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Sample records for rayleigh light scattering

  1. Rayleigh Scattering.

    ERIC Educational Resources Information Center

    Young, Andrew T.

    1982-01-01

    The correct usage of such terminology as "Rayleigh scattering,""Rayleigh lines,""Raman lines," and "Tyndall scattering" is resolved during an historical excursion through the physics of light-scattering by gas molecules. (Author/JN)

  2. POLARIZED LIGHT REFLECTED AND TRANSMITTED BY THICK RAYLEIGH SCATTERING ATMOSPHERES

    SciTech Connect

    Natraj, Vijay; Hovenier, J. W.

    2012-03-20

    Accurate values for the intensity and polarization of light reflected and transmitted by optically thick Rayleigh scattering atmospheres with a Lambert surface underneath are presented. A recently reported new method for solving integral equations describing Chandrasekhar's X- and Y-functions is used. The results have been validated using various tests and techniques, including the doubling-adding method, and are accurate to within one unit in the eighth decimal place. Tables are stored electronically and expected to be useful as benchmark results for the (exo)planetary science and astrophysics communities. Asymptotic expressions to obtain Stokes parameters for a thick layer from those of a semi-infinite atmosphere are also provided.

  3. Rayleigh Light Scattering from Nematic Liquid Crystals at Oblique Incidence.

    NASA Astrophysics Data System (ADS)

    da, Xiao-Yi.

    Ryuichi Akiyama 1980 and his co-workers first showed the possibility that light scattering experiments on nematic liquid crystals could be carried out preferably by using oblique incidence rather than the conventional normal incidence. Miraldi, et al 1980 strongly recommended the application of oblique incidence, and gave a discussion in detail. The present work starts from an attempt to obtain the three Frank elastic constants and viscosity coefficients of nematic liquid crystals by Rayleigh light scattering. A suitable scattering geometry has been chosen; a systematic method of measuring these constants and coefficients has been developed by measuring the linewidths of the scattered light from a single sample at various incidence angles and fitting the measured linewidths with appropriate theoretical expressions. It is shown in the present work that the light scattering experiments on nematic liquid crystals at oblique incidence have many advantages over the same kind of experiments at normal incidence so far widely employed, and show a promising future. After a brief introduction to the general theory of the dynamic light scattering, nematic liquid crystals and light scattering from nematic liquid crystals in Chapters 1, 2, and 3, and a brief review of the measurements of elastic constants and viscosity coefficients of nematic liquid crystals by light scattering in Chapter 4, a straightforward method concerning the calculation of variations of the wave vectors upon scattering is developed in Chapter 5. This method assumes that a nematic liquid crystal behaves optically like a uniaxial crystal. In doing so, all we have to know is the ordinary and extraordinary refractive indices n(,o) and n(,e) of the sample under consideration. The linewidth and intensity distributions of the scattered light can then be determined by inserting the variations in wave vectors into appropriate equations for a known material for which the knowledge of the elastic constants as well

  4. Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

    2008-01-01

    This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

  5. Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering.

    PubMed

    Antoun, Ayman; Pavlov, Michael Y.; Tenson, Tanel; Ehrenberg M, M åNs

    2004-01-01

    Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix. PMID:15103398

  6. Interferometric Rayleigh Scattering Measurement System

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel (Inventor); Danehy, Paul M. (Inventor); Lee, Joseph W. (Inventor)

    2008-01-01

    A method and apparatus for performing simultaneous multi-point measurements of multiple velocity components in a gas flow is described. Pulses of laser light are directed to a measurement region of unseeded gas to produce Rayleigh or Mie scattered light in a plurality of directions. The Rayleigh or Mie scattered light is collected from multiple directions and combined in a single collimated light beam. The Rayleigh or Mie scattered light is then mixed together with a reference laser light before it is passed through a single planar Fabry-Perot interferometer for spectral analysis. At the output of the interferometer, a high-sensitivity CCD camera images the interference fringe pattern. This pattern contains the spectral and spatial information from both the Rayleigh scattered light and the reference laser light. Interferogram processing software extracts and analyzes spectral profiles to determine the velocity components of the gas flow at multiple points in the measurement region. The Rayleigh light rejected by the interferometer is recirculated to increase the accuracy and the applicability of the method for measurements at high temperatures without requiring an increase in the laser energy.

  7. Rayleigh Scattering Diagnostics Workshop

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard (Compiler)

    1996-01-01

    The Rayleigh Scattering Diagnostics Workshop was held July 25-26, 1995 at the NASA Lewis Research Center in Cleveland, Ohio. The purpose of the workshop was to foster timely exchange of information and expertise acquired by researchers and users of laser based Rayleigh scattering diagnostics for aerospace flow facilities and other applications. This Conference Publication includes the 12 technical presentations and transcriptions of the two panel discussions. The first panel was made up of 'users' of optical diagnostics, mainly in aerospace test facilities, and its purpose was to assess areas of potential applications of Rayleigh scattering diagnostics. The second panel was made up of active researchers in Rayleigh scattering diagnostics, and its purpose was to discuss the direction of future work.

  8. Development of a noninvasive diabetes screening device using the ratio of fluorescence to Rayleigh scattered light

    NASA Astrophysics Data System (ADS)

    Yu, Nai-Teng; Krantz, Brian S.; Eppstein, Jonathan A.; Ignotz, Keith D.; Samuels, Mark A.; Long, James R.; Price, John

    1996-07-01

    We have developed a new lens measurement system that simultaneously measures the intensities of fluorescence and Rayleigh components at various distances into the lens along the optical axis. The noninvasive measurement is performed through an undilated pupil, and with the assistance of a pupil tracking system that facilitates maintaining the x and y positions of the sample volume to within +/- 100 micrometers of any programmed 'lock' position. The intensity of the Rayleigh component that is used to normalize the measured fluorescent signal serves to correct the attenuation effects due to absorption and lens light scatter. This report, resulting from a SpectRx Site L clinical study using a refined instrumentation, presents analysis of fluorescence and Rayleigh data from the lenses of 923 controls and 239 diabetic subjects ranging from 23 to 75 years old. Fluorescence and Rayleigh data have been obtained via confocal mode from various locations nominally along the lens optical axis for controls and diabetics, at different ages, using three pairs of excitation and collection wavelengths: 364/495 nm, 434/495 nm, and 485/515 nm. For control subjects, there exists a strong, almost linear relationship between age and fluorescence, while diabetic subjects tend to deviate from this age-fluorescence relationship. Our data show that the lenses of diabetic patients are subject to an accelerated aging process, presumably due to an elevated level of brown and fluorescence protein adducts and crosslinks from nonenzymatic glycosylation. We have also shown that by using the measured Rayleigh profiles to normalize the measured fluorescence, most of the absorption effects are removed and therefore the separation between the fluorescence of diabetics and controls is greatly improved. Thus, the device for measuring fluorescence/Rayleigh ratios can be used to noninvasively screen populations for possible undiagnosed diabetes.

  9. Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry air, and moist air.

    PubMed

    Witschas, Benjamin; Vieitez, Maria O; van Duijn, Eric-Jan; Reitebuch, Oliver; van de Water, Willem; Ubachs, Wim

    2010-08-01

    Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh-Brillouin scattering measurements in the ultraviolet at a scattering angle of 90 degrees on N(2) and on dry and moist air. The measured line shapes are compared to the Tenti S6 model, which is shown to describe the scattering line shapes in air at atmospheric pressures with small but significant deviations. We demonstrate that the line profiles of N(2) and air under equal pressure and temperature conditions differ significantly, and that this difference can be described by the S6 model. Moreover, we show that even a high water vapor content in air up to a volume fraction of 3.6vol.% has no influence on the line shape of the scattered light. The results are of relevance for the future spaceborne lidars on ADM-Aeolus (Atmospheric Dynamics Mission) and EarthCARE (Earth Clouds, Aerosols, and Radiation Explorer). PMID:20676176

  10. Rayleigh's Scattering Revised

    NASA Astrophysics Data System (ADS)

    Kolomiets, Sergey; Gorelik, Andrey

    Mie’s waves while sounding within coincident volumes. Being sensitive to the size of scatters, Mie’s waves can give us additional information about particle size distribution. But how about using several wavelengths corresponding to Rayleigh’s diffraction on scatters only? Can any effects be detected in such a case and what performance characteristics of the equipment are required to detect them? The deceptive simplicity of the negative answer to the first part of the question posed will disappear if one collects different definitions of Rayleigh's scattering and consider them more closely than usually. Several definitions borrowed from the introductory texts and most popular textbooks and articles can be seen as one of the reasons for the research presented in the report. Hopefully, based on the comparison of them all, anyone could easily conclude that Rayleigh's scattering has been analyzed extensively, but despite this extensive analysis made fundamental ambiguities in introductory texts are not eliminated completely to date. Moreover, there may be found unreasonably many examples on how these ambiguities have already caused an error to be foreseen, published on the one article, amplified in another one, then cited with approval in the third one, before being finally corrected. Everything indicated that in the light of all the lesions learned and based on modern experimental data, it is time to address these issues again. After the discussion of ambiguities of Rayleigh's scattering concepts, the development of the corrections to original ideas looks relatively easy. In particular, there may be distinguished at least three characteristic regions of the revised models application from the point of view of the scattered field statistical averaging. The authors of the report suggest naming them Rayleigh’s region, Einstein’s region and the region with compensations of the scattering intensity. The most important fact is that the limits of applicability of all

  11. Interfacing whispering-gallery microresonators and free space light with cavity enhanced Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Zhu, Jiangang; Özdemir, Şahin K.; Yilmaz, Huzeyfe; Peng, Bo; Dong, Mark; Tomes, Matthew; Carmon, Tal; Yang, Lan

    2014-09-01

    Whispering gallery mode resonators (WGMRs) take advantage of strong light confinement and long photon lifetime for applications in sensing, optomechanics, microlasers and quantum optics. However, their rotational symmetry and low radiation loss impede energy exchange between WGMs and the surrounding. As a result, free-space coupling of light into and from WGMRs is very challenging. In previous schemes, resonators are intentionally deformed to break circular symmetry to enable free-space coupling of carefully aligned focused light, which comes with bulky size and alignment issues that hinder the realization of compact WGMR applications. Here, we report a new class of nanocouplers based on cavity enhanced Rayleigh scattering from nano-scatterer(s) on resonator surface, and demonstrate whispering gallery microlaser by free-space optical pumping of an Ytterbium doped silica microtoroid via the scatterers. This new scheme will not only expand the range of applications enabled by WGMRs, but also provide a possible route to integrate them into solar powered green photonics.

  12. Improvement in Rayleigh Scattering Measurement Accuracy

    NASA Technical Reports Server (NTRS)

    Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.

    2012-01-01

    Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous velocity, density, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of an acousto-optic frequency shifting device to improve measurement accuracy in Rayleigh scattering experiments at the NASA Glenn Research Center. The frequency shifting device is used as a means of shifting the incident or reference laser frequency by 1100 MHz to avoid overlap of the Rayleigh and reference signal peaks in the interference pattern used to obtain the velocity, density, and temperature measurements, and also to calibrate the free spectral range of the Fabry-Perot etalon. The measurement accuracy improvement is evaluated by comparison of Rayleigh scattering measurements acquired with and without shifting of the reference signal frequency in a 10 mm diameter subsonic nozzle flow.

  13. Rayleigh light scattering measurements of transient gas temperature in a rapid chemical vapor deposition reactor

    SciTech Connect

    Horton, J.F.; Peterson, J.E.

    2000-02-01

    A laser-induced Rayleigh light scattering (RLS) system was used to measure transient gas temperatures in a simulated rapid chemical vapor deposition (RCVD) reactor. The test section geometry was an axisymmetric jet of carrier gas directed down, impinging on a heated water surface. RLS was used to measure instantaneous gas temperature at several locations above the wafer as it was heated from room temperature to 475 K. Gas flow rate and wafer temperature correspond to jet Reynolds number Re{sub i} = 60, wafer maximum Grashof number Gr{sub H} = 4.4 x 10{sup 6}, and a maximum mixed convection parameter Gr{sub H}/Re{sub i}{sup 2} = 1200; all conditions typical of impinging jet reactors common in the numerical literature. Uncertainty of RLS transient temperature from a propagated error analysis was {+-}2--4 K. Peak gas temperature fluctuations were large (in the order of 25 to 75 C). Both flow visualization and RLS measurements showed that the flow field was momentum dominated prior to heating initiation, but became unstable by Gr{sub H}/Re{sub i}{sup 2} = 5. It then consisted of buoyancy-induced plumes and recirculations. Up to the peak wafer temperature, the flow field continued to be highly three-dimensional, unsteady, and dominated by buoyancy. RLS measurements are shown to provide information on carrier gas instantaneous temperature and flow field stability, both critical issues in RCVD processing.

  14. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Liebl, Michael

    2010-05-01

    The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available.2-5 Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of classroom demonstrations have been described for showing the effects.6-11 This paper describes how these demonstrations can be enhanced by using a spectrometer to measure the preferential scattering of the shorter wavelength light.

  15. Rayleigh light scattering detection of three α1-adrenoceptor antagonists coupled with high performance liquid chromatograph

    NASA Astrophysics Data System (ADS)

    Li, Ai Ping; Peng, Huanjun; Peng, Jing Dong; Zhou, Ming Qiong; Zhang, Jing

    2015-08-01

    Herein, a Rayleigh light-scattering (RLS) detection method combined with high performance liquid chromatograph (HPLC) without any post-column probe was developed for the separation and determination of three α1-adrenoceptor antagonists. The quantitative analysis is benefiting from RLS signal enhancement upon addition of methanol which induced molecular aggregation to form an hydrophobic interface between aggregates and water that produce a sort of superficial enhanced scattering effect. A good chromatographic separation among the compounds was achieved using a Gemini 5u C18 reversed phase column (250 mm × 4.6 mm; 4 μm) with a mobile phase consisting of methanol and ammonium acetate-formic acid buffer solution (25 mM; pH = 3.0) at the flow rate of 0.7 mL min-1. The RLS signal was monitored at λex = λem = 354 nm. A limit of detection (LOD) of 0.065-0.70 μg L-1 was reached and a linear range was found between peak height and concentration in the range of 0.75-15 μg L-1 for doxazosin mesylate (DOX), 0.075-3.0 μg L-1 for prazosin hydrochloride (PRH), and 0.25-5 μg L-1 for terazosin hydrochloride (TEH), with linear regression coefficients all above 0.999. Recoveries from spiked urine samples were 88.4-99.0% which is within acceptable limits. The proposed method is convenient, reliable and sensitive which has been used successfully in human urine samples.

  16. Improvement in Suppression of Pulsed Nd:YAG Laser Light With Iodine Absorption Cells for Filtered Rayleigh Scattering Measurements

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Buggele, Alvin E

    1997-01-01

    Filtered Rayleigh scattering using iodine absorption cells is an effective technique for obtaining density, temperature, and velocity measurements in high speed confined flows. By tuning a single frequency laser to a strong iodine absorption line, stray scattered laser light can be greatly suppressed. For example, the minimum transmission predicted by an iodine absorption model calculation is less than 10(exp -5) at the 18788.44/cm line using a 200 mm absorption cell containing iodine vapor at 0.46 T. Measurements obtained by other researches using a CW Nd:YAG laser agree with the model calculations. However, measurements made by us and by others using Q-switched, injection-seeded, frequency doubled Nd:YAG lasers only show minimum transmission of about 3 x 10(exp -3). This greatly reduces the applicability of the filtered Rayleigh scattering technique using these lasers in experiments having large amounts of stray scattered laser light. The purposes of the present study are to characterize the spectrum of the excess light transmitted by the iodine cell and to make changes to the laser to reduce the transmitted laser light. Transmission data as a function of laser frequency for the iodine absorption line at 18788.44/cm are presented. A planar mirror Fabry-Perot interferometer was used to characterize the frequency spectrum of the light passed through the cell. Measurements taken with the laser tuned to the center of the iodine absorption line show the light transmitted through the iodine cell to have a component with a bandwidth of about 40 GHz. This is probably caused by other modes in the laser that exist in spite of the single frequency injection beam. A second broadband component was also observed, possibly caused by the laser flash lamps or by fluorescence. An intracavity etalon was installed in the laser oscillator cavity to suppress the 40 GHz component. Measurements taken with the etalon tuned to the injection frequency showed a reduction in the transmitted

  17. Decoherence due to Elastic Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Meiser, D.; Ozeri, R.; Bollinger, J. J.

    2010-11-01

    We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of Be+9 in a 4.5 T magnetic field.

  18. Decoherence due to elastic Rayleigh scattering.

    PubMed

    Uys, H; Biercuk, M J; Vandevender, A P; Ospelkaus, C; Meiser, D; Ozeri, R; Bollinger, J J

    2010-11-12

    We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of 9Be+ in a 4.5 T magnetic field. PMID:21231210

  19. Rayleigh scattering of linear alkylbenzene in large liquid scintillator detectors

    SciTech Connect

    Zhou, Xiang Zhang, Zhenyu; Liu, Qian; Zheng, Yangheng; Wurm, Michael; Zhang, Qingmin; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-07-15

    Rayleigh scattering poses an intrinsic limit for the transparency of organic liquid scintillators. This work focuses on the Rayleigh scattering length of linear alkylbenzene (LAB), which will be used as the solvent of the liquid scintillator in the central detector of the Jiangmen Underground Neutrino Observatory. We investigate the anisotropy of the Rayleigh scattering in LAB, showing that the resulting Rayleigh scattering length will be significantly shorter than reported before. Given the same overall light attenuation, this will result in a more efficient transmission of photons through the scintillator, increasing the amount of light collected by the photosensors and thereby the energy resolution of the detector.

  20. Decoherence due to elastic Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Bollinger, J. J.; Meiser, D.

    2010-03-01

    Off-resonant light scattering (spontaneous emission) is an important source of decoherence in many coherent control experiments. Typically one focuses on the effects of Raman scattering, in which an atomic state is changed by a single scattering event. We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of off-resonant light. By a master equation technique we show that for a two-level superposition the elastic decoherence rate is the square of the difference between the two elastic scattering amplitudes. Thus, if the light detunings for the two states have opposite sign, the amplitudes interfere constructively and can result in a large decoherence rate. We calculate and measure the total decoherence rate for a superposition state of the valence electron spin in the ground state of ^9Be^+ in a 4.5 T magnetic field. We find that for large (˜20 GHz) detunings, decoherence due to elastic Rayleigh scattering can be 5 times larger than decoherence due to Raman scattering. This is in contrast with workootnotetextR. Ozeri, et al., PRL 95, 030403 (2005) at low magnetic field where decoherence was dominated by Raman scattering.

  1. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    ERIC Educational Resources Information Center

    Liebl, Michael

    2010-01-01

    The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…

  2. Cellulosic nanowhiskers. Theory and application of light scattering from polydisperse spheroids in the Rayleigh-Gans-Debye regime.

    PubMed

    Braun, Birgit; Dorgan, John R; Chandler, John P

    2008-04-01

    Mathematical treatment of light scattering within the Rayleigh-Gans-Debye limit for spheroids with polydispersity in both length and diameter is developed and experimentally tested using cellulosic nanowhiskers (CNW). Polydispersity indices are obtained by fitting the theoretical formfactor to experimental data. Good agreement is achieved using a polydispersity of 2.3 for the length, independent of the type of acid used. Diameter polydispersities are 2.1 and 3.0 for sulfuric and hydrochloric acids, respectively. These polydispersities allow the determination of average dimensions from the z-average mean-square radius (z) and the weight-average molecular weight (M w) easily obtained from Berry plots. For cotton linter hydrolyzed by hydrochloric acid, the average length and diameter are 244 and 22 nm. This compares to average length and diameter of 272 and 13 nm for sulfuric acid. This study establishes a new light-scattering methodology as a quick and robust tool for size characterization of polydisperse spheroidal nanoparticles. PMID:18357993

  3. Mie and Rayleigh modeling of visible-light scattering in neonatal skin

    NASA Astrophysics Data System (ADS)

    Saidi, Iyad S.; Jacques, Steven L.; Tittel, Frank K.

    1995-11-01

    Reduced-scattering coefficients of neonatal skin were deduced in the 450-750-nm range from integrating-sphere measurements of the total reflection and total transmission of 22 skin samples. The reduced-scattering coefficients increased linearly at each wavelength with gestational maturity. The distribution of diameters d and concentration rho A of the skin-sample collagen fibers were measured in histological sections of nine neonatal skin samples of varying gestational ages. An algorithm that calculates Mie scattering by cylinders was used to model the scattering by the collagen fibers in the skin. The fraction of the reduced-scattering coefficient mu s` that was attributable to Mie scattering by

  4. Light scattering by tenuous particles - A generalization of the Rayleigh-Gans-Rocard approach

    NASA Technical Reports Server (NTRS)

    Acquista, C.

    1976-01-01

    We consider scattering by arbitrarily shaped particles that satisfy two conditions: (1) that the polarizability of the particle relative to the ambient medium be small compared to 1 and (2) that the phase shift introduced by the particle be less than 2. We solve the integro-differential equation proposed by Shifrin by using the method of successive iterations and then applying a Fourier transform. For the second iteration, results are presented that accurately describe scattering by a broad class of particles. The phase function and other elements of the scattering matrix are shown to be in excellent agreement with Mie theory for spherical scatterers.

  5. Heavy metal fluoride glasses with low intrinsic Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Schroeder, J.; Tsoukala, V.; Staller, C. O.; Stiller, M. A.; Bruce, A.; Moynihan, C. T.; Hutta, J. J.; Suscavage, M. J.; Drexhage, M.

    1984-10-01

    The results of Rayleigh light scattering measurements in bulk multicomponent fluorozirconate glasses are described. It is observed for the first time that such materials may be reproducibly prepared with uniformly low scattering levels throughout their volume. In 13 of the 15 specimens studied, the magnitude of the Rayleigh scattering loss was one-third to one-half that typically observed in fused silica glass.

  6. Modeling Rayleigh Scattering of Aerosol Particles.

    PubMed

    Harczuk, Ignat; Vahtras, Olav; Ågren, Hans

    2016-05-12

    Rayleigh scattering of naturally polarized light was studied for systems with atmospheric relevance representing growing water clusters with adsorbed cis-pinonic acid. The scattering intensity was computed from the static and dynamical polarizabilities of the clusters obtained by a recently derived methodology for classical polarizabilities, in which Applequist equations for interacting polarizable dipoles are used together with point-dipoles and polarizabilities obtained by quantum chemistry and decomposed into the atomic domain by the so-called LoProp transformation generalized for frequency dependence. The Applequist interaction was found to yield scattering intensities 20% larger for a cluster consisting of 1000 water molecules, as compared to the method where all of the polarizabilities of molecules are added without interactions. It was confirmed that scattering intensity depends quadratically on the number of water molecules in the cluster, and that it also increases quadratically with increase in the mass constituent of the foreign substance. The adsorption of the cis-pinonic acid increases the contribution to the scattering intensity stemming from the anisotropic polarizability, as compared to the isotropic contribution. The ramifications of the method in predicting Rayleigh scattering and the earth's albedo with respect to man-made and natural gas emission are briefly discussed. PMID:27097131

  7. Collision-induced hyper-Rayleigh light scattering in gaseous dihydrogen-neon mixtures

    SciTech Connect

    Glaz, W.; Bancewicz, T.; Godet, J.-L.; Haskopoulos, A.; Maroulis, G.

    2011-07-15

    Cartesian components of the collision-induced (CI) hyperpolarizability {Delta}{beta} tensor are computed for the linear, T-shaped, and 45 deg. configurations of the H{sub 2}-Ne pair in the intermolecular range 3 to 14 bohr. Symmetry-adapted components {Delta}{beta}{sub {lambda}L}{sup (K)}(R) of the vector (K=1) part, as well as the septor (K=3) part, of the H{sub 2}-Ne CI hyperpolarizability are calculated starting from the ab initio Cartesian hyperpolarizability tensor values transformed into their spherical counterparts. By applying these quantities, the vector together with the septor collision-induced hyper-Rayleigh (CIHR) spectra for the H{sub 2}-Ne binary gas mixture are determined in the frequency range from -1250 to 2500 cm{sup -1}. The profiles are partially employed as a benchmarking device to estimate the importance of the short intermolecular distance part of the {Delta}{beta}(R) dependence. The depolarization ratio of the CIHR spectra in the whole frequency range is also calculated. The nature of the CIHR signal and the feasibility of the related experiments are discussed and analyzed.

  8. NONLINEAR OPTICAL PHENOMENA Frequency shift of Rayleigh line fine structure components in a water solution of 4-methylpyridine as a function of temperature, concentration, and light scattering angle

    NASA Astrophysics Data System (ADS)

    Bunkin, Nikolai F.; Gorelik, Vladimir S.; Sabirov, L. M.; Semenov, D. I.; Khaidarov, Kh S.

    2010-11-01

    The frequency shift Δv of the fine structure components of Rayleigh light scattering in 4-methylpyridine water solutions is studied in the ranges of 1 — 0.1 mole fraction concentrations and temperature 10 — 80 °C. The laws of Δv variation at different light scattering angles are discussed from the viewpoint of solution structural reorganisation under the varying temperature and concentration of nonelectrolyte in water. Existence of a continuous hydrogen-bond net in the solutions is experimentally proved in a certain range of temperatures and concentrations.

  9. Accuracy of RGD approximation for computing light scattering properties of diffusing and motile bacteria. [Rayleigh-Gans-Debye

    NASA Technical Reports Server (NTRS)

    Kottarchyk, M.; Chen, S.-H.; Asano, S.

    1979-01-01

    The study tests the accuracy of the Rayleigh-Gans-Debye (RGD) approximation against a rigorous scattering theory calculation for a simplified model of E. coli (about 1 micron in size) - a solid spheroid. A general procedure is formulated whereby the scattered field amplitude correlation function, for both polarized and depolarized contributions, can be computed for a collection of particles. An explicit formula is presented for the scattered intensity, both polarized and depolarized, for a collection of randomly diffusing or moving particles. Two specific cases for the intermediate scattering functions are considered: diffusing particles and freely moving particles with a Maxwellian speed distribution. The formalism is applied to microorganisms suspended in a liquid medium. Sensitivity studies revealed that for values of the relative index of refraction greater than 1.03, RGD could be in serious error in computing the intensity as well as correlation functions.

  10. Bacterial Light-Harvesting Complexes Showing Giant Second-Order Nonlinear Optical Response as Revealed by Hyper-Rayleigh Light Scattering.

    PubMed

    Ma, Fei; Yu, Long-Jiang; Ma, Xiao-Hua; Wang, Peng; Wang-Otomo, Zheng-Yu; Zhang, Jian-Ping

    2016-09-01

    The second-order nonlinear optical (NLO) properties of light-harvesting complexes (LHs) from the purple photosynthetic bacteria Thermochromatium (Tch.) tepidum were investigated for the first time by means of hyper-Rayleigh scattering (HRS). The carotenoid (Car) molecules bound to the isolated LH1 and LH2 proteins gave rise to second-harmonic scattering; however, they showed an opposite effect of the collective contribution from Car, that is, the first hyperpolarizability (β) reduced substantially from (10 510 ± 370) × 10(-30) esu for LH1 to (360 ± 120) × 10(-30) esu for LH2. Chromatophores of Tch. tepidum also showed a giant hyperpolarizability of (11 640 ± 630) × 10(-30) esu. On the basis of the structural information on bacterial LHs, it is found that the effective β of an LH is governed by the microenvironment and orientational correlation among the Car chromophores, which is concluded to be coherently enhanced for LH1. For LH2, however, additional destructive effects between different Car molecules may account for the small β value. This work demonstrates that LH1 and native membranes of purple bacteria can be potent NLO materials and that HRS is a promising spectroscopic means for investigating structural information of pigment-protein supramolecules. PMID:27505442

  11. Rayleigh Scattering Diagnostic for Dynamic Measurement of Velocity and Temperature

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, J.

    2001-01-01

    A new technique for measuring dynamic gas velocity and temperature is described. The technique is based on molecular Rayleigh scattering of laser light, so no seeding of the flow is necessary. The Rayleigh scattered light is filtered with a fixed cavity, planar mirror Fabry-Perot interferometer. A minimum number of photodetectors were used in order to allow the high data acquisition rate needed for dynamic measurements. One photomultiplier tube (PMT) was used to measure the total Rayleigh scattering, which is proportional to the gas density. Two additional PMTs were used to detect light that passes through two apertures in a mask located in the interferometer fringe plane. An uncertainty analysis was used to select the optimum aperture parameters and to predict the measurement uncertainty due to photon shot-noise. Results of an experiment to measure the velocity of a subsonic free jet are presented.

  12. Anomalous Rayleigh Scattering and Nanoscale Inhomogeneities in Glasses

    NASA Astrophysics Data System (ADS)

    Schroeder, John; Lee, Mierie; Moynihan, Cornelius T.

    2000-03-01

    Light scattering from oxide and halide glasses in the glass transition region exhibits anomalous Rayleigh scattering.We observe a local maximum in the scattered intensity during the heating phase of heating and cooling experiments.It is shown that this behavior is consistent with the presence of nanoscale inhomogeneities,which relax at different rates.Observations of anomalous light scattering were detected from strong and fragile glass formers.In all glasses a hysteresis effect is seen in the Rayleigh scattering behavior when heating and cooling experiments are compared.In the cooling phase measurements,the Rayleigh intensity behavior is normal.This hysteresis effect in the Rayleigh scattering is an indication that an intermediate range order exists in these glasses.The extent of the intermediate range order as determined from Rayleigh data compares well with values obtained obtained from Boson peak data.A model based on the modified Tool-Narayanaswamy concept is found to be in agreement with the calculations based on experimental results.

  13. Hyper-Rayleigh light-scattering spectra determined by ab initio collisional hyperpolarizabilities of He-Ne atomic pairs

    SciTech Connect

    Glaz, W.; Bancewicz, T.; Godet, J.-L.; Maroulis, G.; Haskopoulos, A.

    2006-04-15

    The collision-induced (CI) first hyperpolarizability tensor for the He-Ne pair composed of the lightest noble gas elements has been obtained on the grounds of an ab initio method as a function of the interatomic distance R. Collision-induced hyper-Rayleigh (CIHR) spectra scattered in mixtures of such atoms at temperatures of 95 and 295 K are computed in absolute units both quantum mechanically and classically for the frequency shifts up to 1000 cm{sup -1}. The spectral features of the CIHR profiles due to the vector b{sub 1} and septor b{sub 3} parts of the hyperpolarizability tensor are discussed. The quantum character of computed spectra, especially significant at lower temperatures, has been found out. The integrated intensities of the spectra have been evaluated and used as a criterion of the reliability of the computed profiles. The frequency-dependent depolarization ratio of the CIHR spectra was evaluated and discussed. The properties of the resulting HR profiles have been compared with the depolarized CI Rayleigh spectrum of the He-Ne pair.

  14. Multiple-Point Mass Flux Measurement System Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Clem, Michelle M.

    2009-01-01

    A multiple-point Rayleigh scattering diagnostic is being developed to provide mass flux measurements in gas flows. Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, temperature, and velocity measurements. Rayleigh scattered light from a focused 18 Watt continuous-wave laser beam is directly imaged through a solid Fabry-Perot etalon onto a CCD detector which permits spectral analysis of the light. The spatial resolution of the measurements is governed by the locations of interference fringes, which can be changed by altering the etalon characteristics. A prototype system has been used to acquire data in a Mach 0.56 flow to demonstrate feasibility of using this system to provide mass flux measurements. Estimates of measurement uncertainty and recommendations for system improvements are presented

  15. Progress on a Rayleigh Scattering Mass Flux Measurement Technique

    NASA Technical Reports Server (NTRS)

    Mielke-Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.; Hirt, Stefanie M.

    2010-01-01

    A Rayleigh scattering diagnostic has been developed to provide mass flux measurements in wind tunnel flows. Spectroscopic molecular Rayleigh scattering is an established flow diagnostic tool that has the ability to provide simultaneous density and velocity measurements in gaseous flows. Rayleigh scattered light from a focused 10 Watt continuous-wave laser beam is collected and fiber-optically transmitted to a solid Fabry-Perot etalon for spectral analysis. The circular interference pattern that contains the spectral information that is needed to determine the flow properties is imaged onto a CCD detector. Baseline measurements of density and velocity in the test section of the 15 cm x 15 cm Supersonic Wind Tunnel at NASA Glenn Research Center are presented as well as velocity measurements within a supersonic combustion ramjet engine isolator model installed in the tunnel test section.

  16. Rayleigh-Brillouin Scattering in Binary-Gas Mixtures

    NASA Astrophysics Data System (ADS)

    Gu, Z.; Ubachs, W.; Marques, W.; van de Water, W.

    2015-06-01

    Precise measurements are performed on spectral line shapes of spontaneous Rayleigh-Brillouin scattering in mixtures of the noble gases Ar and Kr, with He. Admixture of a light He atomic fraction results in marked changes of the spectra, although in all experiments He is merely a spectator atom: it affects the relaxation of density fluctuations of the heavy constituent, but its contribution to the scattered light intensity is negligibly small. The results are compared to a theory for the spectral line shape without adjustable parameters, yielding excellent agreement for the case of binary monatomic gases, signifying a step towards modeling and understanding of light scattering in more complex molecular media.

  17. Rayleigh scattering measurements of several fluorocarbon gases.

    PubMed

    Zadoo, Serena; Thompson, Jonathan E

    2011-11-01

    Integrating nephelometers are commonly used to monitor airborne particulate matter. However, they must be calibrated prior to use. The Rayleigh scattering coefficients (b(RS), Mm(-1)), scattering cross sections (σ(RS), cm(2)), and Rayleigh multipliers for tetrafluoromethane (R-14), sulfur hexafluoride, pentafluoroethane (HFC-125), hexafluoropropene (HFC-216), 1,1,1,2,3,3,3,-heptafluoropropane (HFC-227ea), and octafluorocyclobutane (C-318) are reported from measurements made using a Radiance Research M903 integrating nephelometer operating at λ = 530 nm and calibration with gases of known scattering constants. Rayleigh multipliers (±90% conf. int.) were found to be 2.6 ± 0.5, 6.60 ± 0.07, 7.5 ± 1, 14.8 ± 0.9, 15.6 ± 0.5, and 22.3 ± 0.8 times that of air, respectively. To the best of our knowledge, these are the first reported values for R-14, HFC-216, HFC-125, and C-318. Experimental accuracy is supported through measurements of values for SF(6) and HFC-227ea which agree to within 3% of previous literature reports. In addition to documenting fundamental Rayleigh scattering data for the first time, the information presented within will find use for calibration of optical scattering sensors such as integrating nephelometers. PMID:22027960

  18. Generalized Rayleigh scattering. II. Matrix source functions.

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.; Kasaurov, A. M.; Loskutov, V. M.; Viik, T.

    1995-11-01

    Numerical and analytical data are presented on the matrix source functions S(τ) of the standard problem of multiple generalized Rayleigh scattering (GRS) in homogeneous semi-infinite atmospheres with uniformly distributed embedded primary sources of partially polarized radiation. The source matrices S(τ) are found by the discrete-ordinate solution of the relevant 2x2 matrix transfer equation and by albedo shifting technique, which is a version of the accelerated {LAMBDA}-iteration approach. The dependence of the solution of the matrix transfer equation on the parameters of the problem of multiple molecular scattering, albedo of single scattering λ_I_ and depolarization factor W, is carefully considered. (The value W=1 corresponds to Rayleigh scattering, while for scalar isotropic scattering W=0). From the pair of the parameters (λ_I_, W) we switch to (λ_I_, λ_Q_), with λ_Q_=0.7Wλ_I_, and instead of the physically natural domain of the parameter values, λ_Iin[0,1], λ_ Qin[0,0.7λ_I_], in GRS we consider a wider one, λ_ I_, λ_Qin[0,1]. On the plane with the axes (λ_I_, λ_Q_), or the λ-plane, there is a one-parameter family of curves, the isopols, along which S(0) remains constant. The λ-plane and the isopols are the basic instruments in our analysis. Along with presenting the numerical data we discuss the asymptotic behavior of S(τ) for τ->{infinity}. It is shown that the matrix counterpart of the usual scalar conservative isotropic scattering is not the ordinary conservative Rayleigh scattering (λ_I_=1, λ_ Q_=0.7), but the biconservative scattering, i.e., scattering with λ_I_=λ_Q_=1. The analysis of the remarkable properties of biconservative scattering naturally leads to matrix generalizations of the Hopf-Bronstein relation, the Hopf constant etc.

  19. Hyper-Rayleigh scattering in centrosymmetric systems

    SciTech Connect

    Williams, Mathew D.; Ford, Jack S.; Andrews, David L.

    2015-09-28

    Hyper-Rayleigh scattering (HRS) is an incoherent mechanism for optical second harmonic generation. The frequency-doubled light that emerges from this mechanism is not emitted in a laser-like manner, in the forward direction; it is scattered in all directions. The underlying theory for this effect involves terms that are quadratic in the incident field and involves an even-order optical susceptibility (for a molecule, its associated hyperpolarizability). In consequence, HRS is often regarded as formally forbidden in centrosymmetric media. However, for the fundamental three-photon interaction, theory based on the standard electric dipole approximation, representable as E1{sup 3}, does not account for all experimental observations. The relevant results emerge upon extending the theory to include E1{sup 2}M1 and E1{sup 2}E2 contributions, incorporating one magnetic dipolar or electric quadrupolar interaction, respectively, to a consistent level of multipolar expansion. Both additional interactions require the deployment of higher orders in the multipole expansion, with the E1{sup 2}E2 interaction analogous in rank and parity to a four-wave susceptibility. To elicit the correct form of response from fluid or disordered media invites a tensor representation which does not oversimplify the molecular components, yet which can produce results to facilitate the interpretation of experimental observations. The detailed derivation in this work leads to results which are summarized for the following: perpendicular detection of polarization components both parallel and perpendicular to the pump radiation, leading to distinct polarization ratio results, as well as a reversal ratio for forward scattered circular polarizations. The results provide a route to handling data with direct physical interpretation, to enable the more sophisticated design of molecules with sought nonlinear optical properties.

  20. Hyper-Rayleigh scattering in centrosymmetric systems

    NASA Astrophysics Data System (ADS)

    Williams, Mathew D.; Ford, Jack S.; Andrews, David L.

    2015-09-01

    Hyper-Rayleigh scattering (HRS) is an incoherent mechanism for optical second harmonic generation. The frequency-doubled light that emerges from this mechanism is not emitted in a laser-like manner, in the forward direction; it is scattered in all directions. The underlying theory for this effect involves terms that are quadratic in the incident field and involves an even-order optical susceptibility (for a molecule, its associated hyperpolarizability). In consequence, HRS is often regarded as formally forbidden in centrosymmetric media. However, for the fundamental three-photon interaction, theory based on the standard electric dipole approximation, representable as E13, does not account for all experimental observations. The relevant results emerge upon extending the theory to include E12M1 and E12E2 contributions, incorporating one magnetic dipolar or electric quadrupolar interaction, respectively, to a consistent level of multipolar expansion. Both additional interactions require the deployment of higher orders in the multipole expansion, with the E12E2 interaction analogous in rank and parity to a four-wave susceptibility. To elicit the correct form of response from fluid or disordered media invites a tensor representation which does not oversimplify the molecular components, yet which can produce results to facilitate the interpretation of experimental observations. The detailed derivation in this work leads to results which are summarized for the following: perpendicular detection of polarization components both parallel and perpendicular to the pump radiation, leading to distinct polarization ratio results, as well as a reversal ratio for forward scattered circular polarizations. The results provide a route to handling data with direct physical interpretation, to enable the more sophisticated design of molecules with sought nonlinear optical properties.

  1. Simultaneous CARS and Interferometric Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Grinstead, Keith D., Jr.; Tedder, Sarah; Cutler, Andrew D.

    2006-01-01

    This paper reports for the first time the combination of a dual-pump coherent anti-Stokes Raman scattering system with an interferometric Rayleigh scattering system (CARS - IRS) to provide time-resolved simultaneous measurement of multiple properties in combustion flows. The system uses spectrally narrow green (seeded Nd:YAG at 532 nm) and yellow (552.9 nm) pump beams and a spectrally-broad red (607 nm) beam as the Stokes beam. A spectrometer and a planar Fabry-Perot interferometer used in the imaging mode are used to record the spectrally broad CARS spectra and the spontaneous Rayleigh scattering spectra, respectively. Time-resolved simultaneous measurement of temperature, absolute mole fractions of N2, O2, and H2, and two components of velocity in a Hencken burner flame were performed to demonstrate the technique.

  2. Time-Resolved Rayleigh Scattering Measurements in Hot Gas Flows

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen

    2008-01-01

    A molecular Rayleigh scattering technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded gas flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultipler tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. Mean and rms velocity and temperature fluctuation measurements in both an electrically-heated jet facility with a 10-mm diameter nozzle and also in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at NASA Glenn Research Center are presented.

  3. Rayleigh Scattering Measurements Using a Tunable Liquid Crystal Fabry-Perot Interferometer

    NASA Technical Reports Server (NTRS)

    Mielke-Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.

    2010-01-01

    Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, velocity, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of a tunable liquid crystal (LC) Fabry-Perot etalon in Rayleigh scattering experiments at NASA Glenn Research Center. The LC etalon provides a robust interferometry system that can be tuned rapidly by adjusting the voltage applied to the liquid crystal interface. Tuning the interferometer is often necessary to control the physical locations of the concentric interference fringes when Rayleigh light is imaged through the LC etalon. The LC etalon diagnostic system was tested in a 1-cm diameter nozzle flow in two different scattering configurations to evaluate its usefulness for Rayleigh measurements compared to a traditional non-tunable fused silica Fabry-Perot etalon.

  4. Generalized Rayleigh scattering. I. Basic theory.

    NASA Astrophysics Data System (ADS)

    Ivanov, V. V.

    1995-11-01

    The classsical problem of multiple molecular (in particular, Rayleigh) scattering in plane-parallel atmospheres is considered from a somewhat broader viewpoint than usual. The general approach and ideology are borrowed from non-LTE line formation theory. The main emphasis is on the depth dependence of the corresponding source matrix rather than on the emergent radiation. We study the azimuth-averaged radiation field of polarized radiation in a semi-infinite atmosphere with embedded primary sources. The corresponding 2x2 phase matrix of molecular scattering is P=(1-W) P_I_+W P_R_, where P_I_ and P_R_ are the phase matrices of the scalar isotropic scattering and of the Rayleigh scattering, respectively, and W is the depolarization parameter. Contrary to the usual assumption that W{in}[0,1], we assume W{in} [0,{infinity}) and call this generalized Rayleigh scattering (GRS). Using the factorization of P which is intimately related to its diadic expansion, we reduce the problem to an integral equation for the source matrix S(τ) with a matrix displacement kernel. In operator form this equation is S={LAMBDA}S+S^*^, where {LAMBDA} is the matrix {LAMBDA}-operator and S^*^ is the primary source term. This leads to a new concept, the matrix albedo of single scattering λ =diag(λ_I_,λ_Q_), where λ_I_ is the usual (scalar) single scattering albedo and λ_Q_=0.7Wλ_I_. Its use enables one to formulate matrix equivalents of many of the results of the scalar theory in exactly the same form as in the scalar case. Of crucial importance is the matrix equivalent of the sqrt(ɛ) law of the scalar theory. Another useful new concept is the λ-plane, i.e., the plane with the axes (λ_I_,λ_Q_). Systematic use of the matrix sqrt(ɛ) law and of the λ-plane proved to be a useful instrument in classifying various limiting and particular cases of GRS and in discussing numerical data on the matrix source functions (to be given in Paper II of the series).

  5. Rayleigh Scattering for Measuring Flow in a Nozzle Testing Facility

    NASA Technical Reports Server (NTRS)

    Gomez, Carlos R.; Panda, Jayanta

    2006-01-01

    A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-engine-component test facility for surveying supersonic plumes from jet-engine exhaust. A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-enginecomponent test facility for surveying supersonic plumes from jet-engine exhaust

  6. Ultraviolet Molecular Rayleigh Scattering Used to Measure Velocity in High-Speed Flow

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1997-01-01

    Molecular Rayleigh scattering offers a means to measure gas flow parameters including density, temperature, and velocity. No seeding of the flow is necessary. The Rayleigh scattered power is proportional to the gas density, the spectral width is related to the gas temperature, and the shift in the frequency of the spectral peak is proportional to one component of the fluid velocity. Velocity measurements based on Rayleigh scattering are more suitable for high-speed flow, where the bulk fluid velocity is on the order of, or larger than, the molecular thermal velocities. Use of ultraviolet wavelengths for Rayleigh scattering diagnostics is attractive for two reasons. First, the Rayleigh scattering cross section is proportional to the inverse 4th power of the wavelength. And second, the reflectivity of metallic surfaces is generally less than it is at longer wavelengths. This is of particular interest in confined flow situations, such as in small wind tunnels and aircraft engine components, where the stray laser light scattered from the windows and internal surfaces in the test facility limits the application of Rayleigh scattering diagnostics. In this work at the NASA Lewis Research Center, molecular Rayleigh scattering of the 266-nm fourth harmonic of a pulsed, injection seeded Nd:YAG (neodymium:yttriumaluminum- garnet) laser was used to measure velocity in a supersonic free air jet with a 9.3- mm exit diameter. The frequency of the Rayleigh scattered light was analyzed with a planar mirror Fabry-Perot interferometer used in a static imaging mode, with the images recorded on a cooled, high-quantum-efficiency charge-coupled discharge (CCD) camera. In addition, some unshifted light from the same laser pulse was imaged through the interferometer to generate a reference. Data were obtained with single laser pulses at velocities up to Mach 1.3. The measured velocities were in good agreement with velocities calculated from isentropic flow relations. Our conclusion from

  7. High-speed laser anemometry based on spectrally resolved Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1991-01-01

    Laser anemometry in unseeded flows based on the measurement of the spectrum of Rayleigh scattered laser light is reviewed. The use of molecular scattering avoids the well known problems (particle lag, biasing effects, seed generation, seed injection) of seeded flows. The fundamental limits on velocity measurement accuracy are determined using maximum likelihood methods. Measurement of the Rayleigh spectrum with scanning Fabry-Perot interferometers is analyzed and accuracy limits are established for both single pass and multipass configurations. Multipass configurations have much higher selectivity and are needed for measurements where there is a large amount of excess noise caused by stray laser light. It is shown that Rayleigh scattering is particularly useful for supersonic and hypersonic flows. The results of the analysis are compared with measurements obtained with a Rayleigh scattering diagnostic developed for study of the exhaust plume of a small hydrogen-oxygen rocket, where the velocities are in the range of 1000 to 5000 m/sec.

  8. Technical Report: Rayleigh Scattering Combustion Diagnostic

    SciTech Connect

    Adams, Wyatt; Hecht, Ethan

    2015-07-29

    A laser Rayleigh scattering (LRS) temperature diagnostic was developed over 8 weeks with the goal of studying oxy-combustion of pulverized coal char in high temperature reaction environments with high concentrations of carbon dioxide. Algorithms were developed to analyze data collected from the optical diagnostic system and convert the information to temperature measurements. When completed, the diagnostic will allow for the kinetic gasification rates of the oxy-combustion reaction to be obtained, which was previously not possible since the high concentrations of high temperature CO2 consumed thermocouples that were used to measure flame temperatures inside the flow reactor where the combustion and gasification reactions occur. These kinetic rates are important for studying oxycombustion processes suitable for application as sustainable energy solutions.

  9. 2D velocity and temperature measurements in high speed flows based on spectrally resolved Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1992-01-01

    The use of molecular Rayleigh scattering for measurements of gas velocity and temperature is evaluated. Molecular scattering avoids problems associated with the seeding required by conventional laser anemometry and particle image velocimetry. The technique considered herein is based on the measurement of the spectrum of the scattered light. Planar imaging of Rayleigh scattering using a laser light sheet is evaluated for conditions at 30 km altitude (typical hypersonic flow conditions). The Cramer-Rao lower bounds for velocity and temperature measurement uncertainties are calculated for an ideal optical spectrum analyzer and for a planar mirror Fabry-Perot interferometer used in a static, imaging mode. With this technique, a single image of the Rayleigh scattered light from clean flows can be analyzed to obtain temperature and one component of velocity. Experimental results are presented for planar velocity measurements in a Mach 1.3 air jet.

  10. Thomson Scattering Density Calibration by Rayleigh and Rotational Raman Scattering on NSTX

    SciTech Connect

    B.P. LeBlanc

    2008-07-16

    The multi-point Thomson scattering (MPTS) diagnostic measures the profiles of the electron temperature Te(R) and density ne(R) on the horizontal midplane of NSTX. Normal operation makes use of Rayleigh scattering in nitrogen or argon to derive the density profile. While the Rayleigh scattering ne(R) calibration has been validated by comparison with other density measurements and through its correlation with plasma phenomena, it does require dedicated detectors at the laser wavelength in this filter polychromator based diagnostic. The presence of dust and/or stray laser light precludes routine use of these dedicated spectral channels for Thomson scattering measurement. Hence it is of interest to investigate the use of Raman scattering in nitrogen for the purpose of density calibration, since it could free up detection equipment, which could then be used for the instrumentation of additional radial channels. In this paper the viewing optics "geometrical factor" profiles obtained from Rayleigh and Raman scattering are compared. While both techniques agree nominally, residual effects on the order of 10% remain and will be discussed.

  11. Gas temperature and density measurements based on spectrally resolved Rayleigh-Brillouin scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Lock, James A.

    1992-01-01

    The use of molecular Rayleigh scattering for measurements of gas density and temperature is evaluated. The technique used is based on the measurement of the spectrum of the scattered light, where both temperature and density are determined from the spectral shape. Planar imaging of Rayleigh scattering from air using a laser light sheet is evaluated for ambient conditions. The Cramer-Rao lower bounds for the shot-noise limited density and temperature measurement uncertainties are calculated for an ideal optical spectrum analyzer and for a planar mirror Fabry-Perot interferometer used in a static, imaging mode. With this technique, a single image of the Rayleigh scattered light can be analyzed to obtain density (or pressure) and temperature. Experimental results are presented for planar measurements taken in a heated air stream.

  12. Rayleigh scattering: blue sky thinking for future CMB observations

    SciTech Connect

    Lewis, Antony

    2013-08-01

    Rayleigh scattering from neutral hydrogen during and shortly after recombination causes the CMB anisotropies to be significantly frequency dependent at high frequencies. This may be detectable with Planck, and would be a strong signal in any future space-based CMB missions. The later peak of the Rayleigh visibility compared to Thomson scattering gives an increased large-scale CMB polarization signal that is a greater than 4% effect for observed frequencies ν ∼> 500GHz. There is a similar magnitude suppression on small scales from additional damping. Due to strong correlation between the Rayleigh and primary signal, measurement of the Rayleigh component is limited by noise and foregrounds, not cosmic variance of the primary CMB, and should observable over a wide range of angular scales at frequencies 200GHz ∼< ν ∼< 800GHz. I give new numerical calculations of the temperature and polarization power spectra, and show that future CMB missions could measure the temperature Rayleigh cross-spectrum at high precision, detect the polarization from Rayleigh scattering, and also accurately determine the cross-spectra between the Rayleigh temperature signal and primary polarization. The Rayleigh scattering signal may provide a powerful consistency check on recombination physics. In principle it can be used to measure additional horizon-scale primordial perturbation modes at recombination, and distinguish a significant tensor mode B-polarization signal from gravitational lensing at the power spectrum level.

  13. Study of Injection of Helium into Supersonic Air Flow Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seaholtz, Richard G.; Buggele, Alvin E.

    1997-01-01

    A study of the transverse injection of helium into a Mach 3 crossflow is presented. Filtered Rayleigh scattering is used to measure penetration and helium mole fraction in the mixing region. The method is based on planar molecular Rayleigh scattering using an injection-seeded, frequency-doubled ND:YAG pulsed laser and a cooled CCD camera. The scattered light is filtered with an iodine absorption cell to suppress stray laser light. Preliminary data are presented for helium mole fraction and penetration. Flow visualization images obtained with a shadowgraph and wall static pressure data in the vicinity of the injection are also presented.

  14. Rayleigh scattering and depolarization ratio in linear alkylbenzene

    NASA Astrophysics Data System (ADS)

    Liu, Qian; Zhou, Xiang; Huang, Wenqian; Zhang, Yuning; Wu, Wenjie; Luo, Wentai; Yu, Miao; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-09-01

    It is planned to use linear alkylbenzene (LAB) as the organic solvent for the Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors, due to its ultra-transparency. However, the current Rayleigh scattering length calculation for LAB disagrees with the experimental measurement. This paper reports for the first time that the Rayleigh scattering of LAB is anisotropic, with a depolarization ratio of 0.31±0.01(stat.)±0.01(sys.). We use an indirect method for Rayleigh scattering measurement with the Einstein-Smoluchowski-Cabannes formula, and the Rayleigh scattering length of LAB is determined to be 28.2±1.0 m at 430 nm.

  15. Rayleigh scattering in the atmospheres of hot stars

    NASA Astrophysics Data System (ADS)

    Fišák, J.; Krtička, J.; Munzar, D.; Kubát, J.

    2016-05-01

    Context. Rayleigh scattering is a result of an interaction of photons with bound electrons. Rayleigh scattering is mostly neglected in calculations of hot star model atmospheres because most of the hydrogen atoms are ionized and the heavier elements have a lower abundance than hydrogen. In atmospheres of some chemically peculiar stars, helium overabundant regions containing singly ionized helium are present and Rayleigh scattering can be a significant opacity source. Aims: We evaluate the contribution of Rayleigh scattering by neutral hydrogen and singly ionized helium in the atmospheres of hot stars with solar composition and in the atmospheres of helium overabundant stars. Methods: We computed several series of model atmospheres using the TLUSTY code and emergent fluxes using the SYNSPEC code. These models describe atmospheres of main sequence B-type stars with different helium abundance. We used an existing grid of models for atmospheres with solar chemical composition and we calculated an additional grid for helium-rich stars with N(He)/N(H) = 10. Results: Rayleigh scattering by neutral hydrogen can be neglected in atmospheres of hot stars, while Rayleigh scattering by singly ionized helium can be a non-negligible opacity source in some hot stars, especially in helium-rich stars.

  16. Correction of Rayleigh Scattering Effects in Cloud Optical Thickness Retrievals

    NASA Technical Reports Server (NTRS)

    Wang, Meng-Hua; King, Michael D.

    1997-01-01

    We present results that demonstrate the effects of Rayleigh scattering on the 9 retrieval of cloud optical thickness at a visible wavelength (0.66 Am). The sensor-measured radiance at a visible wavelength (0.66 Am) is usually used to infer remotely the cloud optical thickness from aircraft or satellite instruments. For example, we find that without removing Rayleigh scattering effects, errors in the retrieved cloud optical thickness for a thin water cloud layer (T = 2.0) range from 15 to 60%, depending on solar zenith angle and viewing geometry. For an optically thick cloud (T = 10), on the other hand, errors can range from 10 to 60% for large solar zenith angles (0-60 deg) because of enhanced Rayleigh scattering. It is therefore particularly important to correct for Rayleigh scattering contributions to the reflected signal from a cloud layer both (1) for the case of thin clouds and (2) for large solar zenith angles and all clouds. On the basis of the single scattering approximation, we propose an iterative method for effectively removing Rayleigh scattering contributions from the measured radiance signal in cloud optical thickness retrievals. The proposed correction algorithm works very well and can easily be incorporated into any cloud retrieval algorithm. The Rayleigh correction method is applicable to cloud at any pressure, providing that the cloud top pressure is known to within +/- 100 bPa. With the Rayleigh correction the errors in retrieved cloud optical thickness are usually reduced to within 3%. In cases of both thin cloud layers and thick ,clouds with large solar zenith angles, the errors are usually reduced by a factor of about 2 to over 10. The Rayleigh correction algorithm has been tested with simulations for realistic cloud optical and microphysical properties with different solar and viewing geometries. We apply the Rayleigh correction algorithm to the cloud optical thickness retrievals from experimental data obtained during the Atlantic

  17. Brillouin amplification and processing of the Rayleigh scattered signal.

    PubMed

    Mermelstein, David; Shacham, Eliashiv; Biton, Moran; Sternklar, Shmuel

    2015-07-15

    Brillouin amplification of Rayleigh scattering is demonstrated using two different configurations. In the first technique, the Rayleigh scattering and amplification occurs simultaneously in the same fiber. In the second technique, the amplification takes place in a second fiber. The differences between the two techniques are delineated. Using the second technique, we demonstrate single-sideband off-resonant Brillouin amplification of the Rayleigh signal. This technique is shown to enhance the SNR of a signal that is due to vibration-induced strain on the fiber. PMID:26176464

  18. Effects of Rayleigh scattering on the CMB and cosmic structure

    NASA Astrophysics Data System (ADS)

    Alipour, Elham; Sigurdson, Kris; Hirata, Christopher M.

    2015-04-01

    During and after recombination, in addition to Thomson scattering with free electrons, photons also couple to neutral hydrogen and helium atoms through Rayleigh scattering. This coupling influences both cosmic microwave background (CMB) anisotropies and the distribution of matter in the Universe. The frequency dependence of the Rayleigh cross section breaks the thermal nature of CMB temperature and polarization anisotropies and effectively doubles the number of variables needed to describe CMB intensity and polarization statistics, while the additional atomic coupling changes the matter distribution and the lensing of the CMB. We introduce a new method to capture the effects of Rayleigh scattering on cosmological power spectra. Rayleigh scattering modifies CMB temperature and polarization anisotropies at the ˜1 % level at 35 GHz (scaling ∝ν4 ), and modifies matter correlations by as much as ˜0.3 %. We show the Rayleigh signal, especially the cross-spectra between the thermal (Rayleigh) E -polarization and Rayleigh (thermal) intensity signal, may be detectable with future CMB missions even in the presence of foregrounds, and how this new information might help to better constrain the cosmological parameters.

  19. Instantaneous flow measurements in a supersonic wind tunnel using spectrally resolved Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Buggele, Alvin E.; Reeder, Mark F.

    1995-01-01

    Results of a feasibility study to apply laser Rayleigh scattering to non-intrusively measure flow properties in a small supersonic wind tunnel are presented. The technique uses an injection seeded, frequency doubled Nd:YAG laser tuned to an absorption band of iodine. The molecular Rayleigh scattered light is filtered with an iodine cell to block light at the laser frequency. The Doppler-shifted Rayleigh scattered light that passes through the iodine cell is analyzed with a planar mirror Fabry-Perot interferometer used in a static imaging mode. An intensified CCD camera is used to record the images. The images are analyzed at several subregions, where the flow velocity is determined. Each image is obtained with a single laser pulse, giving instantaneous measurements.

  20. Rayleigh Scattering Diagnostic for Measurement of Temperature and Velocity in Harsh Environments

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Greer, Lawrence C., III

    1998-01-01

    A molecular Rayleigh scattering system for temperature and velocity measurements in unseeded flows is described. The system is capable of making measurements in the harsh environments commonly found in aerospace test facilities, which may have high acoustic sound levels, varying temperatures, and high vibration levels. Light from an argon-ion laser is transmitted via an optical fiber to a remote location where two flow experiments were located. One was a subsonic free air jet; the second was a low-speed heated airjet. Rayleigh scattered light from the probe volume was transmitted through another optical fiber from the remote location to a controlled environment where a Fabry-Perot interferometer and cooled CCD camera were used to analyze the Rayleigh scattered light. Good agreement between the measured velocity and the velocity calculated from isentropic flow relations was demonstrated (less than 5 m/sec). The temperature measurements, however, exhibited systematic errors on the order of 10-15%.

  1. Jet Evolution Visualized and Quantified Using Filtered Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Reeder, Mark F.

    1996-01-01

    Filtered Rayleigh scattering was utilized as a flow diagnostic in an investigation of a method for enhancing mixing in supersonic jets. The primary objectives of the study were to visualize the effect of vortex generating tabs on supersonic jets, to exact quantitative data from these planar visualizations, and to detect the presence of secondary flows (i.e., streamwise vorticity) generated by the tabs. An injection seeded frequency-doubled Nd:YAG was the light source and a 14 bit Princeton Instruments iodine charge coupled display (ICCD) camera recorded the image through an iodine cell. The incident wave length of the laser was held constant for each flow case so that the filter absorbed unwanted background light, but permitted part of the thermally broadened Rayleigh scattering light to pas through. The visualizations were performed for axisymmetric jets (D=1.9 cm) operated at perfectly expanded conditions for Mach 1.0, 1.5, and 2.0. All data were recorded for the jet cross section at x/D=3. One hundred instantaneous images were recorded and averaged for each case, with a threshold set to eliminate unavoidable particulate scattering. A key factor in these experiments was that the stagnation air was heated such that the expansion of the flow in the nozzle resulted in the static temperature in the jet being equal to the ambient temperature, assuming isentropic flow. Since the thermodynamic conditions of the flow were approximately the same for each case, increases in the intensity recorded by the ICCD camera could be directly attributed to the Doppler shift, and hence velocity. Visualizations were performed for Mach 1.5 and Mach 2.0 jets with tabs inserted at the nozzle exit. The distortion of the jet was readily apparent and was consistent with Mie scattering-based visualizations. Asymmetry in the intensities of the images indicate the presence of secondary flow patterns which are consistent with the streamwise vortices measured using more traditional diagnostics

  2. Rayleigh scattering of a Gaussian laser beam from expanding clusters

    SciTech Connect

    Kumar, Manoj; Tripathi, V. K.

    2009-12-15

    Rayleigh scattering of an intense laser with Gaussian temporal and radial profiles from clustered gases is examined. The laser quickly converts the clusters into plasma balls with electron cloud of each ball executing large excursions about the ion sphere. The laser also heats the electrons. As the clusters expand under hydrodynamic pressure, plasma frequency of the cluster electrons omega{sub pe} decreases. The temporal rate of decrease in omega{sub pe} is maximum on laser axis and falls off with r. As the electron density of a cluster approaches plasma resonance, omega{sub pe}=omegasq root(3) (where omega is the frequency of the laser) the oscillatory electron cloud of the cluster produces resonantly enhanced Rayleigh scattering. This resonant enhancement first occurs in clusters on laser axis and afterward in farther clusters. The diffraction divergence of the laser limits the length of the cluster plasma, hence the Rayleigh scattering.

  3. Control of experimental uncertainties in filtered Rayleigh scattering measurements

    NASA Technical Reports Server (NTRS)

    Forkey, Joseph N.; Finkelstein, N. D.; Lempert, Walter R.; Miles, Richard B.

    1995-01-01

    Filtered Rayleigh Scattering is a technique which allows for measurement of velocity, temperature, and pressure in unseeded flows, spatially resolved in 2-dimensions. We present an overview of the major components of a Filtered Rayleigh Scattering system. In particular, we develop and discuss a detailed theoretical model along with associated model parameters and related uncertainties. Based on this model, we then present experimental results for ambient room air and for a Mach 2 free jet, including spatially resolved measurements of velocity, temperature, and pressure.

  4. Nd:YAG Laser-Based Dual-Line Detection Rayleigh Scattering and Current Efforts on UV, Filtered Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Otugen, M. Volkan; Popovic, Svetozar

    1996-01-01

    Ongoing research in Rayleigh scattering diagnostics for variable density low speed flow applications and for supersonic flow measurements are described. During the past several years, the focus has been on the development and use of a Nd:YAG-based Rayleigh scattering system with improved signal-to-noise characteristics and with applicability to complex, confined flows. This activity serves other research projects in the Aerodynamics Laboratory which require the non-contact, accurate, time-frozen measurement of gas density, pressure, and temperature (each separately), in a fairly wide dynamic range of each parameter. Recently, with the acquisition of a new seed-injected Nd:YAG laser, effort also has been directed to the development of a high-speed velocity probe based on a spectrally resolved Rayleigh scattering technique.

  5. Horizontal lidar measurements for the proof of spontaneous Rayleigh-Brillouin scattering in the atmosphere.

    PubMed

    Witschas, Benjamin; Lemmerz, Christian; Reitebuch, Oliver

    2012-09-01

    Several atmospheric lidar techniques rely on the exact knowledge of the spectral line shape of molecular scattered light in air, which, however, has not been accurately measured in real atmosphere up to now. In this paper we report on the investigation of spontaneous Rayleigh-Brillouin scattering within the atmosphere, utilizing horizontal lidar measurements (λ=355 nm, θ=180°) performed from the mountain observatory Schneefernerhaus (2650 m), located below Germany's highest mountain, the Zugspitze. These lidar measurements give proof of the effect of Brillouin scattering within the atmosphere for the first time to our knowledge. The measurements confirm that the Tenti S6 model can be used to adequately describe spontaneous Rayleigh-Brillouin spectra of light scattered in air under real atmospheric conditions. The presented results are of relevance for spectrally resolving lidars like those deployed on the Atmospheric Dynamics Mission Aeolus (ADM-Aeolus) andthe Earth Clouds, Aerosols, and Radiation Explorer Mission (EarthCARE). PMID:22945169

  6. Flow Visualization of Density in a Cryogenic Wind Tunnel Using Planar Rayleigh and Raman Scattering

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.; Shirinzadeh, Behrooz

    2002-01-01

    Using a pulsed Nd:YAG laser (532 nm) and a gated, intensified charge-coupled device, planar Rayleigh and Raman scattering techniques have been used to visualize the unseeded Mach 0.2 flow density in a 0.3-meter transonic cryogenic wind tunnel. Detection limits are determined for density measurements by using both unseeded Rayleigh and Raman (N2 vibrational) methods. Seeding with CO2 improved the Rayleigh flow visualization at temperatures below 150 K. The seeded Rayleigh version was used to demonstrate the observation of transient flow features in a separated boundary layer region, which was excited with an oscillatory jet. Finally, a significant degradation of the laser light sheet, in this cryogenic facility, is discussed.

  7. Investigation of laser temporal pulse duration on Rayleigh scattering

    SciTech Connect

    Nee, T.A.; Roberts, J.R.

    1982-02-01

    Relative Rayleigh-scattering cross sections from nitrogen have been measured for various pulse durations and wavelengths of incident laser radiation. No pulse-duration dependence has been observed for laser pulses as short as 5 ns, and classical theory is found to be still valid over the pulse-width range (5< or =..delta..t< or =110 ns) of our observations.

  8. Hyper-Rayleigh scattering of gold nanorods and their relationship with linear assemblies of gold nanospheres.

    PubMed

    Nappa, Jérôme; Revillod, Guillaume; Abid, Jean-Pierre; Russier-Antoine, Isabelle; Jonin, Christian; Benichou, Emmanuel; Girault, Hubert H; Brevet, Pierre F

    2004-01-01

    The surface plasmon enhanced hyper-Rayleigh scattering light collected from an aqueous solution of gold nanorods is reported. A non negligible part of the signal is attributed to a photoluminescence background attributed to the electron hole recombination following multiphoton excitation of d-valence band electrons into the sp-conduction band. This radiative relaxation process is likely favored by the presence of the organic species adsorbed at the surface of the nanorods. The absolute value for the hyperpolarisability of nanorods is also compared by the external reference method to that of para-nitroaniline and found to be rather large although an absolute value cannot be given because the exact number density of the gold nanorods is unaccessible. This value is however compared with values reported for linear assemblies of gold spherical nanoparticles and further support the simple model of gold metal ellipsoids to describe the hyper-Rayleigh light intensities. The polarisation analysis of the hyper-Rayleigh scattering light is also determined for gold nanorods and compared to the expected one for gold nanospheres. For the latter spheres, the weakness of the signal intensities precludes a definite comparison with the model. On the opposite, for the nanorods, the polarisation dependence of the hyper-Rayleigh scattered light clearly deviates from the one expected for nanospheres. PMID:14750669

  9. Estimating the probability density of the scattering cross section from Rayleigh scattering experiments

    NASA Astrophysics Data System (ADS)

    Hengartner, Nicolas; Talbot, Lawrence; Shepherd, Ian; Bickel, Peter

    1995-06-01

    An important parameter in the experimental study of dynamics of combustion is the probability distribution of the effective Rayleigh scattering cross section. This cross section cannot be observed directly. Instead, pairs of measurements of laser intensities and Rayleigh scattering counts are observed. Our aim is to provide estimators for the probability density function of the scattering cross section from such measurements. The probability distribution is derived first for the number of recorded photons in the Rayleigh scattering experiment. In this approach the laser intensity measurements are treated as known covariates. This departs from the usual practice of normalizing the Rayleigh scattering counts by the laser intensities. For distributions supported on finite intervals two one based on expansion of the density in

  10. High-speed laser anemometry based on spectrally resolved Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.

    1991-01-01

    Laser anemometry in unseeded flows based on the measurement of the spectrum of Rayleigh scattered laser light is reviewed. The use of molecular scattering avoids the well-known problems (particle lag, biasing effects, seed generation, seed injection) of seeded flows. The fundamental limits on velocity measurement accuracy are determined using maximum likelihood methods. Measurement of the Rayleigh spectrum with scanning Fabry-Perot interferometers is analyzed and accuracy limits are established for both single pass and multi-pass configurations. Multi-pass configurations have much higher selectivity and are needed for measurements where there is a large amount of excess noise caused by stray laser light. It is shown that Rayleigh scattering is particularly useful for supersonic and hypersonic flows. The results of the analysis are compared with measurements obtained with a Rayleigh scattering diagnostic developed for study of the exhaust plume of a small hydrogen-oxygen rocket, where the velocities are in the range 1000 to 5000 m/sec.

  11. Rayleigh scattering of a spherical sound wave.

    PubMed

    Godin, Oleg A

    2013-02-01

    Acoustic Green's functions for a homogeneous medium with an embedded spherical obstacle arise in analyses of scattering by objects on or near an interface, radiation by finite sources, sound attenuation in and scattering from clouds of suspended particles, etc. An exact solution of the problem of diffraction of a monochromatic spherical sound wave on a sphere is given by an infinite series involving products of Bessel functions and Legendre polynomials. In this paper, a simple, closed-form solution is obtained for scattering by a sphere with a radius that is small compared to the wavelength. Soft, hard, impedance, and fluid obstacles are considered. The solution is valid for arbitrary positions of the source and receiver relative to the scatterer. Low-frequency scattering is shown to be rather sensitive to boundary conditions on the surface of the obstacle. Low-frequency asymptotics of the scattered acoustic field are extended to transient incident waves. The asymptotic expansions admit an intuitive interpretation in terms of image sources and reduce to classical results in appropriate limiting cases. PMID:23363090

  12. Study of Fabry-Perot Etalon Stability and Tuning for Spectroscopic Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Clem, Michelle M.; Mielke-Fagan, Amy F.; Elam, Kristie A.

    2010-01-01

    The Fabry-Perot interferometer is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating flow properties such as gas velocity and temperature. Rayleigh scattered light from a focused laser beam can be directly imaged through a solid Fabry-Perot etalon onto a CCD detector to provide the spectral content of the scattered light. The spatial resolution of the measurements is governed by the locations of interference fringes. The location of the fringes can be changed by altering the etalon?s physical characteristics, such as thickness and index of refraction. For a fused silica solid etalon the physical properties can be adjusted by changing the etalon temperature; hence changing the order of the interference pattern and the physical fringe locations. Controlling the temperature of the etalon can provide for a slow time-response spatial scanning method for this type of etalon system. A custom designed liquid crystal Fabry-Perot (LCFP) can provide for a fast time-response method of scanning the etalon system. Voltage applied to the liquid crystal interface sets the etalon?s properties allowing Rayleigh measurements to be acquired at varying spatial locations across the image of the laser beam over a very short time period. A standard fused silica etalon and a tunable LCFP etalon are characterized to select the system that is best suited for Rayleigh scattering measurements in subsonic and supersonic flow regimes. A frequency-stabilized laser is used to investigate the apparent frequency stability and temperature sensitivity of the etalon systems. Frequency stability and temperature sensitivity data of the fused silica and LCFP etalon systems are presented in this paper, along with measurements of the LCFP etalon?s tuning capabilities. Rayleigh scattering velocity measurements with both etalon systems are presented, in an effort to determine which etalon is better suited to provide optical flow

  13. Rayleigh scattering for density measurements in premixed flames

    NASA Astrophysics Data System (ADS)

    Gouldin, F. C.; Halthore, R. N.

    1986-09-01

    Rayleigh scattering measurements for molecular number density in turbulent, premixed CH4-air flames are discussed, and data for both flamelet passage time distributions and power spectral density functions are reported and compared to the recent predictions of Bray, Libby and Moss (1984). Measurement problems associated with variations in mixture-averaged Rayleigh scattering cross section, index of refraction fluctuations, finite spatial and temporal resolution and with scattering from particles are discussed. It is concluded that these effects are relatively minor in the reported experiments. Correction procedures are suggested for the effects of cross section variation and of finite resolution. Passage time and spectral data support the Bray, Libby and Moss hypothesis for the passage time distribution function. Furthermore, model predictions for the variation across the flame brush of mean passage times for both reactant and product eddies are in reasonable agreement with experiment. Finally, the data suggest that these mean times scale in part with Ū and λ in the reactant flow.

  14. Errors induced by the neglect of polarization in radiance calculations for Rayleigh-scattering atmospheres

    NASA Technical Reports Server (NTRS)

    Mishchenko, M. I.; Lacis, A. A.; Travis, L. D.

    1994-01-01

    Although neglecting polarization and replacing the rigorous vector radiative transfer equation by its approximate scalar counterpart has no physical background, it is a widely used simplification when the incident light is unpolarized and only the intensity of the reflected light is to be computed. We employ accurate vector and scalar multiple-scattering calculations to perform a systematic study of the errors induced by the neglect of polarization in radiance calculations for a homogeneous, plane-parallel Rayleigh-scattering atmosphere (with and without depolarization) above a Lambertian surface. Specifically, we calculate percent errors in the reflected intensity for various directions of light incidence and reflection, optical thicknesses of the atmosphere, single-scattering albedos, depolarization factors, and surface albedos. The numerical data displayed can be used to decide whether or not the scalar approximation may be employed depending on the parameters of the problem. We show that the errors decrease with increasing depolarization factor and/or increasing surface albedo. For conservative or nearly conservative scattering and small surface albedos, the errors are maximum at optical thicknesses of about 1. The calculated errors may be too large for some practical applications, and, therefore, rigorous vector calculations should be employed whenever possible. However, if approximate scalar calculations are used, we recommend to avoid geometries involving phase angles equal or close to 0 deg and 90 deg, where the errors are especially significant. We propose a theoretical explanation of the large vector/scalar differences in the case of Rayleigh scattering. According to this explanation, the differences are caused by the particular structure of the Rayleigh scattering matrix and come from lower-order (except first-order) light scattering paths involving right scattering angles and right-angle rotations of the scattering plane.

  15. Cavity-modified collective Rayleigh scattering of two atoms.

    PubMed

    Reimann, René; Alt, Wolfgang; Kampschulte, Tobias; Macha, Tobias; Ratschbacher, Lothar; Thau, Natalie; Yoon, Seokchan; Meschede, Dieter

    2015-01-16

    We report on the observation of cooperative radiation of exactly two neutral atoms strongly coupled to the single mode field of an optical cavity, which is close to the lossless-cavity limit. Monitoring the cavity output power, we observe constructive and destructive interference of collective Rayleigh scattering for certain relative distances between the two atoms. Because of cavity backaction onto the atoms, the cavity output power for the constructive two-atom case (N=2) is almost equal to the single-emitter case (N=1), which is in contrast to free-space where one would expect an N^{2} scaling of the power. These effects are quantitatively explained by a classical model as well as by a quantum mechanical model based on Dicke states. We extract information on the relative phases of the light fields at the atom positions and employ advanced cooling to reduce the jump rate between the constructive and destructive atom configurations. Thereby we improve the control over the system to a level where the implementation of two-atom entanglement schemes involving optical cavities becomes realistic. PMID:25635545

  16. Dual-Line Detection Rayleigh Scattering Measurements of Density and Temperature

    NASA Technical Reports Server (NTRS)

    Annen, Kurt; Otugen, Volkan; Seasholtz, Richard

    1996-01-01

    Measurements of the laser Rayleigh scattering signal in a flow to determine density and temperature have been commonly employed in open flames and in wind tunnel environments. In these measurements, the density or reciprocal temperature is correlated with the Rayleigh scattering signal intensity. A major advantage of Rayleigh scattering for these applications is the simple experimental arrangement allowed by this technique. Intensity-based Rayleigh scattering measurements of density and temperature have been limited to relatively clean flows in open environments so that interference from particle scattering and laser scattering is minimal. A new approach, using dual-line detection Rayleigh (DLDR) scattering extends the applicability of Rayleigh scattering measurements of density and temperature to enclosed environments where surface scattering interference is high. Depending on particle size and optical properties, this approach may also reduce interference from particle scattering.

  17. Suppression of Rayleigh-scattering-induced noise in OEOs.

    PubMed

    Okusaga, Olukayode; Cahill, James P; Docherty, Andrew; Menyuk, Curtis R; Zhou, Weimin; Carter, Gary M

    2013-09-23

    Optoelectronic oscillators (OEOs) are hybrid RF-photonic devices that promise to be environmentally robust high-frequency RF sources with very low phase noise. Previously, we showed that Rayleigh-scattering-induced noise in optical fibers coupled with amplitude-to-phase noise conversion in photodetectors and amplifiers leads to fiber-length-dependent noise in OEOs. In this work, we report on two methods for the suppression of this fiber-length-dependent noise: altering the amplitude-dependent phase delay of the OEO loops and suppressing the Rayleigh-scattering-induced noise in optical fibers. We report a 20 dB reduction in the flicker phase noise of a 6 km OEO via these suppression techniques. PMID:24104117

  18. Rayleigh scattering and nonlinear inversion of elastic waves

    SciTech Connect

    Gritto, R.

    1995-12-01

    Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of {minus}100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k{sub p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.

  19. Scattered Light And Fluorescent Photomechanics

    NASA Astrophysics Data System (ADS)

    Fourney, M. E.; Chang, Ban W.

    1987-02-01

    A new technique for determining the stress state in a three-dimensional transparent body is described. This method involves cast-ing dye molecules into a model material and using the fluorescent light to analysis the stress state. The techniques of scattered light photoelasticity and speckle interferometry are considered and the enhancement of these techniques by the use of fluorescent is reported. The amount of illumination is greatly increased and the wavelength red-shifted, which eliminates the undesirable boundary halo; however, at the expense of a loss of coherence and a degree of depolarization of the light. Rhodamine 6G dye molecules are cast into gelatin, epoxy resin (PLM-4) and urethane rubber (Solithane 113) model materials. The light scattering, fluorescent, and fringe formation processes of each material is investigated. It is observed that even for the standard scattered light photoelastic materials without dye molecules the scattering is not Rayleigh, but rather has a large amount of wavelength broadening, the center wavelength, is red-shifted, and a high degree of depolarization occurs. A theory of photoelastic fringe formation for fluorescent materials is proposed. Experimental results are presented and the use of digital image processor in filtering background illumination is shown to greatly enhance fringe visibility.

  20. On the critical role of Rayleigh scattering in single-molecule surface-enhanced Raman scattering via a plasmonic nanogap.

    PubMed

    Chen, Bao-Qin; Zhang, Chao; Li, Jiafang; Li, Zhi-Yuan; Xia, Younan

    2016-08-25

    Electromagnetic and chemical enhancement mechanisms are commonly used to account for single-molecule surface-enhanced Raman scattering (SM-SERS). Due to many practical limitations, however, the overall enhancement factor summed up from these two mechanisms is typically 5-6 orders of magnitude below the level of 10(14)-10(15) required for SM-SERS. Here, we demonstrate that the multiple elastic Rayleigh scattering of a molecule could play a critical role in further enhancing the Raman signal, when the molecule is trapped in a 2 nm gap between two Ag nanoparticles, pushing the overall enhancement factor close to the level needed for SM-SERS. As a universal physical process for all molecules interacting with light, we believe that Rayleigh scattering plays a pivotal and as yet unrecognized role in SERS, in particular, for enabling single-molecule sensitivity. PMID:27526632

  1. Rayleigh Scattering Diagnostic for Simultaneous Measurements of Dynamic Density and Velocity

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, J.

    2000-01-01

    A flow diagnostic technique based on the molecular Rayleigh scattering of laser light is used to obtain dynamic density and velocity data in turbulent flows. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer and recording information about the interference pattern with a multiple anode photomultiplier tube (PMT). An artificial neural network is used to process the signals from the PMT to recover the velocity time history, which is then used to calculate the velocity power spectrum. The technique is illustrated using simulated data. The results of an experiment to measure the velocity power spectrum in a low speed (100 rn/sec) flow are also presented.

  2. Rayleigh Scattering Diagnostic for Dynamic Measurement of Velocity Fluctuations in High Speed Jets

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, Jayanta; Elam, Kristie A.

    2001-01-01

    A flow diagnostic technique based on the molecular Rayleigh scattering of laser light is used to obtain dynamic density and velocity data in a high speed flow. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer used in the static, imaging mode. An analysis is presented that established a lower bound for measurement uncertainty of about 20 m/sec for individual velocity measurements obtained in a 100 microsecond time interval. Software and hardware interfaces were developed to allow computer control of all aspects of the experiment and data acquisition. The signals from three photomultiplier tubes were simultaneously recorded using photon counting at a 10 kHz sampling rate and 10 second recording periods. Density and velocity data, including distribution functions and power spectra, taken in a Mach 0.8 free jet, are presented.

  3. Apparatus and Method for Measuring Strain in Optical Fibers using Rayleigh Scatter

    NASA Technical Reports Server (NTRS)

    Froggatt, Mark E. (Inventor); Moore, Jason P. (Inventor)

    2003-01-01

    An apparatus and method for measuring strain in an optical fiber using the spectral shift of Rayleigh scattered light. The interference pattern produced by an air gap reflector and backscattered radiation is measured. Using Fourier Transforms, the spectrum of any section of fiber can be extracted. Cross correlation with an unstrained measurement produces a correlation peak. The location of the correlation peak indicates the strain level in the selected portion of optical fiber.

  4. Rocket plume flowfield characterization using laser Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Zupanc, Frank J.; Weiss, Jonathan M.

    1992-01-01

    A Doppler-resolved laser Rayleigh scattering diagnostic was applied to a 111 N thrust, regenerative and fuel-film cooled, gaseous hydrogen/gaseous oxygen rocket engine. The axial and radial mean gas velocities were measured from the net Doppler shifts observed for two different scattering angles. Translational temperatures and number densities were estimated from the Doppler widths and scattered intensities, respectively, by assuming that water was the dominant scattering species in the exhaust. The experimental results are compared with theoretical predictions from a full Navier-Stokes code (RD/RPLUS) and the JANNAF Two-Dimensional Kinetics (TDK) and Standardized Plume Flowfield (SPF-II) codes. Discrepancies between the measured and predicted axial velocities, temperatures, and number densities are evident. Radial velocity measurements, however, show excellent agreement with predictions. The discrepancies are attributed primarily to inefficient mixing and combustion caused by the injection of excessive oxidizer along one side of the thrust chamber. Thrust and mass flow rate estimates obtained from the Rayleigh measurements show excellent agreement with the globally measured values.

  5. Setting up a Rayleigh Scattering Based Flow Measuring System in a Large Nozzle Testing Facility

    NASA Technical Reports Server (NTRS)

    Panda, Jayanta; Gomez, Carlos R.

    2002-01-01

    A molecular Rayleigh scattering based air density measurement system has been built in a large nozzle testing facility at NASA Glenn Research Center. The technique depends on the light scattering by gas molecules present in air; no artificial seeding is required. Light from a single mode, continuous wave laser was transmitted to the nozzle facility by optical fiber, and light scattered by gas molecules, at various points along the laser beam, is collected and measured by photon-counting electronics. By placing the laser beam and collection optics on synchronized traversing units, the point measurement technique is made effective for surveying density variation over a cross-section of the nozzle plume. Various difficulties associated with dust particles, stray light, high noise level and vibration are discussed. Finally, a limited amount of data from an underexpanded jet are presented and compared with expected variations to validate the technique.

  6. Rayleigh Scattering Diagnostic for Measurement of Velocity and Density Fluctuation Spectra

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, Jayanta; Elam, Kristie A.

    2002-01-01

    A new molecular Rayleigh scattering based flow diagnostic is used for the first time to measure the power spectrum of gas density and radial velocity component in the plumes of high speed jets. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer used in the static, imaging mode. The PC based data acquisition system is capable of simultaneous sampling of velocity and density at rates to 100 kHz and data record lengths to 10 million. Velocity and density power spectra and velocity-density cross spectra are presented for a subsonic jet, an underexpanded screeching jet, and for Mach 1.4 and Mach 1.8 supersonic jets. Software and hardware interfaces were developed to allow computer control of all aspects of the experiment and data acquisition.

  7. Dynamics of macroscopic fluctuations in aqueous systems according to Rayleigh scattering data

    NASA Astrophysics Data System (ADS)

    Belovolova, L. V.; Glushkov, M. V.; Timashev, S. F.

    2015-09-01

    The general question of the existence of macrofluctuations of physical characteristics of aqueous systems are discussed. Using the example of analyzing fluctuations in the Rayleigh scattering of natural untreated water, along with catholyte and anolyte obtained in its electrochemical treatment, the possibility of obtaining of quantitative information on the states and dynamics of changes in such systems is shown. Data on the parameters of oscillations in the Rayleigh light scattering of water catholyte and anolyte immediately after electrolysis, and one and two days after its completion, are presented. Calculations are performed using the general phenomenological approach to analyzing chaotic signals (flicker-noise spectroscopy). Quantitative characteristics that reveal substantial differences in the dynamics of macrofluctuations that develop in the catholyte and anolyte of the studied water are presented.

  8. Velocity and Temperature Measurement in Supersonic Free Jets Using Spectrally Resolved Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Panda, J.; Seasholtz, R. G.

    2004-01-01

    The flow fields of unheated, supersonic free jets from convergent and convergent-divergent nozzles operating at M = 0.99, 1.4, and 1.6 were measured using spectrally resolved Rayleigh scattering technique. The axial component of velocity and temperature data as well as density data obtained from a previous experiment are presented in a systematic way with the goal of producing a database useful for validating computational fluid dynamics codes. The Rayleigh scattering process from air molecules provides a fundamental means of measuring flow properties in a non-intrusive, particle free manner. In the spectrally resolved application, laser light scattered by the air molecules is collected and analyzed using a Fabry-Perot interferometer (FPI). The difference between the incident laser frequency and the peak of the Rayleigh spectrum provides a measure of gas velocity. The temperature is measured from the spectral broadening caused by the random thermal motion and density is measured from the total light intensity. The present point measurement technique uses a CW laser, a scanning FPI and photon counting electronics. The 1 mm long probe volume is moved from point to point to survey the flow fields. Additional arrangements were made to remove particles from the main as well as the entrained flow and to isolate FPI from the high sound and vibration levels produced by the supersonic jets. In general, velocity is measured within +/- 10 m/s accuracy and temperature within +/- 10 K accuracy.

  9. An equipment for Rayleigh scattering of Mössbauer radiation

    NASA Astrophysics Data System (ADS)

    Enescu, S. E.; Bibicu, I.; Zoran, V.; Kluger, A.; Stoica, A. D.; Tripadus, V.

    1998-07-01

    A personal computer driven equipment designed for Rayleigh scattering of Mössbauer radiation experiments at room temperature is described. The performances of the system were tested using like scatterers crystals with different mosaic divergences: lithium fluoride (LiF) and pyrolytic graphite (C). The equipment, suitable for any kind of Mössbauer scattering experiments, permits low and adjustable horizontal divergences of the incident beam. On décrit un équipement dédié aux mesures de diffusion Rayleigh de la radiation Mössbauer controlée par ordinateur. Les performances du système ont été testées sur des cristaux ayant des divergences de mosaïque différentes: le fluorure de lithium (LiF) et le graphite pyrolytique (C). L'équipement, qui peut être utilisé dans des différents types d'expérimentations basées sur la diffusion de la radiation Mössbauer, admet des divergences horizontales du faisceau incident faibles et réglables.

  10. Multiple Point Dynamic Gas Density Measurements Using Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard; Panda, Jayanta

    1999-01-01

    A nonintrusive technique for measuring dynamic gas density properties is described. Molecular Rayleigh scattering is used to measure the time-history of gas density simultaneously at eight spatial locations at a 50 kHz sampling rate. The data are analyzed using the Welch method of modified periodograms to reduce measurement uncertainty. Cross-correlations, power spectral density functions, cross-spectral density functions, and coherence functions may be obtained from the data. The technique is demonstrated using low speed co-flowing jets with a heated inner jet.

  11. Laser Rayleigh-Scattering During Space Shuttle Entry

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.

    1989-01-01

    Report presents detailed study of capabilities and requirements for equipment of proposed ultraviolet Rayleigh-scattering instrument to be carried aboard Space Shuttle. Density of atmosphere around flightpath measured. With accuracy and resolution, measurements adequate for detection of small-scale meteorological structure affecting analysis of flight dynamic data of reentering spacecraft. Also discusses extensions of concept to measurements of location of, and density as function of position in, shock wave of Space Shuttle. Measurements provide baseline data for verification of computer models of high-enthalpy hypersonic, nonequilibrium, and viscous conditions.

  12. Analytical evaluation of atomic form factors: Application to Rayleigh scattering

    SciTech Connect

    Safari, L.; Santos, J. P.; Amaro, P.; Jänkälä, K.; Fratini, F.

    2015-05-15

    Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wave functions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.

  13. Spatially-and Temporally-Resolved Multi-Parameter Interferometric Rayleigh Scattering System and Method

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel (Inventor); Cutler, Andrew D. (Inventor); Danehy, Paul M. (Inventor)

    2015-01-01

    A system that simultaneously measures the translational temperature, bulk velocity, and density in gases by collecting, referencing, and analyzing nanosecond time-scale Rayleigh scattered light from molecules is described. A narrow-band pulsed laser source is used to probe two largely separated measurement locations, one of which is used for reference. The elastically scattered photons containing information from both measurement locations are collected at the same time and analyzed spectrally using a planar Fabry-Perot interferometer. A practical means of referencing the measurement of velocity using the laser frequency, and the density and temperature using the information from the reference measurement location maintained at constant properties is provided.

  14. Intracavity Rayleigh/Mie Scattering for Multipoint, Two-Component Velocity Measurement

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.

    2006-01-01

    A simultaneous multi-point two-component Doppler velocimeter is described. The system uses two optical cavities: a Fabry-Perot etalon and an optical cavity for collecting and re-circulating the Rayleigh/Mie scattered light that is collected from the measurement volume in two parallel, but opposite directions. Single-pulse measurements of two orthogonal components of the velocity vector in a supersonic free jet were performed to demonstrate the technique. The re-circulation of the light rejected by the interferometer input mirror also increased the signal intensity by a factor of 3.5. 2005 Optical Society of America Interferometric Rayleigh scattering has previously been used for single-point velocity measurements in unseeded gas flow. However, this past work has generally been limited to probing with continuous-wave lasers resulting in time-averaged measurements of velocity. Multiple velocity components have been measured simultaneously by separate instruments.1,2 It has also been demonstrated that two orthogonal velocity components can be measured simultaneously at one point using one interferometer by reflecting back the probing laser beam, although this approach results in directional ambiguity of the flow velocity vector.3 This measurement ambiguity was removed by prior knowledge of the approximate magnitude and sign of the velocity components. Furthermore, it was shown that multiple points could be measured simultaneously with a Rayleigh scattering interferometric approach, but only one component of velocity was measured.4 Another method of performing multiple component velocity measurements with Rayleigh scattering uses a pair of cameras to image the flow, one of which views the flow through an iodine gas filter. This iodine-filter technique has the advantage of allowing high-resolution velocity imaging, but it generally has a lower dynamic range.

  15. Gamma irradiation effect on Rayleigh scattering in low water peak single-mode optical fibers.

    PubMed

    Wen, Jianxiang; Peng, Gang-Ding; Luo, Wenyun; Xiao, Zhongyin; Chen, Zhenyi; Wang, Tingyun

    2011-11-01

    The Rayleigh scattering loss in low water peak single-mode optical fibers under varying Gamma rays irradiation has been investigated. We observed that the Rayleigh scattering coefficient (CR) of the fiber is almost linearly increased with the increase of Gamma irradiation in the low-dose range (< 500 Gy). Based on the electron spin resonance (ESR) spectra analysis, we confirmed that the Rayleigh scattering mainly results from the irradiation-induced defect centers associated with electron transfer or charge density redistribution around Ge and O atoms. This work provides a new interpretation of the optical loss and reveals a new mechanism on irradiation influence on Rayleigh scattering. PMID:22109205

  16. Angular distribution of light scattered from heavily doped silica fibres

    SciTech Connect

    Alekseev, V V; Likhachev, M E; Bubnov, M M; Salganskii, M Yu; Khopin, V F; Gur'yanov, Aleksei N; Dianov, Evgenii M

    2011-10-31

    This paper describes an experimental setup for precision measurements of the angular distribution of light scattered by optical fibres in a wide angular range and demonstrates that the models of anomalous scattering proposed to date need to be refined. We have found and interpreted a discrepancy between the Rayleigh scattering coefficients measured by different techniques.

  17. Single-pulse Multi-point Multi-component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.; Gaffney, Richard L., Jr.; Cutler, Andrew W.

    2006-01-01

    A simultaneous multi-point, multi-component velocimeter using interferometric detection of the Doppler shift of Rayleigh, Mie, and Rayleigh-Brillouin scattered light in supersonic flow is described. The system uses up to three sets of collection optics and one beam combiner for the reference laser light to form a single collimated beam. The planar Fabry-Perot interferometer used in the imaging mode for frequency detection preserves the spatial distribution of the signal reasonably well. Single-pulse multi-points measurements of up to two orthogonal and one non-orthogonal components of velocity in a Mach 2 free jet were performed to demonstrate the technique. The average velocity measurements show a close agreement with the CFD calculations using the VULCAN code.

  18. Instantaneous 2D Velocity and Temperature Measurements in High Speed Flows Based on Spectrally Resolved Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1995-01-01

    A Rayleigh scattering diagnostic for high speed flows is described for the simultaneous, instantaneous measurement of gas temperature and velocity at a number (up to about one hundred) of locations in a plane illuminated by an injection-seeded, frequency doubled Nd:YAG laser. Molecular Rayleigh scattered light is collected and passed through a planar mirror Fabry-Perot interferometer. The resulting image is analyzed to determine the gas temperature and bulk velocity at each of the regions. The Cramer Rao lower bound for measurement uncertainty is calculated. Experimental data is presented for a free jet and for preliminary measurements in the Lewis 4 inch by 10 inch supersonic wind tunnel.

  19. Factors Influencing Light Scattering in the Eye

    NASA Astrophysics Data System (ADS)

    Ikaunieks, G.; Ozolinsh, M.; Stepanovs, A.; Lejiete, V.; Reva, N.

    2009-01-01

    Our vision in the twilight or dark is strongly affected by the intraocular light scattering (straylight). Of especial importance is to assess this phenomenon in view of the night driving. The authors have studied the spectral dependence of retinal stray-light and estimated the possibility to reduce it with yellow filters and small apertures. For the measurements the direct compensation flicker method was used. The results show that this spectral dependence is close to Rayleigh's scattering (∝λ-4). As could be expected from the known data, the yellow filter should reduce retinal straylight, especially for blue light. However, in the experiments this scattering was not removed with such a filter but instead slightly increased. The optical apertures reduced light scattering in the eye, especially for red color.

  20. Direct-View Multi-Point Two-Component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Gaffney, Richard L., Jr.; Cutler, Andrew D.

    2008-01-01

    This paper describes an instantaneous velocity measurement system based on the Doppler shift of elastically scattered laser light from gas molecules (Rayleigh scattering) relative to an incident laser. The system uses a pulsed laser as the light source, direct-viewing optics to collect the scattered light, an interferometer to analyze spectrally the scattered light mixed with the incident laser light, and a CCD camera to capture the resulting interferogram. The system is capable of simultaneous, spatially (approximately 0.2 mm(exp 3)) and temporally (approximately 40 ns) resolved, multiple point measurements of two orthogonal components of flow velocity in the presence of background scattered light, acoustic noise and vibrations, and flow particulates. Measurements in a large-scale axi-symmetric Mach 1.6 H2-air combustion-heated jet running at a flow sensible enthalpy specific to Mach 5.5 hypersonic flight are performed to demonstrate the technique. The measurements are compared with CFD calculations using a finite-volume discretization of the Favre-averaged Navier-Stokes equations (VULCAN code).

  1. LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES

    SciTech Connect

    Zugger, M. E.; Kane, T. J.; Kasting, J. F.; Williams, D. M.; Philbrick, C. R.

    2010-11-10

    Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 180{sup 0}, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30{sup 0}. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74{sup 0}; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 90{sup 0}, but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.

  2. Molecular Rayleigh Scattering Diagnostic for Dynamic Temperature, Velocity, and Density Measurements

    NASA Technical Reports Server (NTRS)

    Mielke, Amy R.; Elam, Kristie A.; Sung, Chi-Jen

    2006-01-01

    A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations.

  3. Rayleigh Scattering Diagnostic for Measurement of Temperature, Velocity, and Density Fluctuation Spectra

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen; Panda, Jayanta

    2006-01-01

    A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 10 kHz. A high power CW laser beam is focused at a point in a heated air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature, velocity, and density of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 10 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. Power spectral density calculations of temperature, velocity, and density fluctuations, as well as mean and fluctuating quantities are demonstrated for various radial locations in the jet flow at a fixed axial distance from the jet exit plane. Results are compared with constant current anemometry and pitot probe measurements at the same locations.

  4. Beyond the classical Rayleigh limit with twisted light.

    PubMed

    Tong, Zhisong; Korotkova, Olga

    2012-07-01

    It is shown that twisted stochastic light can serve as illumination that may produce images with a resolution overcoming the Rayleigh limit by an order of magnitude. This finding is illustrated for an isoplanatic axially symmetric system with low angular aperture and twisted scalar Gaussian Schell-model illumination. PMID:22743466

  5. Coherent Rayleigh-Brillouin scattering as a flow diagnostic technique

    SciTech Connect

    Graul, J. S.; Lilly, T. C.

    2014-12-09

    Broadband coherent Rayleigh-Brillouin scattering (CRBS) was used to measure translational gas temperatures for nitrogen at the ambient pressure of 0.8 atm using a purpose-built Fabry-Perot etalon spectrometer. Temperatures derived from the CRBS spectral analysis were compared with experimentally-measured temperatures, and were found to be, on average, within 2% of the experimentally-measured value. Axial flow velocities from a double jet at a pressure ratio of 0.38 were also measured by looking at the Doppler shift of the CRBS line shape. With recent developments in chirped laser technology and the capacity of CRBS to simultaneously provide thermodynamic and bulk flow information, the CRBS line shape acquisition and analysis technique presented here may allow for future time-resolved, characterization of aerospace flows.

  6. Characterization of a Combined CARS and Interferometric Rayleigh Scattering System

    NASA Technical Reports Server (NTRS)

    Tedder, Sarah A.; Bivolaru, Daniel; Danehy, Paul M.; Weikl, M. C.; Beyrau, F.; Seeger, T.; Cutler, Andrew D.

    2007-01-01

    This paper describes the characterization of a combined Coherent anti-Stokes Raman Spectroscopy and Interferometric Rayleigh Scattering (CARS-IRS) system by reporting the accuracy and precision of the measurements of temperature, species mole fraction of N2, O2, and H2, and two-components of velocity. A near-adiabatic H2-air Hencken burner flame was used to provide known properties for measurements made with the system. The measurement system is also demonstrated in a small-scale Mach 1.6 H2-air combustion-heated supersonic jet with a co-flow of H2. The system is found to have a precision that is sufficient to resolve fluctuations of flow properties in the mixing layer of the jet.

  7. Dynamic Measurement of Temperature, Velocity, and Density in Hot Jets Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.

    2008-01-01

    A molecular Rayleigh scattering technique was utilized to measure time-resolved gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz. A high power continuous-wave (cw) laser beam was focused at a point in an air flow field and Rayleigh scattered light was collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultipler tubes operated in the photon counting mode allowed high frequency sampling of the total signal level and the circular interference pattern to provide time-resolved density, temperature, and velocity measurements. Mean and rms velocity and temperature, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at the NASA Glenn Research Center (GRC). The Rayleigh measurements are compared with particle image velocimetry data and CFD predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.

  8. Dynamic Measurement of Temperature, Velocity, and Density in Hot Jets Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.

    2009-01-01

    A molecular Rayleigh scattering technique is utilized to measure gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz, providing fluctuation information up to 5 kHz based on the Nyquist theorem. A high-power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultiplier tubes operated in the photon counting mode allow high-frequency sampling of the total signal level and the circular interference pattern to provide dynamic density, temperature, and velocity measurements. Mean and root mean square velocity, temperature, and density, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at NASA John H. Glenn Research Center at Lewis Field. The Rayleigh measurements are compared with particle image velocimetry data and computational fluid dynamics predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.

  9. Dynamic measurement of temperature, velocity, and density in hot jets using Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Mielke, Amy F.; Elam, Kristie A.

    2009-10-01

    A molecular Rayleigh scattering technique is utilized to measure gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz, providing fluctuation information up to 5 kHz based on the Nyquist theorem. A high-power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultiplier tubes operated in the photon counting mode allow high-frequency sampling of the total signal level and the circular interference pattern to provide dynamic density, temperature, and velocity measurements. Mean and root mean square velocity, temperature, and density, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at NASA John H. Glenn Research Center at Lewis Field. The Rayleigh measurements are compared with particle image velocimetry data and computational fluid dynamics predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.

  10. Scattering in the atmosphere of Venus. III - Line profiles and phase curves for Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Young, L. D. G.; Kattawar, G. W.

    1977-01-01

    Spectral line profiles, curves of growth, and curves for the equivalent width of a line as a function of Venus phase angle have been computed for a Rayleigh scattering cloud and compared with those for a cloud of isotropic scatterers. The results are very similar for the two kinds of scattering, with the exception of the curves of equivalent width as a function of Venus phase angle. These latter curves exhibit the 'inverse phase effect' and rule out a scale height of the clouds much less than half the scale height of the gas. The optical depth of the clouds is approximately 100.

  11. Scattering in the atmosphere of Venus. Line profiles and phase curves for Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Young, L. D. G.; Kattawar, G. W.

    1976-01-01

    Spectral line profiles, curves of growth, and curves for the equivalent width of a line as a function of Venus phase angle are computed for a Rayleigh scattering cloud and compared with those for a cloud of isotropic scatterers. The results are similar for the two kinds of scattering, with the exception for the curves of equivalent width as a function of Venus phase angle. These latter curves exhibit the inverse phase effect and rule out the possibility that the scale height of the clouds can be much less than half the scale height of the gas.

  12. Laser light scattering review

    NASA Technical Reports Server (NTRS)

    Schaetzel, Klaus

    1989-01-01

    Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.

  13. Laser light scattering review

    NASA Astrophysics Data System (ADS)

    Schaetzel, Klaus

    1989-08-01

    Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.

  14. Time-Average Measurement of Velocity, Density, Temperature, and Turbulence Using Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Krisie A.; Panda, Jayanta

    2004-01-01

    Measurement of time-averaged velocity, density, temperature, and turbulence in gas flows using a nonintrusive, point-wise measurement technique based on molecular Rayleigh scattering is discussed. Subsonic and supersonic flows in a 25.4-mm diameter free jet facility were studied. The developed instrumentation utilizes a Fabry-Perot interferometer to spectrally resolve molecularly scattered light from a laser beam passed through a gas flow. The spectrum of the scattered light contains information about velocity, density, and temperature of the gas. The technique uses a slow scan, low noise 16-bit depth CCD camera to record images of the fringes formed by Rayleigh scattered light passing through the interferometer. A kinetic theory model of the Rayleigh scattered light is used in a nonlinear least squares fitting routine to estimate the unknown parameters from the fringe images. The ability to extract turbulence information from the fringe image data proved to be a challenge since the fringe is broadened by not only turbulence, but also thermal fluctuations and aperture effects from collecting light over a range of scattering angles. Figure 1 illustrates broadening of a Rayleigh spectrum typical of flow conditions observed in this work due to aperture effects and turbulence for a scattering angle, chi(sub s), of 90 degrees, f/3.67 collection optics, mean flow velocity, u(sub k), of 300 m/s, and turbulent velocity fluctuations, sigma (sub uk), of 55 m/s. The greatest difficulty in processing the image data was decoupling the thermal and turbulence broadening in the spectrum. To aid in this endeavor, it was necessary to seed the ambient air with smoke and dust particulates; taking advantage of the turbulence broadening in the Mie scattering component of the spectrum of the collected light (not shown in the figure). The primary jet flow was not seeded due to the difficulty of the task. For measurement points lacking particles, velocity, density, and temperature

  15. Rayleigh-Gans scattering from polydisperse colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Hobbie, Erik K.; Sung, Lipiin

    1996-10-01

    The scattering of polarized light from a collection of dielectric spheres with model disorder in the particle dimensions is derived in the first Born approximation. The paper is intended as a brief pedagogical review of some of the essential physics behind static light scattering from complex fluids, and attempts to elucidate the natural emergence of the statistical-structure and form factors while emphasizing the role of polydispersity in the particle size. The criterion for the convergence of the Born series is examined. The problem is cast in the language of Fourier transforms and correlation functions at a level that should be accessible to advanced undergraduates.

  16. Scattering Of Light Nuclei

    SciTech Connect

    Quaglioni, S; Navratil, P; Roth, R

    2009-12-15

    The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.

  17. Fluorescence and Light Scattering

    ERIC Educational Resources Information Center

    Clarke, Ronald J.; Oprysa, Anna

    2004-01-01

    The aim of the mentioned experiment is to aid students in developing tactics for distinguishing between signals originating from fluorescence and light scattering. Also, the experiment provides students with a deeper understanding of the physicochemical bases of each phenomenon and shows that the techniques are actually related.

  18. Time-Average Molecular Rayleigh Scattering Technique for Measurement of Velocity, Denisty, Temperature, and Turbulence Intensity in High Speed Nozzle Flows

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Kristie A.; Panda, Jayanta

    2004-01-01

    A molecular Rayleigh scattering based flow diagnostic is developed to measure time average velocity, density, temperature, and turbulence intensity in a 25.4-mm diameter nozzle free jet facility. The spectrum of the Rayleigh scattered light is analyzed using a Fabry-Perot interferometer operated in the static imaging mode. The resulting fringe pattern containing spectral information of the scattered light is recorded using a low noise CCD camera. Nonlinear least squares analysis of the fringe pattern using a kinetic theory model of the Rayleigh scattered light provides estimates of density, velocity, temperature, and turbulence intensity of the gas flow. Resulting flow parameter estimates are presented for an axial scan of subsonic flow at Mach 0.95 for comparison with previously acquired pitot tube data, and axial scans of supersonic flow in an underexpanded screeching jet. The issues related to obtaining accurate turbulence intensity measurements using this technique are discussed.

  19. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre

    NASA Astrophysics Data System (ADS)

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-06-01

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre’s intrinsically higher Rayleigh scatter signal.

  20. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre

    PubMed Central

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-01-01

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre’s intrinsically higher Rayleigh scatter signal. PMID:26077365

  1. Spatially and Temporally-Resolved Multi-Parameter Interferometric Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.

    2011-01-01

    A novel approach to simultaneously measure the translational temperature, bulk velocity, and density in gases by collecting, referencing, and analyzing nanosecond time-scale Rayleigh scattered light from molecules is described. A narrow-band pulsed laser source is used to probe two largely separated measurement locations, one of which is used for reference. The elastically scattered photons containing information from both measurement locations are collected at the same time and analyzed spectrally using a planar Fabry - Perot interferometer. A practical means of referencing the measurement of velocity using the laser frequency, and the density and temperature using the information from the reference measurement location maintained at constant properties is described. To demonstrate the technique single-shot spectra of elastic scattered light are obtained in a near zero velocity H2-air Hencken burner flame and simultaneously in an N2-filled gas cell. A simplified Gaussian distribution model to the scattered light spectra is used to obtain the flame properties. Corrections to this model are applied at lower gas temperatures when the simplified Gaussian approximation is no longer suitable. The near-zero measured velocity as a function of the measured flame temperature, and a comparison of the measured flame density and temperature with the perfect gas law are presented.

  2. The application of laser Rayleigh scattering to gas density measurements in hypersonic helium flows

    NASA Technical Reports Server (NTRS)

    Hoppe, J. C.; Honaker, W. C.

    1979-01-01

    Measurements of the mean static free-stream gas density have been made in two Langley Research Center helium facilities, the 3-inch leg of the high-Reynolds-number helium complex and the 22-inch hypersonic helium tunnel. Rayleigh scattering of a CW argon ion laser beam at 514.5 nm provided the basic physical mechanism. The behavior of the scattered signal was linear, confirmed by a preliminary laboratory study. That study also revealed the need to introduce baffles to reduce stray light. A relatively simple optical system and associated photon-counting electronics were utilized to obtain data for densities from 10 to the 23rd to 10 to the 25th per cu m. The major purpose, to confirm the applicability of this technique in the hypersonic helium flow, was accomplished.

  3. Imaging of Passive Scalar Fields by Filtered Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Kearney, Sean; Grasser, Thomas; Beresh, Steven; Schefer, Robert

    2002-11-01

    Filtered Rayleigh Scattering (FRS) is a molecular-filter-based, laser-diagnostic approach for multiparameter flowfield imaging that has been gaining popularity over the past 5-10 years [1]. Advantages of FRS for noninvasive gas-phase imaging include: (1) elimination of particle or chemical seeding requirements, (2) increased optical noise rejection allowing imaging close to walls and in "dirty" laboratory environments, (3) imaging of multiple flowfield parameters with a single diagnostic. In this work, the construction and performance of a FRS optical system for passive scalar imaging at Sandia National Laboratories is presented. Data were obtained in an open lab where no special precautions for the elimination of room particulate were made. Results from nonreacting jets and from a premixed flame are shown. Temperature imaging in a nonreacting, steady calibration jet reveals the precision of the time-averaged FRS thermometry results to be ±20 K, or 4of the characteristic temperature difference, while the single-laser-pulse precision is degraded to approximately ±40-50 K. These results are adequate for combustion thermometry purposes. Relative to the jet temperature measurements, species concentration imaging of a buoyant helium jet displays increased signal dynamic range and further improved precision. Reacting flow measurements from the combustion-product region of a methane-air Hencken-type premixed flame are also presented and a comparison of FRS and coherent anti-Stokes Raman scattering (CARS) experiments to calculated adiabatic-equilibrium product temperatures is made which validates the suitability of our FRS instrument for combustion temperature imaging. [1]G.S. Elliott, N. Glumac, and C.D. Carter, Meas. Sci. Tech., 12, 452, 2001.

  4. Investigation of Condensation/Clustering Effects on Rayleigh Scattering Measurements in a Hypersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Tyler, Charles

    1996-01-01

    Rayleigh scattering, a nonintrusive measurement technique for the measurement of density in a hypersonic wind tunnel, is under investigation at Wright Laboratory's Mach 6 wind tunnel. Several adverse effects, i.e., extraneous scatter off walls and windows, hinder Rayleigh scattering measurements. Condensation and clustering of flow constituents also present formidable obstacles. Overcoming some of these difficulties, measurements have been achieved while the Mach 6 test section was pumped down to a vacuum, as well as for actual tunnel operation for various stagnation pressures at fixed stagnation temperatures. Stagnation pressures ranged from 0.69 MPa to 6.9 MPa at fixed stagnation temperatures of 511, 556, and 611 K. Rayleigh scatter results show signal levels much higher than expected for molecular scattering in the wind tunnel. Even with higher than expected signals, scattering measurements have been made in the flowfield of an 8-degree half-angle blunt nose cone with a nose radius of 1.5 cm.

  5. Multiple scattered radiation emerging from Rayleigh and continental haze layers. I - Radiance, polarization, and neutral points

    NASA Technical Reports Server (NTRS)

    Kattawar, G. W.; Plass, G. N.; Hitzfelder, S. J.

    1976-01-01

    The matrix operator method was used to calculate the polarization of radiation scattered on layers of various optical thicknesses, with results compared for Rayleigh scattering and for scattering from a continental haze. In both cases, there are neutral points arising from the zeros of the polarization of single scattered photons at scattering angles of zero and 180 degrees. The angular position of these Rayleigh-like neutral points (RNP) in the sky shows appreciable variation with the optical thickness of the scattering layer for a Rayleigh phase matrix, but only a small variation for haze L phase matrix. Another type of neutral point exists for non-Rayleigh phase functions that is associated with the zeros of the polarization for single scattering which occurs between the end points of the curve. A comparison of radiances calculated from the complete theory of radiative transfer using Stokes vectors with those obtained from the scalar theory shows that differences of the order of 23% may be obtained for Rayleigh scattering, while the largest difference found for a haze L phase function was of the order of 0.1%.

  6. Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.

    1999-01-01

    The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.

  7. Suppression of Rayleigh scattering noise in sodium laser guide stars by hyperfine depolarization of fluorescence.

    PubMed

    Guillet de Chatellus, Hugues; Moldovan, Ioana; Fesquet, Vincent; Pique, Jean-Paul

    2006-11-27

    We propose what we believe is a novel method for enabling the complete suppression of noise due to Rayleigh scattering in sodium laser guide star systems by means of selective discrimination between Rayleigh and fluorescence signals based on polarization properties. We show that, contrary to the nearly 100% polarized Rayleigh scattering, fluorescence from the D(2) sodium line is strongly depolarized under excitation by a modeless laser. This offers the possibility of completely cancelling the effects of the Rayleigh scattering background while preserving the fluorescence signal to about 40% of its maximal value, leading to an improvement of the signal-to-noise ratio by several orders of magnitude. Both theoretical and experimental data confirm this new proposal. PMID:19529568

  8. Use of two profilers during MCTEX for unambiguous identification of Bragg scattering and Rayleigh scattering

    SciTech Connect

    Gage, K.S.; Williams, C.R.; Ecklund, W.L.; Johnston, P.E.

    1999-11-01

    A 2835-MHz (10.6-cm wavelength) profiler and a 920-MHz (32.6-cm wavelength) profiler were collocated by the NOAA Aeronomy Laboratory at Garden Point, Australia, in the Tiwi Islands during the Maritime Continent Thunderstorm Experiment (MCTEX) field campaign in November and December 1995. The two profilers were directed vertically and observed vertical velocities in the clear atmosphere and hydrometeor fall velocities in deep precipitating cloud systems. In the absence of Rayleigh scatterers, the profilers obtain backscattering from the refractive index irregularities created from atmospheric turbulence acting upon refractive index gradients. This kind of scattering is commonly referred to as Bragg scattering and is only weakly dependent on the radar wavelength provided the radar half-wavelength lies within the inertial subrange of homogeneous, isotropic turbulence. In the presence of hydrometeors the profilers observe Rayleigh backscattering from hydrometeors much as weather radars do and this backscatter is very dependent upon radar wavelength, strongly favoring the shorter wavelength profiler resulting in a 20-dB enhancement of the ability of the 2835-MHz profiler to observe hydrometeors. This paper presents observations of equivalent reflectivity, Doppler velocity, and spectral width made by collocated profilers during MCTEX. Differential reflectivity is used to diagnose the type of echo observed by the profilers in the spectral moment data.

  9. Light Scattering by Spheroids

    NASA Astrophysics Data System (ADS)

    Xie, Ya-Ming; Ji, Xia

    Nowadays, with the development of technology, particles with size at nanoscale have been synthesized in experiments. It is noticed that anisotropy is an unavoidable problem in the production of nanospheres. Besides, nonspherical nanoparticles have also been extensively used in experiments. Comparing with spherical model, spheroidal model can give a better description for the characteristics of nonspherical particles. Thus the study of analytical solution for light scattering by spheroidal particles has practical implications. By expanding incident, scattered, and transmitted electromagnetic fields in terms of appropriate vector spheroidal wave functions, an analytic solution is obtained to the problem of light scattering by spheroids. Unknown field expansion coefficients can be determined with the combination of boundary conditions and rotational-translational addition theorems for vector spheroidal wave functions. Based on the theoretical derivation, a Fortran code has been developed to calculate the extinction cross section and field distribution, whose results agree well with those obtain by FDTD simulation. This research is supported by the National Natural Science Foundation of China No. 91230203.

  10. Critical fluid light scattering

    NASA Technical Reports Server (NTRS)

    Gammon, Robert W.

    1988-01-01

    The objective is to measure the decay rates of critical density fluctuations in a simple fluid (xenon) very near its liquid-vapor critical point using laser light scattering and photon correlation spectroscopy. Such experiments were severely limited on Earth by the presence of gravity which causes large density gradients in the sample when the compressibility diverges approaching the critical point. The goal is to measure fluctuation decay rates at least two decades closer to the critical point than is possible on earth, with a resolution of 3 microK. This will require loading the sample to 0.1 percent of the critical density and taking data as close as 100 microK to the critical temperature. The minimum mission time of 100 hours will allow a complete range of temperature points to be covered, limited by the thermal response of the sample. Other technical problems have to be addressed such as multiple scattering and the effect of wetting layers. The experiment entails measurement of the scattering intensity fluctuation decay rate at two angles for each temperature and simultaneously recording the scattering intensities and sample turbidity (from the transmission). The analyzed intensity and turbidity data gives the correlation length at each temperature and locates the critical temperature. The fluctuation decay rate data from these measurements will provide a severe test of the generalized hydrodynamic theories of transport coefficients in the critical regions. When compared to equivalent data from binary liquid critical mixtures they will test the universality of critical dynamics.

  11. Determination of surface normal temperature gradients using thermographic phosphors and filtered Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Brübach, J.; Zetterberg, J.; Omrane, A.; Li, Z. S.; Aldén, M.; Dreizler, A.

    2006-09-01

    Wall temperature as well as the temperature distribution within or close-by the boundary layer of an electrically heated axisymmetric jet impinging on a flat plate were monitored to deduce wall-normal temperature gradients. The radial surface temperature profile of the plate was determined by coating it with thermographic phosphors (TPs), materials whose phosphorescence decay time is dependent on their temperature. The TP was excited electronically by a frequency-tripled Nd:YAG laser (355 nm) and the temporal decay of the phosphorescence intensity was measured zero-dimensionally by a photomultiplier tube. In this case the 659-nm emission line of Mg3F2GeO4:Mn was monitored. The non-intrusive measurement of gas temperatures near the surface was performed two-dimensionally by filtered Rayleigh scattering (FRS). A tunable frequency-tripled single-longitudinal-mode alexandrite laser beam at 254 nm was formed into a light sheet pointing parallel to the surface. The scattered light was imaged through a very narrow linewidth atomic mercury filter onto an intensified charged coupled device (ICCD). The elastic stray light from surfaces was strongly suppressed, whereas Doppler-broadened light was detected. Thermographic phosphors proved to be reliable for the measurement of surface temperatures. Dependent on the specific experimental conditions, problems appeared with signals interfering with the FRS radiation close-by the surface. Results and challenges of this approach are discussed.

  12. Feasibility of Rayleigh Scattering Flow Diagnostics in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.; Lee, Joseph W.; Goad, William K.

    2015-01-01

    Laser-based Rayleigh light scattering (RLS) was performed in the National Transonic Facility (NTF) at NASA Langley Research Center. The goal was to determine if the free-stream flow undergoes clustering (early stage of condensation from gas to liquid) or remains in a pure diatomic molecular phase. Data indicate that clusters are not observable down to levels of 10% of the total light scatter for a variety of total pressures at one N2 cryogenic-mode total temperature (Tt = -50 F = 227 K) and one air-mode temperature (Tt = +130 F = 327 K). Thus RLS appears viable as a qualitative or quantitative diagnostic for flow density in NTF in the future. Particles are distinguished from optically unresolvable clusters because they are much larger and individually resolvable in the laser beam image with Mie scattering. The same RLS apparatus was also used, without modification, to visualize naturally occurring particles entrained in the flow for both cryogenic and air-modes. Estimates of the free-stream particle flux are presented, which may be important for interpretation of laminar-to-turbulent boundary-layer transition studies. 1

  13. The development of a tunable, single-frequency ultraviolet laser source for UV filtered Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Finkelstein, N.; Gambogi, J.; Lempert, Walter R.; Miles, Richard B.; Rines, G. A.; Finch, A.; Schwarz, R. A.

    1995-01-01

    We present the development of a flexible, high power, narrow line width, tunable ultraviolet source for diagnostic application. By frequency tripling the output of a pulsed titanium-sapphire laser, we achieve broadly tunable (227-360 nm) ultraviolet light with high quality spatial and spectral resolution. We also present the characterization of a mercury vapor cell which provides a narrow band, sharp edge absorption filter at 253.7 nm. These two components form the basis for the extension of the Filtered Rayleigh Scattering technique into the ultraviolet. The UV-FRS system is comprised of four pieces: a single frequency, cw tunable Ti:Sapphire seeding source; a high-powered pulsed Ti:Sapphire oscillator; a third harmonic generator system; and an atomic mercury vapor filter. In this paper we discuss the development and characterization of each of these elements.

  14. Rayleigh scattering as a probe of higher-order mode propagation in an optical nanofiber

    NASA Astrophysics Data System (ADS)

    Fatemi, Fredrik K.; Hoffman, Jonathan E.; Beadie, Guy; Rolston, Steven L.; Orozco, Luis A.

    2015-05-01

    Optical nanofibers can have large evanescent fields that create strong interactions with atoms. To increase the complexity of the potential landscape, recent studies have explored the use of higher-order modes. However, with several propagating modes in the nanofiber, the challenge remains of controlling the field distribution on the nanofiber waist. Here, we describe imaging Rayleigh scattered light to analyze the spatial evolution of the propagating fields throughout the entire nanofiber, including the transition from core-cladding guidance to cladding-air guidance. By measuring local beat lengths between higher-order modes in situ, we identify and systematically control the modal composition. These measurements also provide a non-destructive tool for determining variations in the waist radius to below 3 nm using entirely optical means. Funded by ONR, the ARO Atomtronics MURI, DARPA, and the NSF through the PFC at JQI.

  15. A method of atmospheric density measurements during space shuttle entry using ultraviolet-laser Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.

    1988-01-01

    An analytical study and its experimental verification are described which show the performance capabilities and the hardware requirements of a method for measuring atmospheric density along the Space Shuttle flightpath during entry. Using onboard instrumentation, the technique relies on Rayleigh scattering of light from a pulsed ArF excimer laser operating at a wavelength of 193 nm. The method is shown to be capable of providing density measurements with an uncertainty of less than 1 percent and with a spatial resolution along the flightpath of 1 km, over an altitude range from 50 to 90 km. Experimental verification of the signal linearity and the expected signal-to-noise ratios is demonstrated in a simulation facility at conditions that duplicate the signal levels of the flight environment.

  16. A method of atmospheric density measurements during Shuttle entry using UV laser Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.

    1987-01-01

    A detailed study is described of the performance capabilities and the hardware requirements for a method in which ambient density is measured along the Space Shuttle flight path using on-board optical instrumentation. The technique relies on Rayleigh scattering of light from a pulsed, ultraviolet, ArF excimer laser operating at a wavelength of 193 nm. The method is shown to be capable of providing direct measurements of ambient density with an uncertainty of less than 1 percent and with a spatial resolution of 1 km, over an altitude range from 50 to 90 km. In addition, extensions of this concept are discussed that allow measurements of the shock wave location and the density profile within the shock layer. Two approaches are identified that appear to be feasible, in which the same laser system is used for the extended measurements as that required for the ambient density measurements.

  17. Quantitative Rayleigh thermometry for high background scattering applications with structured laser illumination planar imaging.

    PubMed

    Kempema, Nathan J; Long, Marshall B

    2014-10-10

    This work demonstrates structured laser illumination planar imaging (SLIPI) for Rayleigh thermometry with high background scattering. Two coherent laser beams were crossed to produce an interference pattern, from which the modulated Rayleigh signal was collected. The modulated signal serves as a signature that identifies information about Rayleigh scattering from the probe volume against additional contributions in the image from background scattering. This work shows that the structured nature of the illumination allows for a simplified background correction. The experimental approach is validated in a non-premixed methane/air flame, and the temperature is found to be in excellent agreement with previous experimental and computational results. Rayleigh SLIPI is then applied to a high background scattering application as part of the full-field temperature measurement of sooting non-premixed ethylene/air flames. For these flames, standard Rayleigh background corrections are impossible since scattering from soot just outside the field of view is the main source of the background. Good agreement is found between SLIPI and intensity-ratio thin-filament pyrometry-derived temperature along their adjoining interface in the flame. PMID:25322370

  18. A High Performance Computing approach to model multiple Rayleigh scattering in the Earth atmosphere

    NASA Astrophysics Data System (ADS)

    Franssens, Ghislain; Dekemper, Emmanuel; Mateshivili, Nina; Vanhellemont, filip; fussen, didier; pieroux, didier

    2016-04-01

    The retrieval of atmospheric trace gases and aerosols in the Earth atmosphere from light scattering measurements typically involves an iterative inversion algorithm. A key part of this algorithm is its forward model, which takes care of calculating the amount of light that the remote sensing instrument will see, for any assumed atmosphere composition. The forward model is usually an atmospheric radiative transfer code. It is a serious challenge for a radiative transfer code to be, at the same time, sufficiently accurate and sufficiently fast, so that it can be included in the iterative retrieval loop of an operational service. An accurate code must be able to calculate multiple Rayleigh scattering (important in the UV and/or at lower altitudes) by the air in a spherical atmosphere. This is something that currently only a Monte Carlo algorithm can do. However, any Monte Carlo code is far too slow to be included in the retrieval loop, even if we make use of the currently available HPC power. We report some first results that were obtained by a new solution to this old problem. We first use a HPC cluster to tabulate multiple Rayleigh scattering in a standard Earth atmosphere, using a Monte Carlo code, as function of 6 parameters (albedo, view zenith angle, solar zenith angle, relative azimuth angle, altitude and wavelength). Then, a well chosen empirical function is fitted on the tabulated data. From this function, correction factors are derived and appropriately inserted in a fast single scattering algorithm, which so effectively becomes a multiple scattering algorithm. Since the evaluation of the empirical function is also very fast, we end up with a radiative transfer code that is both accurate and sufficiently fast for operational data production. Our conclusion is that commonly available and affordable HPC systems can still not directly solve the retrieval problem with sufficient accuracy in real time. However, the above described two step approach now becomes

  19. Planar Rayleigh Scattering Results in Helium/Air Mixing Experiments in a Mach 6 Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Shirinzadeh, B.; Balla, R. Jeffrey; Hillard, M. E.; Anders, J. B.; Exton, R. J.; Waitz, I. A.

    1991-01-01

    Planar Rayleigh scattering measurements using an ArF-excimer laser have been performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach 6facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross sectional area (5 cm by 10 cm) of the flow field in the absence of clusters.

  20. Light Scattering and Intermediate Range Order in Glasses: Nanoscale Inhomogeneities.

    NASA Astrophysics Data System (ADS)

    Schroeder, John; Kratzer, Joseph H.; Moynihan, Cornelius T.; Hwa, Luu-Gen

    2002-03-01

    Light scattering from oxide and halide glasses at temperatures up to the glass transition region exhibits anomalous Rayleigh scattering. In all glasses a hysteresis effect is seen in the Rayleigh scattering intensity behavior when heating and cooling experiments are compared. This hysteresis effect in the Rayleigh scattering is an indication that an intermediate range order exists in these glasses. Measurements of the Boson peak, a low lying Raman line that is intrinsic to all glass systems, located about 20/cm to 110/cm from the exciting line frequency are identified with the existence of intermediate range order in glass. Large pressure induced changes in the Boson peak frequency location are observed and predicted from existing theory. The non-coincidence effect, a comparison of the Boson peak maximum location for isotropic versus anisotropic spectra, gives additional evidence that glasses have tendencies to form intermediate range order. This intermediate range order or nanoscale inhomogeneities extend from about two to five nanometers in size for the glasses under consideration. These nanoscale inhomogeneities will be identified as a possible source for non-exponential structural relaxation kinetics in all glasses. The nature of the Boson peak, the anomalous Rayleigh scattering and non-coincidence effect in glasses, is discussed with respect to their interrelationships in terms of existing theories.

  1. Determination of the quantized topological magneto-electric effect in topological insulators from Rayleigh scattering.

    PubMed

    Ge, Lixin; Zhan, Tianrong; Han, Dezhuan; Liu, Xiaohan; Zi, Jian

    2015-01-01

    Topological insulators (TIs) exhibit many exotic properties. In particular, a topological magneto-electric (TME) effect, quantized in units of the fine structure constant, exists in TIs. Here, we theoretically study the scattering properties of electromagnetic waves by TI circular cylinders particularly in the Rayleigh scattering limit. Compared with ordinary dielectric cylinders, the scattering by TI cylinders shows many unusual features due to the TME effect. Two proposals are suggested to determine the TME effect of TIs simply by measuring the electric-field components of scattered waves in the far field at one or two scattering angles. Our results could also offer a way to measure the fine structure constant. PMID:25609462

  2. Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

    SciTech Connect

    Beresh, Steven Jay; Grasser, Thomas W.; Kearney, Sean Patrick; Schefer, Robert W.

    2004-01-01

    Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multi-parameter diagnostics. Within the thermal-fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current engineering sciences capabilities and severely tests the state of the art. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for high-resolution, nonintrusive measurement of gas-phase velocity and temperature. With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within {+-}50 K (3%) in a premixed CH4-air flame and within {+-}100 K for a vortex-strained diluted CH4-air diffusion flame where the FRS technique is severely tested by large variation in scattering cross section. In the diffusion flame work, FRS has been combined with Raman imaging of the CH4 fuel molecule to correct for the local light scattering properties of the combustion gases. To our knowledge, this is the first extension of FRS to nonpremixed combustion and the first use of joint FRS

  3. Molecular Rayleigh Scattering Diagnostic for Measurement of High Frequency Temperature Fluctuations

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.

    2005-01-01

    A novel technique for measurement of high frequency temperature fluctuations in unseeded gas flows using molecular Rayleigh scattering is investigated. The spectrum of laser light scattered from molecules in a gas flow is resolved using a Fabry-Perot interferometer. The width of the spectral peak is broadened by thermal motion of the molecules and hence is related to gas temperature. The interference fringe pattern containing spectral information is divided into four concentric regions using a series of mirrors angled with respect to one another. Light from each of these regions is directed towards photomultiplier tubes and sampled at 10 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows measurement of gas temperature. Independently monitoring the total scattered intensity provides a measure of gas density. This technique also has the potential to simultaneously measure a single component of flow velocity by monitoring the spectral peak location. Measurements of gas temperature and density are demonstrated using a low speed heated air jet surrounded by an unheated air co-flow. Mean values of temperature and density are shown for radial scans across the jet flow at a fixed axial distance from the jet exit plane. Power spectra of temperature and density fluctuations at several locations in the jet are also shown. The instantaneous measurements have fairly high uncertainty; however, long data records provide highly accurate statistically quantities, which include power spectra. Mean temperatures are compared with thermocouple measurements as well as the temperatures derived from independent density measurements. The accuracy for mean temperature measurements was +/- 7 K.

  4. Study of compressible mixing layers using filtered Rayleigh scattering based visualizations

    NASA Technical Reports Server (NTRS)

    Elliott, Gregory S.; Samimy, MO; Arnette, Stephen A.

    1992-01-01

    Filtered Rayleigh scattering-based flow visualizations of compressible mixing layers are reported. The lower compressibility case (Mc = 0.51) displays well-defined roller-type spanwise structures and streamwise streaks. The structures of the high compressibility case (Mc = 0.86) are more 3D and oblique.

  5. Near-resonance-Rayleigh scattering measurement on a resonant laser-driven barium plasma

    SciTech Connect

    Nee, T.A.

    1985-06-01

    Near-resonance-Rayleigh scattering is used as a space-time-resolved density probe on a resonant laser-driven barium plasma. Feasibility of this technique was investigated. Comparison to other methods such as absorption technique is made and found to be consistent.

  6. Adjoint calculations for multiple scattering of Compton and Rayleigh effects

    NASA Astrophysics Data System (ADS)

    Fernández, J. E.; Sumini, M.

    1992-08-01

    As is well known, the experimental determination of the Compton profile requires a particular geometry with a scattering angle close to π. That situation involves a narrow multiple-scattering spectrum that overlaps the Compton peak, making it difficult to analyze the different contributions to the profile. We show how the solution of the adjoint problem can help in devising more useful experimental configurations, giving, through its classical "importance" meaning, a formally clear picture of the whole problem.

  7. Rayleigh-Brillouin scattering studies of thoriated fluoride and fluorozirconate glasses

    SciTech Connect

    Pan, Z.; Wicksted, J.P. )

    1992-01-01

    Rayleigh-Brillouin scattering measurements have been conducted on a thoriated fluoride and a fluorozirconate glass. Values of the elastic and photoelastic constants of these glasses pertaining to the longitudinal and transverse acoustic modes have been determined. In addition, corrections due to absorption have been explicitly included in the calculation of the photoelastic constants. In this paper, the authors note that although fluoride glasses of similar compositions have been previously measured, little or no data on the transverse Brillouin components have been reported, while values of C{sub 44} and P{sub 44} have been determined for both fluoride glasses in our study. Additional results on the Rayleigh scattering losses have also been obtained and indicate smaller scattering losses from the fluorozirconate glass than from the thoriated fluoride glass.

  8. Light Scattering Study of Titania Aerosols

    NASA Astrophysics Data System (ADS)

    Oh, Choonghoon; Sorensen, Chris

    1997-03-01

    We studied the fractal morphology of titania aerosols by light scattering. Titania aerosols were generated by the thermal decomposition of titanium tetraisopropoxide (TTIP) in a silica tube furnace. TTIP was evaporated at temperatures up to 80^circC and its vapor was carried by dry nitrogen to a furnace with temperature in the range of 400 - 600^circC. A TEM analysis of the generated particles showed a typical DLCA structure with a monomer diameter about 50 nm. The particles were then made to flow through a narrow outlet as a laminar stream. The light scattering from these particles was measured using a He-Ne laser as a light source. The measured structure factor clearly showed the Rayleigh, Guinier, and fractal regimes. The fractal morphological parameters, such as the cluster radius of gyration, the fractal dimension, and the fractal prefactor were studied from the structure factor as a function of particle generation conditions. The cluster radius of gyration was about 1 μm and showed a modest dependency on the generation conditions. The fractal dimension was about 1.7 in all cases. These results are in good agreement with the TEM analysis.

  9. Rayleigh Scattering in the Atmosphere of the Warm Exo-Neptune GJ 3470b

    NASA Astrophysics Data System (ADS)

    Dragomir, Diana; Benneke, Björn; Pearson, Kyle A.; Crossfield, Ian J. M.; Eastman, Jason; Barman, Travis; Biddle, Lauren I.

    2015-12-01

    GJ 3470b is a warm Neptune-size planet transiting an M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g, Sloan i, Harris B, and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering in the visible. Our results demonstrate the feasibility of exoplanet atmospheric characterization from the ground, even with meter-class telescopes.

  10. [Determination of Trace Boron Based on Gold Nanorod Plasmonic Resonance Rayleigh Scattering Energy Transfer to the Coordinate].

    PubMed

    Ye, Ling-ling; Li, Ting-sheng; Luo, Yang-he; Wen, Gui-qing; Liang, Ai-hui; Jiang, Zhi-liang

    2015-05-01

    B is a necessary trace element for human and animals, but the excess intake of B caused poison. Thus, it is very important to determination of B in foods and water. The target of this study is development of a new, sensitive and selective resonance Rayleigh scattering energy transfer (RRS-ET) for the determination of B. The combination of energy transfer with resonance Rayleigh scattering (RRS) has developed a new technology called RRS-ET, which can realize selective and sensitive detection of boric acid. The gold nanorods in diameter of 12 nm and length of 37 nm were prepared by the seed growth procedure. In pH 5. 6 NH4 Ac-HAc buffer solution and in the presence of azomethine-H (AMH), the gold nanorod particles exhibited a strong resonance Rayleigh scattering (RRS) peak at 404 nm. In the presence of boric acid, it reacts with AMH to form AMH-boric acid (AMH-B) complexes. When the complexe as a receptor close to the gold nanorod as a donor, the resonance Rayleigh scattering energy transfer (RRS-ET) take placed that resulted in the Rayleigh scattering signal quenching. With the increase of the concentration of boric acid, the formed complexes increased, the scattering light energy of gold nanorod transfer to the complexes increased, resulting in the Rayleigh scattering intensity linearly reduced at 404 nrn. The decreased RRS intensity responds linearly to the concentration of boron over 10~750 ng . mL-1 B, with a regress equation of ΔI404 nm =3. 53c+24 and a detection of 5 ng mL-1 B. The influence of coexistence substances on the RRS-ET determination of 2. 3 X 10(-7) mol . L-1 B was considered in details. Results showed that this new RRS-ET method is of high selectivity, that is, 4 X 10(-4) mol . L-1 Mn2+, Cd2+, Zn2+, Bi+, Na+, Al3+, glucose, Hg2+, IO3-, F-, SO(2-)3, SiO3-, NO3-, CIO4-, H2O2, mannitol, glycerol, and ethylene glycol, 4X 10(-5) mol . L-1 L-tyrosine, and 2 X 10(-4) mol . L-1 L-glutamic acid do not interfere with the determination. Based on this, a new

  11. Standardization of light scattering measurements

    NASA Astrophysics Data System (ADS)

    Schröder, Sven; von Finck, Alexander; Duparré, Angela

    2015-10-01

    In every advanced optical system, light scattering caused by the imperfections of optical components sooner or later becomes an issue that needs to be addressed. Light scattering can be a critical factor for both the throughput and the imaging quality of optical systems. On a component level, the quantities to describe these effects are the scatter loss or total scattering (TS) and the scattering distribution function or angle-resolved light scattering (ARS). In the last decades, a number of instruments have been developed worldwide for the measurement of TS and ARS. However, numerous pitfalls have to be avoided to obtain objective, reliable, and reproducible measurement results. This is, in particular, true for low scatter levels of high-end optical components. Standard procedures that have to be both concise and easy to implement are thus of crucial importance for the optics community. This paper tries to give an overview on existing standards as well as an outlook on new standards that are still being developed. Special emphasis is put on ISO standards jointly developed, reviewed, and revised by the international experts in the field.

  12. Light Scattering From Fractal Titania Aggregates

    NASA Astrophysics Data System (ADS)

    Pande, Rajiv; Sorensen, Christopher M.

    1996-03-01

    We studied the fractal morphology of titania aggregates by light scattering. Titanium dioxide particles were generated by the thermal decomposition of titanium tetra-isopropoxide(TTIP) in a glass furnace at various temperatures in the range of 100 - 500^o C. We scattered vertically polarized He-Ne laser (λ = 6328Ålight from a laminar aerosol stream of particles and measured the optical structure factor. This structure factor shows Rayleigh, Guinier, fractal and Porod regimes. The radius of gyration Rg was determined from the Guinier analysis. The data were then fit to the Fisher-Burford form to determine the fractal dimension of about 2.0. This fit also delineated the crossover from the fractal to Porod regime, which can be used to determine the monomer particle size of about 0.1 μm. These optical measurements will be compared to electron microscope analysis of aggregates collected from the aerosol. This work was supported by NSF grant CTS-9908153.

  13. Rayleigh Scattering Diagnostic Used to Measure Velocity and Density Fluctuation Spectra

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, Jayanta; Elam, Kristie A.

    2003-01-01

    A new, molecular Rayleigh-scattering-based flow diagnostic developed at the NASA Glenn Research Center has been used for the first time to measure the power spectrum of both gas density and radial velocity components in the plumes of high-speed jets. The objective of the work is to develop an unseeded, nonintrusive dynamic measurement technique for studying turbulent flows in NASA test facilities. This technique provides aerothermodynamic data not previously obtainable. It is particularly important for supersonic flows, where hot wire and pitot probes are difficult to use and disturb the flow under study. The effort is part of the nonintrusive instrumentation development program supporting propulsion research at the NASA Glenn Research Center. In particular, this work is measuring fluctuations in flow velocity, density, and temperature for jet noise studies. These data are valuable to researchers studying the correlation of flow fluctuations with far-field noise. One of the main objectives in jet noise research is to identify noise sources in the jet and to determine their contribution to noise generation. The technique is based on analyzing light scattered from molecules within the jet using a Fabry-Perot interferometer operating in a static imaging mode. The PC-based data acquisition system can simultaneously sample velocity and density data at rates to about 100 kHz and can handle up to 10 million data records. We used this system to interrogate three different jet nozzle designs in a Glenn free-jet facility. Each nozzle had a 25.4-mm exit diameter. One was convergent, used for subsonic flow measurements and to produce a screeching underexpanded jet with a fully expanded Mach number of 1.42. The other nozzles (Mach 1.4 and 1.8) were convergent-divergent types. The radial component of velocity and gas density were simultaneously measured in this work.

  14. A Rayleigh Scatter-Based Ocular Flare Analysis Meter for Flare Photometry of the Anterior Chamber

    PubMed Central

    Lam, Deborah L.; Axtelle, Jim; Rath, Susan; Dyer, Andrew; Harrison, Benjamin; Rogers, Claude; Menon, Naresh; Van Gelder, Russell N.

    2015-01-01

    Purpose Existing flare photometers are based on the Tyndall effect, which requires sophisticated laser photometry. The ocular flare analysis meter (OFAM) is a nonlaser photometer that uses quantitative Rayleigh scatter and absorption from visible light to compute a flare value. This study is designed to correlate OFAM measurements with qualitative measurements of flare in vitro and in vivo. Methods Following validation of the device on artificial anterior chambers containing known protein concentrations, flare readings were obtained from 90 subjects (46 with and 44 without uveitis) in one eye. Subjects were graded by the Standardization of Uveitis Nomenclature (SUN) working group flare scoring system and received the OFAM flare measurements. Results The OFAM showed linear response in vitro to protein concentrations ranging from 0 to 0.5 mg/ml. In clinical use in subjects ranging from SUN flare scores of 0+ to 2+, OFAM showed statistically significant measurement accuracy (P = 0.0008 of flare 0 versus flare 2; P = 0.031 of flare 0 versus flare 1). Distinction of SUN scores 1 and 2 was borderline significant (P = 0.057). Conclusion The OFAM photometry correlates with the standard SUN scoring system. This method may provide an objective method to diagnosis and monitor uveitis. Further longitudinal studies are warranted. Translational Relevance Currently, ocular flare is assessed qualitatively in most clinical settings. The existing methodology uses only Tyndall effect to measure flare. The OFAM uses an alternate, nonlaser means for measurement of anterior chamber flare by measure of Raleigh scatter. This pilot clinical study suggests that the OFAM device may be useful in measurement of uveitis activity. PMID:26688778

  15. Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering

    DOE PAGESBeta

    Gerakis, A.; Shneider, M. N.; Stratton, B. C.

    2016-07-21

    Here, we measure the coherent Rayleigh-Brillouin scattering (CRBS) signal integral as a function of the recorded gas pressure in He, Co2, SF6, and air, and confirm the already established quadratic dependence of the signal on the gas density. Finally, we propose the use of CRBS as an effective diagnostic for the remote measurement of gas' density (pressure) and temperature, as well as polarizability, for gases of known composition.

  16. Retrieval of Temperature From a Multiple Channel Rayleigh-Scatter Lidar Using an Optimal Estimation Method

    NASA Astrophysics Data System (ADS)

    Sica, R. J.; Haefele, A.

    2014-12-01

    The measurement of temperature in the middle atmosphere with Rayleigh-scatter lidars is an important technique for assessing atmospheric change. Current retrieval schemes for these temperature have several shortcoming which can be overcome using an optimal estimation method (OEM). OEMs are applied to the retrieval of temperature from Rayleigh-scatter lidar measurements using both single and multiple channel measurements. Forward models are presented that completely characterize the measurement and allow the simultaneous retrieval of temperature, dead time and background. The method allows a full uncertainty budget to be obtained on a per profile basis that includes, in addition to the statistical uncertainties, the smoothing error and uncertainties due to Rayleigh extinction, ozone absorption, the lidar constant, nonlinearity in the counting system, variation of the Rayleigh-scatter cross section with altitude, pressure, acceleration due to gravity and the variation of mean molecular mass with altitude. The vertical resolution of the temperature profile is found at each height, and a quantitative determination is made of the maximum height to which the retrieval is valid. A single temperature profile can be retrieved from measurements with multiple channels that cover different height ranges, vertical resolutions and even different detection methods. The OEM employed is shown to give robust estimates of temperature consistent with previous methods, while requiring minimal computational time. This demonstrated success of lidar temperature retrievals using an OEM opens new possibilities in atmospheric science for measurement integration between active and passive remote sensing instruments. We are currently working on extending our method to simultaneously retrieve water vapour and temperature using Raman-scatter lidar measurements.

  17. Development of Filtered Rayleigh Scattering for Accurate Measurement of Gas Velocity

    NASA Technical Reports Server (NTRS)

    Miles, Richard B.; Lempert, Walter R.

    1995-01-01

    The overall goals of this research were to develop new diagnostic tools capable of capturing unsteady and/or time-evolving, high-speed flow phenomena. The program centers around the development of Filtered Rayleigh Scattering (FRS) for velocity, temperature, and density measurement, and the construction of narrow linewidth laser sources which will be capable of producing an order MHz repetition rate 'burst' of high power pulses.

  18. Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Gerakis, A.; Shneider, M. N.; Stratton, B. C.

    2016-07-01

    We measure the coherent Rayleigh-Brillouin scattering (CRBS) signal integral as a function of the recorded gas pressure in He, Co2, SF6, and air, and we confirm the already established quadratic dependence of the signal on the gas density. We propose the use of CRBS as an effective diagnostic for the remote measurement of gas' density (pressure) and temperature, as well as polarizability, for gases of known composition.

  19. Light Scattering at Various Angles

    PubMed Central

    Latimer, Paul; Pyle, B. E.

    1972-01-01

    The Mie theory of scattering is used to provide new information on how changes in particle volume, with no change in dry weight, should influence light scattering for various scattering angles and particle sizes. Many biological cells (e.g., algal cells, erythrocytes) and large subcellular structures (e.g., chloroplasts, mitochondria) in suspension undergo this type of reversible volume change, a change which is related to changes in the rates of cellular processes. A previous study examined the effects of such volume changes on total scattering. In this paper scattering at 10° is found to follow total scattering closely, but scattering at 45°, 90°, 135°, and 170° behaves differently. Small volume changes can cause very large observable changes in large angle scattering if the sample particles are uniform in size; however, the natural particle size heterogeneity of most samples would mask this effect. For heterogeneous samples of most particle size ranges, particle shrink-age is found to increase large angle scattering. PMID:4556610

  20. Rayleigh scattering correlation spectroscopy on diffusion dynamics of nanoparticles under intense laser irradiation

    NASA Astrophysics Data System (ADS)

    Hee, Ping-Yu; Uwada, Takayuki; Okano, Kazunori; Miura, Atsushi; Masuhara, Hiroshi

    2013-09-01

    Rayleigh scattering correlation microspectroscopy is developed and applied to study diffusion dynamics of some nanospheres in water. It was clearly found that the diffusion constant of gold nanoparticles decreased with increasing excitation laser power at the excitation wavelength of higher absorption cross section. This behavior was explained in terms of a coupling between laser trapping by the scattering excitation laser itself and laser heating of the particle. In the case of non-absorbing nanospheres such as silica and polystyrene, the excitation power dependence can be ascribed only to the laser trapping. Experimental setup is introduced, theoretical formulation is described, and future development of this measurement is considered.

  1. Standoff detection of large organic molecules using Rydberg fingerprint spectroscopy and microwave Rayleigh scattering

    SciTech Connect

    Rudakov, Fedor M; Zhang, Zhili

    2012-01-01

    We present a technique for nonintrusive and standoff detection of large organic molecules using coherent microwave Rayleigh scattering from plasma produced by structure sensitive photoionization through Rydberg states. We test the method on 1,4-diazobicyclooctane. Transitions between the 3s Rydberg state and higher lying Rydberg states are probed using two-color photoionization with 266?nm photons and photons in the range of 460-2400 nm. Photoionization is detected using microwave radiation, which is scattered by the unbounded electrons. Highly resolved Rydberg spectra are acquired in vacuum and in air.

  2. Temperature imaging in nonpremixed flames by joint filtered Rayleigh and Raman scattering.

    PubMed

    Kearney, Sean P; Schefer, Robert W; Beresh, Steven J; Grasser, Thomas W

    2005-03-20

    Joint fuel Raman and filtered Rayleigh-scattering (FRS) imaging is demonstrated in a laminar methane-air diffusion flame. These experiments are, to our knowledge, the first reported extension of the FRS technique to nonpremixed combustion. This joint imaging approach allows for correction of the FRS images for the large variations in Rayleigh cross section that occur in diffusion flames and for a secondary measurement of fuel mole fraction. The temperature-dependent filtered Rayleigh cross sections are computed with a six-moment kinetic model for calculation of major-species Rayleigh-Brillouin line shapes and a flamelet-based model for physically judicious estimates of gas-phase chemical composition. Shot-averaged temperatures, fuel mole fractions, and fuel number densities from steady and vortex-strained diffusion flames stabilized on a Wolfhard-Parker slot burner are presented, and a detailed uncertainty analysis reveals that the FRS-measured temperatures are accurate to within +/- 4.5 to 6% of the local absolute temperature. PMID:15813256

  3. Multiple light scattering methods for multiphase flow diagnostics

    NASA Astrophysics Data System (ADS)

    Estevadeordal, Jordi

    2015-11-01

    Multiphase flows of gases and liquids containing droplets, bubbles, or particulates present light scattering imaging challenges due to the interference from each phase, such as secondary reflections, extinctions, absorptions, and refractions. These factors often prevent the unambiguous detection of each phase and also produce undesired beam steering. The effects can be especially complex in presence of dense phases, multispecies flows, and high pressure environments. This investigation reports new methods for overcoming these effects for quantitative measurements of velocity, density, and temperature fields. The methods are based on light scattering techniques combining Mie and filtered Rayleigh scattering and light extinction analyses and measurements. The optical layout is designed to perform multiple property measurements with improved signal from each phase via laser spectral and polarization characterization, etalon decontamination, and use of multiple wavelengths and imaging detectors.

  4. Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

    NASA Astrophysics Data System (ADS)

    Zhou, Xiang; Liu, Qian; Han, Junbo; Zhang, Zhenyu; Zhang, Xuan; Ding, Yayun; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-11-01

    We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√{E{(MeV)}} required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments.

  5. Rayleigh scattering of two x-ray photons by an atom

    NASA Astrophysics Data System (ADS)

    Hopersky, Alexey N.; Nadolinsky, Alexey M.; Novikov, Sergey A.

    2016-05-01

    The process of elastic (Rayleigh) scattering of two x-ray free-electron laser (XFEL) photons by a free He atom is theoretically investigated. We obtain the absolute values and the forms of the triple differential scattering cross section. The main theoretical result is the highest probability of creation of scattered photons with energy ℏ ω±≅ℏ ω ±I1 s (ℏ ω is the energy of the incident XFEL photon, I1 s is the energy of the ionization threshold of the 1 s2 atomic shell). The probability of creation cooled (<ω- ) and hot (>ω+ ) photons is smaller by many orders of magnitude, and is identically zero when the formal (nonphysical) energy of one of the scattered photons is 2 ℏ ω .

  6. Novel technique for distributed fibre sensing based on coherent Rayleigh scattering measurements of birefringence

    NASA Astrophysics Data System (ADS)

    Lu, Xin; Soto, Marcelo A.; Thévenaz, Luc

    2016-05-01

    A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order of magnitude higher sensitivity than Brillouin sensing, and requiring access to a single fibre-end. Unlike the traditional Rayleigh-based coherent optical time-domain reflectometry, this new method provides absolute measurements of the measurand and may lead to a robust discrimination between temperature and strain in combination with another technique. Since birefringence is purposely induced in the fibre by design, large degrees of freedom are offered to optimize and scale the sensitivity to a given quantity. The technique has been validated in 2 radically different types of birefringent fibres - elliptical-core and Panda polarization-maintaining fibres - with a good repeatability.

  7. Temperature Deviations in the Midlatitude Mesosphere During Stratospheric Warmings as Measured with Rayleigh-Scatter Lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent; Fish, Chad; Herron, Joshua P.

    2016-06-01

    While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected an extensive set of temperature data for 11 years in the 45-90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the midlatitude mesospheric temperatures during these SSW events. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions during SSW events, and warmings in the lower mesosphere.

  8. Estimation of effective atomic number in the Rayleigh to Compton scattering ratio using different methods

    NASA Astrophysics Data System (ADS)

    Kurudirek, M.; Büyükyıldız, M.

    2016-06-01

    The Rayleigh to Compton scattering ratio (R/C) is a very convenient parameter, which can be utilized in material analysis and estimating effective atomic number (Zeff). In the case for a relatively low scattering angle, for which the energy of the Compton scattered photons is not very much different from that of incident photons, the corrections due to self-absorption for Rayleigh and Compton scattering will be roughly equal. Therefore, it enables a result to be obtained which is almost independent of X-ray attenuation inside the sample and it will depend only on the material under investigation. The most frequently used method for calculation of Zeff available in literature is plotting R/C of elements as a function of atomic number and constituting the best fit curve. From this fit curve, the respective Zeff can be determined using R/C of the material. In the present study, we report Zeff of different materials using different methods such as interpolation and direct methods as possible alternatives to the most common fitting method. The results were compared with the experiments wherever possible. The agreement between interpolation method and the fitting method was found to be very satisfactory as relative changes (%) were always less than 9% while the direct method results with somehow significantly higher values of Zeff when compared to the other methods.

  9. Generation of a super-Rayleigh speckle field via a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Li, Xinzhong; Tai, Yuping; Li, Hehe; Wang, Jingge; Wang, Hui; Nie, Zhaogang

    2016-04-01

    This study investigated the generation method and properties of a super-Rayleigh speckle field that had a contrast value greater than 1. First, an exponential factor was added to the complex amplitude of the Rayleigh speckle, and then, its inverse Fourier-transformed phase matrix was applied to a spatial light modulator (SLM). As the collimated light beam illuminated the SLM, the super-Rayleigh speckle field was formed at the SLM's Fourier plane. The effects of the exponential factor, size of the macro-pixel of the SLM, and diameter of the entrance pupil on the contrast values of the super-Rayleigh speckle patterns were investigated. Especially, the influence of different macro-pixel sizes of the SLM was systematically studied. Moreover, the stability region of the super-Rayleigh speckle field was examined. The experimental results showed that the contrast values of the super-Rayleigh speckle field increased exponentially as the exponential factor increased under the same conditions. In addition, the contrast values increased as the size of the macro-pixel or diameter of the entrance pupil increased. Furthermore, as the pupil diameter increased, the width of the stability region decreased according to a negative quadratic index that corresponded to the longitudinal length of a single speckle.

  10. Half a century of light scatter metrology and counting

    NASA Astrophysics Data System (ADS)

    Stover, John C.

    2014-09-01

    Back in the early days Bill Wolf once said something like: "The guy with the lowest scatter measurement is closest to the right answer." He was often right then - but not anymore. Everything has changed. Today measurements are limited by Rayleigh scatter from the air - not the instrument. We have both written and physical standards and everybody spells BRDF the same way. In the time it takes to give this talk, over 100,000 silicon wafers will be inspected around the world using a few thousand scatterometers - average price about one million dollars each. The way the world illuminates everything from homes to football fields is changing with the advent of high brightness LED's and these lighting systems are designed using a combination of scatter metrology and analysis techniques - many of which were started at The Optical Sciences Center. This paper reviews two major highlights in half a century of scatter metrology progress.

  11. Rayleigh scatter in kilovoltage x-ray imaging: is the independent atom approximation good enough?

    NASA Astrophysics Data System (ADS)

    Poludniowski, G.; Evans, P. M.; Webb, S.

    2009-11-01

    Monte Carlo simulation is the gold standard method for modelling scattering processes in medical x-ray imaging. General-purpose Monte Carlo codes, however, typically use the independent atom approximation (IAA). This is known to be inaccurate for Rayleigh scattering, for many materials, in the forward direction. This work addresses whether the IAA is sufficient for the typical modelling tasks in medical kilovoltage x-ray imaging. As a means of comparison, we incorporate a more realistic 'interference function' model into a custom-written Monte Carlo code. First, we conduct simulations of scatter from isolated voxels of soft tissue, adipose, cortical bone and spongiosa. Then, we simulate scatter profiles from a cylinder of water and from phantoms of a patient's head, thorax and pelvis, constructed from diagnostic-quality CT data sets. Lastly, we reconstruct CT numbers from simulated sets of projection images and investigate the quantitative effects of the approximation. We show that the IAA can produce errors of several per cent of the total scatter, across a projection image, for typical x-ray beams and patients. The errors in reconstructed CT number, however, for the phantoms simulated, were small (typically < 10 HU). The IAA can therefore be considered sufficient for the modelling of scatter correction in CT imaging. Where accurate quantitative estimates of scatter in individual projection images are required, however, the appropriate interference functions should be included.

  12. A systematic study of Rayleigh-Brillouin scattering in air, N₂, and O₂ gases.

    PubMed

    Gu, Ziyu; Ubachs, Wim

    2014-09-14

    Spontaneous Rayleigh-Brillouin scattering experiments in air, N2, and O2 have been performed for a wide range of temperatures and pressures at a wavelength of 403 nm and at a 90° scattering angle. Measurements of the Rayleigh-Brillouin spectral scattering profile were conducted at high signal-to-noise ratio for all three species, yielding high-quality spectra unambiguously showing the small differences between scattering in air, and its constituents N2 and O2. Comparison of the experimental spectra with calculations using the Tenti S6 model, developed in the 1970s based on linearized kinetic equations for molecular gases, demonstrates that this model is valid to high accuracy for N2 and O2, as well as for air. After previous measurements performed at 366 nm, the Tenti S6 model is here verified for a second wavelength of 403 nm, and for the pressure-temperature parameter space covered in the present study (250-340 K and 0.6-3 bars). In the application of the Tenti S6 model, based on the transport coefficients of the gases, such as thermal conductivity κ, internal specific heat capacity c(int) and shear viscosity η, as well as their temperature dependencies taken as inputs, values for the more elusive bulk viscosity η(b) for the gases are derived by optimizing the model to the measurements. It is verified that the bulk viscosity parameters obtained from previous experiments at 366 nm are valid for wavelengths of 403 nm. Also for air, which is treated as a single-component gas with effective gas transport coefficients, the Tenti S6 treatment is validated for 403 nm as for the previously used wavelength of 366 nm, yielding an accurate model description of the scattering profiles for a range of temperatures and pressures, including those of relevance for atmospheric studies. It is concluded that the Tenti S6 model, further verified in the present study, is applicable to LIDAR applications for exploring the wind velocity and the temperature profile distributions of

  13. A systematic study of Rayleigh-Brillouin scattering in air, N2, and O2 gases

    NASA Astrophysics Data System (ADS)

    Gu, Ziyu; Ubachs, Wim

    2014-09-01

    Spontaneous Rayleigh-Brillouin scattering experiments in air, N2, and O2 have been performed for a wide range of temperatures and pressures at a wavelength of 403 nm and at a 90° scattering angle. Measurements of the Rayleigh-Brillouin spectral scattering profile were conducted at high signal-to-noise ratio for all three species, yielding high-quality spectra unambiguously showing the small differences between scattering in air, and its constituents N2 and O2. Comparison of the experimental spectra with calculations using the Tenti S6 model, developed in the 1970s based on linearized kinetic equations for molecular gases, demonstrates that this model is valid to high accuracy for N2 and O2, as well as for air. After previous measurements performed at 366 nm, the Tenti S6 model is here verified for a second wavelength of 403 nm, and for the pressure-temperature parameter space covered in the present study (250-340 K and 0.6-3 bars). In the application of the Tenti S6 model, based on the transport coefficients of the gases, such as thermal conductivity κ, internal specific heat capacity cint and shear viscosity η, as well as their temperature dependencies taken as inputs, values for the more elusive bulk viscosity ηb for the gases are derived by optimizing the model to the measurements. It is verified that the bulk viscosity parameters obtained from previous experiments at 366 nm are valid for wavelengths of 403 nm. Also for air, which is treated as a single-component gas with effective gas transport coefficients, the Tenti S6 treatment is validated for 403 nm as for the previously used wavelength of 366 nm, yielding an accurate model description of the scattering profiles for a range of temperatures and pressures, including those of relevance for atmospheric studies. It is concluded that the Tenti S6 model, further verified in the present study, is applicable to LIDAR applications for exploring the wind velocity and the temperature profile distributions of the

  14. Correction of radiation absorption on biological samples using Rayleigh to Compton scattering ratio

    NASA Astrophysics Data System (ADS)

    Pereira, Marcelo O.; Conti, Claudio de Carvalho; dos Anjos, Marcelino J.; Lopes, Ricardo T.

    2012-06-01

    The aim of this work was to develop a method to correct the absorbed radiation (the mass attenuation coefficient curve) in low energy (E < 30 keV) applied to a biological matrix based on the Rayleigh to Compton scattering ratio and the effective atomic number. For calibration, scattering measurements were performed on standard samples of radiation produced by a gamma-ray source of 241Am (59.54 keV) also applied to certified biological samples of milk powder, hay powder and bovine liver (NIST 1557B). In addition, six methods of effective atomic number determination were used as described in literature to determinate the Rayleigh to Compton scattering ratio (R/C), in order to calculate the mass attenuation coefficient. The results obtained by the proposed method were compared with those obtained using the transmission method. The experimental results were in good agreement with transmission values suggesting that the method to correct radiation absorption presented in this paper is adequate for biological samples.

  15. Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation

    NASA Astrophysics Data System (ADS)

    El-Taher, A. E.; Harper, P.; Babin, S. A.; Churkin, D. V.; Podivilov, E. V.; Ania-Castanon, J. D.; Turitsyn, S. K.

    2011-02-01

    We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating (FBG) reflectors and distributed feedback via Rayleigh scattering in a ~22 km long optical fiber. Twenty two lasing lines with spacing of ~100 GHz (close to ITU grid) in C-band are generated at Watts power level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution which is almost independent on power. The current set up showing the capability of generating Raman gain of about 100-nm wide giving the possibility of multiwavelength generation at different bands.

  16. Strain Engineering of the Band Structure and Picosecond Carrier Dynamics of Single Semiconductor Nanowires Probed by Modulated Rayleigh Scattering Microscopy

    NASA Astrophysics Data System (ADS)

    Montazeri, Mohammad

    The band structure and carrier dynamics of GaAs, GaAs/GaP and InP semiconductor nanowires is explored using a variety of optical spectroscopy techniques including two newly developed techniques called Photomodulated and Transient Rayleigh scattering spectroscopy. The stress and electronic band structure of as-grown highly strained GaAs/GaP core/shell nanowire is studied via room temperature Raman scattering by phonons and low temperature photoluminescence spectroscopy. Raman measurements reveal the uniaxial nature of the shell-induced stress in the core GaAs nanowire with a significantly different degree of compression in the radial plane and axial direction of the nanowire. The uniaxial stress dramatically modifies the electronic band structure of the nanowire. Raman measurements predict that the shell-induced stress should shift the band gap of GaAs to higher energies by ~260 meV which is experimentally confirmed by low temperature photoluminescence spectroscopy. Furthermore, it is predicted that the uniaxial stress in the nanowire removes the degeneracy of the heavy and light hole valence bands at the zone center by ~100 meV. In order to probe the electronic band structure of single nanowires with high spatial and spectral resolution, the new technique of Photomodulated Rayleigh Scattering spectroscopy (PMRS) is introduced. We show that by photomodulating the dielectric function of the nanowire, the background-free and robust differential Rayleigh spectrum measures the band structure of the nanowire with exceptionally high energy resolution. PMRS measurements are performed on zincblende GaAs and zincblende and wurtzite InP nanowires at both room and low temperature. Furthermore, we show that the diameters of the nanowires can be extracted from the PMRS spectra with an uncertainty of only a few nanometers. By extending the PMRS spectroscopy into time domain, we introduce Transient Rayleigh Scattering spectroscopy (TRS) to study the ultrafast carrier dynamics and

  17. A Dual-Line Detection Rayleigh Scattering Diagnostic Technique for the Combustion of Hydrocarbon Fuels and Filtered UV Rayleigh Scattering for Gas Velocity Measurements

    NASA Technical Reports Server (NTRS)

    Otugen, M. Volkan

    1997-01-01

    Non-intrusive techniques for the dynamic measurement of gas flow properties such as density, temperature and velocity, are needed in the research leading to the development of new generation high-speed aircraft. Accurate velocity, temperature and density data obtained in ground testing and in-flight measurements can help understand the flow physics leading to transition and turbulence in supersonic, high-altitude flight. Such non-intrusive measurement techniques can also be used to study combustion processes of hydrocarbon fuels in aircraft engines. Reliable, time and space resolved temperature measurements in various combustor configurations can lead to a better understanding of high temperature chemical reaction dynamics thus leading to improved modeling and better prediction of such flows. In view of this, a research program was initiated at Polytechnic University's Aerodynamics Laboratory with support from NASA Lewis Research Center through grants NAG3-1301 and NAG3-1690. The overall objective of this program has been to develop laser-based, non-contact, space- and time-resolved temperature and velocity measurement techniques. In the initial phase of the program a ND:YAG laser-based dual-line Rayleigh scattering technique was developed and tested for the accurate measurement of gas temperature in the presence of background laser glare. Effort was next directed towards the development of a filtered, spectrally-resolved Rayleigh/Mie scattering technique with the objective of developing an interferometric method for time-frozen velocity measurements in high-speed flows utilizing the uv line of an ND:YAG laser and an appropriate molecular absorption filter. This effort included both a search for an appropriate filter material for the 266 nm laser line and the development and testing of several image processing techniques for the fast processing of Fabry-Perot images for velocity and temperature information. Finally, work was also carried out for the development of

  18. Light Scattering by Nonspherical Particles

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael I.; Travis, Larry D.; Hovenier, Joop W.

    1998-01-01

    Improved understanding of electromagnetic scattering by nonspherical particles is important to many science and engineering disciplines and was the subject of the Conference on Light Scattering by Nonspherical Particles: Theory, Measurements, and Applications. The conference was held 29 September-1 October 1998 at the Goddard Institute for Space Studies in New York City and brought together 115 participants from 18 countries. The main objective of the conference was to highlight and summarize the rapid advancements in the field, including numerical methods for computing the single and multiple scattering of electromagnetic radiation by nonspherical and heterogeneous particles, measurement approaches, knowledge of characteristic features in scattering patterns, retrieval and remote sensing techniques, nonspherical particle sizing, and various practical applications. The conference consisted of twelve oral and one poster sessions. The presentations were loosely grouped based on broad topical categories. In each of these categories invited review talks highlighted and summarized specific active areas of research. To ensure a high-quality conference, all abstracts submitted had been reviewed by members of the Scientific Organizing Committee for technical merit and content. The conference program was published in the June 1998 issue of the Bulletin of the American Meteorological Society and is available on the World Wide Web at http://www.giss.nasa.gov/-crmim/conference/program.html. Authors of accepted papers and review presentations contributed to a volume of preprints published by the American Meteorological Society' and distributed to participants at the conference.

  19. Long-range orientation correlation in dipolar liquids probed by hyper-Rayleigh scattering.

    PubMed

    Shelton, David P

    2015-10-01

    Hyper-Rayleigh scattering (HRS) is sensitive to long-range molecular orientation correlation in isotropic liquids composed of dipolar molecules. The correlation functions that appear in the calculation of HRS mediated by the vector part of the first hyperpolarizability β are the same as the correlation functions for the homogeneous isotropic random vector fields that appear in the description of fluid turbulence. Recent experiments measuring the angle and polarization dependence of HRS from water find a dominant transverse mode contribution with amplitude independent of the scattering wavevector, and this observation of transverse mode HRS strongly constrains the form of the orientation correlation function. Analysis of these HRS results for water determines that the long-range molecular orientation correlation function varies as r(-3±ε) with |ε| < 0.03 on spatial scales up to 2000 nm. PMID:26450319

  20. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    SciTech Connect

    Nedanovska, E.; Nersisyan, G.; Lewis, C. L. S.; Riley, D.; Graham, W. G.; Morgan, T. J.; Hüwel, L.; Murakami, T.

    2015-01-07

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 10{sup 17 }cm{sup −3} to 9 × 10{sup 13 }cm{sup −3}, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ∼ t{sup 0.4} consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He{sub 2}{sup +} molecular ion play an important role.

  1. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    NASA Astrophysics Data System (ADS)

    Nedanovska, E.; Nersisyan, G.; Morgan, T. J.; Hüwel, L.; Murakami, T.; Lewis, C. L. S.; Riley, D.; Graham, W. G.

    2015-01-01

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 1017 cm-3 to 9 × 1013 cm-3, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ˜ t0.4 consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He2+ molecular ion play an important role.

  2. Demonstration of Imaging Flow Diagnostics Using Rayleigh Scattering in Langley 0.3-Meter Transonic Cryogenic Tunnel

    NASA Technical Reports Server (NTRS)

    Shirinzadeh, B.; Herring, G. C.; Barros, Toya

    1999-01-01

    The feasibility of using the Rayleigh scattering technique for molecular density imaging of the free-stream flow field in the Langley 0.3-Meter Transonic Cryogenic Tunnel has been experimentally demonstrated. The Rayleigh scattering was viewed with a near-backward geometry with a frequency-doubled output from a diode-pumped CW Nd:YAG laser and an intensified charge-coupled device camera. Measurements performed in the range of free-stream densities from 3 x 10(exp 25) to 24 x 10(exp 25) molecules/cu m indicate that the observed relative Rayleigh signal levels are approximately linear with flow field density. The absolute signal levels agree (within approx. 30 percent) with the expected signal levels computed based on the well-known quantities of flow field density, Rayleigh scattering cross section for N2, solid angle of collection, transmission of the optics, and the independently calibrated camera sensitivity. These results show that the flow field in this facility is primarily molecular (i.e., not contaminated by clusters) and that Rayleigh scattering is a viable technique for quantitative nonintrusive diagnostics in this facility.

  3. Rayleigh-Scattering-Induced Noise in Analog RF-Photonic Links

    NASA Astrophysics Data System (ADS)

    Cahill, James P.

    Analog RF-photonic links hold the potential to increase the precision of time and frequency synchronization in commercial applications by orders of magnitude. However, current RF-photonic links that are used for synchronization must suppress optical-fiber-induced noise by using bi-directional active feedback schemes, in which light must travel through the optical fiber in both directions. These schemes are incompatible with most existing fiber-optic networks. Unless this noise can be suppressed using different methods, RF-photonic time and frequency synchronization will remain accessible only to the research community. As a first step towards identifying alternate means of suppressing the optical-fiber-induced noise, this dissertation presents an extensive experimental characterization and limited theoretical discussion of the dominant optical-intensity and RF-phase noise source in a laboratory setting, where environmental fluctuations are small. The experimental results indicate that the optical-fiber-induced RF-phase noise and optical-intensity noise are caused by the same physical mechanism. The experimental results demonstrate that this mechanism is related to the laser-phase noise but not the laser intensity noise. The bandwidth of the optical-fiber-induced noise depends on the optical-fiber length for lasers with low phase noise, while for lasers with high phase noise, the bandwidth is constant. I demonstrate that the optical-intensity and RF-phase noise can be mitigated by dithering the laser frequency. Based on these results, I hypothesize that interference from Rayleigh scattering is the underlying mechanism of the optical-intensity and RF-phase noise. Prior theoretical work, carried out with high phase noise lasers, predicts that the noise induced by this process will have a bandwidth that is proportional to the laser linewidth and that is constant with respect to the optical-fiber length, for lasers with high-phase noise, which is consistent with the

  4. Measuring the scattering mean free path of Rayleigh waves on a volcano from spatial phase decoherence

    NASA Astrophysics Data System (ADS)

    Obermann, Anne; Larose, Eric; Margerin, Ludovic; Rossetto, Vincent

    2014-05-01

    We analyze the statistics of phase fluctuations of seismic signals obtained from a temporary small aperture array deployed on a volcano in the French Auvergne. We demonstrate that the phase field satisfies Circular Gaussian statistics. We then determine the scattering mean free path of Rayleigh waves from the spatial phase decoherence. This phenomenon, observed for diffuse wavefields, is found to yield a good approximation of the scattering mean free path. Contrary to the amplitude, spatial phase decoherence is free from absorption effects and provides direct access to the scattering mean free path. Our method may find applications in various areas of seismology where the effects of scattering are prominent and a knowledge of the scattering properties is necessary to describe the propagation. As an example, an unbiased estimate of the scattering mean free path is crucial for the localization of changes in multiply scattering media, where a sensitivity kernel based on diffusion theory is used (Larose et al. 2010; Obermann et al. 2013a,b). Our experimental approach may also provide independent estimates of the scattering mean free path in volcanic areas where particularly strong scattering has been proposed, based on the fitting of energy envelopes using energy transport approaches (Wegler & Lühr 2001; Yamamoto & Sato 2010). References: Larose, E., Planès, T., Rossetto, V. & Margerin, L., 2010. Locating a small change in a multiple scattering environment, Appl. Phys. Lett., 96(204101), 1-3. Obermann, A., Planès, T., Larose, E. & Campillo, M., 2013a. Imaging pre and co-eruptive structural and mechanical changes on a volcano with ambient seismic noise, J. geophys. Res., 118, 1-10. Obermann, A., Planès, T., Larose, E., Sens-Schönfelder, C. & Campillo,M., 2013b. Depth sensitivity of seismic coda waves to velocity perturbations in an elastic heterogeneous medium, Geophys. J. Int., 194(1), 372-382. Wegler, U. & Lühr, B.G., 2001. Scattering behaviour at Merapi volcano

  5. What is the contribution of scattering to the Love-to-Rayleigh ratio in ambient microseismic noise?

    NASA Astrophysics Data System (ADS)

    Ziane, D.; Hadziioannou, C.

    2015-12-01

    Several observations show the existence of both Rayleigh and Love waves in the secondary microseism. While the Rayleigh wave excitation is well described by Longuet-Higgins, the process responsible for Love wave generation still needs further investigation. Several different mechanisms could excite Love waves in this frequency band: broadly speaking, we can differentiate between source effects, like pressure variations on the oblique sea floor, or internal effects in the medium along the propagation path, such as scattering and conversions. Here we will focus on the internal effects. We perform single scattering tests in 2D and 3D to gain a better understanding of the scattering radiation pattern and the conversion between P, S, Rayleigh and Love waves. Furthermore, we use random media with continuous variations of the elastic parameters to create a scattering regime similar to the Earths interior, e.g. Gaussian or von Karmann correlation functions. The aim is to explore the contribution of scattering along the propagation path to the observed Love to Rayleigh wave energy ratios, assuming a purely vertical force source mechanism. We use finite different solvers to calculate the synthetic seismograms, and to separate the different wave types we measure the rotational and divergent components of the wave field.

  6. Enhancement of Rayleigh scatter in optical fiber by simple UV treatment: an order of magnitude increase in distributed sensing sensitivity

    NASA Astrophysics Data System (ADS)

    Loranger, Sébastien; Parent, François; Lambin-Iezzi, Victor; Kashyap, Raman

    2016-02-01

    Rayleigh scatter in optical fiber communication systems has long been considered a nuisance as a loss mechanism, although applications have used such scatter to probe the fiber for faults and propagation loss using time domain reflectometry (OTDR). It is however only with the development of Frequency domain reflectometry (OFDR) and coherent-phase OTDR that Rayleigh scatter has been probed to its deepest and can now be used to measure strain and temperature along a fiber, leading to the first distributed sensing applications. However, Rayleigh scatter remains very weak giving rise to very small signals which limits the technique for sensing. We show here a new technique to significantly enhance the Rayleigh scatter signal by at least two orders of magnitude, in a standard optical fiber with simple UV exposure of the core. A study of various exposures with different types of fibers has been conducted and a phenomenological description developed. We demonstrate that such an increase in signal can enhance the temperature and strain sensitivity by an order of magnitude for distributed sensing with an OFDR technique. Such improved performance can lead to temperature/strain RMS noise levels of 6 mK and 50 nɛ for 1 cm spatial resolution in UV exposed SMF-28, compared to the typical noise level of 100 mK for the same spatial resolution in the similar unexposed fiber.

  7. Effect of molecular anisotropy on the intensity and degree of polarization of light scattered from model atmospheres

    NASA Technical Reports Server (NTRS)

    Bahethi, O. P.; Fraser, R. S.

    1980-01-01

    Computations of the properties of sunlight scattered from models of the earth-atmosphere system are presented to show the effect of molecular anisotropy on the intensity, flux, and degree of polarization of the scattered light. The values of these parameters change significantly when the anisotropy factor is neglected in the molecular optical thickness and scattering phase matrix. However, if the Rayleigh scattering optical thickness is kept constant and the molecular anisotropy factor is included only in the Rayleigh phase matrix, the flux does not change, the intensity changes by a small amount, but the changes in the degree of polarization are still significant.

  8. Light scattering by a thin wire with a surface-plasmon resonance: Bifurcations of the Poynting vector field

    SciTech Connect

    Luk'yanchuk, B. S.; Ternovsky, V.

    2006-06-15

    We analyze the energy flow during the scattering of a plane wave by a small homogeneous cylinder in the vicinity of surface-plasmon resonance, where {epsilon}{sup '}=Re {epsilon}=-1 ({epsilon} stands for permittivity). For the case of small dissipation, {epsilon}{sup ''}=Im {epsilon}<<1, this scattering can strongly deviate from the classical dipole approximation (Rayleigh scattering). In certain specified cases, the Rayleigh scattering is replaced with an anomalous light scattering regardless the wire smallness. The phenomenon is based on interplay of the usual dissipative and radiative damping, where the latter is related to inverse transformation of localized resonant plasmons into scattered light. The anomalous light scattering possesses a variety of unusual features, such as an inverse hierarchy of optical resonances and a complicated near-field structure, which may include optical vortexes, optical whirlpools, and other peculiarities in nanoscale area.

  9. Development of a Rayleigh Scattering Diagnostic for Time-Resolved Gas Flow Velocity, Temperature, and Density Measurements in Aerodynamic Test Facilities

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen

    2007-01-01

    A molecular Rayleigh scattering technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded turbulent flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultiplier tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. An acoustically driven nozzle flow is studied to validate velocity fluctuation measurements, and an asymmetric oscillating counterflow with unequal enthalpies is studied to validate the measurement of temperature fluctuations. Velocity fluctuations are compared with constant temperature anemometry measurements and temperature fluctuations are compared with constant current anemometry measurements at the same locations. Time-series and power spectra of the temperature and velocity measurements are presented. A numerical simulation of the light scattering and detection process was developed and compared with experimental data for future use as an experiment design tool.

  10. Wavelength dependence of the hyper Rayleigh scattering response from gold nanoparticles.

    PubMed

    Russier-Antoine, Isabelle; Jonin, Christian; Nappa, Jérôme; Bénichou, Emmanuel; Brevet, Pierre-François

    2004-06-01

    The wavelength dependence of the quadratic hyperpolarizability of 11 nm diam gold nanoparticles, is reported as measured by hyper Rayleigh scattering. An important photoluminescence background underlying the hyper Rayleigh signal is observed, a contribution attributed to radiative electron-hole recombinations following multiphoton excitation favored by adsorbed organic compound like citrate on the surface of the nanoparticles. The absolute value of the quadratic hyperpolarizability of gold spherical nanoparticles is determined and a strong enhancement is observed for harmonic frequencies in resonance with the dipolar surface plasmon excitation. No contribution of the interband transition is observed. The absolute values reported, beta(C)=5.1x10(-26) esu at the second harmonic energy 2.39 eV, have been measured with femtosecond long laser pulse, and are 1 order of magnitude weaker that the one previously reported with nanosecond long pulses. This difference can be related to similar measurements performed on the second order hyperpolarizability of gold nanoparticles and may be attributed to different electronic relaxation regimes. Finally, the spectrum of the quadratic hyperpolarizability is compared to the theoretically expected one. PMID:15268100

  11. Connection between the midlatitude mesosphere and sudden stratospheric warmings as measured by Rayleigh-scatter lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent B.; Fish, Chad S.; Herron, Joshua P.

    2016-05-01

    While the mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are much more sparse. The Rayleigh-scatter lidar system, which operated at the Center for Atmospheric and Space Sciences on the campus of Utah State University (41.7°N, 111.8°W), collected a very dense set of observations, from 1993 to 2004, over a 45-90 km altitude range. This paper focuses on Rayleigh lidar temperatures derived during the six major SSW events that occurred during the 11 year period when the lidar was operating and aims to characterize the local response to these midlatitude SSW events. In order to determine the characteristics of these mesospheric temperature anomalies, comparisons were made between the temperatures from individual nights during a SSW event and a climatological temperature profile. An overall disturbance pattern was observed in the mesospheric temperatures associated with SSW events, including coolings in the upper mesosphere and warmings in the upper stratosphere and lower mesosphere, both comparable to those seen at polar latitudes.

  12. Slow-light effect via Rayleigh anomaly and the effect of finite gratings

    PubMed Central

    Kim, Kyoung-Youm; Chong, Xinyuan; Ren, Fanghui; Wang, Alan X.

    2016-01-01

    In this Letter, we investigate the slow-light effect of sub-wavelength diffraction gratings via the Rayleigh anomaly using a fully analytical approach without needing to consider specific grating structures. Our results show that the local group velocity of the transmitted light can be significantly reduced due to the optical vortex, which can inspire a new mechanism to enhance light–matter interactions for optical sensing and photodetection. However, the slow-light effect will diminish as the transmitted light propagates farther from the grating surface, and the slowdown factor decreases as the grating size shrinks. PMID:26565869

  13. Dynamic light scattering homodyne probe

    NASA Technical Reports Server (NTRS)

    Meyer, William V. (Inventor); Cannell, David S. (Inventor); Smart, Anthony E. (Inventor)

    2002-01-01

    An optical probe for analyzing a sample illuminated by a laser includes an input optical fiber operably connectable to the laser where the input optical fiber has an entrance end and an exit end. The probe also includes a first beam splitter where the first beam splitter is adapted to transmit an alignment portion of a light beam from the input fiber exit end and to reflect a homodyning portion of the light beam from the input fiber. The probe also includes a lens between the input fiber exit end and the first beam splitter and a first and a second output optical fiber, each having an entrance end and an exit end, each exit end being operably connectable to respective optical detectors. The probe also includes a second beam splitter which is adapted to reflect at least a portion of the reflected homodyning portion into the output fiber entrance ends and to transmit light from the laser scattered by the sample into the entrance ends.

  14. Scattering of guided light by a single hole in a dielectric slab.

    PubMed

    Mariani, F; van Exter, M P

    2015-06-29

    We study the scattering of waveguided light by a single hole in a dielectric slab with FDTD simulations and investigate two scattering processes: two dimensional (2D) scattering into slab modes and three-dimensional (3D) scattering into the surroundings. We find that 2D scattering typically dominates over the 3D losses. We find important quantitative differences between the single hole scattering and the case of scattering from an infinite Mie cylinder. Additionally, we find that a hole cannot be simply modelled as a dipolar object even in the limit of small scatterers (Rayleigh approximation). This is visible from the angular dependence of the 2D scattered intensity. We discuss the relevance of our findings in the modeling of two dimensional random scattering media. PMID:26191761

  15. Strong hyper-Rayleigh scattering from silver nanoparticle aggregates to be used for the optical bio-sensing assay

    NASA Astrophysics Data System (ADS)

    Kim, Joon Heon; Park, Jung Su; Kim, Min-Gon

    2013-05-01

    Hyper-Rayleigh Scattering (HRS) is a second-order nonlinear optical process in which the scattered light can be detected at the second harmonic wavelength of the input laser beam. Due to its incoherent nature, it can be observed from metal nanoparticles whose size is much smaller than the wavelength. Its sensitive response to the nanoparticle aggregation can be used as a powerful diagnostic tool for the detection of biological target molecules. Many previous bio-sensing applications of HRS have used gold nanoparticles as their sensing platform due to easy synthesis and functionalization of them. Here, we demonstrate that the aggregation of silver nanoparticles induced by poly-L-lysine molecules can generate much higher HRS than that from gold nanoparticle aggregates when using a Ti:Sapphire femtosecond laser. In spite of several drawbacks of silver nanoparticle system regarding the nonlinear response to target concentration and the difficulty of surface functionalization compared to the gold nanoparticle system, much higher HRS from silver nanoparticles can be definitely useful for the sensitive detection of very small amount of target molecules.

  16. Applications of Rayleigh scattering to turbulent flows with heat transfer and combustion

    NASA Astrophysics Data System (ADS)

    Talbot, L.; Robben, F.

    1982-05-01

    Rayleigh scattering has been developed as a diagnostic tool and used in conjunction with Laser Doppler velocimetry to study two reacting flows; the interaction of a Karman vortex street with a flame, and the interaction of grid-produced turbulence with a flame. Vortex street interaction is characterized by radical distortion of the flame front. Dilatation effects downstream of the flame front dominate, and vortices are not discernible in this region. Numerical modeling gave qualitative agreement with the experimental results. For the grid-induced turbulence, the measured density and velocity statistics were compared with the predictions of the Bray-Moss-Libby model. It was found that intermediate states had to be taken into account. Two-point density correlation measurements, the first ever reported, showed that the length scales of turbulence within the reaction zone were the same in all three orthogonal directions. Space-time correlation measurements in the flow direction were in accord with the Taylor hypothesis.

  17. A new resonance Rayleigh scattering spectral method for determination of O3 with victoria blue B

    NASA Astrophysics Data System (ADS)

    Wen, Guiqing; Yang, Duo; Jiang, Zhiliang

    2014-01-01

    Ozone (O3) could be absorbed by boric acid-potassium iodide (BKI) absorbent solution to produce tri-iodine ion (I3-) that react with victoria blue B (VBB) to form the associated particle (VBB-I3)n and exhibited a strong resonance Rayleigh scattering (RRS) peak at 722 nm. Under the chosen conditions, the RRS peak intensity was linear with O3 concentration in the range of 0.2-50 μmol/L, with a linear regression equation of ΔI722 = 17.9c - 45.4 and detection limit of 0.057 μmol/L. Accordingly, a simple, rapid and sensitive RRS spectral method was set up for determination of trace O3 in air, with satisfactory results.

  18. Study of thermal transport in nanoparticle suspensions using forced Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Venerus, David C.; Kabadi, Madhu S.; Lee, Sunmook; Perez-Luna, Victor

    2006-11-01

    Thermal diffusivity measurements on two nanofluids and their base fluids were made using an optical technique called forced Rayleigh scattering. The nanofluids studied were a citrate-stabilized Au nanoparticle suspension in water and an Al2O3 nanoparticle suspension in a petroleum oil. Thermal diffusivity measurements on the nanofluids and base fluids were made at temperatures in the range of 25-75°C. From these data, it was possible to estimate the thermal conductivity enhancement in the nanofluids as a function of temperature. In contrast to previous reports on similar systems, our experiments are consistent with thermal conductivity enhancement predictions from effective medium theory. In particular, we find that the level of thermal conductivity enhancement is independent of temperature.

  19. Broadband flat-amplitude multiwavelength Brillouin-Raman fiber laser with spectral reshaping by Rayleigh scattering.

    PubMed

    Wang, Zinan; Wu, Han; Fan, Mengqiu; Li, Yi; Gong, Yuan; Rao, Yunjiang

    2013-12-01

    In this letter, we propose a novel configuration for generating multiwavelength Brillouin-Raman fiber laser (MBRFL). The spectral reshaping effect introduced by Rayleigh scattering in a 50 km single mode fiber unifies the generated Brillouin comb in terms of both power level and linewidth. As a consequence, we are able to obtain a 40 nm flat-amplitude MBRFL with wide bandwidth from 1557 nm to 1597 nm covering >500 Stokes lines. This is, to the best of our knowledge, the widest flat-amplitude bandwidth of MBRFL with uniform Stokes combs using just a single Raman pump laser. The channel-spacing is 0.08 nm and the measured OSNR is higher than 12.5 dB. We also demonstrate that the output spectrum of the MBRFL is nearly unaffected over 14 dB range of Brillouin pumping power. PMID:24514489

  20. Highly sensitive detection of chromium (III) ions by resonance Rayleigh scattering enhanced by gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Min; Cai, Huai-Hong; Yang, Fen; Lin, Dewen; Yang, Pei-Hui; Cai, Jiye

    2014-01-01

    Simple and sensitive determination of chromium (III) ions (Cr3+) has potential applications for detecting trace contamination in environment. Here, the assay is based on the enhancement of resonance Rayleigh scattering (RRS) by Cr3+-induced aggregation of citrate-capped gold nanoparticles (AuNPs). Transmission electron microscopy (TEM) and UV-vis absorption spectroscopy were employed to characterize the nanostructures and spectroscopic properties of the Cr3+-AuNP system. The experiment conditions, such as reaction time, pH value, salt concentration and interfering ions, were investigated. The combination of signal amplification of Cr3+-citrate chelation with high sensitivity of RRS technique allow a selective assay of Cr3+ ions with a detection limit of up to 1.0 pM. The overall assay can be carried out at room temperature within only twenty minutes, making it suitable for high-throughput routine applications in environment and food samples.

  1. Molecular Rayleigh Scattering Techniques Developed for Measuring Gas Flow Velocity, Density, Temperature, and Turbulence

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Kristie A.; Panda, Jayanta

    2005-01-01

    Nonintrusive optical point-wise measurement techniques utilizing the principles of molecular Rayleigh scattering have been developed at the NASA Glenn Research Center to obtain time-averaged information about gas velocity, density, temperature, and turbulence, or dynamic information about gas velocity and density in unseeded flows. These techniques enable measurements that are necessary for validating computational fluid dynamics (CFD) and computational aeroacoustic (CAA) codes. Dynamic measurements allow the calculation of power spectra for the various flow properties. This type of information is currently being used in jet noise studies, correlating sound pressure fluctuations with velocity and density fluctuations to determine noise sources in jets. These nonintrusive techniques are particularly useful in supersonic flows, where seeding the flow with particles is not an option, and where the environment is too harsh for hot-wire measurements.

  2. Rayleigh to Compton ratio scatter tomography applied to breast cancer diagnosis: A preliminary computational study

    NASA Astrophysics Data System (ADS)

    Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.

    2014-02-01

    In the present work, a tomographic technique based on Rayleigh to Compton scattering ratio (R/C) was studied using computational simulation in order to assess its application to breast cancer diagnosis. In this preliminary study, some parameters that affect the image quality were evaluated, such as: (i) energy beam, (ii) size and glandularity of the breast, and (iii) statistical count noise. The results showed that the R/C contrast increases with increasing photon energy and decreases with increasing glandularity of the sample. The statistical noise showed to be a significant parameter, although the quality of the obtained images was acceptable for a considerable range of noise level. The preliminary results suggest that the R/C tomographic technique has a potential of being applied as a complementary tool in the breast cancer diagnostic.

  3. Highly sensitive detection of melamine based on gemini surfactant using enhanced resonance Rayleigh scattering signals

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Dong, Jiang Xue; Li, Nian Bing; Luo, Hong Qun

    2013-02-01

    We present here a resonance Rayleigh scattering (RRS) spectrum method for the determination of melamine at the nanogram level using a gemini surfactant (disodium 4-dodecyl-2,4'-oxydibenzenesulfonate, DDOF). It was found that DDOF could react with cationic melamine to form an ion-association complex, which induced the enhancement of RRS intensity and the appearance of a new RRS spectrum in acetate buffer (pH 3.6). The RRS spectral characteristics of the melamine-DDOF system, the optimum conditions of the reaction, and the influencing factors have been investigated. Under optimum conditions, the enhanced RRS intensity was proportional to the concentration of melamine in the range of 0.38-6.30 μg/mL. The method has high sensitivity, and the detection limit for melamine is 8.48 ng/mL. Furthermore, the reaction mechanism and the reasons of RRS enhancement were evaluated.

  4. Light scattering of degenerate fermions

    NASA Astrophysics Data System (ADS)

    Aubin, S.; Leblanc, L. J.; Myrskog, S.; Extavour, M. H. T.; McKay, D.; Stummer, A.; Thywissen, J. H.

    2006-05-01

    We report on progress in measuring the suppression of resonant light scattering in a gas of degenerate fermions. A gas of trapped degenerate fermions is expected to exhibit narrower optical linewidths and longer excited state lifetimes than single atoms when the Fermi energy is larger than the photon recoil energy [1-3]. In this case, the number of available states into which a scattered atom can recoil is significantly reduced due to the filling of the Fermi sea. We produce a degenerate gas of 4x10^4 ultra-cold fermionic ^40K atoms by sympathetic cooling with bosonic ^87Rb in a micro-magnetic chip trap. The atoms can then be loaded into a tight dipole trap just above the surface of the chip and probed with a near resonance laser pulse. [1] Th. Busch, J. R. Anglin, J. I. Cirac, and P. Zoller, Europhys. Lett. 44, 1 (1998). [2] B. DeMarco and D. S. Jin, Phys. Rev. A 58, R4267 (1998). [3] J. Javanainen and J. Ruostekosky, Phys. Rev. A 52, 3033 (1995). Work supported by NSERC, CFI, OIT, Research Corporation, and PRO.

  5. Biological cell classification by multiangle light scattering

    DOEpatents

    Salzman, G.C.; Crowell, J.M.; Mullaney, P.F.

    1975-06-03

    The specification is directed to an apparatus and method for detecting light scattering from a biological cell. Light, preferably from a coherent source of radiation, intercepts an individual biological cell in a stream of cells passing through the beam. Light scattered from the cell is detected at a selected number of angles between 0 and 90/sup 0/ to the longitudinal axis of the beam with a circular array of light responsive elements which produce signals representative of the intensity of light incident thereon. Signals from the elements are processed to determine the light-scattering pattern of the cell and therefrom its identity.

  6. Light scattering from dislocations in silicon

    NASA Astrophysics Data System (ADS)

    Monier, Vanessa; Capello, Luciana; Kononchuk, Oleg; Pichaud, Bernard

    2010-11-01

    Nondecorated glide dislocations in Czochralski grown silicon have been studied by laser scattering tomography technique. Dependence of intensity of scattered light on polarization of the incident light has been measured for different orientations of the dislocation line and Burgers vector. Detailed theory of light scattering by dislocation in silicon crystals is presented. It is shown that by combination of polarization and tomography measurements it is possible to determine slip system of nondecorated mixed dislocation in Si.

  7. Rayleigh Light Scattering for Concentration Measurements in Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Pitts, William M.

    1996-01-01

    Despite intensive research over a number of years, an understanding of scalar mixing in turbulent flows remains elusive. An understanding is required because turbulent mixing has a pivotal role in a wide variety of natural and technologically important processes. As an example, the mixing and transport of pollutants in the atmosphere and in bodies of water are often dependent on turbulent mixing processes. Turbulent mixing is also central to turbulent combustion which underlies most hydrocarbon energy use in modern societies as well as in unwanted fire behavior. Development of models for combusting flows is therefore crucial, however, an understanding of scalar mixing is required before useful models of turbulent mixing and, ultimately, turbulent combustion can be developed. An important subset of turbulent flows is axisymmetric turbulent jets and plumes because they are relatively simple to generate, and because the provide an appropriate test bed for the development of general theories of turbulent mixing which can be applied to more complex geometries and flows. This paper focuses on a number of experimental techniques which have been developed at the National Institute of Standards and Development for measuring concentration in binary axisymmetric turbulent jets. In order to demonstrate the value of these diagnostics, some of the more important results from earlier and on-going investigations are summarized. Topics addressed include the similarity behavior of variable density axisymmetric jets, the behavior of absolutely unstable axisymmetric helium jets, and the role of large scale structures and scalar dissipation in these flows.

  8. Brillouin light scattering from surface acoustic waves in a subwavelength-diameter optical fibre.

    PubMed

    Beugnot, Jean-Charles; Lebrun, Sylvie; Pauliat, Gilles; Maillotte, Hervé; Laude, Vincent; Sylvestre, Thibaut

    2014-01-01

    Brillouin scattering in optical fibres is a fundamental interaction between light and sound with important implications ranging from optical sensors to slow and fast light. In usual optical fibres, light both excites and feels shear and longitudinal bulk elastic waves, giving rise to forward-guided acoustic wave Brillouin scattering and backward-stimulated Brillouin scattering. In a subwavelength-diameter optical fibre, the situation changes dramatically, as we here report with the first experimental observation of Brillouin light scattering from surface acoustic waves. These Rayleigh-type surface waves travel the wire surface at a specific velocity of 3,400 m s(-1) and backscatter the light with a Doppler shift of about 6 GHz. As these acoustic resonances are sensitive to surface defects or features, surface acoustic wave Brillouin scattering opens new opportunities for various sensing applications, but also in other domains such as microwave photonics and nonlinear plasmonics. PMID:25341638

  9. Light scattering by randomly oriented spheroidal particles

    NASA Technical Reports Server (NTRS)

    Asano, S.; Sato, M.

    1980-01-01

    A study of the light scattering properties of randomly oriented, identical spheroidal particles is presented. A computation method was developed to integrate the Asano and Yamomoto solution (1975) for scattering from a homogeneous spheroid over all particle orientations; the extinction and scattering cross-sections, the asymmetry factor, and scattering matrix elements are calculated for randomly oriented prolate and oblate spheroids and compared with the calculations for spheres and laboratory measurements. The angular scattering behavior of spheroids is found to be different from that of the spheres for side scattering to backscattering directions, and prolate and oblate spheroids of the same shape parameter have similar angular scattering patterns.

  10. Angle-Resolved Second-Harmonic Light Scattering from Colloidal Particles

    SciTech Connect

    Yang, N.; Angerer, W. E.; Yodh, A. G.

    2001-09-03

    We report angle-resolved second-harmonic generation (SHG) measurements from suspensions of centrosymmetric micron-size polystyrene spheres with surface-adsorbed dye (malachite green). The second-harmonic scattering profiles differ qualitatively from linear light scattering profiles of the same particles. We investigated these radiation patterns using several polarization configurations and particle diameters. We introduce a simple Rayleigh-Gans-Debye model to account for the SHG scattering anisotropy. The model compares favorably with our experimental data. Our measurements suggest scattering anisotropy may be used to isolate particle nonlinear optics from other bulk nonlinear optical effects in suspension.

  11. Violation of a Bell-like inequality by a combination of Rayleigh scattering with a Mach-Zehnder setup

    NASA Astrophysics Data System (ADS)

    Rother, Tom

    2016-07-01

    In this paper I propose a classical optics experiment that results in a maximum violation of a Bell-like inequality. The first part is concerned with the Bell-like inequality (the so-called CHSH-inequality) itself. Its importance and its maximum violation in Quantum Mechanics (QM) are discussed in detail by employing an abstract probability state concept in a 4-dim. but classical event space. A T-matrix that represents the integral part of a corresponding Green's function as well as a statistical operator that contains a negative quasi-probability can be related to the corresponding quantum mechanical experiment. It is demonstrated that the derivation and usage of the T-matrix and the Green's function is equivalent to what is known from classical scattering theory. It is shown moreover that the negative quasi-probability of the statistical operator may be interpreted as a sink of probabilities related to two single events of the considered 4-dim. event space. A necessary condition for the violation of the CHSH-inequality is derived and discussed afterwards. In the second part of this paper I discuss a modification of the 4-dim. event space considered in the first part. It is shown that a combination of conventional Rayleigh scattering with a Mach-Zehnder setup would be able to put this modification into practice. Thus it becomes possible to achieve a maximum violation of the CHSH-inequality, if formulated in terms of intensities, on a pure classical way. The combination of classical light scattering with correlation experiments such as proposed in this paper may open new ways to study and to use the violation of Bell-like inequalities in modern optics.

  12. Highly efficient and two-photon excited stimulated Rayleigh-Bragg scattering in organic solutions

    NASA Astrophysics Data System (ADS)

    He, Guang S.; Prasad, Paras N.; Kannan, Ramamurthi; Tan, Loon-Seng

    2015-07-01

    The properties of backward stimulated Rayleigh-Bragg scattering (SRBS) in three highly two-photon active AF-chromophores solutions in tetrahydrofuran (THF) have been investigated using 816-nm and 8-ns pump laser beam. The nonlinear reflectivity R, spectral structure, temporal behavior, and phase-conjugation capability of the backward SRBS output have been measured, respectively. Under the same experimental condition, the pump threshold for SRBS in three solution samples can be significantly (˜one order of magnitude) lower than that for stimulated Brillouin scattering (SBS) in the pure solvent (THF). With the optimized concentration value and at a moderate pump energy (˜1.5 mJ) level, the measured nonlinear reflectivity was R ≥ 35% for the 2 cm-long solution sample, while for the SBS from a pure solvent sample of the same length was R ≈ 4.7%. The peculiar features of very low pump threshold, no spectral shift, tolerant pump spectral linewidth requirement (≤1 cm-1), and phase-conjugation capability are favorable for those nonlinear photonics applications, such as highly efficiency phase-conjugation reflectors for high-brightness laser oscillator/amplifier systems, special imaging through turbid medium, self-adaptive remote optical sensing, as well as for optical rangefinder and lidar systems.

  13. Temperature retrieval from Rayleigh-Brillouin scattering profiles measured in air.

    PubMed

    Witschas, Benjamin; Gu, Ziyu; Ubachs, Wim

    2014-12-01

    In order to investigate the performance of two different algorithms for retrieving temperature from Rayleigh-Brillouin (RB) line shapes, RB scattering measurements have been performed in air at a wavelength of 403 nm, for a temperature range from 257 K to 330 K, and atmospherically relevant pressures from 871 hPa to 1013 hPa. One algorithm, based on the Tenti S6 line shape model, shows very good accordance with the reference temperature. In particular, the absolute difference is always less than 2 K. A linear correlation yields a slope of 1.01 ± 0.02 and thus clearly demonstrates the reliability of the retrieval procedure. The second algorithm, based on an analytical line shape model, shows larger discrepancies of up to 9.9 K and is thus not useful at its present stage. The possible reasons for these discrepancies and improvements of the analytical model are discussed. The obtained outcomes are additionally verified with previously performed RB measurements in air, at 366 nm, temperatures from 255 K to 338 K and pressures from 643 hPa to 826 hPa [Appl. Opt. 52, 4640 (2013)]. The presented results are of relevance for future lidar studies that might utilize RB scattering for retrieving atmospheric temperature profiles with high accuracy. PMID:25606897

  14. Highly efficient and two-photon excited stimulated Rayleigh-Bragg scattering in organic solutions

    SciTech Connect

    He, Guang S. Prasad, Paras N.; Kannan, Ramamurthi; Tan, Loon-Seng

    2015-07-21

    The properties of backward stimulated Rayleigh-Bragg scattering (SRBS) in three highly two-photon active AF-chromophores solutions in tetrahydrofuran (THF) have been investigated using 816-nm and 8-ns pump laser beam. The nonlinear reflectivity R, spectral structure, temporal behavior, and phase-conjugation capability of the backward SRBS output have been measured, respectively. Under the same experimental condition, the pump threshold for SRBS in three solution samples can be significantly (∼one order of magnitude) lower than that for stimulated Brillouin scattering (SBS) in the pure solvent (THF). With the optimized concentration value and at a moderate pump energy (∼1.5 mJ) level, the measured nonlinear reflectivity was R ≥ 35% for the 2 cm-long solution sample, while for the SBS from a pure solvent sample of the same length was R ≈ 4.7%. The peculiar features of very low pump threshold, no spectral shift, tolerant pump spectral linewidth requirement (≤1 cm{sup −1}), and phase-conjugation capability are favorable for those nonlinear photonics applications, such as highly efficiency phase-conjugation reflectors for high-brightness laser oscillator/amplifier systems, special imaging through turbid medium, self-adaptive remote optical sensing, as well as for optical rangefinder and lidar systems.

  15. Absolute Rayleigh scattering cross sections of gases and freons of stratospheric interest in the visible and ultraviolet regions

    NASA Technical Reports Server (NTRS)

    SHARDANAND; Rao, A. D. P.

    1977-01-01

    The laboratory measurements of absolute Rayleigh scattering cross sections as a function wavelength are reported for gas molecules He, Ne, Ar, N2, H2, O2, CO2, CH4 and for vapors of most commonly used freons CCl2F2, CBrF3, CF4, and CHClf2. These cross sections are determined from the measurements of photon scattering at an angle of 54 deg 44 min which yield the absolute values independent of the value of normal depolarization ratios. The present results show that in the spectral range 6943-3638A deg, the values of the Rayleigh scattering cross section can be extrapolated from one wavelength to the other using 1/lambda (4) law without knowing the values of the polarizabilities. However, such an extrapolation can not be done in the region of shorter wavelengths.

  16. Hyper-Rayleigh scattering and hyper-Raman scattering of dye-adsorbed silver nanoparticles induced by a focused continuous-wave near-infrared laser

    SciTech Connect

    Itoh, Tamitake; Ozaki, Yukihiro; Yoshikawa, Hiroyuki; Ihama, Takashi; Masuhara, Hiroshi

    2006-02-20

    We report that hyper-Rayleigh scattering, surface-enhanced hyper-Raman scattering, and two-photon excited luminescence occur intermittently by focusing a continuous-wave near-infrared (cw-NIR) laser into a colloidal silver solution including rhodamine 6G (R6G) and sodium chloride (NaCl). On the other hand, continuous hyper-Rayleigh scattering is observed from colloidal silver free from R6G and NaCl, demonstrating that hyper-Raman scattering and two-photon excited luminescence are attributed to R6G and their intermittent features are dependent on the colloidal dispersion. These results suggest that the cw-NIR laser has three roles; the source of the nonlinear response, optical trapping of nanoparticles, and making nanoparticle aggregates possessing the high activity for the nonlinear response.

  17. Theory of Light Scattering in Axion Electrodynamics

    NASA Astrophysics Data System (ADS)

    Ochiai, Tetsuyuki

    2012-09-01

    Taking account of the axion term in the Maxwell Lagrangian, we present a rigorous theory of light scattering in piecewise-constant axion fields. In particular, we focus on axionic substances with confined and/or curved geometries, and the scattering matrices of an axionic slab, cylinder, and sphere are derived analytically. The axion term generates a surface current with off-diagonal optical conductivity, giving rise to a new type of photospin--orbit interaction. As a result, various novel light-scattering phenomena can take place. We demonstrate enhanced Faraday rotation, parity-violating light scattering, and strong perturbation of dipole radiation.

  18. Forward-peaked scattering of polarized light.

    PubMed

    Clark, Julia P; Kim, Arnold D

    2014-11-15

    Polarized light propagation in a multiple scattering medium is governed by the vector radiative transfer equation. We analyze the vector radiative transfer equation in asymptotic limit of forward-peaked scattering and derive an approximate system of equations for the Stokes parameters, which we call the vector Fokker-Planck approximation. The vector Fokker-Planck approximation provides valuable insight into several outstanding issues regarding the forward-peaked scattering of polarized light such as the polarization memory phenomenon. PMID:25490484

  19. Bidirectional scattering of light from tree leaves

    NASA Technical Reports Server (NTRS)

    Brakke, Thomas W.; Smith, James A.; Harnden, Joann M.

    1989-01-01

    A laboratory goniometer consisting of an He-Ne laser (632.8 nm), vertical leaf holder, and silicon photovoltaic detector was used to measure the bidirectional scattering (both transmittance and reflectance) of red oak and red maple. The illumination angles were 0, 30, and 60 deg, and the scattering was recorded approximately every 10 deg in the principal plane. The scattering profiles obtained show the non-Lambertian characteristics of the scattering, particularly for the off-nadir illumination directions. The transmitted light was more isotropic than the reflected light.

  20. Non-exponential Structural Relaxation, Anomalous Light Scattering, and Nanoscale Inhomogeneities in Glasses

    NASA Astrophysics Data System (ADS)

    Lee, M.; Moynihan, C. T.; Schroeder, J.

    1997-03-01

    Light scattering from glasses in the glass transition region exhibits an anomalous Rayleigh scattering. We observe a maximum in the scattering intensity versus temperature curves during heating. It is shown that this behavior is consistent with the presence of nanoscale inhomogeneities (density fluctions) which relax at different rates. Recent observations of anomalous light scattering were carried out on strong glass formers and fragile glass formers. In all cases a hysteresis effect is seen in the light scattering upon heating versus cooling each sample from room temperature through the glass transition region. From these measurements it is suggested that this could be the source of non-exponential structural relaxation kinetics. A model based upon the modified Tool-Narayanaswamy model is found to be in agreement with the calculations based on the experimental results.

  1. Calculation of the transport properties of carbon dioxide. III. Volume viscosity, depolarized Rayleigh scattering, and nuclear spin relaxation.

    PubMed

    Bock, Steffen; Bich, Eckard; Vogel, Eckhard; Dickinson, Alan S; Vesovic, Velisa

    2004-09-01

    Transport properties of pure carbon dioxide have been calculated from the intermolecular potential using the classical trajectory method. Results are reported in the dilute-gas limit for volume viscosity, depolarized Rayleigh scattering, and nuclear spin relaxation for temperatures ranging from 200 to 1000 K. Three recent carbon dioxide potential energy hypersurfaces have been investigated. Calculated values for the rotational collision number for all three intermolecular surfaces are consistent with the measurements and indicate that the temperature dependence of the Brau-Jonkman correlation is not applicable for carbon dioxide. The results for the depolarized Rayleigh scattering cross section and the nuclear spin relaxation cross section show that calculated values for the generally more successful potentials differ from the observations by 9% at about 290 K, although agreement is obtained for nuclear spin relaxation at about 400 K. PMID:15332957

  2. Coupling of a single diamond nanocrystal to a whispering-gallery microcavity: Photon transport benefitting from Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Liu, Yong-Chun; Xiao, Yun-Feng; Li, Bei-Bei; Jiang, Xue-Feng; Li, Yan; Gong, Qihuang

    2011-07-01

    We study the Rayleigh scattering induced by a diamond nanocrystal in a whispering-gallery-microcavity-waveguide coupling system and find that it plays a significant role in the photon transportation. On the one hand, this study provides insight into future solid-state cavity quantum electrodynamics aimed at understanding strong-coupling physics. On the other hand, benefitting from this Rayleigh scattering, effects such as dipole-induced transparency and strong photon antibunching can occur simultaneously. As a potential application, this system can function as a high-efficiency photon turnstile. In contrast to B. Dayan [ScienceSCIEAS0036-807510.1126/science.1152261 319, 1062 (2008)], the photon turnstiles proposed here are almost immune to the nanocrystal’s azimuthal position.

  3. Coupling of a single diamond nanocrystal to a whispering-gallery microcavity: Photon transport benefitting from Rayleigh scattering

    SciTech Connect

    Liu Yongchun; Xiao Yunfeng; Li Beibei; Jiang Xuefeng; Li Yan; Gong Qihuang

    2011-07-15

    We study the Rayleigh scattering induced by a diamond nanocrystal in a whispering-gallery-microcavity-waveguide coupling system and find that it plays a significant role in the photon transportation. On the one hand, this study provides insight into future solid-state cavity quantum electrodynamics aimed at understanding strong-coupling physics. On the other hand, benefitting from this Rayleigh scattering, effects such as dipole-induced transparency and strong photon antibunching can occur simultaneously. As a potential application, this system can function as a high-efficiency photon turnstile. In contrast to B. Dayan et al. [Science 319, 1062 (2008)], the photon turnstiles proposed here are almost immune to the nanocrystal's azimuthal position.

  4. Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10

    NASA Technical Reports Server (NTRS)

    Balla, R. Jeffrey; Everhart, Joel L.

    2012-01-01

    In an exploratory investigation, quantitative unclustered laser Rayleigh scattering measurements of density were performed in the air in the NASA Langley Research Center's 31 in. Mach 10 wind tunnel. A review of 20 previous years of data in supersonic and Mach 6 hypersonic flows is presented where clustered signals typically overwhelmed molecular signals. A review of nucleation theory and accompanying nucleation calculations are also provided to interpret the current observed lack of clustering. Data were acquired at a fixed stagnation temperature near 990Kat five stagnation pressures spanning 2.41 to 10.0 MPa (350 to 1454 psi) using a pulsed argon fluoride excimer laser and double-intensified charge-coupled device camera. Data averaged over 371 images and 210 pixels along a 36.7mmline measured freestream densities that agree with computed isentropic-expansion densities to less than 2% and less than 6% at the highest and lowest densities, respectively. Cluster-free Mach 10 results are compared with previous clustered Mach 6 and condensation-free Mach 14 results. Evidence is presented indicating vibrationally excited oxygen and nitrogen molecules are absorbed as the clusters form, release their excess energy, and inhibit or possibly reverse the clustering process. Implications for delaying clustering and condensation onset in hypersonic and hypervelocity facilities are discussed.

  5. Frequency-agile hyper-Rayleigh scattering studies of electro-optic chromophores

    NASA Astrophysics Data System (ADS)

    Firestone, Kimberly A.; Lao, David B.; Casmier, Daniel M.; Clot, Olivier; Dalton, Larry R.; Reid, Philip J.

    2005-08-01

    Hyper-Rayleigh scattering (HRS) is used to measure the first-hyperpolarizability (β) of electro-optic (EO) chromophores. One of the inherent concerns in any HRS measurement is the extent to which resonant enhancement contributes to the observed intensity thereby leading to inaccuracies when evaluating chromophore potential for application in electro-optical devices. One way to address this concern is to employ increasingly longer excitation wavelengths far from resonance. However, in charge-transfer-based non-linear optical chromophores, enhanced β generally correlates with a red-shift of the charge transfer absorption band so that even at the longest excitation wavelengths generally employed in HRS studies, resonant enhancement remains an issue. We have adopted an alternative approach in which the wavelength dispersion of the HRS intensity is determined by performing measurements at a variety of excitation wavelengths. This approach allows one to ascertain the role of resonance enhancement thereby allowing for more accurate correlation of improved β with molecular architecture. We report the results of our HRS studies for nine chromophores employing excitation wavelengths ranging from 780 to 1907 nm. Our HRS results demonstrate good agreement with the predictions of density functional theory. This synthesis of experimental and theoretical techniques has resulted in more effective designs for the next generations of electro-optical chromophores.

  6. Measurement of the thermal diffusivity of liquids by the forced Rayleigh scattering method: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Nagasaka, Y.; Hatakeyama, T.; Okuda, M.; Nagashima, A.

    1988-07-01

    This article is devoted to the theory and experiment of the forced Rayleigh scattering method for measurement of thermal diffusivity of liquids which can be employed in the form of an instrument operated optically in a contact-free manner. The theoretical considerations included are: (1) effect of cell wall, (2) effect of dye, (3) effect of Gaussian beam intensity distribution, (4) effect of heating duration time, and (5) effect of coupled dye and wall for a heavily absorbing sample. The errors caused by inadequate setting of optical conditions are also analyzed: (1) effects of grating thickness and (2) effects of initial temperature amplitude. Experimental verifications of the theory have been carried out through the measurements on toluene and water as standard reference substances. As a result of these experiments and theory, the criteria for optimum measuring conditions became available. To demonstrate the applicability of the present theory and the apparatus, the thermal diffusivities of toluene and methanol have been measured near room temperature under atmospheric pressure. The accuracy of the present measurement is estimated to be ±3%.

  7. Determination of thiram using gold nanoparticles and Resonance Rayleigh scattering method.

    PubMed

    Parham, Hooshang; Pourreza, Nahid; Marahel, Farzaneh

    2015-08-15

    A sensitive, simple and novel method was developed to determine thiram fungicide in water and plant samples. This method was based on the interaction between gold nanoparticles (AuNPs) and thiram fungicide followed by increasing of the Resonance Rayleigh scattering (RRS) intensity of nanoparticles. The change in RRS intensity (∆IRRS) was linearly correlated to the concentration of thiram over the range of 1.0-200.0µgL(-1). Thiram can be measured in a short time (4min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RRS intensities such as pH, concentration of AuNPs, standing time, electrolyte concentration, and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a very good selectivity and could be used conveniently for the determination of thiram. The limit of detection (LOD) and limit of quantification (LOQ) were 0.3 and 1.0µg L(-1), respectively. Relative standard deviations (RSD) for 20.0 and 80.0µg L(-1) of thiram were 3.0 and 1.1, respectively. Possible mechanisms for the RRS changes of AuNPs in the presence of thiram were discussed and the method was successfully applied for the analysis of spiked real water samples and fresh plant samples such as tomato and cucumber. PMID:25966394

  8. Characterization of the nonlinear optical properties of nanocrystals by Hyper Rayleigh Scattering

    PubMed Central

    2013-01-01

    Background Harmonic Nanoparticles are a new family of exogenous markers for multiphoton imaging exerting optical contrast by second harmonic (SH) generation. In this tutorial, we present the application of Hyper-Rayleigh Scattering (HRS) for a quantitative assessment of the nonlinear optical properties of these particles and discuss the underlying theory and some crucial experimental aspects. Methods The second harmonic properties of BaTiO3, KNbO3, KiTiOPO4 (KTP), LiNbO3 and ZnO nanocrystals (NCs) are investigated by HRS measurements after careful preparation and characterization of colloidal suspensions. Results A detailed analysis of the experimental results is presented with emphasis on the theoretical background and on the influence of some experimental parameters including the accurate determination of the nanocrystal size and concentration. The SH generation efficiency and averaged nonlinear optical coefficients are then derived and compared for six different types of NCs. Conclusions After preparation of colloidal NC suspensions and careful examination of their size, concentration and possible aggregation state, HRS appears as a valuable tool to quantitatively assess the SH efficiency of noncentrosymmetric NCs. All the investigated nanomaterials show high SH conversion efficiencies, demonstrating a good potential for bio-labelling applications. PMID:24564891

  9. Verification of radiative transfer results by inserting them into the RTE: A demonstration for Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Hollstein, André

    2012-10-01

    The verification of a new or updated radiative transfer model (RTM) is one of the important steps in its development; this is usually achieved by comparisons with real measurements or published tables of generally accepted radiative transfer results. If such tables do not exist, verification becomes more complicated and an external review of the implementation is often unpractical due to the sheer amount and complexity of the code. The presented verification approach is to “simply” insert results of radiative transfer (RT) calculations into the radiative transfer equation (RTE). The evaluation of the RTE consists of numerically calculating partial derivatives and integrals, which is much simpler to implement than a solution of the RTE. Presented is a demonstration of this approach for a case of Rayleigh scattering in a plane parallel atmosphere, which showed only very small deviation from the radiative transfer equation.This approach has two key benefits. First, its implementation into a high level computer language can be very short (≈60 lines in MATHEMATICA) and clear compared to a full RTM; and such code is much more easy to review. Second, this approach can be easily extended to cases where no other independent RT implementation is available for validation. The proposed implementation and data are provided with this paper.

  10. Hydride generation-resonance Rayleigh scattering and SERS spectral determination of trace Bi.

    PubMed

    Liang, Xiaojing; Wen, Guiqing; Liu, Qingye; Liang, Aihui; Jiang, Zhiliang

    2016-09-01

    In acidic solutions, Bi(III) was reduced by NaBH4 to form BiH3 gas. Using I3(-)graphene oxide (GO) as absorption solution, the BiH3 gas reacted with I3(-) to form I(-) that resulted in the I3(-) concentration decreasing. In the absence of BiH3, the I3(-) concentration was high, and as receptors it was closed to the surfaces of GO which was as donors. Then the surface plasmon resonance Rayleigh scattering (RRS) energy of GO transfers to I3(-) heavily, and results in the RRS quenching severely. With the increase of the Bi(III) concentration, the receptors and the RRS energy transfer (RRS-ET) decreased, so the RRS intensity enhanced linearly at 370nm. The RRS intensity was linear to the Bi(III) concentration in 0.05-5.5μmol/L, with a detection limit of 4ng/mL Bi. A new RRS-ET spectral method was developed for the determination of trace Bi(III). Using I3(-) as the absorption solution, silver nanorod (AgNR) as sol substrate and Vitoria blue B (VBB) as molecular probe, a SERS method was developed for detection of Bi. PMID:27214274

  11. Hydride generation-resonance Rayleigh scattering and SERS spectral determination of trace Bi

    NASA Astrophysics Data System (ADS)

    Liang, Xiaojing; Wen, Guiqing; Liu, Qingye; Liang, Aihui; Jiang, Zhiliang

    2016-09-01

    In acidic solutions, Bi(III) was reduced by NaBH4 to form BiH3 gas. Using I3- graphene oxide (GO) as absorption solution, the BiH3 gas reacted with I3- to form I- that resulted in the I3- concentration decreasing. In the absence of BiH3, the I3- concentration was high, and as receptors it was closed to the surfaces of GO which was as donors. Then the surface plasmon resonance Rayleigh scattering (RRS) energy of GO transfers to I3- heavily, and results in the RRS quenching severely. With the increase of the Bi(III) concentration, the receptors and the RRS energy transfer (RRS-ET) decreased, so the RRS intensity enhanced linearly at 370 nm. The RRS intensity was linear to the Bi(III) concentration in 0.05-5.5 μmol/L, with a detection limit of 4 ng/mL Bi. A new RRS-ET spectral method was developed for the determination of trace Bi(III). Using I3- as the absorption solution, silver nanorod (AgNR) as sol substrate and Vitoria blue B (VBB) as molecular probe, a SERS method was developed for detection of Bi.

  12. A simple and rapid resonance Rayleigh scattering method for detection of indigo carmine in soft drink.

    PubMed

    Li, Qin; Yang, Jidong; Tan, Xuanping; Zhang, Zhan; Hu, Xiaomei; Yang, Menghuan

    2016-08-01

    A novel method that uses acridine orange (AO) to detect indigo carmine (IC) in soft drinks was developed. The method is highly sensitive and is based on a resonance Rayleigh scattering (RRS) technique. In Britton-Robinson (BR) buffer solution, pH 4.3, the weak RRS intensity of AO was greatly enhanced by the addition of IC, with the maximum peak located at 332 nm. Under optimum conditions, it was found that the enhanced RRS intensity was proportional to the concentration of IC over a range of 2-32 × 10(-6)  mol/L. A low detection limit of 2.4 × 10(-8)  mol/L was achieved. The sensitivity and selectivity of the method are high enough to permit the determination of trace amounts of IC without any significant interference from high levels of other components such as common anions and other amino acids. Finally, the concentration of IC in three different soft drinks was determined with satisfactory results. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26791156

  13. Resonance Rayleigh scattering method for the determination of cationic surfactants with chromium(VI)-iodide system.

    PubMed

    Liu, Shaopu; Shi, Yan; Liu, Zhongfang; Luo, Hongqun; Kong, Ling

    2006-05-01

    A method for detecting and identifying cationic surfactant in some chemical samples for daily use that include Head & Shoulder Ampoule and Slek Shower Lotion has been developed. In an acid medium, chromium(VI) oxidizes I(-) to produce I(2), I(2) binds excess of I(-) to form I(3)(-), and I(3)(-) can further react with a cationic surfactant (CS) (such as cetyldimethyl benzylammonium chloride (CDBAC), Zephiramine (Zeph), cetylpyridinium bromide (CPB), tetradecyl pyridinium bromide (TPB) and cetyltrimethylammonium bromide (CTAB)) to form ion-association complexes [CS][I(3)]. This results in a significant enhancement of resonance Rayleigh scattering (RRS) and appearance of new RRS spectra. The RRS spectral characteristics of the ion-association complexes, the influencing factors and the optimum conditions of the reactions have been investigated. The intensities of RRS are directly proportional to the concentration of CS. CS in samples are collected using a treated anion exchange column and subsequently complexed by I(3)(-); then the RRS intensities of CS complex are determined at 495 nm. The reactions have high sensitivities, and their detection limits are 7.05 - 9.62 ng/mL for different CS. The effects of foreign substances are investigated and the results show that the method has good selectivity. PMID:16770060

  14. Resonance Rayleigh scattering method for highly sensitive detection of chitosan using aniline blue as probe.

    PubMed

    Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan

    2016-11-01

    This paper describes a highly sensitive and accurate approach using aniline blue (AB) (water soluble) as a probe to determine chitosan (CTS) through Resonance Rayleigh scattering (RRS). Under optimum experimental conditions, the intensities of RRS were linearly proportional to the concentration of CTS in the range from 0.01 to 3.5μg/mL, and the limit of detection (LOD) was 6.94ng/mL. Therefore, a new and highly sensitive method based on RRS for the determination of CTS has been developed. Furthermore, the effect of molecular weight of CTS and the effect of the degree of deacetylation of CTS on the accurate quantification of CTS was studied. The experimental data was analyzed by linear regression analysis, which indicated that the molecular weight and the degree of deacetylation of CTS had no statistical significance and this method could be used to determine CTS accurately. Meanwhile, this assay was applied for CTS determination in health products with satisfactory results. PMID:27294549

  15. Light-scattering theory of diffraction.

    PubMed

    Guo, Wei

    2010-03-01

    Since diffraction is a scattering process in principle, light propagation through one aperture in a screen is discussed in the light-scattering theory. Through specific calculation, the expression of the electric field observed at an observation point is obtained and is used not only to explain why Kirchhoff's diffraction theory is a good approximation when the screen is both opaque and sufficiently thin but also to demonstrate that the mathematical and physical problems faced by Kirchhoff's theory are avoided in the light-scattering theory. PMID:20208939

  16. Correction of sunspot intensities for scattered light

    NASA Technical Reports Server (NTRS)

    Mullan, D. J.

    1973-01-01

    Correction of sunspot intensities for scattered light usually involves fitting theoretical curves to observed aureoles (Zwaan, 1965; Staveland, 1970, 1972). In this paper we examine the inaccuracies in the determination of scattered light by this method. Earlier analyses are extended to examine uncertainties due to the choice of the expression for limb darkening. For the spread function, we consider Lorentzians and Gaussians for which analytic expressions for the aureole can be written down. Lorentzians lead to divergence and normalization difficulties, and should not be used in scattered light determinations. Gaussian functions are more suitable.

  17. The polarization of continuum radiation in sunspots. I - Rayleigh and Thomson scattering

    NASA Technical Reports Server (NTRS)

    Finn, G. D.; Jefferies, J. T.

    1974-01-01

    Expressions are derived for the Stokes parameters of light scattered by a layer of free electrons and hydrogen atoms in a sunspot. A physically reasonable sunspot model was found so that the direction of the calculated linear polarization agrees reasonably with observations. The magnitude of the calculated values of the linear polarization agrees generally with values observed in the continuum at 5830 A. Circular polarization in the continuum also accompanies electron scattering in spot regions; however for commonly accepted values of the longitudinal magnetic field, the predicted circular polarization is much smaller than observed.

  18. Half space albedo problem for the nonconservative vector equation of transfer with a combination of Rayleigh and isotropic scattering

    NASA Astrophysics Data System (ADS)

    Şenyiğit, M.

    2016-09-01

    The half-space albedo problem has been solved for a combination of Rayleigh and isotropic scattering using HN method which is developed for the neutron transport studies. The numerical results are compared with exact values obtained using variational method and Chandrasekhar's equation for the {H}-matrix. The analytical solutions of HN method are easy to handle in comparison with the other methods. The numerical results are in good agreement with previous works in literature.

  19. Ultrasensitive detection of target analyte-induced aggregation of gold nanoparticles using laser-induced nanoparticle Rayleigh scattering.

    PubMed

    Lin, Jia-Hui; Tseng, Wei-Lung

    2015-01-01

    Detection of salt- and analyte-induced aggregation of gold nanoparticles (AuNPs) mostly relies on costly and bulky analytical instruments. To response this drawback, a portable, miniaturized, sensitive, and cost-effective detection technique is urgently required for rapid field detection and monitoring of target analyte via the use of AuNP-based sensor. This study combined a miniaturized spectrometer with a 532-nm laser to develop a laser-induced Rayleigh scattering technique, allowing the sensitive and selective detection of Rayleigh scattering from the aggregated AuNPs. Three AuNP-based sensing systems, including salt-, thiol- and metal ion-induced aggregation of the AuNPs, were performed to examine the sensitivity of laser-induced Rayleigh scattering technique. Salt-, thiol-, and metal ion-promoted NP aggregation were exemplified by the use of aptamer-adsorbed, fluorosurfactant-stabilized, and gallic acid-capped AuNPs for probing K(+), S-adenosylhomocysteine hydrolase-induced hydrolysis of S-adenosylhomocysteine, and Pb(2+), in sequence. Compared to the reported methods for monitoring the aggregated AuNPs, the proposed system provided distinct advantages of sensitivity. Laser-induced Rayleigh scattering technique was improved to be convenient, cheap, and portable by replacing a diode laser and a miniaturized spectrometer with a laser pointer and a smart-phone. Using this smart-phone-based detection platform, we can determine whether or not the Pb(2+) concentration exceed the maximum allowable level of Pb(2+) in drinking water. PMID:25476277

  20. High performance liquid chromatography coupled with resonance Rayleigh scattering for the detection of three fluoroquinolones and mechanism study

    NASA Astrophysics Data System (ADS)

    Zhou, Mingqiong; Peng, Jingdong; He, Rongxing; He, Yuting; Zhang, Jing; Li, Aiping

    2015-02-01

    A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N = 3) of 0.05-0.12 μg mL-1 was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method.

  1. Microscopic Imaging and Spectroscopy with Scattered Light

    PubMed Central

    Boustany, Nada N.; Boppart, Stephen A.; Backman, Vadim

    2012-01-01

    Optical contrast based on elastic scattering interactions between light and matter can be used to probe cellular structure and dynamics, and image tissue architecture. The quantitative nature and high sensitivity of light scattering signals to subtle alterations in tissue morphology, as well as the ability to visualize unstained tissue in vivo, has recently generated significant interest in optical scatter based biosensing and imaging. Here we review the fundamental methodologies used to acquire and interpret optical scatter data. We report on recent findings in this field and present current advances in optical scatter techniques and computational methods. Cellular and tissue data enabled by current advances in optical scatter spectroscopy and imaging stand to impact a variety of biomedical applications including clinical tissue diagnosis, in vivo imaging, drug discovery and basic cell biology. PMID:20617940

  2. Deep Water Cherenkov Light Scatter Meter

    SciTech Connect

    Pappalardo, L; Petta, C.; Russo, G.V.

    2000-12-31

    The relevant parameters for the site choice of an underwater neutrino's telescope are discussed. The in situ measurement of the scattering distribution of the cherenkov light requires a suitable experimental setup. Its main features are described here.

  3. Light scattering and birefrigence by magnetic bacteria

    SciTech Connect

    Johnston, R.G.; Jacobson, P.L.

    1990-01-01

    The bacterium Aquaspirillum magnetotacticum grows its own internal single domain magnets. For a number of reasons, these magnets make the bacterium an extremely interesting scattering particle. We are engaging in light scattering and birefringence studies on Aquaspirillum magnetotacticum. 9 refs., 4 figs.

  4. A novel method for the determination of fast green in grape wine based on resonance Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Li, Qin; Tan, Xuanping; Zheng, Xiaobo; Tang, Weiwei; Yang, Jidong

    2015-11-01

    A novel resonance Rayleigh scattering method was developed for the determination of fast green (FCF) in grape wine. In pH 2.5 Britton Robinson (BR) buffer solution, the scattering signal of acridine orange (AO) was remarkably enhanced after adding trace amount of FCF and forming an ion-association complex, which not only resulted in the change of absorption spectrum, fluorescence spectra, but also led to a significant enhancement of resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS), and second order scattering (SOS). The linear ranges and detection limits for RRS, SOS and FDS were 2-45 × 10-6 mol L-1, 2-24 × 10-6 mol L-1, 2-20 × 10-6 mol L-1, and 8.0 × 10-8 mol L-1, 4.7 × 10-7 mol L-3, 1.0 × 10-7 mol L-3, respectively. In this work, the optimum conditions, the influencing factors and the effects of coexisting substances on the reaction were investigated. The method can be applied to the determination of FCF in grape wine and the results were satisfactory.

  5. Microscope spectrometer for light scattering investigations

    SciTech Connect

    Barbara, Aude; Lopez-Rios, Tomas; Dumont, Sylvain; Gay, Frederic; Quemerais, Pascal

    2010-08-01

    We describe a setup including a microscope to study volumes of a few {mu}m{sup 3} by static and dynamic light scattering (DLS) in a backscattering configuration. Light scattered by individual objects of micrometric size can be analyzed in the 400-800 nm spectral range. This setup can also be employed to study both diluted and concentrated colloidal solutions by DLS measurements. For diluted solutions we found evidence of the fluctuations of the number of particles in a confocal volume. We discuss their contribution to the autocorrelation function of the scattered intensity measured as a function of time.

  6. Effect of molecular anisotropy on the intensity and degree of polarization of light scattered from model atmospheres

    NASA Technical Reports Server (NTRS)

    Bahethi, O. P.; Fraser, R. S.

    1975-01-01

    Computations of the intensity, flux, degree of polarization, and the positions of neutral points are presented for models of the terrestrial gaseous and hazy atmospheres by incorporating the molecular anisotropy due to air in the Rayleigh scattering optical thickness and phase matrix. Molecular anisotropy causes significant changes in the intensity, flux and the degree of polarization of the scattered light. The positions of neutral points do not change significantly. When the Rayleigh scattering optical thickness is kept constant and the molecular anisotropy factor is included only in the Rayleigh phase matrix, the flux does not change and the intensity and positions of neutron points change by a small amount. The changes in the degree of polarization are still significant.

  7. Scalar gradient trajectory measurements using high-frequency cinematographic planar Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Gampert, Markus; Narayanaswamy, Venkat; Peters, Norbert

    2013-12-01

    In this work, we perform an experimental investigation into statistics based on scalar gradient trajectories in a turbulent jet flow, which have been suggested as an alternative means to analyze turbulent flow fields by Wang and Peters (J Fluid Mech 554:457-475, 2006, 608:113-138, 2008). Although there are several numerical simulations and theoretical works that investigate the statistics along gradient trajectories, only few experiments in this area have been reported. To this end, high-frequency cinematographic planar Rayleigh scattering imaging is performed at different axial locations of a turbulent propane jet issuing into a CO2 coflow at nozzle-based Reynolds numbers Re 0 = 3,000-8,600. Taylor's hypothesis is invoked to obtain a three-dimensional reconstruction of the scalar field in which then the corresponding scalar gradient trajectories can be computed. These are then used to examine the local structure of the mixture fraction with a focus on the scalar turbulent/non-turbulent interface. The latter is a layer that is located between the fully turbulent part of the jet and the outer flow. Using scalar gradient trajectories, we partition the turbulent scalar field into these three regions according to an approach developed by Mellado et al. (J Fluid Mech 626:333-365, 2009). Based on the latter, we investigate the probability to find the respective regions as a function of the radial distance to the centerline, which turns out to reveal the meandering nature of the scalar T/NT interface layer as well as its impact on the local structure of the turbulent scalar field.

  8. SEARCH FOR RAYLEIGH SCATTERING IN THE ATMOSPHERE OF GJ1214b

    SciTech Connect

    De Mooij, E. J. W.; Jayawardhana, R.; Brogi, M.; Snellen, I. A. G.; Hoekstra, H.; Otten, G. P. P. L.; Bekkers, D. H.; Haffert, S. Y.; Van Houdt, J. J.; De Kok, R. J.; Croll, B.

    2013-07-10

    We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet toward the blue. We observed the transit of GJ1214b in the B band with the FOcal Reducing Spectrograph at the Very Large Telescope and in the g band with both ACAM on the William Herschel Telescope (WHT) and the Wide Field Camera at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B band of 0.1162 {+-} 0.0017, and in the g band 0.1180 {+-} 0.0009 and 0.1174 {+-} 0.0017 for the WHT and INT observations, respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered, a small scale-height water-dominated model fits the data best.

  9. Retrieval of temperature from a multiple-channel Rayleigh-scatter lidar using an optimal estimation method.

    PubMed

    Sica, R J; Haefele, A

    2015-03-10

    The measurement of temperature in the middle atmosphere with Rayleigh-scatter lidars is an important technique for assessing atmospheric change. Current retrieval schemes for this temperature have several shortcomings, which can be overcome by using an optimal estimation method (OEM). Forward models are presented that completely characterize the measurement and allow the simultaneous retrieval of temperature, dead time, and background. The method allows a full uncertainty budget to be obtained on a per profile basis that includes, in addition to the statistical uncertainties, the smoothing error and uncertainties due to Rayleigh extinction, ozone absorption, lidar constant, nonlinearity in the counting system, variation of the Rayleigh-scatter cross section with altitude, pressure, acceleration due to gravity, and the variation of mean molecular mass with altitude. The vertical resolution of the temperature profile is found at each height, and a quantitative determination is made of the maximum height to which the retrieval is valid. A single temperature profile can be retrieved from measurements with multiple channels that cover different height ranges, vertical resolutions, and even different detection methods. The OEM employed is shown to give robust estimates of temperature, which are consistent with previous methods, while requiring minimal computational time. This demonstrated success of lidar temperature retrievals using an OEM opens new possibilities in atmospheric science for measurement integration between active and passive remote sensing instruments. PMID:25968361

  10. Fiber optic probe for light scattering measurements

    DOEpatents

    Nave, Stanley E.; Livingston, Ronald R.; Prather, William S.

    1995-01-01

    A fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman-scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.

  11. Fiber optic probe for light scattering measurements

    DOEpatents

    Nave, S.E.; Livingston, R.R.; Prather, W.S.

    1993-01-01

    This invention is comprised of a fiber optic probe and a method for using the probe for light scattering analyses of a sample. The probe includes a probe body with an inlet for admitting a sample into an interior sample chamber, a first optical fiber for transmitting light from a source into the chamber, and a second optical fiber for transmitting light to a detector such as a spectrophotometer. The interior surface of the probe carries a coating that substantially prevents non-scattered light from reaching the second fiber. The probe is placed in a region where the presence and concentration of an analyte of interest are to be detected, and a sample is admitted into the chamber. Exciting light is transmitted into the sample chamber by the first fiber, where the light interacts with the sample to produce Raman-scattered light. At least some of the Raman- scattered light is received by the second fiber and transmitted to the detector for analysis. Two Raman spectra are measured, at different pressures. The first spectrum is subtracted from the second to remove background effects, and the resulting sample Raman spectrum is compared to a set of stored library spectra to determine the presence and concentration of the analyte.

  12. The Whiteness of Things and Light Scattering

    ERIC Educational Resources Information Center

    Gratton, L. M.; Lopez-Arias, T.; Calza, G.; Oss, S.

    2009-01-01

    We discuss some simple experiments dealing with intriguing properties of light and its interaction with matter. In particular, we show how to emphasize that light reflection, refraction and scattering can provide a proper, physical description of human perception of the "colour" white. These experiments can be used in the classroom with an enquiry…

  13. Shear Brillouin light scattering microscope.

    PubMed

    Kim, Moonseok; Besner, Sebastien; Ramier, Antoine; Kwok, Sheldon J J; An, Jeesoo; Scarcelli, Giuliano; Yun, Seok Hyun

    2016-01-11

    Brillouin spectroscopy has been used to characterize shear acoustic phonons in materials. However, conventional instruments had slow acquisition times over 10 min per 1 mW of input optical power, and they required two objective lenses to form a 90° scattering geometry necessary for polarization coupling by shear phonons. Here, we demonstrate a confocal Brillouin microscope capable of detecting both shear and longitudinal phonons with improved speeds and with a single objective lens. Brillouin scattering spectra were measured from polycarbonate, fused quartz, and borosilicate in 1-10 s at an optical power level of 10 mW. The elastic constants, phonon mean free path and the ratio of the Pockels coefficients were determined at microscopic resolution. PMID:26832263

  14. Polarization of light scattered by clover

    NASA Technical Reports Server (NTRS)

    Woessner, Paul; Hapke, Bruce

    1987-01-01

    This study was undertaken in order to better understand the factors that govern the polarization of light scattered from vegetation and soils. This phenomenon is not well understood but is potentially of interest for remote sensing of the earth. The intensity and polarization of light scattered by clover in vivo and soil were measured at a number of different angles of incidence and reflectance. Both individual leaves and natural patches of vegetation were measured. The Umov effect, or inverse relation between polarization and reflectance noted by many earlier workers, was observed here and is shown to be a very general property of diffusely scattering surfaces. The light transmitted through the leaves was found to be negatively polarized. The polarization of light scattered from aggregations of leaves is affected by this negatively polarized, transmitted light. The light scattered from the upper leaf surfaces was found to be positively polarized in a manner which could be accounted for quantitatively by specular Fresnel reflection from small, randomly oriented facets on the surfaces of the leaves.

  15. Circularly symmetric light scattering from nanoplasmonic spirals.

    PubMed

    Trevino, Jacob; Cao, Hui; Dal Negro, Luca

    2011-05-11

    In this paper, we combine experimental dark-field imaging, scattering, and fluorescence spectroscopy with rigorous electrodynamics calculations in order to investigate light scattering from planar arrays of Au nanoparticles arranged in aperiodic spirals with diffuse, circularly symmetric Fourier space. In particular, by studying the three main types of Vogel's spirals fabricated by electron-beam lithography on quartz substrates, we demonstrate polarization-insensitive planar light diffraction in the visible spectral range. Moreover, by combining dark-field imaging with analytical multiparticle calculations in the framework of the generalized Mie theory, we show that plasmonic spirals support distinctive structural resonances with circular symmetry carrying orbital angular momentum. The engineering of light scattering phenomena in deterministic structures with circular Fourier space provides a novel strategy for the realization of optical devices that fully leverage on enhanced, polarization-insensitive light-matter coupling over planar surfaces, such as thin-film plasmonic solar cells, plasmonic polarization devices, and optical biosensors. PMID:21466155

  16. Confocal detection of Rayleigh scattering for residual stress measurement in chemically tempered glass

    SciTech Connect

    Hödemann, S. Möls, P.; Kiisk, V.; Saar, R.; Kikas, J.; Murata, T.

    2015-12-28

    A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na{sup +} ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.

  17. Confocal detection of Rayleigh scattering for residual stress measurement in chemically tempered glass

    NASA Astrophysics Data System (ADS)

    Hödemann, S.; Möls, P.; Kiisk, V.; Murata, T.; Saar, R.; Kikas, J.

    2015-12-01

    A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of scattered laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na+ ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional scattered light tomography of mechanical imaging in birefringent materials.

  18. Particle optics in the Rayleigh regime.

    PubMed

    Moosmüller, Hans; Arnott, W Patrick

    2009-09-01

    Light scattering and absorption by particles suspended in the atmosphere modifies the transfer of solar energy in the atmosphere, thereby influencing global and regional climate change and atmospheric visibility. Of particular interest are the optical properties of particles in the Rayleigh regime, where particles are small compared with the wavelength of the scattered or absorbed light, because these particles experience little gravitational settlement and may have long atmospheric lifetimes. Optical properties of particles in the Rayleigh regime are commonly derived from electromagnetic theory using Maxwell's equations and appropriate boundary conditions. The size dependence of particle scattering and absorption are derived here from the most basic principles for coherent processes such as Rayleigh scattering (i.e., add amplitudes if in phase) and incoherent processes such as absorption (i.e., add cross sections), at the same time yielding understanding of the upper particle size limit for the Rayleigh regime. The wavelength dependence of Rayleigh scattering and absorption are also obtained by adding a basic scale invariance for particle optics. Simple consequences for particle single-scattering albedo ("whiteness") and the optical measurement of particle mass densities are explained. These alternative derivations complement the conventional understanding obtained from electromagnetic theory. PMID:19785268

  19. Light scattering study of rheumatoid arthritis

    SciTech Connect

    Beuthan, J; Netz, U; Minet, O; Mueller, G; Scheel, A; Henniger, J

    2002-11-30

    The distribution of light scattered by finger joints is studied in the near-IR region. It is shown that variations in the optical parameters of the tissue (scattering coefficient {mu}{sub s}, absorption coefficient {mu}{sub a}, and anisotropy factor g) depend on the presence of the rheumatoid arthritis (RA). At the first stage, the distribution of scattered light was measured in diaphanoscopic experiments. The convolution of a Gaussian error function with the scattering phase function proved to be a good approximation of the data obtained. Then, a new method was developed for the reconstruction of distribution of optical parameters in the finger cross section. Model tests of the quality of this reconstruction method show good results. (laser biology and medicine)

  20. Light Scattering Study on SWNTs Solutions

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Liu, Tao; Veedu Sreekumar, T.; Kumar, Satish; Tannenbaum, Rina; Moore, Vallerie; Hauge, R. H.; Smalley, R. E.

    2003-03-01

    SWNT/Oleum dispersions are being used to form film and fibers showing high electrical conductivity. PVP wrapped SWNTs have also been dissolved in aqueous medium. Light scattering studies have been performed in this study to understand the nanotube dispersion on both SWNT/Oleum as well as PVP/SWNT/surfactant/water dispersions. Preliminary studies on PVP wrapped SWNTs/water and SWNTs/oleum dispersion system show the existence of a critical concentration (c*) of SWNTs. Below c*, the detected scattering intensity increases with concentration; and above c*, the detected scattering intensity decreases with concentration. This observed phenomenon is attributed to the competition of scattering and strong absorption of SWNTs to visible light. Based on this study, level of SWNT dispersion is being studied. Results of these studies will be reported.

  1. Angular resolved light scattering for discriminating among marine picoplankton: modeling and experimental measurements

    NASA Astrophysics Data System (ADS)

    Shao, Bing; Jaffe, Jules S.; Chachisvilis, Mirianas; Esener, Sadik C.

    2006-12-01

    In order to assess the capability to optically identify small marine microbes, both simulations and experiments of angular resolved light scattering (ARLS) were performed. After calibration with 30-nm vesicles characterized by a nearly constant scattering distribution for vertically polarized light (azimuthal angle=90°), ARLS from suspensions of three types of marine picoplankton (two prokaryotes and one eukaryote) in seawater was measured with a scattering device that consisted of an elliptical mirror, a rotating aperture, and a PMT. Scattered light was recorded with adequate signal-to-noise in the 40-140°. Simulations modeled the cells as prolate spheroids with independently measured dimensions. For the prokaryotes, approximated as homogeneous spheroids, simulations were performed using the RM (Rayleigh-Mie) - I method, a hybrid of the Rayleigh-Debye approximation and the generalized Lorentz-Mie theory. For the picoeukaryote, an extended RM - I method was developed for a coated spheroid with different shell thickness distributions. The picoeukaryote was then modeled as a coated sphere with a spherical core. Good overall agreements were obtained between simulations and experiments. The distinctive scattering patterns of the different species hold promise for an identification system based on ARLS.

  2. Laser light scattering instrument advanced technology development

    NASA Technical Reports Server (NTRS)

    Wallace, J. F.

    1993-01-01

    The objective of this advanced technology development (ATD) project has been to provide sturdy, miniaturized laser light scattering (LLS) instrumentation for use in microgravity experiments. To do this, we assessed user requirements, explored the capabilities of existing and prospective laser light scattering hardware, and both coordinated and participated in the hardware and software advances needed for a flight hardware instrument. We have successfully breadboarded and evaluated an engineering version of a single-angle glove-box instrument which uses solid state detectors and lasers, along with fiber optics, for beam delivery and detection. Additionally, we have provided the specifications and written verification procedures necessary for procuring a miniature multi-angle LLS instrument which will be used by the flight hardware project which resulted from this work and from this project's interaction with the laser light scattering community.

  3. Light scattering by aggregated red blood cells.

    PubMed

    Tsinopoulos, Stephanos V; Sellountos, Euripides J; Polyzos, Demosthenes

    2002-03-01

    In low flow rates, red blood cells (RBCs) fasten together along their axis of symmetry and form a so-called rouleaux. The scattering of He-Ne laser light by a rouleau consisting of n (2 < or = n < or = 8) average-sized RBCs is investigated. The interaction problem is treated numerically by means of an advanced axisymmetric boundary element--fast Fourier transform methodology. The scattering problem of one RBC was solved first, and the results showed that the influence of the RBC's membrane on the scattering patterns is negligible. Thus the rouleau is modeled as an axisymmetric, homogeneous, low-contrast dielectric cylinder, on the surface of which appears, owing to aggregated RBCs, a periodic roughness along the direction of symmetry. The direction of the incident laser light is considered to be perpendicular to the scatterer's axis of symmetry. The differential scattering cross sections in both perpendicular and parallel scattering planes and for all the scattering angles are calculated and presented in detail. PMID:11900021

  4. Light scattering by aggregated red blood cells

    NASA Astrophysics Data System (ADS)

    Tsinopoulos, Stephanos V.; Sellountos, Euripides J.; Polyzos, Demosthenes

    2002-03-01

    In low flow rates, red blood cells (RBCs) fasten together along their axis of symmetry and form a so-called rouleaux. The scattering of He-Ne laser light by a rouleau consisting of n (2 less-than-or-equal n less-than-or-equal 8) average-sized RBCs is investigated. The interaction problem is treated numerically by means of an advanced axisymmetric boundary element--fast Fourier transform methodology. The scattering problem of one RBC was solved first, and the results showed that the influence of the RBC's membrane on the scattering patterns is negligible. Thus the rouleau is modeled as an axisymmetric, homogeneous, low-contrast dielectric cylinder, on the surface of which appears, owing to aggregated RBCs, a periodic roughness along the direction of symmetry. The direction of the incident laser light is considered to be perpendicular to the scatterer's axis of symmetry. The differential scattering cross sections in both perpendicular and parallel scattering planes and for all the scattering angles are calculated and presented in detail.

  5. Study on the interaction between fluoroquinolones and erythrosine by absorption, fluorescence and resonance Rayleigh scattering spectra and their application

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Liu, Zhongfang; Liu, Jiangtao; Liu, Shaopu; Shen, Wei

    2008-03-01

    In pH 4.4-4.5 Britton-Robinson (BR) buffer solution, fluoroquinolone antibiotics (FLQs) including ciprofloxacin (CIP), norfloxacin (NOR), levofloxacin (LEV) and lomefloxacin (LOM) could react with erythrosine (Ery) to form 1:1 ion-association complexes, which not only resulted in the changes of the absorption spectra and the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS). These offered some indications of the determination of fluoroquinolone antibiotics by spectrophotometric, fluorescence and resonance Rayleigh scattering methods. The detection limits for fluoroquinolone antibiotics were in the range of 0.097-0.265 μg/mL for absorption methods, 0.022-0.100 μg/mL for fluorophotometry and 0.014-0.027 μg/mL for RRS method, respectively. Among them, the RRS method had the highest sensitivity. In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions and the properties of the analytical chemistry were investigated. The methods have been successfully applied to determination of some fluoroquinolone antibiotics in human urine samples and tablets. Taking CIP-Ery system as an example, the charge distribution, the enthalpy of formation and the mean polarizability were calculated by density function theory (DFT) method. In addition, the reasons for the enhancement of scattering spectra were discussed.

  6. An automatic light scattering CCN counter

    NASA Technical Reports Server (NTRS)

    Lala, G. G.

    1981-01-01

    The counter is a static thermal diffusion chamber which has been modified to include an optical system for the determination of droplet concentration by the measurement of scattered light. The determination of concentration is made by measurement of the peak scattered light signal from the cloud of growing droplets which is a function of both the droplet concentration and chamber supersaturation. Because the formation of the peak is related to the rate of growth of the droplets and sedimentation, both of which are determined by supersaturation, the system calibration can be uniquely determined by comparison with an absolute counter such as a static diffusion chamber with a photographic recording system.

  7. An automatic light scattering CCN counter

    NASA Astrophysics Data System (ADS)

    Lala, G. G.

    1981-11-01

    The counter is a static thermal diffusion chamber which has been modified to include an optical system for the determination of droplet concentration by the measurement of scattered light. The determination of concentration is made by measurement of the peak scattered light signal from the cloud of growing droplets which is a function of both the droplet concentration and chamber supersaturation. Because the formation of the peak is related to the rate of growth of the droplets and sedimentation, both of which are determined by supersaturation, the system calibration can be uniquely determined by comparison with an absolute counter such as a static diffusion chamber with a photographic recording system.

  8. Flexible detection optics for light scattering

    NASA Astrophysics Data System (ADS)

    Taratuta, Victor G.; Hurd, Alan J.; Meyer, Robert B.

    1984-05-01

    We have designed and built a compact, modular apparatus for the collection, viewing, and detection of scattered light for less than 1200, based on a commercially available optical bench. The novelty of our instrument is that it has the flexibility of modular design while allowing the user to see exactly what is happening: both the real image of the sample and the spatial coherence of the scattered light can be examined. There is built-in control over polarization, filtering, magnification, and other parameters.

  9. Light scattering from cylindrical structures on surfaces.

    PubMed

    Taubenblatt, M A

    1990-03-01

    Light scattering from a dielectric cylindrical structure on a surface by a plane wave with field vector along the cylinder axis is calculated with a modification of the coupled-dipole method. The interaction matrix is calculated with the use of both the direct contribution of a polarization current filament and its reflection from the surface. The reflected cylindrical waves are computed with the use of the Sommerfeld-type integral expression. Light scattering from structures of arbitrary cross section and the size of the order of a wavelength can be quickly determined with this method. PMID:19759774

  10. Improvements in filtered Rayleigh scattering measurements using Fabry-Perot etalons for spectral filtering of pulsed, 532-nm Nd:YAG output

    NASA Astrophysics Data System (ADS)

    Sutton, Jeffrey A.; Patton, Randy A.

    2014-09-01

    In this manuscript, we investigate a new methodology for increasing the spectral purity of the second-harmonic output of an injection-seeded, frequency-doubled, Q-switched Nd:YAG laser operating near 532 nm. Specifically, tunable Fabry-Perot etalons (FPEs) are used as ultra-narrowband spectral filters, transmitting the desired single-mode output, while filtering out a significant portion of the broadband pedestal characteristic of injection-seeded lasers. A specific emphasis is placed on the design and optimization of the FPEs in the context of filtered Rayleigh scattering (FRS) measurements and how their utilization results in substantial increases in spectral purity, realizable attenuation of unwanted scattering, and applications in environments with high particulate levels. Experimental results show an increase in laser spectral purity of more than one order-of-magnitude (from 0.99997 to 0.999998) when using FPE filters, which led to a two-order-of-magnitude increase in achievable attenuation of laser light passing through a molecular iodine filter. The utility of the FPE-based spectral filtering of the pulsed Nd:YAG output for 2D FRS imaging was demonstrated in turbulent, isothermal gas-phase jets, seeded with varying levels of non-evaporating droplets with particle volume fractions ( F Vp) ranging from ~5 to >60 parts-per-million (ppm). After implementation of an optimized air-spaced FPE in the 532-nm output, no particle scattering was observed (based on visual and statistical analysis), even for the highest seed case ( F Vp ~ 60 ppm), and the gas-phase Rayleigh-Brillouin signals were collected without interference from the flowfield particulate. The current results suggest that the implementation of properly specified FPEs allows FRS to be applied in environments with high flowfield particulate levels; levels are well beyond what have been suitable for previous FRS measurements.

  11. Effects of refraction on transmission spectra of gas giants: decrease of the Rayleigh scattering slope and breaking of retrieval degeneracies

    NASA Astrophysics Data System (ADS)

    Bétrémieux, Yan

    2016-03-01

    Detection of the signature of Rayleigh scattering in the transmission spectrum of an exoplanet is increasingly becoming the target of observational campaigns because the spectral slope of the Rayleigh continuum enables one to determine the scaleheight of its atmosphere in the absence of hazes. However, this is only true when one ignores the refractive effects of the exoplanet's atmosphere. I illustrate with a suite of simple isothermal clear Jovian H2-He atmosphere models with various abundances of water that refraction can decrease significantly the spectral slope of the Rayleigh continuum and that it becomes flat in the infrared. This mimics a surface, or an optically thick cloud deck, at much smaller pressures than one can probe in the non-refractive case. The relative impact of refraction on an exoplanet's transmission spectrum decreases with atmospheric temperatures and increases with stellar temperature. Refraction is quite important from a retrieval's perspective for Jovian-like planets even at the highest atmospheric temperatures (1200 K) considered in this paper, and for all stellar spectral types. Indeed, refraction breaks in large part the retrieval degeneracy between abundances of chemical species and the planet's radius because the size of spectral features increases significantly with abundances, in stark contrast with the non-refractive case which simply shifts them to a larger or smaller effective radius. Abundances inferred assuming that the atmosphere is cloud-free are lower limits. These results show how important it is to include refraction in retrieval algorithms to interpret transmission spectra of gas giants accurately.

  12. Calibration of photomultiplier tubes for the fluorescence detector of telescope array experiment using a Rayleigh scattered laser beam

    NASA Astrophysics Data System (ADS)

    Kawana, Shingo; Sakurai, Nobuyuki; Fujii, Toshihiro; Fukushima, Masaki; Inoue, Naoya; Matthews, John N.; Ogio, Shoichi; Sagawa, Hiroyuki; Taketa, Akimichi; Takita, Masato; Thomas, Stan B.; Tokuno, Hisao; Tsunesada, Yoshiki; Udo, Shigeharu; Wiencke, Lawrence R.

    2012-07-01

    We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser beam. The experimental setup, measurement procedure, and results of calibration are described. The total systematic uncertainty of the calibration is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the transport of the calibrated PMTs from the laboratory to the TA experimental site.

  13. Study on neutron scattering in light water

    NASA Astrophysics Data System (ADS)

    Scotta, Juan Pablo; Marquez Damian, Ignacio; Noguere, Gilles; Bernard, David

    2016-03-01

    It is presented a method to produce covariance matrices of the light water total cross section from thermal scattering laws of the JEFF-3.1.1 nuclear data library and CAB model. The generalized least square method was used to fit the LEAPR module parameters of the processing tool NJOY with light water experimental transmission measurements at 293.6K with CONRAD code. The marginalization technique was applied to account for systematic uncertainties.

  14. The whiteness of things and light scattering

    NASA Astrophysics Data System (ADS)

    Gratton, L. M.; López-Arias, T.; Calzà, G.; Oss, S.

    2009-07-01

    We discuss some simple experiments dealing with intriguing properties of light and its interaction with matter. In particular, we show how to emphasize that light reflection, refraction and scattering can provide a proper, physical description of human perception of the 'colour' white. These experiments can be used in the classroom with an enquiry approach, and it is in this spirit that we will present them.

  15. Light scattering by a reentrant fractal surface.

    PubMed

    Mendoza-Suárez, A; Méndez, E R

    1997-05-20

    Recently, rigorous numerical techniques for treating light scattering problems with one-dimensional rough surfaces have been developed. In their usual formulation, these techniques are based on the solution of two coupled integral equations and are applicable only to surfaces whose profiles can be described by single-valued functions of a coordinate in the mean plane of the surface. In this paper we extend the applicability of the integral equation method to surfaces with multivalued profiles. A procedure for finding a parametric description of a given profile is described, and the scattering equations are established within the framework of this formalism. We then present some results of light scattering from a sequence of one-dimensional flat surfaces with defects in the form of triadic Koch curves. Beyond a certain order of the prefractal, the scattering patterns become stationary (within the numerical accuracy of the method). It can then be argued that the results obtained correspond to a surface with a fractal structure. These constitute, to our knowledge, the first rigorous calculations of light scattering from a reentrant fractal surface. PMID:18253371

  16. High-power single-mode laser operation using stimulated Rayleigh scattering

    SciTech Connect

    Denariez-Roberge, M.M.; Giuliani, G.

    1981-07-01

    We report single-mode high-power Nd:YAG laser operation by stimulated thermal Rayleigh Q switching. We also analyze the phase-conjugation properties of collinear four-wave mixing that is due to low-frequency excitations in absorbing liquids.

  17. Light scattering by randomly oriented crystals

    NASA Astrophysics Data System (ADS)

    Muinonen, Karri; Lumme, Kari; Peltoniemi, Jouni; Irvine, William M.

    The scattering phase function and the degree of linear polarization for small crystals oriented randomly in space have been computed using the geometric ray tracing theory and assuming that the crystals are homogeneous and isotropic. Calculations have been carried out for the main crystal geometries. Detection of halos from crystals other than hexagonal water ice is briefly discussed. The crystal size and shape parameters have also been averaged over some simple distributions in order to examine general light scattering properties of sharp-edged particles. A scalar physical optics correction has been developed for the geometric optics phase functions. Results can be applied to light scattering from regoliths and planetary rings, and possibly also to atmospheric halos. Retroreflecting crystals in the regolith would cause an opposition spike, a phenomenon observed for many bright satellites.

  18. Light scattering by randomly oriented crystals

    NASA Technical Reports Server (NTRS)

    Muinonen, Karri; Lumme, Kari; Peltoniemi, Jouni; Irvine, William M.

    1989-01-01

    The scattering phase function and the degree of linear polarization for small crystals oriented randomly in space have been computed using the geometric ray tracing theory and assuming that the crystals are homogeneous and isotropic. Calculations have been carried out for the main crystal geometries. Detection of halos from crystals other than hexagonal water ice is briefly discussed. The crystal size and shape parameters have also been averaged over some simple distributions in order to examine general light scattering properties of sharp-edged particles. A scalar physical optics correction has been developed for the geometric optics phase functions. Results can be applied to light scattering from regoliths and planetary rings, and possibly also to atmospheric halos. Retroreflecting crystals in the regolith would cause an opposition spike, a phenomenon observed for many bright satellites.

  19. Light scattering from diatomaceous earth aerosol

    NASA Astrophysics Data System (ADS)

    Alexander, Jennifer M.; Meland, B.; Laskina, Olga; Young, M. A.; Grassian, V. H.; Kleiber, P. D.

    2013-08-01

    The light scattering and extinction properties of mineral aerosol are strongly affected by dust particle shape. In this work, scattering phase function and polarization profiles of diatomaceous earth aerosol are measured at a wavelength of 550 nm, and the results are compared to T-matrix theory based simulations using uniform spheroid models for the particle shape. The particle shape distribution is determined by spectral fitting of the experimental infrared (IR) extinction spectral line profile for diatomaceous earth dust. It is found that a particle shape model that peaks toward both extreme rod-like and disk-like shapes results in the best fits to the IR spectral data. This particle shape model is then used as a basis for modeling the visible light scattering properties. While the visible simulations show only modestly good agreement with the data, the fits are generally better than those obtained using more commonly invoked particle shape distributions.

  20. Immunoassay control method based on light scattering

    NASA Astrophysics Data System (ADS)

    Bilyi, Olexander I.; Kiselyov, Eugene M.; Petrina, R. O.; Ferensovich, Yaroslav P.; Yaremyk, Roman Y.

    1999-11-01

    The physics principle of registration immune reaction by light scattering methods is concerned. The operation of laser nephelometry for measuring antigen-antibody reaction is described. The technique of obtaining diagnostic and immune reactions of interaction latex agglutination for diphtheria determination is described.

  1. Measurement of the depolarization ratio of Rayleigh scattering at absorption bands

    NASA Astrophysics Data System (ADS)

    Anglister, J.; Steinberg, I. Z.

    1981-01-01

    Measurements of the depolarization ratio ρv of light scattered by the pigments lycopene and β-carotene at the red part of their absorption bands yielded values which are very close to the theoretical value 1/3 of a fully anisotropic molecular polarizability, i.e., that due to an electric dipole moment. Measurements of ρv at the blue edge of the visible absorption band of pinacyanol chloride yielded a value of 0.75 at 472.2 nm, which is the maximum value that a depolarization ratio can assume, and is attained if the average molecular polarizability is zero. This is possible only if the diagonalized polarizability tensor has at least one negative element to counterbalance the positive ones. A negative refractive index at the blue edge of the absorption band is thus experimentally demonstrated.

  2. Investigating the interaction of crystal violet probe molecules on sodium dodecyl sulfate micelles with hyper-Rayleigh scattering.

    PubMed

    Revillod, Guillaume; Russier-Antoine, Isabelle; Benichou, Emmanuel; Jonin, Christian; Brevet, Pierre-François

    2005-03-24

    We report the use of the nonlinear optical technique of hyper-Rayleigh scattering to investigate the interaction of the cationic probe molecule crystal violet with micelles of sodium dodecyl sulfate. An absolute value of (847 +/- 80) x 10(-30) esu is measured at the fundamental wavelength of 870 nm for the molecular hyperpolarizability of crystal violet free in pure aqueous solutions. In aqueous solutions of sodium dodecyl sulfate, above and below the critical micelle concentration, the measured hyperpolarizability of crystal violet is weaker than in the solution free of sodium dodecyl sulfate. From the comparison with linear optical photoabsorption spectroscopy data, this difference is attributed to electrostatic interactions between the cationic crystal violet molecules and the negatively charged sodium dodecyl sulfate surfactant molecules present in excess. Polarization resolved hyper-Rayleigh scattering measurements are then performed to show that, below and above the critical micelle concentration, crystal violet molecules also undergo symmetry changes upon interaction with sodium dodecyl sulfate. Above the critical micelle concentration, the minimum fraction of micelles interacting with at least one CV molecule is estimated. For instance, for a crystal violet aqueous concentration of 150 microM, this fraction is larger than 7%. PMID:16863205

  3. The Measurement of Tropospheric Temperature Profiles using Rayleigh-Brillouin Scattering: Results from Laboratory and Atmospheric Studies

    NASA Astrophysics Data System (ADS)

    Witschas, Benjamin; Reitebuch, Oliver; Lemmerz, Christian; Gomez Kableka, Pau; Kondratyev, Sergey; Gu, Ziyu; Ubachs, Wim

    2016-06-01

    In this letter, we suggest a new method for measuring tropospheric temperature profiles using Rayleigh-Brillouin (RB) scattering. We report on laboratory RB scattering measurements in air, demonstrating that temperature can be retrieved from RB spectra with an absolute accuracy of better than 2 K. In addition, we show temperature profiles from 2 km to 15.3 km derived from RB spectra, measured with a high spectral resolution lidar during daytime. A comparison with radiosonde temperature measurements shows reasonable agreement. In cloud-free conditions, the temperature difference reaches up to 5 K within the boundary layer, and is smaller than 2.5 K above. The statistical error of the derived temperatures is between 0.15 K and 1.5 K.

  4. Refinement of the Compton-Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer: II - Extraction of invisible element content

    NASA Astrophysics Data System (ADS)

    Perrett, Glynis M.; Campbell, John L.; Gellert, Ralf; King, Penelope L.; Nield, Emily; O'Meara, Joanne M.; Pradler, Irina

    2016-02-01

    The intensity ratio C/R between Compton and Rayleigh scatter peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα scatter peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as 'unknowns' in order to evaluate the accuracy of ALIC concentrations derived in this manner.

  5. Scattered light in the STIS echelle modes

    NASA Technical Reports Server (NTRS)

    Landsman, W.; Bowers, C.

    1997-01-01

    The Space Telescope Imaging Spectrograph (STIS) echelle spectra obtained during the Early Release Observations have non-zero residuals in the cores of saturated interstellar lines, indicating the need for a scattered light correction. A rough measure of the magnitude of the needed correction shows the ratio of the interorder to the in-order flux in different echelle modes in both pre-launch calibration images of a continuum lamp source and in post-launch images of stellar continuum sources. The interorder and in-order fluxes are computed by averaging the central 200 pixels in the dispersion direction. The amount of scattered light in the interorder region rises toward shorter wavelengths for two reasons: (1) the order separation decreases toward shorter wavelengths; and (2) the amount of echelle scattering is expected to have an inverse dependence on wavelength. At the shortest wavelengths the fraction of light scattered into the interorder region can be 10% for the Near-ultraviolet-Multi-Anode Microchannel Array (NUV-MAMA) and 15% for the Far-ultraviolet-Multi-Anode Microchannel Array (FUV-MAMA).

  6. Dynamic Light Scattering From Colloidal Gels

    NASA Technical Reports Server (NTRS)

    Krall, A. H.; Weitz, David A.

    1996-01-01

    We present a brief, preliminary account of the interpretation of dynamic light scattering from fractal colloidal gels. For small scattering angles, and for high initial colloid particle volume fractions, the correlation functions exhibit arrested decay, reflecting the non-ergodic nature of these systems and allowing us to directly determine the elastic modulus of the gels. For smaller initial volume fractions, the correlation functions decay completely. In all cases, the initial decay is not exponential, but is instead described by a stretched exponential. We summarize the principles of a model that accounts for these data and discuss the scaling behavior of the measured parameters.

  7. Multiple Light Scattering Probes of Soft Materials

    NASA Astrophysics Data System (ADS)

    Scheffold, Frank

    2007-02-01

    I will discuss both static and dynamic properties of diffuse waves. In practical applications the optical properties of colloidal systems play an important role, for example in commercial products such as sunscreen lotions, food (drinks), coatings but also in medicine for example in cataract formation (eye lens turbidity). It is thus of importance to know the key parameters governing optical turbidity from the single to the multiple scattering regime. Temporal fluctuations of multiply scattered light are studied with photon correlation spectroscopy (Diffusing Wave Spectroscopy). This DWS method and its various implementations will be treated.

  8. Light scattering by cirrus cloud layers.

    NASA Technical Reports Server (NTRS)

    Liou, K.-N.

    1972-01-01

    The properties of the reflection, transmission, and absorption of the cirrus cloud layers are calculated under the assumption that the ice crystals in cirrus clouds may be approximated long circular cylinders randomly oriented in space. The phase function, the single scattering albedo, and the extinction cross section are obtained on the basis of Liou's (1972) calculations of light scattering by ice clouds in the visible and infrared. A modified two-stream approximation for radiative transfer is developed and is used to evaluate the radiative properties of the cirrus cloud layers.

  9. Scattering of dark particles with light mediators

    NASA Astrophysics Data System (ADS)

    Soper, Davison E.; Spannowsky, Michael; Wallace, Chris J.; Tait, Tim M. P.

    2014-12-01

    We present a treatment of the high energy scattering of dark Dirac fermions from nuclei, mediated by the exchange of a light vector boson. The dark fermions are produced by proton-nucleus interactions in a fixed target and, after traversing shielding that screens out strongly interacting products, appear similarly to neutrino neutral current scattering in a detector. Using the Fermilab experiment E613 as an example, we place limits on a secluded dark matter scenario. Visible scattering in the detector includes both the familiar regime of large momentum transfer to the nucleus (Q2) described by deeply inelastic scattering, as well as small Q2 kinematics described by the exchanged vector mediator fluctuating into a quark-antiquark pair whose interaction with the nucleus is described by a saturation model. We find that the improved description of the low Q2 scattering leads to important corrections, resulting in more robust constraints in a regime where a description entirely in terms of deeply inelastic scattering cannot be trusted.

  10. Study on the ternary mixed ligand complex of palladium(II)-aminophylline-fluorescein sodium by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum and its analytical application.

    PubMed

    Chen, Peili; Liu, Shaopu; Liu, Zhongfang; Hu, Xiaoli

    2011-01-01

    The interaction between palladium(II)-aminophylline and fluorescein sodium was investigated by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum. In pH 4.4 Britton-Robinson (BR) buffer medium, aminophylline (Ami) reacted with palladium(II) to form chelate cation([Pd(Ami)]2+), which further reacted with fluorescein sodium (FS) to form ternary mixed ligand complex [Pd(Ami)(FS)2]. As a result, resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering spectrum (FDS) were enhanced. The maximum scattering wavelengths of [Pd(Ami)(FS)2] were located at 300 nm (RRS), 650 nm (SOS) and 304 nm (FDS). The scattering intensities were proportional to the Ami concentration in a certain range and the detection limits were 7.3 ng mL(-1) (RRS), 32.9 ng mL(-1) (SOS) and 79.1 ng mL(-1) (FDS), respectively. Based on it, the new simple, rapid, and sensitive scattering methods have been proposed to determine Ami in urine and serum samples. Moreover, the formation mechanism of [Pd(Ami)(FS)2] and the reasons for enhancement of RRS were fully discussed. PMID:21163688

  11. A high-power spatial filter for Thomson scattering stray light reduction

    NASA Astrophysics Data System (ADS)

    Levesque, J. P.; Litzner, K. D.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.

    2011-03-01

    The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

  12. A high-power spatial filter for Thomson scattering stray light reduction

    SciTech Connect

    Levesque, J. P.; Litzner, K. D.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.

    2011-03-15

    The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

  13. Atmospheric particulate analysis using angular light scattering

    NASA Technical Reports Server (NTRS)

    Hansen, M. Z.

    1980-01-01

    Using the light scattering matrix elements measured by a polar nephelometer, a procedure for estimating the characteristics of atmospheric particulates was developed. A theoretical library data set of scattering matrices derived from Mie theory was tabulated for a range of values of the size parameter and refractive index typical of atmospheric particles. Integration over the size parameter yielded the scattering matrix elements for a variety of hypothesized particulate size distributions. A least squares curve fitting technique was used to find a best fit from the library data for the experimental measurements. This was used as a first guess for a nonlinear iterative inversion of the size distributions. A real index of 1.50 and an imaginary index of -0.005 are representative of the smoothed inversion results for the near ground level atmospheric aerosol in Tucson.

  14. Laser light scattering in eye lens model

    NASA Astrophysics Data System (ADS)

    Larionova, Nadezhda L.; Maksimova, Irina L.; Kochubey, Vyacheslav I.

    2000-11-01

    Theoretical investigations of laser light radiation scattered by eye lens model as a system of spheres with various parameters were performed on the base of Mie theory of electromagnetic scattering by a single sphere. The calculations were performed for systems of particles whose coordinates were specifically realized in random fashion according to the specified probabilities defined by the approximation of hard spheres. The modeling of lens biotissue was carried out by using of medical data about internal structure of lens of human and some animals. In general the researchable model presents the system of homogeneous spherical particles those are randomly distributed in the layer of thickness. We study the optical properties such as scattering effective cross-section and function of correlation in different models.

  15. Laser Light Scattering by Shock Waves

    NASA Technical Reports Server (NTRS)

    Panda, J.; Adamovsky, G.

    1995-01-01

    Scattering of coherent light as it propagates parallel to a shock wave, formed in front of a bluff cylindrical body placed in a supersonic stream, is studied experimentally and numerically. Two incident optical fields are considered. First, a large diameter collimated beam is allowed to pass through the shock containing flow. The light intensity distribution in the resultant shadowgraph image, measured by a low light CCD camera, shows well-defined fringes upstream and downstream of the shadow cast by the shock. In the second situation, a narrow laser beam is brought to a grazing incidence on the shock and the scattered light, which appears as a diverging sheet from the point of interaction, is visualized and measured on a screen placed normal to the laser path. Experiments are conducted on shocks formed at various free-stream Mach numbers, M, and total pressures, P(sub 0). It is found that the widths of the shock shadows in a shadowgraph image become independent of M and P(sub 0) when plotted against the jump in the refractive index, (Delta)n, created across the shock. The total scattered light measured from the narrow laser beam and shock interaction also follows the same trend. In the numerical part of the study, the shock is assumed to be a 'phase object', which introduces phase difference between the upstream and downstream propagating parts of the light disturbances. For a given shape and (Delta)n of the bow shock the phase and amplitude modulations are first calculated by ray tracing. The wave front is then propagated to the screen using the Fresnet diffraction equation. The calculated intensity distribution, for both of the incident optical fields, shows good agreement with the experimental data.

  16. The fluorescence and resonance Rayleigh scattering spectral study and analytical application of cerium (IV) and cefoperazone system

    NASA Astrophysics Data System (ADS)

    Yuan, Yusheng; Fu, Shenghui; Xu, Qianying; Yang, Jidong; Hu, Xiaoli; Liu, Shaopu

    2016-06-01

    In weak acidic medium of pH 3.5-5.6, Ce(IV) can be reduced by cefoperazone (CPZ) to be Ce(III), which further combined with CPZ to form complex Ce(OH)3CPZ. This complex not only has higher fluorescence than Ce(III), but also results in significant increase of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequency doubling scattering (FDS). The wavelengths of maximum fluorescence exciting and emission are located at 356 nm/349 nm, while the maximum wavelengths of RRS, SOS and FDS are at 312 nm, 550 nm and 390 nm, respectively. The intensity of fluorescence and scattering are all linear with the concentration of CPZ in certain conditions. The detection limit of most sensitive RRS method for CPZ is 2.1 ng mL- 1. The optimum conditions for detecting CPZ using RRS method are investigated. The effect of co-existing substances shows that the method has excellent selectivity, especially since other cephalosporins don't have similar reactions. Therefore, it can be achieved to determine CPZ in cephalosporins selectively. The paper also focuses on the reaction mechanism, the consistent and contracture of the resultant. The reasons for enhanced intensity are presumed in the meantime.

  17. The fluorescence and resonance Rayleigh scattering spectral study and analytical application of cerium (IV) and cefoperazone system.

    PubMed

    Yuan, Yusheng; Fu, Shenghui; Xu, Qianying; Yang, Jidong; Hu, Xiaoli; Liu, Shaopu

    2016-06-01

    In weak acidic medium of pH3.5-5.6, Ce(IV) can be reduced by cefoperazone (CPZ) to be Ce(III), which further combined with CPZ to form complex Ce(OH)3CPZ. This complex not only has higher fluorescence than Ce(III), but also results in significant increase of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequency doubling scattering (FDS). The wavelengths of maximum fluorescence exciting and emission are located at 356 nm/349 nm, while the maximum wavelengths of RRS, SOS and FDS are at 312 nm, 550 nm and 390 nm, respectively. The intensity of fluorescence and scattering are all linear with the concentration of CPZ in certain conditions. The detection limit of most sensitive RRS method for CPZ is 2.1 ng mL(-1). The optimum conditions for detecting CPZ using RRS method are investigated. The effect of co-existing substances shows that the method has excellent selectivity, especially since other cephalosporins don't have similar reactions. Therefore, it can be achieved to determine CPZ in cephalosporins selectively. The paper also focuses on the reaction mechanism, the consistent and contracture of the resultant. The reasons for enhanced intensity are presumed in the meantime. PMID:26994317

  18. Light scattering measurement of sodium polyacrylate products

    NASA Astrophysics Data System (ADS)

    Lama, Nisha; Norwood, David; Boone, Steven; Massie-Boyer, Valerie

    2015-03-01

    In the presentation, we will describe the use of a multi-detector HPLC incorporating the DAWN EOS multi-angle laser light scattering (MALLS) detector to measure the properties such as molecular weight, RMS radius, contour and persistence length and polydispersity of sodium polyacrylate products. The samples of sodium polyacrylate are used in various industries as thickening agents, coating dispersants, artificial snow, laundry detergent and disposable diapers. Data and results obtained from the experiment will be presented.

  19. Accuracy of RGD approximation for computing light scattering properties of diffusing and motile bacteria.

    PubMed

    Kotlarchyk, M; Chen, S H; Asano, S

    1979-07-15

    The quasi-elastic light scattering has become an established technique for a rapid and quantitative characterization of an average motility pattern of motile bacteria in suspensions. Essentially all interpretations of the measured light scattering intensities and spectra so far are based on the Rayleigh-Gans-Debye (RGD) approximation. Since the range of sizes of bacteria of interest is generally larger than the wavelength of light used in the measurement, one is not certain of the justification for the use of the RGD approximation. In this paper we formulate a method by which both the scattering intensity and the quasi-elastic light scattering spectra can be calculated from a rigorous scattering theory. For a specific application we study the case of bacteria Escherichia coli (about 1 microm in size) by using numerical solutions of the scattering field amplitudes from a prolate spheroid, which is known to simulate optical properties of the bacteria well. We have computed (1) polarized scattered light intensity vs scattering angle for a randomly oriented bacteria population; (2) polarized scattered field correlation functions for both a freely diffusing bacterium and for a bacterium undergoing a straight line motion in random directions and with a Maxwellian speed distribution; and (3) the corresponding depolarized scattered intensity and field correlation functions. In each case sensitivity of the result to variations of the index of refraction and size of the bacterium is investigated. The conclusion is that within a reasonable range of parameters applicable to E. coli, the accuracy of the RGD is good to within 10% at all angles for the properties (1) and (2), and the depolarized contributions in (3) are generally very small. PMID:20212685

  20. Q-space analysis of light scattering by Gaussian Random Spheres

    NASA Astrophysics Data System (ADS)

    Maughan, Justin B.; Sorensen, Christopher M.; Chakrabarti, Amitabha

    2016-05-01

    Q-space analysis is applied to the scattered intensity from Gaussian Random Spheres (GRSs). Q-space analysis involves plotting the scattered intensity vs. the magnitude of the scattering wave vector q = 2 k sin θ/2 where k = 2 π / λ with λ the wavelength and θ is the scattering angle, on a log-log plot. The light scattering properties of GRSs were calculated using a discrete dipole approximation algorithm. The GRSs had σ=0.2 and ν=3, where σ is the relative standard deviation in the radial direction, and ν describes fluctuations in the angular direction. Calculations were systematically performed with size parameters ranging from 10 to 30, and with a relative index of refraction, m, ranging from 1.01 to 1.5. The results show quantifiable, power law descriptions of the scattered intensity and a Rayleigh functionality of the forward scattered intensity that depend upon the phase shift parameter ρ = 2 k Req | m - 1 | where Req is an equivalent radius. Similar functionalities have been observed in both spheres and other irregularly shaped particles. These results continue the implication that there is a comprehensive description of light scattering for all particles that can be uncovered with the application of Q-space.

  1. Planar Rayleigh scattering and laser-induced fluorescence for visualization of a hot, Mach 2 annular air jet

    NASA Astrophysics Data System (ADS)

    Balla, R. Jeffrey

    1994-10-01

    Planar Rayleigh scattering (PRS) and planar laser-induced fluorescence (PLIF) were used to investigate the vitiated air component of a coaxial hydrogen/vitiated air nonpremixed turbulent jet flame that is ejected at a Mach number of 2. All experiments were performed with a xenon chloride tunable excimer laser. Planar information for both techniques was obtained using laser sheets 6 cm high, 5 cm wide, and 300 micron thick. In this flow field, the effective Rayleigh cross section of the components in the vitiated air was assumed to be independent of composition. Therefore, the PRS technique produced signals which were proportional to total density. When the flow field was assumed to be at a known and uniform pressure, the PRS signal data for the vitiated air could be converted to temperature information. Also, PLIF images were generated by probing the OH molecule. These images contain striation patterns attributed to small localized instantaneous temperature nonuniformities. The results from the PLIF and PRS techniques were used to show that this flow field contains a nongaseous component, most likely liquid water that can be reduced by increasing the settling chamber wall temperature.

  2. Planar Rayleigh scattering and laser-induced fluorescence for visualization of a hot, Mach 2 annular air jet

    NASA Technical Reports Server (NTRS)

    Balla, R. Jeffrey

    1994-01-01

    Planar Rayleigh scattering (PRS) and planar laser-induced fluorescence (PLIF) were used to investigate the vitiated air component of a coaxial hydrogen/vitiated air nonpremixed turbulent jet flame that is ejected at a Mach number of 2. All experiments were performed with a xenon chloride tunable excimer laser. Planar information for both techniques was obtained using laser sheets 6 cm high, 5 cm wide, and 300 micron thick. In this flow field, the effective Rayleigh cross section of the components in the vitiated air was assumed to be independent of composition. Therefore, the PRS technique produced signals which were proportional to total density. When the flow field was assumed to be at a known and uniform pressure, the PRS signal data for the vitiated air could be converted to temperature information. Also, PLIF images were generated by probing the OH molecule. These images contain striation patterns attributed to small localized instantaneous temperature nonuniformities. The results from the PLIF and PRS techniques were used to show that this flow field contains a nongaseous component, most likely liquid water that can be reduced by increasing the settling chamber wall temperature.

  3. Bacterial Identification Using Light Scattering Measurements: a Preliminary Report

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.

    1971-01-01

    The light scattering properties of single bacterial cells were examined as a possible means of identification. Three species were studied with streptococcus faecalis exhibiting a unique pattern; the light-scattering traces for staphylococcus aureus and escherichia coli were quite similar although differences existed. Based on preliminary investigations, the light scattering approach appeared promising with additional research needed to include a wide variety of bacterial species, computer capability to handle and analyze data, and expansion of light scattering theory to include bacterial cells.

  4. Improved Optics For Quasi-Elastic Light Scattering

    NASA Technical Reports Server (NTRS)

    Cheung, Harry Michael

    1995-01-01

    Improved optical train devised for use in light-scattering measurements of quasi-elastic light scattering (QELS) and laser spectroscopy. Measurements performed on solutions, microemulsions, micellular solutions, and colloidal dispersions. Simultaneous measurements of total intensity and fluctuations in total intensity of light scattered from sample at various angles provides data used, in conjunction with diffusion coefficients, to compute sizes of particles in sample.

  5. Study on erythrosine-phen-Cd(II) systems by resonance Rayleigh scattering, absorption spectra and their analytical applications

    NASA Astrophysics Data System (ADS)

    Tian, Jing; Zhang, Qiqi; Liu, Shaopu; Yang, Jidong; Teng, Ping; Zhu, Jinghui; Qiao, Man; Shi, Ying; Duan, Ruilin; Hu, Xiaoli

    2015-04-01

    In pH 7.0-8.0 KH2PO4-Na2HPO4 buffer solution, Cd(II) reacted with 1,10-phenanthroline to form chelate cation [Cd(phen)3]2+, which further reacted with anion of erythrosine to form ternary ion-association complex through electrostatic attraction and hydrophobic effect. This process could result in remarkable absorption spectra change and produce obvious fading reaction at 528 nm. Absorbance change (ΔA) of system was directly proportional to the concentration of Cd(II). Hereby, a highly sensitive spectrophotometric method for the determination of Cd(II) was established. The molar absorption coefficient was 2.29 × 105 L mol-1 cm-1 and the detection limit of Cd(II) was 26.5 ng mL-1. Furthermore, the resonance Rayleigh scattering (RRS) of this system with two peaks located at 371 and 590 nm enhanced significantly, and second-order scattering (SOS) and frequence doubling scattering (FDS) of this system changed notably at 640 and 350 nm, respectively. Under the optimum conditions, the scattering intensities (ΔIRRS, ΔIDWO-RRS, ΔISOS and ΔIFDS) had good linear relationship with the concentration of Cd(II) in certain ranges. The detection limits of Cd(II) were 1.27 ng mL-1, 1.39 ng mL-1, 4.03 ng mL-1, 5.92 ng mL-1 and 14.7 ng mL-1 for dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS), RRS (371 nm), RRS (590 nm), SOS and FDS, respectively. In addition, the suitable reaction conditions and effects of coexisting substances were investigated. The methods had been successfully applied to the determination of Cd(II) in environmental water samples. The recovery range was between 93.0% and 103.0% and the relative standard deviation (RSD) was between 2.5% and 4.3%. The results were in agreement with those obtained from atomic absorption spectroscopy.

  6. Daytime measurements of atmospheric temperature profiles (2-15 km) by lidar utilizing Rayleigh-Brillouin scattering.

    PubMed

    Witschas, Benjamin; Lemmerz, Christian; Reitebuch, Oliver

    2014-04-01

    In this Letter, we report on a novel method for measuring atmospheric temperature profiles by lidar during daytime for heights of 2-15.3 km, with a vertical resolution of 0.3-2.2 km, using Rayleigh-Brillouin scattering. The measurements are performed by scanning a laser (λ=355 nm) over a 12 GHz range and using a Fabry-Pérot interferometer as discriminator. The temperature is derived by using a new analytical line shape model assuming standard atmospheric pressure conditions. Two exemplary temperature profiles resulting from measurements over 14 and 27 min are shown. A comparison with radiosonde temperature measurements shows reasonable agreement. In cloud-free conditions, the temperature difference reaches up to 5 K within the boundary layer, and is smaller than 2.5 K above. The statistical error of the derived temperatures is between 0.15 and 1.5 K. PMID:24686652

  7. A sensitive and selective resonance Rayleigh scattering method for quick detection of avidin using affinity labeling Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Huang, Xi; Fu, Xuan; Deng, Huan; Ma, Meihu; Cai, Zhaoxia

    2016-06-01

    Avidin is a glycoprotein with antinutritional property, which should be limited in daily food. We developed an affinity biosensor system based on resonance Rayleigh scattering (RRS) and using affinity biotin labeling Au nanoparticles (AuNPs). This method was selective and sensitive for quick avidin detection due to the avidin-biotin affinitive interaction. Under optimal conditions, RRS intensity of biotin-AuNPs increase linearly with an increasing concentration of avidin from 5 to 160 ng/mL. The lower limit of detection was 0.59 ng/mL. This rapid and selective avidin detection method was used in synthetic samples and egg products with recoveries of between 102.97 and 107.92%, thereby demonstrating the feasible and practical application of this assay.

  8. Simultaneous measurement of electron and heavy particle temperatures in He laser-induced plasma by Thomson and Rayleigh scattering

    SciTech Connect

    Dzierzega, K.; Mendys, A.; Zawadzki, W.; Pokrzywka, B.; Pellerin, S.

    2013-04-01

    Thomson and Rayleigh scattering methods were applied to quantify the electron and heavy particle temperatures, as well as electron number density, in a laser spark in helium at atmospheric pressure. Plasma was created using 4.5 ns, 25 mJ pulses from Nd:YAG laser at 532 nm. Measurements, performed for the time interval between 20 ns and 800 ns after breakdown, show electron density and temperature to decrease from 7.8 Multiplication-Sign 10{sup 23} m{sup -3} to 2.6 Multiplication-Sign 10{sup 22} m{sup -3} and from 95 900 K to 10 350 K, respectively. At the same time, the heavy particle temperature drops from only 47 000 K down to 4100 K which indicates a two temperature plasma out of local isothermal equilibrium.

  9. A sensitive and selective resonance Rayleigh scattering method for quick detection of avidin using affinity labeling Au nanoparticles.

    PubMed

    Wang, Qi; Huang, Xi; Fu, Xuan; Deng, Huan; Ma, Meihu; Cai, Zhaoxia

    2016-06-01

    Avidin is a glycoprotein with antinutritional property, which should be limited in daily food. We developed an affinity biosensor system based on resonance Rayleigh scattering (RRS) and using affinity biotin labeling Au nanoparticles (AuNPs). This method was selective and sensitive for quick avidin detection due to the avidin-biotin affinitive interaction. Under optimal conditions, RRS intensity of biotin-AuNPs increase linearly with an increasing concentration of avidin from 5 to 160ng/mL. The lower limit of detection was 0.59ng/mL. This rapid and selective avidin detection method was used in synthetic samples and egg products with recoveries of between 102.97 and 107.92%, thereby demonstrating the feasible and practical application of this assay. PMID:26978788

  10. Modeling light scattering from diesel soot particles

    SciTech Connect

    Hull, Patricia; Shepherd, Ian; Hunt, Arlon

    2002-07-16

    The Mie model is widely used to analyze light scattering from particulate aerosols. The Diesel Particle Scatterometer (DPS), for example, determines the size and optical properties of diesel exhaust particles that are characterized by measuring three angle-dependent elements of the Mueller scattering matrix. These elements are then fitted using Mie calculations with a Levenburg-Marquardt optimization program. This approach has achieved good fits for most experimental data. However, in many cases, the predicted real and imaginary parts of the index of refraction were less than that for solid carbon. To understand this result and explain the experimental data, we present an assessment of the Mie model by use of a light scattering model based on the coupled dipole approximation. The results indicate that the Mie calculation can be used to determine the largest dimension of irregularly shaped particles at sizes characteristic of Diesel soot and, for particles of known refractive index, tables can be constructed to determine the average porosity of the particles from the predicted index of refraction.

  11. The new IAA Light Scattering Facility

    NASA Astrophysics Data System (ADS)

    Muñoz, O.; Moreno, F.; Molina, A.; Guirado, D.; Ramos, J. L.; López, A.; Girela, F.; Costillo, L. P.

    2005-05-01

    We are building up a light scattering setup at the Instituto de Astrofísica de Andalucía (IAA), Granada, Spain. The design of this new setup is based on the well known apparatus currently located at the Astronomical Institute "Anton Pannekoek", University of Amsterdam, The Neteherlands [1],[2]. By using a polarization modulation technique, all scattering matrix elements as function of the scattering angle are obtained from 8 separate measurement runs. In this new setup we use an Argon-Kripton laser (483 nm, 488 nm, 514 nm, 568 nm, and 647 nm) as light source. The detectors are mounted on dove tails that allow their movement backward and forward. In addition, the detectors have been designed to minimize blockage of the laser beam at positions close to the forward and backward directions. In this way we intend to do measurements covering an angle range from 3 to 177 degrees. The alignment of the optics is automatically done and controlled from the computer reducing the measurement time.

  12. Resonance Rayleigh scattering study on the interaction of gold nanoparticles with berberine hydrochloride and its analytical application.

    PubMed

    Liu, Shao Pu; Yang, Zhuo; Liu, Zhong Fang; Liu, Jiang Tao; Shi, Yan

    2006-07-21

    The interaction of gold nanoparticles with berberine hydrochloride has been studied by using resonance Rayleigh scattering (RRS) spectra. In pH 3.8-5.5 aqueous solution, citrate acid ([H2L2-]) self-assembled on the surface of positively charged gold nanoparticles (average diameter is about 12.0 nm) to form a supermolecular complex with negative charges. By virtue of electrostatic attraction, hydrophobic force and charge transfer, the complex bound with berberine to form complex, which had bigger diameter (35 nm) than gold nanoparticles. The formation of the binding production not only resulted in the red shift of absorption of gold nanoparticles from 518 to 672 nm, but also led to the greatly enhancement of RRS intensity. At the same time, the intensities of second-order scattering (SOS) and frequency-doubling scattering (FDS) were also increased. Under definite condition, the increment of the RRS (DeltaI) were proportional to the concentration of berberine. A sensitive and simple method for the determination of berberine based on the RRS technique has been developed. The detection limit (3sigma) for berberine was 0.40 ng mL(-1) and the quantitative determination range was 1.33-240 ng mL(-1). In this work, the optimum conditions of reaction, the effect of foreign substances and the analytical application had been investigated. PMID:17723490

  13. Measurement of light scattering in deep sea

    NASA Astrophysics Data System (ADS)

    Maragos, N.; Balasi, K.; Domvoglou, T.; Kiskiras, I.; Lenis, D.; Maniatis, M.; Stavropoulos, G.

    2016-04-01

    The deep-sea neutrino telescope in the Mediterranean Sea, being prepared by the KM3NET collaboration, will contain thousands of optical sensors to readout. The accurate knowledge of the optical properties of deep-sea water is of great importance for the neutrino event reconstruction process. In this study we describe our progress in designing an experimental setup and studying a method to measure the parameters describing the absorption and scattering characteristics of deep-sea water. Three PMTs will be used to measure in situ the scattered light emitted from six laser diodes in three different wavelengths covering the Cherenkov radiation spectrum. The technique for the evaluation of the parameters is based on Monte Carlo simulations and our results show that we are able to determine these parameters with satisfying precision.

  14. Distributed Temperature and Strain Discrimination with Stimulated Brillouin Scattering and Rayleigh Backscatter in an Optical Fiber

    PubMed Central

    Zhou, Da-Peng; Li, Wenhai; Chen, Liang; Bao, Xiaoyi

    2013-01-01

    A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF) with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA) with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR). These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved. PMID:23385406

  15. Light scattering from dense cold atomic media

    NASA Astrophysics Data System (ADS)

    Zhu, Bihui; Cooper, John; Ye, Jun; Rey, Ana Maria

    2016-08-01

    We theoretically study the propagation of light through a cold atomic medium, where the effects of motion, laser intensity, atomic density, and polarization can all modify the properties of the scattered light. We present two different microscopic models: the "coherent dipole model" and the "random-walk model", both suitable for modeling recent experimental work done in large atomic arrays in the low-light-intensity regime. We use them to compute relevant observables such as the linewidth, peak intensity, and line center of the emitted light. We further develop generalized models that explicitly take into account atomic motion. Those are relevant for hotter atoms and beyond the low-intensity regime. We show that atomic motion can lead to drastic dephasing and to a reduction of collective effects, together with a distortion of the line shape. Our results are applicable to model a full gamut of quantum systems that rely on atom-light interactions, including atomic clocks, quantum simulators, and nanophotonic systems.

  16. Scattering of light from metamaterial gratings with finite length.

    PubMed

    Grünhut, Vivian; Cuevas, Mauro; Depine, Ricardo A

    2012-06-01

    Using an integral equation approach based on the Rayleigh hypothesis, we investigate the scattering of a plane wave at the rough surface of a metamaterial with a finite number of sinusoidal grooves. To show the adequacy of the model, we present results that are in agreement with the predictions of physical optics and that quantitatively reproduce the polarization and angular dependences predicted by the C-formalism for metamaterial gratings with an infinite number of grooves. PMID:22695585

  17. Independently Relaxing Nanoscale Inhomogeneities as model for Structural Relaxation: Light Scattering around the Glass Transition Region.

    NASA Astrophysics Data System (ADS)

    Lee, Mierie; Schroeder, John; Saha, Susanta K.; Moynihan, Cornelius T.

    1996-03-01

    Recent observations of anomalous light scattering (Rayleigh, Brillouin, and Raman) in the glass transition region indicate that the apparent distribution of structural relaxation times corresponds to a physical distribution of nanoscale inhomogeneities (density fluctuation) with varying properties. A modified version of the Tool-Narayanaswamy model incorporating this feature has been developed. Parameters obtained by fitting heat capacity heating curves with this model are found to give an excellent prediction of the anomalous light scattering of B_2O3 glass in the transition region. Other examples from Halide glasses will also be discussed. The measurement of Boson peaks in glasses and their interpretation with respect to density fluctuations is presented. The range and degree of disorder in a glass is obtained in a quantitative sense from the behavior of the spectral form of the Boson peaks with temperature.

  18. Atom-interferometric studies of light scattering

    SciTech Connect

    Beattie, S.; Barrett, B.; Chan, I.; Mok, C.; Kumarakrishnan, A.; Yavin, I.

    2009-07-15

    We have used an echo-type atom interferometer that manipulates laser-cooled atoms in a single ground state to investigate the effect of light scattering from pulsed and continuous-wave light. The interferometer uses two off-resonant standing-wave pulses applied at times t=0 and t=T to diffract and recombine momentum states separated by 2({Dirac_h}/2{pi})k at t=2T. Matter wave interference is associated with the formation of a density grating with period {lambda}/2 in the vicinity of this echo time. The grating contrast is measured by recording the intensity of coherently backscattered light. The interferometer is perturbed by an additional pulse applied at t=2T-{delta}T or by continuous-wave background light. If the additional pulse is a standing wave, the momentum states interfering at t=2T are displaced and the grating contrast can be completely recovered due to constructive interference. In this case, the contrast shows a periodic modulation at the atomic recoil frequency as a function of {delta}T. In a recent work, it was shown that the atomic recoil frequency can be measured easily and precisely when using coherence functions to model the signal shape. This paper provides an alternative description of the signal shape through an analytical calculation of echo formation in the presence of an additional standing-wave pulse. Using this treatment, it is possible to model the effects of spontaneous emission and spatial profile of the laser beam on the signal shape. Additionally, the theory predicts scaling laws as a function of the pulse area and the number of additional standing-wave pulses. These scaling laws are investigated experimentally and can be exploited to improve precision measurements of the atomic recoil frequency. We also show that coherence functions can be used to make a direct measurement of the populations of momentum states associated with the ground state under conditions where the Doppler-broadened velocity distribution of the sample is much

  19. Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Frisch, H.

    2010-11-01

    Context. The linear polarization of a strong resonance lines observed near the solar limb is created by a multiple-scattering process. Partial frequency redistribution (PRD) effects must be accounted for to explain the polarization profiles. The redistribution matrix describing the scattering process is a sum of terms, each containing a PRD function multiplied by a Rayleigh type phase matrix. A standard approximation made in calculating the polarization is to average the PRD functions over all the scattering angles, because the numerical work needed to take the angle-dependence of the PRD functions into account is large and not always needed for reasonable evaluations of the polarization. Aims: This paper describes a Stokes parameters decomposition method, that is applicable in plane-parallel cylindrically symmetrical media, which aims at simplifying the numerical work needed to overcome the angle-average approximation. Methods: The decomposition method relies on an azimuthal Fourier expansion of the PRD functions associated to a decomposition of the phase matrices in terms of the Landi Degl'Innocenti irreducible spherical tensors for polarimetry T^K_Q(i, Ω) (i Stokes parameter index, Ω ray direction). The terms that depend on the azimuth of the scattering angle are retained in the phase matrices. Results: It is shown that the Stokes parameters I and Q, which have the same cylindrical symmetry as the medium, can be expressed in terms of four cylindrically symmetrical components I_Q^K (K = Q = 0, K = 2, Q = 0, 1, 2). The components with Q = 1, 2 are created by the angular dependence of the PRD functions. They go to zero at disk center, ensuring that Stokes Q also goes to zero. Each component I_Q^K is a solution to a standard radiative transfer equation. The source term S_Q^K are significantly simpler than the source terms corresponding to I and Q. They satisfy a set of integral equations that can be solved by an accelerated lambda iteration (ALI) method.

  20. Highly sensitive determination of antimony in food by resonance Rayleigh scattering-energy transfer between grapheme oxide and I3(.).

    PubMed

    Wen, Guiqing; Zhang, Xinghui; Li, Yuan; Luo, Yanghe; Liang, Aihui; Jiang, Zhiliang

    2017-01-01

    Sb(III) was reduced to SbH3 gas and introduced to the I3(-)-grapheme oxide (GO) or I3(-)-silver nanorod (AgNR)-Victoria blue B (VBB) solutions. Resonance Rayleigh scattering energy transfer (RRS-ET) occurred between the donor GO and the acceptor I3(-) due to the overlap between the absorption peak of I3(-) and RRS peak of GO. When I3(-) was reduced by SbH3, RRS-ET weakened and the RRS intensity enhanced. The increased RRS intensity was linear to Sb concentration in the range of 2.1-376.6μg/L. In the I3(-)-AgNR-VBB solution, I3(-) combined with VBB to form VBB-I3 and there was a weak surface-enhanced Raman scattering (SERS) effect. When SbH3 reduced I3(-), the SERS intensity increased due to the release of SERS active VBB. The enhanced SERS intensity was linear for Sb concentration in the range of 8.4-292.9μg/L. The RRS-ET method was applied for determination of Sb in food with satisfactory results. PMID:27507443

  1. Double-wavelength overlapping resonance Rayleigh scattering technique for the simultaneous quantitative analysis of three β-adrenergic blockade.

    PubMed

    Tan, Xuanping; Yang, Jidong; Li, Qin; Yang, Qiong; Shen, Yizhong

    2016-05-15

    Four simple and accurate spectrophotometric methods were proposed for the simultaneous determination of three β-adrenergic blockade, e.g. atenolol, metoprolol and propranolol. The methods were based on the reaction of the three drugs with erythrosine B (EB) in a Britton-Robinson buffer solution at pH4.6. EB could combine with the drugs to form three ion-association complexes, which resulted in the resonance Rayleigh scattering (RRS) intensity that is enhanced significantly with new RRS peaks that appeared at 337nm and 370nm, respectively. In addition, the fluorescence intensity of EB was also quenched. The enhanced scattering intensities of the two peaks and the fluorescence quenched intensity of EB were proportional to the concentrations of the drugs, respectively. What is more, the RRS intensity overlapped with the double-wavelength of 337nm and 370nm (so short for DW-RRS) was also proportional to the drugs concentrations. So, a new method with highly sensitive for simultaneous determination of three bisoprolol drugs was established. Finally, the optimum reaction conditions, influencing factors and spectral enhanced mechanism were investigated. The new DW-RRS method has been applied to simultaneously detect the three β-blockers in fresh serum with satisfactory results. PMID:26926395

  2. Double-wavelength overlapping resonance Rayleigh scattering technique for the simultaneous quantitative analysis of three β-adrenergic blockade

    NASA Astrophysics Data System (ADS)

    Tan, Xuanping; Yang, Jidong; Li, Qin; Yang, Qiong; Shen, Yizhong

    2016-05-01

    Four simple and accurate spectrophotometric methods were proposed for the simultaneous determination of three β-adrenergic blockade, e.g. atenolol, metoprolol and propranolol. The methods were based on the reaction of the three drugs with erythrosine B (EB) in a Britton-Robinson buffer solution at pH 4.6. EB could combine with the drugs to form three ion-association complexes, which resulted in the resonance Rayleigh scattering (RRS) intensity that is enhanced significantly with new RRS peaks that appeared at 337 nm and 370 nm, respectively. In addition, the fluorescence intensity of EB was also quenched. The enhanced scattering intensities of the two peaks and the fluorescence quenched intensity of EB were proportional to the concentrations of the drugs, respectively. What is more, the RRS intensity overlapped with the double-wavelength of 337 nm and 370 nm (so short for DW-RRS) was also proportional to the drugs concentrations. So, a new method with highly sensitive for simultaneous determination of three bisoprolol drugs was established. Finally, the optimum reaction conditions, influencing factors and spectral enhanced mechanism were investigated. The new DW-RRS method has been applied to simultaneously detect the three β-blockers in fresh serum with satisfactory results.

  3. Quantitative fuel vapor/air mixing imaging in droplet/gas regions of an evaporating spray flow using filtered Rayleigh scattering.

    PubMed

    Allison, Patton M; McManus, Thomas A; Sutton, Jeffrey A

    2016-03-15

    This Letter demonstrates the application of filtered Rayleigh scattering (FRS) for quantitative two-dimensional fuel vapor/air mixing measurements in an evaporating hydrocarbon fuel spray flow. Using the FRS approach, gas-phase measurements are made in the presence of liquid-phase droplets without interference. Effective suppression of the liquid-phase droplet scattering using FRS is enabled by the high spectral purity of the current Nd:YAG laser system. Simultaneous Mie-scattering imaging is used to visualize the droplet field and illustrate the droplet loading under which the FRS imaging is applied in the current spray flows. The initial quantification of the FRS imaging is based on calibration measurements from a flow cell of known fuel vapor/air mixtures, while future work targets the utilization of a Rayleigh-Brillouin spectral model for quantification of the FRS signals. PMID:26977637

  4. Study on the interaction between torasemide and 12-tungstophosphoric acid by resonance Rayleigh scattering and resonance nonlinear scattering spectra and its analytical applications

    NASA Astrophysics Data System (ADS)

    Li, Cuixia; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang

    2011-09-01

    In pH 0.6-1.1 HCl-NaAc buffer solution, torasemide (TOR) reacted with TP to form a 3:1 ion-association complexes. As a result, not only the absorption spectra were changed, but also the intensities of resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were enhanced greatly. The maximum RRS, SOS and FDS wavelengths were located at 370, 333, 776 nm, respectively. Under given conditions, the intensities of RRS, SOS and FDS were all directly proportional to the concentration of TOR. The detection limits of RRS, SOS and FDS were 0.7173 ng mL -1, 7.007 ng mL -1 and 10.90 ng mL -1. The optimum conditions and the effects of coexisting substances on the reaction were investigated. The results showed that the method had good selectivity. Therefore, a highly sensitive, simple and quick method has been developed for the determination of TOR. The method can be applied satisfactorily to the determination of TOR in tablets and urine samples.

  5. LIGHT SCATTERING: Fast path-integration technique in simulation of light propagation through highly scattering objects

    NASA Astrophysics Data System (ADS)

    Voronov, Aleksandr V.; Tret'yakov, Evgeniy V.; Shuvalov, Vladimir V.

    2004-06-01

    Based on the path-integration technique and the Metropolis method, the original calculation scheme is developed for solving the problem of light propagation through highly scattering objects. The elimination of calculations of 'unnecessary' realisations and the phenomenological description of processes of multiple small-angle scattering provided a drastic increase (by nine and more orders of magnitude) in the calculation rate, retaining the specific features of the problem (consideration of spatial inhomogeneities, boundary conditions, etc.). The scheme allows one to verify other fast calculation algorithms and to obtain information required to reconstruct the internal structure of highly scattering objects (of size ~1000 scattered lengths and more) by the method of diffusion optical tomography.

  6. Numerical investigation of the Rayleigh hypothesis for electromagnetic scattering by a particle

    NASA Astrophysics Data System (ADS)

    Auguié, Baptiste; Somerville, Walter R. C.; Roache, Stanley; Le Ru, Eric C.

    2016-07-01

    The validity of the Rayleigh hypothesis (RH) has been a long-standing issue in the applicability of the T-matrix method to near-field calculations, and despite numerous theoretical works, the practical consequences for numerical simulations have remained unclear. Such calculations are increasingly important in the field of nano-optics, for which accurate and efficient modeling tools are in high demand. We here tackle this challenge by investigating numerically the convergence behavior of series expansions of the electric field around spheroidal particles, which provides us with unambiguous examples to clarify the conditions of convergence. This study is made possible by the combination of alternative methods to compute near-fields accurately, and crucially, the recent improvements in the calculation of T-matrix elements free from numerical instabilities, as such errors would otherwise obfuscate the intrinsic convergence properties of the field series. The resulting numerical confirmation for the range of validity of the RH, complemented by a better understanding of the convergence behavior of the field expansions, is a crucial step toward future developments.

  7. Dense medium radiative transfer theory for two scattering layers with a Rayleigh distribution of particle sizes

    SciTech Connect

    West, R.; Tsang, Leung; Winebrenner, D.P. )

    1993-03-01

    Dense medium radiative transfer theory is applied to a three-layer model consisting of two scattering layers overlying a homogeneous half space with a size distribution of particles in each layer. A model with a distribution of sizes gives quite different results than those obtained from a model with a single size. The size distribution is especially important in the low frequency limit when scattering is strongly dependent on particle size. The size distribution and absorption characteristics also affect the extinction behavior as a function of fractional volume. Theoretical results are also compared with experimental data. The sizes, permittivities, and densities used in the numerical illustrations are typical values for snow.

  8. LINE-INTERLOCKING EFFECTS ON POLARIZATION IN SPECTRAL LINES BY RAYLEIGH AND RAMAN SCATTERING

    SciTech Connect

    Sampoorna, M.; Nagendra, K. N.; Stenflo, J. O. E-mail: knn@iiap.res.in

    2013-06-20

    The polarized spectrum of the Sun and stars is formed from the scattering of anisotropic radiation on atoms. Interpretation of this spectrum requires the solution of polarized line transfer in multilevel atomic systems. While sophisticated quantum theories of polarized line formation in multilevel atomic systems exist, they are limited by the approximation of complete frequency redistribution in scattering. The partial frequency redistribution (PRD) in line scattering is a necessary component in modeling the polarized spectra of strong lines. The polarized PRD line scattering theories developed so far confine themselves to a two-level or a two-term atom model. In this paper, we present a heuristic approach to the problem of polarized line formation in multilevel atoms taking into account the effects of PRD and a weak magnetic field. Starting from the unpolarized PRD multilevel atom approach of Hubeny et al., we incorporate the polarization state of the radiation field. However, the lower level polarization is neglected. Two iterative methods of solving the polarized PRD line transfer in multilevel atoms are also presented. Taking the example of a five-level Ca II atom model, we present illustrative results for an isothermal one-dimensional model atmosphere.

  9. Modeling of light scattering by icy bodies

    NASA Astrophysics Data System (ADS)

    Kolokolova, L.; Mackowski, D.; Pitman, K.; Verbiscer, A.; Buratti, B.; Momary, T.

    2014-07-01

    As a result of ground-based, space-based, and in-situ spacecraft mission observations, a great amount of photometric, polarimetric, and spectroscopic data of icy bodies (satellites of giant planets, Kuiper Belt objects, comet nuclei, and icy particles in cometary comae and rings) has been accumulated. These data have revealed fascinating light-scattering phenomena, such as the opposition surge resulting from coherent backscattering and shadow hiding and the negative polarization associated with them. Near-infrared (NIR) spectra of these bodies are especially informative as the depth, width, and shape of the absorption bands of ice are sensitive not only to the ice abundance but also to the size of icy grains. Numerous NIR spectra obtained by Cassini's Visual and Infrared Mapping Spectrometer (VIMS) have been used to map the microcharacteristics of the icy satellites [1] and rings of Saturn [2]. VIMS data have also permitted a study of the opposition surge for icy satellites of Saturn [3], showing that coherent backscattering affects not only brightness and polarization of icy bodies but also their spectra [4]. To study all of the light-scattering phenomena that affect the photopolarimetric and spectroscopic characteristics of icy bodies, including coherent backscattering, requires computer modeling that rigorously considers light scattering by a large number of densely packed small particles that form either layers (in the case of regolith) or big clusters (ring and comet particles) . Such opportunity has appeared recently with a development of a new version MSTM4 of the Multi-Sphere T-Matrix code [5]. Simulations of reflectance and absorbance spectra of a ''target'' (particle layer or cluster) require that the dimensions of the target be significantly larger than the wavelength, sphere radius, and layer thickness. For wavelength-sized spheres and packing fractions typical of regolith, targets can contain dozens of thousands of spheres that, with the original MSTM

  10. A Study of Brownian Motion Using Light Scattering

    ERIC Educational Resources Information Center

    Clark, Noel A.; Lunacek, Joseph H.

    1969-01-01

    Describes an apparatus designed to investigate molecular motion by means of light scattering. Light from a He-Ne laser is focused into a cell containing a suspension of polystyrene spheres. The scattered light, collected on the photosurface of a photomultiplier tube, is analyzed. The apparatus won first prize in Demonstration Lecture Apparatus in…

  11. Fourier-transform light scattering of individual colloidal clusters.

    PubMed

    Yu, HyeonSeung; Park, HyunJoo; Kim, Youngchan; Kim, Mahn Won; Park, YongKeun

    2012-07-01

    We present measurements of the scalar-field light scattering of individual dimer, trimer, and tetrahedron shapes among colloidal clusters. By measuring the electric field with quantitative phase imaging at the sample plane and then numerically propagating to the far-field scattering plane, the two-dimensional light-scattering patterns from individual colloidal clusters are effectively and precisely retrieved. The measured scattering patterns are consistent with simulated patterns calculated from the generalized multiparticle Mie solution. PMID:22743460

  12. A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses

    NASA Astrophysics Data System (ADS)

    Walker, Bennett N.; James, Robert H.; Calogero, Don; Ilev, Ilko K.

    2015-09-01

    Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearly 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter.

  13. A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses

    SciTech Connect

    Walker, Bennett N.; James, Robert H.; Ilev, Ilko K.; Calogero, Don

    2015-09-15

    Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearly 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter.

  14. Aggregation behavior of illite using light scattering

    SciTech Connect

    Derrendinger, L.; Sposito, G.

    1995-12-01

    Stable environmental particles can be at the origin of facilitated transport of metals and organic compounds, especially contaminants. We investigated the destabilization (aggregation) kinetics of both a reference and a soil clay mineral: Imt-1 (Silver Hill) illite and Hanford soil illite, respectively. Dynamic and static light scattering was used to follow the aggregation kinetics and infer the structure of the resulting clusters. Kinetics curves showed exponential and power-law shapes, corresponding respectively to reaction-limited and diffusion-limited regimes. The fractal dimension of the clusters showed no observable change with the change of aggregation regime, its value always being between 2.10 and 2.25 ({plus_minus}0.12). The change in aggregation regime for Na-illite (or ccc) was measured to be 45 mol.m{sup -3}.

  15. Improved optics for laser light scattering

    NASA Technical Reports Server (NTRS)

    Cheung, H. Michael

    1989-01-01

    Laser light scattering experiments contemplated for use in a microgravity environment must conform to a number of operational constraints which do not apply on Earth. In particular, the use of index matching fluid to control flare is unacceptable. Work to eliminate index matching fluids by the use of high spatial resolution receiving optics is described. By increasing on-axis spatial resolution flare from the sample cell walls (both the cell sample and cell air interfaces) can be effectively prevented from reaching the photodetector. In general, improving the on-axis discrimination degrades the angular resolution of a receiving optical train. Several different possible configurations of receiving optics are compared for their spatial resolution and angular resolution. For cylinder symmetric optics, the dual lens, fourier transform pair, receiving train with a center mask located between the lenses gives the best on-axis spatial resolution.

  16. Modeling radiometric and polarized light scattering from exoplanet oceans and atmospheres

    NASA Astrophysics Data System (ADS)

    Zugger, Michael E.

    Proposed space-based observatories such as NASA's Terrestrial Planet Finder-Coronograph (TPF-C) may make it possible in the near future to detect the presence of oceans on nearby extrasolar planets (exoplanets) by studying the polarization of visible, infrared, or ultraviolet radiation reflected from the planet. In this dissertation, we model and analyze light scattering properties of various notional exoplanets, including brightness and polarization state versus wavelength and position in the orbit (orbital longitude, OL) in order to predict the potential observability of distant oceans. We find that total flux light curves from Lambertian and Rayleigh scattering dominated planets peak at full phase, OL = 180°, whereas ocean planets with thin atmospheres exhibit peak flux in the crescent phase near OL = 30°. The polarized results for ocean planets show that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column, dilute the polarization fraction and shift it away from the OL = 74° predicted by Fresnel theory. On planets for which Rayleigh scattering dominates, the polarization peaks near an orbital longitude of 90°, but clouds and Lambertian surfaces dilute and shift this peak to smaller OL, and a shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. In addition to end-member planets dominated by Lambertian or Rayleigh scattering, we simulate variations of "water Earths"; these are planets similar to Earth but completely covered by oceans, disturbed only by light winds. For these models, we also include US 1962 Standard Atmosphere absorption, and maritime aerosols using the standard 5 km low visibility and 23 km high visibility aerosols, and some other much higher visibilities for comparison. The polarization fraction for cases with Earth-like aerosols peaks at only about 0.15 at OL = 100° for the 5 km case, and at less than 0.35 at

  17. Collective processes during stimulated light scattering

    NASA Astrophysics Data System (ADS)

    Sidorovich, V. G.

    2013-06-01

    An approach to the analysis of the phase conjugation by stimulated light scattering that is alternative to the mode theory of 3D hologram, which is usually applied for these purposes, has been studied. As is known, the use of the mode theory is based on the phenomenological gain factor of the Stokes wave, which is induced by a pump wave in a nonlinear medium. The approach developed in this work directly considers the interaction between plane components of the pump and Stokes waves via hypersonic gratings of the dielectric permittivity, which the pump and Stokes waves induce in the medium. It has been shown that, as a result of the phase conjugation, two hypersonic gratings participate equally efficiently in the interaction between any pair of plane components of the pump and Stokes waves, with one of these gratings being excited by the interacting waves themselves. The other grating in each such pair is unambiguously identified with a simplest vector diagram. Conditions have been analyzed under which numerous other gratings, which could also participate in the interaction of each pair of plane components of the pump and Stokes waves without violating the Bragg conditions and the joining conditions of the transverse components of the wave vectors at the interface between the two media, contribute negligibly to stimulated light scattering. It has been shown that, if the pump is spatially coherent, the considered approach yields the same results as the standard mode theory does. In October 2011, I reported the results of this work at the Vavilov State Optical Institute at the Memorial Meeting "Half a Century of New Optics in Russia: Lasers, Nonlinear Optics, and Optical Holography" and at the International Conference "Laser Optics—2012" (June 2012).

  18. Study on the interaction between albendazole and eosin Y by fluorescence, resonance Rayleigh scattering and frequency doubling scattering spectra and their analytical applications

    NASA Astrophysics Data System (ADS)

    Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin

    In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356 nm. The detection limit for ABZ were 21.51 ng mL-1 for the fluorophotometry, 6.93 ng mL-1 for the RRS method and 12.89 ng mL-1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.

  19. Study on the interaction between albendazole and eosin Y by fluorescence, resonance Rayleigh scattering and frequency doubling scattering spectra and their analytical applications.

    PubMed

    Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin

    2014-05-21

    In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356nm. The detection limit for ABZ were 21.51ng mL(-)(1) for the fluorophotometry, 6.93ng mL(-)(1) for the RRS method and 12.89ng mL(-)(1) for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed. PMID:24594885

  20. LIGHT SCATTERING: Observation of multiple scattering of laser radiation from a light-induced jet of microparticles in suspension

    NASA Astrophysics Data System (ADS)

    Kondrat'ev, Andrei V.

    2004-06-01

    Variation in the correlation function of light multiply scattered by a random medium was observed with increasing the incident beam power. The light-induced motion of microparticles in suspension, caused by a high-power laser radiation, serves as an additional factor in the decorrelation of the scattered light. The experimental data are in good agreement with the results of theoretical analysis.

  1. Modeling fluorescent light distributions in scattering media

    NASA Astrophysics Data System (ADS)

    Phillips, Kevin G.; Jacques, Steven L.

    2010-02-01

    It is hoped that the non-invasive optical characterization of physiological features of normal and diseased epithelia can be assessed through the fluorescent emission of such tissues. With a high percentage of cancers arising in the epithelium, the characterization of carcinogenesis in such tissues is imperative. Fluorescent emission from the epithelium, e.g. oral mucosa, has been shown to be sensitive to physiological features, such as cellular morphology, and the amount and types of biochemical agents present in the tissue. Efforts to distinguish the spectral signatures of diseased and healthy states of tissues from fluorescence have been confounded by the distortion of the intrinsic fluorescent signature as a result of wavelength dependent absorption and scattering within the tissue. Theoretical models of light propagation in biological media are required for understanding the distortion of the intrinsic fluorescence arising from compromised tissues. In this work we model the distortion of the intrinsic fluorescence emitted from a tissue with wavelength dependent optical properties, arising from varying blood and water content, using the radiative transport equation. As an example, we demonstrate the ability of blood and water content to distort the signal of a white light source as it is embedded deeper into a tissue.

  2. Resonant Rayleigh scattering for the determination of trace amounts of mercury (II) with thiocyanate and basic triphenylmethane dyes

    SciTech Connect

    Liu, S.; Liu, Z.; Zhou, G.

    1998-05-01

    Intense resonance Rayleigh scattering (RRS) appears when mercury (II) reacts with thiocyanate and a basic triphenylmethane dye (BTPMD), such as crystal violet (CV), ethyl violet (EV), brilliant green (BG), malachite green (MG) or indine green (IG), to form an ion-association complex of the type (BTPMD){sub 2}[Hg(SCN){sub 4}]. The characteristics of RRS spectra of the ion-association complexes and suitable conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of mercury (II) in the range of 0--2.0 {micro}g/25 ml. The RRS methods have very high sensitivities for determination of mercury (II); their detection limits are between 1.68 ng/ml and 6.00 ng/ml on different dye systems. The effects of foreign ions and ways to improve the selectivity were studied. The new highly sensitive methods for the determination of trace amounts of mercury based on the RRS of the ion-association complexes have been developed.

  3. Angle-resolved light scattering of individual rod-shaped bacteria based on Fourier transform light scattering

    NASA Astrophysics Data System (ADS)

    Jo, Youngju; Jung, Jaehwang; Lee, Jee Woong; Shin, Della; Park, Hyunjoo; Nam, Ki Tae; Park, Ji-Ho; Park, Yongkeun

    2014-05-01

    Two-dimensional angle-resolved light scattering maps of individual rod-shaped bacteria are measured at the single-cell level. Using quantitative phase imaging and Fourier transform light scattering techniques, the light scattering patterns of individual bacteria in four rod-shaped species (Bacillus subtilis, Lactobacillus casei, Synechococcus elongatus, and Escherichia coli) are measured with unprecedented sensitivity in a broad angular range from -70° to 70°. The measured light scattering patterns are analyzed along the two principal axes of rod-shaped bacteria in order to systematically investigate the species-specific characteristics of anisotropic light scattering. In addition, the cellular dry mass of individual bacteria is calculated and used to demonstrate that the cell-to-cell variations in light scattering within bacterial species is related to the cellular dry mass and growth.

  4. Angle-resolved light scattering of individual rod-shaped bacteria based on Fourier transform light scattering

    PubMed Central

    Jo, YoungJu; Jung, JaeHwang; Lee, Jee Woong; Shin, Della; Park, HyunJoo; Nam, Ki Tae; Park, Ji-Ho; Park, YongKeun

    2014-01-01

    Two-dimensional angle-resolved light scattering maps of individual rod-shaped bacteria are measured at the single-cell level. Using quantitative phase imaging and Fourier transform light scattering techniques, the light scattering patterns of individual bacteria in four rod-shaped species (Bacillus subtilis, Lactobacillus casei, Synechococcus elongatus, and Escherichia coli) are measured with unprecedented sensitivity in a broad angular range from −70° to 70°. The measured light scattering patterns are analyzed along the two principal axes of rod-shaped bacteria in order to systematically investigate the species-specific characteristics of anisotropic light scattering. In addition, the cellular dry mass of individual bacteria is calculated and used to demonstrate that the cell-to-cell variations in light scattering within bacterial species is related to the cellular dry mass and growth. PMID:24867385

  5. Rayleigh rejection filters for 193-nm ArF laser Raman spectroscopy

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.

    1993-01-01

    Selected organic absorbers and their solvents are evaluated as spectral filters for the rejection of 193-nm Rayleigh light associated with the use of an ArF excimer laser for Raman spectroscopy. A simply constructed filter cell filled with 0.5 percent acetone in water and an optical path of 7 mm is shown effectively to eliminate stray Rayleigh light underlying the Raman spectrum from air while transmitting 60 percent of the Raman light scattered by O2.

  6. Vesicle sizing by static light scattering: a Fourier cosine transform approach

    NASA Astrophysics Data System (ADS)

    Wang, Jianhong; Hallett, F. Ross

    1995-08-01

    A Fourier cosine transform method, based on the Rayleigh-Gans-Debye thin-shell approximation, was developed to retrieve vesicle size distribution directly from the angular dependence of scattered light intensity. Its feasibility for real vesicles was partially tested on scattering data generated by the exact Mie solutions for isotropic vesicles. The noise tolerance of the method in recovering unimodal and biomodal distributions was studied with the simulated data. Applicability of this approach to vesicles with weak anisotropy was examined using Mie theory for anisotropic hollow spheres. A primitive theory about the first four moments of the radius distribution about the origin, excluding the mean radius, was obtained as an alternative to the direct retrieval of size distributions.

  7. Cloaking of solar cell contacts at the onset of Rayleigh scattering

    PubMed Central

    San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M.; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S. R. J.; Ripalda, José M.

    2016-01-01

    Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow. PMID:27339390

  8. Cloaking of solar cell contacts at the onset of Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M.; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S. R. J.; Ripalda, José M.

    2016-06-01

    Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow.

  9. Cloaking of solar cell contacts at the onset of Rayleigh scattering.

    PubMed

    San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S R J; Ripalda, José M

    2016-01-01

    Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow. PMID:27339390

  10. Recovering the vorticity of a light beam after scattering

    SciTech Connect

    Salla, Gangi Reddy Perumangattu, Chithrabhanu; Anwar, Ali; Prabhakar, Shashi; Singh, Ravindra P.

    2015-07-13

    We generate optical vortices and scatter them through a rough surface. However, the scattered light passing through a lens shows the same vorticity when probed at the Fourier plane. The vorticity is measured using a nonseparable state of polarization and orbital angular momentum of light as it cannot be confirmed by the standard interferometric technique. The observed vorticity is found to be independent of the amount of scattered light collected. Therefore, vortices can be used as information carriers even in the presence of scattering media. The experimental results are well supported by the theoretical results.

  11. Recovering the vorticity of a light beam after scattering

    NASA Astrophysics Data System (ADS)

    Salla, Gangi Reddy; Perumangattu, Chithrabhanu; Prabhakar, Shashi; Anwar, Ali; Singh, Ravindra P.

    2015-07-01

    We generate optical vortices and scatter them through a rough surface. However, the scattered light passing through a lens shows the same vorticity when probed at the Fourier plane. The vorticity is measured using a nonseparable state of polarization and orbital angular momentum of light as it cannot be confirmed by the standard interferometric technique. The observed vorticity is found to be independent of the amount of scattered light collected. Therefore, vortices can be used as information carriers even in the presence of scattering media. The experimental results are well supported by the theoretical results.

  12. Quasi-elastic light scattering from structured particles.

    PubMed

    Chen, S H; Holz, M; Tartaglia, P

    1977-01-01

    We present a formulation by which the scattered field correlation function of a nonstationary structured particle can be calculated. Specifically, we consider the case of micron-size bacteria, where the Rayleigh- Gans-Debye approximation may be used to evaluate the correlation function. We show that the width of the intensity correlation spectrum (as measured, for example, by the photon correlation technique) exhibits I an oscillatory behavior which is characteristic of the interference pattern produced by the internal structure. Two cases are of interest: diffusion and motility are considered in detail, and some evidence of the predicted behavior is shown from the photon correlation measurement of E. coli bacteria. PMID:20168450

  13. Particle detection by a light-scattering technique

    NASA Technical Reports Server (NTRS)

    Kormanyos, S.; Mastroeni, J.

    1972-01-01

    Instrument measures concentration of small particles in aqueous medium in terms of amount of light scattered and degree to which light transmission is attenuated. Sensitivity to small particles is optimized because both scattered and transmitted illumination levels are detected by photodiodes.

  14. UTILITY OF LIGHT SCATTER IN THE MORPHOLOGICAL ANALYSIS OF SPERM

    EPA Science Inventory

    By using an Ortho flow cytometer to detect the forward light scatter from a red (helium-neon) laser, we were able to differentiate the morphologically diverse sperm nuclei of four animal species. ytograms composed of the axial light loss and forward red scatter signals revealed u...

  15. NASA Laser Light Scattering Advanced Technology Development Workshop, 1988

    NASA Technical Reports Server (NTRS)

    Meyer, William V. (Editor)

    1989-01-01

    The major objective of the workshop was to explore the capabilities of existing and prospective laser light scattering hardware and to assess user requirements and needs for a laser light scattering instrument in a reduced gravity environment. The workshop addressed experimental needs and stressed hardware development.

  16. Utility of light scatter in the morphological analysis of sperm

    EPA Science Inventory

    We were able to differentiate the morphologically diverse sperm nuclei of four animal species by using an Ortho flow cytometer to detect the forward light scatter from a red (helium-neon) laser. Cytograms depicting the axial light loss and forward red scatter signals revealed uni...

  17. Theory of ghost scattering with incoherent light sources

    NASA Astrophysics Data System (ADS)

    Cheng, Jing

    2016-04-01

    Inspired by the idea of ghost imaging, we propose a ghost scattering scheme to study light scattering with incoherent light sources through the nonlocal correlation measurement of the differential scattering cross-section fluctuations in two different optical paths. We present a rigorous formal theory to describe the ghost scattering process. Also we have derived a simple and closed-form ghost scattering formula within the first-order Born approximation which is particularly suited for weak scatterers. We find that the scattering information of a test scatterer can be obtained by using only a single-pixel detector in the corresponding optical path through the nonlocal correlation measurement with the help of another reference path.

  18. Dynamic light scattering can determine platelet function

    NASA Astrophysics Data System (ADS)

    Lee, Nathan

    2011-10-01

    Platelet transfusions are life-saving procedures for patients who are bleeding or undergoing chemotherapy. The effectiveness of transfusions depends on the number of platelets transfused and the platelet function. Platelet function correlates with proportion of discoid to activated platelets, morphology response to temperature stress, and inversely correlates with microparticle content. ThromboLUX is a novel device that determines platelet function by measuring all of these characteristics using dynamic light scattering (DLS). During periods of stress, such as decreased temperature, cytoskeletal rearrangements will cause normal, discoid platelets to activate and become spiny spheres. The formation of pseudopods of various lengths facilitates the clotting cascade and also increases the apparent size of platelets. ThromboLUX uses a 37-20-37 C temperature cycle that mimics the bleeding, storage, and transfusion process. As the temperature fluctuates, DLS will measure the changing platelet hydrodynamic radius and the size of any microparticles present. ThromboLUX analysis of platelet concentrates in vitro would allow determination of high platelet function units before transfusion and would therefore improve transfusion outcomes and patient safety. This study examined how DLS is able to distinguish between discoid and activated platelets as well as measure the parameters that contribute to high platelet function.

  19. Light scattering by marine heterotrophic bacteria

    NASA Technical Reports Server (NTRS)

    Ulloa, Osvaldo; Sathyendranath, Shubha; Platt, Trevor; Quinones, Renato A.

    1992-01-01

    Mie theory is applied to estimate scattering by polydispersions of marine heterotrophic bacteria, and a simple expression is derived for the bacterial scattering coefficient. The error incurred in deriving bacterial optical properties by use of the van de Hulst approximations is computed. The scattering properties of natural bacterial assemblages in three marine environments, Georges Bank, Northeast Channel, and Sargasso Sea, are assessed by applying Mie theory to field data on bacterial size and abundance. Results are used to examine the potential contribution of bacteria to the scattering properties of seawater. The utility of using pigment data to predict the magnitude of scattering by bacteria is discussed.

  20. Anisotropic light scattering of individual sickle red blood cells

    NASA Astrophysics Data System (ADS)

    Kim, Youngchan; Higgins, John M.; Dasari, Ramachandra R.; Suresh, Subra; Park, YongKeun

    2012-04-01

    We present the anisotropic light scattering of individual red blood cells (RBCs) from a patient with sickle cell disease (SCD). To measure light scattering spectra along two independent axes of elongated-shaped sickle RBCs with arbitrary orientation, we introduce the anisotropic Fourier transform light scattering (aFTLS) technique and measured both the static and dynamic anisotropic light scattering. We observed strong anisotropy in light scattering patterns of elongated-shaped sickle RBCs along its major axes using static aFTLS. Dynamic aFTLS analysis reveals the significantly altered biophysical properties in individual sickle RBCs. These results provide evidence that effective viscosity and elasticity of sickle RBCs are significantly different from those of the healthy RBCs.

  1. Study of erythrocyte membrane fluctuation using light scattering analysis

    NASA Astrophysics Data System (ADS)

    Lee, Hoyoon; Lee, Sangyun; Park, YongKeun; Shin, Sehyun

    2016-03-01

    It is commonly known that alteration of erythrocyte deformability lead to serious microcirculatory diseases such as retinopathy, nephropathy, etc. Various methods and technologies have been developed to diagnose such membrane properties of erythrocytes. In this study, we developed an innovative method to measure hemorheological characteristics of the erythrocyte membrane using a light scattering analysis with simplified optic setting and multi-cell analysis as well. Light scattering intensity through multiple erythrocytes and its power density spectrum were obtained. The results of light scattering analyses were compared in healthy control and artificially hardened sample which was treated with glutaraldehyde. These results were further compared with conventional assays to measure deformable property in hemorheology. We found that light scattering information would reflect the disturbance of membrane fluctuation in artificially damaged erythrocytes. Therefore, measuring fluctuation of erythrocyte membrane using light scattering signal could facilitate simple and precise diagnose of pathological state on erythrocyte as well as related complications.

  2. Limitations for heterodyne detection of Brillouin scattered light

    SciTech Connect

    Allemeier, R.T.; Wagner, J.W.; Telschow, K.L.

    1995-01-01

    One means by which elastic properties of a material may be determined is measuring sound wave velocities in the material, from which elastic moduli of interest can be computed. Velocity can be measured by conventional piezoelectric transduction techniques, by applying laser ultrasonics, or by using Brillouin-scattering methods. Brillouin-scattering techniques for determining the sound wave velocity are particularly attractive since they are completely noninvasive. Only a probe beam of light is required since the thermal energy in the material provides the elastic motion. Heterodyne methods for detection of Brillouin-scattered light are considered one possible means to increase the speed of the scattered light frequency detection. Results of experiments with simulated Brillouin scattering suggest that heterodyne detection of the Brillouin-scattered light is feasible. Experiments to detect Brillouin-scattered light, with water as the scattering medium, were designed and interpreted using the results of the simulated scattering experiments. Overall, results showed that it is difficult to narrow the linewidth for Brillouin scattering to an acceptable level. The results given indicate that heterodyne detection of the Brillouin components requires detection bandwidths that are quite small, perhaps 10 Hz or lower. These small bandwidths can be routinely achieved using lock-in amplifier techniques.

  3. EUV and visible light imaging of magnetic reconnection associated with Rayleigh-Taylor instability in MHD driven jets

    NASA Astrophysics Data System (ADS)

    Chai, Kil-Byoung; Bellan, Paul

    2014-10-01

    A high-speed EUV movie camera has been developed for imaging magnetic reconnection in the Caltech MHD-driven jet experiment. In order to achieve high temporal resolution, a high-speed visible camera (up to 2 × 108 fps) is utilized with a fast-decaying YAG:Ce scintillator crystal that converts EUV radiation into visible light. A custom-designed, broadband Si/Mo multilayer mirror having central wavelength at 36 nm is used to form an image on the scintillator crystal. The jet 3D structure is imaged in visible light by a two-branch fiber bundle which simultaneously captures end and side view images. The fiber bundle is coupled to the high-speed visible light movie camera. Comparison of EUV and visible light movies shows that the EUV images are similar to visible light images at early times. However, the EUV images differ from the visible light images when a Rayleigh-Taylor instability occurs. A small segment near the apex of the kinked jet becomes extremely bright in EUV but dark in visible light. Future plans include further investigation of this bright spot, plasma evolution and upgrade of optical sensitivity by better optical coupling to the scintillator crystal.

  4. A method based on light scattering to estimate the concentration of virus particles without the need for virus particle standards☆

    PubMed Central

    Makra, István; Terejánszky, Péter; Gyurcsányi, Róbert E.

    2015-01-01

    Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards. We have adapted a static light scattering based method for the quantification of virus particles (shown for poliovirus) without the need of virus particle standards. Instead, as standards, well-characterized polymeric nanoparticle solutions are used. The method is applicable for virus particles acting as Rayleigh scatterers, i.e., virus particles with equivalent diameters up to ca. 1/10th of the wavelength of the scattered monochromatic light (∼70 nm diameter). Further limitations may arise if the refractive index of the virus is unavailable or cannot be calculated based on its composition, such as in case of enveloped viruses. The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied. The method consists of: • Measuring the intensity of the light scattered by viruses suspended in an aqueous solution. • Measuring the intensity of the light scattered by polymeric nanoparticles of known concentration and comparable size with the investigated virus particle. • The concentration of virus nanoparticles can be calculated based on the two measured scattered light intensities by knowing the refractive index of the dispersing solution, of the polymer and virus nanoparticles as well as their relative sphere equivalent diameters. PMID:26150976

  5. A method based on light scattering to estimate the concentration of virus particles without the need for virus particle standards.

    PubMed

    Makra, István; Terejánszky, Péter; Gyurcsányi, Róbert E

    2015-01-01

    Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards. We have adapted a static light scattering based method for the quantification of virus particles (shown for poliovirus) without the need of virus particle standards. Instead, as standards, well-characterized polymeric nanoparticle solutions are used. The method is applicable for virus particles acting as Rayleigh scatterers, i.e., virus particles with equivalent diameters up to ca. 1/10th of the wavelength of the scattered monochromatic light (∼70 nm diameter). Further limitations may arise if the refractive index of the virus is unavailable or cannot be calculated based on its composition, such as in case of enveloped viruses. The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied. The method consists of: •Measuring the intensity of the light scattered by viruses suspended in an aqueous solution.•Measuring the intensity of the light scattered by polymeric nanoparticles of known concentration and comparable size with the investigated virus particle.•The concentration of virus nanoparticles can be calculated based on the two measured scattered light intensities by knowing the refractive index of the dispersing solution, of the polymer and virus nanoparticles as well as their relative sphere equivalent diameters. PMID:26150976

  6. Narrowly peaked forward light scattering on particulate media: II. Angular spreading of light scattered by polystyrene microspheres

    NASA Astrophysics Data System (ADS)

    Turcu, Ioan; Bratfalean, Radu; Neamtu, Silvia

    2008-07-01

    The adequacy of the effective phase function (EPF) used to describe the light scattered at small angles was tested on aqueous suspensions of polystyrene microspheres. Angular resolved light scattering measurements were performed on two types of latex suspension, which contained polystyrene spheres of 3 µm and 5 µm diameters, respectively. The experimental data were fitted with two EPF approximants. If the polystyrene spheres are at least 3 µm in diameter the quasi-ballistic light scattering process can be described relatively well by the EPF in a small angular range centered in the forward direction. The forward light scattering by macroscopic samples containing microspheres can be modeled relatively well if the true Mie single particle scattering phase function is replaced by a simpler Henyey-Greenstein dependence having the same width at half-height as the first scattering lobe.

  7. Redistribution - Why half a collision is better than a whole one. [spectra of scattered light from perturbed atomic system

    NASA Technical Reports Server (NTRS)

    Cooper, J.

    1983-01-01

    The study of spectral line shapes has traditionally been mainly concerned with the measurement and interpretation of absorption or emission profiles. Often only the line widths are studied. The present investigation has the objective to evaluate the additional information which can be obtained by scattering light (usually from a laser) from an atomic system which is being perturbed by collisions. A scattering experiment is discussed. The scattered light consists of two components, a (coherent) Rayleigh component and a redistributed (fluorescent) component. In order to obtain the absorption spectrum, questions regarding the probability of photon absorption are considered. By observing the fluorescence subsequent to absorption during a collision it is found possible to obtain information on the evolution of the system from the point of absorption to the completion of the collision. The information on the intracollisional evolution is the justification for the title of the study, namely 'Why half a collision is better than a whole one'.

  8. DUST SCATTERING IN TURBULENT MEDIA: CORRELATION BETWEEN THE SCATTERED LIGHT AND DUST COLUMN DENSITY

    SciTech Connect

    Seon, Kwang-Il; Witt, Adolf N.

    2013-12-01

    Radiative transfer models in a spherical, turbulent interstellar medium (ISM), in which the photon source is situated at the center, are calculated to investigate the correlation between the scattered light and the dust column density. The medium is modeled using fractional Brownian motion structures that are appropriate for turbulent ISM. The correlation plot between the scattered light and optical depth shows substantial scatter and deviation from simple proportionality. It was also found that the overall density contrast is smoothed out in scattered light. In other words, there is an enhancement of the dust-scattered flux in low-density regions, while the scattered flux is suppressed in high-density regions. The correlation becomes less significant as the scattering becomes closer to being isotropic and the medium becomes more turbulent. Therefore, the scattered light observed in near-infrared wavelengths would show much weaker correlation than the observations in optical and ultraviolet wavelengths. We also find that the correlation plot between scattered lights at two different wavelengths shows a tighter correlation than that of the scattered light versus the optical depth.

  9. Projection screen having reduced ambient light scattering

    DOEpatents

    Sweatt, William C.

    2010-05-11

    An apparatus and method for improving the contrast between incident projected light and ambient light reflected from a projection screen are described. The efficiency of the projection screen for reflection of the projected light remains high, while permitting the projection screen to be utilized in a brightly lighted room. Light power requirements from the projection system utilized may be reduced.

  10. An analysis of scattered light in low dispersion IUE spectra

    NASA Technical Reports Server (NTRS)

    Basri, G.; Clarke, J. T.; Haisch, B. M.

    1985-01-01

    A detailed numerical simulation of light scattering from the low-resolution grating in the short wavelength spectrograph of the IUE Observatory was developed, in order to quantitatively analyze the effects of scattering on both continuum and line emission spectra. It is found that: (1) the redistribution of light by grating scattering did not appreciably alter either the shape or the absolute flux level of continuum spectra for A-F stars; (2) late-type stellar continua showed a tendency to flatten when observed in scattered light toward the shorter wavelengths; and (3) the effect of grating scattering on emission lines is to decrease measured line intensities by an increasing percentage toward the shorter wavelengths. The spectra obtained from scattering experiments for solar-type and late type stars are reproduced in graphic form.

  11. Dynamic Light Scattering of Diabetic Vitreopathy

    NASA Technical Reports Server (NTRS)

    Sebag, J.; Ansari, Rafat R.; Dunker, Stephan; Suh, Kwang I.

    1999-01-01

    Diabetes induces pathology throughout the body via nonenzymatic glycation of proteins. Vitreous, which is replete with type 11 collagen, undergoes significant changes in diabetes. The resultant diabetic vitreopathy plays an important role in diabetic retinopathy. Detecting these molecular changes could provide insight into diabetic eye disease as well as molecular effects elsewhere in the body. Human eyes were obtained at autopsy and studied in the fresh, unfixed state. Sclera, choroid, and retina were dissected off the vitreous for dark-field slit microscopy and dynamic light scattering (DLS). For the former, the entire vitreous was exposed. For the latter, only a window at the equator was dissected in some specimens, and the anterior segment was removed leaving the posterior lens capsule intact in others. DLS was performed to determine particle sizes at multiple sites 0.5 mm apart, spanning the globe at the equator (window dissections) and along the antero-posterior axis. Dark-field slit microscopy in diabetic subjects detected findings typical of age-related vitreous degeneration, but at much younger ages than nondiabetic controls. Noninvasive DLS measurements found a greater heterogeneity and larger particle sizes in vitreous of subjects with diabetes as compared to age-matched controls. DLS can detect and quantify the early molecular effects that cause vitreous collagen fibrils to cross-link and aggregate. This could provide valuable insight into ocular and systemic effects of hyperglycemia, because the molecular changes in diabetic vitreopathy could serve as an index of such effects throughout the body. In addition to the diagnostic implications, this methodology could provide a rapid, reproducible way to monitor the response to therapy with novel agents intended to prevent the complications of diabetes on a molecular level.

  12. Experimental studies of light propagation in active scattering media

    NASA Astrophysics Data System (ADS)

    Perkins, Amy Elizabeth

    1998-10-01

    Over the past several years there has been a great deal of renewed interest in multiple scattering systems with gain. Laser action has been demonstrated in systems containing high gain laser dyes mixed with passive scattering particles. In these materials, known as photonic paint, the scatterers redirect the light and provide the feedback mechanism to initiate lasing. A method of decreasing the linewidth which has been used in conventional laser systems is injection locking, in which a seed at the desired wavelength is introduced into the cavity to initiate lasing. Experiments are presented which demonstrate injection locking of this new laser system. It is also of particular interest to study the phenomenon of weak localization of light in these photonic paint systems. The interference between scattered light paths increases the probability of light traveling opposite to the direction of the incident light, and produces a cone of enhanced reflected light in that direction. In the presence of amplification, the coherent backscattering cone narrows. In this high gain scattering system, an unstudied regime can be achieved in which significant amplification takes place over one scattering length. The results of the coherent backscattering experiment in a high gain scattering system is discussed. There are certain intrinsic problems with inversion gain systems, such as photonic paint, which makes the narrowing of the coherent backscattering cone less pronounced. In Raman materials, these effects are greatly reduced. Experimental studies of the amplification of a probe beam in a disordered Raman scattering medium, and the Monte Carlo simulations of this experiment, are presented. It is also of interest to study absorptive scattering systems which appear in a number of different situations, including the determination of the excitation volume in a scattering gain system and the modeling of biological tissue. The addition of an absorbing species into a scattering medium

  13. Numerical studies of the scattering of light from a two-dimensional randomly rough interface between two dielectric media

    NASA Astrophysics Data System (ADS)

    Hetland, Ø. S.; Maradudin, A. A.; Nordam, T.; Simonsen, I.

    2016-05-01

    The scattering of polarized light incident from one dielectric medium on its two-dimensional randomly rough interface with a second dielectric medium is studied. A reduced Rayleigh equation for the scattering amplitudes is derived for the case where p- or s-polarized light is incident on this interface, with no assumptions being made regarding the dielectric functions of the media. Rigorous, purely numerical, nonperturbative solutions of this equation are obtained. They are used to calculate the reflectivity and reflectance of the interface, the mean differential reflection coefficient, and the full angular distribution of the intensity of the scattered light. These results are obtained for both the case where the medium of incidence is the optically less dense medium and in the case where it is the optically more dense medium. Optical analogs of the Yoneda peaks observed in the scattering of x rays from metal surfaces are present in the results obtained in the latter case. Brewster scattering angles for diffuse scattering are investigated, reminiscent of the Brewster angle for flat-interface reflection, but strongly dependent on the angle of incidence. When the contribution from the transmitted field is added to that from the scattered field it is found that the results of these calculations satisfy unitarity with an error smaller than 10-4.

  14. Light scattering by a finite obstacle and fano resonances.

    PubMed

    Tribelsky, Michael I; Flach, Sergej; Miroshnichenko, Andrey E; Gorbach, Andrey V; Kivshar, Yuri S

    2008-02-01

    The conditions for observing Fano resonances at elastic light scattering by a single finite-size obstacle are discussed. General arguments are illustrated by consideration of the scattering by a small (relative to the incident light wavelength) spherical obstacle based upon the exact Mie solution of the diffraction problem. The most attention is paid to recently discovered anomalous scattering. An exactly solvable one-dimentional discrete model with nonlocal coupling for simulating diffraction in wave scattering in systems with reduced spatial dimensionality is also introduced and analyzed. Deep connections between the resonances in the continuous and discrete systems are revealed. PMID:18352275

  15. Correlating the morphological and light scattering properties of biological cells

    NASA Astrophysics Data System (ADS)

    Moran, Marina

    The scattered light pattern from a biological cell is greatly influenced by the internal structure and optical properties of the cell. This research project examines the relationships between the morphological and scattering properties of biological cells through numerical simulations. The mains goals are: (1) to develop a procedure to analytically model biological cells, (2) to quantitatively study the effects of a range of cell characteristics on the features of the light scattering patterns, and (3) to classify cells based on the features of their light scattering patterns. A procedure to create an analytical cell model was developed which extracted structural information from the confocal microscopic images of cells and allowed for the alteration of the cell structure in a controlled and systematic way. The influence of cell surface roughness, nuclear size, and mitochondrial volume density, spatial distribution, size and shape on the light scattering patterns was studied through numerical simulations of light scattering using the Discrete Dipole Approximation. It was found that the light scattering intensity in the scattering angle range of 25° to 45° responded to changes in the surface fluctuation of the cell and the range of 90° to 110° was well suited for characterization of mitochondrial density and nuclear size. A comparison of light scattering pattern analysis methods revealed that the angular distribution of the scattered light and Gabor filters were most helpful in differentiating between the cell characteristics. In addition, a measured increase in the Gabor energy of the light scattering patterns in response to an increase in the complexity of the cell models suggested that a complex nuclear structure and mitochondria should be included when modeling biological cells for light scattering simulations. Analysis of the scattering pattern features with Gabor filters resulted in discrimination of the cell models according to cell surface roughness

  16. Infrared light scattering in biological tissues and fluids

    NASA Astrophysics Data System (ADS)

    Thomas, Gordon A.; Koo, Tae-Woong; Dasari, Ramachandra R.; Feld, Michael S.

    2001-03-01

    We have studied the elastic and Raman scattering from whole blood, blood serum and related biological fluids and tissues. The motivation of this work is to determine the composition and elastic scattering properties with a non-invasive, optical method. An example of the possible applications is the determination of the glucose concentration and its variations in a way that would be clinically effective for patients with diabetes. We have imaged the elastically scattered light and determined the scattering parameters in order to assess appropriate geometries for efficient collection of the Raman scattering. Using the Raman apectra we have determined the concentration of glucose and the other analytes under laboratory conditions.

  17. Measurements and interpretations of light scattering from intact biological cells

    NASA Astrophysics Data System (ADS)

    Wilson, Jeremy D.

    Visible light interacts with biological cells primarily through elastic scattering. The details of how cells scatter light depend on their morphology and their substructures. In this thesis we first present a series of experiments and models to discern the specific contributions of certain sub-cellular constituents to whole-cell scattering. Exploiting the findings of those studies, we report on experiments within model systems of cell death that demonstrate the potential of light scattering measurements as a tool in modern biology. Instrumentation capable of exploiting the findings of this thesis from a biology-relevant microscopy platform is designed and developed. A Mie theory based interpretation of light scattering signals originating from a collection of particles with a broad size distribution is developed. Upon applying this model to scattering data from intact cells, we find that it robustly extracts the size scale of dominant light scattering particles, suggests that scattering measurements are sensitive primarily to mitochondrial and lysosomal morphology, and unites conflicting results in the literature. Using this model as a basis, we present a collection of studies in which we use various strategies of photodynamic therapy (PDT) as a biophysical tool to perturb mitochondria and lysosomes, and observe the effects of these perturbations on whole-cell scattering. Through these experiments, we are able to discern the individual contributions of mitochondria and lysosomes to whole-cell light scattering, and demonstrate that mitochondria are responsible for roughly 80% of the scattering signal. Results of experiments aimed at demonstrating the potential role that light scattering measurements have to play in future studies of cell death biology are presented. We first show that mitochondrial-PDT-induced morphology changes measured with light scattering map into the cell killing efficacy of the therapy. We next demonstrate that mitochondrial

  18. Strutt, John William [Lord Rayleigh] (1842-1919)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Born in Langford Grove (near Maldon), Essex, England, Nobel prizewinner (1904) for the discovery of argon. He worked in many areas of physics, including electromagnetism and sound; the Rayleigh theory of the scattering of light was the first correct explanation of why the sky is blue....

  19. Thomson Scattering Lineshape Fitting for Plasma Diagnostics

    Energy Science and Technology Software Center (ESTSC)

    1994-02-04

    HFIT30 is used for interpreting lineshape (intensity versus frequency) data from Thomson and Rayleigh light scattering from a plasma, to obtain temperatures and number densities of the component species in the plasma.

  20. Laser Diode Raman Spectroscopy Without the Rayleigh Line.

    NASA Astrophysics Data System (ADS)

    Sabbaghzadeh, Jamshid

    1995-01-01

    The intensity of Rayleigh scattering which is typically four to ten orders of magnitude larger than rotational Raman scattering sets severe limitations on the measurements of Raman intensities close to the excitation line. In order to remove this unwanted light, it is common to use either a subtractive filter stage double spectrometer or a holographic filter. These solutions carry a high price since some parts of the pure rotational spectra of the molecule very close to the Rayleigh line will be blocked. In addition, the combination of a filter stage with the spectrograph makes the device more cumbersome and prevents Raman spectroscopy from being used in many applications, where high sensitivity such as industrial continuous emission monitoring (CEM) is required. We have succeeded to suppress the Rayleigh line with a resonant atomic vapor cell which can reduce the intensity of the Rayleigh line by many orders of magnitude. Rubidium atoms, which have a resonance line at 780.027 nm, absorb the Rayleigh light very effectively if the incident laser frequency is tuned to the absorption lines of the atoms. This technique makes it possible to measure the Raman intensities of gases only a few GHz away from the Rayleigh line without loss of intensities.

  1. Light scattering from a moving atom.

    PubMed

    Guo, Wei

    2012-12-01

    In this work, scattering of an incident electric field from a moving atom is reexamined classically in two steps: the time-dependent current density created by the field inside the atom is first calculated under the electric-dipole approximation, and is then used to calculate the field scattered from the atom. Unlike the conventional frame-hopping method, the present method does not need to treat the Doppler effect as an effect separated from the scattering process, and it derives instead of simply uses the Doppler effect. PMID:23455906

  2. How to distinguish elastically scattered light from Stokes shifted light for solid-state lighting?

    NASA Astrophysics Data System (ADS)

    Meretska, M. L.; Lagendijk, A.; Thyrrestrup, H.; Mosk, A. P.; IJzerman, W. L.; Vos, W. L.

    2016-03-01

    We have studied the transport of light through phosphor diffuser plates that are used in commercial solid-state lighting modules (Fortimo). These polymer plates contain YAG:Ce+3 phosphor particles that both elastically scatter and Stokes shift light in the visible wavelength range (400-700 nm). We excite the phosphor with a narrowband light source and measure spectra of the outgoing light. The Stokes shifted light is spectrally separated from the elastically scattered light in the measured spectra, and using this technique, we isolate the elastic transmission of the plates. This result allows us to extract the transport mean free path ltr over the full wavelength range by employing diffusion theory. Simultaneously, we determine the absorption mean free path labs in the wavelength range 400 to 530 nm where YAG:Ce+3 absorbs. The diffuse absorption (μa=1/labs ) spectrum is qualitatively similar to the absorption coefficient of YAG:Ce+3 in powder, with the diffuse spectrum being wider than the absorption coefficient. We propose a design rule for the solid-state lighting diffuser plates.

  3. Bright-White Beetle Scales Optimise Multiple Scattering of Light

    NASA Astrophysics Data System (ADS)

    Burresi, Matteo; Cortese, Lorenzo; Pattelli, Lorenzo; Kolle, Mathias; Vukusic, Peter; Wiersma, Diederik S.; Steiner, Ullrich; Vignolini, Silvia

    2014-08-01

    Whiteness arises from diffuse and broadband reflection of light typically achieved through optical scattering in randomly structured media. In contrast to structural colour due to coherent scattering, white appearance generally requires a relatively thick system comprising randomly positioned high refractive-index scattering centres. Here, we show that the exceptionally bright white appearance of Cyphochilus and Lepidiota stigma beetles arises from a remarkably optimised anisotropy of intra-scale chitin networks, which act as a dense scattering media. Using time-resolved measurements, we show that light propagating in the scales of the beetles undergoes pronounced multiple scattering that is associated with the lowest transport mean free path reported to date for low-refractive-index systems. Our light transport investigation unveil high level of optimisation that achieves high-brightness white in a thin low-mass-per-unit-area anisotropic disordered nanostructure.

  4. Bright-white beetle scales optimise multiple scattering of light.

    PubMed

    Burresi, Matteo; Cortese, Lorenzo; Pattelli, Lorenzo; Kolle, Mathias; Vukusic, Peter; Wiersma, Diederik S; Steiner, Ullrich; Vignolini, Silvia

    2014-01-01

    Whiteness arises from diffuse and broadband reflection of light typically achieved through optical scattering in randomly structured media. In contrast to structural colour due to coherent scattering, white appearance generally requires a relatively thick system comprising randomly positioned high refractive-index scattering centres. Here, we show that the exceptionally bright white appearance of Cyphochilus and Lepidiota stigma beetles arises from a remarkably optimised anisotropy of intra-scale chitin networks, which act as a dense scattering media. Using time-resolved measurements, we show that light propagating in the scales of the beetles undergoes pronounced multiple scattering that is associated with the lowest transport mean free path reported to date for low-refractive-index systems. Our light transport investigation unveil high level of optimisation that achieves high-brightness white in a thin low-mass-per-unit-area anisotropic disordered nanostructure. PMID:25123449

  5. Bright-White Beetle Scales Optimise Multiple Scattering of Light

    PubMed Central

    Burresi, Matteo; Cortese, Lorenzo; Pattelli, Lorenzo; Kolle, Mathias; Vukusic, Peter; Wiersma, Diederik S.; Steiner, Ullrich; Vignolini, Silvia

    2014-01-01

    Whiteness arises from diffuse and broadband reflection of light typically achieved through optical scattering in randomly structured media. In contrast to structural colour due to coherent scattering, white appearance generally requires a relatively thick system comprising randomly positioned high refractive-index scattering centres. Here, we show that the exceptionally bright white appearance of Cyphochilus and Lepidiota stigma beetles arises from a remarkably optimised anisotropy of intra-scale chitin networks, which act as a dense scattering media. Using time-resolved measurements, we show that light propagating in the scales of the beetles undergoes pronounced multiple scattering that is associated with the lowest transport mean free path reported to date for low-refractive-index systems. Our light transport investigation unveil high level of optimisation that achieves high-brightness white in a thin low-mass-per-unit-area anisotropic disordered nanostructure. PMID:25123449

  6. Dynamic light scattering by polyelectrolytes in low ionic strength buffers

    SciTech Connect

    Schmitz, K.S.

    1993-12-31

    Dynamic light scattering is a generic term which refers to all techniques that monitor fluctuation in the intensity of scattered light. Quasielastic light scattering (QELS) is that configuration in which no external field is applied in the course of data collection. In the case of charged macroions, QELS studies indicate a bifurcation in the relaxation modes as the ionic strength is lowered. This phenomenon is discussed in terms of an extended couple mode theory in which the dynamics of the macroions are coupled with those of the electrolyte ions. The QELS results are correlated with studies in which external electric fields of wave forms that are constant (ELS, electrophoretic light scattering) or pure sinusoidal (QELS-SEF).

  7. Probing confined interfacial excitations in buried layers by Brillouin light scattering

    NASA Astrophysics Data System (ADS)

    Zhang, Xinya; Sooryakumar, R.

    2002-03-01

    Brillouin light scattering from silicon oxynitride films grown on GaAs reveals a low frequency elastic wave excitation at frequencies lying below that of the Rayleigh surface wave. This mode, identified as an excitation localized by the interface, arises from the presence of a soft, thin transition layer between the film and substrate. The results are discussed in the framework of a Green's function formalism that reproduces the experimental features and illustrates the nature of the mode and its difference from Stoneley excitations that are predicted in special cases for an abrupt interface separating two semi-infinite solid media. Observations of this low frequency excitation offer a previously unexplored approach to characterize, non-destructively, the elastic properties of buried interfaces.

  8. Probing confined interfacial excitations in buried layers by Brillouin light scattering

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Sooryakumar, R.

    2002-06-01

    Brillouin light scattering from silicon oxynitride films grown on GaAs reveals an excitation at frequencies lying below that of the Rayleigh surface wave. The mode, identified as a localized interfacial excitation, arises from the presence of a soft, thin transition layer between the film and substrate. The results are discussed in the framework of a Green's function formalism that reproduces the experimental features and illustrates the nature of the mode and its difference from Stoneley excitations that exist in special cases for an abrupt interface separating two semi-infinite solid media. Observations of this low-frequency excitation offer a previously unexplored approach to characterize, nondestructively, the elastic properties of buried interfaces.

  9. Hierarchical mesoporous silica nanoparticles as superb light scattering materials.

    PubMed

    Ryu, Jaehoon; Yun, Juyoung; Lee, Jungsup; Lee, Kisu; Jang, Jyongsik

    2016-02-01

    A novel approach to enhance the light scattering effect was explored by applying hierarchical silica nanoparticles in DSSCs as scattering layers. The WSN-incorporated cells showed a PCE value of 9.53% and a PCE enhancement of 30.19% compared with those of the reference cells. PMID:26699659

  10. Design of fiber optic probes for laser light scattering

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans S.; Chu, Benjamin

    1989-01-01

    A quantitative analysis is presented of the role of optical fibers in laser light scattering. Design of a general fiber optic/microlens probe by means of ray tracing is described. Several different geometries employing an optical fiber of the type used in lightwave communications and a graded index microlens are considered. Experimental results using a nonimaging fiber optic detector probe show that due to geometrical limitations of single mode fibers, a probe using a multimode optical fiber has better performance, for both static and dynamic measurements of the scattered light intensity, compared with a probe using a single mode fiber. Fiber optic detector probes are shown to be more efficient at data collection when compared with conventional approaches to measurements of the scattered laser light. Integration of fiber optic detector probes into a fiber optic spectrometer offers considerable miniaturization of conventional light scattering spectrometers, which can be made arbitrarily small. In addition static and dynamic measurements of scattered light can be made within the scattering cell and consequently very close to the scattering center.

  11. Depolarization of Light Scattered from Rough Cylindrical Surfaces

    NASA Astrophysics Data System (ADS)

    Aparicio, R.; Quintián, F. Perez; Rebollo, M. A.

    2008-04-01

    In this work we study the state of polarization of light scattered from rough cylindrical surfaces. The experimental results show that the amount of cross-polarized light at a particular observation angle is correlated with the roughness of the cylinders. We compare these results with those obtained using the Kirchhoff's vector theory and analyze if the differences can be modeled on multiple-scattering effects.

  12. Evaluation of advanced light scattering technology for microgravity experiments

    NASA Technical Reports Server (NTRS)

    Fredericks, W. J.; Rosenblum, W. M.

    1990-01-01

    The capabilities of modern light scattering equipment and the uses it might have in studying processes in microgravity are evaluated. Emphasis is on the resolution of polydisperse systems. This choice was made since a major use of light scattering was expected to be the study of crystal growth of macromolecules in low gravity environments. An evaluation of a modern photon correlation spectrometer and a Mie spectrometer is presented.

  13. Efficient light propagation for multiple anisotropic volume scattering

    SciTech Connect

    Max, N. |

    1993-12-01

    Realistic rendering of participating media like clouds requires multiple anisotropic light scattering. This paper presents a propagation approximation for light scattered into M direction bins, which reduces the ``ray effect`` problem in the traditional ``discrete ordinates`` method. For a volume of n{sup 3} elements, it takes O(M n{sup 3} log n + M{sup 2} n{sup 3}) time and O(M n{sup 3}) space.

  14. Surface roughness considerations for atmospheric correction of ocean color sensors. I - The Rayleigh-scattering component. II - Error in the retrieved water-leaving radiance

    NASA Technical Reports Server (NTRS)

    Gordon, Howard R.; Wang, Menghua

    1992-01-01

    The first step in the Coastal Zone Color Scanner (CZCS) atmospheric-correction algorithm is the computation of the Rayleigh-scattering (RS) contribution, L sub r, to the radiance leaving the top of the atmosphere over the ocean. In the present algorithm, L sub r is computed by assuming that the ocean surface is flat. Calculations of the radiance leaving an RS atmosphere overlying a rough Fresnel-reflecting ocean are presented to evaluate the radiance error caused by the flat-ocean assumption. Simulations are carried out to evaluate the error incurred when the CZCS-type algorithm is applied to a realistic ocean in which the surface is roughened by the wind. In situations where there is no direct sun glitter, it is concluded that the error induced by ignoring the Rayleigh-aerosol interaction is usually larger than that caused by ignoring the surface roughness. This suggests that, in refining algorithms for future sensors, more effort should be focused on dealing with the Rayleigh-aerosol interaction than on the roughness of the sea surface.

  15. Interpretation of light scattering and turbidity measurements in aggregated systems: effect of intra-cluster multiple-light scattering.

    PubMed

    Soos, Miroslav; Lattuada, Marco; Sefcik, Jan

    2009-11-12

    In this work we studied the effect of intracluster multiple-light scattering on the scattering properties of a population of fractal aggregates. To do so, experimental data of diffusion-limited aggregation for three polystyrene latexes with similar surface properties but different primary particle diameters (equal to 118, 420, and 810 nm) were obtained by static light scattering and by means of a spectrophotometer. In parallel, a population balance equation (PBE) model, which takes into account the effect of intracluster multiple-light scattering by solving the T-matrix and the mean-field version of T-matrix, was formulated and validated against time evolution of the root mean radius of gyration, , of the zero angle intensity of scattered light, I(0), and of the turbidity, tau. It was found that the mean-field version of the T-matrix theory is able to correctly predict the time evolution of all measured light scattering quantities for all sizes of primary particles without any adjustable parameter. The structure of the aggregates, characterized by fractal dimension, d(f), was independent of the primary particle size and equal to 1.7, which is in agreement with values found in literature. Since the mean-field version of the T-matrix theory used is rather complicated and requires advanced knowledge of cluster structure (i.e., the particle-particle correlation function), a simplified version of the light scattering model was proposed and tested. It was found that within the range of operating conditions investigated, the simplified version of the light scattering model was able to describe with reasonable accuracy the time evolution of all measured light scattering quantities of the cluster mass distribution (CMD) for all three sizes of primary particles and two values of the laser wavelength. PMID:19845324

  16. Inelastic light scattering from a Mott insulator

    SciTech Connect

    Oosten, D. van; Dickerscheid, D.B.M.; Farid, B.; Stoof, H.T.C.; Straten, P. van der

    2005-02-01

    We propose to use Bragg spectroscopy to measure the excitation spectrum of the Mott-insulator state of an atomic Bose gas in an optical lattice. We calculate the structure factor of the Mott insulator taking into account both the self-energy corrections of the atoms and the corresponding dressing of the atom-photon interaction. We determine the scattering rate of photons in the stimulated Raman transition and show that by measuring this scattering rate in an experiment, in particular, the excitation gap of the Mott insulator can be determined.

  17. Molecular origin of background light in Thomson scattering measurements

    SciTech Connect

    McNeill, D.H.

    1986-06-01

    The plasma background light in Thomson scattering measurements is often far higher than expected for a pure hydrogen plasma. The spectral distribution of light from three plasmas (duration: 1 ms to steady state; electron density: below 10/sup 12/ to over 10/sup 14/ cm/sup -3/; temperature: below 20 to over 1000 eV) and signal-to-noise and intensity data from the Thomson scattering systems used on them are compared with analytic estimates to show that in two of these plasmas molecular light dominates the spectrum, while in the other, molecular light is present, but bremsstrahlung is usually more intense. Knowledge of the mechanism for background light can aid in designing detection systems for Thomson scattering and provide information on the neutral species composition and effective charge of the plasma.

  18. Circular polarization of light scattered by randomly built aggregates.

    NASA Astrophysics Data System (ADS)

    Guirado, D.; Moreno, F.; Hovenier, J. W.

    2007-06-01

    We present calculations of the scattering angle dependence of the degree of linear polarization of light singly scattered at 500 nm by randomly oriented randomly built aggregates of optically inactive homogenous identical spheres. Using the T-matrix method we analyzed the effect of changing the size of the monomers for two different geometries. The values of the computed degreee of circular polarization are comparable to the observed ones for light scattered by dust particles in comets P/Halley, C/1995 O1 (Hale-Bopp) and C/1999 S4 (LINEAR).

  19. Hybrid graphene nematic liquid crystal light scattering device.

    PubMed

    Qasim, M M; Khan, A A; Kostanyan, A; Kidambi, P R; Cabrero-Vilatela, A; Braeuninger-Weimer, P; Gardiner, D J; Hofmann, S; Wilkinson, T D

    2015-09-01

    A hybrid graphene nematic liquid crystal (LC) light scattering device is presented. This device exploits the inherent poly-crystallinity of chemical vapour deposited (CVD) graphene films to induce directional anchoring and formation of LC multi-domains. This thereby enables efficient light scattering without the need for crossed polarisers or separate alignment layers/additives. The hybrid LC device exhibits switching thresholds at very low electric fields (< 1 V μm(-1)) and repeatable, hysteresis free characteristics. This exploitation of LC alignment effects on CVD graphene films enables a new generation of highly efficient nematic LC scattering displays as well as many other possible applications. PMID:26243047

  20. Backward elastic light scattering of malaria infected red blood cells

    NASA Astrophysics Data System (ADS)

    Lee, Seungjun; Lu, Wei

    2011-08-01

    We investigated the backward light scattering pattern of healthy and malaria (Plasmodium falciparum) parasitized red blood cells. The spectrum could clearly distinguish between predominant ring stage infected blood cells and healthy blood cells. Further, we found that infected samples mixed with different stages of P. falciparum showed different signals, suggesting that even variance in parasite stages could also be detected by the spectrum. These results together with the backward scattering technique suggest the potential of non-invasive diagnosis of malaria through light scattering of blood cells near the surface of human body, such as using eyes or skin surface.

  1. Holographic light scattering in photorefractive crystals with local response

    NASA Astrophysics Data System (ADS)

    Goulkov, M.; Odoulov, S.; Woike, Th.; Imbrock, J.; Imlau, M.; Krätzig, E.; Bäumer, C.; Hesse, H.

    2002-05-01

    Strong polarization-isotropic wide-angle light scattering in photorefractive crystals with dominating photovoltaic response is explained referring to different experimental results obtained for LiTaO3:Fe crystals. It is shown experimentally that the steady-state amplification of the light scattering results from a nonzero shift in the temporal frequency between the coherent optical noise and the pump beam. Competition of photovoltaic and diffusion contributions in the photorefractive effect leads to a spatial and temporal asymmetry of nonlinear scattering. Contributions of ``hot'' electrons in the diffusion process have to be assumed.

  2. Light scattering of semitransparent sintered polytetrafluoroethylene films.

    PubMed

    Li, Qinghe; Lee, Bong Jae; Zhang, Zhuomin M; Allen, David W

    2008-01-01

    Polytetrafluoroethylene (PTFE) is a strongly scattering material and has been regarded to have optical properties similar to biological tissues. In the present study, the bidirectional reflectance distribution function (BRDF) and the bidirectional transmittance distribution function (BTDF) of several PTFE films, with thicknesses from 0.11 to 10 mm, are measured using a laser scatterometer at the wavelength of 635 nm. The directional-hemispherical reflectance (R) and transmittance (T) were obtained by integrating BRDF and BTDF for normal incidence. Comparison of the ratio of the measured R and T with that calculated from the adding-doubling method allows the determination of the reduced scattering coefficient. Furthermore, the effect of surface scattering is investigated by measuring the polarization-dependent BRDF and BTDF at oblique incidence. By analyzing the measurement uncertainty of BTDF in the near-normal observation angles at normal incidence, the present authors found that the scattering coefficient of PTFE should exceed 1200 cm(-1), which is much greater than that of biological tissues. On the other hand, the absorption coefficient of PTFE must be less than 0.01 cm(-1), much smaller than that of biological tissues, a necessary condition to achieve R > or =0.98 with a 10-mm-thick slab. PMID:19021442

  3. Fiber optic light-scattering measurement system for evaluation of embryo viability: light-scattering characteristics from live mouse embryo

    NASA Astrophysics Data System (ADS)

    Itoh, Harumi; Arai, Tsunenori; Kikuchi, Makoto

    1997-06-01

    We measured angular distribution of the light scattering from live mouse embryo with 632.8nm in wavelength to evaluate the embryo viability. We aim to measure the mitochondrial density in human embryo which have relation to the embryo viability. We have constructed the light scattering measurement system to detect the mitochondrial density non-invasively. We have employed two optical fibers for the illumination and sensing to change the angle between these fibers. There were two dips on the scattering angular distribution from the embryo. These dips existed on 30 and 85 deg. We calculated the scattering angular pattern by Mie theory to fit the measured scattering estimated scattering size and density. The best fitting was obtained when the particle size and density were 0.9 micrometers and 1010 particles per ml, respectively. These values coincided with the approximated values of mitochondrial in the embryo. The measured light scattering may mainly originated from mitochondria in spite of the existence of the various scattering particles in the embryo. Since our simple scattering measurement may offer the mitochondrial density in the embryo, it might become the practical method of human embryo on in vitro fertilization-embryo transfer.

  4. Huge light scattering from active anisotropic spherical particles.

    PubMed

    Fan, Xiaofeng; Shen, Zexiang; Luk'yanchuk, Boris

    2010-11-22

    The light scattering by a spherical particle with radial anisotropic permittivity ε and permeability μ are discussed in detail by expanding Mie theory. With the modified vector potential formulation, the electric anisotropy effects on scattering efficiency are addressed by studying the extinction, scattering, absorption and radar cross sections following the change of the transverse permittivity ε(t), the longitudinal permittivity ε(r) and the particle size q. The huge scattering cross sections are shown by considering the possible coupling between active medium and plasmon polaritons and this will be possible to result in spaser from the active plasmons of small particle. PMID:21164832

  5. Angle- and Spectral-Dependent Light Scattering from Plasmonic Nanocups

    SciTech Connect

    King, Nicholas S.; Li, Yang; Ayala-Orozco, Ciceron; Brannan, Travis; Nordlander, Peter; Halas, Naomi J.

    2011-09-27

    As optical frequency nanoantennas, reduced-symmetry plasmonic nanoparticles have light-scattering properties that depend strongly on geometry, orientation, and variations in dielectric environment. Here we investigate how these factors influence the spectral and angular dependence of light scattered by Au nanocups. A simple dielectric substrate causes the axial, electric dipole mode of the nanocup to deviate substantially from its characteristic cos² θ free space scattering profile, while the transverse, magnetic dipole mode remains remarkably insensitive to the presence of the substrate. Nanoscale irregularities of the nanocup rim and the local substrate permittivity have a surprisingly large effect on the spectral- and angle-dependent light-scattering properties of these structures.

  6. Study of Light Scattering in the Human Eye

    NASA Astrophysics Data System (ADS)

    Perez, I. Kelly; Bruce, N. C.; Valdos, L. R. Berriel

    2008-04-01

    In this paper we present a numerical model of the human eye to be used in studies of the scattering of light in different components of the eye's optical system. Different parts of the eye are susceptible to produce scattering for different reasons; age, illness or injury. For example, cataracts can appear in the human lens or injuries or fungi can appear on the cornea. The aim of the study is to relate the backscattered light, which is what doctors measure or detect, to the forward scattered light, which is what affects the patient's vision. We present the model to be used, the raytrace procedure and some preliminary results for the image on the retina without scattering.

  7. Simulation of light scattering from exoskeletons of scarab beetles.

    PubMed

    Valyukh, Sergiy; Arwin, Hans; Järrendahl, Kenneth

    2016-03-21

    An approach for simulation of light scattering from beetles exhibiting structural colors originating from periodic helicoidal structures is presented. Slight irregularities of the periodic structure in the exoskeleton of the beetles are considered as a major cause of light scattering. Two sources of scattering are taken into account: surface roughness and volume non-uniformity. The Kirchhoff approximation is applied to simulate the effect of surface roughness. To describe volume non-uniformity, the whole structure is modeled as a set of domains distributed in space in different orientations. Each domain is modeled as an ideal uniformly twisted uniaxial medium and differs from each other by the pitch. Distributions of the domain parameters are assumed to be Gaussian. The analysis is performed using the Mueller matrix formalism which, in addition to spectral and spatial characteristics, also provides polarization properties of the scattered light. PMID:27136777

  8. Polar nephelometer for light-scattering measurements of ice crystals.

    PubMed

    Barkey, B; Liou, K N

    2001-02-15

    We report on a small, lightweight polar nephelometer for the measurement of the light-scattering properties of cloud particles, specifically designed for use on a balloonborne platform in cirrus cloud conditions. The instrument consists of 33 fiber-optic light guides positioned in a two-dimensional plane from 5 degrees to 175 degrees that direct the scattered light to photodiode detectors-amplifier units. The system uses an onboard computer and data acquisition card to collect and store the measured signals. The instrument's calibration is tested by measurement of light scattered into a two-dimensional plane from small water droplets generated by an ultrasonic humidifier. Excellent comparisons between the measured water-droplet scattering properties and expectations generated by Mie calculation are shown. The measured scattering properties of ice crystals generated in a cold chamber also compare reasonably well with the theoretical results based on calculations from a unified theory of light scattering by ice crystals that use the particle size distribution measured in the chamber. PMID:18033557

  9. Wide-angle light scattering (WALS) for soot aggregate characterization

    SciTech Connect

    Oltmann, Hergen; Reimann, Joerg; Will, Stefan

    2010-03-15

    A novel set-up for the experimental determination of aggregate morphology in combustion processes based on elastic light scattering has been designed and realized. A key feature of this wide-angle light scattering (WALS) approach is an ellipsoidal mirror which is used to collect scattered light over a wide angular range of about 10-170 . The set-up employs a cw solid-state laser as light source and an intensified CCD-camera as detector. By means of the mirror the scattered light is imaged onto the detector allowing for a simultaneous acquisition of a full scattering diagram with a high angular resolution of about 0.6 . To demonstrate the performance of the approach, measurements for various sooting flames produced by premixed combustion in a flat flame burner were carried out, where the burner was operated with different equivalence ratios and fuels. It is shown that radii of gyration of soot particles may efficiently be obtained from an analysis of the scattering diagrams. (author)

  10. Surface Characterization from Doubly Scattered Light

    NASA Astrophysics Data System (ADS)

    Perez-Quintián, Fernando; Rebollo, María A.

    2004-05-01

    When a translucent diffuser is illuminated by a speckle pattern, a new speckle pattern is produced. We show that the decorrelation of this intensity pattern by displacement of the diffusing surface is related to the standard deviation of the slope's distribution when the illuminating speckle grain is chosen appropriately small. The experimental results are compared with those obtained by measuring the angular distribution of the mean scattered intensity, and they show good agreement with each other.

  11. Scattering Meters For Light In The Sea

    NASA Astrophysics Data System (ADS)

    Wells, Willard H.

    1984-09-01

    To solve radiative transfer problems in seawater, we need two inherent properties, the volume scattering function (VSF) and the absorption. The traditional direct way to obtain these quantities uses a transmissometer and a scattering meter. However, there are prob-lems with the small sample size and errors in obtaining absorption by integration of the VSF. An indirect method also shows promise. One measures the radiance field and then inverts the equations of radiative transfer to obtain the inherent properties from the apparent. The only serious shortcoming is that radiance must be a function of only one position coordinate (plus two angles). (This coordinate is depth in the case of sunlight, or distance from an isotropic lamp otherwise.) We discuss two practical implementations of this indirect approach. One would measure the radiance field with a set of fisheye cameras (following R. Smith's precedent). This very thorough method produces lots of data and requires extensive calibration and number crunching. A proposed alternate radiometer would measure certain spherical moments of the radiance field, the moments being selected to facilitate recovery of the inherent properties [Appl. Opt. 22, 2313 (Aug 83)]. This scheme would produce fewer data, but it permits recovery of absorption and moments of the VSF in (nearly) real time. Similar direct and indirect approaches apply to the measurement of very small-angle scattering, from a milliradian to a few degrees, the sort of angles that blur vision. The indirect method infers small-angle scattering from the loss of contrast in images of bar charts. In this case, the indirect method is clearly superior for the same reasons that bar charts and other test patterns are widely used (instead of point spread functions) to evaluate the performance of television and various optical systems. We built a seawater MTF meter on this principle before 1970, and its features are briefly reviewed.

  12. Scattering of light by molecules over a rough surface.

    PubMed

    Long, Maureen; Khine, Michelle; Kim, Arnold D

    2010-05-01

    We present a theory for the multiple scattering of light by obstacles situated over a rough surface. This problem is important for applications in biological and chemical sensors. To keep the formulation of this theory simple, we study scalar waves. This theory requires knowledge of the scattering operator (t-matrix) for each of the obstacles as well as the reflection operator for the rough surface. The scattering operator gives the field scattered by the obstacle due to an exciting field incident on the scatterer. The reflection operator gives the field reflected by the rough surface due to an exciting field incident on the rough surface. We apply this general theory for the special case of point scatterers and a slightly rough surface with homogeneous Dirichlet and Neumann boundary conditions. We show examples that demonstrate the utility of this theory. PMID:20448766

  13. Study on interaction between palladium(ІІ)-Linezolid chelate with eosin by resonance Rayleigh scattering, second order of scattering and frequency doubling scattering methods using Taguchi orthogonal array design

    NASA Astrophysics Data System (ADS)

    Thakkar, Disha; Gevriya, Bhavesh; Mashru, R. C.

    2014-03-01

    Linezolid reacted with palladium to form 1:1 binary cationic chelate which further reacted with eosin dye to form 1:1 ternary ion association complex at pH 4 of Walpole's acetate buffer in the presence of methyl cellulose. As a result not only absorption spectra were changed but Resonance Rayleigh Scattering (RRS), Second-order Scattering (SOS) and Frequency Doubling Scattering (FDS) intensities were greatly enhanced. The analytical wavelengths of RRS, SOS and FDS (λex/λem) of ternary complex were located at 538 nm/538 nm, 240 nm/480 nm and 660 nm/330 nm, respectively. The linearity range for RRS, SOS and FDS methods were 0.01-0.5 μg mL-1, 0.1-2 μg mL-1 and 0.2-1.8 μg mL-1, respectively. The sensitivity order of three methods was as RRS > SOS > FDS. Accuracy of all methods were determined by recovery studies and showed recovery between 98% and 102%. Intraday and inter day precision were checked for all methods and %RSD was found to be less than 2 for all methods. The effects of foreign substances were tested on RRS method and it showed the method had good selectivity. For optimization of process parameter, Taguchi orthogonal array design L8(24) was used and ANOVA was adopted to determine the statistically significant control factors that affect the scattering intensities of methods. The reaction mechanism, composition of ternary ion association complex and reasons for scattering intensity enhancement was discussed in this work.

  14. Light focusing through strongly scattering media by binary amplitude modulation

    NASA Astrophysics Data System (ADS)

    Huang, Hui-ling; Sun, Cun-zhi; Chen, Zi-yang; Pu, Ji-xiong

    2015-07-01

    Based on the angular spectrum method and the circular Gaussian distribution (CGD) model of scattering media, we numerically simulate light focusing through strongly scattering media. A high contrast focus in the target area is produced by using feedback optimization algorithm with binary amplitude modulation. It is possible to form the focusing with one focus or multiple foci at arbitrary areas. The influence of the number of square segments of spatial light modulation on the enhancement factor of intensity is discussed. Simulation results are found to be in good agreement with theoretical analysis for light refocusing.

  15. Polarized light transport in refractive weak scattering media.

    PubMed

    Soloviev, Vadim Y

    2016-07-01

    This paper is devoted to modeling of the light transport in refractive and weak scattering media by means of the vector radiative transfer equation. In refractive media polarization of light depends not only on the law of scattering but also on the refractive index distribution and can change along curved light trajectories according to the Rytov law of the polarization ellipse rotation. Results of numerical simulations are presented in the form of CCD camera images, which is how data are acquired in tomographic imaging experiments. PMID:27409689

  16. Light Scattering by Surface Tension Waves.

    ERIC Educational Resources Information Center

    Weisbuch, G.; Garbay, F.

    1979-01-01

    This simple and inexpensive experiment is an illustration of the physical concepts of interaction between light and surface tension waves, and provides a new method of measuring surface tension. (Author/GA)

  17. Comparative Study of Light Scattering from Hepatoma Cells and Hepatocytes

    NASA Astrophysics Data System (ADS)

    Lin, Xiaogang; Wang, Rongrong; Guo, Yongcai; Gao, Chao; Guo, Xiaoen

    2012-11-01

    Primary liver cancer is one of the highest mortality malignant tumors in the world. China is a high occurrence area of primary liver cancer. Diagnosis of liver cancer, especially early diagnosis, is essential for improving patients' survival. Light scattering and measuring method is an emerging technology developed in recent decades, which has attracted a large number of biomedical researchers due to its advantages, such as fast, simple, high accuracy, good repeatability, and non-destructive. The hypothesis of this project is that there may be some different light scattering information between hepatoma cells and hepatocyte. Combined with the advantages of the dynamic light scattering method and the biological cytology, an experimental scheme to measure the light scattering information of cells was formulated. Hepatoma cells and hepatic cells were irradiated by a semiconductor laser (532 nm). And the Brookhaven BI-200SM wide-angle light scattering device and temperature control apparatus were adopted. The light scattering information of hepatoma cells and hepatic cells in vitro within the 15°C to 30°C temperature range was processed by a BI-9000AT digital autocorrelator. The following points were found: (a) the scattering intensities of human hepatic cells and hepatoma cells are nearly not affected by the temperature factor, and the former is always greater than the latter and (b) the relaxation time of hepatoma cells is longer than that of hepatic cells, and both the relaxation time are shortened with increasing temperature from 15°C to 25°C. It can be concluded that hepatoma cells could absorb more incident light than hepatic cells. The reason may be that there exists more protein and nucleic acid in cancerous cells than normal cells. Furthermore, based on the length relaxation time, a conclusion can be inferred that the Brownian movement of cancer cells is greater.

  18. Noise induced in optical fibers by double Rayleigh scattering of a laser with a 1/fν frequency noise.

    PubMed

    Fleyer, Michael; Heerschap, Seth; Cranch, Geoffrey A; Horowitz, Moshe

    2016-03-15

    We study, theoretically and experimentally, intensity noise induced by double Rayleigh scattering in long optical fibers. The results of the theoretical model are compared to experimental results performed with a high-coherence-length laser with a frequency noise spectrum that is dominated by 1/fν noise. Excellent quantitative agreement between theoretical and experimental RF spectra were obtained for frequencies as low as 10 Hz and for fiber lengths between 4 and 45 km. Strong low-frequency intensity noise that is induced by 1/fν frequency noise of the laser may limit the performance of interferometric fiber optic sensors that require high-coherence-length lasers. The intensity noise due to double Rayleigh backscattering can be suppressed by reducing the coherence length of the laser. Therefore, the intensity noise has a complex and non-monotonic dependence on the 1/fν frequency noise amplitude of the laser. Stimulated Brillouin scattering will add a significant noise for input powers greater than about 7 mW for a 30 km length fiber. PMID:26977685

  19. Degree and plane of polarization of multiple scattered light. 2: Earth's atmosphere with aerosols

    NASA Technical Reports Server (NTRS)

    Plass, G. N.; Kattawar, G. W.

    1972-01-01

    The degree of polarization, as well as the direction of the plane of polarization, were calculated by a Monte Carlo method for the reflected and transmitted photons from the earth's atmosphere. The solar photons were observed during multiple collisions with aerosols and the Rayleigh scattering centers in the atmosphere. The aerosol number density, as well as the ratio of aerosol to Rayleigh scattering, varies with height. The proportion of aerosol to Rayleigh scattering was appropriately chosen at each wavelength 0.4 microns and 0.7 microns; ozone absorption was included where appropriate. Three different aerosol number densities were used to study the effects of aerosol variations. Results are given for a solar zenith angle of 81.37 deg and a surface albedo of zero. The polarization of the reflected and transmitted photons was found to be sensitive to the amount of aerosols in the atmosphere at certain angles of observation.

  20. Cell light scattering characteristic research based on FDTD algorithm

    NASA Astrophysics Data System (ADS)

    Lin, Xiaogang; Zhu, Hao; Li, Wenchao; Ye, Changbin

    2015-10-01

    As with the number of cancer increases year by year, so it is important to be found and treated earlier. With biological cells and tissues are sensitive to infrared and visible light, cell morphology and physical structure of the optical properties can easily obtain, we can provide theoretical basis for the early diagnosis of cancer by observing the difference of optical properties between normal and cancerous cells. Compared with Mie scattering theory, finite difference time domain (FDTD) algorithm can analyze any complex structure model. In this paper we use mathematical modeling method to establish the single cell mathematical model and with finite difference time domain algorithm to simulate the propagation and scattering of light in the biological cells, you can calculate the scattering of electromagnetic field distribution at anytime and anywhere. With radar cross section (RCS) to measure the results of the scattering characteristics. Due to the difference between normal cells and cancerous cells are embodied in cell shape, size and the refractive index, through the simulation we can get different cell parameters of light scattering information, Find out the cell parameters change the changing rule of the influence on the scattering characteristics and find out change regularity of scattering characteristics. These data can judge very accurate of the cells is normal or cancerous cells.

  1. Reconstruction of Rain Microstructure From Spectrum of Scattering Light

    NASA Astrophysics Data System (ADS)

    Sterlyadkin, V.; Gluschenko, A.

    Night photoregistration of light, scattered by drops had proved that practically all drops oscillate as they fall. As drop oscillation frequency W monotony diminish with drop volume V rise, so different fractions of rain form different parts of spectrum. Thereby it is possible to reconstruct rain microstructure from remote optical measure- ments. In common case the form of spectrum depends not only on drop size distri- bution N(V) but also on oscillation amplitudes function, scattering phase function for oscillating drops and on frequency dependence W(V). The statistical treatment of our field data had shown that average oscillation amplitude rise with drop volume V as , where A is a some constant. This result allows to solve the inverse problem: to re- construct drop size distribution N(V) from the power spectrum of light, scattering by rain. Scattering phase function for nonspherical and oscillating drops was calculated in straight-line approximation. Analysis of optical properties of oscillating water drop had shown some optimal measurement geometry for registration of rain microstruc- ture. For low intensity rains it is reasonable to use the effect of abnormal high modu- lation of light scattered by oscillating drops, which we discovered earlier in laboratory condition and under field measurements. (The effect of abnormal high modulation al- lows us to detect 2-3 mm raindrop deformations from 5 m distance). The results of reconstruction of drop size distributions from spectra of light, scattered by rains are presented and discussed.

  2. Transport calculations for light scattering in blood.

    PubMed Central

    Pedersen, G D; McCormick, N J; Reynolds, L O

    1976-01-01

    In vivo measurement of the oxygen saturation levels in blood may be obtained from relative amounts of backscattered monochromatic light at two different wavelengths, as measured with a fiber-optic catheter oximeter. Because of the short mean free path length of light in blood, the backscattering can be well approximated by a previously-derived, one-wavelength transport theory solution for the half-space searchlight problem. This solution, unlike simple diffusion approximations has the advantage that the boundary condition describing illumination of a localized area of blood by a monodirectional light beam can be rigorously satisfied. Sample calculations using the solution are compared with experimental values of the reflectance of blood. PMID:1252576

  3. Effects of dust particle internal structure on light scattering

    NASA Astrophysics Data System (ADS)

    Kemppinen, O.; Nousiainen, T.; Jeong, G. Y.

    2015-07-01

    There is a large variety of internal structures inside atmospheric dust particles, making them inherently inhomogeneous. Such structures may have a large effect on ground-level and atmospheric radiation. So far, dust particle internal structures and their effect on the light scattering properties have proved to be hard to quantify, in part due to challenges in obtaining information about these structures. Recently, internal structures of individual dust particles were revealed through focused ion beam milling and analyzed. Here, we perform a sensitivity study to evaluate the optical impacts of some of the typical internal structures revealed. To obtain suitable model particles, the first step is to generate inhomogeneous particles with varying internal structures by using an algorithm that is based on three-dimensional Voronoi tessellation. The parameters for the particle generation are obtained from studies of real-world Asian dust particles. The second step is to generate homogeneous versions of the generated particles by using an effective-medium approximation, for comparison. Third, light scattering by both versions of these particles is simulated with discrete-dipole approximation code. This allows us to see how different internal structures affect light scattering, and how important it is to account for these structures explicitly. Further, this allows us to estimate the potential inaccuracies caused by using only homogeneous model particles for atmospheric studies and remote sensing measurements. The results show that the effects vary greatly between different kinds of internal structures and single-scattering quantity considered, but for most structure types the effects are overall notable. Most significantly, hematite inclusions in particles impact light scattering heavily. Furthermore, internal pores and hematite-rich coating both affect some form of light scattering noticeably. Based on this work, it seems that it is exceedingly important that the

  4. Effects of dust particle internal structure on light scattering

    NASA Astrophysics Data System (ADS)

    Kemppinen, O.; Nousiainen, T.; Jeong, G. Y.

    2015-10-01

    There is a large variety of internal structures inside atmospheric dust particles, making them inherently inhomogeneous. Such structures may have a large effect on ground-level and atmospheric radiation. So far, dust particle internal structures and their effect on the light scattering properties have proved to be hard to quantify, in part due to challenges in obtaining information about these structures. Recently, internal structures of individual dust particles were revealed through focused ion beam milling and analyzed. Here, we perform a sensitivity study to evaluate the optical impacts of some of the typical internal structures revealed. To obtain suitable model particles, the first step is to generate inhomogeneous particles with varying internal structures by using an algorithm that is based on three-dimensional Voronoi tessellation. The parameters for the particle generation are obtained from studies of real-world Asian dust particles. The second step is to generate homogeneous versions of the generated particles by using an effective-medium approximation, for comparison. Third, light scattering by both versions of these particles is simulated with discrete dipole approximation code. This allows us to see how different internal structures affect light scattering, and how important it is to account for these structures explicitly. Further, this allows us to estimate the potential inaccuracies caused by using only homogeneous model particles for atmospheric studies and remote-sensing measurements. The results show that the effects vary greatly between different kinds of internal structures and single-scattering quantity considered, but for most structure types the effects are overall notable. Most significantly, hematite inclusions in particles impact light scattering heavily. Furthermore, internal pores and hematite-rich coating both affect some form of light scattering noticeably. Based on this work, it seems that it is exceedingly important that the

  5. Scattered light in the IUE spectra of Epsilon Aurigae

    NASA Technical Reports Server (NTRS)

    Aitner, B.; Chapman, R. D.; Kondo, Y.; Stencel, R. E.

    1985-01-01

    As a result of this work it was found that light scattered from the longer wavelengths constitutes a small but non-negligible, wavelength and time dependent fraction of the measured flux in the far UV. The reality of the UV excess has not been unambigiously ruled out. However, it is noted that there are still uncertainties in the assumed scattering profile. New measurements of the scattering properties of the cross disperser grating are planned in order to verify the results of Mount and Fastie and extend the wavelength coverage into the far wings of the profile. The results of these measurements will no doubt reduce some of these uncertainties. For the present, it is felt that the BCH approach is a significant improvement over the methods heretofore available for the treatment of scattered light in IUE spectra.

  6. Indigenous development of static laser light scattering (SLS) spectrometer

    NASA Astrophysics Data System (ADS)

    Joseph, David; Kumar, Amit

    2013-02-01

    An indigenous laser light scattering spectrometer is being developed for the studies of biological cells, macromolecules and their interactions. A laboratory spectrometer is used and modified as scattering arm, Turn Table and Collimating arm. Both the arms have polarizers, one acting as polarizer and the other as analyzer. The scattered light from the scattering cell is analyzed by an analyzer and is fed to a PMT and a photon counting module. Except for the PMT all the accessories are being fabricated indigenously. The studies are based initially on the studies of red blood cells. Studies are focused on for their single particle and their aggregation behavior. Using the ORT program developed by Otto Glatter the morphology of red blood cells will be analyzed.

  7. LASER BIOLOGY AND MEDICINE: Light scattering study of rheumatoid arthritis

    NASA Astrophysics Data System (ADS)

    Beuthan, J.; Netz, U.; Minet, O.; Klose, Annerose D.; Hielscher, A. H.; Scheel, A.; Henniger, J.; Müller, G.

    2002-11-01

    The distribution of light scattered by finger joints is studied in the near-IR region. It is shown that variations in the optical parameters of the tissue (scattering coefficient μs, absorption coefficient μa, and anisotropy factor g) depend on the presence of the rheumatoid arthritis (RA). At the first stage, the distribution of scattered light was measured in diaphanoscopic experiments. The convolution of a Gaussian error function with the scattering phase function proved to be a good approximation of the data obtained. Then, a new method was developed for the reconstruction of distribution of optical parameters in the finger cross section. Model tests of the quality of this reconstruction method show good results.

  8. Resonance light scattering determination of metallothioneins using levofloxacin-palladium complex as a light scattering probe

    NASA Astrophysics Data System (ADS)

    Xue, Jin-Hua; Qian, Qiu-Mei; Wang, Yong-Sheng; Meng, Xia-Ling; Liu, Lu

    2013-02-01

    A novel method of resonance light scattering (RLS) was developed for the analysis of trace metallothioneins (MTs) in human urine. In a CH3COOH-CH3COONa buffer solution of pH 4.5, the formation of a complex between levofloxacin (LEV)-Pd and MTs led to enhance the RLS intensity of the system, and the enhanced RLS intensity at 468 nm was proportional to the concentration of MTs in the range of 0.059-22.4 μg mL-1. The linear regression equation was ΔI = 127.5 ρ (μg mL-1)-88.02 with a correlation coefficient of 0.9992, and the detection limit of 17.8 ng mL-1. The relative standard deviation and the average recovery were 3.8-5.4% (n = 11) and 92.15%, respectively. The proposed method is convenient, reliable and sensitive, and has been used successfully for the determination of trace MTs in human urine samples.

  9. An experimental study of light scattering by large, irregular particles

    NASA Technical Reports Server (NTRS)

    Mcguire, Audrey F.; Hapke, Bruce W.

    1995-01-01

    The intensity and polarization of light scattered by a variety of types of artificial partices large compared to the wavelength were measured as a function of phase angle. Shape, surface roughness, absorption coefficient, and internal scattering coefficient were varied systematically and their effects studied. Scattering by clear, smooth-surfaced spheres is in quantitative agreement with the predictions of the geometrical optics (ray theory) approximation to physical optics (Mie theory). The phase functions of almost all of the particles measured have both forward and backward scattering lobes. A two-parameter, double Henyey-Greenstein function generally provides reasonably good descriptions of the data, while keeping the number of free parameters to the minimum necessary. On a double Henyey- Greenstein parameter plot all of the particles fall into an L-shaped area of restricted size in which the location is characteristic of the particle type. Formalisms based on the equivalent slab model are also given for estimating the scattering efficiency of a large, irregular particle. For most dielectric particles the transmitted, forward scattered light is partially negatively polarized. It is this component that is respopnsible for the well-known maximum in the polarization curves of planetary regoliths at phase angles around 100 deg. For phase angles between about 30 deg and 70 deg the internally scattered light is found to be randomly polarized in the particles studied here, so that the only contribution to the second component of the Stokes vector is by Fresnel reflection from the particle surface. If this empirical result is general, measurement of the second Stokes vector of the light scattered from a regolith at these angles may provide a method of remotely measuring the mean refractive index.

  10. Scattering of non-separable states of light

    NASA Astrophysics Data System (ADS)

    Perumangatt, Chithrabhanu; Salla, Gangi Reddy; Anwar, Ali; Aadhi, A.; Prabhakar, Shashi; Singh, R. P.

    2015-11-01

    We experimentally show that the non-separability of polarization and orbital angular momentum present in a light beam remains preserved under scattering through a random medium like rotating ground glass. We verify this by measuring the degree of polarization and observing the intensity distribution of the beam when projected to different polarization states, before as well as after the scattering. We extend our study to the non-maximally non-separable states also.

  11. Neutron and light scattering studies of light-harvesting photosynthetic antenna complexes

    SciTech Connect

    Tang, Kuo-Hsiang; Blankenship, Robert E.

    2011-06-28

    Small-angle neutron scattering (SANS) and dynamic light scattering (DLS) have been employed in studying the structural information of various biological systems, particularly in systems without high-resolution structural information available. In this report, we briefly present some principles and biological applications of neutron scattering and DLS, compare the differences in information that can be obtained with small-angle X-ray scattering (SAXS), and then report recent studies of SANS and DLS, together with other biophysical approaches, for light-harvesting antenna complexes and reaction centers of purple and green phototrophic bacteria.

  12. Inferring mixture Gibbs free energies from static light scattering data

    NASA Astrophysics Data System (ADS)

    Ross, David; Wahle, Christopher; Thurston, George

    We describe a light scattering partial differential equation for the free energy of mixing that applies to connected, isotropic ternary and quaternary liquid composition domains, including restricted domains which may not touch all binary axes. For restricted domains, contrasting light scattering efficiency patterns obtained at different wavelengths can correspond to the same underlying free energy, and supplement the available information. We discuss well-posed problems for this fully nonlinear, degenerate elliptic partial differential equation. Using Monte Carlo simulations, we provide estimates of the overall system measurement time and sample spacing needed to determine the free energy to a desired degree of accuracy, and indicate how measurement time depends on instrument throughput. These methods provide a way to use static light scattering to measure, directly, mixing free energies of many systems that contain liquid domains. Supported by NIH EY018249.

  13. Diffusion of interacting particles: light scattering study of microemulsions

    SciTech Connect

    Cazabat, A.M.; Langevin, D.

    1981-03-15

    The diffusion coefficient data obtained from light scattering experiments on water-in-oil microemulsions have been compared with existing theoretical treatments involving the interaction potential. The observed behavior deviates largely from hard sphere systems and independent information was obtained about the interaction potential to check the theories. This was achieved by measuring simultaneously the intensity and the correlation function of the scattered light. The intensity has been analyzed with a very simple model for interaction forces involving only 2 parameters: a hard sphere radius and the amplitude of a small perturbation added to hard sphere potential. This model allows for the variation of the diffusion coefficient at small volume fractions. Light scattering techniques are a very useful method for obtaining information about sizes and interactions in microemulsions. Some general conclusions have been made: droplet sizes depend mostly on the ratio of water to soap, and interactions on continuous phase polarity and alcohol chain length.

  14. Laser light scattering as a probe of fractal colloid aggregates

    NASA Technical Reports Server (NTRS)

    Weitz, David A.; Lin, M. Y.

    1989-01-01

    The extensive use of laser light scattering is reviewed, both static and dynamic, in the study of colloid aggregation. Static light scattering enables the study of the fractal structure of the aggregates, while dynamic light scattering enables the study of aggregation kinetics. In addition, both techniques can be combined to demonstrate the universality of the aggregation process. Colloidal aggregates are now well understood and therefore represent an excellent experimental system to use in the study of the physical properties of fractal objects. However, the ultimate size of fractal aggregates is fundamentally limited by gravitational acceleration which will destroy the fractal structure as the size of the aggregates increases. This represents a great opportunity for spaceborne experimentation, where the reduced g will enable the growth of fractal structures of sufficient size for many interesting studies of their physical properties.

  15. Light scattering study of enzymatic degradation of polyurethane

    NASA Astrophysics Data System (ADS)

    Himel, Denny; Norwood, David; Howard, Gary

    2000-11-01

    It is known that naturally occurring enzymes produced by members of the genus Pseudomonas hydrolytically degrade synthetic polyesterurethanes. Enzymes from the three species Pseudomonas fluorescens, Pseudomonas clororaphis and Comamonas acidovarans have been isolated and show hydrolytic activity. Further, it has been shown that static laser light scattering, in both batch mode (SLS) and time resolved (TRSLS), is a technique effective in characterizing systems undergoing enzymatic degradation. A general theory of TRSLS is summarized. This theory is then used when we employ static laser light scattering (SLS) to carefully characterize both the high molecular weight polyurethane substrate and the isolated enzymes, and time resolved static laser light scattering (TRSLS) to determine the absolute rate of degradation and to characterize the mechanism of enzymes isolated from bacteria mentioned above.

  16. Scattered light in the IUE spectra of Epsilon Aurigae

    NASA Technical Reports Server (NTRS)

    Altner, B.; Chapman, R. D.; Kondo, Y.; Stencel, R. E.

    1986-01-01

    Recent infrared photometry indicates that the alleged disk of particulate matter surrounding the mysterious secondary object in the Epsilon Aur system is cold, around 500 K. IUE spectra, on the other hand, contain significant flux in excess of that expected from an F0 Ia star in the far UV, which if interpreted as a hot secondary star leads to a possible contradiction with the IR data. Other models of the UV excess have been proposed, including the idea that the bulk of the short-wavelength flux is light scattered into the SWP camera from longer wavelengths. With the recent availability of a detailed generalized IUE descattering algorithm it is possible to thoroughly investigate the scattered-light contribution to the short-wavelength continuum. It is found that the IUE spectra are indeed partially contaminated by scattered light, but that even after correction for this instrumental effect a significant time-dependent UV excess is still present.

  17. Additivity of light-scattering patterns of aggregated biological particles

    NASA Astrophysics Data System (ADS)

    Moskalensky, Alexander E.; Strokotov, Dmitry I.; Chernyshev, Andrei V.; Maltsev, Valeri P.; Yurkin, Maxim A.

    2014-08-01

    The paper is focused on light scattering by aggregates of optically soft particles with a size larger than the wavelength, in particular, blood platelets. We conducted a systematic simulation of light scattering by dimers and larger aggregates of blood platelets, each modeled as oblate spheroids, using the discrete dipole approximation. Two-dimensional (2-D) light scattering patterns (LSPs) and internal fields showed that the multiple scattering between constituent particles can be neglected. Additionally, we derived conditions of the scattering angle and orientation of the dimer, under which the averaging of the 2-D LSPs over the azimuthal scattering angle washes out interference in the far field, resulting in averaged LSPs of the aggregate being equal to the sum of that for its constituents. We verified theoretical conclusions using the averaged LSPs of blood platelets measured with the scanning flow cytometer (SFC). Moreover, we obtained similar results for a model system of aggregates of polystyrene beads, studied both experimentally and theoretically. Finally, we discussed the potential of discriminating platelet aggregates from monomers using the SFC.

  18. Novel Trapping and Scattering of Light in Resonant Nanophotonic Structures

    NASA Astrophysics Data System (ADS)

    Hsu, Chia Wei

    Nanophotonic structures provide unique ways to control light and alter its behaviors in ways not possible in macroscopic structures. In this thesis, we explore novel behaviors of light created by nanophotonic structures, with a common theme on resonance effects. The first half of the thesis focuses on a peculiar type of electromagnetic resonance, where the resonance lifetime diverges to infinity. These states, called bound states in the continuum, remain localized in space even though their frequency lie within a continuum of extended modes. We find such states in photonic crystal slabs and the surface of bulk photonic crystals. We show the conditions necessary for them to exist, and provide the first experimental observation of these unusual states. We also show that these states have a topological nature, with conserved and quantized topological charges that govern their generation, evolution, and annihilation. The second half of the thesis concerns light scattering from resonant nanophotonic structures, where resonances can enhance or suppress scattering at particular wavelengths and angles. We show that multiple resonances in one nanostructure and in the same multipole channel generally lead to a scattering dark state where the structure becomes transparent. Based on the coherent interference from multiple scatterers, we show there are geometries that can achieve a sharp structural color where the hue, saturation, and brightness are all viewing-angle independent. We also invent a new type of transparent display based on wavelength-selective light scattering from nanostructures.

  19. Forward-scattered light: Spectral broadening and temporal coherence

    NASA Astrophysics Data System (ADS)

    Swanson, N. L.; van Winkle, D. H.

    1997-06-01

    Fabry-Pérot spectroscopy was used to observe a spectral broadening of 1.3+/-0.2 MHz in laser light forward scattered through a colloidal solution. Light from a single-mode argon-ion laser was collected after scattering through water to which measured amounts of diatomaceous earth or 0.08-μm-diam polystyrene spheres were successively added. The broadening is attributed to coupling between fluctuations in particle concentration and spontaneous thermal fluctuations. Though spontaneous fluctuations exist in all pure fluids, they are very weak in water. However, the presence of the particles induces temperature gradients in the fluid, which in turn induce fluctuations in particle concentration.

  20. Coherent anti-Stokes Raman scattering imaging under ambient light.

    PubMed

    Zhang, Yinxin; Liao, Chien-Sheng; Hong, Weili; Huang, Kai-Chih; Yang, Huaidong; Jin, Guofan; Cheng, Ji-Xin

    2016-08-15

    We demonstrate an ambient light coherent anti-Stokes Raman scattering microscope that allows CARS imaging to be operated under environmental light for field use. The CARS signal is modulated at megahertz frequency and detected by a photodiode equipped with a lab-built resonant amplifier, then extracted through a lock-in amplifier. The filters in both the spectral domain and the frequency domain effectively blocked the room light contamination of the CARS image. In situ hyperspectral CARS imaging of tumor tissue under ambient light is demonstrated. PMID:27519113

  1. Investigation of light scattering on a single dust grain

    NASA Astrophysics Data System (ADS)

    Pavlu, Jiri; Nemecek, Zdenek; Safrankova, Jana; Barton, Petr

    2016-07-01

    Complex phenomenon of light scattering by dust grains plays an important role in all dust--light interactions, especially in space, e.g., light passing through dense dusty clouds in the space as well as in the upper atmosphere, dust charging by photoemission, etc. When the wavelength of the incident light is about the size of the grain, the Mie theory is often used to characterize the scattering process. Unfortunately, we have only very limited knowledge of necessary material constants for most of the space-related materials and also the solution of Mie equations for general grain shapes is difficult or unknown. We develop an apparatus for observations of light scattering on small (micrometer-sized) arbitrary shaped dust grains. We directly measure the scattering by levitating grains in the field created by the standing-wave ultrasonic trap, where we can study single grains or small grain clusters. The experiment is performed at atmospheric air --- unlike other experiments, where grains were measured in water or other liquids. Therefore, the background effects are significantly reduced. Currently, the trap is under development and first tests are carried out. Besides initial results, we focus on theoretical computations of the ultrasonic field of the selected trap.

  2. Study of resonance light scattering for remote optical probing

    NASA Technical Reports Server (NTRS)

    Penney, C. M.; Morey, W. W.; St. Peters, R. L.; Silverstein, S. D.; Lapp, M.; White, D. R.

    1973-01-01

    Enhanced scattering and fluorescence processes in the visible and UV were investigated which will enable improved remote measurements of gas properties. The theoretical relationship between scattering and fluorescence from an isolated molecule in the approach to resonance is examined through analysis of the time dependence of re-emitted light following excitation of pulsed incident light. Quantitative estimates are developed for the relative and absolute intensities of fluorescence and resonance scattering. New results are obtained for depolarization of scattering excited by light at wavelengths within a dissociative continuum. The experimental work was performed in two separate facilities. One of these utilizes argon and krypton lasers, single moded by a tilted etalon, and a 3/4 meter double monochromator. This facility was used to determine properties of the re-emission from NO2, I2 and O3 excited by visible light. The second facility involves a narrow-line dye laser, and a 3/4 meter single monochromator. The dye laser produces pulsed light with 5 nsec pulse duration and 0.005 nm spectral width.

  3. Bulk and surface light scattering from transparent silica aerogel

    NASA Astrophysics Data System (ADS)

    Platzer, Werner J.; Bergkvist, Mikael

    1992-11-01

    Elastic light scattering has been used to study structural properties of different transparent aerogels, which may be used as filling materials in super-windows. With a goniometer having an angular resolution better than 0.6 degree(s) and a He-Ne laser as the light source we investigated the angular distribution of scattered intensity from transparent silica aerogels and one xerogel. The densities ranged between 0.11 and 0.60 gcm-3. An exponential correlation function for the density fluctuations of a random porous medium has been utilized to analyze the large-angle scattering, which is dominated by bulk scattering, for different polarization of the incident light. The determination of correlation lengths in the nanometer range was possible, because the absolute scattering intensities were determined. For relative angular dependence measurements, this range would have been accessible only to small angle x-ray scattering (SAXS). The resulting mean pore sizes between 8 nm and 50 nm and specific surface areas between 500 and 700 m2/g agree well with nitrogen-porosimetry data from the literature. The data compare quite well with correlation lengths calculated from specular transmittance data from an ordinary spectrophotometer. This method, which is not sensitive to the angular distribution of superposed forward scattering with large correlation lengths, has also been applied to a series of base-catalyzed TMOS aerogels with different catalyst concentrations. The forward scattering peak of the signal may be attributed to correlation lengths in the micrometer range. Experimental results for aerogel surfaces with evaporated aluminum indicate that this might be due to the surface properties. A quantitative analysis, however, is not possible yet.

  4. Light scattering by ensemble of nonabsorbing correlated two-layered particles: specific feature for spectral dependence of extinction coefficient.

    PubMed

    Berdnik, Vladimir V; Loiko, Valery A

    2011-08-01

    Scattering of light by an ensemble of nonabsorbing spherical concentric two-layered particles is considered. It has been shown that exponent of the power function describing the wavelength dependence of the extinction coefficient of the medium with subwavelength-sized particles can exceed considerably the value of 4, which takes place for the Rayleigh scattering. Spatial correlation of particles enhances this "anomalous" dependence on the wavelength. Bleaching and darkening effects can be implemented. In the first case transmittance increases, while in the second case transmittance decreases with increased volume concentration. These effects can be used to get a sharp spectral dependence of transmittance. Comparison with the data for spatially correlated homogeneous particles is carried out. PMID:21833095

  5. Towards determination of absolute molar mass of cellulose polymer by size exclusion chromatography with mulitple angle laser light scattering detection.

    PubMed

    Pawcenis, Dominika; Thomas, Jacob L; Łojewski, Tomasz; Milczarek, Jakub M; Łojewska, Joanna

    2015-08-28

    The study focuses on determination of a set of crucial parameters for molar mass calculation of cellulose from the results of size exclusion chromatography coupled with multiple angle laser light scattering (MALLS) and differential refractive index (DRI) detectors. In the present work, cellulose has been derivatised to obtain cellulose tricarbanilate (CTC) soluble in tetrahydrofuran (THF). The parameters of Rayleigh scattering in the MALLS detector: refractive index increment (dn/dc) and second virial coefficient (A2) of CTC in THF were determined for laser wavelength 658nm. In order to avoid errors resulting from cellulose derivatisation by-products present in the CTC solution, the so called "on-line" method of measuring dn/dc and A2 was applied. Based on the A2 determination, its influence on cellulose molar mass calculations and cellulose molecular dimensions were critically assessed. The latter includes evaluation of artificially aged cellulose towards conceivable branching by conformation plot analysis. PMID:26210115

  6. Wavelet transform fast inverse light scattering analysis for size determination of spherical scatterers

    PubMed Central

    Ho, Derek; Kim, Sanghoon; Drake, Tyler K.; Eldridge, Will J.; Wax, Adam

    2014-01-01

    We present a fast approach for size determination of spherical scatterers using the continuous wavelet transform of the angular light scattering profile to address the computational limitations of previously developed sizing techniques. The potential accuracy, speed, and robustness of the algorithm were determined in simulated models of scattering by polystyrene beads and cells. The algorithm was tested experimentally on angular light scattering data from polystyrene bead phantoms and MCF-7 breast cancer cells using a 2D a/LCI system. Theoretical sizing of simulated profiles of beads and cells produced strong fits between calculated and actual size (r2 = 0.9969 and r2 = 0.9979 respectively), and experimental size determinations were accurate to within one micron. PMID:25360350

  7. Visualizing Light Scattering in Silicon Waveguides with Black Phosphorus Photodetectors.

    PubMed

    Wang, Tianjiao; Hu, Shuren; Chamlagain, Bhim; Hong, Tu; Zhou, Zhixian; Weiss, Sharon M; Xu, Ya-Qiong

    2016-09-01

    A black phosphorus photodetector is utilized to investigate the light-scattering patterns of a silicon waveguide through wavelength- and polarization-dependent scanning photocurrent measurements. The photocurrent signals exhibit similar patterns to the light-intensity distribution of the waveguide calculated by finite-difference time-domain simulations, suggesting that photoexcited electron-hole pairs in the silicon waveguide can be injected into phosphorene to induce its photoresponse. PMID:27296253

  8. Dispersion relation for hadronic light-by-light scattering

    NASA Astrophysics Data System (ADS)

    Procura, Massimiliano; Colangelo, Gilberto; Hoferichter, Martin; Stoffer, Peter

    2016-04-01

    The largest uncertainties in the Standard Model calculation of the anomalous magnetic moment of the muon (g - 2)μ come from hadronic contributions. In particular, in a few years the subleading hadronic light-by-light (HLbL) contribution might dominate the theory uncertainty. We present a dispersive description of the HLbL tensor, which is based on unitarity, analyticity, crossing symmetry, and gauge invariance. This opens up the possibility of a data-driven determination of the HLbL contribution to (g - 2)μ with the aim of reducing model dependence and achieving a reliable error estimate. Our dispersive approach defines unambiguously the pion-pole and the pion-box contribution to the HLbL tensor. Using Mandelstam's double-spectral representation, we have proven that the pion-box contribution coincides exactly with the one-loop scalar QED amplitude, multiplied by the appropriate pion vector form factors.

  9. Effects of acetic acid on light scattering from cells

    PubMed Central

    Marina, Oana C.; Sanders, Claire K.

    2012-01-01

    Abstract. Acetic acid has been used for decades as an aid for the detection of precancerous cervical lesions, and the use of acetic acid is being investigated in several other tissues. Nonetheless, the mechanism of acetowhitening is unclear. This work tests some of the hypotheses in the literature and measures changes in light scattering specific to the nucleus and the cytoplasm. Wide angle side scattering from both the nucleus and the cytoplasm increases with acetic application to tumorigenic cells, with the increase in nuclear scattering being greater. In one cell line, the changes in nuclear scattering are likely due to an increase in number or scattering efficiency of scattering centers smaller than the wavelength of excitation light. There are likely several cellular changes that cause acetowhitening and the cellular changes may differ with cell type. These results should lead to a better understanding of acetowhitening and potentially the development of adjunct techniques to improve the utility of acetic acid application. For the well-studied case of cervical tissue, acetowhitening has been shown to be sensitive, but not specific for oncogenic changes needing treatment. PMID:23224185

  10. The impact of dust particle morphological details on light scattering

    NASA Astrophysics Data System (ADS)

    Kemppinen, Osku; Nousiainen, Timo; Lindqvist, Hannakaisa; Jeong, Gi Young

    2016-04-01

    We investigate the impact of dust particle surface roughness and internal structure on light scattering. Starting from digital representation of realistically shaped dust particles, we vary the particle morphology, and perform light scattering simulations to both the original and the modified particles. By mapping the changes in morphology to the changes in scattering, we will get information of how strongly and in which way a particular change affects scattering. All investigations have been done with complex, irregular particle shapes. For surface roughness studies we have kept the particle total volume virtually constant during the roughening process, and the roughness element size small enough to keep the overall shape relatively unchanged. For internal structure studies, the size and the external shape are kept constant. These safety measures help ensure that the effects seen are in fact due to the feature studied. The work is notable for model development, because some models can not include surface roughness, for example. In that case, the people who use such models have to adjust for the fact that the results are inaccurate, and by knowing how surface roughness typically changes the scattering results, the adjustment can be made. As a corollary, if it is shown that a particular feature does not change scattering results in any noticeable way, the model developers can confidently ignore or simplify it.

  11. Quasi-elastic light scattering in betaine calcium chloride dihydrate (BCCD)

    NASA Astrophysics Data System (ADS)

    Schmitt-Lewen, M.; Schaack, G.

    1999-12-01

    We report measurements of the temperature (40 Kicons/Journals/Common/le" ALT="le" ALIGN="TOP"/> T icons/Journals/Common/le" ALT="le" ALIGN="TOP"/>200 K) and polarization (z(yy)x,z(xz)x) dependence of the integrated intensities of quasi-elastically scattered laser light (icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/> = 514.5 nm) in a wavenumber interval of 0+/-3 cm-1 around the Rayleigh line at the different phase transitions in single crystals of BCCD. Large anomalies (central peaks) are observed at the transitions into the ferroelectric, the various commensurate (c,c´), and the incommensurate phases. The widths of the anomalies on the temperature scale are large in the regions of quasi-harmonic modulation of the structure, but narrow and distinct in the region of square-wave modulation in the solitonic phase of BCCD, where also unusual shapes on the T-axis are observed. The scattering phenomena at low temperatures are interpreted hypothetically as due to fluctuations caused by the formation or rearrangement of domain walls (solitons) in the lattice near the transitions between commensurate phases and by the variation in soliton density. The cicons/Journals/Common/leftrightarrow" ALT="leftrightarrow" ALIGN="TOP"/>c´ transitions are of the order-disorder type.

  12. Tomographic retrieval for scattered light limb measurements: multiple spectral fit windows to improve the spatial resolution

    NASA Astrophysics Data System (ADS)

    Pukite, Janis; Dörner, Steffen; Wagner, Thomas

    2015-04-01

    The Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) on the ENVISAT satellite probed the atmosphere at the day side of Earth in alternating sequences of nadir and limb measurements from August 2002 to April 2012. Limb measurements allow the retrieval of stratospheric profiles of various trace gases on a global scale. It has been shown that combining measurements of the same air volume from different viewing positions along the orbit, 2D distribution fields of stratospheric trace gases can be acquired in one inversion step. Since the atmospheric scattering and absorption processes are wavelength dependent, the spatial sensitivity for limb observations also varies with wavelength. In general, for longer wavelengths, photons from more remote areas along the line of sight are contributing stronger to the measurement than for shorter wavelengths because of the lower probability of Rayleigh scattering. In addition, the radiative transfer is modified by the ozone absorption structures making longer light paths less probable within strong ozone absorption bands. In this study, additional information on the spatial distribution of NO2 is investigated by analysing results obtained by Differential Optical Absorption Spectroscopy (DOAS) in various spectral fit windows. Combing the fit results in one profile retrieval algorithm helps to improve the spatial sensitivity and resolution of the measurements. The largest improvements for the spatial resolution and sensitivity are expected for the upper troposphere/ lower stratosphere (UTLS) region where the variation of the spatial sensitivity with wavelength is strongest.

  13. Circular polarization of light scattered by asymmetrical particles

    NASA Astrophysics Data System (ADS)

    Guirado, D.; Hovenier, J. W.; Moreno, F.

    2007-07-01

    We present calculations of the degree of circular polarization of light singly scattered by some kinds of asymmetrical particles in random orientation as a function of the scattering angle, using the T-matrix method. To clarify the possible contribution of asymmetry of particles to circular polarization we considered aggregates of optically inactive homogeneous identical spheres. We analysed the effect of changing the size of the monomers and the refractive index. We also performed calculations for two different geometries. The values of the computed degree of circular polarization are generally in the range of the observed ones for light scattered by dust particles in comets P/Halley, C/1995 O1 (Hale-Bopp) and C/1999 S4 (LINEAR), in the interplanetary medium and in the interstellar medium of our galaxy.

  14. Light scattering by nonspherical particles: some practical aspects

    NASA Astrophysics Data System (ADS)

    Farafonov, Victor G.; Il'in, Vladimir; Voshchinnikov, Nikolai V.; Prokopjeva, M. S.

    2005-03-01

    Real scatterers are known to usually have complex shape and some structure. Therefore, to perform light scattering simulations, one should specify their models and select proper computational methods. To help in solution of these problems, we have created an internet cite DOP (Database of Optical Properties of non-spherical particles). The currnet content of the DOP (optical constants, reviews and bibliographies, codes, etc.) is briefly described. A special attention is paid to recently developed fast methods and codes to treat light scattering by non-spherical inhomogeneous particles using the layered models. First results of application of these tools to comparable study of the optical properties of layered particles and particles with inclusions are presented.

  15. Debye series for light scattering by a multilayered sphere.

    PubMed

    Li, Renxian; Han, Xiange; Jiang, Huifen; Ren, Kuan Fang

    2006-02-20

    We have derived the formula for the Debye-series decomposition for light scattering by a multilayered sphere. This formulism permits the mechanism of light scattering to be studied. An efficient algorithm is introduced that permits stable calculation for a large sphere with many layers. The formation of triple first-order rainbows by a three-layered sphere and single-order rainbows and the interference of different-order rainbows by a sphere with a gradient refractive index, are then studied by use of the Debye model and Mie calculation. The possibility of taking only one single mode or several modes for each layer is shown to be useful in the study of the scattering characteristics of a multilayered sphere and in the measurement of the sizes and refractive indices of particles. PMID:16523791

  16. A Study of Brownian Motion Using Light Scattering

    ERIC Educational Resources Information Center

    Clark, Noel A.; And Others

    1970-01-01

    Presents an advanced laboratory experiment and lecture demonstration by which the intensity spectrum of light scattered by a suspension of particles in a fluid can be studied. From this spectrum, it is possible to obtain quantitative information about the motion of the particles, including an accurate determination of their diffusion constant.…

  17. Light Scattering by Polymers: Two Experiments for Advanced Undergraduates.

    ERIC Educational Resources Information Center

    Matthews, G. P.

    1984-01-01

    Background information, procedures, equipment, and results for two experiments are presented. The first involves the measurement of the mass-average and degree of coiling of polystyrene and is interpreted by the full mathematical theory of light scattering. The second is the study of transitions in gelatin. (JN)

  18. Angular and spectral light scattering from complex multidielectric coatings

    NASA Astrophysics Data System (ADS)

    Grèzes-Besset, Catherine; Torricini, Didier; Krol, Hélène; Zerrad, Myriam; Lequime, Michel; Amra, Claude

    2011-09-01

    Due to the improvement of deposition technologies and polishing techniques, light scattering has been considerably reduced in optical coatings these last decades, with the result of high quality dense optical filters with minimal losses. However such improvements coupled with modern monitoring techniques have also allowed designing and producing more complex coatings with layer numbers exceeding several hundred in some situations. Within this framework light scattering must again be revisited and analysed in detail, including global loss levels together with angular and spectral analysis. This paper is devoted to the optical balance of sophisticated components for Earth Observation, where the same scene is observed simultaneously in several adjacent wavebands. Self-blocking multilayer stacks are involved to eliminate out-of band harmonics in the instrument but the filter performances are degraded due to an increase of cross talk originating from light scattering. To address this problem we use the theories of light scattering from surface roughness and bulk heterogeneity, which allows to quantity cross-talk levels and choose more adequate filters. A special emphasis is given to the case of hyperspectral filters assemblies located in the focal plane for image filtering.

  19. OLIGOMERIZATION STATE OF RUBISCO ACTIVASE REVEALED BY DYNAMIC LIGHT SCATTERING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The self-association of Rubisco activase has been suggested to be required for Rubisco activation via ATP hydrolysis. To study the oligmerization patterns in detail, we initially measured the size of each isoform (42 KDa and 45 KDa) of recombinant spinach activase using dynamic light scattering spec...

  20. Incorporation of flow injection analysis with dual-wavelength overlapping resonance Rayleigh scattering for rapid determination of malachite green and its metabolite in fish

    NASA Astrophysics Data System (ADS)

    Zhu, Jinghui; Qin, Mingyou; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli

    2014-09-01

    A flow injection analysis (FIA) system combined with dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) has been established and validated for rapid determination of malachite green (MG) and its metabolite in fish samples. Under experimental condition, MG would react with Erythrosin (Ery) to form ion-association complexes, resulting in the occurrence of two RRS peaks and a dramatic enhancement of RRS intensity. The maximum RRS peaks were located at 286 nm and 337 nm. It is noted that the increments of both of these two peaks were proportional to the concentration of MG. The detection limit of DWO-RRS was 1.5 ng/mL, which was comparable to several reported methods. Moreover, the results of real sample analysis exhibited an acceptable recovery between 97.5% and 103.6%, indicating that the method had good reproducibility.

  1. HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Sing, D. K.; Wakeford, H. R.; Showman, A. P.; Nikolov, N.; Fortney, J. J.; Burrows, A. S.; Ballester, G. E.; Deming, D.; Aigrain, S.; Désert, J.-M.; Gibson, N. P.; Henry, G. W.; Knutson, H.; Lecavelier des Etangs, A.; Pont, F.; Vidal-Madjar, A.; Williamson, M. W.; Wilson, P. A.

    2015-01-01

    We present Hubble Space Telescope optical and near-IR transmission spectra of the transiting hot-Jupiter WASP-31b. The spectrum covers 0.3-1.7 μm at a resolution R ˜ 70, which we combine with Spitzer photometry to cover the full-optical to IR. The spectrum is dominated by a cloud deck with a flat transmission spectrum which is apparent at wavelengths > 0.52 μm. The cloud deck is present at high altitudes and low pressures, as it covers the majority of the expected optical Na line and near-IR H2O features. While Na I absorption is not clearly identified, the resulting spectrum does show a very strong potassium feature detected at the 4.2σ confidence level. Broadened alkali wings are not detected, indicating pressures below ˜10 mbar. The lack of Na and strong K is the first indication of a sub-solar Na/K abundance ratio in a planetary atmosphere (ln[Na/K] = -3.3 ± 2.8), which could potentially be explained by Na condensation on the planet's night side, or primordial abundance variations. A strong Rayleigh scattering signature is detected at short wavelengths, with a 4σ significant slope. Two distinct aerosol size populations can explain the spectra, with a smaller sub-micron size grain population reaching high altitudes producing a blue Rayleigh scattering signature on top of a larger, lower lying population responsible for the flat cloud deck at longer wavelengths. We estimate that the atmospheric circulation is sufficiently strong to mix micron size particles upwards to the required 1-10 mbar pressures, necessary to explain the cloud deck. These results further confirm the importance of clouds in hot Jupiters, which can potentially dominate the overall spectra and may alter the abundances of key gaseous species.

  2. Resonating Rays in Light Ion Scattering from AN Optical Potential.

    NASA Astrophysics Data System (ADS)

    Stoyanov, Basil John

    Recent experimental investigations reveal that resonances of composite ion-ion systems are a general phenomenon in light- and heavy-ion scattering. The experimentally observed phenomenon known as the anomalous large-angle scattering (ALAS) of alpha-particle from certain isotopes, such as (alpha)-('40)Ca, manifests itself in the form of successive peaks in the back-scattering excitation function. Earlier theoretical studies were mainly concentrated either on the surface-wave or geometrical-wave description of these phenomena, whereas the pont of view taken here, which is based on the results of physical acoustics, is that the ion-ion scattering amplitude contains both the surface-wave and the geometrical-wave contributions. Therefore a comprehensive approach would be to investigate both of these contributions simultaneously. This is achieved in the present work through a decomposition, by applying the Sommerfeld-Watson and Imai transformations, of the scattering amplitude into its ingredients and by analyzing both the resulting geometrical rays and the surface waves in terms of resonances. This procedure generates a precise mathematical description of resonance processes in ion scattering (via the S-function poles) and at the same time leads in a semi -classical framework to their thorough physical interpretation (via the generalized Bohr-Sommerfeld quantization condition). The existence of resonances in both the geometrical and surface waves emerges from such a description, and is exemplified by numerical calculations for (alpha)-('40)Ca elastic scattering.

  3. Unitary and reciprocal expansions in the theory of light scattering from a grating

    NASA Astrophysics Data System (ADS)

    Brown, G. C.; Celli, V.; Coopersmith, M.; Haller, M.

    1983-07-01

    We present a method of obtaining coupled integral equations for the scattering of scalar waves from a rough surface of a medium characterized by a dielectric constant ɛ. These equations, obtained by applying Rayleigh's method, are useful for generating approximate solutions which are both unitary and reciprocal. We examine in particular the scattering of p and s polarized electromagnetic waves from a one-dimensional profile.

  4. Multipolar polarizations of methane from isotropic and anisotropic collision-induced light scattering

    SciTech Connect

    Bancewicz, T.; Nowicka, K.; Godet, J.-L.; Le Duff, Y.

    2004-06-01

    The anisotropic and isotropic binary collision-induced spectra scattered by gaseous methane have been measured in absolute units up to 900 cm{sup -1} from the Rayleigh line. Corresponding theoretical intensities taking into account multipolar polarizabilities have been calculated using a semiclassical procedure. From the analysis of, mainly, our isotropic scattering data, values of the dipole-quadrupole and dipole-octopole polarizabilities are deduced. They are found to be in good agreement with recent ab initio calculations.

  5. Free-form thin lens design with light scattering surfaces for practical LED down light illumination

    NASA Astrophysics Data System (ADS)

    Lin, Raychiy J.; Sun, Ching-Cherng

    2016-05-01

    The free-form optical quasilens surface technology was utilized to develop and design a solid transparent plastic optical lens for the LED down light with the narrow angular light distribution requirement in the LED lighting applications. In order to successfully complete the mission, the precise mid-field angular distribution model of the LED light source was established and built. And also the optical scattering surface property of the Harvey BSDF scattering model was designed, measured, and established. Then, the optical simulation for the entire optical system was performed to develop and design this solid transparent plastic optical lens system. Finally, the goals of 40 deg angular light distribution pattern defined at full width half maximum with glare reduced in the areas of interest and the optical performance of nearly 82% light energy transmission optics were achieved for the LED down light illumination.

  6. Scattering Optical Elements: Stand-Alone Optical Elements Exploiting Multiple Light Scattering.

    PubMed

    Park, Jongchan; Cho, Joong-Yeon; Park, Chunghyun; Lee, KyeoReh; Lee, Heon; Cho, Yong-Hoon; Park, YongKeun

    2016-07-26

    Optical design and fabrication techniques are crucial for making optical elements. From conventional lenses to diffractive optical elements and to recent metasurfaces, various types of optical elements have been proposed to manipulate light where optical materials are fabricated into desired structures. Here, we propose a scattering optical element (SOE) that exploits multiple light scattering and wavefront shaping. Instead of fabricating optical materials, the SOE consists of a disordered medium and a photopolymer-based wavefront recorder, with shapes impinging on light on demand. With the proposed stand-alone SOEs, we experimentally demonstrate control of various properties of light, including intensity, polarization, spectral frequency, and near field. Due to the tremendous freedom brought about by disordered media, the proposed approach will provide unexplored routes to manipulate arbitrary optical fields in stand-alone optical elements. PMID:27331616

  7. Shape-dependent light scattering properties of subwavelength silicon nanoblocks.

    PubMed

    Ee, Ho-Seok; Kang, Ju-Hyung; Brongersma, Mark L; Seo, Min-Kyo

    2015-03-11

    We explore the shape-dependent light scattering properties of silicon (Si) nanoblocks and their physical origin. These high-refractive-index nanostructures are easily fabricated using planar fabrication technologies and support strong, leaky-mode resonances that enable light manipulation beyond the optical diffraction limit. Dark-field microscopy and a numerical modal analysis show that the nanoblocks can be viewed as truncated Si waveguides, and the waveguide dispersion strongly controls the resonant properties. This explains why the lowest-order transverse magnetic (TM01) mode resonance can be widely tuned over the entire visible wavelength range depending on the nanoblock length, whereas the wavelength-scale TM11 mode resonance does not change greatly. For sufficiently short lengths, the TM01 and TM11 modes can be made to spectrally overlap, and a substantial scattering efficiency, which is defined as the ratio of the scattering cross section to the physical cross section of the nanoblock, of ∼9.95, approaching the theoretical lowest-order single-channel scattering limit, is achievable. Control over the subwavelength-scale leaky-mode resonance allows Si nanoblocks to generate vivid structural color, manipulate forward and backward scattering, and act as excellent photonic artificial atoms for metasurfaces. PMID:25668601

  8. IQENS - dynamic light scattering complementarity on hydrogenous systems

    NASA Astrophysics Data System (ADS)

    Magazu', S.

    1996-02-01

    This paper deals with two comparative studies of dynamic light scattering and incoherent quasi-elastic neutron scattering (IQENS) on hydrogenous systems, namely polymeric aqueous solutions and alcohols. In the first topic, attention is focused on the peculiar hydration processes present in poly(ethylene oxide) aqueous solutions and their influence on translational diffusive properties. Dynamic light scattering shows that water behaves as a good solvent and furnishes the temperature evolution of the hydration number. IQENS, on the other hand, reveals the presence of entangled water and evidences the effects of H-bond on the diffusive motions. The second topic concerns the study of rotational diffusion in two isomeric alcohols, normal-pentanol and 2-methyl-2-butanol. The comparison of the rotational relaxation times, obtained by IQENS and light scattering, allows to separate the self particle contribution from the collective one. The results allow, following Angell's classification, to attribute a more fragile character to the tertiary isomer and a stronger one to the primary alcohol.

  9. Dynamic Light Scattering Study of Pig Vitreous Body

    NASA Astrophysics Data System (ADS)

    Matsuura, Toyoaki; Idota, Naokazu; Hara, Yoshiaki; Annaka, Masahiko

    The phase behaviors and dynamical properties of pig vitreous body were studied by macroscopic observation of swelling behavior and dynamic light scattering under various conditions. From the observations of the dynamics of light scattered by the pig vitreous body under physiological condition, intensity autocorrelation functions that revealed two diffusion coefficients, D fast and D slow were obtained. We developed the theory for describing the density fluctuation of the entities in the vitreous gel system with sodium hyaluronate filled in the meshes of collagen fiber network. The dynamics of collagen and sodium hyaluronate explains two relaxation modes of the fluctuation. The diffusion coefficient of collagen obtained from D fast and D slow is very close to that in aqueous solution, which suggests the vitreous body is in the swollen state. Divergent behavior in the measured total scattered light intensities and diffusion coefficients upon varying the concentration of salt (NaCl and CaCl2) was observed. Namely, a slowing down of the dynamic modes accompanied by increased “static” scattered intensities was observed. This is indicative of the occurrence of a phase transition upon salt concentration.

  10. The Scattering of Light III. External Scattering from a Finite Molecular Fluid

    NASA Astrophysics Data System (ADS)

    Hynne, F.; Bullough, R. K.

    1990-03-01

    We calculate the external incoherent scattering from a finite molecular fluid exposed to a weak, external, coherent electromagnetic field. The scattered field is detected outside the fluid and the system models a real scattering experiment in all its aspects. The analysis is based on a classical all order many-body theory developed in two previous papers. The theory is microscopic, i.e. is developed ab initio and in detail in terms of individual scattering processes in vacuo at a strictly molecular level. But it is shown that the collective action of these generates all of the macroscopic features expected in the external scattering: for example, the refractive index, as it was calculated previously from the many-body theory, plays much of its expected macroscopic role. These macroscopic results are reached by showing that the complete scattering process (from a wave incident in vacuo on the fluid to a wave in vacuo scattered from the fluid) separates into three independent collective processes compactly described by a particular quadrilinear form quadratic in a field E induced in the fluid by any coherent external field, and quadratic in a `weight' field ɛ describing the scattered field in the fluid. The internal fields E and ɛ couple separately to the external incoming field and to one representing the external scattered field respectively. In each case they account for all collective surface effects. The kernel of the quadrilinear form accounts for all of the internal scattering processes in the fluid. The weight field ɛ and the equations associated with it describe refraction and (multiple) internal reflection of the scattered light at the surface of the medium in all details: these collective surface effects are managed in a very effective way through a new reciprocity principle derived from the microscopic theory and containing a new form of optical extinction theorem for external scattering. The kernel of the quadrilinear form for internal scattering has

  11. Light Scattering by Fractal Dust Aggregates. I. Angular Dependence of Scattering

    NASA Astrophysics Data System (ADS)

    Tazaki, Ryo; Tanaka, Hidekazu; Okuzumi, Satoshi; Kataoka, Akimasa; Nomura, Hideko

    2016-06-01

    In protoplanetary disks, micron-sized dust grains coagulate to form highly porous dust aggregates. Because the optical properties of these aggregates are not completely understood, it is important to investigate how porous dust aggregates scatter light. In this study, the light scattering properties of porous dust aggregates were calculated using a rigorous method, the T-matrix method, and the results were then compared with those obtained using the Rayleigh–Gans–Debye (RGD) theory and Mie theory with the effective medium approximation (EMT). The RGD theory is applicable to moderately large aggregates made of nearly transparent monomers. This study considered two types of porous dust aggregates—ballistic cluster–cluster agglomerates (BCCAs) and ballistic particle–cluster agglomerates. First, the angular dependence of the scattered intensity was shown to reflect the hierarchical structure of dust aggregates; the large-scale structure of the aggregates is responsible for the intensity at small scattering angles, and their small-scale structure determines the intensity at large scattering angles. Second, it was determined that the EMT underestimates the backward scattering intensity by multiple orders of magnitude, especially in BCCAs, because the EMT averages the structure within the size of the aggregates. It was concluded that the RGD theory is a very useful method for calculating the optical properties of BCCAs.

  12. Absorption and elastic scattering of light by particle aggregates.

    PubMed

    Quinten, M; Kreibig, U

    1993-10-20

    Light scattering and absorption by spherical particles is extended to aggregates of spheres with arbitrary shape and size. We applied the theory of G6rardy and Ausloos [Phys. Rev. B 25, 4204-4229 (1082)] to compute the total extinction loss spectra of several aggregates of nanometer-sized silver spheres from the near IR to the near UV. Silver was best suited to provide quantitative comparison with experiments concerning the scattering and absorption in the visible spectral region. Additional resonant extinction was obtained besides the resonant extinction of the single silver sphere. The spectra were discussed in detail to give general results that are independent of the particle material. PMID:20856447

  13. Cooperative scattering of light and atoms in ultracold atomic gases

    NASA Astrophysics Data System (ADS)

    Uys, H.; Meystre, P.

    2008-07-01

    Superradiance and coherent atomic recoil lasing are two closely related phenomena, both resulting from the cooperative scattering of light by atoms. In ultracold atomic gases below the critical temperature for Bose-Einstein condensation these processes take place with the simultaneous amplification of the atomic matter waves. We explore these phenomena by surveying some of the experimental and theoretical developments that have emerged in this field of study since the first observation of superradiant scattering from a Bose-Einstein condensate in 1999 [1].

  14. Halos and rainbows: The elastic scattering of light exotic nuclei

    SciTech Connect

    Satchler, G.R.; Hussein, M.H.

    1993-10-01

    The scattering of an exotic light nucleus with a halo is compared with that of a normal nucleus. Four, sometimes opposing effects arising from the halo are identified. Semiclassical expressions are derived which embody these effects. The cases of {sup 11}Li and {sup 11}C scattering from {sup 12}C at E/A = 60 MeV are compared. We conclude that the {sup 11}Li differential cross sections are probably smaller than those for {sup 11}C, in agreement with recent analyses of the measurements.

  15. Debye series for light scattering by a coated nonspherical particle

    SciTech Connect

    Xu Feng; Lock, James A.

    2010-06-15

    By using the extended boundary condition method, the Debye series is developed for light scattered by a coated nonspherical particle in order to interpret the angular dependence of the scattered intensity in terms of various physical processes. Numerical calculations are performed to study the influence of the coating thickness and the ellipticity of a coated spheroid on the angular position of the {alpha} and {beta} primary rainbows, which are produced by partial waves experiencing one internal reflection. The hyperbolic umbilic focal section is demonstrated and is analyzed for both the {alpha} and the {beta} rainbows.

  16. Debye series for light scattering by a coated nonspherical particle

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Lock, James A.

    2010-06-01

    By using the extended boundary condition method, the Debye series is developed for light scattered by a coated nonspherical particle in order to interpret the angular dependence of the scattered intensity in terms of various physical processes. Numerical calculations are performed to study the influence of the coating thickness and the ellipticity of a coated spheroid on the angular position of the α and β primary rainbows, which are produced by partial waves experiencing one internal reflection. The hyperbolic umbilic focal section is demonstrated and is analyzed for both the α and the β rainbows.

  17. Characterization of super smooth surfaces by light scattering techniques

    NASA Astrophysics Data System (ADS)

    Mattsson, Lars H.

    1989-03-01

    A characteristic feature of a supersmooth surface is its low scatter. The scatter is proportional to the square of the rms surface roughness. Therefore, light scattering is a suitable and nondestructive method for characterization of smooth surfaces. It is possible to detect scattering created by height differences of a few atomic layers but the lateral sensitivity is limited to the order of the wavelength, ~0.5μm. The new F 1048-87 ASTM standard test method for measuring the effective surface roughness of optical components is based on total integrated scattering (TIS). The amount of scattering, caused by the surface roughness, is of primary interest for optical applications, while the roughness itself is of greater concern in the fields of microelectronics and magnetic memory storage. This paper will highlight the use of a low noise TIS instrument for characterization of sub-Å roughness on semiconductor wafers, for thin film characterization, and for detection of traces of contamination on silicon surfaces.

  18. Stimulated Rayleigh-Brillouin gain spectroscopy in pure gases

    NASA Technical Reports Server (NTRS)

    She, C. Y.; Herring, G. C.; Moosmuller, H.; Lee, S. A.

    1983-01-01

    Stimulated Rayleigh-Brillouin gain spectra of pure gases are reported. Stimulated Rayleigh scattering is now clearly distinguishable from stimulated Brillouin scattering without the aid of induced absorption. As examples, spectral line shapes of Ar and SF6 at various pressures and the associated gain asymmetry are discussed. Potential applications of coherent Rayleigh-Brillouin spectroscopy are suggested.

  19. Orientation-Preserving Transfer and Directional Light Scattering from Individual Light-Bending Nanoparticles

    SciTech Connect

    Zhang, Yu; Barhoumi, Aoune; Lassiter, J. Britt; Halas, Naomi J.

    2011-04-13

    A nanocup, or semishell, is an asymmetric plasmonic “Janus” nanoparticle with electric and magnetic plasmon modes; the latter scatters light in a direction controlled by nanoparticle orientation, making it the nanoscale analog of a parabolic antenna. Here we report a method for transferring nanocups from their growth substrate to oxide-terminated substrates that precisely preserves their three-dimensional orientation, enabling their use as nanophotonic components. This enables us to selectively excite and probe the electric and magnetic plasmon modes of individual nanocups, showing how the scattered light depends on the direction of incoming light and the orientation of this nanoparticle antenna.

  20. Efficient light scattering in plasmonic light trapping designs for thin film solar cells

    NASA Astrophysics Data System (ADS)

    Ji, Liming; Varadan, Vasundara V.

    2015-04-01

    Plasmonic structures have been proposed for enhancing light absorption in thin film solar cells, for which insufficient light absorption is a limiting factor for further improvement of efficiency. The optical path of light in the absorber layer of a solar cell is increased due to the enhanced light scattering by plasmonic structures at resonance. This process involves two steps of energy conversion: light-electron and then electron-light. The first step couples optical energy into the kinetic energy of collective electron motions in plasmonic structures, forming oscillating current. This step is easy to implement as long as plasmonic structures are at resonance. The second step releases the energy from electrons to photons. An efficient release of photon energy is a must for solar cell applications and it is dependent on the two competing effects: light scattering and field localization that results in heat loss. Theoretical discussions and simulation work are provided in the paper. The scattering of light by a plasmonic structure is analyzed based on the antenna radiation theory. Three factors are found to be important for the efficiency of a plasmonic light trapping design: the radiation of each unit structure, the array factor and the energy feeding of the structure. An efficient plasmonic light trapping design requires proper considerations of all the three factors.

  1. In situ measurement of inelastic light scattering in natural waters

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin

    Variation in the shape of solar absorption (Fraunhofer) lines are used to study the inelastic scattering in natural waters. In addition, oxygen absorption lines near 689nm are used to study the solar stimulated chlorophyll fluorescence. The prototype Oceanic Fraunhofer Line Discriminator (OFLD) has been further developed and improved by using a well protected fiber optic - wire conductor cable and underwater electronic housing. A Monte-Carlo code and a simple code have been modified to simulate the Raman scattering, DOM fluorescence and chlorophyll fluorescence. A series of in situ measurements have been conducted in clear ocean waters in the Florida Straits, in the turbid waters of Florida Bay, and in the vicinity of a coral reef in the Dry Tortugas. By comparing the reduced data with the model simulation results, the Raman scattering coefficient, b r with an excitation wavelength at 488nm, has been verified to be 2.6 × 10-4m-1 (Marshall and Smith, 1990), as opposed to 14.4 × 10- 4m-1 (Slusher and Derr, 1975). The wavelength dependence of b r cannot be accurately determined from the data set as the reported values (λ m-4 to λ m- 5) have an insignificant effect in the natural underwater light field. Generally, in clear water, the percentage of inelastic scattered light in the total light field at /lambda < 510nm is negligible for the whole water column, and this percentage increases with depth at /lambda > 510nm. At low concentrations (a y(/lambda = 380nm) less than 0.1m-1), DOM fluorescence plays a small role in the inelastic light field. However, chlorophyll fluorescence is much stronger than Raman scattering at 685nm. In shallow waters where a sea bottom affects the ambient light field, inelastic light is negligible for the whole visible band. Since Raman scattering is now well characterized, the new OFLD can be used to measure the solar stimulated in situ fluorescence. As a result, the fluorescence signals of various bottom surfaces, from coral to

  2. Long-wavelength scattered-light halos in ASC CCDs

    NASA Astrophysics Data System (ADS)

    Sirianni, Marco; Clampin, Mark; Hartig, George F.; Rafal, Marc D.; Ford, Holland C.; Golimowski, David A.; Tremonti, C.; Illingworth, Garth; Blouke, Morley M.; Lesser, Michael P.; Burmester, William; Kimble, Randy A.; Sullivan, Pamela; Krebs, Carolyn A.; Yagelowicz, John

    1998-07-01

    During the ground calibration of the Space Telescope Imaging Spectrograph (STIS) large scattered light haloes were identified in images of point sources and long slit spectral images at long wavelengths (greater than 750 nm). The long wavelength scattering was traced to the SITe 1024 X 1024 CCD and its header package, raising concerns for the performance of the Advanced Camera for Surveys (ACS) CCD detectors. ACS is a third generation axial instrument for the Hubble Space Telescope (HST) and will be installed during the 1999 Servicing Mission. Two of the ACS imaging channels employ SITe CCDs, so the ACS team have conducted a study of the long- wavelength scattering, in collaboration with SITe, to assess the impact to the ACS science program and develop a solution. In this paper we discuss our solution, its implementation on ACS CCDs, and describe the results of initial tests.

  3. Paper area density measurement from forward transmitted scattered light

    DOEpatents

    Koo, Jackson C.

    2001-01-01

    A method whereby the average paper fiber area density (weight per unit area) can be directly calculated from the intensity of transmitted, scattered light at two different wavelengths, one being a non-absorpted wavelength. Also, the method makes it possible to derive the water percentage per fiber area density from a two-wavelength measurement. In the optical measuring technique optical transmitted intensity, for example, at 2.1 microns cellulose absorption line is measured and compared with another scattered, optical transmitted intensity reference in the nearby spectrum region, such as 1.68 microns, where there is no absorption. From the ratio of these two intensities, one can calculate the scattering absorption coefficient at 2.1 microns. This absorption coefficient at this wavelength is, then, experimentally correlated to the paper fiber area density. The water percentage per fiber area density can be derived from this two-wavelength measurement approach.

  4. Angularly-resolved elastic light scattering of micro-particles

    NASA Astrophysics Data System (ADS)

    Aptowicz, Kevin B.

    From microbiology to astrophysics, the scientific community has long embraced elastic light scattering from small particles as a diagnostic tool. Elastic light scattering has an extremely large scattering cross-section, allowing for single particle interrogation. This is critical in applications where trace amounts of suspect particles are to be detected in a diverse background of natural aerosols. By angularly-resolving the elastically scattered light, features can be detected in these patterns that are sensitive to a particle's morphology (shape, size, internal structure, and composition). An apparatus to collect LA TAOS (Large-Angle Two-dimensional Angular Optical Scattering) patterns from single particles in-situ and in real-time was designed and constructed. The setup utilizes a cross-beam trigger system to minimize the effects of the aberration coma stemming from the main collection optic, an ellipsoidal mirror. LA TAOS patterns of ambient aerosols were collected and analyzed. Approximately 15% of the ambient aerosol had a sphere-like shape. The refractive index of these spheres was estimated by curve-fitting to Lorenz-Mie theory. In addition, the island features prevalent in the LA TAOS pattern were analyzed. Metrics generated from these were used to get partial discrimination between clusters of Bacillus subtilis spores (a simulant for anthrax) and aerosol particles found in the ambient atmosphere. A novel experimental setup for collecting simultaneously LA TAOS patterns at two wavelengths in the mid-infrared was also implemented. With this setup, the relative strength of single-particle absorption could be discerned at the two illuminating wavelengths.

  5. Interactions in Undersaturated and Supersaturated Lysozyme Solutions: Static and Dynamic Light Scattering Results

    NASA Technical Reports Server (NTRS)

    Muschol, Martin; Rosenberger, Franz

    1995-01-01

    We have performed multiangle static and dynamic light scattering studies of lysozyme solutions at pH=4.7. The Rayleigh ratio R(sub g) and the collective diffusion coefficient D(sub c) were determined as function of both protein concentration c(sub p) and salt concentration c(sub s) with two different salts. At low salt concentrations, the scattering ratio K(sub c)(sub p)/R(sub theta) and diffusivity increased with protein concentration above the values for a monomeric, ideal solution. With increasing salt concentration this trend was eventually reversed. The hydrodynamic interactions of lysozyme in solution, extracted from the combination of static and dynamic scattering data, decreased significantly with increasing salt concentration. These observations reflect changes in protein interactions, in response to increased salt screening, from net repulsion to net attraction. Both salts had the same qualitative effect, but the quantitative behavior did not scale with the ionic strength of the solution. This indicates the presence of salt specific effects. At low protein concentrations, the slopes of K(sub c)(sub p)/R(sub theta) and D(sub c) vs c(sub p) were obtained. The dependence of the slopes on ionic strength was modeled using a DLVO potential for colloidal interactions of two spheres, with the net protein charge Z(sub e) and Hamaker constant A(sub H) as fitting parameters. The model reproduces the observed variations with ionic strength quite well. Independent fits to the static and dynamic data, however, led to different values of the fitting parameters. These and other shortcomings suggest that colloidal interaction models alone are insufficient to explain protein interactions in solutions.

  6. Ultrasensitive and Highly Selective Detection Of Alzheimer’s Disease Biomarker Using Two-Photon Rayleigh Scattering Properties of Gold Nanoparticle

    PubMed Central

    Neely, Adria; Perry, Candice; Varisli, Birsen; Singh, Anant K.; Arbneshi, Tahir; Senapati, Dulal; Kalluri, Jhansi Rani

    2009-01-01

    Alzheimer’s disease (AD) is a progressive mental disorder disease, which affects 26.6 million people in worldwide and estimated increments can be 100 millions by 2050. Since there is no cure at present, early diagnosis of AD is crucial for the current drugs treatments. Driven by the need, here we demonstrate for the first time that monoclonal ani-tau antibody coated gold nanoparticle based two-photon scattering assay can be used for the detection of Alzheimer’s tau protein in 1 pg/mL level which is about two orders of magnitude lower than cut-off values (195 pg/mL) for tau protein in CSF (cerebrospinal fluid). We have shown that when ani-tau antibody coated gold nanoparticle were mixed with 20 ng/ml of tau protein, two-photon Rayleigh scattering intensity (TPRS) increases by about 16 times. The mechanism of TPRS intensity change has been discussed. Our data demonstrated that our TPRS assay is highly sensitive to Tau protein and it can distinguish from BSA, which is one of the most abundant protein components in CSF. Our results demonstrate the potential for a broad application of this type of nano-bionanotechnology in practical biomedical applications. PMID:19691350

  7. A Possible Application of Coherent Light Scattering on Biological Fluids

    NASA Astrophysics Data System (ADS)

    Chicea, Dan; Chicea, Liana Maria

    2007-04-01

    Human urine from both healthy patients and patients with different diseases was used as scattering medium in a coherent light scattering experiment. The time variation of the light intensity in the far field speckle image was acquired using a data acquisition system on a PC and a time series resulted for each sample. The autocorrelation function for each sample was calculated and the autocorrelation time was determined. The same samples were analyzed in a medical laboratory using the standard procedure. We found so far that the autocorrelation time is differently modified by the presence of pus, albumin, urobilin and sediments. The results suggest a fast procedure that can be used as laboratory test to detect the presence not of each individual component in suspensions but of big conglomerates as albumin, cylinders, oxalate crystals.

  8. Space telescope low scattered light camera - A model

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Kuper, T. G.; Shack, R. V.

    1982-01-01

    A design approach for a camera to be used with the space telescope is given. Camera optics relay the system pupil onto an annular Gaussian ring apodizing mask to control scattered light. One and two dimensional models of ripple on the primary mirror were calculated. Scattered light calculations using ripple amplitudes between wavelength/20 wavelength/200 with spatial correlations of the ripple across the primary mirror between 0.2 and 2.0 centimeters indicate that the detection of an object a billion times fainter than a bright source in the field is possible. Detection of a Jovian type planet in orbit about alpha Centauri with a camera on the space telescope may be possible.

  9. Comprehensive nanostructure and defect analysis using a simple 3D light-scatter sensor.

    PubMed

    Herffurth, Tobias; Schröder, Sven; Trost, Marcus; Duparré, Angela; Tünnermann, Andreas

    2013-05-10

    Light scattering measurement and analysis is a powerful tool for the characterization of optical and nonoptical surfaces. A new 3D scatter measurement system based on a detector matrix is presented. A compact light-scatter sensor is used to characterize the scattering and nanostructures of surfaces and to identify the origins of anisotropic scattering features. The results from the scatter sensor are directly compared with white light interferometry to analyze surface defects as well as surface roughness and the corresponding scattering distributions. The scattering of surface defects is modeled based on the Kirchhoff integral equation and the approach of Beckmann for rough surfaces. PMID:23669841

  10. SCATTERED NEBULAR LIGHT IN THE EXTENDED ORION NEBULA

    SciTech Connect

    O'Dell, C. R.; Goss, W. M.

    2009-11-15

    We have combined 327.5 MHz radio observations and optical spectroscopy to study conditions in the Extended Orion Nebula (EON). We see a steady progression of characteristics with increasing distance from the dominant photoionizing star {theta}{sup 1}Ori C. This progression includes a decrease in the F(H{alpha})/F(H{beta}) ratio, an increase in the relative strength of scattered stellar continuum, decrease in electron density determined from the [S II] doublet, and increase in the ratio of emission measures derived from the H{beta} line and the 327.5 MHz radio continuum. We conclude that beyond about 5' south of {theta}{sup 1}Ori C that scattered light from the much brighter central Huygens region of the nebula significantly contaminates local emission. This strengthens earlier arguments that wavelength and model-dependent scattering of emission-line radiation imposes a fundamental limit on our ability to determine the physical conditions and abundances in this and arguably other similar Galactic Nebulae. The implications for the study of extragalactic H II regions are even more severe. We confirm the result of an earlier study that at least the eastern boundary of the EON is dominated by scattered light from the Huygens region.

  11. Light pulse propagation and charge carrier scattering in semiconductor amplifiers

    SciTech Connect

    Binder, R.; Knorr, A.; Koch, S.W.

    1994-12-31

    The carrier dynamics in inverted semiconductors (optical amplifiers) and light pulse propagations in optical amplifiers have been studied extensively both theoretically and experimentally. Light induced carrier heating processes, which are caused, for example, by two-photon absorption and free carrier absorption, have been studied mainly on the basis of phenomenological models. The full microscopic theory of these processes and their influence on light pulse propagation is still an unsolved problem. Here, the authors present theoretical results on light pulse propagation in inverted semiconductors and semiconductor laser diodes. The theory is based on the semiconductor Maxwell Bloch equations and includes incoherent phenomena due to charge-carrier scattering based on the solution of the appropriate Boltzman equation.

  12. Metamaterials. Invisibility cloaking in a diffusive light scattering medium.

    PubMed

    Schittny, Robert; Kadic, Muamer; Bückmann, Tiemo; Wegener, Martin

    2014-07-25

    In vacuum, air, and other surroundings that support ballistic light propagation according to Maxwell's equations, invisibility cloaks that are macroscopic, three-dimensional, broadband, passive, and that work for all directions and polarizations of light are not consistent with the laws of physics. We show that the situation is different for surroundings leading to multiple light scattering, according to Fick's diffusion equation. We have fabricated cylindrical and spherical invisibility cloaks made of thin shells of polydimethylsiloxane doped with melamine-resin microparticles. The shells surround a diffusively reflecting hollow core, in which arbitrary objects can be hidden. We find good cloaking performance in a water-based diffusive surrounding throughout the entire visible spectrum and for all illumination conditions and incident polarizations of light. PMID:24903561

  13. Light source for narrow and broadband coherent Raman scattering microspectroscopy.

    PubMed

    Brinkmann, Maximilian; Dobner, Sven; Fallnich, Carsten

    2015-12-01

    We present a light source that is well adapted to both narrow- and broadband coherent Raman scattering (CRS) methods. Based on a single oscillator, the light source delivers synchronized broadband pulses via supercontinuum generation and narrowband, frequency-tunable pulses via four-wave mixing in a photonic crystal fiber. Seeding the four-wave mixing with a spectrally filtered part of the supercontinuum yields high-pulse energies up to 8 nJ and the possibility of scanning a bandwidth of 2000  cm(-1) in 25 ms. All pulses are emitted with a repetition frequency of 1 MHz, which ensures efficient generation of CRS signals while avoiding significant damage of the samples. Consequently, the light source combines the performance of individual narrow- and broadband CRS light sources in one setup, thus enabling hyperspectral imaging and rapid single-resonance imaging in parallel. PMID:26625022

  14. Quasielastic Light Scattering Measurements of the Anisotropic Mechanical Properties of a Polymer Nematic Liquid Crystal.

    NASA Astrophysics Data System (ADS)

    Taratuta, Victor Gregory

    An experimental investigation of macroscopic mechanical properties of a polymer nematic liquid crystal was conducted on nematic solutions formed from rigid or semiflexible main chain polymers that are fully extended in a solution. The particular system under investigation is a poly-(gamma) -benzyl glutamate (PBG) which belongs to a class of synthetic polypeptides. Quasielastic Rayleigh light scattering on well aligned nematic single crystals of PBG was used to measure the elastic constants and the anisotropic viscosities as a function of concentration. The elastic constants are measured from the intensity of the scattered light which is determined by the amplitude of thermally excited director fluctuations. That amplitude depends on the energy of the fluctuation which is proportional to the appropriate elastic constant. The viscosities associated with the elastic deformation modes are computed from the characteristic relaxation times of the fluctuations by measuring their temporal autocorrelation function. The splay and bend elastic constants were found to be very similar in magnitude; both showed a linear dependence on concentration. The twist elastic constant was much smaller than either splay or bend and showed only a weak concentration dependence. Four out of five independent Leslie viscosities were measured (except the elongational flow viscosity (alpha)(,1)). The viscosities were found to exhibit very large anisotropies. Different types of viscosities showed distinctly different patterns of concentration dependence. (gamma)(,1) and (eta)(,c) were quadratic in concentration, (eta)(,a) was linear in concentration, and (eta)(,b) did not show any strong concentration dependence. The viscosity data indicate that even at a moderate length to diameter ratio studied (L/D - 30), the PBG approaches a behavior predicted for a system composed of infinitely long molecular chains. The concentration dependence data for the elastic constants and the anisotropic viscosities

  15. Development of a versatile laser light scattering instrument

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Ansari, Rafat R.

    1992-01-01

    NASA Lewis Research Center is providing and coordinating the technology for placing a compact Laser Light Scattering (LLS) instrument in a microgravity environment. This will be accomplished by defining and assessing user requirements for microgravity experiments, coordinating needed technological developments, and filling technical gaps. This effort is striving to brassboard and evaluate a miniature multi-angle LLS instrument. The progress of the program is reported.

  16. Light scattering measurements supporting helical structures for chromatin in solution.

    PubMed

    Campbell, A M; Cotter, R I; Pardon, J F

    1978-05-01

    Laser light scattering measurements have been made on a series of polynucleosomes containing from 50 to 150 nucleosomes. Radii of gyration have been determined as a function of polynucleosome length for different ionic strength solutions. The results suggest that at low ionic strength the chromatin adopts a loosely helical structure rather than a random coil. The helix becomes more regular on increasing the ionic strength, the dimension resembling those proposed by Finch and Klug for their solenoid model. PMID:662693

  17. Using light scattering to evaluate the separation of polydisperse nanoparticles.

    PubMed

    Galyean, Anne A; Vreeland, Wyatt N; Filliben, James J; Holbrook, R David; Ripple, Dean C; Weinberg, Howard S

    2015-07-30

    The analysis of natural and otherwise complex samples is challenging and yields uncertainty about the accuracy and precision of measurements. Here we present a practical tool to assess relative accuracy among separation protocols for techniques using light scattering detection. Due to the highly non-linear relationship between particle size and the intensity of scattered light, a few large particles may obfuscate greater numbers of small particles. Therefore, insufficiently separated mixtures may result in an overestimate of the average measured particle size. Complete separation of complex samples is needed to mitigate this challenge. A separation protocol can be considered improved if the average measured size is smaller than a previous separation protocol. Further, the protocol resulting in the smallest average measured particle size yields the best separation among those explored. If the differential in average measured size between protocols is less than the measurement uncertainty, then the selected protocols are of equivalent precision. As a demonstration, this assessment metric is applied to optimization of cross flow (V(x)) protocols in asymmetric flow field flow fractionation (AF(4)) separation interfaced with online quasi-elastic light scattering (QELS) detection using mixtures of polystyrene beads spanning a large size range. Using this assessment metric, the V(x) parameter was modulated to improve separation until the average measured size of the mixture was in statistical agreement with the calculated average size of particles in the mixture. While we demonstrate this metric by improving AF(4) V(x) protocols, it can be applied to any given separation parameters for separation techniques that employ dynamic light scattering detectors. PMID:26320655

  18. Periodic or random nanostructures for light scattering control

    NASA Astrophysics Data System (ADS)

    Berginc, Gerard

    2016-04-01

    Our paper mainly focuses on the control of light scattering by periodic or randomly rough structures. First designed with bi-periodical structures, antireflective surfaces can be achieved with random patterns. We present some new structures with periodic or random patterns, which have been designed by rigorous numerical methods (FDTD) or analytical methods. We show that random interfaces offer new degrees of freedom and possibilities by control of their statistical properties.

  19. Elasticity of biomembranes studied by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Fujime, Satoru; Miyamoto, Shigeaki

    1991-05-01

    Combination of osmotic swelling and dynamic light scattering makes it possible to measure the elastic modulus of biomembranes. By this technique we have observed a drastic increase in membrane flexibility on activation of Na/glucose cotransporters in membrane vesicles prepared from brush-borders of rat small intestine and on activation by micromolar [Ca2] of exocytosis in secretory granules isolated from rat pancreatic acinar cells and bovine adrenal chromaffin cells. 1 .

  20. Light scattering studies of an electrorheological fluid in oscillatory shear

    SciTech Connect

    Martin, J.E.; Odinek, J.

    1995-12-31

    We have conducted a real time, two-dimensional light scattering study of the nonlinear dynamics of field-induced structures in an electrorheological fluid subjected to oscillatory shear. We have developed a kinetic chain model of the observed dynamics by considering the response of a fragmenting/aggregating particle chain to the prevailing hydrodynamic and electrostatic forces. This structural theory is then used to describe the nonlinear rheology of ER fluids.