The liquid crystal director-colloidal particle surface interaction in filled liquid crystals causes the thermally-induced director fluctuation correlations to be screened. This is consistent with the experimentally observed reduction in the thermal director fluctuation-induced Rayleigh light scattering in filled liquid crystals. The colloid-mesogen interaction also induces director non-uniformity in filled liquid crystals, thus further modifying the spatial dependence of the director fluctuation correlations, and shifts the critical temperature at which the isotropic phase loses its stability with respect to nematic fluctuations. The shift is specifically particle-size dependent, and this will enable the phenomenon to be recognized experimentally.

Long-range forces between ultra-fine particles imbedded in liquid crystal (LC) matrices result in intriguing colloids. Embedded inorganic particles in LC contribute to the properties of the LC matrix. For example, doping of a LC with ferromagnetic particles resulted in a strong enhancement of magnetic properties of the LC. Large (>>µm) colloidal particles form defects in LC matrices due to strong director deformations and ensembles of these particles and defects can form complex structures. Small (<<µm) particles at its high concentration (>2-3% by weight) create almost a rigid LC suspension. Here we show that at low concentrations LC nanocolloids appear similar to a pure LC with no readily apparent evidence of dissolved particles, but possess unique properties. The diluted suspensions are stable, because the small concentration of nanoparticles does not significantly perturb the director field in the LC, and interaction between the particles is weak. At the same time, the nanoparticles share their intrinsic properties with the LC matrix due to the anchoring with the LC. In particular, doping a nematic LC matrix with ferroelectric nanoparticles results in a suspension, which possesses an enhanced dielectric anisotropy and reveals ferroelectric and paraelectric properties inherent to the nanoparticles.

New chiral compounds 3R-methylcyclohexanone derivatives were synthesized. These compounds were revealed to exhibit the mesomorphic behavior within rather wide temperature ranges. Types of formed mesophases and phase transition temperatures were determined by polarizing microscopy, differential scanning calorimetry and small angle scattering of X-ray. Mesomorphic properties of the new chiral compounds were compared with those for the chiral 2-arylidene derivatives of 3R,6R-3-methyl-6-isopropylcyclohexanone (d-isomenthone) studied earlier. Distinctions between these two types of compounds in an ability to form mesophases and also in twisting properties as chiral dopants in induced cholesteric mesophases are considered.

The paper is devoted to the research on the ionic liquid crystals in the metal alkanoate systems. They present a new class of ordered ionic solvents which combine the properties of usual ionic liquids with ones of liquid crystalline solvents and may be promising materials for the application as universal matrices for modern fields of techniques such as optoelectronics and laser techniques. The main regularities of ionic liquid crystal formation and stability have been established.

The use of two-photon absorption (TPA) as mechanism of optical limiting puts a question about material, whose structure would provide effective TPA in initially transparent medium. The advantages of use of impurity mesomorphic systems in the tasks of optical limiting are discussed. It is necessary to take into account various detrimental effects on process of limiting may arise in molecular systems in conditions of high-power photoexcitation and high concentrations of excited fragments.

We consider the effect of magnetically controlled anchoring of ferro-nematic suspensions. Together with co-authors we recently found that application of weak magnetic field to a cell filled with the ferro-suspension induced an axis of easy orientation of the director of liquid crystal on a polymer surface (Mol. Cryst. Liq. Cryst., 375, 81, (2002). Here we present a simple theoretical model of the effect that assumed coupling between liquid crystal and the applied magnetic field. This coupling is assumed to be a combination of the interaction between magnetic field with ferro-particles magnetic momentum on the one hand and LC director anchoring with these particles on the other hand.

The electro-optic properties of nematic liquid crystal (LC) E7 filled with non-organic monodispersed nanoparticles (MNP) are investigated. As filler we used spherical MNP of antimony pentoxide (Sb₂O₅) and silica (SiO₂) having similar size. We investigated both non-stabilized and polymer (P) stabilized LC-MNP suspensions. By variation of the component concentrations different system morphologies were obtained. It is show that insertion of MNP in LC leads to drastic increase of light scattering which can be effectively controlled by the electric field. We obtained moderate driving voltage, short response time and relatively high contrast in the samples with optimized concentration of MNP. The improved contrast and response time were also achieved in LC-P composites by doping them with MNP. In both polymer stabilized and non-stabilized composites the contrast was higher in case of Sb₂O₅ filler. It is show that particle material and geometrical size strongly influence electro-optic properties of composites. The concentration dependencies of LC-MNP-P composites can be explained assuming strong absorption of MNP by polymer during photo-induced phase separation.

We report on the first observation of surface-mediated reorientation effect in LC with fullerene-containing aligning polymer. We found a strong light-induced change of the Friedericksz transition voltage in a dc-field. The Friedericksz transition was measured in a LC cell containing reference and command surfaces. The reference surface, covered with the photoaligning material fluoro-polyvinyl-cinnamate (PVCN-F), was irradiated with polarized UV-light providing strong unidirectional planar alignment. The command surface was covered with a mixture of PVCN-F and fullerene in a 2:1 ratio. This layer was also irradiated with UV-light to obtain unidirectional planar alignment. The 90°-twist cell (thickness ≈ 30 μm) was filled with LC 5CB in the nematic phase. We found a strong increase of the Friedericksz transition voltage as the intensity of the incident beam from He-Ne laser was increased. The effect was reversible and depended on the sign of electric field applied to the cell. We suggest that the increase of Friedericksz transition voltage arises from charge injection into the LC bulk from the fullerene-containing alignment layer. An enrichment of the ion concentration near the surface causes a redistribution of the electric field in the cell, localizing it more strongly near the surface, and, thus, leading to an increase of the voltage necessary to reorient the director.

The effect of a hidden photoalignment of nematic liquid crystal (LC) after the irradiation of the cell with linearly polarized light in the isotropic phase was recently observed (Phys.Rev.E, 021701, 63, (2001). It was found that the effect was caused by light-induced desorption and adsorption of dopant dye molecules on the aligning surface. The desorption of the dye molecules resulted in the anisotropy axis perpendicular to the light polarization whereas the light-induced adsorption causes the anisotropy parallel to the light polarization vector. Competition between these processes determined the resulting direction of the easy axis in a nematic phase. In the present paper we distinguished these two mechanisms by using different geometries of the irradiation of the cell.

Photochemical E-Z isomerization reaction in the series of chiral 1R,4R-2-arylidene-p-menthanone derivatives has been studied and the behavior of starting materials and photoproducts in liquid crystalline systems was characterized. The differences in photochemical properties of the studied compounds with several benzene rings in arylidene fragments and those containing ester linking groups were revealed and discussed.

The possibility of using a new method of the wave equation solution for computer modeling of diffraction on a liquid crystal amplitude phase mask, which consists of squared cell, for a wavefront reconstruction, structured light beam generation and image composition was considered. The method is based on a new integral approach to modeling the plane wave diffraction on an arbitrary two dimensional aperture by investigation of the singular wave component as informative part of diffraction field. It was shown that the result of diffraction on arbitrary aperture being treated as a discrete sum of elementary unit cell waves and diffracted field can be presented via orthogonal wave functions that play a role of eigenmodes as plane waves in free space. Developed on the basis of proposed integral representation the effective algorithm is useful for providing analytical studying and numerical modeling the aperture diffracted field and allows eliciting features of spatial behavior. The specific form of the convolution kernel that describes the diffraction with taking into account the size of cell allows alternative reconstruction procedure of a diffraction pattern. Application of new procedure to practical diffraction related phenomena may improve the processing efficiency without creating any artifacts associated with the diffraction field. The extension of new method of modeling diffraction on liquid crystal panel and possibilities of its practical application to information display are considered. The result of theoretical study and computer modeling the diffraction on a discrete matrix of square elements in near field with Unit Cell Wave concept applied to arbitrary surface description was represented. Conclusions regarding the possibilities to represent the arbitrary fields by using the discrete matrix of squared cells are arrived at. The technique for optical coding an adaptive optical hidden image in holographic elements has been proposed. A structure of a system that seems promising to produce a like hologram and method of operation directly images a pattern, which is previously calculated using a computer and displayed on the liquid crystal panel was explained. It was discussed the method of complex amplitude phase field distribution modeling in screen plane for three-DI scene synthesis as well as capabilities and characteristics of amplitude phase liquid crystal display for dynamic image visualization by using the "wavegram". This technique and algorithm for an aperture - synthesized image of three-dimensional objects can be applied to holographic screen technology development, which may have ever-growing use in many applied areas of systems for three-dimensional information visualization.

Two-wave mixing holography experiments with Raman-Nath diffraction in ionic lyotropic liquid crystals (ILLC) pure and doped by polymethine dyes is observed for the first time. The laser generation in ILLC films doped by polymethine dyes is demonstrated. Pure and doped ILLC is considered as new perspective photorefractive material for applications in signal and information processing.

Electric and optical properties of ionic lyotropic liquid crystals (ILLC) with different ionic polymethine dyes (cation- and anion-types) as well as neutral fluorescein (DILLC) are studied. Dielectric characteristics of the ILLC and DILLC are investigated before and after applied stationary electric field. The comparison analysis of the electric and electro-optical properties of different DILLC has been carried out. Stationary electric field, which exceeded a certain voltage (~6V), causes DILLC irreversible electrochemical changes and bleaching films. It has been established that the influence of electrodes, DILLC boundary layers and near electrode electrochemical processes give the main contributions to the electro-optical effects in DILLC.

Selective reflection spectra have been studied for cholesteric matrices doped with certain steroids of vitamin D group, and substantial effect of the dopants upon the helical pitch was noted. Under UV irradiation, shifts of selective reflection peaks were observed. It is argued that the effect studied can be used for monitoring of vitamin D formation reactions induced by UV irradiation, thus being a base of bioequivalent UV dosimetry.

The nematic liquid crystals (LCs) can be converted into cholesteric LCs by different chiral dopants. For the first time the dynamics of a cholesteric phase induction was investigated on dissolution of the single steroid crystal (vitamin D isomers and relative compounds) at the nematic droplet and the new effect of the crystal rotation has been discovered. In all cases the correlation between the rotation direction and screw sense of the cholesteric helix was found. A theoretical model and interpretation of the rotation effect has been proposed.

Twist-cell with infinitely rigid director anchoring on the one planeparallel surface and periodic finite director anchoring on another surface is considered. The conditions for anchoring parameters that allow obtaining the director structure similar to that in the twist-cell with homogeneous anchoring are determined. In this case the expression for effective director anchoring strength is obtained. The effect of “supporting” of director anchoring in the area where the real anchoring strength equals zero is found.

We consider director configurations of cholesteric liquid crystal (CLC) cells with two plane confining substrates. Exact solutions of the Euler-Lagrange equations for out-of-plane orientations of the easy axes that correspond to inhomogeneous conical structures of CLC director are derived. We study dependence of the CLC twist wavenumber on the free twisting number assuming that anchoring energies at the substrates are either equal or different. In both cases this dependence is found to be generally discontinuous with hysteresis loops an bistability effects involved. For CLC cells with identical substrates and planar anchoring conditions the jump-like behavior only disappears in the weak anchoring limit. Contrastingly, when the anchoring strengths are different, there is the finite value of anchoring below which the dependence becomes continuous. Another effect is the appearance of the gap between the adjacent twist wavenumber intervals representing locally stable director configurations. We calculate the critical value of anchoring asymmetry and present the results of numerical calculations.

We found a thermally-induced threshold reorientation of the nematic liquid crystal from homeotropical alignment to planar one. The fenomenon was observed in a symmetric cell with inner surfaces covered with fluoro polyvinyl-cinnamate. This threshold reorientation is an anchoring transition of the second order. We suggest that a competition of aligning abilities of flexible polymer fragments and main polymer chains is the basic reason for this phenomenon.

A new method of light propagation control in planar waveguides filled by nematic liquid crystals is reported. Permanent deviation has been achieved by light induced reorientation of a selected area of dye-doped liquid crystal cells. Reversible deviation has been achieved by inducing Bragg reflection on the excited mode of the waveguide. The Bragg diffraction grating is produced by the liquid crystal itself, using short-pitch interleaved electrodes.

Photorefractive properties and possibility of guest-host effect application for real-time holography have been described. As the hosts isothiocyanate nematic liquid mixtures with positive dielectric anisotropy and as the guest antraquinone dyes were used. Enhancement of ultraphotorefractivity properties of these LC systems has been discussed. In dye-doped nematic liquid crystals high diffraction efficiency approaching 20% were obtained. Fast optical grating formation with a time constant τ of few ms have been observed. The results of our main investigations concentrated on the behavior of thin (5 ÷ 20 µm) cells with pure isothiocyanate nematic liquid crystal with high optical anisotropy (▵n > 0.35) and antraquinone doped have been presented. The dependence of grating formation on strength of applied dc and low frequency of ac electric field, configuration of light polarization and nematic director orientation were reported.

This work concerns the experimental study of potential possibility to use the ITO/5CB/Si/Al structures based on a low resistive silicon as liquid crystal spatial light modulator (LC SLM). It is shown, that in such type of structures there are at least two charge processes causes the opposite influence on electrooptic reaction of structure. First process is connected with ion charge accumulation at silicon surface that induces the formation of depleted surface layer in silicon by means of a field effect. Second one is due to leakage current through Si/liquid crystal interface that decreases a photosensitivity of structure. Because of sufficient large ion currents achieved in such a type of structure as well as charge accumulation the possibility exists to form the local variable area of high ion concentration in liquid crystal layer that can play a role of a “quasi”-electrode which enables to modulate a surface conductivity of silicon. Ion control of photosensitivity as well as dynamic selection of input image by the structure has been demonstrated.

For material processing and laser machining, it is important to shape intensity and phase profiles of the laser beams. For dynamic beam shaping, we suggest the method based on energy exchange during self-diffraction of laser beams in the photorefractive materials. For applications, related to use of the powerful lasers we have tested a possibility of beam shaping by holographic optical elements, recorded in Photo-Thermo-Refractive (PTR) glasses, developed in CREOL. The gratings in PTR glasses are stable up to 400°C with laser-induced breakdown energy threshold of 10 J/cm² in 1 ns pulses at 1064 nm. High diffraction efficiency more than 95% of gratings recorded in PTR glass allows to achieving high energy transfer that is vital for commercial laser applications. Preliminary results show that flattop distribution of laser intensity may be realized in the diffraction orders.

We report the experimental investigation both, of the one - dimensional and two - dimensional bright screening spatial solitons in a promising photorefractive crystal of barium - calcium titanate doped with iron. The effects of the partial trapping of the spatially incoherent ordinarily polarized background light within the soliton - induced planar waveguide as well as the regular oscilations of the light beam intensity and width during the beam self - focusing are observed. For the crystal sample, doped with higher dose of iron (290 ppm), we also find the self - defocusing of light beams due to the light - induced negative photovoltaic lens in the absence of the externally applied electric field.

The paper presents the results of the complex investigation of linear and nonlinear parameters of new organic compound type - polymethine dye base (PDB) - 1-pentafluorophenyl-4-phenyl-5,6,7,8-tetrahydro-8-[(4-dimethylaminophenyl)methylene]-quinoline. For the first time thin films on glass substrate from this material were deposited by physical evaporation in vacuum. Linear absorption spectra of base films and base solutions were investigated in the wavelength range 300 - 1100 nm. Nonlinear properties of three films with thickness of 247, 350, 535 nm were studied with Z-scan and spatial profile analysis techniques in picosecond range of pumping pulses duration at the fundamental wavelength of YAG:Nd³⁺ laser 1064 nm. We observed darkening/bleaching effects of different magnitude (2 - 20%) of total transmittance in dependence on films thickness. It was estimated effective third order nonlinear susceptibility χ⁽³⁾ ≈ 10^-5 esu. Such high nonlinear response can be explained by presumable cascade process of PDB molecule excitation which is simultaneously in resonance with pump wavelength 1064 nm (1.17 eV) and its harmonics 355 nm (3.48 eV).

In the paper we theoretically consider the dynamics of the inner field generated by recharging trap waves propagation and spatial-temporal features of the photoinduced light scattering caused by these phenomena in photo-ferroelectrics with two donor levels under steady illumination by laser beam. The transverse instability of the interacting light beams and both the photovoltaic current from each donor level and the diffusion mechanisms of carrier transfer are taken into account in the proposed model. It has been shown that, under the definite relation between the photoionization velocities and anti-collinear Glass vectors of the donor levels, among all possible scenarios of transverse instabilities the boundary circle will be realized in the perfect crystal. Due to this phenomenon the periodical photoinduced light scattering appears. So the great attention has been paid to the description of the optical autowaves generation in ilmenites. All the main theoretical results are in a good agreement with the available experimental data.

We studied third-harmonic generation (THG) in reflection geometry from porous silicon layers grown on (110) silicon substrates. A significant (more than 10 times) enhancement of the THG efficiency compared to crystalline silicon was found for the samples prepared on highly doped substrate, whereas for the samples grown on low-doped substrate the THG was much less effective than for crystalline silicon. This fact is connected with fluctuations of the electric field of the pump laser irradiation in the layers of anisotropically distributed silicon nanocrystals having different shape and sizes.

The photoluminescence spectra of compositions are investigated on the basis of thermoplastic polymers and semiconductor filler of CaGa₂S₄:Eu at the range of wavelength λ=350÷700 nm. Is shown, that the photoluminwscence spectra depend on the volume contents of filler, polarity of polymer and from the condition of electrothermopolarization. It is supposed, that the observable changes of spectrum are connected to energy of activation, process of overlapping of polymer with filler and change supermolecular structure of polymers and excitation in the CaGa₂S₄:Eu the new luminescent centers.

Instead of unstable solutions for conventional four-wave mixing equation set, we obtain the stationary soliton solution for the dynamic grating amplitude and stable auto-oscillations of the dynamic grating. The dynamics of grating recording is described by the sine-Gordon equations in transmission four-wave mixing with non-local grating. The method to calculate the grating amplitude profile and the both steady state and oscillation regimes is developed.

We study the processes of formation of dark photovoltaic spatial soliton in photorefractive LiNbO₃:Ti:Fe waveguide. The 2-D distribution of the optical field is taken into account to define the nonlinear change of the refractive index.

We report an experimental observation of propagation of light in waveguide formed on Y-cut LiNbO₃ crystal by helium implantation and combined proton and copper exchange. The buffer layer formed in result of ion implantation enjoys depolarization properties and provides intermode energy exchange. The parameters of this buffer layer is defined from mode spectroscopy. Mode diffraction on the 2-D grating-like periodical structure formed by defects of layer is observed. Appearance of such defects we explain by features of copper-doped helium-implanted optical LiNbO₃ waveguide fabrication process.

In this work we created analytical model of dynamics of nonlinear process of recording and reading the hologram in photopolymer media taking into account photoinduced absorption of photopolymer. The analytical model is based on the equations Lorentz-Lorenz and relations of the theory photopolymerization. Photoinduced absorption has been described with the help of the logarithmic function on the base of experimental data. Then experiments investigation was conducted. The record of the holograms was conducted under convergence angle 30⁰ between laser beams. The data of experiment and the analytical model have allowed determining basic physical parameters of photopolymers. The researched photopolymer was made in Institute of Organic Chemistry of the Siberian Separation of a Russian Academy of Sciences (Novosibirsk).

The photocatalytic activity of different porous layers of anatase nanocomposites has been monitored by measuring changes of the optical response of Rhodamine 6G water solution under UV irradiation in the presence of anatase films. We have produced series of porous anatase films with different methods to investigate their photocatalytic activity and its dependence on the parameters of the layers. Integrated sphere transmission and reflection spectra (200 - 1000 nm) with 3D angular resolved light scattering data gave a possibility to estimate the correct intrinsic absorption coefficient, the dispersion of the refractive index, the porosity (32 - 39%) and the thickness (90 - 1340 nm) of the samples. We have estimated the energy of the optical band-gap for both direct (3.66 - 4 eV) and indirect (3.33 - 3.4 eV) transitions. It has been shown that the photocatalytic activity depends sensitively on the nanopores which is determined by the molecular weights of pore agents.

As a rule, an initial field of the optical vortex at the fiber input transforms into a mode mixture through a short distances due to slight external perturbations so that the field at the fiber output is not suitable for different optical vortex applications in fiber-optical sensors etc. However, as it is shown in the given paper, the tunneling effect that acts between two near by low-mode fibers enables us to select the vortex and other modes into different waveguide canals. The theoretical and experimental results illustrate such the amazing process.

Studies were carried out of the low-temperature optical and photoelectric properties of Ti-doped CdTe and Cd_1-xHg_xTe crystals. The absorption is due to intracentral transitions from the main ³A₂(³F)-state to excited ³T₁(³P)- (1.15 eV) and ³T₁(³F)-(0.65 eV) states. It was shown that the maximum of photogalvanic current band corresponds to the energy 1.12 eV. It indicates that the excited ³T₁(³P)-state of the Ti²⁺ ions is in the resonance with the conduction band and is located near the bottom at a distance not more than 50 meV. The analogous structure of the absorption and photogalvanic current spectra appear also the Cd_1-xHg_xTe:Ti crystals. In this case the long-wave edge of absorption band is some what prolonged. Therefore the use of Cd_1-xHg_xTe:Ti crystals makes it possible to move the spectral region of their photosensitivity to the long-wave side. On the base of the results of photoluminescence and photogalvanic current spectra it was shown that main structural defects for the investigated crystals are V _Cd, and also acceptor complexes of type (V^2-_Cd + D⁺)^-. These defects participate in compensation of charge in the investigated crystals, which are semiinsulating and therefore suitable for carrying out the photorefractive measurements.

The experimental research of dynamics of the pulse vortices in the low mode optical fibers with the step index of refraction is considered. For the coaxial excitation of the fiber the pulse power maximum is transmitted by the carrier fiber mode, for the non axial excitation the majority of fiber modes is observed with the equal power. In this case as a result of mode interference there are the areas with the vortex structure of the field, which do not disappear even in absence of the input vortex pulse in contrast to the coaxial excitation.

The method of the micro-domains formation in photorefractive crystals near the illuminated area polarized due to the screening effects is developed. The micro-domain shape and physical properties are studied in the phenomenological Ginsburg-Landau-Devonshire theory framework with respect to the semiconductor properties of ferroelectric medium. The spontaneous electric induction distribution in the micro-domain is shown to depend on the surface charge distribution on the boundary between illuminated area and the other system. Owing to the surface density peculiarities the transversal micro-domain size is revealed to be much smaller than longitudinal one.

This paper is devoted to the investigation and computer modeling of radiation and thermal decomposition of luminescent polystyrene compositions. It has been shown, that the stability of the optical properties of luminescent polymer composition depends on its material structure. On the basis of quantum-chemical calculation has been obtained the possible products of PS gamma-radiolysis and the effect of formation of fragments with conjugated double bonds and products with quinone structure has been investigated.

A series of aliphatic polyureas with chromophore moieties in the polymer chain, such as 7-amino-2(4’-aminophenyl)benzoxazole, have been prepared. The absorption and fluorescence spectra of these polymers as well as corresponding chromophore-containing model urea (product of condensation of 7-amino-2(4’-amino-2’-hydroxyphenyl)benzoxazole and phenylisocyanate) were studied and compared. It was found that the special feature of the model compound and polyureas is the large value of Stokes shift due to the presence of a hydroxy group in the ortho-position to the nitrogen atom of the benzoxazole ring. The model of the excited-state proton transfer in molecules containing fragments of 2-(2’-hydroxyphenyl)benzoxazole has been used for the description of bathochromic shift in emission spectra of polymer solutions and films. According to this model, the proton remains predominantly on the phenol oxygen while in the ground state (enol form). Upon UV excitation, in the first excited singlet state, the phenol is a considerably stronger acid and the nitrogen is a stronger base. Thus, the proton is transferred from the oxygen site to the nitrogen site, and the isomer formed (S’₁*) is more stable than the isomer before proton transfer (S₁*) S’₁* can be then regarded as a vibrationally excited form of S₁*. Then the molecule de-excites to the ground state, emitting a photon. In the ground state the enol form is again the more stable form and the proton will then transfer back to the oxygen. S’_o is also a vibrationally excited state of S_o. Because of this process the absorption and fluorescence spectra of model urea and polyureas do not intersect and the value of Stokes shift is about 6000 cm^-1.

This paper reports quantum-chemical characterization and structural optimization of α-cyanonitrostilbene, nitrostilbene derivatives and DR, DMNPAPE, C3 chromophore toward a multifunctional amorphous material with magnitude photorefractive performance. The calculations were carried out in an PM3 approximations (HyperChem 7.0). It was founded the relationships between electronic structure and nonlinear optical activity of chromophores and presents the perspectivity of applying the quantum chemical methods for prediction of photorefractive properties of polymers materials.

Until the present time it is commonly supposed that optical vortices (screw or edge wavefront dislocations) are generated either by natural or artificial phase nonuniformity (phase masks, compute-generated holograms, optical edges and so on) located on a light beam way (or inside a laser cavity). A nonuniformly polarized beam is regarded as a field with a fine wave structure, bearing vector singularities such as disclinations, C-lines and L-surfaces without connection with optical vortices. Nevertheless, as it will be shown later on the fine polarization field structure can be transformed under certain conditions into typical phase singularities - optical vortices and vice versa. Moreover, the energy efficiencies of these transformations are considerably higher and constructions of corresponding devices are more simpler than those connected with the usual vortex generation. The aim of the given paper is experimentally and theoretically to study a singular field structure of a light beam after the single-axis crystal in order to reveal the physical mechanism of polarization and phase transformations.

Laser beam after passing through crystal or fiber-optical elements gains a sharply inhomogeneous field distribution in its cross-section. The polarization structure of the radiation contains a number of singular points that form a skeleton of the given field. In the paper the main principles of construction and functioning of the computer differential polarimeter for analysis of these singular points are considered both experimental and theoretical aspects.

Wave caustics formed after short pieces of a multimode fiber have a vortical nature. Such assertion expressed by M. Berry as early as 1980, is the subject of consideration of the given experimental work. The caustic near its cuspidal point contains the vortices in the coupled states with the twofold topological charge. Transition of the wave caustic is accompanied by the vortex sign conversion. At the cuspidal spike the two vortices are unified in the vortical unfolding.

We investigate the mode structure of a weakly guiding anisotropic optical fiber, in which the anisotropy axis rotates in a transverse plane with z increasing. It is demonstrated that at certain values of the anisotropy pitch the spin-orbit coupling is in effect damped and 1=1 modes of the fibers are almost pure linear optical vortices. Polarization corrections to the propagation constant are found. It is demonstrated that in some limiting cases the rise of such corrections can be explained as a manifestation of topological Pancharatnam-Berry’s phase.

It is represented the theoretical results confirming the existence of the optical vortices after a low mode fiber end, while there are no free optical vortices propagating along the fiber itself.

The high-intensity singular beam turns out to be created by means of the ordinary cover glass for a microscope. For this it is necessary to place the edge of the cover glass into the high-power fundamental laser beam. At the expense of the technical wedging of the cover glass beyond the transparent appears the high-quality singular beam bearing the optical vortex. The given paper represents the physical mechanism of such process illustrated with the vast experimental and theoretical results.

The combined singular beams generated by saddle-like imperfections of the cover glass surface in IR spectral range is subjected to the unfolding process near the focal plane of a microobjective. As far as such beams have their intensity profile similar to those of the optical vortices with the quaternary topological charge they can be exploited for the trapping and transportation of large micro particles. In contrast to the ordinary high-order optical vortices being unstable against the slight perturbations of the beam's shape, the given singular beams conserve their topological structure to trap and carry over the particles up to 200 μm in sizes. This fact is discussed in detail in the given work.

No Abstract Available

Interaction of DNA and phospholipids from Carcinoma Guerina resistant and sensitive cells of Wistar line rats with anti-cancer drugs - cis-platin and doxorubicin (DOX) have been studied in vivo and in vitro experiments. Surface enhanced infrared absorption (SEIRA) spectroscopy was applied for registration of conformational changes in DNA and lipids induced by anti-cancer drugs. It has been shown in vivo experiment that doxorubicin influences less structural disordering of the membrane than cis-platin. Cis-platin creates irreversible complex with memebrane phospholipids, strongly interacting with phosophates and carbohydrate chains. Doxorubicin influences the ordering of carbohydrate chains and does not strongly influence phosphate heads. This change seems to be partially reversible. In contrast, in vivo experiment the doxorubicin strongly influences the DNA structure, leading to DNA stabilization and formation of new H-bonds in DNA-doxorubicin complex. We have not registered the interaction of DNA with cis-platin in vivo experiment. Experiment in vitro for cis-platin incubation with phospholipids from cancer cells during 0.5 hour at 37°C has not shown those drastic structural peculiarities that it was observed in vivo experiments.