification in it. Thus, the influence of some container characteristics on the reliability of contactless identification of liquids by using PPC has been taken into account.

The purpose of this paper is an experimental investigation of the influence of properties of the silicon defect layer in a dielectric photonic crystal on the transmission peak spectral properties. The influence of the defect layer thickness on the defect mode frequency is shown. The possibility of changing characteristics of transmission peak by green laser illumination of the silicon layer is demonstrated and analyzed using a photonic crystal approach. It is experimentally found that illumination leads to a decrease of transmission coefficient value at the defect mode frequency, but does not lead to a change of this peak frequency. The non-equilibrium carriers concentration and their lifetime have been evaluated. The results of this paper can be used in manufacturing controllable circuits in millimeter waveband and the approach can be used in semiconductors manufacture as non-destructive control of semiconductors properties method.

We theoretically study eigenstates of electromagnetic field inside a one-dimensional photonic crystal containing a defect slab of layered superconductor. Basing on the transfer matrix formalism along with the electrodynamics of Josephson plasma, we obtain the dispersion relations describing the THz electromagnetic modes localized on defect. We consider both symmetric and antisymmetric configuration of defect in photonic crystal. The comparison of the dispersion spectra of the localized states for the layered-superconducting defect and the pure insulating defect reveals the features of the studied system.

Modification of the invariant imbedding method to describe the interaction of 3D electromagnetic field with "woodpile" photonic crystal of finite thickness is considered in this paper. This modification allows solving a problem of evanescent modes resonant amplification during numerical calculations for the first layer of photonic crystal. The mathematical model created in this work gives good agreement with physical experiment results.

An application of the invariant imbedding method to describe the interaction of 3D electromagnetic field with 2D photonic crystal of finite thickness, formed by a dielectric circular cylinder or square bars, is considered in this paper. Matrix coefficients of transmission and reflection for waves at different angles of incidence were calculated taking into account different types of polarization and non-coplanar diffraction.