Practical way to avoid spurious geometrical contributions in Brillouin light scattering experiments at variable scattering angles.

Science.gov (United States)

Battistoni, Andrea; Bencivenga, Filippo; Fioretto, Daniele; Masciovecchio, Claudio

2014-10-15

In this Letter, we present a simple method to avoid the well-known spurious contributions in the Brillouin light scattering (BLS) spectrum arising from the finite aperture of collection optics. The method relies on the use of special spatial filters able to select the scattered light with arbitrary precision around a given value of the momentum transfer (Q). We demonstrate the effectiveness of such filters by analyzing the BLS spectra of a reference sample as a function of scattering angle. This practical and inexpensive method could be an extremely useful tool to fully exploit the potentiality of Brillouin acoustic spectroscopy, as it will easily allow for effective Q-variable experiments with unparalleled luminosity and resolution.

Effects of pump recycling technique on stimulated Brillouin scattering threshold: a theoretical model.

Science.gov (United States)

Al-Asadi, H A; Al-Mansoori, M H; Ajiya, M; Hitam, S; Saripan, M I; Mahdi, M A

2010-10-11

We develop a theoretical model that can be used to predict stimulated Brillouin scattering (SBS) threshold in optical fibers that arises through the effect of Brillouin pump recycling technique. Obtained simulation results from our model are in close agreement with our experimental results. The developed model utilizes single mode optical fiber of different lengths as the Brillouin gain media. For 5-km long single mode fiber, the calculated threshold power for SBS is about 16 mW for conventional technique. This value is reduced to about 8 mW when the residual Brillouin pump is recycled at the end of the fiber. The decrement of SBS threshold is due to longer interaction lengths between Brillouin pump and Stokes wave.

Stimulated Brillouin scattering threshold in fiber amplifiers

International Nuclear Information System (INIS)

Liang Liping; Chang Liping

2011-01-01

Based on the wave coupling theory and the evolution model of the critical pump power (or Brillouin threshold) for stimulated Brillouin scattering (SBS) in double-clad fiber amplifiers, the influence of signal bandwidth, fiber-core diameter and amplifier gain on SBS threshold is simulated theoretically. And experimental measurements of SBS are presented in ytterbium-doped double-clad fiber amplifiers with single-frequency hundred nanosecond pulse amplification. Under different input signal pulses, the forward amplified pulse distortion is observed when the pulse energy is up to 660 nJ and the peak power is up to 3.3 W in the pulse amplification with pulse duration of 200 ns and repetition rate of 1 Hz. And the backward SBS narrow pulse appears. The pulse peak power equals to SBS threshold. Good agreement is shown between the modeled and experimental data. (authors)

Spontaneous Rayleigh-Brillouin scattering spectral analysis based on the Wiener filter

Directory of Open Access Journals (Sweden)

Tao Wu

2018-01-01

Full Text Available In this paper, a spontaneous Rayleigh-Brillouin scattering spectrometer is developed to measure the gaseous spontaneous Rayleigh-Brillouin scattering profiles over the pressure range from 1 to 5 atm for a wavelength of 532nm at a constant room temperature of 296K and a 90o scattering angle. In order to make a direct comparison between the experimentally obtained spectrum and the theoretical spectrum calculated from the Tenti S6 model, the measured spontaneous Rayleigh-Brillouin scattering signal is deconvolved by the Wiener filtering. The purpose is to remove the effect on the spectrum by the transmission function of the Fabry-Perrot scanning interferometer. The results of the comparison show that the deconvolved spectra are consistent with the theoretical spectra calculated from the Tenti S6 model, and thus confirm that the deconvolution based on the Wiener filter is able to process the measured spectra and improve the spectral resolution. Some factors that influence the accuracy of deconvolution are analyzed and discussed. At the same time, another comparison between the raw experimentally obtained spectra and the theoretical spectra calculated by convolving the Tenti S6 model with instrument function of the measurement system is performed in the same experimental condition. The results of the two comparisons show that, compared with the raw experimentally obtained spectrum, the deconvolved spectrum matches the theoretically calculated spectrum more accurately under lower pressure (≤2atm than under relative higher pressure (>2atm.

Highly localized distributed Brillouin scattering response in a photonic integrated circuit

Science.gov (United States)

Zarifi, Atiyeh; Stiller, Birgit; Merklein, Moritz; Li, Neuton; Vu, Khu; Choi, Duk-Yong; Ma, Pan; Madden, Stephen J.; Eggleton, Benjamin J.

2018-03-01

The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS) has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.

Highly localized distributed Brillouin scattering response in a photonic integrated circuit

Directory of Open Access Journals (Sweden)

Atiyeh Zarifi

2018-03-01

Full Text Available The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.

Investigation of the Stimulated Brillouin Scattering (SBS) Gain Enhancement in Silicon Nano-Waveguides and Applications

OpenAIRE

Al-Taiy, Hassanain Majeed

2017-01-01

Stimulated Brillouin scattering is a third order non-linear effect with the lowest power threshold in standard single mode optical fiber, by which an interaction between optical and acoustic modes takes place. During the Brillouin scattering process, part of the pump wave power will be transferred to a counter propagating wave (Stokes), with a frequency shift of about 11 GHz for a telecommunication wavelength of 1550 nm in a standard single mode fiber. The frequency shift effective parameters...

Geophysical Remote Sensing Using the HF Pumped Stimulated Brillouin Scatter (SBS) Emission Lines Produced by HAARP

Science.gov (United States)

Bernhardt, P. A.; Selcher, C. A.

2009-12-01

An ordinary or extraordinary mode electromagnetic wave can decay into a low frequency electrostatic wave and a scattered electromagnetic wave by a process called stimulated Brillouin scatter (SBS). The low frequency wave can be either an ion acoustic wave (IA) or an electrostatic ion cyclotron (EIC) wave. The first detection ion acoustic waves by this process during ionospheric modification with high power radio waves was reported by Norin et al. (2009) using the HAARP transmitter in Alaska. The first detection of the electrostatic ion cyclotron waves is reported here using HAARP during the March 2009 campaign. Subsequent experiments have provided additional verification of the SBS process and quantitative interpretation of the scattered wave frequency offsets to yield measurements of the electron temperatures in the heated ionosphere by Bernhardt et al. (2009). Using the SBS technique to generate ion acoustic waves, electron temperatures between 3000 and 4000 K were measured over the HAARP facility. The matching conditions for decay of the high frequency pump wave show that in addition to the production of an ion-acoustic wave, an electrostatic ion cyclotron wave can produced by the generalized SBS processes only if the pump waves makes a large angle with the magnetic field. When the EIC mode is produced, it is seen as a narrow of stimulated electromagnetic emissions at the ion cyclotron frequency. Occasionally, multiple lines are seen and analyzed to yield the relative abundance of oxygen, and molecular ions in the lower ionosphere. This ion mass spectrometer interpretation of the SBS data is new to the field of ionosphere remote sensing. In addition, based on the matching condition theory, the first profiles of the scattered wave amplitude are produced using the stimulated Brillouin scatter (SBS) matching conditions. These profiles are consistent with maximum ionospheric interactions at the upper-hybrid resonance height and at a region just below the plasma

The broad Brillouin doublet and CP of KTaO3, second sound vs. Two-phonon difference scattering

International Nuclear Information System (INIS)

Farhi, E.; Tagantsev, A.K.; Hehlen, B.; Courtens, E.; Boatner, L.A.

1999-01-01

Complete text of publication follows. Low-T Brillouin spectra of the incipient ferroelectric KTaO 3 exhibit a broad central peak (CP) (1), and some additional broad Brillouin doublet (BD) (2), that can both relate to phonon-density fluctuations (3). Starting from extensive new high resolution neutron scattering measurements in pure crystals, low lying phonon sheets were modelled in the central part of Brillouin zone. Such a parameterisation was then used in order to analyse those up-mentioned unusual features in teens of two-phonon mechanisms (4). Numerical evaluations show that transverse acoustic (TA) phonons whose normal damping is faster than the BD frequency (Γ DB > ω DB ) may produce hydrodynamic second sound (propagation of heat). Moreover, two-phonon difference scattering from low damping thermal TA phonons ((Γ DB DB ) can contribute to the spectra with either a sharp or a broader BD, depending on the phonon group velocity and phonon-sheet anisotropy. The position of the doublet is consistent with both mechanisms, but comparing the computed anisotropies with experimental Brillouin and neutron scattering data, one favours the second process. (author)

Measurement of sound velocity on metal surfaces by impulsive stimulated Brillouin scattering

International Nuclear Information System (INIS)

Shimada, Yukihiro; Murakami, Hiroshi; Nishimura, Akihiko

2005-01-01

Impulsive stimulated Brillouin Scattering (ISBS) experiment was performed in order to measure acoustic waves on metal surfaces. The ISBS technique offers robust method of obtaining acoustic velocities without physical contact. The generation and detection mechanism were discussed. (author)

Brillouin light scattering studies of the mechanical properties of ultrathin low-k dielectric films

Science.gov (United States)

Link, A.; Sooryakumar, R.; Bandhu, R. S.; Antonelli, G. A.

2006-07-01

In an effort to reduce RC time delays that accompany decreasing feature sizes, low-k dielectric films are rapidly emerging as potential replacements for silicon dioxide (SiO2) at the interconnect level in integrated circuits. The main challenge in low-k materials is their substantially weaker mechanical properties that accompany the increasing pore volume content needed to reduce k. We show that Brillouin light scattering is an excellent nondestructive technique to monitor and characterize the mechanical properties of these porous films at thicknesses well below 200nm that are pertinent to present applications. Observation of longitudinal and transverse standing wave acoustic resonances and the dispersion that accompany their transformation into traveling waves with finite in-plane wave vectors provides for a direct measure of the principal elastic constants that completely characterize the mechanical properties of these ultrathin films. The mode amplitudes of the standing waves, their variation within the film, and the calculated Brillouin intensities account for most aspects of the spectra. We further show that the values obtained by this method agree well with other experimental techniques such as nanoindentation and picosecond laser ultrasonics.

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

NARCIS (Netherlands)

Witschas, B.; Vieitez, M.O.; Duijn, van E.-J.; Reitebuch, O.; Water, van de W.; Ubachs, W.

2010-01-01

Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh–Brillouin scattering measurements in the ultraviolet at a

Influence of core diameter and length of polymer optical fiber on Brillouin scattering properties

Science.gov (United States)

Mizuno, Yosuke; Ishigure, Takaaki; Nakamura, Kentaro

2012-02-01

Brillouin scattering in perfluorinated graded-index polymer optical fibers (PFGI-POFs) is potentially useful in developing high-accuracy distributed temperature sensors with reduced strain sensitivity. In this study, we investigate, both experimentally and theoretically, the influence of the fiber core diameter and length on the Brillouin gain spectra (BGS) in PFGI-POFs. First, we show that smaller core diameter drastically enhances the Stokes power using PFGI-POFs with 62.5-μm and 120-μm core diameters, and discuss the Brillouin threshold power. Then, we demonstrate that the PFGI-POF length has little influence on the BGS when the length is longer than 50 m. We also predict that, at 1.55-μm wavelength, it is difficult to reduce the Brillouin threshold power of PFGI-POFs below that of long silica single-mode fibers even if their core diameter is sufficiently reduced to satisfy the single-mode condition. Finally, making use of the enhanced Stokes signal, we confirm the Brillouin linewidth narrowing effect.

Single-mode Brillouin fiber laser passively stabilized at resonance frequency with self-injection locked pump laser

International Nuclear Information System (INIS)

Spirin, V V; Lopez-Mercado, C A; Megret, P; Fotiadi, A A

2012-01-01

We demonstrate a single-mode Brillouin fiber ring laser, which is passively stabilized at pump resonance frequency by using self-injection locking of semiconductor pump laser. Resonance condition for Stokes radiation is achieved by length fitting of Brillouin laser cavity. The laser generate single-frequency Stokes wave with linewidth less than 0.5 kHz using approximately 17-m length cavity

Rayleigh-Brillouin scattering in SF6 in the kinetic regime

NARCIS (Netherlands)

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

2017-01-01

Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2–5 bar and for a wavelength of λ=403.0 nm. The

Fiber-integrated Brillouin microspectroscopy: Towards Brillouin endoscopy

Directory of Open Access Journals (Sweden)

Irina V. Kabakova

2017-11-01

Full Text Available Brillouin imaging (BI for micromechanical characterization of tissues and biomaterials is a fast-developing field of research with a strong potential for medical diagnosis of disease-modified tissues and cells. Although the principles of BI imply its compatibility with in vivo and in situ measurements, the integration of BI with a flexible catheter, capable of reaching the region of interest within the body, is yet to be reported. Here, for the first time, we experimentally investigate integration of the Brillouin spectroscope with standard optical fiber components to achieve a Brillouin endoscope. The performance of single-fiber and dual-fiber endoscopes are demonstrated and analyzed. We show that a major challenge in construction of Brillouin endoscopes is the strong backward Brillouin scattering in the optical fiber and we present a dual-fiber geometry as a possible solution. Measurements of Brillouin spectra in test liquids (water, ethanol and glycerol are demonstrated using the dual-fiber endoscope and its performance is analyzed numerically with the help of a beam propagation model.

Brillouin Spectroscopy Data Base for Biological Threats

National Research Council Canada - National Science Library

Rubel, Glenn

2003-01-01

.... Brillouin scattering from DNA, ovalbumen, the Bacillus spores globigii and thuringiensis were measured to determine the feasibility of biological material discrimination using Brillouin scattering...

Tunable Stimulated Brillouin Scattering in Planar Optical Circuits

Science.gov (United States)

2012-11-01

J. Gauthier, R. W. Boyd, and A. L. Gaeta, Phys. Rev. Lett. 94, 153902 (2005). 4. R. Pant, M. D. Stenner , M. A. Neifeld, and D. J. Gauthier, Opt...Express 16, 2764 (2008). 5. Z. Shi, R. Pant, Z. Zhu, M. D. Stenner , M. A. Neifeld, D. J. Gauthier, and R. W. Boyd, Opt. Lett. 32, 1986 (2007). 6. K. Y...stimulated Brillouin scattering,” Opt. Express 19(9), 8285–8290 (2011). 25. R. Pant, M. D. Stenner , M. A. Neifeld, Z. M. Shi, R. W. Boyd, and D. J

Brillouin light scattering studies on the mechanical properties of ultrathin, porous low-K dielectric films

Science.gov (United States)

Zhou, Wei; Sooryakumar, R.; King, Sean

2010-03-01

Low K dielectrics have predominantly replaced silicon dioxide as the interlayer dielectric material for interconnects in state of the art integrated circuits. To further reduce interconnect resistance-capacitance (RC) delays, additional reductions in the K for these low-K materials is being pursued by the introduction of controlled levels of porosity. The main challenge for porous low-K dielectrics is the substantial reduction in mechanical properties that is accompanied by the increased pore volume content needed to reduce K. We report on the application of the nondestructive Brillouin light scattering technique to monitor and characterize the mechanical properties of these porous films at thicknesses well below 200 nm that are pertinent to present applications. Observation of longitudinal and transverse standing wave acoustic resonances and the dispersion that accompany their transformation into traveling waves with finite in-plane wave vectors provides for the principal elastic constants that completely characterize the mechanical properties of these porous films. The mode amplitudes of the standing waves, their variation within the film, and the calculated Brillouin intensities account for most aspects of the spectra. The resulting elastic constants are compared with corresponding values obtained from other experimental techniques.

Fiber break location technique utilizing stimulated Brillouin scattering effects in optical fiber

International Nuclear Information System (INIS)

Bakar, A A A; Al-Mansoori, M H; Mahdi, M A; Mohd Azau, M A; Zainal Abidin, M S

2009-01-01

A new technique of fiber break detection system in optical communication networks is proposed and experimentally demonstrated in this paper. This technique is based-on continuous wave light source rather than pulsed source that is commonly deployed in existing techniques. The nonlinear effect of stimulated Brillouin scattering is manipulated to locate the fiber-break position in optical communication networks. This technique enables the utilization of a less-sensitive photodetector to detect the Brillouin Stokes line since its intensity increases with the fiber length in the detectable region. The fiber break location can be determined with accuracy of more than 98% for fiber length less than 50 km using this technique

Rayleigh-Brillouin scattering in NH4Cl under hydrostatic pressure

International Nuclear Information System (INIS)

Hikita, Tomoyuki; Kitabatake, Makoto; Ikeda, Takuro

1981-01-01

Rayleigh-Brillouin scattering in NH 4 Cl has been studied under hydrostatic pressure. Brillouin shifts of the longitudinal phonons propagating along the and directions and of the transverse phonons propagating along the direction are measured as a function of temperature at four fixed pressures up to 2.3 kbar. All components increase almost linearly with decreasing temperature in the disordered phase and show incremental increases similar to the temperature dependence of the long range order parameter in the ordered phase. It was found that the longitudinal modes exhibit large despersion effect even at high pressures. On the other hand, the transverse mode appears to give no dispersion effect. The intensity of the Rayleigh component in the VV polarization condition increases as the temperature approaches the transition point, while that in the VH polarization does not show such anomalous increase. (author)

Stimulated brillouin scattering of electromagnetic waves in a dusty plasma

International Nuclear Information System (INIS)

Salimullah, M.; Sen, A.

1991-08-01

The stimulated Brilluoin scattering of electromagnetic waves in a homogeneous, unmagnetized and collisionless dusty plasma has been investigated theoretically. The Vlasov equation has been solved perturbatively to find the nonlinear response of the plasma particles. The presence of the dust particles introduces a background inhomogeneous electric field which significantly influences the dispersive properties of the plasma. At the ion acoustic branch we find the usual scattering slightly modified by the charged dust grains. However, at the frequency lower than the ion acoustic branch we find a new mode of the plasma arising from the oscillations of the ions in the static structure of the dust distribution. This low frequency branch causes enhanced stimulated Brillouin scattering of electromagnetic waves in a dusty plasma. (author). 15 refs

SBS [stimulated Brillouin scattering] pulse distortion in multimode optical fibers

International Nuclear Information System (INIS)

Smith, J.R.; Hawkins, R.J.; Laumann, C.W.; Hatch, J.

1989-01-01

We have observed sever temporal-pulse-shape distortion due to stimulated Brillouin scattering (SBS) in multimode optical fibers used to diagnose 351 m laser pulses on the Nova laser system. Our measurements can be fit by a basic model of SBS and provide a clear indication of the intensity and temporal regimes where significant SBS-induced temporal-pulse-shape distortion can be avoided. 15 refs., 3 figs., 1 tab

Experimental observation of spontaneous depolarized guided acoustic-wave Brillouin scattering in side cores of a multicore fiber

Science.gov (United States)

Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro; Set, Sze Yun; Yamashita, Shinji

2018-06-01

Spontaneous depolarized guided acoustic-wave Brillouin scattering (GAWBS) was experimentally observed in one of the side cores of an uncoated multicore fiber (MCF). The frequency bandwidth in the side core was up to ∼400 MHz, which is 0.5 times that in the central core. The GAWBS spectrum of the side core of the MCF included intrinsic peaks, which had different acoustic resonance frequencies from those of the central core. In addition, the spontaneous depolarized GAWBS in the central/side core was unaffected by that in the other core. These results will lead to the development of polarization/phase modulators using an MCF.

Physics of the ion acoustic wave driven by the stimulated Brillouin scattering instability

International Nuclear Information System (INIS)

Clayton, C.E.

1984-01-01

The ion acoustic wave excited in the stimulated Brillouin scattering (SBS) instability is probed via collective ruby-laser Thomson scattering in order to understand the low saturation level observed in the instability. Many of the features observed in the Brillouin backscattered CO 2 laser light from the underdense gas-target plasma are also observed in the Thomson scattered ruby light - from which it is learned that the ion acoustic wave grows exponentially and then saturates as the CO 2 pump power is increased. The primary advantage of the ruby Thomson scattering diagnostic is in its capability of providing simultaneous space and time resolved measurements of the ion wave amplitude. From these first such detailed measurements, it was found that the ion wave grows exponentially in space at a rate that agrees with the linear convective SBS theory. However, at higher pump powers, the ion wave saturates at an inferred amplitude of anti-n/n 0 approx. = 5 to 10%. Further increases in the pump power appear to result in an increase in the length over which the ion wave is saturated. A nearly constant SBS reflectivity in this saturated regime, however, suggests that the saturated ion wave does not contribute as much to the scattered power as would be expected from Bragg scattering theory. This apparent contradiction can be resolved if ion trapping is responsible for the saturation of the ion wave

Inhibition of stimulated Raman scattering due to the excitation of stimulated Brillouin scattering

Science.gov (United States)

Zhao, Yao; Yu, Lu-Le; Weng, Su-Ming; Ren, Chuang; Liu, Chuan-Sheng; Sheng, Zheng-Ming

2017-09-01

The nonlinear coupling between stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) of intense laser in underdense plasma is studied theoretically and numerically. Based upon the fluid model, their coupling equations are derived, and a threshold condition of plasma density perturbations due to SBS for the inhibition of SRS is given. Particle-in-cell simulations show that this condition can be achieved easily by SBS in the so-called fluid regime with kLλDDebye length [Kline et al., Phys. Plasmas 13, 055906 (2006)]. SBS can reduce the saturation level of SRS and the temperature of electrons in both homogeneous and inhomogeneous plasma. Numerical simulations also show that this reduced SRS saturation is retained even if the fluid regime condition mentioned above is violated at a later time due to plasma heating.

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

Directory of Open Access Journals (Sweden)

G. Shimon

2015-09-01

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

Guided acoustic and optical waves in silicon-on-insulator for Brillouin scattering and optomechanics

Directory of Open Access Journals (Sweden)

Christopher J. Sarabalis

2016-10-01

Full Text Available We numerically study silicon waveguides on silica showing that it is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator (SOI material system. Thin waveguides, or fins, exhibit geometrically softened mechanical modes at gigahertz frequencies with phase velocities below the Rayleigh velocity in glass, eliminating acoustic radiation losses. We propose slot waveguides on glass with telecom optical frequencies and strong radiation pressure forces resulting in Brillouin gains on the order of 500 and 50 000 W−1m−1 for backward and forward Brillouin scattering, respectively.

Coherent Forward Stimulated-Brillouin Scattering of a Spatially Incoherent Laser Beam in a Plasma and Its Effect on Beam Spray

International Nuclear Information System (INIS)

Grech, M.; Riazuelo, G.; Pesme, D.; Weber, S.; Tikhonchuk, V. T.

2009-01-01

A statistical model for forward stimulated-Brillouin scattering is developed for a spatially incoherent, monochromatic, laser beam propagating in a plasma. The threshold above which the laser beam spatial incoherence cannot prevent the coherent growth of forward stimulated-Brillouin scattering is computed. It is found to be well below the threshold for self-focusing. Three-dimensional simulations confirm its existence and reveal the onset of beam spray above it. From these results, we propose a new figure of merit for the control of propagation through a plasma of a spatially incoherent laser beam

Resonating rays in ion-ion scattering from an optical potential

International Nuclear Information System (INIS)

Farhan, A.R.; Stoyanov, B.J.; Nagl, A.; Uberall, H.; de Llano, M.

1986-01-01

The amplitude of ion-ion scattering, described, e.g., by an optical potential, separates into a ''surface-wave'' part (which, as shown before, may give rise to resonances) and a ''geometrical-ray'' part. The amplitude as alternately expressed here by the Wentzel-Kramers-Brillouin approximation resolves into an externally reflected ''barrier wave'' and into ''internal'' or ''penetrating rays'' that undergo an internal reflection together with possible additional multiple reflections. Our numerical calculations show that resonances also occur in the penetrating rays, which take place when a characteristic equation is satisfied. The geometrical meaning of the latter is determined by the optical path length of penetration being an integer multiple of π, plus a 1/2π caustic phase jump, and an extra phase shift due to barrier penetration

Development of a Brillouin scattering based distributed fibre optic strain sensor

Science.gov (United States)

Brown, Anthony Wayne

2001-07-01

The parameters of the Brillouin spectrum of an optical fibre depend upon the strain and temperature conditions of the fibre. As a result, fibre optic distributed sensors based on Brillouin scattering can measure strain and temperature in arbitrary regions of a sensing fibre. In the past, such sensors have often been demonstrated under laboratory conditions, demonstrating the principle of operation. Although some field tests of temperature sensing have been reported, the actual deployment of such sensors in the field for strain measurements has been limited by poor spatial resolution (typically 1 m or more) and poor strain accuracy (+/-100 muepsilon). Also, cross-sensitivity of the Brillouin spectrum to temperature further reduces the accuracy of strain measurement while long acquisition times hinders field use. The high level of user knowledge and lack of automation required to operate the equipment is another limiting factor of the only commercially available unit. The potential benefits of distributed measurements are great for instrumentation of civil structures provided that the above limitations are overcome. However, before this system is used with confidence by practitioners, it is essential that it can be effectively operated in field conditions. In light of this, the fibre optics group at the University of New Brunswick has been developing an automated system for field measurement of strain in civil structures, particularly in reinforced concrete. The development of the sensing system hardware and software was the main focus of this thesis. This has been made possible, in part, by observation of the Brillouin spectrum for the case of using very short light pulses (performance to measure strain to an accuracy of 10 muepsilon; and allow the simultaneous measurement of strain and temperature to an accuracy of 204 muepsilon and 3°C are presented. Finally, the results of field measurement of strain on a concrete structure are presented.

Suppression of Brillouin scattering in fibre-optical parametric amplifier by applying temperature control and phase modulation

DEFF Research Database (Denmark)

Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

2009-01-01

An increased gain in a fibre-optical parametric amplifier through suppression of stimulated Brillouin scattering is demonstrated by applying a temperature distribution along the fibre for a fixed phase modulation of the pump. The temperature distribution slightly impacts the gain spectrum....

Angular characteristics of the stimulated-Brillouin-scattering spectrum from a laser plasma with strong acoustic-wave damping

International Nuclear Information System (INIS)

Saikia, P.

1981-01-01

The spectrum of stimulated Brillouin scattering from an inhomogeneous moving laser plasma is analyzed. The damping of acoustic waves and scattered electromagnetic waves is taken into account. Spectra are derived for various scattering angles and for various radii of the laser beam. For all observation angles the center of the spectral line is at an unshifted frequency. As the observation angle increases, the width of the red wing in the spectrum increases. The intensity of the scattered light is very anisotropic

Coherent Rayleigh-Brillouin scattering measurements of bulk viscosity of polar and nonpolar gases, and kinetic theory

NARCIS (Netherlands)

Meijer, A.S.; Wijn, de A.S.; Peters, M.F.E.; Dam, N.J.; Water, van de W.

2010-01-01

We investigate coherent Rayleigh–Brillouin spectroscopy as an efficient process to measure the bulk viscosity of gases at gigahertz frequencies. Scattered spectral distributions are measured using a Fizeau spectrometer. We discuss the statistical error due to the fluctuating mode structure of the

A simple and convenient set-up for high-temperature Brillouin light scattering

International Nuclear Information System (INIS)

Guerette, Michael; Huang Liping

2012-01-01

An emulated platelet geometry (or reflection-induced platelet geometry) is employed to collect photons scattered from both longitudinal and transverse acoustic waves travelling within a bulk transparent sample sitting on a reflective Pt plate. Temperature of the sample was controlled with a Linkam TS1500 optical furnace (maximum temperature of 1500 °C). This simple and convenient set-up allows a full determination of elastic constants of transparent materials in situ as a function of temperature from Brillouin light scattering. Structural information can be gained at the same time by guiding the scattered light into a Raman spectrometer using a flipping mirror or a beam splitter. We will demonstrate the applications of this set-up in transparent inorganic glasses, but it can be easily extended to any other transparent materials, either crystalline or amorphous in nature. (paper)

Simultaneous distributed strain and temperature sensing based on combined Raman–Brillouin scattering using Fabry–Perot lasers

International Nuclear Information System (INIS)

Bolognini, Gabriele; Soto, Marcelo A; Di Pasquale, Fabrizio

2010-01-01

An investigation is performed of the possibility of achieving simultaneous distributed strain and temperature sensing based on hybrid Raman–Brillouin scattering with the use of multi-wavelength optical sources such as common Fabry–Perot (FP) lasers. By employing a self-heterodyne detection scheme based on a multi-wavelength optical local oscillator, the benefits of FP lasers are fully exploited, allowing for high-power Raman intensity measurements and a simultaneous high-accuracy detection of the Brillouin frequency shift parameter for each FP longitudinal mode. Experimental results point out a significant reduction of coherent Rayleigh noise, and highlight the enhanced performance in hybrid Raman–Brillouin sensing when using FP lasers; in particular using standard FP lasers at 1550 nm results in about 12 dB (7 dB) temperature (strain) accuracy improvement at 25 km sensing distance with respect to the use of standard distributed feedback lasers

Guided Acoustic and Optical Waves in Silicon-on-Insulator for Brillouin Scattering and Optomechanics

Science.gov (United States)

2016-08-01

APL PHOTONICS 1, 071301 (2016) Guided acoustic and optical waves in silicon-on- insulator for Brillouin scattering and optomechanics Christopher J...is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator (SOI) material system. Thin...high sound velocity — makes guiding acoustic waves difficult, motivating the use of soft chalcogenide glasses and partial or complete releases (removal

Monitoring the distributed impact wave on a concrete slab due to the traffic based on polarization dependence on stimulated Brillouin scattering

International Nuclear Information System (INIS)

Bao Xiaoyi; Zhang Chunshu; Li Wenhai; Eisa, M; El-Gamal, S; Benmokrane, B

2008-01-01

For the first time to our knowledge, distributed impact waves due to the highway traffic on concrete slabs reinforced with FRP bars are monitored in real time using stimulated Brillouin scattering. The impact wave is caused by the traffic passing on the highway pavement at high speed (>100 km h −1 ), which induced pressure on the concrete slabs, and in turn created a local birefringence change, leading to variation of the local state of polarization change (SOP). The pump and probe waves of the stimulated Brillouin scattering 'see' the SOP change and react with a decrease of the Brillouin gain or loss signal, when the pump and probe waves have the same input polarization state. The frequency difference between the pump and probe waves are locked at the static-strain-related Brillouin frequency. Optical fiber was embedded throughout the concrete pavement continuously reinforced with FRP bars in Highway 40 East, Montréal, Quebec to detect impact waves caused by cars and trucks passing on these pavements at a sampling rate of 10 kHz. A spatial resolution of 2 m was used over a sensing length of 300 m

Stimulated Brillouin scattering during electron gyro-harmonic heating at EISCAT

Directory of Open Access Journals (Sweden)

H. Y. Fu

2015-08-01

Full Text Available Observations of secondary radiation, stimulated electromagnetic emission (SEE, produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF radio waves are considered. The High Frequency Active Auroral Research Program (HAARP facility is capable of generating narrowband SEE in the form of stimulated Brillouin scatter (SBS and stimulated ion Bernstein scatter (SIBS in the SEE spectrum. Such narrowband SEE spectral lines have not been reported using the European Incoherent Scatter (EISCAT heater facility before. This work reports the first EISCAT results of narrowband SEE spectra and compares them to SEE previously observed at HAARP during electron gyro-harmonic heating. An analysis of experimental SEE data shows observations of emission lines within 100 Hz of the pump frequency, interpreted as SBS, during the 2012 July EISCAT campaign. Experimental results indicate that SBS strengthens as the pump frequency approaches the third electron gyro-harmonic. Also, for different heater antenna beam angles, the CUTLASS radar backscatter induced by HF radio pumping is suppressed near electron gyro-harmonics, whereas electron temperature enhancement weakens as measured by EISCAT/UHF radar. The main features of these new narrowband EISCAT observations are generally consistent with previous SBS measurements at HAARP.

Anomalous resonance-radiation energy-transfer rate in a scattering dispersive medium

International Nuclear Information System (INIS)

Shekhtman, V.L.

1992-01-01

This paper describes a generalization of the concept of group velocity as an energy-transfer rate in a dispersive medium with complex refractive index when the polaritons, which are energy carriers, undergo scattering, in contrast to the classical concept of the group velocity of free polaritons (i.e., without scattering in the medium). The concept of delay time from quantum multichannel-scattering, theory is used as the fundamental concept. Based on Maxwell's equations and the new mathematical Φ-function method, a consistent conceptual definition of group velocity in terms of the ratio of the coherent-energy flux density to the coherent-energy density is obtained for the first time, and a critical analysis of the earlier (Brillouin) understanding of energy-transfer rate is given in the light of radiation-trapping theory and the quantum theory of resonance scattering. The role of generalized group velocity is examined for the interpretation of the phenomenon of multiple resonance scattering, or radiation diffusion. The question of causality for the given problem is touched upon; a new relationship is obtained, called the microcausality condition, which limits the anomalous values of group velocity by way of the indeterminacy principle and the relativistic causality principle for macroscopic time intervals directly measurable in experiment, whereby attention is focused on the connection of the given microcausality condition and the well-known Wigner inequality for the time delay of spherical waves. 22 refs

Effect of diffraction on stimulated Brillouin scattering from a single laser hot spot

International Nuclear Information System (INIS)

Eliseev, V.V.; Rozmus, W.; Tikhonchuk, V.T.; Capjack, C.E.

1996-01-01

A single laser hot spot in an underdense plasma is represented as a focused Gaussian laser beam. Stimulated Brillouin scattering (SBS) from such a Gaussian beam with small f/numbers 2-4 has been studied in a three-dimensional slab geometry. It is shown that the SBS reflectivity from a single laser hot spot is much lower than that predicted by a simple three wave coupling model because of the diffraction of the scattered light from the spatially localized ion acoustic wave. SBS gain per one Rayleigh length of the incident laser beam is proposed as a quantitative measure of this effect. Diffraction-limited SBS from a randomized laser beam is also discussed. copyright 1996 American Institute of Physics

Brillouin gain enhancement in nano-scale photonic waveguide

Science.gov (United States)

Nouri Jouybari, Soodabeh

2018-05-01

The enhancement of stimulated Brillouin scattering in nano-scale waveguides has a great contribution in the improvement of the photonic devices technology. The key factors in Brillouin gain are the electrostriction force and radiation pressure generated by optical waves in the waveguide. In this article, we have proposed a new scheme of nano-scale waveguide in which the Brillouin gain is considerably improved compared to the previously-reported schemes. The role of radiation pressure in the Brillouin gain was much higher than the role of the electrostriction force. The Brillouin gain strongly depends on the structural parameters of the waveguide and the maximum value of 12127 W-1 m-1 is obtained for the Brillouin gain.

Remote Water Temperature Measurements Based on Brillouin Scattering with a Frequency Doubled Pulsed Yb:doped Fiber Amplifier

Directory of Open Access Journals (Sweden)

Thomas Walther

2008-09-01

Full Text Available Temperature profiles of the ocean are of interest for weather forecasts, climate studies and oceanography in general. Currently, mostly in situ techniques such as fixed buoys or bathythermographs deliver oceanic temperature profiles. A LIDAR method based on Brillouin scattering is an attractive alternative for remote sensing of such water temperature profiles. It makes it possible to deliver cost-effective on-line data covering an extended region of the ocean. The temperature measurement is based on spontaneous Brillouin scattering in water. In this contribution, we present the first water temperature measurements using a Yb:doped pulsed fiber amplifier. The fiber amplifier is a custom designed device which can be operated in a vibrational environment while emitting narrow bandwidth laser pulses. The device shows promising performance and demonstrates the feasibility of this approach. Furthermore, the current status of the receiver is briefly discussed; it is based on an excited state Faraday anomalous dispersion optical filter.

Analytical study of nonlinear phase shift through stimulated Brillouin scattering in single mode fiber with the pump power recycling technique

International Nuclear Information System (INIS)

Al-Asadi, H A; Mahdi, M A; Bakar, A A A; Adikan, F R Mahamd

2011-01-01

We present a theoretical study of nonlinear phase shift through stimulated Brillouin scattering in single mode optical fiber. Analytical expressions describing the nonlinear phase shift for the pump and Stokes waves in the pump power recycling technique have been derived. The dependence of the nonlinear phase shift on the optical fiber length, the reflectivity of the optical mirror and the frequency detuning coefficient have been analyzed for different input pump power values. We found that with the recycling pump technique, the nonlinear phase shift due to stimulated Brillouin scattering reduced to less than 0.1 rad for 5 km optical fiber length and 0.65 reflectivity of the optical mirror, respectively, at an input pump power equal to 30 mW

Bayesian approach to the analysis of neutron Brillouin scattering data on liquid metals

Science.gov (United States)

De Francesco, A.; Guarini, E.; Bafile, U.; Formisano, F.; Scaccia, L.

2016-08-01

When the dynamics of liquids and disordered systems at mesoscopic level is investigated by means of inelastic scattering (e.g., neutron or x ray), spectra are often characterized by a poor definition of the excitation lines and spectroscopic features in general and one important issue is to establish how many of these lines need to be included in the modeling function and to estimate their parameters. Furthermore, when strongly damped excitations are present, commonly used and widespread fitting algorithms are particularly affected by the choice of initial values of the parameters. An inadequate choice may lead to an inefficient exploration of the parameter space, resulting in the algorithm getting stuck in a local minimum. In this paper, we present a Bayesian approach to the analysis of neutron Brillouin scattering data in which the number of excitation lines is treated as unknown and estimated along with the other model parameters. We propose a joint estimation procedure based on a reversible-jump Markov chain Monte Carlo algorithm, which efficiently explores the parameter space, producing a probabilistic measure to quantify the uncertainty on the number of excitation lines as well as reliable parameter estimates. The method proposed could turn out of great importance in extracting physical information from experimental data, especially when the detection of spectral features is complicated not only because of the properties of the sample, but also because of the limited instrumental resolution and count statistics. The approach is tested on generated data set and then applied to real experimental spectra of neutron Brillouin scattering from a liquid metal, previously analyzed in a more traditional way.

Large On-Chip Amplification in Silicon via Forward Stimulated Brillouin Scattering

Energy Technology Data Exchange (ETDEWEB)

Kittlaus, Eric [Yale Univ., New Haven, CT (United States); Shin, Heedeuk [Yale Univ., New Haven, CT (United States); Rakich, Peter [Yale Univ., New Haven, CT (United States)

2015-10-15

Strong Brillouin coupling has only recently been realized in silicon using a new class of op- tomechanical waveguides that yield both optical and phononic con nement. Despite these major advances, appreciable Brillouin ampli cation has yet to be observed in silicon. Using new membrane- suspended silicon waveguide we report large Brillouin ampli cation for the rst time, reaching levels greater than 5 dB for modest pump powers, and demonstrate a record low (5 mW) threshold for net ampli cation. This work represents a crucial advance necessary to realize high-performance Brillouin lasers and ampli ers in silicon.

Observation of spin-wave dispersion in Nd-Fe-B magnets using neutron Brillouin scattering

International Nuclear Information System (INIS)

Ono, K.; Inami, N.; Saito, K.; Takeichi, Y.; Kawana, D.; Yokoo, T.; Itoh, S.; Yano, M.; Shoji, T.; Manabe, A.; Kato, A.; Kaneko, Y.

2014-01-01

The low-energy spin-wave dispersion in polycrystalline Nd-Fe-B magnets was observed using neutron Brillouin scattering (NBS). Low-energy spin-wave excitations for the lowest acoustic spin-wave mode were clearly observed. From the spin-wave dispersion, we were able to determine the spin-wave stiffness constant D sw (100.0 ± 4.9 meV.Å 2 ) and the exchange stiffness constant A (6.6 ± 0.3 pJ/m)

Interaction between stimulated Brillouin scattering and the filamentation instability in plasmas

International Nuclear Information System (INIS)

Frycz, P.; Rozmus, W.; Samson, J.; Tikhonchuk, V.T.; Rankin, R.

1992-01-01

The set of equations describing Stimulated Brillouin Scattering (SBS) and the Filamentation Instability (FI) are solved numerically for a spatially periodic system. For short systems (a few wavelengths of the incident light) SBS backscatter modes and the filamentation instability are observed as expected but in addition there are some puzzling features. SBS starts after a significant time delay, is localized, and focuses during its evolution. These features disappear for a long (tens of wavelengths) system for which sidescatter modes are dominant. The energy is dispersed among many non-coherent modes in such a system and none of the modes is strong enough to drive filamentation. The analytic explanation of the ''puzzling features'' is given. (Author)

Performance Investigation of Millimeter Wave Generation Reliant on Stimulated Brillouin Scattering

Science.gov (United States)

Tickoo, Sheetal; Gupta, Amit

2018-04-01

In this work, photonic method of generating the millimeter waves has been done based on Brillouin scattering effect in optical fiber. Here different approaches are proposed to get maximum frequency shift in mm-wave region using only pumps, radio signals with Mach-Zehnder modulator. Moreover for generated signal validation, signals modulated and send to both wired and wireless medium in optical domain. It is observed that maximum shift of 300 GHz is realized using 60 GHz input sine wave. Basically a frequency doubler is proposed which double shift of input frequency and provide better SNR. For the future generation network system, the generation of millimeter waves makes them well reliable for the transmission of the data.

Distributed Strain Measurement along a Concrete Beam via Stimulated Brillouin Scattering in Optical Fibers

Directory of Open Access Journals (Sweden)

Romeo Bernini

2011-01-01

Full Text Available The structural strain measurement of tension and compression in a 4 m long concrete beam was demonstrated with a distributed fiber-optic sensor portable system based on Brillouin scattering. Strain measurements provided by the fiber-optic sensor permitted to detect the formation of a crack in the beam resulting from the external applied load. The sensor system is valuable for structural monitoring applications, enabling the long-term performance and health of structures to be efficiently monitored.

Effect of the stimulated Brillouin backscattering on selffocusing threshold

International Nuclear Information System (INIS)

Rubenchik, A.M.; Shapiro, E.G.; Turitsyn, S.K.

1994-03-01

In many physical problems stimulated Brillouin scattering (SBS) and selffocusing are manifested simultaneously. We consider effect of the stimulated Brillouin backscattering (SBS) on self-focusing of laser radiation in plasmas. It was found that the self-focusing may be supressed substantionally by the SBS effect

Observation of narrowband intrinsic spectra of Brillouin dynamic gratings.

Science.gov (United States)

Song, Kwang Yong; Yoon, Hyuk Jin

2010-09-01

We experimentally demonstrate that the reflection spectrum of a Brillouin dynamic grating in a polarization-maintaining fiber can be much narrower than the intrinsic linewidth of the stimulated Brillouin scattering, matching well with the theory of a fiber Bragg grating in terms of the linewidth and the reflectivity. A 3 dB bandwidth as narrow as 10.5 MHz is observed with the Brillouin dynamic grating generated in a 9 m uniform fiber.

Light scattering studies of solids and atomic vapors

International Nuclear Information System (INIS)

Chiang, T.C.

1978-09-01

The general technique of light scattering and luminescence was used to study the properties of a number of material systems. First, multi-phonon resonant Raman scattering up to four phonons in GaSe and one- and two-phonon resonant Raman scattering in the mixed GaS/sub x/Se/sub 1-x/ crystals with x 2 is reported. The result is used to determine the position of the direct gap of HfS 2 . Third, the first observation of the π-polarized one-magnon luminescence sideband of the 4 T/sub lg/ ( 4 G) → 6 A/sub lg/( 6 S) excitonic transition in antiferromagnetic MnF 2 is presented. An effective temperature of the crystal is deduced from the simultaneously observed anti-Stokes sideband emission. Multi-magnon ( 2 , KMnF 2 , and RbMnF 3 using pulsed excitation and detection. A simple model based on two-ion local exchange is proposed to explain the results qualitatively. Fourth, the first observation of two-magnon resonant Raman scattering in MnF 2 around the magnon sidebands is reported. A simple theoretical description explains the experimental observations. Fifth, a detailed theory of exciton-exciton interaction in MnF 2 is developed to explain and to predict the experimental results on two-exciton absorption, high level excitation, and exciton--exciton scattering. Sixth, Brillouin scattering was used to obtain the five independent elastic constants of the layered compound GaSe. The results show clear elastic anisotropy of the crystal. Resonant Brillouin scattering near the absorption edge was also studied, but no resonant enhancement was found. Seventh, two-photon parametric scattering in sodium vapor was studied. Phase matching angles and scattering cross sections are calculated for a given set of experimental conditions

LASERS: Stimulated emission in a solid-state ring laser with a stimulated Brillouin scattering mirror

Science.gov (United States)

Barashkov, M. S.; Bel'dyugin, Igor'M.; Zolotarev, M. V.; Krymskiĭ, M. I.; Oshkin, S. P.; Umnov, A. F.; Kharchenko, M. A.

1990-06-01

The results are presented of an experimental investigation of a solid-state ring laser with a stimulated Brillouin scattering mirror and lasing initiated by a series of ~ 200-300 ns pulses of 1.06 μm wavelength. It is shown that this laser may be useful for the development of a source with radiation parameters controlled by an external signal (energy, transverse and time structure) and also of a low-threshold mirror for phase self-conjugation of radiation.

Stimulated Brillouin processes in crystals and glasses

International Nuclear Information System (INIS)

Faris, G.W.; Hickman, A.P.

1992-02-01

The basic physics and material properties needed to describe and predict the Brillouin gain for a variety of materials have been investigated. Lawrence Livermore National Laboratory (LLNL) has identified transverse stimulated Brillouin scattering (SBS) as an important limiting mechanism in high power laser fusion systems. At sufficiently high laser intensities, SBS drives acoustic vibrations that can damage optical components. SRI has performed measurements and developed the corresponding theory for stimulated Brillouin gain spectroscopy in anisotropic crystals. Absolute Brillouin steady-state gain coefficients, linewidths, and frequency shifts have been determined at 532 nm for a number of optical materials of interest to LLNL. This knowledge can be used to select optical materials and devise suppression schemes that will allow much higher laser fluences to be used in laser fusion

Brillouin micro-spectroscopy through aberrations via sensorless adaptive optics

Science.gov (United States)

Edrei, Eitan; Scarcelli, Giuliano

2018-04-01

Brillouin spectroscopy is a powerful optical technique for non-contact viscoelastic characterizations which has recently found applications in three-dimensional mapping of biological samples. Brillouin spectroscopy performances are rapidly degraded by optical aberrations and have therefore been limited to homogenous transparent samples. In this work, we developed an adaptive optics (AO) configuration designed for Brillouin scattering spectroscopy to engineer the incident wavefront and correct for aberrations. Our configuration does not require direct wavefront sensing and the injection of a "guide-star"; hence, it can be implemented without the need for sample pre-treatment. We used our AO-Brillouin spectrometer in aberrated phantoms and biological samples and obtained improved precision and resolution of Brillouin spectral analysis; we demonstrated 2.5-fold enhancement in Brillouin signal strength and 1.4-fold improvement in axial resolution because of the correction of optical aberrations.

The electromagnetic Brillouin precursor in one-dimensional photonic crystals

NARCIS (Netherlands)

Uitham, R.; Hoenders, B. J.

2008-01-01

We have calculated the electromagnetic Brillouin precursor that arises in a one-dimensional photonic crystal that consists of two homogeneous slabs which each have a single electron resonance. This forerunner is compared with the Brillouin precursor that arises in a homogeneous double-electron

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Threshold and maximum power evolution of stimulated Brillouin scattering and Rayleigh backscattering in a single mode fiber segment

International Nuclear Information System (INIS)

Sanchez-Lara, R; Alvarez-Chavez, J A; Mendez-Martinez, F; De la Cruz-May, L; Perez-Sanchez, G G

2015-01-01

The behavior of stimulated Brillouin scattering (SBS) and Rayleigh backscattering phenomena, which limit the forward transmission power in modern, ultra-long haul optical communication systems such as dense wavelength division multiplexing systems is analyzed via simulation and experimental investigation of threshold and maximum power. Evolution of SBS, Rayleigh scattering and forward powers are experimentally investigated with a 25 km segment of single mode fiber. Also, a simple algorithm to predict the generation of SBS is proposed where two criteria of power thresholds was used for comparison with experimental data. (paper)

Rayleigh-Brillouin scattering in SF6 in the kinetic regime

Science.gov (United States)

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

2017-02-01

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

Laser-induced damage of fused silica optics at 355 nm due to backward stimulated Brillouin scattering: experimental and theoretical results.

Science.gov (United States)

Lamaignère, Laurent; Gaudfrin, Kévin; Donval, Thierry; Natoli, Jeanyves; Sajer, Jean-Michel; Penninckx, Denis; Courchinoux, Roger; Diaz, Romain

2018-04-30

Forward pump pulses with nanosecond duration are able to generate an acoustic wave via electrostriction through a few centimeters of bulk silica. Part of the incident energy is then scattered back on this sound wave, creating a backward Stokes pulse. This phenomenon known as stimulated Brillouin scattering (SBS) might induce first energy-loss, variable change of the temporal waveform depending on the location in the spatial profile making accurate metrology impossible, and moreover it might also initiate front surface damage making the optics unusable. Experiments performed on thick fused silica optics at 355 nm with single longitudinal mode pulses allowed us to detect, observe and quantify these backward pulses. Experimental results are first compared to theoretical calculations in order to strengthen our confidence in metrology. On this basis a phase-modulator has been implemented on the continuous-wave seeders of the lasers leading to pulses with a wide spectrum that suppress SBS and do not exhibit temporal overshoots that also reduce Kerr effects. The developed set-ups are used to check the reduction of the backward stimulated Brillouin scattering and they allow measuring with accuracy the rear surface damage of thick fused silica optics.

Stimulated Brillouin scattering experiments

International Nuclear Information System (INIS)

Slater, D.C.; Berger, R.L.; Busch, G.; Kinzer, C.M.; Mayer, F.J.; Powers, L.V.; Tanner, D.J.

1981-01-01

This report describes two experiments in which SBS would be expected to play an important role. In the first experiment, we find a clear signature of the Brillouin backscatter of a short (100 psec) pulse from a long (approx. 50 μm) gradient length gas target plasma. The second experiment used much longer (approx. 1 nsec) pulses on spherical glass shell targets. These experiments were done with both narrow ( 30A) bandwidth laser light. Using one-dimensional, spherically symmetric fluid simulations, we have attempted to model many of the laser-plasma interaction processes which combine to determine the amount of absorbed energy in the long-pulse experiments. These simulations indicate that modest laser bandwidths are successful in reducing the level of SBS at the irradiances ( 15 W/cm 2 ) used in these experiments

Brillouin microscopy: assessing ocular tissue biomechanics.

Science.gov (United States)

Yun, Seok Hyun; Chernyak, Dimitri

2018-07-01

Assessment of corneal biomechanics has been an unmet clinical need in ophthalmology for many years. Many researchers and clinicians have identified corneal biomechanics as source of variability in refractive procedures and one of the main factors in keratoconus. However, it has been difficult to accurately characterize corneal biomechanics in patients. The recent development of Brillouin light scattering microscopy heightens the promise of bringing biomechanics into the clinic. The aim of this review is to overview the progress and discuss prospective applications of this new technology. Brillouin microscopy uses a low-power near-infrared laser beam to determine longitudinal modulus or mechanical compressibility of tissue by analyzing the return signal spectrum. Human clinical studies have demonstrated significant difference in the elastic properties of normal corneas versus corneas diagnosed with mild and severe keratoconus. Clinical data have also shown biomechanical changes after corneal cross-linking treatment of keratoconus patients. Brillouin measurements of the crystalline lens and sclera have also been demonstrated. Brillouin microscopy is a promising technology under commercial development at present. The technique enables physicians to characterize the biomechanical properties of ocular tissues.

Detrimental Effect Elimination of Laser Frequency Instability in Brillouin Optical Time Domain Reflectometer by Using Self-Heterodyne Detection

Directory of Open Access Journals (Sweden)

Yongqian Li

2017-03-01

Full Text Available A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra from fibers with different lengths measured by heterodyne detection, the maximum usable pulse width immune to laser frequency instability is obtained to be about 4 µs in a self-heterodyne detection Brillouin optical time domain reflectometer (BOTDR system using a broad-band laser with low frequency stability. Applying the self-heterodyne detection of Rayleigh and Brillouin scattering in BOTDR system, we successfully demonstrate that the detrimental effect of laser frequency instability on Brillouin signals can be eliminated effectively. Employing the broad-band laser modulated by a 130-ns wide pulse driven electro-optic modulator, the observed maximum errors in temperatures measured by the local heterodyne and self-heterodyne detection BOTDR systems are 7.9 °C and 1.2 °C, respectively.

Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

Science.gov (United States)

Massey, Steven M; Spring, Justin B; Russell, Timothy H

2008-07-21

Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

Surface acoustic waves and elastic constants of InN epilayers determined by Brillouin scattering

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Rioboo, R.J.; Prieto, C. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid (Spain); Cusco, R.; Domenech-Amador, N.; Artus, L. [Institut Jaume Almera, Consell Superior d' Investigacions Cientifiques (CSIC), Lluis Sole i Sabaris s.n., Barcelona, Catalonia (Spain); Yamaguchi, T.; Nanishi, Y. [Faculty of Science and Engineering, Ritsumeikan University, Noji-Higashi, Kusatsu, Shiga (Japan)

2012-06-15

The surface acoustic wave velocity in InN has been experimentally determined by means of Brillouin scattering experiments on c - and m -face epilayers. From simulations based on the Green's function formalism we determine the shear elastic constants c{sub 66} and c{sub 44} and propose a complete set of elastic constants for wurtzite InN. The analysis of the sagittal and azimuthal dependence of the surface acoustic wave velocity indicates a slightly different elastic behavior of the m -face sample that basically affects the c{sub 44} elastic constant. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

A Brillouin scattering study of the effect of chemical passivation on the elastic properties of porous silicon

Science.gov (United States)

Fan, H. J.; Kuok, M. H.; Ng, S. C.; Boukherroub, R.; Lockwood, D. J.

2002-07-01

Brillouin scattering has been performed to probe acoustic waves in porous silicon films that have been chemically modified with either 1-decene, decyl aldehyde, undecylenic acid, or ethyl undecylenate. The shift in the frequencies of acoustic modes in the passivated porous silicon samples, relative to those in freshly prepared porous silicon, is different for different chemical modifiers. The magnitude of the frequency shift is qualitatively correlated with the change, caused by the passivation, in the average densities and elastic constants of the samples.

Transition from hydrodynamic to fast sound in a He-Ne mixture a neutron Brillouin scattering experiment

CERN Document Server

Bafile, U; Barocchi, F; Sampoli, M

2002-01-01

The presence of a fast-sound mode in the microscopic dynamics of the rare-gas mixture He-Ne, predicted by theoretical studies and molecular-dynamics simulations, was demonstrated by an inelastic neutron scattering experiment. In order to study the transition between the fast and the normal acoustic modes in the hydrodynamic regime, k values lower by about one order of magnitude than in the usual experiments have to be probed. We describe here the results of the first neutron Brillouin scattering experiment performed with this purpose on the same system already investigated at larger k. The results of both experiments, together with those of a new molecular-dynamics simulation, provide a complete and consistent description, still missing so far, of the onset of fast-sound propagation in a binary mixture. (orig.)

Broadband multi-wavelength Brillouin lasers with an operating wavelength range of 1500–1600 nm generated by four-wave mixing in a dual wavelength Brillouin fiber laser cavity

Science.gov (United States)

Li, Q.; Jia, Z. X.; Weng, H. Z.; Li, Z. R.; Yang, Y. D.; Xiao, J. L.; Chen, S. W.; Huang, Y. Z.; Qin, W. P.; Qin, G. S.

2018-05-01

We demonstrate broadband multi-wavelength Brillouin lasers with an operating wavelength range of 1500–1600 nm and a frequency separation of ~9.28 GHz generated by four-wave mixing in a dual wavelength Brillouin fiber laser cavity. By using one continuous-wave laser as the pump source, multi-wavelength Brillouin lasers with an operating wavelength range of 1554–1574 nm were generated via cascaded Brillouin scattering and four-wave mixing. Interestingly, when pumped by two continuous-wave lasers with an appropriate frequency separation, the operating wavelength range of the multi-wavelength Brillouin lasers was increased to 1500–1600 nm due to cavity-enhanced cascaded four-wave mixing among the frequency components generated by two pump lasers in the dual wavelength Brillouin laser cavity.

Brillouin scattering, DSC, dielectric and X-ray diffraction studies of phase transitions in antiferroelectric PbHfO{sub 3}:Sn

Energy Technology Data Exchange (ETDEWEB)

Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Kim, Tae Hyun [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Gągor, Anna [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Jankowska-Sumara, Irena [Institute of Physics, Pedagogical University, ul. Podchorążych 2, 30-084 Kraków (Poland); Majchrowski, Andrzej [Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Kojima, Seiji [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

2015-02-15

Highlights: • Phase transition mechanisms were studied in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3.} • Acoustic phonons showed anomalies at 472 and 426 K due to phase transitions. • Brillouin data showed evidence for presence of polar clusters in paraelectric phase. • An order-disorder mechanism of the PE to AFE2 transition was proved. - Abstract: Specific heat, dielectric, powder X-ray diffraction and Brillouin scattering studies of phase transitions in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3} crystal were performed. The specific heat data revealed clear anomalies at T{sub 1} = 473.5 and T{sub 2} = 426.3 K on cooling, which could be attributed to onset of first order phase transitions from the paraelectric (PE) phase to an intermediate antiferroelectric phase (AFE2) and the AFE2 phase to another antiferroelectric phase (AFE1), respectively. The estimated entropy changes at T{sub 1} and T{sub 2} pointed to mainly an order-disorder and displacive character of these transitions, respectively. X-ray diffraction data showed a complex superstructure of the intermediate phase with a = 11.895(6) Å, b = 11.936(4) Å, c = 8.223(3) Å at 453 K. Brillouin studies revealed pronounced softening of longitudinal acoustic (LA) mode in the PE phase associated with its broadening. The broadening and softening exhibited maximum values at T{sub 1}. Additional acoustic anomalies, that is, abrupt frequency shifts for LA and transverse acoustic (TA) modes were also observed at T{sub 2}. Brillouin scattering data also showed presence of a broad central peak (CP) that exhibited highest intensity at T{sub 1}. The observed temperature dependences of acoustic modes and CP indicate order-disorder character of the FE to AFE2 phase transition and importance of polar precursor clusters in the PE phase. The obtained data also suggest that the intermediate antiferroelectric phases in Sn{sup 4+} doped PbHfO{sub 3} and PbZrO{sub 3} may have very similar structures

Brillouin suppression in a fiber optical parametric amplifier by combining temperature distribution and phase modulation

DEFF Research Database (Denmark)

Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

2008-01-01

We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation.......We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation....

High-resolution stimulated Brillouin gain spectroscopy in glasses and crystals

International Nuclear Information System (INIS)

Faris, G.W.; Jusinski, L.E.; Hickman, A.P.

1993-01-01

Theory and measurements are presented for stimulated Brillouin gain spectroscopy in anisotropic media. The coupling between arbitrary pump and Stokes waves and the corresponding acoustic wave is formulated in terms of the elastic displacement vector and the photoelastic tensor. A propagation equation that fully includes transient effects is obtained for the Stokes wave. In the limit of small-signal gains this propagation equation can be solved analytically, yielding expressions that relate experimentally accessible quantities to material properties. Absolute Brillouin steady-state gain coefficients, linewidths, and frequency shifts are thereby determined in a number of optical materials at 532 nm. The Brillouin gain coefficient for fused silica is measured by three techniques, providing the reference for absolute gain measurements. Quantitative agreement is found between theory and experiment for transient effects on stimulated Brillouin scattering

Brillouin spectroscopy as a new method of screening for increased CSF total protein during bacterial meningitis.

Science.gov (United States)

Steelman, Zachary; Meng, Zhaokai; Traverso, Andrew J; Yakovlev, Vladislav V

2015-05-01

Bacterial meningitis is a disease of pronounced clinical significance, especially in the developing world. Immediate treatment with antibiotics is essential, and no single test can provide a conclusive diagnosis. It is well established that elevated total protein in cerebrospinal fluid (CSF) is associated with bacterial meningitis. Brillouin spectroscopy is a widely used optical technique for noninvasive determination of the elastic moduli of materials. We found that elevated protein levels in CSF alter the fluid elasticity sufficiently to be measurable by Brillouin spectroscopy, with model healthy and diseased fluids distinguishable to marked significance (P = 0.014), which increases with sample concentration by dialysis. Typical raw output of a 2-stage VIPA Brillouin spectrometer: inelastically scattered Brillouin peaks (arrows) and elastically scattered incident radiation (center cross). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-crystal Brillouin spectroscopy with CO{sub 2} laser heating and variable q

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jin S.; Bass, Jay D. [Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Zhu, Gaohua [Materials Research Department, Toyota Research Institute of North America, Ann Arbor, Michigan 48105 (United States)

2015-06-15

We describe a Brillouin spectroscopy system integrated with CO{sub 2} laser-heating and Raman spectroscopic capabilities. Temperature is determined by measurements of the grey-body thermal radiation emitted by the hot sample, with the system response calibrated relative to a standard tungsten ribbon lamp. High-pressure laser-heating Brillouin scattering measurements of acoustic velocities on liquid water and ice compressed in a diamond-anvil cell were performed at temperatures up to 2500 ± 150 K at high pressure. Single-crystal laser-heating Brillouin measurements were made on the (111) plane of San Carlos olivine at ∼13 GPa, 1300 ± 200 K. The pressure as measured by ruby fluorescence is shown to be within ±0.5 GPa of the pressure on the olivine sample during laser heating when KCl and KBr are used as pressure-transmitting media. In addition, the system is designed for continuously variable scattering angles from forward scattering (near 0° scattering angle) up to near back scattering (∼141°). This novel setup allows us to probe a wide range of wave vectors q for investigation of phonon dispersion on, for example, crystals with large unit cells (on the scale of hundreds of nm)

Light absorption and scattering mechanisms in laser fusion plasmas

International Nuclear Information System (INIS)

Barnes, C.; Estabrook, K.G.; Kruer, W.L.; Langdon, A.B.; Lasinski, B.F.; Max, C.E.; Randall, C.; Thomson, J.J.

1977-01-01

The picture of laser light absorption and scattering which is emerging from theory and computer simulation studies of laser-plasma interactions is described. On the subject of absorption, we discuss theoretical and experimental evidence that resonance absorption in a steepened density profile is a dominant absorption mechanism. Recent work also indicates the presence of critical surface ripples, which we study using two and three dimensional computer simulations. Predictions of hot electron spectra due to resonance absorption are described, as are effects of plasma outflow. We then discuss two regimes where stimulated scattering may occur. Brillouin scattering is expected in the underdense target blow-off, for long laser pulses, and is limited by ion heating. Raman scattering in the background gas of a reactor target chamber is predicted to be at most a 10 percent effect for 1 μm lasers

Brillouin scattering on TbAsO4 and GdVO4

International Nuclear Information System (INIS)

Wehrle, H.

1975-01-01

Using a two-pass interferometer the set of elastic constants in TbAsO 4 was determined. On the basis of these constants the Debye temperature was evaluated for T→0. The crystallographic phase transition could not be demonstrated in either case (TbAsO 4 and TmAsO 4 ) because of small Brillouin-line intensity in the low-temperature region. The frequency shifts of the Brillouin lines detected in the case of GdVO 4 show an increase of 5% for the temperature change from room temperature to helium temperature. Assuming this dependence for TbAsO 4 , too, the Debye temperature is changed by 5%. (HPOE) [de

Unusual features of long-range density fluctuations in glass-forming organic liquids: A Rayleigh and Rayleigh-Brillouin light scattering study

International Nuclear Information System (INIS)

Patkowski, A.; Fischer, E. W.; Steffen, W.; Glaser, H.; Baumann, M.; Ruths, T.; Meier, G.

2001-01-01

A new feature of glass-forming liquids, i.e., long-range density fluctuations of the order of 100 nm, has been extensively characterized by means of static light scattering, photon correlation spectroscopy and Rayleigh-Brillouin spectroscopy in orthoterphenyl (OTP) and 1,1-di(4 # prime#-methoxy-5 # prime#methyl-phenyl)-cyclohexane (BMMPC). These long-range density fluctuations result in the following unusual features observed in a light scattering experiment, which are not described by the existing theories: (i) strong q-dependent isotropic excess Rayleigh intensity, (ii) additional slow component in the polarized photon correlation function, and (iii) high Landau-Placzek ratio. These unusual features are equilibrium properties of the glass-forming liquids and depend only on temperature, provided that the sample has been equilibrated long enough. The temperature-dependent equilibration times were measured for BMMPC and are about 11 orders of magnitude longer than the α process. It was found that the glass-forming liquid OTP may occur in two states: with and without long-range density fluctuations ('clusters'). We have characterized the two states by static and dynamic light scattering in the temperature range from T g to T g +200 K. The relaxation times of the α process as well as the parameters of the Brillouin line are identical in both OTP with and without clusters. The α process (density fluctuations) in OTP was characterized by measuring either the polarized (VV) or depolarized (VH) correlation function, which are practically identical and q-independent. This feature, which is commonly observed in glass-forming liquids, is not fully explained by the existing theories

Systematic study on nuclear resonant scattering

International Nuclear Information System (INIS)

Suarez, A.A.; Freitas, M.L.

1974-01-01

New resonant scattering effect of thermal neutron capture gamma rays from Ti and Fe on Sb, Cu, Se and Ce target were observed. These results together with those published by other authors are summarized and discussed in terms of a possible systematic search for new resonant scattering effects

Brillouin light scattering study of spin waves in NiFe/Co exchange spring bilayer films

Energy Technology Data Exchange (ETDEWEB)

Haldar, Arabinda; Banerjee, Chandrima; Laha, Pinaki; Barman, Anjan, E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India)

2014-04-07

Spin waves are investigated in Permalloy(Ni{sub 80}Fe{sub 20})/Cobalt(Co) exchange spring bilayer thin films using Brillouin light scattering (BLS) experiment. The magnetic hysteresis loops measured by magneto-optical Kerr effect show a monotonic decrease in coercivity of the bilayer films with increasing Py thickness. BLS study shows two distinct modes, which are modelled as Damon-Eshbach and perpendicular standing wave modes. Linewidths of the frequency peaks are found to increase significantly with decreasing Py layer thickness. Interfacial roughness causes to fluctuate exchange coupling at the nanoscale regimes and the effect is stronger for thinner Py films. A quantitative analysis of the magnon linewidths shows the presence of strong local exchange coupling field which is much larger compared to macroscopic exchange field.

Self-pulsation threshold of Raman amplified Brillouin fiber cavities

DEFF Research Database (Denmark)

Ott, Johan Raunkjær; Pedersen, Martin Erland Vestergaard; Rottwitt, Karsten

2009-01-01

An implicit equation for the oscillation threshold of stimulated Brillouin scattering from Raman amplified signals in fibers with external feedback is derived under the assumption of no depletion. This is compared to numerical investigations of Raman amplification schemes showing good agreement...

Quantum-Chemical Calculation and Visualization of the Vibrational Modes of Graphene in Different Points of the Brillouin Zone.

Science.gov (United States)

Lebedieva, Tetiana; Gubanov, Victor; Dovbeshko, Galyna; Pidhirnyi, Denys

2015-12-01

Different notations of graphene irreducible representations and optical modes could be found in the literature. The goals of this paper are to identify the correspondence between available notations, to calculate the optical modes of graphene in different points of the Brillouin zone, and to compare them with experimental data obtained by Raman and coherent anti-Stokes Raman scattering (CARS) spectroscopy. The mechanism of the resonance enhancement of vibration modes of the molecules adsorbed on graphene in CARS experiments is proposed. The possibility of appearance of the discrete breathing modes is discussed.

A Brillouin scattering study of La0.77Ca0.23MnO3 across the metal-insulator transition

International Nuclear Information System (INIS)

Seikh, Md Motin; Narayana, Chandrabhas; Sudheendra, L; Sood, A K; Rao, C N R

2004-01-01

Temperature-dependent Brillouin scattering studies have been carried out on La 0.77 Ca 0.23 MnO 3 across the paramagnetic insulator-ferromagnetic metal (I-M) transition (T C ∼ 230 K). The spectra show modes corresponding to a surface Rayleigh wave (SRW) and a high velocity pseudo-surface wave (HVPSAW) along with bulk acoustic waves (B1 and B2). The Brillouin shifts associated with the SRW and HVPSAW increase, whereas the B1 and B2 frequencies decrease, below T C . The temperature dependence of the SRW and HVPSAW modes is related to the increase in the elastic constant C 11 across the I-M transition. The decrease in frequency across the I-M transition of the bulk modes is understood to be due to enhanced self-energy corrections as a result of increased magnon-phonon interaction across the I-M transition. Correspondingly, these modes show a large increase in the full width at half maximum (FWHM) as the temperature decreases. We also observe a central peak whose width is maximum at T C

Martensitic phase transition in Cu–14%Al–4%Ni shape memory alloys studied by Brillouin light scattering

International Nuclear Information System (INIS)

Graczykowski, B; Mielcarek, S; Mroz, B; Breczewski, T; No, M L; San-Juan, J

2013-01-01

The paper presents the influence of the martensitic phase transition on hypersonic thermally excited surface acoustic waves propagating in Cu–14%Al–4%Ni (wt%) shape memory alloy. Non-destructive and non-contact testing using Brillouin light scattering spectroscopy permitted determination of the elastic constants of austenite versus temperature. Experimental results obtained for martensite were interpreted using the proposed model of the cubic to orthorhombic martensitic phase transition based on the Landau model of a first-order phase transition. Additionally we adopted the approximation of the domain structure of martensite by a polycrystalline sample using the Voigt–Reuss–Hill procedure of averaging the elastic constants. (paper)

Pump spectral linewidth influence on stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) and self-termination behavior of SRS in liquids

Energy Technology Data Exchange (ETDEWEB)

He, Guang S.; Kuzmin, Andrey; Prasad, Paras N. [The Institute for Lasers, Photonics and Biophotonics, State University of New York, Buffalo, NY (United States)

2016-12-15

The threshold, temporal behavior, and conversion efficiency of stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SBS) in three liquids (benzene, hexane, and dimethyl sulfoxide) and two crystals (calcite and barium nitrate) have been investigated under three largely different spectral linewidth conditions. Pumped with 532-nm and nanosecond duration laser pulses of ≤ 0.01 cm{sup -1} linewidth, only SBS can be generated in all tested liquids with a high nonlinear reflectivity. However when the pump spectral linewidth is ∝0.07 cm{sup -1} or ∝0.8 cm{sup -1}, both SBS and SRS can be observed in benzene while only SRS can be generated in dimethyl sulfoxide; in all these cases SRS is the dominant contribution to the stimulated scattering but the efficiency values are drastically decreased due to the self-termination behavior of SRS in liquids, which arises from the thermal self-defocusing of both pump beam and SRS beam owing to Stokes-shift related opto-heating effect. In contrast, for SRS process in the two crystals, the thermal self-defocusing influence is negligible benefitting from their much greater thermal conductivity, and a higher conversion efficiency of SRS generation can be retained under all three pump conditions. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Angle-resolved spin wave band diagrams of square antidot lattices studied by Brillouin light scattering

Energy Technology Data Exchange (ETDEWEB)

Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del Consiglio Nazionale delle Ricerche (IOM-CNR), Sede di Perugia, c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, I-06123 Perugia (Italy); Montoncello, F.; Giovannini, L. [Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via G. Saragat 1, I-44122 Ferrara (Italy); Madami, M.; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06123 Perugia (Italy); Ding, J.; Adeyeye, A. O. [Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

2015-06-29

The Brillouin light scattering technique has been exploited to study the angle-resolved spin wave band diagrams of squared Permalloy antidot lattice. Frequency dispersion of spin waves has been measured for a set of fixed wave vector magnitudes, while varying the wave vector in-plane orientation with respect to the applied magnetic field. The magnonic band gap between the two most dispersive modes exhibits a minimum value at an angular position, which exclusively depends on the product between the selected wave vector magnitude and the lattice constant of the array. The experimental data are in very good agreement with predictions obtained by dynamical matrix method calculations. The presented results are relevant for magnonic devices where the antidot lattice, acting as a diffraction grating, is exploited to achieve multidirectional spin wave emission.

Method for pulse control in a laser including a stimulated brillouin scattering mirror system

Science.gov (United States)

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2007-10-23

A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

Wavelength dependence of the Brillouin spectral width of boron doped germanosilicate optical fibers.

Science.gov (United States)

Law, Pi-Cheng; Dragic, Peter D

2010-08-30

Boron co-doped germanosilicate fibers are investigated via the Brillouin light scattering technique using two wavelengths, 1534 nm and 1064 nm. Several fibers are investigated, including four drawn from the same preform but at different draw temperatures. The Stokes' shifts and the Brillouin spectral widths are found to increase with increasing fiber draw temperature. A frequency-squared law has adequately described the wavelength dependence of the Brillouin spectral width of conventional Ge-doped fibers. However, it is found that unlike conventional Ge-doped fibers these fibers do not follow the frequency-squared law. This is explained through a frequency-dependent dynamic viscosity that modifies this law.

Anomalous and resonance small-angle scattering

International Nuclear Information System (INIS)

Epperson, J.E.; Thiyagarajan, P.

1988-01-01

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 consideration of 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 analog 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 scattering are discussed. (orig.)

Resonant neutrino scattering: An impossible experiment?

International Nuclear Information System (INIS)

Suzuki, D.; Sumikama, T.; Ogura, M.; Mittig, W.; Shiraki, A.; Ichikawa, Y.; Kimura, H.; Otsu, H.; Sakurai, H.; Nakai, Y.; Hussein, M.S.

2010-01-01

The experimental feasibility was investigated for the resonant scattering of monoenergetic neutrinos emitted in the two-body β decay. A simple general formula shows that the resonance cross section can be as large as of the order of 10 -17 cm 2 . The Moessbauer setup using a solid crystal was examined with a focus on the electronic structure of the emitter and the absorber. Based on realistic calculations, we show that interactions of valence electrons in the solid lead to a level broadening of the atomic ground state, which considerably suppresses the resonant scattering of neutrinos.

Influence of KF substitution on the ferroelectric phase transition of lead titanate single crystals studied by Brillouin light scattering

Directory of Open Access Journals (Sweden)

Seonhyeop Shin

2015-06-01

Full Text Available The elastic properties of KF-substituted perovskite lead titanate (PbTiO3 were investigated by dielectric measurements and Brillouin light scattering. The ferroelectric phase transition occurred at substantially lower temperature due to KF substitution, which was attributed to the modification of the covalency in Pb–O and Ti–O bonds. The longitudinal acoustic (LA mode of KF-substituted PbTiO3 showed a frequency softening in the paraelectric phase, which was accompanied by increasing acoustic damping. This indicated that polarization fluctuations responsible for the acoustic anomalies were enhanced by KF substitution.

Standard deviation index for stimulated Brillouin scattering suppression with different homogeneities.

Science.gov (United States)

Ran, Yang; Su, Rongtao; Ma, Pengfei; Wang, Xiaolin; Zhou, Pu; Si, Lei

2016-05-10

We present a new quantitative index of standard deviation to measure the homogeneity of spectral lines in a fiber amplifier system so as to find the relation between the stimulated Brillouin scattering (SBS) threshold and the homogeneity of the corresponding spectral lines. A theoretical model is built and a simulation framework has been established to estimate the SBS threshold when input spectra with different homogeneities are set. In our experiment, by setting the phase modulation voltage to a constant value and the modulation frequency to different values, spectral lines with different homogeneities can be obtained. The experimental results show that the SBS threshold increases negatively with the standard deviation of the modulated spectrum, which is in good agreement with the theoretical results. When the phase modulation voltage is confined to 10 V and the modulation frequency is set to 80 MHz, the standard deviation of the modulated spectrum equals 0.0051, which is the lowest value in our experiment. Thus, at this time, the highest SBS threshold has been achieved. This standard deviation can be a good quantitative index in evaluating the power scaling potential in a fiber amplifier system, which is also a design guideline in suppressing the SBS to a better degree.

Raman scattering in a nearly resonant density ripple

International Nuclear Information System (INIS)

Barr, H.C.; Chen, F.F.

1987-01-01

Stimulated Raman scattering of light waves by an underdense plasma is affected by the presence of a density ripple caused by a simultaneously occurring stimulated Brillouin instability. The problem is treated kinetically for the particularly interesting case where the ripple has nearly the same wavelength as the plasma wave. The ripple is found to reduce the growth rate of the usual Raman instability but allows other decay modes to occur. Numerical results for the frequencies, growth rates, and k spectra of these modes are obtained. A physical explanation is given for a baffling result of the calculation. The physical picture is also of interest to particle acceleration by plasma waves

Particle trapping in stimulated scattering processes

International Nuclear Information System (INIS)

Karttunen, S.J.; Heikkinen, J.A.

1981-01-01

Particle trapping effects on stimulated Brillouin and Raman scattering are investigated. A time and space dependent model assumes a Maxwellian plasma which is taken to be homogeneous in the interaction region. Ion trapping has a rather weak effect on stimulated Brillouin scattering and large reflectivities are obtained even in strong trapping regime. Stimulated Raman scattering is considerably reduced by electron trapping. Typically 15-20 times larger laser intensities are required to obtain same reflectivity levels than without trapping. (author)

Resonant x-ray Raman scattering from atoms and molecules

International Nuclear Information System (INIS)

Cowan, P.L.

1992-01-01

Inelastic x-ray scattering and elastic x-ray scattering are fundamentally related processes. When the x-ray photon energy is near the ionization threshold for an inner shell, the inelastic channel is dominated by resonant x-ray Raman scattering. Studies of this emission not only illuminate the resonant scattering process in general, they also point to new opportunities for spectral studies of electronic structure using x-rays. Atoms in the form of a free gas provide an ideal target for testing the current theoretical understanding of resonant x-ray Raman scattering. In addition, x-ray scattering from molecular gases demonstrates the effect of bonding symmetry on the polarization and angular distribution of the scattered x-rays. Comparisons of experimental data with theory demonstrate both the successes and limitations of simple, single-electron interpretations of the scattering process

Resonant inelastic x-ray scattering studies of magnons and bimagnons in the lightly doped cuprate La2 -xSrxCuO4

Science.gov (United States)

Chaix, L.; Huang, E. W.; Gerber, S.; Lu, X.; Jia, C.; Huang, Y.; McNally, D. E.; Wang, Y.; Vernay, F. H.; Keren, A.; Shi, M.; Moritz, B.; Shen, Z.-X.; Schmitt, T.; Devereaux, T. P.; Lee, W.-S.

2018-04-01

We investigated the doping dependence of magnetic excitations in the lightly doped cuprate La2 -xSrxCuO4 via combined studies of resonant inelastic x-ray scattering (RIXS) at the Cu L3 edge and theoretical calculations. With increasing doping, the magnon dispersion is found to be essentially unchanged, but the spectral width broadens and the spectral weight varies differently at different momenta. Near the Brillouin zone center, we directly observe bimagnon excitations that possess the same energy scale and doping dependence as previously observed by Raman spectroscopy. They disperse weakly in energy-momentum space, and they are consistent with a bimagnon dispersion that is renormalized by the magnon-magnon interaction at the zone center.

KrF laser amplifier with phase-conjugate Brillouin retroreflectors.

Science.gov (United States)

Gower, M C

1982-09-01

We have demonstrated the use of phase-conjugate stimulated Brillouin scattering mirrors to produce high-quality, short-pulse KrF laser beams from angular multiplexed and regenerative amplifiers. The mirror was also shown to isolate systems optically from amplifier spontaneous emission. Automatic alignment of targets using this mirror as a retroreflector was also demonstrated.

Resonant inelastic scattering of quasifree electrons on ions

International Nuclear Information System (INIS)

Grabbe, S.

1994-01-01

Several studies of resonant-transfer excitation (RTE) have been reported in ion-atom collisions where the doubly excited autoionizing states are produced. Such a complex collision can be approximated as the scattering of quasifree electrons of the target from the projectile ion. Most of the investigations have been restricted to the deexcitation of the autoionizing states to the ground state by Auger electron emission. It has been shown that there is a strong interference between the elastic scattering amplitude and the resonance amplitude. The authors present here the cases where the corresponding interference is between the inelastic scattering and the resonance process. Recent work on 3 ell 3 ell ' resonances that decay predominantly to n=2 states will be presented for C 5+ -molecular hydrogen collisions

Reduction of stimulated Brillouin backscattering with plasma beam smoothing

Energy Technology Data Exchange (ETDEWEB)

Yahia, V.; Loisel, G.; Baccou, C.; Labaune, C. [Laboratoire pour l' Utilisation des Lasers Intenses, Ecole Polytechnique, Palaiseau (France); Masson-Laborde, P.-E.; Depierreux, S.; Goyon, C.; Teychenné, D. [CEA, DAM, DIF, F-91297 Arpajon (France); Borisenko, N. G.; Orekhov, A. [P.N. Lebedev Physical Institute, Russian Academy of Science, Moscow (Russian Federation); Rienecker, T.; Rosmej, O. [GSI Helmhotzzentrum fur Schwerionenforschung, 64291 Darmstadt (Germany)

2015-04-15

Plasma induced incoherence (PII) can strongly modify the growth rates of stimulated scattering instabilities. A special double-target design was used to quantify the effect of PII on stimulated Brillouin scattering (SBS). Successive shots using all or part of these targets led to the characterization of temporal and spatial incoherence of a laser pulse after propagation through a foam plasma and to the quantification of the reduction of SBS from the second target. Numerical simulations were used to identify the main physical mechanisms in play.

Interference scattering effects on intermediate resonance absorption at operating temperatures

International Nuclear Information System (INIS)

Goldstein, R.

1975-01-01

Resonance integrals may be accurately calculated using the intermediate resonance (IR) approximation. Results are summarized for the case of an absorber with given potential scattering cross sections and interference scattering parameter admixed with a non absorbing moderator of given cross section and located in a narrow resonance moderating medium. From the form of the IR solutions, it is possible to make some general observations about effects of interference scattering on resonance absorption. 2 figures

Interfacial Dzyaloshinskii-Moriya interaction sign in Ir/Co2FeAl systems investigated by Brillouin light scattering

Science.gov (United States)

Belmeguenai, M.; Gabor, M. S.; Roussigné, Y.; Petrisor, T.; Mos, R. B.; Stashkevich, A.; Chérif, S. M.; Tiusan, C.

2018-02-01

C o2FeAl (CFA) ultrathin films, of various thicknesses (0.9 nm ≤tCFA≤1.8 nm ), have been grown by sputtering on Si substrates, using Ir as a buffer layer. The magnetic properties of these structures have been studied by vibrating sample magnetometry (VSM), miscrostrip ferromagnetic resonance (MS-FMR), and Brillouin light scattering (BLS) in the Damon-Eshbach geometry. VSM characterizations show that films are mostly in-plane magnetized and the saturating field perpendicular to the film plane increases with decreasing CFA thickness suggesting the existence of a perpendicular interface anisotropy. The presence of a magnetic dead layer of 0.44 nm has been detected by VSM. The MS-FMR with the magnetic field applied perpendicularly to the film plane has been used to determine the gyromagnetic factor. The BLS measurements reveal a pronounced nonreciprocal spin wave propagation, due to the interfacial Dzyaloshinskii-Moriya interaction (DMI) induced by the Ir interface with CFA, which increases with decreasing CFA thickness. The DMI sign has been found to be the same (negative) as that of Pt/Co, in contrast to the ab initio calculation on Ir/Co, where it is found to be positive. The thickness dependence of the effective DMI constant shows the existence of two regimes similarly to that of the perpendicular anisotropy constant. The surface DMI constant Ds was estimated to be -0.37 pJ /m for the thickest samples, where a linear thickness dependence of the effective DMI constant has been observed.

Resonant inelastic scattering by use of geometrical optics.

Science.gov (United States)

Schulte, Jörg; Schweiger, Gustav

2003-02-01

We investigate the inelastic scattering on spherical particles that contain one concentric inclusion in the case of input and output resonances, using a geometrical optics method. The excitation of resonances is included in geometrical optics by use of the concept of tunneled rays. To get a quantitative description of optical tunneling on spherical surfaces, we derive appropriate Fresnel-type reflection and transmission coefficients for the tunneled rays. We calculate the inelastic scattering cross section in the case of input and output resonances and investigate the influence of the distribution of the active material in the particle as well as the influence of the inclusion on inelastic scattering.

Alpha resonant scattering for astrophysical reaction studies

International Nuclear Information System (INIS)

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.

2014-01-01

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 7 Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the 7 Be(α,γ) reaction, and proposed a new cluster band in 11 C

Coherent beam combination using self-phase locked stimulated Brillouin scattering phase conjugate mirrors with a rotating wedge for high power laser generation.

Science.gov (United States)

Park, Sangwoo; Cha, Seongwoo; Oh, Jungsuk; Lee, Hwihyeong; Ahn, Heekyung; Churn, Kil Sung; Kong, Hong Jin

2016-04-18

The self-phase locking of a stimulated Brillouin scattering-phase conjugate mirror (SBS-PCM) allows a simple and scalable coherent beam combination of existing lasers. We propose a simple optical system composed of a rotating wedge and a concave mirror to overcome the power limit of the SBS-PCM. Its phase locking ability and the usefulness on the beam-combination laser are demonstrated experimentally. A four-beam combination is demonstrated using this SBS-PCM scheme. The relative phases between the beams were measured to be less than λ/24.7.

Two-stage optical parametric chirped-pulse amplifier using sub-nanosecond pump pulse generated by stimulated Brillouin scattering compression

Science.gov (United States)

Ogino, Jumpei; Miyamoto, Sho; Matsuyama, Takahiro; Sueda, Keiichi; Yoshida, Hidetsugu; Tsubakimoto, Koji; Miyanaga, Noriaki

2014-12-01

We demonstrate optical parametric chirped-pulse amplification (OPCPA) based on two-beam pumping, using sub-nanosecond pulses generated by stimulated Brillouin scattering compression. Seed pulse energy, duration, and center wavelength were 5 nJ, 220 ps, and ˜1065 nm, respectively. The 532 nm pulse from a Q-switched Nd:YAG laser was compressed to ˜400 ps in heavy fluorocarbon FC-40 liquid. Stacking of two time-delayed pump pulses reduced the amplifier gain fluctuation. Using a walk-off-compensated two-stage OPCPA at a pump energy of 34 mJ, a total gain of 1.6 × 105 was obtained, yielding an output energy of 0.8 mJ. The amplified chirped pulse was compressed to 97 fs.

OPTICAL DATA PROCESSING: Realization of associative memory with the aid of a nonlinear selective stimulated-Brillouin-scattering mirror

Science.gov (United States)

Matveyev, A. Z.; Pasmanik, G. A.

1993-05-01

An associative memory using only optical elements has been realized experimentally. The key element of the arrangement is a stimulated-Brillouin-scattering (SBS) selector consisting of a short SBS medium at the focus of a lens. The qualitative advantage of the selector over an SBS mirror is demonstrated experimentally. The response time of the arrangement is ~ 10-8 s and is determined by the duration of the SBS. Estimates show that the SBS selector is capable in practice of distinguishing a signal against background noise when the initial distortion level of the object beam is 10-3. Reliable operation of the SBS selector has been demonstrated for radiative and energy loads reaching 2 GW/cm2 and 2 J, respectively.

Brillouin Light Scattering from Magnetic Excitations in Superparamagnetic and Ferromagnetic Co-Al-O Granular Films

Science.gov (United States)

Yoshihara, Akira; Maeda, Toshiteru; Kawamura, Satoshi; Nakamura, Shintaro; Nojima, Tsutomu; Takeda, Yoshihiko; Ohnuma, Shigehiro

2018-04-01

A systematic study of Brillouin light scattering (BLS) from superparamagnetic (SPM) and ferromagnetic (FM) Co-Al-O granular films was performed under magnetic fields of up to 4.6 kOe in the standard backscattering geometry at room temperature. The SPM and FM boundary, defined as the Co composition at which the exchange field vanishes, was found to be located at xC(Co) = 59.3 ± 1.3 at. %. From FM films we observed a pair of bulk spin-wave peaks on both the positive- and negative-frequency sides and a surface localized Damon-Eshbach peak only on the positive-frequency side under the present scattering conditions. From SPM films, a pair of broader but propagative excitation peaks with asymmetric intensity were observed on both frequency sides in a spectrum. We performed a numerical analysis of the BLS spectrum by employing the theory developed by Camley and Mills (CM) while retaining dipole and exchange couplings for FM films and only dipole coupling for SPM films. The CM theory successfully reproduced the observed spectrum for both SPM and FM films. The SPM spectrum exhibits a singlet-doublet peak structure similarly to an FM SW spectrum. The SPM peak stems from the dipole-coupled larger-amplitude precession motion of the granule magnetic moment around the external-field-induced magnetization.

Alpha resonant scattering for astrophysical reaction studies

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubano, S. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y. K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D. N. [30 MeV Cyclotron Center, Tran Hung Dao Hospital, Hoan Kiem District, Hanoi (Viet Nam); Khiem, L. H.; Duy, N. G. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, Hanoi (Viet Nam)

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.

Phase-detected Brillouin optical correlation-domain reflectometry

Science.gov (United States)

Mizuno, Yosuke; Hayashi, Neisei; Fukuda, Hideyuki; Nakamura, Kentaro

2018-05-01

Optical fiber sensing techniques based on Brillouin scattering have been extensively studied for structural health monitoring owing to their capability of distributed strain and temperature measurement. Although a higher signal-to-noise ratio (leading to high spatial resolution and high-speed measurement) is generally obtained for two-end-access systems, they reduce the degree of freedom in embedding the sensors into structures, and render the measurement no longer feasible when extremely high loss or breakage occurs at a point of the sensing fiber. To overcome these drawbacks, a one-end-access sensing technique called Brillouin optical correlation-domain reflectometry (BOCDR) has been developed. BOCDR has a high spatial resolution and cost efficiency, but its conventional configuration suffered from relatively low-speed operation. In this paper, we review the recently developed high-speed configurations of BOCDR, including phase-detected BOCDR, with which we demonstrate real-time distributed measurement by tracking a propagating mechanical wave. We also demonstrate breakage detection with a wide strain dynamic range.

Resonant scattering of surface plasmon polaritons by dressed quantum dots

Energy Technology Data Exchange (ETDEWEB)

Huang, Danhong; Cardimona, Dave [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117 (United States); Easter, Michelle [Department of Mechanical Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, New Jersey 07030 (United States); Gumbs, Godfrey [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States); Maradudin, A. A. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Lin, Shawn-Yu [Department of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180 (United States); Zhang, Xiang [Department of Mechanical Engineering, 3112 Etcheverry Hall, University of California at Berkeley, Berkeley, California 94720 (United States)

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.

Photon scattering by the giant dipole resonance

International Nuclear Information System (INIS)

Bowles, T.J.; Holt, R.J.; Jackson, H.E.; McKeown, R.D.; Specht, J.R.

1979-01-01

Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were 60 Ni, 52 Cr, 56 Fe, 92 Mo, and 96 Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but 60 Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables

Resonance interaction of heavy ions in radar scattering

International Nuclear Information System (INIS)

Strutinskij, V.M.

1983-01-01

Resonances on back angles in the process of scatterina of heavy ions are investigated. Comprehensive investigation into possible sources of irregular structure of angular distribution during elastic scattering (ES) on wide angles are compated with an experiment. The first source is a two-component interference and the second one is a resonance structure connected with the process of formation of definite nucleon states in strongly deformed intermediate nucleus. Comparison of radar cross section calculations (back scattering cross section) with angular ES distributions of hydrogen on silicon testifies a possibility to interpret an anomalous scattering on wide angles in some reactions with heavy ions as a result of modulation of partial amplitudes by resonances of the input state typein the initial state of interaction of two nuclei

A single-longitudinal-mode Brillouin fiber laser passively stabilized at the pump resonance frequency with a dynamic population inversion grating

International Nuclear Information System (INIS)

Spirin, V V; López-Mercado, C A; Kinet, D; Mégret, P; Fotiadi, A A; Zolotovskiy, I O

2013-01-01

We demonstrate a single-longitudinal-mode Brillouin ring fiber laser passively stabilized at the resonance frequency with a 1.7 m section that is an unpumped polarization-maintaining erbium-doped fiber. The two coupled all-fiber Fabry–Perot interferometers that comprise the cavity, in combination with the dynamical population inversion gratings self-induced in the active fiber, provide adaptive pump-mode selection and Stokes wave generation at the same time. The laser is shown to emit a single-frequency Stokes wave with a linewidth narrower than 100 Hz. (letter)

Investigation on the elastic properties of Gd-Sc-Al garnet by the Mandelstam-Brillouin light scattering method

International Nuclear Information System (INIS)

Zharikov, E.V.; Zagumennyj, A.I.; Kitaeva, V.F.; Lutts, G.B.; Terskov, D.B.

1991-01-01

The Gd-Sc-Al garnet (GSAG) crystals grown from the melt with composition Gd 2.88 Sc 1.89 Al 3.23 O 12 , were investigated. The GSAG doped with chromium was also studied. The Mandelstam-Brillouin (MB) light scattering in the GSAG crystals was observed. The garnet elastic components were determined using the data on the MB component shifts, the products of the elastic constants by molar volume were calculated as well. The GSAG is elastically anisotropic. The doping addition introduction do not cause noticeable change in the elastic properties. The obtained values of elastic constants and their combinations for GSAG were compared with the data for aluminium and gallium garnets. The comparison has shown that the values of elastic constants for GSAG is closer to those for Gd-Sc-Ga garnet than to the corresponding values for the Y-Al one

Resonances in the proton-6Li scattering

International Nuclear Information System (INIS)

Haller, M.

1986-01-01

The differential cross section and the analyzing power of the p+ 6 Li scattering were measured in the laboratory energy range from 1.6 respectively 2.8 MeV to 10 MeV at 45 respectively 40 energies in full angular distributions. The data were subjected both to an analysis in the optical model which yielded already hints to resonance effects and to a comphrehensive scattering-phase analysis for L=0, 1, and 2 under inclusion of channel spin and orbital angular momentum mixings. The consistent description of all data required the assumption of broad resonance structures. An approximate parametrization by a Breit-Wigner formula allowed the estimation of the resonance parameters. (orig./HSI) [de

Auger vs resonance neutralization in low energy He+ ion scattering

International Nuclear Information System (INIS)

Woodruff, D.P.

1983-01-01

He + ions incident on a metal surface can neutralize either by an Auger or resonant charge exchange. While the Auger process has always been thought to be dominant, recent theoretical interest in the simpler one-electron resonance process has led to suggestions that this alone can account for the neutralization seen in low energy He + ion scattering. In this paper this assertion is analysed by looking at the wider information available on charge exchange processes for He + ion scattering through comparison with Li + ion scattering, the importance of multiple scattering in both these scattering experiments and the results of ion neutralization spectroscopy. These lead to the conclusion that while resonance neutralization to produce metastable He* may well occur at a substantial rate in He + ion scattering, the dominant process leading to loss of ions from the final scattered signal is Auger neutralization as originally proposed. (author)

Nonlinear Brillouin amplification of finite-duration seeds in the strong coupling regime

International Nuclear Information System (INIS)

Lehmann, G.; Spatschek, K. H.

2013-01-01

Parametric plasma processes received renewed interest in the context of generating ultra-intense and ultra-short laser pulses up to the exawatt-zetawatt regime. Both Raman as well as Brillouin amplifications of seed pulses were proposed. Here, we investigate Brillouin processes in the one-dimensional (1D) backscattering geometry with the help of numerical simulations. For optimal seed amplification, Brillouin scattering is considered in the so called strong coupling (sc) regime. Special emphasis lies on the dependence of the amplification process on the finite duration of the initial seed pulses. First, the standard plane-wave instability predictions are generalized to pulse models, and the changes of initial seed pulse forms due to parametric instabilities are investigated. Three-wave-interaction results are compared to predictions by a new (kinetic) Vlasov code. The calculations are then extended to the nonlinear region with pump depletion. Generation of different seed layers is interpreted by self-similar solutions of the three-wave interaction model. Similar to Raman amplification, shadowing of the rear layers by the leading layers of the seed occurs. The shadowing is more pronounced for initially broad seed pulses. The effect is quantified for Brillouin amplification. Kinetic Vlasov simulations agree with the three-wave interaction predictions and thereby affirm the universal validity of self-similar layer formation during Brillouin seed amplification in the strong coupling regime

Does Brillouin light scattering probe the primary glass transition process at temperatures well above glass transition?

Science.gov (United States)

Voudouris, P; Gomopoulos, N; Le Grand, A; Hadjichristidis, N; Floudas, G; Ediger, M D; Fytas, G

2010-02-21

The primary alpha-relaxation time (tau(alpha)) for molecular and polymeric glass formers probed by dielectric spectroscopy and two light scattering techniques (depolarized light scattering and photon correlation spectroscopy) relates to the decay of the torsional autocorrelation function computed by molecular dynamics simulation. It is well known that Brillouin light scattering spectroscopy (BLS) operating in gigahertz frequencies probes a fast (10-100 ps) relaxation of the longitudinal modulus M*. The characteristic relaxation time, irrespective of the fitting procedure, is faster than the alpha-relaxation which obeys the non-Arrhenius Vogel-Fulcher-Tammann equation. Albeit, this has been noticed, it remains a puzzling finding in glass forming systems. The available knowledge is based only on temperature dependent BLS experiments performed, however, at a single wave vector (frequency). Using a new BLS spectrometer, we studied the phonon dispersion at gigahertz frequencies in molecular [o-terphenyl (OTP)] and polymeric [polyisoprene (PI) and polypropylene (PP)] glass formers. We found that the hypersonic dispersion does relate to the glass transition dynamics but the disparity between the BLS-relaxation times and tau(alpha) is system dependent. In PI and PP, the former is more than one order of magnitude faster than tau(alpha), whereas the two relaxation times become comparable in the case of OTP. The difference between the two relaxation times appears to relate to the "breadth" of the relaxation time distribution function. In OTP the alpha-relaxation process assumes a virtually single exponential decay at high temperatures well above the glass transition temperature, in clear contrast with the case of the amorphous bulk polymers.

Stimulated Brillouin scattering reflectivity in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma

International Nuclear Information System (INIS)

Tikhonchuk, V.T.; Mounaix, P.; Pesme, D.

1997-01-01

The stimulated Brillouin scattering (SBS) instability is investigated theoretically in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma in the regime of strong ion acoustic damping. The domain of parameters being considered corresponds to most of the present day experiments carried out with nanosecond laser pulses interacting with preformed plasmas: the characteristic length for convective amplification is assumed to be much shorter than the longitudinal correlation length of the laser field. The SBS reflectivity of one individual hot spot is analytically computed taking into account thermal noise emission and pump depletion within the hot spot. The SBS reflectivity of the whole beam is then obtained by summing up the individual hot spot reflectivities in accordance with their statistical distribution. copyright 1997 American Institute of Physics

Resonance scattering of Rayleigh waves by a mass defect

International Nuclear Information System (INIS)

Croitoru, M.; Grecu, D.

1978-06-01

The resonance scattering of an incident Rayleigh wave by a mass defect extending over a small cylindrical region situated in the surface of a semi-infinite isotropic, elastic medium is investigated by means of the Green's function method. The form of the differential cross-section for the scattering into different channels exhibits a strong resonance phenomenon at two frequencies. The expression of the resonance frequencies as well as of the corresponding widths depends on the relative change in mass density. The main assumption that the wavelengths of incoming and scattered wave are large compared to the defect dimension implies a large relative mass-density change. (author)

Resonance magnetic x-ray scattering study of erbium

DEFF Research Database (Denmark)

Sanyal, M.K.; Gibbs, D.; Bohr, J.

1994-01-01

The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...... of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior of the magnetic...

Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

Science.gov (United States)

Chin, Sanghoon; Thévenaz, Luc; Sancho, Juan; Sales, Salvador; Capmany, José; Berger, Perrine; Bourderionnet, Jérôme; Dolfi, Daniel

2010-10-11

We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

Resonant Impulsive Stimulated Raman Scattering

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, A; Chesnoy, J

1988-03-15

Using a femtosecond dye laser, we observe in real-time vibrational oscillations excited by impulsive stimulated Raman scattering (ISRS) close to an electronic resonance. We perform single-beam Raman excitation and probe the driven coherence by a polarization-sensitive detection. We demonstrate for the first time impulsively Raman-induced dichroism, birefringence as well as frequency and time delay shifts. We analyse the characteristics of resonant ISRS on a vibrational mode of a dye molecule (malachite green) in solution.

Resonant Impulsive Stimulated Raman Scattering

International Nuclear Information System (INIS)

Mokhtari, A.; Chesnoy, J.

1988-01-01

Using a femtosecond dye laser, we observe in real-time vibrational oscillations excited by impulsive stimulated Raman scattering (ISRS) close to an electronic resonance. We perform single-beam Raman excitation and probe the driven coherence by a polarization-sensitive detection. We demonstrate for the first time impulsively Raman-induced dichroism, birefringence as well as frequency and time delay shifts. We analyse the characteristics of resonant ISRS on a vibrational mode of a dye molecule (malachite green) in solution

Shape dependent resonance light scattering properties of gold nanorods

International Nuclear Information System (INIS)

Zhu Jian; Huang Liqing; Zhao Junwu; Wang Yongchang; Zhao Yanrui; Hao Limei; Lu Yimin

2005-01-01

Suspended gold nanorods with mean aspect ratio 2.5 have been synthesized via electrochemical method. Resonance scattering properties have been studied. Two scattering peaks fixed at 400 and 640 nm are due to the scattering of the gold nanorods via coupling to the transverse and longitudinal surface plasmon resonance. The quasi-static calculation results indicate that with the increasing aspect ratio of the nanorods, the longer wavelength scattering peak red shifts linearly and the shorter wavelength peak blue shifts non-linearly. When aspect ratio a/b = 1.0, ellipse degenerate to sphere and the two peaks unite into one peak at 450 nm

Resonances in the potential scattering and decay of metastable states

International Nuclear Information System (INIS)

Batsch, J.

1975-04-01

The analytic properties of the S-matrix in the complex energy plane are reviewed for potential scattering with particular attention to resonance scattering and decay of metastable states. For a one dimensional model potential with a potential barrier and a repulsive core exact formulas are derived for the energy and width of a resonance in terms of the scattering amplitudes of the barrier and the repulsive core alone. For narrow resonances simple and intuitive results are obtained, which are applied to semiclassical cases where the WKB approximation is valid. (orig.) [de

Brillouin-Mandelstam spectroscopy of standing spin waves in a ferrite waveguide

Science.gov (United States)

Balinskiy, Michael; Kargar, Fariborz; Chiang, Howard; Balandin, Alexander A.; Khitun, Alexander G.

2018-05-01

This article reports results of experimental investigation of the spin wave interference over large distances in the Y3Fe2(FeO4)3 waveguide using Brillouin-Mandelstam spectroscopy. Two coherent spin waves are excited by the micro-antennas fabricated at the edges of the waveguide. The amplitudes of the input spin waves are adjusted to provide approximately the same intensity in the central region of the waveguide. The relative phase between the excited spin waves is controlled by the phase shifter. The change of the local intensity distribution in the standing spin wave is monitored using Brillouin-Mandelstam light scattering spectroscopy. Experimental data demonstrate the oscillation of the scattered light intensity depending on the relative phase of the interfering spin waves. The oscillations of the intensity, tunable via the relative phase shift, are observed as far as 7.5 mm away from the spin-wave generating antennas at room temperature. The obtained results are important for developing techniques for remote control of spin currents, with potential applications in spin-based memory and logic devices.

Acoustic Phonons and Mechanical Properties of Ultra-Thin Porous Low-k Films: A Surface Brillouin Scattering Study

Science.gov (United States)

Zizka, J.; King, S.; Every, A.; Sooryakumar, R.

2018-04-01

To reduce the RC (resistance-capacitance) time delay of interconnects, a key development of the past 20 years has been the introduction of porous low-k dielectrics to replace the traditional use of SiO2. Moreover, in keeping pace with concomitant reduction in technology nodes, these low-k materials have reached thicknesses below 100 nm wherein the porosity becomes a significant fraction of the film volume. The large degree of porosity not only reduces mechanical strength of the dielectric layer but also renders a need for non-destructive approaches to measure the mechanical properties of such ultra-thin films within device configurations. In this study, surface Brillouin scattering (SBS) is utilized to determine the elastic constants, Poisson's ratio, and Young's modulus of these porous low-k SiOC:H films (˜ 25-250 nm thick) grown on Si substrates by probing surface acoustic phonons and their dispersions.

Chemical binding effects in resonance - potential interference scattering for harmonic crystals

International Nuclear Information System (INIS)

Kuwaifi, A.; Summerfield, G.C.

1991-01-01

The neutron scattering cross section which is the quantity directly measured in experiments is given by the absolute square of the scattering amplitude. For energies near a resonance, this yields three terms: potential, resonant and interference. In this paper we deal with the interference neutron scattering cross section which is written in terms of a three-point correlation function. This function is calculated for the ideal gas and harmonic crystal models. For short collision times, the interference result for harmonic crystals is the same as the ideal gas but it has an effective temperature. This is the same effective temperature as was previously found for absorption and pure resonant processes. Therefore, the interference scattering cross section can be treated in the same way as resonant scattering and absorption are treated using an ideal gas result with the usual effective temperature. (author)

Influence of chirp on laser-pulse amplification in Brillouin backscattering schemes

Science.gov (United States)

Lehmann, Goetz; Schluck, Friedrich; Spatschek, Karl-Heinz

2015-11-01

Plasma-based amplification of laser pulses is currently discussed as a key component for the next generation of high-intensity laser systems, possibly enabling the generation of ultra-short pulses in the exawatt-zetawatt regime. In these scenarios the energy of a long pump pulse (several ps to ns of duration) is transferred to a short seed pulse via a plasma oscillation. Weakly- and strongly-coupled (sc) Brillouin backscattering have been identified as potential candidates for robust amplification scenarios. With the help of three-wave interaction models, we investigate the influence of a chirp of the pump beam on the seed amplification. We show that chirp can mitigate deleterious spontaneous Raman backscattering of the pump off noise and that at the same time the amplification dynamics due to Brillouin scattering is still intact. For the experimentally very interesting case of sc-Brillouin we find a dependence of the efficiency on the sign of the chirp. Funding provided by project B10 of SFB TR18 of the Deutsche Forschungsgemeinschaft (DFG).

Stimulated Brillouin scattering phase-locking using a transient acoustic standing wave excited through an optical interference field

International Nuclear Information System (INIS)

Ondrej Slezak; Milan Kalal; Hon Jin Kong

2010-01-01

Complete text of publication follows. Analytical description of an experimentally verified scheme leading to a phase-locked stimulated Brillouin scattering (SBS), used in a laser beam combination systems, is presented. The essential condition for the phase-locking effect for SBS is the fixation of the starting position and time of the acoustic Brillouin wave. It is shown that the starting position fixation of this acoustic wave may have its origin in a transient acoustic standing wave initiated by an arising optical interference field produced by the back-seeding concave mirror. This interference field leads to a stationary density modulation of the medium. However, the way to the formation of this density modulation leads via the acoustic standing wave. An appropriate solution, in the form of the standing wave, was obtained from solving the acoustic wave-equation using the electrostriction as a driving force. As a consequence of the damping term included in this equation the acoustic standing wave becomes gradually attenuated and contrary to the undamped solution published earlier, thus constitutes a truly transient phenomenon. Using a mathematical formalism similar to that which is used for the SBS description in the case of a random phase, the coupled equations describing the phase-locked SBS were derived. Contrary to the case without the back-seeding mirror, where the wave chosen from the thermal noise background subsequently plays the role of a trigger of the stimulated process, in this case it is replaced by the transient standing wave produced as a consequence of the presence of an optical interference field arisen in the focal region of the back-seeding concave mirror.

An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

International Nuclear Information System (INIS)

Bradley, K.S.

1993-01-01

Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory's assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this series of experiments was the development of a new instrument, the Multiple Angle Time Resolving Spectrometer (MATRS). MATRS has the unique capability of both spectrally and temporally resolving absolute levels of scattered light at many angles simultaneously, and is the first of its kind used in laser-plasma experiments. A detailed comparison of the theoretical predictions and the experimental observations is made

Nuclear resonance scattering of synchrotron radiation as a unique electronic, structural and thermodynamic probe

International Nuclear Information System (INIS)

Alp, E. Ercan; Sturhahn, Wolfgang; Toellner, Thomas S.; Zhao, Jiyong; Leu, Bogdan M.

2012-01-01

Discovery of Moessbauer effect in a nuclear transition was a remarkable development. It revealed how long-lived nuclear states with relatively low energies in the kiloelectron volt (keV) region can be excited without recoil. This new effect had a unique feature involving a coupling between nuclear physics and solid-state physics, both in terms of physics and sociology. Physics coupling originates from the fact that recoilless emission and absorption or resonance is only possible if the requirement that nuclei have to be bound in a lattice with quantized vibrational states is fulfilled, and that the finite electron density on the nucleus couples to nuclear degrees of freedom leading to hyperfine interactions. thus, Moessbauer spectroscopy allows peering into solid-state effects using unique nuclear transitions. Sociological aspects of this coupling had been equally startling and fruitful. The interaction between diverse scientific communities, who learned to use Moessbauer spectroscopy proved to be very valuable. For example, biologists, geologists, chemists, physics, materials scientists, and archeologists, all sharing a common spectroscopic technique, also learned to appreciate the beauty and intricacies of each other's fields. As a laboratory-based technique, Moessbauer spectroscopy matured by the end of the 1970s. Further exciting developments took place when accelerator-based techniques were employed, like synchrotron radiation or 'in-beam'Moessbauer experiments with implanted radioactive ions. More recently, two Moessbauer spectrometers on the surface of the Mars kept the technique vibrant and viable up until present time. In this chapter, the authors look into some of the unique aspects of nuclear resonance excited with synchrotron radiation as a probe of condensed matter, including magnetism, valence, vibrations, and lattice dynamics, and review the development of nuclear resonance inelastic x-ray scattering (NRIXS) and synchrotron Moessbauer spectroscopy

Resonant magnetic scattering of polarized soft x rays

Energy Technology Data Exchange (ETDEWEB)

Sacchi, M. [Centre Universitaire Paris-Sud, Orsay (France); Hague, C.F. [Universite Pierre et Marie Curie, Paris (France); Gullikson, E.M.; Underwood, J. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

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.

Surface Brillouin scattering measurement of the elastic constants of single crystal InAs0.91Sb0.09

International Nuclear Information System (INIS)

Kotane, L M; Comins, J D; Every, A G; Botha, J R

2011-01-01

Surface Brillouin scattering of light has been used to measure the angular dependence of the Rayleigh surface acoustic wave (SAW), pseudo surface acoustic wave (PSAW) and longitudinal lateral wave (LLW) speeds in a (100)-oriented single crystal of the ternary semiconductor alloy InAs 0.91 Sb 0.09 . The wave speed measurements have been used to determine the room temperature values of the elastic constants C 11 , C 12 and C 44 of the alloy. A simple and robust fitting procedure has been implemented for recovering the elastic constants, in which the merit function is constructed from explicit secular functions that determine the surface and lateral wave speeds in the [001] and [011] crystallographic directions. In the fitting, relatively larger weighting factors have been assigned to the SAW and PSAW data because of the greater precision with which the surface modes can be measured as compared with the lateral wave.

Some Notes on Neutron Up-Scattering and the Doppler-Broadening of High-Z Scattering Resonances

Energy Technology Data Exchange (ETDEWEB)

Parsons, Donald Kent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-28

When neutrons are scattered by target nuclei at elevated temperatures, it is entirely possible that the neutron will actually gain energy (i.e., up-scatter) from the interaction. This phenomenon is in addition to the more usual case of the neutron losing energy (i.e., down-scatter). Furthermore, the motion of the target nuclei can also cause extended neutron down-scattering, i.e., the neutrons can and do scatter to energies lower than predicted by the simple asymptotic models. In recent years, more attention has been given to temperature-dependent scattering cross sections for materials in neutron multiplying systems. This has led to the inclusion of neutron up-scatter in deterministic codes like Partisn and to free gas scattering models for material temperature effects in Monte Carlo codes like MCNP and cross section processing codes like NJOY. The free gas scattering models have the effect of Doppler Broadening the scattering cross section output spectra in energy and angle. The current state of Doppler-Broadening numerical techniques used at Los Alamos for scattering resonances will be reviewed, and suggestions will be made for further developments. The focus will be on the free gas scattering models currently in use and the development of new models to include high-Z resonance scattering effects. These models change the neutron up-scattering behavior.

Stimulated resonant scattering at stressed fused silica surface

International Nuclear Information System (INIS)

Bouchut, Philippe; Reymermier, Maryse

2015-01-01

The radiative emission in CO 2 laser heated stressed fused silica is radically modified when gold microspheres are on the surface. At high heating rates, the emission dynamics changes from thermoluminescence to stimulated resonant scattering with an emission rate that is increased tenfold and the near infrared (NIR) spectrum is red-shifted. We show that the dynamic tensile stress that rises in heated silica is coupled with a fluctuating electromagnetic field that enables electromagnetic friction between moving OH emitters from silica bulk and NIR resonant scatterers at the silica surface. (paper)

Resonant and nonresonant magnetic scattering (invited)

International Nuclear Information System (INIS)

McWhan, D.B.; Hastings, J.B.; Kao, C.; Siddons, D.P.

1992-01-01

The tunability and the polarization of synchrotron radiation open up new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and they fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin-polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation

Brillouin light scattering investigation of interfacial Dzyaloshinskii–Moriya interaction in ultrathin Co/Pt nanostripe arrays

Science.gov (United States)

Bouloussa, H.; Yu, J.; Roussigné, Y.; Belmeguenai, M.; Stashkevitch, A.; Yang, H.; Chérif, S. M.

2018-06-01

Interface Dzyaloshinskii–Moriya interaction (iDMI) is known to induce spinwaves non-reciprocity in ultrathin films. Indeed, Brillouin light scattering has been used to investigate how the lateral size reduction can affect the iDMI constant in Pt (6 nm)/Co (3 nm) based-nanostripe arrays. For this, 100 and 300 nm-width nanostripes have been fabricated using e-beam lithography and ion etching, and their behaviour has then been compared to the reference continuous film. The experimental data showed that the measured iDMI induced non-reciprocity is slightly different for the 100 nm-width nanostripes with respect to the other samples. This suggests that the width of the nanostripes can influence the strength of the apparent iDMI if this dimension is comparable to the spin waves attenuation length propagating within the nanostripes. Indeed, in contrast to the other samples, the linear frequency difference (non-reciprocity) behaviour versus wavenumber for the 100 nm-width nanostripes has been analysed and discussed through two approaches: either a different iDMI constant or an iDMI constant similar to one of the continuous films with a non-zero intercept for a zero wavenumber.

pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

Science.gov (United States)

Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

2015-11-01

We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

Controllable scattering of photons in a one-dimensional resonator waveguide

Science.gov (United States)

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

Photon induced resonant Raman scattering in CdS

International Nuclear Information System (INIS)

Muzart, J.; Lluesma, E.G.; Arguello, C.A.; Leite, R.C.C.

1975-01-01

A novel aspect of resonant Raman scattering is observed in CdS by means of the ratio of Stokes to anti-Stokes intensities. With increasing temperature, as the forbidden band energy approaches a value that is twice the incident photon energy, (from a Nd-Yag-laser) a large enhancement of the above ratio is observed for both the LO and the 2LO phonon Raman intensities. The results indicate a resonance with the scattered photon. Resonance is only observed for high incident photon intensities. A possible explanation for the above observations is that flooding of the crystal with photons of energy hν induces states of energy hν displaced from the electronic bands by mixing of electronic and photon states

Light Scattering by a Dielectric Sphere: Perspectives on the Mie Resonances

Directory of Open Access Journals (Sweden)

Dimitrios Tzarouchis

2018-01-01

Full Text Available Light scattering by a small spherical particle, a central topic for electromagnetic scattering theory, is here considered. In this short review, some of the basic features of its resonant scattering behavior are covered. First, a general physical picture is described by a full electrodynamic perspective, the Lorenz–Mie theory. The resonant spectrum of a dielectric sphere reveals the existence of two distinctive types of polarization enhancement: the plasmonic and the dielectric resonances. The corresponding electrostatic (Rayleigh picture is analyzed and the polarizability of a homogeneous spherical inclusion is extracted. This description facilitates the identification of the first type of resonance, i.e., the localized surface plasmon (plasmonic resonance, as a function of the permittivity. Moreover, the electrostatic picture is linked with the plasmon hybridization model through the case of a step-inhomogeneous structure, i.e., a core–shell sphere. The connections between the electrostatic and electrodynamic models are reviewed in the small size limit and details on size-induced aspects, such as the dynamic depolarization and the radiation reaction on a small sphere are exposed through the newly introduced Mie–Padé approximative perspective. The applicability of this approximation is further expanded including the second type of resonances, i.e., the dielectric resonances. For this type of resonances, the Mie–Padé approximation reveals the main character of the two different cases of resonances of either magnetic or electric origin. A unified picture is therefore described encompassing both plasmonic and dielectric resonances, and the resonant conditions of all three different types are extracted as functions of the permittivity and the size of the sphere. Lastly, the directional scattering behavior of the first two dielectric resonances is exposed in a simple manner, namely the Kerker conditions for maximum forward and

Resonant proton scattering of $^{22}$Mg and $^{21}$Na

CERN Multimedia

Di julio, D D; Jansson, K; Rudolph, D; Fynbo, H O U; Nilsson, T; Perea martinez, A

In our letter-of-intent, INTC-I-051, we discussed the physics case for scattering and transfer reactions involving light nuclei in the break-out region of the rp-process. The Committee found the physics case compelling and supported the letter-of-intent under the premise that beams of proper quality were developed and that an adequate detector set-up was presented. As these two requirements have been met recently we now propose to study resonant proton scattering of $^{22}$Mg to identify the states at 1.733 MeV and 2.575 MeV in $^{23}$Al that have been reported from the $^{24}$Mg($^{7}$Li,$^{8}$He)$\\,^{23}\\!$Al reaction but that remained unobserved in the only resonant proton scattering experiment performed with $^{22}$Mg so far. In particular we should be able to investigate the character of the proton emission of the 2.575 MeV state which may also have a significant inelastic branch. We also propose to perform resonant proton scattering on $^{21}$Na above $\\alpha$-particle threshold with $^{18}$Ne to study ...

Interior and exterior resonances in acoustic scattering. pt. 1 - spherical targets

International Nuclear Information System (INIS)

Gaunaurd, G.C.; Tanglis, E.; Uberall, H.; Brill, D.

1983-01-01

In acoustic scattering from elastic objects, resonance features appear in the returned echo at frequencies at which the object's eigenfrequencies are located, which are explained by the excitation of 'interior' creeping waves. Corresponding resonance terms may be split off from the total scattering amplitude, leaving behind an apparently nonresonant background amplitude. This is demonstrated here for scatterers of spherical geometry and in a companion paper also for scatterers of arbitrary geometry, by using the T-matrix approach. For the case of near-impenetrable spheres, it is subsequently shown that the background amplitude can be split further into specularly reflected contributions, plus highly attenuated resonance terms which are explained by the excitation of 'exterior' (Franz-type) creeping waves. The singularity structure of the scattering function is shown mathematically, by using the R-matrix approach of the nuclear-scattering theory, as that of a meromorphic function 'without' any additional 'entire function' (as had been postulated by the singularity expansion method)

Scattering processes and resonances from lattice QCD

Science.gov (United States)

Briceño, Raúl A.; Dudek, Jozef J.; Young, Ross D.

2018-04-01

The vast majority of hadrons observed in nature are not stable under the strong interaction; rather they are resonances whose existence is deduced from enhancements in the energy dependence of scattering amplitudes. The study of hadron resonances offers a window into the workings of quantum chromodynamics (QCD) in the low-energy nonperturbative region, and in addition many probes of the limits of the electroweak sector of the standard model consider processes which feature hadron resonances. From a theoretical standpoint, this is a challenging field: the same dynamics that binds quarks and gluons into hadron resonances also controls their decay into lighter hadrons, so a complete approach to QCD is required. Presently, lattice QCD is the only available tool that provides the required nonperturbative evaluation of hadron observables. This article reviews progress in the study of few-hadron reactions in which resonances and bound states appear using lattice QCD techniques. The leading approach is described that takes advantage of the periodic finite spatial volume used in lattice QCD calculations to extract scattering amplitudes from the discrete spectrum of QCD eigenstates in a box. An explanation is given of how from explicit lattice QCD calculations one can rigorously garner information about a variety of resonance properties, including their masses, widths, decay couplings, and form factors. The challenges which currently limit the field are discussed along with the steps being taken to resolve them.

Magnetism in heterogeneous thin film systems: Resonant X-ray scattering studies

International Nuclear Information System (INIS)

Kortright, J.B.; Jiang, J.S.; Bader, S.D.; Hellwig, O.; Marguiles, D.T.; Fullerton, E.E.

2002-01-01

Magnetic and chemical heterogeneity are common in a broad range of magnetic thin film systems. Emerging resonant soft x-ray scattering techniques are well suited to resolve such heterogeneity at relevant length scales. Resonant x-ray magneto-optical Kerr effect measurements laterally average over heterogeneity but can provide depth resolution in different ways, as illustrated in measurements resolving reversible and irreversible changes in different layers of exchange-spring heterostructures. Resonant small-angle scattering measures in-plane heterogeneity and can resolve magnetic and chemical scattering sources in different ways, as illustrated in measurements of granular alloy recording media

Ideal Gas Resonance Scattering Kernel Routine for the NJOY Code

International Nuclear Information System (INIS)

Rothenstein, W.

1999-01-01

In a recent publication an expression for the temperature-dependent double-differential ideal gas scattering kernel is derived for the case of scattering cross sections that are energy dependent. Some tabulations and graphical representations of the characteristics of these kernels are presented in Ref. 2. They demonstrate the increased probability that neutron scattering by a heavy nuclide near one of its pronounced resonances will bring the neutron energy nearer to the resonance peak. This enhances upscattering, when a neutron with energy just below that of the resonance peak collides with such a nuclide. A routine for using the new kernel has now been introduced into the NJOY code. Here, its principal features are described, followed by comparisons between scattering data obtained by the new kernel, and the standard ideal gas kernel, when such comparisons are meaningful (i.e., for constant values of the scattering cross section a 0 K). The new ideal gas kernel for variable σ s 0 (E) at 0 K leads to the correct Doppler-broadened σ s T (E) at temperature T

Stimulated Brillouin backscattering losses in weakly inhomogeneous laser-produced plasmas

International Nuclear Information System (INIS)

Eidmann, K.; Brederlow, G.; Brodmann, R.; Petsch, R.; Sigel, R.; Tsarkiris, G.; Volk, R.; Witkowski, S.

1979-02-01

Studies of the reflection from a plane solid target plasma produced with a 1TW iodine laser (lambda = 1.3μm) at pulse durations of 300 ps are presented. The specularly reflected and the backscattered light was observed separately at different angles of incidence, intensities and spot sizes (up to 400 μm). Stimulated Brillouin scattering was identified as the main mechanism for backscattering with saturation at 20 - 30% reflection. (orig.) [de

Momentum transfer in a Brillouin surface scattering

International Nuclear Information System (INIS)

Khater, A.F.

1980-01-01

The theory of acoustic excitation scattering in the surface of Brilloiun of opaque materials, is related to the question of momentum transfexed from radiation fields to the material when the incident eight is scattered in a measurable spectrum. (A.C.A.S.) [pt

Nonlinear behavior of stimulated scatter in large underdense plasmas

International Nuclear Information System (INIS)

Kruer, W.L.; Estabrook, K.G.

1979-01-01

Several nonlinear effects which limit Brillouin and Raman scatter of intense light in large underdense plasmas are examined. After briefly considering ion trapping and harmonic generation, we focus on the self-consistent ion heating which occurs as an integral part of the Brillouin scattering process. In the long-term nonlinear state, the ion wave amplitude is determined by damping on the heated ion tail which self-consistently forms. A simple model of the scatter is presented and compared with particle simulations. A similar model is also applied to Raman scatter and compared with simulations. Our calculations emphasize that modest tails on the electron distribution function can significantly limit instabilities involving electron plasma waves

MCRTOF, Multiple Scattering of Resonance Region Neutron in Time of Flight Experiments

International Nuclear Information System (INIS)

Ohkubo, Mako

1984-01-01

1 - Description of program or function: Multiple scattering of neutrons in the resonance energy region impinging on a disk with an arbitrary angle. 2 - Method of solution: The Monte Carlo method is employed to simulate the path of an incident neutron in a medium for which macroscopic cross sections are determined by resonance parameters. By tracing a large number of neutrons, probabilities for capture, transmission, front-face scattering, rear-face scattering and side-face scattering are determined and printed out as function of incident neutron energy. Optionally, the distribution of capture locations in the disk can be printed. The incident neutron energy is swept to fit a situation as encountered in time-of-flight experiments. 3 - Restrictions on the complexity of the problem: The cross section file is constructed from input resonance parameters with a single- level Breit-Wigner formula. The following restrictions and simplifications apply: - The maximum number of resonances is five. - Reactions other than capture and scattering are neglected. - The angular scattering distribution in the center-of-mass system is assumed to be uniform. - Chemical binding effects are neglected

Resonant diffuse X-ray scattering from magnetic multilayers

International Nuclear Information System (INIS)

Spezzani, Carlo; Torelli, Piero; Delaunay, Renaud; Hague, C.F.; Petroff, Frederic; Scholl, Andreas; Gullikson, E.M.; Sacchi, Maurizio

2004-01-01

We have measured field-dependent resonant diffuse scattering from a magnetoresistive Co/Cu multilayer. We have observed that the magnetic domain size in zero field depends on the magnetic history of the sample. The results of the X-ray scattering analysis have been compared to PEEM images of the magnetic domains

Single and multiple electromagnetic scattering by dielectric obstacles from a resonance perspective

International Nuclear Information System (INIS)

Riley, D.J.

1987-03-01

A new application of the singularity expansion method (SEM) is explored. This application combines the classical theory of wave propagation through a multiple-scattering environment and the SEM. Because the SEM is generally considered to be a theory for describing surface currents on conducting scatters, extensions are made which permit, under certain conditions, a singularity expansion representation for the electromagnetic field scattered by a dielectric scatterer. Application of this expansion is then made to the multiple-scattering case using both single and multiple interactions. A resonance scattering tensor form is used for the SEM description which leds to an associated tensor form for the solution to the multiple-scattering problem with each SEM pole effect appearing explicitly. The coherent field is determined for both spatial and SEM parameter random variations. A numerical example for the case of an ensemble of dielectric spheres which possess frequency-dependent loss is also made. Accurate resonance expansions for the single-scattering problem are derived, and resonance trajectories based on the Debye relaxation model for the refractive index are introduced. Application of these resonance expansions is then made to the multiple-scattering results for a slab containing a distribution of spheres with varying radii. Conditions are discussed which describe when the hybrid theory is appropriate. 53 refs., 21 figs., 9 tabs

Suppression of Stimulated Brillouin Scattering in multiple-ion species inertial confinement fusion Hohlraum Plasmas

International Nuclear Information System (INIS)

Neumayer, P

2007-01-01

A long-standing problem in the field of laser-plasma interactions is to successfully employ multiple-ion species plasmas to reduce stimulated Brillouin scattering (SBS) in inertial confinement fusion (ICF) hohlraum conditions. Multiple-ion species increase significantly the linear Landau damping for acoustic waves. Consequently, recent hohlraum designs for indirect-drive ignition on the National Ignition Facility investigate wall liner material options so that the liner gain for parametric instabilities will be below threshold for the onset SBS. Although the effect of two-ion species plasmas on Landau damping has been directly observed with Thomson scattering, early experiments on SBS in these plasmas have suffered from competing non-linear effects or laser beam filamentation. In this study, a reduction of SBS scattering to below the percent level has been observed in hohlraums at Omega that emulate the plasma conditions in an indirect drive ICF experiments. These experiments have measured the laser-plasma interaction processes in ignition-relevant high-electron temperature regime demonstrating Landau damping as a controlling process for SBS. The hohlraums have been filled with various fractions of CO 2 and C 3 H 8 varying the ratio of the light (H) to heavy (C and O) ion density from 0 to 2.6. They have been heated by 14.5 kJ of 351-nm light, thus increasing progressively Landau damping by an order of magnitude at constant electron density and temperature. A delayed 351-nm interaction beam, spatially smoothed to produce a 200-(micro)m laser spot at best focus, has propagated along the axis of the hohlraum. The backscattered light, both into the lens and outside, the transmitted light through the hohlraum plasma and the radiation temperature of the hohlraum has been measured. For ignition relevant laser intensities (3-9 10 14 Wcm -2 ), we find that the SBS reflectivity scales as predicted with Landau damping from >30% to <1%. Simultaneously, the hohlraum radiation

Assessment of Coulomb shifts in nucleon scattering resonances on light nuclei at low energies

International Nuclear Information System (INIS)

Takibaev, N.Zh.; Uzakova, Zh.; Abdanova, L.

2003-01-01

The assessments of the Coulomb forces contribution to position and width of the resonances at nucleons scattering on light nuclei within low energy field are given. In particular the shifts of resonances in amplitudes arising in the processes protons scattering on light nuclei relatively neutrons scattering resonance characteristics on these nuclei are considered

Study of inelastic proton scattering at isobaric analog resonances

International Nuclear Information System (INIS)

Davis, S.L.

1974-01-01

Inelastic proton scattering at isobaric analog resonances (IAR's) was studied using the targets 138 Ba and 92 Mo. Differential cross sections and analyzing powers were measured at the 10.00, 10.63, 11.09, 11.45, and 11.70 MeV resonances in 138 Ba + p and at the 5.89, 6.09, and 6.55 MeV resonances in 92 Mo + p. In addition, a new measurement, the spin flip asymmetry, was developed. The experiment was performed by using a polarized beam to make spin flip measurements. Angular distributions for the spin flip probability and spin flip asymmetry were measured at all of the above energies except for the lowest three resonances in 138 Ba, where only the spin flip probability was measured. A DWBA code modified to include the coherent addition of resonance amplitudes was used to analyze the 138 Ba data. The partial widths extracted from this analysis were converted to expansion coefficients for parent states in 139 Ba. The coefficients were found to be in good agreement with unified model calculations. For 92 Mo, inelastic polarizations, deduced from the spin flip and spin flip asymmetry, were found to be large. Attempts using Hauser Feshbach theory to describe both the cross section and polarization data repeatedly failed for both the 6.55 and 5.87 MeV IAR's. This failure represents strong evidence that Hauser Feshbach theory is not valid when extended to describe scattering at an IAR. The 92 Mo data were analyzed using a reaction theory modified to include channel-channel correlations. This theory predicts that the enhanced compound scattering is identical to the resonance scattering. Good fits have been obtained with the use of this modified Hauser Feshbach theory. (U.S.)

All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

NARCIS (Netherlands)

Offerhaus, Herman L.; Godfried, Herman; Godfried, H.P; Witteman, W.J.

1996-01-01

At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200

Pilot study on rugged fiber optic brillouin sensors for large-strain measurements to ensure the safety of transportation structures.

Science.gov (United States)

2012-07-01

Brillouin-scattering Optical Time Domain Reflectometry (BOTDR) is a viable technology for simultaneous, distributed : strain and temperature measurements for miles-long transportation structures. It is a promising tool to ensure the smooth : operatio...

Pygmy resonances probed with electron scattering

International Nuclear Information System (INIS)

Bertulani, C.A.

2007-01-01

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

Analysis and characterization. Nuclear resonant scattering with the synchrotron radiation

International Nuclear Information System (INIS)

Ruffer, R.; Teillet, J.

2003-01-01

The nuclear resonant scattering using the synchrotron radiation combines the uncommon properties of the Moessbauer spectroscopy and those of the synchrotron radiation. Since its first observation in 1984, this technique and its applications have been developed rapidly. The nuclear resonant scattering is now a standard technique for all the synchrotron radiation sources of the third generation. As the Moessbauer spectroscopy, it is a method of analysis at the atomic scale and a non destructive method. It presents the advantage not to require the use of radioactive sources of incident photons which can be difficult to make, of a lifetime which can be short and of an obviously limited intensity. The current applications are the hyperfine spectroscopy and the structural dynamics. In hyperfine spectroscopy, the nuclear resonant scattering can measure the same size than the Moessbauer spectroscopy. Nevertheless, it is superior in the ranges which exploit the specific properties of the synchrotron radiation, such as the very small samples, the monocrystals, the measures under high pressures, the geometry of small angle incidence for surfaces and multilayers. The structural dynamics, in a time scale of the nanosecond to the microsecond can be measured in the temporal scale. Moreover, the nuclear inelastic scattering gives for the first time a tool which allows to have directly the density of states of phonons and then allow to deduce the dynamical and thermodynamical properties of the lattice. The nuclear resonant scattering technique presented here, which corresponds to the Moessbauer spectroscopy technique (SM), is called 'nuclear forward scattering' (NFS). Current applications in physics and chemistry are develop. The NFS is compared to the usual SM technique in order to reveal its advantages and disadvantages. (O.M.)

Theory of inelastic effects in resonant atom-surface scattering

International Nuclear Information System (INIS)

Evans, D.K.

1983-01-01

The progress of theoretical and experimental developments in atom-surface scattering is briefly reviewed. The formal theory of atom-surface resonant scattering is reviewed and expanded, with both S and T matrix approaches being explained. The two-potential formalism is shown to be useful for dealing with the problem in question. A detailed theory based on the S-matrix and the two-potential formalism is presented. This theory takes account of interactions between the incident atoms and the surface phonons, with resonant effects being displayed explicitly. The Debye-Waller attenuation is also studied. The case in which the atom-surface potential is divided into an attractive part V/sub a/ and a repulsive part V/sub r/ is considered at length. Several techniques are presented for handling the scattering due to V/sub r/, for the case in which V/sub r/ is taken to be the hard corrugated surface potential. The theory is used to calculate the scattered intensities for the system 4 He/LiF(001). A detailed comparison with experiment is made, with polar scans, azimuthal scans, and time-of-flight measurements being considered. The theory is seen to explain the location and signature of resonant features, and to provide reasonable overall agreement with the experimental results

Multiwavelength ytterbium-Brillouin random Rayleigh feedback fiber laser

Science.gov (United States)

Wu, Han; Wang, Zinan; Fan, Mengqiu; Li, Jiaqi; Meng, Qingyang; Xu, Dangpeng; Rao, Yunjiang

2018-03-01

In this letter, we experimentally demonstrate the multiwavelength ytterbium-Brillouin random fiber laser for the first time, in the half-open cavity formed by a fiber loop mirror and randomly distributed Rayleigh mirrors. With a cladding-pumped ytterbium-doped fiber and a long TrueWave fiber, the narrow linewidth Brillouin pump can generate multiple Brillouin Stokes lines with hybrid ytterbium-Brillouin gain. Up to six stable channels with a spacing of about 0.06 nm are obtained. This work extends the operation wavelength of the multiwavelength Brillouin random fiber laser to the 1 µm band, and has potential in various applications.

Quantum multiple scattering: Eigenmode expansion and its applications to proximity resonance

International Nuclear Information System (INIS)

Li Sheng; Heller, Eric J.

2003-01-01

We show that for a general system of N s-wave point scatterers, there are always N eigenmodes. These eigenmodes or eigenchannels play the same role as spherical harmonics for a spherically symmetric target--they give a phase shift only. In other words, the T matrix of the system is of rank N, and the eigenmodes are eigenvectors corresponding to nonzero eigenvalues of the T matrix. The eigenmode expansion approach can give insight to the total scattering cross section; the position, width, and superradiant or subradiant nature of resonance peaks; the unsymmetric Fano line shape of sharp proximity resonance peaks based on the high-energy tail of a broadband; and other properties. Off-resonant eigenmodes for identical proximate scatterers are approximately angular-momentum eigenstates

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

Science.gov (United States)

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.

Light scattering by surface phonons in crystals

International Nuclear Information System (INIS)

Albuquerque, D.L.

1980-01-01

Theory of inelastic light scattering by surface acoustic phonons homogeneous crystals is presented. The Green functions are determined by the use of a classical linear response method and used to evaluate the Brillouin cross section. The acoustic modes are found from solutions to the acoustical-wave equation and boundary conditions appropriated. Two light-scattering mechanisms, amely the surface corrugation and bulk elasto-optic effect are analyzed by deriving optical fields which satisfy both the acousto-optically driven wave equation and the electromagnetic boundary conditions. No restrictions are imposed concerning the angle of incidence of the light. Some representative computed Brillouin ineshapes are also presented and their features discussed. (author) [pt

Anomalous couplings, resonances and unitarity in vector boson scattering

Energy Technology Data Exchange (ETDEWEB)

Sekulla, Marco

2015-12-04

The Standard Model of particle physics has proved itself as a reliable theory to describe interactions of elementary particles. However, many questions concerning the Higgs sector and the associated electroweak symmetry breaking are still open, even after (or because) a light Higgs boson has been discovered. The 2→2 scattering amplitude of weak vector bosons is suppressed in the Standard Model due to the Higgs boson exchange. Therefore, weak vector boson scattering processes are very sensitive to additional contributions beyond the Standard Model. Possible new physics deviations can be studied model-independently by higher dimensional operators within the effective field theory framework. In this thesis, a complete set of dimension six and eight operators are discussed for vector boson scattering processes. Assuming a scenario where new physics in the Higgs/Goldstone boson decouples from the fermion-sector and the gauge-sector in the high energy limit, the impact of the dimension six operator L{sub HD} and dimension eight operators L{sub S,0} and L{sub S,1} to vector boson scattering processes can be studied separately for complete processes at particle colliders. However, a conventional effective field theory analysis will violate the S-matrix unitarity above a certain energy limit. The direct T-matrix scheme is developed to allow a study of effective field theory operators consistent with basic quantum-mechanical principles in the complete energy reach of current and future colliders. Additionally, this scheme can be used preventively for any model, because it leaves theoretical predictions invariant, which already satisfies unitarity. The effective field theory approach is further extended by allowing additional generic resonances coupling to the Higgs/Goldstone boson sector, namely the isoscalar-scalar, isoscalar-tensor, isotensor-scalar and isotensor-tensor. In particular, the Stueckelberg formalism is used to investigate the impact of the tensor degree of

Pion-nucleus scattering around the (3,3) resonance

International Nuclear Information System (INIS)

Rahman, M.A.; Sen Gupta, H.M.; Rahman, M.

1989-09-01

Elastic scattering of π ± are studied on 28 Si, 40 Ar, 40,48 Ca, 90 Zr and 208 Pb at energies around the (3,3) resonance within the framework of the strong absorption model of Frahn and Venter. The parameters thus obtained are used in the analysis of the inelastic scattering of pions leading to the lowest 2 ± state in 28 Si. A reasonably good account of the scattering processes (elastic and inelastic) is given by the simple model. (author). 13 refs, 8 figs, 3 tabs

Chemical shift of neutron resonances and some ideas on neutron resonances and scattering theory

International Nuclear Information System (INIS)

Ignatovich, V.K.; )

2002-01-01

The dependence of positions of neutron resonances in nuclei in condensed matter on chemical environment is considered. A possibility of theoretical description of neutron resonances, different from R-matrix theory is investigated. Some contradictions of standard scattering theory are discussed and a new approach without these contradictions is formulated [ru

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

Directory of Open Access Journals (Sweden)

Xiaoyi Bao

2013-01-01

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

Phase-conjugate resonant holographic interferometry applied to NH concentration measurements in a 2D diffusion flame

Energy Technology Data Exchange (ETDEWEB)

Tzannis, A P; Beaud, P; Frey, H M; Gerber, T; Mischler, B; Radi, P P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Resonant Holographic Interferometry is a method based on the anomalous dispersion of light having a frequency close to an electronic transition of a molecule. We propose a novel single-laser, two-colour setup for recording resonant holograms and apply it to 2D species concentration measurements. The second colour is generated by optical phase-conjugation from Stimulated Brillouin scattering in a cell. Phase-Conjugate Resonant Holographic Interferometry (PCRHI) is demonstrated in a 2D NH{sub 3}/O{sub 2} flame yielding interferograms that contain information on the NH radical distribution in the flame. Experimental results are quantified by applying a numerical computation of the Voigt profiles. (author) 1 fig., 3 refs.

Resonance proton scattering use for the beam parameters control of the electrostatic accelerator

Directory of Open Access Journals (Sweden)

V. I. Soroka

2013-12-01

Full Text Available The paper discusses peculiarities of the resonance proton scattering use for the beam parameters control of the electrostatic accelerators. The expediency of the use has been confirmed by experiment. Peculiarities are caused because elastic resonance scattering through the stage of compound nucleus is always accompanied by potential and Coulomb scattering. These three components interfere and for that reason the resonance form de-pends on a scattering angle and total angular moment of a compound nucleus level. However, possessing neces-sary information in the given field of nuclear spectroscopy enables the selection of resonance with the character-istics suitable for the calibration purpose. Considerable increase of the scattering cross section in the resonance region saves the time and simplifies the experiment technical maintenance. The experiments were performed at the 10 MeV tandem accelerator of the Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, after its modernization. Silicon and oxygen were used as the targets. Silicon targets were of two types of thickness: 1 the target of complete absorption, 2 the target with the thickness in which the loss of protons ener-gy exceeded the width of the selected resonance. The elastic and non elastic scattering from silicon were used in region of the 3,100 MeV proton energy resonance. Oxygen target, as component of the surface oxidizing layer on beryllium had the thickness which in terms of the loss of proton energy was less than the width of the selected elastic narrow resonance at 3,470 MeV proton energy. As result of the measurement the corrections concerning the energy scale of the accelerator and protons energy spread in the beam were proposed.

Investigation of collective excitations in fluid neon by coherent neutron scattering at small scattering vectors

International Nuclear Information System (INIS)

Bell, H.G.

1976-07-01

The energy spectra of Ne studied under different temperatures and pressures with the aid of inelastic, coherent neutron scattering can be described by a scattering law derived from the basic hydrodynamic equations. The Brillouin lines found with very small momentum transfer 0.06 A -1 -1 are interpreted as collective, adiabatic pressure fluctuations. (orig./WL) [de

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

Directory of Open Access Journals (Sweden)

ANDRÉ G. SIMÃO

2016-06-01

Full Text Available Abstract 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.

Localized spin-wave modes in a triangular magnetic element studied by micro-focused Brillouin light scattering

Energy Technology Data Exchange (ETDEWEB)

Hwang, S.; Kwon, J.-H. [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Grünberg, P. [Grünberg Center for Magnetic Nanomaterials, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Cho, B.K., E-mail: chobk@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of)

2017-09-01

Highlights: • Direct evidence of localized mode in a triangular nano-magnet using μ-BLS. • Localized regions are identified by the internal field distribution. • The spatially resolved measurement was performed to obtain 2-D intensity map. • Spin modes in same positions can be distinguish comparing with simulated spectrum. • Localized modes were identified by comparing with the simulated spatial profiles. - Abstract: Localized spin-wave modes, which were thermally excited at a specific position in a triangular magnetic element, were investigated using micro-focused Brillouin light scattering in two saturated states, the buckle and Y-states, with an applied magnetic field of 0.24 T parallel and perpendicular to the basal edge, respectively. The measured frequency spectrum at a specific beam spot position, rather than an integrated spectrum, was analyzed by comparing it with the simulation data at a precisely selected position within the beam spot area. The analyzed results were used to plot a two-dimensional intensity map and simulation spatial profile to verify the validity of the analysis. From the analysis process, two localized spin-wave modes in a triangular magnetic element were successfully identified near the apex region in the buckle state and near the basal edge region in the Y-state.

Resonant scattering in the presence of an electromagnetic field

International Nuclear Information System (INIS)

Rosenberg, L.

1983-01-01

The theory of resonant reactions, in the projection-operator formulation of Feshbach, is generalized to account for the presence of an external electromagnetic field. The theory is used as the basis for the construction of low-frequency approximations for the transition amplitude. Results obtained here for scattering in a laser field confirm earlier versions of the low-frequency approximation when the resonances are isolated. However, if there are several closely spaced resonances additional terms must be included (their importance magnified by the appearance of near singularities) which account for the effect of radiative transitions between pairs of nearly degenerate resonant states. The weak-field limit of this result yields a low-frequency approximation for single-photon spontaneous bremsstrahlung which, through the inclusion of correction terms associated with closely spaced resonances, provides an improvement over the Feshbach-Yennie version derived some time ago. A separate treatment is required to deal with the limiting case of a static external field and this is worked out here in the context of a time-dependent formulation of the scattering problem. Linear and quadratic Stark splitting of the resonance positions, and resonance broadening due to the tunneling mechanism, are expected to play a significant role in the static limit and these effects are included in the approximation derived here for the transition amplitude

Light scattering by surface phonons in crystals

International Nuclear Information System (INIS)

Albuquerque, E.L. de

1981-01-01

A theory of inelastic light scattering by surface acoustic phonons in homogeneous crystals is presented. The Green functions are determined by the use of a classical linear response method and used to evaluate the Brillouin cross section. The acoustic modes are found from solutions to the acoustical-wave equation and boundary conditions appropriated. Two light-scattering mechanisms, namely the surface corrugation and bulk elasto-optic effect are analyzed by deriving optical fields which satisfy both the acousto-optically driven wave equation and the electromagnetic boundary conditions. No restrictions are imposed concerning the angle of incidence of the light. Some representative computed Brillouin lineshapes are also presented and their features discussed. (Author) [pt

Proton compton scattering in the resonance region

International Nuclear Information System (INIS)

Ishii, Takanobu.

1979-12-01

Differential cross sections of the proton Compton scattering have been measured in the energy range between 400 and 1150 MeV at CMS angles of 130 0 , 100 0 and 70 0 . The recoil proton was detected with a magnetic spectrometer using multi-wire proportional chambers and wire spark chambers. In coincidence with the proton, the scattered photon was detected with a lead glass Cerenkov counter of the total absorption type with a lead plate converter, and horizontal and vertical scintillation counter hodoscopes. The background due to the neutral pion photoproduction, was subtracted by using the kinematic relations between the scattered photon and the recoil proton. Theoretical calculations based on an isobar model with two components, that is, the resonance plus background, were done, and the photon couplings of the second resonance region were determined firstly from the proton Compton data. The results are that the helicity 1/2 photon couplings of P 11 (1470) and S 11 (1535), and the helicity 3/2 photon coupling of D 13 (1520) are consistent with those determined from the single pion photoproduction data, but the helicity 1/2 photon coupling of D 13 (1520) has a somewhat larger value than that from the single pion photoproduction data. (author)

Surface Brillouin scattering measurement of the elastic constants of single crystal InAs{sub 0.91}Sb{sub 0.09}

Energy Technology Data Exchange (ETDEWEB)

Kotane, L M; Comins, J D; Every, A G [Materials Physics Research Institute, School of Physics, University of the Witwatersrand, Johannesburg, Wits 2050 (South Africa); Botha, J R, E-mail: Lesias.Kotane@wits.ac.z [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

2011-01-01

Surface Brillouin scattering of light has been used to measure the angular dependence of the Rayleigh surface acoustic wave (SAW), pseudo surface acoustic wave (PSAW) and longitudinal lateral wave (LLW) speeds in a (100)-oriented single crystal of the ternary semiconductor alloy InAs{sub 0.91}Sb{sub 0.09}. The wave speed measurements have been used to determine the room temperature values of the elastic constants C{sub 11}, C{sub 12} and C{sub 44} of the alloy. A simple and robust fitting procedure has been implemented for recovering the elastic constants, in which the merit function is constructed from explicit secular functions that determine the surface and lateral wave speeds in the [001] and [011] crystallographic directions. In the fitting, relatively larger weighting factors have been assigned to the SAW and PSAW data because of the greater precision with which the surface modes can be measured as compared with the lateral wave.

Time-domain, nuclear-resonant, forward scattering: the classical approach

International Nuclear Information System (INIS)

Hoy, G.R.

1997-01-01

This paper deals with the interaction of electromagnetic radiation with matter assuming the matter to have nuclear transitions in resonance with incident electromagnetic radiation. The source of the radiation is taken to be of two types; natural radioactive gamma decay and synchrotron radiation. Numerical examples using 57 Fe are given for the two types of source radiation. Calculated results are contrasted for the two cases. Electromagnetic radiation produced by recoil-free gamma-ray emission has essentially the natural linewidth. Electromagnetic radiation from a synchrotron, even with the best monochromators available, has a relatively broad-band spectrum, essentially constant for these considerations. Polarization effects are considered. In general, the nuclear-resonant medium changes the polarization of the input radiation on traversing the medium. Calculations are presented to illustrate that synchrotron radiation studies using nuclear-resonant forward scattering have the potential for making high-precision measurements of hyperfine fields and recoilless fractions. An interesting aspect of nuclear-resonant forward scattering, relative to possible gamma-ray laser development, is the so-called 'speed-up' effect

Resonant scattering on impurities in the quantum Hall effect

International Nuclear Information System (INIS)

Gurvitz, A.

1994-06-01

We developed a new approach to carrier transport between the edge states via resonant scattering on impurities, which is applicable both for short and long range impurities. A detailed analysis of resonant scattering on a single impurity is performed. The results used for study of the inter-edge transport by multiple resonant hopping via different impurities' site. We found the total conductance can be obtained from an effective Schroedinger equation with constant diagonal matrix elements in the Hamiltonian, where the complex non-diagonal matrix elements are the amplitudes of a carrier hopping between different impurities. It is explicitly shown how the complex phase leads to Aharonov-Bohm oscillations in the total conductance. Neglecting the contribution of self-crossing resonant-percolation trajectories, we found that the inter-edge carrier transport is similar to propagation in one-dimensional system with off-diagonal disorder. Then we demonstrated that each Landau band has an extended state Ε Ν , while all other states are localized, and the localization length behaves as L - 1 Ν (Ε) ∼ (Ε - Ε Ν ) 2 . (author)

Resonance effects in neutron scattering lengths

Energy Technology Data Exchange (ETDEWEB)

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.

Resonance effects in neutron scattering lengths

International Nuclear Information System (INIS)

Lynn, J.E.

1989-01-01

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

Four-nucleon problem in terms of scattering of Hilbert-Schmidt resonances

International Nuclear Information System (INIS)

Narodetsky, I.M.

1974-01-01

The four-body integral equations are written in terms of the scattering amplitudes for the Hilbert-Schmidt resonances corresponding to the 3*1 and 2*2 subsystems. As a result, the four-body problem is reduced to the many channel two-body problem. A simple diagram technique is introduced which is the generalization of the usual time-ordered nonrelativistic one. The connection between the amplitudes of the two-body reactions and the scattering amplitudes for the resonances is obtained

X-ray resonant Raman scattering cross sections of Mn, Fe, Cu and Zn

International Nuclear Information System (INIS)

Sanchez, Hector Jorge; Valentinuzzi, MarIa Cecilia; Perez, Carlos

2006-01-01

X-ray fluorescence spectra present singular characteristics produced by the different scattering processes. When atoms are irradiated with incident energy lower and close to an absorption edge, scattering peaks appear due to an inelastic process known as resonant Raman scattering. It constitutes an important contribution to the background of the fluorescent line. The resonant Raman scattering must be taken into account in the determination of low concentration contaminants, especially when the elements have proximate atomic numbers. The values of the mass attenuation coefficients experimentally obtained when materials are analysed with monochromatic x-ray beams under resonant conditions differ from the theoretical values (between 5% and 10%). This difference is due, in part, to the resonant Raman scattering. Monochromatic synchrotron radiation was used to study the Raman effect on pure samples of Mn, Fe, Cu and Zn. Energy scans were carried out in different ranges of energy near the absorption edge of the target element. As the Raman peak has a non-symmetric shape, theoretical models for the differential cross section, convoluted with the instrument function, were used to determine the RRS cross section as a function of the incident energy

Soft X-ray resonant scattering from magnetic heterostructures

International Nuclear Information System (INIS)

Grabis, J.

2005-01-01

Heterogenous magnetic multilayers are of great interest both because of their relevance for technological applications and since they provide model systems to understand magnetic behavior and interactions. Soft x-ray resonant magnetic scattering (XRMS) allows to determine element-specific and depth-resolving information of the local magnetic order of such systems. Within the framework of the present thesis the diffractometer ALICE for soft XRMS has been constructed. XRMS measurements of two different physical systems are presented in this thesis: The antiferromagnetic and ferromagnetic order in interlayer exchange-coupled Fe/Cr(001) superlattices are studied as a function of the applied field by measuring the reflected intensity at different positions in reciprocal space. Thin films and multilayers of the Heusler compound Co 2 MnGe are studied by means of soft x-ray absorption spectroscopy, magnetic circular dichroism and resonant magnetic scattering

New physics/resonances in vector boson scattering at the LHC

International Nuclear Information System (INIS)

Reuter, Juergen; Kilian, Wolfgang; Ohl, Thorsten; Sekulla, Marco

2016-05-01

Vector boson scattering is (together with the production of multiple electroweak gauge bosons) the key process in the current run 2 of LHC to probe the microscopic nature of electroweak symmetry breaking. Deviations from the Standard Model are generically parameterized by higher-dimensional operators, however, there is a subtle issue of perturbative unitarity for such approaches for the process above. We discuss a parameter-free unitarization prescription to get physically meaningful predictions. In the second part, we construct simplified models for generic new resonances that can appear in vector boson scattering, with a special focus on the technicalities of tensor resonances.

Advances in gamma ray resonant scattering and absorption long-lived isomeric nuclear states

CERN Document Server

Davydov, Andrey V

2015-01-01

This book presents the basics and advanced topics of research of gamma ray physics. It describes measuring of  Fermi surfaces with gamma resonance spectroscopy and the theory of angular distributions of resonantly scattered gamma rays. The dependence of excited-nuclei average lifetime on the shape of the exciting-radiation spectrum and electron binding energies in the spectra of scattered gamma rays is described. Resonant excitation by gamma rays of nuclear isomeric states with long lifetime leads to the emission and absorption lines. In the book, a new gamma spectroscopic method, gravitational gamma spectrometry, is developed. It has a resolution hundred million times higher than the usual Mössbauer spectrometer. Another important topic of this book is resonant scattering of annihilation quanta by nuclei with excited states in connection with positron annihilation. The application of the methods described is to explain the phenomenon of Coulomb fragmentation of gamma-source molecules and resonant scatt...

Resonance electronic Raman scattering in rare earth crystals

International Nuclear Information System (INIS)

Williams, G.M.

1988-01-01

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 3+ (4f 1 ) in single crystals of LuPO 4 and Er 3+ (4f 11 ) in single crystals of ErPO 4 . 134 refs., 92 figs., 33 tabs

Experimental investigation of quantum effects in time-resolved resonance Rayleigh scattering from quantum well excitons

DEFF Research Database (Denmark)

Birkedal, Dan; Shah, Jagdeep; Shchegrov, Andrei V.

2000-01-01

Resonant Rayleigh scattering from quantum well excitons is investigated using ultrafast spectral interferometry. We isolate the coherent Rayleigh scattering from incoherent luminescence in a single speckle. Averaging the resonant Rayleigh intensity over several speckles allows us to identify...... features in support of quantum corrections to the classical description of the underlying scattering process....

Path-integral approach to resonant electron-molecule scattering

International Nuclear Information System (INIS)

Winterstetter, M.; Domcke, W.

1993-01-01

A path-integral formulation of resonant electron-molecule scattering is developed within the framework of the projection-operator formalism of scattering theory. The formation and decay of resonances is treated in real time as a quantum-mechanical electronic-tunneling process, modified by the coupling of the electronic motion with the nuclear degrees of freedom. It is shown that the electronic continuum can be summed over in the path-integral formulation, resulting formally in the path integral for an effective two-state system with coupling to vibrations. The harmonic-oscillator approximation is adopted for the vibrational motion in the present work. Approximation methods are introduced which render the numerical evaluation of the sum over paths feasible for up to ∼10 3 elementary time slices. The theory is numerically realized for simple but nontrivial models representing the 2 Π g d-wave shape resonance in e - +N 2 collisions and the 2 Σ u + p-wave shape resonance in e - +H 2 collisions, respectively. The accuracy of the path-integral results is assessed by comparison with exact numerical reference data for these models. The essential virtue of the path-integral approach is the fact that the computational effort scales at most linearly with the number of vibrational degrees of freedom. The path-integral method is thus well suited to treat electron collisions with polyatomic molecules and molecular aggregates

Dichroism in resonant inelastic soft X-ray scattering

International Nuclear Information System (INIS)

Braicovich, L.

2004-01-01

Full text: The dichroism (and in particular the magnetic dichroism) has emerged in the last decade as a key method in the study of electronic states in solids. This has been largely due to the exploitation of the modern sources of Synchrotron Radiation. This approach has been extensively used in X ray Absorption Spectroscopy i.e. in a first order process giving a straightforward access, trough sum rules, to the ground state properties of the sample. On the other hand the studies of dichroism in second order processes as the photon scattering experiments has been up to now relatively limited probably due to experimental difficulties. This is too bad because, at least in principle, the scattering experiments offer unique opportunities typical of second order processes, beyond the possibilities offered by absorption spectroscopy. This requires specific scattering experiments able to give information that cannot be obtained in the absorption mode. A typical example is the circular magnetic dichroism in resonant inelastic scattering in perpendicular geometry i.e. with the light incident perpendicular to the magnetisation. In this case the circular dichroism in absorption is zero by symmetry while the detection of the scattered photons at an angle breaks the left-right symmetry and allows a dichroism to be observed. The aim of the present talk is to review critically the dichroism in resonant X-ray scattering and to show the potential of this approach. In particular it will be shown how to recover, in magnetic samples, the ground state information up to the moments of order four. In this connection original results will be presented including the demonstration of a new experimental approach. The perspectives of the field will be also discussed

High resolution resonant Raman scattering in InP and GaAs

International Nuclear Information System (INIS)

Kernohan, E.T.M.

1996-04-01

Previous studies of III-V semiconductors using resonant Raman scattering have concentrated on measuring the variations in scattering intensity under different excitation conditions. The shape of the Raman line also contains important information, but this has usually been lost because the low signal strengths mean that resolution has been sacrificed for sensitivity. It might therefore be expected that further insights into the processes involved in Raman scattering could be obtained by using high resolution methods. In this thesis I have measured single- and multiple- phonon scattering from bulk GaAs and InP with a spectral resolution better than the intrinsic widths of the Raman lines. For scattering in the region of one longitudinal optic (LO) phonon energy, it is found that in InP the scattering in the allowed and forbidden configurations occur at different Raman shifts, above and below the zone-centre phonon energy respectively. These shifts are used to determine the scattering processes involved, and how they differ between InP and GaAs. The lineshapes obtained in multiple-phonon scattering are found to depend strongly on the excitation energy used, providing evidence for the presence of intermediate resonances. The measured spectra are used to provide information about the phonon dispersion of InP, whose dispersion it is difficult to measure in any other way, and the first evidence is found for an upward dispersion of the LO mode. Raman lineshapes are measured for InP in a magnetic field. The field alters the electronic bandstructure, leading to a series of strong resonances in the Raman efficiency due to interband magneto-optical transitions between Landau levels. This allows multiphonon processes up to sixth-order to be investigated. (author)

Stimulated Brillouin backscattering and magnetic field generation in laser-produced plasmas

International Nuclear Information System (INIS)

Bawa'aneh, M.S.

1999-01-01

This thesis is concerned with aspects of laser-plasma interactions related to fusion reactions; in particular thermoelectric magnetic field generation around a hole dug in plasma by intense laser beams, and stimulated Brillouin back scattering (SBBS) from plasmas containing hot spots. A hole, of the size of the laser focal spot, is dug in the plasma when illuminated by intense laser if the laser pressure exceeds the plasma thermal pressure. This hole is found to have steep, radial density gradients. My first concern arose from the prediction that magnetic fields might be generated around the hole-plasma interface in places where the steep density gradients overlap with the non-aligned temperature gradients. When a high-power laser beam is focused on a solid pellet, plasma is formed at the surface. In order to create conditions for thermonuclear reactions in the interior of the pellet, an effective deposition of the laser energy to thermal energy of the pellet via laser-plasma coupling is necessary. When light irradiates a plasma collective processes occur, which can either enhance or reduce the light absorption. For a better understanding of the fusion problem a knowledge of the nature of these collective processes and of the fraction of light reflected from the plasma modes is required. Local hot spots seen experimentally lead to higher gain levels of scattered light. These local temperature inhomogeneities could lead to non-equilibrium distributions, which result in a free energy leading to some interesting phenomena in plasma. In the second part of the thesis stimulated Brillouin back scattering from an ion acoustic mode in a hot spot is studied. Temperature inhomogeneities lead to an ion acoustic instability, and to higher levels of SBBS gain, which leads to lower thresholds for the same electron to ion temperature ratios. This could be the answer for the observed high levels of scattering from hot spots. (author)

Hadron scattering, resonances, and QCD

Science.gov (United States)

Briceño, R. A.

2016-11-01

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.

Experimental elucidation: microscopic mechanism of resonant X-ray scattering in manganite films

CERN Document Server

Ohsumi, H; Kiyama, T

2003-01-01

Resonant X-ray scattering experiments have been performed on perovskite manganite La sub 0 sub . sub 5 Sr sub 0 sub . sub 5 MnO sub 3 thin films, which are grown on three distinct perovskite with a coherent epitaxial strain and have a forced ferro-type orbital ordering of Mn 3d orbitals. Using an interference technique, we have successfully observed the resonant X-ray scattering signal from the system having the ferro-type orbital ordering and also revealed the energy scheme of Mn 4p bands. For the forced ferro-type orbital ordering system, the present results evidence that the resonant X-ray scattering signal originates from the band structure effect due to the Jahn-Teller distortion of a MnO sub 6 octahedron, and not from the Coulomb interaction between 3d and 4p electrons. (author)

Acoustic resonance scattering from a multilayered cylindrical shell with imperfect bonding.

Science.gov (United States)

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.

Interior and exterior resonances in acoustic scattering. pt. 2 - Targets of arbitrary shape (T-matrix approach)

International Nuclear Information System (INIS)

Uberall, H.; Gaunaurd, G.C.; Tanglis, E.

1983-01-01

The T-matrix approach, which describes the scattering of acoustic waves (or of other waves) from objects of arbitrary shape and geometry, is here 'married' to the resonance scattering theory in order to obtain the (complex) resonance frequencies of an arbitrary shaped target. For the case of nearly impenetrable targets the partial-wave scattering amplitudes are splitted into terms corresponding to 'internal' resonances, plus an apparently nonresonant background amplitude which, however, contains the broad resonances caused by 'external' diffracted (or Franz-type, creeping) waves, in addition to geometrically reflected and refracted (ray) contributions

Excitation of giant resonances through inelastic scattering

International Nuclear Information System (INIS)

Kailas, S.

1981-01-01

In the last few years, exciting developments have taken place in the study of giant resonances (GR). In addition to the already well known gjant dipole resonance (GDR), the presence of at least two more new GRs viz. giant quadrupole resonance (GQR) and giant monopole resonance (GMR) has been experimentally established. The systematics covering these GRs is found to be consistent with the theoretical expectation. Though the existence of higher multipoles has been predjcted by theory, so far only some of these have been found to be excited experimentally. Various probe particles - electrons, protons (polarized and unpolarized), light and heavy ions and pions - at different bombarding energies have been used to excite the GR region, primarily through the inelastic scattering process. Detailed experiments, looking at the decay modes of GR region, have also been performed. These studies have contributed significantly to a better understanding of the phenomenon of nuclear collective excitation. In this report, the current status of 'GR' research is reviewed. (author)

The interpretation of the intensity of components of laser scattering by interaction with matter

Science.gov (United States)

Fidanovski, Z.; Srećković, M.; Ostojić, S.; Ilić, J.; Merkle, M.

2012-05-01

The measurement of scattered light properties offers many optical, acoustic, dielectric, thermodynamic data about the scattering medium. Brillouin spectroscopy with various modifications and different laser types has been a measurement technique in acoustics for a long time, but it is still important as an autonomous technique. It enables more detailed and exhaustive knowledge of the acoustic and optical properties of matter. A series of Rayleigh-Brillouin spectra are recorded for a set of organic solvents and phytol. The equipment used in spectra recordings enables the measurement of four components of scattered laser intensity Ihh, Ihv, Ivv and Ivh. The ratios of the linewidth, as well as shifts, are determined for Rayleigh-Brillouin spectra. According to them, the hypersound velocity and absorption coefficients can be calculated. There is much software for data processing obtained in laser interaction with matter, with different programming tools. An analysis of spectra is performed, i.e. an examination of which distribution (Gaussian or Lorentzian) better explains the experimentally obtained diagrams.

High-temperature Brillouin scattering study of haplogranitic glasses and liquids: Effects of F, K, Na and Li on Tg and elastic properties

Science.gov (United States)

Manghnani, M. H.; Hushur, A.; Williams, Q. C.; Dingwell, D. B.

2010-12-01

The density, compressibility and viscosity of silicate melts are important in understanding the thermodynamic and fluid dynamic properties of magmatic systems. Knowledge of the compressibility of silicate melts at 1 bar is an important component in the construction of accurate pressure-volume-temperature equations of state. In light of this, the velocity (nVp, Vp, Vs) and refractive index n of four anhydrous haplogranitic glasses and liquids with similar alkali abundances, but different cations, are measured at high temperature by Brillouin scattering spectroscopy through the glass transition temperature (Tg) in both platelet and back scattering geometry. The compositions of four haplogranites are 5 wt% of the components Li2O, Na2O, K2O and F each added to a base of haplogranitic (HPG8) composition. The glass transition temperature Tg of different haplogranite samples at the GHz frequency of the Brillouin probe are determined from the change in slope of the temperature-dependent longitudinal or transverse sound velocity. HPG8-Li5 has the lowest glass transition temperature (466°C), while HPG8-K5 has the highest glass transition temperature (575°C). Our Brillouin results, when compared with DSC measurements, show lower Tg values. This raises the possibility of a role of either heating rates or a frequency dependence of the glass transition in explaining the discrepancies in Tg values derived from the two methods. The sound velocity (nVp, Vp, Vs) shows markedly different temperature dependences (including differences in sign) below Tg depending on their different alkali contents. The unrelaxed elastic moduli of three haplogranitic glasses with added Li2O, Na2O and F components have been obtained as a function of temperature. The unrelaxed bulk modulus, shear modulus and Poisson’s ratio show strong compositional dependences at ambient temperature. On heating, The K initially decreases with increasing temperature up to ~ 135°C, then increases up to Tg, and then

The disorder-induced Raman scattering in Au/MoS{sub 2} heterostructures

Energy Technology Data Exchange (ETDEWEB)

Gołasa, K., E-mail: Katarzyna.Golasa@fuw.edu.pl; Grzeszczyk, M.; Binder, J.; Bożek, R.; Wysmołek, A.; Babiński, A. [Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa (Poland)

2015-07-15

The Raman scattering has been studied in heterostructures composed of a thin MoS{sub 2} flake and a 1-1.5 nm layer of thermally evaporated gold (Au). There have been Au nanoislands detected in the heterostructure. It has been found that their surface density and the average size depend on the MoS{sub 2} thickness. The Raman scattering spectrum in the heterostructure with a few monolayer MoS{sub 2} only weakly depends on the excitation (resonant vs. non-resonant) mode. The overall Raman spectrum corresponds to the total density of phonon states, which is characteristic for disordered systems. The disorder in the MoS{sub 2} layer is related to the mechanical strain induced in the MoS{sub 2} layer by the Au nanoislands. The strain results in the localization of phonon modes, which leads to the relaxation of the momentum conservation rule in the scattering process. The relaxation allows phonons from the whole MoS{sub 2} Brillouin zone to interact with electronic excitations. Our results show that the Au nanoislands resulted from thermal evaporation of a thin metal layer introduce substantial disorder into the crystalline structure of the thin MoS{sub 2} layers.

Theoretical evaluation of self-shielding factors due to scattering resonances in foils

International Nuclear Information System (INIS)

Selander, W.N.

1960-06-01

A semi-analytical method is given for evaluating self-shielding factors for activation measurements which use thin foils having neutron scattering resonances. The energy loss by scattering in the foil is taken into account. The energy-dependent neutron angular distribution is expanded as a double series, the coefficients of which are (energy dependent) solutions of an infinite set of coupled integral equations. These are truncated in some suitable manner and solved numerically. The leading term of the series is proportional to the average, or effective flux in the activation sample. The product of this terra and the neutron capture cross-section is integrated numerically over the resonance to give the resonance self-shielding correction. Figure 4 shows resonance self-shielding factors derived in this mariner for the 132ev resonance in Co-59 and figure 5 shows similar results for the two Mn-55 resonances at 337ev and 1080ev. Self-shielding factors for 1/v capture are not significantly different from unity. (author)

Photon nuclear scattering on lead and bismuth in the region of the giant resonance

International Nuclear Information System (INIS)

Tamas, Gabriel.

1976-01-01

The results of monochromatic photon nuclear scattering studies on natural lead and bismuth targets are presented. The cross sections for the inelastic scattering leading to the first excited levels of 204 Pb, 206 Pb and 207 Pb are important, in agreement with theoretical predictions. The elastic scattering amplitude is related to the total photon absorption by dispersion relations. It is then possible to determine the spin of resonances excited by the reaction studied. Precise measurements carried out between 14 and 20MeV revealed that the angular distribution cannot be explained by a single dipolar resonance. A quadrupolar resonance at E 2 =14MeV must be introduced [fr

Observations of resonance-like structures for positron-atom scattering at intermediate energies

International Nuclear Information System (INIS)

Dou, L.

1993-01-01

Absolute values of elastic differential cross sections (DCS's) are measured for position (e + ) scattering by argon (8.7-300 eV) krypton (6.7-400 eV) and also neon (13.6-400 eV) using a crossed-beam experimental setup. When the DCS's are plotted at fixed scattering angles of 30 degrees, 60 degrees, 90 degrees and 120 degrees versus energy it has been found that well-defined resonance-like structures are found at an energy of 55-60 eV for argon and at 25 and 200 eV for krypton, with a broader structure found between 100-200 eV for neon. These observed resonance-like structures are unusual because they occur at energies well above the known inelastic thresholds for these atoms. They may represent examples of open-quotes coupled channel shape resonancesclose quotes, first predicted by Higgins and Burke [1] for e + -H scattering in the vicinity of 36 eV (width ∼ 4 eV), which occurs only when both the elastic and positronium formation scattering channels are considered together. A more recent e + -H calculation by Hewitt et al. [2] supports the Higgins and Burke prediction. These predictions and the present observations suggest the existence of a new type of atomic scattering resonance

Strong Three-magnon Scattering in Cuprates by Resonant X-rays

OpenAIRE

Ament, Luuk J. P.; Brink, Jeroen van den

2010-01-01

We show that Resonant Inelastic X-ray scattering (RIXS) is sensitive to three-magnon excitations in cuprates. Even if it requires three electrons to simultaneously flip their spin, the RIXS tri-magnon scattering amplitude is not small. At the Cu $L$-edge its intensity is generally larger than the bi-magnon one and at low transferred momentum even larger than the single-magnon intensity. At the copper $M$-edge the situation is yet more extreme: in this case three-magnon scattering is dominatin...

Resonant stimulation of Raman scattering from single-crystal thiophene/phenylene co-oligomers

International Nuclear Information System (INIS)

Yanagi, Hisao; Marutani, Yusuke; Matsuoka, Naoki; Hiramatsu, Toru; Ishizumi, Atsushi; Sasaki, Fumio; Hotta, Shu

2013-01-01

Amplified Raman scattering was observed from single crystals of thiophene/phenylene co-oligomers (TPCOs). Under ns-pulsed excitation, the TPCO crystals exhibited amplified spontaneous emission (ASE) at resonant absorption wavelengths. With increasing excitation wavelength to the 0-0 absorption edge, the stimulated resonant Raman peaks appeared both in the 0-1 and 0-2 ASE band regions. When the excitation wavelength coincided with the 0-1 ASE band energy, the Raman peaks selectively appeared in the 0-2 ASE band. Such unusual enhancement of the 0-2 Raman scattering was ascribed to resonant stimulation via vibronic coupling with electronic transitions in the uniaxially oriented TPCO molecules

Far-field superresolution by imaging of resonance scattering

KAUST Repository

Schuster, Gerard T.

2014-10-31

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.

Single-photon switch: Controllable scattering of photons inside a one-dimensional resonator waveguide

Science.gov (United States)

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).

Nanometer-range atomic order directly recovered from resonant diffuse scattering

Czech Academy of Sciences Publication Activity Database

Kopecký, Miloš; Kub, Jiří; Fábry, Jan; Hlinka, Jiří

2016-01-01

Roč. 93, č. 5 (2016), 1-8, č. článku 054202. ISSN 1098-0121 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : diffuse scattering * resonant scattering * atomic structure * perovskites * relaxors * PbMg 1/3 Nb 2/3 O 3 (PMN) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering

Energy Technology Data Exchange (ETDEWEB)

Gao, Xuan [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Key Laboratory of Multi-scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China); Casa, Diego; Kim, Jungho; Gog, Thomas [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Li, Chengyang [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Department of Physics, South University of Science and Technology of China, Shenzhen 518055 (China); Burns, Clement [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States)

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.

Spin asymmetry in resonant electron-hydrogen elastic scattering

International Nuclear Information System (INIS)

McCarthy, I.E.; Shang, Bo.

1993-02-01

Differential cross sections and asymmetries at 90 deg. and 30 deg are calculated for electron-hydrogen elastic scattering over the energies of the lowest 1 S and 3 P resonances using a nine-state coupled-channels calculation with and without continuum effects, which are represented by an equivalent-local polarization potential. The polarization potential improves agreement with experiment in general for the spin-averaged cross sections. It is suggested that continuum effects would be critically tested by asymmetry measurement at 30 deg over the 1 S resonance. 7 refs., 4 figs

Viscoelasticity of amyloid plaques in transgenic mouse brain studied by Brillouin microspectroscopy and correlative Raman analysis

Directory of Open Access Journals (Sweden)

Sara Mattana

2017-11-01

Full Text Available Amyloidopathy is one of the most prominent hallmarks of Alzheimer’s disease (AD, the leading cause of dementia worldwide, and is characterized by the accumulation of amyloid plaques in the brain parenchyma. The plaques consist of abnormal deposits mainly composed of an aggregation-prone protein fragment, β-amyloid 1-40/1-42, into the extracellular matrix. Brillouin microspectroscopy is an all-optical contactless technique that is based on the interaction between visible light and longitudinal acoustic waves or phonons, giving access to the viscoelasticity of a sample on a subcellular scale. Here, we describe the first application of micromechanical mapping based on Brillouin scattering spectroscopy to probe the stiffness of individual amyloid plaques in the hippocampal part of the brain of a β-amyloid overexpressing transgenic mouse. Correlative analysis based on Brillouin and Raman microspectroscopy showed that amyloid plaques have a complex structure with a rigid core of β-pleated sheet conformation (β-amyloid protein surrounded by a softer ring-shaped region richer in lipids and other protein conformations. These preliminary results give a new insight into the plaque biophysics and biomechanics, and a valuable contrast mechanism for the study and diagnosis of amyloidopathy.

Electron inelastic scattering by compound nuclei and giant multipole resonances

International Nuclear Information System (INIS)

Dzhavadov, A.V.; Mukhtarov, A.I.; Mirabutalybov, M.M.

1980-01-01

Multipole giant resonances in heavy nuclei have been investigated with the application of the Danos-Greiner dynamic collective theory to the Tassi model. The monopole giant resonance has been studied in 158 Gd, 166 Er, 184 W, 232 Th and 238 V nuclei at the incident electron energy E=200 MeV. Dependences of the form factor square of electron scattering by a 166 Er nucleus on the scattering angle obtained in the distorted-wave high-energy approximation (DWHEA) are presented. Giant dipole and quadrupole resonances in 60 Ni and 90 Zr nuclei have been studied. A comparison has been made of theoretical results obtained in the DWHEA for the dependence of the form factor square on the effective momentum transfer with the experimental data. The analysis of the obtained results led to the following conclusions. To draw a conclusion about the validity of one or another nuclear model and methods for calculating form factors, it is necessary to investigate, both theoretically and experimentally, electron scattering at great angles (THETA>=70 deg). To obtain a good agreement it is necessary to take account of the actual proton and neutron distributions in the ground state and their dynamic properties in an excited state [ru

Raman scattering enhancement in photon-plasmon resonance mediated metal-dielectric microcavity

International Nuclear Information System (INIS)

Guddala, Sriram; Narayana Rao, D.; Dwivedi, Vindesh K.; Vijaya Prakash, G.

2013-01-01

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 −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

Scattering resonances in a low-dimensional Rashba-Dresselhaus spin-orbit coupled quantum gas

Science.gov (United States)

Wang, Su-Ju; Blume, D.

2017-04-01

Confinement-induced resonances allow for the tuning of the effective one-dimensional coupling constant. When the scattering state associated with the ground transverse mode is brought into resonance with the bound state attached to the energetically excited transverse modes, the atoms interact through an infinitely strong repulsion. This provides a route to realize the Tonks-Girardeau gas. On the other hand, the realization of synthetic gauge fields in cold atomic systems has attracted a lot of attention. For instance, bound-state formation is found to be significantly modified in the presence of spin-orbit coupling in three dimensions. This motivates us to study ultracold collisions between two Rashba-Dresselhaus spin-orbit coupled atoms in a quasi-one-dimensional geometry. We develop a multi-channel scattering formalism that accounts for the external transverse confinement and the spin-orbit coupling terms. The interplay between these two single-particle terms is shown to give rise to new scattering resonances. In particular, it is analyzed what happens when the scattering energy crosses the various scattering thresholds that arise from the single-particle confinement and the spin-orbit coupling. Support by the NSF is gratefully acknowledged.

Scattering-Type Surface-Plasmon-Resonance Biosensors

Science.gov (United States)

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

Resonances, scattering theory and rigged Hilbert spaces

International Nuclear Information System (INIS)

Parravicini, G.; Gorini, V.; Sudarshan, E.C.G.

1979-01-01

The problem of decaying states and resonances is examined within the framework of scattering theory in a rigged Hilbert space formalism. The stationary free, in, and out eigenvectors of formal scattering theory, which have a rigorous setting in rigged Hilbert space, are considered to be analytic functions of the energy eigenvalue. The value of these analytic functions at any point of regularity, real or complex, is an eigenvector with eigenvalue equal to the position of the point. The poles of the eigenvector families give origin to other eigenvectors of the Hamiltonian; the singularities of the out eigenvector family are the same as those of the continued S matrix, so that resonances are seen as eigenvectors of the Hamiltonian with eigenvalue equal to their location in the complex energy plane. Cauchy theorem then provides for expansions in terms of complete sets of eigenvectors with complex eigenvalues of the Hamiltonian. Applying such expansions to the survival amplitude of a decaying state, one finds that resonances give discrete contributions with purely exponential time behavior; the background is of course present, but explicitly separated. The resolvent of the Hamiltonian, restricted to the nuclear space appearing in the rigged Hilbert space, can be continued across the absolutely continuous spectrum; the singularities of the continuation are the same as those of the out eigenvectors. The free, in and out eigenvectors with complex eigenvalues and those corresponding to resonances can be approximated by physical vectors in the Hilbert space, as plane waves can. The need for having some further physical information in addition to the specification of the total Hamiltonian is apparent in the proposed framework. The formalism is applied to the Lee-Friedrichs model. 48 references

Application of laser resonance scattering to the study of high-temperature plasma-wall interaction

International Nuclear Information System (INIS)

Maeda, Mitsuo; Muraoka, Katsunori; Hamamoto, Makoto; Akazaki, Masanori; Miyazoe, Yasushi

1981-01-01

Studies on laser resonance scattering and its application to the study of high-temperature plasma-wall interaction are reviewed. The application of dye laser beam to resonant scattering method has been developed. This method is able to detect low density atoms. The fluorescent photon counts can be estimated for a two-level system and a three-level system. The S/N ratio, Which is in close connection with the detection limit, has been estimated. The doppler effect due to the thermal motion of atoms is taken into consideration. The calibration of the absolute number of atoms is necessary. Tunable coherent light is used as the light source for resonance scattering method. This is able to excite atoms strongly and to increase the detection efficiency. As dye lasers, a N 2 laser, a YAG laser, and a KrF excimer laser have been studied. In VUV region, rare gas or rare gas halide lasers can be used. The strong output power can be expected when the resonance lines of atoms meet the synchronizing region of the excimer laser. The resonance scattering method is applied to the detection of impurity metal atoms in plasma. The studies of laser systems for the detection of hydrogen atoms are also in progress. (Kato, T.)

Resonant A1 phonon and four-magnon Raman scattering in hexagonal HoMnO3 thin film

International Nuclear Information System (INIS)

Chen Xiangbai; Thi Minh Hien, Nguyen; Yang, In-Sang; Lee, D; Jang, S-Y; Noh, T W

2010-01-01

We present the results of resonant Raman scattering of the A 1 phonon at 680 cm -1 and of the four-magnon at 760 cm -1 in hexagonal HoMnO 3 thin film. We find that the A 1 phonon at 680 cm -1 shows a strong resonance effect near the on-site Mn d-d transition at ∼1.7 eV. Our Raman results show that the four-magnon scattering can be selectively excited with red lasers of 647 nm (1.92 eV) and 671 nm (1.85 eV), but are not detectable with green lasers of 532 nm (2.33 eV), indicating that the four-magnon scattering in hexagonal HoMnO 3 has an extremely strong resonance effect also near the on-site Mn d-d transition at ∼1.7 eV. Furthermore, through the analyses of our study of the resonant four-magnon Raman scattering and earlier studies of the resonant two-magnon Raman scattering, we propose a simple general model for all resonant magnon scattering. Our simple general model predicts a simple method for the investigation of the spin-flipping/spin-wave in magnetic materials, which would have significant impacts on the applications of spintronic devices.

Coupling effects of resonant and discretized non-resonant continuum states in 4He+6Li scattering at 10 MeV/A

International Nuclear Information System (INIS)

Sinha, T.; Kanungo, R.; Samanta, C.; Ghosh, S.; Basu, P.; Rebel, H.

1996-01-01

Alpha- particle scattering from the resonant (3 + 1 ) and non-resonant continuum states of 6 Li is studied at incident energy 10 MeV/A. The α+d breakup continuum part within the excitation energy E ex = 1.475-2.475 MeV is discretized in two energy bins. Unlike the results at higher incident energies, here the coupled-channel calculations show significant breakup continuum coupling effects on the elastic and inelastic scattering. It is shown that even when the continuum-continuum coupling effects are strong, the experimental data of the ground state and the resonant as well as discretized non-resonant continuum states impose stringent constraint on the coupling strengths of the non-resonant continuum states. (orig.). With 2 figs., 1 tab

Anti-resonance scattering at defect levels in the quantum conductance of a one-dimensional system

Science.gov (United States)

Sun, Z. Z.; Wang, Y. P.; Wang, X. R.

2002-03-01

For the ballistic quantum transport, the conductance of one channel is quantized to a value of 2e^2/h described by the Landauer formula. In the presence of defects, electrons will be scattered by these defects. Thus the conductance will deviate from the values of the quantized conductance. We show that an anti-resonance scattering can occur when an extra defect level is introduced into a conduction band. At the anti-resonance scattering, exact one quantum conductance is destroyed. The conductance takes a non-zero value when the Fermi energy is away from the anti-resonance scattering. The result is consistent with recent numerical calculations given by H. J. Choi et al. (Phys. Rev. Lett. 84, 2917(2000)) and P. L. McEuen et al. (Phys. Rev. Lett. 83, 5098(1999)).

International workshop on resonant X-ray scattering in electrically-ordered systems

Energy Technology Data Exchange (ETDEWEB)

Collins, S.P.; Pettifer, R.F.; Laundy, D.; Ishida, K.; Kokubun, J.; Giles, C.; Yokaichiya, F.; Song, C.; Lee, K.B.; Ji, S.; Koo, J.; Park, Y.J.; Kim, J.Y.; Park, J.H.; Shin, H.J.; Rhyee, J.S.; Oh, B.H.; Cho, B.K.; Wilkins Stuart, B.; Paixao, J.A.; Caciuffo, R.; Javorsky, P.; Wastin, F.; Rebizant, J.; Detlefs, C.; Bernheoft, N.; Lander, G.H.; Bombardi, A.; Bergevin, F. de; Matteo, S. di; Paolasini, L.; Rodriguez-Carvajal, J.; Carretta, P.; Millet, P.; Caciuffo, R.; Goff, J.P.; Deen, P.P.; Lee, S.; Stunault, A.; Brown, S.; Mannix, D.; McIntyre, G.J.; Ward, R.C.C.; Wells, M.R.; Lorenzo, J.E.; Joly, Y.; Nazarenko, E.; Staub, U.; Srajer, G.; Haskel, D.; Choi, Y.; Lee, D.R.; Lang, J.C.; Meersschaut, J.; Jiang, J.S.; Bader, S.D.; Bouchenoire, L.; Brown, S.D.; Beesley, A.; Herring, A.; Thomas, M.; Thompson, P.; Langridge, S.; Stirling, W.G.; Mirone, A.; Lander, G.; Wilkins, S.; Ward, R.C.C.; Wells, M.R.; Zochowski, S.W.; Garcia, J.; Subias, G.; Blasco, J.; Sanchez, M.C.; Proietti, M.G.; Lovesey, S.W.; Dmitrienko, V.E.; Ovchinnikova, E.N.; Ishida, K.; Kokubun, J.; Kirfel, A.; Collins, S.P.; Laundy, D.; Oreshko, A.P.; Strange, P.; Horne, M.; Arola, E.; Winter, H.; Szotek, Z.; Temmerman, W.M.; Igarashi, J.; Usuda, M.; Takahashi, M.; Matteo, S. di; Bernhoeft, N.; Hill, J.P.; Lang, J.C.; McWhan, D.; Lee, D.R.; Haskel, D.; Srajer, G.; Hatton Peter, D.; Katsumata, K.; Braithwaite, D

2004-07-01

The research field of Resonant X-ray Scattering (RXS) has achieved tremendous progress in the last years. Nowadays RXS is rapidly becoming the crucial technique for investigating the subtleties of microscopic magnetism in systems where the ground state properties reflect a delicate balance between several different correlated processes. The aim of this workshop is to discuss present and future possibilities for RXS investigations of electronic order, including studies of charge, magnetic, and multipolar ordered states. The sessions will cover experimental and theoretical aspects of hard and soft X-ray resonant scattering from single crystals and thin films. This document gathers the summaries of the presentations.

International workshop on resonant X-ray scattering in electrically-ordered systems

International Nuclear Information System (INIS)

Collins, S.P.; Pettifer, R.F.; Laundy, D.; Ishida, K.; Kokubun, J.; Giles, C.; Yokaichiya, F.; Song, C.; Lee, K.B.; Ji, S.; Koo, J.; Park, Y.J.; Kim, J.Y.; Park, J.H.; Shin, H.J.; Rhyee, J.S.; Oh, B.H.; Cho, B.K.; Wilkins Stuart, B.; Paixao, J.A.; Caciuffo, R.; Javorsky, P.; Wastin, F.; Rebizant, J.; Detlefs, C.; Bernheoft, N.; Lander, G.H.; Bombardi, A.; Bergevin, F. de; Matteo, S. di; Paolasini, L.; Rodriguez-Carvajal, J.; Carretta, P.; Millet, P.; Caciuffo, R.; Goff, J.P.; Deen, P.P.; Lee, S.; Stunault, A.; Brown, S.; Mannix, D.; McIntyre, G.J.; Ward, R.C.C.; Wells, M.R.; Lorenzo, J.E.; Joly, Y.; Nazarenko, E.; Staub, U.; Srajer, G.; Haskel, D.; Choi, Y.; Lee, D.R.; Lang, J.C.; Meersschaut, J.; Jiang, J.S.; Bader, S.D.; Bouchenoire, L.; Brown, S.D.; Beesley, A.; Herring, A.; Thomas, M.; Thompson, P.; Langridge, S.; Stirling, W.G.; Mirone, A.; Lander, G.; Wilkins, S.; Ward, R.C.C.; Wells, M.R.; Zochowski, S.W.; Garcia, J.; Subias, G.; Blasco, J.; Sanchez, M.C.; Proietti, M.G.; Lovesey, S.W.; Dmitrienko, V.E.; Ovchinnikova, E.N.; Ishida, K.; Kokubun, J.; Kirfel, A.; Collins, S.P.; Laundy, D.; Oreshko, A.P.; Strange, P.; Horne, M.; Arola, E.; Winter, H.; Szotek, Z.; Temmerman, W.M.; Igarashi, J.; Usuda, M.; Takahashi, M.; Matteo, S. di; Bernhoeft, N.; Hill, J.P.; Lang, J.C.; McWhan, D.; Lee, D.R.; Haskel, D.; Srajer, G.; Hatton Peter, D.; Katsumata, K.; Braithwaite, D.

2004-01-01

The research field of Resonant X-ray Scattering (RXS) has achieved tremendous progress in the last years. Nowadays RXS is rapidly becoming the crucial technique for investigating the subtleties of microscopic magnetism in systems where the ground state properties reflect a delicate balance between several different correlated processes. The aim of this workshop is to discuss present and future possibilities for RXS investigations of electronic order, including studies of charge, magnetic, and multipolar ordered states. The sessions will cover experimental and theoretical aspects of hard and soft X-ray resonant scattering from single crystals and thin films. This document gathers the summaries of the presentations

Wavelength modulated surface enhanced (resonance) Raman scattering for background-free detection.

Science.gov (United States)

Praveen, Bavishna B; Steuwe, Christian; Mazilu, Michael; Dholakia, Kishan; Mahajan, Sumeet

2013-05-21

Spectra in surface-enhanced Raman scattering (SERS) are always accompanied by a continuum emission called the 'background' which complicates analysis and is especially problematic for quantification and automation. Here, we implement a wavelength modulation technique to eliminate the background in SERS and its resonant version, surface-enhanced resonance Raman scattering (SERRS). This is demonstrated on various nanostructured substrates used for SER(R)S. An enhancement in the signal to noise ratio for the Raman bands of the probe molecules is also observed. This technique helps to improve the analytical ability of SERS by alleviating the problem due to the accompanying background and thus making observations substrate independent.

Observing shape resonances in ultraslow H^++H elastic scattering

Science.gov (United States)

Macek, J. H.; Schultz, D. R.; Ovchinnikov, S. Yu.; Krstic, P. S.

2004-05-01

We have calculated highly accurate elastic and charge transfer cross sections for proton-hydrogen scattering at energies 0.0001-10 eV, using fully quantal approach (P.S. Krstic and D.R. Schultz, J. Phys. B 32, 3485 (1999)). A number of resonances are observed. We calculate the positions and widths of the shape resonances in the effective potentials for various orbital angular momenta (J. H. Macek and S. Yu. Ovchinnikov, Phys. Rev. A 50, 468 (1994)). These correlate well with the observed resonances. We acknowledge support from the US DOE through ORNL, managed by UT-Battelle, LLC under contract DE-AC05-00OR22725.

Temporal evolution of stimulated Brillouin backscatter

International Nuclear Information System (INIS)

Hinkel, D.E.; Williams, E.A.; Berger, R.L.

1994-01-01

A qualitative understanding of the time dependence of stimulated Brillouin scattering (SBS) provides estimates of the amount of temporal growth that occurs in current inertial confinement fusion and short laser pulse interaction experiments when the growth is limited by the length of the experiment or by motion of the ''hot spots'' of the laser intensity pattern induced by beam smoothing. In the weak coupling limit, the instantaneous growth rate depends upon the plasma initial conditions early in time, is proportional to t -1/2 later in time, and asymptotically approaches the absolute growth rate (in the absence of damping). When the instability is strongly coupled, the growth rate depends upon the plasma initial conditions early in time but is proportional to t -1/3 later in time. When the growth rate drops to a value comparable to that of the ion acoustic frequency, the instability becomes effectively weakly coupled. The effects of damping are also discussed

Angular dependence of resonant inelastic x-ray scattering : A spherical tensor expansion

NARCIS (Netherlands)

Juhin, Amelie; Brouder, Christian; de Groot, Frank

A spherical tensor expansion is carried out to express the resonant inelastic scattering cross-section as a sum of products of fundamental spectra with tensors involving wavevectors and polarization vectors of incident and scattered photons. The expression presented in this paper differs from that

Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory.

Science.gov (United States)

Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D

2016-01-14

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 X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 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.

Observations of resonance-like structures for positron-atom elastic scattering at intermediate energies

International Nuclear Information System (INIS)

Dou, L.; Kauppila, W.E.; Kwan, C.K.; Stein, T.S.

1993-01-01

We have measured absolute values of elastic differential cross sections (DCS's) for positron (e + ) scattering by argon (8.7-300 eV), krypton (6.7-400 eV), and also neon (13.6-400 eV) using a crossed-beam experimental setup. When the DCS's are plotted at fixed scattering angles of 30 degrees, 60 degrees, 90 degrees, and 120 degrees versus energy it has been found that well-defined resonance-like structures were found at an energy of 55-60 eV for argon and at 25 and 200 eV for krypton, with a broader structure found between 100-200 eV for neon. These observed resonance-like structures are unusual because they occur at energies well above the known inelastic thresholds for these atoms. They may represent examples of open-quotes coupled channel shape resonancesclose quotes, first predicted by Higgins and Burke for e + -H scattering in the vicinity of 36 eV (width ∼ 4 eV), which occurs only when both the elastic and positronium formation scattering channels are considered together. A more recent e + -H calculation by Hewitt et al. supports the Higgins and Burke prediction. These predictions and the present observations suggest the existence of a new type of atomic scattering resonance

Double peak-induced distance error in short-time-Fourier-transform-Brillouin optical time domain reflectometers event detection and the recovery method.

Science.gov (United States)

Yu, Yifei; Luo, Linqing; Li, Bo; Guo, Linfeng; Yan, Jize; Soga, Kenichi

2015-10-01

The measured distance error caused by double peaks in the BOTDRs (Brillouin optical time domain reflectometers) system is a kind of Brillouin scattering spectrum (BSS) deformation, discussed and simulated for the first time in the paper, to the best of the authors' knowledge. Double peak, as a kind of Brillouin spectrum deformation, is important in the enhancement of spatial resolution, measurement accuracy, and crack detection. Due to the variances of the peak powers of the BSS along the fiber, the measured starting point of a step-shape frequency transition region is shifted and results in distance errors. Zero-padded short-time-Fourier-transform (STFT) can restore the transition-induced double peaks in the asymmetric and deformed BSS, thus offering more accurate and quicker measurements than the conventional Lorentz-fitting method. The recovering method based on the double-peak detection and corresponding BSS deformation can be applied to calculate the real starting point, which can improve the distance accuracy of the STFT-based BOTDR system.

Resonance effects in Raman scattering of quantum dots formed by the Langmuir-Blodgett method

Energy Technology Data Exchange (ETDEWEB)

Milekhin, A G; Sveshnikova, L L; Duda, T A [Institute of Semiconductor Physics, Lavrentjev av.13, 630090, Novosibirsk (Russian Federation); Surovtsev, N V; Adichtchev, S V [Institute of Automation and Electrometry, Koptyug av.1, 630090, Novosibirsk (Russian Federation); Azhniuk, Yu M [Institute of Electron Physics, Universytetska Str. 21, 88017, Uzhhorod (Ukraine); Himcinschi, C [Institut fuer Theoretische Physik, TU Bergakademie Freiberg, Leipziger Str. 23, 09596, Freiberg (Germany); Kehr, M; Zahn, D R T, E-mail: milekhin@thermo.isp.nsc.r [Semiconductor Physics, Chemnitz University of Technology, Chemnitz (Germany)

2010-09-01

The enhancement of Raman scattering by optical phonon modes in quantum dots was achieved in resonant and surface-enhanced Raman scattering experiments by approaching the laser energy to the energy of either the interband transitions or the localized surface plasmons in silver nanoclusters deposited onto the nanostructures. Resonant Raman scattering by TO, LO, and SO phonons as well as their overtones was observed for PbS, ZnS, and ZnO quantum dots while enhancement for LO and SO modes in CdS quantum dots with a factor of about 700 was measured in surface enhanced Raman scattering experiments. Multiple phonon Raman scattering observed up to 5th and 7th order for CdS and ZnO, respectively, confirms the high crystalline quality of the grown QDs.

Interaction-driven sub-gap resonance in the topological Kondo insulator SmB6

Science.gov (United States)

Fuhrman, Wesley

2015-03-01

Samarium hexaboride (SmB6) is a strongly correlated Kondo Insulator with a non-trivial band-structure topology. I will discuss recent neutron scattering experiments and analysis that expose a 14 meV resonant mode in SmB6 and relate it to the low energy insulating band structure. Repeating outside the first Brillouin zone, the mode is coherent with a 5 d-like magnetic form factor. I will discuss how band inversion can be inferred from neutron scattering and show that a perturbative slave boson treatment of a hybridized 2 species (d/ f) band structure within an Anderson model can produce a spin exciton with the observed characteristics. This analysis provides a detailed physical picture of how the SmB6 band topology arises from strong electron interactions, and accounts for the 14 meV resonant mode as a magnetically active exciton. The work at IQM was supported by the US Department of Energy, office of Basic Energy Sciences, Division of Material Sciences and Engineering under Grant DE-FG02-08ER46544.

Impact of the Improved Resonance Scattering Kernel on HTR Calculations

International Nuclear Information System (INIS)

Becker, B.; Dagan, R.; Broeders, C.H.M.; Lohnert, G.

2008-01-01

The importance of an advanced neutron scattering model for heavy isotopes with strong energy dependent cross sections such as the pronounced resonances of U 238 has been discussed in various publications where the full double differential scattering kernel was derived. In this study we quantify the effect of the new scattering model for specific innovative types of High Temperature Reactor (HTR) systems which commonly exhibit a higher degree of heterogeneity and higher fuel temperatures, hence increasing the importance of the secondary neutron energy distribution. In particular the impact on the multiplication factor (k ∞ ) and the Doppler reactivity coefficient is presented in view of the packing factors and operating temperatures. A considerable reduction of k ∞ (up to 600 pcm) and an increased Doppler reactivity (up to 10%) is observed. An increase of up to 2.3% of the Pu 239 inventory can be noticed at 90 MWd/tHM burnup due to enhanced neutron absorption of U 238 . Those effects are more pronounced for design cases in which the neutron flux spectrum is hardened towards the resolved resonance range. (authors)

Resonant inelastic x-ray scattering studies of elementary excitations

NARCIS (Netherlands)

Ament, Lucas Johannes Peter (Luuk)

2010-01-01

Resonant Inelastic X-ray Scattering (RIXS) is an X-ray in, X-ray out technique that enables one to study the dispersion of excitations in solids. In this thesis, we investigated how various elementary excitations of transition metal oxides show up in RIXS spectra.

Fingerprints of orbital physics in magnetic resonant inelastic X-ray scattering

Science.gov (United States)

Marra, Pasquale

2012-09-01

Orbital degrees of freedom play a major role in the physics of many strongly correlated transition metal compounds. However, they are still very difficult to access experimentally, in particular by neutron scattering. We propose here how to reveal orbital occupancies of the system ground state by magnetic resonant inelastic x-ray scattering (RIXS). This is possible because, unlike in neutron scattering, the intensity of the magnetic excitations in RIXS depends essentially on the symmetry of the orbitals where the spins are in.

Resonant intersubband polariton-LO phonon scattering in an optically pumped polaritonic device

Science.gov (United States)

Manceau, J.-M.; Tran, N.-L.; Biasiol, G.; Laurent, T.; Sagnes, I.; Beaudoin, G.; De Liberato, S.; Carusotto, I.; Colombelli, R.

2018-05-01

We report experimental evidence of longitudinal optical (LO) phonon-intersubband polariton scattering processes under resonant injection of light. The scattering process is resonant with both the initial (upper polariton) and final (lower polariton) states and is induced by the interaction of confined electrons with longitudinal optical phonons. The system is optically pumped with a mid-IR laser tuned between 1094 cm-1 and 1134 cm-1 (λ = 9.14 μm and λ = 8.82 μm). The demonstration is provided for both GaAs/AlGaAs and InGaAs/AlInAs doped quantum well systems whose intersubband plasmon lies at a wavelength of ≈10 μm. In addition to elucidating the microscopic mechanism of the polariton-phonon scattering, it is found to differ substantially from the standard single particle electron-LO phonon scattering mechanism, and this work constitutes an important step towards the hopefully forthcoming demonstration of an intersubband polariton laser.

Scattering amplitude of ultracold atoms near the p-wave magnetic Feshbach resonance

International Nuclear Information System (INIS)

Zhang Peng; Naidon, Pascal; Ueda, Masahito

2010-01-01

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 1 (k) is given by f 1 (k)=-1/[ik+1/(Vk 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 1 (k)=-1/[ik+1/(V eff k 2 )+1/(S eff k)+1/R eff ] where V eff , S eff , and R 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 6 Li and 40 K when the scattering volume is enhanced by the resonance.

Inelastic resonant M-scattering of X-rays from Gd metal with inner-shell excitation

International Nuclear Information System (INIS)

Braicovich, L.; Tagliaferri, A.

1998-01-01

The paper presents results on resonant inner-shell scattering in Gd across the M 5 threshold; the scattering channel with formally a 4 p hole in the final state is studied. Two scattering channels are in competition: one at constant transferred energy and another at constant outgoing energy. The branching ratio of the process at constant transferred energy is about 5%. It's isolated the many-body satellite structure of the formally 4p 3/2 final hole state and it's discussed the importance of the multiplet splitting and of the super Coster-Kronig conversion of this state into another final state with two 4 d holes. The results with resonant M 5 excitation are also compared with those of non-resonant excitation well above the M 4 threshold. Guidelines for future research are briefly presented

RESONANT X-RAY SCATTERING AS A PROBE OF ORBITAL AND CHARGE ORDERING

International Nuclear Information System (INIS)

NELSON, C.S.; HILL, J.P.; GIBBS, D.

2002-01-01

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 3+ and Mn 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. Two

Numerical investigation of the influence of the strictive self-interaction on the quality of phase conjugation in the course of stimulated Brillouin scattering

International Nuclear Information System (INIS)

Kir'yanov, Yu F; Kochemasov, G G; Maslov, N V; Shestakova, I V

1999-01-01

The influence of the strictive self-interaction on the threshold and quality of phase conjugation in the course of stimulated Brillouin scattering (SBS) was investigated numerically in the linear approximation for steady-state linearly polarised pumping. The calculations were carried out for the three-dimensional case of a Gaussian pump beam and a beam representing a superposition of 10 x 10 Hermitian - Gaussian modes with random phases. It was found that in the case of a Gaussian beam the growth of the strictive aberrations leads to a significant reduction of the SBS threshold but has little influence on the conjugation quality. In the case of a pump beam with a divergence exceeding the diffraction limit such growth of the strictive aberrations results (on the average) in lowering the SBS threshold and in deterioration of the conjugation quality. The calculated results depend strongly on the specific phase combination of the superposed modes. (nonlinear optical phenomena)

Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

International Nuclear Information System (INIS)

Alexeev, P.

2017-04-01

This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in "1"9"3Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO_2 and in Ruddlesden-Popper (RP) phases of strontium iridates Sr_n_+_1Ir_nO_3_n_+_1 (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO_2, SrIrO_3 and Sr_2IrO_4 have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field on Ir nucleus have been determined for

Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

Energy Technology Data Exchange (ETDEWEB)

Alexeev, P.

2017-04-15

This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in {sup 193}Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO{sub 2} and in Ruddlesden-Popper (RP) phases of strontium iridates Sr{sub n+1}Ir{sub n}O{sub 3n+1} (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO{sub 2}, SrIrO{sub 3} and Sr{sub 2}IrO{sub 4} have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field

Preliminary results on application of the multiple-scattering technique to electron--molecule scattering and molecular photoionization: the PI/sub g/ resonance in e-N2 scattering

International Nuclear Information System (INIS)

Dehmer, J.L.; Dill, D.

1974-01-01

A prototype calculation of the well-known 2.5-eV shape resonance in e-N 2 scattering was performed to test the usefulness of the multiple-scattering method for electronic continuum molecular wavefunctions. The results of this demanding test are very encouraging. (U.S.)

ππ P-wave resonant scattering from lattice QCD

Directory of Open Access Journals (Sweden)

Paul Srijit

2018-01-01

Full Text Available We present a high-statistics analysis of the ρ resonance in ππ scattering, using 2 + 1 flavors of clover fermions at a pion mass of approximately 320 MeV and a lattice size of approximately 3:6 fm. The computation of the two-point functions are carried out using combinations of forward, sequential, and stochastic propagators. For the extraction of the ρ-resonance parameters, we compare different fit methods and demonstrate their consistency. For the ππ scattering phase shift, we consider different Breit-Wigner parametrizations and also investigate possible nonresonant contributions. We find that the minimal Breit-Wigner model is suffcient to describe our data, and obtain amρ = 0:4609(16stat(14sys and gρππ = 5:69(13stat(16sys. In our comparison with other lattice QCD results, we consider the dimensionless ratios amρ/amN and amπ/amN to avoid scale setting ambiguities.

ππ P-wave resonant scattering from lattice QCD

Science.gov (United States)

Paul, Srijit; Alexandrou, Constantia; Leskovec, Luka; Meinel, Stefan; Negele, John W.; Petschlies, Marcus; Pochinsky, Andrew; Rendon Suzuki, Jesus Gumaro; Syritsyn, Sergey

2018-03-01

We present a high-statistics analysis of the ρ resonance in ππ scattering, using 2 + 1 flavors of clover fermions at a pion mass of approximately 320 MeV and a lattice size of approximately 3:6 fm. The computation of the two-point functions are carried out using combinations of forward, sequential, and stochastic propagators. For the extraction of the ρ-resonance parameters, we compare different fit methods and demonstrate their consistency. For the ππ scattering phase shift, we consider different Breit-Wigner parametrizations and also investigate possible nonresonant contributions. We find that the minimal Breit-Wigner model is suffcient to describe our data, and obtain amρ = 0:4609(16)stat(14)sys and gρππ = 5:69(13)stat(16)sys. In our comparison with other lattice QCD results, we consider the dimensionless ratios amρ/amN and amπ/amN to avoid scale setting ambiguities.

Resonances above the ionization threshold in positron-hydrogen scattering

International Nuclear Information System (INIS)

Kernoghan, A.A.; Walters, H.R.J.; McAlinden, M.T.

1994-01-01

Resonances appearing above the ionization threshold in coupled-state calculations of positron-atom scattering are discussed. Calculations in the six state approximation Ps(1s, 2s, 2p) + H(1s, 2s, 2p), which show such resonance structure, are compared with a more extensive 18-state approximation Ps(1s, 2s, 3s, 4s, 2p, 3p, 4p, 3d, 4d) + H(1s, 2s, 3s, 4s, 2p, 3p, 4p, 3d, 4d) in which channels other than 1s, 2s and 2p are represented by pseudostates. The results strongly indicate that the above ionization threshold resonances observed in the six-state approximation, and in other small basis set calculations, are not real. It is suggested that they are a consequence of the neglect, or inadequate representation in other approximations, of ionization channels. In the six-state approximation the positronium component of the system wavefunction attempts to represent the missing ionization channels but in so doing produces unreal resonances above the ionization threshold. More generally it is suggested that, in coupled-state calculations of positron-atom scattering, the atom part of the system wavefunction will try to compensate for defects in the positronium component and vice versa. When the defects are serious, for example, the omission of important ionization channels, unusual spurious behaviour is to be expected. (Author)

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

Science.gov (United States)

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

2011-01-01

The interaction between palladium(II)-aminophylline and fluorescein sodium was investigated by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum. In pH 4.4 Britton-Robinson (BR) buffer medium, aminophylline (Ami) reacted with palladium(II) to form chelate cation([Pd(Ami)]2+), which further reacted with fluorescein sodium (FS) to form ternary mixed ligand complex [Pd(Ami)(FS)2]. As a result, resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering spectrum (FDS) were enhanced. The maximum scattering wavelengths of [Pd(Ami)(FS)2] were located at 300 nm (RRS), 650 nm (SOS) and 304 nm (FDS). The scattering intensities were proportional to the Ami concentration in a certain range and the detection limits were 7.3 ng mL(-1) (RRS), 32.9 ng mL(-1) (SOS) and 79.1 ng mL(-1) (FDS), respectively. Based on it, the new simple, rapid, and sensitive scattering methods have been proposed to determine Ami in urine and serum samples. Moreover, the formation mechanism of [Pd(Ami)(FS)2] and the reasons for enhancement of RRS were fully discussed. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

Sikdar, Debabrata, E-mail: debabrata.sikdar@monash.edu; Premaratne, Malin [Advanced Computing and Simulation Laboratory (A chi L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton 3800, Victoria (Australia); Cheng, Wenlong [Department of Chemical Engineering, Faculty of Engineering, Monash University, Clayton 3800, Victoria (Australia); The Melbourne Centre for Nanofabrication, 151 Wellington Road, Clayton 3168, Victoria (Australia)

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

Elastic anisotropy of polycrystalline Au films: Modeling and respective contributions of X-ray diffraction, nanoindentation and Brillouin light scattering

International Nuclear Information System (INIS)

Faurie, D.; Djemia, P.; Le Bourhis, E.; Renault, P.-O.; Roussigne, Y.; Cherif, S.M.; Brenner, R.; Castelnau, O.; Patriarche, G.; Goudeau, Ph.

2010-01-01

Elastic properties of non-textured and {1 1 1}-fiber-textured gold thin films were investigated experimentally by several complementary techniques, namely in situ tensile testing under X-ray diffraction (XRD), nanoindentation and Brillouin light scattering (BLS). Specimens were probed along different directions to reveal the strong effects of elastic anisotropy at the (local) grain and (global) film scales. XRD allows the investigation of both local and global anisotropies, while BLS and nanoindentation are limited to global analyses. A micromechanical model, based on the self-consistent scheme, and accounting for the actual microstructure of the films, is applied to interpret experimental data. Although different types of elastic constants can be determined with the used experimental techniques (static/dynamic, local/global), a good agreement is obtained, showing that comparison of these techniques is feasible when carried out carefully. In particular, the use of a micromechanical model to estimate the effects of the local elastic anisotropy at the film scale is unavoidable. The presented results show that XRD, BLS and nanoindentation should capture anisotropic texture effects on elastic constants measurements for materials with a Zener anisotropy index larger than 2. Conversely, the actual texture of a given specimen should be taken into account for a proper analysis of elastic constants measurements using those three experimental techniques.

Development of in situ Brillouin spectroscopy at high pressure and high temperature with synchrotron radiation and infrared laser heating system: Application to the Earth's deep interior

Science.gov (United States)

Murakami, Motohiko; Asahara, Yuki; Ohishi, Yasuo; Hirao, Naohisa; Hirose, Kei

2009-05-01

Seismic wave velocity profiles in the Earth provide one of the strongest constraints on structure, mineralogy and elastic properties of the Earth's deep interior. Accurate sound velocity data of deep Earth materials under relevant high-pressure and high-temperature conditions, therefore, are essential for interpretation of seismic data. Such information can be directly obtained from Brillouin scattering measurement. Here we describe an in situ Brillouin scattering system for measurements at high pressure and high temperature using a laser heated diamond anvil cell and synchrotron radiation for sample characterization. The system has been used with single-crystal and polycrystalline materials, and with glass and fluid phase. It provided high quality sound velocity and elastic data with X-ray diffraction data at high pressure and/or high temperature. Those combined techniques can potentially offer the essential information for resolving many remaining issues in mineral physics.

A Stochastic Proof of the Resonant Scattering Kernel and its Applications for Gen IV Reactors Type

International Nuclear Information System (INIS)

Becker, B.; Dagan, R.; Broeders, C.H.M.; Lohnert, G.

2008-01-01

Monte Carlo codes such as MCNP are widely accepted as almost-reference for reactor analysis. The Monte Carlo Code should therefore use as few as possible approximations in order to produce 'experimental-level' calculations. In this study we deal with one of the most problematic approximations done in MCNP in which the resonances are ignored for the secondary neutron energy distribution, namely the change of the energy and angular direction of the neutron after interaction with a heavy isotope with pronounced resonances. The endeavour of exploiting the influence of the resonances on the scattering kernel goes back to 1944 where E. Wigner and J. Wilkins developed the first temperature dependent scattering kernel. However only in 1998, the full analytical solution for the double differential resonant dependent scattering kernel was suggested by W. Rothenstein and R. Dagan. An independent stochastic approach is presented for the first time to confirm the above analytical kernel with a complete different methodology. Moreover, by manipulating in a subtle manner the scattering subroutine COLIDN of MCNP, it is proven that this very subroutine is, to some extent, inappropriate as well as the relevant explanation in the MCNP manual. The impact of this improved resonance dependent scattering kernel on diverse types of reactors, in particular for the Generation IV innovative core design HTR, is shown to be significant. (authors)

Acoustic profilometry within polymers as performed by Brillouin microscopy

Energy Technology Data Exchange (ETDEWEB)

Sanctuary, R [Laboratoire Europeen de Recherche Universitaire Saarland-Lorraine (LERUSL) at the Centre Universitaire de Luxembourg, Departement des Sciences, Laboratoire 1.19, 162a avenue de la Faiencerie, L-1511 Luxembourg (Luxembourg); Bactavatchalou, Ravi [Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Mueller, Ulrich [Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany); Possart, W [Universitaet des Saarlandes, Fakultaet fuer Chemie, Pharmazie und Werkstoffwissenschaften 8.15, Gebaeude 22, D-66041 Saarbruecken (Germany); Alnot, P [Laboratoire de Physique des Milieux Ionises et Applications (LPMIA), UMR 7040-C.N.R.S, Universite de Nancy I, Bd des Aiguillettes, B.P. 239 F-54506 Vandoeuvre les Nancy (France); Krueger, J K [Universitaet des Saarlandes, Fakultaet fuer Physik und Elektrotechnik 7.2, Gebaeude 38, D-66041 Saarbruecken (Germany)

2003-11-07

Using high performance Brillouin spectroscopy we present a new technique, which enables us to perform acoustic microscopy with a spatial resolution of about 1 {mu}m. This technique, called Brillouin microscopy, is tested on several bulk- and film-like polymer samples.

Wave packet formulation of the boomerang model for resonant electron--molecule scattering

International Nuclear Information System (INIS)

McCurdy, C.W.; Turner, J.L.

1983-01-01

A time-dependent formulation of the boomerang model for resonant electron--molecule scattering is presented in terms of a wave packet propagating on the complex potential surface of the metastable anion. The results of calculations using efficient semiclassical techniques for propagating the wave packet are found to be in excellent agreement with full quantum-mechanical calculations of vibrational excitation cross sections in e - --N 2 scattering. The application of the wave packet formulation as a computational and conceptual approach to the problem of resonant collisions with polyatomic molecules is discussed in the light of recent wave packet calculations on polyatomic photodissociation and Raman spectra

Λ(1405) resonance in baryon-meson scattering with a bound state embedded in the continuum

International Nuclear Information System (INIS)

Takeuchi, Sachiko; Shimizu, Kiyotaka

2009-01-01

We investigate Λ(1405) as a resonance in a coupled-channels baryon-meson (Σπ-NK-Λη) scattering with a 'bound state embedded in the continuum' (BSEC). For this purpose, we solve the Lippmann-Schwinger equation including a BSEC with the semirelativistic kinematics in the momentum space. This BSEC is introduced by hand, as a state not originated from a simple baryon-meson system. We assume it comes from the three-quark state. There appears a resonance in the Σπ scattering below the NK threshold without introducing a BSEC when the NK channel has a strong attraction, just like the chiral unitary approach. Even if the baryon-meson interaction is weakened by using a lower-momentum cut-off parameter, a resonance also appears around 1405 MeV when a BSEC is introduced. The corresponding peak also has a large width, and the NK scattering length is well reproduced. The interaction whose channel dependence is the same as the one originated from the color-magnetic interaction, where no NK attraction exists, also gives a broad peak with help of a BSEC. In order to reproduce the observed NK scattering length, the calculation including a BSEC seems to be preferable. Our calculation gives an appropriate NK scattering length when the BSEC contribution to the resonance is roughly half that of the NK channel.

RESONANT MAGNETIC-X-RAY SCATTERING FROM MIXED-VALENCE TMSE

NARCIS (Netherlands)

MCWHAN, DB; ISAACS, ED; CARRA, P; SHAPIRO, SM; THOLE, BT; HOSHINO, S

1993-01-01

The mixed-valent compound TmSe has been studied in its antiferromagnetic state (T resonant magnetic x-ray scattering. The (003) magnetic reflection shows two peaks as a function of incident energy corresponding to the L(III) absorption edges of its Tm2+ and Tm2+ configurations. This

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

Energy Technology Data Exchange (ETDEWEB)

Nazarov, S A [St. Petersburg State Politechnical University, St. Petersburg (Russian Federation)

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.

On stimulated scattering of laser light in inertial fusion energy targets

International Nuclear Information System (INIS)

Nikolic, Lj; Skoric, M.M.; Ishiguro, S.; Sato, T.

2002-11-01

Propagation of a laser light through regions of an underdense plasma is an active research topic in laser fusion. In particular, a large effort has been invested in studies of stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) which can reflect laser energy and produce energetic particles to preheat a fusion energy target. Experiments, theory and simulations agree on a complex interplay between various laser-plasma instabilities. By particle-in-cell simulations of an underdense electron-plasma, we have found, apart from the standard SRS, a strong backscattering near the electron plasma frequency at densities beyond the quarter critical. This novel instability, recognized in recent experiments as stimulated laser scattering on a trapped electron-acoustic mode (SEAS), is absent from a classical theory of laser-parametric instabilities. A parametric excitation of SEAS instability, is explained by a three-wave resonant decay of the incident laser light into a standing backscattered wave and a slow trapped electron acoustic wave (ω p ). Large SEAS pulsations, eventually suppressed by relativistic heating of electrons, are observed in our simulations. This phenomenon seems relevant to future hohlraum target and fast ignition experiments. (author)

Generalized theory of resonance scattering (GTRS) using the translational addition theorem for spherical wave functions.

Science.gov (United States)

Mitri, Farid

2014-11-01

The generalized theory of resonance scattering (GTRS) by an elastic spherical target in acoustics is extended to describe the arbitrary scattering of a finite beam using the addition theorem for the spherical wave functions of the first kind under a translation of the coordinate origin. The advantage of the proposed method over the standard discrete spherical harmonics transform previously used in the GTRS formalism is the computation of the off-axial beam-shape coefficients (BSCs) stemming from a closed-form partial-wave series expansion representing the axial BSCs in spherical coordinates. With this general method, the arbitrary acoustical scattering can be evaluated for any particle shape and size, whether the particle is partially or completely illuminated by the incident beam. Numerical examples for the axial and off-axial resonance scattering from an elastic sphere placed arbitrarily in the field of a finite circular piston transducer with uniform vibration are provided. Moreover, the 3-D resonance directivity patterns illustrate the theory and reveal some properties of the scattering. Numerous applications involving the scattering phenomenon in imaging, particle manipulation, and the characterization of multiphase flows can benefit from the present analysis because all physically realizable beams radiate acoustical waves from finite transducers as opposed to waves of infinite extent.

Atom-atom scattering under cylindrical harmonic confinement: Numerical and analytic studies of the confinement induced resonance

International Nuclear Information System (INIS)

Bergeman, T.; Moore, M.G.; Olshanii, M.

2003-01-01

It was recently predicted [Phys. Rev. Lett. 81, 938 (1998)10.1103/PhysRevLett.81.938] that atom-atom scattering under transverse harmonic confinement is subject to a 'confinement-induced resonance' where the effective one-dimensional coupling strength diverges at a particular ratio of the confinement and scattering lengths. As the initial prediction made use of the zero-range pseudopotential approximation, we now report numerical results for finite-range interaction potentials that corroborate this resonance. In addition, we now present a physical interpretation of this effect as a novel type of Feshbach resonance in which the transverse modes of the confining potential assume the roles of 'open' and 'closed' scattering channels

Nonlinear propagation of a spatially incoherent laser beam: self-induced smoothing and reduction of scattering instabilities

International Nuclear Information System (INIS)

Maximov, A.V.; Ourdev, I.G.; Rozmus, W.; Capjack, C.E.; Mounaix, Ph.; Huller, S.; Pesme, D.; Tikhonchuk, V.T.; Divol, L.

2000-01-01

It is shown that plasma-induced angular spreading and spectral broadening of a spatially incoherent laser beam correspond to increased spatial and temporal incoherence of the laser light. The spatial incoherence is characterized by an effective beam f-number, decreasing in space along the direction of light propagation. Plasma-induced beam smoothing can influence laser-plasma interaction physics. In particular, decreasing the correlation time of the propagating laser light may dramatically reduce the levels of backward stimulated Brillouin and Raman scattering inside the plasma. Also, the decrease of the laser beam effective f-number reduces the reflectivity of backward stimulated Brillouin scattering. (authors)

Resonance families and local duality relations in the meson-baryon scattering

International Nuclear Information System (INIS)

Ino, Taketoshi

1989-01-01

The local duality relations proposed previously are applied systematically to the P 8 -B 8 scattering, where P 8 and B 8 denote the 0 - unitary octet and 1/2 + one, respectively. The system of the relations involves the harmonic-oscillator spectrum of SU(6) x O(3) L multiplets, and for a process with one exotic channel (the exotic u-channel), the relation relates the s-channel resonance family N s with the t-channel one N t in terms of residues of the scattering amplitude at s-and t-channel resonances a and b (a is an element of N s , b is an element of N t ) in the narrow-width approximation. The resonance family N s (N t ) is defined to be a set of s-(t-) channel resonances with a fixed total number N s (N t ) of quanta of harmonic-oscillator excitations. The system of the relations is powerful in predicting mass ratios and coupling ratios for resonances. It is found that predictions are consistent with available experiments. Some discussion is made on the present results and previous successes in a work where we obtained a uniquely determined π - π + →π - π + dual Born amplitude, starting with the most general Veneziano-type amplitude and restricting parameters in it by the system of the relations and an asymptotic convergence condition. (author)

Resonant elastic scattering, inelastic scattering and astrophysical reactions; Diffusion elastique resonante, diffusion inelastique et reactions astrophysiques

Energy Technology Data Exchange (ETDEWEB)

De Oliveira Santos, F. [Grand Accelerateur National d' Ions Lourds, UMR 6415, 14 - Caen (France)

2007-07-01

Nuclear reactions can occur at low kinetic energy. Low-energy reactions are characterized by a strong dependence on the structure of the compound nucleus. It turns out that it is possible to study the nuclear structure by measuring these reactions. In this course, three types of reactions are treated: Resonant Elastic Scattering (such as N{sup 14}(p,p)N{sup 14}), Inelastic Scattering (such as N{sup 14}(p,p')N{sup 14*}) and Astrophysical reactions (such as N{sup 14}(p,{gamma})O{sup 15}). (author)

Resonant Rayleigh scattering of exciton-polaritons in multiple quantum wells

DEFF Research Database (Denmark)

Malpuech, Guillaume; Kavokin, Alexey; Langbein, Wolfgang Werner

2000-01-01

A theoretical concept of resonant Rayleigh scattering (RRS) of exciton-polaritons in multiple quantum wells (QWs) is presented. The optical coupling between excitons in different QWs can strongly affect the RRS dynamics, giving rise to characteristic temporal oscillations on a picosecond scale....... Bragg and anti-Bragg arranged QW structures with the same excitonic parameters are predicted to have drastically different RRS spectra. Experimental data on the RRS from multiple QWs show the predicted strong temporal oscillations at small scattering angles, which are well explained by the presented...

Resonant Inverse Compton Scattering Spectra from Highly Magnetized Neutron Stars

Science.gov (United States)

Wadiasingh, Zorawar; Baring, Matthew G.; Gonthier, Peter L.; Harding, Alice K.

2018-02-01

Hard, nonthermal, persistent pulsed X-ray emission extending between 10 and ∼150 keV has been observed in nearly 10 magnetars. For inner-magnetospheric models of such emission, resonant inverse Compton scattering of soft thermal photons by ultrarelativistic charges is the most efficient production mechanism. We present angle-dependent upscattering spectra and pulsed intensity maps for uncooled, relativistic electrons injected in inner regions of magnetar magnetospheres, calculated using collisional integrals over field loops. Our computations employ a new formulation of the QED Compton scattering cross section in strong magnetic fields that is physically correct for treating important spin-dependent effects in the cyclotron resonance, thereby producing correct photon spectra. The spectral cutoff energies are sensitive to the choices of observer viewing geometry, electron Lorentz factor, and scattering kinematics. We find that electrons with energies ≲15 MeV will emit most of their radiation below 250 keV, consistent with inferred turnovers for magnetar hard X-ray tails. More energetic electrons still emit mostly below 1 MeV, except for viewing perspectives sampling field-line tangents. Pulse profiles may be singly or doubly peaked dependent on viewing geometry, emission locale, and observed energy band. Magnetic pair production and photon splitting will attenuate spectra to hard X-ray energies, suppressing signals in the Fermi-LAT band. The resonant Compton spectra are strongly polarized, suggesting that hard X-ray polarimetry instruments such as X-Calibur, or a future Compton telescope, can prove central to constraining model geometry and physics.

Theoretical studies of some nonlinear laser-plasma interactions

International Nuclear Information System (INIS)

Cohen, B.I.

1975-01-01

The nonlinear coupling of intense, monochromatic, electromagnetic radiation with plasma is considered in a number of special cases. The first part of the thesis serves as an introduction to three-wave interactions. A general formulation of the stimulated scattering of transverse waves by longitudinal modes in a warm, unmagnetized, uniform plasma is constructed. A general dispersion relation is derived that describes Raman and Brillouin scattering, modulational instability, and induced Thomson scattering. Raman scattering (the scattering of a photon into another photon and an electron plasma wave) is investigated as a possible plasma heating scheme. Analytic theory complemented by computer simulation is presented describing the nonlinear mode coupling of laser light with small and large amplitude, resonantly excited electron plasma waves. The simulated scattering of a coherent electromagnetic wave by low frequency density perturbations in homogeneous plasma is discussed. A composite picture of the linear dispersion relations for filamentation and Brillouin scattering is constructed. The absolute instability of Brillouin weak and strong coupling by analytic and numerical means is described

Resonances and analyticity of scattering wave function for square-well-type potentials

International Nuclear Information System (INIS)

Weber, T.A.; Hammer, C.L.; Zidell, V.S.

1982-01-01

In this paper we extend our previous analysis of the scattering of wave packets in one dimension to the case of the square-well potential. The analytic properties of the general scattering solution are emphasized thereby making the analysis useful as introductory material for a more sophisticated S-matrix treatment. The square-well model is particularly interesting because of its application to the deuteron problem. Resonance scattering, barrier penetration, time delay, and line shape are discussed at the level of the first-year graduate student

One phonon resonant Raman scattering in free-standing quantum wires

International Nuclear Information System (INIS)

Zhao, Xiang-Fu; Liu, Cui-Hong

2007-01-01

The scattering intensity (SI) of a free-standing cylindrical semiconductor quantum wire for an electron resonant Raman scattering (ERRS) process associated with bulk longitudinal optical (LO) phonon modes and surface optical (SO) phonon modes is calculated separately for T=0 K. The Frohlich interaction is considered to illustrate the theory for GaAs and CdS systems. Electron states are confined within a free-standing quantum wire (FSW). Single parabolic conduction and valence bands are assumed. The selection rules are studied. Numerical results and a discussion are also presented for various radii of the cylindrical

Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering

International Nuclear Information System (INIS)

Barbara Pasquini; Marc Vanderhaeghen

2004-01-01

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 γ* N → π 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

Research and development of distributed optic fiber sensors based on Brillouin scattering%布里渊散射的分布式光纤温度传感器的研究进展

Institute of Scientific and Technical Information of China (English)

胡佳惠; 张大伟; 陶春先; 黄元申; 倪争技; 庄松林

2011-01-01

提要：基于布里渊散射的分布式光纤温度传感技术凭借着其独特的优点，在国内外引起了广泛的关注，成为了一大热点研究，本文综述了基于布里渊散射的分布式光纤温度传感技术的研究现状。在简单介绍了布里渊测温原理的基础上，针对目前布里渊散射的光纤温度传感器存在的在测量范围以及空间分辨率上的缺陷、不足，重点介绍了布里渊散射的分布式光纤温度传感器在一些方法上对测量范围以及空间分辨率上的改进。并对日后布里渊的分布式光纤温度传感器的发展趋势做了展望。%The distributed optic fiber sensors based on Brillouin scattering attracts widely attention because of its unique strengths.The improvement of distributed optic fiber sensors based on Brillouin scattering was reviewed in several field such as spatial resolution,measuring range.After introducing the measurement principles of this technique,some research of the recent situation and finally some predictions of its future development were also presented.

Experimental evidence for dual diffractive resonances in nucleon-nucleus scattering

International Nuclear Information System (INIS)

Ion, D.B.; Ion-Mihai, R.

1981-09-01

Experimental data on nucleon-nucleus scattering for laboratory momenta between 0.9:10 GeV/c are analysed in terms of the dual diffractive resonance (DDR) mechanism. The experimental data for all the nuclei are found to agree well with the predictions of the collective DDR states dominance. (authors)

Stimulated Brillouin scattering reduction induced by self-focusing for a single laser speckle interacting with an expanding plasma

International Nuclear Information System (INIS)

Masson-Laborde, P. E.; Depierreux, S.; Loiseau, P.; Hüller, S.; Pesme, D.; Labaune, Ch.; Bandulet, H.

2014-01-01

The origin of the low level of stimulated Brillouin scattering (SBS) observed in laser-plasma experiments carried out with a single laser speckle is investigated by means of three-dimensional simulations and modeling in the limit when the laser beam power P is well above the critical power for ponderomotive self-focusing We find that the order of magnitude of the time averaged reflectivities, together with the temporal and spatial SBS localization observed in our simulations, are correctly reproduced by our modeling. It is observed that, after a short transient stage, SBS reaches a significant level only (i) as long as the incident laser pulse is increasing in amplitude and (ii) in a single self-focused speckle located in the low-density front part of the plasma. In order to describe self-focusing in an inhomogeneous expanding plasma, we have derived a new Lagrangian density describing this process. Using then a variational approach, our model reproduces the position and the peak intensity of the self-focusing hot spot in the front part of the plasma density profile as well as the local density depletion in this hot spot. The knowledge of these parameters then makes it possible to estimate the spatial amplification of SBS as a function of the laser beam power and consequently to explain the experimentally observed SBS reflectivity, considerably reduced with respect to standard theory in the regime of large laser beam power

Efimov states near a Feshbach resonance and the limits of van der Waals universality at finite background scattering length

Science.gov (United States)

Langmack, Christian; Schmidt, Richard; Zwerger, Wilhelm

2018-03-01

We calculate the spectrum of three-body Efimov bound states near a Feshbach resonance within a model which accounts both for the finite range of interactions and the presence of background scattering. The latter may be due to direct interactions in an open channel or a second overlapping Feshbach resonance. It is found that background scattering gives rise to substantial changes in the trimer spectrum as a function of the detuning away from a Feshbach resonance, in particular in the regime where the background channel supports Efimov states on its own. Compared to the situation with negligible background scattering, the regime where van der Waals universality applies is shifted to larger values of the resonance strength if the background scattering length is positive. For negative background scattering lengths, in turn, van der Waals universality extends to even small values of the resonance strength parameter, consistent with experimental results on Efimov states in 39K. Within a simple model, we show that short-range three-body forces do not affect van der Waals universality significantly. Repulsive three-body forces may, however, explain the observed variation between around -8 and -10 of the ratio between the scattering length where the first Efimov trimer appears and the van der Waals length.

Single-particle resonance levels in {sup 14}O examined by N13+p elastic resonance scattering

Energy Technology Data Exchange (ETDEWEB)

Teranishi, T. [Dept. of Physics, Kyushu Univ., 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)]. E-mail: teranishi@nucl.phys.kyushu-u.ac.jp; Kubono, S. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamaguchi, H. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); He, J.J. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Saito, A. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Fujikawa, H. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Amadio, G. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Niikura, M.; Shimoura, S. [Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y. [Dept. of Physics, Kyushu Univ., 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)]|[Center for Nuclear Study (CNS), Univ. of Tokyo, Wako Branch at RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nishimura, S.; Nishimura, M. [RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Moon, J.Y.; Lee, C.S. [Dept. of Physics, Chung-Ang Univ., Seoul 156-756 (Korea, Republic of); Odahara, A. [Nishinippon Inst. of Technology, Kanda, Fukuoka 800-0394 (Japan); Sohler, D. [Inst. of Nuclear Research (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Khiem, L.H. [Inst. of Physics and Electronics (IOP), Vietnamese Academy for Science and Technology (VAST), 10 Daotan, Congvi, Badinh, P.O. Box 429-BOHO, Hanoi 10000 (Viet Nam); Li, Z.H.; Lian, G.; Liu, W.P. [China Inst. of Atomic Energy, P.O. Box 275(46), Beijing 102413 (China)

2007-06-28

Single-particle properties of low-lying resonance levels in {sup 14}O have been studied efficiently by utilizing a technique of proton elastic resonance scattering with a {sup 13}N secondary beam and a thick proton target. The excitation functions for the N13+p elastic scattering were measured over a wide energy range of E{sub CM}=0.4-3.3 MeV and fitted with an R-matrix calculation. A clear assignment of J{sup {pi}}=2{sup -} has been made for the level at E{sub x}=6.767(11) MeV in {sup 14}O for the first time. The excitation functions show a signature of a new 0{sup -} level at E{sub x}=5.71(2) MeV with {gamma}=400(100) keV. The excitation energies and widths of the {sup 14}O levels are discussed in conjunction with the spectroscopic structure of A=14 nuclei with T=1.

A Brillouin smart FRP material and a strain data post processing software for structural health monitoring through laboratory testing and field application on a highway bridge

Science.gov (United States)

Bastianini, Filippo; Matta, Fabio; Galati, Nestore; Nanni, Antonio

2005-05-01

Strain and temperature sensing obtained through frequency shift evaluation of Brillouin scattered light is a technology that seems extremely promising for Structural Health Monitoring (SHM). Due to the intrinsic distributed sensing capability, Brillouin can measure the deformation of any individual segment of huge lengths of inexpensive single-mode fiber. In addition, Brillouin retains other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and interference rejection. Despite these advantages, the diffusion of Brillouin for SHM is constrained by different factors, such as the high equipment cost, the commercial unavailability of specific SHM oriented fiber products and even some prejudices on the required sensitivity performances. In the present work, a complete SHM pilot application was developed, installed and successfully operated during a diagnostic load test on the High Performance Steel (HPS) bridge A6358 located at the Lake of the Ozarks (Miller County, MO, USA). Four out of five girders were extensively instrumented with a "smart" Glass Fiber Reinforced Polymer (GFRP) tape having embedded fibers for strain sensing and thermal compensation. Data collected during a diagnostic load test were elaborated through a specific post-processing software, and the strain profiles retrieved were compared to traditional strain gauges and theoretical results based on the AASHTO LRFD Bridge Design Specifications for structural assessment purposes. The excellent results obtained confirm the effectiveness of Brillouin SHM systems for the monitoring of real applications.

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

Science.gov (United States)

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.

Scattering tensors and optical transitions in Si and Ge

CSIR Research Space (South Africa)

Kunert, HW

2012-08-01

Full Text Available and L high symmetry points and the highest maximum of the valence band (VB) in the Brillouin zone of Oh7 space group symmetry are determined. The elements of El-Ph scattering tensors are linear combinations of the Clebsch-Gordon coefficients (CGC...

Study of the unbound proton-rich nucleus $^{21}$Al with resonance elastic and inelastic scattering using an active target

CERN Multimedia

We intend to measure the structure of the unbound nucleus $^{21}$Al via resonance elastic and inelastic scattering with an active target. There are many goals: \\\\ a) to locate the 1/2$^{+}$ level in $^{21}$Al that brings information on the Thomas-Ehrman shift, \\\\ b) to measure the energy spectrum of $^{21}$Al which is a N=8 isotone with the resonance elastic scattering reaction, \\\\ c) to investigate via inelastic scattering the strength of core excitations in the existence of narrow unbound resonances beyond the proton drip-line.

Parent state swapping of resonances in electron-hydrogen molecule scattering

International Nuclear Information System (INIS)

Stibbe, D.T.

1997-01-01

Ab initio R-matrix scattering calculations are presented for electron-H 2 as a function of H 2 bond length. It is found that 2 Σ u + and 2Π u resonances in the 10 eV region appear to be associated with multiple 'parent' target states and that the resonances can swap parents as a function of internuclear separation. It is shown how these phenomena provide an explanation for the inconsistencies in previous assignments of resonances in this region and other anomalies such as pronounced isotopic effects. It is suggested that this parent swapping behaviour is likely to be a common feature of electron-impact excitation of other molecules and is particularly important for any models that include nuclear motion. (author)

Uncertainty in the inelastic resonant scattering assisted by phonons

International Nuclear Information System (INIS)

Garcia, N.; Garcia-Sanz, J.; Solana, J.

1977-01-01

We have analyzed the inelastic minima observed in new results of He atoms scattered from LiF(001) surfaces. This is done considering bound state resonance processes assisted by phonons. The analysis presents large uncertainties. In the range of uncertainty, we find two ''possible'' bands associated with the vibrations of F - and Li + , respectively. Many more experimental data are necessary to confirm the existence of these processes

K-edge resonant x-ray magnetic scattering from a transition-metal oxide: NiO

DEFF Research Database (Denmark)

Hill, J.P.; Kao, C.C.; McMorrow, D.F.

1997-01-01

We report the observation of resonant x-ray magnetic scattering in the vicinity of the Ni K edge in the antiferromagnet NiO. An approximately twofold increase in the scattering is observed as the incident photon energy is tuned through a pre-edge feature in the absorption spectrum, associated...

Coupling effects of giant resonances on the elastic and inelastic scattering of fast neutrons

International Nuclear Information System (INIS)

Delaroche, J.P.; Tornow, W.

1983-01-01

While the inelastic scattering of high energy hadrons is commonly used for the study of giant resonances in nuclei, it is just recently that one has thought to take into account these states in the analysis of proton scattering at low incident energies (E 0 and S 1 . (Auth.)

Elastic properties of aspirin in its crystalline and glassy phases studied by micro-Brillouin scattering

Science.gov (United States)

Ko, Jae-Hyeon; Lee, Kwang-Sei; Ike, Yuji; Kojima, Seiji

2008-11-01

The acoustic waves propagating along the direction perpendicular to the (1 0 0) cleavage plane of aspirin crystal were investigated using micro-Brillouin spectroscopy from which C11, C55 and C66 were obtained. The temperature dependence of the longitudinal acoustic waves could be explained by normal anharmonic lattice models, while the transverse acoustic waves showed an abnormal increase in the hypersonic attenuation at low temperatures indicating their coupling to local remnant dynamics. The sound velocity as well as the attenuation of the longitudinal acoustic waves of glassy aspirin showed a substantial change at ˜235 K confirming a transition from glassy to supercooled liquid state in vitreous aspirin.

Resonant scattering induced thermopower in one-dimensional disordered systems

Science.gov (United States)

Müller, Daniel; Smit, Wilbert J.; Sigrist, Manfred

2015-05-01

This study analyzes thermoelectric properties of a one-dimensional random conductor which shows localization effects and simultaneously includes resonant scatterers yielding sharp conductance resonances. These sharp features give rise to a distinct behavior of the Seebeck coefficient in finite systems and incorporate the degree of localization as a means to enhance thermoelectric performance, in principle. The model for noninteracting electrons is discussed within the Landauer-Büttiker formalism such that analytical treatment is possible for a wide range of properties, if a special averaging scheme is applied. The approximations in the averaging procedure are tested with numerical evaluations showing good qualitative agreement, with some limited quantitative disagreement. The validity of low-temperature Mott's formula is determined and a good approximation is developed for the intermediate temperature range. In both regimes the intricate interplay between Anderson localization due to disorder and conductance resonances of the disorder potential is analyzed.

S-wave Kπ scattering in chiral perturbation theory with resonances

International Nuclear Information System (INIS)

Jamin, Matthias; Oller, Jose Antonio; Pich, Antonio

2000-01-01

We present a detailed analysis of S-wave Kπ scattering up to 2 GeV, making use of the resonance chiral Lagrangian predictions together with a suitable unitarisation method. Our approach incorporates known theoretical constraints at low and high energies. The present experimental status, with partly conflicting data from different experiments, is discussed. Our analysis allows to resolve some experimental ambiguities, but better data are needed in order to determine the cross-section in the higher-energy range. Our best fits are used to determine the masses and widths of the relevant scalar resonances in this energy region

Applications of phase conjugate mirror to Thomson scattering diagnostics (invited)

International Nuclear Information System (INIS)

Hatae, T.; Naito, O.; Nakatsuka, M.; Yoshida, H.

2006-01-01

A high performance phase conjugate mirror based on stimulated Brillouin scattering (SBS-PCM) has been applied to the Thomson scattering system in the JT-60U tokamak for the first time in order to improve the measurement performance. A SBS-PCM realized a high reflectivity of 95% at a high input power of 145 W (2.9 J, 50 Hz). Using the SBS-PCM, two methods have been developed to increase the intensity of scattered light. For the first method, we have developed a new optical design to provide a double-pass scattering method with the SBS-PCM. A laser beam passing through the plasma is reflected by the SBS-PCM. The reflected beam passes the plasma again along the same path by means of the phase conjugation of the optically nonlinear stimulated Brillouin scattering process. The double-pass Thomson scattering method using the SBS-PCM has demonstrated an increase of the scattered light by a factor of 1.6 compared with the single-pass scattering method in JT-60U. A multipass Thomson scattering method in which the laser beam can be confined between a couple of SBS-PCMs is also proposed. It is estimated that the multipass scattering method generates the scattered light more than several times as large as that of the single-pass scattering method. For the second method, a high-average-power yttrium aluminum garnet (Nd:YAG) laser system has been developed using the SBS-PCM. The SBS-PCM effectively compensated thermal degradation at two amplifier lines, and the average power was increased by a factor of >8 from 45 W (1.5 J, 30 Hz) to 373 W (7.46 J, 50 Hz). A Nd:YAG laser (5 J, 100 Hz) for the edge Thomson scattering in International Thermonuclear Experimental Reactor (ITER) has been designed based on the result

On the influence of resonance photon scattering on atom interference

International Nuclear Information System (INIS)

Bozic, M; Arsenovic, D; Sanz, A S; Davidovic, M

2010-01-01

Here, the influence of resonance photon-atom scattering on the atom interference pattern at the exit of a three-grating Mach-Zehnder interferometer is studied. It is assumed that the scattering process does not destroy the atomic wave function describing the state of the atom before the scattering process takes place, but only induces a certain shift and change of its phase. We find that the visibility of the interference strongly depends on the statistical distribution of transferred momenta to the atom during the photon-atom scattering event. This also explains the experimentally observed (Chapman et al 1995 Phys. Rev. Lett. 75 2783) dependence of the visibility on the ratio d p /λ i =y' 12 (2π/kdλ i ), where y' 12 is the distance between the place where the scattering event occurs and the first grating, k is the wave number of the atomic centre-of-mass motion, d is the grating constant and λ i is the photon wavelength. Furthermore, it is remarkable that photon-atom scattering events happen experimentally within the Fresnel region, i.e. the near-field region, associated with the first grating, which should be taken into account when drawing conclusions about the relevance of 'which-way' information for the interference visibility.

A small-angle camera for resonant scattering experiments at the storage ring DORIS

International Nuclear Information System (INIS)

Stuhrmann, H.B.; Gabriel, A.

1983-01-01

Resonant small-angle scattering is measured routinely in the wavelength range of 0.6 to 3.25 A with the instrument X15 at the storage ring DORIS. The monochromatic beam with a vertical offset of 1.22 m is achieved by a double monochromator system with a constant exit slit. The small-angle instrument allows for sample-detector distances between 0.37 and 7.33 m. A multiwire proportional counter with a sensitive area of 200 X 200 mm detects the scattered intensity with a spatial resolution of 2 X 2 mm. Its sensitivity can be adapted to the requirements of the experiment by activating a drift chamber of 8 cm depth at the back end of the detector. The performance of the instrument as a function of the wavelength is described. The energy resolution is about 1 eV at the L 3 absorption edge of caesium, as shown by the resonant scattering of ferritin in 30% CsCl solution. (Auth.)

Surface-enhanced Raman scattering (SERS) of riboflavin on nanostructured Ag surfaces: The role of excitation wavelength, plasmon resonance and molecular resonance

Science.gov (United States)

Šubr, Martin; Kuzminova, Anna; Kylián, Ondřej; Procházka, Marek

2018-05-01

Optimization of surface-enhanced Raman scattering (SERS)-based sensors for (bio)analytical applications has received much attention in recent years. For optimum sensitivity, both the nanostructure fabrication process and the choice of the excitation wavelength used with respect to the specific analyte studied are of crucial importance. In this contribution, detailed SERS intensity profiles were measured using gradient nanostructures with the localized surface-plasmon resonance (LSPR) condition varying across the sample length and using riboflavin as the model biomolecule. Three different excitation wavelengths (633 nm, 515 nm and 488 nm) corresponding to non-resonance, pre-resonance and resonance excitation with respect to the studied molecule, respectively, were tested. Results were interpreted in terms of a superposition of the enhancement provided by the electromagnetic mechanism and intrinsic properties of the SERS probe molecule. The first effect was dictated mainly by the degree of spectral overlap between the LSPR band, the excitation wavelength along with the scattering cross-section of the nanostructures, while the latter was influenced by the position of the molecular resonance with respect to the excitation wavelength. Our experimental findings contribute to a better understanding of the SERS enhancement mechanism.

The Over-Barrier Resonant States and Multi-Channel Scattering in Multiple Quantum Wells

Directory of Open Access Journals (Sweden)

A Polupanov

2016-09-01

Full Text Available We demonstrate an explicit numerical method for accurate calculation of the scattering matrix and its poles, and apply this method to describe the multi-channel scattering in the multiple quantum-wells structures. The S-matrix is continued analytically to the unphysical region of complex energy values. Results of calculations show that there exist one or more S-matrix poles, corresponding to the over-barrier resonant states critical for the effect of the absolute reflection of holes in the energy range where only the heavy ones may propagate over barriers in a structure. Light- and heavy-hole states are described by the Luttinger Hamiltonian matrix. In contrast to the single quantum-well case, at some parameters of a multiple quantum-wells structure the number of S-matrix poles may exceed that of the absolute reflection peaks, and at different values of parameters the absolute reflection peak corresponds to different resonant states. The imaginary parts of the S-matrix poles and hence the lifetimes of resonant states as well as the widths of resonant peaks of absolute reflection depend drastically on the quantum-well potential depth. In the case of shallow quantum wells there is in fact a long-living over-barrier resonant hole state.

Resonant Raman scattering in ion-beam-synthesized Mg2Si in a silicon matrix

International Nuclear Information System (INIS)

Baleva, M.; Zlateva, G.; Atanassov, A.; Abrashev, M.; Goranova, E.

2005-01-01

Resonant Raman scattering by ion beam synthesized in silicon matrix Mg 2 Si phase is studied. The samples are prepared with the implantation of 24 Mg + ions with dose 4x10 17 cm -2 and with two different energies 40 and 60 keV into (100)Si substrates. The far infrared spectra are used as criteria for the formation of the Mg 2 Si phase. The Raman spectra are excited with different lines of Ar + laser, with energies of the lines lying in the interval from 2.40 to 2.75 eV. The resonant scattering can be investigated using these laser lines, as far as according to the Mg 2 Si band structure, there are direct gaps with energies in the same region. The energy dependences of the scattered intensities in the case of the scattering by the allowed F 2g and the forbidden LO-type modes are experimentally obtained and theoretically interpreted. On the base of the investigation energies of the interband transitions in the Mg 2 Si are determined. It is found also that the resonant Raman scattering appears to be a powerful tool for characterization of a material with inclusions in it. In the particular case it is concluded that the Mg 2 Si phase is present in the form of a surface layer in the sample, prepared with implantation energy 40 keV and as low-dimensional precipitates, embedded in the silicon matrix, in the sample, prepared with the higher implantation energy

Photoexcitation by gamma-ray scattering near threshold and giant dipole resonance

International Nuclear Information System (INIS)

Lakosi, L.; Safar, J.; Veres, A.; Sekine, T.; Kaji, H.; Yoshihara, K.

1993-01-01

Photoexcitation of 4.5 h half-life 115m In and 56 min half-life 103m Rh isomers by inelastic gamma-ray scattering near threshold and in the giant dipole resonance region has been reviewed. In disagreement with earlier experimental results available in the literature, but in good agreement with our experiments published recently, present calculations indicate that above the photoneutron emission threshold the isomer excitation drops abruptly and remains orders of magnitude smaller than at the threshold, even around resonance maximum. (author)

Electron scattering from CO in the 2Pi resonance region

International Nuclear Information System (INIS)

Buckman, S.J.; Lohmann, B.

1986-01-01

The total cross section for electron scattering from CO in the energy range 0.5--5 eV has been measured with use of a time-of-flight spectrometer. This energy region encompasses the 2 π shape resonance, and a comparison is made with other experimental and theoretical results with regard to the magnitude and position of this structure

Strange resonance poles from Kπ scattering below 1.8 GeV

Energy Technology Data Exchange (ETDEWEB)

Pelaez, J.R.; Rodas, A. [Universidad Complutense de Madrid, Departamento de Fisica Teorica II, Madrid (Spain); Ruiz de Elvira, J. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); University of Bern, Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Bern (Switzerland)

2017-02-15

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{sub 0}{sup *}(800), the scalar K{sub 0}{sup *}(1430), the K*(892) and K{sub 1}{sup *}(1410) vectors, the spin-two K{sub 2}{sup *}(1430) as well as the spin-three K{sup *}{sub 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 Pade approximants, thus avoiding a particular model for the pole parameterization. We also pay particular attention to the evaluation of uncertainties. (orig.)

Electron scattering from H2+: Resonances in the Σ and Π symmetries

International Nuclear Information System (INIS)

Collins, L.A.; Schneider, B.I.; Lynch, D.L.; Noble, C.J.

1995-01-01

We present results of calculations for e - +H 2 + scattering in the energy regime below the first excited state for resonance symmetries Σ and Π. We employ three distinct and independent methods: close-coupling linear algebraic, effective optical potential linear algebraic, and R matrix. We report extended calculations on the 1 Π g resonance, important to dissociative recombination. We show binding of the 1 Σ g state resonance between 2.6 and 2.7 bohrs. Our 1 Σ u state results agree very well with previous calculations and reside a factor of 2 below a recent experiment

Electron scattering by an atom in the field of resonant laser radiation

International Nuclear Information System (INIS)

Agre, M.; Rapoport, L.

1982-01-01

The collision of an electron with an atom in the field of intense electromagnetic radiation that is at resonance with two atomic multiplets is investigated theoretically. Expressions are obtained for the amplitudes of the elastic and inelastic scattering with emission (absorption) of photons. The case of a ground state at resonance with a doublet is considered in detail. It is shown that photon absorption takes place predominantly in the case of resonance in inelastic transitions from a state of the lower multiplet, and photon emission takes place in transitions from a state of the upper multiplet

Resonance scattering spectra of micrococcus lysodeikticus and its application to assay of lysozyme activity.

Science.gov (United States)

Jiang, Zhi-Liang; Huang, Guo-Xia

2007-02-01

Several methods, including turbidimetric and colorimetric methods, have been reported for the detection of lysozyme activity. However, there is no report about the resonance scattering spectral (RSS) assay, which is based on the catalytic effect of lysozyme on the hydrolysis of micrococcus lysodeikticus (ML) and its resonance scattering effect. ML has 5 resonance scattering peaks at 360 400, 420, 470, and 520 nm with the strongest one at 470 nm. The concentration of ML in the range of 2.0x10(6)-9.3x10(8) cells/ml is proportional to the RS intensity at 470 nm (I(470 nm)). A new catalytic RSS method has been proposed for 0.24-40.0 U/ml (or 0.012-2.0 mug/ml) lysozyme activity, with a detection limit (3sigma) of 0.014 U/ml (or 0.0007 microg/ml). Saliva samples were assayed by this method, and it is in agreement with the results of turbidimetric method. The slope, intercept and the correlation coefficient of the regression analysis of the 2 assays were 0.9665, -87.50, and 0.9973, respectively. The assay has high sensitivity and simplicity.

Characterization of excited electronic states of naphthalene by resonance Raman and hyper-Raman scattering

International Nuclear Information System (INIS)

Bonang, C.C.; Cameron, S.M.

1992-01-01

The first resonance Raman and hyper-Raman scattering from naphthalene are reported. Fourth harmonic of a mode-locked Nd:YAG laser is used to resonantly excite the 1 B 1u + transition, producing Raman spectra that confirm the dominance of the vibronically active ν 28 (b 3g ) mode and the Franck--Condon active a g modes, ν 5 and ν 3 . A synchronously pumped stilbene dye laser and its second harmonic are employed as the excitation sources for hyper-Raman and Raman scattering from the overlapping 1 B 2 u + and 1 A g - states. The Raman spectra indicate that the equilibrium geometry of naphthalene is distorted primarily along ν 5 , ν 8 , and ν 7 normal coordinates upon excitation to 1 B 2 u + . The hyper-Raman spectrum shows that ν 25 (b 2u ) is the mode principally responsible for vibronic coupling between the 1 A g - and 1 B 2u + states. The results demonstrate the advantageous features of resonance hyper-Raman scattering for the case of overlapping one- and two-photon allowed transitions. Calculations based on simple molecular orbital configurations are shown to qualitatively agree with the experimental results

Experimental study on stimulated scattering of ZnO nanospheres dispersed in water

Energy Technology Data Exchange (ETDEWEB)

Shi, Jiulin, E-mail: hyq1304@126.com; Wu, Haopeng [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China); Yan, Feng; Yang, Junjie [Nanchang Hangkong University, School of Measuring and Optical Engineering (China); He, Xingdao, E-mail: xingdaohe@126.com [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China)

2016-01-15

The backward stimulated scattering (BSS) from ZnO nanospheres dispersed in water has been investigated experimentally by employing a Nd:YAG pulse laser with ∼532 nm wavelength and ∼8 ns pulse width as the pump laser source. The present results show that the BSS effect is uniquely and unequivocally different compared to other known stimulated scattering, such as stimulated Rayleigh scattering, stimulated Brillouin scattering, and stimulated Raman scattering, and it displays the characteristics of no frequency shift and threshold dependence on initial spontaneous Mie scattering seed source. These can be understood by means of the Mie scattering theory and a laser-induced stationary Bragg grating model.

Excitation of giant monopole resonance in {sup 208}Pb and {sup 116}Sn using inelastic deuteron scattering

Energy Technology Data Exchange (ETDEWEB)

Patel, D.; Garg, U. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); GANIL, CEA/DSM-CNRS/IN2P3, 14076 Caen (France); Iwamoto, C. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Kawabata, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Kawase, K. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Matta, J.T. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Murakami, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Okamoto, A. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Sako, T. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Schlax, K.W. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Takahashi, F. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); White, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)

2014-07-30

The excitation of the isoscalar giant monopole resonance (ISGMR) in {sup 208}Pb and {sup 116}Sn has been investigated using small-angle (including 0°) inelastic scattering of 100 MeV/u deuteron and multipole-decomposition analysis (MDA). The extracted strength distributions agree well with those from inelastic scattering of 100 MeV/u α particles. These measurements establish deuteron inelastic scattering at E{sub d}∼100 MeV/u as a suitable probe for extraction of the ISGMR strength with MDA, making feasible the investigation of this resonance in radioactive isotopes in inverse kinematics.

The Van der Waals-force-induced phononic band gap and resonant scattering in two-nanosphere aggregate

International Nuclear Information System (INIS)

Wu Jiuhui; Zhang Siwen; Zhou Kejiang

2012-01-01

A physical mechanism of phononic band gap and resonant nanoacoustic scattering in an aggregate of two elastic nanospheres is presented in this paper. By considering the Van der Waals (VdW) force between two nanospheres illuminated by nanoacoustic wave, phononic band gap and frequency shift at the lower frequency side, and largely enhanced nanoacoustic scattering at the other frequency range have been found through calculating the form function of the acoustic scattering from the nanosystem. This VdW-force-induced band gap is different from the known mechanisms of Bragg scattering and local resonances for periodic media. It is shown that when the separation distance between two nanospheres is decreasing from 20 to 1 nm, due to the increasing VdW force, the nanoacoustic scattering is much heightened by two order of magnitude, and meanwhile the frequency shift and phononic band gap at the low frequencies are both widened. These results could provide potential applications of nanoacoustic devices.

An exploration in acoustic radiation force experienced by cylindrical shells via resonance scattering theory.

Science.gov (United States)

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.

Robust, Brillouin Active Embedded Fiber-Is-The-Sensor System in Smart Composite Structures

Science.gov (United States)

Yu, Chung

1996-01-01

Extensive review of our proposed sensing scheme, based mainly on the forward Guided Acoustic Wave Brillouin Scattering (GAWBS) with backward stimulated Brillouin scattering (sBs) as an auxiliary scheme for system fault tolerance has been completed during this project period. This preliminary study is conducted for a number of reasons. The most significant reasons lie in the essential capability of the system to measure temperature and pressure. These two measurands have been proposed to be sensed by sBs in our proposal. Temperature and pressure/strain are important measurands in structural monitoring, so that the effectiveness of sensing by sBs needs to be further examined. It has been pointed out initially that sBs shift will be dependent on temperature and pressure/strain simultaneously. The shift versus temperature or strain is linear. Now, the question is how can these two measurands be separated when sBs is used to sense an environment, in which both temperature and strain are changing simultaneously. Typical sBs shift plotted versus strain and varying temperature is shown in Fig. 1. As is clear, a fiber initially stressed will relax with rising temperature. This is verified by a displacement to the right with rising temperature of the sBs shift vs strain curves in the figure. A way to circumvent this ambiguity is by employing two fibers, one pre-stressed and the other is a free fiber. The latter will measure temperature and subtracting data in the latter fiber from those of the former will give us net strain readings. This is a laborious approach, since it involves the use of two identical fibers, and this is hard to accomplish, especially when many sensors are needed. Additional multiplexing of the data stream for data subtraction becomes a necessity.

Stability of Brillouin flow in planar, conventional, and inverted magnetrons

International Nuclear Information System (INIS)

Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Gilgenbach, R. M.; Hoff, B. W.

2015-01-01

The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions

Resonant x-ray scattering study of the antiferroelectric and ferrielectric phases in liquid crystal devices

International Nuclear Information System (INIS)

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.

2001-01-01

Resonant x-ray scattering has been used to investigate the interlayer ordering of the antiferroelectric and ferrielectric smectic C * 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

Simulation of simultaneously obtaining ocean temperature and salinity using dual-wavelength Brillouin lidar

International Nuclear Information System (INIS)

Yu, Yin; Ma, Yong; Li, Hao; Huang, Jun; Fang, Yu; Liang, Kun; Zhou, Bo

2014-01-01

A method for simultaneously obtaining the ocean temperature and salinity based on dual-wavelength Brillouin lidar is proposed in this letter. On the basis of the relationships between the temperature and salinity and the Brillouin shifts, a retrieval model for retrieving the temperature and salinity is established. By using the retrieval model, the ocean temperature and salinity can be simultaneously obtained through the Brillouin shifts. Simulation based on dual-wavelength Brillouin lidar is also carried out for verification of the accuracy of the retrieval model. Results show that the errors of the retrieval model for temperature and salinity are ±0.27 °C and ±0.33‰. (letter)

Study of the giant multipole resonances, especially the isoscalar giant E2 resonance in 208Pb by inelastic electron scattering with medium and high energy resolution

International Nuclear Information System (INIS)

Kuehner, E.G.F.

1982-01-01

In the nucleus 208 Pb giant multipole resonances were looked for by inelastic electron scattering up to excitation energies of Esub(x) = 35 MeV. Twelve spectra were taken up at incident energies of Esub(o) = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. Basing on this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as a superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forwards angles a further weak excitation appears at Esub(x) approx.= 14.6 MeV which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is also observed in (α,α') scattering experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also Jsup(π) = 3 - character but has partly to be assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gels because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

Micro-focused Brillouin light scattering study of the magnetization dynamics driven by Spin Hall effect in a transversely magnetized NiFe nanowire

Energy Technology Data Exchange (ETDEWEB)

Madami, M., E-mail: marco.madami@fisica.unipg.it; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Moriyama, T.; Tanaka, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Kyoto (Japan); Siracusano, G.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, Bari (Italy)

2015-05-07

We employed micro-focused Brillouin light scattering to study the amplification of the thermal spin wave eigenmodes by means of a pure spin current, generated by the spin-Hall effect, in a transversely magnetized Pt(4 nm)/NiFe(4 nm)/SiO{sub 2}(5 nm) layered nanowire with lateral dimensions 500 × 2750 nm{sup 2}. The frequency and the cross section of both the center (fundamental) and the edge spin wave modes have been measured as a function of the intensity of the injected dc electric current. The frequency of both modes exhibits a clear redshift while their cross section is greatly enhanced on increasing the intensity of the injected dc. A threshold-like behavior is observed for a value of the injected dc of 2.8 mA. Interestingly, an additional mode, localized in the central part of the nanowire, appears at higher frequency on increasing the intensity of the injected dc above the threshold value. Micromagnetic simulations were used to quantitatively reproduce the experimental results and to investigate the complex non-linear dynamics induced by the spin-Hall effect, including the modification of the spatial profile of the spin wave modes and the appearance of the extra mode above the threshold.

Resonant X-ray Scattering of carbonyl sulfide at the sulfur K edge

International Nuclear Information System (INIS)

Journel, Loïc; Marchenko, Tatiana; Guillemin, Renaud; Kawerk, Elie; Simon, Marc; Kavčič, Matjaž; Žit-nik, Matjaž; Bučar, Klemen; Bohinc, Rok

2015-01-01

New results on free OCS molecules have been obtained using Resonant X-ray Inelastic Scattering spectroscopy. A deconvolution algorithm has been applied to improve the energy resolution spectra of which we can extract detailed information on nuclear dynamics in the system. (paper)

Resonant X-ray Scattering of carbonyl sulfide at the sulfur K edge

OpenAIRE

Journel , Loïc; Marchenko , Tatiana; Guillemin , Renaud; Kawerk , Elie; Kavčič , Matjaž; Žit-nik , Matjaž; Bučar , Klemen; Bohinc , Rok; Simon , Marc

2015-01-01

International audience; New results on free OCS molecules have been obtained using Resonant X-ray Inelastic Scattering spectroscopy. A deconvolution algorithm has been applied to improve the energy resolution spectra of which we can extract detailed information on nuclear dynamics in the system.

Applications of the Hybrid Theory to the Scattering of Electrons from HE+ and Li++ and Resonances in these Systems

Science.gov (United States)

Bhatia, Anand K.

2008-01-01

Applications of the hybrid theory to the scattering of electrons from Ile+ and Li++ and resonances in these systems, A. K. Bhatia, NASA/Goddard Space Flight Center- The Hybrid theory of electron-hydrogen elastic scattering [I] is applied to the S-wave scattering of electrons from He+ and Li++. In this method, both short-range and long-range correlations are included in the Schrodinger equation at the same time. Phase shifts obtained in this calculation have rigorous lower bounds to the exact phase shifts and they are compared with those obtained using the Feshbach projection operator formalism [2], the close-coupling approach [3], and Harris-Nesbet method [4]. The agreement among all the calculations is very good. These systems have doubly-excited or Feshbach resonances embedded in the continuum. The resonance parameters for the lowest ' S resonances in He and Li+ are calculated and they are compared with the results obtained using the Feshbach projection operator formalism [5,6]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances and the continuum in which these resonances are embedded.

On the Possibility of Resonances in Longitudinally Polarized Vector Boson Scattering

NARCIS (Netherlands)

Veltman, M.J.G.; Veltman, H.

1991-01-01

Assuming that no Higgs has been found below 1 TeV, we study the physics of longitudinally polarized vector boson ( ) scattering in the TeV region, using a one loop calculation and partial wave analysis. We show that the occurrence of a resonance in the isospin I = 1 channel depends on a certain

Understanding of increased diffuse scattering in regular arrays of fluctuating resonant particles

DEFF Research Database (Denmark)

Andryieuski, Andrei; Petrov, Mihail; Lavrinenko, Andrei

2015-01-01

In this presentation we will discuss the analytical and numerical approaches to modeling electromagnetic properties of geometrically regular subwavelength 2D arrays of random resonant plasmonic particles. Amorphous metamaterials and metasurfaces attract interest of the scientific community due...... with regular periodic arrangements of resonant nanoparticles of random polarizability/size/material at normal plane-wave incidence. We show that randomness of the polarizability is related to increase in diffused scattering and we relate this phenomenon to a modification of the dipoles’ interaction constant...

Non-local effect in Brillouin optical time-domain analyzer based on Raman amplification

International Nuclear Information System (INIS)

Jia Xinhong; Rao Yunjiang; Wang Zinan; Zhang Weili; Ran Zengling; Deng Kun; Yang Zixin

2012-01-01

Compared with conventional Brillouin optical time-domain analyzer (BOTDA), the BOTDA based on Raman amplification allows longer sensing range, higher signal-to-noise ratio and higher measurement accuracy. However, the non-local effect induced by pump depletion significantly restricts the probe optical power injected to sensing fiber, thereby limiting the further extension for sensing distance. In this paper, the coupled equations including the interaction of probe light, Brillouin and Raman pumps are applied to the study on the non-local characteristics of BOTDA based on Raman amplification. The results show that, the system error induced by non-local effect worsens with increased powers of probe wave and Raman pump. The frequency-division-multiplexing (cascading the fibers with various Brillouin frequency shifts) and time-division-multiplexing (modulating both of the Brillouin pump and probe lights) technologies are efficient approaches to suppress the non-local effect, through shortening the effective interaction range between Brillouin pump and probe lights. (authors)

Invited Article: Acousto-optic finite-difference frequency-domain algorithm for first-principles simulations of on-chip acousto-optic devices

Directory of Open Access Journals (Sweden)

Yu Shi

2017-02-01

Full Text Available We introduce a finite-difference frequency-domain algorithm for coupled acousto-optic simulations. First-principles acousto-optic simulation in time domain has been challenging due to the fact that the acoustic and optical frequencies differ by many orders of magnitude. We bypass this difficulty by formulating the interactions between the optical and acoustic waves rigorously as a system of coupled nonlinear equations in frequency domain. This approach is particularly suited for on-chip devices that are based on a variety of acousto-optic interactions such as the stimulated Brillouin scattering. We validate our algorithm by simulating a stimulated Brillouin scattering process in a suspended waveguide structure and find excellent agreement with coupled-mode theory. We further provide an example of a simulation for a compact on-chip resonator device that greatly enhances the effect of stimulated Brillouin scattering. Our algorithm should facilitate the design of nanophotonic on-chip devices for the harnessing of photon-phonon interactions.

Scattering of electromagnetic pulses by metal nanospheres in the vicinity of a Fano-like resonance

International Nuclear Information System (INIS)

Astapenko, V.A.; Svita, S.Yu.

2015-01-01

In the work, radiation scattering by metal nanospheres in a dielectric matrix in case of ultrashort and long electromagnetic pulses is studied theoretically. Spectral efficiencies of backward and forward scattering by silver nanospheres in glass are calculated with the use of experimental data on the dielectric permittivity of silver. The presence of Fano-like resonances in spectral dependences of scattering efficiency caused by interference of dipole and quadrupole scatterings is shown. Backward and forward scattering of ultrashort pulses is calculated and analyzed. The obtained dependences of the total probability of scattering (during all time of the action of a pulse) on pulse duration demonstrate an essential distinction between an ultrashort case and a long pulse limit

Resonant x-ray scattering in manganites: study of the orbital degree of freedom

International Nuclear Information System (INIS)

Ishihara, Sumio; Maekawa, Sadamichi

2002-01-01

The orbital degree of freedom of electrons and its interplay with spin, charge and lattice degrees of freedom are some of the central issues in colossal magnetoresistive manganites. The orbital degree of freedom has until recently remained hidden, since it does not couple directly to most experimental probes. Development of synchrotron light sources has changed the situation; by the resonant x-ray scattering (RXS) technique the orbital ordering has successfully been observed. In this article, we review progress in the recent studies of RXS in manganites. We start with a detailed review of the RXS experiments applied to the orbital-ordered manganites and other correlated electron systems. We derive the scattering cross section of RXS, where the tensor character of the atomic scattering factor (ASF) with respect to the x-ray polarization is stressed. Microscopic mechanisms of the anisotropic tensor character of the ASF are introduced and numerical results of the ASF and the scattering intensity are presented. The azimuthal angle scan is a unique experimental method to identify RXS from the orbital degree of freedom. A theory of the azimuthal angle and polarization dependence of the RXS intensity is presented. The theoretical results show good agreement with the experiments in manganites. Apart from the microscopic description of the ASF, a theoretical framework of RXS to relate directly to the 3d orbital is presented. The scattering cross section is represented by the correlation function of the pseudo-spin operator for the orbital degree of freedom. A theory is extended to the resonant inelastic x-ray scattering and methods to observe excitations of the orbital degree of freedom are proposed. (author)

Cyclotron resonant scattering in the spectra of gamma-ray bursts

International Nuclear Information System (INIS)

Lamb, D.Q.; Wang, J.C.L.; Loredo, T.J.; Wasserman, I.; Fenimore, E.E.

1989-01-01

Data on the GB880205 gamma-ray bursts are presented that have implications for the nature of gamma-ray burst sources. It is shown that cyclotron resonant scattering and Raman scattering account well for the positions, strengths, and shapes of the relative strengths of the first and second harmonics and their narrow widths. These results imply the existence of a superstrong (B of about 2 x 10 to the 12th G) magnetic field in the vicinity of the X-ray emission region of GB880205. Such a superstrong magnetic field points to a strongly magnetic neutron star as the origin of gamma-ray bursts, and to the fact that the gamma-ray sources belong to the Galaxy. 59 refs

RESONANCES IN THE ISOVECTOR P WAVE OF pi pi SCATTERING

Czech Academy of Sciences Publication Activity Database

Bydžovský, Petr; Surovtsev, Yu .S.; Kaminski, R.; Nagy, M.

2011-01-01

Roč. 26, 3-4 (2011), s. 634-635 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : Pion-pion scattering * mesonic resonances * multichannel analysis Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011

Inelastic neutron scattering from glass formers

International Nuclear Information System (INIS)

Buchenau, U.

1997-01-01

Neutron spectra below and above the glass transition temperature show a pronounced difference between strong and fragile glass formers in Angell's fragility scheme. The strong anharmonic increase of the inelastic scattering with increasing temperature in fragile substances is absent in the strongest glass former SiO 2 . That difference is reflected in the temperature dependence of Brillouin sound velocities above the glass transition. Coherent inelastic neutron scattering data indicate a mixture of sound waves and local modes at the low frequency boson peak. A relation between the fragility and the temperature dependence of the transverse hypersound velocity at the glass temperature is derived. (author)

Scattering resonances of ultracold atoms in confined geometries

International Nuclear Information System (INIS)

Saeidian, Shahpoor

2008-01-01

Subject of this thesis is the investigation of the quantum dynamics of ultracold atoms in confined geometries. We discuss the behavior of ground state atoms inside a 3D magnetic quadrupole field. Such atoms in enough weak magnetic fields can be approximately treated as neutral point-like particles. Complementary to the well-known positive energy resonances, we point out the existence of short-lived negative energy resonances. The latter originate from a fundamental symmetry of the underlying Hamiltonian. We drive a mapping of the two branches of the spectrum. Moreover, we analyze atomic hyperfine resonances in a magnetic quadrupole field. This corresponds to the case for which both the hyperfine and Zeeman interaction, are comparable, and should be taken into account. Finally, we develop a general grid method for multichannel scattering of two atoms in a two-dimensional harmonic confinement. With our approach we analyze transverse excitations/deexcitations in the course of the collisional process (distinguishable or identical atoms) including all important partial waves and their couplings due to the broken spherical symmetry. Special attention is paid to suggest a non-trivial extension of the CIRs theory developed so far only for the single-mode regime and zero-energy limit. (orig.)

Scattering resonances of ultracold atoms in confined geometries

Energy Technology Data Exchange (ETDEWEB)

Saeidian, Shahpoor

2008-06-18

Subject of this thesis is the investigation of the quantum dynamics of ultracold atoms in confined geometries. We discuss the behavior of ground state atoms inside a 3D magnetic quadrupole field. Such atoms in enough weak magnetic fields can be approximately treated as neutral point-like particles. Complementary to the well-known positive energy resonances, we point out the existence of short-lived negative energy resonances. The latter originate from a fundamental symmetry of the underlying Hamiltonian. We drive a mapping of the two branches of the spectrum. Moreover, we analyze atomic hyperfine resonances in a magnetic quadrupole field. This corresponds to the case for which both the hyperfine and Zeeman interaction, are comparable, and should be taken into account. Finally, we develop a general grid method for multichannel scattering of two atoms in a two-dimensional harmonic confinement. With our approach we analyze transverse excitations/deexcitations in the course of the collisional process (distinguishable or identical atoms) including all important partial waves and their couplings due to the broken spherical symmetry. Special attention is paid to suggest a non-trivial extension of the CIRs theory developed so far only for the single-mode regime and zero-energy limit. (orig.)

Resonating-group study of p + α scattering from 68 to 125 MeV

International Nuclear Information System (INIS)

Thompson, D.R.; Brown, R.E.; LeMere, M.; Tang, Y.C.

1977-01-01

The resonating-group method, together with a phenomenological consideration of reaction effects, is used to analyze p + α scattering data at the relatively high c.m. energies of 68, 80, and 124.8 MeV. The nucleon-nucleon potential employed contains a weakly repulsive core and yields a reasonably satisfactory description of not only the two-nucleon scattering data but also the essential properties of the α particle. The result shows that satisfactory agreement with experiment can be obtained. In particular, it is found that, because of the use of a totally antisymmetric wave function, the scattering behavior at large angles is adequately described

Sound velocities and hypersonic dampings of Pb[(Mg1/3Nb2/3)0.45Ti0.55]O3 single crystals studied by Brillouin light scattering.

Science.gov (United States)

Ko, Jae-Hyeon; Kim, Tae Hyun; Kojima, Seiji; Bokov, Alexei A; Ye, Zuo-Guang

2010-12-08

A Brillouin spectroscopic investigation was carried out on PMN-55%PT single crystals, which are known to have no chemically ordered regions and undergo a well-defined structural phase transition at T(C) ∼ 521 K. The longitudinal and transverse sound velocities probed on a right-angle scattering geometry exhibited a remarkable softening and increasing hypersonic damping on approaching T(C) from T(B) ∼ 610 K that was characterized by the deviation of the dielectric permittivity from the high-temperature Curie-Weiss behavior. The acoustic anomalies of the longitudinal acoustic mode at the backward scattering were more substantial than those observed at the right-angle scattering, which could be understood in the framework of normal acoustic dispersion considering the difference in the acoustic frequency. The softening of the transverse sound velocity was more significant than that of the longitudinal one upon cooling toward T(C), suggesting that this acoustic anomaly may be related to the local rhombohedral transformation, occurring in polar nano-regions (PNRs). The observed acoustic behaviors combined with the central peak dynamics clearly indicated the existence of dynamic polar nano-regions in PMN-55%PT where there are no chemically ordered regions, and seem to suggest that the order parameter fluctuations due to two kinds of coupling contribute to the acoustic anomalies in the temperature range of T(C) ∼ T(B): electrostrictive coupling between the acoustic waves and the dynamic PNRs, and linear coupling between the acoustic waves and the precursor polar clusters, i.e., the ordering unit responsible for the order-disorder-type slowing down behavior probed by the central peak.

Sonochemical synthesis and resonance light scattering effect of Zn(II)bis(1-(2-pyridylazo)-2-naphthol) nanorods

International Nuclear Information System (INIS)

Pan Hongcheng; Liang Fupei; Mao Changjie; Zhu Junjie

2007-01-01

Zn(II)bis(1-(2-pyridylazo)-2-naphthol) (Zn(PAN) 2 ) complex nanorods have been successfully synthesized via a facile sonochemical method. The transmission electron microscopy (TEM) images showed that the products had a rod-like morphology with a diameter of about 20-70 nm and a length of about 100-300 nm. The Zn(PAN) 2 nanorods exhibit an intense resonance light-scattering (RLS) effect, displaying a very strong RLS peak at 622 nm, a moderate peak at 361 nm and several broad bands ranged from 400 to 550 nm. The effect of ultrasonic irradiation and the mechanism of aggregation growth and resonance-enhanced light scattering were also discussed. Exciton coupling among neighbour Zn(PAN) 2 complex monomers in the nanorods were found to produce resonance-enhanced light scattering. The red-shifted absorption bands and depolarized RLS data can be explained in terms of a J-aggregate geometry of Zn(PAN) 2

Dual Raman-Brillouin spectroscopic investigation of plant stress response and development

Science.gov (United States)

Coker, Zachary; Troyanova-Wood, Maria; Marble, Kassie; Yakovlev, Vladislav

2018-03-01

Raman and Brillouin spectroscopy are powerful tools for non-invasive and non-destructive investigations of material chemical and mechanical properties. In this study, we use a newly developed custom-built dual Raman-Brillouin microspectroscopy instrument to build on previous works studying in-vivo stress response of live plants using only a Raman spectroscopy system. This dual Raman-Brillouin spectroscopy system is capable of fast simultaneous spectra acquisition from single-point locations. Shifts and changes in a samples Brillouin spectrum indicate a change in the physical characteristics of the sample, namely mechano-elasticity; in measuring this change, we can establish a relationship between the mechanical properties of a sample and known stress response agents, such as reactive oxygen species and other chemical constituents as indicated by peaks in the Raman spectra of the same acquisition point. Simultaneous application of these spectroscopic techniques offers great promise for future development and applications in agricultural and biological studies and can help to improve our understanding of mechanochemical changes of plants and other biological samples in response to environmental and chemically induced stresses at microscopic or cellular level.

Inelastic scattering of 9Be of 27 MeV/A to giant resonances

International Nuclear Information System (INIS)

Lebrun, D.; Buenerd, M.; Bini, M.; Harvey, B.G.; Legrain, R.; Mahoney, J.; Symons, T.J.M.; Van Bibber, K.

1980-07-01

Inelastic scattering spectra have been measured with 245 MeV incident energy 9 Be ions, on 208 Pb target. They show large excitation of the 208 Pb giant quadrupole resonance. DWBA calculations are reported and compared with the data

An unusually strong resonant phonon scattering by 3-d impurities in II-VI semiconductors

Energy Technology Data Exchange (ETDEWEB)

Lonchakov, A.T.; Sokolov, V.I.; Gruzdev, N.B. [Institute of Metal Physics, Russian Academy of Sciences, Ural Branch, S. Kovalevskaya Str. 18, 620219 Ekaterinburg (Russian Federation)

2004-11-01

Low temperature phonon heat conductivity was measured for ZnSe and ZnS crystals, doped with 3-d impurities. A strong resonance-like phonon scattering by 3-d ions with orbitally degenerate ground state was observed. The Jahn-Teller effect is proposed as the reason of the strong resonance-like behaviour of heat conductivity. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Laser scattering off of alpha particle cyclotron harmonic resonances: Annual performance report

International Nuclear Information System (INIS)

Aamodt, R.E.

1988-01-01

The active probing of burning plasmas to quantitatively determine high energy alpha particle characteristics is the main purpose of the laser and gyroton scattering program. Progress to date includes a systematic evaluation of homogeneous results, analytical study of alpha particle harmonic resonances, and investigations of finite size detection systems

Electron dynamics in the core-excited CS 2 molecule revealed through resonant inelastic x-ray scattering spectroscopy

OpenAIRE

Marchenko , T; Carniato , S; Journel , L; Guillemin , R; Kawerk , E; Žitnik , M; Kavčič , M; Bučar , K; Bohinc , R; Petric , M; da Cruz , V Vaz; Gel'mukhanov , F; Simon , Marielle

2015-01-01

International audience; We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the CS2 molecule near the S 1s edge. We show that localization of the S 1s core-hole occurs in CS2 during the RIXS process due to the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Strong evolution of the RIXS profile with the excitation energy far below the first absorption resonance reflects the onset of electron dynamics tr...

Resonant vibrations of self-interstitials in fcc metals with application to specific heat and neutron scattering

International Nuclear Information System (INIS)

Ram, P.N.; Dederichs, P.H.

1981-07-01

Some aspects of resonant vibrations of self-interstitials in the 100-dumbbell configuration in fcc-metals are discussed by extending previous calculations of Zeller et al. and Schober et al. Employing a simple defect model with nearest-neighbour interaction the local frequency spectrum of the defect is calculated showing several localized modes and low-frequency resonant modes. The change in the total density of states due to the defects is expressed as the derivative of a generalized phase shift which is used to calculate the change in the lattic specific heat due to single interstitials. Inelastic neutron scattering away from the one-phonon lines is proposed as a method to observe the resonant modes induced by self-interstitials. The model calculation in Cu shows that the well defined resonant modes due to dumbbell vibrations have appreciable intensity and could presumably be detected in neutron scattering measurements. The effect of di-interstitials on the phonon dispersion in Al is also discussed. (orig./GSCH)

Basis for calculating cross sections for nuclear magnetic resonance spin-modulated polarized neutron scattering.

Science.gov (United States)

Kotlarchyk, Michael; Thurston, George M

2016-12-28

In this work we study the potential for utilizing the scattering of polarized neutrons from nuclei whose spin has been modulated using nuclear magnetic resonance (NMR). From first principles, we present an in-depth development of the differential scattering cross sections that would arise in such measurements from a hypothetical target system containing nuclei with non-zero spins. In particular, we investigate the modulation of the polarized scattering cross sections following the application of radio frequency pulses that impart initial transverse rotations to selected sets of spin-1/2 nuclei. The long-term aim is to provide a foundational treatment of the scattering cross section associated with enhancing scattering signals from selected nuclei using NMR techniques, thus employing minimal chemical or isotopic alterations, so as to advance the knowledge of macromolecular or liquid structure.

Resonant soft x-ray scattering and charge density waves in correlated systems

NARCIS (Netherlands)

Rusydi, Andrivo

2006-01-01

Summary This work describes results obtained on the study of charge density waves (CDW) in strongly correlated systems with a new experimental method: resonant soft x-ray scattering (RSXS). The basic motivation is the 1986 discovery by Bednorz and Müler of a new type of superconductor, based on Cu

Measurements and applications of neutron multiple scattering in resonance region

International Nuclear Information System (INIS)

Ohkubo, Makio

1977-02-01

Capture yield of neutrons impinging on a thick material is complicated due to self-shielding and multiple scattering, especially in the resonance region. When the incident neutron energy is equal to a resonance energy of the material, capture probability of the neutron increases with sample thickness and reaches a saturation value P sub(CO). There is a simple relation between P sub(CO) and GAMMA sub(n)/GAMMA and the recoil energy by the Monte-Carlo calculation. To examine validity of the relation, P sub(CO) was measured for 19 resonances in 12 nuclides with thick samples, using a JAERI linac time-of-flight spectrometer with Moxon-Rae type gamma ray detector and transmission type neutron flux monitor. Results of the measurements confirmed the validity. With this relation, the GAMMA sub(n)/GAMMA or GAMMA sub(γ)/GAMMA value can be obtained from the measured P sub(CO), and also the level spins be determined by combining the transmission data. Because of the definition of P sub(CO), determination of the resonance parameters is not sensitive to the sample thickness as far as it is sufficiently thick. (auth.)

Inelastic neutron scattering in the spin wave energy gap of the polydomain γ-Mn(12%Ge) alloy

International Nuclear Information System (INIS)

Jankowska-Kisielinska, J.; Mikke, K.

1999-01-01

The subject of the present experiment was the investigation of the inelastic neutron scattering (INS) for energy transfers lower than and close to the energy gap of the spin wave spectrum for long wavelengths. The aim was a search for the excitations at the magnetic Brillouin zone (MBZ) boundary in polydomain Mn(12%Ge) alloy. The present measurements were performed by a 3-axis spectrometer at Maria Reactor at IEA in Swierk. We observed the INS in the polydomain Mn(12%Ge) alloy for energies smaller than and close to the energy gap value of the spin wave spectrum at room temperature. The observed intensity can be treated as a sum of intensity of neutrons scattered on spin waves around magnetic Brillouin zone centre and that of neutrons scattered on fluctuations at the zone boundary. The intensity of both components for energies 2-6 MeV was found to be of the same order. For higher energies spin waves around magnetic zone centre dominate. (author)

Study of the giant multipole resonances especially of the isoscalar giant E2 resonance in 208Pb by medium and high energy resolution inelastic electron scattering

International Nuclear Information System (INIS)

Kuehner, G.

1982-01-01

In the nucleus 208 Pb giant multipole resonances up to excitation energies of Esub(x) = 35 MeV were looked for by medium resolution inelastic electron scattering. Twelve spectra were taken up at incident energies of E 0 = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. On the base of this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forward angles a further weak excitation at Esub(x) approx.= 14.6 MeV appears which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is observed also in (α, α') experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also a Jsup(π) = 3 - character but has to be partly assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gets because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

Electron dynamics in the core-excited CS2 molecule revealed through resonant inelastic x-ray scattering spectroscopy

International Nuclear Information System (INIS)

Marchenko, T; Carniato, S; Journel, L; Guillemin, R; Kawerk, E; Simon, M; Žitnik, M; Kavčič, M; Bučar, K; Bohinc, R; Petric, M; Da Cruz, V Vaz; Gel'mukhanov, F

2015-01-01

We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the CS 2 molecule near the S 1s edge. We show that localization of the S 1s core-hole occurs in CS 2 during the RIXS process due to the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Strong evolution of the RIXS profile with the excitation energy far below the first absorption resonance reflects the onset of electron dynamics triggered by a coherent excitation of multiple electronic states. (paper)

Connections between molecular photoionization and electron-molecule scattering with emphasis on shape resonances

International Nuclear Information System (INIS)

Dehmer, J.L.; Dill, D.

1979-01-01

Most of our detailed information on the spectroscopy and dynamics of the electronic continuum of molecules is based on the complementary probes - photoionization and electron scattering. Though usually studied separately, it is most useful to appreciate the connections between these two processes since our understanding of one is often the key to interpreting or even generating new results in the other. We approach this subject in two steps. First, we very briefly outline the well-established connections, e.g., the Bethe-Born theory and comparisons of isoelectronic systems. Then we focus on a point of contact - the role of shape resonances in molecular photoionization and electron-molecule scattering - for which a substantial amount of new information has become available. Specific topics include mapping of resonances from the neutral (hν + molecule) to the negative ion (e + molecule) system, angular distributions, and interaction with vibration

Influence of six-quark bags on the NN interaction in a resonating group scattering calculation

International Nuclear Information System (INIS)

Zhang Zongye; Braeuer, K.; Faessler, A.; Shimizu, K.

1985-01-01

The influence of six-quark bags oin the nucleon-nucleon (NN) interaction is studied in a dynamical calculation of the NN scattering process. The NN interaction is described by the exchange of gluons and pions between quarks and a phenomenological sigma-meson exchange between nucleons. The quark wave functions are harmonic oscillators and the relative wave function between the two nucleons is determined by the resonating group method. At short distances the NN system is allowed to fuse to a six-quark bag where all six quarks are in a ground state or where two quarks are in excited Op states. The sizes of these six-quark bags are dynamical parameters in the resonating group calculation allowing for spatial polarisation effects during the interaction. The S-wave NN scattering data can be reproduced by adjusting the sigma-coupling strength. The main result is that the six-quark bags with an increased radius have a large influence on the NN scattering process. (orig.)

Investigation on phase noise of the signal from a singly resonant optical parametric oscillator

Science.gov (United States)

Jinxia, Feng; Yuanji, Li; Kuanshou, Zhang

2018-04-01

The phase noise of the signal from a singly resonant optical parametric oscillator (SRO) is investigated theoretically and experimentally. An SRO based on periodically poled lithium niobate is built up that generates the signal with a maximum power of 5.2 W at 1.5 µm. The intensity noise of the signal reaches the shot noise level for frequencies above 5 MHz. The phase noise of the signal oscillates depending on the analysis frequency, and there are phase noise peaks above the shot noise level at the peak frequencies. To explain the phase noise feature of the signal, a semi-classical theoretical model of SROs including the guided acoustic wave Brillouin scattering effect within the nonlinear crystal is developed. The theoretical predictions are in good agreement with the experimental results.

Study on the Interaction between Cadmium Sulphide Nanoparticles and Proteins by Resonance Rayleigh Scattering Spectra

Directory of Open Access Journals (Sweden)

Weiwei Zhu

2013-01-01

Full Text Available The interaction of cadmium sulphide nanoparticles [(CdSn] with proteins has been studied by resonance Rayleigh scattering spectra (RRS. Below the isoelectric point, proteins such as bovine serum albumin (BSA, human serum albumin (HSA, lysozyme (Lys, hemoglobin (HGB, and ovalbumin (OVA can bind with CdSn to form macromolecules by virtue of electrostatic attraction and hydrophobic force. It can result in the enhancement of resonance Rayleigh scattering spectra (RRS intensity. Their maximum scattering peaks were 280 nm, and there was a smaller peak at 370 nm. The scattering enhancement (ΔIRRS is directly proportional to the concentration of proteins. A new RRS method for the determination of trace proteins using uncapped CdSn nanoparticles probe has been developed. The detection limits are 19.6 ng/mL for HSA, 16.7 ng/mL for BSA, 18.5 ng/mL for OVA, 80.2 ng/mL for HGB, and 67.4 ng/mL for Lys, separately. In this work, the optimum condition of reaction, the effect of foreign, and the analytical application had been investigated.

Multi-wavelength Brillouin Raman erbium-doped fiber laser generation in a linear cavity

International Nuclear Information System (INIS)

Shirazi, M R; Harun, S W; Ahmad, H

2014-01-01

A multi-wavelength Brillouin Raman erbium-doped fiber laser is proposed and demonstrated. The setup uses a 7.7 km dispersion compensating fiber simultaneously as the Brillouin and Raman nonlinear gain media and operates in conjunction with a 3 m erbium-doped fiber as the linear gain medium. At a Brillouin pump (BP) wavelength of 1530 nm, where Raman and erbium gains overlap each other, 34 Brillouin Stokes lines having line spacing of 0.075 nm are created by using a Raman pump power of only 24.1 dBm, an erbium pump power of about 22.1 dBm, and a BP power of 6.5 dBm in the proposed linear cavity. The system is highly efficient and is able to generate many comparable peak-power lines at a low pump power. (paper)

Resonant cyclotron scattering in pulsar magnetospheres and its application to isolated neutron stars

International Nuclear Information System (INIS)

Tong Hao; Peng Qiuhe; Xu, Ren-Xin; Song Liming

2010-01-01

Resonant cyclotron scattering (RCS) in pulsar magnetospheres is considered. The photon diffusion equation (Kompaneets equation) for RCS is derived. The photon system is modeled three dimensionally. Numerical calculations show that there exist not only up scattering but also down scattering of RCS, depending on the parameter space. RCS's possible applications to spectral energy distributions of magnetar candidates and radio quiet isolated neutron stars (INSs) are pointed out. The optical/UV excess of INSs may be caused by the down scattering of RCS. The calculations for RX J1856.5-3754 and RX J0720.4-3125 are presented and compared with their observational data. In our model, the INSs are proposed to be normal neutron stars, although the quark star hypothesis is still possible. The low pulsation amplitude of INSs is a natural consequence in the RCS model. (letters)

Quasiresonant scattering

International Nuclear Information System (INIS)

Hategan, Cornel; Comisel, Horia; Ionescu, Remus A.

2004-01-01

The quasiresonant scattering consists from a single channel resonance coupled by direct interaction transitions to some competing reaction channels. A description of quasiresonant Scattering, in terms of generalized reduced K-, R- and S- Matrix, is developed in this work. The quasiresonance's decay width is, due to channels coupling, smaller than the width of the ancestral single channel resonance (resonance's direct compression). (author)

Validity of the independent-processes approximation for resonance structures in electron-ion scattering cross sections

International Nuclear Information System (INIS)

Badnell, N.R.; Pindzola, M.S.; Griffin, D.C.

1991-01-01

The total inelastic cross section for electron-ion scattering may be found in the independent-processes approximation by adding the resonant cross section to the nonresonant background cross section. We study the validity of this approximation for electron excitation of multiply charged ions. The resonant-excitation cross section is calculated independently using distorted waves for various Li-like and Na-like ions using (N+1)-electron atomic-structure methods previously developed for the calculation of dielectronic-recombination cross sections. To check the effects of interference between the two scattering processes, we also carry out detailed close-coupling calculations for the same atomic ions using the R-matrix method. For low ionization stages, interference effects manifest themselves sometimes as strong window features in the close-coupling cross section, which are not present in the independent-processes cross section. For higher ionization stages, however, the resonance features found in the independent-processes approximation are found to be in good agreement with the close-coupling results

Spectral statistics and scattering resonances of complex primes arrays

Science.gov (United States)

Wang, Ren; Pinheiro, Felipe A.; Dal Negro, Luca

2018-01-01

We introduce a class of aperiodic arrays of electric dipoles generated from the distribution of prime numbers in complex quadratic fields (Eisenstein and Gaussian primes) as well as quaternion primes (Hurwitz and Lifschitz primes), and study the nature of their scattering resonances using the vectorial Green's matrix method. In these systems we demonstrate several distinctive spectral properties, such as the absence of level repulsion in the strongly scattering regime, critical statistics of level spacings, and the existence of critical modes, which are extended fractal modes with long lifetimes not supported by either random or periodic systems. Moreover, we show that one can predict important physical properties, such as the existence spectral gaps, by analyzing the eigenvalue distribution of the Green's matrix of the arrays in the complex plane. Our results unveil the importance of aperiodic correlations in prime number arrays for the engineering of gapped photonic media that support far richer mode localization and spectral properties compared to usual periodic and random media.

Resonant Inelastic X-ray Scattering: From band mapping to inter-orbital excitations

International Nuclear Information System (INIS)

Luning, J.; Hague, C.F.

2008-01-01

Resonant inelastic X-ray scattering (also known as resonant X-ray Raman spectroscopy when only valence and conduction states are involved in the final state excitation) has developed into a major tool for understanding the electronic properties of complex materials. Presently it provides access to electron excitations in the few hundred meV range with element and bulk selectivity. Recent progress in X-ray optics and synchrotron radiation engineering have opened up new perspectives for this powerful technique to improve resolving power and efficiency. We briefly present the basics of the method and illustrate its potential with examples chosen from the literature. (authors)

Nuclear resonant scattering of synchrotron radiation from nuclei in the Brownian motion

International Nuclear Information System (INIS)

Razdan, Ashok

2003-01-01

The time evolution of the coherent forward scattering of the synchrotron radiation for resonant nuclei in Brownian motion is studied. Apart from target thickness, the appearance of the dynamical beats also depends on 'α' which is the ratio of the harmonic force constant to the damping force constant of harmonic oscillator undergoing Brownian motion

Tetraquark resonances computed with static lattice QCD potentials and scattering theory

Directory of Open Access Journals (Sweden)

Bicudo Pedro

2018-01-01

Full Text Available We study tetraquark resonances with lattice QCD potentials computed for two static quarks and two dynamical quarks, the Born-Oppenheimer approximation and the emergent wave method of scattering theory. As a proof of concept we focus on systems with isospin I = 0, but consider different relative angular momenta l of the heavy b quarks. We compute the phase shifts and search for S and T matrix poles in the second Riemann sheet. We predict a new tetraquark resonance for l = 1, decaying into two B mesons, with quantum numbers I(JP = 0(1−, mass m=10576−4+4 MeV and decay width Γ=112−103+90 MeV.

Dynamics of ponderomotive self-focusing and periodic bursts of stimulated Brillouin backscattering in plasmas

International Nuclear Information System (INIS)

Andreev, N.E.; Gorbunov, L.M.; Tarakanov, S.V.; Zykov, A.I.

1993-01-01

The space--time evolution of ponderomotive self-focusing of electromagnetic beams in a plasma is investigated. The quasineutral, hydrodynamic plasma response to the ponderomotive force is considered. The set of coupled quasioptic and acoustic equations is solved both analytically and numerically for slab and cylindrical beams. It is shown that the transient process of self-focusing has the form of a nonlinear wave propagating along the beam axis from boundary into the interior of a plasma with velocity considerably higher than the ion-sound velocity. Mutual dynamics of self-focusing and stimulated Brillouin backscattering (SBBS) is computed. It is shown that self-focusing results in the high intensity periodical bursts of SBBS. However, the time average level of scattered radiation is quite low

Modes of spheroidal ion plasmas at the Brillouin limit

International Nuclear Information System (INIS)

Tinkle, M. D.; Greaves, R. G.; Surko, C. M.

1995-01-01

Brillouin-density pure ion plasmas have been generated in a quadrupole Penning tray by electron-beam ionization of a low-pressure gas. Large, spheroidal, steady-state plasmas are produced that extend to one of the trap electrodes. With the density fixed at the Brillouin limit by the high ion production rate, the electrode potentials determine the plasma shape. The frequencies of azimuthally propagating cyclotron and diocotron modes are found to vary significantly with the plasma aspect ratio. For oblate plasmas, we are able to test theoretical predictions of a simple fluid model, and the frequencies are in good agreement

One phonon resonant Raman scattering in semiconductor quantum wires: Magnetic field effect

Energy Technology Data Exchange (ETDEWEB)

Betancourt-Riera, Re., E-mail: rbriera@posgrado.cifus.uson.mx [Instituto Tecnologico de Hermosillo, Avenida Tecnologico S/N, Colonia Sahuaro, C.P. 83170, Hermosillo, Sonor, (Mexico); Departamento de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088, C.P. 83190, Hermosillo, Sonora (Mexico); Betancourt-Riera, Ri. [Instituto Tecnologico de Hermosillo, Avenida Tecnologico S/N, Colonia Sahuaro, C.P. 83170, Hermosillo, Sonora (Mexico); Nieto Jalil, J.M. [Tecnologico de Monterrey-Campus Sonora Norte, Bulevar Enrique Mazon Lopez No. 965, C.P. 83000, Hermosillo, Sonora (Mexico); Riera, R. [Departamento de Investigacion en Fisica, Universidad de Sonora, Apartado Postal 5-088, C.P. 83190, Hermosillo, Sonora (Mexico)

2013-02-01

We have developed a theory of one phonon resonant Raman scattering in a semiconductor quantum wire of cylindrical geometry in the presence of an external magnetic field distribution, parallel to the cylinder axis. The effect of the magnetic field in the electron and hole states, and in the Raman scattering efficiency, is determinate. We consider the electron-phonon interaction using a Froehlich-type Hamiltonian, deduced for the case of complete confinement phonon modes by Comas and his collaborators. We also assume T=0 K, a single parabolic conduction and valence bands. The spectra are discussed for different magnetic field values and the selection rules for the processes are also studied.

Study of a non-ideal liquid mixture in the hydrodynamic regime. Rayleigh-Brillouin spectra, sound propagation and damping in the CH3CN-CCl4 system at the azeotropic composition

International Nuclear Information System (INIS)

Sassi, Paola; D'Elia, Valerio; Cataliotti, Rosario Sergio

2003-01-01

The hydrodynamic behaviour in the GHz frequency region has been analzsed for the non-ideal CH 3 CN-CCl 4 liquid mixture around the azeotropic composition. Rayleigh-Brillouin spectra have been measured as a function of temperature and composition, at fixed value of transferred wave vector in the 90 deg. scattering geometry, and also at different scattering angles to study dispersion with frequency of the spectral observables. These measurements have been complemented by those of refractive index, density and viscosity at the same temperatures and mole fraction values. Very interesting behaviour of the classic Brillouin spectral observables, such as the hypersonic propagation speeds and the acoustic absorption coefficients, has been revealed near the azeotropic composition of the mixture at the investigated temperatures, namely 15 deg. C, 25 deg. C, 40 deg. C and 60 deg. C. These effects have been interpreted at the light of the Mountain and Deutch theory of binary solutions and the forecast behaviour of the intermolecular forces around the azeotropic point composition of these very different molecular liquids

Ultrafast spectral interferometry of resonant secondary emission from quantum wells: From Rayleigh scattering to coherent emission from biexcitons

DEFF Research Database (Denmark)

Birkedal, Dan; Shah, Jagdeep; Pfeiffer, L. N.

1999-01-01

Recent investigations of secondary emission from quantum well excitons following ultrafast resonant excitation have demonstrated an intricate interplay of coherent Rayleigh scattering and incoherent luminescence. We have very recently demonstrated that it is possible to isolate and time resolve...... the coherent field associated with Rayleigh component using ultrafast spectral interferometry or Tadpole, thus, obtaining substantial and new information of the nature of resonant secondary emission. Our observation demonstrates that Rayleigh scattering from static disorder is inherently a non-ergodic process...... invalidating the use of current theories using ensemble averages to describe our observations. Furthermore, we report here a new and hitherto unknown coherent scattering mechanism involving the two-photon coherence associated with the biexciton transition. The process leaves an exciton behind taking up...

Bi-Directional Brillouin Optical Time Domain Analyzer System for Long Range Distributed Sensing

Science.gov (United States)

Guo, Nan; Wang, Liang; Wang, Jie; Jin, Chao; Tam, Hwa-Yaw; Zhang, A. Ping; Lu, Chao

2016-01-01

We propose and experimentally demonstrate a novel scheme of bi-directional Brillouin time domain analyzer (BD-BOTDA) to extend the sensing range. By deploying two pump-probe pairs at two different wavelengths, the Brillouin frequency shift (BFS) distribution over each half of the whole fiber can be obtained with the simultaneous detection of Brillouin signals in both channels. Compared to the conventional unidirectional BOTDA system of the same sensing range, the proposed BD-BOTDA scheme enables distributed sensing with a performance level comparable to the conventional one with half of the sensing range and a spatial resolution of 2 m, while maintaining the Brillouin signal-to-noise ratio (SNR) and the BFS uncertainty. Based on this technique, we have achieved distributed temperature sensing with a measurement range of 81.9 km fiber at a spatial resolution of 2 m and BFS uncertainty of ~0.44 MHz without introducing any complicated components or schemes. PMID:27999250

Bi-Directional Brillouin Optical Time Domain Analyzer System for Long Range Distributed Sensing.

Science.gov (United States)

Guo, Nan; Wang, Liang; Wang, Jie; Jin, Chao; Tam, Hwa-Yaw; Zhang, A Ping; Lu, Chao

2016-12-16

We propose and experimentally demonstrate a novel scheme of bi-directional Brillouin time domain analyzer (BD-BOTDA) to extend the sensing range. By deploying two pump-probe pairs at two different wavelengths, the Brillouin frequency shift (BFS) distribution over each half of the whole fiber can be obtained with the simultaneous detection of Brillouin signals in both channels. Compared to the conventional unidirectional BOTDA system of the same sensing range, the proposed BD-BOTDA scheme enables distributed sensing with a performance level comparable to the conventional one with half of the sensing range and a spatial resolution of 2 m, while maintaining the Brillouin signal-to-noise ratio (SNR) and the BFS uncertainty. Based on this technique, we have achieved distributed temperature sensing with a measurement range of 81.9 km fiber at a spatial resolution of 2 m and BFS uncertainty of ~0.44 MHz without introducing any complicated components or schemes.

Surface-Enhanced Raman Scattering Using Silica Whispering-Gallery Mode Resonators

Science.gov (United States)

Anderson, Mark S.

2013-01-01

The motivation of this work was to have robust spectroscopic sensors for sensitive detection and chemical analysis of organic and molecular compounds. The solution is to use silica sphere optical resonators to provide surface-enhanced spectroscopic signal. Whispering-gallery mode (WGM) resonators made from silica microspheres were used for surface-enhanced Raman scattering (SERS) without coupling to a plasmonic mechanism. Large Raman signal enhancement is observed by exclusively using 5.08-micron silica spheres with 785-nm laser excitation. The advantage of this non-plasmonic approach is that the active substrate is chemically inert silica, thermally stable, and relatively simple to fabricate. The Raman signal enhancement is broadly applicable to a wide range of molecular functional groups including aliphatic hydrocarbons, siloxanes, and esters. Applications include trace organic analysis, particularly for in situ planetary instruments that require robust sensors with consistent response.

Alpha clustering in Ti isotopes: 40,44,48Ca + α resonant scattering

Directory of Open Access Journals (Sweden)

Bailey Sam

2016-01-01

Full Text Available Measurements were made of the 4He(40,44,48Ca,α resonant scattering reactions at 180° and up to Ec.m. ~ 11.5MeV, using the Thick Target Inverse Kinematics technique. These measurements are discussed, with a focus on assessing their usefulness for investigating α-clustering in medium mass 44,48,52Ti nuclei.

Iota-dependent resonance absorption in the optical model description of alpha particle elastic scattering

International Nuclear Information System (INIS)

Chyla, K.; Jarczyk, L.; Maciuk, B.; Zipper, W.

1976-01-01

Alpha particle scattering from 28 Si has been studied at five bombarding energies from 23.5 to 28.5 MeV. iota-dependent resonance absorption has been introduced to the optical model analysis of 28 Si (α,β) 28 Si reaction. (author)

Brillouin Optical Correlation Domain Analysis in Composite Material Beams.

Science.gov (United States)

Stern, Yonatan; London, Yosef; Preter, Eyal; Antman, Yair; Diamandi, Hilel Hagai; Silbiger, Maayan; Adler, Gadi; Levenberg, Eyal; Shalev, Doron; Zadok, Avi

2017-10-02

Structural health monitoring is a critical requirement in many composites. Numerous monitoring strategies rely on measurements of temperature or strain (or both), however these are often restricted to point-sensing or to the coverage of small areas. Spatially-continuous data can be obtained with optical fiber sensors. In this work, we report high-resolution distributed Brillouin sensing over standard fibers that are embedded in composite structures. A phase-coded, Brillouin optical correlation domain analysis (B-OCDA) protocol was employed, with spatial resolution of 2 cm and sensitivity of 1 °K or 20 micro-strain. A portable measurement setup was designed and assembled on the premises of a composite structures manufacturer. The setup was successfully utilized in several structural health monitoring scenarios: (a) monitoring the production and curing of a composite beam over 60 h; (b) estimating the stiffness and Young's modulus of a composite beam; and (c) distributed strain measurements across the surfaces of a model wing of an unmanned aerial vehicle. The measurements are supported by the predictions of structural analysis calculations. The results illustrate the potential added values of high-resolution, distributed Brillouin sensing in the structural health monitoring of composites.

Brillouin Optical Correlation Domain Analysis in Composite Material Beams

Directory of Open Access Journals (Sweden)

Yonatan Stern

2017-10-01

Full Text Available Structural health monitoring is a critical requirement in many composites. Numerous monitoring strategies rely on measurements of temperature or strain (or both, however these are often restricted to point-sensing or to the coverage of small areas. Spatially-continuous data can be obtained with optical fiber sensors. In this work, we report high-resolution distributed Brillouin sensing over standard fibers that are embedded in composite structures. A phase-coded, Brillouin optical correlation domain analysis (B-OCDA protocol was employed, with spatial resolution of 2 cm and sensitivity of 1 °K or 20 micro-strain. A portable measurement setup was designed and assembled on the premises of a composite structures manufacturer. The setup was successfully utilized in several structural health monitoring scenarios: (a monitoring the production and curing of a composite beam over 60 h; (b estimating the stiffness and Young’s modulus of a composite beam; and (c distributed strain measurements across the surfaces of a model wing of an unmanned aerial vehicle. The measurements are supported by the predictions of structural analysis calculations. The results illustrate the potential added values of high-resolution, distributed Brillouin sensing in the structural health monitoring of composites.

Resonances and background: A decomposition of scattering information

International Nuclear Information System (INIS)

Engdahl, E.; Braendas, E.; Rittby, M.; Elander, N.

1988-01-01

An analytic representation of the full Green's function including bound states, resonances, and remaining contributions has been obtained for a class of dilatation analytic potentials, including the superimposed Coulomb potential. It is demonstrated how to obtain the locations and residues of the poles of the Green's function as well as the associated generalized spectral density. For a model potential which has a barrier and decreases exponentially at infinity we have found a certain deflation property of the generalized spectral density. A qualitative explanation of this phenomenon is suggested. This constitutes the motivation for an approximation that explicitly shows a decomposition of the (real) continuum, corresponding to scattering data, into resonances and background contributions. The present representation is also shown to incorporate the appropriate pole-background interferences. Numerical residue strings are computed and analyzed. Results for the Coulomb potential plus the above-mentioned model potential are reported and compared with the previous non-Coulomb case. A similar deflation effect is seen to occur, as well as basically the same pole- and residue-string behavior. The relevance of the present analysis in relation to recently planned experiments with electron-cooled beams of highly charged ions is briefly discussed

Modes of spheroidal ion plasmas at the Brillouin limit

International Nuclear Information System (INIS)

Tinkle, M.D.; Greaves, R.G.; Surko, C.M.

1996-01-01

The confinement properties and collective modes of single-component plasmas are investigated in a quadrupole Penning trap. Brillouin-density pure ion plasmas are generated by electron-beam ionization of a low-pressure gas. Large, spheroidal, steady-state plasmas are produced, extending out to contact one or more of the trap electrodes. With the density fixed at the Brillouin limit by the high ion production rate, the electrode potentials determine the plasma shape. The frequencies of azimuthally propagating cyclotron and diocotron modes are found to vary significantly with the plasma aspect ratio. For oblate plasmas, the frequencies are in good agreement with a simple fluid model. copyright 1996 American Institute of Physics

Resonant two-magnon Raman scattering in parent compounds of high-Tc superconductors

International Nuclear Information System (INIS)

Chubukov, A.V.; Frenkel, D.M.

1995-01-01

We propose a theory of two-magnon Raman scattering from the insulating parent compounds of high-T c superconductors, which contains information not only on magnetism, but also on the electronic properties in these materials. We use spin-density-wave formalism for the Hubbard model, and study diagrammatically the profile of the two-magnon scattering and its intensity dependence on the incoming photon frequency ω i both for ω i much-lt U and in the resonant regime, in which the energy of the incident photon is close to the gap between conduction and valence bands. In the nonresonant case, we identify the diagrams which contribute to the conventional Loudon-Fleury Hamiltonian. In the resonant regime, where most of the experiments have been done, we find that the dominant contribution to Raman intensity comes from a different diagram, one which allows for a simultaneous vanishing of all three of its dominators (i.e., a triple resonanc). We study this diagram in detail and show taht the triple resonance, combined with the spin-density-wave dispersion relation for the carriers, explains the unusual features found in the two-magnon profile and in the two-magnon peak intensity dependence on the incoming photon frequency. In particular, our theory predicts a maximum of the two-magnon peak intensity right at the upper edge of the features in the optical data, which has been one of the key experimental puzzles

Confluent Heun functions and the physics of black holes: Resonant frequencies, Hawking radiation and scattering of scalar waves

Energy Technology Data Exchange (ETDEWEB)

Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)

2016-10-15

We apply the confluent Heun functions to study the resonant frequencies (quasispectrum), the Hawking radiation and the scattering process of scalar waves, in a class of spacetimes, namely, the ones generated by a Kerr–Newman–Kasuya spacetime (dyon black hole) and a Reissner–Nordström black hole surrounded by a magnetic field (Ernst spacetime). In both spacetimes, the solutions for the angular and radial parts of the corresponding Klein–Gordon equations are obtained exactly, for massive and massless fields, respectively. The special cases of Kerr and Schwarzschild black holes are analyzed and the solutions obtained, as well as in the case of a Schwarzschild black hole surrounded by a magnetic field. In all these special situations, the resonant frequencies, Hawking radiation and scattering are studied. - Highlights: • Charged massive scalar field in the dyon black hole and massless scalar field in the Ernst spacetime are analyzed. • The confluent Heun functions are applied to obtain the solution of the Klein–Gordon equation. • The resonant frequencies are obtained. • The Hawking radiation and the scattering process of scalar waves are examined.

The magnetic order of GdMn₂Ge₂ studied by neutron diffraction and x-ray resonant magnetic scattering.

Science.gov (United States)

Granovsky, S A; Kreyssig, A; Doerr, M; Ritter, C; Dudzik, E; Feyerherm, R; Canfield, P C; Loewenhaupt, M

2010-06-09

The magnetic structure of GdMn₂Ge₂ (tetragonal I4/mmm) has been studied by hot neutron powder diffraction and x-ray resonant magnetic scattering techniques. These measurements, along with the results of bulk experiments, confirm the collinear ferrimagnetic structure with moment direction parallel to the c-axis below T(C) = 96 K and the collinear antiferromagnetic phase in the temperature region T(C) < T < T(N) = 365 K. In the antiferromagnetic phase, x-ray resonant magnetic scattering has been detected at Mn K and Gd L₂ absorption edges. The Gd contribution is a result of an induced Gd 5d electron polarization caused by the antiferromagnetic order of Mn-moments.

Magnetization pinning in conducting films demonstrated using broadband ferromagnetic resonance

Science.gov (United States)

Kostylev, M.; Stashkevich, A. A.; Adeyeye, A. O.; Shakespeare, C.; Kostylev, N.; Ross, N.; Kennewell, K.; Magaraggia, R.; Roussigné, Y.; Stamps, R. L.

2010-11-01

The broadband microstrip ferromagnetic resonance (FMR), cavity FMR, and Brillouin light scattering spectroscopy techniques have been applied for detection and characterization of a magnetic inhomogeneity in a film sample. In the case of a 100 nm thick permalloy film, an additional magnetically depleted top sublayer has been detected due to pinning effect it produces on the magnetization in the bulk of the film. The pinning results in appearance of an exchange standing spin wave mode in the broadband FMR absorption spectrum, whose amplitudes are different depending on whether the film or the film substrate faces the microstrip transducer. Comparison of the experimental amplitudes for this mode with results of our theory for both film placements revealed that the depleted layer is located at the film surface facing away from the film substrate. Subsequent broadband FMR characterization of a large number of other presumably single-layer films with thicknesses in the range 30-100 nm showed the same result.

Quasi-particle interference of heavy fermions in resonant x-ray scattering.

Science.gov (United States)

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

2016-10-01

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 Ce M In 5 ( M = Co, Rh). Temperature- and doping-dependent RXS measurements at the Ce- M 4 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.

Elastic and Raman scattering of photons from the giant dipole resonance

International Nuclear Information System (INIS)

Bar-Noy, T.

1978-12-01

In the present work we investigated nuclear Raman and elastic scattering of photons from the Giant Dipole Resonance (GDR) of medium and heavy nuclei. The photons beams were obtained from thermal neutron capture on V, Fe, Ni, Cu and Cr discs, utilizing the IRR-2 reactor. Nine targets, 159 Tb, 165 Ho, 175 Lu, 181 Ta, 197 Au, 209 Bi, 232 Th, 237 Np, and 238 U, representing all spherical and deformed nuclei in the region of medium and heavy nuclei, were used. As preliminary works, we discovered and investigated the 11.4 MeV γ-line, measured the attenuation coefficients at 9 and 11.4 MeV, performed a numerical calculation of Delbrueck amplitudes and modified the Simple Rotator Model (SRM). The absolute scattering cross-sections were measured for each scatterer at 4-8 different energies, and angular distributions in the range 90 deg to 140 deg were carried out at 9 MeV and 11.4 MeV. The experimental results were compared with theoretical predictions of the modified SRM and the Dynamic Collective Model (DCM). The results proved that the modified SRM describes appropriately the scattering from the GDR, including elastic and Raman absolute cross-sections and their angular distributions. (author)

The effect of signal to noise ratio on accuracy of temperature measurements for Brillouin lidar in water

Science.gov (United States)

Liang, Kun; Niu, Qunjie; Wu, Xiangkui; Xu, Jiaqi; Peng, Li; Zhou, Bo

2017-09-01

A lidar system with Fabry-Pérot etalon and an intensified charge coupled device can be used to obtain the scattering spectrum of the ocean and retrieve oceanic temperature profiles. However, the spectrum would be polluted by noise and result in a measurement error. To analyze the effect of signal to noise ratio (SNR) on the accuracy of measurements for Brillouin lidar in water, the theory model and characteristics of SNR are researched. The noise spectrums with different SNR are repetitiously measured based on simulation and experiment. The results show that accuracy is related to SNR, and considering the balance of time consumption and quality, the average of five measurements is adapted for real remote sensing under the pulse laser conditions of wavelength 532 nm, pulse energy 650 mJ, repetition rate 10 Hz, pulse width 8 ns and linewidth 0.003 cm-1 (90 MHz). Measuring with the Brillouin linewidth has a better accuracy at a lower temperature (15 °C), based on the classical retrieval model we adopt. The experimental results show that the temperature error is 0.71 °C and 0.06 °C based on shift and linewidth respectively when the image SNR is at the range of 3.2 dB-3.9 dB.

Spin-flip measurements in the proton inelastic scattering on 12C and giant resonance effects

International Nuclear Information System (INIS)

De Leo, R.; D'Erasmo, G.; Ferrero, F.; Pantaleo, A.; Pignanelli, M.

1975-01-01

Differential cross sections and spin-flip probabilities (SFP) for the inelastic scattering of protons, exciting the 2 + state at 4.43 MeV in 12 C, have been measured at several incident energies between 15.9 and 37.6 MeV. The changes in the shape of the SFP angular distributions are rather limited, while the absolute values show a pronounced increase, resonant like, in two energy regions centered at about 20 and 29 MeV. The second resonance reproduces very closely the energy dependence of the E2 giant quadrupole strength found in a previous experiment. The resonance at 20 MeV should correspond to a substructure of the E1 giant dipole resonance. (Auth.)

Generalized theory of resonance excitation by sound scattering from an elastic spherical shell in a nonviscous fluid.

Science.gov (United States)

Mitri, Farid G

2012-08-01

This work presents the general theory of resonance scattering (GTRS) by an elastic spherical shell immersed in a nonviscous fluid and placed arbitrarily in an acoustic beam. The GTRS formulation is valid for a spherical shell of any size and material regardless of its location relative to the incident beam. It is shown here that the scattering coefficients derived for a spherical shell immersed in water and placed in an arbitrary beam equal those obtained for plane wave incidence. Numerical examples for an elastic shell placed in the field of acoustical Bessel beams of different types, namely, a zero-order Bessel beam and first-order Bessel vortex and trigonometric (nonvortex) beams are provided. The scattered pressure is expressed using a generalized partial-wave series expansion involving the beam-shape coefficients (BSCs), the scattering coefficients of the spherical shell, and the half-cone angle of the beam. The BSCs are evaluated using the numerical discrete spherical harmonics transform (DSHT). The far-field acoustic resonance scattering directivity diagrams are calculated for an albuminoidal shell immersed in water and filled with perfluoropropane gas, by subtracting an appropriate background from the total far-field form function. The properties related to the arbitrary scattering are analyzed and discussed. The results are of particular importance in acoustical scattering applications involving imaging and beam-forming for transducer design. Moreover, the GTRS method can be applied to investigate the scattering of any beam of arbitrary shape that satisfies the source-free Helmholtz equation, and the method can be readily adapted to viscoelastic spherical shells or spheres.

Resonances in a two-dimensional electron waveguide with a single δ-function scatterer

International Nuclear Information System (INIS)

Boese, Daniel; Lischka, Markus; Reichl, L. E.

2000-01-01

We study the conductance properties of a straight two-dimensional electron waveguide with an s-like scatterer modeled by a single δ-function potential with a finite number of modes. Even such a simple system exhibits interesting resonance phenomena. These resonances are explained in terms of quasibound states both by using a direct solution of the Schroedinger equation and by studying the Green's function of the system. Using the Green's function we calculate the survival probability as well as the power absorption, and show the influence of the quasibound states on these two quantities. (c) 2000 The American Physical Society

Modern Theory of Gratings Resonant Scattering: Analysis Techniques and Phenomena

CERN Document Server

Sirenko, Yuriy K

2010-01-01

Diffraction gratings are one of the most popular objects of analysis in electromagnetic theory. The requirements of applied optics and microwave engineering lead to many new problems and challenges for the theory of diffraction gratings, which force us to search for new methods and tools for their resolution. In Modern Theory of Gratings, the authors present results of the electromagnetic theory of diffraction gratings that will constitute the base of further development of this theory, which meet the challenges provided by modern requirements of fundamental and applied science. This volume covers: spectral theory of gratings (Chapter 1) giving reliable grounds for physical analysis of space-frequency and space-time transformations of the electromagnetic field in open periodic resonators and waveguides; authentic analytic regularization procedures (Chapter 2) that, in contradistinction to the traditional frequency-domain approaches, fit perfectly for the analysis of resonant wave scattering processes; paramet...

Investigation of silicon width (p, p') resonance scattering in left angle 110 right angle channeling direction

International Nuclear Information System (INIS)

Ditroi, F.; Meyer, J.D.; Michelmann, R.; Kislat, D.; Bethge, K.

1994-01-01

Crystalline silicon samples were investigated both in channeling and random directions by using the (p, p') resonance scattering at 2.3 MeV bombarding energy. The samples were positioned in the scattering chamber of a VdG accelerator after 2 m collimating path. The peaks due to the resonance at 2.1 MeV were measured at different angles in the vicinity of the channeling and random directions. A peak shift and broadening was seen at the channeling and near channeling directions compared with the random one. The spectra were also simulated using our modified Monte Carlo calculation method for stopping, range and energy distribution in highly ordered materials. The energy shift and the broadening between the random and the channeling spectra were compared and explained. (orig.)

Spin degrees of freedom in electron nucleon scattering in the resonance region

International Nuclear Information System (INIS)

Burkert, V.D.

1987-01-01

Some aspects of using polarized electrons and/or polarized targets in electron-nucleon scattering experiments are discussed. Polarization measurements can be used to extend the knowledge of nucleon form-factor measurements to higher Q 2 and are indispensable for a model-independent extraction of the helicity amplitudes of exclusive meson production. Measurements of polarization asymmetries may also help in revealing the excitation of weaker resonances

Magnetic neutron scattering resonance of high-¤Tc¤ superconductors in external magnetic fields: An SO(5) study

DEFF Research Database (Denmark)

Mortensen, Asger; Rønnow, Henrik Moodysson; Bruus, Henrik

2000-01-01

The magnetic resonance at 41 meV observed in neutron scattering studies of YBa2Cu3O7 holds a key position in the understanding of high-T-c, superconductivity. Within the SO(5) model for superconductivity and antiferromagnetism, we have calculated the effect of an applied magnetic field on the neu......The magnetic resonance at 41 meV observed in neutron scattering studies of YBa2Cu3O7 holds a key position in the understanding of high-T-c, superconductivity. Within the SO(5) model for superconductivity and antiferromagnetism, we have calculated the effect of an applied magnetic field...

151Eu nuclear resonant inelastic scattering of Eu3Pd20Ge6

International Nuclear Information System (INIS)

Tsutsui, S.; Yoda, Y.; Kobayashi, Y.; Higashitaniguchi, S.; Seto, M.; Kitagawa, J.; Takabatake, T.

2010-01-01

151 Eu nuclear resonant inelastic scattering of Eu 3 Pd 20 Ge 6 . The Eu partial phonon density of states (DOS) in Eu 3 Pd 20 Ge 6 are investigated using 151 Eu nuclear resonance inelastic scattering (NRIS). 151 Eu NRIS was carried out at BL09XU of SPring-8. Significant temperature dependence was found in the partial phonon DOS. Judging from the valence change at the Eu 4a site and the comparison with the ab initio calculation of Eu 3 Pd 20 Ge 6 , the change of the Eu DOS is caused by the electronic states. On the other hand, significant acoustic contribution was found even at the guest site of the Eu ones. In addition, slower average velocity than transverse sound velocity was obtained by Eu partial phonon DOS. Considering that heat is carried by the acoustic phonon in materials, the present results demonstrate that the moderate thermal insulation in Eu 3 Pd 20 Ge 6 is connected with the observation of slow average sound velocity at the Eu sites. (K.F.)

Diffuse Surface Scattering in the Plasmonic Resonances of Ultralow Electron Density Nanospheres.

Science.gov (United States)

Monreal, R Carmina; Antosiewicz, Tomasz J; Apell, S Peter

2015-05-21

Localized surface plasmon resonances (LSPRs) have recently been identified in extremely diluted electron systems obtained by doping semiconductor quantum dots. Here, we investigate the role that different surface effects, namely, electronic spill-out and diffuse surface scattering, play in the optical properties of these ultralow electron density nanosystems. Diffuse scattering originates from imperfections or roughness at a microscopic scale on the surface. Using an electromagnetic theory that describes this mechanism in conjunction with a dielectric function including the quantum size effect, we find that the LSPRs show an oscillatory behavior in both position and width for large particles and a strong blue shift in energy and an increased width for smaller radii, consistent with recent experimental results for photodoped ZnO nanocrystals. We thus show that the commonly ignored process of diffuse surface scattering is a more important mechanism affecting the plasmonic properties of ultralow electron density nanoparticles than the spill-out effect.

Quantum Proximity Resonances

International Nuclear Information System (INIS)

Heller, E.J.

1996-01-01

It is well known that at long wavelengths λ an s-wave scatterer can have a scattering cross section σ on the order of λ 2 , much larger than its physical size, as measured by the range of its potential. Very interesting phenomena can arise when two or more identical scatterers are placed close together, well within one wavelength. We show that, for a pair of identical scatterers, an extremely narrow p-wave open-quote open-quote proximity close-quote close-quote resonance develops from a broader s-wave resonance of the individual scatterers. A new s-wave resonance of the pair also appears. The relation of these proximity resonances (so called because they appear when the scatterers are close together) to the Thomas and Efimov effects is discussed. copyright 1996 The American Physical Society

The fusion rate in the transmission resonance model

International Nuclear Information System (INIS)

Jaendel, M.

1992-01-01

Resonant transmission of deuterons through a chain of target deuterons in a metal matrix has been suggested as an explanation for the cold fusion phenomena. In this paper the fusion rate in such transmission resonance models is estimated, and the basic physical constraints are discussed. The dominating contribution to the fusion yield is found to come from metastable states. The fusion rate is well described by the Wentzel-Kramer-Brillouin approximation and appears to be much too small to explain the experimental anomalies

Resonant Soft X-ray Scattering of Cellulose Microstructure in Plant Primary Cell Walls

Science.gov (United States)

Ye, Dan; Kiemle, Sarah N.; Wang, Cheng; Cosgrove, Daniel J.; Gomez, Esther W.; Gomez, Enrique D.

Cellulosic biomass is the most abundant raw material available for the production of renewable and sustainable biofuels. Breaking down cellulose is the rate-limiting step in economical biofuel production; therefore, a detailed understanding of the microscopic structure of plant cell walls is required to develop efficient biofuel conversion methods. Primary cell walls are key determinants of plant growth and mechanics. Their structure is complex and heterogeneous, making it difficult to elucidate how various components such as pectin, hemicellulose, and cellulose contribute to the overall structure. The electron density of these wall components is similar; such that conventional hard X-ray scattering does not generate enough contrast to resolve the different elements of the polysaccharide network. The chemical specificity of resonant soft X-ray scattering allows contrast to be generated based on differences in chemistry of the different polysaccharides. By varying incident X-ray energies, we have achieved increased scattering contrast between cellulose and other polysaccharides from primary cell walls of onions. By performing scattering at certain energies, features of the network structure of the cell wall are resolved. From the soft X-ray scattering results, we obtained the packing distance of cellulose microfibrils embedded in the polysaccharide network.

Low-energy D* + (D-bar)10 scattering and the nature of resonance-like structure Z+(4430)

International Nuclear Information System (INIS)

Gong Ming; Meng Guozhan; He Song; Liu Chuan; Niu Zhiyuan; Shen Yuan; Chen Ying; Li Gang; Zhang Yuanjiang; Liu Yubin; Meng Xiangfei; Ma Jianping; Zhang Jianbo; CLQCD collaboration

2010-01-01

Low-energy scattering of D *+ and (D-bar) 1 0 meson is studied using quenched lattice QCD with improved lattice actions on anisotropic lattices. The threshold scattering parameters, namely the scattering length a 0 and the effective range r 0 , for the s-wave scattering in J P = 0 - channel are extracted: a 0 = 2.52(47) fm and r 0 = 0.7(1) fm. It is argued that, albeit the interaction between the two charmed mesons being attractive, it is unlikely that they can form a shallow bound state in this channel. Our calculation provides some useful information on the nature of the newly discovered resonance-like structure Z + (4430) by the Belle Collaboration. (authors)

Phase transition in lead titanate thin films: a Brillouin study

International Nuclear Information System (INIS)

Kuzel, P; Dugautier, C; Moch, P; Marrec, F Le; Karkut, M G

2002-01-01

The elastic properties of both polycrystalline and epitaxial PbTiO 3 (PTO) thin films are studied using Brillouin scattering spectroscopy. The epitaxial PTO films were prepared by pulsed laser ablation on (1) a [0 0 1] single crystal of SrTiO 3 (STO) doped with Nb and (2) a [0 0 1] STO buffered with a layer of YBa 2 Cu 3 O 7 . The polycrystalline PTO films were prepared by sol-gel on a Si substrate buffered with TiO 2 and Pt layers. The data analysis takes into account the ripple and the elasto-optic contributions. The latter significantly affects the measured spectra since it gives rise to a Love mode in the p-s scattering geometry. At room temperature, the spectra of the epitaxially grown samples are interpreted using previously published elastic constants of PTO single crystals. Sol-gel samples exhibit appreciable softening of the effective elastic properties compared to PTO single crystals: this result is explained by taking into account the random orientation of the microscopic PTO grains. For both the polycrystalline and the epitaxial films we have determined that the piezoelectric terms do not contribute to the spectra. The temperature dependence of the spectra shows strong anomalies of the elastic properties near the ferroelectric phase transition. Compared to the bulk, T C is higher in the sol-gel films, while in the epitaxial films the sign of the T C shift depends on the underlying material

Electron Dynamics in the Core-Excited CS 2 Molecule Revealed through Resonant Inelastic X-Ray Scattering Spectroscopy

OpenAIRE

Marchenko , T; Carniato , S; Journel , L; Guillemin , R; Kawerk , E; Žitnik , M; Kavčič , M; Bučar , K; Bohinc , R; Petric , M; Vaz Da Cruz , V; Gel 'mukhanov , F; Simon , Marielle

2015-01-01

International audience; We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS) in the carbon disulphide CS 2 molecule near the sulfur K-absorption edge. We observe a strong evolution of the RIXS spectral profile with the excitation energy tuned below the lowest unoccupied molecular orbital (LUMO) absorption resonance. The reason for this is twofold. Reducing the photon energy in the vicinity of the LUMO absorption resonance leads to a relative suppressi...

Resonant and kinematical enhancement of He scattering from LiF(001) surface and pseudosurface vibrational normal modes

International Nuclear Information System (INIS)

Nichols, W.L.; Weare, J.H.

1986-01-01

One-phonon cross sections calculated from sagittally polarized vibrational normal modes account for most salient inelastic-scattering intensities seen in He-LiF(001) and measurements published by Brusdeylins, Doak, and Toennies. We have found that most inelastic intensities which cannot be attributed to potential resonances can be explained as kinematically enhanced scattering from both surface and pseudosurface bulk modes

Analysis of Order Formation in Block Copolymer Thin Films UsingResonant Soft X-Ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Virgili, Justin M.; Tao, Yuefei; Kortright, Jeffrey B.; Balsara,Nitash P.; Segalman, Rachel A.

2006-11-27

The lateral order of poly(styrene-block-isoprene) copolymer(PS-b-PI) thin films is characterized by the emerging technique ofresonant soft X-ray scattering (RSOXS) at the carbon K edge and comparedto ordering in bulk samples of the same materials measured usingconventional small-angle X-ray scattering. We show resonance using theoryand experiment that the loss of scattering intensity expected with adecrease in sample volume in the case of thin films can be overcome bytuning X-rays to the pi* resonance of PS or PI. Using RSOXS, we study themicrophase ordering of cylinder- and phere-forming PS-b-PI thin films andcompare these results to position space data obtained by atomic forcemicroscopy. Our ability to examine large sample areas (~;9000 mu m2) byRSOXS enables unambiguous identification of the lateral lattice structurein the thin films. In the case of the sphere-forming copolymer thin film,where the spheres are hexagonally arranged, the average sphere-to-spherespacing is between the bulk (body-centered cubic) nearest neighbor andbulk unit cell spacings. In the case of the cylinder-forming copolymerthin film, the cylinder-to-cylinder spacing is within experimental errorof that obtained in the bulk.

New neutron-based isotopic analytical methods; An explorative study of resonance capture and incoherent scattering

NARCIS (Netherlands)

Perego, R.C.

2004-01-01

Two novel neutron-based analytical techniques have been treated in this thesis, Neutron Resonance Capture Analysis (NRCA), employing a pulsed neutron source, and Neutron Incoherent Scattering (NIS), making use of a cold neutron source. With the NRCA method isotopes are identified by the

Computational time-resolved and resonant x-ray scattering of strongly correlated materials

Energy Technology Data Exchange (ETDEWEB)

Bansil, Arun [Northeastern Univ., Boston, MA (United States)

2016-11-09

Basic-Energy Sciences of the Department of Energy (BES/DOE) has made large investments in x-ray sources in the U.S. (NSLS-II, LCLS, NGLS, ALS, APS) as powerful enabling tools for opening up unprecedented new opportunities for exploring properties of matter at various length and time scales. The coming online of the pulsed photon source, literally allows us to see and follow the dynamics of processes in materials at their natural timescales. There is an urgent need therefore to develop theoretical methodologies and computational models for understanding how x-rays interact with matter and the related spectroscopies of materials. The present project addressed aspects of this grand challenge of x-ray science. In particular, our Collaborative Research Team (CRT) focused on developing viable computational schemes for modeling x-ray scattering and photoemission spectra of strongly correlated materials in the time-domain. The vast arsenal of formal/numerical techniques and approaches encompassed by the members of our CRT were brought to bear through appropriate generalizations and extensions to model the pumped state and the dynamics of this non-equilibrium state, and how it can be probed via x-ray absorption (XAS), emission (XES), resonant and non-resonant x-ray scattering, and photoemission processes. We explored the conceptual connections between the time-domain problems and other second-order spectroscopies, such as resonant inelastic x-ray scattering (RIXS) because RIXS may be effectively thought of as a pump-probe experiment in which the incoming photon acts as the pump, and the fluorescent decay is the probe. Alternatively, when the core-valence interactions are strong, one can view K-edge RIXS for example, as the dynamic response of the material to the transient presence of a strong core-hole potential. Unlike an actual pump-probe experiment, here there is no mechanism for adjusting the time-delay between the pump and the probe. However, the core hole

Quantum trajectories in elastic atom-surface scattering: threshold and selective adsorption resonances.

Science.gov (United States)

Sanz, A S; Miret-Artés, S

2005-01-01

The elastic resonant scattering of He atoms off the Cu(117) surface is fully described with the formalism of quantum trajectories provided by Bohmian mechanics. Within this theory of quantum motion, the concept of trapping is widely studied and discussed. Classically, atoms undergo impulsive collisions with the surface, and then the trapped motion takes place covering at least two consecutive unit cells. However, from a Bohmian viewpoint, atom trajectories can smoothly adjust to the equipotential energy surface profile in a sort of sliding motion; thus the trapping process could eventually occur within one single unit cell. In particular, both threshold and selective adsorption resonances are explained by means of this quantum trapping considering different space and time scales. Furthermore, a mapping between each region of the (initial) incoming plane wave and the different parts of the diffraction and resonance patterns can be easily established, an important issue only provided by a quantum trajectory formalism. (c) 2005 American Institute of Physics.

RADAR upper hybrid resonance scattering diagnostics of small-scale fluctuations and waves in tokamak plasmas

International Nuclear Information System (INIS)

Bulyiginskiy, D.G.; Gurchenko, A.D.; Gusakov, E.Z.; Korkin, V.V.; Larionov, M.M.; Novik, K.M.; Petrov, Yu.V.; Popov, A.Yu.; Saveliev, A.N.; Selenin, V.L.; Stepanov, A.Yu.

2001-01-01

The upper hybrid resonance (UHR) scattering technique possessing such merits as one-dimensional probing geometry, enhancement of cross section, and fine localization of scattering region is modified in the new diagnostics under development to achieve wave number resolution. The fluctuation wave number is estimated in the new technique from the scattering signal time delay measurements. The feasibility of the scheme is checked in the proof of principal experiment in a tokamak. The time delay of the UHR scattering signal exceeding 10 ns is observed. The small scale low frequency density fluctuations are investigated in the UHR RADAR backscattering experiment. The UHR cross-polarization scattering signal related to small scale magnetic fluctuations is observed. The lower hybrid (LH) wave propagation and both linear and nonlinear wave conversion are investigated. The small wavelength (λ≤0.02 cm) high number ion Bernstein harmonics, resulting from the linear wave conversion of the LH wave are observed in a tokamak plasma for the first time

Probing edge-activated resonant Raman scattering from mechanically exfoliated 2D MoO3 nanolayers

International Nuclear Information System (INIS)

Yano, Taka-aki; Yoshida, Keisuke; Hayashi, Tomohiro; Hara, Masahiko; Hayamizu, Yuhei; Ohuchi, Fumio

2015-01-01

We report spatially resolved vibrational analysis of mechanically exfoliated single-crystalline α-MoO 3 nanolayers. Raman scattering from α-MoO 3 was enhanced predominantly at the outside edges of the nanolayers. The enhanced Raman scattering at the edges was attributed primarily to the enhanced resonant Raman effect caused by a high density of oxygen vacancies localized at the edges. The localized vacancy sites corresponded to a non-stoichiometric phase of MoO 3 , which would provide reactive sites with high catalytic activity. (paper)

Enhancing the performances of a resonance detector spectrometer for deep inelastic neutron scattering measurements

International Nuclear Information System (INIS)

Filabozzi, A.; Pace, E.; Pietropaolo, A.

2012-01-01

The possibility is explored to sum up neutron Compton profiles at different scattering angles in deep inelastic neutron scattering measurements within the Resonance Detector (RD) configuration to enhance the statistics for a more reliable extraction of the momentum distribution of the constituents in the target. The RD configuration allows to select the energy of the scattered neutrons up to several tens of electron Volt, thus accessing energy and wave vector transfers well above 1 eV and 30 Å −1 , respectively. In the high-q/ω regime, the final state effects could be considered as negligible, as shown in a series of simulations using a Monte Carlo method with different inverse geometry instrument setups. The simulations show that it could be possible to conceive an instrument set up where the RD configuration allows the proper summation of several spectra at different scattering angles, providing a good separation of the proton recoil signal from that of the heavier atoms, thus avoiding the cell subtraction by fitting procedure.

The effect of background absorption on the compound cross-section in resonance scattering

International Nuclear Information System (INIS)

Frenkel, A.

1976-01-01

The effect of channel-channel correlations in the compound cross-section is studied in a model of a resonance above a compound background characterized by equal absorption in all open channels. A general rule which cannot be derived from unitarity alone is proved for the fluctuating cross-section. It provides new understanding of level-level correlations in scattering through compound nucleus states. (author)

Scattering properties of vein induced localized surface plasmon resonances on a gold disk

KAUST Repository

Amin, Muhammad

2011-12-01

It is demonstrated via simulations that a gold nano-disk with a non-concentric cavity supports localized surface plasmon resonances over a frequency band that includes the visible and the near-infrared parts of the spectrum. The charge distribution on the disk indicates that the two distinct peaks in the scattering cross section are due to the (hybridized) higher-order plasmon modes; plasmon hybridization that involves the dipole modes of the disk and the cavity enforces the "coupling" of the plane-wave excitation to the originally-dark higher-order modes. It is further demonstrated that the resonance frequencies can be tuned by varying the radius of the embedded non-concentric cavity. The near-field enhancement observed at these two tunable resonance frequencies suggests that the proposed structure can be used as a substrate in surface enhanced spectroscopy applications. © 2011 IEEE.

A New Scaling Law of Resonance in Total Scattering Cross Section in Gases

Science.gov (United States)

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

Application of nuclear resonance scattering for in vivo measurements

International Nuclear Information System (INIS)

Wielopolski, L.; Vartsky, D.; Cohn, S.H.

1983-01-01

Nuclear resonance scattering is applied in our laboratory to measure hepatic and cardiac iron overload. For iron analysis, a gaseous source of 4 mg MnCl 2 is introduced into an evacuated quartz vial. Following irradiation in a nuclear reactor, 56 Mn decays by beta emission to the 847-keV level of 56 Fe, which subsequently decays to the ground state of 56 Fe with a 7 ps half-life. The principal aim of this work is to evaluate the efficacy of the iron chelation therapy. Serial measurements over a time period of 6 to 12 months of a given patient will enable us to see how the iron is removed from the critical organs

The Strength of Chaos: Accurate Simulation of Resonant Electron Scattering by Many-Electron Ions and Atoms in the Presence of Quantum Chaos

Science.gov (United States)

2017-01-20

AFRL-AFOSR-JP-TR-2017-0012 The Strength of Chaos : accurate simulation of resonant electron scattering by many-electron ions and atoms in the presence...of quantum chaos Igor Bray CURTIN UNIVERSITY OF TECHNOLOGY Final Report 01/20/2017 DISTRIBUTION A: Distribution approved for public release. AF...SUBTITLE The Strength of Chaos : accurate simulation of resonant electron scattering by many- electron ions and atoms in the presence of quantum chaos

Resonant scattering of energetic electrons in the plasmasphere by monotonic whistler-mode waves artificially generated by ionospheric modification

Directory of Open Access Journals (Sweden)

S. S. Chang

2014-05-01

Full Text Available Modulated high-frequency (HF heating of the ionosphere provides a feasible means of artificially generating extremely low-frequency (ELF/very low-frequency (VLF whistler waves, which can leak into the inner magnetosphere and contribute to resonant interactions with high-energy electrons in the plasmasphere. By ray tracing the magnetospheric propagation of ELF/VLF emissions artificially generated at low-invariant latitudes, we evaluate the relativistic electron resonant energies along the ray paths and show that propagating artificial ELF/VLF waves can resonate with electrons from ~ 100 keV to ~ 10 MeV. We further implement test particle simulations to investigate the effects of resonant scattering of energetic electrons due to triggered monotonic/single-frequency ELF/VLF waves. The results indicate that within the period of a resonance timescale, changes in electron pitch angle and kinetic energy are stochastic, and the overall effect is cumulative, that is, the changes averaged over all test electrons increase monotonically with time. The localized rates of wave-induced pitch-angle scattering and momentum diffusion in the plasmasphere are analyzed in detail for artificially generated ELF/VLF whistlers with an observable in situ amplitude of ~ 10 pT. While the local momentum diffusion of relativistic electrons is small, with a rate of −7 s−1, the local pitch-angle scattering can be intense near the loss cone with a rate of ~ 10−4 s−1. Our investigation further supports the feasibility of artificial triggering of ELF/VLF whistler waves for removal of high-energy electrons at lower L shells within the plasmasphere. Moreover, our test particle simulation results show quantitatively good agreement with quasi-linear diffusion coefficients, confirming the applicability of both methods to evaluate the resonant diffusion effect of artificial generated ELF/VLF whistlers.

Excitation of giant resonances through inelastic scattering of 170 at 84 MeV/u. Fission decay of giant resonances

International Nuclear Information System (INIS)

Cabot, C.; Barrette, J.; Mark, S.K.; Turcotte, R.; Xing, J.; Van der Woude, A.; Van Den Berg, A. M.

1991-01-01

Inelastic scattering of 84 MeV/u 17 0 projectiles have been used to excite the giant resonances (GR) in various nuclei ranging from A=60 to A=232. For the isoscalar giant quadrupole resonance (ISGQR), the energy and width of the resonance, as well as the EWSR obtained from the measured cross sections, are in agreement with the known systematics for A>40. The observed GMR strengths are close to 100% EWRS and are consistent with other recent experimental results using heavy ion projectiles. These results lead to a somewhat different picture than that provided by previous studies using light projectiles. Strength is also observed at high excitation energy. The analysis of these resonances is in progress. Our study of the fission decay of GR in 232 Th leads to a somewhat different conclusion than previously deduced from data obtained with light ion projectiles, where no evidence for the fission decay of the ISGQR has been found. In the present work, due to the very good peak-to-continuum ratio, a structure is observed in the fission coincidence spectrum around 10 MeV which can be attributed to the fission decay of giant resonances. The measured fission probability is consistent with a statistical decay of the ISGQR. 10 figs

Scattering phases for particles with nonzero orbital momenta and resonance regimes in the Pais approximation

International Nuclear Information System (INIS)

Bruk, Yulii M; Voloshchuk, Aleksandr N

2012-01-01

The functional Pais equation for scattering phases with nonzero orbital momenta is solved in the case of low-energy particles. For short-range screened potentials, in particular, Yukawa or Thomas-Fermi potentials, the Pais equation is shown to reduce to transcendental equations. For the potentials varying ∼r - n , n > 0, simple algebraic equations are obtained for determining the phases δ l , l≠0. Possible applications of the Pais approximation to the problem of finding resonance regimes in the scattering of low-energy particles with nonzero orbital momenta are discussed. (methodological notes)

Stimulated scattering of electromagnetic waves carrying orbital angular momentum in quantum plasmas.

Science.gov (United States)

Shukla, P K; Eliasson, B; Stenflo, L

2012-07-01

We investigate stimulated scattering instabilities of coherent circularly polarized electromagnetic (CPEM) waves carrying orbital angular momentum (OAM) in dense quantum plasmas with degenerate electrons and nondegenerate ions. For this purpose, we employ the coupled equations for the CPEM wave vector potential and the driven (by the ponderomotive force of the CPEM waves) equations for the electron and ion plasma oscillations. The electrons are significantly affected by the quantum forces (viz., the quantum statistical pressure, the quantum Bohm potential, as well as the electron exchange and electron correlations due to electron spin), which are included in the framework of the quantum hydrodynamical description of the electrons. Furthermore, our investigation of the stimulated Brillouin instability of coherent CPEM waves uses the generalized ion momentum equation that includes strong ion coupling effects. The nonlinear equations for the coupled CPEM and quantum plasma waves are then analyzed to obtain nonlinear dispersion relations which exhibit stimulated Raman, stimulated Brillouin, and modulational instabilities of CPEM waves carrying OAM. The present results are useful for understanding the origin of scattered light off low-frequency density fluctuations in high-energy density plasmas where quantum effects are eminent.

Reflectivity of stimulated back scattering in a homogeneous-slab medium in the case of negligible pump-wave damping

International Nuclear Information System (INIS)

Cho, G.S.; Cho, B.H.

1981-01-01

As to the backscatter instability which is one of nonlinear three-wave resonant interactions, the reflectivity(r) in the case of homogeneous-slab medium is calculated, assuming all the three wavepackets negligible damping caused by medium. The expression has turned out such that r = tanh 2 KAsub(p)L, where K, Asub(p), and L are the constant coupling coefficient, the constant pump-wave amplitude, and the thickness of the medium engaged in the interaction each. When this result is interpreted in terms of the stimulated Brillouin back-scattering in a so-called underdense plasma in controlled fusion, we find the reflectivity twice as large as that by others in the limit of large pump-wave damping, and unfitting to former experiments in the independence on the incident laser-light intensity. We see the incompatibility rise chiefly from neglecting the damping of pump-wave in the plasma. In contrast to the former results by others in the limit of large pump-wave damping, our result might be regarded as that for cases of negligible pump-wave damping, in general stimulated back-scattering phenomena. (author)

Cooperative scattering of scalar waves by optimized configurations of point scatterers

Science.gov (United States)

Schäfer, Frank; Eckert, Felix; Wellens, Thomas

2017-12-01

We investigate multiple scattering of scalar waves by an ensemble of N resonant point scatterers in three dimensions. For up to N = 21 scatterers, we numerically optimize the positions of the individual scatterers, to maximize the total scattering cross section for an incoming plane wave, on the one hand, and to minimize the decay rate associated to a long-lived scattering resonance, on the other. In both cases, the optimum is achieved by configurations where all scatterers are placed on a line parallel to the direction of the incoming plane wave. The associated maximal scattering cross section increases quadratically with the number of scatterers for large N, whereas the minimal decay rate—which is realized by configurations that are not the same as those that maximize the scattering cross section—decreases exponentially as a function of N. Finally, we also analyze the stability of our optimized configurations with respect to small random displacements of the scatterers. These results demonstrate that optimized configurations of scatterers bear a considerable potential for applications such as quantum memories or mirrors consisting of only a few atoms.

New light on the Kr-(4p55s2) Feshbach resonances: high-resolution electron scattering experiments and B-spline R-matrix calculations

International Nuclear Information System (INIS)

Hoffmann, T H; Ruf, M-W; Hotop, H; Zatsarinny, O; Bartschat, K; Allan, M

2010-01-01

In a joint experimental and theoretical effort, we carried out a detailed study of electron scattering from Kr atoms in the energy range of the low-lying Kr - (4p 5 5s 2 ) Feshbach resonances. Absolute angle-differential cross sections for elastic electron scattering were measured over the energy range 9.3-10.3 eV with an energy width of about 13 meV at scattering angles between 10 deg. and 180 deg. Using several sets of elastic scattering phase shifts, a detailed analysis of the sharp Kr - (4p 5 5s 2 2 P 3/2 ) resonance was carried out, resulting in a resonance width of Γ 3/2 3.6(2) meV. By direct comparison with the position of the Ar - (3p 5 4s 2 2 P 3/2 ) resonance, the energy for the Kr - (4p 5 5s 2 2 P 3/2 ) resonance was determined as E 3/2 = 9.489(3) eV. A Fano-type fit of the higher lying Kr - (4p 5 5s 2 2 P 1/2 ) resonance yielded the resonance parameters Γ 1/2 = 33(5) meV and E 1/2 = 10.126(4) eV. In order to obtain additional insights, B-spline R-matrix calculations were performed for both the elastic and the inelastic cross sections above the threshold for 4p 5 5s excitation. They provide the total and angle-differential cross sections for excitation of long-lived and short-lived levels of the 4p 5 5s configuration in Kr and branching ratios for the decay of the Kr - (4p 5 5s 2 2 P 1/2 ) resonance into the three available exit channels. The results are compared with selected experimental data.

Time resolved resonant inelastic X-ray scattering: A supreme tool to understand dynamics in solids and molecules

International Nuclear Information System (INIS)

Beye, M.; Wernet, Ph.; Schüßler-Langeheine, C.; Föhlisch, A.

2013-01-01

Highlights: •The high specificity of RIXS ideally suits time-resolved measurements. •Methods relating to the core hole lifetime cover the low femtosecond regime. •Pump-probe methods are used starting at sub-ps time scales. •FELs and synchrotrons are useful for pump-probe studies. •Examples from solid state dynamics and molecules are discussed. -- Abstract: Dynamics in materials typically involve different degrees of freedom, like charge, lattice, orbital and spin in a complex interplay. Time-resolved resonant inelastic X-ray scattering (RIXS) as a highly selective tool can provide unique insight and follow the details of dynamical processes while resolving symmetries, chemical and charge states, momenta, spin configurations, etc. In this paper, we review examples where the intrinsic scattering duration time is used to study femtosecond phenomena. Free-electron lasers access timescales starting in the sub-ps range through pump-probe methods and synchrotrons study the time scales longer than tens of ps. In these examples, time-resolved resonant inelastic X-ray scattering is applied to solids as well as molecular systems

Determination of proteins and carbohydrates in the effluents from wastewater treatment bioreactors using resonance light-scattering method.

Science.gov (United States)

Zhang, Meng-Lin; Sheng, Guo-Ping; Yu, Han-Qing

2008-07-01

A simple and sensitive method was developed for the determination of low-concentration proteins and carbohydrates in the effluents from biological wastewater treatment reactors using resonance light-scattering (RLS) technique. Two ionic dyes, Congo red and Neutral red were, respectively used as an RLS probes for the determination of proteins and carbohydrates. This method is based on the interactions between biomacromolecules and dyes, which cause a substantial increase in the resonance scattering signal of dyes in the wavelength range of 200-650 nm. The characteristics of RLS spectra of the macromolecule-dye complexes, influencing factors, and optimum analytical conditions for the measurement were explored. The method was satisfactorily applied to the measurement of proteins and carbohydrates in the effluents from 10 aerobic or anaerobic bioreactors, and a high sensitivity were achieved.

Numerical computations of the Lennard-Jones resonances and ''relative displacements'' of the scattered atomic beams from the system He/LiF(001)

International Nuclear Information System (INIS)

Garcia, N.

1976-01-01

This paper considers the effect of the attractive part of the interaction potential on the scattering of He atoms from a LiF(001) surface. We calculate, in particular, the Lennard-Jones resonances on the intensities and the phases of the scattered amplitudes, using a square well in the front of a hard corrugated surface model. We show that the amplitudes for incident energies smaller than the depth of the well are dominated by the resonances

Brillouin-zone database on the Bilbao Crystallographic Server.

Science.gov (United States)

Aroyo, Mois I; Orobengoa, Danel; de la Flor, Gemma; Tasci, Emre S; Perez-Mato, J Manuel; Wondratschek, Hans

2014-03-01

The Brillouin-zone database of the Bilbao Crystallographic Server (http://www.cryst.ehu.es) offers k-vector tables and figures which form the background of a classification of the irreducible representations of all 230 space groups. The symmetry properties of the wavevectors are described by the so-called reciprocal-space groups and this classification scheme is compared with the classification of Cracknell et al. [Kronecker Product Tables, Vol. 1, General Introduction and Tables of Irreducible Representations of Space Groups (1979). New York: IFI/Plenum]. The compilation provides a solution to the problems of uniqueness and completeness of space-group representations by specifying the independent parameter ranges of general and special k vectors. Guides to the k-vector tables and figures explain the content and arrangement of the data. Recent improvements and modifications of the Brillouin-zone database, including new tables and figures for the trigonal, hexagonal and monoclinic space groups, are discussed in detail and illustrated by several examples.

Gold split-ring resonators (SRRs) as substrates for surface-enhanced raman scattering

KAUST Repository

Yue, Weisheng

2013-10-24

We used gold split ring resonators (SRRs) as substrates for surface-enhanced Raman scattering (SERS). The arrays of SRRs were fabricated by electron-beam lithography in combination with plasma etching. In the detection of rhodamine 6G (R6G) molecules, SERS enhancement factors of the order of 105 was achieved. This SERS enhancement increased as the size of the split gap decrease as a consequence of the matching between the resonance wavelength of the SRRs and the excitation wavelength of SERS. As the size of the split gap decreased, the localized surface plasmon resonance shifted to near the excitation wavelength and, thus, resulted in the increase in the electric field on the nanostructures. We used finite integration method (FIT) to simulate numerically the electromagnetic properties of the SRRs. The results of the simulation agreed well with our experimental observations. We anticipate this work will provide an approach to manipulate the SERS enhancement by modulating the size of split gap with SRRs without affecting the area and structural arrangement. © 2013 American Chemical Society.

Gold split-ring resonators (SRRs) as substrates for surface-enhanced raman scattering

KAUST Repository

Yue, Weisheng; Yang, Yang; Wang, Zhihong; Chen, Longqing; Wang, Xianbin

2013-01-01

We used gold split ring resonators (SRRs) as substrates for surface-enhanced Raman scattering (SERS). The arrays of SRRs were fabricated by electron-beam lithography in combination with plasma etching. In the detection of rhodamine 6G (R6G) molecules, SERS enhancement factors of the order of 105 was achieved. This SERS enhancement increased as the size of the split gap decrease as a consequence of the matching between the resonance wavelength of the SRRs and the excitation wavelength of SERS. As the size of the split gap decreased, the localized surface plasmon resonance shifted to near the excitation wavelength and, thus, resulted in the increase in the electric field on the nanostructures. We used finite integration method (FIT) to simulate numerically the electromagnetic properties of the SRRs. The results of the simulation agreed well with our experimental observations. We anticipate this work will provide an approach to manipulate the SERS enhancement by modulating the size of split gap with SRRs without affecting the area and structural arrangement. © 2013 American Chemical Society.

Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering

Directory of Open Access Journals (Sweden)

Yanli Liu

2015-01-01

Full Text Available The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with the theoretical calculation result, taking lattice mismatch and thermal mismatch into account together. This good agreement indicates that the UV near-resonant Raman scattering can be a direct and effective method to characterize the stress state in thin AlGaN barrier layer of AlGaN/GaN HEMT heterostructures.

Attenuation process of the longitudinal phonon mode in a TeO2 crystal in the 20-GHz range

Science.gov (United States)

Ohno, S.; Sonehara, T.; Tatsu, E.; Koreeda, A.; Saikan, S.

2017-06-01

We experimentally investigated the hypersonic attenuation process of a longitudinal mode (L-mode) sound wave in TeO2 from room temperature to a lower temperature using Brillouin scattering and impulsive stimulated thermal scattering (ISTS) measurements. For precise measurement of the Brillouin linewidth at low temperatures, whereby the mean free path of the phonon becomes longer than the sample length, it is indispensable that the phonon should propagate along the phonon-resonance direction. To figure out the suitable direction, we defined two indices characterizing a degree of phonon divergence and a purity of propagation direction. The best direction that we found from these indices is [110] direction in TeO2, and it was used to discuss the temperature and frequency dependences of Brillouin spectra. We extracted the temperature dependence of the attenuation rate of T4 from the modulated Brillouin spectra due to the phonon resonance below Debye temperature. The frequency dependence ω1 of the hypersonic attenuation was also estimated from the polarization dependence of the Brillouin linewidth. Theoretically, it predicted that the L-mode phonon attenuation at low temperatures in TeO2 is a result of Herring's process, which shows the attenuation behavior of ω2T3 . The ω1T4 dependence is not allowed in Herring's process but is allowed by the L +L →L process, which has been considered to be forbidden so far. We evaluated the thermal phonon lifetime using ISTS and established that it was finite even at 20 K, thereby allowing the L +L →L process. Therefore, we conclude that the L +L →L process dominates the attenuation of an L-mode phonon in TeO2 in the low-temperature region.

Electron Dynamics in the Core-Excited CS_{2} Molecule Revealed through Resonant Inelastic X-Ray Scattering Spectroscopy

Directory of Open Access Journals (Sweden)

T. Marchenko

2015-08-01

Full Text Available We present an experimental and theoretical study of resonant inelastic x-ray scattering (RIXS in the carbon disulphide CS_{2} molecule near the sulfur K-absorption edge. We observe a strong evolution of the RIXS spectral profile with the excitation energy tuned below the lowest unoccupied molecular orbital (LUMO absorption resonance. The reason for this is twofold. Reducing the photon energy in the vicinity of the LUMO absorption resonance leads to a relative suppression of the LUMO contribution with respect to the emission signal from the higher unoccupied molecular orbitals, which results in the modulation of the total RIXS profile. At even larger negative photon-energy detuning from the resonance, the excitation-energy dependence of the RIXS profile is dominated by the onset of electron dynamics triggered by a coherent excitation of multiple electronic states. Furthermore, our study demonstrates that in the hard x-ray regime, localization of the S 1s core hole occurs in CS_{2} during the RIXS process because of the orientational dephasing of interference between the waves scattering on the two sulfur atoms. Core-hole localization leads to violation of the symmetry selection rules for the electron transitions observed in the spectra.

Investigation of resonant Raman scattering in type II GaAs/AlAs superlattices

International Nuclear Information System (INIS)

Choi, H.

2001-01-01

As a consequence of the band alignment in GaAs/AIAs superlattices (SLs) and the indirect nature of bulk AIAs, quantum confinement can be used to engineer a Type II system. This produces an electron population in the AIAs longitudinal (X z ) or transverse (X xy ) zone-edge states, which is separated in both direct and reciprocal space from the hole population in the GaAs zone-centre (Γ) states. This thesis is an investigation of the electronic and vibrational structure of Type II GaAs/AIAs SLs using theoretical models and spectroscopic techniques, with special emphasis on Type II resonant Raman (RR) scattering. The majority of this thesis concerns short-period GaAs/AIAs SLs with X z as the lowest conduction band state. A model of the SL electronic band structure is presented, including the effects of interband Γ-X z mixing and the X-point camel's back structure. Interband mixing makes Γ-X z radiative transitions observable in photoluminescence (PL) and RR experiments. Phonon-assisted transitions from the X z state are also observed in PL experiments. Several of the participating phonon modes are unambiguously identified, in good agreement with recent reports. This thesis presents the first detailed experimental and theoretical study of Type II RR scattering from the incoming channel of the X z -related Type II bandgap. The X z - related Type II incoming RR spectra in the GaAs optic phonon region are compared with the Γ-related Type I outgoing RR spectra within several theoretical models. Thereby, the mechanisms of the Type II RR scattering, the origins of the RR lineshape and the polarisation dependence, are fully explained, clarifying the spectral features observed in the GaAs zone-centre optic phonon region. The Type II resonance also allows the observation of zone boundary (X-point) phonons from intervalley (IV) scattering. A model of the IV electron-phonon interaction involving X conduction band electrons and zone boundary phonons in Type II SLs is presented

Scattering phases for meson and baryon resonances on general moving-frame lattices

Energy Technology Data Exchange (ETDEWEB)

Goeckeler, M. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Lage, M.; Rusetsky, A. [Bonn Univ. (Germany). Helmholtz-Inst. fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics; Meissner, U.G. [Bonn Univ. (Germany). Helmholtz-Inst. fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics; Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Forschungszentrum Juelich (Germany). Juelich Center for Hadron Physics and JARA - High Performance Computing; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics

2012-06-15

A proposal by Luescher enables one to compute the scattering phases of elastic two-body systems from the energy levels of the lattice Hamiltonian in a finite volume. In this work we generalize the formalism to S-, P- and D-wave meson and baryon resonances, and general total momenta. Employing nonvanishing momenta has several advantages, among them making a wider range of energy levels accessible on a single lattice volume and shifting the level crossing to smaller values of m{sub {pi}}L.

Schwinger–Keldysh canonical formalism for electronic Raman scattering

Energy Technology Data Exchange (ETDEWEB)

Su, Yuehua, E-mail: suyh@ytu.edu.cn

2016-03-01

Inelastic low-energy Raman and high-energy X-ray scatterings have made great progress in instrumentation to investigate the strong electronic correlations in matter. However, theoretical study of the relevant scattering spectrum is still a challenge. In this paper, we present a Schwinger–Keldysh canonical perturbation formalism for the electronic Raman scattering, where all the resonant, non-resonant and mixed responses are considered uniformly. We show how to use this formalism to evaluate the cross section of the electronic Raman scattering off an one-band superconductor. All the two-photon scattering processes from electrons, the non-resonant charge density response, the elastic Rayleigh scattering, the fluorescence, the intrinsic energy-shift Raman scattering and the mixed response, are included. In the mean-field superconducting state, Cooper pairs contribute only to the non-resonant response. All the other responses are dominated by the single-particle excitations and are strongly suppressed due to the opening of the superconducting gap. Our formalism for the electronic Raman scattering can be easily extended to study the high-energy resonant inelastic X-ray scattering.

Inelastic Light Scattering Processes

Science.gov (United States)

Fouche, Daniel G.; Chang, Richard K.

1973-01-01

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

Brillouin optical correlation domain analysis in composite material beams

DEFF Research Database (Denmark)

Stern, Yonatan; London, Yosef; Preter, Eyal

2017-01-01

Structural health monitoring is a critical requirement in many composites. Numerous monitoring strategies rely on measurements of temperature or strain (or both), however these are often restricted to point-sensing or to the coverage of small areas. Spatially-continuous data can be obtained...... with optical fiber sensors. In this work, we report high-resolution distributed Brillouin sensing over standard fibers that are embedded in composite structures. A phase-coded, Brillouin optical correlation domain analysis (B-OCDA) protocol was employed, with spatial resolution of 2 cm and sensitivity of 1 °K...... or 20 micro-strain. A portable measurement setup was designed and assembled on the premises of a composite structures manufacturer. The setup was successfully utilized in several structural health monitoring scenarios: (a) monitoring the production and curing of a composite beam over 60 h; (b...

1s2p resonant inelastic x-ray scattering in a-Fe2O3

NARCIS (Netherlands)

Caliebe, W.A.; Kao, C.-C.; Hastings, J.B.; Taguchi, M.; Kotani, A.; Uozumi, T.; Groot, F.M.F. de

1998-01-01

We report experimental and theoretical results on the Fe K edge x-ray absorption spectrum and 1s2p resonant inelastic x-ray scattering (RIXS) spectra in a-Fe2O3 . The results are interpreted using an FeO6^9- cluster model with intra-atomic multiplet coupling and interatomic covalency

Fiber optic particle plasmon resonance sensor based on plasmonic light scattering interrogation

International Nuclear Information System (INIS)

Lin, H.Y.; Huang, C.H.; Chau, L.K.

2012-01-01

A highly sensitive fiber optic particle plasmon resonance sensor (FO-PPR) is demonstrated for label-free biochemical detection. The sensing strategy relies on interrogating the plasmonic scattering of light from gold nanoparticles on the optical fiber in response to the surrounding refractive index changes or molecular binding events. The refractive index resolution is estimated to be 3.8 x 10 -5 RIU. The limit of detection for anti-DNP antibody spiked in buffer is 1.2 x 10 -9 g/ml (5.3 pM) by using the DNP-functionalized FO-PPR sensor. The image processing of simultaneously recorded plasmonic scattering photographs at different compartments of the sensor is also demonstrated. Results suggest that the compact sensor can perform multiple independent measurements simultaneously by means of monitoring the plasmonic scattering intensity via photodiodes or a CCD. The potential of using a combination of different kinds of noble metal nanoparticles with different types of functionalized probes in multiple cascaded detection windows on a single fiber to become an inexpensive and ultrasensitive linear-array sensing platform for higher-throughput biochemical detection is provided. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Energy and polarization dependence of resonant inelastic X-ray scattering in Nd2CuO4

International Nuclear Information System (INIS)

Hill, J.P.; Kao, C.C.; Haemaelaeinen, K.

1998-01-01

The authors report the energy and polarization dependence of resonant inelastic x-ray scattering from Nd 2 CuO 4 . An energy loss feature at ∼6 eV is observed in the vicinity of the Cu K-edge. Numerical calculations based on the Anderson impurity model identify this as a charge transfer excitation to the anti-bonding state. The incident polarization is shown to select the intermediate states participating in the resonance process. Resonances are observed at 8,990 eV and 9,000 eV with the incident polarization perpendicular and parallel to the CuO planes, respectively. In contrast to the single-site model calculations, no resonances are observed associated with the 1s3d 10 L intermediate states, suggesting non-local effects play a role

Proportional Counter Calibration and Analysis for 12C + p Resonance Scattering

Science.gov (United States)

Nelson, Austin; Rogachev, Grigory; Uberseder, Ethan; Hooker, Josh; Koshchiy, Yevgen

2014-09-01

Light exotic nuclei provide a unique opportunity to test the predictions of modern ab initio theoretical calculations near the drip line. In ab initio approaches, nuclear structure is described starting from bare nucleon-nucleon and three-nucleon interactions. Calculations are very heavy and can only be performed for the lightest nuclei (A objective of this project was to test the performance and perform position calibration of this proportional counter array. The test was done using 12C beam. The excitation function for 12C + p elastic scattering was measured and calibration of the proportional counter was performed using known resonances in 13N. The method of calibration, including solid angle calculations, normalization corrections, and position calibration will be presented. Light exotic nuclei provide a unique opportunity to test the predictions of modern ab initio theoretical calculations near the drip line. In ab initio approaches, nuclear structure is described starting from bare nucleon-nucleon and three-nucleon interactions. Calculations are very heavy and can only be performed for the lightest nuclei (A objective of this project was to test the performance and perform position calibration of this proportional counter array. The test was done using 12C beam. The excitation function for 12C + p elastic scattering was measured and calibration of the proportional counter was performed using known resonances in 13N. The method of calibration, including solid angle calculations, normalization corrections, and position calibration will be presented. Funded by DOE and NSF-REU Program; Grant No. PHY-1263281.

A Brillouin scattering study of hydrous basaltic glasses: the effect of H2O on their elastic behavior and implications for the densities of basaltic melts

Science.gov (United States)

Wu, Lei; Yang, De-Bin; Liu, Jun-Xiu; Hu, Bo; Xie, Hong-Sen; Li, Fang-Fei; Yu, Yang; Xu, Wen-Liang; Gao, Chun-Xiao

2017-06-01

Hydrous basalt glasses with water contents of 0-6.82% were synthesized using a multi-anvil press at 1.0-2.0 GPa and 1200-1400 °C. The starting materials were natural Mesozoic basalts from the eastern North China Craton (NCC). Their sound velocities and elastic properties were measured by Brillouin scattering spectroscopy. The longitudinal ( V P) and shear ( V S) wave velocities decreased with increasing water content. Increasing the synthesis pressure resulted in the glass becoming denser, and finally led to an increase in V P. As the degree of depolymerization increased, the V P, V S, and shear and bulk moduli of the hydrous basalt glasses decreased, whereas the adiabatic compressibility increased. The partial molar volumes of water (ν) under ambient conditions were independent of composition, having values of 11.6 ± 0.8, 10.9 ± 0.6 and 11.5 ± 0.5 cm3/mol for the FX (Feixian), FW (Fuxin), and SHT (Sihetun) basalt glasses, respectively. However, the {{V}_{{{{H}}_{{2}}}{O}}} values measured at elevated temperatures and pressures are increasing with increasing temperature or decreasing pressure. The contrasting densities of these hydrous basalt melts with those previously reported for mid-ocean ridge basalt and preliminary reference Earth model data indicate that hydrous basalt melts may not maintain gravitational stability at the base of the upper mantle.

Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering

OpenAIRE

Yanli Liu; Xifeng Yang; Dunjun Chen; Hai Lu; Rong Zhang; Youdou Zheng

2015-01-01

The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV) near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO) phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with th...

Density functional simulation of resonant inelastic X-ray scattering experiments in liquids: acetonitrile.

Science.gov (United States)

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 (H 3 C-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 H 2 C-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.

Angular correlation, spin alignment, and systematics of mis-matched {sup 12}C+{sup 12}C inelastic scattering resonances

Energy Technology Data Exchange (ETDEWEB)

Wuosmaa, A.H.; Wiedenhoever, I.; Caggiano, J.; Carpenter, M.P.; Devlin, M.; Heinz, A.; Janssens, R.V.F.; Kondev, F.; Lauritsen, T.; Sarantites, D.G.; Sobotka, L.G.; Battacharyya, P

2003-10-09

Particle gamma-ray angular correlation measurements have been used to study the spin alignment and magnetic-substate population parameters for the 2{sup +}{sub 1} (4.443 MeV) state in {sup 12}C, populated in the {sup 12}C({sup 12}C,{sup 12}C[0{sup +}{sub 2}]){sup 12}C(2{sup +}{sub 1}) inelastic scattering reaction in the vicinity of a prominent, narrow peak in the scattering excitation function. The data show a strong alignment of the spin with the orbital angular momentum, and suggest that the cross section peak corresponds to a spin 14{sup +} resonance at E{sub c.m.}=28.0 MeV. This energy is close to that where a strong peak is also observed in the 0{sup +}{sub 1}+0{sup +}{sub 2} excitation function. A comparison between the data for these two channels lends some support to recent theoretical calculations of resonance behavior for angular-momentum-mismatched channels in {sup 12}C+{sup 12}C inelastic scattering.

Ferromagnetic resonance linewidth and two-magnon scattering in Fe1-xGdx thin films

Directory of Open Access Journals (Sweden)

Sheng Jiang

2017-05-01

Full Text Available Magnetization dynamics of Fe1-xGdx thin films (0 ≤ x ≤ 22% has been investigated by ferromagnetic resonance (FMR. Out-of-plane magnetic field orientation dependence of resonance field and linewidth has been measured. Resonance field and FMR linewidth have been fitted by the free energy of our system and Landau-Lifshitz-Gilbert (LLG equation. It is found that FMR linewidth contains huge extrinsic components including two-magnon scattering contribution and inhomogeneous broadening for FeGd alloy thin films. In addition, the intrinsic linewidth and real damping constants have been obtained by extracting the extrinsic linewidth. The damping constant enhanced from 0.011 to 0.038 as Gd dopants increase from 0 to 22% which originates from the enhancement of L-S coupling in FeGd thin films. Besides, gyromagnetic ratio, Landé factor g and magnetic anisotropy of our films have also been determined.

A dual-wavelength overlapping resonance Rayleigh scattering method for the determination of chondroitin sulfate with nile blue sulfate

Science.gov (United States)

Cui, Zhiping; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang

2011-12-01

A dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) method was developed to detect chondroitin sulfate (CS) with nile blue sulfate (NBS). At pH 3.0-4.0 Britton-Robinson (BR) buffer medium, CS interacted with NBS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequence doubling scattering (FDS) appeared and their intensities were enhanced greatly. Their maximum wavelengths were located at 303 nm (RRS), 362 nm (RRS), 588 nm (SOS) and 350 nm (FDS), respectively. The scattering intensities of the three methods were proportional to the concentration of CS in certain ranges. The methods had high sensitivity and the detection limits were between 1.5 and 7.1 ng mL -1. The DWO-RRS method had the highest sensitivity with the detection limit being 1.5 ng mL -1. The characteristics of the spectra and optimal reaction conditions of RRS method were investigated. The effects of coexistent substances on the determination of CS were evaluated. Owing to the high sensitivity, RRS method had been applied to the determination of CS in eye drops with satisfactory results. The recovery range was between 99.4% and 104.6% and the relative standard deviation (RSD) was between 0.4% and 0.8%. In addition, the reasons for RRS enhancement were discussed and the shape of ion-association complex was characterized by atomic force microscopy (AFM).

Resonant inelastic scattering at intermediate X-ray energies

CERN Document Server

Hague, C F; Journel, L; Gallet, J J; Rogalev, A; Krill, G; Kappler, J P

2000-01-01

We describe resonant inelastic X-ray scattering (RIXS) experiments and magnetic circular dichroism (MCD) in X-ray fluorescence performed in the 3-5 keV range. The examples chosen are X-ray fluorescence MCD of FeRh and RIXS experiments performed at the L/sub 3/ edge of Ce. Fe Rh is antiferromagnetic at room temperature but has a transition to the ferromagnetic state above 400 K. The Rh MCD signal is compared with an augmented spherical wave calculation. The experiment confirms the predicted spin polarization of the Rh 4d valence states. The RIXS measurements on Ce compounds and intermetallics address the problem of mixed valency especially in systems where degeneracy with the Fermi level remains small. Examples are taken from the 2p to (4f5d) /sup +1/ followed by 3d to 2p RIXS for a highly ionic compound CeF /sub 3/ and for almost gamma -like CeCuSi. (38 refs).

Dichroism and resonant diffraction in x-ray scattering by complex materials

International Nuclear Information System (INIS)

Collins, S P; Lovesey, S W; Balcar, E

2007-01-01

We survey universal concepts that influence dichroism and resonant Bragg diffraction, aiming to reach across the range of scientific disciplines that benefit from x-ray techniques, namely, chemistry, physics, life-sciences, and the science of materials. To this end, we adopt a top down discussion of the aspects of symmetry and concomitant selection rules. Starting from selection rules that can be deduced from the global condition that an observable quantity is unchanged on reversing the directions of both space and time separately, to selection rules that flow from bulk symmetry properties of electrons imposed by elements of a point group or crystal class to, finally, atomic selection rules that emerge from the details of the electronic structure. As a motivation for the latter we discuss, with a new calculation of the x-ray scattering length, E 1-M 1 absorption and scattering events that particularly interest scientists studying the chirality of life. In the main text there is modest use of mathematics, with appropriate details relegated to a few appendices. (topical review)

The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering