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Sample records for light scattering spectroscopy

  1. Microscopic Imaging and Spectroscopy with Scattered Light

    PubMed Central

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

    2012-01-01

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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Detecting skin malignancy using elastic light scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Canpolat, Murat; Akman, Ayşe; Çiftçioğlu, M. Akif; Alpsoy, Erkan

    2007-07-01

    We have used elastic light scattering spectroscopy to differentiate between malign and benign skin lesions. The system consists of a UV spectrometer, a single optical fiber probe and a laptop. The single optical fiber probe was used for both delivery and detection of white light to tissue and from the tissue. The single optical fiber probe received singly scattered photons rather than diffused photons in tissue. Therefore, the spectra are correlated with morphological differences of the cells. It has been shown that spectra of malign skin lesions are different than spectra of benign skin lesions. While slopes of the spectra taken on benign lesions or normal skin tissues were positive, slopes of the spectra taken on malign skin lesions tissues were negative. In vivo experiments were conducted on 20 lesions from 18 patients (11 men with mean age of 68 +/- 9 years and 7 women with mean age of 52 +/- 20 years) applied to the Department of Dermatology and Venerology. Before the biopsy, spectra were taken on the lesion and adjacent (approximately 1 cm distant) normal-appearing skin. Spectra of the normal skin were used as a control group. The spectra were correlated to the pathology results with sensitivity and specificity of 82% and 89%, respectively. Due to small diameter of fiber probe and limited number of sampling (15), some positive cases are missed, which is lowered the sensitivity of the system. The results are promising and could suggest that the system may be able to detect malignant skin lesion non-invasively and in real time.

  7. Inelastic light scattering spectroscopy in Si/SiGe nanostructures: Strain, chemical composition and thermal properties

    NASA Astrophysics Data System (ADS)

    Tsybeskov, L.; Mala, S. A.; Wang, X.; Baribeau, J.-M.; Wu, X.; Lockwood, D. J.

    2016-11-01

    We present a review of recent studies of inelastic light scattering spectroscopy in two types of Si/SiGe nanostructures: planar superlattices and cluster (dot) multilayers including first- and second-order Raman scattering, polarized Raman scattering and low-frequency inelastic light scattering associated with folded acoustic phonons. The results are used in semi-quantitative analysis of chemical composition, strain and thermal conductivity in these technologically important materials for electronic and optoelectronic devices.

  8. Aerosol particle absorption spectroscopy by photothermal modulation of Mie scattered light

    SciTech Connect

    Campillo, A.J.; Dodge, C.J.; Lin, H.B.

    1981-09-15

    Absorption spectroscopy of suspended submicron-sized aqueous ammonium-sulfate aerosol droplets has been performed by employing a CO/sub 2/ laser to photothermally modulate visible Mie scattered light. (AIP)

  9. Study of Brij Micelles Using Dynamic Light Scattering Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Karen; Lekan, Mike; Streletzky, Kiril

    2007-10-01

    We studied properties of Brij-35 surfactant micelles using Dynamic Light Scattering (DLS) and Optical Probe Diffusion method. Aqueous solutions of Brij-35 with concentrations ranging from 2 to 100g/L were prepared, both with and without polystyrene latex probes of diameters 24, 50, 282, and 792nm. Solutions were studied at four temperatures of 10, 25, 40, and 70^oC with DLS to obtain micelle and probe diffusion coefficients (Dm, Dp). Using both diffusion coefficients we deduced micelle radius (am), micelle water content (δ), and number of surfactant molecules per micelle (N) using two different models. First, we used the hard sphere model of micelle/probe interaction to analyze the data by two methods. In this model, am is obtained from Stokes-Einstein equation using the intercept of Dm(c). The first method of the model uses the slope of Dm(c) and the size of probes to determine N and δ. The second method of the model uses the linear least-squares fit of Dp(c) for different probe sizes to determine N and δ. Both methods reveal that with solution temperature increase, am increases by 10%, N increases and δ decreases by a factor of 2. Two hard sphere methods yield somewhat different trends, but overall agree with published data on Brij micelles. The second model treats micelles as core-shell particles and uses Dm(c) to determine not only am, δ, and N, but also micelle corona radius ac.

  10. Charactrisation of particle assemblies by 3D cross correlation light scattering and diffusing wave spectroscopy

    NASA Astrophysics Data System (ADS)

    Scheffold, Frank

    2014-08-01

    To characterize the structural and dynamic properties of soft materials and small particles, information on the relevant mesoscopic length scales is required. Such information is often obtained from traditional static and dynamic light scattering (SLS/DLS) experiments in the single scattering regime. In many dense systems, however, these powerful techniques frequently fail due to strong multiple scattering of light. Here I will discuss some experimental innovations that have emerged over the last decade. New methods such as 3D static and dynamic light scattering (3D LS) as well as diffusing wave spectroscopy (DWS) can cover a much extended range of experimental parameters ranging from dilute polymer solutions, colloidal suspensions to extremely opaque viscoelastic emulsions.

  11. Elastic light single-scattering spectroscopy for detection of dysplastic tissues

    NASA Astrophysics Data System (ADS)

    Canpolat, Murat; Denkçeken, Tuba; Akman, Ayşe.; Alpsoy, Erkan; Tuncer, Recai; Akyüz, Mahmut; Baykara, Mehmet; Yücel, Selçuk; Başsorgun, Ibrahim; ćiftçioǧlu, M. Akif; Gökhan, Güzide Ayşe.; Gürer, ElifInanç; Peştereli, Elif; Karaveli, Šeyda

    2013-11-01

    Elastic light single-scattering spectroscopy (ELSSS) system has been developed and tested in diagnosis of cancerous tissues of different organs. ELSSS system consists of a miniature visible light spectrometer, a single fiber optical probe, a halogen tungsten light source and a laptop. Measurements were performed on excised brain, skin, cervix and prostate tumor specimens and surrounding normal tissues. Single fiber optical probe with a core diameter of 100 μm was used to deliver white light to and from tissue. Single optical fiber probe mostly detects singly scattered light from tissue rather than diffused light. Therefore, measured spectra are sensitive to size of scatters in tissue such as cells, nuclei, mitochondria and other organelles of cells. Usually, nuclei of tumor cells are larger than nuclei of normal cells. Therefore, spectrum of singly scattered light of tumor tissue is different than normal tissue. The spectral slopes were shown to be positive for normal brain, skin and prostate and cervix tissues and negative for the tumors of the same tissues. Signs of the spectral slopes were used as a discrimination parameter to differentiate tumor from normal tissues for the three organ tissues. Sensitivity and specificity of the system in differentiation between tumors from normal tissues were 93% and %100 for brain, 87% and 85% for skin, 93.7% and 46.1% for cervix and 98% and 100% for prostate.

  12. Spectroscopy of diffuse light in dust clouds. Scattered light and the solar neighbourhood radiation field

    NASA Astrophysics Data System (ADS)

    Lehtinen, K.; Mattila, K.

    2013-01-01

    Context. The optical surface brightness of dark nebulae is mainly due to scattering of integrated starlight by classical dust grains. It contains information on the impinging interstellar radiation field, cloud structure, and grain scattering properties. We have obtained spectra of the scattered light from 3500 to 9000 Å in two globules, the Thumbprint Nebula and DC 303.8-14.2. Aims. We use observations of the scattered light to study the impinging integrated starlight spectrum as well as the scattered Hα and other line emissions from all over the sky. We search also for the presence of other than scattered light in the two globules. Methods. We obtained long-slit spectra encompassing the whole globule plus adjacent sky in a one-slit setting, thus enabling efficient elimination of airglow and other foreground sky components. We calculated synthetic integrated starlight spectra for the solar neighbourhood using HIPPARCOS-based stellar distributions and the spectral library of Pickles. Results. Spectra are presented separately for the bright rims and dark cores of the globules. The continuum spectral energy distributions and absorption line spectra can be well modelled with the synthetic integrated starlight spectra. Emission lines of Hα +[N II], Hβ, and [S II] are detected and are interpreted in terms of scattered light plus an in situ warm ionized medium component behind the globules. We detected an excess of emission over the wavelength range 5200-8000 Å in DC 303.8-14.2 but the nature of this emission remains open. Based on observations collected at the European Southern Observatory, Chile, under programme ESO No. 073.C-0239(A). Appendix A is available in electronic form at http://www.aanda.org.

  13. Two-tone frequency modulation spectroscopy from laser light scattered off a hard target.

    PubMed

    Powers, P E; Taatjes, C A; Kulp, T J

    1996-08-20

    One can apply two-tone frequency modulation spectroscopy techniques to the detection of gas-phase species by using laser light scattered from hard targets. High sensitivities are demonstrated, with a minimum detectable absorption of 10(-4) possible with a simple apparatus. The effects of laser speckle on the FM signal are described, and we show that the detection signal-to-noise ratio can be improved by collecting an increased number of speckle cells.

  14. Assessing epithelial cell nuclear morphology by using azimuthal light scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Yu, Chung-Chieh; Lau, Condon; Tunnell, James W.; Hunter, Martin; Kalashnikov, Maxim; Fang-Yen, Christopher; Fulghum, Stephen F.; Badizadegan, Kamran; Dasari, Ramachandra R.; Feld, Michael S.

    2006-11-01

    We describe azimuthal light scattering spectroscopy (ϕ/LSS), a novel technique for assessing epithelial-cell nuclear morphology. The difference between the spectra measured at azimuthal angles ϕ=0° and ϕ=90° preferentially isolates the single backscattering contribution due to large (˜10 μm) structures such as epithelial cell nuclei by discriminating against scattering from smaller organelles and diffusive background. We demonstrate the feasibility of using ϕ/LSS for cancer detection by showing that spectra from cancerous colon tissue exhibit significantly greater azimuthal asymmetry than spectra from normal colonic tissues.

  15. Surface plasmon excitations in metal spheres: Direct comparison of light scattering and electron energy-loss spectroscopy by modal decomposition

    NASA Astrophysics Data System (ADS)

    Collins, Sean M.; Midgley, Paul A.

    2013-06-01

    In previous publications, qualitative agreement between studies of surface plasmon excitations in nanoparticles by near-field light scattering and electron energy-loss spectroscopy (EELS) has been found for experiments and simulations. Here, we present a quantitative method for the comparison of light scattering and EELS for surface plasmons in metal spheres. Defining the Fourier transform of the modal component of the scattered electric field along the equivalent electron trajectory enables a direct evaluation of the relative weighting factor for light- and electron-excited surface plasmon modes. This common quantity for light scattering and EELS is examined for size, composition, and trajectory dependencies, facilitating the analysis of key differences between light and electron excitation. A single functional dependence on Drude model plasmon energies is identified to explain the relative modal weighting factors for light scattering and EELS. This method represents an important step toward the complete spectral and spatial reconstruction of EELS maps from near-field light scattering calculations.

  16. Broadband light scattering spectroscopy utilizing an ultra-narrowband holographic notch filter

    NASA Astrophysics Data System (ADS)

    Fujii, Yasuhiro; Katayama, Daisuke; Koreeda, Akitoshi

    2016-10-01

    The broadband spectroscopic analysis over Brillouin, quasi-elastic, and Raman regions arising from the same position of the sample has been achieved by employing an ultra-narrowband holographic notch filter (HNF) and an optical isolator. Recently, HNFs are often employed to reject strong elastic scattering in low-frequency Raman experiments. Meanwhile, the rejected spectral component agrees with the frequency range that can be observed by a triple-pass tandem Fabry-Pérot interferometer. Thus the broadband spectroscopy can be accomplished by introducing the rejected light to the interferometer. This system, in combination with the local symmetry analysis by polarization-direction-resolved Raman spectroscopy, is particularly advantageous for the investigation of spatially inhomogeneous systems.

  17. Optical and Physicochemical Properties of Brown Carbon Aerosol: Light Scattering, FTIR Extinction Spectroscopy, and Hygroscopic Growth.

    PubMed

    Tang, Mingjin; Alexander, Jennifer M; Kwon, Deokhyeon; Estillore, Armando D; Laskina, Olga; Young, Mark A; Kleiber, Paul D; Grassian, Vicki H

    2016-06-23

    A great deal of attention has been paid to brown carbon aerosol in the troposphere because it can both scatter and absorb solar radiation, thus affecting the Earth's climate. However, knowledge of the optical and chemical properties of brown carbon aerosol is still limited. In this study, we have investigated different aspects of the optical properties of brown carbon aerosol that have not been previously explored. These properties include extinction spectroscopy in the mid-infrared region and light scattering at two different visible wavelengths, 532 and 402 nm. A proxy for atmospheric brown carbon aerosol was formed from the aqueous reaction of ammonium sulfate with methylglyoxal. The different optical properties were measured as a function of reaction time for a period of up to 19 days. UV/vis absorption experiments of bulk solutions showed that the optical absorption of aqueous brown carbon solution significantly increases as a function of reaction time in the spectral range from 200 to 700 nm. The analysis of the light scattering data, however, showed no significant differences between ammonium sulfate and brown carbon aerosol particles in the measured scattering phase functions, linear polarization profiles, or the derived real parts of the refractive indices at either 532 or 402 nm, even for the longest reaction times with greatest visible extinction. The light scattering experiments are relatively insensitive to the imaginary part of the refractive index, and it was only possible to place an upper limit of k ≤ 0.01 on the imaginary index values. These results suggest that after the reaction with methylglyoxal the single scattering albedo of ammonium sulfate aerosol is significantly reduced but that the light scattering properties including the scattering asymmetry parameter, which is a measure of the relative amount of forward-to-backward scattering, remain essentially unchanged from that of unprocessed ammonium sulfate. The optical extinction properties

  18. [Particle Size and Number Density Online Analysis for Particle Suspension with Polarization-Differentiation Elastic Light Scattering Spectroscopy].

    PubMed

    Chen, Wei-kang; Fang, Hui

    2016-03-01

    The basic principle of polarization-differentiation elastic light scattering spectroscopy based techniques is that under the linear polarized light incidence, the singlely scattered light from the superficial biological tissue and diffusively scattered light from the deep tissue can be separated according to the difference of polarization characteristics. The novel point of the paper is to apply this method to the detection of particle suspension and, to realize the simultaneous measurement of its particle size and number density in its natural status. We design and build a coaxial cage optical system, and measure the backscatter signal at a specified angle from a polystyrene microsphere suspension. By controlling the polarization direction of incident light with a linear polarizer and adjusting the polarization direction of collected light with another linear polarizer, we obtain the parallel polarized elastic light scattering spectrum and cross polarized elastic light scattering spectrum. The difference between the two is the differential polarized elastic light scattering spectrum which include only the single scattering information of the particles. We thus compare this spectrum to the Mie scattering calculation and extract the particle size. We then also analyze the cross polarized elastic light scattering spectrum by applying the particle size already extracted. The analysis is based on the approximate expressions taking account of light diffusing, from which we are able to obtain the number density of the particle suspension. We compare our experimental outcomes with the manufacturer-provided values and further analyze the influence of the particle diameter standard deviation on the number density extraction, by which we finally verify the experimental method. The potential applications of the method include the on-line particle quality monitoring for particle manufacture as well as the fat and protein density detection of milk products.

  19. 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.

  20. Experimental and theoretical realization of enhanced light scattering spectroscopy of gold nanorods

    SciTech Connect

    Li, Yunbo; Song, Linlin; Qiao, Yisha

    2015-01-12

    Assisted with transmission electron microscopy and extinction spectra, the enhanced light scattering (ELS) experiments were performed with gold nanoparticles. Although both the nanospheres and nanorods can enhance light scattering in study aggregation, the spectral characteristics of gold nanorods is relatively simple compared to that of nanospheres. This will further extend the application range of ELS method to determinate the amounts of inorganic ions in analytical field and investigate on the macromolecular aggregation in polymeric research due to its simplicity, rapidity, and sensitivity.

  1. UV-vis spectroscopy and dynamic light scattering study of gold nanorods aggregation.

    PubMed

    Kanjanawarut, Roejarek; Yuan, Bo; XiaoDi, Su

    2013-08-01

    Gold nanorods (AuNRs) were used as spectroscopic sensing elements to detect specific DNA sequences with a single-base mismatch sensitivity. The assay was based on the observation that the stabilizing repulsive forces between CTA(+)-coated AuNRs can be removed by citrate ions, which causes aggregation among AuNRs; whereas nucleic acids of different structures[ i.e., peptide nucleic acid (PNA), single-stranded DNA (ssDNA), PNA-DNA complex, and double-stranded DNA (dsDNA)] can retard the aggregation. Moreover, the dsDNA PNA-DNA duplexes provide larger retardation than that by unhybridized ssDNA and PNA probe. This assay can differentiate single-base mismatched targets with base substitution at different locations (center and end) with AuNRs of a larger aspect ratio. Besides ultraviolet-visable spectroscopy measurement of particle assembly-induced plasmonic coupling that in turn provides a spectroscopic detection of the specific DNA, dynamic light scattering and transmission electron microscope (TEM) were used to measure smaller degree of aggregation that can reveal sodium citrate- and dsDNA-AuNRs interactions in fine detail.

  2. Noninvasive identification of subcellular organization and nuclear morphology features associated with leukemic cells using light-scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Hsiao, Austin; Hunter, Martin; Greiner, Cherry; Gupta, Sharad; Georgakoudi, Irene

    2011-03-01

    Leukemia is the most common and deadly cancer among children and one of the most prevalent cancers among adults. Improvements in its diagnosis and monitoring of leukemic patients could have a significant impact in their long-term treatment. We demonstrate that light-scattering spectroscopy (LSS)-based approaches could serve as a tool to achieve this goal. Specifically, we characterize the light scattering properties of leukemic (NALM-6) cells and compare them to those of normal lymphocytes and granulocytes in the 440-710 nm range, over +/-4 deg about the exact backscattering direction. We find that the LSS spectra are well described by an inverse power-law wavelength dependence, with a power exponent insensitive to the scattering angle but significantly higher for leukemic cells than for normal leukocytes. This is consistent with differences in the subcellular morphology of these cells, detected in differential interference contrast images. Furthermore, the residual light-scattering signal, extracted after subtracting the inverse power-law fit from the data, can be analyzed assuming a Gaussian distribution of spherical scatterers using Mie theory. This analysis yields scatterer sizes that are consistent with the diameters of cell nuclei and allows the detection of the larger nuclei of NALM-6 cells compared to those of lymphocytes and granulocytes.

  3. Using resonance light scattering and UV/vis absorption spectroscopy to study the interaction between gliclazide and bovine serum albumin.

    PubMed

    Zhang, Qiu-Ju; Liu, Bao-Sheng; Li, Gai-Xia; Han, Rong

    2016-08-01

    At different temperatures (298, 310 and 318 K), the interaction between gliclazide and bovine serum albumin (BSA) was investigated using fluorescence quenching spectroscopy, resonance light scattering spectroscopy and UV/vis absorption spectroscopy. The first method studied changes in the fluorescence of BSA on addition of gliclazide, and the latter two methods studied the spectral change in gliclazide while BSA was being added. The results indicated that the quenching mechanism between BSA and gliclazide was static. The binding constant (Ka ), number of binding sites (n), thermodynamic parameters, binding forces and Hill's coefficient were calculated at three temperatures. Values for the binding constant obtained using resonance light scattering and UV/vis absorption spectroscopy were much greater than those obtained from fluorescence quenching spectroscopy, indicating that methods monitoring gliclazide were more accurate and reasonable. In addition, the results suggest that other residues are involved in the reaction and the mode 'point to surface' existed in the interaction between BSA and gliclazide. Copyright © 2015 John Wiley & Sons, Ltd.

  4. 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.

  5. Optical spectroscopy of HH-exciting stars from scattered light continua

    NASA Technical Reports Server (NTRS)

    Cohen, M.; Dopita, M. A.; Schwartz, R. D.

    1986-01-01

    Optical spectra of the reflected light continua visible in parts of several Herbig-Haro objects are presented. HH 100 unmistakably scatters the chromospheric spectrum of a strong emission-line T Tau star. HH 48S also reflects a T Tau stellar spectrum, as perhaps do HH 24 and HH 55, but less convincingly. HH 55 reveals photospheric absorption features too, corresponding to an M3.5 T Tau star. The continuum in HH 120 (= CG 30 HH) is unclassifiable while that in HH 46A has dimmed considerably (by a factor of order 20) although, only 7 yr ago, it clearly reflected a strong-line T Tau spectrum. It is concluded that at least some of the stars that excite Herbig-Haro nebulae, even when those stars are not directly visible, pass through a strong-line T Tau phase, and can undergo abrupt and dramatic changes in visual luminosity.

  6. Resonance light scattering spectroscopy of procyanidin-CPB-DNA ternary system and its potential application

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Bi, Shuyun; Zhou, Huifeng; Zhao, Tingting

    2015-07-01

    A new method for the determination of calf thymus DNA at nanogram level was proposed based on the enhanced resonance light scattering (RLS) signals of DNA in the presence of procyanidin and cetylpyridinium bromide dihydrate (CPB). Under the experimental conditions, the RLS intensity of DNA at 291.0 nm was greatly enhanced by procyanidin-CPB at pH 7.0. There was a good linear relationship (r = 0.9993) between the enhanced RLS intensity (ΔIRLS) and DNA concentration of 0.0084-3.36 μg mL-1. The limit of detection (LOD) was 2.27 ng mL-1 (3S0/S). Three synthetic DNA samples were measured with satisfactory, and the recovery was 102.3-107.2%.

  7. Identifying mitosis deep in tissue using dynamic light scattering fluctuation spectroscopy

    NASA Astrophysics Data System (ADS)

    An, Ran; Jeong, Kwan; Turek, John; Nolte, David

    2012-03-01

    In the cell cycle, mitosis is the most dramatic phase, especially in Telophase and Cytokinesis. For single cells and cell monolayer, there are precise microscopic studies of mitosis, while for 3-D tissue such as tumor spheroids the light signal is obscured by the high background of diffusely scattered light. Therefore, the mitosis phase cannot be detected deep inside 3-D tissue using conventional microscopic techniques. In this work, we detect mitosis in living tissue using Tissue Dynamic Imaging (TDI). We trace depth-gated dynamic speckles from a tumor spheroid (up to 1mm in diameter) using coherence-gated digital holography imaging. Frequency-versus-time spectrograms depend on specific types of perturbation such as cell shape change, membrane undulation and cell organelles movements. By using these spectral responses as functional finger prints, we can identify mitosis events from different voxels at a specified depth inside tumor spheroids. By performing B-scans of the tumor spheroid, we generate 3-D mitosis maps (or movies) for the entire tumor spheroids. We show that for healthy tumor spheroids, the mitosis events only happen within the proliferating shell. We also compare results when anti-cancer drugs are applied to arrest, release and synchronize mitosis. This shows the application of TDI for drug screening. The technique can identify and monitor complex motilities inside 3-D tissue with a strong potential for drug diagnosis and developmental biology studies.

  8. Concomitant Raman spectroscopy and dynamic light scattering for characterization of therapeutic proteins at high concentrations.

    PubMed

    Zhou, Chen; Qi, Wei; Lewis, E Neil; Carpenter, John F

    2015-03-01

    A Raman spectrometer and dynamic light scattering system were combined in a single platform (Raman-DLS) to provide concomitant higher order structural and hydrodynamic size data for therapeutic proteins at high concentration. As model therapeutic proteins, we studied human serum albumin (HSA) and intravenous immunoglobulin (IVIG). HSA concentration and temperature interval during heating did not affect the onset temperatures for conformation perturbation or aggregation. The impact of pH on thermal stability of HSA was tested at pHs 3, 5, and 8. Stability was the greatest at pH 8, but distinct unfolding and aggregation behaviors were observed at the different pHs. HSA structural transitions and aggregation kinetics were also studied in real time during isothermal incubations at pH 7. In a forced oxidation study, it was found that hydrogen peroxide (H2O2) treatment reduced the thermal stability of HSA. Finally, the structure and thermal stability of IVIG were studied, and a comprehensive characterization of heating-induced structural perturbations and aggregation was obtained. In conclusion, by providing comprehensive data on protein tertiary and secondary structures and hydrodynamic size during real-time heating or isothermal incubation experiments, the Raman-DLS system offers unique physical insights into the properties of high-concentration protein samples.

  9. Broadband light-scattering spectroscopy on fractal and non-fractal relaxors

    NASA Astrophysics Data System (ADS)

    Koreeda, Akitoshi; Ogawa, Tomohiro; Katayama, Daisuke; Fujii, Yasuhiro; Tachibana, Makoto

    2016-10-01

    We show the quasi-elastic light scattering (QELS) spectra of two groups of relaxors: the first group includes relaxors that exhibit glasslike low-temperature thermal conductivity and heat capacity, namely, Pb(Mg1/3Nb2/3)O3 (PMN), (1 - x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT), Pb(Zr1/3Nb2/3)O3 (PZN), and (Na1/2Bi1/2)TiO3 (NBT). The other group consists of relaxors exhibiting a normal (crystal) temperature dependence of the thermal conductivity and heat capacity, namely, K1- x Li x TaO3 (KLT) and KTa1- x Nb x O3 (KTN). The crystals of the first group yielded self-similar (power-law) QELS spectra, indicating the existence of fractal networks/clusters of polar nanoregions, while those of the second group did not show any self-similarity in the QELS spectra. These results imply that the glasslike low-temperature thermal conductivity and heat capacity in relaxors can be attributed to the vibrational modes specific to fractal networks/clusters formed by polar nanoregions.

  10. Nanowire Electron Scattering Spectroscopy

    NASA Technical Reports Server (NTRS)

    Hunt, Brian; Bronikowsky, Michael; Wong, Eric; VonAllmen, Paul; Oyafuso, Fablano

    2009-01-01

    Nanowire electron scattering spectroscopy (NESS) has been proposed as the basis of a class of ultra-small, ultralow-power sensors that could be used to detect and identify chemical compounds present in extremely small quantities. State-of-the-art nanowire chemical sensors have already been demonstrated to be capable of detecting a variety of compounds in femtomolar quantities. However, to date, chemically specific sensing of molecules using these sensors has required the use of chemically functionalized nanowires with receptors tailored to individual molecules of interest. While potentially effective, this functionalization requires labor-intensive treatment of many nanowires to sense a broad spectrum of molecules. In contrast, NESS would eliminate the need for chemical functionalization of nanowires and would enable the use of the same sensor to detect and identify multiple compounds. NESS is analogous to Raman spectroscopy, the main difference being that in NESS, one would utilize inelastic scattering of electrons instead of photons to determine molecular vibrational energy levels. More specifically, in NESS, one would exploit inelastic scattering of electrons by low-lying vibrational quantum states of molecules attached to a nanowire or nanotube.

  11. Effect of ethanol on dimyristoylphosphatidylcholine large unilamellar vesicles investigated by quasi-elastic light scattering and vibrational spectroscopy.

    PubMed

    Hantz, E; Cao, A; Taillandier, E

    1988-12-01

    The gel-like liquid phase transition of dimyristoylphosphatidylcholine (DMPC) large unilamellar vesicles prepared by reverse phase evaporation has been investigated in buffers containing ethanol by quasi-elastic light scattering (QLS) and vibrational (infrared and Raman) spectroscopy. With the QLS technique, the relative change in the vesicles area (which is related to the molecular cross-sectional area of lipid molecules) was followed versus both temperature and ethanol concentration. When the latter was low, the depression of the transition point was a linear function of the alcohol concentration, c, but the vesicles area was practically unmodified. At alcohol concentration 10% v/v, an abrupt change of the vesicles area was observed and for c greater than 10% the depression of the transition point was a non-linear function of c. The infrared and Raman spectra showed a perturbation of the hydrophobic regions, including the terminal methyl groups of the acyl tails.

  12. Size-dependent magnetization dynamics in individual Ni80Fe20 disk using micro-focused Brillouin Light Scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Shimon, G.; Adeyeye, A. O.

    2015-09-01

    A direct and systematic investigation of the magnetization dynamics in individual circular Ni80Fe20 disk of diameter (D) in the range from 300 nm to 1 μm measured using micro-focused Brillouin Light Scattering (μ-BLS) spectroscopy is presented. At high field, when the disks are in a single domain state, the resonance frequency of the uniform center mode is observed to reduce with reducing disk's diameter. For D = 300 nm, additional edge and end-domains resonant modes are observed due to size effects. At low field, when the disks are in a vortex state, a systematic increase of resonant frequency of magnetostatic modes in a vortex state with the square root of the disks' aspect ratio (thickness divided by radius) is observed. Such dependence diminishes for disks with larger aspect ratio due to an increasing exchange energy contribution. Micromagnetic simulations are in excellent agreement with the experiments.

  13. 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.

  14. Interferometric Spectroscopy of Scattered Light Can Quantify the Statistics of Subdiffractional Refractive-Index Fluctuations

    NASA Astrophysics Data System (ADS)

    Cherkezyan, L.; Capoglu, I.; Subramanian, H.; Rogers, J. D.; Damania, D.; Taflove, A.; Backman, V.

    2013-07-01

    Despite major importance in physics, biology, and other sciences, the optical sensing of nanoscale structures in the far zone remains an open problem due to the fundamental diffraction limit of resolution. We establish that the expected value of spectral variance (Σ˜2) of a far-field, diffraction-limited microscope image can quantify the refractive-index fluctuations of a label-free, weakly scattering sample at subdiffraction length scales. We report the general expression of Σ˜ for an arbitrary refractive-index distribution. For an exponential refractive-index spatial correlation, we obtain a closed-form solution of Σ˜ that is in excellent agreement with three-dimensional finite-difference time-domain solutions of Maxwell’s equations. Sensing complex inhomogeneous media at the nanoscale can benefit fields from material science to medical diagnostics.

  15. Interferometric spectroscopy of scattered light can quantify the statistics of subdiffractional refractive-index fluctuations.

    PubMed

    Cherkezyan, L; Capoglu, I; Subramanian, H; Rogers, J D; Damania, D; Taflove, A; Backman, V

    2013-07-19

    Despite major importance in physics, biology, and other sciences, the optical sensing of nanoscale structures in the far zone remains an open problem due to the fundamental diffraction limit of resolution. We establish that the expected value of spectral variance (Σ[over ˜](2)) of a far-field, diffraction-limited microscope image can quantify the refractive-index fluctuations of a label-free, weakly scattering sample at subdiffraction length scales. We report the general expression of Σ[over ˜] for an arbitrary refractive-index distribution. For an exponential refractive-index spatial correlation, we obtain a closed-form solution of Σ[over ˜] that is in excellent agreement with three-dimensional finite-difference time-domain solutions of Maxwell's equations. Sensing complex inhomogeneous media at the nanoscale can benefit fields from material science to medical diagnostics.

  16. Interferometric spectroscopy of scattered light can quantify the statistics of subdiffractional refractive-index fluctuations

    PubMed Central

    Cherkezyan, L.; Capoglu, I.; Subramanian, H.; Rogers, J. D.; Damania, D.; Taflove, A.

    2014-01-01

    Despite major importance in physics, biology, and other sciences, optical sensing of nanoscale structures in the far-zone remains an open problem due to the fundamental diffraction limit of resolution. We establish that the expected value of spectral variance (Σ̃2) of a far-field, diffraction-limited microscope image can quantify the refractive-index fluctuations of a label-free, weakly scattering sample at subdiffraction length scales. We report the general expression of Σ̃ for an arbitrary refractive-index distribution. For an exponential refractive-index spatial correlation, we obtain a closed-form solution of Σ̃ which is in excellent agreement with three-dimensional finite-difference time-domain solutions of Maxwell's equations. Sensing complex inhomogeneous media at the nanoscale can benefit fields from material science to medical diagnostics. PMID:23909326

  17. 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.

  18. 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.

  19. Feasibility of minimally-invasive fiber-based evaluation of chondrodystrophoid canine intervertebral discs by light absorption and scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Yuanyuan; McKeirnan, Kelci; Piao, Daqing; Bartels, Kenneth E.

    2011-03-01

    Extrusion or protrusion of an intervertebral disc is a common, frequently debilitating, painful, and sometimes fatal neurologic disease in the chondrodystrophic dog (dachshund, Pekingese, etc.). A similar condition of intervertebral disc degeneration with extrusion/protrusion is also a relatively common neurologic condition in human patients. Degeneration of the relatively avascular chondrodystrophoid intervertebral disc is associated with loss of water content, increased collagen, and deposits of calcified mineral in the nucleus pulposus. Current diagnostic methods have many limitations for providing accurate information regarding disc composition in situ prior to surgical intervention. Disc composition (i.e., mineralization), can influence the type of treatment regime and potentially prognosis and recurrence rates. The objective of this study is to investigate the feasibility of using a fiber-needle spectroscopy sensor to analyze the changes of tissue compositions involved in the chondrodystrophoid condition of the canine intervertebral disc. The nucleous pulposus, in which the metaplastic process / degeneration develops, is approximately 2mm thick and 5mm in diameter in the dachshund-sized dog. It lies in the center of the disc, surrounded by the annulus fibrosis and is enclosed by cartilaginous vertebral endplates cranially and caudally. This "shallow-and-small-slab" geometry limits the configuration of a fiber probe to sense the disc tissue volume without interference from the vertebrae. A single-fiber sensor is inserted into a 20 gauge myelographic spinal needle for insertion into the disc in situ and connected via a bifurcated fiber to the light source and a spectrometer. A tungsten light source and a 940nm light-emitting-diode are combined for spectral illumination covering VIS/NIR with expected improved sensitivity to water. Analysis of the reflectance spectra is expected to provide information of scattering and absorption compositions of tissue in

  20. Heat-denatured lysozyme aggregation and gelation as revealed by combined dielectric relaxation spectroscopy and light scattering measurements.

    PubMed

    Giugliarelli, A; Sassi, P; Paolantoni, M; Onori, G; Cametti, C

    2012-09-06

    The dielectric behavior of native and heat-denatured lysozyme in ethanol-water solutions was examined in the frequency range from 1 MHz to 2 GHz, using frequency-domain dielectric relaxation spectroscopy. Because of the conformational changes on unfolding, dielectric methods provide information on the denaturation process of the protein and, at protein concentration high enough, on the subsequent aggregation and gelation. Moreover, the time evolution of the protein aggregation and gelation was monitored measuring, by means of dynamic light scattering methods, the diffusion coefficient of micro-sized polystyrene particles, deliberately added to the protein solution, which act as a probe of the viscosity of the microenvironment close to the particle surface. All together, our measurements indicate that heat-induced denaturation favors, at high concentrations, a protein aggregation process which evolves up to the full gelation of the system. These findings have a direct support from IR measurements of the absorbance of the amide I band that, because of the unfolding, indicate that proteins entangle each other, producing a network structure which evolves, in long time limit, in the gel.

  1. 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

  2. Probing multi-scale self-similarity of tissue structures using light scattering spectroscopy: prospects in pre-cancer detection

    NASA Astrophysics Data System (ADS)

    Chatterjee, Subhasri; Das, Nandan K.; Kumar, Satish; Mohapatra, Sonali; Pradhan, Asima; Panigrahi, Prasanta K.; Ghosh, Nirmalya

    2013-02-01

    Multi-resolution analysis on the spatial refractive index inhomogeneities in the connective tissue regions of human cervix reveals clear signature of multifractality. We have thus developed an inverse analysis strategy for extraction and quantification of the multifractality of spatial refractive index fluctuations from the recorded light scattering signal. The method is based on Fourier domain pre-processing of light scattering data using Born approximation, and its subsequent analysis through Multifractal Detrended Fluctuation Analysis model. The method has been validated on several mono- and multi-fractal scattering objects whose self-similar properties are user controlled and known a-priori. Following successful validation, this approach has initially been explored for differentiating between different grades of precancerous human cervical tissues.

  3. 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.

  4. Improved Optics For Quasi-Elastic Light Scattering

    NASA Technical Reports Server (NTRS)

    Cheung, Harry Michael

    1995-01-01

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

  5. Nanowire electron scattering spectroscopy

    NASA Technical Reports Server (NTRS)

    Hunt, Brian D. (Inventor); Bronikowski, Michael (Inventor); Wong, Eric W. (Inventor); von Allmen, Paul (Inventor); Oyafuso, Fabiano A. (Inventor)

    2009-01-01

    Methods and devices for spectroscopic identification of molecules using nanoscale wires are disclosed. According to one of the methods, nanoscale wires are provided, electrons are injected into the nanoscale wire; and inelastic electron scattering is measured via excitation of low-lying vibrational energy levels of molecules bound to the nanoscale wire.

  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. Portable sample preparation and analysis system for micron and sub-micron particle characterization using light scattering and absorption spectroscopy

    DOEpatents

    Stark, Peter C.; Zurek, Eduardo; Wheat, Jeffrey V.; Dunbar, John M.; Olivares, Jose A.; Garcia-Rubio, Luis H.; Ward, Michael D.

    2011-07-26

    There is provided a method and device for remote sampling, preparation and optical interrogation of a sample using light scattering and light absorption methods. The portable device is a filtration-based device that removes interfering background particle material from the sample matrix by segregating or filtering the chosen analyte from the sample solution or matrix while allowing the interfering background particles to be pumped out of the device. The segregated analyte is then suspended in a diluent for analysis. The device is capable of calculating an initial concentration of the analyte, as well as diluting the analyte such that reliable optical measurements can be made. Suitable analytes include cells, microorganisms, bioparticles, pathogens and diseases. Sample matrixes include biological fluids such as blood and urine, as well as environmental samples including waste water.

  8. 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.

  9. Quantification and parametrization of non-linearity effects by higher-order sensitivity terms in scattered light differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Puķīte, Jānis; Wagner, Thomas

    2016-05-01

    We address the application of differential optical absorption spectroscopy (DOAS) of scattered light observations in the presence of strong absorbers (in particular ozone), for which the absorption optical depth is a non-linear function of the trace gas concentration. This is the case because Beer-Lambert law generally does not hold for scattered light measurements due to many light paths contributing to the measurement. While in many cases linear approximation can be made, for scenarios with strong absorptions non-linear effects cannot always be neglected. This is especially the case for observation geometries, for which the light contributing to the measurement is crossing the atmosphere under spatially well-separated paths differing strongly in length and location, like in limb geometry. In these cases, often full retrieval algorithms are applied to address the non-linearities, requiring iterative forward modelling of absorption spectra involving time-consuming wavelength-by-wavelength radiative transfer modelling. In this study, we propose to describe the non-linear effects by additional sensitivity parameters that can be used e.g. to build up a lookup table. Together with widely used box air mass factors (effective light paths) describing the linear response to the increase in the trace gas amount, the higher-order sensitivity parameters eliminate the need for repeating the radiative transfer modelling when modifying the absorption scenario even in the presence of a strong absorption background. While the higher-order absorption structures can be described as separate fit parameters in the spectral analysis (so-called DOAS fit), in practice their quantitative evaluation requires good measurement quality (typically better than that available from current measurements). Therefore, we introduce an iterative retrieval algorithm correcting for the higher-order absorption structures not yet considered in the DOAS fit as well as the absorption dependence on

  10. Spectroscopy, scattering, and KK molecules

    SciTech Connect

    Weinstein, J.

    1994-04-01

    The author presents a pedagogical description of a new theoretical technique, based on the multichannel Schroedinger equation, for simultaneously applying the quark model to both meson spectroscopy and meson-meson scattering. This is an extension of an earlier analysis which led to the prediction that the f{sub o}(975) and a{sub o}(980) scalar mesons are K{bar K} molecular states.

  11. 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.

  12. Resonance light scattering spectroscopy study of interaction between norfloxacin and calf thymus DNA and its analytical application

    NASA Astrophysics Data System (ADS)

    Chen, Zhanguang; Zhang, Taiyu; Han, Yali; Zhu, Li

    2006-11-01

    The interaction between norfloxacin and calf thymus double-stranded DNA (dsDNA) has been studied by a resonance light scattering (RLS) technique with a common spectrofluorometer. The characteristics of RLS spectra, the effective factors and optimum conditions of the reaction have been investigated. In Britton-Robinson (BR) buffer (pH 5.87), norfloxacin has a maximum peak 405.5 nm and the RLS intensity is remarkably enhanced by trace amount of calf thymus dsDNA due to the interaction between norfloxacin and dsDNA. The binding of norfloxacin to DNA forms large particles, which were characterized by RLS spectrum, scanning electron microscopy (SEM), ultraviolet-visible (UV-vis) spectrum, and fluorescence spectrum. Based on the enhanced RLS intensity, a novel method for sensitive determination of calf thymus dsDNA concentration ranging from 0.02 to 2.3 μg ml -1 was developed. The determination limit (3 σ) was 1.2 ng ml -1. The method is simple, rapid, practical and relatively free from interference generated by coexisting substance, as well as much more sensitive than most of the reported methods. Three synthetic samples of ctDNA were determined with satisfactory results.

  13. Liposome-induced DNA compaction and reentrant condensation investigated by dielectric relaxation spectroscopy and dynamic light scattering techniques

    NASA Astrophysics Data System (ADS)

    Zuzzi, S.; Cametti, C.; Onori, G.; Sennato, S.

    2007-07-01

    Interaction of DNA with oppositely charged objects, such as multivalent ions, cationic surfactants, cationic liposomes, basic proteins, and alcohols, up to nano- or mesoscopic particles, gives rise to a very interesting and fascinating phenomenology, where the shape, size, and stability of the resulting aggregates depend on a delicate balance between different driving forces, mainly of electrostatic origin. We have studied the cationic liposome-DNA complexes during the whole complexation process, below, close to, and above the isoelectric condition, where the number of cationic lipids equals the number of phosphate groups on the DNA chain. We took advantage of the combined use of dynamic light scattering, laser Doppler electrophoretic mobility, and radio-wave dielectric relaxation measurements in order to characterize both the structural parameters (hydrodynamic radius) and the electrical parameters (charge and counterion concentration) of the resulting structures. These structures are fundamentally of two types, clusters of liposomes stuck together by DNA chains (cluster phase in low-density colloidal suspension) and coexisting DNA coils and DNA globules, according to the procedure through which interactions occur (liposomes in excess DNA solution or DNA in excess liposome suspension).

  14. Characterization of Sizes of Aggregates of Insulin Analogs and the Conformations of the Constituent Protein Molecules: A Concomitant Dynamic Light Scattering and Raman Spectroscopy Study.

    PubMed

    Zhou, Chen; Qi, Wei; Lewis, E Neil; Carpenter, John F

    2016-02-01

    To generate aggregates, 3 insulin analogs, lispro, aspart, and glulisine, were incubated without phenolic preservatives for 30 days at 37 °C. As a function of incubation time, aggregation was quantified with size exclusion chromatography, and the sizes of aggregates and the conformations of the constituent molecules were characterized with concomitant dynamic light scattering and Raman spectroscopy. During incubation, lispro was progressively converted into soluble aggregates with hydrodynamic diameters of circa 15 nm, and 95% of the native protein had aggregated at day 30. Raman spectroscopy documented that aggregation resulted in conversion of a large fraction of native alpha helix into nonnative beta sheet structure and a distortion of disulfide bonds. In contrast, for aspart and glulisine only 20% of the native proteins aggregated after 30 days, and minimal structural perturbations were detected. In addition, consistent with the relative aggregation rates during isothermal incubation, Raman spectroscopy showed that during heating the onset temperature for secondary structural perturbations of lispro occurred 7 °C-10 °C lower than those for aspart or glulisine. Overall the results of this study demonstrated that-as in the case during formation of amyloid fibrils from insulin-formation of soluble aggregates of lispro resulted in a high level of conversion of alpha helix into beta sheet.

  15. 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.

  16. 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

  17. Binding investigation on the interaction between Methylene Blue (MB)/TiO2 nanocomposites and bovine serum albumin by resonance light-scattering (RLS) technique and fluorescence spectroscopy.

    PubMed

    Li, Yuesheng; Zhang, Yue; Sun, Shaofa; Zhang, Aiqing; Liu, Yi

    2013-11-05

    The interaction between Methylene Blue (MB)/TiO2 nanocomposites and bovine serum albumin (BSA) was investigated by resonance light scattering (RLS), fluorescence, three-dimension spectra and UV-vis absorbance spectroscopy. Several factors which may influence the RLS intensity were also investigated before characterizing MB/TiO2-BSA complex. It was proved that the mechanism of MB/TiO2 nanocomposites binding to BSA was mainly a result of the formation of MB/TiO2-BSA complex. The binding constant of MB/TiO2-BSA is 0.762 × 10(-5) L mol(-1) at 298K. By calculating the binding constant at different temperature, the thermodynamic parameters ΔH, ΔG, and ΔS can be observed and deduced that the hydrophobic interactions played an important role to stabilize the complex. The distance r (3.73 nm) between donor (BSA) and acceptor (MB/TiO2) was obtained according to fluorescence resonance energy transfer (FRET). The binding site for MB/TiO2 on BSA was mainly located in sub-domain IIA. The UV-vis absorbance, circular dichroism and three dimension fluorescence have also been used to investigate the effect of MB/TiO2 on the conformation of BSA.

  18. Ionic liquid containing microemulsions: probe by conductance, dynamic light scattering, diffusion-ordered spectroscopy NMR measurements, and study of solvent relaxation dynamics.

    PubMed

    Pramanik, Rajib; Sarkar, Souravi; Ghatak, Chiranjib; Rao, Vishal Govind; Sarkar, Nilmoni

    2011-03-17

    Room-temperature ionic liquid (RTIL), N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([P(13)][Tf(2)N]), was substituted for polar water and formed nonaqueous microemulsions with benzene by the aid of nonionic surfactant TX-100. The phase behavior of the ternary system was investigated, and microregions of [P(13)][Tf(2)N]-in-benzene (IL/O), bicontinuous, and benzene-in-[P(13)][Tf(2)N] (O/IL) were identified by traditional electrical conductivity measurements. Dynamic light scattering (DLS) revealed the formation of these IL microemulsions because with gradual increase of RTIL contents the droplet sizes of the microemulsions are also gradually increasing. Pulsed-field gradient spin-echo NMR have been studied to measure the diffusion coefficients of neat [P(13)][Tf(2)N] and [P(13)][Tf(2)N] in microemulsions which indicate ionic liquid containing microemulsions is formed. Moreover, the dynamics of solvent relaxation have been investigated in [P(13)][Tf(2)N]/TX100/benzene microemulsions using steady-state and time-resolved fluorescence spectroscopy using coumarin 153 (C-153) and coumarin 480 (C-480) fluorescence probe with variation of RTIL contents in microemulsions. For both of the probes with increasing amount of ionic liquids in microemulsions the relative contribution of the fast components increases and the slow components contribution decreases; therefore the average solvation time decreases.

  19. Noise autocorrelation spectroscopy with coherent Raman scattering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoji G.; Konorov, Stanislav O.; Hepburn, John W.; Milner, Valery

    2008-02-01

    Coherent anti-Stokes Raman scattering (CARS) with femtosecond laser pulses has become a widespread method in nonlinear optical spectroscopy and microscopy. As a third-order nonlinear process, femtosecond CARS exhibits high efficiency at low average laser power. High sensitivity to molecular structure enables detection of small quantities of complex molecules and non-invasive biological imaging. Temporal and spectral resolution of CARS is typically limited by the duration of the excitation pulses and their frequency bandwidth, respectively. Broadband femtosecond pulses are advantageous for time-resolved CARS spectroscopy, but offer poor spectral resolution. The latter can be improved by invoking optical or quantum interference at the expense of increasing complexity of instrumentation and susceptibility to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency of a coherent process with the robustness of incoherent light. It does require averaging over different noise realizations, but no temporal scanning or spectral pulse shaping as commonly used by frequency-resolved spectroscopic methods with ultrashort pulses.

  20. Determination of equilibrium and rate constants for complex formation by fluorescence correlation spectroscopy supplemented by dynamic light scattering and Taylor dispersion analysis.

    PubMed

    Zhang, Xuzhu; Poniewierski, Andrzej; Jelińska, Aldona; Zagożdżon, Anna; Wisniewska, Agnieszka; Hou, Sen; Hołyst, Robert

    2016-10-04

    The equilibrium and rate constants of molecular complex formation are of great interest both in the field of chemistry and biology. Here, we use fluorescence correlation spectroscopy (FCS), supplemented by dynamic light scattering (DLS) and Taylor dispersion analysis (TDA), to study the complex formation in model systems of dye-micelle interactions. In our case, dyes rhodamine 110 and ATTO-488 interact with three differently charged surfactant micelles: octaethylene glycol monododecyl ether C12E8 (neutral), cetyltrimethylammonium chloride CTAC (positive) and sodium dodecyl sulfate SDS (negative). To determine the rate constants for the dye-micelle complex formation we fit the experimental data obtained by FCS with a new form of the autocorrelation function, derived in the accompanying paper. Our results show that the association rate constants for the model systems are roughly two orders of magnitude smaller than those in the case of the diffusion-controlled limit. Because the complex stability is determined by the dissociation rate constant, a two-step reaction mechanism, including the diffusion-controlled and reaction-controlled rates, is used to explain the dye-micelle interaction. In the limit of fast reaction, we apply FCS to determine the equilibrium constant from the effective diffusion coefficient of the fluorescent components. Depending on the value of the equilibrium constant, we distinguish three types of interaction in the studied systems: weak, intermediate and strong. The values of the equilibrium constant obtained from the FCS and TDA experiments are very close to each other, which supports the theoretical model used to interpret the FCS data.

  1. 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.

  2. The light meson spectroscopy program

    SciTech Connect

    Smith, Elton S.

    2014-06-01

    Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

  3. 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.

  4. Broadband enhanced backscattering spectroscopy of strongly scattering media.

    PubMed

    Muskens, O L; Lagendijk, A

    2008-01-21

    We report on a new experimental method for enhanced backscattering spectroscopy (EBS) of strongly scattering media over a bandwidth from 530-1000 nm. The instrument consists of a supercontinuum light source and an angle-dependent detection system using a fiber-coupled grating spectrometer. Using a combination of two setups, the backscattered intensity is obtained over a large angular range and using circularly polarized light. We present broadband EBS of a TiO(2) powder and of a strongly scattering porous GaP layer. In combination with theoretical model fits, the EBS system yields the optical transport mean free path over the available spectral window.

  5. Light distribution modulated diffuse reflectance spectroscopy

    PubMed Central

    Huang, Pin-Yuan; Chien, Chun-Yu; Sheu, Chia-Rong; Chen, Yu-Wen; Tseng, Sheng-Hao

    2016-01-01

    Typically, a diffuse reflectance spectroscopy (DRS) system employing a continuous wave light source would need to acquire diffuse reflectances measured at multiple source-detector separations for determining the absorption and reduced scattering coefficients of turbid samples. This results in a multi-fiber probe structure and an indefinite probing depth. Here we present a novel DRS method that can utilize a few diffuse reflectances measured at one source-detector separation for recovering the optical properties of samples. The core of innovation is a liquid crystal (LC) cell whose scattering property can be modulated by the bias voltage. By placing the LC cell between the light source and the sample, the spatial distribution of light in the sample can be varied as the scattering property of the LC cell modulated by the bias voltage, and this would induce intensity variation of the collected diffuse reflectance. From a series of Monte Carlo simulations and phantom measurements, we found that this new light distribution modulated DRS (LDM DRS) system was capable of accurately recover the absorption and scattering coefficients of turbid samples and its probing depth only varied by less than 3% over the full bias voltage variation range. Our results suggest that this LDM DRS platform could be developed to various low-cost, efficient, and compact systems for in-vivo superficial tissue investigation. PMID:27375931

  6. Light distribution modulated diffuse reflectance spectroscopy.

    PubMed

    Huang, Pin-Yuan; Chien, Chun-Yu; Sheu, Chia-Rong; Chen, Yu-Wen; Tseng, Sheng-Hao

    2016-06-01

    Typically, a diffuse reflectance spectroscopy (DRS) system employing a continuous wave light source would need to acquire diffuse reflectances measured at multiple source-detector separations for determining the absorption and reduced scattering coefficients of turbid samples. This results in a multi-fiber probe structure and an indefinite probing depth. Here we present a novel DRS method that can utilize a few diffuse reflectances measured at one source-detector separation for recovering the optical properties of samples. The core of innovation is a liquid crystal (LC) cell whose scattering property can be modulated by the bias voltage. By placing the LC cell between the light source and the sample, the spatial distribution of light in the sample can be varied as the scattering property of the LC cell modulated by the bias voltage, and this would induce intensity variation of the collected diffuse reflectance. From a series of Monte Carlo simulations and phantom measurements, we found that this new light distribution modulated DRS (LDM DRS) system was capable of accurately recover the absorption and scattering coefficients of turbid samples and its probing depth only varied by less than 3% over the full bias voltage variation range. Our results suggest that this LDM DRS platform could be developed to various low-cost, efficient, and compact systems for in-vivo superficial tissue investigation.

  7. 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.

  8. 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.

  9. 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.

  10. 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).

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Pathlength Determination for Gas in Scattering Media Absorption Spectroscopy

    PubMed Central

    Mei, Liang; Somesfalean, Gabriel; Svanberg, Sune

    2014-01-01

    Gas in scattering media absorption spectroscopy (GASMAS) has been extensively studied and applied during recent years in, e.g., food packaging, human sinus monitoring, gas diffusion studies, and pharmaceutical tablet characterization. The focus has been on the evaluation of the gas absorption pathlength in porous media, which a priori is unknown due to heavy light scattering. In this paper, three different approaches are summarized. One possibility is to simultaneously monitor another gas with known concentration (e.g., water vapor), the pathlength of which can then be obtained and used for the target gas (e.g., oxygen) to retrieve its concentration. The second approach is to measure the mean optical pathlength or physical pathlength with other methods, including time-of-flight spectroscopy, frequency-modulated light scattering interferometry and the frequency domain photon migration method. By utilizing these methods, an average concentration can be obtained and the porosities of the material are studied. The last method retrieves the gas concentration without knowing its pathlength by analyzing the gas absorption line shape, which depends upon the concentration of buffer gases due to intermolecular collisions. The pathlength enhancement effect due to multiple scattering enables also the use of porous media as multipass gas cells for trace gas monitoring. All these efforts open up a multitude of different applications for the GASMAS technique. PMID:24573311

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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…

  4. 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

  5. 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)

  6. 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.

  7. 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.

  8. 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.

  9. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    NASA Astrophysics Data System (ADS)

    Remer, Itay; Bilenca, Alberto

    2016-09-01

    We demonstrate a high-speed stimulated Brillouin scattering (SBS) spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (˜25 dB in water samples and ˜15 dB in tissue phantoms). These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  10. Polarization-controlled optimal scatter suppression in transient absorption spectroscopy

    PubMed Central

    Malý, Pavel; Ravensbergen, Janneke; Kennis, John T. M.; van Grondelle, Rienk; Croce, Roberta; Mančal, Tomáš; van Oort, Bart

    2017-01-01

    Ultrafast transient absorption spectroscopy is a powerful technique to study fast photo-induced processes, such as electron, proton and energy transfer, isomerization and molecular dynamics, in a diverse range of samples, including solid state materials and proteins. Many such experiments suffer from signal distortion by scattered excitation light, in particular close to the excitation (pump) frequency. Scattered light can be effectively suppressed by a polarizer oriented perpendicular to the excitation polarization and positioned behind the sample in the optical path of the probe beam. However, this introduces anisotropic polarization contributions into the recorded signal. We present an approach based on setting specific polarizations of the pump and probe pulses, combined with a polarizer behind the sample. Together, this controls the signal-to-scatter ratio (SSR), while maintaining isotropic signal. We present SSR for the full range of polarizations and analytically derive the optimal configuration at angles of 40.5° between probe and pump and of 66.9° between polarizer and pump polarizations. This improves SSR by (or compared to polarizer parallel to probe). The calculations are validated by transient absorption experiments on the common fluorescent dye Rhodamine B. This approach provides a simple method to considerably improve the SSR in transient absorption spectroscopy. PMID:28262765

  11. Polarization-controlled optimal scatter suppression in transient absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Malý, Pavel; Ravensbergen, Janneke; Kennis, John T. M.; van Grondelle, Rienk; Croce, Roberta; Mančal, Tomáš; van Oort, Bart

    2017-03-01

    Ultrafast transient absorption spectroscopy is a powerful technique to study fast photo-induced processes, such as electron, proton and energy transfer, isomerization and molecular dynamics, in a diverse range of samples, including solid state materials and proteins. Many such experiments suffer from signal distortion by scattered excitation light, in particular close to the excitation (pump) frequency. Scattered light can be effectively suppressed by a polarizer oriented perpendicular to the excitation polarization and positioned behind the sample in the optical path of the probe beam. However, this introduces anisotropic polarization contributions into the recorded signal. We present an approach based on setting specific polarizations of the pump and probe pulses, combined with a polarizer behind the sample. Together, this controls the signal-to-scatter ratio (SSR), while maintaining isotropic signal. We present SSR for the full range of polarizations and analytically derive the optimal configuration at angles of 40.5° between probe and pump and of 66.9° between polarizer and pump polarizations. This improves SSR by (or compared to polarizer parallel to probe). The calculations are validated by transient absorption experiments on the common fluorescent dye Rhodamine B. This approach provides a simple method to considerably improve the SSR in transient absorption spectroscopy.

  12. 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.

  13. 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.

  14. Resolving the electromagnetic mechanism of surface-enhanced light scattering at single hot spots

    PubMed Central

    Alonso-González, P.; Albella, P.; Schnell, M.; Chen, J.; Huth, F.; García-Etxarri, A.; Casanova, F.; Golmar, F.; Arzubiaga, L.; Hueso, L.E.; Aizpurua, J.; Hillenbrand, R.

    2012-01-01

    Light scattering at nanoparticles and molecules can be dramatically enhanced in the 'hot spots' of optical antennas, where the incident light is highly concentrated. Although this effect is widely applied in surface-enhanced optical sensing, spectroscopy and microscopy, the underlying electromagnetic mechanism of the signal enhancement is challenging to trace experimentally. Here we study elastically scattered light from an individual object located in the well-defined hot spot of single antennas, as a new approach to resolve the role of the antenna in the scattering process. We provide experimental evidence that the intensity elastically scattered off the object scales with the fourth power of the local field enhancement provided by the antenna, and that the underlying electromagnetic mechanism is identical to the one commonly accepted in surface-enhanced Raman scattering. We also measure the phase shift of the scattered light, which provides a novel and unambiguous fingerprint of surface-enhanced light scattering. PMID:22353715

  15. 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.

  16. IR spectroscopy vs. Raman scattering by measurement of glucose concentration

    NASA Astrophysics Data System (ADS)

    Abdallah, O.; Hansmann, J.; Bolz, A.; Mertsching, H.

    2010-11-01

    By developing a non-invasive device for glucose concentration measurement, two promising methods were compared for that aim. The Raman scattering using Laser at the wavelength 785 nm and the light scattering in R- and IR-range are demonstrated. An easy accessible and low-cost method for glucose concentration monitoring and management to avoid its complications will be a great help for diabetic patients. Raman Scattering is a promising method for noninvasively measuring of glucose and for the diagnostic of pathological tissue variations. Despite the power and the time of measurement can be reduced using enhanced Raman scattering, it will be difficult to develop a compatible device with low power Laser and low price for a non-invasive method for home monitoring. As using IR-spectroscopy at wavelengths slightly below 10000 nm, the absorption of glucose can be well discriminated from that of water, LED`s or LD's at these wavelengths are very expensive for this purpose. At wavelengths about 6250 and 7700 glucose has a less light absorption than water. Also slightly above 3000 nm glucose has a high absorption. There are also possibilities for the measurement in the NIR at wavelengths between 1400 nm and 1670 nm. Scattering measurements at wavelengths below 900 nm and our measurements with the wavelength about 640 nm give reproducible glucose dependence on the reflected light from a glucose solution at a constant temperature. A multi-sensor with different wavelengths and temperature sensor will be a good choice for in-vivo glucose monitoring.

  17. 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...

  18. 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.

  19. 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.

  20. Ripplon scattering using grating heterodyne spectroscopy

    NASA Technical Reports Server (NTRS)

    Sirohi, R. S.; Edwards, R. V.; Mann, J. A., Jr.

    1980-01-01

    Heterodyne photon spectroscopy was used for the study of the viseo-elastic properties of the liquid interface by studying the scattering from thermal ripplons. A theory of a heterodyne apparatus based on a grating is presented, and the heterodyne condition is given in terms of the parameters of the experimental set-up. Emphasis was placed on the study of the instrumental function and its influence on the measurement data. The instrumental function is not always gaussian, but its functional form depends on the parameters of the experimental set-up. An algorithm is suggested to arrive at the center frequency and half width at half height of the spectrum from the noisy experimental data, and applied to the measurement data obtained from ethanol and water surfaces.

  1. 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.

  2. 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).

  3. Optical absorption and scattering spectroscopies of single nano-objects.

    PubMed

    Crut, Aurélien; Maioli, Paolo; Del Fatti, Natalia; Vallée, Fabrice

    2014-06-07

    Developments of optical detection and spectroscopy methods for single nano-objects are key advances for applications and fundamental understanding of the novel properties exhibited by nanosize systems. These methods are reviewed, focusing on far-field optical approaches based on light absorption and elastic scattering. The principles of the main linear and nonlinear methods are described and experimental results are illustrated in the case of metal nanoparticles, stressing the key role played by the object environment, such as the presence of a substrate, bound surface molecules or other nano-objects. Special attention is devoted to quantitative methods and correlation of the measured optical spectra of a nano-object with its morphology, characterized either optically or by electron microscopy, as this permits precise comparison with theoretical models. Application of these methods to optical detection and spectroscopy for single semiconductor nanowires and carbon nanotubes is also presented. Extension to ultrafast nonlinear extinction or scattering spectroscopies of single nano-objects is finally discussed in the context of investigation of their nonlinear optical response and their electronic, acoustic and thermal properties.

  4. Dynamic light scattering and optical absorption spectroscopy study of pH and temperature stabilities of the extracellular hemoglobin of Glossoscolex paulistus.

    PubMed

    Santiago, Patrícia S; Moura, Franciane; Moreira, Leonardo M; Domingues, Marco M; Santos, Nuno C; Tabak, Marcel

    2008-03-15

    The extracellular hemoglobin of Glossoscolex paulistus (HbGp) is constituted of subunits containing heme groups, monomers and trimers, and nonheme structures, called linkers, and the whole protein has a minimum molecular mass near 3.1 x 10(6) Da. This and other proteins of the same family are useful model systems for developing blood substitutes due to their extracellular nature, large size, and resistance to oxidation. HbGp samples were studied by dynamic light scattering (DLS). In the pH range 6.0-8.0, HbGp is stable and has a monodisperse size distribution with a z-average hydrodynamic diameter (D(h)) of 27 +/- 1 nm. A more alkaline pH induced an irreversible dissociation process, resulting in a smaller D(h) of 10 +/- 1 nm. The decrease in D(h) suggests a complete hemoglobin dissociation. Gel filtration chromatography was used to show unequivocally the oligomeric dissociation observed at alkaline pH. At pH 9.0, the dissociation kinetics is slow, taking a minimum of 24 h to be completed. Dissociation rate constants progressively increase at higher pH, becoming, at pH 10.5, not detectable by DLS. Protein temperature stability was also pH-dependent. Melting curves for HbGp showed oligomeric dissociation and protein denaturation as a function of pH. Dissociation temperatures were lower at higher pH. Kinetic studies were also performed using ultraviolet-visible absorption at the Soret band. Optical absorption monitors the hemoglobin autoxidation while DLS gives information regarding particle size changes in the process of protein dissociation. Absorption was analyzed at different pH values in the range 9.0-9.8 and at two temperatures, 25 degrees C and 38 degrees C. At 25 degrees C, for pH 9.0 and 9.3, the kinetics monitored by ultraviolet-visible absorption presents a monoexponential behavior, whereas for pH 9.6 and 9.8, a biexponential behavior was observed, consistent with heme heterogeneity at more alkaline pH. The kinetics at 38 degrees C is faster than that at

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Spectral analysis of scattered light from flowers' petals

    NASA Astrophysics Data System (ADS)

    Ozawa, Atsumi; Uehara, Tomomi; Sekiguchi, Fumihiko; Imai, Hajime

    2009-07-01

    A new method was developed for studying absorption characteristics of opaque samples based on the light scattering spectroscopy. Measurements were made in white, red and violet petals of Petunia hybrida, and gave the absorption spectra in a non-destructive manner without damaging the cell structures of the petal. The red petal has absorption peak at 550 nm and the violet has three absorption peaks: at 450, 670, and 550 nm. The results were discussed in correlation with the microscopic cell structures of the petal observed with optical microscope and transmission electron microscopy (TEM). Only the cells placed in the surface have the pigments giving the color of the petal.

  15. Multiple-scattering effects in lidar spectroscopy

    NASA Astrophysics Data System (ADS)

    Joelson, Brad D.; Kattawar, George W.

    1996-11-01

    We have performed Monte Carlo calculations to investigate the effect of multiple scattering on the frequency spectra due to Brillouin scattering in the ocean. The use of the frequency spectra to determine the speed of sound and temperature profiles and the hydrosol backscattering probability is shown to be stable in turbid multiple scattering waters.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Detection of circular polarization in light scattered from photosynthetic microbes

    PubMed Central

    Sparks, William B.; Hough, James; Germer, Thomas A.; Chen, Feng; DasSarma, Shiladitya; DasSarma, Priya; Robb, Frank T.; Manset, Nadine; Kolokolova, Ludmilla; Reid, Neill; Macchetto, F. Duccio; Martin, William

    2009-01-01

    The identification of a universal biosignature that could be sensed remotely is critical to the prospects for success in the search for life elsewhere in the universe. A candidate universal biosignature is homochirality, which is likely to be a generic property of all biochemical life. Because of the optical activity of chiral molecules, it has been hypothesized that this unique characteristic may provide a suitable remote sensing probe using circular polarization spectroscopy. Here, we report the detection of circular polarization in light scattered by photosynthetic microbes. We show that the circular polarization appears to arise from circular dichroism of the strong electronic transitions of photosynthetic absorption bands. We conclude that circular polarization spectroscopy could provide a powerful remote sensing technique for generic life searches. PMID:19416893

  3. 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

  4. 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.

  5. Doppler optical mixing spectroscopy in multiparticle scattering fluids

    SciTech Connect

    Dubnishchev, Yu N

    2011-03-31

    We discuss the basic scheme of laser Doppler optical mixing spectroscopy for the analysis of media with multiparticle scattering. It is shown that the Rayleigh scheme, in contrast to the heterodyne and differential schemes, is insensitive to the effects of multiparticle scattering. (laser applications and other aspects of quantum electronics)

  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. 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.

  8. 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.

  9. Modeling of light scattering by icy bodies

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  10. 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.

  11. 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…

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. In-line interferometric femtosecond stimulated Raman scattering spectroscopy.

    PubMed

    Dobner, Sven; Groß, Petra; Fallnich, Carsten

    2013-06-28

    We present in-line interferometric femtosecond stimulated Raman scattering (II-FSRS), a new method to measure the spectral Raman intensity and phase over a broad spectral range, potentially in a single shot. An analytic model is developed, that excellently reproduces the measured spectra. Additionally, the performance of II-FSRS is directly compared in experiments to two established techniques, namely femtosecond stimulated Raman scattering and femtosecond Raman induced Kerr-effect spectroscopy.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Correlating the morphological and light scattering properties of biological cells

    NASA Astrophysics Data System (ADS)

    Moran, Marina

    The scattered light pattern from a biological cell is greatly influenced by the internal structure and optical properties of the cell. This research project examines the relationships between the morphological and scattering properties of biological cells through numerical simulations. The mains goals are: (1) to develop a procedure to analytically model biological cells, (2) to quantitatively study the effects of a range of cell characteristics on the features of the light scattering patterns, and (3) to classify cells based on the features of their light scattering patterns. A procedure to create an analytical cell model was developed which extracted structural information from the confocal microscopic images of cells and allowed for the alteration of the cell structure in a controlled and systematic way. The influence of cell surface roughness, nuclear size, and mitochondrial volume density, spatial distribution, size and shape on the light scattering patterns was studied through numerical simulations of light scattering using the Discrete Dipole Approximation. It was found that the light scattering intensity in the scattering angle range of 25° to 45° responded to changes in the surface fluctuation of the cell and the range of 90° to 110° was well suited for characterization of mitochondrial density and nuclear size. A comparison of light scattering pattern analysis methods revealed that the angular distribution of the scattered light and Gabor filters were most helpful in differentiating between the cell characteristics. In addition, a measured increase in the Gabor energy of the light scattering patterns in response to an increase in the complexity of the cell models suggested that a complex nuclear structure and mitochondria should be included when modeling biological cells for light scattering simulations. Analysis of the scattering pattern features with Gabor filters resulted in discrimination of the cell models according to cell surface roughness

  16. Observations of stimulated Raman scattering using simultaneous Thomson scattering, fast electron spectroscopy, and infrared diagnostics

    SciTech Connect

    McIntosh, G.; Meyer, J.; Yazhou, Z.

    1986-10-01

    Stimulated Raman scattering (SRS) in a CO/sub 2/ laser(lambda/sub 0/ -- 10.6 ..mu..m) produced plasma has been studied experimentally. The enhanced electron plasma wave (epw) fluctuations observed with ruby laser Thomson scattering have been compared with the scattered infrared (IR) spectra and the high-energy (near 100 keV) electrons. No scattered IR light in the range 1.5lambda/sub 0/ light in this range. A signal was detected at 2lambda/sub 0/ which is due to the two plasmon decay instability. The number and energy spectra of the fast electrons are well correlated with the Thomson scattered wave vector spectra.

  17. Measurements and interpretations of light scattering from intact biological cells

    NASA Astrophysics Data System (ADS)

    Wilson, Jeremy D.

    Visible light interacts with biological cells primarily through elastic scattering. The details of how cells scatter light depend on their morphology and their substructures. In this thesis we first present a series of experiments and models to discern the specific contributions of certain sub-cellular constituents to whole-cell scattering. Exploiting the findings of those studies, we report on experiments within model systems of cell death that demonstrate the potential of light scattering measurements as a tool in modern biology. Instrumentation capable of exploiting the findings of this thesis from a biology-relevant microscopy platform is designed and developed. A Mie theory based interpretation of light scattering signals originating from a collection of particles with a broad size distribution is developed. Upon applying this model to scattering data from intact cells, we find that it robustly extracts the size scale of dominant light scattering particles, suggests that scattering measurements are sensitive primarily to mitochondrial and lysosomal morphology, and unites conflicting results in the literature. Using this model as a basis, we present a collection of studies in which we use various strategies of photodynamic therapy (PDT) as a biophysical tool to perturb mitochondria and lysosomes, and observe the effects of these perturbations on whole-cell scattering. Through these experiments, we are able to discern the individual contributions of mitochondria and lysosomes to whole-cell light scattering, and demonstrate that mitochondria are responsible for roughly 80% of the scattering signal. Results of experiments aimed at demonstrating the potential role that light scattering measurements have to play in future studies of cell death biology are presented. We first show that mitochondrial-PDT-induced morphology changes measured with light scattering map into the cell killing efficacy of the therapy. We next demonstrate that mitochondrial

  18. 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.

  19. White light spectroscopy for free flap monitoring.

    PubMed

    Fox, Paige M; Zeidler, Kamakshi; Carey, Joseph; Lee, Gordon K

    2013-03-01

    White light spectroscopy non-invasively measures hemoglobin saturation at the capillary level rendering an end-organ measurement of perfusion. We hypothesized this technology could be used after microvascular surgery to allow for early detection of ischemia and thrombosis. The Spectros T-Stat monitoring device, which utilizes white light spectroscopy, was compared with traditional flap monitoring techniques including pencil Doppler and clinical exam. Data were prospectively collected and analyzed. Results from 31 flaps revealed a normal capillary hemoglobin saturation of 40-75% with increase in saturation during the early postoperative period. One flap required return to the operating room 12 hours after microvascular anastomosis. The T-stat system recorded an acute decrease in saturation from ~50% to less than 30% 50 min prior to identification by clinical exam. Prompt treatment resulted in flap salvage. The Spectros T-Stat monitor may be a useful adjunct for free flap monitoring providing continuous, accurate perfusion assessment postoperatively.

  20. Visible light optical coherence correlation spectroscopy.

    PubMed

    Broillet, Stephane; Szlag, Daniel; Bouwens, Arno; Maurizi, Lionel; Hofmann, Heinrich; Lasser, Theo; Leutenegger, Marcel

    2014-09-08

    Optical coherence correlation spectroscopy (OCCS) allows studying kinetic processes at the single particle level using the backscattered light of nanoparticles. We extend the possibilities of this technique by increasing its signal-to-noise ratio by a factor of more than 25 and by generalizing the method to solutions containing multiple nanoparticle species. We applied these improvements by measuring protein adsorption and formation of a protein monolayer on superparamagnetic iron oxide nanoparticles under physiological conditions.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Shining light on neurosurgery diagnostics using Raman spectroscopy.

    PubMed

    Broadbent, Brandy; Tseng, James; Kast, Rachel; Noh, Thomas; Brusatori, Michelle; Kalkanis, Steven N; Auner, Gregory W

    2016-10-01

    Surgical excision of brain tumors provides a means of cytoreduction and diagnosis while minimizing neurologic deficit and improving overall survival. Despite advances in functional and three-dimensional stereotactic navigation and intraoperative magnetic resonance imaging, delineating tissue in real time with physiological confirmation is challenging. Raman spectroscopy is a promising investigative and diagnostic tool for neurosurgery, which provides rapid, non-destructive molecular characterization in vivo or in vitro for biopsy, margin assessment, or laboratory uses. The Raman Effect occurs when light temporarily changes a bond's polarizability, causing change in the vibrational frequency, with a corresponding change in energy/wavelength of the scattered photon. The recorded inelastic scattering results in a "fingerprint" or Raman spectrum of the constituent under investigation. The amount, location, and intensity of peaks in the fingerprint vary based on the amount of vibrational bonds in a molecule and their ensemble interactions with each other. Distinct differences between various pathologic conditions are shown as different intensities of the same peak, or shifting of a peak based on the binding conformation. Raman spectroscopy has potential for integration into clinical practice, particularly in distinguishing normal and diseased tissue as an adjunct to standard pathologic diagnosis. Further, development of fiber-optic Raman probes that fit through the instrument port of a standard endoscope now allows researchers and clinicians to utilize spectroscopic information for evaluation of in vivo tissue. This review highlights the need for such an instrument, summarizes neurosurgical Raman work performed to date, and discusses the future applications of neurosurgical Raman spectroscopy.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Interferometric background reduction for femtosecond stimulated Raman scattering loss spectroscopy.

    PubMed

    Dobner, Sven; Cleff, Carsten; Fallnich, Carsten; Groß, Petra

    2012-11-07

    We present a purely optical method for background suppression in nonlinear spectroscopy based on linear interferometry. Employing an unbalanced Sagnac interferometer, an unprecedented background reduction of 17  dB over a broad bandwidth of 60  THz (2000  cm(-1)) is achieved and its application to femtosecond stimulated Raman scattering loss spectroscopy is demonstrated. Apart from raising the signal-to-background ratio in the measurement of the Raman intensity spectrum, this interferometric method grants access to the spectral phase of the resonant χ(3) contribution. The spectral phase becomes apparent as a dispersive lineshape and is reproduced numerically with a simple oscillator model.

  12. 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.

  13. Light-echo spectroscopy of historic Supernovae

    NASA Astrophysics Data System (ADS)

    Krause, Oliver

    Young Galactic supernova remnants are unique laboratories for supernova physics. Due to their proximity they provide us with the most detailed view of the outcome of a supernova. However, the exact spectroscopic types of their original explosions have been undetermined so far -hindering to link the wealth of multi-wavelength knowledge about their remnants with the diverse population of supernovae. Light echoes, reflektions of the brilliant supernova burst of light by interstellar dust, provide a unique opportunity to reobserve today -with powerful scientific instruments of the 21st century -historic supernova exlosions even after hundreds of years and to conclude on their nature. We report on optical light-echo spectroscopy of two famous Galactic supernovae: Tycho Brahe's SN 1572 and the supernova that created the Cassiopeia A remnant around the year 1680. These observations finally recovered the missing spectroscopic classifications and provide new constraints on explosion models for future studies.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Influence of multiple scattering effects on in vivo NIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Du, Chongwu; Nahm, Werner

    1995-01-01

    On the basis of both homogeneous and layered skin models this paper analyzes the influences of multiple scattering of skin on the measurements of NIR spectroscopy. Emphasis is laid on the wavelengths of 660, 805, and 940 nm which are used in clinical monitoring systems. The results of Monte-Carlo simulation show that the overwhelming scattering of tissue leads to a nonlinearity in the Lambert-Beer's relation between optical density and chromophore concentration. The consequences of this effect shall be discussed using as an example the non invasive measurement of Indocyanine Green (ICG) in the blood. In this case the multiple scattering of skin causes substantial non-linear relation between the optical density at 805 nm and the concentration of an injected NIR dye in the blood if the concentration of ICG exceeds 10 mg/l. This leads to a significant distortion of the ICG clearance curve and in consequence to a systematic error in the determination of physiological parameters. For multi-wavelength spectroscopy the wavelength dependency of scattering coefficients has to be noticed. The consequence of this effect is demonstrated for blood oxygen saturation (SaO2) measurements.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. Squeezed-light spin noise spectroscopy

    NASA Astrophysics Data System (ADS)

    Lucivero, Vito Giovanni; Jiménez-Martínez, Ricardo; Kong, Jia; Mitchell, Morgan W.

    2016-05-01

    We report quantum enhancement of Faraday rotation spin noise spectroscopy by polarization squeezing of the probe beam. Using natural abundance Rb in 100 Torr of N2 buffer gas and squeezed light from a subthreshold optical parametric oscillator stabilized 20 GHz to the blue of the D1 resonance, we observe that an input squeezing of 3.0 dB improves the signal-to-noise ratio by 1.5 to 2.6 dB over the combined (power)⊗(number density) ranges (0.5-4.0 mW)⊗(1.5 ×1012cm-3 to 1.3 ×1013 cm-3), covering the ranges used in optimized spin noise spectroscopy experiments. We also show that squeezing improves the tradeoff between statistical sensitivity and broadening effects, a previously unobserved quantum advantage.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.

    1998-01-01

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

  13. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Excited light meson spectroscopy from lattice QCD

    SciTech Connect

    Christopher Thomas, Hadron Spectrum Collaboration

    2012-04-01

    I report on recent progress in calculating excited meson spectra using lattice QCD, emphasizing results and phenomenology. With novel techniques we can now extract extensive spectra of excited mesons with high statistical precision, including spin-four states and those with exotic quantum numbers. As well as isovector meson spectra, I will present new calculations of the spectrum of excited light isoscalar mesons, something that has up to now been a challenge for lattice QCD. I show determinations of the flavor content of these mesons, including the eta-eta' mixing angle, providing a window on annihilation dynamics in QCD. I will also discuss recent work on using lattice QCD to map out the energy-dependent phase shift in pi-pi scattering and future applications of the methodology to the study of resonances and decays.

  7. Local Measurement of Flap Oxygen Saturation: An Application of Visible Light Spectroscopy.

    PubMed

    Nasseri, Nassim; Kleiser, Stefan; Reidt, Sascha; Wolf, Martin

    2016-01-01

    The aim was to develop and test a new device (OxyVLS) to measure tissue oxygen saturation by visible light spectroscopy independently of the optical pathlength and scattering. Its local applicability provides the possibility of real time application in flap reconstruction surgery. We tested OxyVLS in a liquid phantom with optical properties similar to human tissue. Our results were in good agreement with a conventional near infrared spectroscopy device.

  8. 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.

  9. 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.

  10. 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)

  11. 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.

  12. Inferring mixture Gibbs free energies from static light scattering data

    NASA Astrophysics Data System (ADS)

    Ross, David; Wahle, Christopher; Thurston, George

    We describe a light scattering partial differential equation for the free energy of mixing that applies to connected, isotropic ternary and quaternary liquid composition domains, including restricted domains which may not touch all binary axes. For restricted domains, contrasting light scattering efficiency patterns obtained at different wavelengths can correspond to the same underlying free energy, and supplement the available information. We discuss well-posed problems for this fully nonlinear, degenerate elliptic partial differential equation. Using Monte Carlo simulations, we provide estimates of the overall system measurement time and sample spacing needed to determine the free energy to a desired degree of accuracy, and indicate how measurement time depends on instrument throughput. These methods provide a way to use static light scattering to measure, directly, mixing free energies of many systems that contain liquid domains. Supported by NIH EY018249.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. High sensitivity gas spectroscopy of porous, highly scattering solids.

    PubMed

    Svensson, Tomas; Andersson, Mats; Rippe, Lars; Johansson, Jonas; Folestad, Staffan; Andersson-Engels, Stefan

    2008-01-01

    We present minimalistic and cost-efficient instrumentation employing tunable diode laser gas spectroscopy for the characterization of porous and highly scattering solids. The sensitivity reaches 3 x 10(-6) (absorption fraction), and the improvement with respect to previous work in this field is a factor of 10. We also provide the first characterization of the interference phenomenon encountered in high-resolution spectroscopy of turbid samples. Revealing that severe optical interference originates from the samples, we discuss important implications for system design. In addition, we introduce tracking coils and sample rotation as new and efficient tools for interference suppression. The great value of the approach is illustrated in an application addressing structural properties of pharmaceutical materials.

  18. Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)

    SciTech Connect

    Rest, A; Welch, D L; Suntzeff, N B; Oaster, L; Lanning, H; Olsen, K; Smith, R C; Becker, A C; Bergmann, M; Challis, P; Clocchiatti, A; Cook, K H; Damke, G; Garg, A; Huber, M E; Matheson, T; Minniti, D; Prieto, J L; Wood-Vasey, W M

    2008-05-06

    We report the discovery of an extensive system of scattered light echo arclets associated with the recent supernovae in the local neighborhood of the Milky Way: Tycho (SN 1572) and Cassiopeia A. Existing work suggests that the Tycho SN was a thermonuclear explosion while the Cas A supernova was a core collapse explosion. Precise classifications according to modern nomenclature require spectra of the outburst light. In the case of ancient SNe, this can only be done with spectroscopy of their light echo, where the discovery of the light echoes from the outburst light is the first step. Adjacent light echo positions suggest that Cas A and Tycho may share common scattering dust structures. If so, it is possible to measure precise distances between historical Galactic supernovae. On-going surveys that alert on the development of bright scattered-light echo features have the potential to reveal detailed spectroscopic information for many recent Galactic supernovae, both directly visible and obscured by dust in the Galactic plane.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Manipulation and spectroscopy of a single particle by use of white-light optical tweezers

    NASA Astrophysics Data System (ADS)

    Li, Peng; Shi, Kebin; Liu, Zhiwen

    2005-01-01

    We demonstrate, for the first time to our knowledge, three-dimensional (3D) trapping and manipulation of microscopic objects by use of supercontinuum white light generated from photonic crystal fibers. Furthermore, we show that the supercontinuum white-light optical tweezers used have the unique capability to perform optical scattering spectroscopy of a single 3D trapped object over a broad wavelength range. These novel tweezers can potentially open a promising avenue toward simultaneous manipulation and characterization of microscopic objects.

  7. 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.

  8. 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.

  9. 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.

  10. Light-Meson Spectroscopy at Compass

    NASA Astrophysics Data System (ADS)

    Krinner, Fabian

    2017-03-01

    The goal of the Compass experiment at CERN is to study the structure and spectroscopy of hadrons. The two-stage spectrometer has large acceptance and covers a wide kinematic range for charged as well as neutral particles allowing to access a wide range of reactions. Light mesons are studied with negative (mostly π-) and positive (p, π+) hadron beams with a momentum of 190 GeV/c. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV/c)2. The flagship channel is the π-π+π- final state, for which Compass has recorded the currently world's largest data sample. These data not only allow us to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new axial-vector signal, the a1(1420), with unusual properties. The findings are confirmed by the analysis of the π-π0π0 final state.

  11. 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.

  12. 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)

  13. 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

  14. Determination of the cervical transformation zone using elastic-scattering spectroscopy

    SciTech Connect

    Bigio, I.J.; Johnson, T.M.; Mourant, J.R.

    1996-04-01

    Optical measurements of the cervical transformation zone (sometimes referred to as the transition zone) using elastic-scattering spectroscopy, demonstrate sensitivity to the epithelial cell-type differences.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  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. Stimulated X-ray Raman scattering - a critical assessment of the building block of nonlinear X-ray spectroscopy.

    PubMed

    Kimberg, Victor; Sanchez-Gonzalez, Alvaro; Mercadier, Laurent; Weninger, Clemens; Lutman, Alberto; Ratner, Daniel; Coffee, Ryan; Bucher, Maximilian; Mucke, Melanie; Agåker, Marcus; Såthe, Conny; Bostedt, Christoph; Nordgren, Joseph; Rubensson, Jan Erik; Rohringer, Nina

    2016-12-16

    With the invention of femtosecond X-ray free-electron lasers (XFELs), studies of light-induced chemical reaction dynamics and structural dynamics reach a new era, allowing for time-resolved X-ray diffraction and spectroscopy. To ultimately probe coherent electron and nuclear dynamics on their natural time and length scales, coherent nonlinear X-ray spectroscopy schemes have been proposed. In this contribution, we want to critically assess the experimental realisation of nonlinear X-ray spectroscopy at current-day XFEL sources, by presenting first experimental attempts to demonstrate stimulated resonant X-ray Raman scattering in molecular gas targets.

  1. 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.

  2. 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.

  3. Development and Validation of the Light and Spectroscopy Concept Inventory

    ERIC Educational Resources Information Center

    Bardar, Erin M.; Prather, Edward E.; Brecher, Kenneth; Slater, Timothy F.

    2007-01-01

    This article describes the development and validation of the Light and Spectroscopy Concept Inventory (LSCI), a 26-item diagnostic test designed (1) to measure students' conceptual understanding of topics related to light and spectroscopy, and (2) to evaluate the effectiveness of instructional interventions in promoting meaningful learning gains…

  4. 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.

  5. 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.

  6. 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.

  7. Incorporating hydrangea-like titanium dioxide light scatterer with high dye-loading on the photoanode for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Chang, Wei-Chen; Tang, Bing-Hong; Lu, Yen-Wei; Yu, Wan-Chin; Lin, Lu-Yin; Wu, Ren-Jang

    2016-07-01

    The light scattering layer is significant for dye-sensitized solar cells (DSSCs) to harvest incident light more efficiently and excite larger amounts of electrons. Hydrangea-like TiO2 (Hsbnd TiO2) and coral-like TiO2 (Csbnd TiO2) nanostructures are synthesized via a hydrothermal method without using templates. Both of the nanostructures are applied as the light scattering layer for DSSCs with the commercial P90 TiO2 nanoparticles as the dye-adsorbed underlayer in the photoanodes. The DSSC with Hsbnd TiO2 as the light scattering layer achieves a higher light-to-electricity conversion efficiency (η) of 7.50% than those of 6.70% and 6.61% for the cells with Csbnd TiO2 and commercial TiO2 as the light scattering layer, and of 6.41% for the DSSC without a light scattering layer in its photoanode, mainly due to the enhanced photocurrent density through the abundant dye adsorption coupled with the inherent light scattering ability for the former case. The results indicate that not only the importance of the light scattering layer in the photoanode but the morphology of the nanostructure composed of the light scattering layer plays great roles on the light scattering and the dye-adsorbing capabilities. The incident photon-to-current efficiency the electrochemical impedance spectroscopy measurements are also applied to analyze the electrochemical performance of the resulting DSSCs.

  8. 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

  9. 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.

  10. 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

  11. Hierarchical cross-linking in physical alginate gels: a rheological and dynamic light scattering investigation

    NASA Astrophysics Data System (ADS)

    Larobina, Domenico; Cipelletti, Luca

    We investigate the dynamics of alginate gels, an important class of biopolymer-based viscoelastic materials, by combining mechanical tests and non-conventional, time-resolved light scattering methods. Two relaxation modes are observed upon applying a compressive or shear stress. Dynamic light scattering and diffusive wave spectroscopy measurements reveal that these modes are associated with discontinuous rearrangement events that restructure the gel network via anomalous, non-diffusive microscopic dynamics. We show that these dynamics are due to both thermal activation and internal stress stored during gelation and propose a scenario where a hierarchy of cross-links with different life times is responsible for the observed complex behavior. Measurements at various temperatures and sample ages are presented to support this scenario.

  12. Brillouin light scattering from quantized spin waves in micron-size magnetic wires

    NASA Astrophysics Data System (ADS)

    Jorzick, J.; Demokritov, S. O.; Mathieu, C.; Hillebrands, B.; Bartenlian, B.; Chappert, C.; Rousseaux, F.; Slavin, A. N.

    1999-12-01

    An experimental study of spin-wave quantization in arrays of micron-size magnetic Ni80Fe20 wires by means of Brillouin light-scattering spectroscopy is reported. Dipolar-dominated Damon-Eshbach spin-wave modes laterally quantized in a single wire with quantized wave vector values determined by the width of the wire are studied. The frequency splitting between quantized modes, which decreases with increasing mode number, depends on the wire sizes and is up to 1.5 GHz. The transferred wave vector interval, where each mode is observed, is calculated using a light-scattering theory for confined geometries. The frequencies of the modes are calculated, taking into account finite-size effects. The results of the calculations are in a good agreement with the experimental data.

  13. The Intermediate Scattering Function in Fluorescence Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Guerra, Rodrigo; Andrews, Ballard; Sen, Pabitra

    2006-03-01

    We formulate the autocorrelation function for Fluorescence Correlation Spectroscopy (FCS) GD(τ) in reciprocal space in terms of the of the Intermediate Scattering Function ISF(k,t) and the fourier transform of the Optical Response Function ORF(k). In this way we may extend the use of FCS to processes that have been studied using NMR, DLS, and neutron scattering. This formalism is useful for the complicated propagators involved in confined systems and in the study of diffusion in cells: where diffusion is either restricted or permeation through membrane is important. Calculations in k-space produce approximate expressions for the ORF using cumulant expansions that are accurate for small wavevectors. This provides descriptions for longer timescales better suited for studying time-dependent diffusion ISF(k,t)->exp[-tD(t)k^2] and provides a natural separation of contributions from system dynamics and from optical artifacts and aberrations. We will show an explicit derivation of a semi-analytical fit function for free diffusion based on standard electromagnetic analysis of a confocal optical apparatus. This fit function is then used to analyze a representative data set and has no free fit parameters other than the diffusion constant.

  14. 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.

  15. A dynamical light scattering technique and its application in viscoelastic networks in soft matter

    NASA Astrophysics Data System (ADS)

    Sarmiento-Gomez, Erick; Galvan-Miyoshi, Julian Masasue; Castillo, Rolando

    2011-08-01

    In this paper, we present a dynamic light scattering technique using diffusing wave spectroscopy to track the dynamics of colloidal particles embedded in a complex fluid which allows us to obtain structural and dynamical information of a transparent viscoelastic material. Scattered light of a single speckle is detected by a photomultiplier tube and the time correlation function of light intensity is calculated using a temporal average. If the particles can not explore the entire phase space, temporal average and ensemble average are not the same. This is a necessary condition to relate ensemble average from the scattering by many particles to intensity temporal fluctuations. To overcome non-ergodicity for large lag times, a CCD camera is used for the acquisition of the scattered light were pixels form an array of detectors which enables us to perform thousands of simultaneous experiments. In this manner, the time correlation function is obtained directly by taking the ensamble average instead of using a temporal average. For short lag times, the non-ergodicity problem can be avoided by remixing the scattered light coming from the sample by the use of a slowly rotating diffuser disk placed before the collection optics of the photomultiplier tube. This procedure provides a true ensemble-averaged time correlation function over ~ 7-8 decades of time. As an example of the application of this technique, the dynamics of microspheres embedded in cross-linked polymer matrix, namely, an acrylamide-bisacrylamide gel is studied. This polymer network is known to swell or shrink by changing the solvent composition. The description of the arrested dynamics of the microspheres can be obtained, as well as the viscoelastic properties of the polymer network at different cage sizes.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Use of fluorescence signals generated by elastic scattering under monochromatic incident light for determining the scattering efficiencies of various plasmonic nanoparticles.

    PubMed

    Song, Ji Eun; Park, Ji Hoon; La, Ju A; Park, Seyeon; Jeong, Min Kuk; Cho, Eun Chul

    2016-08-07

    We present a route that estimates the scattering/absorption characteristics of plasmonic nanoparticles by using fluorescence and UV-visible spectroscopy. Because elastic scattering of nanoparticles caused by a monochromatic incident light is reflected in fluorescence emission spectra when recording at the excitation wavelength, the scattering intensities at the excitation wavelength during fluorescence emission scans are used to compare the scattering characteristics of various plasmonic nanoparticles under conditions where the extinction values of all of the nanoparticles are kept constant at this wavelength. For the two excitation wavelengths (519 and 560 nm) we investigated, the scattering intensities of spherical gold nanoparticles increase with increasing size (15, 33, 51, 73, and 103 nm in diameter). These results are correlated with the nanoparticles' scattering efficiencies (the ratios of scattering to the extinction cross-sections), which are theoretically calculated in the literature using Mie theory. Then, linear calibration equations at each wavelength are derived to estimate the scattering efficiencies of two Au nanorods, Au nanocages, and spherical Ag nanoparticles (15, 25, 37, and 62 nm). The values are very comparable with literature values. For various purposes such as biomedicine and optoelectronics, the present method could be beneficial to those who wish to easily compare and determine the scattering characteristics of various plasmonic nanoparticles at a certain wavelength by using commercially-available spectroscopic techniques.

  11. 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.

  12. 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.

  13. Effects of multiple scattering on fluorescence correlation spectroscopy measurements of particles moving within optically dense media

    NASA Astrophysics Data System (ADS)

    Zustiak, Silviya; Riley, Jason; Boukari, Hacène; Gandjbakhche, Amir; Nossal, Ralph

    2012-12-01

    Fluorescence correlation spectroscopy (FCS) is increasingly being used to assess the movement of particles diffusing in complex, optically dense surroundings, in which case measurement conditions may complicate data interpretation. It is considered how a single-photon FCS measurement can be affected if the sample properties result in scattering of the incident light. FCS autocorrelation functions of Atto 488 dye molecules diffusing in solutions of polystyrene beads are measured, which acted as scatterers. Data indicated that a scattering-linked increase in the illuminated volume, as much as two fold, resulted in minimal increase in diffusivity. To analyze the illuminated beam profile, Monte-Carlo simulations were employed, which indicated a larger broadening of the beam along the axial than the radial directions, and a reduction of the incident intensity at the focal point. The broadening of the volume in the axial direction has only negligible effect on the measured diffusion time, since intensity fluctuations due to diffusion events in the radial direction are dominant in FCS measurements. Collectively, results indicate that multiple scattering does not result in FCS measurement artifacts and thus, when sufficient signal intensity is attainable, single-photon FCS can be a useful technique for measuring probe diffusivity in optically dense media.

  14. 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

  15. Capillary-scale direct measurement of hemoglobin concentration of erythrocytes using photothermal angular light scattering.

    PubMed

    Kim, Uihan; Song, Jaewoo; Lee, Donghak; Ryu, Suho; Kim, Soocheol; Hwang, Jaehyun; Joo, Chulmin

    2015-12-15

    We present a direct, rapid and chemical-free detection method for hemoglobin concentration ([Hb]), based on photothermal angular light scattering. The iron oxides contained in hemoglobin molecules exhibit high absorption of 532-nm light and generate heat under the illumination of 532-nm light, which subsequently alters the refractive index of blood. We measured this photothermal change in refractive index by employing angular light scattering spectroscopy with the goal of quantifying [Hb] in blood samples. Highly sensitive [Hb] measurement of blood samples was performed by monitoring the shifts in angularly dispersed scattering patterns from the blood-loaded microcapillary tubes. Our system measured [Hb] over the range of 0.35-17.9 g/dL with a detection limit of ~0.12 g/dL. Our sensor was characterized by excellent correlation with a reference hematology analyzer (r>0.96), and yielded a precision of 0.63 g/dL for a blood sample of 9.0 g/dL.

  16. Comparison of two Monte Carlo models of propagation of coherent polarized light in turbid scattering media

    NASA Astrophysics Data System (ADS)

    Doronin, Alexander; Radosevich, Andrew J.; Backman, Vadim; Meglinski, Igor

    2014-03-01

    Modeling the propagation of coherent polarized light through a turbid scattering medium using the Monte Carlo method enables better understanding of the peculiarities of image/signal formation in modern optical diagnostic techniques, such as optical coherence tomography (OCT), coherent/enhanced backscattering, laser speckle imaging and diffusing-wave spectroscopy (DWS). Two major ways of modeling the propagation of coherent polarized light in scattering tissue-like media are currently in use. The first approach is tracking transformations of the electric field along ray propagation. Second one is developed in analogy to the iterative procedure of the solution of Bethe-Salpeter equation. In the current paper we compare these two approaches that have been extensively used in the past for simulation of coherent polarized light propagation in scattering tissue-like media, and quantitative assessment of the enhancement of coherent backscattering of light. In particular we compare the accuracy of each technique with the results obtained in experiments and with the results of known analytical solutions. The advantages and disadvantages of each technique and their further developments are discussed.

  17. 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.

  18. 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).

  19. 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).

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    SciTech Connect

    Meyer, Matthew W.

    2013-01-01

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  6. 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.

  7. 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.

  8. Real-time detection of concealed chemical hazards under ambient light conditions using Raman spectroscopy.

    PubMed

    Cletus, Biju; Olds, William; Fredericks, Peter M; Jaatinen, Esa; Izake, Emad L

    2013-07-01

    Current concerns regarding terrorism and international crime highlight the need for new techniques for detecting unknown and hazardous substances. A novel Raman spectroscopy-based technique, spatially offset Raman spectroscopy (SORS), was recently devised for noninvasively probing the contents of diffusely scattering and opaque containers. Here, we demonstrate a modified portable SORS sensor for detecting concealed substances in-field under different background lighting conditions. Samples including explosive precursors, drugs, and an organophosphate insecticide (chemical warfare agent surrogate) were concealed inside diffusely scattering packaging including plastic, paper, and cloth. Measurements were carried out under incandescent and fluorescent light as well as under daylight to assess the suitability of the probe for different real-life conditions. In each case, it was possible to identify the substances against their reference Raman spectra in less than 1 min. The developed sensor has potential for rapid detection of concealed hazardous substances in airports, mail distribution centers, and customs checkpoints.

  9. 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

  10. Confocal Light Absorption and Scattering Spectroscopic (CLASS) imaging: From cancer detection to sub-cellular function

    NASA Astrophysics Data System (ADS)

    Qiu, Le

    Light scattering spectroscopy (LSS), an optical technique that relates the spectroscopic properties of light elastically scattered by small particles to their size, refractive index and shape, has been recently successfully employed for sensing morphological and biochemical properties of epithelial tissues and cells in vivo. LSS does not require exogenous markers, is non-invasive, and, due to its multispectral nature, can sense biological structures well beyond the diffraction limit. All that makes LSS be a very good candidate to be used both in clinical medicine for in vivo detection of disease and in cell biology to monitor cell function on the organelle scale. Recently we developed two LSS-based imaging modalities: clinical Polarized LSS (PLSS) Endoscopic Technique for locating early pre-cancerous changes in GI tract and Confocal Light Absorption and Scattering Spectroscopic (CLASS) Microscopy for studying cells in vivo without exogenous markers. One important application of the clinical PLSS endoscopic instrument, a noncontact scanning imaging device compatible with the standard clinical endoscopes and capable of detecting dysplastic changes, is to serve as a guide for biopsy in Barrett's esophagus (BE). The instrument detects parallel and perpendicular components of the polarized light, backscattered from epithelial tissues, and determines characteristics of epithelial nuclei from the residual spectra. It also can find tissue oxygenation, hemoglobin content and other properties from the diffuse light component. By rapidly scanning esophagus the PLSS endoscopic instrument makes sure the entire BE portion is scanned and examined for the presence of dysplasia. CLASS microscopy, on the other hand, combines principles of light scattering spectroscopy (LSS) with confocal microscopy. Its main purpose is to image cells on organelle scale in vivo without the use of exogenous labels which may affect the cell function. The confocal geometry selects specific region and

  11. 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.

  12. 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.

  13. Quantifying morphological alteration of RBC population from light scattering data.

    PubMed

    Mishra, Raghwendra; Sarkar, Debasish; Bhattacharya, Sourav; Mallick, Sanjaya; Chakraborty, Mousumi; Mukherjee, Debarati; Kar, Manoj; Mishra, Roshnara

    2015-01-01

    Studies of RBC morphological alterations, despite their potential clinical and experimental application, are compromised due to lack of simple and rapid techniques. As a complementary approach toward quantitative microscopy, we have reconstituted morphological information from light scattering data obtained from flow cytometer. Normal and poikilocytic agent treated samples were analyzed by microscopy and respective morphological index (MI) was calculated from the morphology based scores assigned to RBC. The samples were simultaneously analyzed by flowcytometer and the scatter data were obtained. Accordingly, the best correlated parameters of both forward scatter and side scatter were chosen to formulate a suitable regression model with MI as response. Flow cytometry data was also verified with another instrument (BD FACS Verse) and the equation obtained was validated with separate set of samples. The multivariate regression analysis yields a quadratic model with MI as response (R2 = 0.96, p <  0.001). The flow cytometric data from both instruments were in good agreement (Intra class correlation ∼0.9, p <  0.001). The model was found to simulate the sample MI with high accuracy (R2 = 0.97, p <  0.001). This proposed method was verified to be simple, rapid, quantitative and cost effective for the measurement of morphological alteration of RBC.

  14. Profiling and light scattering studies of Si surfaces

    SciTech Connect

    Church, E.L.; Takacs, P.Z.; Stover, J.C.

    1994-10-01

    There is great interest in the semiconductor industry in developing light-scattering techniques for detecting ``killer particles`` on Si wafer surfaces. The surface power spectral density (PSD) is important since it determines the intensity and angular dependence of the background scattering; understanding it will lead to a deeper understanding of finishing processes. Scattering measurements showed that Si wafer surfaces have the radiation-wavelength and angular dependences expected for weak topographic scattering. The data and independent profile measurements were used to deduce consistent values of the surface PSDs over the wavelength range 50 nm to 1 mm. The profile PSDs were found to consist of a sum of inverse power-law components, i.e., the surfaces are fractal-like. There is an analogy between the results and spontaneous thermodynamic roughening of solid surfaces: Below the critical roughening temperature, the surface topography is determined by the underlying crystal structure, while above it, the surface ``melts`` and the roughness is determined by capillary-wave excitations of the surface. Capillary waves have the well-known 1/f{sub x} profile power spectrum.

  15. Static and dynamic light scattering of healthy and malaria-parasite invaded red blood cells

    NASA Astrophysics Data System (ADS)

    Park, Yongkeun; Diez-Silva, Monica; Fu, Dan; Popescu, Gabriel; Choi, Wonshik; Barman, Ishan; Suresh, Subra; Feld, Michael S.

    2010-03-01

    We present the light scattering of individual Plasmodium falciparum-parasitized human red blood cells (Pf-RBCs), and demonstrate progressive alterations to the scattering signal arising from the development of malaria-inducing parasites. By selectively imaging the electric fields using quantitative phase microscopy and a Fourier transform light scattering technique, we calculate the light scattering maps of individual Pf-RBCs. We show that the onset and progression of pathological states of the Pf-RBCs can be clearly identified by the static scattering maps. Progressive changes to the biophysical properties of the Pf-RBC membrane are captured from dynamic light scattering.

  16. Enhanced photoluminescence of Si nanocrystals-doped cellulose nanofibers by plasmonic light scattering

    SciTech Connect

    Sugimoto, Hiroshi; Zhang, Ran; Reinhard, Björn M.; Fujii, Minoru; Perotto, Giovanni; Marelli, Benedetto; Omenetto, Fiorenzo G.; Dal Negro, Luca

    2015-07-27

    We report the development of bio-compatible cellulose nanofibers doped with light emitting silicon nanocrystals and Au nanoparticles via facile electrospinning. By performing photoluminescence (PL) spectroscopy as a function of excitation wavelength, we demonstrate plasmon-enhanced PL by a factor of 2.2 with negligible non-radiative quenching due to plasmon-enhanced scattering of excitation light from Au nanoparticles to silicon nanocrystals inside the nanofibers. These findings provide an alternative approach for the development of plasmon-enhanced active systems integrated within the compact nanofiber geometry. Furthermore, bio-compatible light-emitting nanofibers prepared by a cost-effective solution-based processing are very promising platforms for biophotonic applications such as fluorescence sensing and imaging.

  17. Enhanced photoluminescence of Si nanocrystals-doped cellulose nanofibers by plasmonic light scattering

    NASA Astrophysics Data System (ADS)

    Sugimoto, Hiroshi; Zhang, Ran; Reinhard, Björn M.; Fujii, Minoru; Perotto, Giovanni; Marelli, Benedetto; Omenetto, Fiorenzo G.; Dal Negro, Luca

    2015-07-01

    We report the development of bio-compatible cellulose nanofibers doped with light emitting silicon nanocrystals and Au nanoparticles via facile electrospinning. By performing photoluminescence (PL) spectroscopy as a function of excitation wavelength, we demonstrate plasmon-enhanced PL by a factor of 2.2 with negligible non-radiative quenching due to plasmon-enhanced scattering of excitation light from Au nanoparticles to silicon nanocrystals inside the nanofibers. These findings provide an alternative approach for the development of plasmon-enhanced active systems integrated within the compact nanofiber geometry. Furthermore, bio-compatible light-emitting nanofibers prepared by a cost-effective solution-based processing are very promising platforms for biophotonic applications such as fluorescence sensing and imaging.

  18. Stray-light suppression with high-collection efficiency in laser light-scattering experiments

    NASA Technical Reports Server (NTRS)

    Deilamian, K.; Gillaspy, J. D.; Kelleher, D. E.

    1992-01-01

    An optical system is described for collecting a large fraction of fluorescent light emitted isotropically from a cylindrical interaction region. While maintaining an overall detection efficiency of 9 percent, the system rejects, by more than 12 orders of magnitude, incident laser light along a single axis that intersects the interaction region. Such a system is useful for a wide variety of light-scattering experiments in which high-collection efficiency is desirable, but in which light from an incident laser beam must be rejected without resorting to spectral filters.

  19. The muon g-2: Dyson-Schwinger status on hadronic light-by-light scattering

    SciTech Connect

    Eichmann, Gernot; Fischer, Christian S.; Heupel, Walter; Williams, Richard

    2016-01-22

    We give a status report on the hadronic light-by-light scattering contribution to the muon’s anomalous magnetic moment from the Dyson-Schwinger approach. We discuss novel, model-independent properties of the light-by-light amplitude: we give its covariant decomposition in view of electromagnetic gauge invariance and Bose symmetry, and we identify the relevant kinematic regions that are probed under the integral. The decomposition of the amplitude at the quark level and the importance of its various diagrams are discussed and related to model approaches.

  20. Variational principle for scattering of light by dielectric particles

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.

    1978-01-01

    Consideration is given to the work of Purcell and Pennypacker (1973) where a dielectric particle is taken to be an aggregate of N polarizable elements mounted on a cubic lattice. The simultaneous equations which result from the scattering problem are presented. This theory has been discussed in the case of nonspherical and inhomogeneous objects whose dimensions are smaller than or comparable to the wavelength of incident light. A more precise numerical treatment is derived for further progress. The variational principle is invoked and the practical limit for the current version of the scheme is a dipole array on the order of 10,000 atoms. Limits to the scattering parameter due to the phase difference between neighboring atoms are discussed.

  1. Light dark matter scattering in outer neutron star crusts

    NASA Astrophysics Data System (ADS)

    Cermeño, Marina; Pérez-García, M. Ángeles; Silk, Joseph

    2016-09-01

    We calculate for the first time the phonon excitation rate in the outer crust of a neutron star due to scattering from light dark matter (LDM) particles gravitationally boosted into the star. We consider dark matter particles in the sub-GeV mass range scattering off a periodic array of nuclei through an effective scalar-vector interaction with nucleons. We find that LDM effects cause a modification of the net number of phonons in the lattice as compared to the standard thermal result. In addition, we estimate the contribution of LDM to the ion-ion thermal conductivity in the outer crust and find that it can be significantly enhanced at large densities. Our results imply that for magnetized neutron stars the LDM-enhanced global conductivity in the outer crust will tend to reduce the anisotropic heat conduction between perpendicular and parallel directions to the magnetic field.

  2. Desmin filaments studied by quasi-elastic light scattering.

    PubMed Central

    Hohenadl, M; Storz, T; Kirpal, H; Kroy, K; Merkel, R

    1999-01-01

    We studied polymers of desmin, a muscle-specific type III intermediate filament protein, using quasi-elastic light scattering. Desmin was purified from chicken gizzard. Polymerization was induced either by 2 mM MgCl(2) or 150 mM NaCl. The polymer solutions were in the semidilute regime. We concluded that the persistence length of the filaments is between 0.1 and 1 microm. In all cases, we found a hydrodynamic diameter of desmin filaments of 16-18 nm. The filament dynamics exhibits a characteristic frequency in the sense that correlation functions measured on one sample but at different scattering vectors collapse onto a single master curve when time is normalized by the experimentally determined initial decay rate. PMID:10512839

  3. Cavity-enhanced coherent light scattering from a quantum dot.

    PubMed

    Bennett, Anthony J; Lee, James P; Ellis, David J P; Meany, Thomas; Murray, Eoin; Floether, Frederik F; Griffths, Jonathan P; Farrer, Ian; Ritchie, David A; Shields, Andrew J

    2016-04-01

    The generation of coherent and indistinguishable single photons is a critical step for photonic quantum technologies in information processing and metrology. A promising system is the resonant optical excitation of solid-state emitters embedded in wavelength-scale three-dimensional cavities. However, the challenge here is to reject the unwanted excitation to a level below the quantum signal. We demonstrate this using coherent photon scattering from a quantum dot in a micropillar. The cavity is shown to enhance the fraction of light that is resonantly scattered toward unity, generating antibunched indistinguishable photons that are 16 times narrower than the time-bandwidth limit, even when the transition is near saturation. Finally, deterministic excitation is used to create two-photon N00N states with which we make superresolving phase measurements in a photonic circuit.

  4. A Light Scattering Layer for Internal Light Extraction of Organic Light-Emitting Diodes Based on Silver Nanowires.

    PubMed

    Lee, Keunsoo; Shin, Jin-Wook; Park, Jun-Hwan; Lee, Jonghee; Joo, Chul Woong; Lee, Jeong-Ik; Cho, Doo-Hee; Lim, Jong Tae; Oh, Min-Cheol; Ju, Byeong-Kwon; Moon, Jaehyun

    2016-07-13

    We propose and fabricate a random light scattering layer for light extraction in organic light-emitting diodes (OLEDs) with silver nanodots, which were obtained by melting silver nanowires. The OLED with the light scattering layer as an internal light extraction structure was enhanced by 49.1% for the integrated external quantum efficiency (EQE). When a wrinkle structure is simultaneously used for an external light extraction structure, the total enhancement of the integrated EQE was 65.3%. The EQE is maximized to 65.3% at a current level of 2.0 mA/cm(2). By applying an internal light scattering layer and wrinkle structure to an OLED, the variance in the emission spectra was negligible over a broad viewing angle. Power mode analyses with finite difference time domain (FDTD) simulations revealed that the use of a scattering layer effectively reduced the waveguiding mode while introducing non-negligible absorption. Our method offers an effective yet simple approach to achieve both efficiency enhancement and spectral stability for a wide range of OLED applications.

  5. A biophysical study of clathrin utilizing light scattering, neutron scattering and structure based computer modeling

    NASA Astrophysics Data System (ADS)

    Ferguson, Matthew Lee

    A principal component in the protein coats of certain post-golgi and endocytic vesicles is clathrin, which appears as a three-legged heteropolymer (known as a triskelion) that assembles into polyhedral baskets principally made up of pentagonal and hexagonal faces. In vitro, this assembly depends on the pH, with baskets forming more readily at low pH and less readily at high pH. We have developed procedures, based on static and dynamic light scattering, to determine the radius of gyration, Rg, and hydrodynamic radius, RH, of isolated triskelia under conditions where basket assembly occurs. Calculations based on rigid molecular bead models of a triskelion show that the measured values can be accounted for by bending of the legs and a puckering at the vertex. We also show that the values of Rg and R H measured for clathrin triskelia in solution are qualitatively consistent with the conformation of an individual triskelion that is part of a "D6 barrel" basket assembly measured by cryo-EM tomography. We extended this study by performing small angle neutron scattering (SANS) experiments on isolated triskelia in solution under conditions where baskets do not assemble. SANS experiments were consistent with previous static light scattering experiments but showed a shoulder in the scattering function at intermediate q-values just beyond the central diffraction peak (the Guinier regime). Theoretical calculations based on rigid bead models of a triskelion showed well-defined features in this region different from the experiment. A flexible bead-spring model of a triskelion and Brownian dynamics simulations were used to generate a time averaged scattering function. This model adequately described the experimental data for flexibilities close to previous estimates from the analysis of electron micrographs.

  6. Enhanced Light Scattering of Secondary Organic Aerosols by Multiphase Reactions.

    PubMed

    Li, Kun; Li, Junling; Liggio, John; Wang, Weigang; Ge, Maofa; Liu, Qifan; Guo, Yucong; Tong, Shengrui; Li, Jiangjun; Peng, Chao; Jing, Bo; Wang, Dong; Fu, Pingqing

    2017-02-07

    Secondary organic aerosol (SOA) plays a pivotal role in visibility and radiative forcing, both of which are intrinsically linked to the refractive index (RI). While previous studies have focused on the RI of SOA from traditional formation processes, the effect of multiphase reactions on the RI has not been considered. Here, we investigate the effects of multiphase processes on the RI and light-extinction of m-xylene-derived SOA, a common type of anthropogenic SOA. We find that multiphase reactions in the presence of liquid water lead to the formation of oligomers from intermediate products such as glyoxal and methylglyoxal, resulting in a large enhancement in the RI and light-scattering of this SOA. These reactions will result in increases in light-scattering efficiency and direct radiative forcing of approximately 20%-90%. These findings improve our understanding of SOA optical properties and have significant implications for evaluating the impacts of SOA on the rapid formation of regional haze, global radiative balance, and climate change.

  7. Light scattering application for bacterial cell monitoring during cultivation process

    NASA Astrophysics Data System (ADS)

    Kotsyumbas, Igor Ya.; Kushnir, Igor M.; Bilyy, Rostyslav O.; Yarynovska, Ivanna H.; Getman, Vasyl'B.; Bilyi, Alexander I.

    2007-07-01

    Monitoring of bacterial cell numbers is of great importance not only in microbiological industry but also for control of liquids contamination in the food and pharmaceutical industries. Here we describe a novel low-cost and highly efficient technology for bacterial cell monitoring during cultivation process. The technology incorporates previously developed monitoring device and algorithm of its action. The devise analyses light scattered by suspended bacterial cells. Current stage utilizes monochromatic coherent light and detects amplitudes and durations of scattered light impulses, it does not require any labeling of bacterial cell. The system is calibrated using highly purificated bacteria-free water as standard. Liquid medial are diluted and analyzed by the proposed technology to determine presence of bacteria. Detection is done for a range of particle size from 0.1 to 10 μm, and thus particles size distribution is determined. We analyzed a set of different bacterial suspensions and also their changes in quantity and size distribution during cultivation. Based on the obtained results we conclude that proposed technology can be very effective for bacteria monitoring during cultivation process, providing benefits of low simplicity and low cost of analysis with simultaneous high detection precision.

  8. Dynamic light scattering in veterinary medicine: refinement of diagnostic criteria

    NASA Astrophysics Data System (ADS)

    Dubin, Stephen; Zietz, Stanley; Gabriel, Karl L.; Gabriel, David; DellaVecchia, Michael A.; Ansari, Rafat R.

    2001-05-01

    In dynamic light scattering (DLS), the structure or material of interest, suspended in a fluid, is illuminated by a beam of laser light and the scattered light is interpreted in terms of diffusion coefficient, particle size or its distribution. DLS has shown clear promise as a non-invasive, objective and precise diagnostic modality for investigation of lens opacity (cataract) and other medical and toxicological problems. The clinical potential of LDS has been demonstrated in several species both in vivo and in vitro. In many clinical cases, discernment between normal and diseased patients is possible by simple inspection of the particle size distribution. However a more rigorous and sensitive classification scheme is needed, particularly for evaluation of therapy and estimation of tissue injury. The data supplied by DLS investigation is inherently multivariate and its most efficient interpretation requires a multivariate approach which includes the variability among specimens as well as any correlation among the variables (e.g. across the particle size distribution). We present a brief review of DLS methodology, illustrative data and our efforts toward a diagnostic classification scheme. In particular we will describe application of the Mahalanobis distance and related statistical methods to DLS data.

  9. Light-by-light scattering in the Lamb shift and the bound electron g factor

    NASA Astrophysics Data System (ADS)

    Czarnecki, Andrzej; Szafron, Robert

    2016-12-01

    We compute an O ( α2(Zα ) 6) contribution to the hydrogen-atom Lamb shift arising from light-by-light scattering. Analogous diagrams, with one atomic electric field insertion replaced by an external magnetic field, contribute to the gyromagnetic factor of the bound electron at O ( α2(Zα ) 4) . We also calculate the contribution to the gyromagnetic factor from the muon magnetic loop.

  10. Mandel'shtam-Brillouin scattering of laser light as a remote sensing tool.

    NASA Technical Reports Server (NTRS)

    Daniels, A.

    1972-01-01

    The mathematical relations regarding the intensity of scattered light are derived. The nature of density inhomogeneities in air is discussed together with scattering due to moving isothermal pressure fluctuations, the spectral distribution of scattering from static isobaric density fluctuations, and applications of Mandel'shtam-Brillouin (M-B) scattering to atmospheric sensing. It is concluded that M-B scattering of laser light from the atmosphere has an outstanding potential for remote atmospheric sensing.

  11. Changes in hemodynamics and light scattering during cortical spreading depression

    NASA Astrophysics Data System (ADS)

    Li, Pengcheng; Yang, Yuanyuan; Luo, Qingming

    2005-01-01

    Cortical spreading depression (CSD) has been known to play an important role in the mechanism of migraine, stroke and brain injure. Optical imaging of intrinsic signals has been shown a powerful method for characterizing the spatial and temporal pattern of the propagation of CSD. However, the possible physiological mechanisms underlying the intrinsic optical signal (IOS) during CSD still remain incompletely understood. In this study, a spectroscopic recording of the change in optical intrinsic signal during CSD was performed and an analysis method based on the modified Beer-Lambert law was used to estimate the changes in the concentration of HbO2 and Hb, and changes in light scattering from the spectra data. The CSD were induced by pinprick in 10 α-chloralose/urethane anesthetized Sprague-Dawley rats. In all experiments, four-phasic changes in optical reflectance were observed at 450 nm ~ 570 nm, and triphasic changes in optical reflectance were observed in the range of 570 nm ~750 nm. But at 750 nm ~ 850 nm, only biphasic changes of optical signal were detected. Converting the spectra data to the changes in light scattering and concentration of Hb and HbO2, we found that the CSD induced an initial increase in concentration of HbO2 (amplitude: 9.0+/-3.7%), which was 26.2+/-18.6 s earlier than the onset of increase of Hb concentration. Furthermore, the concentration of HbO2 showed a four-phasic change, whereas the concentration of Hb only showed a biphasic change. For the changes in light scattering during CSD, a triphasic change was observed.

  12. Ultrafast image-based dynamic light scattering for nanoparticle sizing

    NASA Astrophysics Data System (ADS)

    Zhou, Wu; Zhang, Jie; Liu, Lili; Cai, Xiaoshu

    2015-11-01

    An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing.

  13. Ultrafast image-based dynamic light scattering for nanoparticle sizing

    SciTech Connect

    Zhou, Wu; Zhang, Jie; Liu, Lili; Cai, Xiaoshu

    2015-11-15

    An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing.

  14. Light Scattering by Stochastic Solids, Aggregates and Regoliths

    NASA Astrophysics Data System (ADS)

    Lumme, K.; Rahola, J.

    1999-09-01

    We use our well-tested light scattering code based on a numerical solution of the electromagnetic integral equation to complete the full four by four Muller matrix for light scattering. Our code is very versatile as to the geometry of particles. One of our goals is doing light scattering by various particle forms to understand the two ubiquitous photopolarimetric phenomena of the atmosphereless solar system bodies, comets and interplanetary dust. These are: the universal brightening of the object towards the planetary opposition (opposition effect or spike) and the reversal of linear polarization taking place at the phase angles of about 20(o) . First, we generate stochastically deformed spheres with two different radius covariance functions in the size parameter range from 1 to 7 and apply the power law size distribution to their individual contributions. Our computations quite naturally produce both the opposition effect and the reversal of linear polarization. Second, we create with the diffusion-limited aggregation code closely packed clusters with a power law size distributed particles. Again the above mentioned two phenomena quite naturally follow. These two different particle geometries seem to indicate that an unambiguous inversion of the photopolarimetric data is not possible. This is even more so because the typical cosmic dust particles are almost certainly much bigger than allowed in our code. Finally, we model a planetary regolith by randomly placing several hundred sheres in a cylidrical geometry with a varying packing density. Once again those two phenomena follow. We also compare our computations to our Monte-Carlo code for a horizontally finite cylinder in the radiative transfer regime to see the effects fo close packing. Both the intensity and linear polarization are fairly well reproduced, excluding the forward and backward directions by the ray-optical, radiattive transfer model.

  15. Mapping Collapsing Cores in Scattered Light: HST NICMOS+WFC3 Imaging of Orion Protostars

    NASA Astrophysics Data System (ADS)

    Booker, Joseph J.; Megeath, Thomas

    2014-07-01

    A long standing question in the study of protostellar collapse is what halts the infall of a core onto a central protostar. Is the core eventually exhausted by infall, or does feedback from accretion-driven outflows disperse the core? Perhaps the best tracer of the impact of the outflow on the cores are the observed cavities carved by the outflows. We present a systematic study of near-infrared HST NICMOS+WFC3 1.6 micron images, mapping light scattered by dust grains in collapsing cores around low mass protostars with 80 AU resolution. These images are a component of HOPS, the Herschel Orion Protostar Survey, a multi-observatory survey designed to obtain 1-870 micron photometry, spectroscopy and imaging of a large sample of protostars in the Orion molecular clouds. Orion is home to half of the known protostars within 500 parsecs and is a largely unexplored ground for scattered-light studies of protostellar cores and disks. With 304 targets from the HOPS program imaged by the HST, we obtained a large sample of sources with resolved scattered light nebulae. The high spatial resolution allows us to determine properties of the protostars and collapsing cores that are not well constrained by the 1-870 micron spectral energy distributions. In particular, we map the profile of the outflow cavities for 25 sources by applying a variation of traditional edge detection techniques to the scattered light images and to radiative transfer models with known cavity geometries. From this, we estimate the fractional volumes of the collapsing cores dispersed by the outflows.

  16. 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.

  17. Multiple scattering of light in three-dimensional photonic quasicrystals.

    PubMed

    Ledermann, Alexandra; Wiersma, Diederik S; Wegener, Martin; von Freymann, Georg

    2009-02-02

    Recent experiments on three-dimensional icosahedral dielectric photonic quasicrystals have shown several unexpected features: transmitted femtosecond pulses developed a trailing "diffusive" exponential tail and the sum of (zeroth-order) transmittance and reflectance was well below unity. These experimental findings have previously been ascribed to sample imperfections. Here, we analyze these findings by using 3D periodic approximants of the ideal photonic quasicrystals. We show that the experimental observations can be explained in terms of multiple scattering of light within these structures, i.e., in terms of intrinsic rather than purely extrinsic quasicrystal properties.

  18. 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.

  19. A preview of a microgravity laser light scattering instrument

    NASA Astrophysics Data System (ADS)

    Meyer, W. V.; Ansari, R. R.

    1991-01-01

    The development of a versatile, miniature, modular light scattering instrument to be used in microgravity is described. The instrument will measure microscopic particles in the size range of thirty angstroms to above three microns. This modular instrument permits several configurations, each optimized for a particular experiment. In particular, a multiangle instrument will probably be mounted in a rack in the Space Shuttle and on the Space Station. It is possible that a Space Shuttle glove-box and a lap-top computer containing a correlator card can be used to perform a number of experiments and to demonstrate the technology needed for more elaborate investigations.

  20. HD100546 multi-epoch scattered light observations

    SciTech Connect

    Avenhaus, Henning; Quanz, Sascha P.; Meyer, Michael R.; Brittain, Sean D.; Carr, John S.; Najita, Joan R.

    2014-07-20

    We present H, K{sub s}, and L' filter polarimetric differential imaging (PDI) data for the transitional disk around HD100546 obtained in 2013, together with an improved re-reduction of previously published 2006 data. We reveal the disk in polarized scattered light in all three filters, achieving an inner working angle of ∼0.''1. Additional, short-exposure observations in the H and K{sub s} filters probe the surroundings of the star down to ∼0.''03 (∼3 AU). HD100546 is fascinating because of its variety of sub-structures possibly related to forming planets in the disk, and PDI is currently the best technique for imaging them in the near-IR. For the first time ever, we detect a disk in L-band PDI data, and we constrain the outer radius of the inner hole to 14 ± 2 AU and its eccentricity to <0.133. A dark lane is detected between ∼0.''2-0.''6 AU in the front side of the disk, which is likely an effect of the scattering angle and the scattering function of the grains. We find a spiral arm in the northeast that has no obvious connection to spiral arms seen before by other authors further out in the disk, but winds are in the same direction (clockwise). The two bright scattering peaks along the semi-major axis are asymmetric, with the southeastern one being significantly brighter. This could be related to the inner companion candidate that is close to the brighter side of the disk at the time of the observations. The scattering color is close to gray between the H and K{sub s} filters ([H]–[K{sub s}] = 0.19 ± 0.11), but the scattering in the L' filter is significantly weaker ([H]–[L'] = –1.08 ± 0.35, [K{sub s}]–[L'] = –1.27 ± 0.35). We measure the position angle of the disk to be 138° ± 3°, consistent with previous observations, and we derive the dust scattering function in the H and K{sub s} filters between ∼35° and ∼130° at two different radii (30-50 and 80-110 AU) and show that our results are consistent with a disk that is more strongly

  1. 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.

  2. Light-scattering study of petroleum asphaltene aggregation.

    PubMed

    Burya, Y G; Yudin, I K; Dechabo, V A; Kosov, V I; Anisimov, M A

    2001-08-20

    Dynamic light scattering with an original optical scheme has been used for the investigation of opaque (strongly light-absorbing) asphaltene colloids in crude oils and hydrocarbon mixtures. Diffusion-limited aggregation and reaction-limited aggregation as well as a crossover between these two regimes have been observed. A simple interpolation for the crossover kinetics is proposed. Asphaltene colloidal structures, originally persisting in crude oils, have been detected. Addition of a precipitant above a threshold induces asphaltene aggregation. Depending on the nature of the precipitant, different crude oils respond differently on its addition: (a) exponential-in-time growth of aggregates to huge flocks or (b) fast formation of stable-in-size particles.

  3. First Results from the Light and Spectroscopy Concept Inventory

    ERIC Educational Resources Information Center

    Bardar, Erin M.

    2008-01-01

    This article presents results from a two-semester field test of the Light and Spectroscopy Concept Inventory (LSCI). Statistical analysis indicates that the LSCI has the sensitivity to measure statistically significant changes in students' understanding of light-related topics due to instruction in introductory astronomy courses and to distinguish…

  4. Light-scattering Characteristics of Metal Nanoparticles on a Single Bacterial Cell.

    PubMed

    Kinoshita, Takamasa; Kiso, Keita; LE, Dung Q; Shiigi, Hiroshi; Nagaoka, Tsutomu

    2016-01-01

    Metal nanoparticles express unique light-scattering characteristics based on the localized surface plasmon resonance, which depends on the metal species, particle size, and aggregation state of the nanoparticles. Therefore, we focused on the light-scattering characteristics of metal nanoparticles, such as silver, gold, and copper oxide, adsorbed on a bacterium. Monodisperse silver nanoparticles expressed the strongest scattered light among them, and showed various colors of scattered light. Although a monodisperse gold nanoparticle produced monochromatic light (green color), the color of the scattered light strongly depended on the aggregation state of the nanoparticles on a bacterium. On the other hand, copper oxide nanoparticles expressed monochromatic light (blue color), regardless of their aggregation states on a bacterium. We examined details concerning the light-scattering characteristics of metal nanoparticles, and discussed the possibility of their applications to bacterial cell imaging.

  5. Study of Scattered Light from Known Debris Disks

    NASA Technical Reports Server (NTRS)

    Rodriguez, Joseph E.; Weinberger, Alycia J.; Roberge, Aki

    2011-01-01

    Using the Spitzer Space Telescope, a group of edge on debris disks, surrounding main-sequence shell stars have been discovered in the infrared. These disks are of high interest because they not only have dust, but an observed amount of circumstellar gas. HD158352 was an ideal target to try and image the disk because it was one of the closest stars in this group. Using the Hubble Space Telescope's Space Telescope Imaging Spectrograph (STIS), we attempted to take a direct image of the light scattered from the known disk in a broad optical bandpass. Studying these particular type of disks in high detail will allow us to learn more about gas-dust interactions. In particular, this will allow us to learn how the circumstellar gas evolves during the planet-forming phase. Even though it was predicted that the disk should have a magnitude of 20.5 at 3", no disk was seen in any of the optical images. This suggests that the parameters used to predict the brightness of the disk are not what we first anticipated and adjustments to the model must be performed. We also present the blue visible light spectrum of the scattered light from the debris disk surrounding Beta Pictoris. We are analyzing archival observations taken by Heap, using Hubble Space Telescope's STIS instrument. A long slit with a bar was used to occult Beta Pictoris as well as the PSF star. This was done because it is necessary to subtract a PSF observed the same way at the target to detect the disk. It appears that we have detected light from the disk but the work was in progress at the time of the abstract deadline.

  6. Quantifying the Solubility of Boron Nitride Nanotubes and Sheets with Static Light Scattering and Refractometry

    SciTech Connect

    Mutz, M; Eastwood, Eric Allen; Dadmun, Mark D

    2013-01-01

    The dissolution of nanoparticles, particularly those containing boron, is an important area of interest for polymer nanocomposite formation and material development. In this work, the solubility of boron nitride nanotubes (BNNT), functionalized boron nitride nanotubes (FBNNT), and boron nitride sheets (BNZG) is quantified in toluene and THF with static light scattering, refractometry, UV vis spectroscopy, and physical observations. UV vis spectroscopy provides a method to determine the concentration and solubility limits of the solutions tested. Using light scattering, the second virial coefficient, A2, is determined and used to calculate , the solute solvent interaction parameter. The Hildebrand solubility parameter, , is then extracted from this data using the Hildebrand Scatchard Solution Theory. A list of potential good solvents based on the estimated value is provided for each nanoparticle. Single-walled carbon nanotubes (SWNTs) and prepolymers (EN4 and EN8) used to synthesize polyurethanes were also tested, because the published and molar attraction constants of these materials provided a selfconsistent check. The dn/dc of SWNTs and boron-containing particles was measured for the first time in this work. A solvent screen for BN-ZG provides additional information that supports the obtained and . Three systems were found to have values below 0.5 and were thermodynamically soluble: BNNT in THF, EN8 in THF, and EN8 in toluene.

  7. Stray Light Correction in the Optical Spectroscopy of Crystals

    PubMed Central

    Hendler, Richard W.; Meuse, Curtis W.; Gallagher, Travis; Labahn, Joerg; Kubicek, Jan; Smith, Paul D.; Kakareka, John W.

    2015-01-01

    It has long been known in spectroscopy that light not passing through a sample, but reaching the detector (i.e., stray light), results in a distortion of the spectrum known as absorption flattening. In spectroscopy with crystals, one must either include such stray light or take steps to exclude it. In the former case, the derived spectra are not accurate. In the latter case, a significant amount of the crystal must be masked off and excluded. In this paper, we describe a method that allows use of the entire crystal by correcting the distorted spectrum. PMID:26688880

  8. Total internal reflection and dynamic light scattering microscopy of gels

    NASA Astrophysics Data System (ADS)

    Gregor, Brian F.

    Two different techniques which apply optical microscopy in novel ways to the study of biological systems and materials were built and applied to several samples. The first is a system for adapting the well-known technique of dynamic light scattering (DLS) to an optical microscope. This can detect and scatter light from very small volumes, as compared to standard DLS which studies light scattering from volumes 1000x larger. The small scattering volume also allows for the observation of nonergodic dynamics in appropriate samples. Porcine gastric mucin (PGM) forms a gel at low pH which lines the epithelial cell layer and acts as a protective barrier against the acidic stomach environment. The dynamics and microscopic viscosity of PGM at different pH levels is studied using polystyrene microspheres as tracer particles. The microscopic viscosity and microrheological properties of the commercial basement membrane Matrigel are also studied with this instrument. Matrigel is frequently used to culture cells and its properties remain poorly determined. Well-characterized and purely synthetic Matrigel substitutes will need to have the correct rheological and morphological characteristics. The second instrument designed and built is a microscope which uses an interferometry technique to achieve an improvement in resolution 2.5x better in one dimension than the Abbe diffraction limit. The technique is based upon the interference of the evanescent field generated on the surface of a prism by a laser in a total internal reflection geometry. The enhanced resolution is demonstrated with fluorescent samples. Additionally. Raman imaging microscopy is demonstrated using the evanescent field in resonant and non-resonant samples, although attempts at applying the enhanced resolution technique to the Raman images were ultimately unsuccessful. Applications of this instrument include high resolution imaging of cell membranes and macroscopic structures in gels and proteins. Finally, a third

  9. Probing a Spray Using Frequency-Analyzed Light Scattering

    NASA Technical Reports Server (NTRS)

    Eskridge, Richard; Lee, Michael H.; Rhys, Noah O.

    2008-01-01

    Frequency-analyzed laser-light scattering (FALLS) is a relatively simple technique that can be used to measure principal characteristics of a sheet of sprayed liquid as it breaks up into ligaments and then the ligaments break up into droplets. In particular, through frequency analysis of laser light scattered from a spray, it is possible to determine whether the laser-illuminated portion of the spray is in the intact-sheet region, the ligament region, or the droplet region. By logical extension, it is possible to determine the intact length from the location of the laser beam at the transition between the intact-sheet and ligament regions and to determine a breakup frequency from the results of the frequency analysis. Hence, FALLS could likely be useful both as a means of performing research on sprays in general and as a means of diagnostic sensing in diverse applications in which liquid fuels are sprayed. Sprays are also used for drying and to deposit paints and other coating materials.

  10. Online submicron particle sizing by dynamic light scattering using autodilution

    NASA Technical Reports Server (NTRS)

    Nicoli, David F.; Elings, V. B.

    1989-01-01

    Efficient production of a wide range of commercial products based on submicron colloidal dispersions would benefit from instrumentation for online particle sizing, permitting real time monitoring and control of the particle size distribution. Recent advances in the technology of dynamic light scattering (DLS), especially improvements in algorithms for inversion of the intensity autocorrelation function, have made it ideally suited to the measurement of simple particle size distributions in the difficult submicron region. Crucial to the success of an online DSL based instrument is a simple mechanism for automatically sampling and diluting the starting concentrated sample suspension, yielding a final concentration which is optimal for the light scattering measurement. A proprietary method and apparatus was developed for performing this function, designed to be used with a DLS based particle sizing instrument. A PC/AT computer is used as a smart controller for the valves in the sampler diluter, as well as an input-output communicator, video display and data storage device. Quantitative results are presented for a latex suspension and an oil-in-water emulsion.

  11. Particle sizing by weighted measurements of scattered light

    NASA Technical Reports Server (NTRS)

    Buchele, Donald R.

    1988-01-01

    A description is given of a measurement method, applicable to a poly-dispersion of particles, in which the intensity of scattered light at any angle is weighted by a factor proportional to that angle. Determination is then made of four angles at which the weighted intensity is four fractions of the maximum intensity. These yield four characteristic diameters, i.e., the diameters of the volume/area mean (D sub 32 the Sauter mean) and the volume/diameter mean (D sub 31); the diameters at cumulative volume fractions of 0.5 (D sub v0.5 the volume median) and 0.75 (D sub v0.75). They also yield the volume dispersion of diameters. Mie scattering computations show that an average diameter less than three micrometers cannot be accurately measured. The results are relatively insensitive to extraneous background light and to the nature of the diameter distribution. Also described is an experimental method of verifying the conclusions by using two microscopic slides coated with polystyrene microspheres to simulate the particles and the background.

  12. Scattering of circularly polarized light by a rotating black hole

    NASA Astrophysics Data System (ADS)

    Frolov, Valeri P.; Shoom, Andrey A.

    2012-07-01

    We study scattering of polarized light by a rotating (Kerr) black hole of mass M and angular momentum J. In order to keep trace of the polarization dependence of photon trajectories one can use the following dimensionless parameter: ɛ=±(ωM)-1, where ω is the photon frequency and the sign + (-) corresponds to the right (left) circular polarization. We assume that |ɛ|≪1 and use the modified geometric optics approximation developed in [Phys. Rev. D 84, 044026 (2011)]; that is, we include the first order in ɛ polarization-dependent terms into the eikonal equation. These corrections modify late-time behavior of photons. We demonstrate that the photon moves along a null curve, which in the limit ɛ=0 becomes a null geodesic. We focus on the scattering problem for polarized light. Namely, we consider the following problems: (i) How does the photon’s bending angle depend on its polarization? (ii) How does the position of the image of a pointlike source depend on its polarization? (iii) How does the arrival time of photons depend on their polarization? We perform the numerical calculations that illustrate these effects for an extremely rotating black hole and discuss their possible applications.

  13. DUST EVOLUTION CAN PRODUCE SCATTERED LIGHT GAPS IN PROTOPLANETARY DISKS

    SciTech Connect

    Birnstiel, Tilman; Andrews, Sean M.; Pinilla, Paola; Kama, Mihkel E-mail: sandrews@cfa.harvard.edu E-mail: mkama@strw.leidenuniv.nl

    2015-11-01

    Recent imaging of protoplanetary disks with high resolution and contrast have revealed a striking variety of substructure. Of particular interest are cases where near-infrared scattered light images show evidence for low-intensity annular “gaps.” The origins of such structures are still uncertain, but the interaction of the gas disk with planets is a common interpretation. We study the impact that the evolution of the solid material can have on the observable properties of disks in a simple scenario without any gravitational or hydrodynamical disturbances to the gas disk structure. Even with a smooth and continuous gas density profile, we find that the scattered light emission produced by small dust grains can exhibit ring-like depressions similar to those presented in recent observations. The physical mechanisms responsible for these features rely on the inefficient fragmentation of dust particles. The occurrence and position of the proposed “gap” features depend most strongly on the dust-to-gas ratio, the fragmentation threshold velocity, the strength of the turbulence, and the age of the disk, and should be generic (at some radius) for typically adopted disk parameters. The same physical processes can affect the thermal emission at optically thin wavelengths (∼1 mm), although the behavior can be more complex; unlike for disk–planet interactions, a “gap” should not be present at these longer wavelengths.

  14. Theoretical and experimental comparison of tissue phantoms using white light spectroscopy

    NASA Astrophysics Data System (ADS)

    Popov, Kaloyan A.; Kurzweg, Timothy P.

    2011-03-01

    White light spectroscopy has the potential to be used as an optical biopsy method, as backscattered light data can be related to the cellular nucleus size. In this paper, we compare experimental backscattering results against the general Mie theory simulations. Our experimental technique obtains results in terms of intensity vs. wavelength. We also use optical filters, to limit the source spectrum, and when converting the backscattered data into the Fourier domain, we obtain characteristic frequencies which describe the scatterer size. Phantom tissues, comprised of polystyrene spheres in a liquid or gel, are used for the experiments.

  15. Studies on Light Scattering and Absorption Properties of Ice Clouds for Visible and Infrared Laser Wavelengths.

    DTIC Science & Technology

    1983-08-08

    view on the multiple backscattered return, depolarization and polarization characteristics. Three papers are associated with the study of light ...scattering phase function, degree of linear polarization and depolarization ratio for randomly oriented columns and plates with experi- mental scattering...fundamental contribution to the field of light scattering by nonspherical particles . Using the computational technique developed in this paper, we further

  16. A versatile, low-cost approach to dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Pristinski, Denis; Chastek, Thomas Q.

    2009-04-01

    We describe a method for constructing a fiber-optic-based dynamic light scattering (DLS) instrument from commonly available components, without a need for custom-made parts. Details are provided that allow for academic researchers from diverse backgrounds to build this DLS instrument with minimal effort and at a low cost. This approach, while providing good sensitivity and high accuracy (e.g., measuring the size of latex standards to within 1% relative standard deviation), possesses several advantages not found, in their entirety, in existing DLS instrumentation. It was observed that, even though an arbitrary scattering angle could be selected, aligning this instrument to obtain optimal detection efficiency can be completed in as little as a few minutes. Also, complications associated with light refraction at the sample cell interface are avoided. Small volumes (<10 µL) can be measured, for example, by hanging a solution droplet from the fiber optic probe tips. In addition, use of fiber optic probes allows the beam path length to be as short as 1.6 mm while measuring at 90°, which reduces the likelihood of multiple scattering. With minimal customization, compact submersible probes and a portable battery-operated DLS instrument were made as examples of potential implementation. Finally, this approach is versatile, and can be incorporated into a wide variety of reactors, for in situ characterization, and other instrumentation for hybrid measurements. This type of in situ measurement was conducted after mounting the DLS probes inside a standard three-neck flask. This allowed for direct monitoring of the growth of silica nanoparticles prepared via Stöber synthesis.

  17. Modeling diffuse reflectance measurements of light scattered by layered tissues

    NASA Astrophysics Data System (ADS)

    Rohde, Shelley B.

    In this dissertation, we first present a model for the diffuse reflectance due to a continuous beam incident normally on a half space composed of a uniform scattering and absorbing medium. This model is the result of an asymptotic analysis of the radiative transport equation for strong scattering, weak absorption and a defined beam width. Through comparison with the diffuse reflectance computed using the numerical solution of the radiative transport equation, we show that this diffuse reflectance model gives results that are accurate for small source-detector separation distances. We then present an explicit model for the diffuse reflectance due to a collimated beam of light incident normally on layered tissues. This model is derived using the corrected diffusion approximation applied to a layered medium, and it takes the form of a convolution with an explicit kernel and the incident beam profile. This model corrects the standard diffusion approximation over all source-detector separation distances provided the beam is sufficiently wide compared to the scattering mean-free path. We validate this model through comparison with Monte Carlo simulations. Then we use this model to estimate the optical properties of an epithelial layer from Monte Carlo simulation data. Using measurements at small source-detector separations and this model, we are able to estimate the absorption coefficient, scattering coefficient and anisotropy factor of epithelial tissues efficiently with reasonable accuracy. Finally, we present an extension of the corrected diffusion approximation for an obliquely incident beam. This model is formed through a Fourier Series representation in the azimuthal angle which allows us to exhibit the break in axisymmetry when combined with the previous analysis. We validate this model with Monte Carlo simulations. This model can also be written in the form of a convolution of an explicit kernel with the incident beam profile. Additionally, it can be used to

  18. Detection of Changes on and below the Surface in Epithelium Mucosal Tissue Structure using Scattered Light

    NASA Astrophysics Data System (ADS)

    Taslidere, Ezgi

    The aim of this work is to answer the question of whether it is possible to detect changes on and below the surface in epithelium tissue structure using light reflected from the tissue over an area (2-D scan) illuminated by an optical sensor (fiber) emitting light at either one wavelength or with white light. Towards that end we model the 2-D reflected scans using a Stochastic Decomposition Method (SDM). The emphasis in this work is on the novelty of the proposed model and its theoretical pinning and foundation. The model is biologically motivated by the stochastic textural nature of the tissue. We model the textural content (which relates to tissue morphology) that manifests itself in the 2-D scans. Unlike previous works that analyze the scattered signal at one spot at various wavelengths, our method statistically analyzes 2-D scans of light scattering data over an area, and extracts from the data features (SDM parameters) that change with changes in the tissue morphology. The examination of an area rather than a spot not only leads to a more reliable calculation of the extracted parameters using single techniques (e.g. nuclear size distribution), but it also leads to the computation of additional information embedded in the spatial texture that our decomposition technique arrives at by modeling the hidden correlations that are obtained only by interrogating a wide sample area. To the best of our knowledge, this is the first attempt at modeling the scattered light over an area using a stochastic decomposition model that allows for the assessment of correlation and textural characteristics that otherwise could not be revealed when the analysis of the scattering signal is a function of wavelength or angle. We also come up with a segmentation technique to raise a flag on the fly when a transition occurs between different mucosal architectures on the surface. The segmentation is based on a novel difference metric for detecting an abrupt change in the parameters

  19. 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.

  20. 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.

  1. Visible Light Spectroscopy of GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Lederer, Susan M.; Cowardin, Heather; Barker, Edwin S.; Abercromby, Kira J.

    2012-01-01

    Our goal is to understand the physical characteristics of debris at geosynchronous orbit (GEO). Our approach is to compare the observed reflectance as a function of wavelength with laboratory measurements of typical spacecraft surfaces to understand what the materials are likely to be. Because debris could be irregular in shape and tumbling at an unknown rate, rapid simultaneous measurements over a range of wavelengths are required. Acquiring spectra of optically faint objects with short exposure times to minimize these effects requires a large telescope. We describe optical spectroscopy obtained during 12-14 March 2012 with the IMACS imaging spectrograph on the 6.5-m 'Walter Baade' Magellan telescope at Las Campanas Observatory in Chile. When used in f/2 imaging mode for acquisition, this instrument has a field of view of 30 arc-minutes in diameter. After acquisition and centering of a GEO object, a 2.5 arc-second wide slit and a grism are moved into the beam for spectroscopy. We used a 200 l/mm grism blazed at 660 nm for wavelength coverage in the 500-900 nm region. Typical exposure times for spectra were 15-30 seconds. Spectra were obtained for five objects in the GEO regime listed as debris in the US Space Command public catalog, and one high area to mass ratio GEO object. In addition spectra were obtained of three cataloged IDCSP (Initial Defense Communications Satellite Program) satellites with known initial properties just below the GEO regime. All spectra were calibrated using white dwarf flux standards and solar analog stars. We will describe our experiences using Magellan, a telescope never used previously for orbital debris spectroscopy, and our initial results.

  2. Visible Light Spectroscopy of GEO Debris

    NASA Astrophysics Data System (ADS)

    Seitzer, P.; Abercromby, K. J.; Barker, E. S.; Cardona, T.; Lederer, S. M.; Cowardin, H.

    2012-09-01

    Our goal is to understand the physical characteristics of debris at geosynchronous orbit (GEO). Our approach is to compare the observed reflectance as a function of wavelength with laboratory measurements of typical spacecraft surfaces to understand what the materials are likely to be. Because debris could be irregular in shape and tumbling at an unknown rate, rapid simultaneous measurements over a range of wavelengths are required. Acquiring spectra of optically faint objects with short exposure times to minimize these effects requires a large telescope. We describe optical spectroscopy obtained with two imaging spectrographs on the 6.5-m Magellan telescopes at Las Campanas Observatory in Chile. Our first observing run was 12-14 March 2012 with the IMACS imaging spectrograph on the 'Walter Baade' telescope, which was followed by a run on 1-2 May 2012 on the 'Landon Clay' telescope. Both telescopes have spectrographs with an imaging mode for acquisition. After acquisition and centering of a GEO object, a slit and grism are moved into the beam for spectroscopy. We used low resolution grisms blazed near 600 nm for wavelength coverage in the 400-800 nm region. Typical exposure times for spectra were 15-30 seconds. Spectra were obtained for objects in the GEO regime listed as debris in the US Space Command public catalog, and one high area to mass ratio GEO object. In addition spectra were obtained of IDCSP (Initial Defense Communications Satellite Program) satellites with known initial properties just below the GEO regime. All spectra were calibrated using white dwarf flux standards and solar analog stars. We will describe our experiences using Magellan, a telescope never used previously for orbital debris spectroscopy, and our initial results. 1. This work is supported by NASAs Orbital Debris Program Office, Johnson Space Center, Houston, Texas, USA. 2. This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

  3. Light scattering in dense and cold 87Rb

    NASA Astrophysics Data System (ADS)

    Haga, Kasie; Roof, S. J.; Balik, S.; Havey, M. D.; Sokolov, Igor; Kupriyanov, Dimitriy

    2013-05-01

    Quantum optics in ultracold and high-density, but non quantum degenerate, atomic gases is a promising area of research. Studies of quantum hologram creation in optically dressed samples, enhanced molecule formation, and ultracold plasma physics in the strongly coupled regime are intriguing areas of current activity. Exploration of the role of spatial disorder on light propagation in such systems and disorder-mediated formation and manipulation of subradiant and superradiant configurations are topics of considerable interest. In this paper we present experimental results on light scattering in a cold and quite high density gas of 87Rb atoms. The sample is prepared in an optical dipole trap, and has a peak density ~ 6 . 1013 atoms/cm3 and a temperature ~ 60 μK . Here the F = 2 -->F' = 3 nearly closed hyperfine transition is studied. We discuss two experimental geometries. In one, near-resonance radiation is directed towards the sample; the response is recorded as a function of time and frequency. In a second, the probe beam is overlapped with a far off resonance light shift laser, which reduces the optical depth through the central region of the sample, allowing for generation of a quasi one dimensional configuration. Supported by NSF.

  4. Two-dimensional electronic spectroscopy using incoherent light: theoretical analysis.

    PubMed

    Turner, Daniel B; Howey, Dylan J; Sutor, Erika J; Hendrickson, Rebecca A; Gealy, M W; Ulness, Darin J

    2013-07-25

    Electronic energy transfer in photosynthesis occurs over a range of time scales and under a variety of intermolecular coupling conditions. Recent work has shown that electronic coupling between chromophores can lead to coherent oscillations in two-dimensional electronic spectroscopy measurements of pigment-protein complexes measured with femtosecond laser pulses. A persistent issue in the field is to reconcile the results of measurements performed using femtosecond laser pulses with physiological illumination conditions. Noisy-light spectroscopy can begin to address this question. In this work we present the theoretical analysis of incoherent two-dimensional electronic spectroscopy, I((4)) 2D ES. Simulations reveal diagonal peaks, cross peaks, and coherent oscillations similar to those observed in femtosecond two-dimensional electronic spectroscopy experiments. The results also expose fundamental differences between the femtosecond-pulse and noisy-light techniques; the differences lead to new challenges and new opportunities.

  5. Quantification of optical Doppler broadening and optical path lengths of multiply scattered light by phase modulated low coherence interferometry

    NASA Astrophysics Data System (ADS)

    Varghese, B.; Rajan, V.; van Leeuwen, T. G.; Steenbergen, W.

    2007-07-01

    We show experimental validation of a novel technique to measure optical path length distributions and path length resolved Doppler broadening in turbid media for different reduced scattering coefficients and anisotropies. The technique involves a phase modulated low coherence Mach-Zehnder interferometer, with separate fibers for illumination and detection. Water suspensions of Polystyrene microspheres with high scattering and low absorption levels are used as calibrated scattering phantoms. The path length dependent diffusion broadening or Doppler broadening of scattered light is shown to agree with Diffusive Wave Spectroscopy within 5%. The optical path lengths are determined experimentally from the zero order moment of the phase modulation peak around the modulation frequency in the power spectrum and the results are validated with Monte Carlo simulations.

  6. Quantification of optical Doppler broadening and optical path lengths of multiply scattered light by phase modulated low coherence interferometry.

    PubMed

    Varghese, B; Rajan, V; van Leeuwen, T G; Steenbergen, W

    2007-07-23

    We show experimental validation of a novel technique to measure optical path length distributions and path length resolved Doppler broadening in turbid media for different reduced scattering coefficients and anisotropies. The technique involves a phase modulated low coherence Mach-Zehnder interferometer, with separate fibers for illumination and detection. Water suspensions of Polystyrene microspheres with high scattering and low absorption levels are used as calibrated scattering phantoms. The path length dependent diffusion broadening or Doppler broadening of scattered light is shown to agree with Diffusive Wave Spectroscopy within 5%. The optical path lengths are determined experimentally from the zero order moment of the phase modulation peak around the modulation frequency in the power spectrum and the results are validated with Monte Carlo simulations.

  7. Phase separation of polymer mixtures induced by light and heat: a comparative study by light scattering

    NASA Astrophysics Data System (ADS)

    Ochi, Yuki; Kawakubo, Rie; Van-Pham, Dan-Thuy; Kitamura, Yuki; Nakanishi, Hideyuki; Norisuye, Tomohisa; Tran-Cong-Miyata, Qui

    2015-12-01

    Phase separation of binary blends composed of a polystyrene derivative (PS) and poly (vinyl methyl ether) (PVME) with a lower critical solution temperature (LCST) was experimentally induced by two different methods: heating and UV light irradiation. Using laser light scattering combined with the temperature jump (T-jump) technique, it was demonstrated that in the case of heating, the mixture undergoes phase separation via the nucleation-and-growth (NG) and the spinodal decomposition (SN) processes under shallow and deep quenches, respectively. Particularly, the crossover from the spinodal decomposition to the nucleation-and-growth process was observed at long time under a deep T-jump by light-scattering experiments. On the other hand, in the photo-crosslink case, the PS/PVME blends undergo a nucleation-and-growth process upon irradiation with weak light intensity, whereas the mixture exhibits the spinodal decomposition under irradiation with strong light intensity. From the analysis of the light-scattering data obtained for the blends under the photo-crosslink, the kinetic data reveal the suppression of morphologies having large characteristic length scales. This feature clearly differs from the phase separation induced by heating where no mode-suppression process was observed. It was also found that distribution of the characteristic length scales (the regularity) of the morphology becomes narrow as the phase separation proceeds for reacting blends, whereas it becomes broader as the phase separation proceeds by heating, revealing the important roles of reaction in the suppression of fluctuations with long wavelengths. These experimental results establish a method to control the length scales and the regularity of the morphology of polymer blends by chemical reaction.

  8. Development of a versatile laser light scattering instrument

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Ansari, Rafat R.

    1990-01-01

    A versatile laser light scattering (LLS) instrument is developed for use in microgravity to measure microscopic particles of 30 A to above 3 microns. Since it is an optical technique, LLS does not affect the sample being studied. A LLS instrument built from modules allows several configurations, each optimized for a particular experiment. The multiangle LLS instrument can be mounted in the rack in the Space Shuttle and on Space Station Freedom. It is possible that a Space Shuttle glove-box and a lap-top computer containing a correlator card can be used to perform a number of experiments and to demonstrate the technology needed for more elaborate investigations. This offers simple means of flying a great number of experiments without the additional requirements of full-scale flight hardware experiments.

  9. Integrated fiber optic probe for dynamic light scattering

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans S.; Khan, Romel R.; Suh, Kwang

    1993-01-01

    An integrated fiber optic probe, comprising a monomode optical fiber fusion spliced to a short length of a graded-index multimode fiber, is fabricated for use as a coherent receiver in dynamic light scattering. The multimode fiber is cleaved to provide a gradient-index fiber lens with a focal length of 125 microns and an f-number close to unity. An integrated fiber receiver is used to measure the intensity-intensity autocorrelation data from a 0.05 percent by weight concentration of an aqueous suspension of polystyrene latex spheres. Analysis of 100 independent data sets indicates that the particle size can be recovered with an accuracy of +/- 1 percent.

  10. Physicochemical and Light Scattering Studies on Ribosome Particles

    PubMed Central

    Scafati, Anna Reale; Stornaiuolo, Maria Rosaria; Novaro, Patrizia

    1971-01-01

    The light scattering technique has been used to measure the molecular weight of Escherichia coli ribosomes. The 30S, 50S, and 70S components have been isolated and purified. The refractive index increment dn/dc was found to have the same value, (0.20 ±0.01) cm3/g, for the three species. The molecular weights are (1.0 ±0.1)·106, (1.7 ±0.1)·106, and (2.9 ±0.3)·106 daltons respectively. Some information about the dimensions in solution (radius of gyration) and the interaction constant (second virial coefficient) have been obtained, and their significance is discussed. PMID:4931397

  11. Preliminary Remediation of Scattered Light in NEAR MSI Images

    NASA Astrophysics Data System (ADS)

    Li, Han; Robinson, Mark S.; Murchie, Scott

    2002-01-01

    During a failed Eros orbit insertion maneuver on 20 December 1998, more than 28 kg of hydrazine were expended by attitude control jets on the NEAR Shoemaker spacecraft. Deposition of burn products on the outer optic of the multispectral imager, or MSI, resulted in a wavelength-dependent degradation of the system point-spread function (PSF). The scattered light is progressively worse in the shortest and longest wavelength filters, especially at 450 and 1050 nm. The degraded PSF was characterized using numerous images of Canopus acquired subsequent to the anomaly. There is no evidence for temporal change in the PSF since the burn abort incident. A fast Fourier transform-based image restoration method using the optimal filter recovers most of the spatial resolution of the original images while preserving radiometric accuracy for the 550- to 1000-nm images. This procedure has enabled nearly unimpeded monochrome imaging of asteroid morphology and select 5-color measurements at a scale of ∼5 pixels.

  12. Brillouin light scattering studies of 2D magnonic crystals.

    PubMed

    Tacchi, S; Gubbiotti, G; Madami, M; Carlotti, G

    2017-02-22

    Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.

  13. Preface: Electromagnetic and Light Scattering by Nonspherical Particles XIV

    NASA Technical Reports Server (NTRS)

    Dubovik, Oleg; Labonnete, Laurent; Litvinov, Pavel; Parol, Frederic; Mischenko, Michael

    2014-01-01

    The 14th Electromagnetic and Light Scattering Conference (ELS-XIV) was held at the Universit de Lille 1, Villeneuve d'Ascq, France on 17-21 June 2013. The conference was attended by 200 scientists from 26 countries. The scientific program included one plenary lecture, 12 invited reviews, 100 contributed oral talks, and 86 poster presentations. The program, the abstracts, and the slides of the oral presentations are available at the conference web site http:www-loa.univ-lille1.frELS-XIV. To highlight one of the traditional ELS themes, the ELS-XIV featured a special session on Remote sensing of aerosols and clouds using polarimetric observations. This session was sponsored and co-organized by the French space agency CNES and attracted representatives from nearly all research teams word-wide involved in the development and active use of space-borne, in situ, and ground-based polarimetric observations.

  14. Brillouin light scattering studies of 2D magnonic crystals

    NASA Astrophysics Data System (ADS)

    Tacchi, S.; Gubbiotti, G.; Madami, M.; Carlotti, G.

    2017-02-01

    Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.

  15. Characterization of magnetic nanoparticle by dynamic light scattering

    PubMed Central

    2013-01-01

    Here we provide a complete review on the use of dynamic light scattering (DLS) to study the size distribution and colloidal stability of magnetic nanoparticles (MNPs). The mathematical analysis involved in obtaining size information from the correlation function and the calculation of Z-average are introduced. Contributions from various variables, such as surface coating, size differences, and concentration of particles, are elaborated within the context of measurement data. Comparison with other sizing techniques, such as transmission electron microscopy and dark-field microscopy, revealed both the advantages and disadvantages of DLS in measuring the size of magnetic nanoparticles. The self-assembly process of MNP with anisotropic structure can also be monitored effectively by DLS. PMID:24011350

  16. Light scattering by lunar-like particle size distributions

    NASA Technical Reports Server (NTRS)

    Goguen, Jay D.

    1991-01-01

    A fundamental input to models of light scattering from planetary regoliths is the mean phase function of the regolith particles. Using the known size distribution for typical lunar soils, the mean phase function and mean linear polarization for a regolith volume element of spherical particles of any composition were calculated from Mie theory. The two contour plots given here summarize the changes in the mean phase function and linear polarization with changes in the real part of the complex index of refraction, n - ik, for k equals 0.01, the visible wavelength 0.55 micrometers, and the particle size distribution of the typical mature lunar soil 72141. A second figure is a similar index-phase surface, except with k equals 0.1. The index-phase surfaces from this survey are a first order description of scattering by lunar-like regoliths of spherical particles of arbitrary composition. They form the basis of functions that span a large range of parameter-space.

  17. Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment from lattice QCD

    DOE PAGES

    Blum, Thomas; Chowdhury, Saumitra; Hayakawa, Masashi; ...

    2015-01-07

    The form factor that yields the light-by-light scattering contribution to the muon anomalous magnetic moment is computed in lattice QCD+QED and QED. A non-perturbative treatment of QED is used and is checked against perturbation theory. The hadronic contribution is calculated for unphysical quark and muon masses, and only the diagram with a single quark loop is computed. Statistically significant signals are obtained. Initial results appear promising, and the prospect for a complete calculation with physical masses and controlled errors is discussed.

  18. Updates on the Optical Emission Spectroscopy and Thomson Scattering Investigations on the Helicon Plasma Experiment (HPX)

    NASA Astrophysics Data System (ADS)

    Duke-Tinson, Omar; Karama, Jackson; Azzari, Phillip; Royce, James; Page, Eric; Schlank, Carter; Sherman, Justin; Stutzman, Brooke; Zuniga, Jonathan

    2014-10-01

    HPX at the Coast Guard Academy Plasma Laboratory (CGAPL) have set up spectral probes to verify plasma mode transitions to the W-mode. These optical probes utilize movable filters, and ccd cameras to gather data at selected spectral frequency bands. Raw data collected will be used to measure the plasma's relative density, temperature, structure, and behavior during experiments. Direct measurements of the plasma's properties can be determined through modeling and by comparison with the state transition tables, using Optical Emission Spectroscopy (OES). The spectral probes will take advantage of HPX's magnetic field structure to define and measure the plasma's radiation temp as a function of time and space. In addition, the Thomson Scattering (TS) device will measure internal temperature and density data as the HPX plasma transitions through capacitive and inductive modes while developing into helicon plasma. Currently CGAPL is focused on building its laser beam transport and scattered light collection optical systems. Recently, HPX has acquired an Andor ICCD spectrometer for the spectral analysis. Data collected by the TS system will be logged in real time by CGAPL's Data Acquisition (DAQ) system with LabView remote access. Further progress on HPX will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY13.

  19. Nonlinear optical signals and spectroscopy with quantum light

    NASA Astrophysics Data System (ADS)

    Dorfman, Konstantin E.; Schlawin, Frank; Mukamel, Shaul

    2016-10-01

    Conventional nonlinear spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the quantum state of light as novel control knobs and through the variation of photon statistics by coupling to matter. An intuitive diagrammatic approach is presented for calculating ultrafast spectroscopy signals induced by quantum light, focusing on applications involving entangled photons with nonclassical bandwidth properties—known as "time-energy entanglement." Nonlinear optical signals induced by quantized light fields are expressed using time-ordered multipoint correlation functions of superoperators in the joint field plus matter phase space. These are distinct from Glauber's photon counting formalism which uses normally ordered products of ordinary operators in the field space. One notable advantage for spectroscopy applications is that entangled-photon pairs are not subjected to the classical Fourier limitations on the joint temporal and spectral resolution. After a brief survey of properties of entangled-photon pairs relevant to their spectroscopic applications, different optical signals, and photon counting setups are discussed and illustrated for simple multilevel model systems.

  20. A TECHNIQUE FOR THE STUDY OF SPHERULITE DEFORMATION: LIGHT SCATTERING MOVIES,

    DTIC Science & Technology

    TEST METHODS, POLYMERS), (*POLYMERS, CRYSTAL STRUCTURE), (*CRYSTALS, DEFORMATION), (* MOTION PICTURE CAMERAS, MONITORS), (*LASERS, GAS DISCHARGES), LIGHT, SCATTERING, SPHERES, POLYETHYLENE PLASTICS, RELAXATION TIME

  1. Particle sizing by measurement of forward-scattered light at two angles

    NASA Technical Reports Server (NTRS)

    Buchele, D. R.

    1983-01-01

    Fundamental and practical limitations to particle sizing by measurement of forward scattered light are presented. Methods to minimize the limitations are described. Two types of instruments are compared.

  2. Nanoparticle free polymer blends for light scattering films in liquid crystal displays

    NASA Astrophysics Data System (ADS)

    Takei, Satoshi; Mochiduki, Kazuhide; Kubo, Naoya; Yokoyama, Yoshiyuki

    2012-06-01

    This paper reports an approach using nanoparticle free polymer blends for light scattering films in liquid crystal displays. The ability to create the regularly structured circle of approximately 200 nm diameter in the light scattering film by blending two specified polymers with carboxylic acid groups and epoxy groups was demonstrated. The developed light scattering film based on thermosetting system indicated regularly structured nanomorphology, high light scattering rates of more than 3.9% at 300-600 nm of wavelength, and fast thermal cross-linking reaction at 150 °C and 60 s in thermosetting conditions for high productivity.

  3. 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.

  4. Light transmission channels in random scattering media (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cao, Hui

    2016-03-01

    Recently it has been shown that shaping the wavefront of an incident laser beam can significantly enhance the total transmission of light through strong scattering media [1]. This is done by coupling light to high transmission channels. However, optical absorption would modify such transmission channels. In a disordered system with uniform absorption, the maximal transmission channel changes from diffusive to ballistic-like transport [2]. This ballistic-like transport may enable new modes of imaging in absorbing media. If the absorption is distributed non-uniformly in space, the high transmission channels redirect the energy flows to circumvent the absorbing regions to minimize loss. Thus the attenuation of high transmission channels by inhomogeneous absorption becomes lower than that by homogeneous absorption [3]. Since the maximum transmission channel is the most efficient in bypassing the absorbing region, the ratio of its transmittance to the average transmittance increases with absorption, eventually exceeds the ratio without absorption. The finding that inhomogeneous absorption may have a weaker impact on open channels than homogeneous absorption is promising for practical applications. [1] S. M. Popoff, A. Goetschy, S. F. Liew, A. D. Stone, and H. Cao. Phys. Rev. Lett. 112, 133903 (2014). [2] S. F. Liew, S. M. Popoff, A. P. Mosk, W. L. Vos, and H. Cao. Phys. Rev. B 89, 224202 (2014). [3] S. F. Liew and H. Cao. Opt. Express 23, 11043 (2015).

  5. Attenuation, scattering, and depolarization of light by gold nanorods with silver shells

    NASA Astrophysics Data System (ADS)

    Khlebtsov, B. N.; Khanadeev, V. A.; Khlebtsov, N. G.

    2010-01-01

    Gold nanoparticles with silver nanoshells are obtained by synthesizing gold nanorods in a growing solution containing cetyltrimethylammonium bromide, subsequent separation in a concentration gradient of glycerol, and reduction of silver nitrate by ascorbic acid under alkaline conditions in the presence of polyvinylpyrrolidone. The formation of silver nanoshells was monitored by the shift of plasmon resonances of extinction and differential light scattering, by the appearance of characteristics peaks of silver in the energy dispersive X-ray (EDX) spectra of samples, by the data of transmission electron microscopy, and by visual changes in the color of colloids. The spectrum of the intensity ratio of the co- and cross-polarized compo- nents of light scattered by gold-silver nanorods is measured for the first time, and it is observed that the maximum is shifted by 80-100 nm compared to previously published spectra of gold nanorods (Khlebtsov et al., J. Phys. Chem. C 112, 12760 (2008)). The extinction and light scattering spectra are calculated by the method of separation of variables using the model of a confocal two-layer spheroid and these calculations are found to agree with spectral measurements. A method for determining the thickness of a silver nanolayer by the spectral shift of an extinction longitudinal resonance is described. The obtained data of optical spectroscopy and transmission electron microscopy and estimations of the mass of the deposited metal show that the aver-age thickness of the silver layer varies from 0.12 to 4 nm as the Ag/Au ratio changes from 2/80 to 90/80 μg/μg.

  6. Light Scattering Tests of Fundamental Theories of Transport Properties in the Critical Region

    NASA Technical Reports Server (NTRS)

    Gammon, R. W.; Moldover, M. R.

    1985-01-01

    The objective of this program is to measure the decay rates of critical density fluctuations in a simple fluid (xenon) very near its liquid-vapor critical point using laser light scattering and photon correlation spectroscopy. Such experiments have been severely limited on Earth by the presence of gravity which causes large density gradients in the sample when the compressibility diverges approaching the critical point. The goal is to measure decay rates deep in the critical region where the scaled wavevector is the order of 1000. This will require loading the sample to 0.01% of the critical density and taking data as close as 3 microKelvin to the critical temperature (Tc = 289.72 K). Other technical problems have to be addressed such as multiple scattering and the effect of wetting layers. The ability to avoid multiple scattering by using a thin sample (100 microns) was demonstrated, as well as a temperature history which can avoid wetting layers satisfactory temperature control and measurement, and accurate sample loading. Thus the questions of experimental art are solved leaving the important engineering tasks of mounting the experiment to maintain alignment during flight and automating the state-of-the-art temperature bridges for microcomputer control of the experiment.

  7. Spectroscopy of light and heavy quarks

    SciTech Connect

    Cooper, S.

    1986-11-01

    New results on various controversial light mesons are reviewed, including the glueball candidates f/sub 2/(1720) and eta(1460), the 1/sup + +/-0/sup - +/ mass ''coincidences'' f/sub 1/(1285)-eta(1275) and f/sub 1/(1420)-eta(1420), as well as evidence for the X(3100)..--> lambda..anti p+n..pi.. and the rho(1480)..-->..phi ..pi.., which have quantum numbers not allowed for q anti q. The ..gamma gamma -->..VV effects move out of the threshold region with data on ..gamma gamma --> omega..rho. Statistically weak data on GAMMA/sub ..gamma gamma../eta/sub c/ and the search for heavy quark P/sub 1/ states are presented. GAMMA/sub ee/, B/sub ..mu mu../, and GAMMA/sub tot/ for the UPSILON(1S), UPSILON(2S), and UPSILON(3S) are updated using new data and a consistent treatment of the radiative corrections for GAMMA/sub ee/. New data on the mass splittings of the chi/sub b/(2P) compare favorably with the scalar confinement model, which may however have new trouble. 150 refs., 43 figs.

  8. QUANTUM CONTROL OF LIGHT: From Slow Light and FAST CARS to Nuclear γ-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Scully, Marlan

    2007-06-01

    In recent work we have demonstrated strong coherent backward wave oscillation using forward propagating fields only. This surprising result is achieved by applying laser fields to an ultra-dispersive medium with proper chosen detunings to excite a molecular vibrational coherence that corresponds to a backward propagating wave [PRL, 97, 113001 (2006)]. The physics then has much in common with propagation of ultra-slow light. Applications of coherent scattering and remote sensing to the detection of bio and chemical pathogens (e.g., anthrax) via Coherent Anti-Raman Scattering together with Femtosecond Adaptive Spectroscopic Techniques (FAST CARS [Opt. Comm., 244, 423 (2005)]) will be discussed. Furthermore, the interplay between quantum optics (Dicke super and sub-radiant states) and nuclear physics (forward scattering of γ radiation) provides interesting problems and insights into the quantum control of scattered light [PRL, 96, 010501 (2005)].

  9. Research on the illumination model based on light scattering properties of steel surface

    NASA Astrophysics Data System (ADS)

    Liu, Yuanjiong; Kong, Jianyi; Xu, Pan; Liu, Cancan; Zheng, Guo

    2015-12-01

    Experimental scheme was designed based on the steel production process, surface optical characteristics and BRDF (Bidirectional Reflectance Distribution Function) illumination model theory. The relationship between the light incidence angle, surface roughness and laws of light scattering under a particular light-source conditions were found through a series of light scattering characteristics experiments for different steel plate surface. The results showed that there was an apparent specular reflection peak on steel surface. surface light scattering was influenced greatly by light incidence angle and surface roughness, and it showed the law of exponential distribution functions. Thus the improved semi-empirical light scattering mathematical model which based on roughness factor and surface Gaussian distribution of micro-plane components has been formed through non-linear model fitting and optimization. The surface illumination model has been proposed to accurately describe the light intensity distribution of steel plate surface and provide a theoretical method for the design of optimal imaging system.

  10. Analyzing cell structure and dynamics with confocal light scattering and absorption spectroscopic microscopy

    NASA Astrophysics Data System (ADS)

    Qiu, Le; Vitkin, Edward; Fang, Hui; Zaman, Munir M.; Andersson, Charlotte; Salahuddin, Saira; Modell, Mark D.; Freedman, Steven D.; Hanlon, Eugene B.; Itzkan, Irving; Perelman, Lev T.

    2007-02-01

    We recently developed a new microscopic optical technique capable of noninvasive analysis of cell structure and cell dynamics on the submicron scale [1]. It combines confocal microscopy, a well-established high-resolution microscopic technique, with light scattering spectroscopy (LSS) and is called confocal light absorption and scattering spectroscopic (CLASS) microscopy. CLASS microscopy requires no exogenous labels and is capable of imaging and continuously monitoring individual viable cells, enabling the observation of cell and organelle functioning at scales on the order of 100 nm. To test the ability of CLASS microscopy to monitor cellular dynamics in vivo we performed experiments with human bronchial epithelial cells treated with DHA and undergoing apoptosis. The treated and untreated cells show not only clear differences in organelle spatial distribution but time sequencing experiments on a single cell show disappearance of certain types of organelles and change of the nuclear shape and density with the progression of apoptosis. In summary, CLASS microscopy provides an insight into metabolic processes within the cell and opens doors for the noninvasive real-time assessment of cellular dynamics. Noninvasive monitoring of cellular dynamics with CLASS microscopy can be used for a real-time dosimetry in a wide variety of medical and environmental applications that have no immediate observable outcome, such as photodynamic therapy, drug screening, and monitoring of toxins.

  11. Dynamics of density fluctuations of a glass-forming epoxy resin revealed by Brillouin light scattering

    NASA Astrophysics Data System (ADS)

    Fioretto, D.; Comez, L.; Socino, G.; Verdini, L.; Corezzi, S.; Rolla, P. A.

    1999-02-01

    Brillouin light scattering is used for studying the spectrum of density fluctuations of the glass-forming epoxy resin diglycidyl ether of bisphenol-A. Spectra at different temperatures ranging from the glassy to the liquid phase are obtained from a direct subtraction of depolarized from polarized spectra. In addition to the structural relaxation, evidence is given of a fast secondary relaxation process, which affects Brillouin spectra also at temperatures lower than that of the glass transition Tg. For the elaboration of isotropic spectra, we exploit the possibility of using the same relaxation function gained from dielectric spectra taken from the same sample. The temperature behavior of the relaxation strength shows the existence of an onset for the structural relaxation, located at a temperature about 93 K higher than Tg, consistent with the results of previous dielectric spectroscopy and depolarized light scattering investigations. The role of secondary relaxations of intramolecular nature in the mode-coupling analysis of real glass formers is also discussed.

  12. Liquid crystal physical gel formed by cholesteryl stearate for light scattering display material.

    PubMed

    Leaw, W L; Mamat, C R; Triwahyono, S; Jalil, A A; Bidin, N

    2016-12-01

    A liquid crystal physical gel was prepared by the self-assembly of cholesteryl stearate in a nematic liquid crystal, 4-cyano-4'-pentylbiphenyl. The electro-optical properties were tuned by varying the gelator concentration and the gelation conditions. Polarized optical microscopy revealed that cholesteric cholesteryl stearate induced chiral nematic phase in 4-cyano-4'-pentylbiphenyl during the gelation process. As a result, a plate-like gel structure consisting of spherical micropores was formed, as observed by scanning electron microscopy. Electron spin resonance spectroscopy showed that the liquid crystal director orientations in these macrophase-separated structures were massively randomised. For these reasons, the liquid crystal physical gel generated a strong light scattering effect. For 48.0wt% cholesteryl stearate gelled 4-cyano-4'-pentylbiphenyl, the turbid appearance could be switched to a transparent state using a 5.0V alternating current. The response time was about 3.7μs. This liquid crystal physical gel has potential for use in light scattering electro-optical displays.

  13. Focusing light through scattering media by full-polarization digital optical phase conjugation.

    PubMed

    Shen, Yuecheng; Liu, Yan; Ma, Cheng; Wang, Lihong V

    2016-03-15

    Digital optical phase conjugation (DOPC) is an emerging technique for focusing light through or within scattering media such as biological tissue. Since DOPC systems are based on time reversal, they benefit from collecting as much information about the scattered light as possible. However, existing DOPC techniques record and subsequently phase-conjugate the scattered light in only a single-polarization state, limited by the operating principle of spatial light modulators. Here, we develop the first, to the best of our knowledge, full-polarization DOPC system that records and phase-conjugates scattered light along two orthogonal polarizations. When focusing light through thick scattering media, such as 2 mm and 4 mm-thick chicken breast tissue, our full-polarization DOPC system on average doubles the focal peak-to-background ratio achieved by single-polarization DOPC systems and improves the phase-conjugation fidelity.

  14. Focusing light through scattering media by full-polarization digital optical phase conjugation

    PubMed Central

    Shen, Yuecheng; Liu, Yan; Ma, Cheng; Wang, Lihong V.

    2016-01-01

    Digital optical phase conjugation (DOPC) is an emerging technique for focusing light through or within scattering media such as biological tissue. Since DOPC systems are based on time reversal, they benefit from collecting as much information about the scattered light as possible. However, existing DOPC techniques record and subsequently phase-conjugate the scattered light in only a single polarization state, limited by the operating principle of spatial light modulators. Here, we develop the first full-polarization DOPC system which records and phase-conjugates scattered light along two orthogonal polarizations. When focusing light through thick scattering media, such as 2 mm and 4 mm thick chicken breast tissue, our full-polarization DOPC system on average doubles the focal peak-to-background ratio achieved by single-polarization DOPC systems and improves the phase conjugation fidelity. PMID:26977651

  15. [Research on the application of response variable transform method in high scattering medium with near-infrared spectroscopy].

    PubMed

    Peng, Dan; Xu, Ke-Xin

    2010-02-01

    In the present paper, a new method named response variable transform (RVT) is proposed to reduce the effect of scattering in the NIR spectroscopy measurement. In the RVT method, the rates of the change in light intensity at different spatial positions with the concentration of the investigated composition are firstly sampled. Then, based on the sampled changing rates of light intensity, the absorption coefficients, which are used as new response variable, are calculated using the inverse adding-double (IAD) algorithm. Finally, through the partial least squares (PLS) regression, the calibration models for the investigated compositions are established using these new response variables. To validate the feasibility and effectiveness of the proposed method, the RVT method is applied to reduce the effect of scattering during the process of composition concentration measurement in milk. First, the relationships between the absorption coefficient and the concentrations of major compositions including fat and protein are analyzed. Then, with Monte Carlo simulations for different concentration levels of fat and protein, the influence of scattering on the relationship between the absorbency and the concentration is investigated and verified. Finally, for comparison, both the RVT method and the traditional preprocessing techniques are used to reduce the effect of scattering during the process of prediction model establishment. Experimental results showed that the prediction precision for fat and protein with the RVT method is increased by up to 33.9% and 46.5% than that with multiplicative signal correction (MSC) algorithm, and the prediction precision for fat and protein with the RVT method is increased by up to 55.9% and 33.7% than that with standard normal variate (SNV) algorithm, which also indicates that the RVT method is an effective method for eliminating the interference of scattering in the NIR spectroscopy measurement.

  16. A hybrid MC-FEM model for analysis of light propagation in highly scattering medium

    NASA Astrophysics Data System (ADS)

    Kurihara, Kazuki; Wu, Xue; Okada, Eiji; Dehghani, Hamid

    2013-06-01

    The hemodynamic change related to the brain activation can be located by the diffuse optical tomography (DOT) using the near-infrared spectroscopy (NIRS) signals and the spatial sensitivity profiles (SSP). Monte Carlo (MC) method and finite element method (FEM) have been used to predict the SSPs. The computation time for MC method is much longer than that for the FEM, however, the accurate solution in the region close to the light source cannot be obtained by FEM solutions of the diffusion equation. In this study, a hybrid MC-FEM model is proposed for fast and accurate simulation of light propagation in a highly scattering medium. In the hybrid model, the solution in the region close to the light source is calculated by the MC method whereas that in the region far from the light source is calculated by the FEM. The solutions by the FEM in hemispherical models were compared with thoseby the MC method to determine the region in which diffusion approximation does not hold and the number of photons for the MC method for the hybrid model. The results demonstratethat theproposed hybrid model can calculatethe accurate solutionswithin reasonable computation time for a multi-layered model.

  17. Light induced changes in Raman scattering of carotenoid molecules in Photosystem I particles

    NASA Astrophysics Data System (ADS)

    Andreeva, Atanaska; Abarova, Silviya; Stoitchkova, Katerina; Velitchkova, Maya

    2007-03-01

    The photosynthetic antenna systems are able to regulate the light energy harvesting under different light conditions by dynamic changes in their protein structure protecting the reaction center complexes. The changes modulate the electronic structure of the main antenna pigments (chlorophylls and carotenoids) and distort the characteristic planar structure of carotenoids, allowing their forbidden out of plane vibrations. Electronic absorption and low-temperature resonance Raman spectroscopy were used to study the changes in composition and spectral properties of the major carotenoids in spinach Photosystem I particles due to high light treatment. The duration of the applied intensity of the white light (1800 μE m -2 s -1) was 30, 60 and 120 minutes. We used Raman scattering in an attempt to recognize the type and conformation of photobleached carotenoid molecules. The resonance Raman spectra were measured at 488 and 514.5 nm, coinciding with the absorption maximum positions of the carotenoids neoxanthin and lutein, correspondingly. The results revealed nearly a full photobleaching of the long wavelength lutein molecules, whereas the bleaching of neoxantin molecules is negligible. The involvement of these changes in the photoprotection and photoinactivation of the Photosystem I particles was discussed.

  18. Frequency-modulated light scattering interferometry used for assessment of optical properties in turbid media

    NASA Astrophysics Data System (ADS)

    Mei, Liang; Somesfalean, Gabriel; Svanberg, Sune

    2013-02-01

    Frequency-modulated light scattering interferometry, which employs a frequency-modulated coherent light source and examines the intensity fluctuation of the resulting scattered light using a heterodyne detection scheme, was utilized to evaluate the optical properties of liquid phantoms made of Intralipid® and Indian ink. Based on the diffusion theory, nonlinear fits to the power spectrum of the heterodyne-detected light intensity are performed and discussed in detail, and the optical properties of liquid phantoms are consequently retrieved.

  19. Light scattering change precedes loss of cerebral adenosine triphosphate in a rat global ischemic brain model.

    PubMed

    Kawauchi, Satoko; Sato, Shunichi; Ooigawa, Hidetoshi; Nawashiro, Hiroshi; Ishihara, Miya; Kikuchi, Makoto

    2009-08-14

    Measurement of intrinsic optical signals (IOSs) is an attractive technique for monitoring tissue viability in brains since it enables noninvasive, real-time monitoring of morphological characteristics as well as physiological and biochemical characteristics of tissue. We previously showed that light scattering signals reflecting cellular morphological characteristics were closely related to the IOSs associated with the redox states of cytochrome c oxidase in the mitochondrial respiratory chain. In the present study, we examined the relationship between light scattering and energy metabolism. Light scattering signals were transcranially measured in rat brains after oxygen and glucose deprivation, and the results were compared with concentrations of cerebral adenosine triphosphate (ATP) measured by luciferin-luciferase bioluminescence assay. Electrophysiological signal was also recorded simultaneously. After starting saline infusion, EEG activity ceased at 108+/-17s, even after which both the light scattering signal and ATP concentration remained at initial levels. However, light scattering started to change in three phases at 236+/-15s and then cerebral ATP concentration started to decrease at about 260s. ATP concentration significantly decreased during the triphasic scattering change, indicating that the start of scattering change preceded the loss of cerebral ATP. The mean time difference between the start of triphasic scattering change and the onset of ATP loss was about 24s in the present model. DC potential measurement showed that the triphasic scattering change was associated with anoxic depolarization. These findings suggest that light scattering signal can be used as an indicator of loss of tissue viability in brains.

  20. Influence of forward and multiple light scatter on the measurement of beam attenuation in highly scattering marine environments.

    PubMed

    Piskozub, Jacek; Stramski, Dariusz; Terrill, Eric; Melville, W Kendall

    2004-08-20

    Using three-dimensional Monte Carlo radiative transfer simulations, we examine the effect of beam transmissometer geometry on the relative error in the measurement of the beam-attenuation coefficient in an aquatic environment characterized by intense light scattering, especially within submerged bubble clouds entrained by surface-wave breaking. We discuss the forward-scattering error associated with the detection of photons scattered at small angles (< 1 degrees) and the multiple-scattering error associated with the detection of photons scattered more than once along the path length of the instrument. Several scattering phase functions describing bubble clouds at different bubble void fractions in the water are considered. Owing to forward-scattering error, a beam-attenuation meter (beam transmissometer) with a half-angle of receiver acceptance of 1.0 degrees and a path length of 0.1 m can underestimate the true beam attenuation within the bubble cloud by more than 50%. For bubble clouds with a beam attenuation of as much as 100 m(-1), the multiple-scattering error is no more than a few percent. These results are compared with simulations for some example phase functions that are representative of other scattering regimes found in natural waters. The forward-scattering error for the Petzold phase function of turbid waters is 16% for a typical instrument geometry, whereas for the Henyey-Greenstein phase function with the asymmetry parameter of 0.7 and 0.9 the error range is 8-28%.

  1. 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.

  2. Sideways scattering in double resonant plasmonic nanostructures for light harvesting applications.

    PubMed

    Achermann, Marc

    2016-12-26

    Numerical simulations of light scattering by elongated metal nanoparticles in an asymmetric arrangement show resonant scattering in two near-infrared wavelength ranges associated with different surface plasmon modes. The main scattering directions of the two plasmon modes are in opposite diagonal directions and almost perpendicular to each other. At wavelengths in-between the two plasmon resonances our simulations showed for the first time strong scattering at approximately ± 90°, which is parallel to the incident electric field direction. Since enhanced sideways scattering exists over a significant wavelength range, the proposed nanoparticle assemblies could be beneficial for light harvesting applications such as solar windows.

  3. Continuous-wave stimulated Brillouin spectroscopy in scattering media at 780 nm (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Remer, Itay; Billenca, Alberto

    2016-03-01

    Quantitative probing of the mechanical properties of scattering media by Brillouin spectroscopy is an emerging field of research. At present, Brillouin spectrometers typically detect spontaneous Brillouin backscattered signals from the sample using setups that comprise virtually imaged phased arrays (VIPAs) cascaded in cross-axis configuration or heated molecular absorption cells prior to the VIPA. These experimental arrangements are necessary in order to significantly suppress the strong elastic scattering background from the medium. In this talk, we present a different approach for Brillouin spectroscopy of scattering matter based on stimulated Brillouin scattering (SBS) amplification. Unlike spontaneous Brillouin scattering, SBS amplification does not show elastic scattering background due to the resonant nature of the amplification process, thereby providing excellent spectral contrast. We demonstrate that the use of two continuous-wave distributed feedback lasers at 780 nm in a counter-propagating SBS amplifier geometry is useful for acquiring high signal-to-noise ratio SBS spectra of Intralipid solutions at concentrations that yield up to ~3 scattering events for photons propagating through the sample. Potential applications of SBS spectroscopy in mechanical characterization of thin tissue sections and biopolymers will be discussed.

  4. Magnetic Modes in Rare Earth Perovskites: A Magnetic-Field-Dependent Inelastic Light Scattering study.

    PubMed

    Saha, Surajit; Cao, Bing-Chen; Motapothula, M; Cong, Chun-Xiao; Sarkar, Tarapada; Srivastava, Amar; Sarkar, Soumya; Patra, Abhijeet; Ghosh, Siddhartha; Ariando; Coey, J M D; Yu, Ting; Venkatesan, T

    2016-11-15

    Here, we report the presence of defect-related states with magnetic degrees of freedom in crystals of LaAlO3 and several other rare-earth based perovskite oxides using inelastic light scattering (Raman spectroscopy) at low temperatures in applied magnetic fields of up to 9 T. Some of these states are at about 140 meV above the valence band maximum while others are mid-gap states at about 2.3 eV. No magnetic impurity could be detected in LaAlO3 by Proton-Induced X-ray Emission Spectroscopy. We, therefore, attribute the angular momentum-like states in LaAlO3 to cationic/anionic vacancies or anti-site defects. Comparison with the other rare earth perovskites leads to the empirical rule that the magnetic-field-sensitive transitions require planes of heavy elements (e.g. lanthanum) and oxygen without any other light cations in the same plane. These magnetic degrees of freedom in rare earth perovskites with useful dielectric properties may be tunable by appropriate defect engineering for magneto-optic applications.

  5. Magnetic Modes in Rare Earth Perovskites: A Magnetic-Field-Dependent Inelastic Light Scattering study

    NASA Astrophysics Data System (ADS)

    Saha, Surajit; Cao, Bing-Chen; Motapothula, M.; Cong, Chun-Xiao; Sarkar, Tarapada; Srivastava, Amar; Sarkar, Soumya; Patra, Abhijeet; Ghosh, Siddhartha; Ariando; Coey, J. M. D.; Yu, Ting; Venkatesan, T.

    2016-11-01

    Here, we report the presence of defect-related states with magnetic degrees of freedom in crystals of LaAlO3 and several other rare-earth based perovskite oxides using inelastic light scattering (Raman spectroscopy) at low temperatures in applied magnetic fields of up to 9 T. Some of these states are at about 140 meV above the valence band maximum while others are mid-gap states at about 2.3 eV. No magnetic impurity could be detected in LaAlO3 by Proton-Induced X-ray Emission Spectroscopy. We, therefore, attribute the angular momentum-like states in LaAlO3 to cationic/anionic vacancies or anti-site defects. Comparison with the other rare earth perovskites leads to the empirical rule that the magnetic-field-sensitive transitions require planes of heavy elements (e.g. lanthanum) and oxygen without any other light cations in the same plane. These magnetic degrees of freedom in rare earth perovskites with useful dielectric properties may be tunable by appropriate defect engineering for magneto-optic applications.

  6. Magnetic Modes in Rare Earth Perovskites: A Magnetic-Field-Dependent Inelastic Light Scattering study

    PubMed Central

    Saha, Surajit; Cao, Bing-Chen; Motapothula, M.; Cong, Chun-Xiao; Sarkar, Tarapada; Srivastava, Amar; Sarkar, Soumya; Patra, Abhijeet; Ghosh, Siddhartha; Ariando; Coey, J. M. D.; Yu, Ting; Venkatesan, T.

    2016-01-01

    Here, we report the presence of defect-related states with magnetic degrees of freedom in crystals of LaAlO3 and several other rare-earth based perovskite oxides using inelastic light scattering (Raman spectroscopy) at low temperatures in applied magnetic fields of up to 9 T. Some of these states are at about 140 meV above the valence band maximum while others are mid-gap states at about 2.3 eV. No magnetic impurity could be detected in LaAlO3 by Proton-Induced X-ray Emission Spectroscopy. We, therefore, attribute the angular momentum-like states in LaAlO3 to cationic/anionic vacancies or anti-site defects. Comparison with the other rare earth perovskites leads to the empirical rule that the magnetic-field-sensitive transitions require planes of heavy elements (e.g. lanthanum) and oxygen without any other light cations in the same plane. These magnetic degrees of freedom in rare earth perovskites with useful dielectric properties may be tunable by appropriate defect engineering for magneto-optic applications. PMID:27845368

  7. Molecular characterization of multivalent bioconjugates by size-exclusion chromatography with multiangle laser light scattering.

    PubMed

    Pollock, Jacob F; Ashton, Randolph S; Rode, Nikhil A; Schaffer, David V; Healy, Kevin E

    2012-09-19

    The degree of substitution and valency of bioconjugate reaction products are often poorly judged or require multiple time- and product-consuming chemical characterization methods. These aspects become critical when analyzing and optimizing the potency of costly polyvalent bioactive conjugates. In this study, size-exclusion chromatography with multiangle laser light scattering was paired with refractive index detection and ultraviolet spectroscopy (SEC-MALS-RI-UV) to characterize the reaction efficiency, degree of substitution, and valency of the products of conjugation of either peptides or proteins to a biopolymer scaffold, i.e., hyaluronic acid (HyA). Molecular characterization was more complete compared to estimates from a protein quantification assay, and exploitation of this method led to more accurate deduction of the molecular structures of polymer bioconjugates. Information obtained using this technique can improve macromolecular engineering design principles and help to better understand multivalent macromolecular interactions in biological systems.

  8. Temperature dependence of Brillouin light scattering spectra of acoustic phonons in silicon

    SciTech Connect

    Olsson, Kevin S.; Klimovich, Nikita; An, Kyongmo; Sullivan, Sean; Weathers, Annie; Shi, Li E-mail: elaineli@physics.utexas.edu; Li, Xiaoqin E-mail: elaineli@physics.utexas.edu

    2015-02-02

    Electrons, optical phonons, and acoustic phonons are often driven out of local equilibrium in electronic devices or during laser-material interaction processes. The need for a better understanding of such non-equilibrium transport processes has motivated the development of Raman spectroscopy as a local temperature sensor of optical phonons and intermediate frequency acoustic phonons, whereas Brillouin light scattering (BLS) has recently been explored as a temperature sensor of low-frequency acoustic phonons. Here, we report the measured BLS spectra of silicon at different temperatures. The origins of the observed temperature dependence of the BLS peak position, linewidth, and intensity are examined in order to evaluate their potential use as temperature sensors for acoustic phonons.

  9. Temperature dependence of Brillouin light scattering spectra of acoustic phonons in silicon

    NASA Astrophysics Data System (ADS)

    Olsson, Kevin S.; Klimovich, Nikita; An, Kyongmo; Sullivan, Sean; Weathers, Annie; Shi, Li; Li, Xiaoqin

    2015-02-01

    Electrons, optical phonons, and acoustic phonons are often driven out of local equilibrium in electronic devices or during laser-material interaction processes. The need for a better understanding of such non-equilibrium transport processes has motivated the development of Raman spectroscopy as a local temperature sensor of optical phonons and intermediate frequency acoustic phonons, whereas Brillouin light scattering (BLS) has recently been explored as a temperature sensor of low-frequency acoustic phonons. Here, we report the measured BLS spectra of silicon at different temperatures. The origins of the observed temperature dependence of the BLS peak position, linewidth, and intensity are examined in order to evaluate their potential use as temperature sensors for acoustic phonons.

  10. Temperature Dependence of Brillouin Light Scattering Spectra of Acoustic Phonons in Silicon

    NASA Astrophysics Data System (ADS)

    Somerville, Kevin; Klimovich, Nikita; An, Kyongmo; Sullivan, Sean; Weathers, Annie; Shi, Li; Li, Xiaoqin

    2015-03-01

    Thermal management represents an outstanding challenge in many areas of technology. Electrons, optical phonons, and acoustic phonons are often driven out of local equilibrium in electronic devices or during laser-material interaction processes. Interest in non-equilibrium transport processes has motivated the development of Raman spectroscopy as a local temperature sensor of optical phonons and intermediate frequency acoustic phonons, whereas Brillouin light scattering (BLS) has recently been explored as a temperature sensor of low-frequency acoustic phonons. Here, we report temperature dependent BLS spectra of silicon, with Raman spectra taken simultaneously for comparison. The origins of the observed temperature dependence of the BLS peak position, linewidth, and intensity are examined in order to evaluate their potential use as temperature sensors for acoustic phonons. We determine that the integrated BLS intensity can be used measure the temperature of specific acoustic phonon modes. This work is supported by National Science Foundation (NSF) Thermal Transport Processes Program under Grant CBET-1336968.

  11. Use of dynamic light scattering to determine second virial coefficient in a semidilute concentration regime.

    PubMed

    Yadav, Sandeep; Scherer, Thomas M; Shire, Steven J; Kalonia, Devendra S

    2011-04-15

    The present work discusses an alternative procedure to obtain static light scattering (SLS) parameters in a dilute and semidilute concentration regime from a dynamic light scattering (DLS) instrument that uses an avalanche photodiode (APD) for recording the scattered intensity signal. An APD enables one to perform both SLS and DLS measurements by photon counting and photon correlation, respectively. However, due to the associated recovery time, the APDs are susceptible to saturation (above 1000 kcps), which may limit the measurements in systems that scatter too much light. We propose an alternative way of obtaining the SLS parameters with instruments that use APD for recording signal intensities.

  12. Doppler effect's contribution to ultrasonic modulation of multiply scattered coherent light: Monte Carlo modeling.

    PubMed

    Elazar, Jovan M; Steshenko, Oleg

    2008-01-15

    Modulation of light by ultrasound in turbid media is investigated by modified public domain software based on the Monte Carlo algorithm. Apart from the recognized modulation mechanisms, originating in scatterers' displacements and refractive index modulation, an additional mechanism, evolving from Doppler shift during photon scattering, is considered. Comparison of the relative contributions from all three mechanisms to light modulation by ultrasound is performed for different medium scattering properties and ultrasound frequencies. Refractive index modulation remains the strongest mechanism for light modulation by ultrasound, but for high ultrasound frequencies and for large scattering coefficients the Doppler effect can become dominant.

  13. Small-angle light scattering from polymer-dispersed liquid-crystal films

    SciTech Connect

    Loiko, V. A. Maschke, U.; Zyryanov, V. Ya.; Konkolovich, A. V.; Misckevich, A. A.

    2008-10-15

    A method is developed for modeling and computing the angular distribution of light scattered forward from a single-layer polymer-dispersed liquid-crystal (PDLC) film. The method is based on effective-medium approximation, anomalous diffraction approximation, and far-field single-scattering approximation. The angular distribution of forward-scattered light is analyzed for PDLC films with droplet size larger than the optical wavelength. The method can be used to study field-and temperature-induced phase transitions in LC droplets with cylindrical symmetry by measuring polarized scattered light intensity.

  14. Stimulated concentration (diffusion) light scattering on nanoparticles in a liquid suspension

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    A nonlinear growth of the light scattering intensity has been observed and the frequency shift of the spectral line of scattered light has been measured in light backscattered in suspensions of diamond and latex nanoparticles in water. The shift corresponds to the HWHM of the line of spontaneous scattering on particles. We may conclude that there exists stimulated concentration (diffusion) light scattering on variations of the particle concentration, which is also called the stimulated Mie scattering. In a fibre probe scheme, the growth of the shift of the scattered spectral line is observed with an increase in the exciting beam power. The variation of the frequency shift with an increase in the exciting power is explained by convection in liquid.

  15. Coherence Effects in Light Propagation in Scattering and in Spectroscopy

    DTIC Science & Technology

    2005-12-01

    Gaussian Schell - model Beams Propagating in Atmospheric Turbulence", Opt. Lett. 28...generated by an electromagnetic Gaussian Schell - model source which propagates through atmospheric turbulence tends to its value at the source plane with...polarization on propagation . We illustrate the results by a numerical example relating to an electromagnetic Gaussian Schell - model beam. 17 51. H.

  16. Characterization of Mixed Polypeptide Colloidal Particles by Light Scattering

    NASA Astrophysics Data System (ADS)

    Shuman, Hannah E.; Gaeckle, Grace K.; Gavin, John; Holland, Nolan B.; Streletzky, Kiril A.

    2014-03-01

    Temperature-dependent polymer surfactants have been developed by connecting three elastin-like polypeptide (ELP) chains to a charged protein domain (foldon), forming a three-armed star polymer. At low temperatures the polymer is soluble, while at higher temperatures it forms micelles. The behavior of mixtures of the three-armed star ELP (E20-Foldon) and H40-Linear ELP chains was analyzed under different salt and protein concentrations and various foldon to linear ELP ratio using Depolarized Dynamic Light Scattering. It was expected that under certain conditions the pure E20-Foldon would form spherical micelles, which upon adding the linear ELP would change in size and possibly shape. The pure E20-Foldon indeed formed largely spherical micelles with Rh of 10-20nm in solutions with 15-100mM salt and protein concentration between 10 μM and 100 μM. For the mixtures of 50 μM E20-Foldon and varying concentrations of H40-Linear in 25mM of salt, it was discovered that low and high H40-Linear concentration (4 μM and 50 μM) had only one transition. For the mixtures with of 10 and 25 μM of H40-Linear the two distinct transition temperatures were observed by spectrophotometry. The first transition corresponded to significantly elongated diffusive particles of apparent Rh of 30-50nm, while the second transition corresponded to slightly anisotropic diffusive particles with apparent Rh of about 20nm. At all H40-Linear concentrations studied, diffusive particles were seen above the second transition. Their radius and ability to depolarize light increased with the increase of H40-Linear concentration.

  17. Linear correlation between bacterial overexpression of recombinant peptides and cell light scatter.

    PubMed Central

    Lavergne-Mazeau, F; Maftah, A; Cenatiempo, Y; Julien, R

    1996-01-01

    Fusion of multiple copies of a test peptide leads to insoluble inclusion bodies. Their presence within bacteria increases either forward-angle light scattering or, to a lesser extent, right-angle light scattering. A linear correlation has been established between cell forward-angle scattering and the level of overexpression of atrial natriuretic peptide. The correlation is valid only for unlysed cells and is protein product specific. PMID:8702299

  18. Dynamic light scattering of xanthan gum biopolymer in colloidal dispersion.

    PubMed

    Rahdar, Abbas; Almasi-Kashi, Mohammad

    2016-09-01

    The dynamical properties of nanogels of xanthan gum (XG) with hydrodynamic radius controlled in a size range from 5 nm to 35 nm, were studied at the different XG concentrations in water/sodium bis-2-ethylhexyl-sulfosuccinate (AOT)/decane reverse micelles (RMs) vs. mass fraction of nano-droplet (MFD) at W = 40, using dynamic light scattering (DLS). The diffusion study of nanometer-sized droplets by DLS technique indicated that enhancing concentration of the XG polysaccharide resulted in exchanging the attractive interaction between nano-gels to repulsive interaction, as the mass fraction of nano-droplets increased. The reorientation time (τr ) of water nanodroplets decreased with MFD for water-in-oil AOT micro-emulsion comprising high concentration (0.0000625) of XG. On the other hand, decreasing concentration of biopolymer led to increasing the rotational correlation time of water nanodroplets with MFD. In conclusion, a single relaxation curve was observed for AOT inverse microemulsions containing different XG concentrations. Furthermore, the interaction between nanogels was changed from attractive to repulsive versus concentration of XG in the AOT RMs.

  19. Physiological and pathological clinical conditions and light scattering in brain

    NASA Astrophysics Data System (ADS)

    Kurata, Tsuyoshi; Iwata, Sachiko; Tsuda, Kennosuke; Kinoshita, Masahiro; Saikusa, Mamoru; Hara, Naoko; Oda, Motoki; Ohmae, Etsuko; Araki, Yuko; Sugioka, Takashi; Takashima, Sachio; Iwata, Osuke

    2016-08-01

    MRI of preterm infants at term commonly reveals subtle brain lesions such as diffuse white matter injury, which are linked with later cognitive impairments. The timing and mechanism of such injury remains unclear. The reduced scattering coefficient of near-infrared light (μs’) has been shown to correlate linearly with gestational age in neonates. To identify clinical variables associated with brain μs’, 60 preterm and full-term infants were studied within 7 days of birth. Dependence of μs’ obtained from the frontal head on clinical variables was assessed. In the univariate analysis, smaller μs’ was associated with antenatal glucocorticoid, emergency Caesarean section, requirement for mechanical ventilation, smaller gestational age, smaller body sizes, low 1- and 5-minute Apgar scores, higher cord blood pH and PO2, and higher blood HCO3‑ at the time of study. Multivariate analysis revealed that smaller gestational age, requirement for mechanical ventilation, and higher HCO3‑ at the time of study were correlated with smaller μs’. Brain μs’ depended on variables associated with physiological maturation and pathological conditions of the brain. Further longitudinal studies may help identify pathological events and clinical conditions responsible for subtle brain injury and subsequent cognitive impairments following preterm birth.

  20. An ultra-efficient energy transfer beyond plasmonic light scattering

    SciTech Connect

    Fu, Sze-Ming; Zhong, Yan-Kai; Lin, Albert

    2014-11-14

    The energy transfer between nano-particles is of great importance for, solar cells, light-emitting diodes, nano-particle waveguides, and other photonic devices. This study shows through novel design and algorithm optimization, the energy transfer efficiency between plasmonic and dielectric nano-particles can be greatly improved. Using versatile designs including core-shell wrapping, supercells and dielectric mediated plasmonic scattering, 0.05 dB/μm attenuation can be achieved, which is 20-fold reduction over the baseline plasmonic nano-particle chain, and 8-fold reduction over the baseline dielectric nano-particle chain. In addition, it is also found that the dielectric nano-particle chains can actually be more efficient than the plasmonic ones, at their respective optimized geometry. The underlying physics is that although plasmonic nano-particles provide stronger coupling and field emission, the effect of plasmonic absorption loss is actually more dominant resulting in high attenuation. Finally, the group velocity for all design schemes proposed in this work is shown to be maintained above 0.4c, and it is found that the geometry optimization for transmission also boosts the group velocity.

  1. Speckle size of light scattered from 3D rough objects.

    PubMed

    Zhang, Geng; Wu, Zhensen; Li, Yanhui

    2012-02-13

    From scalar Helmholtz integral relation and by coordinate system transformation, this paper begins with a derivation of the far-zone speckle field in the observation plane perpendicular to the scattering direction from an arbitrarily shaped conducting rough object illuminated by a plane wave illumination, followed by the spatial correlation function of the speckle intensity to obtain the speckle size from the objects. Especially, the specific expressions for the speckle sizes of light backscattered from spheres, cylinders and cones are obtained in detail showing that the speckle size along one direction in the observation plane is proportional to the incident wavelength and the distance between the object and the observation plane, and is inverse proportional to the maximal illuminated dimension of the object parallel to the direction. In addition, the shapes of the speckle of the rough objects with different shapes are different. The investigation on the speckle size in this paper will be useful for the statistical properties of speckle from complicated rough objects and the speckle imaging to target detection and identification.

  2. RBC Aggregation Effect on Light Scattering from Blood.

    NASA Astrophysics Data System (ADS)

    Shvartsman, L. D.; Fine, Ilya

    2000-03-01

    We consider a number of diffusive and transport models of light transmission through whole blood. Single erythrocytes and their aggregates are considered to be the main centers of scattering in the red - near infrared spectral region. The shape and the size of aggregates change in time due to blood flow changes. Two important particular cases of time dependencies of blood flow have been considered, i.e.: the pulsatile dependence simulating the regular heartbeats and the sudden stop corresponding to the vessel occlusion. Various assumptions on aggregate geometry have been made and the results have been compared with the results of in vivo and in vitro optical transmission measurements. Time evolution of the optical transmission after vessel occlusion looks differently for various wavelengths. Based on the comparison of predicted and observed time dependencies of optical transmission, the optimal model of RBC aggregates geometry has been chosen. The resulting dependencies may serve as a basis for both a new explanation of the nature of pulsatile signal in pulse oximetry, and a physical basis for a number of novel non-invasive optical measurements of blood parameters.

  3. Fringe visibility of multimode laser light scattered through turbid water.

    PubMed

    Swanson, N L; Pham, C N; VanWinkle, D H

    1997-12-20

    Several years ago Swanson [Proc. SPIE 1750, 397 (1992)] performed a simple Michelson interferometric determination of the coherence length of a multimode argon-ion laser after the light passed through a tank of water. As colloidal particles were added to the water the observed coherence length (as measured by twice the distance the mirror moved for fringes to disappear) decreased. Subsequently, a series of careful experiments were performed with a single-mode laser to more accurately measure this change. In these experiments it was found that the 1.5-MHz width of the 514.5-nm line of a single-mode argon-ion laser broadened by as much as 1.3 +/- 0.2 MHz when small colloidal particles were added. At first glance such a broadening should not have resulted in any discernible change in the original Michelson experiment because the gain curve for the multimode laser is of the order of a few gigahertz. The zeros in the fringe visibility function depend on the spectral characteristics of the modes. Upon scattering, the spectral characteristics of the individual laser modes change from Voigt functions, containing both Lorentzian and Gaussian components, to primarily Gaussian. It is this change in the statistical properties of the modes, not the broadening, that accounts for the change in the fringe visibility for a multimode source.

  4. Maximum likelihood techniques applied to quasi-elastic light scattering

    NASA Technical Reports Server (NTRS)

    Edwards, Robert V.

    1992-01-01

    There is a necessity of having an automatic procedure for reliable estimation of the quality of the measurement of particle size from QELS (Quasi-Elastic Light Scattering). Getting the measurement itself, before any error estimates can be made, is a problem because it is obtained by a very indirect measurement of a signal derived from the motion of particles in the system and requires the solution of an inverse problem. The eigenvalue structure of the transform that generates the signal is such that an arbitrarily small amount of noise can obliterate parts of any practical inversion spectrum. This project uses the Maximum Likelihood Estimation (MLE) as a framework to generate a theory and a functioning set of software to oversee the measurement process and extract the particle size information, while at the same time providing error estimates for those measurements. The theory involved verifying a correct form of the covariance matrix for the noise on the measurement and then estimating particle size parameters using a modified histogram approach.

  5. Characterization of Platelet Concentrates Using Dynamic Light Scattering

    PubMed Central

    Labrie, Audrey; Marshall, Andrea; Bedi, Harjot; Maurer-Spurej, Elisabeth

    2013-01-01

    Summary Background Each year, millions of platelet transfusions save the lives of cancer patients and patients with bleeding complications. However, between 10 and 30% of all platelet transfusions are clinically ineffective as measured by corrected count increments, but no test is currently used to identify and avoid these transfusions. ThromboLUX® is the first platelet test intended to routinely characterize platelet concentrates prior to transfusion. Methods ThromboLUX is a non-invasive, optical test utilizing dynamic light scattering to characterize a platelet sample by the relative quantity of platelets, microparticles, and other particles present in the sample. ThromboLUX also determines the response of platelets to temperature changes. From this information the ThromboLUX score is calculated. Increasing scores indicate increasing numbers of discoid platelets and fewer microparticles. ThromboLUX uses calibrated polystyrene beads as a quality control standard, and accurately measures the size of the beads at multiple temperatures. Results Results from apheresis concentrates showed that ThromboLUX can determine the microparticle content in unmodified samples of platelet concentrates which correlates well with the enumeration by flow cytometry. ThromboLUX detection of microparticles and microaggregates was confirmed by microscopy. Conclusion ThromboLUX provides a comprehensive and novel analysis of platelet samples and has potential as a noninvasive routine test to characterize platelet products to identify and prevent ineffective transfusions. PMID:23652319

  6. Quasi-ballistic light scattering - analytical models versus Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Turcu, Ioan; Kirillin, Mikhail

    2009-08-01

    Approximate analytical solutions for the light scattering in a plan parallel geometry, where each scattering behaves according to a Henyey-Greenstein (HG) phase function, are presented and compared with Monte Carlo simulations. Analyzing each nth order scattered flux, the obtained angular spreading is very well described also by a HG phase function. However, the total scattered flux deviates from the HG type dependence revealing the limits of the approximations.

  7. Micro-focused Brillouin light scattering: imaging spin waves at the nanoscale

    NASA Astrophysics Data System (ADS)

    Sebastian, Thomas; Schultheiss, Katrin; Obry, Björn; Hillebrands, Burkard; Schultheiss, Helmut; Obry, Björn

    2015-06-01

    Spin waves constitute an important part of research in the field of magnetization dynamics. Spin waves are the elementary excitations of the spin system in a magnetically ordered material state and magnons are their quasi particles. In the following article, we will discuss the optical method of Brillouin light scattering (BLS) spectroscopy which is a now a well established tool for the characterization of spin waves. BLS is the inelastic scattering of light from spin waves and confers several benefits: the ability to map the spin wave intensity distribution with spatial resolution and high sensitivity as well as the potential to simultaneously measure the frequency and the wave vector and, therefore, the dispersion properties. For several decades, the field of spin waves gained huge interest by the scientific community due to its relevance regarding fundamental issues of spindynamics in the field of solid states physics. The ongoing research in recent years has put emphasis on the high potential of spin waves regarding information technology. In the emerging field of textit{magnonics}, several concepts for a spin-wave based logic have been proposed and realized. Opposed to charge-based schemes in conventional electronics and spintronics, magnons are charge-free currents of angular momentum, and, therefore, less subject to scattering processes that lead to heating and dissipation. This fact is highlighted by the possibility to utilize spin waves as information carriers in electrically insulating materials. These developments have propelled the quest for ways and mechanisms to guide and manipulate spin-wave transport. In particular, a lot of effort is put into the miniaturization of spin-wave waveguides and the excitation of spin waves in structures with sub-micrometer dimensions. For the further development of potential spin-wave-based devices, the ability to directly observe spin-wave propagation with spatial resolution is crucial. As an optical technique BLS do

  8. High-definition imaging system based on spatial light modulators with light-scattering mode.

    PubMed

    Kikuchi, Hiroshi; Fujii, Takanori; Kawakita, Masahiro; Hirano, Yoshiyuki; Fujikake, Hideo; Sato, Fumio; Takizawa, Kuniharu

    2004-01-01

    We have developed a prototype high-definition imaging system using polymer-dispersed liquid-crystal (PDLC) light valves, which can modulate unpolarized light with high spatial resolution and exhibit a high optical efficiency, based on the light-scattering effect. We fabricated high-definition light valves with a fine polymer-matrix structure in a PDLC film by controlling the curing conditions used during the photopolymerization-induced phase separation and formation process. This device has excellent characteristics, such as a high resolution, with 50 lp/mm for a limiting resolution and greater than 20 lp/mm at the 50% modulation transfer function point, and a reflectivity of greater than 60%. An optically addressable full-color projection display was designed, consisting of three PDLC light valves, a schlieren optical system based on shift-decentralization optics with a xenon lamp illumination and input-image sources with 1.5 million pixels, including electrical image compensation of the gamma characteristics. We succeeded in displaying pictures on a 110-inch screen with a resolution of 810 TV lines and a luminous flux of 1900-2100 American National Standards Institute lumens.

  9. High Pressure Light Scattering Study of Relaxation in the Glass Former Cumene

    NASA Astrophysics Data System (ADS)

    Ransom, Tim; Lyon, Kevin; Oliver, William

    2014-03-01

    To understand relaxation dynamics in glassy systems, a light scattering study on Cumene has been carried out in a diamond anvil cell (DAC) at pressures from 0.2 GPa to 2.5 GPa isothermally at 75 °C. Polarized and depolarized spectra were taken in both near-backscattering and equal-angle 60° forward-scattering geometries at several free spectral ranges from 0.5 GHz to 300 GHz. Depolarized backscattering spectra are converted into susceptibility featuring the evolution of the α-relaxation peak, yielding structural relaxation times τα from 10 ps to 1 ns. We have also developed photon correlation spectroscopy (PCS) in a DAC, giving τα from ~ 1 μs to 1 s. We fit τα over these many decades with a modified VFTH equation τα =τ0 exp[DP/(P0-P)] giving parameters τ0 = 9.2 ps, D = 17.5, and P0 = 4.5 GPa at 75°C. After the α-relaxation peak moves into lower frequencies (P ~ 1 GPa), we observe the emergence of the β-relaxation minimum region. We fit the β-minimum to a power law scaling form χ''(ω) = b(ω/ωmin)a + a(ωmin/ ω)b. Polarized backscattering and forward scattering gives frequency shift ωB and linewidth ΓB values of the longitudinal acoustic modes at two different q. We observe that the usual peak in linewidths does not coincide with ωBτalpha ~ 1, indicating that the longitudinal acoustic modes do not couple with structural relaxation. Tansverse acoustic modes also appear in the depolarized forward scattering spectra. NSF Grant Number: DMR 0552944.

  10. Modulation of Light-Enhancement to Symbiotic Algae by Light-Scattering in Corals and Evolutionary Trends in Bleaching

    PubMed Central

    Marcelino, Luisa A.; Westneat, Mark W.; Stoyneva, Valentina; Henss, Jillian; Rogers, Jeremy D.; Radosevich, Andrew; Turzhitsky, Vladimir; Siple, Margaret; Fang, Andrew; Swain, Timothy D.; Fung, Jennifer; Backman, Vadim

    2013-01-01

    Calcium carbonate skeletons of scleractinian corals amplify light availability to their algal symbionts by diffuse scattering, optimizing photosynthetic energy acquisition. However, the mechanism of scattering and its role in coral evolution and dissolution of algal symbioses during “bleaching” events are largely unknown. Here we show that differences in skeletal fractal architecture at nano/micro-lengthscales within 96 coral taxa result in an 8-fold variation in light-scattering and considerably alter the algal light environment. We identified a continuum of properties that fall between two extremes: (1) corals with low skeletal fractality that are efficient at transporting and redistributing light throughout the colony with low scatter but are at higher risk of bleaching and (2) corals with high skeletal fractality that are inefficient at transporting and redistributing light with high scatter and are at lower risk of bleaching. While levels of excess light derived from the coral skeleton is similar in both groups, the low-scatter corals have a higher rate of light-amplification increase when symbiont concentration is reduced during bleaching, thus creating a positive feedback-loop between symbiont concentration and light-amplification that exposes the remaining symbionts to increasingly higher light intensities. By placing our findings in an evolutionary framework, in conjunction with a novel empirical index of coral bleaching susceptibility, we find significant correlations between bleaching susceptibility and light-scattering despite rich homoplasy in both characters; suggesting that the cost of enhancing light-amplification to the algae is revealed in decreased resilience of the partnership to stress. PMID:23630594

  11. Modulation of light-enhancement to symbiotic algae by light-scattering in corals and evolutionary trends in bleaching.

    PubMed

    Marcelino, Luisa A; Westneat, Mark W; Stoyneva, Valentina; Henss, Jillian; Rogers, Jeremy D; Radosevich, Andrew; Turzhitsky, Vladimir; Siple, Margaret; Fang, Andrew; Swain, Timothy D; Fung, Jennifer; Backman, Vadim

    2013-01-01

    Calcium carbonate skeletons of scleractinian corals amplify light availability to their algal symbionts by diffuse scattering, optimizing photosynthetic energy acquisition. However, the mechanism of scattering and its role in coral evolution and dissolution of algal symbioses during "bleaching" events are largely unknown. Here we show that differences in skeletal fractal architecture at nano/micro-lengthscales within 96 coral taxa result in an 8-fold variation in light-scattering and considerably alter the algal light environment. We identified a continuum of properties that fall between two extremes: (1) corals with low skeletal fractality that are efficient at transporting and redistributing light throughout the colony with low scatter but are at higher risk of bleaching and (2) corals with high skeletal fractality that are inefficient at transporting and redistributing light with high scatter and are at lower risk of bleaching. While levels of excess light derived from the coral skeleton is similar in both groups, the low-scatter corals have a higher rate of light-amplification increase when symbiont concentration is reduced during bleaching, thus creating a positive feedback-loop between symbiont concentration and light-amplification that exposes the remaining symbionts to increasingly higher light intensities. By placing our findings in an evolutionary framework, in conjunction with a novel empirical index of coral bleaching susceptibility, we find significant correlations between bleaching susceptibility and light-scattering despite rich homoplasy in both characters; suggesting that the cost of enhancing light-amplification to the algae is revealed in decreased resilience of the partnership to stress.

  12. Meson spectroscopy, resonances and scattering on the lattice

    NASA Astrophysics Data System (ADS)

    Thomas, Christopher E.

    2017-03-01

    I discuss some recent progress in studying the spectra of mesons using first-principles lattice QCD calculations. In particular, I highlight some new results on resonances, near-threshold states and related scattering phenomena - this is an area which is very interesting experimentally and theoretically and where we have made significant advances in the last few years. I conclude with an outlook on future prospects.

  13. Blending Bragg scattering with optical absorption: spectroscopy without a spectroscope

    NASA Astrophysics Data System (ADS)

    Nozières, Philippe

    2006-03-01

    A double resonance method is proposed, blending resonant X-ray Bragg scattering with an optical laser that blurs the Bragg spots. One can detect the cross signal without resolving the satellite lines from the main beam, simply modulating the laser intensity at low frequency and carrying a synchronous detection. The concept is illustrated on two simple naive examples. To cite this article: Ph. Nozières, C. R. Physique 7 (2006).

  14. LIGHT BEAMS: Peculiarities of propagation of quasi-diffraction-free light beams in strongly scattering absorbing media

    NASA Astrophysics Data System (ADS)

    Katsev, I. L.; Prikhach, A. S.; Kazak, N. S.; Kroening, M.

    2006-04-01

    Based on the relation between the theory of light field coherence and theory of radiation transfer in scattering media, a method is proposed for calculating the illumination distribution produced by coherent quasi-diffraction-free beams at different penetration depths of radiation into scattering media such as biological tissues. The method uses the optical transfer function or the point spread function (PSF) of the medium. A simple and convenient analytic PSF model is described. Examples of the illumination distribution produced by a Bessel light beam in a medium with optical parameters typical of real biological tissues are presented. It is shown that the half-width of the axial maximum of a Bessel light beam scattered due to scattering almost does not increase up to optical depths where the contribution of multiple scattering is already considerable.

  15. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Benedetto, Antonio; Kearley, Gordon J.

    2016-10-01

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics.

  16. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering.

    PubMed

    Benedetto, Antonio; Kearley, Gordon J

    2016-10-05

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics.

  17. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering

    PubMed Central

    Benedetto, Antonio; Kearley, Gordon J.

    2016-01-01

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics. PMID:27703184

  18. Nature of light scattering in dental enamel and dentin at visible and near-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Glena, Richard E.; Featherstone, John D. B.; Seka, Wolf

    1995-03-01

    The light-scattering properties of dental enamel and dentin were measured at 543, 632, and 1053 nm. Angularly resolved scattering distributions for these materials were measured from 0 deg to 180 deg using a rotating goniometer. Surface scattering was minimized by immersing the samples in an index-matching bath. The scattering and absorption coefficients and the scattering phase function were deduced by comparing the measured scattering data with angularly resolved Monte Carlo light-scattering simulations. Enamel and dentin were best represented by a linear combination of a highly forward-peaked Henyey-Greenstein (HG) phase function and an isotropic phase function. Enamel weakly scatters light between 543 nm and 1.06 mu m, with the scattering coefficient ( mu s) ranging from mu s = 15 to 105 cm-1. The phase function is a combination of a HG function with g = 0.96 and a 30-60% isotropic phase function. For enamel, absorption is negligible. Dentin scatters strongly in the visible and near IR ( mu s approximately equals 260 cm-1) and absorbs weakly ( mu a approximately equals 4 cm-1). The scattering phase function for dentin is described by a HG function with g = 0.93 and a very weak isotropic scattering component ( approximately 2%).

  19. Light scattering and cell volumes in osmotically stressed and frozen-thawed cells.

    PubMed

    McGann, L E; Walterson, M L; Hogg, L M

    1988-01-01

    Recent reports, indicating that under some conditions the intensity of light scattering from cells is a nonlinear function of cell volume, have led to the widespread generalization that intensity of low-angle light scattering indicates cell size. This study was performed to measure the relationships between light scattering and cell volumes in an-isotonic solutions and after a freeze-thaw stress. Cell volumes in isolated human lymphocytes, human granulocytes, and hamster fibroblasts were deliberately altered by exposure to anisotonic solutions. Boyle-vant Hoff plots of cell volume as a function of inverse osmotic pressure showed that the cells behaved as osmometers. Similar plots of right-angle and low-angle light scattering showed that the intensity of light scattering varied inversely with cell volume. In other experiments where cells were frozen without cryoprotectant at various sub zero temperatures to -25 degrees C and then thawed rapidly, cell viability decreased progressively with decreasing temperature, as did the intensity of both low-angle and right-angle light scattering, although cell volumes remained relatively constant. The intensity of both low- and high-angle light scattering varied inversely with cell volumes in hypertonic and hypotonic solutions, but cell damage induced by freezing and thawing resulted in significant reductions in the intensity of low-angle light scattering with little change in cell volume. These observations show that light scattering and cell volumes can vary independently, and they underline the need for a better understanding of the phenomenon of light scattering from living cells.

  20. Analysis of light propagation in highly scattering media by path-length-assigned Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Ishii, Katsuhiro; Nishidate, Izumi; Iwai, Toshiaki

    2014-05-01

    Numerical analysis of optical propagation in highly scattering media is investigated when light is normally incident to the surface and re-emerges backward from the same point. This situation corresponds to practical light scattering setups, such as in optical coherence tomography. The simulation uses the path-length-assigned Monte Carlo method based on an ellipsoidal algorithm. The spatial distribution of the scattered light is determined and the dependence of its width and penetration depth on the path-length is found. The backscattered light is classified into three types, in which ballistic, snake, and diffuse photons are dominant.

  1. Light-scattering polarization measurements as a new parameter in flow cytometry

    SciTech Connect

    de Grooth, B.G.; Terstappen, L.W.; Puppels, G.J.; Greve, J.

    1987-11-01

    Polarization measurement of orthogonal light scattering is introduced as a new optical parameter in flow cytometry. In the experimental setup, the electrical field of the incident laser beam is polarized in the direction of the sample flow. The intensity of the orthogonal light scattering polarized along the direction of the incoming laser beam is called depolarized orthogonal light scattering. Theoretical analysis shows that for small values of the detection aperture, the measured depolarization is caused by anisotropic cell structures and multiple scattering processes inside the cell. Measurements of the orthogonal depolarized light scattering in combination with the normal orthogonal light scattering of human leucocytes revealed two populations of granulocytes. By means of cell sorting it was shown that the granulocytes with a relatively high depolarization are eosinophilic granulocytes. Similar experiments with human lymphocytes revealed a minor subpopulation of yet-unidentified lymphocytes with a relative large orthogonal light-scattering depolarization. The results were obtained with an argon ion laser tuned at different wavelengths as well as with a 630-nm helium neon laser. These results show that measurement of depolarized orthogonal light scattering is a useful new parameter for flow-cytometric cell differentiation.

  2. Form fluctuations of polymer loaded spherical microemulsions studied by neutron scattering and dielectric spectroscopy

    NASA Astrophysics Data System (ADS)

    Kuttich, B.; Falus, P.; Grillo, I.; Stühn, B.

    2014-08-01

    We investigate the structure and shell dynamics of the droplet phase in water/AOT/octane microemulsions with polyethyleneglycol (MW = 1500) molecules loaded in the droplets. Size and polydispersity of the droplets is determined with small angle X-ray scattering and small angle neutron scattering experiments. Shell fluctuations are measured with neutron spin echo spectroscopy and related to the dynamic percolation seen in dielectric spectroscopy. Shell fluctuations are found to be well described by the bending modulus of the shell and the viscosities inside and outside the droplets. Addition of the polymer decreases the modulus for small droplets. For large droplets the opposite is found as percolation temperature shifts to higher values.

  3. Light scattering from human corneal grafts: Bulk and surface contribution

    NASA Astrophysics Data System (ADS)

    Latour, Gaël; Georges, Gaëlle; Lamoine, Laure Siozade; Deumié, Carole; Conrath, John; Hoffart, Louis

    2010-09-01

    The cornea is the only transparent tissue in the body. The transparency is the main characteristic of the corneal tissue, and depends not only on the transmission coefficient but also on the losses by scattering and absorption. The scattering properties of the cornea tissues become one of the most important parameters in the case of the corneal graft. These scattering properties are studied in this paper in the reflected half area, similar to the diagnosis configuration. We quantify the influence of the cornea thickness and of the epithelial layer on scattering level. The technique of ellipsometry on scattered field is also used to analyze the polarization properties in order to determine the origin of scattering (surface and/or bulk).

  4. Experimental demonstration and modeling of the internal light scattering profile within solar cells due to random dielectric scatterers

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Munday, Jeremy N.

    2016-01-01

    Many photovoltaic technologies are shifting toward thin-film devices to simultaneously reduce costs and improve carrier collection efficiencies; however, the need for nearly complete light absorption within the semiconductor to achieve large short-circuit currents constrains this thickness reduction. Light trapping strategies can be employed to increase absorption in thinner devices. Random scattering coatings offer a simple, cost-effective way to increase solar cell absorption without the drawback of increased surface recombination or reduced bandwidth that occurs when using surface texturing or gratings. However, coatings that show excellent performance as scatterers in free space generally do not enhance device absorption as much as an ideal Lambertian scatterer. Here, we present an experimental technique and theoretical model that accurately describes the absorption improvement that is achievable with coatings based on random ensembles of dielectric scatterers. We find that the ideal Lambertian model substantially overestimates the experimental scattering results, but significant path length enhancements are still achievable. The experimental techniques presented here should enable the testing of various optical models that attempt to surpass the ray optics light trapping limit, which have in many cases been hindered by the experimental difficulty of coupling the incident light into the optical modes of the absorber.

  5. Polarized light imaging specifies the anisotropy of light scattering in the superficial layer of a tissue

    NASA Astrophysics Data System (ADS)

    Jacques, Steven L.; Roussel, Stéphane; Samatham, Ravikant

    2016-07-01

    This report describes how optical images acquired using linearly polarized light can specify the anisotropy of scattering (g) and the ratio of reduced scattering [μs‧=μs(1-g)] to absorption (μa), i.e., N‧=μs‧/μa. A camera acquired copolarized (HH) and crosspolarized (HV) reflectance images of a tissue (skin), which yielded images based on the intensity (I=HH+HV) and difference (Q=HH-HV) of reflectance images. Monte Carlo simulations generated an analysis grid (or lookup table), which mapped Q and I into a grid of g versus N‧, i.e., g(Q,I) and N‧(Q,I). The anisotropy g is interesting because it is sensitive to the submicrometer structure of biological tissues. Hence, polarized light imaging can monitor shifts in the submicrometer (50 to 1000 nm) structure of tissues. The Q values for forearm skin on two subjects (one Caucasian, one pigmented) were in the range of 0.046±0.007 (24), which is the mean±SD for 24 measurements on 8 skin sites×3 visible wavelengths, 470, 524, and 625 nm, which indicated g values of 0.67±0.07 (24).

  6. Simulation of light scattering by a pressure deformed red blood cell with a parallel FDTD method

    NASA Astrophysics Data System (ADS)

    Brock, Robert S.; Hu, Xin-Hua; Yang, Ping; Lu, Jun Q.

    2005-03-01

    Mature human red blood cells (RBCs) are light scatterers with homogeneous bodies enclosed by membranes and have attracted significant attention for optical diagnosis of disorders related to blood. RBCs possess viscoelastic structures and tend to deform from biconcave shapes isovolumetrically in blood flow in response to pressure variations. Elastic scattering of light by a deformed RBC provides a means to determine their shapes because of the presence of strong light scattering signals, and development of efficient modeling tools is important for developing bed-side instrumentation. The size parameters α, defined as α=2πα/λ with 2α as the characteristic size of the scatterer and λ as the light wavelength in the host medium, of the scatterer of RBCs are in the range of 10 to 50 for wavelengths of light in visible and near-infrared regions, and no analytical solutions have been reported for light scattering from deformed RBCs. We developed a parallel Finite-Difference-Time-Domain (FDTD) method to numerically simulate light scattering by a deformed RBC in a carrier fluid under different flow pressures. The use of parallel computing techniques significantly reduced the computation time of the FDTD method on a low-cost PC cluster. The deformed RBC is modeled in the 3D space as a homogeneous body characterized by a complex dielectric constant at the given wavelength of the incident light. The angular distribution of the light scattering signal was obtained in the form of the Mueller scattering matrix elements and their dependence on shape change due to pressure variation and orientation was studied. Also calculated were the scattering and absorption efficiencies and the potential for using these results to probe the shape change of RBCs will be discussed.

  7. NEUTRON SPECTROSCOPY BY DOUBLE SCATTER AND ASSOCIATED PARTICLE TECHNIQUES.

    SciTech Connect

    DIOSZEGI,I.

    2007-10-28

    Multiple detectors can provide [1,2] both directional and spectroscopic information. Neutron spectra may be obtained by neutron double scatter (DSNS), or the spontaneous fission associated particle (AP) technique. Spontaneous fission results in the creation of fission fragments and the release of gamma rays and neutrons. As these occur at the same instant, they are correlated in time. Thus gamma ray detection can start a timing sequence relative to a neutron detector where the time difference is dominated by neutron time-of-flight. In this paper we describe these techniques and compare experimental results with Monte Carlo calculations.

  8. Ultraslow-light effects in symmetric and asymmetric waveguide structures with moon-like scatterers

    NASA Astrophysics Data System (ADS)

    Wan, Yong; Ge, Xiao-Hui; Xu, Sheng; Guo, Yue; Yuan, Feng

    2017-02-01

    Ultraslow-light effects in two-dimensional hexagonal-lattice coupled waveguide with moon-like scatterers were theoretically studied using the plane-wave expansion method. For symmetric structures, simulations showed that slow light with high group index can be achieved by shifting the scatterers and adjusting the radius of moon-like scatterers. The maximum group index was over 8:0 × 104. For asymmetric structures, simulations showed that slow light with flat band and high group index can be obtained by shifting the scatterers, adjusting the radius of moon-like scatterers, and rotating the scatterers. The maximum group index was over 5:7 × 105 with a "saddle-like" relationship between the frequency and group index.

  9. Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment from lattice QCD.

    PubMed

    Blum, Thomas; Chowdhury, Saumitra; Hayakawa, Masashi; Izubuchi, Taku

    2015-01-09

    The most compelling possibility for a new law of nature beyond the four fundamental forces comprising the standard model of high-energy physics is the discrepancy between measurements and calculations of the muon anomalous magnetic moment. Until now a key part of the calculation, the hadronic light-by-light contribution, has only been accessible from models of QCD, the quantum description of the strong force, whose accuracy at the required level may be questioned. A first principles calculation with systematically improvable errors is needed, along with the upcoming experiments, to decisively settle the matter. For the first time, the form factor that yields the light-by-light scattering contribution to the muon anomalous magnetic moment is computed in such a framework, lattice QCD+QED and QED. A nonperturbative treatment of QED is used and checked against perturbation theory. The hadronic contribution is calculated for unphysical quark and muon masses, and only the diagram with a single quark loop is computed for which statistically significant signals are obtained. Initial results are promising, and the prospect for a complete calculation with physical masses and controlled errors is discussed.

  10. Hadronic Light-by-Light Scattering Contribution to the Muon Anomalous Magnetic Moment from Lattice QCD

    NASA Astrophysics Data System (ADS)

    Blum, Thomas; Chowdhury, Saumitra; Hayakawa, Masashi; Izubuchi, Taku

    2015-01-01

    The most compelling possibility for a new law of nature beyond the four fundamental forces comprising the standard model of high-energy physics is the discrepancy between measurements and calculations of the muon anomalous magnetic moment. Until now a key part of the calculation, the hadronic light-by-light contribution, has only been accessible from models of QCD, the quantum description of the strong force, whose accuracy at the required level may be questioned. A first principles calculation with systematically improvable errors is needed, along with the upcoming experiments, to decisively settle the matter. For the first time, the form factor that yields the light-by-light scattering contribution to the muon anomalous magnetic moment is computed in such a framework, lattice QCD +QED and QED. A nonperturbative treatment of QED is used and checked against perturbation theory. The hadronic contribution is calculated for unphysical quark and muon masses, and only the diagram with a single quark loop is computed for which statistically significant signals are obtained. Initial results are promising, and the prospect for a complete calculation with physical masses and controlled errors is discussed.

  11. Literature survey for suppression of scattered light in large space telescopes

    NASA Technical Reports Server (NTRS)

    Tifft, W. G.; Fannin, B. B.

    1973-01-01

    A literature survey is presented of articles dealing with all aspects of predicting, measuring, and controlling unwanted scattered (stray) light. The survey is divided into four broad classifications: (1) existing baffle/telescope designs; (2) computer programs for the analysis/design of light suppression systems; (3) the mechanism, measurement, and control of light scattering; and (4) the advantages and problems introduced by the space environment for the operation of diffraction-limited optical systems.

  12. Dynamic light-scattering measurement comparability of nanomaterial suspensions

    NASA Astrophysics Data System (ADS)

    Nickel, Carmen; Angelstorf, Judith; Bienert, Ralf; Burkart, Corinna; Gabsch, Stephan; Giebner, Sabrina; Haase, Andrea; Hellack, Bryan; Hollert, Henner; Hund-Rinke, Kerstin; Jungmann, Dirk; Kaminski, Heinz; Luch, Andreas; Maes, Hanna M.; Nogowski, André; Oetken, Matthias; Schaeffer, Andreas; Schiwy, Andreas; Schlich, Karsten; Stintz, Michael; von der Kammer, Frank; Kuhlbusch, Thomas A. J.

    2014-02-01

    Increased use of nanomaterials in everyday products leads to their environmental release and therefore, the information need on their fate and behaviour. Nanomaterials have to be suspended with high repeatability and comparability for studies on environmental effects. They also have to be well characterised with a focus on the state of agglomeration and particle size distribution. Dynamic light-scattering (DLS) is a common technique used for these measurements. If suspensions are prepared in different laboratories, then concern has risen about the comparability of the measured results, especially when different DLS instruments are used. Therefore, for quality assurance, a round-robin test was conducted to assess the comparability of different DLS instruments and a dispersion protocol in ten independent laboratories. Polystyrene and TiO2 were chosen as test (nano)materials. For the comparability of the DLS instruments, the average sizes of the PSL and a stabilised TiO2 suspension were measured. The measured average hydrodynamic diameter shows an overall good inter-laboratory comparability. For the PSL suspension, an average hydrodynamic diameter of 201 ± 13 nm and for the TiO2 suspension an average diameter of 224 ± 24 nm were detected. For the TiO2 suspension that was prepared at each laboratory following an established suspension preparation protocol, an average hydrodynamic diameter of 211 ± 11 nm was detected. The measured average particle size (mode) increased up to 284 nm with a high standard deviation of 119 nm if the preparation protocol could not established and different procedures or different equipment were employed. This study shows that no significant differences between the employed DLS instrument types were determined. It was also shown that comparable measurements and suspension preparation could be achieved if well-defined suspension preparation protocols and comparable equipment can be used.

  13. Dynamic Light Scattering Based Microelectrophoresis: Main Prospects and Limitations

    PubMed Central

    Uskoković, Vuk

    2013-01-01

    Microelectrophoresis based on the dynamic light scattering (DLS) effect has been a major tool for assessing and controlling the conditions for stability of colloidal systems. However, both the DLS methods for characterization of the hydrodynamic size of dispersed submicron particles and the theory behind the electrokinetic phenomena are associated with fundamental and practical approximations that limit their sensitivity and information output. Some of these fundamental limitations, including the spherical approximation of DLS measurements and an inability of microelectrophoretic analyses of colloidal systems to detect discrete charges and differ between differently charged particle surfaces due to rotational diffusion and particle orientation averaging, are revisited in this work. Along with that, the main prospects of these two analytical methods are mentioned. A detailed review of the role of zeta potential in processes of biochemical nature is given too. It is argued that although zeta potential has been used as one of the main parameters in controlling the stability of colloidal dispersions, its application potentials are much broader. Manipulating surface charges of interacting species in designing complex soft matter morphologies using the concept of zeta potential, intensively investigated recently, is given as one of the examples. Branching out from the field of colloid chemistry, DLS and zeta potential analyses are now increasingly finding application in drug delivery, biotechnologies, physical chemistry of nanoscale phenomena and other research fields that stand on the frontier of the contemporary science. Coupling the DLS-based microelectrophoretic systems with complementary characterization methods is mentioned as one of the prosperous paths for increasing the information output of these two analytical techniques. PMID:23904690

  14. Peculiarities of propagation of quasi-diffraction-free light beams in strongly scattering absorbing media

    SciTech Connect

    Katsev, I L; Prikhach, A S; Kazak, N S; Kroening, M

    2006-04-30

    Based on the relation between the theory of light field coherence and theory of radiation transfer in scattering media, a method is proposed for calculating the illumination distribution produced by coherent quasi-diffraction-free beams at different penetration depths of radiation into scattering media such as biological tissues. The method uses the optical transfer function or the point spread function (PSF) of the medium. A simple and convenient analytic PSF model is described. Examples of the illumination distribution produced by a Bessel light beam in a medium with optical parameters typical of real biological tissues are presented. It is shown that the half-width of the axial maximum of a Bessel light beam scattered due to scattering almost does not increase up to optical depths where the contribution of multiple scattering is already considerable. (light beams)

  15. Measuring the dynamics of structural changes in biological macromolecules from light scattering data

    NASA Technical Reports Server (NTRS)

    Johnson, Adriel D.

    1993-01-01

    Examining techniques to study the dynamics of structural changes in various molecules has been an ongoing goal of the space program. Knowing how these phenomena occur in biological systems is fundamental to understanding what is necessary for life to remain functional in the space environment. A hierarchy of biological organization is functionally described when cells join together small organic molecules to form larger and more complex molecules. Characterizing the architecture of a particular macromolecule helps determine how that molecule works in the living cell and is basic to the diversity of life. Understanding this arrangement involves the correlation of the structure of macromolecules with their functions. A light scattering photometer was developed for detecting continuous measurement of the angular spectrum of light scattered by dynamically changing systems. The analysis of light scattered by biological macromolecules can be used to determine concentration, size, shape, molecular weight, and structural changes of cells, such as erythrocytes. Some light scattering photometers can collect and store 120 angular scattering spectra per minute, with an angular resolution of 0.2 deg which can be displayed with computer graphics. The light scattering photometer does the following: functions to produce and detect scattered light; determines scatter angles; and collects, stores, and analyzes data.

  16. Studying complex fluids and crystal formation using Dynamic Light Scattering and Optical Probe Diffusion

    NASA Astrophysics Data System (ADS)

    Streletzky, Kiril A.

    2004-10-01

    Dynamic light scattering (DLS) spectroscopy provides non-destructive analytic technique for probing structure and dynamics of polymer solutions, colloids, micellar systems, liquid crystals, and, in some cases, observation of nucleation and crystal growth. The method of optical probe diffusion uses DLS to measure transport of dilute mesoscopic probes in a complex fluid solution. If tracer particles are the dominant scatterers in solution, their diffusion provides important information for inferring physical properties of the complex fluid. In situ nature of DLS allows non-invasive studies of different chemical and physical processes such as polymer and colloidal diffusion, gelation, micellar aggregation and dynamics. DLS is also useful for studying critical behavior of liquid crystals and for observing crystallization from clear solutions. The highlights of our results obtained using DLS and optical probe diffusion are presented. These examples include: a) research on polymer dynamics in dilute and concentrated solutions of a neutral HPC polymer; b) project on aggregation and transport of spherical Tx-100 micelles; c) study of crystallization of molecular sieve zeolite NaA.

  17. Light scattering by radially inhomogeneous fuel droplets in a high-temperature environment

    NASA Astrophysics Data System (ADS)

    Schneider, Michael; Hirleman, E. Dan; Saleheen, Hasan I.; Chowdhury, Dipakbin Q.; Hill, Steven C.

    1993-05-01

    Light scattering by radially inhomogeneous fuel droplets has been calculated using both geometrical optics (GO) and the exact separation of variables (SV) solutions. The refractive index profiles of the fuel droplets were those calculated by Kneer et al. The GO and SV solutions agree very well in the forward direction (for scattering angles between 30 and 60 degrees), and less well in the backward direction (for scattering angles between 140 and 170 degrees). Both amplitudes and phases of the scattered light are compared. The agreement in the backward direction is much better for 40 micrometers diameter droplets than for 20 micrometers diameter droplets.

  18. New scheme of the Discrete Sources Method for light scattering analysis of a particle breaking interface

    NASA Astrophysics Data System (ADS)

    Eremin, Yuri; Wriedt, Thomas

    2014-12-01

    The Discrete Sources Method (DSM) has been modified to analyze polarized light scattering by an axial symmetric penetrable nanoparticle partially embedded into a substrate. The new numerical scheme of the DSM enables to consider scattering from such substrate defects as flat particles, mounds, pits and voids. A detailed description of the numerical scheme is provided. The developed computer model has been employed to investigate scattering from a shallow particle and pit. Simulation results corresponding to the Differential Scattering Cross-Section and the integral response for P/S polarized light are presented.

  19. Light scattering by irregular particles much larger than the wavelength with wavelength-scale surface roughness.

    PubMed

    Grynko, Yevgen; Shkuratov, Yuriy; Förstner, Jens

    2016-08-01

    We simulate light scattering by random irregular particles that have dimensions much larger than the wavelength of incident light at the size parameter of X=200 using the discontinuous Galerkin time domain method. A comparison of the DGTD solution for smoothly faceted particles with that obtained with a geometric optics model shows good agreement for the scattering angle curves of intensity and polarization. If a wavelength-scale surface roughness is introduced, diffuse scattering at rough interface results in smooth and featureless curves for all scattering matrix elements which is consistent with the laboratory measurements of real samples.

  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. Coherent backscattering of light with nonlinear atomic scatterers

    SciTech Connect

    Wellens, T.; Gremaud, B.; Delande, D.; Miniatura, C.

    2006-01-15

    We study coherent backscattering of a monochromatic laser by a dilute gas of cold two-level atoms in the weakly nonlinear regime. The nonlinear response of the atoms results in a modification of both the average field propagation (nonlinear refractive index) and the scattering events. Using a perturbative approach, the nonlinear effects arise from inelastic two-photon scattering processes. We present a detailed diagrammatic derivation of the elastic and inelastic components of the backscattering signal for both scalar and vectorial photons. In particular, we show that the coherent backscattering phenomenon originates in some cases from the interference between three different scattering amplitudes. This is in marked contrast with the linear regime where it is due to the interference between two different scattering amplitudes. In particular we show that, if elastically scattered photons are filtered out from the photodetection signal, the nonlinear backscattering enhancement factor exceeds the linear barrier of 2, consistently with a three-amplitude interference effect.

  2. Influence of surface light scattering in hydrophobic acrylic intraocular lenses on laser beam transmittance.

    PubMed

    Shiraya, Tomoyasu; Kato, Satoshi; Minami, Keiichiro; Miyata, Kazunori

    2017-02-01

    The aim of this study was to experimentally examine the changes in the transmittances of photocoagulation lasers when surface light scattering increases in AcrySof intraocular lenses (IOLs). SA60AT IOLs (Alcon) were acceleratingly aging for 0, 3, 5, and 10 years to simulate surface light scattering, and the surface light-scattering intensities of both IOL surfaces were measured using a Scheimpflug photographer. The powers of laser beams that passed from a laser photocoagulator through the aged IOLs were measured at 532, 577, and 647 nm. Changes in the laser power and transmittance with the years of aging and the intensities of surface light scattering were examined. Although the intensity of surface light scattering increased with the years of aging, the laser power did not change with the years of aging (P > 0.30, Kruskal-Wallis test). There were no significant changes in the laser transmittance with the years of aging or the laser wavelength (P > 0.30 and 0.57, respectively). The intensity of surface light scattering revealed no significant association with the laser transmittance at any wavelength (P > 0.37, liner regression). The increases in the surface light scattering of the AcrySof IOLs would not influence retinal photocoagulation treatments for up to 10 years after implantation.

  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. Single and multiple light scattering studies of PDLC films in the presence of electric fields

    NASA Astrophysics Data System (ADS)

    Wu, Wei

    Light scattering from Polymer Dispersed Liquid Crystal (PDLC) films is studied in four major respects: the differential scattering cross-section of a single liquid crystal droplet; the total scattering cross-section and film transmittance; multiple scattering effects; and scattering by absorbing droplets (PDLC doped with dichroic dye). The effects of applied electric field, light wavelength and the liquid crystal droplet size on the scattering behavior are examined. PDLC scattering properties under electric field are described by combining the Anomalous Diffraction Approach (ADA) with PDLC electro-optical response theory. Numerical computation results directly demonstrate how the total scattering cross section relates to the incident light wavelength, the droplet size and the applied electric field. Transmittance measurements are used to study the total scattering cross-section. Analyses of the transmittance characteristics show good agreement with the theoretical predictions. PDLC samples with a practical contrast ratio exhibit strong multiple scattering effects. Studies of the single scattering differential cross section provide a foundation for the modeling and experimental work on the multiple scattering effects. Single scattering characteristics of a bipolar droplet director configuration are derived for a highly symmetric situation. The results offer qualitative explanations for some experimental observations, such as the presence of off-normal maxima and breakdown of rotational symmetry in the scattering pattern. As a novel approach, we propose a multiple scattering model for PDLC based on successive order and Monte Carlo methods. This model, along with ADA and electro-optical response theories, was used to calculate the angular distribution of scattered light and electric field switching response. The predictions demonstrate close quantitative agreement with experimental results. Incorporating complex refractive indices to treat dye- doped PDLC

  5. Development of wide-angle 2D light scattering static cytometry

    NASA Astrophysics Data System (ADS)

    Xie, Linyan; Liu, Qiao; Shao, Changshun; Su, Xuantao

    2016-10-01

    We have recently developed a 2D light scattering static cytometer for cellular analysis in a label-free manner, which measures side scatter (SSC) light in the polar angular range from 79 to 101 degrees. Compared with conventional flow cytometry, our cytometric technique requires no fluorescent labeling of the cells, and static cytometry measurements can be performed without flow control. In this paper we present an improved label-free static cytometer that can obtain 2D light scattering patterns in a wider angular range. By illuminating the static microspheres on chip with a scanning optical fiber, wide-angle 2D light scattering patterns of single standard microspheres with a mean diameter of 3.87 μm are obtained. The 2D patterns of 3.87 μm microspheres contain both large-angle forward scatter (FSC) and SSC light in the polar angular range from 40 to 100 degrees, approximately. Experimental 2D patterns of 3.87 μm microspheres are in good agreement with Mie theory simulated ones. The wide-angle light scattering measurements may provide a better resolution for particle analysis as compared with the SSC measurements. Two dimensional light scattering patterns of HL-60 human acute leukemia cells are obtained by using our static cytometer. Compared with SSC 2D light scattering patterns, wide-angle 2D patterns contain richer information of the HL-60 cells. The obtaining of 2D light scattering patterns in a wide angular range could help to enhance the capabilities of our label-free static cytometry for cell analysis.

  6. Localized dynamic light scattering: a new approach to dynamic measurements in optical microscopy.

    PubMed

    Meller, A; Bar-Ziv, R; Tlusty, T; Moses, E; Stavans, J; Safran, S A

    1998-03-01

    We present a new approach to probing single-particle dynamics that uses dynamic light scattering from a localized region. By scattering a focused laser beam from a micron-size particle, we measure its spatial fluctuations via the temporal autocorrelation of the scattered intensity. We demonstrate the applicability of this approach by measuring the three-dimensional force constants of a single bead and a pair of beads trapped by laser tweezers. The scattering equations that relate the scattered intensity autocorrelation to the particle position correlation function are derived. This technique has potential applications for measurement of biomolecular force constants and probing viscoelastic properties of complex media.

  7. Stimulated Light Emission and Inelastic Scattering by a Classical Linear System of Rotating Particles

    SciTech Connect

    Asenjo-Garcia, Ana; Manjavacas, Alejandro; Garcia de Abajo, F. Javier

    2011-05-27

    The rotational dynamics of particles subject to external illumination is found to produce light amplification and inelastic scattering at high rotation velocities. Light emission at frequencies shifted with respect to the incident light by twice the rotation frequency dominates over elastic scattering within a wide range of light and rotation frequencies. Remarkably, net amplification of the incident light is produced in this classical linear system via stimulated emission. Large optically induced acceleration rates are predicted in vacuum accompanied by moderate heating of the particle, thus supporting the possibility of observing these effects under extreme rotation conditions.

  8. X-ray Photoelectron Spectroscopy (XPS), Rutherford Back Scattering (RBS) studies

    NASA Technical Reports Server (NTRS)

    Neely, W. C.; Bozak, M. J.; Williams, J. R.

    1993-01-01

    X-ray photoelectron spectroscopy (XPS), Rutherford Back Scattering (RBS) studies of each of sample received were completed. Since low angle X-ray could not be performed because of instrumentation problems, Auger spectrometry was employed instead. The results of these measurements for each of the samples is discussed in turn.

  9. Data fusion of visible/near-infrared spectroscopy and spectral scattering for apple quality assessment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Visible/near-infrared (VNIR) spectroscopy and spectral scattering are based on different sensing principles, and they have shown different abilities for predicting apple fruit firmness and soluble solids content (SSC). Hence the two techniques could work synergistically to improve the quality predic...

  10. Absorption and Scattering Coefficients: A Biophysical-Chemistry Experiment Using Reflectance Spectroscopy

    ERIC Educational Resources Information Center

    Cordon, Gabriela B.; Lagorio, M. Gabriela

    2007-01-01

    A biophysical-chemistry experiment, based on the reflectance spectroscopy for calculating the absorption and scattering coefficients of leaves is described. The results show that different plants species exhibit different values for both the coefficients because of their different pigment composition.

  11. Broadband coherent anti-Stokes Raman scattering spectroscopy in supercontinuum optical trap

    NASA Astrophysics Data System (ADS)

    Shi, Kebin; Li, Peng; Liu, Zhiwen

    2007-04-01

    The authors report on a supercontinuum tweezer which combines tweezing with broadband (˜3000cm-1) coherent anti-Stokes Raman scattering (CARS) spectroscopy by taking advantage of the high spatial coherence and broad bandwidth of pulsed supercontinuum generated in a nonlinear photonic crystal fiber. Polarization-discriminated and time-resolved CARS is investigated to suppress the nonresonant four-wave-mixing background.

  12. Asymmetrical flow field-flow fractionation with multi-angle light scattering and quasi-elastic light scattering for characterization of polymersomes: comparison with classical techniques.

    PubMed

    Till, Ugo; Gaucher-Delmas, Mireille; Saint-Aguet, Pascale; Hamon, Glenn; Marty, Jean-Daniel; Chassenieux, Christophe; Payré, Bruno; Goudounèche, Dominique; Mingotaud, Anne-Françoise; Violleau, Frédéric

    2014-12-01

    Polymersomes formed from amphiphilic block copolymers, such as poly(ethyleneoxide-b-ε-caprolactone) (PEO-b-PCL) or poly(ethyleneoxide-b-methylmethacrylate), were characterized by asymmetrical flow field-flow fractionation coupled with quasi-elastic light scattering (QELS), multi-angle light scattering (MALS), and refractive index detection, leading to the determination of their size, shape, and molecular weight. The method was cross-examined with more classical ones, like batch dynamic and static light scattering, electron microscopy, and atomic force microscopy. The results show good complementarities between all the techniques; asymmetrical flow field-flow fractionation being the most pertinent one when the sample exhibits several different types of population.

  13. 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

  14. Retinal image degradation by optical aberrations and light scatter in normal and albino chick eyes

    NASA Astrophysics Data System (ADS)

    Tian, Yibin; Shieh, Kevin; Wildsoet, Christine F.

    2007-02-01

    Comprehensive evaluation of retinal image quality requires that light scatter as well as optical aberrations be considered. In investigating how retinal image degradation affects eye growth in the chick model of myopia, we developed a simple method based on Shack-Hartmann images for evaluating the effects of both monochromatic aberrations and light scatter on retinal image quality. We further evaluated our method in the current study by applying it to data collected from both normal chick eyes and albino eyes that were expected to show increased intraocular light scatter. To analyze light scatter in our method, each Shack-Hartmann dot is treated as a local point spread function (PSF) that is the convolution of a local scatter PSF and a lenslet diffraction PSF. The local scatter PSF is obtained by de-convolution, and is fitted with a circularly symmetric Gaussian function using nonlinear regressions. A whole-eye scatter PSF also can be derived from the local scatter PSFs for the analyzed pupil. Aberrations are analyzed using OSA standard Zernike polynomials, and aberration-related PSF calculated from reconstructed wavefront using fast Fourier transform. Modulation transfer functions (MTFs) are computed separately for aberration and scatter PSFs, and a whole-eye MTF is derived as the product of the two. This method was applied to 4 normal and 4 albino eyes. Compared to normal eyes, albino eyes were more aberrated and showed greater light scatter. As a result, overall retinal image degradation was much greater in albino eyes than in normal eyes, with the relative contribution to retinal image degradation of light scatter compared to aberrations also being greater for albino eyes.

  15. 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

  16. Influence of Forward and Multiple Light Scatter on the Measurement of Beam Attenuation in Highly Scattering Marine Environments

    NASA Astrophysics Data System (ADS)

    Piskozub, Jacek; Stramski, Dariusz; Terrill, Eric; Melville, W. Kendall

    2004-08-01

    Using three-dimensional Monte Carlo radiative transfer simulations, we examine the effect of beam transmissometer geometry on the relative error in the measurement of the beam-attenuation coefficient in an aquatic environment characterized by intense light scattering, especially within submerged bubble clouds entrained by surface-wave breaking. We discuss the forward-scattering error associated with the detection of photons scattered at small angles (< 1°) and the multiple-scattering error associated with the detection of photons scattered more than once along the path length of the instrument. Several scattering phase functions describing bubble clouds at different bubble void fractions in the water are considered. Owing to forward-scattering error, a beam-attenuation meter (beam transmissometer) with a half-angle of receiver acceptance of 1.0° and a path length of 0.1 m can underestimate the true beam attenuation within the bubble cloud by more than 50%. For bubble clouds with a beam attenuation of as much as 100 m^-1, the multiple-scattering error is no more than a few percent. These results are compared with simulations for some example phase functions that are representative of other scattering regimes found in natural waters. The forward-scattering error for the Petzold phase function of turbid waters is 16% for a typical instrument geometry, whereas for the Henyey-Greenstein phase function with the asymmetry parameter of 0.7 and 0.9 the error range is 8-28%.

  17. Pharmaceutical applications of separation of absorption and scattering in near-infrared spectroscopy (NIRS).

    PubMed

    Shi, Zhenqi; Anderson, Carl A

    2010-12-01

    The number of near-infrared (NIR) spectroscopic applications in the pharmaceutical sciences has grown significantly in the last decade. Despite its widespread application, the fundamental interaction between NIR radiation and pharmaceutical materials is often not mechanistically well understood. Separation of absorption and scattering in near-infrared spectroscopy (NIRS) is intended to extract absorption and scattering spectra (i.e., absorption and reduced scattering coefficients) from reflectance/transmittance NIR measurements. The purpose of the separation is twofold: (1) to enhance the understanding of the individual roles played by absorption and scattering in NIRS and (2) to apply the separated absorption and scattering spectra for practical spectroscopic analyses. This review paper surveys the multiple techniques reported to date on the separation of NIR absorption and scattering within pharmaceutical applications, focusing on the instrumentations, mathematical approaches used to separate absorption and scattering and related pharmaceutical applications. This literature review is expected to enhance the understanding and thereby the utility of NIRS in pharmaceutical science. Further, the measurement and subsequent understanding of the separation of absorption and scattering is expected to increase not only the number of NIRS applications, but also their robustness.

  18. Differences in forward angular light scattering distributions between M1 and M2 macrophages.

    PubMed

    Halaney, David L; Zahedivash, Aydin; Phipps, Jennifer E; Wang, Tianyi; Dwelle, Jordan; Saux, Claude Jourdan Le; Asmis, Reto; Milner, Thomas E; Feldman, Marc D

    2015-11-01

    The ability to distinguish macrophage subtypes noninvasively could have diagnostic potential in cancer, atherosclerosis, and diabetes, where polarized M1 and M2 macrophages play critical and often opposing roles. Current methods to distinguish macrophage subtypes rely on tissue biopsy. Optical imaging techniques based on light scattering are of interest as they can be translated into biopsy-free strategies. Because mitochondria are relatively strong subcellular light scattering centers, and M2 macrophages are known to have enhanced mitochondrial biogenesis compared to M1, we hypothesized that M1 and M2 macrophages may have different angular light scattering profiles. To test this, we developed an in vitro angle-resolved forward light scattering measurement system. We found that M1 and M2 macrophage monolayers scatter relatively unequal amounts of light in the forward direction between 1.6 deg and 3.2 deg with M2 forward scattering significantly more light than M1 at increasing angles. The ratio of forward scattering can be used to identify the polarization state of macrophage populations in culture.

  19. A study of the polarization of light scattered by vegetation. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Woessner, P. N.

    1985-01-01

    This study was undertaken in order to better understand the factors that govern the polarization of light scattered from vegetation and soils. The intensity and polarization of light scattered by clover and grass in vivo and soil were measured at a number of different angles of incidence and reflectance. Both individual leaves and natural patches of leaves were measured. The light transmitted through the leaves was found to be negatively polarized. The light scattered from the upper leaf surface was found to be positively polarized in a manner which could be accounted for qualitatively but not quantitatively by the Fresnel reflection coefficients modified by a shadowing function of the form cos sup2 (g/2), where g is the phase angle. Findings indicate that the polarization of light scattered by vegetation is a more complex process than previously thought, and that besides the surface-scattered component of light, the volume-scattered and multiply-scattered components also contribute significantly to the polarization.

  20. Differences in forward angular light scattering distributions between M1 and M2 macrophages

    NASA Astrophysics Data System (ADS)

    Halaney, David L.; Zahedivash, Aydin; Phipps, Jennifer E.; Wang, Tianyi; Dwelle, Jordan; Saux, Claude Jourdan Le; Asmis, Reto; Milner, Thomas E.; Feldman, Marc D.

    2015-11-01

    The ability to distinguish macrophage subtypes noninvasively could have diagnostic potential in cancer, atherosclerosis, and diabetes, where polarized M1 and M2 macrophages play critical and often opposing roles. Current methods to distinguish macrophage subtypes rely on tissue biopsy. Optical imaging techniques based on light scattering are of interest as they can be translated into biopsy-free strategies. Because mitochondria are relatively strong subcellular light scattering centers, and M2 macrophages are known to have enhanced mitochondrial biogenesis compared to M1, we hypothesized that M1 and M2 macrophages may have different angular light scattering profiles. To test this, we developed an in vitro angle-resolved forward light scattering measurement system. We found that M1 and M2 macrophage monolayers scatter relatively unequal amounts of light in the forward direction between 1.6 deg and 3.2 deg with M2 forward scattering significantly more light than M1 at increasing angles. The ratio of forward scattering can be used to identify the polarization state of macrophage populations in culture.

  1. Analysis of Light Scattering by Nanoobjects on a Plane Surface via Discrete Sources Method

    NASA Astrophysics Data System (ADS)

    Eremina, Elena; Eremin, Yuri; Wriedt, Thomas

    2012-12-01

    In the last years light scattering by nanostructures is of interest in different areas of science and technology. Analysis of light scattered by nanostructures is an effective tool for a better understanding of their properties. In this work the Discrete Sources Method (DSM) is applied to model light scattering by nanoparticles on a surface. One of attractive features of the DSM is an ability to account for all the features of the modeled system, such as complex refractive index with frequency dispersion of particles and a substrate, scattering interaction of particle and an interface. To demonstrate the variety of possible applications for the DSM, we concentrated on two practical applications. First is light scattering by a nanorod on a surface, which requires the use of a general 3D version of the DSM. The second case discussed in this chapter is light scattering by a nanoshell, which allows the accounting for the axial symmetry of the problem and essential reduction of calculation time. In both cases light scattering characteristics and their dependence on nanostructure characteristics like size, symmetry, incident angle, particle orientation, refractive index and wavelength are analyzed and discussed.

  2. Polarized light scattering as a probe for changes in chromosome structure

    SciTech Connect

    Shapiro, Daniel Benjamin

    1993-10-01

    Measurements and calculations of polarized light scattering are applied to chromosomes. Calculations of the Mueller matrix, which completely describes how the polarization state of light is altered upon scattering, are developed for helical structures related to that of chromosomes. Measurements of the Mueller matrix are presented for octopus sperm heads, and dinoflagellates. Comparisons of theory and experiment are made. A working theory of polarized light scattering from helices is developed. The use of the first Born approximation vs the coupled dipole approximation are investigated. A comparison of continuous, calculated in this work, and discrete models is also discussed. By comparing light scattering measurements with theoretical predictions the average orientation of DNA in an octopus sperm head is determined. Calculations are made for the Mueller matrix of DNA plectonemic helices at UV, visible and X-ray wavelengths. Finally evidence is presented that the chromosomes of dinoflagellates are responsible for observed differential scattering of circularly-polarized light. This differential scattering is found to vary in a manner that is possibly correlated to the cell cycle of the dinoflagellates. It is concluded that by properly choosing the wavelength probe polarized light scattering can provide a useful tool to study chromosome structure.

  3. Differences in forward angular light scattering distributions between M1 and M2 macrophages

    PubMed Central

    Halaney, David L.; Zahedivash, Aydin; Phipps, Jennifer E.; Wang, Tianyi; Dwelle, Jordan; Saux, Claude Jourdan Le; Asmis, Reto; Milner, Thomas E.; Feldman, Marc D.

    2015-01-01

    Abstract. The ability to distinguish macrophage subtypes noninvasively could have diagnostic potential in cancer, atherosclerosis, and diabetes, where polarized M1 and M2 macrophages play critical and often opposing roles. Current methods to distinguish macrophage subtypes rely on tissue biopsy. Optical imaging techniques based on light scattering are of interest as they can be translated into biopsy-free strategies. Because mitochondria are relatively strong subcellular light scattering centers, and M2 macrophages are known to have enhanced mitochondrial biogenesis compared to M1, we hypothesized that M1 and M2 macrophages may have different angular light scattering profiles. To test this, we developed an in vitro angle-resolved forward light scattering measurement system. We found that M1 and M2 macrophage monolayers scatter relatively unequal amounts of light in the forward direction between 1.6 deg and 3.2 deg with M2 forward scattering significantly more light than M1 at increasing angles. The ratio of forward scattering can be used to identify the polarization state of macrophage populations in culture. PMID:26538329

  4. Scattering of Sculpted Light in Intact Brain Tissue, with implications for Optogenetics

    PubMed Central

    Favre-Bulle, Itia A.; Preece, Daryl; Nieminen, Timo A.; Heap, Lucy A.; Scott, Ethan K.; Rubinsztein-Dunlop, Halina

    2015-01-01

    Optogenetics uses light to control and observe the activity of neurons, often using a focused laser beam. As brain tissue is a scattering medium, beams are distorted and spread with propagation through neural tissue, and the beam’s degradation has important implications in optogenetic experiments. To address this, we present an analysis of scattering and loss of intensity of focused laser beams at different depths within the brains of zebrafish larvae. Our experimental set-up uses a 488 nm laser and a spatial light modulator to focus a diffraction-limited spot of light within the brain. We use a combination of experimental measurements of back-scattered light in live larvae and computational modelling of the scattering to determine the spatial distribution of light. Modelling is performed using the Monte Carlo method, supported by generalised Lorenz–Mie theory in the single-scattering approximation. Scattering in areas rich in cell bodies is compared to that of regions of neuropil to identify the distinct and dramatic contributions that cell nuclei make to scattering. We demonstrate the feasibility of illuminating individual neurons, even in nucleus-rich areas, at depths beyond 100 μm using a spatial light modulator in combination with a standard laser and microscope optics. PMID:26108566

  5. A dark-field scanning spectroscopy platform for localized scatter and fluorescence imaging of tissue

    NASA Astrophysics Data System (ADS)

    Krishnaswamy, Venkataramanan; Laughney, Ashley M.; Paulsen, Keith D.; Pogue, Brian W.

    2011-03-01

    Tissue ultra-structure and molecular composition provide native contrast mechanisms for discriminating across pathologically distinct tissue-types. Multi-modality optical probe designs combined with spatially confined sampling techniques have been shown to be sensitive to this type of contrast but their extension to imaging has only been realized recently. A modular scanning spectroscopy platform has been developed to allow imaging localized morphology and molecular contrast measures in breast cancer surgical specimens. A custom designed dark-field telecentric scanning spectroscopy system forms the core of this imaging platform. The system allows imaging localized elastic scatter and fluorescence measures over fields of up to 15 mm x 15 mm at 100 microns resolution in tissue. Results from intralipid and blood phantom measurements demonstrate the ability of the system to quantify localized scatter parameters despite significant changes in local absorption. A co-registered fluorescence spectroscopy mode is also demonstrated in a protophorphyrin-IX phantom.

  6. Photon counting spectroscopy as done with a Thomson scattering diagnostic

    SciTech Connect

    Den Hartog, D.J.; Ruppert, D.E.

    1993-11-01

    The measurement and reduction of photon counting spectral data is demonstrated within the context of a Thomson scattering diagnostic. This diagnostic contains a microchannel plate (MCP) photomultiplier tube (PMT) as the photon sensing device. The MCP PMT is not an ideal photon sensor, the loss of photoelectrons at the MCP input and the broad charge pulse distribution at the output add to the uncertainty in recorded data. Computer simulations are used to demonstrate an approach to quantification of this added uncertainty and to develop an understanding of its source; the methodology may be applicable to the development of an understanding of photon detectors other than an MCP PMT. Emphasis is placed on the Poisson statistical character of the data, because the assumption that a Gaussian probability distribution is a reasonable statistical description of photon counting data is often questionable. When the count rate is low, the product the possible number of photon counts and the probability of measurement of a single photon is usually not sufficiently large to justify Gaussian statistics. Rather, because probabilities of measurement are so low, the Poisson probability distribution best quantifies the inherent statistical fluctuations in such counting measurements. The method of maximum likelihood is applied to derive the Poisson statistics equivalent of {sub X}{sup 2}. A Poisson statistics based data fitting code is implemented using the Newton-Raphson method of multi-dimensional root finding; we also demonstrate an algorithm to estimate the uncertainties in derived quantities.

  7. Dynamic light scattering studies on charged rod-like fd-virus in dilute aqueous solution

    NASA Astrophysics Data System (ADS)

    Schulz, Susanne F.; Maier, Erich E.; Krause, Rainer; Hagenbüchle, Martin; Deggelmann, Martin; Weber, Reinhart

    1990-06-01

    Time correlation functions of the scattered light intensity are studied in aqueous solutions of charged rod-like fd-virus (L=880 nm, d=6 nm) at various ionic strengths. The short time behavior of the correlation function is dominated by the static structure factor S(q) which is also independently determined from static light scattering experiments. Comparison of correlation functions of solutions with high ionic strength (screened Coulomb interaction) and those of solutions with liquid-like nearest neighbor order (strong Coulomb interaction) shows different single particle diffusion coefficients on medium time scales at high scattering vectors, where mainly single particle properties are observed by light scattering. The single particle diffusion coefficient decreases with increasing structure peak height of the solutions. At low scattering vectors an extra slow mode component of the correlation function is observed for solutions with Coulomb interaction.

  8. Surface enhanced Raman scattering of light by ZnO nanostructures

    NASA Astrophysics Data System (ADS)

    Milekhin, A. G.; Yeryukov, N. A.; Sveshnikova, L. L.; Duda, T. A.; Zenkevich, E. I.; Kosolobov, S. S.; Latyshev, A. V.; Himcinski, C.; Surovtsev, N. V.; Adichtchev, S. V.; Feng, Zhe Chuan; Wu, Chia Cheng; Wuu, Dong Sing; Zahn, D. R. T.

    2011-12-01

    Raman scattering (including nonresonant, resonant, and surface enhanced scattering) of light by optical and surface phonons of ZnO nanocrystals and nanorods has been investigated. It has been found that the nonresonant and resonant Raman scattering spectra of the nanostructures exhibit typical vibrational modes, E 2(high) and A 1(LO), respectively, which are allowed by the selection rules. The deposition of silver nanoclusters on the surface of nanostructures leads either to an abrupt increase in the intensity (by a factor of 103) of Raman scattering of light by surface optical phonons or to the appearance of new surface modes, which indicates the observation of the phenomenon of surface enhanced Raman light scattering. It has been demonstrated that the frequencies of surface optical phonon modes of the studied nanostructures are in good agreement with the theoretical values obtained from calculations performed within the effective dielectric function model.

  9. Electromagnetic and Light Scattering by Nonspherical Particles XV: Celebrating 150 Years of Maxwell's Electromagnetics

    NASA Technical Reports Server (NTRS)

    Macke, Andreas; Mishchenko, Michael I.

    2015-01-01

    The 15th Electromagnetic and Light Scattering Conference (ELS-XV) was held in Leipzig, Germany from 21 to 26 of June 2015. This conference built on the great success of the previous meetings held in Amsterdam (1995), Helsinki(1997) [2], New York City(1998) [3], Vigo (1999),Halifax (2000), Gainesville (2002), Bremen (2003), Salobreña (2005), St. Petersburg (2006), Bodrum (2007), Hatfield (2008), Helsinki (2010), Taormina (2011), and Lille as well as the workshops held in Bremen (1996,1998) and Moscow (1997). As usual, the main objective of this conference was to bring together scientists, engineers, and PhD students studying various aspects of electromagnetic scattering and to provide a relaxed atmosphere for in-depth discussion of theory, measurements, and applications. Furthermore, ELS-XV supported the United Nations "Year of Light" and celebrated the150th anniversary of Maxwell's electromagnetics. Maxwell's paper on "A Dynamical Theory of the Electromagnetic Field" was published in1865 and has widely been acknowledged as one of the supreme achievements in the history of science. The conference was attended by136 scientists from 22 countries. The scientific program included two plenary lectures, 16 invited reviews, 88 contributed oral talks, and 70 poster presentations. The program and the abstracts of conference presentations are available at the conference website http://www.els-xv-2015.net/home.html. Following the well-established ELS practice and with Elsevier's encouragement, we solicited full-size papers for a topical issue of the Journal of Quantitative Spectroscopy and Radiative Transfer (JQSRT). The result of this collective effort is now in the reader's hands. As always, every invited review and regular paper included in this topical issue has undergone the same rigorous peer review process as any other manuscript published in the JQSRT.

  10. Diffusivities of Ternary Mixtures of n-Alkanes with Dissolved Gases by Dynamic Light Scattering.

    PubMed

    Heller, Andreas; Giraudet, Cédric; Makrodimitri, Zoi A; Fleys, Matthieu S H; Chen, Jiaqi; van der Laan, Gerard P; Economou, Ioannis G; Rausch, Michael H; Fröba, Andreas P

    2016-10-12

    Theoretical approaches suggest that dynamic light scattering (DLS) signals from low-molecular-weight ternary mixtures are governed by fluctuations in temperature as well as two individual contributions from fluctuations in concentration that are related to the eigenvalues of the Fick diffusion matrix. Until now, this could not be proven experimentally in a conclusive way. In the present study, a detailed analysis of DLS signals in ternary mixtures consisting of n-dodecane (n-C12H26) and n-octacosane (n-C28H58) with dissolved hydrogen (H2), carbon monoxide (CO), or water (H2O) as well as of n-C12H26 or n-C28H58 with dissolved H2 and CO is given for temperatures up to 523 K and pressures up to 4.1 MPa. Thermal diffusivities of pure n-C12H26 and n-C28H58 as well as thermal and mutual diffusivities of their binary mixtures being the basis for the ternary mixtures with dissolved gas were studied for comparison purposes. For the investigated ternary mixtures, three individual signals could be distinguished in the time-resolved analysis of scattered light intensity by using photon correlation spectroscopy (PCS). For the first time, it could be evidenced that these signals are clearly associated with hydrodynamic modes. In most cases, the fastest mode observable for ternary mixtures is associated with the thermal diffusivity. The two further modes obviously related to the molecular mass transport are observable on different time scales and comparable to the modes associated with the concentration fluctuations in the respective binary mixtures. Comparison of the experimental data with results from molecular dynamics simulations revealed very good agreement.

  11. Evaluation of light scattering properties and chromophore concentrations in skin tissue based on diffuse reflectance signals at isosbestic wavelengths of hemoglobin

    NASA Astrophysics Data System (ADS)

    Yokokawa, Takumi; Nishidate, Izumi

    2016-04-01

    We investigate a method to evaluate light-scattering properties and chromophore concentrations in human skin tissue through diffuse reflectance spectroscopy using the reflectance signals acquired at isosbestic wavelengths of hemoglobin (420, 450, 500, and 585 nm). In the proposed method, Monte Carlo simulation-based empirical formulas are used to specify the scattering parameters of skin tissue, such as the scattering amplitude a and the scattering power b, as well as the concentration of melanin C m and the total blood concentration C tb. The use of isosbestic wavelengths of hemoglobin enables the values of C m, C tb, a, and b to be estimated independently of the oxygenation of hemoglobin. The spectrum of the reduced scattering coefficient is reconstructed from the scattering parameters. Experiments using in vivo human skin tissues were performed to confirm the feasibility of the proposed method for evaluating the changes in scattering properties and chromophore concentrations in skin tissue. The experimental results revealed that light scattering is significantly reduced by the application of a glycerol solution, which indicates an optical clearing effect due to osmotic dehydration and the matching of the refractive indices of scatterers in the epidermis.

  12. Multibeam long-path differential optical absorption spectroscopy instrument: a device for simultaneous measurements along multiple light paths.

    PubMed

    Pundt, Irene; Mettendorf, Kai Uwe

    2005-08-10

    A novel long-path differential optical absorption spectroscopy (DOAS) apparatus for measuring tropospheric trace gases and the first results from its use are presented: We call it the multibeam instrument. It is the first active DOAS device that emits several light beams simultaneously through only one telescope and with only one lamp as a light source, allowing simultaneous measurement along multiple light paths. In contrast to conventional DOAS instruments, several small mirrors are positioned near the lamp, creating multiple virtual light sources that emit one light beam each in one specific direction. The possibility of error due to scattering between the light beams is negligible. The trace-gas detection limits of NO2, SO2, O3, and H2CO are similar to those of the traditional long-path DOAS instrument.

  13. Light-scattering thermal cross-linking material using morphology of nanoparticle free polymer blends

    NASA Astrophysics Data System (ADS)

    Takei, Satoshi

    2015-03-01

    A newly light-scattering thermal cross-linking material based on self-assembly for forming the morphology of nanoparticle free polymer blends was reported. The material design concept to use light-scattering thermal cross-linking material with high uniformity of light on display panel from LED for high quality such as brightness and evenness, mechanical properties, and gas and water barrier properties. The high light scattering rate of 8 % at 350-450 nm of wavelength, fast cure film at 140 ºC and 120 s, and thermal stability at 190 ºC in bake condition for high productivity were indicated in the light-scattering thermal cross-linking material using the nanoparticle free polymers with carboxylic acid functional groups. These novel system using morphology of nanoparticle free polymer blends in light-scattering package material for a LCD using LED was a valuable approach to the design of material formulations for newly light-scattering thermal cross-linking material.

  14. Utilization of light scattering in transmission laser welding of medical devices

    NASA Astrophysics Data System (ADS)

    von Bülow, Jon Fold; Bager, Kim; Thirstrup, Carsten

    2009-11-01

    This paper reports on optimization of material parameters in transmission laser welding of polymers including light absorption, light scattering and the thermal properties of the polymers. A criterion for making an optimized transmission laser weld between a transparent polymer part and an absorbing and scattering polymer part is formulated as a required thickness of the melt-zone in the transparent part with a corresponding minimum-line-energy-for-welding ( MLEW). Experimental data of MLEW are presented for a medical device application involving joining polyethylene-octene parts for various concentrations of near-infrared absorber and titanium dioxide light scattering particles. Numerical and analytical models yield good agreement to the experimental data and enable optimization of the transmission laser welding process. By utilization of light scattering, the laser line-energy required for joining two polymer parts can be reduced by a factor up to three, enabling a corresponding reduction of the cycle time in the manufacturing process.

  15. Interfaces roughness cross correlation properties and light scattering of optical thin films

    NASA Astrophysics Data System (ADS)

    Pan, Yong-qiang; Wu, Zhen-sen; Hang, Ling-xia

    2009-05-01

    In order to study optical thin films interfaces roughness cross correlation properties and light scattering, theoretical models of optical thin films interfaces roughness light scattering are concisely presented. Furthermore, influence of interfaces roughness cross-correlation properties to light scattering was analyzed by total backscattering. Moreover, TiO2 single optical films thickness, substrate roughness of K9 glass and ion beam assisted deposition (IBAD) technique effect on interface roughness cross correlation properties were studied by experiments, respectively. The results showed that theoretical results obtained by integrating vector light scattering were agreed well with experimental results. The interfaces roughness cross-correlation decrease with the increase of films thickness or with the decrease of substrates roughness. When ion beam assisted deposition was used, a high degree of cross-correlated can be obtained.

  16. Spectrum of laser light scattered by nanoparticles in an ablation-induced cavitation bubble

    NASA Astrophysics Data System (ADS)

    Takeuchi, Masato; Sasaki, Koichi

    2016-04-01

    The spectrum of the laser light scattered by nanoparticles in a cavitation bubble, which was induced by laser ablation of a titanium target in water, was measured using a triple-grating spectrograph. The scattered laser light observed at 100 \\upmu s after laser ablation had no wavelength-shifted component, suggesting that nanoparticles at this delay time were metallic. The wavelength-shifted component was observed in the spectrum at a delay time of 200 \\upmu s, suggesting the formation of oxidized nanoparticles. However, we observed no peaks in the spectrum of the scattered laser light in the present in situ laser-light scattering experiment. On the other hand, we observed clear peaks in the Raman spectrum of synthesized nanoparticles. The experimental results suggest slow crystallization of nanoparticles in liquid in liquid-phase laser ablation.

  17. In vivo measurement of mid-infrared light scattering from human skin

    PubMed Central

    Michel, Anna P. M.; Liakat, Sabbir; Bors, Kevin; Gmachl, Claire F.

    2013-01-01

    Two mid-infrared light sources, a broadband source from a Fourier Transform Infrared Spectrometer (FTIR) and a pulsed Quantum Cascade (QC) Laser, are used to measure angle-resolved backscattering in vivo from human skin across a broad spectral range. Scattering profiles measured using the FTIR suggest limited penetration of the light into the skin, with most of the light interacting with the stratum corneum layer of the epidermis. Scattering profiles from the QC laser show modulation patterns with angle suggesting interaction with scattering centers in the skin. The scattering is attributed to interaction of the laser light with components such as collagen fibers and capillaries in the dermis layer of the skin. PMID:23577287

  18. Brillouin-scattering-induced transparency and non-reciprocal light storage

    PubMed Central

    Dong, Chun-Hua; Shen, Zhen; Zou, Chang-Ling; Zhang, Yan-Lei; Fu, Wei; Guo, Guang-Can

    2015-01-01

    Stimulated Brillouin scattering is a fundamental interaction between light and travelling acoustic waves and arises primarily from electrostriction and photoelastic effects, with an interaction strength several orders of magnitude greater than that of other relevant non-linear optical processes. Here we report an experimental demonstration of Brillouin-scattering-induced transparency in a high-quality whispering-gallery-mode optical microresonantor. The triply resonant Stimulated Brillouin scattering process underlying the Brillouin-scattering-induced transparency greatly enhances the light–acoustic interaction, enabling the storage of light as a coherent, circulating acoustic wave with a lifetime up to 10 μs. Furthermore, because of the phase-matching requirement, a circulating acoustic wave can only couple to light with a given propagation direction, leading to non-reciprocal light storage and retrieval. These unique features establish a new avenue towards integrated all-optical switching with low-power consumption, optical isolators and circulators. PMID:25648234

  19. Coherent Scattering of Near-Resonant Light by a Dense Microscopic Cold Atomic Cloud

    NASA Astrophysics Data System (ADS)

    Jennewein, S.; Besbes, M.; Schilder, N. J.; Jenkins, S. D.; Sauvan, C.; Ruostekoski, J.; Greffet, J.-J.; Sortais, Y. R. P.; Browaeys, A.

    2016-06-01

    We measure the coherent scattering of light by a cloud of laser-cooled atoms with a size comparable to the wavelength of light. By interfering a laser beam tuned near an atomic resonance with the field scattered by the atoms, we observe a resonance with a redshift, a broadening, and a saturation of the extinction for increasing atom numbers. We attribute these features to enhanced light-induced dipole-dipole interactions in a cold, dense atomic ensemble that result in a failure of standard predictions such as the "cooperative Lamb shift". The description of the atomic cloud by a mean-field model based on the Lorentz-Lorenz formula that ignores scattering events where light is scattered recurrently by the same atom and by a microscopic discrete dipole model that incorporates these effects lead to progressively closer agreement with the observations, despite remaining differences.

  20. Discrete Sources Method for light scattering analysis of non-axisymmetric features of a substrate

    NASA Astrophysics Data System (ADS)

    Eremin, Yuri; Wriedt, Thomas

    2016-01-01

    The Discrete Sources Method (DSM) has been extended to analyze polarized light scattering by non-axial symmetric nano-sized features on a plane substrate. A detailed description of the corresponding numerical scheme is provided. Using a "fictitious" particle approach the new DSM model enables to consider scattering from such substrate defects as a line bump and a line pit. The developed computer model has been employed for demonstrating the ability to perform a comparative analysis of light scattering from such line features. Simulation results corresponding to the Differential Scattering Cross-Section (DSC) and the integral response for P/S polarized light are presented. It was found that the integral response can change by an order of magnitude depending on the orientation of the linear defect with respect to the direction of the incident laser light. In addition, it was shown that some defects can turn out to be "invisible" if an oblique angle of incidence is chosen.

  1. Cancer detection using NIR elastic light scattering and tissue fluorescence imaging

    SciTech Connect

    Demos, S G; Staggs, M; Radousky, H B; Gandour-Edwards, R; deVere White, R

    2000-12-04

    Near infrared imaging using elastic light scattering and tissue fluorescence under long-wavelength laser excitation are explored for cancer detection. Various types of normal and malignant human tissue samples were utilized in this investigation.

  2. Light scattering by marine algae: two-layer spherical and nonspherical models

    NASA Astrophysics Data System (ADS)

    Quirantes, Arturo; Bernard, Stewart

    2004-11-01

    Light scattering properties of algae-like particles are modeled using the T-matrix for coated scatterers. Two basic geometries have been considered: off-centered coated spheres and centered spheroids. Extinction, scattering and absorption efficiencies, plus scattering in the backward plane, are compared to simpler models like homogeneous (Mie) and coated (Aden-Kerker) models. The anomalous diffraction approximation (ADA), of widespread use in the oceanographic light-scattering community, has also been used as a first approximation, for both homogeneous and coated spheres. T-matrix calculations show that some light scattering values, such as extinction and scattering efficiencies, have little dependence on particle shape, thus reinforcing the view that simpler (Mie, Aden-Kerker) models can be applied to infer refractive index (RI) data from absorption curves. The backscattering efficiency, on the other hand, is quite sensitive to shape. This calls into question the use of light scattering techniques where the phase function plays a pivotal role, and can help explain the observed discrepancy between theoretical and experimental values of the backscattering coefficient in observed in oceanic studies.

  3. Modeling Light Scattering in Tissue as Continuous Random Media Using a Versatile Refractive Index Correlation Function

    PubMed Central

    Rogers, Jeremy D.; Radosevich, Andrew J.; Yi, Ji; Backman, Vadim

    2014-01-01

    Optical interactions with biological tissue provide powerful tools for study, diagnosis, and treatment of disease. When optical methods are used in applications involving tissue, scattering of light is an important phenomenon. In imaging modalities, scattering provides contrast, but also limits imaging depth, so models help optimize an imaging technique. Scattering can also be used to collect information about the tissue itself providing diagnostic value. Therapies involving focused beams require scattering models to assess dose distribution. In all cases, models of light scattering in tissue are crucial to correctly interpreting the measured signal. Here, we review a versatile model of light scattering that uses the Whittle–Matérn correlation family to describe the refractive index correlation function Bn (rd). In weakly scattering media such as tissue, Bn (rd) determines the shape of the power spectral density from which all other scattering characteristics are derived. This model encompasses many forms such as mass fractal and the Henyey–Greenstein function as special cases. We discuss normalization and calculation of optical properties including the scattering coefficient and anisotropy factor. Experimental methods using the model are also described to quantify tissue properties that depend on length scales of only a few tens of nanometers. PMID:25587211

  4. A review of light-scattering techniques for the study of colloids in natural waters

    USGS Publications Warehouse

    Rees, T.F.

    1987-01-01

    In order to understand the movement of colloidal materials in natural waters, we first need to have a means of quantifying their physical characteristics. This paper reviews three techniques which utilize light-scattering phenomena to measure the translational diffusion coefficient, the rotational diffusion coefficient, and the electrophoretic mobility of colloids suspended in water. Primary emphasis is to provide sufficient theoretical detail so that hydrologists can evaluate the utility of photon correlation spectrometry, electrophoretic light scattering, and electric birefringence analysis. ?? 1987.

  5. Detecting quantum coherence of Bose gases in optical lattices by scattering light intensity in cavity.

    PubMed

    Zhou, Xiaoji; Xu, Xu; Yin, Lan; Liu, W M; Chen, Xuzong

    2010-07-19

    We propose a new method of detecting quantum coherence of a Bose gas trapped in a one-dimensional optical lattice by measuring the light intensity from Raman scattering in cavity. After pump and displacement process, the intensity or amplitude of scattering light is different for different quantum states of a Bose gas, such as superfluid and Mott-Insulator states. This method can also be useful to detect quantum states of atoms with two components in an optical lattice.

  6. Measurements of near forward scattered laser light in a large ICF plasma

    SciTech Connect

    Moody, J.D., LLNL

    1998-06-02

    We describe an instrument which measures the angular spread and spectrum of near forward scattered laser light from a probe beam in a long scalelength laser-plasma. The instrument consists of a combination of time integrating and time resolving detectors which measure the scattered light amplitude over four orders of magnitude for a range of angles. These measurements allow us to study the beam spray resulting from various laser and plasma conditions and determine the density fluctuations associated with this beam spray.

  7. Protein crystal nucleation kinetics using relative light-scattering techniques: Center director's discretionary fund

    NASA Technical Reports Server (NTRS)

    Pusey, Marc Lee

    1989-01-01

    Light-scattering intensity measurements are a sensitive method for following changes in the hydrodynamic radius of particles in solution. The approach used in this report utilizes the light-scattering intensity ratios of a polydisperse to a monodisperse system. By numerically modeling the process, and fitting the model curves to the data, estimates have been obtained for the dimerization equilibrium constant, the dimer + dimer yields tetramer equilibrium constant, and the association rate constant for the dimerization process.

  8. Dynamic light scattering investigations of nanoparticle aggregation following a light-induced pH jump

    NASA Astrophysics Data System (ADS)

    Murphy, Ryan J.; Pristinski, Denis; Migler, Kalman; Douglas, Jack F.; Prabhu, Vivek M.

    2010-05-01

    There are many important processes where the stability of nanoparticles can change due to changes in solution environment. These processes are often difficult to study under controlled changes to the solution conditions. Dynamic light scattering was used to measure the initial kinetics of aggregation of carboxylated polystyrene nanoparticles after well-defined pH jumps using aqueous solutions of photoacid generator (PAG). With this approach, the pH of the solution was controlled by exposure to ultraviolet (UV) light without the delays from mixing or stirring. The aggregation kinetics of the nanoparticles was extremely sensitive to the solution pH. The UV exposure dose is inversely correlated with the resulting surface charge of the nanoparticles. Decreasing pH decreases the electrostatic repulsion force between particles and leads to aggregation. The reaction-limited or diffusion-limited aggregation kinetics was sensitive to the pH quench depth, relative to the acid-equilibrium constant (pKa) of the surface carboxylic acid groups on the nanoparticles. Since numerous PAGs are commercially available, this approach provides a flexible method to study the aggregation of a variety of solvent-dispersed nanoparticle systems.

  9. Light scattering by conducting surfaces with one-dimensional roughness

    NASA Astrophysics Data System (ADS)

    O'Donnell, Kevin A.; Knotts, Michael E.; Michel, T. R.

    1994-10-01

    We describe experimental measurements of the scattering properties of two conducting surfaces with 1D roughness. The surfaces have been fabricated in photoresist and have been characterized with a stylus that is small compared to the surface correlation length. In studies of diffuse scatter, we present measurements of the four unique elements of the Stokes matrix. Backscattering enhancement and associated polarization effects are observed for the rougher surface while behavior consistent with tangent plane models is seen for the smoother surface. The polarization-dependence of the coherent scatter is also investigated, and comparisons are made with the results calculated for a flat surface. Finally, we briefly present results for the angular correlation functions of intensity, where the coherent effects that produce backscattering enhancement are more directly observed.

  10. Anomalous Light Scattering by Topological PT-symmetric Particle Arrays

    PubMed Central

    Ling, C. W.; Choi, Ka Hei; Mok, T. C.; Zhang, Zhao-Qing; Fung, Kin Hung

    2016-01-01

    Robust topological edge modes may evolve into complex-frequency modes when a physical system becomes non-Hermitian. We show that, while having negligible forward optical extinction cross section, a conjugate pair of such complex topological edge modes in a non-Hermitian -symmetric system can give rise to an anomalous sideway scattering when they are simultaneously excited by a plane wave. We propose a realization of such scattering state in a linear array of subwavelength resonators coated with gain media. The prediction is based on an analytical two-band model and verified by rigorous numerical simulation using multiple-multipole scattering theory. The result suggests an extreme situation where leakage of classical information is unnoticeable to the transmitter and the receiver when such a -symmetric unit is inserted into the communication channel. PMID:27905504

  11. Light scattering by absorbing hexagonal ice crystals in cirrus clouds.

    PubMed

    Zhang, J; Xu, L

    1995-09-01

    An improved ray-optics theory for single scattering and polarization of hexagonal columns and plates randomly oriented in space has been developed by considering absorption and by using the Chebyshev solution for diffraction integrals. The vector-tracing method and statistics technique of random sampling are employed. The equivalent forms of Snell's law and Fresnel formulas for absorbing ice crystals are derived, and two equivalent optical constants, m' and m″, are obtained. Comparison is made of the computed results of our model and the Takano and Liou model for asymmetry factors, single-scattering albedos, and scattering phase matrix elements. Some characteristics of our model are discussed, and these analyses demonstrate that our ray-optics model is practical and much improved.

  12. Anomalous Light Scattering by Topological PT-symmetric Particle Arrays

    NASA Astrophysics Data System (ADS)

    Ling, C. W.; Choi, Ka Hei; Mok, T. C.; Zhang, Zhao-Qing; Fung, Kin Hung

    2016-12-01

    Robust topological edge modes may evolve into complex-frequency modes when a physical system becomes non-Hermitian. We show that, while having negligible forward optical extinction cross section, a conjugate pair of such complex topological edge modes in a non-Hermitian -symmetric system can give rise to an anomalous sideway scattering when they are simultaneously excited by a plane wave. We propose a realization of such scattering state in a linear array of subwavelength resonators coated with gain media. The prediction is based on an analytical two-band model and verified by rigorous numerical simulation using multiple-multipole scattering theory. The result suggests an extreme situation where leakage of classical information is unnoticeable to the transmitter and the receiver when such a -symmetric unit is inserted into the communication channel.

  13. Two-photon vibrational spectroscopy for biosciences based on surface-enhanced hyper-Raman scattering

    PubMed Central

    Kneipp, Janina; Kneipp, Harald; Kneipp, Katrin

    2006-01-01

    Two-photon excitation is gaining rapidly in interest and significance in spectroscopy and microscopy. Here we introduce a new approach that suggests versatile optical labels suitable for both one- and two-photon excitation and also two-photon-excited ultrasensitive, nondestructive chemical probing. The underlying spectroscopic effect is the incoherent inelastic scattering of two photons on the vibrational quantum states called hyper-Raman scattering (HRS). The rather weak effect can be strengthened greatly if HRS takes place in the local optical fields of gold and silver nanostructures. This so-called surface-enhanced HRS (SEHRS) is the two-photon analogue to surface-enhanced Raman scattering (SERS). SEHRS provides structurally sensitive vibrational information complementary to those obtained by SERS. SEHRS combines the advantages of two-photon spectroscopy with the structural information of vibrational spectroscopy and the high-sensitivity and nanometer-scale local confinement of plasmonics-based spectroscopy. We infer effective two-photon cross-sections for SEHRS on the order of 10−46 to 10−45 cm4·s, similar to or higher than the best “action” cross-sections (product of the two-photon absorption cross-section and fluorescence quantum yield) for two-photon fluorescence, and we demonstrate HRS on biological structures such as single cells after incubation with gold nanoparticles. PMID:17088534

  14. Effect of nonsphericity of scattering centers on light transport in turbid media

    NASA Astrophysics Data System (ADS)

    Mourant, Judith R.; Aida, Toru; Coburn, Leslie; Ramachandran, Janak

    2004-07-01

    The scattering centers in cells are not spheres, however, in most modeling of light transport, the scattering centers are assumed to be spherical. For example, in Monte Carlo simulations a Mie or Henyey-Greenstein phase function is often used. It is known that an elliptical particle will have a different phase function than a spherical particle. In particular there are differences in the phase functions for scattering polarized light. To examine how these changes in phase function affect light transport in tissue, we have developed a Monte Carlo code for light transport that uses elliptical scatterers. The phase functions are calculated using a T-matrix code and the propagation of polarized photons is performed in a manner analagous to that used by Bartel and Hielscher. Our initial results indicate that for narrow particle distributions the difference in shape can cause large differences in the intensity and polarization properties of the diffusely reflected light. For a mixture of particle sizes, however, there is a much smaller difference in the properties of the diffusely scattered light. Results are presented for both narrow and broad distributions of scatter sizes relevant to tissue.

  15. Features of polarization decay in the transition between the low-step and multiple scattering of laser light

    NASA Astrophysics Data System (ADS)

    Zimnyakov, D. A.; Yuvchenko, S. A.; Taskina, L. A.; Alonova, M. V.; Isaeva, E. A.; Isaeva, A. A.; Ushakova, O. V.

    2016-04-01

    The effect of increase in the uncertainty of local polarization states of laser light forward scattered by random media was studied in the experiments with phantom scatterers. At macroscopic level this effect is related to decay in the degree of polarization of scattered light in the course of transition from single to multiple scattering. Gelatin layers with embedded titania particles were used as the phantom scatterers. Features of distributions of local polarization states in various polarization coordinates were considered.

  16. Monte Carlo simulation of light scattering from size distributed homogenous and coated spherical particles

    NASA Astrophysics Data System (ADS)

    Gogoi, Ankur

    Light scattering is a subject of intensive research at the present time in diverse fields of research namely, physics, astronomy, meteorology, biology, nanotechnology, etc. Observation and theoretical calculation of the absorption and scattering properties of particles, whose size ranges from micrometer to nanometer, are not only essential to deduce their physical properties but also capable of giving useful information for better understanding of radiation transfer through a medium containing such scatterer. In addition to such experimental and theoretical studies on light scattering by particulate matter several other groups have been extensively using Monte Carlo (MC) method to simulate light (photon) propagation in scattering media. Importantly such methods of simulating light scattering properties of artificial particles are proving to be a very useful tool in verifying the experimental observations with real samples as well as providing new clues to improve the accuracy of the existing theoretical models. In this contribution we report a MC method developed by implementing Mie theory to simulate the light scattering pattern from size distributed homogenous and coated spherical particles in single scattering regime. The computer program was written in ANSI C-language. The accuracy, efficiency and reliability of the MC method were validated by comparing the results generated by using the MC method with other benchmark theoretical results and experimental results with standard samples. Notably the MC method reported here is found to be stable even for very large spherical particles (size parameters > 1000) with large values of real (= 10) and imaginary part (= 10) of the refractive index. The promising field of application of the reported MC method will be in simulating the light (or electromagnetic) scattering properties of different types of planetary and interplanetary dust particles.

  17. The 0.5 micrometer-2.2 micrometer Scattered Light Spectrum of the Disk Around TW Hya

    NASA Technical Reports Server (NTRS)

    Debes, John H.; Jang-Condell, Hannah; Weinberger, Alycia J.; Roberg, Aki; Schneider, Glenn

    2012-01-01

    We present a 0.5-2.2micron scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved HST STIS spectroscopy and NICMOS coronagraphic images of the disk. \\Ve investigate the morphology at the disk at distances> 40 AU over this wide range of wavelengths. We measure the surface brightness, azimuthal symmetry, and spectral character of the disk as a function of radius. We find that the scattering efficiency of the dust is largely neutral to blue over the observed wavelengths. We find a good fit to the data over a wide range of distances from the star if we use a model disk with a partial gap of 30% depth at 80 AU and with steep disk truncation exterior to 100 AU. If the gap is caused by a planetary companion in the process of accreting disk gas, it must be less than 20 Solar mass.

  18. Double scattering of light from Biophotonic Nanostructures with short-range order.

    PubMed

    Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Prum, Richard O; Mochrie, Simon G J; Dufresne, Eric R; Cao, Hui

    2010-05-24

    We investigate the physical mechanism for color production by isotropic nanostructures with short-range order in bird feather barbs. While the primary peak in optical scattering spectra results from constructive interference of singly-scattered light, many species exhibit secondary peaks with distinct characteristic. Our experimental and numerical studies show that these secondary peaks result from double scattering of light by the correlated structures. Without an analog in periodic or random structures, such a phenomenon is unique for short-range ordered structures, and has been widely used by nature for non-iridescent structural coloration.

  19. Investigation of light scattering as a technique for detecting discrete soot particles in a luminous flame

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The practicability of using a classical light-scattering technique, involving comparison of angular scattering intensity patterns with theoretically determined Mie and Rayleight patterns, to detect discrete soot particles (diameter less than 50 nm) in premixed propane/air and propane/oxygen-helium flames is considered. The experimental apparatus employed in this investigation included a laser light source, a flat-flame burner, specially coated optics, a cooled photomultiplier detector, and a lock-in voltmeter readout. Although large, agglomerated soot particles were detected and sized, it was not possible to detect small, discrete particles. The limiting factor appears to be background scattering by the system's optics.

  20. Bragg scattering of light in vacuum structured by strong periodic fields.

    PubMed

    Kryuchkyan, Gagik Yu; Hatsagortsyan, Karen Z

    2011-07-29

    Elastic scattering of laser radiation due to vacuum polarization by spatially modulated strong electromagnetic fields is considered. The Bragg interference arising at a specific impinging direction of the probe wave concentrates the scattered light in specular directions. The interference maxima are enhanced with respect to the usual vacuum polarization effect proportional to the square of the number of modulation periods within the interaction region. The Bragg scattering can be employed to detect the vacuum polarization effect in a setup of multiple crossed superstrong laser beams with parameters envisaged in the future Extreme Light Infrastructure.