Though phase-conjugation fidelity of stimulated Brillouin scattering (SBS) has been widely investigated, seldom attention is paid to pulse-shape fidelity. However, some applications of SBS phase conjugate mirror (PCM) require nearly identical SBS pulse shapes with pump pulses, i.e. high pulse-shape fidelity. To avoid the pulse compression effect in common SBS PCM, a novel scheme with a Stokes seed injection into the SBS generator is suggested and investigated experimentally. Experimentally results show that SBS duration becomes wider with increasing of the seed intensity, but shorter focal length can get wider duration. Pulse-shape fidelities at points of the widest duration are calculated as about 92% and 73% with focal lengths 5cm and 10cm respectively. Compared with 40% and 48% of cases without the Stokes seed, it is showed that seed injection improves the shape fidelity.

The heterogenous-chain mechanism of low-threshold initiation of heavy azides metal (HMA) is suggested. The recombination of azides-radicals on a HMA surface leads to generation of electron-hole pairs. Azide radicals are formed at trapping of holes surface levels of azid anions. The computer simulation of this mechanism is carried out. The computing were performed at different length and densities of energy of a laser pulse. The initiation delay depends on the characteristic time within which traps are filled by holes.

A 1.5m long cell, different focusing lens, a KrF laser which bandwidth is 0.5cm^-1, and SF₆ gas as Brillouin medium are used in the experiment. The influences of focus length and SF₆ pressure on threshold of stimulated Brillouin scattering excited by broadband KrF laser were investigated, respectively. The SBS threshold increases with increasing of the focus length and decreasing of the SF₆ pressure. The results show that the threshold of broadband SBS is various with the different focus length and SF₆ pressure. For more precisely to explain the experimental results, a novel model considering optical breakdown and pump linewidth was presented. The model we proposed here assumes that the KrF laser spectrum is made up of a seriues of narrowband spectra, each generating one Stokes wave. In addition, it is assumed further that the neighbors of one narrowband spectrum also contribute to the generation of its corresponding Stokes wave to some degree. Optical breakdown is assumed to lead to the loss of pumping energy only. The experimental results are consistent with the numerical theory.

Theoretical simulation and experimental studies of optical limiting characteristics in thin stimulated Brillouin scattering (SBS) cell of CCl₄ have been given. Temporal coupling equations of stimulated Brillouin scattering initiated by thermally excited acoustic wave's field-uniformity existing in thin SBS cell are used. In order to reveal optical limiting performance, several limiting parameters are discussed. The dependences of SBS limiting parameters on pump energy and length of thin SBS cell are studied numerically firstly. The results showed that non-focusing thin SBS cell can limit energy as high as several Joule magnitudes. Power and output energy limiting behaviors have been studied experimentally in our experimental regime. For 1cm thin cell, when laser pulses transmit through the SBS medium CCl₄; the output power and energy are limited fainlyt: the output peak power is limited and pulse narrowed without evident power limiting in the following edge; as for 2cm and 4cm cell, both show evident power limiting "step" and energy limiting characteristics, when pump energy increases from 5mJ to 100mJ, the output energy is limited under 20mJ for 2cm SBS cell and 12mJ for 4 cm SBS cell, which are quite agree with theoretical calculations in low input energy level.

The forward and backward cascaded stimulated Brillouin scattering (SBS) in the backward pumped S band distributed G652 fiber Raman amplifier have been researched, pumped by the tunable power 1428nm fiber Raman laser and signal source is a tunable narrow spectral bandwidth (<100MHz)ECL. The forward SBS does not obey the common theory, that only weaken backward-SBS lines existed, according to conservation of energy and momentum and wave vector selected rule. Because the wave-guide character weaken the wave vector rule, the forward transmit sound wave-guide forward Brillouin scattering lines are generated and amplified in S band G652 FRA. Forward SBS that is amplified phenomena of transmit sound wave Brillouin scattering in the G652 FRA, during pump power is larger than the threshold value of SBS in a S band G652 FRA. Two-order SBS in the Stokes region is observed during the pump power is increased. When the FRA pump power is further increased, Cascaded SBS lines and comb profile are observed.

In recent years, optical wave guided sensors have attracted scientists for the development of biochemical and biomedical optical sensors in addition to optical communicative devices. These sensors show immunity to electromagnetic fields and have no danger of ignition so that they are used in cases of risky environments. Optical sensors have additional advantages: higher sensitivity, higher stability and lower price. Surface sensing, in particular, is used in recognition of adsorption or deposition on a certain surface such as the detection of adsorbed proteins, antibodies and bacteria cells. In this work, a sensing layer (extra ultra-thin film) iss assumed to rest on surface of a thin film covered with a nonlinear clad of lief dependent refractive index. A normalized analysis for the design of evanescent wave sensors is carried out for linear waveguide sensors with normal asymmetry (i.e., substrate refractive index is higher than that of clad). Sensitivity of such sensors is evaluated and the condition for them to achieve maximum sensing is also introduced. A computer program was developed for the computation and then plotting results in the so called universal charts from which one can specify the appropriate dimension for the required sensor.

Two-wave mixing in sillenite crystals such as bismuth silicon oxide (Bi12SiO20) and bismuth titanium oxide (Bi12TiO20) of (001)- and (221)-cuts for counterpropagating geometry was studied within the frame of slowly varying amplitude approximation. Electrooptic, photoelastic, piezoelectric, self-diffraction effects and optical activity were taken into account.

The mechanism and properties of laser hardening and surfacing of constructional steels and color aviation alloys are discussed. Laws of formation surfacing layer are investigated at restoration of the worn out steel surfaces. At optimum modes of laser processing essential increase of wear resistance and operational properties of color alloys and steels is revealed, both at them laser hardening and at restoration. It is established, that coupled surfaces of different details have the greatest wear resistance later laser hardening. Laser hardening and surfacing influence laser is investigated at mutual processing coupled surfaces in units of a sliding friction on an example of bearings of sliding in a combination "steel-bronze".

Infrared radiation of the object has a wide spectrum. In this case the laser-pump focusing held to strong deterioration of the transformed image quality. It is descended because in such systems the pumping for transformation of bandwidth polychromatic infrared radiation is used. This pumping is in polar opposition to the transformed radiation: laser pumping is in a certain direction, it is monochromatic and narrow-band.

It was investigated the influence of radiation on structure and optical properties of crystals Cr: Mg₂SiO₄. Chromium ions existing in different valence (Cr²⁺, Cr³⁺, Cr⁴⁺) are active particles of solid tunable wavelength lasers. After electron irradiation chromium ions can change valence with modification of optical properties. It was established that electron irradiation significantly influence upon local structure of cat ions in octahedral oxygen encirclement.

Basic parameters defining methodology of radiation transformation at a frequency in noncentrosymmetrical crystals (methodology of collinear synchronism direction, of effective nonlinearity d_eff coefficient and quality parameter β, of angular and spectral width of synchronism angles of regular and irregular rays drift) is presented. On the basis of this methodology a block-scheme was worked out and a Delphi language programme for the above-mentioned parameters calculation was written. The programme is quite speedy and operative and makes it possible to perform autoscaling. With the help of the described and developed programme one can calculate the basic radiation transformation parameters at a frequency for nonlinear cyrstals of any class of symmetry at the interaction of waves both with different (ω₁≠ω₂), and with equal frequencies (ω₁=ω₂).

Pictures of central part of photorefractive light scattering on crystal LiNbO₃:Fe (0,3 %) under frequent preliminary irradiation (P=1-2 mW, λ=0,6328 μm) and consequent thermal annealing during 30 minutes at temperature 200° C are received. It is considered that crystals of niobate of lithium experience thermal fatigue effect at frequentative irradiation and at the subsequent annealing.

The behavior of dispersions of guadrature components of the signal field depending on the correlation of these components (and on parameters of high field, if any) is analyzed.

In the paper is considered possibility of changing image intensity by electric field. In anisotropy crystals it is possible to observe conoscopic figures. Dark cross is observed in teh center of figure if electric field in crystal is absent. The angle size of central dark area is approximately 1 degree. When electric field is enclosed to crystal it becomes biaxial. In this case conoscopic figure have light area in the central part. If image is placed in a central part of the figure then it is not visible when electric field is absent. And image becomes visible when electric field is not equal to zero.

Now at obtaining nanostructures on surfaces of various materials the laser radiation is actively used. In particular, in paper [1] the processes by surface segregation of atoms Cr on a surface SiO₂ under effect of impulses laser radiation are explored, detected in these conditions by the authors new phase Cr in cermet SiO/Cr represent practical interest for creation of devices of optical record of the information. At a laser, ablation of carbon it is revealed forming one-wall nanotubes with the sizes having practical value, the influence to this process inclusion of an electric field is explored also, that called effective derivation carbon cobweb in the macroscopic sizes [2]. In the present message, the interaction of laser radiation with mineral yields as ultra dispersible gold and zirconium of a containing mineral concentrate explored.

A nonlinear wave theory that describes the parametric interaction of the Raman scattering component in an external resonator in a disspipative medium at the phase mismatch in the constant-intensity approximation is presented. This approximation takes into account the reverse reaction of the Stokes component on the exciting wave phase. It is shown that the conversion efficiency can be considerably increased by the choice of the resonator geometry. The high Stokes conversion efficiency is obtained under resonance phase condition. By a judicious choice of the parameters of the problem (phase mismatch, nonlinear length, mirror reflectivity coefficients, pump and anti-Stokes component intensities, absorptions of the interacting waves) the further increase in efficiency of the Stokes component can be achieved. The model is useful for optimization of parametric frequency conversion in the external resonator, and may be applied to different types of nonlinear interaction within the optical resonator.

As it is known the optical Kerr's effect changes cubic medium refraction index and in a nonlinear ring interferometer (NRI) causes to generation of optical structures and chaos. Besides in nonlinear media enough high emission power stimulates a multiphoton process. For example in a cubic medium three-photon absorption is possible. The process in a ring interferometer containing Kerr's medium through which the two-frequency light field is propagated are considered. The influence of mulitiphoton processes to dynamics of nonlinear phase shift in Kerr's medium is investigated. The mathematical model is constructed as differential partial equation, ordinary differential equation, discrete map. Maps of Lyapunov's characteristic exponents as functions of the interferometer and light field parameters are constructed. The influence of these parameters to possibility of determined chaos is discussed. It is shown that the act of three-photons absorption (N=3) produces an amplification of nonlinear effects in NRI due to generation of the third harmonics. And the position of the obrder of nonlinearity is determined by a value K_{b0 s} which is proportional to [2β_bl(N-1)]^-1/(N-1), where l is length of the medium, β_b is a measure of three harmonics generation productivity.

Nonlinear ring interferometer (NRI) is an open passive optical system. Occurence of various steady spatial structures nad dynamic chaos in cross-section of the laser beam propagating through the NRI feed-back circuit under certain conditions is possible. Therefore investigation of various NRI models is perspective with a view of their application in devices of the optical information processing and the hidden transmission of the information. The NRI can make element basis of the devices of the continual logic. Implemented numerical experiments are based on the model of processes in nonlinear ring interferometer with Kerr's nonlinearity in the context of optical cryptosystem development. Chaotic regimes area of Lyapunov's exponent's map portion was suggested to be the integral quantitative characteristic of the whole map. It was proposed to construct the distributions of certain type attractor's quantity depending on model's parameters. Influence of two-frequency input radiation spectrum on bifurcation behavior in the model of ring resonator (interferometer) with restriction of nonlinearity is studied. A bifurcation diagrams in various planes of model parameters are under construction and the degree of influence of these parameters to configuration of (un)steady states of the interferometer functioning is studied.

Optical scheme of three-channel nonlinear fiber-optic lightguide interferometer (NFOLI) is developed. The base of mathematical model of processes in NFOLI is two ordinary differential equations describing dynamics of nonlinear phase shift of light field in the core and in the facing of optical fiber. Phase portraits and Fourier spectrum are constructed. It is obvious that under various parameters in the model regimes of static state, periodical oscillations and deterministic chaos are possible. The optical scheme of three-channel nonlinear optical fiber interferometer (NFOLI) contains three inputs and three outputs, nonlinear medium (NM), which is single mode step-graded index lightguide doped by HgCdTe. Relaxation time of the material nonlinear acceptability τ=10^-12s, nonlinear refractive index n₂=10^-6 cm²/W. The base of mathematical model of processes in NFOLI (which is constructed in relevant approximations) is two ordinary differential equations describing dynamics of nonlinear phase shift u_1,ne1 of light field in the core and nonlinear phase shift u_2,ne1 in the facing of fiber-optic lightguide. Simulation demonstrates that under various values of nonlinearity coefficient K in the model (1)-(7) regimes of periodical oscillations and deterministic chaos are possible. This means htat NFOLI can be service as a base of optical information security system.

We experimentally investigate propagation of light beams of visible range within waveguide arrays of one-dimensional photorefractive waveguides formed in the Y cut lithium niobate wafers. We demonstrate formation of bright staggered discrete spatial solitons within such an array at simulataneous π out fo phase excitation of two waveguide channels by cw light beam with wavelength of 514,4 nm and total power of 200 μW.

An experimental and theoretical studying of adaptive processing a single-fiber multimode interferometer's signal by a reflection and transmission holograms formed in photorefractive BTO crystal without additional reference beam is presented.

The effect of the periodic object image self-restoration in Talbot's planes was experimentally studied. Comparative investigation of the image parameters in paraxial area and in side lobes of diffraction is made. The images in side lobes have more high resistance against damages of an initial object it is proved. On the basis of these investigations, mechanisms which influence to deterioration of images in paraxial area and in side lobes are offered.

Holographic recording medium on basis of dichromated gelatin layers is example of complex nonlinear system. Layers optical parameters such as diffracted efficiency or modulation transfer function are nonlinear in the time or energy dependence under constant intensity of laser irradiation. To research latent image optical parameter behavior we have to divide our systems to same subsystems, each of them works on own frequency and give the contribution to general dynamics of a system. This paper is devoted to using of wavelet-analysis to reveal frequency - temporary characteristics. Similar analyses allow selecting main parameters of subsystem and to control of systems dynamics in order to achieve certain results.

Advanced achievements in holographic and speckle interferometry, physics of solid-state lasers, digital recording and image processing have created real precondistions for a rising of holographic methods of diagnostics to qualitatively new level. In the present work the general concept of universal holographic system for nondestructive researches in industrial environment is considered and results of tests of some units of this equipment are presented.

Due to the fast improvement of digital sensors the digital holographic particle image velocimetry (DHPIV) becomes a promising measurement technique for the determination of the three dimensional velocity components for standard flow problems. Basically, this technique is based upon correlation and particle tracking methods for the extraction of the velocity information from teh images. If a high-speed digital camera is used, the velocity information from the tracer particles is saved in discrete time steps in form of holograms. Each hologram implicitly contains the information about the 3D volume and accordingbly the location of the tracer particles. Their 3D coordinates can be obtained after numerical reconstruction of the investigated volume from the corresponding hologram. Applying correlation and/or particle tracking methods to the holographic films yield the velocity components of the flow passing through the investigated volume. At present, on of the major problems is the accuracy of the particles depth coordinates determination, which is due to the still relative small resolution of the sensors. This paper aims to analyse the efficiency of existing particles depth coordinates extraction techniques, as well as their combination with known techniques of hologram pre-processing like the zero-order elimination in the in-line setup. Additionally, a novel technique for the extraction of the depth positions of the particles is presented, which improves the accuracy of the particles depth coordinate extraction.

In this paper we present the model of record of 3-dimensional transmission and reflection gratings for 0.3<k<1 (k - exponent of intensity in photopolymerization equations) in photopolymers with a dye sensitizer. The numerical simulation of kinetics of transmission and reflection gratings record in this kind of photopolymers and its diffraction performances for optional value of k and contrast are carried out on the base of the model. The model also takes into consideration the following factors: polymerization and diffusion mechanisms of record, optical absorption, contrast of interference pattern, change of diffusion coefficients during record according polymerization level.

We present an analytical model of dynamics of three spatial harmonics of 2D spatial grating profiles with taking into consideration both record mechanisms (polymerization and components diffusion), absorption, interference pattern contrast. On the base of numerical simulation we examined an influence of these parameters on 2D spatial profile along grating vector and along thickness of a film

In this work the theoretical study of pulse string construction of holographic gratings in photopolymeric materials with light-induced optical attenuation has been carried out. The analytical model describing spatial-temporal transformation of holographic grating field during construction process is developed. The model has a view of recurrence relation and takes into consideration light-induced changing of optical attenuation and diffusion process. The results of numerical simulation on the base of the model are presented and include analysis of record stage, self-amplification stage and whole pulse string construction. The behavior of spatial profile and diffraction characteristics of constructed gratings are estimated with the help of numerical simulation. Fitting experiment and theoretical data has been made. The researched photopolymer was made in Institute of Organic Chemistry of the Siberian Separation of the Russian Academy of Sciences (Novosibirsk).

The intelligent health monitoring systems more and more become a technique for ensuring the health and safety of civil infrastructures and also an important approach for research of the damage accumulation or even disaster evolving characteristics of civil infrastructures, and attracts prodigious research interests and active development interests of scientists and engineers since a great number of civil infrastructures are planning and building each year in mainland China. In this paper, some recent advances on research, development nad implementation of intelligent health monitoring systems for civil infrastructuresin mainland China, especially in Harbin Institute of Technology (HIT), P.R.China. The main contents include smart sensors such as optical fiber Bragg grating (OFBG) and polivinyllidene fluoride (PVDF) sensors, fatigue life gauges, self-sensing mortar and carbon fiber reinforced polymer (CFRP), wireless sensor networks and their implementation in practical infrastructures such as offshore platform structures, hydraulic engineering structures, large span bridges and large space structures. Finally, the relative research projects supported by the national foundation agencies of China are briefly introduced.

Principles and schemes of optical information processing, transmission and storage based on the ultra-short laser impulses' interaction with doped rare-earth ions' crystals are considered. Nonlinear optical effect as a photon echo is discussed. This effect is widely used for the investigation of kinetic processing involving the relaxation of elementary excitations in solids. Possibility of parallel processing of large data arrays in the form of two and three dimensional images and flexibility in controlling data flows are represented. ARchitecture of the various photon echo digital operation, including laser digital vector and matrix-vector multiplication are analyzed. Advantages of optical coherent phenomena for quantum computing are discussed.

FBG strain sensors are more and more accepted in the area of structural health monitoring, especially in civil infrastructures. However, due to the fact that FBG senses both strain and temperature simultaneously. And moreover the wavelength shift induced by 1°C is almost equivalent to that induced by 10με. So temperature compensation for FBG strain sensors of long-term structural monitoring is indispensable. In this paper, based on the FBG's strain and temperature sensing principles, the techniques of dual FBGs temperature compensation and the environmental temperature compensation are brought forward. The experiment of cement paste curing monitroed by dual FBGs was carried out. And the advantage of the technique of dual FBGs temperature compensation are proved, which is proper for long-term structureal monitoring system for civil infrastructures.

In this paper we report the results of the working out the fiber-optic measuring system. The fiber-optic measuring lines consisting from sensors are described. The reference piezoelectric modulator is used for the control of the workin gpoint of the measuring line. The tomographical problem arising in data processing is solved by the neural network. An efficient algorithm for neural network training is presented.

This paper mainly studies the application of fiber Bragg grating (FBG) in strain monitoring of civil engineering structure. The principle of FBG was illuminated. Static tests of a steel truss instrumented with FBG sensors were done, in order to study whose distinct sensing character and monitor strains of the truss. Then, FBG sensors were instrumented in a cable stayed bridge named Songhua River Bridge located in the Harbin city of China to monitor strains of key structure sections. A number of meaningful results were concluded.

Numerical methods have been applied for the estimation of a hardware error of x-ray methods caused heterogeeous characteristic x-rays. It is received, that this error depends on a corner of reflection, number of planes of reflection and wavelength. Dependences of diffraction line broadening owing to nonmonochromaticity from these parameters are resulted.

The results of atmosphere laser sounding carried out in frame of round the world expedition on the board of sail training ship "Nadezhda" are presented in this work. Nd:YAG laser was operated on wavelength λ=532 nm, energy per Q-switched pulse - 0.18 J, pulse duration - 4 ns. Laser repetition frquency was 10 Hz. Photomultiplies of backscattering signal receiving system operate in photon counting and analogue mode. Spatial resolution in photon counting mode - 240 m, in analogue mode - 6 m. The night dynamics and structure of boundary layers was investigated.

The collisions of electrons with atoms and ions in an external uniform quasi-steady electric field can differ significantly from collisions with an isolated atom even when the external electric field is far below the atomic field. This is explained by the interference and the change in the time the electrons stay in the vicinity of the scattering atom while they are reflected from the potential barrier of the external electric field. In this paper, the differential cross section for excitation of the atom by fast electrons in a electric field of a crystal surface or in the external electric field was calculated using the asymptotes of the wave functions of the final electron states were taken in the form of standing waves (along the external electric field) in the region between the atom nucleus and the reflection point of the electrons and in the form of progressive waves in the region where reflection points were absent. Quantitative study of this cross section was caried out using numerical methods. The differential cross section was calucated using the nonralativistic Born approximation.

The differential cross section for bremsstrahlung during collisions between electrons and a charged particle in an external quasi-uniform and quasi-steady electric field may differ significantly (even when this electric field is far below the atomic field) from that in the absence of an external field. This is explained by the interference of the scattering charged particle while they are reflected from the potential barrier of the external electric field. In this paper, the influence of a electric field of the crystal surface on the bremsstrahlung during collisions between the electrons falling on a potential barrier of this field and a charged particle, when additional interference of the electrons in their initial states appears, was considered. The differential cross section for the bremsstrahlung in this electrid field was calculated using the nonrlativistic Born approximation and the wave functions describe the current density of electrons in an external electric field or the electric field of the crystal surface.

In article the multilevel hierarchical control system is considered. There is a necessity of replacement or updating of elements of the given system periodically. For realization of an estimation of expediency of such actions the mathematical model of an adaptive hierarchical control system is developed. This model is a system of the kinetic differential equations of the second sort with saturation. Researches of dynamics of the answer of a control system on external influences such as threats or noise are lead.

The design sophistication of optical instruments with low level instrumental (including diffraction) scattered illumination is very interesting not only for solar asrophysics. The construction of a laboratory installation for measuring intensity of a diffractio-swcattered illumination in a shadow of darkening system of a coronagraph with an exterior eclipse surveyed is described. The method of measuring, permitting to minimize influecing of a light, scattered from interior surfaces of installation is offered. Measuring of intensity of a diffraction-scattered illumination in a shadow of the single disk with different lateral views of edge is conducted. From the obtained experimental data follows that the change of the shape of scattering edge of exterior darkening system can essentially reduce intensity of a diffraction-scattered illumination in the field of an entrance pupil of an external occulted coronagraph.

The opportunity of diagnostics and defects type the analysis in the optical fiber communication line is examined with the help optical reflectometer with processing a signal on the algorithms based on the radar imagery theory. Organization principles of the reflectometer measurements for detection and identification both local, and the distributed optical fiber defects are developed. Mathematical fiber lines defects models and probable mechanisms of their occurrence are discussed. The data about the real defects arising at fiber-optical communication lines exploitation are discussed too.

One of ways of registration of x-ray radiation is the transformation of energy of x-ray quantums to seen radiation for the account photoluminescence, arising in the semiconductor at absorption of x-ray radiation. In the present report the results of development the express-method of manufacturing of system such as "x-luminofor (ZnS)_x (CdS)_1-x - photoexplorer CdS" are resulted, on the basis of layers of connections A₂B₆, received by a mehtod of chemical pulverization. The system, received by such method, should consume insignificant capacity, have small dimensions and weight, to increase reliability and stability of the target characteristics in a wide dynamic range of intensity and energy of x-ray radiation.

THe seawater flurescence spectra were measured by laser induced fluorescence (LIF) method. ND:YAG laser with frquency-doubled output at 532 nm was used to induce the fluorescence. The laser fluorometer measured the fluorescence spectral distribution in the band from 540 nm to 740 nm. Chlorophyll-a concentration and conventional concentration of dissolved organic matter fluorescence (FDOM) in wavelength range from 560nm to 740nm wer calulated from LIF spectra. The correlation coefficient between chlorophyll-a and FDOM concentrations was calculated in the floating window along ship track. High value coefficient means that FDOM produced by phhytoplankton living on the investigation sea area at the given time interval. Chlorophyll-a-FDOM relationships were described by linear regression. Intercept coefficient is a background FDOM (or FDOM do not produced by phytoplankton living on the investigation sea area in given time interval) and the slope coefficient is FDOM productivity by one μg/l of chlorophyll-a of phytoplankton. The clusters were determined from calculated slope, intercept and correlation coefficients. The clusters correspond to phytoplankton communities and calculating coefficients characterize condition and the evloution stage of these phytoplakton communities.

Influence of pulse duration and focussing mode the first and second harmoics radiation Nd:YAG lasers on shock waves characteristics arising at optical breakdown near to a surface of water was investigated in the present work. The lasers with different parameters of radiation were applied to making the optical breakdwon. The first laser had pulse of duration 4 ns, energy 240 mJ, and wave length of radiation 1064 nm; the second laser had pulse of duration 18 ns, energy 400 mJ, and wave length of radiation 1064 nm; and the third laser had a uplse length 5 ns, energy 180 mJ, and wave length of radiation 532 nm. The laser pulse was focused by the lens (f=70mm) above a surface of a liquid, and then it was directed on surface and under surface of a liquid with the help of the microscrew. For each case, was carried out registration of optical breakdown and arising shock waves by the shadow camera. THe spectral complex "Flame Vision PRO System" with the time resolution about 3 ns was used to analyze the shadow images.

This paper present the results of computer simulations of pattern recognition using LPCC filters, designed for various types of distortions of input images (rotation, change of scale and rotation + change of scale).

A new mode of imaging of ferroelectric domains in the scanning electron microscope (SEM) has been developed. Like the electron beam induced current (EBIC) mode the sample is covered by thin metal electrodes. The electrons with the incrased energy (10-40 keV) penetrate through a thin electrode and stimulate polarization processes in the bulk of the sample. The electric response is read from the circuit between front and back electrodes. The mechanism of the response forming and the problems of the method resolution are discussed.

Experimental method of local thermal diffusivity measurements of inhomogeneously materials and automatically equipment for this is presented. Method is a combination of temperature wave principals and photothermal modulated laser ellipsometry. Application of this method for investigation of local thermal properties of inhomogeneous materials and anisotropy in small simples of metals with submicro- and nanocrystalline structure is shown.

In the present paper the characteristics and opportunities of application of the system of parallel input-output of information from the fiber-optical measuring network into computer are considered. The system consists of two pars: on manframe and several expansion blocks. The first part is internal, is connected directly in the socket of the motherboard of the personal computer. It is designed for buffering system signals and development of cojmands of controlling by the system for input-output of signals into personal computer and signals generation onto expansion blocks. The second part is external, connects to the mainframe by means of cables. It designed for transformation of information from the fiber-optical measuring network into signalsof rthe mainframe and instrument settings adaptation. The analysis of speed of procesing of analog and digital data by system is presented. The possible schemes of use of the system for processing quasistationary and dynamic fields are considered.

In the given article the method of optical information gathering form the fiber-optical measuring network with its subsequent processing is offered. In this method the algorithms of neural-like networks in computation process is introduced. Each sensitive area of the fiber-optical measuring line is associated with the own amplifier. Adjustment of amplifiers gain factors carries out modification of the weighting coefficients of the matrix of connections of the neural netowrk. The training principles to external physical influences are represented. The selection of the type of the neural network for decision of the fiber-optical tomography problem of spatial distribution reconstruction has been considered.

Few mature techniqes to estimate the damage mechanics of cement mortar are available. A new method of damage evolution prediction and model of cement mortar based on acoustic emission is given. The depict damage evolution of cement mortar, rate process analysis and acoustic emission signal amplitude versus hits correlation figure analysis are propose. THe results show the two methods can predict effectively its damage evolution and damage degree. Based on the experimental results, damage factors were defined as the variation value of acoustic emision energy, and the equation of damage evolution and the constitutive equations presented by acoustic emission parameters are derived. The evolution equation can be used to make dynamic assessment and estimation of damage degrees, which is useful for the study of th quantitative measurement structural damage factors.

A phased array ultrasonic inspection system is being developed ot obtain electronically scanned ultrasonic images of the inside of steel structures for nondestructive evaluation. This phased array ultrasonic inspection system is made up of computer, scanner, motion controller, motor driver, ultrasonic emission, receiving & delay circuit, high speed data acquisition circuit and ultrasonic phased array transducer, this system has the functions of controlling ultrasonic transmission and receiving, controlling sound wave steering and focusing, controlling scanner moving, revceiving position information and flaw information, restructuring flaw image. Experimental tests were done on a steel testing block with side-drilled holes to simulate defects. The side-drilled holes could be detected and their diameters could be estimated from B-scan image, and B-scan image could show the location of side drilled holes clearly and does not have any ghost image.

The application of adhered FBG strain sensor is affected by interface strain transfer and error modification. In his paper, firstly, based on the characterstics of forces and damage, the fundamental hupotheses are given, and the general expression of interface transferring mechanism is derived. After that, united form of the characteristic value-λ for the general equation is geven for the multi-layer coatings. Finally, according to the error-modified equation of adhered FBG sensor, the relationships the error rate η against the shear modulus and the thckness of the glue are given. With regard to the glue applied in engineering (thickness is from 4mm to 60mm, shear modulus is from 30MPa to 200MPa), the error rate η is about 5~10%, and the correction coefficient k is about 1.05~1.11. Hence, the error modification must be considered when adhered FBG strain sensors are used in civil engineering.

A fiber optic method of ingineering structures operation safety remote monitoring has been worked up. The sensitive element's principle of operation rests on a free hanging shutter partly blocking the light flux when the sensor tilts, which brings about changing of the senosr's output signal. The threshold sensitivity of the sensor amounts to 0.005 deg; dynamic range - 90 dB; measuring angle range - 0 deg. 5 deg. The trsnsducer can be used in precision measuring systems for monitoring absolute inclination of engineering construction structural components.

The article presents optical receivers developed on the basis of two-beam laser interferometer for registration of ultrasonic signals of bulk and surface waves in solid media in the range of frequencies up to 1000 MHz. It is shown, that laser interferometer is an "absolute" receiver, i.e. not demanding calibration for measurement of displacement inan acoustic wave. The rational design of the interferometric head is described. Block diagrams of measurements are given. Characteristics of optical receivers are shown. Specific applications of optical receiveers in various installations are described. Experience of application of semi-conductor lasers in the optical receiver is outlined.

In coupled Hopfield neural networks, in which different patterns are stored in each network, the associative memor problem is investigated. It has been shown numerically by several authors that in coupled two chaotic neural netowrks, where different patterns are stored, one network can retrieve that pattern stored in other network. In the Hopfield theory a stored pattern corresponds always to an attractor in the dynamical sense. The retrieval of the pattern stored in other network means that the state of Netowrk A approaches no the attractor of Netowrk A but the attractor of Netowrk B by coupling Network A with B. In this paper, we study this problem in an analytic approach. It is shown that the final pattern of the each network is classified into 4 types according to the initial condition and the connection constant. By introducing the energy function of the total system the problem is also investigated from a viewpoint of energy. We propose the system, in which many Hopfield networks are connected, and its application is discussed.

We have experimentally studied the low-temperature photoluminescence (PL) kinetics in type II GaAs/AlAs superlattices under the influence of an electric field. We have found that the application of electric field leads to an increase in the PL intensity of free exciton line and e-hh PL line, while the PL intensity of lines of localized excitons and phonon replicas do not increase. Then the acceleration of PL kinetics of the no-phonon and phonon-assisted excitonic lines starts after some decay with respect to the appearance of the SAW electric field at the photogeneration point. We conclude that (1) the origin for the rise of the PL intensity of free exciton and e-hh lines is carriers ejected from the localized states by the electric field; (2) the PL intensity of localized excitonic line is not increases because the lateral electric field prevents localization; (3) the acceleration of PL kinetics of no-phonon and phonon-assisted lines is due to an increase of the X_Z-exciton recombination probability that results from impact with the electrons transferred to the Xxy levels by electric field.

In a global neural network, which consists of many connected local neural networks the mechanism of memory and the information flow are discussed. One of local neural networks in the global network is connected with an input network, which provides some pattern (or some information) to the global network from outside. We assume the nearest-neighbor coupling between local networks in the global netowrk. The local netowrk can exchange the pattern or information among nearest-neighbor local networks in the global network. The local netowrk can exchange the pattern or information among nearest-neighbor local netowrks and the patterns can propagate in the global system. The propagation of the pattern persists even after the connection between the input network and one of local networks in the global network was decoupled. For the appropriate nearest-neighbor coupling the propagated pattern generates a global pattern and it does not disappear. We study the role of the local coupling in the genesis of a global pattern and in memorization of the information inputted from the outside.

Last years MEMS (Micro Electro Mechanical Systems) technology is fast developing area of engineering. Mechanical constants of the materials used in deveices created on this technology depend on the technological processes at their production. Therefore the great importance to a quality monitoring of parameters of MEMS-devices is given. There is a necessity for creation of setups for non-invasively measuring of objects microshiftings to within tens nanometers. The pupose of the present work is application of holographic interferometry with increased sensitivity methods, based on using of the nonlinear effects, for measurement of MEMS-devices elements microshiftings. The proposed technique consists of several steps. On first step microshiftings of objects are recorded on the couble exposure hologram. Further the reconstruction image is photographed on another plate. This plate can be presumed to be an equivalent of a nonlinear hologram. Finally at illumination of this plate one can observed the interferention of higher harmonics. Using the obtained interferogram it is possible to determine of test objects microshiftings with the increased sensitivity. After measurement of microshiftings of special test objets under known loadings it is possible to calculate values of material elastic constants. Features of the method proposed in the present work consist in its comparative simplicity, multifunctionality and high sensitivity to measurement of microshiftings (up to 1/16 of a wavelength of light used at illumination). Theoretical calculations and preliminary experiment results have demonstrated that by means of such mehtod it is possible to measure microshiftings of diffusely reflecting objets with submicron sensitivity.

The phenomenon of four-ray refraction and dispersion in crystals plumbum molibdate (PbMoO4) was considered. Results of calculation of dispersion four-ray refraction and dependences of corners of reflection on corners of falling in a wide interval were considered.

A new kind of FRP (Fiber Reinforced Polymer) packaged FBG temperature sensor is developed, and its installation technique has also been studied. The experimental results show that this kind of sensor has good linearity, high accuracy. and high sensitivity. During the construction of the Third Nanjing Yangtze Bridge they were applied to monitor the temperature distribution of the mass concrete. The monitoring results of temperature distribution and its changes with time, environmental temperature, setting retarder, and cooling water agree well with that from experience and qualitative analysis. The practical application shows that the FRY-packaged FBG temperature sensors are proper to be used in temperature monitoring in mass concrete structures.

The principles of design and theoretical research of mirror waveguide optical delay line are represented. The results of computer simulation are considered. The practical realizations and measurement properties of this device are describe. Performance results are provided showing that the delay 3*10^-8 sec may be reach.

Issues concerning the structure ofsoil after compaction are important for achieving the stability ofthe soil structure itself. In this study, structure and density of soil containing sand or gravel after compaction are examined, keeping in mind the difference between the actual density measurements and theoretical values derived by the Walker and Holtzs method. Compaction experiments were performed for a mixture ofgravel or sand and finegrained fractions. Based on the results of these experiments, basic structures I and II were configured, which were used to present formulae for calculating mixing ratio of these structures within compacted soil. In addition, water immersion and peneiration tests were performed using specimens with different thegrained fractions ratios. These experiments verified that the structures of compacted soil containing gravel or sand and finegrained fractions were ofthe mixture ofthe basic structures I and II above, and the ratio ofthese basic structures within the soil are determined by the mixing ratio between gravel or sand and finegrained fractions, and furtheimore by the densith of each stnicture when compacted.

Ultrashort channel GaAs metal semiconductor field effect transistors were fabricated with gate lengths ranging from 30 nm to 1 05 nm, by electron beam lithography, in order to examine the scaling characteristics of transconductance. For gate lengths in sub-100 nanometer range, where gradual channel approximation is no longer valid, it was observed that the transconductance varies with a variety of small-dimension-related, nonequilibrium electron dynamics phenomena such as gate fringing effect, electron velocity overshoot, and short channel tunneling. Short channel tunneling was suggested experimentally for the first time to explain the degradation of transistor performance, overriding an enhancement due to electron velocity overshoot for a gate length smaller than the average inelastic mean free path of an electron.

Nonlinear optical sulfides and selenides transparent in wide spectral range are of paramount importance for frequency conversion in JR range. The combination of chemical bond lengths between atoms in crystal lattice is a key factor that defines the structure and properties of the material. In this study the comparative analysis has been produced for chemical bonding in binary noncentrosymmetric sulfides (~3OO) and selenides (~100). It is shown that noncentrosymmetric binary sulfides or selenides are positioned on the limited field on the plane ofthe chemical bond lengths. The field is covered by two partly intersecting ellipses. The most efficient piezoelectric, electrooptic and nonlinear optical crystals concentrate near the boundary and inside crossing part of the ellipses. The dependency of nonlinear optical susceptibility χ⁽²⁾ on the characteristic chemical bond length is non-monotonic in both sulfides and selenides and can be divided in several segments, which contain compounds with different bond values and coordination number. The combinations of the cations in sulfide and selenide crystals promising for high χ⁽²⁾ and transparence have been evaluated.

By using Surface-Enhanced Raman Scattering, We studied the orientation of liquid crystal 5CB absorbed on nano-roughened Ag and Au Electrodes. Our results firstly suggest that the orientation of LC 5CB absorbed on nano-roughened Ag electrode is different from that of Au electrode. This implies that the interaction between LC 5CB and Ag is different from the interaction between LC 5CB and Au. The conclusion is that the orientation of LC 5CB absorbed on nano-roughened Ag electrode is perpendicular, and the orientaiton of LC 5CB absorbed on nano-roughened Au electrode is more complicated, including parallel, perpendicular and tilted.

Continuous very thin (2.5-3.0 nm) and thin (16-18 nm) ytterbium suicide films with some pinhole density (3•10⁷- 1•10⁸ cm^-2) have been formed on Si(111) by solid phase epitaxy (SPE) and reactive deposition epitaxy (RDE) growth methods on templates. The stoichiometric ytterbium suicide (YbSi₂) formation has shown in SPE grown films by AES and EELS data. Very thin Yb suicide films grown by RDE method had the silicon enrichment in YbSi₂ suicide composition. The analysis of LEED data and AFM imaging has shown that ytterbium suicide films had non-oriented blocks with the polycrystalline structure. The analysis of scanning region length dependencies of the root mean square roughness deviation (σ_R(L)) for grown suicide films has shown that the formation of ytterbium suicide in SPE and RDE growth methods is determined by the surface diffusion of Yb atoms during the three-dimensional growth process. Optical functions (n, k, α, ε₁, ε₂, Im ε₁^-1, n_eff, ε_eff) of ytterbium silicide films grown on Si(1 1 1) have been calculated from transmittance and reflectance spectra in the energy range of 0.1-6.2 eV. Two nearly discrete absorption bands have been observed in the electronic structure of Yb silicide films with different composition, which connected with interband transitions on divalent and trivalent Yb states. It was established that the reflection coefficient minimum in R-spectra at energies higher 4.2 eV corresponds to the state density minimum in Yb suicide between divalent and trivalent Yb states. It was shown from optical data that Yb silicide films have the semi-metallic properties with low state densities at energies less 0.4 eV and high state densities at 0.5-2.5 eV.

β-BaB₂O₄ (BBO) crystals are among the most effective nonlinear optical materials used for frequency conversion. At the same time, some important physical properties of BBO are less studied and its potential applications are not clear yet. In this work we studied the optical and acoustical properties of crystals produced by improved top-seeded solution growth (TSSG) method. Using particular chemicals for molten solution synthesis and periodical adding ofproper compounds into the melt allowed us to control the degree of boron-oxygen polycondensation in the zone of seeding and crystal growth. Hence, growing BBO single crystals contained little or no melt inclusions and low-angle structural boundaries. Optimization of cooling conditions of grown crystals eliminated microscale light-scattering centers. Transmission spectra in mid-IR range show the system of absorption lines related to the presence of OH-groups in crystal lattice. Sound velocity measurements have been conducted using interference acousto-optic technique for longitudinal crystallographic directions. It has been shown that the crystals are characterized by higher stiffness tensor components compared with those reported for BBO grown by traditional TSSG method. The effect appears to be the result of BBO structural quality owing to the progress in crystal growth.

Processes of β-FeSi₂ nanosize islands growth on Si(111)7x7 surface and Si(111)-Cr surface phases (SP) and silicon overgrowth atop β-FeSi₂ nanosize islands have been studied by LEED, in situ Hall temperature measurements and ex situ AFM and optical spectrscopy methods. It was established, that Si(111)7x7-Cr surface phase appears the influence on β-FeSi₂ island orientation and crystalline structure, but island density does not change as compared with Si(111)7x7 surface. It was shown that Si(111)√3x√3/30°-Cr SP results in reduction of iron disilicide island density and their repeated nucleation on the free modified silicon surface. The optimal growth temperature (800 °C) for molecular beam epitaxy (MBE) of silicon layer atop of β-FeSi₂ nanosize islands on different substrate has been determined. It was revealed, that iron disilicide clusters, grown on Si(111)7x7-Cr surface phase, appear the minimal influence on crystal structure of the silicon layer. It was observed the closed concurrence of electric parameters of silicon with buried iron disilicide clusters and atomically clean silicon that testifies to the minimal carrier scattering on these clusters and can confirm them epitaxial burying in the silicon crystal lattice. From optical spectrscopy data two direct interband transitions at 0.75 eV and 1.10 eV were observed in silcon samples with buried β-FeSi₂ nanosize clusters.

Implantation of high energy He and H ions into Si creates strongly disturbed buried areas in Si:H,He. He- and H-filled bubbles are produced. Formation of microcavities in H, He-implanted Si is a one of creation methods of porous silicon which is perspective material ofoptoelectronics. Annealing at high temperature causes the He to diffuse out. Besides. He atoms at HT-HP treatment of Si:H,He influence strongly on hydrogen out-diffusion. To explain experimental facts we used the density functional theory and ab initio pseudopotentials. Calculations show that single helium atoms accumulate in divacancies at absence of external pressure. Helium stimulates formation of voids in silicon and simultaneously fills them. Leaving silicon interstitial sites for divacancies, H2 molecules dissociate up and passivate silicon dangling bonds with the energy profit of 1.6 eV. Presence of two He atoms per divacancy reduces this profit by 0.1 eV. The 5 GPa pressure decreases this energy additionally by 0.4 eV and makes hydrogen in silicon less bonded and more mobile in accordance with experimental data.

The structural defects had been found on the surface of high-doped H:LiNbO₃ waveguide layers produced on X-cut LiNbO₃ substrates in pure benzoic acid at T ≥ 185°C during t>1 h. The defects are similar to "scratches" but oriented definitely in reference to Z crystal axis. Measured 3D and 2D profiles show the defects outspreading above the substrate surface at a height ~4.4-9.0 nm, having width a half height ~1.7 μm and length from ~2 μm up to 100-300 rim. Areas, where the density of these defects is increased, as a rule, are limited by scratch traces from lapping and polishing. Preliminary annealing of the substrates or Ti in-diffusion at temperature ~1000 °C before PE avoid the defect formation and the substrate roughness is not changed by proton exchange.

Photographic properties of polyvinyl alcohol (PVA)-ZnO/TiO₂ compositions sensitized by BiCl₃ were investigated in a process with direct blackening. These properties in general are similar to those of earlier investigated compositions sensitized by lead acetate (PbAc). Direct blackening in system with BiCl₃ is more resistant to moisture.

Development of methods for generating of laser beams with predetermined values of intensity and angular momentum distributions is a challenge of great interest for various laser technologies including laser manipulation by microscopic objects. The suggested method oftransformation of laser radiation to complex structure modes in build-up beam rotator interferometer has been theoretically evolved and experimentally tested. Its main advantage over the others is that the method doesn't require complex diffractive optical elements to be used. Experiments were performed using tunable (adjustable) diode laser and interferometer formed by three mirrors. The beam rotation has been achieved by Dove prism inserted into the interferometer. The evolution of the transformed beam was observed with alternation of the prism rotation angle and the injection current of the laser diode.

Electrodynamic of thermo-EMF models in sandwich structure metal-ferroelectric-metal is analysed.

Morphology, optical properties, crystal and electronic structure of monocrystal silicon after plasma processing, depending on initial voltage of magnetoplasma compressor (MPC), have been studied. It was shown that periodic surface structures are formed on silicon only in the short range ofinitial MPC voltages (2.8-3.2 kV), but at higher initial voltages (3.4-3.6 kV) the formation of "crater" and carrying out of the part of material on its periphery till the moment of crystallization is observed without the formation of surface structures. The decrease of the silicon lattice constant has been observed after plasma processing at all initial voltages that correlates with the decrease of band-gap energy by data of optical spectroscopy. Changes in crystal lattice and electronic structure of silicon modified by compression plasma flow have confirmed by red shift of 4.5 eV peak in reflectance spectra and decrease of its amplitude.

The technology of solid-phase growth of nanosize islands of magnesium suicide on Si (111) 7x7 with narrow distributions of lateral size and height (60 - 80 and 5 - 7 nanometers, respectively) and density of up to 2x 10⁹ sm^-2 is proposed. A 20-50 nm thick Si layer has been grown upon these islands. Basing on the data of AES, EELS, AFM and JR spectroscopy, a conclusion is made that the Mg₂Si islands remain in depth of the Si layer. The suggestion is made that sizes, density and crystal structure of the buried magnesium suicide clusters preserves. It is shown, that the system of three as-grown layers of buried clusters has smoother surface than the one layer system. The contribution of the Mg₂Si clusters into the dielectric function is observed at the energy 0.8-1.2 eV, it is maximal if the clusters are localized on the silicon surface. It is shown, that with increase of the number of Mg₂Si cluster layers their contribution increases into the effective number of electrons per a unit cell and effective dielectric function of the sample.

A technology of solid-phase growth of Mg₂Si thin films from Mg and Si layers on a pre-fabricated template layer of Mg₂Si islands on Si (111) has been developed. The optimum temperature (T=550° C) for growth of epitaxial Mg₂Si films on Si (111) has been found. It has been shown from optical spectroscopy data that Mg₂Si epitaxial film has a direct fundamental transition with the energy of 0.75-0.76 eV with small combined density of states. It represents transition of small number of valence electrons into Mg-Si bonding states in the conductance band. The strong absorption range (1.9-6.2 eV) corresponds to transitions from bonding to anti-bonding states.

The method of Differential Reflection Spectroscopy (DRS) have been applied to study thin iron films during the process of growth on Si (111) or Si(100) surfaces at room temperature. Some details on the Dynamic Standard method in DRS method are presented. Magnetic properties of as-grown films have been demonstrated by the SMOKE method. Dependence ofdielectric functions of the films on the deposit amount is given.

It is clarified that the absolute instability corresponding to the terahertz oscillation occurs at the high electron-hole plasma density in InSb. The computer analysis of the dispersion equation for longitudinal waves in the solid state plasma in InSb is performed for arbitrary orientations of the carrier drift velocity relative to the external magnetic field. The oscillation frequencies of terahertz waves are increased with the electron-hole plasma density, the external magnetic field and the angle θ. (θ is an angle between the carrier drift velocity and the external magnetic field) The maximum frequency of the terahertz waves is 5.0 THz at the electron-hole density of 1 X 10¹⁹ cm^-3 and the transverse magnetic field of 20 kG. In this case the wavelength λ is 16 nm and the phase velocity u_p is 0.8 X 10⁷ cm/sec.