Infrared degenerate four-wave mixing spectroscopy (IR-DFWM) has been employed to study the molecules acetylene (C₂H₂), ammonia (NH₃), methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O) in a cell under equilibrium conditions and cooled in free jet expansions. For methane at room temperature the detection limit was 2 X 10¹² molecules per cm³ and quantum state, enabling the detection of trace species with a spatial resolution of 1 mm² X 30 mm. In an attempt to study transitions in the v₁ + v₃ and 2v₂ + v₃ combination bands of CO₂ or N₂O, it was not possible to observe any DFWM signal. Instead a surprisingly strong, backward and forward directed emission was found which could not be attributed to the DFWM process. Our investigations lead to the conclusion that the emission can be explained by stimulated Raman scattering, resonantly enhanced by transitions to the combination levels v₁ + v₃ and 2v₂ + v₃. This process seems to suppress the generation of DFWM signal.

We applied time resolved light diffraction from electrostrictive gratings to measure non-intrusively gas compositions and temperatures. The infrared radiation of a pulsed Nd:YAG laser generates a spatially periodic density grating that oscillates in time and the beam of a continuous- wave laser or a train of pulses provided by an external cavity is used to read it out. The oscillation period of the grating diffraction efficiency depends on the sound velocity in the medium. If the gas composition is known the measurement of the sound velocity allows to deduce the temperature. We evaluated this novel technique in an open tube furnace for temperatures in air up to about 1400 K. On the other hand, if the temperature is known, concentrations in isothermal binary mixtures can be determined by the laser-induced grating technique. Measurements were performed in methane/nitrogen and hydrogen/nitrogen mixtures.

An experimental technique based on coherent one-dimensional four-wave mixing (FWM) with hyper-Raman resonances has been developed for line-by-line imaging of the atomic distribution of excited atoms in a low-temperature plasma of optical breakdown. Investigations of the influence of phase mismatch and one-photon absorption on FWM in a laser-produced plasma demonstrates that FWM images of atomic spatial distributions free of distortions due to phase mismatch and absorption can be obtained for certain stages of plasma expansion. The sensitivity and spatial resolution of FWM imaging of atoms in a laser-produced plasma are estimated.

Dual-broadband coherent anti-Stokes Raman spectroscopy (CARS) of the Q-branch of H₂ has been employed for thermometry in a laboratory atmospheric pressure hydrogen-oxygen flame. The aim was to investigate the applicability of the technique for single-shot temperature evaluation, to estimate its sensitivity and to analyze the accuracy of the measurements. The results are presented of single-shot temperature mapping of the flame in the temperature range of 700 - 3200 K. The achieved accuracy of single-shot measurements was 3 - 5%.

This study was made for measurement of hydrogen concentration in gas mixtures by coherent anti-Stokes Raman spectroscopy (CARS) with the aim of devising a technique for the detection of hydrogen-released from metals and insulating liquids exposed to a variety of external agencies. It has been found experimentally that under the fixed parameters of resonance biharmonic laser pump (BLP) the CARS signal of low constant hydrogen density essentially depends on the pressure of buffer gas. The obtained results are attributable to motional narrowing and broadening of the Doppler line of the Q₀₁(1) transition of H₂ in the gas mixture.

The data on water and water solutions four-photon spectroscopy are presented. In the low frequency spectral band (0 - 100 cm^-1) the four-photon spectra of intermolecular and collective vibrations of water molecules are predicted theoretically and observed experimentally. Anisotropy relaxation processes in associated liquids can be studied effectively with the use of four-photon polarization spectroscopy. In contrast to spontaneous Rayleigh wing scattering, the four-photon signal contains an interference of Kerr, Rayleigh, and Brillouin nonlinearities, which deforms specifically the detected spectrum. This fact allows mutual calibration of cubic nonlinearities related to above mentioned processes.

The instantaneous heating of distilled water by Nd:YAG laser second harmonic pulses irradiation have been found out experimentally. The measurements have been carried out in backscattering scheme and experimental Raman spectra of water molecules stretching vibrations band were approximated by Lorentz or Gauss contour by the least squares technique. The temperature shift coefficient of both the envelope contour center is (1.0 plus or minus 0.1)cm^-1 and laster pulse repetition rate temperature shifts are 2 degrees/Hz for water and 4 degrees/Hz for ice. Temperature anomalies in the approximated contour width and frequency are revealed in distilled water near the phase transition points 4, 36 and 75 degrees Celsius.

An experimental technique for measuring dc fields in plasmas using coherent four-wave mixing (FWM) is proposed and theoretically substantiated. The influence of plasma microfields on the intensity and polarization of the FWM signal is analyzed.

We studied intensity of the Stokes component of the four-wave scattering by coherently excited phonon polaritons as a function of phase mismatches. Experiments in homogeneous LiIO₃, differently doped LiNbO₃:Mg, and periodically poled Nd:Mg:LiNbO₃ crystals are discussed from the scope of the conventional model. We found sufficient discrepancies between the model predictions and observed linewidths in LiNbO₃ crystals. The general expressions for the four-wave signal dependence from phase mismatches in periodically-poled crystals and in spatially-limited crystal areas are derived.

A coexistence of electric and magnetic order in hexagonal YMnO₃ gives rise to an unusual nonlinear optical polarization P(2(omega) ) which contains two contributions defined by the two order parameters. The two contributions overlap over a wide frequency range thus opening up new possibilities to study the electronic structure of crystals. The magnitude and phase of P(2(omega) ) can be changed by varying the ratio between the two contributions. We show that 180 degree ferroelectric and antiferromagnetic domains, which are indistinguishable in linear optics, can be visualized with a high contrast using the second harmonic light.

New experimental technique for near-field observation of second-harmonic generation is discussed. This technique gives the unique possibility for the investigation of local optical nonlinear processes with subwavelength resolution and will be useful for the characterization of materials as well as for fabrication and utilization of optical nonlinear devices at nanometer scale. Peculiarities of optical nonlinear processes in near-field region have been studied. The difference in the mechanisms of second-harmonic generation for different polarizations of excitation light has been demonstrated for rough metal surfaces. The dependence of second-harmonic intensity on tip-surface distance has been examined verifying the presence of strong evanescent SH field components. The technique has been applied for characterization of optical nonlinear crystals (LiNbO₃ and KDP), ferromagnetic and ferroelectric materials. The spatial resolution of the microscope in the SH light collection mode has been determined to be better than 150 nm.

New method of time-resolved optical study with high spatial resolution using femtosecond laser pulses focused on (metallic) tip of scanning probe microscope is considered. The system may be incorporated, e.g., into the set for pump- supercontinuum probe studies, i.e. the method can give high time, spatial and spectral resolution simultaneously. The last occur to be compatible with uncertainty principle. Excitation of eigenmodes (plasma oscillations) in the system tip- substrate and their field localized near the tip are analyzed. Their excitation by an external electromagnetic field are considered in a system tip-substrate. Drastic amplification of the effective field in the area of nanometer scale under the tip of a scanning tunneling microscope or an atomic force microscope can be used to study linear and nonlinear optical properties of nanostructures with ultrahigh spatial resolution, as well, as for nanolithography.

An introduction to elements of diffraction theory of coherent scattering of vector waves for size & velocity measurements is proposed to discuss. In traditional approach, a square-law detection is to observe beating (fluctuation) in optical signal consists of two components: scattered and not-scattered scalar waves. The basis of proposed analysis is to consider mixing on a photodetector of two coherent vector waves with variable states of their vectors of polarization. Vectorial optical signal for spectral analysis is considered in framework of Fraunhofer diffraction for scattering of two plane vector waves by a single particle in case of periodical modulation of an angle of vector polarization described by Jones vector. The formalism of Jones matrix is proposed to describe coherent scattering by a distribution of particles to control their sizes and velocities. A portable spectrometer for Coherent Light Beating Spectroscopy (CLBS) for size & motility application in biology is described.

Phonon coherent excitation can be ascribed to an impulsive or a spectral mechanism, when dealing with ultrashort pulses. Contrary behaviors, that depend on wave vector matching conditions, are revealed and selected by a specific detection arrangement. A spectral analysis of the signal confirms this findings.

The circular dichroism (CD) effect is predicted in a specific case of a two-color ionization of atoms, due to interfering a dc field-induced resonance two-photon ionization by electromagnetic radiation with frequency (omega) and the one- photon ionization by the wave with frequency 2(omega) . The maximum degree of CD may be observed in the range of fields where the probability for the dc field-induced two-photon ionization becomes comparable with that of the single-photon process and exceeds essentially the field-free two-photon ionization probability. The effect is sensitive to the relative phase between the two ac field components. The atomic parameters for this effect in alkali atoms are calculated. The range of fields is determined, for which the dichroism becomes observable. The use of the effect to control the branching ratio and the relative phase of the two radiations is discussed.

We report about an experimental observation of alignment induced resonance in Doppler free spectrum of D₂ absorption line of ⁸⁷Rb ((lambda) equals 780 nm). The resonance appeared as a peak of absorption instead of transmission at the position of crossover resonance between the 5S_1/2(F equals 1) yields 5P_3/2(F' equals 0) and the 5S_1/2(F equals 1) yields 5P_3/2(F' equals 1) transitions.

A new group of electrons in the naphthalene ZEKE PFI spectrum has been observed in the energy range 70000 - 72000 cm^-1 by the one-color two-step laser excitation technique. It can be assigned to the field ionization of the high n Rydberg states converging to the first electron-excited ionic state of naphthalene. The lifetimes of the superexcited Rydberg states with the energy excess (above the first ionization energy) up to 1 eV are about 1 microsecond. The improved value of the second adiabatic ionization potential is 71823 plus or minus 30 cm^-1 (8.904 plus or minus 0.004 eV).

We propose a contactless technique of modulation spectroscopy for semiconductors which is based on the AC electric field effect on the probing light beam reflection. This technique allows one to investigate the distribution of both built-in and induced electric fields as well as the electron-hole interaction effects in various layers of the semiconductor structure. The measured spectra are explained by a combination of the interband transitions in the high-field (Franz-Keldysh effect) and low-field regimes, the transitions via exciton states and the temperature effect. The model is developed which allows one to describe quantitatively the spectra observed on the modulation-doped heterostructures GaAs/AlGaAs.

The effect of fluorescence saturation under laser pulsed excitation appears as a non-linear response of emission signal versus intensity of excitation. The saturation becomes important when the rate of molecular excitation exceeds the rate of their deactivation. Typically the effect is noticeable when excitation photon flux ((rho) ) exceeds 10²³ . . . 10²⁴ cm^-2s^-1. We present the theory of fluorescence saturation under laser pulsed excitation for both quasi-stationary and non-stationary cases, as well as the experimental study on fluorescence saturation for of organic dyes in aqueous and ethanol solutions and in polymer film.

The reduction of strong interfering absorption of atmospheric water vapor and carbon dioxide in infrared and microwave regions is important in various applications. We present an accurate theoretical model and simulation results for nonequilibrium infrared high-resolution absorption spectra of the atmospheric air aiming to study its laser bleaching. Line- by-line spectra are computed using: HITRAN database, modern continuum absorption models, season-latitude atmospheric data. Time-dependent populations of vibrational levels are simulated using kinetic equations accounting for state-by-state processes of vibrational relaxation and laser pumping. The calculations are performed for different altitudes in the atmosphere for selected pumping frequencies of CO- and HBr- lasers. The effects of vibrational and vibration-rotational population inversion in CO₂ and H₂O molecules are studied numerically. In particular, marked inversion of CO₂ vibrational levels has been found to occur at moderate pumping intensities resulting in negative absorption in 8 - 12-micrometer transmission window. The complex altitude behavior of absorption coefficient in 10.6 micrometer P(20) CO₂ line is discussed. The possibility of formation of spectral microwindows with negative absorption in 6.27 micrometer H₂O band is demonstrated. The first results regarding water vapor continuum absorption control by IR lasers are presented.

We extended the method of integral equations to weakly rarefied media when the distance between the radiators is not negligibly small in comparison with the light wavelength. This enables us to calculate the local fields and the dielectric permittivity of some regular and chaotic media.

The local field effects are taken into account in Raman spectroscopy of the essentially anisotropic medium for the first time. The application of the results for the interpretation of Raman spectroscopy measurements of the nonlinear organic crystals is discussed.

The developing method increases multiple the sensitivity of the spectroscopy of liquids by use: optoelectronic increase of interaction length in films or luminescence cooperative processes, multifrequency laser spectra that correlate to differences of indicators and their complexes with toxic metals.

New approaches are proposed to inverse the experimental data provided by the Perturbation Facilitated Optical-Optical Double Resonance spectroscopy technique, and applied to the (alpha) ³II_u, 2³II_g, 3³(Sigma) _g⁺ and 3³II_g triplet states of the Li₂ molecule.

The problem of the study of an ordered movement of the biological systems by high-resolution light scattering spectroscopy is discussed. The class of the objects for investigation of their dynamic properties in the water solutions is determined. The early experimental results of the observed peculiarities of the macromolecular motility by the example of DNA are presented.

The aim of these experiments was a direct measurement of changes in absorption of cellular monolayers under diode laser irradiation. First, a sensitive method for multichannel registration of absorption of a cell monolayer in range 500 - 860 nm was developed. Second, absorption spectra of intact HeLa cells and those after irradiation the monolayer with light at 670 and 820 nm were recorded. Third, the comparison of the absorption spectra and action spectra (five dependences of DNA and RNA synthesis rate and adhesive properties of HeLa cell membrane on wavelength) was performed.

We investigated the dynamic properties of two firefly luciferases: Luciola Mingrelica, that contains the only tryptophan residue and Photinus Pyralis, that contains two tryptophan residues by means of fluorescence spectrochronography method. Relaxation time of protein matrix for Luciola mingrelica is estimated to be 2 ns. The dynamic properties of luciferases differ in spite of similar composition. We investigated also the influence of microenvironment on spectral and kinetic properties of luciferin. Fluorescence decay curves and stationary spectra were measured in 7 different solvents and in complex with luciferase. The closest coincidence of decay curves in the solvents with the decay curve in the complex with luciferase was obtained in water. It means that microenvironment of luciferase is not hydrophobic, as it had been determined earlier.

It is well known that fluorescence microspectroscopy is a powerful tool in the study of biological objects. Fluorescence lifetime imaging is one of the modern and promising techniques applied in these studies. The method implies the detection of not only spectral parameters of some molecules and molecular structures but also the fluorescence lifetimes. Thus, one can easily distinguish between two fluorophores with similar spectral properties but having different fluorescence lifetimes. Additional possibilities are offered by the method for stray light rejection and detection of Raman scattering because of the difference in time-correlation of the excitation, fluorescence, and Raman photons. We suggest the application of an original position-sensitive micro-channel plate photomultiplier as a key element of a newly developed fluorescence microspectrometer designated for the study of biological objects (cells, subcellular structures and organells). We present the first results of the experiments with the test objects. The results obtained clearly show that the new system is rather promising in the studies of living cells and tissues.

Stepwise reversible rearrangement of dicarbocyanines upon excitation of instable primary photoisomers is studied using nanosecond pump-probe laser spectroscopy. The structure of secondary photoisomers, the probabilities and activation energies of the second photoisomerization stage are found. The mechanism of recovering stable molecules upon relaxation of secondary photoisomers is determined.

The method of increasing writing efficiency in 3D optical data storage system is proposed. This method is based on the energy transfer from material with high two photon absorption (TPA) to the photochromic molecules in thin polymer film. This method allows us to increase the writing efficiency of informative media more than one order of magnitude.

The analysis of the results of studying photochromic compounds and systems which exhibit reversible photoinduced changes not only in absorption, but another properties as well (irradiation capability, refractive index, light scattering, nonlinear characteristics) is presented. Multi-mode photoelectrochromic systems are discussed too. These photochromic compounds and systems are candidates for modern optical information technologies and molecular photonics.

Photopolymerization and photoinduced diffusion of the molecular oxygen in oxygen bearing C₆₀ films by (lambda) equals 459, 514 nm continuous laser radiation and by 100-fs, (lambda) equals 395, 410 nm pulses were compared by visual observation of photodarkening spots and by recording the Raman spectra, in the range 200 - 1700 cm^-1, of the irradiated regions. It was found out that in the case of femtosecond pulses, the efficiencies of both photoinduced processes are significantly lower than those in the case of continuous radiation.

This issue is devoted to the elaboration of the physical principles of the new method of reconstructive problem, namely, to the elaboration of stochastic correlative tomography. For the demonstration these theory possibilities, we conduct the mathematical modeling and computer experiment with the following output of the algorithm and the parameter of the real physical experiment in tomography.

The model of laser-induced reduction of the dye with high quantum yield of the triplet state in solid polymer matrix was developed. It allows to explain kinetic patterns of light- induced photochemical gratings formation. For the experimental case the value of rate constant of reaction which defines the grating recording rate was founded.

The two-photon induced photo-destruction of indolyl fulgides, which are rather stable under single-photon excitation are investigated. The mechanism of this type destruction is proposed on the basis of semiempirical calculations of potential energy surfaces (PES). It was shown that the photodestruction of indolyl fulgides is connected with the triplet state population.

Intensities and decay rates of delayed luminescence (DL) initiated by a pulse of N₂ laser or CO₂ laser were employed to probe collisional relaxation of complex molecules (benzophenone -- C₁₃H₁₀O, acetophenone -- C₈H₈O, anthraquinone -- C₁₄H₈O₂) diluted with bath gases: Ar, C₂H₄, SF₆, C₅H₁₂, CCl₄. It was shown that time resolution about 10^-8 sec permit one to divide the V-V and V-T processes for such large and complex molecules, the relaxation occurs in two stages. Upper levels relax through V-V transfer, which completes after several collisions. The collisional efficiencies of V-V process had the values typical for supercollision. The average energies transferred per collision, <(Delta) E>, well correlate with predictions of the simple ergodic collision theory of intermolecular energy transfer. The majority of energy transfer collisions involve V-T/R transfer of relatively small energies. The CO₂ laser excitation method to initiate the DL allowed to obtain only V-T CET quantities because of lower time resolution.

Laser desorption of adsorbed NO, CO₂, SO₂ NH₃ and C₆H₆ molecules from a fused quartz substrate have been studied using mass spectrometry. The desorption was induced either by adsorbate absorption of UV excimer laser radiation or by substrate heating due to TEA CO₂ laser irradiation. The UV resonant desorption was found to be characterized by various laser fluence dependences ranging from linear to highly nonlinear (threshold) one. A powerful KrF laser irradiation of quartz substrate caused changes in the UV desorption processes. An influence of SO₂ surface chemistry on its UV laser desorption was also observed.

The four-photon (3 + 1) ionization of H₂ molecule with population of intermediate Rydberg C¹II_u state has been investigated. We analyzed this process using method of radiative collision T-matrix, where total wave function of the system with accounting for electromagnetic field in the final state is expressed via its elements. Formalism utilized allows to include naturally predissociation channel of intermediate complex H₂^** (u') resonance states concerned with transition into repulsive ¹II_g state. Without field (f equals 0) it causes the ultimate shift of distribution function W₀ to the greater u values with respect to Franck-Condon distribution. Interaction with field in final state forms the additional ionization channels and effects essentially on profile of ion distribution H₂⁺ on final vibrational states that has nonmonotonic dependence on external field strength f. At low field strength f less than 10^-5 a.u. it provides the additional field broadening of resonance levels and shift of spectrum pattern toward the less v values comparing with W₀. This dependence becomes more complicated at higher field strength f greater than or equal to 10^-4 a.u. that is connected with multiphoton character of absorption and appearing of new reaction channels. The dependence of ion H₂⁺ vibrational distribution on strength magnitude is calculated.

The photochemical transformations at the surface of single crystal zircon (ZrSiO₄) induced by the action of continuous CO₂ laser radiation (10⁵ - 10⁶ W/cm²) has been investigated. It has been found that the action of infrared laser radiation on the surface of zircon results in a selective sublimation of silicon oxides as well as in a change of electronic state of zirconium atoms included in the silicate matrix. The change of electronic state of zirconium atoms is confirmed by the change of the relation of K- and L-component intensity in X-ray emission spectra recorded by an X-ray microprobe analysis of irradiated samples. This change is connected with the decrease of a shielding of inside electrons and the delocalization of electron density into position of defects. The appearance of nonequilibrium electronic states of zirconium atoms is accompanied with the creation of the defect metallic clusters, in which the part of oxygen atoms is removed by laser sublimation of silicon-oxygen groups.

Laser spectroscopic measurements are an effective method for the on-line investigation of formation processes of harmful substances during laser treatment of tissue in medicine. Specific radicals like CO, CO₂, CN, OH, CN, CH₂, C₂, NH, SH, CS produced during laser application for cutting and evaporation of tissue characterize the kind of laser tissue interaction. The molecule fragments in the ground or excited states have been detected in dependence on the applied medical laser system by spontaneous or laser induced fluorescence. The chemical reaction processes in the laser tissue interaction zone can be changed significantly by the surrounding gas atmosphere. An increasing oxygen content in the surrounding atmosphere reduces the amount of harmful substances in the laser plume. The laser spectroscopic investigation inside the reaction zone reflects clearly the interplay of complete and incomplete oxidation in dependence on different gas atmospheres in the reaction zone. The application of pure oxygen and oxygen enriched gases is limited in laser medicine because of safety regulating. Therefore water was used as an oxygen donor. The water was added into the laser tissue interaction zone using a water aerosol spray. The oxygen was released during the laser treatment with the result of the water dissociation under the high temperature conditions. The production of toxic and carcinogenic substances was reduced significantly by this method. The cutting efficiency in the case of water spray application is unchanged in comparison to the treatment without water spray but the quality can be improved, as histological investigations demonstrate.

The aim of this work is to control shaping of cartilage under laser heating with acoustic and opto-acoustic approaches. Generation of acoustic signal in cartilage is due to water movement through porous cartilage matrix.

The principles of time-resolved laser opto-acoustic investigation of inhomogeneous medium are discussed. The results of experimental monitoring of human tissue in vivo are presented. The depth resolution may be as high as 15 - 20 micrometer and the depth of investigation reaches 3 - 4 mm.

Optical registration technique is developed and frequency spectra are measured for dynamic shape fluctuations (flicker) in erythrocytes. Flicker spectra are studied in the range 0.03 - 500 Hz, using dynamic microphotometering of single cells in two optical modes: phase contrast regime, and reflection-mode laser probing. The registered spectra are similar to those typical of 1/f noise, with an essential difference: their slope in log-log scale varies with frequency, from -(0.8 divided by 1.2) below 10 Hz to -(1.6 divided by 2.4) above 50 Hz. The spectra measured with backward laser light scattering go systematically higher then those measured in the phase contrast regime. The theory of erythrocyte flicker is developed, based on the eigenmodes analysis of the bending oscillations of the cell envelope, and on the optical problem solution for the contribution from these oscillations to the registered signal. The theory describes quantitatively the spectral curves, and relates their parameters to the main mechanical and shape parameters of erythrocytes: bending modulus of cell membrane, viscosity coefficient of hemoglobin solution, and thickness-diameter ratio of a cell. The difference in the spectra obtained by coherent and noncoherent probing of erythrocytes is explained by specificity of optical mechanisms of the registered signal formation. No firm evidence is obtained for the contribution from the active processes in erythrocytes to the flicker.

The technique of diffusing-wave spectroscopy (DWS) consists in deriving properties of random multiple-scattering media from measurements of the temporal autocorrelation function of scattered intensity. Both the characteristics of light- scattering particles (size, absorption and scattering coefficients, etc.) and the macroscopic dynamic structure of the sample may be studied by means of DWS. The technique has a considerable potential for application in medical diagnostics. We report theoretical and experimental results that allow the method of DWS to be extended to random media with hidden, spatially localized flows of scatterers. Our model experiments were performed with a flow of an aqueous suspension of polystyrene beads confined within a rigid sample made of titanium dioxide particles suspended in resin. We show that the method of DWS allows the noninvasive diagnostics of the flow. As a possible application of the method, we discuss the use of DWS for noninvasive in vivo optical monitoring of blood flow in humans and animals.

Correlation spectroscopy methods are widely used to study dynamical, morphological and optical parameters of biological objects. This work makes an attempt to explore these methods (in particular, due to their expressively) for diagnosing whole blood under normal and pathological states (cardiovascular diseases). Not only morphological characteristics of blood elements are known to change under diseases, but also its biochemical composition does. However, the biochemical analysis of blood is rather time and labor consuming. The paper is directed to investigate the correlation between optical characteristics of light scattering by blood and its biochemical parameters. Samples of whole blood were in vitro investigated for ills with different diagnoses and extend of cardio-vascular diseases as well as for essentially healthy donors. Simultaneous with the above characteristics we have monitored volumetric concentration of lipoproteides, erythrocytes and hemoglobin. The analysis of obtained results has show that the width of spectrum is greater for samples from healthy persons then from ills. Comparison of measured data on frequency spectrum, diffuse reflectivity's, biochemical and morphological blood parameters of the studied samples has shown the high correlation between the spectrum halfwidth and concentration of lipoproteides, erythrocyte setting rate. Some poorer correlation with spectrum occurs for concentration of hemoglobin and cholesterol. Thus, these are revealed an opportunity to design on express non-invasive method for determining the possibility of atherosclerotic disease.

In our previous works we presented our results of experimental investigations of plant bioelectrical reactions to low- intensity local irradiation at certain ranges of wavelengths. It was demonstrated that the qualitative and quantitative estimation of the reaction of plants can be performed with the help of bioelectric potential (BEP) gradients generated by plants. We consider BEP as the difference of electric potentials at the surface of a plant resulting from the difference of the functional activity of cells in tissue and organs. In particular we presented typical plant responses to light stimuli, the action spectrum (AS) of light on the conductive system of a plant in the wavelength range 330 - 1300 nm as well as a transmission spectrum of intact green leaf in the same spectral range. The aim of this paper is the investigation of plant responses to light stimuli in wide spectral range (330 - 3390 nm) including far IR, to obtain new data (transitional characteristics on different wavelengths) and to specify our previous ones (AS, transmission spectrum).

One of major aspects of a problem of restoration (reconstruction) of the internal structure of various objects and other information about their properties considers the reception of the information on distribution of some physical characteristic from their experimentally obtained spectrum of integral projective data received by various methods (emissive, transmissive -- by a physical principle; acoustical, optical, laser, radiological -- by the type of used radiation, etc.). The given branch of investigation is known as a reconstructive tomography. The majority of methods for restoration of the images from their integral projections in reconstructive tomography are based on a fundamental generalized projective theorem with use of Fourier transform. The main difficulty in practical processing of the complex Fourier-like transforms (Laplace, Mellin transforms, etc.) despite of their convenience in analytical calculations and algebra becomes the insufficient speed of data processing for reception of the dynamic distribution image of an investigated physical characteristic. In the present work we examined the possibilities of application in various areas of a reconstructive tomography of the real-domain integral transform offered by Ralph Vinton Lyon Hartley in 1942 for study of a spectra of electrosignals, lastly named in his honor by Hartley transform. Some examples of an effective applications and basic properties of Hartley transform are presented in works of Ronald N. Bracewell. From middle of the 1960-the years there were offered various fast algorithms of calculation of discrete Fourier transform (FFT) which characterized by some advantage in speed of data processing in comparison with discrete FT, but however owing to its complexity and asymmetry FFT concedes in speed of processing to fast algorithms based on Hartley transform.

Techniques for simultaneous display of two en-face images of the retina, an optical coherence tomography image and a confocal image in pixel to pixel correspondence are presented. Such images are obtained from the eye using a fiberized low coherence interferometer and a bulk confocal receiver sharing the same galvanometer scanner and interface optics directing light to the eye. The images have different depth resolution and complement each other i the process of system adjustment and measurement.

Results of experiment on dental solid tissues treatment with help the new laser-plasma method used the designed by authors the high energy Nd-glass picosecond laser are informed. Advantages of the method are the dot source of plasma, low transmission of heat deep into treated material, etc. According with results proposing arrangement productivity is higher than setup of German company <<KAVO>> one.