WorldWideScience

Sample records for nonlinear raman-nath diffraction

  1. Theoretical analysis and concept demonstration of a novel MOEMS accelerometer based on Raman-Nath diffraction

    Institute of Scientific and Technical Information of China (English)

    Zhang Zuwei; Wen Zhiyu; Hu Jing

    2012-01-01

    The design and simulation of a novel microoptoelectromechanical system (MOEMS) accelerometer based on Raman-Nath diffraction are presented.The device is planned to be fabricated by microelectromechanical system technology and has a different sensing principle than the other reported MOEMS accelerometers.The fundamental theories and principles of the device are discussed in detail,a 3D finite element simulation of the flexural plate wave delay line oscillator is provided,and the operation frequency around 40 MHz is calculated.Finally,a lecture experiment is performed to demonstrate the feasibility of the device.This novel accelerometer is proposed to have the advantages of high sensitivity and anti-radiation,and has great potential for various applications.

  2. Design and process test of a novel MOEMS accelerometer based on Raman-Nath diffraction

    Institute of Scientific and Technical Information of China (English)

    Zhang Zuwei; Wen Zhiyu; Shang Zhengguo; Li Dongling; Hu Jing

    2012-01-01

    A novel micro-opto-electro-mechanical system (MOEMS) accelerometer based on Raman-Nath diffraction is presented.It mainly consists of an FPW delay line oscillator and optical strip waveguides.The fundamental theories and principles of the device are introduced briefly.A flexural plate-wave delay-line oscillator is designed to work as an acousto-optic (AO) shifter,which has a Klein-Cook parameter of 0.38.Single-mode optical strip waveguides of 2 μm in width and thicknesses of 0.6 μm are designed by using the effective index method for light transmission.The E0y0 mode waveguide polarizers are designed to ensure the consistency of the light polarization in the waveguides.The fabrication process,based on (100) oriented,450-μm-thick silicon wafers is proposed in detail,and some difficulties in the process are discussed carefully.At last,a series of process tests are undertaken to solve the proposed problems.The results indicate that the proposed design and fabrication process of the device is dependable and realizable.

  3. Raman - Nath approximation for diffraction of atoms in the laser field taking into account spontaneous emission of atoms for ground and high energy level

    Science.gov (United States)

    Hovhannisayan, L.; Muradyan, A. Zh

    2012-03-01

    The problem of resonant Kapitza - Dirac diffraction is solved in Raman - Nath approximation out of familiar Bessel function approximation (applicable in zero and very large resonance detuning cases). It shows new and promising results for the atom optics and atom interferometry if the atomic momentum state has been prepared in a form of discrete Gaussian distribution. Namely, instead of monotonic broadening within the Bessel function approximation, our formula yields in splitting of initial distribution into two identical peaks, whith preserving form, which symmetrically move away from the distribution center for the interaction time. A table-shaped form for the ultimate momentum distribution also is in frame of new distributions. As to relaxation processes, they have only quantitative influence on the pattern of diffraction.

  4. Multi-order nonlinear diffraction in second harmonic generation

    DEFF Research Database (Denmark)

    Saltiel, S. M.; Neshev, D.; Krolikowski, Wieslaw

    We analyze the emission patterns in the process of second harmonic (SH) generation in χ(2) nonlinear gratings and identify for the first time, to the best of our knowledge, the evidence of Raman-Nath type nonlinear diffraction in frequency doubling processes.......We analyze the emission patterns in the process of second harmonic (SH) generation in χ(2) nonlinear gratings and identify for the first time, to the best of our knowledge, the evidence of Raman-Nath type nonlinear diffraction in frequency doubling processes....

  5. Measurement of Wigner function via atomic beam deflection in Raman- Nath regime

    CERN Document Server

    Khosa, A H; Khosa, Ashfaq Hussain

    2002-01-01

    We propose a method for the reconstruction of photon statistics and hence the Wigner function of a quantized cavity field. The method is based on the measurement of momentum distribution of two level atoms after atom- field interaction in Raman-Nath regime. We reconstruct the photon statistics of the cavity field both the cases of resonant and off- resonant atom field interaction.. For the measurement of Wigner function we propose to displace the photon statistics of the cavity field. We successfully reconstruct the Wigner function of the Schrodinger-cat state in a straightforward manner by employing the proposed method without much mathematical manipulation of the experimental data.

  6. Optical Gaussian beam interaction with one-dimensional thermal wave in the Raman-Nath configuration.

    Science.gov (United States)

    Bukowski, Roman J

    2009-03-01

    Optical Gaussian beam interaction with a one-dimensional temperature field in the form of a thermal wave in the Raman-Nath configuration is analyzed. For the description of the Gaussian beam propagation through the nonstationary temperature field the complex geometric optics method was used. The influence of the refractive coefficient modulation by thermal wave on the complex ray phase, path, and amplitude was taken into account. It was assumed that for detection of the modulated Gaussian beam parameters two types of detector can be used: quadrant photodiodes or centroidal photodiodes. The influence of such parameters as the size and position of the Gaussian beam waist, the laser-screen (detector) distance, the thermal wave beam position and width, as well as thermal wave frequency and the distance between the probing optical beam axis and source of thermal waves on the so-called normal signal was taken into account.

  7. Multiorder nonlinear diffraction in frequency doubling processes

    DEFF Research Database (Denmark)

    Saltiel, Solomon M.; Neshev, Dragomir N.; Krolikowski, Wieslaw

    2009-01-01

    We analyze experimentally light scattering from 2 nonlinear gratings and observe two types of second-harmonic frequency-scattering processes. The first process is identified as Raman–Nath type nonlinear diffraction that is explained by applying only transverse phase-matching conditions. The angular...... position of this type of diffraction is defined by the ratio of the second-harmonic wavelength and the grating period. In contrast, the second type of nonlinear scattering process is explained by the longitudinal phase matching only, being insensitive to the nonlinear grating...

  8. Enhanced Nonlinear Optical Effect in Hybrid Liquid Crystal Cells Based on Photonic Crystal

    Science.gov (United States)

    Bugaychuk, Svitlana; Iljin, Andrey; Lytvynenko, Oleg; Tarakhan, Ludmila; Karachevtseva, Lulmila

    2017-07-01

    Nonlinear-optical response of photorefractive hybrid liquid crystal (LC) cells has been studied by means of dynamic holographic technique in two-wave mixing arrangement. The LC cells include nonuniform silicon substrates comprising a micrometer-range photonic crystal. A thin LC layer is set between silicon substrate and a flat glass substrate covered by a transparent (ITO) electrode. A dynamic diffraction grating was induced in the LC volume by the two-wave mixing of laser beams with simultaneous application of DC electric field to the cell. Theoretical model of Raman-Nath self-diffraction was developed. This model allows for calculation of nonlinear optical characteristics in thin samples on the base of two-wave mixing experimental data, and with taking into account light losses on absorption and/or scattering. The hybrid LC cells demonstrate strong nonlinear optical effect, prospective for many applications in electro-optical microsystems, such as SLMs, as well as in multi-channel systems.

  9. Nonlinear diffraction of water waves by offshore stuctures

    Directory of Open Access Journals (Sweden)

    Matiur Rahman

    1986-01-01

    Full Text Available This paper is concerned with a variational formulation of a nonaxisymmetric water wave problem. The full set of equations of motion for the problem in cylindrical polar coordinates is derived. This is followed by a review of the current knowledge on analytical theories and numerical treatments of nonlinear diffraction of water waves by offshore cylindrical structures. A brief discussion is made on water waves incident on a circular harbor with a narrow gap. Special emphasis is given to the resonance phenomenon associated with this problem. A new theoretical analysis is also presented to estimate the wave forces on large conical structures. Second-order (nonlinear effects are included in the calculation of the wave forces on the conical structures. A list of important references is also given.

  10. Nonlinear diffraction effects around a surface-piercing structure

    Energy Technology Data Exchange (ETDEWEB)

    Lalli, F.; Mascio, A. Di; Landrini, M. [Istituto Nazionale per Studi ed Esperienze di Architettura Navale, Rome (Italy)

    1995-12-31

    In the present paper the interaction of a wave system with a submerged or surface piercing body is studied. The wave diffraction caused by a cylinder in finite depth water and by a shoal is been computed and the results are compared with analytical solutions and experimental data. The problem is analyzed numerically in the frame of irrotational incompressible flow hypothesis. Both the linearized and the fully nonlinear mathematical models are studied. The numerical solution is gained by means of a mixed panel-desingularized formulation. An explicit time-marching algorithm updates the wave elevation and the potential at the free surface. In all cases, the numerical simulation mirrors the experimental data. In the case of the diffraction around a cylinder, the simulation confirms and extends the theoretical results of the second order analysis (Kriebel 1990, 1992): the linear model yields a very good estimation of the force amplitude acting on the body, while the wave profiles are poorly predicted when compared with the fully nonlinear simulation and the experimental data.

  11. Diffraction corrections for second harmonic beam fields and effects on the nonlinearity parameter evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyun Jo; Cho, Sung Jong; Nam, Ki Woong; Lee, Jang Hyun [Division of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

    2016-04-15

    The nonlinearity parameter is frequently measured as a sensitive indicator in damaged material characterization or tissue harmonic imaging. Several previous studies have employed the plane wave solution, and ignored the effects of beam diffraction when measuring the non-linearity parameter β. This paper presents a multi-Gaussian beam approach to explicitly derive diffraction corrections for fundamental and second harmonics under quasilinear and paraxial approximation. Their effects on the nonlinearity parameter estimation demonstrate complicated dependence of β on the transmitter-receiver geometries, frequency, and propagation distance. The diffraction effects on the non-linearity parameter estimation are important even in the nearfield region. Experiments are performed to show that improved β values can be obtained by considering the diffraction effects.

  12. Design and Optimisation Strategies of Nonlinear Dynamics for Diffraction Limited Synchrotron Light Source

    CERN Document Server

    Bartolini, R.

    2016-01-01

    This paper introduces the most recent achievements in the control of nonlinear dynamics in electron synchrotron light sources, with special attention to diffraction limited storage rings. Guidelines for the design and optimization of the magnetic lattice are reviewed and discussed.

  13. Nonlinearity management and diffraction management for the stabilization of two-dimensional spatial solitons

    Indian Academy of Sciences (India)

    P A Subha; C P Jisha; V C Kuriakose

    2007-08-01

    The nonlinear Schrödinger equation which governs the dynamics of two-dimensional spatial solitons in Kerr media with periodically varying diffraction and nonlinearity has been analyzed in this paper using variational approach and numerical studies. Analytical expressions for soliton parameters have been derived using variational analysis. Variational equations and partial differential equation have been simulated numerically. Analytical and numerical studies have shown that nonlinearity management and diffraction management stabilize the pulse against decay or collapse providing undisturbed propagation even for larger energies of the incident beam.

  14. Diffraction Interference Induced Superfocusing in Nonlinear Talbot Effect

    Science.gov (United States)

    Liu, Dongmei; Zhang, Yong; Wen, Jianming; Chen, Zhenhua; Wei, Dunzhao; Hu, Xiaopeng; Zhao, Gang; Zhu, S. N.; Xiao, Min

    2014-08-01

    We report a simple, novel subdiffraction method, i.e. diffraction interference induced superfocusing in second-harmonic (SH) Talbot effect, to achieve focusing size of less than λSH/4 (or λpump/8) without involving evanescent waves or subwavelength apertures. By tailoring point spread functions with Fresnel diffraction interference, we observe periodic SH subdiffracted spots over a hundred of micrometers away from the sample. Our demonstration is the first experimental realization of the Toraldo di Francia's proposal pioneered 62 years ago for superresolution imaging.

  15. Electromagnetic wave diffraction by periodic planar metamaterials with nonlinear constituents

    CERN Document Server

    Khardikov, V; Prosvirnin, S; Tuz, V

    2014-01-01

    We present a theory which explains how to achieve an enhancement of nonlinear effects in a thin layer of nonlinear medium by involving a planar periodic structure specially designed to bear a trapped-mode resonant regime. In particular, the possibility of a nonlinear thin metamaterial to produce the bistable response at a relatively low input intensity due to a large quality factor of the trapped-mode resonance is shown. Also a simple design of an all-dielectric low-loss silicon-based planar metamaterial which can provide an extremely sharp resonant reflection and transmission is proposed. The designed metamaterial is envisioned for aggregating with a pumped active medium to achieve an enhancement of quantum dots luminescence and to produce an all-dielectric analog of a 'lasing spaser'.

  16. Nonlinear generalized source method for modeling second-harmonic generation in diffraction gratings

    CERN Document Server

    Weismann, Martin; Panoiu, Nicolae C

    2015-01-01

    We introduce a versatile numerical method for modeling light diffraction in periodically patterned photonic structures containing quadratically nonlinear non-centrosymmetric optical materials. Our approach extends the generalized source method to nonlinear optical interactions by incorporating the contribution of nonlinear polarization sources to the diffracted field in the algorithm. We derive the mathematical formalism underlying the numerical method and introduce the Fourier-factorization suitable for nonlinear calculations. The numerical efficiency and runtime characteristics of the method are investigated in a set of benchmark calculations: the results corresponding to the fundamental frequency are compared to those obtained from a reference method and the beneficial effects of the modified Fourier-factorization rule on the accuracy of the nonlinear computations is demonstrated. In order to illustrate the capabilities of our method, we employ it to demonstrate strong enhancement of second-harmonic genera...

  17. An efficient and accurate method for calculating nonlinear diffraction beam fields

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyun Jo; Cho, Sung Jong; Nam, Ki Woong; Lee, Jang Hyun [Division of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

    2016-04-15

    This study develops an efficient and accurate method for calculating nonlinear diffraction beam fields propagating in fluids or solids. The Westervelt equation and quasilinear theory, from which the integral solutions for the fundamental and second harmonics can be obtained, are first considered. A computationally efficient method is then developed using a multi-Gaussian beam (MGB) model that easily separates the diffraction effects from the plane wave solution. The MGB models provide accurate beam fields when compared with the integral solutions for a number of transmitter-receiver geometries. These models can also serve as fast, powerful modeling tools for many nonlinear acoustics applications, especially in making diffraction corrections for the nonlinearity parameter determination, because of their computational efficiency and accuracy.

  18. A novel method for extracting acoustic nonlinearity parameters with diffraction corrections

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyunjo [Wonkwang University, Iksan (Korea, Republic of); Zhang, Shuzeng; Li, Xiongbing [Central South University, Changsha (China)

    2016-02-15

    A new method for determining the acoustic nonlinearity parameter using a nonlinear data fitting method is proposed. Based on the quasilinear theory of Westervelt's equation, the fundamental and second harmonic beam fields are expressed as a multi-Gaussian beam model that separates the attenuation and diffraction correction terms from the propagating plane waves. A nonlinear least squares curve fitting method is developed to extract the nonlinearity parameter without knowing the attenuation coefficients of the material being tested. The nonlinearity parameter of water is determined using the proposed method, and the result agrees well with the literature value. The attenuation coefficients of the fundamental and the second harmonic are also extracted and discussed.

  19. Third-order nonlinear and linear time-dependent dynamical diffraction of X-rays in crystals.

    Science.gov (United States)

    Balyan, Minas K

    2016-07-01

    For the first time the third-order nonlinear time-dependent Takagi's equations of X-rays in crystals are obtained and investigated. The third-order nonlinear and linear time-dependent dynamical diffraction of X-rays spatially restricted in the diffraction plane pulses in crystals is investigated theoretically. A method of solving the linear and the third-order nonlinear time-dependent Takagi's equations is proposed. Based on this method, results of analytical and numerical calculations for both linear and nonlinear diffraction cases are presented and compared.

  20. Nonlinear focusing of ultrasonic waves by an axisymmetric diffraction grating embedded in water

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, N.; Picó, R. [Instituto de Investigación para la Gestión Integrada de zonas Costeras, Universitat Politècnica de València, Paranimf 1, 46730 Grao de Gandia, València (Spain); Romero-García, V. [LUNAM Université, Université du Maine, LAUM UMR CNRS 6613, Av. O. Messiaen, 72085 Le Mans (France); Garcia-Raffi, L. M. [Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València, Camino de Vera s/n, 46022 València (Spain); Staliunas, K. [ICREA, Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Colom, 11, E-08222 Terrassa, Barcelona (Spain)

    2015-11-16

    We report the nonlinear focusing of ultrasonic waves by an axisymmetric diffraction grating immersed in water. In the linear regime, the system presents high focal gain (32 dB), with a narrow beam-width and intense side lobes as it is common in focusing by Fresnel-like lenses. Activating the nonlinearity of the host medium by using high amplitude incident waves, the focusing properties of the lens dramatically change. Theoretical predictions show that the focal gain of the system extraordinary increases in the strongly nonlinear regime (Mach number of 6.1 × 10{sup −4}). Particularly, the harmonic generation is locally activated at the focal spot, and the second harmonic beam is characterized by strongly reduced side-lobes and an excellent beam profile as experiments show in agreement with theory. The results can motivate applications in medical therapy or second harmonic imaging.

  1. Diffraction efficiency of plasmonic gratings fabricated by electron beam lithography using a silver halide film

    Science.gov (United States)

    Sudheer, Porwal, S.; Bhartiya, S.; Rao, B. T.; Tiwari, P.; Srivastava, Himanshu; Sharma, T. K.; Rai, V. N.; Srivastava, A. K.; Naik, P. A.

    2016-07-01

    The silver nanoparticle surface relief gratings of ˜10 μm period are fabricated using electron beam lithography on the silver halide film substrate. Morphological characterization of the gratings shows that the period, the shape, and the relief depth in the gratings are mainly dependent on the number of lines per frame, the spot size, and the accelerating voltage of electron beam raster in the SEM. Optical absorption of the silver nanoparticle gratings provides a broad localized surface plasmon resonance peak in the visible region, whereas the intensity of the peaks depends on the number density of silver nanoparticles in the gratings. The maximum efficiency of ˜7.2% for first order diffraction is observed for the grating fabricated at 15 keV. The efficiency is peaking at 560 nm with ˜380 nm bandwidth. The measured profiles of the diffraction efficiency for the gratings are found in close agreement with the Raman-Nath diffraction theory. This technique provides a simple and efficient method for the fabrication of plasmonic nanoparticle grating structures with high diffraction efficiency having broad wavelength tuning.

  2. Diffraction efficiency of plasmonic gratings fabricated by electron beam lithography using a silver halide film

    Energy Technology Data Exchange (ETDEWEB)

    Sudheer,, E-mail: sudheer@rrcat.gov.in, E-mail: sudheer.rrcat@gmail.com; Tiwari, P.; Srivastava, Himanshu; Rai, V. N.; Srivastava, A. K.; Naik, P. A. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Porwal, S. [Solid State Lasers Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Bhartiya, S. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Laser Materials Development and Device Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Rao, B. T. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Sharma, T. K. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Solid State Lasers Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India)

    2016-07-28

    The silver nanoparticle surface relief gratings of ∼10 μm period are fabricated using electron beam lithography on the silver halide film substrate. Morphological characterization of the gratings shows that the period, the shape, and the relief depth in the gratings are mainly dependent on the number of lines per frame, the spot size, and the accelerating voltage of electron beam raster in the SEM. Optical absorption of the silver nanoparticle gratings provides a broad localized surface plasmon resonance peak in the visible region, whereas the intensity of the peaks depends on the number density of silver nanoparticles in the gratings. The maximum efficiency of ∼7.2% for first order diffraction is observed for the grating fabricated at 15 keV. The efficiency is peaking at 560 nm with ∼380 nm bandwidth. The measured profiles of the diffraction efficiency for the gratings are found in close agreement with the Raman-Nath diffraction theory. This technique provides a simple and efficient method for the fabrication of plasmonic nanoparticle grating structures with high diffraction efficiency having broad wavelength tuning.

  3. Sub-diffraction imaging on standard microscopes through photobleaching microscopy with non-linear processing.

    Science.gov (United States)

    Munck, Sebastian; Miskiewicz, Katarzyna; Sannerud, Ragna; Menchon, Silvia A; Jose, Liya; Heintzmann, Rainer; Verstreken, Patrik; Annaert, Wim

    2012-05-01

    Visualization of organelles and molecules at nanometer resolution is revolutionizing the biological sciences. However, such technology is still limited for many cell biologists. We present here a novel approach using photobleaching microscopy with non-linear processing (PiMP) for sub-diffraction imaging. Bleaching of fluorophores both within the single-molecule regime and beyond allows visualization of stochastic representations of sub-populations of fluorophores by imaging the same region over time. Our method is based on enhancing the probable positions of the fluorophores underlying the images. The random nature of the bleached fluorophores is assessed by calculating the deviation of the local actual bleached fluorescence intensity to the average bleach expectation as given by the overall decay of intensity. Subtracting measured from estimated decay images yields differential images. Non-linear enhancement of maxima in these diffraction-limited differential images approximates the positions of the underlying structure. Summing many such processed differential images yields a super-resolution PiMP image. PiMP allows multi-color, three-dimensional sub-diffraction imaging of cells and tissues using common fluorophores and can be implemented on standard wide-field or confocal systems.

  4. Parametric wave interaction in quadratic crystal with randomized distribution of ferroelectric domains

    CERN Document Server

    Kalinowski, Ksawery; Łukasiewicz, Tadeusz; Świrkowicz, Marek; Sheng, Yan; Krolikowski, Wieslaw

    2012-01-01

    We study the parametric wave interaction in qua- dratic nonlinear media with randomized distribution of the ferroelectric domains. In particular, we discuss properties of second and cascaded third harmonic generation. We derive analytical formulas describing emission properties of the second and third harmonics in the presence of domain disorder and show that the latter process is governed by the characteristics of the constituent processes, i.e. second harmonic generation and sum frequency mixing. We demonstrate the role of randomness on various second and third harmonic generation regimes such as Raman-Nath and \\v{C}erenkov nonlinear diffraction. We show that the randomness-induced incoherence in the wave interaction leads to deterioration of conversion efficiency and angular spreading of harmonic generated in the processes relying on transverse phase matching such as Raman-Nath. On the other hand forward and \\v{C}erenkov frequency generation are basically insensitive to the domain randomness.

  5. Functions of diffraction correction and analytical solutions in nonlinear acoustic measurement

    CERN Document Server

    Alliès, Laurent; Nadi, M

    2008-01-01

    This paper presents an analytical formulation for correcting the diffraction associated to the second harmonic of an acoustic wave, more compact than that usually used. This new formulation, resulting from an approximation of the correction applied to fundamental, makes it possible to obtain simple solutions for the second harmonic of the average acoustic pressure, but sufficiently precise for measuring the parameter of nonlinearity B/A in a finite amplitude method. Comparison with other expressions requiring numerical integration, show the solutions are precise in the nearfield.

  6. Diffractive optics based four-wave, six-wave, ..., nu-wave nonlinear spectroscopy.

    Science.gov (United States)

    Miller, R J Dwayne; Paarmann, Alexander; Prokhorenko, Valentyn I

    2009-09-15

    A detailed understanding of chemical processes requires information about both structure and dynamics. By definition, a reaction involves nonstationary states and is a dynamic process. Structure describes the atomic positions at global minima in the nuclear potential energy surface. Dynamics are related to the anharmonicities in this potential that couple different minima and lead to changes in atomic positions (reactions) and correlations. Studies of molecular dynamics can be configured to directly access information on the anharmonic interactions that lead to chemical reactions and are as central to chemistry as structural information. In this regard, nonlinear spectroscopies have distinct advantages over more conventional linear spectroscopies. Because of this potential, nonlinear spectroscopies could eventually attain a comparable level of importance for studying dynamics on the relevant time scales to barrier crossings and reactive processes as NMR has for determining structure. Despite this potential, nonlinear spectroscopy has not attained the same degree of utility as linear spectroscopy largely because nonlinear studies are more technically challenging. For example, unlike the linear spectrometers that exist in almost all chemistry departments, there are no "black box" four-wave mixing spectrometers. This Account describes recent advances in the application of diffractive optics (DOs) to nonlinear spectroscopy, which reduces the complexity level of this technology to be closer to that of linear spectroscopy. The combination of recent advances in femtosecond laser technology and this single optic approach could bring this form of spectroscopy out of the exclusive realm of specialists and into the general user community. However, the real driving force for this research is the pursuit of higher sensitivity limits, which would enable new forms of nonlinear spectroscopy. This Account chronicles the research that has now extended nonlinear spectroscopy to six

  7. Fast spatial beam shaping by acousto-optic diffraction for 3D non-linear microscopy.

    Science.gov (United States)

    Akemann, Walther; Léger, Jean-François; Ventalon, Cathie; Mathieu, Benjamin; Dieudonné, Stéphane; Bourdieu, Laurent

    2015-11-01

    Acousto-optic deflection (AOD) devices offer unprecedented fast control of the entire spatial structure of light beams, most notably their phase. AOD light modulation of ultra-short laser pulses, however, is not straightforward to implement because of intrinsic chromatic dispersion and non-stationarity of acousto-optic diffraction. While schemes exist to compensate chromatic dispersion, non-stationarity remains an obstacle. In this work we demonstrate an efficient AOD light modulator for stable phase modulation using time-locked generation of frequency-modulated acoustic waves at the full repetition rate of a high power laser pulse amplifier of 80 kHz. We establish the non-local relationship between the optical phase and the generating acoustic frequency function and verify the system for temporal stability, phase accuracy and generation of non-linear two-dimensional phase functions.

  8. Optical multiple-image encryption in diffractive-imaging-based scheme using spectral fusion and nonlinear operation.

    Science.gov (United States)

    Qin, Yi; Gong, Qiong; Wang, Zhipeng; Wang, Hongjuan

    2016-11-14

    We report a new method for multiple-image encryption in diffractive-imaging-based encryption (DIBE) scheme. The discrete cosine transformation (DCT) spectra of the primary images are extracted, compacted and then nonlinear-transformed before being sent to the DIBE, where they are encoded into a single intensity pattern. With the help of a suggested phase retrieval algorithm, the original images can be recovered with high quality. Furthermore, due to the introduction of the nonlinear operation, the proposal is demonstrated to be robust to the currently available cryptographic attacks. The proposal probes a new way for multiple-image encryption in DIBE, and its effectiveness and feasibility have been supported by numerical simulations.

  9. Optical correlation using isotropic and anisotropic self diffraction using photorefractive material

    Science.gov (United States)

    Buranasiri, Prathan

    generated by using one incident beam and by using the contrapropagating PC reflected at the surface of incidence as the second beam. By using this scheme, which we call single-beam holography, we have found that CODAS is generated by energy transfer through both first order and higher order gratings. Gratings formed during single-beam holography have been interrogated using different reading wavelengths for both Bragg and anisotropic Raman-Nath regimes. The application of self-diffracted higher orders to image correlation using amplitude objects has been investigated, and its application to phase objects will be more extensively pursued in the future.

  10. Generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser in a cascade of nonlinear crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Jensen, Ole Bjarlin; Sumpf, Bernd

    2014-01-01

    -focusing and dispersion compensating optics between the two nonlinear crystals. In the low-power limit, such a cascade of two crystals has the theoretical potential for generation of four times as much power as a single crystal without adding significantly to the complexity of the system. The experimentally achieved...... frequency conversion of infrared tapered diode lasers. Here, we describe the generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser, itself yielding 10 W at 1063 nm. This SHG is performed in single pass through a cascade of two PPMgO:LN crystals with re...... power of 3.5 W corresponds to a power enhancement greater than 2 compared to SHG in each of the crystals individually and is the highest visible output power generated by frequency conversion of a single diode laser. Such laser sources provide the necessary pump power for biophotonics applications...

  11. High-pressure crystal structure of the non-linear optical compound BiB(3)O(6) from two-dimensional powder diffraction data.

    Science.gov (United States)

    Dinnebier, R E; Hinrichsen, B; Lennie, A; Jansen, M

    2009-02-01

    Our recently proposed method for automatic detection, calibration and evaluation of Debye-Scherrer ellipses using pattern-recognition techniques and advanced signal filtering was applied to the two-dimensional powder diffraction data of the non-ferroelectric, non-centrosymmetric non-linear optical (NLO) compound alpha-BiB(3)O(6) as a function of pressure. At ambient conditions, alpha-BiB(3)O(6) crystallizes in the space group C2 (phase I). In the pressure range between P = 6.09 and 6.86 GPa, it exhibits a first-order phase transition into a structure with the space group C1 (P1) [phase II at P = 8.34 GPa: a = 7.4781 (6), b = 3.9340 (4), c = 6.2321 (6) A, alpha = 93.73 (1), beta = 102.93 (1), gamma = 90.76 (1) degrees , and V = 178.24 (3) A(3)]. Non-linear compression behaviour over the entire pressure range is observed, which can be described by two Vinet relations in the ranges from P = 0.0 to 6.09 GPa, and from P = 6.86 to 11.6 GPa. The extrapolated bulk moduli of the high-pressure phases were determined to be K(0) = 38 (1) GPa for phase I, and K(0) = 114 (10) GPa for phase II. The crystal structures of both phases were refined against X-ray powder diffraction data measured at several pressures between 0.0 and 11.6 GPa. The structural phase transition of alpha-BiB(3)O(6) is mainly characterized by a reorientation of the [BO(3)](3-) triangles, the [BO(4)](5-) tetrahedra and the lone electron pair which is localized at Bi(3+), in order to optimize crystal packing.

  12. Molecular origins of nonlinear optical activity in zinc tris(thiourea)sulfate revealed by high-resolution x-ray diffraction data and ab initio calculations

    Science.gov (United States)

    Cole, Jacqueline M.; Hickstein, Daniel D.

    2013-11-01

    Structure-property relationships are established in the nonlinear optical (NLO) material, zinc tris(thiourea)sulfate (ZTS), via an experimental charge-density study, x-ray constrained wave-function refinement, and quantum-mechanical calculations. The molecular charge-transfer characteristics of ZTS, that are important for NLO activity, are topologically analyzed via a multipolar refinement of high-resolution x-ray diffraction data, which is supported by neutron diffraction measurements. The extent to which each chemical bond is ionic or covalent in nature is categorized by Laplacian-based bonding classifiers of the electron density; these include bond ellipticities, energy densities, and the local source function. Correspondingly, the NLO origins of ZTS are judged to best resemble those of organic NLO materials. The molecular dipole moment, μi, and (hyper)polarizability coefficients, αij and βijk, are calculated from the experimental diffraction data using the x-ray constrained wave-function method. Complementary gas-phase ab initio quantum-mechanical calculations of μi, αij, and βijk offer a supporting comparison. When taken alone, the experimental charge-density analysis does not fare well in deriving μi, αij, or βijk, which is not entirely surprising given that the associated calculations are only generally valid for organic molecules. However, by refining the x-ray data within the constrained wave-function method, the evaluations of μi, αij, and βijk are shown to agree very well with those from ab initio calculations and show remarkable normalization to experimental refractive index measurements. The small differences observed between ab initio and x-ray constrained wave-function refinement results can be related directly to gas- versus solid-state phase differences. μi is found to be 28.3 Debye (gas phase) and 29.7 Debye (solid state) while βijk coefficients are not only significant but are also markedly three dimensional in form. Accordingly

  13. 5.5 W of Diffraction-Limited Green Light Generated by SFG of Tapered Diode Lasers in a Cascade of Nonlinear Crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Jensen, Ole Bjarlin; Andersen, Peter Eskil

    2015-01-01

    Diode-based high power visible lasers are perfect pump sources for, e.g., titaniumsapphire lasers. The combination of favorable scaling laws in both SFG and cascading of nonlinear crystals allows access to unprecedented powers in diode-based systems....

  14. Generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser in a cascade of nonlinear crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Jensen, Ole Bjarlin; Sumpf, Bernd;

    2014-01-01

    Many applications, e.g., within biomedicine stand to benefit greatly from the development of diode laser-based multi- Watt efficient compact green laser sources. The low power of existing diode lasers in the green area (about 100 mW) means that the most promising approach remains nonlinear......, such as optical coherence tomography or multimodal imaging devices, e.g., FTCARS-OCT, based on a strongly pumped ultrafast Ti:Sapphire laser....

  15. Diffraction to De-Diffraction

    CERN Document Server

    Tamari, V F

    2003-01-01

    De-diffraction (DD), a new procedure to totally cancel diffraction effects from wave-fields is presented, whereby the full field from an aperture is utilized and a truncated geometrical field is obtained, allowing infinitely sharp focusing and non-diverging beams. This is done by reversing a diffracted wave-fields' direction. The method is derived from the wave equation and demonstrated in the case of Kirchhoff's integral. An elementary bow-wavelet is described and the DD process is related to quantum and relativity theories.

  16. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  17. X-Ray Diffraction Analysis Program

    Science.gov (United States)

    Wiedemann, K. E.; Unnam, J.; Naidu, S. V. N.; Houska, C. R.

    1986-01-01

    SOPAD separates overlapping peaks and analyzes derivatives of X-ray diffraction data. SOPAD helps analyst get most information out of available diffraction data. SOPAD uses Marquardt-type nonlinear regression routine to refine initial estimates of individual peak positions, intensities, shapes, and half-widths.

  18. Diffractive Physics

    CERN Document Server

    Martin, A D; Khoze, V A; Krauss, F; Ryskin, M G; Zapp, K

    2012-01-01

    `Soft' high-energy interactions are clearly important in pp collisions. Indeed, these events are dominant by many orders of magnitude, and about 40% are of diffractive origin; that is, due to elastic scattering or proton dissociation. Moreover, soft interactions unavoidably give an underlying component to the rare `hard' events, from which we hope to extract new physics. Here, we discuss how to quantify this contamination. First we present a brief introduction to diffraction. We emphasize the different treatment required for proton dissociation into low- and high-mass systems; the former requiring a multichannel eikonal approach, and the latter the computation of triple-Pomeron diagrams with multi-Pomeron corrections. Then we give an overview of the Pomeron, and explain how the QCD (BFKL-type) Pomeron is the natural object to continue from the `hard' to the `soft' domain. In this way we can obtain a partonic description of soft interactions. We introduce the so-called KMR model, based on this partonic approac...

  19. Diffraction from an edge in a self-focusing medium.

    Science.gov (United States)

    Wan, Wenjie; Dylov, Dmitry V; Barsi, Christopher; Fleischer, Jason W

    2010-08-15

    We experimentally demonstrate diffraction from a straight edge in a medium with self-focusing nonlinearity. Diffraction into the shadow region is suppressed with increasing nonlinearity, but mode coupling leads to excitations and traveling waves on the high-intensity side. Theoretically, we interpret these modulations as spatially dispersive shock waves with negative pressure.

  20. Pyramid diffraction in parity-time-symmetric optical lattices

    CERN Document Server

    Nixon, Sean

    2013-01-01

    Nonlinear dynamics of wave packets in two-dimensional parity-time-symmetric optical lattices near the phase-transition point are analytically studied. A novel fourth-order equation is derived for the envelope of these wave packets. A pyramid diffraction pattern is demonstrated in both the linear and nonlinear regimes. Blow-up is also possible in the nonlinear regime for both focusing and defocusing nonlinearities.

  1. Genetic Synthesis of the Diffraction Profile

    Directory of Open Access Journals (Sweden)

    Stanislav Jurecka

    2004-01-01

    Full Text Available In this paper we describe theoretical synthesis of the x-ray diffraction line profile as a superposition of the spectral components Ka1 and Ka2 optimized to the experimental data by the genetic algorithm and nonlinear optimization methods 'Nelder-Mead downhill simplex' and Levenberg-Marquardt method. Such combination of global and local optimization methods results in a mathematical model of the diffraction profile, providing reliable determininig of diffraction line characteristics for the material structure properties study. Experimetal results of the optimization preocedures are given too.

  2. Anomalous diffraction in hyperbolic materials

    CERN Document Server

    Alberucci, Alessandro; Boardman, Allan D; Assanto, Gaetano

    2016-01-01

    We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, spatial analogue of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.

  3. Anomalous diffraction in hyperbolic materials

    Science.gov (United States)

    Alberucci, Alessandro; Jisha, Chandroth P.; Boardman, Allan D.; Assanto, Gaetano

    2016-09-01

    We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, i.e., spatial analog of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.

  4. The Diffraction Response Interpolation Method

    DEFF Research Database (Denmark)

    Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Pedersen, Peder C.

    1998-01-01

    medium, is presented. The DRIM is based on the velocity potential impulseresponse method, adapted to pulse-echo applications by the use of acoustical reciprocity. Specifically, the DRIM operates bydividing the reflector surface into planar elements, finding the diffraction response at the corners...... of the elements, calculating theresponse integrated over the surface element by time-domain convolutions with analytically determined filters, and summing theresponses from the individual surface elements. As the method is based on linearity, effects such as shadowing, higher-orderdiffraction, nonlinear...

  5. Diffraction manipulation by four-wave mixing.

    Science.gov (United States)

    Katzir, Itay; Ron, Amiram; Firstenberg, Ofer

    2015-03-09

    We suggest a scheme to manipulate paraxial diffraction by utilizing the dependency of a four-wave mixing process on the relative angle between the light fields. A microscopic model for four-wave mixing in a Λ-type level structure is introduced and compared to recent experimental data. We show that images with feature size as low as 10 μm can propagate with very little or even negative diffraction. The mechanism is completely different from that conserving the shape of spatial solitons in nonlinear media, as here diffraction is suppressed for arbitrary spatial profiles. At the same time, the gain inherent to the nonlinear process prevents loss and allows for operating at high optical depths. Our scheme does not rely on atomic motion and is thus applicable to both gaseous and solid media.

  6. Diffraction coherence in optics

    CERN Document Server

    Françon, M; Green, L L

    2013-01-01

    Diffraction: Coherence in Optics presents a detailed account of the course on Fraunhofer diffraction phenomena, studied at the Faculty of Science in Paris. The publication first elaborates on Huygens' principle and diffraction phenomena for a monochromatic point source and diffraction by an aperture of simple form. Discussions focus on diffraction at infinity and at a finite distance, simplified expressions for the field, calculation of the path difference, diffraction by a rectangular aperture, narrow slit, and circular aperture, and distribution of luminous flux in the airy spot. The book th

  7. X-Ray Diffraction.

    Science.gov (United States)

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  8. X-Ray Diffraction.

    Science.gov (United States)

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  9. Diffractive production of mesons

    CERN Document Server

    Schicker, R

    2014-01-01

    The interest in the study of diffractive meson production is discussed. The description of diffraction within Regge phenomenology is presented, and the QCD-based understanding of diffractive processes is given. Central production is reviewed, and the corresponding main results from the COMPASS experiment and from the experiments at the ISR, RHIC, TEVATRON and LHC collider are summarised.

  10. Robustness via Diffractal Architectures

    CERN Document Server

    Moocarme, Matthew

    2015-01-01

    When plane waves diffract through fractal-patterned apertures, the resulting far-field profiles or diffractals also exhibit iterated, self-similar features. Here we show that this specific architecture enables robust signal processing and spatial multiplexing: arbitrary parts of a diffractal contain sufficient information to recreate the entire original sparse signal.

  11. Diffractive production of mesons

    Directory of Open Access Journals (Sweden)

    Schicker Rainer

    2014-01-01

    Full Text Available The interest in the study of diffractive meson production is discussed. The description of diffraction within Regge phenomenology is presented, and the QCD-based understanding of diffractive processes is given. Central production is reviewed, and the corresponding main results from the COMPASS experiment and from the experiments at the ISR, RHIC, TEVATRON and LHC collider are summarised.

  12. Tunable nonlinear beam defocusing in infiltrated photonic crystal fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis H; Neshev, Dragomir N.;

    2007-01-01

    We demonstrate a novel experimental platform for discrete nonlinear optics based on infiltrated photonic crystal fibers. We observe tunable discrete diffraction and nonlinear self-defocusing, and apply the effects to realize a compact all-optical power limiter....

  13. X-ray photoelectron spectroscopy, high-resolution X-ray diffraction and refractive index analyses of Ti-doped lithium niobate (Ti:LiNbO3) nonlinear optical single crystal

    Indian Academy of Sciences (India)

    P Kumar; S Moorthy Babu; S Perero; Rajamaniccam L Sai; I Bhaumik; S Ganesamoorthy; A K Karnal

    2010-11-01

    Congruent LiNbO3 single crystals with Ti ion dopants (2 and 5 mol%) were successfully grown by Czochralski technique in the automatic diameter control facility. As-grown crystal boules were oriented into (0 0 1) direction cut and optically polished for all measurements. Influence of Ti-ion incorporation into LiNbO3 was studied by core level XPS analysis. Powder X-ray diffraction studies were carried out on doped lithium niobate for phase identification. High-resolution X-ray diffraction technique was used to study the crystalline quality through full-width at half-maximum values. The refractive index values are more for doped samples than for pure sample as determined by prism coupling technique with different laser sources.

  14. Fiber diffraction without fibers.

    Science.gov (United States)

    Poon, H-C; Schwander, P; Uddin, M; Saldin, D K

    2013-06-28

    Postprocessing of diffraction patterns of completely randomly oriented helical particles, as measured, for example, in so-called "diffract-and-destroy" experiments with an x-ray free electron laser can yield "fiber diffraction" patterns expected of fibrous bundles of the particles. This will allow "single-axis alignment" to be performed computationally, thus obviating the need to do this by experimental means such as forming fibers and laser or flow alignment. The structure of such particles may then be found by either iterative phasing methods or standard methods of fiber diffraction.

  15. Modern diffraction methods

    CERN Document Server

    Mittemeijer, E J

    2013-01-01

    The role of diffraction methods for the solid-state sciences has been pivotal to determining the (micro)structure of a material. Particularly, the expanding activities in materials science have led to the development of new methods for analysis by diffraction. This book offers an authoritative overview of the new developments in the field of analysis of matter by (in particular X-ray, electron and neutron) diffraction. It is composed of chapters written by leading experts on 'modern diffraction methods'. The focus in the various chapters of this book is on the current forefront of research on

  16. Robustness of Cantor diffractals.

    Science.gov (United States)

    Verma, Rupesh; Sharma, Manoj Kumar; Banerjee, Varsha; Senthilkumaran, Paramasivam

    2013-04-08

    Diffractals are electromagnetic waves diffracted by a fractal aperture. In an earlier paper, we reported an important property of Cantor diffractals, that of redundancy [R. Verma et. al., Opt. Express 20, 8250 (2012)]. In this paper, we report another important property, that of robustness. The question we address is: How much disorder in the Cantor grating can be accommodated by diffractals to continue to yield faithfully its fractal dimension and generator? This answer is of consequence in a number of physical problems involving fractal architecture.

  17. Surprises in aperiodic diffraction

    CERN Document Server

    Baake, Michael

    2009-01-01

    Mathematical diffraction theory is concerned with the diffraction image of a given structure and the corresponding inverse problem of structure determination. In recent years, the understanding of systems with continuous and mixed spectra has improved considerably. Moreover, the phenomenon of homometry shows various unexpected new facets. Here, we report on some of the recent results in an exemplary and informal fashion.

  18. Analyzing algorithms for nonlinear and spatially nonuniform phase shifts in the liquid crystal point diffraction interferometer. 1998 summer research program for high school juniors at the University of Rochester`s Laboratory for Laser Energetics: Student research reports

    Energy Technology Data Exchange (ETDEWEB)

    Jain, N. [Pittsford Sutherland High School, NY (United States)

    1999-03-01

    Phase-shifting interferometry has many advantages, and the phase shifting nature of the Liquid Crystal Point Diffraction Interferometer (LCPDI) promises to provide significant improvement over other current OMEGA wavefront sensors. However, while phase-shifting capabilities improve its accuracy as an interferometer, phase-shifting itself introduces errors. Phase-shifting algorithms are designed to eliminate certain types of phase-shift errors, and it is important to chose an algorithm that is best suited for use with the LCPDI. Using polarization microscopy, the authors have observed a correlation between LC alignment around the microsphere and fringe behavior. After designing a procedure to compare phase-shifting algorithms, they were able to predict the accuracy of two particular algorithms through computer modeling of device-specific phase shift-errors.

  19. Non-diffractive waves

    CERN Document Server

    Hernandez-Figueroa, Hugo E; Recami, Erasmo

    2013-01-01

    This continuation and extension of the successful book ""Localized Waves"" by the same editors brings together leading researchers in non-diffractive waves to cover the most important results in their field and as such is the first to present the current state.The well-balanced presentation of theory and experiments guides readers through the background of different types of non-diffractive waves, their generation, propagation, and possible applications. The authors include a historical account of the development of the field, and cover different types of non-diffractive waves, including Airy

  20. Coherent diffractive {rho} production

    Energy Technology Data Exchange (ETDEWEB)

    Hyett, N.M.; Tovey, S.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1995-12-31

    Coherent diffractive {rho} production by neutrinos occurs at low four-momentum transfer and high energy transfer. These interactions are generally understood to occur via the coupling of the weak charged current to the vector meson, which scatters diffractively from the target nucleus. Since coherent events are those in which the nucleus interacts as a whole, ie without breakup, and with small recoil energy, these events have a very sharp |t|-distribution. This presentation deals mostly with the Monte Carlo simulation of the coherent diffractive production of the {rho} production and in particular with the reconstruction algorithm (description and efficiency) and the |t| distribution. 4 refs., 1 fig.

  1. Optical generation of non-diffracting beams via photorefractive holography

    CERN Document Server

    Vieira, Tarcio A; Gesualdi, Marcos R R; Zamboni-Rached, Michel

    2015-01-01

    This work presents, for the first time the optical generation of non-diffracting beams via photorefractive holography. Optical generation of non-diffracting beams using conventional optics components is difficult and, in some instances, unfeasible, as it is wave fields given by superposition of non-diffracting beams. It is known that computer generated holograms and spatial light modulators (SLMs) successfully generate such beams. With photorefractive holography technique, the hologram of a non-diffracting beam is constructed (recorded) and reconstructed (reading) optically in a nonlinear photorefractive medium. The experimental realization of a non-diffracting beam was made in a photorefractive holography setup using a photorefractive Bi12SiO20 (BSO) crystal as the holographic recording medium, where the non-diffracting beams, the Bessel beam arrays and superposition of co-propagating Bessel beams (Frozen Waves) were obtained experimentally. The experimental results are in agreement with the theoretically pr...

  2. Physics issues in diffraction limited storage ring design

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; BAI ZhengHe; GAO WeiWei; FENG GuangYao; LI WeiMin; WANG Lin; HE DuoHui

    2012-01-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources,whose main characteristics are higher brilliance,better transverse coherence and better stability.The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance.Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design.As an example of application,partial physical design of HALS (Hefei Advanced Light Source),which is a diffraction limited VUV and soft X-ray light source,was introduced.Severe emittance growth due to the Intra Beam Scattering effect,which is the main obstacle to achieve ultra low emittance,was estimated quantitatively and possible cures were discussed.It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  3. Physics issues in diffraction limited storage ring design

    Science.gov (United States)

    Fan, Wei; Bai, ZhengHe; Gao, WeiWei; Feng, GuangYao; Li, WeiMin; Wang, Lin; He, DuoHui

    2012-05-01

    Diffraction limited electron storage ring is considered a promising candidate for future light sources, whose main characteristics are higher brilliance, better transverse coherence and better stability. The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance. Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design. As an example of application, partial physical design of HALS (Hefei Advanced Light Source), which is a diffraction limited VUV and soft X-ray light source, was introduced. Severe emittance growth due to the Intra Beam Scattering effect, which is the main obstacle to achieve ultra low emittance, was estimated quantitatively and possible cures were discussed. It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

  4. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas

    1996-01-01

    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  5. Nonlinear supratransmission

    Energy Technology Data Exchange (ETDEWEB)

    Geniet, F; Leon, J [Physique Mathematique et Theorique, CNRS-UMR 5825, 34095 Montpellier (France)

    2003-05-07

    A nonlinear system possessing a natural forbidden band gap can transmit energy of a signal with a frequency in the gap, as recently shown for a nonlinear chain of coupled pendulums (Geniet and Leon 2002 Phys. Rev. Lett. 89 134102). This process of nonlinear supratransmission, occurring at a threshold that is exactly predictable in many cases, is shown to have a simple experimental realization with a mechanical chain of pendulums coupled by a coil spring. It is then analysed in more detail. First we go to different (nonintegrable) systems which do sustain nonlinear supratransmission. Then a Josephson transmission line (a one-dimensional array of short Josephson junctions coupled through superconducting wires) is shown to also sustain nonlinear supratransmission, though being related to a different class of boundary conditions, and despite the presence of damping, finiteness, and discreteness. Finally, the mechanism at the origin of nonlinear supratransmission is found to be a nonlinear instability, and this is briefly discussed here.

  6. Practical Nonlinearities

    Science.gov (United States)

    2016-07-01

    Advanced Research Projects Agency (DARPA) Dynamics-Enabled Frequency Sources (DEFYS) program is focused on the convergence of nonlinear dynamics and...Early work in this program has shown that nonlinear dynamics can provide performance advantages. However, the pathway from initial results to...dependent nonlinear stiffness observed in these devices. This work is ongoing, and will continue through the final period of this program . Reference 9

  7. Calculating cellulose diffraction patterns

    Science.gov (United States)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  8. Diffract, then destroy

    Science.gov (United States)

    Ball, Philip

    2016-09-01

    A new implementation of X-ray diffraction using free-electron lasers can take snapshots of biological molecules that are inaccessible via X-ray crystallography. As Philip Ball reports, the technique can even be used to create stop-motion films of dynamic molecular processes

  9. DIFFRACTION FROM MODEL CRYSTALS

    Science.gov (United States)

    Although calculating X-ray diffraction patterns from atomic coordinates of a crystal structure is a widely available capability, calculation from non-periodic arrays of atoms has not been widely applied to cellulose. Non-periodic arrays result from modeling studies that, even though started with at...

  10. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  11. Nonlinear Science

    CERN Document Server

    Yoshida, Zensho

    2010-01-01

    This book gives a general, basic understanding of the mathematical structure "nonlinearity" that lies in the depths of complex systems. Analyzing the heterogeneity that the prefix "non" represents with respect to notions such as the linear space, integrability and scale hierarchy, "nonlinear science" is explained as a challenge of deconstruction of the modern sciences. This book is not a technical guide to teach mathematical tools of nonlinear analysis, nor a zoology of so-called nonlinear phenomena. By critically analyzing the structure of linear theories, and cl

  12. Nonlinear analysis

    CERN Document Server

    Nanda, Sudarsan

    2013-01-01

    "Nonlinear analysis" presents recent developments in calculus in Banach space, convex sets, convex functions, best approximation, fixed point theorems, nonlinear operators, variational inequality, complementary problem and semi-inner-product spaces. Nonlinear Analysis has become important and useful in the present days because many real world problems are nonlinear, nonconvex and nonsmooth in nature. Although basic concepts have been presented here but many results presented have not appeared in any book till now. The book could be used as a text for graduate students and also it will be useful for researchers working in this field.

  13. Simulation of non-linear ultrasound fields

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Fox, Paul D.; Wilhjelm, Jens E.

    2002-01-01

    An approach for simulating non-linear ultrasound imaging using Field II has been implemented using the operator splitting approach, where diffraction, attenuation, and non-linear propagation can be handled individually. The method uses the Earnshaw/Poisson solution to Burgcrs' equation for the non......-linear ultrasound imaging in 3D using filters or pulse inversion for any kind of transducer, focusing, apodization, pulse emission and scattering phantom. This is done by first simulating the non-linear emitted field and assuming that the scattered field is weak and linear. The received signal is then the spatial...

  14. Model of anisotropic nonlinearity in self-defocusing photorefractive media.

    Science.gov (United States)

    Barsi, C; Fleischer, J W

    2015-09-21

    We develop a phenomenological model of anisotropy in self-defocusing photorefractive crystals. In addition to an independent term due to nonlinear susceptibility, we introduce a nonlinear, non-separable correction to the spectral diffraction operator. The model successfully describes the crossover between photovoltaic and photorefractive responses and the spatially dispersive shock wave behavior of a nonlinearly spreading Gaussian input beam. It should prove useful for characterizing internal charge dynamics in complex materials and for accurate image reconstruction through nonlinear media.

  15. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    Energy Technology Data Exchange (ETDEWEB)

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  16. Polychromatic diffraction contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    King, A., E-mail: king@synchrotron-soleil.fr [Synchrotron SOLEIL, Gif-sur-Yvette 91192 (France); Reischig, P. [Xnovo Technology ApS, 4600 Køge (Denmark); Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD (Netherlands); Adrien, J. [MATEIS, INSA de Lyon, Villeurbanne 69621 (France); Peetermans, S. [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Ludwig, W. [MATEIS, INSA de Lyon, Villeurbanne 69621 (France); European Synchrotron Radiation Facility, Grenoble 38043 (France)

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  17. Diffraction at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Khoze, V.A.; Ryskin, M.G. [University of Durham, Institute for Particle Physics Phenomenology, Durham (United Kingdom); NRC Kurchatov Institute, Gatchina, Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation); Martin, A.D. [University of Durham, Institute for Particle Physics Phenomenology, Durham (United Kingdom)

    2013-07-15

    We show that the diffractive pp (and p anti p) data (on {sigma}{sub tot}, d{sigma}{sub el}/dt, proton dissociation into low-mass systems, {sigma}{sup D}{sub low} {sub M}, and high-mass dissociation, d{sigma}/d({Delta}{eta})) in a wide energy range from CERN-ISR to LHC energies, may be described in a two-channel eikonal model with only one 'effective' pomeron. By allowing the pomeron coupling to the diffractive eigenstates to depend on the collider energy (as is expected theoretically) we are able to explain the low value of {sigma}{sup D}{sub low} {sub M} measured at the LHC. We calculate the survival probability, S{sup 2}, of a rapidity gap to survive 'soft rescattering'. We emphasise that the values found for S{sup 2} are particularly sensitive to the detailed structure of the diffractive eigenstates. (orig.)

  18. Nonlinear Reconstruction

    CERN Document Server

    Zhu, Hong-Ming; Pen, Ue-Li; Chen, Xuelei; Yu, Hao-Ran

    2016-01-01

    We present a direct approach to non-parametrically reconstruct the linear density field from an observed non-linear map. We solve for the unique displacement potential consistent with the non-linear density and positive definite coordinate transformation using a multigrid algorithm. We show that we recover the linear initial conditions up to $k\\sim 1\\ h/\\mathrm{Mpc}$ with minimal computational cost. This reconstruction approach generalizes the linear displacement theory to fully non-linear fields, potentially substantially expanding the BAO and RSD information content of dense large scale structure surveys, including for example SDSS main sample and 21cm intensity mapping.

  19. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  20. Diffractive Dijet Photoproduction

    CERN Document Server

    Klasen, M

    2005-01-01

    We have calculated diffractive dijet production in deep-inelastic scattering (DIS) at low-Q^2 and next-to-leading order (NLO) of perturbative QCD, including contributions from direct and resolved photons. We study how the cross section depends on the factorization scheme and scale M_\\gamma at the virtual photon vertex for the occurance of factorization breaking. The strong M_\\gamma-dependence, which is present when only the resolved cross section is suppressed, is tamed by intodrucing the suppression also in the initial-state NLO correction of the direct part.

  1. Nonlinear optimization

    CERN Document Server

    Ruszczynski, Andrzej

    2011-01-01

    Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates t

  2. Inclusive Hard Diffraction at HERA

    CERN Document Server

    Proskuryakov, Alexander

    2010-01-01

    Recent data from the H1 and ZEUS experiments on hard inclusive diffraction are discussed. Results of QCD analyses of the diffractive deep-inelastic scattering processes are reported. Predictions based on the extracted parton densities are compared to diffractive dijet measurements.

  3. Field Guide to Diffractive Optics

    CERN Document Server

    Soskind, Yakov

    2011-01-01

    This SPIE Field Guide provides the operational principles and established terminology of diffractive optics as well as a comprehensive overview of the main types of diffractive optics components. An emphasis is placed on the qualitative explanation of the diffraction phenomenon by the use of field distributions and graphs, providing the basis for understanding the fundamental relations and important trends.

  4. Analyses and computations of asymmetric Z-scan for large phase shift from diffraction theory

    Institute of Scientific and Technical Information of China (English)

    Liyong Ren(任立勇); Baoli Yao(姚保利); Xun Hou(侯洵); Liren Liu(刘立人); Changhe Zhou(周常河)

    2003-01-01

    Based on Fresnel-Kirchhoff diffraction theory, we set up a diffraction model of nonlinear optical media toGaussian beam, which can interpret the Z-scan phenomenon from a new way. This theory is not onlywell consistent with the conventional Z-scan theory in the case of small nonlinear phase shift, but alsocan fit for the lager nonlinear phase shift. Numeric computations indicate the shape of the Z-scan curveis greatly affected by the value of the nonlinear phase shift. The symmetric dispersion-like Z-scan curveis only valid for small nonlinear phase shift (|△φo| <π), but with increasing the nonlinear phase shift, thevalley of the transmittance is severely suppressed and the peak is greatly enhanced. Further calculationsshow some new interesting results.

  5. Quantum well nonlinear microcavities

    Science.gov (United States)

    Oudar, J. L.; Kuszelewicz, R.; Sfez, B.; Pellat, D.; Azoulay, R.

    We report on recent progress in reducing the power threshold of all-optical bistable quantum well vertical microcavities. Significant improvements are achieved through an increase of the cavity finesse, together with a reduction of the device active layer thickness. A critical intensity of 5 μW/μm 2 has been observed on a microcavity of finesse 250, with a nonlinear medium of only 18 GaAs quantum wells of 10 nm thickness. Further improvements of the Bragg mirror quality resulted in a finesse of 700 and a power-lifetime product of 15 fJ/μm 2. Microresonator pixellation allows to obtain 2-dimensional arrays. A thermally-induced alloy-mixing technique is described, which produced a 110 meV carrier confinement energy, together with a refractive index change of -.012, averaged over the 2.6 μm nonlinear medium thickness. The resulting electrical and optical confinement is shown to improve the nonlinear characteristics, by limiting lateral carrier diffusion and light diffraction.

  6. Generation of arbitrary complex quasi-non-diffracting optical patterns

    CERN Document Server

    Ortiz-Ambriz, Antonio; Kartashov, Yaroslav V; Vysloukh, Victor A; Petrov, Dmitri; Garcia-Gracia, Hipolito; Gutiérrez-Vega, Julio C; Torner, Lluis

    2013-01-01

    Due to their unique ability to maintain an intensity distribution upon propagation, non-diffracting light fields are used extensively in various areas of science, including optical tweezers, nonlinear optics and quantum optics, in applications where complex transverse field distributions are required. However, the number and type of rigorously non-diffracting beams is severely limited because their symmetry is dictated by one of the coordinate system where the Helmholtz equation governing beam propagation is separable. Here, we demonstrate a powerful technique that allows the generation of a rich variety of quasi-non-diffracting optical beams featuring nearly arbitrary intensity distributions in the transverse plane. These can be readily engineered via modifications of the angular spectrum of the beam in order to meet the requirements of particular applications. Such beams are not rigorously non-diffracting but they maintain their shape over large distances, which may be tuned by varying the width of the angu...

  7. Hard Diffraction in Pythia 8

    CERN Document Server

    Rasmussen, Christine O

    2015-01-01

    We present an overview of the options for diffraction implemented in the general--purpose event generator Pythia 8. We review the existing model for low-- and high--mass soft diffraction and present a new model for hard diffraction in pp and ppbar collisions. Both models uses the Pomeron approach pioneered by Ingelman and Schlein, factorising the single diffractive cross section into a Pomeron flux and a Pomeron PDF. The model for hard diffraction is implemented as a part of the multiparton interactions framework, thereby introducing a dynamical rapidity gap survival probability that explicitly breaks factorisation.

  8. Hard Diffraction in Pythia 8

    CERN Document Server

    Rasmussen, Christine O

    2015-01-01

    We present an overview of the options for diffraction implemented in the general-purpose event generator Pythia 8. We review the existing model for soft diffraction and present a new model for hard diffraction. Both models use the Pomeron approach pioneered by Ingelman and Schlein, factorising the diffractive cross section into a Pomeron flux and a Pomeron PDF, with several choices for both implemented in Pythia 8. The model of hard diffraction is implemented as a part of the multiparton interactions (MPI) framework, thus introducing a dynamical gap survival probability that explicitly breaks factorisation.

  9. Hard diffraction in Pythia 8

    Science.gov (United States)

    Overgaard Rasmussen, Christine

    2016-07-01

    We present an overview of the options for diffraction implemented in the general-purpose event generator Pythia 8 [1]. We review the existing model for soft diffraction and present a new model for hard diffraction. Both models use the Pomeron approach pioneered by Ingelman and Schlein, factorising the diffractive cross section into a Pomeron flux and a Pomeron PDF, with several choices for both implemented in Pythia 8. The model of hard diffraction is implemented as a part of the multiparton interactions (MPI) framework, thus introducing a dynamical gap survival probability that explicitly breaks factorisation.

  10. Nonlinear channelizer

    Science.gov (United States)

    In, Visarath; Longhini, Patrick; Kho, Andy; Neff, Joseph D.; Leung, Daniel; Liu, Norman; Meadows, Brian K.; Gordon, Frank; Bulsara, Adi R.; Palacios, Antonio

    2012-12-01

    The nonlinear channelizer is an integrated circuit made up of large parallel arrays of analog nonlinear oscillators, which, collectively, serve as a broad-spectrum analyzer with the ability to receive complex signals containing multiple frequencies and instantaneously lock-on or respond to a received signal in a few oscillation cycles. The concept is based on the generation of internal oscillations in coupled nonlinear systems that do not normally oscillate in the absence of coupling. In particular, the system consists of unidirectionally coupled bistable nonlinear elements, where the frequency and other dynamical characteristics of the emergent oscillations depend on the system's internal parameters and the received signal. These properties and characteristics are being employed to develop a system capable of locking onto any arbitrary input radio frequency signal. The system is efficient by eliminating the need for high-speed, high-accuracy analog-to-digital converters, and compact by making use of nonlinear coupled systems to act as a channelizer (frequency binning and channeling), a low noise amplifier, and a frequency down-converter in a single step which, in turn, will reduce the size, weight, power, and cost of the entire communication system. This paper covers the theory, numerical simulations, and some engineering details that validate the concept at the frequency band of 1-4 GHz.

  11. Birefringent coherent diffraction imaging

    Science.gov (United States)

    Karpov, Dmitry; dos Santos Rolo, Tomy; Rich, Hannah; Kryuchkov, Yuriy; Kiefer, Boris; Fohtung, E.

    2016-10-01

    Directional dependence of the index of refraction contains a wealth of information about anisotropic optical properties in semiconducting and insulating materials. Here we present a novel high-resolution lens-less technique that uses birefringence as a contrast mechanism to map the index of refraction and dielectric permittivity in optically anisotropic materials. We applied this approach successfully to a liquid crystal polymer film using polarized light from helium neon laser. This approach is scalable to imaging with diffraction-limited resolution, a prospect rapidly becoming a reality in view of emergent brilliant X-ray sources. Applications of this novel imaging technique are in disruptive technologies, including novel electronic devices, in which both charge and spin carry information as in multiferroic materials and photonic materials such as light modulators and optical storage.

  12. Radial Reflection Diffraction Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K; Norton, S J

    2003-10-10

    We develop a wave-based tomographic imaging algorithm based upon a single rotating radially outward oriented transducer. At successive angular locations at a fixed radius, the transducer launches a primary field and collects the backscattered field in a ''pitch/catch'' operation. The hardware configuration, operating mode, and data collection method is identical to that of most medical intravascular ultrasound (IVUS) systems. IVUS systems form images of the medium surrounding the probe based upon ultrasonic B-scans, using a straight-ray model of sound propagation. Our goal is to develop a wave-based imaging algorithm using diffraction tomography techniques. Given the hardware configuration and the imaging method, we refer to this system as ''radial reflection diffraction tomography.'' We consider two hardware configurations: a multimonostatic mode using a single transducer as described above, and a multistatic mode consisting of a single transmitter and an aperture formed by multiple receivers. In this latter case, the entire source/receiver aperture rotates about the fixed radius. Practically, such a probe is mounted at the end of a catheter or snaking tube that can be inserted into a part or medium with the goal of forming images of the plane perpendicular to the axis of rotation. We derive an analytic expression for the multimonostatic inverse but ultimately use the new Hilbert space inverse wave (HSIW) algorithm to construct images using both operating modes. Applications include improved IVUS imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts with existing access holes.

  13. Nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Turchetti, G. (Bologna Univ. (Italy). Dipt. di Fisica)

    1989-01-01

    Research in nonlinear dynamics is rapidly expanding and its range of applications is extending beyond the traditional areas of science where it was first developed. Indeed while linear analysis and modelling, which has been very successful in mathematical physics and engineering, has become a mature science, many elementary phenomena of intrinsic nonlinear nature were recently experimentally detected and investigated, suggesting new theoretical work. Complex systems, as turbulent fluids, were known to be governed by intrinsically nonlinear laws since a long time ago, but received purely phenomenological descriptions. The pioneering works of Boltzmann and Poincare, probably because of their intrinsic difficulty, did not have a revolutionary impact at their time; it is only very recently that their message is reaching a significant number of mathematicians and physicists. Certainly the development of computers and computer graphics played an important role in developing geometric intuition of complex phenomena through simple numerical experiments, while a new mathematical framework to understand them was being developed.

  14. Nonlinear Systems.

    Science.gov (United States)

    Seider, Warren D.; Ungar, Lyle H.

    1987-01-01

    Describes a course in nonlinear mathematics courses offered at the University of Pennsylvania which provides an opportunity for students to examine the complex solution spaces that chemical engineers encounter. Topics include modeling many chemical processes, especially those involving reaction and diffusion, auto catalytic reactions, phase…

  15. Study of optical Laue diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarthy, Giridhar, E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com; Allam, Srinivasa Rao, E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com; Satyanarayana, S. V. M., E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com; Sharan, Alok, E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com [Department of Physics, Pondicherry University, Puducherry-605014 (India)

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  16. Diffractive optics and nanophotonics resolution below the diffraction limit

    CERN Document Server

    Minin, Igor

    2016-01-01

    In this book the authors present several examples of techniques used to overcome the Abby diffraction limit using flat and 3D diffractive optical elements, photonic crystal lenses, photonic jets, and surface plasmon diffractive optics. The structures discussed can be used in the microwave and THz range and also as scaled models for optical frequencies. Such nano-optical microlenses can be integrated, for example, into existing semiconductor heterostructure platforms for next-generation optoelectronic applications. Chapter 1 considers flat diffractive lenses and innovative 3D radiating structures including a conical millimeter-wave Fresnel zone plate (FZP) lens proposed for subwavelength focusing. In chapter 2 the subwavelength focusing properties of diffractive photonic crystal lenses are considered and it is shown that at least three different types of photonic crystal lens are possible.  With the aim of achieving subwavelength focusing, in chapter 3 an alternative mechanism to produce photonic jets at Tera...

  17. Dispersion managed solitons in the presence of saturated nonlinearity

    Science.gov (United States)

    Hundertmark, Dirk; Lee, Young-Ran; Ried, Tobias; Zharnitsky, Vadim

    2017-10-01

    The averaged dispersion managed nonlinear Schrödinger equation with saturated nonlinearity is considered. It is shown that under rather general assumptions on the saturated nonlinearity, the ground state solution corresponding to the dispersion managed soliton can be found for both zero residual dispersion and positive residual dispersion. The same applies to diffraction management solitons, which are a discrete version describing certain waveguide arrays.

  18. Nonlinear PDEs

    OpenAIRE

    2015-01-01

    From the Back Cover: The emphasis throughout the present volume is on the practical application of theoretical mathematical models helping to unravel the underlying mechanisms involved in processes from mathematical physics and biosciences. It has been conceived as a unique collection of abstract methods dealing especially with nonlinear partial differential equations (either stationary or evolutionary) that are applied to understand concrete processes involving some important applications re...

  19. Diffractive Bremsstrahlung in Hadronic Collisions

    Directory of Open Access Journals (Sweden)

    Roman Pasechnik

    2015-01-01

    Full Text Available Production of heavy photons (Drell-Yan, gauge bosons, Higgs bosons, and heavy flavors, which is treated within the QCD parton model as a result of hard parton-parton collision, can be considered a bremsstrahlung process in the target rest frame. In this review, we discuss the basic features of the diffractive channels of these processes in the framework of color dipole approach. The main observation is a dramatic breakdown of diffractive QCD factorisation due to the interplay between soft and hard interactions, which dominates these processes. This observation is crucial for phenomenological studies of diffractive reactions in high energy hadronic collisions.

  20. Grazing incidence diffraction : A review

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, B. [LTPCM, ENSEEG. St. Martin d`Heres. (France)

    1996-09-01

    Different Grazing Incidence Diffraction (GID) methods for the analysis of thin films and multilayer structures are reviewed in three sections: the reflectivity is developed in the first one, which includes the non-specular diffuse scattering. The second one is devoted to the extremely asymmetric Bragg diffraction and the third one to the in-plane Bragg diffraction. Analytical formulations of the scattered intensities are developed for each geometry, in the framework of the kinetical analysis as well as the dynamical theory. Experimental examples are given to illustrate the quantitative possibility of the GID techniques.

  1. The diffractive achromat full spectrum computational imaging with diffractive optics

    KAUST Repository

    Peng, Yifan

    2016-07-11

    Diffractive optical elements (DOEs) have recently drawn great attention in computational imaging because they can drastically reduce the size and weight of imaging devices compared to their refractive counterparts. However, the inherent strong dispersion is a tremendous obstacle that limits the use of DOEs in full spectrum imaging, causing unacceptable loss of color fidelity in the images. In particular, metamerism introduces a data dependency in the image blur, which has been neglected in computational imaging methods so far. We introduce both a diffractive achromat based on computational optimization, as well as a corresponding algorithm for correction of residual aberrations. Using this approach, we demonstrate high fidelity color diffractive-only imaging over the full visible spectrum. In the optical design, the height profile of a diffractive lens is optimized to balance the focusing contributions of different wavelengths for a specific focal length. The spectral point spread functions (PSFs) become nearly identical to each other, creating approximately spectrally invariant blur kernels. This property guarantees good color preservation in the captured image and facilitates the correction of residual aberrations in our fast two-step deconvolution without additional color priors. We demonstrate our design of diffractive achromat on a 0.5mm ultrathin substrate by photolithography techniques. Experimental results show that our achromatic diffractive lens produces high color fidelity and better image quality in the full visible spectrum. © 2016 ACM.

  2. Measurement of low-frequency ultrasonic wave in water using an acoustic fiber sensor.

    Science.gov (United States)

    Sakoda, Tatsuya; Sonoda, Yoshito

    2006-04-01

    An acoustic fiber sensor for measurement of ultrasonic waves, which used the approximate Raman-Nath diffraction effect where light diffraction waves were generated in an optical fiber by strain due to the ultrasonic waves, was proposed and examined. In order to characterize the acoustic fiber sensor as a basic study, measurements of low-frequency ultrasonic waves in water were examined using a step index fiber operating as a detection sensor. The results showed that characteristics of detected signals agreed with the theoretical prediction based on Fraunhofer diffraction. This indicates that our proposed fiber sensor can be used for the detection of low-frequency ultrasonic waves as well as the transmission of light diffraction signals.

  3. Multiple annular linear diffractive axicons.

    Science.gov (United States)

    Bialic, Emilie; de la Tocnaye, Jean-Louis de Bougrenet

    2011-04-01

    We propose a chromatic analysis of multiple annular linear diffractive axicons. Large aperture axicons are optical devices providing achromatic nondiffracting beams, with an extended depth of focus, when illuminated by a white light source, due to chromatic foci superimposition. Annular apertures introduce chromatic foci separation, and because chromatic aberrations result in focal segment axial shifts, polychromatic imaging properties are partially lost. We investigate here various design parameters that can be used to achieve color splitting, filtering, and combining using these properties. In order to improve the low-power efficiency of a single annular axicon, we suggest a spatial multiplexing of concentric annular axicons with different sizes and periods we call multiple annular aperture diffractive axicons (MALDAs). These are chosen to maintain focal depths while enabling color imaging with sufficient diffraction efficiency. Illustrations are given for binary phase diffractive axicons, considering technical aspects such as grating design wavelength and phase dependence due to the grating thickness.

  4. Unified approach to hard diffraction

    CERN Document Server

    Peschanski, R

    2001-01-01

    Using a combination of S-Matrix and perturbative QCD properties in the small x_{Bj} regime, we propose a formulation of hard diffraction unifying the partonic (Ingelman-Schlein) Pomeron, Soft Colour Interaction and QCD dipole descriptions.

  5. X-Ray Diffraction Apparatus

    Science.gov (United States)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  6. New CDF results on diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Mesropian, Christina; /Rockefeller U.

    2006-12-01

    We report new diffraction results obtained by the CDF collaboration in proton-antiproton collisions at the Fermilab Tevatron collider at {radical}s=1.96 TeV. The first experimental evidence of exclusive dijet and diphoton production is presented. The exclusive results are discussed in context of the exclusive Higgs production at LHC. We also present the measurement of the Q{sup 2} and t dependence of the diffractive structure function.

  7. Measurement and fitting techniques for the assessment of material nonlinearity using nonlinear Rayleigh waves

    Energy Technology Data Exchange (ETDEWEB)

    Torello, David [GW Woodruff School of Mechanical Engineering, Georgia Tech (United States); Kim, Jin-Yeon [School of Civil and Environmental Engineering, Georgia Tech (United States); Qu, Jianmin [Department of Civil and Environmental Engineering, Northwestern University (United States); Jacobs, Laurence J. [School of Civil and Environmental Engineering, Georgia Tech and GW Woodruff School of Mechanical Engineering, Georgia Tech (United States)

    2015-03-31

    This research considers the effects of diffraction, attenuation, and the nonlinearity of generating sources on measurements of nonlinear ultrasonic Rayleigh wave propagation. A new theoretical framework for correcting measurements made with air-coupled and contact piezoelectric receivers for the aforementioned effects is provided based on analytical models and experimental considerations. A method for extracting the nonlinearity parameter β{sub 11} is proposed based on a nonlinear least squares curve-fitting algorithm that is tailored for Rayleigh wave measurements. Quantitative experiments are conducted to confirm the predictions for the nonlinearity of the piezoelectric source and to demonstrate the effectiveness of the curve-fitting procedure. These experiments are conducted on aluminum 2024 and 7075 specimens and a β{sub 11}{sup 7075}/β{sub 11}{sup 2024} measure of 1.363 agrees well with previous literature and earlier work.

  8. A nonlinear RDF model for waves propagating in shallow water

    Institute of Scientific and Technical Information of China (English)

    王厚杰; 杨作升; 李瑞杰; 张军

    2001-01-01

    In this paper, a composite explicit nonlinear dispersion relation is presented with reference to Stokes 2nd order dispersion relation and the empirical relation of Hedges. The explicit dispersion relation has such advantages that it can smoothly match the Stokes relation in deep and intermediate water and Hedgs’s relation in shallow water. As an explicit formula, it separates the nonlinear term from the linear dispersion relation. Therefore it is convenient to obtain the numerical solution of nonlinear dispersion relation. The present formula is combined with the modified mild-slope equation including nonlinear effect to make a Refraction-Diffraction (RDF) model for wave propagating in shallow water. This nonlinear model is verified over a complicated topography with two submerged elliptical shoals resting on a slope beach. The computation results compared with those obtained from linear model show that at present the nonlinear RDF model can predict the nonlinear characteristics and the combined refracti

  9. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  10. Nonlinear Dynamics

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    3.1 A Unified Nonlinear Feedback Functional Method for Study Both Control and Synchronization of Spatiotemporal Chaos Fang Jinqing Ali M. K. (Department of Physics, The University of Lethbridge,Lethbridge, Alberta T1K 3M4,Canada) Two fundamental questions dominate future chaos control theories.The first is the problem of controlling hyperchaos in higher dimensional systems.The second question has yet to be addressed:the problem of controlling spatiotemporal chaos in a spatiotemporal system.In recent years, control and synchronization of spatiotemporal chaos and hyperchaos have became a much more important and challenging subject. The reason for this is the control and synchronism of such behaviours have extensive and great potential of interdisciplinary applications, such as security communication, information processing, medicine and so on. However, this subject is not much known and remains an outstanding open.

  11. Enhancing electron diffraction through precession

    Energy Technology Data Exchange (ETDEWEB)

    Pavia, Giuseppe; Benner, Gerd; Niebel, Harald [Carl Zeiss NTS, Oberkochen (Germany); Patout, Loic [ONERA, Paris (France)

    2011-07-01

    Nanostructures are often investigated in Transmission Electron Microscopy (TEM), and electron diffraction (ED) can be used to solve nanocrystals. Electrons interact very strongly with matter, and the diffracted intensities are highly dynamical. Precession Electron Diffraction (PED) is a recent technique delivering more kinematical diffraction patterns. We have used an in column energy filtered TEM equipped with precession electron diffraction hardware, which allows working up to 3 precession angle, and energy filtering of the precession patterns. High Order Laue Zones, useful for space group symmetry determination and to enhance fine structure details, appear more clearly. We have compared a microdiffraction pattern and a precession microdiffraction pattern performed along the orientation [010] of a sample TiSi{sub 2} with a space group Fddd. For cubic systems, this orientation allows to distinguish the Bravais lattice and the presence of glide mirrors. We show that with precession, we conserve the distinction of the gap and the difference of periodicity between the ZOLZ and the FOLZ is improved.

  12. Diffraction past, present and future

    CERN Document Server

    Predazzi, Enrico

    1998-01-01

    Hadronic diffraction has become a hot and fashionable subject in recent years due to the great interest triggered by the HERA and Tevatron data. These data have helped to put the field in a different perspective paving the road to a hopefully more complete understanding than hitherto achieved. The forthcoming data in the next few years from even higher energies (LHC) promise to sustain this interest for a long time. It is, therefore, necessary to provide the younger generations with as complete as possible discussion of the main developments that have marked the growth of high energy diffractive physics in the past and to assess the present state of the art. For this reason, this part will be by far the largest. The analysis of the relationship between conventional diffractive physics and the low-x physics from deep inelastic scattering will allow us also to review the instruments which could help to understand the developments we can expect from the future.

  13. Diffractive dijet production at HERA

    CERN Document Server

    Bruni, A; Krämer, G; Schatzel, S

    2005-01-01

    We present recent experimental data from the H1 and ZEUS Collaborations at HERA for diffractive dijet production in deep-inelastic scattering (DIS) and photoproduction and compare them with next-to-leading order (NLO) QCD predictions using diffractive parton densities. While good agreement is found for DIS, the dijet photoproduction data are overestimated by the NLO theory, showing that factorization breaking occurs at this order. While this is expected theoretically for resolved photoproduction, the fact that the data are better described by a global suppression of direct and resolved contribution by about a factor of two comes as a surprise. We therefore discuss in some detail the factorization scheme and scale dependence between direct and resolved contributions and propose a new factorization scheme for diffractive dijet photoproduction.

  14. Nonlinear Materials Characterization Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Nonlinear Materials Characterization Facility conducts photophysical research and development of nonlinear materials operating in the visible spectrum to protect...

  15. Derivation of an Applied Nonlinear Schroedinger Equation.

    Energy Technology Data Exchange (ETDEWEB)

    Pitts, Todd Alan; Laine, Mark Richard; Schwarz, Jens; Rambo, Patrick K.; Karelitz, David B.

    2015-01-01

    We derive from first principles a mathematical physics model useful for understanding nonlinear optical propagation (including filamentation). All assumptions necessary for the development are clearly explained. We include the Kerr effect, Raman scattering, and ionization (as well as linear and nonlinear shock, diffraction and dispersion). We explain the phenomenological sub-models and each assumption required to arrive at a complete and consistent theoretical description. The development includes the relationship between shock and ionization and demonstrates why inclusion of Drude model impedance effects alters the nature of the shock operator. Unclassified Unlimited Release

  16. Derivation of an applied nonlinear Schroedinger equation

    Energy Technology Data Exchange (ETDEWEB)

    Pitts, Todd Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Laine, Mark Richard [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Schwarz, Jens [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Rambo, Patrick K. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    We derive from first principles a mathematical physics model useful for understanding nonlinear optical propagation (including filamentation). All assumptions necessary for the development are clearly explained. We include the Kerr effect, Raman scattering, and ionization (as well as linear and nonlinear shock, diffraction and dispersion). We explain the phenomenological sub-models and each assumption required to arrive at a complete and consistent theoretical description. The development includes the relationship between shock and ionization and demonstrates why inclusion of Drude model impedance effects alters the nature of the shock operator. Unclassified Unlimited Release

  17. Acoustooptic Diffraction in Borate Crystals

    CERN Document Server

    Martynyuk-Lototska, I; Krupych, O; Adamiv, V; Smirnov, Ye; Vlokh, R

    2004-01-01

    The efficiency of acoustooptic (AO) diffraction in a-BaB2O4 and Li2B4O7 crystals is studied experimentally. The crystals are shown to be quite good AO materials. The efficiency of AO diffraction in a-BaB2O4 reaches h=30% at the electric signal power of P=0.7W for the transverse acoustic wave and 15% at the power of P=0.56W for the longitudinal wave. The same parameter for Li2B4O7 reaches h=21% at P=0,81W for the longitudinal acoustic wave.

  18. High-pressure neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongwu [Los Alamos National Laboratory

    2011-01-10

    This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

  19. Femtosecond index grating in barium flouride: efficient self-diffraction and enhancement of surface SHG

    Science.gov (United States)

    Schneider, Th; Wolfframm, D.; Mitzner, R.; Reif, J.

    2000-02-01

    A transient refractive index grating is formed in barium fluoride crystals under irradiation with femtosecond laser pulses from two non-collinear beams. At low intensities energy coupling takes place. At high intensities, a typical self-diffraction pattern is obtained with a diffraction efficiency better than 10%. Simultaneously, an enhancement of the SHG signal from the surface, as well as the generation and diffraction of the third harmonic is observable. For all effects the nonlinear Kerr-effect is responsible, with the response time being limited only by the temporal pulse shape.

  20. Nonlinear singular vectors and nonlinear singular values

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A novel concept of nonlinear singular vector and nonlinear singular value is introduced, which is a natural generalization of the classical linear singular vector and linear singular value to the nonlinear category. The optimization problem related to the determination of nonlinear singular vectors and singular values is formulated. The general idea of this approach is demonstrated by a simple two-dimensional quasigeostrophic model in the atmospheric and oceanic sciences. The advantage and its applications of the new method to the predictability, ensemble forecast and finite-time nonlinear instability are discussed. This paper makes a necessary preparation for further theoretical and numerical investigations.

  1. Hard diffraction and rapidity gaps

    Energy Technology Data Exchange (ETDEWEB)

    Albrow, M.G.

    1994-08-01

    I describe the evolution of experiments at hadron colliders on (a) high mass diffraction (b) double pomeron exchange, from the ISR through the Sp{bar p}S to the Tevatron. I emphasize an experimental approach to the question: ``What is the pomeron?``

  2. Diffractive charged meson pair production

    CERN Document Server

    Lehmann-Dronke, B; Schäfer, S; Stein, E; Schäfer, A

    1999-01-01

    We investigate the possibility to measure the nonforward gluon distribution function by means of diffractively produced charged pion and kaon pairs in polarized lepton nucleon scattering. The resulting cross sections are sizable and are dominated by the gluonic contribution. We find large spin asymmetries, both for pion pairs and for kaon pairs.

  3. 3D -Ray Diffraction Microscopy

    DEFF Research Database (Denmark)

    Poulsen, Henning Friis; Schmidt, Søren; Juul Jensen, Dorte

    2014-01-01

    Three-dimensional X-ray diffraction (3DXRD) microscopy is a fast and non-destructive structural characterization technique aimed at the study of individual crystalline elements (grains or subgrains) within mm-sized polycrystalline specimens. It is based on two principles: the use of highly penetr...

  4. Stretchable diffraction gratings for spectrometry

    NARCIS (Netherlands)

    Simonov, A.N.; Grabarnik, S.; Vdovine, G.V

    2007-01-01

    We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly cha

  5. Unifying approach to hard diffraction

    CERN Document Server

    Navelet, H

    2001-01-01

    We find a formulation of hard diffraction unifying the partonic (Ingelman-Schlein) Pomeron, Soft Colour Interaction and QCD dipole descriptions. A theoretical interpretation in terms of S-Matrix and perturbative QCD properties in the small x_{Bj} regime is proposed.

  6. Progress in Diffraction Enhanced Imaging

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ In cooperation with the Topography Station of Beijing Synchrotron Radiation under CAS Institute of High Energy Physics, a research group from the CAS Shanghai Institute of Optics and Fine Mechanics (SIOM) has made encouraging progress in the diffraction enhanced imaging technology through phase-contrast microscope by hard X-rays.

  7. A QCD analysis of ZEUS diffractive data

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2009-11-15

    ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (orig.)

  8. Low-Mass Diffraction at the LHC

    CERN Document Server

    Jenkovszky, Laszlo; Lämsä, Jerry; Orava, Risto

    2011-01-01

    The expected resonance structure for the low-mass single diffractive states from a Regge-dual model elaborated paper by the present authors in a previous is predicted. Estimates for the observable low-mass single diffraction dissociation (SDD) cross sections and efficiencies for single diffractive events simulated by PYTHIA 6.2 as a function of the diffractive mass are given.

  9. Diffractive and Exclusive Processes at CMS

    CERN Document Server

    Kuznetsova, Ekaterina

    2014-01-01

    We present an overview of the CMS results on diffractive and exclusive production.Measurements of inclusive single and double diffractive production are discussedas well as measurements of the diffractive production at a hard scale. Measurementsof charged particle multiplicities for single diffractive enhanced data sample and studies of central diffractive jet production were perfrmed in a collaboration with the TOTEM experiment. CMS results on cross section measurements for exclusive dilepton and WW production are also presented.

  10. Diffractive Interaction for Short Pulses in 2×2 System

    Institute of Scientific and Technical Information of China (English)

    YUAN Ming-sheng

    2008-01-01

    This paper studies the asymptotic behavior of the diffractive interaction of pulses with two linear phases of length ε << 1 in 2 × 2 semilinear strictly hyperbolic system with constant coefficients. By a formal analysis, it derives problems of profiles in the expansion of the pulse like solution with respect to the length ε, and obtains that the leading profile satisfies a nonlinear Schrodinger type system. The problems of profiles are solved, and the formal expansion is justified. It is observed that there is interaction between two phases starting at the third order profiles.

  11. Nonlinear Spectral-Spatial Control and Localization of Supercontinuum Radiation

    Science.gov (United States)

    Neshev, Dragomir N.; Sukhorukov, Andrey A.; Dreischuh, Alexander; Fischer, Robert; Ha, Sangwoo; Bolger, Jeremy; Bui, Lam; Krolikowski, Wieslaw; Eggleton, Benjamin J.; Mitchell, Arnan; Austin, Michael W.; Kivshar, Yuri S.

    2007-09-01

    We present the first observation of spatiospectral control and localization of supercontinuum light through the nonlinear interaction of spectral components in extended periodic structures. We use an array of optical waveguides in a LiNbO3 crystal and employ the interplay between diffraction and nonlinearity to dynamically control the output spectrum of the supercontinuum radiation. This effect presents an efficient scheme for optically tunable spectral filtering of supercontinua.

  12. Application of Novel Nonlinear Optical Materials to Optical Processing

    Science.gov (United States)

    Banerjee, Partha P.

    1999-01-01

    We describe wave mixing and interactions in nonlinear photorefractive polymers and disodium flourescein. Higher diffracted orders yielding forward phase conjugation can be generated in a two-wave mixing geometry in photorefractive polymers, and this higher order can be used for image edge enhancement and correlation. Four-wave mixing and phase conjugation is studied using nonlinear disodium floureschein, and the nature and properties of gratings written in this material are investigated.

  13. Phase Aberrations in Diffraction Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M

    2005-09-29

    In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.

  14. Diffraction operators in paraxial approach

    Science.gov (United States)

    Lasso, William; Navas, Marianela; Añez, Liz; Urdaneta, Romer; Díaz, Leonardo; Torres, César O.

    2014-07-01

    Nowadays, research in the field of science education points to the creation of alternative ways of teaching contents encouraging the development of more elaborate reasoning, where a high degree of abstraction and generalization of scientific knowledge prevails. On that subject, this research shows a didactic alternative proposal for the construction of Fresnel and Fraunhoffer diffraction concepts applying the Fourier transform technique in the study of electromagnetic waves propagation in free space. Curvature transparency and Fourier sphere operators in paraxial approximation are used in order to make the usual laborious mathematical approach easier. The main result shows that the composition of optic metaxial operators results in the discovery of a simpler way out of the standard electromagnetic wave propagation in free space between a transmitter and a receptor separated from a given distance. This allows to state that the didactic proposal shown encourages the construction of Fresnel and Fraunhoffer diffraction concepts in a more effective and easier way than the traditional teaching.

  15. Polarimetry by classical ghost diffraction

    CERN Document Server

    Kellock, Henri; Friberg, Ari T; Shirai, Tomohiro

    2014-01-01

    We present a technique for studying the polarimetric properties of a birefringent object by means of classical ghost diffraction. The standard ghost diffraction setup is modified to include polarizers for controlling the state of polarization of the beam in various places. The object is characterized by a Jones matrix and the absolute values of the Fourier transforms of its individual elements are measured. From these measurements the original complex-valued functions can be retrieved through iterative methods resulting in the full Jones matrix of the object. We present two different placements of the polarizers and show that one of them leads to better polarimetric quality, while the other placement offers the possibility to perform polarimetry without controlling the source's state of polarization. The concept of an effective source is introduced to simplify the calculations. Ghost polarimetry enables the assessment of polarization properties as a function of position within the object through simple intens...

  16. NONLINEAR EXPECTATIONS AND NONLINEAR MARKOV CHAINS

    Institute of Scientific and Technical Information of China (English)

    PENG SHIGE

    2005-01-01

    This paper deals with nonlinear expectations. The author obtains a nonlinear generalization of the well-known Kolmogorov's consistent theorem and then use it to construct filtration-consistent nonlinear expectations via nonlinear Markov chains. Compared to the author's previous results, i.e., the theory of g-expectations introduced via BSDE on a probability space, the present framework is not based on a given probability measure. Many fully nonlinear and singular situations are covered. The induced topology is a natural generalization of Lp-norms and L∞-norm in linear situations.The author also obtains the existence and uniqueness result of BSDE under this new framework and develops a nonlinear type of von Neumann-Morgenstern representation theorem to utilities and present dynamic risk measures.

  17. Confinement, Turbulence and Diffraction Catastrophes

    Science.gov (United States)

    Blaizot, J.-P.; Nowak, M. A.

    2009-08-01

    Many features of the large N transition that occurs in the spectral density of Wilson loops as a function of loop area (observed recently in numerical simulations of Yang-Mills theory by Narayanan and Neuberger) can be captured by a simple Burgers equation used to model turbulence. Spectral shock waves that precede this asymptotic limit exhibit universal scaling with N, with indices that can be related to Berry indices for diffraction catastrophes.

  18. Comparative study of different Schlieren diffracting elements

    Indian Academy of Sciences (India)

    Raj Kumar; Sushil K Kaura; D P Chhachhia; D Mohan; A K Aggarwal

    2008-01-01

    This paper presents an analysis of diffraction effects taking place at different Schlieren diffracting elements. Two types of diffraction effects are prominent in the Schlieren schemes. One is diffraction of direct light (source image) at the Schlieren element, which limits the sensitivity and resolution of Schlieren systems. The second type is the diffraction of light deflected from the test object at the Schlieren-diffracting element. This second type of diffraction degrades the quality of Schlieren results. Experimental results showing the effect of diffraction of light deflected from the test object at a phase knife-edge, corner of a square phase aperture and an optical fiber tip as Schlieren diffracting elements have been presented and discussed.

  19. Stretchable diffraction gratings for spectrometry.

    Science.gov (United States)

    Simonov, Aleksey N; Grabarnik, Semen; Vdovin, Gleb

    2007-07-23

    We have investigated the possibility of using transparent stretchable diffraction gratings for spectrometric applications. The gratings were fabricated by replication of a triangular-groove master into a transparent viscoelastic. The sample length, and hence the spatial period, can be reversibly changed by mechanical stretching. When used in a monochromator with two slits, the stretchable grating permits scanning the spectral components over the output slit, converting the monochromator into a scanning spectrometer. The spectral resolution of such a spectrometer was found to be limited mainly by the wave-front aberrations due to the grating deformation. A model relating the deformation-induced aberrations in different diffraction orders is presented. In the experiments, a 12-mm long viscoelastic grating with a spatial frequency of 600 line pairs/mm provided a full-width at half-maximum resolution of up to ~1.2 nm in the 580-680 nm spectral range when slowly stretched by a micrometer screw and ~3 nm when repeatedly stretched by a voice coil at 15 Hz. Comparison of aberrations in transmitted and diffracted beams measured by a Shack- Hartmann wave-front sensor showed that astigmatisms caused by stretch-dependent wedge deformation are the main factors limiting the resolution of the viscoelastic-grating-based spectrometer.

  20. Weakly nonlinear analysis and localised structures in nonlinear cavities with metamaterials

    Science.gov (United States)

    Slimani, N.; Makhoute, A.; Tlidi, M.

    2016-04-01

    We consider an optical ring cavity filled with a metamaterial and with a Kerr medium. The cavity is driven by a coherent radiation beam. The modelling of this device leads to the well known Lugiato-Lefever equation with high order diffraction term. We assume that both left-handed and right-handed materials possess a Kerr focusing type of nonlinearity. We show that close to the zero-diffraction regime, high-order diffraction effect allows us to stabilise dark localised structures in this device. These structures consist of dips or holes in the transverse profile of the intracavity field and do not exist without high-order diffraction effects. We show that high order diffraction effects alter in depth the space-time dynamics of this device. A weakly nonlinear analysis in the vicinity of the first threshold associated with the Turing instability is performed. This analysis allows us to determine the parameter regime where the transition from super- to sub-critical bifurcation occurs. When the modulational instability appears subcritically, we show that bright localised structures of light may be generated in two-dimensional setting. Close to the second threshold associated with the Turing instability, dark localised structures are generated.

  1. Analysis and Correction of Diffraction Effect on the B/A Measurement at High Frequencies

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dong(章东); GONG Xiu-Fen(龚秀芬); LIU Xiao-Zhou(刘晓宙); KUSHIBIKI Jun-ichi; NISHINO Hideo

    2004-01-01

    A numerical method is developed to analyse and to correct the diffraction effect in the measurement of acoustic nonlinearity parameter B/A at high frequencies. By using the KZK nonlinear equation and the superposition approach of Gaussian beams, an analytical model is derived to describe the second harmonic generation through multi-layer medium SiO2/liquid specimen/SiO2. Frequency dependence of the nonlinear characterization curve for water in 110-155 MHz is numerically and experimentally investigated. With the measured dip position and the new model, values of B/A for water are evaluated. The results show that the present method can effectively correct the diffraction effect in the measurement.

  2. Triple Bragg diffraction in paratellurite crystal

    Science.gov (United States)

    Kotov, V. M.; Averin, S. V.; Voronko, A. I.; Kotov, E. V.; Tikhomirov, S. A.

    2017-07-01

    Triple Bragg diffraction in a paratellurite crystal has been considered for the case when the plane of diffraction is oblique to the optical axis of the crystal. It has been shown that effective photoelastic constants for isotropic and anisotropic diffraction depend on the inclination of the plane of diffraction insignificantly. Triple Bragg diffraction of 0.63-μm coherent radiation in paratellurite at a 47.3-MHz slow acoustic wave has been experimentally demonstrated. For an optical power of 0.69 W delivered to a piezoconverter, the relative intensities of diffraction orders equal 0.4, 0.4, 0.1, and 0.1, respectively.

  3. From Ewald sphere to Ewald shell in nonlinear optics

    Science.gov (United States)

    Huang, Huang; Huang, Cheng-Ping; Zhang, Chao; Hong, Xu-Hao; Zhang, Xue-Jin; Qin, Yi-Qiang; Zhu, Yong-Yuan

    2016-07-01

    Ewald sphere is a simple vector scheme to depict the X-ray Bragg diffraction in a crystal. A similar method, known as the nonlinear Ewald sphere, was employed to illustrate optical frequency conversion processes. We extend the nonlinear Ewald sphere to the Ewald shell construction. With the Ewald shell, a variety of quasi-phase-matching (QPM) effects, such as the collective envelope effect associated with multiple QPM resonances, the enhanced second- harmonic generation due to multiple reciprocal vectors etc., are suggested theoretically and verified experimentally. By rotating the nonlinear photonic crystal sample, the dynamic evolution of these QPM effects has also been observed, which agreed well with the Ewald shell model.

  4. Diffraction structural biology – a new horizon

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Takashi [Nagoya Industrial Science Research Institute, 1-13 Yotsuya-dori, Chikusa-ku, Nagoya 464-0819 (Japan); Helliwell, John R. [University of Manchester, Manchester M13 9PL (United Kingdom); Johnson, John E. [Scripps Research Institute, San Diego, CA (United States); Yasuoka, Noritake, E-mail: nori-yasuoka@nifty.com [AIST Kansai Center, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Sakabe, Noriyoshi [Photon Factory, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2013-11-01

    An introductory overview to the special issue papers on diffraction structural biology in this issue of the journal. An introductory overview to the special issue papers on diffraction structural biology in this issue of the journal.

  5. 50 years of fiber diffraction.

    Science.gov (United States)

    Holmes, Kenneth C

    2010-05-01

    In 1955 Ken Holmes started working on tobacco mosaic virus (TMV) as a research student with Rosalind Franklin at Birkbeck College, London. Afterward he spent 18months as a post doc with Don Caspar and Carolyn Cohen at the Children's Hospital, Boston where he continued the work on TMV and also showed that the core of the thick filament of byssus retractor muscle from mussels is made of two-stranded alpha-helical coiled-coils. Returning to England he joined Aaron Klug's group at the newly founded Laboratory of Molecular Biology in Cambridge. Besides continuing the TMV studies, which were aimed at calculating the three-dimensional density map of the virus, he collaborated with Pringle's group in Oxford to show that two conformation of the myosin cross-bridge could be identified in insect flight muscle. In 1968 he opened the biophysics department at the Max Planck Institute for Medical Research in Heidelberg, Germany. With Gerd Rosenbaum he initiated the use of synchrotron radiation as a source for X-ray diffraction. In his lab the TMV structure was pushed to 4A resolution and showed how the RNA binds to the protein. With his co-workers he solved the structure of g-actin as a crystalline complex and then solved the structure of the f-actin filament by orientating the g-actin structure so as to give the f-actin fiber diffraction pattern. He was also able to solve the structure of the complex of actin with tropomyosin from fiber diffraction.

  6. Diffractive Production of the Higgs Boson

    CERN Document Server

    Peschanski, R

    2003-01-01

    Diffractive production of the Higgs boson at hadron colliders is discussed in the light of the observed rate of hard diffractive dijet events at the Tevatron. The Higgs predictions of models successful for dijets are compared. LHC seems promising for a diffractive light Higgs boson and its mass determination. Hard diffractive dijets, diphotons and dileptons at the Tevatron (Run II) will be necessary to remove the remaining large uncertainties on cross-sections and signals.

  7. Undergraduate Experiment with Fractal Diffraction Gratings

    Science.gov (United States)

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  8. Diffractive molecular-orbital tomography

    Science.gov (United States)

    Zhai, Chunyang; Zhu, Xiaosong; Lan, Pengfei; Wang, Feng; He, Lixin; Shi, Wenjing; Li, Yang; Li, Min; Zhang, Qingbin; Lu, Peixiang

    2017-03-01

    High-order-harmonic generation in the interaction of femtosecond lasers with atoms and molecules opens the path to molecular-orbital tomography and to probe the electronic dynamics with attosecond-Ångström resolutions. Molecular-orbital tomography requires both the amplitude and phase of the high-order harmonics. Yet the measurement of phases requires sophisticated techniques and represents formidable challenges at present. Here we report a scheme, called diffractive molecular-orbital tomography, to retrieve the molecular orbital solely from the amplitude of high-order harmonics without measuring any phase information. We have applied this method to image the molecular orbitals of N2, CO2, and C2H2 . The retrieved orbital is further improved by taking account the correction of Coulomb potential. The diffractive molecular-orbital tomography scheme, removing the roadblock of phase measurement, significantly simplifies the molecular-orbital tomography procedure and paves an efficient and robust way to the imaging of more complex molecules.

  9. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong

    2015-01-01

    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  10. Distributed nonlinear optical response

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov

    2005-01-01

    The purpose of the research presented here is to investigate basic physical properties in nonlinear optical materials with delayed or nonlocal nonlinearity. Soliton propagation, spectral broadening and the influence of the nonlocality or delay of the nonlinearity are the main focusses in the work...

  11. Noncommutative Nonlinear Supersymmetry

    CERN Document Server

    Nishino, H; Nishino, Hitoshi; Rajpoot, Subhash

    2002-01-01

    We present noncommutative nonlinear supersymmetric theories. The first example is a non-polynomial Akulov-Volkov-type lagrangian with noncommutative nonlinear global supersymmetry in arbitrary space-time dimensions. The second example is the generalization of this lagrangian to Dirac-Born-Infeld lagrangian with nonlinear supersymmetry realized in dimensions D=2,3,4 and 6 (mod 8).

  12. Fiber Nonlinearities: A Tutorial

    Institute of Scientific and Technical Information of China (English)

    Govind P. Agrawal

    2003-01-01

    Fiber nonlinearities have long been regarded as being mostly harmful for fiber-optic communication systems. Over the last few years, however, the nonlinear effects are increasingly being used for practical telecommunications applications,the Raman amplification being only one of the recent examples. In this tutorial I review the vario us nonlinear effects occurring in optical fibers from both standpoints..

  13. Fiber Nonlinearities: A Tutorial

    Institute of Scientific and Technical Information of China (English)

    Govind; P.; Agrawal

    2003-01-01

    Fiber nonlinearities have long been regarded as being mostly harmful for fiber-optic communication systems. Over the last few years, however, the nonlinear effects are increasingly being used for practical telecommunications applications, the Raman amplification being only one of the recent examples. In this tutorial I review the various nonlinear effects occurring in optical fibers from both standpoints..

  14. PBH tests for nonlinear systems

    NARCIS (Netherlands)

    Kawano, Yu; Ohtsuka, Toshiyuki

    2017-01-01

    Recently, concepts of nonlinear eigenvalues and eigenvectors are introduced. In this paper, we establish connections between the nonlinear eigenvalues and nonlinear accessibility/observability. In particular, we provide a generalization of Popov- Belevitch-Hautus (PBH) test to nonlinear accessibilit

  15. Can Kinematic Diffraction Distinguish Order from Disorder?

    CERN Document Server

    Baake, Michael

    2008-01-01

    Diffraction methods are at the heart of structure determination of solids. While Bragg-like scattering (pure point diffraction) is a characteristic feature of crystals and quasicrystals, it is not straightforward to interpret continuous diffraction intensities, which are generally linked to the presence of disorder. However, based on simple model systems, we demonstrate that it may be impossible to draw conclusions on the degree of order in the system from its diffraction image. In particular, we construct a family of one-dimensional binary systems which cover the entire entropy range but still share the same purely diffuse diffraction spectrum.

  16. Advances in structure research by diffraction methods

    CERN Document Server

    Brill, R

    1970-01-01

    Advances in Structure Research by Diffraction Methods reviews advances in the use of diffraction methods in structure research. Topics covered include the dynamical theory of X-ray diffraction, with emphasis on Ewald waves in theory and experiment; dynamical theory of electron diffraction; small angle scattering; and molecular packing. This book is comprised of four chapters and begins with an overview of the dynamical theory of X-ray diffraction, especially in terms of how it explains all the absorption and propagation properties of X-rays at the Bragg setting in a perfect crystal. The next

  17. Advances in structure research by diffraction methods

    CERN Document Server

    Hoppe, W

    1974-01-01

    Advances in Structure Research by Diffraction Methods: Volume 5 presents discussions on application of diffraction methods in structure research. The book provides the aspects of structure research using various diffraction methods. The text contains 2 chapters. Chapter 1 reviews the general theory and experimental methods used in the study of all types of amorphous solid, by both X-ray and neutron diffraction, and the detailed bibliography of work on inorganic glasses. The second chapter discusses electron diffraction, one of the major methods of determining the structures of molecules in the

  18. Nonlinear dynamics and complexity

    CERN Document Server

    Luo, Albert; Fu, Xilin

    2014-01-01

    This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.

  19. The optical length effect, diffraction pattern and thermal lensing of Disperse Orange 25

    Science.gov (United States)

    Salmani, S.; Ara, M. H. Majles

    2016-08-01

    The nonlinear responses of an azo dye, Disperse Orange 25 (DO25), are investigated under two irradiation of continuous Lasers at 532 and 632 nm wavelengths and the third order refractive index is measured by use of Z-scan technique. At 632 nm wavelength (far from the absorption peak), the close z-scan plots show that this material has a very good nonlinear response with negative sign indicating self-defocusing. The effect of optical length and concentration of samples in nonlinear responses have been investigated experimentally. Also, the radius variation at far field observed due to thermal lens effect. Finally, at other wavelength, 532 nm (near from the absorption peak), the nonlinear optical responses increase sharply so the diffraction rings appear and the numbers of rings increase with the incident laser power.

  20. Diffraction tomography with Fourier ptychography

    CERN Document Server

    Horstmeyer, Roarke

    2015-01-01

    This article presents a method to perform diffraction tomography in a standard microscope that includes an LED array for illumination. After acquiring a sequence of intensity-only images of a thick sample, a ptychography-based reconstruction algorithm solves for its unknown complex index of refraction across three dimensions. The experimental microscope demonstrates a spatial resolution of 0.39 $\\mu$m and an axial resolution of 3.7 $\\mu$m at the Nyquist-Shannon sampling limit (0.54 $\\mu$m and 5.0 $\\mu$m at the Sparrow limit, respectively), across a total imaging volume of 2.2 mm $\\times$ 2.2 mm $\\times$ 110 $\\mu$m. Unlike competing methods, the 3D tomograms presented in this article are continuous, quantitative, and formed without the need for interferometry or any moving parts. Wide field-of-view reconstructions of thick biological specimens demonstrate potential applications in pathology and developmental biology.

  1. Diffractive X-Ray Telescopes

    Science.gov (United States)

    Skinner, Gerald K.

    2010-01-01

    Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  2. Diffractive X-ray Telescopes

    CERN Document Server

    Skinner, Gerald K

    2010-01-01

    Diffractive X-ray telescopes using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution several orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted space- time in the immediate vicinity of the super-massive black holes in the center of active galaxies What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

  3. Photo-imprint Photoacoustic Microscopy for Three-dimensional Label-free Sub-diffraction Imaging

    Science.gov (United States)

    Yao, Junjie; Wang, Lidai; Li, Chiye; Zhang, Chi; Wang, Lihong V.

    2014-01-01

    Sub-diffraction optical microscopy allows the imaging of cellular and subcellular structures with resolution finer than the diffraction limit. Here, combining the absorption-based photoacoustic effect and intensity-dependent photobleaching effect, we demonstrate a simple method for sub-diffraction photoacoustic imaging of both fluorescent and non-fluorescent samples. Our method is based on a double-excitation process, where the first excitation pulse partially and inhomogeneously bleaches the molecules in the diffraction-limited excitation volume, thus biasing the signal contributions from a second excitation pulse striking the same region. The differential signal between the two excitations preserves the signal contribution mostly from the center of the excitation volume, and dramatically sharpens the lateral resolution. Moreover, due to the nonlinear nature of the signal, our method offers inherent optical sectioning capability, which is lacking in conventional photoacoustic microscopy. By scanning the excitation beam, we performed three-dimensional sub-diffraction imaging of varied fluorescent and non-fluorescent species. As any molecules have absorption, this technique has the potential to enable label-free sub-diffraction imaging, and can be transferred to other optical imaging modalities or combined with other sub-diffraction methods. PMID:24483902

  4. A seismic diffraction extraction method for the study of discontinuous geologies using a regularisation algorithm

    Science.gov (United States)

    Yu, Caixia; Wang, Yanfei; Zhao, Jingtao

    2017-10-01

    Seismic diffractions play a vital role in identifying discontinuous geological structures, such as tiny faults and cavities which are important because of their close relationship with the reservoir properties of oil and gas. In this paper, we focus on an extraction method for separation of seismic diffractions. The energy of reflection is usually much stronger than that of the diffraction, thus, removing reflection becomes a key problem for diffraction applications. In order to extract seismic diffractions accurately and stably, we propose an optimised regularisation method based on the local plane-wave equation. By considering two constraints arising from the Sobolev penalty function and the difference operator, we build a stable minimisation model for determining seismic slopes. In computation, an iterative method based on projection onto a convex set for solving the nonlinear minimisation is developed, which can provide fast and accurate solutions. Subtracting the predicted reflections from the seismic image, we can extract the seismic diffractions. Numerical experiments illustrate the effectiveness of the diffraction extraction method in separating tiny faults, scatterers and cavities. Finally, a carbonate reservoir field example is provided to demonstrate the high-resolution capability of the method in revealing small-scale discontinuous geological features.

  5. Investigation of diffractive optical element femtosecond laser machining

    Energy Technology Data Exchange (ETDEWEB)

    Chabrol, Grégoire R., E-mail: g.chabrol@ecam-strasbourg.eu [ECAM Strasbourg-Europe, Espace Européen de l’entreprise, 2, rue de Madrid – 67300 SCHILTIGHEIM, CS. 20013, 67012 Strasbourg CEDEX (France); Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7357, 300 bld Sébastien Brant, CS 10413, 67412 Illkirch cedex (France); Ciceron, Adline [ECAM Strasbourg-Europe, Espace Européen de l’entreprise, 2, rue de Madrid – 67300 SCHILTIGHEIM, CS. 20013, 67012 Strasbourg CEDEX (France); Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7357, 300 bld Sébastien Brant, CS 10413, 67412 Illkirch cedex (France); Twardowski, Patrice; Pfeiffer, Pierre [Laboratoire des Sciences de l’Ingénieur, de l’Informatique et de l’Imagerie (ICube), UDS-CNRS, UMR 7357, 300 bld Sébastien Brant, CS 10413, 67412 Illkirch cedex (France); Télécom Physique Strasbourg – Pôle API – 300 Bd Sébastien Brant – CS 10413, Illkirch Graffenstaden F 67400 (France); and others

    2016-06-30

    Highlights: • A method for rapid manufacturing of optical diffractive element in BK7 is proposed. • A binary grating in BK7 was successfully machined by femtosecond laser pulses. • Process relying on nonlinear absorption in the dielectric due to photoionization. • The binary grating was analysed by SEM and interferometric microscopy. • Simulations by Fourier modal method supported the measured diffractive efficiency. - Abstract: This paper presents an explorative study on the machining of diffractive optical elements (DOEs) in transparent materials using a femtosecond laser source. A simple form of DOE, a binary phase grating with a period of 20.85 μm (σ = 0.5 μm), a groove depth and width of 0.7 μm (σ = 0.2 μm) and 8.8 μm (σ = 0.5 μm) respectively, was successfully machined in BK7. The topographic characteristics were measured by white light interferometry and scanning electron microscopy (SEM). The processing was carried out on high precision stages with an ultrafast fibre laser (350 fs) emitting a 343 nm pulse focused onto the sample with a stationary microscope objective. A diffracted efficiency of 27%, obtained with a spectro goniometer, was corroborated by the theoretical results obtained by the Fourier modal method (FMM), taking into account the measured topographic values. These encouraging results demonstrate that high-speed femtosecond laser manufacturing of DOE in bulk glasses can be achieved, opening the way to rapid prototyping of multi-layered-DOEs.

  6. Nonlinear Elliptic Differential Equations with Multivalued Nonlinearities

    Indian Academy of Sciences (India)

    Antonella Fiacca; Nikolaos Matzakos; Nikolaos S Papageorgiou; Raffaella Servadei

    2001-11-01

    In this paper we study nonlinear elliptic boundary value problems with monotone and nonmonotone multivalued nonlinearities. First we consider the case of monotone nonlinearities. In the first result we assume that the multivalued nonlinearity is defined on all $\\mathbb{R}$. Assuming the existence of an upper and of a lower solution, we prove the existence of a solution between them. Also for a special version of the problem, we prove the existence of extremal solutions in the order interval formed by the upper and lower solutions. Then we drop the requirement that the monotone nonlinearity is defined on all of $\\mathbb{R}$. This case is important because it covers variational inequalities. Using the theory of operators of monotone type we show that the problem has a solution. Finally in the last part we consider an eigenvalue problem with a nonmonotone multivalued nonlinearity. Using the critical point theory for nonsmooth locally Lipschitz functionals we prove the existence of at least two nontrivial solutions (multiplicity theorem).

  7. Hard diffraction with dynamic gap survival

    Science.gov (United States)

    Rasmussen, Christine O.; Sjöstrand, Torbjörn

    2016-02-01

    We present a new framework for the modelling of hard diffraction in pp and poverline{p} collisions. It starts from the the approach pioneered by Ingelman and Schlein, wherein the single diffractive cross section is factorized into a Pomeron flux and a Pomeron PDF. To this it adds a dynamically calculated rapidity gap survival factor, derived from the modelling of multiparton interactions. This factor is not relevant for diffraction in ep collisions, giving non-universality between HERA and Tevatron diffractive event rates. The model has been implemented in P ythia 8 and provides a complete description of the hadronic state associated with any hard single diffractive process. Comparisons with poverline{p} and pp data reveal improvement in the description of single diffractive events.

  8. Diffraction Correlation to Reconstruct Highly Strained Particles

    Science.gov (United States)

    Brown, Douglas; Harder, Ross; Clark, Jesse; Kim, J. W.; Kiefer, Boris; Fullerton, Eric; Shpyrko, Oleg; Fohtung, Edwin

    2015-03-01

    Through the use of coherent x-ray diffraction a three-dimensional diffraction pattern of a highly strained nano-crystal can be recorded in reciprocal space by a detector. Only the intensities are recorded, resulting in a loss of the complex phase. The recorded diffraction pattern therefore requires computational processing to reconstruct the density and complex distribution of the diffracted nano-crystal. For highly strained crystals, standard methods using HIO and ER algorithms are no longer sufficient to reconstruct the diffraction pattern. Our solution is to correlate the symmetry in reciprocal space to generate an a priori shape constraint to guide the computational reconstruction of the diffraction pattern. This approach has improved the ability to accurately reconstruct highly strained nano-crystals.

  9. Hard Diffraction with Dynamic Gap Survival

    CERN Document Server

    Rasmussen, Christine O

    2015-01-01

    We present a new framework for the modelling of hard diffraction in pp and ppbar collisions. It starts from the the approach pioneered by Ingelman and Schlein, wherein the single diffractive cross section is factorized into a Pomeron flux and a Pomeron PDF. To this it adds a dynamically calculated rapidity gap survival factor, derived from the modelling of multiparton interactions. This factor is not relevant for diffraction in ep collisions, giving non-universality between HERA and Tevatron diffractive event rates. The model has been implemented in Pythia 8 and provides a complete description of the hadronic state associated with any hard single diffractive process. Comparisons with ppbar and pp data reveal improvement in the description of single diffractive events.

  10. Application of an approximate vectorial diffraction model to analysing diffractive micro-optical elements

    Institute of Scientific and Technical Information of China (English)

    Niu Chun-Hui; Li Zhi-Yuan; Ye Jia-Sheng; Gu Ben-Yuan

    2005-01-01

    Scalar diffraction theory, although simple and efficient, is too rough for analysing diffractive micro-optical elements.Rigorous vectorial diffraction theory requires extensive numerical efforts, and is not a convenient design tool. In this paper we employ a simple approximate vectorial diffraction model which combines the principle of the scalar diffraction theory with an approximate local field model to analyse the diffraction of optical waves by some typical two-dimensional diffractive micro-optical elements. The TE and TM polarization modes are both considered. We have found that the approximate vectorial diffraction model can agree much better with the rigorous electromagnetic simulation results than the scalar diffraction theory for these micro-optical elements.

  11. Nonlinear Dirac Equations

    Directory of Open Access Journals (Sweden)

    Wei Khim Ng

    2009-02-01

    Full Text Available We construct nonlinear extensions of Dirac's relativistic electron equation that preserve its other desirable properties such as locality, separability, conservation of probability and Poincaré invariance. We determine the constraints that the nonlinear term must obey and classify the resultant non-polynomial nonlinearities in a double expansion in the degree of nonlinearity and number of derivatives. We give explicit examples of such nonlinear equations, studying their discrete symmetries and other properties. Motivated by some previously suggested applications we then consider nonlinear terms that simultaneously violate Lorentz covariance and again study various explicit examples. We contrast our equations and construction procedure with others in the literature and also show that our equations are not gauge equivalent to the linear Dirac equation. Finally we outline various physical applications for these equations.

  12. High-energy electron diffraction and microscopy

    CERN Document Server

    Peng, L M; Whelan, M J

    2011-01-01

    This book provides a comprehensive introduction to high energy electron diffraction and elastic and inelastic scattering of high energy electrons, with particular emphasis on applications to modern electron microscopy. Starting from a survey of fundamental phenomena, the authors introduce the most important concepts underlying modern understanding of high energy electron diffraction. Dynamical diffraction in transmission (THEED) and reflection (RHEED) geometries is treated using ageneral matrix theory, where computer programs and worked examples are provided to illustrate the concepts and to f

  13. CMS results on soft and hard diffraction

    CERN Document Server

    Obertino, Margherita Maria

    2016-01-01

    The measurement of the soft diffractive cross sections in single- and double-diffractive final states is presented at 7 TeV. Furthermore, also the production of jet-gap-get final states is discussed and the results are interpreted in terms of a hard color singlet exchange. Finally, general features of particle production in single-diffractive enhanced events are shown at 13 TeV.

  14. Spectral Anomalies in the Fraunhofer Diffraction Pattern

    Institute of Scientific and Technical Information of China (English)

    PU Ji-Xiong; CAI Chao; HU Xian-Dai; LIU Xiao-Yun

    2005-01-01

    @@ We study the spectral characteristics theoretically and experimentally in the Fraunhofer diffraction pattern formed by the diffraction of a spatially coherent, polychromatic light through a slit. It is found that the spectrum in some diffraction directions close to the singular direction is redshifted, compared to the spectrum of the incident polychromatic light, and blueshifted in other directions, and splits into two lines at the singular direction. We show that the experimental results are consistent with the theoretical expectations.

  15. Calculation of Loudspeaker Cabinet Diffraction and Correction

    Institute of Scientific and Technical Information of China (English)

    LE Yi; SHEN Yong; XIA Jie

    2011-01-01

    A method of calculating the cabinet edge diffractions for loudspeaker driver when mounted in an enclosure is proposed,based on the extended Biot-Tolstoy-Medwin model.Up to the third order,cabinet diffractions are discussed in detail and the diffractive effects on the radiated sound field of the loudspeaker system are quantitatively described,with a correction function built to compensate for the diffractive interference.The method is applied to a practical loudspeaker enclosure that has rectangular facets.The diffractive effects of the cabinet on the forward sound radiation are investigated and predictions of the calculations show quite good agreements with experimental measurements.Most loudspeaker systems employ box-like cabinets.The response of a loudspeaker mounted in a box is much rougher than that of the same driver mounted on a large baffle.Although resonances in the box are partly responsible for the lack of smoothness,a major contribution is the diffraction of the cabinet edges,which aggravates the final response performance.Consequently,an analysis of the cabinet diffraction problem is required.%A method of calculating the cabinet edge diffractions for loudspeaker driver when mounted in an enclosure is proposed, based on the extended Biot-Tolstoy-Medwin model. Up to the third order, cabinet diffractions are discussed in detail and the diffractive effects on the radiated sound field of the loudspeaker system are quantitatively described, with a correction function built to compensate for the diffractive interference. The method is applied to a practical loudspeaker enclosure that has rectangular facets. The diffractive effects of the cabinet on the forward sound radiation are investigated and predictions of the calculations show quite good agreements with experimental measurements.

  16. Theory of edge diffraction in electromagnetics

    CERN Document Server

    Ufimtsev, Pyotr

    2009-01-01

    This book is an essential resource for researchers involved in designing antennas and RCS calculations. It is also useful for students studying high frequency diffraction techniques. It contains basic original ideas of the Physical Theory of Diffraction (PTD), examples of its practical application, and its validation by the mathematical theory of diffraction. The derived analytic expressions are convenient for numerical calculations and clearly illustrate the physical structure of the scattered field.

  17. Advances in powder diffraction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Louer, D. [Lab. de Chimie du Solide et Inorganique Moleculaire, Rennes (France). Groupe de Cristallochimie

    1998-11-01

    Powder diffraction offers a wide spectrum of applications to solid-state scientists. The method traditionally used for phase analysis and the study of structural imperfections has benefited, in the last twenty years, from great advances in the instrumentation and computer-based approaches for pattern indexing and modelling. The factors at the origin of the metamorphosis of the method are presented. The major modern applications reported include quantitative analysis and the extraction of three-dimensional structural and microstructural properties. The use of pattern-fitting techniques for the characterization of the microstructure is discussed through applications to nanocrystalline materials. Remarkable results achieved in the solution of crystal structures are presented, as well as the impact in solid-state chemistry of powder crystallography, particularly for elucidating the crystal chemistry of families of compounds for which only powders are available. New strategies for solving the phase problem have been introduced and new classes of solids are being studied, such as drugs, coordination and organic compounds. (orig.) 100 refs.

  18. Sub-wavelength diffractive optics

    Energy Technology Data Exchange (ETDEWEB)

    Warren, M.E.; Wendt, J.R.; Vawter, G.A.

    1998-03-01

    This report represents the completion of a three-year Laboratory-Directed Research and Development (LDRD) program to investigate sub-wavelength surface relief structures fabricated by direct-write e-beam technology as unique and very high-efficiency optical elements. A semiconductor layer with sub-wavelength sized etched openings or features can be considered as a layer with an effective index of refraction determined by the fraction of the surface filled with semiconductor relative to the fraction filled with air or other material. Such as a layer can be used to implement planar gradient-index lenses on a surface. Additionally, the nanometer-scale surface structures have diffractive properties that allow the direct manipulation of polarization and altering of the reflective properties of surfaces. With this technology a single direct-write mask and etch can be used to integrate a wide variety of optical functions into a device surface with high efficiencies; allowing for example, direct integration of polarizing optics into the surface with high efficiencies; allowing for example, direct integration of polarizing optics into the surfaces of devices, forming anti-reflection surfaces or fabricating high-efficiency, high-numerical aperture lenses, including integration inside vertical semiconductor laser cavities.

  19. Nonlinear Cross Gramians

    Science.gov (United States)

    Ionescu, Tudor C.; Scherpen, Jacquelien M. A.

    We study the notion of cross Gramians for nonlinear gradient systems, using the characterization in terms of prolongation and gradient extension associated to the system. The cross Gramian is given for the variational system associated to the original nonlinear gradient system. We obtain linearization results that correspond to the notion of a cross Gramian for symmetric linear systems. Furthermore, first steps towards relations with the singular value functions of the nonlinear Hankel operator are studied and yield promising results.

  20. Nonlinear functional analysis

    Directory of Open Access Journals (Sweden)

    W. L. Fouché

    1983-03-01

    Full Text Available In this article we discuss some aspects of nonlinear functional analysis. It included reviews of Banach’s contraction theorem, Schauder’s fixed point theorem, globalising techniques and applications of homotopy theory to nonlinear functional analysis. The author emphasises that fundamentally new ideas are required in order to achieve a better understanding of phenomena which contain both nonlinear and definite infinite dimensional features.

  1. Nonlinear Electrodynamics and QED

    OpenAIRE

    2003-01-01

    The limits of linear electrodynamics are reviewed, and possible directions of nonlinear extension are explored. The central theme is that the qualitative character of the empirical successes of quantum electrodynamics must be used as a guide for understanding the nature of the nonlinearity of electrodynamics at the subatomic level. Some established theories of nonlinear electrodynamics, namely, those of Mie, Born, and Infeld are presented in the language of the modern geometrical and topologi...

  2. Diffractive lenses recorded in absorbent photopolymers.

    Science.gov (United States)

    Fernández, R; Gallego, S; Márquez, A; Francés, J; Navarro-Fuster, V; Pascual, I

    2016-01-25

    Photopolymers can be appealing materials for diffractive optical elements fabrication. In this paper, we present the recording of diffractive lenses in PVA/AA (Polyvinyl alcohol acrylamide) based photopolymers using a liquid crystal device as a master. In addition, we study the viability of using a diffusion model to simulate the lens formation in the material and to study the influence of the different parameters that govern the diffractive formation in photopolymers. Once we control the influence of each parameter, we can fit an optimum recording schedule to record each different diffractive optical element with the optimum focalization power.

  3. Nonlinear plasmonic imaging techniques and their biological applications

    Science.gov (United States)

    Deka, Gitanjal; Sun, Chi-Kuang; Fujita, Katsumasa; Chu, Shi-Wei

    2017-01-01

    Nonlinear optics, when combined with microscopy, is known to provide advantages including novel contrast, deep tissue observation, and minimal invasiveness. In addition, special nonlinearities, such as switch on/off and saturation, can enhance the spatial resolution below the diffraction limit, revolutionizing the field of optical microscopy. These nonlinear imaging techniques are extremely useful for biological studies on various scales from molecules to cells to tissues. Nevertheless, in most cases, nonlinear optical interaction requires strong illumination, typically at least gigawatts per square centimeter intensity. Such strong illumination can cause significant phototoxicity or even photodamage to fragile biological samples. Therefore, it is highly desirable to find mechanisms that allow the reduction of illumination intensity. Surface plasmon, which is the collective oscillation of electrons in metal under light excitation, is capable of significantly enhancing the local field around the metal nanostructures and thus boosting up the efficiency of nonlinear optical interactions of the surrounding materials or of the metal itself. In this mini-review, we discuss the recent progress of plasmonics in nonlinear optical microscopy with a special focus on biological applications. The advancement of nonlinear imaging modalities (including incoherent/coherent Raman scattering, two/three-photon luminescence, and second/third harmonic generations that have been amalgamated with plasmonics), as well as the novel subdiffraction limit imaging techniques based on nonlinear behaviors of plasmonic scattering, is addressed.

  4. Nonlinear plasmonic imaging techniques and their biological applications

    Directory of Open Access Journals (Sweden)

    Deka Gitanjal

    2016-07-01

    Full Text Available Nonlinear optics, when combined with microscopy, is known to provide advantages including novel contrast, deep tissue observation, and minimal invasiveness. In addition, special nonlinearities, such as switch on/off and saturation, can enhance the spatial resolution below the diffraction limit, revolutionizing the field of optical microscopy. These nonlinear imaging techniques are extremely useful for biological studies on various scales from molecules to cells to tissues. Nevertheless, in most cases, nonlinear optical interaction requires strong illumination, typically at least gigawatts per square centimeter intensity. Such strong illumination can cause significant phototoxicity or even photodamage to fragile biological samples. Therefore, it is highly desirable to find mechanisms that allow the reduction of illumination intensity. Surface plasmon, which is the collective oscillation of electrons in metal under light excitation, is capable of significantly enhancing the local field around the metal nanostructures and thus boosting up the efficiency of nonlinear optical interactions of the surrounding materials or of the metal itself. In this mini-review, we discuss the recent progress of plasmonics in nonlinear optical microscopy with a special focus on biological applications. The advancement of nonlinear imaging modalities (including incoherent/coherent Raman scattering, two/three-photon luminescence, and second/third harmonic generations that have been amalgamated with plasmonics, as well as the novel subdiffraction limit imaging techniques based on nonlinear behaviors of plasmonic scattering, is addressed.

  5. Nonlinear Physics of Plasmas

    CERN Document Server

    Kono, Mitsuo

    2010-01-01

    A nonlinearity is one of the most important notions in modern physics. A plasma is rich in nonlinearities and provides a variety of behaviors inherent to instabilities, coherent wave structures and turbulence. The book covers the basic concepts and mathematical methods, necessary to comprehend nonlinear problems widely encountered in contemporary plasmas, but also in other fields of physics and current research on self-organized structures and magnetized plasma turbulence. The analyses make use of strongly nonlinear models solved by analytical techniques backed by extensive simulations and available experiments. The text is written for senior undergraduates, graduate students, lecturers and researchers in laboratory, space and fusion plasmas.

  6. Nonlinear magnetic metamaterials.

    Science.gov (United States)

    Shadrivov, Ilya V; Kozyrev, Alexander B; van der Weide, Daniel W; Kivshar, Yuri S

    2008-12-08

    We study experimentally nonlinear tunable magnetic metamaterials operating at microwave frequencies. We fabricate the nonlinear metamaterial composed of double split-ring resonators where a varactor diode is introduced into each resonator so that the magnetic resonance can be tuned dynamically by varying the input power. We demonstrate that at higher powers the transmission of the metamaterial becomes power-dependent and, as a result, such metamaterial can demonstrate various nonlinear properties. In particular, we study experimentally the power-dependent shift of the transmission band and demonstrate nonlinearity-induced enhancement (or suppression) of wave transmission. (c) 2008 Optical Society of America

  7. Organic nonlinear optical materials

    Science.gov (United States)

    Umegaki, S.

    1987-01-01

    Recently, it became clear that organic compounds with delocalized pi electrons show a great nonlinear optical response. Especially, secondary nonlinear optical constants of more than 2 digits were often seen in the molecular level compared to the existing inorganic crystals such as LiNbO3. The crystallization was continuously tried. Organic nonlinear optical crystals have a new future as materials for use in the applied physics such as photomodulation, optical frequency transformation, opto-bistabilization, and phase conjugation optics. Organic nonlinear optical materials, e.g., urea, O2NC6H4NH2, I, II, are reviewed with 50 references.

  8. Nonlinearity-reduced interferometer

    Science.gov (United States)

    Wu, Chien-ming

    2007-12-01

    Periodic nonlinearity is a systematic error limiting the accuracy of displacement measurements at the nanometer level. It results from many causes such as the frequency mixing, polarization mixing, polarization-frequency mixing, and the ghost reflections. An interferometer having accuracy in displacement measurement of less than one-nanometer is necessary in nanometrology. To meet the requirement, the periodic nonlinearity should be less than deep sub-nanometer. In this paper, a nonlinearity-reduced interferometry has been proposed. Both the linear- and straightness-interferometer were tested. The developed interferometer demonstrated of a residual nonlinearity less than 25 pm.

  9. The Nonlinear Talbot Effect of Rogue Waves

    CERN Document Server

    Zhang, Yiqi; Zheng, Huaibin; Chen, Haixia; Li, Changbiao; Song, Jianping; Zhang, Yanpeng

    2014-01-01

    Akhmediev and Kuznetsov-Ma breathers are rogue wave solutions of the nonlinear Schr\\"odinger equation (NLSE). Talbot effect (TE) is an image recurrence phenomenon in the diffraction of light waves. We report the nonlinear TE of rogue waves in a cubic medium. It is different from the linear TE, in that the wave propagates in a NL medium and is an eigenmode of NLSE. Periodic rogue waves impinging on a NL medium exhibit recurrent behavior, but only at the TE length and at the half-TE length with a \\pi-phase shift; the fractional TE is absent. The NL TE is the result of the NL interference of the lobes of rogue wave breathers. This interaction is related to the transverse period and intensity of breathers, in that the bigger the period and the higher the intensity, the shorter the TE length.

  10. Conical wave propagation and diffraction in two-dimensional hexagonally packed granular lattices.

    Science.gov (United States)

    Chong, C; Kevrekidis, P G; Ablowitz, M J; Ma, Yi-Ping

    2016-01-01

    Linear and nonlinear mechanisms for conical wave propagation in two-dimensional lattices are explored in the realm of phononic crystals. As a prototypical example, a statically compressed granular lattice of spherical particles arranged in a hexagonal packing configuration is analyzed. Upon identifying the dispersion relation of the underlying linear problem, the resulting diffraction properties are considered. Analysis both via a heuristic argument for the linear propagation of a wave packet and via asymptotic analysis leading to the derivation of a Dirac system suggests the occurrence of conical diffraction. This analysis is valid for strong precompression, i.e., near the linear regime. For weak precompression, conical wave propagation is still possible, but the resulting expanding circular wave front is of a nonoscillatory nature, resulting from the complex interplay among the discreteness, nonlinearity, and geometry of the packing. The transition between these two types of propagation is explored.

  11. Stress in Thin Films; Diffraction Elastic Constants and Grain Interaction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Untextured bulk polycrystals usually possess macroscopically isotropic elastic properties whereas for most thin films transverse isotropy is expected, owing to the limited dimensionality. The usually applied models for the calculation of elastic constants of polycrystals from single crystal elastic constants (so-called grain interaction models) erroneously predict macroscopic isotropy for an (untextured) thin film. This paper presents a summary of recent work where it has been demonstrated for the first time by X-ray diffraction analysis of stresses in thin films that elastic grain interaction can lead to macroscopically elastically anisotropic behaviour (shown by non-linear sin2ψ plots). A new grain interaction model, predicting the macroscopically anisotropic behaviour of thin films, is proposed.

  12. Single and double diffraction dissociation at the LHC

    Science.gov (United States)

    Fiore, Roberto; Jenkovszky, László; Mieskolainen, Mikael; Orava, Risto

    2017-03-01

    Single and double diffraction dissociation at the LHC is studied in a factorizable Regge-pole model, dominated by a Pomeron pole exchange in the t channel. While the contribution from secondary reggeon exchanges at the LHC is negligible, they are indispensable to match the lower-energy, ISR and FNAL data. To this end we append to the leading Pomeron exchange an effective reggeon. The main emphasis in our study is on the nucleon resonances in missing masses, that are accounted for by a dual model of the inelastic pP → MX vertex, similar to the DIS structure function, known from HERA, with a non-linear nucleon, N∗ trajectory in the direct, MX2 channel. Regge factorization and its breakdown due to a renormalization factor, tempering the energy rise is discussed.

  13. Modifying the optical path in a nonlinear double-slit experiment

    CERN Document Server

    Paltoglou, Vassilis

    2015-01-01

    In this letter, we study a nonlinear interferometric setup based on diffraction rather than beam combining. It consists of a nonlinear analogue of Young's double-slit experiment where a nonlinear material is placed exactly after one of the slits. The presence of nonlinearity breaks the transverse spatial symmetry of the system and thus modifies the optical path. For moderate nonlinearities this leads to a self-induced shift of the intensity pattern in the transverse plane. A simple theoretical model is developed which is surprisingly accurate in predicting the intensity profile of the main lobes for a wide range of parameters. We discuss about possible applications of our model in nonlinear interferometry, for example in measuring the nonlinearities of optical materials.

  14. Laser Induced Nonlinear Optical Properties of Zinc Oxide Thin Film Prepared by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Vinay Kumari

    2011-01-01

    Full Text Available Optical nonlinearities of spin coated ZnO thin film have been investigated by using single beam Z-Scan technique in the visible region. X- ray diffraction shows that all films are oriented along the c-axis direction of the hexagonal crystal structure. The average optical transmittance of all films is higher than 80 %. The nonlinear optical parameters viz. nonlinear absorption coefficient (β, nonlinear index of refraction (η2, nonlinear susceptibility (χ3, have been estimated using nanosecond laser pulses of second harmonic of Nd:YAG Laser. The value of nonlinear absorption coefficient β is estimated to be greater than the already reported value. The films clearly exhibit a-ve value of nonlinear refraction at 532 nm which is attributed to the two photon absorption and free carrier absorption. The presence of RSA in ZnO thin films inferes that ZnO is a potential material for the development of optical limiter.

  15. Numerical modelling of nonlinear full-wave acoustic propagation

    Energy Technology Data Exchange (ETDEWEB)

    Velasco-Segura, Roberto, E-mail: roberto.velasco@ccadet.unam.mx; Rendón, Pablo L., E-mail: pablo.rendon@ccadet.unam.mx [Grupo de Acústica y Vibraciones, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apartado Postal 70-186, C.P. 04510, México D.F., México (Mexico)

    2015-10-28

    The various model equations of nonlinear acoustics are arrived at by making assumptions which permit the observation of the interaction with propagation of either single or joint effects. We present here a form of the conservation equations of fluid dynamics which are deduced using slightly less restrictive hypothesis than those necessary to obtain the well known Westervelt equation. This formulation accounts for full wave diffraction, nonlinearity, and thermoviscous dissipative effects. A two-dimensional, finite-volume method using Roe’s linearisation has been implemented to obtain numerically the solution of the proposed equations. This code, which has been written for parallel execution on a GPU, can be used to describe moderate nonlinear phenomena, at low Mach numbers, in domains as large as 100 wave lengths. Applications range from models of diagnostic and therapeutic HIFU, to parametric acoustic arrays and nonlinear propagation in acoustic waveguides. Examples related to these applications are shown and discussed.

  16. Exclusive Diffraction at HERA and Beyond

    CERN Document Server

    Fazio, S

    2010-01-01

    The exclusive diffractive production of vector mesons and real photons in ep collisions has been studied at HERA in a wide kinematic range. Here the most recent experimental results are presented together with a Regge-type model and projects for new diffractive studies at LHC.

  17. Low mass diffractive systems at LHC

    CERN Document Server

    Schicker, R

    2008-01-01

    A rapidity gap trigger for the ALICE detector at the Large Hadron Collider LHC is presented and a few selected physics observables are discussed. First, some properties of double pomeron events are outlined. Second, signatures of the odderon in diffractive J/Psi production is discussed. Third, possible evidence of gluon saturation in the cross section of diffractive heavy quark photoproduction is investigated.

  18. ATLAS results on diffraction and forward physics

    CERN Document Server

    Tasevsky, M; The ATLAS collaboration

    2014-01-01

    Report on activity in the field of diffraction and forward physics in the ATLAS experiment is given. Results from four analyses are discussed, namely based on diffractively enhanced events by vetoing one side of detector, on soft events with rapidity gaps, on events with jet vetoes and on total cross section measurement by the ALFA subdetector.

  19. Diffractive Optics of Anisotropic Polarization Gratings

    NARCIS (Netherlands)

    Xu, M.

    2009-01-01

    Diffraction gratings are being used to manipulate light in many different applications, such as in flat panel display systems, modern lighting systems, and optical recording. Diffraction gratings can be made polarization selective due to form birefringence. An alternative approach to polarization

  20. Hard Diffraction at D{phi}

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Gilvan A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias

    2000-07-01

    Full text follows: We review recent Hard Diffraction results from the D{phi} experiment at Fermilab, for the following processes: hard color singlet exchange, hard single diffraction, and hard double pomeron exchange. Measurements of rates, {eta}, E{sub T} and {radical}S dependencies are presented and comparisons made with predictions of several models. (author)

  1. White-Light Diffraction with a CD

    Science.gov (United States)

    Ivanov, Dragia Trifonov; Nikolaev, Stefan

    2010-01-01

    Various wave optics experiments can be carried out using an ordinary compact disc. The CD is suitable for use as a diffraction grating. For instance, a standard CD (700 MB) has 625 lines/mm. In this article, the authors describe two white-light diffraction demonstrations for a large audience, realizable using a CD (as reflection or transmission…

  2. Generalized upper bound for inelastic diffraction

    Science.gov (United States)

    Troshin, S. M.; Tyurin, N. E.

    2017-01-01

    For inelastic diffraction, we obtain an upper bound valid for the whole range of the elastic scattering amplitude variation allowed by unitarity. We discuss the energy dependence of the inelastic diffractive cross-section on the base of this bound and recent Large Hadron Collider (LHC) data.

  3. A generalized upper bound for inelastic diffraction

    CERN Document Server

    Troshin, S M

    2016-01-01

    For the inelastic diffraction, we obtain an upper bound valid in the whole range of the elastic scattering amplitude variation allowed by unitarity. We discuss the energy dependence of the inelastic diffractive cross-section on the base of this bound and recent LHC data.

  4. Accurate Charge Densities from Powder Diffraction

    DEFF Research Database (Denmark)

    Bindzus, Niels; Wahlberg, Nanna; Becker, Jacob;

    Synchrotron powder X-ray diffraction has in recent years advanced to a level, where it has become realistic to probe extremely subtle electronic features. Compared to single-crystal diffraction, it may be superior for simple, high-symmetry crystals owing to negligible extinction effects and minimal...... of conventional and novel extraction methods....

  5. QCD subgroup on diffractive and forward physics

    Energy Technology Data Exchange (ETDEWEB)

    Albrow, M.G.; Baker, W.; Bhatti, A. [and others

    1996-10-01

    The goal is to understand the pomeron, and hence the behavior of total cross sections, elastic scattering and diffractive excitation, in terms of the underlying theory, QCD. A description of the basic ideas and phenomenology is followed by a discussion of hadron-hadron and electron-proton experiments. An appendix lists recommended diffractive-physics terms and definitions. 44 refs., 6 figs.

  6. Lasers for nonlinear microscopy.

    Science.gov (United States)

    Wise, Frank

    2013-03-01

    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

  7. Nonlinear optical materials.

    Science.gov (United States)

    Eaton, D F

    1991-07-19

    The current state of materials development in nonlinear optics is summarized, and the promise of these materials is critically evaluated. Properties and important materials constants of current commercial materials and of new, promising, inorganic and organic molecular and polymeric materials with potential in second- and third-order nonlinear optical applications are presented.

  8. Estimating nonlinear models

    Science.gov (United States)

    Billings, S. A.

    1988-03-01

    Time and frequency domain identification methods for nonlinear systems are reviewed. Parametric methods, prediction error methods, structure detection, model validation, and experiment design are discussed. Identification of a liquid level system, a heat exchanger, and a turbocharge automotive diesel engine are illustrated. Rational models are introduced. Spectral analysis for nonlinear systems is treated. Recursive estimation is mentioned.

  9. Nonlinear Cross Gramians

    NARCIS (Netherlands)

    Ionescu, T. C.; Scherpen, J. M. A.; Korytowski, A; Malanowski, K; Mitkowski, W; Szymkat, M

    2009-01-01

    We study the notion of cross Gramians for nonlinear gradient systems, using the characterization in terms of prolongation and gradient extension associated to the system. The cross Gramian is given for the variational system associated to the original nonlinear gradient system. We obtain

  10. Engineered nonlinear lattices

    DEFF Research Database (Denmark)

    Clausen, Carl A. Balslev; Christiansen, Peter Leth; Torner, L.

    1999-01-01

    We show that with the quasi-phase-matching technique it is possible to fabricate stripes of nonlinearity that trap and guide light like waveguides. We investigate an array of such stripes and find that when the stripes are sufficiently narrow, the beam dynamics is governed by a quadratic nonlinear...

  11. Controllability in nonlinear systems

    Science.gov (United States)

    Hirschorn, R. M.

    1975-01-01

    An explicit expression for the reachable set is obtained for a class of nonlinear systems. This class is described by a chain condition on the Lie algebra of vector fields associated with each nonlinear system. These ideas are used to obtain a generalization of a controllability result for linear systems in the case where multiplicative controls are present.

  12. Nonlinear Maneuver Autopilot

    Science.gov (United States)

    Menon, P. K. A.; Badgett, M. E.; Walker, R. A.

    1992-01-01

    Trajectory-control laws based on singular-perturbation theory and nonlinear dynamical modeling. Nonlinear maneuver autopilot commands flight-test trajectories of F-15 airplane. Underlying theory of controller enables separation of variables processed in fast and slow control loops, reducing amount of computation required.

  13. Uniting Electron Crystallography and Powder Diffraction

    CERN Document Server

    Shankland, Kenneth; Meshi, Louisa; Avilov, Anatoly; David, William

    2012-01-01

    The polycrystalline and nanocrystalline states play an increasingly important role in exploiting the properties of materials, encompassing applications as diverse as pharmaceuticals, catalysts, solar cells and energy storage. A knowledge of the three-dimensional atomic and molecular structure of materials is essential for understanding and controlling their properties, yet traditional single-crystal X-ray diffraction methods lose their power when only polycrystalline and nanocrystalline samples are available. It is here that powder diffraction and single-crystal electron diffraction techniques take over, substantially extending the range of applicability of the crystallographic principles of structure determination.  This volume, a collection of teaching contributions presented at the Crystallographic Course in Erice in 2011, clearly describes the fundamentals and the state-of-the-art of powder diffraction and electron diffraction methods in materials characterisation, encompassing a diverse range of discipl...

  14. "Good-Walker" + QCD dipoles = Hard Diffraction

    CERN Document Server

    Peschanski, R

    1998-01-01

    The Good-Walker mechanism for diffraction is shown to provide a link between total and diffractive structure functions and to be relevant for QCD calculations at small x_{Bj}. For Deep-Inelastic scattering on a small-size target (cf. an onium) the r\\^ ole of Good-Walker ``diffractive eigenstates'' is played by the QCD dipoles appearing in the $1/N_C$ limit of QCD. Hard diffraction is thus related to the QCD tripe-dipole vertex which has been recently identified (and calculated) as being a conformal invariant correlator and/or a closed-string amplitude. An extension to hard diffraction at HERA via $k_T-$factorisation of the proton vertices leads to interesting phenomenology.

  15. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S

    2015-01-01

    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  16. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo

    2015-01-01

    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  17. Aberration correction for time-domain ultrasound diffraction tomography.

    Science.gov (United States)

    Mast, T Douglas

    2002-07-01

    Extensions of a time-domain diffraction tomography method, which reconstructs spatially dependent sound speed variations from far-field time-domain acoustic scattering measurements, are presented and analyzed. The resulting reconstructions are quantitative images with applications including ultrasonic mammography, and can also be considered candidate solutions to the time-domain inverse scattering problem. Here, the linearized time-domain inverse scattering problem is shown to have no general solution for finite signal bandwidth. However, an approximate solution to the linearized problem is constructed using a simple delay-and-sum method analogous to "gold standard" ultrasonic beamforming. The form of this solution suggests that the full nonlinear inverse scattering problem can be approximated by applying appropriate angle- and space-dependent time shifts to the time-domain scattering data; this analogy leads to a general approach to aberration correction. Two related methods for aberration correction are presented: one in which delays are computed from estimates of the medium using an efficient straight-ray approximation, and one in which delays are applied directly to a time-dependent linearized reconstruction. Numerical results indicate that these correction methods achieve substantial quality improvements for imaging of large scatterers. The parametric range of applicability for the time-domain diffraction tomography method is increased by about a factor of 2 by aberration correction.

  18. Theory of groove-envelope phase effects in self-diffraction

    CERN Document Server

    Reislöhner, Jan; Pfeiffer, Adrian N

    2016-01-01

    If two laser beams cross in a medium under shallow angle, the laser-induced grating consists of only a few grooves. In this situation, the phase between the grooves of the grating and its envelope is a decisive parameter for nonlinear effects. Here, models are established for reproducing the groove-envelope phase effects that have been observed in the interference pattern of self-diffraction. Four-wave mixing leads to interferences that are dominant in the spatial region between the orders of diffraction and with tilted interference fringes in the diagram of transverse coordinate vs. pulse delay. The vertical interference fringes that are dominant directly on the diffraction orders, experimentally observed at high intensity close to the damage threshold, require a model beyond four-wave mixing. A model is suggested that is based on optical transmission changes with confinement to regions in the medium that are smaller than the groove spacing.

  19. Interaction of cylindrically converging diffracted shock with uniform interface

    Science.gov (United States)

    Liang, Yu; Ding, Juchun; Zhai, Zhigang; Si, Ting; Luo, Xisheng

    2017-08-01

    The Richtmyer-Meshkov instability of an unperturbed air/SF6 interface subjected to a diffracted shock is experimentally studied by high-speed schlieren photography under cylindrical circumstances. The cylindrically converging diffracted shock (CCDS) is produced by a cylindrically uniform shock diffracting around a rigid cylinder(s), and the unperturbed interface is created by a soap film technique. The effects of coupling of multiple rigid cylinders and diverse spacings from the cylinder to interface on a flow field are highlighted. Schlieren images indicate that the amplitude of disturbances on the CCDS increases compared with the local shock radius. After the CCDS impact, a bulge is derived from the interface due to the shock-shock interaction inside the interface, and the number of bulges depends upon the number of cylinders. As the number of cylinders increases, the bulge becomes less pronounced, which is ascribed to additional shock-shock interactions inside the volume. As the distance between the cylinder and interface increases, an air cavity is first observed before the formation of a bulge. The amplitude of perturbation on the interface is found to reduce before the central reflected shock arrival because of the Rayleigh-Taylor stabilization effect. Through equating the pre-interface disturbance of the CCDS to the pre-shock perturbation of the perturbed interface, the initially linear growth rate is theoretically computed based on the impulsive model considering the Bell-Plesset effect. The theoretical results are found to deviate greatly from the experimental counterparts. Instead, taking the post-shock interface amplitude as an initial interface amplitude, the model works well. Therefore, the interface perturbations produced are notably smaller than the disturbances causing them. Moreover, the nonlinear behavior of perturbation growth is estimated by the model considering the Rayleigh-Taylor effect.

  20. Reflection High Energy Electron Diffraction Studies of Interface Formation.

    Science.gov (United States)

    Pukite, Paul

    1988-12-01

    The epitaxial growth of semiconductors, such as GaAs, by the technique of molecular beam epitaxy (MBE) has led to many improvements in device performance and capabilities. One important system is the epitaxial growth of GaAs on Si. This holds great promise for integrating optical and electronic devices on the same chip. The key to achieving this is to grow high quality GaAs layers on Si substrates. In this investigation, single-crystal GaAs was grown on Si and Ge substrates by MBE. The growth of the epitaxial layers was investigated in situ with reflection high-energy electron diffraction (RHEED). Important in this heteroepitaxial system is that two possible GaAs crystal orientations can be obtained. By using a theory of kinematic electron diffraction developed in the course of this work, the mechanisms and growth conditions which choose between the two GaAs orientations have been determined for the first time. A further result is that the epitaxial growth processes are anisotropic on the two orientations. This leads to different crystalline qualities dependent on the orientation. To understand this in more detail, the crystal growth process was formulated mathematically. By incorporating the concepts of anisotropic diffusion and adsorption into a nonlinear differential equation, the time-dependent growth and RHEED behavior has been calculated and compared to experiment. The experimental observations of RHEED intensity oscillations and two-dimensional clustering are in excellent agreement with the diffraction and growth theories. It is concluded that surface steps play a vital role in the crystal growth and interface formation processes reported in this study.

  1. Diffraction contrast imaging using virtual apertures

    Energy Technology Data Exchange (ETDEWEB)

    Gammer, Christoph, E-mail: cgammer@lbl.gov [National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory (United States); Department of Materials Science and Engineering, University of California, Berkeley (United States); Physics of Nanostructured Materials, Faculty of Physics, University of Vienna (Austria); Burak Ozdol, V. [National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory (United States); Liebscher, Christian H.; Minor, Andrew M. [National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory (United States); Department of Materials Science and Engineering, University of California, Berkeley (United States)

    2015-08-15

    Two methods on how to obtain the full diffraction information from a sample region and the associated reconstruction of images or diffraction patterns using virtual apertures are demonstrated. In a STEM-based approach, diffraction patterns are recorded for each beam position using a small probe convergence angle. Similarly, a tilt series of TEM dark-field images is acquired. The resulting datasets allow the reconstruction of either electron diffraction patterns, or bright-, dark- or annular dark-field images using virtual apertures. The experimental procedures of both methods are presented in the paper and are applied to a precipitation strengthened and creep deformed ferritic alloy with a complex microstructure. The reconstructed virtual images are compared with conventional TEM images. The major advantage is that arbitrarily shaped virtual apertures generated with image processing software can be designed without facing any physical limitations. In addition, any virtual detector that is specifically designed according to the underlying crystal structure can be created to optimize image contrast. - Highlights: • A dataset containing all structural information of a given position is recorded. • The dataset allows reconstruction of virtual diffraction patterns or images. • Specific virtual apertures are designed to image precipitates in a complex alloy. • Virtual diffraction patterns from arbitrarily small regions can be established. • Using STEM diffraction to record the dataset is more efficient than TEM dark-field.

  2. Nonlinear cochlear mechanics.

    Science.gov (United States)

    Zweig, George

    2016-05-01

    An earlier paper characterizing the linear mechanical response of the organ of Corti [J. Acoust. Soc. Am. 138, 1102-1121 (2015)] is extended to the nonlinear domain. Assuming the existence of nonlinear oscillators nonlocally coupled through the pressure they help create, the oscillator equations are derived and examined when the stimuli are modulated tones and clicks. The nonlinearities are constrained by the requirements of oscillator stability and the invariance of zero crossings in the click response to changes in click amplitude. The nonlinear oscillator equations for tones are solved in terms of the fluid pressure that drives them, and its time derivative, presumably a proxy for forces created by outer hair cells. The pressure equation is reduced to quadrature, the integrand depending on the oscillators' responses. The resulting nonlocally coupled nonlinear equations for the pressure, and oscillator amplitudes and phases, are solved numerically in terms of the fluid pressure at the stapes. Methods for determining the nonlinear damping directly from measurements are described. Once the oscillators have been characterized from their tone and click responses, the mechanical response of the cochlea to natural sounds may be computed numerically. Signal processing inspired by cochlear mechanics opens up a new area of nonlocal nonlinear time-frequency analysis.

  3. Propagation of Quasi-plane Nonlinear Waves in Tubes

    Directory of Open Access Journals (Sweden)

    P. Koníček

    2002-01-01

    Full Text Available This paper deals with possibilities of using the generalized Burgers equation and the KZK equation to describe nonlinear waves in circular ducts. A new method for calculating of diffraction effects taking into account boundary layer effects is described. The results of numerical solutions of the model equations are compared. Finally, the limits of validity of the used model equations are discussed with respect to boundary conditions and the radius of the circular duct. The limits of applicability of the KZK equation and the GBE equation for describing nonlinear waves in tubes are discussed.

  4. Two-dimensional x-ray diffraction

    CERN Document Server

    He, Bob B

    2009-01-01

    Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

  5. New diffractive results from the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Gallinaro, Michele; /Rockefeller U.

    2005-05-01

    Experimental results in diffractive processes are summarized and a few notable characteristics described in terms of Quantum Chromodynamics. Exclusive dijet production is used to establish a benchmark for future experiments in the quest for diffractive Higgs production at the Large Hadron Collider. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Stringent upper limits on the exclusive dijet production cross section are presented. The quark/gluon composition of dijet final states is used to provide additional hints on exclusive dijet production.

  6. Diffraction and diffusion in room acoustics

    DEFF Research Database (Denmark)

    Rindel, Jens Holger; Rasmussen, Birgit

    1996-01-01

    Diffraction and diffusion are two phenomena that are both related to the wave nature of sound. Diffraction due to the finite size of reflecting surfaces and the design of single reflectors and reflector arrays are discussed. Diffusion is the result of scattering of sound reflected from surfaces...... that are not plane but curved or irregular. The importance of diffusion has been demonstrated in concert halls. Methods for the design of diffusing surfaces and the development of new types of diffusers are reviewed. Finally, the importance of diffraction and diffusion in room acoustic computer models is discussed....

  7. Diffractive triangulation of radiative point sources

    CERN Document Server

    Vespucci, Stefano; Maneuski, Dzmitry; O'Shea, Val; Winkelmann, Aimo

    2016-01-01

    We describe a general method to determine the location of a point source of waves relative to a two-dimensional active pixel detector. Based on the inherent structural sensitivity of crystalline sensor materials, characteristic detector diffraction patterns can be used to triangulate the location of a wave emitter. As a practical application of the wide-ranging principle, a digital hybrid pixel detector is used to localize a source of electrons for Kikuchi diffraction pattern measurements in the scanning electron microscope. This provides a method to calibrate Kikuchi diffraction patterns for accurate measurements of microstructural crystal orientations, strains, and phase distributions.

  8. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind P

    2001-01-01

    The Optical Society of America (OSA) and SPIE - The International Society for Optical Engineering have awarded Govind Agrawal with an honorable mention for the Joseph W. Goodman Book Writing Award for his work on Nonlinear Fiber Optics, 3rd edition.Nonlinear Fiber Optics, 3rd Edition, provides a comprehensive and up-to-date account of the nonlinear phenomena occurring inside optical fibers. It retains most of the material that appeared in the first edition, with the exception of Chapter 6, which is now devoted to the polarization effects relevant for light propagation in optical

  9. Will Nonlinear Backcalculation Help?

    DEFF Research Database (Denmark)

    Ullidtz, Per

    2000-01-01

    demonstrates, that treating the subgrade as a nonlinear elastic material, can result in more realistic moduli and a much better agreement between measured and calculated stresses and strains.The response of nonlinear elastic materials can be calculated using the Finite Element Method (FEM). A much simpler...... approach is to use the Method of Equivalent Thicknesses (MET), modified for a nonlinear subgrade. The paper includes an example where moduli backcalculated using FEM, linear elastic theory and MET are compared. Stresses and strains predicted by the three methods are also compared to measured values...

  10. Nonlinear graphene metamaterial

    CERN Document Server

    Nikolaenko, Andrey E; Atmatzakis, Evangelos; Luo, Zhiqiang; Shen, Ze Xiang; De Angelis, Francesco; Boden, Stuart A; Di Fabrizio, Enzo; Zheludev, Nikolay I

    2012-01-01

    We demonstrate that the broadband nonlinear optical response of graphene can be resonantly enhanced by more than an order of magnitude through hybridization with a plasmonic metamaterial,while retaining an ultrafast nonlinear response time of ~1 ps. Transmission modulation close to ~1% is seen at a pump uence of ~0.03 mJ/cm^2 at the wavelength of ~1600 nm. This approach allows to engineer and enhance graphene's nonlinearity within a broad wavelength range enabling applications in optical switching, mode-locking and pulse shaping.

  11. Tunable Beam Diffraction in Infiltrated Microstructured Fibers

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis H.; Neshev, Dragomir N.;

    We experimentally study beam propagation in two dimensional photonic lattices in microstructured optical fibers infiltrated with high index liquids. We demonstrate strongly tunable beam diffraction by dynamically varying the coupling between individual lattice sites....

  12. Thermal diffractive corrections to Casimir energies

    CERN Document Server

    Kabat, Daniel

    2011-01-01

    We study the interplay of thermal and diffractive effects in Casimir energies. We consider plates with edges, oriented either parallel or perpendicular to each other, as well as a single plate with a slit. We compute the Casimir energy at finite temperature using a formalism in which the diffractive effects are encoded in a lower dimensional non-local field theory that lives in the gap between the plates. The formalism allows for a clean separation between direct or geometric effects and diffractive effects, and makes an analytic derivation of the temperature dependence of the free energy possible. At low temperatures, with Dirichlet boundary conditions on the plates, we find that diffractive effects make a correction to the free energy which scales as T^6 for perpendicular plates, as T^4 for slits, and as T^4 log T for parallel plates.

  13. The logarithmic slope in diffractive DIS

    CERN Document Server

    Gay-Ducati, M B; Machado, M V T

    2002-01-01

    The logarithmic slope of diffractive structure function is a potential observable to separate the hard and soft contributions in diffraction, allowing to disentangle the QCD dynamics at small-x region. In this paper we extend our previous analyzes and calculate the diffractive logarithmic slope for three current approaches in the literature: (i) the Bartels-Wusthoff model, based on perturbative QCD, (ii) the CKMT model, based on Regge theory and (iii) the Golec-Biernat-Wusthoff model which assumes that the saturation phenomena is present in the HERA kinematic region. We analyze the transition region of small to large momentum transfer and verify that future experimental results on the diffractive logarithmic slope could discriminate between these approaches.

  14. Atomic resolution 3D electron diffraction microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Jianwei; Ohsuna, Tetsu; Terasaki, Osamu; O' Keefe, Michael A.

    2002-03-01

    Electron lens aberration is the major barrier limiting the resolution of electron microscopy. Here we describe a novel form of electron microscopy to overcome electron lens aberration. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a 2 x 2 x 2 unit cell nano-crystal (framework of LTA [Al12Si12O48]8) can be ab initio determined at the resolution of 1 Angstrom from a series of simulated noisy diffraction pattern projections with rotation angles ranging from -70 degrees to +70 degrees in 5 degrees increments along a single rotation axis. This form of microscopy (which we call 3D electron diffraction microscopy) does not require any reference waves, and can image the 3D structure of nanocrystals, as well as non-crystalline biological and materials science samples, with the resolution limited only by the quality of sample diffraction.

  15. Diffractive waveplates for long wave infrared

    Science.gov (United States)

    Ouskova, Elena; Roberts, David; Tabiryan, Nelson; Steeves, D. M.; Kimball, B. R.

    2017-05-01

    We report about developing long-wave infrared diffractive optical components based on liquid crystals. The components show high efficiency and high transparency for the 10.6 μm wavelength of CO2 laser beam.

  16. Kinematic Diffraction from a Mathematical Viewpoint

    CERN Document Server

    Baake, Michael

    2011-01-01

    Mathematical diffraction theory is concerned with the analysis of the diffraction image of a given structure and the corresponding inverse problem of structure determination. In recent years, the understanding of systems with continuous and mixed spectra has improved considerably. Simultaneously, their relevance has grown in practice as well. In this context, the phenomenon of homometry shows various unexpected new facets. This is particularly so for systems with stochastic components. After the introduction to the mathematical tools, we briefly discuss pure point spectra, based on the Poisson summation formula for lattice Dirac combs. This provides an elegant approach to the diffraction formulas of infinite crystals and quasicrystals. We continue by considering classic deterministic examples with singular or absolutely continuous diffraction spectra. In particular, we recall an isospectral family of structures with continuously varying entropy. We close with a summary of more recent results on the diffractio...

  17. X-ray diffraction: instrumentation and applications.

    Science.gov (United States)

    Bunaciu, Andrei A; Udriştioiu, Elena Gabriela; Aboul-Enein, Hassan Y

    2015-01-01

    X-ray diffraction (XRD) is a powerful nondestructive technique for characterizing crystalline materials. It provides information on structures, phases, preferred crystal orientations (texture), and other structural parameters, such as average grain size, crystallinity, strain, and crystal defects. X-ray diffraction peaks are produced by constructive interference of a monochromatic beam of X-rays scattered at specific angles from each set of lattice planes in a sample. The peak intensities are determined by the distribution of atoms within the lattice. Consequently, the X-ray diffraction pattern is the fingerprint of periodic atomic arrangements in a given material. This review summarizes the scientific trends associated with the rapid development of the technique of X-ray diffraction over the past five years pertaining to the fields of pharmaceuticals, forensic science, geological applications, microelectronics, and glass manufacturing, as well as in corrosion analysis.

  18. Diffractive Optical Elements for Dynamic Optical Coupling

    Institute of Scientific and Technical Information of China (English)

    Changhe Zhou; Xin Zhao; Liren Liu

    2003-01-01

    Diffractive optical elements such as the complementary Dammann gratings are incorporated for dynamic optical fiber splitting and combining. Experimental results of 1′8 dynamic optical couplings are presented.

  19. Diffractive Optical Elements for Dynamic Optical Coupling

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Diffractive optical elements such as the complementary Dammann gratings are incorporated for dynamic optical fiber splitting and combining. Experimental results of 1×8 dynamic optical couplings are presented.

  20. Diffraction analysis of the microstructure of materials

    CERN Document Server

    Scardi, Paolo

    2004-01-01

    Diffraction Analysis of the Microstructure of Materials provides an overview of diffraction methods applied to the analysis of the microstructure of materials. Since crystallite size and the presence of lattice defects have a decisive influence on the properties of many engineering materials, information about this microstructure is of vital importance in developing and assessing materials for practical applications. The most powerful and usually non-destructive evaluation techniques available are X-ray and neutron diffraction. The book details, among other things, diffraction-line broadening methods for determining crystallite size and atomic-scale strain due, e.g. to dislocations, and methods for the analysis of residual (macroscale) stress. The book assumes only a basic knowledge of solid-state physics and supplies readers sufficient information to apply the methods themselves.

  1. Multipolar nonlinear nanophotonics

    CERN Document Server

    Smirnova, Daria

    2016-01-01

    Nonlinear nanophotonics is a rapidly developing field with many useful applications for a design of nonlinear nanoantennas, light sources, nanolasers, sensors, and ultrafast miniature metadevices. A tight confinement of the local electromagnetic fields in resonant photonic nanostructures can boost nonlinear optical effects, thus offering versatile opportunities for subwavelength control of light. To achieve the desired functionalities, it is essential to gain flexible control over the near- and far-field properties of nanostructures. Thus, both modal and multipolar analyses are widely exploited for engineering nonlinear scattering from resonant nanoscale elements, in particular for enhancing the near-field interaction, tailoring the far-field multipolar interference, and optimization of the radiation directionality. Here, we review the recent advances in this recently emerged research field ranging from metallic structures exhibiting localized plasmonic resonances to hybrid metal-dielectric and all-dielectric...

  2. Solitons in nonlinear lattices

    CERN Document Server

    Kartashov, Yaroslav V; Torner, Lluis

    2010-01-01

    This article offers a comprehensive survey of results obtained for solitons and complex nonlinear wave patterns supported by purely nonlinear lattices (NLs), which represent a spatially periodic modulation of the local strength and sign of the nonlinearity, and their combinations with linear lattices. A majority of the results obtained, thus far, in this field and reviewed in this article are theoretical. Nevertheless, relevant experimental settings are surveyed too, with emphasis on perspectives for implementation of the theoretical predictions in the experiment. Physical systems discussed in the review belong to the realms of nonlinear optics (including artificial optical media, such as photonic crystals, and plasmonics) and Bose-Einstein condensation (BEC). The solitons are considered in one, two, and three dimensions (1D, 2D, and 3D). Basic properties of the solitons presented in the review are their existence, stability, and mobility. Although the field is still far from completion, general conclusions c...

  3. Nonlinear plasmonic antennas

    Directory of Open Access Journals (Sweden)

    Shakeeb Bin Hasan

    2014-12-01

    Full Text Available Contrary to traditional optical elements, plasmonic antennas made from nanostructured metals permit the localization of electromagnetic fields on length scales much smaller than the wavelength of light. This results in huge amplitudes for the electromagnetic field close to the antenna being conducive for the observation of nonlinear effects already at moderate pump powers. Thus, these antennas exhibit a promising potential to achieve optical frequency conversion and all-optical control of light at the nano-scale. This opens unprecedented opportunities for ultrafast nonlinear spectroscopy, sensing devices, on-chip optical frequency conversion, nonlinear optical metamaterials, and novel photon sources. Here, we review some of the recent advances in exploiting the potential of plasmonic antennas to realize robust nonlinear applications.

  4. Ultrafast nonlinear optics

    CERN Document Server

    Leburn, Christopher; Reid, Derryck

    2013-01-01

    The field of ultrafast nonlinear optics is broad and multidisciplinary, and encompasses areas concerned with both the generation and measurement of ultrashort pulses of light, as well as those concerned with the applications of such pulses. Ultrashort pulses are extreme events – both in terms of their durations, and also the high peak powers which their short durations can facilitate. These extreme properties make them powerful experiment tools. On one hand, their ultrashort durations facilitate the probing and manipulation of matter on incredibly short timescales. On the other, their ultrashort durations can facilitate high peak powers which can drive highly nonlinear light-matter interaction processes. Ultrafast Nonlinear Optics covers a complete range of topics, both applied and fundamental in nature, within the area of ultrafast nonlinear optics. Chapters 1 to 4 are concerned with the generation and measurement of ultrashort pulses. Chapters 5 to 7 are concerned with fundamental applications of ultrasho...

  5. Nonlinear Source Emulator

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem

    and remains the prime source of energy in non-terrestrial applications such as those in sky-explorers. However, a renewable energy source is expensive, bulky, and its performance is weather dependent, which make testing of downstream converters very difficult. As a result, a nonlinear source emulator (NSE......) is a good solution to solve the problems associated with the use of real nonlinear sources in testing phases. However, a recent technical survey conducted during this work shows that most existing NSEs have only been concerned with simulating nonlinear systems in terrestrial applications. Furthermore......, their dynamic performance were not fast enough in order to imitate how a real nonlinear energy source would react under extreme conditions and operation modes. Particularly, a system in the sky can experience a step change of sunlight irradiation. Moreover, operation modes may include load step between nominal...

  6. Introduction to nonlinear science

    CERN Document Server

    Nicolis, G

    1995-01-01

    One of the most unexpected results in science in recent years is that quite ordinary systems obeying simple laws can give rise to complex, nonlinear or chaotic, behavior. In this book, the author presents a unified treatment of the concepts and tools needed to analyze nonlinear phenomena and to outline some representative applications drawn from the physical, engineering, and biological sciences. Some of the interesting topics covered include: dynamical systems with a finite number of degrees of freedom, linear stability analysis of fixed points, nonlinear behavior of fixed points, bifurcation analysis, spatially distributed systems, broken symmetries, pattern formation, and chaotic dynamics. The author makes a special effort to provide a logical connection between ordinary dynamical systems and spatially extended systems, and to balance the emphasis on chaotic behavior and more classical nonlinear behavior. He also develops a statistical approach to complex systems and compares it to traditional deterministi...

  7. Nonlinear magnetoinductive transmission lines

    CERN Document Server

    Lazarides, Nikos; Tsironis, G P

    2011-01-01

    Power transmission in one-dimensional nonlinear magnetic metamaterials driven at one end is investigated numerically and analytically in a wide frequency range. The nonlinear magnetic metamaterials are composed of varactor-loaded split-ring resonators which are coupled magnetically through their mutual inductances, forming thus a magnetoiductive transmission line. In the linear limit, significant power transmission along the array only appears for frequencies inside the linear magnetoinductive wave band. We present analytical, closed form solutions for the magnetoinductive waves transmitting the power in this regime, and their discrete frequency dispersion. When nonlinearity is important, more frequency bands with significant power transmission along the array may appear. In the equivalent circuit picture, the nonlinear magnetoiductive transmission line driven at one end by a relatively weak electromotive force, can be modeled by coupled resistive-inductive-capacitive (RLC) circuits with voltage-dependent cap...

  8. Optimization under Nonlinear Constraints

    OpenAIRE

    1982-01-01

    In this paper a timesaving method is proposed for maximizing likelihood functions when the parameter space is subject to nonlinear constraints, expressible as second order polynomials. The suggested approach is especially attractive when dealing with systems with many parameters.

  9. Nonlinearity in nanomechanical cantilevers

    DEFF Research Database (Denmark)

    Villanueva Torrijo, Luis Guillermo; Karabalin, R. B.; Matheny, M. H.

    2013-01-01

    Euler-Bernoulli beam theory is widely used to successfully predict the linear dynamics of micro-and nanocantilever beams. However, its capacity to characterize the nonlinear dynamics of these devices has not yet been rigorously assessed, despite its use in nanoelectromechanical systems development....... These findings underscore the delicate balance between inertial and geometric nonlinear effects in the fundamental mode, and strongly motivate further work to develop theories beyond the Euler-Bernoulli approximation. DOI: 10.1103/PhysRevB.87.024304....... In this article, we report the first highly controlled measurements of the nonlinear response of nanomechanical cantilevers using an ultralinear detection system. This is performed for an extensive range of devices to probe the validity of Euler-Bernoulli theory in the nonlinear regime. We find that its...

  10. Nonlinear Stokes Mueller Polarimetry

    CERN Document Server

    Samim, Masood; Barzda, Virginijus

    2015-01-01

    The Stokes Mueller polarimetry is generalized to include nonlinear optical processes such as second- and third-harmonic generation, sum- and difference-frequency generations. The overall algebraic form of the polarimetry is preserved, where the incoming and outgoing radiations are represented by column vectors and the intervening medium is represented by a matrix. Expressions for the generalized nonlinear Stokes vector and the Mueller matrix are provided in terms of coherency and correlation matrices, expanded by higher-dimensional analogues of Pauli matrices. In all cases, the outgoing radiation is represented by the conventional $4\\times 1$ Stokes vector, while dimensions of the incoming radiation Stokes vector and Mueller matrix depend on the order of the process being examined. In addition, relation between nonlinear susceptibilities and the measured Mueller matrices are explicitly provided. Finally, the approach of combining linear and nonlinear optical elements is discussed within the context of polarim...

  11. Simulating interference and diffraction in instructional laboratories

    Science.gov (United States)

    Maurer, L.

    2013-03-01

    Studieshave shown that standard lectures and instructional laboratory experiments are not effective at teaching interference and diffraction. In response, the author created an interactive computer program that simulates interference and diffraction effects using the finite difference time domain method. The software allows students to easily control, visualize and quantitatively measure the effects. Students collected data from simulations as part of their laboratory exercise, and they performed well on a subsequent quiz, showing promise for this approach.

  12. A Spectrometer Based on Diffractive Lens

    Institute of Scientific and Technical Information of China (English)

    WANG Daoyi; YAN Yingbai; JIN Guofan; WU Minxian

    2001-01-01

    A novel spectrometer is designed based on diffractive lens. It is essentially a flat field spectrometer. All the focal points are along the optical axis. Besides, all the asymmetrical aberrations vanish in our mounting. Thus low aberration can be obtained. In this article a diffractive lens is modeled as a special grating and analyzed by using a grating-based method. And a stigmatic point is introduced to reduce the aberrations.

  13. [X-ray diffraction spectrum of heroin].

    Science.gov (United States)

    Hu, X; Kan, J; Yuan, B

    1999-06-01

    In this paper, practical measured X-ray diffraction spectra of heroin and opium are given and the parameters of each diffraction peak of the heroin are listed. The heroin belongs to orthorhombic crystal system; the basic vectors of the primitive cell are: a = 8.003, b = 14.373, c = 16.092 x 10(-10) m. As compared with the standard spectra of pure heroin and sucrose, the main doped additive checked by us, is sugar affirmatively.

  14. Diffractive Leptoproduction of Vector Mesons in QCD

    OpenAIRE

    Brodsky, Stanley J.; Frankfurt, L.; Gunion, J. F.; Mueller, A.H.; Strikman, M.

    1994-01-01

    We demonstrate that the distinctive features of the forward differential cross section of diffractive leptoproduction of a vector meson can be legitimately calculated in perturbative QCD in terms of the light-cone $q \\bar q$ wave function of the vector meson and the gluon distribution of the target. In particular, we calculate the $Q^2$ and nuclear dependence of the diffractive leptoproduction of vector mesons and estimate the cross section. The production of longitudinally polarized vector m...

  15. Unified QCD picture of hard diffraction

    CERN Document Server

    Navelet, H

    2001-01-01

    Using a combination of S-Matrix and perturbative QCD properties in the small x_{Bjorken} regime, we propose a formulation of hard diffraction unifying the partonic (Ingelman-Schlein) Pomeron, Soft Colour Interaction and QCD dipole descriptions. In particular, we show that all three approaches give an unique and mutually compatible formula for the proton diffractive structure functions incorporating perturbative and non perturbative QCD features.

  16. Diffractive and ultraperipheral physics with ALICE

    CERN Document Server

    Schicker, Rainer

    2008-01-01

    The ALICE experiment consists of a central barrel, a muon spe ctrometer, zero degree calorimeters and additional detectors for trigger and event classificati on purposes. Such a geometry allows the implementation of a double gap trigger. A diffractive physi cs program of ALICE is outlined and a few specific reaction channels are discussed in order to ill ustrate the interest in such a diffractive physics program

  17. Adaptive and Nonlinear Control

    Science.gov (United States)

    1992-02-29

    in [22], we also applied the concept of zero dynamics to the problem of exact linearization of a nonlinear control system by dynamic feedback. Exact ...nonlinear systems, although it was well-known that the conditions for exact linearization are very stringent and consequently do not apply to a broad...29th IEEE Conference n Decision and Control, Invited Paper delivered by Dr. Gilliam. Exact Linearization of Zero Dynamics, 29th IEEE Conference on

  18. Nonlinear Optics and Turbulence

    Science.gov (United States)

    1992-10-01

    currently at Queen Mary College, London Patrick Dunne, (Ph.D., 1987, M.I.T., Hydrodynamic Stability, Nonlinear Waves), 1987-1988. Alecsander Dyachenko...U I I I U I I 3 9 3 V. BIOGRAPHIES A. FACULTY BRUCE BAYLY, 31, Ph.D. 1986, Princeton University. Postdoctoral visiting member 1986-88 at Courant...Caputo, A. C. Newell, and M. Shelley , "Nonlinear Wave Propagation Through a Random Medium and Soliton Tunneling", Integrable Systems and

  19. When fast atom diffraction turns 3D

    Energy Technology Data Exchange (ETDEWEB)

    Zugarramurdi, Asier; Borisov, Andrei G., E-mail: andrei.borissov@u-psud.fr

    2013-12-15

    Fast atom diffraction at surfaces (FAD) in grazing incidence geometry is characterized by the slow motion in the direction perpendicular to the surface and fast motion parallel to the surface plane along a low index direction. It is established experimentally that for the typical surfaces the FAD reveals the 2D diffraction patterns associated with exchange of the reciprocal lattice vector perpendicular to the direction of fast motion. The reciprocal lattice vector exchange along the direction of fast motion is negligible. The usual approximation made in the description of the experimental data is then to assume that the effective potential leading to the diffraction results from the averaging of the 3D surface potential along the atomic strings forming the axial channel. In this work we use full quantum wave packet propagation calculations to study theoretically the possibility to observe the 3D diffraction in FAD experiments. We show that for the surfaces with large unit cell, such as can be the case for reconstructed or vicinal surfaces, the 3D diffraction can be observed. The reciprocal lattice vector exchange along the direction of fast motion leads to several Laue circles in the diffraction pattern.

  20. Robust Nonlinear Neural Codes

    Science.gov (United States)

    Yang, Qianli; Pitkow, Xaq

    2015-03-01

    Most interesting natural sensory stimuli are encoded in the brain in a form that can only be decoded nonlinearly. But despite being a core function of the brain, nonlinear population codes are rarely studied and poorly understood. Interestingly, the few existing models of nonlinear codes are inconsistent with known architectural features of the brain. In particular, these codes have information content that scales with the size of the cortical population, even if that violates the data processing inequality by exceeding the amount of information entering the sensory system. Here we provide a valid theory of nonlinear population codes by generalizing recent work on information-limiting correlations in linear population codes. Although these generalized, nonlinear information-limiting correlations bound the performance of any decoder, they also make decoding more robust to suboptimal computation, allowing many suboptimal decoders to achieve nearly the same efficiency as an optimal decoder. Although these correlations are extremely difficult to measure directly, particularly for nonlinear codes, we provide a simple, practical test by which one can use choice-related activity in small populations of neurons to determine whether decoding is suboptimal or optimal and limited by correlated noise. We conclude by describing an example computation in the vestibular system where this theory applies. QY and XP was supported by a grant from the McNair foundation.

  1. Nonlinear Multiantenna Detection Methods

    Directory of Open Access Journals (Sweden)

    Chen Sheng

    2004-01-01

    Full Text Available A nonlinear detection technique designed for multiple-antenna assisted receivers employed in space-division multiple-access systems is investigated. We derive the optimal solution of the nonlinear spatial-processing assisted receiver for binary phase shift keying signalling, which we refer to as the Bayesian detector. It is shown that this optimal Bayesian receiver significantly outperforms the standard linear beamforming assisted receiver in terms of a reduced bit error rate, at the expense of an increased complexity, while the achievable system capacity is substantially enhanced with the advent of employing nonlinear detection. Specifically, when the spatial separation expressed in terms of the angle of arrival between the desired and interfering signals is below a certain threshold, a linear beamformer would fail to separate them, while a nonlinear detection assisted receiver is still capable of performing adequately. The adaptive implementation of the optimal Bayesian detector can be realized using a radial basis function network. Two techniques are presented for constructing block-data-based adaptive nonlinear multiple-antenna assisted receivers. One of them is based on the relevance vector machine invoked for classification, while the other on the orthogonal forward selection procedure combined with the Fisher ratio class-separability measure. A recursive sample-by-sample adaptation procedure is also proposed for training nonlinear detectors based on an amalgam of enhanced -means clustering techniques and the recursive least squares algorithm.

  2. Nonlinear systems in medicine.

    Science.gov (United States)

    Higgins, John P

    2002-01-01

    Many achievements in medicine have come from applying linear theory to problems. Most current methods of data analysis use linear models, which are based on proportionality between two variables and/or relationships described by linear differential equations. However, nonlinear behavior commonly occurs within human systems due to their complex dynamic nature; this cannot be described adequately by linear models. Nonlinear thinking has grown among physiologists and physicians over the past century, and non-linear system theories are beginning to be applied to assist in interpreting, explaining, and predicting biological phenomena. Chaos theory describes elements manifesting behavior that is extremely sensitive to initial conditions, does not repeat itself and yet is deterministic. Complexity theory goes one step beyond chaos and is attempting to explain complex behavior that emerges within dynamic nonlinear systems. Nonlinear modeling still has not been able to explain all of the complexity present in human systems, and further models still need to be refined and developed. However, nonlinear modeling is helping to explain some system behaviors that linear systems cannot and thus will augment our understanding of the nature of complex dynamic systems within the human body in health and in disease states.

  3. Handbook of nonlinear optical crystals

    CERN Document Server

    Dmitriev, Valentin G; Nikogosyan, David N

    1991-01-01

    This Handbook of Nonlinear Optical Crystals provides a complete description of the properties and applications of nonlinear crystals In addition, it presents the most important equations for calculating the main parameters of nonlinear frequency converters This comprehensive reference work will be of great value to all scientists and engineers working in nonlinear optics, quantum electronics and laser physics

  4. Effect of thickness on nonlinear absorption properties of graphite oxide thin films

    Science.gov (United States)

    Sreeja, V. G.; Cheruvalathu, Ajina; Reshmi, R.; Anila, E. I.; Thomas, Sheenu; Jayaraj, M. K.

    2016-10-01

    We report the thickness dependent structural, linear and nonlinear optical properties of graphite oxide (GO) thin films synthesized by spin coating method. We observed that the structural, linear and nonlinear optical properties can be tuned by the film thickness in GO. The nonlinear absorption studies by open aperture z scan technique exhibited a saturable absorption. The nonlinear absorption coefficient and saturation intensity varies with film thickness which is attributed to increased localized defect states in the energy band gap. Our results emphasize relatively large thickness dependent optical nonlinearity of GO thin films and its potential for optical pulse generation, exploring the way to GO based nonlinear applications in Q switched mode locking laser systems. All the coated GO films were characterized by X-Ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis absorption spectroscopy (UV-Vis), Photoluminescence (PL) and Scanning electron microscope (SEM) measurements.

  5. Oscillons, solitons, and domain walls in arrays of nonlinear plasmonic nanoparticles.

    Science.gov (United States)

    Noskov, Roman; Belov, Pavel; Kivshar, Yuri

    2012-01-01

    The study of metal nanoparticles plays a central role in the emerging novel technologies employing optics beyond the diffraction limit. Combining strong surface plasmon resonances, high intrinsic nonlinearities and deeply subwavelength scales, arrays of metal nanoparticles offer a unique playground to develop novel concepts for light manipulation at the nanoscale. Here we suggest a novel principle to control localized optical energy in chains of nonlinear subwavelength metal nanoparticles based on the fundamental nonlinear phenomenon of modulation instability. In particular, we demonstrate that modulation instability can lead to the formation of long-lived standing and moving nonlinear localized modes of several distinct types such as bright and dark solitons, oscillons, and domain walls. We analyze the properties of these nonlinear localized modes and reveal different scenarios of their dynamics including transformation of one type of mode to another. We believe this work paves a way towards the development of nonlinear nanophotonics circuitry.

  6. Nonlinear Approaches in Engineering Applications

    CERN Document Server

    Jazar, Reza

    2012-01-01

    Nonlinear Approaches in Engineering Applications focuses on nonlinear phenomena that are common in the engineering field. The nonlinear approaches described in this book provide a sound theoretical base and practical tools to design and analyze engineering systems with high efficiency and accuracy and with less energy and downtime. Presented here are nonlinear approaches in areas such as dynamic systems, optimal control and approaches in nonlinear dynamics and acoustics. Coverage encompasses a wide range of applications and fields including mathematical modeling and nonlinear behavior as applied to microresonators, nanotechnologies, nonlinear behavior in soil erosion,nonlinear population dynamics, and optimization in reducing vibration and noise as well as vibration in triple-walled carbon nanotubes. This book also: Provides a complete introduction to nonlinear behavior of systems and the advantages of nonlinearity as a tool for solving engineering problems Includes applications and examples drawn from the el...

  7. Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media

    CERN Document Server

    Lai, Puxiang; Tay, Jian Wei; Wang, Lihong V

    2014-01-01

    Non-invasively focusing light into strongly scattering media, such as biological tissue, is highly desirable but challenging. Recently, wavefront shaping technologies guided by ultrasonic encoding or photoacoustic sensing have been developed to address this limitation. So far, these methods provide only acoustic diffraction-limited optical focusing. Here, we introduce nonlinear photoacoustic wavefront shaping (PAWS), which achieves optical diffraction-limited (i.e. single-speckle-grain) focusing in scattering media. We develop an efficient dual-pulse excitation approach to generate strong nonlinear photoacoustic (PA) signals based on the Grueneisen memory effect. These nonlinear PA signals are used as feedback to guide iterative wavefront optimization. By maximizing the amplitude of the nonlinear PA signal, light is effectively focused to a single optical speckle grain. Experimental results demonstrate a clear optical focus on the scale of 5-7 micrometers, which is ~10 times smaller than the acoustic focus in...

  8. Simulations of nonlinear continuous wave pressure fields in FOCUS

    Science.gov (United States)

    Zhao, Xiaofeng; Hamilton, Mark F.; McGough, Robert J.

    2017-03-01

    The Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation is a parabolic approximation to the Westervelt equation that models the effects of diffraction, attenuation, and nonlinearity. Although the KZK equation is only valid in the far field of the paraxial region for mildly focused or unfocused transducers, the KZK equation is widely applied in medical ultrasound simulations. For a continuous wave input, the KZK equation is effectively modeled by the Bergen Code [J. Berntsen, Numerical Calculations of Finite Amplitude Sound Beams, in M. F. Hamilton and D. T. Blackstock, editors, Frontiers of Nonlinear Acoustics: Proceedings of 12th ISNA, Elsevier, 1990], which is a finite difference model that utilizes operator splitting. Similar C++ routines have been developed for FOCUS, the `Fast Object-Oriented C++ Ultrasound Simulator' (http://www.egr.msu.edu/˜fultras-web) to calculate nonlinear pressure fields generated by axisymmetric flat circular and spherically focused ultrasound transducers. This new routine complements an existing FOCUS program that models nonlinear ultrasound propagation with the angular spectrum approach [P. T. Christopher and K. J. Parker, J. Acoust. Soc. Am. 90, 488-499 (1991)]. Results obtained from these two nonlinear ultrasound simulation approaches are evaluated and compared for continuous wave linear simulations. The simulation results match closely in the farfield of the paraxial region, but the results differ in the nearfield. The nonlinear pressure field generated by a spherically focused transducer with a peak surface pressure of 0.2MPa radiating in a lossy medium with β = 3.5 is simulated, and the computation times are also evaluated. The nonlinear simulation results demonstrate acceptable agreement in the focal zone. These two related nonlinear simulation approaches are now included with FOCUS to enable convenient simulations of nonlinear pressure fields on desktop and laptop computers.

  9. Blazed Grating Resonance Conditions and Diffraction Efficiency Optical Transfer Function

    KAUST Repository

    Stegenburgs, Edgars

    2017-01-08

    We introduce a general approach to study diffraction harmonics or resonances and resonance conditions for blazed reflecting gratings providing knowledge of fundamental diffraction pattern and qualitative understanding of predicting parameters for the most efficient diffraction.

  10. Oscillons, solitons, and domain walls in arrays of nonlinear plasmonic nanoparticles

    OpenAIRE

    Roman Noskov; Pavel Belov; Yuri Kivshar

    2012-01-01

    The study of metal nanoparticles plays a central role in the emerging novel technologies employing optics beyond the diffraction limit. Combining strong surface plasmon resonances, high intrinsic nonlinearities and deeply subwavelength scales, arrays of metal nanoparticles offer a unique playground to develop novel concepts for light manipulation at the nanoscale. Here we suggest a novel principle to control localized optical energy in chains of nonlinear subwavelength metal nanoparticles bas...

  11. Phenomenology of hard diffraction at high energies

    CERN Document Server

    Machado, Magno V T

    2016-01-01

    We present some of the topics covered in two lectures under the same title that was given at the "Summer School on High Energy Physics at the LHC: New trends in HEP" in Natal, Brazil. In this contribution we give a brief review on the application of perturbative QCD to the hard diffractive processes. Such reactions involving a hard scale can be understood in terms of quarks and gluons degrees of freedom and have become an useful tool for investigating the low-$x$ structure of the proton and the behavior of QCD in the high-density regime. We start using the information from the $ep$ collisions at HERA concerned to the inclusive diffraction to introduce the concept of diffractive parton distributions. Their interpretation in the resolved pomeron model is addressed and we discuss the limits of diffractive hard-scattering factorization for hadron-hadron collisions. Some examples of phenomenology for the diffractive production of $W/Z$, heavy $Q\\bar{Q}$ and quarkonium in hadron-hadron reactions are presented. We a...

  12. Surface diffusion studies by optical diffraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, X.D.

    1992-11-01

    The newly developed optical techniques have been combined with either second harmonic (SH) diffraction or linear diffraction off a monolayer adsorbate grating for surface diffusion measurement. Anisotropy of surface diffusion of CO on Ni(l10) was used as a demonstration for the second harmonic dim reaction method. The linear diffraction method, which possesses a much higher sensitivity than the SH diffraction method, was employed to study the effect of adsorbate-adsorbate interaction on CO diffusion on Ni(l10) surface. Results showed that only the short range direct CO-CO orbital overlapping interaction influences CO diffusion but not the long range dipole-dipole and CO-NI-CO interactions. Effects of impurities and defects on surface diffusion were further explored by using linear diffraction method on CO/Ni(110) system. It was found that a few percent S impurity can alter the CO diffusion barrier height to a much higher value through changing the Ni(110) surface. The point defects of Ni(l10) surface seem to speed up CO diffusion significantly. A mechanism with long jumps over multiple lattice distance initiated by CO filled vacancy is proposed to explain the observed defect effect.

  13. Nonlinear pulsation masses

    Energy Technology Data Exchange (ETDEWEB)

    Davis, C.G.

    1990-01-01

    The advent of nonlinear pulsation theory really coincides with the development of the large computers after the second world war. Christy and Stobbie were the first to make use of finite difference techniques on computers to model the bumps'' observed in the classical Cepheid light and velocity curves, the so-called Hertzsprung'' sequence. Following this work a more sophisticated analysis of the light and velocity curves from the models was made by Simon and Davis using Fourier techniques. Recently a simpler amplitude equation formalism has been developed that helps explain this resonance mechanism. The determination of Population I Cepheid masses by nonlinear methods will be discussed. For the lower mass objects, such as RR Lyrae and BL Her. stars, we find general agreement using evolutionary masses and nonlinear pulsation theory. An apparent difficulty of nonlinear pulsation theory occurs in the understanding of double'' mode pulsation, which will also be discussed. Recent studies in nonlinear pulsation theory have dealt with the question of mode selection, period doubling and the trends towards chaotic behavior such as is observed in the transition from W Virginis to RV Tauri-like stars. 10 refs., 1 fig., 2 tabs.

  14. Nonlinear super-resolution nano-optics and applications

    CERN Document Server

    Wei, Jingsong

    2015-01-01

    This book covers many advances in the subjects of nano-optics and nano photonics. The author describes the principle and technical schematics of common methods for breaking through the optical diffraction limit and focuses on realizing optical super-resolution with nonlinear effects of thin film materials. The applications of nonlinear optical super-resolution effects in nano-data storage, nanolithography, and nano-imaging are also presented. This book is useful to graduate students majoring in optics and nano science and also serves as a reference book for academic researchers, engineers, technical professionals in the fields of super-resolution optics and laser techniques, nano-optics and nano photonics, nano-data storage, nano imaging, micro/nanofabrication and nanolithography and nonlinear optics.

  15. Experimental Observation of Bohr's Nonlinear Fluidic Surface Oscillation

    CERN Document Server

    Moon, Songky; Kwak, Hojeong; Yang, Juhee; Lee, Sang-Bum; Kim, Soyun; An, Kyungwon

    2015-01-01

    Niels Bohr in the early stage of his career developed a nonlinear theory of fluidic surface oscillation in order to study surface tension of liquids. His theory includes the nonlinear interaction between multipolar surface oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It predicts a specific normalized magnitude of $0.41\\dot{6}\\eta^2$ for an octapolar component, nonlinearly induced by a quadrupolar one with a magnitude of $\\eta$ much less than unity. No experimental confirmation on this prediction has been reported. Nonetheless, accurate determination of multipolar components is important as in optical fiber spinning, film blowing and recently in optofluidic microcavities for ray and wave chaos studies and photonics applications. Here, we report experimental verification of his theory. By using optical forward diffraction, we measured the cross-sectional boundary profiles at extreme positions of a surface-oscillating liquid column ejected from a deformed microscopic orifice. We obtained...

  16. Nonlinear elastic waves in materials

    CERN Document Server

    Rushchitsky, Jeremiah J

    2014-01-01

    The main goal of the book is a coherent treatment of the theory of propagation in materials of nonlinearly elastic waves of displacements, which corresponds to one modern line of development of the nonlinear theory of elastic waves. The book is divided on five basic parts: the necessary information on waves and materials; the necessary information on nonlinear theory of elasticity and elastic materials; analysis of one-dimensional nonlinear elastic waves of displacement – longitudinal, vertically and horizontally polarized transverse plane nonlinear elastic waves of displacement; analysis of one-dimensional nonlinear elastic waves of displacement – cylindrical and torsional nonlinear elastic waves of displacement; analysis of two-dimensional nonlinear elastic waves of displacement – Rayleigh and Love nonlinear elastic surface waves. The book is addressed first of all to people working in solid mechanics – from the students at an advanced undergraduate and graduate level to the scientists, professional...

  17. Nonlinear Dynamic Force Spectroscopy

    CERN Document Server

    Björnham, Oscar

    2016-01-01

    Dynamic force spectroscopy (DFS) is an experimental technique that is commonly used to assess information of the strength, energy landscape, and lifetime of noncovalent bio-molecular interactions. DFS traditionally requires an applied force that increases linearly with time so that the bio-complex under investigation is exposed to a constant loading rate. However, tethers or polymers can modulate the applied force in a nonlinear regime. For example, bacterial adhesion pili and polymers with worm-like chain properties are examples of structures that show nonlinear force responses. In these situations, the theory for traditional DFS cannot be readily applied. In this work we expand the theory for DFS to also include nonlinear external forces while still maintaining compatibility with the linear DFS theory. To validate the theory we modeled a bio-complex expressed on a stiff, an elastic and a worm-like chain polymer, using Monte Carlo methods, and assessed the corresponding rupture force spectra. It was found th...

  18. Nonlinear optomechanical paddle nanocavities

    CERN Document Server

    Kaviani, Hamidreza; Wu, Marcelo; Ghobadi, Roohollah; Barclay, Paul E

    2014-01-01

    A photonic crystal optomechanical system combining strong nonlinear optomechanical coupling, low effective mass and large optical mode spacing is introduced. This nanoscale "paddle nanocavity" device supports mechanical resonances with effective mass of 300--600 fg which couple nonlinearly to co-localized optical modes with a quadratic optomechanical coupling coefficient $g^{(2)} > 2\\pi\\times400$ MHz/nm$^2$, and a two phonon to single photon optomechanical coupling rate $\\Delta \\omega_0 > 2\\pi\\times 16$ Hz. This coupling relies on strong phonon-photon interactions in a structure whose optical mode spectrum is highly non--degenerate. Simulations indicate that nonlinear optomechanical readout of thermally driven motion in these devices should be observable for T $> 50 $ mK, and that measurement of phonon shot noise is achievable.

  19. Nonlinear dynamics of structures

    CERN Document Server

    Oller, Sergio

    2014-01-01

    This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

  20. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    , leading to reduced mode confinement and dispersion flexibility. In this thesis, we treat the nonlinear photonic crystal fiber – a special sub-class of photonic crystal fibers, the core of which has a diameter comparable to the wavelength of the light guided in the fiber. The small core results in a large...... nonlinear coefficient and in various applications, it is therefore possible to reduce the required fiber lengths quite dramatically, leading to increased stability and efficiency. Furthermore, it is possible to design these fibers with zero-dispersion at previously unreachable wavelengths, paving the way...... for completely new applications, especially in and near the visible wavelength region. One such application is supercontinuum generation. Supercontinuum generation is extreme broadening of pulses in a nonlinear medium (in this case a small-core fiber), and depending on the dispersion of the fiber, it is possible...

  1. Linearizing nonlinear optics

    CERN Document Server

    Schmidt, Bruno E; Ernotte, Guilmot; Clerici, Matteo; Morandotti, Roberto; Ibrahim, Heide; Legare, Francois

    2016-01-01

    In the framework of linear optics, light fields do not interact with each other in a medium. Yet, when their field amplitude becomes comparable to the electron binding energies of matter, the nonlinear motion of these electrons emits new dipole radiation whose amplitude, frequency and phase differ from the incoming fields. Such high fields are typically achieved with ultra-short, femtosecond (1fs = 10-15 sec.) laser pulses containing very broad frequency spectra. Here, the matter not only couples incoming and outgoing fields but also causes different spectral components to interact and mix through a convolution process. In this contribution, we describe how frequency domain nonlinear optics overcomes the shortcomings arising from this convolution in conventional time domain nonlinear optics1. We generate light fields with previously inaccessible properties because the uncontrolled coupling of amplitudes and phases is turned off. For example, arbitrary phase functions are transferred linearly to the second har...

  2. Nonlinear optomechanics with graphene

    Science.gov (United States)

    Shaffer, Airlia; Patil, Yogesh Sharad; Cheung, Hil F. H.; Wang, Ke; Vengalattore, Mukund

    2016-05-01

    To date, studies of cavity optomechanics have been limited to exploiting the linear interactions between the light and mechanics. However, investigations of quantum signal transduction, quantum enhanced metrology and manybody physics with optomechanics each require strong, nonlinear interactions. Graphene nanomembranes are an exciting prospect for realizing such studies due to their inherently nonlinear nature and low mass. We fabricate large graphene nanomembranes and study their mechanical and optical properties. By using dark ground imaging techniques, we correlate their eigenmode shapes with the measured dissipation. We study their hysteretic response present even at low driving amplitudes, and their nonlinear dissipation. Finally, we discuss ongoing efforts to use these resonators for studies of quantum optomechanics and force sensing. This work is supported by the DARPA QuASAR program through a Grant from the ARO.

  3. Nonlinear Analysis of Buckling

    Directory of Open Access Journals (Sweden)

    Psotný Martin

    2014-06-01

    Full Text Available The stability analysis of slender web loaded in compression was presented. To solve this problem, a specialized computer program based on FEM was created. The nonlinear finite element method equations were derived from the variational principle of minimum of potential energy. To obtain the nonlinear equilibrium paths, the Newton-Raphson iteration algorithm was used. Corresponding levels of the total potential energy were defined. The peculiarities of the effects of the initial imperfections were investigated. Special attention was focused on the influence of imperfections on the post-critical buckling mode. The stable and unstable paths of the nonlinear solution were separated. Obtained results were compared with those gained using ANSYS system.

  4. Nonlinear Metamaterials for Holography

    CERN Document Server

    Almeida, Euclides; Prior, Yehiam

    2015-01-01

    A hologram is an optical element storing phase and possibly amplitude information enabling the reconstruction of a three dimensional image of an object by illumination and scattering of a coherent beam of light, and the image is generated at the same wavelength as the input laser beam. In recent years it was shown that information can be stored in nanometric antennas giving rise to ultrathin components. Here we demonstrate nonlinear multi-layer metamaterial holograms where by the nonlinear process of Third Harmonic Generation, a background free image is formed at a new frequency which is the third harmonic of the illuminating beam. Using e-beam lithography of multilayer plasmonic nanoantennas, we fabricate polarization-sensitive nonlinear elements such as blazed gratings, lenses and other computer-generated holograms. These holograms are analyzed and prospects for future device applications are discussed.

  5. Multidimensional nonlinear descriptive analysis

    CERN Document Server

    Nishisato, Shizuhiko

    2006-01-01

    Quantification of categorical, or non-numerical, data is a problem that scientists face across a wide range of disciplines. Exploring data analysis in various areas of research, such as the social sciences and biology, Multidimensional Nonlinear Descriptive Analysis presents methods for analyzing categorical data that are not necessarily sampled randomly from a normal population and often involve nonlinear relations. This reference not only provides an overview of multidimensional nonlinear descriptive analysis (MUNDA) of discrete data, it also offers new results in a variety of fields. The first part of the book covers conceptual and technical preliminaries needed to understand the data analysis in subsequent chapters. The next two parts contain applications of MUNDA to diverse data types, with each chapter devoted to one type of categorical data, a brief historical comment, and basic skills peculiar to the data types. The final part examines several problems and then concludes with suggestions for futu...

  6. Random point sets and their diffraction

    CERN Document Server

    Baake, Michael

    2010-01-01

    The diffraction of various random subsets of the integer lattice $\\mathbb{Z}^{d}$, such as the coin tossing and related systems, are well understood. Here, we go one important step beyond and consider random point sets in $\\mathbb{R}^{d}$. We present several systems with an effective stochastic interaction that still allow for explicit calculations of the autocorrelation and the diffraction measure. We concentrate on one-dimensional examples for illustrative purposes, and briefly indicate possible generalisations to higher dimensions. In particular, we discuss the stationary Poisson process in $\\mathbb{R}^{d}$ and the renewal process on the line. The latter permits a unified approach to a rather large class of one-dimensional structures, including random tilings. Moreover, we present some stationary point processes that are derived from the classical random matrix ensembles as introduced in the pioneering work of Dyson and Ginibre. Their re-consideration from the diffraction point of view improves the intuiti...

  7. Immobilizing Biomolecules Near the Diffraction Limit

    DEFF Research Database (Denmark)

    Skovsen, Esben; Petersen, Maria Teresa Neves; Gennaro, Ane Kold Di

    2009-01-01

    Our group has previously shown that biomolecules containing disulfide bridges in close proximity to aromatic residues can be immobilized, through covalent bonds, onto thiol derivatized surfaces upon UV excitation of the aromatic residue(s). We have also previously shown that our new technology can...... be used to print arrays of biomolecules and to immobilize biomolecules according to any specific pattern on a planar substrates with micrometer scale resolution. In this paper we show that we can immobilize proteins according to diffraction patterns of UV light. We also show that the feature size...... of the immobilized patterns can be as small as the diffraction limit for the excitation light, and that the immobilized patterns correspond to the diffraction pattern used to generate it. The flexibility of this new technology will in principle make it possible to create any pattern of biomolecules onto a substrate...

  8. Diffractive elements performance in chromatic confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, J; Duque, D; Alean, A; Toledo, M [Grupo de Optica y EspectroscopIa, Centro de Ciencia Basica, Universidad Pontificia Bolivariana. Medellin (Colombia); Meneses, J [Laboratorio de Optica y Tratamiento de Senales, Instituto de Fisica, Universidad Industrial de Santander, Bucaramanga (Colombia); Gharbi, T, E-mail: jgarzonr10@une.net.co [Laboratoire d' Optique P. M. Duffieux, UMR-6603 CNR/Universite de Franche-Comte. 16 route de Gray, 25030 Besancon Cedex (France)

    2011-01-01

    The Confocal Laser Scanning Microscopy (CLSM) has been widely used in the semiconductor industry and biomedicine because of its depth discrimination capability. Subsequent to this technique has been developed in recent years Chromatic Confocal Microscopy. This method retains the same principle of confocal and offers the added advantage of removing the axial movement of the moving system. This advantage is usually accomplished with an optical element that generates a longitudinal chromatic aberration and a coding system that relates the axial position of each point of the sample with the wavelength that is focused on each. The present paper shows the performance of compact chromatic confocal microscope when some different diffractive elements are used for generation of longitudinal chromatic aberration. Diffractive elements, according to the process and manufacturing parameters, may have different diffraction efficiency and focus a specific wavelength in a specific focal position. The performance assessment is carried out with various light sources which exhibit an incoherent behaviour and a broad spectral width.

  9. Higher order diffractions from a circular disk

    Science.gov (United States)

    Marsland, Diane P.; Balanis, Constantine A.; Brumley, Stephen A.

    1987-12-01

    The backscattering from a circular disk is analyzed using the geometrical theory of diffraction. First-, second-, and third-order diffractions are included in the hard polarization analysis, while first-, second-, and third-order slope diffractions are included for soft polarization. Improvements in the prediction of the monostatic radar cross section over previous works are noted. For hard polarization, an excellent agreement is exhibited between experimental and theoretical results, while a very good agreement is noted for soft polarization. To further improve the soft polarization results for wide angles, a model for the creeping wave or circulating current on the edge of the disk is obtained and used to find an additional component of the backscattered field. The addition of this component significantly improves the results for wide angles, leading to excellent agreement for soft polarization also. An axial-caustic correction method using equivalent currents is also included in the analysis.

  10. Diffractive hadronic production of D mesons

    Energy Technology Data Exchange (ETDEWEB)

    MacKay, William Wallace [Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Physcis

    1980-01-01

    This thesis reports on data taken in experiment E369 using the Chicago Cyclotron Spectrometer at Fermilab. A search for charmed D mesons was made using a beam of 217 GeV π- incident on a liquid hydrogen target. The trigger required a recoil proton and a prompt muon. A total of 50 ± 12 charged D events were seen in the K±ππ channels and were split between the two channels in about equal amounts. Cuts were made which selected diffractive events, but when these cuts were removed the signal remained the same although the background was greatly increased. The Feynman x and angular distributions were consistent with diffractive production. A diffractive model yields a cross section of (6 -10) + 4 µb.

  11. Electron backscatter diffraction in materials characterization

    Directory of Open Access Journals (Sweden)

    Dejan Stojakovic

    2012-03-01

    Full Text Available Electron Back-Scatter Diffraction (EBSD is a powerful technique that captures electron diffraction patterns from crystals, constituents of material. Captured patterns can then be used to determine grain morphology, crystallographic orientation and chemistry of present phases, which provide complete characterization of microstructure and strong correlation to both properties and performance of materials. Key milestones related to technological developments of EBSD technique have been outlined along with possible applications using modern EBSD system. Principles of crystal diffraction with description of crystallographic orientation, orientation determination and phase identification have been described. Image quality, resolution and speed, and system calibration have also been discussed. Sample preparation methods were reviewed and EBSD application in conjunction with other characterization techniques on a variety of materials has been presented for several case studies. In summary, an outlook for EBSD technique was provided.

  12. Forward energy flow and diffraction at ATLAS

    CERN Document Server

    Staroba, P; The ATLAS collaboration

    2012-01-01

    First measurements of forward energy flow and diffractive dissociation processes at ATLAS are presented. Measurements are based on 7 TeV minimum bias (7.1μb−1) and dijet (585μb−1) data samples taken during March-May 2010 in the low pileup accelerator setup. Measurement of transverse energy density as a function of pseudorapidity was performed using the full acceptance of ATLAS detectors. Stable charged particles with PT > 500 MeV and stable neutral particles with PT > 200 MeV were included. Manifestation of diffractive processes of three classes (single, double and central diffractive dissociation) was studied using inelastic differential cross section in forward rapidity gap size ΔηF bins. Experimental distributions are compared with several Monte Carlo predictions (PYTHIA6, PYTHIA8, PHOJET, HERWIG++ and EPOS) using different tunes.

  13. Coherent Diffractive Imaging Using Randomly Coded Masks

    CERN Document Server

    Seaberg, Matthew H; Turner, Joshua J

    2015-01-01

    Coherent diffractive imaging (CDI) provides new opportunities for high resolution X-ray imaging with simultaneous amplitude and phase contrast. Extensions to CDI broaden the scope of the technique for use in a wide variety of experimental geometries and physical systems. Here, we experimentally demonstrate a new extension to CDI that encodes additional information through the use of a series of randomly coded masks. The information gained from the few additional diffraction measurements removes the need for typical object-domain constraints; the algorithm uses prior information about the masks instead. The experiment is performed using a laser diode at 532.2 nm, enabling rapid prototyping for future X-ray synchrotron and even free electron laser experiments. Diffraction patterns are collected with up to 15 different masks placed between a CCD detector and a single sample. Phase retrieval is performed using a convex relaxation routine known as "PhaseCut" followed by a variation on Fienup's input-output algorit...

  14. Small angle electron diffraction and deflection

    Directory of Open Access Journals (Sweden)

    T. Koyama

    2012-03-01

    Full Text Available Electron optical system is constructed in order to obtain small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 radian in the reciprocal space. Long-distance camera length up to 3000 m is achieved in a conventional transmission electron microscope with LaB6 thermal emission type. The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited in Permalloy elements. A simultaneous recording of electron diffraction and Lorentz deflection is also demonstrated in 180 degree striped magnetic domains of La0.825Sr0.175MnO3.

  15. Double diffraction in an atomic gravimeter

    CERN Document Server

    Malossi, Nicola; Merlet, Sébastien; Landragin, Arnaud; Santos, Franck Pereira Dos

    2009-01-01

    We demonstrate the realization of a new scheme for cold atom gravimetry based on the use of double diffraction beamsplitters recently demonstrated in \\cite{Leveque}, where the use of two retro-reflected Raman beams allows symmetric diffraction in $\\pm \\hbar k_{eff}$ momenta. Though in principle restricted to the case of zero Doppler shift, for which the two pairs of Raman beams are simultaneously resonant, we demonstrate that such diffraction pulses can remain efficient on atoms with non zero velocity, such as in a gravimeter, when modulating the frequency of one of the two Raman laser sources. We use such pulses to realize an interferometer insensitive to laser phase noise and some of the dominant systematics. This reduces the technical requirements and would allow the realization of a simple atomic gravimeter. We demonstrate a sensitivity of $1.2\\times10^{-7}g$ per shot.

  16. Diffraction and interference of walking drops

    Science.gov (United States)

    Pucci, Giuseppe; Harris, Daniel M.; Bush, John W. M.

    2016-11-01

    A decade ago, Yves Couder and Emmanuel Fort discovered a wave-particle association on the macroscopic scale: a drop can bounce indefinitely on a vibrating bath of the same liquid and can be piloted by the waves that it generates. These walking droplets have been shown to exhibit several quantum-like features, including single-particle diffraction and interference. Recently, the original diffraction and interference experiments of Couder and Fort have been revisited and contested. We have revisited this system using an improved experimental set-up, and observed a strong dependence of the behavior on system parameters, including drop size and vibrational forcing. In both the single- and the double-slit geometries, the diffraction pattern is dominated by the interaction of the walking droplet with a planar boundary. Critically, in the double-slit geometry, the walking droplet is influenced by both slits by virtue of its spatially extended wave field. NSF support via CMMI-1333242.

  17. Diffractive ρ production at small x in future electron-ion colliders

    Science.gov (United States)

    Gonçalves, V. P.; Navarra, F. S.; Spiering, D.

    2016-09-01

    The future electron-ion (eA) collider is expected to probe the high energy regime of the quantum chromodynamics (QCD), with the exclusive vector meson production cross section being one of the most promising observables. In this paper we complement previous studies of exclusive processes presenting a comprehensive analysis of diffractive ρ production at small x. We compute the coherent and incoherent cross sections taking into account non-linear QCD dynamical effects and considering different models for the dipole-proton scattering amplitude and vector meson wave function. The dependence of these cross sections on the energy, photon virtuality, nuclear mass number and squared momentum transfer is analysed in detail. Moreover, we compare the non-linear predictions with those obtained in the linear regime. Finally, we also estimate the exclusive photon, J/{{\\Psi }} and ϕ production and compare with the results obtained for ρ production. Our results demonstrate that the analysis of diffractive ρ production in future electron-ion colliders will be important in understanding the non-linear QCD dynamics.

  18. Nonlinear airship aeroelasticity

    Science.gov (United States)

    Bessert, N.; Frederich, O.

    2005-12-01

    The aeroelastic derivatives for today's aircraft are calculated in the concept phase using a standard procedure. This scheme has to be extended for large airships, due to various nonlinearities in structural and aerodynamic behaviour. In general, the structural model of an airship is physically as well as geometrically nonlinear. The main sources of nonlinearity are large deformations and the nonlinear material behaviour of membranes. The aerodynamic solution is also included in the nonlinear problem, because the deformed airship influences the surrounding flow. Due to these nonlinearities, the aeroelastic problem for airships can only be solved by an iterative procedure. As one possibility, the coupled aerodynamic and structural dynamic problem was handled using linked standard solvers. On the structural side, the Finite-Element program package ABAQUS was extended with an interface to the aerodynamic solver VSAERO. VSAERO is based on the aerodynamic panel method using potential flow theory. The equilibrium of the internal structural and the external aerodynamic forces leads to the structural response and a trimmed flight state for the specified flight conditions (e.g. speed, altitude). The application of small perturbations around a trimmed state produces reaction forces and moments. These constraint forces are then transferred into translational and rotational acceleration fields by performing an inertia relief analysis of the disturbed structural model. The change between the trimmed flight state and the disturbed one yields the respective aeroelastic derivatives. By including the calculated derivatives in the linearised equation of motion system, it is possible to judge the stability and controllability of the investigated airship.

  19. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2012-01-01

    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  20. Limits to Nonlinear Inversion

    DEFF Research Database (Denmark)

    Mosegaard, Klaus

    2012-01-01

    For non-linear inverse problems, the mathematical structure of the mapping from model parameters to data is usually unknown or partly unknown. Absence of information about the mathematical structure of this function prevents us from presenting an analytical solution, so our solution depends on our......-heuristics are inefficient for large-scale, non-linear inverse problems, and that the 'no-free-lunch' theorem holds. We discuss typical objections to the relevance of this theorem. A consequence of the no-free-lunch theorem is that algorithms adapted to the mathematical structure of the problem perform more efficiently than...

  1. Fundamentals of nonlinear optics

    CERN Document Server

    Powers, Peter E

    2011-01-01

    Peter Powers's rigorous but simple description of a difficult field keeps the reader's attention throughout. … All chapters contain a list of references and large numbers of practice examples to be worked through. … By carefully working through the proposed problems, students will develop a sound understanding of the fundamental principles and applications. … the book serves perfectly for an introductory-level course for second- and third-order nonlinear optical phenomena. The author's writing style is refreshing and original. I expect that Fundamentals of Nonlinear Optics will fast become pop

  2. Tunable nonlinear graphene metasurfaces

    CERN Document Server

    Smirnova, Daria A; Kivshar, Yuri S; Khanikaev, Alexander B

    2015-01-01

    We introduce the concept of nonlinear graphene metasurfaces employing the controllable interaction between a graphene layer and a planar metamaterial. Such hybrid metasurfaces support two types of subradiant resonant modes, asymmetric modes of structured metamaterial elements ("metamolecules") and graphene plasmons exhibiting strong mutual coupling and avoided dispersion crossing. High tunability of graphene plasmons facilitates strong interaction between the subradiant modes, modifying the spectral position and lifetime of the associated Fano resonances. We demonstrate that strong resonant interaction, combined with the subwavelength localization of plasmons, leads to the enhanced nonlinear response and high efficiency of the second-harmonic generation.

  3. Single Particle X-ray Diffractive Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bogan, M J; Benner, W H; Boutet, S; Rohner, U; Frank, M; Seibert, M; Maia, F; Barty, A; Bajt, S; Riot, V; Woods, B; Marchesini, S; Hau-Riege, S P; Svenda, M; Marklund, E; Spiller, E; Hajdu, J; Chapman, H N

    2007-10-01

    In nanotechnology, strategies for the creation and manipulation of nanoparticles in the gas phase are critically important for surface modification and substrate-free characterization. Recent coherent diffractive imaging with intense femtosecond X-ray pulses has verified the capability of single-shot imaging of nanoscale objects at sub-optical resolutions beyond the radiation-induced damage threshold. By intercepting electrospray-generated particles with a single 15 femtosecond soft-X-ray pulse, we demonstrate diffractive imaging of a nanoscale specimen in free flight for the first time, an important step toward imaging uncrystallized biomolecules.

  4. Glancing angle synchrotron X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Cernik, R.J. [Daresbury Lab., Warrington, WA (United States)

    1996-09-01

    This paper describes in basic detail some of the techniques that can be used to study thin films and surfaces. These are all in the X-ray region and cover reflectivity, diffraction form polycrystalline films, textured films and single crystal films. Other effects such as fluorescence and diffuse scattering are mentioned but not discussed in detail. Two examples of the reflectivity from multilayers and the diffraction from iron oxide films are discussed. The advantages of the synchrotron for these studies is stressed and the experimental geometries that can be employed are described i detail. A brief bibliography is provided at the end to accompany this part of the 1996 Frascati school.

  5. Film thickness determination by grazing incidence diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Battiston, G. A.; Gerbasi, R. [CNR, Padua (Italy). Istituto di Chimica e Tecnologie Inorganiche e dei Materiali Avanzati

    1996-09-01

    Thin films deposited via MOCVD (Metal Organic Chemical Vapour Deposition) are layers in the thickness range of a few manometers to about ten micrometers. An understanding of the physics and chemistry of films is necessary for a better comprehension of the phenomena involved in the film deposition procedure and its optimisation. Together with the crystalline phase a parameter that must be determined is the thickness of the layer. In this work the authors present a method for the measurement of the film thickness. This procedure, based on diffraction intensity absorption of the X-rays, both incident and diffracted in passing through the layers, resulted quite simple, rapid and non-destructive.

  6. Diffraction manipulation by four-wave mixing

    CERN Document Server

    Katzir, Itay; Firstenberg, Ofer

    2014-01-01

    We suggest a scheme to manipulate paraxial diffraction by utilizing the dependency of a four-wave mixing process on the relative angle between the light fields. A microscopic model for four-wave mixing in a Lambda-type level structure is introduced and compared to recent experimental data. We show that images with feature size as low as 10 micrometers can propagate with very little or even negative diffraction. The inherent gain prevents loss and allows for operating at high optical depths. Our scheme does not rely on atomic motion and is thus applicable to both gaseous and solid media.

  7. Atoms in static fields Chaos or Diffraction?

    CERN Document Server

    Dando, P A

    1998-01-01

    A brief review of the manifestations of classical chaos observed in atomic systems is presented. Particular attention is paid to the analysis of atomic spectra by periodic orbit-type theories. For diamagnetic non-hydrogenic Rydberg atoms, the dynamical explanation for observed spectral features has been disputed. By building on our previous work on the photoabsorption spectrum, we show how, by the addition of diffractive terms, the spectral fluctuations in the energy level spectrum of general Rydberg atoms can be obtained with remarkable precision from the Gutzwiller trace formula. This provides further evidence that non-hydrogenic systems are most naturally described in terms of diffraction rather than classical chaos.

  8. Factorization breaking in diffractive dijet photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Centre National de la Recherche Scientifique, 38 - Grenoble (France). Univ. Joseph Fourier, Lab. de Physique Subatomique et de Cosmologie; Kramer, G. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2004-08-01

    We have calculated the diffractive dijet cross section in low-Q{sup 2} ep scattering in the HERA regime. The results of the calculation in LO and NLO are compared to recent experimental data of the H1 collaboration. We find that in LO the calculated cross sections are in reasonable agreement with the experimental results. In NLO, however, some of the cross sections disagree, showing that factorization breaking occurs in that order. By suppressing the resolved contribution by a factor of approximately three, good agreement with all the data is found. The size of the factorization breaking effects in diffractive dijet photoproduction agrees well with absorptive model predictions. (orig.)

  9. Factorization breaking in diffractive dijet photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Universite Joseph Fourier, CNRS-IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Universitaet Hamburg, II. Institut fuer Theoretische Physik, Hamburg (Germany); Kramer, G. [Universitaet Hamburg, II. Institut fuer Theoretische Physik, Hamburg (Germany)

    2004-12-01

    We have calculated the diffractive dijet cross section in low-Q{sup 2} ep scattering in the HERA regime. The results of the calculation in LO and NLO are compared to recent experimental data of the H1 Collaboration. We find that in LO the calculated cross sections are in reasonable agreement with the experimental results. In NLO, however, some of the cross sections disagree, showing that factorization breaking occurs in that order. By suppressing the resolved contribution by a factor of approximately three, good agreement with all the data is found. The size of the factorization breaking effects in diffractive dijet photoproduction agrees well with absorptive model predictions. (orig.)

  10. Diffraction of sound by nearly rigid barriers

    Science.gov (United States)

    Hadden, W. J., Jr.; Pierce, A. D.

    1976-01-01

    The diffraction of sound by barriers with surfaces of large, but finite, acoustic impedance was analyzed. Idealized source-barrier-receiver configurations in which the barriers may be considered as semi-infinite wedges are discussed. Particular attention is given to situations in which the source and receiver are at large distances from the tip of the wedge. The expression for the acoustic pressure in this limiting case is compared with the results of Pierce's analysis of diffraction by a rigid wedge. An expression for the insertion loss of a finite impedance barrier is compared with insertion loss formulas which are used extensively in selecting or designing barriers for noise control.

  11. Focusing of light beyond the diffraction limit

    CERN Document Server

    Chen, K R

    2009-01-01

    Diffraction limits the behaviour of light in optical systems and sets the smallest achievable line width at half the wavelength. With a novel subwavelength plasmonic lens to reduce the diffraction via an asymmetry and to generate and squeeze the wave functions, an incident light is focused by the aperture to a single-line with its width beyond the limit outside the near zone. The fields focused are radiative and capable of propagating to the far zone. The light focusing process, besides being of academic interest, is expected to open up a wide range of application possibilities.

  12. Wave diffraction by a cosmic string

    CERN Document Server

    Fernández-Núñez, Isabel

    2016-01-01

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects.

  13. Parabolic non-diffracting beams: geometrical approach

    Science.gov (United States)

    Sosa-Sánchez, Citlalli Teresa; Silva-Ortigoza, Gilberto; Alejandro Juárez-Reyes, Salvador; de Jesús Cabrera-Rosas, Omar; Espíndola-Ramos, Ernesto; Julián-Macías, Israel; Ortega-Vidals, Paula

    2017-08-01

    The aim of this work is to present a geometrical characterization of parabolic non-diffracting beams. To this end, we compute the corresponding angular spectrum of the separable non-diffracting parabolic beams in order to determine the one-parameter family of solutions of the eikonal equation associated with this type of beam. Using this information, we compute the corresponding wavefronts and caustic, and find that qualitatively the caustic corresponds to the maximum of the intensity pattern and the wavefronts are deformations of conical surfaces.

  14. Wave diffraction by a cosmic string

    Science.gov (United States)

    Fernández-Núñez, Isabel; Bulashenko, Oleg

    2016-08-01

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects.

  15. Nonlinear effects in optical fibers

    CERN Document Server

    Ferreira, Mario F

    2011-01-01

    Cutting-edge coverage of nonlinear phenomena occurring inside optical fibers Nonlinear fiber optics is a specialized part of fiber optics dealing with optical nonlinearities and their applications. As fiber-optic communication systems have become more advanced and complex, the nonlinear effects in optical fibers have increased in importance, as they adversely affect system performance. Paradoxically, the same nonlinear phenomena also offer the promise of addressing the bandwidth bottleneck for signal processing for future ultra-high speed optical networks. Nonlinear Effects in Optical Fiber

  16. High throughput optoelectronic smart pixel systems using diffractive optics

    Science.gov (United States)

    Chen, Chih-Hao

    1999-12-01

    algorithm to design Diffractive Optical Elements (DOEs) having higher uniformity and better signal-to-noise ratio. The algorithm is based on nonlinear least-square optimization procedures and phase-shifting quantization scheme to minimize the reconstruction error of DOEs. We also describe a modified diffractive microlens design algorithm to overcome linewidth limitations in fabrication while achieving higher numerical aperture and better power efficiency. Several diffractive optical devices used in our smart pixel systems, including microlens arrays and spot array generators, are designed by these algorithms, and have been fabricated and characterized for system integration.

  17. High-order finite difference solution for 3D nonlinear wave-structure interaction

    DEFF Research Database (Denmark)

    Ducrozet, Guillaume; Bingham, Harry B.; Engsig-Karup, Allan Peter;

    2010-01-01

    This contribution presents our recent progress on developing an efficient fully-nonlinear potential flow model for simulating 3D wave-wave and wave-structure interaction over arbitrary depths (i.e. in coastal and offshore environment). The model is based on a high-order finite difference scheme...... OceanWave3D presented in [1, 2]. A nonlinear decomposition of the solution into incident and scattered fields is used to increase the efficiency of the wave-structure interaction problem resolution. Application of the method to the diffraction of nonlinear waves around a fixed, bottom mounted circular...

  18. Nonlinear elliptic systems with exponential nonlinearities

    Directory of Open Access Journals (Sweden)

    Said El Manouni

    2002-12-01

    Full Text Available In this paper we investigate the existence of solutions for {gather*} -mathop{m div}( a(| abla u | ^N| abla u |^{N-2}u = f(x,u,v quad mbox{in } Omega -mathop{m div}(a(| abla v| ^N| abla v |^{N-2}v = g(x,u,v quad mbox{in } Omega u(x = v(x = 0 quad mbox{on }partial Omega. end{gather*} Where $Omega$ is a bounded domain in ${mathbb{R}}^N$, $Ngeq 2$, $f$ and $g$ are nonlinearities having an exponential growth on $Omega$ and $a$ is a continuous function satisfying some conditions which ensure the existence of solutions.

  19. Nonlinearity and disorder: Classification and stability of nonlinear impurity modes

    DEFF Research Database (Denmark)

    Sukhorukov, Andrey A.; Kivshar, Yuri S.; Bang, Ole

    2001-01-01

    We study the effects produced by competition of two physical mechanisms of energy localization in inhomogeneous nonlinear systems. As an example, we analyze spatially localized modes supported by a nonlinear impurity in the generalized nonlinear Schrödinger equation and describe three types of no...

  20. Generalized Nonlinear Yule Models

    Science.gov (United States)

    Lansky, Petr; Polito, Federico; Sacerdote, Laura

    2016-10-01

    With the aim of considering models related to random graphs growth exhibiting persistent memory, we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macroevolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth rates. Among the main results we derive the explicit distribution of the number of in-links of a webpage chosen uniformly at random recognizing the contribution to the asymptotics and the finite time correction. The mean value of the latter distribution is also calculated explicitly in the most general case. Furthermore, in order to show the usefulness of our results, we particularize them in the case of specific birth rates giving rise to a saturating behaviour, a property that is often observed in nature. The further specialization to the non-fractional case allows us to extend the Yule model accounting for a nonlinear growth.

  1. Nonlinear Regression with R

    CERN Document Server

    Ritz, Christian; Parmigiani, Giovanni

    2009-01-01

    R is a rapidly evolving lingua franca of graphical display and statistical analysis of experiments from the applied sciences. This book provides a coherent treatment of nonlinear regression with R by means of examples from a diversity of applied sciences such as biology, chemistry, engineering, medicine and toxicology.

  2. Methods of nonlinear kinetics

    OpenAIRE

    Gorban, A. N.; Karlin, I.V.

    2003-01-01

    Nonlinear kinetic equations are reviewed for a wide audience of specialists and postgraduate students in physics, mathematical physics, material science, chemical engineering and interdisciplinary research. Contents: The Boltzmann equation, Phenomenology and Quasi-chemical representation of the Boltzmann equation, Kinetic models, Discrete velocity models, Direct simulation, Lattice Gas and Lattice Boltzmann models, Minimal Boltzmann models for flows at low Knudsen number, Other kinetic equati...

  3. Intramolecular and nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.J. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

  4. Nonlinear Hamiltonian systems

    DEFF Research Database (Denmark)

    Jørgensen, Michael Finn

    1995-01-01

    It is generally very difficult to solve nonlinear systems, and such systems often possess chaotic solutions. In the rare event that a system is completely solvable, it is said to integrable. Such systems never have chaotic solutions. Using the Inverse Scattering Transform Method (ISTM) two...

  5. Nonlinear phased array imaging

    Science.gov (United States)

    Croxford, Anthony J.; Cheng, Jingwei; Potter, Jack N.

    2016-04-01

    A technique is presented for imaging acoustic nonlinearity within a specimen using ultrasonic phased arrays. Acoustic nonlinearity is measured by evaluating the difference in energy of the transmission bandwidth within the diffuse field produced through different focusing modes. The two different modes being classical beam forming, where delays are applied to different element of a phased array to physically focus the energy at a single location (parallel firing) and focusing in post processing, whereby one element at a time is fired and a focused image produced in post processing (sequential firing). Although these two approaches are linearly equivalent the difference in physical displacement within the specimen leads to differences in nonlinear effects. These differences are localized to the areas where the amplitude is different, essentially confining the differences to the focal point. Direct measurement at the focal point are however difficult to make. In order to measure this the diffuse field is used. It is a statistical property of the diffuse field that it represents the total energy in the system. If the energy in the diffuse field for both the sequential and parallel firing case is measured then the difference between these, within the input signal bandwidth, is largely due to differences at the focal spot. This difference therefore gives a localized measurement of where energy is moving out of the transmission bandwidth due to nonlinear effects. This technique is used to image fatigue cracks and other damage types undetectable with conventional linear ultrasonic measurements.

  6. Generalized Nonlinear Yule Models

    Science.gov (United States)

    Lansky, Petr; Polito, Federico; Sacerdote, Laura

    2016-11-01

    With the aim of considering models related to random graphs growth exhibiting persistent memory, we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macroevolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth rates. Among the main results we derive the explicit distribution of the number of in-links of a webpage chosen uniformly at random recognizing the contribution to the asymptotics and the finite time correction. The mean value of the latter distribution is also calculated explicitly in the most general case. Furthermore, in order to show the usefulness of our results, we particularize them in the case of specific birth rates giving rise to a saturating behaviour, a property that is often observed in nature. The further specialization to the non-fractional case allows us to extend the Yule model accounting for a nonlinear growth.

  7. Trirefringence in nonlinear metamaterials

    CERN Document Server

    De Lorenci, Vitorio A

    2012-01-01

    We study the propagation of electromagnetic waves in the limit of geometrical optics for a class of nearly transparent nonlinear uniaxial metamaterials for which their permittivity tensors present a negative principal component. Their permeability are assumed positive and dependent on the electric field. We show that light waves experience triple refraction -- trirefringence. Additionally to the ordinary wave, two extraordinary waves propagate in such media.

  8. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  9. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

    Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.

    2010-01-01

    , provides a background to the associated nonlinear optical processes, treats the generation mechanisms from continuous wave to femtosecond pulse pump regimes and highlights the diverse applications. A full discussion of numerical methods and comprehensive computer code are also provided, enabling readers...

  10. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  11. Is this scaling nonlinear?

    CERN Document Server

    Leitao, J C; Gerlach, M; Altmann, E G

    2016-01-01

    One of the most celebrated findings in complex systems in the last decade is that different indexes y (e.g., patents) scale nonlinearly with the population~x of the cities in which they appear, i.e., $y\\sim x^\\beta, \\beta \

  12. Nonlinear Gravitational Lagrangians revisited

    CERN Document Server

    Magnano, Guido

    2016-01-01

    The Legendre transformation method, applied in 1987 to deal with purely metric gravitational Lagrangians with nonlinear dependence on the Ricci tensor, is extended to metric-affine models and is shown to provide a concise and insightful comparison of the dynamical content of the two variational frameworks.

  13. Nonlinearities in Microwave Superconductivity

    OpenAIRE

    Ledenyov, Dimitri O.; Ledenyov, Viktor O.

    2012-01-01

    The research is focused on the modeling of nonlinear properties of High Temperature Superconducting (HTS) thin films, using Bardeen, Cooper, Schrieffer and Lumped Element Circuit theories, with purpose to enhance microwave power handling capabilities of microwave filters and optimize design of microwave circuits in micro- and nano- electronics.

  14. Nonlinear tsunami generation mechanism

    Directory of Open Access Journals (Sweden)

    M. A. Nosov

    2001-01-01

    Full Text Available The nonlinear mechanism of long gravitational surface water wave generation by high-frequency bottom oscillations in a water layer of constant depth is investigated analytically. The connection between the surface wave amplitude and the parameters of bottom oscillations and source length is investigated.

  15. Topics in Nonlinear Dynamics

    DEFF Research Database (Denmark)

    Mosekilde, Erik

    Through a significant number of detailed and realistic examples this book illustrates how the insights gained over the past couple of decades in the fields of nonlinear dynamics and chaos theory can be applied in practice. Aomng the topics considered are microbiological reaction systems, ecological...

  16. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias

    2013-01-01

    nonlinearity in doped semiconductors originates from the near-instantaneous heating of free electrons in the ponderomotive potential created by electric field of the THz pulse, leading to ultrafast increase of electron effective mass by intervalley scattering. Modification of effective mass in turn leads...

  17. Non-Diffracting Waves: A new introduction

    CERN Document Server

    Recami, E; Hernandez-Figuera, H E; Ambrosio, L A

    2014-01-01

    This work deals with exact solutions to the wave equations. We start by introducing the Non-Diffracting Waves (NDW), and by a definition of NDWs. Afterwards we recall -besides ordinary waves (gaussian beams, gaussian pulses)- the simplest non diffracting waves (Bessel beams, X-shaped pulses,...). In Sec.2 we show how to eliminate any backward-traveling components, first in the case of ideal NDW pulses, and then, in Sec.3, for realistic finite-energy NDW pulses. In particular, in subsec.3.1 we forward a general functional expression for any totally-forward non-diffracting pulses. Then, in Sec.4 an efficient method is set forth for the analytic description of truncated beams, a byproduct of its being the elimination of any need of lengthy numerical calculations. In Sec.5 we explore the question of the subluminal NDWs, or bullets, in terms of two different methods, the second one allowing the analytic description of non-diffracting waves with a static envelope ("Frozen Waves", FW), in terms of continuous Bessel ...

  18. Diffraction in ALICE and trigger efficiencies

    CERN Document Server

    Navin, Sparsh; Lietava, Roman

    ALICE is built to measure the properties of strongly interacting matter created in heavy-ion collisions. In addition, taking advantage of the low pT acceptance in the central barrel, ALICE is playing an important role in understanding pp collisions with minimum bias triggers at LHC energies. The work presented in this thesis is based on pp data simulated by the ALICE collaboration and early data collected at a center-of-mass energy of 7 TeV. A procedure to calculate trigger efficiencies and an estimate of the systematic uncertainty due to the limited acceptance of the detector are shown. A kinematic comparison between Monte Carlo event generators, PYTHIA 6, PYTHIA 8 and PHOJET is also presented. To improve the description of diffraction in PYTHIA, a hard diffractive component was added to PYTHIA 8 in 2009, which is described. Finally a trigger with a high efficiency for picking diffractive events is used to select a sample with an enhanced diffractive component from pp data. These data are compared to Monte ...

  19. Diffractive Pedagogies: Dancing across New Materialist Imaginaries

    Science.gov (United States)

    Hickey-Moody, Anna; Palmer, Helen; Sayers, Esther

    2016-01-01

    We theorise an interdisciplinary arts practice university course and consider the forms of educational imaginary challenged by our curriculum. We argue for the disruptive and generative potential of what we call diffractive pedagogy as an example of the type of learning that can take place when materiality and entanglement are considered as vital…

  20. Diffraction Anomalous Near-Edge Structure

    Science.gov (United States)

    Moltaji, Habib O., Jr.

    1995-11-01

    To determine the atomic structure about atom of an element in a sample of a condensed multicomponent single crystal, contrast radiation is proposed with the use of Diffraction Anomalous Near-Edge Structure (DANES), which combines the long-range order sensitivity of the x-ray diffraction and short-range order of the x-ray absorption near-edge techniques. This is achieved by modulating the photon energy of the x-ray beam incident on the sample over a range of energies near an absorption edge of the selected element. Due to anomalous dispersion, x-ray diffraction, and x-ray absorption, the DANES intensity with respect to the selected element is obtained in a single experiment. I demonstrate that synchrotron DANES measurements for the single crystal of thin film and the powder samples and provide the same local atomic structural information as the x-ray absorption near-edge with diffraction condition and can be used to provide enhanced site selectivity. I demonstrate calculations of DAFS intensity and measurements of polarized DANES and XANES intensity.

  1. Diffractive leptoproduction of small masses in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Gotsman, Errol; Maor, Uri [Tel Aviv Univ. (Israel). Raymond and Sackler Faculty of Exact Sciences. School of Physics and Astronomy; Levin, Eugene [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Petersburg Nuclear Physics Inst., St. Petersburg (Russian Federation). Theory Dept.

    1996-05-01

    In this paper we consider the process of diffraction dissociation in deeply inelastic scattering in the region of small produced mass, which we define as production of q-bar q-pair and q-bar q G system in the final state. We show that the small distance contributions (r perpendicular is proportional to 1/Q) to the longitudinal polarised virtual photon dominate. Formulae for the cross section using the gluon structure function are written within the framework of perturbative QCD. It is shown that the production of small masses by the transverse polarized photo is concentrated at moderate values of r perpendicular to {approx} 1 GeV{sup -1}, where the p QCD approach can be applied. This could be responsible for a considerable part of the diffractive production. It is shown that only q-bar q pair production contribute to the diffraction dissociation at {beta} > 0.4, the possibility to extract the value of the gluon structure function from the measurements in this kinematic region is discussed. The evolution of the DD structure function is studied, and a solution to the DD evolution equations is proposed. Shadowing corrections are discussed for both the transverse and longitudinal polarised photon, and estimates of the different damping factors are given. The relation between diffractive production and the corrections to F2, is alluded to. (author). 45 refs., 16 figs.

  2. GENERALIZED FRESNEL DIFFRACTION INTEGRAL AND ITS APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    YANG JUN; FAN DIAN-YUAN; WANG SHI-JI; GU YUAN

    2000-01-01

    Within the generalized definition of ABCDGH matrices, the conventional ABCDGH diffraction integral is ex-tended for a misaligned complex paraxial system with a curved optical axis. On this basis the transformation lawfor Gaussian-Schell model beams through an ABCDGH systems is derived, the propagation behavior of the mutualcoherence function through ABCDGH systems in the presence of random media is investigated as well.

  3. Doubly diffracted ray from a hard quarterplane

    DEFF Research Database (Denmark)

    Albertsen, Niels Christian

    2000-01-01

    The scattering of the electromagnetic field from a half wave dipole source around a quarterplane can be calculated from the solutions to two scalar problems, one with a soft quarterplane and one with a hard quarterplane. In both cases, a doubly diffracted ray may exist, but only in the case of th...

  4. A Study of Simple Diffraction Models

    DEFF Research Database (Denmark)

    Agerkvist, Finn

    1997-01-01

    Three different models for calculating edge diffraction are examined. The methods of Vanderkooy, Terai and Biot & Tolstoy are compared with measurements. Although a good agreement is obtained, the measurements also show that none of the methods work completely satisfactorily. The desired properties...

  5. Accessing the diffracted wavefield by coherent subtraction

    Science.gov (United States)

    Schwarz, Benjamin; Gajewski, Dirk

    2017-10-01

    Diffractions have unique properties which are still rarely exploited in common practice. Aside from containing subwavelength information on the scattering geometry or indicating small-scale structural complexity, they provide superior illumination compared to reflections. While diffraction occurs arguably on all scales and in most realistic media, the respective signatures typically have low amplitudes and are likely to be masked by more prominent wavefield components. It has been widely observed that automated stacking acts as a directional filter favouring the most coherent arrivals. In contrast to other works, which commonly aim at steering the summation operator towards fainter contributions, we utilize this directional selection to coherently approximate the most dominant arrivals and subtract them from the data. Supported by additional filter functions which can be derived from wave front attributes gained during the stacking procedure, this strategy allows for a fully data-driven recovery of faint diffractions and makes them accessible for further processing. A complex single-channel field data example recorded in the Aegean sea near Santorini illustrates that the diffracted background wavefield is surprisingly rich and despite the absence of a high channel count can still be detected and characterized, suggesting a variety of applications in industry and academia.

  6. Idealized powder diffraction patterns for cellulose polymorphs

    Science.gov (United States)

    Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been determined with synchrotron X-radiation and neutron diffrac...

  7. Phase Transitions, Diffraction Studies and Marginal Dimensionality

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1985-01-01

    Continuous phase transitions and the associated critical phenomena have been one of the most active areas of research in condensed matter physics for several decades. This short review is only one cut through this huge subject and the author has chosen to emphasize diffraction studies as a basic...

  8. A Study of Simple Diffraction Models

    DEFF Research Database (Denmark)

    Agerkvist, Finn

    In this paper two simple methods for cabinet edge diffraction are examined. Calculations with both models are compared with more sophisticated theoretical models and with measured data. The parameters involved are studied and their importance for normal loudspeaker box designs is examined....

  9. Geometrical optics and the diffraction phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, Aleksandr V [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)

    2005-06-30

    This note outlines the principles of the geometrical optics of inhomogeneous waves whose description necessitates the use of complex values of the wave vector. Generalizing geometrical optics to inhomogeneous waves permits including in its scope the analysis of the diffraction phenomenon. (methodological notes)

  10. Diffraction and diffusion in room acoustics

    DEFF Research Database (Denmark)

    Rindel, Jens Holger; Rasmussen, Birgit

    1996-01-01

    that are not plane but curved or irregular. The importance of diffusion has been demonstrated in concert halls. Methods for the design of diffusing surfaces and the development of new types of diffusers are reviewed. Finally, the importance of diffraction and diffusion in room acoustic computer models is discussed....

  11. Development of Quantitative electron nano-diffraction

    NARCIS (Netherlands)

    Kumar, V.

    2009-01-01

    This thesis is a step towards development of quantitative parallel beam electron nano-diffraction (PBED). It is focused on the superstructure determination of zig-zag and zig-zig NaxCoO2 and analysis of charge distribution in the two polymorphs Nb12O29 using PBED. It has been shown that quantitative

  12. The Dynamical Theory of X Ray Diffraction

    Science.gov (United States)

    Balchin, A. A.; Whitehouse, C. R.

    1974-01-01

    Summarizes the Darwin theory of x-ray diffraction in thin crystals or crystals with a mosaic texture and its modified application to crystals with three-dimensional electrostatic dipoles. Indicates that the dynamical theory is brought into its present relevance by the improvement of single crystal growth techniques. (CC)

  13. Diffraction from nonperiodic models of cellulose crystals

    Science.gov (United States)

    Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose I' coordinates, and were subjected to various combinations of energy minimization and molecular dynamics (M...

  14. Concave diffraction gratings fabricated with planar lithography

    NARCIS (Netherlands)

    Grabarnik, S.; Emadi, A.; Wu, H.; De Graaf, G.; Wolffenbuttel, R.F.

    2008-01-01

    This paper reports on the development and validation of a new technology for the fabrication of variable line-spacing non-planar diffraction gratings to be used in compact spectrometers. The technique is based on the standard lithographic process commonly used for pattern transfer onto a flat substr

  15. Building X-ray Diffraction Calibration Software

    Energy Technology Data Exchange (ETDEWEB)

    Lande, Joshua; /Marlboro Coll.

    2007-10-31

    X-ray diffraction is a technique used to analyze the structure of crystals. It records the interference pattern created when x-rays travel through a crystal. Three dimensional structure can be inferred from these two dimensional diffraction patterns. Before the patterns can be analyzed, diffraction data must be precisely calibrated. Calibration is used to determine the experimental parameters of the particular experiment. This is done by fitting the experimental parameters to the diffraction pattern of a well understood crystal. Fit2D is a software package commonly used to do this calibration but it leaves much to be desired. In particular, it does not give very much control over the calibration of the data, requires a significant amount of manual input, does not allow for the calibration of highly tilted geometries, does not properly explain the assumptions that it is making, and cannot be modified. We build code to do this calibration while at the same time overcoming the limitations of Fit2D. This paper describes the development of the calibration software and the assumptions that are made in doing the calibration.

  16. A comment on the relation between diffraction and entropy

    CERN Document Server

    Baake, Michael

    2012-01-01

    Diffraction methods are used to detect atomic order in solids. While uniquely ergodic systems with pure point diffraction have zero entropy, the relation between diffraction and entropy is not as straightforward in general. In particular, there exist families of homometric systems, which are systems sharing the same diffraction, with varying entropy. We summarise the present state of understanding by several characteristic examples.

  17. Transmissive Diffractive Optical Element Solar Concentrators

    Science.gov (United States)

    Baron, Richard; Moynihan, Philip; Price, Douglas

    2008-01-01

    Solar-thermal-radiation concentrators in the form of transmissive diffractive optical elements (DOEs) have been proposed as alternatives to mirror-type solar concentrators now in use. In comparison with functionally equivalent mirror-type solar concentrators, the transmissive, diffractive solar concentrators would weigh and cost less, and would be subject to relaxed mechanical tolerances. A DOE concentrator would be made from a thin, flat disk or membrane of a transmissive material having a suitable index of refraction. By virtue of its thinness, the DOE concentrator would have an areal mass density significantly less than that of a functionally equivalent conventional mirror. The DOE concentrator would have a relatively wide aperture--characterized by a focal-length/aperture-diameter ratio ('f number') on the order of 1. A kinoform (a surface-relief phase hologram) of high diffractive order would be microfabricated onto one face of the disk. The kinoform (see figure) would be designed to both diffract and refract incident solar radiation onto a desired focal region, without concern for forming an image of the Sun. The high diffractive order of this kinoform (in contradistinction to the low diffractive orders of some other kinoforms) would be necessary to obtain the desired f number of 1, which, in turn, would be necessary for obtaining a desired concentration ratio of 2,500 or greater. The design process of optimizing the concentration ratio of a proposed DOE solar concentrator includes computing convolutions of the optical bandwidth of the Sun with the optical transmission of the diffractive medium. Because, as in the cases of other non-imaging, light-concentrating optics, image quality is not a design requirement, the process also includes trading image quality against concentration ratio. A baseline design for one example calls for an aperture diameter of 1 m. This baseline design would be scalable to a diameter as large as 10 m, or to a smaller diameter for a

  18. Nonlinear Optical Terahertz Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our approach is based on high-Q optical WGM resonators made with a nonlinear crystal. Such resonators have been demonstrated to dramatically enhance nonlinear...

  19. Phase retrieval using nonlinear diversity.

    Science.gov (United States)

    Lu, Chien-Hung; Barsi, Christopher; Williams, Matthew O; Kutz, J Nathan; Fleischer, Jason W

    2013-04-01

    We extend the Gerchberg-Saxton algorithm to phase retrieval in a nonlinear system. Using a tunable photorefractive crystal, we experimentally demonstrate the noninterferometric technique by reconstructing an unknown phase object from optical intensity measurements taken at different nonlinear strengths.

  20. Strong nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2017-01-01

    This book outlines an analytical solution procedure of the pure nonlinear oscillator system, offering a solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter. Includes exercises.

  1. Diffraction plane dependence of elastic constants in residual stress measurement by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Okido, Shinobu; Hayashi, Makoto [Hitachi Ltd., Tokyo (Japan); Morii, Yukio; Minakawa, Nobuaki; Tsuchiya, Yoshinori

    1997-06-01

    In a residual stress measurement by x-ray diffraction method and a neutron diffraction method, strictly speaking, the strain measurement of various diffracted surface was conducted and it is necessary to use its elastic modulus to convert from the strain to the stress. Then, in order to establish the residual stress measuring technique using neutron diffraction, it is an aim at first to make clear a diffraction surface dependency of elastic modulus for the stress conversion in various alloys. As a result of investigations the diffraction surface dependency of elastic module on SUS304 and STS410 steels by using RESA (Neutron diffractometer for residual stress analysis) installed at JRR-3M in Tokai Establishment of JAERI, following results are obtained. The elastic modulus of each diffraction surface considering till plastic region could be confirmed to be in a region of {+-}20% of that calculated by Kroner`s model and to be useful for that used on conversion to the stress. And, error of this elastic modulus was thought to cause the transition and defect formed at inner portion of the materials due to a plastic deformation. (G.K.)

  2. Nonlinear plasmonic resonances in graphene nanostructures

    Science.gov (United States)

    You, Jian Wei; Weismann, Martin; Panoiu, Nicolae C.

    2016-09-01

    Peculiar physical properties of graphene offer remarkable potential for advanced photonics, particularly in the area of nonlinear optics at deep-subwavelength scale. In this article, we use a theoretical and computational analysis to demonstrate an efficient mechanism for enhancing the third-harmonic generation in graphene diffraction gratings. By taking advantage of the relation between the resonance wavelength of localized surface-plasmon polaritons of graphene ribbons and disks their specific geometry, we can engineer the spectral response of graphene gratings so as strong plasmonic resonances exist at both the fundamental frequency and third-harmonic (TH). As a result of this dual resonance mechanism for optical near-field enhancement, the intensity of the TH can be increased greatly.

  3. Diffraction control in PT-symmetric photonic lattices: from beam rectification to dynamic localization

    CERN Document Server

    Kartashov, Yaroslav V; Konotop, Vladimir V; Torner, Lluis

    2016-01-01

    We address the propagation of light beams in longitudinally modulated PT-symmetric lattices, built as arrays of couplers with periodically varying separation between their channels, and show a number of possibilities for efficient diffraction control available in such non-conservative structures. The dynamics of light in such lattices crucially depends on the ratio of the switching length for the straight segments of each coupler and the longitudinal lattice period. Depending on the longitudinal period, one can achieve either beam rectification, when the input light propagates at a fixed angle across the structure without diffractive broadening, or dynamic localization, when the initial intensity distribution is periodically restored after each longitudinal period. Importantly, the transition between these two different propagation regimes can be achieved by tuning only gain and losses acting in the system, provided that the PT-symmetry remains unbroken. The impact of Kerr nonlinearity is also discussed.

  4. XUV coherent diffraction imaging in reflection geometry with low numerical aperture.

    Science.gov (United States)

    Zürch, Michael; Kern, Christian; Spielmann, Christian

    2013-09-09

    We present an experimental realization of coherent diffraction imaging in reflection geometry illuminating the sample with a laser driven high harmonic generation (HHG) based XUV source. After recording the diffraction pattern in reflection geometry, the data must be corrected before the image can be reconstructed with a hybrid-input-output (HIO) algorithm. In this paper we present a detailed investigation of sources of spoiling the reconstructed image due to the nonlinear momentum transfer, errors in estimating the angle of incidence on the sample, and distortions by placing the image off center in the computation grid. Finally we provide guidelines for the necessary parameters to realize a satisfactory reconstruction within a spatial resolution in the range of one micron for an imaging scheme with a numerical aperture NA < 0.03.

  5. Phase retrieval via regularization in self-diffraction based spectral interferometry

    CERN Document Server

    Birkholz, Simon; Koke, Sebastian; Gerth, Daniel; Bürger, Steven; Hofmann, Bernd

    2014-01-01

    A novel variant of spectral phase interferometry for direct electric-field reconstruction (SPIDER) is introduced and experimentally demonstrated. Other than most previously demonstrated variants of SPIDER, our method is based on a third-order nonlinear optical effect, namely self-diffraction, rather than the second-order effect of sum-frequency generation. On one hand, self-diffraction (SD) substantially simplifies phase-matching capabilities for multi-octave spectra that cannot be hosted by second-order processes, given manufacturing limitations of crystal lengths in the few-micrometer range. On the other hand, however, SD SPIDER imposes an additional constraint as it effectively measures the spectral phase of a self-convolved spectrum rather than immediately measuring the fundamental phase. Reconstruction of the latter from the measured phase and the spectral amplitude of the fundamental turns out to be an ill-posed problem, which we address by a regularization approach. We discuss the numerical implementat...

  6. Simplified optical image encryption approach using single diffraction pattern in diffractive-imaging-based scheme.

    Science.gov (United States)

    Qin, Yi; Gong, Qiong; Wang, Zhipeng

    2014-09-08

    In previous diffractive-imaging-based optical encryption schemes, it is impossible to totally retrieve the plaintext from a single diffraction pattern. In this paper, we proposed a new method to achieve this goal. The encryption procedure can be completed by proceeding only one exposure, and the single diffraction pattern is recorded as ciphertext. For recovering the plaintext, a novel median-filtering-based phase retrieval algorithm, including two iterative cycles, has been developed. This proposal not only extremely simplifies the encryption and decryption processes, but also facilitates the storage and transmission of the ciphertext, and its effectiveness and feasibility have been demonstrated by numerical simulations.

  7. Cubication of Conservative Nonlinear Oscillators

    Science.gov (United States)

    Belendez, Augusto; Alvarez, Mariela L.; Fernandez, Elena; Pascual, Immaculada

    2009-01-01

    A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear…

  8. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2013-01-01

    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...

  9. Fault Detection for Nonlinear Systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.H.

    1998-01-01

    The paper describes a general method for designing fault detection and isolation (FDI) systems for nonlinear processes. For a rich class of nonlinear systems, a nonlinear FDI system can be designed using convex optimization procedures. The proposed method is a natural extension of methods based...

  10. Influence of the higher-order nonlinearities in embodying the second-order holographic associative memories

    Science.gov (United States)

    Polyanskii, Peter V.; Felde, Christina V.; Konovchuk, Alexey V.; Oleksyuk, Maxim V.

    2015-11-01

    Recording nonlinearity is conventionally considered as the source of noise in holographic imaging. Important exclusion from this general statement is nonlinear holographic associative memory, where the quadratic recording nonlinearity causes true brightness rendering and the possibility for associative coupling and reconstructing optical signals of arbitrary complexity which are stored at the same carrier without interference. In this paper we discuss the role of nonlinearities of an amplitude response of a hologram of the orders higher than the quadratic one in implementing the second-ordered holographic associative memory. We show that higher-order nonlinearities are also involved in implementing this type of memory. This conclusion may be of importance for interpretation of biological/human memory also. The highlight of our study is the conclusion that reconstruction of the complex conjugate heteroassociative response is provided directly, viz. by the set of specified by us pseudogratings, rather than by the mechanism of sequential diffractions.

  11. Crystal growth of potassium 3,5-dinitrobenzoate (KDNB) for third order nonlinear optical (NLO) applications

    Science.gov (United States)

    Pandian, Muthu Senthil; Karuppasamy, P.; Ramasamy, P.

    2017-05-01

    The semi-organic nonlinear optical single crystals of potassium 3,5-dinitrobenzoate (KDNB) were grown by slow evaporation solution technique (SEST). The lattice parameters of the grown crystal were confirmed by single crystal X-ray diffraction analysis. The optical transmittance, cut-off wavelength and band gap of the KDNB crystal were obtained by UV-Vis NIR spectrum analysis. Vickers microhardness analysis was carried out to identify mechanical stability and work hardening co-efficient of the grown crystal. The crystalline perfection of the grown crystal was identified by chemical etching study using water as etchant. The third-order nonlinear optical properties such as nonlinear refractive index (n2), nonlinear absorption co-efficient (β) and third order nonlinear susceptibility (χ(3)) of KDNB crystal were evaluated using Z-scan technique at the wavelength of 632.8 nm.

  12. Self-focusing of femtosecond diffraction-resistant vortex beams in water.

    Science.gov (United States)

    Shiffler, Stacy; Polynkin, Pavel; Moloney, Jerome

    2011-10-01

    We report experiments on self-focusing of femtosecond diffraction-resistant vortex beams in water. These beams are higher-order Bessel beams with weak azimuthal modulation of the transverse intensity patterns. The modulation overrides the self-focusing dynamics and results in the formation of regular bottlelike filament distributions. The peak-power thresholds for filamentation, at a particular distance, are relatively accurately estimated by the adaptation of the Marburger formula derived earlier for Gaussian beams. The nonlinear conversion of the incident conical waves into the localized spatial wave packets propagating near the beam axis is observed.

  13. Interferometric backward third harmonic generation microscopy for axial imaging with accuracy beyond the diffraction limit.

    Directory of Open Access Journals (Sweden)

    Daaf Sandkuijl

    Full Text Available A new nonlinear microscopy technique based on interference of backward-reflected third harmonic generation (I-THG from multiple interfaces is presented. The technique is used to measure height variations or changes of a layer thickness with an accuracy of up to 5 nm. Height variations of a patterned glass surface and thickness variations of fibroblasts are visualized with the interferometric epi-THG microscope with an accuracy at least two orders of magnitude better than diffraction limit. The microscopy technique can be broadly applied for measuring distance variations between membranes or multilayer structures inside biological tissue and for surface height variation imaging.

  14. A Genetic Algorithm for Chromaticity Correction in Diffraction Limited Storage Rings

    CERN Document Server

    Ehrlichman, Michael

    2016-01-01

    An multi-objective genetic algorithm is developed for optimizing nonlinearities in diffraction limited storage rings. This algorithm determines sextupole and octupole strengths for chromaticity correction that deliver optimized dynamic aperture and beam lifetime. The algorithm makes use of dominance constraints to breed desirable properties into the early generations. The momentum aperture is optimized indirectly by constraining the chromatic tune footprint and optimizing the off-energy dynamic aperture. The result is an effective and computationally efficient technique for correcting chromaticity in a storage ring while maintaining optimal dynamic aperture and beam lifetime. This framework was developed for the Swiss Light Source (SLS) upgrade project.

  15. Transverse instabilities and pattern formation in two-beam-excited nonlinear optical interactions in liquids.

    Science.gov (United States)

    Bentley, Sean J; Heebner, John E; Boyd, Robert W

    2006-04-01

    We describe observations of various transverse instabilities that occur when two laser beams intersect in nonlinear optical liquids. Patterns that we observe include two types of conical emission and the generation of a linear array of spots. These results can be understood in terms of the physical processes of self-diffraction, two-beam-excited conical emission, and seeded modulational instability.

  16. Nonlinear electrostatic drift Kelvin-Helmholtz instability

    Science.gov (United States)

    Sharma, Avadhesh C.; Srivastava, Krishna M.

    1993-01-01

    Nonlinear analysis of electrostatic drift Kelvin-Helmholtz instability is performed. It is shown that the analysis leads to the propagation of the weakly nonlinear dispersive waves, and the nonlinear behavior is governed by the nonlinear Burger's equation.

  17. Two-Photon Ghost Image and Interference-Diffraction

    Science.gov (United States)

    Shih, Y. H.; Sergienko, A. V.; Pittman, T. B.; Strekalov, D. V.; Klyshko, D. N.

    1996-01-01

    One of the most surprising consequences of quantum mechanics is entanglement of two or more distance particles. The two-particle entangled state was mathematically formulated by Schrodinger. Based on this unusual quantum behavior, EPR defined their 'physical reality' and then asked the question: 'Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?' One may not appreciate EPR's criterion of physical reality and insist that 'no elementary quantum phenomenon is a phenomenon until it is a recorded phenomenon'. Optical spontaneous parametric down conversion (SPDC) is the most effective mechanism to generate an EPR type entangled two-photon state. In SPDC, an optical beam, called the pump, is incident on a birefringent crystal. The pump is intense enough so that nonlinear effects lead to the conversion of pump photons into pairs of photons, historically called signal and idler. Technically, the SPDC is said to be type-1 or type-2, depending on whether the signal and idler beams have parallel or orthogonal polarization. The SPDC conversion efficiency is typically on the order of 10(exp -9) to 10(exp -11), depending on the SPDC nonlinear material. The signal and idler intensities are extremely low, only single photon detection devices can register them. The quantum entanglement nature of SPDC has been demonstrated in EPR-Bohm experiments and Bell's inequality measurements. The following two experiments were recently performed in our laboratory, which are more closely related to the original 1935 EPR gedankenezperiment. The first experiment is a two-photon optical imaging type experiment, which has been named 'ghost image' by the physics community. The signal and idler beams of SPDC are sent in different directions, so that the detection of the signal and idler photons can be performed by two distant photon counting detectors. An aperture object (mask) is placed in front of the signal photon detector and illuminated by the signal beam through a

  18. Quantitative measurement of phase variation amplitude of ultrasonic diffraction grating based on diffraction spectral analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Meiyan, E-mail: yphantomohive@gmail.com; Zeng, Yingzhi; Huang, Zuohua, E-mail: zuohuah@163.com [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, Guangdong 510006 (China)

    2014-09-15

    A new method based on diffraction spectral analysis is proposed for the quantitative measurement of the phase variation amplitude of an ultrasonic diffraction grating. For a traveling wave, the phase variation amplitude of the grating depends on the intensity of the zeroth- and first-order diffraction waves. By contrast, for a standing wave, this amplitude depends on the intensity of the zeroth-, first-, and second-order diffraction waves. The proposed method is verified experimentally. The measured phase variation amplitude ranges from 0 to 2π, with a relative error of approximately 5%. A nearly linear relation exists between the phase variation amplitude and driving voltage. Our proposed method can also be applied to ordinary sinusoidal phase grating.

  19. Diffractive-imaging-based optical image encryption with simplified decryption from single diffraction pattern.

    Science.gov (United States)

    Qin, Yi; Wang, Zhipeng; Gong, Qiong

    2014-07-01

    In this paper, we propose a novel method for image encryption by employing the diffraction imaging technique. This method is in principle suitable for most diffractive-imaging-based optical encryption schemes, and a typical diffractive imaging architecture using three random phase masks in the Fresnel domain is taken for an example to illustrate it. The encryption process is rather simple because only a single diffraction intensity pattern is needed to be recorded, and the decryption procedure is also correspondingly simplified. To achieve this goal, redundant data are digitally appended to the primary image before a standard encrypting procedure. The redundant data serve as a partial input plane support constraint in a phase retrieval algorithm, which is employed for completely retrieving the plaintext. Simulation results are presented to verify the validity of the proposed approach.

  20. Phase knife-edge laser Schlieren diffraction interferometry with boundary diffraction wave theory

    Indian Academy of Sciences (India)

    Raj Kumar; D Mohan; Sushil K Kaura; D P Chhachhia; A K Aggarwal

    2007-04-01

    Within the framework of boundary diffraction wave theory it has been shown that the first bright fringe on either side of the central dark fringe of the phase knife-edge Fresnel diffraction pattern could be broadened to cover the whole field of view. Broadening of the first diffraction fringe, instead of conventionally modifying the spatial frequency spectrum, enhances the sensitivity of the Schlieren system. The use of phase knife-edge as viewing diaphragm in Schlieren diffraction interferometry not only enhances the fringe contrast but also avoids the loss in phase information as it lets through light from all parts of the test object and its thin interfacing makes the method suitable even for studying weak disturbances.

  1. Optothermal nonlinearity of silica aerogel

    CERN Document Server

    Braidotti, Maria Chiara; Fleming, Adam; Samuels, Michiel C; Di Falco, Andrea; Conti, Claudio

    2016-01-01

    We report on the characterization of silica aerogel thermal optical nonlinearity, obtained by z-scan technique. The results show that typical silica aerogels have nonlinear optical coefficient similar to that of glass $(\\simeq 10^{-12} $m$^2/$W), with negligible optical nonlinear absorption. The non\\-li\\-near coefficient can be increased to values in the range of $10^{-10} $m$^2/$W by embedding an absorbing dye in the aerogel. This value is one order of magnitude higher than that observed in the pure dye and in typical highly nonlinear materials like liquid crystals.

  2. Essentials of nonlinear optics

    CERN Document Server

    Murti, Y V G S

    2014-01-01

    Current literature on Nonlinear Optics varies widely in terms of content, style, and coverage of specific topics, relative emphasis of areas and the depth of treatment. While most of these books are excellent resources for the researchers, there is a strong need for books appropriate for presenting the subject at the undergraduate or postgraduate levels in Universities. The need for such a book to serve as a textbook at the level of the bachelors and masters courses was felt by the authors while teaching courses on nonlinear optics to students of both science and engineering during the past two decades. This book has emerged from an attempt to address the requirement of presenting the subject at college level. A one-semester course covering the essentials can effectively be designed based on this.

  3. Nonlinear metamaterials for holography

    Science.gov (United States)

    Almeida, Euclides; Bitton, Ora; Prior, Yehiam

    2016-08-01

    A hologram is an optical element storing phase and possibly amplitude information enabling the reconstruction of a three-dimensional image of an object by illumination and scattering of a coherent beam of light, and the image is generated at the same wavelength as the input laser beam. In recent years, it was shown that information can be stored in nanometric antennas giving rise to ultrathin components. Here we demonstrate nonlinear multilayer metamaterial holograms. A background free image is formed at a new frequency--the third harmonic of the illuminating beam. Using e-beam lithography of multilayer plasmonic nanoantennas, we fabricate polarization-sensitive nonlinear elements such as blazed gratings, lenses and other computer-generated holograms. These holograms are analysed and prospects for future device applications are discussed.

  4. Nonlinear metamaterials for holography

    Science.gov (United States)

    Almeida, Euclides; Bitton, Ora

    2016-01-01

    A hologram is an optical element storing phase and possibly amplitude information enabling the reconstruction of a three-dimensional image of an object by illumination and scattering of a coherent beam of light, and the image is generated at the same wavelength as the input laser beam. In recent years, it was shown that information can be stored in nanometric antennas giving rise to ultrathin components. Here we demonstrate nonlinear multilayer metamaterial holograms. A background free image is formed at a new frequency—the third harmonic of the illuminating beam. Using e-beam lithography of multilayer plasmonic nanoantennas, we fabricate polarization-sensitive nonlinear elements such as blazed gratings, lenses and other computer-generated holograms. These holograms are analysed and prospects for future device applications are discussed. PMID:27545581

  5. Nonlinear data assimilation

    CERN Document Server

    Van Leeuwen, Peter Jan; Reich, Sebastian

    2015-01-01

    This book contains two review articles on nonlinear data assimilation that deal with closely related topics but were written and can be read independently. Both contributions focus on so-called particle filters. The first contribution by Jan van Leeuwen focuses on the potential of proposal densities. It discusses the issues with present-day particle filters and explorers new ideas for proposal densities to solve them, converging to particle filters that work well in systems of any dimension, closing the contribution with a high-dimensional example. The second contribution by Cheng and Reich discusses a unified framework for ensemble-transform particle filters. This allows one to bridge successful ensemble Kalman filters with fully nonlinear particle filters, and allows a proper introduction of localization in particle filters, which has been lacking up to now.

  6. Nonlinearity without Superluminality

    CERN Document Server

    Kent, A

    2002-01-01

    Quantum theory is compatible with special relativity. In particular, though measurements on entangled systems are correlated in a way that cannot be reproduced by local hidden variables, they cannot be used for superluminal signalling. As Gisin and Polchinski first pointed out, this is not true for general nonlinear modifications of the Schroedinger equation. Excluding superluminal signalling has thus been taken to rule out most nonlinear versions of quantum theory. The no superluminal signalling constraint has also been used for alternative derivations of the optimal fidelities attainable for imperfect quantum cloning and other operations. These results apply to theories satisfying the rule that their predictions for widely separated and slowly moving entangled systems can be approximated by non-relativistic equations of motion with respect to a preferred time coordinate. This paper describes a natural way in which this rule might fail to hold. In particular, it is shown that quantum readout devices which di...

  7. Monte Carlo and nonlinearities

    CERN Document Server

    Dauchet, Jérémi; Blanco, Stéphane; Caliot, Cyril; Charon, Julien; Coustet, Christophe; Hafi, Mouna El; Eymet, Vincent; Farges, Olivier; Forest, Vincent; Fournier, Richard; Galtier, Mathieu; Gautrais, Jacques; Khuong, Anaïs; Pelissier, Lionel; Piaud, Benjamin; Roger, Maxime; Terrée, Guillaume; Weitz, Sebastian

    2016-01-01

    The Monte Carlo method is widely used to numerically predict systems behaviour. However, its powerful incremental design assumes a strong premise which has severely limited application so far: the estimation process must combine linearly over dimensions. Here we show that this premise can be alleviated by projecting nonlinearities on a polynomial basis and increasing the configuration-space dimension. Considering phytoplankton growth in light-limited environments, radiative transfer in planetary atmospheres, electromagnetic scattering by particles and concentrated-solar-power-plant productions, we prove the real world usability of this advance on four test-cases that were so far regarded as impracticable by Monte Carlo approaches. We also illustrate an outstanding feature of our method when applied to sharp problems with interacting particles: handling rare events is now straightforward. Overall, our extension preserves the features that made the method popular: addressing nonlinearities does not compromise o...

  8. Nonlinear Photonics 2014: introduction.

    Science.gov (United States)

    Akhmediev, N; Kartashov, Yaroslav

    2015-01-12

    International Conference "Nonlinear Photonics-2014" took place in Barcelona, Spain on July 27-31, 2014. It was a part of the "Advanced Photonics Congress" which is becoming a traditional notable event in the world of photonics. The current focus issue of Optics Express contains contributions from the participants of the Conference and the Congress. The articles in this focus issue by no means represent the total number of the congress contributions (around 400). However, it demonstrates wide range of topics covered at the event. The next conference of this series is to be held in 2016 in Australia, which is the home of many researchers working in the field of photonics in general and nonlinear photonics in particular.

  9. Diffraction of limit periodic point sets

    CERN Document Server

    Baake, Michael

    2010-01-01

    Limit periodic point sets are aperiodic structures with pure point diffraction supported on a countably, but not finitely generated Fourier module that is based on a lattice and certain integer multiples of it. Examples are cut and project sets with p-adic internal spaces. We illustrate this by explicit results for the diffraction measures of two examples with 2-adic internal spaces. The first and well-known example is the period doubling sequence in one dimension, which is based on the period doubling substitution rule. The second example is a weighted planar point set that is derived from the classic chair tiling in the plane. It can be described as a fixed point of a block substitution rule.

  10. Diffractive and Exclusive Measurements at CMS

    CERN Document Server

    Ruspa, Marta

    2014-01-01

    Recent measurements are discussed of inclusive and exclusive diffractive processes in pp colli- sions at √ s = 7 TeV at the LHC using the CMS detector. Results are presented of the single- and double-diffractive cross section and of the inclusive differential cross section for events with a forward rapidity gap. A study of exclusive W + W − production by two-photon exchange, where, in different kinematic regions, both con fi rmation and deviations from the Standard Model predic- tions are searched, is reported. Finally, a joint measurement with the CMS and TOTEM detectors of the pseudorapidity distribution of charged particles produced in pp collisions at √ s = 8 TeV is presented. This is the fi rst joint study between the two experiments.

  11. Laser diffraction analysis of colloidal crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sogami, Ikuo S.; Shinohara, Tadatomi; Yoshiyama, Tsuyoshi [Kyoto Sangyo Univ., Department of Physics, Kyoto (Japan)

    2001-10-01

    Laser diffraction analysis is made on crystallization in salt-free aqueous suspensions of highly-charged colloidal particles for semi-dilute specimens of concentration 0.1-10.0 vol%. Kossel diffraction patterns which represent faithfully accurate information on lattice symmetries in the suspensions enable us to investigate the time evolution of colloidal crystals. The results show that the crystallization proceeds by way of the following intermediate phase transitions: two-dimensional hcp structure {yields} random layer structure {yields} layer structure with one sliding degree of freedom {yields} stacking disorder structure {yields} stacking structure with multivariant periodicity {yields} fcc twin structure with twin plane (111) {yields} normal fcc structure {yields} bcc twin structure with twin plane (11-bar2) or (1-bar12) {yields} normal bcc structure. For concentrated suspensions (>2 vol %), the phase transition ceases to proceed at the normal fcc structure. (author)

  12. Diffractive and exclusive measurements at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Gallinaro, Michele; /Rockefeller U.

    2006-06-01

    Experimental results from the CDF experiment at the Tevatron in p{bar p} collisions at {radical}s = 1.96 TeV are presented on the diffractive structure function at different values of the exchanged momentum transfer squared in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, on the four-momentum transfer |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}, and on the first experimental evidence of exclusive production in both dijet and diphoton events. A novel technique to align the Roman Pot detectors is also presented.

  13. Hard diffraction in the QCD dipole picture

    CERN Document Server

    Bialas, A

    1995-01-01

    Using the QCD dipole picture of the BFKL pomeron, the gluon contribution to the cross-section for single diffractive dissociation in deep-inelastic high-energy scattering is calculated. The resulting contribution to the proton diffractive structure function integrated over t is given in terms of relevant variables, x_{\\cal P}, Q^2, and \\beta = x_{Bj}/x_{\\cal P}. It factorizes into an explicit x_{\\cal P}-dependent Hard Pomeron flux factor and structure function. The flux factor is found to have substantial logarithmic corrections which may account for the recent measurements of the Pomeron intercept in this process. The triple Pomeron coupling is shown to be strongly enhanced by the resummation of leading logs. The obtained pattern of scaling violation at small \\beta is similar to that for F_2 at small x_{Bj}.

  14. Periodically distributed objects with quasicrystalline diffraction pattern

    Energy Technology Data Exchange (ETDEWEB)

    Wolny, Janusz, E-mail: wolny@fis.agh.edu.pl; Strzalka, Radoslaw [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Kuczera, Pawel [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Laboratory of Crystallography, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich (Switzerland)

    2015-03-30

    It is possible to construct fully periodically distributed objects with a diffraction pattern identical to the one obtained for quasicrystals. These objects are probability distributions of distances obtained in the statistical approach to aperiodic structures distributed periodically. The diffraction patterns have been derived by using a two-mode Fourier transform—a very powerful method not used in classical crystallography. It is shown that if scaling is present in the structure, this two-mode Fourier transform can be reduced to a regular Fourier transform with appropriately rescaled scattering vectors and added phases. Detailed case studies for model sets 1D Fibonacci chain and 2D Penrose tiling are discussed. Finally, it is shown that crystalline, quasicrystalline, and approximant structures can be treated in the same way.

  15. Resonant diffraction of synchrotron radiation: New possibilities

    Science.gov (United States)

    Ovchinnikova, E. N.; Mukhamedzhanov, E. Kh.

    2016-09-01

    Resonant diffraction of synchrotron radiation (SR) is a modern method of studying the structure and properties of condensed matter that can be implemented on third-generation synchrotrons. This method allows one to investigate local properties of media (including magnetic and electronic ones) and observe thermal vibrations, defects, and orbital and charge orderings. A brief review of the advance provided by SR resonant diffraction is presented, and the capabilities of this method for analyzing phase transitions are considered in more detail by the example of potassium dihydrogen phosphate and rubidium dihydrogen phosphate crystals. It is shown that the investigation of the temperature dependence of forbidden reflections not only makes it possible to observe the transition from para- to ferroelectric phase, but also gives information about the proton distribution at hydrogen bonds.

  16. Ray-Based Reflectance Model for Diffraction

    CERN Document Server

    Cuypers, Tom; Haber, Tom; Bekaert, Philippe; Raskar, Ramesh

    2011-01-01

    We present a novel method of simulating wave effects in graphics using ray--based renderers with a new function: the Wave BSDF (Bidirectional Scattering Distribution Function). Reflections from neighboring surface patches represented by local BSDFs are mutually independent. However, in many surfaces with wavelength-scale microstructures, interference and diffraction requires a joint analysis of reflected wavefronts from neighboring patches. We demonstrate a simple method to compute the BSDF for the entire microstructure, which can be used independently for each patch. This allows us to use traditional ray--based rendering pipelines to synthesize wave effects of light and sound. We exploit the Wigner Distribution Function (WDF) to create transmissive, reflective, and emissive BSDFs for various diffraction phenomena in a physically accurate way. In contrast to previous methods for computing interference, we circumvent the need to explicitly keep track of the phase of the wave by using BSDFs that include positiv...

  17. Photoelectron diffraction and holography: Some new directions

    Energy Technology Data Exchange (ETDEWEB)

    Fadley, C.S. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Davis, CA (United States). Dept. of Physics

    1993-08-01

    Photoelectron diffraction has by now become a versatile and powerful technique for studying surface structures, with special capabilities for resolving chemical and magnetic states of atoms and deriving direct structural information from both forward scattering along bond directions and back-scattering path length differences. Further fitting experiment to theory can lead to structural accuracies in the {plus_minus}0.03 ){Angstrom} range. Holographic inversions of such diffraction data also show considerable promise for deriving local three-dimensional structures around a given emitter with accuracies of {plus_minus}0.2--0.3 {Angstrom}. Resolving the photoelectron spin in some way and using circularly polarized radiation for excitation provide added dimensions for the study of magnetic systems and chiral experimental geometries. Synchrotron radiation with the highest brightness and energy resolution, as well as variable polarization, is crucial to the full exploitation of these techniques.

  18. X-ray diffraction with novel geometry

    Energy Technology Data Exchange (ETDEWEB)

    Prokopiou, Danae [Department of Engineering and Applied Science Cranfield University, Shrivenham Campus, Swindon (United Kingdom); Rogers, Keith, E-mail: k.d.rogers@cranfield.ac.uk [Department of Engineering and Applied Science Cranfield University, Shrivenham Campus, Swindon (United Kingdom); Evans, Paul; Godber, Simon [Imaging Science Group, School of Science and Technology, Nottingham Trent University Clifton Campus, Nottingham (United Kingdom); Shackel, James [Department of Engineering and Applied Science Cranfield University, Shrivenham Campus, Swindon (United Kingdom); Dicken, Anthony [Imaging Science Group, School of Science and Technology, Nottingham Trent University Clifton Campus, Nottingham (United Kingdom)

    2014-01-21

    An innovative geometry for high efficiency harvesting of diffracted X-rays is explored. Further to previous work where planar samples were fixed normal to the primary axis, this work extends focal construct geometry (FCG), to samples randomly oriented with respect to the incident beam. The effect of independent sample rotation around two axes upon the scattering distributions was investigated in analytical, simulation and empirical manners. It was found that, although the profile of Bragg maxima were modified when the sample was rotated, high intensity diffraction data was still acquired. Modelling produced a good match to the empirical data and it was shown that the distortions caused by sample rotation were not severe and predictable even when sample rotations were large. The implications for this are discussed.

  19. Neutron diffraction of cell membranes (myelin).

    Science.gov (United States)

    Parsons, D F; Akers, C K

    1969-09-05

    Small-angle neutron diffraction (wavelength 4.05 angstroms) of human and rabbit sciatic nerve has been carried out by means of the Brookhaven high flux beam reactor with an automated slit camera. Most of the free water of the nerves was substituted in order to minimize incoherent scatter of hydrogen atoms. The differences in amplitude and phase shifts between neutrons and x-rays resulted in a neutron diffraction pattern that was completely different from the x-ray pattern. The neutron pattern consisted of a single peak of about 89-angstrom spacing in the region examined (up to 6-angstrom spacing). The strong third, fourth, and fifth order reflections (about 60, 45, and 36 angstroms) seen in the x-ray pattern were suppressed. The neutron data indicated a strong scattering from one portion of the membrane.

  20. When holography meets coherent diffraction imaging

    CERN Document Server

    Latychevskaia, Tatiana; Fink, Hans-Werner

    2011-01-01

    In understanding the physical, chemical and biological properties of a molecule by obtaining detailed information about its structure, there is an ultimate wish: the visualization of this very molecule in three dimensions at atomic scale, rather than obtaining structural information by averaging over an ensemble of molecules. Coherent diffraction imaging (CDI) is a modern lens-less imaging technique promising exactly that: visualizing an individual molecule at the highest possible resolution solely limited by the radiation wavelength. Individual bacteria and viruses have been imaged by CDI employing coherent X-rays and recently, CDI has been extended to recover the three-dimensional shape of objects from a single diffraction pattern. Higher resolution is expected with the implementation of bright coherent radiation from X-ray free electron lasers. Since detectors are only sensitive to intensity, the phase of the wave is missing and must somehow be recovered to reconstruct the molecule's anatomy. There are two...

  1. Nonlinear fractional relaxation

    Indian Academy of Sciences (India)

    A Tofighi

    2012-04-01

    We define a nonlinear model for fractional relaxation phenomena. We use -expansion method to analyse this model. By studying the fundamental solutions of this model we find that when → 0 the model exhibits a fast decay rate and when → ∞ the model exhibits a power-law decay. By analysing the frequency response we find a logarithmic enhancement for the relative ratio of susceptibility.

  2. -Deformed nonlinear maps

    Indian Academy of Sciences (India)

    Ramaswamy Jaganathan; Sudeshna Sinha

    2005-03-01

    Motivated by studies on -deformed physical systems related to quantum group structures, and by the elements of Tsallis statistical mechanics, the concept of -deformed nonlinear maps is introduced. As a specific example, a -deformation procedure is applied to the logistic map. Compared to the canonical logistic map, the resulting family of -logistic maps is shown to have a wider spectrum of interesting behaviours, including the co-existence of attractors – a phenomenon rare in one-dimensional maps.

  3. Controllability of nonlinear systems.

    Science.gov (United States)

    Sussmann, H. J.; Jurdjevic, V.

    1972-01-01

    Discussion of the controllability of nonlinear systems described by the equation dx/dt - F(x,u). Concepts formulated by Chow (1939) and Lobry (1970) are applied to establish criteria for F and its derivatives to obtain qualitative information on sets which can be obtained from x which denotes a variable of state in an arbitrary, real, analytical manifold. It is shown that controllability implies strong accessibility for a large class of manifolds including Euclidean spaces.-

  4. Stochastic Nonlinear Aeroelasticity

    Science.gov (United States)

    2009-01-01

    STOCHASTIC NONLINEAR AEROELASTICITY 5a. CONTRACT NUMBER In- house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 0601102 6. AUTHOR(S) Philip S...ABSTRACT This report documents the culmination of in- house work in the area of uncertainty quantification and probabilistic techniques for... coff U∞ cs ea lw cw Figure 6: Wing and store geometry (left), wing box structural model (middle), flutter distribution (right

  5. Nonlinear Control Systems

    Science.gov (United States)

    2007-03-01

    IEEE Transactions on Automatic Control , AC- 48, pp. 1712-1723, (2003). [14] C.I. Byrnes, A. Isidori...Nonlinear internal models for output regulation,” IEEE Transactions on Automatic Control , AC-49, pp. 2244-2247, (2004). [15] C.I. Byrnes, F. Celani, A...approach,” IEEE Transactions on Automatic Control , 48 (Dec. 2003), 2172–2190. 2. C. I. Byrnes, “Differential Forms and Dynamical Systems,” to appear

  6. Filamentation with nonlinear Bessel vortices.

    Science.gov (United States)

    Jukna, V; Milián, C; Xie, C; Itina, T; Dudley, J; Courvoisier, F; Couairon, A

    2014-10-20

    We present a new type of ring-shaped filaments featured by stationary nonlinear high-order Bessel solutions to the laser beam propagation equation. Two different regimes are identified by direct numerical simulations of the nonlinear propagation of axicon focused Gaussian beams carrying helicity in a Kerr medium with multiphoton absorption: the stable nonlinear propagation regime corresponds to a slow beam reshaping into one of the stationary nonlinear high-order Bessel solutions, called nonlinear Bessel vortices. The region of existence of nonlinear Bessel vortices is found semi-analytically. The influence of the Kerr nonlinearity and nonlinear losses on the beam shape is presented. Direct numerical simulations highlight the role of attractors played by nonlinear Bessel vortices in the stable propagation regime. Large input powers or small cone angles lead to the unstable propagation regime where nonlinear Bessel vortices break up into an helical multiple filament pattern or a more irregular structure. Nonlinear Bessel vortices are shown to be sufficiently intense to generate a ring-shaped filamentary ionized channel in the medium which is foreseen as opening the way to novel applications in laser material processing of transparent dielectrics.

  7. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  8. Neutron forward diffraction by single crystal prisms

    Indian Academy of Sciences (India)

    Sohrab Abbas; Apoorva G Wagh; Markus Strobl; Wolfgang Treimer

    2008-11-01

    We have derived analytic expressions for the deflection as well as transmitted fraction of monochromatic neutrons forward diffracted by a single crystal prism. In the vicinity of a Bragg reflection, the neutron deflection deviates sharply from that for an amorphous prism, exhibiting three orders of magnitude greater sensitivity to the incidence angle. We have measured the variation of neutron deflection and transmission across a Bragg reflection, for several single crystal prisms. The results agree well with theory.

  9. Multidataset Refinement Resonant Diffraction, and Magnetic Structures

    OpenAIRE

    Attfield, J. Paul

    2004-01-01

    The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset refinement is now commonplace; the datasets may be from different detectors, e.g., in a time-of-flight experiment, or from separate experiments, such as at several x-ray energies giving resonant information. The complementary use of x rays and neutrons is exe...

  10. Basic of X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Giacovazzo, C. [Bari Univ. (Italy). Dip. Geomineralogico

    1996-09-01

    The basic concepts of X-ray diffraction may be more easily understood if it is made preliminary use of a mathematical background. In these pages the authors will first define the delta function and its use for the representation of a lattice. Then the concepts of Fourier transform and convolution are given. At the end of this talk one should realize that a crystal is the convolution of the lattice with a function representing the content of the unit cell.

  11. ATLAS results on diffraction and exclusive production

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00224260; The ATLAS collaboration

    2017-01-01

    Various aspects of forward physics have been studied by the ATLAS collaboration using data from Run I at the LHC. In this text, main results of three published analyses are summarized, based on data from proton-proton collisions at $\\sqrt{s} = 7$ or 8 TeV collected between 2010 and 2012. One analysis deals with diffractive signature with at least two jets in the final state, the other two study exclusive production of a pair of leptons or W bosons.

  12. Theoretical and measured performance of diffraction gratings

    Energy Technology Data Exchange (ETDEWEB)

    Bowler, M.A. E-mail: m.bowler@dl.ac.uk; Finetti, P.; Holland, D.M.P.; Humphrey, I.; Quinn, F.M.; Roper, M.D

    2001-07-21

    At the SRS at Daresbury Laboratory, we are undertaking a programme comparing the results from efficiency calculations of diffraction gratings, mainly using the GRADIF code of Neviere, with measured efficiencies. The deviations from the predicted performance are larger for higher orders than for first order. Higher order contamination is important in determining the usability of the beamline for certain types of experiments, particularly at energies below 100 eV.

  13. Theoretical and measured performance of diffraction gratings

    CERN Document Server

    Bowler, M A; Holland, D M P; Humphrey, I; Quinn, F M; Röper, M D

    2001-01-01

    At the SRS at Daresbury Laboratory, we are undertaking a programme comparing the results from efficiency calculations of diffraction gratings, mainly using the GRADIF code of Neviere, with measured efficiencies. The deviations from the predicted performance are larger for higher orders than for first order. Higher order contamination is important in determining the usability of the beamline for certain types of experiments, particularly at energies below 100 eV.

  14. Diffraction method of vocal chord oscillation sensing

    Science.gov (United States)

    Kuzmin, Sergey Y.; Tuchin, Valery V.

    1996-04-01

    A method of small-amplitude biovibrations detection is presented in the paper. The method uses a dependence of properties of speckle-structures formed by focused coherent light field diffraction from rough surfaces on the statistics and movement parameters of the surface. With the help of computer modeling the different components of skin surface vibration were analyzed and their influence on speckles dynamics was studied. Human vocal chord oscillations spectrum was monitored using the developed technique.

  15. Diffraction studies of papaya mosaic virus.

    Science.gov (United States)

    Tollin, P; Bancroft, J B; Richardson, J F; Payne, N C; Beveridge, T J

    1979-10-15

    X-ray and optical diffraction studies of the flexuous papaya mosaic virus are described. The virus is constructed so that there are 35 coat protein subunits in 4 turns of the helix. The virus contains about 1410 protein subunits and 6800 nucleotides and has a molecular weight of about 33 x 10(6). The structure of tubes assembled in vitro from coat protein both in the presence and absence of nucleic acid resembles that of the native virus.

  16. New Forward and Diffractive Physics at CMS

    Science.gov (United States)

    Santoro, Alberto

    2011-04-01

    Forward and Diffractive Physics (FWP) in LHC is a new open window to understand this type of strong interactions. We will present a didactic description of the topics being developed at CMS. As we know there still is no new results to present for FWP. We are accumulating data to have soon new results. We will show a number of topics and the detectors properties to do the observation of several topologies. We expect to give an optimistic view of the area.

  17. Optimizing Crystal Volume for Neutron Diffraction Studies

    Science.gov (United States)

    Snell, E. H.

    2003-01-01

    For structural studies with neutron diffraction more intense neutron sources, improved sensitivity detector and larger volume crystals are all means by which the science is being advanced to enable studies on a wider range of samples. We have chosen a simplistic approach using a well understood crystallization method, with minimal amounts of sample and using design of experiment techniques to maximize the crystal volume all for minimum effort. Examples of the application are given.

  18. Metamaterial hyperlens demonstration of propagation without diffraction

    Science.gov (United States)

    Fleming, Simon

    2017-03-01

    Metamaterials are a topic of much research interest because they have such extraordinary properties. Such materials are generally difficult and expensive to make and to characterize, and thus beyond the reach of undergraduate classes. This paper describes a metamaterial hyperlens, fabricated in about an hour from materials costing about one dollar, which permits an experimental demonstration of propagation without diffraction using common undergraduate laboratory microwave equipment.

  19. Diffraction Measurements on CPF Steel Fatigue Samples

    Science.gov (United States)

    1995-05-30

    I I I I I I I I I I I I I I I I I I I - 535 - Diffraction Measurements on CPF Steel Fatigue Samples by Percy Clark*, Tom...to the formation of a detectable fatigue crack, a series of hourglass shaped specimens were fabricated from 350WT steel , cyclically loaded to...were made between these experiments and earlier less successful similar experiments conducted on HY80 samples. The limitations and potential for the

  20. Wave envelopes method for description of nonlinear acoustic wave propagation.

    Science.gov (United States)

    Wójcik, J; Nowicki, A; Lewin, P A; Bloomfield, P E; Kujawska, T; Filipczyński, L

    2006-07-01

    A novel, free from paraxial approximation and computationally efficient numerical algorithm capable of predicting 4D acoustic fields in lossy and nonlinear media from arbitrary shaped sources (relevant to probes used in medical ultrasonic imaging and therapeutic systems) is described. The new WE (wave envelopes) approach to nonlinear propagation modeling is based on the solution of the second order nonlinear differential wave equation reported in [J. Wójcik, J. Acoust. Soc. Am. 104 (1998) 2654-2663; V.P. Kuznetsov, Akust. Zh. 16 (1970) 548-553]. An incremental stepping scheme allows for forward wave propagation. The operator-splitting method accounts independently for the effects of full diffraction, absorption and nonlinear interactions of harmonics. The WE method represents the propagating pulsed acoustic wave as a superposition of wavelet-like sinusoidal pulses with carrier frequencies being the harmonics of the boundary tone burst disturbance. The model is valid for lossy media, arbitrarily shaped plane and focused sources, accounts for the effects of diffraction and can be applied to continuous as well as to pulsed waves. Depending on the source geometry, level of nonlinearity and frequency bandwidth, in comparison with the conventional approach the Time-Averaged Wave Envelopes (TAWE) method shortens computational time of the full 4D nonlinear field calculation by at least an order of magnitude; thus, predictions of nonlinear beam propagation from complex sources (such as phased arrays) can be available within 30-60 min using only a standard PC. The approximate ratio between the computational time costs obtained by using the TAWE method and the conventional approach in calculations of the nonlinear interactions is proportional to 1/N2, and in memory consumption to 1/N where N is the average bandwidth of the individual wavelets. Numerical computations comparing the spatial field distributions obtained by using both the TAWE method and the conventional approach

  1. Non-diffractive beam in random media

    Science.gov (United States)

    Shiina, Tatsuo

    2017-09-01

    Beam propagation has been given important attention in a variety of applications in medicine, remote sensing and information science. Especially, the beam propagation in highly scattering media, which is called random media, is important. In general, the multiple scattering gets rid of beam characteristics, e.g., intensity distribution, phase front, and polarization. In this study, self-converging effect of annular beam was applied in random media. Diluted milk was used as random media, and the transmitted light was detected with a narrow view angle of 5.5mrad. The collimated annular beam of a few tens millimeters takes a few hundred meters to transform its beam shape into the non-diffractive beam in free space, while this transformation was shorten only to 20 cm in random media, that is, the collimated annular beam caused its transformation at only 20 cm in random media. The transformed beam kept its optical characteristics of ;non-diffractive beam;. Such transformation of the annular beam needs the appropriate condition of random media. Media concentration and propagation distance control the generation of the center peak intensity of the transformed beam. This study indicates the generation of the non-diffractive beam in random media and reveals its appropriate condition.

  2. New approaches in diffraction based optical metrology

    Science.gov (United States)

    Ebert, M.; Vanoppen, P.; Jak, M.; v. d. Zouw, G.; Cramer, H.; Nooitgedagt, T.; v. d. Laan, H.

    2016-03-01

    Requirements for on-product overlay, focus and CD uniformity continue to tighten in order to support the demands of 10nm and 7nm nodes. This results in the need for simultaneously accurate, robust and dense metrology data as input for closed-loop control solutions thereby enabling wafer-level control and high order corrections. In addition the use of opaque materials and stringent design rules drive the need for expansion of the available measurement wavelengths and metrology target design space. Diffraction based optical metrology has been established as the leading methodology for integrated as well as standalone optical metrology for overlay, focus and CD monitoring and control in state of the art chip manufacturing. We are presenting the new approaches to diffraction based optical metrology designed to meet the processing diffraction based metrology signals. In this paper we will present the new detection principle and its impact on key performance characteristics of overlay and focus measurements. We will also describe the wide range of applications of a newly introduced increased measurement spot size, enabling significant improvements to accuracy and process robustness of overlay and focus measurements. With the YS350E the optical CD measurement capability is also extended, to 10x10μm2 targets. We will discuss the performance and value of small targets in after-develop and after-etch applications.

  3. Enhanced analysis of biomaterials by synchrotron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, K. [Cranfield Postgraduate Medical School, Cranfield University, Shrivenham, Swindon, Wiltshire, SN6 8LA (United Kingdom)]. E-mail: k.d.rogers@cranfield.ac.uk; Etok, S. [Cranfield Postgraduate Medical School, Cranfield University, Shrivenham, Swindon, Wiltshire, SN6 8LA (United Kingdom); Broadhurst, A. [Cranfield Postgraduate Medical School, Cranfield University, Shrivenham, Swindon, Wiltshire, SN6 8LA (United Kingdom); Scott, R. [Biomet-Europe, Dorcan Way, Swindon, Wiltshire, SN3 5HY (United Kingdom)

    2005-08-11

    There is an increasing body of evidence that prosthetic implants based upon titanium alloys attain improved performance when coated with calcium hydroxyapatite (HAP). Such coatings appear to promote osteointegration and bone in-growth. Plasma spraying is the most frequently employed route to coating fabrication. Detailed chemical and structural characterisation of these coatings is essential for (i) coating technology development (ii) ensuring consistent material quality and (iii) assessing coating performance. The work presented here employed combined conventional powder diffraction and glancing angle synchrotron diffraction to examine the in vitro performance of apatite coatings formed by plasma spraying. Coatings were exposed to simulated body fluid and foetal calf serum, and changes to the coating chemistry and structure determined. A new analysis method, synchrotron depth profiling tomography, has been applied to obtain structural features through the coating depth. The dissolution and re-precipitation behaviour of the coatings was found to be significantly different for each media. For the first time, it has been possible to identify and quantify the formation of a nanocrystalline, carbonated HAP phase. It has been possible to simultaneously model all coating phases apparent within the X-ray diffraction data and thus quantify changes to film composition. DPT has also revealed subtle changes in coating features with depth and these may have a significant impact on coating dissolution. The findings are discussed in the context of kinematic models for the coating behaviour and implications for the performance of such coatings in vivo.

  4. Shock Wave Diffraction Phenomena around Slotted Splitters

    Directory of Open Access Journals (Sweden)

    Francesca Gnani

    2015-01-01

    Full Text Available In the field of aerospace engineering, the study of the characteristics of vortical flows and their unsteady phenomena finds numerous engineering applications related to improvements in the design of tip devices, enhancement of combustor performance, and control of noise generation. A large amount of work has been carried out in the analysis of the shock wave diffraction around conventional geometries such as sharp and rounded corners, but the employment of splitters with lateral variation has hardly attracted the attention of researchers. The investigation of this phenomenon around two-dimensional wedges has allowed the understanding of the basic physical principles of the flow features. On the other hand, important aspects that appear in the third dimension due to the turbulent nature of the vortices are omitted. The lack of studies that use three-dimensional geometries has motivated the current work to experimentally investigate the evolution of the shock wave diffraction around two splitters with spike-shaped structures for Mach numbers of 1.31 and 1.59. Schlieren photography was used to obtain an insight into the sequential diffraction processes that take place in different planes. Interacting among them, these phenomena generate a complicated turbulent cloud with a vortical arrangement.

  5. DNA hydration studied by neutron fiber diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J. [Keele Univ. (United Kingdom)] [and others

    1994-12-31

    The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institute Laue-Langevin, Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformations] transitions in the DNA double-helix.

  6. Integrated Diffractive Optics for Surface Ion Traps

    Science.gov (United States)

    Streed, Erik; Ghadimi, Moji; Blums, Valdis; Norton, Benjamin; Connor, Paul; Amini, Jason; Volin, Curtis; Lobino, Mirko; Kielpinski, David

    2016-05-01

    Photonic interconnects are a bottleneck to achieving large-scale trapped ion quantum computing. We have modified a Georgia Tech Research Institute microwave chip trap by using e-beam lithography to write reflective diffractive collimating optics (80 μm x 127 μm, f=58.6 μm, λ=369.5nm) on the center electrode. The optics have an NA of 0.55 x 0.73, capturing 13.2% of the solid angle. To evaluate the optics 174Yb+ was loaded by isotope selective photo-ionization from a thermal oven and then shuttled to imaging sites. Near diffraction limited sub-wavelength ion images were obtained with an observed spot sized FWHM of 338 nm x 268 nm vs. a diffraction limit of 336 nm x 257 nm. The total photon collection efficiency was measured to be 5.2+/-1.2%. Coupling into a single mode fiber of up to 2.0+/-0.6% was observed, limited by mismatch in the coupling optics. Image mode quality indicates coupling up to 4% may be possible. Funding from Australian Research Council and IARPA.

  7. Microstructure of Horseshoe Nails Using Neutron Diffraction

    Science.gov (United States)

    Goossens, D. J.; Studer, A. J.; Stachurski, Z. H.

    2010-04-01

    Neutron diffraction allows nondestructive testing of the bulk microstructure of mechanical components. The microstructures of horseshoe nails made through three different processes have been explored as a function of position along the nail. Despite all nails being made of similar plain low-carbon steel and being process annealed after manufacture, the microstructures are far from the same. Nails made from strip, using a cold forging stamping process, show narrower diffraction peaks indicating a narrower distribution of lattice parameters and also show diffraction peak intensity ratios closer to those expected for unstrained steel. Thus, the distribution of the orientation of grains in these nails is closer to that of undistorted steel compared to nails made through the other two processes considered—one a drawing from wire and the other a combination of rolling and cold forging. The blades of the drawn nails showed little preferred orientation but the converse was true in the heads. Differing patterns of preferred orientation suggest that the various manufacturing approaches result in substantially different mechanical advantages for the three types of nails, a result in accord with mechanical testing.

  8. Wave diffraction by a cosmic string

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Núñez, Isabel [Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); Institut de Ciències del Cosmos (ICCUB), Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); Bulashenko, Oleg, E-mail: oleg.bulashenko@ub.edu [Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain)

    2016-08-26

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects. - Highlights: • Gravitational waves could help us to reveal cosmic strings – topological defects of early Universe. • Wave diffraction in conical spacetime of a cosmic string is solved analytically. • The Cornu spiral is shown to appear when the string is on the line of sight. • For a string located within our galaxy, the highest amplification would occur at a frequency range of LIGO detector.

  9. Enhanced high-speed coherent diffraction imaging

    Science.gov (United States)

    Potier, Jonathan; Fricker, Sebastien; Idir, Mourad

    2011-03-01

    Due to recent advances in X-ray microscopy, we are now able to image objects with nanometer resolution thanks to Synchrotron beam lines or Free Electron Lasers (FEL). The PCI (Phase Contrast Imaging) is a robust technique that can recover the wavefront from measurements of only few intensity pictures in the Fresnel diffraction region. With our fast straightforward calculus methods, we manage to provide the phase induced by a microscopic specimen in few seconds. We can therefore obtain high contrasted images from transparent materials at very small scales. To reach atomic resolution imaging and thus make a transition from the near to the far field, the Coherent Diffraction Imaging (CDI) technique finds its roots in the analysis of diffraction patterns to obtain the phase of the altered complex wave. Theoretical results about existence and uniqueness of this retrieved piece of information by both iterative and direct algorithms have already been released. However, performances of algorithms remain limited by the coherence of the X-ray beam, presence of random noise and the saturation threshold of the detector. We will present reconstructions of samples using an enhanced version of HIO algorithm improving the speed of convergence and its repeatability. As a first step toward a practical X-Ray CDI system, initial images for reconstructions are acquired with the laser-based CDI system working in the visible spectrum.

  10. Self-action of continuous laser radiation and Pearcey diffraction in a water suspension with light-absorbing particles

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya.; Maksimyak, P. P.;

    2014-01-01

    -diffraction of the incident light, here being strongly sensitive to the medium position with respect to the focus. This technique, based on the complex spatial structure of both the incident and the diffracted fields, can be employed for the detection and measurement of weak non-linearities.......Water suspension of light-absorbing nano-sized particles is an example of a medium in which non-linear effects are present at moderate light intensities favorable for optical treatment of organic and biological objects. We study experimentally the phenomena emerging in a thin layer of such a medium...... under the action of inhomogeneous light field formed due to the Pearcey diffraction pattern near a microlens focus. In this high-gradient field, the light energy absorbed by the particles induces inhomogeneous distribution of the medium refraction index, which results in observable self...

  11. Diffraction efficiency enhancement of femtosecond laser-engraved diffraction gratings due to CO{sub 2} laser polishing

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hun-Kook [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Chosun University, Gwangju (Korea, Republic of); Jung, Deok; Sohn, Ik-Bu; Noh, Young-Chul; Lee, Yong-Tak [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Kim, Jin-Tae [Chosun University, Gwangju (Korea, Republic of); Ahsan, Shamim [Khulna University, Khulna (Bangladesh)

    2014-11-15

    This research demonstrates laser-assisted fabrication of high-efficiency diffraction gratings in fused-silica glass samples. Initially, femtosecond laser pulses are used to engrave diffraction gratings on the glass surfaces. Then, these micro-patterned glass samples undergo CO{sub 2} laser polishing process. unpolished diffraction gratings encoded in the glass samples show an overall diffraction efficiency of 18.1%. diffraction gratings imprinted on the glass samples and then polished four times by using a CO{sub 2} laser beam attain a diffraction efficiency of 32.7%. We also investigate the diffraction patterns of the diffraction gratings encoded on fused-silica glass surfaces. The proposed CO{sub 2} laser polishing technique shows great potential in patterning high-efficiency diffraction gratings on the surfaces of various transparent materials.

  12. Nonlinear robust hierarchical control for nonlinear uncertain systems

    Directory of Open Access Journals (Sweden)

    Leonessa Alexander

    1999-01-01

    Full Text Available A nonlinear robust control-system design framework predicated on a hierarchical switching controller architecture parameterized over a set of moving nominal system equilibria is developed. Specifically, using equilibria-dependent Lyapunov functions, a hierarchical nonlinear robust control strategy is developed that robustly stabilizes a given nonlinear system over a prescribed range of system uncertainty by robustly stabilizing a collection of nonlinear controlled uncertain subsystems. The robust switching nonlinear controller architecture is designed based on a generalized (lower semicontinuous Lyapunov function obtained by minimizing a potential function over a given switching set induced by the parameterized nominal system equilibria. The proposed framework robustly stabilizes a compact positively invariant set of a given nonlinear uncertain dynamical system with structured parametric uncertainty. Finally, the efficacy of the proposed approach is demonstrated on a jet engine propulsion control problem with uncertain pressure-flow map data.

  13. Nonlinear scattering in plasmonic nanostructures

    Science.gov (United States)

    Chu, Shi-Wei

    2016-09-01

    Nonlinear phenomena provide novel light manipulation capabilities and innovative applications. Recently, we discovered nonlinear saturation on single-particle scattering of gold nanospheres by continuous-wave laser excitation and innovatively applied to improve microscopic resolution down to λ/8. However, the nonlinearity was limited to the green-orange plasmonic band of gold nanosphere, and the underlying mechanism has not yet been fully understood. In this work, we demonstrated that nonlinear scattering exists for various material/geometry combinations, thus expanding the applicable wavelength range. For near-infrared, gold nanorod is used, while for blue-violet, silver nanospheres are adopted. In terms of mechanism, the nonlinearity may originate from interband/intraband absorption, hot electron, or hot lattice, which are spectrally mixed in the case of gold nanosphere. For gold nanorod and silver nanosphere, nonlinear scattering occurs at plasmonic resonances, which are spectrally far from interband/intraband absorptions, so they are excluded. We found that the nonlinear index is much larger than possible contributions from hot electrons in literature. Therefore, we conclude that hot lattice is the major mechanism. In addition, we propose that similar to z-scan, which is the standard method to characterize nonlinearity of a thin sample, laser scanning microscopy should be adopted as the standard method to characterize nonlinearity from a nanostructure. Our work not only provides the physical mechanism of the nonlinear scattering, but also paves the way toward multi-color superresolution imaging based on non-bleaching plasmonic scattering.

  14. Discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, Kim Ø; Salerno, M.

    2006-01-01

    A class of discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities is introduced. These equations are derived from the same Hamiltonian using different Poisson brackets and include as particular cases the saturable discrete nonlinear Schrodinger equation and the Ablowi......-Ladik equation. As a common property, these equations possess three kinds of exact analytical stationary solutions for which the Peierls-Nabarro barrier is zero. Several properties of these solutions, including stability, discrete breathers, and moving solutions, are investigated....

  15. Dichromatic nonlinear eigenmodes in slab waveguide with chi(2) nonlinearity.

    Science.gov (United States)

    Darmanyan, S A; Nevière, M

    2001-03-01

    The existence of purely nonlinear eigenmodes in a waveguiding structure composed of a slab with quadratic nonlinearity surrounded by (non)linear claddings is reported. Modes having bright and dark solitonlike shapes and consisting of two mutually locked harmonics are identified. Asymmetrical modes are shown to exist in symmetrical environments. Constraints for the existence of the modes are derived in terms of parameters of guiding structure materials.

  16. Nonlinear Schrodinger equation with chaotic, random, and nonperiodic nonlinearity

    CERN Document Server

    Cardoso, W B; Avelar, A T; Bazeia, D; Hussein, M S

    2009-01-01

    In this paper we deal with a nonlinear Schr\\"{o}dinger equation with chaotic, random, and nonperiodic cubic nonlinearity. Our goal is to study the soliton evolution, with the strength of the nonlinearity perturbed in the space and time coordinates and to check its robustness under these conditions. Comparing with a real system, the perturbation can be related to, e.g., impurities in crystalline structures, or coupling to a thermal reservoir which, on the average, enhances the nonlinearity. We also discuss the relevance of such random perturbations to the dynamics of Bose-Einstein Condensates and their collective excitations and transport.

  17. Electron diffraction of CBr4 in superfluid helium droplets: A step towards single molecule diffraction

    Science.gov (United States)

    He, Yunteng; Zhang, Jie; Kong, Wei

    2016-07-01

    We demonstrate the practicality of electron diffraction of single molecules inside superfluid helium droplets using CBr4 as a testing case. By reducing the background from pure undoped droplets via multiple doping, with small corrections for dimers and trimers, clearly resolved diffraction rings of CBr4 similar to those of gas phase molecules can be observed. The experimental data from CBr4 doped droplets are in agreement with both theoretical calculations and with experimental results of gaseous species. The abundance of monomers and clusters in the droplet beam also qualitatively agrees with the Poisson statistics. Possible extensions of this approach to macromolecular ions will also be discussed. This result marks the first step in building a molecular goniometer using superfluid helium droplet cooling and field induced orientation. The superior cooling effect of helium droplets is ideal for field induced orientation, but the diffraction background from helium is a concern. This work addresses this background issue and identifies a possible solution. Accumulation of diffraction images only becomes meaningful when all images are produced from molecules oriented in the same direction, and hence a molecular goniometer is a crucial technology for serial diffraction of single molecules.

  18. High pressure x-ray diffraction techniques with synchrotron radiation

    Institute of Scientific and Technical Information of China (English)

    刘景

    2016-01-01

    This article summarizes the developments of experimental techniques for high pressure x-ray diffraction (XRD) in diamond anvil cells (DACs) using synchrotron radiation. Basic principles and experimental methods for various diffraction geometry are described, including powder diffraction, single crystal diffraction, radial diffraction, as well as coupling with laser heating system. Resolution in d-spacing of different diffraction modes is discussed. More recent progress, such as extended application of single crystal diffraction for measurements of multigrain and electron density distribution, time-resolved diffraction with dynamic DAC and development of modulated heating techniques are briefl y introduced. The current status of the high pressure beamline at BSRF (Beijing Synchrotron Radiation Facility) and some results are also presented.

  19. Nonlinear Optical Rectennas

    CERN Document Server

    Stolz, A; Markey, L; Francs, G Colas des; Bouhelier, A

    2013-01-01

    We introduce strongly-coupled optical gap antennas to interface optical radiation with current-carrying electrons at the nanoscale. The transducer relies on the nonlinear optical and electrical properties of an optical antenna operating in the tunneling regime. We discuss the underlying physical mechanisms controlling the conversion and demonstrate that a two-wire optical antenna can provide advanced optoelectronic functionalities beyond tailoring the electromagnetic response of a single emitter. Interfacing an electronic command layer with a nanoscale optical device may thus be facilitated by the optical rectennas discussed here.

  20. Nonlinear surface electromagnetic phenomena

    CERN Document Server

    Ponath, H-E

    1991-01-01

    In recent years the physics of electromagnetic surface phenomena has developed rapidly, evolving into technologies for communications and industry, such as fiber and integrated optics. The variety of phenomena based on electromagnetism at surfaces is rich and this book was written with the aim of summarizing the available knowledge in selected areas of the field. The book contains reviews written by solid state and optical physicists on the nonlinear interaction of electromagnetic waves at and with surfaces and films. Both the physical phenomena and some potential applications are

  1. Nonlinear electrodynamics with birefringence

    CERN Document Server

    Kruglov, S I

    2015-01-01

    A new model of nonlinear electrodynamics with three parameters is suggested. The phenomena of vacuum birefringence takes place when there is the external constant magnetic field. We calculate the indices of refraction for two polarizations of electromagnetic waves, parallel and perpendicular to the magnetic induction field. From the Bir\\'{e}fringence Magn\\'{e}tique du Vide (BMV) experiment one of the coefficients, $\\gamma\\approx 10^{-20}$ T$^{-2}$, was estimated. The canonical, symmetrical Belinfante energy-momentum tensors and dilatation current were obtained. The dilatation symmetry and the dual symmetry are broken in the model considered.

  2. Nonlinear diffusion equations

    CERN Document Server

    Wu Zhuo Qun; Li Hui Lai; Zhao Jun Ning

    2001-01-01

    Nonlinear diffusion equations, an important class of parabolic equations, come from a variety of diffusion phenomena which appear widely in nature. They are suggested as mathematical models of physical problems in many fields, such as filtration, phase transition, biochemistry and dynamics of biological groups. In many cases, the equations possess degeneracy or singularity. The appearance of degeneracy or singularity makes the study more involved and challenging. Many new ideas and methods have been developed to overcome the special difficulties caused by the degeneracy and singularity, which

  3. Nonlinear dynamics in psychology

    Directory of Open Access Journals (Sweden)

    Stephen J. Guastello

    2001-01-01

    Full Text Available This article provides a survey of the applications of nonlinear dynamical systems theory to substantive problems encountered in the full scope of psychological science. Applications are organized into three topical areas – cognitive science, social and organizational psychology, and personality and clinical psychology. Both theoretical and empirical studies are considered with an emphasis on works that capture the broadest scope of issues that are of substantive interest to psychological theory. A budding literature on the implications of NDS principles in professional practice is reported also.

  4. Nonlinear Control Systems

    Science.gov (United States)

    2009-11-18

    analytic semigroup T(t) ~ eAl is exponentially stable (Notice that it is also a contraction semigroup ). 3. Be 3(U, Z) and P e £(W, 2) are bounded. 4. Ce...quite often in practice, .4 is self-adjoint. We also note that, since we assume (—A) is sectorial, we work with the semigroup exp(.4f) rather than...Uniform Output Regulation of Nonlinear Sys- tems: A convergent Dynamics Approach, Birkhauser, Boston, 2006. 23 135] A. Pazy, Semigroups of Linear

  5. Nonlinear elliptic systems

    Directory of Open Access Journals (Sweden)

    DJAIRO G. DEFIGUEIREDO

    2000-12-01

    Full Text Available In this paper we treat the question of the existence of solutions of boundary value problems for systems of nonlinear elliptic equations of the form - deltau = f (x, u, v,Ñu,Ñv, - deltav = g(x, u, v, Ñu, Ñv, in omega, We discuss several classes of such systems using both variational and topological methods. The notion of criticality takes into consideration the coupling, which plays important roles in both a priori estimates for the solutions and Palais-Smale conditions for the associated functional in the variational case.

  6. Global Analysis of Nonlinear Dynamics

    CERN Document Server

    Luo, Albert

    2012-01-01

    Global Analysis of Nonlinear Dynamics collects chapters on recent developments in global analysis of non-linear dynamical systems with a particular emphasis on cell mapping methods developed by Professor C.S. Hsu of the University of California, Berkeley. This collection of contributions prepared by a diverse group of internationally recognized researchers is intended to stimulate interests in global analysis of complex and high-dimensional nonlinear dynamical systems, whose global properties are largely unexplored at this time. This book also: Presents recent developments in global analysis of non-linear dynamical systems Provides in-depth considerations and extensions of cell mapping methods Adopts an inclusive style accessible to non-specialists and graduate students Global Analysis of Nonlinear Dynamics is an ideal reference for the community of nonlinear dynamics in different disciplines including engineering, applied mathematics, meteorology, life science, computational science, and medicine.  

  7. Nonlinear evolution of drift instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.W.; Krommes, J.A.; Oberman, C.R.; Smith, R.A.

    1984-01-01

    The nonlinear evolution of collisionless drift instabilities in a shear-free magnetic field has been studied by means of gyrokinetic particle simulation as well as numerical integration of model mode-coupling equations. The purpose of the investigation is to identify relevant nonlinear mechanisms responsible for the steady-state drift wave fluctuations. It is found that the saturation of the instability is mainly caused by the nonlinear E x B convection of the resonant electrons and their associated velocity space nonlinearity. The latter also induces energy exchange between the competing modes, which, in turn, gives rise to enhanced diffusion. The nonlinear E x B convection of the ions, which contributes to the nonlinear frequency shift, is also an important ingredient for the saturation.

  8. Z-scan theory for nonlocal nonlinear media with simultaneous nonlinear refraction and nonlinear absorption.

    Science.gov (United States)

    Rashidian Vaziri, Mohammad Reza

    2013-07-10

    In this paper, the Z-scan theory for nonlocal nonlinear media has been further developed when nonlinear absorption and nonlinear refraction appear simultaneously. To this end, the nonlinear photoinduced phase shift between the impinging and outgoing Gaussian beams from a nonlocal nonlinear sample has been generalized. It is shown that this kind of phase shift will reduce correctly to its known counterpart for the case of pure refractive nonlinearity. Using this generalized form of phase shift, the basic formulas for closed- and open-aperture beam transmittances in the far field have been provided, and a simple procedure for interpreting the Z-scan results has been proposed. In this procedure, by separately performing open- and closed-aperture Z-scan experiments and using the represented relations for the far-field transmittances, one can measure the nonlinear absorption coefficient and nonlinear index of refraction as well as the order of nonlocality. Theoretically, it is shown that when the absorptive nonlinearity is present in addition to the refractive nonlinearity, the sample nonlocal response can noticeably suppress the peak and enhance the valley of the Z-scan closed-aperture transmittance curves, which is due to the nonlocal action's ability to change the beam transverse dimensions.

  9. Results of Soft-Diffraction at LHCb

    CERN Document Server

    Meissner, Marco

    2013-01-01

    The LHCb detector with its unique pseudorapidity coverage allows to perform soft-QCD measurements in the kinematic forward region where QCD models have large uncertainties. Selected analyses related to soft-Diffraction will be summarised in these proceedings. Energy flow and charged particle multiplicity have been measured separately in different event classes. They give input for modelling the underlying event in $pp$ collisions. Prompt hadron ratios are important for hadronisation models, while the $p/p$ ratio is a good observable to test models of baryon number transport.

  10. Diffractive vector meson leptoproduction and spin effects

    CERN Document Server

    Goloskokov, S V

    2006-01-01

    We analyse spin effects in diffractive vector meson leptoproduction at small $x$ on the basis of the generalized parton distribution (GPD) approach. We take into account quark transverse degrees of freedom in the hard subprocess. We calculate amplitudes for the longitudinally and transversely polarized photons and vector mesons. Our results on the cross section and spin density matrix elements (SDME) are in fair agreement with the DESY experiments. Predictions for HERMES and COMPASS energy range are made. The predicted double spin longitudinal $A_{LL}$ asymmetry is not small at HERMES energies

  11. Survival probability in diffractive dijet photoproduction

    CERN Document Server

    Klasen, M

    2009-01-01

    We confront the latest H1 and ZEUS data on diffractive dijet photoproduction with next-to-leading order QCD predictions in order to determine whether a rapidity gap survival probability of less than one is supported by the data. We find evidence for this hypothesis when assuming global factorization breaking for both the direct and resolved photon contributions, in which case the survival probability would have to be E_T^jet-dependent, and for the resolved or in addition the related direct initial-state singular contribution only, where it would be independent of E_T^jet.

  12. Optical image encryption based on diffractive imaging.

    Science.gov (United States)

    Chen, Wen; Chen, Xudong; Sheppard, Colin J R

    2010-11-15

    In this Letter, we propose a method for optical image encryption based on diffractive imaging. An optical multiple random phase mask encoding system is applied, and one of the phase-only masks is selected and laterally translated along a preset direction during the encryption process. For image decryption, a phase retrieval algorithm is proposed to extract a high-quality plaintext. The feasibility and effectiveness of the proposed method are demonstrated by numerical results. The proposed method can provide a new strategy instead of conventional interference methods, and it may open up a new research perspective for optical image encryption.

  13. Oblique Water Wave Diffraction by a Step

    Directory of Open Access Journals (Sweden)

    Dolai P.

    2017-02-01

    Full Text Available This paper is concerned with the problem of diffraction of an obliquely incident surface water wave train on an obstacle in the form of a finite step. Havelock expansions of water wave potentials are used in the mathematical analysis to obtain the physical parameters reflection and transmission coefficients in terms of integrals. Appropriate multi-term Galerkin approximations involving ultraspherical Gegenbauer polynomials are utilized to obtain a very accurate numerical estimate for reflection and transmission coefficients which are depicted graphically. From these figures various interesting results are discussed.

  14. Flexible filamentous virus structure from fiber diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, Gerald; Kendall, Amy; McDonald, Michele; Bian, Wen; Bowles, Timothy; Baumgarten, Sarah; McCullough, Ian; Shi, Jian; Stewart, Phoebe; Bullitt, Esther; Gore, David; Ghabrial, Said (IIT); (BU-M); (Vanderbilt); (Kentucky)

    2008-10-24

    Fiber diffraction data have been obtained from Narcissus mosaic virus, a potexvirus from the family Flexiviridae, and soybean mosaic virus (SMV), a potyvirus from the family Potyviridae. Analysis of the data in conjunction with cryo-electron microscopy data allowed us to determine the symmetry of the viruses and to make reconstructions of SMV at 19 {angstrom} resolution and of another potexvirus, papaya mosaic virus, at 18 {angstrom} resolution. These data include the first well-ordered data ever obtained for the potyviruses and the best-ordered data from the potexviruses, and offer the promise of eventual high resolution structure determinations.

  15. Elastic and diffractive scattering at D0

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Tamsin; /Manchester U.

    2004-04-01

    The first search for diffractively produced Z bosons in the muon decay channel is presented, using a data set collected by the D0 detector at the Fermilab Tevatron at {radical}s = 1.96 TeV between April and September 2003, corresponding to an integrated luminosity of approximately 110 pb{sup -1}. The first dN/d|t| distribution for proton-antiproton elastic scattering at this c.o.m. energy is also presented, using data collected by the D0 Forward Proton Detector between January and May 2002. The measured slope is reproduced by theoretical predictions.

  16. The basics of crystallography and diffraction

    CERN Document Server

    Hammond, C

    2015-01-01

    This title provides a clear and very broadly based introduction to crystallography, light, X-ray, and electron diffraction; a knowledge of which is essential to students in a wide range of scientific disciplines but which is otherwise generally covered in subject-specific and more mathematically detailed texts. The book is also designed to appeal to the more general reader since it shows, by historical and biographical references, how the subject has developed from the work and insights of successive generations of crystallographers and scientists.

  17. Oblique Water Wave Diffraction by a Step

    Science.gov (United States)

    Dolai, P.

    2017-02-01

    This paper is concerned with the problem of diffraction of an obliquely incident surface water wave train on an obstacle in the form of a finite step. Havelock expansions of water wave potentials are used in the mathematical analysis to obtain the physical parameters reflection and transmission coefficients in terms of integrals. Appropriate multi-term Galerkin approximations involving ultraspherical Gegenbauer polynomials are utilized to obtain a very accurate numerical estimate for reflection and transmission coefficients which are depicted graphically. From these figures various interesting results are discussed.

  18. On the interpretation of time-resolved anisotropic diffraction patterns

    DEFF Research Database (Denmark)

    Lorenz, Ulf; Møller, Klaus Braagaard; Henriksen, Niels Engholm

    2010-01-01

    In this paper, we review existing systematic treatments for the interpretation of anisotropic diffraction patterns from partially aligned symmetric top molecules. Such patterns arise in the context of time-resolved diffraction experiments. We calculate diffraction patterns for ground-state NaI ex......I excited with an ultraviolet laser. The results are interpreted with the help of a qualitative analytic model, and general recommendations on the analysis and interpretation of anisotropic diffraction patterns are given....

  19. Quantum Theory for Large Molecules $C_{60}$ Diffraction

    CERN Document Server

    Wu, Xiang-Yao; Liu, Xiao-Jing; Ba, Nuo; Wu, Yi-Heng; Tang, Hou-Li; Wang, Jing; Zhang, Si-Qi

    2011-01-01

    Diffraction phenomena of large molecules have been studied in many experiments, and these experiments are described by many theoretical works. In this paper, we study $C_{60}$ molecules single and double-slit diffraction with quantum theory approach, and we pay close attention to the $C_{60}$ diffraction experiment carried out by A.Zeilinger et.at in 1999. In double-slit diffraction, we consider the decoherence effect, and find the theoretical results are good agreement with experimental data.

  20. A Comment on the Relation between Diffraction and Entropy

    Directory of Open Access Journals (Sweden)

    Michael Baake

    2012-05-01

    Full Text Available Diffraction methods are used to detect atomic order in solids. While uniquely ergodic systems with pure point diffraction have zero entropy, the relation between diffraction and entropy is not as straightforward in general. In particular, there exist families of homometric systems, which are systems sharing the same diffraction, with varying entropy. We summarise the present state of understanding by several characteristic examples.

  1. Topics on nonlinear generalized functions

    CERN Document Server

    Colombeau, J F

    2011-01-01

    The aim of this paper is to give the text of a recent introduction to nonlinear generalized functions exposed in my talk in the congress gf2011, which was asked by several participants. Three representative topics were presented: two recalls "Nonlinear generalized functions and their connections with distribution theory", "Examples of applications", and a recent development: "Locally convex topologies and compactness: a functional analysis of nonlinear generalized functions".

  2. Nonlinear Ultrasonic Phased Array Imaging

    Science.gov (United States)

    Potter, J. N.; Croxford, A. J.; Wilcox, P. D.

    2014-10-01

    This Letter reports a technique for the imaging of acoustic nonlinearity. By contrasting the energy of the diffuse field produced through the focusing of an ultrasonic array by delayed parallel element transmission with that produced by postprocessing of sequential transmission data, acoustic nonlinearity local to the focal point is measured. Spatially isolated wave distortion is inferred without requiring interrogation of the wave at the inspection point, thereby allowing nonlinear imaging through depth.

  3. Nonlinear ultrasonic phased array imaging

    OpenAIRE

    Potter, J N; Croxford, A.J.; Wilcox, P. D.

    2014-01-01

    This Letter reports a technique for the imaging of acoustic nonlinearity. By contrasting the energy of the diffuse field produced through the focusing of an ultrasonic array by delayed parallel element transmission with that produced by postprocessing of sequential transmission data, acoustic nonlinearity local to the focal point is measured. Spatially isolated wave distortion is inferred without requiring interrogation of the wave at the inspection point, thereby allowing nonlinear imaging t...

  4. Research on Nonlinear Dynamical Systems.

    Science.gov (United States)

    1983-01-10

    investigated fundamental aspects of functional differential equations, including qualitative questions (stability, nonlinear oscillations ), in 142,45,47,52...Bifurcation in the Duffing equation with several parameters, II. Proc. of the Royal Society of Edinburgh, Series A, 79A (1977), pp.317-326. 1I.J (with ;Ibtoas...Lecture Notes in Mathematics, Vol. 730 (1979). [54] Nonlinear oscillations in equations with delays. Proc. at A.M.S. 10th Summer Seminar on Nonlinear

  5. Nonlinear ultrasonic phased array imaging.

    Science.gov (United States)

    Potter, J N; Croxford, A J; Wilcox, P D

    2014-10-03

    This Letter reports a technique for the imaging of acoustic nonlinearity. By contrasting the energy of the diffuse field produced through the focusing of an ultrasonic array by delayed parallel element transmission with that produced by postprocessing of sequential transmission data, acoustic nonlinearity local to the focal point is measured. Spatially isolated wave distortion is inferred without requiring interrogation of the wave at the inspection point, thereby allowing nonlinear imaging through depth.

  6. Remote Atmospheric Nonlinear Optical Magnetometry

    Science.gov (United States)

    2014-04-28

    Boyd , Nonlinear Optics (Elsevier, Burlington, MA, 2008). [13] M. Scully and S. Zubairy, Quantum Optics (Cambridge U. Press, Cambridge, UK, 1997...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6703--14-9548 Remote Atmospheric Nonlinear Optical Magnetometry PhilliP SPrangle...b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Remote Atmospheric Nonlinear Optical Magnetometry Phillip Sprangle, Luke

  7. Applications of nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2008-01-01

    * The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

  8. Linearization of conservative nonlinear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Belendez, A; Alvarez, M L [Departamento de Fisica, IngenierIa de Sistemas y TeorIa de la Senal, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain); Fernandez, E; Pascual, I [Departamento de Optica, FarmacologIa y AnatomIa, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)], E-mail: a.belendez@ua.es

    2009-03-11

    A linearization method of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force which allows us to obtain a frequency-amplitude relation which is valid not only for small but also for large amplitudes and, sometimes, for the complete range of oscillation amplitudes. Some conservative nonlinear oscillators are analysed to illustrate the usefulness and effectiveness of the technique.

  9. Noninvasive nonlinear imaging through strongly-scattering turbid layers

    CERN Document Server

    Katz, Ori; Guan, Yefeng; Silberberg, Yaron

    2014-01-01

    Diffraction-limited imaging through complex scattering media is a long sought after goal with important applications in biomedical research. In recent years, high resolution wavefront-shaping has emerged as a powerful approach to generate a sharp focus through highly scattering, visually opaque samples. However, it requires a localized feedback signal from the target point of interest, which necessitates an invasive procedure in all-optical techniques. Here, we show that by exploiting optical nonlinearities, a diffraction-limited focus can be formed inside or through a complex sample, even when the feedback signal is not localized. We prove our approach theoretically and numerically, and experimentally demonstrate it with a two-photon fluorescence signal through highly scattering biological samples. We use the formed focus to perform two-photon microscopy through highly scattering, visually opaque layers.

  10. Problems in nonlinear resistive MHD

    Energy Technology Data Exchange (ETDEWEB)

    Turnbull, A.D.; Strait, E.J.; La Haye, R.J.; Chu, M.S.; Miller, R.L. [General Atomics, San Diego, CA (United States)

    1998-12-31

    Two experimentally relevant problems can relatively easily be tackled by nonlinear MHD codes. Both problems require plasma rotation in addition to the nonlinear mode coupling and full geometry already incorporated into the codes, but no additional physics seems to be crucial. These problems discussed here are: (1) nonlinear coupling and interaction of multiple MHD modes near the B limit and (2) nonlinear coupling of the m/n = 1/1 sawtooth mode with higher n gongs and development of seed islands outside q = 1.

  11. Asymptotics for dissipative nonlinear equations

    CERN Document Server

    Hayashi, Nakao; Kaikina, Elena I; Shishmarev, Ilya A

    2006-01-01

    Many of problems of the natural sciences lead to nonlinear partial differential equations. However, only a few of them have succeeded in being solved explicitly. Therefore different methods of qualitative analysis such as the asymptotic methods play a very important role. This is the first book in the world literature giving a systematic development of a general asymptotic theory for nonlinear partial differential equations with dissipation. Many typical well-known equations are considered as examples, such as: nonlinear heat equation, KdVB equation, nonlinear damped wave equation, Landau-Ginzburg equation, Sobolev type equations, systems of equations of Boussinesq, Navier-Stokes and others.

  12. Focus issue introduction: nonlinear optics.

    Science.gov (United States)

    Boulanger, Benoît; Cundiff, Steven T; Gauthier, Daniel J; Karlsson, Magnus; Lu, Yan-Qing; Norwood, Robert A; Skryabin, Dmitry; Taira, Takunori

    2011-11-07

    It is now fifty years since the original observation of second harmonic generation ushered in the field of nonlinear optics, close on the heels of the invention of the laser. This feature issue celebrates this anniversary with papers that span the range from new nonlinear optical materials, through the increasingly novel methods that have been developed for phase matching, to emerging areas such as nonlinear metamaterials and plasmonic enhancement of optical properties. It is clear that the next fifty years of nonlinear optics will witness a proliferation of new applications with increasing technological impact.

  13. Nonlocal homogenization for nonlinear metamaterials

    CERN Document Server

    Gorlach, Maxim A; Lapine, Mikhail; Kivshar, Yuri S; Belov, Pavel A

    2016-01-01

    We present a consistent theoretical approach for calculating effective nonlinear susceptibilities of metamaterials taking into account both frequency and spatial dispersion. Employing the discrete dipole model, we demonstrate that effects of spatial dispersion become especially pronounced in the vicinity of effective permittivity resonance where nonlinear susceptibilities reach their maxima. In that case spatial dispersion may enable simultaneous generation of two harmonic signals with the same frequency and polarization but different wave vectors. We also prove that the derived expressions for nonlinear susceptibilities transform into the known form when spatial dispersion effects are negligible. In addition to revealing new physical phenomena, our results provide useful theoretical tools for analysing resonant nonlinear metamaterials.

  14. Nonlinear Peltier effect in semiconductors

    Science.gov (United States)

    Zebarjadi, Mona; Esfarjani, Keivan; Shakouri, Ali

    2007-09-01

    Nonlinear Peltier coefficient of a doped InGaAs semiconductor is calculated numerically using the Monte Carlo technique. The Peltier coefficient is also obtained analytically for single parabolic band semiconductors assuming a shifted Fermi-Dirac electronic distribution under an applied bias. Analytical results are in agreement with numerical simulations. Key material parameters affecting the nonlinear behavior are doping concentration, effective mass, and electron-phonon coupling. Current density thresholds at which nonlinear behavior is observable are extracted from numerical data. It is shown that the nonlinear Peltier effect can be used to enhance cooling of thin film microrefrigerator devices especially at low temperatures.

  15. Diffractions from the brane and GW150914

    CERN Document Server

    Gogberashvili, Merab

    2016-01-01

    In the braneworld scenario the zero mode gravitons are trapped on a brane due to non-linear warping effect, so that gravitational waves can reflect from the brane walls. If the reflected waves form an interference pattern on the brane then it can be detected on existing detectors due to spatial variations of intensity in the pattern. As an example we interpret the LIGO event GW150914 as a manifestation of such interference pattern produced by the burst gravitational waves, emitted by a powerful source inside or outside the brane and reflected from the brane walls.

  16. Nonlinearities in Behavioral Macroeconomics.

    Science.gov (United States)

    Gomes, Orlando

    2017-07-01

    This article undertakes a journey across the literature on behavioral macroeconomics, with attention concentrated on the nonlinearities that the behavioral approach typically suggests or implies. The emphasis is placed on thinking the macro economy as a living organism, composed of many interacting parts, each one having a will of its own, which is in sharp contrast with the mechanism of the orthodox view (well represented by the neoclassical or new Keynesian dynamic stochastic general equilibrium - DSGE - model). The paper advocates that a thorough understanding of individual behavior in collective contexts is the only possible avenue to further explore macroeconomic phenomena and the often observed 'anomalies' that the benchmark DSGE macro framework is unable to explain or justify. After a reflection on the role of behavioral traits as a fundamental component of a new way of thinking the economy, the article proceeds with a debate on some of the most relevant frameworks in the literature that somehow link macro behavior and nonlinearities; covered subjects include macro models with disequilibrium rules, agent-based models that highlight interaction and complexity, evolutionary switching frameworks, and inattention based decision problems. These subjects have, as a fundamental point in common, the use of behavioral elements to transform existing interpretations of the economic reality, making it more evident how irregular fluctuations emerge and unfold on the aggregate.

  17. Improved nonlinear prediction method

    Science.gov (United States)

    Adenan, Nur Hamiza; Md Noorani, Mohd Salmi

    2014-06-01

    The analysis and prediction of time series data have been addressed by researchers. Many techniques have been developed to be applied in various areas, such as weather forecasting, financial markets and hydrological phenomena involving data that are contaminated by noise. Therefore, various techniques to improve the method have been introduced to analyze and predict time series data. In respect of the importance of analysis and the accuracy of the prediction result, a study was undertaken to test the effectiveness of the improved nonlinear prediction method for data that contain noise. The improved nonlinear prediction method involves the formation of composite serial data based on the successive differences of the time series. Then, the phase space reconstruction was performed on the composite data (one-dimensional) to reconstruct a number of space dimensions. Finally the local linear approximation method was employed to make a prediction based on the phase space. This improved method was tested with data series Logistics that contain 0%, 5%, 10%, 20% and 30% of noise. The results show that by using the improved method, the predictions were found to be in close agreement with the observed ones. The correlation coefficient was close to one when the improved method was applied on data with up to 10% noise. Thus, an improvement to analyze data with noise without involving any noise reduction method was introduced to predict the time series data.

  18. Non-linear Young's double-slit experiment.

    Science.gov (United States)

    San Roman, Julio; Ruiz, Camilo; Perez, Jose Antonio; Delgado, Diego; Mendez, Cruz; Plaja, Luis; Roso, Luis

    2006-04-01

    The Young's double slit experiment is recreated using intense and short laser pulses. Our experiment evidences the role of the non-linear Kerr effect in the formation of interference patterns. In particular, our results evidence a mixed mechanism in which the zeroth diffraction order of each slit are mainly affected by self-focusing and self-phase modulation, while the higher orders propagate linearly. Despite of the complexity of the general problem of non-linear propagation, we demonstrate that this experiment retains its simplicity and allows for a geometrical interpretation in terms of simple optical paths. In consequence, our results may provide key ideas on experiments on the formation of interference patterns with intense laser fields in Kerr media.

  19. NONLINEAR FREE SURFACE ACTION WITH AN ARRAY OF VERTICAL CYLINDERS

    Institute of Scientific and Technical Information of China (English)

    HUANG J. B.

    2004-01-01

    Nonlinear diffraction of regular waves by an array of bottom-seated circular cylinders is investigated in frequency domain, based on a Stokes expansion approach. A complete semi-analytical solution is developed which allows an efficient evaluation of the second-order potentials in the entire fluid domain, and the wave forces on the structure. Expressions are derived for the second-order potential in the vicinity of individual cylinders. These expressions have a simple form, thus providing an effective means for investigating the wave enhancement due to nonlinear interactions with multiple cylinders. Based on the present method, the wave run-up and free-surface elevations around an array of two, three and four cylinders are investigated numerically.

  20. High diffraction efficiency of three-layer diffractive optics designed for wide temperature range and large incident angle.

    Science.gov (United States)

    Mao, Shan; Cui, Qingfeng; Piao, Mingxu; Zhao, Lidong

    2016-05-01

    A mathematical model of diffraction efficiency and polychromatic integral diffraction efficiency affected by environment temperature change and incident angle for three-layer diffractive optics with different dispersion materials is put forward, and its effects are analyzed. Taking optical materials N-FK5 and N-SF1 as the substrates of multilayer diffractive optics, the effect on diffraction efficiency and polychromatic integral diffraction efficiency with intermediate materials POLYCARB is analyzed with environment temperature change as well as incident angle. Therefore, three-layer diffractive optics can be applied in more wide environmental temperature ranges and larger incident angles for refractive-diffractive hybrid optical systems, which can obtain better image quality. Analysis results can be used to guide the hybrid imaging optical system design for optical engineers.

  1. Optical nonlinearities of iron doped zinc sulphide quantum dots

    Science.gov (United States)

    Cinumon, K. V.; Prasanth, S.; Raj, D. Rithesh; Vineeshkumar, T. V.; Pillai, V. P. Mahadevan; Sudarsanakumar, C.

    2017-05-01

    Polyethylene glycol (PEG) capped pure and Fe doped ZnS nanoparticles were successfully synthesized by chemical precipitation method. Cubic zinc blende phase of the samples was confirmed from X-ray diffraction. The average grain size was found to be in the range of 2-3 nm and was confirmed with TEM. The undoped and doped ZnS samples show blue emission with emission wavelength at 360 nm. A rapid luminescence quenching with increasing dopant concentration was observed. The nonlinear absorption coefficients of the doped and undoped samples were calculated using Z-scan technique.

  2. Synchrotron powder diffraction on Aztec blue pigments

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez del Rio, M. [European Synchrotron Radiation Facility, B.P. 220, Grenoble Cedex (France); Gutierrez-Leon, A.; Castro, G.R.; Rubio-Zuazo, J. [Spanish CRG Beamline at the European Synchrotron Radiation Facility, SpLine, B.P. 220, Grenoble Cedex (France); Solis, C. [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico, D.F. (Mexico); Sanchez-Hernandez, R. [INAH Subdireccion de Laboratorios y Apoyo Academico, Mexico, D.F. (Mexico); Robles-Camacho, J. [INAH Centro Regional Michoacan, Morelia, Michoacan (Mexico); Rojas-Gaytan, J. [INAH Direccion de Salvamento Arqueologico, Naucalpan de Juarez (Mexico)

    2008-01-15

    Some samples of raw blue pigments coming from an archaeological rescue mission in downtown Mexico City have been characterized using different techniques. The samples, some recovered as a part of a ritual offering, could be assigned to the late Aztec period (XVth century). The striking characteristic of these samples is that they seem to be raw pigments prior to any use in artworks, and it was possible to collect a few {mu}g of pigment after manual grain selection under a microscopy monitoring. All pigments are made of indigo, an organic colorant locally known as anil or xiuhquilitl. The colorant is always found in combination with an inorganic matrix, studied by powder diffraction. In one case the mineral base is palygorskite, a rare clay mineral featuring micro-channels in its structure, well known as the main ingredient of the Maya blue pigment. However, other samples present the minerals sepiolite (a clay mineral of the palygorskite family) and calcite. Another sample contains barite, a mineral never reported in prehispanic paints. We present the results of characterization using high resolution powder diffraction recorded at the European Synchrotron Radiation Facility (BM25A, SpLine beamline) complemented with other techniques. All of them gave consistent results on the composition. A chemical test on resistance to acids was done, showing a high resistance for the palygorskite and eventually sepiolite compounds, in good agreement with the excellent resistance of the Maya blue. (orig.)

  3. Imaging molecular structure with photoelectron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Boll, Rebecca

    2014-07-02

    The possibility to study the structure of polyatomic gas-phase molecules by photoelectron diffraction is investigated with the goal of developing a method capable of imaging ultrafast photochemical reactions with femtosecond temporal and sub-Angstroem spatial resolution. The fluorine 1s-level of adiabatically laser-aligned 1-ethynyl-4-fluorobenzene (C{sub 8}H{sub 5}F) molecules was ionized by X-ray pulses from the Linac Coherent Light Source Free-Electron Laser, and the angular distributions of photoelectrons with kinetic energies between 30 and 60 eV were recorded by velocity map imaging. Comparison with density functional theory calculations allows relating the measured distributions to the molecular structure. The results of an IR-pump, X-ray-probe experiment on aligned 1,4-dibromobenzene (C{sub 6}H{sub 4}Br{sub 2})molecules are presented to explore the potential of photoelectron diffraction for time-resolved imaging. The influence of the alignment laser pulse on the pumping and probing step is discussed. Laser-alignment is contrasted with determination of the molecular orientation by photoelectron-photoion coincidences for an exemplary data set on 1-ethynyl-4-fluorobenzene molecules recorded at the PETRA III synchrotron. Both methods are evaluated with respect to their applicability to record time-dependent snapshots of molecular structure. The results obtained in this work indicate possible future avenues for investigating ultrafast molecular dynamics using X-ray Free-Electron Lasers.

  4. Multidataset Refinement Resonant Diffraction, and Magnetic Structures.

    Science.gov (United States)

    Attfield, J Paul

    2004-01-01

    The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset refinement is now commonplace; the datasets may be from different detectors, e.g., in a time-of-flight experiment, or from separate experiments, such as at several x-ray energies giving resonant information. The complementary use of x rays and neutrons is exemplified by a recent combined refinement of the monoclinic superstructure of magnetite, Fe3O4, below the 122 K Verwey transition, which reveals evidence for Fe(2+)/Fe(3+) charge ordering. Powder neutron diffraction data continue to be used for the solution and Rietveld refinement of magnetic structures. Time-of-flight instruments on cold neutron sources can produce data that have a high intensity and good resolution at high d-spacings. Such profiles have been used to study incommensurate magnetic structures such as FeAsO4 and β-CrPO4. A multiphase, multidataset refinement of the phase-separated perovskite (Pr0.35Y0.07Th0.04Ca0.04Sr0.5)MnO3 has been used to fit three components with different crystal and magnetic structures at low temperatures.

  5. ATLAS results on diffraction and exclusive production

    CERN Document Server

    Tasevsky, Marek; The ATLAS collaboration

    2016-01-01

    The ATLAS collaboration has carried out a study of diffractive dijet production at 7 TeV pp collisions at the LHC, i.e. events with a hadronic system containing at least two jets in addition to a large region of pseudorapidity devoid of hadronic activity. The data distributions are compared with Monte Carlo models and the rapidity gap survival probability has been estimated in the kinematic region with high diffractive contribution. In the absence of forward proton tagging, exclusive processes can be distinguished in the central part of the ATLAS detector exploiting the large rapidity gap in the central region and the absence of charged particles reconstructed in the inner tracking detector. This strategy has been exploited to study the exclusive production of dilepton pairs in the data taken at centreofmass energies of 7 and 8 TeV. The 7 TeV study concentrates on a precision measurement of the dielectron and dimuon process, while the 8 TeV measurement explores the exclusive production of WW pairs in the elec...

  6. Applications of TOF neutron diffraction in archaeometry

    Energy Technology Data Exchange (ETDEWEB)

    Kockelmann, W. [Rutherford Appleton Laboratory, ISIS Facility, Chilton (United Kingdom); Siano, S.; Bartoli, L. [Istituto di Fisica Applicata - CNR, Sesto Fiorentino (Italy); Visser, D. [Rutherford Appleton Laboratory, ISIS Facility, Chilton (United Kingdom); Netherlands Organisation for Scientific Research (NWO), Den Haag (Netherlands); Hallebeek, P. [Netherlands Institute for Cultural Heritage (ICN), Amsterdam (Netherlands); Traum, R. [Kunsthistorisches Museum Wien, Muenzkabinett, Vienna (Austria); Linke, R.; Schreiner, M. [Akademie der Bildenden Kuenste, Institut fuer Wissenschaften und Technologien in der Kunst, Vienna (Austria); Kirfel, A. [Universitaet Bonn, Mineralogisch-Petrologisches Institut, Bonn (Germany)

    2006-05-15

    Neutron radiation meets the demand for a versatile diagnostic probe for collecting information from the interior of large, undisturbed museum objects or archaeological findings. Neutrons penetrate through coatings and corrosion layers deep into centimetre-thick materials, a property that makes them ideal for non-destructive examination of objects for which sampling is impractical or unacceptable. A particular attraction of neutron techniques for archaeologists and conservation scientists is the prospect of locating hidden materials and structures inside objects. Time-of-flight (TOF) neutron diffraction allows for the examination of mineral and metal phase contents, crystal structures, grain orientations, and microstructures as well as micro- and macro strains. A promising application is texture analysis which may provide clues to the deformation history of the material, and hence to specific working processes. Here we report on instructive examples of TOF neutron diffraction, including phase analyses of medieval Dutch tin-lead spoons, texture analyses of bronze specimens as well as of 16th-century silver coins. (orig.)

  7. Quantum vortices and trajectories in particle diffraction

    CERN Document Server

    Delis, N; Contopoulos, G

    2011-01-01

    We investigate the phenomenon of the diffraction of charged particles by thin material targets using the method of the de Broglie-Bohm quantum trajectories. The particle wave function can be modeled as a sum of two terms $\\psi=\\psi_{ingoing}+\\psi_{outgoing}$. A thin separator exists between the domains of prevalence of the ingoing and outgoing wavefunction terms. The structure of the quantum-mechanical currents in the neighborhood of the separator implies the formation of an array of \\emph{quantum vortices}. The flow structure around each vortex displays a characteristic pattern called `nodal point - X point complex'. The X point gives rise to stable and unstable manifolds. We find the scaling laws characterizing a nodal point-X point complex by a local perturbation theory around the nodal point. We then analyze the dynamical role of vortices in the emergence of the diffraction pattern. In particular, we demonstrate the abrupt deflections, along the direction of the unstable manifold, of the quantum trajector...

  8. Neutron diffraction study of austempered ductile iron

    Science.gov (United States)

    Choi, C. S.; Sharpe, W.; Barker, J.; Fields, R. J.

    1996-04-01

    Crystallographic properties of an austempered ductile iron (ADI) were studied by using neutron diffraction. A quantitative phase analysis based on Rietveld refinements revealed three component phases, α-Fe (ferrite), γ-Fe (austenite), and graphite precipitate, with weight fractions of 66.0, 31.5, and 2.5 pct, respectively. The ferrite phases of the samples were found to be tetragonal, 14/mmm, with a c/a ratio of about 0.993, which is very close to the body-centered cubic (bcc) structure. The austenite phase had C atoms occupying the octahedral site of the face-centered cubic (fcc) unit cell with about 8 pct occupancy ratio. A strong microstrain broadening was observed for the two Fe phases of the samples. The particle sizes of the acicular ferrite phase were studied by using small angle neutron scattering. The analysis suggested a mean rod diameter of 700 A. The scattering invariant predicts a ferrite volume fraction consistent with the powder diffraction analysis. A textbook case of nodular graphite segregation, with average diameters ranging from 10 to 20 μm, was observed by optical micrography.

  9. Diffraction limited spectro-polarimeter - Phase I

    Science.gov (United States)

    Sankarasubramanian, Kasiviswanathan; Elmore, David F.; Lites, Bruce W.; Sigwarth, Michael; Rimmele, Thomas R.; Hegwer, Steven L.; Gregory, Scott; Streander, Kim V.; Wilkins, Lawrence M.; Richards, K.; Berst, C.

    2003-02-01

    A diffraction limited spectro-polarimeter is under construction at the National Solar Observatory in collaboration with the High Altitude Observatory. The scientific objective of the project is to measure the magnetic fields on the Sun up to the diffraction limit of the Dunn Solar Telescope. The same instrument would also measure the magnetic field of large sunspots or sunspot groups with reasonable spatial resolution. This requires a flexible image scale which cannot be obtained with the current Advanced Stokes Polarimeter (ASP) without loosing 50% of the light. The new spectro-polarimeter is designed in such a way that the image scale can be changed without loosing much light. It can work either in high-spatial resolution mode (0.09 arcsec per pixel) with a small field of view (FOV: 65 arcsec) or in large FOV mode (163 arcsec) with low-spatial resolution (0.25 arcsec per pixel). The phase-I of this project is to design and build the spectrograph with flexible image scale. Using the existing modulation, calibration optics of the ASP and the ASP control and data acquisition system with ASP-CHILL camera, the spectrograph was tested for its performance. This paper will concentrate on the performance of the spectrograph and will discuss some preliminary results obtained with the test runs.

  10. Inversion of diffraction data for amorphous materials

    Science.gov (United States)

    Pandey, Anup; Biswas, Parthapratim; Drabold, D. A.

    2016-09-01

    The general and practical inversion of diffraction data-producing a computer model correctly representing the material explored-is an important unsolved problem for disordered materials. Such modeling should proceed by using our full knowledge base, both from experiment and theory. In this paper, we describe a robust method to jointly exploit the power of ab initio atomistic simulation along with the information carried by diffraction data. The method is applied to two very different systems: amorphous silicon and two compositions of a solid electrolyte memory material silver-doped GeSe3. The technique is easy to implement, is faster and yields results much improved over conventional simulation methods for the materials explored. By direct calculation, we show that the method works for both poor and excellent glass forming materials. It offers a means to add a priori information in first-principles modeling of materials, and represents a significant step toward the computational design of non-crystalline materials using accurate interatomic interactions and experimental information.

  11. Crystal diffraction lens for medical imaging

    Science.gov (United States)

    Smither, Robert K.; Roa, Dante E.

    2000-04-01

    A crystal diffraction lens for focusing energetic gamma rays has been developed at Argonne National Laboratory for use in medical imaging of radioactivity in the human body. A common method for locating possible cancerous growths in the body is to inject radioactivity into the blood stream of the patient and then look for any concentration of radioactivity that could be associated with the fast growing cancer cells. Often there are borderline indications of possible cancers that could be due to statistical functions in the measured counting rates. In order to determine if these indications are false or real, one must resort to surgical means and take tissue samples in the suspect area. We are developing a system of crystal diffraction lenses that will be incorporated into a 3- D imaging system with better sensitivity (factors of 10 to 20) and better spatial resolution (a few mm in both vertical and horizontal directions) than most systems presently in use. The use of this new imaging system will allow one to eliminate 90 percent of the false indications and both locate and determine the size of the cancer with mm precision. The lens consists of 900 single crystals of copper, 4 mm X 4 mm on a side and 2 - 4 mm thick, mounted in 13 concentric rings.

  12. Nonlinear Response of Strong Nonlinear System Arisen in Polymer Cushion

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2013-01-01

    Full Text Available A dynamic model is proposed for a polymer foam-based nonlinear cushioning system. An accurate analytical solution for the nonlinear free vibration of the system is derived by applying He's variational iteration method, and conditions for resonance are obtained, which should be avoided in the cushioning design.

  13. Analysis of X-Ray Diffraction as a Probe of Interdiffusion in Si/SiGe Heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Sean M

    2003-08-20

    We investigate numerical simulations that utilize a non-linear interdiffusion solver and dynamical x-ray diffraction calculations to predict the local composition evolution in low Ge concentration Si/SiGe superlattices and their diffraction patterns during annealing. Superlattice satellite peak decay rates are compared with experimentally measured values and simulated diffraction patterns are matched directly to data with good success. The simulations are used to test the sensitivity of x-ray diffraction to various uncertainties commonly encountered when measuring interdiffusion at Si/SiGe interfaces. It is found that the most serious errors result from variations in the Ge content across the surface of the wafer. For example, the resolution limit of most experimental techniques used to measure Ge concentration in a SiGe film is -1 at.%, for a film with 11% mean Ge concentration annealed for 5 hours at 870 C, this level of error will cause the observed interdiffusivity values to deviate by -25% or +50%. The simulations are further used to show that for Si/SiGe interdiffusion, superlattice diffraction produces valid measurements when applied to 004 superlattice satellite peaks and square wave composition modulations even though it is only exactly applicable to satellite peaks about 000 reflection and to sinusoidal composition modulations. Finally, we show that proper interpretation of x-ray scattering data to extract Si/SiGe interdiffusivity values must account for the strong dependence of the interdiffusivity on Ge concentration.

  14. X-Ray Diffraction Analysis of NLO Crystals: Traditional Applications and More New Opportunities

    Science.gov (United States)

    Antipin, Mikhail Yu.; Clark, Ronald D.; Nesterov, Vladimir N.

    1998-01-01

    Single crystal X-ray diffraction analysis is one of the more important methods for the molecular and crystal structure determination of matter and therefore it has a great importance in material science including design and engineering of different compounds with non-linear optical (NLO) properties. It was shown in our previous publications that this method provides unique information about molecular structure of NLO compounds, their crystal symmetry and crystal packing arrays, molecular conformation and geometries and many other structural and electronic characteristics that are important for understanding the nature of NLO properties of solids. A very new application of the X-ray diffraction method is related to analysis of the electron density distribution p(r) in crystals and some of its characteristics (atomic and group charges, dipole and higher multipole moments, etc.), that may be obtained directly form the diffraction measurements. In the present work, we will discuss our preliminary low temperature high-resolution X-ray data for the m-nitroaniline (mNA) single crystal (VI). This is one of the "classical" organic NLO materials and electron density distribution analysis in this simple compound has a great scientific interest.

  15. Higher Order Diffraction Characteristics of Fiber Bragg Grating

    Directory of Open Access Journals (Sweden)

    Sunita P. Ugale

    2013-02-01

    Full Text Available The effect of grating saturation on higher order diffraction characteristic of FBG is investigated by using Coupled mode theory. Grating saturation effects were considered in the index distribution model showing the significant influence on the coupling process and hence on the reflectivity characteristics of FBG. Maximum reflectivity curves for first and higher order diffraction of FBG are plotted for different values of saturation coefficient. The effect of change in length and change in refractive index are studied. The behavior of grating for higher order of diffraction is totally different than first order of diffraction. In saturated gratings, the higher order diffraction can be utilized for multiparameter sensing

  16. A new bridge technique for neutron tomography and diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burca, G., E-mail: G.Burca@open.ac.uk [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); James, J.A. [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); Kockelmann, W. [ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Fitzpatrick, M.E. [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); Zhang, S.Y. [ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Hovind, J. [Paul Scherrer Institute (PSI), CH-5232, Villigen (Switzerland); Langh, R. van [Delft University of Technology, Department of Materials Science, Faculty 3mE, Mekelweg 2, 2628 CD Delft (Netherlands); Rijksmuseum Amsterdam, P.O. Box 74888, 1070 DN Amsterdam (Netherlands)

    2011-09-21

    An attractive feature of neutron techniques is the ability to identify hidden materials and structures inside engineering components and objects of art and archaeology. Bearing this in mind we are investigating a new technique, 'Tomography Driven Diffraction' (TDD), that exploits tomography data to guide diffraction experiments on samples with complex structures and shapes. The technique can be used utilising combinations of individual tomography and diffraction instruments, such as NEUTRA (PSI, CH) and ENGIN-X (ISIS, UK), but is also suitable for new combined imaging and diffraction instruments such as the JEEP synchrotron engineering instrument (DIAMOND, UK) and the proposed IMAT neutron imaging and diffraction instrument (ISIS, UK).

  17. Highly Nonlinear Luminescence Induced by Gold Nanoparticles on Glass Surfaces with Continuous-Wave Laser Illumination

    CERN Document Server

    Wu, Yong; Toro, Ligia; Stefani, Enrico

    2015-01-01

    We report on highly nonlinear luminescence being observed from individual spherical gold nanoparticles immobilized on a borosilicate glass surface and illuminated by continuous-wave (CW) lasers with relatively low power. The nonlinear luminescence shows optical super-resolution beyond the diffraction limit in three dimensions compared to the scatting of the excitation laser light. The luminescence intensity from most nanoparticles is proportional to the 5th--7th power of the excitation laser power and has wide excitation and emission spectra across the visible wavelength range. Strong nonlinear luminescence is only observed near the glass surface. High optical nonlinearity excited by low CW laser power is related to a long-lived dark state of the gold nanoparticles, where the excitation light is strongly absorbed. This phenomenon has potential biological applications in super-resolution and deep tissue imaging.

  18. Nonlinear continuous-wave optical propagation in nematic liquid crystals: Interplay between reorientational and thermal effects

    Science.gov (United States)

    Alberucci, Alessandro; Laudyn, Urszula A.; Piccardi, Armando; Kwasny, Michał; Klus, Bartlomiej; Karpierz, Mirosław A.; Assanto, Gaetano

    2017-07-01

    We investigate nonlinear optical propagation of continuous-wave (CW) beams in bulk nematic liquid crystals. We thoroughly analyze the competing roles of reorientational and thermal nonlinearity with reference to self-focusing/defocusing and, eventually, the formation of nonlinear diffraction-free wavepackets, the so-called spatial optical solitons. To this extent we refer to dye-doped nematic liquid crystals in planar cells excited by a single CW beam in the highly nonlocal limit. To adjust the relative weight between the two nonlinear responses, we employ two distinct wavelengths, inside and outside the absorption band of the dye, respectively. Different concentrations of the dye are considered in order to enhance the thermal effect. The theoretical analysis is complemented by numerical simulations in the highly nonlocal approximation based on a semi-analytic approach. Theoretical results are finally compared to experimental results in the Nematic Liquid Crystals (NLC) 4-trans-4'-n-hexylcyclohexylisothiocyanatobenzene (6CHBT) doped with Sudan Blue dye.

  19. Inclusive transverse momentum distributions of charged particles in diffractive and non-diffractive photoproduction at HERA

    CERN Document Server

    Derrick, Malcolm; Magill, S; Mikunas, D; Musgrave, B; Repond, J; Stanek, R; Talaga, R L; Zhang, H; Ayad, R; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Bruni, P; Cara Romeo, G; Castellini, G; Chiarini, M; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; Gialas, I; Giusti, P; Iacobucci, G; Laurenti, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Nemoz, C; Palmonari, F; Polini, A; Sartorelli, G; Timellini, R; Zamora-Garcia, Yu E; Zichichi, Antonino; Bargende, A; Crittenden, James Arthur; Desch, Klaus; Diekmann, B; Doeker, T; Eckert, M; Feld, L; Frey, A; Geerts, M; Geitz, G; Grothe, M; Haas, T; Hartmann, H; Haun, D; Heinloth, K; Hilger, E; Jakob, H P; Katz, U F; Mari, S M; Mass, A; Mengel, S; Mollen, J; Paul, E; Rembser, C; Schattevoy, R; Schramm, D; Stamm, J; Wedemeyer, R; Campbell-Robson, S; Cassidy, A; Dyce, N; Foster, B; George, S; Gilmore, R; Heath, G P; Heath, H F; Llewellyn, T J; Morgado, C J S; Norman, D J P; O'Mara, J A; Tapper, R J; Wilson, S S; Yoshida, R; Rau, R R; Arneodo, M; Iannotti, L; Schioppa, M; Susinno, G; Bernstein, A M; Caldwell, A; Cartiglia, N; Parsons, J A; Ritz, S; Sciulli, F; Straub, P B; Wai, L; Yang, S; Zhu, Q; Borzemski, P; Chwastowski, J; Eskreys, Andrzej; Piotrzkowski, K; Zachara, M; Zawiejski, L; Adamczyk, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowalski, T; Rulikowska-Zarebska, E; Suszycki, L; Zajac, J; Kotanski, Andrzej; Przybycien, M B; Bauerdick, L A T; Behrens, U; Beier, H; Bienlein, J K; Coldewey, C; Deppe, O; Desler, K; Drews, G; Flasinski, M; Gilkinson, D J; Glasman, C; Göttlicher, P; Grosse-Knetter, J; Gutjahr, B; Hain, W; Hasell, D; Hessling, H; Iga, Y; Joos, P; Kasemann, M; Klanner, Robert; Koch, W; Köpke, L; Kötz, U; Kowalski, H; Labs, J; Ladage, A; Löhr, B; Loewe, M; Lüke, D; Manczak, O; Monteiro, T; Ng, J S T; Nickel, S; Notz, D; Ohrenberg, K; Roco, M T; Rohde, M; Roldán, J; Schneekloth, U; Schulz, W; Selonke, F; Stiliaris, E; Surrow, B; Voss, T; Westphal, D; Wolf, G; Youngman, C; Zhou, J F; Grabosch, H J; Kharchilava, A I; Leich, A; Mattingly, M C K; Meyer, A; Schlenstedt, S; Wulff, N; Barbagli, G; Pelfer, P G; Anzivino, Giuseppina; Maccarrone, G D; De Pasquale, S; Votano, L; Bamberger, Andreas; Eisenhardt, S; Freidhof, A; Söldner-Rembold, S; Schröder, J; Trefzger, T M; Brook, N H; Bussey, Peter J; Doyle, A T; Fleck, I; Saxon, D H; Utley, M L; Wilson, A S; Dannemann, A; Holm, U; Horstmann, D; Neumann, T; Sinkus, R; Wick, K; Badura, E; Burow, B D; Hagge, L; Lohrmann, E; Mainusch, J; Milewski, J; Nakahata, M; Pavel, N; Poelz, G; Schott, W; Zetsche, F; Bacon, Trevor C; Butterworth, Ian; Gallo, E; Harris, V L; Hung, B Y H; Long, K R; Miller, D B; Morawitz, P P O; Prinias, A; Sedgbeer, J K; Whitfield, A F; Mallik, U; McCliment, E; Wang, M Z; Wang, S M; Wu, J T; Zhang, Y; Cloth, P; Filges, D; An Shiz Hong; Hong, S M; Nam, S W; Park, S K; Suh, M H; Yon, S H; Imlay, R; Kartik, S; Kim, H J; McNeil, R R; Metcalf, W; Nadendla, V K; Barreiro, F; Cases, G; Graciani, R; Hernández, J M; Hervás, L; Labarga, L; Del Peso, J; Puga, J; Terrón, J; De Trocóniz, J F; Smith, G R; Corriveau, F; Hanna, D S; Hartmann, J; Hung, L W; Lim, J N; Matthews, C G; Patel, P M; Sinclair, L E; Stairs, D G; Saint-Laurent, M G; Ullmann, R T; Zacek, G; Bashkirov, V; Dolgoshein, B A; Stifutkin, A; Bashindzhagian, G L; Ermolov, P F; Gladilin, L K; Golubkov, Yu A; Kobrin, V D; Kuzmin, V A; Proskuryakov, A S; Savin, A A; Shcheglova, L M; Solomin, A N; Zotov, N P; Botje, M; Chlebana, F S; Dake, A P; Engelen, J; De Kamps, M; Kooijman, P M; Kruse, A; Tiecke, H G; Verkerke, W; Vreeswijk, M; Wiggers, L; De Wolf, E; Van Woudenberg, R; Acosta, D; Bylsma, B G; Durkin, L S; Honscheid, K; Li Chuan; Ling, T Y; McLean, K W; Murray, W N; Park, I H; Romanowsky, T A; Seidlein, R; Bailey, D S; Blair, G A; Byrne, A; Cashmore, Roger J; Cooper-Sarkar, A M; Daniels, D C; Devenish, R C E; Harnew, N; Lancaster, M; Luffman, P; Lindemann, L; McFall, J D; Nath, C; Noyes, V A; Quadt, A; Uijterwaal, H; Walczak, R; Wilson, F F; Yip, T; Abbiendi, G; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; De Giorgi, M; Dosselli, U; Limentani, S; Morandin, M; Posocco, M; Stanco, L; Stroili, R; Voci, C; Bulmahn, J; Butterworth, J M; Feild, R G; Whitmore, J; D'Agostini, Giulio; Marini, G; Nigro, A; Tassi, E; Hart, J C; McCubbin, N A; Prytz, K; Shah, T P; Short, T L; Barberis, E; Dubbs, T; Heusch, C A; Van Hook, M; Hubbard, B; Lockman, W; Rahn, J T; Sadrozinski, H F W; Seiden, A; Biltzinger, J; Seifert, R J; Walenta, Albert H; Zech, G; Abramowicz, H; Briskin, G M; Dagan, S; Levy, A; Hasegawa, T; Hazumi, M; Ishii, T; Kuze, M; Mine, S; Nagasawa, Y; Nakao, M; Susuki, I; Tokushuku, K; Yamada, S; Yamazaki, Y; Chiba, M; Hamatsu, R; Hirose, T; Homma, K; Kitamura, S; Nakamitsu, Y; Yamauchi, K; Cirio, R; Costa, M; Ferrero, M I; Lamberti, L; Maselli, S; Peroni, C; Sacchi, R; Solano, A; Staiano, A; Dardo, M; Bailey, D C; Bandyopadhyay, D; Bénard, F; Brkic, M; Crombie, M B; Gingrich, D M; Hartner, G F; Joo, K K; Levman, G M; Martin, J F; Orr, R S; Sampson, C R; Teuscher, R; Catterall, C D; Jones, T W; Kaziewicz, P B; Lane, J B; Saunders, R L; Shulman, J; Blankenship, K; Lu, B; Mo, L W; Bogusz, W; Charchula, K; Ciborowski, J; Gajewski, J; Grzelak, G; Kasprzak, M; Krzyzanowski, M; Muchorowski, K; Nowak, R J; Pawlak, J M; Tymieniecka, T; Wróblewski, A K; Zakrzewski, J A; Zarnecki, A F; Adamus, M; Eisenberg, Y; Karshon, U; Revel, D; Zer-Zion, D; Ali, I; Badgett, W F; Behrens, B H; Dasu, S; Fordham, C; Foudas, C; Goussiou, A; Loveless, R J; Reeder, D D; Silverstein, S; Smith, W H; Vaiciulis, A W; Wodarczyk, M; Tsurugai, T; Bhadra, S; Cardy, M L; Fagerstroem, C P; Frisken, W R; Furutani, K M; Khakzad, M; Schmidke, W B

    1995-01-01

    Inclusive transverse momentum spectra of charged particles in photoproduction events in the laboratory pseudorapidity range -1.2<\\eta<1.4 have been measured up to p_{T}=8\\GeV using the ZEUS detector. Diffractive and non--diffractive reactions have been selected with an average \\gamma p centre of mass (c.m.) energy of \\langle W \\rangle = 180\\GeV. For diffractive reactions, the p_{T} spectra of the photon dissociation events have been measured in two intervals of the dissociated photon mass with mean values \\langle M_{X} \\rangle = 5 GeV and 10 GeV. The inclusive transverse momentum spectra fall exponentially in the low p_{T} region. The non--diffractive data show a pronounced high p_{T} tail departing from the exponential shape. The p_{T} distributions are compared to lower energy photoproduction data and to hadron--hadron collisions at a similar c.m. energy. The data are also compared to the results of a next--to--leading order QCD calculation.

  20. Nonlinear Evolution of Ferroelectric Domains

    Institute of Scientific and Technical Information of China (English)

    WeiLU; Dai-NingFANG; 等

    1997-01-01

    The nonlinear evolution of ferroelectric domains is investigated in the paper and amodel is proposed which can be applied to numerical computation.Numerical results show that the model can accurately predict some nonlinear behavior and consist with those experimental results.