This PDF file contains the front matter associated with SPIE Proceedings Volume 11024 including the Title Page, Copyright information, Table of Contents, Introduction (if present), and Conference Committee listing.

The formation of iron silicide nanocrystals (NCs) and their embedding into monocrystalline silicon was studied. Solid phase epitaxy of 0.4 nm Fe at 630 °C resulted in formation of NCs consisted of β-FeSi₂ and ε-FeSi phases. Annealing of NCs at 750 °C for 90 min led to transformation of β-FeSi₂ and ε-FeSi into α-FeSi₂. On the other hand, silicon layer growth over as-formed NCs, at the same temperature, resulted in formation of single phase NCs consisted of β-FeSi₂. Silicon deposition rate proved to be the crucial point for a full embedding of NCs. The rate of 1 nm/min resulted in emersion of NCs to the surface during silicon overgrowth irrespective of Si cap layer thickness, while the rate of 8 nm/min led to the full embedding of β-FeSi₂ NCs. Both incompletely and fully embedded β-FeSi₂ NCs have epitaxial relationship and stress favorable for an indirect to direct band-gap transition at Y point.

Semiconducting thin films of titanium oxide (TiO₂) transparent in the UV-visible region were prepared on mica surface by the liquid-phase deposition method. Their irradiation by laser at 405 nm induced photoluminescence at 1700 nm. It was shown that film refractive index (n) depended on the wavelength.

The mechanisms of formation of the spectra of interband optical absorption in nanosystems containing aluminum oxide quantum dots, placed in the matrix of vacuum oil, are presented. It is shown that the electron transitions in the band of the electron-hole pair states cause absorption in the ultraviolet wavelengths, and cause the experimentally observed significant blurring of the absorption band.

This work deals with the field of dielectric photonics in a terms of development of dielectric microstructures which allows obtaining compact devices for controlling optical radiation at wavelength scales, providing opportunities for enhancing the luminescence intensity of sensitive layer in optical chemical sensors. One of the directions of the dielectric photonics is freely propagating optical radiation transformation by the axisymmetric microstructures into a high-intensity light beam of up to several wavelength extent and a lateral dimension of up to several tenths of the wavelengths, called as the "photonic nanojet." Here we present the simple, low-cost technique for dielectric microstructures developing and demonstrate the direct observation of luminescence enhancement via photonic nanojets formed by obtaining microstructures.

The theoretical analysis of the light induced mass transport task was executed in the nanosuspension in a homogeneous light field. As a result of the analytical solution of the light induced mass transport task it was obtained an expression for the deflection angle of the beam in a pseudo-prism. The using of high intensities of the reference beam allows significantly increase the efficiency of the beam deflection method. The results are relevant in the study of the dispersed liquid media, as well as optical diagnostics of such materials.

In the first Born approximation, differential cross sections of bremsstrahlung passing through an external homogeneous electric field were obtained and numerically analyzed [1]. Two cases of electron motion in an external field are considered: 1.) the electrons emitted by the source fall on the potential barrier of the external field, passing through the lattice of Coulomb centers. 2.) the emitted electrons are accelerated by an external electric field. And after passing through the layers, the Coulomb centers are absorbed by an absolutely black wall (located at a macroscopic distance from the scattering centers). Different configurations of elementary cells are considered. It is shown that when the geometry of the cells is changed, the structure of the bremsstrahlung, due both to the superposition of the motion of the emitted particles in the field of the lattice centers and the external field, and to the interference reflected from the potential barrier of the radiating particles, varies noticeably.

Radiation resistance and optical characteristics were researched for β- and γ-radiated LiNbO₃:ZnО crystals doped in the wide range of concentrations ([ZnO] ~ 0.04 – 5.9 mol% ZnO in a crystal). We have detected optical transition of β- and γ-radiated LiNbO₃:ZnО crystals in dependence on the dopant concentration and type and dose of radiation. We have revealed connection between optical and radiation resistance and their dependence on dopant threshold effects.

Due to the Raman spectra structure changes were searched in a LiNbO₃:Zn (0.04÷5.84 mol %), LiNbO₃:Mg(5.1 mol %) and LiNbO₃:В (0.08÷0.18 mol %) single crystals series with the varying of the dopant concentration. Optical homogeneity and photorefractive properties were researched by photoinduced light scattering. Analysis of IR absorption spectra of LiNbO₃:Zn (0.04–4.46 mol % ZnO) and LiNbO₃:Mg (0.19–5.91 mol % MgO) single crystals in the stretching region of OH– groups has been used to gain insight into composition-dependent structural changes in the crystals. The results demonstrate that, characteristically,the OH– groups occupy different sites in the doped and congruent LiNbO₃ crystals and have different quasielastic O–H bond constants in their structure. In stoichiometric lithium niobate crystals, all of the OH– sites and quasi-elastic O–H bond constants are identical. At threshold Zn and Mg dopant concentrations, the frequencies, widths, and intensities of the observed lines change sharply. The linewidths in the spectra of the LiNbO₃:Zn crystals near their first concentration threshold (≈2.0 mol % ZnO) and the LiNbO₃:Mg crystals near their first and second concentration thresholds (≈3.0 and 5.5 mol % MgO) decrease markedly, indicating ordering of the position of the OH– groups in the structure of the crystals.

In present paper issues of obtaining strontium bismuthate samples, which cation sublattice has more then 50% of strontium atoms, for the research of photocatalytic properties are investigated. Solid phase synthesis method is suggested as a method of obtaining samples. Critical concentration 75% of strontium atoms in cation sublattice is discovered. If concentration exceeds 75%, formation of strontium bismuthate crystalline lattice is not observed. Shown that usage 35- 40% of strontium carbonate as a co-catalyst lets significantly increase photocatalytic activity of strontium bismuthate.

The work has investigated influence of heating in vacuum on phased composition and magnetic properties of SPS ceramics based on hematite and sintered at various temperatures. Vacuum heating of SPS ceramics higher than 650 K has been established to promote partial hematite reduction to magnetite and metallic iron. Temperature interval of reduction and amount of hematite participating in reduction have been shown to depend on sintering temperature of the ceramics.

Here, we report a green synthesis of ZnS and Mn²⁺ and Cu²⁺-doped ZnS quantum dots (QDs) stabilized with polyampholyte chitosan derivatives – N-(2-carboxyethyl)chitosans (CEC) varying in the degree of substitution (DS). It has been shown that the fabricated ZnS nanoparticles have spherical shapes and low polydispersity. The average size determined by means of transmission electron microscopy was 2.2±0.2nm and 3.6±0.6nm for CEC with DS 0.7 and 1.0, respectively. ZnS QDs showed only one sharp emission peak in the UV range (~370 nm) related to the sulfur vacancies. Photoluminecent spectra of ZnS doped with Mn²⁺ and Cu²⁺ showed emission peaks at 599 nm and 383-395 nm, respectively. A significant increase of the luminescence intensity was observed for Zn:CuS QDs incubated at 80°C. The metal:S ratio is slightly higher than the stoichiometric-favored one for formation of brighter Zn:MnS QDs.

It was described the light induced currents in thin metal-ferroelectric-metal sandwich system. The effect was observed in doped lithium niobate crystals with two electrodes of different metals. The light induced response includes the photovoltaic effect and the thermoinduced effect. It was proposed the model of the investigated phenomena resulting from field contact potential difference on the borders of section of metal-ferroelectric material.

Different LED light treatments (monochromatic royal blue - RB, blue - B, green G, yellow - Y, red - R, deep red - DR, and polychromatic cold white - CW, white - W, warm white - WW, full spectrum - FS, and the newly constructed Sun box - SB) on potato plantlets in vitro were studied. Longwave monochromatic light sources cannot be used for micropropagation of virus-free material due to producing the fragile stems and poorly developed leaves. Two LED lights (WW and FS), were excellent sources for micropropagation. . Investigation of different light brightness in SB revealed the optimum at 135 μmol/с*m² , which activated plantlet growth, and induced green and root mass accumulation. Such illumination parameters can be usefull for shortening the time of vegetation, rapid stolonization and increase of virusfree minitubers productivity.

Laser Doppler Flowmetry and Laser Speckle Contrast Imaging are applied usually for assessment of parameters of the cutaneous blood flow during thermoregulation. Alternatively, this work explores the feasibility of blood pulsation imaging under incoherent green illumination for measuring the response of human body on local thermal impact. The proposed technique allows assessment of the cutaneous blood flow changes during thermoregulation simultaneously in different areas of the body. The experiment was conducted in two stages. The first stage is the introduction of tissue into a stressful state (cooling) and observation of its thermoregulation to the normal state. At the second stage, the tissue was heated up from the external heat source. It is found that, the blood pulsation increase in the preliminary cooled tissue is higher by 30-60% in comparison with that one obtained when the tissue was heated. It is shown that, the rate of blood pulsation amplitude increase of pre-cooled tissue is individual characteristic of a subject, while it is less depended on the subject's personal characteristicsin the case of tissue heating.

We present laser microweight biosensor based on the adaptive holographic interferometer. The sensing element of the sensor is gold coated silicon microcantilever with dimensions of 210×40×5 μm³. Biomolecules of the interest being attached to the cantilever increase its mass which in its turn leads to decreasing the cantilever resonance frequency. The frequency shift of the detected signal is directly proportional to the total mass of adsorbed molecules. Cantilever oscillations are detected by the adaptive holographic interferometer based on two-wave mixing in a photorefractive CdTe crystal. For measuring the concentration of biological molecules dissolved in water the cantilever was installed in a cuvette which contains the solution. In the experiment, adsorbed molecules of BSA (Bovine Serum Albumin) with total mass of 3.1 ng were detected and weighted.

Dendrimeric rhodamine-derived chemosensor (POSS-Rh8) for highly selective determination of Au in aqueous acidic solutions has been developed. The response mechanism is based on the catalytic destruction of the dendrimeric molecule what provide fluorescence enhancement via reducing intramolecular quenching. The probe exhibits linear signal response and allows determination of Au content in aqueous solutions from 2·10^-7 M.

The limit of detection for Mg, Mn, Sr, B was experimentally investigated depending on the laser pulse repetition rate in the time resolved femtosecond LIBS. Optical breakdown on the surface of aqueous solutions was generated by the femtosecond Ti:Sa laser with the following parameters: central wavelength - 800 nm, pulse width - 60 fs, pulse energy - 1 mJ, repetition rate 50 Hz, 166 Hz, 250 Hz, 500 Hz, 1000 Hz. The best limit of detection was obtained for the 166 Hz laser repetition rate and for the following elements Mg I (285.2 nm), Mn I (403 nm, 403.3 nm), B I (283.2 nm), Sr I (460.7 nm) are 0.058, 0.025, 1.13, 4.69^-3 mg/kg respectively.

Quantitative and qualitative determination of metal ions is essential for a number of applications in life sciences and environmental monitoring. Optical and, namely, luminescent sensing allows non-invasive measurements within parallel monitoring of multiple samples. A wide variety of luminescent sensing probes using ion-sensitive indicators have been developed for sensing, imaging, and biomedical applications. Here we report a new sensitive element based on excitation energy transfer from donor (rhodamine 6G derivate) to acceptor (microalgae). The concepts and advantages of rhodamine-to-microalgae energy transfer-based sensor systems were highlighted.

The waveguide-based SPR refractometer is studied using state-of-the-art photonic simulation software based on eigenmode expansion method. Two distinct coupling regimes between the waveguide mode and surface plasmon mode are identified. Operating the refractometer in different spectral ranges to measure different values of the ambient refractive index is considered and its metrological performance under different modes of operation is assessed.

The spectral and temporal characteristics of plasma radiation generated by a Ti:Sa femtosecond laser pulses on the surface of Ca aqueous solutions are investigated. Optimum parameters of laser radiation and signal registration are determined to improve the metrological characteristics of time-resolved femtosecond laser induced breakdown spectroscopy.

The possibility of recording weak seismic waves using fiber-optic accelerometers placed on the ice cover is considered. The results of experimental studies of a fiber-optic accelerometer with a threshold sensitivity 10^-7 m/s² are presented. This experiment was held in winter in the Amur Bay (Sea of Japan). The results of recording seismic signals propagating in the ice cover during the motion of objects on ice are presented. The results of recording weak seismic signals propagating in the ice cover during the operation of a low-frequency hydroacoustic emitter are presented. The obtained results prove the possibility of using the presented fiber-optic accelerometer for recording weak seismic waves propagating in the ice cover to solve seismic monitoring problems in the Arctic offshore.

The method of laser induced breakdown spectroscopy (LIBS) was used to investigate intensive lines of sodium, calcium, potassium and magnesium in the aqueous solutions under the action of ultrasound at the frequencies of 10.7 kHz, 60 and 240 kHz. Acoustic radiation was generated within of cylinder transducers using a digital generator and powerful amplifier with maximum amplitude of 100 kPa. To excite optical breakdown in water we used a Nd:YAG laser with the wavelength of 532 and 1064nm. The changing of the delay of the control pulses allows to synchronize the time of maximum expansion of the liquid acoustic impulses and the start of the optical breakdown. The additional influence of ultrasonic radiation on the process of laser breakdown was studied. The increasing of the lines intensity under the influence of ultrasound is observed at all concentrations of the used solutions. It is shown that under the action of ultrasound on the dynamics of the cavity in a fluid the phase of the acoustic impact has a great significance. As a result it is shown that under the influence of ultrasound the strong strengthening of the intensity of spectral lines of elements dissolved in aqueous solutions is observed.

This paper presents the results of the analysis of acoustic emission signals registered by using fiber-optic sensors during the propagation of ultrasonic waves in a polymer composite material. Fiber-optical sensors for acoustic emission were constructed according to the scheme of an adaptive holographic interferometer. Unlike piezoelectric sensors, fiber-optic sensors are distributed type sensors. This imposes certain features on the detection of signals in plates in which fiberoptic sensors are embedded. It is established that the difference of the spectrum of acoustic emission signals registered in different directions of wave propagation. The local maximums of the spectrum are determined by the mode of wave propagation in the plate in different directions and the location of fiber-optic sensors.

The challenge with the formation of sparse antenna arrays is to arrange the array elements along the aperture in order to provide a beam pattern with the required characteristics. It is proposed to use Costas arrays to form sparse antenna arrays. The width and shape of the beam pattern formed on the basis of Costas matrices coincide, on average, with the width and shape of the beam pattern of an equidistant planar antenna array. Choosing the size of the Costas matrix makes it possible to provide the required sparsity factor and the concentration coefficient, and the introduction of tapered amplitude distributions controlling the sidelobe level. The concentration coefficient of a sparse antenna array does not practically depend on frequency. Two methods are arrays with high sparse factors, the second one allows forming sparse antenna arrays with low sparse factors.

This article presents a method for automatic estimation of background intensities in the measurement of seawater fluorescence excited by pulsed laser radiation at wavelengths of 355 and 532 nm, and recorded by CCD matrix with an electron-optical converter (EOC). The problem to be solved is the variability of background intensities and background spatial distribution of CCD image caused mainly by EOC, including in the field of registration of useful signal of seawater fluorescence. This required the development of the numerical model that predicts the shape of the background of the entire image depending on the characteristics of the image areas in which the useful signal is not recorded.

A mathematical formulation of a new method of fluid location of the atmosphere (FLA) is proposed. On the basis of instrumental measurements at one or a few monitoring sites and information on atmospheric dynamics (back trajectories of the motion of air parcels) the FLA method makes it possible to estimate the spatial structure of fields of a measured quantity. Results of solution to a problem of estimating the spatial distribution of the volume concentration of a submicron aerosol are presented; these results were obtained during an analysis of photometric measurements in the period of 20132015 at eight AERONET monitoring sites on the territory of Far Eastern region.

The electro-optic tensor functioning is considered for crystals of 3m type symmetry at various crystallographic orientations. The most effective schemes of electro-optical phase control when light passes through the crystal are brought to light. It is shown that due to electro-optic effect the phase difference between ordinary and extraordinary beams changes when light wave passes through the crystal plate and the polarization of output radiation also changes. It is proved that, using electro-optic effect, it is possible to convert the light wave polarization for a wide range of radiation limited only by the transmission spectrum of the crystal. We take as an example the LiNbO₃ crystal and calculate the range of necessary electric fields to provide its functioning in the half and quarter wave plates mode over the wavelength range of 0.4-4.5 μm.

Influence of incoherent background on diffraction divergence of narrow light beams of He-Ne laser with wavelength of 633 nm due to refractive index changes of Fe-doped lithium niobate sample is experimentally studied. Incoherent background is produced by light-emitting diodes (LED´s) of different average wavelengths and laser diode emitting in blue region of visible. It has been experimentally demonstrated that nonlinear diffraction of coherent red beams of He-Ne laser with diameters on full width of half maximum (FWHM) near to 15 - 20 μm may be totally compensated by means of assistance of incoherent background with shorter average wavelengths 455 – 465 nm and even much lower intensity compared with that for coherent beam.

In this work the numerical simulations of the holographic formation of diffractive optical elements for the light beams conversion into Bessel-like ones in polymer-dispersed liquid crystals (PDLCs) are performed. Theoretical model for simulations is based on the solution of the kinetic equations of photopolymerization-diffusion processes of holograms recording in PDLCs by light beams with inhomogeneous amplitude and phase spatial distributions. Kinetics of spatial harmonics of refraction index changings are investigated and it is shown that during the recording process the spatial profile of diffractive optical element is changing from sinusoidal to inharmonic one. This process is also depends on the ratio of the diffusion and photopolymerization processes rates.

The experimental setup for recording dynamic holograms in photorefractive crystal CdTe by IR radiation with several spectral components is developed and built. The results of the dynamic holograms' recording by radiation with two spectral components are presented and discussed.

In this paper, we propose a theoretical model of vectorial two-wave mixing in optically active photorefractive cubic crystals of the point group 23 and 43m in orthogonal geometry. Proposed model takes into account polarization states of coupling waves, their dependence on the location in the crystal, orientation of wave vectors relative to the main crystallographic axes and optical activity of a crystal. Sets of the wave parameters which provide either a maximum efficiency of wave coupling or wave coupling efficiency insensitive to polarization state of signal wave are found with use of proposed model.

Formation of optical vortices by light beams diffraction on holographically formed diffractive optical elements (DOE) in polymer-dispersed liquid crystals (PDLC) is theoretically described. The feature of investigated DOEs is in their special structure designed to convert the incident light fields into Bessel-like. Numerical simulations for the external electric field’s interaction on these DOEs are obtained. Its influence on the light beams conversion efficiency is studied. The possibility to create electrically controllable transformation elements in PDLCs is theoretically justified.

The theoretical analysis of the dynamic holograms efficiency in the transparent nanosuspension is carried out. It was compared the two-wave scheme of the dynamic holography and the four-wave mixing method. The mechanism of optical nonlinearity of the medium is due to the forces operating on the particles of the dispersed phase in light field (electrostrictive nonlinearity). The peculiarities of the kinetics of the both nonlinear processes were discussed. The results are relevant for dynamic holography in the nanosuspension, as well as for optical diagnostics of such media.

A robotic laser technological complex has been used for the laser powder fusing (LPF) of samarium (Sm) and iron (Fe) powders on stainless steel (SS) substrate in argon flow conditions for the creation of thick (1.0–1.5 mm) ferromagnetic coatings. The formation of Fe–Sm–Ni–Cr and Fe–Cr–Sm alloys was demonstrated on SS substrate due to intensive diffusion of Fe, Cr and Ni atoms from the substrate. A magnetic field (0.2 T) during LPF on the SS substrate resulted in crystallisation of single grains (5–20 microns) of the Fe–Cr–Sm alloy with mutually perpendicular orientation, which were embedded in the Sm–Fe–Ni–Cr alloy matrix and formed a mesh structure in the fused layer. When the additional magnetic field was absent during LPF the larger part of Sm atoms were located in near-surface sample area and around elongated grains, as well as in small grains of spherical form, but dissolution of Sm was blocked in elongated grains. The fused layers from Sm and Fe powders on SS substrates with and without magnetic field had a low coercivity (20–100 Oe), near zero residual magnetisation and high saturation magnetisation (110–112 emu/g) at 300 K. The maximum coercivity (100 Oe) was observed for coating fused with magnetic field, corresponding to mutually perpendicular orientation of ferromagnetic Fe–Cr–Sm grains. The cooling of samples to 4 K resulted in magnetic ordering with a Curie temperature of 50 K and with small changes in coercivity.

A robotic laser technological complex has been used for the laser powder fusing (LPF) of samarium (Sm) and iron (Fe) or Sm and cobalt (Co) powders on duralumin (AMG-3) substrates in argon flow conditions for the creation of thick (0.3–0.5 mm) ferromagnetic coatings. For the Sm-Fe system in the first step of Sm powder laser fusing the chemical interaction between Sm powder and Al atoms from the melted AMG-3 substrate resulted in the formation of Al₂Sm in both cases: with and without perpendicular magnetic field (samples Nos. 6 and 4). The perpendicular magnetic field during LPF on the AMG-3 substrate resulted in the formation of the additional compound Fe₅Al₈ for sample No. 6. The formation of Sm_xFe alloy in the second step of Fe LPF was blocked due to the lower chemical activity of Fe atoms compared to Sm, and the high resistance of Al₂Sm. But for Sm-Co system the interaction between Sm and Co atoms was not blocked and SmCo₅ as a majority crystalline phase was formed. Samples Nos. 4 and 6 based on the Al₂Sm and Fe₅Al₈ compounds were very weak ferromagnetic phases at 300 K with low coercivity, but a strong ferromagnetic ordering with Curie temperature of 70 K was observed at lower temperatures. This ordering increased by 100 times the saturation magnetisation, residual magnetisation and coercivity at 4K. The mechanism of such type of magnetic ordering is not clear at present. The two chopped pieces of the sample No. 5 showed ferromagnetic properties (saturation magnetization of (±27,8 emu/g and ±20.5 emu/g) and coercivities of 130-140 Oe and 300-320 Oe ) that determines only by SmCo₅ grains inside the fused layer. The increase of coercivity for SmCo₅ grains correlates with increase of area of grain boundaries inside the fused layer.

Studies on Young's modulus and microhardness of laser fused surfaces: Sm-Co on the stainless steel and Sm-Fe on the duralumin substrates have shown the heterogeneity of depth properties with local maximum in areas not containing micro cracks. Maximum hardening was obtained for Sm-Fe system. Found that hardening of laser fused layers and the increase their resistance to compression and tension on the stainless steel substrate is associated with the formation of multicomponent alloys (Fe_17.8Ni_25.6Cr_5.6C_11.0Sm_32.1and Fe_64.3Ni_1.9Cr_16.6C_5.5Sm_8.4) due to the diffusion of atoms of the substrate and depends on the availability of the micro crack’s grid of and the alloy microstructure. The high Al diffusion speed from duralumin substrate in the fused layer, formed from Sm powder, and then from Fe powder, led to the segregation of Al on the surface, formation of triple oxide (AlSmO₃) with maximum microhardness and Young's modulus. Further decrease of both parameters is associated with the formation of micro cracks, but a local maximum connects with strong decreasing of microcrack’s density and formation of Al₂Sm layer.

Magnesium has been considered as a new biodegradable material for orthopaedic applications because of its prominent properties including superior biocompatibility, biodegradability, and proper mechanical stiffness. For the direct production of custom biomedical implants, direct laser deposition (DLD) has been applied to fabricate bulk pure magnesium and its resultant properties were studied. Surface morphology, microstructure and mechanical properties of DLD specimen were investigated. The relative porosity of DLD specimen was equal to about 6 %. The microhardness and elasticity modulus of the DLD bulk magnesium were equal to (0.49 ± 0.09) GPa and (30 ± 4) GPa, respectively.