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Sample records for resonance scattering spectral

  1. Spectral shapes of surface-enhanced resonance Raman scattering sensitive to the refractive index of media around single Ag nanoaggregates

    NASA Astrophysics Data System (ADS)

    Yoshida, Ken-ichi; Itoh, Tamitake; Biju, Vasudevanpillai; Ishikawa, Mitsuru; Ozaki, Yukihiro

    2009-12-01

    We found large spectral changes in surface-enhanced resonance Raman scattering (SERRS) with increasing refractive index of media around single Ag nanoaggregates. We analyzed relationship between the spectral changes in SERRS and those in plasma (plasmon) resonance based on the twofold electromagnetic (EM) enhancement theory. The analysis revealed that the changes in SERRS spectra are induced by changes in spectral shapes of twofold EM enhancement factors, which arise from coupling of plasma resonance with both incident and Raman scattering light.

  2. The local spin-flip spectral distribution obtained by resonant x-ray Raman scattering

    NASA Astrophysics Data System (ADS)

    de Groot, Frank; Kuiper, Pieter; Sawatzky, George

    1998-03-01

    We will show that resonant x-ray Raman scattering can be used to study the local spin-flip excitation spectral distribution in magnetically ordered 3d transition metal compounds. We demonstrate with realistic calculations on the 3p x-ray absorption edge of a Cu^2+ compound and the 2p edge of a Ni^2+ compound that the scattered x-ray energy and intensity distribution contains the excitation spectrum resulting from a single local spin-flip, as well as dd excitations accompanied by local spin flip satellites. We develop the theory describing this effect and discuss the polarization conditions which can be used to observe these effects.

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

    NASA Astrophysics Data System (ADS)

    Wen, Guiqing; Yang, Duo; Jiang, Zhiliang

    2014-01-01

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

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

    PubMed

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

    2016-09-05

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

  5. A sensitive enzyme-catalytic nanogold-resonance scattering spectral assay for alkaline phosphate.

    PubMed

    Jiang, Zhiliang; Wu, Meng; Liu, Gaosan; Liang, Aihui

    2012-06-01

    In pH 8.9 Tris-HCl buffer solutions, alkaline phosphatase (ALP) catalyzed the hydrolysis of ascorbic acid 2-phosphate (AAP) substrate to form ascorbic acid. Then H(3)PO(4) was added to stop the enzymatic reaction and HAuCl(4) was used to react with ascorbic acid to generate gold nanoparticles that exhibited a resonance scattering (RS) peak at 600 nm. Under the selected conditions, when the activity of ALP increased, the formed ascorbic acid and gold nanoparticles also increased. Thus, the RS intensity at 600 nm enhanced linearly. The linear range was 0.06-22 U/L, with a detection limit of 0.03 U/L. The ALP in serum was analyzed, and the results were in agreement with those of the fluorescence method.

  6. Comparison of temporal and spectral scattering methods using acoustically large breast models derived from magnetic resonance images

    PubMed Central

    Hesford, Andrew J.; Tillett, Jason C.; Astheimer, Jeffrey P.; Waag, Robert C.

    2014-01-01

    Accurate and efficient modeling of ultrasound propagation through realistic tissue models is important to many aspects of clinical ultrasound imaging. Simplified problems with known solutions are often used to study and validate numerical methods. Greater confidence in a time-domain k-space method and a frequency-domain fast multipole method is established in this paper by analyzing results for realistic models of the human breast. Models of breast tissue were produced by segmenting magnetic resonance images of ex vivo specimens into seven distinct tissue types. After confirming with histologic analysis by pathologists that the model structures mimicked in vivo breast, the tissue types were mapped to variations in sound speed and acoustic absorption. Calculations of acoustic scattering by the resulting model were performed on massively parallel supercomputer clusters using parallel implementations of the k-space method and the fast multipole method. The efficient use of these resources was confirmed by parallel efficiency and scalability studies using large-scale, realistic tissue models. Comparisons between the temporal and spectral results were performed in representative planes by Fourier transforming the temporal results. An RMS field error less than 3% throughout the model volume confirms the accuracy of the methods for modeling ultrasound propagation through human breast. PMID:25096103

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

    PubMed

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

    2016-06-05

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  9. Spectral line shapes of U M2 - and As K -edge resonant x-ray scattering in the two antiferromagnetic phases of UAs

    NASA Astrophysics Data System (ADS)

    Normile, P. S.; Wilkins, S. B.; Detlefs, B.; Mannix, D.; Blackburn, E.; Bouchenoire, L.; Bernhoeft, N.; Lander, G. H.

    2007-05-01

    We present resonant x-ray scattering measurements on uranium arsenide at the U M2 and As K absorption edges. The studies at both edges relate to aspects of the hybridization (involving the 5f states) in UAs. At the U M2 edge, the spectral line shapes are found to differ between the two antiferromagnetic phases of UAs. In the “type-I” phase, the line shapes may be fitted using a single resonant component, whereas in the “type-IA” phase, a second resonant component, 3.5eV above the first component, is required to fit the line shapes in the rotated polarization (σ→π) scattering channel. The possibility that the single (first) component in the type-I (type-IA) phase corresponds to E2 scattering due to the ordered 5f magnetic-dipole moments and that in the type-IA phase the second component represents an E1 process involving polarized 6d (U) states is considered. Similar line shapes are observed for the two antiferromagnetic phases at the As K edge, a result which is in discordance with a recent theoretical prediction. The experimentally observed As K -edge line shape has an asymmetrical form in both phases, which possibly relates to As 4p -band effects unaccounted for in the theory.

  10. Spectral Change in 3d-4f Resonant Inelastic X-ray Scattering of Ce Intermetallics Across the Transition between Kondo Singlet and Localized-Spin State

    NASA Astrophysics Data System (ADS)

    Sasabe, Norimasa; Tonai, Hironori; Uozumi, Takayuki

    2017-09-01

    The spectral change in the 3d resonant X-ray inelastic scattering (RIXS) induced by the spin-state transition between Kondo singlet (KS) and localized spin (LS) state is theoretically investigated for γ-like Ce intermetallics by means of a single impurity Anderson model. The basis configurations with an electron-hole pair are included in the calculation within the configuration interaction scheme, in addition to the intra-atomic full multiplet coupling of the Ce impurity. A distinct spectral change is found across the KS-LS transition in the RIXS excited at the charge-transfer satellite of the 3d X-ray absorption spectrum (XAS) under a polarized geometry. In contrast, the 3d XAS and RIXS spectra under a depolarized geometry are rather insensitive to the spin-state transition.

  11. A highly sensitive and selective resonance scattering spectral assay for potassium ion based on aptamer and nanosilver aggregation reactions.

    PubMed

    Cai, Wei; Fan, Yanyan; Jiang, Zhiliang; Yao, Junen

    2010-06-15

    The 5nm nanosilver was prepared by the sodium borohydride procedure, using sodium citrate as a stabilizing reagent. The nanosilver particle was combined with the aptamer for K(+) to form aptamer-nanosilver complex that was stabile in pH 7.0 Na(2)HPO(4)-NaH(2)PO(4) buffer solutions and in the presence of high concentration of NaCl. In 85 degrees C water bath, K(+) interacted with the aptamer to form very stable G-quadruplex that cannot stabilize the nanosilver particle. The uncombined nanosilver particles are aggregated to big particles in high concentration of NaCl, that led to the resonance scattering (RS) intensity at 470nm increased greatly. Under the selected conditions, the increased RS intensity (DeltaI) is linear to K(+) concentration in the range of 0.060-3350micromol/L, with a regression equation of DeltaI=0.177C+0.55, a correlation coefficient of 0.9964, and a detection limit of 0.006micromol/L K(+). The aptamer-nanosilver RS assay has been applied to determination of K(+) in serum and rain water, with satisfactory results.

  12. Spectral angle resolved scattering of thin film coatings.

    PubMed

    Schröder, Sven; Unglaub, David; Trost, Marcus; Cheng, Xinbin; Zhang, Jinlong; Duparré, Angela

    2014-02-01

    The light scattering of interference coatings is strongly dependent on the wavelength. In addition to the general strong increase of scattering as the wavelengths get shorter, dramatic scatter effects in and around the resonance regions can occur. This is discussed in detail for highly reflective and chirped mirrors. A new instrument is presented which enables spectral angle resolved scatter measurements of high-quality optical components to be performed between 250 and 1500 nm.

  13. Nuclear-resonant electron scattering

    NASA Astrophysics Data System (ADS)

    Pálffy, Adriana; Harman, Zoltán

    2008-04-01

    We investigate nuclear-resonant electron scattering as occurring in the two-step process of nuclear excitation by electron capture (NEEC) followed by internal conversion. The nuclear excitation and decay are treated by a phenomenological collective model in which nuclear states and transition probabilities are described by experimental parameters. We present capture rates and resonant strengths for a number of heavy-ion collision systems considering various scenarios for the resonant electron-scattering process. The results show that for certain cases resonant electron scattering can have significantly larger resonance strengths than NEEC followed by the radiative decay of the nucleus. We discuss the impact of our findings on the possible experimental observation of NEEC.

  14. 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.

  15. Controlling electromagnetic scattering with wire metamaterial resonators.

    PubMed

    Filonov, Dmitry S; Shalin, Alexander S; Iorsh, Ivan; Belov, Pavel A; Ginzburg, Pavel

    2016-10-01

    Manipulation of radiation is required for enabling a span of electromagnetic applications. Since properties of antennas and scatterers are very sensitive to the surrounding environment, macroscopic artificially created materials are good candidates for shaping their characteristics. In particular, metamaterials enable controlling both dispersion and density of electromagnetic states, available for scattering from an object. As a result, properly designed electromagnetic environments could govern wave phenomena and tailor various characteristics. Here electromagnetic properties of scattering dipoles, situated inside a wire medium (metamaterial), are analyzed both numerically and experimentally. The effect of the metamaterial geometry, dipole arrangement inside the medium, and frequency of the incident radiation on the scattering phenomena is studied in detail. It is shown that the resonance of the dipole hybridizes with Fabry-Perot modes of the metamaterial, giving rise to a complete reshaping of electromagnetic properties. Regimes of controlled scattering suppression and super-scattering are experimentally observed. Numerical analysis is in agreement with the experiment, performed at the GHz spectral range. The reported approach to scattering control with metamaterials could be directly mapped into optical and infrared spectral ranges by employing scalability properties of Maxwell's equations.

  16. Catalytic effect of ReAu nanoalloy on the Te particle reaction and its application to resonance scattering spectral assay of CA125.

    PubMed

    Cai, Wei; Liang, Aihui; Liu, Qingye; Liao, Xianjiu; Jiang, Zhiliang; Shang, Guangyi

    2011-01-01

    ReAu nanoparticles with a molar ratio of 2:8 Re and Te nanoparticles were prepared by NaBH₄ reduction. In HCl medium at 65°C, ultratrace Re, Te and ReAu bimetallic nanoparticles strongly catalyzed the slow reaction between Sn(II) and Te(VI) to form Te particles, which exhibited the strongest resonance scattering (RS) peak at 782 nm. As the amount of nanocatalyst increased, the RS intensity at 782 nm (I(782 nm) ) increased linearly, and the increase in intensity ΔI(782 nm) was linear to the ReAu, Re and Te concentrations in the ranges 0.07-9.0, 0.01-4.5 and 30-1200 nM, respectively. As a model, a ReAu immunonanoprobe catalytic Te-particle resonance scattering spectral (RSS) method was established for detection of CA125, using ReAu nanoparticle labeling CA125 antibody (CA125Ab) to obtain an immunonanoprobe (ReAuCA125Ab) for CA125. In pH 7.6 citric acid-Na₂HPO₄ buffer solution, ReAuCA125Ab aggregated nonspecifically. Upon addition of CA125, the immunonanoprobe reacted with it to form ReAuCA125Ab-CA125 dispersive immunocomplex in the solution. After the centrifugation, the supernatant containing the immunocomplex was used to catalyze the reaction of Te(VI)-Sn(II) to produce the Te particles that resulted in the I(782 nm) increasing. The ΔI(782 nm) was linear to CA125 concentration (C(CA125)) in the range 0.1-240 mU/mL. The regression equation, correlation coefficient and detection limit were ΔI(782 nm) = 1.61 C(CA125) + 1.5, 0.9978 and 0.02 mU/mL, respectively. The proposed method was applied to detect CA125 in serum samples, with satisfactory results.

  17. Theory of Fano resonance for scattering spectrum of all-dielectric spherical resonators

    NASA Astrophysics Data System (ADS)

    Koshelev, K. L.; Bogdanov, A. A.

    2017-09-01

    We provide the rigorous derivation of spectral dependence of scattering cross section for system of spherical all-dielectric nanoparticles with inhomogeneous dielectric function using resonant-state expansion. We show that in general the scattering spectrum represents a cascade of Fano resonances described by three real-valued independent parameters.

  18. A novel, simple and sensitive resonance scattering spectral method for the determination of chlorite in water by means of rhodamine B.

    PubMed

    Kang, Cai-yan; Jiang, Zhi-liang; Xi, Dan-li; He, Xing-cun

    2006-01-01

    A new resonance scattering method was proposed for the determination of chlorite, basing on the resonance scattering effect of rhodamine dye. In HCl-sodium acetate buffer solution, chlorite oxidizes I- into I2 and the reaction of I2 and excess I- results in I3- It is respectively combined with rhodamine dyes, including rhodamine B (RhB), butyl rhodamine B (b-RhB), rhodamine G (RhG) and rhodamine S (RhS), to form association complex particles, which exhibit stronger resonance scattering (RS) effect at 400 nm. The chlorite concentration of ClO2- in the range of 0.00726-0.218 microg/ml, 0.0102-0.292 microg/ml, 0.00726 0.145 microg/ml and 0.0290 0.174 microg/ml is respectively linear to the RS intensity of association complex particle systems at 400 nm for the RhB, b-RhB, RhG and RhS. The detection limits of the four systems were respectively 0.00436, 0.00652, 0.00580 and 0.01450 microg/ml ClO2-. In the four systems, the RhB system possesses good stability and high sensitivity. It has been applied to the analysis of chlorite in wastewater with satisfactory results.

  19. Resonance scattering spectral detection of catalase activity using Au@Ag nanoparticle as probe and coupling catalase catalytic reaction with Fenton reaction.

    PubMed

    Liang, Aihui; Liang, Yueyuan; Jiang, Zhiliang; Jiang, Hesheng

    2009-11-01

    The Au(core)Ag(shell) (Au@Ag) nanoparticles in size of 30 nm were prepared using 10 nm gold nanoparticles as seeds at 90 degrees C, and were purified by high-speed centrifugation to remove the excess trisodium citrate to obtain Au@Ag nanoprobe. In the medium of pH 4.0 acetate buffer solution--7.2 micromol/L H2O2--67 micromol/L Fe(II), Au@Ag nanoparticles exhibited a resonance scattering (RS) peak at 538 nm. Upon addition of Catalase (Ct), the system produced hydroxyl radical that oxidized the Au@Ag nanoprobe to form the AuAg nanoparticles with partly bare nanogold. Those AuAg nanoparticles aggregated to large nanoclusters that led to the RS peak wavelength red-shift and its RS peak intensity enhanced. The catalase activity (C) is linear to the enhanced RS intensity (DeltaI) in the range of 6 to 2,800 U/L, with regression equation of DeltaI = 0.168 C-0.2, the correlation coefficient of 0.9952, and detection limit of 2.8 U/L. This method was applied to the detection of serum samples, and the results were agreement with that of the spectrophotometry. A new catalytic mechanism of catalase was proposed with oxywater principle that was agreement with the results of resonance scattering spectroscopy, absorption spectrophotometry, transmission electron microscopy and laser scattering.

  20. Hadron scattering, resonances, and QCD

    SciTech Connect

    Briceno, Raul

    2016-12-01

    The non-perturbative nature of quantum chromodynamics (QCD) has historically left a gap in our understanding of the connection between the fundamental theory of the strong interactions and the rich structure of experimentally observed phenomena. For the simplest properties of stable hadrons, this is now circumvented with the use of lattice QCD (LQCD). In this talk I discuss a path towards a rigorous determination of few-hadron observables from LQCD. I illustrate the power of the methodology by presenting recently determined scattering amplitudes in the light-meson sector and their resonance content.

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  2. Resonance light scattering spectral method for the determination of serum albumin with the interaction of neutral red-sodium dodecyl sulfonate.

    PubMed

    Zhan, Guoqing; Zhang, Lixia; Li, Chunya

    2009-06-01

    Based on the enhancement of resonance light scattering (RLS) of serum albumin interaction with neutral red (NR) and sodium dodecyl sulfonate (SDS), a novel sensitive assay of serum albumins has been developed. Experimental conditions such as mixing sequence of reagents, pH, NR and SDS concentrations have been optimized. Linear relationships between the enhanced RLS intensity and the protein concentration were observed for bovine serum albumin (BSA) within the range of 0.01-5.0 microg mL(-1) and human serum albumin (HAS) of 0.01-7.0 microg mL(-1). The detection limits (S/N=3) are 6.0 ng mL(-1) for BSA and 5.0 ng mL(-1) for HAS, respectively. The method was successfully applied to the determination of HSA in human blood plasma samples with recovery from 97.3 to 104.3%.

  3. Resonances in pi-K scattering

    SciTech Connect

    Wilson, David J.

    2014-06-23

    We have obtained clear signals of resonances in coupled-channel pi K - eta K scattering. Using distillation and a large basis of operators we are able to extract a precise spectrum of energy levels using the variational method. These energies are analysed using inelastic extensions of the Luescher method to obtain scattering amplitudes that clearly describe S, P and D wave resonances, corresponding to the physical K_0^*(1430), the K^*(892) and the K_2^*(1430).

  4. Multimode resonant Auger scattering from the ethene molecule.

    PubMed

    Liu, Ji-Cai; Nicolas, Christophe; Sun, Yu-Ping; Flammini, Roberto; O'Keeffe, Patrick; Avaldi, Lorenzo; Morin, Paul; Kimberg, Victor; Kosugi, Nobuhiro; Gel'mukhanov, Faris; Miron, Catalin

    2011-05-12

    Resonant Auger spectra of ethene molecule have been measured with vibrational resolution at several excitation energies in the region of the C1s(-1)1b(2g)(π*) resonance. The main features observed in the experiment have been assigned and are accurately interpreted on the basis of ab initio multimode calculations. Theory explains the extended vibrational distribution of the resonant Auger spectra and its evolution as a function of the excitation energy by multimode excitation during the scattering process. As a result, the resonant Auger spectra display two qualitatively different spectral features following the Raman and non-Raman dispersion laws, respectively. Calculations show that two observed thresholds of formation of non-Raman spectral bands are related to the "double-edge" structure of the X-ray absorption spectrum.

  5. Alpha resonant scattering for astrophysical reaction studies

    SciTech Connect

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

    2014-05-02

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(α,γ) reaction, and proposed a new cluster band in {sup 11}C.

  6. Spectral shifts and spectral switches produced by scattering from a random hollow scatterer with adjustable shell thickness

    NASA Astrophysics Data System (ADS)

    Zhou, Jianyang; Zhao, Daomu

    2017-05-01

    Within the accuracy of the first-order Born approximation, the spectral shifts and spectral switches produced by the scattering of an electromagnetic light wave from a random hollow scatterer with adjustable shell thickness have been investigated. The effects of the properties of the scatterer and the incident light wave on the far-zone scattered spectrum have been discussed in detail by using numerical examples. It is shown that, as the scattering angle increases, the scattered spectrum will split into two peaks, and subsequently the two peaks will make a rapid transition as a spectral switch. The position at which the spectral switch occurs is affected by the shell thickness, the outer and inner correlation lengths of the scatterer as well as the polarization of the incident light. Besides, the polarization of the incident light also has an impact on the spectral width of the scattered field.

  7. Scattering resonances in the extreme quantum limit

    NASA Astrophysics Data System (ADS)

    Hersch, Jesse Shines

    This thesis addresses topics in low energy scattering in quantum mechanics, in particular, resonance phenomena. Hence the title: the phrase ``extreme quantum limit'' refers to the situation when the wavelengths of the particles in the system are larger than every other scale, so that the behavior is far into the quantum regime. A powerful tool in the problems of low energy scattering is the point scatterer model, and will be used extensively throughout the thesis. Therefore, we begin with a thorough introduction to this model in Chapter 2. As a first application of the point scatterer model, we will investigate the phenomenon of the proximity resonance, which is one example of strange quantum behavior appearing at low energy. Proximity resonances will be addressed theoretically in Chapter 3, and experimentally in Chapter 4. Threshold resonances, another type of low energy scattering resonance, are considered in Chapter 5, along with their connection to the Efimov and Thomas effects, and scattering in the presence of an external confining potential. Although the point scatterer model will serve us well in the work presented here, it does have its limitations. These limitations will be removed in Chapter 6, where we describe how to extend the model to include higher partial waves. In Chapter 7, we extend the model one step further, and illustrate how to treat vector wave scattering with the model. Finally, in Chapter 8 we will depart from the topic of low energy scattering and investigate the influence of diffraction on an open quantum mechanical system, again both experimentally and theoretically.

  8. Hadron scattering and resonances in QCD

    NASA Astrophysics Data System (ADS)

    Dudek, Jozef J.

    2016-05-01

    I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study ππ elastic scattering, including the ρ resonance, as well as coupled-channel π >K, ηK scattering. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.

  9. Hadron scattering and resonances in QCD

    SciTech Connect

    Dudek, Jozef J.

    2016-05-01

    I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study pi pi elastic scattering, including the rho resonance, as well as coupled-channel pi K, eta K scattering. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.

  10. Pygmy resonances probed with electron scattering

    NASA Astrophysics Data System (ADS)

    Bertulani, C. A.

    2007-05-01

    Pygmy resonances in light nuclei excited in electron scattering are discussed. These collective modes will be explored in future electron-ion colliders such as ELISe/FAIR (spokesperson: Haik Simon - GSI). Response functions for direct breakup are explored with few-body and hydrodynamical models, including the dependence upon final state interactions.

  11. Pygmy Resonances Probed with Electron Scattering

    SciTech Connect

    Bertulani, Carlos A

    2007-05-01

    Pygmy resonances in light nuclei excited in electron scattering are discussed. These collective modes will be explored in future electron-ion colliders such as ELISe/FAIR (spokesperson: Haik Simon - GSI). Response functions for direct breakup are explored with few-body and hydrodynamical models, including the dependence upon final-state interactions.

  12. Anomalous and resonance small angle scattering: Revision

    SciTech Connect

    Epperson, J.E.; Thiyagarajan, P.

    1987-11-01

    Significant changes in the small angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous dispersion terms for the scattering factor (x-rays) or scattering length (neutrons). The physics inherent in these anomalous dispersion terms is first discussed before considering how they enter the relevant scattering theory. Two major areas of anomalous scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with x-rays. However, it is pointed out that the formalism is the same for the analogue experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small angle neutron scatterings are discussed. 54 refs., 8 figs., 1 tab.

  13. Anomalous and resonance small angle scattering

    SciTech Connect

    Epperson, J.E.; Thiyagarajan, P.

    1987-11-01

    Significant changes in the small angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous dispersion terms for the scattering factor (x-rays) or scattering length (neutrons). The physics inherent in these anomalous dispersion terms is first discussed before considering how they enter the relevant scattering theory. Two major areas of anomalous scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with x-rays. However, it is pointed out that the formalism is the same or the analogue experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small-angle neutron scatterings are discussed. 8 figs.

  14. Spectral singularities and Bragg scattering in complex crystals

    SciTech Connect

    Longhi, S.

    2010-02-15

    Spectral singularities that spoil the completeness of Bloch-Floquet states may occur in non-Hermitian Hamiltonians with complex periodic potentials. Here an equivalence is established between spectral singularities in complex crystals and secularities that arise in Bragg diffraction patterns. Signatures of spectral singularities in a scattering process with wave packets are elucidated for a PT-symmetric complex crystal.

  15. Proton resonance scattering of 7Be

    SciTech Connect

    Yamaguchi, H.; Saito, A.; He, J. J.; Wakabayashi, Y.; Amadio, G.; Fujikawa, H.; Kubono, S.; Khiem, L. H.; Niikura, M.; Kwon, Y. K.; Teranishi, T.; Nishimura, S.; Togano, Y.; Iwasa, N.; Inafuku, K.

    2006-07-12

    We have studied the proton resonance scattering of 7Be by using a pure 7Be beam produced at CRIB (CNS Radioactive Ion Beam separator; CNS stands for Center of Nuclear Study, University of Tokyo). The excitation function of 8B was measured up to the excitation energy of 6.8 MeV, with the thick-target method. The excited states of 8B higher than 3.5 MeV were not known by the past experiments. This proton elastic scattering is also of importance in relation with the 7Be(p,{gamma})8B reaction, which is a key reaction in the standard solar model.

  16. Resonances in photon-photon scattering

    SciTech Connect

    Chanowitz, M.S.

    1984-11-01

    A quantity called stickiness is introduced which should be largest for J not equal to 0 glueballs and can be measured in two photon scattering and radiative J/psi decay. An argument is reviewed suggesting that light J = 0 glueballs may have large couplings to two photons. The analysis of radiative decays of eta and eta' is reviewed and a plea made to desist from false claims that they are related to GAMMA(..pi../sup 0/ ..-->.. ..gamma gamma..) by SU(3) symmetry. It is shown that two photon studies can refute the difficult-to-refute hypothesis that xi(2220) or zeta(8320) are Higgs bosons. A gallery of rogue resonances and resonance candidates is presented which would usefully be studied in ..gamma gamma.. scattering, including especially the low mass dipion. 34 references.

  17. Spectral scattering properties of turbid waters

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Poole, L. R.; Houghton, W. M.

    1980-01-01

    River water samples have been examined for optical scattering properties at wavelengths between 400 and 800 nm. Scattering coefficients were calculated from measurements of beam attenuation and absorption coefficients and are observed to vary with wavelength. At a fixed wavelength, the scattering coefficient is influenced by both phytoplankton concentration (as indicated by chlorophyll a) and suspended solids concentration. Measurements of small angle volume-scattering function indicate that the phase function at an angle of 1.5 deg is not constant for turbid waters and varies with both wavelength and beam attenuation coefficient. These data differ from previously published results for relatively clear oceanic and coastal waters. Caution is required when attempting to estimate scattering coefficient values from single-angle measurements of volume-scattering function.

  18. Spectral scattering properties of turbid waters

    NASA Technical Reports Server (NTRS)

    Whitlock, C. H.; Poole, L. R.; Houghton, W. M.

    1980-01-01

    River water samples have been examined for optical scattering properties at wavelengths between 400 and 800 nm. Scattering coefficients were calculated from measurements of beam attenuation and absorption coefficients and are observed to vary with wavelength. At a fixed wavelength, the scattering coefficient is influenced by both phytoplankton concentration (as indicated by chlorophyll a) and suspended solids concentration. Measurements of small angle volume-scattering function indicate that the phase function at an angle of 1.5 deg is not constant for turbid waters and varies with both wavelength and beam attenuation coefficient. These data differ from previously published results for relatively clear oceanic and coastal waters. Caution is required when attempting to estimate scattering coefficient values from single-angle measurements of volume-scattering function.

  19. Calculation of polarization and anisotropy of resonant and fluorescent scattering. [in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Chamberlain, Joseph W.

    1990-01-01

    Formulas are derived for the swift calculation of the angular intensity distribution and the degree of polarization associated with the resonant and fluorescent scattering of radiation by atoms which occurs in the rarefied upper atmospheres of planets during sunlit airglow phenomena. Attention is given to spectral lines with hyperfine structure, which are indicative of nuclear spin processes. The method employed involves summations over Zeeman components, allowing an evaluation of polarization through the addition of underlying simple resonant and fluorescent scattering channels.

  20. 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.

  1. Bounce resonance scattering of radiation belt electrons by H+ band EMIC waves

    NASA Astrophysics Data System (ADS)

    Cao, Xing; Ni, Binbin; Summers, Danny; Bortnik, Jacob; Tao, Xin; Shprits, Yuri Y.; Lou, Yuequn; Gu, Xudong; Fu, Song; Shi, Run; Xiang, Zheng; Wang, Qi

    2017-02-01

    We perform a detailed analysis of bounce-resonant pitch angle scattering of radiation belt electrons due to electromagnetic ion cyclotron (EMIC) waves. It is found that EMIC waves can resonate with near-equatorially mirroring electrons over a wide range of L shells and energies. H+ band EMIC waves efficiently scatter radiation belt electrons of energy >100 keV from near 90° pitch angles to lower pitch angles where the cyclotron resonance mechanism can take over to further diffuse electrons into the loss cone. Bounce-resonant electron pitch angle scattering rates show a strong dependence on L shell, wave normal angle distribution, and wave spectral properties. We find distinct quantitative differences between EMIC wave-induced bounce-resonant and cyclotron-resonant diffusion coefficients. Cyclotron-resonant electron scattering by EMIC waves has been well studied and found to be a potentially crucial electron scattering mechanism. The new investigation here demonstrates that bounce-resonant electron scattering may also be very important. We conclude that bounce resonance scattering by EMIC waves should be incorporated into future modeling efforts of radiation belt electron dynamics.

  2. Resonance effects in neutron scattering lengths

    SciTech Connect

    Lynn, J.E.

    1989-06-01

    The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-/angstrom/ wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs.

  3. Ultrafast Imaging using Spectral Resonance Modulation

    NASA Astrophysics Data System (ADS)

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-04-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera.

  4. Ultrafast Imaging using Spectral Resonance Modulation

    PubMed Central

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-01-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera. PMID:27122101

  5. Ultrafast Imaging using Spectral Resonance Modulation.

    PubMed

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-04-28

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera.

  6. Spectral dependence of fluorescence near plasmon resonant metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Yeechi

    The optical properties of fluorophores are significantly modified when placed within the near field (0--100 nm) of plasmon resonant metal nanostructures, due to the competition between increased decay rates and "hotspots" of concentrated electric fields. The decay rates and effective electric field intensities are highly dependent on the relative position of dye and metal and the overlap between plasmon resonance and dye absorption and emission. Understanding these dependencies can greatly improve the performance of biosensing and nanophotonic devices. In this dissertation, the fluorescence intensity of organic dyes and CdSe quantum dots near single metal nanoparticles is studied as a function of the local surface plasmon resonance (LSPR) of the nanoparticle. Single metal nanoparticles have narrow, well-defined, intense local surface plasmon resonances that are tunable across the visible spectrum by changes in size and shape. First, we show that organic dyes can be self-assembled on single silver nanoprisms into known configurations by the hybridization of thiolated DNA oligomers. We correlate the fluorescence intensity of the dyes to the LSPR of the individual nanoprism to which they are attached. For each of three different organic dyes, we observe a strong correlation between the fluorescence intensity of the dye and the degree of spectral overlap with the plasmon resonance of the nanoparticle. On average, we observe the brightest fluorescence from dyes attached to metal nanoparticles that have a LSPR scattering peak 40--120 meV higher in energy than the emission peak of the fluorophore. Second, the plasmon-enhanced fluorescence from CdSe/CdS/CdZnS/ZnS core/shell quantum dots is studied near a variety of silver and gold nanoparticles. With single-particle scattering spectroscopy, the localized surface plasmon resonance spectra of single metal nanoparticles is correlated with the photoluminescence excitation (PLE) spectra of the nearby quantum dots. The PLE

  7. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G. T.; Sheu, W. J.; Glass, G. A.; Wang, Y. Q.

    1999-06-10

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({gamma}=10 keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined.

  8. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G.T.; Sheu, W.J.; Glass, G.A. Wang, Y.Q.

    1999-06-01

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({Gamma}=10&hthinsp;keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined. {copyright} {ital 1999 American Institute of Physics.}

  9. 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.

  10. Scattering anomalies in a resonator above the thresholds of the continuous spectrum

    SciTech Connect

    Nazarov, S A

    2015-06-30

    We consider the Dirichlet spectral problem for the Laplace operator in a multi-dimensional domain with a cylindrical outlet to infinity, a Helmholtz resonator. Using asymptotic analysis of the scattering matrix we demonstrate different types of reflection of high-amplitude near-threshold waves. One scattering type or another, unstable or stable with respect to variations of the resonator shapes, is determined by the presence or absence of stabilizing solutions at the threshold frequency, respectively. In a waveguide with two cylindrical outlets to infinity, we discover the effect of almost complete passage of the wave under 'fine tuning' of the resonator. Bibliography: 26 titles.

  11. Physics of Cyclotron Resonance Scattering Features

    NASA Astrophysics Data System (ADS)

    Sschoenherr, Gabriele; Schwarm, Fritz-Walter; Falkner, Sebastian; Dauser, Thomas; Pottschmidt, Katja; Kretschmar, Peter; Klochkov, Dmitry; Ferrigno, Carlo; Britton Hemphill, Paul; Wilms, Joern

    2016-04-01

    Cyclotron resonant scattering features (short: cyclotron lines) are sensitive tracers of the physics of the accretion columns and mounds of X-ray pulsars. They form by interaction of X-ray photons with magnetically quantized electrons in the accreted plasma close to the neutron star. Such lines have been observed as absorption-like features for about 20 X-ray pulsars. Their energies provide a direct measure of the magnetic field strength in the line-forming region. By detailed modelling of the lines and of their parameter dependencies we can further decipher the physical conditions in the accretion column. For instance the fact that the complex scattering cross sections have a strong angle-dependence relates the phase-resolved cyclotron line shapes to parameters that constrain the systems’ still poorly understood geometry. Modelling the physics of cyclotron lines to a degree that allows for detailed and solid comparison to data therefore provides a unique access also to a better understanding of the overall picture of magnetically accreting neutron star systems.

  12. Resonant Neutron Scattering from YBa_2Cu_3O_7

    NASA Astrophysics Data System (ADS)

    Fong, Hung Fai

    1996-03-01

    Recently our ( Collaborators: B. Keimer, D. Reznik, P. Bourges, I. Aksay ) study on the 41 meV magnetic resonance in YBa_2Cu_3O7 ( H. F. Fong, B. Keimer, P. W. Anderson, D. Reznik, F. Doğan, I. A. Aksay, Phy. Rev. Lett. \\underbar 75), 316 (1995) has received considerable attention. Evidence for this mode had already been collected by other groups, but our demonstration that the resonance disappears in the normal state has stimulated a large body of theoretical work. We have extended our study in several respects, using both polarized and unpolarized neutron scattering techniques. First, by calibrating the measured magnetic intensity against calculated structure factors of optical phonons and against antiferromagnetic spin waves in the same crystal after deoxygenation to YBa_2Cu_3O_6.2, we have established the absolute scale of its dynamical susceptibility \\chi''(q,ω) in the superconducting state and a limit on its magnitude in the normal state. Second, we have measured the energy and absolute spectral weight of the resonance accurately as a function of temperature. Our experimental results will be discussed in the light of recent theoretical work. Recent measurements of the high energy spin waves in the antiferromagnetic YBa_2Cu_3O_6.2 will also be reported.

  13. Polarizability expressions for predicting resonances in plasmonic and Mie scatterers

    NASA Astrophysics Data System (ADS)

    Colom, Rémi; Devilez, Alexis; Enoch, Stefan; Stout, Brian; Bonod, Nicolas

    2017-06-01

    Polarizability expressions are commonly used in optics and photonics to model light scattering by small particles. Models based on Taylor series of the scattering coefficients of the particles fail to predict the morphologic resonances hosted by dielectric particles. Here we propose to use the factorization of the special functions appearing in the expression of the Mie scattering coefficients to derive pointlike models. These models can be applied to reproduce both Mie resonances of dielectric particles and plasmonic resonances of metallic particles. They provide simple but robust tools to predict accurately the electric and magnetic Mie resonances in dielectric particles.

  14. Coherent Raman scattering with incoherent light for a multiply resonant mixture: Theory

    NASA Astrophysics Data System (ADS)

    Kirkwood, Jason C.; Ulness, Darin J.; Stimson, Michael J.; Albrecht, A. C.

    1998-02-01

    The theory for coherent Raman scattering (CRS) with broadband incoherent light is presented for a multiply resonant, multicomponent mixture of molecules that exhibits simultaneous multiple resonances with the frequencies of the driving fields. All possible pairwise hyperpolarizability contributions to the signal intensity are included in the theoretical treatment-(resonant-resonant, resonant-nonresonant, and nonresonant-nonresonant correlations between chromophores) and it is shown how the different types of correlations manifest themselves as differently behaved components of the signal intensity. The Raman resonances are modeled as Lorentzians in the frequency domain, as is the spectral density of the incoherent light. The analytic results for this multiply resonant mixture are presented and applied to a specific binary mixture. These analytic results will be used to recover frequencies and dephasing times in a series of experiments on multiply resonant mixtures.

  15. Mie scattering as a cascade of Fano resonances.

    PubMed

    Rybin, Mikhail V; Samusev, Kirill B; Sinev, Ivan S; Semouchkin, George; Semouchkina, Elena; Kivshar, Yuri S; Limonov, Mikhail F

    2013-12-02

    We reveal that the resonant Mie scattering by high-index dielectric nanoparticles can be presented through cascades of Fano resonances. We employ the exact solution of Maxwell's equations and demonstrate that the Lorenz-Mie coefficients of the Mie problem can be expressed generically as infinite series of Fano functions as they describe interference between the background radiation originated from an incident wave and narrow-spectrum Mie scattering modes that lead to Fano resonances.

  16. Resonant scattering of surface plasmon polaritons by dressed quantum dots

    SciTech Connect

    Huang, Danhong; Cardimona, Dave; Easter, Michelle; Gumbs, Godfrey; Maradudin, A. A.; Lin, Shawn-Yu; Zhang, Xiang

    2014-06-23

    The resonant scattering of surface plasmon-polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In contrast to non-resonant scattering by a localized dielectric surface defect, a strong resonant peak in the spectrum of the scattered field is predicted that is accompanied by two side valleys. The peak height depends nonlinearly on the amplitude of SPP waves, reflecting the feedback dynamics from a photon-dressed electron-hole plasma inside the quantum dots. This unique behavior in the scattered field peak strength is correlated with the occurrence of a resonant dip in the absorption spectrum of SPP waves due to the interband photon-dressing effect. Our result on the scattering of SPP waves may be experimentally observable and applied to spatially selective illumination and imaging of individual molecules.

  17. Stroboscopic detection of nuclear resonance in an arbitrary scattering channel.

    PubMed

    Deák, L; Bottyán, L; Callens, R; Coussement, R; Major, M; Nasu, S; Serdons, I; Spiering, H; Yoda, Y

    2015-03-01

    The theory of heterodyne/stroboscopic detection of nuclear resonance scattering is developed, starting from the total scattering matrix as a product of the matrix of the reference sample and the sample under study. This general approach holds for all dynamical scattering channels. In the forward channel, which has been discussed in detail in the literature, the electronic scattering manifests itself only in an energy-independent diminution of the scattered intensity. In all other channels, complex resonance line shapes of the heterodyne/stroboscopic spectra are encountered, as a result of the interference of electronic and nuclear scattering. The grazing-incidence case will be evaluated and described in detail. Experimental data of classical X-ray reflectivity and their stroboscopically detected resonant counterpart spectra on the [(nat)Fe/(57)Fe]10 isotope periodic multilayer and antiferromagnetic [(57)Fe/Cr]20 superlattice are fitted simultaneously.

  18. Harmonic R matrices for scattering amplitudes and spectral regularization.

    PubMed

    Ferro, Livia; Łukowski, Tomasz; Meneghelli, Carlo; Plefka, Jan; Staudacher, Matthias

    2013-03-22

    Planar N = 4 supersymmetric Yang-Mills theory appears to be integrable. While this allows one to find this theory's exact spectrum, integrability has hitherto been of no direct use for scattering amplitudes. To remedy this, we deform all scattering amplitudes by a spectral parameter. The deformed tree-level four-point function turns out to be essentially the one-loop R matrix of the integrable N = 4 spin chain satisfying the Yang-Baxter equation. Deformed on-shell three-point functions yield novel three-leg R matrices satisfying bootstrap equations. Finally, we supply initial evidence that the spectral parameter might find its use as a novel symmetry-respecting regulator replacing dimensional regularization. Its physical meaning is a local deformation of particle helicity, a fact which might be useful for a much larger class of nonintegrable four-dimensional field theories.

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

    PubMed

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

    2014-02-01

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

  20. Resonant X-Ray Scattering from CeB6

    NASA Astrophysics Data System (ADS)

    Igarashi, Jun-ichi; Nagao, Tatsuya

    2002-07-01

    We calculate the resonant x-ray scattering (RXS) spectra near the Ce LIII absorption edge in CeB6, on the basis of a microscopic model that the 4f states of Ce are atomic while the 5d states form an energy band with a reasonable density of states. In the initial state, we employ an effective Hamiltonian of Shiina et al. [J. Phys. Soc. Jpn. 66 (1997) 1741] in the antiferro-quadrupole (AFQ) ordering phase, while we construct the wave function consistent with the neutron scattering experiment in the magnetic ground state. In the intermediate state, we take full account of the intra-atomic Coulomb interaction. Without assuming any lattice distortion, we obtain sufficient RXS intensities on the AFQ superlattice spot. We obtain the spectral shape, the temperature and magnetic field dependences in good agreement with the experiment, thus demonstrating the mechanism that the intensity is brought about by the modulation of 5d states through the anisotropic term of the 5d-4f Coulomb interaction. In the magnetic ground state, a small pre-edge peak is found by the E2 process. On the magnetic superlattice spot, we get a finite but considerably small intensity. The magnetic form factor is briefly discussed.

  1. Laser multi-spectral polarimetric diffuse-scatter imaging

    NASA Astrophysics Data System (ADS)

    Wang, Yang

    Laser multi-spectral polarimetric diffuse scatter (LAMPODS) imaging is an approach that maps an object intrinsic optical scattering properties rather than the scattered light intensity like in conventional imaging. The technique involves comprehensive measurements of the object scattering response function that is to be parameterized with respect to wavelength, polarization, and angular scattering distribution. The LAMPODS images are mappings of the derived parameters, which are more fundamental than conventional images. The LAMPODS imaging system was built based on a system architecture design configured similarly to an optical wireless network that allows multiple communication connections simultaneously among any number of transmitters and receivers. The imaging system was implemented into several sets of experimental apparatuses that can detect Stokes vectors of backward and forward scattered light with laser sources at seven near infrared (NIR) wavelengths and a continuous mid-infrared (mid-IR) spectral range for both macroscopic and microscopic scan imaging applications. The system components, such as transmitters, receivers, image scan unit, and the data acquisition module, were built and/or tested to match the system-design requirements, which involved many optical, opto-mechanical, electronic, and computer programming/interfacing techniques and skills. The experiments performed include the study on the LAMPODS capability with isolated aspects of scattering response, and the test of LAMPODS on uncontrolled subjects. With special-made targets, the results indicate that the LAMPODS system can distinguish consistently the four produced random surface roughnesses, regardless of the subjects? Spectroscopic signature, and can separate the spectroscopic features independently. Various natural and man-made targets were tested to challenge the LAMPODS system capability and found many interesting features regarding spectral response, polarimetric response, and

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  3. Resonant Compton Scattering of Photons by Helium Atoms in Lorentzian Astrophysical Plasmas

    NASA Astrophysics Data System (ADS)

    Kar, Sabyasachi; Wang, Yang; Ho, Y. K.; Jiang, Zishi

    2016-12-01

    We investigate the effects of Lorentzian astrophysical plasmas on resonant Compton scattering of photons by the helium ground and excited states. The bound-excited states energies in the plasma environments are obtained by using highly correlated exponential wave functions in the framework of Ritz variational method. The resonance Compton scattering cross sections in Lorentzian plasmas between the 1s2{ }1S and 1s2p 1P, 1s2s 1S and 1s3p 1P, 1s3s 1S and 1s3d 1D states are reported as a function of the spectral index and plasma parameter. The nonthermal character of the Lorentzian plasmas shows interesting features on the resonant Compton scattering cross sections.

  4. [Analysis of spectral intensity of fermi resonance of molecules].

    PubMed

    Jiang, Yong-heng; Gao, Shu-qin; Li, Zhan-long; Cao, Biao; Li, Zuo-wei

    2010-01-01

    Raman spectra of liquid carbon disulfide (CS) and carbon tetrachloride (CCl4) were measured. And the spectral intensity was analyzed using the J. F. Bertran theory and the group theory. The rule about Fermi resonance was obtained from the Raman spectra of carbon disulfide (CS) and carbon tetrachloride (CCL4): (1) The energy can transfer between a fundamental and an overtone frequency about Fermi resonance; the two spectra have the same intensity. The spectral intensity of the two spectra was equal (R=1) about Fermi resonance, when the difference between fundamental of Fermi resonance and overtone of Fermi resonance was very small. (2) The intensity of overtone is stronger than that of fundamental's. (3) The spectrum of Fermi resonance was observed, but the fundamental frequency was not. This article has very good reference value for the assignments in the molecular structure and the research of contents.

  5. Spectral density in the resonance region and analytic confinement

    SciTech Connect

    Kalloniatis, Alex C.; Nedelko, Sergei N.; Smekal, Lorenz von

    2004-11-01

    We study the role of finite widths of resonances in a nonlocal version of the Wick-Cutkosky model. The spectrum of bound states is known analytically in this model and forms linear Regge tragectories. We compute the widths of resonances, calculate the spectral density in an extension of the Breit-Wigner ansatz and discuss a mechanism for the damping of unphysical exponential growth of observables at high energy due to finite widths of resonances.

  6. Further study of spectral ripple with a laser scattering measurement apparatus

    NASA Astrophysics Data System (ADS)

    Tan, Zhongqi; Luo, Zhifu; Liu, Siqi; Zhang, Xiaobao; Long, Xingwu

    2017-06-01

    To study the spectral effect further, which exists in fold-type cavity ring-down or enhanced absorption spectrometer, a set of laser scattering measurement apparatus was presented and applied to evaluate the surface status of high-reflectivity coatings. Based on this apparatus and another set of optical-feedback cavity ring-down spectrometer with the equivalent noise absorption coefficient of 9.0×10-9 cm-1, some experiments are carried out to inspect some analyses about the effect's mechanism. It is determined that the spectral ripple originates from the interference fringe's movement of resonance light beams along the surface of folding mirror, which causes the folding mirror's loss to change with the laser wavelength's scanning. Based on this conclusion, the potential application and the processing methods of spectral ripple are proposed and discussed.

  7. Resonant Compton Scattering in Highly-Magnetized Pulsars

    NASA Astrophysics Data System (ADS)

    Wadiasingh, Zorawar

    Soft gamma repeaters and anomalous X-ray pulsars are subset of slow-rotating neutron stars, known as magnetars, that have extremely high inferred surface magnetic fields, of the order 100-1000 TeraGauss. Hard, non-thermal and pulsed persistent X-ray emission extending between 10 keV and 230 keV has been seen in a number of magnetars by RXTE, INTEGRAL, and Suzaku. In this thesis, the author considers inner magnetospheric models of such persistent hard X-ray emission where resonant Compton upscattering of soft thermal photons is anticipated to be the most efficient radiative process. This high efficiency is due to the relative proximity of the surface thermal photons, and also because the scattering becomes resonant at the cyclotron frequency. At the cyclotron resonance, the effective cross section exceeds the classical Thomson one by over two orders of magnitude, thereby enhancing the efficiency of continuum production and cooling of relativistic electrons. In this thesis, a new Sokolov and Ternov formulation of the QED Compton scattering cross section for strong magnetic fields is employed in electron cooling and emission spectra calculations. This formalism is formally correct for treating spin-dependent effects and decay rates that are important at the cyclotron resonance. The author presents electron cooling rates at arbitrary interaction points in a magnetosphere using the QED cross sections. The QED effects reduce the rates below high-field extrapolations of older magnetic Thomson results. The author also computes angle-dependent upscattering model spectra, formed using collisional integrals, for uncooled monoenergetic relativistic electrons injected in inner regions of pulsar magnetospheres. These spectra are integrated over closed field lines and obtained for different observing perspectives. The spectral cut-off energies are critically dependent on the observer viewing angles and electron Lorentz factor. It is found that electrons with energies less than

  8. Resonant Scattering of Surface Plasmon Polaritons by Dressed Quantum Dots

    DTIC Science & Technology

    2014-06-23

    Resonant scattering of surface plasmon polaritons by dressed quantum dots Danhong Huang,1 Michelle Easter,2 Godfrey Gumbs,3 A. A. Maradudin,4 Shawn... polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In con- trast to...induced polarization field, treated as a source term9 arising from photo-excited electrons, allows for a resonant scattering of surface plasmon- polariton

  9. Strong WW scattering chiral lagrangians, unitarity and resonances

    SciTech Connect

    Pelaez, J.R.

    1996-08-01

    Chiral lagrangians provide a model independent description of the strongly interacting symmetry breaking sector. In this work, first we review the LHC sensitivity to the chiral parameters (in the hardest case of non-resonant low-energy WW scattering). Later we show how to reproduce or predict the resonance spectrum by means of dispersion theory and the inverse amplitude method. We present a parameter space scan that covers many different strong WW scattering scenarios.

  10. Pais approximation for slow scattered and resonant particles

    SciTech Connect

    Bruk, Yu. M. Voloshchuk, A. N.

    2016-08-15

    A method for the calculation of the partial scattering phases for particles with nonzero angular momenta and for effectively short-range potentials has been discussed. Solutions to the Pais equations for slow particles have been constructed. The inverse problem of the determination of a relation between the parameters of potentials and energies of scattered particles in the resonance situation has been considered.

  11. Resonant unidirectional and elastic scattering of surface plasmon polaritons by high refractive index dielectric nanoparticles

    NASA Astrophysics Data System (ADS)

    Evlyukhin, Andrey B.; Bozhevolnyi, Sergey I.

    2015-12-01

    We consider scattering of surface plasmon polaritons (SPPs) and light by individual high refractive index dielectric nanoparticles (NPs) located on a metal (gold) substrate and supporting electric and magnetic dipole resonances in the visible spectral range. Numerical calculations are carried out by making use of the discrete dipole approximation including the multipole decomposition procedure. Extinction and scattering cross-section spectra of spheroid silicon NPs in visible and near infrared are presented and discussed. The roles of the in-plane and out-of-plane components of electric and magnetic dipoles in the scattering processes are clarified and demonstrated. It is revealed that, owing to the NP interaction with electromagnetic fields reflected from the substrate (that leads to bianisotropy), the in-plane electric and magnetic dipoles can resonantly be excited at the same wavelength. Due to this effect, the resonant unidirectional (forward) and elastic (in-plane) scattering of SPPs by oblate spheroid NPs can be realized within a narrow spectral range. In the case of normal light incidence, the bianisotropy effect can provide significant suppression of the SPP excitation because of the destructive interference between the SPP waves generated by induced electric and magnetic dipole moments. The results obtained open new possibilities for the development of SPP-based photonic components and metasurfaces, whose operation involves resonant excitations of dielectric NPs.

  12. Resonance scattering by fish schools: A comparison of two models.

    PubMed

    Raveau, M; Feuillade, C

    2016-01-01

    The effective medium method is used to investigate resonance scattering from schools of fish with gas-filled swim bladders, as a function of frequency and azimuth. Calculations are also performed with a coupled differential equation model, which incorporates both multiple scattering between fish and wave interference interactions of their scattered fields [Feuillade, Nero, and Love, J. Acoust. Soc. Am. 99, 196-208 (1996)]. A theoretical comparison of the models for idealized spherical schools shows good agreement over the entire resonance region in the forward direction, where interference interactions have a minimal effect. Good agreement is also seen in back scattering at low frequencies, where the wavelength λ≥4s, and s is the average nearest neighbor fish separation. If λ<4s, the models diverge in back scattering, and the effective medium method fails. This can be critically important when migrations of schools to deeper water cause the collective resonance frequency to increase. Multiple scattering interactions are negligible when |4πnf(b)(2)/k|⪅0.01, where n is the fish number density, f(b) is the individual fish scattering amplitude, and k=2π/λ. A comparison with forward scattering data shows very good agreement for both models, and indicates a method for estimating fish abundance. For back scattering data, the effective medium method diverges strongly when λ<4s.

  13. The κ resonance in s wave πK scatterings

    NASA Astrophysics Data System (ADS)

    Zheng, H. Q.; Zhou, Z. Y.; Qin, G. Y.; Xiao, Z. G.; Wang, J. J.; Wu, N.

    2004-03-01

    A new unitarization approach incorporated with chiral symmetry is established and applied to study the πK elastic scatterings. We demonstrate that the κ resonance exists, if the scattering length parameter in the I=1/2, J=0 channel does not deviate much from its value predicted by chiral perturbation theory. The mass and width of the κ resonance is found to be Mκ=594±79 MeV, Γκ=724±332 MeV, obtained by fitting the LASS data up to 1430 MeV. Better determination to the pole parameters is possible if the chiral predictions on scattering lengths are taken into account.

  14. Low-Intensity Nonlinear Spectral Effects in Compton Scattering

    SciTech Connect

    Hartemann, F V; Albert, F; Siders, C W; Barty, C P

    2010-02-23

    Nonlinear effects are known to occur in Compton scattering light sources, when the laser normalized 4-potential, A = e{radical}-A{sub {mu}}A{sup {mu}}/m{sub 0}c approaches unity. In this letter, it is shown that nonlinear spectral features can appear at arbitrarily low values of A, if the fractional bandwidth of the laser pulse, {Delta}{phi}{sup -1}, is sufficiently small to satisfy A{sup 2} {Delta}{phi} {approx_equal} 1. A three dimensional analysis, based on a local plane-wave, slow-varying envelope approximation, enables the study of these effects for realistic interactions between an electron beam and a laser pulse, and their influence on high-precision Compton scattering light sources.

  15. Aircraft Engine Noise Scattering - A Discontinuous Spectral Element Approach

    NASA Technical Reports Server (NTRS)

    Stanescu, D.; Hussaini, M. Y.; Farassat, F.

    2002-01-01

    The paper presents a time-domain method for computation of sound radiation from aircraft engine sources to the far-field. The effects of nonuniform flow around the aircraft and scattering of sound by fuselage and wings are accounted for in the formulation. Our approach is based on the discretization of the inviscid flow equations through a collocation form of the Discontinuous Galerkin spectral element method. An isoparametric representation of the underlying geometry is used in order to take full advantage of the spectral accuracy of the method. Largescale computations are made possible by a parallel implementation based on message passing. Results obtained for radiation from an axisymmetric nacelle alone are compared with those obtained when the same nacelle is installed in a generic con.guration, with and without a wing.

  16. Anisotropic Elastic Resonance Scattering model for the Neutron Transport equation

    SciTech Connect

    Mohamed Ouisloumen; Abderrafi M. Ougouag; Shadi Z. Ghrayeb

    2014-11-24

    The resonance scattering transfer cross-section has been reformulated to account for anisotropic scattering in the center-of-mass of the neutron-nucleus system. The main innovation over previous implementations is the relaxation of the ubiquitous assumption of isotropic scattering in the center-of-mass and the actual effective use of scattering angle distributions from evaluated nuclear data files in the computation of the angular moments of the resonant scattering kernels. The formulas for the high order anisotropic moments in the laboratory system are also derived. A multi-group numerical formulation is derived and implemented into a module incorporated within the NJOY nuclear data processing code. An ultra-fine energy mesh cross section library was generated using these new theoretical models and then was used for fuel assembly calculations with the PARAGON lattice physics code. The results obtained indicate a strong effect of this new model on reactivity, multi-group fluxes and isotopic inventory during depletion.

  17. Resonant soft X-ray scattering for polymer materials

    DOE PAGES

    Liu, Feng; Brady, Michael A.; Wang, Cheng

    2016-04-16

    Resonant Soft X-ray Scattering (RSoXS) was developed within the last few years, and the first dedicated resonant soft X-ray scattering beamline for soft materials was constructed at the Advanced Light Source, LBNL. RSoXS combines soft X-ray spectroscopy with X-ray scattering and thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Using RSoXS to characterize multi-length scale soft materials with heterogeneous chemical structures, we have demonstrated that soft X-ray scattering is a unique complementary technique to conventional hard X-ray and neutron scattering. Its unique chemical sensitivity, large accessible size scale, molecular bondmore » orientation sensitivity with polarized X-rays, and high coherence have shown great potential for chemically specific structural characterization for many classes of materials.« less

  18. Resonant soft X-ray scattering for polymer materials

    SciTech Connect

    Liu, Feng; Brady, Michael A.; Wang, Cheng

    2016-04-16

    Resonant Soft X-ray Scattering (RSoXS) was developed within the last few years, and the first dedicated resonant soft X-ray scattering beamline for soft materials was constructed at the Advanced Light Source, LBNL. RSoXS combines soft X-ray spectroscopy with X-ray scattering and thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Using RSoXS to characterize multi-length scale soft materials with heterogeneous chemical structures, we have demonstrated that soft X-ray scattering is a unique complementary technique to conventional hard X-ray and neutron scattering. Its unique chemical sensitivity, large accessible size scale, molecular bond orientation sensitivity with polarized X-rays, and high coherence have shown great potential for chemically specific structural characterization for many classes of materials.

  19. Tailoring dielectric resonator geometries for directional scattering and Huygens’ metasurfaces

    DOE PAGES

    Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; ...

    2015-01-28

    In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity dielectric cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometrymore » in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole resonances to achieve local behavior. These properties are confirmed through the multipolar expansion and show that the use of geometries suggested by perturbation theory is a viable route to achieve purely dipole resonances for metamaterial applications such as wave-front manipulation with Huygens’ metasurfaces. Our results are fully scalable across any frequency bands where high-permittivity dielectric materials are available, including microwave, THz, and infrared frequencies.« less

  20. Tailoring dielectric resonator geometries for directional scattering and Huygens’ metasurfaces

    SciTech Connect

    Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; Sinclair, Michael B.

    2015-01-28

    In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity dielectric cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometry in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole resonances to achieve local behavior. These properties are confirmed through the multipolar expansion and show that the use of geometries suggested by perturbation theory is a viable route to achieve purely dipole resonances for metamaterial applications such as wave-front manipulation with Huygens’ metasurfaces. Our results are fully scalable across any frequency bands where high-permittivity dielectric materials are available, including microwave, THz, and infrared frequencies.

  1. Spectral singularity in composite systems and simulation of a resonant lasing cavity

    NASA Astrophysics Data System (ADS)

    Zhang, X. Z.; Li, G. R.; Song, Z.

    2017-10-01

    We investigate herein the existence of spectral singularities (SSs) in composite systems that consist of two separate scattering centers A and B embedded in one-dimensional free space, with at least one scattering center being non-Hermitian. We show that such composite systems have an SS at kc if the reflection amplitudes rA≤ft(kc\\right) and rB≤ft(kc\\right) of the two scattering centers satisfy the condition rR A≤ft(kc\\right) rLB≤ft(kc\\right) ei2kc≤ft(xB-xA\\right) =1 . We also extend the condition to the system with multi-scattering centers. As an application, we construct a simple system to simulate a resonant lasing cavity.

  2. Dephasing and resonance electronic Raman scattering

    NASA Astrophysics Data System (ADS)

    Koningstein, J. A.

    1988-05-01

    The intensity of the resonance electronic Raman spectrum of terbium aluminum garnet is discussed in terms of radiative, non-radiative and pure electronic dephasing processes which govern the width of the resonating excited electronic state. As a result of fast electronic dephasing in comparison to the other processes, the enhancement of the intensity of the electronic Raman band of the terbium ion is suppressed.

  3. Scattering and coupling between subwavelength resonators

    NASA Astrophysics Data System (ADS)

    Karami, Morteza; Kitchin, Steven; Fiddy, M. A.

    2014-09-01

    We examine the coupling between resonances of closely spaced meta-atoms and investigate the role of extended effective periodicities of clusters of subwavelength sized elements on the overall bulk properties. The possibilities of negative refraction both with and without negative index, as well as the role of strong coupling near resonance on effective medium models and homogenization close to the photonic crystal limit are presented.

  4. Biochemical component identification by light scattering techniques in whispering gallery mode optical resonance based sensor

    NASA Astrophysics Data System (ADS)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Saetchnikov, Anton V.; Schweiger, Gustav; Ostendorf, Andreas

    2014-03-01

    Experimental data on detection and identification of variety of biochemical agents, such as proteins (albumin, interferon, C reactive protein), microelements (Na+, Ca+), antibiotic of different generations, in both single and multi component solutions under varied in wide range concentration are represented. Analysis has been performed on the light scattering parameters of whispering gallery mode (WGM) optical resonance based sensor with dielectric microspheres from glass and PMMA as sensitive elements fixed by spin - coating techniques in adhesive layer on the surface of substrate or directly on the coupling element. Sensitive layer was integrated into developed fluidic cell with a digital syringe. Light from tuneable laser strict focusing on and scattered by the single microsphere was detected by a CMOS camera. The image was filtered for noise reduction and integrated on two coordinates for evaluation of integrated energy of a measured signal. As the entrance data following signal parameters were used: relative (to a free spectral range) spectral shift of frequency of WGM optical resonance in microsphere and relative efficiency of WGM excitation obtained within a free spectral range which depended on both type and concentration of investigated agents. Multiplexing on parameters and components has been realized using spatial and spectral parameters of scattered by microsphere light with developed data processing. Biochemical component classification and identification of agents under investigation has been performed by network analysis techniques based on probabilistic network and multilayer perceptron. Developed approach is demonstrated to be applicable both for single agent and for multi component biochemical analysis.

  5. The spectral shift between near- and far-field resonances of optical nano-antennas.

    PubMed

    Menzel, Christoph; Hebestreit, Erik; Mühlig, Stefan; Rockstuhl, Carsten; Burger, Sven; Lederer, Falk; Pertsch, Thomas

    2014-04-21

    Within the past several years a tremendous progress regarding optical nano-antennas could be witnessed. It is one purpose of optical nano-antennas to resonantly enhance light-matter interactions at the nanoscale, e.g. the interaction of an external illumination with molecules. In this specific, but in almost all schemes that take advantage of resonantly enhanced electromagnetic fields in the vicinity of nano-antennas, the precise knowledge of the spectral position of resonances is of paramount importance to fully exploit their beneficial effects. Thus far, however, many nano-antennas were only optimized with respect to their far-field characteristics, i.e. in terms of their scattering or extinction cross sections. Although being an emerging feature in many numerical simulations, it was only recently fully appreciated that there exists a subtle but very important difference in the spectral position of resonances in the near-and the far-field. With the purpose to quantify this shift, Zuloaga et al. suggested a Lorentzian model to estimate the resonance shift. Here, we devise on fully analytical grounds a strategy to predict the resonance in the near-field directly from that in the far-field and disclose that the issue is involved and multifaceted, in general. We outline the limitations of our theory if more sophisticated optical nano-antennas are considered where higher order multipolar contributions and higher order antenna resonances become increasingly important. Both aspects are highlighted by numerically studying relevant nano-antennas.

  6. Resonant Scattering of X-ray Emission Lines in the Hot Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Churazov, Eugene; Zhuravleva, Irina; Sazonov, Sergey; Sunyaev, Rashid

    2010-12-01

    While very often a hot intergalactic medium (IGM) is optically thin to continuum radiation, the optical depth in resonant lines can be of order unity or larger. Resonant scattering in the brightest X-ray emission lines can cause distortions in the surface brightness distribution, spurious variations in the abundance of heavy elements, changes in line spectral shapes and even polarization of line emission. The magnitude of these effects not only depends on the density, temperature and ionization state of the gas, but is also sensitive to the characteristics of the gas velocity field. This opens a possibility to use resonant scattering as a convenient and powerful tool to study IGM properties. We discuss the application of these effects to galaxy clusters.

  7. Resonant soft X-ray scattering on protein solutions

    NASA Astrophysics Data System (ADS)

    Ye, Dan; Le, Thinh; Wang, Cheng; Zwart, Peter; Gomez, Esther; Gomez, Enrique

    Protein structure is crucial for biological function, such that characterizing protein folding and packing is important for the design of therapeutics and enzymes. We propose resonant soft X-ray scattering (RSOXS) as an approach to study proteins and other biological assemblies in solution. Calculations of the scattering contrast suggest that soft X-ray scattering is more sensitive than hard X-ray scattering, because of contrast generated at the absorption edges of constituent elements such as carbon, nitrogen and oxygen. We have examined the structure of bovine serum albumin (BSA) in solution by RSOXS. We find that by varying incident X-ray energies, we are able to achieve higher scattering contrast near the absorption edge. From our RSOXS scattering result we are able to reconstruct the structure of BSA in 3D. These RSOXS results also agree with hard X-ray experiments, including crystallographic data. Our study demonstrates the potential of RSOXS for studying protein structure in solution.

  8. Spectral separation of optical spin based on antisymmetric Fano resonances

    PubMed Central

    Piao, Xianji; Yu, Sunkyu; Hong, Jiho; Park, Namkyoo

    2015-01-01

    We propose a route to the spectral separation of optical spin angular momentum based on spin-dependent Fano resonances with antisymmetric spectral profiles. By developing a spin-form coupled mode theory for chiral materials, the origin of antisymmetric Fano spectra is clarified in terms of the opposite temporal phase shift for each spin, which is the result of counter-rotating spin eigenvectors. An analytical expression of a spin-density Fano parameter is derived to enable quantitative analysis of the Fano-induced spin separation in the spectral domain. As an application, we demonstrate optical spin switching utilizing the extreme spectral sensitivity of the spin-density reversal. Our result paves a path toward the conservative spectral separation of spins without any need of the magneto-optical effect or circular dichroism, achieving excellent purity in spin density superior to conventional approaches based on circular dichroism. PMID:26561372

  9. Dissociation of chloromethanes upon resonant σ{sup *} excitation studied by x-ray scattering

    SciTech Connect

    Bohinc, R.; Bučar, K.; Kavčič, M.; Žitnik, M.; Journel, L.; Guillemin, R.; Marchenko, T.; Simon, M.; Cao, W.

    2013-10-07

    The dissociation process following the Cl K-shell excitation to σ{sup *} resonances is studied by high resolution spectroscopy of resonant elastic and inelastic x-ray scattering on CH{sub 3}Cl, CH{sub 2}Cl{sub 2}, CHCl{sub 3}, and CCl{sub 4} molecules. Calculations employing the transition potential and Delta-Kohn-Sham DFT approach are in good agreement with the measured total fluorescence yield and show the presence of a second quasidegenerate group of states with σ{sup *} character above the lowest σ{sup *} unoccupied molecular orbital for molecules with more than one Cl atom. A bandwidth narrowing and a nonlinear dispersion behavior is extracted from the Kα spectral maps for both σ{sup *} resonances. The fitted data indicate that the widths of the Franck-Condon distributions for the first and second σ{sup *} resonances are comparable for all the molecules under study. In addition, an asymmetric broadening of the emission peaks is observed for resonant elastic x-ray scattering with zero detuning on both σ{sup *} resonances. This is attributed to the fast dissociation, transferring about 0.15 of the scattering probability into higher vibrational modes.

  10. E- and F- region incoherent scatter radar spectral measurements at mid and low-latitudes

    NASA Astrophysics Data System (ADS)

    Kudeki, Erhan; Milla, Marco

    2016-07-01

    In this talk we will contrast and compare incoherent scatter radar spectral measurements conducted using the Arecibo, ALTAIR, and Jicamarca incoherent scatter radars at ionospheric heights ranging from E-region into the topside F-region. Arecibo measurements from mid-latitudes exemplify high SNR ISR techniques utilized with large magnetic aspect angles. Low-latitude measurements at ALTAIR and Jicamarca make use of and combine large and small magnetic aspect angle techniques. Examples presented will include both natural and naturally enhanced electron and ion lines detected in the lower F region near the geomagnetic equator as well as the results of search for proton gyro-resonance peaks in the Jicamarca topside spectra.

  11. Chiral dynamics in form factors, spectral-function sum rules, meson-meson scattering and semilocal duality

    NASA Astrophysics Data System (ADS)

    Guo, Zhi-Hui; Oller, J. A.; de Elvira, J. Ruiz

    2012-09-01

    In this work, we perform the one-loop calculation of the scalar and pseudoscalar form factors in the framework of U(3) chiral perturbation theory with explicit tree level exchanges of resonances. The meson-meson scattering calculation from Guo and Oller [Phys. Rev. DPRVDAQ1550-7998 84, 034005 (2011)10.1103/PhysRevD.84.034005] is extended as well. The spectral functions of the nonet scalar-scalar (SS) and pseudoscalar-pseudoscalar (PP) correlators are constructed by using the corresponding form factors. After fitting the unknown parameters to the scattering data, we discuss the resonance content of the resulting scattering amplitudes. We also study spectral-function sum rules in the SS-SS, PP-PP, and SS-PP sectors as well as semilocal duality from scattering. The former relate the scalar and pseudoscalar spectra between themselves while the latter mainly connects the scalar spectrum with the vector one. Finally we investigate these items as a function of NC for NC>3. All these results pose strong constraints on the scalar dynamics and spectroscopy that are discussed. They are successfully fulfilled by our meson-meson scattering amplitudes and spectral functions.

  12. A fiber-laser-based stimulated Raman scattering spectral microscope

    NASA Astrophysics Data System (ADS)

    Nose, Keisuke; Ozeki, Yasuyuki; Kishi, Tatsuya; Sumimura, Kazuhiko; Kanematsu, Yasuo; Itoh, Kazuyoshi

    2013-02-01

    Stimulated Raman scattering (SRS) spectral microscopy is a powerful technique for label-free biological imaging because it allows us to distinguish chemical species with overlapping Raman bands. Here we present an SRS spectral microscope based only on fiber lasers (FL's), which offer the possibilities of downsizing and simplification of the system. A femtosecond figure-8 Er-FL at a repetition rate of 54.4 MHz is used to generate pump pulses. After amplified by an Er doped fiber amplifier, Er-FL pulses are spectrally compressed to 2-ps second harmonic pulses. For generating Stokes pulses, a femtosecond Yb-FL pulses at a repetition rate of 27.2 MHz is used. Then these lasers are synchronized by a phase locked loop, which consists of a two-photon absorption photodetector, a loop filter, a phase modulator in the Er- FL cavity, and a piezo electric transducer in the Yb-FL cavity. The intensity noise of pump pulses is reduced by the collinear balanced detection (CBD) technique based on delay-and-add fiber lines. Experimentally, we confirmed that the intensity noise level of probe pulses was close to the shot noise limit. The Stokes pulses are introduced to a wavelength tunable band pass filter (BPF), which consists of a galvanomirror scanner, a 4-f optical system, a reflection grating, and a collimator. This system is able to scan the wavenumber from 2850 cm-1 to 3100 cm-1 by tuning the BPF. We succeeded in the spectral imaging of a mixture of polystyrene beads and poly(methyl methacrylate) beads.

  13. Direct observation of resonance scattering patterns in single silicon nanoparticles

    NASA Astrophysics Data System (ADS)

    Valuckas, Vytautas; Paniagua-Domínguez, Ramón; Fu, Yuan Hsing; Luk'yanchuk, Boris; Kuznetsov, Arseniy I.

    2017-02-01

    We present the first direct observation of the scattering patterns of electric and magnetic dipole resonances excited in a single silicon nanosphere. Almost perfectly spherical silicon nanoparticles were fabricated and deposited on a 30 nm-thick silicon nitride membrane in an attempt to minimize particle—substrate interaction. Measurements were carried out at visible wavelengths by means of the Fourier microscopy in a dark-field illumination setup. The obtained back-focal plane images clearly reveal the characteristic scattering patterns associated with each resonance and are found to be in a good agreement with the simulated results.

  14. Effect of scattering on the resonant tunneling diode current

    NASA Astrophysics Data System (ADS)

    Sinkkonen, J.

    A simple semiclassical model is presented for the vertical transport in the multibarrier structures. Fitting rules for the distribution functions at different sides of the barrier are constructed in such a way that they also take into account the correlation between the incoming electron waves. This correlation is essential for the quantum interference phenomena. An approximation for the correlation function is obtained by assuming an exponential damping by scattering of the coherent part of the electron wave function. The model is applied for the resonant tunneling diode. The resulting expression for the dc-current includes scattering damped resonant transmission.

  15. Compton scattering off proton in the third resonance region

    NASA Astrophysics Data System (ADS)

    Cao, Xu; Lenske, H.

    2017-09-01

    Compton scattering off the proton in the third resonance region is analyzed for the first time, owing to the full combined analysis of pion- and photo-induced reactions in a coupled-channel effective Lagrangian model with K-matrix approximation. Two isospin I = 3 / 2 resonances D33 (1700) and F35 (1930) are found to be essential in the range of 1.6-1.8 GeV. The recent beam asymmetry data of Compton scattering from the GRAAL facility are used to determine the helicity couplings of these resonances, and strong constraints are coming also from πN and KΣ photoproduction data. The possible spin and parity of new narrow resonances is discussed.

  16. Investigating the absolute phase information in acoustic wave resonance scattering

    PubMed Central

    Mitri, F.G.; Greenleaf, J.F.; Fellah, Z.E.A.; Fatemi, M.

    2014-01-01

    The aim if this work is to investigate the absolute phase information in resonance acoustic scattering by spheres and cylinders and place this work in the broader context of scattering in which the properties of the magnitude and (processed) phase have been examined in a more general way than in the classical Resonance Scattering Theory (RST). Here, comparisons are made between the classical and modified RST formalisms of acoustic resonance scattering. Experimental and theoretical backscattering form functions are obtained and discussed. It is shown that the magnitude and processed (unwrapped) phase can be correctly obtained through the classical RST, suggesting that the modified RST formalism offers little new practical advantage. Furthermore, the absolute phase is shown to be very sensitive to object's resonances, suggesting that the unwrapped phase may be considered as an efficient tool, along with the magnitude information, to carry out remote (active) classification of targets in underwater acoustics applications. The combination of absolute phase information with the magnitude data offers a complementary advantage in the identification of resonances from cylinders and spheres. PMID:18294670

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

    PubMed

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

    2013-03-01

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

  18. Resonances in low-energy positron-alkali scattering

    NASA Technical Reports Server (NTRS)

    Horbatsch, M.; Ward, S. J.; Mceachran, R. P.; Stauffer, A. D.

    1990-01-01

    Close-coupling calculations were performed with up to five target states at energies in the excitation threshold region for positron scattering from Li, Na and K. Resonances were discovered in the L = 0, 1 and 2 channels in the vicinity of the atomic excitation thresholds. The widths of these resonances vary between 0.2 and 130 MeV. Evidence was found for the existence of positron-alkali bound states in all cases.

  19. Transition representations of quantum evolution with application to scattering resonances

    SciTech Connect

    Strauss, Y.

    2011-03-15

    A Lyapunov operator is a self-adjoint quantum observable whose expectation value varies monotonically as time increases and may serve as a marker for the flow of time in a quantum system. In this paper it is shown that the existence of a certain type of Lyapunov operator leads to representations of the quantum dynamics, termed transition representations, in which an evolving quantum state {psi}(t) is decomposed into a sum {psi}(t) ={psi}{sup b}(t) +{psi}{sup f}(t) of a backward asymptotic component and a forward asymptotic component such that the evolution process is represented as a transition from {psi}{sup b}(t) to {psi}{sup f}(t). When applied to the evolution of scattering resonances, such transition representations separate the process of decay of a scattering resonance from the evolution of outgoing waves corresponding to the probability 'released' by the resonance and carried away to spatial infinity. This separation property clearly exhibits the spatial probability distribution profile of a resonance. Moreover, it leads to the definition of exact resonance states as elements of the physical Hilbert space corresponding to the scattering problem. These resonance states evolve naturally according to a semigroup law of evolution.

  20. Polarization of photons scattered by electrons in any spectral distribution

    SciTech Connect

    Chang, Zhe; Lin, Hai-Nan; Jiang, Yunguo

    2014-01-01

    On the basis of the quantum electrodynamics, we present a generic formalism of the polarization for beamed monochromatic photons scattered by electrons in any spectral distribution. The formulae reduce to the components of the Fano matrix when electrons are at rest. We mainly investigate the polarization in three scenarios, i.e., electrons at rest, isotropic electrons with a power-law spectrum, and thermal electrons. If the incident beam is polarized, the polarization is reduced significantly by isotropic electrons at large viewing angles; the degree of polarization caused by thermal electrons is about half of that caused by power-law electrons. If the incident bean is unpolarized, soft γ-rays can lead to about 15% polarization at viewing angles around π/4. For isotropic electrons, one remarkable feature is that the polarization as a function of the incident photon energy always peaks roughly at 1 MeV; this is valid for both the thermal and power-law cases. This feature can be used to distinguish the model of the inverse Compton scattering from that of the synchrotron radiation.

  1. A spectrally accurate algorithm for electromagnetic scattering in three dimensions

    NASA Astrophysics Data System (ADS)

    Ganesh, M.; Hawkins, S.

    2006-09-01

    In this work we develop, implement and analyze a high-order spectrally accurate algorithm for computation of the echo area, and monostatic and bistatic radar cross-section (RCS) of a three dimensional perfectly conducting obstacle through simulation of the time-harmonic electromagnetic waves scattered by the conductor. Our scheme is based on a modified boundary integral formulation (of the Maxwell equations) that is tolerant to basis functions that are not tangential on the conductor surface. We test our algorithm with extensive computational experiments using a variety of three dimensional perfect conductors described in spherical coordinates, including benchmark radar targets such as the metallic NASA almond and ogive. The monostatic RCS measurements for non-convex conductors require hundreds of incident waves (boundary conditions). We demonstrate that the monostatic RCS of small (to medium) sized conductors can be computed using over one thousand incident waves within a few minutes (to a few hours) of CPU time. We compare our results with those obtained using method of moments based industrial standard three dimensional electromagnetic codes CARLOS, CICERO, FE-IE, FERM, and FISC. Finally, we prove the spectrally accurate convergence of our algorithm for computing the surface current, far-field, and RCS values of a class of conductors described globally in spherical coordinates.

  2. Possible resonance in positron-lithium scattering

    NASA Astrophysics Data System (ADS)

    Abdel-Raouf, M. A.; Wood, R. F.

    1990-09-01

    The possible appearance of resonances in the partial cross sections of the inelastic collisions of positrons with lithium atoms at energies below 5 eV is investigated. It is assumed that only elastic and rearrangement channels are open, while excitation channels are closed. A coupled static formalism, in which the polarization potentials of the lithium and positronium are switched on, is employed. The basis set of Clementi and Roetti [At. Data Nucl. Data Tables 14, 177 (1974)] is used for describing the target model. Comparison between the resulting total cross sections and those obtained by other authors is presented.

  3. Fano resonance between Mie and Bragg scattering in photonic crystals.

    PubMed

    Rybin, M V; Khanikaev, A B; Inoue, M; Samusev, K B; Steel, M J; Yushin, G; Limonov, M F

    2009-07-10

    We report the observation of a Fano resonance between continuum Mie scattering and a narrow Bragg band in synthetic opal photonic crystals. The resonance leads to a transmission spectrum exhibiting a Bragg dip with an asymmetric profile, which can be tunably reversed to a Bragg rise. The Fano asymmetry parameter is linked with the dielectric contrast between the permittivity of the filler and the specific value determined by the opal matrix. The existence of the Fano resonance is directly related to disorder due to nonuniformity of a-SiO2 opal spheres. The theoretical "quasi-3D" model produces results in excellent agreement with the experimental data.

  4. Raman Scattering at Resonant or Near-Resonant Conditions: A Generalized Short-Time Approximation

    NASA Astrophysics Data System (ADS)

    Mohammed, Abdelsalam; Sun, Yu-Ping; Miao, Quan; Ågren, Hans; Gel'mukhanov, Faris

    2012-02-01

    We investigate the dynamics of resonant Raman scattering in the course of the frequency detuning. The dephasing in the time domain makes the scattering fast when the photon energy is tuned from the absorption resonance. This makes frequency detuning to act as a camera shutter with a regulated scattering duration and provides a practical tool of controlling the scattering time in ordinary stationary measurements. The theory is applied to resonant Raman spectra of a couple of few-mode model systems and to trans-1,3,5-hexatriene and guanine-cytosine (G-C) Watson-Crick base pairs (DNA) molecules. Besides some particular physical effects, the regime of fast scattering leads to a simplification of the spectrum as well as to the scattering theory itself. Strong overtones appear in the Raman spectra when the photon frequency is tuned in the resonant region, while in the mode of fast scattering, the overtones are gradually quenched when the photon frequency is tuned more than one vibrational quantum below the first absorption resonance. The detuning from the resonant region thus leads to a strong purification of the Raman spectrum from the contamination by higher overtones and soft modes and purifies the spectrum also in terms of avoidance of dissociation and interfering fluorescence decay of the resonant state. This makes frequency detuning a very useful practical tool in the analysis of the resonant Raman spectra of complex systems and considerably improves the prospects for using the Raman effect for detection of foreign substances at ultra-low concentrations.

  5. Plasmonic piezoelectric nanomechanical resonator for spectrally selective infrared sensing

    NASA Astrophysics Data System (ADS)

    Hui, Yu; Gomez-Diaz, Juan Sebastian; Qian, Zhenyun; Alù, Andrea; Rinaldi, Matteo

    2016-04-01

    Ultrathin plasmonic metasurfaces have proven their ability to control and manipulate light at unprecedented levels, leading to exciting optical functionalities and applications. Although to date metasurfaces have mainly been investigated from an electromagnetic perspective, their ultrathin nature may also provide novel and useful mechanical properties. Here we propose a thin piezoelectric plasmonic metasurface forming the resonant body of a nanomechanical resonator with simultaneously tailored optical and electromechanical properties. We experimentally demonstrate that it is possible to achieve high thermomechanical coupling between electromagnetic and mechanical resonances in a single ultrathin piezoelectric nanoplate. The combination of nanoplasmonic and piezoelectric resonances allows the proposed device to selectively detect long-wavelength infrared radiation with unprecedented electromechanical performance and thermal capabilities. These attributes lead to the demonstration of a fast, high-resolution, uncooled infrared detector with ~80% absorption for an optimized spectral bandwidth centered around 8.8 μm.

  6. Plasmonic piezoelectric nanomechanical resonator for spectrally selective infrared sensing.

    PubMed

    Hui, Yu; Gomez-Diaz, Juan Sebastian; Qian, Zhenyun; Alù, Andrea; Rinaldi, Matteo

    2016-04-15

    Ultrathin plasmonic metasurfaces have proven their ability to control and manipulate light at unprecedented levels, leading to exciting optical functionalities and applications. Although to date metasurfaces have mainly been investigated from an electromagnetic perspective, their ultrathin nature may also provide novel and useful mechanical properties. Here we propose a thin piezoelectric plasmonic metasurface forming the resonant body of a nanomechanical resonator with simultaneously tailored optical and electromechanical properties. We experimentally demonstrate that it is possible to achieve high thermomechanical coupling between electromagnetic and mechanical resonances in a single ultrathin piezoelectric nanoplate. The combination of nanoplasmonic and piezoelectric resonances allows the proposed device to selectively detect long-wavelength infrared radiation with unprecedented electromechanical performance and thermal capabilities. These attributes lead to the demonstration of a fast, high-resolution, uncooled infrared detector with ∼80% absorption for an optimized spectral bandwidth centered around 8.8 μm.

  7. Plasmonic piezoelectric nanomechanical resonator for spectrally selective infrared sensing

    PubMed Central

    Hui, Yu; Gomez-Diaz, Juan Sebastian; Qian, Zhenyun; Alù, Andrea; Rinaldi, Matteo

    2016-01-01

    Ultrathin plasmonic metasurfaces have proven their ability to control and manipulate light at unprecedented levels, leading to exciting optical functionalities and applications. Although to date metasurfaces have mainly been investigated from an electromagnetic perspective, their ultrathin nature may also provide novel and useful mechanical properties. Here we propose a thin piezoelectric plasmonic metasurface forming the resonant body of a nanomechanical resonator with simultaneously tailored optical and electromechanical properties. We experimentally demonstrate that it is possible to achieve high thermomechanical coupling between electromagnetic and mechanical resonances in a single ultrathin piezoelectric nanoplate. The combination of nanoplasmonic and piezoelectric resonances allows the proposed device to selectively detect long-wavelength infrared radiation with unprecedented electromechanical performance and thermal capabilities. These attributes lead to the demonstration of a fast, high-resolution, uncooled infrared detector with ∼80% absorption for an optimized spectral bandwidth centered around 8.8 μm. PMID:27080018

  8. Location and Characterization of Underwater Ordnance using Resonance Scattered Sonar

    NASA Astrophysics Data System (ADS)

    Gritto, R.; Korneev, V. A.

    2009-12-01

    Unexploded ordnance (UXO) present a worldwide hazard in locations of previous military confrontations and at military training facilities. In particular, the presence of unexploded ordinance in coastal regions poses a severe risk that must be addressed before sites can be turned over to the public or coastal areas made available for commercial traffic. Although progress has been made in detecting UXO in underwater areas, there still exists a need for technologies that can detect and locate UXO buried in seafloor sediments and reliably distinguish munitions from clutter. We are investigating a method based on resonance scattering using small data sets in a controlled pond environment. The use of resonance scattering allows for deeper bottom penetration than in the case of the generally used acoustic imaging, because in the former case the wavelengths are longer than the latter. Furthermore, in the resonance scattering regime the geometry is independent of the target orientation. The sonar data sets were acquired during 2006 and 2007 by the Applied Physics Laboratory, University of Washington, at the Surface Warfare Center, Panama City, FL, and included an aluminum cylinder and sphere, as well as artillery shells and mortar rounds buried in the sandy pond bottom. Our results show that resonance scattered waves, although smaller in amplitude than the specular reflected signal, dominate much of the recorded traces in time. These signals can be used to determine the propagation velocities in the pond sediments, to locate the UXO in the subsurface and to characterize the UXO type by its size and filler velocities.

  9. Nuclear resonant scattering beamline at the Advanced Photon Source

    SciTech Connect

    Alp, E.E.; Mooney, T.M.; Toellner, T.; Sturhahn, W.

    1993-09-01

    The principal and engineering aspects of a dedicated synchrotron radiation beamline under construction at the Advanced Photon Source for nuclear resonant scattering purposes are explained. The expected performance in terms of isotopes to be studied, flux, and timing properties is discussed.

  10. Resonant Raman scattering from silicon nanoparticles enhanced by magnetic response

    NASA Astrophysics Data System (ADS)

    Dmitriev, Pavel A.; Baranov, Denis G.; Milichko, Valentin A.; Makarov, Sergey V.; Mukhin, Ivan S.; Samusev, Anton K.; Krasnok, Alexander E.; Belov, Pavel A.; Kivshar, Yuri S.

    2016-05-01

    Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07965a

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

    PubMed

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

    2015-08-01

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

  12. Optically resonant magneto-electric cubic nanoantennas for ultra-directional light scattering

    NASA Astrophysics Data System (ADS)

    Sikdar, Debabrata; Cheng, Wenlong; Premaratne, Malin

    2015-02-01

    Cubic dielectric nanoparticles are promising candidates for futuristic low-loss, ultra-compact, nanophotonic applications owing to their larger optical coefficients, greater packing density, and relative ease of fabrication as compared to spherical nanoparticles; besides possessing negligible heating at nanoscale in contrast to their metallic counterparts. Here, we present the first theoretical demonstration of azimuthally symmetric, ultra-directional Kerker's-type scattering of simple dielectric nanocubes in visible and near-infrared regions via simultaneous excitation and interference of optically induced electric- and magnetic-resonances up to quadrupolar modes. Unidirectional forward-scattering by individual nanocubes is observed at the first generalized-Kerker's condition for backward-scattering suppression, having equal electric- and magnetic-dipolar responses. Both directionality and magnitude of these unidirectional-scattering patterns get enhanced where matching electric- and magnetic-quadrupolar responses spectrally overlap. While preserving azimuthal-symmetry and backscattering suppression, a nanocube homodimer provides further directionality improvement for increasing interparticle gap, but with reduced main-lobe magnitude due to emergence of side-scattering lobes from diffraction-grating effect. We thoroughly investigate the influence of interparticle gap on scattering patterns and propose optimal range of gap for minimizing side-scattering lobes. Besides suppressing undesired side-lobes, significant enhancement in scattering magnitude and directionality is attained with increasing number of nanocubes forming a linear chain. Optimal directionality, i.e., the narrowest main-scattering lobe, is found at the wavelength of interfering quadrupolar resonances; whereas the largest main-lobe magnitude is observed at the wavelength satisfying the first Kerker's condition. These unique optical properties of dielectric nanocubes thus can revolutionize their

  13. Optically resonant magneto-electric cubic nanoantennas for ultra-directional light scattering

    SciTech Connect

    Sikdar, Debabrata Premaratne, Malin; Cheng, Wenlong

    2015-02-28

    Cubic dielectric nanoparticles are promising candidates for futuristic low-loss, ultra-compact, nanophotonic applications owing to their larger optical coefficients, greater packing density, and relative ease of fabrication as compared to spherical nanoparticles; besides possessing negligible heating at nanoscale in contrast to their metallic counterparts. Here, we present the first theoretical demonstration of azimuthally symmetric, ultra-directional Kerker's-type scattering of simple dielectric nanocubes in visible and near-infrared regions via simultaneous excitation and interference of optically induced electric- and magnetic-resonances up to quadrupolar modes. Unidirectional forward-scattering by individual nanocubes is observed at the first generalized-Kerker's condition for backward-scattering suppression, having equal electric- and magnetic-dipolar responses. Both directionality and magnitude of these unidirectional-scattering patterns get enhanced where matching electric- and magnetic-quadrupolar responses spectrally overlap. While preserving azimuthal-symmetry and backscattering suppression, a nanocube homodimer provides further directionality improvement for increasing interparticle gap, but with reduced main-lobe magnitude due to emergence of side-scattering lobes from diffraction-grating effect. We thoroughly investigate the influence of interparticle gap on scattering patterns and propose optimal range of gap for minimizing side-scattering lobes. Besides suppressing undesired side-lobes, significant enhancement in scattering magnitude and directionality is attained with increasing number of nanocubes forming a linear chain. Optimal directionality, i.e., the narrowest main-scattering lobe, is found at the wavelength of interfering quadrupolar resonances; whereas the largest main-lobe magnitude is observed at the wavelength satisfying the first Kerker's condition. These unique optical properties of dielectric nanocubes thus can revolutionize their

  14. Spectral singularity in composite systems and simulation of laser resonant chamber

    NASA Astrophysics Data System (ADS)

    Zhang, Xizheng

    A non-Hermitian system with spectral singularity (SS) exhibits fascinating phenomena which never appear in a Hermitian system. We investigate the existence of SS for a composite system which is consisted of two separated scattering centers A and B embedded in a one-dimensional free space, one of which is non-Hermitian at last. We show that the composite system has a SS at kc if the reflection amplitudes rAkc and rBkc of two scattering centers satisfy the condition rRAkcrLBkce i 2kcxB -xA = 1 , based on the theorem proposed by Ali (PRL 102, 220402 (2009). Multi-scattering-centers generalization of the theorem is also obtained. As an application, we construct a simple system to simulate the resonant chamber for generating laser light. Spectral singularity in composite systems and simulation of laser resonant chamber.

  15. Quark models of dibaryon resonances in nucleon-nucleon scattering

    SciTech Connect

    Ping, J. L.; Huang, H. X.; Pang, H. R.; Wang Fan; Wong, C. W.

    2009-02-15

    We look for {delta}{delta} and N{delta} resonances by calculating NN scattering phase shifts of two interacting baryon clusters of quarks with explicit coupling to these dibaryon channels. Two phenomenological nonrelativistic chiral quark models giving similar low-energy NN properties are found to give significantly different dibaryon resonance structures. In the chiral quark model (ChQM), the dibaryon system does not resonate in the NNS waves, in agreement with the experimental SP07 NN partial-wave scattering amplitudes. In the quark delocalization and color screening model (QDCSM), the S-wave NN resonances disappear when the nucleon size b falls below 0.53 fm. Both quark models give an IJ{sup P}=03{sup +}{delta}{delta} resonance. At b=0.52 fm, the value favored by the baryon spectrum, the resonance mass is 2390 (2420) MeV for the ChQM with quadratic (linear) confinement, and 2360 MeV for the QDCSM. Accessible from the {sup 3}D{sub 3}{sup NN} channel, this resonance is a promising candidate for the known isoscalar ABC structure seen more clearly in the pn{yields}d{pi}{pi} production cross section at 2410 MeV in the recent preliminary data reported by the CELSIUS-WASA Collaboration. In the isovector dibaryon sector, our quark models give a bound or almost bound {sup 5}S{sub 2}{sup {delta}}{sup {delta}} state that can give rise to a {sup 1}D{sub 2}{sup NN} resonance. None of the quark models used have bound N{delta}P states that might generate odd-parity resonances.

  16. PT -symmetric spectral singularity and negative-frequency resonance

    NASA Astrophysics Data System (ADS)

    Pendharker, Sarang; Guo, Yu; Khosravi, Farhad; Jacob, Zubin

    2017-03-01

    Vacuum consists of a bath of balanced and symmetric positive- and negative-frequency fluctuations. Media in relative motion or accelerated observers can break this symmetry and preferentially amplify negative-frequency modes as in quantum Cherenkov radiation and Unruh radiation. Here, we show the existence of a universal negative-frequency-momentum mirror symmetry in the relativistic Lorentzian transformation for electromagnetic waves. We show the connection of our discovered symmetry to parity-time (PT ) symmetry in moving media and the resulting spectral singularity in vacuum fluctuation-related effects. We prove that this spectral singularity can occur in the case of two metallic plates in relative motion interacting through positive- and negative-frequency plasmonic fluctuations (negative-frequency resonance). Our work paves the way for understanding the role of PT -symmetric spectral singularities in amplifying fluctuations and motivates the search for PT symmetry in novel photonic systems.

  17. Resonant magnetic scattering of polarized soft x rays

    SciTech Connect

    Sacchi, M.; Hague, C.F.; Gullikson, E.M.; Underwood, J.

    1997-04-01

    Magnetic effects on X-ray scattering (Bragg diffraction, specular reflectivity or diffuse scattering) are a well known phenomenon, and they also represent a powerful tool for investigating magnetic materials since it was shown that they are strongly enhanced when the photon energy is tuned across an absorption edge (resonant process). The resonant enhancement of the magnetic scattering has mainly been investigated at high photon energies, in order to match the Bragg law for the typical lattice spacings of crystals. In the soft X-ray range, even larger effects are expected, working for instance at the 2p edges of transition metals of the first row or at the 3d edges of rare earths (300-1500 eV), but the corresponding long wavelengths prevent the use of single crystals. Two approaches have been recently adopted in this energy range: (i) the study of the Bragg diffraction from artificial structures of appropriate 2d spacing; (ii) the analysis of the specular reflectivity, which contains analogous information but has no constraints related to the lattice spacing. Both approaches have their own specific advantages: for instance, working under Bragg conditions provides information about the (magnetic) periodicity in ordered structures, while resonant reflectivity can easily be related to electronic properties and absorption spectra. An important aspect common to all the resonant X-ray scattering techniques is the element selectivity inherent to the fact of working at a specific absorption edge: under these conditions, X-ray scattering becomes in fact a spectroscopy. Results are presented for films of iron and cobalt.

  18. Homogenization of an ensemble of interacting resonant scatterers

    NASA Astrophysics Data System (ADS)

    Schilder, N. J.; Sauvan, C.; Sortais, Y. R. P.; Browaeys, A.; Greffet, J.-J.

    2017-07-01

    We study theoretically the concept of homogenization in optics using an ensemble of randomly distributed resonant stationary atoms with density ρ . The ensemble is dense enough for the usual condition for homogenization, viz. ρ λ3≫1 , to be reached. Introducing the coherent and incoherent scattered powers, we define two criteria to define the homogenization regime. We find that when the excitation field is tuned in a broad frequency range around the resonance, neither of the criteria for homogenization is fulfilled, meaning that the condition ρ λ3≫1 is not sufficient to characterize the homogenized regime around the atomic resonance. We interpret these results as a consequence of the light-induced dipole-dipole interactions between the atoms, which implies a description of scattering in terms of collective modes rather than as a sequence of individual scattering events. Finally, we show that, although homogenization can never be reached for a dense ensemble of randomly positioned laser-cooled atoms around resonance, it becomes possible if one introduces spatial correlations in the positions of the atoms or nonradiative losses, such as would be the case for organic molecules or quantum dots coupled to a phonon bath.

  19. Resonant Soft X-ray Scattering for Soft Materials

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Young, Athony; Hexemer, Alexander; Padmore, Howard

    2015-03-01

    Over the past a few years, we have developed Resonant Soft X-ray Scattering (RSoXS) and constructed the first dedicated resonant soft x-ray scattering beamline at the Advanced Light Source, LBNL. RSoXS combines soft x-ray spectroscopy with x-ray scattering thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Its unique chemical sensitivity, large accessible size scale, molecular bond orientation sensitivity with polarized x-rays and high coherence have shown great potential for chemical/morphological structure characterization for many classes of materials. Some recent development of in-situ soft x-ray scattering with in-vacuum sample environment will be discussed. In order to study sciences in naturally occurring conditions, we need to overcome the sample limitations set by the low penetration depth of soft x-rays and requirement of high vacuum. Adapting to the evolving environmental cell designs utilized increasingly in the Electron Microscopy community, customized designed liquid/gas environmental cells will enable soft x-ray scattering experiments on biological, electro-chemical, self-assembly, and hierarchical functional systems in both static and dynamic fashion. Recent RSoXS results on organic electronics, block copolymer thin films, and membrane structure will be presented.

  20. Collisionless Spectral Kinetic Simulation of Ideal Multipole Resonance Probe

    NASA Astrophysics Data System (ADS)

    Gong, Junbo; Wilczek, Sebastian; Szeremley, Daniel; Oberrath, Jens; Eremin, Denis; Dobrygin, Wladislaw; Schilling, Christian; Friedrichs, Michael; Brinkmann, Ralf Peter

    2016-09-01

    Active Plasma Resonance Spectroscopy denotes a class of industry-compatible plasma diagnostic methods which utilize the natural ability of plasmas to resonate on or near the electron plasma frequency ωpe. One particular realization of APRS with a high degree of geometric and electric symmetry is the Multipole Resonance Probe (MRP). The Ideal MRP(IMRP) is an even more symmetric idealization which is suited for theoretical investigations. In this work, a spectral kinetic scheme is presented to investigate the behavior of the IMRP in the low pressure regime. However, due to the velocity difference, electrons are treated as particles whereas ions are only considered as stationary background. In the scheme, the particle pusher integrates the equations of motion for the studied particles, the Poisson solver determines the electric field at each particle position. The proposed method overcomes the limitation of the cold plasma model and covers kinetic effects like collisionless damping.

  1. Resonant scattering and diffraction beamline P09 at PETRA III.

    PubMed

    Strempfer, J; Francoual, S; Reuther, D; Shukla, D K; Skaugen, A; Schulte-Schrepping, H; Kracht, T; Franz, H

    2013-07-01

    The resonant scattering and diffraction beamline P09 at PETRA III is designed for X-ray experiments requiring small beams, energy tunability, variable polarization and high photon flux. It is highly flexible in terms of beam size and offers full higher harmonic suppression. A state-of-the-art double phase-retarder set-up provides variable linear or circular polarization. A high-precision Psi-diffractometer and a heavy-load diffractometer in horizontal Psi-geometry allow the accommodation of a wide variety of sample environments. A 14 T cryo-magnet is available for scattering experiments in magnetic fields.

  2. Resonance electronic Raman scattering in rare earth crystals

    SciTech Connect

    Williams, G.M.

    1988-11-10

    The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce/sup 3 +/(4f/sup 1/) in single crystals of LuPO/sub 4/ and Er/sup 3 +/(4f/sup 11/) in single crystals of ErPO/sub 4/. 134 refs., 92 figs., 33 tabs.

  3. Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering

    PubMed Central

    Ferrari, Eugenio; Spezzani, Carlo; Fortuna, Franck; Delaunay, Renaud; Vidal, Franck; Nikolov, Ivaylo; Cinquegrana, Paolo; Diviacco, Bruno; Gauthier, David; Penco, Giuseppe; Ribič, Primož Rebernik; Roussel, Eleonore; Trovò, Marco; Moussy, Jean-Baptiste; Pincelli, Tommaso; Lounis, Lounès; Manfredda, Michele; Pedersoli, Emanuele; Capotondi, Flavio; Svetina, Cristian; Mahne, Nicola; Zangrando, Marco; Raimondi, Lorenzo; Demidovich, Alexander; Giannessi, Luca; De Ninno, Giovanni; Danailov, Miltcho Boyanov; Allaria, Enrico; Sacchi, Maurizio

    2016-01-01

    The advent of free-electron laser (FEL) sources delivering two synchronized pulses of different wavelengths (or colours) has made available a whole range of novel pump–probe experiments. This communication describes a major step forward using a new configuration of the FERMI FEL-seeded source to deliver two pulses with different wavelengths, each tunable independently over a broad spectral range with adjustable time delay. The FEL scheme makes use of two seed laser beams of different wavelengths and of a split radiator section to generate two extreme ultraviolet pulses from distinct portions of the same electron bunch. The tunability range of this new two-colour source meets the requirements of double-resonant FEL pump/FEL probe time-resolved studies. We demonstrate its performance in a proof-of-principle magnetic scattering experiment in Fe–Ni compounds, by tuning the FEL wavelengths to the Fe and Ni 3p resonances. PMID:26757813

  4. Spectral phase-shift detection of surface plasmon resonance

    NASA Astrophysics Data System (ADS)

    Duliakova, M.; Hlubina, P.; Ciprian, D.

    2016-12-01

    A two-step spectral interferometric technique to detect the spectral phase shift of surface plasmon resonance (SPR) in the Kretschmann configuration is proposed and demonstrated. The technique utilizes a polarimetry setup to record two channeled spectra, one including reflection of p- and s-polarized waves from an SPR structure for air when the SPR phenomenon does not occur, and the other one for an analyte when the SPR phenomenon occurs. The channeled spectra are used to detect the SPR spectral phase shift and first, an SF10 glass prism and a gold coated SF10 slide with a chromium adhesion layer is used to measure the SPR phase shift for aqueous solutions of ethanol. In addition, the position of a sharp maximum in the spectral derivative of the SPR phase shift is measured as a function of the analyte parameter. Second, the setup with a gold coated SF10 glass prism is used to measure the SPR phase shift for the same analyte. It is revealed that the detection accuracy of the measurement of the spectral derivative of the SPR phase shift in the second setup is lower than that in the first setup. For the first case, the measurements are accompanied by theoretical modeling of the SPR responses using the material dispersion characteristics.

  5. RESONANT INELASTIC X-RAY SCATTERING FROM TRANSITION METAL OXIDES.

    SciTech Connect

    HILL,J.P.

    1999-08-23

    Recent developments in hard x-ray resonant inelastic x-ray scattering as a probe of strongly correlated systems are reviewed. Particular attention is paid to studies of Nd{sub 2}CuO{sub 4}. A charge transfer excitation is observed when the incident photon energy is tuned in the vicinity of the copper K-edge. It is shown that the presence of resonant enhancements is controlled by the polarization dependence of the excitation process and by the overlap between a given intermediate state and the particular excitation being studied. This latter observation has shed light on the non-local effects present in certain intermediate states.

  6. Diffusion and Criticality in Undoped Graphene with Resonant Scatterers

    NASA Astrophysics Data System (ADS)

    Ostrovsky, P. M.; Titov, M.; Bera, S.; Gornyi, I. V.; Mirlin, A. D.

    2010-12-01

    A general theory is developed to describe graphene with an arbitrary number of isolated impurities. The theory provides a basis for an efficient numerical analysis of the charge transport and is applied to calculate the Dirac-point conductivity σ of graphene with resonant scatterers. In the case of smooth resonant impurities the symmetry class is identified as DIII and σ grows logarithmically with increasing impurity concentration. For vacancies (or strong on-site potential impurities, class BDI) σ saturates at a constant value that depends on the vacancy distribution among two sublattices.

  7. Resonant enhancement of Raman scattering in metamaterials with hybrid electromagnetic and plasmonic resonances

    NASA Astrophysics Data System (ADS)

    Guddala, Sriram; Narayana Rao, D.; Ramakrishna, S. Anantha

    2016-06-01

    A tri-layer metamaterial perfect absorber of light, consisting of (Al/ZnS/Al) films with the top aluminum layer patterned as an array of circular disk nanoantennas, is investigated for resonantly enhancing Raman scattering from C60 fullerene molecules deposited on the metamaterial. The metamaterial is designed to have resonant bands due to plasmonic and electromagnetic resonances at the Raman pump frequency (725 nm) as well as Stokes emission bands. The Raman scattering from C60 on the metamaterial with resonantly matched bands is measured to be enhanced by an order of magnitude more than C60 on metamaterials with off-resonant absorption bands peaking at 1090 nm. The Raman pump is significantly enhanced due to the resonance with a propagating surface plasmon band, while the highly impedance-matched electromagnetic resonance is expected to couple out the Raman emission efficiently. The nature and hybridization of the plasmonic and electromagnetic resonances to form compound resonances are investigated by numerical simulations.

  8. Electron scattering in HCl: An improved nonlocal resonance model

    NASA Astrophysics Data System (ADS)

    Fedor, J.; Winstead, C.; McKoy, V.; Čížek, M.; Houfek, K.; Kolorenč, P.; Horáček, J.

    2010-04-01

    We present an improved nonlocal resonance model for electron-HCl collisions. The short-range part of the model is fitted to ab initio electron-scattering eigenphase sums calculated using the Schwinger multichannel method, while the long-range part is based on the ab initio potential-energy curve of the bound anion HCl-. This model significantly improves the agreement of nonlocal resonance calculations with recent absolute experimental data on dissociative electron attachment cross sections for HCl and DCl. It also partly resolves an inconsistency in the temperature effect in dissociative electron attachment to HCl present in the literature. Finally, the present model reproduces all qualitative structures observed previously in elastic scattering and vibrational-excitation cross sections.

  9. Far-field superresolution by imaging of resonance scattering

    NASA Astrophysics Data System (ADS)

    Schuster, Gerard T.; Huang, Yunsong

    2014-12-01

    We show that superresolution imaging in the far-field region of the sources and receivers is theoretically and practically possible if migration of resonant multiples is employed. A resonant multiple is one that bounces back and forth between two scattering points; it can also be the multiple between two smoothly varying interfaces as long as the reflection wave paths partially overlap and reflect from the same Fresnel zone. For a source with frequency f, compared to a one-way trip, N round trips in propagating between two scatterers increase the effective frequency by 2N × f and decrease the effective wavelength by λ/(2N). Thus, multiples can, in principle, be used as high-frequency probes to estimate detailed properties of layers. Tests with both synthetic and field data validate this claim. Improved resolution by multiple imaging is not only feasible for crustal reflections, but might be applicable to mantle and core reverberations recorded by earthquake seismologists.

  10. 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.

  11. scattering and D meson resonances from lattice QCD

    NASA Astrophysics Data System (ADS)

    Mohler, Daniel; Prelovsek, Sasa; Woloshyn, R. M.

    2013-02-01

    A first exploratory lattice QCD simulation is presented, aimed at extracting the masses and widths of the broad scalar D0*(2400) and the axial D1(2430) charm-light resonances. For that purpose Dπ and D*π scattering are simulated, and the resonance parameters are extracted using a Breit-Wigner fit of the resulting phase shifts. We use a single two-flavor dynamical ensemble with mπ≈266MeV, a≃0.124fm and a rather small volume V=163×32. The resulting D0*(2400) mass is 351±21MeV above the spin average (1)/(4)(mD+3mD*), in agreement with the experimental value of 347±29MeV above. The resulting D0*→Dπ coupling, glat=2.55±0.21GeV, is close to the experimental value gexp⁡≤1.92±0.14GeV, where g parametrizes the width Γ≡g2p*/s. The resonance parameters for the broad D1(2430) are also found close to the experimental values; these are obtained by appealing to the heavy quark limit, where the neighboring resonance D1(2420) is narrow. The calculated I=1/2 scattering lengths are a0=0.81±0.14fm for Dπ and a0=0.81±0.17fm for D*π scattering. The simulation of the scattering in these channels incorporates quark-antiquark as well as multihadron interpolators, and the distillation method is used for contractions. In addition, the ground and several excited charm-light and charmonium states with various JP are calculated using standard quark-antiquark interpolators.

  12. Enhanced charge excitations in electron-doped cuprates by resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Tohyama, Takami; Tsutsui, Kenji; Mori, Michiyasu; Sota, Shigetoshi; Yunoki, Seiji

    2015-07-01

    Resonant inelastic x-ray scattering (RIXS) tuned for the Cu L edge is a possible tool to detect charge excitations in cuprate superconductors. We theoretically investigate the possibility for observing a collective charge excitation by the RIXS. The RIXS process via the intermediate state inevitably makes the spectral weight of charge excitation stronger in electron doping than in hole doping. Electron-hole asymmetry also appears in the dynamical charge structure factor, showing a new enhanced small-momentum low-energy mode in electron doping. These facts indicate a possibility of detecting the new charge mode by RIXS in electron-doped systems.

  13. Resonant inelastic x-ray scattering at the limit of subfemtosecond natural lifetime

    SciTech Connect

    Marchenko, T.; Journel, L.; Marin, T.; Guillemin, R.; Carniato, S.; Simon, M.; Zitnik, M.; Kavcic, M.; Bucar, K.; Mihelic, A.; Hoszowska, J.; Cao, W.

    2011-04-14

    We present measurements of the resonant inelastic x-ray scattering (RIXS) spectra of the CH{sub 3}I molecule in the hard-x-ray region near the iodine L{sub 2} and L{sub 3} absorption edges. We show that dispersive RIXS spectral features that were recognized as a fingerprint of dissociative molecular states can be interpreted in terms of ultrashort natural lifetime of {approx}200 attoseconds in the case of the iodine L-shell core-hole. Our results demonstrate the capacity of the RIXS technique to reveal subtle dynamical effects in molecules with sensitivity to nuclear rearrangement on a subfemtosecond time scale.

  14. Resonant raman scattering in complexes of nc-Si/SiO2 quantum dots and oligonucleotides

    NASA Astrophysics Data System (ADS)

    Bairamov, F. B.; Poloskin, E. D.; Kornev, A. A.; Chernev, A. L.; Toporov, V. V.; Dubina, M. V.; Röder, C.; Sprung, C.; Lipsanen, H.; Bairamov, B. Kh.

    2014-11-01

    We report on the functionalization of nanocrystalline nc-Si/SiO2 semiconductor quantum dots (QDs) by short d(20G, 20T) oligonucleotides. The obtained complexes have been studied by Raman spectroscopy techniques with high spectral and spatial resolution. A new phenomenon of multiband resonant light scattering on single oligonucleotide molecules has been discovered, and peculiarities of this effect related to the nonradiative transfer of photoexcitation from nc-Si/SiO2 quantum dots to d(20G, 20T) oligonucleotide molecules have been revealed.

  15. Surface-enhanced Raman scattering on nanoshells with tunable surface plasmon resonance.

    PubMed

    Alvarez-Puebla, Ramon A; Ross, Daniel J; Nazri, G-Abbas; Aroca, Ricardo F

    2005-11-08

    Fabrication, characterization, and optical enhancement applications of bimetallic AgAu nanoparticles and nanoshells are reported. Nanoparticles with tunable surface plasmon resonances are synthesized at room temperature and characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and photon correlation spectroscopy. The collective electron oscillation of the nanoparticles shows a controllable tunability in the 400-990 nm spectral range, in agreement with plasmon absorption calculated using Mie theory, providing an optimum substrate for surface plasmon-assisted enhanced spectroscopy. Surface-enhanced Raman scattering experiments show that the average enhancement factor obtained with nanoshells could be higher than those obtained with silver sols.

  16. Quantum corral resonance widths: lossy scattering as acoustics.

    PubMed

    Barr, Matthew C; Zaletel, Michael P; Heller, Eric J

    2010-09-08

    We present an approach to predicting extrinsic electron resonance widths within quantum corral nanostructures based on analogies with acoustics. Established quantum mechanical methods for calculating resonance widths, such as multiple scattering theory, build up the scattering atom by atom, ignoring the structure formed by the atoms, such as walls or enclosures. Conversely, particle-in-a-box models, assuming continuous walls, have long been successful in predicting quantum corral energy levels, but not resonance widths. In acoustics, partial reflection from walls and various enclosures has long been incorporated for determining reverberation times. Pursuing an exact analogy between the local density of states of a quantum corral and the acoustic impedance of a concert hall, we show electron lifetimes in nanoscopic structures of arbitrary convex shape are well accounted for by the Sabine formula for acoustic reverberation times. This provides a particularly compact and intuitive prescription for extrinsic finite lifetimes in a particle-in-a-box with leaky walls, including quantum corral atomic walls, given single particle scattering properties.

  17. Resonances of quantum mechanical scattering systems and Lax-Phillips scattering theory

    NASA Astrophysics Data System (ADS)

    Baumgärtel, Hellmut

    2010-11-01

    For selected classes of quantum mechanical scattering systems a canonical association of a decay semigroup is presented. The spectrum of the generator of this semigroup is a pure eigenvalue spectrum and it coincides with the set of all resonances. The essential condition for the results is the meromorphic continuability of the scattering matrix onto {C}setminus (-infty,0] and the rims {R}-± i0. Further finite multiplicity is assumed. The approach is based on an adaption of the Lax-Phillips scattering theory to semibounded Hamiltonians. It is applied to trace class perturbations with analyticity conditions. A further example is the potential scattering for central-symmetric potentials with compact support and angular momentum 0.

  18. Acoustic resonance scattering from a submerged anisotropic sphere

    NASA Astrophysics Data System (ADS)

    Hasheminejad, S. M.; Maleki, M.

    2008-03-01

    The resonance scattering theory (RST) is applied to the problem of sound scattering from an elastic transversely isotropic solid sphere suspended in an ideal acoustic fluid medium. The normal mode expansion technique in conjunction with the Frobenius power series solution method is utilized to deal with the material anisotropy. The presented model, which degenerates to the simple isotropic solution in the case of very weak anisotropy, is initially employed to study sensitivity of various resonant modes of vibration to perturbations in elements of the stiffness matrix. Employing a rigid background subtraction, the target’s spectrum of resonances is extracted from the relevant modal backscattering form functions and subsequently traced and discussed through Regge pole trajectory plots. Also, the backscattering form function and resonance spectra, along with the dispersion curves for selected transversely isotropic solid spheres with distinct degrees of material anisotropy, are calculated and discussed. The various modes of propagation associated with the Rayleigh, Whispering Gallery, and fluid-borne Scholte-Stoneley surface waves are identified and examined.

  19. Spectral Phonon Scattering from Sub-10 nm Surface Roughness Wavelengths in Metal-Assisted Chemically Etched Si Nanowires

    SciTech Connect

    Ghossoub, MG; Valavala, KV; Seong, M; Azeredo, B; Hsu, K; Sadhu, JS; Singh, PK; Sinha, S

    2013-03-06

    Frequency dependence in phonon surface scattering is a debated topic in fundamental phonon physics. Recent experiments and theory suggest such a phenomenon, but an independent agreement between the two remains elusive. We report low-temperature dependence of thermal conductivity in silicon nanowires fabricated using a two-step, metal-assisted chemical etch. By reducing etch rates down to 0.5 nm/s from the typical >100 nm/s, we report controllable roughening of nanowire surfaces and selectively focus on moderate roughness scales rather than the extreme scales investigated previously. This critically enables direct comparison with perturbation-based spectral scattering theory. Using experimentally characterized surface roughness, we show that a multiple scattering theory provides excellent agreement and explanation of the observed low-temperature dependence of rough surface nanowires. The theory does not employ any fitting parameters. A 5-10 nm roughness correlation length is typical in metal-assisted chemical etching and resonantly scatters dominant phonons in silicon, leading to the observed similar to T1.6-2.4 behavior. Our work provides fundamental and quantitative insight into spectral phonon scattering from rough surfaces. This advances applications of nanowires in thermoelectric energy conversion.

  20. Implications of resonant inelastic x-ray scattering data for theoretical models of cuprates

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Sushkov, Oleg P.

    2013-11-01

    There are two commonly discussed points of view in theoretical description of cuprate superconductors: (i) Cuprates can be described by the modified t-J model; (ii) overdoped cuprates are close to the regime of normal Fermi liquid (NFL). We argue that recent resonant inelastic x-ray scattering data challenge both points. While the modified t-J model describes well the strongly underdoped regime, it fails to describe high energy magnetic excitations when approaching optimal doping. This probably indicates failure of the Zhang-Rice singlet picture. In the overdoped regime the momentum-integrated spin structure factor S(ω) has the same intensity and energy distribution as that in an undoped parent compound. This implies that the entire spin spectral sum rule is saturated at ω≈2J, while in an NFL the spectral weight should saturate only at the total bandwidth which is much larger than 2J.

  1. Selective resonance enhancement of Raman scattering intensity in photoinduced nonradiative charge transfer

    NASA Astrophysics Data System (ADS)

    Bairamov, B. Kh.

    2016-04-01

    This paper reports on the formation of complexes consisting of isolated free-standing crystalline semiconductor quantum dots, for example, nc-Si/SiO2, functionalized by short oligonucleotides, for example, the single-stranded system d(20G, 20T). Here, d are deoxyribonucleotides, G and T are guanine and thymine nucleotides, respectively. It has been found that these complexes are unique objects for the elucidation of the specific features in the manifestation of new quantum-size effects in biomacromolecules. It has been demonstrated that the possibility exists of detecting and recording, in such complexes of biomacromolecules, spectrally selective resonance enhancement of Raman scattering intensity in fluctuations of nucleotide molecules due to coherent nonradiative transfer of a photoexcited electron and a hole at the interface of the complex. This dynamic optical imaging of spectral responses can be of applied interest for the development of nanobiophotonic technologies.

  2. Resonance Raman Scattering Studies of Gallium - - Aluminum-Arsenide Superlattices.

    NASA Astrophysics Data System (ADS)

    Gant, Thomas Andrew

    We have made resonance Raman scattering studies of folded LA phonons and quantized LO phonons in several GaAs-AlAs superlattices. The motivation for this work was to study the electronic structure and the electron -phonon interaction in these structures. The samples were not intentionally doped. The Raman spectra of optic phonons were usually taken at a temperature of 10 K or less. The folded acoustic phonon work was taken at temperatures ranging from 200-300 K in order to enhance the scattering by the thermal factor. Two samples in particular have received very close attention: sample 2292 (50 A GaAs- 20 A AlAs) and sample 3250 (20 A GaAs- 50 A AlAs). In sample 2292 we have made resonance studies of the folded LA phonons and the GaAs -like confined LO_2 mode near the second heavy hole exciton. The results on the folded acoustic phonons show a very strong resonance enhancement for the second order folded phonons, but very little for the first order. An interference between two different scattering channels (the n = 1 light hole and the n = 2 heavy hole subbands) seems to be responsible for this effect. The resonance profile for the LO_2 confined optic phonon in sample 2292 shows 4 peaks in the region from 1.8 eV to 2.05 eV. We have studied the dependence of this resonance profile on the power density. A higher power density was achieved by using the same laser power with a tighter focus. At the higher power density the peak at 1.93 eV (formerly the strongest peak present) vanished. This "bleaching" effect is related to screening due to the higher carrier density. In sample 3250 we have studied the polarization dependence of the resonance profiles of four peaks (LO _2, LO_4, LO_6, and an interface mode) near the lowest direct gap. The A_1 symmetry confined LO modes are seen in both polarized and depolarized geometries, in violation of the usual selection rule (polarized). A mechanism is proposed to explain this result, which has been previously observed by other

  3. Chemical Binding Effects in Neutron Resonance Scattering and Absorption.

    NASA Astrophysics Data System (ADS)

    Shamaoun, Adib Iskandar

    The Doppler broadening of neutron absorption and scattering resonances is an effect of considerable importance in calculating reactor parameters. This broadening is known to depend upon the state of the atom from which the scattering of the neutron occurs. This dependence is called the chemical binding effect. A key assumption in the usual computations of Doppler broadening is to ignore the dependence of the total resonance width on the chemical binding state of the compound nucleus. This is an excellent approximation for the gamma line. We derive an expression for the neutron line width as a function of the energy of the compound nucleus for an ideal gas. The influence of energy on the width with energy is examined at two different temperatures 4K and 1000K. It is found that these effects are very small, of the order of 10^{4-} . The assumption of constancy of the resonance width is thus shown to be a good approximation for the neutron line width. Also we examine the influence of the crystalline binding on the 6.67 eV resonance energy of U-238 line shape in uranium carbide and uranium dioxide. This model treats the crystal as a gas with an effective temperature and an effective mass determined by harmonic crystal phonon spectrum developed by Koppel and Houston. Based on this model, the line shape of U-238 is Gaussian plus a recoilless part. We also compute the broadening using a harmonic crystal model. As the temperature of U-238 target is decreased, disagreement between the two models becomes pronounced. However the results agree in the limiting case of high temperature. As the nucleus becomes more tightly bound, shifts in the resonance peak to lower energies are also observed. A general formula for the differential scattering cross section is developed starting from the transition probability (T-matrix). The formalism is applied to the gas and harmonic crystal models to determine the chemical binding effect. Although the resonance broadening is determined in

  4. Parallel Spectral Acquisition with an Ion Cyclotron Resonance Cell Array.

    PubMed

    Park, Sung-Gun; Anderson, Gordon A; Navare, Arti T; Bruce, James E

    2016-01-19

    Mass measurement accuracy is a critical analytical figure-of-merit in most areas of mass spectrometry application. However, the time required for acquisition of high-resolution, high mass accuracy data limits many applications and is an aspect under continual pressure for development. Current efforts target implementation of higher electrostatic and magnetic fields because ion oscillatory frequencies increase linearly with field strength. As such, the time required for spectral acquisition of a given resolving power and mass accuracy decreases linearly with increasing fields. Mass spectrometer developments to include multiple high-resolution detectors that can be operated in parallel could further decrease the acquisition time by a factor of n, the number of detectors. Efforts described here resulted in development of an instrument with a set of Fourier transform ion cyclotron resonance (ICR) cells as detectors that constitute the first MS array capable of parallel high-resolution spectral acquisition. ICR cell array systems consisting of three or five cells were constructed with printed circuit boards and installed within a single superconducting magnet and vacuum system. Independent ion populations were injected and trapped within each cell in the array. Upon filling the array, all ions in all cells were simultaneously excited and ICR signals from each cell were independently amplified and recorded in parallel. Presented here are the initial results of successful parallel spectral acquisition, parallel mass spectrometry (MS) and MS/MS measurements, and parallel high-resolution acquisition with the MS array system.

  5. Resonant L{sub II,III} x-ray Raman scattering from HCl

    SciTech Connect

    Saathe, C.; Rubensson, J.-E.; Nordgren, J.; Guimaraes, F. F.; Agui, A.; Guo, J.; Ekstroem, U.; Norman, P.; Gel'mukhanov, F.; Aagren, H.

    2006-12-15

    We have studied the spectral features of Cl L{sub II,III} resonant x-ray Raman scattering of HCl molecules in gas phase both experimentally and theoretically. The theory, formulated in the intermediate-coupling scheme, takes into account the spin-orbital and molecular-field splittings in the Cl 2p shells, as well as the Coulomb interaction of the core hole with unoccupied molecular orbitals. Experiment and theory display nondispersive dissociative peaks formed by decay transitions in both molecular and dissociative regions. The molecular and atomic peaks collapse in a single narrow resonance because the dissociative potentials of core-excited and final states are parallel to each other along the whole pathway of the nuclear wave packet.

  6. Resonant quasiparticle-ion scattering in anisotropic superfluid 3He

    NASA Astrophysics Data System (ADS)

    Salmelin, R. H.; Salomaa, M. M.

    1990-03-01

    Low-energy excitations in quantum fluids are most directly encountered by ions. In the superfluid phases of 3He the relevant elementary excitations are Bogoliubov quasiparticles, which undergo repeated scattering off an ion in the presence of a divergent density of states. We present a quantum-mechanical calculation of the resonant 3He quasiparticle-scattering-limited mobility for negative ions in the anisotropic bulk 3A (A phase) and 3P (polar phase) that is exact when the quasiparticles scatter elastically. We develop a numerical scheme to solve the singular equations for quasiparticle-ion scattering in the A and P phases. Both of these superfluid phases feature a uniaxially symmetric order parameter but distinct topology for the magnitude of the energy gap on the Fermi sphere, i.e., points versus lines of nodes. In particular, the perpetual orbital circulation of Cooper pairs in 3A results in a novel, purely quantum-mechanical intrinsic Magnus effect, which is absent in the polar phase, where Cooper pairs possess no spontaneous orbital angular momentum. This is of interest also for transport properties of heavy-fermion superconductors. We discuss the 3He quasiparticle-ion cross sections, which allow one to account for the mobility data with essentially no free parameters. The calculated mobility thus facilitates an introduction of ``ion spectroscopy'' to extract useful information on fundamental properties of the superfluid state, such as the temperature dependence of the energy gap in 3A.

  7. Cyclotron resonant scattering and absorption. [in gamma ray bursts

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Daugherty, Joseph K.

    1991-01-01

    The relativistic cross-sections for first-order absorption and second-order scattering are compared to determine the conditions under which the absorption cross-section is a good approximation to the much more complex scattering cross-section for purposes of modeling cyclotron lines in gamma-ray bursts. Differences in both the cross-sections and the line profiles are presented for a range of field strengths, angles, and electron temperatures. The relative difference of the cross-sections at one line width from resonance was found to increase with field strength and harmonic number. The difference is also strongly dependent on the photon angle to the magnetic field. For the field strength, 1.7 x 10 to the 12th G, and the angle inferred from the Ginga burst features, absorption is an excellent approximation for the profiles at the first and second harmonics.

  8. Diffractometer for soft x-ray resonant magnetic scattering

    NASA Astrophysics Data System (ADS)

    Grabis, J.; Nefedov, A.; Zabel, H.

    2003-09-01

    We report on the design and construction of a new diffractometer for soft x-ray resonant magnetic scattering which has been built at the Ruhr-University Bochum. The ultrahigh vacuum-compatible diffractometer comprises a two-circle goniometer and works in horizontal scattering geometry. Rotation of the detector and sample is realized by two differentially pumped rotating platforms with motors and gears external to the vacuum. The sample environment consists of a closed-cycle He cryostat that allows heating up to 600 K and applying a magnetic field of ±2.5 kOe. All functions of the experimental setup have been extensively tested at the BESSY II Synchrotron (beamline PM3). The experimental results demonstrate the performance of the instrument.

  9. 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.

  10. Spectral Kinetic Simulation of the Ideal Multipole Resonance Probe

    NASA Astrophysics Data System (ADS)

    Gong, Junbo; Wilczek, Sebastian; Szeremley, Daniel; Oberrath, Jens; Eremin, Denis; Dobrygin, Wladislaw; Schilling, Christian; Friedrichs, Michael; Brinkmann, Ralf Peter

    2015-09-01

    The term Active Plasma Resonance Spectroscopy (APRS) denotes a class of diagnostic techniques which utilize the natural ability of plasmas to resonate on or near the electron plasma frequency ωpe: An RF signal in the GHz range is coupled into the plasma via an electric probe; the spectral response of the plasma is recorded, and a mathematical model is used to determine plasma parameters such as the electron density ne or the electron temperature Te. One particular realization of the method is the Multipole Resonance Probe (MRP). The ideal MRP is a geometrically simplified version of that probe; it consists of two dielectrically shielded, hemispherical electrodes to which the RF signal is applied. A particle-based numerical algorithm is described which enables a kinetic simulation of the interaction of the probe with the plasma. Similar to the well-known particle-in-cell (PIC), it contains of two modules, a particle pusher and a field solver. The Poisson solver determines, with the help of a truncated expansion into spherical harmonics, the new electric field at each particle position directly without invoking a numerical grid. The effort of the scheme scales linearly with the ensemble size N.

  11. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  12. Superconducting pairing in resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Shi, Yifei; Benjamin, David; Demler, Eugene; Klich, Israel

    2016-09-01

    We develop a method to study the effect of the superconducting transition on the resonant inelastic x-ray scattering (RIXS) signal in superconductors with an order parameter with an arbitrary symmetry within a quasiparticle approach. As an example, we compare the direct RIXS signal below and above the superconducting transition for p -wave-type order parameters. For a p -wave order parameter with a nodal line, we show that, counterintuitively, the effect of the gap is most noticeable for momentum transfers in the nodal direction. This phenomenon may be naturally explained as a type of nesting effect.

  13. Resonant Inelastic Scattering Spectra of Free Molecules with Vibrational Resolution

    SciTech Connect

    Hennies, Franz; Pietzsch, Annette; Berglund, Martin; Foehlisch, Alexander; Schmitt, Thorsten; Strocov, Vladimir; Karlsson, Hans O.; Andersson, Joakim; Rubensson, Jan-Erik

    2010-05-14

    Inelastic x-ray scattering spectra excited at the 1s{sup -1{pi}}* resonance of gas phase O{sub 2} have been recorded with an overall energy resolution that allows for well-resolved vibrational progressions. The nuclear wave packet dynamics in the intermediate state is reflected in vibrational excitations of the electronic ground state, and by fine-tuning the excitation energy the dissociation dynamics in the predissociative B{sup '} {sup 3{Pi}}{sub g} final state is controlled.

  14. Resonances in Λd scattering and the Σ hypertriton

    NASA Astrophysics Data System (ADS)

    Afnan, I. R.; Gibson, B. F.

    1993-03-01

    Using separable NN and ΛN-ΣN potentials in the Faddeev equations, we have demonstrated that the predicted enhancement in the Λd cross section near the Σd threshold is associated with resonance poles in the scattering amplitude. The positions of these poles, on the second Riemann sheet of the complex energy plane, are determined by examining the eigenvalues of the kernel of the Faddeev equations. This suggests that for a certain class of ΛN-ΣN potentials we can form a Σ hypertriton with a width of about 8 MeV.

  15. Resonant impulsive-stimulated Raman scattering on malachite green

    SciTech Connect

    Chesnoy, J.; Mokhtari, A.

    1988-10-01

    We have studied in the femtosecond regime the transient dynamics of dichroism (anisotropic absorption), birefringence, and frequency shift induced by an intense femtosecond pump beam in the dye malachite green in solution. Vibrational quantum beats were observed superimposed on the saturated absorption and dispersion signals and quantitatively explained in terms of impulsive-stimulated Raman scattering close to an electronic resonance. The selectivity for observation of the vibrations in the two electronic states is described for the different experimental schemes. We discuss the access to vibrational and electronic dynamics in both ground and excited electronic states and compare the possibilities to those of previous techniques.

  16. Nuclear resonance scattering measurement of human iron stores

    SciTech Connect

    Wielopolski, L.; Ancona, R.C.; Mossey, R.T.; Vaswani, A.N.; Cohn, S.H.

    1985-07-01

    Hepatic iron stores were measured noninvasively in 31 patients (thalassemia, hemodialysis, hemosiderosis, refractory anemia) with suspected iron overload, employing a nuclear resonance scattering (NRS) technique. The thalassemia patients were undergoing desferrioxamine chelation therapy during the NRS measurements. The hemodialysis patients were measured before chelation therapy. Iron levels measured by NRS were in general agreement with those determined in liver biopsies by atomic absorption spectroscopy. In addition, NRS measurements from the thorax of some of these patients suggest that this method may also prove useful for clinical assessment of cardiac iron.

  17. Dependence of the spectral diffuse-direct irradiance ratio on aerosol spectral distribution and single scattering albedo

    NASA Astrophysics Data System (ADS)

    Kaskaoutis, D. G.; Kambezidis, H. D.; Dumka, U. C.; Psiloglou, B. E.

    2016-09-01

    This study investigates the modification of the clear-sky spectral diffuse-direct irradiance ratio (DDR) as a function of solar zenith angle (SZA), spectral aerosol optical depth (AOD) and single scattering albedo (SSA). The solar spectrum under various atmospheric conditions is derived with Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS) radiative transfer code, using the urban and continental aerosol models as inputs. The spectral DDR can be simulated with great accuracy by an exponentially decreasing curve, while the aerosol optical properties strongly affect the scattering processes in the atmosphere, thus modifying the DDR especially in the ultraviolet (UV) spectrum. Furthermore, the correlation between spectral DDR and spectral AOD can be represented precisely by an exponential function and can give valuable information about the dominance of specific aerosol types. The influence of aerosols on spectral DDR increases with increasing SZA, while the simulations using the urban aerosol model as input in SMARTS are closer to the measurements taken in the Athens urban environment. The SMARTS simulations are interrelated with spectral measurements and can be used for indirect estimations of SSA. Overall, the current work provides some theoretical approximations and functions that help in understanding the dependence of DDR on astronomical and atmospheric parameters.

  18. Resonant electronic Raman scattering: A BCS-like system

    NASA Astrophysics Data System (ADS)

    Rodrigues, Leonarde N.; Arantes, A.; Schüller, C.; Bell, M. J. V.; Anjos, V.

    2016-05-01

    In this paper we investigate the resonant intersubband Raman scattering of two-dimensional electron systems in GaAs-AlGaAs single quantum wells. Self-consistent calculations of the polarized and depolarized Raman cross sections show that the appearance of excitations at the unrenormalized single-particle energy are related to three factors: the extreme resonance regime, the existence of degeneracy in intersubband excitations of the electron gas, and, finally, degeneracy in the interactions between pairs of excitations. It is demonstrated that the physics that governs the problem is similar to the one that gives rise to the formation of the superconducting state in the BCS theory of normal metals. Comparison between experiment and theory shows an excellent agreement.

  19. Study of the resonant scattering in the Perseus cluster core with ASTRO-H SXS

    NASA Astrophysics Data System (ADS)

    Konami, Saori; Sato, Kosuke; Ohashi, Takaya; Churazov, Eugene; Zhuravleva, Irina; Sunyaev, Rashid

    Resonance lines from cores of galaxy clusters have significant optical depth, as predicted by Gilfanov, Sunyaev & Churazov (1987). We can constrain turbulence velocity from the level of suppression of the resonance lines, providing a good measure of dynamical condition of gas. The Soft X-ray Spectrometer (SXS) onboard ASTRO-H is a high-resolution spectrometer and capable of separating resonance lines from other line components. It is important to estimate the flux contamination due to the point spread function (PSF) of the X-ray telescope ~1.5’. Zhuravleva et al. (2013) constructed spectral models for the Perseus cluster which took into account modifications of line fluxes and shapes due to the resonant scattering effect as well as by radial variations of density, temperature and abundances of heavy elements. Line broadening by small-scale motions were also included. We performed simulation of these models by taking into account the pixel layout of SXS and PSF effect. The suppression of resonance line from H-like Fe will enable us to constrain gas velocities below 300 km/sec.

  20. Guided-mode-resonance coupled localized surface plasmons for dually resonance enhanced Raman scattering sensing

    NASA Astrophysics Data System (ADS)

    Wang, Zheng; Liu, Chao; Li, Erwen; Chakravarty, Swapnajit; Xu, Xiaochuan; Wang, Alan X.; Fan, D. L.; Chen, Ray T.

    2017-02-01

    Raman scattering spectroscopy is a unique tool to probe vibrational, rotational, and other low-frequency modes of a molecular system and therefore could be utilized to identify chemistry and quantity of molecules. However, the ultralow efficient Raman scattering, which is only 1/109 1/1014 of the excitation light due to the small Raman scattering cross-sections of molecules, have significantly hindered its development in practical sensing applications. The discovery of surface-enhanced Raman scattering (SERS) in the 1970s and the significant progress in nanofabrication technique, provide a promising solution to overcome the inherent issues of Raman spectroscopy. It is found that In the vicinity of nanoparticles and their junctions, the Raman signals of molecules can be significantly improved by an enhancement factor as high as 1010, due to the ultrahigh electric field generated by the localized surface plasmons resonance (LSPR), where the intensity of Raman scattering is proportional to the |E|4. In this work, we propose and demonstrate a new approach combining LSPR from nanocapsules with densely assembled silver nanoparticles (NC-AgNPs) and guidemode- resonance (GMR) from dielectric photonic crystal slabs (PCSs) for SERS substrates with robustly high performance.

  1. Tunable resonator-based devices for producing variable delays and narrow spectral linewidths

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor); Matsko, Andrey B. (Inventor); Ilchenko, Vladimir (Inventor)

    2006-01-01

    Devices with two or more coupled resonators to produce narrow spectral responses due to interference of signals that transmit through the resonators and techniques for operating such devices to achieve certain operating characteristics are described. The devices may be optical devices where optical resonators such as whispering gallery mode resonators may be used. In one implementation, at least one of the coupled optical resonators is a tunable resonator and is tuned to change its resonance frequency to tune the spectral response of the device. The described devices and techniques may be applied in optical filters, optical delays, optical waveform generators, and other applications.

  2. Scattering-Type Surface-Plasmon-Resonance Biosensors

    NASA Technical Reports Server (NTRS)

    Wang, Yu; Pain, Bedabrata; Cunningham, Thomas; Seshadri, Suresh

    2005-01-01

    Biosensors of a proposed type would exploit scattering of light by surface plasmon resonance (SPR). Related prior biosensors exploit absorption of light by SPR. Relative to the prior SPR biosensors, the proposed SPR biosensors would offer greater sensitivity in some cases, enough sensitivity to detect bioparticles having dimensions as small as nanometers. A surface plasmon wave can be described as a light-induced collective oscillation in electron density at the interface between a metal and a dielectric. At SPR, most incident photons are either absorbed or scattered at the metal/dielectric interface and, consequently, reflected light is greatly attenuated. The resonance wavelength and angle of incidence depend upon the permittivities of the metal and dielectric. An SPR sensor of the type most widely used heretofore includes a gold film coated with a ligand a substance that binds analyte molecules. The gold film is thin enough to support evanescent-wave coupling through its thickness. The change in the effective index of refraction at the surface, and thus the change in the SPR response, increases with the number of bound analyte molecules. The device is illuminated at a fixed wavelength, and the intensity of light reflected from the gold surface opposite the ligand-coated surface is measured as a function of the angle of incidence. From these measurements, the angle of minimum reflection intensity is determined

  3. Planar Multipol-Resonance-Probe: A Spectral Kinetic Approach

    NASA Astrophysics Data System (ADS)

    Friedrichs, Michael; Gong, Junbo; Brinkmann, Ralf Peter; Oberrath, Jens; Wilczek, Sebastian

    2016-09-01

    Measuring plasma parameters, e.g. electron density and electron temperature, is an important procedure to verify the stability and behavior of a plasma process. For this purpose the multipole resonance probe (MRP) represents a satisfying solution to measure the electron density. However the influence of the probe on the plasma through its physical presence makes it unattractive for some processes in industrial application. A solution to combine the benefits of the spherical MRP with the ability to integrate the probe into the plasma reactor is introduced by the planar model of the MRP (pMRP). Introducing the spectral kinetic formalism leads to a reduced simulation-circle compared to particle-in-cell simulations. The model of the pMRP is implemented and first simulation results are presented.

  4. High-spectral-resolution coherent anti-Stokes Raman scattering with interferometrically detected broadband chirped pulses.

    PubMed

    Jones, Gareth W; Marks, Daniel L; Vinegoni, Claudio; Boppart, Stephen A

    2006-05-15

    To achieve high-spectral-resolution multiplex coherent anti-Stokes Raman scattering (CARS), one typically uses a narrowband pump pulse and a broadband Stokes pulse. This is to ensure a correspondence between anti-Stokes and vibrational frequencies. We obtain high-resolution CARS spectra of isopropanol, using a broadband chirped pump pulse and a broadband Stokes pulse, by detecting the anti-Stokes pulse with spectral interferometry. With the temporally resolved anti-Stokes signal, we can remove the chirp of the anti-Stokes pulse and restore high spectral resolution while also rejecting nonresonant scattering.

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

    PubMed

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

    2014-11-01

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

  6. Impact of Compton scatter on material decomposition using a photon counting spectral detector

    NASA Astrophysics Data System (ADS)

    Lewis, Cale; Park, Chan-Soo; Fredette, Nathaniel R.; Das, Mini

    2017-03-01

    Photon counting spectral detectors are being investigated to allow better discrimination of multiple materials by collecting spectral data for every detector pixel. The process of material decomposition or discrimination starts with an accurate estimation of energy dependent attenuation of the composite object. Photoelectric effect and Compton scattering are two important constituents of the attenuation. Compton scattering while results in a loss of primary photon, also results in an increase in photon counts in the lower ene1rgy bins via multiple orders of scatter. This contribution to each energy bin may change with material properties, thickness and x-ray energies. There has been little investigation into the effect of this increase in counts at lower energies due to presence of these Compton scattered photons using photon counting detectors. Our investigations show that it is important to account for this effect in spectral decomposition problems.

  7. Scattering and Extinction Torques: How Plasmon Resonances Affect the Orientation Behavior of a Nanorod in Linearly Polarized Light.

    PubMed

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-01-21

    Linearly polarized light can exert an orienting torque on plasmonic nanorods. The torque direction has generally been considered to change when the light wavelength passes through a plasmon longitudinal resonance. Here, we use the Maxwell stress tensor to evaluate this torque in general terms. According to distinct light-matter interaction processes, the total torque is decomposed into scattering and extinction torques. The scattering torque tends to orient plasmonic nanorods parallel to the light polarization, independent of the choice of light wavelength. The direction of the extinction torque is not only closely tied to the excitation of plasmon resonance but also depends on the specific plasmon mode around which the light wavelength is tuned. Our findings show that the conventional wisdom that simply associates the total torque with the plasmon longitudinal resonances needs to be replaced with an understanding based on the different torque components and the details of spectral distribution.

  8. Study of the structure of 14O using resonant scattering

    NASA Astrophysics Data System (ADS)

    Ahn, Tan; TwinSol Collaboration

    2016-09-01

    Theoretical cluster models and recent experimental work have given evidence for prominent cluster structures in the light Z ≠ N nucleus 14C. In 14C, the presence of additional nucleons are important for the formation of unique cluster structures. In order to extend the search for cluster structures to proton-rich nuclei, we have performed an experiment using 10C + α resonant scattering to probe levels in 14O, the isobaric mirror of 14C. A radioactive beam of 10C produced with the TwinSol superconducting solenoids was impinged on a He gas target provided by the the Prototype Active-Target Time Projection-Chamber. Charged-particle tracks were recorded to deduce scattering cross sections. Results of the experiment and analysis in terms of R-matrix will be presented as well as possible future reactions that can complement our understanding of this scattering reaction. This work was supported by US NSF Grant No. PHY 14-19765.

  9. Noise power spectral density of a fibre scattered-light interferometer with a semiconductor laser source

    SciTech Connect

    Alekseev, A E; Potapov, V T

    2013-10-31

    Spectral characteristics of the noise intensity fluctuations at the output of a scattered-light interferometer, caused by phase fluctuations of semiconductor laser radiation are considered. This kind of noise is one of the main factors limiting sensitivity of interferometric sensors. For the first time, to our knowledge, the expression is obtained for the average noise power spectral density at the interferometer output versus the degree of a light source coherence and length of the scattering segment. Also, the approximate expressions are considered which determine the power spectral density in the low-frequency range (up to 200 kHz) and in the limiting case of extended scattering segments. The expression obtained for the noise power spectral density agrees with experimental normalised power spectra with a high accuracy. (interferometry of radiation)

  10. Resonance energy transfer: Spectral overlap, efficiency, and direction

    NASA Astrophysics Data System (ADS)

    Andrews, David L.; Rodríguez, Justo

    2007-08-01

    The efficiency and directedness of resonance energy transfer, by means of which electronic excitation passes between molecular units or subunits, fundamentally depend on the spectral features of donor and acceptor components. In particular, the flow of energy between chromophores in complex energy harvesting materials is crucially dependent on a spectral overlap integral reflecting the relative positioning and shapes of the absorption and fluorescence bands. In this paper, analytical results for this integral are derived for bands of Gaussian and log normal line shape; the methods also prove applicable to double Gaussian curves under suitable conditions. Underlying principles have been ascertained through further development of theory, with physically reasonable assumptions. Consideration of the Gaussian case, widely applicable to spectra of symmetric form, reveals that the directional efficiency of energy transfer depends equally on a frequency shift characterizing the spectroscopic gradient and the Stokes shift. On application to tryptophan residues, calculations based on a minimal parameter set give excellent agreement with experiment. Finally, an illustrative application highlights the critical role that the spectroscopic gradient and Stokes shift can exercise in extended, multichromophore energy harvesting systems.

  11. Collapse of the spin resonance spectral weight in overdoped Ba1-x K x Fe 2 As 2

    NASA Astrophysics Data System (ADS)

    Osborn, Ray; Rosenkranz, Stephan; Castellan, John-Paul; Goremychkin, Eugene; Chung, Duck-Young; Claus, Helmut; Kanatzidis, Mercouri; Guidi, Tatiana

    2011-03-01

    We report inelastic neutron scattering measurements of magnetic excitations in Ba 1-x Kx Fe 2 As 2 over a broad range of electron band filling within the superconducting phase. In an itinerant model, these excitations are resonantly enhanced when the superconducting energy gap changes sign on different parts of the electron Fermi surface. They are therefore sensitive both to the superconducting gap symmetry and to the Fermi surface geometry. Our results show that, in addition to becoming incommensurate because of the growing mismatch in the hole and electron Fermi surface volumes, the resonant spectral weight decreases proportionally to the resonance binding energy, vanishing at x ~ 0.72 . A tight-binding model including s+/- -symmetry pairing is able to reproduce these observations confirming that the resonance arises from the pairing of band electrons. Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.

  12. Supernova Resonance-scattering Line Profiles in the Absence of a Photosphere

    NASA Astrophysics Data System (ADS)

    Friesen, Brian; Baron, E.; Branch, David; Chen, Bin; Parrent, Jerod T.; Thomas, R. C.

    2012-11-01

    In supernova (SN) spectroscopy relatively little attention has been given to the properties of optically thick spectral lines in epochs following the photosphere's recession. Most treatments and analyses of post-photospheric optical spectra of SNe assume that forbidden-line emission comprises most if not all spectral features. However, evidence exists that suggests that some spectra exhibit line profiles formed via optically thick resonance-scattering even months or years after the SN explosion. To explore this possibility, we present a geometrical approach to SN spectrum formation based on the "Elementary Supernova" model, wherein we investigate the characteristics of resonance-scattering in optically thick lines while replacing the photosphere with a transparent central core emitting non-blackbody continuum radiation, akin to the optical continuum provided by decaying {}^{56}{\\protect {Co}} formed during the explosion. We develop the mathematical framework necessary for solving the radiative transfer equation under these conditions and calculate spectra for both isolated and blended lines. Our comparisons with analogous results from the Elementary Supernova code SYNOW reveal several marked differences in line formation. Most notably, resonance lines in these conditions form P Cygni-like profiles, but the emission peaks and absorption troughs shift redward and blueward, respectively, from the line's rest wavelength by a significant amount, despite the spherically symmetric distribution of the line optical depth in the ejecta. These properties and others that we find in this work could lead to misidentification of lines or misattribution of properties of line-forming material at post-photospheric times in SN optical spectra.

  13. SUPERNOVA RESONANCE-SCATTERING LINE PROFILES IN THE ABSENCE OF A PHOTOSPHERE

    SciTech Connect

    Friesen, Brian; Baron, E.; Branch, David; Chen Bin; Parrent, Jerod T.; Thomas, R. C.

    2012-11-15

    In supernova (SN) spectroscopy relatively little attention has been given to the properties of optically thick spectral lines in epochs following the photosphere's recession. Most treatments and analyses of post-photospheric optical spectra of SNe assume that forbidden-line emission comprises most if not all spectral features. However, evidence exists that suggests that some spectra exhibit line profiles formed via optically thick resonance-scattering even months or years after the SN explosion. To explore this possibility, we present a geometrical approach to SN spectrum formation based on the 'Elementary Supernova' model, wherein we investigate the characteristics of resonance-scattering in optically thick lines while replacing the photosphere with a transparent central core emitting non-blackbody continuum radiation, akin to the optical continuum provided by decaying {sup 56}Co formed during the explosion. We develop the mathematical framework necessary for solving the radiative transfer equation under these conditions and calculate spectra for both isolated and blended lines. Our comparisons with analogous results from the Elementary Supernova code SYNOW reveal several marked differences in line formation. Most notably, resonance lines in these conditions form P Cygni-like profiles, but the emission peaks and absorption troughs shift redward and blueward, respectively, from the line's rest wavelength by a significant amount, despite the spherically symmetric distribution of the line optical depth in the ejecta. These properties and others that we find in this work could lead to misidentification of lines or misattribution of properties of line-forming material at post-photospheric times in SN optical spectra.

  14. Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering.

    PubMed

    Troyan, Ivan; Gavriliuk, Alexander; Rüffer, Rudolf; Chumakov, Alexander; Mironovich, Anna; Lyubutin, Igor; Perekalin, Dmitry; Drozdov, Alexander P; Eremets, Mikhail I

    2016-03-18

    High-temperature superconductivity remains a focus of experimental and theoretical research. Hydrogen sulfide (H2S) has been reported to be superconducting at high pressures and with a high transition temperature. We report on the direct observation of the expulsion of the magnetic field in H2S compressed to 153 gigapascals. A thin (119)Sn film placed inside the H2S sample was used as a sensor of the magnetic field. The magnetic field on the (119)Sn sensor was monitored by nuclear resonance scattering of synchrotron radiation. Our results demonstrate that an external static magnetic field of about 0.7 tesla is expelled from the volume of (119)Sn foil as a result of the shielding by the H2S sample at temperatures between 4.7 K and approximately 140 K, revealing a superconducting state of H2S.

  15. Homogenization of electromagnetic crystals formed by uniaxial resonant scatterers

    NASA Astrophysics Data System (ADS)

    Belov, Pavel A.; Simovski, Constantin R.

    2005-08-01

    Dispersion properties of electromagnetic crystals formed by small uniaxial resonant scatterers (magnetic or electric) are studied using the local field approach. The goal of the study is to determine the conditions under which the homogenization of such crystals is possible. Therefore the consideration is limited to the frequency region where the wavelength in the host medium is larger than the lattice periods. It is demonstrated that, together with the known restriction for the homogenization related to the large values of the material parameters, there is an additional restriction related to their small absolute values. On the other hand, the homogenization becomes allowed in both cases of large and small material parameters for special directions of propagation. Two unusual effects inherent to the crystals under consideration are revealed: a flat isofrequency contour that allows subwavelength imaging using the canalization regime and birefringence of the extraordinary modes which can be used for beam splitting.

  16. A spectral emission mask for digital tropospheric scatter transmission

    NASA Astrophysics Data System (ADS)

    Galpin, R. K. P.

    1983-03-01

    A spectral emission mask definition for high power digital radio transmission is proposed. Developed for use in the specification of digitalized ACE high troposcatter links, it is offered for consideration by industry and frequency planning authorities. Similar in form to the FCC mask definition for digital LOS radio, the proposed definition is believed to be a reasonable compromise between minimizing interference into adjacent radio channel allocations and avoiding the imposition of costly constraints upon the manufacturers and operators. Computer simulations supported by spectral measurements at 10 kW have shown that well designed filtering (with negligible intersymbol interference) before the high power amplifier is very effective in reducing out of band emission, and that the proposed mask can be satisfied with a signal having a bandwidth utilization efficiency of 1.6 bit/s/Hz when operating at 2 dB below saturation of the klystron amplifier.

  17. Resonant Raman scattering in self-assembled quantum dots

    SciTech Connect

    Menendez-Proupin, E.; Trallero-Giner, C.; Ulloa, S. E.

    1999-12-15

    A theoretical treatment for first-order resonant Raman scattering in self-assembled quantum dots (SAQD's) of different materials is presented. The dots are modeled as cylindrical disks with elliptical cross section, to simulate shape and confinement anisotropies obtained from the SAQD growth conditions. Coulomb interaction between electron and hole is considered in an envelope function Hamiltonian approach and the eigenvalues and eigenfunctions are obtained by a matrix diagonalization technique. By including excitonic intermediate states in the Raman process, the scattering efficiency and cross section are calculated for long-range Froehlich exciton-phonon interaction. The Froehlich interaction in the SAQD is considered in an approach in which both the mechanical and electrostatic matching boundary conditions are fulfilled at the SAQD interfaces. Exciton and confined phonon selection rules are derived for Raman processes. Characteristic results for SAQD's are presented, including InAs dots in GaAs, as well as CdSe dots in ZnSe substrates. We analyze how Raman spectroscopy would give information on carrier masses, confinement anisotropy effects, and SAQD geometry. (c) 1999 The American Physical Society.

  18. Resonance Rayleigh scattering measurement of aminoglycoside antibiotics with Evans Blue.

    PubMed

    Liu, Shao-Pu; Hu, Xiao-Li; Luo, Hong-Qun

    2003-06-01

    In a weak acid medium, some aminoglycoside antibiotics, such as kanamycin (KANA), gentamicin (GEN), tobramycin (TOB) and neomycin (NEO), or acid bisazo dye Evans Blue (EB) can only produce very weak resonance Rayleigh scattering (RRS) signals. However, when two agents react with each other to form ion-association complexes, the RRS intensity can be greatly enhanced and a new RRS spectrum with a significant enhancement of the RRS intensity in the wavelength range from 350 nm to 600 nm can be observed. The maximum scattering peak is at 570 nm. There is a linear relationship between the RRS intensity and the antibiotic concentration in the range of 0.01-6.0 microg mL(-1) at 570 nm. This RRS method for the determination of aminoglycoside antibiotics at trace-amount levels has been developed. The detection limits (3sigma) of the four antibiotics, whose order of sensitivity from high to low ranks as KANA > NEO > TOB > GEN, are 5.2-6.9 ng mL(-1). This method has good selectivity and has been successfully applied to the quick determination of antibiotics not only for injections and ear drops, but for clinic serum samples as well. In addition, the reaction mechanism by using a quantum chemistry method and the influencing factors of the RRS spectra and the enhancement reasons of RRS have been discussed.

  19. Carbon nanohorn-based nanofluids: characterization of the spectral scattering albedo

    NASA Astrophysics Data System (ADS)

    Mercatelli, Luca; Sani, Elisa; Giannini, Annalisa; di Ninni, Paola; Martelli, Fabrizio; Zaccanti, Giovanni

    2012-02-01

    The full characterization of the optical properties of nanofluids consisting of single-wall carbon nanohorns of different morphologies in aqueous suspensions is carried out using a novel spectrophotometric technique. Information on the nanofluid scattering and absorption spectral characteristics is obtained by analyzing the data within the single scattering theory and validating the method by comparison with previous monochromatic measurements performed with a different technique. The high absorption coefficient measured joint to the very low scattering albedo opens promising application perspectives for single-wall carbon nanohorn-based fluid or solid suspensions. The proposed approximate approach can be extended also to other low-scattering turbid media. PACS: 78.35.+c Brillouin and Rayleigh scattering, other light scattering; 78.40.Ri absorption and reflection spectra, fullerenes and related materials; 81.05.U- carbon/carbon-based materials; 78.67.Bf optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, nanocrystals, nanoparticles, and nanoclusters.

  20. Carbon nanohorn-based nanofluids: characterization of the spectral scattering albedo.

    PubMed

    Mercatelli, Luca; Sani, Elisa; Giannini, Annalisa; Di Ninni, Paola; Martelli, Fabrizio; Zaccanti, Giovanni

    2012-02-01

    The full characterization of the optical properties of nanofluids consisting of single-wall carbon nanohorns of different morphologies in aqueous suspensions is carried out using a novel spectrophotometric technique. Information on the nanofluid scattering and absorption spectral characteristics is obtained by analyzing the data within the single scattering theory and validating the method by comparison with previous monochromatic measurements performed with a different technique. The high absorption coefficient measured joint to the very low scattering albedo opens promising application perspectives for single-wall carbon nanohorn-based fluid or solid suspensions. The proposed approximate approach can be extended also to other low-scattering turbid media.PACS: 78.35.+c Brillouin and Rayleigh scattering, other light scattering; 78.40.Ri absorption and reflection spectra, fullerenes and related materials; 81.05.U- carbon/carbon-based materials; 78.67.Bf optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, nanocrystals, nanoparticles, and nanoclusters.

  1. One-dimensional plasmonic hotspots located between silver nanowire dimers evaluated by surface-enhanced resonance Raman scattering

    NASA Astrophysics Data System (ADS)

    Itoh, Tamitake; Yamamoto, Yuko S.; Kitahama, Yasutaka; Balachandran, Jeyadevan

    2017-03-01

    Hotspots of surface-enhanced resonance Raman scattering (SERRS) are localized within 1 nm at gaps or crevices of plasmonic nanoparticle dimers. We demonstrate SERRS hotspots with volumes that are extended in one dimension tens of thousand times compared to standard zero-dimensional hotspots using crevices of plasmonic nanowire dimers. According to the polarization measurements, a plasmon resonance in the direction along the dimer width generates SERRS hotspots. SERRS images show oscillating patterns between edges of the hotspot. The SERRS intensity becomes the strongest at the edges, indicating that Fabry-Perot-type resonance of surface plasmons is involved in the Raman enhancement. These optical properties of the SERRS hotspots are quantitatively reproduced by numerical calculations based on the electromagnetic (EM) mechanism. EM coupling energy between dye molecule excitons and plasmons is evaluated using spectral changes in plasmon resonance reflected in a loss of SERRS activity at the hotspots. The coupling energies are consistent with the calculated EM enhancement factors.

  2. 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.

  3. Resonant Raman Scattering Studies of Iii-V Semiconductor Microstructures

    NASA Astrophysics Data System (ADS)

    Delaney, Malcolm Emil

    1991-02-01

    Raman spectroscopy, an inelastic light scattering technique, explores III-V semiconductors by conveying crystal lattice structural information and by probing carrier dynamics both directly and via the electron-phonon interaction. We have examined three physical systems accentuating three aspects of Raman utility. Al_{rm x}Ga_{rm 1-x} As alloy work emphasizes electronic behavior, migration enhanced epitaxy (MEE) studies highlight structural results, and a phonon-assisted lasing project underscores electron -phonon interaction. The disorder-induced frequency difference between the dipole-forbidden and dipole-allowed longitudinal optic (LO) modes in Al_{rm x} Ga_{rm 1-x}As alloys has been investigated as a function of laser photon energy, aluminum mole fraction x, and the indirect versus direct nature of the electronic band gap. For the indirect gap alloy, the intermediate resonant state is an X-valley electron effectively localized because of its short inelastic lifetime. Raman scattering via this state is described by a calculation of the Raman susceptibility that considers the random alloy potential generated by local concentration fluctuations. MEE is a new growth technology that can order these materials in two spatial directions. In a GaSb/AlSb system we show Raman evidence of this ordering via observation of zone folded acoustic modes and compare to AlAs/GaAs results. In other work resonant Raman documents the effects on the dipole-forbidden interface mode of a periodic corrugation introduced in AlAs barrier GaAs single quantum wells. Finally, we investigate "phonon-assisted" lasing in photopumped quantum well heterostructure lasers. Resonant Raman is the natural choice to probe this system purported to have an enhanced electron-phonon interaction. For both the AlGaAs/GaAs and AlGaAs/GaAs/InGaAs structures examined, we provide evidence that indicates first order "phonon -assisted" lasing is actually renormalized band gap luminescence filtered by absorption from

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

    PubMed

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

    2015-03-01

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

  5. Controllable emission of a dipolar source coupled with a magneto-dielectric resonant subwavelength scatterer

    PubMed Central

    Rolly, Brice; Geffrin, Jean-Michel; Abdeddaim, Redha; Stout, Brian; Bonod, Nicolas

    2013-01-01

    We demonstrate experimentally and theoretically that a local excitation of a single scatterer of relative dielectric permittivity ε = 6 permits to excite broad dipolar and quadrupolar electric and magnetic resonances that shape the emission pattern in an unprecedented way. By suitably positioning the feed with respect to the sphere at a λ/3 distance, this compact antenna is able to spectrally sort the electromagnetic emission either in the forward or in the backward direction, together with a high gain in directivity. Materials with ε = 6 can be found in the whole spectrum of frequencies promising Mie antennas to become an enabling technology in numbers of applications, ranging from quantum single photon sources to telecommunications. PMID:24165924

  6. Resonant Inelastic X-ray Scattering Study of the Electronic Structure of Cu2O

    SciTech Connect

    Hill, J.P.; Kim, Y.-J.; Yamaguchi, H.; Gog, T.; Casa, D.

    2010-05-15

    A resonant inelastic x-ray scattering study of the electronic structure of the semiconductor cuprous oxide, Cu{sub 2}O, is reported. When the incident x-ray energy is tuned to the CuK-absorption edge, large enhancements of the spectral features corresponding to the electronic transitions between the valence band and the conduction band are observed. A feature at 6.5 eV can be well described by an interband transition from occupied states of mostly Cu3d character to unoccupied states with mixed 3d, 4s, and O2p character. In addition, an insulating band gap is observed, and the momentum dependence of the lower bound is measured along the {Gamma}-R direction. This is found to be in good agreement with the valence-band dispersion measured with angle-resolved photoemission spectroscopy.

  7. A deformable nanoplasmonic membrane reveals universal correlations between plasmon resonance and surface enhanced Raman scattering.

    PubMed

    Kang, Minhee; Kim, Jae-Jun; Oh, Young-Jae; Park, Sang-Gil; Jeong, Ki-Hun

    2014-07-09

    A quantitative correlation between plasmon resonance and surface enhanced Raman scattering (SERS) signals is revealed by using a novel active plasmonic method, that is, a deformable nanoplasmonic membrane. A single SERS peak has the maximum gain at the corresponding plasmon resonance wavelength, which has the maximum extinction product of an excitation and the corresponding Raman scattering wavelengths.

  8. Branching ratio study of resonant X-ray scattering intensities of GdB4

    NASA Astrophysics Data System (ADS)

    Cho, Byeong-Gwan; Hwang, Sangyun; Koo, Tae-Young; Ji, Sungdae; Cho, Beongki; Lee, Ki Bong

    2017-08-01

    Resonant X-ray scattering measurements for a GdB4 single crystal have been carried out at Gd L 3- and L 2-edges. Branching ratios between x-ray scattering intensities at two x-ray energies are different for resonance peaks. Their analysis shows different anisotropic characters of 5 d electron states of Gd ions corresponding to the peaks.

  9. Resonant states for the scattering of slow particles by screened potentials

    SciTech Connect

    Bruk, Yu. M. Voloshchuk, A. N.

    2016-09-15

    Partial resonant situations for the scattering of slow particles with nonzero angular momenta by short-range screened Yukawa and Buckingham potentials are considered. The problem of electron scattering by a hydrogen atom placed in a plasma medium is discussed. A general scheme of resonances has been constructed in the Pais approximation.

  10. Resonances in rotationally inelastic scattering of OH(X2Π) with helium and neon.

    PubMed

    Gubbels, Koos B; Ma, Qianli; Alexander, Millard H; Dagdigian, Paul J; Tanis, Dick; Groenenboom, Gerrit C; van der Avoird, Ad; van de Meerakker, Sebastiaan Y T

    2012-04-14

    We present detailed calculations on resonances in rotationally and spin-orbit inelastic scattering of OH (X(2)Π, j = 3/2, F(1), f) radicals with He and Ne atoms. We calculate new ab initio potential energy surfaces for OH-He, and the cross sections derived from these surfaces compare well with the recent crossed beam scattering experiment of Kirste et al. [Phys. Rev. A 82, 042717 (2010)]. We identify both shape and Feshbach resonances in the integral and differential state-to-state scattering cross sections, and we discuss the prospects for experimentally observing scattering resonances using Stark decelerated beams of OH radicals.

  11. Charge-magnetic interference resonant scattering studies of ferromagnetic crystals and thin films

    SciTech Connect

    Haskel, D.; Kravtsov, E.; Choi, Y.; Lang, J.C.; Islam, Z.; Srajer, G.; Jiang, J.S.; Bader, S.D.; Canfield, Paul C.

    2012-06-15

    The element- and site-specificity of X-ray resonant magnetic scattering (XRMS) makes it an ideal tool for furthering our understanding of complex magnetic systems. In the hard X-rays, XRMS is readily applied to most antiferromagnets where the relatively weak resonant magnetic scattering (10 −2–10 −6Ic) is separated in reciprocal space from the stronger, Bragg charge scattered intensity, Ic. In ferro(ferri)magnetic materials, however, such separation does not occur and measurements of resonant magnetic scattering in the presence of strong charge scattering are quite challenging. We discuss the use of charge-magnetic interference resonant scattering for studies of ferromagnetic (FM) crystals and layered films. We review the challenges and opportunities afforded by this approach, particularly when using circularly polarized X-rays.We illustrate current capabilities at the Advanced Photon Source with studies aimed at probing site-specific magnetism in ferromagnetic crystals, and interfacial magnetism in films.

  12. 3D LTE spectral line formation with scattering in red giant stars

    NASA Astrophysics Data System (ADS)

    Hayek, W.; Asplund, M.; Collet, R.; Nordlund, Å.

    2011-05-01

    Aims: We investigate the effects of coherent isotropic continuum scattering on the formation of spectral lines in local thermodynamic equilibrium (LTE) using 3D hydrodynamical and 1D hydrostatic model atmospheres of red giant stars. Methods: Detailed radiative transfer with coherent and isotropic continuum scattering is computed for 3D hydrodynamical and 1D hydrostatic models of late-type stellar atmospheres using the SCATE code. Opacities are computed in LTE, while a coherent and isotropic scattering term is added to the continuum source function. We investigate the effects of scattering by comparing continuum flux levels, spectral line profiles and curves of growth for different species with calculations that treat scattering as absorption. Results: Rayleigh scattering is the dominant source of scattering opacity in the continuum of red giant stars. Photons may escape from deeper, hotter layers through scattering, resulting in significantly higher continuum flux levels beneath a wavelength of λ ≲ 5000 Å. The magnitude of the effect is determined by the importance of scattering opacity with respect to absorption opacity; we observe the largest changes in continuum flux at the shortest wavelengths and lowest metallicities; intergranular lanes of 3D models are more strongly affected than granules. Continuum scattering acts to increase the profile depth of LTE lines: continua gain more brightness than line cores due to their larger thermalization depth in hotter layers. We thus observe the strongest changes in line depth for high-excitation species and ionized species, which contribute significantly to photon thermalization through their absorption opacity near the continuum optical surface. Scattering desaturates the line profiles, leading to larger abundance corrections for stronger lines, which reach -0.5 dex at 3000 Å for Fe ii lines in 3D with excitation potential χ = 2 eV at [Fe/H] = -3.0. The corrections are less severe for low-excitation lines, longer

  13. Experimental studies on output, spatial, and spectral characteristics of a microdroplet dye laser containing intralipid as a highly scattering medium

    SciTech Connect

    Taniguchi, Hiroshi; Tanosaki, Shinji; Tsujita, Kazuhiro; Inaba, Humio

    1996-11-01

    Lasing characteristics of Rhodamine 6G dye-doped microdroplets containing highly scattering fat emulsion Intralipid-10% are studied experimentally. Noteworthy findings are that well-defined lasing threshold can be observed and one order or more magnitude enhancement of emission intensity with suitable (optimum) conditions of the Intralipid mixing ratio, in comparison with original neat-dye lasing microdroplets. The authors present and discuss the measured results of input-output intensities for different dye concentrations and dye-Intralipid mixing ratios in this high-gain laser dye-soft scatterer system and microscope images of spatial distribution of light emission from both the microdroplets containing neat-dye and dye-Intralipid mixture. It was found that almost no-lasing neat-dye microdroplets, which have either much higher or much lower dye concentration, can achieve lasing by substituting suitably certain amounts of the Intralipid, causing multiple light scattering. Spectral measurements of lasing outputs from the Rhodamine 6G dye-Intralipid microdroplets show the tendency of the disappearance of the well-known mode structures, owing to the morphology-dependent resonances of this microspherical cavity inherent to the neat-dye microdroplets. It is their belief that the present results make this novel method of dye-Intralipid microsystem very attractive for a variety of future applications, including diagnostic tools for highly sensitive detection and identification of small quantity objects and species embedded or hidden in highly scattering media.

  14. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  16. Solution of electromagnetic scattering and radiation problems using a spectral domain approach - A review

    NASA Technical Reports Server (NTRS)

    Mittra, R.; Ko, W. L.; Rahmat-Samii, Y.

    1979-01-01

    This paper presents a brief review of some recent developments on the use of the spectral-domain approach for deriving high-frequency solutions to electromagnetics scattering and radiation problems. The spectral approach is not only useful for interpreting the well-known Keller formulas based on the geometrical theory of diffraction (GTD), it can also be employed for verifying the accuracy of GTD and other asymptotic solutions and systematically improving the results when such improvements are needed. The problem of plane wave diffraction by a finite screen or a strip is presented as an example of the application of the spectral-domain approach.

  17. Adaptation of the University of Wisconsin High Spectral Resolution Lidar for Polarization and Multiple Scattering Measurements

    NASA Technical Reports Server (NTRS)

    Eloranta, E. W.; Piironen, P. K.

    1996-01-01

    Quantitative lidar measurements of aerosol scattering are hampered by the need for calibrations and the problem of correcting observed backscatter profiles for the effects of attenuation. The University of Wisconsin High Spectral Resolution Lidar (HSRL) addresses these problems by separating molecular scattering contributions from the aerosol scattering; the molecular scattering is then used as a calibration target that is available at each point in the observed profiles. While the HSRl approach has intrinsic advantages over competing techniques, realization of these advantages requires implementation of a technically demanding system which is potentially very sensitive to changes in temperature and mechanical alignments. This paper describes a new implementation of the HSRL in an instrumented van which allows measurements during field experiments. The HSRL was modified to measure depolarization. In addition, both the signal amplitude and depolarization variations with receiver field of view are simultaneously measured. This allows for discrimination of ice clouds from water clouds and observation of multiple scattering contributions to the lidar return.

  18. The double-resonance enhancement of stimulated low-frequency Raman scattering in silver-capped nanodiamonds

    NASA Astrophysics Data System (ADS)

    Baranov, A. N.; Butsen, A. V.; Ionin, A. A.; Ivanova, A. K.; Kuchmizhak, A. A.; Kudryashov, S. I.; Kudryavtseva, A. D.; Levchenko, A. O.; Rudenko, A. A.; Saraeva, I. N.; Strokov, M. A.; Tcherniega, N. V.; Zayarny, D. A.

    2017-09-01

    Hybrid plasmonic-dielectric nano- and (sub)microparticles exhibit magnetic and electrical dipolar Mie-resonances, which makes them useful as efficient basic elements in surface-enhanced spectroscopy, non-linear light conversion and nanoscale light control. We report the stimulated low-frequency Raman scattering (SLFRS) of a nanosecond ruby laser radiation (central wavelength λ = 694.3 nm (full-width at half-maximum ≈ 0.015 cm-1), gaussian 1/e-intensity pulsewidth τ ≈ 20 ns, TEM00-mode pulse energy Emax ≈ 0.3 J) in nanodiamond (R ≈ 120 nm) hydrosols, induced via optomechanical coherent excitation of fundamental breathing eigen-modes, and the two-fold enhancement of SLFRS in Ag-decorated nanodiamonds, characterized by hybrid dipolar resonances of electrical (silver) and magnetic (diamond) nature. Hybrid metal-dielectric particles were prepared by means of nanosecond IR-laser ablation of solid silver target in diamond hydrosols with consecutive Ag-capping of diamonds, and were characterized by scanning electron microscopy, UV-vis, photoluminescence and energy-dispersive X-ray spectroscopy. Intensities of the SLFR-scattered components and their size-dependent spectral shifts were measured in the highly sensitive stimulated scattering regime, indicating the high (≈ 30%) SLFRS conversion efficiency and the resonant character of the scattering species.

  19. Dark-field spectral imaging microscope for localized surface plasmon resonance-based biosensing

    NASA Astrophysics Data System (ADS)

    Yim, Sang-Youp; Park, Jin-Ho; Kim, Min-Gon

    2015-07-01

    Localized surface plasmon resonance (LSPR) of metal nanoparticles makes red-shift of extinction wavelength with an increase in the refractive index at the surface of the metal nanoparticles. Since biomolecules bound to the metal nanoparticle's surface induce refractive index change, biosensing based on LSPR effect can be possible by monitoring scattering or absorption spectrum changes. Generally, however, conventional method detects ensemble averaged LSPR signal of a huge number of metal nanoparticles. Here, we have constructed a dark-field spectral imaging microscope in order to monitor the scattering spectra of individual metal nanoparticles, simultaneously. Gold nanorod (GNR) and aptamer are employed to detect ochratoxin A (OTA) related to a carcinogenic illness. An aptamer-target binding mechanism promotes wavelength shift of extinction spectra due to refractive index change within sensing volume of GNR by structural change of aptamer. A number of GNRs can be identified in a dark-field LSPR image, simultaneously. A typical spectrum of a GNR exhibits red-shift after target binding of molecules and OTA detection is extended to the very low concentration of 1 pM level.

  20. Anomalous Spectral Shift of Near- and Far-Field Plasmonic Resonances in Nanogaps

    PubMed Central

    2016-01-01

    The near-field and far-field spectral response of plasmonic systems are often assumed to be identical, due to the lack of methods that can directly compare and correlate both responses under similar environmental conditions. We develop a widely tunable optical technique to probe the near-field resonances within individual plasmonic nanostructures that can be directly compared to the corresponding far-field response. In tightly coupled nanoparticle-on-mirror constructs with nanometer-sized gaps we find >40 meV blue-shifts of the near-field compared to the dark-field scattering peak, which agrees with full electromagnetic simulations. Using a transformation optics approach, we show such shifts arise from the different spectral interference between different gap modes in the near- and far-field. The control and tuning of near-field and far-field responses demonstrated here is of paramount importance in the design of optical nanostructures for field-enhanced spectroscopy, as well as to control near-field activity monitored through the far-field of nano-optical devices. PMID:27077075

  1. Anomalous Spectral Shift of Near- and Far-Field Plasmonic Resonances in Nanogaps.

    PubMed

    Lombardi, Anna; Demetriadou, Angela; Weller, Lee; Andrae, Patrick; Benz, Felix; Chikkaraddy, Rohit; Aizpurua, Javier; Baumberg, Jeremy J

    2016-03-16

    The near-field and far-field spectral response of plasmonic systems are often assumed to be identical, due to the lack of methods that can directly compare and correlate both responses under similar environmental conditions. We develop a widely tunable optical technique to probe the near-field resonances within individual plasmonic nanostructures that can be directly compared to the corresponding far-field response. In tightly coupled nanoparticle-on-mirror constructs with nanometer-sized gaps we find >40 meV blue-shifts of the near-field compared to the dark-field scattering peak, which agrees with full electromagnetic simulations. Using a transformation optics approach, we show such shifts arise from the different spectral interference between different gap modes in the near- and far-field. The control and tuning of near-field and far-field responses demonstrated here is of paramount importance in the design of optical nanostructures for field-enhanced spectroscopy, as well as to control near-field activity monitored through the far-field of nano-optical devices.

  2. Determination of thickness, refractive index, and spectral scattering of an inhomogeneous thin film with rough interfaces

    SciTech Connect

    Pradeep, J. Anto; Agarwal, Pratima

    2010-08-15

    The magnitude of spectral transmittance and reflectance is affected by the presence of inhomogeneity and interfacial roughness. Therefore, the methods, based on the magnitude of spectral transmittance and reflectance, are not adequate for the determination of thickness and optical constants of films with inhomogeneity and interfacial roughness. The present article proposes a method for the determination of thickness and refractive index using only the positions of the interference fringes in spectral transmittance and reflectance at two different angles of incidence. The proposed method is verified through numerical simulations, which result in <1% error for the film thickness. The complete parametrical dependence of spectral transmittance and reflectance of inhomogeneous film with rough interfaces on a substrate have been worked out for the film on transparent and opaque substrates, respectively. The spectrum envelopes have been solved simultaneously and the mathematical formulae are given for the determination of spectral scattering due to inhomogeneity and interfacial roughness for both transmittance and reflectance cases.

  3. Picosecond spectral coherent anti-Stokes Raman scattering imaging with principal component analysis of meibomian glands

    PubMed Central

    Lin, Chia-Yu; Suhalim, Jeffrey L.; Nien, Chyong Ly; Miljković, Miloš D.; Diem, Max; Jester, James V.; Potma, Eric. O.

    2011-01-01

    The lipid distribution in the mouse meibomian gland was examined with picosecond spectral anti-Stokes Raman scattering (CARS) imaging. Spectral CARS data sets were generated by imaging specific localized regions of the gland within tissue sections at consecutive Raman shifts in the CH2 stretching vibrational range. Spectral differences between the location specific CARS spectra obtained in the lipid-rich regions of the acinus and the central duct were observed, which were confirmed with a Raman microspectroscopic analysis, and attributed to meibum lipid modifications within the gland. A principal component analysis of the spectral data set reveals changes in the CARS spectrum when transitioning from the acini to the central duct. These results demonstrate the utility of picosecond spectral CARS imaging combined with multivariate analysis for assessing differences in the distribution and composition of lipids in tissues. PMID:21361667

  4. Reply to "Comment on `Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping'"

    NASA Astrophysics Data System (ADS)

    Rykovanov, S. G.; Geddes, C. G. R.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2016-09-01

    We reply to Terzic and Krafft's forgoing Comment [Phys. Rev. Accel. Beams, Comment on "Controlling the spectral shape of nonlinear Thomson scattering with proper laser chirping" 19 (2016)]. We disagree with the conclusion of the Comment regarding the novelty of solutions and the citations presented in our paper.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  6. Assessing multiple quality attributes of peaches using spectral absorption and scattering properties

    USDA-ARS?s Scientific Manuscript database

    The objective of this research was to measure the spectral absorption and reduced scattering coefficients of peaches, using a hyperspectral imaging-based spatially-resolved method, for maturity/quality assessment. A newly developed optical property measuring instrument was used for acquiring hypersp...

  7. Assessing the sensitivity and robustness of prediction models for apple firmness using spectral scattering technique

    USDA-ARS?s Scientific Manuscript database

    Spectral scattering is useful for nondestructive sensing of fruit firmness. Prediction models, however, are typically built using multivariate statistical methods such as partial least squares regression (PLSR), whose performance generally depends on the characteristics of the data. The aim of this ...

  8. Ultrasonic Thermometry Inside Tissues Based on High-resolution Detection of Spectral Shifts in Overtones of Scattering Signals

    NASA Astrophysics Data System (ADS)

    Bazán, I.; Ramos, A.; Ramírez, A.; Leija, L.

    Some research results of cooperation works in biomedical engineering, established among current national projects of Mexico and Spain, are resumed. They are related to coordinated activities of three R & D groups, with the aim to achieve high-resolution ultrasonic thermometry into tissue phantoms with internal reflectors of a non-invasive way. Advanced spectral techniques are being used to extract thermal information in echo-signals acquired from biological phantoms with internal structures having a quasi-regular scattering distribution as, for instance, it happens in the liver tissues where a rather regular separation between scatterers has been reported. These techniques can indicate pathologies related to thermal increases due to the presence of disease. Small changes with temperature can be detected in the location of overtones of the fundamental resonance related to the separation of internal reflectors. But, this requires discarding the influence of the echoes noise on the thermal estimation results. A first evaluation of these spectral analysis techniques is performed, using echo-signals acquired from a phantom in the temperature range with medical interest, where the noise influence is shown for different levels of SNR in the echoes, using signals derived of a mathematical model for hepatic tissue echoes, where the average power, signal to noise ratio and inter-arrival time standard deviation, were taken into account. It seems that our high-resolution spectral option could be applied to detect some pathologies in tissues having regular scattering, but new advances must be performed with real tissues, in order to confirm the potential resolution of this approach.

  9. Plasmon-resonant Raman spectroscopy in metallic nanoparticles: Surface-enhanced scattering by electronic excitations

    NASA Astrophysics Data System (ADS)

    Carles, R.; Bayle, M.; Benzo, P.; Benassayag, G.; Bonafos, C.; Cacciato, G.; Privitera, V.

    2015-11-01

    Since the discovery of surface-enhanced Raman scattering (SERS) 40 years ago, the origin of the "background" that is systematically observed in SERS spectra has remained questionable. To deeply analyze this phenomenon, plasmon-resonant Raman scattering was recorded under specific experimental conditions on a panel of composite multilayer samples containing noble metal (Ag and Au) nanoparticles. Stokes, anti-Stokes, and wide, including very low, frequency ranges have been explored. The effects of temperature, size (in the nm range), embedding medium (SiO2, Si3N4, or TiO2) or ligands have been successively analyzed. Both lattice (Lamb modes and bulk phonons) and electron (plasmon mode and electron-hole excitations) dynamics have been investigated. This work confirms that in Ag-based nanoplasmonics composite layers, only Raman scattering by single-particle electronic excitations accounts for the background. This latter appears as an intrinsic phenomenon independently of the presence of molecules on the metallic surface. Its spectral shape is well described by revisiting a model developed in the 1990s for analyzing electron scattering in dirty metals, and used later in superconductors. The gs factor, that determines the effective mean-free path of free carriers, is evaluated, gsexpt=0.33 ±0.04 , in good agreement with a recent evaluation based on time-dependent local density approximation gstheor=0.32 . Confinement and interface roughness effects at the nanometer range thus appear crucial to understand and control SERS enhancement and more generally plasmon-enhanced processes on metallic surfaces.

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

    PubMed

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

    2008-09-01

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

  11. Fano resonance-induced negative optical scattering force on plasmonic nanoparticles.

    PubMed

    Chen, Huajin; Liu, Shiyang; Zi, Jian; Lin, Zhifang

    2015-02-24

    We demonstrate theoretically that Fano resonance can induce a negative optical scattering force acting on plasmonic nanoparticles in the visible light spectrum when an appropriate manipulating laser beam is adopted. Under the illumination of a zeroth-order Bessel beam, the plasmonic nanoparticle at its Fano resonance exhibits a much stronger forward scattering than backward scattering and consequently leads to a net longitudinal backward optical scattering force, termed Fano resonance-induced negative optical scattering force. The extinction spectra obtained based on the Mie theory show that the Fano resonance arises from the interference of simultaneously excited multipoles, which can be either a broad electric dipole mode and a narrow electric quadrupole mode, or a quadrupole and an octupole mode mediated by the broad electric dipole. Such Fano resonance-induced negative optical scattering force is demonstrated to occur for core-shell, homogeneous, and hollow metallic particles and can therefore be expected to be universal for many other nanostructures exhibiting Fano resonance, adding considerably to the flexibility of optical micromanipulation on the plasmonic nanoparticles. More interestingly, the flexible tunability of the Fano resonance by particle morphology opens up the possibility of tailoring the optical scattering force accordingly, offering an additional degree of freedom to optical selection and sorting of plasmonic nanoparticles.

  12. Effect of the third π ∗ resonance on the angular distributions for electron-pyrimidine scattering

    NASA Astrophysics Data System (ADS)

    Mašín, Zdeněk; Gorfinkiel, Jimena D.

    2016-07-01

    We present a detailed analysis of the effect of the well known third π∗ resonance on the angular behaviour of the elastic cross section in electron scattering from pyrimidine. This resonance, occurring approximately at 4.7 eV, is of mixed shape and core-excited character. Experimental and theoretical results show the presence of a peak/dip behaviour in this energy range, that is absent for other resonances. Our investigations show that the cause of the peak/dip is an interference of background p-wave to p-wave scattering amplitudes with the amplitudes for resonant scattering. The equivalent resonance in pyrazine shows the same behaviour and the effect is therefore likely to appear in other benzene-like molecules. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  13. Resonant scattering of ultrarelativistic electrons in the strong field of a pulsed laser wave

    NASA Astrophysics Data System (ADS)

    Lebed', A. A.; Padusenko, E. A.; Roshchupkin, S. P.

    2016-02-01

    Electron-electron scattering in a strong field of a pulsed laser wave is studied theoretically. Resonant scattering kinematics at the small polar angles for electron ultrarelativistic energy is studied in detail. Compact analytical expressions for the amplitude and the differential cross section for wave elliptical polarization are obtained under resonant conditions. The resonant cross section of electron-electron scattering is shown to decrease sharply with increasing the electron ultrarelativistic energies for weak and moderately strong fields. It was demonstrated that the resonant cross section of electron-electron scattering at wave circular polarization is four times greater than the corresponding cross section at linear polarization. The resonant cross section may exceed the corresponding cross section of a field-free process: by 5-6 orders of magnitude for electron MeV-energy and petawatt optical lasers (PHELIX, Vulcan); and 8-9 orders for multipetawatt laser fields within the femtosecond range (Vulcan10, ELI).

  14. Resonant Mie scattering in infrared spectroscopy of biological materials--understanding the 'dispersion artefact'.

    PubMed

    Bassan, Paul; Byrne, Hugh J; Bonnier, Franck; Lee, Joe; Dumas, Paul; Gardner, Peter

    2009-08-01

    Infrared spectroscopic cytology is potentially a powerful clinical tool. However, in order for it to be successful, practitioners must be able to extract reliably a pure absorption spectrum from a measured spectrum that often contains many confounding factors. The most intractable problem to date is the, so called, dispersion artefact which most prominently manifests itself as a sharp decrease in absorbance on the high wavenumber side of the amide I band in the measured spectrum, exhibiting a derivative-like line shape. In this paper we use synchrotron radiation FTIR micro-spectroscopy to record spectra of mono-dispersed poly(methyl methacrylate) (PMMA) spheres of systematically varying size and demonstrate that the spectral distortions in the data can be understood in terms of resonant Mie scattering. A full understanding of this effect will enable us to develop strategies for deconvolving the scattering contribution and recovering the pure absorption spectrum, thus removing one of the last technological barriers to the development of clinical spectroscopic cytology.

  15. Effect of broken symmetry on resonant inelastic x-ray scattering from undoped cuprates

    NASA Astrophysics Data System (ADS)

    Igarashi, Jun-ichi; Nagao, Tatsuya

    2015-05-01

    We study the magnetic excitation spectra of resonant inelastic x-ray scattering (RIXS) at the L-edge from undoped cuprates beyond the fast collision approximation. We analyse the effect of the symmetry breaking ground state on the RIXS process of the Heisenberg model by using a projection procedure. We derive the expressions of the scattering amplitude in both one-magnon and two-magnon excitation channels. Each of them consists of the isotropic and anisotropic contributions. The latter is a new finding and attributed to the long range order of the ground state. The presence of anisotropic terms is supported by numerical calculations on a two-dimensional spin cluster. We express the RIXS spectra in the form of spin-correlation functions with the coefficients evaluated on the cluster, and calculate the function in a two dimensional system within the 1/S expansion. Due to the anisotropic terms, the spectral intensities are considerably enhanced around momentum transfer q = 0 in both one-magnon and two-magnon excitation channels. This finding may be experimentally confirmed by examining carefully the q-dependence of the spectra.

  16. Determination of bismuth in pharmaceutical products using phosphoric acid as molecular probe by resonance light scattering.

    PubMed

    Yun, Yanru; Cui, Fengling; Geng, Shaoguang; Jin, Jianhua

    2012-01-01

    A novel method for the sensitive determination of bismuth(III) in pharmaceutical products using phosphoric acid as a molecular probe by resonance light scattering (RLS) is discussed. In 0.5 mol/L phosphoric acid (H3 PO4) medium, bismuth(III) reacted with PO4 (3-) to form an ion association compound, which resulted in the significant enhancement of RLS intensity and the appearance of the corresponding RLS spectral characteristics. The maximum scattering peak of the system existed at 364 nm. Under optimal conditions, there was linear relationship between the relative intensity of RLS and concentration of bismuth(III) in the range of 0.06-10.0 µg/mL for the system. A low detection limit for bismuth(III) of 3.22 ng/mL was achieved. The relative standard deviations (RSD) for the determination of 0.40 and 0.80 µg/mL bismuth(III) were 2.1% and 1.1%, respectively, for five determinations. Based on this fact, a simple, rapid, and sensitive method was developed for the determination of bismuth(III) at nanogram level by RLS technique with a common spectrofluorimeter. This analytical system was successfully applied to determine the trace amounts of bismuth(III) in pharmaceutical products, which was in good agreement with the results obtained by atomic absorption spectrometry (AAS).

  17. Modeling of Outer Radiation Belt Electron Scattering due to Spatial and Spectral Properties of ULF Waves

    NASA Astrophysics Data System (ADS)

    Tornquist, Mattias

    The research presented in this thesis covers wave-particle interactions for relativistic (0.5-10 MeV) electrons in Earth's outer radiation belt (r = 3-7 RE, or L-shells: L = 3-7) interacting with magnetospheric Pc-5 (ULF) waves. This dissertation focuses on ideal models for short and long term electron energy and radial position scattering caused by interactions with ULF waves. We use test particle simulations to investigate these wave-particle interactions with ideal wave and magnetic dipole fields. We demonstrate that the wave-particle phase can cause various patterns in phase space trajectories, i.e. local acceleration, and that for a global electron population, for all initial conditions accounted for, has a negligible net energy scattering. Working with GSM polar coordinates, the relevant wave field components are EL, Ephi and Bz, where we find that the maximum energy scattering is 3-10 times more effective for Ephi compared to EL in a magnetic dipole field with a realistic dayside compression amplitude. We also evaluate electron interactions with two coexisting waves for a set of small frequency separations and phases, where it is confirmed that multi-resonant transport is possible for overlapping resonances in phase space when the Chirikov criterion is met (stochasticity parameter K = 1). The electron energy scattering enhances with decreasing frequency separation, i.e. increasing K, and is also dependent on the phases of the waves. The global acceleration is non-zero, can be onset in about 1 hour and last for > 4 hours. The adiabatic wave-particle interaction discussed up to this point can be regarded as short-term scattering ( tau ˜ hours ). When the physical problem extends to longer time scales (tau ˜ days ) the process ceases to be adiabatic due to the introduction of stochastic element in the system and becomes a diffusive process. We show that any mode in a broadband spectrum can contribute to the total diffusion rate for a particular drift

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

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Lock, James A.

    1992-01-01

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

  19. Vibrationally resonant imaging of a single living cell by supercontinuum-based multiplex coherent anti-Stokes Raman scattering microspectroscopy

    NASA Astrophysics Data System (ADS)

    Kano, Hideaki; Hamaguchi, Hiro-O.

    2005-02-01

    Supercontinuum-based multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy has been applied to vibrational imaging of a living fission yeast cell. We have successfully extracted only a vibrationally resonant CARS image from a characteristic spectral profile in the C-H stretching vibrational region. Using our simple but sensitive analysis, the vibrational contrast is significantly improved in comparison with a CARS imaging at a fixed Raman shift. The CARS image of a living yeast cell indicates several areas at which the signal is remarkably strong. They are considered to arise from mitochondria.

  20. Strong forward-backward asymmetry of stimulated Raman scattering in lithium-niobate-based whispering gallery resonators.

    PubMed

    Leidinger, M; Sturman, B; Buse, K; Breunig, I

    2016-06-15

    We show experimentally and prove theoretically that the pump-power thresholds of stimulated Raman scattering (SRS) in lithium-niobate-based whispering gallery resonators (WGRs) are strongly different for the signal waves propagating in the backward and forward directions with respect to the pump wave. This feature is due to a strong polaritonic effect. It leads to a cascade of alternating forward-backward Raman lines with increasing pump power. The measured polarization and spectral properties of SRS are in good agreement with theory. Similar properties have to be inherent in other WGRs made of polar crystals.

  1. A fast numerical solution of scattering by a cylinder: Spectral method for the boundary integral equations

    NASA Technical Reports Server (NTRS)

    Hu, Fang Q.

    1994-01-01

    It is known that the exact analytic solutions of wave scattering by a circular cylinder, when they exist, are not in a closed form but in infinite series which converges slowly for high frequency waves. In this paper, we present a fast number solution for the scattering problem in which the boundary integral equations, reformulated from the Helmholtz equation, are solved using a Fourier spectral method. It is shown that the special geometry considered here allows the implementation of the spectral method to be simple and very efficient. The present method differs from previous approaches in that the singularities of the integral kernels are removed and dealt with accurately. The proposed method preserves the spectral accuracy and is shown to have an exponential rate of convergence. Aspects of efficient implementation using FFT are discussed. Moreover, the boundary integral equations of combined single and double-layer representation are used in the present paper. This ensures the uniqueness of the numerical solution for the scattering problem at all frequencies. Although a strongly singular kernel is encountered for the Neumann boundary conditions, we show that the hypersingularity can be handled easily in the spectral method. Numerical examples that demonstrate the validity of the method are also presented.

  2. Structural and dynamical properties of chlorinated hydrocarbons studied with resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Bohinc, R.; Žitnik, M.; Bučar, K.; Kavčič, M.; Carniato, S.; Journel, L.; Guillemin, R.; Marchenko, T.; Kawerk, E.; Simon, M.; Cao, W.

    2016-04-01

    We present a theoretical and experimental study of resonant inelastic x-ray scattering on a large group of chlorinated hydrocarbons: CH3Cl, CH2Cl2, CHCl3, CCl4, CH3CH2Cl, ClCH2CH2Cl, CH3CHCl2, CH3CCl3, C2H2Cl2-iso, C2H2Cl2-cis, C2H2Cl2-trans, and C6H5Cl. Differences in structural and dynamical properties of the molecules generated by diverse chemical environments are observed in the measured Cl(Kα) spectral maps as well as in the Cl(K) total fluorescence yield spectra. The energy position, relative intensity, and the width of the Franck-Condon distribution of low-lying σ∗ and π∗ resonances are extracted by a fitting procedure taking into account the experimental broadening. The theoretical values obtained with the transition potential and Δ Kohn-Sham methods are in good agreement with the experimental parameters indicating subtle differences due to variations in the molecular structure.

  3. Structural and dynamical properties of chlorinated hydrocarbons studied with resonant inelastic x-ray scattering.

    PubMed

    Bohinc, R; Žitnik, M; Bučar, K; Kavčič, M; Carniato, S; Journel, L; Guillemin, R; Marchenko, T; Kawerk, E; Simon, M; Cao, W

    2016-04-07

    We present a theoretical and experimental study of resonant inelastic x-ray scattering on a large group of chlorinated hydrocarbons: CH3Cl, CH2Cl2, CHCl3, CCl4, CH3CH2Cl, ClCH2CH2Cl, CH3CHCl2, CH3CCl3, C2H2Cl2-iso, C2H2Cl2-cis, C2H2Cl2-trans, and C6H5Cl. Differences in structural and dynamical properties of the molecules generated by diverse chemical environments are observed in the measured Cl(K(α)) spectral maps as well as in the Cl(K) total fluorescence yield spectra. The energy position, relative intensity, and the width of the Franck-Condon distribution of low-lying σ* and π* resonances are extracted by a fitting procedure taking into account the experimental broadening. The theoretical values obtained with the transition potential and Δ Kohn-Sham methods are in good agreement with the experimental parameters indicating subtle differences due to variations in the molecular structure.

  4. Experimental implementation of coded aperture coherent scatter spectral imaging of cancerous and healthy breast tissue samples

    NASA Astrophysics Data System (ADS)

    Lakshmanan, Manu N.; Greenberg, Joel A.; Samei, Ehsan; Kapadia, Anuj J.

    2015-03-01

    A fast and accurate scatter imaging technique to differentiate cancerous and healthy breast tissue is introduced in this work. Such a technique would have wide-ranging clinical applications from intra-operative margin assessment to breast cancer screening. Coherent Scatter Computed Tomography (CSCT) has been shown to differentiate cancerous from healthy tissue, but the need to raster scan a pencil beam at a series of angles and slices in order to reconstruct 3D images makes it prohibitively time consuming. In this work we apply the coded aperture coherent scatter spectral imaging technique to reconstruct 3D images of breast tissue samples from experimental data taken without the rotation usually required in CSCT. We present our experimental implementation of coded aperture scatter imaging, the reconstructed images of the breast tissue samples and segmentations of the 3D images in order to identify the cancerous and healthy tissue inside of the samples. We find that coded aperture scatter imaging is able to reconstruct images of the samples and identify the distribution of cancerous and healthy tissues (i.e., fibroglandular, adipose, or a mix of the two) inside of them. Coded aperture scatter imaging has the potential to provide scatter images that automatically differentiate cancerous and healthy tissue inside of ex vivo samples within a time on the order of a minute.

  5. Single-scattering properties of ice crystals, snowflakes, and graupel particles in the microwave spectral region

    NASA Astrophysics Data System (ADS)

    Yang, P.; Tang, G.; Stegmann, P.; Ding, J.

    2016-12-01

    The single-scattering properties, namely the scattering phase matrix, extinction cross section, single-scattering albedo, and backscattering cross section, of ice crystals, snowflakes, and graupel particles in the microwave spectral region are important to remote sensing implementations based on observations by passive and active microwave sensors. The relevant electromagnetic scattering simulations are quite challenging because the corresponding size parameters are still large enough to prohibit the applicability of the Rayleigh scattering model. In this talk, we will present the single-scattering properties of ice crystals, snowflakes, and graupel particles at various microwave frequencies from 1 GHz to 874 GHz with particle maximum dimensions ranging from 2 µm to 10 mm. The dependence of the ice refractive index on temperature is considered at four different temperatures (160 K, 200 K, 230 K, and 270 K). State-of-the-art electromagnetic scattering solution methods (specifically, a synergistic combination of the invariant imbedding T-matrix method and the improved geometrical optics method) are employed for the present simulations. Twelve ice crystal habits (specifically, 10-plate aggregate, 5-plate aggregate, 8-column aggregate, solid hexagonal column, hollow hexagonal column, hexagonal plate, solid bullet rosette, hollow bullet rosette, droxtal, oblate spheroid, prolate spheroid, and sphere) are considered. In addition, we use a bi-continuous medium model to consider the morphology of particles with a porous structure such as rimed ice and graupel in electromagnetic scattering simulations. Single scattering simulation results are compared with those obtained using conventional homogeneous effective medium models for the particle porosity. Moreover, we illustrate the potential applications of the present microwave single-scattering property datasets towards active and passive remote sensing implementations.

  6. The spectral energy distribution of the scattered light from dark clouds

    NASA Technical Reports Server (NTRS)

    Mattila, Kalevi; Schnur, G. F. O.

    1989-01-01

    A dark cloud is exposed to the ambient radiation field of integrated starlight in the Galaxy. Scattering of starlight by the dust particles gives rise to a diffuse surface brightness of the dark nebula. The intensity and the spectrum of this diffuse radiation can be used to investigate, e.g., the scattering parameters of the dust, the optical thickness of the cloud, and as a probe of the ambient radiation field at the location of the cloud. An understanding of the scattering process is also a prerequisite for the isolation of broad spectral features due to fluorescence or to any other non-scattering origin of the diffuse light. Model calculations are presented for multiple scattering in a spherical cloud. These calculations show that the different spectral shapes of the observed diffuse light can be reproduced with standard dust parameters. The possibility to use the observed spectrum as a diagnostic tool for analyzing the thickness of the cloud and the dust particle is discussed.

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

    PubMed

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

    2015-02-05

    A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex=λem=330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N=3) of 0.05-0.12 μg mL(-1) was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Resonance scattering detection of trace microalbumin using immunonanogold probe as the catalyst of Fehling reagent-glucose reaction.

    PubMed

    Jiang, Zhiliang; Huang, Yujuan; Liang, Aihui; Pan, Hongchen; Liu, Qingye

    2009-02-15

    A novel and sensitive resonance scattering (RS) spectral immunoassay for the determination of microalbumin (Malb) was developed, based on the catalytic effect of immunonanogold (ING) probe on Fehling reagent-glucose reaction, and resonance scattering effect of Cu(2)O particles. Nanogold particles in size of 10nm were used to label goat anti-human microalbumin (GMalb) to obtain an ING probe (AuGMalb) for Malb. The probe produced unspecific aggregation in pH 5.0 citric acid-Na(2)HPO(4) buffer solutions. Upon addition of Malb, the dispersed ING complex formed. The ING complex in supernatant was obtained by centrifuging and was used as catalyst for the reaction between Fehling reagent and glucose to form the Cu(2)O particles to amplify the resonance scattering signal at 610 nm. With addition of Malb, the ING complex in the supernatant increased and the RS intensity at 610 nm (I(610 nm)) enhanced linearly. The enhanced intensity DeltaI(610 nm) was proportional to the Malb concentration in the range of 0.014-0.43 ng ml(-1), with a detection limit of 7.2 pg ml(-1). The proposed method was applied to detect Malb in human urine sample with satisfactory results.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  10. The Three-Wave Resonant Interaction Equations: Spectral and Numerical Methods

    NASA Astrophysics Data System (ADS)

    Degasperis, Antonio; Conforti, Matteo; Baronio, Fabio; Wabnitz, Stefan; Lombardo, Sara

    2011-06-01

    The spectral theory of the integrable partial differential equations which model the resonant interaction of three waves is considered with the purpose of numerically solving the direct spectral problem for both vanishing and non vanishing boundary values. Methods of computing both the continuum spectrum data and the discrete spectrum eigenvalues are given together with examples of such computations. The explicit spectral representation of the Manley-Rowe invariants is also displayed.

  11. Using Single-Scattering Albedo Spectral Curvature to Characterize East Asian Aerosol Mixtures

    NASA Technical Reports Server (NTRS)

    Li, Jing; Carlson, Barbara E.; Lacis, Andrew A.

    2015-01-01

    Spectral dependence of aerosol single-scattering albedo (SSA) has been used to infer aerosol composition. In particular, aerosol mixtures dominated by dust absorption will have monotonically increasing SSA with wavelength while that dominated by black carbon absorption has monotonically decreasing SSA spectra. However, by analyzing SSA measured at four wavelengths, 440, 675, 870, and 1020 nm from the Aerosol Robotic Network data set, we find that the SSA spectra over East Asia are frequently peaked at 675 nm. In these cases, we suggest that SSA spectral curvature, defined as the negative of the second derivative of SSA as a function of wavelength, can provide additional information on the composition of these aerosol mixtures. Aerosol SSA spectral curvatures for East Asia during fall and winter are considerably larger than those found in places primarily dominated by biomass burning or dust aerosols. SSA curvature is found to increase as the SSA magnitude decreases. The curvature increases with coarse mode fraction (CMF) to a CMF value of about 0.4, then slightly decreases or remains constant at larger CMF. Mie calculations further verify that the strongest SSA curvature occurs at approx. 40% dust fraction, with 10% scattering aerosol fraction. The nonmonotonic SSA spectral dependence is likely associated with enhanced absorption in the shortwave by dust, absorption by black carbon at longer wavelengths, and also the flattened absorption optical depth spectral dependence due to the increased particle size.

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

    PubMed

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

    2016-09-20

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

  13. Arbitrary phase modulation for optical spectral control and suppression of stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Harish, Achar V.; Nilsson, Johan

    2015-05-01

    We investigate the use of external phase modulation to broaden the linewidth of a laser source. We use nonlinear optimization to find phase modulations that create nearly tophat-shaped discrete spectra and thus the highest total power within a limited linewidth and a limited peak spectral power density. Such phase modulations and spectra can be realized with an arbitrary waveform generator (AWG) and are attractive for suppressing stimulated Brillouin scattering in optical fiber. Compared to alternative modulation approaches, the AWG benefits from a large number of degrees of freedom and well-controlled spectral phase in the AWG output.

  14. Photon scattering studies of the giant dipole resonance in medium weight nuclei

    SciTech Connect

    Bowles, T.J.; Holt, R.J.; Jackson, H.E.; Laszewski, R.M.; McKeown, R.D.; Nathan, A.M.; Specht, J.R.

    1981-11-01

    Quasimonochromatic photons have been used to measure elastic and inelastic photon scattering cross sections in the giant dipole resonance region of /sup 52/Cr, Fe, /sup 60/Ni, /sup 92/Mo, and /sup 96/Mo in an experiment in which the elastic and inelastic scattering are resolved. The elastic scattering cross sections show clear evidence for isospin splitting of the giant dipole resonance. The inelastic scattering to low-lying vibrational levels, which is a measure of the coupling between the giant dipole resonance and collective surface vibrations, is in qualitative agreement with the predictions of the dynamic collective model. However, when examined in detail, this model does not provide an adequate description of the scattering data.

  15. Estimates of the Spectral Aerosol Single Sea Scattering Albedo and Aerosol Radiative Effects during SAFARI 2000

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Pilewskie, Peter; Schmid, Beat; Russell, Philip B.

    2003-01-01

    Using measurements of the spectral solar radiative flux and optical depth for 2 days (24 August and 6 September 2000) during the SAFARI 2000 intensive field experiment and a detailed radiative transfer model, we estimate the spectral single scattering albedo of the aerosol layer. The single scattering albedo is similar on the 2 days even though the optical depth for the aerosol layer was quite different. The aerosol single scattering albedo was between 0.85 and 0.90 at 350 nm, decreasing to 0.6 in the near infrared. The magnitude and decrease with wavelength of the single scattering albedo are consistent with the absorption properties of small black carbon particles. We estimate the uncertainty in the single scattering albedo due to the uncertainty in the measured fractional absorption and optical depths. The uncertainty in the single scattering albedo is significantly less on the high-optical-depth day (6 September) than on the low-optical-depth day (24 August). On the high-optical-depth day, the uncertainty in the single scattering albedo is 0.02 in the midvisible whereas on the low-optical-depth day the uncertainty is 0.08 in the midvisible. On both days, the uncertainty becomes larger in the near infrared. We compute the radiative effect of the aerosol by comparing calculations with and without the aerosol. The effect at the top of the atmosphere (TOA) is to cool the atmosphere by 13 W/sq m on 24 August and 17 W/sq m on 6 September. The effect on the downward flux at the surface is a reduction of 57 W/sq m on 24 August and 200 W/sq m on 6 September. The aerosol effect on the downward flux at the surface is in good agreement with the results reported from the Indian Ocean Experiment (INDOEX).

  16. Fano resonance and improved sensing performance in a spectral-simplified optofluidic micro-bubble resonator by introducing selective modal losses.

    PubMed

    Liao, Jie; Wu, Xiang; Liu, Liying; Xu, Lei

    2016-04-18

    The spectral mode density in optical micro-bubble resonators is reduced by introducing a loss element of UV curable adhesive to selectively suppress the whispering gallery modal resonances. Asymmetric Fano resonant profile appears after spectral simplification, and the sharp slope amplifies the detecting intensity change by 4.3 times when sensing the liquid core refractive index change.

  17. 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.

  18. Spectral and Spatial Distribution of the Scattered Radiation of AN Electron Radiotherapy Beam

    NASA Astrophysics Data System (ADS)

    Bartesaghi, G.; Conti, V.; Mascagna, V.; Prest, M.; Mozzanica, A.; Frigerio, G.; Monti, A.; Vallazza, E.

    2006-04-01

    The characterization of the radiation scattered by the collimating system of a linear accelerator for medical applications is becoming a must given the increase in the survival of the radio-treated patients. This paper describes both the spectral and spatial study of the scattered radiation of an electron beam in the energy range 6-20 MeV, produced by a Varian CLINAC 1800 accelerator at the Radiotherapy Unit of the Sant'Anna Hospital in Como. The detectors used are plastic and fiber scintillators characterized by a timing response of ≈ 25 nsec in order to cope with the high fluxes. The results have been compared with a Montecarlo simulation based on Geant 3.21 and are presented both in terms of spectral and dose distributions.

  19. Evidence for Resonance Scattering in the X-ray Spectrum of Zeta Puppis

    NASA Technical Reports Server (NTRS)

    Leutenegger, Maurice

    2008-01-01

    We present XMM-Newton Reflection Grating Spectrometer observations of pairs of X-ray emission line profiles from the 0 star Zeta Pup that originate from the same He-like ion. The two profiles in each pair have different shapes and cannot both be consistently fit by models assuming the same wind parameters. We show that the differences in profile shape can be accounted for in a model including the effects of resonance scattering, which affects the resonance line in the pair but not the intercombination line. This implies that resonance scattering is also important in single resonance lines, where its effect is difficult to distinguish from a low effective continuum optical depth in the wind. Thus, resonance scattering may help reconcile X-ray line profile shapes with literature mass-loss rates.

  20. Fermi-Edge Singularity in the Vicinity of the Resonant Scattering Condition

    NASA Astrophysics Data System (ADS)

    Mkhitaryan, V. V.; Raikh, M. E.

    2011-05-01

    Fermi-edge absorption theory predicting the spectrum A(ω)∝ω-2δ0/π+δ02/π2 relies on the assumption that scattering phase δ0 is frequency independent. The dependence of δ0 on ω becomes crucial near the resonant condition, where the phase changes abruptly by π. In this limit, because of the finite time spent by electron on a resonant level, the scattering is dynamic. We incorporate the finite time delay into the theory, solve the Dyson equation with a modified kernel, and find that, near the resonance, A(ω) behaves as ω-3/4|ln⁡ω|. Scattering off the core hole becomes resonant in 1D and 2D in the presence of an empty subband above the Fermi level; then a deep hole splits off a level from the bottom of this subband. Fermi-edge absorption in the regime when resonant level transforms into a Kondo peak is discussed.

  1. Periodicity property of relativistic Thomson scattering with application to exact calculations of angular and spectral distributions of the scattered field

    SciTech Connect

    Popa, Alexandru

    2011-08-15

    We prove that the analytical expression of the intensity of the relativistic Thomson scattered field for a system composed of an electron interacting with a plane electromagnetic field can be written in the form of a composite periodic function of only one variable, that is, the phase of the incident field. This property is proved without using any approximation in the most general case in which the field is elliptically polarized, the initial phase of the incident field and the initial velocity of the electron are taken into consideration, and the direction in which the radiation is scattered is arbitrary. This property leads to an exact method for calculating the angular and spectral distributions of the scattered field, which reveals a series of physical details of these distributions, such as their dependence on the components of the initial electron velocity. Since the phase of the field is a relativistic invariant, it follows that the periodicity property is also valid when the analysis is made in the inertial system in which the initial velocity of the electron is zero in the case of interactions between very intense electromagnetic fields and relativistic electrons. Consequently, the calculation method can be used for the evaluation of properties of backscattered hard radiations generated by this type of interaction. The theoretical evaluations presented in this paper are in good agreement with the experimental data from literature.

  2. Electron scattering from gas phase cis-diamminedichloroplatinum(II): quantum analysis of resonance dynamics.

    PubMed

    Carey, Ralph; Lucchese, Robert R; Gianturco, F A

    2013-05-28

    We present scattering calculations of electron collisions with the platinum-containing compound cis-diamminedichloroplatinum (CDDP), commonly known as cisplatin, between 0.5 eV and 6 eV, and the corresponding isolated Pt atom from 0.1 eV to 10 eV. We find evidence of resonances in e(-)-CDDP scattering, using an ab initio description of the target. We computed scattering matrix elements from equations incorporating exchange and polarization effects through the use of the static-exchange plus density functional correlation potential. Additionally, we made use of a purely local adiabatic model potential that allows Siegert eigenstates to be calculated, thereby allowing inspection of the possible resonant scattering wave functions. The total cross section for electron scattering from (5d(10)) (1)S Pt displays a large magnitude, monotonic decay from the initial collision energies, with no apparent resonance scattering features in any scattering symmetry. By contrast, the e(-)-CDDP scattering cross section shows a small feature near 3.8 eV, which results from a narrow, well localized resonance of b2 symmetry. These findings are then related to the possible electron-mediated mechanism of the action of CDDP on DNA replication as suggested by recent experiments.

  3. Electron scattering from gas phase cis-diamminedichloroplatinum(II): Quantum analysis of resonance dynamics

    NASA Astrophysics Data System (ADS)

    Carey, Ralph; Lucchese, Robert R.; Gianturco, F. A.

    2013-05-01

    We present scattering calculations of electron collisions with the platinum-containing compound cis-diamminedichloroplatinum (CDDP), commonly known as cisplatin, between 0.5 eV and 6 eV, and the corresponding isolated Pt atom from 0.1 eV to 10 eV. We find evidence of resonances in e--CDDP scattering, using an ab initio description of the target. We computed scattering matrix elements from equations incorporating exchange and polarization effects through the use of the static-exchange plus density functional correlation potential. Additionally, we made use of a purely local adiabatic model potential that allows Siegert eigenstates to be calculated, thereby allowing inspection of the possible resonant scattering wave functions. The total cross section for electron scattering from (5d10) 1S Pt displays a large magnitude, monotonic decay from the initial collision energies, with no apparent resonance scattering features in any scattering symmetry. By contrast, the e--CDDP scattering cross section shows a small feature near 3.8 eV, which results from a narrow, well localized resonance of b2 symmetry. These findings are then related to the possible electron-mediated mechanism of the action of CDDP on DNA replication as suggested by recent experiments.

  4. Enhancing detection sensitivity of metallic nanostructures by resonant coupling mode and spectral integration analysis.

    PubMed

    Lin, En-Hung; Tsai, Wan-Shao; Lee, Kuang-Li; Lee, Ming-Chang M; Wei, Pei-Kuen

    2014-08-11

    We report a simple method to efficiently improve the detection limit of surface plasmon resonance in periodic metallic nanostructures by using small angle illumination and spectral integration analysis. The large-area gold nanoslit arrays were fabricated by thermal-annealing template-stripping method with a slit width of 60 nm and period of 500 nm. The small angle illumination induced a resonant coupling between surface plasmon mode and substrate mode. It increased ~2.24 times intensity sensitivity at 5.5° incident angle. The small-angle illumination also resulted in multiple resonant peaks. The spectral integration method integrated all changes near the resonant peaks and increased the signal to noise ratio about 5 times as compared to single-wavelength intensity analysis. Combining both small angle and spectral integration, the detection limit was increased to one order of magnitude. The improvement of the detection limit for antigen-antibody interactions was demonstrated.

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

    NASA Technical Reports Server (NTRS)

    Panda, J.; Seasholtz, R. G.

    2004-01-01

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

  6. Recent measurements of the spectral backward-scattering coefficient in coastal waters

    NASA Astrophysics Data System (ADS)

    Maffione, Robert A.; Dana, David R.

    1997-02-01

    The backward scattering coefficient bb was measured in various coastal waters with fixed-angle backscattering sensors developed by the authors. Measurements were made at four discrete wavelengths covering the spectral range 440 to 675 nm. A power law spectral dependence of bb due to scattering by particles was investigated of the form bbp((lambda) ) equals bbp ((lambda) 0) ((lambda) 0/(lambda) )(gamma , where the superscript p denotes particle scattering and (lambda) is the wavelength. The exponent (gamma) depends on the particle size distribution and composition of particles. Extensive measurements in Monterey Bay, California, showed that 0.1 spectrally 'flat' waters measured.

  7. Directly Characterizing the Relative Strength and Momentum Dependence of Electron-Phonon Coupling Using Resonant Inelastic X-Ray Scattering

    NASA Astrophysics Data System (ADS)

    Devereaux, T. P.; Shvaika, A. M.; Wu, K.; Wohlfeld, K.; Jia, C. J.; Wang, Y.; Moritz, B.; Chaix, L.; Lee, W.-S.; Shen, Z.-X.; Ghiringhelli, G.; Braicovich, L.

    2016-10-01

    The coupling between lattice and charge degrees of freedom in condensed matter materials is ubiquitous and can often result in interesting properties and ordered phases, including conventional superconductivity, charge-density wave order, and metal-insulator transitions. Angle-resolved photoemission spectroscopy and both neutron and nonresonant x-ray scattering serve as effective probes for determining the behavior of appropriate, individual degrees of freedom—the electronic structure and lattice excitation, or phonon dispersion, respectively. However, each provides less direct information about the mutual coupling between the degrees of freedom, usually through self-energy effects, which tend to renormalize and broaden spectral features precisely where the coupling is strong, impacting one's ability to quantitatively characterize the coupling. Here, we demonstrate that resonant inelastic x-ray scattering, or RIXS, can be an effective tool to directly determine the relative strength and momentum dependence of the electron-phonon coupling in condensed matter systems. Using a diagrammatic approach for an eight-band model of copper oxides, we study the contributions from the lowest-order diagrams to the full RIXS intensity for a realistic scattering geometry, accounting for matrix element effects in the scattering cross section, as well as the momentum dependence of the electron-phonon coupling vertex. A detailed examination of these maps offers a unique perspective into the characteristics of electron-phonon coupling, which complements both neutron and nonresonant x-ray scattering, as well as Raman and infrared conductivity.

  8. Directly Characterizing the Relative Strength and Momentum Dependence of Electron-Phonon Coupling Using Resonant Inelastic X-Ray Scattering

    SciTech Connect

    Devereaux, T. P.; Shvaika, A. M.; Wu, K.; Wohlfeld, K.; Jia, C. J.; Wang, Y.; Moritz, B.; Chaix, L.; Lee, W. -S.; Shen, Z. -X.; Ghiringhelli, G.; Braicovich, L.

    2016-10-25

    The coupling between lattice and charge degrees of freedom in condensed matter materials is ubiquitous and can often result in interesting properties and ordered phases, including conventional superconductivity, charge-density wave order, and metal-insulator transitions. Angle-resolved photoemission spectroscopy and both neutron and nonresonant x-ray scattering serve as effective probes for determining the behavior of appropriate, individual degrees of freedom—the electronic structure and lattice excitation, or phonon dispersion, respectively. However, each provides less direct information about the mutual coupling between the degrees of freedom, usually through self-energy effects, which tend to renormalize and broaden spectral features precisely where the coupling is strong, impacting one’s ability to quantitatively characterize the coupling. Here, we demonstrate that resonant inelastic x-ray scattering, or RIXS, can be an effective tool to directly determine the relative strength and momentum dependence of the electron-phonon coupling in condensed matter systems. Using a diagrammatic approach for an eight-band model of copper oxides, we study the contributions from the lowest-order diagrams to the full RIXS intensity for a realistic scattering geometry, accounting for matrix element effects in the scattering cross section, as well as the momentum dependence of the electron-phonon coupling vertex. A detailed examination of these maps offers a unique perspective into the characteristics of electron-phonon coupling, which complements both neutron and nonresonant x-ray scattering, as well as Raman and infrared conductivity.

  9. Investigation of mixed ionospheric and fround scatter using high spectral content pulse sequences for SuperDARN radars

    NASA Astrophysics Data System (ADS)

    Spaleta, J.; Bristow, W. A.

    2013-12-01

    SuperDARN radars estimate plasma drift velocities from the Doppler shift observed on signals scattered from field-aligned density irregularities. These field-aligned density irregularities are embedded in the ionospheric plasma, and move at the same velocity as background plasma. As a result, the electromagnetic signals scattered from these irregularities are Doppler shifted. The SuperDARN radars routinely observe ionospheric scatter Doppler velocities ranging from zero to thousands of meters per second. The radars determine the Doppler shift of the ionospheric scatter by linear fitting the phase of an auto correlation function derived from the radar pulse sequence. The phase fitting technique employed assumes a single dominant velocity is present in the signal. In addition, the SuperDARN radars can also observe signals scattered from the ground. Once refracted by the ionospheric plasma and bent earthward, the radar pulses eventually reach the ground where they scatter, sending signal back to the radar. This ground-scatter signal is characterized as having a low Doppler shift and low spectral width. The SuperDARN radars are able to use these signal characteristics to discriminate the ground scatter signal from the ionospheric scatter, when regions of ground scatter are isolated from ionospheric scatter returns. The phase fitting assumption of a single dominate target can easily be violated at ranges where ground and ionospheric scatter mix together. Due to the wide elevation angle extent of the SuperDARN radar design, ground and ionospheric scatter from different propagation paths can mix together in the return signal. When this happens, the fitting algorithm attempts to fit to the dominant signal, and if ground scatter dominates, information about the ionospheric scatter at that range can be unresolved. One way to address the mix scatter situation is to use a high spectral content pulse sequence together with a spectral estimation technique. The high spectral

  10. Ultrasharp nonlinear photothermal and photoacoustic resonances and holes beyond the spectral limit.

    PubMed

    Zharov, Vladimir P

    2011-02-01

    High-resolution nonlinear laser spectroscopy based on absorption saturation, Lamb-dip and spectral hole-burning phenomena have contributed much to basic and applied photonics. Here, a laser spectroscopy based on nonlinear photothermal and photoacoustic phenomena is presented. It shows ultrasharp resonances and dips up to a few nanometres wide in broad plasmonic spectra of nanoparticles. It also demonstrates narrowing of absorption spectra of dyes and chromophores, as well as an increase in the sensitivity and resolution of the spectral hole-burning technique. This approach can permit the study of laser-nanoparticle interactions at a level of resolution beyond the spectral limits, identification of weakly absorbing spectral holes, spectral optimization of photothermal nanotherapy, measurements of tiny red and blue plasmon resonance shifts, multispectral imaging and multicolour cytometry.

  11. Ultrasharp nonlinear photothermal and photoacoustic resonances and holes beyond the spectral limit

    PubMed Central

    Zharov, Vladimir P.

    2012-01-01

    High-resolution nonlinear laser spectroscopy based on absorption saturation, Lamb-dip and spectral hole-burning phenomena have contributed much to basic and applied photonics. Here, a laser spectroscopy based on nonlinear photothermal and photoacoustic phenomena is presented. It shows ultrasharp resonances and dips up to a few nanometres wide in broad plasmonic spectra of nanoparticles. It also demonstrates narrowing of absorption spectra of dyes and chromophores, as well as an increase in the sensitivity and resolution of the spectral hole-burning technique. This approach can permit the study of laser-nanoparticle interactions at a level of resolution beyond the spectral limits, identification of weakly absorbing spectral holes, spectral optimization of photothermal nanotherapy, measurements of tiny red and blue plasmon resonance shifts, multispectral imaging and multicolour cytometry. PMID:25558274

  12. Spectral element method-based parabolic equation for EM-scattering problems

    NASA Astrophysics Data System (ADS)

    He, Zi; Fan, Zhen-Hong; Chen, Ru-Shan

    2016-01-01

    The traditional parabolic equation (PE) method is based on the finite difference (FD) scheme. However, the scattering object cannot be well approximated for complex geometries. As a result, a large number of meshes are needed to discretize the complex scattering objects. In this paper, the spectral element method is introduced to better approximate the complex geometry in each transverse plane, while the FD scheme is used along the paraxial direction. This proposed algorithm begins with expanding the reduced scattered fields with the Gauss-Lobatto-Legendre polynomials and testing them by the Galerkin's method in each transverse plane. Then, the calculation can be taken plane by plane along the paraxial direction. Numerical results demonstrate that the accuracy can be improved by the proposed method with larger meshes when compared with the traditional PE method.

  13. The complex ion structure of warm dense carbon measured by spectrally resolved x-ray scattering

    SciTech Connect

    Kraus, D.; Barbrel, B.; Falcone, R. W.; Vorberger, J.; Helfrich, J.; Frydrych, S.; Ortner, A.; Otten, A.; Roth, F.; Schaumann, G.; Schumacher, D.; Siegenthaler, K.; Wagner, F.; Roth, M.; Gericke, D. O.; Wünsch, K.; Bachmann, B.; Döppner, T.; Bagnoud, V.; Blažević, A.; and others

    2015-05-15

    We present measurements of the complex ion structure of warm dense carbon close to the melting line at pressures around 100 GPa. High-pressure samples were created by laser-driven shock compression of graphite and probed by intense laser-generated x-ray sources with photon energies of 4.75 keV and 4.95 keV. High-efficiency crystal spectrometers allow for spectrally resolving the scattered radiation. Comparing the ratio of elastically and inelastically scattered radiation, we find evidence for a complex bonded liquid that is predicted by ab-initio quantum simulations showing the influence of chemical bonds under these conditions. Using graphite samples of different initial densities we demonstrate the capability of spectrally resolved x-ray scattering to monitor the carbon solid-liquid transition at relatively constant pressure of 150 GPa. Showing first single-pulse scattering spectra from cold graphite of unprecedented quality recorded at the Linac Coherent Light Source, we demonstrate the outstanding possibilities for future high-precision measurements at 4th Generation Light Sources.

  14. Spectral theory of a surface-corrugated electron waveguide: The exact scattering-operator approach

    NASA Astrophysics Data System (ADS)

    Makarov, N. M.; Moroz, A. V.

    1999-07-01

    We apply the exact surface scattering operator to solve the problem of scalar (electron or sound) wave propagation through a strip with absolutely soft randomly rough boundaries. This approach is nonperturbative in either roughness heights or slopes. We analyzed the roughness-induced dephasing and attenuation of waves both asymptotically and numerically. The analysis proves that the signal is always scattered most effectively into the ``resonant'' waveguide modes, whose transverse wavelength is comparable to the rms roughness height ζ and whose total number is proportional to ζ-1. According to this integral resonance rule, the dephasing dominates over the attenuation and shows a nonanalytic (square-root) dependence on the dispersion ζ2 when (kζ)2<<1 (k is the wave number). In the case (kζ)2>>1, the dephasing and attenuation may well compete. We predict another two surprising effects: reentrant transparency and increase of the phase velocity of the wave.

  15. Scattering operators for E1-E2 x-ray resonant diffraction

    NASA Astrophysics Data System (ADS)

    Marri, Ivan; Carra, Paolo

    2004-03-01

    Resonant x-ray diffraction in noncentrosymmetric crystals is studied by considering E1-E2 processes in the fast-collision approximation. The scattering amplitude is expressed in terms of polar and magnetoelectric operators of the valence states, which are involved in the resonance. Near-edge Bragg peaks from ferroelectric, antiferroelectric, and magnetoelectric structures are predicted.

  16. Surface-enhanced resonance Raman scattering (SERRS) simulates PCR for sensitive DNA detection.

    PubMed

    Zhou, Haibo; Lin, Shenyu; Nie, Yichu; Yang, Danting; Wang, Qiqin; Chen, Weijia; Huang, Ning; Jiang, Zhengjin; Chen, Shanze

    2015-11-21

    This paper describes a novel double-stranded DNA detection method through resonance between SYBR Green I and DNA with the surface-enhanced resonance Raman scattering (SERRS) assay, which opens an avenue to the quantitative and reliable application of SERRS in DNA detection.

  17. Resonant bound-free contributions to Thomson scattering of X-rays by warm dense matter

    NASA Astrophysics Data System (ADS)

    Johnson, W. R.; Nilsen, J.; Cheng, K. T.

    2013-09-01

    Recent calculations [Nilsen et al. arXiv:1212.5972] predict that contributions to the scattered photon spectrum from 3s and 3p bound states in chromium (Z = 24) at metallic density and T = 12 eV resonate below the respective bound-state thresholds. These resonances are shown to be closely related to continuum lowering, where 3d bound states in the free atom dissolve into a resonant l = 2 partial wave in the continuum. The resulting d-state resonance dominates contributions to the bound-free dynamic structure function, leading to the predicted resonances in the scattered X-ray spectrum. Similar resonant features are shown to occur in all elements in the periodic table between Ca and Mn (20 ≤ Z ≤ 25).

  18. Plasmonic resonance scattering from silver nanowire illuminated by tightly focused singular beam.

    PubMed

    Normatov, Alexander; Spektor, Boris; Leviatan, Yehuda; Shamir, Joseph

    2010-08-15

    We investigate scattering features of tightly focused singular beams by placing a cylindrical nanowire in the vicinity of a line phase singularity. Applying an illumination wavelength corresponding to silver cylinder plasmonic resonance, we compare the scattering response with that of a perfect conductor. The rigorous modeling employs a 2D version of the Richards-Wolf focusing method and the source model technique. It is found that a cylinder with a plasmonic resonance produces a strong scattering response by deflecting the power flow toward the optical singularity region, where otherwise the power approaches zero.

  19. 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.

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

    PubMed

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

    2009-09-15

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

  1. Resonance Raman scattering from Cd1-xZnxS nanoparticles dispersed in oxide glass

    NASA Astrophysics Data System (ADS)

    Arora, Akhilesh K.; Rajalakshmi, M.

    2000-11-01

    Resonance Raman scattering from 1 and 2 LO phonons is investigated from Cd1-xZnxS nanoparticles dispersed in oxide glass before and after annealing. The resonance profiles are found to exhibit asymmetry which is attributed to the interference effects arising from a nonresonant contribution to the polarizability. The energies of the resonances are found to be consistent with the direct interband transition energies estimated from the reported optical data.

  2. Point dipole and quadrupole scattering approximation to collectively responding resonator systems

    NASA Astrophysics Data System (ADS)

    Watson, Derek W.; Jenkins, Stewart D.; Ruostekoski, Janne

    2017-07-01

    We develop a theoretical formalism for collectively responding point scatterers where the radiating electromagnetic fields from each emitter are considered in the electric dipole, magnetic dipole, and electric quadrupole approximation. The contributions of the electric quadrupole moment to electromagnetically-mediated interactions between the scatterers are derived in detail for a system where each scatterer represents a linear R L C circuit resonator, representing common metamaterial resonators in radiofrequency, microwave, and optical regimes. The resulting theory includes a closed set of equations for an ensemble of discrete resonators that are radiatively coupled to each other by propagating electromagnetic fields, incorporating potentially strong interactions and recurrent scattering processes. The effective model is illustrated and tested for examples of pairs of interacting point electric dipoles, where each pair can be qualitatively replaced by a model point emitter with different multipole radiation moments.

  3. Double-confocal resonator for X-ray generation via intracavity Thomson scattering

    SciTech Connect

    Xie, M.

    1995-12-31

    There has been a growing interest in developing compact X-ray sources through Thomson scattering of a laser beam by a relativistic electron beam. For higher X-ray flux it is desirable to have the scattering to occur inside an optical resonator where the laser power is higher. In this paper I propose a double-confocal resonator design optimized for head-on Thomson scattering inside an FEL oscillator and analyze its performance taking into account the diffraction and FEL gain. A double confocal resonator is equivalent to two confocal resonators in series. Such a resonator has several advantages: it couples electron beam through and X-ray out of the cavity with holes on cavity mirrors, thus allowing the system to be compact; it supports the FEL mode with minimal diffraction loss through the holes; it provides a laser focus in the forward direction for a better mode overlap with the electron beam; and it provides a focus at the same location in the backward direction for higher Thomson scattering efficiency; in addition, the mode size at the focal point and hence the Rayleigh range can be adjusted simply through intracavity apertures; furthermore, it gives a large mode size at the mirrors to reduce power loading. Simulations as well as analytical results will be presented. Also other configurations of intracavity Thomson scattering where the double-confocal resonator could be useful will be discussed.

  4. Intermediate resonance of inelastic 12C + 12C scattering

    NASA Astrophysics Data System (ADS)

    Osamu, Tanimura

    1980-01-01

    The intermediate resonances observed in the inelastic 12C + 12C cross sections to the single and mutual 2 1+(4.43 MeV) excitations and the single 3 1- (9.64 MeV) excitation are studied by the coupled-channel method with the use of the coupling interaction derived by the folding procedure between 12C and 12C. It is shown that the model is successful in reproducing the gross structures of the inelastic cross sections and especially the correlated resonance energies of the inelastic channels. The inelastic resonances are shown to be due to the molecular resonances in an adiabatic potential between two 12C, which reproduces correctly the coupled channel resonances.

  5. Observation of narrow isotopic optical magnetic resonances in individual emission spectral lines of neon

    SciTech Connect

    Saprykin, E G; Sorokin, V A; Shalagin, A M

    2015-07-31

    Narrow resonances are observed in the course of recording the individual emission lines of the glow discharge in the mixture of isotopes {sup 20}Ne and {sup 22}Ne, depending on the strength of the longitudinal magnetic field. The position of resonances in the magnetic scale corresponds to the compensation of the isotopic shift for certain spectral lines due to the Zeeman effect. It is found that the contrast of the resonances is higher for the transitions between the highly excited energy levels, and the resonances themselves are formed in the zone of longitudinal spatial nonuniformity of the magnetic field. (laser applications and other topics in quantum electronics)

  6. Spectral characteristics of the microfiber MZ interferometer with a knot resonator

    NASA Astrophysics Data System (ADS)

    Liao, Yipeng; Wang, Jing; Wang, Shanshan; Yang, Hongjuan; Wang, Xin

    2017-04-01

    This paper investigates the transmission spectral characteristics of microfiber MZ interferometer with a knot resonator (MZIKR). The MZIKR exhibits a combined effect of resonance and interference in its transmission spectra. By adjusting the coupling coefficients to convert the relative strength of resonance and interference, the transmission spectra show various shapes, mainly reflected in the direction of fringes. The obtained upward fringe exhibits an extinction ratio of 17 dB and a FWHM of 0.3 nm. The tunable transmission spectrum demonstrated here may have great potential for narrow-band filtering, and the coexisting resonance and interference effect also allows the MZIKR to perform dual-parameters sensing.

  7. Spectral and resonance properties of the Smilansky Hamiltonian

    NASA Astrophysics Data System (ADS)

    Exner, Pavel; Lotoreichik, Vladimir; Tater, Miloš

    2017-02-01

    We analyze the Hamiltonian proposed by Smilansky to describe irreversible dynamics in quantum graphs and studied further by Solomyak and others. We derive a weak-coupling asymptotics of the ground state and add new insights by finding the discrete spectrum numerically in the subcritical case. Furthermore, we show that the model then has a rich resonance structure.

  8. Controllable scattering of photons in a one-dimensional resonator waveguide

    NASA Astrophysics Data System (ADS)

    Sun, C. P.; Zhou, L.; Gong, Z. R.; Liu, Y. X.; Nori, F.

    2009-03-01

    We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. [4pt] L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons in a 1D resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). URL: http://link.aps.org/abstract/PRL/v101/e100501

  9. Resonant nuclear scattering of synchrotron radiation: Detector development and specular scattering from a thin layer of {sup 57}Fe

    SciTech Connect

    Baron, A.Q.R.

    1995-04-01

    This thesis explores resonant nudear scattering of synchrotron radiation. An introductory chapter describes some useful concepts, such as speedup and coherent enhancement, in the context of some basic physical principles. Methods of producing highly monochromatic synchrotron beams usmg either electronic or nuclear scattering are also discussed. The body of the thesis concentrates on detector development and specular scattering from iynthetic layered materials. A detector employing n-dcrochannel plate electron multipliers is shown to have good ({approximately}50%) effidency for detecting 14.4 key x-rays incident at small ({approximately}0.5 degree) grazing angles onto Au or CsI photocathodes. However, being complicated to use, it was replaced with a large area (>=lan2) avalanche photodiode (APD) detector. The APD`s are simpler to use and have comparable (30--70%) efficiencies at 14.4 key, subnanosecond time resolution, large dynan-dc range (usable at rates up to {approximately}10{sup 8} photons/second) and low (<{approximately}0.01 cts/sec) background rates. Maxwell`s equations are used to derive the specular x-ray reflectivity of layered materials with resonant transitions and complex polarization dependencies. The effects of interfadal roughness are treated with some care, and the distorted wave Born approximation (DWBA) used to describe electronic scattering is generalized to the nuclear case. The implications of the theory are discussed in the context of grazing incidence measurements with emphasis on the kinematic and dynamical aspects of the scattering.

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  11. Voigt spectral profiles in two-photon resonance fluorescence

    SciTech Connect

    Alexanian, Moorad; Bose, Subir K.

    2007-11-15

    A recent work on two-photon fluorescence is extended by considering the pump field to be a coherent state, which represents a laser field operating well above threshold. The dynamical conditions are investigated under which the two-photon spectrum gives rise, in addition to a Lorentzian line shape at the pump frequency, to two Voigt spectral sideband profiles. Additional conditions are found under which the Voigt profile behaves like either a Gaussian or a Lorentzian line shape.

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

    PubMed

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

    2013-12-01

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

  13. Perturbative theory and modeling of electronic-resonance-enhanced coherent anti-Stokes Raman scattering spectroscopy of nitric oxide

    NASA Astrophysics Data System (ADS)

    Kuehner, Joel P.; Naik, Sameer V.; Kulatilaka, Waruna D.; Chai, Ning; Laurendeau, Normand M.; Lucht, Robert P.; Scully, Marlan O.; Roy, Sukesh; Patnaik, Anil K.; Gord, James R.

    2008-05-01

    A theory is developed for three-laser electronic-resonance-enhanced (ERE) coherent anti-Stokes Raman scattering (CARS) spectroscopy of nitric oxide (NO). A vibrational Q-branch Raman polarization is excited in the NO molecule by the frequency difference between visible Raman pump and Stokes beams. An ultraviolet probe beam is scattered from the induced Raman polarization to produce an ultraviolet ERE-CARS signal. The frequency of the ultraviolet probe beam is selected to be in electronic resonance with rotational transitions in the AΣ+2←XΠ2 (1,0) band of NO. This choice results in a resonance between the frequency of the ERE-CARS signal and transitions in the (0,0) band. The theoretical model for ERE-CARS NO spectra has been developed in the perturbative limit. Comparisons to experimental spectra are presented where either the probe laser was scanned with fixed Stokes frequency or the Stokes laser was scanned with fixed probe frequency. At atmospheric pressure and an NO concentration of 100ppm, good agreement is found between theoretical and experimental spectral peak locations and relative intensities for both types of spectra. Factors relating to saturation in the experiments are discussed, including implications for the theoretical predictions.

  14. An immunonanogold resonance scattering-quenching probe for rapid and sensitive assay of microalbumin.

    PubMed

    Jiang, Zhi-Liang; Huang, Yu-Juan; Liang, Ai-Hui

    2008-03-01

    A novel and sensitive immunonanogold resonance scattering (RS) spectral probe was obtained for rapid detection of microalbumin (Malb), using 10 nm gold nanaoparticle to label goat anti-human Malb. It was based on that the gold-labeled anti-Malb took place nonspecific aggregation and exhibited a strong RS peak at 577 nm in pH 5.2 C(6)H(8)O(7)-Na(2)HPO(4) buffer solution containing polyethylene glycol (PEG), and the immunocomplex formed after specific reaction of gold-labeled anti-Malb with Malb, which led to a decrease in the intensity of RS peak at 577 nm considerably. The decreased RS intensity at 577 nm (DeltaI (577nm)) was linear to the concentration of Malb in the range of 4-128 ng/mL, with a detection limit of 3.2 ng/mL. The proposed method was applied to detect Malb in healthy human urine samples with satisfactory results.

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

    PubMed

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

    2006-05-01

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

  16. Determination of nucleic acids with a near infrared cyanine dye using resonance light scattering technique

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Zheng, Hong; Li, Ling; Wu, Yuqin; Chen, Jinlong; Zhuo, Shujuan; Zhu, Changqing

    2006-06-01

    A new method for the determination of nucleic acids has been developed based on the enhancement effect of resonance light scattering (RLS) with a cationic near infrared (NIR) cyanine dye. Under the optimal conditions, the enhanced RLS intensity at 823 nm is proportional to the concentration of nucleic acids in the range of 0-400 ng mL -1 for both calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA), 0-600 ng mL -1 for snake ovum RNA (SO RNA). The detection limits are 3.5 ng mL -1, 3.4 ng mL -1 and 2.9 ng mL -1 for CT DNA, FS DNA and SO RNA, respectively. Owing to performing in near infrared region, this method not only has high sensitivity endowed by RLS technique but also avoids possible spectral interference from background. It has been applied to the determination of nucleic acids in synthetic and real samples and satisfactory results were obtained.

  17. Spectrally resolving and scattering-compensated x-ray luminescence/fluorescence computed tomography

    PubMed Central

    Cong, Wenxiang; Shen, Haiou; Wang, Ge

    2011-01-01

    The nanophosphors, or other similar materials, emit near-infrared (NIR) light upon x-ray excitation. They were designed as optical probes for in vivo visualization and analysis of molecular and cellular targets, pathways, and responses. Based on the previous work on x-ray fluorescence computed tomography (XFCT) and x-ray luminescence computed tomography (XLCT), here we propose a spectrally-resolving and scattering-compensated x-ray luminescence/fluorescence computed tomography (SXLCT or SXFCT) approach to quantify a spatial distribution of nanophosphors (other similar materials or chemical elements) within a biological object. In this paper, the x-ray scattering is taken into account in the reconstruction algorithm. The NIR scattering is described in the diffusion approximation model. Then, x-ray excitations are applied with different spectra, and NIR signals are measured in a spectrally resolving fashion. Finally, a linear relationship is established between the nanophosphor distribution and measured NIR data using the finite element method and inverted using the compressive sensing technique. The numerical simulation results demonstrate the feasibility and merits of the proposed approach. PMID:21721815

  18. A conservative spectral method for the Boltzmann equation with anisotropic scattering and the grazing collisions limit

    SciTech Connect

    Gamba, Irene M.; Haack, Jeffrey R.

    2014-08-01

    We present the formulation of a conservative spectral method for the Boltzmann collision operator with anisotropic scattering cross-sections. The method is an extension of the conservative spectral method of Gamba and Tharkabhushanam [17,18], which uses the weak form of the collision operator to represent the collisional term as a weighted convolution in Fourier space. The method is tested by computing the collision operator with a suitably cut-off angular cross section and comparing the results with the solution of the Landau equation. We analytically study the convergence rate of the Fourier transformed Boltzmann collision operator in the grazing collisions limit to the Fourier transformed Landau collision operator under the assumption of some regularity and decay conditions of the solution to the Boltzmann equation. Our results show that the angular singularity which corresponds to the Rutherford scattering cross section is the critical singularity for which a grazing collision limit exists for the Boltzmann operator. Additionally, we numerically study the differences between homogeneous solutions of the Boltzmann equation with the Rutherford scattering cross section and an artificial cross section, which give convergence to solutions of the Landau equation at different asymptotic rates. We numerically show the rate of the approximation as well as the consequences for the rate of entropy decay for homogeneous solutions of the Boltzmann equation and Landau equation.

  19. Coded aperture coherent scatter spectral imaging for assessment of breast cancers: an ex-vivo demonstration

    NASA Astrophysics Data System (ADS)

    Spencer, James R.; Carter, Joshua E.; Leung, Crystal K.; McCall, Shannon J.; Greenberg, Joel A.; Kapadia, Anuj J.

    2017-03-01

    A Coded Aperture Coherent Scatter Spectral Imaging (CACSSI) system was developed in our group to differentiate cancer and healthy tissue in the breast. The utility of the experimental system was previously demonstrated using anthropomorphic breast phantoms and breast biopsy specimens. Here we demonstrate CACSSI utility in identifying tumor margins in real time using breast lumpectomy specimens. Fresh lumpectomy specimens were obtained from Surgical Pathology with the suspected cancerous area designated on the specimen. The specimens were scanned using CACSSI to obtain spectral scatter signatures at multiple locations within the tumor and surrounding tissue. The spectral reconstructions were matched with literature form-factors to classify the tissue as cancerous or non-cancerous. The findings were then compared against pathology reports to confirm the presence and location of the tumor. The system was found to be capable of consistently differentiating cancerous and healthy regions in the breast with spatial resolution of 5 mm. Tissue classification results from the scanned specimens could be correlated with pathology results. We now aim to develop CACSSI as a clinical imaging tool to aid breast cancer assessment and other diagnostic purposes.

  20. Spectral fluorescence and scattering of cyanobacteria and diatoms held by optical tweezers

    NASA Astrophysics Data System (ADS)

    Sonek, Gregory J.; Liu, Yagang; Iturriaga, Rodolfo H.

    1994-10-01

    Optical tweezers is a term used to describe the optical force generation and confinement process by a highly focused laser beam. The forces exerted by the tweezer are sufficient to confine and move cells and particles without physical contact. When integrated with fluorescence or scattering detection, the laser tweezer can become a powerful instrument for the rapid characterization of the optical properties of isolated organic marine particulates and phytoplanktonic cells, from which bulk properties may be inferred. This technique offers the advantage of studying planktonic cells and organisms in their natural environment by confinement without immobilization, thereby preserving the spectral absorption and fluorescence properties of the samples under study. Herein, we report, for the first time, on the measurement of the spectral fluorescence and scattering of cyanobacteria and diatoms which have been confined by an optical tweezer. Preliminary data shows the characteristic emission peak from the chlorophyll (alpha) pigment (685 nm) for both samples, as well as spectral features that may be related to other photosynthetic pigments.

  1. Collisionless spectral-kinetic Simulation of the Multipole Resonance Probe

    NASA Astrophysics Data System (ADS)

    Dobrygin, Wladislaw; Szeremley, Daniel; Schilling, Christian; Oberrath, Jens; Eremin, Denis; Mussenbrock, Thomas; Brinkmann, Ralf Peter

    2012-10-01

    Plasma resonance spectroscopy is a well established plasma diagnostic method realized in several designs. One of these designs is the multipole resonance probe (MRP). In its idealized - geometrically simplified - version it consists of two dielectrically shielded, hemispherical electrodes to which an RF signal is applied. A numerical tool is under development, which is capable of simulating the dynamics of the plasma surrounding the MRP in electrostatic approximation. In the simulation the potential is separeted in an inner and a vacuum potential. The inner potential is influenced by the charged partilces and is calculated by a specialized Poisson solver. The vacuum potential fulfills Laplace's equetion and consists of the applied voltage of the probe as boundary condition. Both potentials are expanded in spherical harmonics. For a practical particle pusher implementation, the expansion must be appropriately truncated. Compared to a PIC simulation a grid is unnecessary to calculate the force on the particles. This work purpose is a collisionless kinetic simulation, which can be used to investigate kinetic effects on the resonance behavior of the MRP.[4pt] [1] M. Lapke et al., Appl. Phys. Lett. 93, 2008, 051502.

  2. Resonances in positron-hydrogen scattering in dense quantum plasmas

    SciTech Connect

    Jiang, Zishi; Zhang, Yong-Zhi; Kar, Sabyasachi

    2015-05-15

    We have investigated the S-wave resonance states in positron-hydrogen system embedded in dense quantum plasmas using Hylleraas-type wave functions within the framework of the stabilization method. The effect of quantum plasmas has been incorporated using the exponential-cosine-screened Coulomb (modified Yukawa-type) potential. Resonance parameters (both position and width) below the Ps n = 2 threshold are reported as functions of plasma screening parameters.

  3. Surface plasmon resonance scattered by a dielectric sphere

    NASA Astrophysics Data System (ADS)

    Hong, Xin; Yin, Xuejie

    2016-11-01

    It is well known that when total internal reflection occurs at the interface between high to low refractive index, evanescent field will go into the media with low refractive index. This field can be scattered by a small dielectric particle on the surface. In this paper, with the aim to enhance the scattering field we introduced a thin gold film, the filed modified by the metallic film was theoretically calculated by FDTD solver. Further a polystyrene bead at the diameter of 200nm and 800nm was employed to test the model. Theoretical and experimental results agree well with each other that the locally excitated surface plasmon play a dominant role in the field enhancement scattered by the sphere.

  4. Integrated spectral and image analysis of hyperspectral scattering data for prediction of apple fruit firmness and soluble solids content

    USDA-ARS?s Scientific Manuscript database

    Spectral scattering is useful for assessing the firmness and soluble solids content (SSC) of apples. In previous research, mean reflectance extracted from the hyperspectral scattering profiles was used for this purpose since the method is simple and fast and also gives relatively good predictions. T...

  5. Electronic excitations in the correlated metal BaV(0.98)Ti(0.02)S(3) studied using resonant inelastic soft x-ray scattering.

    PubMed

    Learmonth, T; Glans, P-A; Guo, J-H; Greenblatt, M; Smith, K E

    2010-01-20

    Electronic excitations in the correlated metal BaTi(0.02)V(0.98)S(3) have been studied using resonant inelastic soft x-ray scattering at the V L edge. The intensities of the intra-atomic d-d(*) excitations and the elastic x-ray scattering feature are found to be temperature dependent, with the intensity increasing with decreasing temperature until saturation is reached near 100 K. The behavior of the spectral features is interpreted as evidence of a shift in the 3d electrons from more band-like states at higher temperature to more localized states at low temperature.

  6. Electronic excitations in the correlated metal BaV0.98Ti0.02S3 studied using resonant inelastic soft x-ray scattering

    NASA Astrophysics Data System (ADS)

    Learmonth, T.; Glans, P.-A.; Guo, J.-H.; Greenblatt, M.; Smith, K. E.

    2010-01-01

    Electronic excitations in the correlated metal BaTi0.02V0.98S3 have been studied using resonant inelastic soft x-ray scattering at the V L edge. The intensities of the intra-atomic d-d* excitations and the elastic x-ray scattering feature are found to be temperature dependent, with the intensity increasing with decreasing temperature until saturation is reached near 100 K. The behavior of the spectral features is interpreted as evidence of a shift in the 3d electrons from more band-like states at higher temperature to more localized states at low temperature.

  7. Tunneling effects in resonant acoustic scattering of an air bubble in unbounded water.

    PubMed

    Simão, André G; Guimarães, Luiz G

    2016-01-01

    The problem of acoustic scattering of a gaseous spherical bubble immersed within unbounded liquid surrounding is considered in this work. The theory of partial wave expansion related to this problem is revisited. A physical model based on the analogy between acoustic scattering and potential scattering in quantum mechanics is proposed to describe and interpret the acoustical natural oscillation modes of the bubble, namely, the resonances. In this context, a physical model is devised in order to describe the air water interface and the implications of the high density contrast on the various regimes of the scattering resonances. The main results are presented in terms of resonance lifetime periods and quality factors. The explicit numerical calculations are undertaken through an asymptotic analysis considering typical bubble dimensions and underwater sound wavelengths. It is shown that the resonance periods are scaled according to the Minnaert's period, which is the short lived resonance mode, called breathing mode of the bubble. As expected, resonances with longer lifetimes lead to impressive cavity quality Q-factor ranging from 1010 to 105. The present theoretical findings lead to a better understanding of the energy storage mechanism in a bubbly medium.

  8. Revival resonant scattering, perfect caustics, and isotropic transport of pseudospin-1 particles

    NASA Astrophysics Data System (ADS)

    Xu, Hong-Ya; Lai, Ying-Cheng

    2016-10-01

    We report unusual physics associated with wave scattering in pseudospin-1 systems whose band structure consists of a conventional Dirac cone and a topologically flat band. First, for small scatterer size, we find a surprising revival resonant scattering phenomenon and identify a peculiar type of boundary trapping profile through the formation of unusual vortices as the physical mechanism. Second, for larger scatterer size, a perfect caustic phenomenon arises as a manifestation of the super-Klein tunneling effect, leading to the scatterer's being effectively as a Veselago lens. Third, in the far scattering field, an unexpected isotropic behavior emerges at low energies, which can be attributed to the vanishing Berry phase for massless pseudospin-1 particles and, consequently, to constructive interference between the time-reversed backscattering paths. We develop an analytic theory based on the generalized Dirac-Weyl equation to fully explain these phenomena and articulate experimental schemes with photonic or electronic systems.

  9. Local normal vector field formulation for periodic scattering problems formulated in the spectral domain.

    PubMed

    van Beurden, M C; Setija, I D

    2017-02-01

    We present two adapted formulations, one tailored to isotropic media and one for general anisotropic media, of the normal vector field framework previously introduced to improve convergence near arbitrarily shaped material interfaces in spectral simulation methods for periodic scattering geometries. The adapted formulations enable the definition and generation of the normal vector fields to be confined to a region of prolongation that includes the material interfaces but is otherwise limited. This allows for a more flexible application of geometrical transformations like rotation and translation per scattering object in the unit cell. Moreover, these geometrical transformations enable a cut-and-connect strategy to compose general geometries from elementary building blocks. The entire framework gives rise to continuously parameterized geometries.

  10. Time-stretched spectrally encoded angular light scattering for high-throughput real-time diagnostics

    NASA Astrophysics Data System (ADS)

    Adam, Jost; Mahjoubfar, Ata; Diebold, Eric D.; Buckley, Brandon W.; Jalali, Bahram

    2014-05-01

    The angular light scattering profile of microscopic particles significantly depends on their morphological parameters, such as size and shape. This dependency is widely used in state-of-the-art flow cytometry methods for particle classification. We recently introduced the spectrally encoded angular light scattering (SEALS) method, with potential application in scanning flow cytometry (SFC). We show that a one-to-one wavelength-to-angle mapping enables the measurement of the angular dependence of scattered light from microscopic particles over a wide dynamic range. Improvement in dynamic range is obtained by equalizing the angular scattering dependence via spectral equalization. The resulting continuous angular spectrum is obtained without mechanical scanning, enabling single-shot measurement. Using this information, particle morphology can be determined with improved accuracy. We derive and experimentally verify an analytic wavelength-to-angle mapping model, facilitating rapid data processing. As a proof of concept, we demonstrate the method's capability of distinguishing differently sized polystyrene beads. The combination of SEALS with time-stretch dispersive Fourier transform (TS-DFT) offers real-time and high-throughput (high frame rate) measurements and renders the method suitable for integration in standard flow cytometers: By transforming the spectrum into time and slowing the time scale, using group velocity dispersion (GVD), single-shot spectra can be obtained at high throughput, using a photodiode and a real-time digitizer. The amount of group velocity dispersion is chosen to time-stretch the optical pulses, that is, to slow them down, such that they do not overlap and may be digitized in real-time.

  11. Time-lens Based Hyperspectral Stimulated Raman Scattering Imaging and Quantitative Spectral Analysis

    PubMed Central

    Wang, Ke; Zhang, Delong; Charan, Kriti; Slipchenko, Mikhail N.; Wang, Ping; Xu, Chris; Cheng, Ji-Xin

    2014-01-01

    We demonstrate a hyperspectral stimulated Raman scattering (SRS) microscope through spectral-transformed excitation. The 1064-nm Stokes pulse was from a synchronized time-lens source, generated through time-domain phase modulation of a continuous wave (CW) laser. The tunable pump pulse was from linear spectral filtering of a femtosecond laser output with an intra-pulse spectral scanning pulse shaper. By electronically modulating the time-lens source at 2.29 MHz, hyperspectral stimulated Raman loss (SRL) images were obtained on a laser-scanning microscope. Using this microscope, DMSO in aqueous solution with a concentration down to 28 mM could be detected at 2 μs time constant. Hyper-spectral SRL images of prostate cancer cells were obtained. Multivariate curve resolution analysis was further applied to decompose the SRL images into concentration maps of CH2 and CH3 bonds. This method offers exciting potential in label-free imaging of live cells using fingerprint Raman bands. Hyperspectral SRS microscopy using a synchronized time-lens source allows mapping of different cellular contents. PMID:23840041

  12. Single shot, double differential spectral measurements of inverse Compton scattering in the nonlinear regime

    NASA Astrophysics Data System (ADS)

    Sakai, Y.; Gadjev, I.; Hoang, P.; Majernik, N.; Nause, A.; Fukasawa, A.; Williams, O.; Fedurin, M.; Malone, B.; Swinson, C.; Kusche, K.; Polyanskiy, M.; Babzien, M.; Montemagno, M.; Zhong, Z.; Siddons, P.; Pogorelsky, I.; Yakimenko, V.; Kumita, T.; Kamiya, Y.; Rosenzweig, J. B.

    2017-06-01

    Inverse Compton scattering (ICS) is a unique mechanism for producing fast pulses—picosecond and below—of bright photons, ranging from x to γ rays. These nominally narrow spectral bandwidth electromagnetic radiation pulses are efficiently produced in the interaction between intense, well-focused electron and laser beams. The spectral characteristics of such sources are affected by many experimental parameters, with intense laser effects often dominant. A laser field capable of inducing relativistic oscillatory motion may give rise to harmonic generation and, importantly for the present work, nonlinear redshifting, both of which dilute the spectral brightness of the radiation. As the applications enabled by this source often depend sensitively on its spectra, it is critical to resolve the details of the wavelength and angular distribution obtained from ICS collisions. With this motivation, we present an experimental study that greatly improves on previous spectral measurement methods based on x-ray K -edge filters, by implementing a multilayer bent-crystal x-ray spectrometer. In tandem with a collimating slit, this method reveals a projection of the double differential angular-wavelength spectrum of the ICS radiation in a single shot. The measurements enabled by this diagnostic illustrate the combined off-axis and nonlinear-field-induced redshifting in the ICS emission process. The spectra obtained illustrate in detail the strength of the normalized laser vector potential, and provide a nondestructive measure of the temporal and spatial electron-laser beam overlap.

  13. Single shot, double differential spectral measurements of inverse Compton scattering in the nonlinear regime

    DOE PAGES

    Sakai, Y.; Gadjev, I.; Hoang, P.; ...

    2017-06-05

    Inverse Compton scattering (ICS) is a unique mechanism for producing fast pulses$-$picosecond and below$-$of bright photons, ranging from x to γ rays. These nominally narrow spectral bandwidth electromagnetic radiation pulses are efficiently produced in the interaction between intense, well-focused electron and laser beams. The spectral characteristics of such sources are affected by many experimental parameters, with intense laser effects often dominant. A laser field capable of inducing relativistic oscillatory motion may give rise to harmonic generation and, importantly for the present work, nonlinear redshifting, both of which dilute the spectral brightness of the radiation. As the applications enabled by thismore » source often depend sensitively on its spectra, it is critical to resolve the details of the wavelength and angular distribution obtained from ICS collisions. With this motivation, we present an experimental study that greatly improves on previous spectral measurement methods based on x-ray K -edge filters, by implementing a multilayer bent-crystal x-ray spectrometer. In tandem with a collimating slit, this method reveals a projection of the double differential angular-wavelength spectrum of the ICS radiation in a single shot. The measurements enabled by this diagnostic illustrate the combined off-axis and nonlinear-field-induced redshifting in the ICS emission process. The spectra obtained illustrate in detail the strength of the normalized laser vector potential, and provide a nondestructive measure of the temporal and spatial electron-laser beam overlap.« less

  14. NONLINEAR OPTICS: Stimulated resonant hyper-Raman scattering of light by polaritons in alkali metal vapors

    NASA Astrophysics Data System (ADS)

    Galaĭchuk, Yu A.; Yashkir, Yu N.

    1989-12-01

    A theory is developed for the calculation of the gain g due to stimulated resonant hyper-Raman scattering of light by polaritons in gaseous media. It is shown that throughout the tuning range of the pump frequency (including one- and two-photon resonances) a maximum of g corresponds to a dispersion curve of polaritons plotted ignoring attenuation. Theoretical results are used to analyze characteristics of hyper-Raman scattering in sodium vapor. It is shown that under normal experimental conditions the splitting of polariton branches is considerable (amounting to tens of reciprocal centimeters on the frequency scale and several angular degrees). The value of g is estimated for two-photon resonances in the case when the pump frequency is tunable in a wide range. The optimal conditions for stimulated hyper-Raman scattering are identified.

  15. Spectroscopy of {sup 16}O Using {alpha}+{sup 12}C Resonant Scattering in Inverse Kinematics

    SciTech Connect

    Ashwood, N. I.; Freer, M.; Bloxham, T. R.; Curtis, N.; Haigh, P. J.; Price, D. L.; Achouri, N. L.; Catford, W. N.; Harlin, C. W.; Patterson, N. P.; Thomas, J. S.; Soic, N.

    2009-08-26

    A measurement of the {alpha}({sup 12}C,{alpha}){sup 12}C reaction has been performed using resonant scattering with a gas target. Beam energies of 46, 51, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6 to 22.9 MeV in {sup 16}O. The angular distributions of the elastic scattering were measured at zero degrees using an array of segmented silicon strip detectors with a minimum range of 0 deg. to 30 deg. in the centre of mass. The spins of 8 resonances between 14.1 and 18.5 MeV were obtained, confirming spin assignments made using elastic scattering in normal kinematics. An R-matrix analysis of the data was performed which indicates that the present understanding of {sup 16}O in this region is good, but not complete.

  16. Resonance Raman Spectra of Hemoglobin and Cytochrome c: Inverse Polarization and Vibronic Scattering

    PubMed Central

    Spiro, Thomas G.; Strekas, Thomas C.

    1972-01-01

    Resonance Raman spectra of hemoglobin and cytochrome c in dilute solution contain prominent bands that exhibit inverse polarization, i.e., the polarization vector of the incident radiation is rotated through 90° for 90° scattering, giving infinite depolarization ratios. This phenomenon is shown to require an antisymmetric molecular-scattering tensor. The antisymmetry, which is characteristic of resonance scattering, is associated with the form of a particular class of vibrations, A20, of the tetragonal heme chromophores. The dependence of the resonance Raman spectra on the wavelength of the exciting radiation, as well as their polarization properties, demonstrates that the prominent bands correspond to vibronically active modes of the first electronic transition of the heme proteins, and provide confirmation of Albrecht's vibronic theory of Raman intensities. PMID:4506783

  17. The asymptotic behaviour of the scattering matrix in a neighbourhood of the endpoints of a spectral gap

    NASA Astrophysics Data System (ADS)

    Nazarov, S. A.

    2017-01-01

    The behaviour of the scattering matrix is investigated as the spectral parameter approaches an endpoint of a spectral gap of a quantum waveguide from the inside or the outside. The waveguide has two sleeves, one is cylindrical and the other periodic. When the spectral parameter traverses the spectral gap, the scattering matrix is reshaped because the number of waves inside and outside the gap is different. Notwithstanding, the smaller scattering matrix (in size) is transformed continuously into an identical block in the bigger scattering matrix and, in addition, the latter takes block diagonal form in the limit at the endpoint of the gap, that is, at the spectral threshold. The unexpected phenomena are related to the other block. It is shown that in the limit this block can only take certain values at the threshold, and taking one or other of these values depends on the structure of the continuous spectrum and also on the structure of the subspace of `almost standing' waves at the threshold, which are solutions of the homogeneous problem that transfer no energy to infinity. A criterion for the existence of such solutions links the dimension of this subspace to the multiplicity of the eigenvalue -1 of the threshold scattering matrix. Asymptotic formulae are obtained, which show, in particular, that the phenomenon of anomalous scattering of high-amplitude waves at near-threshold frequencies, discovered by Weinstein in a special acoustic problem, also occurs in periodic waveguides. Bibliography: 38 titles.

  18. 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.

  19. Separation of scattering and absorption contributions in UV/visible spectra of resonant systems.

    PubMed

    Micali, N; Mallamace, F; Castriciano, M; Romeo, A; Scolaro, L M

    2001-10-15

    Resonance light scattering (RLS) is a phenomenon due to an enhancement of the scattered light in close proximity to an absorption band. The effect is easily detectable in the case of strongly absorbing chromophores, which are able to interact, thus leading to large aggregates (Pasternack, R. F.; Collings, P. J. Science 1995, 269, 935). The measurement of absorption spectra from solutions containing such resonant systems can lead to misleading results. In this paper, a simple method is described to obtain absorption spectra of aggregated species with a fairly good correction of the scattering component. The RLS spectrum, obtained using a common spectrofluorimeter, is correlated to the extinction spectrum of the same sample, allowing for an estimation of the scattering contribution to the total extinction spectrum. The method has been successfully applied both on real samples containing aggregated chromophores, such as porphyrins, chlorophyll a and gold colloids, and by simulating extinction spectra.

  20. Resonant Raman scattering theory for Kitaev models and their Majorana fermion boundary modes

    NASA Astrophysics Data System (ADS)

    Perreault, Brent; Knolle, Johannes; Perkins, Natalia B.; Burnell, F. J.

    2016-09-01

    We study the inelastic light scattering response in two- (2D) and three-dimensional (3D) Kitaev spin-liquid models with Majorana spinon band structures in the symmetry classes BDI and D leading to protected gapless surface modes. We present a detailed calculation of the resonant Raman/Brillouin scattering vertex relevant to iridate and ruthenate compounds whose low-energy physics is believed to be proximate to these spin-liquid phases. In the symmetry class BDI, we find that while the resonant scattering on thin films can detect the gapless boundary modes of spin liquids, the nonresonant processes do not couple to them. For the symmetry class D, however, we find that the coupling between both types of light-scattering processes and the low-energy surface states is strongly suppressed. Additionally, we describe the effect of weak time-reversal symmetry breaking perturbations on the bulk Raman response of these systems.

  1. Nuclear magnetic resonance spectral analysis and molecular properties of berberine

    NASA Astrophysics Data System (ADS)

    Huang, Ming-Ju; Lee, Ken S.; Hurley, Sharon J.

    An extensive theoretical study of berberine has been performed at the ab initio HF/6-31G**, HF/6-311G**, and B3LYP/6-311G** levels with and without solvent effects. The optimized structures are compared with X-ray data. We found that the optimized structures with solvent effects are in slightly better agreement with X-ray data than those without solvent effects. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of berberine were calculated by using the gauge-independent atomic orbital (GIAO) (with and without solvent effects), CSGT, and IGAIM methods. The calculated chemical shifts were compared with the two-dimensional NMR experimental data. Overall, the calculated chemical shifts show very good agreement with the experimental results. The harmonic vibrational frequencies for berberine were calculated at the B3LYP/6-311G** level.

  2. CARS Spectral Fitting with Multiple Resonant Species using Sparse Libraries

    NASA Technical Reports Server (NTRS)

    Cutler, Andrew D.; Magnotti, Gaetano

    2010-01-01

    The dual pump CARS technique is often used in the study of turbulent flames. Fast and accurate algorithms are needed for fitting dual-pump CARS spectra for temperature and multiple chemical species. This paper describes the development of such an algorithm. The algorithm employs sparse libraries, whose size grows much more slowly with number of species than a conventional library. The method was demonstrated by fitting synthetic "experimental" spectra containing 4 resonant species (N2, O2, H2 and CO2), both with noise and without it, and by fitting experimental spectra from a H2-air flame produced by a Hencken burner. In both studies, weighted least squares fitting of signal, as opposed to least squares fitting signal or square-root signal, was shown to produce the least random error and minimize bias error in the fitted parameters.

  3. Pion double charge exchange scattering above the delta resonance

    SciTech Connect

    Burleson, G.R.

    1989-01-01

    Data are presented on pion-nucleus double-charge-exchange scattering at energies between 300 and 500 MeV, the highest energies measured so far, together with a review of results at lower energies. The small-angle excitation functions disagree with predictions based on a sex-quark cluster model and on an optical model consistent with single-charge-exchange scattering at these energies, but they are consistent with a distorted-wave calculation. Data on f{sub 7/2}-shell nuclei are in partial agreement with a two-amplitude model which is successful at lower energies. In order to achieve good understanding of this process at these energies, more work; both experimental and theoretical, is needed. 16 refs., 6 figs.

  4. Resonance scattering at third-order exceptional points

    NASA Astrophysics Data System (ADS)

    Heiss, W. D.; Wunner, G.

    2015-08-01

    We analyze scattering cross sections at and near third-order exceptional points (EP3), i.e., points in physical parameter space where three energies and eigenfunctions coincide. At an EP3, the Green’s function contains a pole of third order, in addition to poles of second and first order. We show that the interference of the three pole terms produces a rich variety of line shapes at the exceptional point and in its neighbourhood. This is demonstrated by extending previous work on two harmonic oscillators to a system of three driven coupled damped oscillators. We also discuss the similarities and the differences in the behaviour of the amplitudes in the classical problem and the scattering cross sections in the quantum mechanical problem at the EP3.

  5. 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.

  6. Resonances in Coupled πK-ηK Scattering from Quantum Chromodynamics

    DOE PAGES

    Dudek, Jozef J.; Edwards, Robert G.; Thomas, Christopher E.; ...

    2014-10-01

    Using first-principles calculation within Quantum Chromodynamics, we are able to reproduce the pattern of experimental strange resonances which appear as complex singularities within coupled πK, ηK scattering amplitudes. We make use of numerical computation within the lattice discretized approach to QCD, extracting the energy dependence of scattering amplitudes through their relation- ship to the discrete spectrum of the theory in a finite-volume, which we map out in unprecedented detail.

  7. Total internal reflection resonance light scattering at solid/liquid interfaces.

    PubMed

    Tang, Yao-Ji; Chen, Ying; Yao, Min-Na; Li, Yao-Qun

    2008-08-05

    Total internal reflection (TIR) technique is an interface-specific tool and resonance light scattering (RLS) is of high sensitivity. The combination of both approaches is introduced into the solid/liquid interface for the first time. The behaviors of mixture of TPPS and BSA at the interface have been studied with total internal reflection resonance light scattering (TIR-RLS). The preliminary experimental results indicate that TIR-RLS is a good approach to study the interaction and distinguish the states of macromolecules at the solid/liquid interface.

  8. Rydberg-resolved resonant inelastic soft x-ray scattering: dynamics at core ionization thresholds.

    PubMed

    Rubensson, J-E; Söderström, J; Binggeli, C; Gråsjö, J; Andersson, J; Såthe, C; Hennies, F; Bisogni, V; Huang, Y; Olalde, P; Schmitt, T; Strocov, V N; Föhlisch, A; Kennedy, B; Pietzsch, A

    2015-04-03

    Resonant inelastic x-ray scattering spectra excited in the immediate vicinity of the core-level ionization thresholds of N2 have been recorded. Final states of well-resolved symmetry-selected Rydberg series converging to valence-level ionization thresholds with vibrational excitations are observed. The results are well described by a quasi-two-step model which assumes that the excited electron is unaffected by the radiative decay. This threshold dynamics simplifies the interpretation of resonant inelastic x-ray scattering spectra considerably and facilitates characterization of low-energy excited final states in molecular systems.

  9. Resonant scattering experiments with radioactive nuclear beams - Recent results and future plans

    SciTech Connect

    Teranishi, T.; Sakaguchi, S.; Uesaka, T.; Kubono, S.; Wakabayashi, Y.; Yamaguchi, H.; Kurihara, Y.; Bihn, D. N.; Kahl, D.; Watanabe, S.; Hashimoto, T.; Hayakawa, S.; Khiem, L. H.; Cuong, P. V.; Goto, A.

    2013-04-19

    Resonant scattering with low-energy radioactive nuclear beams of E < 5 MeV/u have been studied at CRIB of CNS and at RIPS of RIKEN. As an extension to the present experimental technique, we will install an advanced polarized proton target for resonant scattering experiments. A Monte-Carlo simulation was performed to study the feasibility of future experiments with the polarized target. In the Monte-Carlo simulation, excitation functions and analyzing powers were calculated using a newly developed R-matrix calculation code. A project of a small-scale radioactive beam facility at Kyushu University is also briefly described.

  10. Resonances in rotationally inelastic scattering of NH3 and ND3 with H2.

    PubMed

    Ma, Qianli; van der Avoird, Ad; Loreau, Jérôme; Alexander, Millard H; van de Meerakker, Sebastiaan Y T; Dagdigian, Paul J

    2015-07-28

    We present theoretical studies on the scattering resonances in rotationally inelastic collisions of NH3 and ND3 molecules with H2 molecules. We use the quantum close-coupling method to compute state-to-state integral and differential cross sections for the NH3/ND3-H2 system for collision energies between 5 and 70 cm(-1), using a previously reported potential energy surface [Maret et al., Mon. Not. R. Astron. Soc. 399, 425 (2009)]. We identify the resonances as shape or Feshbach resonances. To analyze these, we use an adiabatic bender model, as well as examination at the scattering wave functions and lifetimes. The strength and width of the resonance peaks suggest that they could be observed in a crossed molecular beam experiment involving a Stark-decelerated NH3 beam.

  11. Resonant Soft X-ray Scattering Studies of Multiferroic YMn2O5

    SciTech Connect

    Partzsch, S.; Wilkins, S.B.; Schierle, E.; Soltwisch, V.; Hill, J.P.; Weschke, E.; Souptel, D.; Buchner, B.; Geck, J.

    2011-06-17

    We performed soft x-ray resonant scattering at the MnL{sub 2,3}- and OK edges of YMn{sub 2}O{sub 5}. While the resonant intensity at the MnL{sub 2,3} edges represent the magnetic order parameter, the resonant scattering at the OK edge is found to be directly related to the macroscopic ferroelectric polarization. The latter observation reveals the important role of the spin-dependent Mn-O hybridization for the multiferroicity of YMn{sub 2}O{sub 5}. We present details about how to obtain correct energy dependent lineshapes and discuss the origin of the resonant intensity at the OK edge.

  12. A complex guided spectral transform Lanczos method for studying quantum resonance states

    DOE PAGES

    Yu, Hua-Gen

    2014-12-28

    A complex guided spectral transform Lanczos (cGSTL) algorithm is proposed to compute both bound and resonance states including energies, widths and wavefunctions. The algorithm comprises of two layers of complex-symmetric Lanczos iterations. A short inner layer iteration produces a set of complex formally orthogonal Lanczos (cFOL) polynomials. They are used to span the guided spectral transform function determined by a retarded Green operator. An outer layer iteration is then carried out with the transform function to compute the eigen-pairs of the system. The guided spectral transform function is designed to have the same wavefunctions as the eigenstates of the originalmore » Hamiltonian in the spectral range of interest. Therefore the energies and/or widths of bound or resonance states can be easily computed with their wavefunctions or by using a root-searching method from the guided spectral transform surface. The new cGSTL algorithm is applied to bound and resonance states of HO₂, and compared to previous calculations.« less

  13. A complex guided spectral transform Lanczos method for studying quantum resonance states

    SciTech Connect

    Yu, Hua-Gen

    2014-12-28

    A complex guided spectral transform Lanczos (cGSTL) algorithm is proposed to compute both bound and resonance states including energies, widths and wavefunctions. The algorithm comprises of two layers of complex-symmetric Lanczos iterations. A short inner layer iteration produces a set of complex formally orthogonal Lanczos (cFOL) polynomials. They are used to span the guided spectral transform function determined by a retarded Green operator. An outer layer iteration is then carried out with the transform function to compute the eigen-pairs of the system. The guided spectral transform function is designed to have the same wavefunctions as the eigenstates of the original Hamiltonian in the spectral range of interest. Therefore the energies and/or widths of bound or resonance states can be easily computed with their wavefunctions or by using a root-searching method from the guided spectral transform surface. The new cGSTL algorithm is applied to bound and resonance states of HO₂, and compared to previous calculations.

  14. Complementarity of resonant and nonresonant strong WW scattering at SSC and LHC

    SciTech Connect

    Chanowitz, M.S.

    1992-08-01

    Signals and backgrounds for strong WW scattering at the SSC and LHC are considered. Complementarity of resonant signals in the I = 1 WZ channel and nonresonant signals in the I = 2 W{sup +}W{sup +} channel is illustrated using a chiral lagrangian with a J = 1 ``p`` resonance. Results are presented for purely leptonic final states in the W{plus_minus}Z, W{sup +}W{sup +} + W{sup {minus}}W{sup {minus}}, and ZZ channels.

  15. Complementarity of resonant and nonresonant strong WW scattering at SSC and LHC

    SciTech Connect

    Chanowitz, M.S.

    1992-08-01

    Signals and backgrounds for strong WW scattering at the SSC and LHC are considered. Complementarity of resonant signals in the I = 1 WZ channel and nonresonant signals in the I = 2 W[sup +]W[sup +] channel is illustrated using a chiral lagrangian with a J = 1 p'' resonance. Results are presented for purely leptonic final states in the W[plus minus]Z, W[sup +]W[sup +] + W[sup [minus

  16. Structure of 10 N in 9 C+p resonance scattering

    DOE PAGES

    Hooker, J.; Rogachev, G. V.; Goldberg, V. Z.; ...

    2017-03-17

    We studied the structure of exotic nucleus 10N using 9C+p resonance scattering. Two ℓ=0 resonances were found to be the lowest states in 10N. Furthermore, the ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2) MeV depending on the 2-or 1-spin-parity assignment, and the first excited state is unbound by 2.8(2) MeV.

  17. Parameter-induced stochastic resonance based on spectral entropy and its application to weak signal detection

    SciTech Connect

    Zhang, Jinjing; Zhang, Tao

    2015-02-15

    The parameter-induced stochastic resonance based on spectral entropy (PSRSE) method is introduced for the detection of a very weak signal in the presence of strong noise. The effect of stochastic resonance on the detection is optimized using parameters obtained in spectral entropy analysis. Upon processing employing the PSRSE method, the amplitude of the weak signal is enhanced and the noise power is reduced, so that the frequency of the signal can be estimated with greater precision through spectral analysis. While the improvement in the signal-to-noise ratio is similar to that obtained using the Duffing oscillator algorithm, the computational cost reduces from O(N{sup 2}) to O(N). The PSRSE approach is applied to the frequency measurement of a weak signal made by a vortex flow meter. The results are compared with those obtained applying the Duffing oscillator algorithm.

  18. Electron spin resonance spectral analysis of irradiated royal jelly.

    PubMed

    Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

    2014-01-15

    The analysis of unpaired electron components in royal jelly was carried out using electron spin resonance (ESR) with the aim to develop a detection method for irradiated royal jelly. The ESR spectrum of royal jelly had natural signals derived from transition metals, including Fe(3+) and Cu(2+), and a signal line near g=2.00. After irradiation, a new splitting asymmetric spectrum with overall spectrum width ca. 10mT at g=2.004 was observed. The intensities of the signals at g=2.004 increased in proportion to the absorbed dose in samples under different storage conditions: fresh frozen royal jelly and dried royal jelly powder at room temperature. The signal intensity of the fresh frozen sample was stable after irradiation. One year after 10kGy irradiation of dried powder, the signal intensity was sevenfold greater than before irradiation, although the intensity continued to steadily decrease with time. This stable radiation-induced radical component was derived from the poorly soluble constituent of royal jelly.

  19. Plasmon resonant gold-coated liposomes for spectrally coded content release

    NASA Astrophysics Data System (ADS)

    Leung, Sarah J.; Troutman, Timothy S.; Romanowski, Marek

    2009-02-01

    We have recently introduced liposome-supported plasmon resonant gold nanoshells (Troutman et al., Adv. Mater. 2008, 20, 2604-2608). These plasmon resonant gold-coated liposomes are degradable into components of a size compatible with renal clearance, potentially enabling their use as multifunctional agents in applications in nanomedicine, including imaging, diagnostics, therapy, and drug delivery. The present research demonstrates that laser illumination at the wavelength matching the plasmon resonance band of a gold-coated liposome leads to the rapid release of encapsulated substances, which can include therapeutic and diagnostic agents. Leakage of encapsulated contents is monitored through the release of self-quenched fluorescein, which provides an increase in fluorescence emission upon release. Moreover, the resonant peak of these gold-coated liposomes is spectrally tunable in the near infrared range by varying the concentration of gold deposited on the surface of liposomes. Varying the plasmon resonant wavelengths of gold-coated liposomes can provide a method for spectrally-coding their light-mediated content release, so that the release event is initiated by the specific wavelength of light used to illuminate the liposomes. The development of spectrally-coded release can find applications in controlled delivery of multiple agents to support complex diagnostic tests and therapeutic interventions.

  20. Plasmon resonant gold-coated liposomes for spectrally coded content release.

    PubMed

    Leung, Sarah J; Troutman, Timothy S; Romanowski, Marek

    2009-02-01

    We have recently introduced liposome-supported plasmon resonant gold nanoshells (Troutman et al., Adv. Mater. 2008, 20, 2604-2608). These plasmon resonant gold-coated liposomes are degradable into components of a size compatible with renal clearance, potentially enabling their use as multifunctional agents in applications in nanomedicine, including imaging, diagnostics, therapy, and drug delivery. The present research demonstrates that laser illumination at the wavelength matching the plasmon resonance band of a gold-coated liposome leads to the rapid release of encapsulated substances, which can include therapeutic and diagnostic agents. Leakage of encapsulated contents is monitored through the release of self-quenched fluorescein, which provides an increase in fluorescence emission upon release. Moreover, the resonant peak of these gold-coated liposomes is spectrally tunable in the near infrared range by varying the concentration of gold deposited on the surface of liposomes. Varying the plasmon resonant wavelengths of gold-coated liposomes can provide a method for spectrally-coding their light-mediated content release, so that the release event is initiated by the specific wavelength of light used to illuminate the liposomes. The development of spectrally-coded release can find applications in controlled delivery of multiple agents to support complex diagnostic tests and therapeutic interventions.

  1. Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering

    SciTech Connect

    Gao, Xuan; Casa, Diego; Kim, Jungho; Gog, Thomas; Li, Chengyang; Burns, Clement

    2016-08-15

    Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Moreover we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals.

  2. Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering

    SciTech Connect

    Gao, Xuan; Casa, Diego; Kim, Jungho; Gog, Thomas; Li, Chengyang; Burns, Clement

    2016-08-15

    Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Here we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals.

  3. Coherent nuclear resonant scattering by {sup 61}Ni using the nuclear lighthouse effect

    SciTech Connect

    Roth, T.; Leupold, O.; Wille, H.-C.; Rueffer, R.; Quast, K.W.; Burkel, E.; Roehlsberger, R.

    2005-04-01

    We have observed coherent nuclear resonant scattering of synchrotron radiation from the 67.41-keV level of {sup 61}Ni. The time evolution of the forward scattering signal was recorded by employing the nuclear lighthouse effect. This method is used to investigate Moessbauer isotopes in a coherent scattering process with synchrotron radiation at high transition energies. The decay of the excited ensemble of nuclei in Ni metal shows quantum beats that allowed the determination of the magnetic hyperfine field at the {sup 61}Ni nucleus. Moreover, we determined the lifetime of the 67.41-keV level of {sup 61}Ni to be 7.4(1) ns.

  4. Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Gao, Xuan; Casa, Diego; Kim, Jungho; Gog, Thomas; Li, Chengyang; Burns, Clement

    2016-08-01

    Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Here we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals.

  5. Resonant inelastic soft x-ray scattering at double core excitations in solid LiCl

    SciTech Connect

    Agaaker, Marcus; Ahuja, Rajeev; Soederstroem, Johan; Rubensson, Jan-Erik; Kaeaembre, Tanel; Glover, Chris; Schmitt, Thorsten; Mattesini, Maurizio

    2006-06-15

    Inelastic soft x-ray scattering in LiCl, resonantly enhanced at states with two Li 1s vacancies, is investigated. States in which both excited electrons are localized during the double core hole lifetime, in which one of the electrons delocalize, as well as triply excited states in which the double core excitation is accompanied by a valence-to-conduction band excitation, contribute to the scattering. The angular momentum symmetry of the involved states and the vibronic coupling during the scattering process are reflected in the angular anisotropy. The effect on the local electronic structure of multiple core holes is theoretically studied by means of supercell band calculations.

  6. Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe1-xMxSi, M=Ir,Os

    DOE PAGES

    Delaire, O.; Al-Qasir, Iyad I.; May, Andrew F.; ...

    2015-03-31

    The vibrational behavior of heavy substitutional impurities (M=Ir,Os) in Fe1-xMxSi (x = 0, 0.02, 0.04, 0.1) was investigated with a combination of inelastic neutron scattering (INS), transport measurements, and first-principles simulations. In this paper, our INS measurements on single-crystals mapped the four-dimensional dynamical structure factor, S(Q;E), for several compositions and temperatures. Our results show that both Ir and Os impurities lead to the formation of a weakly dispersive resonance vibrational mode, in the energy range of the acoustic phonon dispersions of the FeSi host. We also show that Ir doping, which introduces free carriers and increases electron-phonon coupling, leads tomore » softened interatomic force-constants compared to doping with Os, which is isoelectronic to Fe. We analyze the phonon S(Q,E) from INS through a Green's function model incorporating the phonon self-energy based on first-principles density functional theory (DFT) simulations. Calculations of the quasiparticle spectral functions in the doped system reveal the hybridization between the resonance and the acoustic phonon modes. Finally, our results demonstrate a strong interaction of the host acoustic dispersions with the resonance mode, likely leading to the large observed suppression in lattice thermal conductivity.« less

  7. Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe1-xMxSi (M =Ir , Os )

    NASA Astrophysics Data System (ADS)

    Delaire, O.; Al-Qasir, I. I.; May, A. F.; Li, C. W.; Sales, B. C.; Niedziela, J. L.; Ma, J.; Matsuda, M.; Abernathy, D. L.; Berlijn, T.

    2015-03-01

    The vibrational behavior of heavy substitutional impurities (M = Ir,Os) in Fe1-xMxSi (x =0 ,0.02 ,0.04 ,0.1 ) was investigated with a combination of inelastic neutron scattering (INS), transport measurements, and first-principles simulations. Our INS measurements on single crystals mapped the four-dimensional dynamical structure factor, S (Q ,E ) , for several compositions and temperatures. Our results show that both Ir and Os impurities lead to the formation of a weakly dispersive resonance vibrational mode, in the energy range of the acoustic phonon dispersions of the FeSi host. We also show that Ir doping, which introduces free carriers, leads to softened interatomic force constants compared to doping with Os, which is isoelectronic to Fe. We analyze the phonon S (Q ,E ) from INS through a Green's-function model incorporating the phonon self-energy based on first-principles density functional theory simulations, and we study the disorder-induced lifetimes on large supercells. Calculations of the quasiparticle spectral functions in the doped system reveal the hybridization between the resonance and the acoustic phonon modes. Our results demonstrate a strong interaction of the host acoustic dispersions with the resonance mode, likely leading to the large observed suppression in lattice thermal conductivity.

  8. Characterizing riverbed sediment using high-frequency acoustics 1: spectral properties of scattering

    USGS Publications Warehouse

    Buscombe, Daniel D.; Grams, Paul E.; Kaplinski, Matt A.

    2014-01-01

    Bed-sediment classification using high-frequency hydro-acoustic instruments is challenging when sediments are spatially heterogeneous, which is often the case in rivers. The use of acoustic backscatter to classify sediments is an attractive alternative to analysis of topography because it is potentially sensitive to grain-scale roughness. Here, a new method is presented which uses high-frequency acoustic backscatter from multibeam sonar to classify heterogeneous riverbed sediments by type (sand, gravel,rock) continuously in space and at small spatial resolution. In this, the first of a pair of papers that examine the scattering signatures from a heterogeneous riverbed, methods are presented to construct spatially explicit maps of spectral properties from geo-referenced point clouds of geometrically and radiometrically corrected echoes. Backscatter power spectra are computed to produce scale and amplitude metrics that collectively characterize the length scales of stochastic measures of riverbed scattering, termed ‘stochastic geometries’. Backscatter aggregated over small spatial scales have spectra that obey a power-law. This apparently self-affine behavior could instead arise from morphological- and grain-scale roughnesses over multiple overlapping scales, or riverbed scattering being transitional between Rayleigh and geometric regimes. Relationships exist between stochastic geometries of backscatter and areas of rough and smooth sediments. However, no one parameter can uniquely characterize a particular substrate, nor definitively separate the relative contributions of roughness and acoustic impedance (hardness). Combinations of spectral quantities do, however, have the potential to delineate riverbed sediment patchiness, in a data-driven approach comparing backscatter with bed-sediment observations (which is the subject of part two of this manuscript).

  9. Determination of thorium (IV) using isophthalaldehyde-tetrapyrrole as probe by resonance light scattering, second-order scattering and frequency-doubling scattering spectra.

    PubMed

    Wang, Jiao; Xue, Jinhua; Xiao, Xilin; Xu, Li; Jiang, Min; Peng, Pengcheng; Liao, Lifu

    2017-12-05

    The coordination reaction of thorium (IV) with a ditopic bidentate ligand to form supramolecular polymer was studied by resonance light scattering (RLS) spectra, second-order scattering (SOS) spectra and frequency-doubling scattering (FDS) spectra, respectively. The ditopic bidentate ligand is isophthalaldehyde-tetrapyrrole (IPTP). It was synthesized through a condensation reaction of isophthalaldehyde with pyrrole. The formation of supramolecular polymer results in remarkable intensity enhancements of the three light scattering signals. The maximum scattering wavelengths of RLS, FDS and SOS were 290, 568 and 340nm, respectively. The reaction was used to establish new light scattering methods for the determination of thorium (IV) by using IPTP as probe. Under optimum conditions, the intensity enhancements of RLS, SOS and FDS were directly proportional to the concentration of thorium (IV) in the ranges of 0.01 to 1.2μgmL(-1), 0.05 to 1.2μgmL(-1) and 0.05 to 1.2μgmL(-1), respectively. The detection limits were 0.003μgmL(-1), 0.012μgmL(-1) and 0.021μgmL(-1), respectively. The methods were suitable for analyzing thorium (IV) in actual samples. The results show acceptable recoveries and precision compared with a reference method. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

  11. Acoustic resonances and sound scattering by a shear layer

    NASA Technical Reports Server (NTRS)

    Koutsoyannis, S. P.; Karamcheti, K.; Galant, D. C.

    1980-01-01

    The reflection and transmission characteristics of plane waves scattered by a finite-thickness shear layer having a linear velocity profile and bounded by two otherwise uniform parallel flows is examined using the pressure perturbation equation solutions in the shear layer shown previously to be in terms of Whittaker M functions. In addition to the angle of plane wave incidence and the relative Mach number of the flows bounding the shear layer, it is found that the scattering properties of the shear layer depend crucially upon a parameter tau in such a manner that the case tau approaching zero characterizes the long wavelength properties of the layer and the case tau approaching infinity characterizes the short wavelength properties of the layer. In contrast to the region of ordinary reflection in the cases where the corresponding vortex sheet does not have a Brewster angle, the values of the reflection coefficient up to tau of 2 follow those of the vortex sheet; for the case for which the corresponding vortex sheet has a Brewster angle, the magnitude of the reflection coefficient may be sensitive to even small changes in tau in certain cases.

  12. Accurate palm vein recognition based on wavelet scattering and spectral regression kernel discriminant analysis

    NASA Astrophysics Data System (ADS)

    Elnasir, Selma; Shamsuddin, Siti Mariyam; Farokhi, Sajad

    2015-01-01

    Palm vein recognition (PVR) is a promising new biometric that has been applied successfully as a method of access control by many organizations, which has even further potential in the field of forensics. The palm vein pattern has highly discriminative features that are difficult to forge because of its subcutaneous position in the palm. Despite considerable progress and a few practical issues, providing accurate palm vein readings has remained an unsolved issue in biometrics. We propose a robust and more accurate PVR method based on the combination of wavelet scattering (WS) with spectral regression kernel discriminant analysis (SRKDA). As the dimension of WS generated features is quite large, SRKDA is required to reduce the extracted features to enhance the discrimination. The results based on two public databases-PolyU Hyper Spectral Palmprint public database and PolyU Multi Spectral Palmprint-show the high performance of the proposed scheme in comparison with state-of-the-art methods. The proposed approach scored a 99.44% identification rate and a 99.90% verification rate [equal error rate (EER)=0.1%] for the hyperspectral database and a 99.97% identification rate and a 99.98% verification rate (EER=0.019%) for the multispectral database.

  13. Lorentzian amplitude and phase pulse shaping for nonresonant background suppression and enhanced spectral resolution in coherent anti-Stokes Raman scattering spectroscopy and microscopy.

    PubMed

    Konorov, Stanislav O; Blades, Michael W; Turner, Robin F B

    2010-07-01

    Femtosecond coherent anti-Stokes Raman scattering (CARS) spectroscopy offers several advantages over spontaneous Raman spectroscopy due to the inherently high sensitivity and low average power deposition in the sample. Femtosecond CARS can be implemented in a collinear pump/probe beam configuration for microspectroscopy applications and has emerged as a powerful technique for chemical imaging of biological specimens. However, one serious limitation of this approach is the presence of a high nonresonant background component that often obscures the resonant signals of interest. We report here an innovative pulse-shaping method based on Lorentzian amplitude and phase spectral modulation of a broadband femtosecond probe pulse that yields spectra with both high spectral resolution and no nonresonant background. No further mathematical analysis is needed to extract Raman spectra. The utility of the proposed method for CARS microscopy is demonstrated using a mixture of polystyrene and latex beads, as well as dry-fixed embryonic stem cells.

  14. Spectral wide-field microscopic fluorescence resonance energy transfer imaging in live cells.

    PubMed

    Zhang, Lili; Qin, Guiqi; Chai, Liuying; Zhang, Jiang; Yang, Fangfang; Yang, Hongqin; Xie, Shusen; Chen, Tongsheng

    2015-08-01

    With its precise, sensitive, and nondestructive features, spectral unmixing-based fluorescence resonance energy transfer (FRET) microscopy has been widely applied to visualize intracellular biological events. In this report, we set up a spectral wide-field microscopic FRET imaging system by integrating a varispec liquid crystal tunable filter into a wide-field microscope for quantitative FRET measurement in living cells. We implemented a representative emission-spectral unmixing-based FRET measurement method on this platform to simultaneously acquire pixel-to-pixel images of both FRET efficiency (E ) and acceptor-to-donor concentration ratio (R C ) in living HepG2 cells expressing fusion proteins in the presence or absence of free donors and acceptors and obtained consistent results with other instruments and methods. This stable and low-cost spectral wide-field microscopic FRET imaging system provides a new toolbox for imaging molecular events with high spatial resolution in living cells.

  15. Resonance contributions to anti-Stokes/Stokes ratios under surface enhanced Raman scattering conditions

    NASA Astrophysics Data System (ADS)

    Maher, R. C.; Hou, J.; Cohen, L. F.; Le Ru, E. C.; Hadfield, J. M.; Harvey, J. E.; Etchegoin, P. G.; Liu, F. M.; Green, M.; Brown, R. J. C.; Milton, M. J. T.

    2005-08-01

    Anti-Stokes/Stokes asymmetries under surface enhanced Raman scattering (SERS) conditions are studied for a wide variety of SERS-active media and different analytes. Evidence is provided for the existence of underlying resonances that create these asymmetries. We show here that these resonances are associated with the electromagnetic coupling between the analyte (probe) and the metal. The work demonstrates the use of the anti-Stokes/Stokes ratio as a tool to understand the hierarchy of resonances in the SERS problem, which is essential for quantification purposes.

  16. High-sensitivity pesticide detection using particle-enhanced resonant Raman scattering

    NASA Astrophysics Data System (ADS)

    Ranjan, Bikas; Saito, Yuika; Verma, Prabhat

    2016-03-01

    The use of pesticides in agriculture has raised concerns, as even a small residual of pesticide on food can be harmful. It is therefore of great importance to develop a robust technique to detect tiny amounts of pesticides. Although Raman spectroscopy is frequently used for chemical identification, it is not suitable for extremely low molecular concentrations. We propose a technique called particle-enhanced resonant Raman spectroscopy to detect extremely low concentrations of pesticides, where gold nanoparticles of desired plasmonic resonance are synthesized to match the resonance in Raman scattering. We successfully demonstrated the detection of extremely low amounts of pesticides on oranges.

  17. Directly Characterizing the Relative Strength and Momentum Dependence of Electron-Phonon Coupling Using Resonant Inelastic X-Ray Scattering

    DOE PAGES

    Devereaux, T. P.; Shvaika, A. M.; Wu, K.; ...

    2016-10-25

    The coupling between lattice and charge degrees of freedom in condensed matter materials is ubiquitous and can often result in interesting properties and ordered phases, including conventional superconductivity, charge-density wave order, and metal-insulator transitions. Angle-resolved photoemission spectroscopy and both neutron and nonresonant x-ray scattering serve as effective probes for determining the behavior of appropriate, individual degrees of freedom—the electronic structure and lattice excitation, or phonon dispersion, respectively. However, each provides less direct information about the mutual coupling between the degrees of freedom, usually through self-energy effects, which tend to renormalize and broaden spectral features precisely where the coupling is strong,more » impacting one’s ability to quantitatively characterize the coupling. Here, we demonstrate that resonant inelastic x-ray scattering, or RIXS, can be an effective tool to directly determine the relative strength and momentum dependence of the electron-phonon coupling in condensed matter systems. Using a diagrammatic approach for an eight-band model of copper oxides, we study the contributions from the lowest-order diagrams to the full RIXS intensity for a realistic scattering geometry, accounting for matrix element effects in the scattering cross section, as well as the momentum dependence of the electron-phonon coupling vertex. A detailed examination of these maps offers a unique perspective into the characteristics of electron-phonon coupling, which complements both neutron and nonresonant x-ray scattering, as well as Raman and infrared conductivity.« less

  18. Measurements of the {sup 6}He+p resonant scattering

    SciTech Connect

    Condori, R. Pampa; Lichtenthäler, R.; Lépine-Szily, A.; Gasques, L. R.; Morais, M. C.; Scarduelli, V. B.; Leistenschneider, E.; Alcántara-Núñez, J. A.; Faria, P. N. de; Mendes Jr, D. R.; Pires, K. C. C.; Shorto, J. M. B.

    2014-11-11

    Measurements of the p({sup 6}He,p) elastic scattering excitation function have been performed in the RIBRAS system using a {sup 6}He secondary beam and a CH{sub 2} polyethylene thick target. The motivation is to observe states of the compound nucleus {sup 7}Li in the excitation energy range of E{sub exc}{sup 7Li} = 10.8-11.8MeV, where the isobaric analog state of {sup 7}He ground state lies. Excitation functions have been obtained at three laboratory angles θ{sub lab} = 0°, 20°, and 25° which correspond to θ{sub c.m} = 180°, 140°, and 130°.

  19. Vibrational relaxation of nascent diiodide ions studied by femtosecond transient resonance impulsive stimulated Raman scattering (TRISRS); experiment and simulation

    NASA Astrophysics Data System (ADS)

    Banin, Uri; Kosloff, Ronnie; Ruhman, Sanford

    1994-06-01

    Impulsive stimulated Raman scattering performed with femtosecond pulses on resonance with an electronic transition, comprises an all time domain Raman technique providing vibrational dynamics of the ground state chromophore. We report the application of this technique to record transient Raman responses of nascent diiodide ions, undergoing rapid vibrational relaxation following triiodide photodissociation in ethanol solution. Like other Fourier spectroscopic methods, this spectroscopy maximizes high simultaneous time and frequency resolution, making it well adapted, and in the present study exclusively capable, for recovering vibrational dynamics of highly excited molecular populations in transition. Master equation simulations of vibrational relaxation, coupled to quantum wave-packet representation of the light-matter interactions, are combined to provide a semi-quantitative analysis of the experimental results. Previous assignment of spectral narrowing of the nascent diiodide absorption to vibrational relaxation is bourn out by simulations. Inherent limitations and fortitudes of the TRISRS method are theoretically investigated and discussed.

  20. Fingerprints of the anisotropic spin-split hole dispersion in resonant inelastic light scattering in two-dimensional hole systems.

    PubMed

    Hirmer, M; Hirmer, M; Schuh, D; Wegscheider, W; Korn, T; Winkler, R; Schüller, C

    2011-11-18

    In resonant inelastic light scattering experiments on two-dimensional hole systems in GaAs-Al(x)Ga(1-x)As single quantum wells we find evidence for the strongly anisotropic spin-split hole dispersion at finite in-plane momenta. In all our samples we detect a low-energy spin-density excitation of a few meV, stemming from excitation of holes of the spin-split ground state. The detailed spectral shape of the excitation depends sensitively on the orientations of the linear light polarizations with respect to the in-plane crystal axes. In particular, we observe a doublet structure, which is most pronounced if the polarization of the incident light is parallel to the [110] in-plane direction. Theoretical calculations of the Raman spectra based on a multiband k · p approach confirm that the observed doublet structure is due to the anisotropic spin-split hole dispersion.

  1. Resonant Scattering off Magnetic Impurities in Graphene: Mechanism for Ultrafast Spin Relaxation

    NASA Astrophysics Data System (ADS)

    Kochan, D.; Gmitra, M.; Fabian, J.

    We give a tutorial account of our recently proposed mechanism for spin relaxation based on spin-flip resonant scattering off local magnetic moments. The mechanism is rather general, working in any material with a resonant local moment, but we believe that its particular niche is graphene, whose measured spin relaxation time is 100-1000 ps. Conventional spin-orbit coupling based mechanisms (Elliott-Yafet or Dyakonov-Perel) would require large concentrations (1000 ppm) of impurities to explain this. Our mechanism needs only 1 ppm of resonant local moments, as these act as local spin hot spots: the resonant scatterers do not appear to substantially affect graphene's measured resistivity, but are dominating spin relaxation. In principle, the local moments can come from a variety of sources. Most likely would be organic molecule adsorbants or metallic adatoms. As the representative model, particularly suited for a tutorial, we consider hydrogen adatoms which are theoretically and experimentally demonstrated to yield local magnetic moments when chemisorbed on graphene. We introduce the scattering formalism and apply it to graphene, to obtain the T-matrix and spin-flip scattering rates using the generalized Fermi golden rule.

  2. Resonant X-Ray Scattering Studies of Charge Order in Cuprates

    NASA Astrophysics Data System (ADS)

    Comin, Riccardo; Damascelli, Andrea

    2016-03-01

    X-ray techniques have been used for more than a century to study the atomic and electronic structure in practically any type of material. The advent of correlated electron systems, in particular complex oxides, brought about new scientific challenges and opportunities for the advancement of conventional X-ray methods. In this context, the need for new approaches capable of selectively sensing new forms of orders involving all degrees of freedom -- charge, orbital, spin, and lattice -- paved the way for the emergence and success of resonant X-ray scattering, which has become an increasingly popular and powerful tool for the study of electronic ordering phenomena in solids. We review the recent resonant X-ray scattering breakthroughs in the copper oxide high-temperature superconductors, in particular regarding the phenomenon of charge order, a broken-symmetry state occurring when valence electrons self-organize into periodic structures. After a brief historical perspective on charge order, we outline the milestones in the development of resonant X-ray scattering as well as the basic theoretical formalism underlying its unique capabilities. The rest of the review focuses on the recent contributions of resonant scattering to the advancements in our description and understanding of charge order. To conclude, we propose a series of present and upcoming challenges and discuss the future outlook for this technique.

  3. Positron and electron scattering by glycine and alanine: Shape resonances and methylation effect

    NASA Astrophysics Data System (ADS)

    Nunes, Fernanda B.; Bettega, Márcio H. F.; Sanchez, Sergio d'Almeida

    2016-12-01

    We report integral cross sections (ICSs) for both positron and electron scattering by glycine and alanine amino acids. These molecules differ only by a methyl group. We computed the scattering cross sections using the Schwinger multichannel method for both glycine and alanine in different levels of approximation for both projectiles. The alanine ICSs are greater in magnitude than the glycine ICSs for both positron and electron scattering, probably due to the larger size of the molecule. In electron scattering calculations, we found two resonances for each molecule. Glycine presents one at 1.8 eV, and another centered at around 8.5 eV, in the static-exchange plus polarization (SEP) approximation. The ICS for alanine shows one resonance at 2.5 eV and another at around 9.5 eV, also in SEP approximation. The results are in good agreement with most of the data present in the literature. The comparison of the electron scattering ICSs for both molecules indicates that the methylation of glycine destabilizes the resonances, shifting them to higher energies.

  4. An exploration in acoustic radiation force experienced by cylindrical shells via resonance scattering theory.

    PubMed

    Rajabi, Majid; Behzad, Mehdi

    2014-04-01

    In nonlinear acoustic regime, a body insonified by a sound field is known to experience a steady force that is called the acoustic radiation force (RF). This force is a second-order quantity of the velocity potential function of the ambient medium. Exploiting the sufficiency of linear solution representation of potential function in RF formulation, and following the classical resonance scattering theorem (RST) which suggests the scattered field as a superposition of the resonant field and a background (non-resonant) component, we will show that the radiation force is a composition of three components: background part, resonant part and their interaction. Due to the nonlinearity effects, each part contains the contribution of pure partial waves in addition to their mutual interaction. The numerical results propose the residue component (i.e., subtraction of the background component from the RF) as a good indicator of the contribution of circumferential surface waves in RF. Defining the modal series of radiation force function and its components, it will be shown that within each partial wave, the resonance contribution can be synthesized as the Breit-Wigner form for adequately none-close resonant frequencies. The proposed formulation may be helpful essentially due to its inherent value as a canonical subject in physical acoustics. Furthermore, it may make a tunnel through the circumferential resonance reducing effects on radiation forces. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Visual sandwich immunoassay system on the basis of plasmon resonance scattering signals of silver nanoparticles.

    PubMed

    Ling, Jian; Li, Yuan Fang; Huang, Cheng Zhi

    2009-02-15

    In this contribution, we established a sandwich immunoassay system with a common spectrofluorometer to collect the plasmon resonance scattering (PRS) signals from silver nanoparticles (AgNPs) immunotargeted on glass slides. By taking the immunoreactions of goat antihuman IgG (Fc fragment specific) antibody (GAH-IgG), human immunoglobulin (H-IgG), and rabbit antihuman IgG (Fab fragment specific) antibody (RAH-IgG) as an example, we found that if a primary antibody (GAH-IgG) was first immobilized on the surface of glass slides and applied to capture target antigen (H-IgG), AgNPs-labeled secondary antibody (RAH-IgG) could be employed to detect the target antigen (H-IgG) by forming a sandwich immune complex on the surface of the glass slide. It was found that the PRS signals resulting from the AgNPs immunotargeted on the glass slides could be applied to the quantitative detection of H-IgG target antigen in the range of 10-1000 ng/mL with the limit of determination of 1.46 ng/mL (3sigma) under optimal conditions, which is sensitive and comparable with reported chemiluminescence immunoassays. With a dark-field microscope coupled with a spectral system, we measured the PRS features of single AgNPs immunotargeted on the glass slides, showing that the PRS of single nanoparticles might have potential applications in analytical chemistry. Further findings showed that the strong PRS signals from the AgNPs immunotargeted on the glass slides can be clearly seen and distinguished by naked eyes under the excitation of a common white light-emitting diode (LED) torch. Therefore, a visual PRS immunoassay system can be established easily with common glass slides and an LED torch.

  6. Electronic Structure of Doped Lanthanum Cuprates Studied with Resonant Inelastic X-Ray Scattering

    SciTech Connect

    Hill, J.P.; Ellis, D.S.; Kim, J.; Zhang, H.; Gu, G.; Komiya, S.; Ando, Y.; Casa, D.; Gog, T.; Kim, Y.-J.

    2011-02-24

    We report a comprehensive Cu K-edge resonant inelastic x-ray scattering (RIXS) investigation of La{sub 2-x}Sr{sub x}CuO{sub 4} (LSCO) for 0 {le} x {le} 0.35, stripe-ordered La{sub 1.875}Ba{sub 0.125}CuO{sub 4} (LBCO), and La{sub 2}Cu{sub 0.96}Ni{sub 0.04}O{sub 4} (LCNO) crystals. The RIXS spectra measured at three high-symmetry momentum-transfer (q) positions are compared as a function of doping and for the different dopants. The spectra in the energy range 1-6 eV can be described with three broad peaks, which evolve systematically with increased doping. The most systematic trend was observed for q = ({pi},0) corresponding to the zone boundary. As hole doping increased, the spectral weight transfer from high energies to low energies is nearly linear with x at this q. We interpret the peaks as interband transitions in the context of existing band models for this system, assigning them to Zhang-Rice band {yields} upper Hubbard band, lower-lying band {yields} upper Hubbard band, and lower-lying band {yields} Zhang-Rice band transitions. The spectrum of stripe-ordered LBCO was also measured, and found to be identical to the correspondingly doped LSCO, except for a relative enhancement of the near-infrared peak intensity at {approx}1.5-1.7 eV. The temperature dependence of this near-infrared peak in LBCO was more pronounced than for other parts of the spectrum, continuously decreasing in intensity as the temperature was raised from 25 to 300 K. Finally, we find that 4% Ni substitution in the Cu site has a similar effect on the spectra as does Sr substitution in the La site.

  7. Variations in the cyclotron resonant scattering features during 2011 outburst of 4U 0115+63

    NASA Astrophysics Data System (ADS)

    Iyer, N.; Mukherjee, D.; Dewangan, G. C.; Bhattacharya, D.; Seetha, S.

    2015-11-01

    We study the variations in the Cyclotron Resonant Scattering Feature (CRSF) during 2011 outburst of the high mass X-ray binary 4U 0115+63 using observations performed with Suzaku, RXTE, Swift and INTEGRAL satellites. The wide-band spectral data with low-energy coverage allowed us to characterize the broad-band continuum and detect the CRSFs. We find that the broad-band continuum is adequately described by a combination of a low temperature (kT ˜ 0.8 keV) blackbody and a power law with high energy cutoff (Ecut ˜ 5.4 keV) without the need for a broad Gaussian at ˜10 keV as used in some earlier studies. Though winds from the companion can affect the emission from the neutron star at low energies (<3 keV), the blackbody component shows a significant presence in our continuum model. We report evidence for the possible presence of two independent sets of CRSFs with fundamentals at ˜11 and ˜15 keV. These two sets of CRSFs could arise from spatially distinct emitting regions. We also find evidence for variations in the line equivalent widths, with the 11 keV CRSF weakening and the 15 keV line strengthening with decreasing luminosity. Finally, we propose that the reason for the earlier observed anticorrelation of line energy with luminosity could be due to modelling of these two independent line sets (˜11 and ˜15 keV) as a single CRSF.

  8. Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.

    SciTech Connect

    Kearney, Sean Patrick

    2014-07-01

    A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited, or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparation bandwidth. Shifts of 100 cm-1 or more are attainable and allow for enhanced detection of high-energy (150-300 cm-1) rotational Raman transitions at near transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2/air flat flame.

  9. Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.

    DOE PAGES

    Kearney, Sean Patrick

    2014-07-01

    A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited, or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparationmore » bandwidth. Shifts of 100 cm-1 or more are attainable and allow for enhanced detection of high-energy (150-300 cm-1) rotational Raman transitions at near transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2/air flat flame.« less

  10. Bandwidth optimization of femtosecond pure-rotational coherent anti-Stokes Raman scattering by pump/Stokes spectral focusing.

    PubMed

    Kearney, Sean P

    2014-10-01

    A simple spectral focusing scheme for bandwidth optimization of gas-phase rotational coherent anti-Stokes Raman scattering (CARS) spectra is presented. The method is useful when femtosecond pump/Stokes preparation of the Raman coherence is utilized. The approach is of practical utility when working with laser pulses that are not strictly transform limited or when windows or other sources of pulse chirp may be present in the experiment. A delay between the femtosecond preparation pulses is introduced to shift the maximum Raman preparation away from zero frequency and toward the Stokes or anti-Stokes side of the spectrum with no loss in total preparation bandwidth. Shifts of 100 cm(-1) or more are attainable and allow for enhanced detection of high-energy (150-300 cm(-1)) rotational Raman transitions at near-transform-limited optimum sensitivity. A simple theoretical treatment for the case of identical pump and Stokes pulses with linear frequency chirp is presented. The approach is then demonstrated experimentally for typical levels of transform-limited laser performance obtained in our laboratory with nonresonant CARS in argon and Raman-resonant spectra from a lean H2 air flat flame.

  11. Partially coherent scattering in stellar chromospheres. I - Effects on resonance line thermalization

    NASA Technical Reports Server (NTRS)

    Gayley, Kenneth G.

    1992-01-01

    The conditions necessary for partially coherent scattering to influence the thermalization depth are investigated, and the effects of partial redistribution in homogeneous slab atmospheres are approximated using several common resonance lines as examples. For electron densities above 10 exp 10/cu cm, it is concluded that even when coherent scattering dominates the escape process, the thermalization depths of the strongest resonance lines of H, Ca II, and Mg II agree roughly with the Doppler diffusion in frequency. No elastic scattering effects on the thermalization of Mg II h and k and Ca II H and K are found. At lower densities, such as for giant star chromospheres and QSO models, the results deviate strongly from the Doppler complete redistribution case.

  12. Nonadiabaticity in a Jahn-Teller system probed by absorption and resonance Raman scattering.

    PubMed

    Pae, K; Hizhnyakov, V

    2013-03-14

    A theory of absorption and resonance Raman scattering of impurity centers in crystals with E⊗e-type Jahn-Teller effect in the excited state is presented. The vibronic interaction with non-totally symmetric local or pseudolocal modes and with a continuum of bath modes (phonons) is considered. A number of specific quantum effects, such as the nonadiabaticity-induced enhancement of the Raman scattering at high-energy excitation, the size effect of the final state, the interference of different channels of scattering, the Fermi resonances in the conical intersection, and others, were shown to become apparent in the calculated spectra. The vibronic interaction with phonons essentially determines the structure of the spectra.

  13. Direct detection of resonant electron pitch angle scattering by whistler waves in a laboratory plasma.

    PubMed

    Van Compernolle, B; Bortnik, J; Pribyl, P; Gekelman, W; Nakamoto, M; Tao, X; Thorne, R M

    2014-04-11

    Resonant interactions between energetic electrons and whistler mode waves are an essential ingredient in the space environment, and in particular in controlling the dynamic variability of Earth's natural radiation belts, which is a topic of extreme interest at the moment. Although the theory describing resonant wave-particle interaction has been present for several decades, it has not been hitherto tested in a controlled laboratory setting. In the present Letter we report on the first laboratory experiment to directly detect resonant pitch angle scattering of energetic (∼keV) electrons due to whistler mode waves. We show that the whistler mode wave deflects energetic electrons at precisely the predicted resonant energy, and that varying both the maximum beam energy, and the wave frequency, alters the energetic electron beam very close to the resonant energy.

  14. Triple-Resonant Brillouin Light Scattering in Magneto-Optical Cavities

    NASA Astrophysics Data System (ADS)

    Haigh, J. A.; Nunnenkamp, A.; Ramsay, A. J.; Ferguson, A. J.

    2016-09-01

    An enhancement in Brillouin light scattering of optical photons with magnons is demonstrated in magneto-optical whispering gallery mode resonators tuned to a triple-resonance point. This occurs when both the input and output optical modes are resonant with those of the whispering gallery resonator, with a separation given by the ferromagnetic resonance frequency. The identification and excitation of specific optical modes allows us to gain a clear understanding of the mode-matching conditions. A selection rule due to wave vector matching leads to an intrinsic single-sideband excitation. Strong suppression of one sideband is essential for one-to-one frequency mapping in coherent optical-to-microwave conversion.

  15. Scattering amplitude of ultracold atoms near the p-wave magnetic Feshbach resonance

    SciTech Connect

    Zhang Peng; Naidon, Pascal; Ueda, Masahito

    2010-12-15

    Most of the current theories on the p-wave superfluid in cold atomic gases are based on the effective-range theory for the two-body scattering, where the low-energy p-wave scattering amplitude f{sub 1}(k) is given by f{sub 1}(k)=-1/[ik+1/(Vk{sup 2})+1/R]. Here k is the incident momentum, V and R are the k-independent scattering volume and effective range, respectively. However, due to the long-range nature of the van der Waals interaction between two colliding ultracold atoms, the p-wave scattering amplitude of the two atoms is not described by the effective-range theory [J. Math. Phys. 4, 54 (1963); Phys. Rev. A 58, 4222 (1998)]. In this paper we provide an explicit calculation for the p-wave scattering of two ultracold atoms near the p-wave magnetic Feshbach resonance. We show that in this case the low-energy p-wave scattering amplitude f{sub 1}(k)=-1/[ik+1/(V{sup eff}k{sup 2})+1/(S{sup eff}k)+1/R{sup eff}] where V{sup eff}, S{sup eff}, and R{sup eff} are k-dependent parameters. Based on this result, we identify sufficient conditions for the effective-range theory to be a good approximation of the exact scattering amplitude. Using these conditions we show that the effective-range theory is a good approximation for the p-wave scattering in the ultracold gases of {sup 6}Li and {sup 40}K when the scattering volume is enhanced by the resonance.

  16. Acoustic resonances and sound scattering by a shear layer

    NASA Technical Reports Server (NTRS)

    Koutsoyannis, S. P.; Karamcheti, K.; Galant, D. C.

    1979-01-01

    The energy reflection coefficient is evaluated numerically for plane waves incident on a plane shear layer having a linear velocity profile. The shear layer is found to exhibit no resonances and no Brewster angles. The behavior of the reflection coefficient depends crucially on the parameter tau, a nondimensional measure of the disturbance Strouhal number with respect to the disturbance Mach number in the mean flow direction. For moderate values of tau, the amplified reflection regime degenerates into the total reflection one, whereas in the ordinary reflection regime the variation of the reflection coefficient with tau depends on whether or not the corresponding vortex sheet has a Brewster angle. The results indicate that caution should be exercised in uncritically modeling a finite thickness shear layer by a corresponding vortex sheet.

  17. Advanced coupled-micro-resonator architectures for dispersion and spectral engineering applications

    NASA Astrophysics Data System (ADS)

    Van, Vien

    2009-02-01

    We report recent progress in the design and fabrication of coupled optical micro-resonators and their applications in realizing compact OEIC devices for optical spectral engineering. By leveraging synthesis techniques for analog and digital electrical circuits, advanced coupled-microring device architectures can be realized with the complexity and functionality approaching that of state-of-the-art microwave filters. In addition, the traveling wave nature of microring resonators can be exploited to realize novel devices not possible with standing wave resonators. Applications of coupledmicro- resonator devices in realizing complex optical transfer functions for amplitude, phase and group delay engineering will be presented. Progress in the practical implementation of these devices in the Silicon-on-Insulator OEIC platform will be highlighted along with the challenges and potential for constructing very high order optical filters using coupledmicroring architectures.

  18. Spectral response of localized surface plasmon in resonance with mid-infrared light

    SciTech Connect

    Kusa, Fumiya; Ashihara, Satoshi

    2014-10-21

    We study spectral responses of localized surface plasmons (LSPs) in gold nanorods, which resonate at mid-infrared frequencies, by transmission spectroscopy and electromagnetic field analyses. The resonance linewidth is found to be linearly proportional to the resonance frequency, indicating that the dephasing due to Drude relaxation is suppressed and that the overall dephasing is dominated by radiative damping. Owing to the reduced radiative/non-radiative damping and large geometrical length of the nanorod, near-field intensity enhancement exceeds several hundred times. Nonetheless the resonance linewidth is comparable with or larger than the bandwidth of a 100-fs pulse, and therefore the enhanced near-field as short as 100-fs can be created upon pulsed excitation. The large enhancements with appropriate bandwidths make LSPs promising for enhanced nonlinear spectroscopies, coherent controls, and strong-field light-matter interactions in the mid-infrared range.

  19. Spectral and angular characteristics of dielectric resonator metasurface at optical frequencies

    SciTech Connect

    Zou, Longfang; López-García, Martin; Oulton, Ruth; Klemm, Maciej; Withayachumnankul, Withawat; Fumeaux, Christophe; Shah, Charan M.; Mitchell, Arnan; Bhaskaran, Madhu; Sriram, Sharath

    2014-11-10

    The capability of manipulating light at subwavelength scale has fostered the applications of flat metasurfaces in various fields. Compared to metallic structure, metasurfaces made of high permittivity low-loss dielectric resonators hold the promise of high efficiency by avoiding high conductive losses of metals at optical frequencies. This letter investigates the spectral and angular characteristics of a dielectric resonator metasurface composed of periodic sub-arrays of resonators with a linearly varying phase response. The far-field response of the metasurface can be decomposed into the response of a single grating element (sub-array) and the grating arrangement response. The analysis also reveals that coupling between resonators has a non-negligible impact on the angular response. Over a wide wavelength range, the simulated and measured angular characteristics of the metasurface provide a definite illustration of how different grating diffraction orders can be selectively suppressed or enhanced through antenna sub-array design.

  20. Spectral Light Absorption and Scattering by Aerosol Particles in Central Amazonia

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Holanda, B. A.; Ferreira De Brito, J.; Carbone, S.; Barbosa, H. M.; Rizzo, L. V.; Cirino, G. G.; Andreae, M. O.; Saturno, J.; Pöhlker, C.; Martin, S. T.; Holben, B. N.; Schafer, J.

    2015-12-01

    As part of the GoAmazon2014/5, a detailed characterization of spectral light absorption and light scattering was performed at four research sites located in the central Amazon forest at different distances upwind and downwind of Manaus. The sites ATTO (T0a) and Embrapa (T0e) are located upwind of Manaus where it is possible to observe very pristine atmospheric conditions in wet season. The site Tiwa (T2) is being operated under the direct influence of the Manaus plume at 5 km downwind of Manaus and, finally, the Manacapuru (T3) site is located at about 60 km downwind of Manaus. The spectral dependence of light absorption and light scattering were measured using Aethalometers (7-wavelengths) and Nephelometers (3-wavelengths), respectively. By calculating the Absorption Angstrom Exponent (AAE), it was possible to get information about the source of the aerosol whereas the Scattering Angstrom Exponent (SAE) gives information about its size distribution. Sunphotometers from the AERONET network were set up at T3 and T0e sites to measure column Aerosol Optical Depth (AOD). For all the stations, much higher absorption and scattering coefficients were observed during the dry season in comparison to the wet season, as a result of the larger concentration of BC and OC present in the biomass burning events. Additionally, we also observed Manaus plume pollution that alters the BC signal. There is also an increase of the AAE during the dry season due to the larger amount of aerosols from biomass burning compared with urban pollution. High values of AAE are also observed during the wet season, attributed to the presence of long-range transport of aerosols from Africa. The SAE for all the sites are lower during the wet season, with the dominance of large biological particles, and increases during the dry season as a consequence of fine particles emitted from both biomass and fossil fuel burning. The AOD at T0e and T3 (Jan-Jun/2014) showed very similar values ranging from 0.05 to

  1. Multiple scattering dynamics of fermions at an isolated p-wave resonance

    NASA Astrophysics Data System (ADS)

    Thomas, R.; Roberts, K. O.; Tiesinga, E.; Wade, A. C. J.; Blakie, P. B.; Deb, A. B.; Kjærgaard, N.

    2016-07-01

    The wavefunction for indistinguishable fermions is anti-symmetric under particle exchange, which directly leads to the Pauli exclusion principle, and hence underlies the structure of atoms and the properties of almost all materials. In the dynamics of collisions between two indistinguishable fermions, this requirement strictly prohibits scattering into 90° angles. Here we experimentally investigate the collisions of ultracold clouds fermionic 40K atoms by directly measuring scattering distributions. With increasing collision energy we identify the Wigner threshold for p-wave scattering with its tell-tale dumb-bell shape and no 90° yield. Above this threshold, effects of multiple scattering become manifest as deviations from the underlying binary p-wave shape, adding particles either isotropically or axially. A shape resonance for 40K facilitates the separate observation of these two processes. The isotropically enhanced multiple scattering mode is a generic p-wave threshold phenomenon, whereas the axially enhanced mode should occur in any colliding particle system with an elastic scattering resonance.

  2. Multiple scattering dynamics of fermions at an isolated p-wave resonance

    PubMed Central

    Thomas, R.; Roberts, K. O.; Tiesinga, E.; Wade, A. C. J.; Blakie, P. B.; Deb, A. B.; Kjærgaard, N.

    2016-01-01

    The wavefunction for indistinguishable fermions is anti-symmetric under particle exchange, which directly leads to the Pauli exclusion principle, and hence underlies the structure of atoms and the properties of almost all materials. In the dynamics of collisions between two indistinguishable fermions, this requirement strictly prohibits scattering into 90° angles. Here we experimentally investigate the collisions of ultracold clouds fermionic 40K atoms by directly measuring scattering distributions. With increasing collision energy we identify the Wigner threshold for p-wave scattering with its tell-tale dumb-bell shape and no 90° yield. Above this threshold, effects of multiple scattering become manifest as deviations from the underlying binary p-wave shape, adding particles either isotropically or axially. A shape resonance for 40K facilitates the separate observation of these two processes. The isotropically enhanced multiple scattering mode is a generic p-wave threshold phenomenon, whereas the axially enhanced mode should occur in any colliding particle system with an elastic scattering resonance. PMID:27396294

  3. Raman scattering enhancement in photon-plasmon resonance mediated metal-dielectric microcavity

    SciTech Connect

    Guddala, Sriram; Narayana Rao, D. E-mail: dnrsp@uohyd.ernet.in; Dwivedi, Vindesh K.; Vijaya Prakash, G.

    2013-12-14

    Here, we report the photon-plasmon interaction scheme and enhanced field strengths resulted into the amplification of phonon in a novel microcavity. A metal-dielectric microcavity, with unified cavity photonic mode and localized surface plasmon resonances, is visualized by impregnating the gold nanoparticles into the deep see-through nano-sized pores of porous silicon microcavity. The intense optical field strengths resulting from the photon-plasmon interactions are probed by both resonant and non-resonant Raman scattering experiments. Due to photon-plasmon-phonon interaction mechanism, several orders of enhancement in the intensity of scattered Raman Stokes photon (at 500 cm{sup −1}) are observed. Our metal nanoparticle-microcavity hybrid system shows the potential to improve the sensing figure of merit as well as the applications of plasmonics for optoelectronics, photovoltaics, and related technologies.

  4. Scattering of two coherent photons inside a one-dimensional coupled-resonator waveguide

    SciTech Connect

    Alexanian, Moorad

    2010-01-15

    We consider the coherent propagation of n photons in a one-dimensional coupled-resonator waveguide for n=2,3,4.... The scattering by a three-level atom, which resides in one of the resonators of the waveguide and gives rise to only two-photon transitions, results in a perfect quantum switch that allows either total reflection or total transmission. This is to be contrasted to the case of a single photon inside a one-dimensional resonant waveguide scattered by a two-level system with single-photon transitions where only total reflection can be accomplished; viz. the system behaves only as a perfect mirror but not as an ideal, transparent medium.

  5. Above-threshold scattering about a Feshbach resonance for ultracold atoms in an optical collider.

    PubMed

    Horvath, Milena S J; Thomas, Ryan; Tiesinga, Eite; Deb, Amita B; Kjærgaard, Niels

    2017-09-06

    Ultracold atomic gases have realized numerous paradigms of condensed matter physics, where control over interactions has crucially been afforded by tunable Feshbach resonances. So far, the characterization of these Feshbach resonances has almost exclusively relied on experiments in the threshold regime near zero energy. Here, we use a laser-based collider to probe a narrow magnetic Feshbach resonance of rubidium above threshold. By measuring the overall atomic loss from colliding clouds as a function of magnetic field, we track the energy-dependent resonance position. At higher energy, our collider scheme broadens the loss feature, making the identification of the narrow resonance challenging. However, we observe that the collisions give rise to shifts in the center-of-mass positions of outgoing clouds. The shifts cross zero at the resonance and this allows us to accurately determine its location well above threshold. Our inferred resonance positions are in excellent agreement with theory.Studies on energy-dependent scattering of ultracold atoms were previously carried out near zero collision energies. Here, the authors observe a magnetic Feshbach resonance in ultracold Rb collisions for above-threshold energies and their method can also be used to detect higher partial wave resonances.

  6. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D.

    2016-01-01

    We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180∘ at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X˜ 2A2, A˜ 2B1, and B˜ 2B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B˜ 2B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.

  7. Temporal coupled-mode theory for light scattering by an arbitrarily shaped object supporting a single resonance

    NASA Astrophysics Data System (ADS)

    Ruan, Zhichao; Fan, Shanhui

    2012-04-01

    We develop a temporal coupled-mode theory to describe the interaction of plane wave with an individual scatterer having an arbitrary shape. The theory involves the expansion of the fields on cylindrical or spherical wave basis for the two-dimensional and three-dimensional cases, respectively, and describes the scattering process in terms of a background scattering matrix and the resonant radiation coefficients into different cylindrical or spherical wave channels. This theory provides a general formula for the scattering and absorption cross sections. We show that for a subwavelength asymmetric scatterer with a single resonance, the scattering and absorption cross sections can exceed the single-resonance limit for some specific incident angles of illumination, but the sum of these cross sections over all angles has an upper limit. We validate the theory with numerical simulations of a metallic scatterer that does not have any rotation symmetry.

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

    SciTech Connect

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

    2006-06-15

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

  9. Spectral data of specular reflectance, narrow-angle transmittance and angle-resolved surface scattering of materials for solar concentrators.

    PubMed

    Good, Philipp; Cooper, Thomas; Querci, Marco; Wiik, Nicolay; Ambrosetti, Gianluca; Steinfeld, Aldo

    2016-03-01

    The spectral specular reflectance of conventional and novel reflective materials for solar concentrators is measured with an acceptance angle of 17.5 mrad over the wavelength range 300-2500 nm at incidence angles 15-60° using a spectroscopic goniometry system. The same experimental setup is used to determine the spectral narrow-angle transmittance of semi-transparent materials for solar collector covers at incidence angles 0-60°. In addition, the angle-resolved surface scattering of reflective materials is recorded by an area-scan CCD detector over the spectral range 350-1050 nm. A comprehensive summary, discussion, and interpretation of the results are included in the associated research article "Spectral reflectance, transmittance, and angular scattering of materials for solar concentrators" in Solar Energy Materials and Solar Cells.

  10. Spectral data of specular reflectance, narrow-angle transmittance and angle-resolved surface scattering of materials for solar concentrators

    PubMed Central

    Good, Philipp; Cooper, Thomas; Querci, Marco; Wiik, Nicolay; Ambrosetti, Gianluca; Steinfeld, Aldo

    2015-01-01

    The spectral specular reflectance of conventional and novel reflective materials for solar concentrators is measured with an acceptance angle of 17.5 mrad over the wavelength range 300−2500 nm at incidence angles 15–60° using a spectroscopic goniometry system. The same experimental setup is used to determine the spectral narrow-angle transmittance of semi-transparent materials for solar collector covers at incidence angles 0–60°. In addition, the angle-resolved surface scattering of reflective materials is recorded by an area-scan CCD detector over the spectral range 350–1050 nm. A comprehensive summary, discussion, and interpretation of the results are included in the associated research article “Spectral reflectance, transmittance, and angular scattering of materials for solar concentrators” in Solar Energy Materials and Solar Cells. PMID:26862556

  11. Hydrogen lines in the infrared region and spectral background for the thomson scattering diagnostics of the iter divertor plasma

    NASA Astrophysics Data System (ADS)

    Lisitsa, V. S.; Mukhin, E. E.; Kadomtsev, M. B.; Kukushkin, A. B.; Kukushkin, A. S.; Kurskiev, G. S.; Levashova, M. G.; Tolstyakov, S. Yu.

    2012-02-01

    Calculations are made of the plasma spectral background, which is important for the Thomson scattering diagnostics in the ITER divertor. Theoretical grounds have been elaborated for computing the hydrogen spectral line shapes in the infrared spectral region for a divertor plasma in ITER. The shape of the P-7 Paschen line (transition n = 7 → n = 3) located near the laser scattering signal has been calculated for various lines of sight in the ITER divertor. Contributions from different mechanisms of broadening the P-7 line have been examined. The spectral intensities of bremsstrahlung and photorecombination continuum have been calculated. All calculations use data on the spatial distribution of temperatures and densities of all species of plasma particles computed with the SOLPS4.3 code for basic operation regimes of the ITER divertor.

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

    PubMed

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

    2013-12-02

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

  13. An efficient and stable spectral method for electromagnetic scattering from a layered periodic structure

    NASA Astrophysics Data System (ADS)

    He, Ying; Nicholls, David P.; Shen, Jie

    2012-04-01

    The scattering of acoustic and electromagnetic waves by periodic structures plays an important role in a wide range of problems of scientific and technological interest. This contribution focuses upon the stable and high-order numerical simulation of the interaction of time-harmonic electromagnetic waves incident upon a periodic doubly layered dielectric media with sharp, irregular interface. We describe a boundary perturbation method for this problem which avoids not only the need for specialized quadrature rules but also the dense linear systems characteristic of boundary integral/element methods. Additionally, it is a provably stable algorithm as opposed to other boundary perturbation approaches such as Bruno and Reitich's "method of field expansions" or Milder's "method of operator expansions". Our spectrally accurate approach is a natural extension of the "method of transformed field expansions" originally described by Nicholls and Reitich (and later refined to other geometries by the authors) in the single-layer case.

  14. Line shape of amplitude or frequency-modulated spectral profiles including resonator distortions.

    PubMed

    Suter, Martin; Quack, Martin

    2015-05-10

    We report experiments and an improved method of analysis for any harmonics of frequency-modulated spectral line shapes allowing for very precise determinations of the resonance frequency of single absorption lines for gigahertz spectroscopy in the gas phase. Resonator perturbations are implemented into the formalism of modulation spectroscopy by means of a full complex transmission function being able to model the asymmetrically distorted absorption line shapes for arbitrary modulation depths, modulation frequencies, and resonator reflectivities. Exact equations of the in-phase and the quadrature modulation signal, taking into account a full resonator transmission function, are simultaneously adjusted to two-channel lock-in measurements performed in the gigahertz regime to obtain the spectral line position. The determination of the absorption line position of the rotational transition J' = 7 ← J" = 6 of (16)O(12)C(32)S in the vibrational ground state is investigated while changing the resonator distortions. The results are subjected to the approach proposed here and compared to standard methods known from the literature.

  15. Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering

    SciTech Connect

    Barbara Pasquini; Marc Vanderhaeghen

    2004-07-01

    We discuss the target and beam normal spin asymmetries in elastic electron-nucleon scattering which depend on the imaginary part of two-photon exchange processes between electron and nucleon. We express this imaginary part as a phase space integral over the doubly virtual Compton scattering tensor on the nucleon. We use unitarity to model the doubly virtual Compton scattering tensor in the resonance region in terms of {gamma}* N {yields} {pi} N electroabsorption amplitudes. Taking those amplitudes from a phenomenological analysis of pion electroproduction observables, we present results for beam and target normal single spin asymmetries for elastic electron-nucleon scattering for beam energies below 1 GeV and in the 1-3 GeV region, where several experiments are performed or are in progress.

  16. Development of a graphite polarization analyzer for resonant inelastic x-ray scattering

    SciTech Connect

    Gao Xuan; Burns, Clement; Li Chengyang; Casa, Diego; Upton, Mary; Gog, Thomas; Kim, Jungho

    2011-11-15

    Resonant inelastic x-ray scattering (RIXS) is a powerful technique for studying electronic excitations in correlated electron systems. Current RIXS spectrometers measure the changes in energy and momentum of the photons scattered by the sample. A powerful extension of the RIXS technique is the measurement of the polarization state of the scattered photons which contains information about the symmetry of the excitations. This long-desired addition has been elusive because of significant technical challenges. This paper reports the development of a new diffraction-based polarization analyzer which discriminates between linear polarization components of the scattered photons. The double concave surface of the polarization analyzer was designed as a good compromise between energy resolution and throughput. Such a device was fabricated using highly oriented pyrolytic graphite for measurements at the Cu K-edge incident energy. Preliminary measurements on a CuGeO{sub 3} sample are presented.

  17. Research on local resonance and Bragg scattering coexistence in phononic crystal

    NASA Astrophysics Data System (ADS)

    Dong, Yake; Yao, Hong; Du, Jun; Zhao, Jingbo; Jiang, Jiulong

    2017-04-01

    Based on the finite element method (FEM), characteristics of the local resonance band gap and the Bragg scattering band gap of two periodically-distributed vibrator structures are studied. Conditions of original anti-resonance generation are theoretically derived. The original anti-resonance effect leads to localization of vibration. Factors which influence original anti-resonance band gap are analyzed. The band gap width and the mass ratio between two vibrators are closely correlated to each other. Results show that the original anti-resonance band gap has few influencing factors. In the locally resonant structure, the Bragg scattering band gap is found. The mass density of the elastic medium and the elasticity modulus have an important impact on the Bragg band gap. The coexistence of the two mechanisms makes the band gap larger. The band gap covered 90% of the low frequencies below 2000 Hz. All in all, the research could provide references for studying the low-frequency and broad band gap of phononic crystal.

  18. Advanced Spectral Analysis Methods for Quantification of Coherent Ultrasound Scattering: Applications in the Breast

    NASA Astrophysics Data System (ADS)

    Rosado-Mendez, Ivan M.

    The goal of this dissertation was to improve the diagnostic value of parametric images generated from Quantitative Ultrasound (QUS) methods based on the power spectral density (PSD) of radiofrequency echo signals. This was achieved by testing for local adherence to conventional QUS assumptions that echo signals originate from incoherent scattering, and that signals are stationary over PSD estimation windows. For this purpose, we designed a novel algorithm that empirically evaluates the statistical significance of coherent-scattering signatures in the echo signals. Signatures are quantified through a set of optimized metrics describing the stationary or non-stationary features of the echo signals. We compared Nakagami-model based metrics and model-free metrics of the statistics of the echo signal amplitude for analyzing stationary features. For non-stationary features, we advanced the use of the echo-signal generalized spectrum by comparing single- and multi-taper estimators of this spectrum to the time-domain singular spectrum analysis method. Tests of statistical significance were done through empirical comparisons with values of the same metrics estimated from a uniform reference material exhibiting incoherent scattering. The metrics that quantify these features were selected after simulation- and phantom-based optimizations centered on the task of creating parametric images, where tradeoffs must be made between spatial resolution and detection performance. The connection of the analyses of the stationary and the non-stationary features provided a way to estimate descriptors of the tissue organization scales below and above the resolution limit imposed by the size of the acoustic pulse. A preliminary application of the developed algorithm was done on echo data from human breast lesions scanned in vivo. Results supported the idea of a more homogeneously random distribution of subresolution scatterers within invasive ductal carcinomas than within fibroadenomas

  19. Upgrades to improve the usability, reliability, and spectral range of the MST Thomson scattering diagnostic

    NASA Astrophysics Data System (ADS)

    Kubala, S. Z.; Borchardt, M. T.; Den Hartog, D. J.; Holly, D. J.; Jacobson, C. M.; Morton, L. A.; Young, W. C.

    2016-11-01

    The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV-5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1 kHz-25 kHz. Several subsystems of the diagnostic are being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being replaced to improve usability, reliability, and maintainability. Each of the 144 APDs will have an individual rack mounted switching supply, with bias voltage adjustable to match the APD. Long-wavelength filters (1140 nm center, 80 nm bandwidth) have been added to the polychromators to improve capability to resolve non-Maxwellian distributions and to enable directed electron flow measurements. A supercontinuum (SC) pulsed white light source has replaced the tungsten halogen lamp previously used for spectral calibration of the polychromators. The SC source combines substantial brightness produced in nanosecond pulses with a spectrum that covers the entire range of the polychromators.

  20. Upgrades to improve the usability, reliability, and spectral range of the MST Thomson scattering diagnostic.

    PubMed

    Kubala, S Z; Borchardt, M T; Den Hartog, D J; Holly, D J; Jacobson, C M; Morton, L A; Young, W C

    2016-11-01

    The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV-5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1 kHz-25 kHz. Several subsystems of the diagnostic are being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being replaced to improve usability, reliability, and maintainability. Each of the 144 APDs will have an individual rack mounted switching supply, with bias voltage adjustable to match the APD. Long-wavelength filters (1140 nm center, 80 nm bandwidth) have been added to the polychromators to improve capability to resolve non-Maxwellian distributions and to enable directed electron flow measurements. A supercontinuum (SC) pulsed white light source has replaced the tungsten halogen lamp previously used for spectral calibration of the polychromators. The SC source combines substantial brightness produced in nanosecond pulses with a spectrum that covers the entire range of the polychromators.

  1. Spectral light separator based on deep-subwavelength resonant apertures in a metallic film

    SciTech Connect

    Büyükalp, Yasin; Catrysse, Peter B. Shin, Wonseok; Fan, Shanhui

    2014-07-07

    We propose to funnel, select, and collect light spectrally by exploiting the unique properties of deep-subwavelength resonant apertures in a metallic film. In our approach, each aperture has an electromagnetic cross section that is much larger than its physical size while the frequency of the collected light is controlled by its height through the Fabry-Pérot resonance mechanism. The electromagnetic crosstalk between apertures remains low despite physical separations in the deep-subwavelength range. The resulting device enables an extremely efficient, subwavelength way to decompose light into its spectral components without the loss of photons and spatial coregistration errors. As a specific example, we show a subwavelength-size structure with three deep-subwavelength slits in a metallic film designed to operate in the mid-wave infrared range between 3 and 5.5 μm.

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

  3. Label-free pathology by spectrally sliced femtosecond stimulated Raman scattering (SRS) microscopy.

    PubMed

    Francis, Andrew; Berry, Kyla; Chen, Yikai; Figueroa, Benjamin; Fu, Dan

    2017-01-01

    Optical "virtual biopsy" is an attractive way to improve disease diagnosis and surgical guidance. Many optical microscopy techniques have been developed to provide diagnostic information without the need for tissue sectioning or staining. Among these techniques, label-free chemical imaging is the most desirable. Recently, it has been shown that narrowband, picosecond stimulated Raman scattering (SRS) can achieve comparable morphological contrast to hematoxylin and eosin staining (H&E staining), the 'gold standard' of pathology. However, to translate the technique from the bench to the bedside, optimal laser sources and parameters have yet to be identified. Here we describe an improvement to the narrowband SRS microscopy techniques for label-free tissue imaging. Through spectral slicing of broadband, femtosecond pulses, we are able to maintain the same protein/lipid contrast as narrowband SRS while achieving a higher signal-to-noise ratio (SNR). Our method draws upon the benefits of femtosecond pulses (e.g. higher peak power) while preserving those of picosecond pulses (e.g. adequate spectral resolution). We demonstrate this achievement through protein/lipid signal and contrast quantification of mouse brain tissue as a function of bandwidth, and comparison with numerical simulations. Further method validation is provided through imaging of additional mouse tissues: liver, kidney, and skin.

  4. Fast spectral coherent anti-Stokes Raman scattering microscopy with high-speed tunable picosecond laser.

    PubMed

    Cahyadi, Harsono; Iwatsuka, Junichi; Minamikawa, Takeo; Niioka, Hirohiko; Araki, Tsutomu; Hashimoto, Mamoru

    2013-09-01

    We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5  cm-1 in the Raman spectral region around 2850  cm-1 with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850  cm-1, corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid.

  5. High Resolution Resonant Inelastic Light Scattering from 185 to 900 nm

    NASA Astrophysics Data System (ADS)

    Rubhausen, Michael; Backstrom, Joakim; Schulz, Benjamin; Kruger, Rilana; Budelmann, Dirk

    2003-03-01

    We present the concept, design, and first results of a spectrally very agile Raman spectrometer that has a fully achromatic and parabolic focussing on the sample and an achromatic coupling into a spectrometer that operates in a wavelength range between 185 and 900 nm. Due to the diffraction limited imaging it features very high spectral and spatial resolution as well as excellent efficiency. A special spatial filter stage between the two subtractively coupled premonochromators allows very high straylight rejection even in the deep ultraviolett spectral range. This filter stage is also common to all systems previously developed in the 'ultimative triple' series by Miles Klein (Urbana-Champaign) and is shown here to be crucial for measurements in this difficult spectral range. First results of resonance Raman measurements on Silicon, LaMnO3 and the Keratin matrix are shown and compared with theoretical expectations.

  6. Hybridization and electron-phonon coupling in ferroelectric BaTiO3 probed by resonant inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Fatale, S.; Moser, S.; Miyawaki, J.; Harada, Y.; Grioni, M.

    2016-11-01

    We investigated the ferroelectric perovskite material BaTiO3 by resonant inelastic x-ray scattering (RIXS) at the Ti L3 edge. We observe with decreasing temperature a transfer of spectral weight from the elastic to the charge-transfer spectral features, indicative of increasing Ti 3 d -O 2 p hybridization. When the incident photon energy selects transitions to the Ti 3 d eg manifold, the quasielastic RIXS response exhibits a tail indicative of phonon excitations. A fit of the spectral line shape by a theoretical model allows us to estimate the electron-phonon coupling strength M ˜0.25 eV, which places BaTiO3 in the intermediate coupling regime.

  7. Observation of momentum-dependent charge excitations in hole-doped cuprates using resonant inelastic x-ray scattering at the oxygen K edge

    NASA Astrophysics Data System (ADS)

    Ishii, Kenji; Tohyama, Takami; Asano, Shun; Sato, Kentaro; Fujita, Masaki; Wakimoto, Shuichi; Tustsui, Kenji; Sota, Shigetoshi; Miyawaki, Jun; Niwa, Hideharu; Harada, Yoshihisa; Pelliciari, Jonathan; Huang, Yaobo; Schmitt, Thorsten; Yamamoto, Yoshiya; Mizuki, Jun'ichiro

    2017-09-01

    We investigate electronic excitations in La2 -x(Br,Sr ) xCuO4 using resonant inelastic x-ray scattering (RIXS) at the oxygen K edge. RIXS spectra of the hole-doped cuprates show clear momentum dependence below 1 eV. The broad spectral weight exhibits positive dispersion and shifts to higher energy with increasing hole concentration. Theoretical calculation of the dynamical charge structure factor on oxygen orbitals in a three-band Hubbard model is consistent with the experimental observation of the momentum and doping dependence, and therefore the momentum-dependent spectral weight is ascribed to intraband charge excitations which have been observed in electron-doped cuprates. Our results confirm that the momentum-dependent charge excitations exist on the order of the transfer energy (t ), and the broad spectral line shape indicates damped and incoherent character of the charge excitations at the energy range in the doped Mott insulators.

  8. Study of proton resonance structure in {sup 27}P via resonant elastic scattering of {sup 26}Si+p

    SciTech Connect

    Jung, H. S.; Lee, C. S.; Kwon, Y. K.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; and others

    2012-11-12

    A measurement of resonant elastic scattering of {sup 26}Si+p was performed with a thick target using a {sup 26}Si radioactive ion beam at the CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study (CNS), the University of Tokyo. The excitation function of {sup 27}P was measured successfully with the inverse kinematics method through a covered the range of excitation energies from E{sub x}{approx} 2.3 to 3.8 MeV, providing information about the resonance structure of this nucleus. The properties of these resonances are important to better determine the production rates of {sup 26}Si(p,g){sup 27}P reaction, which is one of the astrophysically important nuclear reactions to understand the production of the {sup 26}Al. Some new resonant states have been investigated, and determined their resonance parameters, such as excitation energies, proton partial widths, and spin-parities by R-matrix calculation.

  9. Resonant scattering and resultant pitch angle evolution of relativistic electrons by plasmaspheric hiss

    NASA Astrophysics Data System (ADS)

    Ni, B.; Bortnik, J.; Thorne, R. M.; Ma, Q.; Chen, L.

    2013-12-01

    Adopting several realistic models for the wave distribution and ambient plasmaspheric density, we perform a comprehensive analysis to evaluate hiss-induced scattering coefficients, the relative role of each resonant harmonic, and the overall effect of hiss scattering on the pitch angle evolution and associated decay (loss) processes of relativistic electrons. The results show that scattering by the equatorial, highly oblique component of the hiss emission is negligible. A quasi-parallel propagating wave model of hiss emissions provides a good approximation for evaluation of scattering rates of ≤ 2 MeV electrons. However, realistic wave propagation angles as a function of latitude along the field line must be taken into account to accurately quantify the rates of hiss scattering above 2 MeV. Ambient plasma density is also a critical parameter that can influence hiss scattering rates and resultant pitch angle evolution of electron flux. While the first order cyclotron and the Landau resonances are dominant for hiss-induced scattering of less than 2 MeV electrons, higher order resonances become important and even dominant at intermediate equatorial pitch angles for ultra-relativistic (≥ 3 MeV) electrons. Hiss induced electron pitch angle evolution consistently shows a relatively rapid initial transport of electrons from high to lower pitch angles, with a gradual approach towards an equilibrium shape, and a final state where the entire distribution decays exponentially with time. Although hiss scattering rates near the loss cone control the pitch angle evolution and the ultimate loss of ultra-relativistic electrons, the presence of a scattering bottleneck (a pronounced drop in diffusion rate at intermediate pitch angles) significantly affects the loss rate and leads to characteristic top hat shaped pitch angle distributions at energies below ~1 MeV. Decay timescales are determined to be on the order of a few days, tens of days, and > 100 days for 500 keV, 2 Me

  10. Single-photon switch: Controllable scattering of photons inside a one-dimensional resonator waveguide

    NASA Astrophysics Data System (ADS)

    Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.

    2010-03-01

    We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).

  11. Resonances in coupled πK, ηK scattering from lattice QCD

    SciTech Connect

    Wilson, David J.; Dudek, Jozef J.; Edwards, Robert G.; Thomas, Christopher E.

    2015-03-10

    Coupled-channel πK and ηK scattering amplitudes are determined by studying the finite-volume energy spectra obtained from dynamical lattice QCD calculations. Using a large basis of interpolating operators, including both those resembling a qq-bar construction and those resembling a pair of mesons with relative momentum, a reliable excited-state spectrum can be obtained. Working at mπ = 391 MeV, we find a gradual increase in the JP = 0+ πK phase-shift which may be identified with a broad scalar resonance that couples strongly to πK and weakly to ηK. The low-energy behavior of this amplitude suggests a virtual bound-state that may be related to the κ resonance. A bound state with JP = 1- is found very close to the πK threshold energy, whose coupling to the πK channel is compatible with that of the experimental K*(892). Evidence is found for a narrow resonance in JP = 2+. Isospin–3/2 πK scattering is also studied and non-resonant phase-shifts spanning the whole elastic scattering region are obtained.

  12. Resonances in coupled πK, ηK scattering from lattice QCD

    DOE PAGES

    Wilson, David J.; Dudek, Jozef J.; Edwards, Robert G.; ...

    2015-03-10

    Coupled-channel πK and ηK scattering amplitudes are determined by studying the finite-volume energy spectra obtained from dynamical lattice QCD calculations. Using a large basis of interpolating operators, including both those resembling a qq-bar construction and those resembling a pair of mesons with relative momentum, a reliable excited-state spectrum can be obtained. Working at mπ = 391 MeV, we find a gradual increase in the JP = 0+ πK phase-shift which may be identified with a broad scalar resonance that couples strongly to πK and weakly to ηK. The low-energy behavior of this amplitude suggests a virtual bound-state that may bemore » related to the κ resonance. A bound state with JP = 1- is found very close to the πK threshold energy, whose coupling to the πK channel is compatible with that of the experimental K*(892). Evidence is found for a narrow resonance in JP = 2+. Isospin–3/2 πK scattering is also studied and non-resonant phase-shifts spanning the whole elastic scattering region are obtained.« less

  13. Redistribution of light frequency by multiple scattering in a resonant atomic vapor

    NASA Astrophysics Data System (ADS)

    Carvalho, João Carlos de A.; Oriá, Marcos; Chevrollier, Martine; Cavalcante, Hugo L. D. de Souza; Passerat de Silans, T.

    2015-05-01

    The propagation of light in a resonant atomic vapor can a priori be thought of as a multiple scattering process, in which each scattering event redistributes both the direction and the frequency of the photons. Particularly, the frequency redistribution may result in Lévy flights of photons, directly affecting the transport properties of light in a resonant atomic vapor and turning this propagation into a superdiffusion process. Here, we report on a Monte Carlo simulation developed to study the evolution of the spectrum of the light in a resonant thermal vapor. We observe the gradual change of the spectrum and its convergence towards a regime of complete frequency redistribution as the number of scattering events increases. We also analyze the probability density function of the step length of photons between emissions and reabsorptions in the vapor, which governs the statistics of the light diffusion. We observe two different regimes in the light transport: superdiffusion when the vapor is excited near the line center and normal diffusion for excitation far from the line center. The regime of complete frequency redistribution is not reached for excitation far from resonance even after many absorption and reemission cycles due to correlations between emitted and absorbed frequencies.

  14. Plasmon resonant gold-coated liposomes for spectrally controlled content release

    NASA Astrophysics Data System (ADS)

    Leung, Sarah J.; Bobnick, Michael C.; Romanowski, Marek

    2010-02-01

    We recently demonstrated that liposome-supported plasmon resonant gold nanoshells are degradable into components of a size compatible with renal clearance, potentially enabling their use as multifunctional agents in applications in nanomedicine, including imaging, diagnostics, therapy, and drug delivery (Troutman et al., Adv. Mater. 2008, 20, 2604-2608). When illuminated with laser light at the wavelength matching their plasmon resonance band, gold-coated liposomes rapidly release their encapsulated substances, which can include therapeutic and diagnostic agents. The present research demonstrates that release of encapsulated agents from gold-coated liposomes can be spectrally controlled by varying the location of the plasmon resonance band; this spectral tuning is accomplished by varying the concentration of gold deposited on the surface of liposomes. Furthermore, the amount of laser energy required for release is qualitatively explained using the concept of thermal confinement (Jacques, Appl. Opt. 1993, 32(3), 2447-2454). Overlapping thermal confinement zones can be avoided by minimizing the laser pulse width, resulting in lower energy requirements for liposomal content release and less global heating of the sample. Control of heating is especially important in drug delivery applications, where it enables spatial and spectral control of delivery and prevents thermal damage to tissue.

  15. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

    SciTech Connect

    Braicovich, L. Minola, M.; Dellea, G.; Ghiringhelli, G.; Le Tacon, M.; Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B.; Supruangnet, R.

    2014-11-15

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

  16. Non-resonant Mie scattering: Emergent optical properties of core-shell polymer nanowires

    PubMed Central

    Khudiyev, Tural; Huseyinoglu, Ersin; Bayindir, Mehmet

    2014-01-01

    We provide the in-depth characterization of light-polymer nanowire interactions in the context of an effective Mie scattering regime associated with low refractive index materials. Properties of this regime sharply contrast with these of resonant Mie scattering, and involve the formation of strictly forward-scattered and coupling-free optical fields in the vicinity of core-shell polymer nanowires. Scattering from these optical fields is shown to be non-resonant in nature and independent from incident polarization. In order to demonstrate the potential utility of this scattering regime in one-dimensional (1D) polymeric nanostructures, we fabricate polycarbonate (PC) - polyvinylidene difluoride (PVDF) core-shell nanowires using a novel iterative thermal drawing process that yields uniform and indefinitely long core-shell nanostructures. These nanowires are successfully engineered for novel nanophotonics applications, including size-dependent structural coloration, efficient light capture on thin-film solar cells, optical nano-sensors with ultrahigh sensitivity and a mask-free photolithography method suitable for the straightforward production of 1D nanopatterns. PMID:24714206

  17. Resonant scattering and microscopic model of spinless Fermi gases in one-dimensional optical lattices

    NASA Astrophysics Data System (ADS)

    Cui, Xiaoling

    2017-04-01

    We study the effective Bloch-wave scattering of a spinless Fermi gas in one-dimensional (1D) optical lattices. By tuning the odd-wave scattering length, we find multiple resonances of Bloch waves scattering at the bottom (and the top) of the lowest band, beyond which an attractive (and a repulsive) two-body bound state starts to emerge. These resonances exhibit comparable widths in the deep lattice limit, and the finite interaction range plays an essential role in determining their locations. Based on exact two-body solutions, we construct an effective microscopic model for the low-energy scattering of fermions. The model can reproduce not only the scattering amplitudes of Bloch waves at the lowest-band bottom or top, but also the attractive or repulsive bound states within a reasonably large energy range below or above the band. These results lay the foundation for quantum simulating topological states in cold Fermi gases confined in 1D optical lattices.

  18. On the influence of resonant scattering on cosmic microwave background polarization anisotropies

    NASA Astrophysics Data System (ADS)

    Hernández-Monteagudo, C.; Rubiño-Martín, J. A.; Sunyaev, R. A.

    2007-10-01

    We implement the theory of resonant scattering in the context of cosmic microwave background (CMB) polarization anisotropies. We compute the changes in the E-mode polarization (EE) and temperature E-mode (TE) CMB power spectra introduced by the scattering on a resonant transition with a given optical depth τX and polarization coefficient E1. The latter parameter, accounting for how anisotropic the scattering is, depends on the exchange of angular momentum in the transition, enabling observational discrimination between different resonances. We use this formalism in two different scenarios: cosmological recombination and cosmological re-ionization. In the context of cosmological recombination, we compute predictions in frequency and multipole space for the change in the TE and EE power spectra introduced by scattering on the Hα and Pα lines of hydrogen. This constitutes a fundamental test of the standard model of recombination, and the sensitivity it requires is comparable to that needed in measuring the primordial CMB B-mode polarization component. In the context of re-ionization, we study the scattering off metals and ions produced by the first stars, and find that polarization anisotropies, apart from providing a consistency test for intensity measurements, give some insight on how re-ionization evolved. Since polarization anisotropies have memory of how anisotropic the line scattering is, they should be able to discern the OI 63.2-μm transition from other possible transitions associated to OIII, NII, NIII, etc. The amplitude of these signals are, however, between 10 and 100 times below the (already challenging) level of CMB B-mode polarization anisotropies.

  19. A combination of dynamic light scattering and polarized resonance Raman scattering applied in the study of Arenicola Marina extracellular hemoglobin.

    PubMed

    Jernshøj, K D; Hassing, S; Olsen, L F

    2013-08-14

    Arenicola Marina extracellular hemoglobin (Hbl Hb) is considered to be a promising candidate as a blood substitute. To entangle some of the properties of extracellular giant hexagonal bilayer hemoglobin (Hbl Hb) of Arenicola Marina, we combined polarized resonance Raman scattering (532 nm excitation) with dynamic light scattering (DLS) (632.8 nm). An analysis of the depolarization ratio of selected a(2g) skeletal modes of the heme in native Hbl Hb and porcine Hb, shows that the distortion of the heme group away from its ideal fourfold symmetry is much smaller for heme groups bound in the Hbl Hb than for heme groups bound in porcine Hb. Using DLS, the average hydrodynamic diameter () of Hbl Hb was measured at pH = 5, 7, 8, 9, and 10. At pH = 5 to 7, the Hbl Hb was found in its native form with equal to 24.2 nm, while at pH = 8 and 9, a dissociation process starts to take place resulting in = 9 nm. At pH = 10, only large aggregates of fragmented Hbl Hb with larger than 1000 nm was detected, however, a comparison of the DLS results with the polarized resonance Raman scattering (RRS) revealed that the coupling between the fragments did not involve direct interaction between the heme groups, but also that the local heme environment seems to be comparable in the aggregates and in the native Hbl Hb. By comparing the unpolarized RRS results obtained for erythrocytes (RBC) with those for Hbl Hb, led us to the important conclusion that Hbl Hb is much easier photolyzed than porcine RBC.

  20. A combination of dynamic light scattering and polarized resonance Raman scattering applied in the study of Arenicola Marina extracellular hemoglobin

    NASA Astrophysics Data System (ADS)

    Jernshøj, K. D.; Hassing, S.; Olsen, L. F.

    2013-08-01

    Arenicola Marina extracellular hemoglobin (Hbl Hb) is considered to be a promising candidate as a blood substitute. To entangle some of the properties of extracellular giant hexagonal bilayer hemoglobin (Hbl Hb) of Arenicola Marina, we combined polarized resonance Raman scattering (532 nm excitation) with dynamic light scattering (DLS) (632.8 nm). An analysis of the depolarization ratio of selected a2g skeletal modes of the heme in native Hbl Hb and porcine Hb, shows that the distortion of the heme group away from its ideal fourfold symmetry is much smaller for heme groups bound in the Hbl Hb than for heme groups bound in porcine Hb. Using DLS, the average hydrodynamic diameter (⟨dh⟩) of Hbl Hb was measured at pH = 5, 7, 8, 9, and 10. At pH = 5 to 7, the Hbl Hb was found in its native form with ⟨dh⟩ equal to 24.2 nm, while at pH = 8 and 9, a dissociation process starts to take place resulting in ⟨dh⟩ = 9 nm. At pH = 10, only large aggregates of fragmented Hbl Hb with ⟨dh⟩ larger than 1000 nm was detected, however, a comparison of the DLS results with the polarized resonance Raman scattering (RRS) revealed that the coupling between the fragments did not involve direct interaction between the heme groups, but also that the local heme environment seems to be comparable in the aggregates and in the native Hbl Hb. By comparing the unpolarized RRS results obtained for erythrocytes (RBC) with those for Hbl Hb, led us to the important conclusion that Hbl Hb is much easier photolyzed than porcine RBC.

  1. The phononic band gaps of Bragg scattering and locally resonant pentamode metamaterials

    NASA Astrophysics Data System (ADS)

    Cai, Chengxin; Wang, Zhaohong; Chu, Yangyang; Liu, Guangshun; Xu, Zhuo

    2017-10-01

    In this paper, the phononic band structures of Bragg scattering and locally resonant pentamode metamaterials (PMs) with single and composite materials symmetric double-cone elements (SDCEs) are calculated by using the finite element method. The numerical results show that, for the Bragg scattering PMs with single material SDCEs, the phononic band gaps (PBGs) can be obtained while the top touch cone diameters (TTCDs) (i.e. d) are much smaller than the bottom touch cone diameters (i.e. D), and the variation range of the PBGs frequency is mainly determined by the TTCDs. This indicates that the Bragg scattering PMs with single material SDCEs can be investigated as a phonon crystal. On this basis, the locally resonant SDCE PMs can be designed by using the composite SDCEs instead of single material SDCEs, and the PBGs can be obtained under the 100 Hz. This finding provides a way to control the low-frequency acoustics waves by using small-sized SDCEs PMs. In addition, compared with the Bragg scattering PMs, the relative bandwidth of the first PBGs of the locally resonant PMs can be expanded at least 25 times. In the end, the effect of mass density ~ρ and Young’s modulus E of the composition material parameters of locally resonant SDCEs PMs on the PBGs is also studied by changing the parameters individually. The results show that the lower and upper edge and relative bandwidth of the first PBGs of locally resonant PMs with composite SDCEs are mainly impacted by the difference of the mass density ρ between the two constituent materials, and the difference of the Young’s modulus E between the two constituent materials has little effect on the PBGs.

  2. Acoustic resonance scattering from a multilayered cylindrical shell with imperfect bonding.

    PubMed

    Rajabi, M; Hasheminejad, Seyyed M

    2009-12-01

    The method of wave function expansion is adopted to study the three dimensional scattering of a time-harmonic plane progressive sound field obliquely incident upon a multi-layered hollow cylinder with interlaminar bonding imperfection. For the generality of solution, each layer is assumed to be cylindrically orthotropic. An approximate laminate model in the context of the modal state equations with variable coefficients along with the classical T-matrix solution technique is set up for each layer to solve for the unknown modal scattering and transmission coefficients. A linear spring model is used to describe the interlaminar adhesive bonding whose effects are incorporated into the global transfer matrix by introduction of proper interfacial transfer matrices. Following the classic acoustic resonance scattering theory (RST), the scattered field and response to surface waves are determined by constructing the partial waves and obtaining the non-resonance (backgrounds) and resonance components. The solution is first used to investigate the effect of interlayer imperfection of an air-filled and water submerged bilaminate aluminium cylindrical shell on the resonances associated with various modes of wave propagation (i.e., symmetric/asymmetric Lamb waves, fluid-borne A-type waves, Rayleigh and Whispering Gallery waves) appearing in the backscattered spectrum, according to their polarization and state of stress. An illustrative numerical example is also given for a multi-layered (five-layered) cylindrical shell for which the stiffness of the adhesive interlayers is artificially varied. The sensitivity of resonance frequencies associated with higher mode numbers to the stiffness coefficients is demonstrated to be a good measure of the bonding strength. Limiting cases are considered and fair agreements with solutions available in the literature are established.

  3. Spectral implementation of some quantum algorithms by one- and two-dimensional nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Das, Ranabir; Kumar, Anil

    2004-10-01

    Quantum information processing has been effectively demonstrated on a small number of qubits by nuclear magnetic resonance. An important subroutine in any computing is the readout of the output. "Spectral implementation" originally suggested by Z. L. Madi, R. Bruschweiler, and R. R. Ernst [J. Chem. Phys. 109, 10603 (1999)], provides an elegant method of readout with the use of an extra "observer" qubit. At the end of computation, detection of the observer qubit provides the output via the multiplet structure of its spectrum. In spectral implementation by two-dimensional experiment the observer qubit retains the memory of input state during computation, thereby providing correlated information on input and output, in the same spectrum. Spectral implementation of Grover's search algorithm, approximate quantum counting, a modified version of Berstein-Vazirani problem, and Hogg's algorithm are demonstrated here in three- and four-qubit systems.

  4. Isomer Specific Microwave Spectrum of - and - Phenylvinylnitrile. Implementing a New Multi-Resonant Spectral Analysis Tool.

    NASA Astrophysics Data System (ADS)

    Hernandez-Castillo, Alicia O.; Hays, Brian M.; Abeysekera, Chamara; Zwier, Timothy S.

    2016-06-01

    There are many circumstances in modern microwave spectroscopy where the observed spectra contain contributions from many distinct sub-populations, creating a complicated spectrum with interleaved transitions due to its components making spectral assignment challenging. A new method, exploiting multi resonance effects with broadband CP-FTMW was developed and implemented to differentiate the structural isomers: (E)- and (Z)-phenylvinylnitrile. This method will output an exclusive set of isomer-specific transitions reducing the spectral assignment time. Details of the method implementation and structural analysis of the two-isomer mixture will be discussed. The application of the method to other circumstances where selective modulation of the transitions due to a single set of connected transitions is vital for complex spectral assignment, will also be considered.

  5. Local burst model of CMB temperature fluctuations: Scattering in the resonance lines of primordial hydrogen and helium.

    NASA Astrophysics Data System (ADS)

    Dubrovich, V. K.; Grachev, S. I.

    2016-11-01

    The propagation of an instantaneous burst of isotropic radiation from the time of its onset at some redshift z0 to the time of its detection at the present epoch (at z = 0) is considered within the framework of a flat Universe. The Thomson scattering by free electrons and the scattering in the primordial hydrogen Lα and Lβ lines and in the He I 1s2-1s2p, 1s3p (1S-1P*) lines are taken into account. It is shown that the relative amplitude of the spectral distortions due to the scattering in these lines at the corresponding frequencies can be a factor of 103-104 greater than the maximum possible amplitude from the scattering in the subordinate hydrogen lines considered previously (Dubrovich and Grachev 2015). In the linear approximation in optical depth, the distortion profiles in the resonance lines turn out to be purely absorption ones and depend neither on the direction nor on the distance to the burst center, in contrast to the profiles in the subordinate lines. The profiles contain jumps at frequencies corresponding to the instant the source (burst) appears at a given redshift z0. For example, at z0 = 5000 the jumps in the hydrogen Lα and Lβ lines lie at frequencies of 493 and 584 GHz, respectively, while in the above two helium lines they lie at frequencies of 855 and 930 GHz at z0 = 6000. The relative magnitude of the jumps ranges from 10-4 to 3 × 10-3.

  6. Extrinsic spin Hall effect induced by resonant skew scattering in graphene.

    PubMed

    Ferreira, Aires; Rappoport, Tatiana G; Cazalilla, Miguel A; Castro Neto, A H

    2014-02-14

    We show that the extrinsic spin Hall effect can be engineered in monolayer graphene by decoration with small doses of adatoms, molecules, or nanoparticles originating local spin-orbit perturbations. The analysis of the single impurity scattering problem shows that intrinsic and Rashba spin-orbit local couplings enhance the spin Hall effect via skew scattering of charge carriers in the resonant regime. The solution of the transport equations for a random ensemble of spin-orbit impurities reveals that giant spin Hall currents are within the reach of the current state of the art in device fabrication. The spin Hall effect is robust with respect to thermal fluctuations and disorder averaging.

  7. Investigations of thin films on GaAs using the proton resonant scattering technique

    NASA Astrophysics Data System (ADS)

    Yu, Kin Man; Jaklevic, J. M.; Haller, E. E.

    1988-04-01

    We have characterized a number of thermally stable thin film/GaAs systems including thin films of refractory metal suicides and nitrides as well as dielectric films on GaAs substrates using a MeV proton scattering technique. Thin films of tungsten suicides, zirconium nitride and silicon dioxide on GaAs substrates are investigated. The enhanced proton scattering cross sections of nitrogen, silicon and oxygen at their corresponding resonant energies enable us to accurately measure the compositions of these films. The advantages and disadvantages of this technique regarding depth resolution, accessible depth, and mass resolution compared to the conventional Rutherford backscattering spectrometry for thin film analysis are discussed.

  8. Possible detection of a cyclotron resonance scattering feature in the X-ray pulsar 4U 1909+07

    SciTech Connect

    Jaisawal, Gaurava K.; Naik, Sachindra; Paul, Biswajit

    2013-12-10

    We present timing and broad band spectral studies of the high-mass X-ray binary pulsar 4U 1909+07 using data from Suzaku observations during 2010 November 2-3. The pulse period of the pulsar is estimated to be 604.11 ± 0.14 s. Pulsations are seen in the X-ray light curve up to ∼70 keV. The pulse profile is found to be strongly energy-dependent: a complex, multi-peaked structure at low energy becomes a simple single peak at higher energy. We found that the 1-70 keV pulse-averaged continuum can be fit by the sum of a blackbody and a partial covering Negative and Positive power law with Exponential cutoff model. A weak iron fluorescence emission line at 6.4 keV was detected in the spectrum. An absorption-like feature at ∼44 keV was clearly seen in the residuals of the spectral fitting, independent of the continuum model adopted. To check the possible presence of a cyclotron resonance scattering feature (CRSF) in the spectrum, we normalized the pulsar spectrum with the spectrum of the Crab Nebula. The resulting Crab ratio also showed a clear dip centered at ∼44 keV. We performed statistical tests on the residuals of the spectral fitting and also on the Crab spectral ratio to determine the significance of the absorption-like feature and identified it as a CRSF of the pulsar. We estimated the corresponding surface magnetic field of the pulsar to be 3.8 × 10{sup 12} G.

  9. Spectral statistics of molecular resonances in erbium isotopes: How chaotic are they?

    NASA Astrophysics Data System (ADS)

    Mur-Petit, Jordi; Molina, Rafael A.

    2015-10-01

    We perform a comprehensive analysis of the spectral statistics of the molecular resonances in 166Er and 168Er observed in recent ultracold collision experiments [Frisch et al., Nature (London) 507, 475 (2014), 10.1038/nature13137] with the aim of determining the chaoticity of this system. We calculate different independent statistical properties to check their degree of agreement with random matrix theory (RMT), and analyze if they are consistent with the possibility of having missing resonances. The analysis of the short-range fluctuations as a function of the magnetic field points to a steady increase of chaoticity until B ˜30 G. The repulsion parameter decreases for higher magnetic fields, an effect that can be interpreted as due to missing resonances. The analysis of long-range fluctuations allows us to be more quantitative and estimate a 20 %-25 % fraction of missing levels. Finally, a study of the distribution of resonance widths provides additional evidence supporting missing resonances of small width compared with the experimental magnetic field resolution. We conclude that further measurements with increased resolution will be necessary to give a final answer to the problem of missing resonances and the agreement with RMT.

  10. Wide free-spectral-range triple ring resonator as optical filter

    NASA Astrophysics Data System (ADS)

    Dey, Sabitabrata; Mandal, S.

    2011-08-01

    A waveguide-based wide free-spectral-range (FSR) triple ring resonator (TRR) as an optical filter has been investigated in this article. The transmittance of the TRR is presented in Z-domain. The delay line signal processing approach and Mason's gain formula have been used to develop the transmittance of the TRR. The TRR in the article is capable of providing an FSR up to 605 GHz with lower crosstalk limited within -10 dB. Another efficacious scheme of TRR with much wider FSR of 1029 GHz and with reduced unit delay length is presented in the article. Here also crosstalk, as well as resonance loss, remains within reasonable limits. The FSRs obtained using the present TRR architectures in this work are until now reported as maximum for a corresponding class of optical ring resonators. The issues of group delay and dispersion, two important parameters associated with high frequency optical communication have been addressed in this article.

  11. Resonant x-ray scattering study of the antiferroelectric and ferrielectric phases in liquid crystal devices

    SciTech Connect

    Matkin, L. S.; Watson, S. J.; Gleeson, H. F.; Pindak, R.; Pitney, J.; Johnson, P. M.; Huang, C. C.; Barois, P.; Levelut, A.-M.; Srajer, G.

    2001-08-01

    Resonant x-ray scattering has been used to investigate the interlayer ordering of the antiferroelectric and ferrielectric smectic C{sup *} subphases in a device geometry. The liquid crystalline materials studied contain a selenium atom and the experiments were carried out at the selenium K edge allowing x-ray transmission through glass. The resonant scattering peaks associated with the antiferroelectric phase were observed in two devices containing different materials. It was observed that the electric-field-induced antiferroelectric to ferroelectric transition coincides with the chevron to bookshelf transition in one of the devices. Observation of the splitting of the antiferroelectric resonant peaks as a function of applied field also confirmed that no helical unwinding occurs at fields lower than the chevron to bookshelf threshold. Resonant features associated with the four-layer ferrielectric liquid crystal phase were observed in a device geometry. Monitoring the electric field dependence of these ferrielectric resonant peaks showed that the chevron to bookshelf transition occurs at a lower applied field than the ferrielectric to ferroelectric switching transition.

  12. Grading of apples based on firmness and soluble solids content using VIS-SWNIR spectroscopy and spectral scattering techniques

    USDA-ARS?s Scientific Manuscript database

    Sorting apple fruit based on internal quality will enhance the industry’s competiveness and profitability and assure consumer satisfaction. In this research, visible and shortwave near-infrared (Vis-SWNIR) spectroscopy (460–1,100 nm) and spectral scattering (450–1,050 nm) were used for sorting apple...

  13. Protecting EFIE-based scattering computations from effects of interior resonances

    NASA Astrophysics Data System (ADS)

    Canning, Francis X.

    1991-11-01

    A numerical method, based on the standard matrix formulation of the electric field integral equation (EFIE) for calculating the scattering from conducting bodies near resonant frequencies, is given for both stabilizing the numerical calculations and finding the form of the resonant fields. When this method is used along with a direct solution to the original matrix equation, it requires insignificant additional computation. An additional advantage of this approach is that it can easily be implemented in existing computer codes by using a single, standard but general, plug-in module.

  14. Resonant inelastic x-ray scattering studies of the organic semiconductor copper phthalocyanine

    SciTech Connect

    Kodituwakku, C. N.; Burns, C. A.; Said, A. H.; Sinn, H.; Wang, X.; Gog, T.; Casa, D. M.; Tuel, M.; Western Michigan Univ.; DESY, Hasylab

    2008-01-01

    We report resonant inelastic x-ray scattering (RIXS) measurements on polycrystalline and single crystal samples of the organic semiconductor {beta}-copper phthalocyanine (CuPc) as well as time dependent density functional theory calculations of the electronic properties of the CuPc molecule. Resonant and nonresonant excitations were measured along the three crystal axes with 120 meV resolution. We observe molecular excitations as well as charge-transfer excitons along certain crystal directions and compare our data with the calculations. Our results demonstrate that RIXS is a powerful tool for studying excitons and other electronic excitations in organic semiconductors.

  15. Resonant electron scattering by molecules adsorbed on a surface: N2-Ag system

    NASA Astrophysics Data System (ADS)

    Teillet-Billy, D.; Djamo, V.; Gauyacq, J. P.

    1992-05-01

    A model study of resonant electron scattering by static molecules adsorbed on a metal surface is presented, using the recently developed coupled angular mode (CAM) method. It is applied to the case of N2 molecules adsorbed on an Ag surface. The N2-2πg resonance characteristics (energy position and width) are determined and shown to be modified by the presence of the surface in qualitative agreement with the experimental results of Demuth et al. [Phys. Rev. Lett. 47 (1981) 1166].

  16. Detection of acetylene by electronic resonance-enhanced coherent anti-Stokes Raman scattering

    NASA Astrophysics Data System (ADS)

    Chai, N.; Naik, S. V.; Kulatilaka, W. D.; Laurendeau, N. M.; Lucht, R. P.; Roy, S.; Gord, J. R.

    2007-06-01

    We report the detection of acetylene (C2H2) at low concentrations by electronic resonance-enhanced coherent anti-Stokes Raman scattering (ERE-CARS). Visible pump and Stokes beams are tuned into resonance with Q-branch transitions in the v2 Raman band of acetylene. An ultraviolet probe beam is tuned into resonance with the tilde{A}-tilde{X} electronic transition of C2H2, resulting in significant electronic resonance enhancement of the CARS signal. The signal is found to increase significantly with rising pressure for the pressure range 0.1-8 bar at 300 K. Collisional narrowing of the spectra appears to be important at 2 bar and above. A detection limit of approximately 25 ppm at 300 K and 1 bar is achieved for our experimental conditions. The signal magnitudes and the shape of the C2H2 spectrum are essentially constant for UV probe wavelengths from 233.0 to 238.5 nm, thus indicating that significant resonant enhancement is achieved even without tuning the probe beam into resonance with a specific electronic resonance transition.

  17. Resonant X-ray scattering study of spinel Co2MnO4

    NASA Astrophysics Data System (ADS)

    Koo, Tae-Yeong; Lee, Dae-Su; Song, Jonghyun

    2014-11-01

    X-ray resonant enhancement of the (200) crystallographically forbidden reflection in the inverse cubic spinel Co2MnO4 single crystal is presented. Anisotropic X-ray scattering results near the K absorption edges of both Co and Mn ions observed in the azimuthal angle dependence are interpreted with the anisotropic tensorial character of the X-ray susceptibility. Spectra calculations including the various electric multipole transition channels, such as dipole-dipole ( E1- E1), dipole-quadrupole ( E1- E2), and quadrupole-quadrupole ( E2- E2), in two different polarization states of σ - σ and σ - π are discussed and compared with the experimental data to determine the channel of major contribution in the resonant scattering intensity.

  18. Quantitative surface-enhanced resonance Raman scattering of phthalocyanine-labelled oligonucleotides

    PubMed Central

    Macaskill, A.; Chernonosov, A. A.; Koval, V. V.; Lukyanets, E. A.; Fedorova, O. S.; Smith, W. E.; Faulds, K.; Graham, D.

    2007-01-01

    The evaluation of phthalocyanine labels for the surface-enhanced resonance Raman scattering (SERRS) detection of oligonucleotides is reported. Three phthalocyanine-labelled oligonucleotides were assessed, each containing a different metal centre. Detection limits for each labelled oligonucleotide were determined using two excitation frequencies where possible. Limits of detection as low as 2.8 × 10−11 mol. dm−3 were obtained which are comparable to standard fluorescently labelled probes used in previous SERRS studies. The identification of two phthalocyanine-labelled oligonucleotides without separation was also demonstrated indicating their suitability for multiplexing. This study extends the range of labels suitable for quantitative surface-enhanced resonance Raman scattering with silver nanoparticles and offers more flexibility and choice when considering SERRS for quantitative DNA detection. PMID:17289751

  19. Characterization of photosynthetic reaction centers by surface-enhanced resonance Raman scattering

    NASA Astrophysics Data System (ADS)

    Chumanov, George D.; Cotton, Therese M.; Zhou, Chengli; Gaul, Dale; Picorel, Rafael; Seibert, Michael

    1993-06-01

    Surface-enhanced Resonance Raman scattering (SERRS) spectra were obtained for the reaction center complexes of the photosynthetic bacterium Rhodobacter sphaeroides (RC) and from photosystem II (PSII) of spinach, adsorbed on Ag and Au surfaces. These preliminary results demonstrate the considerable potential of this technique for selectively exciting resonance Raman scattering from reaction center components within their distinct absorption bands. Because of the high sensitivity afforded by SERRS, spectra could be measured from a single monolayer of reaction centers adsorbed on a metal surface. The surface-sensitivity provides new information indicating the topology of the PSII reaction center 47 kD light-harvesting protein complex. The activity of the PSII reaction center complex adsorbed on metal surfaces was monitored by photochemical reduction of cyt b-559. Measurement of fluorescence emission was shown to be a new and sensitive method for monitoring the structural and functional integrity of the PSII reaction center complex on the metal surface.

  20. Strange resonance poles from Kπ scattering below 1.8 GeV

    NASA Astrophysics Data System (ADS)

    Pelaez, J. R.; Rodas, A.; Ruiz de Elvira, J.

    2017-02-01

    In this work we present a determination of the mass, width, and coupling of the resonances that appear in kaon-pion scattering below 1.8 GeV. These are: the much debated scalar κ -meson, nowadays known as K_0^*(800), the scalar K_0^*(1430), the K^*(892) and K_1^*(1410) vectors, the spin-two K_2^*(1430) as well as the spin-three K^*_3(1780). The parameters will be determined from the pole associated to each resonance by means of an analytic continuation of the Kπ scattering amplitudes obtained in a recent and precise data analysis constrained with dispersion relations, which were not well satisfied in previous analyses. This analytic continuation will be performed by means of Padé approximants, thus avoiding a particular model for the pole parameterization. We also pay particular attention to the evaluation of uncertainties.

  1. Coupled-channel model for K¯N scattering in the resonant region

    DOE PAGES

    Fernández-Ramírez, Cesar; Danilkin, Igor V.; Manley, D. Mark; ...

    2016-02-18

    Here, we present a unitary multichannel model formore » $$\\bar{K}$$N scattering in the resonance region that fulfills unitarity. It has the correct analytical properties for the amplitudes once they are extended to the complex-$s$ plane and the partial waves have the right threshold behavior. In order to determine the parameters of the model, we have fitted single-energy partial waves up to J = 7/2 and up to 2.15 GeV of energy in the center-of-mass reference frame obtaining the poles of the Λ* and Σ* resonances, which are compared to previous analyses. Furthermore, we provide the most comprehensive picture of the S = –1 hyperon spectrum to date. Here, important differences are found between the available analyses making the gathering of further experimental information on $$\\bar{K}$$N scattering mandatory to make progress in the assessment of the hyperon spectrum.« less

  2. An a0 resonance in strongly coupled π η , K K ¯ scattering from lattice QCD

    NASA Astrophysics Data System (ADS)

    Dudek, Jozef J.; Edwards, Robert G.; Wilson, David J.; Hadron Spectrum Collaboration

    2016-05-01

    We present the first calculation of coupled-channel meson-meson scattering in the isospin =1 , G -parity negative sector, with channels π η , K K ¯ and π η', in a first-principles approach to QCD. From the discrete spectrum of eigenstates in three volumes extracted from lattice QCD correlation functions we determine the energy dependence of the S -matrix, and find that the S -wave features a prominent cusplike structure in π η →π η close to the K K ¯ threshold coupled with a rapid turn-on of amplitudes leading to the K K ¯ final state. This behavior is traced to an a0(980 )-like resonance, strongly coupled to both π η and K K ¯ , which is identified with a pole in the complex energy plane, appearing on only a single unphysical Riemann sheet. Consideration of D -wave scattering suggests a narrow tensor resonance at higher energy.

  3. Refractive versus resonant diffraction scattering of loosely bound 6Li nuclei

    NASA Astrophysics Data System (ADS)

    Carstoiu, Florin; Trache, Livius

    2012-05-01

    We present a complete analysis of 6Li+16O elastic scattering at 4 and 5 MeV/nucleon. Using either traditional Woods-Saxon or a range of semimicroscopic folding form factors we find that the data require deep, highly transparent potentials. Physically relevant solutions are selected according to the dispersion relation. The intermediate angle structures and the oscillatory increase of the cross section at large angles are interpreted either as a pre-rainbow oscillation resulting from the interference of the barrier and internal barrier far-side scattering subamplitudes or, equally well, as a resonant diffraction arising from two Regge poles located in peripheral waves. Both semiclassical and Regge pole approaches allow a dynamical separation of the resonant component of the S matrix.

  4. Collective Nature of Spin Excitations in Superconducting Cuprates Probed by Resonant Inelastic X-Ray Scattering

    NASA Astrophysics Data System (ADS)

    Minola, M.; Dellea, G.; Gretarsson, H.; Peng, Y. Y.; Lu, Y.; Porras, J.; Loew, T.; Yakhou, F.; Brookes, N. B.; Huang, Y. B.; Pelliciari, J.; Schmitt, T.; Ghiringhelli, G.; Keimer, B.; Braicovich, L.; Le Tacon, M.

    2015-05-01

    We used resonant inelastic x-ray scattering (RIXS) with and without analysis of the scattered photon polarization, to study dispersive spin excitations in the high temperature superconductor YBa2Cu3O6 +x over a wide range of doping levels (0.1 ≤x ≤1 ). The excitation profiles were carefully monitored as the incident photon energy was detuned from the resonant condition, and the spin excitation energy was found to be independent of detuning for all x . These findings demonstrate that the largest fraction of the spin-flip RIXS profiles in doped cuprates arises from magnetic collective modes, rather than from incoherent particle-hole excitations as recently suggested theoretically [Benjamin et al. Phys. Rev. Lett. 112, 247002 (2014)]. Implications for the theoretical description of the electron system in the cuprates are discussed.

  5. Cluster structure of neutron-rich 10Be and 14C via resonant alpha scattering

    NASA Astrophysics Data System (ADS)

    Suzuki, D.; Ahn, T.; Bazin, D.; Becchetti, F. D.; Beceiro-Novo, S.; Fritsch, A.; Kolata, J. J.; Mittig, W.; AT-TPC Collaboration

    2017-09-01

    Neutron-rich ^{10} Be and ^{14} C nuclei were studied via resonant α scattering of radioactive 6 He and ^{10} Be beams, respectively, produced by the TwinSol facility at the University of Notre Dame. The Prototype Active-Target Time-Projection Chamber (pAT-TPC) was used as a thick gaseous α target to induce resonant scattering and as a device to track reacted particles inside the target, providing continuous excitation functions and angular distributions over a wide range of energies and angles. The experimental results indicate a melting phenomenon of α clusters in the 4+ rotational member of the ^{10} Be ground state and a linear chain alignment of three α clusters in ^{14} C excited states, as recently predicted by an anti-symmetrized molecular dynamics calculation.

  6. 12C+p resonant elastic scattering in the Maya active target

    NASA Astrophysics Data System (ADS)

    Sambi, S.; Raabe, R.; Borge, M. J. G.; Caamano, M.; Damoy, S.; Fernández-Domínguez, B.; Flavigny, F.; Fynbo, H.; Gibelin, J.; Grinyer, G. F.; Heinz, A.; Jonson, B.; Khodery, M.; Nilsson, T.; Orlandi, R.; Pancin, J.; Perez-Loureiro, D.; Randisi, G.; Ribeiro, G.; Roger, T.; Suzuki, D.; Tengblad, O.; Thies, R.; Datta, U.

    2015-03-01

    In a proof-of-principle measurement, the Maya active target detector was employed for a 12C( p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in 13N was investigated in a single measurement. By using the capability of the detector to localize the reaction vertex and record the tracks of the recoiling protons, data covering a large solid angle could be utilized, at the same time keeping an energy resolution comparable with that of direct-kinematics measurements. The excitation spectrum in 13N was fitted using the R-matrix formalism. The level parameters extracted are in good agreement with previous studies. The active target proved its potential for the study of resonant elastic scattering in inverse kinematics with radioactive beams, when detection efficiency is of primary importance.

  7. Behavior of trapped ultracold dilute Bose gases at large scattering length near a Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Lekala, M. L.; Chakrabarti, B.; Rampho, G. J.; Das, T. K.; Sofianos, S. A.; Adam, R. M.

    2014-02-01

    We calculate the ground-state energy and the collective excitation frequency of trapped bosons at large scattering length interacting via the realistic two-body van der Waals potential. Our many-body method keeps two-body correlations produced by all interacting pairs. When the scattering length is small compared to the trap size and the number of bosons in the trap is of the order of a few thousands, the mean-field results are in good agreement with the many-body results. However for large particle numbers, even when the condensate is sufficiently dilute, the interatomic correlation comes into the picture. When the scattering length is quite large near the Feshbach resonance, the Bose gas becomes highly correlated. The many-body results are close to the Gross-Pitaevskii results for a small number of bosons, however, large deviations are noted in the large particle limit. We also calculate the lowest collective excitation and the interaction energy for large scattering lengths. The monopole excitation frequency exhibits a pronounced dependence on the scattering length. We also observe a universal behavior for the interaction energy at the limit of large scattering length.

  8. Nonlinear Fundamental and Harmonic Cyclotron Resonant Scattering of Radiation Belt Ultra-Relativistic Electrons by Oblique Monochromatic EMIC Waves

    NASA Astrophysics Data System (ADS)

    Wang, G.; Su, Z.; Zheng, H.

    2016-12-01

    Cyclotron resonant scattering by electromagnetic ion cyclotron (EMIC) waves has been considered to be responsible for the rapid loss of radiation belt high-energy electrons. Recent studies have revealed the nonlinear character of cyclotron resonance with parallel-propagating EMIC waves. Here we investigate the fundamental and harmonic cyclotron resonance between radiation belt ultra-relativistic electrons and oblique monochromatic EMIC waves. We show that both fundamental and harmonic cyclotron resonance can exhibit significant nonlinearity for oblique EMIC waves. Higher wave obliquity allows stronger nonlinearity of harmonic resonance but weaker nonlinearity of fundamental resonance. The total transport coefficients of nonlinear resonances are found to deviate significantly from the quasi-linear predication. Increase of wave obliquity tends to reduce, to some extent, the difference between nonlinear and quasi-linear transport coefficients. These results suggest that the nonlinear resonant scattering even by oblique EMIC waves should be taken into account in future radiation belt modeling.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  10. Hemispherical transmittance determination of spectral radiative properties of the slab-like scattering specimen by moisture content variation

    NASA Astrophysics Data System (ADS)

    Švedas, V.

    2005-12-01

    The matter of the article is the transmission of radiation by the scattering and absorbing slab-shaped media. Spectral absorption and scattering coefficients (k,σ) have been determined from the hemispherical transmittance by minimizing the squared sum of differences E between the measured -logT and the calculated one according to equations of the developed model. The model starting point is the two-flux theory. Existence of analytical solutions for the two-flux transmittance allowed simple spectra treatment needed for inclusion of matrix algebra into E-minimization. Spectra of cellulose sheets were measured in the 1.30 2.19μm range with the varied content of adsorbed water in the range from 0 to 0.227. Set of 20 k,σ coefficients corresponding to 20 water content values, and separate spectral absorption coefficients of cellulose and water were the output of the spectral error minimization.

  11. Spectral property of two-photon flux generated by four-photon scattering in photonic-crystal fibers

    NASA Astrophysics Data System (ADS)

    Sun, Hongbo; Liu, Xueming; Hu, Xiaohong; Li, Xiaohui

    2010-12-01

    Based on the scalar four-photon scattering process, the quantum state of a lightwave at the output of fiber is derived by solving the nonlinear Schrödinger equation with a perturbation theory. The joint spectral function of two photons is achieved from the derived quantum state. The dispersion operator involves the third-order dispersion term in the case that the pump wavelength is close to the zero dispersion wavelength. Simulation results show the first-order approximation of our joint spectral function is in excellent agreement with the complicated exact solution. By analyzing the spectral property of the two-photon flux generated by four-photon scattering in photonic-crystal fibers, it is found that the sign of dispersion has very little influence on the spectrum except the slight modulation instability in the anomalous dispersion domain.

  12. Detecting non-bridging oxygens: non-resonant inelastic X-ray scattering in crystalline lithium borates.

    PubMed

    Lelong, Gérald; Radtke, Guillaume; Cormier, Laurent; Bricha, Hanane; Rueff, Jean-Pascal; Ablett, James M; Cabaret, Delphine; Gélébart, Frédéric; Shukla, Abhay

    2014-10-20

    Probing the local environment of low-Z elements, such as oxygen, is of great interest for understanding the atomic-scale behavior in materials, but it requires experimental techniques allowing it to work with versatile sample environments. In this paper, the local environment of lithium borate crystals is investigated using non-resonant inelastic X-ray scattering (NRIXS) at energy losses corresponding to the oxygen K-edge. Large variations of the spectral features are observed close to the edge onset in the 535-540 eV energy range when varying the Li2O content. Calculations allow identification of contributions associated with bridging oxygen (BO) and non-bridging oxygen (NBO) atoms. The main result resides in the observed core-level shift of about 1.7 eV in the spectral signatures of the BO and NBO. The clear signature at 535 eV in the O K-edge NRXIS spectrum is thus an original way to probe the presence of NBOs in borates, with the great advantage of making possible the use of complex environments such as a high-pressure cell or high-temperature device for in situ measurements.

  13. A novel curcumin assay with the metal ion Cu (II) as a simple probe by resonance light scattering technique

    NASA Astrophysics Data System (ADS)

    Chen, Zhanguang; Zhu, Li; Song, Tianhe; Chen, Junhui; Guo, Zhiming

    2009-04-01

    A fantastic resonance light scattering (RLS) enhancement phenomenon was found when the interaction between the metal ion Cu (II) and a natural antioxidant curcumin (C 21H 20O 6) occurred in certain conditions. Based on this phenomenon, a novel and convenient assay of curcumin was developed and successfully applied on the determination of curcumin in human urine samples. This assay applied the RLS technique with a common metal ion Cu (II) as the spectral probe. In the pH range of 6.5-7.5, the interaction between Cu (II) and curcumin occurred and the weak RLS intensity of Cu (II) was greatly enhanced by curcumin. The maximum peak was located at 538.5 nm. Under the optimum conditions, the enhanced RLS intensity was proportional to the concentration of curcumin ranging from 0.4 to 60 μg ml -1 with the detection limit of 0.07 μg ml -1. The synthetic and human urine samples were determined satisfactorily. Good recoveries (98.8-102.5%) were obtained in the determination of urine samples, which proved that the assay proposed was reliable and applicable in the determination of curcumin in body fluid. In this work, the RLS and fluorescence spectral characteristics of the chemicals, the optimum conditions of the reaction and the influencing factors were investigated.

  14. Absolute determination of cross sections for resonant Raman scattering on silicon

    NASA Astrophysics Data System (ADS)

    Müller, Matthias; Beckhoff, Burkhard; Ulm, Gerhard; Kanngießer, Birgit

    2006-07-01

    We studied the resonant Raman scattering of x rays in the vicinity of the K absorption edge of silicon. The investigation was carried out at the plane grating monochromator beamline for undulator radiation of the PTB laboratory at BESSY II in Berlin. Cross sections were determined absolutely for a wide energy range of incident photons with small relative uncertainties employing calibrated instrumentation avoiding any reference samples. The experimentally determined values differ clearly from the theoretical ones found in the literature.

  15. Resonant scattering as a sensitive diagnostic of current collisional plasma models

    NASA Astrophysics Data System (ADS)

    Ogorzalek, Anna; Zhuravleva, Irina; Allen, Steven W.; Pinto, Ciro; Werner, Norbert; Mantz, Adam; Canning, Rebecca; Fabian, Andrew C.; Kaastra, Jelle S.; de Plaa, Jelle

    2017-08-01

    Resonant scattering is a subtle process that suppresses fluxes of some of the brightest optically thick X-ray emission lines produced by collisional plasmas in galaxy clusters and massive early-type galaxies. The amplitude of the effect depends on the turbulent structure of the hot gas, making it a sensitive velocity probe. It is therefore crucial to properly model this effect in order to correctly interpret high resolution X-ray spectra. Our measurements of resonant scattering with XMM-Newton Reflection Grating Spectrometer in giant elliptical galaxies and with Hitomi in the center of Perseus Cluster show that the potentially rich inference from this effect is limited by the uncertainties in the atomic data underlying plasma codes such as APEC and SPEX. Typically, the effect is of the order of 10-20%, while the discrepancy between the two codes is of similar order or even higher. Precise knowledge of the emissivity and oscillator strengths of lines emitted by Fe XVII and Fe XXV, as well as their respective uncertainties propagated through plasma codes are key to understanding gas dynamics and microphysics in giant galaxies and cluster ICM, respectively. This is especially crucial for massive ellipticals, where sub-eV resolution would be needed to measure line broadening precisely, making resonant scattering an important velocity diagnostic in these systems for the foreseeable future. In this poster, I will summarize current status of resonant scattering measurements and show how they depend on the assumed atomic data. I will also discuss which improvements are essential to maximize scientific inference from future high resolution X-ray spectra.

  16. A Comparative Evaluation of Elasticity in Pentaerythritol tetranitrate using Brillouin Scattering and Resonant Ultrasound Spectroscopy

    SciTech Connect

    Stevens, L.; Hooks, D; Migliori, A

    2010-01-01

    Elastic tensors for organic molecular crystals vary significantly among different measurements. To understand better the origin of these differences, Brillouin scattering and resonant ultrasound spectroscopy measurements were made on the same specimen for single crystal pentaerythritol tetranitrate. The results differ significantly despite mitigation of sample-dependent contributions to errors. The frequency dependence and vibrational modes probed for both measurements are discussed in relation to the observed tensor variance.

  17. Resonant scattering of energetic electrons by unusual low-frequency hiss

    NASA Astrophysics Data System (ADS)

    Ni, Binbin; Li, Wen; Thorne, Richard M.; Bortnik, Jacob; Ma, Qianli; Chen, Lunjin; Kletzing, Craig A.; Kurth, William S.; Hospodarsky, George B.; Reeves, Geoffrey D.; Spence, Harlan E.; Bernard Blake, J.; Fennell, Joseph F.; Claudepierre, Seth G.

    2014-03-01

    We quantify the resonant scattering effects of the unusual low-frequency dawnside plasmaspheric hiss observed on 30 September 2012 by the Van Allen Probes. In contrast to normal (~100-2000 Hz) hiss emissions, this unusual hiss event contained most of its wave power at ~20-200 Hz. Compared to the scattering by normal hiss, the unusual hiss scattering speeds up the loss of ~50-200 keV electrons and produces more pronounced pancake distributions of ~50-100 keV electrons. It is demonstrated that such unusual low-frequency hiss, even with a duration of a couple of hours, plays a particularly important role in the decay and loss process of energetic electrons, resulting in shorter electron lifetimes for ~50-400 keV electrons than normal hiss, and should be carefully incorporated into global modeling of radiation belt electron dynamics during periods of intense injections.

  18. Compositeness of the Δ(1232) Resonance in πN Scattering

    NASA Astrophysics Data System (ADS)

    Sekihara, Takayasu; Arai, Takashi; Yamagata-Sekihara, Junko; Yasui, Shigehiro

    We evaluate the πN compositeness of the Δ(1232) resonance so as to clarify the internal structure of Δ(1232) in terms of the πN component. Here the compositeness is defined as contributions from two-body wave functions to the normalization of the total wave function and is extracted from the πN scattering amplitude. In this study we employ the chiral unitary approach with the interaction up to the next-to-leading order plus a bare Δ term in chiral perturbation theory and describe Δ(1232) in an elastic πN scattering. Fitting the πN scattering amplitude to the solution of the partial wave analysis, we obtain a large real part of the πN compositeness for Δ(1232) comparable to unity and non-negligible imaginary part as well, with which we reconfirm the result in the previous study on the πN compositeness for Δ(1232).

  19. Lattice model of resonant inelastic x-ray scattering in metals: relation of a strong core hole to the x-ray edge singularity.

    PubMed

    Markiewicz, R S; Rehr, J J; Bansil, A

    2014-06-13

    We show how the classic approach of Nozières and di Domenicis for treating the edge singularity in x-ray absorption and emission can be generalized to treat the more complex case of the resonant inelastic x-ray scattering (RIXS) process, including effects of the intermediate states involved therein in the presence of the core hole. We solve our lattice model essentially exactly (numerically) to obtain a novel form of edge singularity at the RIXS threshold energy. Our RIXS spectrum naturally includes both the well and poorly screened spectral components and their dispersions and allows its separation into pair and multiple-pair excitations.

  20. Directional Fano resonances in light scattering by a high refractive index dielectric sphere

    NASA Astrophysics Data System (ADS)

    Tribelsky, Michael I.; Geffrin, Jean-Michel; Litman, Amelie; Eyraud, Christelle; Moreno, Fernando

    2016-09-01

    We report the experimental evidence of directional Fano resonances at the scattering of a linearly polarized electromagnetic plane wave by a homogeneous dielectric sphere with a high refractive index and low losses. We observe a typical asymmetric Fano profile for the intensity scattered in practically any given direction, while the overall extinction cross section remains Lorentzian. The phenomenon originates in the interference of the selectively excited electric dipolar and quadrupolar modes. The selectivity of the excitation is achieved by the proper choice of the frequency of the incident wave. Owing to the scaling invariance of the Maxwell equations, in these experiments we mimic the scattering of the visible and near IR radiation by a nanoparticle made of common semiconductor materials (Si, Ge, GaAs, GaP) by the equivalent scattering of a spherical particle of 18 mm in diameter in the microwave range. The theory developed to explain the experiments extends the conventional Fano approach to the case when both interfering partitions are resonant. A perfect agreement between the experiment and the theory is demonstrated.

  1. Detuned surface plasmon resonance scattering of gold nanorods for continuous wave multilayered optical recording and readout.

    PubMed

    Taylor, Adam B; Kim, Jooho; Chon, James W M

    2012-02-27

    In a multilayered structure of absorptive optical recording media, continuous-wave laser operation is highly disadvantageous due to heavy beam extinction. For a gold nanorod based recording medium, the narrow surface plasmon resonance (SPR) profile of gold nanorods enables the variation of extinction through mulilayers by a simple detuning of the readout wavelength from the SPR peak. The level of signal extinction through the layers can then be greatly reduced, resulting more efficient readout at deeper layers. The scattering signal strength may be decreased at the detuned wavelength, but balancing these two factors results an optimal scattering peak wavelength that is specific to each layer. In this paper, we propose to use detuned SPR scattering from gold nanorods as a new mechanism for continuous-wave readout scheme on gold nanorod based multilayered optical storage. Using this detuned scattering method, readout using continuous-wave laser is demonstrated on a 16 layer optical recording medium doped with heavily distributed, randomly oriented gold nanorods. Compared to SPR on-resonant readout, this method reduced the required readout power more than one order of magnitude, with only 60 nm detuning from SPR peak. The proposed method will be highly beneficial to multilayered optical storage applications as well as applications using a continuous medium doped heavily with plasmonic nanoparticles.

  2. Scattering, resonance, creeping wave, traveling wave and all that: UWB measurements of various targets

    NASA Astrophysics Data System (ADS)

    Madonna, R. G.; Scheno, P. J.; Vilardi, G. H.; Hom, C.; Scannepieco, J.

    1993-01-01

    Ultra Wide Band (UWB) impulse radar has the potential to perform target identification. In order to realize this potential, target signatures must be measured and understood from the stand point of electromagnetic scattering. This paper discusses measurements of target 'echoes' using an impulse UWB system. We first examine the interaction of the transmitted pulse with conductive plates. At small incidence angles, we observe both specular scattering and a late time resonance. At large incidence angles, interactions with the leading edge and traveling waves are observed. In order to enhance the traveling wave interaction, we fabricated and test 'bullets' which are 5 foot long, 6 inch wide aluminum strips whose front ends are tapered to a point. The bullets are oriented approximately 20 deg to the incident wave. The returns from the bullets are due almost completely to traveling wave. We then look at data gather from a sphere. One clearly sees the specular return followed by the creeping wave. Resonance is observed at late times. We also have examined a dipole, which has a very large cross section at its resonance frequency. The dipole clearly exhibits ringing at ist fundamental fequency. We have fabricated and are in the process of measuring a resonance cavity. The cavity consists of a 27 inch diameter sphere with a 20 deg cap removed and a conducting cone (13.5 inches high) inserted into the sphere. We are observing resonance, and scattering from the cone. We will have more details to report at a later time as the measurements are in progress.

  3. Carotid Plaque Evaluation Using Gemstone Spectral Imaging: Comparison with Magnetic Resonance Angiography.

    PubMed

    Shinohara, Yuki; Sakamoto, Makoto; Kuya, Keita; Kishimoto, Junichi; Yamashita, Eijiro; Fujii, Shinya; Kurosaki, Masamichi; Ogawa, Toshihide

    2017-07-01

    The present study compared the applicability of computed tomography carotid plaque imaging using effective Z maps with gemstone spectral imaging (GSI) to that of magnetic resonance plaque imaging using 3-dimensional time-of-flight magnetic resonance angiography. Stenosis was assessed in 18 carotid arteries of 14 patients, and the effective Z values of noncalcified carotid plaques were compared with the signal intensities of magnetic resonance angiography. It was found that the effective Z value of noncalcified carotid plaques was significantly lower for a group with high signal intensity than for a group with low signal intensity on magnetic resonance angiography (P <.001). The area under the receiver operating characteristic curve of effective Z values was .975, and the presumed cutoff effective Z value required to discriminate low and high intensity plaques on magnetic resonance angiography was 7.83. The effective Z value generated by GSI is a useful parameter to detect vulnerable carotid plaque materials. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  4. Double-way spectral tunability for the control of optical nanocavity resonance

    NASA Astrophysics Data System (ADS)

    Baida, Fadi I.; Grosjean, Thierry

    2015-12-01

    Scanning Near-field Optical Microscopy (SNOM) has been successful in finely tuning the optical properties of photonic crystal (PC) nanocavities. The SNOM nanoprobes proposed so far allowed for either redshifting or blueshifting the resonance peak of the PC structures. In this paper, we theoretically demonstrate the possibility of a redshifting (up to +0.65 nm) and a blueshifting (up to -5 nm) the PC cavity resonance wavelength with a single perturbation element. As an example, a fiber bowtie-aperture nano-antenna (BNA) engraved at the apex of a SNOM tip is proposed to play this role. The double-way tunability is the result of a competition between an induced electric dipole (BNA at resonance) leading to a redshift and an induced magnetic dipole (the tip metalcoating) giving rise to a blueshift of the resonance wavelength. We demonstrate that the sign of the spectral shift can be simply controlled through the tip-to-cavity distance. This study opens the way to the full postproduction control of the resonance wavelength of high quality-factor optical cavities.

  5. Double-way spectral tunability for the control of optical nanocavity resonance.

    PubMed

    Baida, Fadi I; Grosjean, Thierry

    2015-12-08

    Scanning Near-field Optical Microscopy (SNOM) has been successful in finely tuning the optical properties of photonic crystal (PC) nanocavities. The SNOM nanoprobes proposed so far allowed for either redshifting or blueshifting the resonance peak of the PC structures. In this paper, we theoretically demonstrate the possibility of a redshifting (up to +0.65 nm) and a blueshifting (up to -5 nm) the PC cavity resonance wavelength with a single perturbation element. As an example, a fiber bowtie-aperture nano-antenna (BNA) engraved at the apex of a SNOM tip is proposed to play this role. The double-way tunability is the result of a competition between an induced electric dipole (BNA at resonance) leading to a redshift and an induced magnetic dipole (the tip metalcoating) giving rise to a blueshift of the resonance wavelength. We demonstrate that the sign of the spectral shift can be simply controlled through the tip-to-cavity distance. This study opens the way to the full postproduction control of the resonance wavelength of high quality-factor optical cavities.

  6. Observation of forbidden phonons, Fano resonance and dark excitons by resonance Raman scattering in few-layer WS2

    NASA Astrophysics Data System (ADS)

    Tan, Qing-Hai; Sun, Yu-Jia; Liu, Xue-Lu; Zhao, Yanyuan; Xiong, Qihua; Tan, Ping-Heng; Zhang, Jun

    2017-09-01

    The optical properties of the two-dimensional (2D) crystals are dominated by tightly bound electron-hole pairs (excitons) and lattice vibration modes (phonons). The exciton-phonon interaction is fundamentally important to understand the optical properties of 2D materials and thus helps to develop emerging 2D crystal based optoelectronic devices. Here, we presented the excitonic resonant Raman scattering (RRS) spectra of few-layer WS2 excited by 11 lasers lines covered all of A, B and C exciton transition energies at different sample temperatures from 4 to 300 K. As a result, we are not only able to probe the forbidden phonon modes unobserved in ordinary Raman scattering, but also can determine the bright and dark state fine structures of 1s A exciton. In particular, we also observed the quantum interference between low-energy discrete phonon and exciton continuum under resonant excitation. Our works pave a way to understand the exciton-phonon coupling and many-body effects in 2D materials.

  7. Surface-enhanced Raman scattering on silvered porous alumina templates: role of multipolar surface plasmon resonant modes.

    PubMed

    Terekhov, S N; Kachan, S M; Panarin, A Yu; Mojzes, P

    2015-12-21

    Nanostructured silver films with different thicknesses were prepared by vapor deposition onto the surface of the anodic aluminum oxide (AAO) template to be used as surface-enhanced Raman scattering (SERS) active substrates. Both the peak position of the surface plasmon resonance (SPR) band and SERS enhancement of silvered AAO samples displayed non-monotonous dependence on Ag layer thickness. Using 441.6 nm excitation and a water-soluble cationic porphyrin, Cu(ii)-tetrakis(4-N-methylpyridyl) (CuTMPyP4), as a SERS-reporting analyte, two maxima of the SERS enhancement were obtained for Ag layers of 15 and 120 nm thickness. Thickness dependencies have been analyzed taking into account the type of SPR modes identified by means of quasicrystalline approximation (QCA) of statistical theory of multiple scattering of waves and multi-Lorentzian deconvolution. The analysis revealed that SERS enhancement is related to the absolute magnitude of the distance between excitation wavelength and spectral position of collective SPR mode. It was shown that matching of excitation wavelength and the most intensive SPR modes with non-radiative decay, generated mainly by coherent interaction of higher-order plasmon resonant modes (quadrupole and octupole), plays a dominate role in SERS performance. Besides, it has been observed that more intense SERS signal can be obtained when the analyte deposited on the Ag/AAO substrate was excited through the AAO template rather than from the silvered side. Our results demonstrate that appropriate excitation geometry and fine-tuning of the optical properties of the Ag/AAO substrate by adjusting the thickness of the Ag layer with respect to particular excitation wavelength can contribute to more effective SERS enhancement.

  8. Dynamical rate theory of enzymatic reactions and triple-resonant coherent anti-Stokes Raman scattering microspectroscopy

    NASA Astrophysics Data System (ADS)

    Min, Wei

    combines the advantages of both coherent Raman scattering and electronic resonant Raman scattering within an optical microscopy, through the latest pulse shaping technology. We demonstrate the applicability of this technique on various different systems, including genetically encoded chromoproteins, and show that the current sensitivity is approaching 50 non-fluorescent molecules in aqueous solution with possible Raman spectral identification, thus boosting the sensitivity of the current CARS microscopy by 103 to 10 5 folds.

  9. Lower hybrid wave resonance cone detection via CO/sub 2/ laser scattering

    SciTech Connect

    Wurden, G.A.; Wong, K.L.; Ono, M.

    1984-04-01

    Lower hybrid waves are studied in the Princeton ACT-I steady-state toroidal plasma device using a radially scanning CO/sub 2/ laser scattering system with both amplitude and phase sensitive detection techniques. Clearly defined resonance cones launched from external electrostatic antennas are seen to disappear as the plasma density is raised. Scaling of LHW laser signal with RF power in the presence of resonance cones shows nonlinearities associated with RF induced changes in the effective laser scattering volume. Absolute fluctuation level estimates suggest this occurs when e PHI/T/sub e/ greater than or equal to 1. Wavefront curvature effects can cause a complete loss of resonance cone laser signals, even though probes indicate that cones are still present. Measurements of the wave k/sub perpendicular/-spectrum in the plasma show direct evidence for electron Landau filtering of the original wave k/sub parallel/-spectrum launched from the antenna at the plasma edge, and strong dependence on antenna phasing. Finally, frequency shifts and loss of the resonance cone signal are associated with high levels of plasma density edge turbulence.

  10. Directly probing anisotropy in atom-molecule collisions through quantum scattering resonances

    NASA Astrophysics Data System (ADS)

    Klein, Ayelet; Shagam, Yuval; Skomorowski, Wojciech; Żuchowski, Piotr S.; Pawlak, Mariusz; Janssen, Liesbeth M. C.; Moiseyev, Nimrod; van de Meerakker, Sebastiaan Y. T.; van der Avoird, Ad; Koch, Christiane P.; Narevicius, Edvardas

    2017-01-01

    Anisotropy is a fundamental property of particle interactions. It occupies a central role in cold and ultracold molecular processes, where orientation-dependent long-range forces have been studied in ultracold polar molecule collisions. In the cold collisions regime, quantization of the intermolecular degrees of freedom leads to quantum scattering resonances. Although these states have been shown to be sensitive to details of the interaction potential, the effect of anisotropy on quantum resonances has so far eluded experimental observation. Here, we directly measure the anisotropy in atom-molecule interactions via quantum resonances by changing the quantum state of the internal molecular rotor. We observe that a quantum scattering resonance at a collision energy of kB × 270 mK appears in the Penning ionization of molecular hydrogen with metastable helium only if the molecule is rotationally excited. We use state-of-the-art ab initio theory to show that control over the rotational state effectively switches the anisotropy on or off, disentangling the isotropic and anisotropic parts of the interaction.

  11. Signal enhancement of surface enhanced Raman scattering and surface enhanced resonance Raman scattering using in situ colloidal synthesis in microfluidics.

    PubMed

    Wilson, Rab; Bowden, Stephen A; Parnell, John; Cooper, Jonathan M

    2010-03-01

    We demonstrate the enhanced analytical sensitivity of both surface enhanced Raman scattering (SERS) and surface enhanced resonance Raman scattering (SERRS) responses, resulting from the in situ synthesis of silver colloid in a microfluidic flow structure, where both mixing and optical interrogation were integrated on-chip. The chip-based sensor was characterized with a model Raman active label, rhodamine-6G (R6G), and had a limit of detection (LOD) of ca. 50 fM (equivalent to single molecule detection). The device was also used for the determination of the natural pigment, scytonemin, from cyanobacteria (as an analogue for extraterrestrial life existing in extreme environments). The observed LOD of approximately 10 pM (ca. <400 molecules) demonstrated the analytical advantages of working with freshly synthesized colloid in such a flow system. In both cases, sensitivities were between 1 and 2 orders of magnitude greater in the microfluidic system than those measured using the same experimental parameters, with colloid synthesized off-chip, under quiescent conditions.

  12. Switching of transmission resonances in a two-channels coupler: A Boundary Wall Method scattering study

    SciTech Connect

    Nunes, A.; Zanetti, F.M.; Lyra, M.L.

    2016-10-15

    In this work, we study the transmission characteristics of a two-channels coupler model system using the Boundary Wall Method (BWM) to determine the solution of the corresponding scattering problem of an incident plane wave. We show that the BWM provides detailed information regarding the transmission resonances. In particular, we focus on the case of single channel input aiming to explore the energy switching performance of the coupler. We show that the coupler geometry can be tailored to allow for the first transmission resonances to be predominantly transmitted on specific output channels, an important characteristic for the realization of logical operations. - Highlights: • The switching performance of a coupled waveguide device is studied via the boundary wall method. • The method efficiently identifies all resonant transmission modes. • Energy switching is controlled and optimized as a function of the device geometry.

  13. Demonstration of highly efficient forward stimulated Brillouin scattering in partly suspended silicon nanowire racetrack resonators

    NASA Astrophysics Data System (ADS)

    Zhang, Ruiwen; Sun, Junqiang; Chen, Guodong; Cheng, Ming; Jiang, Jialin

    2017-07-01

    We demonstrate the forward stimulated Brillouin scattering (FSBS) in a partly suspended silicon nanowire racetrack resonator. To realize the tight confinement of the transverse acoustic modes in the nanoscale silicon core, the racetrack resonator is supported by the tiny pillar. The Brillouin amplification of 2.25 dB is achieved with the resonator radius of 100 μm under a low-power pump laser of 8 mW. The influences of the waveguide width and the top width of the tiny pillar on the Brillouin frequency shift and Brillouin gain are presented and analyzed. The Brillouin frequency shift is conveniently manipulated by the changes in waveguide widths. Our proposed approach furnishes an alternative towards harnessing FSBS in integrated photonic circuits.

  14. Interplay of resonant and Auger processes in proton neutralization after grazing surface scattering

    NASA Astrophysics Data System (ADS)

    Zimny, R.; Mišković, Z. L.; Nedeljković, N. N.; Nedeljković, Lj. D.

    1991-09-01

    We present model calculations for proton neutralization after grazing reflection at an aluminum surface over a wide range of projectile velocities around the Bohr or Fermi velocity. The contribution of excited hydrogen states to the neutral fraction, as well as negative-ion formation can be regarded as small in this case. Both resonant and Auger electron capture from the metallic conduction band into the 1s ground state of hydrogen as well as electron loss by resonance and Auger ionization of the ground state are taken into account on equal footing within a rate-equation approach. As a consequence, our model allows to estimate, for the first time, the effect of the particle velocity parallel to the surface plane on the relative role of resonant and Auger-type electron transfer in ion-surface neutralization. The results of our theoretical model are compared with recent experimental data for grazing scattering of protons at an Al(111) surface.

  15. Spectral Resolution of the Neumann-Poincaré Operator on Intersecting Disks and Analysis of Plasmon Resonance

    NASA Astrophysics Data System (ADS)

    Kang, Hyeonbae; Lim, Mikyoung; Yu, Sanghyeon

    2017-10-01

    The purpose of this paper is to investigate the spectral nature of the Neumann-Poincaré operator on the intersecting disks, which is a domain with the Lipschitz boundary. The complete spectral resolution of the operator is derived, which shows, in particular, that it admits only the absolutely continuous spectrum; no singularly continuous spectrum and no pure point spectrum. We then quantitatively analyze using the spectral resolution of the plasmon resonance at the absolutely continuous spectrum.

  16. Ordinary and supernumerary resonant scattering of low energy electrons from the BiCu2(111) surface alloy

    NASA Astrophysics Data System (ADS)

    Poelsema, Bene; Altman, Michael S.; van Gastel, Raoul; Zandvliet, Harold J. W.; van Houselt, Arie

    2017-01-01

    Electron intensity versus energy curves from the ordered substitutional BiCu2(111)-surface alloy, obtained with low energy electron microscopy (LEEM), show distinct unexpected intensity dips under normal incidence conditions. The dips above 10 eV are found to be characteristic of ordinary resonant scattering of electrons. Their positions represent resonant scattering into image potential states, involving scattering along G 10 and G 11 reciprocal lattice vectors. A detailed analysis of additional specular intensity dips at energies below 10 eV demonstrates that these originate from supernumerary resonant scattering, now also along lower symmetry directions, that should be forbidden in this energy range for the perfect crystal. LEEM is highly sensitive to detect these often neglected features which, if not properly disentangled or discarded, hamper its potential to extract the rich information about atomic positions and unoccupied electronic states encoded in very low energy electron scattering.

  17. Collective scattering in hybrid nanostructures with many atomic oscillators coupled to an electromagnetic resonance

    NASA Astrophysics Data System (ADS)

    Fauché, Pierre; Kosionis, Spyridon G.; Lalanne, Philippe

    2017-05-01

    There is considerable interest in collective effects in hybrid systems formed by molecular or atomic ensembles strongly coupled by an electromagnetic resonance. For analyzing such collective effects, we develop an efficient and general theoretical formalism based on the natural modes of the resonator. The main strength of our approach is its generality and the high level of analyticity enabled by modal analysis, which allows one to model complex hybrid systems without any restriction on the resonator shapes or material properties, and to perform statistical computations to predict general properties that are robust to spatial and polarization disorders. Most notably, we establish that super-radiant modes remain even after ensemble averaging and act as an "invisibility cloak" with a spectral bandwidth that scales with the number of oscillators and the spatially averaged Purcell factor.

  18. The role of planar symmetry and scattering-enhanced tunneling in resonant transport

    NASA Astrophysics Data System (ADS)

    Russell, Kasey Joe

    Although there has been active research on resonant transport in planar semiconductor structures for more than 30 years, there still is no general framework for understanding when resonant transport will dominate a structure. Here we present the development of such a framework. Our technique is based on capacitance-voltage spectroscopy, and it allows us to directly determine whether the transport is dominated by resonant, momentum-conserved tunneling or scattering-enhanced tunneling. We measure the timeconstant associated with tunneling in and out of a given 2D system, and we relate this timeconstant to the quasi-bound state lifetime. The key feature of our method is the ability to measure the lifetime while varying the energy of the quasi-bound state. This is achieved by applying a DC bias to the sample and varying the carrier concentration of the two-dimensional electron gas. The response of the lifetime to changes in DC bias indicates which transport mechanism dominates in a given device. By measuring the transport characteristics of several different sample structures, we are able to determine which structures are more or less sensitive to disrupted planar symmetry and scattering-enhanced tunneling. Within certain sample structures, the dominant transport mechanism can switch from resonant tunneling to scattering-enhanced tunneling. One way to cause this change is by varying the carrier concentration within the two-dimensional electron gas. A less obvious way is to apply a magnetic field perpendicular to the layers. Increasing the magnetic field sweeps the chemical potential alternately through the cyclotron orbitals of Landau Levels and the edge states that surround defects. As the chemical potential crosses a Landau Level, the quasi-bound state lifetime jumps by nearly two orders of magnitude. This, we suggest, is a planar-tunneling analogue of the Integer Quantum Hall effect. After identifying the relevant sample parameters, a simple scaling allows us to map

  19. Spectrally-broad coherent anti-Stokes Raman scattering hyper-microscopy utilizing a Stokes supercontinuum pumped at 800 nm.

    PubMed

    Porquez, Jeremy G; Cole, Ryan A; Tabarangao, Joel T; Slepkov, Aaron D

    2016-10-01

    We demonstrate spectral-focusing based coherent anti-Stokes Raman scattering (SF-CARS) hyper-microscopy capable of probing vibrational frequencies from 630 cm(-1) to 3250 cm(-1) using a single Ti:Sapphire femtosecond laser operating at 800 nm, and a commercially-available supercontinuum-generating fibre module. A broad Stokes supercontinuum with significant spectral power at wavelengths between 800 nm and 940 nm is generated by power tuning the fibre module using atypically long and/or chirped ~200 fs pump pulses, allowing convenient access to lower vibrational frequencies in the fingerprint spectral region. This work significantly reduces the instrumental and technical requirements for multimodal CARS microscopy, while expanding the spectral capabilities of an established approach to SF-CARS.

  20. Spectrally-broad coherent anti-Stokes Raman scattering hyper-microscopy utilizing a Stokes supercontinuum pumped at 800 nm

    PubMed Central

    Porquez, Jeremy G.; Cole, Ryan A.; Tabarangao, Joel T.; Slepkov, Aaron D.

    2016-01-01

    We demonstrate spectral-focusing based coherent anti-Stokes Raman scattering (SF-CARS) hyper-microscopy capable of probing vibrational frequencies from 630 cm−1 to 3250 cm−1 using a single Ti:Sapphire femtosecond laser operating at 800 nm, and a commercially-available supercontinuum-generating fibre module. A broad Stokes supercontinuum with significant spectral power at wavelengths between 800 nm and 940 nm is generated by power tuning the fibre module using atypically long and/or chirped ~200 fs pump pulses, allowing convenient access to lower vibrational frequencies in the fingerprint spectral region. This work significantly reduces the instrumental and technical requirements for multimodal CARS microscopy, while expanding the spectral capabilities of an established approach to SF-CARS. PMID:27867735

  1. RESONANT X-RAY SCATTERING AS A PROBE OF ORBITAL AND CHARGE ORDERING.

    SciTech Connect

    NELSON,C.S.; HILL,J.P.; GIBBS,D.

    2002-05-13

    Resonant x-ray scattering is a powerful experimental technique for probing orbital and charge ordering. It involves tuning the incident photon energy to an absorption edge of the relevant ion and observing scattering at previously ''forbidden'' Bragg peaks, and it allows high-resolution, quantitative studies of orbital and charge order--even from small samples. Further, resonant x-ray scattering from orbitally ordered systems exhibits polarization- and azimuthal-dependent properties that provide additional information about the details of the orbital order that is difficult, or impossible, to obtain with any other technique. In the manganites, the sensitivity to charge and orbital ordering is enhanced when the incident photon energy is tuned near the Mn K absorption edge (6.539 keV), which is the lowest energy at which a 1s electron can be excited into an unoccupied state. In this process, the core electron is promoted to an intermediate excited state, which decays with the emission of a photon. The sensitivity to charge ordering is believed to be due to the small difference in K absorption edges of the Mn{sup 3+} and Mn{sup 4+} sites. For orbital ordering, the sensitivity arises from a splitting--or difference in the weight of the density of states [239]--of the orbitals occupied by the excited electron in the intermediate state. In the absence of such a splitting, there is no resonant enhancement of the scattering intensity. In principle, other absorption edges in which the intermediate state is anisotropic could be utilized, but the strong dipole transition to the Mn 4p levels--and their convenient energies for x-ray diffraction--make the K edge well-suited to studies of manganites. The Mn 4p levels are affected by the symmetry of the orbital ordering, which makes the technique sensitive to the orbital degree of freedom. Therefore resonant x-ray scattering can be used to obtain important quantitative information concerning the details of this electronic order

  2. Detection of possible cyclotron resonance scattering feature in the accretion powered X-ray pulsar 4U 1909+07

    NASA Astrophysics Data System (ADS)

    Jaisawal, Gaurava K.; Naik, Sachindra; Paul, Biswajit

    We present the timing and spectral analysis of high mass X-ray binary pulsar 4U 1909+07 using data from the Suzaku observation on 2 November 2010. The pulse period of pulsar is estimated to be 604.058(1) s. Pulsations are seen in the X-ray light curves up to ˜40 keV. The energy resolved pulse profiles are found to be strongly energy dependent. Presence of several absorption features at various pulse phases, below 10 keV make the soft X-ray pulse profiles complex. At high energies, however, the pulse profiles are found to be single peaked. We tried to fit the 1-100 keV phase averaged spectrum of the pulsar with various continuum models such as partial covering high energy cut-off power-law, cut-off power-law, negative and positive power-law times exponential cutoff (NPEX) etc. However, we found that the partial covering power-law with black-body component at soft X-rays fitted the data better. A weak iron fluorescence emission line is detected in the spectrum. The presence of an absorption like feature at ˜43 keV in the residue of the spectral fitting allowed us to add a cyclotron scattering resonance feature (CSRF) at above energy that improved the spectral fitting further. To check the presence of CSRF in the spectrum, we normalized the pulsar spectrum with respect to that of the Crab Nebula. The Crab spectrum is a featureless power-law with a photon index of ˜2.1. The resulting ``Crab ratio'' showed a clear dip like feature centered at ˜43 keV which we identified as CRSF in the pulsar. We estimated the surface magnetic field of the pulsar to be 3.7 × 10^{12} Gauss.

  3. Large area conductive nanoaperture arrays with strong optical resonances and spectrally flat terahertz transmission

    NASA Astrophysics Data System (ADS)

    Krewer, K. L.; Jiang, K.; Bley, K.; Jin, Z.; Mics, Z.; Weiss, C. K.; Landfester, K.; Elmers, H.-J.; Bonn, M.; Turchinovich, D.

    2017-07-01

    Using simple and inexpensive nanosphere lithography, we produce large, centimeter-squared sized thin golden films patterned with a hexagonal array of nanoapertures with controllable dimensions on the order of 100-300 nm, spaced by a 350-375 nm pitch distance. The optical transmission spectra of our samples are dominated by the resonant plasmonic features in the spectral range 500-700 nm, caused by the nanostructure in the film. At the same time, the transmission at terahertz (THz) radiation is as high as ˜10% and is spectrally flat. Our measurements are in agreement with finite difference time domain simulations. Such thin metal hole array films allow for very efficient injection of optical energy, while at the same time maintaining reasonably high transparency of THz waves. These structures can be used in any application combining strong optical sensitivity and THz transparency, in optical biomolecular sensing, or as optically transparent electrodes.

  4. IR spectral density of weak H-bonded complexes involving damped Fermi resonances. I. Quantum theory

    NASA Astrophysics Data System (ADS)

    Henri-Rousseau, Olivier; Chamma, Didier

    1998-03-01

    The IR spectral density of the high frequency stretching mode of weak H-bonded complexes involving Fermi resonances is studied within the linear response theory from a full quantum mechanical point of view: the anharmonic coupling between the high frequency X-H and the low frequency X-H⋯Y modes is treated inside the strong anharmonic coupling theory. Following Witkowski and Wójcik [A. Witkowski, M. Wójcik, Chem. Phys. 1 (1973) 9.], the Fermi resonance between the first excited state of the fast mode and the first harmonic of single or several bending modes is introduced. Besides, the direct relaxation involved by the fast and bending modes are incorporated, in the spirit of the reduced Green formalism, by aid of imaginary damping terms. The spectral density is obtained by the Fourier transform of the autocorrelation function of the dipole moment operator of the fast mode, in which time dependent terms appear that are solution of a set of coupled linear differential equations. It reduces in the special situation where the Fermi coupling is ignored to that obtained by Rösch and Ratner [N. Rösch, M. Ratner, J. Chem. Phys. 61 (1974) 3344.]. Furthermore, when the anharmonic coupling between the slow and fast modes is neglected, it reduces to the spectral density that may be obtained in the framework of the Giry et al. [M. Giry, B. Boulil, O. Henri-Rousseau, C.R. Acad. Sci. Paris 316 s.II (1993) 455; B. Boulil, M. Giry, O. Henri-Rousseau, Phys. status solidi (b) 158 (1990) 629.] approach. At last, it reduces to the Witkowski and Wójcik [A. Witkowski, M. Wójcik, Chem. Phys. 1 (1973) 9.] approach, when the relaxation disappears. A generalization to several Fermi resonances is also proposed. Numerical tests of the theory and physical discussions are reported in the following paper [D. Chamma, O. Henri-Rousseau, Chem. Phys. 229 (1998) 51].

  5. Electronic-resonance-enhanced coherent anti-Stokes Raman scattering of nitric oxide: Saturation and Stark effects

    NASA Astrophysics Data System (ADS)

    Chai, Ning; Lucht, Robert P.; Kulatilaka, Waruna D.; Roy, Sukesh; Gord, James R.

    2010-08-01

    A theoretical analysis of electronic-resonance-enhanced (ERE) coherent anti-Stokes Raman scattering (CARS) of NO is described. The time-dependent density-matrix equations for the nonlinear ERE-CARS process are derived and manipulated into a form suitable for direct numerical integration. In the ERE-CARS configuration considered in this paper, the pump and Stokes beams are far from electronic-resonance. The visible 532 and 591 nm laser beams are used to excite Q-branch Raman resonances in the vibrational bands of the X Π2 electronic state of NO. An ultraviolet probe beam at 236 nm is used to excite P-, Q-, or R-branch transitions in the (v '=0, v″=1) band of the A Σ2+-X Π2 electronic system of NO molecule. Experimental spectra are obtained either by scanning the ultraviolet probe beam while keeping the Stokes frequency fixed (probe scans) or by scanning the Stokes frequency while keeping the probe frequency fixed (Stokes scans). The calculated NO ERE-CARS spectra are compared with experimental spectra, and good agreement is observed between theory and experiment in terms of spectral peak locations and relative intensities. The effects of saturation of the two-photon Raman-resonant Q-branch transitions, the saturation of a one-photon electronic-resonant P-, Q-, or R-branch transitions in the A Σ2+-X Π2 electronic system, and the coupling of these saturation processes are investigated. The coupling of the saturation processes for the probe and Raman transitions is complex and exhibits behavior similar to that observed in the electromagnetic induced transparency process. The probe scan spectra are significantly affected by Stark broadening due to the interaction of the pump and Stokes radiation with single-photon resonances between the upper vibration-rotation probe level in the A Σ2+ electronic levels and vibration-rotation levels in higher lying electronic levels. The ERE-CARS signal intensity is found to be much less sensitive to variations in the

  6. Period Ratio Distribution of Near-Resonant Planets Indicates Planetesimal Scattering

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sourav; Krantzler, Seth O.; Ford, Eric B.

    2016-10-01

    An intriguing trend among it Kepler's multi-planet systems is an overabundance of planet pairs with period ratios just wide of mean motion resonances (MMR) and a dearth of systems just narrow of them. In a recently published paper Chatterjee & Ford (2015; henceforth CF15) has proposed that gas-disk migration traps planets in a MMR. After gas dispersal, orbits of these trapped planets are altered through interaction with a residual planetesimal disk. They found that for massive enough disks planet-planetesimal disk interactions can break resonances and naturally create moderate to large positive offsets from the initial period ratio for large ranges of planetesimal disk and planet properties. Divergence from resonance only happens if the mass of planetesimals that interact with the planets is at least a few percent of the total planet mass. This threshold, above which resonances are broken and the offset from resonances can grow, naturally explains why the asymmetric large offsets were not seen in more massive planet pairs found via past radial velocity surveys. In this article we will highlight some of the key findings of CF15. In addition, we report preliminary results from an extension of this study, that investigates the effects of planet-planetesimal disk interactions on initially non-resonant planet pairs. We find that planetesimal scattering typically increases period ratios of non-resonant planets. If the initial period ratios are below and in proximity of a resonance, under certain conditions, this increment in period ratios can create a deficit of systems with period ratios just below the exact integer corresponding to the MMR and an excess just above. From an initially uniform distribution of period ratios just below a 2:1 MMR, planetesimal interactions can create an asymmetric distribution across this MMR similar to what is observed for the kepler planet pairs.

  7. Spectral engineering by flexible tunings of optical Tamm states and Fabry-Perot cavity resonance.

    PubMed

    Zhang, Xu-Lin; Song, Jun-Feng; Feng, Jing; Sun, Hong-Bo

    2013-11-01

    We present a design for spectral engineering in a metal dual distributed Bragg reflector (DBR)-based structure. Optical Tamm states and Fabry-Perot cavity mode, dual windows for light-matter interaction enhancement, can be excited simultaneously and tuned flexibly, including their respective bandwidth and resonant wavelength, due to the variable reflection phase from the outer DBR's internal surface. The design can find applications in solar cells for light trappings. Via calculations of overall absorptivity, the proposed simpler dual-states-based scheme is demonstrated to be almost as effective as the coherent-light-trapping scheme, owing to the dual-states-induced broader-band absorption enhancement.

  8. Compound faults detection in gearbox via meshing resonance and spectral kurtosis methods

    NASA Astrophysics Data System (ADS)

    Wang, Tianyang; Chu, Fulei; Han, Qinkai; Kong, Yun

    2017-03-01

    Kurtosis-based impulsive component identification is one of the most effective algorithms in detecting localized faults in both gearboxes and rolling bearings. However, if localized faults exist in both gear tooth and rolling bearing simultaneously it is difficult to tell the differences between the two types of defects. As such, this study proposes a new method to solve the problem by using the meshing resonance and spectral kurtosis (SK) algorithms together. In specific, the raw signal is first decomposed into different frequency bands and levels, and then the corresponding Kurtogram and MRgram are calculated via the fault SK analysis and the meshing index. Furthermore, the resonance frequency bands induced by localized faults of the gear tooth and rolling bearing are separately identified by comparing the Kurtogram and the MRgram. Finally, the compound faults are respectively detected using envelope analysis. The effectiveness of the proposed method has been validated via both simulated and experimental gearboxes vibration signals with compound faults.

  9. Circuit model optimization of a nano split ring resonator dimer antenna operating in infrared spectral range

    SciTech Connect

    Gneiding, N.; Zhuromskyy, O.; Peschel, U.; Shamonina, E.

    2014-10-28

    Metamaterials are comprised of metallic structures with a strong response to incident electromagnetic radiation, like, for example, split ring resonators. The interaction of resonator ensembles with electromagnetic waves can be simulated with finite difference or finite elements algorithms, however, above a certain ensemble size simulations become inadmissibly time or memory consuming. Alternatively a circuit description of metamaterials, a well developed modelling tool at radio and microwave frequencies, allows to significantly increase the simulated ensemble size. This approach can be extended to the IR spectral range with an appropriate set of circuit element parameters accounting for physical effects such as electron inertia and finite conductivity. The model is verified by comparing the coupling coefficients with the ones obtained from the full wave numerical simulations, and used to optimize the nano-antenna design with improved radiation characteristics.

  10. Nitric oxide concentration measurements in atmospheric pressure flames using electronic-resonance-enhanced coherent anti-Stokes Raman scattering

    NASA Astrophysics Data System (ADS)

    Chai, N.; Kulatilaka, W. D.; Naik, S. V.; Laurendeau, N. M.; Lucht, R. P.; Kuehner, J. P.; Roy, S.; Katta, V. R.; Gord, J. R.

    2007-06-01

    We report the application of electronic-resonance-enhanced coherent anti-Stokes Raman scattering (ERE-CARS) for measurements of nitric oxide concentration ([NO]) in three different atmospheric pressure flames. Visible pump (532 nm) and Stokes (591 nm) beams are used to probe the Q-branch of the Raman transition. A significant resonance enhancement is obtained by tuning an ultraviolet probe beam (236 nm) into resonance with specific rotational transitions in the (v’=0, v”=1) vibrational band of the A2Σ+-X2Π electronic system of NO. ERE-CARS spectra are recorded at various heights within a hydrogen-air flame producing relatively low concentrations of NO over a Hencken burner. Good agreement is obtained between NO ERE-CARS measurements and the results of flame computations using UNICORN, a two-dimensional flame code. Excellent agreement between measured and calculated NO spectra is also obtained when using a modified version of the Sandia CARSFT code for heavily sooting acetylene-air flames (φ=0.8 to φ=1.6) on the same Hencken burner. Finally, NO concentration profiles are measured using ERE-CARS in a laminar, counter-flow, non-premixed hydrogen-air flame. Spectral scans are recorded by probing the Q1 (9.5), Q1 (13.5) and Q1 (17.5) Raman transitions. The measured shape of the [NO] profile is in good agreement with that predicted using the OPPDIF code, even without correcting for collisional effects. These comparisons between [NO] measurements and predictions establish the utility of ERE-CARS for detection of NO in flames with large temperature and concentration gradients as well as in sooting environments.

  11. Bound and scattering properties in waveguides around free-space Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Wang, Gaoren; Giannakeas, Panogiotis; Schmelcher, Peter

    2016-05-01

    The two-body bound and scattering properties in an one-dimensional (1D) harmonic waveguide in the vicinity of free-space magnetic Feshbach resonances are investigated based on the local frame transformation approach. The multichannel characteristics of the interatomic interaction is taken into account. We examine the crossing between the bound state in the waveguide and the ground level of the transverse confinement, i.e. when the bound state crosses the scattering threshold in the waveguide and turns into a continuum state. For s-wave collision, the crossing occurs at the magnetic field where the effective 1D interaction strength g1 D vanishes, and the effective 1D scattering length a1 D diverges. This observation indicates that the molecular formation or atom loss signal in a harmonic waveguide is expected at the magnetic field where a1 D is infinite. Molecule formation is absent at position of the confinement induced resonance which is characterized by the divergence of g1 D . Financial support from Alexander von Humboldt Foundation is acknowledged.

  12. Higher lying resonances in low-energy electron scattering with carbon monoxide*

    NASA Astrophysics Data System (ADS)

    Dora, Amar; Tennyson, Jonathan; Chakrabarti, Kalyan

    2016-10-01

    R-matrix calculations on electron collisions with CO are reported whose aim is to identify any higher-lying resonances above the well-reported and lowest 2Π resonance at about 1.6 eV. Extensive tests with respect to basis sets, target models and scattering models are performed. The final results are reported for the larger cc-pVTZ basis set using a 50 state close-coupling (CC) calculation. The Breit-Wigner eigenphase sum and the time-delay methods are used to detect and fit any resonances. Both these methods find a very narrow 2Σ+ symmetry Feshbach-type resonance very close to the target excitation threshold of the b 3Σ+ state which lies at 12.9 eV in the calculations. This resonance is seen in the CC calculation using cc-pVTZ basis set while a CC calculation using the cc-pVDZ basis set does not produce this feature. The electronic structure of CO- is analysed in the asymptotic region; 45 molecular states are found to correlate with states dissociating to an anion and an atom. Electronic structure calculations are used to study the behaviour of these states at large internuclear separation. Quantitative results for the total, elastic and electronic excitation cross sections are also presented. The significance of these results for models of the observed dissociative electron attachment of CO in the 10 eV region is discussed. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limão-Vieira, Gustavo García, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrović.

  13. Polarization control efficiency manipulation in resonance-mediated two-photon absorption by femtosecond spectral frequency modulation

    NASA Astrophysics Data System (ADS)

    Yao, Yunhua; Cheng, Wenjing; Zheng, Ye; Xu, Cheng; Liu, Pei; Jia, Tianqing; Qiu, Jianrong; Sun, Zhenrong; Zhang, Shian

    2017-04-01

    The femtosecond laser polarization modulation is considered as a very simple and efficient method to control the multi-photon absorption process. In this work, we theoretically and experimentally show that the polarization control efficiency in the resonance-mediated two-photon absorption can be artificially manipulated by modulating the femtosecond spectral frequency components. We theoretically demonstrate that the on- and near-resonant parts in the resonance-mediated two-photon absorption process depend on the different femtosecond spectral frequency components, and therefore their contributions in the whole excitation process can be controlled by properly designing the femtosecond spectral frequency components. The near-resonant two-photon absorption is correlated with the femtosecond laser polarization while the on-resonant two-photon absorption is independent of it, and thus the polarization control efficiency in the resonance-mediated two-photon absorption can be manipulated by the femtosecond spectral frequency modulation. We experimentally verify these theoretical results by performing the laser polarization control experiment in the Dy3+-doped glass sample under the modulated femtosecond spectral frequency components, and the experimental results show that the polarization control efficiency can be increased when the central spectral frequency components are cut off, while it is decreased when both the low and high spectral frequency components are cut off, which is in good agreement with the theoretical predictions. Our works can provide a feasible pathway to understand and control the resonance-mediated multi-photon absorption process under the femtosecond laser field excitation, and also may open a new opportunity to the related application areas.

  14. Resonant x-ray scattering in 3d-transition-metal oxides: Anisotropy and charge orderings

    NASA Astrophysics Data System (ADS)

    Subías, G.; García, J.; Blasco, J.; Herrero-Martín, J.; Sánchez, M. C.

    2009-11-01

    The structural, magnetic and electronic properties of transition metal oxides reflect in atomic charge, spin and orbital degrees of freedom. Resonant x-ray scattering (RXS) allows us to perform an accurate investigation of all these electronic degrees. RXS combines high-Q resolution x-ray diffraction with the properties of the resonance providing information similar to that obtained by atomic spectroscopy (element selectivity and a large enhancement of scattering amplitude for this particular element and sensitivity to the symmetry of the electronic levels through the multipole electric transitions). Since electronic states are coupled to the local symmetry, RXS reveals the occurrence of symmetry breaking effects such as lattice distortions, onset of electronic orbital ordering or ordering of electronic charge distributions. We shall discuss the strength of RXS at the K absorption edge of 3d transition-metal oxides by describing various applications in the observation of local anisotropy and charge disproportionation. Examples of these resonant effects are (I) charge ordering transitions in manganites, Fe3O4 and ferrites and (II) forbidden reflections and anisotropy in Mn3+ perovskites, spinel ferrites and cobalt oxides. In all the studied cases, the electronic (charge and/or anisotropy) orderings are determined by the structural distortions.

  15. a Measurement of the Isovector Giant Quadrupole Resonance in LEAD-208 Using Elastic Polarized Photon Scattering

    NASA Astrophysics Data System (ADS)

    Dale, Daniel Stanton

    This experiment used highly polarized tagged photons to measure polarization asymmetries for elastic scattering in ^{208}Pb in the energy region of the isovector giant quadrupole resonance (IVGQR). These measurements were performed at excitation energies between 16 and 30 MeV. Photons with enhanced linear polarization were obtained from an off-axis tagged photon beam by making a kinematic selection on the post-bremsstrahlung electrons. Scattered photons were detected in two large NaI(Tl) crystals. The polarization asymmetries clearly show the signature for interference between the isovector giant quadrupole resonance and the underlying electric dipole strength. The gross features of the IVGQR strength distribution were obtained in a relatively model independent manner. An isovector giant quadrupole resonance was observed at an excitation energy of 20.1 +/- 0.5 MeV, with a width of 6.3 +/- 0.5 MeV, and an energy weighted strength of 1.4 +/- 0.3 isovector sum rule units.

  16. Spectral signatures of the ionospheric Alfvén resonator to be observed by low-Earth orbit satellite

    NASA Astrophysics Data System (ADS)

    Surkov, V. V.; Pilipenko, V. A.

    2016-03-01

    Interference of an incident and reflected Alfvén pulses propagating inside the ionospheric Alfvén resonator (IAR) is studied on the basis of a simple one-dimensional model. Particular emphasis has been placed on the analysis of spectral features of ultralow frequency (˜1-15 Hz) electric perturbations recently observed by Communications/Navigation Outage Forecasting System satellite. This "fingerprint" multiband spectral structure was observed when satellite descended in the terminator vicinity. Among factors affecting spectral structure the satellite position and distance from the IAR boundaries are most significant. It is concluded that the observed spectrograms exhibit modulation with "period" depending on propagation delay time of reflected Alfvén pulses in such a way that this effect can mask a spectral resonance structure resulted from excitation of IAR eigenmodes. The proposed interference effect is capable to produce a spectral pattern resembling a fingerprint which is compatible with the satellite observations.

  17. Surface-enhanced resonance Raman scattering from methylviologen at a silver electrode: Evidence for two distinct adsorption interactions

    SciTech Connect

    Feng, Qiao; Yue, W.; Cotton, T.M. )

    1990-03-08

    The electronic absorption and resonance Raman spectra of methylviologen radical cation (MV{sup {sm bullet}+}) and fully reduced methylviologen (MV{sup 0}) have been characterized. The enhancement of Raman and resonance Raman (RR) scattering from the dication and its reduction products at polished and roughened silver electrodes was also investigated.

  18. Resonant scattering of 22Na + p studied by the thick-target inverse-kinematic method

    NASA Astrophysics Data System (ADS)

    Jin, S. J.; Wang, Y. B.; Su, J.; Yan, S. Q.; Li, Y. J.; Guo, B.; Li, Z. H.; Zeng, S.; Lian, G.; Bai, X. X.; Liu, W. P.; Yamaguchi, H.; Kubono, S.; Hu, J.; Kahl, D.; Jung, H. S.; Moon, J. Y.; Lee, C. S.; Teranishi, T.; Wang, H. W.; Ishiyama, H.; Iwasa, N.; Komatsubara, T.; Brown, B. A.

    2013-09-01

    Background: In presolar low-density graphite grains, an extraordinarily large 22Ne/20Ne ratio or even nearly pure 22Ne is found, pointing to the condensation of radioactive 22Na in grains. Supernovae and neon-rich novae are the main events that produce 22Na via the explosive hydrogen burning process. The 22Na(p, γ)23Mg reaction is one of the key reactions that influences the 22Na abundance in ejecta.Purpose:The present work aims to explore the proton resonant states in 23Mg relevant to the astrophysical 22Na(p, γ)23Mg reaction. The determined 23Mg resonant parameters can be used to evaluate the 22Na(p, γ)23Mg reaction rate.Method:A low-energy 22Na radioactive ion beam is produced via the 1H(22Ne, 22Na)n reaction, and used to measure the experimental excitation function of the 22Na + p resonant scattering with a conventional thick-target inverse kinematic method. R-matrix analysis is applied to deduce the 23Mg resonance parameters from the experimental excitation function.Results: Three proton resonance states in 23Mg are observed. Spins/parities and the proton partial widths are determined. The deduced excitation energies agree with the compiled values.Conclusions: The new spin and parity assignments allow us to perform a shell-model calculation of the γ widths of the 23Mg resonant states for the evaluation of the 22Na(p, γ)23Mg astrophysical reaction rate. The two s-wave resonant states established in this work at 8.793 and 8.916 MeV in 23Mg, respectively, increase the total reaction rate by about 5% at a temperature greater than 2 GK.

  19. {alpha} resonance structure in {sup 11}B studied via resonant scattering of {sup 7}Li+{alpha}

    SciTech Connect

    Yamaguchi, H.; Hashimoto, T.; Hayakawa, S.; Binh, D. N.; Kahl, D.; Kubono, S.; Wakabayashi, Y.; Kawabata, T.; Teranishi, T.

    2011-03-15

    A new measurement of {alpha} resonant scattering on {sup 7}Li was performed over the excitation energy of 10.2-13.0 MeV in {sup 11}B at the low-energy RI beam facility CNS Radioactive Ion Beam separator (CRIB) of the Center for Nuclear Study (CNS), University of Tokyo. The excitation function of {sup 7}Li+{alpha} at 180 deg. in the center-of-mass system was successfully measured for the first time with the inverse kinematics method, providing important information on the {alpha} cluster structure in {sup 11}B and the reaction rate of {sup 7}Li({alpha},{gamma}), which is relevant to the {sup 11}B production in the {nu} process in core-collapse supernovae. The excitation function of the {sup 7}Li({alpha},p) reaction cross section for 11.7-13.1 MeV was also measured.

  20. Quasi-particle Interference of Heavy Fermions in Resonant X-ray Scattering

    SciTech Connect

    Gyenis, Andras; da Silva Neto, Eduardo H.; Sutarto, Ronny; Schierle, Enrico; He, Feizhou; Weschke, Eugen; Kavai, Mariam; Baumbach, Ryan E.; Thompson, Joe D.; Bauer, Eric D.; Fisk, Zachary; Damascelli, Andrea; Yazdani, Ali; Aynajian, Pegor

    2016-10-14

    Resonant x-ray scattering (RXS) has recently become an increasingly important tool for the study of ordering phenomena in correlated electron systems. Yet, the interpretation of RXS experiments remains theoretically challenging because of the complexity of the RXS cross section. Central to this debate is the recent proposal that impurity-induced Friedel oscillations, akin to quasi-particle interference signals observed with a scanning tunneling microscope (STM), can lead to scattering peaks in RXS experiments. The possibility that quasi-particle properties can be probed in RXS measurements opens up a new avenue to study the bulk band structure of materials with the orbital and element selectivity provided by RXS. We test these ideas by combining RXS and STM measurements of the heavy fermion compound CeMIn5 (M = Co, Rh). Temperature- and doping-dependent RXS measurements at the Ce-M4 edge show a broad scattering enhancement that correlates with the appearance of heavy f-electron bands in these compounds. The scattering enhancement is consistent with the measured quasi-particle interference signal in the STM measurements, indicating that the quasi-particle interference can be probed through the momentum distribution of RXS signals. Overall, our experiments demonstrate new opportunities for studies of correlated electronic systems using the RXS technique.

  1. Density functional simulation of resonant inelastic X-ray scattering experiments in liquids: acetonitrile.

    PubMed

    Niskanen, Johannes; Kooser, Kuno; Koskelo, Jaakko; Käämbre, Tanel; Kunnus, Kristjan; Pietzsch, Annette; Quevedo, Wilson; Hakala, Mikko; Föhlisch, Alexander; Huotari, Simo; Kukk, Edwin

    2016-09-21

    In this paper we report an experimental and computational study of liquid acetonitrile (H3C-C[triple bond, length as m-dash]N) by resonant inelastic X-ray scattering (RIXS) at the N K-edge. The experimental spectra exhibit clear signatures of the electronic structure of the valence states at the N site and incident-beam-polarization dependence is observed as well. Moreover, we find fine structure in the quasielastic line that is assigned to finite scattering duration and nuclear relaxation. We present a simple and light-to-evaluate model for the RIXS maps and analyze the experimental data using this model combined with ab initio molecular dynamics simulations. In addition to polarization-dependence and scattering-duration effects, we pinpoint the effects of different types of chemical bonding to the RIXS spectrum and conclude that the H2C-C[double bond, length as m-dash]NH isomer, suggested in the literature, does not exist in detectable quantities. We study solution effects on the scattering spectra with simulations in liquid and in vacuum. The presented model for RIXS proved to be light enough to allow phase-space-sampling and still accurate enough for identification of transition lines in physical chemistry research by RIXS.

  2. Quasi-particle interference of heavy fermions in resonant x-ray scattering

    PubMed Central

    Gyenis, András; da Silva Neto, Eduardo H.; Sutarto, Ronny; Schierle, Enrico; He, Feizhou; Weschke, Eugen; Kavai, Mariam; Baumbach, Ryan E.; Thompson, Joe D.; Bauer, Eric D.; Fisk, Zachary; Damascelli, Andrea; Yazdani, Ali; Aynajian, Pegor

    2016-01-01

    Resonant x-ray scattering (RXS) has recently become an increasingly important tool for the study of ordering phenomena in correlated electron systems. Yet, the interpretation of RXS experiments remains theoretically challenging because of the complexity of the RXS cross section. Central to this debate is the recent proposal that impurity-induced Friedel oscillations, akin to quasi-particle interference signals observed with a scanning tunneling microscope (STM), can lead to scattering peaks in RXS experiments. The possibility that quasi-particle properties can be probed in RXS measurements opens up a new avenue to study the bulk band structure of materials with the orbital and element selectivity provided by RXS. We test these ideas by combining RXS and STM measurements of the heavy fermion compound CeMIn5 (M = Co, Rh). Temperature- and doping-dependent RXS measurements at the Ce-M4 edge show a broad scattering enhancement that correlates with the appearance of heavy f-electron bands in these compounds. The scattering enhancement is consistent with the measured quasi-particle interference signal in the STM measurements, indicating that the quasi-particle interference can be probed through the momentum distribution of RXS signals. Overall, our experiments demonstrate new opportunities for studies of correlated electronic systems using the RXS technique. PMID:27757422

  3. Quasi-particle Interference of Heavy Fermions in Resonant X-ray Scattering

    DOE PAGES

    Gyenis, Andras; da Silva Neto, Eduardo H.; Sutarto, Ronny; ...

    2016-10-14

    Resonant x-ray scattering (RXS) has recently become an increasingly important tool for the study of ordering phenomena in correlated electron systems. Yet, the interpretation of RXS experiments remains theoretically challenging because of the complexity of the RXS cross section. Central to this debate is the recent proposal that impurity-induced Friedel oscillations, akin to quasi-particle interference signals observed with a scanning tunneling microscope (STM), can lead to scattering peaks in RXS experiments. The possibility that quasi-particle properties can be probed in RXS measurements opens up a new avenue to study the bulk band structure of materials with the orbital and elementmore » selectivity provided by RXS. We test these ideas by combining RXS and STM measurements of the heavy fermion compound CeMIn5 (M = Co, Rh). Temperature- and doping-dependent RXS measurements at the Ce-M4 edge show a broad scattering enhancement that correlates with the appearance of heavy f-electron bands in these compounds. The scattering enhancement is consistent with the measured quasi-particle interference signal in the STM measurements, indicating that the quasi-particle interference can be probed through the momentum distribution of RXS signals. Overall, our experiments demonstrate new opportunities for studies of correlated electronic systems using the RXS technique.« less

  4. Polarization dependence of tip-enhanced Raman and plasmon-resonance Rayleigh scattering spectra

    NASA Astrophysics Data System (ADS)

    Kitahama, Yasutaka; Uemura, Shohei; Katayama, Ryota; Suzuki, Toshiaki; Itoh, Tamitake; Ozaki, Yukihiro

    2017-06-01

    Tip-enhanced Raman scattering (TERS) spectroscopy has high sensitivity and high spatial resolution, although it shows low reproducibility due to the variable optical properties of the tips. In the present study, polarized scattering spectra of localized surface plasmon resonance (LSPR) at the apex of the tip induced by conventional dark field illumination were compared with the corresponding TERS spectra, generated by excitation using polarization not only parallel and perpendicular to the tip, but also vertical to the sample plane (z-polarization). The polarization-dependence of LSPR was consistent with that of the TERS. Thus, the optical properties of the tip can be easily optimized before TERS measurement by excitation polarization that induces the largest LSPR signal.

  5. Giant resonances in {sup 116}Sn from 240 MeV {sup 6}Li scattering

    SciTech Connect

    Chen, X.; Lui, Y.-W.; Clark, H. L.; Tokimoto, Y.; Youngblood, D. H.

    2009-02-15

    Giant resonances in {sup 116}Sn were measured by inelastic scattering of {sup 6}Li ions at E{sub {sup 6}Li}=240 MeV over the angle range 0 deg. - 6 deg. Isoscalar E0-E3 strength distributions were obtained with a double folding model analysis. A total of 106{sub -11}{sup +27}% of the E0 EWSR was found in the excitation energy range from 8 MeV to 30 MeV with a centroid (m{sub 1}/m{sub 0}) energy 15.39{sub -0.20}{sup +0.35} MeV in agreement with results obtained with {alpha} inelastic scattering.

  6. HF(v′ = 3) forward scattering in the F + H2 reaction: Shape resonance and slow-down mechanism

    PubMed Central

    Wang, Xingan; Dong, Wenrui; Qiu, Minghui; Ren, Zefeng; Che, Li; Dai, Dongxu; Wang, Xiuyan; Yang, Xueming; Sun, Zhigang; Fu, Bina; Lee, Soo-Y.; Xu, Xin; Zhang, Dong H.

    2008-01-01

    Crossed molecular beam experiments and accurate quantum dynamics calculations have been carried out to address the long standing and intriguing issue of the forward scattering observed in the F + H2 → HF(v′ = 3) + H reaction. Our study reveals that forward scattering in the reaction channel is not caused by Feshbach or dynamical resonances as in the F + H2 → HF(v′ = 2) + H reaction. It is caused predominantly by the slow-down mechanism over the centrifugal barrier in the exit channel, with some small contribution from the shape resonance mechanism in a very small collision energy regime slightly above the HF(v′ = 3) threshold. Our analysis also shows that forward scattering caused by dynamical resonances can very likely be accompanied by forward scattering in a different product vibrational state caused by a slow-down mechanism. PMID:18434547

  7. HF(v' = 3) forward scattering in the F + H2 reaction: shape resonance and slow-down mechanism.

    PubMed

    Wang, Xingan; Dong, Wenrui; Qiu, Minghui; Ren, Zefeng; Che, Li; Dai, Dongxu; Wang, Xiuyan; Yang, Xueming; Sun, Zhigang; Fu, Bina; Lee, Soo-Y; Xu, Xin; Zhang, Dong H

    2008-04-29

    Crossed molecular beam experiments and accurate quantum dynamics calculations have been carried out to address the long standing and intriguing issue of the forward scattering observed in the F + H(2) --> HF(v' = 3) + H reaction. Our study reveals that forward scattering in the reaction channel is not caused by Feshbach or dynamical resonances as in the F + H(2) --> HF(v' = 2) + H reaction. It is caused predominantly by the slow-down mechanism over the centrifugal barrier in the exit channel, with some small contribution from the shape resonance mechanism in a very small collision energy regime slightly above the HF(v' = 3) threshold. Our analysis also shows that forward scattering caused by dynamical resonances can very likely be accompanied by forward scattering in a different product vibrational state caused by a slow-down mechanism.

  8. Dissociation of Physisorbed H2 through Low-Energy Electron Scattering Resonances

    NASA Astrophysics Data System (ADS)

    Andersson, S.; Svensson, K.

    2010-05-01

    Electron induced dissociation of physisorbed H2, HD, and D2 proceeds, as we observe in electron energy-loss measurements of the resulting atomic species, with a high quantum efficiency via the Σg+2 core excited electron scattering resonances. We find that the predominant decay of the temporary H2- state to the neutral excited Σu+3 parent state, which is intramolecularly antibonding, provides a sufficiently long-lived channel for dissociation to occur with high probability, even in the proximity of a metal surface.

  9. Microdetermination of proteins by resonance light scattering spectroscopy with bromophenol blue.

    PubMed

    Ma, C Q; Li, K A; Tong, S Y

    1996-07-15

    Reaction of bromophenol blue with proteins results in an enhanced resonance light scattering at 334 nm. Based on this, a new quantitative determination method for proteins in the aqueous solution is established. This assay is characterized by high sensitivity (0.34-18.7 microg/ml), short reaction time (>2 min), and simplicity (a one-step assay). Due to protein-to-protein variability, this method gave results higher than that of the bromocresol green assay in detection of human serum albumin.

  10. Paramagnon excitations' theory for resonant inelastic X-ray scattering in doped plane copper oxide superconductors

    NASA Astrophysics Data System (ADS)

    Larionov, I. A.

    2015-04-01

    A relaxation function theory with paramagnon excitations for doped S = 1 / 2 two-dimensional Heisenberg antiferromagnetic system in the paramagnetic state is given in view of magnetic response of high-Tc copper oxide superconductors as obtained by resonant inelastic X-ray scattering (RIXS). The results of the theory on Nd(La)-Ba(Sr)-Cu-O and Y-Ba-Cu-O family compounds give fair agreement without especially adjusted parameters to RIXS data. It is shown that RIXS data analysis depends on paramagnon damping and thus affected by approximations made for dynamic spin susceptibility.

  11. Numerical study of Resonant inelastic x-ray scattering for cuprates and transition-metal oxides

    NASA Astrophysics Data System (ADS)

    Jia, Chunjing; Wang, Yao; Chen, Cheng-Chien; Moritz, Brian; Devereaux, Thomas

    A theoretical understanding of resonant inelastic x-ray scattering (RIXS) measurements on cuprates and other transition-metal oxides remains an important yet challenging topic, especially for its ability to resolve the momentum and photon-polarization dependence of low energy elementary excitations. Here we present our exact diagonalization studies for RIXS spectra at the Cu L-edge for cuprates, with a focus on the dependence of both incoming and outgoing photon polarization and incoming photon energy. A more general method for calculating RIXS on other transition-metal oxides (such as NiO), which includes the multiplet and charge-transfer effects, will also be discussed.

  12. Surface-enhanced resonance Raman scattering in optical tweezers using co-axial second harmonic generation.

    PubMed

    Jordan, Pamela; Cooper, Jon; McNay, Graeme; Docherty, Frances; Graham, Duncan; Smith, W; Sinclair, Gavin; Padgett, Miles

    2005-05-30

    Silica particles were partially coated with silver, and a suitable chromophore, such that they could be simultaneously trapped within an optical tweezers system, and emit a surface-enhanced resonance Raman scattering (SERRS) response. A standard 1064 nm TEM00 mode laser was used to trap the bead whilst a frequency doubling crystal inserted into the beam gave several microwatts of 532 nm co-linear light to excite the SERRS emission. The con fi guration has clear applications in providing apparatus that can simultaneously manipulate a particle whilst obtaining surface sensitive sensory information.

  13. Surface plasmon resonance and surface-enhanced Raman scattering sensing enabled by digital versatile discs

    NASA Astrophysics Data System (ADS)

    Dou, Xuan; Chung, Pei-Yu; Jiang, Peng; Dai, Jianli

    2012-01-01

    We report the simultaneous achievement of sensitive surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS) sensing using digital versatile discs (DVDs). The aluminum-covered data tracks of DVDs can efficiently concentrate local electromagnetic field, resulting in an excellent SPR medium (with sensitivity of ˜850 nm per refractive index unit which is higher than that of most available nanofabricated plasmonic substrates) with a small but measurable SERS enhancement. The SPR sensitivity and the optical spectra, as well as the distribution of electric field amplitude, are simulated using a finite-difference time-domain model. The theoretical predictions agree reasonably well with the experimental results.

  14. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

    PubMed Central

    Bi, Wenli; Zhao, Jiyong; Lin, Jung-Fu; Jia, Quanjie; Hu, Michael Y.; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E. Ercan

    2015-01-01

    A new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal–insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu57Fe2As2 at high pressure and low temperature were derived by using this new capability. PMID:25931094

  15. Resonant proton scattering on 46Ar using the Active-Target Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Bradt, J.; Ahn, T.; Ayyad Limonge, Y.; Bazin, D.; Beceiro Novo, S.; Carpenter, L.; Kuchera, M. P.; Lynch, W.; Mittig, W.; Rost, S.; Watwood, N.; Barney, J.; Datta, U.; Estee, J.; Gillibert, A.; Manfredi, J.; Morfouace, P.; Perez Loureiro, D.; Pollacco, E.; Sammut, J.; Sweany, S.

    2016-09-01

    A well-known technique for studying the single-particle properties of neutron-rich nuclei is to use resonant proton scattering on a parent nucleus to populate the isobaric analog states of the corresponding neutron-rich nucleus. The locations and amplitudes of these resonances are directly related to the structure of the nucleus of interest by isospin symmetry. We performed an experiment of this type at the National Superconducting Cyclotron Laboratory to commission the recently completed Active-Target Time Projection Chamber (AT-TPC). A 4.6-MeV/u radioactive beam of 46Ar was injected into the AT-TPC. The detector was filled with isobutane gas-which provided the protons for the reaction and served as the tracking medium-and placed inside a 2-T magnetic field. We will present preliminary results from this experiment and discuss the benefits of the active-target method for this type of measurement.

  16. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature.

    PubMed

    Bi, Wenli; Zhao, Jiyong; Lin, Jung-Fu; Jia, Quanjie; Hu, Michael Y; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E Ercan

    2015-05-01

    A new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal-insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu(57)Fe2As2 at high pressure and low temperature were derived by using this new capability.

  17. Near- and far-field scattering resonance frequency shift in dielectric and perfect electric conducting cylinders.

    PubMed

    Yuffa, Alex J; Gutierrez, Yael; Sanz, Juan M; Alcaraz de la Osa, Rodrigo; Saiz, José M; González, Francisco; Moreno, Fernando; Videen, Gorden

    2016-03-01

    The ability to infer near-field scattering properties from far-field measurements is of paramount importance in nano-optics. Recently we derived an approximate formula for predicting the frequency shift between near- and far-field intensity peaks in the case of a dielectric sphere. In this work we demonstrate that almost an identical formula can be used to predict the resonance shift of a dielectric cylinder and a perfectly conducting cylinder. We find the redshift of the resonance peak of the perfect electric conducting cylinder to be approximately 2 orders of magnitude greater than for the dielectric cylinder. The errors in our approximate analytic formula for predicting the redshift are approximately only twice as great. Furthermore, we apply the redshift formula to a silicon cylinder and discuss its magneto-dielectric properties, which may be of interest in design of metamaterials.

  18. Pressure-induced depolarization and resonance in Raman scattering of single-crystalline boron carbide

    SciTech Connect

    Guo Junjie; Zhang Ling; Fujita, Takeshi; Chen Mingwei; Goto, Takashi

    2010-02-01

    We report polarized and resonant Raman scattering of single-crystal boron carbide (B{sub 4}C) at high pressures. Significant intensity enhancements of 270 and 1086 cm{sup -1} Raman bands of B{sub 4}C have been observed at quasihydrostatic pressures higher than approx20 GPa. The pressure-induced intensity change of the 1086 cm{sup -1} band is mainly due to the resonance between excitation energy and electronic transition, whereas the intensity change of 270 cm{sup -1} band is caused by the depolarization effect. Importantly, the first-order phase transition has not been found at high quasihydrostatic pressures and all the Raman intensity changes along with the corresponding high-pressure lattice distortion can be recovered during unloading.

  19. An investigation of resonances in e{sup +}-H scattering embedded in Debye plasma

    SciTech Connect

    Ning, Ye; Yan, Zong-Chao; Ho, Yew Kam

    2015-01-15

    We carry out calculations for S-wave and P-wave resonances in e{sup +}-H scattering in weakly coupled Debye plasma in which the interaction between two charged particles is represented by a screened Coulomb potential. We employ the complex-scaling method with Hylleraas-type basis set to take correlation effects into account. In the complex-scaling treatment of the screened Coulomb potential, we first perform a Taylor series expansion for the exponential function that contains the distance r between two particles into a polynomial with various powers r{sup n}. We then make the complex scaling transformation of r→r e{sup iθ} in the expansion. The complex resonant eigenvalues are obtained by searching for stabilized points in the complex energy plane with respect to the changes of rotational angle θ and other parameters in the basis set.

  20. A New Scaling Law of Resonance in Total Scattering Cross Section in Gases

    NASA Astrophysics Data System (ADS)

    Raju, Gorur Govinda

    2009-10-01

    Electrical discharges in gases continue to be an active area of research because of industrial applications such as power systems, environmental clean up, laser technology, semiconductor fabrication etc. A fundamental knowledge of electron-gas neutral interaction is indispensable and, the total scattering cross section is one of the quantities that have been measured extensively. The energy dependence of the total cross sections shows peaks or resonance processes that are operative in the collision process. These peaks and the energies at which they occur are shown to satisfy a broad relationship involving the polarizability and the dipole moment of the target particle. Data on 62 target particles belonging to the following species are analyzed. (Eq 1) Rare gas atoms (Eq 2) Di-atomic molecules with combinations of polar, non-polar, attaching, and non-attaching properties Poly-atomic molecules with combinations of polar, non-polar, attaching, and non-attaching properties. Methods of improving the newly identified scaling law and possible application have been identified. 1 INTRODUCTION: Data on electron-neutral interactions are one of the most fundamental in the study of gaseous electronics and an immense literature, both experimental and theoretical, has become available since about the year 1920. [1-5]. In view of the central role which these data play in all facets of gas discharges and plasma science, it is felt that a critical review of available data is timely, mainly for the community of high voltage engineers and industries connected with plasma science in general. The electron-neutral interaction, often referred to as scattering in the scientific literature, is quantified by using the quantity called the total scattering cross section (QT, m^2). In the literature on cross section, total cross section and total scattering cross section are terms used synonymously and we follow the same practice. A definition may be found in reference [1]. This paper concerns