This PDF file contains the front matter associated with SPIE Proceedings Volume 9292, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.
Proc. SPIE 9292, High resolution diode laser spectroscopy of H2O spectra broadened by nitrogen and noble gases, 929202 (25 November 2014); doi: 10.1117/12.2075279
The absorption spectra of pure H2O with mixtures of broadening gases N2, Ar, Xe, He, Ar and air have been measured in 1.39 mμ spectral region by high resolution spectrometer based on diode laser (DFB NEL, Japan). For the processing of pure water spectra and it’s mixtures with a different broadening gases in a wide pressure range we used a multispectrum fitting procedure developed at IAO. The program is based on a relatively simple Rautian-Sobel’man line profile and linear pressure dependence of the line profile parameters. H2O measured spectra bulk processing results in the retrieving of such line parameters: zero-pressure line center positions, intensities, self-broadening and self-shift coefficients of pure water, broadening and shift coefficients for other gases which are describes the experiment with the minimum residuals in a wide pressure range.
The measurements of "isolated" CO2 line (6231.6 cm-1) absorption spectra in wide pressure range from 2 to 1000 mbar
were performed on 3-channel high-resolution diode laser spectrometer. 4 theoretical models used for the description of
lineshape contour: usual Voigt, Hard-collisional (Rautian), Soft-collisional (Galatry), and Speed-dependent Voigt
(Boone). LabView based software used for the testing of current lineshape models. This software performed the
nonlinear least-squares fit of the model spectrum to the experimental spectra recorded at each pressure individually. The
detailed research of weak lines influence to the retrieved parameters of "isolated" CO2 (6231.6 cm-1, R4 band 30013-
00001) is provided. It is shown that the use of Rautian and Galatry lineshape models leads to a significant deviation from
linear of the narrowing coefficient pressure dependence while coming to the high pressures range. Most appropriate for
the common description of whole experimental spectra in entire range of pressures (up to 1000 mbar) is the Speed-
Dependent (Boone) profile.
Proc. SPIE 9292, Theoretical studies of pressure broadened halfwidths of symmetric tops: CH3CN-CH3CN and CH3Cl-CO2 , 929204 (25 November 2014); doi: 10.1117/12.2075328
The semi-empirical method has been used to determine of room temperature self-broadened halfwidths of methyl cyanide and CO2-broadened halfwidths of methyl chloride. We obtained data approximately for 1500 rotation-vibration transitions. J-dependences of these colliding systems are different due to various absorber-perturber resonance effects. Results of calculations clearly demonstrate a very good agreement between observed and computed parameters for both absorbing molecules.
Proc. SPIE 9292, Estimation of uncertainties in the longwave radiative fluxes simulation due to spectroscopic errors, 929205 (25 November 2014); doi: 10.1117/12.2075550
The estimation of errors in the longwave radiative fluxes simulation due to uncertainties in our knowledge of selective and continuum molecular absorption is presented. Modern models of the water vapour continuum absorption and different versions of the HITRAN spectroscopic database (2004, 2008, 2012) are used. It is shown that at present, the major source of the calculation errors in the longwave fluxes at cloudless atmosphere is still an uncertainty in the water vapour continuum absorption coefficients, while the contribution of line parameters’ errors to the simulation is relatively small.
Proc. SPIE 9292, Modelling vibrational-rotational interactions in intensities of v2 band of H2O by Pade approximants, 929206 (25 November 2014); doi: 10.1117/12.2075108
A semiempirical model in the form of Pade approximants, describing vibrational-rotational (VR) interactions in intensities of VR-lines of v2 water vapor (H2O) band, was developed. The corresponding to the C2v molecular symmetry group matrix elements, involved in the expansion of the transformed dipole moment, was applied to the derivation. The treatment of experimental intensities of v2 H2O band for transitions with ΔK = ±1 and ΔK = ±3 by means of obtained model results in decreasing the root mean square deviation (RMS) about two times (2.82 % instead of 6.20 %) in comparison to the traditional scheme.
The results of experimental and theoretical study of the Zeeman splitting of the vibrational-rotational lines in the NO molecule as a function of magnetic field are presented. To record the spectrum the method of laser magnetic resonance (LMR) with using continuous wave frequency-tunable CO laser has been applied. To analyze experimental data of Zeeman splitting, the calculation procedure was developed. This procedure is based on the numerical diagonalization the matrix of the effective molecular Hamiltonian, which includes Zeeman operator corresponding to interaction an external magnetic field with a molecule.
The sulfur dioxide absorption cross sections, measured with a Fourier transform spectrometer at room temperature and varied pressure of SO2-N2 in the 260-330 μm region, are presented. The absorption spectra are obtained at a high spectral resolution of 0.5 cm-1. The measurements results are compared with SO2 cross section data from literature.
Our research into generation of a set of absorption cross sections of atmospheric molecules is reviewed briefly. Particular emphasis is placed on a description of a software toolkit for building information objects that characterize molecules and weakly bound molecular complexes, an application that provides the import and export of the absorption cross sections and representation of metadata and ontolology of information resources collected in a set.
Proc. SPIE 9292, Systematization of published spectral data on sulfur dioxide molecule and its isotopologues , 92920A (25 November 2014); doi: 10.1117/12.2075575
The paper presents a description of properties of published spectral data on spectral lines' parameters of sulfur dioxide
molecule and its isotopologues. These data were acquired from more than 150 publications for a period of 50 years. Data
properties as well as data sources classification according to validity and trust criteria are presented in a form of an
ontological knowledge base on information resources. Data source properties values are computed during the assessment
of validity and trust1. Published ro-vibrational transitions, energy levels, spectral lines' parameters, knowledge base on
information resources of sulfur dioxide molecule and its isotopologues are available in the Internet accessible
information system W@DIS (http://wadis.saga.iao.ru/).
Proc. SPIE 9292, Systematization of published spectral data on deuterated isotopologues of hydrogen sulfide molecule, 92920B (25 November 2014); doi: 10.1117/12.2075976
The report presents a description of properties of published data on spectral lines parameters of deuterated isotopologues of hydrogen sulfide - HDS, HD34S, D2S, D234S. Properties values characterizing data quality are calculated taking into account the validity criteria and credit estimation according to publishing criteria. Formalized criteria of data check based on the constraints and selection rules known from the vibrational-rotational theory, as well as an expert evaluation are utilized for validation of the original experimental transitions and energy levels. The consistent and accurate set of the vibration - rotation (VR) energy levels is derived based on the cleaned transitions. Published vibrational-rotational transitions and energy levels of considered molecules as well as the knowledge base are available in the Internet in W@DIS information system (IS).
An ontological description of molecular states and transitions for quantitative spectroscopy is given wherein states and transitions with certain quantum numbers are characterized by all published values of the physical quantities related to six spectroscopic tasks. Sets of statements appearing in the description of states and transitions are examined, and the number of statements employed in descriptions of different types is estimated.
The authors have studied the radiation transfer in multilayer atmosphere. The analytical formulae for the calculation of the transmission coefficient, reflectance and absorption of dispersion media consisting of three plane layers were obtained. It was shown that absorption of dispersed media depends strongly on absorption layer’s position in dispersed media. The lowest value is marked when the layer takes place below of the media the light falls from above. Investigation of the radiation balance of the atmosphere is usually conducted on the basis of the theory of radiative transfer and numerical methods [1]. In conducting research using various models of the atmosphere [2-4]. Accuracy of the results depends on the accuracy of the approximation and taking into account all the effects that significantly affect the results, such as the effect of the spatial limitations of the dispersion medium [4-6].
The authors have considered the radiation transfer in triple dispersion media with reflective surface. The analytic for determining the values of reflectance and transmission coefficient of atmosphere consisting of three plane layers limited by the reflective surface were obtained. It was shown that stratosphere and bottom atmospheric layers even at low value of optical density and its weak change impact considerably the reflectance of the «triple dispersion media – reflective surface» at all magnitudes of substrate on reflectivity. It was ascertained that the increase of elongation degree phase function in a cloud layer results reflectivity of the whole dispersion media. This effect is similar to reduction of optical density of atmosphere cloud layer.
A line-by-line calculation of the continuum absorption coefficient in the 1600 and 3600 cm-1 water vapor bands with the line wing shape corresponding to asymptotic line shape theory is presented. The calculation results agree closely with quasi-bound dimer absorption estimates made in the context of a dimer hypothesis. An examination of the classical part of the problem at hand enables the fraction of the quasi-bound dimers to be estimated.
Proc. SPIE 9292, A description of the H2O absorption in the 3−5 μm spectral region in violation of the long-wave approximation in line wings, 92920G (25 November 2014); doi: 10.1117/12.2075005
The self-broadened H2O continuum absorption data for the 3−5 μm window available in the literature are described in the framework of asymptotic line wing theory. Use is made of a diffusion model taking into account violation of the long-wave approximation in spectral line wings.
Factors influencing the determination of the continuum absorption have been assessed, using the 4.3 μm CO2 band as an example. The local contribution to the total absorption plays a primary role in the case where the continuum absorption is obtained from experiment. The continuum absorption may be found unambiguously from absorption measurements in band wings. For measurements within the bands, the local contribution can be calculated as the difference between the total measured coefficient and the continuum contribution obtained from measurements in band wings.
Proc. SPIE 9292, Spectral linelist of HD16O molecule based on VTT calculations for atmospheric application , 92920I (25 November 2014); doi: 10.1117/12.2075249
Three version line-list of dipole transition for isotopic modification of water molecule HD16O are presented. Line-lists have been created on the basis of VTT calculations (Voronin, Tennyson, Tolchenov et al. MNRAS, 2010) by adding air- and self-broadening coefficient, and temperature exponents for HD16O-air case. Three cut-of values for the line intensities were used: 1e-30, 1e-32 and 1e-35 cm/molecule. Calculated line-lists are available on the site ftp://ftp.iao.ru/pub/VTT/VTT-296/.
In this paper we present the results of Н216О absorption spectrum investigation recorded by a high resolution Fouriertransform spectrometer IFS-125M in the region 15500 – 16000 cm-1. Absorption path of 34.8 m and resolution of 0.03 см-1 were chosen to record the spectrum. White type multipass absorption cell with a basic length of 60 cm were used. Light-emitting diode (LED) was applied as a source of radiation. Signal-to-noise ratio is about 104, making it possible to measure parameters of lines with intensity up to 2*10-27 cm/molecule. Least-square-fitting algorithm was used to retrieve of the spectroscopic parameters from measured spectral data set. Spectral line positions and line intensities derived from the fitting were compared to data obtained in previous works.
Proc. SPIE 9292, H216O absorption spectrum between 22250 and 22800 cm-1: Fourier transform spectroscopy with bright light source, 92920K (25 November 2014); doi: 10.1117/12.2075383
Measurements of water vapor absorption spectra in the visible spectral region near 0.44 mkm are performed using FTspectrometer IFS-125M and Light-emitting diode (LED) as source of radiation. Water vapor spectrum has been obtained by averaging over 17136 scans recorded at 34,8 m optical path length, temperature 24 ± 1 С and pressure of sample 24,8 mBar. Due to strong emission of LED source it was possible to achieve signal-to-noise ratio about 104 and to record weak lines with intensities of 6 10-27 cm/molecule. Comparisons with results of early works are made.
Proc. SPIE 9292, On effects of isolated cloud on irradiance at the Earth’s surface in the range of 0.4-0.7 μm: results of numerical simulation, 92920L (25 November 2014); doi: 10.1117/12.2074771
We consider the algorithm and results of numerical simulation of irradiance at the Earth’s surface E in the spectral range of 0.4-0.7 μm in the aerosol-molecular atmosphere and in the presence of isolated cloud. We analyze the differences in the irradiance E in the clear-sky and little cloudy atmosphere in dependence of optical and geometrical parameters of cloud, its position relative to the receiver and the illumination conditions.
The method to the calculation of rotation-vibrational line half-width of asymmetric top molecules is proposed. The influence of the buffer gas on the internal state of the absorbing molecule is emphasized in this method. The basic expressions of present approach are given. The averaged energy differences method was used for the calculation of H2O and HDO lines broadening. Comparisons of the calculated line shape parameters with the experimental values in different absorption bands are made.
The D2O absorption spectra adsorbed on the nanoporous airgel SiO2 walls in the spectral range 4200 ... 5400 cm-1 are recorded. Two types of sample with pores of 60 nm wide - the nitrogen gas-treated and untreated airgels were examined. The untreated sample was prolonged evacuation and filling by the D2O saturated vapor. The nitrogen gas-treated sample was short-time pumping, accompanied by treatment with dry nitrogen, and re- lapping by the saturated vapor. As a result, the recorded absorption spectra were shown the changes the hydrophilic properties of the nanopores walls by modernity surface in the presence of nitrogen.
The absorption spectra of the D2О monomer in 3600…4200 cm-1 were recorded using Fourier Transform spectrometer FS-125M at room temperature and pressure of 15 and 33 mbar with spectral resolution of 0.03 cm-1 using 2.5 cm long absorption cell. Strong unblended D2O lines lying on the wing of the H2O stretching band were used to determine the line broadening parameters. They were determined from the line profile by Program VxpProfile. The differences between fitted line profiles and experimental ones do not exceed 2%. Registered D2O lines belong to (011) - (000) and (110) - (000) bands of the second triad. Self-broadening coefficients vary from 0.27 cm-1/atm to 0.445 cm-1/atm and they exceed 3 times the D2O-N2 line broadening coefficients in the v3. Calculations of self-broadening coefficients of the D2O lines were performed using semiempirical method based on the impact theory of broadening and included the correction factors. The calculated results well agree with experimental data.
Proc. SPIE 9292, On the vibrational dependence of the quantum intermolecular interaction potential
, 92920P (25 November 2014); doi: 10.1117/12.2075417
The vibrational dependence of the Н2О-N2 interaction potential due to the line shifts and line wing absorption in the 3−5 μm region is discussed. Evidence in favor of the vibrational dependence of the repulsive part of the potential is given.
Statistical characteristics of the vortex laser beams propagating in the turbulent atmosphere are analyzed. The vortex beams are appeared to be less affected by turbulence as compared with the conventional beams: for the vortex beam the variance of random displacements and the variance for fluctuations of the orbital angular momentum, which are induced by atmospheric turbulence less than these characteristics for the vortexless beam, beams having a larger topological charge are founded to be more stable.
The results obtained from both atmospheric and laboratory experiment and from LES data show that, in the stably stratified flows of the atmospheric boundary layer, turbulent mixing occurs at gradient Richardson number that significantly exceed one: the inverse turbulent Prandtl number decreases with an increase in the thermal stability. The decreasing trend of the inverse turbulent Prandtl number is reproduced in a stably stratified planetary boundary layer in agreement with measurement data with aid of the high closure RANS turbulence scheme, which takes into account the influence of internal gravity waves on the eddy mixing of momentum and heat. Applicability of such RANS turbulence approach for the estimate of eddy diffusivities of momentum and heat in the upper troposphere and lower stratosphere also examined. It is concluded that the high closure RANS turbulence scheme shows the good agreement with the direct measurement data of eddy diffusivities for momentum and heat in the upper troposphere and lower stratosphere during clear-air conditions.
Proc. SPIE 9292, The effect of multiple scattering on polarization and angular distributions for radiation reflected by clouds: results of Monte Carlo simulation , 92920S (25 November 2014); doi: 10.1117/12.2074418
In this paper we study the light scattering in water-drop clouds for various distributions of droplet size. Polarization and angular distributions are simulated by Monte Carlo method for radiation reflected by cloud layers. Computational results make it possible to develop procedures for analyzing the microphysical structure of clouds.
The results of investigations of small-scale atmospheric turbulence are discussed. The differences of the shapes of smallscale atmospheric turbulence spectra in the free atmosphere and the boundary layer are in the focus of the paper. The obtained results may allow us to estimate the characteristics of small-scale (optical) atmospheric turbulence parameters and adaptive optics systems.
Proc. SPIE 9292, Simulation of coherent structures (topological solitons) indoors by numerical solving of hydrodynamics equations, 92920U (25 November 2014); doi: 10.1117/12.2075565
Coherent structures (topological solitons) indoors had been simulated by numerical solving of hydrodynamics equations. "Indoors" means inside the closed volume without the external direct wind influence and without the exchange of internal and external medium through the borders. Results of six boundary value problems are demonstrated: spectrograph pavilion and telescope dome of large astronomical telescopes (LSVT and BTA), cubic room, flat square cuvette, square section tube, parietal turbulence (thermals). The solitary large vortices (coherent structures, topological solitons) are observed indoors. The scenes of air motion as a result of simulation of coherent structures with identical boundary conditions are the practically same as the scenes, independently previously registered at experiments by us (indoors LSVT and BTA).
Last results of experimental researches of the decrease of the light fluctuations in coherent turbulence are presented. Measurements were executed in the autumn of 2013 in a high-mountainous Sayan solar observatory. It is found that astronomical observations are accompanied by periodical transition from the Kolmogorov’s turbulence to coherent turbulence. Such a change of the turbulence type gives intermittency in jitter of the astronomical images.
Efficiency of the adaptive focusing of coherent bunch of radiation is examined in a turbulent atmosphere. The calculation of distributing of middle intensity of the field of coherent laser bunch, focused in a turbulent environment at the use of adaptive phase correction with the use of image of non-coherent source as a supporting source is executed.
On-board enhanced vision system for all-weather aircraft navigation and landing which is currently under development in State research institute of aviation systems is described. The system is based on combination of three imagers sensitive in visible, short wave infrared (SWIR) and long wave infrared (LWIR) spectral ranges and demonstrating to the pilot only the most informative images from the time-aligned multi-sensor data. The results of flight tests at glissade trajectories of the light aircraft АС-5 МР obtained at various weather conditions are presented. It is shown that each spectral range may be informative under certain conditions of observation. In adverse and poor-visibility conditions, such as fog, high humidity and low clouds, SWIR range has the biggest information content.
For the numerical solution of the radiative transfer equation (RTE) it is required its discretization based on the elimination of the solution anisotropic part and the replacement of the scattering integral by a finite sum. Regardless of the particular method of the RTE sampling the boundary value problem for a slab is transformed into the boundary value problem for the matrix inhomogeneous linear differential equation of the first order. The solution of this problem can be represented both through the solution of the homogeneous equation (propagator), and through the scatterers, possessing the property of invariance that leads to the Ambartsumian invariance principle. It is shown that the equivalence of all these approaches can improve the efficiency of the numerical radiative transfer modeling in the turbid medium slab. Significant acceleration of the RTE solution convergence can be achieved by using the method of synthetic iterations.
Proc. SPIE 9292, Photophoretic motion of fractal-like soot aggregates: experiment and theory comparison, 92920Z (25 November 2014); doi: 10.1117/12.2074780
Results of comparison for measured earlier velocities of photophoretic motion of fractal-like soot particles (Karasev et al., 2004) with the theory of photophoresis for spherical homogeneous particles (Beresnev et al., 1993) are presented. It is shown that presented comparison is quite possible, and gives the helpful and rich information for the further development of the rigorous quantitative theory of fractal-like particles photophoresis.
In this work some results of field experiments on the atmospheric optoelectronic communication are considered carried out in spring-summer-fall of 2011–2013. Experiments were aimed at estimation of the feasibility of test information transfer in bistatic communication channels under conditions of cloudless and cloudy atmosphere. The radiation wavelength was 510.6 nm, the length of the communication channel was 17 km.
Review of the authors' works devoted to research of properties of high-temperature gas mixtures and advancement of methods of a remote diagnosis of their optical and physical characteristics is presented. Results of the formation of the informational resource on mathematical, spectroscopic, software and hardware support of passive and active remote sensing techniques of gas-aerosol media are discussed.
Proc. SPIE 9292, Direction and movement angular velocity determining of cloudiness with panoramic images of the sky, 929212 (25 November 2014); doi: 10.1117/12.2074811
This article gives a short overview to method of direction determining and visible angular velocity of movement determining of cloudiness based on set of panoramic images of cloudy sky, obtained by “Fisheye” wide-angle lens.
Proc. SPIE 9292, Analysis of efficiency of the correlation algorithm calculating the speed of the cross wind transfer of the turbulence
by data of Shack-Hartmann sensor
, 929213 (25 November 2014); doi: 10.1117/12.2075003
The results of the correlation analysis of the effectiveness of the algorithm that computes the cross components of wind speed measurements of the wavefront sensor Shack-Hartmann, depending on the intensity of turbulent distortions of the optical parameters of the sensor, the characteristics of the radiation is presented.
This paper presents the results of experimental studies of the properties of the flame in the mid-IR range. Transmittances defined flame for different spectral intervals research shows relationship between the recorded radiance of the flame shielded object and its true characteristics.
Proc. SPIE 9292, Choice for research spectral response of combustion processes using the method of IR diagnostics, 929215 (25 November 2014); doi: 10.1117/12.2074710
This paper presents the emission spectra of the flame produced by combustion of various fuels, provides the rationale for the applicability of various narrow spectral intervals in the range of 2-5 μm for registration problems of temperature fields in the flame and flame shielded registering objects.
Proc. SPIE 9292, Nonequilibrium statistics of the laser beam intensity profile at the output of a model channel with strong turbulence, 929216 (25 November 2014); doi: 10.1117/12.2075595
The experimentally obtained space-time distortions of the signal beam profile in the optical data transmitting channels are presented. Interpretation and prognostication of distortion structure was carried out using the non-equilibrium thermodynamics and statistics methods, particularly non-extensive Renyi entropy. The method of media state operational control using a single sampling frame is proposed.
Proc. SPIE 9292, Spectral composition of inhomogeneities of intensity of laser beam translucent the supersonic jet near the nozzle, 929217 (25 November 2014); doi: 10.1117/12.2074769
The analysis of results of experiments on laser transillumination of the flooded supersonic jet on the wind tunnel of Institute of theoretical and applied mechanics SB RAS is fulfilled. The time spectra of fluctuations of the received power at different values of pressure in the chamber as well as the transformation of the spectra for the initial part of the jet with increasing distance from the nozzle are discussed. The change in the slope of the high-frequency part of the spectrum when lifting beam above the nozzle is demonstrated. Local maxima of the spectral density at frequencies corresponding to the discrete frequencies of acoustic tones generated by the stream are found.
Proc. SPIE 9292, Effect of the initial field’s phase dislocation on the intensity enhancement factor of the laser beam backscattered off a diffuse target, 929218 (25 November 2014); doi: 10.1117/12.2075172
The given article presents the results of the investigation of the vortex laser beam reflection off a diffuse target in turbulent medium. Expressions of the mutual coherence function (MCF) and the relative intensity enhancement factor (REF) of a laser beam at the receiver plane are derived. The effect of the initial phase dislocation in the laser field distribution on the MCF and the REF of a backward wave at the receiver plane is investigated.
Proc. SPIE 9292, Comparison of the ray-tracing and beam-tracing methods in the problem of light scattering by ice crystals of cirrus clouds, 929219 (25 November 2014); doi: 10.1117/12.2075549
Comparison of two approaches within the framework of geometric optics, called the ray-tracing and beam-tracing methods, is considered in application to the problem of light scattering by ice crystal particles of cirrus clouds. A good conformity between the numerical data obtained by these algorithms is demonstrated. The computer time spent for the calculations by these algorithms is analyzed depending on spatial orientations of the particles. It is shown that the beamtracing methods exceeds its counterpart at small number of reflection/refraction events (up to 5) while the situation becomes opposite if this number is larger than 5.
Proc. SPIE 9292, Extremal localization of optical field near surface of spherical dielectric microparticles, 92921A (25 November 2014); doi: 10.1117/12.2075285
The possibility of ultrahigh localization of the optical field near micrometer-sized spherical dielectric particles (zone of “photonic jet”) excited by the pulsed laser radiation is studied theoretically. It is shown for the first time that the photonic jet formed at the nonstationary de-excitation of high-Q resonance modes of a particle can have the sub-diffraction crossdimensional size.
The experimental results of the filamentation terawatt femtosecond Ti:Sapphire-laser along an atmospheric path of 100- m length atmospheric path using different spatial focusing and pulse power. The high efficiency of controlling the position and length of the filamentation zone using various spatial focusing are presented. The dependences of the length and position of the filamentation of the initial degree of focus and pulse power, number of filaments along the filamentation zone is determined. The data are compared to the length of the field and the number of filaments filamentation with the results of our earlier experiments.
Proc. SPIE 9292, Spatial characteristics of the gigawatt laser pulses filamentation area at their different focusing on atmospheric path
, 92921C (25 November 2014); doi: 10.1117/12.2075613
Experimental results on the position and length control of the femtosecond laser pulses filamentation area on the atmospheric path of 30 m length using a different initial spatial focusing are presented. The dependence on the filamentation area length of numerical beam aperture value was obtained. Obtained data comparison on filamentation area length and quantity of filaments with previously conducted experiments results and the other authors’ data carried out.
The results of experimental studies of filamentation of femtosecond laser pulses in water is presented. Measured the number of filaments, the spectral width of the laser radiation, nonlinear focusing distance, the diameter of the field of filamentation power laser pulses. Noted the existence of plot on the scale of the relative power in passing which the explosive growth in the number of filaments.
Proc. SPIE 9292, A numerical simulation method for laser radiation propagating through large-scale atmospheric inhomogeneities, 92921E (25 November 2014); doi: 10.1117/12.2075145
A new approach is suggested to the numerical simulation of laser beam propagation through large-scale atmospheric inhomogeneities. Within this approach, the propagation medium is represented as a continuous 3D distribution of largescale inhomogeneities and a set of common 2D phase screens. A new highly effective simulation method with accounting for the effect of large-scale inhomogeneities is suggested within the aberration-free approximation. It is shown that experimentally observed large-scale inhomogeneities can strongly affect long-distance radiation propagation.
Proc. SPIE 9292, Determination of atmospheric turbulent inhomogeneity wind drift from sequence of incoherent images, 92921F (25 November 2014); doi: 10.1117/12.2075640
An effect of turbulent inhomogeneities, differently distant from an observer, on distortions of atmospheric object images is analyzed on the basis of numerical simulation. A technique for determining the atmospheric inhomogeneity wind drift from sequence of images of an object specified is suggested. A capability of the technique of determining the atmospheric inhomogeneity wind drift from two images is shown.
Researches of coherent properties of the vortex Bessel optical beams propagating in turbulent atmosphere are theoretically developed. The degree of coherence of vortex Bessel optical beams depending on beam parameters (crosssection wave number and a topological charge) and characteristics of turbulent atmosphere is in details analysed. It is shown, that at low levels of fluctuations in turbulent atmosphere, the degree of coherence of a vortex Bessel optical beam essentially depends on value of a topological charge of a beam. In the central part of a two-dimensional field of degree of coherence the ring dislocations, which number of rings to equally value of a topological charge of a vortex optical beam, is formed. At high levels of fluctuations in turbulent atmosphere, the degree of coherence of a vortex Bessel beam decreases much faster, than it takes place for the fundamental Bessel beam. And, speed of decrease essentially increases in process of growth of value of a topological charge of a beam.
The passive differential method of measuring of maintenance in the atmosphere of atoms of sodium is offered in a mesosphere with the use of solar radiation. With sufficient good exactness relation of irradiances of the Sun on two near, such that aerosol dispersion and weakening practically identically, wavelengths equal as (λ1/λ2 ))5 . On the basis of analysis of relation of irradiances of a Sun on two wavelengths it is possible to determine the relative changes of maintenance of atoms of sodium in the whole atmospheric colomn.
Proc. SPIE 9292, Formation of "photonic jet" upon irradiation of spherical microparticles by a focused laser beam, 92921I (25 November 2014); doi: 10.1117/12.2075284
Features of formation "photonic nanojets" (PNJs) near the surface of spherical dielectric microparticles irradiated by a spatially limited laser beam are theoretically investigated. The influence of the waist size of a light beam with the Gaussian transverse intensity profile on PNJ spatial parameters and peak intensity is found for the first time.
Proc. SPIE 9292, Influence of regular and random distortions on quality of multichannel laser radiation, 92921J (25 November 2014); doi: 10.1117/12.2075154
In the paper the results of simulation are presented of multichannel laser radiation propagation under conditions of free diffraction. Influence of distortions developed in channels on effectiveness of energy transfer is also considered. It was shown that with increase of channel number the influence of random tilts and piston-type aberration decreased.
discrete scattering medium with particles large in comparison with length of a wave of optical radiation is deduced. Conditions at which fulfil the integral equation transform into the differential equation are resulted. In that specific case of vortex Gaussian beams the solution of this differential equation is derived. Possibilities of carrying over of an optical vortex on lengthy path in the presence of discrete scatterings in atmosphere are discussed.
Proc. SPIE 9292, Spatial coherence and mean intensity of backscattered short-pulse optical radiation , 92921L (25 November 2014); doi: 10.1117/12.2074662
The function of mutual coherence of the field and the mean intensity of partially coherent pulsed optical radiation scattered by an atmospheric layer have been calculated. It is shown that as the pulse duration decreases, the spatial coherence of backscattered radiation improves in comparison with the coherence of scattered continuous-wave (cw) radiation. In contrast to cw radiation, which scatters uniformly in the backward direction, the backscattering of pulsed radiation becomes nonuniform for shorter pulses, and for ultrashort pulse durations the backscattered radiation is localized near the strictly backward direction in the zone with transverse dimensions comparable with the initial size of the sensing beam.