WorldWideScience

Sample records for optical diffraction radiation

  1. Phase control effects in optical diffraction radiation from a slit

    International Nuclear Information System (INIS)

    Castellano, M.; Chiadroni, E.; Cianchi, A.

    2010-01-01

    Optical Diffraction Radiation (ODR) from a slit is becoming a real promising instrument for measuring the transverse beam size, or even the emittance of the very high brightness linacs driving SASE FELs or the future ILC which require non-intercepting diagnostic devices. But to correctly explain experimental data it is necessary to further develop the theory of this radiation emission. In this paper we discuss in particular the effects of a non-perfect coplanarity of the two halves of a slit, that introduces a phase difference in the field produced by the two half-planes. Such non-coplanarity can result from mechanical stress for instance.

  2. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chuyu [Peking Univ., Beijing (China)

    2012-12-31

    difficulty of diagnostics. For most cases, intercepting measurements are no longer acceptable, and nonintercepting method like synchrotron radiation monitor can not be applied to linear accelerators. The development of accelerator technology asks for simutanous diagnostics innovations, to expand the performance of diagnostic tools to meet the requirements of the next generation accelerators. Diffraction radiation and inverse Compton scattering are two of the most promising techniques, their nonintercepting nature avoids perturbance to the beam and damage to the instrumentation. This thesis is divided into two parts, beam size measurement by optical diffraction radiation and Laser system for Compton polarimeter. Diffraction radiation, produced by the interaction between the electric field of charged particles and the target, is related to transition radiation. Even though the theory of diffraction radiation has been discussed since 1960s, there are only a few experimental studies in recent years. The successful beam size measurement by optical diffraction radiation at CEBAF machine is a milestone: First of all, we have successfully demonstrated diffraction radiation as an effective nonintercepting diagnostics; Secondly, the simple linear relationship between the diffraction radiation image size and the actual beam size improves the reliability of ODR measurements; And, we measured the polarized components of diffraction radiation for the first time and I analyzed the contribution from edge radiation to diffraction radiation.

  3. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    International Nuclear Information System (INIS)

    Liu, Chuyu

    2012-01-01

    difficulty of diagnostics. For most cases, intercepting measurements are no longer acceptable, and nonintercepting method like synchrotron radiation monitor can not be applied to linear accelerators. The development of accelerator technology asks for simutanous diagnostics innovations, to expand the performance of diagnostic tools to meet the requirements of the next generation accelerators. Diffraction radiation and inverse Compton scattering are two of the most promising techniques, their nonintercepting nature avoids perturbance to the beam and damage to the instrumentation. This thesis is divided into two parts, beam size measurement by optical diffraction radiation and Laser system for Compton polarimeter. Diffraction radiation, produced by the interaction between the electric field of charged particles and the target, is related to transition radiation. Even though the theory of diffraction radiation has been discussed since 1960s, there are only a few experimental studies in recent years. The successful beam size measurement by optical diffraction radiation at CEBAF machine is a milestone: First of all, we have successfully demonstrated diffraction radiation as an effective nonintercepting diagnostics; Secondly, the simple linear relationship between the diffraction radiation image size and the actual beam size improves the reliability of ODR measurements; And, we measured the polarized components of diffraction radiation for the first time and I analyzed the contribution from edge radiation to diffraction radiation

  4. 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

  5. Diffractive optics for industrial and commercial applications

    Energy Technology Data Exchange (ETDEWEB)

    Turunen, J. [Joensuu Univ. (Finland); Wyrowski, F. [eds.] [Jena Univ. (Germany)

    1997-12-31

    The following topics were dealt with: diffractive optics, diffraction gratings, optical system design with diffractive optics, continuous-relief diffractive lenses and microlens arrays, diffractive bifocal intraocular lenses, diffractive laser resonators, diffractive optics for semiconductor lasers, diffractive elements for optical image processing, photorefractive crystals in optical measurement systems, subwavelenth-structured elements, security applications, diffractive optics for solar cells, holographic microlithography. 999 refs.

  6. 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...

  7. New optical scheme for differential measurements of diffraction reflection intensity on X-radiation sliding incidence

    International Nuclear Information System (INIS)

    Golovin, A.L.; Mas', E.T.

    1989-01-01

    An X-ray optical scheme for differential measurements of X-ray diffraction under sliding incidence conditions is proposed and an attachment design realizng this scheme, using standard equipment, is described. The main feature of the scheme is the following: collimation according to the Bragg angle is carried out for the reflected beam rather than the incident one. Goniometers can be used from DRON, TRS, GS-5 and other spectrometers. The goniometer head carrying the sample is standard, it is a part of the DRON, TRS and DTS. The crystal analyzer is fixed on the attachment. The angular position of the crystal monochromator is controlled by an inductive sensor. The experimental differential curves of X-ray diffraction under conditions of sliding incidence, taken for a silicon crystal having the 111 orientation, are given as well

  8. X-ray-excited optical luminescence of protein crystals: a new tool for studying radiation damage during diffraction data collection.

    Science.gov (United States)

    Owen, Robin L; Yorke, Briony A; Pearson, Arwen R

    2012-05-01

    During X-ray irradiation protein crystals radiate energy in the form of small amounts of visible light. This is known as X-ray-excited optical luminescence (XEOL). The XEOL of several proteins and their constituent amino acids has been characterized using the microspectrophotometers at the Swiss Light Source and Diamond Light Source. XEOL arises primarily from aromatic amino acids, but the effects of local environment and quenching within a crystal mean that the XEOL spectrum of a crystal is not the simple sum of the spectra of its constituent parts. Upon repeated exposure to X-rays XEOL spectra decay non-uniformly, suggesting that XEOL is sensitive to site-specific radiation damage. However, rates of XEOL decay were found not to correlate to decays in diffracting power, making XEOL of limited use as a metric for radiation damage to protein crystals. © 2012 International Union of Crystallography

  9. Diffraction radiation from relativistic particles

    CERN Document Server

    Potylitsyn, Alexander Petrovich; Strikhanov, Mikhail Nikolaevich; Tishchenko, Alexey Alexandrovich

    2010-01-01

    This book deals with diffraction radiation, which implies the boundary problems of electromagnetic radiation theory. Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Diffraction radiation of non-relativistic particles is widely used to design intense emitters in the cm wavelength range. Diffraction radiation from relativistic charged particles is important for noninvasive beam diagnostics and design of free electron lasers based on Smith-Purcell radiation which is diffraction radiation from periodic structures. Different analytical models of diffraction radiation and results of recent experimental studies are presented in this book. The book may also serve as guide to classical electrodynamics applications in beam physics and electrodynamics. It can be of great use for young researchers to develop skills and for experienced scientists to obtain new results.

  10. Diffraction radiation from relativistic particles

    International Nuclear Information System (INIS)

    Potylitsyn, Alexander Petrovich; Ryazanov, Mikhail Ivanovich; Strikhanov, Mikhail Nikolaevich; Tishchenko, Alexey Alexandrovich

    2010-01-01

    This book deals with diffraction radiation, which implies the boundary problems of electromagnetic radiation theory. Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Diffraction radiation of non-relativistic particles is widely used to design intense emitters in the cm wavelength range. Diffraction radiation from relativistic charged particles is important for noninvasive beam diagnostics and design of free electron lasers based on Smith-Purcell radiation which is diffraction radiation from periodic structures. Different analytical models of diffraction radiation and results of recent experimental studies are presented in this book. The book may also serve as guide to classical electrodynamics applications in beam physics and electrodynamics. It can be of great use for young researchers to develop skills and for experienced scientists to obtain new results. (orig.)

  11. Study of optical Laue diffraction

    International Nuclear Information System (INIS)

    Chakravarthy, Giridhar; Allam, Srinivasa Rao; Satyanarayana, S. V. M.; Sharan, Alok

    2014-01-01

    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

  12. 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.

  13. Diffractive nonimaging optics

    NARCIS (Netherlands)

    Jong, de T.M.

    2012-01-01

    Economic use of energy often depends on efficient management of light. Power generation from solar energy, for example, can involve optical systems that concentrate incident sunlight onto a small area and thereby reduce the required surface area of photovoltaic elements. Similarly, efficient

  14. Digital diffractive optics: Have diffractive optics entered mainstream industry yet?

    Science.gov (United States)

    Kress, Bernard; Hejmadi, Vic

    2010-05-01

    When a new technology is integrated into industry commodity products and consumer electronic devices, and sold worldwide in retail stores, it is usually understood that this technology has then entered the realm of mainstream technology and therefore mainstream industry. Such a leap however does not come cheap, as it has a double edge sword effect: first it becomes democratized and thus massively developed by numerous companies for various applications, but also it becomes a commodity, and thus gets under tremendous pressure to cut down its production and integration costs while not sacrificing to performance. We will show, based on numerous examples extracted from recent industry history, that the field of Diffractive Optics is about to undergo such a major transformation. Such a move has many impacts on all facets of digital diffractive optics technology, from the optical design houses to the micro-optics foundries (for both mastering and volume replication), to the final product integrators or contract manufacturers. The main causes of such a transformation are, as they have been for many other technologies in industry, successive technological bubbles which have carried and lifted up diffractive optics technology within the last decades. These various technological bubbles have been triggered either by real industry needs or by virtual investment hype. Both of these causes will be discussed in the paper. The adjective ""digital"" in "digital diffractive optics" does not refer only, as it is done in digital electronics, to the digital functionality of the element (digital signal processing), but rather to the digital way they are designed (by a digital computer) and fabricated (as wafer level optics using digital masking techniques). However, we can still trace a very strong similarity between the emergence of micro-electronics from analog electronics half a century ago, and the emergence of digital optics from conventional optics today.

  15. Observation of coherent optical phonons excited by femtosecond laser radiation in Sb films by ultrafast electron diffraction method

    Energy Technology Data Exchange (ETDEWEB)

    Mironov, B. N.; Kompanets, V. O.; Aseev, S. A., E-mail: isanfemto@yandex.ru [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation); Ischenko, A. A. [Moscow Technological University, Institute of High Chemical Technologies (Russian Federation); Kochikov, I. V. [Moscow State University (Russian Federation); Misochko, O. V. [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation); Chekalin, S. V.; Ryabov, E. A. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation)

    2017-03-15

    The generation of coherent optical phonons in a polycrystalline antimony film sample has been investigated using femtosecond electron diffraction method. Phonon vibrations have been induced in the Sb sample by the main harmonic of a femtosecond Ti:Sa laser (λ = 800 nm) and probed by a pulsed ultrashort photoelectron beam synchronized with the pump laser. The diffraction patterns recorded at different times relative to the pump laser pulse display oscillations of electron diffraction intensity corresponding to the frequencies of vibrations of optical phonons: totally symmetric (A{sub 1g}) and twofold degenerate (E{sub g}) phonon modes. The frequencies that correspond to combinations of these phonon modes in the Sb sample have also been experimentally observed.

  16. Electro-optic diffraction grating tuned laser

    International Nuclear Information System (INIS)

    Hughes, R.S.

    1975-01-01

    An electro-optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro-optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating is described. An optional angle multiplier may be used between the electro-optic diffraction grating and the reflective grating. (auth)

  17. Diffractive optical elements for space communication terminals

    OpenAIRE

    Herzig, Hans-Peter; Ehbets, Peter; Teijido, Juan M.; Weible, Kenneth J.; Heimbeck, Hans-Joerg

    2007-01-01

    The potential of diffractive optical elements for advanced laser communication terminals has been investigated. Applications include beam shaping of high- power laser diode arrays, optical filter elements for position detection and hybrid (refractive/diffractive) elements. In addition, we present a design example of a miniaturized terminal including diffractive optics.

  18. Non-diffractive optically variable security devices

    NARCIS (Netherlands)

    Renesse, R.L. van

    1991-01-01

    At the past optical security conferences attention was focused on diffractive structures, e.g. holograms, embossed gratings and thin—film devices, as security elements on valuable documents. The main reasons for this emphasis are, that the iridescent effect of such diffractive optically variable

  19. 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.

  20. Propagation and diffraction of optical vortices

    International Nuclear Information System (INIS)

    Fischer, Pascal; Skelton, Susan E.; Leburn, Christopher G.; Streuber, Casey T.; Wright, Ewan M.; Dholakia, Kishan

    2008-01-01

    We explore the propagation and diffraction of optical vortices (Laguerre-Gaussian beams) of varying azimuthal index past a circular obstacle and Young's double slits. When the beam and obstacle centers are aligned the famous spot of Arago, which arises for zero azimuthal index, is replaced for non-zero azimuthal indices by a dark spot of Arago, a simple consequence of the conserved phase singularity at the beam center. We explore how for larger azimuthal indices, as the beam and obstacle centers are progressively misaligned, the central dark spot breaks up into several dark spots of Arago. Using Young's double slits we can easily measure the azimuthal index of the vortex beam, even for polychromatic vortices generated by broadband supercontinuum radiation

  1. Diffractive optics: design, fabrication, and test

    National Research Council Canada - National Science Library

    O'Shea, Donald C

    2004-01-01

    This book provides the reader with the broad range of materials that were discussed in a series of short courses presented at Georgia Tech on the design, fabrication, and testing of diffractive optical elements (DOEs...

  2. Diffraction of radiation from channelled charged particles

    International Nuclear Information System (INIS)

    Baryshevskij, V.G.; Grubich, A.O.; Dubovskaya, I.Ya.

    1978-01-01

    An explicit expression for cross-section and radiation spectrum at diffraction is calculated. It is shown that photons emitted by channelled particles form a typical diffraction pattern which contains information about the crystal structure. It is also shown that the change of the longitudinal energy of the particle caused by the radiation braking becomes important when the particle energy is increased. (author)

  3. Gluon radiation in diffractive electroproduction

    International Nuclear Information System (INIS)

    Buchmueller, W.; McDermott, M.F.; Hebecker, A.

    1996-07-01

    Order α s -correlations to the diffractive structure functions F L D and F 2 D at large Q 2 and small x are evaluated in the semiclassical approach, where the initial proton is treated as a classical colour field. The diffractive final state contains a fast gluon in addition to a quark-antiquark pair. Two of these partons may have large transverse momentum. Our calculations lead to an intuitive picture of deep-inelastic diffractive processes which is very similar to Bjorken's aligned-jet model. Both diffractive structure functions contain leading twist contributions from high-p perpendicular to jets. (orig.)

  4. Tolerance analysis on diffraction efficiency and polychromatic integral diffraction efficiency for harmonic diffractive optics

    Science.gov (United States)

    Shan, Mao

    2016-10-01

    In this dissertation, the mathematical model of effect of manufacturing errors including microstructure relative height error and relative width error on diffraction efficiency for the harmonic diffractive optical elements (HDEs) is set up. According to the expression of the phase delay and diffraction efficiency of the HDEs, the expression of diffraction efficiency of refraction and diffractive optical element with the microstructure height and periodic width errors in fabrication process is presented in this paper. Furthermore, the effect of manufacturing errors on diffraction efficiency for the harmonic diffractive optical elements is studied, and diffraction efficiency change is analyzed as the relative microstructure height-error in the same and in the opposite sign as well as relative width-error in the same and in the opposite sign. Example including infrared wavelength with materials GE has been discussed in this paper. Two kinds of manufacturing errors applied in 3.7 4.3um middle infrared and 8.7-11.5um far infrared optical system which results in diffraction efficiency and PIDE of HDEs are studied. The analysis results can be used for manufacturing error control in micro-structure height and periodic width. Results can be used for HDEs processing.

  5. Geometrical optics and the diffraction phenomenon

    International Nuclear Information System (INIS)

    Timofeev, Aleksandr V

    2005-01-01

    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)

  6. Bragg diffraction of fermions at optical potentials

    International Nuclear Information System (INIS)

    Deh, Benjamin

    2008-01-01

    This thesis describes the Bragg diffraction of ultracold fermions at an optical potential. A moving optical lattice was created, by overlaying two slightly detuned lasers. Atoms can be diffracted at this lattice if the detuning fulfills the Bragg condition for resting atoms. This Bragg diffraction is analyzed systematically in this thesis. To this end Rabi oscillations between the diffraction states were driven, as well in the weakly interacting Bragg regime, as in the strongly interacting Kapitza-Dirac regime. Simulations, based on a driven two-, respectively multilevel-system describe the observed effects rather well. Furthermore, the temporal evolution of the diffracted states in the magnetic trapping potential was studied. The anharmonicity of the trap in use and the scattering cross section for p-wave collisions in a 6 Li system was determined from the movement of these states. Moreover the momentum distribution of the fermions was measured with Bragg spectroscopy and first signs of Fermi degeneracy were found. Finally an interferometer with fermions was build, exhibiting a coherence time of more than 100 μs. With this, the possibility for measurement and manipulation of ultracold fermions with Bragg diffraction could bee shown. (orig.)

  7. Surface diffusion studies by optical diffraction techniques

    International Nuclear Information System (INIS)

    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

  8. Nuclear Bragg diffraction using synchrotron radiation

    International Nuclear Information System (INIS)

    Rueffer, R.; Gerdau, E.; Grote, M.; Hollatz, R.; Roehlsberger, R.; Rueter, H.D.; Sturhahn, W.

    1990-01-01

    Nuclear Bragg diffraction with synchrotron radiation as source will become a powerful new X-ray source in the A-region. This source exceeds by now the brilliance of conventional Moessbauer sources giving hyperfine spectroscopy further momentum. As examples applications to yttrium iron garnet (YIG) and iron borate will be discussed. (author)

  9. Diffractive interference optical analyzer (DiOPTER)

    Science.gov (United States)

    Sasikumar, Harish; Prasad, Vishnu; Pal, Parama; Varma, Manoj M.

    2016-03-01

    This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6x10-7 RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4x10-4 RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products.

  10. Imaging spectroscopy using embedded diffractive optical arrays

    Science.gov (United States)

    Hinnrichs, Michele; Hinnrichs, Bradford

    2017-09-01

    Pacific Advanced Technology (PAT) has developed an infrared hyperspectral camera based on diffractive optic arrays. This approach to hyperspectral imaging has been demonstrated in all three infrared bands SWIR, MWIR and LWIR. The hyperspectral optical system has been integrated into the cold-shield of the sensor enabling the small size and weight of this infrared hyperspectral sensor. This new and innovative approach to an infrared hyperspectral imaging spectrometer uses micro-optics that are made up of an area array of diffractive optical elements where each element is tuned to image a different spectral region on a common focal plane array. The lenslet array is embedded in the cold-shield of the sensor and actuated with a miniature piezo-electric motor. This approach enables rapid infrared spectral imaging with multiple spectral images collected and processed simultaneously each frame of the camera. This paper will present our optical mechanical design approach which results in an infrared hyper-spectral imaging system that is small enough for a payload on a small satellite, mini-UAV, commercial quadcopter or man portable. Also, an application of how this spectral imaging technology can easily be used to quantify the mass and volume flow rates of hydrocarbon gases. The diffractive optical elements used in the lenslet array are blazed gratings where each lenslet is tuned for a different spectral bandpass. The lenslets are configured in an area array placed a few millimeters above the focal plane and embedded in the cold-shield to reduce the background signal normally associated with the optics. The detector array is divided into sub-images covered by each lenslet. We have developed various systems using a different number of lenslets in the area array. Depending on the size of the focal plane and the diameter of the lenslet array will determine the number of simultaneous different spectral images collected each frame of the camera. A 2 x 2 lenslet array will image

  11. Diffractive optical elements written by photodeposition

    International Nuclear Information System (INIS)

    Baal-Zedaka, I.; Hava, S.; Mirchin, N.; Margolin, R.; Zagon, M.; Lapsker, I.; Azoulay, J.; Peled, A.

    2003-01-01

    In this work direct laser writing of diffractive optical elements (DOE) by photodeposition (PD) of amorphous selenium (a-Se) from colloid solutions has been investigated. We used a computer controlled laser scanner for patterning thin film micro-profiles creating thus planar optical elements by direct beam writing on surfaces immersed in a liquid phase PD cell. The laser employed was an argon ion laser at 488 nm wavelength, with powers up to 55 mW, for writing typically 25-250 μm wide lines of 200 nm thickness at rates of about 150 μm/s. Various elements made of photodeposited thin films on polymethyl-methacrylate (PMMA) substrates were produced for prototyping microlenses, linear grating arrays, cylindrical and circular profiled DOE patterns

  12. Transition radiation and diffraction radiation. Similarities and differences

    International Nuclear Information System (INIS)

    Potylitsyn, A.P.

    1998-01-01

    The characteristics of diffraction radiation (DR), i.e. radiation of the charged particle moving near conducting target have been considered for an ultrarelativistic case. The simple expressions for DR fields for the semi-infinite ideal conducting target have been derived. The close connection between transition radiation (TR) and DR has been shown. The effect of finite transversal sizes of target on TR characteristics has been evaluated. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  13. Light distribution in diffractive multifocal optics and its optimization.

    Science.gov (United States)

    Portney, Valdemar

    2011-11-01

    To expand a geometrical model of diffraction efficiency and its interpretation to the multifocal optic and to introduce formulas for analysis of far and near light distribution and their application to multifocal intraocular lenses (IOLs) and to diffraction efficiency optimization. Medical device consulting firm, Newport Coast, California, USA. Experimental study. Application of a geometrical model to the kinoform (single focus diffractive optical element) was expanded to a multifocal optic to produce analytical definitions of light split between far and near images and light loss to other diffraction orders. The geometrical model gave a simple interpretation of light split in a diffractive multifocal IOL. An analytical definition of light split between far, near, and light loss was introduced as curve fitting formulas. Several examples of application to common multifocal diffractive IOLs were developed; for example, to light-split change with wavelength. The analytical definition of diffraction efficiency may assist in optimization of multifocal diffractive optics that minimize light loss. Formulas for analysis of light split between different foci of multifocal diffractive IOLs are useful in interpreting diffraction efficiency dependence on physical characteristics, such as blaze heights of the diffractive grooves and wavelength of light, as well as for optimizing multifocal diffractive optics. Disclosure is found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  14. Optical system storage design with diffractive optical elements

    Science.gov (United States)

    Kostuk, Raymond K.; Haggans, Charles W.

    1993-01-01

    Optical data storage systems are gaining widespread acceptance due to their high areal density and the ability to remove the high capacity hard disk from the system. In magneto-optical read-write systems, a small rotation of the polarization state in the return signal from the MO media is the signal which must be sensed. A typical arrangement used for detecting these signals and correcting for errors in tracking and focusing on the disk is illustrated. The components required to achieve these functions are listed. The assembly and alignment of this complex system has a direct impact on cost, and also affects the size, weight, and corresponding data access rates. As a result, integrating these optical components and improving packaging techniques is an active area of research and development. Most designs of binary optic elements have been concerned with optimizing grating efficiency. However, rigorous coupled wave models for vector field diffraction from grating surfaces can be extended to determine the phase and polarization state of the diffracted field, and the design of polarization components. A typical grating geometry and the phase and polarization angles associated with the incident and diffracted fields are shown. In our current stage of work, we are examining system configurations which cascade several polarization functions on a single substrate. In this design, the beam returning from the MO disk illuminates a cascaded grating element which first couples light into the substrate, then introduces a quarter wave retardation, then a polarization rotation, and finally separates s- and p-polarized fields through a polarization beam splitter. The input coupler and polarization beam splitter are formed in volume gratings, and the two intermediate elements are zero-order elements.

  15. Nuclear dynamical diffraction using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Dennis Eugene [Stanford Univ., CA (United States)

    1993-05-01

    The scattering of synchrotron radiation by nuclei is extensively explored in this thesis. From the multipole electric field expansion resulting from time-dependent nonrelativistic perturbation theory, a dynamical scattering theory is constructed. This theory is shown, in the many particle limit, to be equivalent to the semi-classical approach where a quantum mechanical scattering amplitude is used in the Maxwell inhomogeneous wave equation. The Moessbauer specimen whose low-lying energy levels were probed is a ferromagnetic lattice of 57Fe embedded in a yttrium iron garnet (YIG) crystal matrix. The hyperfine fields in YIG thin films were studied at low and room temperature using time-resolved quantum beat spectroscopy. Nuclear hyperfine structure quantum beats were measured using a fast plastic scintillator coincidence photodetector and associated electronics having a time resolution of 2.5 nsec. The variation of the quantum beat patterns near the Bragg [0 0 2] diffraction peak gave a Lamb-Moessbauer factor of 8.2±0.4. Exploring characteristic dynamical features in the higher order YIG [0 0 10] reflection revealed that one of the YIG crystals had bifurcated into two different layers. The dynamics of nuclear superradiance was explored. This phenomenon includes the radiative speedup exhibited by a collective state of particles, and, in striking concurrence, resonance frequency shifts. A speedup of a factor of 4 in the total decay rate and a beat frequency shift of 11/2 natural resonance linewidths were observed. Nuclear resonance scattering was also found to be a useful way of performing angular interferometry experiments, and it was used to observe the phase shift of a rotated quantum state. On the whole, nuclear dynamical diffraction theory has superbly explained many of the fascinating features of resonant magnetic dipole radiation scattered by a lattice of nuclei.

  16. Nuclear dynamical diffraction using synchrotron radiation

    International Nuclear Information System (INIS)

    Brown, D.E.

    1993-05-01

    The scattering of synchrotron radiation by nuclei is extensively explored in this thesis. From the multipole electric field expansion resulting from time-dependent nonrelativistic perturbation theory, a dynamical scattering theory is constructed. This theory is shown, in the many particle limit, to be equivalent to the semi-classical approach where a quantum mechanical scattering amplitude is used in the Maxwell inhomogeneous wave equation. The Moessbauer specimen whose low-lying energy levels were probed is a ferromagnetic lattice of 57 Fe embedded in a yttrium iron garnet (YIG) crystal matrix. The hyperfine fields in YIG thin films were studied at low and room temperature using time-resolved quantum beat spectroscopy. Nuclear hyperfine structure quantum beats were measured using a fast plastic scintillator coincidence photodetector and associated electronics having a time resolution of 2.5 nsec. The variation of the quantum beat patterns near the Bragg [0 0 2] diffraction peak gave a Lamb-Moessbauer factor of 8.2±0.4. Exploring characteristic dynamical features in the higher order YIG [0 0 10] reflection revealed that one of the YIG crystals had bifurcated into two different layers. The dynamics of nuclear superradiance was explored. This phenomenon includes the radiative speedup exhibited by a collective state of particles, and, in striking concurrence, resonance frequency shifts. A speedup of a factor of 4 in the total decay rate and a beat frequency shift of 1 1/2 natural resonance linewidths were observed. Nuclear resonance scattering was also found to be a useful way of performing angular interferometry experiments, and it was used to observe the phase shift of a rotated quantum state. On the whole, nuclear dynamical diffraction theory has superbly explained many of the fascinating features of resonant magnetic dipole radiation scattered by a lattice of nuclei

  17. Computer controlling of writing beam in laser microfabrication of diffractive optics

    OpenAIRE

    Korolkov, V.; Shimansky, R.; Cherkashin, V.; Denk, D.

    2003-01-01

    Laser microfabrication of diffractive optics with continuous relief is based on the direct local action of focused laser radiation on the recording material. Control of writing beam parameters (beam power, spot size, waist position) is one of the main tasks in microfabrication using laser writing systems. Method of the control defines the correspondence between the fabricated microrelief of the diffractive optical element and a designed one. Complexity of this task consists in the necessity t...

  18. An amplitude and phase hybrid modulation Fresnel diffractive optical element

    Science.gov (United States)

    Li, Fei; Cheng, Jiangao; Wang, Mengyu; Jin, Xueying; Wang, Keyi

    2018-04-01

    An Amplitude and Phase Hybrid Modulation Fresnel Diffractive Optical Element (APHMFDOE) is proposed here. We have studied the theory of APHMFDOE and simulated the focusing properties of it along the optical axis, which show that the focus can be blazed to other positions with changing the quadratic phase factor. Moreover, we design a Composite Fresnel Diffraction Optical Element (CFDOE) based on the characteristics of APHMFDOE. It greatly increases the outermost zone width without changing the F-number, which brings a lot of benefits to the design and processing of diffraction device. More importantly, the diffraction efficiency of the CFDOE is almost unchanged compared with AFZP at the same focus.

  19. A pseudospectral collocation time-domain method for diffractive optics

    DEFF Research Database (Denmark)

    Dinesen, P.G.; Hesthaven, J.S.; Lynov, Jens-Peter

    2000-01-01

    We present a pseudospectral method for the analysis of diffractive optical elements. The method computes a direct time-domain solution of Maxwell's equations and is applied to solving wave propagation in 2D diffractive optical elements. (C) 2000 IMACS. Published by Elsevier Science B.V. All rights...

  20. Diffractive optical elements for transformation of modes in lasers

    Science.gov (United States)

    Sridharan, Arun K.; Pax, Paul H.; Heebner, John E.; Drachenberg, Derrek R.; Armstrong, James P.; Dawson, Jay W.

    2015-09-01

    Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

  1. Computational imaging using lightweight diffractive-refractive optics

    KAUST Repository

    Peng, Yifan

    2015-11-23

    Diffractive optical elements (DOE) show great promise for imaging optics that are thinner and more lightweight than conventional refractive lenses while preserving their light efficiency. Unfortunately, severe spectral dispersion currently limits the use of DOEs in consumer-level lens design. In this article, we jointly design lightweight diffractive-refractive optics and post-processing algorithms to enable imaging under white light illumination. Using the Fresnel lens as a general platform, we show three phase-plate designs, including a super-thin stacked plate design, a diffractive-refractive-hybrid lens, and a phase coded-aperture lens. Combined with cross-channel deconvolution algorithm, both spherical and chromatic aberrations are corrected. Experimental results indicate that using our computational imaging approach, diffractive-refractive optics is an alternative candidate to build light efficient and thin optics for white light imaging.

  2. Computational imaging using lightweight diffractive-refractive optics

    KAUST Repository

    Peng, Yifan; Fu, Qiang; Amata, Hadi; Su, Shuochen; Heide, Felix; Heidrich, Wolfgang

    2015-01-01

    Diffractive optical elements (DOE) show great promise for imaging optics that are thinner and more lightweight than conventional refractive lenses while preserving their light efficiency. Unfortunately, severe spectral dispersion currently limits the use of DOEs in consumer-level lens design. In this article, we jointly design lightweight diffractive-refractive optics and post-processing algorithms to enable imaging under white light illumination. Using the Fresnel lens as a general platform, we show three phase-plate designs, including a super-thin stacked plate design, a diffractive-refractive-hybrid lens, and a phase coded-aperture lens. Combined with cross-channel deconvolution algorithm, both spherical and chromatic aberrations are corrected. Experimental results indicate that using our computational imaging approach, diffractive-refractive optics is an alternative candidate to build light efficient and thin optics for white light imaging.

  3. Radiation optic neuropathy

    International Nuclear Information System (INIS)

    Kline, L.B.; Kim, J.Y.; Ceballos, R.

    1985-01-01

    Following surgery for pituitary adenoma, radiation therapy is an accepted treatment in reducing tumor recurrence. However, a potential therapeutic complication is delayed radionecrosis of perisellar neural structures, including the optic nerves and chiasm. This particular cause of visual loss, radiation optic neuropathy (RON), has not been emphasized in the ophthalmologic literature. Four cases of RON seen in the past five years are reported. Diagnostic criteria include: (1) acute visual loss (monocular or binocular), (2) visual field defects indicating optic nerve or chiasmal dysfunction, (3) absence of optic disc edema, (4) onset usually within three years of therapy (peak: 1-1 1/2 years), and (5) no computed tomographic evidence of visual pathway compression. Pathologic findings, differential diagnosis and therapy will be discussed in outlining the clinical profile of RON

  4. Refractive and diffractive neutron optics with reduced chromatic aberration

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Poulsen, Henning Friis; Bentley, P.M.

    2014-01-01

    by the use of optics for focusing and imaging. Refractive and diffractive optical elements, e.g. compound refractive lenses and Fresnel zone plates, are attractive due to their low cost, and simple alignment. These optical elements, however, suffer from chromatic aberration, which limit their effectiveness...

  5. Encoded diffractive optics for full-spectrum computational imaging

    KAUST Repository

    Heide, Felix

    2016-09-16

    Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. However, such elements introduce severe chromatic aberrations and are not variable, unless used in combination with other elements in a larger, reconfigurable optical system. We introduce numerically optimized encoded phase masks in which different optical parameters such as focus or zoom can be accessed through changes in the mechanical alignment of a ultra-thin stack of two or more masks. Our encoded diffractive designs are combined with a new computational approach for self-calibrating imaging (blind deconvolution) that can restore high-quality images several orders of magnitude faster than the state of the art without pre-calibration of the optical system. This co-design of optics and computation enables tunable, full-spectrum imaging using thin diffractive optics.

  6. Encoded diffractive optics for full-spectrum computational imaging

    KAUST Repository

    Heide, Felix; Fu, Qiang; Peng, Yifan; Heidrich, Wolfgang

    2016-01-01

    Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. However, such elements introduce severe chromatic aberrations and are not variable, unless used in combination with other elements in a larger, reconfigurable optical system. We introduce numerically optimized encoded phase masks in which different optical parameters such as focus or zoom can be accessed through changes in the mechanical alignment of a ultra-thin stack of two or more masks. Our encoded diffractive designs are combined with a new computational approach for self-calibrating imaging (blind deconvolution) that can restore high-quality images several orders of magnitude faster than the state of the art without pre-calibration of the optical system. This co-design of optics and computation enables tunable, full-spectrum imaging using thin diffractive optics.

  7. Optical diffraction from fractals with a structural transition

    International Nuclear Information System (INIS)

    Perez Rodriguez, F.; Canessa, E.

    1994-04-01

    A macroscopic characterization of fractals showing up a structural transition from dense to multibranched growth is made using optical diffraction theory. Such fractals are generated via the numerical solution of the 2D Poisson and biharmonic equations and are compared to more 'regular' irreversible clusters such as diffusion limited and Laplacian aggregates. The optical diffraction method enables to identify a decrease of the fractal dimension above the structural point. (author). 19 refs, 6 figs

  8. Spatiotemporal optical pulse transformation by a resonant diffraction grating

    Energy Technology Data Exchange (ETDEWEB)

    Golovastikov, N. V.; Bykov, D. A., E-mail: bykovd@gmail.com; Doskolovich, L. L., E-mail: leonid@smr.ru; Soifer, V. A. [Russian Academy of Sciences, Image Processing Systems Institute (Russian Federation)

    2015-11-15

    The diffraction of a spatiotemporal optical pulse by a resonant diffraction grating is considered. The pulse diffraction is described in terms of the signal (the spatiotemporal incident pulse envelope) passage through a linear system. An analytic approximation in the form of a rational function of two variables corresponding to the angular and spatial frequencies has been obtained for the transfer function of the system. A hyperbolic partial differential equation describing the general form of the incident pulse envelope transformation upon diffraction by a resonant diffraction grating has been derived from the transfer function. A solution of this equation has been obtained for the case of normal incidence of a pulse with a central frequency lying near the guided-mode resonance of a diffraction structure. The presented results of numerical simulations of pulse diffraction by a resonant grating show profound changes in the pulse envelope shape that closely correspond to the proposed theoretical description. The results of the paper can be applied in creating new devices for optical pulse shape transformation, in optical information processing problems, and analog optical computations.

  9. Dedicated software for diffractive optics design and simulation

    International Nuclear Information System (INIS)

    Firsov, A; Brzhezinskaya, M; Erko, A; Firsov, A; Svintsov, A

    2013-01-01

    An efficient software package for the structure design and simulation of imaging properties of diffraction optical elements has been developed. It operates with point source and consists of: the ZON software, to calculate the structure of an optical element in transmission and reflection; the KRGF software, to simulate the diffraction properties of an ideal optical element with point source; the DS software, to calculate the diffraction properties by taking into consideration material and shadowing effects. Optional software allows simulation with a real non-point source. Zone plate thickness profile, source shape as well as substrate curvature are considered in this calculation. This is especially important for the diffractive focusing elements and gratings at a total external reflection, given that the lateral size of the structure can be up to 1 m. The program package can be used in combination with the Nanomaker software to prepare data for ion and e-beam surface modifications and corrections.

  10. Diffractive Optics for Gravitational Wave Detectors

    International Nuclear Information System (INIS)

    Bunkowski, A; Burmeister, O; Clausnitzer, T; Kley, E-B; Tuennermann, A; Danzmann, K; Schnabel, R

    2006-01-01

    All-reflective interferometry based on nano-structured diffraction gratings offers new possibilities for gravitational wave detection. We investigate an all-reflective Fabry-Perot interferometer concept in 2nd order Littrow mount. The input-output relations for such a resonator are derived treating the grating coupler by means of a scattering matrix formalism. A low loss dielectric reflection grating has been designed and manufactured to test the properties of such a grating cavity

  11. Diffractive optical element for creating visual 3D images.

    Science.gov (United States)

    Goncharsky, Alexander; Goncharsky, Anton; Durlevich, Svyatoslav

    2016-05-02

    A method is proposed to compute and synthesize the microrelief of a diffractive optical element to produce a new visual security feature - the vertical 3D/3D switch effect. The security feature consists in the alternation of two 3D color images when the diffractive element is tilted up/down. Optical security elements that produce the new security feature are synthesized using electron-beam technology. Sample optical security elements are manufactured that produce 3D to 3D visual switch effect when illuminated by white light. Photos and video records of the vertical 3D/3D switch effect of real optical elements are presented. The optical elements developed can be replicated using standard equipment employed for manufacturing security holograms. The new optical security feature is easy to control visually, safely protected against counterfeit, and designed to protect banknotes, documents, ID cards, etc.

  12. ADVANTAGES OF DIFFRACTIVE OPTICAL ELEMENTS APPLICATION IN SIMPLE OPTICAL IMAGING SYSTEMS

    Directory of Open Access Journals (Sweden)

    N. D. Zoric

    2015-01-01

    Full Text Available The paper deals with the influence of diffractive optical elements on the optical aberrations. The correction of optical aberrations was investigated in the simple optical systems with one and two lenses (singlet and doublet. The advantages of diffractive optical elements are their ability to generate arbitrary complex wave fronts from a piece of optical material that is essentially flat. The optical systems consisting of the standard surfaces were designed and optimized by using the same starting points. Further, the diffractive and aspheric surfaces were introduced into the developed systems. The resulting hybrid systems were optimized. To compare the complicity of the development of narrow field systems and wide field optical systems, the optimization has been done separately for these two types of the instruments. The optical systems were designed by using special Optical Design Software. Тhe characteristics of designed diffractive surfaces were controlled in Software DIFSYS 2.30. Due to the application of diffractive optical elements the longitudinal chromatic aberration was 5 times reduced for the narrow field systems. The absolute value of Seidel coefficient related to the spherical aberration was reduced in the range of 0.03. Considering that diffractive optical elements have the known disadvantages, like possible parasitic diffraction orders and probable decrease of the transmission, we also developed and analyzed the optical systems with combined aspheric and diffractive surfaces. A combination of the aspheric and diffractive surfaces in the optical disk system of the disk reading lens, gave cutting down of the longitudinal color aberrations almost 15 times on-axis, comparing to the lens consisting of the aspherical and standard surfaces. All of the designed diffractive optical elements possess the parameters within the fabrication limits.

  13. Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation

    Czech Academy of Sciences Publication Activity Database

    Hrdý, Jaromír; Mikulík, P.; Oberta, Peter

    2011-01-01

    Roč. 18, č. 2 (2011), s. 299-301 ISSN 0909-0495 R&D Projects: GA MPO FR-TI1/412 Institutional research plan: CEZ:AV0Z10100522 Keywords : diffractive-refractive optics * x-ray synchrotron radiation monochromator * x-ray crystal monochromator * harmonics separation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.726, year: 2011

  14. Radiation effects in optical components

    International Nuclear Information System (INIS)

    Friebele, E.J.

    1987-01-01

    This report discusses components of high performance optical devices may be exposed to high energy radiation environments during their lifetime. The effect of these adverse environments depends upon a large number of parameters associated with the radiation (nature, energy, dose, dose rate, etc.) or the system (temperature, optical performance requirements, optical wavelength, optical power, path length, etc.), as well as the intrinsic susceptibility of the optical component itself to degradation

  15. Enhanced radiation resistant fiber optics

    International Nuclear Information System (INIS)

    Lyons, P.B.; Looney, L.D.

    1993-01-01

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures

  16. Enhanced radiation resistant fiber optics

    Science.gov (United States)

    Lyons, P.B.; Looney, L.D.

    1993-11-30

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

  17. Optical radiation and visual health

    International Nuclear Information System (INIS)

    Waxler, M.; Hitchins, V.M.

    1986-01-01

    This book provides a focus on the parameters of ultraviolet light, visible, and infrared radiation s which could cause long-term visual health problems in humans. It reviews early research on radiation effects on the eye, and gives detailed attention to the hazardous effects of optical radiation on the retinal pigment epithelium and the photoreceptors. These data are further analyzed with regard to five potential long-term visual health problems; retinal degeneration, visual aging, disorder of visual development, ocular drug phototoxicity, and cataracts. Finally, epidemiologic principles for studying the relationships between optical radiation and long-term visual health problems are reviewed, concluding with the implications for future research and radiation protection. The contents include: historical perspectives; optical radiation and cataracts; the involvement of the retinal pigment epithelium (RPE); optical radiation damage to the ocular photoreceptors; possible role of optical radiation in retinal degenerations; optical radiation and the aged eye; optical radiation effects on aging and visual perception; optical radiation effects on visual development; and index

  18. Photodeposited diffractive optical elements of computer generated masks

    International Nuclear Information System (INIS)

    Mirchin, N.; Peled, A.; Baal-Zedaka, I.; Margolin, R.; Zagon, M.; Lapsker, I.; Verdyan, A.; Azoulay, J.

    2005-01-01

    Diffractive optical elements (DOE) were synthesized on plastic substrates using the photodeposition (PD) technique by depositing amorphous selenium (a-Se) films with argon lasers and UV spectra light. The thin films were deposited typically onto polymethylmethacrylate (PMMA) substrates at room temperature. Scanned beam and contact mask modes were employed using computer-designed DOE lenses. Optical and electron micrographs characterize the surface details. The films were typically 200 nm thick

  19. Teaching Diffraction with Hands-On Optical Spectrometry

    Science.gov (United States)

    Fischer, Robert

    2012-01-01

    Although the observation of optical spectra is common practice in physics classes, students are usually limited to a passive, qualitative observation of nice colours. This paper discusses a diffraction-based spectrometer that allows students to take quantitative measurements of spectral bands. Students can build it within minutes from generic…

  20. Ultrafast electron diffraction studies of optically excited thin bismuth films

    International Nuclear Information System (INIS)

    Rajkovic, Ivan

    2008-01-01

    This thesis contains work on the design and the realization of an experimental setup capable of providing sub-picosecond electron pulses for ultrafast electron diffraction experiments, and performing the study of ultrafast dynamics in bismuth after optical excitation using this setup. (orig.)

  1. Koch fractals in physical optics and their Fraunhofer diffraction patterns

    Czech Academy of Sciences Publication Activity Database

    Horváth, P.; Šmíd, Petr; Vašková, I.; Hrabovský, M.

    2010-01-01

    Roč. 121, č. 2 (2010), s. 206-2134 ISSN 0030-4026 R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : Koch fractal s * Fraunhofer diffraction patterns Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.454, year: 2010

  2. Ultrafast electron diffraction studies of optically excited thin bismuth films

    Energy Technology Data Exchange (ETDEWEB)

    Rajkovic, Ivan

    2008-10-21

    This thesis contains work on the design and the realization of an experimental setup capable of providing sub-picosecond electron pulses for ultrafast electron diffraction experiments, and performing the study of ultrafast dynamics in bismuth after optical excitation using this setup. (orig.)

  3. Optical diffraction by ordered 2D arrays of silica microspheres

    International Nuclear Information System (INIS)

    Shcherbakov, A.A.; Shavdina, O.; Tishchenko, A.V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.

    2017-01-01

    The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality. - Highlights: • High quality silica microsphere monolayer was fabricated. • Accurate measurements of diffraction efficiency angular dependencies. • Rigorous diffraction simulation of both ideal hexagonal and realistic microsphere arrangements. • Qualitative rationalization of the obtained results and the observed differences between the experiment and the theory.

  4. Theoretical and numerical investigations of sub-wavelength diffractive optical structures

    DEFF Research Database (Denmark)

    Dridi, Kim

    2000-01-01

    The work in this thesis concerns theoretical and numerical investigations of sub-wavelength diffractive optical structures, relying on advanced two-dimensional vectorial numerical models that have applications in Optics and Electromagnetics. Integrated Optics is predicted to play a major role......, such as in dielectric waveguides with gratings and periodic media or photonic crystal structures. The vectorial electromagnetic nature of light is therefore taken into account in the modeling of these diffractive structures. An electromagnetic vector-field model for optical components design based on the classical...... finite-difference time domain method and exact radiation integrals is implemented for the polarization where the electric field vector is perpendicular to the two dimentional plane of symmetry. The computational model solves the full vectorial time domain Maxwell equations with general sources...

  5. Phase-sensitive detection of optical resonances by using an acousto-optic modulator in the Raman - Nath diffraction mode

    International Nuclear Information System (INIS)

    Baryshev, V N; Domnin, Yu S; Kopylov, L N

    2007-01-01

    A new method for frequency control of an external cavity diode laser without direct modulation of the injection current is proposed. The Pound - Drever optical heterodyne technique or the method of frequency control by frequency-modulated sidebands, in which an acousto-optic modulator operating in the Raman - Nath diffraction mode is used as an external phase modulator, can be employed to obtain error signals upon automatic frequency locking of the diode laser to the saturated absorption resonances within the D 2 line of cesium atoms or to the optical cavity resonances. (control of laser radiation parameters)

  6. Optical diffraction by ordered 2D arrays of silica microspheres

    Science.gov (United States)

    Shcherbakov, A. A.; Shavdina, O.; Tishchenko, A. V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.

    2017-03-01

    The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality.

  7. Diffraction-enhanced imaging at the UK synchrotron radiation source

    International Nuclear Information System (INIS)

    Ibison, M.; Cheung, K.C.; Siu, K.; Hall, C.J.; Lewis, R.A.; Hufton, A.; Wilkinson, S.J.; Rogers, K.D.; Round, A.

    2005-01-01

    The Diffraction-Enhanced Imaging (DEI) system, which shares access to Beamline 7.6 on the Daresbury Synchrotron Radiation Source (SRS), is now in its third year of existence. The system was developed under a European Commission grant PHase Analyser SYstem (PHASY), won during the Fourth Framework. Typical applications continue to be the imaging of small biological specimens, using a beam of 12-17 keV after monochromation and up to 40 mm in width and 1-2 mm in height, although it is planned to investigate other materials as opportunity permits and time becomes available for more routine scientific use. Recent improvements have been made to the optical alignment procedure for setting up the station before imaging: a small laser device can now be set up to send a beam down the X-ray path through the four crystals, and a small photodiode, which has much better signal-to-noise characteristics than the ion chamber normally used for alignment, has been trailed successfully. A 3-D tomographic reconstruction capability has recently been developed and tested for DEI projection image sets, and will be applied to future imaging work on the SRS, in conjunction with volume visualization software. The next generation of DEI system, planned to operate at up to 60 keV on an SRS wiggler station, is in its design stage; it will feature much improved mechanics and mountings, especially for angular control, and a simplified alignment procedure to facilitate the necessary sharing of the SRS station

  8. Indoor optical wireless communication system using beam-steering by cascaded diffractive optical elements

    NARCIS (Netherlands)

    Oh, C.W.; Tangdiongga, E.; Koonen, A.M.J.; García-Blanco, S.M.; Boller, Kl.J.; Sefunc, M.A.; Geuzebroek, D.

    2014-01-01

    While the radio spectrum continues to struggle with a soaring bandwidth demand, the optical spectrum promises virtually unlimited license-free bandwidth. We report the feasibility of high-capacity point-to-point links for indoor optical wireless communication with cascaded diffractive optical

  9. The PIAA Coronagraph: Optical design and Diffraction Effects

    Science.gov (United States)

    Pluzhnik, E. A.; Guyon, O.; Ridgway, S.; Martinache, F.; Woodruff, R.; Blain, C.; Galicher, R.

    2005-12-01

    Properly apodized pupils are suitable for high dynamical range imaging of extrasolar terrestrial planets. Phase-induced amplitude apodization (PIAA) of the telescope pupil (Guyon 2003) combines the advantages of classical pupil apodization with full throughput, no loss of angular resolution and low chromaticity. Diffraction propagation effects can decrease both the achieved contrast and the spectral bandwidth of the coronagraph. We show here how the diffraction effects in the PIAA optics can be corrected by an appropriate optical design. The proposed hybrid coronagraph design preserves the 10-10 PSF contrast at ≈ 1.5 λ /d required for efficient exoplanet imaging over the whole visible spectrum. This work was carried out under JPL contract numbers 1254445 and 1257767 for Development of Technologies for the Terrestrial Planet Finder Mission, with the support and hospitality of the National Astronomical Observatory of Japan.

  10. X-ray diffraction microscopy based on refractive optics

    DEFF Research Database (Denmark)

    Poulsen, Henning Friis; Jakobsen, A. C.; Simons, Hugh

    2017-01-01

    A formalism is presented for dark‐field X‐ray microscopy using refractive optics. The new technique can produce three‐dimensional maps of lattice orientation and axial strain within millimetre‐sized sampling volumes and is particularly suited to in situ studies of materials at hard X‐ray energies....... An objective lens in the diffracted beam magnifies the image and acts as a very efficient filter in reciprocal space, enabling the imaging of individual domains of interest with a resolution of 100 nm. Analytical expressions for optical parameters such as numerical aperture, vignetting, and the resolution...

  11. Manipulating qudits spatial using programmable diffractive optical devices

    International Nuclear Information System (INIS)

    Lima, G.; Neves, L.; Saavedra, C.; Vargas, A.; Guzman, R.

    2009-01-01

    The generation of high-dimensional quantum states (qudits) is justified by the advantages that they can bring for the field of quantum information. These states for practical application in quantum communication must be of simple manipulation. Qudits can be generated by controlling the transverse momentum of the parametric down-converted photons. In this work, we show a simple technique for modifying these sates based on the use of programmable diffractive optical devices, which can act as spatial light modulators. (Author)

  12. Optical forces in a non-diffracting vortex beam

    Czech Academy of Sciences Publication Activity Database

    Šiler, Martin; Zemánek, Pavel

    2013-01-01

    Roč. 126, September (2013), s. 78-83 ISSN 0022-4073 R&D Projects: GA ČR GPP205/12/P868; GA MŠk LH12018; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : dielectric microparticle * non-diffracting vortex beam Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.288, year: 2013

  13. X-ray diffraction microtomography using synchrotron radiation

    CERN Document Server

    Barroso, R C; Jesus, E F O; Oliveira, L F

    2001-01-01

    The X-ray diffraction computed tomography technique is based on the interference phenomena of the coherent scatter. For low-momentum transfer, it is most probable that the scattering interaction will be coherent. A selective discrimination of a given element in a scanned specimen can be realized by fixing the Bragg angle which produces an interference peak and then, to carry out the computed tomography in the standard mode. The image reconstructed exalts the presence of this element with respect to other ones in a sample. This work reports the feasibility of a non-destructive synchrotron radiation X-ray diffraction imaging technique. This research was performed at the X-ray Diffraction beam line of the National Synchrotron Light Laboratory (LNLS) in Brazil. The coherent scattering properties of different tissue and bone substitute materials were evaluated. Furthermore, diffraction patterns of some polycrystalline solids were studied due to industrial and environmental human exposure to these metals. The obtai...

  14. Radiation damage in optical fibers

    International Nuclear Information System (INIS)

    Lyons, P.B.; Looney, L.D.; Ogle, J.W.

    1983-01-01

    Optical fibers provide important advantages over coaxial cables for many data transmission applications. Some of these applications require that the fibers transmit data during a radiation pulse. Other applications utilize the fiber as a radiation-to-light transducer. In either case, radiation-induced luminescence and absorption must be understood. Most studies of radiation effects in fibers have emphasized time scales of interest in telecommunication systems, from the msec to hour range. Few studies have concentrated on response at times below 1 + s. At Los Alamos, both laboratory electron accelerators and nuclear tests have been used as radiation sources to probe this early time region. The use of a fiber (or any optical medium) as a Cerenkov radiation-to-light transducer is discussed. Since the radiation induces attenuation in the medium, the light output is not proportional to the radiation input. The nonlinearity introduced by this attenuation is calculated

  15. Takagi-Taupin description of x-ray dynamical diffraction from diffractive optics with large numerical aperture

    International Nuclear Information System (INIS)

    Yan Hanfei; Maser, Joerg; Macrander, Albert; Shen Qun; Vogt, Stefan; Stephenson, G. Brian; Kang, Hyon Chol

    2007-01-01

    We present a formalism of x-ray dynamical diffraction from volume diffractive optics with large numerical aperture and high aspect ratio, in an analogy to the Takagi-Taupin equations [Acta Crystallogr. 15, 1311 (1962); Bull. Soc. Fr. Mineral. Crystallogr. 87, 469 (1964)] for strained single crystals. We derive a set of basic equations for dynamical diffraction from volume diffractive optics, which enable us to study the focusing property of these optics with various grating profiles. We study volume diffractive optics that satisfy the Bragg condition to various degrees, namely, flat, tilted, and wedged geometries, and derive the curved geometries required for ultimate focusing. We show that the curved geometries satisfy both the Bragg condition everywhere and phase requirement for point focusing and effectively focus hard x rays to a scale close to the wavelength. Our calculations were made for an x-ray wavelength of 0.064 nm (19.5 keV)

  16. Focusing Optics for High-Energy X-ray Diffraction

    DEFF Research Database (Denmark)

    Leinert, U.; Schulze, C.; Honkimäki, V.

    1998-01-01

    Novel focusing optical devices have been developed for synchrotron radiation in the energy range 40-100 keV. Firstly, a narrow-band-pass focusing energy-tuneable fixed-exit monochromator was constructed by combining meridionally bent Laue and Bragg crystals. Dispersion compensation was applied...

  17. Single-pulse x-ray diffraction using polycapillary optics for in situ dynamic diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Maddox, B. R., E-mail: maddox3@llnl.gov; Akin, M. C., E-mail: akin1@llnl.gov; Teruya, A.; Hunt, D.; Hahn, D.; Cradick, J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Morgan, D. V. [National Security Technologies LLC, Los Alamos, New Mexico 87544 (United States)

    2016-08-15

    Diagnostic use of single-pulse x-ray diffraction (XRD) at pulsed power facilities can be challenging due to factors such as the high flux and brightness requirements for diffraction and the geometric constraints of experimental platforms. By necessity, the x-ray source is usually positioned very close, within a few inches of the sample. On dynamic compression platforms, this puts the x-ray source in the debris field. We coupled x-ray polycapillary optics to a single-shot needle-and-washer x-ray diode source using a laser-based alignment scheme to obtain high-quality x-ray diffraction using a single 16 ns x-ray pulse with the source >1 m from the sample. The system was tested on a Mo sample in reflection geometry using 17 keV x-rays from a Mo anode. We also identified an anode conditioning effect that increased the x-ray intensity by 180%. Quantitative measurements of the x-ray focal spot produced by the polycapillary yielded a total x-ray flux on the sample of 3.3 ± 0.5 × 10{sup 7} molybdenum Kα photons.

  18. Optical diffraction tomography: accuracy of an off-axis reconstruction

    Science.gov (United States)

    Kostencka, Julianna; Kozacki, Tomasz

    2014-05-01

    Optical diffraction tomography is an increasingly popular method that allows for reconstruction of three-dimensional refractive index distribution of semi-transparent samples using multiple measurements of an optical field transmitted through the sample for various illumination directions. The process of assembly of the angular measurements is usually performed with one of two methods: filtered backprojection (FBPJ) or filtered backpropagation (FBPP) tomographic reconstruction algorithm. The former approach, although conceptually very simple, provides an accurate reconstruction for the object regions located close to the plane of focus. However, since FBPJ ignores diffraction, its use for spatially extended structures is arguable. According to the theory of scattering, more precise restoration of a 3D structure shall be achieved with the FBPP algorithm, which unlike the former approach incorporates diffraction. It is believed that with this method one is allowed to obtain a high accuracy reconstruction in a large measurement volume exceeding depth of focus of an imaging system. However, some studies have suggested that a considerable improvement of the FBPP results can be achieved with prior propagation of the transmitted fields back to the centre of the object. This, supposedly, enables reduction of errors due to approximated diffraction formulas used in FBPP. In our view this finding casts doubt on quality of the FBPP reconstruction in the regions far from the rotation axis. The objective of this paper is to investigate limitation of the FBPP algorithm in terms of an off-axis reconstruction and compare its performance with the FBPJ approach. Moreover, in this work we propose some modifications to the FBPP algorithm that allow for more precise restoration of a sample structure in off-axis locations. The research is based on extensive numerical simulations supported with wave-propagation method.

  19. 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.

  20. Effect of environmental temperature on diffraction efficiency for multilayer diffractive optical elements in Mid-wave infrared

    Science.gov (United States)

    Piao, Mingxu; Cui, Qingfeng; Zhu, Hao; Zhang, Bo

    2014-11-01

    In this paper, the effect of environmental temperature change on multilayer diffractive optical elements (MLDOEs) is evaluated from the viewpoint of the diffraction efficiency and the polychromatic integral diffraction efficiency (PIDE). As environmental temperature changes, the microstructure heights of MLDOEs expand or contract, and refractive indices of substrate materials also change. Based on the changes in microstructure height and substrate material index with environmental temperature, the theoretical relation between diffraction efficiency of MLDOEs and environmental temperature is deduced. A practical 3-5μm Mid-wave infrared (MWIR) optical system designed with a MLDOE, which made of ZNSE and GE, is discussed to illustrate the influence of environmental temperature change. The result shows that diffraction efficiency reduction is no more than 85% and PIDE reduction is less than 50% when environmental temperature ranges from -20°C to 60°C. According to the calculated diffraction efficiency in different environmental temperatures, the MTF of hybrid optical system is modified and the modified MTF curve is compared with the original MTF curve. Although the hybrid optical system achieved passive athermalization in above environmental temperature range, the modified MTF curve also remarkably decline in environmental temperature extremes after the consideration of diffraction efficiency change of MLDOE. It is indicated that the image quality of hybrid optical system with ZNSE-GE MLDOE is significantly sensitive to environmental temperature change. The analysis result can be used for optical engineering design with MLDOEs in MWIR.

  1. Refractive and diffractive neutron optics with reduced chromatic aberration

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, S.O., E-mail: stefan.poulsen@northwestern.edu [NEXMAP, Department of Physics, Technical University of Denmark, Anker Engelunds Vej 1, 2800 Kgs. Lyngby (Denmark); Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208 (United States); Poulsen, H.F. [NEXMAP, Department of Physics, Technical University of Denmark, Anker Engelunds Vej 1, 2800 Kgs. Lyngby (Denmark); Bentley, P.M. [European Spallation Source ESS AB, Box 176, 221 00 Lund (Sweden)

    2014-12-11

    Thermal neutron beams are an indispensable tool in physics research. The spatial and the temporal resolution attainable in experiments are dependent on the flux and collimation of the neutron beam which remain relatively poor, even for modern neutron sources. These difficulties may be mitigated by the use of optics for focusing and imaging. Refractive and diffractive optical elements, e.g. compound refractive lenses and Fresnel zone plates, are attractive due to their low cost, and simple alignment. These optical elements, however, suffer from chromatic aberration, which limit their effectiveness to highly monochromatic beams. This paper presents two novel concepts for focusing and imaging non-monochromatic thermal neutron beams with well-known optical elements: (1) a fast mechanical transfocator based on a compound refractive lens, which actively varies the number of individual lenses in the beam path to focus and image a time-of-flight beam, and (2) a passive optical element consisting of a compound refractive lens, and a Fresnel zone plate, which may focus and image both continuous and pulsed neutron beams.

  2. Aplanatic grazing incidence diffraction grating: a new optical element

    International Nuclear Information System (INIS)

    Hettrick, M.C.

    1986-01-01

    We present the theory of a grazing incidence reflection grating capable of imaging at submicron resolution. The optic is mechanically ruled on a spherical or cylindrical surface with varied groove spacings, delivering diffraction-limited response and a wide field of view at a selected wavelength. Geometrical aberrations are calculated on the basis of Fermat's principle, revealing significant improvements over a grazing incidence mirror. Aplanatic and quasi-aplanatic versions of the grating have applications in both imaging and scanning microscopes, microprobes, collimators, and telescopes. A 2-D crossed system of such gratings, similar to the grazing incidence mirror geometry of Kirkpatrick and Baez, could potentially provide spatial resolutions of --200 A

  3. Method for the diffraction of terrestrial radiation, GAMMA radiation, etc

    International Nuclear Information System (INIS)

    Busenbach, P.

    1975-01-01

    The patent claim concerns shielding against so-called earth radiation. These rays originate from water veins etc., cannot be defined any closer, and are supposed to cause injury to health. The author claims that shielding is possible with the aid of welding electrodes which have cores of nickel. (ORU/LN) [de

  4. Time-resolved diffraction studies of muscle using synchrotron radiation

    International Nuclear Information System (INIS)

    Harford, Jeffrey; Squire, John

    1997-01-01

    Muscle contraction is one of those biological phenomena that we can all appreciate in our everyday lives. Sometimes it is when we are resting quietly and are aware of our heartbeat. At other times it may be when we are exerting ourselves and become short of breath, or when we exercise for a long period and our muscles start to ache. The way in which muscles produce force has exercised the minds of philosophers and scientists at least since the days of Erasistratus in the third century BC. Nowadays, of course, we know a very great deal about muscle structure, physiology and biochemistry, but we still do not know exactly what the molecular process is that produces movement. An ideal way of probing this process would be to be able to obtain signals from the relevant molecules as they actually go through their normal force-generating routine in an active muscle. The spatial dimensions involved are in the region of 1-50 nm, thus precluding the use of light microscopy, and the time regime is microseconds to milliseconds. Techniques with the appropriate spatial resolution might be electron microscopy and x-ray diffraction, but electron microscopy cannot yet be carried out on living tissue. X-ray diffraction methods can clearly have the right sort of spatial resolution, but what about recording diffraction patterns in the very short times involved (say 1 ms)? It is here that the high flux from synchrotron storage rings comes into its own. Using synchrotron radiation from, say, the SRS at the CCLRC Daresbury Laboratory it is possible to record x-ray diffraction patterns from living muscles in the millisecond time regime and to follow how these diffraction patterns change as the muscles go through typical contraction cycles. Unfortunately, x-ray diffraction is not a direct imaging method; the observed distribution of diffracted intensity needs to be interpreted in some way to give useful information on the spatial relationships of the force-generating molecules. This review

  5. Transition operators in electromagnetic-wave diffraction theory. II - Applications to optics

    Science.gov (United States)

    Hahne, G. E.

    1993-01-01

    The theory developed by Hahne (1992) for the diffraction of time-harmonic electromagnetic waves from fixed obstacles is briefly summarized and extended. Applications of the theory are considered which comprise, first, a spherical harmonic expansion of the so-called radiation impedance operator in the theory, for a spherical surface, and second, a reconsideration of familiar short-wavelength approximation from the new standpoint, including a derivation of the so-called physical optics method on the basis of quasi-planar approximation to the radiation impedance operator, augmented by the method of stationary phase. The latter includes a rederivation of the geometrical optics approximation for the complete Green's function for the electromagnetic field in the presence of a smooth- and a convex-surfaced perfectly electrically conductive obstacle.

  6. Optical diffraction tomography in an inhomogeneous background medium

    International Nuclear Information System (INIS)

    Devaney, A; Cheng, J

    2008-01-01

    The filtered back-propagation algorithm (FBP algorithm) is a computationally fast and efficient inversion algorithm for reconstructing the 3D index of refraction distribution of weak scattering samples in free space from scattered field data collected in a set of coherent optical scattering experiments. This algorithm is readily derived using classical Fourier analysis applied to the Born or Rytov weak scattering models appropriate to scatterers embedded in a non-attenuating uniform background. In this paper, the inverse scattering problem for optical diffraction tomography (ODT) is formulated using the so-called distorted wave Born and Rytov approximations and a generalized version of the FBP algorithm is derived that applies to weakly scattering samples that are embedded in realistic, multiple scattering ODT experimental configurations. The new algorithms are based on the generalized linear inverse of the linear transformation relating the scattered field data to the complex index of refraction distribution of the scattering samples and are in the form of a superposition of filtered data, computationally back propagated into the ODT experimental configuration. The paper includes a computer simulation comparing the generalized Born and Rytov based FBP inversion algorithms as well as reconstructions generated using the generalized Born based FBP algorithm of a step index optical fiber from experimental ODT data

  7. 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.

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

    KAUST Repository

    Stegenburgs, Edgars; Alias, Mohd Sharizal B.; Ng, Tien Khee; Ooi, Boon S.

    2017-01-01

    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.

  9. Method of lightening radiation darkened optical elements

    International Nuclear Information System (INIS)

    Reich, F.R.; Schwankoff, A.R.

    1980-01-01

    A method of lightening a radiation-darkened optical element in which visible optical energy or electromagnetic radiation having a wavelength in the range of from about 2000 to about 20,000 angstroms is directed into the radiation-darkened optical element; the method may be used to lighten radiation-darkened optical element in-situ during the use of the optical element to transmit data by electronically separating the optical energy from the optical output by frequency filtering, data cooling, or interlacing the optic energy between data intervals

  10. Variable-metric diffraction crystals for x-ray optics

    International Nuclear Information System (INIS)

    Smither, R.K.; Fernandez, P.B.

    1992-01-01

    A variable-metric (VM) crystal is one in which the spacing between the crystalline planes changes with position in the crystal. This variation can be either parallel to the crystalline planes or perpendicular to the crystalline planes of interest and can be produced by either introducing a thermal gradient in the crystal or by growing a crystal made of two or more elements and changing the relative percentages of the two elements as the crystal is grown. A series of experiments were performed in the laboratory to demonstrate the principle of the variable-metric crystal and its potential use in synchrotron beam lines. One of the most useful applications of the VM crystal is to increase the number of photons per unit bandwidth in a diffracted beam without losing any of the overall intensity. In a normal synchrotron beam line that uses a two-crystal monochromator, the bandwidth of the diffracted photon beam is determined by the vertical opening angle of the beam which is typically 0.10--0.30 mrad or 20--60 arcsec. When the VM crystal approach is applied, the bandwidth of the beam can be made as narrow as the rocking curve of the diffracting crystal, which is typically 0.005--0.050 mrad or 1--10 arcsec. Thus a very large increase of photons per unit bandwidth (or per unit energy) can be achieved through the use of VM crystals. When the VM principle is used with bent crystals, new kinds of x-ray optical elements can be generated that can focus and defocus x-ray beams much like simple lenses where the focal length of the lens can be changed to match its application. Thus both large magnifications and large demagnifications can be achieved as well as parallel beams with narrow bandwidths

  11. Advances in thin film diffraction instrumentation by X-ray optics

    International Nuclear Information System (INIS)

    Haase, A.

    1996-01-01

    The structural characterisation of thin films requires a parallel X-ray beam of high intensity. Parallel beam geometry is commonly used in high resolution and single crystal experiments, but also in the field of X-ray diffraction for polycrystalline material (e.g. in phase, texture and stress analysis). For grazing incidence diffraction (GID), the use of small slits on the primary side and of long soller slits with a flat monochromator on the secondary side is standard. New optical elements have been introduced with polychromatic or monochromatic radiation. By means of different applications the results are compared with those of classical beam optics. X-ray fiber optics utilize total external reflection of X-rays on smooth surfaces. Effects of monochromatization are presented. In many fields of application, fiber optics may replace conventional collimators. The use of primary and secondary channel cut crystals can also produce a high parallel monochromatic X-ray beam. A parabolically bent graded multilayer produces a monochromatic parallel beam of high intensity. Compared with classical Bragg-Brentano (focussing) geometry, excellent results have been obtained, especially for samples with an irregular shape. In combination with a channel cut monochromator there is a substantial gain in intensity leading to an increase of the dynamic intensity range of rocking curves

  12. Advances in thin film diffraction instrumentation by X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Haase, A [Rich. Seifert and Co., Analytical X-ray Systems, Ahrensburg (Germany)

    1996-09-01

    The structural characterisation of thin films requires a parallel X-ray beam of high intensity. Parallel beam geometry is commonly used in high resolution and single crystal experiments, but also in the field of X-ray diffraction for polycrystalline material (e.g. in phase, texture and stress analysis). For grazing incidence diffraction (GID), the use of small slits on the primary side and of long soller slits with a flat monochromator on the secondary side is standard. New optical elements have been introduced with polychromatic or monochromatic radiation. By means of different applications the results are compared with those of classical beam optics. X-ray fiber optics utilize total external reflection of X-rays on smooth surfaces. Effects of monochromatization are presented. In many fields of application, fiber optics may replace conventional collimators. The use of primary and secondary channel cut crystals can also produce a high parallel monochromatic X-ray beam. A parabolically bent graded multilayer produces a monochromatic parallel beam of high intensity. Compared with classical Bragg-Brentano (focussing) geometry, excellent results have been obtained, especially for samples with an irregular shape. In combination with a channel cut monochromator there is a substantial gain in intensity leading to an increase of the dynamic intensity range of rocking curves.

  13. STUDY ON HIGH RESOLUTION MEMBRANE-BASED DIFFRACTIVE OPTICAL IMAGING ON GEOSTATIONARY ORBIT

    Directory of Open Access Journals (Sweden)

    J. Jiao

    2017-05-01

    Full Text Available Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the “6+1” petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

  14. Study on High Resolution Membrane-Based Diffractive Optical Imaging on Geostationary Orbit

    Science.gov (United States)

    Jiao, J.; Wang, B.; Wang, C.; Zhang, Y.; Jin, J.; Liu, Z.; Su, Y.; Ruan, N.

    2017-05-01

    Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the "6+1" petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

  15. Ultrashort electron bunch length measurement with diffraction radiation deflector

    Science.gov (United States)

    Xiang, Dao; Huang, Wen-Hui

    2007-01-01

    In this paper, we propose a novel method to measure electron bunch length with a diffraction radiation (DR) deflector which is composed of a DR radiator and three beam position monitors (BPMs). When an electron beam passes through a metallic aperture which is tilted by 45 degrees with respect to its trajectory, backward DR that propagates perpendicular to the beam’s trajectory is generated which adds a transverse deflection to the beam as a result of momentum conservation. The deflection is found to be largely dependent on the bunch length and could be easily observed with a downstream BPM. Detailed investigations show that this method has wide applicability, high temporal resolution, and great simplicity.

  16. Ultrashort electron bunch length measurement with diffraction radiation deflector

    Directory of Open Access Journals (Sweden)

    Dao Xiang

    2007-01-01

    Full Text Available In this paper, we propose a novel method to measure electron bunch length with a diffraction radiation (DR deflector which is composed of a DR radiator and three beam position monitors (BPMs. When an electron beam passes through a metallic aperture which is tilted by 45 degrees with respect to its trajectory, backward DR that propagates perpendicular to the beam’s trajectory is generated which adds a transverse deflection to the beam as a result of momentum conservation. The deflection is found to be largely dependent on the bunch length and could be easily observed with a downstream BPM. Detailed investigations show that this method has wide applicability, high temporal resolution, and great simplicity.

  17. Diffractive optical variable image devices generated by maskless interferometric lithography for optical security

    Science.gov (United States)

    Cabral, Alexandre; Rebordão, José M.

    2011-05-01

    In optical security (protection against forgery and counterfeit of products and documents) the problem is not exact reproduction but the production of something sufficiently similar to the original. Currently, Diffractive Optically Variable Image Devices (DOVID), that create dynamic chromatic effects which may be easily recognized but are difficult to reproduce, are often used to protect important products and documents. Well known examples of DOVID for security are 3D or 2D/3D holograms in identity documents and credit cards. Others are composed of shapes with different types of microstructures yielding by diffraction to chromatic dynamic effects. A maskless interferometric lithography technique to generate DOVIDs for optical security is presented and compared to traditional techniques. The approach can be considered as a self-masking focused holography on planes tilted with respect to the reference optical axes of the system, and is based on the Scheimpflug and Hinge rules. No physical masks are needed to ensure optimum exposure of the photosensitive film. The system built to demonstrate the technique relies on the digital mirrors device MOEMS technology from Texas Instruments' Digital Light Processing. The technique is linear on the number of specified colors and does not depend either on the area of the device or the number of pixels, factors that drive the complexity of dot-matrix based systems. The results confirmed the technique innovation and capabilities in the creation of diffractive optical elements for security against counterfeiting and forgery.

  18. Ultra-high accuracy optical testing: creating diffraction-limitedshort-wavelength optical systems

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Rekawa, Senajith B.; Denham, Paul E.; Liddle, J. Alexander; Gullikson, Eric M.; Jackson, KeithH.; Anderson, Erik H.; Taylor, John S.; Sommargren, Gary E.; Chapman,Henry N.; Phillion, Donald W.; Johnson, Michael; Barty, Anton; Soufli,Regina; Spiller, Eberhard A.; Walton, Christopher C.; Bajt, Sasa

    2005-08-03

    Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2-20-nm wavelength range (60-600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5-1-{angstrom} and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL's Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (f/6.25 to f/1.67). These projection-imaging lenses were created for the semiconductor industry's advanced research in EUV photolithography, a technology slated for introduction in 2009-13. This paper reviews the methods used and our program's accomplishments to date.

  19. Ultra-high accuracy optical testing: creating diffraction-limited short-wavelength optical systems

    International Nuclear Information System (INIS)

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Rekawa, Senajith B.; Denham, Paul E.; Liddle, J. Alexander; Gullikson, Eric M.; Jackson, KeithH.; Anderson, Erik H.; Taylor, John S.; Sommargren, Gary E.; Chapman, Henry N.; Phillion, Donald W.; Johnson, Michael; Barty, Anton; Soufli, Regina; Spiller, Eberhard A.; Walton, Christopher C.; Bajt, Sasa

    2005-01-01

    Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2-20-nm wavelength range (60-600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5-1-(angstrom) and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL's Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (f/6.25 to f/1.67). These projection-imaging lenses were created for the semiconductor industry's advanced research in EUV photolithography, a technology slated for introduction in 2009-13. This paper reviews the methods used and our program's accomplishments to date

  20. Optical microparticle manipulation advances and new capabilities offered by diffractive optics

    International Nuclear Information System (INIS)

    Sojfer, V.A.; Kotlyar, V.V.; Khonina, S.N.

    2004-01-01

    The review deals with a promising area in laser optics - optical manipulation. The object under manipulation can be of various nature: from a colloid particle to a molecule, from cell, virus, to a micromechanism part, etc. In the first part of this work a concise review of the articles on optical manipulation of microparticles and atoms published in the last two decades is presented. The second part is devoted t the production of laser beams with self-reproduction properties. Such beams can be most effectively produced using diffractive optical elements (DOEs). The DOE-generated self-reproducing laser beams (stable, axially periodic, rotating, and multiorder) offer new opportunities in optical manipulation of micro- and nano-objects [ru

  1. Effect of multiple circular holes Fraunhofer diffraction for the infrared optical imaging

    Science.gov (United States)

    Lu, Chunlian; Lv, He; Cao, Yang; Cai, Zhisong; Tan, Xiaojun

    2014-11-01

    With the development of infrared optics, infrared optical imaging systems play an increasingly important role in modern optical imaging systems. Infrared optical imaging is used in industry, agriculture, medical, military and transportation. But in terms of infrared optical imaging systems which are exposed for a long time, some contaminations will affect the infrared optical imaging. When the contamination contaminate on the lens surface of the optical system, it would affect diffraction. The lens can be seen as complementary multiple circular holes screen happen Fraunhofer diffraction. According to Babinet principle, you can get the diffraction of the imaging system. Therefore, by studying the multiple circular holes Fraunhofer diffraction, conclusions can be drawn about the effect of infrared imaging. This paper mainly studies the effect of multiple circular holes Fraunhofer diffraction for the optical imaging. Firstly, we introduce the theory of Fraunhofer diffraction and Point Spread Function. Point Spread Function is a basic tool to evaluate the image quality of the optical system. Fraunhofer diffraction will affect Point Spread Function. Then, the results of multiple circular holes Fraunhofer diffraction are given for different hole size and hole spacing. We choose the hole size from 0.1mm to 1mm and hole spacing from 0.3mm to 0.8mm. The infrared wavebands of optical imaging are chosen from 1μm to 5μm. We use the MATLAB to simulate light intensity distribution of multiple circular holes Fraunhofer diffraction. Finally, three-dimensional diffraction maps of light intensity are given to contrast.

  2. Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

    Science.gov (United States)

    Ramos-Izquierdo, Luis A.

    2011-01-01

    A diffractive optic element (DOE) can be used as a beam splitter to generate multiple laser beams from a single input laser beam. This technology has been recently used in LRO s Lunar Orbiter Laser Altimeter (LOLA) instrument to generate five laser beams that measure the lunar topography from a 50-km nominal mapping orbit (see figure). An extension of this approach is to use a multiple-zone DOE to allow a laser altimeter instrument to operate over a wider range of distances. In particular, a multiple-zone DOE could be used for applications that require both mapping and landing on a planetary body. In this case, the laser altimeter operating range would need to extend from several hundred kilometers down to a few meters. The innovator was recently involved in an investigation how to modify the LOLA instrument for the OSIRIS asteroid mapping and sample return mission. One approach is to replace the DOE in the LOLA laser beam expander assembly with a multiple-zone DOE that would allow for the simultaneous illumination of the asteroid with mapping and landing laser beams. The proposed OSIRIS multiple-zone DOE would generate the same LOLA five-beam output pattern for high-altitude topographic mapping, but would simultaneously generate a wide divergence angle beam using a small portion of the total laser energy for the approach and landing portion of the mission. Only a few percent of the total laser energy is required for approach and landing operations as the return signal increases as the inverse square of the ranging height. A wide divergence beam could be implemented by making the center of the DOE a diffractive or refractive negative lens. The beam energy and beam divergence characteristics of a multiple-zone DOE could be easily tailored to meet the requirements of other missions that require laser ranging data. Current single-zone DOE lithographic manufacturing techniques could also be used to fabricate a multiple-zone DOE by masking the different DOE zones during

  3. Capillary optics for radiation focusing

    International Nuclear Information System (INIS)

    Peurrung, A.J.; Reeder, P.L.; Bliss, M.; Craig, R.A.; Lepel, E.A.; Stromswold, D.C.; Stoffels, J.; Sunberg, D.S.; Tenny, H.

    1996-11-01

    Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lenses using 58 Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics

  4. Improved Resolution Optical Time Stretch Imaging Based on High Efficiency In-Fiber Diffraction.

    Science.gov (United States)

    Wang, Guoqing; Yan, Zhijun; Yang, Lei; Zhang, Lin; Wang, Chao

    2018-01-12

    Most overlooked challenges in ultrafast optical time stretch imaging (OTSI) are sacrificed spatial resolution and higher optical loss. These challenges are originated from optical diffraction devices used in OTSI, which encode image into spectra of ultrashort optical pulses. Conventional free-space diffraction gratings, as widely used in existing OTSI systems, suffer from several inherent drawbacks: limited diffraction efficiency in a non-Littrow configuration due to inherent zeroth-order reflection, high coupling loss between free-space gratings and optical fibers, bulky footprint, and more importantly, sacrificed imaging resolution due to non-full-aperture illumination for individual wavelengths. Here we report resolution-improved and diffraction-efficient OTSI using in-fiber diffraction for the first time to our knowledge. The key to overcome the existing challenges is a 45° tilted fiber grating (TFG), which serves as a compact in-fiber diffraction device offering improved diffraction efficiency (up to 97%), inherent compatibility with optical fibers, and improved imaging resolution owning to almost full-aperture illumination for all illumination wavelengths. 50 million frames per second imaging of fast moving object at 46 m/s with improved imaging resolution has been demonstrated. This conceptually new in-fiber diffraction design opens the way towards cost-effective, compact and high-resolution OTSI systems for image-based high-throughput detection and measurement.

  5. Wave-guided Optical Waveguides tracked and coupled using dynamic diffractive optics

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Villangca, Mark Jayson; Bañas, Andrew Rafael

    With light’s miniscule momentum, shrinking robotics down to the micro- and nano-scale regime creates opportunities for exploiting optical forces and near-field light delivery in advanced actuation and control atthe smallest physical dimensions. Advancing light-driven nano- or micro-actuation requ......With light’s miniscule momentum, shrinking robotics down to the micro- and nano-scale regime creates opportunities for exploiting optical forces and near-field light delivery in advanced actuation and control atthe smallest physical dimensions. Advancing light-driven nano- or micro...... waveguides (WOWs) [2]. As the WOWs are optically trapped and maneuvered in 3D-space, it is important to maintain efficient light-coupling through these free-standing waveguides within their operating volume [3]. We propose the use ofdynamic diffractive techniques to create focal spots that will track...... and couple to the WOWs during full volume operation. This is done by using a spatial light modulator to encode the necessary diffractive phase patterns to generate the multiple and dynamic coupling spots. The method is initially tested for a single WOW and we have experimentally demonstrated dynamic tracking...

  6. Physical optics-based diffraction coefficient for a wedge with different face impedances.

    Science.gov (United States)

    Umul, Yusuf Ziya

    2018-03-20

    A new diffraction field expression is introduced with the aid of the modified theory of physical optics for a wedge with different face impedances. First, the scattered geometrical optics fields are determined when both faces of the wedge are illuminated by the incident wave. The geometrical optics waves are then expressed in terms of the sum of two different fields that occur for different impedance wedges. The diffracted fields are determined for the two cases separately, and the total diffracted field is obtained as a sum of these waves. Lastly, the uniform field expressions are obtained, and the resultant fields are numerically compared with the solution of Maliuzhinets.

  7. Optimizing Monocapillary Optics for Synchrotron X-ray Diffraction, Fluorescence Imaging, and Spectroscopy Applications

    International Nuclear Information System (INIS)

    Bilderback, Donald H.; Kazimirov, Alexander; Gillilan, Richard; Cornaby, Sterling; Woll, Arthur; Zha, Chang-Sheng; Huang Rong

    2007-01-01

    A number of synchrotron x-ray applications such as powder diffraction in diamond anvil cells, microbeam protein crystallography, x-ray fluorescence imaging, etc. can benefit from using hollow glass monocapillary optics to improve the flux per square micron on a sample. We currently draw glass tubing into the desired elliptical shape so that only one-bounce under total reflection conditions is needed to bring the x-ray beam to a focus at a 25 to 50 mm distance beyond the capillary tip. For modest focal spot sizes of 10 to 20 microns, we can increase the intensity per square micron by factors of 10 to 1000. We show some of the results obtained at CHESS and Hasylab with capillaries focusing 5 to 40 keV radiation, their properties, and how even better the experimental results could be if more ideal capillaries were fabricated in the future

  8. Design and fabrication of diffractive optical elements with MATLAB

    National Research Council Canada - National Science Library

    Bhattacharya, Shanti (Professor in Optics); Vijayakumar, Anand

    2017-01-01

    ... their diffraction patterns using MATLAB. The fundamentals of fabrication techniques such as photolithography, electron beam lithography, and focused ion beam lithography with basic instructions for the beginner are presented...

  9. Influence of beam divergence on form-factor in X-ray diffraction radiation

    International Nuclear Information System (INIS)

    Sergeeva, D.Yu.; Tishchenko, A.A.; Strikhanov, M.N.

    2015-01-01

    Diffraction radiation from divergent beam is considered in terms of radiation in UV and X-ray range. Scedastic form of Gaussian distribution of the particle in the bunch, i.e. Gaussian distribution with changing dispersion has been used, which is more adequate for description of divergent beams than often used Gaussian distribution with constant dispersion. Both coherent and incoherent form-factors are taken into account. The conical diffraction effect in diffraction radiation is proved to make essential contribution in spectral-angular characteristics of radiation from a divergent beam

  10. Diffractive generalized phase contrast for adaptive phase imaging and optical security

    DEFF Research Database (Denmark)

    Palima, Darwin; Glückstad, Jesper

    2012-01-01

    We analyze the properties of Generalized Phase Contrast (GPC) when the input phase modulation is implemented using diffractive gratings. In GPC applications for patterned illumination, the use of a dynamic diffractive optical element for encoding the GPC input phase allows for onthe- fly optimiza...... security applications and can be used to create phasebased information channels for enhanced information security....

  11. Optical double-image cryptography based on diffractive imaging with a laterally-translated phase grating.

    Science.gov (United States)

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

    2011-10-10

    In this paper, we propose a method using structured-illumination-based diffractive imaging with a laterally-translated phase grating for optical double-image cryptography. An optical cryptosystem is designed, and multiple random phase-only masks are placed in the optical path. When a phase grating is laterally translated just before the plaintexts, several diffraction intensity patterns (i.e., ciphertexts) can be correspondingly obtained. During image decryption, an iterative retrieval algorithm is developed to extract plaintexts from the ciphertexts. In addition, security and advantages of the proposed method are analyzed. Feasibility and effectiveness of the proposed method are demonstrated by numerical simulation results. © 2011 Optical Society of America

  12. Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

    Directory of Open Access Journals (Sweden)

    Wyatt Adams

    2016-10-01

    Full Text Available Near-field optics and superlenses for imaging beyond Abbe’s diffraction limit are reviewed. A comprehensive and contemporary background is given on scanning near-field microscopy and superlensing. Attention is brought to recent research leveraging scanning near-field optical microscopy with superlenses for new nano-imaging capabilities. Future research directions are explored for realizing the goal of low-cost and high-performance sub-diffraction-limited imaging systems.

  13. Fabrication of amplitude-phase type diffractive optical elements in aluminium films

    Science.gov (United States)

    Fomchenkov, S. A.; Butt, M. A.

    2017-11-01

    In the course of studies have been conducted a method of forming the phase diffractive optical elements (DOEs) by direct laser writing in thin films of aluminum. The quality of the aluminum films were investigated depending on the parameters of magnetron sputtering process. Moreover, the parameters of the laser writing process in thin films of aluminum were optimized. The structure of phase diffractive optical elements was obtained by the proposed method.

  14. Radiation cured coatings for fiber optics

    International Nuclear Information System (INIS)

    Ketley, A.D.; Morgan, C.R.

    1978-01-01

    A continuous protective coating is formed on a fiber optic by coating the fiber optic in a bath of a liquid radiation curable composition at a temperature up to 90 0 C and exposing the coated conductor to ultraviolet or high energy ionizing radiation to cure the coating

  15. Magnetic resonance imaging of radiation optic neuropathy

    International Nuclear Information System (INIS)

    Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S.

    1990-01-01

    Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence

  16. Theoretical description and design of nanomaterial slab waveguides: application to compensation of optical diffraction.

    Science.gov (United States)

    Kivijärvi, Ville; Nyman, Markus; Shevchenko, Andriy; Kaivola, Matti

    2018-04-02

    Planar optical waveguides made of designable spatially dispersive nanomaterials can offer new capabilities for nanophotonic components. As an example, a thin slab waveguide can be designed to compensate for optical diffraction and provide divergence-free propagation for strongly focused optical beams. Optical signals in such waveguides can be transferred in narrow channels formed by the light itself. We introduce here a theoretical method for characterization and design of nanostructured waveguides taking into account their inherent spatial dispersion and anisotropy. Using the method, we design a diffraction-compensating slab waveguide that contains only a single layer of silver nanorods. The waveguide shows low propagation loss and broadband diffraction compensation, potentially allowing transfer of optical information at a THz rate.

  17. Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

    Science.gov (United States)

    Chen, Wen; Chen, Xudong

    2011-05-09

    In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed. © 2011 Optical Society of America

  18. Role of photonic angular momentum states in nonreciprocal diffraction from magneto-optical cylinder arrays

    Directory of Open Access Journals (Sweden)

    Tian-Jing Guo

    2014-07-01

    Full Text Available Optical eigenstates in a concentrically symmetric resonator are photonic angular momentum states (PAMSs with quantized optical orbital angular momentums (OAMs. Nonreciprocal optical phenomena can be obtained if we lift the degeneracy of PAMSs. In this article, we provide a comprehensive study of nonreciprocal optical diffraction of various orders from a magneto-optical cylinder array. We show that nonreciprocal diffraction can be obtained only for these nonzero orders. Role of PAMSs, the excitation of which is sensitive to the directions of incidence, applied magnetic field, and arrangement of the cylinders, are studied. Some interesting phenomena such as a dispersionless quasi-omnidirectional nonreciprocal diffraction and spikes associated with high-OAM PAMSs are present and discussed.

  19. Transferring diffractive optics from research to commercial applications: Part I - progress in the patent landscape

    Science.gov (United States)

    Brunner, Robert

    2013-12-01

    In the last 20 years, diffractive optics experienced a strong research interest and was in the center of many development projects in applied optics. To offer a side view for optical engineers, here, we discuss selected, business-related aspects of the current status of the transfer process to bring diffractive optics into commercial products. The contribution is divided into two parts. Here, in part I, we focus on the patent landscape of diffractive optics with a closer look on the temporal development and the distribution over main players. As an important result, currently, new strong patent activities are observed especially in the context of imaging systems. In the second part, the business volumes of selected market segments are discussed.

  20. Scattering and Diffraction of Electromagnetic Radiation: An Effective Probe to Material Structure

    Science.gov (United States)

    Xu, Yu-Lin

    2016-01-01

    Scattered electromagnetic waves from material bodies of different forms contain, in an intricate way, precise information on the intrinsic, geometrical and physical properties of the objects. Scattering theories, ever deepening, aim to provide dependable interpretation and prediction to the complicated interaction of electromagnetic radiation with matter. There are well-established multiple-scattering formulations based on classical electromagnetic theories. An example is the Generalized Multi-particle Mie-solution (GMM), which has recently been extended to a special version ? the GMM-PA approach, applicable to finite periodic arrays consisting of a huge number (e.g., >>106) of identical scattering centers [1]. The framework of the GMM-PA is nearly complete. When the size of the constituent unit scatterers becomes considerably small in comparison with incident wavelength, an appropriate array of such small element volumes may well be a satisfactory representation of a material entity having an arbitrary structure. X-ray diffraction is a powerful characterization tool used in a variety of scientific and technical fields, including material science. A diffraction pattern is nothing more than the spatial distribution of scattered intensity, determined by the distribution of scattering matter by way of its Fourier transform [1]. Since all linear dimensions entered into Maxwell's equations are normalized by wavelength, an analogy exists between optical and X-ray diffraction patterns. A large set of optical diffraction patterns experimentally obtained can be found in the literature [e.g., 2,3]. Theoretical results from the GMM-PA have been scrutinized using a large collection of publically accessible, experimentally obtained Fraunhofer diffraction patterns. As far as characteristic structures of the patterns are concerned, theoretical and experimental results are in uniform agreement; no exception has been found so far. Closely connected with the spatial distribution of

  1. Diffraction of stochastic electromagnetic fields by a hole in a thin film with real optical properties

    Science.gov (United States)

    Dorofeyev, Illarion

    2008-08-01

    The classical Kirchhoff theory of diffraction is extended to the case of real optical properties of a screen and its finite thickness. A spectral power density of diffracted electromagnetic fields by a hole in a thin film with real optical properties was calculated. The problem was solved by use of the vector Green theorems and related Green function of the boundary value problem. A spectral and spatial selectivity of the considered system was demonstrated. Diffracted patterns were calculated for the coherent and incoherent incident fields in case of holes array in a screen of perfect conductivity.

  2. Diffraction of stochastic electromagnetic fields by a hole in a thin film with real optical properties

    International Nuclear Information System (INIS)

    Dorofeyev, Illarion

    2008-01-01

    The classical Kirchhoff theory of diffraction is extended to the case of real optical properties of a screen and its finite thickness. A spectral power density of diffracted electromagnetic fields by a hole in a thin film with real optical properties was calculated. The problem was solved by use of the vector Green theorems and related Green function of the boundary value problem. A spectral and spatial selectivity of the considered system was demonstrated. Diffracted patterns were calculated for the coherent and incoherent incident fields in case of holes array in a screen of perfect conductivity

  3. Interference of diffraction and transition radiation and its application as a beam divergence diagnostic

    Directory of Open Access Journals (Sweden)

    R. B. Fiorito

    2006-05-01

    Full Text Available We have observed the interference of optical diffraction radiation (ODR and optical transition radiation (OTR produced by the interaction of a relativistic electron beam with a micromesh foil and a mirror. The production of forward directed ODR from electrons passing through the holes and wires of the mesh and their separate interactions with backward OTR from the mirror are analyzed with the help of a simulation code. By careful choice of the micromesh properties, mesh-mirror spacing, observation wavelength, and filter band pass, the interference of the ODR produced from the unperturbed electrons passing through the open spaces of the mesh and OTR from the mirror are observable above a broad incoherent background from interaction of the heavily scattered electrons passing through the mesh wires. These interferences (ODTRI are sensitive to the beam divergence and can be used to directly diagnose this parameter. We compare experimental divergence values obtained using ODTRI, conventional OTRI, for the case when front foil scattering is negligible, and computed values obtained from transport code calculations and multiple screen beam size measurements. We obtain good agreement in all cases.

  4. Pattern formation without diffraction matching in optical parametric oscillators with a metamaterial.

    Science.gov (United States)

    Tassin, Philippe; Van der Sande, Guy; Veretennicoff, Irina; Kockaert, Pascal; Tlidi, Mustapha

    2009-05-25

    We consider a degenerate optical parametric oscillator containing a left-handed material. We show that the inclusion of a left-handed material layer allows for controlling the strength and sign of the diffraction coefficient at either the pump or the signal frequency. Subsequently, we demonstrate the existence of stable dissipative structures without diffraction matching, i.e., without the usual relationship between the diffraction coefficients of the signal and pump fields. Finally, we investigate the size scaling of these light structures with decreasing diffraction strength.

  5. Quantum diffraction and interference of spatially correlated photon pairs and its Fourier-optical analysis

    International Nuclear Information System (INIS)

    Shimizu, Ryosuke; Edamatsu, Keiichi; Itoh, Tadashi

    2006-01-01

    We present one- and two-photon diffraction and interference experiments involving parametric down-converted photon pairs. By controlling the divergence of the pump beam in parametric down-conversion, the diffraction-interference pattern produced by an object changes from a quantum (perfectly correlated) case to a classical (uncorrelated) one. The observed diffraction and interference patterns are accurately reproduced by Fourier-optical analysis taking into account the quantum spatial correlation. We show that the relation between the spatial correlation and the object size plays a crucial role in the formation of both one- and two-photon diffraction-interference patterns

  6. Negative optical spin torque wrench of a non-diffracting non-paraxial fractional Bessel vortex beam

    International Nuclear Information System (INIS)

    Mitri, F.G.

    2016-01-01

    An absorptive Rayleigh dielectric sphere in a non-diffracting non-paraxial fractional Bessel vortex beam experiences a spin torque. The axial and transverse radiation spin torque components are evaluated in the dipole approximation using the radiative correction of the electric field. Particular emphasis is given on the polarization as well as changing the topological charge α and the half-cone angle of the beam. When α is zero, the axial spin torque component vanishes. However, when α becomes a real positive number, the vortex beam induces left-handed (negative) axial spin torque as the sphere shifts off-axially from the center of the beam. The results show that a non-diffracting non-paraxial fractional Bessel vortex beam is capable of inducing a spin reversal of an absorptive Rayleigh sphere placed arbitrarily in its path. Potential applications are yet to be explored in particle manipulation, rotation in optical tweezers, optical tractor beams, and the design of optically-engineered metamaterials to name a few areas. - Highlights: • Optical nondiffracting nonparaxial fractional Bessel vortex beam is considered. • Negative spin torque on an absorptive dielectric Rayleigh sphere is predicted numerically. • Negative spin torque occurs as the sphere departs from the center of the beam.

  7. Nanostructured diffractive optical devices for soft X-ray microscopes

    CERN Document Server

    Hambach, D; Schneider, G

    2001-01-01

    The new transmission X-ray microscope (TXM) installed at the BESSY II electron storage ring uses an off-axis transmission zone plate (OTZ) as diffractive and focusing element of the condenser-monochromator setup. A high resolution micro-zone plate (MZP) forms a magnified image on a CCD-detector. Both, the OTZ with an active area of up to 24 mm sup 2 and the MZP with zone widths as small as 25 nm are generated by a process including electron beam lithography (EBL), dry etching and subsequent electroplating of nickel on top of silicon membrane substrates with about 100-150 nm thickness. The combination of a larger zone width and the usage of nickel zone structures allows to increase the diffraction efficiency of the condenser element at least by a factor of 3 compared to the earlier used KZP7 condenser zone plate in the TXM at BESSY I. Groove diffraction efficiencies of 21.6% and 14.7% were measured for MZP objectives with 40 and 25 nm outermost zone width, respectively.

  8. Effect of substrate material selection on polychromatic integral diffraction efficiency for multilayer diffractive optics in oblique incident situation

    Science.gov (United States)

    Zhang, Bo; Cui, Qingfeng; Piao, Mingxu

    2018-05-01

    The effect of substrate material selection for multilayer diffractive optical elements (MLDOEs) on polychromatic integral diffraction efficiency (PIDE) is studied in the oblique incident situation. A mathematical model of substrate material selection is proposed to obtain the high PIDE with large incident angle. The extended expression of the microstructure heights with consideration of incident angle is deduced to calculate the PIDE difference Δ η bar(λ) for different substrate material combinations. The smaller value of Δ η bar(λ) indicates the more optimal substrate material combination in a wide incident angle range. Based on the deduced mathematical model, different MLDOEs are analyzed in visible and infrared wavebands. The results show that the three-layer DOEs can be applied in larger incident angle situation than the double-layer DOEs in visible waveband. When the two substrate materials are the same, polycarbonate (PC) is more reasonable than poly(methyl methacrylate) (PMMA) as the middle filling optical material for the three-layer DOEs. In the infrared waveband, the PIDE decreases in the LWIR are obviously smaller than that in the MWIR for the same substrate material combination, and the PIDE cannot be calculated when the incident angle larger than critical angle. The analysis results can be used to guide the hybrid optical system design with MLDOEs.

  9. Simultaneous Replication of both Refractive and Diffractive Optical Components using Electroformed Tools and Injection Moulding

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Christensen, Thomas R.

    2003-01-01

    This research project has demonstrated that with carefully selected processes it is possible to fabricate tools for injection moulding of both diffractive and refractive optical components. The fabrication procedure is based on an aluminium disc on which selected optical components (gratings and ...

  10. Development and applications of diffractive optical security devices for banknotes and high value documents

    Science.gov (United States)

    Drinkwater, John K.; Holmes, Brian W.; Jones, Keith A.

    2000-04-01

    Embossed holograms and othe rdiffractive optically variable devices are increasingly familiar security items on plastic cards, banknotes, securyt documetns and on branded gods and media to protect against counterfeit, protect copyright and to evidence tamper. This paper outlines some of the diffractive optical seuryt and printed security develoepd for this rapidly growing field and provides examles of some current security applications.

  11. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  12. Radiation effects on optical data transmission systems

    International Nuclear Information System (INIS)

    Leskovar, B.

    1989-01-01

    The state of the art of optical transmitters, low loss fiber waveguides and receivers in both steady state and pulsed radiation environments is reviewed and summarized. Emphasis is placed on the effects of irradiation on the performance of light emitting and laser diodes, optical fiber waveguides and photodiodes. The influence of radiation-induced attenuation of optical fibers due to total dose, dose rate, time after irradiation, temperature, radiation history, photobleaching, OH and impurity content, dopant type and concentration is described. The performance of candidate components of the transmission system intended for deployment in the Superconducting Super Collider Detector and primary beam tunnel nuclear environment is discussed

  13. Hybrid diffractive-refractive optical system design of head-mounted display for augmented reality

    Science.gov (United States)

    Zhang, Huijuan

    2005-02-01

    An optical see-through head-mounted display for augmented reality is designed in this paper. Considering the factors, such as the optical performance, the utilization ratios of energy of real world and virtual world, the feelings of users when he wears it and etc., a structure of the optical see-through is adopted. With the characteristics of the particular negative dispersive and the power of realizing random-phase modulation, the diffractive surface is helpful for optical system of reducing weight, simplifying structure and etc., and a diffractive surface is introduced in our optical system. The optical system with 25 mm eye relief, 12 mm exit pupil and 20° (H)x15.4° (V) field-of-view is designed. The utilization ratios of energy of real world and virtual world are 1/4 and 1/2, respectively. The angular resolution of display is 0.27 mrad and it less than that of the minimum of human eyes. The diameter of this system is less than 46mm, and it applies the binocular. This diffractive-refractive optical system of see-through head-mounted display not only satisfies the demands of user"s factors in structure, but also with high resolution, very small chromatic aberration and distortion, and satisfies the need of augmented reality. In the end, the parameters of the diffractive surface are discussed.

  14. Asymmetric diffraction by atomic gratings with optical PT symmetry in the Raman-Nath regime

    Science.gov (United States)

    Shui, Tao; Yang, Wen-Xing; Liu, Shaopeng; Li, Ling; Zhu, Zhonghu

    2018-03-01

    We propose and analyze an efficient scheme for the lopsided Raman-Nath diffraction of one-dimensional (1 D ) and two-dimensional (2 D ) atomic gratings with periodic parity-time (PT )-symmetric refractive index. The atomic grating is constructed by the cold-atomic vapor with two isotopes of rubidium, which is driven by weak probe field and space-dependent control field. Using experimentally achievable parameters, we identify the conditions under which PT -symmetric refractive index allows us to observe the lopsided Raman-Nath diffraction phenomenon and improve the diffraction efficiencies beyond what is achievable in a conventional atomic grating. The nontrivial atomic grating is a superposition of an amplitude grating and a phase grating. It is found that the lopsided Raman-Nath diffraction at the exceptional point (EP) of PT -symmetric grating originates from constructive and destructive interferences between the amplitude and phase gratings. Furthermore, we show that the PT -phase transition from unbroken to broken PT -symmetric regimes can modify the asymmetric distribution of the diffraction spectrum and that the diffraction efficiencies in the non-negative diffraction orders can be significantly enhanced when the atomic grating is pushed into a broken PT -symmetric phase. In addition, we also analyze the influence of the grating thickness on the diffraction spectrum. Our scheme may provide the possibility to design a gain-beam splitter with tunable splitting ratio and other optical components in integrated optics.

  15. Quantum Optics, Diffraction Theory, and Elementary Particle Physics

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Physical optics has expanded greatly in recent years. Though it remains part of the ancestry of elementary particle physics, there are once again lessons to be learned from it. I shall discuss several of these, including some that have emerged at CERN and Brookhaven.

  16. Moessbauer radiation dynamical diffraction in crystals being subjected to the action of external variable fields

    International Nuclear Information System (INIS)

    Baryshevskii, V.G.; Skadorov, V.V.

    1986-01-01

    A dynamical theory is developed of the Moessbauer radiation diffraction by crystals being subjected to an variable external field action. Equations describing the dynamical diffraction by nonstationary crystals are obtained. It is shown that the resonant interaction between Moessbauer radiation and shift field induced in the crystal by a variable external field giving rise to an effective conversion of the incident wave into a wave with changed frequency. (author)

  17. Holographic diffraction gratings as laser radiation protection filters

    International Nuclear Information System (INIS)

    Pantelic, D.; Pantelic, G.

    2006-01-01

    Holographic volume diffraction gratings are used as attenuation filters, due to their selective spectral transmission. They can be tailored to reflect or transmit narrow spectral ranges by adjusting spatial frequency of Bragg grating in carefully chosen photosensitive materials, like silver-halide emulsion or di-chromated gelatin layers. If properly recorded and chemically processed, resulting gratings can significantly attenuate light at wavelengths corresponding to various laser spectral lines. Thus, they can be used as filters in laser protection goggles. We analyze the characteristics of Bragg gratings necessary to obtain high attenuation coefficients. Also, their angular selectivity is taken into account and corresponding experimental conditions are investigated. Although di-chromated gelatin seems to be almost ideal material, due to its almost 100% diffraction efficiency, environmental stability is poor (degradation under humid environment), thus making its practical usage difficult. Thus, we have analyzed alternative materials like di-chromated pullulan, which is stable under normal environmental conditions (without drop in diffraction efficiency after prolonged exposure to humidity). Pullulan is polymer (polysaccharide) of biologic origin produced by certain bacteria. If doped with chromium ions it becomes photosensitive, enabling recording of diffraction gratings with spatial frequency of more than 3000 lines/mm. Material is chemically processed by mixture of isopropyl alcohol and water. Both thick and thin layers can be produced by gravity settling. Spectral properties of resulting gratings are analyzed, showing that they can significantly attenuate laser light of particular wavelength, depending of grating period and its slant angle. (authors)

  18. Negative optical spin torque wrench of a non-diffracting non-paraxial fractional Bessel vortex beam

    Science.gov (United States)

    Mitri, F. G.

    2016-10-01

    An absorptive Rayleigh dielectric sphere in a non-diffracting non-paraxial fractional Bessel vortex beam experiences a spin torque. The axial and transverse radiation spin torque components are evaluated in the dipole approximation using the radiative correction of the electric field. Particular emphasis is given on the polarization as well as changing the topological charge α and the half-cone angle of the beam. When α is zero, the axial spin torque component vanishes. However, when α becomes a real positive number, the vortex beam induces left-handed (negative) axial spin torque as the sphere shifts off-axially from the center of the beam. The results show that a non-diffracting non-paraxial fractional Bessel vortex beam is capable of inducing a spin reversal of an absorptive Rayleigh sphere placed arbitrarily in its path. Potential applications are yet to be explored in particle manipulation, rotation in optical tweezers, optical tractor beams, and the design of optically-engineered metamaterials to name a few areas.

  19. Characterization of radiation within the optical region

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, H [Stuttgart Univ. (TH) (Germany, F.R.). Inst. fuer Physikalische Elektronik

    1977-04-01

    The notions which are used for the characterization of radiation within the optical region of the spectrum (quantities, units) and their temporal and geometric relations have been arranged synoptically. Quantities of the international system (SI-System) are emphasized.

  20. Radiation resistance of optical fibers, (10)

    International Nuclear Information System (INIS)

    Tsunoda, Tsunemi; Ara, Katsuyuki; Morimoto, Naoki; Sanada, Kazuo; Inada, Koichi.

    1991-01-01

    Optical fibers have many excellent characteristics such as the light weight of the material, insulation, the noninductivity of electromagnetic interference noise, the wide band of signal transmission, and small loss. Also in the field of atomic energy, the utilization of optical fibers is positively expanded, and the research on the method of application and so on has been advanced. However in optical fibers, there is the problem that color centers are formed at the relatively low level of radiation, and they are colored. Accordingly, for effectively utilizing optical fibers in radiation environment, it is indispensable to improve their radiation resistance. For the purpose of solving this problem, the authors have carried out the basic research on the effect that radiation exerts to optical fibers and the development of the optical fibers having excellent radiation resistance. For the purpose of expanding the range of application of GeO 2 -doped silica core fibers including GI type in radiation regions, the transmission characteristics of the fibers during irradiation were examined by using the Cl content as the parameter. Therefore, the results are reported. The fibers put to the test, the testing method and the results are described. (K.I.)

  1. Transverse energy circulation and the edge diffraction of an optical vortex beam.

    Science.gov (United States)

    Bekshaev, Aleksandr Ya; Mohammed, Kadhim A; Kurka, Ivan A

    2014-04-01

    Edge diffraction of a circular Laguerre-Gaussian beam represents an example of the optical vortex symmetry breakdown in which the hidden "vortex" energy circulation is partially transformed into the visible "asymmetry" form. The diffracted beam evolution is studied in terms of the irradiance moments and the moment-based parameters. In spite of the limited applicability of the moment-based formalism, we show that the "vortex" and "asymmetry" parts of the orbital angular momentum can still be reasonably defined for the hard-edge diffracted beams and retain their physical role of quantifying the corresponding forms of the transverse energy circulation.

  2. Optical fiber-applied radiation detection system

    International Nuclear Information System (INIS)

    Nishiura, Ryuichi; Uranaka, Yasuo; Izumi, Nobuyuki

    2001-01-01

    A technique to measure radiation by using plastic scintillation fibers doped radiation fluorescent (scintillator) to plastic optical fiber for a radiation sensor, was developed. The technique contains some superiority such as high flexibility due to using fibers, relatively easy large area due to detecting portion of whole of fibers, and no electromagnetic noise effect due to optical radiation detection and signal transmission. Measurable to wide range of and continuous radiation distribution along optical fiber cable at a testing portion using scintillation fiber and flight time method, the optical fiber-applied radiation sensing system can effectively monitor space radiation dose or apparatus operation condition monitoring. And, a portable type scintillation optical fiber body surface pollution monitor can measure pollution concentration of radioactive materials attached onto body surface by arranging scintillation fiber processed to a plate with small size and flexibility around a man to be tested. Here were described on outline and fundamental properties of various application products using these plastic scintillation fiber. (G.K.)

  3. Radiative properties of optical board embedded with optical black holes

    International Nuclear Information System (INIS)

    Qiu, J.; Liu, L.H.; Hsu, P.-F.

    2011-01-01

    Unique radiative properties, such as wavelength-selective transmission or absorption, have been intensively studied. Historically, geometries for wavelength-selective of light absorption were developed based on metallic periodical structures, which were only applied in the case of TM wave incidence due to the excitation of surface plasmons. In this paper, we develop an alternative approach to selective wavelength of light absorption (both TE and TM waves), based on an optical board periodical embedded with optical black holes. Numerical work was carried out to study such structure's radiative properties within the wavelength range of 1-100 μm. The electromagnetic wave transmission through such a structure is predicted by solving Maxwell's equations using the finite-difference time-domain (FDTD) method. Spectral absorptance varies with the period of optical black holes. When the incidence wavelength is much larger than the inner core radius, most of the light energy will be transmitted through the inner core. Otherwise, the energy will be mainly absorbed. Numerical results of the radiative properties of the optical board with different incidence wavelengths are also obtained. The effect of the oblique incidence wave is investigated. This study helps us gain a better understanding of the radiative properties of an optical board embedded with optical black holes and develop an alternative approach to selective light absorption.

  4. Metrology of reflection optics for synchrotron radiation

    International Nuclear Information System (INIS)

    Takacs, P.Z.

    1985-09-01

    Recent years have seen an almost explosive growth in the number of beam lines on new and existing synchrotron radiation facilities throughout the world. The need for optical components to utilize the unique characteristics of synchrotron radiation has increased accordingly. Unfortunately, the technology to manufacture and measure the large, smooth, exotic optical surfaces required to focus and steer the synchrotron radiation beam has not progressed as rapidly as the operational demands on these components. Most companies do not wish to become involved with a project that requires producing a single, very expensive, aspheric optic with surface roughness and figure tolerances that are beyond their capabilities to measure. This paper will review some of the experiences of the National Synchrotron Light Source in procuring grazing incidence optical components over the past several years. We will review the specification process - how it is related to the function of the optic, and how it relates to the metrology available during the manufacturing process and after delivery to the user's laboratory. We will also discuss practical aspects of our experience with new technologies, such as single point diamond turning of metal mirrors and the use of SiC as a mirror material. Recent advances in metrology instrumentation have the potential to move the measurement of surface figure and finish from the research laboratory into the optical shop, which should stimulate growth and interest in the manufacturing of optics to meet the needs of the synchrotron radiation user community

  5. Radiation distribution sensor with optical fibers for high radiation fields

    International Nuclear Information System (INIS)

    Takada, Eiji; Kimura, Atsushi; Hosono, Yoneichi; Takahashi, Hiroyuki; Nakazawa, Masaharu

    1999-01-01

    Radiation distribution sensors with their feasibilities have been described in earlier works. However, due to large radiation induced transmission losses in optical fibers, especially in the visible wavelength region, it has been difficult to apply these techniques to high radiation fields. In this study, we proposed a new concept of optical fiber based radiation distribution measurements with near infrared (IR) emission. Near IR scintillators were attached to the ends of optical fibers, where the fibers were bundled and connected to an N-MOS line sensor or a cooled CCD camera. From the measurements of each area density, the radiation levels at the positions of the scintillators can be known. The linearity between the gamma dose rate at each scintillator and the registered counts has been examined. For correcting the radiation induced loss effects, we applied the Optical Time Domain Reflectometry technique to measure the loss distribution and from the results, a possibility for correction of the loss effect has been demonstrated. The applicable dose rate range was evaluated to be from 0.1 to 10 3 Gy/h. This system can be a promising tool as a flexible dose rate distribution monitor in radiation facilities like nuclear plants and accelerator facilities. (author)

  6. Bragg diffraction of fermions at optical potentials; Braggbeugung von Fermionen an optischen Potentialen

    Energy Technology Data Exchange (ETDEWEB)

    Deh, Benjamin

    2008-10-27

    This thesis describes the Bragg diffraction of ultracold fermions at an optical potential. A moving optical lattice was created, by overlaying two slightly detuned lasers. Atoms can be diffracted at this lattice if the detuning fulfills the Bragg condition for resting atoms. This Bragg diffraction is analyzed systematically in this thesis. To this end Rabi oscillations between the diffraction states were driven, as well in the weakly interacting Bragg regime, as in the strongly interacting Kapitza-Dirac regime. Simulations, based on a driven two-, respectively multilevel-system describe the observed effects rather well. Furthermore, the temporal evolution of the diffracted states in the magnetic trapping potential was studied. The anharmonicity of the trap in use and the scattering cross section for p-wave collisions in a {sup 6}Li system was determined from the movement of these states. Moreover the momentum distribution of the fermions was measured with Bragg spectroscopy and first signs of Fermi degeneracy were found. Finally an interferometer with fermions was build, exhibiting a coherence time of more than 100 {mu}s. With this, the possibility for measurement and manipulation of ultracold fermions with Bragg diffraction could bee shown. (orig.)

  7. Evanescent Properties of Optical Diffraction from 2-Dimensional Hexagonal Photonic Crystals and Their Sensor Applications.

    Science.gov (United States)

    Liao, Yu-Yang; Chen, Yung-Tsan; Chen, Chien-Chun; Huang, Jian-Jang

    2018-04-03

    The sensitivity of traditional diffraction grating sensors is limited by the spatial resolution of the measurement setup. Thus, a large space is required to improve sensor performance. Here, we demonstrate a compact hexagonal photonic crystal (PhC) optical sensor with high sensitivity. PhCs are able to diffract optical beams to various angles in azimuthal space. The critical wavelength that satisfies the phase matching or becomes evanescent was used to benchmark the refractive index of a target analyte applied on a PhC sensor. Using a glucose solution as an example, our sensor demonstrated very high sensitivity and a low limit of detection. This shows that the diffraction mechanism of hexagonal photonic crystals can be used for sensors when compact size is a concern.

  8. Optical necklaces generated by the diffraction on a stack of dielectric wedges

    Energy Technology Data Exchange (ETDEWEB)

    Izdebskaya, Yana [Nonlinear Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Physics, V.I. Vernandsky Taurida National University, Simferopol 95007, Crimea (Ukraine)], E-mail: yvi124@rsphysse.anu.edu.au

    2008-05-19

    We demonstrate that the regular ring-shaped arrays of Gaussian beams, or optical necklaces, can be generated using diffraction on a stack of dielectric wedges. A condition for self-similarity and structural stability of the beams has been derived and shows good comparison with experimental data.

  9. Geometrical Reasoning in Wave Situations: The Case of Light Diffraction and Coherent Illumination Optical Imaging

    Science.gov (United States)

    Maurines, Laurence

    2010-01-01

    This particular study is part of a research programme on the difficulties encountered by students when learning about wave phenomena in a three-dimensional medium in the absence or presence of obstacles. It focuses on how students reason in situations in which wave optics need to be used: diffraction of light by an aperture, imaging in the…

  10. Diffraction, self-focusing, and the geometrical optics limit in laser produced plasmas

    International Nuclear Information System (INIS)

    Marchand, R.; Rankin, R.; Capjack, C.E.; Birnboim, A.

    1987-01-01

    The effect of diffraction on the self-modulation of an intense laser beam in an initially uniform hydrogen plasma is investigated. A formalism is used in which the diffraction term in the paraxial wave equation can be arbitrarily reduced by the use of a weight factor iota. In the limit where iota approaches zero, it is shown that the paraxial wave equation correctly reduces to the geometrical optics limit and that the problem then becomes formally equivalent to solving the ray-tracing equations. When iota = 1, the paraxial wave equation takes its usual form and diffraction is fully accounted for. This formalism is applied to the simulation of self-modulation of an intense laser beam in a hydrogen plasma, for which diffraction is shown to be significant

  11. Ray optics for diffraction: a useful paradox in a path integral context

    International Nuclear Information System (INIS)

    Schulman, L.S.

    1984-01-01

    Geometrical diffraction theory uses ray tracing techniques to calculate diffraction and other properties of the electromagnetic field generally considered characteristically wave like. The author studies this dualism of the classical electromagnetic field so as to distinguish those aspects of quantum dualism that arise simply as properties of oscillatory integrals and those that may have deeper origins. By a series of transformations the solutions of certain optics problems are reduced to the evaluation of a Feynman path integral and the known semiclassical approximations for the path integral provide a justification for the geometrical diffraction theory. Particular attention is paid to the problem of edge diffraction and for a half plane barrier a closed form solution is obtained. A classical variational principle for barrier penetration is also presented. (Auth.)

  12. Diffraction-unlimited optical imaging of unstained living cells in liquid by electron beam scanning of luminescent environmental cells.

    Science.gov (United States)

    Miyazaki, Hideki T; Kasaya, Takeshi; Takemura, Taro; Hanagata, Nobutaka; Yasuda, Takeshi; Miyazaki, Hiroshi

    2013-11-18

    An environmental cell with a 50-nm-thick cathodoluminescent window was attached to a scanning electron microscope, and diffraction-unlimited near-field optical imaging of unstained living human lung epithelial cells in liquid was demonstrated. Electrons with energies as low as 0.8 - 1.2 kV are sufficiently blocked by the window without damaging the specimens, and form a sub-wavelength-sized illumination light source. A super-resolved optical image of the specimen adhered to the opposite window surface was acquired by a photomultiplier tube placed below. The cells after the observation were proved to stay alive. The image was formed by enhanced dipole radiation or energy transfer, and features as small as 62 nm were resolved.

  13. A method of combining STEM image with parallel beam diffraction and electron-optical conditions for diffractive imaging

    International Nuclear Information System (INIS)

    He Haifeng; Nelson, Chris

    2007-01-01

    We describe a method of combining STEM imaging functionalities with nanoarea parallel beam electron diffraction on a modern TEM. This facilitates the search for individual particles whose diffraction patterns are needed for diffractive imaging or structural studies of nanoparticles. This also lays out a base for 3D diffraction data collection

  14. 15x optical zoom and extreme optical image stabilisation: diffraction limited integral field spectroscopy with the Oxford SWIFT spectrograph

    Science.gov (United States)

    Tecza, Matthias; Thatte, Niranjan; Clarke, Fraser; Lynn, James; Freeman, David; Roberts, Jennifer; Dekany, Richard

    2012-09-01

    When commissioned in November 2008 at the Palomar 200 inch Hale Telescope, the Oxford SWIFT I and z band integral field spectrograph, fed by the adaptive optics system PALAO, provided a wide (3×) range of spatial resolutions: three plate scales of 235 mas, 160 mas, and 80 mas per spaxel over a contiguous field-of-view of 89×44 pixels. Depending on observing conditions and guide star brightness we can choose a seeing limited scale of 235 mas per spaxel, or 160 mas and 80 mas per spaxel for very bright guide star AO with substantial increase of enclosed energy. Over the last two years PALAO was upgraded to PALM-3000: an extreme, high-order adaptive optics system with two deformable mirrors with more than 3000 actuators, promising diffraction limited performance in SWIFT's wavelength range. In order to take advantage of this increased spatial resolution we upgraded SWIFT with new pre-optics allowing us to spatially Nyquist sample the diffraction limited PALM-3000 point spread function with 16 mas resolution, reducing the spaxel scale by another factor of 5×. We designed, manufactured, integrated and tested the new pre-optics in the first half of 2011 and commissioned it in December 2011. Here we present the opto-mechanical design and assembly of the new scale changing optics, as well as laboratory and on-sky commissioning results. In optimal observing conditions we achieve substantial Strehl ratios, delivering the near diffraction limited spatial resolution in the I and z bands.

  15. Comparative study of structural properties of trehalose water solutions by neutron diffraction, synchrotron radiation and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Cesaro, A.; Magazu, V.; Migliardo, F.; Sussich, F.; Vadala, M

    2004-07-15

    Neutron diffraction measurements combined with H/D substitution have been performed on trehalose aqueous solutions as a function of temperature and concentration by using the SANDALS diffractometer at ISIS Facility (UK). The findings point out a high capability of trehalose to strongly affect the tetrahedral hydrogen bond network of water. The neutron diffraction results are also compared with simulation and experimental data obtained by synchrotron radiation on the phospholipid bilayer membranes (DPPC)/trehalose/H{sub 2}O ternary system.

  16. Polarization control of non-diffractive helical optical beams through subwavelength metallic apertures

    International Nuclear Information System (INIS)

    Lombard, E; Genet, C; Ebbesen, T W; Drezet, A

    2010-01-01

    We demonstrate experimentally a simple method for preparing non-diffractive vectorial optical beams that can display wave-front helicity. This method is based on space-variant modifications of the polarization of an optical beam transmitted through subwavelength annular rings perforating opaque metal films. We show how the description of the optical properties of such structures must account for the vectorial character of the polarization and how, in turn, these properties can be controlled by straightforward sequences of preparation and analysis of polarization states.

  17. Measurement of 3D refractive index distribution by optical diffraction tomography

    Science.gov (United States)

    Chi, Weining; Wang, Dayong; Wang, Yunxin; Zhao, Jie; Rong, Lu; Yuan, Yuanyuan

    2018-01-01

    Optical Diffraction Tomography (ODT), as a novel 3D imaging technique, can obtain a 3D refractive index (RI) distribution to reveal the important optical properties of transparent samples. According to the theory of ODT, an optical diffraction tomography setup is built based on the Mach-Zehnder interferometer. The propagation direction of object beam is controlled by a 2D translation stage, and 121 holograms based on different illumination angles are recorded by a Charge-coupled Device (CCD). In order to prove the validity and accuracy of the ODT, the 3D RI profile of microsphere with a known RI is firstly measured. An iterative constraint algorithm is employed to improve the imaging accuracy effectively. The 3D morphology and average RI of the microsphere are consistent with that of the actual situation, and the RI error is less than 0.0033. Then, an optical element fabricated by laser with a non-uniform RI is taken as the sample. Its 3D RI profile is obtained by the optical diffraction tomography system.

  18. Transferring diffractive optics from research to commercial applications: Part II - size estimations for selected markets

    Science.gov (United States)

    Brunner, Robert

    2014-04-01

    In a series of two contributions, decisive business-related aspects of the current process status to transfer research results on diffractive optical elements (DOEs) into commercial solutions are discussed. In part I, the focus was on the patent landscape. Here, in part II, market estimations concerning DOEs for selected applications are presented, comprising classical spectroscopic gratings, security features on banknotes, DOEs for high-end applications, e.g., for the semiconductor manufacturing market and diffractive intra-ocular lenses. The derived market sizes are referred to the optical elements, itself, rather than to the enabled instruments. The estimated market volumes are mainly addressed to scientifically and technologically oriented optical engineers to serve as a rough classification of the commercial dimensions of DOEs in the different market segments and do not claim to be exhaustive.

  19. Observation of parametric X-ray radiation in an anomalous diffraction region

    Energy Technology Data Exchange (ETDEWEB)

    Alexeyev, V.I., E-mail: vial@x4u.lebedev.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Eliseyev, A.N., E-mail: elisseev@pluton.lpi.troitsk.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Irribarra, E., E-mail: esteban.irribarra@epn.edu.ec [Escuela Politécnica Nacional, Ladrón de Guevara E11-253, Quito (Ecuador); Kishin, I.A., E-mail: ivan.kishin@mail.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Kubankin, A.S., E-mail: kubankin@bsu.edu.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation); Nazhmudinov, R.M., E-mail: fizeg@bk.ru [P.N. Lebedev Physical Institute RAS, 53 Leninskiy prospect, Moscow (Russian Federation); Belgorod National Research University, 85 Pobedy st., Belgorod (Russian Federation)

    2016-08-19

    A new possibility to expand the energy region of diffraction processes based on the interaction of relativistic charged particles with crystalline structures is presented. Diffracted photons related to parametric X-ray radiation produced by relativistic electrons are detected below the low energy threshold for the X-ray diffraction mechanism in crystalline structures for the first time. The measurements were performed during the interaction of 7 MeV electrons with a textured polycrystalline tungsten foil and a highly oriented pyrolytic graphite crystal. The experiment results are in good agreement with a developed model based on the PXR kinematical theory. The developed experimental approach can be applied to separate the contributions of real and virtual photons to the total diffracted radiation generated during the interaction of relativistic charged particles with crystalline targets. - Highlights: • Parametric X-ray radiation below the low energy threshold for diffraction of free X-rays. • Experimental separation of the contributions from different radiation mechanisms. • PXR from relativistic electrons in mosaic crystals and textured polycrystlas.

  20. Microscopy of biological sample through advanced diffractive optics from visible to X-ray wavelength regime.

    Science.gov (United States)

    Di Fabrizio, Enzo; Cojoc, Dan; Emiliani, Valentina; Cabrini, Stefano; Coppey-Moisan, Maite; Ferrari, Enrico; Garbin, Valeria; Altissimo, Matteo

    2004-11-01

    The aim of this report is to demonstrate a unified version of microscopy through the use of advanced diffractive optics. The unified scheme derives from the technical possibility of realizing front wave engineering in a wide range of electromagnetic spectrum. The unified treatment is realized through the design and nanofabrication of phase diffractive elements (PDE) through which wave front beam shaping is obtained. In particular, we will show applications, by using biological samples, ranging from micromanipulation using optical tweezers to X-ray differential interference contrast (DIC) microscopy combined with X-ray fluorescence. We report some details on the design and physical implementation of diffractive elements that besides focusing also perform other optical functions: beam splitting, beam intensity, and phase redistribution or mode conversion. Laser beam splitting is used for multiple trapping and independent manipulation of micro-beads surrounding a cell as an array of tweezers and for arraying and sorting microscopic size biological samples. Another application is the Gauss to Laguerre-Gauss mode conversion, which allows for trapping and transfering orbital angular momentum of light to micro-particles immersed in a fluid. These experiments are performed in an inverted optical microscope coupled with an infrared laser beam and a spatial light modulator for diffractive optics implementation. High-resolution optics, fabricated by means of e-beam lithography, are demonstrated to control the intensity and the phase of the sheared beams in x-ray DIC microscopy. DIC experiments with phase objects reveal a dramatic increase in image contrast compared to bright-field x-ray microscopy. Besides the topographic information, fluorescence allows detection of certain chemical elements (Cl, P, Sc, K) in the same setup, by changing the photon energy of the x-ray beam. (c) 2005 Wiley-Liss, Inc.

  1. The Gaussian beam mode analysis of classical phase aberrations in diffraction-limited optical systems

    Science.gov (United States)

    Trappe, Neil; Murphy, J. Anthony; Withington, Stafford

    2003-07-01

    Gaussian beam mode analysis (GBMA) offers a more intuitive physical insight into how light beams evolve as they propagate than the conventional Fresnel diffraction integral approach. In this paper we illustrate that GBMA is a computationally efficient, alternative technique for tracing the evolution of a diffracting coherent beam. In previous papers we demonstrated the straightforward application of GBMA to the computation of the classical diffraction patterns associated with a range of standard apertures. In this paper we show how the GBMA technique can be expanded to investigate the effects of aberrations in the presence of diffraction by introducing the appropriate phase error term into the propagating quasi-optical beam. We compare our technique to the standard diffraction integral calculation for coma, astigmatism and spherical aberration, taking—for comparison—examples from the classic text 'Principles of Optics' by Born and Wolf. We show the advantages of GBMA for allowing the defocusing of an aberrated image to be evaluated quickly, which is particularly important and useful for probing the consequences of astigmatism and spherical aberration.

  2. The Gaussian beam mode analysis of classical phase aberrations in diffraction-limited optical systems

    International Nuclear Information System (INIS)

    Trappe, Neil; Murphy, J Anthony; Withington, Stafford

    2003-01-01

    Gaussian beam mode analysis (GBMA) offers a more intuitive physical insight into how light beams evolve as they propagate than the conventional Fresnel diffraction integral approach. In this paper we illustrate that GBMA is a computationally efficient, alternative technique for tracing the evolution of a diffracting coherent beam. In previous papers we demonstrated the straightforward application of GBMA to the computation of the classical diffraction patterns associated with a range of standard apertures. In this paper we show how the GBMA technique can be expanded to investigate the effects of aberrations in the presence of diffraction by introducing the appropriate phase error term into the propagating quasi-optical beam. We compare our technique to the standard diffraction integral calculation for coma, astigmatism and spherical aberration, taking - for comparison - examples from the classic text 'Principles of Optics' by Born and Wolf. We show the advantages of GBMA for allowing the defocusing of an aberrated image to be evaluated quickly, which is particularly important and useful for probing the consequences of astigmatism and spherical aberration

  3. Fiber optics in high dose radiation fields

    International Nuclear Information System (INIS)

    Partin, J.K.

    1985-01-01

    A review of the behavior of state-of-the-art optical fiber waveguides in high dose (greater than or equal to 10 5 rad), steady state radiation fields is presented. The influence on radiation-induced transmission loss due to experimental parameters such as dose rate, total dose, irradiation history, temperature, wavelength, and light intensity, for future work in high dose environments are given

  4. Simulation study of transverse optical klystron radiation

    International Nuclear Information System (INIS)

    Xu Hongliang; Diao Caozheng; Liu Jinying; He Duohui; Jia Qika; Wang Xiangqi

    1997-01-01

    The radiation from a transverse optical klystron (TOK) is calculated by far field approximation equation and numerical integration, in which the effects of electron-beam emittance and energy spread are considered. Accurate electron-beam profiles have been experimentally determined and modeled by the Monte Carlo method. The calculated spectra illustrate the emittance of Hefei storage ring imposes on the spontaneous radiation of TOK

  5. Diffractive beam shaping, tracking and coupling for wave-guided optical waveguides (WOWs)

    DEFF Research Database (Denmark)

    Villangca, Mark Jayson; Bañas, Andrew Rafael; Aabo, Thomas

    2014-01-01

    techniques to create multiple focal spots that can be coupled into light manipulated WOWs. This is done by using a spatial light modulator to project the necessary phase to generate the multiple coupling light spots. We incorporate a diffractive setup in our Biophotonics Workstation (BWS) and demonstrate......We have previously proposed and demonstrated the targeted-light delivery capability of wave-guided optical waveguides (WOWs). The full strength of this structure-mediated paradigm can be harnessed by addressing multiple WOWs and manipulating them to work in tandem. We propose the use of diffractive...

  6. Ionizing radiation detector using multimode optical fibers

    International Nuclear Information System (INIS)

    Suter, J.J.; Poret, J.C.; Rosen, M.; Rifkind, J.M.

    1993-01-01

    An optical ionizing radiation detector, based on the attenuation of 850-nm light in 50/125-μm multimode fibers, is described. The detector is especially well suited for application on spacecraft because of its small design. The detection element consists of a section of coiled fibers that has been designed to strip higher-order optical modes. Cylindrical radiation shields with atomic numbers ranging from Z = 13 (aluminum too) Z = 82 (lead) were placed around the ionizing radiation detector so that the effectiveness of the detector could be measured. By exposing the shields and the detector to 1.25-MeV cobalt 60 radiation, the mass attenuation coefficients of the shields were measured. The detector is based on the phenomenon that radiation creates optical color centers in glass fibers. Electron spin resonance spectroscopy performed on the 50/125-μm fibers showed the presence of germanium oxide and phosphorus-based color centers. The intensity of these centers is directly related to the accumulated gamma radiation

  7. Ultrafast coherent diffractive imaging of nanoparticles using X-ray free-electron laser radiation

    International Nuclear Information System (INIS)

    Kassemeyer, Stephan

    2014-01-01

    Coherent diffractive imaging with X-ray free-electron lasers (X-FEL) promises high-resolution structure determination of single microscopic particles without the need for crystallization. The diffraction signal of small samples can be very weak, a difficulty that can not be countered by merely increasing the number of photons because the sample would be damaged by a high absorbed radiation dose. Traditional X-ray crystallography avoids this problem by bringing many sample particles into a periodic arrangement, which amplifies the individual signals while distributing the absorbed dose. Depending on the sample, however, crystallization can be very difficult or even impossible. This thesis presents algorithms for a new imaging approach using X-FEL radiation that works with single, non-crystalline sample particles. X-FELs can deliver X-rays with a peak brilliance many orders of magnitude higher than conventional X-ray sources, compensating for their weak interaction cross sections. At the same time, FELs can produce ultra-short pulses down to a few femtoseconds. In this way it is possible to perform ultra-fast imaging, essentially ''freezing'' the atomic positions in time and terminating the imaging process before the sample is destroyed by the absorbed radiation. This thesis primarily focuses on the three-dimensional reconstruction of single (and not necessarily crystalline) particles using coherent diffractive imaging at X-FELs: in order to extract three-dimensional information from scattering data, two-dimensional diffraction patterns from many different viewing angles must be combined. Therefore, the diffraction signal of many identical sample copies in random orientations is measured. The main result of this work is a globally optimal algorithm that can recover the sample orientations solely based on the diffraction signal, enabling three-dimensional imaging for arbitrary samples. The problem of finding three-dimensional orientations is

  8. Bent approximations to synchrotron radiation optics

    International Nuclear Information System (INIS)

    Heald, S.

    1981-01-01

    Ideal optical elements can be approximated by bending flats or cylinders. This paper considers the applications of these approximate optics to synchrotron radiation. Analytic and raytracing studies are used to compare their optical performance with the corresponding ideal elements. It is found that for many applications the performance is adequate, with the additional advantages of lower cost and greater flexibility. Particular emphasis is placed on obtaining the practical limitations on the use of the approximate elements in typical beamline configurations. Also considered are the possibilities for approximating very long length mirrors using segmented mirrors

  9. Diffraction and Smith-Purcell radiation on the hemispherical bulges in a metal plate

    Science.gov (United States)

    Syshchenko, V. V.; Larikova, E. A.; Gladkih, Yu. P.

    2017-12-01

    The radiation resulting from the uniform motion of a charged particle near a hemispheric bulge on a metal plane is considered. The description of the radiation process based on the method of images is developed for the case of non-relativistic particle and a perfectly conducting target. The spectral-angular and spectral densities of the diffraction radiation on the single bulge (as well as the Smith-Purcell radiation on the periodic string of bulges) are computed. The possibility of application of the developed approach to the case of relativistic incident particle is discussed.

  10. Zone-boundary optimization for direct laser writing of continuous-relief diffractive optical elements.

    Science.gov (United States)

    Korolkov, Victor P; Nasyrov, Ruslan K; Shimansky, Ruslan V

    2006-01-01

    Enhancing the diffraction efficiency of continuous-relief diffractive optical elements fabricated by direct laser writing is discussed. A new method of zone-boundary optimization is proposed to correct exposure data only in narrow areas along the boundaries of diffractive zones. The optimization decreases the loss of diffraction efficiency related to convolution of a desired phase profile with a writing-beam intensity distribution. A simplified stepped transition function that describes optimized exposure data near zone boundaries can be made universal for a wide range of zone periods. The approach permits a similar increase in the diffraction efficiency as an individual-pixel optimization but with fewer computation efforts. Computer simulations demonstrated that the zone-boundary optimization for a 6 microm period grating increases the efficiency by 7% and 14.5% for 0.6 microm and 1.65 microm writing-spot diameters, respectively. The diffraction efficiency of as much as 65%-90% for 4-10 microm zone periods was obtained experimentally with this method.

  11. Frequency Tuning of IR First-Overtone CO Laser Radiation by Diffraction Grating and Frequency Selective Output Couplers

    National Research Council Canada - National Science Library

    Ionin, Andre

    1999-01-01

    ...: The contractor will investigate, both experimentally and theoretically, the feasibility of frequency tuning the first overtone carbon monoxide laser radiation by the use of diffraction gratings...

  12. Fiber-optic dosimeters for radiation therapy

    Science.gov (United States)

    Li, Enbang; Archer, James

    2017-10-01

    According to the figures provided by the World Health Organization, cancer is a leading cause of death worldwide, accounting for 8.8 million deaths in 2015. Radiation therapy, which uses x-rays to destroy or injure cancer cells, has become one of the most important modalities to treat the primary cancer or advanced cancer. The newly developed microbeam radiation therapy (MRT), which uses highly collimated, quasi-parallel arrays of x-ray microbeams (typically 50 μm wide and separated by 400 μm) produced by synchrotron sources, represents a new paradigm in radiotherapy and has shown great promise in pre-clinical studies on different animal models. Measurements of the absorbed dose distribution of microbeams are vitally important for clinical acceptance of MRT and for developing quality assurance systems for MRT, hence are a challenging and important task for radiation dosimetry. On the other hand, during the traditional LINAC based radiotherapy and breast cancer brachytherapy, skin dose measurements and treatment planning also require a high spatial resolution, tissue equivalent, on-line dosimeter that is both economical and highly reliable. Such a dosimeter currently does not exist and remains a challenge in the development of radiation dosimetry. High resolution, water equivalent, optical and passive x-ray dosimeters have been developed and constructed by using plastic scintillators and optical fibers. The dosimeters have peak edge-on spatial resolutions ranging from 50 to 500 microns in one dimension, with a 10 micron resolution dosimeter under development. The developed fiber-optic dosimeters have been test with both LINAC and synchrotron x-ray beams. This work demonstrates that water-equivalent and high spatial resolution radiation detection can be achieved with scintillators and optical fiber systems. Among other advantages, the developed fiber-optic probes are also passive, energy independent, and radiation hard.

  13. Multifocus microscopy with precise color multi-phase diffractive optics applied in functional neuronal imaging.

    Science.gov (United States)

    Abrahamsson, Sara; Ilic, Rob; Wisniewski, Jan; Mehl, Brian; Yu, Liya; Chen, Lei; Davanco, Marcelo; Oudjedi, Laura; Fiche, Jean-Bernard; Hajj, Bassam; Jin, Xin; Pulupa, Joan; Cho, Christine; Mir, Mustafa; El Beheiry, Mohamed; Darzacq, Xavier; Nollmann, Marcelo; Dahan, Maxime; Wu, Carl; Lionnet, Timothée; Liddle, J Alexander; Bargmann, Cornelia I

    2016-03-01

    Multifocus microscopy (MFM) allows high-resolution instantaneous three-dimensional (3D) imaging and has been applied to study biological specimens ranging from single molecules inside cells nuclei to entire embryos. We here describe pattern designs and nanofabrication methods for diffractive optics that optimize the light-efficiency of the central optical component of MFM: the diffractive multifocus grating (MFG). We also implement a "precise color" MFM layout with MFGs tailored to individual fluorophores in separate optical arms. The reported advancements enable faster and brighter volumetric time-lapse imaging of biological samples. In live microscopy applications, photon budget is a critical parameter and light-efficiency must be optimized to obtain the fastest possible frame rate while minimizing photodamage. We provide comprehensive descriptions and code for designing diffractive optical devices, and a detailed methods description for nanofabrication of devices. Theoretical efficiencies of reported designs is ≈90% and we have obtained efficiencies of > 80% in MFGs of our own manufacture. We demonstrate the performance of a multi-phase MFG in 3D functional neuronal imaging in living C. elegans.

  14. First indication of the coherent unipolar diffraction radiation generated by relativistic electrons

    Science.gov (United States)

    Naumenko, G.; Shevelev, M.

    2018-05-01

    As is generally known, the integral of the electric field strength over all time for usual (bipolar) radiation is zero. The first demonstration of the possibility of unipolar radiation generation has been considered theoretically by Bessonov in 1981 [E.G. Bessonov, Zh. Eksp. Teor. Fiz. 80 (1981) 852]. According to this work, the unipolar radiation (or strange electromagnetic waves) is radiation for which the integral of the electric field strength over the entire duration of a pulse differs significantly from zero. Later, several theoretical papers devoted to this phenomenon have appeared in the literature, where authors investigated mainly synchrotron radiation. However, despite the critical interest, the experimental investigations ignored this effect. In this paper we present results of the first experimental investigation of the unipolar radiation generated by a relativistic electron beam. To detect the unipolar radiation the detector that is sensitive to the selected direction of the electric field strength has been elaborated and tested. We used a designed detector to observe the coherent backward diffraction radiation appearing when a bunched electron beam travels in the vicinity of a flat conductive target. The asymmetry of the electric field strength of the coherent backward diffraction radiation has been demonstrated.

  15. A new non intercepting beam size diagnostics using diffraction radiation from a Slit

    International Nuclear Information System (INIS)

    Castellano, M.

    1996-09-01

    A new non interpreting beam size diagnostic for high charge electron beams is presented. This diagnostics is based on the analysis of the angular distribution of the 'diffracted' transition radiation emitted by the beam when crossing a slit cut in metallic foil. It allows a resolution better then the radiation transverse formation zone. Numerical results based on the parameters of the TTF FEL beam are given as example

  16. Exact solution for four-order acousto-optic Bragg diffraction with arbitrary initial conditions.

    Science.gov (United States)

    Pieper, Ron; Koslover, Deborah; Poon, Ting-Chung

    2009-03-01

    An exact solution to the four-order acousto-optic (AO) Bragg diffraction problem with arbitrary initial conditions compatible with exact Bragg angle incident light is developed. The solution, obtained by solving a 4th-order differential equation, is formalized into a transition matrix operator predicting diffracted light orders at the exit of the AO cell in terms of the same diffracted light orders at the entrance. It is shown that the transition matrix is unitary and that this unitary matrix condition is sufficient to guarantee energy conservation. A comparison of analytical solutions with numerical predictions validates the formalism. Although not directly related to the approach used to obtain the solution, it was discovered that all four generated eigenvalues from the four-order AO differential matrix operator are expressed simply in terms of Euclid's Divine Proportion.

  17. Optical fiber applied to radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Junior, Francisco A.B.; Costa, Antonella L.; Oliveira, Arno H. de; Vasconcelos, Danilo C., E-mail: fanbra@yahoo.com.br, E-mail: antonella@nuclear.ufmg.br, E-mail: heeren@nuclear.ufmg.br, E-mail: danilochagas@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Departamento de Engenharia Nuclear

    2015-07-01

    In the last years, the production of optical fibers cables has make possible the development of a range of spectroscopic probes for in situ analysis performing beyond nondestructive tests, environmental monitoring, security investigation, application in radiotherapy for dose monitoring, verification and validation. In this work, a system using an optical fiber cable to light signal transmission from a NaI(Tl) radiation detector is presented. The innovative device takes advantage mainly of the optical fibers small signal attenuation and immunity to electromagnetic interference to application for radiation detection systems. The main aim was to simplify the detection system making it to reach areas where the conventional device cannot access due to its lack of mobility and external dimensions. Some tests with this innovative system are presented and the results stimulate the continuity of the researches. (author)

  18. Diffraction of a Gaussian laser beam by a straight edge leading to the formation of optical vortices and elliptical diffraction fringes

    Science.gov (United States)

    Zeylikovich, Iosif; Nikitin, Aleksandr

    2018-04-01

    The diffraction of a Gaussian laser beam by a straight edge has been studied theoretically and experimentally for many years. In this paper, we have experimentally observed for the first time the formation of the cusped caustic (for the Fresnel number F ≈ 100) in the shadow region of the straight edge, with the cusp placed near the center of the circular laser beam(λ = 0 . 65 μm) overlapped with the elliptical diffraction fringes. These fringes are originated at the region near the cusp of the caustic where light intensity is zero and the wave phase is singular (the optical vortex). We interpret observed diffraction fringes as a result of interference between the helical wave created by the optical vortex and cylindrical wave diffracted at the straight edge. We have theoretically revealed that the number of high contrast diffraction fringes observable in a shadow region is determined by the square of the diffracted angles in the range of spatial frequencies of the scattered light field in excellent agreement with experiments. The extra phase singularities with opposite charges are also observed along the shadow boundary as the fork-like diffraction fringes.

  19. X-ray diffraction studies of sucrose and sucrose irradiated with γ-radiation

    International Nuclear Information System (INIS)

    Prasad, Mahendra

    1981-01-01

    In order to understand and solve numerous problems related to sugar quality and its storage life, X-ray diffraction studies of sucrose and sucrose irradiated with γ-radiation have been made. It is observed that the interplanar spacing 'd' in irradiated sucrose is reduced indicating the partial damage of sucrose lattice. (author)

  20. At-wavelength interferometry of high-NA diffraction-limited EUV optics

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Kenneth A.; Naulleau, Patrick; Rekawa, Senajith; Denham, Paul; Liddle, J. Alexander; Anderson, Erik; Jackson, Keith; Bokor, Jeffrey; Attwood, David

    2003-08-01

    Recent advances in all-reflective diffraction-limited optical systems designed for extreme ultraviolet (EUV) lithography have pushed numerical aperture (NA) values from 0.1 to 0.3, providing Rayleigh resolutions of 27-nm. Worldwide, several high-NA EUV optics are being deployed to serve in the development of advanced lithographic techniques required for EUV lithography, including the creation and testing of new, high-resolution photoresists. One such system is installed on an undulator beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. Sub{angstrom}-accuracy optical testing and alignment techniques, developed for use with the previous generations of EUV lithographic optical systems, are being extended for use at high NA. Considerations for interferometer design and use are discussed.

  1. At-wavelength interferometry of high-NA diffraction-limited EUV optics

    International Nuclear Information System (INIS)

    Goldberg, Kenneth A.; Naulleau, Patrick; Rekawa, Senajith; Denham, Paul; Liddle, J. Alexander; Anderson, Erik; Jackson, Keith; Bokor, Jeffrey; Attwood, David

    2003-01-01

    Recent advances in all-reflective diffraction-limited optical systems designed for extreme ultraviolet (EUV) lithography have pushed numerical aperture (NA) values from 0.1 to 0.3, providing Rayleigh resolutions of 27-nm. Worldwide, several high-NA EUV optics are being deployed to serve in the development of advanced lithographic techniques required for EUV lithography, including the creation and testing of new, high-resolution photoresists. One such system is installed on an undulator beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. Sub(angstrom)-accuracy optical testing and alignment techniques, developed for use with the previous generations of EUV lithographic optical systems, are being extended for use at high NA. Considerations for interferometer design and use are discussed

  2. Modeling focusing characteristics of low Fnumber diffractive optical elements with continuous relief fabricated by laser direct writing.

    Science.gov (United States)

    Shan, Mingguang; Tan, Jiubin

    2007-12-10

    A theoretical model is established using Rayleigh-Sommerfeld diffraction theory to describe the diffraction focusing characteristics of low F-number diffractive optical elements with continuous relief fabricated by laser direct writing, and continuous-relief diffractive optical elements with a design wavelength of 441.6nm and a F-number of F/4 are fabricated and measured to verify the validity of the diffraction focusing model. The measurements made indicate that the spot size is 1.75mum and the diffraction efficiency is 70.7% at the design wavelength, which coincide well with the theoretical results: a spot size of 1.66mum and a diffraction efficiency of 71.2%.

  3. Electro-optic sampling for time resolving relativistic ultrafast electron diffraction

    International Nuclear Information System (INIS)

    Scoby, C. M.; Musumeci, P.; Moody, J.; Gutierrez, M.; Tran, T.

    2009-01-01

    The Pegasus laboratory at UCLA features a state-of-the-art electron photoinjector capable of producing ultrashort (<100 fs) high-brightness electron bunches at energies of 3.75 MeV. These beams recently have been used to produce static diffraction patterns from scattering off thin metal foils, and it is foreseen to take advantage of the ultrashort nature of these bunches in future pump-probe time-resolved diffraction studies. In this paper, single shot 2-d electro-optic sampling is presented as a potential technique for time of arrival stamping of electron bunches used for diffraction. Effects of relatively low bunch charge (a few 10's of pC) and modestly relativistic beams are discussed and background compensation techniques to obtain high signal-to-noise ratio are explored. From these preliminary tests, electro-optic sampling is suitable to be a reliable nondestructive time stamping method for relativistic ultrafast electron diffraction at the Pegasus lab.

  4. Wave front engineering by means of diffractive optical elements for applications in microscopy

    Science.gov (United States)

    Cojoc, Dan; Ferrari, Enrico; Garbin, Valeria; Cabrini, Stefano; Carpentiero, Alessandro; Prasciolu, Mauro; Businaro, Luca; Kaulich, Burchard; Di Fabrizio, Enzo

    2006-05-01

    We present a unified view regarding the use of diffractive optical elements (DOEs) for microscopy applications a wide range of electromagnetic spectrum. The unified treatment is realized through the design and fabrication of DOE through which wave front beam shaping is obtained. In particular we show applications ranging from micromanipulation using optical tweezers to X-ray differential interference contrast (DIC) microscopy. We report some details on the design and physical implementation of diffractive elements that beside focusing perform also other optical functions: beam splitting, beam intensity and phase redistribution or mode conversion. Laser beam splitting is used for multiple trapping and independent manipulation of spherical micro beads and for direct trapping and manipulation of biological cells with non-spherical shapes. Another application is the Gauss to Laguerre-Gaussian mode conversion, which allows to trap and transfer orbital angular momentum of light to micro particles with high refractive index and to trap and manipulate low index particles. These experiments are performed in an inverted optical microscope coupled with an infrared laser beam and a spatial light modulator for DOEs implementation. High resolution optics, fabricated by means of e-beam lithography, are demonstrated to control the intensity and the phase of the sheared beams in X-ray DIC microscopy. DIC experiments with phase objects reveal a dramatic increase in image contrast compared to bright-field X-ray microscopy.

  5. Photon Sieve Bandwidth Broadening by Reduction of Chromatic Aberration Effects Using Second-Stage Diffractive Optics

    Science.gov (United States)

    2015-03-26

    to copyright protection in the United States. AFIT-ENP-MS-15-M-086 PHOTON SIEVE BANDWIDTH BROADENING BY REDUCTION OF CHROMATIC ABERRATION...RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENP-MS-15-M-086 PHOTON SIEVE BANDWIDTH BROADENING BY REDUCTION OF CHROMATIC ABERRATION EFFECTS USING...A photon sieve is a lightweight diffractive optic which can be useful for space- based imaging applications. It is limited by chromatic

  6. Nano-fabrication of diffractive optics for soft X-ray and atom beam focusing

    International Nuclear Information System (INIS)

    Rehbein, S.

    2002-01-01

    Nano-structuring processes are described for manufacturing diffractive optics for the condenser-monochromator set-up of the transmission X-ray microscope (TXM) and for the scanning transmission X-ray microscope (STXM) at the BESSY II electron storage ring in Berlin. Furthermore, a process for manufacturing free-standing nickel zone plates for helium atom beam focusing experiments is presented. (author)

  7. Gold nanoparticle-polydimethylsiloxane films reflect light internally by optical diffraction and Mie scattering

    International Nuclear Information System (INIS)

    Dunklin, Jeremy R; Keith Roper, D; Forcherio, Gregory T

    2015-01-01

    Optical properties of polymer films embedded with plasmonic nanoparticles (NPs) are important in many implementations. In this work, optical extinction by polydimethylsiloxane (PDMS) films containing gold (Au) NPs was enhanced at resonance compared to AuNPs in suspensions, Beer–Lambert law, or Mie theory by internal reflection due to optical diffraction in 16 nm AuNP–PDMS films and Mie scattering in 76 nm AuNP–PDMS films. Resonant extinction per AuNP for 16 nm AuNPs with negligible resonant Mie scattering was enhanced up to 1.5-fold at interparticle separation (i.e., Wigner–Seitz radii) comparable to incident wavelength. It was attributable to diffraction through apertures formed by overlapping electric fields of adjacent, resonantly excited AuNPs at Wigner–Seitz radii equal to or less than incident wavelengths. Resonant extinction per AuNP for strongly Mie scattering 76 nm AuNPs was enhanced up to 1.3-fold at Wigner–Seitz radii four or more times greater than incident wavelength. Enhanced light trapping from diffraction and/or scattering is relevant to optoelectronic, biomedical, and catalytic activity of substrates embedded with NPs. (paper)

  8. Diffractive optical devices produced by light-assisted trapping of nanoparticles.

    Science.gov (United States)

    Muñoz-Martínez, J F; Jubera, M; Matarrubia, J; García-Cabañes, A; Agulló-López, F; Carrascosa, M

    2016-01-15

    One- and two-dimensional diffractive optical devices have been fabricated by light-assisted trapping and patterning of nanoparticles. The method is based on the dielectrophoretic forces appearing in the vicinity of a photovoltaic crystal, such as Fe:LiNbO3, during or after illumination. By illumination with the appropriate light distribution, the nanoparticles are organized along patterns designed at will. One- and two-dimensional diffractive components have been achieved on X- and Z-cut Fe:LiNbO3 crystals, with their polar axes parallel and perpendicular to the crystal surface, respectively. Diffraction gratings with periods down to around a few micrometers have been produced using metal (Al, Ag) nanoparticles with radii in the range of 70-100 nm. Moreover, several 2D devices, such as Fresnel zone plates, have been also produced showing the potential of the method. The diffractive particle patterns remain stable when light is removed. A method to transfer the diffractive patterns to other nonphotovoltaic substrates, such as silica glass, has been also reported.

  9. A new XUV optical end-station to characterize compact and flexible photonic devices using synchrotron radiation

    Science.gov (United States)

    Marcelli, A.; Mazuritskiy, M. I.; Dabagov, S. B.; Hampai, D.; Lerer, A. M.; Izotova, E. A.; D'Elia, A.; Turchini, S.; Zema, N.; Zuccaro, F.; de Simone, M.; Javad Rezvani, S.; Coreno, M.

    2018-03-01

    In this contribution we present the new experimental end-station to characterize XUV diffractive optics, such as Micro Channel Plates (MCPs) and other polycapillary optics, presently under commission at the Elettra synchrotron radiation laboratory (Trieste, Italy). To show the opportunities offered by these new optical devices for 3rd and 4th generation radiation sources, in this work we present also some patterns collected at different energies of the primary XUV radiation transmitted by MCP optical devices working in the normal incidence geometry.

  10. Therapeutic radiation apparatus having an optical pointer

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification relates to a therapeutic irradiating apparatus including a radiation source arranged to provide a beam of penetrating radiation and an optical alignment indicator comprising at least two light sources each provided with means to provide a planar divergent beam of light located so that at least two light beams intersect along a line substantially coincident with the central axis of the path of the radiation beam. The claim relates to cylindrical lenses providing the means of providing the divergent beams, and to lasers as the light sources. Claims are also made for the apparatus providing means of supporting and aligning the patient, and for disposing the light sources so that the exit point of the radiation beam is illuminated. (U.K.)

  11. Challenges and opportunities in synchrotron radiation optics

    Science.gov (United States)

    Rehn, V.

    Design necessities germaine to advances in optics for experimentation with synchrotron radiation are explored. Objectives for development include improved beam-line performance using new mirror materials or coatings, filtering and order-sorting enhancement, and lower surface scattering. A summary is presented of optical systems currently in use, together with requirements imposed by storage rings and experimental design. Advances are recommended in intensity, collimation, focus, and spectral purity of synchrotron beam lines. Any new storage ring mirror is noted to be required to dissipate several hundred watts, something which polished Cu is mentioned as being capable of handling, while standard SiO2 mirrors cannot.

  12. Radiation resistant characteristics of optical fibers

    International Nuclear Information System (INIS)

    Nakasuji, Masaaki; Tanaka, Gotaro; Watanabe, Minoru; Kyodo, Tomohisa; Mukunashi, Hiroaki

    1983-01-01

    It is required to develop the optical fibers with good radiation resistivity because the fibers cause the increase of transmission loss due to glass colouring when they are used under the presence of radiation such as γ-ray. Generally, it is known that SI (step index) fibers are more resistive to radiation than GI (graded index) fibers. However, since a wide band can not be obtained with SI fibers, the development of radiation resistive GI optical fibers is desirable. In this report, the production for trial of the GI fibers of fluorine-doped silica core, the examination of radiation effect on their optical transmission loss by exposing them to γ-ray, thermal and fast neutron beams and also of mechanical strength are described. The GI fibers of fluorine-doped silica core show better radiation resistivity than Ge-doped ones. The B- and F-doped GI fibers show small increase of loss due to γ-ray, but large increase of loss due to thermal neutron beam. This is supposed to be caused by the far greater neutron absorption cross-section of boron than that of other elements. Significant increase of loss was not recognized when 14 MeV fast neutrons (8.6 x 10 4 n/cm 2 .s) were applied by 1.8 x 10 9 n/cm 2 . It was found that ETFE-covered fiber cores generated fluorine-containing gas due to γ irradiation, and the strength was remarkably lowered, but the lowering of strength can be prevented by adding titanium-white to the covering material. (Wakatsuki, Y.)

  13. Nanofocusing optics for synchrotron radiation made from polycrystalline diamond.

    Science.gov (United States)

    Fox, O J L; Alianelli, L; Malik, A M; Pape, I; May, P W; Sawhney, K J S

    2014-04-07

    Diamond possesses many extreme properties that make it an ideal material for fabricating nanofocusing x-ray optics. Refractive lenses made from diamond are able to focus x-ray radiation with high efficiency but without compromising the brilliance of the beam. Electron-beam lithography and deep reactive-ion etching of silicon substrates have been used in a transfer-molding technique to fabricate diamond optics with vertical and smooth sidewalls. Latest generation compound refractive lenses have seen an improvement in the quality and uniformity of the optical structures, resulting in an increase in their focusing ability. Synchrotron beamline tests of two recent lens arrays, corresponding to two different diamond morphologies, are described. Focal line-widths down to 210 nm, using a nanocrystalline diamond lens array and a beam energy of E = 11 keV, and 230 nm, using a microcrystalline diamond lens at E = 15 keV, have been measured using the Diamond Light Source Ltd. B16 beamline. This focusing prowess is combined with relatively high transmission through the lenses compared with silicon refractive designs and other diffractive optics.

  14. Reducing aberration effect of Fourier transform lens by modifying Fourier spectrum of diffractive optical element in beam shaping optical system.

    Science.gov (United States)

    Zhang, Fang; Zhu, Jing; Song, Qiang; Yue, Weirui; Liu, Jingdan; Wang, Jian; Situ, Guohai; Huang, Huijie

    2015-10-20

    In general, Fourier transform lenses are considered as ideal in the design algorithms of diffractive optical elements (DOEs). However, the inherent aberrations of a real Fourier transform lens disturb the far field pattern. The difference between the generated pattern and the expected design will impact the system performance. Therefore, a method for modifying the Fourier spectrum of DOEs without introducing other optical elements to reduce the aberration effect of the Fourier transform lens is proposed. By applying this method, beam shaping performance is improved markedly for the optical system with a real Fourier transform lens. The experiments carried out with a commercial Fourier transform lens give evidence for this method. The method is capable of reducing the system complexity as well as improving its performance.

  15. Achieving a high mode count in the exact electromagnetic simulation of diffractive optical elements.

    Science.gov (United States)

    Junker, André; Brenner, Karl-Heinz

    2018-03-01

    The application of rigorous optical simulation algorithms, both in the modal as well as in the time domain, is known to be limited to the nano-optical scale due to severe computing time and memory constraints. This is true even for today's high-performance computers. To address this problem, we develop the fast rigorous iterative method (FRIM), an algorithm based on an iterative approach, which, under certain conditions, allows solving also large-size problems approximation free. We achieve this in the case of a modal representation by avoiding the computationally complex eigenmode decomposition. Thereby, the numerical cost is reduced from O(N 3 ) to O(N log N), enabling a simulation of structures like certain diffractive optical elements with a significantly higher mode count than presently possible. Apart from speed, another major advantage of the iterative FRIM over standard modal methods is the possibility to trade runtime against accuracy.

  16. 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

    2015-11-02

    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.

  17. A case of presumed radiation optic neuropathy

    International Nuclear Information System (INIS)

    Atsumi, Osamu; Sakuraba, Tomoki; Kimura, Satoru; Narita, Kiyoharu; Maeda, Syuji

    1991-01-01

    A case of a 37-year-old woman with radiation optic neuropathy was reported. She had undergone subtotal removal of the right orbital tumor (adenoid cystic carcinoma) by frontal craniotomy, followed by radiation therapy (64 Gy). She had been quite well until she noticed a gradual loss of vision in her right eye 18 months later. Her visual acuity was 0.2 in the right eye and 1.5 in the left eye with right relative afferent pupillary defect and dense central scotoma. Funduscopy revealed optic disc swelling with surrounding retinal edema and small hemorrhage in the right eye. Fluorescein angiography revealed a hypoperfusion area and obstruction of the small retinal vessels in the posterior pole, but this was not large enough to explain the dense central scotoma. Although prednisolone therapy gave temporary improvement, the visual function gradually deteriorated. (author)

  18. A case of presumed radiation optic neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Atsumi, Osamu; Sakuraba, Tomoki; Kimura, Satoru; Narita, Kiyoharu; Maeda, Syuji (Hirosaki Univ., Aomori (Japan). School of Medicine)

    1991-05-01

    A case of a 37-year-old woman with radiation optic neuropathy was reported. She had undergone subtotal removal of the right orbital tumor (adenoid cystic carcinoma) by frontal craniotomy, followed by radiation therapy (64 Gy). She had been quite well until she noticed a gradual loss of vision in her right eye 18 months later. Her visual acuity was 0.2 in the right eye and 1.5 in the left eye with right relative afferent pupillary defect and dense central scotoma. Funduscopy revealed optic disc swelling with surrounding retinal edema and small hemorrhage in the right eye. Fluorescein angiography revealed a hypoperfusion area and obstruction of the small retinal vessels in the posterior pole, but this was not large enough to explain the dense central scotoma. Although prednisolone therapy gave temporary improvement, the visual function gradually deteriorated. (author).

  19. Resonant acoustic radiation force optical coherence elastography

    OpenAIRE

    Qi, Wenjuan; Li, Rui; Ma, Teng; Li, Jiawen; Kirk Shung, K.; Zhou, Qifa; Chen, Zhongping

    2013-01-01

    We report on a resonant acoustic radiation force optical coherence elastography (ARF-OCE) technique that uses mechanical resonant frequency to characterize and identify tissues of different types. The linear dependency of the resonant frequency on the square root of Young's modulus was validated on silicone phantoms. Both the frequency response spectrum and the 3D imaging results from the agar phantoms with hard inclusions confirmed the feasibility of deploying the resonant frequency as a mec...

  20. A novel automotive headlight system based on digital micro-mirror devices and diffractive optical elements

    Science.gov (United States)

    Su, Ping; Song, Yuming; Ma, Jianshe

    2018-01-01

    The DMD (Digital Micro-mirror Device) has the advantages of high refresh rate and high diffraction efficiency, and these make it become an ideal loader of multiple modes illumination. DOEs (Diffractive Optical Element) have the advantages of high degree of freedom, light weight, easy to copy, low cost etc., and can be used to reduce the weight, complexity, cost of optical system. A novel automotive headlamp system using DMD as the light distribution element and a DOE as the light field modulation device is proposed in this paper. The pure phase DOE is obtained by the GS algorithm using Rayleigh-Sommerfeld diffraction integral model. Based on the standard automotive headlamp light intensity distribution in the target plane, the amplitude distribution of DMD is obtained by numerical simulation, and the grayscale diagram loaded on the DMD can be obtained accordingly. Finally, according to simulation result, the light intensity distribution in the target plane is proportional to the national standard, hence verifies the validity of the novel system. The novel illumination system proposed in this paper provides a reliable hardware platform for the intelligent headlamps.

  1. Optical Tracking Technology in Stereotactic Radiation Therapy

    International Nuclear Information System (INIS)

    Wagner, Thomas H.; Meeks, Sanford L.; Bova, Frank J.; Friedman, William A.; Willoughby, Twyla R.; Kupelian, Patrick A.; Tome, Wolfgang

    2007-01-01

    The last decade has seen the introduction of advanced technologies that have enabled much more precise application of therapeutic radiation. These relatively new technologies include multileaf collimators, 3-dimensional conformal radiotherapy planning, and intensity modulated radiotherapy in radiotherapy. Therapeutic dose distributions have become more conformal to volumes of disease, sometimes utilizing sharp dose gradients to deliver high doses to target volumes while sparing nearby radiosensitive structures. Thus, accurate patient positioning has become even more important, so that the treatment delivered to the patient matches the virtual treatment plan in the computer treatment planning system. Optical and image-guided radiation therapy systems offer the potential to improve the precision of patient treatment by providing a more robust fiducial system than is typically used in conventional radiotherapy. The ability to accurately position internal targets relative to the linac isocenter and to provide real-time patient tracking theoretically enables significant reductions in the amount of normal tissue irradiated. This report reviews the concepts, technology, and clinical applications of optical tracking systems currently in use for stereotactic radiation therapy. Applications of radiotherapy optical tracking technology to respiratory gating and the monitoring of implanted fiducial markers are also discussed

  2. Calculated efficiencies of three-material low stress coatings for diffractive x-ray transmission optics

    International Nuclear Information System (INIS)

    Kubec, Adam; Braun, Stefan; Gawlitza, Peter; Menzel, Maik; Leson, Andreas

    2016-01-01

    Diffractive X-ray optical elements made by thin film coating techniques such as multilayer Laue lenses (MLL) and multilayer zone plates (MZP) are promising approaches to achieve resolutions in hard X-ray microscopy applications of less than 10 nm. The challenge is to make a lens with a large numerical aperture on the one hand and a decent working distance on the other hand. One of the limiting factors with the coated structures is the internal stress in the films, which can lead to significant bending of the substrate and various types of unwanted diffraction effects. Several approaches have been discussed to overcome this challenge. One of these is a three-material combination such as Mo/MoSi_2/Si, where four single layers per period are deposited. Mo and Si represent the absorber and spacer in this case while MoSi_2 forms a diffusion barrier; in addition the thicknesses of absorber and spacer are chosen to minimize residual stress of the overall coating. Here the diffraction efficiency as well as the profile of the beam in the focal plane are discussed in order to find a tradeoff between lowest residual stress and best diffraction properties.

  3. Slow scan sit detector for x-ray diffraction studies using synchrotron radiation

    International Nuclear Information System (INIS)

    Milch, J.R.

    1978-01-01

    A TV-type x-ray detector using a SIT vidicon has been used for biological diffraction studies at the EMBL outstation at DESY, Hamburg, Germany. The detector converts the two-dimensional diffraction pattern to a charge pattern on the vidicon target, which is read out in the slow-scan mode. This detector has high DOE, no count-rate limit, and is simple and inexpensive to construct. Radiation from the storage ring DORIS was used to study the structure of live muscle at various phases of contraction. Typically the count-rate on the detector was 10 6 x-rays/sec and a total exposure of a few seconds was needed to record the weak diffraction from muscle. This compares with usual exposure times of several hours using a rotating anode generator and film

  4. Optical fibers and their applications for radiation measurements

    International Nuclear Information System (INIS)

    Kakuta, Tsunemi

    1998-01-01

    As a new method of radiation measurements, several optical methods using optical fiber sensors have been developed. One is the application of 'radio-luminescence' from the optical fiber itself such as plastic scintillating fibers. Other researches are made to develop the 'combined-sensors' by combination of optical fibers and scintillating materials. Using the time domain method of optical fiber sensors, the profile of radiation distribution along the optical fiber can be easily determined. A multi-parameter sensing system for measurement of radiation, temperature, stress, etc, are also expected using these optical fiber sensors. (author)

  5. X-ray diffraction and imaging with a coherent beam: application to X-ray optical elements and to crystals exhibiting phase inhomogeneities

    International Nuclear Information System (INIS)

    Masiello, F.

    2011-05-01

    The exceptional properties of synchrotron light sources have been exploited in very different disciplines, from archaeology to chemistry, from material science to biology, from medicine to physics. Among these properties it is important to mention the high brilliance, continuum spectrum, high degree of polarization, time structure, small source size and divergence of the beam, the last resulting in a high transversal coherence of the produced radiation. This high transversal coherence of the synchrotron sources has permitted the development of new techniques, e.g. phase contrast imaging, X-ray photon correlation spectroscopy and coherent X-ray diffraction imaging (CXDI). This thesis work will consist essentially of three parts. In the first part it will be presented the work done as a member of the X-ray Optics Group of ESRF in the characterization of high quality diamond crystals foreseen as X-ray optical elements. The characterization has been done using different complementary X-ray techniques, such as high resolution diffraction, topography, grazing incidence diffraction, reflectivity and measurements of the coherence preservation using the Talbot effect. In the second part, I will show the result obtained in the study of the temperature behaviours of the domain in periodically poled ferroelectrics crystals. This type of measurements, based on Bragg-Fresnel diffraction, are possible only thanks to the high degree of coherence of the beam. In the third part, I will present the results obtained in the characterization of diamonds foreseen for applications other than X-ray optical elements. (author)

  6. Genetic local search algorithm for optimization design of diffractive optical elements.

    Science.gov (United States)

    Zhou, G; Chen, Y; Wang, Z; Song, H

    1999-07-10

    We propose a genetic local search algorithm (GLSA) for the optimization design of diffractive optical elements (DOE's). This hybrid algorithm incorporates advantages of both genetic algorithm (GA) and local search techniques. It appears better able to locate the global minimum compared with a canonical GA. Sample cases investigated here include the optimization design of binary-phase Dammann gratings, continuous surface-relief grating array generators, and a uniform top-hat focal plane intensity profile generator. Two GLSA's whose incorporated local search techniques are the hill-climbing method and the simulated annealing algorithm are investigated. Numerical experimental results demonstrate that the proposed algorithm is highly efficient and robust. DOE's that have high diffraction efficiency and excellent uniformity can be achieved by use of the algorithm we propose.

  7. X-ray diffraction on nanoparticles chromium and nickel oxides obtained by gelatin using synchrotron radiation

    International Nuclear Information System (INIS)

    Menezes, Alan Silva de; Medeiros, Angela Maria de Lemos; Miranda, Marcus Aurelio Ribeiro; Almeida, Juliana Marcela Abraao; Remedios, Claudio Marcio Rocha; Silva, Lindomar R.D. da; Gouveia, S.T.; Sasaki, Jose Marcos; Jardim, P.M.

    2003-01-01

    Full text: Cr 2 O 3 nanoparticles has many applications like green pigments, wear resistance, and coating materials for thermal protection. Several methods to produce chromium oxide nanoparticles have already been studied, gas condensation, laser induced pyrolysis, microwave plasma, sol-gel and gamma radiation methods. Many applications for this kind of material can be provide concerning the particle size. For instance, particle size approximately of 200 nm are preferable as pigment due to its opacity and below 50 nm can be used as transparent pigment. In this work we have demonstrated that chromium and nickel oxide nanoparticles can be prepared by gelatin method. X-Ray diffraction (XRD) show that mean particle size for chromium oxide of 15-150 nm and nickel oxide of 90 nm were obtained for several temperature of sintering. The X-Ray powder diffraction pattern were performed using Synchrotron Radiation X-Ray source at XRD1 beamline in National Laboratory of Light Synchrotron (LNLS). (author)

  8. 'Diffraction-free' optical beams in inverse free electron laser accelerators

    International Nuclear Information System (INIS)

    Cai, S.Y.; Bhattacharjee, A.; Marshall, T.C.

    1988-01-01

    'Diffraction-free' optical beams correspond to exact solutions of the wave equation in free space with the remarkable property that they propagate with negligible transverse spreading for distances much larger than the Rayleigh range. The requirement for this to occur is a large aperture. Using a 2D computer code, we find that these optical beams will also propagate with negligible diffraction even when perturbed by the electron beam in an IFEL; indeed they match well the FEL requirement for the accelerator. The numerical simulations are performed for the proposed facility at Brookhaven in which λ s =10 μm, B=1.5 T (linearly tapered l w =1.31-6.28 cm) and the optical beam power is either 8x10 11 W or 2.3x10 10 W. Approximately 70% of the electrons constituting a beam of current 5 mA or 15 A, radius 0.14 mm and initial energy of 50 MeV is accelerated at 50 MeV/m. (orig.)

  9. Diffraction analysis of sidelobe characteristics of optical elements with ripple error

    Science.gov (United States)

    Zhao, Lei; Luo, Yupeng; Bai, Jian; Zhou, Xiangdong; Du, Juan; Liu, Qun; Luo, Yujie

    2018-03-01

    The ripple errors of the lens lead to optical damage in high energy laser system. The analysis of sidelobe on the focal plane, caused by ripple error, provides a reference to evaluate the error and the imaging quality. In this paper, we analyze the diffraction characteristics of sidelobe of optical elements with ripple errors. First, we analyze the characteristics of ripple error and build relationship between ripple error and sidelobe. The sidelobe results from the diffraction of ripple errors. The ripple error tends to be periodic due to fabrication method on the optical surface. The simulated experiments are carried out based on angular spectrum method by characterizing ripple error as rotationally symmetric periodic structures. The influence of two major parameter of ripple including spatial frequency and peak-to-valley value to sidelobe is discussed. The results indicate that spatial frequency and peak-to-valley value both impact sidelobe at the image plane. The peak-tovalley value is the major factor to affect the energy proportion of the sidelobe. The spatial frequency is the major factor to affect the distribution of the sidelobe at the image plane.

  10. Pulse shape and spectrum of coherent diffraction-limited transition radiation from electron beams

    Energy Technology Data Exchange (ETDEWEB)

    van Tilborg, J.; Schroeder, C.B.; Esarey, E.; Leemans, W.P.

    2003-12-20

    The electric field in the temporal and spectral domain of coherent diffraction-limited transition radiation is studied. An electron bunch, with arbitrary longitudinal momentum distribution, propagating at normal incidence to a sharp metal-vacuum boundary with finite transverse dimension is considered. A general expression for the spatiotemporal electric field of the transition radiation is derived, and closed-form solutions for several special cases are given. The influence of parameters such as radial boundary size, electron momentum distribution, and angle of observation on the waveform (e.g., radiation pulse length and amplitude) are discussed. For a Gaussian electron bunch, the coherent radiation waveform is shown to have a single-cycle profile. Application to a novel THz source based on a laser-driven accelerator is discussed.

  11. Optical Fibers in Nuclear Reactor Radiation Environments.

    Science.gov (United States)

    Holcomb, David Eugene

    1992-01-01

    A performance evaluation of fiber optics under radiation conditions similar to those encountered in nuclear power plants is reported. The evaluation was accomplished by the creation of an analytical model for atomic scale radiation damage in silica glass and by the execution of an extensive fiber performance measurement program. The analytic model calculates displacement and electronic damage rates for silica glass subjected to a specified nuclear reactor radiation environment. It accomplishes this by first generating the primary charged particle spectrum produced in silica irradiated in a nuclear reactor. The resultant spectra are then applied to the integral equations describing radiation damage in polyatomic solids. The experimental measurements were selected to span the range of fiber types, radiation environments, temperatures, and light powers expected to be used in nuclear power plants. The basic experimental protocol was to expose the optical fibers to either a nuclear reactor or a ^{60}Co radiation environment while simultaneously monitoring fiber light transmission. Experimental temperatures were either ~23 ^circC or ~100 ^circC and light powers were either -30 dBm or -60 dBm. Measurements were made at each of the three standard communications wavelengths (850 nm, 1300 nm, and 1550 nm). Several conclusions are made based on these performance measurements. First, even near the core of a nuclear reactor the vast majority of the dose to silica glass is due to gamma rays. Even with the much lower doses (factor of roughly 40) neutrons cause much more displacement damage than gamma rays (35 times the oxygen displacement rate and 500 times the silicon displacement rate). Even with neutrons having many times the displacement rate as compared with gamma rays, little if any difference is observed in the transmission losses for gamma only as compared to mixed neutron/gamma transmission losses. Therefore, atomic displacement is not a significant damage mechanism for

  12. Design and fabrication of continuous-profile diffractive micro-optical elements as a beam splitter.

    Science.gov (United States)

    Feng, Di; Yan, Yingbai; Jin, Guofan; Fan, Shoushan

    2004-10-10

    An optimization algorithm that combines a rigorous electromagnetic computation model with an effective iterative method is utilized to design diffractive micro-optical elements that exhibit fast convergence and better design quality. The design example is a two-dimensional 1-to-2 beam splitter that can symmetrically generate two focal lines separated by 80 microm at the observation plane with a small angle separation of +/- 16 degrees. Experimental results are presented for an element with continuous profiles fabricated into a monocrystalline silicon substrate that has a width of 160 microm and a focal length of 140 microm at a free-space wavelength of 10.6 microm.

  13. Ellipsoidal diffraction grating as output coupler for quasi-optical gyrotrons

    International Nuclear Information System (INIS)

    Hogge, J.P.; Cao, H.; Tran, T.M.; Tran, M.Q.; Paris, P.J.; Kasparek, W.

    1991-01-01

    The use of a diffraction grating arranged in the -1 Littrow mount as an output coupler for a quasi-optical Fabry-Perot resonator at microwave frequencies (100 GHz) was suggested in 1990. A planar grating with curvilinear grooves (in order to match the Littrow condition everywhere on the surface for a given Gaussian beam) gives a power coupling efficiency of 85% which is limited by the depolarization but gave approximately the same global efficiency because of distortion. We report low power tests on an improvement of the second scheme, based on curved grooves on an ellipsoidal surface, which gives a global efficiency of 94%. (author) 3 figs., 3 refs

  14. Amplitude-phase characteristics of electromagnetic fields diffracted by a hole in a thin film with realistic optical properties

    Science.gov (United States)

    Dorofeyev, Illarion

    2009-03-01

    Characteristics of a quasi-spherical wave front of an electromagnetic field diffracted by a subwavelength hole in a thin film with real optical properties are studied. Related diffraction problem is solved in general by use of the scalar and vector Green's theorems and related Green's function of a boundary-value problem. Local phase deviations of a diffracted wave front from an ideal spherical front are calculated. Diffracted patterns are calculated for the coherent incident fields in case of holes array in a screen of perfect conductivity.

  15. Application of a universal optic data link for radiation measurements

    International Nuclear Information System (INIS)

    Komatsu, T.; Takada, E.

    2002-01-01

    Optic Data Link (ODL) is a device to convert electric and optic signals to each other, which is used for the field of optical communications. We examined the possibility to apply ODLs to radiation measurements. The effect of ODLs on energy and timing resolution has been investigated. From the results, fundamental applicability of ODLs to radiation measurements has been demonstrated. (author)

  16. Optical Design of COATLI: A Diffraction-Limited Visible Imager with Fast Guiding and Active Optics Correction

    Science.gov (United States)

    Fuentes-Fernández, J.; Cuevas, S.; Watson, A. M.

    2018-04-01

    We present the optical design of COATLI, a two channel visible imager for a comercial 50 cm robotic telescope. COATLI will deliver diffraction-limited images (approximately 0.3 arcsec FWHM) in the riz bands, inside a 4.2 arcmin field, and seeing limited images (approximately 0.6 arcsec FWHM) in the B and g bands, inside a 5 arcmin field, by means of a tip-tilt mirror for fast guiding, and a deformable mirror for active optics, both located on two optically transferred pupil planes. The optical design is based on two collimator-camera systems plus a pupil transfer relay, using achromatic doublets of CaF2 and S-FTM16 and one triplet of N-BK7 and CaF2. We discuss the effciency, tolerancing, thermal behavior and ghosts. COATLI will be installed at the Observatorio Astronómico Nacional in Sierra San Pedro Mártir, Baja California, Mexico, in 2018.

  17. Synchrotron Bragg diffraction imaging characterization of synthetic diamond crystals for optical and electronic power device applications.

    Science.gov (United States)

    Tran Thi, Thu Nhi; Morse, J; Caliste, D; Fernandez, B; Eon, D; Härtwig, J; Barbay, C; Mer-Calfati, C; Tranchant, N; Arnault, J C; Lafford, T A; Baruchel, J

    2017-04-01

    Bragg diffraction imaging enables the quality of synthetic single-crystal diamond substrates and their overgrown, mostly doped, diamond layers to be characterized. This is very important for improving diamond-based devices produced for X-ray optics and power electronics applications. The usual first step for this characterization is white-beam X-ray diffraction topography, which is a simple and fast method to identify the extended defects (dislocations, growth sectors, boundaries, stacking faults, overall curvature etc. ) within the crystal. This allows easy and quick comparison of the crystal quality of diamond plates available from various commercial suppliers. When needed, rocking curve imaging (RCI) is also employed, which is the quantitative counterpart of monochromatic Bragg diffraction imaging. RCI enables the local determination of both the effective misorientation, which results from lattice parameter variation and the local lattice tilt, and the local Bragg position. Maps derived from these parameters are used to measure the magnitude of the distortions associated with polishing damage and the depth of this damage within the volume of the crystal. For overgrown layers, these maps also reveal the distortion induced by the incorporation of impurities such as boron, or the lattice parameter variations associated with the presence of growth-incorporated nitrogen. These techniques are described, and their capabilities for studying the quality of diamond substrates and overgrown layers, and the surface damage caused by mechanical polishing, are illustrated by examples.

  18. Optical radiation emissions from compact fluorescent lamps

    International Nuclear Information System (INIS)

    Khazova, M.; O'Hagan, J.B.

    2008-01-01

    There is a drive to energy efficiency to mitigate climate change. To meet this challenge, the UK Government has proposed phasing out incandescent lamps by the end of 2011 and replacing them with energy efficient fluorescent lighting, including compact fluorescent lamps (CFLs) with integrated ballasts. This paper presents a summary of an assessment conducted by the Health Protection Agency in March 2008 to evaluate the optical radiation emissions of CFLs currently available in the UK consumer market. The study concluded that the UV emissions from a significant percentage of the tested CFLs with single envelopes may result in foreseeable overexposure of the skin when these lamps are used in desk or task lighting applications. The optical output of all tested CFLs, in addition to high-frequency modulation, had a 100-Hz envelope with modulation in excess of 15%. This degree of modulation may be linked to a number of adverse effects. (authors)

  19. Optical substrate materials for synchrotron radiation beamlines

    International Nuclear Information System (INIS)

    Howells, M.R.; Paquin, R.A.

    1997-06-01

    The authors consider the materials choices available for making optical substrates for synchrotron radiation beam lines. They find that currently the optical surfaces can only be polished to the required finish in fused silica and other glasses, silicon, CVD silicon carbide, electroless nickel and 17-4 PH stainless steel. Substrates must therefore be made of one of these materials or of a metal that can be coated with electroless nickel. In the context of material choices for mirrors they explore the issues of dimensional stability, polishing, bending, cooling, and manufacturing strategy. They conclude that metals are best from an engineering and cost standpoint while the ceramics are best from a polishing standpoint. They then give discussions of specific materials as follows: silicon carbide, silicon, electroless nickel, Glidcop trademark, aluminum, precipitation-hardening stainless steel, mild steel, invar and superinvar. Finally they summarize conclusions and propose ideas for further research

  20. Revisiting Bragg's X-ray microscope: scatter based optical transient grating detection of pulsed ionising radiation.

    Science.gov (United States)

    Fullagar, Wilfred K; Paganin, David M; Hall, Chris J

    2011-06-01

    Transient optical gratings for detecting ultrafast signals are routine for temporally resolved photochemical investigations. Many processes can contribute to the formation of such gratings; we indicate use of optically scattering centres that can be formed with highly variable latencies in different materials and devices using ionising radiation. Coherent light scattered by these centres can form the short-wavelength-to-optical-wavelength, incoherent-to-coherent basis of a Bragg X-ray microscope, with inherent scope for optical phasing. Depending on the dynamics of the medium chosen, the way is open to both ultrafast pulsed and integrating measurements. For experiments employing brief pulses, we discuss high-dynamic-range short-wavelength diffraction measurements with real-time optical reconstructions. Applications to optical real-time X-ray phase-retrieval are considered. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. X-ray diffraction characteristics of curved monochromators for sychrotron radiation

    International Nuclear Information System (INIS)

    Boeuf, A.; Rustichelli, F.; Mazkedian, S.; Puliti, P.; Melone, S.

    1978-01-01

    A theoretical study is presented concerning the diffraction characteristics of curved monochromators for X-ray synchrotron radiation used at the laboratories of Hamburg, Orsay and Stanford. The investigation was performed by extending to the X-ray case a simple model recently developed and fruitfully employed to describe the neutron diffraction properties of curved monochromators. Several diffraction patterns were obtained corresponding to different monochromator materials (Ge, Si) used by the different laboratories, for different reflecting planes (111), (220), asymmetry angles, X-ray wave-lengths (Mo Kα, Cu Kα, Cr Kα) and curvature radii. The results are discussed in physical terms and their implications on the design of curved monochromators for synchrotron radiation are presented. In particular, the study shows that all the monochromators used in the different laboratories should behave practically as perfect crystals and therefore should have a very low integrated reflectivity corresponding to an optimized wavelength passband Δlambda/lambda approximately 10 -4 . The gain that can be obtained by increasing the curvature, by introducing a gradient in the lattice spacing or by any other kind of imperfection is quite limited and much lower than the desirable value. The adopted model can help in obtaining a possible moderate gain in intensity by also taking into consideration other parameters, such as crystal material, reflecting plane, asymmetry of the reflection and X-ray wavelength. (Auth.)

  2. The European Synchrotron Radiation Facility - an overview of planned diffraction capability

    International Nuclear Information System (INIS)

    Kvick, A.

    1991-01-01

    The European Synchrotron Radiation Facility (ESRF) is a third generation synchrotron radiation facility presently being built as a joint venture between 12 European countries in Grenoble, France. The ESRF will be a low emittance 6 GeV storage ring aimed at producing high-brilliance synchrotron radiation from 29 insertion devices and from 27 bending magnet ports. The general user program will start in the middle of 1994 with seven ESRF beam-lines. By 1999, 30 facility beam-lines as well as beam-lines built and financed by Collaborating Research Groups are scheduled to be in operation. The guidelines for the first beam-lines to be constructed as well as a survey of the diffraction oriented beam-lines built by the ESRF are given in the article. (author)

  3. Water-wave diffraction and radiation by multiple three-dimensional bodies over a mild-slope bottom

    DEFF Research Database (Denmark)

    Ruiz, Pau Mercadé; Ferri, Francesco; Kofoed, Jens Peter

    2017-01-01

    Highlights •A tool to model wave diffraction and radiation in mild-slope bottoms is proposed. •The tool combines a mild-slope equation model with diffraction transfer matrices. •The tool predictions are verified against analytical solutions for two test problems....

  4. Nanointaglio fabrication of optical lipid multilayer diffraction gratings with applications in biosensing

    Science.gov (United States)

    Lowry, Troy Warren

    The dynamic self-organization of lipids in biological systems is a highly regulated process that enables the compartmentalization of living systems at microscopic and nanoscopic levels. Exploiting the self-organization and innate biofunctionality of lyotropic liquid crystalline phospholipids, a novel nanofabrication process called "nanointaglio" was invented in order to rapidly and scalably integrate lipid nanopatterns onto the surface. The work presented here focuses on using nanointaglio fabricated lipid diffraction micro- and nanopatterns for the development of new sensing and bioactivity studies. The lipids are patterned as diffraction gratings for sensor functionality. The lipid multilayer gratings operate as nanomechanical sensor elements that are capable of transducing molecular binding to fluid lipid multilayers into optical signals in a label free manner due to shape changes in the lipid nanostructures. To demonstrate the label free detection capabilities, lipid nanopatterns are shown to be suitable for the integration of chemically different lipid multilayer gratings into a sensor array capable of distinguishing vapors by means of an optical nose. Sensor arrays composed of six different lipid formulations are integrated onto a surface and their optical response to three different vapors (water, ethanol and acetone) in air as well as pH under water is monitored as a function of time. Principal component analysis of the array response results in distinct clustering, indicating the suitability of the arrays for distinguishing these analytes. Importantly, the nanointaglio process used is capable of producing lipid gratings out of different materials with sufficiently uniform heights for the fabrication of an optical nose. A second main application is demonstrated for the study of membrane binding proteins. Although in vitro methods for assaying the catalytic activity of individual enzymes are well established, quantitative methods for assaying the kinetics of

  5. Chirality and angular momentum in optical radiation

    Science.gov (United States)

    Coles, Matt M.; Andrews, David L.

    2012-06-01

    This paper develops, in precise quantum electrodynamic terms, photonic attributes of the “optical chirality density,” one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends insights into some recent interpretations of chiroptical experiments, in which this measure, and an associated chirality flux, have been treated as representing physically distinctive “superchiral” phenomena. In the fully quantized formalism the chirality density is promoted to operator status, whose exploration with reference to an arbitrary polarization basis reveals relationships to optical angular momentum and helicity operators. Analyzing multimode beams with complex wave-front structures, notably Laguerre-Gaussian modes, affords a deeper understanding of the interplay between optical chirality and optical angular momentum. By developing theory with due cognizance of the photonic character of light, it emerges that only the spin-angular momentum of light is engaged in such observations. Furthermore, it is shown that these prominent measures of the helicity of chiral electromagnetic radiation have a common basis in differences between the populations of optical modes associated with angular momenta of opposite sign. Using a calculation of the rate of circular dichroism as an example, with coherent states to model the electromagnetic field, it is discovered that two terms contribute to the differential effect. The primary contribution relates to the difference in left- and right-handed photon populations; the only other contribution, which displays a sinusoidal distance dependence corresponding to the claim of nodal enhancements, is connected with the quantum photon number-phase uncertainty relation. From the full analysis, it appears that the term “superchiral” can be considered redundant.

  6. Correct interpretation of diffraction properties of quartz crystals for X-ray optics applications

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xian-Rong; Gog, Thomas; Kim, Jungho; Kasman, Elina; Said, Ayman H.; Casa, Diego M.; Wieczorek, Michael; Hönnicke, Marcelo G.; Assoufid, Lahsen

    2018-02-01

    Quartz has hundreds of strong Bragg reflections that may offer a great number of choices for making fixed-angle X-ray analyzers and polarizers at virtually any hard X-ray energies with selectable resolution. However, quartz crystals, unlike silicon and germanium, are chiral and may thus appear in two different forms of handedness that are mirror images. Furthermore, because of the threefold rotational symmetry along thecaxis, the {h1h2h3L} and {h2h1h3L} Bragg reflections may have quite different Darwin bandwidth, reflectivity and angular acceptance, although they have the same Bragg angle. The design of X-ray optics from quartz crystals therefore requires unambiguous determination of the orientation, handedness and polarity of the crystals. The Laue method and single-axis diffraction technique can provide such information, but the variety of conventions used in the literature to describe quartz structures has caused widespread confusion. The current studies give detailed guidelines for design and fabrication of quartz X-ray optics, with special emphasis on the correct interpretation of Laue patterns in terms of the crystallography and diffraction properties of quartz. Meanwhile, the quartz crystals examined were confirmed by X-ray topography to have acceptably low densities of dislocations and other defects, which is the foundation for developing high-resolution quartz-based X-ray optics.

  7. An optical super-microscope for far-field, real-time imaging beyond the diffraction limit.

    Science.gov (United States)

    Wong, Alex M H; Eleftheriades, George V

    2013-01-01

    Optical microscopy suffers from a fundamental resolution limitation arising from the diffractive nature of light. While current solutions to sub-diffraction optical microscopy involve combinations of near-field, non-linear and fine scanning operations, we hereby propose and demonstrate the optical super-microscope (OSM) - a superoscillation-based linear imaging system with far-field working and observation distances - which can image an object in real-time and with sub-diffraction resolution. With our proof-of-principle prototype we report a point spread function with a spot size clearly reduced from the diffraction limit, and demonstrate corresponding improvements in two-point resolution experiments. Harnessing a new understanding of superoscillations, based on antenna array theory, our OSM achieves far-field, sub-diffraction optical imaging of an object without the need for fine scanning, data post-processing or object pre-treatment. Hence the OSM can be used in a wide variety of imaging applications beyond the diffraction limit, including real-time imaging of moving objects.

  8. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

    Sand, J.; Hannuksela, V.; Toivonen, J.; Ihantola, S.; Peraejaervi, K.; Toivonen, H.

    2010-01-01

    Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

  9. X-ray radiation damage of organic semiconductor thin films during grazing incidence diffraction experiments

    Energy Technology Data Exchange (ETDEWEB)

    Neuhold, A., E-mail: alfred.neuhold@tugraz.at [Institute of Solid State Physics, Graz University of Technology, Graz (Austria); Novak, J.; Flesch, H.-G.; Moser, A.; Djuric, T. [Institute of Solid State Physics, Graz University of Technology, Graz (Austria); Grodd, L.; Grigorian, S.; Pietsch, U. [Institute of Physics, University Siegen (Germany); Resel, R. [Institute of Solid State Physics, Graz University of Technology, Graz (Austria)

    2012-08-01

    Since modern synchrotrons with highly intense X-ray beams are in use to investigate organic materials, the stability of soft matter materials during beam exposure is a crucial issue. Grazing incidence X-ray diffraction and specular X-ray reflectivity measurements were performed on thin films of organic semiconducting materials, like poly(3-hexylthiophene) (P3HT), sexithiophene and pentacene. These films were irradiated with an average flux density between 10{sup 15} and 10{sup 16} photons/(s mm{sup 2}) and evidenced a different stability in synchrotron X-ray radiation. The semi-crystalline P3HT showed a clear intensity decrease of the 1 0 0 Bragg peak and 0 2 0 Bragg peak compared to the rather stable diffraction features of the molecular crystals sexithiophene and pentacene. The difference in synchrotron X-ray radiation stability is explained by the interaction of the X-ray beam with the individual chemical components in the molecules as well as by the different crystallinities of the materials. Furthermore, the semi-crystalline P3HT film exhibited an increase of film thickness after irradiation and the surface roughness slightly decreased. To summarize, this study shows a strong influence of synchrotron X-ray radiation to specific organic thin films like e.g. P3HT, while others like pentacene and sexithiophene are observed as quite stable.

  10. Multi-wavelength speckle reduction for laser pico-projectors using diffractive optics

    Science.gov (United States)

    Thomas, Weston H.

    Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser's stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a

  11. Radiation distribution sensing with normal optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Kawarabayashi, Jun; Mizuno, Ryoji; Naka, Ryotaro; Uritani, Akira; Watanabe, Ken-ichi; Iguchi, Tetsuo [Nagoya Univ., Dept. of Nuclear Engineering, Nagoya, Aichi (Japan); Tsujimura, Norio [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan)

    2002-12-01

    The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length (10m-100m) and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The characteristics of this monitor to beta particles, gamma rays and fast neutrons were obtained. The spatial resolutions for beta particles ({sup 90}Sr{sup -90}Y), gamma rays ({sup 137}Cs) and D-T neutrons were 30 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the gamma rays and D-T neutrons were 0.11%, 1.6x10{sup -5}% and 5.4x10{sup -4}%, respectively. The effective attenuation length of the detection efficiency was 18m. New principle of the position sensing based on spectroscopic analysis was also proposed. A preliminary test showed that the spectrum observed at the end of the fiber depended on the position of the irradiated point. This fact shows that the radiation distributions were calculated from the spectrum by mathematical deconvolution technique. (author)

  12. Radiation distribution sensing with normal optical fiber

    International Nuclear Information System (INIS)

    Kawarabayashi, Jun; Mizuno, Ryoji; Naka, Ryotaro; Uritani, Akira; Watanabe, Ken-ichi; Iguchi, Tetsuo; Tsujimura, Norio

    2002-01-01

    The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length (10m-100m) and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The characteristics of this monitor to beta particles, gamma rays and fast neutrons were obtained. The spatial resolutions for beta particles ( 90 Sr -90 Y), gamma rays ( 137 Cs) and D-T neutrons were 30 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the gamma rays and D-T neutrons were 0.11%, 1.6x10 -5 % and 5.4x10 -4 %, respectively. The effective attenuation length of the detection efficiency was 18m. New principle of the position sensing based on spectroscopic analysis was also proposed. A preliminary test showed that the spectrum observed at the end of the fiber depended on the position of the irradiated point. This fact shows that the radiation distributions were calculated from the spectrum by mathematical deconvolution technique. (author)

  13. A spectrometer for X-ray energy-dispersive diffraction using synchrotron radiation

    International Nuclear Information System (INIS)

    Buras, B.; Gerward, L.; Staun Olsen, J.; Steenstrup, S.

    1981-10-01

    The paper describes a white-beam X-ray energy dispersive diffractometer using the synchroton radiation from the DORIS ESR. The following features of the instrument are discussed: Horizontal or vertical scattering plane, collimators, sample environment, remote control of gonimeter, data acquisition, energy-sensitive detectors using small-area and large-area detector crystals, modes of operation, powder and single crystal diffraction. An example is given from a high-pressure study of YbH 2 using a diamond anvil cell. (orig./HP)

  14. Transition from two-dimensional photonic crystals to dielectric metasurfaces in the optical diffraction with a fine structure

    Science.gov (United States)

    Rybin, Mikhail V.; Samusev, Kirill B.; Lukashenko, Stanislav Yu.; Kivshar, Yuri S.; Limonov, Mikhail F.

    2016-01-01

    We study experimentally a fine structure of the optical Laue diffraction from two-dimensional periodic photonic lattices. The periodic photonic lattices with the C4v square symmetry, orthogonal C2v symmetry, and hexagonal C6v symmetry are composed of submicron dielectric elements fabricated by the direct laser writing technique. We observe surprisingly strong optical diffraction from a finite number of elements that provides an excellent tool to determine not only the symmetry but also exact number of particles in the finite-length structure and the sample shape. Using different samples with orthogonal C2v symmetry and varying the lattice spacing, we observe experimentally a transition between the regime of multi-order diffraction, being typical for photonic crystals to the regime where only the zero-order diffraction can be observed, being is a clear fingerprint of dielectric metasurfaces characterized by effective parameters. PMID:27491952

  15. Laser frequency stabilisation by the Pound - Drever - Hall method using an acousto-optic phase modulator operating in the pure Raman - Nath diffraction regime

    International Nuclear Information System (INIS)

    Baryshev, Vyacheslav N

    2012-01-01

    Frequency stabilisation of diode laser radiation has been implemented by the Pound - Drever - Hall method using a new acousto-optic phase modulator, operating in the pure Raman - Nath diffraction regime. It is experimentally shown that, as in the case of saturated-absorption spectroscopy in atomic vapour, the spatial divergence of the frequency-modulated output spectrum of this modulator does not interfere with obtaining error signals by means of heterodyne frequency-modulation spectroscopy with a frequency discriminator based on a high-Q Fabry - Perot cavity with finesse of several tens of thousands.

  16. A uniform geometrical optics and an extended uniform geometrical theory of diffraction for evaluating high frequency EM fields near smooth caustics and composite shadow boundaries

    Science.gov (United States)

    Constantinides, E. D.; Marhefka, R. J.

    1994-01-01

    A uniform geometrical optics (UGO) and an extended uniform geometrical theory of diffraction (EUTD) are developed for evaluating high frequency electromagnetic (EM) fields within transition regions associated with a two and three dimensional smooth caustic of reflected rays and a composite shadow boundary formed by the caustic termination or the confluence of the caustic with the reflection shadow boundary (RSB). The UGO is a uniform version of the classic geometrical optics (GO). It retains the simple ray optical expressions of classic GO and employs a new set of uniform reflection coefficients. The UGO also includes a uniform version of the complex GO ray field that exists on the dark side of the smooth caustic. The EUTD is an extension of the classic uniform geometrical theory of diffraction (UTD) and accounts for the non-ray optical behavior of the UGO reflected field near caustics by using a two-variable transition function in the expressions for the edge diffraction coefficients. It also uniformly recovers the classic UTD behavior of the edge diffracted field outside the composite shadow boundary transition region. The approach employed for constructing the UGO/EUTD solution is based on a spatial domain physical optics (PO) radiation integral representation for the fields which is then reduced using uniform asymptotic procedures. The UGO/EUTD analysis is also employed to investigate the far-zone RCS problem of plane wave scattering from two and three dimensional polynomial defined surfaces, and uniform reflection, zero-curvature, and edge diffraction coefficients are derived. Numerical results for the scattering and diffraction from cubic and fourth order polynomial strips are also shown and the UGO/EUTD solution is validated by comparison to an independent moment method (MM) solution. The UGO/EUTD solution is also compared with the classic GO/UTD solution. The failure of the classic techniques near caustics and composite shadow boundaries is clearly

  17. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    Science.gov (United States)

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications.

  18. Cost-effective large-scale fabrication of diffractive optical elements by using conventional semiconducting processes.

    Science.gov (United States)

    Yoo, Seunghwan; Song, Ho Young; Lee, Junghoon; Jang, Cheol-Yong; Jeong, Hakgeun

    2012-11-20

    In this article, we introduce a simple fabrication method for SiO(2)-based thin diffractive optical elements (DOEs) that uses the conventional processes widely used in the semiconductor industry. Photolithography and an inductively coupled plasma etching technique are easy and cost-effective methods for fabricating subnanometer-scale and thin DOEs with a refractive index of 1.45, based on SiO(2). After fabricating DOEs, we confirmed the shape of the output light emitted from the laser diode light source and applied to a light-emitting diode (LED) module. The results represent a new approach to mass-produce DOEs and realize a high-brightness LED module.

  19. Generation of mask patterns for diffractive optical elements using MathematicaTM

    International Nuclear Information System (INIS)

    OShea, D.C.

    1996-01-01

    The generation of binary and grayscale masks used in the fabrication of diffractive optical elements is usually performed using a proprietary piece of software or a computer-aided drafting package. Once the pattern is computed or designed, it must be output to a plotting or imaging system that will produce a reticle plate. This article describes a number of short Mathematica modules that can be used to generate binary and grayscale patterns in a PostScript-compatible format. Approaches to ensure that the patterns are directly related to the function of the element and the design wavelength are discussed. A procedure to preserve the scale of the graphic output when it is transferred to another application is given. Examples of surfaces for a 100 mm effective focal length lens and an Alvarez surface are given. copyright 1996 American Institute of Physics

  20. Beam shaping for multicolour light-emitting diodes with diffractive optical elements

    KAUST Repository

    Yu, Chao

    2016-10-06

    An improved particle swarm optimization method is proposed for the design of ultra-thin diffractive optical elements (DOEs) enabling multicolour beam shaping functionality. We employ pre-optimized initial structures and adaptive weight strategy in the algorithm to achieve better and identical shaping performance for multiple colours. Accordingly, a DOE for shaping light from green and blue LEDs has been designed and fabricated. Both experiment and numerical simulations have been conducted and the results agree well with each other. 15.66% average root mean square error (RMSE) and 0.22% RMSE difference are achieved. In addition, the parameters closely related to the performance of the optimization are analysed, which can provide insights for future application designs.

  1. Increasing reconstruction quality of diffractive optical elements displayed with LC SLM

    Science.gov (United States)

    Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Sergey N.

    2015-03-01

    Phase liquid crystal (LC) spatial light modulators (SLM) are actively used in various applications. However, majority of scientific applications require stable phase modulation which might be hard to achieve with commercially available SLM due to its consumer origin. The use of digital voltage addressing scheme leads to phase temporal fluctuations, which results in lower diffraction efficiency and reconstruction quality of displayed diffractive optical elements (DOE). Due to high periodicity of fluctuations it should be possible to use knowledge of these fluctuations during DOE synthesis to minimize negative effect. We synthesized DOE using accurately measured phase fluctuations of phase LC SLM "HoloEye PLUTO VIS" to minimize its negative impact on displayed DOE reconstruction. Synthesis was conducted with versatile direct search with random trajectory (DSRT) method in the following way. Before DOE synthesis begun, two-dimensional dependency of SLM phase shift on addressed signal level and time from frame start was obtained. Then synthesis begins. First, initial phase distribution is created. Second, random trajectory of consecutive processing of all DOE elements is generated. Then iterative process begins. Each DOE element sequentially has its value changed to one that provides better value of objective criterion, e.g. lower deviation of reconstructed image from original one. If current element value provides best objective criterion value then it left unchanged. After all elements are processed, iteration repeats until stagnation is reached. It is demonstrated that application of SLM phase fluctuations knowledge in DOE synthesis with DSRT method leads to noticeable increase of DOE reconstruction quality.

  2. First measurements of subpicosecond electron beam structure by autocorrelation of coherent diffraction radiation

    CERN Document Server

    Lumpkin, Alex H; Rule, D W

    2001-01-01

    We report the initial measurements of subpicosecond electron beam structure using a nonintercepting technique based on the autocorrelation of coherent diffraction radiation (CDR). A far infrared (FIR) Michelson interferometer with a Golay detector was used to obtain the autocorrelation. The radiation was generated by a thermionic rf gun beam at 40 MeV as it passed through a 5-mm-tall slit/aperture in a metal screen whose surface was at 45 deg. to the beam direction. For the observed bunch lengths of about 450 fs (FWHM) with a shorter time spike on the leading edge, peak currents of about 100 A are indicated. Also a model was developed and used to calculate the CDR from the back of two metal strips separated by a 5-mm vertical gap. The demonstrated nonintercepting aspect of this method could allow on-line bunch length characterizations to be done during free-electron laser experiments.

  3. The use of holographic and diffractive optics for optimized machine vision illumination for critical dimension inspection

    Science.gov (United States)

    Lizotte, Todd E.; Ohar, Orest

    2004-02-01

    Illuminators used in machine vision applications typically produce non-uniform illumination onto the targeted surface being observed, causing a variety of problems with machine vision alignment or measurement. In most circumstances the light source is broad spectrum, leading to further problems with image quality when viewed through a CCD camera. Configured with a simple light bulb and a mirrored reflector and/or frosted glass plates, these general illuminators are appropriate for only macro applications. Over the last 5 years newer illuminators have hit the market including circular or rectangular arrays of high intensity light emitting diodes. These diode arrays are used to create monochromatic flood illumination of a surface that is to be inspected. The problem with these illumination techniques is that most of the light does not illuminate the desired areas, but broadly spreads across the surface, or when integrated with diffuser elements, tend to create similar shadowing effects to the broad spectrum light sources. In many cases a user will try to increase the performance of these illuminators by adding several of these assemblies together, increasing the intensity or by moving the illumination source closer or farther from the surface being inspected. In this case these non-uniform techniques can lead to machine vision errors, where the computer machine vision may read false information, such as interpreting non-uniform lighting or shadowing effects as defects. This paper will cover a technique involving the use of holographic / diffractive hybrid optical elements that are integrated into standard and customized light sources used in the machine vision industry. The bulk of the paper will describe the function and fabrication of the holographic/diffractive optics and how they can be tailored to improve illuminator design. Further information will be provided a specific design and examples of it in operation will be disclosed.

  4. Optical radiation, with particular reference to lasers

    International Nuclear Information System (INIS)

    Goldman, L.; Michaelson, S.M.; Rockwell, R.J.; Sliney, D.H.; Tengroth, B.M.; Wolbarsht, M.L.

    1989-01-01

    Laser emissions cover wavelengths from 10 nm to 1 mm and are used in a wide variety of applications. The interactions between biological tissues and laser radiation depend on irradiance and radiant exposure, exposure duration and wavelength. Because of the relatively superficial absorption, the major biological effects are on the skin and the eye. The health hazards to the skin are both acute (thermal burns, sunburn, photosensitized reactions) and chronic (accelerated aging and photocarcinogenesis). The main health hazards to the eye are photokeratitis, corneal burns, photochemical and thermal cataract, ocular inflammation, and photo-chemical, thermal and thermo-acoustic retinal injury and optical breakdown within the eye. Secondary haemorrhage in the vitreous humour with complete loss of vision could be produced by severe damage to the retina. 59 refs, 6 figs, 8 tabs

  5. Neutron diffraction measurements at the INES diffractometer using a neutron radiative capture based counting technique

    Energy Technology Data Exchange (ETDEWEB)

    Festa, G. [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Pietropaolo, A., E-mail: antonino.pietropaolo@roma2.infn.it [Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); Grazzi, F.; Barzagli, E. [CNR-ISC Firenze (Italy); Scherillo, A. [CNR-ISC Firenze (Italy); ISIS facility Rutherford Appleton Laboratory (United Kingdom); Schooneveld, E.M. [ISIS facility Rutherford Appleton Laboratory (United Kingdom)

    2011-10-21

    The global shortage of {sup 3}He gas is an issue to be addressed in neutron detection. In the context of the research and development activity related to the replacement of {sup 3}He for neutron counting systems, neutron diffraction measurements performed on the INES beam line at the ISIS pulsed spallation neutron source are presented. For these measurements two different neutron counting devices have been used: a 20 bar pressure squashed {sup 3}He tube and a Yttrium-Aluminum-Perovskite scintillation detector. The scintillation detector was coupled to a cadmium sheet that registers the prompt radiative capture gamma rays generated by the (n,{gamma}) nuclear reactions occurring in cadmium. The assessment of the scintillator based counting system was done by performing a Rietveld refinement analysis on the diffraction pattern from an ancient Japanese blade and comparing the results with those obtained by a {sup 3}He tube placed at the same angular position. The results obtained demonstrate the considerable potential of the proposed counting approach based on the radiative capture gamma rays at spallation neutron sources.

  6. On the structural-optical correlations in radiation-modified chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kavetskyy, T; Tsmots, V [Solid State Microelectronics Laboratory, Drohobych Ivan Franko State Pedagogical University, 24 I. Franko Str., Drohobych, 82100 (Ukraine); Kaban, I; Hoyer, W [Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz (Germany); Shpotyuk, O, E-mail: kavetskyy@yahoo.com [Institute of Materials, Scientific Research Company ' Carat' , 202 Stryjska Str., Lviv, 79031 (Ukraine)

    2011-04-01

    In this work, we report our recent results on the gamma-irradiation-induced structural transformations in the Ge-Sb-S glasses as observed from the structural studies using high-energy synchrotron x-ray diffraction and extended x-ray absorption fine structure spectroscopy in comparison with the optical measurements using VIS/IR spectroscopy techniques. The structural-optical correlations in the radiation-induced effects are established. The structural changes upon irradiation are explained in the frames of the concept of coordination topological defects formation.

  7. On the structural-optical correlations in radiation-modified chalcogenide glasses

    International Nuclear Information System (INIS)

    Kavetskyy, T; Tsmots, V; Kaban, I; Hoyer, W; Shpotyuk, O

    2011-01-01

    In this work, we report our recent results on the gamma-irradiation-induced structural transformations in the Ge-Sb-S glasses as observed from the structural studies using high-energy synchrotron x-ray diffraction and extended x-ray absorption fine structure spectroscopy in comparison with the optical measurements using VIS/IR spectroscopy techniques. The structural-optical correlations in the radiation-induced effects are established. The structural changes upon irradiation are explained in the frames of the concept of coordination topological defects formation.

  8. New experimental diffractive-optical data on E.Land's Retinex mechanism in human color vision: Part II

    Science.gov (United States)

    Lauinger, N.

    2007-09-01

    A better understanding of the color constancy mechanism in human color vision [7] can be reached through analyses of photometric data of all illuminants and patches (Mondrians or other visible objects) involved in visual experiments. In Part I [3] and in [4, 5 and 6] the integration in the human eye of the geometrical-optical imaging hardware and the diffractive-optical hardware has been described and illustrated (Fig.1). This combined hardware represents the main topic of the NAMIROS research project (nano- and micro- 3D gratings for optical sensors) [8] promoted and coordinated by Corrsys 3D Sensors AG. The hardware relevant to (photopic) human color vision can be described as a diffractive or interference-optical correlator transforming incident light into diffractive-optical RGB data and relating local RGB onto global RGB data in the near-field behind the 'inverted' human retina. The relative differences at local/global RGB interference-optical contrasts are available to photoreceptors (cones and rods) only after this optical pre-processing.

  9. Optical camera system for radiation field

    International Nuclear Information System (INIS)

    Maki, Koichi; Senoo, Makoto; Takahashi, Fuminobu; Shibata, Keiichiro; Honda, Takuro.

    1995-01-01

    An infrared-ray camera comprises a transmitting filter used exclusively for infrared-rays at a specific wavelength, such as far infrared-rays and a lens used exclusively for infrared rays. An infrared ray emitter-incorporated photoelectric image converter comprising an infrared ray emitting device, a focusing lens and a semiconductor image pick-up plate is disposed at a place of low gamma-ray dose rate. Infrared rays emitted from an objective member are passed through the lens system of the camera, and real images are formed by way of the filter. They are transferred by image fibers, introduced to the photoelectric image converter and focused on the image pick-up plate by the image-forming lens. Further, they are converted into electric signals and introduced to a display and monitored. With such a constitution, an optical material used exclusively for infrared rays, for example, ZnSe can be used for the lens system and the optical transmission system. Accordingly, it can be used in a radiation field of high gamma ray dose rate around the periphery of the reactor container. (I.N.)

  10. Radiation distribution sensing with normal optical fiber

    CERN Document Server

    Kawarabayashi, J; Naka, R; Uritani, A; Watanabe, K I; Iguchi, T; Tsujimura, N

    2002-01-01

    The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length (10m-100m) and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The characteristics of this monitor to beta particles, gamma rays and fast neutrons were obtained. The spatial resolutions for beta particles ( sup 9 sup 0 Sr sup - sup 9 sup 0 Y), gamma rays ( sup 1 sup 3 sup 7 Cs) and D-T neutrons were 30 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the gamma rays and D-T neutrons were 0.11%, 1.6x10 sup - sup 5 % and 5.4x10 sup - sup 4 %, respectively. The effective attenuation length of the detection efficiency was 18m. New principle of the position sensing based on spectroscopic analysis was also proposed. A preliminary test showed that the spectrum observed at the end of the fiber depended on the position of the irradiated point. This fact shows that t...

  11. Identification of copper-based green pigments in Jaume Huguet's Gothic altarpieces by Fourier transform infrared microspectroscopy and synchrotron radiation X-ray diffraction.

    Science.gov (United States)

    Salvadó, N; Pradell, T; Pantos, E; Papiz, M Z; Molera, J; Seco, M; Vendrell-Saz, M

    2002-07-01

    The scientific investigation of ancient paintings gives a unique insight into ancient painting techniques and their evolution through time and geographic location. This study deals with the identification of the green pigments used by one of the most important Catalan masters in Gothic times, Jaume Huguet. Other pigments and materials have also been characterized by means of conventional techniques such as optical microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. Synchrotron radiation X-ray diffraction has been used to produce maps of phases at a spatial resolution of 100 microm across chromatic layers.

  12. Mechanical reliability assessment of optical fibres in Radiation environments

    International Nuclear Information System (INIS)

    Van Uffelen, M.

    2006-01-01

    After more than two decades of intensive research and even some pioneering applications in space, optical fibres are now finding their way in various radiation environments, including both fission and future fusion nuclear-power plants, and high-energy physics experiments. For example, next to distributed monitoring applications of large nuclear infrastructures, fibre-optics can also be used for data communications during maintenance operations in the reactor vessel of the future ITER (International Thermonuclear Experimental Reactor), or for plasma diagnostics applications during operation of the reactor. These maintenance and diagnostics tasks require the optical fibres to withstand extremely high doses of radiation, up to MGy dose levels and temperatures above 150 degrees Celsius. The reliability assessment of fibre-optic systems for their qualification in nuclear environments often requires to meet stringent radiation tolerance levels. The majority of (usually accelerated) radiation assessments have so far focused on optical properties, such as wavelength-dependent radiation induced attenuation and radio-luminescence. The relation of these radiation effects with the fabrication methods and other environmental parameters has been the subject of years of research. Only a few results are available on the long-term evolution of mechanical properties of irradiated optical fibres. As a first step towards understanding the long-term reliability of fibre-optic composite cables in hostile radiation environments, we therefore performed dynamic fatigue tests with different commercial-grade optical fibres, both multi-mode and single-mode types

  13. Micromachined diffraction based optical microphones and intensity probes with electrostatic force feedback

    Science.gov (United States)

    Bicen, Baris

    Measuring acoustic pressure gradients is critical in many applications such as directional microphones for hearing aids and sound intensity probes. This measurement is especially challenging with decreasing microphone size, which reduces the sensitivity due to small spacing between the pressure ports. Novel, micromachined biomimetic microphone diaphragms are shown to provide high sensitivity to pressure gradients on one side of the diaphragm with low thermal mechanical noise. These structures have a dominant mode shape with see-saw like motion in the audio band, responding to pressure gradients as well as spurious higher order modes sensitive to pressure. In this dissertation, integration of a diffraction based optical detection method with these novel diaphragm structures to implement a low noise optical pressure gradient microphone is described and experimental characterization results are presented, showing 36 dBA noise level with 1mm port spacing, nearly an order of magnitude better than the current gradient microphones. The optical detection scheme also provides electrostatic actuation capability from both sides of the diaphragm separately which can be used for active force feedback. A 4-port electromechanical equivalent circuit model of this microphone with optical readout is developed to predict the overall response of the device to different acoustic and electrostatic excitations. The model includes the damping due to complex motion of air around the microphone diaphragm, and it calculates the detected optical signal on each side of the diaphragm as a combination of two separate dominant vibration modes. This equivalent circuit model is verified by experiments and used to predict the microphone response with different force feedback schemes. Single sided force feedback is used for active damping to improve the linearity and the frequency response of the microphone. Furthermore, it is shown that using two sided force feedback one can significantly suppress

  14. Switching waves dynamics in optical bistable cavity-free system at femtosecond laser pulse propagation in semiconductor under light diffraction

    Science.gov (United States)

    Trofimov, Vyacheslav A.; Egorenkov, Vladimir A.; Loginova, Maria M.

    2018-02-01

    We consider a propagation of laser pulse in a semiconductor under the conditions of an occurrence of optical bistability, which appears due to a nonlinear absorption of the semiconductor. As a result, the domains of high concentration of free charged particles (electrons and ionized donors) occur if an intensity of the incident optical pulse is greater than certain intensity. As it is well-known, that an optical beam must undergo a diffraction on (or reflection from) the domains boundaries. Usually, the beam diffraction along a coordinate of the optical pulse propagation does not take into account by using the slowly varying envelope approximation for the laser pulse interaction with optical bistable element. Therefore, a reflection of the beam from the domains with abrupt boundary does not take into account under computer simulation of the laser pulse propagation. However, the optical beams, reflected from nonhomogeneities caused by the domains of high concentration of free-charged particles, can essentially influence on a formation of switching waves in a semiconductor. We illustrate this statement by computer simulation results provided on the base of nonlinear Schrödinger equation and a set of PDEs, which describe an evolution of the semiconductor characteristics (concentrations of free-charged particles and potential of an electric field strength), and taking into account the longitudinal and transverse diffraction effects.

  15. Radiation optic neuropathy after external beam radiation therapy for acromegaly: report of two cases

    International Nuclear Information System (INIS)

    Bergh, Alfons C.M. van den; Hoving, Marjanke A.; Links, Thera P.; Dullaart, Robin P.F.; Ranchor, Adelita V.; Weeme, Cees A. ter; Canrinus, Alof A.; Szabo, Ben G.; Pott, Jan-Willem R.

    2003-01-01

    For diagnosing radiation optic neuropathy (RON) ophthalmological and imaging data were evaluated from 63 acromegalic patients, irradiated between 1967 and 1998. Two patients developed RON: one patient in one optic nerve 10 years and another patient in both optic nerves 5 months after radiation therapy. RON is a rare complication after external beam radiation therapy for acromegaly, which can occur after a considerable latency period

  16. X-radiation damage of hydrated lecithin membranes detected by real-time X-ray diffraction using wiggler-enhanced synchrotron radiation as the ionizing radiation source

    International Nuclear Information System (INIS)

    Caffrey, M.; Cornell Univ., Ithaca, NY

    1984-01-01

    Radiation damage of hydrated lecithin membranes brought about by exposure to wiggler-derived synchrotron radiation at 8.3 keV (1.5 A) is reported. Considerable damage was observed with exposures under 1 h at an incident flux density of 3 x 10 10 photons s -1 mm -2 , corresponding to a cumulative radiation dose of <= 10 MRad. Damage was so dramatic as to be initially observed while making real-time X-ray diffraction measurements on the sample. The damaging effects of 8.3 keV X-rays on dispersions of dipalmitoyllecithin and lecithin derived from hen egg yolk are as follows: (1) marked changes were noted in the X-ray diffraction behaviour, indicating disruption of membrane stacking. (2) Chemical breakdown of lecithin was observed. (3) The X-ray beam visibly damaged the sample and changed the appearance of the lipid dispersion, when viewed under the light microscope. Considering the importance of X-ray diffraction as a structural probe and the anticipated use of synchrotron radiation in studies involving membranes, the problem of radiation damage must be duly recognized. Furthermore, since dipalmitoyllecithin, the major lipid used in the present study, is a relatively stable compound, it is not unreasonable to expect that X-ray damage may be a problem with other less stable biological and non-biological materials. These results serve to emphasize that whenever a high intensity X-ray source is used, radiation damage can be a problem and that the sensitivity of the sample must always be evaluated under the conditions of measurement. (orig.)

  17. High-power fiber laser with a polarizing diffraction grating milled on the facet of an optical fiber

    Czech Academy of Sciences Publication Activity Database

    Vaněk, Martin; Vaniš, Jan; Baravets, Yauhen; Todorov, Filip; Čtyroký, Jiří; Honzátko, Pavel

    2016-01-01

    Roč. 24, č. 26 (2016), s. 30225-30233 ISSN 1094-4087 R&D Projects: GA ČR GA15-07908S Institutional support: RVO:67985882 Keywords : Optical fibers * Polarization * Diffraction gratings Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.307, year: 2016

  18. High-power fiber laser with a polarizing diffraction grating milled on the facet of an optical fiber

    Czech Academy of Sciences Publication Activity Database

    Vaněk, Martin; Vaniš, Jan; Baravets, Yauhen; Todorov, Filip; Čtyroký, Jiří; Honzátko, Pavel

    2016-01-01

    Roč. 24, č. 26 (2016), s. 30225-30233 ISSN 1094-4087 R&D Projects: GA ČR GA15-07908S Institutional support: RVO:67985882 Keywords : Optical fiber s * Polarization * Diffraction gratings Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.307, year: 2016

  19. Time-resolved x-ray diffraction measurement of C60 under high pressure and temperature using synchrotron radiation

    International Nuclear Information System (INIS)

    Horikawa, T; Suito, K; Kobayashi, M; Onodera, A

    2002-01-01

    C 60 has been studied by means of time-resolved x-ray diffraction measurements using synchrotron radiation. Diffraction patterns were recorded at intervals of 1-10 min for samples under high pressure (12.5 and 14.3 GPa) and high temperature (up to 800 deg. C) for, at the longest, 3 h. Time, pressure, and temperature dependences of the C 60 structure are presented and the relevance to the hardness of materials derived from C 60 is discussed

  20. Optical Imaging of Ionizing Radiation from Clinical Sources.

    Science.gov (United States)

    Shaffer, Travis M; Drain, Charles Michael; Grimm, Jan

    2016-11-01

    Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  1. High-pressure X-ray diffraction experiments on US using synchrotron radiation

    International Nuclear Information System (INIS)

    Olsen, J.S.; Steenstrup, S.

    1983-12-01

    High-pressure X-ray diffraction studies have been performed on US up to 40 GPa using synchrotron radiation and a diamond anvil cell. The measured value of the bulk modulus B 0 = 92 GPa is in reasonable agreement with calculations. The high-pressure behaviour indicates a phase transformation to US III at about 15 GPa. The transformation is a smooth deformation process, which starts with a tetragonal structure asub(tetr) = asub(cub)/√2, csub(tetr) = 2asub(cub) and continues with an orthorhombic structure with a = 375(3)pm, b = 345(3)pm, c = 1069 (24)pm at 35 GPa; it is of second order nature within experimental errors and it should involve some contributions from uranium f electrons. (orig.)

  2. Preliminary study of a phase transformation in insulin crystals using synchrotron-radiation Laue diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, C D; Stowell, B; Joshi, K K; Harding, M M; Maginn, S J; Dodson, G G

    1988-10-01

    Synchrotron-radiation Laue diffraction photographs have been recorded showing the transformation of single 4Zn insulin crystals (a=80.7 (1), c=37.6 (1) A, space group R3) to 2Zn insulin (a=82.5 (1), c=34.0 (1) A, space group R3). The transformation was brought about by changing the mother liquor in the capillary in which the crystal was mounted. Photographs were taken at 10 min intervals (exposure time 3 s) from 0.5 h after mounting. They showed initially a well ordered 4Zn insulin crystal (d/sub min/ ca 2.3 A), then a poorly ordered, sometimes multiple, crystal, and finally a 2Zn insulin crystal, about as well ordered as the initial crystal.

  3. Optical diffraction tomography microscopy with transport of intensity equation using a light-emitting diode array

    Science.gov (United States)

    Li, Jiaji; Chen, Qian; Zhang, Jialin; Zhang, Zhao; Zhang, Yan; Zuo, Chao

    2017-08-01

    Optical diffraction tomography (ODT) is an effective label-free technique for quantitatively refractive index imaging, which enables long-term monitoring of the internal three-dimensional (3D) structures and molecular composition of biological cells with minimal perturbation. However, existing optical tomographic methods generally rely on interferometric configuration for phase measurement and sophisticated mechanical systems for sample rotation or beam scanning. Thereby, the measurement is suspect to phase error coming from the coherent speckle, environmental vibrations, and mechanical error during data acquisition process. To overcome these limitations, we present a new ODT technique based on non-interferometric phase retrieval and programmable illumination emitting from a light-emitting diode (LED) array. The experimental system is built based on a traditional bright field microscope, with the light source replaced by a programmable LED array, which provides angle-variable quasi-monochromatic illumination with an angular coverage of ±37 degrees in both x and y directions (corresponding to an illumination numerical aperture of ∼0.6). Transport of intensity equation (TIE) is utilized to recover the phase at different illumination angles, and the refractive index distribution is reconstructed based on the ODT framework under first Rytov approximation. The missing-cone problem in ODT is addressed by using the iterative non-negative constraint algorithm, and the misalignment of the LED array is further numerically corrected to improve the accuracy of refractive index quantification. Experiments on polystyrene beads and thick biological specimens show that the proposed approach allows accurate refractive index reconstruction while greatly reduced the system complexity and environmental sensitivity compared to conventional interferometric ODT approaches.

  4. Sequential x-ray diffraction topography at 1-BM x-ray optics testing beamline at the advanced photon source

    Energy Technology Data Exchange (ETDEWEB)

    Stoupin, Stanislav, E-mail: sstoupin@aps.anl.gov; Shvyd’ko, Yuri; Trakhtenberg, Emil; Liu, Zunping; Lang, Keenan; Huang, Xianrong; Wieczorek, Michael; Kasman, Elina; Hammonds, John; Macrander, Albert; Assoufid, Lahsen [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2016-07-27

    We report progress on implementation and commissioning of sequential X-ray diffraction topography at 1-BM Optics Testing Beamline of the Advanced Photon Source to accommodate growing needs of strain characterization in diffractive crystal optics and other semiconductor single crystals. The setup enables evaluation of strain in single crystals in the nearly-nondispersive double-crystal geometry. Si asymmetric collimator crystals of different crystallographic orientations were designed, fabricated and characterized using in-house capabilities. Imaging the exit beam using digital area detectors permits rapid sequential acquisition of X-ray topographs at different angular positions on the rocking curve of a crystal under investigation. Results on sensitivity and spatial resolution are reported based on experiments with high-quality Si and diamond crystals. The new setup complements laboratory-based X-ray topography capabilities of the Optics group at the Advanced Photon Source.

  5. Four cases of radiation retinopathy and optic neuropathy

    International Nuclear Information System (INIS)

    Konari, Kenji; Suzuki, Jun-ichi; Nakagawa, Takashi

    1996-01-01

    We observed retinopathy and optic neuropathy in 4 patients after radiation for malignancies in the paranasal sinus or the brain. The dosis ranged from 56 Gy for 14 days to 64 Gy for 32 days. The interval between the termination of radiation and onset of fundus lesions ranged from 1 to 36 months, average 16.6 months. The retinopathy appeared as retinal hemorrhage, soft exudates and vitreous hemorrhage. Neovascular glaucoma developed in one eye. The optic neuropathy appeared as pallor of optic disc, disc edema or optic papillitis. Histological studies of one eye with retinopathy showed thickening of retinal capillary walls and rubeosis iridis with angle closure. (author)

  6. Four cases of radiation retinopathy and optic neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Konari, Kenji; Suzuki, Jun-ichi; Nakagawa, Takashi [Sapporo Medical Coll. (Japan)

    1996-03-01

    We observed retinopathy and optic neuropathy in 4 patients after radiation for malignancies in the paranasal sinus or the brain. The dosis ranged from 56 Gy for 14 days to 64 Gy for 32 days. The interval between the termination of radiation and onset of fundus lesions ranged from 1 to 36 months, average 16.6 months. The retinopathy appeared as retinal hemorrhage, soft exudates and vitreous hemorrhage. Neovascular glaucoma developed in one eye. The optic neuropathy appeared as pallor of optic disc, disc edema or optic papillitis. Histological studies of one eye with retinopathy showed thickening of retinal capillary walls and rubeosis iridis with angle closure. (author).

  7. Optical electromagnetic vector-field modeling for the accurate analysis of finite diffractive structures of high complexity

    DEFF Research Database (Denmark)

    Dridi, Kim; Bjarklev, Anders Overgaard

    1999-01-01

    An electromagnetic vector-field modle for design of optical components based on the finite-difference-time-domain method and radiation integrals in presented. Its ability to predict the optical electromagnetic dynamics in structures with complex material distribution is demonstrated. Theoretical...

  8. Program description of FIBRAM (Fiber Optic Radiation Attenuation Model): a radiation attenuation model for optical fibers

    International Nuclear Information System (INIS)

    Ingram, W.J.

    1987-06-01

    The report describes a fiber-optics system model and its computer implementation. This implementation can calculate the bit error ratio (BER) versus time for optical fibers that have been exposed to gamma radiation. The program is designed so that the user may arbitrarily change any or all of the system input variables and produce separate outputs. The primary output of the program is a table of the BER as a function of time. This table may be stored on magnetic media and later incorporated into computer graphic programs. The program was written in FORTRAN 77 for the IBM PC/AT/XT computers. Flow charts and program listings are included in the report

  9. Optical fibers and their applications for radiation measurements

    International Nuclear Information System (INIS)

    Kakuta, Tsunemi

    1998-01-01

    When optical fibers are used in a strong radiation field, it is necessary to increase the radiation-resistant capacity. Aiming at the improvement of such property, the characteristics of recent optical fibers made from quartz-glass were reviewed and the newly developed techniques for radiation measurement using those fibers were summarized in this report. Since optical fibers became able to use in the levels near the core conditions, their applications have started in various fields of technologies related to radiation. By combining the optical fibers and a small sensor, it became possible to act as 'Key Component' for measuring wide range radioactivity from a trace activity to a strong radiation field in the reactor core. Presently, the fibers are utilized for investigation of the optical mechanisms related in radiation, evaluation of their validities so on. Further, the optical fibers are expected to utilize in a multi-parametric measuring system which allows to concomitantly determine the radiation, temperature, pressure, flow amount etc. as an incore monitor. (M.N.)

  10. Optical fibers and their applications for radiation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kakuta, Tsunemi [Japan Atomic Energy Research Inst., Tokyo (Japan)

    1998-07-01

    When optical fibers are used in a strong radiation field, it is necessary to increase the radiation-resistant capacity. Aiming at the improvement of such property, the characteristics of recent optical fibers made from quartz-glass were reviewed and the newly developed techniques for radiation measurement using those fibers were summarized in this report. Since optical fibers became able to use in the levels near the core conditions, their applications have started in various fields of technologies related to radiation. By combining the optical fibers and a small sensor, it became possible to act as `Key Component` for measuring wide range radioactivity from a trace activity to a strong radiation field in the reactor core. Presently, the fibers are utilized for investigation of the optical mechanisms related in radiation, evaluation of their validities so on. Further, the optical fibers are expected to utilize in a multi-parametric measuring system which allows to concomitantly determine the radiation, temperature, pressure, flow amount etc. as an incore monitor. (M.N.)

  11. Serial Diffusion Tensor Imaging of the Optic Radiations after Acute Optic Neuritis

    Directory of Open Access Journals (Sweden)

    Scott C. Kolbe

    2016-01-01

    Full Text Available Previous studies have reported diffusion tensor imaging (DTI changes within the optic radiations of patients after optic neuritis (ON. We aimed to study optic radiation DTI changes over 12 months following acute ON and to study correlations between DTI parameters and damage to the optic nerve and primary visual cortex (V1. We measured DTI parameters [fractional anisotropy (FA, axial diffusivity (AD, radial diffusivity (RD, and mean diffusivity (MD] from the optic radiations of 38 acute ON patients at presentation and 6 and 12 months after acute ON. In addition, we measured retinal nerve fibre layer thickness, visual evoked potential amplitude, optic radiation lesion load, and V1 thickness. At baseline, FA was reduced and RD and MD were increased compared to control. Over 12 months, FA reduced in patients at an average rate of −2.6% per annum (control = −0.51%; p=0.006. Change in FA, RD, and MD correlated with V1 thinning over 12 months (FA: R=0.450, p=0.006; RD: R=-0.428, p=0.009; MD: R=-0.365, p=0.029. In patients with no optic radiation lesions, AD significantly correlated with RNFL thinning at 12 months (R=0.489, p=0.039. In conclusion, DTI can detect optic radiation changes over 12 months following acute ON that correlate with optic nerve and V1 damage.

  12. Review of high bandwidth fiber optics radiation sensors

    International Nuclear Information System (INIS)

    Lyons, P.B.

    1985-01-01

    This paper summarizes the use of fiber optics or guided optical systems for radiation sensors. It is limited a passive systems wherein electrical is not required at the sensor location. However, electrically powered light sources, receivers and/or recorders may still be required for detection and data storage in sensor system operation. This paper emphasizes sensor technologies that permit high bandwidth measurements of transient radiation levels, and will also discuss several low bandwidth applications. 60 refs

  13. Revisiting Bragg's X-ray microscope: Scatter based optical transient grating detection of pulsed ionising radiation

    International Nuclear Information System (INIS)

    Fullagar, Wilfred K.; Paganin, David M.; Hall, Chris J.

    2011-01-01

    Transient optical gratings for detecting ultrafast signals are routine for temporally resolved photochemical investigations. Many processes can contribute to the formation of such gratings; we indicate use of optically scattering centres that can be formed with highly variable latencies in different materials and devices using ionising radiation. Coherent light scattered by these centres can form the short-wavelength-to-optical-wavelength, incoherent-to-coherent basis of a Bragg X-ray microscope, with inherent scope for optical phasing. Depending on the dynamics of the medium chosen, the way is open to both ultrafast pulsed and integrating measurements. For experiments employing brief pulses, we discuss high-dynamic-range short-wavelength diffraction measurements with real-time optical reconstructions. Applications to optical real-time X-ray phase-retrieval are considered. -- Research highlights: → It is timely that the concept of Bragg's X-ray microscope be revisited. → Transient gratings can be used for X-ray all-optical information processing. → Applications to optical real-time X-ray phase-retrieval are considered.

  14. Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation.

    Science.gov (United States)

    Hrdý, Jaromír; Mikulík, Petr; Oberta, Peter

    2011-03-01

    A new kind of two channel-cut crystals X-ray monochromator in dispersive (+,-,-,+) position which spatially separates harmonics is proposed. The diffracting surfaces are oriented so that the diffraction is inclined. Owing to refraction the diffracted beam is sagittally deviated. The deviation depends on wavelength and is much higher for the first harmonics than for higher harmonics. This leads to spatial harmonics separation. The idea is supported by ray-tracing simulation.

  15. Intensity of diffracted X-rays from biomolecules with radiation damage caused by strong X-ray pulses

    International Nuclear Information System (INIS)

    Kai, Takeshi; Tokuhisa, Atsushi; Moribayashi, Kengo; Fukuda, Yuji; Kono, Hidetoshi; Go, Nobuhiro

    2014-01-01

    In order to realize the coherent X-ray diffractive imaging of single biomolecules, the diffraction intensities, per effective pixel of a single biomolecule with radiation damage, caused by irradiation using a strong coherent X-ray pulse, were examined. A parameter survey was carried out for various experimental conditions, using a developed simulation program that considers the effect of electric field ionization, which was slightly reported on in previous studies. The two simple relationships among the parameters were identified as follows: (1) the diffraction intensity of a biomolecule slightly increases with the incident X-ray energy; and that (2) the diffraction intensity is approximately proportional to the target radius, when the radius is longer than 400 Å, since the upper limit of the incident intensity for damage to the biomolecules marginally changes with respect to the target radius. (author)

  16. X-ray diffraction studies on single and mixed confectionery fats using synchrotron radiation

    International Nuclear Information System (INIS)

    MacMillan, S.C.; Roberts, K.J.; Wells, M.; Polgreen, M.; Smith, I.

    1999-01-01

    Full text: Understanding and refining the molecular-scale processes involved in the manufacture of structured materials such as long-chain hydrocarbon compounds is important in many commercial areas such as the petrochemical, biochemical, food, pharmaceutical and soap industries. In such processes crystallisation is an important separation, purification and preparation technique. Despite this our knowledge of the crystallisation process itself is surprisingly limited. In order to improve the crystallisation of confectionery fats, the crystallisation of it's main component, cocoa butter fat, must be properly understood. Cocoa butter fat can exhibit up to 6 polymorphic forms of different crystallographic structures with melting points varying from 17.3 deg C to 36.3 deg C. During the production of chocolate it is essential to control the polymorphic form of fats present, in order to produce a final product with the correct physical and rheological properties. Both shear rate and temperature are thought to play a crucial role in this process. The most widely used method for studying polymorphism is X-ray diffraction. Typical X-ray diffraction patterns of fats exhibit two groups of diffraction lines corresponding to the long and short spacings. The long spacings correspond to the planes formed by the methyl end groups and are dependent on the chain length and the angle of tilt of the component fatty acids of the glyceride molecules. The short spacings refer to the cross sectional packing of the hydrocarbon chain and are independent of the chain length. The relationship between crystallisation rate, polymorphic form, shear and the fat composition has for the first time been quantified, which will enable more accurate control of the polymorhic form in chocolate production. This has been achieved by developing an improved in-situ cell for X-ray studies. The X-ray studies are necessary for the examination of on-line studies under well controlled conditions of temperature

  17. X-ray diffraction studies on single and mixed confectionery fats using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    MacMillan, S.C.; Roberts, K.J.; Wells, M.; Polgreen, M.; Smith, I. [Heriot-Watt University, Edinburgh, (United Kingdom). Department of Mechanical and Chemical Engineering, Centre for Molecular and Interface Engineering

    1999-12-01

    Full text: Understanding and refining the molecular-scale processes involved in the manufacture of structured materials such as long-chain hydrocarbon compounds is important in many commercial areas such as the petrochemical, biochemical, food, pharmaceutical and soap industries. In such processes crystallisation is an important separation, purification and preparation technique. Despite this our knowledge of the crystallisation process itself is surprisingly limited. In order to improve the crystallisation of confectionery fats, the crystallisation of it`s main component, cocoa butter fat, must be properly understood. Cocoa butter fat can exhibit up to 6 polymorphic forms of different crystallographic structures with melting points varying from 17.3 deg C to 36.3 deg C. During the production of chocolate it is essential to control the polymorphic form of fats present, in order to produce a final product with the correct physical and rheological properties. Both shear rate and temperature are thought to play a crucial role in this process. The most widely used method for studying polymorphism is X-ray diffraction. Typical X-ray diffraction patterns of fats exhibit two groups of diffraction lines corresponding to the long and short spacings. The long spacings correspond to the planes formed by the methyl end groups and are dependent on the chain length and the angle of tilt of the component fatty acids of the glyceride molecules. The short spacings refer to the cross sectional packing of the hydrocarbon chain and are independent of the chain length. The relationship between crystallisation rate, polymorphic form, shear and the fat composition has for the first time been quantified, which will enable more accurate control of the polymorhic form in chocolate production. This has been achieved by developing an improved in-situ cell for X-ray studies. The X-ray studies are necessary for the examination of on-line studies under well controlled conditions of temperature

  18. Dynamic diffraction-limited light-coupling of 3D-maneuvered wave-guided optical waveguides.

    Science.gov (United States)

    Villangca, Mark; Bañas, Andrew; Palima, Darwin; Glückstad, Jesper

    2014-07-28

    We have previously proposed and demonstrated the targeted-light delivery capability of wave-guided optical waveguides (WOWs). As the WOWs are maneuvered in 3D space, it is important to maintain efficient light coupling through the waveguides within their operating volume. We propose the use of dynamic diffractive techniques to create diffraction-limited spots that will track and couple to the WOWs during operation. This is done by using a spatial light modulator to encode the necessary diffractive phase patterns to generate the multiple and dynamic coupling spots. The method is initially tested for a single WOW and we have experimentally demonstrated dynamic tracking and coupling for both lateral and axial displacements.

  19. Dynamic diffraction-limited light-coupling of 3D-maneuvered wave-guided optical waveguides

    DEFF Research Database (Denmark)

    Villangca, Mark Jayson; Bañas, Andrew Rafael; Palima, Darwin

    2014-01-01

    We have previously proposed and demonstrated the targeted-light delivery capability of wave-guided optical waveguides (WOWs). As the WOWs are maneuvered in 3D space, it is important to maintain efficient light coupling through the waveguides within their operating volume. We propose the use...... of dynamic diffractive techniques to create diffraction-limited spots that will track and couple to the WOWs during operation. This is done by using a spatial light modulator to encode the necessary diffractive phase patterns to generate the multiple and dynamic coupling spots. The method is initially tested...... for a single WOW and we have experimentally demonstrated dynamic tracking and coupling for both lateral and axial displacements....

  20. Observation of optical Smith-Purcell radiation at an electron beam energy of 855 MeV

    International Nuclear Information System (INIS)

    Kube, G.; Backe, H.; Euteneuer, H.; Grendel, A.; Hagenbuck, F.; Hartmann, H.; Kaiser, K.H.; Lauth, W.; Schoepe, H.; Wagner, G.; Walcher, Th.; Kretzschmar, M.

    2002-01-01

    Smith-Purcell radiation, generated when a beam of charged particles passes close to the surface of a diffraction grating, has been studied in the visible spectral range at wavelengths of 360 and 546 nm with the low emittance 855 MeV electron beam of the Mainz Microtron MAMI. The beam focused to a spot size of 4 μm (full width at half maximum) passed over optical diffraction gratings of echelle profiles with blaze angles of 0.8 deg., 17.27 deg., and 41.12 deg. and grating periods of 0.833 and 9.09 μm. Taking advantage of the specific emission characteristics of Smith-Purcell radiation a clear separation from background components, such as diffracted synchrotron radiation from upstream beam optical elements and transition radiation, was possible. The intensity scales with a modified Bessel function of the first kind as a function of the distance between electron beam and grating surface. Experimental radiation factors have been determined and compared with calculations on the basis of Van den Berg's theory [P.M. Van den Berg, J. Opt. Soc. Am. 63, 689 (1973)]. Fair agreement has been found for gratings with large blaze angles while the measurement with the shallow grating (blaze angle 0.8 deg.) is at variance with this theory. Finally, the optimal operational parameters of a Smith-Purcell radiation source in view of already existing powerful undulator sources are discussed

  1. Effect of gamma radiation on optical and electrical properties of ...

    Indian Academy of Sciences (India)

    Wintec

    Tellurium dioxide; thin films; optical bandgap; gamma radiation dose; dosimeter. 1. Introduction. It is now ... material to ionizing radiations (such as X-rays, gamma rays, beta ..... Mag. 19 19. Mott N F and Davis E 1979 Electronic process in non-.

  2. Subreflector extension for improved efficiencies in Cassegrain antennas - GTD/PO analysis. [Geometrical Theory of Diffraction/Physical Optics

    Science.gov (United States)

    Rahmat-Samii, Yahya

    1986-01-01

    Both offset and symmetric Cassegrain reflector antennas are used in satellite and ground communication systems. It is known that the subreflector diffraction can degrade the performance of these reflectors. A geometrical theory of diffraction/physical optics analysis technique is used to investigate the effects of the extended subreflector, beyond its optical rim, on the reflector efficiency and far-field patterns. Representative numerical results are shown for an offset Cassegrain reflector antenna with different feed illumination tapers and subreflector extensions. It is observed that for subreflector extensions as small as one wavelength, noticeable improvements in the overall efficiencies can be expected. Useful design data are generated for the efficiency curves and far-field patterns.

  3. Study of electron-beam-evaporated MgO films using electron diffraction, optical absorption and cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Aboelfotoh, M.O.; Ramsey, J.N.

    1982-05-21

    Reflection high energy electron diffraction, optical absorption and cathodoluminescence were used to study MgO films deposited onto fused silica, single-crystal silicon and LiF substrates at various temperatures. Results showed that some of the same optical absorption and emission bands observed in X- or UV-irradiated, additively colored or mechanically deformed MgO crystals were observed in evaporated MgO films. The peak positions and the relative peak intensities of the optical absorption and emission bands depended on the substrate temperature during film deposition as well as on the structure of the film. The effect of heating the films in air and vacuum on the optical absorption and emission bands is also discussed.

  4. Optical fibres in the radiation environment of CERN

    Science.gov (United States)

    Guillermain, E.

    2017-11-01

    CERN, the European Organization for Nuclear Research (in Geneva, Switzerland), is home to a complex scientific instrument: the 27-kilometre Large Hadron Collider (LHC) collides beams of high-energy particles at close to the speed of light. Optical fibres are widely used at CERN, both in surface areas (e.g. for inter-building IT networks) and in the accelerator complex underground (e.g. for cryogenics, vacuum, safety systems). Optical fibres in the accelerator are exposed to mixed radiation fields (mainly composed of protons, pions, neutrons and other hadrons, gamma rays and electrons), with dose rates depending on the particular installation zone, and with radiation levels often significantly higher than those encountered in space. In the LHC and its injector chain radiation levels range from relatively low annual doses of a few Gy up to hundreds of kGy. Optical fibres suffer from Radiation Induced Attenuation (RIA, expressed in dB per unit length) that affect light transmission and which depends on the irradiation conditions (e.g. dose rate, total dose, temperature). In the CERN accelerator complex, the failure of an optical link can affect the proper functionality of control or monitoring systems and induce the interruption of the accelerator operation. The qualification of optical fibres for installation in critical radiation areas is therefore crucial. Thus, all optical fibre types installed in radiation areas at CERN are subject to laboratory irradiation tests, in order to evaluate their RIA at different total dose and dose rates. This allows the selection of the appropriate optical fibre type (conventional or radiation resistant) compliant with the requirements of each installation. Irradiation tests are performed in collaboration with Fraunhofer INT (irradiation facilities and expert team in Euskirchen, Germany). Conventional off-the-shelf optical fibres can be installed for optical links exposed to low radiation levels (i.e. annual dose typically below few

  5. Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sidek, S. [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia); Medical Imaging Unit, Faculty of Medicine, Universiti Teknologi MARA, Selangor (Malaysia); Ramli, N. [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia); Rahmat, K., E-mail: katt_xr2000@yahoo.com [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia); Ramli, N.M.; Abdulrahman, F. [Department of Ophthalmology, Faculty of Medicine, University Malaya, Kuala Lumpur (Malaysia); Tan, L.K. [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia)

    2014-08-15

    Objectives: To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness. Methods: 3-Tesla DTI was performed on 90 subjects (30 normal, 30 mild glaucoma and 30 severe glaucoma subjects) and the FA and MD of the optic nerve and optic radiation were measured. The categorisation into mild and severe glaucoma was done using the Hodapp–Parrish–Anderson (HPA) classification. RNFL thickness was also assessed on all subjects using OCT. Receiver operating characteristic (ROC) analysis and Spearman's correlation coefficient was carried out. Results: FA and MD values in the optic nerve and optic radiation decreased and increased respectively as the disease progressed. FA at the optic nerve had the highest sensitivity (87%) and specificity (80%). FA values displayed the strongest correlation with RNFL thickness in the optic nerve (r = 0.684, p ≤ 0.001) while MD at the optic radiation showed the weakest correlation with RNFL thickness (r = −0.360, p ≤ 0.001). Conclusions: The high sensitivity and specificity of DTI-derived FA values in the optic nerve and the strong correlation between DTI-FA and RNFL thickness suggest that these parameters could serve as indicators of disease severity.

  6. Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation

    International Nuclear Information System (INIS)

    Sidek, S.; Ramli, N.; Rahmat, K.; Ramli, N.M.; Abdulrahman, F.; Tan, L.K.

    2014-01-01

    Objectives: To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness. Methods: 3-Tesla DTI was performed on 90 subjects (30 normal, 30 mild glaucoma and 30 severe glaucoma subjects) and the FA and MD of the optic nerve and optic radiation were measured. The categorisation into mild and severe glaucoma was done using the Hodapp–Parrish–Anderson (HPA) classification. RNFL thickness was also assessed on all subjects using OCT. Receiver operating characteristic (ROC) analysis and Spearman's correlation coefficient was carried out. Results: FA and MD values in the optic nerve and optic radiation decreased and increased respectively as the disease progressed. FA at the optic nerve had the highest sensitivity (87%) and specificity (80%). FA values displayed the strongest correlation with RNFL thickness in the optic nerve (r = 0.684, p ≤ 0.001) while MD at the optic radiation showed the weakest correlation with RNFL thickness (r = −0.360, p ≤ 0.001). Conclusions: The high sensitivity and specificity of DTI-derived FA values in the optic nerve and the strong correlation between DTI-FA and RNFL thickness suggest that these parameters could serve as indicators of disease severity

  7. Spectral and kinetic analysis of radiation induced optical attenuation in silica: towards intrinsic fibre optic dosimetry?

    International Nuclear Information System (INIS)

    Borgermans, P.

    2002-01-01

    The document is an abstract of a PhD thesis. The PhD work concerns the detailed investigation of the behaviour of optical fibres in radiation fields such as is the case for various nuclear and space application,s. The core of the work concerns the spectral and kinetic analysis of the radiation induced optical attenuation. Models describing underlying physical phenomena, both for the spectral and the time dimensions, have been developed. The potential of silica optical fibre waveguides for intrinsic dosimetry has been assessed by employing specific properties of radiation induced defects in the silica waveguide material

  8. Near-diffraction-limited and low-haze electro-optical tunable liquid crystal lens with floating electrodes.

    Science.gov (United States)

    Li, Liwei; Bryant, Doug; Van Heugten, Tony; Bos, Philip J

    2013-04-08

    A near-diffraction-limited, low-haze and tunable liquid crystal (LC) lens is presented. Building on an understanding of the key factors that have limited the performance of lenses based on liquid crystals, we show a simple design whose optical quality is similar to a high quality glass lens. It uses 'floating' electrodes to provide a smooth, controllable applied potential profile across the aperture to manage the phase profile.

  9. Measurement of radiation damage on an optical reflector

    International Nuclear Information System (INIS)

    Peng, K.C.; Sahu, S.K.; Huang, H.C.; Ueno, K.; Chang, Y.H.; Wang, C.H.; Hou, W.S.

    1997-01-01

    We measured the radiation damage on an optical white fluorocarbon reflector called Goretex, which is to be used for aerogel threshold counters and crystal calorimeters of the BELLE detector of the KEK B-factory. Reflectance of the Goretex surface was monitored to see any effect of the radiation damage. Maximum equivalent dose was 8.6 Mrad. No radiation damage is observed within measurement errors. (orig.)

  10. Design of high-efficiency diffractive optical elements towards ultrafast mid-infrared time-stretched imaging and spectroscopy

    Science.gov (United States)

    Xie, Hongbo; Ren, Delun; Wang, Chao; Mao, Chensheng; Yang, Lei

    2018-02-01

    Ultrafast time stretch imaging offers unprecedented imaging speed and enables new discoveries in scientific research and engineering. One challenge in exploiting time stretch imaging in mid-infrared is the lack of high-quality diffractive optical elements (DOEs), which encode the image information into mid-infrared optical spectrum. This work reports the design and optimization of mid-infrared DOE with high diffraction-efficiency, broad bandwidth and large field of view. Using various typical materials with their refractive indices ranging from 1.32 to 4.06 in ? mid-infrared band, diffraction efficiencies of single-layer and double-layer DOEs have been studied in different wavelength bands with different field of views. More importantly, by replacing the air gap of double-layer DOE with carefully selected optical materials, one optimized ? triple-layer DOE, with efficiency higher than 95% in the whole ? mid-infrared window and field of view greater than ?, is designed and analyzed. This new DOE device holds great potential in ultrafast mid-infrared time stretch imaging and spectroscopy.

  11. Parametric X-rays and diffracted transition radiation in perfect and mosaic crystals

    International Nuclear Information System (INIS)

    Artru, X.; Rullhusen, P.

    1998-01-01

    The amplitude of X-ray emission by relativistic electrons in a single crystal, calculated in the kinematical approach, is decomposed unambiguously in Diffracted Transition Radiation (DTR) and Parametric X-rays (PXR). DTR becomes significant for γ > or similar to ω P ,γ being the Lorentz factor and ω P the plasma frequency. It is more collimated than PXR and, above threshold, its flux increases logarithmically with γ. However, it saturates with thickness at the Bragg primary extinction length l e . This saturation is accounted for only in the dynamical approach, the formulas of which are compared to the kinematical ones. The respective contributions of DTR and PXR are calculated for a simple model of mosaic crystal, taking into account saturation of DTR with thickness. The PXR flux is basically the same as in a perfect crystal. If the size of the domains is larger than l e , the DTR flux is multiplied by the number of domains crossed by the electron. For domains smaller than l e and γ > or similar to ω P , the DTR and PXR fluxes are of the same order of magnitude, up to logarithmic factors. In any case, mosaicity increases the total yield of X-ray photons. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Classification of lead white pigments using synchrotron radiation micro X-ray diffraction

    International Nuclear Information System (INIS)

    Welcomme, E.; Walter, P.; Menu, M.; Bleuet, P.; Hodeau, J.L.; Dooryhee, E.; Martinetto, P.

    2007-01-01

    Lead white pigment was used and synthesised for cosmetic and artistic purposes since the antiquity. Ancient texts describe the various recipes, and preparation processes as well as locations of production. In this study, we describe the results achieved on several paint samples taken from Matthias Gruenewald's works. Gruenewald, who was active between 1503 and 1524, was a major painter at the beginning of the German Renaissance. Thanks to X-ray diffraction analysis using synchrotron radiation, it is possible to associate the composition of the paint samples with the masters ancient recipes. Different approaches were used, in reflection and transmission modes, directly on minute samples or on paint cross-sections embedded in resin. Characterisation of lead white pigments reveals variations in terms of composition, graininess and proportion of mineral phases. The present work enlightens the presence of lead white as differentiable main composition groups, which could be specific of a period, a know-how or a geographical origin. In this way, we aim at understanding the choices and the trading of pigments used to realise paintings during northern European Renaissance. (orig.)

  13. Classification of lead white pigments using synchrotron radiation micro X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Welcomme, E.; Walter, P.; Menu, M. [Centre de Recherche et de Restauration des Musees de France - CNRS UMR 171, Paris (France); Bleuet, P. [European Synchrotron Radiation Facility, BP 220, Grenoble Cedex (France); Hodeau, J.L.; Dooryhee, E.; Martinetto, P. [Institut Neel CNRS-UPR 503-1, 25, Av. des Martyrs, BP 166, Grenoble Cedex 9 (France)

    2007-12-15

    Lead white pigment was used and synthesised for cosmetic and artistic purposes since the antiquity. Ancient texts describe the various recipes, and preparation processes as well as locations of production. In this study, we describe the results achieved on several paint samples taken from Matthias Gruenewald's works. Gruenewald, who was active between 1503 and 1524, was a major painter at the beginning of the German Renaissance. Thanks to X-ray diffraction analysis using synchrotron radiation, it is possible to associate the composition of the paint samples with the masters ancient recipes. Different approaches were used, in reflection and transmission modes, directly on minute samples or on paint cross-sections embedded in resin. Characterisation of lead white pigments reveals variations in terms of composition, graininess and proportion of mineral phases. The present work enlightens the presence of lead white as differentiable main composition groups, which could be specific of a period, a know-how or a geographical origin. In this way, we aim at understanding the choices and the trading of pigments used to realise paintings during northern European Renaissance. (orig.)

  14. Integration of optical fibers in radiative environments: Advantages and limitations

    International Nuclear Information System (INIS)

    Girard, S.; Ouerdane, Y.; Boukenter, A.; Marcandella, C.; Bisutti, J.; Baggio, J.; Meunier, J. P.

    2011-01-01

    We review the advantages and limitations for the integration of optical fibers in radiative environments. Optical fibers present numerous advantages for applications in harsh environments such as their electromagnetic immunity. This explains the increasing interest of the radiation effects community to evaluate their vulnerability for future facilities. However, it is also well-known that optical fibers suffer from a degradation of their macroscopic properties under irradiation. We illustrate the major mechanisms and parameters that govern the degradation mechanism, mainly the radiation-induced attenuation phenomena. We focus on the fiber transient radiation responses when exposed to the pulsed and mixed environment associated with the Megajoule class lasers devoted to the fusion by inertial confinement study. (authors)

  15. Diffusion tensor imaging of occult injury of optic radiation following optic neuritis in multiple sclerosis.

    Science.gov (United States)

    Chen, Jiafeng; Zhu, Lijun; Li, He; Lu, Ziwen; Chen, Xin; Fang, Shaokuan

    2016-10-01

    Multiple sclerosis (MS) is easily detected by routine magnetic resonance imaging (MRI). However, it is not possible to detect early or occult lesions in MS by routine MRI, and this may explain the inconsistency between the severity of the lesions found by MRI and the degree of clinical disability of patients with MS. The present study included 10 patients with relapsing-remitting MS and 10 healthy volunteers. Each patient underwent routine 3.0 T MRI, diffusion tensor imaging (DTI), and diffusion tensor tractography (DTT). Optic nerve and optic radiation were analyzed by DTI and DTT. The fractional anisotropy (FA), mean diffusivity (MD), λ // , and λ ┴ values were measured. In the 10 patients with MS, 7 optic nerves were affected, and 13 optic nerves were not affected. Cranial MRI showed that optic nerve thickening and hyperintensity occurred in 2 patients with MS. In the directionally encoded color maps, a hypointensive green signal in the optic nerve was observed in 3 patients with MS. The FA values were significantly lower and the MD, λ // , and λ ┴ values were significantly higher in the affected and unaffected optic nerves and optic radiations in patients with MS in comparison with controls (P0.05). Diffusion tensor imaging is sensitive in the detection of occult injury of the optic nerve and optic radiation following optic neuritis. Diffusion tensor imaging may be a useful tool for the early diagnosis, treatment and management of MS.

  16. Optical systems for synchrotron radiation. Lecture 1. Introductory topics. Revision

    International Nuclear Information System (INIS)

    Howells, M.R.

    1986-02-01

    Various fundamental topics are considered which underlie the design and use of optical systems for synchrotron radiation. The point of view of linear system theory is chosen which acts as a unifying concept throughout the series. In this context the important optical quantities usually appear as either impulse response functions (Green's functions) or frequency transfer functions (Fourier Transforms of the Green's functions). Topics include the damped harmonic oscillator, free-space optical field propagation, optical properties of materials, dispersion, and the Kramers-Kronig relations

  17. Performance of an optical encoder based on a nondiffractive beam implemented with a specific photodetection integrated circuit and a diffractive optical element.

    Science.gov (United States)

    Quintián, Fernando Perez; Calarco, Nicolás; Lutenberg, Ariel; Lipovetzky, José

    2015-09-01

    In this paper, we study the incremental signal produced by an optical encoder based on a nondiffractive beam (NDB). The NDB is generated by means of a diffractive optical element (DOE). The detection system is composed by an application specific integrated circuit (ASIC) sensor. The sensor consists of an array of eight concentric annular photodiodes, each one provided with a programmable gain amplifier. In this way, the system is able to synthesize a nonuniform detectivity. The contrast, amplitude, and harmonic content of the sinusoidal output signal are analyzed. The influence of the cross talk among the annular photodiodes is placed in evidence through the dependence of the signal contrast on the wavelength.

  18. Optical fiber composition and radiation hardness

    International Nuclear Information System (INIS)

    Wall, J.A.; Loretz, T.J.

    1982-01-01

    Germanium phosphosilicate and germanium borosilicate fibers doped with cerium were fabricated and tested for their responses to steady-state Co-60 radiation at -55 C, +20 C and +125 C. A fiber with germanium, boron and phosphorous in the silicate core and doped with antimony in the core and clad was similarly tested. All of the fibers showed significant improvements in radiation hardness at 20 C compared to undoped fibers of the same base composition. At -55 C, however, all except the cerium doped germanium phosphosilicate were very radiation sensitive and also showed increases in the rate of induced loss at +125 C. The cerium doped germanium phosphosilicate fiber showed virtually no change in radiation sensitivity at the temperature extremes and could prove useful in applications requiring relatively short lengths of fiber

  19. Versatile digital micromirror device-based method for the recording of multilevel optical diffractive elements in photosensitive chalcogenide layers (AMTIR-1).

    Science.gov (United States)

    Joerg, Alexandre; Vignaux, Mael; Lumeau, Julien

    2016-08-01

    A new alternative and versatile method for the production of diffractive optical elements (DOEs) with up to four phase levels in AMTIR-1 (Ge33As12Se55) layers is demonstrated. The developed method proposes the use of the photosensitive properties of the layers and a specific in situ optical monitoring coupled with a reverse engineering algorithm to control the trigger points of the writing of the different diffractive patterns. Examples of various volume DOEs are presented.

  20. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J.

    1991-01-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain

  1. Optical Effects Accompanying the Dynamical Bragg Diffraction in Linear 1D Photonic Crystals Based on Porous Silicon

    Directory of Open Access Journals (Sweden)

    Anton Maydykovskiy

    2014-10-01

    Full Text Available We survey our recent results on the observation and studies of the effects accompanying the dynamical Bragg diffraction in one-dimensional photonic crystals (PhC. Contrary to the kinematic Bragg diffraction, the dynamical one considers a continuous interaction between the waves travelling within a spatially-periodic structure and is the most pronounced in the so called Laue geometry, leading to a number of exciting phenomena. In the described experiments, we study the PhC based on porous silicon or porous quartz, made by the electrochemical etching of crystalline silicon with the consequent thermal annealing. Importantly, these PhC are approximately hundreds of microns thick and contain a few hundreds of periods, so that the experiments in the Laue diffraction scheme are available. We discuss the effect of the temporal splitting of femtosecond laser pulses and show that the effect is quite sensitive to the polarization and the phase of a femtosecond laser pulse. We also show the experimental realization of the Pendular effect in porous quartz PhC and demonstrate the experimental conditions for the total spatial switching of the output radiation between the transmitted and diffracted directions. All described effects are of high interest for the control over the light propagation based on PhC structures.

  2. Radiation damage in commercial optical fibers

    International Nuclear Information System (INIS)

    Bertolotti, M.; Franceschini, F.A.; Serra, A.

    1978-01-01

    Experimental results obtained by exposure of commercial optical fibers to 60 Co γ-ray irradiation, are reported. The possibility of utilizing these fibers as far as a total dose of 6000 rad in the light spectrum is shown. It is also shown that it is possible to obtain total recovery of irradiated fibers by annealing at 500 0 C. (author)

  3. Initial idea to use optical flats for x-ray fluorescence analysis and recent applications to diffraction studies

    International Nuclear Information System (INIS)

    Horiuchi, T.

    1993-01-01

    Described in this work is the initial idea of using an optical flat for X-ray fluorescence analysis based upon studies of anomalous surface reflection (ASR). To develop total-reflection X-ray fluorescence analysis (TXRF) as one of the most powerful tools for microchemical analysis, various experiments such as the micro-determinations of uranium in sea-water, iron in human blood and rare earth elements in hot spring-water were attempted. Furthermore, the physically interesting experiment on Compton scattering under total-reflection conditions was conducted. Recent applications of the total-reflection phenomenon to diffraction studies, i.e. total-reflection X-ray diffraction (TXRD), are also presented. (author)

  4. Diffraction-limited real-time terahertz imaging by optical frequency up-conversion in a DAST crystal.

    Science.gov (United States)

    Fan, Shuzhen; Qi, Feng; Notake, Takashi; Nawata, Kouji; Takida, Yuma; Matsukawa, Takeshi; Minamide, Hiroaki

    2015-03-23

    Real-time terahertz (THz) wave imaging has wide applications in areas such as security, industry, biology, medicine, pharmacy, and the arts. This report describes real-time room-temperature THz imaging by nonlinear optical frequency up-conversion in an organic 4-dimethylamino-N'-methyl-4'-stilbazolium tosylate (DAST) crystal, with high resolution reaching the diffraction limit. THz-wave images were converted to the near infrared region and then captured using an InGaAs camera in a tandem imaging system. The resolution of the imaging system was analyzed. Diffraction and interference of THz wave were observed in the experiments. Videos are supplied to show the interference pattern variation that occurs with sample moving and tilting.

  5. Full-color, large area, transmissive holograms enabled by multi-level diffractive optics.

    Science.gov (United States)

    Mohammad, Nabil; Meem, Monjurul; Wan, Xiaowen; Menon, Rajesh

    2017-07-19

    We show that multi-level diffractive microstructures can enable broadband, on-axis transmissive holograms that can project complex full-color images, which are invariant to viewing angle. Compared to alternatives like metaholograms, diffractive holograms utilize much larger minimum features (>10 µm), much smaller aspect ratios (30 mm ×30 mm). We designed, fabricated and characterized holograms that encode various full-color images. Our devices demonstrate absolute transmission efficiencies of >86% across the visible spectrum from 405 nm to 633 nm (peak value of about 92%), and excellent color fidelity. Furthermore, these devices do not exhibit polarization dependence. Finally, we emphasize that our devices exhibit negligible absorption and are phase-only holograms with high diffraction efficiency.

  6. Thermal behaviour of molecular sieves (SAPO-11/AIPO-11 type) investigated by synchrotron radiation X-ray diffraction (SRXD)

    International Nuclear Information System (INIS)

    Neissendorfer, F.; Jahn, E.; Gusenko, S.N.; Sheromov, M.A.

    1991-01-01

    The structure of molecular sieves is important for a successful application as a catalyzer. The final structure of the synthetic product depends on the technological steps. This process was investigated by in-situ Synchrotron radiation X-ray diffraction. Structural changes in the molecular sieves exist not only during the heating process but also during the following cooling process. (author) 3 figs., 2 refs

  7. High-pressure X-ray diffraction studies on ThS up to 40 GPa using synchrotron radiation

    International Nuclear Information System (INIS)

    Benedict, U.; Spirlet, J.C.; Gerward, L.; Olsen, J.S.

    1983-12-01

    High-pressure X-ray diffraction studies have been performed on ThS up to 40 GPa using synchrotron radiation and a diamond anvil cell. The measured value of the bulk modulus B 0 =145 GPa is in disagreement with a previous measurement. The high-pressure behaviour indicates a phase transformation to ThS II starting at 15 to 20 GPa. The transformation is of second order nature, the resulting structure can be described as distorted fcc. (orig.)

  8. High pressure X-ray diffraction studies on ThS up to 40 GPa using synchrotron radiation

    International Nuclear Information System (INIS)

    Benedict, U.; Spirlet, J.C.; Gerward, L.; Olsen, J.S.

    1984-01-01

    High pressure X-ray diffraction studies (up to 40 GPa) were performed on ThS using synchrotron radiation and a diamond anvil cell. The measured value of 145 GPa for the bulk modulus B 0 disagrees with a previous measurement. The high pressure behaviour indicates a phase transformation to ThS II starting at 15 - 20 GPa. The transformation is of the second-order type, and the resulting structure can be described as distorted f.c.c. (Auth.)

  9. Convenient models of the atmosphere: optics and solar radiation

    Science.gov (United States)

    Alexander, Ginsburg; Victor, Frolkis; Irina, Melnikova; Sergey, Novikov; Dmitriy, Samulenkov; Maxim, Sapunov

    2017-11-01

    Simple optical models of clear and cloudy atmosphere are proposed. Four versions of atmospheric aerosols content are considered: a complete lack of aerosols in the atmosphere, low background concentration (500 cm-3), high concentrations (2000 cm-3) and very high content of particles (5000 cm-3). In a cloud scenario, the model of external mixture is assumed. The values of optical thickness and single scattering albedo for 13 wavelengths are calculated in the short wavelength range of 0.28-0.90 µm, with regard to the molecular absorption bands, that is simulated with triangle function. A comparison of the proposed optical parameters with results of various measurements and retrieval (lidar measurement, sampling, processing radiation measurements) is presented. For a cloudy atmosphere models of single-layer and two-layer atmosphere are proposed. It is found that cloud optical parameters with assuming the "external mixture" agrees with retrieved values from airborne observations. The results of calculating hemispherical fluxes of the reflected and transmitted solar radiation and the radiative divergence are obtained with the Delta-Eddington approach. The calculation is done for surface albedo values of 0, 0.5, 0.9 and for spectral values of the sandy surface. Four values of solar zenith angle: 0°, 30°, 40° and 60° are taken. The obtained values are compared with data of radiative airborne observations. Estimating the local instantaneous radiative forcing of atmospheric aerosols and clouds for considered models is presented together with the heating rate.

  10. PiC code KARAT simulations of Coherent THz Smith-Purcell Radiation from diffraction gratings of various profiles

    International Nuclear Information System (INIS)

    Artyomov, K P; Ryzhov, V V; Potylitsyn, A P; Sukhikh, L G

    2017-01-01

    Generation of coherent THz Smith-Purcell radiation by single electron bunch or multi-bunched electron beam was simulated for lamellar, sinusoidal and echelette gratings. The dependences of the CSPR intensity of the corrugation gratings depth were investigated. The angular and spectral characteristics of the CSPR for different profiles of diffraction gratings were obtained. It is shown that in the case of femtosecond multi-bunched electron beam with 10 MeV energy sinusoidal grating with period 292 μm and groove depth 60 μm has the uniform angular distribution with high radiation intensity. (paper)

  11. Heavy irradiation effects in radiation-resistant optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Shikama, Tatsuo [Tohoku Univ., Oarai, Ibaraki (Japan). Oarai Branch, Inst. for Materials Research

    1998-07-01

    Development of a system for optical measurements in a nuclear reactor has been progressing to investigate dynamic changes in a material caused by heavy irradiation. In such system, transfer of optical signals to out-pile measuring systems is being attempted by the use of optical fibers. In this report, the characteristics of optical fibers in the heavy irradiation field were summarized. It has been known that amorphous silica might produce radiolysis and structural defects by the exposure to ionizing radiation. The effects of heavy irradiation on molten silica were extremely complicated. A large intensity of visible light absorption occurred from an early time during start-up of the reactor. The absorption range was limited below 700 nm for the radiation associating fast neutron and the absorption was mostly attributed to non-bridging oxygen hole center. The depletion of optical transferring capacity under the radiation might be related to the internal stress. Therefore, it seems desirable to use optical fibers in the conditions without leading too much stress. (M.N.)

  12. Geometrical characterization of micro-optical cylindrical lens arrays using angular resolved diffraction

    DEFF Research Database (Denmark)

    Iversen, Theis Faber Quist; Hanson, Steen Grüner

    2010-01-01

    been shown (Iversen et al 2009 J. Opt. A: Pure Appl. Opt. 11 054014 (6pp), B¨uttner and Zeitner 2002 Appl. Opt. 41 6841 8) that the average radius of curvature of an MLA structure can be extracted by observing the far-field diffraction pattern intensity distribution obtained from illumination....... By scanning the angle of incidence of the coherent illumination and simultaneously observing the diffracted intensity, information about the grating period and the radius of curvature can be extracted. The method is implemented with emphasis on further development for compact, high-speed dedicated systems. We...

  13. Radiation hardness of new Kuraray double cladded optical fibers

    International Nuclear Information System (INIS)

    Bedeschi, F.; Menzione, A.; Budagov, Yu.; Chirikov-Zorin, I.; Solov'ev, A.; Turchanovich, L.; Vasil'chenko, V.

    1996-01-01

    The radiation hardness of the new plastic scintillating and clear fibers irradiated by 137 Cs γ-flux and by pulsed reactor fast neutrons were investigated. All the studied fibers were of S-type (with S=70) and had a double cladding. Optical fibers degradation study after irradiation shows that the level of radiation hardness lower that what is expected from results of previous studies. 9 refs., 6 figs

  14. Radiation Effects on Ytterbium-doped Optical Fibers

    Science.gov (United States)

    2014-06-02

    conducted on Er- doped fiber amplifiers (Lezius, et al., 2012; Ahrens, et al., 1999; Ahrens, Jaques , LuValle, DiGiovanni, & Windeler, 2001; Ott, 2004...Ahrens, R. G., Abate, J. A., Jaques , J. J., Presby, H. M., Fields, A. B., DiGiovanni, D. J., LuValle, M. J. (1999). Radiation reliability of rare... Jaques , J. J., LuValle, M. J., DiGiovanni, D. J., & Windeler, R. S. (2001). Radiation effects on optical fibers and amplifiers. Testing, Reliability

  15. Effects of angular misalignment on optical klystron undulator radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, G., E-mail: gmishra_dauniv@yahoo.co.in; Prakash, Bramh; Gehlot, Mona

    2015-11-21

    In this paper ,we analyze the important effects of optical klystron undulator radiation with an angular offset of the relativistic electron beam in the second undulator section. An anlytical expression for the undulator radiation is obtained through a transparent and simple procedure.It is shown that the effects of the angular offset is more severe for longer undulator lengths and with higher dispersive field strengths.Both these effects are less pronounced for undulators with large K values.

  16. Optical forces induced behavior of a particle in a non-diffracting vortex beam

    Czech Academy of Sciences Publication Activity Database

    Šiler, Martin; Jákl, Petr; Brzobohatý, Oto; Zemánek, Pavel

    2012-01-01

    Roč. 20, č. 22 (2012), s. 24304-24319 ISSN 1094-4087 R&D Projects: GA ČR GPP205/11/P294; GA MŠk ED0017/01/01; GA MŠk LH12018 Institutional support: RVO:68081731 Keywords : optical vortex beam * tweezers * optical forces Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.546, year: 2012

  17. Basic study on radiation distribution sensing with normal optical fiber

    International Nuclear Information System (INIS)

    Naka, R.; Kawarabayashi, J.; Uritani, A.; Iguchi, T.; Kaneko, J.; Takeuchi, H.; Kakuta, T.

    2000-01-01

    Recently, some methods of radiation distribution sensing with optical fibers have been proposed. These methods employ scintillating fibers or scintillators with wavelength-shifting fibers. The positions of radiation interactions are detected by applying a time-of-flight (TOF) technique to the scintillation photon propagation. In the former method, the attenuation length for the scintillation photons in the scintillating fiber is relatively short, so that the operating length of the sensor is limited to several meters. In the latter method, a radiation distribution cannot continuously be obtained but discretely. To improve these shortcomings, a normal optical fiber made of polymethyl methacrylate (PMMA) is used in this study. Although the scintillation efficiency of PMMA is very low, several photons are emitted through interaction with a radiation. The fiber is transparent for the emitted photons to have a relatively long operating length. A radiation distribution can continuously be obtained. This paper describes a principle of the position sensing method based on the time of flight technique and preliminary results obtained for 90 Sr- 90 Y beta rays, 137 Cs gamma rays, and 14 MeV neutrons. The spatial resolutions for the above three kinds of radiations are 0.30 m, 0.37 m, 0.13 m, and the detection efficiencies are 1.1 x 10 -3 , 1.6 x 10 -7 , 5.4 x 10 -6 , respectively, with 10 m operation length. The results of a spectroscopic study on the optical property of the fiber are also described. (author)

  18. Study of optical radiation from SiO2 during reactor irradiation

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Narui, Minoru; Kakuta, Tsunemi; Kayano, Hideo; Sagawa, Tsutomu; Sanada, Kazuo

    1994-01-01

    Optical radiations were observed from optical fibers under irradiation in a fission reactor, JMTR. A major part of the observed optical radiations is thought to be composed of broad optical radiation in the whole wavelength range studied in the present experiment. This broad optical radiation will be generated by the process of so-called Cherenkov radiation. Also, a sharp optical radiation peak was found at 1270 nm on a F-doped fiber. This peak is thought to relate with doped fluorine ions and ionizing gamma-ray irradiation. ((orig.))

  19. Anomalous effect of high-frequency ultrasound on radiation diffraction in deformed single crystals

    International Nuclear Information System (INIS)

    Iolin, E.M.; Rajtman, Eh.A.; Kuvaldin, B.V.; Zolotoyabko, Eh.V.

    1988-01-01

    Results are presented of a theoretical and experimental study of neutron and X-ray diffraction in defromed single crystals on high-frequency ultrasonic excitation. It is demonstrated theoretically that at a frequency exceeding a certain threshold value the ultrasound violates the adiabatic conditions for the excitation point motion on the dispersion surface branches. This leads to an anomalous (compared to diffraction for a perfect crystal) dependence of the diffraction intensity on the ultrasonic wave amplitude. The experimental data for Si crystals are in good agreement with the theoretical predictions

  20. Radiation-hard/high-speed parallel optical links

    Energy Technology Data Exchange (ETDEWEB)

    Gan, K.K., E-mail: gan@mps.ohio-state.edu [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Buchholz, P.; Heidbrink, S. [Fachbereich Physik, Universität Siegen, Siegen (Germany); Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S. [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Vogt, M.; Ziolkowski, M. [Fachbereich Physik, Universität Siegen, Siegen (Germany)

    2016-09-21

    We have designed and fabricated a compact parallel optical engine for transmitting data at 5 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The performance of the optical engine up at 5 Gb/s is satisfactory.

  1. System of laser pump and synchrotron radiation probe microdiffraction to investigate optical recording process

    International Nuclear Information System (INIS)

    Yasuda, Nobuhiro; Fukuyama, Yoshimitsu; Osawa, Hitoshi; Kimura, Shigeru; Ito, Kiminori; Tanaka, Yoshihito; Matsunaga, Toshiyuki; Kojima, Rie; Hisada, Kazuya; Tsuchino, Akio; Birukawa, Masahiro; Yamada, Noboru; Sekiguchi, Koji; Fujiie, Kazuhiko; Kawakubo, Osamu; Takata, Masaki

    2013-01-01

    We have developed a system of laser-pump and synchrotron radiation probe microdiffraction to investigate the phase-change process on a nanosecond time scale of Ge 2 Sb 2 Te 5 film embedded in multi-layer structures, which corresponds to real optical recording media. The measurements were achieved by combining (i) the pump-laser system with a pulse width of 300 ps, (ii) a highly brilliant focused microbeam with wide peak-energy width (ΔE/E ∼ 2%) made by focusing helical undulator radiation without monochromatization, and (iii) a precise sample rotation stage to make repetitive measurements. We successfully detected a very weak time-resolved diffraction signal by using this system from 100-nm-thick Ge 2 Sb 2 Te 5 phase-change layers. This enabled us to find the dependence of the crystal-amorphous phase change process of the Ge 2 Sb 2 Te 5 layers on laser power.

  2. Rotating and standing waves in a diffractive nonlinear optical system with delayed feedback under O(2) Hopf bifurcation

    Science.gov (United States)

    Budzinskiy, S. S.; Razgulin, A. V.

    2017-08-01

    In this paper we study one-dimensional rotating and standing waves in a model of an O(2)-symmetric nonlinear optical system with diffraction and delay in the feedback loop whose dynamics is governed by a system of coupled delayed parabolic equation and linear Schrodinger-type equation. We elaborate a two-step approach: transition to a rotating coordinate system to obtain the profiles of the waves as small parameter expansions and the normal form technique to study their qualitative dynamic behavior and stability. Theoretical results stand in a good agreement with direct computer simulations presented.

  3. Diffractive-optics-based sensor as a tool for detection of biocompatibility of titanium and titanium-doped hydrocarbon samples

    Czech Academy of Sciences Publication Activity Database

    Silvennoinen, R.; Hasoň, Stanislav; Vetterl, Vladimír; Penttinen, N.; Silvennoinen, M.; Myller, K.; Černochová, P.; Bartáková, S.; Prachár, P.; Cvrček, L.

    2010-01-01

    Roč. 49, č. 29 (2010), s. 5583-5591 ISSN 0003-6935 R&D Projects: GA AV ČR(CZ) KAN200040651; GA ČR(CZ) GA202/08/1688; GA ČR(CZ) GAP205/10/2378 Grant - others:GA MŠk(CZ) 1M0528 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : fibrinogen adsorption * titanium dental implants * diffractive optical element Subject RIV: BO - Biophysics Impact factor: 1.703, year: 2010

  4. Diffractive optics for reduction of hot cracking in pulsed mode Nd:YAG laser welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Olesen, Søren; Roos, Sven-Olov

    2001-01-01

    In order to reduce the susceptibility to hot cracking in pulsed mode laser welding of austenitic stainless steel, an optical system for reduction of the cooling rate is sought developed. Based on intensive numerical simulations, an optical system producing three focused spots is made. In a number...

  5. Effects of diffraction and target finite size on coherent transition radiation spectra in bunch length measurements

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, M.; Cianchi, A.; Verzilov, V.A. [Istituto Nazionale di Fisica Nucleare, Frascati, RM (Italy). Laboratori Nazionali di Frascati; Orlandi, G. [Istituto Nazionale di Fisica Nucleare, Rome (Italy)]|[Rome Univ., Tor Vergata, Rome (Italy)

    1999-07-01

    Effects of diffraction and the size of the target on TR in the context of CTR-based bunch length measurements are studied on the basis of Kirchhoff diffraction theory. Spectra of TR from the finite-size target for several schemes of measurements are calculated in the far-infrared region showing strong distortion at low frequencies. Influence of the effect on the accuracy of bunch length measurements is estimated.

  6. Optical systems for synchrotron radiation. Lecture 2. Mirror systems

    International Nuclear Information System (INIS)

    Howells, M.R.

    1986-02-01

    The process of reflection of VUV and x-radiation is summarized. The functions of mirrors in synchrotron beamlines are described, which include deflection, filtration, power absorption, formation of a real image, focusing, and collimation. Fabrication of optical surfaces for synchrotron radiation beamlines are described, and include polishing of a near spherical surface as well as bending a cylindrical surface to toroidal shape. The imperfections present in mirrors, aberrations and surface figure inaccuracy, are discussed. Calculation of the thermal load of a mirror in a synchrotron radiation beam and the cooling of the mirror are covered briefly. 50 refs., 7 figs

  7. BOOK REVIEW: Analysis of Residual Stress by Diffraction Using Neutron and Synchrotron Radiation

    Science.gov (United States)

    Fitzpatrick, ed M. E.; Lodini, A.

    2003-09-01

    The presence of residual stresses within engineering components is often a key feature in determining their usable lifetimes and failure characteristics. Residual surface compression can, for example, restrict the propagation of surface cracks through the bulk. As a consequence, it is essential to characterize the magnitude and spatial distribution of residual stresses and, at least for non-destructive testing, this is most widely achieved using diffraction of neutron and high energy synchrotron radiations. This book aims to provide a detailed description of the methodology used to determine residual stresses. The major emphasis is placed on the neutron method, this being the more widely established approach at present. It contains 20 chapters contributed by 23 authors, divided into five major parts. The overall layout is very logical, with the first part giving a general introduction to the use of neutrons and x-rays for materials research and summarizing the methods used for their production. Part 2 considers the more specific aspects of extracting the residual stress distribution within a bulk sample and includes some valuable comments on a number of potential experimental problems, such as the determination of the stress-free lattice parameter and the effects of broadening of the Bragg peaks. The experimental facilities currently available or under development are described in part 3, with the remaining two parts devoted to general and specific applications of the residual stress measurement technique. As expected with such a large number of different authors, there is some variation in style and quality. However, the text is generally easy to follow and, more importantly, it is largely free of the problems of inconsistent notation and dupication of material that can afflict multi-authored texts. My only negative comment concerns the latter portion of the book devoted to specific applications of the technique, which is illustrative rather than comprehensive. In

  8. Survey Talk--New Laser and Optical Radiation Diagnostics

    International Nuclear Information System (INIS)

    Leemans, W.P.

    1998-01-01

    New techniques am reported for electron beam monitoring, that rely either on the analysis of the properties of wiggler radiation (from static magnetic fields as well as from laser ''undulators'', also referred to as Thomson scattering) or on the non-linear mixing of laser radiation with electron beam radiation. The different techniques reviewed are capable of providing information on femtosecond time scales and micron or even sub-micron spatial scales. The laser undulator is also proposed as a useful tool for non- destructive measurement of high power electron beams. An example is given of measuring electron beam energy and energy spread through spectral filtering of spontaneous wiggler radiation [1]. A novel technique based on fluctuational characteristics of radiation is described, for single shot, nondestructive measurement of the electron beam bunch length [2,3]. Thomson scattering based beam monitoring techniques are discussed which, through analysis of the radiated beam properties, allow non-destructive detailed measurement of transverse and longitudinal distributions of relativistic electron beams [4]. Two new techniques are discussed which rely on non-linear optical mixing of laser radiation with electron bunch emission: differential optical gating (DOG) [5] and electron bunch length measurement in a storage ring based on sum-frequency generation [6

  9. Fiber-optic multipoint radiation sensing system using waveguide scintillators

    International Nuclear Information System (INIS)

    Maekawa, Tatsuyuki; Yoda, Masaki; Tanaka, Koutarou; Masumaru, Tarou; Morimoto, Souichirou.

    1996-01-01

    Novel fiber-optic radiation sensors and a multipoint measurement method that takes advantage of them have been developed. The new sensor design, which we call a 'waveguide scintillator', consists of a scintillating material and a wavelength-shifting fiber (WLSF). The WLSF is embedded in the scintillating material, and each end is connected to a transparent optical fiber. These waveguide scintillators can be connected in series along an optical fiber loop to form a radiation monitoring system, and each end of the fiber loop is terminated with a photodetector. This new radiation monitoring arrangement dispenses with the need for electronic apparatus at each measuring point and consequently improves resistance to noise. Furthermore, it offers the advantages of multipoint monitoring - meaning that radiation intensity can be measured at multiple sensors - using only two photodetectors. We have examined the light output characteristics and time resolution of a prototype arrangement of these new waveguide scintillators, thus confirming the feasibility of multipoint measurements using a system of multiple waveguide scintillators connected in series in an optical fiber loop. (author)

  10. Atomic, molecular, and optical physics electromagnetic radiation

    CERN Document Server

    Dunning, F B; Lucatorto, Thomas

    1997-01-01

    Combined with Volumes 29A and 29B, this volume is a comprehensive treatment of the key experimental methods of atomic, molecular, and optical physics, as well as an excellent experimental handbook for the field. Thewide availability of tunable lasers in the past several years has revolutionized the field and lead to the introduction of many new experimental methods that are covered in these volumes. Traditional methods are also included to ensure that the volumes will be a complete reference source for the field.

  11. Electron cascades in sensors for optical detection of ionizing radiation

    International Nuclear Information System (INIS)

    London, Richard A.; Lowry, Mark E.; Vernon, Stephen P.; Stewart, Richard E.

    2013-01-01

    A new class of high-speed detectors, called RadOptic detectors, measures ionizing radiation incident on a transparent semiconductor by sensing changes in the refractive index with an optical probe beam. We describe the role of radiation-initiated electron cascades in setting the sensitivity and the spatial and temporal resolution of RadOptic detectors. We model electron cascades with both analytical and Monte Carlo computational methods. We find that the timescale for the development of an electron cascade is less than of order 100 fs and is not expected to affect the time response of a detector. The characteristic size of the electron cloud is typically less than 2 μm, enabling high spatial resolution in imaging systems. The electron-hole pair density created by single x-rays is much smaller than the saturation density and, therefore, single events should not saturate the detector

  12. Synchrotron Bragg diffraction imaging characterization of synthetic diamond crystals for optical and electronic power device applications1 1

    Science.gov (United States)

    Tran Thi, Thu Nhi; Morse, J.; Caliste, D.; Fernandez, B.; Eon, D.; Härtwig, J.; Mer-Calfati, C.; Tranchant, N.; Arnault, J. C.; Lafford, T. A.; Baruchel, J.

    2017-01-01

    Bragg diffraction imaging enables the quality of synthetic single-crystal diamond substrates and their overgrown, mostly doped, diamond layers to be characterized. This is very important for improving diamond-based devices produced for X-ray optics and power electronics applications. The usual first step for this characterization is white-beam X-ray diffraction topography, which is a simple and fast method to identify the extended defects (dislocations, growth sectors, boundaries, stacking faults, overall curvature etc.) within the crystal. This allows easy and quick comparison of the crystal quality of diamond plates available from various commercial suppliers. When needed, rocking curve imaging (RCI) is also employed, which is the quantitative counterpart of monochromatic Bragg diffraction imaging. RCI enables the local determination of both the effective misorientation, which results from lattice parameter variation and the local lattice tilt, and the local Bragg position. Maps derived from these parameters are used to measure the magnitude of the distortions associated with polishing damage and the depth of this damage within the volume of the crystal. For overgrown layers, these maps also reveal the distortion induced by the incorporation of impurities such as boron, or the lattice parameter variations associated with the presence of growth-incorporated nitrogen. These techniques are described, and their capabilities for studying the quality of diamond substrates and overgrown layers, and the surface damage caused by mechanical polishing, are illustrated by examples. PMID:28381981

  13. Educational Software for Interference and Optical Diffraction Analysis in Fresnel and Fraunhofer Regions Based on MATLAB GUIs and the FDTD Method

    Science.gov (United States)

    Frances, J.; Perez-Molina, M.; Bleda, S.; Fernandez, E.; Neipp, C.; Belendez, A.

    2012-01-01

    Interference and diffraction of light are elementary topics in optics. The aim of the work presented here is to develop an accurate and cheap optical-system simulation software that provides a virtual laboratory for studying the effects of propagation in both time and space for the near- and far-field regions. In laboratory sessions, this software…

  14. Report on the Radiation Effects Testing of the Infrared and Optical Transition Radiation Camera Systems

    Energy Technology Data Exchange (ETDEWEB)

    Holloway, Michael Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-20

    Presented in this report are the results tests performed at Argonne National Lab in collaboration with Los Alamos National Lab to assess the reliability of the critical 99Mo production facility beam monitoring diagnostics. The main components of the beam monitoring systems are two cameras that will be exposed to radiation during accelerator operation. The purpose of this test is to assess the reliability of the cameras and related optical components when exposed to operational radiation levels. Both X-ray and neutron radiation could potentially damage camera electronics as well as the optical components such as lenses and windows. This report covers results of the testing of component reliability when exposed to X-ray radiation. With the information from this study we provide recommendations for implementing protective measures for the camera systems in order to minimize the occurrence of radiation-induced failure within a ten month production run cycle.

  15. Optimizing the coupling of output of a quasi-optical gyrotron owing to a diffraction grating with ellipsoidal support

    International Nuclear Information System (INIS)

    Hogge, J.P.

    1993-12-01

    The output scheme of a quasi-optical gyrotron has been optimized in order to produce a gaussian output microwave beam suitable for transmission over long distances. The technique which has been applied consists of substituting one of the mirrors of the Fabry-Perot resonator in which the particle-wave interaction takes place by a diffraction grating placed in the -1 order Littrow mount and designed such that only orders -1 and 0 can propagate. In such a configuration, the diffraction angle of the order -1 coincides exactly with the incidence direction, thus providing a feedback in the cavity, whereas the order 0 constitutes the output of the resonator. A theoretical study of the power content in each diffracted order of a planar grating of infinite extent with equally spaced linear grooves as a function of the grating parameters has been performed. It has been shown that parameter domains can be found, which provide appropriate efficiencies in both orders for an application on a quasi-optical gyrotron. The Littrow condition was then adapted in order to match the spherical wavefronts of a gaussian beam incident on a possibly non-planar surface. The grooves become thus curvilinear and are no longer equally spaced. Measurements made on a cold test stand have confirmed the validity of the Littrow condition extension and allowed to determine its limits. It has also been shown that this type of cavity provides a mode having an optimal gaussian content and giving a minimal cavity transmission. The angular dispersion of the grating leads to a higher cavity transmission and to a slightly lower gaussian content for the adjacent resonator modes. The fundamental eigenmode electric field profile has been measured inside the cavity and is similar to that of an equivalent resonator made with two spherical mirrors. (author) figs., tabs., 141 refs

  16. Crystal structure of core streptavidin determined from multi-wavelength anomalous diffraction of synchrotron radiation

    International Nuclear Information System (INIS)

    Hendrickson, W.A.; Paehler, A.; Smith, J.L.; Satow, Y.; Merritt, E.A.; Phizackerley, R.P.

    1989-01-01

    A three-dimensional crystal structure of the biotin-binding core of streptavidin has been determined at 3.1-angstrom resolution. The structure was analyzed from diffraction data measured at three wavelengths from a single crystal of the selenobiotinyl complex with streptavidin. Streptavidin is a tetramer with subunits arrayed in D 2 symmetry. Each protomer is an 8-stranded β-barrel with simple up-down topology. Biotin molecules are bound at one end of each barrel. This study demonstrates the effectiveness of multi-wavelength anomalous diffraction (MAD) procedures for macromolecular crystallography and provides a basis for detailed study of biotin-avidin interactions

  17. Optical emission behavior and radiation resistance of epoxy resins

    International Nuclear Information System (INIS)

    Kawanishi, Shunichi; Udagawa, Akira; Hagiwara, Miyuki

    1987-11-01

    To make clear a mechanism of radiation resistance of epoxy resin systems, a role of energy trapping site induced in bisphenol A type epoxy resins cured with 4 kinds of aromatic amines (Φ N ) was studied in comparison with the case of aliphatic amine curing system through a measurement of optical emission. In the system of the epoxy resin cured with DETA, the optical emission from an excited state of bisphenol A unit of epoxy resin and a charge transfer complex was observed. On the other hand, the optical emission from Φ N was observed in the aromatic amine curing system. Their excitation spectrum consists of peaks of absorption spectrum of BA and those of Φ N , showing that the excited state of Φ N is formed through the excitation of both BA and Φ N . Therefore, the excited energy of BA transfers to the excited state of Φ N . Emission intensity of Φ N band was 20 ∼ 100 times as large as that of BA. These results indicate that the radiation energy is effectively released as an optical emission from excited state of Φ N in the epoxy resin when cured with aromatic amine. It can be concluded from the above results that aromatic amine hardeners contribute to enhancement of the radiation resistance of epoxy resin by acting as an energy transfer agent. (author)

  18. Radiation resistance characteristics of optical communication system for single mode

    International Nuclear Information System (INIS)

    Ohe, Masamoto; Chigusa, Yoshiki; Kyodo, Tomohisa; Tanaka, Gohtaro; Watanabe, Hajime; Okamoto, Shin-ichi; Yamamoto, Takao.

    1988-01-01

    Optical communication has been utilized also for nuclear power stations and fuel reporocessing plants. As the sufficient safety countermeasures are required there, the amount of information becomes enormous, therefore, optical communication, by which the required space is expected to be reduced, becomes more important. Also in the application to submarine cables, attention must be paid to the radiation resistance as there are the effects of potassium contained in large amount in seawater and uranium deposits in sea bottom. Therefore, the reliability of the components of optical communication systems against radiation becomes a problem. In this study, single mode optical fibers and transmission and receipt modules were selected, and high dose rate irradiation supposing the case of using in a cell and low dose rate, long time irradiation supposing the case of submarine cables were carried out to evaluate the radiation resistance characteristics. The fibers tested were SiO 2 core/F-SiO 2 clad type and GeO 2 -SiO 2 core/SiO 2 clad type. The characteristics of increasing loss in irradiation and restoration after irradiation of the former type were superior to those of the latter type. The output of a receipt module was normal during irradiation, and the output power of a transmission module decreases, but other problems did not arise. (K.I.)

  19. The cloud radiation impact from optics simulation and airborne observation

    Science.gov (United States)

    Melnikova, Irina; Kuznetsov, Anatoly; Gatebe, Charles

    2017-02-01

    The analytical approach of inverse asymptotic formulas of the radiative transfer theory is used for solving inverse problems of cloud optics. The method has advantages because it does not impose strict constraints, but it is tied to the desired solution. Observations are accomplished in extended stratus cloudiness, above a homogeneous ocean surface. Data from NASA`s Cloud Absorption Radiometer (CAR) during two airborne experiments (SAFARI-2000 and ARCTAS-2008) were analyzed. The analytical method of inverse asymptotic formulas was used to retrieve cloud optical parameters (optical thickness, single scattering albedo and asymmetry parameter of the phase function) and ground albedo in all 8 spectral channels independently. The method is free from a priori restrictions and there is no links to parameters, and it has been applied to data set of different origin and geometry of observations. Results obtained from different airborne, satellite and ground radiative experiments appeared consistence and showed common features of values of cloud parameters and its spectral dependence (Vasiluev, Melnikova, 2004; Gatebe et al., 2014). Optical parameters, retrieved here, are used for calculation of radiative divergence, reflected and transmitted irradiance and heating rates in cloudy atmosphere, that agree with previous observational data.

  20. Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Martin [Institut fuer Experimentelle und Angewandte Physik der Christian, Albrechts, Universitaet zu Kiel, Leibnizstr. 19, D-24098 Kiel (Germany)]. E-mail: mmueller@physik.uni-kiel.de; Murphy, Bridget [Institut fuer Experimentelle und Angewandte Physik der Christian, Albrechts, Universitaet zu Kiel, Leibnizstr. 19, D-24098 Kiel (Germany); Burghammer, Manfred [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Riekel, Christian [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex (France); Roberts, Mark [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Papiz, Miroslav [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Clarke, David [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Gunneweg, Jan [Institute of Archaeology, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem (Israel); Pantos, Emmanuel [Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom)

    2004-10-08

    Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context.

  1. Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

    International Nuclear Information System (INIS)

    Mueller, Martin; Murphy, Bridget; Burghammer, Manfred; Riekel, Christian; Roberts, Mark; Papiz, Miroslav; Clarke, David; Gunneweg, Jan; Pantos, Emmanuel

    2004-01-01

    Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context

  2. Identification of ancient textile fibres from Khirbet Qumran caves using synchrotron radiation microbeam diffraction

    Science.gov (United States)

    Müller, Martin; Murphy, Bridget; Burghammer, Manfred; Riekel, Christian; Roberts, Mark; Papiz, Miroslav; Clarke, David; Gunneweg, Jan; Pantos, Emmanuel

    2004-10-01

    Archaeological textiles fragments from the caves of Qumran in the Dead Sea region were investigated by means of X-ray microbeam diffraction on single fibres. This non-destructive technique made the identification of the used plant textile fibres possible. Apart from bast fibres (mainly flax), cotton was identified which was most unexpected in the archaeological context.

  3. Apparatus development for high-pressure X-ray diffraction using synchrotron radiation

    International Nuclear Information System (INIS)

    Martinez, L.G.; Orlando, M.T.D.; Rossi, J.L.; Passamai Junior, J.L.; Melo, F.C.L.; Ferreira, F.F.

    2006-01-01

    Some phenomena in the field of condensed matter physics can be studied when the matter is submitted to extreme conditions of pressure, magnetic fields or temperatures. Once submitted to these conditions it is generally necessary to measure the properties of the matter in situ. The existence of a synchrotron light laboratory in Brazil opens up the chance of studying materials in extreme conditions by techniques like X-ray diffraction and absorption. However, when compared to high-energy synchrotrons accelerators, the Brazilian source offers a narrower energy range and lower flux. These facts impose limitation to perform diffraction experiments by energy dispersion and, consequently, the use of pressure cells with denser anvils like diamond. However, for a lower-pressure range, preliminary studies showed the viability of measurements in an angular dispersion configuration. This allows the use of silicon carbide anvils B 4C . In this work it is described the development of a hydrostatic pressure cell suitable for X-rays diffraction measurements in the Brazilian Synchrotron Light Laboratory using materials and technologies developed by the institutions and researchers involved in this project (IPEN, UFES, CTA and LNLS). This development can provide the scientific community with the possibility of performing X-ray diffraction measurements under hydrostatic pressure, initially up to 2 GPa, with possibilities of increasing the maximum pressure to higher values, with or without application of magnetic fields and high or low temperatures. (author)

  4. Spatial resolution in optical transition radiation (OTR) beam diagnostics

    International Nuclear Information System (INIS)

    Castellano, M.; Verzilov, V. A.

    1998-06-01

    An evaluation of the OTR single particle image dimension is obtained using diffraction theory based on a realistic description of the radiation source. This approach allows the analysis of the effect of the finite size of the emitting screen and of the imaging system. The role of practical experimental conditions in treating the intensity tail problem is estimated. It is shown that by exploiting the polarization properties of OTR, a considerable enhancement in the spatial resolution can be achieved, which becomes very similar to that of a standard point source

  5. Radiation-induced attenuation in integrated optical materials

    International Nuclear Information System (INIS)

    Evans, B.D.

    1989-01-01

    This paper reports that three materials commonly employed in opto-electronic integrated circuits evaluated for radiation-induced optical attenuation in the range 300 nm to 3000 nm. These include optically clear epoxy and crystalline lithium niobate after Co-60 exposure and crystalline tellurium dioxide after mixed gamma/fast-neutron exposure. In all these materials, however, induced loss was restricted to shorter wavelengths; attenuation induced at the telecommunications windows near 850, 1300 and 1550 nm was <0.1 dB/cm

  6. Radiation resistance of electro-optic polymer-based modulators

    International Nuclear Information System (INIS)

    Taylor, Edward W.; Nichter, James E.; Nash, Fazio D.; Haas, Franz; Szep, Attila A.; Michalak, Richard J.; Flusche, Brian M.; Cook, Paul R.; McEwen, Tom A.; McKeon, Brian F.; Payson, Paul M.; Brost, George A.; Pirich, Andrew R.; Castaneda, Carlos; Tsap, Boris; Fetterman, Harold R.

    2005-01-01

    Mach-Zehnder interferometric electro-optic polymer modulators composed of highly nonlinear phenyltetraene bridge-type chromophores within an amorphous polycarbonate host matrix were investigated for their resistance to gamma rays and 25.6 MeV protons. No device failures were observed and the majority of irradiated modulators exhibited decreases in half-wave voltage and optical insertion losses compared to nonirradiated control samples undergoing aging processes. Irradiated device responses were attributed to scission, cross-linking, and free volume processes. The data suggests that strongly poled devices are less likely to de-pole under the influence of ionizing radiation

  7. Fiber optic components compatibility with the PWR containment radiation field

    International Nuclear Information System (INIS)

    Breuze, G.; Serre, J.

    1990-01-01

    Present and future applications of fiber optics transmission in the nuclear industrial field are emphasized. Nuclear acceptance criteria for relevant electronic equipments in terms of radiation dose rate, integrated dose and required reliability are given. Ambient conditions of PWR containment are especially considered in the present paper. Experimental results of optical fibers and end-components exposed to 60 Co gamma rays are successively shown. Main radiation response characteristics up to 10 4 Gy (with dose rates of about 100 Gy.h -1 ) of both multimodal fiber families (step index and gradient index fibers) are compared. Predominant features of pure silica core fibers are: * an efficient photobleaching with near IR light from LED and LD commonly used in transmission data links, * a radiation hardening reducing induced losses down to 10 dB.km -1 in fine fibers up to date with latest developments. Dose rate effect on induced losses is also outlined for these fibers. Optoelectronic fiber-end components radiation response is good only for special LED (AsGa) and PD (Si). Radiation behavior of complex pigtailed LDM (laser diode + photodiode + Peltier element + thermistor) is not fully acceptable and technological improvements were made. Preliminary results are given. Two applications of fiber links transmitting data in a PWR containment and a hot cell are described. Hardening levels obtained and means required are given

  8. Modeling silica aerogel optical performance by determining its radiative properties

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2016-02-01

    Full Text Available Silica aerogel has been known as a promising candidate for high performance transparent insulation material (TIM. Optical transparency is a crucial metric for silica aerogels in many solar related applications. Both scattering and absorption can reduce the amount of light transmitted through an aerogel slab. Due to multiple scattering, the transmittance deviates from the Beer-Lambert law (exponential attenuation. To better understand its optical performance, we decoupled and quantified the extinction contributions of absorption and scattering separately by identifying two sets of radiative properties. The radiative properties are deduced from the measured total transmittance and reflectance spectra (from 250 nm to 2500 nm of synthesized aerogel samples by solving the inverse problem of the 1-D Radiative Transfer Equation (RTE. The obtained radiative properties are found to be independent of the sample geometry and can be considered intrinsic material properties, which originate from the aerogel’s microstructure. This finding allows for these properties to be directly compared between different samples. We also demonstrate that by using the obtained radiative properties, we can model the photon transport in aerogels of arbitrary shapes, where an analytical solution is difficult to obtain.

  9. Modeling silica aerogel optical performance by determining its radiative properties

    Science.gov (United States)

    Zhao, Lin; Yang, Sungwoo; Bhatia, Bikram; Strobach, Elise; Wang, Evelyn N.

    2016-02-01

    Silica aerogel has been known as a promising candidate for high performance transparent insulation material (TIM). Optical transparency is a crucial metric for silica aerogels in many solar related applications. Both scattering and absorption can reduce the amount of light transmitted through an aerogel slab. Due to multiple scattering, the transmittance deviates from the Beer-Lambert law (exponential attenuation). To better understand its optical performance, we decoupled and quantified the extinction contributions of absorption and scattering separately by identifying two sets of radiative properties. The radiative properties are deduced from the measured total transmittance and reflectance spectra (from 250 nm to 2500 nm) of synthesized aerogel samples by solving the inverse problem of the 1-D Radiative Transfer Equation (RTE). The obtained radiative properties are found to be independent of the sample geometry and can be considered intrinsic material properties, which originate from the aerogel's microstructure. This finding allows for these properties to be directly compared between different samples. We also demonstrate that by using the obtained radiative properties, we can model the photon transport in aerogels of arbitrary shapes, where an analytical solution is difficult to obtain.

  10. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece

    OpenAIRE

    Lindfors, A. V.; Kouremeti, N.; Arola, A.; Kazadzis, S.; Bais, A. F.; Laaksonen, A.

    2013-01-01

    Pyranometer measurements of the solar surface radiation (SSR) are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD) using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, w...

  11. Improvements to optical performance in diffractive elements used for off-axis illumination

    Science.gov (United States)

    Welch, Kevin; Fedor, Adam; Felder, Daniel; Childers, John; Emig, Tim

    2009-08-01

    As photolithographic tools are pressed to print the ever shrinking features required in today's devices, complex off-axis illumination is taking an ever increasing role in meeting this challenge. This, in turn, is driving tighter, more stringent requirements on the diffractive elements used in these illumination systems. Specifically, any imbalance in the poles of an off-axis illuminator will contribute to reductions in the ultimate imaging performance of a lithographic tool and increased complexity in tool-to-tool matching. The article will focus on improvements to the manufacturing process that achieve substantially better pole balance. The modeling of the possible process contributors will be discussed. Challenges resulting from the manufacturing methodology will be shared. Finally, the improvement in manufacturing process performance will be reported by means of a pole balance capability index.

  12. Optical Fibre Temperature Sensor Based On A Blackbody Radiation

    Science.gov (United States)

    Hypszer, Ryszard; Plucinski, Jerzy; Wierzba, Henryk J.

    1990-01-01

    The principle of operation of the fibre optical temperature sensor based on a blackbody radiation and its construction model is given in the paper. A quartz rod of 0.6 mm diameter and 20 cm length with a blackbody cavity at the one end was used to construct the sensor. The cavity was made by vacuum evaporation of a chromium layer and a silicone monooxide layer was used as a protection. Infrared radiation is transmitted by the fibre optic to the detection circuit. This sensor enables temperature measurement from 400 to 1200°C. The range of measurement is determined by the detection sensitivity and by rod softening. The resolution is of the order of 10-2°C. The sensor calibration was done by using PtRh1O-Pt thermocouple.

  13. Optical components and systems for synchrotron radiation: an introduction

    International Nuclear Information System (INIS)

    Howells, M.R.

    1981-01-01

    A brief description of the nature and origins of synchrotron radiation is given with special reference to its geometrical optical properties and the use of storage rings as light souces. The geographical distribution of SR sources in the world is reviewed and some discussion of the level of experimental activity is given. Estimates of future levels of experimental activity are also made both for existing storage rings and those planned for the future. Calculations of the approximate number of mirrors and gratings that will be required are offered. Some general considerations are outlined showing how synchrotron radiation optical systems couple to the light source and indicating which parameters need to be maximized for best overall performance

  14. A Radiation Dosimetry Method Using Pulsed Optically Stimulated Luminescence

    International Nuclear Information System (INIS)

    Akselrod, M.S.; McKeever, S.W.S.

    1999-01-01

    A method for the determination of absorbed radiation dose is described based on pulsed optically stimulated luminescence (POSL). The method relies upon the stimulation of an irradiated sample with a train of light pulses from a suitable light source (e.g. a laser) using a wavelength which is within the range of wavelengths corresponding to the radiation-induced optical absorption in the irradiated sample. The subsequent emitted light, due to the detrapping of trapped charges and their subsequent recombination with charge of the opposite sign, is synchronously detected in the period between each stimulation pulse. The total luminescence is summed over the desired number of stimulation pulses and this forms the measured POSL signal. By monitoring the emitted light only in the period between stimulation pulses one can reduce the optical filtering required to discriminate between the stimulation light and the emission light; in this way a high measurement efficiency, and, therefore, a high radiation sensitivity (luminescence intensity per unit absorbed dose) is achieved. Key parameters in the method are the intrinsic luminescence lifetime for the material being used as the luminescent detector, the width of the optical stimulation pulse, and the period between pulses. For optimum operation the measurement parameters should be such that both the pulse width and the time between pulses are much less than the luminescence lifetime. By appropriate choice of the power of the optical stimulation, the frequency of the stimulation pulses, and the total stimulation period, one can also re-measure the absorbed dose several times. In this way, a re-read capability is available with the procedure. The method is illustrated using light from a 2nd-harmonic Nd:YAG laser, with irradiated, anion-deficient aluminium oxide as the luminescent detector material. (author)

  15. Crystal structure refinement of α-Si3N4 using synchrotron radiation powder diffraction data: unbiased refinement strategy

    International Nuclear Information System (INIS)

    Toraya, H.

    2000-01-01

    The crystal structure of α-silicon nitride (Si 3 N 4 ) was refined by the Rietveld method using synchrotron radiation powder diffraction data (wavelength = 1.2 A) collected at station BL-4B2 in the photon factory. A refinement procedure that adopted a new weight function, w = 1/Y o e (Y o is the observed profile intensity and e ≅ 2), for the least-squares fitting [Toraya (1998). J. Appl. Cryst. 31, 333-343] was studied. The most reasonable structural parameters were obtained with e = 1.7. Crystal data of α-Si 3 N 4 : trigonal, P31c, a = 7.75193 (3), c = 5.61949 (4) A, V = 292.447 (3) A 3 , Z = 4; R p = 5.08, R wp = 6.50, R B = 3.36, R F = 2.26%. The following five factors are considered equally important for deriving accurate structural parameters from powder diffraction data: (i) sufficiently large sin θ/λ range of >0.8 A -1 ; (ii) adequate counting statistics; (iii) correct profile model; (iv) proper weighting on observations to give a uniform distribution of the mean weighted squared residuals; (v) high-angular-resolution powder diffraction data. (orig.)

  16. Optical properties of the PANDA barrel DIRC radiator bars

    Energy Technology Data Exchange (ETDEWEB)

    Kalicy, Grzegorz; Krebs, Marvin; Peters, Klaus [GSI, Darmstadt (Germany); Goethe Universitaet, Frankfurt (Germany); Schwarz, Carsten; Schwiening, Jochen [GSI, Darmstadt (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    The PANDA experiment at the Facility for Antiproton and Ion Research in Europe (FAIR) at GSI, Darmstadt, will study fundamental questions of hadron physics and QCD. A fast focusing DIRC (Detection of Internally Reflected Cherenkov light) counter will provide hadronic particle identification (PID) in the barrel region of the PANDA detector. To meet the PID requirements, the Barrel DIRC has to provide precise measurements of the Cherenkov angle, which is conserved for Cherenkov photons propagating through the radiator by total internal reflection. The radiators, rectangular bars made from fused silica, have to fulfill very strict optical and mechanical requirements. This includes the squareness and parallelism of the sides of the bars, sharp corners, and a very smooth surface polish, ensuring that the Cherenkov photons reach the optical sensors without angular distortions. Currently the Barrel DIRC is at the final design stage and several different bar shapes and fabrication methods are being considered for the final detector. An optical setup, consisting of a computer-controlled positioning and a multi-wavelength laser system, is used to evaluate the radiator bars to obtain critical values like transmittance and reflectivity. The current results and techniques are presented on this poster.

  17. Large deflection angle, high-power adaptive fiber optics collimator with preserved near-diffraction-limited beam quality.

    Science.gov (United States)

    Zhi, Dong; Ma, Yanxing; Chen, Zilun; Wang, Xiaolin; Zhou, Pu; Si, Lei

    2016-05-15

    We report on the development of a monolithic adaptive fiber optics collimator, with a large deflection angle and preserved near-diffraction-limited beam quality, that has been tested at a maximal output power at the 300 W level. Additionally, a new measurement method of beam quality (M2 factor) is developed. Experimental results show that the deflection angle of the collimated beam is in the range of 0-0.27 mrad in the X direction and 0-0.19 mrad in the Y direction. The effective working frequency of the device is about 710 Hz. By employing the new measurement method of the M2 factor, we calculate that the beam quality is Mx2=1.35 and My2=1.24, which is in agreement with the result from the beam propagation analyzer and is preserved well with the increasing output power.

  18. 15x optical zoom and extreme optical image stabilisation: diffraction limited integral field spectroscopy with the Oxford SWIFT spectrograph

    OpenAIRE

    Tecza, Matthias; Thatte, Niranjan; Clarke, Fraser; Lynn, James; Freeman, David; Roberts, Jennifer; Dekany, Richard

    2012-01-01

    When commissioned in November 2008 at the Palomar 200 inch Hale Telescope, the Oxford SWIFT I and z band integral field spectrograph, fed by the adaptive optics system PALAO, provided a wide (3×) range of spatial resolutions: three plate scales of 235 mas, 160 mas, and 80 mas per spaxel over a contiguous field-of-view of 89×44 pixels. Depending on observing conditions and guide star brightness we can choose a seeing limited scale of 235 mas per spaxel, or 160 mas and 80 mas per spaxel for ver...

  19. Modulatable optical radiators and metasurfaces based on quantum nanoantennas

    KAUST Repository

    Chen, Pai-Yen; Farhat, Mohamed

    2015-01-01

    We investigate the tunable and switchable optical radiators and metamaterials formed by metallic nanodipole antennas with submicroscopic gaps (1.2 nm), of which linear and third-order nonlinear quantum conductivities are observed due to the photon-assisted tunneling effect. The quantum conductivities induced at the nanogap are relevant to power dissipations, which can be enhanced by the strongly localized optical fields associated with the plasmonic resonance. We demonstrate that the scattering property of an individual quantum nanoantenna and the transparency of a metamasurface constituted of it can be tuned by electrostatically controlling the linear conductivity (electronic tuning) or by adjusting the irradiation intensity that varies the nonlinear quantum conductivity (all-optical tuning).

  20. Modulatable optical radiators and metasurfaces based on quantum nanoantennas

    KAUST Repository

    Chen, Pai-Yen

    2015-01-20

    We investigate the tunable and switchable optical radiators and metamaterials formed by metallic nanodipole antennas with submicroscopic gaps (1.2 nm), of which linear and third-order nonlinear quantum conductivities are observed due to the photon-assisted tunneling effect. The quantum conductivities induced at the nanogap are relevant to power dissipations, which can be enhanced by the strongly localized optical fields associated with the plasmonic resonance. We demonstrate that the scattering property of an individual quantum nanoantenna and the transparency of a metamasurface constituted of it can be tuned by electrostatically controlling the linear conductivity (electronic tuning) or by adjusting the irradiation intensity that varies the nonlinear quantum conductivity (all-optical tuning).

  1. Fiber-optic-coupled dosemeter for remote optical sensing of radiation

    International Nuclear Information System (INIS)

    Justus, B.L.; Huston, A.L.

    1996-01-01

    Remote sensing technologies for the detection and measurement of ionizing radiation exposure are of current interest for applications such as patient dose verification during radiotherapy and the monitoring of environmental contaminants. Fiberoptic-based sensing is attractive due to the advantages of small size, low cost, long life and freedom from electromagnetic interference. Several fiberoptic-based radiation sensing systems have been described that utilize radiation induced changes in the optical characteristics of the fiber such as reduced transmission as a result of darkening of the glass, optical phase shifts due to heating, or changes in the birefringence of a polarization-maintaining fiber. The measurement of radiation induced darkening is limited in both sensitivity and dynamic range and requires long fiber lengths. Phase shift measurements require the use of single-mode lasers, phase sensitive interferometric detection, long fiber lengths and complex signal processing techniques. Alternatively, thermoluminescent (TL) phosphor powders have been coated onto fiberoptic cables and remote dosimetry measurements performed using traditional laser heating techniques. The sensitivity is limited by the requirement for a very thin layer of phosphor material, due to problems associated with light scattering and efficient heating by thermal diffusion. In this paper we report the development of an all-optical, fiber-optic-coupled, thermoluminescence dosemeter for remote radiation sensing that offers significant advantages compared to previous technologies. We recently reported the development of an optically transparent, TL glass material having exceptionally good characteristics for traditional dosimetry applications. We also reported a modified TL glass incorporating a rare earth ion dopant in order to absorb light from a semiconductor laser and utilize the absorbed light energy to internally heat the glass and release the trapped electrons. (author)

  2. Performances for confocal X-ray diffraction technology based on polycapillary slightly focusing X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hehe; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stxbeijing@163.com [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Peng, Song [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Sun, Weiyuan; Li, Yude; Lin, Xiaoyan; Zhao, Weigang; Zhao, Guangcui; Luo, Ping; Pan, Qiuli; Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2013-09-21

    The confocal X-ray diffraction (XRD) technology based on a polycapillary slightly focusing X-ray lens (PSFXRL) in excitation channel and a polycapillary parallel X-ray lens (PPXRL) with a long input focal distance in detection channel was developed. The output focal spot of the PSFXRL and the input focal spot of the PPXRL were adjusted in confocal configuration, and only the X-rays from the volume overlapped by these foci could be accordingly detected. This confocal configuration was helpful in decreasing background. The convergence of the beam focused by the PSFXRL and divergence of the beam which could be collected by the PPXRL with a long input focal distance were both about 9 mrad at 8 keV. This was helpful in improving the resolution of lattice spacing of this confocal XRD technology. The gain in power density of such PSFXRL and PPXRL was about 120 and 7 at 11 keV, respectively, which was helpful in using the low power source to perform XRD analysis efficiently. The performances of this confocal XRD technology were provided, and some common plastics were analyzed. The experimental results demonstrated that the confocal diffraction technology base on polycapillary slightly focusing X-ray optics had wide potential applications.

  3. Extraordinary optical transmission with tapered slits: effect of higher diffraction and slit resonance orders

    DEFF Research Database (Denmark)

    Sondergaard, T.; Bozhevolnyi, S. I.; Beermann, J.

    2012-01-01

    Transmission through thin metal films with a periodic arrangement of tapered slits is considered. Transmission maps covering a wide range of periods, film thicknesses, and taper angles are presented. The maps show resonant transmission when fundamental and higher-order slit resonances are excited...... to be in the range of 6 degrees-10 degrees. Both theory and experiments show split-peak spectra and shifted-peak spectra due to interference between a slit resonance and Rayleigh-Wood anomalies. (C) 2011 Optical Society of America...

  4. Development of a distributed radiation detection system using optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, F; Inouchi, Goro; Takada, Eiji; Takahashi, Hiroyuki; Iguchi, Tetsuo; Nakazawa, Masaharu [Tokyo Univ. (Japan). Faculty of Engineering; Kakuta, Tsunemi

    1996-07-01

    We have confirmed the importance of temperature and dose rate for the response of Ge-doped fibers to radiation. A phenomenological model have been found to account for temperature and dose rate effects. From this model it is possible to make dose predictions from attenuation measurements when the temperature and dose rate are known. Ge-doped fibers have been found to have a relatively low sensitivity to both neutron and gamma radiation. In addition, temperature and dose rate dependencies complicate the analysis. However we point out that these problems may all be solved if we use fibers, such as P-doped fibers, which contain color centers of long lifetime. This would remove both the temperature and dose rate dependencies that complicate the use of Ge-doped fibers, in addition the radiation sensitivity is increased. Finally OTDR has been investigated as a possible read-out method for distributed radiation measurements. For our system the minimum pulse length was 3ns, giving a spatial resolution in the meter range and a response length to radiation of about 10 m if accurate dose values where to be obtained. We found OTDR to be a suitable method for radiation induced attenuation measurements in optical fibers, especially for long fiber lengths and long time scales where questions of light source stability becomes important for other systems. (S.Y.)

  5. High power beam profile monitor with optical transition radiation

    International Nuclear Information System (INIS)

    Denard, J.C.; Piot, P.; Capek, K.; Feldl, E.

    1997-01-01

    A simple monitor has been built to measure the profile of the high power beam (800 kW) delivered by the CEBAF accelerator at Jefferson Lab. The monitor uses the optical part of the forward transition radiation emitted from a thin carbon foil. The small beam size to be measured, about 100 μm, is challenging not only for the power density involved but also for the resolution the instrument must achieve. An important part of the beam instrumentation community believes the radiation being emitted into a cone of characteristic angle 1/γ is originated from a region of transverse dimension roughly λγ; thus the apparent size of the source of transition radiation would become very large for highly relativistic particles. This monitor measures 100 μm beam sizes that are much smaller than the 3.2 mm λγ limit; it confirms the statement of Rule and Fiorito that optical transition radiation can be used to image small beams at high energy. The present paper describes the instrument and its performance. The authors tested the foil in, up to 180 μA of CW beam without causing noticeable beam loss, even at 800 MeV, the lowest CEBAF energy

  6. Radiation - induced changes in the optical properties of hemoglobin molecule

    International Nuclear Information System (INIS)

    Selim, N.S; El-Marakby, S.M.

    2009-01-01

    Adult male albino rats were exposed to different doses of gamma radiation from Cs-137 source. Hemoglobin samples were analyzed 24 hrs after irradiation. The UV-visible spectrum of hemoglobin molecule was measured in the range 200 to 700 nm. The overall spectrum of the hemoglobin molecule showed hypochromicity that increased with dose increase. To investigate the effect of radiation on the hemoglobin molecule, different parameters of the spectrum were calculated: molar absorption coefficient, absorption cross section, transition dipole moment , dipole length, the optical energy gap and activation energy for each characteristic peak. The obtained results revealed that the radiation effect can induce rearrangement of the transition dipole moments and change molecular energy levels of the hemoglobin molecule

  7. Optical properties and radiation response of Ce3+-doped GdScO3 crystals

    International Nuclear Information System (INIS)

    Yamaji, Akihiro; Fujimoto, Yutaka; Futami, Yoshisuke; Yokota, Yuui; Kurosawa, Shunsuke; Kochurikhin, Vladimir; Yanagida, Takayuki; Yoshikawa, Akira

    2012-01-01

    10%-Ce doped GdScO 3 perovskite type single crystal was grown by the Czochralski process. The Ce concentration in the crystal was measured. No impurity phases were observed by powder X-ray diffraction analysis. We evaluated the optical and radiation properties of the grown crystal. Ce:GdScO 3 crystal showed photo- and radio-luminescence peaks due to Ce 3+ of 5d-4f transition and colour centre. The photoluminescence decay time was sub-ns order. The relative light yield under 5.5 MeV alpha-ray excitation was calculated to be approximately 9% of BGO. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Analysis of the frequency response of a TeO{sub 2} slow shear wave acousto-optic cell exposed to radiation

    Energy Technology Data Exchange (ETDEWEB)

    Erteza, I.A.

    1995-04-01

    Radiation testing of photonic components is not new, however component level testing to date has not completely addressed quantities which are important to system behavior. One characteristic that is of particular importance for optical processing systems is the frequency response. In this report, we present the analysis of data from an experiment designed to provide a preliminary understanding of the effects of radiation on the frequency response of acousto-optic devices. The goal of the analysis is to describe possible physical mechanisms responsible for the radiation effects and to discuss the effects on signal processing functionality. The experiment discussed in this report was designed by Sandia National Laboratories and performed by Sandia and Phillips Laboratory personnel at White Sands Missile Range (WSMR). In the experiment, a TeO{sub 2} slow shear wave acousto-optic cell was exposed to radiation from the WSMR linear accelerator. The TeO{sub 2} cell was placed in an experimental configuration which allowed swept frequency diffracted power measurements to be taken during radiation exposure and recovery. A series of exposures was performed. Each exposure consisted of between 1 to 800, 1{mu}sec radiation pulses (yielding exposures of 2.25 kRad(Si) to 913 kRad(Si)), followed by recovery time. At low total and cumulative doses, the bandshape of the frequency response (i.e. diffracted power vs. frequency) remained almost identical during and after radiation. At the higher exposures, however, the amplitude and width of the frequency response changed as the radiation continued, but returned to the original shape slowly after the radiation stopped and recovery proceeded. It is interesting to note that the location of the Bragg degeneracy does not change significantly with radiation. In this report, we discuss these effects from the perspective of anisotropic Bragg diffraction and momentum mismatch, and we discuss the effect on the signal processing functionality.

  9. Radiation imaging with optically read out GEM-based detectors

    Science.gov (United States)

    Brunbauer, F. M.; Lupberger, M.; Oliveri, E.; Resnati, F.; Ropelewski, L.; Streli, C.; Thuiner, P.; van Stenis, M.

    2018-02-01

    Modern imaging sensors allow for high granularity optical readout of radiation detectors such as MicroPattern Gaseous Detectors (MPGDs). Taking advantage of the high signal amplification factors achievable by MPGD technologies such as Gaseous Electron Multipliers (GEMs), highly sensitive detectors can be realised and employing gas mixtures with strong scintillation yield in the visible wavelength regime, optical readout of such detectors can provide high-resolution event representations. Applications from X-ray imaging to fluoroscopy and tomography profit from the good spatial resolution of optical readout and the possibility to obtain images without the need for extensive reconstruction. Sensitivity to low-energy X-rays and energy resolution permit energy resolved imaging and material distinction in X-ray fluorescence measurements. Additionally, the low material budget of gaseous detectors and the possibility to couple scintillation light to imaging sensors via fibres or mirrors makes optically read out GEMs an ideal candidate for beam monitoring detectors in high energy physics as well as radiotherapy. We present applications and achievements of optically read out GEM-based detectors including high spatial resolution imaging and X-ray fluorescence measurements as an alternative readout approach for MPGDs. A detector concept for low intensity applications such as X-ray crystallography, which maximises detection efficiency with a thick conversion region but mitigates parallax-induced broadening is presented and beam monitoring capabilities of optical readout are explored. Augmenting high resolution 2D projections of particle tracks obtained with optical readout with timing information from fast photon detectors or transparent anodes for charge readout, 3D reconstruction of particle trajectories can be performed and permits the realisation of optically read out time projection chambers. Combining readily available high performance imaging sensors with compatible

  10. Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

    International Nuclear Information System (INIS)

    Rofouie, P.; Rey, A. D.; Pasini, D.

    2015-01-01

    Periodic surface nano-wrinkling is found throughout biological liquid crystalline materials, such as collagen films, spider silk gland ducts, exoskeleton of beetles, and flower petals. These surface ultrastructures are responsible for structural colors observed in some beetles and plants that can dynamically respond to external conditions, such as humidity and temperature. In this paper, the formation of the surface undulations is investigated through the interaction of anisotropic interfacial tension, swelling through hydration, and capillarity at free surfaces. Focusing on the cellulosic cholesteric liquid crystal (CCLC) material model, the generalized shape equation for anisotropic interfaces using the Cahn-Hoffman capillarity vector and the Rapini-Papoular anchoring energy are applied to analyze periodic nano-wrinkling in plant-based plywood free surfaces with water-induced cholesteric pitch gradients. Scaling is used to derive the explicit relations between the undulations’ amplitude expressed as a function of the anchoring strength and the spatially varying pitch. The optical responses of the periodic nano-structured surfaces are studied through finite difference time domain simulations indicating that CCLC surfaces with spatially varying pitch reflect light in a wavelength higher than that of a CCLC’s surface with constant pitch. This structural color change is controlled by the pitch gradient through hydration. All these findings provide a foundation to understand structural color phenomena in nature and for the design of optical sensor devices

  11. Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

    Energy Technology Data Exchange (ETDEWEB)

    Rofouie, P.; Rey, A. D., E-mail: alejandro.rey@mail.mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2 (Canada); Pasini, D. [Department of Mechanical Engineering, McGill University, 817 Sherbrook West, Montreal, Quebec H3A 0C3 (Canada)

    2015-09-21

    Periodic surface nano-wrinkling is found throughout biological liquid crystalline materials, such as collagen films, spider silk gland ducts, exoskeleton of beetles, and flower petals. These surface ultrastructures are responsible for structural colors observed in some beetles and plants that can dynamically respond to external conditions, such as humidity and temperature. In this paper, the formation of the surface undulations is investigated through the interaction of anisotropic interfacial tension, swelling through hydration, and capillarity at free surfaces. Focusing on the cellulosic cholesteric liquid crystal (CCLC) material model, the generalized shape equation for anisotropic interfaces using the Cahn-Hoffman capillarity vector and the Rapini-Papoular anchoring energy are applied to analyze periodic nano-wrinkling in plant-based plywood free surfaces with water-induced cholesteric pitch gradients. Scaling is used to derive the explicit relations between the undulations’ amplitude expressed as a function of the anchoring strength and the spatially varying pitch. The optical responses of the periodic nano-structured surfaces are studied through finite difference time domain simulations indicating that CCLC surfaces with spatially varying pitch reflect light in a wavelength higher than that of a CCLC’s surface with constant pitch. This structural color change is controlled by the pitch gradient through hydration. All these findings provide a foundation to understand structural color phenomena in nature and for the design of optical sensor devices.

  12. X-ray detectors for diffraction studies and their use with synchrotron radiation

    International Nuclear Information System (INIS)

    Milch, J.

    1976-02-01

    All techniques for X-ray diffraction studies on biological materials exhibit certain limitations. The characteristics of several X-ray detection systems, namely film, multiwire proportional counter and image intensified TV, are discussed and compared for application to specific biological studies. For the high count-rate situation existing at a synchrotron, it is shown that film is a good choice, but that the image intensified TV exhibits significant advantages. The details of such a system now being used at Princeton with a low intensity source are given and current results presented

  13. Evaluation of Optical Quality: Ocular Scattering and Aberrations in Eyes Implanted with Diffractive Multifocal or Monofocal Intraocular Lenses.

    Science.gov (United States)

    Liao, Xuan; Lin, Jia; Tian, Jing; Wen, BaiWei; Tan, QingQing; Lan, ChangJun

    2018-06-01

    To compare objective optical quality, ocular scattering and aberrations of eyes implanted with an aspheric monofocal intraocular lens (IOL) or an aspheric apodized diffractive multifocal IOL three months after surgery. Prospective consecutive nonrandomized comparative cohort study. A total of 80 eyes from 57 cataract patients were bilaterally or unilaterally implanted with monofocal (AcrySof IQ SN60WF) or multifocal (AcrySof IQ ReSTOR SN6AD1) IOLs. Respectively, 40 eyes of 27 patients were implanted with monofocal IOLs, and 40 eyes of 30 patients were implanted with multifocal IOLs. Ocular high-order aberration (HOA) values were obtained using Hartmann-Shack aberrometer; objective scatter index (OSI), modulation transfer function (MTF) cutoff, Strehl ratio (SR), and contrast visual acuity OV at 100%, 20%, and 9% were measured using Objective Quality Analysis System II (OQAS II). Ocular aberrations performed similar in both groups (p > 0.05). However, significantly higher values of OSI and lower values of MTF cutoff, SR and OV were found in the SN6AD1 group (p < 0.05). Both ocular scattering and wave-front aberrations play essential role in retinal image quality, which may be overestimated when only aberrations were taken into account. Combining the effect of ocular scattering with HOA will result in a more accurate assessment of the visual and optical quality.

  14. Improvement of diffraction efficiency of three-dimensional magneto-optic spatial light modulator with magnetophotonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K.; Takagi, H., E-mail: takagi@ee.tut.ac.jp; Lim, P. B.; Inoue, M., E-mail: inoue@tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441 8580 (Japan); Goto, Taichi [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441 8580 (Japan); JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Horimai, H. [HolyMine Corporation, Atsugi, Kanagawa 243 0813 (Japan); Yoshikawa, H. [Department of Computer Engineering, College of Science and Technology, Nihon University, Funabashi, Chiba 274 8501 (Japan); Bove, V. M. [MIT Media Lab, Cambridge, Massachusetts 02139 (United States)

    2016-01-11

    We have developed three-dimensional magneto-optic spatial light modulators (3D-MOSLMs) that use magnetic domains as submicron scale pixels to represent holograms. Our display system uses a submicron-scale magnetic pixel array on an amorphous TbFe film to create a wide viewing angle hologram. However, in previous work the reconstructed images had a low intensity and a low optical contrast; brightness of the reconstructed image was 4.4 × 10{sup −2 }cd/m{sup 2} with 532 nm illumination light at 10.8 mW/cm{sup 2}, while display standard ISO13406 recommends 100 cd/m{sup 2} or more. In this paper, we describe our development of a 3D-MOSLM composed of an artificial magnetic lattice structure of magnetophotonic crystals (MPCs). The MPCs enhance the diffraction efficiency of reconstructed 3D images and reduce the power consumption for controlling the magnetic pixels by a light localization effect. We demonstrate reconstructed 3D images using the MPC and show significant brightness improvement.

  15. Design and Fabrication of Radiation Shielded Micro X-Ray Diffraction System

    International Nuclear Information System (INIS)

    Park, Yang Soon; Han, Sun Ho; Ha, Kyeong Yeong; Jee, Kwang Yong

    2006-12-01

    It has been observed that microstructure changes occur at the radial edge of pellet(rim) of the fuel at a high burn-up and extended fuel cycle. The thickness of a rim is some hundreds of micrometers. Despite its narrow range, a rim would affect the behaviour of nuclear fuel. To determine lattice parameter with micro-XRD at intervals as small as 30 - 50 μm in radial direction of irradiated fuel samples, a radiation shielded micro-XRD system was designed and fabricated. This report describes the concept, shielding analysis, the structural design and the fabrication of a radiation shielded glove box for micro-XRD system. This radiation shielded micro-XRD system will be used for analysis of lattice parameter change and the phase distribution at intervals as small as 30 - 50 μm in radial direction of the rim of an irradiated fuel sample and a fuel cladding

  16. Design and Fabrication of Radiation Shielded Micro X-Ray Diffraction System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yang Soon; Han, Sun Ho; Ha, Kyeong Yeong; Jee, Kwang Yong

    2006-12-15

    It has been observed that microstructure changes occur at the radial edge of pellet(rim) of the fuel at a high burn-up and extended fuel cycle. The thickness of a rim is some hundreds of micrometers. Despite its narrow range, a rim would affect the behaviour of nuclear fuel. To determine lattice parameter with micro-XRD at intervals as small as 30 - 50 {mu}m in radial direction of irradiated fuel samples, a radiation shielded micro-XRD system was designed and fabricated. This report describes the concept, shielding analysis, the structural design and the fabrication of a radiation shielded glove box for micro-XRD system. This radiation shielded micro-XRD system will be used for analysis of lattice parameter change and the phase distribution at intervals as small as 30 - 50 {mu}m in radial direction of the rim of an irradiated fuel sample and a fuel cladding.

  17. Irradiation behavior of developed radiation resistance optical-fibers and observed optical radiation from their SiO2 cores under reactor irradiation

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Narui, Minoru; Kayano, Hideo; Kakuta, Tsunemi; Sagawa, Tsutomu; Sanada, Kazuo; Shamoto, Naoki; Uramoto, Toshimasa.

    1994-01-01

    Two kinds of optical fibers were irradiated in a fission reactor, JMTR(Japan Materials Testing Reactor), up to a 1.55x10 19 n/cm 2 fast neutron fluence and a 3.3x10 9 Gy ionizing dose at 370K. Optical transmission spectra were measured in the wavelength range of 450-1750nm, in-situ. Growth of strong optical absorption bands were observed in the range of wavelength shorter than 750nm. In the meantime, the fibers showed good radiation-resistance in the range of wavelength longer than 750nm. Optical radiations were observed from SiO 2 optical fibers under irradiation. A major part of the observed optical radiations is thought to be composed of broad optical radiation in the whole wavelength range studied in the present experiment. This broad optical radiation will be generated by the process of so-called Cerenkov radiation. Also, a sharp optical radiation peak was found at 1270nm on a F-doped fiber. This peak is thought to relate with doped Fluorine ions and ionizing gamma-ray irradiation. (author)

  18. Effect of gamma radiation on the structural and optical properties of Polyethyleneterephthalate (PET) polymer

    International Nuclear Information System (INIS)

    Siddhartha; Aarya, Suveda; Dev, Kapil; Raghuvanshi, Suresh Kumar; Krishna, J.B.M.; Wahab, M.A.

    2012-01-01

    Effect of 1.25 MeV gamma radiation on the structural and optical properties of virgin and gamma irradiated (0–2000 kGy) Polyethyleneterephthalate (PET) polymer samples are analyzed using powder X-ray diffractometer and UV–vis spectrophotometer. Diffraction pattern of PET polymer indicates the semi-crystalline in nature whereas the crystallinity increases with increasing dose of irradiation. The remarkable variation in crystallite size is also observed. The absorption and activation energy increase and the optical band gap (E g ) decreases with increasing dose in UV–vis studies. The existence of the maximum absorption, their shifting and broadening due to gamma irradiation in PET polymer are also discussed. - Highlights: ► PET is the transparent polymer and semi- crystalline. ► Crystallinity increases with increasing dose of irradiation of polymer. ► The remarkable variation in crystallite sizes was also observed in polymer. ► The absorption and activation energy increase and where as the optical band gap (E g ) decrease with increasing dose.

  19. Feasibility Study on Fiber-optic Radiation Sensor for Remote Gamma-ray Spectroscopy

    International Nuclear Information System (INIS)

    Jeon, Hyesu; Jang, Kyoung Won; Shin, Sang Hun and others

    2014-01-01

    In this study, we fabricated a fiber-optic radiation sensor using an optical fiber and various scintillators. To select an adequate inorganic scintillator for the sensing probe of fiber-optic radiation sensor, 5 types of scintillators were evaluated. The spectra of gamma-rays emitted from a Na-22 radiation source were measured by using the manufactured sensors. As a result, the BGO was suitable for the sensing probe of fiber-optic radiation sensor due to its high scintillation output and exact photoelectric peak for the gamma-ray energy. The basic principle of radiation detection is to detect the signals caused by interactions between radiations and materials. There are various types of radiation detectors depending on types of radiation to be detected and physical quantities to be measured. As one of the radiation detectors, a fiber-optic radiation sensor using a scintillator and an optical fiber has two advantages such as no space restraint and remote sensing. Moreover, in nuclear environments, this kind of sensor has immunities for electromagnetic field, temperature, and pressure. Thus, the fiber-optic radiation sensor can be used in various fields including nondestructive inspection, radioactive waste management, nuclear safety, radiodiagnosis and radiation therapy. As a fundamental study of the fiber-optic radiation sensor for remote gamma-ray spectroscopy, in this study, we fabricated a fiber-optic radiation sensor using an optical fiber and various scintillators. To select an adequate inorganic scintillator for the sensing probe of fiber-optic radiation sensor, 5 types of scintillators were evaluated. The spectra of gamma-rays emitted from a Na-22 radiation source were measured by using the manufactured sensors

  20. Nuclear radiation detected optical pumping of neutron deficient Hg isotopes

    International Nuclear Information System (INIS)

    Bonn, J.

    1975-01-01

    The extension of the Nuclear Radiation Detected Optical Pumping method to mass-separated samples of isotopes far off stability is presented for a series of light Hg isotopes produced at the ISOLDE facility at CERN. The isotope under investigation is transferred by an automatic transfer system into the optical pumping apparatus. Zeeman scanning of an isotopically pure Hg spectral lamp is used to reach energetic coincidence with the hyperfine structure components of the 6s 2 1 S 0 -6s6p 3 P 1 (lambda = 2537 A) resonance line of the investigated isotope and the Hg lamp. The orientation build up by optical pumping is monitored via the asymmetry or anisotropy of the nuclear radiation. Nuclear spins, magnetic moments, electric quadrupole moments and isotopic shift are obtained for 181 Hg- 191 Hg using the β-asymmetry as detector. The extension of the method using the γ-anisotropy is discussed and measurements on 193 Hg are presented. (orig./HK)

  1. Optical transition radiation interferometry for A0 photoinjector

    International Nuclear Information System (INIS)

    Kazakevich, G.; Novosibirsk, IYF; Edwards, H.; Fliller, R.; Lebedev, V.; Nagaitsev, S.; Santucci, J.; Thurman-Keup, R.; Fermilab; Piot, P.; Fermilab; Northern Illinois U.; Li, J.; Tikhoplav, R.; UCLA

    2007-01-01

    A charged particle passing through the boundary of two medias with different permittivity values generates Transition Radiation (TR), [1]. The TR is caused by a variation of the particle electric field with variation of the permittivity. The TR for relativistic particles has a wide spectrum with a significant portion in the optical range. The Optical Transition Radiation (OTR) is widely used for a beam profile monitoring and measurements of a beam size. Moreover, OTR can be used to characterize the energy, energy spread and transverse angles in the beam by employing the interference of the OTR from two thin films [2] inserted in the beam trajectory. This method has been applied in number of works [3-5] demonstrating high results and good coincidence in measurements and calculations. In this paper we present and discuss in details a simulation of the interference pattern in several experimental setups. We consider the main optical effects, for diagnostics for the beam properties at A0 Photoinjector and the ILC module test area (NML) in a wide range of electron beam energy. In this paper, we first derive the OTR intensity formula for a single film at 90 degrees to the beam, then for two films at normal incidence, and finally with films at 45 degree incidence to the beam. The last section illustrates application with beam parameters like those at the A0 Photoinjector (electron energy 15 MeV)

  2. High-pressure x-ray diffraction study on lithium borohydride using a synchrotron radiation

    Science.gov (United States)

    Nakano, S.; Nakayama, A.; Kikegawa, T.

    2008-07-01

    Lithium borohydride (LiBH4) was compressed up to 10 GPa using a diamond-anvil-cell to investigate its high-pressure structure. In-situ x-ray diffraction profiles indicated a pressure-induced transformation at 1.1 GPa, which was consistent with the previous experimental observation such as Raman scattering spectroscopy. The high-pressure phase was indexed on a tetragonal symmetry of P42/mmc, which was not corresponding some structural models proposed by previous calculation studies. An unknown substance (presumably another Li-B-H compound), which was contained in the starting material, also transformed into its high-pressure phase at 0.6 GPa without any relation to the transformation of LiBH4.

  3. High-pressure x-ray diffraction study on lithium borohydride using a synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, S [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Nakayama, A [Department of Materials Science and Engineering, Meijo University, Nagoya 468-8502 (Japan); Kikegawa, T [Photon Factory (PF), Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan)], E-mail: NAKANO.Satoshi@nims.go.jp

    2008-07-15

    Lithium borohydride (LiBH{sub 4}) was compressed up to 10 GPa using a diamond-anvil-cell to investigate its high-pressure structure. In-situ x-ray diffraction profiles indicated a pressure-induced transformation at 1.1 GPa, which was consistent with the previous experimental observation such as Raman scattering spectroscopy. The high-pressure phase was indexed on a tetragonal symmetry of P4{sub 2}/mmc, which was not corresponding some structural models proposed by previous calculation studies. An unknown substance (presumably another Li-B-H compound), which was contained in the starting material, also transformed into its high-pressure phase at 0.6 GPa without any relation to the transformation of LiBH{sub 4}.

  4. Early bilateral radiation-induced optic neuropathy with follow-up MRI

    International Nuclear Information System (INIS)

    McClellan, R.L.; El Gammal, T.; Kline, L.B.

    1995-01-01

    Most documented cases of radiation-induced optic neuropathy are unilateral and occur more than 1 year after radiotherapy to the sellar region. We describe a patient with bilateral radiation optic neuropathy 3 months following the completion of radiotherapy. MRI 13 months after the onset of visual failure showed bilateral optic atrophy with residual gadolinium enhancement. (orig.)

  5. Early bilateral radiation-induced optic neuropathy with follow-up MRI

    Energy Technology Data Exchange (ETDEWEB)

    McClellan, R.L. [Alabama Univ., Birmingham (United States). Dept. of Radiology; El Gammal, T. [Alabama Univ., Birmingham (United States). Dept. of Radiology; Kline, L.B. [Alabama Univ., Birmingham (United States). Dept. of Radiology

    1995-02-01

    Most documented cases of radiation-induced optic neuropathy are unilateral and occur more than 1 year after radiotherapy to the sellar region. We describe a patient with bilateral radiation optic neuropathy 3 months following the completion of radiotherapy. MRI 13 months after the onset of visual failure showed bilateral optic atrophy with residual gadolinium enhancement. (orig.)

  6. Comparison of the visual and intraocular optical performance of a refractive multifocal IOL with rotational asymmetry and an apodized diffractive multifocal IOL.

    Science.gov (United States)

    Alió, Jorge L; Plaza-Puche, Ana B; Javaloy, Jaime; Ayala, María José

    2012-02-01

    To compare the visual outcomes and intraocular optical quality observed postoperatively in patients implanted with a rotationally asymmetric multifocal intraocular lens (IOL) and an apodized diffractive multifocal IOL. Seventy-four consecutive eyes of 40 cataract patients (age range: 36 to 79 years) were divided into two groups: zonal refractive group, 39 eyes implanted with a rotationally asymmetric multifocal IOL (Lentis Mplus LS-312 IOL, Oculentis GmbH); and diffractive group, 35 eyes implanted with an apodized diffractive multifocal IOL (ReSTOR SN6AD3, Alcon Laboratories Inc). Distance and near visual acuity outcomes, contrast sensitivity, intraocular optical quality, and defocus curves were evaluated during 3-month follow-up. Calculation of the intraocular aberrations was performed by subtracting corneal aberrations from total ocular aberrations. Uncorrected near visual acuity and distance-corrected near visual acuity were better in the diffractive group than in the zonal refractive group (P=.01), whereas intermediate visual acuity (defocus +1.00 and +1.50 diopters) was better in the zonal refractive group. Photopic contrast sensitivity was significantly better in the zonal refractive group (P=.04). Wavefront aberrations (total, higher order, tilt, primary coma) were significantly higher in the zonal refractive group than in the diffractive group (P=.02). Both multifocal IOLs are able to successfully restore visual function after cataract surgery. The zonal refractive multifocal IOL provides better results in contrast sensitivity and intermediate vision, whereas the diffractive multifocal IOL provides better near vision at a closer distance. Copyright 2012, SLACK Incorporated.

  7. Evaluation of acute radiation optic neuropathy by B-scan ultrasonography

    International Nuclear Information System (INIS)

    Lovato, A.A.; Char, D.H.; Quivey, J.M.; Castro, J.R.

    1990-01-01

    We studied the accuracy of B-scan ultrasonography to diagnose radiation-induced optic neuropathy in 15 patients with uveal melanoma. Optic neuropathy was diagnosed by an observer masked as to clinical and photographic data. We analyzed planimetry area measurements of the retrobulbar nerve before and after irradiation. The retrobulbar area of the optic nerve shadow on B-scan was quantitated with a sonic digitizer. Increased optic nerve shadow area was confirmed in 13 of 15 patients who had radiation optic neuropathy (P less than .004). The correct diagnosis was confirmed when the results of ultrasound were compared to fundus photography and fluorescein angiography. In 13 patients there was acute radiation optic neuropathy. Two patients did not show an enlarged retrobulbar optic nerve, and the clinical appearance suggested early progression to optic atrophy. Ultrasonography documents the enlargement of the optic nerve caused by acute radiation changes

  8. Copper Vapor Laser with One-Beam Radiation of Diffraction Quality and Its Capabilities for Microprocessing of Materials for Electronic Engineering Products

    Directory of Open Access Journals (Sweden)

    N. A. Lyabin

    2014-01-01

    Full Text Available The structure, spatial, time and energy characteristics of copper vapor laser radiation (CVL with optical resonators possessing high spatial selectivity have been investigated: with an unstable resonator (UR with two convex mirrors and telescopic UR, and the conditions to form one-beam radiation with diffraction divergence and high stability of directivity pattern axis have been defined.The most weighty and prospective application of CVL with UR with two convex mirrors is to use it as a driving oscillator (DO in a copper vapor laser system (CVLS of the type: driving oscillator – power amplifier (DO – PA when diffraction beam radiating power and power density in a focused spot of 10-20 µm in diameter increases by 1-2 orders. Using industrial sealed-off active elements (AE of “Kulon” series with an average radiation power of 15-25 W as PAs the peak power density increases up to 1011 W/cm 2 while an application of AE “Crystal” with 30- 50 W power gives up to 1012 W/cm 2 , which is sufficient for efficient and qualitative microprocessing of materials up to 1…2 mm thick. Such a CVLS has become the basis for creating up-to-date automated laser technological installations (ALTI of “Karavella-1” and “Karavella-1M” types to manufacture precision parts of electronic engineering products (EEP of metal up to 0.5 mm thick and of non-metal up to 1.5…1.8 mm thick.CVL with a telescopic UR with an average power of 5-6 W diffraction radiation beam has become the basis for creating industrial ALTI “Karavella-2” and “Karavella-2M” to manufacture precision parts of electronic engineering products (EEP of metal up to 0.3 mm thick and of non-metal up to 0.5 – 0.7 mm thick.Practical work on all types of ALTI “Karavella” has shown a set of significant advantages of a laser way of pulsed microprocessing over the traditional ones, including electro-erosion machining: a wide range of structural metal and non-metal materials to be

  9. The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

    Science.gov (United States)

    Schäfers, F.; Bischoff, P.; Eggenstein, F.; Erko, A.; Gaupp, A.; Künstner, S.; Mast, M.; Schmidt, J.-S.; Senf, F.; Siewert, F.; Sokolov, A.; Zeschke, Th.

    2016-01-01

    A technology center for the production of high-precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at-wavelength characterization of UV- and XUV-reflection gratings and other (nano-) optical elements has been set up at BESSY-II. The Plane Grating Monochromator beamline operated in collimated light (c-PGM) is equipped with an SX700 monochromator, of which the blazed gratings (600 and 1200 lines mm−1) have been recently exchanged for new ones of improved performance produced in-house. Over the operating range from 10 to 2000 eV this beamline has very high spectral purity achieved by (i) a four-mirror arrangement of different coatings which can be inserted into the beam at different angles and (ii) by absorber filters for high-order suppression. Stray light and scattered radiation is removed efficiently by double sets of in situ exchangeable apertures and slits. By use of in- and off-plane bending-magnet radiation the beamline can be adjusted to either linear or elliptical polarization. One of the main features of a novel 11-axes reflectometer is the possibility to incorporate real life-sized gratings. The samples are adjustable within six degrees of freedom by a newly developed UHV-tripod system carrying a load up to 4 kg, and the reflectivity can be measured between 0 and 90° incidence angle for both s- and p-polarization geometry. This novel powerful metrology facility has gone into operation recently and is now open for external users. First results on optical performance and measurements on multilayer gratings will be presented here. PMID:26698047

  10. Diffraction of a Gaussian beam in a three-dimensional smoothly inhomogeneous medium: an eikonal-based complex geometrical-optics approach.

    Science.gov (United States)

    Berczynski, Pawel; Bliokh, Konstantin Yu; Kravtsov, Yuri A; Stateczny, Andrzej

    2006-06-01

    We present an ab initio account of the paraxial complex geometrical optics (CGO) in application to scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of the Riccati type. This substantially simplifies the description of Gaussian beam diffraction as compared with full-wave or parabolic (quasi-optics) equations. For a Gaussian beam propagating in a homogeneous medium or along the symmetry axis in a lenslike medium, the CGO equations possess analytical solutions; otherwise, they can be readily solved numerically. As a nontrivial example we consider Gaussian beam propagation and diffraction along a helical ray in an axially symmetric waveguide medium. It is shown that the major axis of the beam's elliptical cross section grows unboundedly; it is oriented predominantly in the azimuthal (binormal) direction and does not obey the parallel-transport law.

  11. Measurement of grain size of polycrystalline materials with confocal energy dispersive micro-X-ray diffraction technology based on polycapillary X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Weiyuan; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Peng, Song [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Li, Fangzuo; Sun, Xuepeng; Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2014-11-11

    The confocal energy dispersive micro-X-ray diffraction (EDMXRD) based on polycapillary X-ray optics was used to determine the grain size of polycrystalline materials. The grain size of a metallographic specimen of nickel base alloy was measured by using the confocal EDMXRD. The experimental results demonstrated that the confocal EDMXRD had potential applications in measuring large grain size.

  12. How to obtain traceability on optical radiation measurements?

    Science.gov (United States)

    Matamoros García, Carlos H.

    2006-02-01

    Traceability to national standards provides confidence in measurements results, granting a guaranty when carrying out governmental rules and when demonstrating conformity with quality requirements such as ISO 9000 or ISO/IEC 17025 (and the Mexican equivalent standards). The appropriate traceability contributes with confidence of the quality of products or services. This paper presents different ways to obtain traceability in Mexico for the optical radiation measurements, mentioning some applications, and highlighting the necessity of having traceability to the appropriate units of the SI. Additionally it present the national standards maintained by Centro Nacional de Metrologia (CENAM), the national metrology institute in Mexico, that give the technical support to Mexican measurements in this field and the international recognition that the personal of the Optics and Radiometry Division had gained in 10 years of development.

  13. Cloud-radiation interactions - Effects of cirrus optical thickness feedbacks

    Science.gov (United States)

    Somerville, Richard C. J.; Iacobellis, Sam

    1987-01-01

    The paper is concerned with a cloud-radiation feedback mechanism which may be an important component of the climate changes expected from increased atmospheric concentrations of carbon dioxide and other trace greenhouse gases. A major result of the study is that cirrus cloud optical thickness feedbacks may indeed tend to increase the surface warming due to trace gas increases. However, the positive feedback from cirrus appears to be generally weaker than the negative effects due to lower clouds. The results just confirm those of earlier research indicating that the net effect of cloud optical thickness feedbacks may be a negative feedback which may substantially (by a factor of about 2) reduce the surface warming due to the doubling of CO2, even in the presence of cirrus clouds.

  14. Hydration process for calcium-aluminate cement within EVA emulsion by SPring-8 synchrotron radiation x-ray diffraction method

    International Nuclear Information System (INIS)

    Kotera, Masaru; Matsuda, Ikuyo; Miyashita, Keiko; Adachi, Nobuyuki; Tamura, Hisayuki

    2005-01-01

    Polymer-modified mortars which consist of a polymer emulsion and cement materials have been widely developed in the construction materials fields. Forming process of the polymer-modified cement membrane simultaneously involves evaporation of water within the polymer emulsion and hydration of cement. It is important for the polymer-modified cement paste that the hydrate crystal of cement is generating by the hydration during the setting process under existence of the polymer emulsion. In this study, hydration process for calcium-aluminate cement under existence of poly (ethylene-vinyl acetate) (EVA) emulsion (polymer-cement ratio=100%) was investigated by X-ray diffraction method using synchrotron radiation (SPring-8). The diffraction peaks of calcium aluminate (CA) disappeared after the hardening, on the other hand, the peaks of hydrate crystals of calcium-aluminate cement (C 2 AH 8 and C 3 AH 6 ) could be observed. This polymer-modified cement paste hydrated using the water within the polymer emulsion. The hydration of C 2 AH 8 from CA started at around 300 min, and then C 3 AH 6 hydrate crystal increased after 700 min at ambient temperature. This implies that the conversion from C 2 AH 8 to C 3 AH 6 occurred to be more stable phase. The setting temperature affected the reaction rate. In case of hydration at 35degC, the start time of the hydration for calcium-aluminate cement was quicker than that in the ambient temperature four or more times. (author)

  15. A X-ray diffraction analysis on constituent distribution of heavy rust layer formed on weathering steel using synchrotron radiation

    International Nuclear Information System (INIS)

    Hara, Shuichi

    2008-01-01

    A local structural analysis of heavy rust layers with large swelling and laminated layers formed on weathering steel bridges using synchrotron radiation X-ray diffraction (SR-XRD) in SPring-8 have been performed. The main constituent in average composition of the whole layer was spinel-type iron oxide [mainly Magnetite (Fe 3 O 4 )] and the mass ratio was 30-40 mass%. In contrast the mass ratio of spinel in its local parts, i.e., outer layer, inter-layer and inner layer position was not higher in common but the mass ratio of β-FeOOH was higher. Therefore it indicates that these heavy rust layers have been composed of many layers of spinel poor, rich and poor - cell (SPRaP-cell). Thus SR-XRD is useful for the analysis of the constituent distribution in the rust layer. (author)

  16. X-ray diffraction analysis of rust layer on a weathering steel bridge with surface treatment using synchrotron radiation

    International Nuclear Information System (INIS)

    Yamashita, Masato; Hara, Shuichi; Kamimura, Takayuki; Miyuki, Hideaki; Sato, Masugu

    2007-01-01

    We have examined the structure of rust layer formed on a weathering steel bridge, to which the surface treatment, employing the effect of Cr 2 (SO 4 ) 3 sophisticatedly designed to form the protective goethite (α-FeOOH) rust layer which contains a certain amount of Cr, Cr-goethite, was applied in 1996, using X-ray diffraction at SPring-8 synchrotron radiation facility. It was shown that the formation of α-FeOOH was promoted and/or crystal growth of γ-FeOOH was suppressed by the surface treatment. The increase in the protective ability index (PAI) of the rust layer indicates that the protective goethite was predominantly formed under the effect of the surface treatment. In conclusion, it can be said that the surface treatment worked well to promote the formation of the protective goethite rust layer on the weathering steel bridge during the 10-year exposure. (author)

  17. Optical remote diagnostics of atmospheric propagating beams of ionizing radiation

    Science.gov (United States)

    Karl JR., Robert R.

    1990-03-06

    Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.

  18. [Occupational risk related to optical radiation exposure in construction workers].

    Science.gov (United States)

    Gobba, F; Modenese, A

    2012-01-01

    Optical Radiation is a relevant occupational risk in construction workers, mainly as a consequence of the exposure to the ultraviolet (UV) component of solar radiation (SR). Available data show that UV occupational limits are frequently exceeded in these workers, resulting in an increased occupational risk of various acute and chronic effects, mainly to skin and to the eye. One of the foremost is the carcinogenic effect: SR is indeed included in Group 1 IARC (carcinogenic to humans). UV exposure is related to an increase of the incidence of basal cell carcinoma, squamous cell carcinoma of the skin and cutaneous malignant melanoma (CMM). The incidence of these tumors, especially CMM, is constantly increasing in Caucasians in the last 50 years. As a conclusion, an adequate evaluation of the occupational risk related to SR, and adequate preventive measures are essential in construction workers. The role of occupational physicians in prevention is fundamental.

  19. Development of a silicon microstrip detector with single photon sensitivity for fast dynamic diffraction experiments at a synchrotron radiation beam

    Science.gov (United States)

    Arakcheev, A.; Aulchenko, V.; Kudashkin, D.; Shekhtman, L.; Tolochko, B.; Zhulanov, V.

    2017-06-01

    Time-resolved experiments on the diffraction of synchrotron radiation (SR) from crystalline materials provide information on the evolution of a material structure after a heat, electron beam or plasma interaction with a sample under study. Changes in the material structure happen within a microsecond scale and a detector with corresponding parameters is needed. The SR channel 8 of the VEPP-4M storage ring provides radiation from the 7-pole wiggler that allows to reach several tens photons within one μs from a tungsten crystal for the most intensive diffraction peak. In order to perform experiments that allow to measure the evolution of tungsten crystalline structure under the impact of powerful laser beam, a new detector is developed, that can provide information about the distribution of a scattered SR flux in space and its evolution in time at a microsecond scale. The detector is based on the silicon p-in-n microstrip sensor with DC-coupled metal strips. The sensor contains 1024 30 mm long strips with a 50 μm pitch. 64 strips are bonded to the front-end electronics based on APC128 ASICs. The APC128 ASIC contains 128 channels that consist of a low noise integrator with 32 analogue memory cells each. The integrator equivalent noise charge is about 2000 electrons and thus the signal from individual photons with energy above 40 keV can be observed. The signal can be stored at the analogue memory with 10 MHz rate. The first measurements with the beam scattered from a tungsten crystal with energy near 60 keV demonstrated the capability of this prototype to observe the spatial distribution of the photon flux with the intensity from below one photon per channel up to 0~10 photons per channel with a frame rate from 10 kHz up to 1 MHz.

  20. Phase and Chemical Composition Analysis on Neolithic Painted Ceramics Sherds Using Synchrotron Radiation X-Ray Powder Diffraction (SRXPD)

    International Nuclear Information System (INIS)

    Constantinescu, B.

    2003-01-01

    Full text: Synchrotron Radiation X-ray Powder Diffraction studies were performed at the wiggler beamline 1711 of MAX II Synchrotron accelerator from Lund, Sweden, in the frame of EU FPV Access to Large Scale Facilities programme. Diffraction data were collected using radiation of wavelength 1.36 A, which was detected by a Brucker system with a Smart 1000 CCD detector. The main goal of our studies was to distinguish different clays and mineral pigments of various Neolithic pottery-producing centres on Romanian territory in relation with possible inter-regional trade route connections. As main results we can mention: - identification of black pigment composition from Cucuteni (Northern Moldavia), Ariusd (South-Eastern Transylvania) and Cris-Starcevo (Oltenia) type pottery (VI - IV Millennia B. Chr.) as a combination of jacobsite, bixbyite (Manganese oxides), magnetite and goethite (Iron oxides) originary from North Moldova mineral deposits of Iacobeni (150 km up on the river Bistritza from analyzed Cucuteni archaeological sites), and as a combination of pyrolusite, magnetite and hematite for Cris-Starcevo samples, probably from local clay (enriched in Mn-Fe oxides) - identification of white pigment composition as calcite (CaCO3) for Cris- Starcevo culture sites from Central Transylvania (from the local abundant chalk deposits) and as calcium silicates mixed with illite (K, H2))Al2[(H2O, OH)2]AlSi3O10 for Cucuteni culture sites - identification of read-brown pigment composition as various mixtures of hematite - goethite - magnetite, all of local provenance - identification of all examined sherds as having local provenance for the clay The main conclusion is that during Neolithic period, the pottery workshops, largely extended on Romanian territory, used local clays but traded black mineral pigments across the Carpathian mountains (Cucuteni and Ariusd areas are separated by these mountains by easily crossed by passes along small rivers)

  1. Passive radiation detection using optically active CMOS sensors

    Science.gov (United States)

    Dosiek, Luke; Schalk, Patrick D.

    2013-05-01

    Recently, there have been a number of small-scale and hobbyist successes in employing commodity CMOS-based camera sensors for radiation detection. For example, several smartphone applications initially developed for use in areas near the Fukushima nuclear disaster are capable of detecting radiation using a cell phone camera, provided opaque tape is placed over the lens. In all current useful implementations, it is required that the sensor not be exposed to visible light. We seek to build a system that does not have this restriction. While building such a system would require sophisticated signal processing, it would nevertheless provide great benefits. In addition to fulfilling their primary function of image capture, cameras would also be able to detect unknown radiation sources even when the danger is considered to be low or non-existent. By experimentally profiling the image artifacts generated by gamma ray and β particle impacts, algorithms are developed to identify the unique features of radiation exposure, while discarding optical interaction and thermal noise effects. Preliminary results focus on achieving this goal in a laboratory setting, without regard to integration time or computational complexity. However, future work will seek to address these additional issues.

  2. Evaluation of a digital optical ionizing radiation particle track detector

    International Nuclear Information System (INIS)

    Hunter, S.R.

    1987-06-01

    An ionizing radiation particle track detector is outlined which can, in principle, determine the three-dimensional spatial distribution of all the secondary electrons produced by the passage of ionizing radiation through a low-pressure (0.1 to 10 kPa) gas. The electrons in the particle track are excited by the presence of a high-frequency AC electric field, and two digital cameras image the optical radiation produced in electronic excitation collisions of the surroundings gas by the electrons. The specific requirements of the detector for neutron dosimetry and microdosimetry are outlined (i.e., operating conditions of the digital cameras, high voltage fields, gas mixtures, etc.) along with an estimate of the resolution and sensitivity achievable with this technique. The proposed detector is shown to compare favorable with other methods for obtaining the details of the track structure, particularly in the quality of the information obtainable about the particle track and the comparative simplicity and adaptability of the detector for measuring the secondary electron track structure for many forms of ionizing radiation over a wide range of energies

  3. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  4. Tuning optical radiation for visual and nonvisual impact

    Science.gov (United States)

    Royer, Michael P.

    2011-12-01

    Spectral tuning---the allocation of radiant energy emitted by a lamp---is a fundamental element of illuminating engineering. Proper placement of optical radiation allows for reduced energy consumption, increased brightness perception, and improved color rendition. It can also result in lamps that have a greater impact on nonvisual human functions such as circadian rhythms, sleep, mood, and cognition. For an architectural lighting system, careful consideration must be given to all of these areas; recent advancements in understanding nonvisual photoreception must be balanced with the traditional emphasis on visual quality and energy efficiency. The three research projects described herein investigated spectral tuning by examining the effects of optical radiation or seeking ideal spectral power distributions. In all three cases, emphasis was placed on developing an architectural lighting system based on red, green, and blue (RGB) light emitting diodes (LEDs) that is capable of providing maximum stimulation to nonvisual systems while maintaining visual quality standards. In particular, the elderly were considered as a target population because they have an increased risk of developing disorders linked to illumination deficits. The three endeavors can be summarized as follows: Light Therapy for Seniors in Long-term Care AIM: To examine the effect of optical radiation on circadian rhythms, sleep, mood, and cognition for frail elderly in a long-term care environment. METHODOLOGY: A double-blind, placebo-controlled clinical trial of light therapy was conducted using circadian-effective short-wavelength (blue) optical radiation to treat a sample of residents recruited for participation without bias for existing medical diagnoses. KEY FINDINGS: Light therapy treatment improved cognitive functioning compared to placebo but no changes were detected in nighttime sleep statistics, reports of daytime sleepiness, circadian rhythms, or depression inventory parameters. Perceived

  5. Self-diffraction of continuous laser radiation in a disperse medium with absorbing particles

    DEFF Research Database (Denmark)

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

    2013-01-01

    We study the self-action of light in a water suspension of absorbing subwavelength particles. Due to efficient accumulation of the light energy, this medium shows distinct non-linear properties even at moderate radiation power. In particular, by means of interference of two obliquely incident beams...... formation is shown to be thermal, which leads to the phase grating; a weak amplitude grating also emerges due to the particles' displacements caused by the light-induced gradient and photophoretic forces. These forces, together with the Brownian motion of the particles, are responsible for the grating...

  6. Study of optically stimulated luminescence (OSL) for radiation detection. Application to an optical fibre γ-radiation sensor

    International Nuclear Information System (INIS)

    Roy, O.

    1998-01-01

    This work shows up the usefulness of the Optically Stimulated Luminescence (OSL) to resolve radioprotection problems. We study the use of OSL as a gamma dosimetric technique with respect to the ALARA's concept (As Low As Reasonably Achievable). A new approach based on optical fibers and luminescent materials showing OSL properties (closely related to Thermoluminescence phenomena) is presented in order to improve the remote real time dosimetry monitoring. Like thermoluminescent materials (TLD), OSL materials can trap charges under an irradiation (UV, X, γ,...). Instead of heating, the charges trapped are released by light stimulation and produce a visible luminescence which amount is proportional to trap the 'data stored' left by irradiation, enabling the dose measurement. The OSL phenomenon offers the same advantages as TLD plus the interesting possibility of a remote optical stimulation. The end-user objective deals with the development of a γ-radiation Optical FIber Sensor (OFS) for dose measurement which can offer new functionalities based on OSL materials coupled with an optical fiber. Rare earth doped Alkaline Earth Sulphides (AES), BAFX:EU 2+ (X = Cl, Br, I) and halogen alkaline have been studied (crystalline form, synthesis techniques, influence of dopants and color centers). Their characteristics are presented and extensively discussed. A specific experimental set-up to characterise various OSL phosphors has been developed. It allows the study of sensitivity, linearity, time decay behaviour of OSL signal and zeroing time. A joint study of OSL and TL has shown the technical limitations as well as the thermal fading and the origin of the long zeroing time. An Optical Fiber Sensor (OFS) based on OSL and using MgS:Sm has been developed for practical applications on nuclear fields. Its specifications are presented and discussed, moreover improvements are proposed. (author)

  7. Real-time synchrotoron radiation X-ray diffraction and abnormal temperature dependence of photoluminescence from erbium silicates on SiO2/Si substrates

    Directory of Open Access Journals (Sweden)

    H. Omi

    2012-03-01

    Full Text Available The erbium silicate formation processes during annealing in Ar gas were monitored by synchrotron radiation grazing incidence X-ray diffraction (GIXD in real time and the optical properties of the silicates were investigated by photoluminescence measurements in spectral and time-resolved domains. The GIXD measurements show that erbium silicates and erbium oxide are formed by interface reactions between silicon oxide and erbium oxides deposited on silicon oxide by reactive sputtering in Ar gas and O2/Ar mixture gas ambiences. The erbium silicates are formed above 1060 °C in Ar gas ambience and above 1010 °C in O2/Ar gas ambience, and erbium silicides are dominantly formed above 1250 °C. The I15/2-I13/2 Er3+ photoluminescence from the erbium oxide and erbium silicate exhibits abnormal temperature dependence, which can be explained by the phonon-assisted resonant absorption of the 532-nm excitation photons into the 2H11/2 levels of Er3+ ions of the erbium compounds.

  8. Optical characterization of OLED emitter properties by radiation pattern analyses

    Energy Technology Data Exchange (ETDEWEB)

    Flaemmich, Michael

    2011-09-08

    Researches in both, academia and industry are investigating optical loss channels in OLED layered systems by means of optical simulation tools in order to derive promising concepts for a further enhancement of the overall device performance. Besides other factors, the prospects of success of such optimization strategies rely severely on the credibility of the optical input data. The present thesis provides a guideline to measure the active optical properties of OLED emitter materials in situ by radiation pattern analyses. Reliable and widely applicable methods are introduced to determine the internal electroluminescence spectrum, the profile of the emission zone, the dipole emitter orientation, and the internal luminescence quantum efficiency of emissive materials from the optical far field emission of OLEDs in electrical operation. The proposed characterization procedures are applied to sets of OLEDs containing both, fluorescent polymeric materials as well as phosphorescent small-molecular emitters, respectively. On the one hand, quite expected results are obtained. On the other hand, several novel and truly surprising results are found. Most importantly, this thesis contains the first report of a non-isotropic, mainly parallel emitter orientation in a phosphorescent small-molecular guest-host system (Ir(MDQ)2(acac) in a-NPD). Due to the latter result, emitter orientation based optimization of phosphorescent OLEDs seems to be within reach. Since parallel dipoles emit preferably into air, the utilization of smart emissive materials with advantageous molecular orientation is capable to boost the efficiency of phosphorescent OLEDs by 50%. Materials design, the influence of the matrix material and the substrate, as well as film deposition conditions are just a few parameters that need to be studied further in order to exploit the huge potential of the dipole emitter orientation in phosphorescent OLEDs.

  9. Analysis of the selected optical parameters of filters protecting against hazardous infrared radiation

    OpenAIRE

    Gralewicz, Grzegorz; Owczarek, Grzegorz

    2016-01-01

    The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filters provide more effective blocking of infrared radiation in comparison with the currently used protec...

  10. Evaluation of optical fibres as gamma radiation dosimeter

    International Nuclear Information System (INIS)

    Bohra, Dinesh; Chaudhary, H.S.; Panwar, Lalit; Vaijapurkar, S.G.; Bhatnagar, P.K.; Dasgupta, K.

    2005-01-01

    Semiconductor base gamma and neutron sensors are the fastest and popular dosimeters and are in competition with Thermoluminescence (TL) and Radio photoluminescence (RPL) dosimeters. All over the world armed forces require a dosimeter which records cumulative doses of ionizing radiations from mcGy to 10 Gy and is readable repeatedly without loss of dose information. TL dosimeters do not meet the criteria and RPL dosimeter meet the expectations and are in use by armed forces. Technologists have used laser as an excitation source to stimulate the glass and have achieved success in recording gamma doses of occupational/accidental span (mcGy to 10 Gy). However synthesizing RPL glass batches with exactly same characteristics predoses is a difficult task. Silicon base phosphorous doped step index multimode optical fibre can be made in a significant quantity and large number of dosimeters from it can be achieved with uniform predose. The radiation induced transmission loss gives a measure of gamma dose which is cumulative, readable repeatedly without loss of information. Assorted composition, core dia optical fibres have been synthesized and evaluated for dose linearity, dose rate independence, fading, length optimization. Here in is described some results of recent experiments and sensitivities achieved. (author)

  11. Fibre optics compatibility with radiative environment inside PWR containment

    International Nuclear Information System (INIS)

    Breuze, G.; Jucker, P.; Serre, J.

    1993-01-01

    Fibre optic links operating with multiplexed sensors data are potentially attractive for nuclear power plant applications. It hence became essential to test for radiation vulnerability not only transmission support -fibres- but also fibre-end electro-optical components which could be exposed to hostile environment, perhaps in worse conditions than fibres. Present paper gives results of multimode silica-based fibre behaviour during long-term steady-state low dose-rate gamma ray exposure - one year under 0.1 to 0.2 Gy/h. Studies concerned radiation-induced loss (ΔL) measurement of eight different commercially available fibres and bit error-rate (BER) recording of four 1 100 m length data links operating with a 100 m part exposed to gamma-rays. Main result is the good behaviour of pure silica-core fibres, especially a step-index polymer-clad fibre transmitting 850 nm light but also a graded-index fluorine-clad fibre for 1 300 nm window. Mean ΔL values are respectively 3 dB/km and 4.5 dB/km at the exposure end. Complementary result is no influence of gamma-ray exposure upon data link initial 10 -9 BER. (authors). 9 figs., 7 tabs., 26 refs

  12. Optical Protection Filters for Harmful Laser Beams and UV Radiation

    Science.gov (United States)

    Azim M., Osama A.

    2007-02-01

    Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a `real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A.

  13. Optical Protection Filters for Harmful Laser Beams and UV Radiation

    International Nuclear Information System (INIS)

    Azim M, Osama A.

    2007-01-01

    Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a 'real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A

  14. Assessment of personal exposures to optical radiation in large entertainment venues

    International Nuclear Information System (INIS)

    Bonner, R.; O'Hagan, J. B.; Khazova, M.

    2012-01-01

    Workplace exposure to optical radiation from artificial sources is regulated in Europe under the Artificial Optical Radiation Directive 2006/25/EC implemented in the UK as The Control of Artificial Optical Radiation at Work Regulations 2010. The entertainment environment often presents an extremely complex situation for the assessment of occupational exposures. Multiple illumination sources, continuously changing illumination conditions and people moving during performances add further complexity to the assessment. This document proposes a methodology for assessing the risks arising from exposure to optical radiation and presents detailed case studies of practical assessment for two large entertainment venues. (authors)

  15. Evaluation of material dispersion using a nanosecond optical pulse radiator.

    Science.gov (United States)

    Horiguchi, M; Ohmori, Y; Miya, T

    1979-07-01

    To study the material dispersion effects on graded-index fibers, a method for measuring the material dispersion in optical glass fibers has been developed. Nanosecond pulses in the 0.5-1.7-microm region are generated by a nanosecond optical pulse radiator and grating monochromator. These pulses are injected into a GeO(2)-P(2)0(5)-doped silica graded-index fiber. Relative time delay changes between different wavelengths are used to determine material dispersion, core glass refractive index, material group index, and optimum profile parameter of the graded-index fiber. From the measured data, the optimum profile parameter on the GeO(2)-P(2)O(5)-doped silica graded-index fiber could be estimated to be 1.88 at 1.27 microm of the material dispersion free wavelength region and 1.82 at 1.55 microm of the lowest-loss wavelength region in silica-based optical fiber waveguides.

  16. Earth cloud, aerosol, and radiation explorer optical payload development status

    Science.gov (United States)

    Hélière, A.; Wallace, K.; Pereira do Carmo, J.; Lefebvre, A.

    2017-09-01

    The European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) are co-operating to develop as part of ESA's Living Planet Programme, the third Earth Explorer Core Mission, EarthCARE, with the ojective of improving the understanding of the processes involving clouds, aerosols and radiation in the Earth's atmosphere. EarthCARE payload consists of two active and two passive instruments: an ATmospheric LIDar (ATLID), a Cloud Profiling Radar (CPR), a Multi-Spectral Imager (MSI) and a Broad-Band Radiometer (BBR). The four instruments data are processed individually and in a synergetic manner to produce a large range of products, which include vertical profiles of aerosols, liquid water and ice, observations of cloud distribution and vertical motion within clouds, and will allow the retrieval of profiles of atmospheric radiative heating and cooling. MSI is a compact instrument with a 150 km swath providing 500 m pixel data in seven channels, whose retrieved data will give context to the active instrument measurements, as well as providing cloud and aerosol information. BBR measures reflected solar and emitted thermal radiation from the scene. Operating in the UV range at 355 nm, ATLID provides atmospheric echoes from ground to an altitude of 40 km. Thanks to a high spectral resolution filtering, the lidar is able to separate the relative contribution of aerosol and molecular scattering, which gives access to aerosol optical depth. Co-polarised and cross-polarised components of the Mie scattering contribution are measured on dedicated channels. This paper will provide a description of the optical payload implementation, the design and characterisation of the instruments.

  17. Hybrid formulation of radiation transport in optically thick divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rosato, J.; Marandet, Y.; Bufferand, H.; Stamm, R. [PIIM, UMR 7345 Aix-Marseille Universite / CNRS, Centre de St-Jerome, Marseille (France); Reiter, D. [IEK-4 Plasmaphysik, Forschungszentrum Juelich GmbH, Juelich (Germany)

    2016-08-15

    Kinetic Monte Carlo simulations of coupled atom-radiation transport in optically thick divertor plasmas can be computationally very demanding, in particular in ITER relevant conditions or even larger devices, e.g. for power plant divertor studies. At high (∝ 10{sup 15} cm{sup -3}) atomic densities, it can be shown that sufficiently large divertors behave in certain areas like a black body near the first resonance line of hydrogen (Lyman α). This suggests that, at least in part, the use of continuum model (radiation hydrodynamics) can be sufficiently accurate, while being less time consuming. In this work, we report on the development of a hybrid model devoted to switch automatically between a kinetic and a continuum description according to the plasma conditions. Calculations of the photo-excitation rate in a homogeneous slab are performed as an illustration. The outlined hybrid concept might be also applicable to neutral atom transport, due to mathematical analogy of transport equations for neutrals and radiation. (copyright 2016 The Authors. Contributions to Plasma Physics published by Wiley-VCH Verlag GmbH and Co. KGaA Weinheim. This)

  18. VCSEL-based radiation tolerant optical data links

    CERN Document Server

    Gregor, I M; Dowell, J; Jovanovic, P; Kootz, A; Mahout, G; Mandic, I; Weidberg, T

    2000-01-01

    The Large Hadron Collider (LHC) will become operational in 2005 at The European Laboratory for Particle Physics (CERN). The LHC will be the highest energy proton-proton collider in the world. One of the electronic particle detectors which will operate at the LHC is called ATLAS. The environment for electronics placed within ATLAS is extremely hostile due to the high levels of radiation and the general lack of access to components during the expected 10 year lifetime of the experiment. It is planned to use custom radiation tolerant VCSEL- based optical links to transfer data from the ATLAS inner detector to remote data acquisition electronics. A low mass, non-magnetic and radiation tolerant VCSEL packaging has been developed for the most hostile region in the center of ATLAS where the inner detector is located. The performance of the package is reported on. Qualification tests of commercial VCSELs are also described. The VCSELs were irradiated with neutrons (up to 8.10/sup 14/ n(1 MeV)/cm/sup 2/) and annealing...

  19. A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

    International Nuclear Information System (INIS)

    Liu Yanping; Du Yanzhao; Chen Zhaoyang; Ba Weizhen; Fan Yanwei; Pan Shilie; Guo Qi

    2008-01-01

    The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. (authors)

  20. System of laser pump and synchrotron radiation probe microdiffraction to investigate optical recording process

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Nobuhiro; Fukuyama, Yoshimitsu; Osawa, Hitoshi [Research and Utilization Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Kimura, Shigeru [Research and Utilization Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Ito, Kiminori; Tanaka, Yoshihito [RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Matsunaga, Toshiyuki; Kojima, Rie; Hisada, Kazuya; Tsuchino, Akio; Birukawa, Masahiro [R and D Division, Panasonic Corporation, 3-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan); Yamada, Noboru [Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, Kyoto 606-8501 (Japan); Sekiguchi, Koji; Fujiie, Kazuhiko; Kawakubo, Osamu [Advanced Optical Storage Development Department, Advanced Device Technology Platform, Sony Corporation, 4-14-1 Asahi-cho, Atsugi, Kanagawa 243-0014 (Japan); Takata, Masaki [Research and Utilization Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Department of Advanced Materials Science, School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)

    2013-06-15

    We have developed a system of laser-pump and synchrotron radiation probe microdiffraction to investigate the phase-change process on a nanosecond time scale of Ge{sub 2}Sb{sub 2}Te{sub 5} film embedded in multi-layer structures, which corresponds to real optical recording media. The measurements were achieved by combining (i) the pump-laser system with a pulse width of 300 ps, (ii) a highly brilliant focused microbeam with wide peak-energy width ({Delta}E/E {approx} 2%) made by focusing helical undulator radiation without monochromatization, and (iii) a precise sample rotation stage to make repetitive measurements. We successfully detected a very weak time-resolved diffraction signal by using this system from 100-nm-thick Ge{sub 2}Sb{sub 2}Te{sub 5} phase-change layers. This enabled us to find the dependence of the crystal-amorphous phase change process of the Ge{sub 2}Sb{sub 2}Te{sub 5} layers on laser power.

  1. In-situ Diffraction Study of Magnetite at Simultaneous High Pressure and High Temperature Using Synchrotron Radiation

    Science.gov (United States)

    Wang, L.; Zhang, J.; Wang, S.; Chen, H.; Zhao, Y.

    2014-12-01

    Magnetite intertwined with the evolution of human civilizations, and remains so today. It is technologically and scientifically important by virtue of its unique magnetic and electrical properties. Magnetite is a common mineral found in a variety of geologic environments, and plays an important role in deciphering the oxygen evolution in the Earth's atmosphere and its deep interiors. The latter application asks for the knowledge of the thermal and elastic properties of magnetite at high pressures and temperatures, which is currently not available in literature. We have carried out a few in-situ diffraction experiments on magnetite using white synchrotron radiation at beamline X17B2 of National Synchrotron Light Source (NSLS). A DIA module in an 1100-ton press and WC anvils were employed for compression, and diffraction spectra were collected at simultaneous high pressures (P) and temperatures (T) (up to 9 GPa and 900 oC). Mixture of amorphous boron and epoxy resin was used as pressure medium, and NaCl as pressure marker. Temperature was recorded by W-Re thermocouples. Commercially purchased magnetite powder and a mixture of the said powder and NaCl (1:1) were used as starting material in separate experiments. Preliminary data analyses have yielded following observations: (1) Charge disordering seen at ambient pressure remains active in current experiments, especially at lower pressures (reversibility and degree of cation disordering depend on the starting material and/or experimental P-T path; and (4) cation disordering notably reduces the apparent bulk moduli of magnetite.

  2. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  3. Powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Hart, M.

    1995-12-31

    the importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940`s, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments.

  4. Powder diffraction

    International Nuclear Information System (INIS)

    Hart, M.

    1995-01-01

    The importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940's, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments

  5. Applications of anomalous diffraction systems, generation of attosecond electron and photon pulses and Raman amplification by stimulated emission of radiation

    Science.gov (United States)

    Vartak, Sameer Dinkar

    1998-10-01

    Anomalous diffraction is scattering process due to phase distortion introduced on incident phase front by scattering object. Phase mask or hologram, Christiansen filter, PDLC are examples of an anomalously diffracting systems. Phase hologram modulates an input wavefront to produce a wavefront which when Fourier transformed using a converging lens gives desired image on to a screen. We made a nonlinear optical element using phase mask made up of nonlinear material. It forms a lens because of nonlinear index of refraction when a high intensity beam is incident. This lens Fourier transforms the phase mask and images the phase mask. This nonlinear optical element can be used for various applications like image gating and 3-D memory writing and read out. Christiansen filter (CF) is a two component scattering system whose dispersion curves intersect at certain wavelength. Thus light corresponding to this wavelength traverses the filter without any scattering and light at other wavelengths gets scattered. This results in narrow wavelength dependent transmission curve centered at the index matching wavelength. When materials with an intensity dependent refractive index are used to make a CF, the index matching condition of CF becomes function of the input intensity resulting in intensity dependent beam size and transmittance through the filter. This property of nonlinear CF can be used to switch beam optically in both self and cross-modulation modes. Polymer Dispersed Liquid Crystal (PDLC) is dispersion of liquid crystal droplets in polymer whose index of refraction is same as ordinary refractive index of liquid crystal. PDLC shows voltage dependent scattering and are used in flat panel displays. We used this element as voltage controlled intracavity loss element in a laser cavity to make a lasing pixel projection display. Output of this pixel shows all desired properties for a projection display like narrow linewidth, high brightness, TTL switching compatibility and

  6. Proposal for the development of ICNIRP guidelines on limits for optical radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Siekmann, H. [Berufsgenossenschaftliches Institut fuer Arbeitsschutz - FIA, Sankt Augustin (Germany); Reidenbach, H.D. [Fachhochschule Koeln (Germany)

    2004-07-01

    Guidelines on limits of exposure to incoherent ultraviolet radiation, to incoherent visible and infrared radiation and to laser radiation have been published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These guidelines are accepted globally and form the basis for risk assessment procedures for optical radiation in many countries. With the appearance of new scientific cognition the ICNIRP guidelines will be revised from time to time. A revision may also concern more formal aspects. Some proposals for the development of the ICNIRP limit value recommendations for optical radiation exposures follow. (orig.)

  7. X-ray diffraction study on the structure of concentrated aqueous solutions involving alanine molecules with different optical activities

    International Nuclear Information System (INIS)

    Kameda, Yasuo; Okuyama, Aya; Amo, Yuko; Usuki, Takeshi; Kohara, Shinji

    2007-01-01

    X-ray diffraction measurements on aqueous 2.5 mol% DL-, L-, and D-alanine solutions in D 2 O were carried out at 26±2degC in order to obtain information concerning the difference in the hydrogen-bonded structure between aqueous solutions involving amino acid molecules with different optical activities. The difference function, Δi inter (Q), between intermolecular interference term observed for DL- and L-alanine and between DL- and D-alanine solutions both exhibited a first peak at Q=1.6 A -1 , followed by oscillatory features extending to higher-Q region, implying that there is a difference in the intermolecular structure is present between these solutions. The difference distribution function, Δg inter (r), obtained from the Fourier transform of the Δi inter (Q) between DL- and L-, and between DL- and D-alanine solutions showed an obvious negative peak at r=2.8 A, which was attributed to the nearest neighbor hydrogen-bonded O...O interaction. The least squares fitting analysis of the observed Δi inter (Q) showed that the intermolecular O...O distance and the difference in the coordination number between DL- and L-, and between DL- and D-alanine solutions are 2.76(2) A and -0.18(1), and 2.81(3) A and -0.18(1), respectively. It was concluded that the intermolecular hydrogen-bonded network in aqueous L- and D-alanine solutions is stronger than that in the DL-alanine solution. (author)

  8. Optical Cherenkov radiation in ultrafast cascaded second-harmonic generation

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin

    2010-01-01

    -matching point is located in the absorption region of the crystal, effectively absorbing the generated dispersive wave. By calculating the phase-matching curves for typically used frequency conversion crystals, we point out that the mid-IR absorption in the crystal in many cases automatically will filter away....... The beating between the dispersive wave and the soliton generates trailing temporal oscillations on the compressed soliton. Insertion of a simple short-wave pass filter after the crystal can restore a clean soliton. On the other hand, bandpass filtering around the dispersive wave peak results in near......We show through theory and numerics that when few-cycle femtosecond solitons are generated through cascaded (phase-mismatched) second-harmonic generation, these broadband solitons can emit optical Cherenkov radiation in the form of linear dispersive waves located in the red part of the spectrum...

  9. Optical transition radiation interferometry for the A0 photoinjector

    International Nuclear Information System (INIS)

    Kazakevich, G.; Novosibirsk, IYF; Edwards, H.; Fliller, R.; Nagaitsev, S.; Ruan, J.; Thurman-Keup, R.; Fermilab

    2008-01-01

    Optical Transition Radiation Interferometry (OTRI) is a promising diagnostic technique and has been successfully developed and used for investigation of relativistic beams. For mid-energy accelerators the technique is traditionally based on thin polymer films (the first one is being transparent for visible light), which causes beam multiple scattering of about 1 mrad. A disadvantage of those films is unacceptable vacuum properties for photoinjectors and accelerators using superconducting cavities. We have studied the application of thin mica sheets for the OTRI diagnostics at the A0 Photoinjector in comparison with 2.5 (micro)m thick Mylar films. This diagnostic is also applicable for the ILCTA-NML accelerator test facility that is planned at Fermilab. This report discusses the experimental setups of the OTR interferometer for the A0 Photoinjector and presents comparisons of simulations and measurements obtained using Mylar and mica-based interferometers

  10. A general purpose fiber optic link with radiation resistance

    International Nuclear Information System (INIS)

    Beadle, E.R.

    1995-01-01

    In some applications it is necessary to send wide-band analog data, with good fidelity, between two stations separated by several hundred feet. This is particularly true for instrumentation in an accelerator environment, where the sensing equipment can be inside the tunnel, and the processing equipment outside. Aside from the distortion and loss introduced by low cost coaxial cables, this case is further complicated by the possibility of pick-up from environmental noise, and the possible radiation damage of the transmitting electronics. Fiber optics is be a viable alternative to the standard coaxial driver, particularly where video bandwidths are concerned. This paper discusses basic design, trade-offs, and performance of one such link developed primarily for the AGS-to-RHIC (ATR) Transfer line profile monitors

  11. Towards diffractive imaging with single pulses of FEL radiation. Dynamics within irradiatied samples and their influence on the analysis of imaging data

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fenglin

    2010-08-15

    3D single particle coherent diffraction imaging (CDI) of bioparticles (such as proteins, macromolecules and viruses) is one of the main possible applications of the new generation of light sources: free-electron lasers (FELs), which are now available at FLASH (Hamburg, Germany) and LCLS (Stanford, U.S.A.). The extremely bright and ultrashort FEL pulses potentially enable CDI to achieve high resolution down to subnanometer length scale. However, intense FEL pulses cause serious radiation damage in bioparticles, even during single shots, which may set the resolution limits for CDI with FELs. Currently, since the signal-to-noise ratio is very low for small biological particles, direct experimental study of radiation damage in the single particle imaging is fairly difficult. Single atomic (noble gas) clusters become good objects to reveal effects of radiation damage processes on CDI with FEL radiation. This thesis studies three aspects of the radiation damage problem, which are treated in three independent chapters: (1) Molecular Dynamics simulations to quantitively describe radiation damage processes within irradiated atomic clusters during single pulses; (2) reconstruction analysis of single-shot CDI diffraction patterns of atomic clusters, which may potentially help to understand the radiation damage occurring in biological samples; and (3) testing the effects of coating water layers in CDI, which is supposed to minimize the radiation damage in irradiated bioparticles. (orig.)

  12. On the formation of TW Crv optical radiation

    Science.gov (United States)

    Shimansky, V. V.; Mitrofanova, A. A.; Borisov, N. V.; Fabrika, S. N.; Galeev, A. I.

    2016-10-01

    We present the analysis of the optical radiation of the young pre-cataclysmic variable TW Crv. Spectroscopic and photometric observations were obtained at the SAO RAS 6-m BTA telescope and at the Russian-Turkish RTT-150 telescope. The light curves of the system posses nearly sinusoidal shapes with the amplitudes of Δ m > 0.m7, what is typical for young pre-cataclysmic variables with sdO-subdwarfs and orbit inclinations of less than 45◦. The optical spectrum contains dominant radiation of the hot subdwarf with the HI and He II absorption lines and strong emission lines, which are formed in the atmosphere of the secondary owing to the reflection effects. Radial velocities of the cool star were measured by analyzing the λλ 4630-4650 Å Bowen blend, which for the first time allowed to determine the component masses. A numerical simulation of the light curves and spectra of TW Crv, obtaining a complete set of systems fundamental parameters was carried out. The hot star parameters prompt its belonging to the sdOsubdwarf class at the stage of transition to the cooling white dwarf sequence. The absence of its observable planetary nebula is caused by a long-lasting evolution of the system after the common envelope state. The secondary component has a luminosity excess, which is typical for other young sdO-subdwarf precataclysmic variables. Its position on the " age-luminosity excess" diagram points at the accuracy of the obtained set of TW Crv fundamental parameters and at the similarity of its evolutionary and physical conditions with that of other BE UMa-type objects.

  13. Radiation-optical properties of the glasses for the space application

    International Nuclear Information System (INIS)

    Akishin, A.I.; Tseplyaev, L.I.

    2006-01-01

    The data are presented and generalized on variations of optical properties of glass and light guides under simulative cosmic ionizing radiation. It is shown that changes in optical properties (coloration, bleaching, opacity, luminescence) under ionizing radiation are associated with color centers formation and annealing [ru

  14. Multi Optical Transition Radiation System for ATF2

    International Nuclear Information System (INIS)

    Alabau-Gonzalvo, Javier

    2012-01-01

    In this paper we describe the design, installation and first calibration tests of a Multi Optical Transition Radiation System in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. This system will be a valuable tool for measuring beam sizes and emittances coming from the ATF Damping Ring. With an optical resolution of about 2 (micro)m an original OTR design (OTR1X) located after the septum at the entrance of the EXT line demonstrated the ability to measure a 5.5 (micro)m beam size in one beam pulse and to take many fast measurements. This gives the OTR the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter. Furthermore the nearby wire scanners will be a definitive test of the OTR as a beam emittance diagnostic device. The multi-OTR system design proposed here is based on the existing OTR1X.

  15. Optical response of thin amorphous films to infrared radiation

    Science.gov (United States)

    Orosco, J.; Coimbra, C. F. M.

    2018-03-01

    We briefly review the electrical-optical response of materials to radiative forcing within the formalism of the Kramers-Kronig relations. A commensurate set of criteria is described that must be met by any frequency-domain model representing the time-domain response of a real (i.e., physically possible) material. The criteria are applied to the Brendel-Bormann (BB) oscillator, a model that was originally introduced for its fidelity at reproducing the non-Lorentzian peak broadening experimentally observed in the infrared absorption by thin amorphous films but has since been used for many other common materials. We show that the BB model fails to satisfy the established physical criteria. Taking an alternative approach to the model derivation, a physically consistent model is proposed. This model provides the appropriate line-shape broadening for modeling the infrared optical response of thin amorphous films while adhering strictly to the Kramers-Kronig criteria. Experimental data for amorphous alumina (Al2O3 ) and amorphous quartz silica (SiO2) are used to obtain model parametrizations for both the noncausal BB model and the proposed causal model. The proposed model satisfies consistency criteria required by the underlying physics and reproduces the experimental data with better fidelity (and often with fewer parameters) than previously proposed permittivity models.

  16. Optical breakdown of helium in Bessel laser radiation beams

    International Nuclear Information System (INIS)

    Andreev, N E; Pleshanov, I V; Margolin, L Ya; Pyatnitskii, Lev N

    1998-01-01

    Numerical simulation is used to investigate the dynamics of formation of a helium plasma in Bessel beams, shaped by an axicon and a phase converter from a laser radiation pulse with Gaussian temporal and radial intensity profiles. The beam intensities at the breakdown threshold are determined as a function of the pulse duration for various radial field distributions in a beam characterised by Bessel functions of order m (m = 0 - 5). It is shown that in the investigated range of parameters the threshold intensity is independent of m. The temporal and spatial evolution of the resultant plasma, and the dependence of the plasma characteristics on the pulse parameters are considered. Conditions are found for the formation of tubular plasma channels in beams of orders m≥1. The adopted model of the optical breakdown of helium is shown to be satisfactory because of a good agreement between the results of calculations of the moment of breakdown in a zeroth-order Bessel beam and experimental results. (interaction of laser radiation with matter. laser plasma)

  17. X-ray diffraction using synchrotron radiation on the G.I.L.D.A. beam line at the E.S.R.F

    Energy Technology Data Exchange (ETDEWEB)

    Balerna, A [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Meneghini, C [INFN, Laboratori Nazionali di Frascati, Rome (Italy); [INFM, Genoa (Italy); Bordoni, S [Rome Univ. ` Tor Vergata` (Italy). Dip. di Fisica; Mobilio, S [Rome Univ. III (Italy). Dip. di Fisica ` E. Amaldi`

    1996-09-01

    The aim of this lecture is to make a short introduction on Synchrotron radiation, its history and main properties. The main components of a synchrotron radiation beam line will be described. The Italian beam line, General purpose Italian beam line Line for Diffraction and Absorption (G.I.L.D.A.) at the European Synchrotron Radiation Facility (E.S.R.F.) in Grenoble will be used as an example. The G.I.L.D.A. diffractometer will be described in detail reporting also some experimental results.

  18. The applicability of physical optics in the millimetre and sub-millimetre spectral region. Part I: The ray tracing with diffraction on facets method

    International Nuclear Information System (INIS)

    Baran, A.J.; Hesse, Evelyn; Sourdeval, Odran

    2017-01-01

    Future satellite missions, from 2022 onwards, will obtain near-global measurements of cirrus at microwave and sub-millimetre frequencies. To realise the potential of these observations, fast and accurate light-scattering methods are required to calculate scattered millimetre and sub-millimetre intensities from complex ice crystals. Here, the applicability of the ray tracing with diffraction on facets method (RTDF) in predicting the bulk scalar optical properties and phase functions of randomly oriented hexagonal ice columns and hexagonal ice aggregates at millimetre frequencies is investigated. The applicability of RTDF is shown to be acceptable down to size parameters of about 18, between the frequencies of 243 and 874 GHz. It is demonstrated that RTDF is generally well within about 10% of T-matrix solutions obtained for the scalar optical properties assuming hexagonal ice columns. Moreover, on replacing electromagnetic scalar optical property solutions obtained for the hexagonal ice aggregate with the RTDF counterparts at size parameter values of about 18 or greater, the bulk scalar optical properties can be calculated to generally well within ±5% of an electromagnetic-based database. The RTDF-derived bulk scalar optical properties result in brightness temperature errors to generally within about ±4 K at 874 GHz. Differing microphysics assumptions can easily exceed such errors. Similar findings are found for the bulk scattering phase functions. This finding is owing to the scattering solutions being dominated by the processes of diffraction and reflection, both being well described by RTDF. The impact of centimetre-sized complex ice crystals on interpreting cirrus polarisation measurements at sub-millimetre frequencies is discussed. - Highlights: • A method of physical optics is shown to apply to size parameters as low as 18 in the mm and sub-mm-wave spectral regions. • Including ray tracing with diffraction on facets and diffraction at the cross-section of

  19. Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

    Science.gov (United States)

    Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

    2017-07-01

    Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers.

  20. ALL-OPTICAL CONTROL OF THZ RADIATION IN PARALLEL PLATE WAVEGUIDES

    DEFF Research Database (Denmark)

    2010-01-01

    The invention relates to control of THz radiation in parallel plate waveguides (PPWG) by forming components in the waveguide by use of optical radiation pulses. Patterns of excited regions induced in the PPWG by an optical excitation pulses changes the electromagnetic properties of the waveguide...... medium in the THz regime, thereby forming transient passive and active components for controlling THz radiation signals. The excitation can be generation of free charge carriers in a semiconductor material in the PPWG, to create metallic regions that form mirrors, lenses or photonic crystal structures......-on-a-chip applications. The optical and THz radiation can be ultrashort pulses with picosecond or femtosecond pulse durations. L...

  1. The transition radiation. 2. experimental study of the optical transition radiation

    International Nuclear Information System (INIS)

    Couillaud, Ch.; Haouat, G.; Seguin, S.; Striby, S.

    1999-01-01

    Optical-transition-radiation-based diagnostics have been widely used for many years on electron accelerators in order to measure beam energy and transverse and longitudinal emittances. These diagnostics are very attractive for high brightness electron beams used as drivers for radiation sources. Such diagnostics have been performed on the ELSA facility (18 MeV electron energy, 100 A peak current) using both a single interface and an OTR-Wartski interferometer. We present the accelerator, the experimental set-up and the method for analyzing the OTR angular distribution. Then, the experimental results are described and compared with those from the three gradient method. In addition, we present a beam energy measurement using OTR interferogram analysis. (author)

  2. Nanofocusing of electromagnetic radiation

    DEFF Research Database (Denmark)

    Gramotnev, D. K.; Bozhevolnyi, Sergey I.

    2014-01-01

    Nanofocusing of electromagnetic radiation, that is, reducing the cross sections of propagating optical modes far beyond the diffraction limit in dielectric media, can be achieved in tapered metal-dielectric waveguides that support surface plasmon-polariton modes. Although the main principles...... radiation on the nanoscale. Here, we present the underlying physical principles of radiation nanofocusing in metallic nanostructures, overview recent progress and major developments, and consider future directions and potential applications of this subfield of nano-optics....

  3. Aerosol optical properties and direct radiative forcing at Taihu.

    Science.gov (United States)

    Lü, Rui; Yu, Xingna; Jia, Hailing; Xiao, Sihan

    2017-09-01

    Ground-based characteristics (optical, type, size, and radiative properties) of aerosols measured between 2005 and 2012 were investigated over the Taihu rim region, which encompasses the cities of Shanghai, Suzhou, Wuxi, and Changzhou. The aerosol optical depth (AOD) showed a distinct seasonal variation with the highest value in summer and the lowest AOD in winter. There was broadest frequency distribution with a multimodal structure in summer. The Ångström exponent (AE) showed high values during spring; the relative frequency of AE in the range of 0-0.8 was 5-10 times greater than that of other seasons. The samples with high AOD 440 and low AE 440-870 were mainly observed in spring, which is attributed to the relative abundance of coarse particles. The monthly aerosol volume size distributions presented a bimodal structure (fine and coarse modes). The coarse mode was dominant during spring, while the fine mode was predominant in other seasons. The main aerosol type over Taihu during all the seasons was the mixed small-particle category, followed by the urban/industrial category. The minimum single scattering albedo (SSA) occurred in winter, suggesting that atmosphere aerosol had a higher absorption. All monthly averaged asymmetry factors (ASY) had positive values and no distinct seasonal variation. Both high real (Re) and imaginary (Im) parts of the refractive index occurred in winter. The atmospheric warming effect of aerosol was more significant in winter compared with other seasons, with the averaged atmosphere aerosol radiative forcing (ARF) and the corresponding atmospheric heating rate up to +69.46  W·m -2 and 1.95  K·day -1 , respectively. There existed a significant positive correlation between AOD and ARF (absolute value), and the correlation coefficients (r) exceeded 0.86 in each season with maximum r in summer. Along with the increasing of the SSA, the aerosol radiative forcing efficiency (absolute value) showed a decreasing trend at the

  4. Acoustical and optical radiation pressures and the development of single beam acoustical tweezers

    OpenAIRE

    Thomas , Jean-Louis; Marchiano , Régis; Baresch , Diego

    2017-01-01

    International audience; Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and positioned micron size particles, biological samples or even atoms with subnanometer accuracy in three dimens...

  5. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation at Thessaloniki, Greece

    Directory of Open Access Journals (Sweden)

    A. V. Lindfors

    2013-04-01

    Full Text Available Pyranometer measurements of the solar surface radiation (SSR are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, was developed and tested using recent data from Thessaloniki, Greece. The effective AOD calculated using this method was found to agree well with co-located AERONET measurements, exhibiting a correlation coefficient of 0.9 with 2/3 of the data found within ±20% or ±0.05 of the AERONET AOD. This is similar to the performance of current satellite aerosol methods. Differences in the AOD as compared to AERONET can be explained by variations in the aerosol properties of the atmosphere that are not accounted for in the idealized settings used in the radiative transfer simulations, such as variations in the single scattering albedo and Ångström exponent. Furthermore, the method is sensitive to calibration offsets between the radiative transfer simulations and the pyranometer SSR. The method provides an opportunity of extending our knowledge of the atmospheric aerosol load to locations and times not covered by dedicated aerosol measurements.

  6. A novel DC Magnetron sputtering facility for space research and synchrotron radiation optics

    DEFF Research Database (Denmark)

    Hussain, A.M.; Christensen, Finn Erland; Pareschi, G.

    1998-01-01

    A new DC magnetron sputtering facility has been build up at the Danish Space Research Institute (DSRI), specially designed to enable uniform coatings of large area curved optics, such as Wolter-I mirror optics used in space telescopes and curved optics used in synchrotron radiation facilities...

  7. Optical imaging of oral pathological tissue using optical coherence tomography and synchrotron radiation computed microtomography

    Science.gov (United States)

    Cânjǎu, Silvana; Todea, Carmen; Sinescu, Cosmin; Negrutiu, Meda L.; Duma, Virgil; Mǎnescu, Adrian; Topalǎ, Florin I.; Podoleanu, Adrian Gh.

    2013-06-01

    The efforts aimed at early diagnosis of oral cancer should be prioritized towards developing a new screening instrument, based on optical coherence tomography (OCT), to be used directly intraorally, able to perform a fast, real time, 3D and non-invasive diagnosis of oral malignancies. The first step in this direction would be to optimize the OCT image interpretation of oral tissues. Therefore we propose plastination as a tissue preparation method that better preserves three-dimensional structure for study by new optical imaging techniques. The OCT and the synchrotron radiation computed microtomography (micro-CT) were employed for tissue sample analyze. For validating the OCT results we used the gold standard diagnostic procedure for any suspicious lesion - histopathology. This is a preliminary study of comparing features provided by OCT and Micro-CT. In the conditions of the present study, OCT proves to be a highly promising imaging modality. The use of x-ray based topographic imaging of small biological samples has been limited by the low intrinsic x-ray absorption of non-mineralized tissue and the lack of established contrast agents. Plastination can be used to enhance optical imagies of oral soft tissue samples.

  8. Time-resolved x-ray diffraction measurement of C{sub 60} under high pressure and temperature using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Horikawa, T [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Suito, K [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kobayashi, M [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Onodera, A [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2002-11-11

    C{sub 60} has been studied by means of time-resolved x-ray diffraction measurements using synchrotron radiation. Diffraction patterns were recorded at intervals of 1-10 min for samples under high pressure (12.5 and 14.3 GPa) and high temperature (up to 800 deg. C) for, at the longest, 3 h. Time, pressure, and temperature dependences of the C{sub 60} structure are presented and the relevance to the hardness of materials derived from C{sub 60} is discussed.

  9. Large arrays of discrete ionizing radiation detectors multiplexed using fluorescent optical converters

    International Nuclear Information System (INIS)

    Koslow, E.E.; Edelman, R.R.

    1985-01-01

    This invention provides a radiation imaging system employing arrays of scintillators. An object of the invention is to produce a detector with high spatial resolution, high gamma-photon absorption efficiency, excellent source and detector scatter rejection, and utilizing low-cost solid state opto-electronic devices. In one embodiment, it provides a radiation detection and conversion apparatus having an array of optically isolated radiation sensitive elements that emit optical radiation upon absorption of ionizing radiation. An array of channels, comprising a material that absorbs and traps the radiation emitted and transports it or radiation that has been shifted to longer wavelengths, is placed near the radiation-sensitive elements. Electro-optical detectors that convert the transported radiation into electrical signals are coupled to the channels. The activation of one of the electro-optical devices by radiation from one of the channels indicates that at least one of the radiation-sensitive elements near that channel has absorbed a quantity of radiation

  10. Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

    International Nuclear Information System (INIS)

    Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

    2017-01-01

    Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers. - Highlights: • Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. • Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. • However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. • Optical tweezers can trap, move and positioned micron size particles with subnanometer accuracy in three dimensions. • One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. • Acoustical tweezers overcome this limitation since the force scales as the field intensity divided by its propagation speed. • However, the feasibility of single beam acoustical tweezers was demonstrated only recently. • We propose a review of the strong similarities but also the specificities of acoustical

  11. Diffraction gauging

    International Nuclear Information System (INIS)

    Wilkens, P.H.

    1978-01-01

    This system of gauging is now being designed to fit on an Excello NC lathe to measure the form, accuracy, and size of external contoured surfaces as they approach the finish machined size. A template profile of the finished workpiece, but 0.003 in. bigger on radius, will be aligned with the workpiece using a reference diameter and face on the machining fixture to leave a gap between the profile of the template and workpiece. A helium--neon laser beam will be projected through this gap using a rotating retroreflector and a fixed laser. The resulting diffraction pattern produced by the laser beam passing through the template to workpiece gap will be reflected and focused on a fixed diode array via a second retroreflector which moves and remains in optical alignment with the first. These retroreflectors will be rotated about a center that will enable the laser beam, which is shaped in a long slit, to scan the template workpiece gap from the pole to the equator of the workpiece. The characteristic diffraction pattern will be detected by the fixed diode array, and the signal levels from this array will be processed in a mini-computer programmed to produce a best fit through the two minima of the diode signals. The separation of the two minima will yield the size of the workpiece to template gap and this information will be presented to the machine tool operator

  12. 1-W quasi-cw near-diffraction-limited semiconductor laser pumped optically by a fibre-coupled diode bar

    OpenAIRE

    Dhanjal, S.; Hoogland, S.; Roberts, J.S.; Hayward, R.A.; Clarkson, W.A.; Tropper, Anne

    2000-01-01

    We describe a diode-bar-pumped vertical-external-cavity surface-emitting semiconductor laser, which in quasi-cw operation emitted a peak power of >1 W at 1020 nm in a circular, near diffraction-limited beam.

  13. Radiation-resistance test on optical fiber for artificial satellite

    International Nuclear Information System (INIS)

    Morita, Yosuke; Seguchi, Tadao; Mori, Tatsuo; Miyaji, Yuji.

    1985-01-01

    Radiation resistance of a prototype optical fiber for use in artificial satellites is investigated under a long-term irradiation of gamma rays at relatively low dose rates. The optical fiber tested is composed of a pure silica core and an F-doped cladding. Various aspects of the relations between induced loss and irradiation time are observed and results obtained are discussed. It is generally accepted that a satellite and its equipment should be resistant to a total dose of about 1 x 10 6 rad. In the present test, accordingly, gamma ray irradiation is performed up to a total dose of 1 x 10 6 rad at a dose rate of 1 x 10 4 rad/h (for 100 h), 3 x 10 3 rad/h (333 h) and 1 x 10 3 rad/h (1000 h), and it is shown that the loss induced in this fiber at these dose rates is 23.6 - 27.2, 16.9 - 21.6 and 12.5 - 13.5 dB/km, respectively. On the other hand, it has been reported that the loss induced at the dose rate of 1 x 10 6 rad/h (1 h) is about 600 dB/km, which is much larger than the above values. From these results, the loss at a dose rate of 100 rad/h, which would be expected in a satellite, is estimated at about 10 dB/km. It is concluded that this prototype fiber has a sufficient capability for satellite use with respect to induced loss. (Nogami, K.)

  14. Radiation Dosimetry Using Three-Dimensional Optical Random Access Memories

    International Nuclear Information System (INIS)

    Moscovitch, M.

    2001-01-01

    The ability to determine particle type and energy plays an important role in the dosimetry of heavy charged particles (HCP) and neutrons. A new approach to radiation dosimetry is presented, which is shown to be capable of particle type and energy discrimination. This method is based on utilizing radiation induced changes in the digital information stored on three-dimensional optical random access memories (3D ORAM). 3D ORAM is a small cube (a few mm 3 ) composed of poly(methyl methacrylate) doped with a photochromic dye, and it was originally proposed as a memory device in high speed parallel computers. A Nd:YAG laser system is used to write and read binary information (bits) on the ORAM, which functions as a charged particle detector. Both the read and the write processes use two laser beams that simultaneously strike the material to cause a color change at their intersection (similar to the darkening of light-sensitive sunglasses when exposed to sunlight.) The laser produces color changes in the ORAM, which then reverts to the original color (''bit-flips'') at sites where energy is deposited from interaction with incident HCP or neutron-recoil protons. The feasibility of this approach was demonstrated both theoretically and experimentally. Calculations based on track structure theory (TST) predict that when HCP interact with the ORAM material, the local energy deposition is capable of inducing measurable ''bit-flips''. These predictions were recently confirmed experimentally using two types of ORAM systems, one based on spirobenzopyran and the other on anthracene, as the photochromic dyes

  15. Radiation dosimetry using three-dimensional optical random access memories

    International Nuclear Information System (INIS)

    Moscovitch, M.; Phillips, G.W.; Cullum, B.M.; Mobley, J.; Bogard, J.S.; Emfietzoglou, D.; Vo-Dinh, T.

    2002-01-01

    The ability to determine particle type and energy plays an important role in the dosimetry of heavy charged particles (HCP) and neutrons. A new approach to radiation dosimetry is presented, which is shown to be capable of particle type and energy discrimination. This method is based on utilising radiation induced changes in the digital information stored on three-dimensional optical random access memories (3D ORAM). 3D ORAM is a small cube (a few mm 3 ) composed of poly(methyl methacrylate) doped with a photochromic dye, and it was originally proposed as a memory device in high speed parallel computers. A Nd:YAG laser system is used to write and read binary information (bits) on the ORAM, which functions as a charged particle detector. Both the read and the write processes use two laser beams that simultaneously strike the material to cause a colour change at their intersection (similar to the darkening of light-sensitive sunglasses when exposed to sunlight). The laser produces colour changes in the ORAM, which then reverts to the original colour ('bit-flips') at sites where energy is deposited from interaction with incident HCP or neutron-recoil protons. The feasibility of this approach was demonstrated both theoretically and experimentally. Calculations based on track structure theory predict that when HCP interact with the ORAM material, the local energy deposition is capable of inducing measurable 'bit-flips'. These predictions were recently confirmed experimentally using two types of ORAM systems, one based on spirobenzopyran and the other on anthracene, as the photochromic dyes. (author)

  16. Radiation effects on radiation-hardened KU and KS-4V optical fibres

    International Nuclear Information System (INIS)

    Ivanov, A.A.; Tugarinov, S.N.; Kaschuck, Y.A.; Krasilnikov, A.V.; Bender, S.E.

    1999-01-01

    The aim of this work was to test the un-pretreated and the hardened (H 2 -loaded and pre-irradiated) KS-4V and KU optical fibres in reactor environment by in-situ measurements of both the radiation-induced loss and the luminescence in the visible spectral region. Both the radio-luminescent and the transmission spectra were in-situ detected during irradiation by charge-coupled-device (CCD) linear detector in the visible spectral region of 400 to 700 nm. The radiation induced loss spectra at the fast neutron fluence of 2*10 6 n/cm 2 shows the hardened, H 2 -loading and pre-irradiating effects in the both KU and KS-4V fibres. KU un-pretreated fibre shows a big radiation absorption band of non-bridging oxygen centered at the wavelength of 630 nm. It appears that the KS-4V hardened fibre has a specific point in the loss spectrum in the vicinity of 460 nm. Other measurements were performed, particularly after reactor shutdown and at 3 different neutron fluences with constant neutron flux after restarting

  17. 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....

  18. Comparison between ray-tracing and physical optics for the computation of light absorption in capillaries--the influence of diffraction and interference.

    Science.gov (United States)

    Qin, Yuan; Michalowski, Andreas; Weber, Rudolf; Yang, Sen; Graf, Thomas; Ni, Xiaowu

    2012-11-19

    Ray-tracing is the commonly used technique to calculate the absorption of light in laser deep-penetration welding or drilling. Since new lasers with high brilliance enable small capillaries with high aspect ratios, diffraction might become important. To examine the applicability of the ray-tracing method, we studied the total absorptance and the absorbed intensity of polarized beams in several capillary geometries. The ray-tracing results are compared with more sophisticated simulations based on physical optics. The comparison shows that the simple ray-tracing is applicable to calculate the total absorptance in triangular grooves and in conical capillaries but not in rectangular grooves. To calculate the distribution of the absorbed intensity ray-tracing fails due to the neglected interference, diffraction, and the effects of beam propagation in the capillaries with sub-wavelength diameter. If diffraction is avoided e.g. with beams smaller than the entrance pupil of the capillary or with very shallow capillaries, the distribution of the absorbed intensity calculated by ray-tracing corresponds to the local average of the interference pattern found by physical optics.

  19. Radiation-hard/high-speed parallel optical links

    International Nuclear Information System (INIS)

    Gan, K.K.; Buchholz, P.; Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S.; Wiese, A.; Ziolkowski, M.

    2014-01-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel VCSEL (Vertical Cavity Surface Emitting Laser) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. The performance of the first prototype ASIC up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Some preliminary results of the design will be presented

  20. LCLS-S1 optical transition radiation monitor

    International Nuclear Information System (INIS)

    Berg, W.J.; Yang, B.; Erwin, L.L.; Shoaf, S.E.

    2008-01-01

    Argonne National Laboratory has developed a high- resolution optical transition radiation (OTR) imaging monitor for the Linac Coherent Light Source (LCLS) injection linac at SLAC. The imaging station,OTR-S1, will be located at the S1 spectrometer with a beam energy of 135 MeV. The system will be used to acquire 2-D transverse beam distributions of the accelerated photocathode-gun-generated electron beam. We anticipate an average beam current of 0.2 to 1 nC and nominal beam spot size of 130 mum (sigmax), 100 mum (sigmay). The imaging system was designed for a field of view x/y: 10 times 7.5 mm. The spatial resolution of ∼12 microns was verified over the central 5times4 mm region in the visible. A 12-bit digital camera acquires the image and a Mac-based digital frame-capturing system was employed for the initial lab-based performance testing of the device. We report on system development, testing methods, and data analysis.

  1. Errors in the universal and sufficient heuristic criteria of estimating validity limits of geometric optics and of the geometric theory of diffraction

    International Nuclear Information System (INIS)

    Borovikov, V.A.; Kinber, B.E.

    1988-01-01

    The heuristic criteria (HC) of validity of geometric optics (GO) and of the geometric theory of diffraction (GTD), suggested in [2-7, 13, 14] and based on identifying the physical volume occupied by the ray with the Fresnel volume (FV) introduced in these papers (i.e., the envelope of the first Fresnel zone), are analyzed. Numerous examples of HC invalidity are given, as well as the reasons. In particular, HC provide an incorrect answer for all GO problems with caustics, since in these problems there always exists a ray, whose FV is nonlocal and covers the FV of other rays. The HC are shown to be unsuitable for multiple ray GTD problems, as well as for the simplest problems of diffraction of a cylindrical wave by a half-plane and of a plane wave by a curved half-plane

  2. Characterization of CuCl quantum dots grown in NaCl single crystals via optical measurements, X-ray diffraction, and transmission electron microscopy

    Science.gov (United States)

    Miyajima, Kensuke; Akatsu, Tatsuro; Itoh, Ken

    2018-05-01

    We evaluated the crystal size, shape, and alignment of the lattice planes of CuCl quantum dots (QDs) embedded in NaCl single crystals by optical measurements, X-ray diffraction (XRD) patterns, and transmission electron microscopy (TEM). We obtained, for the first time, an XRD pattern and TEM images for CuCl QDs in NaCl crystals. The XRD pattern showed that the lattice planes of the CuCl QDs were parallel to those of the NaCl crystals. In addition, the size of the QDs was estimated from the diffraction width. It was apparent from the TEM images that almost all CuCl QDs were polygonal, although some cubic QDs were present. The mean size and size distribution of the QDs were also obtained. The dot size obtained from optical measurements, XRD, and TEM image were almost consistent. Our new findings can help to reveal the growth mechanism of semiconductor QDs embedded in a crystallite matrix. In addition, this work will play an important role in progressing the study of optical phenomena originating from assembled semiconductor QDs.

  3. The applicability of physical optics in the millimetre and sub-millimetre spectral region. Part I: The ray tracing with diffraction on facets method

    Science.gov (United States)

    Baran, A. J.; Hesse, Evelyn; Sourdeval, Odran

    2017-03-01

    Future satellite missions, from 2022 onwards, will obtain near-global measurements of cirrus at microwave and sub-millimetre frequencies. To realise the potential of these observations, fast and accurate light-scattering methods are required to calculate scattered millimetre and sub-millimetre intensities from complex ice crystals. Here, the applicability of the ray tracing with diffraction on facets method (RTDF) in predicting the bulk scalar optical properties and phase functions of randomly oriented hexagonal ice columns and hexagonal ice aggregates at millimetre frequencies is investigated. The applicability of RTDF is shown to be acceptable down to size parameters of about 18, between the frequencies of 243 and 874 GHz. It is demonstrated that RTDF is generally well within about 10% of T-matrix solutions obtained for the scalar optical properties assuming hexagonal ice columns. Moreover, on replacing electromagnetic scalar optical property solutions obtained for the hexagonal ice aggregate with the RTDF counterparts at size parameter values of about 18 or greater, the bulk scalar optical properties can be calculated to generally well within ±5% of an electromagnetic-based database. The RTDF-derived bulk scalar optical properties result in brightness temperature errors to generally within about ±4 K at 874 GHz. Differing microphysics assumptions can easily exceed such errors. Similar findings are found for the bulk scattering phase functions. This finding is owing to the scattering solutions being dominated by the processes of diffraction and reflection, both being well described by RTDF. The impact of centimetre-sized complex ice crystals on interpreting cirrus polarisation measurements at sub-millimetre frequencies is discussed.

  4. Ionizing Radiation Detectors Based on Ge-Doped Optical Fibers Inserted in Resonant Cavities

    Directory of Open Access Journals (Sweden)

    Saverio Avino

    2015-02-01

    Full Text Available The measurement of ionizing radiation (IR is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. Optical fiber sensors have recently proven good candidates as radiation dosimeters. Here we investigate the effect of IR on germanosilicate optical fibers. A piece of Ge-doped fiber enclosed between two fiber Bragg gratings (FBGs is irradiated with gamma radiation generated by a 6 MV medical linear accelerator. With respect to other FBG-based IR dosimeters, here the sensor is only the bare fiber without any special internal structure. A near infrared laser is frequency locked to the cavity modes for high resolution measurement of radiation induced effects on the fiber optical parameters. In particular, we observe a variation of the fiber thermo-optic response with the radiation dose delivered, as expected from the interaction with Ge defect centers, and demonstrate a detection limit of 360 mGy. This method can have an impact in those contexts where low radiation doses have to be measured both in small volumes or over large areas, such as radiation therapy and radiation protection, while bare optical fibers are cheap and disposable.

  5. Radiation Hard Multi-Layer Optical Coatings, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Next generation space telescopes require advanced optical coatings to provide low loss transmission of light in a variety of spectral ranges and protect optical...

  6. All-optical switching of the transmission of electromagnetic radiation through subwavelength apertures

    NARCIS (Netherlands)

    Janke, C.; Gómez Rivas, J.; Haring Bolivar, P.; Kurz, H.

    2005-01-01

    Unprecedented optical control of the surface plasmon polariton assisted transmission of terahertz radiation through subwavelength apertures is rendered possible by carrier-induced changes to the dielectric properties of a semiconductor grating. Although the study presented is static, the extension

  7. Optical absorption study of radiation and thermal effects in Brazilian samples of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Furtado, W.

    1988-03-01

    A detailed analysis of the optical absorption spectra of five varieties of Brazilian spodumene is presented. The samples were submitted to heat treatments and irradiated with gamma rays, x radiation, electrons and ultraviolet light. (M.C.K.) [pt

  8. Directional Radiometry and Radiative Transfer: the Convoluted Path From Centuries-old Phenomenology to Physical Optics

    Science.gov (United States)

    Mishchenko, Michael I.

    2014-01-01

    This Essay traces the centuries-long history of the phenomenological disciplines of directional radiometry and radiative transfer in turbid media, discusses their fundamental weaknesses, and outlines the convoluted process of their conversion into legitimate branches of physical optics.

  9. The magneto-optical gradient effect in anexchange-biased thin film: experimental evidencefor classical diffraction theory

    Czech Academy of Sciences Publication Activity Database

    Schäfer, R.; Hamann, C.; McCord, J.; Schultz, L.; Kamberský, Vladimír

    2010-01-01

    Roč. 12, č. 5 (2010), 053006/1-053006/10 ISSN 1367-2630 Institutional research plan: CEZ:AV0Z10100521 Keywords : magnetooptics * magnetic domains * light diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.849, year: 2010

  10. A scintillation testing technology at a viewpoint of optical test. At a memory of winning of the Radiation Prize (Prize of Encouragement)

    International Nuclear Information System (INIS)

    Maekawa, Tatsuyuki

    2000-01-01

    In a 'summer school' held at Matsushima, a series of developmental results had been introduced on a wavelength shift type beta-ray detector and others recently progressed by author at a viewpoint of 'new reconsideration on scintillation testing, one of the oldest radiation testing technology for an optical testing'. As a chance to write this theme again was obtained at present, here were introduced on trial and errors, backgrounds on ideas, pains for trial production and so forth at a process of putting together them for actual technologies and products under combining a series of ideas with their needs. Here were newly introduced on developmental backgrounds, points for practicability, and so forth on optical radiation testing technology which had been developed by authors. By upgrading of radiation resistance on the optical fibers themselves, developments for not only radiation testing but also instrumentation in storage vessel specific to nuclear instrumentation are considered in future. And, some findings on new elements and techniques, such as application of radiation to refractive index change due to much minute exotherm, application of Cherenkov phenomenon in glass, fiber grating and interference test assembles a minute diffraction lattice into a core, and so forth are found recently, which will be expected for their future developments. (G.K.)

  11. A scintillation testing technology at a viewpoint of optical test. At a memory of winning of the Radiation Prize (Prize of Encouragement)

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Tatsuyuki [Toshiba Corp., Kawasaki, Kanagawa (Japan)

    2000-04-01

    In a 'summer school' held at Matsushima, a series of developmental results had been introduced on a wavelength shift type beta-ray detector and others recently progressed by author at a viewpoint of 'new reconsideration on scintillation testing, one of the oldest radiation testing technology for an optical testing'. As a chance to write this theme again was obtained at present, here were introduced on trial and errors, backgrounds on ideas, pains for trial production and so forth at a process of putting together them for actual technologies and products under combining a series of ideas with their needs. Here were newly introduced on developmental backgrounds, points for practicability, and so forth on optical radiation testing technology which had been developed by authors. By upgrading of radiation resistance on the optical fibers themselves, developments for not only radiation testing but also instrumentation in storage vessel specific to nuclear instrumentation are considered in future. And, some findings on new elements and techniques, such as application of radiation to refractive index change due to much minute exotherm, application of Cherenkov phenomenon in glass, fiber grating and interference test assembles a minute diffraction lattice into a core, and so forth are found recently, which will be expected for their future developments. (G.K.)

  12. Optical properties and radiation response of Ce{sup 3+}-doped GdScO{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yamaji, Akihiro; Fujimoto, Yutaka; Futami, Yoshisuke; Yokota, Yuui; Kurosawa, Shunsuke [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Kochurikhin, Vladimir [General Physics Institute, 38 Vavilov Str., 119991 Moscow (Russian Federation); Yanagida, Takayuki [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yoshikawa, Akira [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2012-12-15

    10%-Ce doped GdScO{sub 3} perovskite type single crystal was grown by the Czochralski process. The Ce concentration in the crystal was measured. No impurity phases were observed by powder X-ray diffraction analysis. We evaluated the optical and radiation properties of the grown crystal. Ce:GdScO{sub 3} crystal showed photo- and radio-luminescence peaks due to Ce{sup 3+} of 5d-4f transition and colour centre. The photoluminescence decay time was sub-ns order. The relative light yield under 5.5 MeV alpha-ray excitation was calculated to be approximately 9% of BGO. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Optical imaging beyond the diffraction limit by SNEM: Effects of AFM tip modifications with thiol monolayers on imaging quality

    NARCIS (Netherlands)

    Cumurcu, Aysegul; Diaz, J.; Lindsay, I.D.; de Beer, Sissi; Duvigneau, Joost; Schön, Peter Manfred; Vancso, Gyula J.

    2015-01-01

    Tip-enhanced nanoscale optical imaging techniques such as apertureless scanning near-field optical microscopy (a-SNOM) and scanning near-field ellipsometric microscopy (SNEM) applications can suffer from a steady degradation in performance due to adhesion of atmospheric contaminants to the metal

  14. The effects of wallerian degeneration of the optic radiations demonstrated by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Savoiardo, M.; Grisoli, M.; Forester, M.; D' Incerti, L.; Farina, L. (Dept. of Neuroradiology, Ist. Nazionale Neurologico C. Besta, Milan (Italy)); Pareyson, D. (Dept. of Neurology, Ist. Nazionale Neurologico C. Besta, Milan (Italy))

    1992-08-01

    The effects of wallerian degeneration can be demonstrated by MRI as abnormal signal along the course of the degenerate fibres; they have previously been reported in the corticospinal tract. We report two cases of wallerian degeneration of the right optic radiations due to lesions of the right lateral geniculate body. The anatomy and the MRI visibility of the normal optic radiations are briefly discussed. (orig.).

  15. Directional radiometry and radiative transfer: The convoluted path from centuries-old phenomenology to physical optics

    International Nuclear Information System (INIS)

    Mishchenko, Michael I.

    2014-01-01

    This Essay traces the centuries-long history of the phenomenological disciplines of directional radiometry and radiative transfer in turbid media, discusses their fundamental weaknesses, and outlines the convoluted process of their conversion into legitimate branches of physical optics. - Highlights: • History of phenomenological radiometry and radiative transfer is described. • Fundamental weaknesses of these disciplines are discussed. • The process of their conversion into legitimate branches of physical optics is summarized

  16. The effects of wallerian degeneration of the optic radiations demonstrated by MRI

    International Nuclear Information System (INIS)

    Savoiardo, M.; Grisoli, M.; Forester, M.; D'Incerti, L.; Farina, L.; Pareyson, D.

    1992-01-01

    The effects of wallerian degeneration can be demonstrated by MRI as abnormal signal along the course of the degenerate fibres; they have previously been reported in the corticospinal tract. We report two cases of wallerian degeneration of the right optic radiations due to lesions of the right lateral geniculate body. The anatomy and the MRI visibility of the normal optic radiations are briefly discussed. (orig.)

  17. Electro-optical and Magneto-optical Sensing Apparatus and Method for Characterizing Free-space Electromagnetic Radiation

    Science.gov (United States)

    Zhang, Xi-Cheng; Riordan, Jenifer Ann; Sun, Feng-Guo

    2000-08-29

    Apparatus and methods for characterizing free-space electromagnetic energy, and in particular, apparatus/method suitable for real-time two-dimensional far-infrared imaging applications are presented. The sensing technique is based on a non-linear coupling between a low-frequency electric (or magnetic) field and a laser beam in an electro-optic (or magnetic-optic) crystal. In addition to a practical counter-propagating sensing technique, a co-linear approach is described which provides longer radiated field-optical beam interaction length, thereby making imaging applications practical.

  18. Depth-of-field effects in wiggler radiation sources: Geometrical versus wave optics

    Directory of Open Access Journals (Sweden)

    Richard P. Walker

    2017-02-01

    Full Text Available A detailed analysis is carried out of the optical properties of synchrotron radiation emitted by multipole wigglers, concentrating on the effective source size and brightness and the so-called “depth of field” effects, concerning which there has been some controversy in the literature. By comparing calculations made with both geometrical optics and wave optics methods we demonstrate that the two approaches are not at variance, and that the wave optics results tend towards those of geometrical optics under well-defined conditions.

  19. Radiation-induced optic neuropathy 4 years after radiation: report of a case followed up with MRI

    International Nuclear Information System (INIS)

    Piquemal, R.; Renard, J.P.; Cottier, J.P.; Herbreteau, D.; Arsene, S.; Rospars, C.; Lioret, E.; Jan, M.

    1998-01-01

    We report a case of radiation-induced optic neuropathy in a 32-year-old man with Cushing's disease and a recurrent tumour of the left cavernous sinus. The patient experienced rapid, painless loss of vision 4 years after treatment without recurrence of tumour or other visual disorder. MRI showed enlargement and contrast enhancement of the optic chiasm. A year later the patient was almost blind and MRI showed atrophy and persistent contrast enhancement of the chiasm. (orig.)

  20. Ultrastructure of a hexagonal array in exosporium of a highly sporogenic mutant of Clostridium botulinum type A revealed by electron microscopy using optical diffraction and filtration.

    Science.gov (United States)

    Masuda, K; Kawata, T; Takumi, K; Kinouchi, T

    1980-01-01

    The ultrastructure of a hexagonal array in the exosporium from spores of a highly sporogenic mutant of Clostridium botulinum type A strain 190L was studied by electron microscopy of negatively stained exosporium fragments using optical diffraction and filtration. The exosporium was composed of three or more lamellae showing and equilateral, hexagonal periodicity. Images of the single exosporium layer from which the noise had been filtered optically revealed that the hexagonally arranged, morphological unit of the exosporium was composed of three globular subunits about 2.1 nm in diameter which were arranged at the vertices of an equilateral triangle with sides of about 2.4 nm. The morphological units were arranged with a spacing of about 4.5 nm. the adjacent globular subunits appeared to be interconnected by delicate linkers.

  1. Extended ABCD matrix formalism for the description of femtosecond diffraction patterns; application to femtosecond digital in-line holography with anamorphic optical systems.

    Science.gov (United States)

    Brunel, Marc; Shen, Huanhuan; Coetmellec, Sebastien; Lebrun, Denis

    2012-03-10

    We present a new model to predict diffraction patterns of femtosecond pulses through complex optical systems. The model is based on the extension of an ABCD matrix formalism combined with generalized Huygens-Fresnel transforms (already used in the CW regime) to the femtosecond regime. The model is tested to describe femtosecond digital in-line holography experiments realized in situ through a cylindrical Plexiglas pipe. The model allows us to establish analytical relations that link the holographic reconstruction process to the experimental parameters of the pipe and of the incident beam itself. Simulations and experimental results are in good concordance. Femtosecond digital in-line holography is shown to allow significant coherent noise reduction, and this model will be particularly efficient to describe a wide range of optical geometries. More generally, the model developed can be easily used in any experiment where the knowledge of the precise evolution of femtosecond transverse patterns is required.

  2. Diffractive interactions

    International Nuclear Information System (INIS)

    Del Duca, V.; Marage, P.

    1996-08-01

    The general framework of diffractive deep inelastic scattering is introduced and reports given in the session on diffractive interactions at the international workshop on deep-inelastic scattering and related phenomena, Rome, April 1996, are presented. (orig.)

  3. Static tensile deformation behavior of a lean duplex stainless steel studied by in situ neutron diffraction and synchrotron radiation white x-rays

    International Nuclear Information System (INIS)

    Tsuchida, Noriyuki; Kawahata, Taiji; Ishimaru, Eiichiro; Takahashi, Akihiko; Suzuki, Hiroshi; Shobu, Takahisa

    2013-01-01

    To investigate the tensile deformation behavior of a lean duplex stainless steel (S32101) from the viewpoints of plastic deformability among phases or grains, we performed static tensile tests, in situ neutron diffraction, and white x-ray diffraction experiments at room temperature. In the static tensile tests, the S32101 steel displayed a larger uniform elongation and a better tensile strength-uniform elongation balance than a commercial SUS329J4L duplex stainless steel. A larger uniform elongation of S32101 is associated with the macroscopic work hardening behavior that a work hardening rate higher than the flow stress can maintain up until high true strains. From the experimental results of synchrotron radiation white x-ray diffraction experiments, the hard phase of S32101 was changed from the ferrite (α) phase to austenite (γ) one during tensile deformation. This led to a larger stress partitioning between the phases at the latter stage of deformation. From the experimental results of in situ neutron diffraction, it was found that the stress partitioning of the γ phase in the S32101 was the largest among the present results. Therefore, the larger work hardening rate of S32101 can be explained by the large stress partitioning of the γ phase, that between γ and α phases and γ volume fraction. (author)

  4. Diffraction theory

    NARCIS (Netherlands)

    Bouwkamp, C.J.

    1954-01-01

    A critical review is presented of recent progress in classical diffraction theory. Both scalar and electromagnetic problems are discussed. The report may serve as an introduction to general diffraction theory although the main emphasis is on diffraction by plane obstacles. Various modifications of

  5. Importance of representing optical depth variability for estimates of global line-shaped contrail radiative forcing.

    Science.gov (United States)

    Kärcher, Bernd; Burkhardt, Ulrike; Ponater, Michael; Frömming, Christine

    2010-11-09

    Estimates of the global radiative forcing by line-shaped contrails differ mainly due to the large uncertainty in contrail optical depth. Most contrails are optically thin so that their radiative forcing is roughly proportional to their optical depth and increases with contrail coverage. In recent assessments, the best estimate of mean contrail radiative forcing was significantly reduced, because global climate model simulations pointed at lower optical depth values than earlier studies. We revise these estimates by comparing the probability distribution of contrail optical depth diagnosed with a climate model with the distribution derived from a microphysical, cloud-scale model constrained by satellite observations over the United States. By assuming that the optical depth distribution from the cloud model is more realistic than that from the climate model, and by taking the difference between the observed and simulated optical depth over the United States as globally representative, we quantify uncertainties in the climate model's diagnostic contrail parameterization. Revising the climate model results accordingly increases the global mean radiative forcing estimate for line-shaped contrails by a factor of 3.3, from 3.5 mW/m(2) to 11.6 mW/m(2) for the year 1992. Furthermore, the satellite observations and the cloud model point at higher global mean optical depth of detectable contrails than often assumed in radiative transfer (off-line) studies. Therefore, we correct estimates of contrail radiative forcing from off-line studies as well. We suggest that the global net radiative forcing of line-shaped persistent contrails is in the range 8-20 mW/m(2) for the air traffic in the year 2000.

  6. Implementation of European Directive on Optical Radiation Safety takes place in May 2010

    NARCIS (Netherlands)

    Wieringa, F.P.

    2009-01-01

    At the latest by May 10th 2010, Directive 2006/25/EC regarding the exposure of workers to risks arising from artificial optical radiation must be implemented by all EU-member states, thus legally adopting ICNIRP limit values for ultraviolet, visible and infrared radiation. For IUVA-members the

  7. Radiation effects on optical components of a laser radar sensor designed for remote metrology in ITER

    International Nuclear Information System (INIS)

    Menon, M.M.; Grann, E.B.; Slotwinski, A.

    1997-09-01

    A frequency modulated laser radar is being developed for in-vessel metrology and viewing of plasma-facing surfaces. Some optical components of this sensor must withstand intense gamma radiation (3 x 10 6 rad/h) during operation. The authors have tested the effect of radiation on a silica core polarization maintaining optical fiber and on TeO 2 crystals at doses up to ∼ 10 9 rad. Additional tests are planned for evaluating the performance of a complete acousto-optic (AO) scanning device. The progress made in these tests is also described

  8. Measurement of radiation damage on an epoxy-based optical glue

    International Nuclear Information System (INIS)

    Huang, H.C.; Peng, K.C.; Sahu, S.K.; Ueno, K.; Chang, Y.H.; Wang, C.H.; Hou, W.S.

    1997-01-01

    We measured the radiation damage on an optical glue called Eccobond-24, which is a candidate for CsI and BGO crystal calorimeters of the BELLE detector of the KEK B-factory. Absorption spectrophotometry in the range 300-800 nm was used to monitor the radiation damage. The maximum equivalent dose was 1.64 Mrad. The glue shows effects of damage, but is acceptable for the radiation level in the above-mentioned experiment. (orig.)

  9. Nonlinear-optical generation of short-wavelength radiation controlled by laser-induced interference structures

    International Nuclear Information System (INIS)

    Popov, A K; Kimberg, V V

    1998-01-01

    A study is reported of the combined influence of laser-induced resonances in the energy continuum, of splitting of discrete resonances in the field of several strong radiations, and of absorption of the initial and generated radiations on totally resonant parametric conversion to the short-wavelength range. It is shown that the radiation power can be increased considerably by interference processes involving quantum transitions. (nonlinear optical phenomena and devices)

  10. Optical radiation emitted by a silver surface bombarded by low-energy electrons

    International Nuclear Information System (INIS)

    Miserey, F.; Lebon, P.; Septier, A.; Trehin, F.; Beaugrand, C.

    1975-01-01

    Thick silver targets are obtained on flat glass discs by evaporation in a UHV cell (p -10 torr) and their optical coefficients measured by ellipsometry. A field-emission electron gun bombards a limited region of the target, corresponding to the entry pupil of a light spectrometer. Radiation emitted in the domain 250-600nm is analyzed for both normal and parallel polarizations. Spectral distributions of photons are obtained by using a very sensitive counting device including a multi channel analyzer. First experimental results concerning optical radiation generated by 6keV electrons are reported and compared to Transition Radiation and Bremsstrahlung theoretical spectra [fr

  11. Objective evaluation of improvement in optic neuropathy following radiation therapy for thyroid eye disease

    International Nuclear Information System (INIS)

    Rush, Stephen; Winterkorn, Jacqueline; Zak, Rochelle

    2000-01-01

    Purpose: While the literature supports the use of radiation therapy for thyroid eye disease, it does not sufficiently describe in detail the results of radiation therapy for optic neuropathy associated with thyroid eye disease. The objective of this study is to quantify the changes in parameters of optic neuropathy after orbital irradiation for thyroid eye disease. Methods and Materials: Twelve consecutive patients with optic neuropathy from thyroid eye disease were followed by a single neuro-ophthalmology practice and treated by one radiation oncologist with radiation therapy from 1991 through 1995. All cases were prospectively followed for visual acuity, color vision, mean deviation, and/or foveal sensitivity and afferent pupillary defect. All patients received 2000 cGy in 10 fractions with megavoltage irradiation to the orbits. Results: Ten of 12 patients were evaluated for follow-up (one moved out of this country and one had a stroke, which confounded interpretation of examination results). An analysis was performed retrospectively while treatment and evaluation remained uniform. Five men and five women formed the basis of this study with a median age of 60 years (35-76 years). Nineteen eyes were evaluated for thyroid optic neuropathy. Improvement in optic nerve function occurred in eight of ten patients. Improvement was seen either during radiotherapy or within 2 weeks of completion. No long-term adverse effects were noted. Conclusion: This study objectively demonstrates improvement in optic neuropathy from radiation therapy for thyroid eye disease

  12. Effects of Polarization–Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

    International Nuclear Information System (INIS)

    Wen, Xiao; De-Wen, Liu; Yang, Liu; Xiao-Su, Yi; Lin, Cong

    2008-01-01

    In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation. Photonic components of FOGs are affected by radiation, especially the polarization-maintaining (PM) fibre coil. In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 60 Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rate is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG

  13. Multi-dimensional fiber-optic radiation sensor for ocular proton therapy dosimetry

    International Nuclear Information System (INIS)

    Jang, K.W.; Yoo, W.J.; Moon, J.; Han, K.T.; Park, B.G.; Shin, D.; Park, S-Y.; Lee, B.

    2012-01-01

    In this study, we fabricated a multi-dimensional fiber-optic radiation sensor, which consists of organic scintillators, plastic optical fibers and a water phantom with a polymethyl methacrylate structure for the ocular proton therapy dosimetry. For the purpose of sensor characterization, we measured the spread out Bragg-peak of 120 MeV proton beam using a one-dimensional sensor array, which has 30 fiber-optic radiation sensors with a 1.5 mm interval. A uniform region of spread out Bragg-peak using the one-dimensional fiber-optic radiation sensor was obtained from 20 to 25 mm depth of a phantom. In addition, the Bragg-peak of 109 MeV proton beam was measured at the depth of 11.5 mm of a phantom using a two-dimensional sensor array, which has 10×3 sensor array with a 0.5 mm interval.

  14. Long term bleaching of optical glasses darkened by Co60 ionizing radiation

    International Nuclear Information System (INIS)

    Wirtenson, G.R.; White, R.H.

    1997-01-01

    Typical camera designs include optical glass elements that may be affected by the ionizing radiation present in the natural space environment. Ordinary optical glasses darken at low (10(to the 3rd power) rad) dose levels when exposed to ionizing radiation. This darkening decreases the sensitivity of optical sensors. Optical glass flats of FK 51, LaK 0, PK 51A, and ZK Ny were exposed to a 10.6 krad dose of ionizing radiation. Spectrophotometer traces determined the transmittance of the samples as a function of wavelength in the range 350 to 850 nm before and at various time intervals after the irradiation. These measured values were then use to evaluate the rate of recovery or ''bleaching'' of the exposed samples. To prevent accelerated bleaching, the samples were kept at room temperature and away from light, except during measurement. Tables of the measured data and plots of the transmissivity vs. wavelength at various times after irradiation are presented

  15. Radiation-induced transient attenuation of optical fibers at 800 and 1300 nm

    International Nuclear Information System (INIS)

    Looney, L.D.; Lyons, P.B.

    1987-01-01

    Radiation-induced absorption in optical fibers has been a subject of considerable interest throughout the world. As availability and applications of fibers have evolved from ''first window'' systems operating near 850 nm to ''second window'' systems near 1300 nm, interest in wavelength dependence of radiation effects in optical fibers has similarly evolved. The present work summarizes second-window, radiation-induced transient absorption measurements in optical fibers for times shorter than 5 μs. Comparisons to first window data for these fibers are also presented. Only high purity silica fibers with low-OH concentrations were used in the present study to avoid the large OH absorption band in this region. This paper also collects first window data on several high-OH optical fibers

  16. Measuring the nematic order of suspensions of colloidal fd virus by x-ray diffraction and optical birefringence

    International Nuclear Information System (INIS)

    Purdy, Kirstin R.; Dogic, Zvonimir; Fraden, Seth; Ruehm, Adrian; Lurio, Lawrence; Mochrie, Simon G. J.

    2003-01-01

    The orientational distribution function of the nematic phase of suspensions of the semiflexible rodlike virus fd is measured by x-ray diffraction as a function of concentration and ionic strength. X-ray diffraction from a single-domain nematic phase of fd is influenced by interparticle correlations at low angle, while only intraparticle scatter contributes at high angle. Consequently, the angular distribution of the scattered intensity arises from only the single-particle orientational distribution function at high angle but it also includes spatial and orientational correlations at low angle. Experimental measurements of the orientational distribution function from both the interparticle (structure factor) and intraparticle (form factor) scattering were made to test whether the correlations present in interparticle scatter influence the measurement of the single-particle orientational distribution function. It was found that the two types of scatter yield consistent values for the nematic order parameter. It was also found that x-ray diffraction is insensitive to the orientational distribution function's precise form, and the measured angular intensity distribution is described equally well by both Onsager's trial function and a Gaussian. At high ionic strength, the order parameter S of the nematic phase coexisting with the isotropic phase approaches theoretical predictions for long semiflexible rods S=0.55, but deviations from theory increase with decreasing ionic strength. The concentration dependence of the nematic order parameter also better agrees with theoretical predictions at high ionic strength indicating that electrostatic interactions have a measurable effect on the nematic order parameter. The x-ray order parameters are shown to be proportional to the measured birefringence, and the saturation birefringence of fd is determined enabling a simple, inexpensive way to measure the order parameter. Additionally, the spatial ordering of nematic fd was probed

  17. Fused Silica Final Optics for Inertial Fusion Energy: Radiation Studies and System-Level Analysis

    International Nuclear Information System (INIS)

    Latkowski, Jeffery F.; Kubota, Alison; Caturla, Maria J.; Dixit, Sham N.; Speth, Joel A.; Payne, Stephen A.

    2003-01-01

    The survivability of the final optic, which must sit in the line of sight of high-energy neutrons and gamma rays, is a key issue for any laser-driven inertial fusion energy (IFE) concept. Previous work has concentrated on the use of reflective optics. Here, we introduce and analyze the use of a transmissive final optic for the IFE application. Our experimental work has been conducted at a range of doses and dose rates, including those comparable to the conditions at the IFE final optic. The experimental work, in conjunction with detailed analysis, suggests that a thin, fused silica Fresnel lens may be an attractive option when used at a wavelength of 351 nm. Our measurements and molecular dynamics simulations provide convincing evidence that the radiation damage, which leads to optical absorption, not only saturates but that a 'radiation annealing' effect is observed. A system-level description is provided, including Fresnel lens and phase plate designs

  18. Fiber optics in the BNL Booster radiation environment

    International Nuclear Information System (INIS)

    Beadle, E.R.

    1991-01-01

    The Booster instrumentation uses analog and digital fiber optic links, designed to withstand at least 50 krads without performance degradation. The links use inexpensive and commercially available components that operate at a center wavelength of 820 nm. The analog link operates to 30 MHz over a 200 m fiber and can provide insertion gain. The digital link provides 60 ns timing pulses without the dispersive effects of coaxial cables. The optical fiber is a step-index hard clad silica type with a 200 micron core. This paper presents the component selection criteria, link design, installation, testing and performance for the optical links in the Booster instrumentation systems

  19. Higher-order-structure formation in liquid crystal epoxy thermosets investigated by synchrotron radiation-wide-angle X-ray diffraction

    International Nuclear Information System (INIS)

    Maeda, Rina; Okuhara, Kenta; Nakamura, Akihiro; Hayakawa, Teruaki; Uehara, Yasushi; Motoya, Tsukasa; Nobutoki, Hideharu

    2016-01-01

    We report the investigation of the mesophase transformations of a liquid crystalline molecule with terminal epoxy groups from the initial stages of curing with a diamine compound. The ordered arrangement of molecules within the smectic layers in the thermoset formed at the end of the curing process was characterized by synchrotron radiation-wide-angle X-ray diffraction (SR-WAXD). Data from this experiment helps us understand the phase transitions from the nematic to smectic phases of curing liquid crystalline epoxies. (author)

  20. Investigation of (Ga,In) (As,P)/InP single heterostructures by means of extremely asymmetrical Bragg diffraction using synchrotron radiation

    International Nuclear Information System (INIS)

    Bruehl, H.G.; Pietsch, U.; Lengeler, B.

    1988-01-01

    Synchrotron radiation was used to measure the rocking curves from (Ga, In) (As, P) single layers grown on an InP (100) oriented substrate. The incident angle was varied (changing correspondingly the X-ray incident-beam wavelength) in order to measure at extremely asymmetrical Bragg diffraction down to a glancing angle of 0.35 0 . The measured rocking curves could be interpreted by the semi-kinematic model of Petrashen with corrections for X-ray refraction and for the width of the rocking curve from the extended dynamical theory. (orig.)