R e g u l a r p a p e r s

Radiophysics, electronics, acoustics

Memoirs of the Faculty of Physics 2015. N 4.

In this paper described the operability of some quantum optical circuits which depends on their constructions, such as reflectivity of beam splitters in the linear optical controlled-NOT gate in the coincidence basis.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Raman-Nath nonlinear diffraction in the process of second harmonic generation in two-dimensional nonlinear photonic structures is considered. An analytical expression for the calculation of spectral-angular characteristics of radiation is obtained. Nonlinear structure is optimized by the method of superposition of nonlinear susceptibility modulation to obtain efficient multiple second harmonic generation.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The system of the equations describing dynamics of parameters of the supergaussian pulse propagating in isotropic dielectric as in the field of normal, and abnormal dispersion of group speed is received.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The paper presents the results of experimental studies of the diffraction efficiency and selective properties (angular and polarization selectivity) of holographic inhomogeneous photonic structures formed in composite polymer-dispersed liquid crystals with different concentrations of the initial mixture components. Prepolymer mixture component composition was optimized in terms of the photonic structure diffraction efficiency maximum. The dependence of the samples diffraction and polarization characteristics on the external electric field value were obtained.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Formation of two-dimensional channel waveguides and couples of such waveguides within a bulk of undoped lithium niobate has been experimentally demonstarated. Waveguide structures with a channel diameter of 23 μm have been formed by the bright spatial solitons obtained at the compensation of the diffraction divergence of light beams in the crystal due to the contribution of the pyroelectric effect into the nonlinear response. The light wavelength was 633 nm and the optical power was ranged from 1 μW to 1 mW in experiments. The total compensation of the diffraction divergence at uniform heating of the crystal sample to the temperature from 35 degrees.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Experimentally investigated the characteristics of laser diodes (LD) operating at the wavelength of 530 nm. It is established that the contrast of the radiation power of the LD is small (less than 0.85) and very sensitive to changes in heterostructures. Contrast and radiation divergence (about one degree) are compared with the spectral characteristics of the LD.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The possibility to identify the nanocluster formations with star geometry based on the definition of the scaling parameters as in diffraction patterns of the probing radiation and within the analyzed objects is considered.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Methods of computer simulation were used for investigating of the effect of the guiding magnetic field on the characteristics of the radiation pulse of the multi-wave Cerenkov generator. It is shown that the dependence of the maximum radiation power of the value of the magnetic field is resonant.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

We investigate the quantum walks and generation of photon pairs in twisted waveguide arrays. We show that the correlation properties of photon pairs in this case can be adjusted by changing the waveguide twist angle of the and the profile of the pump amplitude at the input to the array.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The paper is devoted to investigation of 1,8 nm and 2,3 nm cadmium selenide quantum dots crystallized in glassy matrix. Nanoparticles were grown inside the liquid crystalline mesophase of pure cadmium octanoate. During the process of synthesis nanoparticles stabilize and orient inside a matrix. Spatial homogeneity of the samples was studied using Spatially-resolved epi-luminescent luminescence microscopy technique. Correlation between quantum dots sizes and sample structure was observed.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

We suggest the theory describing generation of a harmonic resonant with the transition from ground to autoionizing state of the generating particle. Calculating both harmonic amplitudes and phases, we study the attopulse generation using these harmonics.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

By numerical simulation the stability of fractal characteristics in the optical characteristics of aperiodic multilayer systems with metamaterials is investigated. The conditions of pattern formations in the spectral characteristics of the analyzed systems are identified. Particular attention is given to the estimation of transformation form of the reflection spectra of systems with different geometry and taking into account dispersion effects.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

A technology of creating LC elements which can perform space-polarization control of laser radiation was developed. The effect of total internal reflection from a controlled refractive boundary of two LC areas with orthogonal director orientation was realized.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

We have studied the response of the graphene with a gap to external dc and ac electric fields without using of low-energy approximation for the energy carrier that allows us to study the effects of a broader range of parameters of applied electric fields. The electronic system of graphene described by Boltzmann's kinetic equation in the constant relaxation-time approximation. The amplitude of the higher harmonics on the characteristics of applied fields is studied.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Spectral properties are investigated of a photonic crystal conjugated to nanocomposite containing particles comprised of a dielectric core and a metallic shell. In the spectrum three features are obtained: optical Tamm states; photonic band gap; stopband associated with absorption.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The interaction of a short optical pulse with refractive index lattice induced in the nonlinear medium by the pulsed quasi-periodic structures at similar frequencies is considered. The results of numerical simulation of reflection, transmission, multiplexing signal pulse into several sub-pulses for different induced gratings are presented.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The photon-drag effect in a semiconductor superlattice due to intraband absorption of a bichromatic electromagnetic wave in phonon absorption has been covered. The problem is solved using the second order perturbation theory. The multiphoton absorption is taken into account. Direct drag current component is analyzed in the frequency wave. Drag current increases the field. When peaking, it decreases, oscillating.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The article deals with the effect of local increasing the sensitivity of nonlinear Granger causality with the growth of a noise. The method is applied to coupled nonlinear model systems with both discrete and continuous time.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In the present study a comparison of the original approach and five known methods is carried out via analysis of periodic data in the presence of measurement and dynamical noise.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Mathematical model for investigation of vacuum limiting current in a drift channel of terahertz region microwave device is considered. Finite element method which allows to consider arbitrary cross-section geometry of the channel and electron streamis used for calculations.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Consider the inclined with respect to the radiating plane propagation of high intensity acoustic beams in the medium with gas bubbles. The approximation of the d'Alembert operator is suggested, which allows us to derive the evolution equation suitable at all angles of beam propagation. The Khokhlov-Zabolotskaya type equation for oblique beam propagation in a medium with gas bubbles is set up.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The main aim is to develop a method for calculating the structure of the wave field in a heterogeneous medium of skull bone. Phantoms of cranial bones were created and measurement techniques of their acoustic parameters were developed. Principal ultrasonic reconstruction of the real skull bone profile was accomplished.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Vortex beams are waves those are able to give torque to a small obstacle. In this research in order to create a vortex beam the special phase screen is used. Such screen turns originally plane wave in helical. The experiment is conducted and modeling in the program MATLAB is made.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The problem of digital holographic imaging in arbitrary spectral intervals is discussed. Optical scheme based on Mach–Zehnder interferometer with use of acousto–optic filtration of broadband light is presented.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In this paper it is investigated the gain of the vertical antenna array which is situated in a randomly inhomogeneous underwater sound channel. The model of the received on the array signal is defined as the superposition of normal waves with specified spectrum of wave numbers and with random amplitudes. The radius of mutual correlations of modes is depended on the distance of signal propagation. The amplitude-phase distribution, defined on the antenna array, was allowed us to adapt to any of the propagating modes. In addition, it is considered two different types of ocean noise, namely, the model of noise with continuous and discrete-mode spectrum. As a result it is analyzed the dependence of response of the vertical antenna array on such following parameters as: the spectrum of modes intensities of signal, the range of the wave numbers and the scale of cross-modal correlations.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The polarizabilities of subwave spherical silica glass particles are investigated with taking material dispersion into account. It is shown that the ranges of negative values for electric and magnetic polarizabilities are practically coinciding. This permits to use such particles for constructing of the medium with negative refractive index.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In this paper, an algorithm that allows to design metafilms, consisting of spherical particles, with given spectral properties is proposed. The solution is constructed analytically, the algorithm can be easily integrated with natural experiment

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Stability of sheet electron beam with cyclotron rotation in the axial symmetric magnetic field was studied. It was shown, that at the expense of increase in area of beam cross-section in the divergent magnetic field smaller deformation of a transverse cross-section of the beam may be reached

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The experimental studies of fast dynamics in a wedge of polycrystalline aluminum alloy with residual stresses with V-waves were carried out. As a result of the analysis of experimental data this method can be used to detect the presence of defects.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

For nanocomposite and photonic crystal interface a complete theoretic study of optical Tamm state is presented. The nanocomposite consists of prolate metallic nanoparticles dispersed in a transparent matrix. It is characterized by resonant effective permittivity; whereas the optical properties of the initial materials have no resonant features. The nanocomposite anisotropy optimizes Tamm state localization and makes the photonic band gap wider.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Methods of acoustical tomography of the third-order nonlinear parameter for the purpose of medical diagnostics are considered. Tomographic schemes based on noncollinear interaction of three coded waves, allowing to obtain numerical values of nonlinear parameter, are preferred.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

We proposed the mathematical model for the collective dynamics of charge in a semiconductor heterostructure which presents itself as a chain of semiconductor superlattices divided by heavy doped regions. Using the developed model we considered this structure operated in a mode characterized by the reinjection of charge domains from one superlattice to another.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

This paper presents an acousto-plasmonic modulator design in far infrared based on surface plasmon resonance. Interaction of surface plasmon polariton with surface acoustic wave has been calculated

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Dynamics of electron beam with cyclotron rotation was studied at flat-symmetric reverse of magnetic field. It was shown, that spatial grouping of electrons is possible without modulation of initial longitudinal velocity.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

A mathematical model for investigation of dispersion of hybrid spin-electromagnetic waves in multiferroic heterostructure of two magnonic crystals separated by ferroelectric slab is derived. Possibility of electrical control of band gap’s characteristics in microwave range is demonstrated

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The semiconductor superlattice is the composite nanostructure used for the generation and the control of the high-frequency oscillations. At present time, attention of the researchers is attracted to the nonlinear dynamics of the electron domains at present nanostructures. In this paper the period-doubling bifurcation phenomena in the semiconductor superlattice under the influence of the titled magnetic field for different temperatures is described.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The intermittent behavior that can occur in the chaotic systems with the signal filtration near the boundary of the phase chaotic synchronization regime onset is studied. In the framework of the researches carried out we have found that in the system of unidirectionally coupled generators on the tunnel diode the eyelet and ring intermittencies are possible to exist simultaneously near the boundary of the phase chaotic synchronization with the use of the filter with certain parameters.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

This paper describes the results of an experimental observation at room temperature effect NonFaraday rotation of the polarization vector of signals femtosecond stimulated photon echo excited in a three-layer semiconductor film ZnO / Si (P) / Si (B).

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The optical absorption influence on the diffraction broadening of a laser beam in iron-doped lithium niobate crystal samples has been studied. The effect of the partial compensation of the laser beam nonlinear diffraction broadening has been revealed which is due to the pyroelectric effect contribution into the nonlinear response because of the material heating within the illuminated region at light wavelength of 532 nm.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The questions related to possible mechanisms of rogue waves formation in the ocean by the wind. Presents data on the formation of solitary waves (rogue waves) in the annular aerobasin

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The research results of self-consistent dynamics by ensemble of the self-oscillators and two-dimensional coaxial field are presented. Results in field of modeling class of signals which have inhomogeneous space-time structure are presented. On the basis of computational experimentation methods formation modes in wave field and modulating effect of corrugation on this process are researched. The possibility of formation clear mode are showed.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Formation of square optical vortex lattice was investigated using Maxwell-Bloch system. Reduced system describing nonlinear interaction of four waves was obtained. A square optical vortex lattice also was obtained numerically.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The propagation of sound in shallow water was studied. The recording of signal to several distances from the source was held. The amplitudes of the signal spectral components at these points were calculated. The dependence of the attenuation coefficient on the frequency was obtained by the maximum likelihood estimation.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Soliton dynamicsin amedium with a cascade nonlinearity in the presence of a local modulation nonlinearity coefficient in the form of two parallel defects wasstudied. The conditions under which there may be a regimeof soliton refraction by defects and regimeof soliton trappingby a particular channelwereinvestigated. It was shown that the soliton trapping depends on the soliton parameters (amplitude, the angle of incidence on defect), and the parameters of defects (nonlinearity coefficient of the modulation depth, shape)

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Currently not enough investigated both experimentally and theoretically the ratio between the length, amplitude and velocity of such waves. For this reason, this work is devoted to the study of these relations by means of mathematical modeling.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In the article the algorithm of eigenmodes calculation of three-gap axially symmetrical resonator of klystron is under consideration. The “nearly R-functions” approach is applied to describe the resonator structure. The finite-elements method with application of atomic functions as basic functions is used for calculations. It provides the high speed of convergence and significant efficiency of the algorithm.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Acoustical waves scattering on the inhomogeneity of medium density and compressibility is considered in the article. This inhomogeneity has small wave size. The maximum possible scattered by such kind of inhomogeneity power is achieved in 1D, 2D and 3D cases.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The main aim of the work is to create a numerical model of acoustic wave propagation in rigid rod. Vibrations of the end of the rod will be recorded by an optical method. Developed model can help to find the optimal parameters to create a real physical system for the efficient optical registration of the acoustic signal.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Presents the results of measurements of the velocity of shear waves in a CIRS phantom, which contained spheres of different diameters and located at different depths. The measurements were made on the Verasonics ultrasound system using the SWEI methods.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The simplest chiral autowave structures are formed in dissipative systems, in active media. As a result of biological evolution as the spiral and supercoiled hierarchical structures they become a constructive basis of the molecular machinery of cells — proteins and nucleic acids

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

The results of numerical simulation of the interaction between the relativistic electron beam focused by constant magnetic field and the field of an axisymmetric overmoded periodic waveguide are reported. Cyclotron resonant signal amplification and cyclotron absorbtion ranges were revealed, the dynamics of beam electrons was studied, as well as the role of beam parameters that affect the cyclotron resonance.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Presentation about visualization of deuterium and perfluorocarbons distribution in rats using multinuclear NMR spectroscopy and MRI. It is shown that the use of multinuclear MRI visualization offers great promise in biological and medical research in vivo.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In this work it has been experimentally and theoretically investigated the relationship between the slow degradation of high-power semiconductor injection lasers with quantum well (InGaAs/InGaAsP) and their spectra, radiation pattern and polarization of the radiation. For the theoretical description of the phenomena we use an independent channels model for generating radiation.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In this paper the system of two coupled Rydberg atoms is studied. Chaotic dynamics is revealed and the method for suppression of chaos in the system is selected.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

For a number of tasks when using pulsed ultrasonic beams it is important to be able to predict the acoustic field generated by the transducer. In this paper the method of reconstruction the space-time structure of the acoustic field on the surface of the acoustic pulse sources is proposed.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

This paper presents study analogues of classical problems of Rayleigh and Stokes considering shear component of the acoustic field in the liquid and identified a special role of the shear viscosity and the degree of influence of the shear component of the acoustic field on its characteristics.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

In this work we consider the mathematical model of wide-aperture laser described by the set of Maxwell-Bloch equations. It is shown that the cascade of bifurcations of periodic and quasiperiodic dynamical modes is occurred at increasing of pumping parameter.

Show AbstractMemoirs of the Faculty of Physics 2015. N 4.

Memoirs of the Faculty of Physics 2015. N 4.