Artificial materials with negative magnetic and dielectric permittivity have unique electrodynamic properties that are not present in natural materials. We present the results of studying of the main magnetic LC resonance induced by a plane electromagnetic wave of GHz range in the linear structures of subwavelength dielectric ring elements with a high relative permittivity. The dielectric constant of the ring material (capacitor ceramics) is 160. Resonant scattering on the main magnetic mode and wave properties of linear structures consisting of subwavelength dielectric elements in the form of flat thin rings were studied. A single ring or ring structures were arranged in such a way that the vectors of the electric and magnetic fields of a plane incident electromagnetic wave were parallel to the plane of the ring, whereas the wave vector was perpendicular to the plane of the ring. Linear structures consisting of two or three rings were oriented along the magnetic vector of the incident wave. The magnetic field probe was placed on the line of the axis of symmetry of the ring and structures relative to the wave vector at the side of the structures most distant from the antenna. The spectra of transmitted radiation were measured during resonant excitation of magnetic fields in a system of dielectric rings in the near (distance — 2 mm) and remote (distance — 30 mm) zones from the ring. It is shown that in the near wave zone, splitting of the resonant frequency occurs due to mutual inductance and interaction of the rings. As the number of rings increases, the number of additional peaks also increases. A bandwidth of ~200 MHz with an amplitude 25 dB greater than the amplitude of the incident electromagnetic wave in the specified spectrum appears between the split levels. In the far zone, the transmitted radiation at the resonance frequency for a single ring practically does not change due to the splitting of this resonance frequency due to the interaction of the rings in the structure. The results obtained can be used in the development of new materials.

Possible plasma and photonic methods and devices for monitoring and preventing dangerous infections and human diseases are presented. In experiments with different types of atmospheric pressure discharges in different gases, the significant bactericidal effect was found. The prototype of device based on the method of absorption spectroscopy for detecting human diseases by biomarkers in the exhaled air has been proposed and tested. The importance of the plasma technology of deposition of coatings by magnetron sputtering for the creation of anti-covid masks and high-quality optics (mirrors) for photon monitoring devices is emphasized.

Resonance backscattering at the fundamental magnetic mode and the wave properties of linear structures consisting of subwave dielectric elements in the form of planar thin rings excited by the displacement currents of an incident microwave-range plane electromagnetic wave have been investigated. It is shown that the magnetic field at the main resonance frequency for a single ring is concentrated inside the ring and in the near-field zone, whereas for structures consisting of two or more rings the magnetic field is also registered in the far-field zone. The main magnetic resonances measured in the spectrum of electromagnetic fields for one and two planar rings coincide with the calculated resonance frequencies.

The influence of cross-dusting of silicon and metal targets simultaneously sputtered by argon ions on partial sputtering coefficients of targets materials components is studied to take this effect into account in the technology of gradient optical coating deposition. The effect has been numerically simulated as series of cascades of binary collisions of bombarding ions and recoil atoms with target atoms. Addition of metal atoms (Ti, V, Zr, Hf, Nb and Ta) to the Si target enhances the partial sputtering of Si atoms but addition of Si atoms to the metal targets decreases the partial sputtering of metals atoms. Also the coefficients of reflection (back scattering) of the bombarding argon ions from the targets with different additives have been calculated. It is possible that enhanced sputtering of Si atoms from the coatings with a “heavy” component by reflected neutralized ions would lead to dusting the “heavy” target by silicon.

Methods of preparation of single-crystal 4-N,N-dimethylamino-4′-N′-methyl stilbazolium tosylate (DAST) films with a thickness of several micrometers, designed for electro-optic modulation, have been analyzed. Thin-film single crystals have been obtained, the shape and absorption spectrum of which confirm their crystal structure of the “red” DAST crystal form. Homogeneous luminescence in the polarization-contrast regime indicates their single crystallinity and uniform orientation. These materials are designed for intracavity modulation of laser radiation.

Advantages of fabricating precision optical coatings by magnetron sputtering with a gas discharge powered from a medium-frequency current-variation supply unit are considered. The significance of selecting optimal characteristics and operating modes of the power supply sources of the magnetron sputtering system (MSS) for fabrication of high-quality optical coatings is justified. Using the developed magnetron sputtering facility that comprises a multimode power supply unit of the MSS, samples with thin TiO 2 films were fabricated at different recurrence frequencies f mag of the current pulses transmitted to the MSS and under other identical sputtering conditions. The samples were tested by laser ellipsometry, atomic force microscopy, X-ray diffractometry, and X-ray reflectometry. The influence of f mag on the functional properties of the TiO 2 films, namely, the refractive index, density, and roughness, is shown.

A physical-kinetic approach has been used for modeling of fast neutral atoms flow generation in the channel rays of abnormal glow discharge. The fast atoms are generated due to charge exchange of ions accelerated by voltage drop on the cathode layer of positive space charge. The limits of applicability of the created model and the range of operating parameters of the fast atom source are established for the Ar (gas) – Ta (cathode) pair. The work is directed towards implementation of the beam processing of dielectric optical nanostructured metamaterials with help of fast neutral atoms.                                                                               Â

Nanotechnology methods for obtaining 2D and 3D meta-materials are considered. The main attention is paid to the methods of forming submicron and nanometer structures using nanotechnology methods, first of all laser methods. It is shown that these technological methods, being planar and scalable, are promising for use in industrial optical production due to their potentially high productivity and low cost compared to many other methods of nanotechnology, in particular, with electronic lithography and processing with focused ion beams. Â

The basic methods of laser technology used to obtain 2D and 3D meta-materials are considered. The main attention is paid to the methods of forming submicron and nanometer structures using the two-photon polymerization effect and various types of laser interference lithography. It is shown that these technological methods, being planar and scalable, are promising for use in industrial optical production due to their potentially high productivity and low cost compared to many other methods of nanotechnology, in particular, with electronic lithography and processing with focused ion beams. Â

The results of calculation of the film thickness distribution of sputtered material deposited on a horizontal rotating disk substrate in a multi-cathode sputtering system with horizontal and inclined long plate targets are presented. The possibility of obtaining the high uniformity in the thickness distribution is shown, which makes it possible to recommend the similar system for use in precision optical technology.

Magnetron sputtering systems for the deposition of dielectric layers with a gradient variation in the refractive index are studied. A technology for the deposition of gradient coatings using a two-magnetron system operating in a mid-frequency pulsed ion sputtering mode is proposed. At a constant composition of the reaction gas medium and in an invariable magnetron operation mode, the required distribution profile of the refractive index is achieved owing to the substrate motion between magnetrons with targets made of different materials. The process is laser- and plasma-assisted and in situ optically controlled.

The technology of the middle frequency pulse reactive magnetron sputtering for fabrication of nanogradient optical coatings with smooth variation of refractive index was developed and studied. The technology is based on programmable motion of a substrate over two magnetrons with targets of different materials. The feature of the deposition process is a constant composition of reactive gas medium and an invariable magnetron operation mode. To realize this technology, an automatic computer-controlled sputtering system additionally comprising a gas discharge activator of reactive gas (oxygen) and an in situ optical monitor-spectrovisor has been built. The dielectric oxide-based nanogradient coatings of photon-barrier type were successfully fabricated. The obtained results confirm the high potential of the middle frequency pulse reactive magnetron sputtering of silicon and metal targets for fabrication of nanogradient dielectric optical coatings with excellent properties.

The non-locality of optical properties of gradient dielectric nanofilms, stipulated by smooth spatial distributions of refractive index, is shown to create the peculiar plasma-like dispersion of non-polar dielectric films, determined by the shapes and sizes of these distributions. Gradient all-dielectric nanostructures, characterized by the artificial heterogeneity-induced nonlocal dispersion and providing the broadband antireflection tunneling regime of energy transport in the visible and infrared ranges, are designed and tested. The wave energy flow in these structures is supported due to interference of evanescent and antievanescent modes formed by the non-Fresnel reflections of these modes on the discontinuities of gradient of refractive index on the boundaries of adjacent nanofilms. The transmittance spectra of these structures in the visible and infrared ranges, characterized by strong dispersion nearby the red edge of visible range, almost constant high transmittance in the near infrared range and weak dependence of tunneling energy flow upon the multilayer structure thickness, are calculated; the experimental verifications of these effects are presented. The perspectives to use the tunneling of light in gradient media for reconsideration of Hartman paradox are shown. Potential of periodical gradient all-dielectric nanostructures for optimized design of optical dispersive elements and broadband antireflection coatings for the visible and IR spectral range, respectively, is discussed.

The technology of fabrication of gradient dielectric nanofilms with the predesigned distribution of refractive index by means of magnetron sputtering of the nanofilm components on the movable substrate, based on the prescribed motion of substrate, is presented. The theoretical prediction of giant controllable heterogeneity-induced dispersion of gradient dielectric periodical nanostructures without free carriers is verified by the experimental measurements of their transmittance in visible and near infrared spectral ranges. The unusual transmittance spectra of these structures are distinguished by strong dispersion nearby the red edge of visible range and almost constant high transmittance in the near infrared range. Method of non-destroying control of gradient optical nanolayers, using the X-ray reflectometry of their density distribution, is developed, and the possibility of formation of nanocluster structures of these layers is shown. Potential of periodical gradient all-dielectric nanostructures for flexible design and fabrication of broadband antireflection coatings with sub-wavelength thicknesses is considered. (C)2014 Optical Society of America

Nowadays, much attention is paid on coatings with refractive index n distributed with nanometer variation within coatings. They are called as nanogradient coatings. The challenge is to develop a fabrication method, which could provide the desired thickness profile of n. Analysis of different approaches shows that the most appropriate is middle frequency pulse (MFP) magnetron discharge co-sputtering of several materials in a reactive gas atmosphere of constant composition at constant sputtering power of each component. The MFP technology is chosen because it provides the stable precisely controlled operation of magnetrons. The automated two-magnetrons installation for sputtering two materials (e.g. Si and Ti) has been developed. During deposition the location of several substrates varies in a plane above the magnetrons in accordance with the coating program. Each substrate rotates around its own axis and revolves around a common axis for all substrates, and the coordinate of the common axis is changed accordingly to the program. Two sputtered atom flows are mixed above the magnetrons and there is some distribution of the mixed atom flow composition on the substrate plane. The substrates intercept the atoms sputtered from both the magnetron targets, and thus, the instantaneous (current) composition of the deposited matter depends on the common axis coordinate. The duration of each common axis position is defined by the program, then we obtain the desired profile of n. The programs are able to provide different profiles of n (e.g. n varies from n(SiO 2 ) to n(TiO 2 ) with sine wave modulation) for fabrication of subwavelength photonic barriers, hyperwide antireflection coatings, phase correctors, filters and polarizers, gradient metacoatings [1] with excellent characteristics. [1] O.D. Volpian, A.I. Kuzmichev, Negative wave refraction. Introduction to physics and technology of electromagnetic metamaterials. Kiev, 2012.

Significant advantages of the magnetron sputtering method for producing complex high-quality optical coatings for laser devices are shown. Technology aspects of efficient fabrication of such coatings are considered. The capabilities of the developed automated technological and control equipment are described.

The complex optical and dielectric functions of the energy of an electromagnetic wave are calculated for a film of tantalum (V) oxide in the short-wavelength region, including the fundamental-absorption region. An additive combination of the Forouhi–Bloomer and Lorentz models is constructed to compute these functions. Versions of the Forouhi–Bloomer model with a dipole-transition matrix element that is independent of the wave energy are considered, along with a modified model. It is established that the modified model has an advantage when describing broad-band dielectric amorphous media. The optical band gap computed from the Forouhi–Bloomer and Lorentz models is compared with the value determined from the Tautz extrapolation.

Different technological approaches to fabrication of gradient metamaterials have been considered. Perspectives of applying the precisely controlled reactive pulse magnetron sputtering for obtaining gradient optical metamaterials/metacoatings are shown that is confirmed by obtaining excellent antireflection gradient coatings for visible and infrared light.

Propagation and tunneling of polarized light through gradient nanophotonic barriers, formed by continuous distributions of dielectric susceptibility epsilon(z) across the films, fabricated from dielectrics without free carriers, are considered. The decisive influence of giant artificial heterogeneity - induced non -local dispersion, both normal and abnormal, stipulated by the gradient and curvature of distribution epsilon(z), is shown to provide the polarization - dependent tunneling of radiation in any spectral range in need. New trends in technology of sputtering of gradient silicon films of controlled distribution of epsilon(z) on the substrate are developed, and the parameters of films, fabricated by means of these technologies, are measured. Special methods for polarimetric testing of gradient dielectric nanofilms, based on new exact analytical solutions of Maxwell equations for inclined incidence of polarized waves, are presented. New types of dispersive elements for photonic crystals, based on polarization effects in gradient dielectric nanofilms, including, e. g., mode selectors, miniaturized phase shifters and large angle polarizers, are discussed.

A theoretical investigation is made of the amplification in a transverse-flow CO2 laser. It is shown that the energy efficiency of a laser system with a multipass amplifier may be higher than the efficiency under oscillation conditions.