This PDF file contains the front matter associated with SPIE Proceedings Volume 11066, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

A time delay (TD) model of difference-frequency generation in a cavity of a dual-wavelength semiconductor disk laser has been derived. By using the model, the steady state operation point, its stability and transient dynamics of an intracavity difference-frequency generator are analyzed. The identical quantities have been also studied with the help of the normal mode expansion (NME) model. Both models result in steadiness of the steady state points for all parameter’s values taken in the simulations. However, the dynamics behaves in rather different manners: the TD model results in the long-lived quasi-periodic relaxation oscillations, while the NME model leads to the fast aperiodic transition to the same steady state point. The time period of the relaxation oscillations equals to the cavity round-trip time.

We simulate supercontinuum generation in a fiber pumped by noise-like laser pulses for possible use in mid-IR spectroscopic breath analysis. The study uses a commercially available InF₃ ZBLAN fiber and a Tm-doped all-fiber passively mode-locked laser. The supercontinua are modeled with input laser parameters in two different generation regimes with an average power of 560 mW and pulse durations of 300 and 800 fs. The maximum numerically achieved spectrum extends from 1 to 8.4 μm.

The transient power characteristics of a singly resonant optical parametric oscillator is theoretically described. When analyzing we apply the time delay mathematical model. It is shown that the system demonstrates a variety of regimes with the variation of control parameters.

We present a theoretical investigation of two longitudinal mode microelectromechanical system (MEMS)-tunable vertical-cavity surface-emitting laser (VCSEL). The spatio-temporal dynamics of semiconductor laser with particular focus on the parameters relevant for THz photomixing is studied. A four-level model which allows for the polarization of the laser field by including the spin sublevels of the conduction and valence bands of a semiconductor is introduced. The maximum obtained wavelength separation between modes is ~30 nm which corresponds to 3.77 THz in frequency range.

In this paper, spatiotemporal dynamics of broad-area lasers with external optical injection is investigated. We demonstrate theoretically that relatively small optical injection suppresses unstable transverse modes and stabilizes laser output. We perform our study, taking into account the detuning between the frequency of the injected and generated radiation. The frequency detuning does not destroy the stabilizing effect. Parameters of the injected signal, at which effective suppression of transverse instabilities occurs, are found.

In this article we consider the problem of choosing the optimal parameter settings for measuring corneal thickness in the modified laser triangulation method. The accuracy of the method depends on the resolution of the light marks. For better resolution in this study we've chosen angles of viewing of the laser radiation (0.88 radians) and the position of the photodetector (0.17 radians). We calculated the maximum permissible laser power (0.1 mW), for which the tissue under investigation is not damaged yet: there is no ablation, scar formation and a change in the refractive index.

In this paper we consider the problem of determining the most optimal parameters of an apparatus for measuring the thickness of the cornea in an interferometric method. Earlier, a formula was derived to determine the thickness of the corneal layer, taking into account the radius of curvature in the range from 0.5 mm to 1 mm and an error of 0.5-1.0%. The accuracy of the method depends on the quality of the determination of the thickness of the interference fringes. We consider the possibility of using this method for measuring tissue thicknesses over a wider range of values. The optimum values for the angle of incidence of the radiation we was selected by the experimental and calculation methods: 0.07 radians for the range from 0.01 mm to 0.1 mm and 0.17 radians for the range from 0.1 mm to 1 mm. We give a scheme of a simplified construction of an interference thickness meter and experimental interferograms with computer processing.

Laser self-mixing interferometry of absolute distances is represented by the method of frequency modulation of supply current of the laser diode (FMCW technique). The advantages of the triangular wave modulation method in combination with the use of the frequency of the self-mixing signal spectrum have been shown. The advantages of the harmonic wave modulation method in combination with the use of the some various amplitudes of the self-mixing signal spectrum have been shown were shown also. The advantages of the harmonic wave modulation method in combination with the use of different amplitudes of the spectrum of self-mixing signals are shown. The equipment includes a frequency-modulated semiconductor self-mixing laser diode RLD-650 on quantum-size structures with a diffraction-limited single spatial mode with a wavelength of 654 nm. The results of computer simulation showed that the accuracy of determining the distance at the harmonic wave modulation decreases with increasing the distance to the measured object. But at small distances, its value is much smaller than at the triangular wave modulation of laser radiation.

In this work, we investigate the spectral and polarization characteristics of a vacuum photosensor with a nanoscale molybdenum blade as a sensing element. The results of theoretical and experimental studies of the optical fields in the sensor and the photocurrent produced by laser beam irradiation in the range of wavelengths from the visible to the near infrared are presented. The existence of a photo-response far beyond the red threshold of the classical photoelectric effect is ensured by the localization of an external strong electrostatic field. Features of the field interaction of radiation with a molybdenum blade cause the registered spectral non-monotonicity of the photocurrent value, which corresponds to the results of theoretical studies. The ballistic transport of electrons in a vacuum is characterized by a high speed. Achieved results made the photosensor based on nanoscale molybdenum blade promising in the development of ultrafast vacuum micro and nanoelectronic devices.

We have propose an original approach for fabrication of flexible antennas for biomedical-related applications. The technology is based on magnetron sputtering and laser ablation methods. The magnetron sputtering method is used to deposit a thin layer of metal (copper) on a flexible substrate (polyimide film). Then laser ablation is utilized to remove excess copper thus forming an antenna pattern on the metal layer. ISM band flexible design with microstrip feeding structure was chosen for testing this technique. Results of numerical simulation are presented. A number of test flexible antennas were fabricated by our original approach. Similar flexible antennas were also fabricated via photolithography process. A comparison of the experimental results of return loss (S11) measurements of antennas with different fabrication approach was carried out. The obtained experimental data is in a good agreement with the numerical modeling results. Proposed technology has significant advantages in cost, speed, and flexibility over photolithography processes commonly utilized for such applications.

We consider the results of modern scientific literature review on the experience and possibilities of using resistive thinfilm layers in vacuum electron devices (resistive wall amplifier). Such thin-film layers can be used as analogue of conventional slow wave structures in vacuum microwave amplifiers. The disadvantages of conventional slow wave structures in millimeter and submillimeter wavelength ranges are discussed. The main advantages and features of resistive thin-film layers, which could be serve as slow wave structures in amplifying devices of vacuum microwave electronics of millimeter and submillimeter wavelength range, are revealed. The proposed review covers the period from 1953, when the idea of a resistive wall amplifier was first introduced, to 2018. It was shown that the majority of literature consist only theoretical results, only a few papers consider the experimental results. Also it is noted that the focus of modern study shifts to the using of metamaterials as a resistive thin-film layer, very promising theoretical results and some cold measurements were obtained only in the GHz region.

The results of analytical and numerical analysis of propagation of short probe pulses of electromagnetically induced transparency in the case of control field elliptic polarization are presented. The situation is explored, when the probe field is weak comparison with control radiation. Then the probe pulse in the medium is a sum of two elliptically polarized pulses, which travel without interaction among themselves and have invariable states of polarization. This fact permits to term these pulses nonstationary elliptically polarized normal modes. Numerical simulation shown, that normal mode structure is determined by the ratio of spectral width of input probe pulse to spectral width of quantum transition, which is resonant to probe emission. When this relation is small, each mode in the medium is the pulse similar to input probe pulse. If this relation is large, the mode envelopes are distorted, when mode pulses travel in the medium. In this case, probe pulse absorption increases considerably. The theoretical investigation is performed for the  -scheme of degenerate quantum transitions between ³P₀ , ³P₁⁰ and ³P₂ energy levels of ²⁰⁸Pb isotope.

The phase-matched conditions for waves interactions, which are used in different optical elements and complex devices, are necessary practically as a rule for obtaining the sufficiently big energy efficiency and also for realization of a high angular selectivity of the interacting light signals. In this paper we present the analysis of the realization of the phasematched conditions for the light interacting of the different frequencies on the photo-induced susceptibility gratings, which can be created, as now it is known, in different isotropic materials (the glasses, polymers and hybrids). The interactions of the light radiations with various frequencies on the photo-induced susceptibility gratings with small periodicities are discussed and the potential possible bandwidth from the visible and near infra-red spectrums is analyzed.

The analysis of the summary investigation results of a nonlinear process of generation of the laser frequency harmonic on the second-order susceptibility gratings photo-integrated in different consisted glass materials are presented. The basic attention is concentrated on the results of study of the properties of the frequency harmonic generation in oxide materials with the variations of the concentrations of the lead-oxide, the some elements of the first-five groups and the rare-earth elements. The influence of the variations of the chemical components on the formation of the photo-integrated second-order susceptibility gratings in investigated samples and also on the process of the frequency harmonic generation is analyzed.

Quantum fluctuations of soliton pulses produced via two-soliton fission in the optical dispersion oscillating fiber were investigated using perturbation analysis and back-propagation method.

In this paper, the propagation of nanosecond laser pulses in various media with reverse saturable absorption is studied by numerical methods. Numerical simulation of the propagation of nanosecond laser pulses in a three-level medium with reverse saturable absorption was carried out using the classical transport equation for the case of incoherent nonlinear interaction of radiation with the medium described by the proposed three-level model. The degree of pulse deformation in such media is estimated. It is shown that with an increase in intensity, the pulse begins to deform, the pulse front shortens, the trailing edge becomes longer, the asymmetry coefficient increases. An additional maximum begins to form during a trailing edge with a further increase in intensity. As the additional maximum increases, the asymmetry coefficient monotonously decreases to negative values.

The propagation of short light pulses in a three-level medium with reverse saturable absorption taking into account relaxation is considered. It is shown that in such a medium soliton-like pulses of constant duration can propagate. The areas in the five-dimensional parameter space in which such pulses can exist are determined by numerical methods. The parameters of the problem are the characteristics of the medium – the relaxation time, the ratio of the absorption cross sections of the first excited and ground states and the initial transmittance, as well as the characteristics of the pulse – the duration and intensity.

In this paper, we investigated the entanglement dynamics between two superconducting qubits in the framework of not-resonant double Jaynes-Cummings model taking into account the direct dipole-dipole interaction. We explored the dependence of the atom-atom entanglement on the strength of the dipole-dipole interaction and detuning. The results show these parameters affect the period of negativity oscillations but not the maximum value of entanglement in contrast to two-atom Jaynes-Cummings model with common cavity mode.

This paper studies the entanglement properties in a system of two dipole-coupled natural or artificial two-level atoms not-resonantly interacting with an intensive single-mode thermal field for coherent initial atomic states. The results show that the entanglement is weaken due to the initial atomic coherence for model with detuning in contrast to the model with resonant atom-field interaction. For non-dissipative model under consideration the detuning results also in decreasing of the atom-atom entanglement in time for separable initial atomic state and intensive cavity thermal field.

A problem of the coherent control of a quantum system in an external electromagnetic field is considered. We use the technique of dynamical symmetry Lie groups and relevant coherent states. The general approach is illustrated by examples of qubit and qudit dynamics in an external classical field, and transitions between the Rydberg states of a hydrogen-like atom with the fixed principal quantum number. The problem of generalization of the approach for taking into account additional interaction with a large dissipative environment is discussed.

Quantum fluctuations of pump and Stokes pulses in the optical fiber Raman amplifier were investigated using perturbation analysis and properly adopted back-propagation method.

We investigated the entanglement of a quantum system consisting of a Jaynes-Cummings atom, thermal lossless cavity and an isolated atom. The analytical expressions of the atom-atom negativity for separable, separable coherent and entangled initial atomic states were obtained. The influence of initial atomic coherence, detuning between the atomic transition frequency and the field frequency and direct dipole-dipole interaction on an atom- atom entanglement is examined. We showed that for a separable and separable coherent initial atomic states a detuning might cause high atom-atom entanglement in the presence of the dipole-dipole interaction even for thermal field with high intensity. We also obtained that for entangled initial atomic states a detuning causes a stabilization of an entanglement oscillations.

We considered a quantum model consisting of two effective two-level atoms interacting with a single-mode thermal cavity field through two-photon transitions. We explored the entanglement dynamics between two atoms, and studied the effect of the Stark shift on the entanglement. The results showed that for a separable initial atomic state the Stark shift enhances the amount of atom-atom entanglement induced by the thermal field. For entangled atomic state the Stark shift reduces the the atom-atom entanglement oscillations.

When the Maxwell equations are geometrized, the Maxwell Lagrangian is usually reduced to the Yang-Mills Lagrangian. In this case, the effective quadratic metric, usually corresponding to the Riemannian metric of our space, is considered. However, it is more reasonable to use Finsler approach to Maxwell’s equations. In the paper the Finsler representation of the geometrized Maxwell equations is considered. The comparison with the Riemannian approach also is made.

The most common physical formalisms are the Lagrangian formalism and the Hamiltonian formalism. From the superficial point of view, they are one and the same, but rewritten in other terms. However, it seems that the Hamiltonian formalism has a richer structure and is more convenient for studying the electromagnetic field, especially in the formalization of its geometrization. Unfortunately for field problems, there is a whole set of Hamiltonian formalisms. The authors study the applicability of different variants of the Hamiltonian formalism to the problems of electrodynamics. In this paper we consider the Hamiltonian formalism with constraints.

In the case of guided and radiation modes of open waveguides, the Sturm-Liouville problem is formulated for self-adjoint second-order operators on the axis and the corresponding eigenvalues are real quantities for dielectric media. The search for eigenvalues and eigenfunctions corresponding to the leaky modes involves a number of difficulties: the boundary conditions for the leaky modes are not self-adjoint, so that the eigenvalues can turn out to be complex quantities. The problem of finding eigenvalues and eigenfunctions is associated with finding the complex roots of the nonlinear dispersion equation. Leaky modes, by analogy with radiation and guided modes, are considered as solutions of the Helmholtz equation. The presence of complex eigenvalues corresponding to the leaky modes leads to an infinite increase of eigen- functions corresponding to the leaky modes. In the present work, the leaky modes are considered as solutions of the problem for the wave equation and are analyzed as a wave process. Complex eigenvalues define the leaky modes as inhomogeneous waves. The proposed approach allows to obtain a mathematically sound representation of the leaky modes, within which one can see the region of existence of each particular leaky mode. The calculations of model structure, demonstrating the application of the described approach, are presented in the paper.

The problem of reflection of a plane electromagnetic wave incident on a flat non-uniform anisotropic nematic structure is considered. The angular spectra of the energy reflection coefficients and the ellipsometric parameters of the reflected light are calculated using the matrix solution WKB. For comparison, the calculation was performed using the widely used 2 * 2 matrix method in a model of a layered medium. The advantages and limitations of the two methods are shown.

The dependence of the ellipsometric parameters and the coefficients of the reflection matrix on the torsion angle of an inhomogeneous gyrotropic medium is investigated. An oblique incidence of light is considered. For the calculation, a solution is used in the form of a 4 × 4 matrix obtained by the Ventcel-Kramers-Brillouin method.

The Maxwell equations have a fairly simple form. However, finding solutions of Maxwell’s equations is an extremely difficult task. Therefore, various simplifying approaches are often used in optics. One such simplifying approach is to use the approximation of geometric optics. The approximation of geometric optics is constructed with the assumption that the wavelengths are small (short-wavelength approximation). The basis of geometric optics is the eikonal equation. The eikonal equation can be obtained from the wave equation (Helmholtz equation). Thus, the eikonal equation relates the wave and geometric optics. In fact, the eikonal equation is a quasi-classical approximation (the Wentzel–Kramers–Brillouin method) of wave optics. This paper shows the application of geometric methods of electrodynamics to the calculation of optical devices, such as Maxwell and Luneburg lenses. The eikonal equation, which was transformed to the ODE system by the method of characteristics, is considered. The resulting system is written for the case of Maxwell and Luneburg lenses.

The maximum slowdown and the resonance frequency of plasmons in thin metallic layers and layered structures are obtained. We conside the anomalous negative dispersion and backward plasmons with dissipation. The conditions for the existence of inverse plasmons are obtained. It is shown that negative dispersion in structures with dissipation does not always mean the presence of reverse plasmon.

A technique of the low-coherence reflectometry was applied to characterize the structure of foamed polylactide matrices. This technique is based on the analysis of the decaying output of a low-coherence scanning interferometer with a diffusively backscattering probed sample in the object arm. Estimations of the decay rate for the interferometer output allowed us to characterize the influence of the foaming parameters on the mean transport free path of light propagation in the examined foamed matrices. It was established that foaming in the vicinity of the critical point of the plasticizing and foaming agent (carbon dioxide) leads to a smaller average size of pores in the synthesized matrices compared to the foaming parameters far from the critical point.

The results of the Monte Carlo radiative transfer modeling using scattering phase functions with the Henyey- Greenstein (HGPF) and the Gegenbauer kernel (GKPF) are presented. The Monte Carlo modeling of the light transport in the tissues with complex structures and dynamics is used as an original approach of speckle-correlometry based on the ring-like apertures and localized source of the probe light. The backscattering coefficient of the laser light scattered by the simulated medium was evaluated. The inhomogeneous layer, which contains a long inclusion with a different geometry and depth location for imitatng the blood vessel inside medium, was chosen as a simulated medium. The values of the scattering phase function with the Gegenbauer kernel are reduced to the values of the Henyey-Greenstein scattering phase function when the annular light detector has small radii, whereas for the annular big radii this transition is not carried out.

Low-coherence reflectometry with the intensity moments analysis in application to laser-pumped dye-doped random medium characterization is discussed in this paper. A fluorescence radiation induced by the laser pumping formed a stochastic interference pattern. The established relationship between the second and third-order moments of multiple scattered fluorescence intensity, the coherence function, and the probability density distribution of the path length differences obtained using the Monte Carlo modeling allows us to characterize the general tendencies relating suppression of the stochastic interference of the quasi-monochromatic light in random multiple scattering media.

This work describes the results of analysis of the developing porous systems and foamed liquids using full-filed speckle correlometry. The relationship between the dynamics of structure formation of the model porous matrices and the correlation time of multiple scattered laser light is studied. Partially isolated foam samples were used as model scattering objects. The observed increase in the correlation time of speckle intensity fluctuations is caused by a variety of physical processes occurring in the evolving foam (in particular, the gas diffusion between neighboring pores). The obtained results can serve as the physical basis for advanced probing techniques in various areas of modern applied science related to synthesis of highly porous functional materials.

This paper presents the results of study devoted to the laser speckle imaging method application for characterizing the combustion of aluminum nanopowder in air. The experimental schema is introduced for the combustion process characterization. The main advantage of speckle imaging is the ability to study the surface of the burning sample despite high-temperature bright glow. Analysis of the image correlation coefficient allows us to obtain the temporal parameters of the burning sample surface changes. The experiments have shown the applicability of the method of speckle imaging of combustion processes study.

The main objective of our study was to identify and recover the depth distributions of the backscattering efficiency in macroscopically heterogeneous stratified media. The recovery technique is based on analysis and processing of the backscattering response of an examined medium in the case of its low-coherence reflectometric probing. In our case, the commercially available swept-source OCT system was applied as the instrument for low-coherence reflectometry. The discussed technique was applied to characterization of in-vivo human skin in the normal state and after optical clearing.

In this paper, we consider possibilities to compensate the chromatic aberration effects in the swept source optical coherence tomography system with line-field illumination (LF SSOCT) in spectral range 1260-1360 nm and reflected light acquisition by linear array InGaAs photo detector. Compensation of chromatic aberrations is provided by combined use of optimized optical system design with sharp focusing independent on light wavelength and fringe processing algorithm which allows accurate spectral fringe frequency evaluation even in the case of nonlinearity of the wavenumber tuning. Experimental results confirmed significant enhancement of imaging quality including LF SSOCT mode.

The spectra of mode loss in terahertz quantum cascade laser (THz QCL) with double metal waveguide (DMW) based on Au, Cu and Ag have been analysed. On the basis of measurements of the resistivity of DMW claddings for the temperature range from 4.2 to 300 K, the loss coefficients of THz radiation at Au-, Cu-, Ag-claddings are calculated. We show that the Ag-based DMW allows to reduce the losses by 1.3–7.0 cm^-1 in comparison with Au-based DMW at room temperature. Our calculations show that the Ag-based DMW has slightly lower losses (~1 cm^-1) than Cu-based DMW at cryogenic temperatures (below 100 K). The use of Cu-based DMW allows to reduce the loss coefficient in comparison with Ag-based DMW at higher temperatures (above 100 K). Temperature dependence of threshold gain for THz QCL with Au-, Cu-, Ag-based DMW are calculated. Taking into account the absorption of THz radiation by free carriers and optical phonons, the spectrum of total mode loss of THz QCL with different thickness of n+-GaAs top contact layer are analyses.

The linear theory of a traveling wave tube (TWT) or vacuum amplifier with a wide tape electron beam operating on plasmon modes is developed. The dispersion equation for electron waves and the gain per unit length with account for the dissipation in the structure are obtained. Strict solutions for dispersion and field distribution of surface plasmons in layered structures with conducting films and for electron waves amplified by a beam are obtained by the iteration method. To increase the gain, it is proposed to use active conductive semiconductor or graphene layers.

THz wave emission in the cavity which contains the graphene-multilayer asymmetric hyperbolic metamaterials is investigated numerically using transfer matrix method. In was assumed that the gain saturation appears as the decrease of imaginary part of effective dielectric permittivity. Gain –loss balance predicts the intensity of THz lasing.

Amplification of terahertz plasmons in tapered metal-insulator-graphene heterostructure is studied. It is shown that the plasmon energy density and the energy flux can become more than two orders of magnitude greater as compared to the same values in active pristine graphene.

We theoretically investigate the excitation of plasmon resonances in a double-layer periodical graphene PT-symmetric microribbon structure. It is shown that the condition of PT-symmetry for graphene plasmonic structure is achieved at discrete frequencies for the set of realistic graphene parameters in terahertz frequency band, even at room temperature. The regimes of total reflection of THz wave at PT-symmetric plasmon resonance can be reached in periodical graphene microribbon structure.

Microfabricated vacuum power amplifiers and oscillators operating at millimeter and submillimeter (THz) bands are of great interest for applications in high-speed communication, radar, security and military systems, electronic warfare, etc. In this work, we report the results of numerical simulation and cold-test measurements of electromagnetic parameters of the V-band (50-70 GHz) planar meander-line SWS. The microstrip meander-line SWS is suitable for using in a millimeter-band TWT amplifiers. Several samples of copper microstrip meander-line SWS on a quartz substrate consisting of 50 meander periods with input and output couplers were designed, microfabricated and optimized. The SWS was microfabricated by using magnetron sputtering and laser ablation processes. This technique is a more facile, flexible and lower cost as compared to photolithography method. Transmission and reflection of proposed SWS were measured experimentally and calculated numerically. The results of the experimental cold-test measurements are verified by numerical simulations. Electromagnetic parameters of the SWSs were simulated using the finite-element ANSYS HFSS and COMSOL Multiphysics software packages. The results obtained with these two codes are in excellent agreement with each other and good agreement between experimental and numerical results is also observed.

The eigenvalue problem for second-order ordinary differential equation (SOODE) in a finite interval with the boundary conditions of the first, second and third kind is formulated. A computational scheme of the finite element method (FEM) is presented that allows the solution of the eigenvalue problem for a SOODE with the known potential function using the programs ODPEVP and KANTBP 4M that implement FEM in the Fortran and Maple, respectively. Numerical analysis of the solution using the KANTBP 4M program is performed for the SOODE exactly solvable eigenvalue problem. The discrete energy eigenvalues and eigenfunctions are analyzed for vibrational-rotational states of the diatomic beryllium molecule solving the eigenvalue problem for the SOODE numerically with the table-valued potential function approximated by interpolation Lagrange and Hermite polynomials and its asymptotic expansion for large values of the independent variable specified as Fortran function. The efficacy of the programs is demonstrated by the calculations of twelve eigenenergies of vibrational bound states with the required accuracy, in comparison with those known from literature, and the vibrational-rotational spectrum of the diatomic beryllium molecule.

Fourier spectroscopy was used to experimental research the infrared (IR) spectrum of arginine in petroleum jelly. The structure and spectra of the L and D -arginine molecule have been modeling by Hartree-Fock method. The vibrational IR spectra of the zwitterionic forms of L, D-arginine were interpreted by analyzing the vibration shape with a certain frequency and calculated frequencies of normal modes, electro-optical parameters, force constants. Molecular configurations corresponding to thermodynamically stable states of arginine isomers have been determined.

Issues related to the problem of convergence of the series of the perturbation theory in the quasipotential approach are considered. New fine structure constant logarithmic contributions to the fine shift of the energy levels, vanishing in the limit m₂ rightarrow m₁ are discussed.

The results of molecular modeling of ascorbic acid electronic spectra in different solutions are represented. Geometric parameters and characteristics of electronic spectra of an isolated molecule and a molecule in solutions are determined within the framework of two models of solvation. It was shown that the increase of the dipole moment and the dielectric constant of the solvent leads to shift in the spectral bands and a change of the oscillators strength of the electronic transitions.

The results of in vivo optical immersion clearing of human skin under the effect of aqueous solutions of some immersion agents (monosaccharides of ribose, glucose and fructose, as well as glycerol, a triatomic alcohol) were obtained with the use of the OCT method. Values of average velocity of scattering coefficient change, obtained through an averaged Ascan of the OCT signal in the region of derma with the depth of 350 to 700 μm, were determined to evaluate the optical clearing efficiency. The velocity of scattering coefficient change and the optical clearing potential value appeared to be well correlated. The complex molecular modeling of a number of immersion clearing agents with a mimetic peptide of collagen (GPH)₃, carried out with the use of the methods of classical molecular dynamics and quantum chemistry, allowed to identify correlations between the optical clearing efficiency and such a property as the energy of intermolecular interaction of clearing agents with a collagen peptide fragment.

The electronic absorption spectra of two bovine serum albumin fragments containing tryptophan residues [Trp(134) and Trp (213)] were calculated and interpreted. The electronic spectra of both fragments were compared and the influence of amino acids in their composition on the electronic absorption spectra was considered. It was shown that the electron spectrum of lysine has absorption bands in the region above 300 nm, and the spectrum of alanine – absorption band in the region of 250-300 nm.

Vibrational IR and Raman spectra of fullerene derivatives – fullerene-glycine (C60-Gly) and fullerene-phenylalanine (C60-Phe) were calculated. The parameters of hydrogen bridges of hydrogen bonds formed by water molecules with Gly and Phe fragments were determined. The vibrational spectra are analyzed and the frequency and intensity shifts corresponding to the q(OH) and q(NH) valence vibrations in the formation of hydrogen bonds were identified.

The probability of quantum transitions of a molecule between its states under the action of an electromagnetic field is represented as an integral over trajectories of a real alternating functional. A method is proposed for computing the integral using recurrence relations. The method is used to describe the ionization of hydrogen atom.

New types of europium complexes with 2,2’-bipyridyl-based ligands were synthesized and their photophysical properties were studied in detail. The influence of the amidic-group substituents on the stability of their complexes with lanthanides also investigated. The branching of the substituent at the amidic group decreases both the quantum yields and stability of complexes.

In the present work discusses the factors affecting the brightness and intensity of the photoluminescence of the red phosphor glow based on yttrium oxysulfide activated by europium. The energy during cathode excitation is transferred from the surface of the grain to it is volume either due to the excitation of bulk plasmons (excitation 100 –400 V) or by the migration of minority charge carriers at low voltage (less than 100 V) excitation. With such mechanisms of energy transfer, the optimum grain size of phosphorus is about 1 micron. Therefore, surface treatment was carried out with modifying additives molybdate and ammonium tungstate grains of Y₂O₂S:Eu phosphors, which makes it possible to obtain powders with a spherical shape of grains not larger than 3-5 μm.

Based on the non-perturbative kinetic theory of the electron-hole pair excitation (EHE) in graphene under influence of a variable electromagnetic field, we investigate some features of the nonmonotonic evolution of entropy in the framework of the low-energy approach for different configurations of the linear and circular polarization laser fields. Such a character of the entropy change in graphene is stipulated by the action of the external field and the difference in the in− and out− states of the system, which is characteristic for field-induced phase transitions. A similar effect is known in the theory of the vacuum creation of an electron-positron plasma (EPP) under the action of a strong electromagnetic field, but has its own features.

This paper presents the results of prognostic modeling of the process of filling graphene nanoblisters with hydrogen. To carry out numerical molecular dynamics experiments, atomistic models of graphene nanoblisters were constructed in accordance with the data of a natural experiment. A numerical estimate of the mechanical stability of blisters containing structural defects of the atomic network is given. The effect of defects on the process of filling a blister with hydrogen has been studied. It is established that in the process of filling with a blister of hydrogen, atomic hydrogen is almost completely transferred to molecular. For the constructed models of blisters, the limiting concentration of stored hydrogen was found.

This work is devoted to the study of the electronic properties of graphene-carbon nanotube composite films with horizontal packing of tubes between graphene sheets. Using original method of magnifying glass we constructed the super-cells of mono- and bilayer hybrid composite films with different topology. The influence of topology - the chirality of nanotubes and the distance between them - on the electron-energy characteristics of graphenenanotube composites is studied. Using the self-consistent density functional tight binding (SCC DFTB) method, classical molecular dynamics with application of the AIREBO empirical potential and the method of nonequilibrium Green's functions we revealed new physical laws of the hybrid carbon nanostructures under consideration.