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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. Hyper-Rayleigh light scattering from an aqueous suspension of purple membrane.

    PubMed

    Schmidt, P K; Rayfield, G W

    1994-07-01

    Here we report the first observation of hyper-Rayleigh light scattering from bacteriorhodopsin in the form of an aqueous suspension of unoriented purple membranes. A typical purple membrane suspension used in our experiments contains approximately 10(8) randomly oriented purple membranes. Each purple membrane contains approximately 10(5) bacteriorhodopsin molecules in a two-dimensional crystallinearray. Hyper-Rayleigh light scattering is observed when the purple membrane suspension is illuminated with light that has a wavelength of 1064 nm. We propose that the 532-nm scattered light from each of the bacteriorhodopsin molecules in a single purple membrane is coherent, and that the scattered light from different purple membranes is incoherent. This proposal is supported by the following experimental observations: (a) the 532-nm light intensity is proportional to the square of the incident power, (b) the intensity of the 532-nm signal is linearly proportional to the concentration of purple membrane in solution, (c) the scattered 532-nm light is incoherent, (d) the scattered 532-nm light intensity decreases if the size of the purple membranes is reduced while the bacteriorhodopsin concentration is kept constant, and (e) the 532-nm light is due to the retinal chromophore of the bacteriorhodopsin molecule. The ratio of horizontal polarized hyper-Rayleigh scattered light to vertically polarized hyper-Rayleigh scattered light gives the angle (23 ± 4°) of the retinal axis with respect to the plane of the purple membrane. The hyperpolarizability of the bacteriorhodopsin molecule is found to be 5 ± 0.4 × 10(-27) esu.

  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 Central

    Antoun, Ayman; Pavlov, Michael Y.; Tenson, Tanel

    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. Calculations of scattered light from rigid polymers by Shifrin and Rayleigh-Debye approximations.

    PubMed Central

    Bishop, M F

    1989-01-01

    We show that the commonly used Rayleigh-Debye method for calculating light scattering can lead to significant errors when used for describing scattering from dilute solutions of long rigid polymers, errors that can be overcome by use of the easily applied Shifrin approximation. In order to show the extent of the discrepancies between the two methods, we have performed calculations at normal incidence both for polarized and unpolarized incident light with the scattering intensity determined as a function of polarization angle and of scattering angle, assuming that the incident light is in a spectral region where the absorption of hemoglobin is small. When the Shifrin method is used, the calculated intensities using either polarized or unpolarized scattered light give information about the alignment of polymers, a feature that is lost in the Rayleigh-Debye approximation because the effect of the asymmetric shape of the scatterer on the incoming polarized electric field is ignored. Using sickle hemoglobin polymers as an example, we have calculated the intensity of light scattering using both approaches and found that, for totally aligned polymers within parallel planes, the difference can be as large as 25%, when the incident electric field is perpendicular to the polymers, for near forward or near backward scattering (0 degrees or 180 degrees scattering angle), but becomes zero as the scattering angle approaches 90 degrees. For randomly oriented polymers within a plane, or for incident unpolarized light for either totally oriented or randomly oriented polymers, the difference between the two results for near forward or near backward scattering is approximately 15%. PMID:2605302

  7. Rayleigh light scattering properties of atmospheric molecular clusters consisting of sulfuric acid and bases.

    PubMed

    Elm, Jonas; Norman, Patrick; Mikkelsen, Kurt V

    2015-06-28

    The Rayleigh light scattering properties of (H2SO4)a(NH3)b and (H2SO4)a((CH3)2NH)b atmospheric molecular clusters have been investigated using a response theory approach. Using density functional theory the molecular structures and stepwise formation free energies of clusters with a and b up to 4 have been re-investigated. The Rayleigh scattering intensities are calculated from the dipole polarizability tensor α using the CAM-B3LYP functional by applying linear response methods. The intrinsic scattering properties of (H2SO4)a(NH3)b and (H2SO4)a((CH3)2NH)b indicate that amine containing clusters scatter light significantly more efficiently then their ammonia containing counterparts. Using the Atmospheric Cluster Dynamics Code (ACDC) the steady state cluster concentrations are estimated and the effective scattering is calculated. The effective scattering is shown to be highly dependent on the estimated concentrations and indicates that there exist competitive pathways, such as nucleation and coagulation, which influence the cluster distributions. The frequency dependence of the scattering is found to depend on the cluster composition and show increased responses when clusters contain more bases than acid molecules. Based on structures obtained using semi-empirical molecular dynamics simulations the Rayleigh scattering properties of clusters with up to 20 acid-base pairs are evaluated. This study represents the first step towards gaining a fundamental understanding of the scattering properties of small atmospheric clusters in the ambient atmosphere.

  8. 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.

  9. 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.

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

    PubMed Central

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

    2014-01-01

    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. PMID:25227918

  11. [Determination of protein concentration by the enhancement of Rayleigh light scattering of fuchsine acid].

    PubMed

    Zhang, Hong-yi; Liu, Bao-sheng; Zhang, Hong-lei; Zhao, Yong

    2002-12-01

    A new Rayleigh light scattering (RLS) assay is presented in this paper. At the optimum pH = 2.72, the weak RLS of fuchsine acid can be greatly enhanced by the addition of proteins due to the interaction between protein and fuchsine acid. A new quantitative determination method for proteins has been developed. The linear range for human serum albumin is 0-4.0 mg.L-1 with detection limit of 23 micrograms.L-1. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability and few interfering substances. The determination results of the proteins in human serum and urine samples are very close those obtained using Biuret method, with relative stand deviation of 0.94%-4.93%.

  12. Linking Rayleigh-Rice theory with near linear shift invariance in light scattering phenomena

    NASA Astrophysics Data System (ADS)

    Stover, John C.; Schroeder, Sven; Staats, Chris; Lopushenko, Vladimir; Church, Eugene

    2016-09-01

    Understanding topographic scatter has been the subject of many publications. For optically smooth surfaces that scatter only from roughness (and not from contamination, films or bulk defects) the Rayleigh-Rice relationship resulting from a rigorous electromagnetic treatment has been successfully used for over three decades and experimentally proven at wavelengths ranging from the X-Ray to the far infrared (even to radar waves). The "holy grail" of roughness-induced scatter would be a relationship that is not limited to just optically smooth surfaces, but could be used for any surface where the material optical constants and the surface power spectral density function (PSD) are known. Just input these quantities and calculate the BRDF associated with any source incident angle, wavelength and polarization. This is an extremely challenging problem, but that has not stopped a number of attempts. An intuitive requirement on such general relationships is that they must reduce to the simple Rayleigh-Rice formula for sufficiently smooth surfaces. Unfortunately that does not always happen. Because most optically smooth surfaces also scatter from non-topographic features, doubt creeps in about the accuracy of Rayleigh-Rice. This paper investigates these issues and explains some of the confusion generated in recent years. The authors believe there are measurement issues, scatter source issues and rough surface derivation issues, but that Rayleigh- Rice is accurate as formulated and should not be "corrected." Moreover, it will be shown that the empirically observed near shift invariance of surface scatter phenomena is a direct consequence of the Rayleigh-Rice theory.

  13. Rayleigh scattering. [molecular scattering terminology redefined

    NASA Technical Reports Server (NTRS)

    Young, A. T.

    1981-01-01

    The physical phenomena of molecular scattering are examined with the objective of redefining the confusing terminology currently used. The following definitions are proposed: molecular scattering consists of Rayleigh and vibrational Raman scattering; the Rayleigh scattering consists of rotational Raman lines and the central Cabannes line; the Cabannes line is composed of the Brillouin doublet and the central Gross or Landau-Placzek line. The term 'Rayleigh line' should never be used.

  14. 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.

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

    PubMed

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

    2015-07-01

    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.

  18. 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.

  19. Rayleigh Scattering by Helium in Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Fišák, J.; Kubát, J.; Krtička, J.

    2017-02-01

    We study the influence of Rayleigh scattering by helium on synthetic spectra and stellar atmosphere models. Rayleigh scattering by helium is often neglected in hot star atmosphere models. This approximation is justified by the small population of helium in stars with solar composition (about 10% by number) and lower Rayleigh scattering total cross section of helium with respect to neutral hydrogen. However, for stars with large helium abundances Rayleigh scattering by helium can be a significant opacity source.

  20. Rayleigh, Raman and particulate scattering

    NASA Technical Reports Server (NTRS)

    Cochran, W. D.

    1982-01-01

    Analysis of the visible and near infrared spectra of planetary atmospheres and the multiple scattering of photons within the atmosphere are discussed. Photons detected within the spectral region are solar photons which were scattered by the gas and particles in the planetary atmosphere. An example is given for the incident and emitted fluxes for a hypothetical planet with an effective temperature of 100 K. The absorption spectrum of the planetary atmosphere is discussed in terms of the various scattering processes photons undergo within the atmosphere. Three different physical processes are considered. Rayleigh scattering and Raman scattering by the gas molecules, and scattering by any cloud or dust aerosol particles in the atmosphere. The physics of each of these processes is examined.

  1. Determination of proteins at nanogram levels based on their enhancement effects of Rayleigh light scattering on dibromomethylchlorophosphonazo

    NASA Astrophysics Data System (ADS)

    Li, Qianfeng; Zhang, Hongyi; Xue, Chunxia; Chen, Xingguo; Hu, Zhide

    2000-11-01

    A new Rayleigh light scattering (RLS) assay of protein was conducted in this paper. At the optimum pH conditions, and in the presence of Tween-20, the weak RLS of dibromomethylchlorophosphonazo (DBM-CPA) can be enhanced greatly by the addition of proteins. Based on this, the reactions of DBM-CPA and proteins were studied. A new quantitative determination method for proteins has been developed. The method is simple, practical and relatively free from interference from coexisting substances, as well as much more sensitive (the dynamic ranges of 0.065-40.05 μg ml -1 and detection limit of 30 ng ml -1 for bovine serum albumin (BSA)) than most of the existing assays. The determination results of human body serum samples are identical to those by the CBB method, with relative S.D. of six determination of 0.5-2.2%.

  2. 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…

  3. 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.

  4. 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.

  5. In situ Characterization of Nanoparticles Using Rayleigh Scattering

    PubMed Central

    Santra, Biswajit; Shneider, Mikhail N.; Car, Roberto

    2017-01-01

    We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols. PMID:28071715

  6. In situ Characterization of Nanoparticles Using Rayleigh Scattering.

    PubMed

    Santra, Biswajit; Shneider, Mikhail N; Car, Roberto

    2017-01-10

    We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols.

  7. In situ Characterization of Nanoparticles Using Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Santra, Biswajit; Shneider, Mikhail N.; Car, Roberto

    2017-01-01

    We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols.

  8. 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.

  9. Determination of nucleic acids with tetra-( N-hexadecylpyridiniumyl) porphyrin sensitized by cetyltrimethylammonium bromide (CTMAB) using a Rayleigh light-scattering technique

    NASA Astrophysics Data System (ADS)

    Zhu, Changqing; Zhuo, Shujuan; Li, Yongxin; Wang, Lun; Zhao, Danhua; Chen, Jinlong; Wu, Yuqin

    2004-03-01

    Using a common spectrofluorometer to measure the intensity of Rayleigh light-scattering (RLS), a method for determination of nucleic acids has been developed. At pH 10.24 and ionic strength 0.01 mol l -1 (NaCl), the Rayleigh light-scattering of the tetra-( N-hexadecylpyridiniumyl) porphyrin (TC 16PyP) is greatly enhanced by nucleic acids in the presence of cetyltrimethylammonium bromide (CTMAB), with the scattering peak located at 311.8 nm. The enhanced RLS intensity is in proportion to the concentration of calf thymus DNA (ctDNA) in the range 0.2-6.0 μg ml -1 and to that of fish sperm DNA (fsDNA) in the range 0.05-3.0 μg ml -1. The limits of detection are 0.016 μg ml -1 for calf thymus DNA and 0.023 μg ml -1 for fish sperm DNA when the concentration of TPP was chosen 2.0×10 -6 mol l -1. Four synthetic samples were determined satisfactorily.

  10. 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

  11. Stimulated thermal Rayleigh scattering in optical fibers.

    PubMed

    Dong, Liang

    2013-02-11

    Recently, mode instability was observed in optical fiber lasers at high powers, severely limiting power scaling for single-mode outputs. Some progress has been made towards understanding the underlying physics. A thorough understanding of the effect is critical for continued progress of this very important technology area. Mode instability in optical fibers is, in fact, a manifestation of stimulated thermal Rayleigh scattering. In this work, a quasi-closed-form solution for the nonlinear coupling coefficient is found for stimulated thermal Rayleigh scattering in optical fibers. The results help to significantly improve understanding of mode instability.

  12. 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.

  13. 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.

  14. 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.

  15. The analytical application and spectral investigation of DNA-CPB-emodin and sensitive determination of DNA by resonance Rayleigh light scattering technique

    NASA Astrophysics Data System (ADS)

    Bi, Shuyun; Wang, Yu; Wang, Tianjiao; Pang, Bo; Zhao, Tingting

    2013-01-01

    A new sensitive DNA probe containing cetylpyridinium bromide (CPB) and emodin (an effective component of Chinese herbal medicine) was developed using the resonance Rayleigh light scattering (RLS) technique. A novel assay was first developed to detect DNA at nanogram level based on the ternary system of DNA-CPB-emodin. The RLS signal of DNA was enhanced remarkably in the presence of emodin-CPB, and the enhanced RLS intensity at 340.0 nm was in direct proportion to DNA concentration in the range of 0.01-2.72 μg mL-1 with a good linear relationship. The detection limit was 1.5 ng mL-1. Three synthetic DNA samples were measured obtaining satisfactory results, the recovery was 97.6-107.3%.

  16. Rayleigh scattering in sapphire test mass for laser interferometric gravitational-wave detectors:. II: Rayleigh scattering induced noise in a laser interferometric-wave detector

    NASA Astrophysics Data System (ADS)

    Benabid, F.; Notcutt, M.; Ju, L.; Blair, D. G.

    1999-10-01

    We present the level of noise induced by Rayleigh-scattered light from sapphire test mass, the limit of scattering loss on build-up power inside the interferometer and finally the tolerable absorption loss in order to meet the specification of the interferometer sensitivity. The results show that the Rayleigh scattering induced noise remains below h˜10 -25 Hz -1/2 and a higher tolerance on the absorption level in sapphire substrate compared with silica substrate.

  17. Molecular filtered Rayleigh scattering applied to combustion

    NASA Astrophysics Data System (ADS)

    Elliott, Gregory S.; Glumac, Nick; Carter, Campbell D.

    2001-04-01

    Molecular filtered Rayleigh scattering (FRS), employing an iodine vapour filter and an injection-seeded Nd:YAG laser, was utilized to measure instantaneous and average temperature fields in combustion environments. With FRS thermometry, the vapour within the cell strongly absorbs background scattering from surfaces and particles, while much of the Doppler-broadened Rayleigh scattering is not absorbed by the iodine transition; the gas temperature can then be deduced from the measured transmission of the molecular Rayleigh scattering. For demonstration purposes and to evaluate the accuracy of the technique, we employed a near-adiabatic hydrogen-air flame. The accuracy of the FRS measurements was investigated by comparing FRS-derived temperatures with those (1) calculated assuming adiabatic equilibrium conditions and (2) recorded with the CARS (coherent anti-Stokes Raman spectroscopy) technique. For the hydrogen-air flames, the FRS method gave temperatures within 2% of the expected value. The FRS thermometry instrument was then applied to a stagnation-flow, premixed methane-air flame; images recorded here demonstrate the utility of the FRS method for temperature imaging, particularly near surfaces. In this flow field, we compared the FRS temperatures with those from a one-dimensional model and investigated the radial extent of the uniform temperature region, to assess the assumption of one-dimensionality. In addition, we demonstrated the feasibility of simultaneous measurements of the temperature and velocity fields, the latter derived from the particle image velocimetry technique.

  18. Development of High Spectral Resolution Technique for Registration Quasielastic Light Scattering Spectra Including Rayleigh and Brillouin Scattering as a Diagnostic Tool in Materials Characterization

    DTIC Science & Technology

    2007-11-02

    develop and build an optical device, fitted to a Fabry - Perot interferometer, to perform high-resolution quasieleastic light scattering spectroscopy...scattering spectra based on the use of a scanning by gas pressure Fabry - Perot interferometer coupled to the double grating monochromator...8a. Technical Progress We have designed and built new special metallic box with two optical windows for the Fabry - Perot interferometer and fine

  19. 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.

  20. Rayleigh wave scattering from sessile droplets

    NASA Astrophysics Data System (ADS)

    Quintero, R.; Simonetti, F.

    2013-10-01

    Radiation of energy by large-amplitude leaky Rayleigh waves is regarded as one of the key physical mechanisms regulating the actuation and manipulation of droplets in surface acoustic wave (SAW) microfluidic devices. The interaction between a SAW and a droplet is highly complex and is presently the subject of extensive research. This paper investigates the existence of an additional interaction mechanism based on the propagation of quasi-Stoneley waves inside sessile droplets deposited on a solid substrate. In contrast with the leaky Rayleigh wave, the energy of the Stoneley wave is confined within a thin fluid layer in contact with the substrate. The hypothesis is confirmed by three-dimensional finite element simulations and ultrasonic scattering experiments measuring the reflection of Rayleigh waves from droplets of different diameters. Moreover, real-time monitoring of the droplet evaporation process reveals a clear correlation between the droplet contact angle and the spectral information of the reflected Rayleigh signal, thus paving the way for ultrasonic measurements of surface tension.

  1. Filtered Rayleigh Scattering Measurements in a Buoyant Flow Field

    DTIC Science & Technology

    2008-03-01

    John William Strutt , the third Baron of Rayleigh , or more commonly known as Lord Rayleigh , was the first to offer a correct explanation of the...FILTERED RAYLEIGH SCATTERING MEASUREMENTS IN A BUOYANT FLOW FIELD         THESIS       Steven Michael Meents, Captain, USAF...AFIT/GAE/ENY/08-M22 FILTERED RAYLEIGH SCATTERING MEASUREMENTS IN A BUOYANT FLOW FIELD THESIS Presented to the Faculty Department of Aeronautics

  2. In situ characterization of nanoparticles using Rayleigh scattering

    DOE PAGES

    Santra, Biswajit; Shneider, Mikhail N.; Car, Roberto

    2017-01-10

    Here, we report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C60 at the expected concentrations of synthesis conditions in the arc periphery. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population frommore » the evolution of the scattered intensity. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols.« less

  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. Spontaneous inelastic Rayleigh scattering in optical fibers.

    PubMed

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

    2013-02-15

    Rayleigh scattering (RS) adds noise to signals that are transmitted over optical fibers and other optical waveguides. This noise can be the dominant noise source in a range between 10 Hz and 100 kHz from the carrier and can seriously degrade the performance of optical systems that require low close-in noise. Using heterodyne techniques, we demonstrate that the backscattered close-in noise spectrum in optical fibers is symmetric about the carrier and grows linearly with both input power and fiber length. These results indicate that the RS is spontaneous and is due to finite-lifetime thermal fluctuations in the glass.

  6. An investigation on the interaction of DNA with hesperetin/apigenin in the presence of CTAB by resonance Rayleigh light scattering technique and its analytical application

    NASA Astrophysics Data System (ADS)

    Bi, Shuyun; Wang, Yu; Pang, Bo; Yan, Lili; Wang, Tianjiao

    2012-05-01

    Two new systems for measuring DNA at nanogram levels by a resonance Rayleigh light scattering (RLS) technique with a common spectrofluorometer were proposed. In the presence of cetyltrimethylammonium bromide (CTAB), the interaction of DNA with hesperetin and apigenin (two effective components of Chinese herbal medicine) could enhance RLS signals with the maximum peak at 363 and 433 nm respectively. The enhanced intensity of RLS was directly proportional to the concentration of DNA in the range of 0.022-4.4 μg mL-1 for DNA-CTAB-hesperetin system and 0.013-4.4 μg mL-1 for DNA-CTAB-apigenin system. The detection limit was 2.34 ng mL-1 and 2.97 ng mL-1 respectively. Synthetic samples were measured satisfactorily. The recovery of DNA-CTAB-hesperetin system was 97.3-101.9% and that of DNA-CTAB-apigenin system was 101.2-109.5%.

  7. A Rayleigh-Brillouin scattering spectrometer for ultraviolet wavelengths.

    PubMed

    Gu, Ziyu; Vieitez, M Ofelia; van Duijn, Eric-Jan; Ubachs, Wim

    2012-05-01

    A spectrometer for the measurement of spontaneous Rayleigh-Brillouin (RB) scattering line profiles at ultraviolet wavelengths from gas phase molecules has been developed, employing a high-power frequency-stabilized UV-laser with narrow bandwidth (2 MHz). The UV-light from a frequency-doubled titanium:sapphire laser is further amplified in an enhancement cavity, delivering a 5 W UV-beam propagating through the interaction region inside a scattering cell. The design of the RB-scattering cell allows for measurements at gas pressures in the range 0-4 bars and at stably controlled temperatures from -30 °C to 70 °C. A scannable Fabry-Perot analyzer with instrument resolution of 232 MHz probes the RB profiles. Measurements on N(2) and SF(6) gases demonstrate that the high signal-to-noise ratio is achievable with the instrument at the 1% level at the peak amplitude of the scattering profile.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. Interaction of cetylpyridine bromide with nucleic acids and determination of nucleic acids at nanogram levels based on the enhancement of resonance Rayleigh light scattering.

    PubMed

    Liu, Rutao; Yang, Jinghe; Wu, Xia

    2002-07-01

    Resonance Rayleigh light scattering (RRLS) spectra of cetylpyridine bromide (CPB)-nucleic acid system and their analytical application have been first studied. The effective factors and optimum conditions of the reaction have been investigated. After CPB and nucleic acid are mixed together, a new absorption peak located at 300 nm appeared, which is due to the formation of new ion associate of CPB-nucleic acid. The new associate can result in two apparent RRLS peaks at 310-400 and 460-480 nm. The RRLS peak of the corrected spectra located at 290-350 nm, which indicate that the RRLS is originated from the absorption of CPB-nucleic acid associate. The peak at 460-480 nm disappears in the corrected RRLS spectra, which indicated that this peak is originated from the strong line emission of the Xe lamp. Under the optimum conditions, the enhanced intensity of RRLS is proportional to the concentration of nucleic acid in the range of 5.0 x 10(-9)-5.0 x 10(-5) g ml(-1) for calf thymus DNA (ctDNA), 1.0 x 10(-8)-4.0 x 10(-5) g ml(-1) for fish sperm DNA (fsDNA) and 1.0 x 10(-8)-5.0 x 10(-5) g ml(-1) for yeast RNA (yRNA). The detection limits (S/N = 3) are 4.3, 8.7 and 7.4 ng ml(-1), respectively. Synthetic samples were determined satisfactorily.

  13. 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.

  14. 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.

  15. DSMC simulation of Rayleigh-Brillouin scattering in binary mixtures

    NASA Astrophysics Data System (ADS)

    Bruno, Domenico; Frezzotti, Aldo; Ghiroldi, Gian Pietro

    2016-11-01

    Rayleigh-Brillouin scattering spectra (RBS) in dilute gas mixtures have been simulated by the Direct Simulation Monte Carlo method (DSMC). Different noble gas binary mixtures have been considered and the spectra have been simulated adopting the hard sphere collision model. It is suggested that DSMC simulations can be used in the interpretation of light scattering experiments in place of approximate kinetic models. Actually, the former have a firmer physical ground and can be readily extended to treat gas mixtures of arbitrary complexity. The results obtained confirm the capability of DSMC to predict experimental spectra and clears the way towards the simulation of polyatomic gas mixtures of interest for actual application (notably, air) where tractable kinetic model equations are still lacking.

  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. 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.

  18. 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.

  19. 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%.

  20. Individual TiO2 nanocrystals probed by resonant Rayleigh scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Honda, Mitsuhiro; Saito, Yuika; Kawata, Satoshi

    2014-11-01

    Individual titanium dioxide (TiO2) nanocrystals with bandgaps in the deep ultraviolet (DUV) wavelength range were investigated using resonant Rayleigh scattering spectroscopy. A microscopy system that was switchable from dark-field imaging to scattering spectroscopy was specifically constructed for a broadband UV light source. Weak Rayleigh scattering from a single nanocrystal a few nanometers in size was obtained through the UV excitation resonance and high positional reproducibility of the switching optics. Individual nanocrystals exhibited specific intrinsic bandgaps depending on their size, shape, and crystallinity, greatly affecting their photocatalytic efficiency.

  1. Single-Shot Spectrally Resolved UV Rayleigh Scattering Measurements in High Speed Flow

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1996-01-01

    A single-shot UV molecular Rayleigh scattering technique to measure velocity in high speed flow is described. The beam from an injection-seeded, frequency quadrupled Nd:YAG laser (266 nm) is focused to a line in a free air jet with velocities up to Mach 1.3. Rayleigh scattered light is imaged through a planar mirror Fabry-Perot interferometer onto a Charged Coupled Device (CCD) array detector. Some laser light is also simultaneously imaged through the Fabry-Perot to provide a frequency reference. Two velocity measurements are obtained from each image. Multiple-pulse data are also given. The Rayleigh scattering velocity data show good agreement with velocities calculated from isentropic flow relations.

  2. Demonstration and Analysis of Filtered Rayleigh Scattering Flow Field Diagnostic System

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    Filtered Rayleigh Scattering (FRS) is a diagnostic technique which measures velocity, temperature, and pressure by determining Doppler shift, total intensity, and spectral line shape of laser induced Rayleigh-Brillouin scattering. In the work reported here, this is accomplished by using a narrow line width, injection seeded Nd-YAG laser sheet to induce Rayleigh-Brillouin scattering from a gas flow. This light is passed through an optical notch filter, and transmitted light is imaged onto an intensified charge coupled display (CCD) camera. By monitoring the grayscale value at a particular pixel while the laser frequency is tuned, the convolution between the Rayleigh-Brillouin scattering profile and the filter transmission profile is attained. Since the filter profile can be independently measured, it can be deconvolved from the measuring signal, yielding the Rayleigh-Brillouin scattering profile. From this profile, flow velocity, temperature, and pressure are determined. In this paper the construction and characterization of the optical notch filter and a newly developed frequency apparatus are discussed.

  3. 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

  4. Electric field autocorrelation functions for beginning multiple rayleigh scattering.

    PubMed

    Lock, J A

    2001-08-20

    The polarization-resolved electric field autocorrelation function for p-order scattering was derived from the order-of-scattering solution of the exact equations for electromagnetic multiple Rayleigh scattering and was calculated for 2 scattering-angle dependence of the p-order autocorrelation function approximately decoupled from the delay-time dependence for p ? 3. The polarization-channel and the scattering-angle dependence were analytically calculated, and the delay-time dependence was analytically approximated. The resulting analytical model for the polarization-resolved autocorrelation function for beginning multiple Rayleigh scattering was then tested against experimental autocorrelation data. The data were found to be well fitted by the model.

  5. Electric Field Autocorrelation Functions for Beginning Multiple Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Lock, James A.

    2001-08-01

    The polarization-resolved electric field autocorrelation function for p -order scattering was derived from the order-of-scattering solution of the exact equations for electromagnetic multiple Rayleigh scattering and was calculated for 2 p 6 for particles undergoing diffusive motion in an idealized sample cell. It was found that the polarization-channel and the scattering-angle dependence of the p -order autocorrelation function approximately decoupled from the delay-time dependence for p ~ 3 . The polarization-channel and the scattering-angle dependence were analytically calculated, and the delay-time dependence was analytically approximated. The resulting analytical model for the polarization-resolved autocorrelation function for beginning multiple Rayleigh scattering was then tested against experimental autocorrelation data. The data were found to be well fitted by the model.

  6. 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.

  7. Rayleigh scattering in few-mode optical fibers

    PubMed Central

    Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang

    2016-01-01

    The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation. PMID:27775003

  8. Rayleigh scattering in few-mode optical fibers.

    PubMed

    Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang

    2016-10-24

    The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation.

  9. Rayleigh scattering in few-mode optical fibers

    NASA Astrophysics Data System (ADS)

    Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang

    2016-10-01

    The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation.

  10. Rayleigh x-ray scattering from many-electron atoms and ions

    NASA Astrophysics Data System (ADS)

    Surzhykov, A.; Yerokhin, V. A.; Stöhlker, Th; Fritzsche, S.

    2015-07-01

    A theoretical analysis is presented for the elastic Rayleigh scattering of x-rays by many-electron atoms and ions. Special emphasis is placed on the angular distribution and linear polarization of the scattered photons for the case when the incident light is completely (linearly) polarized. Based on second-order perturbation theory and the independent particle approximation, we found that the Rayleigh angular distribution is strongly affected by the charge state and shell structure of the target ions or atoms. This effect can be observed experimentally at modern synchrotron facilities and might provide further insight into the structure of heavy atomic systems.

  11. 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.

  12. Temperature retrieval error in Rayleigh-Brillouin scattering using Tenti's S6 kinetic model

    NASA Astrophysics Data System (ADS)

    Wu, Lei; Reese, Jason M.; Zhang, Yonghao

    2016-11-01

    The Rayleigh-Brillouin spectrum of light scattered by gas density fluctuations contains information about the gas temperature. This information can be retrieved by comparing experimentally measured spectra with theoretical line shapes determined from the linearized Boltzmann equation. However, the linearized Boltzmann equation is difficult to solve so Tenti's S6 kinetic model has been widely used for several decades because of its simplicity. In this paper, the linearized Boltzmann equation is solved by the efficient fast spectral method, and the temperature retrieval error associated with the Tenti's S6 model is systematically investigated for both spontaneous and coherent Rayleigh-Brillouin scattering, for different gas rarefaction and intermolecular potentials. Our results indicate useful calibrations for laser technologies that use Rayleigh-Brillouin scattering to profile for gas temperatures with high accuracy.

  13. 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.

  14. Spectrally resolved Rayleigh scattering diagnostic for hydrogen-oxygen rocket plume studies

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.; Zupanc, F. J.; Schneider, S. J.

    1991-01-01

    A Rayleigh scattering diagnostic has been developed to measure gas density, temperature, and velocity in the exhaust plume of 100 N thrust class hydrogen-oxygen rockets. The spectrum of argon-ion laser light scattered by the gas molecules in the plume (predominantly water vapor) is measured with a scanning Fabry-Perot interferometer. The gas density is determined from the total scattered power, the gas temperature from the spectral width, and the velocity from the shift in the peak of the spectrum from the frequency of the incident laser light. The diagnostic has been demonstrated in a rocket test cell and a discussion of results is given.

  15. Large-scale inhomogeneity in sapphire test masses revealed by Rayleigh scattering imaging

    NASA Astrophysics Data System (ADS)

    Yan, Zewu; Ju, Li; Eon, François; Gras, Slawomir; Zhao, Chunnong; Jacob, John; Blair, David G.

    2004-03-01

    Rayleigh scattering in test masses can introduce noise and reduce the sensitivity of laser interferometric gravitational wave detectors. In this paper, we present laser Rayleigh scattering imaging as a technique to investigate sapphire test masses. The system provides three-dimensional Rayleigh scattering mapping of entire test masses and quantitative evaluation of the Rayleigh scattering coefficient. Rayleigh scattering mapping of two sapphire samples reveals point defects as well as inhomogeneous structures in the samples. We present results showing significant non-uniform scattering within two 4.5 kg sapphire test masses manufactured by the heat exchanger method.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Rayleigh scattering and nonlinear inversion of elastic waves

    SciTech Connect

    Gritto, Roland

    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 -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 kpR = 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.

  1. 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.

  2. Filtered Rayleigh scattering based measurements in compressible mixing layers

    NASA Technical Reports Server (NTRS)

    Elliott, G. S.; Samimy, M.; Arnette, S. A.

    1992-01-01

    Results are presented of experiments in which a Rayleigh-scattering-based technique was used to make quantitative planar measurements in the compressible free shear layers. To this end, the absorption characteristics of the iodine molecular filter were investigated, and initial planar density measurements in M(c) = 0.51 shear layer were performed. The preliminary results presented here demonstrate the validity of the measurement technique.

  3. Light scattering from nonspherical airborne particles: Experimental and theoretical comparisons

    NASA Astrophysics Data System (ADS)

    Hirst, Edwin; Kaye, Paul H.; Guppy, John R.

    1994-10-01

    Spatial intensity distribution of laser light scattered by airborne hazardous particles such as asbestos fiber is studied to classify particles shape and size. Theoretical treatment is based on Rayleigh-Gans formalism. Theoretical and experimental data are in good agreement.

  4. Experimental study on stimulated Rayleigh scattering in optical fibers.

    PubMed

    Zhu, Tao; Bao, Xiaoyi; Chen, Liang; Liang, Hao; Dong, Yongkang

    2010-10-25

    The linewidth, the threshold, and frequency shift of the stimulated Rayleigh scattering (STRS) in single mode fiber (SMF-28e), large effective area fiber (LEAF) and polarization maintaining fiber (PMF) have been studied using heterodyne detection to separate the Brillouin scattering with a fiber laser for the first time to the best of our knowledge. Experimental results show that the linewidth of STRS and spontaneous Rayleigh scattering are ~9 kHz, ~10 kHz, and ~11 kHz, and ~25 kHz, ~30 kHz, and ~27 kHz for SMF-28e, LEAF and PMF, respectively. The threshold power for STRS for 2 km SMF-28e, 7 km LEAF, and 100 m PMF are 11 dBm, 4.5 dBm and 16.5 dBm, respectively. The measured Rayleigh gain coefficient is a 2 × 10(-13) m/W for SMF-28e. Also, weak frequency shift could be observed when input power is large enough before SBS occurred. Because of the properties of narrower bandwidth and lower threshold power of STRS in fibers, some of applications, such as narrower filter, could be realized.

  5. 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.

  6. 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.

  7. Depolarization of laser beam propagating through atmosphere based on multiple Rayleigh scattering model

    NASA Astrophysics Data System (ADS)

    Zhang, Dai; Hao, Shiqi; Wang, Lei; Zhao, Qi

    2016-10-01

    An analytical formula model which is used to describe laser beam's depolarization characteristics is solved based on multiple Rayleigh scattering model. Firstly, by using Stokes vector to characterize intensity and polarization, while at the same time using Mueller matrix and rotation matrix to characterize polarization changing in scattering procedure, a single scattering model is built. Then, a multiple scattering model is built considering the effects of atmospheric absorbing and scattering attenuation. The received light's Stokes vectors through multiple scattering procedure are separately solved. At last, on the basis of multiple scattering vectors, the depolarization characteristics of laser beam propagation through atmosphere are estimated though calculating ratio of depolarization and polarized angle shifting. The numerical analysis based on analytical conclusion of this paper shows that for a horizontal polarized laser beam, its ratio of depolarization is about 1% and polarized angle shifting is about 0.3° when propagates through atmosphere and arrives into the receiver on the ground, and both the above characteristics have only a small change compared with the change of cloud's depth. The findings of these research show that Rayleigh scattering from atmosphere has a weak effect on the laser beam's polarization status. The multiple scattering model and Stokes vector analytical formulas raised in the paper could also be used to study the depolarization characteristics of ellipse polarized laser beam and partially polarized laser beam propagating through atmosphere. The research findings of this paper will have theoretical guiding significances in the domain of laser communication, laser detection and laser imaging.

  8. Time Resolved Filtered Rayleigh Scattering Measurement of a Centrifugally Loaded Buoyant Jet

    DTIC Science & Technology

    2011-03-01

    filter along with the transmitted Rayleigh scattering signal [8]. In their study on atomic and molecular notch filters, Miles et al. present...light (broadened and shifted) fell outside the absorption well of the filter while ensuring near total absorbtion of the incident signal itself...Yalin, A.P, Tang, Z, Zaidi, S. H, and Forkey, J.N., “Flow Field Imaging through Sharp-edged Atomic and Molecular ‘Notch’ Filters ”, Measurement

  9. 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.

  10. [Research on detecting concentration of serum protein based on resonance Rayleigh scattering].

    PubMed

    Wang, Gao; Feng, Qiao-Ling; Xue, Zhong-Jin; Li, Yang-Jun; Zhou, Han-Chang

    2013-03-01

    The resonance Rayleigh scattering spectral detection system was designed based on the 2, 9, 16, 23-tetracarboxylate-phthalocyanine zinc and protein system. In the system, excitation light source is 405 nm wide band gap semiconductor lasers, and monochromator is 475 nm narrow-band band-pass filter, and the detector is low-noise and high-gain photoelectric amplifier based on blue-ray enhanced photodiode. Experiment shows that, the solution's strong absorption wavelength is near 420 nm. Under the action of incentive light, resonance Rayleigh scattering is generated at the resonant wavelength, and the scattering intensity is proportional to the protein content. The system uses 2, 9, 16, 23-tetracarboxylate as the spectrum probe to determine the concentration of serum proteins by resonance Rayleigh scattering method. Its linear detection range is 10 - 50 mg.mL-1, and its detection limit is 0. 001 mg.mL-1. The newly developed device for detecting concentration of the serum protein has the advantages of small size, low cost, low power consumption, and being easy to use.

  11. 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.

  12. Rocket plume flowfield characterization using laser Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Zupanc, Frank J.; Weiss, Jonathan M.

    1992-07-01

    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.

  13. 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.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2002-04-01

    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.

  16. 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.

  17. 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.

  18. Rayleigh scattering and the internal coupling parameter for arbitrary particle shapes

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

    A general method for calculating the Rayleigh scattering by a particle of arbitrary shape is introduced. Although analytical solutions for Rayleigh scattering exist for spheres and ellipsoids, analytical solutions for more complicated shapes don't exist. We find that in general the Rayleigh differential cross section goes as k4V2| α (m) | 2 where k = 2 π / λ and λ is the wavelength, V is the volume of the particle and α (m) the average volume polarizability which is dependent on the shape and the complex index of refraction, m. We use existing computational techniques, the discrete dipole approximation (DDA) and the T-matrix method, to calculate the differential scattering cross section divided by k4 and plot it vs V2 to determine | α (m) | 2. Furthermore, we show that this leads to a general description of the internal coupling parameter ρarbitrary‧ = 2 πk V/A | α (m) | where A is the average projected area of the particle in the direction of incident light. It is shown that this general method makes significant changes in the analysis of scattering by particles of any size and shape.

  19. 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.

  20. Ultraviolet Rayleigh Scatter Imaging for Spatial Temperature Profiles in Atmospheric Microdischarges

    DTIC Science & Technology

    2014-09-01

    laser manufactured by Quantel. This Brilliant laser has a specification output of 330 mJ per pulse at its fundamental 1064 nm, 165 mJ per pulse at...using Rayleigh scattering of a pulsed ultraviolet laser . Scattering intensity images were used to generate a radial profile of translational...agreement with the Rayleigh translational temperature profiles. 15. SUBJECT TERMS ultraviolet laser , Rayleigh scatter microdischarge, translational

  1. 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.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  4. 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.

  5. 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 D.

    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.

  6. Light Scattering from Exoplanet Oceans and Atmospheres

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    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 = 180deg, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30deg. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74deg; 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 = 90deg, 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. This research was funded by the NASA Astrobiology Institute, the University of Washington Virtual Planetary Laboratory, and the Penn State Astrobiology Institute. Authors M. Zugger, J. Kasting, and D. Williams are members of the Penn State Center for Exoplanets and Habitable Worlds.

  7. 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.

  8. Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Shirley, John A.; Winter, Michael

    1993-01-01

    An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

  9. 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).

  10. Nonequilibrium fluctuations from a nematic under a thermal gradient and a gravity field*. II. Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Camacho, Jorge F.; Rodríguez, Rosalío F.

    2017-02-01

    The fluctuating hydrodynamic treatment developed in the previous article for a nematic liquid crystal under the influence of a thermal gradient α and a uniform gravity field g, is used to calculate its Rayleigh light scattering spectrum. We find that the dissipative thermal gradient force enhances the Rayleigh-line intensity which varies as k -4 with the fluctuations of the wave number k. The Rayleigh line consists of three central Lorentzians, two of which are determined by the visco-heat modes coupling the entropy and director fluctuations, which is a pure non-equilibrium effect. The third Lorentzian is due only to director fluctuations. We find that the former peaks contain the Rayleigh wings owing to the orientational fluctuations of the aniosotropic molecules. It is also shown that the obtained spectrum reduces to the known equilibrium spectrum of a nematic and to that of a simple fluid. For the particular case in which the decay rates are diffusive, we calculate and plot the amplitudes of non-equilibrium fluctuations of the dynamic structure factor as a function of | α|2/ k 4, and also, the intermediate function in the equilibrium and non-equilibrium states.

  11. 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.

  12. 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.

  13. 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.

  14. Inelastic Light Scattering Processes

    NASA Technical Reports Server (NTRS)

    Fouche, Daniel G.; Chang, Richard K.

    1973-01-01

    Five different inelastic light scattering processes will be denoted by, ordinary Raman scattering (ORS), resonance Raman scattering (RRS), off-resonance fluorescence (ORF), resonance fluorescence (RF), and broad fluorescence (BF). A distinction between fluorescence (including ORF and RF) and Raman scattering (including ORS and RRS) will be made in terms of the number of intermediate molecular states which contribute significantly to the scattered amplitude, and not in terms of excited state lifetimes or virtual versus real processes. The theory of these processes will be reviewed, including the effects of pressure, laser wavelength, and laser spectral distribution on the scattered intensity. The application of these processes to the remote sensing of atmospheric pollutants will be discussed briefly. It will be pointed out that the poor sensitivity of the ORS technique cannot be increased by going toward resonance without also compromising the advantages it has over the RF technique. Experimental results on inelastic light scattering from I(sub 2) vapor will be presented. As a single longitudinal mode 5145 A argon-ion laser line was tuned away from an I(sub 2) absorption line, the scattering was observed to change from RF to ORF. The basis, of the distinction is the different pressure dependence of the scattered intensity. Nearly three orders of magnitude enhancement of the scattered intensity was measured in going from ORF to RF. Forty-seven overtones were observed and their relative intensities measured. The ORF cross section of I(sub 2) compared to the ORS cross section of N2 was found to be 3 x 10(exp 6), with I(sub 2) at its room temperature vapor pressure.

  15. 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.

  16. Filtered Rayleigh scattering measurements in supersonic/hypersonic facilities

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Preliminary measurements are presented of flow field properties in Mach 3 and Mach 5 flows using filtered Rayleigh scattering. Filter properties have been characterized by high resolution spectroscopy in order to optimize the selection of laser frequency and filter operating conditions, as well as for the development of an accurate filter modeling program. An optimized filter is used the background suppression feature of this technique to image the boundary layer structure in a Mach 3 high Reynolds number facility and the shock structure in a Mach 5 overexpanded jet. This had been achieved using a visible laser source. By frequency scanning the laser, time-averaged velocity measurements in the Mach 3 and Mach 5 flows are made. Data acquisition at 10 torr and below indicates that this approach can be extrapolated for use in hypersonic flow facilities and is applicable as an in-flight optical air data device for hypersonic vehicles.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. Fiber optic quench detection via optimized Rayleigh Scattering in high-field YBCO accelerator magnets

    SciTech Connect

    Flanagan, Gene

    2016-02-17

    Yttrium barium copper oxide (YBCO) coated conductors are known for their ability to operate in the superconducting state at relatively high temperatures, even above the boiling point of liquid nitrogen (77 K). When these same conductors are operated at lower temperatures, they are able to operate in much higher magnetic fields than traditional superconductors like NiTi or Nb3Sn. Thus, YBCO superconducting magnets are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber optic sensing, based upon Rayleigh scattering, has the potential for spatial resolution approaching the wavelength of light, or very fast temporal resolution at low spatial resolution, and a continuum of combinations in between. This project has studied, theoretically and experimentally, YBCO magnets and Rayleigh scattering quench detection systems to demonstrate feasibility of the systems for YBCO quench protection systems. Under this grant an experimentally validated 3D quench propagation model was used to accurately define the acceptable range of spatial and temporal resolutions for effective quench detection in YBCO magnets and to evaluate present-day and potentially improved YBCO conductors. The data volume and speed requirements for quench detection via Rayleigh scattering required the development of a high performance fiber optic based quench detection/data acquisition system and its integration with an existing voltage tap/thermo-couple based system. In this project, optical fibers are tightly co-wound into YBCO magnet coils, with the fiber on top of the conductor as turn-to-turn insulation. Local changes in the temperature or strain of the conductor are sensed by the optical fiber, which is in close thermal and mechanical contact with the conductor. Intrinsic imperfections in the fiber reflect Rayleigh

  5. 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

  6. 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.

  7. Hyper-Rayleigh scattering of protein-modified gold nanoparticles.

    PubMed

    Zhang, Chun Xiu; Zhang, Yu; Wang, Xin; Tang, Zu Ming; Lu, Zu Hong

    2003-09-01

    The nonlinear optical properties of protein-modified gold nanoparticles has been studied by the hyper-Rayleigh scattering (HRS) technique. HRS signals from the nanoparticles coated with goat-anti-human IgG have been obtained when pumped with a laser pulse with a wavelength of 1064 nm. The HRS signals of gold nanoparticles with IgG were larger than those of bare gold nanoparticles. This can be explained by a noncentrosymmetric effect. It was also found that the HRS signals from the IgG-coated gold nanoparticles could be greatly increased when the antigen was added due to gold nanoparticle aggregation. Our experiment found that the HRS method could produce a measurable signal with 10 microg/ml antigen added, while the colorimetric method using UV spectrum detection required 100 microg/ml of added antigen. The results show that the HRS measurement of immunogold nanoparticles could become a potential immunoassay in determining small levels of antigen in aqueous samples.

  8. Resonance Rayleigh scattering for detection of proteins in HPLC.

    PubMed

    Lu, Xin; Luo, Zhihui; Liu, Chengwei; Zhao, Shulin

    2008-09-01

    An HPLC-resonance Rayleigh scattering (RRS) (HPLC-RRS) detection system is described for separation and detection of proteins. This system is based on the modification of a commercial HPLC instrument involving the addition of a pump and a T-shaped interface, and a common fluorescence detector was used for detection. The detection principle is based on the change of RRS intensity of the ion-association complex formed from biebrich scarlet (BS) and protein. The RRS signal was detected at lambdaex=lambdaem=376 nm. The utility of the presented method was demonstrated by the separation and determination of four proteins involving cytochrome (Cyt-c), lysozyme (Lys), HSA, and gamma-globulin (gamma-Glo). An LOD of 0.2-1.0 microg/mL was reached and a linear range was found between peak area and concentration in the range of 0.20-3.0 microg/mL for Cyt-c, 0.25-2.5 microg/mL for Lys, 1.5-10 microg/mL for HSA, and 2.0-15 microg/mL for gamma-Glo, with linear regression coefficients all above 0.99. The method presented has been applied to determine HSA and gamma-Glo in human serum samples synchronously.

  9. 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.

  10. 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.

  11. On the measurement of Rayleigh scattering by gases at 6328A

    NASA Technical Reports Server (NTRS)

    SHARDANAND; Gupta, S. K.

    1973-01-01

    The problem of laboratory measurements of Rayleigh scattering and depolarization ratio for atoms and molecules in the gaseous state is described. It is shown that, if the scattered radiation measurements are made at two angles, the normal depolarization ratio cannot be determined meaningfully. However, from scattering measurements, the Rayleigh scattering cross sections can be determined accurately. The measurements of Raleigh scattering from He, H2, Ar, O2, and N2 for unpolarized radiation at 6328A are reported and compared with similar measurements at 6943 and 1215.7A.

  12. 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.

  13. 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.

  14. High-spectral-resolution stimulated Rayleigh-Brillouin scattering at 1 microm.

    PubMed

    Faris, G W; Gerken, M; Jirauschek, C; Hogan, D; Chen, Y

    2001-12-01

    We have demonstrated stimulated Rayleigh-Brillouin scattering at a wavelength of 1.064 microm , using an injection-seeded Nd:YAG laser as a pump laser and a tunable diode laser as a probe laser. Spectra with a good signal-to-noise ratio are obtained despite the low probe-beam power and small gain coefficient in the infrared. Stimulated Rayleigh scattering is readily observable in organic and many other liquids because of absorption by the OH and CH overtone or combination bands. The absorption also causes an asymmetry in the stimulated Brillouin peak. A Rayleigh linewidth of 8 MHz is measured with this approach.

  15. 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.

  16. 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.

  17. 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.

  18. A molecular Rayleigh scattering setup to measure density fluctuations in thermal boundary layers

    NASA Astrophysics Data System (ADS)

    Panda, J.

    2016-12-01

    A Rayleigh scattering-based density fluctuation measurement system was set up inside a low-speed wind tunnel of NASA Ames Research Center. The immediate goal was to study the thermal boundary layer on a heated flat plate. A large number of obstacles had to be overcome to set up the system, such as the removal of dust particles using air filters, the use of photoelectron counting electronics to measure low intensity light, an optical layout to minimize stray light contamination, the reduction in tunnel vibration, and an expanded calibration process to relate photoelectron arrival rate to air density close to the plate surface. To measure spectra of turbulent density fluctuations, a two-PMT cross-correlation system was used to minimize the shot noise floor. To validate the Rayleigh measurements, temperature fluctuations spectra were calculated from density spectra and then compared with temperature spectra measured with a cold-wire probe operated in constant current mode. The spectra from the downstream half of the plate were found to be in good agreement with cold-wire probe, whereas spectra from the leading edge differed. Various lessons learnt are discussed. It is believed that the present effort is the first measurement of density fluctuations spectra in a boundary layer flow.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Analysis of the spontaneous Rayleigh-Brillouin scattering spectra of N2

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Xia, Ruxiao; He, Xingdao; Zhang, Xinyi; Yu, Huan

    2016-10-01

    The influence of different pressures, temperatures, scattering angles and incident wavelengths to the relative intensity of the Brillouin peaks to the Rayleigh peak and the Brillouin shift in the spontaneous Rayleigh-Brillouin scattering (SRBS) spectra of N2 is analyzed by using the Tenti S6 model. A system for detecting the SRBS spectra of gas is also introduced in this paper. The SRBS spectra of N2 at different pressures with the incident wavelength of 532nm, the temperature of 300K and the scattering angle of 90° have been measured, the experiment results are well agreed to the simulations.

  5. Mesospheric temperatures from Rayleigh scattering measurements by the WINDII instruments on UARS

    NASA Astrophysics Data System (ADS)

    Evans, W. F. J.; Laframboise, L. R.; Shepherd, G. G.

    1994-09-01

    The WINDII instrument on the UARS satellite has several filter channels. In each of these channels, Rayleigh scattering from the earth's atmosphere is measured in the daytime. The Rayleigh scattering component varies quasi-exponentially with altitude with the scale height of the atmosphere. This data first must be corrected for the relevant baffle scattering component. After several corrections, temperatures from about 75 to 110 km can be measured. The development of the algorithm is discussed and several typical temperature profiles are presented. An analysis of the errors and comparisons with current upper atmosphere models are considered. The presence of nontilucent clouds is indicated in several August profiles in the northern hemisphere.

  6. Review of light scattering literature

    NASA Astrophysics Data System (ADS)

    Potts, Marie K.

    1994-06-01

    This report reviews the recent literature of static and dynamic light scattering of dilute and semidilute polymer solutions and gels, as obtained from the Chemical Abstracts Macromolecular Sections, and an electronic literature search. In general, this review has been confined to the interests of the Polymer Research Branch, specifically experimental light scattering studies of synthetic polymers in solution. In order to further limit the size of this review, light scattering for phase separation studies or particle size analysis have been excluded, as well as light scattering used strictly for size exclusion chromatography detection.

  7. 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

  8. Resonance enhanced dynamic light scattering.

    PubMed

    Plum, Markus A; Menges, Bernhard; Fytas, George; Butt, Hans-Jürgen; Steffen, Werner

    2011-01-01

    We present a novel light scattering setup that enables probing of dynamics near solid surfaces. An evanescent wave generated by a surface plasmon resonance in a metal layer is the incident light field in the dynamic light scattering experiment. The combination of surface plasmon resonance spectroscopy and dynamic light scattering leads to a spatiotemporal resolution extending a few hundred nanometers from the surface and from microseconds to seconds. The comparison with evanescent wave dynamic light scattering identifies the advantages of the presented technique, e.g., surface monitoring, use of metal surfaces, and biorelevant systems. For both evanescent wave geometries, we define the scattering wave vector necessary for the analysis of the experimental relaxation functions.

  9. Loss properties due to Rayleigh scattering in different types of fiber.

    PubMed

    Zhi, Wang; Guobin, Ren; Shuqin, Lou; Shuisheng, Jian

    2003-01-13

    The effects of fiber structure on Rayleigh scattering were investigated in detail. Some step-index fibers such as GeO2- and F-doped silica-based fibers and total-internal-reflection photonic crystal fiber are examined. The Rayleigh scattering loss (RSL) depends on the fiber materials and index profiles, and different types of fiber have different dependencies on those parameters because of the different optical power confinement factors in every layer. On the basis of these results, the RSL can be optimized by adjusting the fiber structure or by selecting different materials.

  10. 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.

  11. Eliminating Rayleigh and Raman Scattering in Three-Dimensional Fluorescence Spectroscopy by Kriging Interpolation

    NASA Astrophysics Data System (ADS)

    Yu, Sh.; Xiao, X.; Xu, G.

    2016-11-01

    In order to effectively eliminate Rayleigh and Raman scattering, a method based on Kriging interpolation is proposed, in which both the distance and the correlation between the scattering region and the nonscattering region are considered. The experimental results show that an unbiased estimation of the scattering region is achieved by this Kriging interpolation. Compared with other interpolation methods that use only the neighboring points, the performance of this method for eliminating the scattering region is much less sensitive to the scattering range that we set.

  12. Synthetic Fourier transform light scattering.

    PubMed

    Lee, Kyeoreh; Kim, Hyeon-Don; Kim, Kyoohyun; Kim, Youngchan; Hillman, Timothy R; Min, Bumki; Park, Yongkeun

    2013-09-23

    We present synthetic Fourier transform light scattering, a method for measuring extended angle-resolved light scattering (ARLS) from individual microscopic samples. By measuring the light fields scattered from the sample plane and numerically synthesizing them in Fourier space, the angle range of the ARLS patterns is extended up to twice the numerical aperture of the imaging system with unprecedented sensitivity and precision. Extended ARLS patterns of individual microscopic polystyrene beads, healthy human red blood cells (RBCs), and Plasmodium falciparum-parasitized RBCs are presented.

  13. 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

  14. Rayleigh-Brillouin scattering in SF6 in the kinetic regime

    NASA Astrophysics Data System (ADS)

    Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim

    2017-02-01

    Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2-5 bar and for a wavelength of λ = 403.0 nm. The high quality data are compared to a number of light scattering models in order to address the effects of rotational and vibrational relaxation. While the vibrational relaxation rate is so slow that vibration degrees of freedom remain frozen, rotations relax on time scales comparable to those of the density fluctuations. Therefore, the heat capacity, the thermal conductivity and the bulk viscosity are all frequency-dependent transport coefficients. This is relevant for the Tenti model that depends on the values chosen for these transport coefficients. This is not the case for the other two models considered: a kinetic model based on rough-sphere interactions, and a model based on fluctuating hydrodynamics. The deviations with the experiment are similar between the three different models, except for the hydrodynamic model at pressures p≲ 2bar . As all models are in line with the ideal gas law, we hypothesize the presence of real gas effects in the measured spectra.

  15. 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.

  16. Direct determination of polymyxin B sulfate using resonance Rayleigh scattering and resonance non-linear scattering methods with hexatungstate.

    PubMed

    Kong, Ling; Liu, Zhongfang; Liu, Shaopu; Wu, Limin; Tian, Fengling

    2014-02-01

    At pH 1.3-1.6, tungstate WO4(2-) , can be converted to hexatungstate W6 O19(2-) , which can react with positively charged polymyxin B sulfate (PMB) to result in enhancement of resonance Rayleigh scattering (RRS) and resonance non-linear scattering, including second order scattering and frequency doubling scattering. Linear relationships can be established between enhanced scattering intensity and PMB concentration. The detection limits (3σ) were 5.5 ng/mL (RRS), 10.1 ng/mL (second order scattering) and 34.6 ng/mL (frequency doubling scattering). The optimum reaction conditions, influencing factors and related analytical properties were tested. The interaction mechanism was investigated via absorption spectrum, circular dichroism spectra and atomic force microscopy imaging. The basis of scattering enhancement is discussed. PMB in eardrops, human serum and urine, were quantified satisfactorily by RRS.

  17. Automatic Rayleigh scattering mapping system for optical quality evaluation of test masses for gravity wave detectors

    NASA Astrophysics Data System (ADS)

    Yan, Zewu; Zhao, Chunnong; Ju, Li; Gras, Slawomir; Baringa, Pablo; Blair, David G.

    2005-01-01

    This article describes an automatic Rayleigh scattering mapping system (ARSMS), which enables quantitative high-resolution three-dimensional mapping of inhomogeneities in optical materials. The ARSMS allows large high-grade test mass samples for gravitational wave detectors to be evaluated to ensure that an adequate low level of scattering is achieved. The ARSMS combines proprietary camera software with data analysis software and control software to achieve fully automatic operation with graphical user interfaces. This article presents the instrument concept and examples of the output. Device mapping in all degrees of freedom is shown to be better than 0.5mm, with scattering sensitivity better than 0.5ppm/cm. This system is able to scan and map the Rayleigh scattering of large samples in both of cylindrical and rectangular samples using cylindrical and Cartesian coordinates.

  18. 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.

  19. Spatial temperature mapping of an atmospheric microdischarge using ultraviolet Rayleigh scatter imaging

    NASA Astrophysics Data System (ADS)

    Adams, S. F.; Caplinger, J. E.; Sommers, B. S.

    2015-04-01

    Spatially resolved temperature measurements within a microdischarge in atmospheric pressure air have been conducted using Rayleigh scattering of a pulsed ultraviolet laser. Rayleigh scatter images were used to generate highly resolved 1D and 2D profiles of translational temperature, with the analysis based on the ideal gas inverse relationship between temperature and gas density. The technique was shown to be practical to an upper gas temperature limit of approximately 2000 K. Rayleigh scattering results were compared to standard optical emission spectral analyses of {{\\text{N}}2}≤ft({{C}3}{{\\Pi}\\text{u}}\\to {{B}3}{{\\Pi}\\text{g}}\\right) bands, where the calculated rotational temperatures from emission agreed consistently with the peak translational temperatures within the microdischarge measured by Rayleigh laser scatter analyses. The results provide distinctive support of the assumption commonly applied for {{\\text{N}}2} discharges that the {{\\text{N}}2}≤ft({{C}3}{{\\Pi}\\text{u}}\\right) excited state has an identical rotational energy distribution as the {{\\text{N}}2}≤ft({{X}1}{Σ\\text{g}}\\right) ground state. The microdischarge investigated in this study was found to follow another common assumption for non-thermal discharges; that the translation and rotational temperatures are approximately equal to each other and the vibrational temperature is of a much higher value.

  20. Coherent Rayleigh-Brillouin scattering for in situ detection of nanoparticles and large molecules in gas and plasma

    NASA Astrophysics Data System (ADS)

    Gerakis, A.; Shneider, M. N.; Stratton, B. C.; Santra, B.; Car, R.; Raitses, Y.

    2016-09-01

    Laser-based diagnostics methods, such as Spontaneous and Coherent Rayleigh and Rayleigh-Brillouin scattering (SRBS and CRBS), can be used for in-situ detection and characterization of nanoparticle shape and size as well as their concentration in an inert gas atmosphere. We recently developed and tested this advanced diagnostic at PPPL. It was shown that the signal intensity of the CRBS signal depends on the gas-nanoparticle mixture composition, density and the polarizabilities of the mixture components. The measured results agree well with theoretical predictions of Refs. In this work, we report the application of this diagnostic to monitor nucleation and growth of nanoparticles in a carbon arc discharge. In support of these measurements, A time-dependent density functional theory was used to compute the frequency-dependent polarizabilities of various nanostructures in order to predict the corresponding Rayleigh scattering intensities as well as light depolarization. Preliminary results of measurements demonstrate that CRBS is capable to detect nanoparticles in volume. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

  1. Superlinear growth of Rayleigh scattering-induced intensity noise in single-mode fibers.

    PubMed

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

    2015-03-09

    Rayleigh scattering generates intensity noise close to an optical carrier that propagates in a single-mode optical fiber. This noise degrades the performance of optoelectronic oscillators and RF-photonic links. When using a broad linewidth laser, we previously found that the intensity noise power scales linearly with optical power and fiber length, which is consistent with guided entropy mode Rayleigh scattering (GEMRS), a third order nonlinear scattering process, in the spontaneous limit. In this work, we show that this behavior changes significantly with the use of a narrow linewidth laser. Using a narrow linewidth laser, we measured the bandwidth of the intensity noise plateau to be 10 kHz. We found that the scattered noise power scales superlinearly with fiber length up to lengths of 10 km in the frequency range of 500 Hz to 10 kHz, while it scales linearly in the frequency range of 10 Hz to 100 Hz. These results suggest that the Rayleigh-scattering-induced intensity noise cannot be explained by third-order nonlinear scattering in the spontaneous limit, as previously hypothesized.

  2. 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.

  3. 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

    2014-04-01

    We analyse 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.

  4. Highly sensitive ratiometric quantification of cyanide in water with gold nanoparticles via Resonance Rayleigh Scattering.

    PubMed

    Hernández, Yulán; Coello, Yves; Fratila, Raluca M; de la Fuente, Jesús M; Lionberger, Troy A

    2017-05-15

    A highly sensitive and selective ratiometric sensor for the quantification of cyanide (CN(-)) in aqueous samples has been developed using spherical gold nanoparticles (AuNPs) stabilized by polysorbate 40 (PS-40). Three different AuNP sizes (14, 40 and 80nm mean diameters) were used to evaluate the response of the sensor using both colorimetric and Resonance Rayleigh Scattering (RRS) detection schemes. The best results were obtained for the sensor using 40nm AuNPs, for which the limits of detection (LODs) were found to be 100nmolL(-1) in a benchtop instrument and 500nmolL(-1) by the naked eye, values well below the maximum acceptable level for drinking water (1.9µmolL(-1)) set by the World Health Organization (WHO). The practical use of the 40nm-AuNPs RRS sensor was demonstrated with the determination of CN(-) in drinking and fresh waters. Finally, the sensor was successfully implemented in a compact portable device consisting of two light-emitting diodes (LEDs) and a miniature spectrometer, turning this sensor into a very potent tool for its application as a quick routine field-deployable analytical method.

  5. 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.

  6. RAYLEIGH SCATTERING IN THE ATMOSPHERE OF THE WARM EXO-NEPTUNE GJ 3470B

    SciTech Connect

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

  7. [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

  8. 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.

  9. Reduction of double Rayleigh scattering noise in distributed Raman amplifiers employing higher-order pumping.

    PubMed

    Bolognini, Gabriele; Bononi, Alberto

    2009-04-27

    We present a theoretical study of the performance of distributed Raman amplifiers with higher order pumping schemes, focusing in particular on double Rayleigh scattering (DRS) noise. Results show an unexpected significant DRS noise reduction for pumping order higher than third, allowing for an overall performance improvement of carefully designed distributed amplifiers, ensuring a large optical signal-to-noise ratio improvement together with reduced DRS-induced penalties.

  10. Volumetric imaging of supersonic boundary layers using filtered Rayleigh scattering background suppression

    NASA Technical Reports Server (NTRS)

    Forkey, Joseph N.; Lempert, Walter R.; Bogdonoff, Seymour M.; Miles, Richard B.; Russell, G.

    1995-01-01

    We demonstrate the use of Filtererd Rayleigh Scattering and a 3D reconstruction technique to interrogate the highly three dimensional flow field inside of a supersonic inlet model. A 3 inch by 3 inch by 2.5 inch volume is reconstructed yielding 3D visualizations of the crossing shock waves and of the boundary layer. In this paper we discuss the details of the techniques used, and present the reconstructured 3D images.

  11. Application of coherent Rayleigh-Brillouin scattering for in situ nanoparticle and large molecule detection

    NASA Astrophysics Data System (ADS)

    Shneider, M. N.; Gimelshein, S. F.

    2013-04-01

    Feasibility of using coherent Rayleigh-Brillouin scattering for nanoparticle and large molecule diagnostics is assessed analytically and numerically through the solution of the Boltzmann equation. It has been shown that for particles of about 1 nm in diameter dispersed in a buffer gas, concentrations as small as 0.005% may be detected. The approach is expected to provide information on particle concentration with high spatial and temporal resolution.

  12. 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.

  13. 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.

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

    DOE PAGES

    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.

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

    SciTech Connect

    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. 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.

  17. Nonlinear light scattering in a carbon nanotube suspension

    SciTech Connect

    Mikheev, Gen M; Mogileva, T N; Bulatov, D L; Vanyukov, V V; Okotrub, Aleksandr V

    2010-01-31

    Nonlinear scattering of 1064-nm laser light in an aqueous suspension of purified carbon nanotubes has been studied in relation to their optical power limiting behaviour using z-scan measurements to simultaneously determine the energy and shape of the transmitted and 90{sup 0} circ-scattered pulses. The results indicate that the reduction in transmitted laser pulse energy with increasing incident power density is mainly due to the associated increase in scattered pulse energy. The shape, duration and time shift of the transmitted and 90{sup 0} circ-scattered pulses are intricate functions of incident power density. The data are interpreted in terms of thermally induced nonlinear and Rayleigh scattering processes at high and low incident power densities, respectively. (nonlinear optics phenomena)

  18. 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.

  19. A Theoretical Light Scattering Model of Nanoparticle Laser Tweezers

    NASA Technical Reports Server (NTRS)

    Lock, James A.

    2003-01-01

    Accomplishments this reporting period include: 1. derived, programmed, checked, and tested the Mie light scattering theory formulas for the radiation trapping force for both the on-axis and off-axis geometry of the trapping beam plus trapped spherical particle; 2. verified that the computed radiation trapping force for a freely propagating focused Gaussian laser beam incident on a spherical particle agrees with previous published calculations; 3. compared the small particle size and large particle size limits of the Mie calculation with the results of Rayleigh scattering theory and ray scattering theory, respectively and verified that the comparison is correct for Rayleigh scattering theory but found that ray theory omits an important light scattering effect included in the Mie theory treatment; 4. generalized the calculation of the radiation trapping force on a spherical particle in the on-axis geometry from a freely propagating focused Gaussian laser beam to the realistic situation of a Gaussian beam truncated and focused by a high numerical aperture oil-immersion microscope objective lens and aberrated by the interface between the microscope cover slip and the liquid-filled sample volume; and 5. compared the calculated radiation trapping force for this geometry with the results of previously published experiments and found that the agreement is better than when using previously developed theories.

  20. Exact Rayleigh scattering calculations for use with the Nimbus-7 Coastal Zone Color Scanner.

    PubMed

    Gordon, H R; Brown, J W; Evans, R H

    1988-03-01

    For improved analysis of Coastal Zone Color Scanner (CZCS) imagery, the radiance reflected from a planeparallel atmosphere and flat sea surface in the absence of aerosols (Rayleigh radiance) has been computed with an exact multiple scattering code, i.e., including polarization. The results indicate that the single scattering approximation normally used to compute this radiance can cause errors of up to 5% for small and moderate solar zenith angles. At large solar zenith angles, such as encountered in the analysis of high-latitude imagery, the errors can become much larger, e.g.,>10% in the blue band. The single scattering error also varies along individual scan lines. Comparison with multiple scattering computations using scalar transfer theory, i.e., ignoring polarization, show that scalar theory can yield errors of approximately the same magnitude as single scattering when compared with exact computations at small to moderate values of the solar zenith angle. The exact computations can be easily incorporated into CZCS processing algorithms, and, for application to future instruments with higher radiometric sensitivity, a scheme is developed with which the effect of variations in the surface pressure could be easily and accurately included in the exact computation of the Rayleigh radiance. Direct application of these computations to CZCS imagery indicates that accurate atmospheric corrections can be made with solar zenith angles at least as large as 65 degrees and probably up to at least 70 degrees with a more sensitive instrument. This suggests that the new Rayleigh radiance algorithm should produce more consistent pigment retrievals, particularly at high latitudes.

  1. Competition between stimulated Brillouin and thermal Rayleigh scattering in Au-nanorods/water system

    NASA Astrophysics Data System (ADS)

    Wu, Haopeng; Shi, Jiulin; Wang, Hongpeng; Qian, Jiacheng; Liu, Juan; He, Xingdao

    2015-04-01

    The use of a simple focused optical cell to present the competition between stimulated Brillouin scattering (SBS) and stimulated thermal Rayleigh scattering (STRS) has been investigated experimentally. An Au-nanorod/water sample as the scattering medium pumped by a pulsed narrow-linewidth second-harmonic Nd:YAG laser with ∼532 nm wavelength, ∼8 ns pulse duration, and 10 Hz repetition rate was used. Experimental results indicate that the absorption coefficient of Au-nanorod/water samples is important for the competition between SBS and STRS. When the absorption coefficient α is smaller than a critical value {{α }cr}, SBS will be dominant during the backward stimulated scattering process. By the same token, when the absorption coefficient α is larger than a critical value {{α }cr}, SBS will be greatly suppressed and STRS will be dominant.

  2. 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 .

  3. Experimental study of unsteady laminar and turbulent flame propagation in an enclosure by Rayleigh scattering

    SciTech Connect

    Tamai, R.; Shepherd, I.G.; Cheng, R.K.

    1992-09-01

    The Rayleigh scattering technique has been used to investigate the flame structure of unsteady propane/air flames propagating under quiescent and turbulent conditions initiated by three ignition methods: (1) conventional spark plug (2) pulse jet combustion (PJC) and (3) Pre-Chamber ignition (PCI). The Rayleigh signal obtained for the laminar cases are all characterized by a sharp transition associated with the large density change which occurs as leading flame front of the expanding flame kernel crosses the measurement point. This indicates that the local flame structures are independent of the ignition source and may be characterized as flamelets. The maximum burning rates deduced from the pressure records show that PJC and PCI increases the burning rate from two to three times above that of conventional spark ignition. The Rayleigh scattering signal obtained for the turbulent cases are also characterized by sharp transition. The wrinkled laminar flamelet model, therefore, provides a valid description of the flame structures for all these unsteady flames. For a given equivalence ratio, the maximum turbulent burning rate deduced for the three turbulent cases with different ignition sources are similar. This suggests that while PJC and PCI enhances burning rate when conditions in the chamber are quiescent, the enhancement is not significant when turbulence fluctuations are present. The PJC and PCI, however, are capable of igniting leaner conditions than the spark plug. This may be due to the injection process which initially disperses ignition sites to a larger volume at a faster rate.

  4. Long-range measurement of Rayleigh scatter signature beyond laser coherence length based on coherent optical frequency domain reflectometry.

    PubMed

    Ohno, Shingo; Iida, Daisuke; Toge, Kunihiro; Manabe, Tetsuya

    2016-08-22

    Long-range C-OFDR measurement of fiber Rayleigh scatter signature is described. The Rayleigh scatter signature, which is an interference pattern of backscatters from the random refractive indices in fibers, is known to be applicable to fiber identification and temperature or strain sensing by measuring its repeatability and its spectral shift. However, these applications have not been realized at ranges beyond the laser coherence length since laser phase noise degrades its repeatability. This paper proposes and demonstrates a method for analyzing the optical power spectrum of local Rayleigh backscatter to overcome the limitation imposed by laser phase noise. The measurable range and spatial performance are also investigated experimentally with respect to the remaining phase noise and noise reduction by signal averaging with the proposed method. The feasibility of Rayleigh scatter signature measurement for long-range applications is confirmed.

  5. Anomalous Rayleigh scattering with dilute concentrations of elements of biological importance

    NASA Astrophysics Data System (ADS)

    Hugtenburg, Richard P.; Bradley, David A.

    2004-01-01

    The anomalous scattering factor (ASF) correction to the relativistic form-factor approximation for Rayleigh scattering is examined in support of its utilization in radiographic imaging. ASF corrected total cross-section data have been generated for a low resolution grid for the Monte Carlo code EGS4 for the biologically important elements, K, Ca, Mn, Fe, Cu and Zn. Points in the fixed energy grid used by EGS4 as well as 8 other points in the vicinity of the K-edge have been chosen to achieve an uncertainty in the ASF component of 20% according to the Thomas-Reiche-Kuhn sum rule and an energy resolution of 20 eV. Such data is useful for analysis of imaging with a quasi-monoenergetic source. Corrections to the sampled distribution of outgoing photons, due to ASF, are given and new total cross-section data including that of the photoelectric effect have been computed using the Slater exchange self-consistent potential with the Latter tail. A measurement of Rayleigh scattering in a dilute aqueous solution of manganese (II) was performed, this system enabling determination of the absolute cross-section, although background subtraction was necessary to remove K β fluorescence and resonant Raman scattering occurring within several 100 eV of the edge. Measurements confirm the presence of below edge bound-bound structure and variation in the structure due to the ionic state that are not currently included in tabulations.

  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. Methods to improve pressure, temperature and velocity accuracies of filtered Rayleigh scattering measurements in gaseous flows

    NASA Astrophysics Data System (ADS)

    Doll, Ulrich; Burow, Eike; Stockhausen, Guido; Willert, Christian

    2016-12-01

    Frequency scanning filtered Rayleigh scattering is able to simultaneously provide time-averaged measurements of pressure, temperature and velocity in gaseous flows. By extending the underlying mathematical model, a robust alternative to existing approaches is introduced. Present and proposed model functions are then characterized during a detailed uncertainty analysis. Deviations between the analytical solution of a jet flow experiment and measured results could be related to laser-induced background radiation as well as the Rayleigh scattering’s spectral distribution. In applying a background correction method and by replacing the standard lineshape model by an empirical formulation, detrimental effects on pressure, temperature and velocity accuracies could be reduced below 15 hPa, 2.5 K and 2.7 m s-1.

  8. Polarization of Rayleigh scattered Lyα in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Chang, Seok-Jun; Lee, Hee-Won; Yang, Yujin

    2017-02-01

    The unification scheme of active galactic nuclei invokes an optically thick molecular torus component hiding the broad emission line region. Assuming the presence of a thick neutral component in the molecular torus characterized by a H I column density >1022 cm-2, we propose that far-UV radiation around Lyα can be significantly polarized through Rayleigh scattering. Adopting a Monte Carlo technique, we compute polarization of Rayleigh scattered radiation near Lyα in a thick neutral region in the shape of a slab and a cylindrical shell. It is found that radiation near Lyα Rayleigh reflected from a very thick slab can be significantly polarized in a fairly large range of wavelength Δλ ˜ 50 Å exhibiting a flux profile similar to the incident one. Rayleigh transmitted radiation in a slab is characterized by the central dip with a complicated polarization behaviour. The optically thick part near Lyα centre is polarized in the direction perpendicular to the slab normal, which is in contrast to weakly polarized wing parts in the direction parallel to the slab normal. A similar polarization flip phenomenon is also found in the case of a tall cylindrical shell, in which the spatial diffusion along the vertical direction near the inner cylinder wall for core photons leads to a tendency of the electric field aligned to the direction perpendicular to the vertical axis. Observational implications are briefly discussed including spectropolarimetry of the quasar PG 1630+377 by Koratkar et al. in 1990 where Lyα is strongly polarized with no other emission lines polarized.

  9. Light Scattering in Exoplanet Transits

    NASA Astrophysics Data System (ADS)

    Robinson, Tyler D.; Fortney, Jonathan J.

    2016-10-01

    Transit spectroscopy is currently the leading technique for studying exoplanet atmospheric composition, and has led to the detection of molecular species, clouds, and/or hazes for numerous worlds outside the Solar System. The field of exoplanet transit spectroscopy will be revolutionized with the anticipated launch of NASA's James Webb Space Telescope (JWST) in 2018. Over the course of the design five year mission for JWST, the observatory is expected to provide in-depth observations of many tens of transiting exoplanets, including some worlds in the poorly understood 2-4 Earth-mass regime. As the quality of transit spectrum observations continues to improve, so should models of exoplanet transits. Thus, certain processes initially thought to be of second-order importance should be revisited and possibly added to modeling tools. For example, atmospheric refraction, which was commonly omitted from early transit spectrum models, has recently been shown to be of critical importance in some terrestrial exoplanet transits. Beyond refraction, another process that has seen little study with regards to exoplanet transits is light multiple scattering. In most cases, scattering opacity in exoplanet transits has been treated as equivalent to absorption opacity. However, this equivalence cannot always hold, such as in the case of a strongly forward scattering, weakly absorbing aerosol. In this presentation, we outline a theory of exoplanet transit spectroscopy that spans the geometric limit (used in most modern models) to a fully multiple scattering approach. We discuss a new technique for improving model efficiency that effectively separates photon paths, which tend to vary slowly in wavelength, from photon absorption, which can vary rapidly in wavelength. Using this newly developed approach, we explore situations where cloud or haze scattering may be important to JWST observations of gas giants, and comment on the conditions necessary for scattering to become a major

  10. Comparison of the GHSSmooth and the Rayleigh-Rice surface scatter theories

    NASA Astrophysics Data System (ADS)

    Harvey, James E.; Pfisterer, Richard N.

    2016-09-01

    The scalar-based GHSSmooth surface scatter theory results in an expression for the BRDF in terms of the surface PSD that is very similar to that provided by the rigorous Rayleigh-Rice (RR) vector perturbation theory. However it contains correction factors for two extreme situations not shared by the RR theory: (i) large incident or scattered angles that result in some portion of the scattered radiance distribution falling outside of the unit circle in direction cosine space, and (ii) the situation where the relevant rms surface roughness, σrel, is less than the total intrinsic rms roughness of the scattering surface. Also, the RR obliquity factor has been discovered to be an approximation of the more general GHSSmooth obliquity factor due to a little-known (or long-forgotten) implicit assumption in the RR theory that the surface autocovariance length is longer than the wavelength of the scattered radiation. This assumption allowed retaining only quadratic terms and lower in the series expansion for the cosine function, and results in reducing the validity of RR predictions for scattering angles greater than 60°. This inaccurate obliquity factor in the RR theory is also the cause of a complementary unrealistic "hook" at the high spatial frequency end of the predicted surface PSD when performing the inverse scattering problem. Furthermore, if we empirically substitute the polarization reflectance, Q, from the RR expression for the scalar reflectance, R, in the GHSSmooth expression, it inherits all of the polarization capabilities of the rigorous RR vector perturbation theory.

  11. 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.

  12. NIR femtosecond laser induced hyper-Rayleigh scattering and luminescence from silver nanoprisms.

    PubMed

    Jain, Beena; Srivastava, Arvind Kumar; Uppal, Abha; Gupta, Pradeep Kumar; Das, Kaustuv

    2010-09-01

    The nonlinear response of silver nanoprisms (edge length 40 +/- 5 nm and thickness 4.5 +/- 0.5 nm) was studied by exciting with NIR femtosecond pulses (780-880 nm). These nanostructures were observed to generate hyper-Rayleigh scattering (HRS) and broadband luminescence. While HRS showed the expected second order power dependence, the luminescence was observed to follow a third order excitation power dependence. Both HRS and luminescence were observed to be dipolar in nature. The first hyperpolarizability of the nanoprisms was found to be an order of magnitude higher than approximately 15 nm sized nanospheres.

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

    PubMed

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

    2011-01-15

    We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber. Twenty-two lasing lines with spacing of ~100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt 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.

  14. Brillouin-Raman comb fiber laser with cooperative Rayleigh scattering in a linear cavity.

    PubMed

    Zamzuri, A K; Md Ali, M I; Ahmad, A; Mohamad, R; Mahdi, M A

    2006-04-01

    We demonstrate a multiple-wavelength Brillouin comb laser with cooperative Rayleigh scattering that uses Raman amplification in dispersion-compensating fiber. The laser resonator is a linear cavity formed by reflector at each end of the dispersion-compensating fiber to improve the reflectivity of the Brillouin Stokes comb. Multiple Brillouin Stokes generation has been improved in terms of optical signal-to-noise ratio and power-level fluctuation between neighboring channels. Furthermore, the linewidth of the Brillouin Stokes is uniform within the laser output bandwidth.

  15. Laser light scattering in diagnostics of widespread diseases

    NASA Astrophysics Data System (ADS)

    Petrova, Galina P.; Petrusevich, Yurii M.; Alexeev, Sergei G.; Ivanov, Andrei V.

    2002-08-01

    The multiparametric physical method for diagnosing of widespread diseases including oncological disease based on Rayleigh light scattering is proposed. There was studied simultaneously dynamic and static parameters of blood plasma proteins. This method is the product of extensive research conducted on a molecular level on the indicative fields of the human body such as blood serum or lymph. Comprehensive measurements at molecular level and determinations of parameters related to these fluids, especially blood serum, have revealed significant differences in the values of certain parameters in patients with oncological diseases and for healthy individuals.

  16. 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

  17. Single-scattering parabolic equation solutions for elastic media propagation, including Rayleigh waves.

    PubMed

    Metzler, Adam M; Siegmann, William L; Collins, Michael D

    2012-02-01

    The parabolic equation method with a single-scattering correction allows for accurate modeling of range-dependent environments in elastic layered media. For problems with large contrasts, accuracy and efficiency are gained by subdividing vertical interfaces into a series of two or more single-scattering problems. This approach generates several computational parameters, such as the number of interface slices, an iteration convergence parameter τ, and the number of iterations n for convergence. Using a narrow-angle approximation, the choices of n=1 and τ=2 give accurate solutions. Analogous results from the narrow-angle approximation extend to environments with larger variations when slices are used as needed at vertical interfaces. The approach is applied to a generic ocean waveguide that includes the generation of a Rayleigh interface wave. Results are presented in both frequency and time domains.

  18. 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.

  19. Structure of the pyridine-chloranil complex in solution: a surprise from depolarized hyper-Rayleigh scattering measurements.

    PubMed

    Pandey, Ravindra; Mukhopadhyay, S; Ramasesha, S; Das, Puspendu K

    2011-12-01

    In this article, we report the structure of a 1:1 charge transfer complex between pyridine (PYR) and chloranil (CHL) in solution (CHCl(3)) from the measurement of hyperpolarizability (β(HRS)) and linear and circular depolarization ratios, D and D', respectively, by the hyper-Rayleigh scattering technique and state-of-the-art quantum chemical calculations. Using linearly (electric field vector along X) and circularly polarized incident light, respectively, we have measured two macroscopic depolarization ratios D = I(X,X)(2ω)/I(X,Z)(2ω) and D' = I(X,C)(2ω)/I(Z,C)(2ω) in the laboratory fixed XYZ frame by detecting the second harmonic (SH) scattered light in a polarization resolved fashion. The stabilization energy and the optical gap calculated through the MP2/cc-pVDZ method using Gaussian09 were not significantly different to distinguish between the cofacial and T-shape structures. Only when the experimentally obtained β(HRS) and the depolarization ratios, D and D', were matched with the theoretically computed values from single and double configuration interaction (SDCI) calculations performed using the ZINDO-SCRF technique, we concluded that the room temperature equilibrium structure of the complex is cofacial. This is in sharp contrast to an earlier theoretical prediction of the T-shape structure of the complex.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Many-electron effects on x-ray Rayleigh scattering by highly charged He-like ions

    NASA Astrophysics Data System (ADS)

    Volotka, A. V.; Yerokhin, V. A.; Surzhykov, A.; Stöhlker, Th.; Fritzsche, S.

    2016-02-01

    The Rayleigh scattering of x rays by many-electron highly charged ions is studied theoretically. The many-electron perturbation theory, based on a rigorous quantum electrodynamics approach, is developed and implemented for the case of the elastic scattering of (high-energetic) photons by heliumlike ions. Using this elaborate approach, we here investigate the many-electron effects beyond the independent-particle approximation (IPA) as conventionally employed for describing the Rayleigh scattering. The total and angle-differential cross sections are evaluated for the x-ray scattering by heliumlike Ni26 +,Xe52 +, and Au77 + ions in their ground state. The obtained results show that, for high-energetic photons, the effects beyond the IPA do not exceed 2% for the scattering by a closed K shell.

  5. Interaction of proteins with aluminum(III)-chlorophosphonazo III by resonance Rayleigh scattering method.

    PubMed

    Cui, Zhi-Ping; Liu, Shao-Pu; Liu, Zhong-Fang; Zheng, Hu-Zhi; Hu, Xiao-Li; Xue, Jia-Xing; Tian, Jing

    2014-11-01

    In weak acid medium, aluminum(III) can react with chlorophosphonazo III [CPA(III), H(8)L] to form a 1:1 coordination anion [Al(OH)(H(4)L)](2-). At the same time, proteins such as bovine serum albumin (BSA), lysozyme (Lyso) and human serum albumin (HSA) existed as large cations with positive charges, which further combined with [Al(OH)(H(4)L)](2-) to form a 1:4 chelate. This resulted in significant enhancement of resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS). In this study, we investigated the interaction between [Al(OH)(H(4)L)](2-) and proteins, optimization of the reaction conditions and the spectral characteristics of RRS, SOS and FDS. The maximum RRS wavelengths of different protein systems were located at 357-370 nm. The maximum SOS and FDS wavelengths were located at 546 and 389 nm, respectively. The scattering intensities (ΔI) of the three methods were proportional to the concentration of the proteins, within certain ranges, and the detection limits of the most sensitive RRS method were 2.6-9.3 ng/mL. Moreover, the chelate reaction mechanism or the reasons for the enhancement of RRS were discussed through absorption spectra, fluorescence spectra and circular dichroism (CD) spectra.

  6. 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.

  7. 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.

  8. 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.

  9. 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

    2013-12-02

    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.

  10. Scattering of Rayleigh-Lamb waves by a surface breaking crack in an elastic plate.

    PubMed

    Flores-López, Miguel A; Gregory, R Douglas

    2006-04-01

    This work studies the problem of scattering of Rayleigh-Lamb waves by a thin surface-breaking crack. The problem is solved by the projection method, which exploits some orthogonality relations deduced from the reciprocal theorem. Numerical results obtained by the projection method are compared with the results obtained using a finite element method reported by other authors for the case of a flat crack, finding good agreement. From the numerical results it is observed that, as the wave number of the incident wave, so for instance, is smaller, the reflected and transmitted energy corresponding to the converted mode, A0 in this case, are almost equal to each other. An explanation for this result is given, based on the asymptotic nature of the modes S0 and A0 for small wave numbers.

  11. 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.

  12. 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.

  13. Multi-kHz temperature imaging in turbulent non-premixed flames using planar Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Patton, R. A.; Gabet, K. N.; Jiang, N.; Lempert, W. R.; Sutton, J. A.

    2012-08-01

    In this manuscript, we describe the development of two-dimensional, high-repetition-rate (10-kHz) Rayleigh scattering imaging as applied to turbulent combustion environments. In particular, we report what we believe to be the first sets of high-speed planar Rayleigh scattering images in turbulent non-premixed flames, yielding temporally correlated image sequences of the instantaneous temperature field. Sample results are presented for the well-characterized DLR flames A and B (CH4/H2/N2) at Reynolds numbers of 15,200 and 22,800 at various axial positions downstream of the jet exit. The measurements are facilitated by the use of a user-calibrated, intensified, high-resolution CMOS camera in conjunction with a unique high-energy, high-repetition-rate pulse-burst laser system (PBLS) at Ohio State University, which yields output energies up to 200 mJ/pulse at 532 nm with 100-μs laser pulse spacing. The spatial and temporal resolution of the imaging system and acquired images are compared to the finest spatial and temporal scales expected within the turbulent flames. One of the most important features of the PBLS is the ability to readily change the pulse-to-pulse spacing as the required temporal resolution necessitates it. The quality and accuracy of the high-speed temperature imaging results are assessed by comparing derived statistics (mean and standard deviation) to that of previously reported point-based reference data acquired at Sandia National Laboratories and available within the TNF workshop. Good agreement between the two data sets is obtained providing an initial indication of quantitative nature of the planar, kHz-rate temperature imaging results.

  14. POLARIZED PARTIAL FREQUENCY REDISTRIBUTION IN SUBORDINATE LINES. II. SOLUTION OF THE TRANSFER EQUATION WITH RAYLEIGH SCATTERING

    SciTech Connect

    Nagendra, K. N.; Sampoorna, M. E-mail: sampoorna@iiap.res.in

    2012-09-20

    It is quite common in line formation theory to treat scattering in subordinate lines under the assumption of complete frequency redistribution (CRD). The partial frequency redistribution (PRD) in subordinate lines cannot always be approximated by CRD, especially when the polarization state of the line radiation is taken into account. Here we investigate the PRD effects in subordinate lines including scattering polarization. The line formation is described by a polarized non-LTE line transfer equation based on a two-level atom model. We use the recently derived subordinate line redistribution matrix. We devise polarized approximate lambda iteration methods to solve the concerned transfer problem. The linear polarization profiles of subordinate lines formed in non-magnetic (Rayleigh) scattering atmospheres are discussed. We consider one-dimensional isothermal planar model atmospheres. We show that in the polarized line transfer calculations of subordinate lines, PRD plays as important of a role as it does in the case of resonance lines. We also study the effect of collisions on linear polarization profiles of subordinate lines.

  15. 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.

  16. 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.

  17. Light scattering by adjacent red blood cells: a mathematical model

    NASA Astrophysics Data System (ADS)

    Uzunoglou, Nikolaos K.; Stamatakos, Georgios; Koutsouris, Dimitrios; Yova-Loukas, Dido M.

    1995-01-01

    Simple approximate scattering theories such as the Rayleigh-Gans theory are not generally applicable to the case of light scattering by red blood cell (RBC) aggregates, including thrombus. This is mainly due to the extremely short distance separating erythrocytes in the aggregates (of the order of 25 nm) as well as to the substantial size of the aggregates. Therefore, in this paper a new mathematical model predicting the electromagnetic field produced by the scattering of a plane electromagnetic wave by a system of two adjacent RBCs is presented. Each RBC is modeled as a homogeneous dielectric ellipsoid of complex index of refraction surrounded by transparent plasma. The relative position and orientation of the ellipsoids are arbitrary. Scattering is formulated in terms of an integral equation which, however, contains two singular kernels. The singular equation is transformed into a pair of nonsingular integral equations for the Fourier transform of the internal field of each RBC. The latter equations are solved by reducing them by quadrature into a matrix equation. The resulting solutions are used to estimate the scattering amplitude. Convergence aspects concerning the numerical calculation of the matrix elements originating from the interaction between the RBCs are also presented.

  18. Designs and Reliability Evaluations of a Scattered Light Measurement System

    NASA Astrophysics Data System (ADS)

    Lee, Kang-Min

    The purpose of my work was to develop an in-plane stray light measurement system having the advantage of being easily applicable in both motion control and optical configurations. First of all, mechanical designs were conducted based on both 3D modeling and structural analysis through a finite element method (FEM). Optical configurations for both the incident source and the detector were designed to achieve minimum observed source convergence angle of the system. The control panel and micro stepping system were programmed for automated measurement. Finally, the designed system was calibrated and aligned. In order to evaluate the system reliability for scatter measurements from various surface conditions, a total of 9 samples were used. Scattering analysis for bidirectional scatter distribution functions of the samples were conducted: rough surface, smooth surface and small particles. ABg model, Rayleigh-Rice theory and Generalized Harvey-Shack theory were used to verify the scatter measurements. The results indicate that the designed system was appropriately developed for measuring scattering phenomena by rough surface, smooth surface and small particles.

  19. Directional light scattering from individual Au nanocup

    NASA Astrophysics Data System (ADS)

    Bai, Jinjun; Li, Yong; Zhao, Bo

    2017-03-01

    We investigate the optical scattering properties of gold nanocup with different orientation and fractional height by full vector finite element method. All of the scattering cross section, the distribution of electric field intensity, and the ability of directional light scattering are simulated, respectively. It is demonstrated that the scattering cross section of Au nanocup is a superposition of scattering spectrum of a transverse mode and an axial mode. The wavelength and the intensity of the maximum value of the scattering cross section increase initially then reduce with the fractional height increasing for transverse mode, while they increase monotonously with the fractional height increasing for axial mode. Furthermore, the calculation results show that the ability of redirecting incident light of Au nanocup mainly depends on the transverse mode. And the deflected angle of scattering increases with the fractional height of Au nanocup decreasing. These results indicate that Au nanocup has a promising application in the planar plasmon devices.

  20. 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.

  1. Resonance Rayleigh scattering technique for simple and sensitive analysis of tannic acid with carbon dots

    NASA Astrophysics Data System (ADS)

    Shi, Ying; Yang, Liu; Zhu, Jinghui; Yang, Jidong; Liu, Shaopu; Qiao, Man; Duan, Ruilin; Hu, Xiaoli

    2017-02-01

    Carbon dots (CDs) are raising a substantial amount of attention owing to their many unique and novel physicochemical properties. Herein one-pot synthesized CDs, to the best of our knowledge, were first served as the robust nanoprobe for detection tannic acid (TA) based on resonance Rayleigh scattering technique. The as-prepared CDs can combine with TA via hydrogen bond, resulting in remarkable enhancement of scattering signal with no changes in the fluorescence of CDs. Therefore, a novel protocol for TA determination was established and this strategy allowed quantitative detection of TA in the linear range of 0.2-10.0 μmol L- 1 with an excellent detection limit of 9.0 nmol L- 1. Moreover, the CDs based nanoprobe can be applied to the determination of TA in water sample with satisfactory results. Our study can potentially influence our current views on CDs and particularly impressive and offers new insights into application of CDs beyond the traditional understanding of CDs.

  2. Resonance Rayleigh scattering technique for simple and sensitive analysis of tannic acid with carbon dots.

    PubMed

    Shi, Ying; Yang, Liu; Zhu, Jinghui; Yang, Jidong; Liu, Shaopu; Qiao, Man; Duan, Ruilin; Hu, Xiaoli

    2017-02-15

    Carbon dots (CDs) are raising a substantial amount of attention owing to their many unique and novel physicochemical properties. Herein one-pot synthesized CDs, to the best of our knowledge, were first served as the robust nanoprobe for detection tannic acid (TA) based on resonance Rayleigh scattering technique. The as-prepared CDs can combine with TA via hydrogen bond, resulting in remarkable enhancement of scattering signal with no changes in the fluorescence of CDs. Therefore, a novel protocol for TA determination was established and this strategy allowed quantitative detection of TA in the linear range of 0.2-10.0μmolL(-1) with an excellent detection limit of 9.0nmolL(-1). Moreover, the CDs based nanoprobe can be applied to the determination of TA in water sample with satisfactory results. Our study can potentially influence our current views on CDs and particularly impressive and offers new insights into application of CDs beyond the traditional understanding of CDs.

  3. 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.

  4. 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.

  5. Semi-imaging light pipe for collecting weakly scattered light

    NASA Astrophysics Data System (ADS)

    Hopkins, George W.; Simons, Tad D.

    1998-09-01

    A simple reflective light pipe, formed from a cylindrical tube with an external reflective coating and a small central aperture, can be a highly efficient optical element for collecting light from molecular scattering processes along the path of a laser beam. When the laser beam is co-linear with the axis of the light pipe, scattered light from any location along the interaction region (near the pipe axis) re-images repeatedly to another location along the axis of the pipe. This semi-imaging property of the light pipe permits a large fraction of the total scattered light to re- image along the entire length of the interaction region. If one observes through the small central aperture, scattered light from the single segment of the laser beam in view appears to come from all the locations along the interaction length, as well as from the single segment. In this manner, one can have the advantage of collecting scattered light from a small segment (and thus onto a small detector), while observing an effective interaction length that is many times longer than the segment. Measurements from practical light pipes confirm effective gains of about 10X with light pipes a few centimeters long (Effective gain is defined as the ratio of light collected with the light pipe divided by the light collected from a direct image of the beam using the collection optics).

  6. Multiple-Rayleigh-scatterer-induced mode splitting in a high-Q whispering-gallery-mode microresonator

    SciTech Connect

    Yi Xu; Xiao Yunfeng; Liu Yongchun; Li Beibei; Chen Youling; Li Yan; Gong Qihuang

    2011-02-15

    We theoretically investigate the mode-splitting phenomenon in a high-Q whispering-gallery-mode (WGM) microresonator coupled to multiple subwavelength Rayleigh scatterers. It is shown that the phase factors of the WGMs play the central role in such a system. Unlike the single-scatterer case, these phase factors in a multiscatterer system significantly influence both the modal coupling strength and the scattering-induced loss of a pair of counterpropagating WGMs. We scrutinize the condition for observing the splitting of transmission spectra. The mechanism can be used for highly sensitive biosensing, and the size of nanoparticles that can be detected is extended down to tens of nanometers.

  7. 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.

  8. Structured light, transmission, and scattering

    NASA Astrophysics Data System (ADS)

    Andrews, David L.

    2011-03-01

    Numerous theoretical and experimental studies have established the principle that beams conveying orbital angular momentum offer a rich scope for information transfer. However, it is not clear how far it is practicable to operate such a concept at the single-photon level - especially when such a beam propagates through a system in which scattering can occur. In cases where scattering leads to photon deflection, it produces losses; however in terms of the retention of information content, there should be more concern over forward scattering. Based on a quantum electrodynamical formulation of theory, this paper aims to frame and resolve the key issues. A quantum amplitude is constructed for the representation of single and multiple scattering events in the propagation an individual photon, from a suitably structured beam. The analysis identifies potential limitations of principle, undermining complete fidelity of quantum information transmission.

  9. 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

  10. Comparison of Coincident Rayleigh-Scatter and Sodium Resonance Lidar Temperature Measurements from the Mesosphere-Lower-Thermosphere Region

    NASA Astrophysics Data System (ADS)

    Sox, L.; Wickwar, V. B.; Yuan, T.; Criddle, N.

    2015-12-01

    There are relatively few instruments that have the capabilities to make near continuous measurements of the mesosphere-lower-thermosphere (MLT) region. Rayleigh scatter and resonance lidars, particularly sodium resonance lidar, have been the two dominant ground-based techniques for acquiring mesosphere and MLT vertical temperature profiles, respectively, for more than two decades. With these measurements, the dynamics (gravity waves, tides) and long-term temperature trends (upper atmosphere cooling) of the MLT region can be studied. The Utah State University (USU; 41.7º N, 111.8º W) campus hosts a unique upper atmospheric observatory which houses both a high-power, large-aperture Rayleigh lidar and a sodium resonance Doppler lidar. For the first time, we will present coordinated, night-time averaged temperatures, overlapping in observational range (80-110 km), from the two lidars. This overlap has been achieved through the relocation of the sodium lidar from Colorado State University to USU's campus and through upgrades to the existing USU Rayleigh lidar which elevated its observational range from 45-90 km to 70-115 km. The comparison of the two sets of temperature measurements is important because the two lidar techniques derive temperature profiles using different scattering processes and analysis methods. Furthermore, previous climatological comparisons, between Rayleigh and sodium lidar, [Argall and Sica, 2007] have suggested that significant temperature differences can occur. This comparison aims to explore possible temperature effects from the differences in the two measurement techniques.

  11. Differential Light Scattering from Spherical Mammalian Cells

    PubMed Central

    Brunsting, Albert; Mullaney, Paul F.

    1974-01-01

    The differential scattered light intensity patterns of spherical mammalian cells were measured with a new photometer which uses high-speed film as the light detector. The scattering objects, interphase and mitotic Chinese hamster ovary cells and HeLa cells, were modeled as (a) a coated sphere, accounting for nucleus and cytoplasm, and (b) a homogeneous sphere when no cellular nucleus was present. The refractive indices and size distribution of the cells were measured for an accurate comparison of the theoretical model with the light-scattering measurements. The light scattered beyond the forward direction is found to contain information about internal cellular morphology, provided the size distribution of the cells is not too broad. ImagesFIGURE 1 PMID:4134589

  12. 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.

  13. The Amsterdam-Granada Light Scattering Database

    NASA Astrophysics Data System (ADS)

    Muñoz, O.; Moreno, F.; Guirado, D.; Dabrowska, D. D.; Volten, H.; Hovenier, J. W.

    2012-02-01

    The Amsterdam Light Scattering Database proved to be a very successful way of promoting the use of the data obtained with the Amsterdam Light Scattering apparatus at optical wavelengths. Many different research groups around the world made use of the experimental data. After the closing down of the Dutch scattering apparatus, a modernized and improved descendant, the IAA Cosmic Dust Laboratory (CoDuLab), has been constructed at the Instituto de Astrofísica de Andalucía (IAA) in Granada, Spain. The first results of this instrument for water droplets and for two samples of clay particles have been published. We would now like to make these data also available to the community in digital form by introducing a new light scattering database, the Amsterdam-Granada Light Scattering Database (www.iaa.es/scattering). By combining the data from the two instruments in one database we ensure the continued availability of the old data, and we prevent fragmentation of important data over different databases. In this paper we present the Amsterdam-Granada Light Scattering Database.

  14. 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.

  15. 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.

  16. Semi-classical dynamics of superradiant Rayleigh scattering in a Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Müller, J. H.; Witthaut, D.; le Targat, R.; Arlt, J. J.; Polzik, E. S.; Hilliard, A. J.

    2016-10-01

    Due to its coherence properties and high optical depth, a Bose-Einstein condensate [BEC] provides an ideal setting to investigate collective atom-light interactions. Superradiant light scattering [SLS] in a BEC is a fascinating example of such an interaction. It is an analogous process to Dicke superradiance, in which an electronically inverted sample decays collectively, leading to the emission of one or more light pulses in a well-defined direction. Through time-resolved measurements of the superradiant light pulses emitted by an end-pumped BEC, we study the close connection of SLS with Dicke superradiance. A 1D model of the system yields good agreement with the experimental data and shows that the dynamics result from the structures that build up in the light and matter-wave fields along the BEC. This paves the way for exploiting the atom-photon correlations generated by the superradiance.

  17. 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%.

  18. 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.

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

    PubMed

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

    2016-09-05

    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.

  20. Gold Nanorod Based Selective Identification of Escherichia coli Bacteria Using Two-Photon Rayleigh Scattering Spectroscopy.

    PubMed

    Singh, Anant K; Senapati, Dulal; Wang, Shuguang; Griffin, Jelani; Neely, Adria; Candice, Perry; Naylor, Khaleah M; Varisli, Birsen; Kalluri, Jhansi Rani; Ray, Paresh Chandra

    2009-07-28

    The presence of E. coli in foodstuffs and drinking water is a chronic worldwide problem. The worldwide food production industry is worth about U.S. $578 billion, and the demand for biosensors to detect pathogens and pollutants in foodstuffs is growing day by day. Driven by the need, we report for the first time that two-photon Rayleigh scattering (TPRS) properties of gold nanorods can be used for rapid, highly sensitive and selective detection of Escherichia coli bacteria from aqueous solution, without any amplification or enrichment in 50 colony forming units (cfu)/mL level with excellent discrimination against any other bacteria. TPRS intensity increases 40 times when anti- E. coli antibody-conjugated nanorods were mixed with various concentrations of Escherichia coli O157:H7 bacterium. The mechanism of TPRS intensity change has been discussed. This bionanotechnology assay could be adapted in studies using antibodies specific for various bacterial pathogens for the detection of a wide variety of bacterial pathogens used as bioterrorism agents in food, clinical samples, and environmental samples.

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

    NASA Astrophysics Data System (ADS)

    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 3.5 μg/mL, and the limit of detection (LOD) was 6.94 ng/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.

  2. 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.

  3. Spectrally- and polarization-resolved hyper-Rayleigh scattering measurements with polarization-insensitive detection

    NASA Astrophysics Data System (ADS)

    Němec, P.; Pásztor, F.; Brajer, M.; Němec, I.

    2017-04-01

    Determination of the molecular first hyperpolarizability by hyper-Rayleigh scattering (HRS) is usually significantly complicated by a presence of the multiphoton excited fluorescence which has to be separated from HRS to obtain a meaningful values of the hyperpolarizability. We show, by performing a spectrally-resolved measurement, that the intensity and spectral shape of the fluorescence can depend strongly on the fundamental laser wavelength. Consequently, a properly selected excitation wavelength can significantly simplify the process of separation of HRS from the detected signal. We tested the developed experimental setup with a polarization-insensitive detection by measuring HRS generated in water and in aqueous solutions of 2-aminopyrimidine (AMP) and its monocation (HAMP). The effective hyperpolarizability of AMP and HAMP was measured experimentally and compared with that obtained by quantum chemical calculations. The polarization-resolved HRS measurement was performed for AMP and the experimentally obtained depolarization ratio agrees well with that predicted theoretically, which confirms that routine density functional theory computations of static hyperpolarizability tensor components can be considered as a sufficient approach suitable for non-interacting molecules dissolved in water.

  4. 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.

  5. Extinction paradox and actual power scattered in light beam scattering: a two-dimensional study.

    PubMed

    Lai, H M; Wong, W Y; Wong, W H

    2004-12-01

    The extinction paradox is examined by applying partial-wave analysis to a two-dimensional light beam interacting with a long transverse cylinder without absorption, assuming always short wavelengths. We show that the (conventional) power scattered, Psca, except for a very narrow beam hitting a transparent cylinder on axis, is always double the power directly intercepted by the scatterer, Pitc, including a zero result for Psca when the incident beam is basically off the material surface. This contradicts the interpretation that attributes one half of Psca to edge diffraction by the scatterer. Furthermore, we identify the shadow-forming wave (SFW) from the partial-wave sum in the forward direction and show that the actual power scattered or, equivalently, the power depleted from the incident beam is equal to one unit of Pitc for a narrow beam, gets larger for a broader beam, and approaches 2Pitc for a very broad beam. The larger value in the latter cases is due to the extent of divergence of the SFW beam out of the incident beam at distances well beyond the Rayleigh range.

  6. 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.

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

    PubMed

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

    2015-02-05

    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.

  8. Expressive Single Scattering for Light Shaft Stylization.

    PubMed

    Kol, Timothy R; Klehm, Oliver; Seidel, Hans-Peter; Eisemann, Elmar

    2016-04-14

    Light scattering in participating media is a natural phenomenon that is increasingly featured in movies and games, as it is visually pleasing and lends realism to a scene. In art, it may further be used to express a certain mood or emphasize objects. Here, artists often rely on stylization when creating scattering effects, not only because of the complexity of physically correct scattering, but also to increase expressiveness. Little research, however, focuses on artistically influencing the simulation of the scattering process in a virtual 3D scene. We propose novel stylization techniques, enabling artists to change the appearance of single scattering effects such as light shafts. Users can add, remove, or enhance light shafts using occluder manipulation. The colors of the light shafts can be stylized and animated using easily modifiable transfer functions. Alternatively, our system can optimize a light map given a simple user input for a number of desired views in the 3D world. Finally, we enable artists to control the heterogeneity of the underlying medium. Our stylized scattering solution is easy to use and compatible with standard rendering pipelines. It works for animated scenes and can be executed in real time to provide the artist with quick feedback.

  9. Hadronic light-by-light scattering in muonium hyperfine splitting

    SciTech Connect

    Karshenboim, S. G.; Shelyuto, V. A.; Vainshtein, A. I.

    2008-09-15

    We consider an impact of hadronic light-by-light scattering on the muonium hyperfine structure. A shift of the hyperfine interval {delta}{nu}(Mu){sub HLBL} is calculated with the light-by-light scattering approximated by the exchange of pseudoscalar and pseudovector mesons. Constraints from the operator product expansion in QCD are used to fix parameters of the model similar to the one used earlier for the hadronic light-by-light scattering in calculations of the muon anomalous magnetic moment. The pseudovector exchange is dominant in the resulting shift, {delta}{nu}(Mu){sub HLBL}=-0.0065(10) Hz. Although the effect is tiny it is useful in understanding the level of hadronic uncertainties.

  10. Shear Brillouin light scattering microscope

    PubMed Central

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

    2016-01-01

    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

  11. Effect of laser-radiation polarization on the nonlinear scattering of light in nanodiamond suspensions

    NASA Astrophysics Data System (ADS)

    Mikheev, G. M.; Vanyukov, V. V.; Mogileva, T. N.; Puzyr', A. P.; Bondar', V. S.; Svirko, Yu. P.

    2014-07-01

    The effect of laser radiation polarization on the nonlinear scattering of light in aqueous suspensions of detonation nanodiamonds (DNDs) in a regime of optical power limiting (OPL) has been studied. It is established that the nonlinear transmission coefficient of DND suspension in the OPL regime in a field of nanosecond laser pulses with a wavelength of 532 nm is independent of the polarization of incident radiation. The nonlinear scattering of light observed at an angle of 90° in the plane perpendicular to the plane of polarization of the incident radiation depends on the polarization angle in accordance with a trigonometric law. It is shown that the ratio of the signals of scattered radiation for the vertical and horizontal polarizations exhibits nonmonotonic dependence on the laser-beam power density. The results are explained by the Rayleigh-Mie scattering and a change in the size of scattering centers as a result of the effect of a laser upon the DND suspension.

  12. 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.

  13. 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.

  14. 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…

  15. 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.

  16. 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.

  17. Scattered light mapping of protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Stolker, T.; Dominik, C.; Min, M.; Garufi, A.; Mulders, G. D.; Avenhaus, H.

    2016-12-01

    Context. High-contrast scattered light observations have revealed the surface morphology of several dozen protoplanetary disks at optical and near-infrared wavelengths. Inclined disks offer the opportunity to measure part of the phase function of the dust grains that reside in the disk surface which is essential for our understanding of protoplanetary dust properties and the early stages of planet formation. Aims: We aim to construct a method which takes into account how the flaring shape of the scattering surface of an optically thick protoplanetary disk projects onto the image plane of the observer. This allows us to map physical quantities (e.g., scattering radius and scattering angle) onto scattered light images and retrieve stellar irradiation corrected images (r2-scaled) and dust phase functions. Methods: The scattered light mapping method projects a power law shaped disk surface onto the detector plane after which the observed scattered light image is interpolated backward onto the disk surface. We apply the method on archival polarized intensity images of the protoplanetary disk around HD 100546 that were obtained with VLT/SPHERE in the R' band and VLT/NACO in the H and Ks bands. Results: The brightest side of the r2-scaled R' band polarized intensity image of HD 100546 changes from the far to the near side of the disk when a flaring instead of a geometrically flat disk surface is used for the r2-scaling. The decrease in polarized surface brightness in the scattering angle range of 40°-70° is likely a result of the dust phase function and degree of polarization which peak in different scattering angle regimes. The derived phase functions show part of a forward scattering peak, which indicates that large, aggregate dust grains dominate the scattering opacity in the disk surface. Conclusions: Projection effects of a protoplanetary disk surface need to be taken into account to correctly interpret scattered light images. Applying the correct scaling for the

  18. 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)

  19. Comparison of Gas Displacement based on Thermometry in the Pulse Tube with Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Hagiwara, Yasumasa; Nara, Kenichi; Ito, Seitoku; Saito, Takamoto

    A pulse tube refrigerator has high reliability because of its simple structure. Recently the level of development activity of the pulse tube refrigerator has increased, but the quantitative understanding of the refrigeration mechanism has not fully been obtained. Therefore various explanations were proposed. The concept of virtual gas piston in particular helps us to understand the function of a phase shifter such as a buffer tank and an orifice because the virtual gas piston corresponds to a piston of a Stirling refrigerator. However it is difficult to directly measure the averaged gas displacement which corresponds to the virtual gas piston because uniform gas flow such as a gas piston does not always exist. For example, there are a jet flow from orifice and circulated flows in a pulse tube, which are predicted theoretically. In spite of these phenomena, the averaged gas displacement is very important in practical use because it can simply predict the performance from the displacement. In this report, we calculate the averaged gas displacement and mass flow through an orifice. The mass flow is calculated from the pressure change in a buffer tank. The averaged gas displacement is calculated from temperature profiles in the pulse tube and the mass flow. It is necessary to measure temperature in the pulse tube as widely as possible in order to calculate the averaged gas displacement. We apply a method using the Rayleigh Scattering the thermometry in the pulse tube. With this method, it is possible to perform 2-dimensional measurement without disturbing the gas flow. By this method, the averaged gas displacements and the temperature profiles of basic and orifice types of refrigeration were compared.

  20. 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.

  1. 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.

  2. Polarization of scattered light in biological tissue

    NASA Astrophysics Data System (ADS)

    Abubaker, Hamed M.; Tománek, Pavel

    2012-02-01

    The real-time nondestructive inspection of biological tissues begins to be one of important tools which could contribute to better human life not only in medical diagnosis but also in everyday mankind activities. A biological tissue is considered as a turbid medium in which light is scattered. Although single or multiple scattering in tissue multiple randomizes polarization states of incident light, linear, circular and elliptical polarization states in the medium are considered, and there are circumstances when appreciable degree of polarization can be observed in diffusive scattering. Our work shows that with a sufficient degree of sensitivity is possible to detect structural changes due to the aging of processed meat by using Mueller matrix polarimeter. Moreover, it demonstrated that the degree of polarization of the backscattered light is sensitive to the optical properties of specimen material and to its thickness.

  3. Polarization of scattered light in biological tissue

    NASA Astrophysics Data System (ADS)

    Abubaker, Hamed M.; Tománek, Pavel

    2011-09-01

    The real-time nondestructive inspection of biological tissues begins to be one of important tools which could contribute to better human life not only in medical diagnosis but also in everyday mankind activities. A biological tissue is considered as a turbid medium in which light is scattered. Although single or multiple scattering in tissue multiple randomizes polarization states of incident light, linear, circular and elliptical polarization states in the medium are considered, and there are circumstances when appreciable degree of polarization can be observed in diffusive scattering. Our work shows that with a sufficient degree of sensitivity is possible to detect structural changes due to the aging of processed meat by using Mueller matrix polarimeter. Moreover, it demonstrated that the degree of polarization of the backscattered light is sensitive to the optical properties of specimen material and to its thickness.

  4. Pushing the upper limit of Rayleigh-scatter Temperatures Retrievals into the Lower Thermosphere Using an Inversion Approach

    NASA Astrophysics Data System (ADS)

    Bandoro, J.; Sica, R. J.; Argall, S.

    2012-12-01

    An important aspect of solar terrestrial relations is the coupling between the lower and upper atmosphere-ionosphere system. The coupling is evident in the general circulation of the atmosphere, where waves generate in the lower atmosphere play an important role in the dynamics of the upper atmosphere, which feeds back on the lower atmosphere's circulation. To address coupling problems requires measurements over the broadest range of heights possible. A recently developed retrieval method for temperature profiles from Rayleigh-scatter lidar measurements using an inversion approach allows the upward extension of the altitude range of temperature by 10 to 15 km over the conventional method, thus producing the equivalent of increasing the systems power-aperture product by 4 times [1]. The method requires no changes to the lidar's hardware and thus, can be applied to the body of existing measurements. In addition, since the uncertainties of the retrieved temperature profile are found by a Monte Carlo error analysis, it is possible to isolate systematic and random uncertainties to model the effect of each one on the final uncertainty product for the temperature profile. This unambiguous separation of uncertainties was not previously possible as only the propagation of the statistical uncertainties are typically reported. For the Purple Crow Lidar, corrections for saturation (e.g. non-linearity) in the photocount returns, ozone extinction and background removal all contribute to the overall systematic uncertainty. Results of individually varying each systematic correction and the effect on the final temperature uncertainty through Monte Carlo realizations are presented to determine the importance for each one. For example, it was found that treatment of the background correction as a systematic versus statistical uncertainty gave results in agreement with each other. This new method is then applied to measurements obtained by the Purple Crow lidar' Rayleigh-scatter

  5. 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.

  6. Modeling stray light from rough surfaces and subsurface scatter

    NASA Astrophysics Data System (ADS)

    Harvey, James E.; Goshy, John J.; Pfisterer, Richard N.

    2014-09-01

    Over the years we have developed an adequate theory and understanding of surface scatter from smooth optical surfaces (Rayleigh-Rice), moderately rough surfaces with paraxial incident and scattered angles (Beckmann- Kirchhoff) and even for moderately rough surfaces with arbitrary incident and scattered angles where a linear systems formulation requiring a two-parameter family of surface transfer functions is required to characterize the surface scatter process (generalized Harvey-Shack). However, there is always some new material or surface manufacturing process that provides non-intuitive scatter behavior. The linear systems formulation of surface scatter is potentially useful even for these situations. In this paper we will present empirical models of several classes of rough surfaces or materials (subsurface scatter) that allow us to accurately model the scattering behavior at any incident angle from limited measured scatter data. In particular, scattered radiance appears to continue being the natural quantity that exhibits simple, elegant behavior only in direction cosine space.

  7. 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.

  8. 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.

  9. Blue Skies through a Blue Sky: an attempt to detect Rayleigh scattering in an exoplanet atmosphere from a ground-based telescope

    NASA Astrophysics Data System (ADS)

    Luchsinger, Kristen; Redfield, Seth; Cauley, Paul W.; Barman, Travis S.; Jensen, Adam G.

    2017-01-01

    When studying planetary atmospheres, scattering signatures, such as Rayleigh scattering, can often be the most easily characterized signal. This is especially true in terrestrial atmospheres, where Rayleigh scattering is the dominant spectral feature in optical wavelengths. These scattering signatures, unlike molecular or atomic line absorption, are broad and continuous, and are char- acterized by a single slope. Rayleigh scattering provides an imporant glimpse into the atmospheric composition of an exoplanet's atmosphere, and a Rayleigh scattering detection on a smaller, ground-based telescope can be a useful method to identify interesting science targets for larger, space-based telescopes.We will present observations of three exoplanets using the HYDRA multi- object spectrometer on the WIYN telescope at Kitt Peak National Observatory. We obtained two transits each for WASP 12b and GJ 3470b, and one transit for HD 189733b, for a range of wavelengths between 4500 Å and 9201 Å. A successful Rayleigh scattering detection in the atmospheres of these planets using this in- strument would represent a step forward in our current detection capabilities and open up the study of planetary atmospheres to smaller, ground-based telescopes.Data presented herein were obtained at the WIYN Observatory from telescope time allocated to NN-EXPLORE through the scientific partnership of the National Aeronautics and Space Administration, the National Science Foundation, and the National Optical Astronomy Observatory. This work was supported by a NASA WIYN PI Data Award, administered by the NASA Exoplanet Science Institute.

  10. Lattice QCD Calculation of Hadronic Light-by-Light Scattering.

    PubMed

    Green, Jeremy; Gryniuk, Oleksii; von Hippel, Georg; Meyer, Harvey B; Pascalutsa, Vladimir

    2015-11-27

    We perform a lattice QCD calculation of the hadronic light-by-light scattering amplitude in a broad kinematical range. At forward kinematics, the results are compared to a phenomenological analysis based on dispersive sum rules for light-by-light scattering. The size of the pion pole contribution is investigated for momenta of typical hadronic size. The presented numerical methods can be used to compute the hadronic light-by-light contribution to the anomalous magnetic moment of the muon. Our calculations are carried out in two-flavor QCD with the pion mass in the range of 270-450 MeV and contain so far only the diagrams with fully connected quark lines.

  11. Light-like scattering in quantum gravity

    NASA Astrophysics Data System (ADS)

    Bjerrum-Bohr, N. E. J.; Donoghue, John F.; Holstein, Barry R.; Planté, Ludovic; Vanhove, Pierre

    2016-11-01

    We consider scattering in quantum gravity and derive long-range classical and quantum contributions to the scattering of light-like bosons and fermions (spin-0, spin- 1/2 , spin-1) from an external massive scalar field, such as the Sun or a black hole. This is achieved by treating general relativity as an effective field theory and identifying the non-analytic pieces of the one-loop gravitational scattering amplitude. It is emphasized throughout the paper how modern amplitude techniques, involving spinor-helicity variables, unitarity, and squaring relations in gravity enable much simplified computations. We directly verify, as predicted by general relativity, that all classical effects in our computation are universal (in the context of matter type and statistics). Using an eikonal procedure we confirm the post-Newtonian general relativity correction for light-like bending around large stellar objects. We also comment on treating effects from quantum ℏ dependent terms using the same eikonal method.

  12. Light Scattering based detection of food pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The current methods for detecting foodborne pathogens are mostly destructive (i.e., samples need to be pretreated), and require time, personnel, and laboratories for analyses. Optical methods including light scattering based techniques have gained a lot of attention recently due to its their rapid a...

  13. Distinguishing morphological changes with polarized light scattering

    SciTech Connect

    Johnson, T. M.; Aida, T.; Carpenter, S.; Freyer, J. P.; Mourant, J. R.

    2002-01-01

    Results of work determining how different biological structures contribute to light scattering will be presented. Further, measurements of phantoms that mimic structural changes expected in vivo will be presented. It is found that polarized measurements can discriminate between phantoms with similar properties.

  14. Cooperative light scattering in any dimension

    NASA Astrophysics Data System (ADS)

    Hill, Tyler; Sanders, Barry C.; Deng, Hui

    2017-03-01

    We present a theory of cooperative light scattering valid in any dimension: connecting theories for an open line, open plane, and open space in the nonrelativistic regime. This theory includes near-field and dipole-orientation effects, highlighting how field-mode confinement controls the phenomena. We present an experimental implementation for planar collective effects.

  15. 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.

  16. Statistical-thermodynamic model for light scattering from eye lens protein mixtures.

    PubMed

    Bell, Michael M; Ross, David S; Bautista, Maurino P; Shahmohamad, Hossein; Langner, Andreas; Hamilton, John F; Lahnovych, Carrie N; Thurston, George M

    2017-02-07

    We model light-scattering cross sections of concentrated aqueous mixtures of the bovine eye lens proteins γB- and α-crystallin by adapting a statistical-thermodynamic model of mixtures of spheres with short-range attractions. The model reproduces measured static light scattering cross sections, or Rayleigh ratios, of γB-α mixtures from dilute concentrations where light scattering intensity depends on molecular weights and virial coefficients, to realistically high concentration protein mixtures like those of the lens. The model relates γB-γB and γB-α attraction strengths and the γB-α size ratio to the free energy curvatures that set light scattering efficiency in tandem with protein refractive index increments. The model includes (i) hard-sphere α-α interactions, which create short-range order and transparency at high protein concentrations, (ii) short-range attractive plus hard-core γ-γ interactions, which produce intense light scattering and liquid-liquid phase separation in aqueous γ-crystallin solutions, and (iii) short-range attractive plus hard-core γ-α interactions, which strongly influence highly non-additive light scattering and phase separation in concentrated γ-α mixtures. The model reveals a new lens transparency mechanism, that prominent equilibrium composition fluctuations can be perpendicular to the refractive index gradient. The model reproduces the concave-up dependence of the Rayleigh ratio on α/γ composition at high concentrations, its concave-down nature at intermediate concentrations, non-monotonic dependence of light scattering on γ-α attraction strength, and more intricate, temperature-dependent features. We analytically compute the mixed virial series for light scattering efficiency through third order for the sticky-sphere mixture, and find that the full model represents the available light scattering data at concentrations several times those where the second and third mixed virial contributions fail. The model

  17. Statistical-thermodynamic model for light scattering from eye lens protein mixtures

    NASA Astrophysics Data System (ADS)

    Bell, Michael M.; Ross, David S.; Bautista, Maurino P.; Shahmohamad, Hossein; Langner, Andreas; Hamilton, John F.; Lahnovych, Carrie N.; Thurston, George M.

    2017-02-01

    We model light-scattering cross sections of concentrated aqueous mixtures of the bovine eye lens proteins γB- and α-crystallin by adapting a statistical-thermodynamic model of mixtures of spheres with short-range attractions. The model reproduces measured static light scattering cross sections, or Rayleigh ratios, of γB-α mixtures from dilute concentrations where light scattering intensity depends on molecular weights and virial coefficients, to realistically high concentration protein mixtures like those of the lens. The model relates γB-γB and γB-α attraction strengths and the γB-α size ratio to the free energy curvatures that set light scattering efficiency in tandem with protein refractive index increments. The model includes (i) hard-sphere α-α interactions, which create short-range order and transparency at high protein concentrations, (ii) short-range attractive plus hard-core γ-γ interactions, which produce intense light scattering and liquid-liquid phase separation in aqueous γ-crystallin solutions, and (iii) short-range attractive plus hard-core γ-α interactions, which strongly influence highly non-additive light scattering and phase separation in concentrated γ-α mixtures. The model reveals a new lens transparency mechanism, that prominent equilibrium composition fluctuations can be perpendicular to the refractive index gradient. The model reproduces the concave-up dependence of the Rayleigh ratio on α/γ composition at high concentrations, its concave-down nature at intermediate concentrations, non-monotonic dependence of light scattering on γ-α attraction strength, and more intricate, temperature-dependent features. We analytically compute the mixed virial series for light scattering efficiency through third order for the sticky-sphere mixture, and find that the full model represents the available light scattering data at concentrations several times those where the second and third mixed virial contributions fail. The model

  18. Quasi-Elastic Light Scattering in Ophthalmology

    NASA Astrophysics Data System (ADS)

    Ansari, Rafat R.

    The eye is not just a "window to the soul"; it can also be a "window to the human body." The eye is built like a camera. Light which travels from the cornea to the retina traverses through tissues that are representative of nearly every tissue type and fluid type in the human body. Therefore, it is possible to diagnose ocular and systemic diseases through the eye. Quasi-elastic light scattering (QELS) also known as dynamic light scattering (DLS) is a laboratory technique routinely used in the characterization of macromolecular dispersions. QELS instrumentation has now become more compact, sensitive, flexible, and easy to use. These developments have made QELS/DLS an important tool in ophthalmic research where disease can be detected early and noninvasively before the clinical symptoms appear.

  19. 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).

  20. 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.

  1. One centimeter spatial resolution temperature measurements in a nuclear reactor using Rayleigh scatter in optical fiber

    NASA Astrophysics Data System (ADS)

    Sang, A. K.; Gifford, D. K.; Dickerson, B. D.; Fielder, B. F.; Froggatt, M. E.

    2007-07-01

    We present the use of swept wavelength interferometry for distributed fiber-optic temperature measurements in a Nuclear Reactor. The sensors consisted of 2 m segments of commercially available, single mode optical fibers. The interrogation technique is based on measuring the spectral shift of the intrinsic Rayleigh backscatter signal along the optical fiber and converting the spectral shift to temperature.

  2. 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.

  3. 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.

  4. A fourier tool for the analysis of coherent light scattering by bio-optical nanostructures.

    PubMed

    Prum, Richard O; Torres, Rodolfo H

    2003-08-01

    The fundamental dichotomy between incoherent (phase independent) and coherent (phase dependent) light scattering provides the best criterion for a classification of biological structural color production mechanisms. Incoherent scattering includes Rayleigh, Tyndall, and Mie scattering. Coherent scattering encompasses interference, reinforcement, thin-film reflection, and diffraction. There are three main classes of coherently scattering nanostructures-laminar, crystal-like, and quasi-ordered. Laminar and crystal-like nanostructures commonly produce iridescence, which is absent or less conspicuous in quasi-ordered nanostructures. Laminar and crystal-like arrays have been analyzed with methods from thin-film optics and Bragg's Law, respectively, but no traditional methods were available for the analysis of color production by quasi-ordered arrays. We have developed a tool using two-dimensional (2D) Fourier analysis of transmission electron micrographs (TEMs) that analyzes the spatial variation in refractive index (available from the authors). This Fourier tool can examine whether light scatterers are spatially independent, and test whether light scattering can be characterized as predominantly incoherent or coherent. The tool also provides a coherent scattering prediction of the back scattering reflectance spectrum of a biological nanostructure. Our applications of the Fourier tool have falsified the century old hypothesis that the non-iridescent structural colors of avian feather barbs and skin are produced by incoherent Rayleigh or Tyndall scattering. 2D Fourier analysis of these quasi-ordered arrays in bird feathers and skin demonstrate that these non-iridescent colors are produced by coherent scattering. No other previous examples of biological structural color production by incoherent scattering have been tested critically with either analysis of scatterer spatial independence or spectrophotometry. The Fourier tool is applied here for the first time to coherent

  5. Impact of Rayleigh backscattering on Stimulated Brillouin Scattering threshold evaluation for 10 Gb/s NRZ-OOK signals.

    PubMed

    Ferrario, M; Marazzi, Lucia; Boffi, Pierpaolo; Righetti, Aldo; Martinelli, Mario

    2009-09-28

    At bit rates comparable with the Brillouin shift, i.e. higher than 10 Gbit/s, the signal and the Brillouin backscattered spectra partially overlap. This implies an interaction between different scattering phenomena occurring through out the optical fiber. In particular we believe that an evaluation of how Rayleigh backscattered components of the modulated signal are subjected to Stokes gain is required. This interaction may lead to an increased backscattered power, which in turn will affect Brillouin threshold estimation. We experimentally verified a decrease of Stimulated Brillouin Scattering (SBS) threshold for 10 Gb/s NRZ-OOK signals with respect to theoretical predictions. Simulations carried out with a numerical model of SBS, accounting for Rayleigh contributions, well predict measured backscattered power levels. On the other hand we also experimentally verified that this SBS threshold decrease does not degrade transmission system performance. Indeed, measured BER curves put into evidence a penalty reduction for signal powers just before the saturation regime, which should be usefully taken into consideration in optical systems power budget planning.

  6. New technique for retrieval of atmospheric temperature profiles from Rayleigh-scatter lidar measurements using nonlinear inversion.

    PubMed

    Khanna, Jaya; Bandoro, Justin; Sica, R J; McElroy, C Thomas

    2012-11-20

    The conventional method of calculating atmospheric temperature profiles using Rayleigh-scattering lidar measurements has limitations that necessitate abandoning temperatures retrieved at the greatest heights, due to the assumption of a pressure value required to initialize the integration at the highest altitude. An inversion approach is used to develop an alternative way of retrieving nightly atmospheric temperature profiles from the lidar measurements. Measurements obtained by the Purple Crow lidar facility located near The University of Western Ontario are used to develop and test this new technique. Our results show temperatures can be reliably retrieved at all heights where measurements with adequate signal-to-noise ratio exist. A Monte Carlo technique was developed to provide accurate estimates of both the systematic and random uncertainties for the retrieved nightly average temperature profile. An advantage of this new method is the ability to seed the temperature integration from the lowest rather than the greatest height, where the variability of the pressure is smaller than in the mesosphere or lower thermosphere and may in practice be routinely measured by a radiosonde, rather than requiring a rocket or satellite-borne measurement. Thus, this new technique extends the altitude range of existing Rayleigh-scatter lidars 10-15 km, producing the equivalent of four times the power-aperture product.

  7. Comprehensive model for studying noise induced by self-homodyne detection of backward Rayleigh scattering in optical fibers.

    PubMed

    Fleyer, Michael; Cahill, James P; Horowitz, Moshe; Menyuk, Curtis R; Okusaga, Olukayode

    2015-10-05

    Backward Rayleigh scattering in optical fibers due to the fluctuations that are "frozen-in" to the fiber during the manufacturing process may limit the performance of optical sensors and bidirectional coherent optical communication systems. In this manuscript we describe a comprehensive model for studying intensity noise induced by spontaneous Rayleigh backscattering in optical systems that are based on self-homodyne detection. Our model includes amplitude and frequency noise of the laser source, random distribution of the scatterers along the fiber, and phase noise induced in fibers due to thermal and mechanical fluctuations. The model shows that at frequencies above about 10 kHz the noise spectrum is determined by the laser white frequency noise. The laser flicker frequency noise becomes the dominant effect at lower frequencies. The noise amplitude depends on the laser polarization. A very good agreement between theory and experiment is obtained for fibers with a length between 500 m to 100 km and for a laser with a linewidth below 5 kHz.

  8. Zeno: Critical Fluid Light Scattering Experiment

    NASA Technical Reports Server (NTRS)

    Gammon, Robert W.; Shaumeyer, J. N.; Briggs, Matthew E.; Boukari, Hacene; Gent, David A.; Wilkinson, R. Allen

    1996-01-01

    The Zeno (Critical Fluid Light Scattering) experiment is the culmination of a long history of critical fluid light scattering in liquid-vapor systems. The major limitation to making accurate measurements closer to the critical point was the density stratification which occurs in these extremely compressible fluids. Zeno was to determine the critical density fluctuation decay rates at a pair of supplementary angles in the temperature range 100 mK to 100 (mu)K from T(sub c) in a sample of xenon accurately loaded to the critical density. This paper gives some highlights from operating the instrument on two flights March, 1994 on STS-62 and February, 1996 on STS-75. More detail of the experiment Science Requirements, the personnel, apparatus, and results are displayed on the Web homepage at http://www.zeno.umd.edu.

  9. Inelastic light scattering from correlated electrons

    NASA Astrophysics Data System (ADS)

    Devereaux, Thomas P.; Hackl, Rudi

    2007-01-01

    Inelastic light scattering is an intensively used tool in the study of electronic properties of solids. Triggered by the discovery of high-temperature superconductivity in the cuprates and by new developments in instrumentation, light scattering in both the visible (Raman effect) and x-ray part of the electromagnetic spectrum has become a method complementary to optical (infrared) spectroscopy while providing additional and relevant information. The main purpose of the review is to position Raman scattering with regard to single-particle methods like angle-resolved photoemission spectroscopy, and other transport and thermodynamic measurements in correlated materials. Particular focus will be placed on photon polarizations and the role of symmetry to elucidate the dynamics of electrons in different regions of the Brillouin zone. This advantage over conventional transport (usually measuring averaged properties) provides new insights into anisotropic and complex many-body behavior of electrons in various systems. Recent developments in the theory of electronic Raman scattering in correlated systems and experimental results in paradigmatic materials such as the A15 superconductors, magnetic and paramagnetic insulators, compounds with competing orders, as well as the cuprates with high superconducting transition temperatures are reviewed. An overview of the manifestations of complexity in the Raman response due to the impact of correlations and developing competing orders is presented. In a variety of materials, observations which may be understood and a summary of important open questions that pave the way to a detailed understanding of correlated electron systems, are discussed.

  10. 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.

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

    PubMed

    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

    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.

  13. Influence of convection on the stimulated concentration light scattering

    NASA Astrophysics Data System (ADS)

    Burkhanov, I. S.; Krivokhizha, S. V.; Chaikov, L. L.

    2016-08-01

    A non-linear growth of the scattering intensity and the frequency shift of the spectral lines of scattered light close to the half-width of the spontaneous scattering in the back scattering of light in the suspensions of latex nanoparticles in water were found. It proves that we observed a stimulated scattering of light on the particle concentration variations. Influence of convection is taken into account using Doppler measurements of fluid flow.

  14. 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.

  15. Visible Inelastic Light Scattering from Metals

    NASA Astrophysics Data System (ADS)

    Wilkinson, Roger Allen

    In this work we studied the spectral shape of the intense continuum of light scattered inelastically from "bare" metals used in Surface Enhanced Raman Scattering. We derived cross sections, presented their spectral properties, and experimentally sought to characterize the observable spectral shape. Three scattering cross sections are derived. The development includes exposure of assumptions and limitations in the derivation. Elucidated are: contributions due to the few angstrom drastic spatial and polarization variations of the applied electromagnetic field at jellium metal surfaces; fluctuation induced light scattering, such as, spin density, charge density (plasmon and single electron), and current density fluctuations; and the light coupling operators that arise from a choice of gauge used in photoemission rather than the customary Coulomb gauge. The result is a set of matrix elements that carry the important physics of light scattering by metallic electrons, and that is more complete than is found in the Surface Enhanced Raman literature. Using one of these matrix elements in the electric dipole approximation we have developed a quantum chemistry computer algorithm to evaluate the strength of light interaction with any metal surface which can be modeled as a cluster. The algorithm uses spd Slater-type bases and can study transition and noble metals. It was tested on some model systems. A formalism is presented for further developing the algorithm to calculate adsorbed molecular vibrational Raman cross sections in the limit of the long wavelength electric dipole approximation. We further present known continuum spectral shapes from familiar light coupling operators (a subset of those we derived) and associate them with our experimentally observed spectral shapes. In the experimental study of spectral shapes we found the mechanical disorder, due to cold working smooth metals during polishing, to correlate with the strength of the continuum. Using microscopic

  16. 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.

  17. Resonance Rayleigh scattering and resonance non-linear scattering method for the determination of aminoglycoside antibiotics with water solubility CdS quantum dots as probe.

    PubMed

    Liu, Zhengwen; Liu, Shaopu; Wang, Lei; Peng, Juanjuan; He, Youqiu

    2009-09-15

    In pH 6.6 Britton-Robinson buffer medium, the CdS quantum dots capped by thioglycolic acid could react with aminoglycoside (AGs) antibiotics such as neomycin sulfate (NEO) and streptomycin sulfate (STP) to form the large aggregates by virtue of electrostatic attraction and the hydrophobic force, which resulted in a great enhancement of resonance Rayleigh scattering (RRS) and resonance non-linear scattering such as second-order scattering (SOS) and frequency doubling scattering (FDS). The maximum scattering peak was located at 310 nm for RRS, 568 nm for SOS and 390 nm for FDS, respectively. The enhancements of scattering intensity (DeltaI) were directly proportional to the concentration of AGs in a certain ranges. A new method for the determination of trace NEO and STP using CdS quantum dots probe was developed. The detection limits (3 sigma) were 1.7 ng mL(-1) (NEO) and 4.4 ng mL(-1) (STP) by RRS method, were 5.2 ng mL(-1) (NEO) and 20.9 ng mL(-1) (STP) by SOS method and were 4.4 ng mL(-1) (NEO) and 25.7 ng mL(-1) (STP) by FDS method, respectively. The sensitivity of RRS method was the highest. The optimum conditions and influence factors were investigated. In addition, the reaction mechanism was discussed.

  18. 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.

  19. Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

    NASA Astrophysics Data System (ADS)

    Jacobson, C. M.; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A.

    2016-11-01

    The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

  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. 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.

  2. 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

    2016-06-05

    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.

  3. A rapid and sensitive resonance Rayleigh scattering spectra method for the determination of quinolones in human urine and pharmaceutical preparation.

    PubMed

    Qiao, Man; Wang, Yaqiong; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Zhu, Jinghui; Hu, Xiaoli

    2015-03-01

    A new method based on resonance Rayleigh scattering (RRS) was proposed for the determination of quinolones (QNS) at the nanogram level. In pH 3.3-4.4 Britton-Robinson buffer medium, quinolones such as ciprofloxacin, pipemidic acid (PIP), lomefloxacin (LOM), norfloxacin (NOR) and sarafloxacin (SAR) were protonated and reacted with methyl orange (MO) to form an ion-pair complex, which then further formed a six-membered ring chelate with Pd(II). As a result, new RRS spectra appeared and the RRS intensities were enhanced greatly. RRS spectral characteristics of the MO-QNS-Pd(II) systems, the optimum conditions for the reaction, and the influencing factors were investigated. Under optimum conditions, the scattering intensity (∆I) increments were directly proportional to the concentration of QNS with in certain ranges. The method had high sensitivity, and the detection limits (3σ) ranged from 6.8 to 12.6 ng/mL. The proposed method had been successfully applied for the determination of QNS in pharmaceutical formulations and human urine samples. In addition, the mechanism of the reaction system was discussed based on IR, absorption and fluorescence spectral studies. The reasons for the enhancement of scattering spectra were discussed in terms of fluorescence-scattering resonance energy transfer, hydrophobicity and molecular size.

  4. Ultraviolet Rayleigh-Mie lidar with Mie-scattering correction by Fabry-Perot etalons for temperature profiling of the troposphere.

    PubMed

    Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao

    2005-03-01

    A Rayleigh-Mie-scattering lidar system at an eye-safe 355-nm ultraviolet wavelength that is based on a high-spectral-resolution lidar technique is demonstrated for measuring the vertical temperature profile of the troposphere. Two Rayleigh signals, which determine the atmospheric temperature, are filtered with two Fabry-Perot etalon filters. The filters are located on the same side of the wings of the Rayleigh-scattering spectrum and are optically constructed with a dual-pass optical layout. This configuration achieves a high rejection rate for Mie scattering and reasonable transmission for Rayleigh scattering. The Mie signal is detected with a third Fabry-Perot etalon filter, which is centered at the laser frequency. The filter parameters were optimized by numerical calculation; the results showed a Mie rejection of approximately -45 dB, and Rayleigh transmittance greater than 1% could be achieved for the two Rayleigh channels. A Mie correction method is demonstrated that uses an independent measure of the aerosol scattering to correct the temperature measurements that have been influenced by the aerosols and clouds. Simulations and preliminary experiments have demonstrated that the performance of the dual-pass etalon and Mie correction method is highly effective in practical applications. Simulation results have shown that the temperature errors that are due to noise are less than 1 K up to a height of 4 km for daytime measurement for 300 W m(-2) sr(-1) microm(-1) sky brightness with a lidar system that uses 200 mJ of laser energy, a 3.5-min integration time, and a 25-cm telescope.

  5. Study on the interaction between ligustrazine and 12-tungstophosphoric acid using resonance Rayleigh scattering and resonance nonlinear scattering spectra, and its analytical applications.

    PubMed

    Li, Junbo; Yang, Xiaoli; Yang, Jinxiang; Lai, Lina

    2015-08-01

    In an HCl medium (pH 1.5), ligustrazine (2,3,5,6-tetramethylpyrazine, TMP) reacted with 12-tungstophosphoric acid (TP) to form a 3 : 1 ion-association complex. As a result, the intensities of resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were greatly enhanced and new scattering spectra appeared. The maximum RRS, SOS and FDS wavelengths of the ion-association complexes were located at 379, 738 and 395 nm, respectively. The scattering intensity increments (ΔIRRS , ΔISOS and ΔIFDS ) were directly proportional to the concentration of ligustrazine within certain ranges. The detection limits (3σ) of RRS, SOS and FDS were 1.6, 3.2 and 2.8 ng/mL. Optimal conditions for the RRS method and factors influencing the method were discussed, and the structure of the ion-association complex and the reaction mechanism were investigated. Transmission electron microscopy (TEM) was used to characterize the structures of the ion-association complex. Based on the ion-association reaction and its spectral response, a rapid, simple and sensitive RRS method for the determination of TMP was developed. It was applied to the determination of TMP in tablet and urine samples with satisfactory results.

  6. Single scattering solution for radiative transfer through Rayleigh and aerosol atmosphere

    NASA Technical Reports Server (NTRS)

    Otterman, J.

    1977-01-01

    A solution is presented to the radiative transfer of the solar irradiation through a turbid atmosphere, based on the single-scattering approximation, i.e., an assumption that a photon that underwent scattering either leaves the top of the atmosphere or strikes the surface. The solution depends on a special idealization of the scattering phase function of the aerosols. The equations developed are subsequently applied to analyze quantitatively the enhancement of the surface irradiation and the enhancement of the scattered radiant emittance as seen from above the atmosphere, caused by the surface reflectance and atmospheric back scattering. An order of magnitude error analysis is presented.

  7. 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.

  8. 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.

  9. Raman fiber lasers with a random distributed feedback based on Rayleigh scattering

    SciTech Connect

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

    2010-09-15

    We demonstrate lasing based on a random distributed feedback due to the Raman amplified Rayleigh backscattering in different types of cavities with and without conventional point-action reflectors. Quasistationary generation of a narrowband spectrum is achieved despite the random nature of the feedback. The generated spectrum is localized at the reflection or gain spectral maxima in schemes with and without point reflectors, respectively. The length limit for a conventional cavity and the minimal pump power required for the lasing based purely on a random distributed feedback are determined.

  10. Scattering of light on rippled surfaces

    NASA Astrophysics Data System (ADS)

    Hilarov, V. L.; Korsukov, V. E.; Korsukova, M. M.; Shcherbakov, I. P.

    2015-06-01

    Thin platinum foils and ribbons of the amorphous alloy Fe77Ni1Si9B13 with fractal surfaces made of unidirectional multiscale surface ripples have been prepared. The surface relief and atomic structure of these foils have been investigated by low-energy electron diffraction, atomic force microscopy, and scanning tunnelling microscopy. It has been shown that Pt foils with a fractal surface relief have the prospect for application as reflective diffraction gratings. A model has been proposed and used to calculate the light scattering on unidirectional rippled surface structures of Pt foils.

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

    PubMed

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

    2015-04-05

    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 2.29×10(5) 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.

  12. 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.

  13. 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.

  14. Refinement of the Compton-Rayleigh scatter ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Campbell, J. L.; Perrett, G. M.; Maxwell, J. A.; Nield, E.; Gellert, R.; King, P. L.; Lee, M.; O'Meara, J. M.; Pradler, I.

    2013-05-01

    Spectra from the Mars rover alpha particle X-ray spectrometers contain the elastic and inelastic scatter peaks of the plutonium L X-rays emitted by the instrument's 244Cm source. Various spectrum fitting approaches are tested using the terrestrial twin of the APXS instrument on the Mars Science Laboratory Curiosity rover, in order to provide accurate extraction of the Lα and Lβ Compton/Rayleigh intensity ratios, which can provide information about light "invisible" constituents such as water in geological samples. A well-defined dependence of C/R ratios upon mean sample atomic number is established using a large and varied set of geochemical reference materials, and the accuracy of this calibration is examined. Detailed attention is paid to the influence of the rubidium and strontium peaks which overlap the Lα scatter peaks. Our Monte Carlo simulation code for prediction of C/R ratios from element concentrations is updated. The ratio between measured and simulated C/R ratios provides a second means of calibration.

  15. 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.

  16. 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.

  17. 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

    2016-06-05

    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.

  18. Light scattering in artificial fog and simulated with light scattering filter.

    PubMed

    Ikaunieks, Gatis; Colomb, Michéle; Ozolinsh, Maris

    2009-05-01

    Disability glare, affecting e.g. road safety at night, may result either from intraocular light scattering or from external conditions such as fog. Measurements were made of light scattering in fog and compared with intraocular straylight data for normal eyes and eyes with simulated cataract. All measurements were made with a direct compensation flicker method. To estimate light scattering levels in fog, straylight measurements were carried in a fog chamber for different densities of fog. Density was characterized by the meteorological term visibility V and ranged from 7 to 25. Test distance for measurements in the fog was constant at 5 m. Cataract eye conditions were simulated by placing a light scattering polymer dispersed liquid crystal (PDLC) filter with scatterers of submicron size in front of the normal eye. All measurements were made using each of three broad-band color stimuli - red, green and blue (produced either with LEDs or a color CRT monitor). Differences were found in both the level and the spectral characteristics of scattering under the different conditions. The measured values of the straylight parameter, s, in artificial fog showed no noticeable spectral dependence at any visibility range. Increasing the visibility range caused an exponential decrease in the straylight. Intraocular straylight measured with the clear eye showed an increase at the red and blue ends of the spectrum as compared to the green. Straylight measured using PDLC plates with different transparency levels showed a spectral dependence which decreased with wavelength. The scattering introduced by the PDLC plate therefore failed to give a valid simulation of cataract and fog conditions for polychromatic stimuli, due to its erroneous spectral dependence.

  19. 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.

  20. Q-space analysis of light scattering by ice crystals

    NASA Astrophysics Data System (ADS)

    Heinson, Yuli W.; Maughan, Justin B.; Ding, Jiachen; Chakrabarti, Amitabha; Yang, Ping; Sorensen, Christopher M.

    2016-12-01

    Q-space analysis is applied to extensive simulations of the single-scattering properties of ice crystals with various habits/shapes over a range of sizes. The analysis uncovers features common to all the shapes: a forward scattering regime with intensity quantitatively related to the Rayleigh scattering by the particle and the internal coupling parameter, followed by a Guinier regime dependent upon the particle size, a complex power law regime with incipient two dimensional diffraction effects, and, in some cases, an enhanced backscattering regime. The effects of significant absorption on the scattering profile are also studied. The overall features found for the ice crystals are similar to features in scattering from same sized spheres.

  1. On-Resonance Fluorescence, Resonance Rayleigh Scattering, and Ratiometric Resonance Synchronous Spectroscopy of Molecular- and Quantum Dot-Fluorophores.

    PubMed

    Siriwardana, Kumudu; Nettles, Charles B; Vithanage, Buddhini C N; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao

    2016-09-20

    Existing studies on molecular fluorescence have almost exclusively been focused on Stokes-shifted fluorescence spectroscopy (SSF) in which the emitted photon is detected at the wavelengths longer than that for the excitation photons. Information on fluorophore on-resonance fluorescence (ORF) and resonance Rayleigh scattering (RRS) is limited and often problematic due to the complex interplay of the fluorophore photon absorption, ORF emission, RRS, and solvent Rayleigh scattering. Reported herein is a relatively large-scale systematic study on fluorophore ORF and RRS using the conventional UV-vis extinction and SSF measurements in combination with the recently reported ratiometric resonance synchronous spectroscopic (R2S2, pronounced as "R-Two-S-Two") method. A series of fundamental parameters including fluorophore ORF cross sections and quantum yields have been quantified for the first time for a total of 12 molecular and 6 semiconductor quantum dot (QD) fluorophores. All fluorophore spectra comprise a well-defined Gaussian peak with a full width at half-maximum ranging from 4 to 30 nm. However, the RRS features of fluorophores differ drastically. The effect of fluorophore aggregation on its RRS, UV-vis, R2S2, and SSF spectra was also discussed. This work highlights the critical importance of the combined UV-vis extinction, SSF, and R2S2 spectroscopic measurements for material characterizations. The method and insights described in this work can be directly used for improving the reliability of RRS spectroscopic methods in chemical analysis. In addition, it should pave the way for developing novel R2S2-based analytical applications.

  2. Atom-interferometric studies of light scattering

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    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 2ℏk at t=2T . Matter wave interference is associated with the formation of a density grating with period λ/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-δT 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 δT . 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 larger than the recoil

  3. Industrial Particle Size Measurement Using Light Scattering

    NASA Astrophysics Data System (ADS)

    Muly, E. C.; Frock, H. N.

    1980-12-01

    The precise knowledge of particle size and particle size distribution is fundamental to the control of a wide variety of industrial processes. Processing steps as diverse as crystallization, grinding, emulsification, and atomization, produce particles in the size range .1 to 1000 micrometers in diameter. While the object of some processes may be the production of particles of specified sizes, e.g., abrasives and glass beads, other processes may require particle size control for process efficiency, e.g., crystallization, and still others for control of final product quality, e.g., minerals, cement, and ceramics. In many processes more than one of these reasons may be important. A line of instruments has been developed using light scattering to measure various parameters of particulate distributions. These instruments employ laser illumination of a flowing stream of particles, producing Fraunhofer diffraction patterns which are processed both optically and electronically with unique, proprietary techniques. Various parameters of the particle size distribution are measured. The measurement is both rapid and precise. This paper will cover the importance of particle size measurements in various processes, different types of measurement methods, and the application of light scattering technology to size determinations in wet slurries and dry powders. A number of specific applications will be discussed encompassing minerals grinding, Portland cement, and rolling mill emulsions. Some references will be made to energy savings through automation.

  4. Fourier transform light scattering angular spectroscopy using digital inline holography.

    PubMed

    Kim, Kyoohyun; Park, YongKeun

    2012-10-01

    A simple and practical method for measuring the angle-resolved light scattering (ARLS) from individual objects is reported. Employing the principle of inline holography and a Fourier transform light scattering technique, both the static and dynamic scattering patterns from individual micrometer-sized objects can be effectively and quantitatively obtained. First, the light scattering measurements were performed on individual polystyrene beads, from which the refractive index and diameter of each bead were retrieved. Also, the measurements of the static and dynamic light scattering from intact human red blood cells are demonstrated. Using the present method, an existing microscope can be directly transformed into a precise instrument for ARLS measurements.

  5. Sizing aerosolized fractal nanoparticle aggregates through Bayesian analysis of wide-angle light scattering (WALS) data

    NASA Astrophysics Data System (ADS)

    Huber, Franz J. T.; Will, Stefan; Daun, Kyle J.

    2016-11-01

    Inferring the size distribution of aerosolized fractal aggregates from the angular distribution of elastically scattered light is a mathematically ill-posed problem. This paper presents a procedure for analyzing Wide-Angle Light Scattering (WALS) data using Bayesian inference. The outcome is probability densities for the recovered size distribution and aggregate morphology parameters. This technique is applied to both synthetic data and experimental data collected on soot-laden aerosols, using a measurement equation derived from Rayleigh-Debye-Gans fractal aggregate (RDG-FA) theory. In the case of experimental data, the recovered aggregate size distribution parameters are generally consistent with TEM-derived values, but the accuracy is impaired by the well-known limited accuracy of RDG-FA theory. Finally, we show how this bias could potentially be avoided using the approximation error technique.

  6. 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.

  7. Flat amplitude multiwavelength Brillouin-Raman comb fiber laser in Rayleigh-scattering-enhanced linear cavity.

    PubMed

    Zamzuri, A K; Mahdi, M A; Ahmad, A; Md Ali, M I; Al-Mansoori, M H

    2007-03-19

    We investigate the amplitude flatness of Rayleigh-assisted Brillouin-Raman comb laser in a linear cavity in which feedbacks are formed by high-reflectivity mirror. The optimization of Brillouin pump power and wavelength is very crucial in order to obtain a uniform power level between Stokes lines. The Brillouin pump must have a relatively large power and its wavelength must be located closer to the Raman peak gain region. The flat-amplitude bandwidth is also determined by the choice of Raman pump wavelengths. A flat-amplitude bandwidth of 30.7 nm from 1527.32 to 1558.02 nm is measured when Raman pump wavelengths are set to 1435 and 1450 nm. 357 uniform Brillouin Stokes lines with 0.086 nm spacing are generated across the wavelength range. The average signal-to-noise ratio of 17 dB is obtained for all the Brillouin Stokes lines.

  8. 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

  9. Distributed temperature and strain discrimination with stimulated brillouin scattering and rayleigh backscatter in an optical fiber.

    PubMed

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

    2013-01-31

    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.

  10. Near-Field Nanofluid Concentration Measurement by Rayleigh Particle Scattering Bragg Grating Evanescent Wave

    NASA Astrophysics Data System (ADS)

    Huang, Xue-Feng; Li, Sheng-Ji

    2014-04-01

    We report an approach to detect near-field nanofluid concentration by scattering Bragg grating evanescent wave (EW). Since the suspended nanoparticles can enhance the scattering intensity of the EW from the thinned and tapered fiber with Bragg grating, the reflectance ratio of Bragg grating is dependent on the corresponding refractive index (RI) of the nanofluid at different nanoparticle volume fraction. A critical reflectance ratio measurement identifies the nanofluid concentration. Theory and simulation of scattering Bragg grating EW was analyzed. The scattering Bragg grating EW fiber sensing probe was designed and fabricated by the wet chemical etching method, and calibration was made by several chemical solutions without suspended nanoparticles. The example application of the nanofluid containing dispersed 40 nm SiO2 nanoparticles demonstrates the feasibility. The reflectance ratio decreases by over 3.2% with the nanofluid concentration increasing from 0.25 wt.% to 4 wt.%, while the temperature disturbance can be negligible.

  11. Determination of light absorption, scattering and anisotropy factor of a highly scattering medium using backscattered circularly polarized light

    NASA Astrophysics Data System (ADS)

    Xu, M.; Alrubaiee, M.; Gayen, S. K.; Alfano, R. R.

    2007-02-01

    The absorption coefficient, the scattering coefficient and the anisotropy factor of a highly scattering medium are determined using the diffuse reflectance of an obliquely incident beam of circularly polarized light. This approach determines both the anisotropy factor and the cutoff size parameter for the fractal continuous scattering medium such as biological tissue and tissue phantoms from depolarization of the backscattered light.

  12. 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

  13. Resonance Rayleigh scattering, frequency doubling scattering and absorption spectrum of the interaction for mebendazole with 12-tungstophosphoric acid and its analytical applications.

    PubMed

    Tian, Fengling; Yang, Jidong; Huang, Wei; Zhou, Shang; Yao, Gengyang

    2013-12-01

    The interaction of mebendazole (MBZ) with 12-tungstophosphoric acid (TP) has been investigated by using resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS) combining with absorption spectrum. In pH 1.0 HCl medium, MBZ reacted with TP to form 3:1 ion-association complex. As a result, not only the spectrum of absorption was changed, but also the intensities of RRS and FDS were enhanced greatly. The maximum RRS, FDS and absorption wavelengths are located at 372, 392 and 260 nm, respectively. The increments of scattering intensity (ΔI) and absorption (ΔA) are directly proportional to the concentrations of MBZ in certain ranges. The detection limits (3σ) of RRS, FDS and absorption are 0.56, 0.86 and 130.16 ng/mL, respectively. The sensitivity of RRS method is higher than FDS and absorption methods. The optimum conditions of RRS method and the influence factors were discussed in the paper, in addition, the structure of ion-association complex and the reaction mechanism were investigated. Based on the ion-association reaction and its spectral response, the rapid, simple and sensitive RRS method for the determination of MBZ has been developed.

  14. 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.

  15. 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…

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  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. 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.

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

    PubMed

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

    2014-05-28

    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.

  3. 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

  4. 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.

  5. Simulation model of absorption and scattering properties of laser light applied to urban aerosols over the city of Popayan, Colombia

    NASA Astrophysics Data System (ADS)

    Bastidas, Alvaro E.; Rodriguez, Edith; Jaramillo, Mauricio; Solarte, Efrain

    2004-11-01

    Aerosols are among the most spatially variable components of the atmosphere, and thus their study requires their monitoring over a broad geographic range. The backscattering of light from suspended solid and liquid particles in the atmosphere obeys Mie scattering theory. Light attenuation in the spectral region from 300 to 4000 nm due to Mie scattering exceeds that due to molecular (Rayleigh) scattering and ozone absorption combined. This occurs despite the fact that aerosol particle concentrations in the atmosphere are many orders of magnitude smaller than molecular concentrations. Starting from the characteristics of urban aerosols measured over the city of Popayan, Colombia), 2° 27" N; 76° 37' W, with a PM10 particle selector, we present the results of a study of light attenuation properties generated using Matlab computer code, to simulate and predict measurements with a Lidar system operating at 514.5 nm.

  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. Fractal mechanisms of light scattering in biological tissue and cells

    NASA Astrophysics Data System (ADS)

    Xu, M.; Alfano, R. R.

    2005-11-01

    We use fractal continuous random media to model visible and near-infrared light scattering by biological tissue and cell suspensions. The power law of the reduced scattering coefficient, the anisotropy factor of scattering, and the phase function are derived with good agreement with experimental results. Implications for spectroscopic tissue diagnosis are discussed.

  8. Multiple-Fiber-Optic Probe For Light-Scattering Measurements

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans Singh; Ansari, Rafat R.

    1996-01-01

    Multiple-fiber-optical probe developed for use in measuring light scattered at various angles from specimens of materials. Designed for both static and dynamic light-scattering measurements of colloidal dispersions. Probe compact, rugged unit containing no moving parts and remains stationary during operation. Not restricted to operation in controlled, research-laboratory environment. Positioned inside or outside light-scattering chamber. Provides simultaneous measurements at small angular intervals over range of angles, made to include small scattering angles by orienting probe in appropriate direction.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. Measurement of time series variation of thermal diffusivity of magnetic fluid under magnetic field by forced Rayleigh scattering method

    NASA Astrophysics Data System (ADS)

    Motozawa, Masaaki; Muraoka, Takashi; Motosuke, Masahiro; Fukuta, Mitsuhiro

    2017-04-01

    It can be expected that the thermal diffusivity of a magnetic fluid varies from time to time after applying a magnetic field because of the growth of the inner structure of a magnetic fluid such as chain-like clusters. In this study, time series variation of the thermal diffusivity of a magnetic fluid caused by applying a magnetic field was investigated experimentally. For the measurement of time series variation of thermal diffusivity, we attempted to apply the forced Rayleigh scattering method (FRSM), which has high temporal and high spatial resolution. We set up an optical system for the FRSM and measured the thermal diffusivity. A magnetic field was applied to a magnetic fluid in parallel and perpendicular to the heat flux direction, and the magnetic field intensity was 70 mT. The FRSM was successfully applied to measurement of the time series variation of the magnetic fluid from applying a magnetic field. The results show that a characteristic configuration in the time series variation of the thermal diffusivity of magnetic fluid was obtained in the case of applying a magnetic field parallel to the heat flux direction. In contrast, in the case of applying a magnetic field perpendicular to the heat flux, the thermal diffusivity of the magnetic fluid hardly changed during measurement.

  14. 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.

  15. Scattering of Light and Surface Plasmon Polaritons from Rough Surfaces

    DTIC Science & Technology

    2013-06-14

    AFRL-RV-PS- AFRL-RV-PS- TR-2013-0049 TR-2013-0049 SCATTERING OF LIGHT AND SURFACE PLASMON POLARITONS FROM ROUGH SURFACES Alexei A...2013 4. TITLE AND SUBTITLE Scattering of Light and Surface Plasmon Polaritons from Rough Surfaces 5a. CONTRACT NUMBER FA9453-08-C-0230 5b...of several properties of surface plasmon polaritons on structured surfaces are described, together with results for the scattering of surface plasmon

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Laser Light Scattering with Multiple Scattering Suppression Used to Measure Particle Sizes

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Tin, Padetha; Lock, James A.; Cannell, David S.; Smart, Anthony E.; Taylor, Thomas W.

    1999-01-01

    Laser light scattering is the technique of choice for noninvasively sizing particles in a fluid. The members of the Advanced Technology Development (ATD) project in laser light scattering at the NASA Lewis Research Center have invented, tested, and recently enhanced a simple and elegant way to extend the concentration range of this standard laboratory particle-sizing technique by several orders of magnitude. With this technique, particles from 3 nm to 3 mm can be measured in a solution. Recently, laser light scattering evolved to successfully size particles in both clear solutions and concentrated milky-white solutions. The enhanced technique uses the property of light that causes it to form tall interference patterns at right angles to the scattering plane (perpendicular to the laser beam) when it is scattered from a narrow laser beam. Such multiple-scattered light forms a broad fuzzy halo around the focused beam, which, in turn, forms short interference patterns. By placing two fiber optics on top of each other and perpendicular to the laser beam (see the drawing), and then cross-correlating the signals they produce, only the tall interference patterns formed by singly scattered light are detected. To restate this, unless the two fiber optics see the same interference pattern, the scattered light is not incorporated into the signal. With this technique, only singly scattered light is seen (multiple-scattered light is rejected) because only singly scattered light has an interference pattern tall enough to span both of the fiber-optic pickups. This technique is simple to use, easy to align, and works at any angle. Placing a vertical slit in front of the signal collection fibers enhanced this approach. The slit serves as an optical mask, and it significantly shortens the time needed to collect good data by selectively masking out much of the unwanted light before cross-correlation is applied.

  1. Light scattering in glasses: Non-exponential structural relaxation, boson peaks and the existence of intermediate range order

    NASA Astrophysics Data System (ADS)

    Lee, Mierie

    2000-10-01

    In order to understand the nature of the excess vibrational modes in glasses that give it a number of anomalous properties such as excess thermal and transport properties at very low temperatures, we performed a number of light scattering experiments on glasses. Light scattering from glasses in the glass transition region exhibits an anomalous Rayleigh scattering. We observe a maximum in the scattering intensity versus temperature during heating. This behavior is consistent with the presence of nanometer-scale inhomogeneities (density fluctuations) which relax at differing rates. In all cases, a hysteresis effect is seen in the light scattering between heating and cooling each sample from room temperature through the glass transition region. We suggest that this could be the source of non-exponential structural relaxation kinetics (see reference [7] from chapter 1). From several approaches, we calculated the correlation volume of these nanoscale inhomogeneities and find a typical size (~V1/3) of about 2-3nm. This is consistent with independent observations done by Raman scattering where we observed the low energy ``Boson Peak''. For the low frequency Raman spectra, all glasses show a broad feature around 0.6-3.0 THz, the so-called Boson peak. This Boson peak is associated with the existence of intermediate range order in the glass. The Boson peak is due to an increase in the vibrational density of states, over the Debye value, caused by localized excitations (phonon localization). The degree and range of disorder in the glasses is obtained in a quantitative sense from the behavior of the Boson peaks with temperature and compared to Rayleigh-Brillouin scattering data done on the same glasses. We obtain strong evidence for the existence of intermediate range order in glasses. The Raman scattering also allowed us to measure for the first time in glasses the non-coincidence effect. This effect supports the cluster model, which is necessary for the intermediate range

  2. Circular polarized incident light scattering properties at optical clearing in tissues

    NASA Astrophysics Data System (ADS)

    Chen, Dongsheng; Zeng, Nan; Wang, Yunfei; He, Honghui; Tuchin, Valery V.; Ma, Hui

    2016-09-01

    This paper focuses on polarization imaging during optical clearing process in tissues due to refractive index matching of tissue structural components. We start with some single-dispersed tissue models, composed of large spheres, small spheres, and large cylinders, respectively. Along with the simulated refractive index matching inside and outside the scatterers, the linear polarized incident photons show similar decreased depolarization. It is worth noting that the circular polarized incident light show different polarization change for different scatterers, sensitive to scatterer size and shape. For small Rayleigh-like spherical scatterers, the circular depolarization also decreases with index matching. However, the depolarization by the larger scatterers can be enhanced, supported by the photon distribution change with the index matching in the backward detection. After some extreme points, the depolarization of circular polarized photons will be suppressed until almost disappear. Furthermore, by the simulation of hybrid-dispersed models, we can find out that the transmission of circular polarized photons during optical clearing, is more sensitive to the content of smaller scatterers in the turbid medium, and also has a close relationship with the proportion of the anisotropic scatterers. We also extract a character to describe the difference of linear and circular polarized photons. The value and the change of this character can help us to explain the main scatterers contributed to the polarization features of tissue-like medium during optical clearing. The above results indicate different polarization features for different scattering systems by optical clearing, which are potentially useful for studying optical clearing by polarization methods.

  3. 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

  4. 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

    2016-06-24

    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.

  5. 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.

  6. Light scattering characterization of optical components: BRDF, BTDF, and scatter losses

    NASA Astrophysics Data System (ADS)

    Schröder, Sven; Finck, Alexander; Katsir, Dina; Zeitner, Uwe; Duparré, Angela

    2014-11-01

    Light scattering caused by imperfections of optical components can critically affect the performance of optical systems in terms of losses and image degradation. Because of the numerous potential sources of scattering such as roughness, surface and sub-surface defects, bulk inhomogeneities, as well as coatings, scattering properties must be carefully specified and measured at the wavelengths of application. Bidirectional Reflectance and Transmittance Distribution Functions (BRDF / BTDF) are used to quantify the angle resolved scattering properties. The data can be used as an input for optical engineering software just as FRED, ASAP, ZEMAX for stray light modeling. In addition, analyzing the scattered light can provide valuable information about the relevant imperfections. The presentation provides an overview of instrumentation for light scattering measurements at wavelengths ranging from the visible to the extreme ultraviolet and the infrared spectral regions. Examples of applications will be discussed ranging from superpolished mirrors to diffraction gratings, interference coatings, and black absorbing coatings.

  7. Application of light scattering in studies of transport, thermodynamics, light absorption, and electric properties of single droplets

    NASA Astrophysics Data System (ADS)

    Tu, Haohua

    2001-12-01

    A variety of subjects related to an isolated microdroplet, including precise optical measurement, fundamental light scattering theory, in situ droplet spectroscopy, transport mechanism, solution thermodynamics, and electrical stability, have been studied. A technique based on optical resonance alignment is developed to automate the measurement of the optical parameters for a single component droplet. The technique is able to determine the size and refractive index of the droplet with an accuracy of 1 part in 10000, and is also applicable to multicomponent droplets undergoing various physical changes with tolerable degradation of accuracy or automation. By examining the finest details of optical resonances, Mie's light scattering theory is proved to be valid except for a constant background broadening deviation. The effect of eccentricity on light scattering of a layered droplet is first observed. By preparing a concentrically layered droplet, rigorous experimental verification is presented for Aden-Kerker light scattering theory of a concentric sphere. Novel computational technique is developed to identify optical resonances and locate their positions for a concentric sphere of specific properties. A unique technique based on accurate measurement of the imaginary refractive index of a droplet is developed for in situ determination of the concentrations of absorptive chemical species inside the droplet. The effects of Stefan flow, non-isothermal effect, unsteady state behavior, unstationary mechanism, and internal transport on the function of droplet size versus time of a relatively nonvolatile droplet have been proved unimportant. Remarkable accuracy of the asymptotic model based on Maxwell's diffusion controlled theory is justified both theoretically and experimentally. Particular evaporation characteristics are observed for several layered droplets. Explicit as well as implicit methods based on resonance alignment have been developed to determine the activity

  8. 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.

  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. 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.

  11. Light-Scattering Characteristics of Optical Surfaces

    DTIC Science & Technology

    1975-01-01

    UNCLASSIFIED Psd) Accession For NTIS GRA&I DTIC TAB Unannounced d ] Justificatio By - Distributon/_ Availability Codes JAvail and/or_ CHAPTER 1...rejection systems, evaluation of machined metal mirrors for high- energy laser applications , laser-radar backscatter signature programs, and a host of...other applications requiring extensive scattering data. If the scattering mechanism were completely understood, surface prepa- ration techniques or

  12. 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

  13. 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

  14. Investigation of the effect of scattering agent and scattering albedo on modulated light propagation in water.

    PubMed

    Mullen, Linda; Alley, Derek; Cochenour, Brandon

    2011-04-01

    A recent paper described experiments completed to study the effect of scattering on the propagation of modulated light in laboratory tank water [Appl. Opt.48, 2607 (2009)APOPAI0003-693510.1364/AO.48.002607]. Those measurements were limited to a specific scattering agent (Maalox antacid) with a fixed scattering albedo (0.95). The purpose of this paper is to study the effects of different scattering agents and scattering albedos on modulated light propagation in water. The results show that the scattering albedo affects the number of attenuation lengths that the modulated optical signal propagates without distortion, while the type of scattering agent affects the degree to which the modulation is distorted with increasing attenuation length.

  15. 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.

  16. 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

  17. Modelling of classical ghost images obtained using scattered light

    NASA Astrophysics Data System (ADS)

    Crosby, S.; Castelletto, S.; Aruldoss, C.; Scholten, R. E.; Roberts, A.

    2007-08-01

    The images obtained in ghost imaging with pseudo-thermal light sources are highly dependent on the spatial coherence properties of the incident light. Pseudo-thermal light is often created by reducing the coherence length of a coherent source by passing it through a turbid mixture of scattering spheres. We describe a model for simulating ghost images obtained with such partially coherent light, using a wave-transport model to calculate the influence of the scattering on initially coherent light. The model is able to predict important properties of the pseudo-thermal source, such as the coherence length and the amplitude of the residual unscattered component of the light which influence the resolution and visibility of the final ghost image. We show that the residual ballistic component introduces an additional background in the reconstructed image, and the spatial resolution obtainable depends on the size of the scattering spheres.

  18. Selective scattering polymer dispersed liquid crystal film for light enhancement of organic light emitting diode.

    PubMed

    Jiang, Jinghua; McGraw, Greg; Ma, Ruiqing; Brown, Julie; Yang, Deng-Ke

    2017-02-20

    We developed a novel light enhancing film for an organic light emitting diode (OLED) based on polymer dispersed liquid crystal (PDLC). In the film, the liquid crystal droplets are unidirectionally aligned along the film normal direction and exhibit selective scattering. The film scatters light emitted only in directions with large incident angles but not light emitted in directions with small incident angles. When the light is scattered, it changes propagation direction and exits the OLED. The PDLC film reduces the total internal reflection and thus can significantly increase the light efficiency of the OLED.

  19. A light-scattering characterization of membrane vesicles.

    PubMed Central

    Selser, J C; Yeh, Y; Baskin, R J

    1976-01-01

    A technique has been developed in this paper which enables quasi-elastic laser light scattering to be used to accurately and quantitatively measure the average vesicle diffusion coefficient and the relative dispersion in the diffusion coefficient about this average for dilute polydisperse vesicle suspensions. This technique relies on a theoretical analysis of a modified form of the Z-averaged diffusion coefficient. This modified Z-averaged diffusion coefficient explicitly incorporates vesicle size, structure, and polydispersity in a description of the scattered light autocorrelation spectrum. Light-scattering experiments were performed on a dilute, lobster sarcoplasmic reticulum vesicle suspension and the measured average diffusion coefficient and the diffusion coefficient relative dispersion about this average were determined with accuracies of 2 and 10%, respectively. A comparison of vesicle size inferred from light-scattering results was made with size results from electron microscopic analysis of the same sample. Images FIGURE 2 FIGURE 3 FIGURE 4 PMID:1252585

  20. Propagation and scattering of light in fluctuating media

    NASA Astrophysics Data System (ADS)

    Kuz'min, V. L.; Romanov, V. P.; Zubkov, L. A.

    1994-11-01

    The monograph deals with the problems of the propagation and scattering of light in molecular media. The explicit statistical mechanical averaging procedure for the equations of electrodynamics is developed. It permits to transform the molecular level description into the macroscopic one for the electrodynamics of the fluctuating media. In the framework of such an approach, the problems of the molecular correlation contribution into the dielectric permeability, of the calculation of the reflection coefficients with an account of surface layers and of the multiple light scattering are considered. The developed theory is applied to the description of the critical opalescence, the coherent backscattering enhancement, the light scattering depolarization phenomena and the propagation and scattering of light in anisotropic media, including the case of liquid crystals.

  1. Quasi-elastic light-scattering spectra of swimming spermatozoa. Rotational and translational effects.

    PubMed Central

    Craig, T; Hallett, F R; Nickel, B

    1979-01-01

    The electric field autocorrelation functions of light scattered from normal swimming bull spermatozoa are shown to be dependent on the mean head rotation frequency and not on the translational speed of the cells, as previously believed. This result was obtained from numerical generation of functions in which spermatozoa were modeled as Rayleigh-Gans-Debye ellipsoids having semiaxes a = 0.5 micrometer, b = 2.3 micrometer, and c = 9.0 micrometer. The magnitude of c required to achieve agreement with the experimental data is larger than the half-length of the head region of the cell. This implies that the midpiece, which also lies along c, contributes to the scattering power. Details regarding swimming trajectory and head orientation are included in the model. Analyses of the calculated functions and comparisons with experimentally determined ones suggest that at a scattering angle of 15 degrees the electric field autocorrelation function can be fit a simple Lorentzian whose half-width is inversely proportional to the scattering vector and the mean head rotational frequency. PMID:262561

  2. Experimental validation of light scattering and absorption theories of fractal-like carbonaceous aerosol agglomerates

    NASA Astrophysics Data System (ADS)

    Chakrabarty, R.; Moosmuller, H.; Arnott, W. P.; Garro, M.; Slowik, J.; Cross, E.; Han, J.; Davidovits, P.; Onasch, T.; Worsnop, D.

    2007-12-01

    The optical coefficients of size-selected carbonaceous aerosol agglomerates measured at a wavelength of 870 nm are compared with those predicted by three theories, namely Rayleigh-Debye-Gans (RDG) approximation, volume-equivalent Mie theory, and integral equation formulation for scattering (IEFS). Carbonaceous agglomerates, produced via flame synthesis, were size-selected using two differential mobility analyzers (DMAs) in series, and their scattering and absorption coefficients were measured with nephelometry and photoacoustic spectroscopy. Scanning electron microscopy, along with image processing techniques, were used for the parameterization of the structural properties of the fractal-like agglomerates. The agglomerate structural parameters were used to evaluate the predictions of the optical coefficients based on the three light scattering and absorption theories. The results indicate that the RDG approximation agrees within 10% of the experimental results and the exact electromagnetic calculations of the IEFS theory. The experimental scattering coefficient is over predicted by the volume-equivalent Mie theory by a factor of ~3.2. Also, the RDG approximation-predicted optical coefficients showed pronounced sensitivity to changes in monomer mean diameter, the count median diameter of the agglomerates, and the geometric standard deviation of the agglomerate number size distribution.

  3. Light scattering and absorption by fractal-like carbonaceous chain aggregates: comparison of theories and experiment

    NASA Astrophysics Data System (ADS)

    Chakrabarty, Rajan K.; Moosmüller, Hans; Arnott, W. Patrick; Garro, Mark A.; Slowik, Jay G.; Cross, Eben S.; Han, Jeong-Ho; Davidovits, Paul; Onasch, Timothy B.; Worsnop, Douglas R.

    2007-10-01

    This study compares the optical coefficients of size-selected soot particles measured at a wavelength of 870 nm with those predicted by three theories, namely, Rayleigh-Debye-Gans (RDG) approximation, volume-equivalent Mie theory, and integral equation formulation for scattering (IEFS). Soot particles, produced by a premixed ethene flame, were size-selected using two differential mobility analyzers in series, and their scattering and absorption coefficients were measured with nephelometry and photoacoustic spectroscopy. Scanning electron microscopy and image processing techniques were used for the parameterization of the structural properties of the fractal-like soot aggregates. The aggregate structural parameters were used to evaluate the predictions of the optical coefficients based on the three light-scattering and absorption theories. Our results show that the RDG approximation agrees within 10% with the experimental results and the exact electromagnetic calculations of the IEFS theory. Volume-equivalent Mie theory overpredicts the experimental scattering coefficient by a factor of ˜3.2. The optical coefficients predicted by the RDG approximation showed pronounced sensitivity to changes in monomer mean diameter, the count median diameter of the aggregates, and the geometric standard deviation of the aggregate number size distribution.

  4. 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.

  5. 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.

  6. Nonlinear light scattering by a dipole monolayer

    NASA Astrophysics Data System (ADS)

    Averbukh, B. B.; Averbukh, I. B.

    2013-08-01

    Scattering of a strong p-polarized monochromatic field by a dipole monolayer is considered. It is shown that a triplet should be observed at incident angles (between the wave vector of the incident wave and the normal to the monolayer surface) not too close to π/2 in the spectrum of the scattered radiation. For grazing incidence of a strong field on the monolayer, waves with frequencies of the strong field and the high-frequency component of the triplet scatter forward and backward. In this case, radiation with frequency of the low-frequency component of the triplet propagates in the form of two inhomogeneous waves along the monolayer on both sides of it, exponentially decaying with distance from the monolayer.

  7. Light scattering from Sickle Cell Hemoglobin: Polarized and Unpolarized

    NASA Astrophysics Data System (ADS)

    Chen, Kejing; Hantgan, Roy R.; Kim-Shapiro, Daniel B.

    1999-11-01

    Sickle cell polymers form due to aggregation of a mutant form of hemoglobin (HbS). The polymerization of HbS leads to microvascular occlusion characteristic of Sickle Cell Disease. A good understanding of HbS polymerization requires a way to quantify the degree of polymerization. As our calculations show, total intensity light scattering is not always linearly dependent on the amount of polymer. Polarized light scattering has been proposed as a more accurate way to measure polymer content. We use a new modulation method to measure all 16 Mueller Matrix elements, which completely describe how the Polarization State of light is altered upon scattering. Preliminary results of light scattering measurements from spheres and hemoglobin show that the instrument works properly. In future experiments, we will attempt to use polarized light scattering as an accurate measure of polymerization. In addition, Polarized light scattering may provide information on the higher order structure of sickle polymer bundles that has not been obtainable by other means.

  8. Scattering of light by bispheres with touching and separated components.

    PubMed

    Mishchenko, M I; Mackowski, D W; Travis, L D

    1995-07-20

    We use the T-matrix method as described by Mishchenko and Mackowski [Opt. Lett. 19, 1604 (1994)] to compute light scattering by bispheres in fixed and random orientations extensively. For all our computations the index of refraction is fixed at a value 1.5 + 0.005i, which is close to the refractive index of mineral tropospheric aerosols and was used in previous extensive studies of light scattering by spheroids and Chebyshev particles. For monodisperse bispheres with touching components in a fixed orientation, electromagnetic interactions between the constituent spheres result in a considerably more complicated interference structure in the scattering patterns than that for single monodisperse spheres. However, this increased structure is largely washed out by orientational averaging and results in scattering patterns for randomly oriented bispheres that are close to those for single spheres with size equal to the size of the bisphere components. Unlike other nonspherical particles such as cubes and spheroids, randomly oriented bispheres do not exhibit pronounced enhancement of side scattering and reduction of backscattering and positive polarization at side-scattering angles. Thus the dominant feature of light scattering by randomly oriented bispheres is the single scattering from the component spheres, whereas the effects of cooperative scattering and concavity of the bisphere shape play a minor role. The only distinct manifestations of nonsphericity and cooperative scattering effects for randomly oriented bispheres are the departure of the ratio F(22)/F(11) of the elements of the scattering matrix from unity, the inequality of the ratios F(33)/F(11) and F(44)/F(11), and nonzero linear and circular backscattering depolarization ratios. Our computations for randomly oriented bispheres with separated wavelengthsized components show that the component spheres become essentially independent scatterers at as small a distance between their centers as 4 times their

  9. Properties of the solid-liquid interface of growing salol crystals: A dynamic light scattering investigation

    NASA Astrophysics Data System (ADS)

    Dürig, U.; Bilgram, J. H.; Känzig, W.

    1984-08-01

    The freezing process has been studied by means of quasielastic light scattering at the solid-liquid interface of growing salol crystals. In the range of the investigated growth velocities, 0.2 μms<=vk<=0.8 μms, we observe two different dynamical processes at the interface, which can be distinguished by the scattered light. In a first process intense Rayleigh scattering sets in if a critical growth velocity is exceeded, which for growth along the [010] axis is in the range of 0.2 μms<=vcrit<=0.8 μms. Intensity measurements suggest that the scattering arises from fluctuations in an interface layer of a thickness of the order of 1μm. The spectrum of the scattered light can be fitted by a single Lorenzian with a linewidth Γ=Diq2 (q--> is the scattering vector). The thus obtained value of the diffusion constant, Di=(1.0+/-0.25)×10-9 cm2 s-1, is by 6 orders of magnitude smaller than the thermal diffusivity of liquid salol. In a second process the light is scattered by a propagating line-grating-like structure, which we interpret in terms of almost equidistant steps of growth spirals originating at screw dislocations. The step spacing d was determined from the angular distribution of the scattered intensity, and the step velocity vs from the Doppler shift. For a growth velocity vk=0.5 μm/s perpendicular to the (001) facet typical values are d=0.4 μm and vs=40 μm/s. For the step height h=vkdvs we obtain values of the order of 2.5 lattice constants. The product vsd is independent of vk and has a value of (1.8+/-0.4)×10-7 cm2 s-1, whereas vs is proportional to the square root of vk. An interpretation of the data is presented.

  10. Determination of wood grain direction from laser light scattering pattern

    NASA Astrophysics Data System (ADS)

    Simonaho, Simo-Pekka; Palviainen, Jari; Tolonen, Yrjö; Silvennoinen, Raimo

    2004-01-01

    Laser light scattering patterns from the grains of wood are investigated in detail to gain information about the characteristics of scattering patterns related to the direction of the grains. For this purpose, wood samples of Scots pine ( Pinus sylvestris L.) and silver birch ( Betula pubescens) were investigated. The orientation and shape of the scattering pattern of laser light in wood was found to correlate well with the direction of grain angles in a three-dimensional domain. The proposed method was also experimentally verified.

  11. 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.

  12. 2D light scattering label-free cytometry using light-sheet illumination

    NASA Astrophysics Data System (ADS)

    Lin, Meiai; Su, Xuantao

    2016-10-01

    Two-dimensional (2D) light scattering cytometry has been demonstrated as an effective label-free technology for cell analysis. Here we develop the light-sheet illumination in 2D light scattering static cytometry. In our cytometer, a cylindrical lens is used to form the light-sheet for better excitation of the static cells under an inverted microscope. The thickness of the light-sheet measured in fluorescent solution is about 13 μm. Two-dimensional light scattering patterns of standard microspheres and yeast cells are obtained by using a complementary metal oxide semiconductor (CMOS) detector via a low numerical aperture (NA 0.4) optical objective. The experimental patterns characterized with fringe structures agree well with Mie theory simulated ones. Our results suggest that the light-sheet illumination is an effective excitation method for 2D light scattering label-free cytometry.

  13. 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.

  14. Light scattering by surface acoustic waves on corrugated metal surfaces

    SciTech Connect

    Robertson, W.M.; Grimsditch, M. ); Moretti, A.L.; Kaufman, R.G.; Hulse, G.R. ); Fullerton, E.; Schuller, I.K. )

    1990-03-15

    We report the results of a Brillouin-scattering study of corrugated Ag surfaces. The corrugation plays a dramatic role in the wave-vector--selection rules governing coupling to surface phonons, and this effect is substantially different when the effective wave vector of the surface corrugation is collinear or perpendicular to the scattering plane. In processes that involve the grating wave vector, we show that the coupling mechanism between light and phonons is governed by surface plasmons which introduce a new scattering interaction with unusual polarization features in the Brillouin-scattering process.

  15. Light scattering modeling of bacteria using spheroids and cylinders

    NASA Astrophysics Data System (ADS)

    Feng, Chunxia; Huang, Lihua; Han, Jie; Zhou, Guangchao; Zeng, Aijun; Zhao, Yongkai; Huang, Huijie

    2009-11-01

    Numerical simulations of light scattering by irregularly shaped bacteria are carried out using the T-matrix method. A previously developed T-matrix code for the study of light scattering by randomly oriented non-spherical particles is used for the current purpose and it is validated against Mie-theory using coccus. Simplified particle shapes of spheroids and cylinders for simulating scattering by irregularly shaped bacteria are studied. The results for the angular distributions of the scattering matrix elements of B.Subtilis at wavelength 0.6328μm are presented. Their dependence on shape and model are discussed. Analysis suggests that spheroids perform better than cylinders for B.Subtilis. Calculations of the scatter matrix elements to determine bacteria sizes as well as shapes may be an accurate method and may be used to determine what the bacteria are.

  16. Decreasing Brillouin and Raman scattering by alternating-polarization light

    NASA Astrophysics Data System (ADS)

    Liu, Z. J.; Zheng, C. Y.; Cao, L. H.; Li, B.; Xiang, J.; Hao, L.

    2017-03-01

    A new method to reduce the scattering levels of stimulated Raman scattering (SRS) and stimulated Brillouin (SBS) scattering is proposed using alternating-polarization light. The effect of the new technique is related to the alternating time. If the alternating time is smaller than the growth time, the scattering level of SRS or SBS can be decreased. The SBS process is simulated by the fluid method, and the SRS process is verified by the particle-in-cell method. This method is also compared with the spike trains of uneven duration and delay (STUD) technique. Combining STUD pulses with alternating-polarization light is also discussed. Under proper alternating-polarization parameters, the scattering level of SRS and SBS can be dramatically reduced by more than one order of magnitude.

  17. 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.

  18. Experimental studies of laser light scattering in turbid media

    NASA Astrophysics Data System (ADS)

    Campbell, Sawyer; Grobe, Rainer; Su, Charles

    2006-05-01

    We inject an angularly collimated laser beam into a scattering medium of a non-dairy creamer-water solution and examine the distribution of the scattered light along the optical axis as a function of the source-detector spacing. The experimental and simulated data obtained from a Monte Carlo simulation on the optical axis suggest four regimes characterizing the transition from un-scattered to diffusive light. We compare the data with theoretical predictions based on a first-order scattering theory for regions close to the source, and with diffusion-like theories for larger source-detector spacings. We comment on the impact of the measurement on the light distribution and show that the regime of validity of these theories can depend on the experimental parameters such as the diameter and acceptance angle of the detection fiber.

  19. 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)

  20. 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....

  1. Light scattering in optical CT scanning of Presage dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Adamovics, J.; Cheeseborough, J. C.; Chao, K. S.; Wuu, C. S.

    2010-11-01

    The intensity of the scattered light from the Presage dosimeters was measured using a Thorlabs PM100D optical power meter (Thorlabs Inc, Newton, NJ) with an optical sensor of 1 mm diameter sensitive area. Five Presage dosimeters were made as cylinders of 15.2 cm, 10 cm, 4 cm diameters and irradiated with 6 MV photons using a Varian Clinac 2100EX. Each dosimeter was put into the scanning tank of an OCTOPUS" optical CT scanner (MGS Research Inc, Madison, CT) filled with a refractive index matching liquid. A laser diode was positioned at one side of the water tank to generate a stationary laser beam of 0.8 mm width. On the other side of the tank, an in-house manufactured positioning system was used to move the optical sensor in the direction perpendicular to the outgoing laser beam from the dosimeters at an increment of 1 mm. The amount of scattered photons was found to be more than 1% of the primary light signal within 2 mm from the laser beam but decreases sharply with increasing off-axis distance. The intensity of the scattered light increases with increasing light attenuations and/or absorptions in the dosimeters. The scattered light at the same off-axis distance was weaker for dosimeters of larger diameters and for larger detector-to-dosimeter distances. Methods for minimizing the effect of the light scattering in different types of optical CT scanners are discussed.

  2. 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.

  3. 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.

  4. Modeling of light scattering from features on and within films and light scatter from epitaxial silicon defects

    NASA Astrophysics Data System (ADS)

    Zhang, Haiping

    The detection of particles and defects on or within films deposited on wafers using light scattering is of great interest to the semiconductor industry. Numerical calculation of light scattering characteristics from these features is very useful to the development and calibration of wafer inspection tools. A model and associated code is developed by using a modification of the discrete-dipole approximation (DDA) method to compute the light scattering from a feature with arbitrary shape on or within a filmed surface. The reflection interaction matrix is modified with the Sommerfeld integrals for filmed surfaces. Three-dimensional fast Fourier transform technique is used for accelerating the computation of light scatter from features associated with layered surfaces using the DDA method. Far field scatter is calculated approximately based on the reaction theorem. Model predictions of scattering signatures are compared with experimental results and other numerical models. Comparisons show good agreement for the cases considered, which demonstrates the accuracy and validity of the model. An epitaxial silicon wafer defect sample was fabricated containing typical epitaxial wafer defects such as epitaxial stacking faults, spikes and mounds. Atomic force microscopy was used to determine their physical sizes and shapes. The optical scattering characteristics of these epitaxial silicon wafer defects were studied using the numerical model. A method to discriminate epitaxial crystalline defects and particles is proposed.

  5. 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.

  6. Hybrid graphene nematic liquid crystal light scattering device

    NASA Astrophysics Data System (ADS)

    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.

    2015-08-01

    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.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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04094a

  7. 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.

  8. 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.

    PubMed

    Thakkar, Disha; Gevriya, Bhavesh; Mashru, R C

    2014-03-25

    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/538nm, 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(2(4)) 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.

  9. 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

  10. 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

  11. Simulation model of scattering properties and extinction of laser light applied to urban aerosols over the city of Cali, Colombia

    NASA Astrophysics Data System (ADS)

    Rodríguez, Edith; Montilla, Elena; Jaramillo, Mauricio; Solarte, Efraín; Bastidas, Alvaro

    2005-10-01

    Aerosols are among the most spatially variable components of the atmosphere, and thus their study requires their monitoring over a broad geographic range. The backscattering of light from suspended solid and liquid particles in the atmosphere obeys Mie scattering theory. Light attenuation in the spectral region from 300 to 4000 nm due to Mie scattering exceeds that due to molecular (Rayleigh) scattering and ozone absorption combined. This occurs despite the fact that aerosol particle concentrations in the atmosphere are many orders of magnitude smaller than molecular concentrations. Starting from the characteristics of urban aerosols measured over the city of Cali (Colombia), 3° 30' N, 76° 30' W, with a PM10 particle selector, along with information on meteorological conditions typical of the region, we present the results of a study of light scattering properties generated using a model applied Mie scattering theory to size parameter between 0 and 50, with an increment of 0.01, and Matlab computer code, to simulate and predict measurements with a Lidar system operating at 532 nm.

  12. Light fields in complex media: Mesoscopic scattering meets wave control

    NASA Astrophysics Data System (ADS)

    Rotter, Stefan; Gigan, Sylvain

    2017-01-01

    The newly emerging field of wave front shaping in complex media has recently seen enormous progress. The driving force behind these advances has been the experimental accessibility of the information stored in the scattering matrix of a disordered medium, which can nowadays routinely be exploited to focus light as well as to image or to transmit information even across highly turbid scattering samples. An overview of these new techniques, their experimental implementations, and the underlying theoretical concepts following from mesoscopic scattering theory is provided. In particular, the intimate connections between quantum transport phenomena and the scattering of light fields in disordered media, which can both be described by the same theoretical concepts, are highlighted. Particular emphasis is put on how these topics relate to application-oriented research fields such as optical imaging, sensing, and communication.

  13. 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.

  14. 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.

  15. Surface Roughness Metrology By Angular Distributions Of Scattered Light

    NASA Astrophysics Data System (ADS)

    Gilsinn, David E.; Vorburger, Theodore V.; Teague, E. Clayton; MeLay, Michael J.; Giauque, Charles; Scire, Fredric E.

    1985-09-01

    On-line industrial inspection of batch manufactured parts requires fast measurement techniques for surface finish quality. In order to develop the measurement basis for these techniques, a system has been built to determine surface roughness by measuring the angular distributions of scattered light. The system incorporates data gathered from the angular distribution instrument and traditional surface stylus instruments. These data are used both as input and as comparison data in order to test various mathematical models of optical scattering phenomena. The object is to develop a mathematical model that uses the angular distribution of scattered light to deduce surface roughness parameters such as Ra and surface wavelength. This paper describes the results of an experiment in which angular scattered data from surfaces with sinusoidal profiles was used to compute the surface R and wavelength. Stylus measurements of these parameters were made separately. A comparative table is given of the computed and measured values. Estimates of uncertainties are also given.

  16. Osmotic virial coefficients for model protein and colloidal solutions: importance of ensemble constraints in the analysis of light scattering data.

    PubMed

    Siderius, Daniel W; Krekelberg, William P; Roberts, Christopher J; Shen, Vincent K

    2012-05-07

    Protein-protein interactions in solution may be quantified by the osmotic second virial coefficient (OSVC), which can be measured by various experimental techniques including light scattering. Analysis of Rayleigh light scattering measurements from such experiments requires identification of a scattering volume and the thermodynamic constraints imposed on that volume, i.e., the statistical mechanical ensemble in which light scattering occurs. Depending on the set of constraints imposed on the scattering volume, one can obtain either an apparent OSVC, A(2,app), or the true thermodynamic OSVC, B(22)(osm), that is rigorously defined in solution theory [M. A. Blanco, E. Sahin, Y. Li, and C. J. Roberts, J. Chem. Phys. 134, 225103 (2011)]. However, it is unclear to what extent A(2,app) and B(22)(osm) differ, which may have implications on the physical interpretation of OSVC measurements from light scattering experiments. In this paper, we use the multicomponent hard-sphere model and a well-known equation of state to directly compare A(2,app) and B(22)(osm). Our results from the hard-sphere equation of state indicate that A(2,app) underestimates B(22)(osm), but in a systematic manner that may be explained using fundamental thermodynamic expressions for the two OSVCs. The difference between A(2,app) and B(22)(osm) may be quantitatively significant, but may also be obscured in experimental application by statistical uncertainty or non-steric interactions. Consequently, the two OSVCs that arise in the analysis of light scattering measurements do formally differ, but in a manner that may not be detectable in actual application.

  17. Osmotic virial coefficients for model protein and colloidal solutions: Importance of ensemble constraints in the analysis of light scattering data

    NASA Astrophysics Data System (ADS)

    Siderius, Daniel W.; Krekelberg, William P.; Roberts, Christopher J.; Shen, Vincent K.

    2012-05-01

    Protein-protein interactions in solution may be quantified by the osmotic second virial coefficient (OSVC), which can be measured by various experimental techniques including light scattering. Analysis of Rayleigh light scattering measurements from such experiments requires identification of a scattering volume and the thermodynamic constraints imposed on that volume, i.e., the statistical mechanical ensemble in which light scattering occurs. Depending on the set of constraints imposed on the scattering volume, one can obtain either an apparent OSVC, A2,app, or the true thermodynamic OSVC, {B_{22}^{osm}}, that is rigorously defined in solution theory [M. A. Blanco, E. Sahin, Y. Li, and C. J. Roberts, J. Chem. Phys. 134, 225103 (2011), 10.1063/1.3596726]. However, it is unclear to what extent A2,app and {B_{22}^{osm}} differ, which may have implications on the physical interpretation of OSVC measurements from light scattering experiments. In this paper, we use the multicomponent hard-sphere model and a well-known equation of state to directly compare A2,app and {B_{22}^{osm}}. Our results from the hard-sphere equation of state indicate that A2,app underestimates {B_{22}^{osm}}, but in a systematic manner that may be explained using fundamental thermodynamic expressions for the two OSVCs. The difference between A2,app and {B_{22}^{osm}} may be quantitatively significant, but may also be obscured in experimental application by statistical uncertainty or non-steric interactions. Consequently, the two OSVCs that arise in the analysis of light scattering measurements do formally differ, but in a manner that may not be detectable in actual application.

  18. Light Scattering by Inhomogeneous Composite Particles.

    NASA Astrophysics Data System (ADS)

    Srivastava, Vandana

    The scattering characteristics of various composites is calculated using the effective medium approximations. There are several effective medium theories that can be applied, each leading to a different result. Experimentally, a set of scattering data for well defined composite spheres is obtained. The effective medium approximations are tested against the experimental results. The Bruggeman (1935) mixing rule and Maxwell Garnett (1904) theory, with proper inclusion and matrix model, lead to good agreement with the measurements. A generalized theory has also been derived (Chylek and Srivastava, 1983) which gives an iterative scheme for calculating the effective refractive index for composite medium. The Chylek-Srivastava iterative rule that takes into account all the electric and magnetic interactions for the absorbing component also leads to a good agreement with the measurements. This generalized theory can be applied to composites that contain a highly absorbing component with particle sizes comparable to the wavelength of incident radiation. Application of the Chylek-Srivastava iterative method to carbon-snow composites leads to calculated snow albedos that are in very good agreement with the measured albedos, eliminating the discrepancies that have existed for many years between calculated and measured albedos. Therefore, small amounts of absorbing impurities like carbon can significantly alter the scattering characteristics of composite particles. Carbon content of snow is also measured at different sites categorized as urban, rural, or remote, depending upon their location and elevation. The content varies according to the location of the site and the time of snow collection. However, ice from Camp Century, Greenland, that is several thousand years old contains the same order of graphitic carbon as does the remote polar surface snow at present. Backscattering of water-ice composites like hailstones depends upon the liquid water content and the topological

  19. 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.

  20. 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.

  1. Radiant intensity of light scattered from clouds.

    PubMed

    Plass, G N; Kattawar, G W

    1968-04-01

    A Monte Carlo method that accurately allows for the numerous small angle scattering events is used to calculate the reflected and transmitted radiance and flux of visible radiation that has interacted with cumulus clouds. The variation of these quantities with solar zenith angle, optical thickness of the cloud, and surface albedo is studied. When the surface albedo is zero, the reflected radiance has a relative maximum at the horizon (except for very thick clouds and incident beam near zenith). When the incident beam is near the horizon, there is a strong maximum in the reflected radiance on the solar horizon and a pronounced minimum near the zenith. There is a relative maximum in the transmitted radiance around the direction of the incident beam until the cloud becomes thick in that direction. In most instances, the variations are greatly decreased when the surface albedo is unity.

  2. Scattered light: improving photoacoustic spectral measurement with a drug tablet

    NASA Astrophysics Data System (ADS)

    Yu, Rong; Jiang, Yue-song; Yu, Lan; Wen, Dong-hai; Hua, Hou-qiang; Wu, Xiao-fang

    2013-08-01

    Photoacoustic spectroscopy (PAS) is a powerful tool for the study of the absorption spectra of solid samples. Scattered light, which used to be a main error source in conventional absorption spectroscopy, is not a problem for PAS, and furthermore, in this paper it is helpful for photoacoustic spectroscopy measurement. In this work, the photoacoustic spectra of an olanzapine tablet and its powder have been investigated. Differential analysis was used to eliminate the background signal generated by the photoacoustic cell. It is found that the photoacoustic spectrum of olanzapine in the powdered olanzapine tablet has the same spectral features as that of the pure olanzapine powder, while the photoacoustic spectrum of the olanzapine tablet does not have, although the ingredients in both are completely the same. This phenomenon can be interpreted as the light scattering effects in the powdered olanzapine tablet. The light scattering effects in a solid mixture amplify the photoacoustic spectral features of the main light-absorbing ingredient in the mixture, rather than enhance the measured photoacoustic signal over the whole measured wavelength range, which is different from the influence of light scattering effects on a single-ingredient solid powder. Based on this work, a method is proposed to preliminarily fast identify the light-absorbing ingredient in a solid mixture. Using the method, a drug tablet can be measured directly in solid state and hardly need sample preprocessing, and thus the time for composition analyses will be reduced significantly.

  3. Implementation of focusing and redirecting light through highly scattering media

    NASA Astrophysics Data System (ADS)

    Coyotl-Ocelotl, B.; Porras-Aguilar, R.; Ramos-Garcia, R.; Ramirez-San-Juan, J. C.

    2015-08-01

    Optical imaging through highly scattering media such as biological tissue is limited by light scattering. Recently, it has been shown that wavefront shaping is a powerful tool to overcome this problem. In this work, wavefront shaping using spatial light modulators is used to compensate static scattering media (piece of translucent tape) to allow focusing of different intensity distributions. Light propagation is engineered into a specific region of interest. For this purpose, a sequential phase shape algorithm was implemented experimentally. This algorithm is used to encode a phase distribution on an incident beam to pre-compensate phase distortions acquired by the beam after propagating through the tape. The sequential algorithm combined with a spatial light modulator is used to synthesize a phase distribution required for redirecting light using wavefront shaping. The scattered light was re-directed at the detector plane, in order to be: i) focused at a single pixel, ii) at squared regions of 3×3 and 5×5 pixeles and iii) a line pattern of 41 pixels of the camera. Furthermore, the region of interest was placed outside the central area of the camera opening the possibility of image formation.

  4. A Theory of Exoplanet Transits with Light Scattering

    NASA Astrophysics Data System (ADS)

    Robinson, Tyler D.

    2017-02-01

    Exoplanet transit spectroscopy enables the characterization of distant worlds, and will yield key results for NASA's James Webb Space Telescope. However, transit spectra models are often simplified, omitting potentially important processes like refraction and multiple scattering. While the former process has seen recent development, the effects of light multiple scattering on exoplanet transit spectra have received little attention. Here, we develop a detailed theory of exoplanet transit spectroscopy that extends to the full refracting and multiple scattering case. We explore the importance of scattering for planet-wide cloud layers, where the relevant parameters are the slant scattering optical depth, the scattering asymmetry parameter, and the angular size of the host star. The latter determines the size of the “target” for a photon that is back-mapped from an observer. We provide results that straightforwardly indicate the potential importance of multiple scattering for transit spectra. When the orbital distance is smaller than 10–20 times the stellar radius, multiple scattering effects for aerosols with asymmetry parameters larger than 0.8–0.9 can become significant. We provide examples of the impacts of cloud/haze multiple scattering on transit spectra of a hot Jupiter-like exoplanet. For cases with a forward and conservatively scattering cloud/haze, differences due to multiple scattering effects can exceed 200 ppm, but shrink to zero at wavelength ranges corresponding to strong gas absorption or when the slant optical depth of the cloud exceeds several tens. We conclude with a discussion of types of aerosols for which multiple scattering in transit spectra may be important.

  5. Static laser light scattering (SLLS) investigations of the scattering parameters of a synthetic polymer

    NASA Astrophysics Data System (ADS)

    Ghazy, R.; El-Baradie, B.; El-Shaer, A.; El-Mekawey, F.

    1999-09-01

    A laser light scattering system was built to study the scattering parameters of some materials in solution form. The light source used was an argon-ion laser at wavelength 488 nm (all lines). The investigated material was a synthetic polymer which has a wide range of applications in the field of teeth medicine applications. This is polymethyl-methacrylate (PMMA) which is used for the formation of artificial clamps. The PMMA was solved in both acetone and methyl-ethyl-ketone (MEK). The acetone solvent is chosen for its high specific refractive index increment dn/dc at the same wavelength 488 nm as the argon laser source. The angular distribution of the scattered laser light intensities of PMMA dissolved in acetone was measured at different scattering angles from 30 to 150° for each concentration. The angular distributions have a symmetrical behavior about the scattering angle π/2; by using the scattered intensities the Zimm plot was formed. The weight average molecular weight (WAMW) was determined, the two other scattering parameters like as radius of gyration, h, and the second verial coefficient, A2 were determined.

  6. 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.

  7. 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.

  8. Light scattering regimes along the optical axis in turbid media

    NASA Astrophysics Data System (ADS)

    Campbell, S. D.; O'Connell, A. K.; Menon, S.; Su, Q.; Grobe, R.

    2006-12-01

    We inject an angularly collimated laser beam into a scattering medium of a nondairy creamer-water solution and examine the distribution of the scattered light along the optical axis as a function of the source-detector spacing. The experimental and simulated data obtained from a Monte Carlo simulation suggest four regimes characterizing the transition from unscattered to diffusive light. We compare the data also with theoretical predictions based on a first-order scattering theory for regions close to the source, and with diffusionlike theories for larger source-detector spacings. We demonstrate the impact of the measurement process and the effect of the unavoidable absorption of photons by the detection fiber on the light distribution inside the medium. We show that the range of validity of these theories can depend on the experimental parameters such as the diameter and acceptance angle of the detection fiber.

  9. Light scattering regimes along the optical axis in turbid media.

    PubMed

    Campbell, S D; O'connell, A K; Menon, S; Su, Q; Grobe, R

    2006-12-01

    We inject an angularly collimated laser beam into a scattering medium of a nondairy creamer-water solution and examine the distribution of the scattered light along the optical axis as a function of the source-detector spacing. The experimental and simulated data obtained from a Monte Carlo simulation suggest four regimes characterizing the transition from unscattered to diffusive light. We compare the data also with theoretical predictions based on a first-order scattering theory for regions close to the source, and with diffusionlike theories for larger source-detector spacings. We demonstrate the impact of the measurement process and the effect of the unavoidable absorption of photons by the detection fiber on the light distribution inside the medium. We show that the range of validity of these theories can depend on the experimental parameters such as the diameter and acceptance angle of the detection fiber.

  10. Optical model of transient light scattering in ferroelectric liquid crystals

    SciTech Connect

    Loiko, V. A. Konkolovich, A. V.; Miskevich, A. A.

    2009-03-15

    A static optical model is developed for the effect of field-induced transient scattering on coherent light transmission through ferroelectric liquid crystals. Scattering processes are described by introducing an optically anisotropic medium containing scatterers (transient domains). The results presented in the paper are obtained for a plane parallel layer of ferroelectric liquid crystals with a planar helicoidal structure under normal illumination with a linearly polarized plane wave. An analysis is presented of the coherent transmittance of the layer in static applied electric fields.

  11. Dynamic Laser-Light Scattering Study on Bacterial Growth

    NASA Astrophysics Data System (ADS)

    Miike, Hidetoshi; Hideshima, Masao; Hashimoto, Hajime; Ebina, Yoshio

    1984-08-01

    The motility changes in growing bacteria in a culture medium were observed with a dynamic light-scattering technique used to analyse the frequency spectrum of the scattered light intensity. Two typical enterobacteriaceae, E. coil and P. morganii, were examined, and the change in the velocity distribution of the bacteria with time was analysed using the observed spectrum. The distribution pattern was found to change from a Gaussian-type to a Saclay-type with time, and the mean speed of the bacteria had a maximum value at around the turning point of the growth curve.

  12. Nonspherical nanoparticles characterization by partially depolarized dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Levin, Alexander D.; Shmytkova, Ekaterina A.

    2015-06-01

    The realization of improved depolarized dynamic light scattering method is presented. This technique supports measurement of non-spherical nanoparticals dimensions in liquids. The relations between translational and rotational diffusion coefficients and autocorrelation function of scattered light with polarized and depolarized components in various proportions are derived. Thus measurement of very weak cross-polarized component can be avoided. This improvement permits to reduce measurement time, to improve signal to noise ratio and results precision. The technique was applied for sizing of gold nanorods and multiwalled carbon nanotubes in liquids.

  13. Pressure injury prediction using diffusely scattered light

    NASA Astrophysics Data System (ADS)

    Diaz, David; Lafontant, Alec; Neidrauer, Michael; Weingarten, Michael S.; DiMaria-Ghalili, Rose Ann; Scruggs, Ericka; Rece, Julianne; Fried, Guy W.; Kuzmin, Vladimir L.; Zubkov, Leonid

    2017-02-01

    Pressure injuries (PIs) originate beneath the surface of the skin at the interface between bone and soft tissue. We used diffuse correlation spectroscopy (DCS) and diffuse near-infrared spectroscopy (DNIRS) to predict the development of PIs by measuring dermal and subcutaneous red cell motion and optical absorption and scattering properties in 11 spinal cord injury subjects with only nonbleachable redness in the sacrococcygeal area in a rehabilitation hospital and 20 healthy volunteers. A custom optical probe was developed to obtain continuous DCS and DNIRS data from sacrococcygeal tissue while the subjects were placed in supine and lateral positions to apply pressure from body weight and to release pressure, respectively. Rehabilitation patients were measured up to four times over a two-week period. Three rehabilitation patients developed open PIs (POs) within four weeks and eight patients did not (PNOs). Temporal correlation functions in the area of redness were significantly different (p<0.01) during both baseline and applied pressure stages for POs and PNOs. The results show that our optical method may be used for the early prediction of ulcer progression.

  14. Coherent anti-Stokes Raman scattering imaging under ambient light

    PubMed Central

    Zhang, Yinxin; Liao, Chien-Sheng; Hong, Weili; Huang, Kai-Chih; Yang, Huaidong; Jin, Guofan; Cheng, Ji-Xin

    2017-01-01

    We demonstrate ambient light coherent anti-Stokes Raman scattering (AL-CARS) microscopy that allows CARS imaging to be operated under environment light for field use. 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. Filters in both spectral domain and frequency domain effectively blocked room light contamination of the CARS image. In situ hyperspectral CARS imaging of tumor tissue under ambient light is demonstrated. PMID:27519113

  15. 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.

  16. 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.

  17. Polarized Light Scattering from Perfect and Perturbed Surfaces and Fundamental Scattering Systems

    DTIC Science & Technology

    1992-02-29

    Final Report 01 Mar 90 to 29 Feb 92 4. TITLE AND SUBTITLE 5...... . FUNDING NUMBERS" Polarized light scattering from perfect and perturbed surfaces...and fundamental scattering systems 6. AUTHOR(S) 2306/A3 Professor William S. Bickel 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) B. PERFORMING...NOTES J UL 19 9 2 12a. DISTRIBUTION AVAILABILITY STATEMENT • W ). DISTRIBUTION CODE APPROVED FOR PUBLIC RELEASE: DISTRIBUTION IS UNLIMITED 13

  18. Light-by-light scattering sum rules in light of new data

    NASA Astrophysics Data System (ADS)

    Danilkin, Igor; Vanderhaeghen, Marc

    2017-01-01

    We evaluate the light-quark meson contributions to three exact light-by-light scattering sum rules in light of new data by the Belle Collaboration, which recently has extracted the transition form factors of the tensor meson f2(1270 ) as well as of the scalar meson f0(980 ). We confirm a previous finding that the η ,η' and helicity-2 f2(1270 ) contributions saturate one of these sum rules up to photon virtualities around 1 Ge V2 . At larger virtualities, our sum rule analysis shows an important contribution of the f2(1565 ) meson and provides a first empirical extraction of its helicity-2 transition form factor. Two further sum rules allow us to predict the helicity-0 and helicity-1 transition form factors of the f2(1270 ) meson. Furthermore, our analysis also provides an update for the scalar and tensor meson hadronic light-by-light contributions to the muon's anomalous magnetic moment.

  19. 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.

  20. Influences of refractive index on forward light scattering

    NASA Astrophysics Data System (ADS)

    Han, Xueshan; Shen, Jianqi; Yin, Pengteng; Hu, Shiyu; Bi, Duo

    2014-04-01

    The influence of the relative refractive index (RRI) of the particles to the surrounding medium on the small-angle forward scattering signals is studied, based on the Mie theory, the Debye series expansion (DSE) and the Fraunhofer diffraction theory. It comes to the conclusion that, for small particles, the influence on the forward scattering signals is mainly due to the part of the internal reflection if the RRI deviates from 1. However, when the RRI is close to 1, the effects on the forward scattered light from both the surface reflection and the internal reflection are great. For large particles, the contributions of the surface reflection and the internal reflection to the forward scattered light are much weaker than the diffraction when the RRI deviates from 1. When the RRI is very close to 1, the effects on the forward scattered light from the internal reflection are great. To determine the influence of the RRI in detail, the modified Chahine algorithm is employed. The inversion results cannot give the correct PSD for small particles if the RRI used in the inversion procedure does not match the one of the sample. The result shows that it is necessary to determine the exact value of the RRI and one should avoid the RRI close to 1 by choosing dispersion with proper refractive index in practice.

  1. Development of bacterial colony phenotyping instrument using reflected scatter light

    NASA Astrophysics Data System (ADS)

    Doh, Iyll-Joon

    Bacterial rapid detection using optical scattering technology (BARDOT) involves in differentiating elastic scattering pattern of bacterial colony. This elastic light scatter technology has shown promising label-free classification rate. However, there is limited success in certain circumstances where either a growth media or a colony has higher opacity. This situation is due to the physical principles of the current BARDOT which mainly relies on optical patterns generated by transmitted signals. Incoming light is obstructed and cannot be transmitted through the dense bacterial colonies, such as Lactobacillus, Yeast, mold and soil bacteria. Moreover, a blood agar, widely used in clinical field, is an example of an opaque media that does not allow light to be transmitted through. Therefore, in this research, a newly designed reflection type scatterometer is presented. The reflection type scatterometer measures the elastic scattering pattern generated by reflected signal. A theoretical model to study the optical pattern characteristic with respect to bacterial colony morphology is presented. Both theoretical and experiment results show good agreement that the size of backward scattering pattern has positive correlation to colony aspect ratio, a colony elevation to diameter ratio. Four pathogenic bacteria on blood agar, Escherichia coli K12, Listeria innocua, Salmonella Typhimurium, and Staphylococcus aureus, are tested and measured with proposed instrument. The measured patterns are analyzed with a classification software, and high classification rate can be achieved.

  2. Monte carlo calculations of light scattering from clouds.

    PubMed

    Plass, G N; Kattawar, G W

    1968-03-01

    The scattering of visible light by clouds is calculated from an efficient Monte Carlo code which follows the multiple scattered path of the photon. The single scattering function is obtained from the Mie theory by integration over a particle size distribution appropriate for cumulus clouds at 0.7-micro wavelength. The photons are followed through a sufficient number of collisions and reflections from the lower surface (which may have any desired albedo) until they make a negligible contribution to the intensity. Various variance reduction techniques are used to improve the statistics. The cloud albedo and the mean optical path of the transmitted and reflected photons are given as a function of the solar zenith angle, optical thickness, and surface albedo. The numerous small angle scatterings of the photon in the direction of the incident beam are followed accurately and produce a greater penetration into the cloud than is obtained with a more isotropic and less realistic phase function.

  3. Effects of the mixture composition on the microstructure of polymer matrix and light scattering properties of liquid crystal/photo-polymerizable monomers composites

    NASA Astrophysics Data System (ADS)

    Li, Wenbo; Cheng, Zihui; Pan, Guohui; Liu, Huijing; Cao, Hui; Yang, Zhou; Yang, Huai

    2008-10-01

    The microstructure and electro-optical effects based on light scattering have been investigated for nematic liquid crystal (LC)/photo-polymerizable monomers composites. It was demonstrated that the optimum electro-optical properties of the composites were obtained when the LC content was between 60 and 70 wt%. Furthermore, the variety of the light scattering intensity for the composites in the wavelength region of 300-2500 nm was studied experimentally and theoretically with the combination of three kinds of classical light scattering theories: the Rayleigh-Gans (RG) approach, the anomalous diffraction (AD) approach, and the geometrical optics (GO) approach. Then a simple mathematic simulation was established to describe the relationship between the transmittance and the incident wavelength in this wavelength region.

  4. 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)

  5. A Study of Structural Phase Transitions Using Light Scattering Techniques.

    DTIC Science & Technology

    1981-12-01

    n.g (a" &"I* L TYPE OF REPORT a PERID COVER=o rinal Report, A Study of structural phase transitions using October 1981 light scattering tenchniques S...SWWJUTY CLPWICATION OP ThIS PAGE (VIM1- Sum • . i i - • .. . . . ’ ’ .... . . . ’ ’ ’ . . L .. .. . ’.. . Table of contents 1) Results Page (a

  6. Energy conservation - A test for scattering approximations

    NASA Technical Reports Server (NTRS)

    Acquista, C.; Holland, A. C.

    1980-01-01

    The roles of the extinction theorem and energy conservation in obtaining the scattering and absorption cross sections for several light scattering approximations are explored. It is shown that the Rayleigh, Rayleigh-Gans, anomalous diffraction, geometrical optics, and Shifrin approximations all lead to reasonable values of the cross sections, while the modified Mie approximation does not. Further examination of the modified Mie approximation for the ensembles of nonspherical particles reveals additional problems with that method.

  7. Experimental investigation of the nonlinear Rayleigh- Taylor instability in CH foils irradiated by UV light

    NASA Astrophysics Data System (ADS)

    Smalyuk, Vladimir A.

    1999-10-01

    In direct-drive inertial confinement fusion (ICF), nonuniformities in the laser drive can create (or imprint) mass perturbations in the target and seed hydro- dynamic instabilities. Understanding of this imprinting and the temporal evolution of resulting features is of utmost importance to high-gain target designs. Time- integrated optical measurements of a single OMEGA laser beam show that smoothing techniques such as distributed phase plates (DPP's) and smoothing by spectral dispersion (SSD) generate a broadband spectrum of laser nonuniformities. These nonuniformities are imprinted into targets, then, during a laser-driven acceleration, the Rayleigh-Taylor instability amplifies these features. The temporal evolution of these mass perturbations is studied using x-ray through-foil radiography of planar CH targets employing pinholes and framing cameras. To study these phenomena, it is important that the spatial response of the instrumentation be properly characterized. The noise in these experiments is limited by the photon statistics of the uranium backlighter x rays and the system resolution is limited by 8-μm pinhole. Using the measured system resolution, noise, and sensitivity, a Wiener filter has been constructed to filter the noise from the images and deconvolve the system MTF in order to recover the target's areal density modulations. The Fourier analysis of the radiographic images shows that the perturbations evolve to longer wavelengths and the amplitudes of the shorter wavelengths saturate. The saturation amplitudes and the rates of growth of these features are consistent with the predictions of Haan for broadband spectrum [1]. Using high-contrast, thin 5-μm teflon targets, the imprint has been measured at the time of the shock breakout using the same radiographic system.

  8. Banquet Speech Some Sketches Of Rayleigh

    NASA Astrophysics Data System (ADS)

    Howard, John N.

    1985-11-01

    Several short sketches are presented of Lord Rayleigh, to show his method of working and his interaction with his fellow scientists. The topics discussed are: his research on the blue of the sky (Rayleigh scattering); his rescue of Waterston from near-oblivion; his research on surface acoustic waves (Rayleigh waves); his collaboration with Agnes Pockels; his research on blackbody radiation (the Rayleigh-Jeans Law).

  9. Disordered Cellulose-Based Nanostructures for Enhanced Light Scattering

    PubMed Central

    2017-01-01

    Cellulose is the most abundant biopolymer on Earth. Cellulose fibers, such as the one extracted form cotton or woodpulp, have been used by humankind for hundreds of years to make textiles and paper. Here we show how, by engineering light–matter interaction, we can optimize light scattering using exclusively cellulose nanocrystals. The produced material is sustainable, biocompatible, and when compared to ordinary microfiber-based paper, it shows enhanced scattering strength (×4), yielding a transport mean free path as low as 3.5 μm in the visible light range. The experimental results are in a good agreement with the theoretical predictions obtained with a diffusive model for light propagation. PMID:28191920

  10. Multiple light scattering and absorption in reef-building corals.

    PubMed

    Terán, Emiliano; Méndez, Eugenio R; Enríquez, Susana; Iglesias-Prieto, Roberto

    2010-09-20

    We present an experimental and numerical study of the effects of multiple scattering on the optical properties of reef-building corals. For this, we propose a simplified optical model of the coral and describe in some detail methods for characterizing the coral skeleton and the layer containing the symbiotic algae. The model is used to study the absorption of light by the layer of tissue containing the microalgae by means of Monte Carlo simulations. The results show that, through scattering, the skeleton homogenizes and enhances the light environment in which the symbionts live. We also present results that illustrate the modification of the internal light environment when the corals loose symbionts or pigmentation.

  11. Functional Imaging of Tissue Morphology with Polarized Light Scattering Spectroscopy

    NASA Astrophysics Data System (ADS)

    Backman, Vadim

    2001-03-01

    We report a new imaging technique to study the morphology of living epithelial cells in vivo. The method is based on light scattering spectroscopy with polarized light (PLSS) and makes it possible to distinguish between single backscattering from epithelial cell nuclei and multiply scattered light. The spectrum of the single backscattering component is further analyzed to provide quantitative histological information about the epithelial cells such as the size distribution, refractive index, and chromatin content of the cell nuclei. The measurement of cell nuclear morphology is crucial for detection and diagnosis of cancerous and precancerous conditions in many human tissues. The method was successfully applied to image precancerous regions of several tissues. Clinical studies in five organs (esophagus, colon, bladder, oral cavity, and uterine cervix) showed the generality and efficacy of the technique.

  12. Probing dynamics at interfaces: resonance enhanced dynamic light scattering.

    PubMed

    Plum, Markus A; Steffen, Werner; Fytas, George; Knoll, Wolfgang; Menges, Bernhard

    2009-06-08

    Experiments addressing supramolecular dynamics at interfaces are of paramount importance for the understanding of the dynamic behaviour of polymers, particles, or cells at interfaces, transport phenomena to and from surfaces, thin films or membranes. However, there are only few reports in the literature due to the paucity of experimental methods that offer the required spatial and time resolution. Evanescent wave dynamic light scattering originally developed to meet these needs has limited sensitivity and is restricted to glass substrates. Here we report the first experimental realization of a dynamic light scattering experiment close to an interface using surface plasmon polaritons as light source offering a strong increase in the signal to noise ratio and allowing for the use of metallic interfaces. As a proof of concept, we consider the diffusion of particles with radii down to 10nm in dilute dispersions close to a gold surface.

  13. 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.

  14. Surface texture characterization by angular distributions of scattered light

    NASA Technical Reports Server (NTRS)

    Gilsinn, D. E.; Vorburger, T. V.; Scire, F. E.; Teague, E. C.; Mclay, M. J.

    1985-01-01

    Work at the National Bureau of Standards to develop an on-line optical measurement device and attendant algorithms for automated optical scattering measurements of machined metal surfaces are described. The surfaces could be milled, ground or lapped, and the system is intended to categorize the resulting surface characteristics. The optical device consists of a He-Ne laser which is shone on a surface. The scattered light is captured by a semicircular array of 87 detector elements rotated over the scanned area. The light signals are processed through a digital voltmeter and then an A/D converter. The signals are then stored for later comparisons with optical scattering data obtained by optical instruments used with stylus instruments for characterizing surface topographies. A theoretical model has been defined which relates light scattering and the characteristics of the surface roughness. Initial experimental results with a sinusoidal surface have indicated that although the system can follow the trend of the roughness, the roughness amplitude is as yet uncertainly defined and the computations require excessive time.

  15. Scattering of light by polydisperse, randomly oriented, finite circular cylinders.

    PubMed

    Mishchenko, M I; Travis, L D; Macke, A

    1996-08-20

    We use the T-matrix method, as described by Mishchenko [Appl. Opt. 32, 4652 (1993)], to compute rigorously light scattering by finite circular cylinders in random orientation. First we discuss numerical aspects of T -matrix computations specific for finite cylinders and present results of benchmark computations for a simple cylinder model. Then we report results of extensive computations for polydisperse, randomly oriented cylinders with a refractive index of 1.53 + 0.008i, diameter-to-length ratios of 1/2, 1/1.4, 1, 1.4, and 2, and effective size parameters ranging from 0 to 25. These computations parallel our recent study of light scattering by polydisperse, randomly oriented spheroids and are used to compare scattering properties of the two classes of simple convex particles. Despite the significant difference in shape between the two particle types (entirely smooth surface for spheroids and sharp rectangular edges for cylinders), the comparison shows rather small differences in the integral photometric characteristics (total optical cross sections, single-scattering albedo, and asymmetry parameter of the phase function) and the phase function. The general patterns of the other elements of the scattering matrix for cylinders and aspect-ratio-equivalent spheroids are also qualitatively similar, although noticeable quantitative differences can be found in some particular cases. In general, cylinders demonstrate much less shape dependence of the elements of the scattering matrix than do spheroids. Our computations show that, like spheroids and bispheres, cylinders with surface-equivalent radii smaller than a wavelength can strongly depolarize backscattered light, thus suggesting that backscattering depolarization for nonspherical particles cannot be universally explained by using only geometric-optics considerations.

  16. 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.

  17. Using neural networks for dynamic light scattering time series processing

    NASA Astrophysics Data System (ADS)

    Chicea, Dan

    2017-04-01

    A basic experiment to record dynamic light scattering (DLS) time series was assembled using basic components. The DLS time series processing using the Lorentzian function fit was considered as reference. A Neural Network was designed and trained using simulated frequency spectra for spherical particles in the range 0–350 nm, assumed to be scattering centers, and the neural network design and training procedure are described in detail. The neural network output accuracy was tested both on simulated and on experimental time series. The match with the DLS results, considered as reference, was good serving as a proof of concept for using neural networks in fast DLS time series processing.

  18. RBC aggregation effects on light scattering from blood

    NASA Astrophysics Data System (ADS)

    Shvartsman, Leonid D.; Fine, Ilya

    2000-11-01

    We consider a number of diffusive and transport models of light transmission through whole blood, targeting better understanding of nature of optical transmission pulsations for blood flow modulated by heartbeats. We claim the existence of scattering- associated mechanism rather than the absorption-associated one. Single erythrocytes and their aggregates are considered to be the main centers of scattering in the red- near infrared spectral region. The shape and size of aggregates change in time due to blood flow changes. The corresponding changes of optical transmission are simulated.

  19. Propagating light through a scattering medium with specific amplitude and phase (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Tseng, Snow H.; Kung, Te-Jen; Yu, Min-Lun

    2016-03-01

    By means of numerical solutions of Maxwell's equations, we model the complex light scattering phenomenon. Light propagation through scattering medium is a deterministic process; with specific amplitude and phase, light can propagate to the target position via multiple scattering. By means of numerical solutions of Maxwell's equations, the complex light scattering phenomenon can be accurately analyzed. The reported simulation enables qualitative and quantitative analyses of the effectiveness of directing light through turbid media to a targeted position

  20. Incorporation of flow injection analysis with dual-wavelength overlapping resonance Rayleigh scattering for rapid determination of malachite green and its metabolite in fish.

    PubMed

    Zhu, Jinghui; Qin, Mingyou; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli

    2014-09-15

    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. 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.

  2. Highly sensitive and selective determination of fluorine ion by graphene oxide/nanogold resonance Rayleigh scattering-energy transfer analytical platform.

    PubMed

    Liang, Aihui; Peng, Jing; Liu, Qingye; Wen, Guiqing; Lu, Zhujun; Jiang, Zhiliang

    2015-08-15

    In pH 4.0 acetate buffer solution, fluorine ions react with fluorine reagent (FR) and La(III) to generate blue ternary complex that exhibited strong absorption at about 370 nm. Upon addition of graphene oxide/nanogold (GO/NG) as resonance Rayleigh scattering (RRS) spectral probe with strong RRS peak at 370 nm, the color changed to gray, and the RRS intensity decreased with the increase of fluorine ion concentration due to the RRS energy transfer (RRSET) from GO/NG to the complex. Under the selected condition, the decreased RRS peak ΔI370 nm was linear to fluorine ion concentration in the range of 6.0 × 10(-8)-1.3 × 10(-5)mol/L, with a detection limit of 3.0 × 10(-8)mol/L F(-). This RRSET method was applied to the analysis of fluorine in toothpaste and water samples, with satisfactory results.

  3. Light scattering from impurity enhanced liquid layers in polycrystalline ice

    NASA Astrophysics Data System (ADS)

    Thomson, E. S.; Wettlaufer, J. S.; Wilen, L. A.

    2009-12-01

    Impurity enhanced grain boundary premelting underlies a wide range of geophysical phenomena throughout the cryosphere. In particular, it is known that when water droplets freeze in the atmosphere they are highly polycrystalline and impurities are rejected into grain boundaries. The predicted character and sensitivity of grain boundaries to impurities close to the melting point precludes the use of standard techniques for imaging the interface. Unlike their larger more macroscopic relatives such as veins (3 grain intersections) and nodes (4 grain intersections), grain boundaries do not submit to optical microscopy. However, using an experimental light scattering method grain boundary changes can be measured as a function of thermodynamic variables. Accurate analysis of the light scattering data generated using this method requires a full theory of light propagation through the grain boundary layer straddled by ice crystals. Here we present a theory for light scattering from such a boundary, experimental data using NaCl as a dopant, and dicsuss atmospheric implications from the troposphere to the stratosphere.

  4. 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

  5. Effects of (R)- and (S)-propranolol hydrochloride enantiomers on the resonance Rayleigh scattering spectra with erythrosine B as probe and their analytical applications.

    PubMed

    Yang, Jidong; Wang, Ernv; Zhou, Shang; Yang, Qiong

    2015-03-01

    Propranolol, a chiral drug with two configurations, i.e., (R)-propranolol hydrochloride (RPH) and (S)-propranolol hydrochloride (SPH), has racemes that can be used in clinical diagnosis due to their synergistic effects. SPH has a β-receptor blocking effect, and RPH has an antiarrhythmic effect. In pH 4.6 Britton-Robinson (BR) buffer solution, both RPH and SPH can react with erythrosine B to form 1:1 ion-association complexes. In the SPH-Ery B reaction system, a remarkable enhancement of the resonance Rayleigh scattering (RRS) signal located at 338 nm was observed. However, a similar phenomenon was not obvious and was unstable in the RPH-Ery B reaction system. Based on this result, a simple, novel and sensitive method for the determination of SPH was proposed based on the RRS technique. The linear range and limit of detection were 0.0680~4.0 µg mL(-1) and 20.6 ng mL(-1), respectively. Additionally, the spectroscopic approaches of frequency doubling scattering (FDS) and second-order scattering (SOS) were also proposed for SPH detection in this article. The interaction information regarding the mechanism of the reaction, suitable reaction conditions, influencing factors and the effects of mixed solutions were our investigation aims. The method had been applied to the determination of SPH in fresh serum and urine samples of healthy human subjects with satisfactory results.

  6. Simulations of light-light scattering in quantum vacuum

    NASA Astrophysics Data System (ADS)

    Carneiro, Pedro; Grismayer, Thomas; Silva, LuíS.; Fonseca, Ricardo

    2016-10-01

    Facilities such as the Extreme Light Infrastructure (ELI) or the VULCAN 20 PW project, as well as the Petta-Watt SLAC project, coupled with the x-ray LCLSII source will allow to perform the first experiments on the probing of quantum vacuum. In our work, we developed a numerical method to self-consistently solve the nonlinear system of Maxwell's equations including quantum corrections of vacuum polarization. The robustness of our algorithm allied to the ability to integrate this tool within a particle-in-cell (PIC) method, represents an important milestone in modeling future planned experiments to prove the existence of the quantum vacuum. Such experiments aim to measure the induced ellipticity on a x-ray pulse after probing a strong optical pump due to the quantum vacuum fluctuations. We present simulation results of both the ellipticity induced and polarization rotation, using realistic laser parameters of the Petta-Watt SLAC project, and the x-ray LCLSII source, whilst taking into account all finite-size multi-dimensional effects. We show how the ellipticity induced varies as a function of the distance to the axis of the beam, proving the importance of taking into account finite-size effects. This work serves as an important tool to complement existing efforts within the community to probe the effects of the quantum vacuum, in the strong field regime, for the first time.

  7. Orientation-preserving transfer and directional light scattering from individual light-bending nanoparticles.

    PubMed

    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.

  8. 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.

  9. 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.

  10. Light scattering from acoustic vibrational modes in confined structures

    NASA Astrophysics Data System (ADS)

    Bandhu, Rudra Shyam

    The acoustic vibrational modes and their light scattering intensities in confined structures such as supported films, double layer free-standing membrane and sub-micron sized wires on a free-standing membrane have been studied using Brillouin Light Scattering (BLS). Standing wave type acoustic phonons were recently observed in supported thin films of silicon oxy-nitride. We build upon this finding to study the acoustic modes in thin zinc selenide (ZnSe) films on gallium arsenide (GaAs). The surprising behaviour of the Brillouin intensities of the standing wave modes in ZnSe are explained in terms of interference of the elasto-optic scattering amplitudes from the film and substrate. Numerical calculations of the scattering cross-section, which takes into account ripple and elasto-optic scattering mechanism, agrees well with the experimental data. Light scattering studies of standing wave type modes in free-standing polymethyl methacrylate (PMMA) layer on Si3N4 were carried out. In these bilayer structures PMMA is much softer than Si3N 4, a property that leads to confinement of low frequency modes associated with the PMMA layer to within its boundaries. In addition, the flexural and the dilatational modes from the Si3N4 layer are observed and are found to hybridize with the standing wave modes from the PMMA layer. Our study of phonon modes in PMMA wires supported on a free-standing Si3N4 membrane extends our work on free-standing double layer membranes. In recent years there is much interest in the study of phonon modes in nano-scale structures such as wires or dots. Although much theoretical work has been carried out in this direction, no experiments exist that explore the dispersion of the phonon modes in such structures. Brillouin Light scattering is ideally suited for studying phonons in such reduced dimensions and our work represents the first effort in this direction. The spectra reveal modes which are quantized both along the width, as well along the thickness

  11. Cylindrical light pipes for collecting light scattered from a Gaussian beam

    NASA Astrophysics Data System (ADS)

    Hopkins, George W.; Simons, Tad D.

    1999-10-01

    An investigation to enhance the efficiency of Raman- scattered light showed that cylindrical light pipes can significantly increase light collection from a Gaussian beam. Further, the enhanced signal from the light pipe retains the image of the laser beam, permitting the use of smaller detectors and resulting in a favorable signal-to- noise ratios. This investigation focussed on real-time measurements of gaseous media in a laser buildup cavity; however, the imaging properties of the light pipe apply to all measurements of molecular scattering. The light pipe matched the constraints of our measurement system: spectral separation and detection with an optical spectrograph, the need to reduce background light, the need to minimize cost, and stimulation by a laser beam in an optical cavity. After initial experiments collecting light from the ends of light pipes, we developed light pipes with a window on the cylindrical surface. Light emitted from these windows is much more intense than the direct image of the laser beam (typically 10X for light pipes 50 - 100 mm long), and the signal retains the image of the beam. Computer ray tracing modeled this side collection using Monte Carlo techniques, which are discussed in detail. We fabricated and tested light pipes using several different coatings.

  12. Screen anticancer drug in vitro using resonance light scattering technique.

    PubMed

    Chen, Zhanguang; Liu, Guoliang; Chen, Meizhen; Xu, Benjie; Peng, Yurui; Chen, Maohuai; Wu, Mingyao

    2009-02-15

    An in vitro screening model using resonance light scattering (RLS) technique with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reagent as the reactive probe to target cancer cell was firstly developed. In this model, MTT was reduced by viable cancer cells to produce a purple formazan. Cell viability was proportional to the number of formazan induced strong light scattering signal. The inhibition rate of anticancer drug was found to vary inversely with the H(22)-MTT system RLS intensity. So it was intuitive to see the sequence of the tumor suppressive activity of six anticancer drugs without data processing by RLS/MTT screening spectra. Compared with the traditional MTT method, this method has high sensitivity, low detection limit and quite intuitive screening results which were identical to those obtained from the MTT colorimetric assay.

  13. 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.

  14. Light-scattering and dispersion behavior of multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Saltiel, Craig; Manickavasagam, Siva; Pinar Mengüc, M.; Andrews, Rodney

    2005-08-01

    Elliptically polarized light-scattering measurements were performed to investigate the dispersion behavior of multiwalled carbon nanotubes (MWNT). Xylene- and pyridine-derived MWNT powders were dispersed in water and ethanol in separate optic cells and allowed to sit undisturbed over a two-week time period after probe sonication. Continuous light-scattering measurements taken between scattering angles of 10-170 deg and repeated over several days showed that the nanotubes formed fractal-like networks. The pyridine-derived MWNTs showed greater dispersion variation over time, tending to aggregate and clump much faster than the xylene-derived tubes. The water suspensions appeared much more stable than the ethanol suspensions, which transformed into nonfractal morphology after a few hours. We relate the dispersion stability to size and fringe patterns on the outer surface of the nanotubes. Measured values of fractal dimension were distinctly lower than those in previous studies of single-walled carbon nanotubes. Profiles of both diagonal and off-diagonal scattering matrix elements are presented.

  15. Scattered light in a DMD based multi-object spectrometer

    NASA Astrophysics Data System (ADS)

    Fourspring, Kenneth D.; Ninkov, Zoran; Kerekes, John P.

    2010-07-01

    The DMD (Digital Micromirror Device) has an important future in both ground and space based multi-object spectrometers. A series of laboratory measurements have been performed to determine the scattered light properties of a DMD. The DMD under test had a 17 μm pitch and 1 μm gap between adjacent mirrors. Prior characterization of this device has focused on its use in DLP (TI Digital Light Processing) projector applications in which a whole pixel is illuminated by a uniform collimated source. The purpose of performing these measurements is to determine the limiting signal to noise ratio when utilizing the DMD as a slit mask in a spectrometer. The DMD pixel was determined to scatter more around the pixel edge and central via, indicating the importance of matching the telescope point spread function to the DMD. Also, the generation of DMD tested here was determined to have a significant mirror curvature. A maximum contrast ratio was determined at several wavelengths. Further measurements are underway on a newer generation DMD device, which has a smaller mirror pitch and likely different scatter characteristics. A previously constructed instrument, RITMOS (RIT Multi-Object Spectrometer) will be used to validate these scatter models and signal to noise ratio predications through imaging a star field.

  16. 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.

  17. 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.

  18. 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.

  19. Chahine algorithm to invert light scattering spectroscopy of epithelial dysplasia

    NASA Astrophysics Data System (ADS)

    Wang, Qing-Hua; Li, Zhen-Hua; Lai, Jian-Cheng; He, An-Zhi

    2007-09-01

    To perceive the epithelial dysplasia from the light scattering spectroscopy (LSS) is an inverse problem, which can be transformed into the inversion of the size distribution of epithelial-cell nuclei. Based on the simulation of single polarized LSS for epithelial-cell nuclei, Chahine algorithm is adopted to retrieve the size distribution. Numerical results show that Chahine algorithm has high inversion precision for both single-peaked and bimodal models, which implies the potential to increase diagnostic resolution of LSS.

  20. Controlling Inelastic Light Scattering Quantum Pathways in Graphene

    DTIC Science & Technology

    2011-03-31

    applications. METHODS SUMMARY In this study we use large area graphene grown by chemical vapour deposition30. Graphene is grown on copper films using...the copper film by FeCl3. The PMMA support is dissolved in acetone solution. Subsequently, Ti (10 nm) and Au (40nm) were deposited in vacuum through...change of wave-length in light scattering.Nature 121, 619 (1928). 2. Landsberg, G. & Mandelstam, L. Eine neue Erscheinung bei der Lichtzerstreuung in

  1. 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.

  2. 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.

  3. 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.

  4. The self-association of acebutolol: Conductometry and light scattering

    NASA Astrophysics Data System (ADS)

    Ruso, Juan M.; López-Fontán, José L.; Prieto, Gerardo; Sarmiento, Félix

    2003-04-01

    The association characteristics of an amphiphilic beta-blocker drug, acebutolol hydrochloride, in aqueous solution containing high concentrations of electrolyte and at different temperatures have been examined by static and dynamic light scattering and electrical conductivity. Time averaged light scattering measurements on aqueous solutions of acebutolol at 298.15 K in the presence of added electrolyte (0.4-1.0 mol kg-1 NaCl) have shown discontinuities which reflect the appearance of aggregates. The critical micelle concentration, aggregation numbers, effective micelle charges, and degree of micellar ionization were calculated. Dynamic light scattering has shown an increase in micellar size with increase in concentration of added electrolyte. Data have been interpreted using the DLVO theory to quantify the interaction between the drug aggregates and the colloidal stability. Critical micelle concentrations in water have been calculated from conductivity measurements over the temperature range 288.15-313.15 K. The variation in critical concentration with temperature passes through a minimum close to 294 K. Thermodynamic parameters of aggregate formation (ΔGm0,ΔHm0,ΔSm0) were obtained from a variation of the mass action model applicable to systems of low aggregation number.

  5. Measurement of relative humidity dependent light scattering of aerosols

    NASA Astrophysics Data System (ADS)

    Fierz-Schmidhauser, R.; Zieger, P.; Wehrle, G.; Jefferson, A.; Ogren, J. A.; Baltensperger, U.; Weingartner, E.

    2009-09-01

    Relative humidity (RH) influences the water content of aerosol particles and therefore has an important impact on the particles' ability to scatter visible light. The RH dependence of the particle light scattering coefficient (σsp) is therefore an important measure for climate forcing calculations. We built a humidification system for a nephelometer which allows the measurement of σsp at a defined RH in the range of 40-90%. This RH conditioner consists of a humidifier followed by a dryer, which enables us to measure the hysteresis behavior of deliquescent aerosol particles. In this paper we present the set-up of a new humidified nephelometer, a detailed characterization with well defined laboratory generated aerosols, and a first application in the field by comparing our instrument to another humidified nephelometer. Monodisperse ammonium sulfate and sodium chloride particles were measured at four different dry particle sizes. Agreement between measurement and prediction based on Mie theory was found for both σsp and f(RH)=σsp(RH)/σsp(dry) within the range of uncertainty. The two humidified nephelometers measuring at a rural site in the Black Forest (Germany) often detected different f(RH), probably caused by the aerosol hysteresis behavior: when the aerosol was metastable, therefore was scattering more light, only one instrument detected the higher f(RH).

  6. Measurement of relative humidity dependent light scattering of aerosols

    NASA Astrophysics Data System (ADS)

    Fierz-Schmidhauser, R.; Zieger, P.; Wehrle, G.; Jefferson, A.; Ogren, J. A.; Baltensperger, U.; Weingartner, E.

    2010-01-01

    Relative humidity (RH) influences the water content of aerosol particles and therefore has an important impact on the particles' ability to scatter visible light. The RH dependence of the particle light scattering coefficient (σsp is therefore an important measure for climate forcing calculations. We built a humidification system for a nephelometer which allows the measurement of σsp at a defined RH in the range of 40-90%. This RH conditioner consists of a humidifier followed by a dryer, which enables us to measure the hysteresis behavior of deliquescent aerosol particles. In this paper we present the set-up of a new humidified nephelometer, a detailed characterization with well defined laboratory generated aerosols, and a first application in the field by comparing our instrument to another humidified nephelometer. Monodisperse ammonium sulfate and sodium chloride particles were measured at four different dry particle sizes. Agreement between measurement and prediction based on Mie theory was found for both σsp and f(RH)=σsp(RH)/σsp(dry) within the range of uncertainty. The two humidified nephelometers measuring at a rural site in the Black Forest (Germany) often detected different f(RH), probably caused by the aerosol hysteresis behavior: when the aerosol was metastable, therefore was scattering more light, only one instrument detected the higher f(RH).

  7. Analysis of light scattered by turbid media in cylindrical geometry.

    PubMed

    Tromp, R Hans; Liemert, André; Meinders, Marcel B J

    2014-07-22

    The angle dependence of the transmitted light through a cylindrical turbid sample (latex suspension, developing milk gel, draining/coarsening milk, and protein foams) in a standard light scattering setup was analyzed in terms of the transport mean free path length or scattering length l* (a measure for the turbidity) and the absorption length labs. By variation of the concentration of an absorbing dye, the independence of l* and labs was demonstrated. The resulting value of the specific extinction coefficient of the dye was found to be in fair agreement with direct spectroscopic determination and practically identical in milk and latex suspensions. The validity of this technique for obtaining l* was demonstrated by monitoring the acid-induced gelation of milk. The possibility to simultaneously determine l* and labs was used to follow the time development of a draining and coarsening protein foam which contained an absorbing dye. It was shown that labs can be used as a measure for the volume fraction of air in the foam. This method of monitoring the transmission of multiple light scattering provides an easy way to determine l* and, specifically for foams, quantitative data dominated by the bulk of the foam.

  8. Photon Correlation Spectroscopy and Electrophoretic Light Scattering Using Optical Fibres.

    NASA Astrophysics Data System (ADS)

    MacFadyen, Allan John

    Available from UMI in association with The British Library. In photon correlation spectroscopy, the fast local fluctuations in the intensity of the light scattered by submicron particles in suspension are recorded and analysed in terms of the particle motion. These may then be related to the particle size, or, when the particles are subjected to an electric field, the electrophoretic mobility. Light scattering apparatus traditionally incorporates a fixed goniometer arrangement. Recently, however, systems have been reported which incorporate optical fibres for use in remote or on-line situations. In this thesis, recent advances in the development of fibre-based photon correlation systems are reviewed and the design and construction of two novel optical fibre apparatus prototypes, incorporating "SELFOC" lenses, miniature prisms and single mode detection fibre, is discussed. The final outcome, an optical fibre sensor, which combines both photon correlation and electrophoretic light scattering measurements in a single, compact dip -in probe for the first time, is described. Results are presented for a variety of colloidal particles in suspension including polystyrene and "Microsilica" spheres, PTFE ellipsoids and kaolinite platelets, all of which demonstrate the viability of the apparatus.

  9. Determination of reversible protein equilibrium association coefficients using light scattering

    NASA Astrophysics Data System (ADS)

    Larkin, Michael

    2009-03-01

    The characterization in solution of reversible protein associations as well as associations between proteins and small molecules is essential in many areas of science. Understanding cellular function or developing and formulating pharmaceuticals or other biologically active materials often requires quantitation of such associations. Most pharmaceuticals have functionality due solely to association with molecules within the body, and the discovery and accurate characterization of these associations is a key element for pharmaceutical development. Unfortunately, most methods used to measure associations of proteins require either immobilizing the protein on a surface (e.g. surface plasmon resonance), which potentially alters the protein characteristics, or require considerable time and effort and large quantities of sample (e.g. analytical ultracentrifugation, isothermal titration calorimetry). Light scattering based measurements of reversible association coefficients require much less sample and may be performed much more rapidly than other free solution techniques. In this talk I describe how static and dynamic light scattering may each independently be used to measure equilibrium association coefficients between proteins in free solution, and may also be used to observe and quantitate the association of small molecules with them. I present background theory for both static and dynamic light scattering measurements of equilibrium associations, and examples of measurements made of both model systems and of systems with commercial relevance in the pharmaceutical industry.

  10. Photovoltaic structures having a light scattering interface layer and methods of making the same

    DOEpatents

    Liu, Xiangxin; Compaan, Alvin D.; Paudel, Naba Raj

    2015-10-13

    Photovoltaic (PV) cell structures having an integral light scattering interface layer configured to diffuse or scatter light prior to entering a semiconductor material and methods of making the same are described.

  11. Propagation and scattering of vector light beam in turbid scattering medium

    NASA Astrophysics Data System (ADS)

    Doronin, Alexander; Milione, Giovanni; Meglinski, Igor; Alfano, Robert R.

    2014-03-01

    Due to its high sensitivity to subtle alterations in medium morphology the vector light beams have recently gained much attention in the area of photonics. This leads to development of a new non-invasive optical technique for tissue diagnostics. Conceptual design of the particular experimental systems requires careful selection of various technical parameters, including beam structure, polarization, coherence, wavelength of incident optical radiation, as well as an estimation of how the spatial and temporal structural alterations in biological tissues can be distinguished by variations of these parameters. Therefore, an accurate realistic description of vector light beams propagation within tissue-like media is required. To simulate and mimic the propagation of vector light beams within the turbid scattering media the stochastic Monte Carlo (MC) technique has been used. In current report we present the developed MC model and the results of simulation of different vector light beams propagation in turbid tissue-like scattering media. The developed MC model takes into account the coherent properties of light, the influence of reflection and refraction at the medium boundary, helicity flip of vortexes and their mutual interference. Finally, similar to the concept of higher order Poincaŕe sphere (HOPS), to link the spatial distribution of the intensity of the backscattered vector light beam and its state of polarization on the medium surface we introduced the color-coded HOPS.

  12. Light organization of small particles by multiple scattering

    NASA Astrophysics Data System (ADS)

    Hang, Zhi Hong

    Optical manipulation is of broad interest in physics, chemistry, and biology. In the literature, most of the studies are focused on the optical trapping on a single object. In this thesis, we investigated the light-induced interaction of a collection of particles. The light-induced interaction between small particles was studied by a hierarchy of methods including the dipole theory, the multiple scattering and Maxwell stress tensor formalism, and the finite-difference-time-domain method. We showed that the multiple scattering between small particles could induce a binding mechanism to stabilize optically organized structures, but at the same time induced an intrinsic unbinding mechanism. The stability of optically organized structure was studied and a concept of "optical density" was introduced to gauge the destabilizing effect. We found that light-induced forces could bind dielectric spheres into extended structures through two mechanisms, each with its own length scale which could be adjusted by the configuration of the external light source. By manipulating the commensurability of the two length scales, these two mechanisms cooperated to bind a large number of spheres. When the two length scales became incommensurate for some particular incident angle, the competition between the two mechanisms led to modulated structures and other complex phenomena such as re-entrant stability. We searched for the possibility for stabilizing larger clusters. For this purpose, we found that circularly polarized light bound dielectric spheres into large-scale two-dimensional hexagonal lattice and multiple scattering also induced a rotation of optically bound structures. We searched for configurations that could induce optical trapping by field enhancement. Enhanced transmission on perforated metallic film system was studied. Surface modes bound on multi perforated perfect metal plate system were analytical solved and related to different high transmittance modes. Near

  13. Efficient Light Extraction from Organic Light-Emitting Diodes Using Plasmonic Scattering Layers

    SciTech Connect

    Rothberg, Lewis

    2012-11-30

    Our project addressed the DOE MYPP 2020 goal to improve light extraction from organic light-emitting diodes (OLEDs) to 75% (Core task 6.3). As noted in the 2010 MYPP, “the greatest opportunity for improvement is in the extraction of light from [OLED] panels”. There are many approaches to avoiding waveguiding limitations intrinsic to the planar OLED structure including use of textured substrates, microcavity designs and incorporating scattering layers into the device structure. We have chosen to pursue scattering layers since it addresses the largest source of loss which is waveguiding in the OLED itself. Scattering layers also have the potential to be relatively robust to color, polarization and angular distributions. We note that this can be combined with textured or microlens decorated substrates to achieve additional enhancement.

  14. Light scattering in colloidal solution of magnetite in electric and magnetic fields.

    PubMed

    Yerin, Constantine V

    2007-04-15

    Light scattering by magnetite particles in kerosene under the simultaneous action of crossed electric and magnetic fields was studied. Decreasing of variation of light scattering intensity at some values of electric and magnetic fields have been found. Values of fields at which a minimum of light scattering intensity occur depend on the angle between laser beam and the plane of crossed fields.

  15. Light Scattering and Absorption Studies of Sickle Cell Hemoglobin

    NASA Astrophysics Data System (ADS)

    Kim-Shapiro, Daniel

    1997-11-01

    The use of physical techniques has been very important in understanding the pathophysiology of sickle cell disease. In particular, light scattering and absorption studies have been used to measure the kinetics of sickle cell hemoglobin polymerization and depolymerization (melting). The theory of sickle cell polymerization that has been derived and tested by these methods has not only led to an increased understanding of the pathophysiology of the disease but has also led to improved treatment strategies. Sickle cell disease effects about 1 out of 600 people of African descent born in the United States. The disease is caused by a mutant form of hemoglobin (the oxygen transporting molecule in the blood), hemoglobin S (HbS), which differs from normal adult hemoglobin by the substitution of a single amino acid for another. The polymerization of HbS, which occurs under conditions of low oxygen pressure, causes distortion and increased rigidity of the sickle red blood cell that leads to blockage of the capillaries and a host of resulting complications. The disease is associated with tissue damage, severe painful crises and a high degree of mortality. Light scattering studies of purified HbS and whole cells (conducted by F.A. Ferrone, J. Hofrichter, W.A. Eaton, and their associates) have been used to determine the mechanism of HbS polymerization. Polymerization will generally not occur when the hemoglobin is in an oxygen-rich environment. The question is, when HbS is rapidly deoxygenated (as it is when going from the lungs to the tissues) what is the kinetics of polymerization? Photolysis methods were used to rapidly deoxygenate HbS and light scattering was used as a function of time to measure the kinetics of polymerization. Polarized light scattering may be a more effective way to measure polymer content than total intensity light scattering. It was found that no polymerization occurs during a period of time called the delay time and subsequent polymerization occurs

  16. Neutron activation analysis and X-ray Rayleigh and Raman scattering of hair and nail clippings as noninvasive bioindicators for Cu liver status in Labrador Retrievers

    PubMed Central

    Bueno, Maria Izabel Maretti Silveira; Bortoleto, Gisele G.; Hoffmann, Gaby; van den Ingh, Ted S. G. A. M.; Rothuizen, Jan

    2008-01-01

    The heritability of chronic hepatitis in the Labrador Retriever is studied with the aim of identifying the related gene mutation. Identification of cases and controls is largely based on instrumental neutron activation analysis (INAA) Cu determination in liver biopsies. The burden for these companion animals may be reduced if nail clippings and hair (fur) could serve as a noninvasive indicator for the hepatic Cu concentrations. No correlation was found between hepatic Cu concentrations and Cu concentrations in hair and nail samples. However, hair and nail samples were also analyzed by X-ray tube excitation, taking advantage of the X-ray Compton, Rayleigh, and Raman scattering which reflects the organic components such as the type of melanin. Principal component analysis provided first indications that some differentiation between healthy and sick dogs could indeed be obtained from hair and nail analysis. Figure Principal component analysis of scattered region of x-ray fluorescence spectra of Labrador dog nails, demonstrating the differentiation towards dogs with high and low Cu liver levels (respectively positive and negative PC2 values) reflecting hepatitis, as well as gender (PC1: negative values for female and positive values for males) PMID:18264701

  17. Determination of the critical premicelle concentration, first critical micelle concentration and second critical micelle concentration of surfactants by resonance Rayleigh scattering method without any probe

    NASA Astrophysics Data System (ADS)

    Shi, Yan; Luo, Hong Qun; Li, Nian Bing

    2011-05-01

    The purpose of this work is to determine the values of critical premicelle concentration (CPMC), first critical micelle concentration (FCMC) and second critical micelle concentration (SCMC) of surfactants using a common spectrofluorophotometer by recording resonance Rayleigh scattering (RRS) signal without any probe. The plot of the RRS intensities at the maximum scattering wavelength ( IRRSmax) versus surfactant concentrations ( c) was constructed to obtain the IRRSmax-c curve. From the inflexions in IRRSmax-c curve, the CPMC, FCMC and SCMC values of a surfactant can be obtained sensitively. The FCMC of some anionic, cationic and nonionic surfactants such as sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), Tween-20, and Tween-80 were determined by RRS method and the values are in good agreement with those obtained from conductivity and surface tension measurements and literature values. The CPMC and SCMC of SDS and CTAB were also determined by RRS method respectively and the values conform to literature values too. Furthermore, RRS method can also be used to determine the FCMC of an amphiphilic macromolecule-hemoglobin, whose structure resembles a surfactant. From the experimental results, it is concluded that RRS method can be applied to the simultaneous determination of the CPMC, FCMC and SCMC values in a sensitive, accurate and no probe way.

  18. Scattered light corrections to Sun photometry: analytical results for single and multiple scattering regimes.

    PubMed

    Kokhanovsky, Alexander A

    2007-04-01

    Analytical equations for the diffused scattered light correction factor of Sun photometers are derived and analyzed. It is shown that corrections are weakly dependent on the atmospheric optical thickness. They are influenced mostly by the size of aerosol particles encountered by sunlight on its way to a Sun photometer. In addition, the accuracy of the small-angle approximation used in the work is studied with numerical calculations based on the exact radiative transfer equation.

  19. An analytical approach to the multiply scattered light in the optical images of the extensive air showers of ultra-high energies

    NASA Astrophysics Data System (ADS)

    Giller, Maria; Śmiałkowski, Andrzej

    2012-08-01

    One of the methods for studying the highest energy cosmic rays is to measure the fluorescence light emitted by the extensive air showers induced by them. To reconstruct a shower cascade curve from measurements of the number of photons arriving from the subsequent shower track elements it is necessary to take into account the multiple scatterings that photons undergo on their way from the shower to the detector. In contrast to the earlier Monte-Carlo work, we present here an analytical method to treat the Rayleigh and Mie scatterings in the atmosphere. The method consists in considering separately the consecutive 'generations' of the scattered light. Starting with a point light source in a uniform medium, we then examine a source in a real atmosphere and finally - a moving source (shower) in it. We calculate the angular distributions of the scattered light superimposed on the not scattered light registered from a shower at a given time. The analytical solutions (although approximate) show how the exact numerical results should be parametrised what we do for the first two generations (the contribution of the higher ones being small). Not allowing for the considered effect may lead to an overestimation of shower primary energy by ˜15% and to an underestimation of the primary particle mass (E0=1019eV with the core distance 25 km and θZ=40°).

  20. LIGHT SOURCE: TW Laser system for Thomson scattering X-ray light source at Tsinghua University

    NASA Astrophysics Data System (ADS)

    Yan, Li-Xm; Du, Ying-Chao; Du, Qiang; Li, Ren-Kai; Hua, Jian-Fei; Huang, Wen-Hui; Tang, Chuan-Xiang

    2009-06-01

    A TW (Tera Watt) laser system based on Ti:sapphire mainly for the Tsinghua Thomson scattering X-ray light source (TTX) is being built. Both UV (ultraviolet) laser pulse for driving the photocathode radio-frequency (RF) gun and the IR (infrared) laser pulse as the electron-beam-scattered-light are provided by the system. Efforts have also been made in laser pulse shaping and laser beam transport to optimize the high-brightness electron beam production by the photocathode RF gun.