WorldWideScience

Sample records for optical diffraction radiation

  1. Nonintercepting electron beam size monitor using optical diffraction radiation interference

    Directory of Open Access Journals (Sweden)

    A. Cianchi

    2011-10-01

    Full Text Available In recent years, the use of diffraction radiation (DR, emitted when a charged particle beam passes through a rectangular slit, has been proposed and successfully tested as a nonintercepting diagnostic of high brightness beams. However, some problems related to the control of the particle trajectory through the slit still remain. If an additional slit is placed in front of the first one, at a distance shorter than the radiation formation length, interference between the forward diffraction radiation from the upstream slit and the backward diffraction radiation from the downstream slit can be observed. In this paper we report the first experimental observation of this effect, which we call here optical diffraction radiation interference (ODRI. If the two slits have different dimensions and are not aligned on the same axis, the properties of the ODRI pattern can be effectively used for nonintercepting beam diagnostics, especially for the unambiguously determination of the beam size. Indeed, the advantage of ODRI compared with a single aperture DR screen is due to the reduction of synchrotron radiation background, the increase of sensitivity for transverse beam dimensions, and the possibility to separate effects caused by the beam size and by beam offset within the slit.

  2. Advanced simulations of optical transition and diffraction radiation

    Directory of Open Access Journals (Sweden)

    T. Aumeyr

    2015-04-01

    Full Text Available Charged particle beam diagnostics is a key task in modern and future accelerator installations. The diagnostic tools are practically the “eyes” of the operators. The precision and resolution of the diagnostic equipment are crucial to define the performance of the accelerator. Transition and diffraction radiation (TR and DR are widely used for electron beam parameter monitoring. However, the precision and resolution of those devices are determined by how well the production, transport and detection of these radiation types are understood. This paper reports on simulations of TR and DR spatial-spectral characteristics using the physical optics propagation (POP mode of the Zemax advanced optics simulation software. A good consistency with theory is demonstrated. Also, realistic optical system alignment issues are discussed.

  3. Experimental observation and investigation of the prewave zone effect in optical diffraction radiation

    Directory of Open Access Journals (Sweden)

    P. Karataev

    2008-03-01

    Full Text Available Transition radiation (TR and diffraction radiation (DR has widely been used for both electron beam diagnostics and generation of intense radiation beams in the millimeter and the submillimeter wavelength range. Recently, it was theoretically predicted that TR and DR properties change either at extremely high energies of electrons or at long radiation wavelengths. This phenomenon was called a prewave zone effect. We have performed the first observation and detailed investigation of the prewave zone effect in optical diffraction radiation at 1.28 GeV electron beam at the KEK-Accelerator Test Facility (KEK-ATF. The beam energy at KEK-ATF is definitely not the highest one achieved in the world. Since we could easily observe the effect, at higher energies it might cause serious problems. We developed and applied a method for prewave zone suppression valid for optical wavelengths. Furthermore, a method for prewave zone suppression applicable for longer radiation wavelengths is discussed.

  4. LIGHT MODULATION: Wide-aperture diffraction of unpolarised radiation in a system of two acousto-optic filters

    Science.gov (United States)

    Magdich, L. N.; Yushkov, K. B.; Voloshinov, V. B.

    2009-04-01

    Light diffraction is studied in two tandem acousto-optic cells filtering unpolarised radiation with a wide angular spectrum. It is shown that the side lobes of the ultrasonic radiation pattern of a piezoelectric transducer produce side diffraction intensity maxima at the output of the system consisting of two filters. Diffraction in paratellurite filters is studied experimentally at 1.06 μm.

  5. 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.

  6. Overview of non-intercepting beam-size monitoring with optical diffraction radiation

    CERN Document Server

    Lumpkin, Alex H

    2012-01-01

    The initial demonstrations over the last several years of the use of optical diffraction radiation (ODR) as non-intercepting electron-beam-parameter monitors are reviewed. Developments in both far-field imaging and near-field imaging are addressed for ODR generated by a metal plane with a slit aperture, a single metal plane, and two-plane interferences. Polarization effects and sensitivities to beam size, divergence, and position will be discussed as well as a proposed path towards monitoring 10-micron beam sizes at 25 GeV.

  7. Overview of nonintercepting beam-size monitoring with optical diffraction radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, Alex H.; /Fermilab

    2010-08-01

    The initial demonstrations over the last several years of the use of optical diffraction radiation (ODR) as nonintercepting electron-beam-parameter monitors are reviewed. Developments in both far-field imaging and near-field imaging are addressed for ODR generated by a metal plane with a slit aperture, a single metal plane, and two-plane interferences. Polarization effects and sensitivities to beam size, divergence, and position will be discussed as well as a proposed path towards monitoring 10-micron beam sizes at 25 GeV.

  8. 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

  9. Conical diffraction effect in optical and x-ray Smith-Purcell radiation

    Directory of Open Access Journals (Sweden)

    D. Yu. Sergeeva

    2015-05-01

    Full Text Available Smith-Purcell radiation is a well-known phenomenon, which provides a noninvasive scheme for diagnostics of charged particle beams and is used as an effective source of electromagnetic waves, e.g., in the orotron, the free electron laser, etc. In this paper we develop the theory of Smith-Purcell radiation (SPR for the little-investigated case of arbitrary angles between the charged particle trajectories and the rulings of a grating. The effect of conical diffraction arising here changes drastically the space distribution of the radiation. By contrast to the only existing approach, described by Haeberle et al. [Phys. Rev. E 55, 4675 (1997], which requires difficult numerical calculations, we give a fully analytic theory of SPR. Also, in this paper we present for the first time the theory of x-ray Smith-Purcell radiation. Evanescent waves on the surface are shown to lead to strong enhancement of Smith-Purcell radiation, through a resonant mechanism. The results are important for the description of real divergent high-brightness beams and for the development of novel noninvasive diagnostic schemes based on the Smith-Purcell effect.

  10. 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

  11. Radiative properties of diffractively-coupled optical nano-antennas with helical geometry.

    Science.gov (United States)

    Wang, Ren; Forestiere, Carlo; Dal Negro, Luca

    2015-10-01

    In this paper, using the rigorous Surface Integral Equation (SIE) method, we study light scattering by Au nano-helices with geometrical dimensions comparable to the wavelength of visible light and we demonstrate that they behave as highly directional nano-antennas with largely controllable radiation and polarization characteristics in the optical regime. In particular, we systematically investigate the radiation properties of helical nano-antennas with realistic Au dispersion parameters in the visible spectral range, and we establish general design rules that enable the engineering of directional scattering with elliptical or circular polarization. Given the realistic material and geometric parameters used in this work, our findings provide novel opportunities for the engineering of chiral sensors, filters, and components for nano-scale antennas with unprecedented beam forming and polarization capabilities.

  12. 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...

  13. Field Guide to Diffractive Optics

    CERN Document Server

    Soskind, Yakov

    2011-01-01

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

  14. Development of a multipurpose vacuum chamber for serial optical and diffraction experiments with free electron laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rajkovic, I.; Hallmann, J.; Gruebel, S.; More, R.; Quevedo, W.; Petri, M.; Techert, S. [Department of Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, 37070 Goettingen (Germany)

    2010-04-15

    In this paper we present a development of a multipurpose vacuum chamber which primal function is to be used in pump/probe experiments with free electron laser (FEL) radiation. The chamber is constructed for serial diffraction and serial spectroscopy allowing a fast exchange of samples during the measurement process. For the fast exchange of samples, liquid jet systems are used. Both applications, utilizing soft x-ray FEL pulses as pump and optical laser pulses as probe and vice versa are documented. Experiments with solid samples as well as the liquid jet samples are presented. When working with liquid jets, a system of automatically refilled liquid traps for capturing liquids has been developed in order to ensure stable vacuum conditions. Differential pumping stages are placed in between the FEL beamline and the experimental chamber so that working pressure in the chamber can be up to four orders of magnitude higher than the pressure in the FEL beamline.

  15. Diffractive Optical Elements for Dynamic Optical Coupling

    Institute of Scientific and Technical Information of China (English)

    Changhe Zhou; Xin Zhao; Liren Liu

    2003-01-01

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

  16. Diffractive Optical Elements for Dynamic Optical Coupling

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

  17. 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.

  18. Transmissive Diffractive Optical Element Solar Concentrators

    Science.gov (United States)

    Baron, Richard; Moynihan, Philip; Price, Douglas

    2008-01-01

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

  19. Sub-wavelength diffractive optics

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-01

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

  20. 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.

  1. Diffractive Optics of Anisotropic Polarization Gratings

    NARCIS (Netherlands)

    Xu, M.

    2009-01-01

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

  2. Wedge Diffraction as an Instance of Radiative Shielding

    CERN Document Server

    Grzesik, J A

    2016-01-01

    The celebrated Sommerfeld wedge diffraction solution is reexamined from a null interior field perspective. Exact surface currents provided by that solution, when considered as disembodied half-plane laminae radiating into an ambient, uniform space both inside and outside the wedge proper, do succeed in reconstituting both a specular, mirror field above the exposed face, and a shielding plane-wave field of a sign opposite to that of the incoming excitation which, under superposition, creates both the classical, geometric-optics shadow, and a strictly null interior field at the dominant, plane-wave level. Both mirror and shadow radiated fields are controlled by the residue at just one simple pole encountered during a spectral radiative field assembly, fixed in place by incidence direction $\\phi_{0}$ as measured from the exposed face. The radiated fields further provide diffractive contributions drawn from two saddle points that track observation angle $\\phi.$ Even these, more or less asymptotic contributions, a...

  3. Geometrical optics and the diffraction phenomenon

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-06-30

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

  4. X-Ray Diffractive Optics

    Science.gov (United States)

    Dennis, Brian; Li, Mary; Skinner, Gerald

    2013-01-01

    X-ray optics were fabricated with the capability of imaging solar x-ray sources with better than 0.1 arcsecond angular resolution, over an order of magnitude finer than is currently possible. Such images would provide a new window into the little-understood energy release and particle acceleration regions in solar flares. They constitute one of the most promising ways to probe these regions in the solar atmosphere with the sensitivity and angular resolution needed to better understand the physical processes involved. A circular slit structure with widths as fine as 0.85 micron etched in a silicon wafer 8 microns thick forms a phase zone plate version of a Fresnel lens capable of focusing approx. =.6 keV x-rays. The focal length of the 3-cm diameter lenses is 100 microns, and the angular resolution capability is better than 0.1 arcsecond. Such phase zone plates were fabricated in Goddard fs Detector Development Lab. (DDL) and tested at the Goddard 600-microns x-ray test facility. The test data verified that the desired angular resolution and throughput efficiency were achieved.

  5. Resonant diffraction of synchrotron radiation: New possibilities

    Science.gov (United States)

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

    2016-09-01

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

  6. Optical image encryption based on diffractive imaging.

    Science.gov (United States)

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

    2010-11-15

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

  7. Diffraction limited optics for single atom manipulation

    CERN Document Server

    Sortais, Y R P; Browaeys, A; Fournet, P; Grangier, P; Lamare, M; Lance, A M; Marion, H; Mercier, R; Messin, G; Tuchendler, C

    2006-01-01

    We present an optical system designed to capture and observe a single neutral atom in an optical dipole trap, created by focussing a laser beam using a large numerical aperture N.A.=0.5 aspheric lens. We experimentally evaluate the performance of the optical system and show that it is diffraction limited over a broad spectral range (~ 200 nm) with a large transverse field (+/- 25 microns). The optical tweezer created at the focal point of the lens is able to trap single atoms of 87Rb and to detect them individually with a large collection efficiency. We measure the oscillation frequency of the atom in the dipole trap, and use this value as an independent determination of the waist of the optical tweezer. Finally, we produce with the same lens two dipole traps separated by 2.2 microns and show that the imaging system can resolve the two atoms.

  8. New approaches in diffraction based optical metrology

    Science.gov (United States)

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

    2016-03-01

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

  9. Integrated Diffractive Optics for Surface Ion Traps

    Science.gov (United States)

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

    2016-05-01

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

  10. Nuclear dynamical diffraction using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    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 {sup 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{plus_minus}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.

  11. Surface diffusion studies by optical diffraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, X.D.

    1992-11-01

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

  12. Diffraction radiation from relativistic heavy ions

    Science.gov (United States)

    Potylitsyna, N. A.

    2001-01-01

    In recent years, the relativistic heavy ion beams at new accelerator facilities are allowed to obtain some new interesting results (see, for instance, Datz et al., Phys. Rev. Lett. 79 (18) (1997) 3355; Ladyrin et al., Nucl. Instr. and Meth. A 404 (1998) 129). The problem of non-destructive heavy ion beam diagnostics at these accelerators is highly pressing. The authors of the papers (Rule et al., Proceedings of the Seventh Beam Instrumentation Workshop, Argonne IL, AIP Conference Proceedings, Vol. 390, NY, 1997; Castellano, Nucl. Instr. and Meth. A 394 (1997) 275) suggested to use diffraction radiation (DR) appearing when a charge moves close to a conducting surface (Bolotovskii and Voskresenskii, Sov. Phys. Usp. 9 (1966) 73) for non-destructive electron beam diagnostics. The DR characteristics are defined by both Lorentz-factor and the particle charge, and do not depend on its mass. The estimation of feasibility of using DR for relativistic ion beam diagnostics is undoubtedly interesting.

  13. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    Science.gov (United States)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  15. Flat hat glass diffractive optical beam shaper

    Science.gov (United States)

    Reichel, Steffen; Petzold, Uwe; Biertuempfel, Ralf; Vogt, Helge

    2009-02-01

    Many laser applications need a homogeneous - so called flat hat - light distribution in the application area. However, many laser emit Gaussian shaped light. The technology of diffractive optical elements (DOE) can be used to shape the Gaussian beam into a flat hat beam at a compact length. SCHOTT presents a DOE design of a flat hat DOE beam shaper made out of optical glass. Here the material glass has the significant advantage of high laser durability, low scattering losses, high resistance to temperature, moisture, and chemicals compared to polymer DOEs. Simulations and measurements on different DOEs for different wavelength, laser beam width, and laser divergence are presented. Surprisingly the flat hat DOE beam shaper depends only weakly on wavelength and beam width but strongly on laser divergence. Based on the good agreement between simulation and measurement an improved flat hat DOE beam shaper is also presented.

  16. Diffractive optical elements written by photodeposition

    Science.gov (United States)

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

    2003-03-01

    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.

  17. Diffractive optical elements written by photodeposition

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-03-15

    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 {mu}m wide lines of 200 nm thickness at rates of about 150 {mu}m/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.

  18. Optical properties of X-rays--dynamical diffraction.

    Science.gov (United States)

    Authier, André

    2012-01-01

    The first attempts at measuring the optical properties of X-rays such as refraction, reflection and diffraction are described. The main ideas forming the basis of Ewald's thesis in 1912 are then summarized. The first extension of Ewald's thesis to the X-ray case is the introduction of the reciprocal lattice. In the next step, the principles of the three versions of the dynamical theory of diffraction, by Darwin, Ewald and Laue, are given. It is shown how the comparison of the dynamical and geometrical theories of diffraction led Darwin to propose his extinction theory. The main optical properties of X-ray wavefields at the Bragg incidence are then reviewed: Pendellösung, shift of the Bragg peak, fine structure of Kossel lines, standing waves, anomalous absorption, paths of wavefields inside the crystal, Borrmann fan and double refraction. Lastly, some of the modern applications of the dynamical theory are briefly outlined: X-ray topography, location of adsorbed atoms at crystal surfaces, optical devices for synchrotron radiation and X-ray interferometry.

  19. Digital Diffractive Optics: An Introduction to Planar Diffractive Optics and Related Technology

    Science.gov (United States)

    Kress, B.; Meyrueis, P.

    2000-10-01

    Diffractive optical elements (DOEs) are becoming more and more widely used in a braod range of fields, including telecommunications, optical computing, consumer electronics, laser material processing and the biomedical sciences, to manipulate light through micro-optical systems. In order to get the most out of such DOEs, knowledge of the design process, fabrication, packaging in a particular system, and operation is required. Digital Diffractive Optics discusses in detail the design and simulation of DOEs, before considering the main fabrication techniques. The increasingly important CAD/CAM tool requirements for the production of DOEs are covered, and a chapter is devoted to the crucial area of systematic fabrication error compensation. Finally, the integration and use of DOEs in a number of different systems, including various opto-electronic and opto-mechanical systems, are discussed. Digital Diffractive Optics will be of great interest to all those involved in the fields of optical engineering and photonics. It presents a clear view of the whole process, from design to fabrication and application, without overstressing the, often complex, mathematics, and will thus be accessible to postgraduate students and those entering the field, as well as more experienced engineers and scientists.

  20. Information virtual indicator with combination of diffractive optical elements

    Science.gov (United States)

    Grad, Y. A.; Drozdova, E. A.; Nayden, L. A.; Nikolaev, V. V.; Odinokov, S. B.; Solomashenko, A. B.

    2016-08-01

    A combination of diffractive optical elements for monochrome information virtual indicators is described. To reduce the spectral "blurring" of image in monochrome indicators with OLED-display or LCD-display with LED backlight the possibility of using the volume reflection hologram as a spectral filter is investigated. The theoretical and experimental results show that the volume reflection hologram can be used as part of a monochrome virtual indicator containing OLED-, LCOS- or LCD-display with LED-backlight and relief-phase gratings for output of radiation from substrate to reduce the spectral "blurring" of image.

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

    Institute of Scientific and Technical Information of China (English)

    刘景

    2016-01-01

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

  2. Optical position encoder based on four-section diffraction grating

    Science.gov (United States)

    Zherdev, A. Y.; Odinokov, S. B.; Lushnikov, D. S.; Markin, V. V.; Gurylev, O. A.; Shishova, M. V.

    2017-05-01

    Optical position encoder consists of movable coding grating and fixed analyzing grating. Light passing and diffracting through these two gratings creates interference signal on optical detector. Decoding of interference signal phase allows to determinate current position. Known optical position encoders use several accurate adjusted optical channels and detectors to gather several signals with different phase for higher encoder accuracy. We propose to use one optical channel with several-section analyzing diffraction grating for this purpose to simplify optical scheme and adjusting requirements. Optical scheme of position encoder based on four-section analyzing diffraction grating is developed and described in this paper.

  3. Amplitude image processing by diffractive optics.

    Science.gov (United States)

    Cagigal, Manuel P; Valle, Pedro J; Canales, V F

    2016-02-22

    In contrast to the standard digital image processing, which operates over the detected image intensity, we propose to perform amplitude image processing. Amplitude processing, like low pass or high pass filtering, is carried out using diffractive optics elements (DOE) since it allows to operate over the field complex amplitude before it has been detected. We show the procedure for designing the DOE that corresponds to each operation. Furthermore, we accomplish an analysis of amplitude image processing performances. In particular, a DOE Laplacian filter is applied to simulated astronomical images for detecting two stars one Airy ring apart. We also check by numerical simulations that the use of a Laplacian amplitude filter produces less noisy images than the standard digital image processing.

  4. Virtual input device with diffractive optical element

    Science.gov (United States)

    Wu, Ching Chin; Chu, Chang Sheng

    2005-02-01

    As a portable device, such as PDA and cell phone, a small size build in virtual input device is more convenient for complex input demand. A few years ago, a creative idea called 'virtual keyboard' is announced, but up to now there's still no mass production method for this idea. In this paper we'll show the whole procedure of making a virtual keyboard. First of all is the HOE (Holographic Optical Element) design of keyboard image which yields a fan angle about 30 degrees, and then use the electron forming method to copy this pattern in high precision. And finally we can product this element by inject molding. With an adaptive lens design we can get a well correct keyboard image in distortion and a wilder fan angle about 70 degrees. With a batter alignment of HOE pattern lithography, we"re sure to get higher diffraction efficiency.

  5. Diffractive triangulation of radiative point sources

    CERN Document Server

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

    2016-01-01

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

  6. X-ray diffraction radiation in conditions of Cherenkov effect

    NARCIS (Netherlands)

    Tishchenko, A. A.; Potylitsyn, A. P.; Strikhanov, M. N.

    2006-01-01

    X-ray diffraction radiation from ultra-relativistic electrons moving near an absorbing target is considered. The emission yield is found to increase significantly in conditions of Cherenkov effect. (c) 2006 Elsevier B.V. All rights reserved.

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

    CERN Document Server

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

    2015-01-01

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

  8. 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...

  9. Introduction of acoustical diffraction in the radiative transfer method

    Science.gov (United States)

    Reboul, Emeline; Le Bot, Alain; Perret-Liaudet, Joël

    2004-07-01

    This Note presents an original approach to include diffraction in the radiative transfer method when applied to acoustics. This approach leads to a better spatial description of the acoustical energy. An energetic diffraction coefficient and some diffraction sources are introduced to model the diffraction phenomena. The amplitudes of these sources are determined by solving a linear sytem of equations resulting from the power balance between all acoustical sources. The approach is applied on bidimensional examples and gives good results except at geometrical boundaries. To cite this article: E. Reboul et al., C. R. Mecanique 332 (2004).

  10. Diffractive optical elements for transformation of modes in lasers

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-21

    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.

  11. Diffractive optics and micro-optics: introduction to the feature issue.

    Science.gov (United States)

    Magnusson, R; Gale, M T

    2001-11-10

    This issue of Applied Optics features 16 papers on the fabrication, design, and applications of diffractive optics and micro-optics. A companion issue of the Journal of the Optical Society of America A, guest edited by J. N. Mait and H. P. Herzig, presents papers that emphasize the modeling and design of diffractive and micro-optical components.

  12. Diffraction phenomena in spontaneous and stimulated radiation by relativistic particles in crystals (Review)

    Energy Technology Data Exchange (ETDEWEB)

    Baryshevsky, V.G. (Inst. of Nuclear Problems, Minsk (Belarus)); Dubovskaya, I.Ya. (Lawrence Berkeley Lab., CA (United States))

    1991-12-01

    This report discusses: the dispersion characteristics of parametric x-ray radiation (PXR) and diffraction radiation of oscillator; cooperative effects in x-radiation by charged particles in crystals; and diffraction x-radiation by relativistic oscillator.

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

    Science.gov (United States)

    Jing, Liu

    2016-07-01

    This article summarizes the developments of experimental techniques for high pressure x-ray diffraction (XRD) in diamond anvil cells (DACs) using synchrotron radiation. Basic principles and experimental methods for various diffraction geometry are described, including powder diffraction, single crystal diffraction, radial diffraction, as well as coupling with laser heating system. Resolution in d-spacing of different diffraction modes is discussed. More recent progress, such as extended application of single crystal diffraction for measurements of multigrain and electron density distribution, time-resolved diffraction with dynamic DAC and development of modulated heating techniques are briefly introduced. The current status of the high pressure beamline at BSRF (Beijing Synchrotron Radiation Facility) and some results are also presented. Project supported by the National Natural Science Foundation of China (Grant Nos. 10875142, 11079040, and 11075175). The 4W2 beamline of BSRF was supported by the Chinese Academy of Sciences (Grant Nos. KJCX2-SW-N20, KJCX2-SW-N03, and SYGNS04).

  14. 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.

  15. Computational imaging using lightweight diffractive-refractive optics.

    Science.gov (United States)

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

    2015-11-30

    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.

  16. Optical loss due to diffraction by concentrator Fresnel lenses

    Energy Technology Data Exchange (ETDEWEB)

    Hornung, Thorsten, E-mail: thorsten.hornung@ise.fraunhofer.de; Nitz, Peter, E-mail: thorsten.hornung@ise.fraunhofer.de [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany)

    2014-09-26

    Fresnel lenses are widely used in concentrating photovoltaic (CPV) systems as a primary optical element. They focus sunlight on small solar cells or on the entrance apertures of secondary optical elements. A Fresnel lens consists of several prism rings and diffraction by these prism rings is unavoidable. Some of the light that would reach a designated target area according to geometric optics will miss it due to diffraction. This diffraction loss may be of relevant magnitude for CPV applications. The results of published analytical calculations are evaluated, discussed, and compared to computer simulations and measurements.

  17. Diffraction and polarization effects in Earth radiation budget measurements.

    Science.gov (United States)

    Mahan, J R; Barki, A R; Priestley, K J

    2016-12-01

    Thermal radiation emitted and reflected from the Earth and viewed from near-Earth orbit may be characterized by its spectral distribution, its degree of coherence, and its state of polarization. The current generation of broadband Earth radiation budget instruments has been designed to minimize the effect of diffraction and polarization on science products. We used Monte Carlo ray-trace (MCRT) models that treat individual rays as quasi-monochromatic, polarized entities to explore the possibility of improving the performance of such instruments by including measures of diffraction and polarization during calibration and operation. We have demonstrated that diffraction and polarization sensitivity associated with typical Earth radiation budget instrument design features has a negligible effect on measurements.

  18. Optical systems for synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Howells, M.R.

    1985-12-01

    Various fundamental topics which underlie the design and use of optical systems for synchrotron radiation are considered from the viewpoint of linear system theory. These topics include the damped harmonic oscillator, free space propagation of an optical field, electromagnetic theory of optical properties of materials, theory of dispersion, and the Kramers-Kronig relations. 32 refs., 5 figs. (LEW)

  19. Encoded diffractive optics for full-spectrum computational imaging

    Science.gov (United States)

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

    2016-09-01

    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.

  20. 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.

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

    CERN Document Server

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ibison, M. [Liverpool University, Liverpool (United Kingdom); Cheung, K.C. [C.L.R.C. Daresbury Laboratory, Keckwick Lane, Daresbury, Cheshire WA4 4AD (United Kingdom); Siu, K. [Monash University, Melbourne, Victoria (Australia); Hall, C.J. [C.L.R.C. Daresbury Laboratory, Keckwick Lane, Daresbury, Cheshire WA4 4AD (United Kingdom)]. E-mail: c.j.hall@dl.ac.uk; Lewis, R.A. [Monash University, Melbourne, Victoria (Australia); Hufton, A. [Christie Hospital, Manchester (United Kingdom); Wilkinson, S.J. [Cranfield University, R.M.C.S., Shrivenham (United Kingdom); Rogers, K.D. [Cranfield University, R.M.C.S., Shrivenham (United Kingdom); Round, A. [C.L.R.C. Daresbury Laboratory, Keckwick Lane, Daresbury, Cheshire WA4 4AD (United Kingdom)

    2005-08-11

    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.

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

    Science.gov (United States)

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

    2005-08-01

    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.

  4. Monomer diffusion in sustainable photopolymers for diffractive optics applications

    OpenAIRE

    Gallego Rico, Sergi; Márquez Ruiz, Andrés; Ortuño Sánchez, Manuel; Marini, Stephan; Pascual Villalobos, Inmaculada; Beléndez Vázquez, Augusto

    2011-01-01

    Photopolymers have many applications in optics. However, one of the main drawbacks of these materials is the high toxicity of their components. One of the most widely studied photopolymers is polyvinyl-alcohol/acrylamide, and the carcinogenic potential of acrylamide is well known. In this paper we propose a new sustainable photopolymer as a substitute for acrylamide based photopolymers in the manufacture of diffractive optical elements. Diffraction efficiencies of around 40% were achieved for...

  5. Characteristic, parametric, and diffracted transition X-ray radiation for observation of accelerated particle beam profile

    Science.gov (United States)

    Chaikovska, I.; Chehab, R.; Artru, X.; Shchagin, A. V.

    2017-07-01

    The applicability of X-ray radiation for the observation of accelerated particle beam profiles is studied. Three types of quasi-monochromatic X-ray radiation excited by the particles in crystals are considered: characteristic X-ray radiation, parametric X-ray radiation, diffracted transition X-ray radiation. Radiation is collected at the right angle to the particle beam direction. It is show that the most intensive differential yield of X-ray radiation from Si crystal can be provided by characteristic radiation at incident electron energies up to tens MeV, by parametric radiation at incident electron energies from tens to hundreds MeV, by diffracted transition X-ray radiation at GeV and multi-GeV electron energies. Therefore these kinds of radiation are proposed for application to beam profile observation in the corresponding energy ranges of incident electrons. Some elements of X-ray optics for observation of the beam profile are discussed. The application of the DTR as a source of powerful tunable monochromatic linearly polarized X-ray beam excited by a multi-GeV electron beam on the crystal surface is proposed.

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

    Science.gov (United States)

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

    2016-05-01

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

  7. Optical laue diffraction on photonic structures designed by laser lithography

    Science.gov (United States)

    Samusev, K. B.; Rybin, M. V.; Lukashenko, S. Yu.; Limonov, M. F.

    2016-06-01

    Two-dimensional photonic crystals with square symmetry C 4v were obtained using the laser lithography method. The structure of these samples was studied by scanning electron microscopy. Optical Laue diffraction for monochromatic light was studied experimentally depending on the incidence angle of laser beam and lattice constant. Interpretation of the observed diffraction patterns is given in the framework of the Laue diffraction mechanism for an one-dimensional chain of scattering elements. Red thresholds for different diffraction orders were determined experimentally and theoretically. The results of calculations are in an excellent agreement with experiment.

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

    Science.gov (United States)

    Qin, Yi; Gong, Qiong; Wang, Zhipeng

    2014-09-08

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

  9. Super-resolution optical telescopes with local light diffraction shrinkage

    OpenAIRE

    Changtao Wang; Dongliang Tang; Yanqin Wang; Zeyu Zhao; Jiong Wang; Mingbo Pu; Yudong Zhang; Wei Yan; Ping Gao; Xiangang Luo

    2015-01-01

    Suffering from giant size of objective lenses and infeasible manipulations of distant targets, telescopes could not seek helps from present super-resolution imaging, such as scanning near-field optical microscopy, perfect lens and stimulated emission depletion microscopy. In this paper, local light diffraction shrinkage associated with optical super-oscillatory phenomenon is proposed for real-time and optically restoring super-resolution imaging information in a telescope system. It is found ...

  10. Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy.

    Science.gov (United States)

    Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; Nelson, Johanna; Shapiro, David; Stewart, Andrew; Turner, Joshua; Jacobsen, Chris

    2009-08-03

    Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution images using fewer photons. This can be an important advantage for studying radiation-sensitive biological and soft matter specimens.

  11. 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.

  12. Understanding the instrumental profile of synchrotron radiation X-ray powder diffraction beamlines.

    Science.gov (United States)

    Rebuffi, Luca; Sánchez Del Río, Manuel; Busetto, Edoardo; Scardi, Paolo

    2017-05-01

    A Monte Carlo algorithm has been developed to calculate the instrumental profile function of a powder diffraction synchrotron beamline. Realistic models of all optical elements are implemented in a ray-tracing software. The proposed approach and the emerging paradigm have been investigated and verified for several existing X-ray powder diffraction beamlines. The results, which can be extended to further facilities, show a new and general way of assessing the contribution of instrumental broadening to synchrotron radiation data, based on ab initio simulations.

  13. Application of optical diffraction method in designing phase plates

    Science.gov (United States)

    Lei, Ze-Min; Sun, Xiao-Yan; Lv, Feng-Nian; Zhang, Zhen; Lu, Xing-Qiang

    2016-11-01

    Continuous phase plate (CPP), which has a function of beam shaping in laser systems, is one kind of important diffractive optics. Based on the Fourier transform of the Gerchberg-Saxton (G-S) algorithm for designing CPP, we proposed an optical diffraction method according to the real system conditions. A thin lens can complete the Fourier transform of the input signal and the inverse propagation of light can be implemented in a program. Using both of the two functions can realize the iteration process to calculate the near-field distribution of light and the far-field repeatedly, which is similar to the G-S algorithm. The results show that using the optical diffraction method can design a CPP for a complicated laser system, and make the CPP have abilities of beam shaping and phase compensation for the phase aberration of the system. The method can improve the adaptation of the phase plate in systems with phase aberrations.

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

    Science.gov (United States)

    Qin, Yi; Wang, Zhipeng; Gong, Qiong

    2014-07-01

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

  15. Quantum optical dipole radiation fields

    CERN Document Server

    Stokes, Adam

    2016-01-01

    We introduce quantum optical dipole radiation fields defined in terms of photon creation and annihilation operators. These fields are identified through their spatial dependence, as the components of the total fields that survive infinitely far from the dipole source. We use these radiation fields to perturbatively evaluate the electromagnetic radiated energy-flux of the excited dipole. Our results indicate that the standard interpretation of a bare atom surrounded by a localised virtual photon cloud, is difficult to sustain, because the radiated energy-flux surviving infinitely far from the source contains virtual contributions. It follows that there is a clear distinction to be made between a radiative photon defined in terms of the radiation fields, and a real photon, whose identification depends on whether or not a given process conserves the free energy. This free energy is represented by the difference between the total dipole-field Hamiltonian and its interaction component.

  16. Photodeposited diffractive optical elements of computer generated masks

    Energy Technology Data Exchange (ETDEWEB)

    Mirchin, N. [Electrical and Electronics Engineering Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel)]. E-mail: mirchin@hait.ac.il; Peled, A. [Electrical and Electronics Engineering Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel); Baal-Zedaka, I. [Electrical and Electronics Engineering Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel); Margolin, R. [Electrical and Electronics Engineering Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel); Zagon, M. [Electrical and Electronics Engineering Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel); Lapsker, I. [Physics Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel); Verdyan, A. [Physics Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel); Azoulay, J. [Physics Department, Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel)

    2005-07-30

    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.

  17. Photodeposited diffractive optical elements of computer generated masks

    Science.gov (United States)

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

    2005-07-01

    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.

  18. Optics and radiators for RICH

    CERN Document Server

    Ekelöf, T J C

    1999-01-01

    An overview is given of the basic optics-design principles for Ring Imaging Cherenkov (RICH) counters in High-Energy Physics -- of the earlier evolution of these principles and of the new ideas and techniques that are currently being developed. The characteristics of the different gasses, liquids and solids that are employed as Cherenkov radiators, which are of fundamental importance to the optics design of a RICH counter, are also reviewed.

  19. Optical diffraction for measurements of nano-mechanical bending

    CERN Document Server

    Hermans, Rodolfo I; Ndieyira, Joseph Wafula; McKendry, Rachel A; Aeppli, Gabriel

    2015-01-01

    Micromechanical transducers such as cantilevers for AFM often rely on optical readout methods that require illumination of a specific region of the microstructure. Here we explore and exploit the diffraction effects that have been previously neglected when modeling cantilever bending measurement techniques. The illumination of a cantilever end causes an asymmetric diffraction pattern at the photodetector that significantly affects the calibration of the signal in the popular optical beam deflection technique (OBDT). Conditions for optimized linear signals that avoid detection artifacts conflict with small numerical aperture illumination and narrow cantilevers which are softer and therefore more sensitive. Embracing diffraction patterns as a physical measurable allows a richer detection technique that decouples measurements of tilt and curvature and simultaneously relaxes the requirements on the alignment of illumination and detector. We show analytical results, numerical simulations and physiologically releva...

  20. 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.)

  1. Electro-optically tunable diffraction grating with photoaligned liquid crystals

    Science.gov (United States)

    Węgłowski, Rafał; Kozanecka-Szmigiel, Anna; Piecek, Wiktor; Konieczkowska, Jolanta; Schab-Balcerzak, Ewa

    2017-10-01

    This work shows the possibility of fabricating one- and two-dimensional diffraction structures based on liquid crystals photoaligned with the layers of photosensitive azobenzene poly(ester imide). The gratings involve a micron-sized planar-twisted nematic alignment. The diffraction efficiency of these gratings is controlled by a uniform electric field applied across the cell. The electro-optical measurements showed short switching times (0.8 ms and 7 ms for τrise and τdecay respectively) and low driving electric fields (1 . 5 V / μm) of 1st order diffracted light. The LC grating is regarded as an amplitude grating in the low electric field region and a phase grating in the high electric field region. Moreover the diffraction efficiency is polarization-independent in the wide range of external electric fields.

  2. Fiber-diffraction Interferometer using Coherent Fiber Optic Taper

    CERN Document Server

    Kihm, Hagyong

    2010-01-01

    We present a fiber-diffraction interferometer using a coherent fiber optic taper for optical testing in an uncontrolled environment. We use a coherent fiber optic taper and a single-mode fiber having thermally-expanded core. Part of the measurement wave coming from a test target is condensed through a fiber optic taper and spatially filtered from a single-mode fiber to be reference wave. Vibration of the cavity between the target and the interferometer probe is common to both reference and measurement waves, thus the interference fringe is stabilized in an optical way. Generation of the reference wave is stable even with the target movement. Focus shift of the input measurement wave is desensitized by a coherent fiber optic taper.

  3. Diffractive Optics: Design, Fabrication, and Applications, Technical Digest Series, Volume 9, 1992

    Science.gov (United States)

    1992-01-01

    Diffractive TuA, DIFFRACTIVE OPTICS FOR LASER SYSTEMS and refractive microlenses are combined to obtain improved Norbert Streibl, University Erlangen...wave linear diode-laser array into a two-dimensional distribution analysis of grating diffraction, Elias N. Glytsis, Thomas K. with symmetric...Diffractive optical elements in optoelectronics, Norbert Streibl, Physikalisches Institut, Germany. Diffractive components such as deflectors, lenses and

  4. Optical filters with fractal transmission spectra based on diffractive optics.

    Science.gov (United States)

    Mendoza-Yero, Omel; Mínguez-Vega, Gladys; Fernández-Alonso, Mercedes; Lancis, Jesús; Tajahuerce, Enrique; Climent, Vicent; Monsoriu, Juan A

    2009-03-01

    The duality between the axial irradiance distribution originated by any circularly symmetric diffracting aperture under monochromatic illumination and its diffracted spectral intensity at a fixed on-axis point under broadband illumination is highlighted and experimentally investigated. Two applications are derived from this basic result. On the one hand, we suggest the use of a broadband source and a spectrometer for a single-shot measurement of the axial response of pupil filters. Second, we implement a spectral filter having a transmission spectrum with a fractal structure of frequencies. Experimental results and potential applications in synthetic spectra designs are provided.

  5. Optical diffraction for measurements of nano-mechanical bending

    Science.gov (United States)

    Hermans, Rodolfo I.; Dueck, Benjamin; Ndieyira, Joseph Wafula; McKendry, Rachel A.; Aeppli, Gabriel

    2016-06-01

    We explore and exploit diffraction effects that have been previously neglected when modelling optical measurement techniques for the bending of micro-mechanical transducers such as cantilevers for atomic force microscopy. The illumination of a cantilever edge causes an asymmetric diffraction pattern at the photo-detector affecting the calibration of the measured signal in the popular optical beam deflection technique (OBDT). The conditions that avoid such detection artefacts conflict with the use of smaller cantilevers. Embracing diffraction patterns as data yields a potent detection technique that decouples tilt and curvature and simultaneously relaxes the requirements on the illumination alignment and detector position through a measurable which is invariant to translation and rotation. We show analytical results, numerical simulations and physiologically relevant experimental data demonstrating the utility of the diffraction patterns. We offer experimental design guidelines and quantify possible sources of systematic error in OBDT. We demonstrate a new nanometre resolution detection method that can replace OBDT, where diffraction effects from finite sized or patterned cantilevers are exploited. Such effects are readily generalized to cantilever arrays, and allow transmission detection of mechanical curvature, enabling instrumentation with simpler geometry. We highlight the comparative advantages over OBDT by detecting molecular activity of antibiotic Vancomycin.

  6. Radiation damage free two-color X-ray ghost diffraction with atomic resolution

    CERN Document Server

    Li, Zheng; Chapman, Henry; Shih, Yanhua

    2015-01-01

    The X-ray free electron lasers (XFEL) can enable diffractive structural determination of protein crystals or single molecules that are too small and radiation-sensitive for conventional X-ray analysis. However the electronic form factor could have been modified during the ultrashort X-ray pulse due to photoionization and electron cascade caused by the intense X-ray pulse. For general X-ray imaging techniques, to minimize radiation damage effect is of major concern to ensure faithful reconstruction of the structure. Here we show that a radiation damage free diffraction can be achieved with an atomic spatial resolution, by using X-ray parametric down-conversion (PDC), and two-color biphoton ghost imaging. We illustrate that formation of the diffractive patterns satisfies a condition analogous to the Bragg equation, with a resolution that could be as fine as the lattice length scale of several Angstrom. Because the samples are illuminated by the optical photons of low energy, they can be free of radiation damage...

  7. 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...... 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....... 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...

  8. 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.

  9. Optical method for inspecting LSI patterns using reflected diffraction waves.

    Science.gov (United States)

    Kimura, S; Suda, K; Hase, S; Munakata, C

    1988-03-15

    An optical inspection method has been developed for finding defects in LSI lithographic patterns. A focused He-Ne laser beam scans the patterns on a wafer. The reflected diffraction waves around the wafer are observed. These diffraction waves indicate whether the patterns contain defects. To implement this judgment rapidly, signals of the waves characterizing the patterns are input directly into the address lines of random access memories. The system can detect a defect of ~0.8-microm diameter and inspect a 1-cm(2) chip in 9 s.

  10. Non-diffracting chirped Bessel waves in optical antiguides

    CERN Document Server

    Chremmos, Ioannis

    2015-01-01

    Chirped Bessel waves are introduced as stable (non-diffracting) solutions of the paraxial wave equation in optical antiguides with a power-law radial variation in their index of refraction. Through numerical simulations, we investigate the propagation of apodized (finite-energy) versions of such waves, with or without vorticity, in antiguides with practical parameters. The new waves exhibit a remarkable resistance against the defocusing effect of the unstable index potentials, outperforming standard Gaussians with the same full width at half maximum. The chirped profile persists even under conditions of eccentric launching or antiguide bending and is also capable of self-healing like standard diffraction-free beams in free space.

  11. Compact sorting of optical vortices by means of diffractive transformation optics

    OpenAIRE

    Ruffato, Gianluca; Massari, Michele; Romanato, Filippo

    2016-01-01

    The orbital angular momentum (OAM) of light has recently attracted a growing interest as a new degree of freedom in order to increase the information capacity of today optical networks both for free-space and optical fiber transmission. Here we present our work of design, fabrication and optical characterization of diffractive optical elements for compact OAM-mode division demultiplexing based on optical transformations. Samples have been fabricated with 3D high-resolution electron beam litho...

  12. Emittance Adapter for a Diffraction Limited Synchrotron Radiation Source

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alexander Wu; /SLAC; Raimondi, Pantaleo; /Frascati

    2012-03-01

    We investigate the possibility of reaching very small horizontal and vertical emittances inside an undulator in a storage ring, by means of a local exchange of the apparent horizontal and vertical emittances, performed with a combination of skew quadrupoles and one solenoid in a dedicated insertion line in the storage ring. The insertion leaves the ring parameters and its optical properties unaffected. This scheme could greatly relax the emittance requirements for a diffraction limited synchrotron light source. The lattice derivation and design is described.

  13. Super-resolution optical telescopes with local light diffraction shrinkage

    Science.gov (United States)

    Wang, Changtao; Tang, Dongliang; Wang, Yanqin; Zhao, Zeyu; Wang, Jiong; Pu, Mingbo; Zhang, Yudong; Yan, Wei; Gao, Ping; Luo, Xiangang

    2015-12-01

    Suffering from giant size of objective lenses and infeasible manipulations of distant targets, telescopes could not seek helps from present super-resolution imaging, such as scanning near-field optical microscopy, perfect lens and stimulated emission depletion microscopy. In this paper, local light diffraction shrinkage associated with optical super-oscillatory phenomenon is proposed for real-time and optically restoring super-resolution imaging information in a telescope system. It is found that fine target features concealed in diffraction-limited optical images of a telescope could be observed in a small local field of view, benefiting from a relayed metasurface-based super-oscillatory imaging optics in which some local Fourier components beyond the cut-off frequency of telescope could be restored. As experimental examples, a minimal resolution to 0.55 of Rayleigh criterion is obtained, and imaging complex targets and large targets by superimposing multiple local fields of views are demonstrated as well. This investigation provides an access for real-time, incoherent and super-resolution telescopes without the manipulation of distant targets. More importantly, it gives counterintuitive evidence to the common knowledge that relayed optics could not deliver more imaging details than objective systems.

  14. New approach to imaging spectroscopy using diffractive optics

    Science.gov (United States)

    Hinnrichs, Michele; Massie, Mark A.

    1997-10-01

    Over the past several years, Pacific Advanced Technology (PAT) has developed several hyperspectral imagers using diffractive optics as the dispersive media. This new approach has been patented and demonstrated in numerous field tests. PAT has developed hyperspectral cameras in the visible, mid-wave IR and is currently under contrast to the Air Force to develop a dual band hyperspectral lens for simultaneous spectral imaging in both the mid-wave and long- wave IR. The development of these cameras over the years have been sponsored by internal research and development, contracts from the Air Force Phillips Lab., Air Force Wright Labs Armament Division, BMDO and by the Office of Naval Research. Numerous papers have been presented in the past describing the performance of these various hyperspectral cameras. The purpose of this paper is to describe the theory behind the image multi-spectral sensing (IMSS) used in these hyperspectral cameras. IMSS utilizes a very simple optical design that enables a robust and low cost hyper-spectral imaging instrument. The IMSS is a dispersive spectrometer using a single diffractive optical element for both imaging and dispersion. The lens is tuned for a single wavelength giving maximum diffraction efficiency at that wavelength and high efficiency throughout the spectral band-pass of the camera. The diffractive optics disperse the light along the optical axis as opposed to perpendicular to the axis in conventional dispersive spectrometers. A detector array is used as the sensing medium and the spectral images are rad out electronically. POst processing is used to reduce spectral cross talk and to spatially sharpen the spectral images.

  15. Fiber optic ionizing radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Suter, J.J. (Johns Hopkins Univ., Applied Physics Lab., Laurel, MD (United States)); Poret, J.C.; Rosen, M. (Johns Hopkins Univ., Dept. of Materials Science and Engineering, Baltimore, MD (United States))

    1992-08-01

    Radiation detection can be done by various types of devices, such as Geiger counters, thermoluminescent detectors, and electric field sensors. This paper reports on a noel design for an ionizing radiation sensor using coiled optical fibers, which can be placed within or near a radioactive source. This design has several features that make it different from sensors proposed in the past. In order to evaluate this sensor, coiled fiber samples were placed inside metallic and metal-matrix composite cylinders to evaluate the sensitivity of the detector as well as the shielding effectiveness of the materials.

  16. Linear systems approach to simulation of optical diffraction.

    Science.gov (United States)

    Lambert, A J; Fraser, D

    1998-12-01

    The diffractive processes within an optical system can be simulated by computer to compute the diffraction-altered electric-field distribution at the output of the system from the electric-field distribution at the input. In the paraxial approximation the system can be described by an ABCD ray matrix whose elements in turn can be used to simplify the computation such that only a single computational step is required. We describe two rearrangements of such computations that allow the simulation to be expressed in a linear systems formulation, in particular using the fast-Fourier-transform algorithm. We investigate the sampling requirements for the kernel-modifying function or chirp that arises. We also use the special properties of the chirp to determine the spreading imposed by the diffraction. This knowledge can be used to reduce the computation if only a limited region of either the input or the output is of interest.

  17. Sub-diffraction-Limit Imaging in Optical Hyperlens

    Institute of Scientific and Technical Information of China (English)

    HU Ji-Gang; WANG Pei; LU Yong-Hua; MING Hai; CHEN Chun-Chong; CHEN Jun-Xue

    2008-01-01

    @@ Sub-diffraction-limit imaging in the optical hyperlens based on cylindrical metamaterials is studied. Some param-eters of hyperlens, such as the dispersive relation and the divergence angle of imaging, are numerically analysed with the ray trajectory method and effective medium theory. The dependence of imaging properties on dielectric constant is discussed. As a result, a 0° divergence angle is obtained for the best imaging effect. This work will be helpful for the design, structure fabrication and resolution improvement of the optical hyperlens.

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

    CERN Document Server

    Nixon, Sean

    2013-01-01

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

  19. Traceability of high focal length cameras with diffractive optical elements

    Science.gov (United States)

    Lages Martins, L.; Silva Ribeiro, A.; Sousa, J. Alves e.

    2016-11-01

    This paper describes the use of diffractive optical elements (DOEs) for metrological traceable geometrical testing of high focal length cameras applied in the observation of large- scale structures. DOEs and related mathematical models are briefly explained. Laboratorial activities and results are described for the case of a high focal length camera used for longdistance displacement measurement of a long-span (2278 m) suspension bridge.

  20. Teaching diffraction with hands-on optical spectrometry

    Science.gov (United States)

    Fischer, Robert

    2012-09-01

    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 low-cost materials. The spectrometer’s simple, didactic design allows students to fully comprehend the underlying physical concepts and to engage in a discussion of measurement errors and uncertainties.

  1. Optical diffraction of fractal figures: random Sierpinski carpets

    Science.gov (United States)

    Berger, Denise; Chamaly, Stéphane; Perreau, Michel; Mercier, Daniel; Monceau, Pascal; Levy, Jean-Claude Serge

    1991-10-01

    The optical diffraction patterns of random Sierpinski carpets of different fractal dimensions at different levels of iteration are shown and analyzed. The sensitivity of such an analysis to long range correlations, is demonstrated theoretically by means of the transfer matrix formalism of fractals, T.M.F. The relation between the subdimensions defined in T.M.F. and diffraction patterns is outlined. Finally an analysis of experimental diffraction patterns is proposed in order to measure these new theoretical subdimensions. On présente ici les clichés de diffraction optique de tapis de Sierpinski aléatoires de différentes dimensions fractales, pris à des niveaux d'itération différents. Au moyen du formalisme de la matrice de transfert dans les fractals, on montre la sensibilité de cette analyse expérimentale aux corrélations à moyenne et longue portée. Ainsi la relation entre les sous-dimensions fractales du F.M.T. et les rapports d'intensité entre les clichés de diffraction de figures fractales à des niveaux d'itération différents est soulignée. Enfin on esquisse le principe d'une analyse expérimentale de ces nouvelles dimensions théoriques.

  2. X-ray magnetic diffraction of ferromagnets with synchrotron radiation

    CERN Document Server

    Ito, M

    2002-01-01

    X-ray magnetic diffraction experiment of ferromagnets that utilizes elliptically polarized synchrotron radiation is presented. First we have reviewed shortly historical backgrounds and theoretical aspects of the experiment. We have presented how the magnetic form factors are measured and are separated into the spin-moment component and the orbital-moment component in this experiment. Peculiar features of the polarization factor of this experiment have been explained. We have introduced two examples of the experiment. One is the measurement of the spin-magnetic form factor of SmAl sub 2 with white X-rays from a bending magnet at the Photon Factory. The other is the measurement of the orbital-magnetic form factor of Holmium Iron Garnets with monochromatic X-rays from an undulator at the SPring-8. Finally we summarize the article and show some future prospects of this experiment. (author)

  3. LINC-NIRVANA: cryogenic optics for diffraction limited beam combination

    Science.gov (United States)

    Bizenberger, Peter; Baumeister, Harald; Herbst, Tom; Zhang, Xianyu

    2012-09-01

    LINC-NIRVANA is an interferometric imaging camera, which combines the two 8.4 m telescopes of the Large Binocular Telescope (LBT). The instrument operates in the wavelength range from 1.1 μm to 2.4 μm, covering the J, H and K-band, respectively. The beam combining camera (NIRCS) offers the possibility to achieve diffraction limited images with the special resolution of a 23 m telescope. The optics are designed to deliver a 10 arcsec × 10 arcsec field of view with 5 mas resolution. In this paper we describe the evolution of the cryogenic optics, from design and manufacturing to verification. Including the argumentation for decisions we made in order to present a sort of guideline for large cryo-optics. We also present the alignment and testing strategies at a detailed level.

  4. Compact sorting of optical vortices by means of diffractive transformation optics

    CERN Document Server

    Ruffato, Gianluca; Romanato, Filippo

    2016-01-01

    The orbital angular momentum (OAM) of light has recently attracted a growing interest as a new degree of freedom in order to increase the information capacity of today optical networks both for free-space and optical fiber transmission. Here we present our work of design, fabrication and optical characterization of diffractive optical elements for compact OAM-mode division demultiplexing based on optical transformations. Samples have been fabricated with 3D high-resolution electron beam lithography on polymethylmethacrylate (PMMA) resist layer spun over a glass substrate. Their high compactness and efficiency make these optical devices promising for integration into next-generation platforms for OAM-modes processing in telecom applications.

  5. Analysis of LCoS displays performance in diffractive optics

    Science.gov (United States)

    Lizana, A.; Lobato, L.; Iemmi, C.; Márquez, A.; Moreno, I.; Campos, J.; Yzuel, M. J.

    2010-06-01

    In this paper, we describe the Mueller-Jones combined method which is useful to optimize the LCoS displays phase response. This method, by means of the experimentally obtained Mueller matrices of the device, enables to obtain pairs of states of polarization (for the generation and for the detection states), which lead to the phase-only modulation regime. Moreover, some experimental results are provided as a function of the incident angle, wavelength and gray level. In addition, we also show the strong dependence of the LCoS performance with the signal addressed to the device, which affects the value of different physical parameters, such as the global phase-shift or the time-fluctuations in phase. Retardance curve and time-fluctuations in phase for the different sequences studied are obtained from the experimental Mueller matrices (the former) and by using a diffractive based set-up (the latter). The efficiency of basic diffractive optical elements is tested with the LCoS display, emphasizing the suitability of the best electrical sequence found when used in diffractive optics.

  6. Localizer with high occlusion immunity using diffraction optics

    Science.gov (United States)

    Ditto, Thomas D.; Farges, Jacques

    2004-10-01

    The chromatic method of diffraction range finding can be exploited to construct a 3D localizer that tracks the position of a pointer, a 3-D scanner or a robotic end-effecter. A spectrogram is made using a diffraction grating as the primary objective of an optical system that tracks a broad band emitter such as a tungsten filament or white L.E.D. Image processing on the resulting spectra transforms the spectrogram at the input to distance and displacement at the output. The behavior conforms to geometric optics following the Diffraction Equation. This novel technique has unique features. For example, the number of samples increases with target distance, reversing the loss of resolution as a function of distance that is endemic to triangulation. The plurality of samples also can overcome occlusion liability common to time-of-flight range finders, since multiple paths exist between emitter and sensor. The grating can be made from inexpensive embossed plastic, and a wave length sensor can be constructed from garden variety color cameras. The method is robust at a grazing exodus angles that allow for a compact configuration of the receiver. In this paper we disclose the theory of operation including a mathematical model, and we demonstrate the method empirically.

  7. Computer simulation of diffractive optical element (DOE) performance

    Science.gov (United States)

    Delacour, Jacques F.; Venturino, Jean-Claude; Gouedard, Yannick

    2004-02-01

    Diffractive optical elements (DOE), also known as computer generated holograms (CGH), can transform an illuminating laser beam into a specified intensity distribution by diffraction rather than refraction or reflection. These are widely used in coherent light systems with beam shaping purposes, as an alignment tool or as a structured light generator. The diffractive surface is split into an array of sub-wavelength depth cells. Each of these locally transforms the beam by phase adaptation. Based on the work of the LSP lab from the University of Strasbourg, France, we have developed a unique industry-oriented tool. It allows the user first to optimize a DOE using the Gerchberg-Saxton algorithm. This part can manage sources from the simple plane wave to high order Gaussian modes or complex maps defined beams and objective patterns based on BMP images. A simulation part permits then to test the performance of the DOE with regard to system parameters, dealing with the beam, the DOE itself and the system organization. This will meet the needs of people concerned by tolerancing issues. Focusing on the industrial problem of beam shaping, we will present the whole DOE design sequence, starting from the generation of a DOE up to the study of the sensitivity of its performance according to the variation of several parameters of the system. For example, we will show the influence of the position of the beam on diffraction efficiency. This unique feature formerly neglected in industrial design process will lead the way to production quality improvement.

  8. LINC-NIRVANA: Diffraction limited optics in cryogenic environment

    Science.gov (United States)

    Bizenberger, Peter; Baumeister, Harald; Fopp, Patrick; Herbst, Tom; Laun, Werner; Mohr, Lars; Moreno-Ventas, Javier

    2014-07-01

    LINC-NIRVANA is an instrument combining the two 8.4 m telescopes of the Large Binocular Telescope (LBT) coherently, in order to achieve the optical resolution of the 23 meter baseline. For this interferometric instrument concept, the common beam combination requires diffraction limited optical performance. The optics, realized as a Cassegrain telescope design, consists of aluminum mirrors, designed and manufactured to fulfill the challenging specifications required for interferometric imaging. Due to the science wavelength range from 1 μm to 2.4 μm, covering the J, H and K band of the atmosphere, the complete beam combiner including the optics is operated in cryogenic environment at 60 Kelvin. Here, we demonstrate the verification of the optical performance at this temperature for classical in-coherent and coherent illumination. We outline the test setup and present the achieved results of wavefront error for the individual beams and fringe contrast for the interferometric point spread function. This paper continues the already presented integration of the interferometric camera with the focus on the performance of the cryogenic optics.

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

    Science.gov (United States)

    Maddox, B R; Akin, M C; Teruya, A; Hunt, D; Hahn, D; Cradick, J; Morgan, D V

    2016-08-01

    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(7) molybdenum Kα photons.

  10. High throughput optoelectronic smart pixel systems using diffractive optics

    Science.gov (United States)

    Chen, Chih-Hao

    1999-12-01

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

  11. Coherent forward and backward diffraction radiation of relativistic electrons in a dielectric targets

    Science.gov (United States)

    Naumenko, G. A.; Shevelev, M. V.; Popov, Yu A.

    2016-08-01

    During the interaction of the relativistic electrons field with a dielectric target various types of electromagnetic radiation, such as Cerenkov radiation, diffraction radiation, transition radiation can be generated. In this report we present the results of experimental studies of the diffraction radiation generated by relativistic electrons in a dielectric target at the interface vacuum-insulator and insulator-conductor in the millimeter wavelength range. The experimental results show that the component of the diffraction radiation of relativistic electrons at the interface insulator-conductor, for any significant refractive index of insulator, is suppressed. The analysis of the results from different points of view was done.

  12. 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.

  13. 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.

  14. 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.

  15. Optical diffraction tomography techniques for the study of cell pathophysiology

    CERN Document Server

    Kim, Kyoohyun; Shin, Seungwoo; Lee, SangYun; Yang, Su-A; Park, YongKeun

    2016-01-01

    Three-dimensional imaging of biological cells is crucial for the investigation of cell biology, provide valuable information to reveal the mechanisms behind pathophysiology of cells and tissues. Recent advances in optical diffraction tomography (ODT) have demonstrated the potential for the study of various cells with its unique advantages of quantitative and label-free imaging capability. To provide insight on this rapidly growing field of research and to discuss its applications in biology and medicine, we present the summary of the ODT principle and highlight recent studies utilizing ODT with the emphasis on the applications to the pathophysiology of cells.

  16. 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...... and numerical investigations of finite-length surface-relief structures embedded in polymer dielectric waveguiding materials are presented. The importance of several geometric parameter dependencies is indicated as far-field power distributions are rearranged between diffraction orders. The influences...

  17. Microbial Diffraction Gratings as Optical Detectors for Heavy Metal Pollutants

    Science.gov (United States)

    Noever, David; Matsos, Helen; Brittain, Andrew; Obenhuber, Don; Cronise, Raymond; Armstrong, Shannon

    1996-01-01

    As a significant industrial pollutant, cadmium is implicated as the cause of itai-itai disease. For biological detection of cadmium toxicity, an assay device has been developed using the motile response of the protozoa species, Tetrahymena pyriformis. This mobile protozoa measures 50 microns in diameter, swims at 10 body lengths per second, and aggregates into macroscopically visible patterns at high organism concentrations. The assay demonstrates a Cd(+2) sensitivity better than 1 micro-M and a toxicity threshold to 5 micro-M, thus encouraging the study of these microbial cultures as viable pollution detectors. Using two-dimensional diffraction patterns within a Tetrahymena culture, the scattered light intensity varies with different organism densities (population counts). The resulting density profile correlates strongly with the toxic effects at very low dosages for cadmium (less than 5 ppm) and then for poison protection directly (with nickel and copper antagonists competing with cadmium absorption). In particular, copper dosages as low as 0.1-0.5 mM Cu have shown protective antagonism against cadmium, have enhanced density variability for cultures containing 1 mM Cd(+2) and therefore have demonstrated the sensitivity of the optical detection system. In this way, such microbial diffraction patterns give a responsive optical measure of biological culture changes and toxicity determination in aqueous samples of heavy metals and industrial pollutants.

  18. Nanofabrication and test of novel diffractive optics for OAM-mode division multiplexing in optical fibers

    Science.gov (United States)

    Ruffato, G.; Massari, M.; Romanato, F.

    2016-09-01

    The orbital angular momentum (OAM) of light offers a promising solution to today's overwhelming demand of bandwidth and has known an increasing attention as a new degree of freedom in the telecom field. Here we present the design, fabrication and optical characterization of miniaturized phase-only diffractive optical elements (DOE) for OAM beams generation, multiplexing and sorting. Samples have been fabricated with high-resolution electron-beam lithography and exhibit high fabrication quality. Different DOE designs are presented for the sorting of optical vortices with different steering geometries in far-field and applications in free-space and optical fibers.

  19. Spin-to-orbit conversion at acousto-optic diffraction of light: conservation of optical angular momentum.

    Science.gov (United States)

    Skab, Ihor; Vlokh, Rostyslav

    2012-04-01

    Acousto-optic diffraction of light in optically active cubic crystals is analyzed from the viewpoint of conservation of optical angular momentum. It is shown that the availability of angular momentum in the diffracted optical beam can be necessarily inferred from the requirements of angular momentum conservation law. As follows from our analysis, a circularly polarized diffracted wave should bear an orbital angular momentum. The efficiency of the spin-to-orbit momentum conversion is governed by the efficiency of acousto-optic diffraction.

  20. Fast character projection electron beam lithography for diffractive optical elements

    Science.gov (United States)

    Harzendorf, Torsten; Fuchs, Frank; Banasch, Michael; Zeitner, Uwe D.

    2014-05-01

    Electron beam lithography becomes attractive also for the fabrication of large scale diffractive optical elements by the use of the character projection (CP) technique. Even in the comparable fast variable shaped beam (VSB) exposure approach for conventional electron beam writers optical nanostructures may require very long writing times exceeding 24 hours per wafer because of the high density of features, as required by e.g. sub-wavelength nanostructures. Using character projection, the writing time can be reduced by more than one order of magnitude, due to the simultaneous exposure of multiple features. The benefit of character projection increases with increasing complexity of the features and decreasing period. In this contribution we demonstrate the CP technique for a grating of hexagonal symmetry at 350nm period. The pattern is designed to provide antireflective (AR) properties, which can be adapted in their spectral and angular domain for applications from VIS to NIR by changing the feature size and the etching depth of the nanostructure. This AR nanostructure can be used on the backside of optical elements e.g. gratings, when an AR coating stack could not be applied for the reason of climatic conditions or wave front accuracy.

  1. 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.

  2. 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.

  3. Test of mode-division multiplexing and demultiplexing in free-space with diffractive transformation optics

    OpenAIRE

    Ruffato, Gianluca; Massari, Michele; Parisi, Giuseppe; Romanato, Filippo

    2016-01-01

    In recent years, mode-division multiplexing (MDM) has been proposed as a promising solution in order to increase the information capacity of optical networks both in free-space and in optical fiber transmission. Here we present the design, fabrication and test of diffractive optical elements for mode-division multiplexing based on optical transformations in the visible range. Diffractive optics have been fabricated by means of 3D high-resolution electron beam lithography on polymethylmethacry...

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

    Science.gov (United States)

    2015-03-26

    Large optical photon sieve,” Optics Letters , 30(22): 2976-2978 (November 2005). 2. Andersen, Geoff. Senior Researcher, Laser and Optics ...EFFECTS USING SECOND-STAGE DIFFRACTIVE OPTICS THESIS Presented to the Faculty Department of Engineering Physics Graduate School of Engineering...SECOND-STAGE DIFFRACTIVE OPTICS Christopher M. Tulip Major, USAF Committee Membership: Lt Col Anthony L. Franz, PhD Chair

  5. Radiation engineering of optical antennas for maximum field enhancement.

    Science.gov (United States)

    Seok, Tae Joon; Jamshidi, Arash; Kim, Myungki; Dhuey, Scott; Lakhani, Amit; Choo, Hyuck; Schuck, Peter James; Cabrini, Stefano; Schwartzberg, Adam M; Bokor, Jeffrey; Yablonovitch, Eli; Wu, Ming C

    2011-07-13

    Optical antennas have generated much interest in recent years due to their ability to focus optical energy beyond the diffraction limit, benefiting a broad range of applications such as sensitive photodetection, magnetic storage, and surface-enhanced Raman spectroscopy. To achieve the maximum field enhancement for an optical antenna, parameters such as the antenna dimensions, loading conditions, and coupling efficiency have been previously studied. Here, we present a framework, based on coupled-mode theory, to achieve maximum field enhancement in optical antennas through optimization of optical antennas' radiation characteristics. We demonstrate that the optimum condition is achieved when the radiation quality factor (Q(rad)) of optical antennas is matched to their absorption quality factor (Q(abs)). We achieve this condition experimentally by fabricating the optical antennas on a dielectric (SiO(2)) coated ground plane (metal substrate) and controlling the antenna radiation through optimizing the dielectric thickness. The dielectric thickness at which the matching condition occurs is approximately half of the quarter-wavelength thickness, typically used to achieve constructive interference, and leads to ∼20% higher field enhancement relative to a quarter-wavelength thick dielectric layer.

  6. Large-scale optical diffraction tomography for inspection of optical plastic lenses

    CERN Document Server

    Kim, Kyoohyun; Park, YongKeun

    2015-01-01

    Herein is presented an optical diffraction tomography (ODT) technique for measuring 3-D refractive index (RI) maps of optical plastic lenses. A Mach-Zehnder interferometer was used to measure multiple complex optical fields of a plastic lens immersed in RI matching oil, at various rotational orientations. From this, ODT was used to reconstruct a 3-D RI distribution of the plastic lens with unprecedented RI sensitivity (dn = 4.21 x 10^-5) and high resolution (12.8 um). As a demonstration, 3-D RI distributions of a 2-mm-diameter borosilicate sphere and a 5-mm-diameter plastic lens

  7. Optical refractometry based on Fresnel diffraction from a phase wedge.

    Science.gov (United States)

    Tavassoly, M Taghi; Saber, Ahad

    2010-11-01

    A method that utilizes the Fresnel diffraction of light from the phase step formed by a transparent wedge is introduced for measuring the refractive indices of transparent solids, liquids, and solutions. It is shown that, as a transparent wedge of small apex angle is illuminated perpendicular to its surface by a monochromatic parallel beam of light, the Fresnel fringes, caused by abrupt change in refractive index at the wedge lateral boundary, are formed on a screen held perpendicular to the beam propagation direction. The visibility of the fringes varies periodically between zero and 1 in the direction normal to the wedge apex. For a known or measured apex angle, the wedge refractive index is obtained by measuring the period length by a CCD. To measure the refractive index of a transparent liquid or solution, the wedge is installed in a transparent rectangle cell containing the sample. Then, the cell is illuminated perpendicularly and the visibility period is measured. By using modest optics, one can measure the refractive index at a relative uncertainty level of 10(-5). There is no limitation on the refractive index range. The method can be applied easily with no mechanical manipulation. The measuring apparatus can be very compact with low mechanical and optical noises.

  8. Precision glass molding of high-resolution diffractive optical elements

    Science.gov (United States)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans P.; Plöger, Sven; Hermerschmidt, Andreas

    2016-04-01

    The demand of high resolution diffractive optical elements (DOE) is growing. Smaller critical dimensions allow higher deflection angles and can fulfill more demanding requirements, which can only be met by using electron-beam lithography. Replication techniques are more economical, since the high cost of the master can be distributed among a larger number of replicas. The lack of a suitable mold material for precision glass molding has so far prevented an industrial use. Glassy Carbon (GC) offers a high mechanical strength and high thermal strength. No anti-adhesion coatings are required in molding processes. This is clearly an advantage for high resolution, high aspect ratio microstructures, where a coating with a thickness between 10 nm and 200 nm would cause a noticeable rounding of the features. Electron-beam lithography was used to fabricate GC molds with highest precision and feature sizes from 250 nm to 2 μm. The master stamps were used for precision glass molding of a low Tg glass L-BAL42 from OHARA. The profile of the replicated glass is compared to the mold with the help of SEM images. This allows discussion of the max. aspect-ratio and min. feature size. To characterize optical performances, beamsplitting elements are fabricated and their characteristics were investigated, which are in excellent agreement to theory.

  9. 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.

  10. 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

  11. About Modeling the Excitation Conditions of Cherenkov and Diffraction Radiations in Periodic Metal-dielectric Structures

    Directory of Open Access Journals (Sweden)

    G.S. Vorobjov

    2015-06-01

    Full Text Available General procedure for modeling the excitation conditions of Cherenkov and diffraction radiations in periodic metal-dielectric structures is described. It is based on the representation of the electron beam space-charge wave in the form of a dielectric waveguide surface-wave. On the experimental facility of millimeter-wave the basic modes of excitation conditions of spatial harmonics of the Cherenkov and diffraction radiations are simulated. The method is tested by comparing the numerical analysis and experimental results on the layout of the device of the orotron type - generator of diffraction radiation.

  12. The Possibility of Noninvasive Micron High Energy Electron Beam Size Measurement Using Diffraction Radiation

    CERN Document Server

    Naumenko, Gennady; Aryshev, Alexander; Cline, David B; Fukui, Yasuo; Hamatsu, Ryosuke; Hayano, Hitoshi; Karataev, Pavel; Muto, Toshiya; Potylitsyn, Alexander; Ross, Marc; Urakawa, Junji

    2005-01-01

    During the last years a noninvasive method for beam size measurement based on the optical diffraction radiation (ODR) has been in progress (P. Karataev, et al., Physical Review Letters 93, 244802 (2004). However this technique encounters with hard sensitivity limitation for electron energies larger than several GeV. For example, for SLAC conditions the sensitivity of this method is 4 orders smaller than an appropriate one. We suggest to use a "dis-phased" slit target, where two semi-planes are turned with respect to each other at a small "dis-phased" angle. In order to ensure the interference between the diverged radiation beams we use a cylindrical lens. This method has much better sensitivity and resolution. A "dis-phased" angle 10 milliradians gives the optimal sensitivity to 5 microns transversal beam size. The theoretical model for calculating the ODR radiation from such targets (including focusing by cylindrical lens) is presented. It is shown that the sensitivity of this method does not depend on the L...

  13. Optical phased array radiating optical vortex with manipulated topological charges.

    Science.gov (United States)

    Ma, Xiaoliang; Pu, Mingbo; Li, Xiong; Huang, Cheng; Pan, Wenbo; Zhao, Bo; Cui, Jianhua; Luo, Xiangang

    2015-02-23

    Optical antennas are key elements in quantum optics emitting and sensing, and behave wide range applications in optical domain. However, integration of optical antenna radiating orbital angular momentum is still a challenge in nano-scale. We theoretically demonstrate a sub-wavelength phased optical antenna array, which manipulates the distribution of the orbital angular momentum in the near field. Orbital angular momentum with topological charge of 4 can be obtained by controlling the phase distribution of the fundamental mode orbital angular momentum in each antenna element. Our results indicate this phased array may be utilized in high integrated optical communication systems.

  14. Quantum vacuum radiation in optical glass

    CERN Document Server

    Liberati, Stefano; Visser, Matt

    2011-01-01

    A recent experimental claim of the detection of analogue Hawking radiation in an optical system [PRL 105 (2010) 203901] has led to some controversy [PRL 107 (2011) 149401, 149402]. While this experiment strongly suggests some form of particle creation from the quantum vacuum (and hence it is per se very interesting), it is also true that it seems difficult to completely explain all features of the observations by adopting the perspective of a Hawking-like mechanism for the radiation. For instance, the observed photons are emitted parallel to the optical horizon, and the relevant optical horizon is itself defined in an unusual manner by combining group and phase velocities. This raises the question: Is this really Hawking radiation, or some other form of quantum vacuum radiation? Naive estimates of the amount of quantum vacuum radiation generated due to the rapidly changing refractive index --- sometimes called the dynamical Casimir effect --- are not encouraging. However we feel that naive estimates could be ...

  15. Numerical simulation of optical vortex propagation and reflection by the methods of scalar diffraction theory

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, Nikolay V; Pavlov, Pavel V; Malov, A N

    2013-06-30

    Using the equations of scalar diffraction theory we consider the formation of an optical vortex on a diffractive optical element. The algorithms are proposed for simulating the processes of propagation of spiral wavefronts in free space and their reflections from surfaces with different roughness parameters. The given approach is illustrated by the results of numerical simulations. (propagation of wave fronts)

  16. Bragg diffraction from sub-micron particles isolated by optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yuan, E-mail: ygao0709@anl.gov; Harder, Ross; Southworth, Stephen; Guest, Jeffrey; Ocola, Leonidas; Young, Linda [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Scherer, Norbert; Yan, Zijie [Department of Chemistry, University of Chicago, Chicago, IL 60637 (United States); Pelton, Matthew [Department of Physics, University of Maryland, Baltimore County, MD 21250 (United States)

    2016-07-27

    We describe an apparatus using dynamic holographic optical tweezers which is capable of trapping and aligning a single micron scale anisotropic ZnO particle for x-ray Bragg diffraction experiments. The optical tweezers demonstrate enough stability to perform coherent x-ray diffraction imaging.

  17. 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...... of systematic tests, the applicability of this system is tested on an industrial 1 kW Nd:YAG laser. Three separate series of tests are conducted, one with the diffractive optical system at 500 W and two without the diffractive system at 400 W and 500 W, respectively. In principle the diffractive, optical system...

  18. Diffraction-based optical sensor detection system for capture-restricted environments

    Science.gov (United States)

    Khandekar, Rahul M.; Nikulin, Vladimir V.

    2008-04-01

    The use of digital cameras and camcorders in prohibited areas presents a growing problem. Piracy in the movie theaters results in huge revenue loss to the motion picture industry every year, but still image and video capture may present even a bigger threat if performed in high-security locations. While several attempts are being made to address this issue, an effective solution is yet to be found. We propose to approach this problem using a very commonly observed optical phenomenon. Cameras and camcorders use CCD and CMOS sensors, which include a number of photosensitive elements/pixels arranged in a certain fashion. Those are photosites in CCD sensors and semiconductor elements in CMOS sensors. They are known to reflect a small fraction of incident light, but could also act as a diffraction grating, resulting in the optical response that could be utilized to identify the presence of such a sensor. A laser-based detection system is proposed that accounts for the elements in the optical train of the camera, as well as the eye-safety of the people who could be exposed to optical beam radiation. This paper presents preliminary experimental data, as well as the proof-of-concept simulation results.

  19. Analysis of offset error for segmented micro-structure optical element based on optical diffraction theory

    Science.gov (United States)

    Su, Jinyan; Wu, Shibin; Yang, Wei; Wang, Lihua

    2016-10-01

    Micro-structure optical elements are gradually applied in modern optical system due to their characters such as light weight, replicating easily, high diffraction efficiency and many design variables. Fresnel lens is a typical micro-structure optical element. So in this paper we take Fresnel lens as base of research. Analytic solution to the Point Spread Function (PSF) of the segmented Fresnel lens is derived based on the theory of optical diffraction, and the mathematical simulation model is established. Then we take segmented Fresnel lens with 5 pieces of sub-mirror as an example. In order to analyze the influence of different offset errors on the system's far-field image quality, we obtain the analytic solution to PSF of the system under the condition of different offset errors by using Fourier-transform. The result shows the translation error along XYZ axis and tilt error around XY axis will introduce phase errors which affect the imaging quality of system. The translation errors along XYZ axis constitute linear relationship with corresponding phase errors and the tilt errors around XY axis constitute trigonometric function relationship with corresponding phase errors. In addition, the standard deviations of translation errors along XY axis constitute quadratic nonlinear relationship with system's Strehl ratio. Finally, the tolerances of different offset errors are obtained according to Strehl Criteria.

  20. Optical devices combining an organic semiconductor crystal with a two-dimensional inorganic diffraction grating

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, Takenori; Yamao, Takeshi, E-mail: yamao@kit.ac.jp; Hotta, Shu [Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)

    2016-02-01

    We have fabricated optical devices using an organic semiconductor crystal as an emission layer in combination with a two-dimensional (2D) inorganic diffraction grating used as an optical cavity. We formed the inorganic diffraction grating by wet etching of aluminum-doped zinc oxide (AZO) under a 2D cyclic olefin copolymer (COC) diffraction grating used as a mask. The COC diffraction grating was fabricated by nanoimprint lithography. The AZO diffraction grating was composed of convex prominences arranged in a triangular lattice. The organic crystal placed on the AZO diffraction grating indicated narrowed peaks in its emission spectrum under ultraviolet light excitation. These are detected parallel to the crystal plane. The peaks were shifted by rotating the optical devices around the normal to the crystal plane, which reflected the rotational symmetries of the triangular lattice through 60°.

  1. Optical schemes for speckle suppression by Barker code diffractive optical elements.

    Science.gov (United States)

    Lapchuk, A; Kryuchyn, A; Petrov, V; Shyhovets, O V; Pashkevich, G A; Bogdan, O V; Kononov, A; Klymenko, A

    2013-09-01

    A method for speckle suppression based on Barker code and M-sequence code diffractive optical elements (DOEs) is analyzed. An analytical formula for the dependence of speckle contrast on the wavelength of the laser illumination is derived. It is shown that speckle contrast has a wide maximum around the optimal wavelength that makes it possible to obtain large speckle suppression by using only one DOE for red, green, and blue laser illumination. Optical schemes for implementing this method are analyzed. It is shown that the method can use a simple liquid-crystal panel for phase rotation instead of a moving DOE; however, this approach requires a high frequency of liquid-crystal switching. A simple optical scheme is proposed using a 1D Barker code DOE and a simple 1D liquid-crystal panel, which does not require a high frequency of liquid-crystal switching or high-accuracy DOE movement.

  2. Diffractive Interface Theory: Nonlocal polarizability approach to the optics of metasurfaces

    CERN Document Server

    Roberts, Christopher M; Podolskiy, Viktor A

    2014-01-01

    We present a formalism for understanding the elecromagnetism of metasurfaces, optically thin composite films with engineered diffraction. The technique, diffractive interface theory (DIT), takes explicit advantage of the small optical thickness of a metasurface, eliminating the need for solving for light propagation inside the film and providing a direct link between the spatial profile of a metasurface and its diffractive properties. Predictions of DIT are compared with full-wave numerical solutions of Maxwell's equations, demonstrating DIT's validity and computational advantages for optically thin structures. Applications of the DIT range from understanding of fundamentals of light-matter interaction in metasurfaces to efficient analysis of generalized refraction to metasurface optimization.

  3. Diffractive interface theory: nonlocal susceptibility approach to the optics of metasurfaces.

    Science.gov (United States)

    Roberts, Christopher M; Inampudi, Sandeep; Podolskiy, Viktor A

    2015-02-09

    We present a formalism for understanding the electromagnetism of metasurfaces, optically thin composite films with engineered diffraction. The technique, diffractive interface theory (DIT), takes explicit advantage of the small optical thickness of a metasurface, eliminating the need for solving for light propagation inside the film and providing a direct link between the spatial profile of a metasurface and its diffractive properties. Predictions of DIT are compared with full-wave numerical solutions of Maxwell's equations, demonstrating DIT's validity and computational advantages for optically thin structures. Applications of the DIT range from understanding of fundamentals of light-matter interaction in metasurfaces to efficient analysis of generalized refraction to metasurface optimization.

  4. A single diffractive optical element implementing spectrum-splitting and beam-concentration functions simultaneously with high diffraction efficiency

    Institute of Scientific and Technical Information of China (English)

    Ye Jia-Sheng; Wang Jin-Ze; Huang Qing-Li; Dong Bi-Zhen; Zhang Yan; Yang Guo-Zhen

    2013-01-01

    In this paper,a novel method is proposed and employed to design a single diffractive optical element (DOE) for implementing spectrum-splitting and beam-concentration (SSBC) functions simultaneously.We develop an optimization algorithm,through which the SSBC DOE can be optimized within an arbitrary thickness range according to the limitations of modem photolithography technology.Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency.It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems.

  5. A single diffractive optical element for implementing spectrum-splitting and beam-concentration functions simultaneously with high diffraction efficiency

    CERN Document Server

    Ye, Jia-Sheng; Huang, Qing-Li; Dong, Bi-Zhen; Zhang, Yan; Yang, Guo-Zhen

    2013-01-01

    In this paper, a novel method is proposed, and employed to design a single diffractive optical element (DOE) for implementing spectrum-splitting and beam-concentration (SSBC) functions simultaneously. We develop an optimization algorithm, through which the SSBC DOE can be optimized within an arbitrary thickness range, according to the limitations of modern photolithography technology. Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency. It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems.

  6. Research on the Design of an Optical Information Storage Sensing System Using a Diffractive Optical Element

    Directory of Open Access Journals (Sweden)

    Min Gu

    2013-11-01

    Full Text Available This paper introduces a compact optical information storage sensing system. Applications of this system include longitudinal surface plasmon resonance detection of gold nanorods with a single femtosecond laser in three-dimensional space as well as data storage. A diffractive optical element (DOE is applied in the system to separate the recording-reading beam from the servo beam. This allows us to apply a single laser and one objective lens in a single optical path for the servo beam and the recording-reading beam. The optical system has a linear region of 8 λ, which is compatible with current DVD servo modules. The wavefront error of the optical system is below 0.03 λrms. The minimum grating period of the DOE is 13.4 µm, and the depth of the DOE is 1.2 µm, which makes fabrication of it possible. The DOE is also designed to conveniently control the layer-selection process, as there is a linear correlation between the displacement of the DOE and the layer-selection distance. The displacement of DOE is in the range of 0–6.045 mm when the thickness of the layer-selection is 0.3 mm. Experiments were performed and the results have been verified.

  7. Simulation study of transverse optical klystron radiation

    Institute of Scientific and Technical Information of China (English)

    XuHong-Liang; DiaoCao-Zheng; 等

    1997-01-01

    The radiation from a transverse optical klystron(TOK) is calculated by far field approximation 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.

  8. Multifrequency Magneto-optic Bragg Diffraction and Radio Frequency Signal Parallel Processing

    Institute of Scientific and Technical Information of China (English)

    SHANG Dan; WU Bao-jian; QIU Kun

    2008-01-01

    Magneto-optic(MO) coupling of guided optical waves with microwave magnetostatic waves(MSWs) simultaneously excited by multiple radio frequency(RF) signals can lead to multifrequency diffraction effects and then parallel processing of RF signals can be realized by using of the characteristics that diffraction efficiencies(Des) are approximately in direct proportion to RF signals intensities and diffraction angles are related to frequencies of the corresponding RF signals within linear MO interaction region. In this paper, studied is the multifrequency MO Bragg diffraction in first-order MO interaction approximation, and obtained was the approximate analytical expression for principle diffraction efficiency(PDE). Also, put forward was a parallel imaging method of relative intensity of RF signals based on single-frequency diffraction. By calculation and analysis, it is shown that the relative error is not more than 0.3 dB for the case of three RF signals within the frequency space of 60 MHz.

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

    Science.gov (United States)

    Alexeyev, V. I.; Eliseyev, A. N.; Irribarra, E.; Kishin, I. A.; Kubankin, A. S.; Nazhmudinov, R. M.

    2016-08-01

    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.

  10. Ionizing radiation detector using multimode optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Suter, J.J. (Johns Hopkins Univ., Laurel, MD (United States). Applied Physics Lab.); Poret, J.C.; Rosen, M. (Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering); Rifkind, J.M. (National Inst. of Health, Baltimore, MD (United States). Lab. of Cellular and Molecular Biology)

    1993-08-01

    An optical ionizing radiation detector, based on the attenuation of 850-nm light in 50/125-[mu]m 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-[mu]m 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.

  11. Optical Radiation Bioeffects TO9

    Science.gov (United States)

    2009-02-01

    Absorption coefficient data from a spectrophotometry study. ............................ 23 Figure 15 Combined data from Figures 13 and 14, showing...distribution unlimited Figure 14 Absorption coefficient data from a spectrophotometry study. The results of Figure 13, and the...G. Y. Swanland, R. J. Thomas, and A. T. Tsin, 2006, Optical properties of ocular tissues in the near infrared region, Ophthalmic Technologies XVI

  12. Optical color-image encryption and synthesis using coherent diffractive imaging in the Fresnel domain.

    Science.gov (United States)

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

    2012-02-13

    We propose a new method using coherent diffractive imaging for optical color-image encryption and synthesis in the Fresnel domain. An optical multiple-random-phase-mask encryption system is applied, and a strategy based on lateral translations of a phase-only mask is employed during image encryption. For the decryption, an iterative phase retrieval algorithm is applied to extract high-quality decrypted color images from diffraction intensity maps (i.e., ciphertexts). In addition, optical color-image synthesis is also investigated based on coherent diffractive imaging. Numerical results are presented to demonstrate feasibility and effectiveness of the proposed method. Compared with conventional interference methods, coherent diffractive imaging approach may open up a new research perspective or can provide an effective alternative for optical color-image encryption and synthesis.

  13. Microlithography application for production of multilevel diffractive optical elements (as a security hologram feature)

    Science.gov (United States)

    Braginets, Eugene; Kurashov, V.; Honcharuk, S.; Girnyk, V.; Kostyukevych, S.; Kostyukevych, K.

    2011-02-01

    The goal of a present research is to develop a method for production of multilevel Diffractive Optical Elements (DOEs) for use in Digital Security Holograms, using the direct-writing maskless lithography system.

  14. Radiating subdispersive fractional optical solitons

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, J., E-mail: fujioka@fisica.unam.mx; Espinosa, A.; Rodríguez, R. F. [Departamento de Física Química, Instituto de Física, Universidad Nacional Autónoma de México, Mexico, DF 04510 (Mexico); Malomed, B. A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-09-01

    It was recently found [Fujioka et al., Phys. Lett. A 374, 1126 (2010)] that the propagation of solitary waves can be described by a fractional extension of the nonlinear Schrödinger (NLS) equation which involves a temporal fractional derivative (TFD) of order α > 2. In the present paper, we show that there is also another fractional extension of the NLS equation which contains a TFD with α < 2, and in this case, the new equation describes the propagation of radiating solitons. We show that the emission of the radiation (when α < 2) is explained by resonances at various frequencies between the pulses and the linear modes of the system. It is found that the new fractional NLS equation can be derived from a suitable Lagrangian density, and a fractional Noether's theorem can be applied to it, thus predicting the conservation of the Hamiltonian, momentum and energy.

  15. FABRICATION OF TRANSMISSIVE DIFFRACTIVE OPTICAL ELEMENTS FOR THE MID-INFRARED WITH A LASER WRITING INSTRUMENT

    Directory of Open Access Journals (Sweden)

    S. Calixto

    2007-08-01

    Full Text Available A simple method to fabricate infrared (λ = 10.6 μm diffractive optical elements that work in a transmissionmode is presented. A laser-writing instrument completely under computer control has been built todemonstrate the feasibility of this method. Several diffractive elements, fabricated using the laser-writinginstrument, are described.

  16. Diffractive optics for combined spatial- and mode- division demultiplexing of optical vortices: design, fabrication and optical characterization

    Science.gov (United States)

    Ruffato, Gianluca; Massari, Michele; Romanato, Filippo

    2016-04-01

    During the last decade, the orbital angular momentum (OAM) of light has attracted growing interest as a new degree of freedom for signal channel multiplexing in order to increase the information transmission capacity in today’s optical networks. Here we present the design, fabrication and characterization of phase-only diffractive optical elements (DOE) performing mode-division (de)multiplexing (MDM) and spatial-division (de)multiplexing (SDM) at the same time. Samples have been fabricated with high-resolution electron-beam lithography patterning a polymethylmethacrylate (PMMA) resist layer spun over a glass substrate. Different DOE designs are presented for the sorting of optical vortices differing in either OAM content or beam size in the optical regime, with different steering geometries in far-field. These novel DOE designs appear promising for telecom applications both in free-space and in multi-core fibers propagation.

  17. Tunable Diffractive Optical Elements Based on Shape-Memory Polymers Fabricated via Hot Embossing.

    Science.gov (United States)

    Schauer, Senta; Meier, Tobias; Reinhard, Maximilian; Röhrig, Michael; Schneider, Marc; Heilig, Markus; Kolew, Alexander; Worgull, Matthias; Hölscher, Hendrik

    2016-04-13

    We introduce actively tunable diffractive optical elements fabricated from shape-memory polymers (SMPs). By utilizing the shape-memory effect of the polymer, at least one crucial attribute of the diffractive optical element (DOE) is tunable and adjustable subsequent to the completed fabrication process. A thermoplastic, transparent, thermoresponsive polyurethane SMP was structured with diverse diffractive microstructures via hot embossing. The tunability was enabled by programming a second, temporary shape into the diffractive optical element by mechanical deformation, either by stretching or a second embossing cycle at low temperatures. Upon exposure to the stimulus heat, the structures change continuously and controllable in a predefined way. We establish the novel concept of shape-memory diffractive optical elements by illustrating their capabilities, with regard to tunability, by displaying the morphing diffractive pattern of a height tunable and a period tunable structure, respectively. A sample where an arbitrary structure is transformed to a second, disparate one is illustrated as well. To prove the applicability of our tunable shape-memory diffractive optical elements, we verified their long-term stability and demonstrated the precise adjustability with a detailed analysis of the recovery dynamics, in terms of temperature dependence and spatially resolved, time-dependent recovery.

  18. 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.

  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. Experimental Characterization of Sub-picosecond Electron Bunch Length with Coherent Diffraction Radiation

    Institute of Scientific and Technical Information of China (English)

    XIANG Dao; YANG Xing-Fan; HUANG Wen-Hui; TANG Chuan-Xiang; LIN Yu-Zheng; LI Wei-Hua; PAN Qing; LI Ming

    2008-01-01

    Diffraction radiation is one of the most promising candidates for electron beam diagnostics for the International Linear Collider, x-ray free electron lasers and energy recovery linac due to its non-intercepting characteristics. We report the non-intercepting measurement of sub-ps electron bunch length with coherent diffraction radiation. The bunch length is measured with a Martin-Puplett interferometer and the detailed longitudinal bunch shape is reconstructed with the Kramers-Kronig relation. The rms bunch length is found to be about 0.73ps, which confirms a successful commissioning of the bunch compressor and the interferometer.

  1. 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

    of systematic tests, the applicability of this system is tested on an industrial 1 kW Nd:YAG laser. Three separate series of tests are conducted, one with the diffractive optical system at 500 W and two without the diffractive system at 400 W and 500 W, respectively. In principle the diffractive, optical system......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...... functions as intended. Three spots are produced with a variable amount of energy between the center spot and two support spots. On average, the penetration depth drops to roughly half of that obtained with standard optics and the seam width increases 30 to 40 percent. The results show that at similar...

  2. 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.

  3. 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)

  4. 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...... optimization of the input aperture parameters according to desired output characteristics. For wavefront sensing, the achieved aperture control opens a new degree of freedom for improving the accuracy of quantitative phase imaging. Diffractive GPC input modulation also fits well with grating-based optical...

  5. Design and optimization of broadband wide-angle antireflection structures for binary diffractive optics.

    Science.gov (United States)

    Chang, Chih-Hao; Waller, Laura; Barbastathis, George

    2010-04-01

    We propose a class of antireflecting structures that can effectively suppress reflections for binary diffractive optics. In this structure, multiple periodic thin films with gradually varying refractive indices are used to shift all reflected diffraction to the transmitted orders. The structure is optimized to operate over broad bands and wide angles using rigorous coupled-wave analysis and genetic algorithms. We validated the structure numerically using finite-difference time-domain methods. The proposed structure may lead to more efficient diffractive devices for applications in thin-film photovoltaic, waveguide coupler, and holographic optical elements.

  6. Optical Absorption and X—Ray DIffractionStudies of Sulfur Under High Pressure

    Institute of Scientific and Technical Information of China (English)

    陈良辰; 王莉君

    1999-01-01

    In situ high pressure optical absorption measurements of sulfur have been carried out by using DAC device with a TASCO V-550 UV-VIS spectrophotometer at pressures up to 41.6GPa.The curves of absorption edge vs pressure were obtained.in which there are two turning points at about 5 and 12GPa,corresponding to two changes of colour in the optical observation:one is from yellow to red and the other from red to black at 5-6\\5and 10-12GPa,respectively.The absorption edge reaches above 800nm when the pressure is increased to 23GPa.The sturcture and phase transitions have also been investigated by using in situ high pressure energy-dispersive x-ray diffraction with synchrotron radiation at pressures up to 33.7GPa.No structure phase transition occurs at 5-6GPa.but there is a new high-pressure phase,caused probably by the reorientation or ordering of S8.

  7. 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.

  8. Simulation of Coherent Diffraction Radiation Generation by Pico-Second Electron Bunches in an Open Resonator

    Science.gov (United States)

    Sukhikh, L. G.; Potylitsyn, A. P.; Verigin, D. A.

    2016-07-01

    In this report we present new approach for calculation of processes of diffraction radiation generation, storage and decay in an open resonator based on generalized surface current method. The radiation characteristics calculated using the developed approach were compared with those calculated using Gaussian-Laguerre modes method. The comparison shows reasonable coincidence of the results that allows to use developed method for investigation of more complicated resonators.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kassemeyer, Stephan

    2014-05-20

    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

  10. Diffractive optical elements and quasioptical schemes for experiments on a high-power terahertz free-electron laser

    Science.gov (United States)

    Vinokurov, N. A.; Zhigach, S. A.; Knyazev, B. A.; Konysheva, A. V.; Kulipanov, G. N.; Merzhievsky, L. A.; Polskikh, I. A.; Cherkassky, V. S.

    2007-10-01

    We have developed reflective diffraction optical elements (DOE) for focusing monochromatic coherent radiation of 400 W terahertz Novosibirsk free-electron laser (FEL). Operational characteristics of two modifications of the refractive kinoform lenses were studied. Quasioptical Toepler system with terahertz radiation recording by a thermosensitive luminescent screen was fabricated for the examination of film and solid deformation. A system for real-time terahertz radioscopy of objects with image recording with a microbolometer matrix (MBM) was fabricated. Images of objects illuminated with a plane wave or diffuse radiation were studied with the MBM. It was shown that the speckle pattern, which appears in the second case, can be averaged by means of the scatterer rotation.

  11. Fabrication of Diffractive Optical Elements for an Integrated Compact Optical-MEMS Laser Scanner

    Energy Technology Data Exchange (ETDEWEB)

    WENDT,JOEL R.; KRYGOWSKI,T.W.; VAWTER,GREGORY A.; SPAHN,OLGA B.; SWEATT,WILLIAM C.; WARREN,MIAL E.; REYES,DAVID NMN

    2000-07-13

    The authors describe the microfabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear. Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is {+-}4{degree} with a spot size of 0.5 mm.

  12. Coupling light into optical fibres near the diffraction limit

    CERN Document Server

    Horton, A J; Horton, Anthony J.; Bland-Hawthorn, Joss

    2006-01-01

    The burgeoning field of astrophotonics explores the interface between astronomy and photonics. Important applications include photonic OH suppression at near-infrared wavelengths, and integrated photonic spectroscopy. These new photonic mechanisms are not well matched to conventional multi-mode fibres and are best fed with single or few-mode fibres. We envisage the largest gains in astrophotonics will come from instruments that operate with single or few-mode fibres in the diffraction limited or near diffraction limited regimes. While astronomical instruments have largely solved the problem of coupling light into multi-mode fibres this is largely unexplored territory for few-mode and single-mode fibres. Here we describe a project to explore this topic in detail, and present initial results on coupling light into single and few-mode fibres at the diffraction limit. We find that fibres with as few as ~5 guided modes have qualitatively different behaviour to single-mode fibres and share a number of the beneficia...

  13. Thermal Weapon Sight (TWS) AN/PAS-13 diffractive optics designed for producibility

    Science.gov (United States)

    Anderson, J. Steven; Chen, Chungte W.; Spande, Robert A.

    1993-01-01

    The Thermal Weapon Sight (TWS) program is a manportable 3-5 micrometer forward-looking-infrared (FLIR) rifle sight. The manportable nature requires that the optics modules be lightweight, low cost and compact while maximizing performance. These objectives were met with diffractive optics. TWS promises to be the first FLIR sensor to incorporate kinoform surfaces in full scale production.

  14. Body-centered cubic dissipative crystal formation in a dispersive and diffractive optical parametric oscillator.

    Science.gov (United States)

    Tlidi, M; Pieroux, D; Mandel, Paul

    2003-09-15

    We show that coupling diffraction and chromatic dispersion lead to body-centered cubic and hexagonally packed cylinders of dissipative optical crystals in a degenerate optical parametric oscillator. The stabilization of these crystals is a direct consequence of the interaction between the modulational and the quasi-neutral modes.

  15. Advanced optic fabrication using ultrafast laser radiation

    Science.gov (United States)

    Taylor, Lauren L.; Qiao, Jun; Qiao, Jie

    2016-03-01

    Advanced fabrication and finishing techniques are desired for freeform optics and integrated photonics. Methods including grinding, polishing and magnetorheological finishing used for final figuring and polishing of such optics are time consuming, expensive, and may be unsuitable for complex surface features while common photonics fabrication techniques often limit devices to planar geometries. Laser processing has been investigated as an alternative method for optic forming, surface polishing, structure writing, and welding, as direct tuning of laser parameters and flexible beam delivery are advantageous for complex freeform or photonics elements and material-specific processing. Continuous wave and pulsed laser radiation down to the nanosecond regime have been implemented to achieve nanoscale surface finishes through localized material melting, but the temporal extent of the laser-material interaction often results in the formation of a sub-surface heat affected zone. The temporal brevity of ultrafast laser radiation can allow for the direct vaporization of rough surface asperities with minimal melting, offering the potential for smooth, final surface quality with negligible heat affected material. High intensities achieved in focused ultrafast laser radiation can easily induce phase changes in the bulk of materials for processing applications. We have experimentally tested the effectiveness of ultrafast laser radiation as an alternative laser source for surface processing of monocrystalline silicon. Simulation of material heating associated with ultrafast laser-material interaction has been performed and used to investigate optimized processing parameters including repetition rate. The parameter optimization process and results of experimental processing will be presented.

  16. A Furnace for Diffraction Studies using Synchrotron X-Ray Radiation

    DEFF Research Database (Denmark)

    Buras, B.; Lebech, Bente; Kofoed, W.

    1984-01-01

    A furnace for diffraction studies using synchrotron X-ray radiation is described. The furnace can be operated between ambient temperature and 1 800 °C with a temperature stability better than 5 °C for temperatures above 300 °C. Kapton windows allow almost 360° access for the X-ray beam in the hor...

  17. Diffraction radiation from an inhomogeneous dielectric film on the surface of a perfect conductor

    NARCIS (Netherlands)

    Ryazanov, MI; Strikhanov, MN; Tishchenko, AA

    2004-01-01

    Diffraction radiation generated by a charged particle moving uniformly parallel to the surface of a perfect conductor coated with a dielectric film is considered; the thickness of the film is an arbitrary function of coordinates. A particular case is considered when this function is periodic in one

  18. Damage investigation on tungsten and diamond diffractive optics at a hard x-ray free-electron laser.

    Science.gov (United States)

    Uhlén, Fredrik; Nilsson, Daniel; Holmberg, Anders; Hertz, Hans M; Schroer, Christian G; Seiboth, Frank; Patommel, Jens; Meier, Vivienne; Hoppe, Robert; Schropp, Andreas; Lee, Hae Ja; Nagler, Bob; Galtier, Eric; Krzywinski, Jacek; Sinn, Harald; Vogt, Ulrich

    2013-04-08

    Focusing hard x-ray free-electron laser radiation with extremely high fluence sets stringent demands on the x-ray optics. Any material placed in an intense x-ray beam is at risk of being damaged. Therefore, it is crucial to find the damage thresholds for focusing optics. In this paper we report experimental results of exposing tungsten and diamond diffractive optics to a prefocused 8.2 keV free-electron laser beam in order to find damage threshold fluence levels. Tungsten nanostructures were damaged at fluence levels above 500 mJ/cm(2). The damage was of mechanical character, caused by thermal stress variations. Diamond nanostructures were affected at a fluence of 59 000 mJ/cm(2). For fluence levels above this, a significant graphitization process was initiated. Scanning Electron Microscopy (SEM) and µ-Raman analysis were used to analyze exposed nanostructures.

  19. 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.

  20. 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.

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

    Science.gov (United States)

    Chen, Wen; Chen, Xudong

    2011-05-01

    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.

  2. Experimental Research of the Diffraction and Vavilov-Cherenkov Radiation Generation in a Teflon Target

    CERN Document Server

    Shevelev, M; Potylitsyn, A; Popov, Yu

    2011-01-01

    Geometry of Vavilov-Cherekov (VChR) radiation when an electron moves close to a dielectric target is in analogy to diffraction radiation (DR) geometry. In this case we may expect DR generation from the upstream face of the target besides that VChR. The joint observation of these booth types of radiation is very interesting from the pseudo-photon viewpoint, which is applicable for relativistic electrons. Unexpected results obtained in our experiment insist on reflection about nature both DR and VChR. The experiment was performed on the relativistic electron beam of the microtron of Tomsk Polytechnic University.

  3. Corrective optics for diffraction of {gamma}-rays

    Energy Technology Data Exchange (ETDEWEB)

    Materna, T. [Nuclear Physics Institute, University of Cologne, Zuelpicher Str. 77, D-50937 Cologne (Germany) and Institut Laue-Langevin, F-38042 Grenoble, Cedex 9 (France)]. E-mail: materna@ill.fr; Bruyneel, B. [Nuclear Physics Institute, University of Cologne, Zuelpicher Str. 77, D-50937 Cologne (Germany); Jolie, J. [Nuclear Physics Institute, University of Cologne, Zuelpicher Str. 77, D-50937 Cologne (Germany); Linnemann, A. [Nuclear Physics Institute, University of Cologne, Zuelpicher Str. 77, D-50937 Cologne (Germany); Warr, N. [Nuclear Physics Institute, University of Cologne, Zuelpicher Str. 77, D-50937 Cologne (Germany); Boerner, H.G. [Institut Laue-Langevin, F-38042 Grenoble, Cedex 9 (France); Jentschel, M. [Institut Laue-Langevin, F-38042 Grenoble, Cedex 9 (France); Mutti, P. [Institut Laue-Langevin, F-38042 Grenoble, Cedex 9 (France); Simpson, G. [Institut Laue-Langevin, F-38042 Grenoble, Cedex 9 (France)

    2006-12-21

    A new method to correct imperfect bending of curved crystals used for {gamma}-ray diffraction spectroscopy is presented. It relies on using position-sensitive segmented Ge-detectors and permits the determination of the emission area of each {gamma}-ray from the crystals and therefore an off-line correction of bending imperfections as if the crystals were divided into independent 2x2 mm{sup 2} bent crystals. A first experiment using the GAMS-5 spectrometer (Institut Laue-Langevin) shows proof of the principle of the method.

  4. Chromatic error correction of diffractive optical elements at minimum etch depths

    Science.gov (United States)

    Barth, Jochen; Gühne, Tobias

    2014-09-01

    The integration of diffractive optical elements (DOE) into an optical design opens up new possibilities for applications in sensing and illumination. If the resulting optics is used in a larger spectral range we must correct not only the chromatic error of the conventional, refractive, part of the design but also of the DOE. We present a simple but effective strategy to select substrates which allow the minimum etch depths for the DOEs. The selection depends on both the refractive index and the dispersion.

  5. Synchrotron radiation X-ray powder diffraction techniques applied in hydrogen storage materials - A review

    Directory of Open Access Journals (Sweden)

    Honghui Cheng

    2017-02-01

    Full Text Available Synchrotron radiation is an advanced collimated light source with high intensity. It has particular advantages in structural characterization of materials on the atomic or molecular scale. Synchrotron radiation X-ray powder diffraction (SR-XRPD has been successfully exploited to various areas of hydrogen storage materials. In the paper, we will give a brief introduction on hydrogen storage materials, X-ray powder diffraction (XRPD, and synchrotron radiation light source. The applications of ex situ and in situ time-resolved SR-XRPD in hydrogen storage materials, are reviewed in detail. Future trends and proposals in the applications of the advanced XRPD techniques in hydrogen storage materials are also discussed.

  6. Acousto-optic modulation and deflection of terahertz electromagnetic radiation in nonpolar liquids

    Science.gov (United States)

    Nikitin, P. A.; Voloshinov, V. B.; Gerasimov, V. V.; Knyazev, B. A.

    2017-07-01

    The results of a series of experiments on controlled deflection of electromagnetic radiation of a free-electron laser upon diffraction by an acoustic wave in nonpolar liquids are presented. Acoustic and optical properties of liquids that are transparent in the terahertz range are discussed. It is demonstrated that nonpolar liquids may turn out to be a more efficient acousto-optic interaction medium than dielectric crystals or semiconductors.

  7. Diffraction microgratings as a novel optical biosensing platform

    Science.gov (United States)

    Baikova, Tatiana V.; Danilov, Pavel A.; Gonchukov, Sergey A.; Yermachenko, Valery M.; Ionin, Andrey A.; Khmelnitskii, Roman A.; Kudryashov, Sergey I.; Nguyen, Trang T. H.; Rudenko, Andrey A.; Saraeva, Irina N.; Svistunova, Tatiana S.; Zayarny, Dmitry A.

    2016-07-01

    Using a micro-hole grating in a supported silver film as a laser-fabricated novel optical platform for surface-enhanced IR absoprtion/reflection spectroscopy, characteristic absorption bands of Staphylococcus aureus, in particular, its buried carotenoid fragments, were detected in FT-IR spectra with 10-fold analytical enhancement, paving the way for the spectral express-identification of pathogenic microorganisms.

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

    CERN Document Server

    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.

  9. Extremely asymmetric diffraction as a method of determining magneto-optical constants for X-rays near absorption edges

    Energy Technology Data Exchange (ETDEWEB)

    Andreeva, M. A., E-mail: Mandreeva1@yandex.ru [Moscow State University (Russian Federation); Repchenko, Yu. L., E-mail: kent160@mail.ru [Voronezh State University (Russian Federation); Smekhova, A. G. [Moscow State University (Russian Federation); Dumesnil, K. [University of Lorraine, Institut Jean Lamour (UMR CNRS 7198) (France); Wilhelm, F.; Rogalev, A. [European Synchrotron Radiation Facility (France)

    2015-06-15

    The spectral dependence of the Bragg peak position under conditions of extremely asymmetric diffraction has been analyzed in the kinematical and dynamical approximations of the diffraction theory. Simulations have been performed for the L{sub 3} absorption edge of yttrium in a single-crystal YFe{sub 2} film; they have shown that the magneto-optical constants (or, equivalently, the dispersion corrections to the atomic scattering factor) for hard X-rays can be determined from this dependence. Comparison with the experimental data obtained for a Nb(4 nm)/YFe{sub 2}(40 nm〈110〉)/Fe(1.5 nm)/Nb(50 nm)/sapphire sample at the European Synchrotron Radiation Facility has been made.

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

    DEFF Research Database (Denmark)

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

    1998-01-01

    of the different set-ups are described and potential applications are discussed. First experiments were performed, investigating with high spatial resolution the residual strain gradients in layered polycrystalline materials. The results underline that focused high-energy synchrotron radiation can provide unique...... information on the mesoscopic scale to the materials scientist, complementary to existing techniques based on conventional X-ray sources, neutron scattering or electron microscopy....

  11. An analysis of the radiation from apertures in curved surfaces by the geometrical theory of diffraction. [ray technique for electromagnetic fields

    Science.gov (United States)

    Pathak, P. H.; Kouyoumjian, R. G.

    1974-01-01

    In this paper the geometrical theory of diffraction is extended to treat the radiation from apertures of slots in convex perfectly conducting surfaces. It is assumed that the tangential electric field in the aperture is known so that an equivalent infinitesimal source can be defined at each point in the aperture. Surface rays emanate from this source which is a caustic of the ray system. A launching coefficient is introduced to describe the excitation of the surface ray modes. If the field radiated from the surface is desired, the ordinary diffraction coefficients are used to determine the field of the rays shed tangentially from the surface rays. The field of the surface ray modes is not the field on the surface; hence if the mutual coupling between slots is of interest, a second coefficient related to the launching coefficient must be employed. In the region adjacent to the shadow boundary, the component of the field directly radiated from the source is represented by Fock-type functions. In the illuminated region the incident radiation from the source (this does not include the diffracted field components) is treated by geometrical optics. This extension of the geometrical theory of diffraction is applied to calculate the radiation from slots on elliptic cylinders, spheres, and spheroids.

  12. Optically Induced Lattice Dynamics of hexagonal manganite using Ultrafast X-ray Diffraction

    Science.gov (United States)

    Lee, Hae Ja; Workman, J. B.; Hur, N.

    2005-03-01

    We have studied the picosecond lattice dynamics of optically pumped hexagonal manganite LuMnO3 using ultrafast x-ray diffraction. The results show a shift and broadening of the diffraction curve due to the stimulated lattice expansion. To understand the transient response of the lattice, the measured time- and angle-resolved diffraction curves are compared with a theoretical calculation based on dynamical diffraction theory modified for the hexagonal crystal structure of LuMnO3. Our simulations reveal that a large coupling coefficient between the a-b plane and the c-axis (c13) is required to the data. We compare this result to our previous coherent phonon studies of LuMnO3 using optical pump-probe spectroscopy.

  13. Design and verification of diffractive optical elements for speckle generation of 3-D range sensors

    Science.gov (United States)

    Du, Pei-Qin; Shih, Hsi-Fu; Chen, Jenq-Shyong; Wang, Yi-Shiang

    2016-09-01

    The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper.

  14. Design and verification of diffractive optical elements for speckle generation of 3-D range sensors

    Science.gov (United States)

    Du, Pei-Qin; Shih, Hsi-Fu; Chen, Jenq-Shyong; Wang, Yi-Shiang

    2016-12-01

    The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper.

  15. Nonlinear Optical Materials for the Smart Filtering of Optical Radiation.

    Science.gov (United States)

    Dini, Danilo; Calvete, Mário J F; Hanack, Michael

    2016-11-23

    The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the function of optical power limiting. All known mechanisms of optical limiting have been analyzed and discussed for the different types of materials.

  16. Optical theorem for multipole sources in wave diffraction theory

    Science.gov (United States)

    Eremin, Yu. A.; Sveshnikov, A. G.

    2016-05-01

    The optical theorem is generalized to the case of local body excitation by multipole sources. It is found that, to calculate the extinction cross section, it is sufficient to calculate the scattered field derivatives at a single point. It is shown that the Purcell factor, which is a rather important parameter, can be represented in analytic form. The result is generalized to the case of a local scatterer incorporated in a homogeneous halfspace.

  17. 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...... in future technologies. For this to come true, more advanced optical signal processing must be achieved in miniaturized multifunctional components which should enable optimal light control and light localization. These components have complex subwavelength geometries and material distributions......, 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...

  18. Challenges in mold manufacturing for high precision molded diffractive optical elements

    Science.gov (United States)

    Pongs, Guido; Bresseler, Bernd; Schweizer, Klaus; Bergs, Thomas

    2016-09-01

    Isothermal precision glass molding of imaging optics is the key technology for mass production of precise optical elements. Especially for numerous consumer applications (e.g. digital cameras, smart phones, …), high precision glass molding is applied for the manufacturing of aspherical lenses. The usage of diffractive optical elements (DOEs) can help to further reduce the number of lenses in the optical systems which will lead to a reduced weight of hand-held optical devices. But today the application of molded glass DOEs is limited due to the technological challenges in structuring the mold surfaces. Depending on the application submicrometer structures are required on the mold surface. Furthermore these structures have to be replicated very precisely to the glass lens surface. Especially the micro structuring of hard and brittle mold materials such as Tungsten Carbide is very difficult and not established. Thus a multitude of innovative approaches using diffractive optical elements cannot be realized. Aixtooling has investigated in different mold materials and different suitable machining technologies for the micro- and sub-micrometer structuring of mold surfaces. The focus of the work lays on ultra-precision grinding to generate the diffractive pattern on the mold surfaces. This paper presents the latest achievements in diffractive structuring of Tungsten Carbide mold surfaces by ultra-precision grinding.

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Milch, J R

    1978-10-18

    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/sup 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.

  1. Design of tracking and detecting lens system by diffractive optical method

    Science.gov (United States)

    Yang, Jiang; Qi, Bo; Ren, Ge; Zhou, Jianwei

    2016-10-01

    Many target-tracking applications require an optical system to acquire the target for tracking and identification. This paper describes a new detecting optical system that can provide automatic flying object detecting, tracking and measuring in visible band. The main feature of the detecting lens system is the combination of diffractive optics with traditional lens design by a technique was invented by Schupmann. Diffractive lens has great potential for developing the larger aperture and lightweight lens. First, the optical system scheme was described. Then the Schupmann achromatic principle with diffractive lens and corrective optics is introduced. According to the technical features and requirements of the optical imaging system for detecting and tracking, we designed a lens system with flat surface Fresnel lens and cancels the optical system chromatic aberration by another flat surface Fresnel lens with effective focal length of 1980mm, an F-Number of F/9.9 and a field of view of 2ωω = 14.2', spatial resolution of 46 lp/mm and a working wavelength range of 0.6 0.85um. At last, the system is compact and easy to fabricate and assembly, the diffuse spot size and MTF function and other analysis provide good performance.

  2. Novel optical super-resolution pattern with upright edges diffracted by a tiny thin aperture.

    Science.gov (United States)

    Wu, Jiu Hui; Zhou, Kejiang

    2015-08-24

    In the past decade numerous efforts have been concentrated to achieve optical imaging resolution beyond the diffraction limit. In this letter a thin microcavity theory of near-field optics is proposed by using the power flow theorem firstly. According to this theory, the near-field optical diffraction from a tiny aperture whose diameter is less than one-tenth incident wavelength embedded in a thin conducting film is investigated by considering this tiny aperture as a thin nanocavity. It is very surprising that there exists a kind of novel super-resolution diffraction patterns showing resolution better than λ/80 (λ is the incident wavelength), which is revealed for the first time to our knowledge in this letter. The mechanism that has allowed the imaging with this kind of super-resolution patterns is due to the interaction between the incident wave and the thin nanocavity with a complex wavenumber. More precisely, these super-resolution patterns with discontinuous upright peaks are formed by one or three items of the integration series about the cylindrical waves according to our simulation results. This novel optical super-resolution with upright edges by using the thin microcavity theory presented in the study could have potential applications in the future semiconductor lithography process, nano-size laser-drilling technology, microscopy, optical storage, optical switch, and optical information processing.

  3. Synchrotron Powder Diffraction Study of Radiation Damage in Langmuir Blodgett Nanotemplate Crystallised Protein

    Directory of Open Access Journals (Sweden)

    Jonathan P. Wright

    2014-01-01

    Full Text Available Polycrystalline samples of lysozyme were prepared with and without a Langmuir-Blodgett (LB thin film template via both the hanging drop method and batch crystallisation. Powder diffraction methods are used to compare these samples and to measure their resistance to radiation damage at room temperature. The X-ray induced amorphisation of the samples was followed as a function of time and it was shown that diffraction does not entirely disappear even at very long exposure times. Two distinct kinetic timescales are evident suggesting that early and late stage processes are quite different. Radiation damage was also shown to be localized in the sample in the region where the beam impinges.

  4. Noninvasive measurement of micron electron beam size of high energy using diffraction radiation

    CERN Document Server

    Naumenko, G A

    2003-01-01

    Treatments of the usage of diffraction radiation from the relativistic electrons moving though a conductive slit for the transverse beam size measurement encounter hard limitation of the method sensitivity for the electron energy larger than 1 GeV. We consider in this article a possibility of application of the artificial phase shift, which can take place when transverse electron position varies. This allows us to realize the measurements of transverse size of supper-relativistic electron beams with the small emittance.

  5. The Interaction of Optical Guided Modes with Waveguide Diffraction Gratings.

    Science.gov (United States)

    Weller-Brophy, Laura Ann

    In this thesis the results of a theoretical and experimental investigation of the coupling of guided modes by waveguide gratings are presented. This work is motivated by the potential application of waveguide gratings to integrated optical devices. The coupling of guided modes obliquely incident to both periodic and aperiodic gratings is a mechanism basic to the operation of integrated optical components such as filters, reflectors, beamsplitters, and modulators. It is shown in the Introduction to this thesis, that this mechanism is not modeled consistently by the analyses presented in the literature. For the case of TM-TM coupling, virtually each analytical treatment predicts a different value for the grating reflectivity. In addition, it is found that the typical Coupled-Mode formalisms used to derive the grating reflectivity do not offer an intuitive picture of the operation of waveguide gratings. These two particular problem areas serve as the focal points of this thesis. The latter of these is addressed through the development of a thin film model of the operation of waveguide gratings. This model presents an intuitively appealing picture of the interaction of waveguide gratings and guided modes. It also yields grating reflectivities which are in excellent agreement with those obtained through the numerical solution of the Coupled-Mode equations for both periodic and aperiodic gratings. The bulk of this research project is directed towards resolving the conflicting theoretical grating analyses presented in the literature. A new derivation of the coupling of guided modes obliquely incident to periodic gratings is presented in Chapter II of this thesis. This derivation is based on the Local Normal Mode expansion used by Marcuse for the case of normal incidence. It produces coupling coefficients which are nearly identical to those derived using the rigorous Boundary Perturbation technique. The coupling coefficients predicted by this Local Normal Mode formalism

  6. New metrology techniques improve the production of silicon diffractive optics

    Science.gov (United States)

    Brooks, Cynthia B.; Gully-Santiago, Michael; Grigas, Michelle; Jaffe, Daniel T.

    2014-07-01

    Silicon immersion gratings and grisms offer significant advantages in compactness and performance over frontsurface gratings and over grisms made from lower-index materials. At the same time, the high refractive index of Si (3.4) leads to very stringent constraints on the allowable groove position errors, typically rms error of errors and their origins, we could then implement process controls for each step. The plasma uniformity was improved for the silicon nitride mask etch process and the phase contribution of the plasma etch step was measured. We then used grayscale lithography, a technique in which the photoresist is deliberately underexposed, to measure large-scale nonuniformities in the UV exposure system to an accuracy of 3-5%, allowing us to make corrections to the optical alignment. Additionally, we used a new multiple-exposure technique combined with laser interferometry to measure the relationship between UV exposure dose and line edge shift. From these data we predict the contribution of the etching and photolithographic steps to phase error of the grating surface. These measurements indicate that the errors introduced during the exposure step dominate the contributions of all the other processing steps. This paper presents the techniques used to quantify individual process contributions to phase errors and steps that were taken to improve overall phase uniformity.

  7. 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.)

  8. Pd grating obtained by direct micromolding for use in high resolution optical diffraction based sensing

    Indian Academy of Sciences (India)

    Ritu Gupta; Giridhar U Kulkarni

    2012-10-01

    Pd grating patterns have been fabricated using the process of micromolding in capillary employing a Pd alkanethiolate precursor, which could be converted to metal in situ by thermolysis. Thus generated Pd grating were uniform in width (∼950 nm) and spacing (∼450 nm) over millimeter square areas on glass substrates. Importantly, the pattern when used as an optical grating produced a diffraction pattern with a high resolution (> 2000); the intensities of widely separated (diffraction angle, ∼26.8°) diffracted spots could be measured using a simple photodiode. By varying the concentration of Pd precursor (2mMto 25 mM), thickness of the resulting gratings could be adjusted in the range of ∼15–115 nm. By adjusting the grating parameters optimally, a maximum diffraction efficiency of 36% has been achieved. Thus fabricated Pd grating was used as seed catalyst to deposit Cu by electroless plating. The Cu deposition process has also been monitored by employing AFM, SEM and EDS analysis. The diffraction efficiency values corroborate well with the changes in the grating thickness due to Cu deposition. The grating structures presented can be reproducibly fabricated for rapidly emerging optical diffraction based sensing applications. This has been demonstrated in the case of aqueous Cu2+ by depositing the latter electrolessly on Pd.

  9. Optical substrate materials for synchrotron radiation beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Howells, M.R. [Lawrence Berkeley National Lab., CA (United States). Advanced Light Source; Paquin, R.A. [Univ. of Arizona, Tucson, AZ (United States). Optical Sciences Center

    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.

  10. Radiation from optically thin accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Tylenda, R. (Polska Akademia Nauk, Torun. Pracownia Astrofizyki)

    1981-01-01

    Accretion discs in cataclysmic variables with low rates of mass transfer, M < or approx. 10/sup 16/g s/sup -1/, have outer regions optically thin in continuum. A simple approach that allows one to calculate the radiation spectra from such discs is presented. A great number of disc models has been obtained in order to study the influence of various parameters (accretion rate, outer radius of the disc, inclination angle, mass of the accreting degenerate dwarf, viscosity parameter) of discs on the outgoing continuous spectra, emission lines and the UBV colours.

  11. Radiative transfer computations for optical beams

    CERN Document Server

    Kim, A D

    2003-01-01

    In this paper, we present a method for computing direct numerical simulations of narrow optical beam waves propagating and scattering in a plane-parallel medium. For these computations, we use Fourier and Chebyshev spectral methods for three-dimensional radiative transfer that also includes polar and azimuthal angle dependences. We treat anisotropic scattering with peaked forward scattering by using a Clenshaw-Curtis quadrature rule for the polar angle and an extended trapezoid rule for the azimuthal angle. To verify our results, we compare this spectral method to Monte Carlo simulations.

  12. Approach to improve beam quality of inter-satellite optical communication system based on diffractive optical elements.

    Science.gov (United States)

    Tan, Liying; Yu, Jianjie; Ma, Jing; Yang, Yuqiang; Li, Mi; Jiang, Yijun; Liu, Jianfeng; Han, Qiqi

    2009-04-13

    For inter-satellite optical communication transmitter with reflective telescope of two-mirrors on axis, a large mount of the transmitted energy will be blocked by central obscuration of the secondary mirror. In this paper, a novel scheme based on diffractive optical element (DOE) is introduced to avoid it. This scheme includes one diffractive beam shaper and another diffractive phase corrector, which can diffract the obscured part of transmitted beam into the domain unobscured by the secondary mirror. The proposed approach is firstly researched with a fixed obscuration ratio of 1/4. Numerical simulation shows that the emission efficiency of new figuration is 99.99%; the beam divergence from the novel inter-satellite optical communication transmitter is unchanged; and the peak intensity of receiver plane is increased about 31% compared with the typical configuration. Then the intensy patterns of receiver plane are analyzed with various obscuration ratio, the corresponding numerical modelling reveals that the intensity patterns with various obscuration ratio are nearly identical, but the amplify of relative peak intensity is getting down with the growth of obscuration ratio. This work can improve the beam quality of inter-satellite optical communication system without affecting any other functionality.

  13. OPTICAL STORAGE MECHANISM AND HIGH-ORDER DIFFRACTION PROPERTIES OF NITROAZOBENZENE-CONTAINING POLYESTER FILMS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Using Nd:YAG second harmonic pulse (100 ps), the optical storage properties of two novel polyesters, poly [4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene succinyl] and poly [2'-chloro-4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene succinyl] have been studied by multiwave mixing. The high-order diffractions of the orientation gratingsinduced by anisotropy via the reorientation of nitroazobenzene groups and optical information storage with long-term stability have been realized by multiwave mixing in their films. Up to 3rd order forward diffraction was detected in two wave mixing, while up to 4th order backward diffraction was observed in degenerated four wave mixing. The recording mechanism was explained by the trans-cis-trans isomerization cycles of azobenzene groups.The isomerization of these azobenzene groups probably undergoes with inversion mechanism under the experimental conditions. The information recorded in these films has been kept for more than 6 months.

  14. Specific features of measuring the optical power of artificial refractive and diffractive-refractive eye lenses

    Science.gov (United States)

    Lenkova, G. A.

    2016-08-01

    Methods for monitoring the optical power of artificial refractive eye lenses (intraocular lenses) based on measuring focal lengths in air and in medium are analyzed. The methods for determining the refraction of diffractive-refractive lenses (in particular, of MIOL-Akkord type), with allowance for the specific features of the diffractive structure, are considered. A computer simulation of the measurement of the focal length of MIOL-Akkord lenses is performed. The effective optical power of the diffractive component of these lenses is shown to depend on the diaphragm diameter. The optimal diaphragm diameter, at which spherical aberrations do not affect the position of foci, is found to be 3 mm. Possible errors in measuring the focal lengths are analyzed, and the necessary corrections that must be introduced into measurement results and calculations of refractions are determined.

  15. Information Storage and Retrieval for Probe Storage using Optical Diffraction Patterns

    CERN Document Server

    van Honschoten, Joost; Koelmans, Wabe W; Parnell, Thomas P; Zaboronski, Oleg V

    2011-01-01

    A novel method for fast information retrieval from a probe storage device is considered. It is shown that information can be stored and retrieved using the optical diffraction patterns obtained by the illumination of a large array of cantilevers by a monochromatic light source. In thermo-mechanical probe storage, the information is stored as a sequence of indentations on the polymer medium. To retrieve the information, the array of probes is actuated by applying a bending force to the cantilevers. Probes positioned over indentations experience deflection by the depth of the indentation, probes over the flat media remain un-deflected. Thus the array of actuated probes can be viewed as an irregular optical grating, which creates a data-dependent diffraction pattern when illuminated by laser light. We develop a low complexity modulation scheme, which allows the extraction of information stored in the pattern of indentations on the media from Fourier coefficients of the intensity of the diffraction pattern. We th...

  16. Optical diffraction studies of crystalline structures in electron micrographs. I. Theoretical considerations.

    Science.gov (United States)

    Berger, J E

    1969-12-01

    Determination of the unit cell of crystalline particles by optical diffraction analysis of electron micrographs may establish the identity and help in approximating the molecular weight of the substances contained in the crystal. This technique may be particularly helpful when isolation and purification of the crystalline material cannot be accomplished.

  17. 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.

  18. 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…

  19. Potentiality of optical diffraction grating technology in the fabrication of miniaturized multicapillary chromatographic and electrophoresis columns.

    Science.gov (United States)

    Samsonov, Y N

    2001-10-01

    A possible way of fabricating miniaturized multicapillary columns for gas and liquid chromatographs or electrophoresis devices containing many thousands of identical channels with a width (or depth) of approximately 1-30 microm by means of industrial technology for the production of optical plane reflecting diffraction gratings is proposed.

  20. Enhancement of coherent X-ray diffraction from nanocrystals by introduction of X-ray optics.

    Science.gov (United States)

    Robinson, Ian; Pfeiffer, Franz; Vartanyants, Ivan; Sun, Yugang; Xia, Younan

    2003-09-22

    Coherent X-ray Diffraction is applied to investigate the structure of individual nanocrystalline silver particles in the 100nm size range. In order to enhance the available signal, Kirkpatrick-Baez focusing optics have been introduced in the 34-ID-C beamline at APS. Concerns about the preservation of coherence under these circumstances are addressed through experiment and by calculations.

  1. 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

    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...

  2. Ion-exchanged diffractive elements in glass for substrate-mode optics.

    Science.gov (United States)

    Salmio, R P; Saarinen, J; Noponen, E

    1998-08-01

    We recently demonstrated the use of continuous-phase ion-exchanged diffractive elements in glass for free-space optics. We extend our design methods to substrate-mode optics, which permits compact packing of miniature-sized free-space optical systems. We designed one-dimensional gratings for equal-intensity 1 ? 3 and 1 ? 5 beam splitting, assuming both planar and conical incidence angles. An experimental demonstration of a 1 ? 3 beam splitter with a uniformity error of 3.4% is presented.

  3. Generation, Diffraction and Radiation of Subsonic Flexural Waves on Membranes and Plates: Observations of Structural and Acoustical Wavefields.

    Science.gov (United States)

    Matula, Thomas John

    Electromagnetic acoustic wave transducers (EMATs) are described for generating low-frequency tone bursts on metalized membranes in air and elastic plates in water. Bursts on the membrane have phase velocities much less than the speed of sound in the surrounding air and are accompanied by plane evanescent waves. The frequency and time-domain responses of the EMAT and the dependence on gap spacing between the coupling coil and the membrane were studied. Wave -number selective optical and capacitive probes were used to measure the wave properties. Versions of these transducers are insensitive to long wavelength motion of the membrane. Diffraction of the burst by a sharp edge in air was observed as a function of the gap between the membrane and a razor edge. The scattered pressure decreases exponentially with increasing gap as expected from an approximate analysis of edge diffraction of evanescent waves. In related work an EMAT is used to generate 28 kHz tone bursts of bending waves on an aluminum plate. The bursts propagate down into water where the surrounding wavefield is probed. Observations described indicate that there occurs a branching of energy as the wave crosses the air-water interface. Radiation from subsonic flexural plate waves due to the discontinuity in fluid -loading is observed. It is partially analogous to the transition radiation of fast charged particles crossing a dielectric interface. The angular radiation pattern resembles that of a line quadrupole. Near the interface there exists an interference between the two energy branches in water that produces a series of pressure nulls. The pressure nulls are associated with a pi phase change in the wavefield and are indicators of wavefront dislocations. A computation of the wavefield in an unbounded fluid due to a line-moment excitation of a plate is comparable with the null pattern observed but differs in certain details.

  4. Quantum Interferometric Optical Lithography Exploiting Entanglement to Beat The Diffraction Limit

    CERN Document Server

    Boto, A N; Williams, C P; Dowling, J P; Boto, Agedi N.; Abrams, Daniel S; Williams, Colin P.; Dowling, Jonathan P.

    1999-01-01

    Classical, interferometric, optical lithography is diffraction limited to writing features of a size lambda/4 or greater, where lambda is the optical wavelength. Using nonclassical photon number states, entangled N at a time, we show that it is possible to write features of minimum size lambda/(4N) in an N-photon absorbing substrate. This result surpasses the usual classical diffraction limit by a factor of N. Since the number of features that can be etched on a two-dimensional surface scales inversely as the square of the feature size, this allows one to write a factor of N^2 more elements on a semiconductor chip. A factor of N = 2 can be achieved easily with entangled photon pairs generated from optical parametric downconversion.

  5. 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.

  6. 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)

  7. Development of synchrotron radiation as a high-intensity source for X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Huxley, H.E. [Brandeis Univ., Rosenstiel Center, Waltham, Massachusetts (United States); Holmes, K.C. [Max-Planck-Inst. fuer Medizinische Forschung, Heidelberg (Germany)

    1997-11-01

    Interest in the molecular mechanism of muscle contraction led to the search for an intense source of X-rays of 1-2 Aa wavelength so as to be able to examine the rich X-ray diffraction patterns given by muscles during contraction. This led to the first X-ray diffraction experiments using synchrotron radiation, carried out by Holmes, Rosenbaum and Witz at DESY, Hamburg, in September 1970. In the following years, the EMBL Outstation, to utilize synchrotron radiation for biological structure determination, was established at DESY and preliminary experiments on muscle were also carried out at NINA (Daresbury). The development of time-resolved techniques for muscle diffraction was first started in the MRC Molecular Biology Laboratory in Cambridge, using rotating-anode X-ray tubes, and was then greatly extended at the EMBL Outstation, Hamburg, using the storage ring DORIS. This was a very successful venture, and helped to drive the whole technology development and to interest other potential users in the technique. (au).

  8. Fabrication of continuous diffractive optical elements using a fast tool servo diamond turning process

    Science.gov (United States)

    Zhou, Jingbo; Li, Lei; Naples, Neil; Sun, Tao; Yi, Allen Y.

    2013-07-01

    Continuous diffractive optical elements (CDOEs) can be used for laser-beam reshaping, pattern generation and can help reduce large angle scattering. Lithography, the method for the production of binary diffractive surfaces, is not suitable for fabrication of CDOEs. Diamond turning using fast tool servo, on the other hand, is a non-cleanroom method for generating continuous microstructures with high precision and efficiency. In this paper, an algorithm for designing CDOEs is introduced. The moving least-squares (MLS) method is then used to obtain the local fitting equation of the diffractive surface. Based on the MLS fitting equation, the selection of diamond cutting tool geometries (including the tool nose radius, rake angle and clearance angle) is discussed and a tool nose radius compensation algorithm is included. This algorithm is a general method for the diamond turning of complex surfaces that can be represented by a point cloud. Surface measurements and diffractive patterns generated on test samples have shown that continuous diffractive surfaces were successfully machined. In the future, CDOEs can be machined on an optical mold surface for high-volume industrial production using methods such as injection molding.

  9. Molecularly imprinted polymer diffraction grating as label-free optical bio(mimetic)sensor.

    Science.gov (United States)

    Barrios, C A; Zhenhe, C; Navarro-Villoslada, F; López-Romero, D; Moreno-Bondi, M C

    2011-01-15

    Micropatterned molecularly imprinted polymer (MIP) transmissive 2D diffraction gratings (DGs) are fabricated and evaluated as label-free antibiotic bio(mimetic)sensors. Polymeric gratings are prepared by using microtransfer molding based on SiO(2)/Si molds. The morphology of the MIP gratings is studied by optical and atomic force microscopes. MIP 2D-DGs exhibit 2D optical diffraction patterns, and measurement of changes in diffraction efficiency is used as sensor response. The refractive index of the micropatterned MIP material was estimated, via solvent index matching experiments, to be 1.486. Immersion of a MIP 2D-DG in different solutions of target-antibiotic enrofloxacin leads to significant variations in diffraction efficiency, demonstrating target-molecule detection. On the other hand, no significant response is observed for both control experiments: MIP grating exposed to a non-retained analyte and an equivalent non-imprinted polymer grating exposed to the target analyte, showing highly specific antibiotic label-free optical recognition.

  10. Double modulation of X radiation diffracted in a quartz single crystal by high and low frequency acoustic waves

    CERN Document Server

    Kocharyan, L A; Bornazyan, H S

    1986-01-01

    The time dependence of X radiation diffracted in a quartz single crystal is experimentally investigated when surface acoustic waves modulated by low frequency oscillations of different frequencies and forms are excited in the crystal.

  11. High-accuracy calibration of an adaptive optics system using a phase shifting diffraction interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Bauman, B J; Campbell, E W; Olivier, S S; Sweider, D R

    1999-06-23

    A phase-shifting diffraction interferometer (PSDI) has been integrated into an adaptive optics (AO) system developed by LLNL for use on the three meter Shane telescope at Lick Observatory. The interferometer is an all fiber optic design, which is extremely compact. It is useful for calibrating the control sensors, measuring the aberrations of the entire AO optical train, and measuring the influence functions of the individual actuators on the deformable mirror. The PSDI is particularly well suited for this application because it measures converging, quasi-spherical wavefronts, such as are produced by an AO imaging system. Thus, a PSDI can be used to measure the aberrations of the entire AO system, in-situ and without errors introduced by auxiliary optics. This provides an extremely accurate measurement ({approximately} 5 nm RMS) of the optical properties of the AO system.

  12. Neutron Diffraction and Optics of a Noncentrosymmetric Crystal. New Feasibility of a Search for Neutron EDM

    OpenAIRE

    Fedorov, V. V.; Voronin, V. V.

    2005-01-01

    Recently strong electric fields (up to 10^9 V/cm) have been discovered, which affect the neutrons moving in noncentrosymmetric crystals. Such fields allow new polarization phenomena in neutron diffraction and optics and provide, for instance, a new feasibility of a search for the neutron electric dipole moment (EDM). A series of experiments was carried out in a few last years on study of the dynamical diffraction of polarized neutrons in thick (1-10 cm) quartz crystals, using the forward diff...

  13. Time-multiplexed structured illumination using a DMD for optical diffraction tomography

    CERN Document Server

    Lee, Kyeoreh; Kim, Geon; Shin, Seungwoo; Park, YongKeun

    2016-01-01

    We present a novel illumination control technique for optical diffraction tomography (ODT). Various spatial frequencies of beam illumination were controlled by displaying time-averaged sinusoidal patterns using a digital micromirror device (DMD). Compared to the previous method using binary Lee holograms, the present method eliminates unwanted diffracted beams which may deteriorate the image quality of the ODT. We demonstrated the capability of the present method by reconstructing three-dimensional refractive index (RI) distributions of various samples, with high RI sensitivity (\\sigma_\\Delta n = 3.15 +/- 10-4), and reconstructing 3-D RI tomograms of biological samples, which provided quantitative biochemical and morphological information about the samples.

  14. Silicon-on-Insulator-Based Compact Optical Demultiplexer Employing Etched Diffraction Grating

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-Hui; TANG Yan-Zhe; WANG Yun-Xiang; QU Hong-Chang; WU Ya-Ming; LI Tie; YANG Jian-Yi; WANG Yue-Lin; LIU Ming

    2004-01-01

    A compact optical demultiplexer with etched diffraction grating (EDG) is designed and fabricated on a siliconon-insulator (SOI) material. Several 90° turning mirrors are used to bend the waveguides, and the size of the EDG-based demultiplexer is minimized to only 16 × 1.7mm2. The crosstalk is about -18 dB. The on-chip loss is about 18.2dB, which is composed of about 16.9dB excess loss and 1.3dB diffraction loss. Measures to improve the performance are discussed.

  15. PROCEEDINGS ON SYNCHROTRON RADIATION: An ART iterative reconstruction algorithm for computed tomography of diffraction enhanced imaging

    Science.gov (United States)

    Wang, Zhen-Tian; Zhang, Li; Huang, Zhi-Feng; Kang, Ke-Jun; Chen, Zhi-Qiang; Fang, Qiao-Guang; Zhu, Pei-Ping

    2009-11-01

    X-ray diffraction enhanced imaging (DEI) has extremely high sensitivity for weakly absorbing low-Z samples in medical and biological fields. In this paper, we propose an Algebra Reconstruction Technique (ART) iterative reconstruction algorithm for computed tomography of diffraction enhanced imaging (DEI-CT). An Ordered Subsets (OS) technique is used to accelerate the ART reconstruction. Few-view reconstruction is also studied, and a partial differential equation (PDE) type filter which has the ability of edge-preserving and denoising is used to improve the image quality and eliminate the artifacts. The proposed algorithm is validated with both the numerical simulations and the experiment at the Beijing synchrotron radiation facility (BSRF).

  16. Surface plasmon-polariton resonance at diffraction of THz radiation on semiconductor gratings

    CERN Document Server

    Spevak, I S; Gavrikov, V K; Shulga, V M; Feng, J; Sun, H B; Kamenev, Yu E; Kats, A V

    2013-01-01

    Resonance diffraction of THz HCN laser radiation on a semiconductor (InSb) grating is studied both experimentally and theoretically. The specular reflectivity suppression due to the resonance excitation of the THz surface plasmon-polariton is observed on a pure semiconductor grating and on semiconductor gratings covered with a thin striped layer of the residual photoresist. Presence of a thin dielectric layer on the grating surface leads to the shift and widening of the plasmon-polariton resonance. A simple analytical theory of the resonance diffraction on a shallow grating covered with a dielectric layer is presented. Its results are in a good accordance with the experimental data. Analytical expressions for the resonance shift and broadening can be useful for sensing data interpretation.

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

    NARCIS (Netherlands)

    van den Bergh, ACM; Hoving, MA; Links, TP; Dullaart, RPF; Ranchor, AV; ter Weeme, CA; Canrinus, AA; Szabo, BG; Pott, JWR

    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 thera

  18. Optical color-image encryption in the diffractive-imaging scheme

    Science.gov (United States)

    Qin, Yi; Wang, Zhipeng; Pan, Qunna; Gong, Qiong

    2016-02-01

    By introducing the theta modulation technique into the diffractive-imaging-based optical scheme, we propose a novel approach for color image encryption. For encryption, a color image is divided into three channels, i.e., red, green and blue, and thereafter these components are appended by redundant data before being sent to the encryption scheme. The carefully designed optical setup, which comprises of three 4f optical architectures and a diffractive-imaging-based optical scheme, could encode the three plaintexts into a single noise-like intensity pattern. For the decryption, an iterative phase retrieval algorithm, together with a filter operation, is applied to extract the primary color images from the diffraction intensity map. Compared with previous methods, our proposal has successfully encrypted a color rather than grayscale image into a single intensity pattern, as a result of which the capacity and practicability have been remarkably enhanced. In addition, the performance and the security of it are also investigated. The validity as well as feasibility of the proposed method is supported by numerical simulations.

  19. A Spectrometer for X-Ray Energy-Dispersive Diffraction using Synchrotron Radiation

    DEFF Research Database (Denmark)

    Staun Olsen, Janus; Buras, B; Gerward, Leif

    1981-01-01

    Describes a white-beam X-ray energy-dispersive diffractometer built for Hasylab in Hamburg, FRG, using the synchrotron radiation from the electron storage ring DORIS. The following features of the instrument are discussed: horizontal or vertical scattering plane, collimators, sample environment, ......, remote control of the goniometer, 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 YbH2 using a diamond anvil cell....

  20. Analysis of the operation of a diffraction-radiation generator with preliminary HF modulation

    Science.gov (United States)

    Pivovarova, A. G.

    1991-05-01

    The excitation conditions and output characteristics of a diffraction-radiation generator with preliminary HF modulation are determined. Attention is given to the effects of the modulation parameter, the phase shift, and the aiming distance on the displacement of the generation zone, variations of the minimum starting current, the frequency shift, the oscillation amplitude, and the efficiency of the generator. It is shown that the efficiency of a generator with preliminary HF modulation can be twice as high as that of a generator without modulation.

  1. Effect Of The Focusing Magnetostatic Field Profile On The Diffraction Radiation Oscillator Excitation

    Directory of Open Access Journals (Sweden)

    E.M. Khutoryan

    2009-01-01

    Full Text Available Effect of the focusing magnetostatic field (FMF profile on the output characteristics of diffraction radiation oscillator (DRO is studied experimentally. The laboratory prototype of the mm range DRO produced in IRE NAS of Ukraine was used in the research. Peculiarities of the output power, oscillation frequency, starting current and other DRO characteristics for the cases of the decreasing, sagging and increasing magnetostatic field along the direction of the electron flow motion were determined. Prospects for the use of the increasing FMF in DRO are shown.

  2. Extreme ultraviolet radiation for coherent diffractive imaging with high spatial resolution

    Institute of Scientific and Technical Information of China (English)

    L.V.; DAO; S.; TEICHMANN; B.; CHEN; R.A.; DILANIAN; K.B.; DINH; P.; HANNAFORD

    2010-01-01

    Using different noble gases,argon,neon and helium,we are able to generate by high-harmonic generation(HHG) just a few harmonic orders in the spectral range 10-35 nm with a photon flux of~2.10 12 photons/(harmonic cm2 s) for argon and~10 10 photons/(harmonic cm2 s) for helium. The few-harmonic-order radiation is used for coherent diffractive imaging directly without any spectral filter. A spatial resolution of~100 nm is achieved using a~30 nm HHG source.

  3. Holographic X-ray optical elements: transition between refraction and diffraction

    CERN Document Server

    Snigireva, I; Rau, C; Weitkamp, T; Aristov, V; Grigoriev, M; Kuznetsov, S; Shabelnikov, L; Yunkin, V; Hoffmann, M; Voges, E

    2001-01-01

    Planar microelectronics technology, involving photolithography and highly anisotropic plasma etching techniques, was applied to fabricate refractive and diffractive (kinoform) lenses. Focusing properties in terms of focus spot and efficiency in the energy range 8-25 keV for both types of lenses were tested at the European Synchrotron Radiation Facility (ESRF) ID22 beamline. Focal spot of 1.5 mu m with a gain of 25 was measured at 15 keV.

  4. Diffraction Radiation Diagnostics for Moderate to High Energy Charged Particle Beams

    CERN Document Server

    Fiorito, R B

    2001-01-01

    Diffraction radiation (DR) is produced when a charged particle passes throughan aperture or near a discontinuity in the media in which it is traveling. DRis closely related to transition radiation (TR), which is produced when acharged particle traverses the boundary between media with different dielectricconstants. In contrast to TR, which is now extensively used for beam diagnosticpurposes, the potential of DR as a non-interceptive, multi-parameter beamdiagnostic remains largely undeveloped. For diagnostic measurements it isuseful to observe backward reflected DR from an circular aperture or slitinclined with respect to the beam velocity. However, up to now, well foundedequations for the spectral-angular intensities of backward DR from suchapertures have not been available. We present a new derivation of the spectralangular intensity of backward DR produced from an inclined slit for twoorientations of the slit axis, i.e. perpendicular and parallel to the plane ofincidence. Our mathematical approach is genera...

  5. Observation of the stimulated coherent diffraction radiation in an open resonator at LUCX facility

    Energy Technology Data Exchange (ETDEWEB)

    Aryshev, A., E-mail: alar@post.kek.jp [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Araki, S.; Fukuda, M. [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Karataev, P. [John Adams Institute at Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom); Konkov, A.; Naumenko, G.; Potylitsyn, A. [Tomsk Polytechnic University, Institute of Physics and Technology, Lenin ave. 30, Tomsk 634050 (Russian Federation); Sakaue, K. [Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Sukhikh, L. [Tomsk Polytechnic University, Institute of Physics and Technology, Lenin ave. 30, Tomsk 634050 (Russian Federation); Terunuma, N. [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Verigin, D. [Tomsk Polytechnic University, Institute of Physics and Technology, Lenin ave. 30, Tomsk 634050 (Russian Federation); Urakawa, J. [KEK: High Energy Accelerator Research Organization,1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2014-11-01

    We present an initial test of a new type of a pre-bunched beam pumped free electron maser based on Stimulated Coherent Diffraction Radiation (SCDR) generated in an open resonator. A fast Schottky Barrier Diode (time response <1ns) has enabled us to investigate the properties of the radiation stored in the cavity as well as the intrinsic properties of the cavity itself. We observed a turn-by-turn SCDR generated by a multibunch beam. When the cavity length was exactly a half of the bunch spacing a clear resonance was observed. Moreover, turn-by-turn measurements revealed the cavity quality factor of 72.88, which was rather high for an open resonator in the wavelength range of 3–5 mm. An exponential growth of the photon intensity as a function of the number of bunches was also demonstrated.

  6. 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...

  7. Triple Bragg diffraction in paratellurite crystal

    Science.gov (United States)

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

    2017-07-01

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

  8. 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%.

  9. Optically induced lattice dynamics probed with ultrafast x-ray diffraction

    Science.gov (United States)

    Lee, H. J.; Workman, J.; Wark, J. S.; Averitt, R. D.; Taylor, A. J.; Roberts, J.; McCulloch, Q.; Hof, D. E.; Hur, N.; Cheong, S.-W.; Funk, D. J.

    2008-04-01

    We have studied the picosecond lattice dynamics of optically pumped hexagonal LuMnO3 by using ultrafast x-ray diffraction. The results show a shift and broadening of the diffraction curve due to the stimulated lattice expansion. To understand the transient response of the lattice, the measured time- and angle-resolved diffraction curves are compared to a theoretical calculation based on the dynamical diffraction theory of coherent phonon propagation modified for the hexagonal crystal structure of LuMnO3 . Our simulations reveal that a large coupling coefficient (c13) between the a-b plane and the c axis is required to fit the data. Though we interpret the transient response within the framework of thermal coherent phonons, we do not exclude the possibility of strong nonthermal coupling of the electronic excitation to the atomic framework. We compare this result to our previous coherent phonon studies of LuMnO3 in which we used optical pump-probe spectroscopy.

  10. Two-photon microscopy with diffractive optical elements and spatial light modulators

    Directory of Open Access Journals (Sweden)

    Brendon O Watson

    2010-09-01

    Full Text Available Two-photon microscopy is often performed at slow frame rates, due to the need to serially scan all points in a field of view with a single laser beam. To overcome this problem, we have developed two optical methods that split and multiplex a laser beam across the sample. In the first method a diffractive optical element (DOE generates a fixed number of beamlets that are scanned in parallel, resulting in a corresponding increase in speed, or in signal-to-noise ratio, in time-lapse measurements. The second method uses a computer-controlled spatial light modulator (SLM, to generate any arbitrary spatio-temporal light pattern. With an SLM one can image or photostimulate any predefined region of the image, such as neurons or dendritic spines. In addition, SLMs can be used to mimic a large number of optical transfer functions, including light path corrections or as adaptive optical devices.

  11. Long-baseline optical intensity interferometry: Laboratory demonstration of diffraction-limited imaging

    CERN Document Server

    Dravins, Dainis; Nuñez, Paul D

    2015-01-01

    A long-held vision has been to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, and reveal interacting gas flows in binary systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and also used for intensity interferometry. Second-order spatial coherence of light is obtained by cross correlating intensity fluctuations measured in different pairs of telescopes. With no optical links between them, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are approximately one meter, making the method practically immune to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Previous theoretical modeling has shown ...

  12. OPTICAL DIFFERENCE FREQUENCY GENERATION OF FAR INFRARED RADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.R.

    1977-07-01

    Three investigations of difference frequency generation (DFG) of far-infrared radiation by optical mixing are described: a theory of DFG by monochromatic, focused Gaussian pump laser beams, a theory of DFG by a picosecond pump laser pulse, and an experiment using ruby-pumped dye lasers. First, the theory of far-infrared generation by optical mixing of monochromatic, focused Gaussian beams in a uniaxial crystal is developed, taking into account the effects of diffraction, absorption, double refraction, and multiple reflections and total reflection at the boundary surfaces. (Reflection and transmission coefficients of a uniaxial crystal slab are derived by a new matrix technique.) Results of numerical calculations are presented. Focusing the pump beams appreciably enhances the far-infrared output despite the strong far-infrared diffraction. In a 1-cm long crystal, the optimum focal spot size is approximately equal to or smaller than the far-infrared wavelength for output frequencies less than 100 cm{sup -1}. Double refraction of the pump beams is relatively unimportant. Both far-infrared absorption and boundary reflections have major effects on the far-infrared output and its angular distribution. The former is often the factor which limits the output power. We show that a simple model treating the nonlinear polarization as a constant lie-radius Gaussian distribution of radiating dipoles adequately describes the effect of pump-beam focusing. We also compare the results of our calculations with those for second-harmonic generation. Second, a theoretical calculation of far-infrared power spectra generated by picosecond pulses in a nonlinear crystal is developed. The results are illustrated with two practical examples: LiNbO{sub 3} slabs oriented for rectification of the optical e-ray and for beating of the optical o-ray with the optical e-ray. The former is phase matched at 0 cm{sup -1}; the latter, at both the forward-(FCPM) and backward-collinear phase

  13. Experimentally observe the effect of spherical aberration on diffractive intraocular lens using adaptive optics

    Science.gov (United States)

    Guo, Huanqing; DeLestrange, Elie

    2015-03-01

    We first investigated the similarity in optical quality of a batch of diffractive intraocular lenses (DIOLs), providing experimental evidence for one DIOL as representative of a batch. Using adaptive optics, we then evaluated one DIOL under different levels of Zernike spherical aberration (SA) by applying both a point spread function test and a psychophysical visual acuity test. We found that for small aperture size SA has the effect of shifting the through-focus curve of DIOL. Also, for a relatively large aperture size, it has different effects on the distant and near foci.

  14. Design of a diffractive optical element for pattern formation in a bilingual virtual keyboard

    Science.gov (United States)

    Manouchehri, Sohrab; Rahimi, Mojtaba; Oboudiat, Mohammad

    2016-03-01

    Pattern formation is one of the many applications of diffractive optical elements (DOEs) for display. Since DOEs have lightweight and slim nature compared to other optical devices, using them as image projection device in virtual keyboards is suggested. In this paper, we present an approach to designing elements that produce distinct intensity patterns, in the far field, for two wavelengths. These two patterns are images of bilingual virtual keyboard. To achieve this with DOEs is not simple, as they are inherently wavelength specific. Our technique is based on phase periodic characteristic of wavefront using iterative algorithm to design the phase profiles.

  15. Reconstruction method for samples with refractive index discontinuities in optical diffraction tomography

    Science.gov (United States)

    Ma, Xichao; Xiao, Wen; Pan, Feng

    2017-07-01

    We present a reconstruction method for samples containing localized refractive index (RI) discontinuities in optical diffraction tomography. Abrupt RI changes induce regional phase perturbations and random spikes, which will be expanded and strengthened by existing tomographic algorithms, resulting in contaminated reconstructions. This method avoids the disturbance by recognition and separation of the discontinuous regions, and recombination of individually reconstructed data. Three-dimensional RI distributions of two fusion spliced optical fibers with different typical discontinuities are demonstrated, showing distinctly detailed structures of the samples as well as the positions and estimated shapes of the discontinuities.

  16. Pixel size and pitch measurements of liquid crystal spatial light modulator by optical diffraction

    Indian Academy of Sciences (India)

    Ravinder Kumar Banyal; B Raghavendra Prasad

    2005-08-01

    We present a simple technique for the determination of pixel size and pitch of liquid crystal (LC) based spatial light modulator (SLM). The proposed method is based on optical diffraction from pixelated LC panel that has been modeled as a two-dimensional array of rectangular apertures. A novel yet simple, two-plane measurement technique is implemented to circumvent the difficulty in absolute distance measurement. Experimental results are presented for electrically addressed twisted nematic LC-SLM removed from the display projector.

  17. Study of an athermal infrared dual band optical system design containing harmonic diffractive element

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A harmonic diffractive element (HDE) is first successfully introduced to the athermal system of infrared dual band in this paper. In this system, there are only three lens and two materials, silicon and germanium. When the temperature ranges from -70℃ to 100℃ in the dual band, it can simultaneously accomplish the rectification of the longitudinal aberration in the big field of view, as well as the wave front aberration less than 1/4 wavelength. Modulation transfer function of dual band approaches or attains the diffraction limit. The calculation results show that the spectral properties of the HDE are between refractive and diffractive elements, so we can design a simple dual-band and athermal optical system by selecting the thickness and central wavelength of the HDE exactly. Compared with a conventional refractive optical system, this system not only reduces the demand for high technical levels, but also has a compact structure, few elements, a high transmittance better aberrations performances and athermal character. At the same time, the use of the HDE also offers a new element for the infrared optics design.

  18. Mode excitation in a generator of diffraction radiation with a multistage interaction space

    Science.gov (United States)

    Miroshnichenko, V. S.; Senkevich, E. B.; Pivovarova, A. G.; Yudintsev, D. V.

    2010-08-01

    We present the results of studying theoretically and experimentally the peculiarities of mode excitation in a generator of diffraction radiation with the two- and three-cascade interaction space in one open resonator. To describe the multistage interaction mechanism, the theoretical model used considers the excitation of the TEM0nq modes, which have n in-phase field “spots,” i.e., cascades, along the direction of the electron beam motion. It is shown that even the use of the two-cascade interaction space with the TEM01q modes allows one to reduce the starting current of the generator by 1.91 times. The results of studying experimentally the two-cascade generator in the 5 and 1.5-mm wavelength ranges are presented. The in-phase property of the electron beam with the resonance field was achieved by disrupting the periodicity of the lattice slots at the center of the interaction space. The output power of the two-stage generator of 5-mm diffraction radiation in the TEM013 mode ranged from 3 to 5 W. We also observed a 4-5-fold increase in the starting current for the regime of surface waves.

  19. A diffraction correction for storage and loss moduli imaging using radiation force based elastography

    Science.gov (United States)

    Budelli, Eliana; Brum, Javier; Bernal, Miguel; Deffieux, Thomas; Tanter, Mickaël; Lema, Patricia; Negreira, Carlos; Gennisson, Jean-Luc

    2017-01-01

    Noninvasive evaluation of the rheological behavior of soft tissues may provide an important diagnosis tool. Nowadays, available commercial ultrasound systems only provide shear elasticity estimation by shear wave speed assessment under the hypothesis of a purely elastic model. However, to fully characterize the rheological behavior of tissues, given by its storage (G‧) and loss (G″) moduli, it is necessary to estimate both: shear wave speed and shear wave attenuation. Most elastography techniques use the acoustic radiation force to generate shear waves. For this type of source the shear waves are not plane and a diffraction correction is needed to properly estimate the shear wave attenuation. The use of a cylindrical wave approximation to evaluate diffraction has been proposed by other authors before. Here the validity of such approximation is numerically and experimentally revisited. Then, it is used to generate images of G‧ and G″ in heterogeneous viscoelastic mediums. A simulation algorithm based on the anisotropic and viscoelastic Green’s function was used to establish the validity of the cylindrical approximation. Moreover, two experiments were carried out: a transient elastography experiment where plane shear waves were generated using a vibrating plate and a SSI experiment that uses the acoustic radiation force to generate shear waves. For both experiments the shear wave propagation was followed with an ultrafast ultrasound scanner. Then, the shear wave velocity and shear wave attenuation were recovered from the phase and amplitude decay versus distance respectively. In the SSI experiment the cylindrical approximation was applied to correct attenuation due to diffraction effects. The numerical and experimental results validate the use of a cylindrical correction to assess shear wave attenuation. Finally, by applying the cylindrical correction G‧ and G″ images were generated in heterogeneous phantoms and a preliminary in vivo feasibility study

  20. Very high resolution optical transition radiation imaging system: Comparison between simulation and experiment

    CERN Document Server

    Bolzon, B; Aumeyr, Thomas; Boogert, Stewart Takashi; Karataev, Pavel; Kruchinin, Konstantin; Lefevre, Thibaut; Mazzoni, Stefano; Nevay, Laurence James; Shevelev, M; Terunuma, N; Urakawa, J; Welsch, Carsten

    2015-01-01

    Optical transition radiation (OTR) has become a commonly used method for 2D beam imaging measurements. In the Accelerator Test Facility 2 (ATF2) at KEK, beam sizes smaller than the OTR point spread function have been measured. Simulations of the OTR imaging system have been performed using the ZEMAX software to study the effects of optical errors such as aberrations, diffraction, and misalignments of optical components. This paper presents a comparison of simulations of the OTR point spread function with experimental data obtained at ATF2. It shows how the quantification and control of optical errors impacts on optimizing the resolution of the system. We also show that the OTR point spread function needs to be predicted accurately to optimize any optical system and to predict the error made on measurement.

  1. Very high resolution optical transition radiation imaging system: Comparison between simulation and experiment

    Directory of Open Access Journals (Sweden)

    B. Bolzon

    2015-08-01

    Full Text Available Optical transition radiation (OTR has become a commonly used method for 2D beam imaging measurements. In the Accelerator Test Facility 2 (ATF2 at KEK, beam sizes smaller than the OTR point spread function have been measured. Simulations of the OTR imaging system have been performed using the ZEMAX software to study the effects of optical errors such as aberrations, diffraction, and misalignments of optical components. This paper presents a comparison of simulations of the OTR point spread function with experimental data obtained at ATF2. It shows how the quantification and control of optical errors impacts on optimizing the resolution of the system. We also show that the OTR point spread function needs to be predicted accurately to optimize any optical system and to predict the error made on measurement.

  2. Alternative theory of diffraction grating spectral device and its application for calculation of convolution and correlation of optical pulse signals

    Science.gov (United States)

    Kazakov, Vasily I.; Moskaletz, Dmitry O.; Moskaletz, Oleg D.

    2016-04-01

    A new, alternative theory of diffraction grating spectral device which is based on the mathematical analysis of the optical signal transformation from the input aperture of spectral device to result of photo detection is proposed. Exhaustive characteristics of the diffraction grating spectral device - its complex and power spread functions as the kernels of the corresponding integral operator, describing the optical signal transformation by spectral device is obtained. On the basis of the proposed alternative theory the possibility of using the diffraction grating spectral device for calculation of convolution and correlation of optical pulse signals is showed.

  3. Special diffractive elements for optical trapping fabricated on optical fiber tips using the focused ion beam

    Science.gov (United States)

    Rodrigues Ribeiro, R. S.; Guerreiro, A.; Viegas, J.; Jorge, P. A. S.

    2016-05-01

    In this work, spiral phase lenses and Fresnel zone lenses for beam tailoring, fabricated on the tip of optical fibers, are reported. The spiral phase lenses allow tailoring the fundamental guided mode, a Gaussian beam, into a Laguerre - Gaussian profile without using additional optical elements. Whereas, the Fresnel lenses are used as focusing systems. The lenses are fabricated using Focused Ion Beam milling, enabling high resolution in the manufacturing process. The output optical intensity profiles matching the numerical simulations are presented and analyzed.

  4. 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.

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

    Science.gov (United States)

    Buranasiri, Prathan

    For two incident optical beams at different angles of incidence, a photorefractive cerium doped barium titanate crystal can facilitate different configurations of self-diffraction into higher orders. These configurations can be classified as isotropic and anisotropic, co-directional and contra-directional. Sometimes, a higher order resulting from an incident diverging object beam may comprise a converging beam, which then has the property of phase conjugation. Photorefractive fanning plays an important role in all these self-diffraction configurations. In this dissertation, we first explore the first higher order generated by forward three wave mixing. Only one higher order is observed when one of the incident beams is perpendicular to the surface of incidence. Not only the energy transfer via the first order grating has been observed but the energy transfer via the second order grating has been observed as well. With the angle between two incident beams less than 0.015 radians, the second configuration of self-diffraction has been investigated. With this configuration, codirectional isotropic self-diffraction (CODIS) and contradirectional isotropic self diffraction (CONDIS) have been observed. Phase conjugated beams which are responsible for CONDIS are the composite of mutual pumped phase conjugate (MPPC) and self pumped phase conjugate (SPPC). Due to the fanning effect, CONDIS usually forms before CODAS. In general, energy transfer between incident beams and CONDIS and CODIS occurs via first order and higher order gratings. For certain large but specific angles between the two incident extraordinarily polarized beams, it is possible to obtain anisotropic self-diffraction into ordinarily polarized higher orders. This third configuration for self-diffraction, called codirectional anisotropic self-diffraction (CODAS), can be generated most efficiently for the Bragg-matched case, although we have also observed CODAS with Bragg mismatch. In addition, CODAS has been

  6. 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.

  7. 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......-actuation requires the optimization of optical forces and optical torques that, in turn, requires the optimization of the underlying light-matter interaction [1]. We have previously proposed and demonstrated micro-targeted light-delivery and the opto-mechanical capabilities of so-called wave-guided optical...

  8. Comparative study of iterative reconstruction algorithms for missing cone problems in optical diffraction tomography.

    Science.gov (United States)

    Lim, JooWon; Lee, KyeoReh; Jin, Kyong Hwan; Shin, Seungwoo; Lee, SeoEun; Park, YongKeun; Ye, Jong Chul

    2015-06-29

    In optical tomography, there exist certain spatial frequency components that cannot be measured due to the limited projection angles imposed by the numerical aperture of objective lenses. This limitation, often called as the missing cone problem, causes the under-estimation of refractive index (RI) values in tomograms and results in severe elongations of RI distributions along the optical axis. To address this missing cone problem, several iterative reconstruction algorithms have been introduced exploiting prior knowledge such as positivity in RI differences or edges of samples. In this paper, various existing iterative reconstruction algorithms are systematically compared for mitigating the missing cone problem in optical diffraction tomography. In particular, three representative regularization schemes, edge preserving, total variation regularization, and the Gerchberg-Papoulis algorithm, were numerically and experimentally evaluated using spherical beads as well as real biological samples; human red blood cells and hepatocyte cells. Our work will provide important guidelines for choosing the appropriate regularization in ODT.

  9. Evolution of the phase singularities in edge-diffracted optical-vortex beams

    CERN Document Server

    Bekshaev, Aleksandr; Chernykh, Aleksey; Khoroshun, Anna

    2016-01-01

    We study, both theoretically and by experiment, migration of the amplitude zeros within a fixed cross section of the edge-diffracted optical-vortex beam, when the screen edge performs permanent translation in the transverse plane from the beam periphery towards the axis. Generally, the amplitude zeros (optical-vortex cores) describe spiral-like trajectories. When the screen edge advances uniformly, the motion of the amplitude zeros is not smooth and sometimes shows anomalously high rates, which make an impression of instantaneous "jumps" from one position to another. We analyze the nature, conditions and mechanism of these jumps and show that they are associated with the "birth - annihilation" topological reactions involving the optical vortex dipoles.

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

    Science.gov (United States)

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

    2015-11-01

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

  11. Generation of optical vortices with the same topological charges and controllable separation distances using diffraction gratings

    Science.gov (United States)

    Ghasempour Ardakani, Abbas; Safarzadeh, Fatemeh

    2016-08-01

    In this paper, we first generate optical vortices with different topological charges, using the method of computer-generated holograms. Then, we separate one of the optical vortices from others with a special topological charge and pass it through a diffraction grating with a specified line spacing. It is observed that the vortex beam, after passing through the grating, converts to several separated vortices with the same topological charge whose value is similar to the topological charge of the input vortex. Finally, we show that the distance between generated vortices can be controlled with the variation of spacing between grating lines. So, the proposed setup in this paper can be exploited as an optical vortex divider which is useful in communication and trapping systems.

  12. 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.

  13. Optical analysis of spatially periodic patterns in nematic liquid crystals: diffraction and shadowgraphy.

    Science.gov (United States)

    Pesch, Werner; Krekhov, Alexei

    2013-05-01

    Optical methods are most convenient for analyzing spatially periodic patterns with wave vector q in a thin layer of a nematic liquid crystal. In the standard experimental setup a beam of parallel light with a "short" wavelength λ<2π/q passes the nematic layer. Recording the transmitted light the patterns are either directly visualized by shadowgraphy or characterized more indirectly by the diffraction fringes due to the optical-grating effects of the pattern. In this work we present a systematic short-wavelength analysis of these methods for the commonly used planar orientation of the optical axis of liquid crystal at the confining surfaces. Our approach covers general three-dimensional experimental geometries with respect to the relative orientation of q and of the wave vector k of the incident light. In particular, we emphasize the importance of phase-grating effects, which are not accessible in a pure geometric optics approach. Finally, as a by-product we present also an optical analysis of convection rolls in Rayleigh-Bénard convection, where the refraction index of the fluid is isotropic in contrast to its uniaxial symmetry in nematic liquid crystals. Our analysis is in excellent agreement with an earlier physical optics approach by Trainoff and Cannell [Phys. Fluids 14, 1340 (2002)], which is restricted to a two-dimensional geometry and technically much more demanding.

  14. Large Optical Telescope Based on High Efficiency Thin Film Planar Diffractive Optics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In future ground-based receivers for deep-space optical communications with spacecraft, aperture diameters of the order of 10 meters are required even with the most...

  15. Radiation and diffraction analysis of a cylindrical body with a moon pool

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hua-wei; ZHANG Hong-sheng

    2013-01-01

    An analytical solution is presented for the radiation and the diffraction of a cylindrical body with a moon pool floating on the surface of water with a finite depth.The expressions for the potentials are obtained by the method of separation of variables,and the unknown coefficients are determined by the boundary conditions and the matching requirements on the interface.The effects of the moon pool on the hydrodynamic characteristics of the body are investigated.Some peaks are observed on the curves of the added mass and damping coefficients,corresponding to the resonant frequencies of the moon pool.The internal free surface moves like a piston at a certain low resonant frequency.

  16. On radiation damage in FIB-prepared softwood samples measured by scanning X-ray diffraction.

    Science.gov (United States)

    Storm, Selina; Ogurreck, Malte; Laipple, Daniel; Krywka, Christina; Burghammer, Manfred; Di Cola, Emanuela; Müller, Martin

    2015-03-01

    The high flux density encountered in scanning X-ray nanodiffraction experiments can lead to severe radiation damage to biological samples. However, this technique is a suitable tool for investigating samples to high spatial resolution. The layered cell wall structure of softwood tracheids is an interesting system which has been extensively studied using this method. The tracheid cell has a complex geometry, which requires the sample to be prepared by cutting it perpendicularly to the cell wall axis. Focused ion beam (FIB) milling in combination with scanning electron microscopy allows precise alignment and cutting without splintering. Here, results of a scanning X-ray diffraction experiment performed on a biological sample prepared with a focused ion beam of gallium atoms are reported for the first time. It is shown that samples prepared and measured in this way suffer from the incorporation of gallium atoms up to a surprisingly large depth of 1 µm.

  17. Acousto-optic method of spatial frequency filtration based on diffraction of two eigenmodes of a crystal

    Science.gov (United States)

    Kotov, V. M.; Averin, S. V.; Kuznetsov, P. I.; Kotov, E. V.

    2017-07-01

    A method is proposed for two-dimensional spatial frequency filtration based on acousto-optic (AO) diffraction of two eigenmodes of a crystal on a single acoustic wave. It is shown that AO filters, based on the use of such diffraction, ensure the enhancement of the two-dimensional image edge during its optical Fourier processing. The main theoretical conclusions are experimentally confirmed using an AO paratellurite filter.

  18. 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.)

  19. Development of next-generation nanolithography methods to break the optical diffraction limit

    Science.gov (United States)

    Luo, Huiwen; Wang, Liang; Qin, Jin; Ding, Li

    2016-10-01

    Photolithography has been one of the most important technologies in modern society, especially in semiconductor industry. However, due to the limitation of optical diffraction, this technique becomes more and more complex and expensive. In this paper, we experimentally study two promising techniques, near-field scanning optical lithography and nanoimprint lithography, which both have been proved to be alternatives to photolithography, and achieve sub-wavelength resolution. Taking advantage of bowtie apertures, near-field scanning optical lithography can achieve high resolution beyond the Rayleigh diffractive limit. Here, we report a novel method to fabricate bowtie aperture with sub-15 nm gap, producing highly confined electric near-field by localized surface plasmon (LSP) excitation and nanofocusing of the closely tapered gap, and obtain lithography results with 21 nm resolution (FWHM).We also develop a new plate-to-roll nanoimprint lithography (P2RNIL). Compared with plate-to-plate nanoimprint lithography (P2PNIL) and roll-to-plate nanoimprint lithography (R2PNIL), it avoids cylinder template fabrication in P2RNIL and significantly improves the productivity in P2PNIL. Our P2RNIL system can realize large-area nanoimprint continuously with high resolution and high speed.

  20. Three-dimensional deep sub-diffraction optical beam lithography with 9 nm feature size.

    Science.gov (United States)

    Gan, Zongsong; Cao, Yaoyu; Evans, Richard A; Gu, Min

    2013-01-01

    The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometre range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometre feature and resolution in optical beam lithography. Here we report on three-dimensional optical beam lithography with 9 nm feature size and 52 nm two-line resolution in a newly developed two-photon absorption resin with high mechanical strength. The revealed dependence of the feature size and the two-line resolution confirms that they can reach deep sub-diffraction scale but are limited by the mechanical strength of the new resin. Our result has paved the way towards portable three-dimensional maskless laser direct writing with resolution fully comparable to electron beam lithography.

  1. Diffractive optics development using a modified stack-and-draw technique.

    Science.gov (United States)

    Pniewski, Jacek; Kasztelanic, Rafal; Nowosielski, Jedrzej M; Filipkowski, Adam; Piechal, Bernard; Waddie, Andrew J; Pysz, Dariusz; Kujawa, Ireneusz; Stepien, Ryszard; Taghizadeh, Mohammad R; Buczynski, Ryszard

    2016-06-20

    We present a novel method for the development of diffractive optical elements (DOEs). Unlike standard surface relief DOEs, the phase shift is introduced through a refractive index variation achieved by using different types of glass. For the fabrication of DOEs we use a modified stack-and-draw technique, originally developed for the fabrication of photonic crystal fibers, resulting in a completely flat element that is easy to integrate with other optical components. A proof-of-concept demonstration of the method is presented-a two-dimensional binary optical phase grating in the form of a square chessboard with a pixel size of 5 μm. Two types of glass are used: low refractive index silicate glass NC21 and high refractive index lead-silicate glass F2. The measured diffraction characteristics of the fabricated component are presented and it is shown numerically and experimentally that such a DOE can be used as a fiber interconnector that couples light from a small-core fiber into the several cores of a multicore fiber.

  2. Diffractive-optics-based beam combination of a phase-locked fiber laser array.

    Science.gov (United States)

    Cheung, Eric C; Ho, James G; Goodno, Gregory D; Rice, Robert R; Rothenberg, Josh; Thielen, Peter; Weber, Mark; Wickham, Michael

    2008-02-15

    A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers.

  3. Proton radiation effects on optical constants of Al film reflector

    Institute of Scientific and Technical Information of China (English)

    Liu Hai; Wei Qiang; He Shi-Yu; Zhao Dan

    2006-01-01

    The Al film reflectors can yield a high-reflectance over a broad wavelength region, and have been widely used in the spacecraft optical instruments for high quality optical applications. Under the irradiation of charged particles in the Earth radiation belt, the reflectors could be deteriorated. In order to reveal the deterioration mechanism, the change in optical constants of Al film reflector induced by proton radiation with 60 keV was studied in an environment of vacuum with heat sink. Experimental results showed that when the radiation damage primarily occurs in the Al reflecting film,the extinction coefficient k will gradually decrease with increasing radiation fluence, which results in the decrease of the energies of reflective light. Therefore, the proton radiation induced an obvious degradation of spectral reflectance in the wavelength region from 200 to 800 nm on the Al film reflector.

  4. Taking X-ray Diffraction to the Limit: Macromolecular Structures from Femtosecond X-ray Pulses and Diffraction Microscopy of Cells with Synchrotron Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, H N; Miao, J; Kirz, J; Sayre, D; Hodgson, K O

    2003-10-01

    The methodology of X-ray crystallography has recently been successfully extended to the structure determination of non-crystalline specimens. The phase problem was solved by using the oversampling method, which takes advantage of ''continuous'' diffraction pattern from non-crystalline specimens. Here we review the principle of this newly developed technique and discuss the ongoing experiments of imaging non-periodic objects, like cells and cellular structures using coherent and bright X-rays from the 3rd generation synchrotron radiation. In the longer run, the technique may be applied to image single biomolecules by using the anticipated X-ray free electron lasers. Computer simulations have so far demonstrated two important steps: (1) by using an extremely intense femtosecond X-ray pulse, a diffraction pattern can be recorded from a macromolecule before radiation damage manifests itself, and (2) the phase information can be ab initio retrieved from a set of calculated noisy diffraction patterns of single protein molecules.

  5. Optical imaging of radiation-induced metabolic changes in radiation-sensitive and resistant cancer cells

    Science.gov (United States)

    Alhallak, Kinan; Jenkins, Samir V.; Lee, David E.; Greene, Nicholas P.; Quinn, Kyle P.; Griffin, Robert J.; Dings, Ruud P. M.; Rajaram, Narasimhan

    2017-06-01

    Radiation resistance remains a significant problem for cancer patients, especially due to the time required to definitively determine treatment outcome. For fractionated radiation therapy, nearly 7 to 8 weeks can elapse before a tumor is deemed to be radiation-resistant. We used the optical redox ratio of FAD/(FAD+NADH) to identify early metabolic changes in radiation-resistant lung cancer cells. These radiation-resistant human A549 lung cancer cells were developed by exposing the parental A549 cells to repeated doses of radiation (2 Gy). Although there were no significant differences in the optical redox ratio between the parental and resistant cell lines prior to radiation, there was a significant decrease in the optical redox ratio of the radiation-resistant cells 24 h after a single radiation exposure (p=0.01). This change in the redox ratio was indicative of increased catabolism of glucose in the resistant cells after radiation and was associated with significantly greater protein content of hypoxia-inducible factor 1 (HIF-1α), a key promoter of glycolytic metabolism. Our results demonstrate that the optical redox ratio could provide a rapid method of determining radiation resistance status based on early metabolic changes in cancer cells.

  6. Optical imaging of radiation-induced metabolic changes in radiation-sensitive and resistant cancer cells.

    Science.gov (United States)

    Alhallak, Kinan; Jenkins, Samir V; Lee, David E; Greene, Nicholas P; Quinn, Kyle P; Griffin, Robert J; Dings, Ruud P M; Rajaram, Narasimhan

    2017-06-01

    Radiation resistance remains a significant problem for cancer patients, especially due to the time required to definitively determine treatment outcome. For fractionated radiation therapy, nearly 7 to 8 weeks can elapse before a tumor is deemed to be radiation-resistant. We used the optical redox ratio of FAD / ( FAD + NADH ) to identify early metabolic changes in radiation-resistant lung cancer cells. These radiation-resistant human A549 lung cancer cells were developed by exposing the parental A549 cells to repeated doses of radiation (2 Gy). Although there were no significant differences in the optical redox ratio between the parental and resistant cell lines prior to radiation, there was a significant decrease in the optical redox ratio of the radiation-resistant cells 24 h after a single radiation exposure ( p = 0.01 ). This change in the redox ratio was indicative of increased catabolism of glucose in the resistant cells after radiation and was associated with significantly greater protein content of hypoxia-inducible factor 1 ( HIF - 1 ? ), a key promoter of glycolytic metabolism. Our results demonstrate that the optical redox ratio could provide a rapid method of determining radiation resistance status based on early metabolic changes in cancer cells.

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

    Science.gov (United States)

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

    2016-08-01

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

  8. Focusing and imaging properties of diffractive optical elements with star-ring topological structure

    Science.gov (United States)

    Ke, Jie; Zhang, Junyong; Zhang, Yanli; Sun, Meizhi

    2015-08-01

    A kind of diffractive optical elements (DOE) with star-ring topological structure is proposed and their focusing and imaging properties are studied in detail. The so-called star-ring topological structure denotes that a large number of pinholes distributed in many specific zone orbits. In two dimensional plane, this structure can be constructed by two constrains, one is a mapping function, which yields total potential zone orbits, corresponding to the optical path difference (OPD); the other is a switching sequence based on the given encoded seed elements and recursion relation to operate the valid zone orbits. The focusing and imaging properties of DOE with star-ring topological structure are only determined by the aperiodic sequence, and not relevant to the concrete geometry structure. In this way, we can not only complete the traditional symmetrical DOE, such as circular Dammam grating, Fresnel zone plates, photon sieves, and their derivatives, but also construct asymmetrical elements with anisotropic diffraction pattern. Similarly, free-form surface or three dimensional DOE with star-ring topological structure can be constructed by the same method proposed. In consequence of smaller size, lighter weight, more flexible design, these elements may allow for some new applications in micro and nanphotonics.

  9. Iterative Fourier transform algorithm: different approaches to diffractive optical element design

    Science.gov (United States)

    Skeren, Marek; Richter, Ivan; Fiala, Pavel

    2002-10-01

    This contribution focuses on the study and comparison of different design approaches for designing phase-only diffractive optical elements (PDOEs) for different possible applications in laser beam shaping. Especially, new results and approaches, concerning the iterative Fourier transform algorithm, are analyzed, implemented, and compared. Namely, various approaches within the iterative Fourier transform algorithm (IFTA) are analyzed for the case of phase-only diffractive optical elements with quantizied phase levels (either binary or multilevel structures). First, the general scheme of the IFTA iterative approach with partial quantization is briefly presented and discussed. Then, the special assortment of the general IFTA scheme is given with respect to quantization constraint strategies. Based on such a special classification, the three practically interesting approaches are chosen, further-analyzed, and compared to eachother. The performance of these algorithms is compared in detail in terms of the signal-to-noise ratio characteristic developments with respect to the numberof iterations, for various input diffusive-type objects chose. Also, the performance is documented on the complex spectra developments for typical computer reconstruction results. The advantages and drawbacks of all approaches are discussed, and a brief guide on the choice of a particular approach for typical design tasks is given. Finally, the two ways of amplitude elimination within the design procedure are considered, namely the direct elimination and partial elimination of the amplitude of the complex hologram function.

  10. Hyperbranched-polymer dispersed nanocomposite volume gratings for holography and diffractive optics

    Science.gov (United States)

    Tomita, Yasuo; Takeuchi, Shinsuke; Oyaizu, Satoko; Urano, Hiroshi; Fukamizu, Taka-aki; Nishimura, Naoya; Odoi, Keisuke

    2016-10-01

    We review our experimental investigations of photopolymerizable nanoparticle-polymer composites (NPCs) for holography and diffractive optics. Various types of hyperbranched polymer (HBP) were systhesized and used as transporting organic nanoparticles. These HBPs include hyperbranched poly(ethyl methacrylate) (HPEMA), hyperbranched polystyrene (HPS) and hyperbranched triazine/aromatic polymer units (HTA) whose refractive indices are 1.51, 1.61 and 1.82, respectively. Each HBP was dispersed in (meth)acrylate monomer whose refractive index was so chosen that a refractive index difference between HBP and the formed polymer was large. Such monomer-HBP syrup was mixed with a titanocene photoinitiator for volume holographic recording in the green. We used a two-beam interference setup to write an unslanted transmission volume grating at grating spacing of 1 μm and at a wavelength of 532 nm. It is shown that NPC volume gratings with the saturated refractive index modulation amplitudes as large as 0.008, 0.004 and 0.02 can be recorded in NPCs incorporated with HPEMA, HPS and HTA at their optimum concentrations of 34, 34 and 25 vol.%, respectively. We show the usefulness of HBP-dispersed NPC volume gratings for holographic applications such as holographic data storage and diffractive optical devices.

  11. Diffraction phenomenon in optical history and textbooks: Reflections on learning difficulties

    Directory of Open Access Journals (Sweden)

    Silvia Bravo

    2015-08-01

    Full Text Available This paper addresses the difficulties showed by students in the paradigm shift between geometrical optics and wave optics. It tries to interpret its origin at the university level. The research focuses on two aspects: the similarity between the fundamental ideas in the history of science and students conceptions, and the logical development of the issue in textbooks. A historical review of theories about the nature of light is developed analyzing the role of diffraction phenomenon in the paradigm shift. A characterization of the development of optics in major textbooks at university level is then performed, focusing the analysis on the way wave optics is introduced and develop. The results indicate some parallelism between students difficulties and the difficulties experienced by the scientific community in order to accept the wave model. The analysis of textbooks showed that the developmental sequence of topics and some representations used can sometimes reinforce the uncritical use of the ray-model. Finally, it is marked the importance that teachers take into account students difficulties and the interpretations about its origin for the design of educational activities and proposals.

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

    Science.gov (United States)

    Kolbe, Scott C; van der Walt, Anneke; Butzkueven, Helmut; Klistorner, Alexander; Egan, Gary F; Kilpatrick, Trevor J

    2016-01-01

    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.

  13. 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.

  14. The extraordinary radiation pattern of an optical rod antenna

    CERN Document Server

    Zhao, Chenglong

    2010-01-01

    We investigated the radiation pattern of an optical rod antenna and found that it had many features compared with its conventional radio-wave equivalents. After defining a parameter {\\Lambda} = {\\lambda}eff /{\\lambda}, which was the ratio of the effective wavelength of the rod antenna to the incident wavelength, we found that {\\Lambda} had a great influence on the radiation pattern. Even the radiation pattern with a higher resonant order is without side lobes and results in a sharper directivity, which provides new design flexibilities in improving the directivities of the optical antennas.

  15. Radiative Thermo-Refractive Noise for Transmissive Optics

    CERN Document Server

    Dwyer, Sheila

    2014-01-01

    Radiative losses have traditionally been neglected in the calculation of thermal noise of transmissive optical elements because for the most commonly used geometries they are small compared to losses due to thermal conduction. We explore the use of such transmissive optical elements in extremely noise-sensitive environments such as the arm cavities of future gravitational-wave interferometers. This drives us to a geometry regime where radiative losses are no longer negligible. In this paper we derive the thermal noise associated with such radiative losses and compare it to other known sources of thermal noise.

  16. SYNCHROTRON-RADIATION X-RAY-DIFFRACTION OF MODULATED STRUCTURES IN CHARGE-DENSITY-WAVE MATERIALS - APPLICATION TO NBSE3

    NARCIS (Netherlands)

    VANSMAALEN, S; DEBOER, JL; COPPENS, P

    1993-01-01

    Synchrotron radiation X-ray diffraction has been performed on niobium triselenide at 20K. The modulation parameters belonging to both Charge-Density-Waves (CDW's) have been determined. The high-temperature CDW is found to comprise of displacements on all atoms of column III, as well as on Se atoms o

  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. 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

  19. Measurement of integral diffraction coefficients of crystals on beamline 4B7of Beijing Synchrotron Radiation Facility

    Institute of Scientific and Technical Information of China (English)

    Yang Jia-Min; Hu Zhi-Min; Wei Min-Xi; Zhang Ji-Yan; Yi Rong-Qing; Gan Xin-Shi; Zhao Yang; Cui Ming-Qi; Zhu Tuo; Zhao Yi-Dong; Sun Li-Juan; Zheng Lei; Yan Fen

    2011-01-01

    Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt region. An experimental method has been developed to measure the integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility. The integral diffraction coefficients of several crystals including polyethylene terephthalate (PET), thallium acid phthalate (TIAP) and rubidium acid phthalate (RAP) crystals have been measured in the x-ray energy range 2100-5600 eV and compared with the calculations of the 'Darwin Prins' and the 'Mosaic' models. It is shown that the integral diffraction coefficients of these crystals are between the calculations of the 'Darwin Prins' and the 'Mosaic' models, but more close to the 'Darwin Prins' model calculations.

  20. 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

  1. Surface wave chemical detector using optical radiation

    Science.gov (United States)

    Thundat, Thomas G.; Warmack, Robert J.

    2007-07-17

    A surface wave chemical detector comprising at least one surface wave substrate, each of said substrates having a surface wave and at least one measurable surface wave parameter; means for exposing said surface wave substrate to an unknown sample of at least one chemical to be analyzed, said substrate adsorbing said at least one chemical to be sensed if present in said sample; a source of radiation for radiating said surface wave substrate with different wavelengths of said radiation, said surface wave parameter being changed by said adsorbing; and means for recording signals representative of said surface wave parameter of each of said surface wave substrates responsive to said radiation of said different wavelengths, measurable changes of said parameter due to adsorbing said chemical defining a unique signature of a detected chemical.

  2. Characterizing the decay of ancient Chinese silk fabrics by microbeam synchrotron radiation diffraction.

    Science.gov (United States)

    Hermes, A C; Davies, R J; Greiff, S; Kutzke, H; Lahlil, S; Wyeth, P; Riekel, C

    2006-03-01

    Scanning synchrotron radiation microdiffraction with an approximately 1 x 1 microm(2) beam has been used as a novel method for characterizing the decay of several T'ang dynasty (618-907 AD) silk fabrics. The crystalline fraction could be visualized based on beta-sheet 210 reflection intensities, extracted by recursive peak fits from several thousand diffraction patterns recorded during mesh scans. The azimuthal width of the 210 reflection, which is related to the orientation distribution of the crystalline domains within nanofibrils and the macroscopic orientation of the fibers traversed by the beam, was found to be sensitive to the overall state of decay of the fabric. The fine structure of the histogram of azimuthal width was related to the fiber hierarchical microstructure and the fabric morphology. SAXS/WAXS analysis supports the assumption of an initial loss of the random chain network with decay. At a subsequent state of aging, decay proceeds into the nanofibrils and the silk fibers break up into even smaller fractions.

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

    Science.gov (United States)

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

    2007-12-01

    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 Grünewald’s works. Grünewald, 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.

  4. Fibre Optical Radiation Sensing System for TESLA

    CERN Document Server

    Körfer, M

    2001-01-01

    High energy accelerators generate ionising radiation along the beam-line and at target places. This radiation is related to beam losses or dark currents. The in-situ measurement of this ionising dose that is distributed over long distances or large areas requires a new monitor system. This paper presents first results and the concept of such a monitor system at the Tesla Test Facility.

  5. Optical modulation study of repaired damage morphologies of fused silica by scalar diffraction theory

    Science.gov (United States)

    Li, Bo; Zhou, Qingyan; Jiang, Yong; Xiang, Xia; Liao, Wei; Jiang, Xiaolong; Wang, Haijun; Luan, Xiaoyu; Zheng, Wanguo; Yuan, Xiaodong

    2017-01-01

    The cone and Gaussian repaired damage craters are two typical morphologies induced by CO2 laser evaporation and nonevaporation technologies. The mathematical models are built for these two types of repaired craters, and the light modulation at 355 nm induced by the millimeter-scale repaired damage morphology is studied by scalar diffraction theory. The results show that the modulation of the Gaussian repaired morphology has one peak and then decreases with the increasing distance from 0 to 30 cm. While the modulation for cone repaired morphology remains stable after decreasing quickly with the increasing distance. When the horizontal radius increases, the modulation looks like a saw-tooth. However, the modulation has irregular variations for two kinds of morphologies with the increasing vertical depth. The simulated results agree well with experimental results. The horizontal and vertical dimensions, and downstream distance have different influences on the modulation. The risk of damage to downstream optical components can be suppressed to improve the stability of the optical system if the shape and size of repaired craters are well controlled and the positions of downstream optical components are selected appropriately.

  6. 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

    2016-08-05

    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.

  7. 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.

    2016-08-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Chirality and angular momentum in optical radiation

    CERN Document Server

    Coles, Matt M

    2012-01-01

    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 multi-mode 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...

  10. 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.

  11. Optical second-harmonic diffraction study of anisotropic surface diffusion: CO on Ni(110)

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, X.; Zhu, X.D.; Daum, W.; Shen, Y.R. (Department of Physics, University of California, Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States))

    1992-10-15

    We describe in detail a technique using optical second-harmonic (SH) diffraction from a one-dimensional laser-induced monolayer grating to probe surface diffusion of adsorbates and its anisotropy on a solid surface. The case of CO on Ni(110) is used as a demonstration. The two orthogonal and independent diffusion tensor components along (1{bar 1}0) and (001) are measured, exhibiting a strong anisotropy in both the activation energy {ital E}{sub diff} and the preexponential factor {ital D}{sub 0} in the diffusion coefficients. A compensation effect between {ital E}{sub diff} and {ital D}{sub 0} is observed. In comparison with CO/Ni(111) and CO/Ni(100), our result suggests that the Ni(110) surface seen by CO is much smoother than Ni(111) and Ni(100). Both advantages and limitations of the present technique are mentioned and possible complications in the data analysis are discussed.

  12. 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.

  13. 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.

  14. Laser-triggered high-voltage plasma switching with diffractive optics.

    Science.gov (United States)

    Ekberg, M; Sunesson, A; Bergkvist, M; Gustavsson, A; Isberg, J; Bernhoff, H; Skytt, P; Bengtsson, J; Hård, S; Larsson, M

    2001-06-01

    High-power lasers can be used to induce ionization of gases and thereby enable rapid triggering of electrical discharge devices, potentially faster than any devices based on mechanical or solid-state switching. With diffractive optical elements (DOEs) the laser light can conveniently be directed to positions within the gas so that an electrical discharge between two high-voltage electrodes is triggered reliably and rapidly. Here we report on two different types of DOE used for creating an electrical discharge in pure argon for potential high-voltage applications. One is the diffractive equivalent of a conventional axicon that yields an extended, and continuous, high-intensity focal region between the electrodes. The other is a multiple-focal-distance kinoform--a DOE that is designed to produce a linear array of 20 discrete foci, with high peak intensities, between the electrodes. We show that DOEs enable efficient, rapid switching and may provide increased flexibility in the design of novel electrode configurations.

  15. Three-dimensional shape measurement based on light patterns projection using diffractive optical elements

    Science.gov (United States)

    Twardowski, P.; Serio, B.; Raulot, V.; Guilhem, M.

    2010-05-01

    We propose a structured light micro-opto electromechanical system (MOEMS) projector specially designed to display successively a set of patterns in order to extract the 3-D shape of an object using a CCD cameras module and a small ARM-based computer for control, registration and numerical analysis. This method consists in a temporal codification using a modified Gray code combined with a classical phase shifting technique. Our approach is to combine the unambiguous and robust codification of the Gray code method with the high resolution of the phase shifting method to result in highly accurate 3D reconstructions. The proposed MOEMS is based on an array of vertical-cavity surface-emitting laser (VCSEL) combined with two planar static diffractive optical elements (DOEs) arrays. DOEs masters on quartz substrate have been fabricated using photolithography therefore replication in polycarbonate is possible at low cost. The first DOE array is designed to collimate the VCSEL light (Fresnel-type element) and the second one to project the codification patterns. DOEs have been designed and fabricated by surface etching to achieve a good diffraction efficiency using four phase levels. First we introduce the MEOMS principle and the features of the different components. We present the layout design of the DOEs and describe the issues related to the micro-fabrication process. An experimental study of the topography of the DOEs is presented and discussed. We then discuss fabrication aspects including the DOEs integration and packaging.

  16. Ultrafast Radiation Detection by Modulation of an Optical Probe Beam

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, S P; Lowry, M E

    2006-02-22

    We describe a new class of radiation sensor that utilizes optical interferometry to measure radiation-induced changes in the optical refractive index of a semiconductor sensor medium. Radiation absorption in the sensor material produces a transient, non-equilibrium, electron-hole pair distribution that locally modifies the complex, optical refractive index of the sensor medium. Changes in the real (imaginary) part of the local refractive index produce a differential phase shift (absorption) of an optical probe used to interrogate the sensor material. In contrast to conventional radiation detectors where signal levels are proportional to the incident energy, signal levels in these optical sensors are proportional to the incident radiation energy flux. This allows for reduction of the sensor form factor with no degradation in detection sensitivity. Furthermore, since the radiation induced, non-equilibrium electron-hole pair distribution is effectively measured ''in place'' there is no requirement to spatially separate and collect the generated charges; consequently, the sensor risetime is of the order of the hot-electron thermalization time {le} 10 fs and the duration of the index perturbation is determined by the carrier recombination time which is of order {approx} 600 fs in, direct-bandgap semiconductors, with a high density of recombination defects; consequently, the optical sensors can be engineered with sub-ps temporal response. A series of detectors were designed, and incorporated into Mach Zehnder and Fabry-Perot interferometer-based detection systems: proof of concept, lower detection sensitivity, Mach-Zehnder detectors were characterized at beamline 6.3 at SSRL; three generations of high sensitivity single element and imaging Fabry-Perot detectors were measured at the LLNL Europa facility. Our results indicate that this technology can be used to provide x-ray detectors and x-ray imaging systems with single x-ray sensitivity and S

  17. Radiation effects on rare-earth doped optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Girard, S.; Marcandella, C. [CEA Bruyeres-le-Chatel, DIF 91 (France); Ouerdane, Y.; Tortech, B.; Boukenter, A.; Meunier, J.P.; Vivona, M. [Lab. Hubert Curien, CNRS, 42 - Saint-Etienne (France); Vivona, M.; Robin, Th.; Cadier, B. [iXFiber SAS, 22 - lannion (France)

    2010-07-01

    In this paper, we reviewed our previous work concerning the responses of rare-earth (RE) doped fibers (Yb, Er and Er/Yb) to various types of radiations like gamma-rays, X-rays and protons. For all these harsh environments, the main measured macroscopic radiation-induced effect is an increase of the linear attenuation of these waveguides due to the generation of point defects in the RE-doped core and silica-based cladding. To evaluate the vulnerability of this class of optical fibers for space missions, we characterize the growth and decay kinetics of their radiation-induced attenuation (RIA) during and after irradiation for various compositions. Laboratory testing reveals that this class of optical fibers is very sensitive to radiations compared to passive (RE-free) samples. As a consequence, despite the small length used for space applications, the understanding of the radiation-induced effects in this class of optical fibers becomes necessary before their integration as part of fiber-based systems like gyroscopes or communication systems. In this paper, we more particularly discussed about the relative influence of the rare-earth ions (Er{sup 3+} and/or Yb{sup 3+}) and of the glass matrix dopants (Al, P, ... ) on the optical degradation due to radiations. This has been done by using a set of five prototype optical fibers designed by the fiber manufacturer iXFiber SAS to enlighten the role of these parameters. Additional spectroscopic tools like con-focal microscopy of luminescence are also used to detect possible changes in the spectroscopy of the rare-earth ions and their consequences on the functionality of the active optical fibers. (authors)

  18. Diffraction model analysis of pion-12C elastic scattering at 800 MeV/c: Optical potential by inversion

    Indian Academy of Sciences (India)

    I Ahmad; M R Arafah

    2006-03-01

    Elastic scattering of 800 MeV/c pions by 12C has been studied in the diffraction model with a view to determine pion optical potential by the method of inversion. Finding an earlier diffraction model analysis to be deficient in some respects, we propose a Glauber model based parametrization for the elastic -matrix and show that it provides an exceedingly good fit to the pion-carbon data. The proposed elastic -matrix gives a closed expression for the pion-12C optical potential by the method of inversion in the high energy approximation.

  19. Optical sub-diffraction limited focusing for confined heating and lithography

    Science.gov (United States)

    Traverso, Luis M.

    Electronics and nanotechnology is constantly demanding a decrease in size of fabricated nanoscale features. This decrease in size has become much more difficult recently due to the limited resolution of optical systems that are fundamental to many nanofabrication methods. A lot of effort has been made to fabricate devices smaller than the diffraction limit of light. Creating devices that are capable of confining fields by means of interference patterns of propagating wave modes and surface plasmon, has proven successful to confine light into smaller spot sizes. Zone plate diffraction lenses generate spots with dimensions very close to the diffraction limit. We report the fabrication of zone plates to be used in laser direct writing of silicon nanowires. We show experimentally and with numerical models that a silicon substrate subjected to a focused spot is capable of reaching the necessary temperature for the synthesis of silicon nanowires with widths of 60 nm, which is considerably smaller than the diffraction limit of the processing laser. Nanoscale ridge apertures are devices with a great potential to confine light energy. Such apertures have been experimentally proven to create very small lithography features. We believe that these apertures can be further modified in order to achieve a practical smaller confinement in the near field region. In this thesis we discuss several attempts to design and fabricate apertures with sharp edges and implement them in a previously reported parallel lithography setup. In an attempt to use apertures for parallel fabrication of patterns, we developed a system to control the position of the near-field region with respect to a lithography substrate. To do this we use a method of interferometric-spatial- phase-imaging (ISPI). With the implementation of this method we were able to produce an array of 32X32 lines with confined widths as small as 22 nm. Nanoscale ridge apertures were also studied to be used as near field transducers

  20. Optics-less Sensors for Localization of Radiation Sources

    OpenAIRE

    Caulfield, H. J.; Yaroslavsky, L. P.; Goerzen, Ch.; Umansky, S.

    2008-01-01

    A new family of radiation sensors is introduced which do not require any optics. The sensors consist of arrays of elementary sub-sensors with natural cosine-law or similar angular sensitivity supplemented with a signal processing unit that computes optimal statistical estimations of source parameters. We show, both theoretically and by computer simulation, that such sensors are capable of accurate localization and intensity estimation of a given number of radiation sources and of imaging of a...

  1. Stimulation of the human auditory nerve with optical radiation

    Science.gov (United States)

    Fishman, Andrew; Winkler, Piotr; Mierzwinski, Jozef; Beuth, Wojciech; Izzo Matic, Agnella; Siedlecki, Zygmunt; Teudt, Ingo; Maier, Hannes; Richter, Claus-Peter

    2009-02-01

    A novel, spatially selective method to stimulate cranial nerves has been proposed: contact free stimulation with optical radiation. The radiation source is an infrared pulsed laser. The Case Report is the first report ever that shows that optical stimulation of the auditory nerve is possible in the human. The ethical approach to conduct any measurements or tests in humans requires efficacy and safety studies in animals, which have been conducted in gerbils. This report represents the first step in a translational research project to initiate a paradigm shift in neural interfaces. A patient was selected who required surgical removal of a large meningioma angiomatum WHO I by a planned transcochlear approach. Prior to cochlear ablation by drilling and subsequent tumor resection, the cochlear nerve was stimulated with a pulsed infrared laser at low radiation energies. Stimulation with optical radiation evoked compound action potentials from the human auditory nerve. Stimulation of the auditory nerve with infrared laser pulses is possible in the human inner ear. The finding is an important step for translating results from animal experiments to human and furthers the development of a novel interface that uses optical radiation to stimulate neurons. Additional measurements are required to optimize the stimulation parameters.

  2. System for recording bivariate intensity distribution of optical radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vil' danov, R.R.; Deryugin, I.A.; Gladyshev, D.A.; Mirzaeu, A.T.

    1986-02-01

    This paper describes a system for recording the space-energy characteristics of optical radiation based on an MF-6 photodetector matrix and an AI-4096-3M multivariate pulse analyzer. The system can record optical images with from 2 to 64 quantization levels with visual monitoring of input data in the form of a space distribution in axonometric projection. The recording time for a complete image is from 11 to 700 msec. The system has been used to determine and monitor the crosssectional intensity distribution of laser beams as a function of radiation mode.

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

    Energy Technology Data Exchange (ETDEWEB)

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J. (Univ. of Florida, Gainesville (USA))

    1991-03-01

    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.

  4. Fabrication of diffractive optical components for an extreme ultraviolet shearing interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Spector, S.J. (Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States)); Tennant, D.M. (AT T Bell Laboratories, Holmdel, New Jersey 07733 (United States)); Tan, Z. (AT T Bell Laboratories, 510E Brookhaven National Laboratory, Upton, New York 11973 (United States)); Bjorkholm, J.E. (AT T Bell Laboratories, Holmdel, New Jersey 07733 (United States))

    1994-11-01

    We have constructed four optical components for use in an extreme ultraviolet shearing interferometer which will operate at a wavelength of 13.4 nm. The components that have been constructed include transmission diffractive optical components such as a Fresnel zone plate, angled gratings, and two-frequency gratings, as well as pinhole apertures. All the components are fabricated in 110 nm of Ge, which is supported by a 0.5--0.7-[mu]m-thick membrane of Si. The patterns were fabricated by first evaporating Ge and then spinning 100 nm polymethylmethacrylate (PMMA) onto the Si membranes. The desired patterns were exposed in the PMMA resist using electron beam lithography. Custom interative computer programs generated the patterns used to control the exposure. After developing the PMMA resist the Ge layer was etched using a reactive ion etching technique. Electron microscopy of the finished components show that the smallest features in our components are cleanly constructed, and the linewidths and placement of the features meet the desired accuracy.

  5. Spatial optical modulator (SOM): high-density diffractive laser projection display

    Science.gov (United States)

    Yun, SangKyeong; Song, JongHyeong; Yeo, InJae; Choi, YoonJoon; Yurlov, Victor; An, SeungDo; Park, HeungWoo; Yang, HaengSeok; Lee, YeongGyu; Han, KyuBum; Shyshkin, Ihar; Lapchuk, Anatoliy; Oh, KwanYoung; Ryu, SeungWon; Jang, JaeWook; Park, ChangSu; Kim, ChunGi; Kim, SunKi; Kim, EungJu; Woo, KiSuk; Yang, JeongSuong; Kim, EuiJoong; Kim, JooHong; Byun, SungHo; Lee, SeungWoo; Lim, OhkKun; Cheong, JongPil; Hwang, YoungNam; Byun, GiYoung; Kyoung, JeHong; Yoon, SangKee; Lee, JaeKwang; Lee, TaeWon; Hong, SeokKee; Hong, YoonShik; Park, DongHyun; Kang, JungChul; Shin, WooChul; Lee, SungIl; Oh, SungKyung; Song, ByungKi; Kim, HeeYeoun; Koh, ChongMann; Ryu, YungHo; Lee, HyunKee; Baek, YoungKi

    2007-02-01

    A new type of diffractive spatial optical modulators, named SOM, has been developed by Samsung Electro-Mechanics for laser projection display. It exhibit inherent advantages of fast response time and high-performance light modulation, suitable for high quality embedded laser projection displays. The calculated efficiency and contrast ratio are 75 % and 800:1 respectively in case of 0 th order, 67 % and 1000:1 respectively in case of +/-1st order. The response time is as fast as 0.7 μs. Also we get the displacement of 400 nm enough to display full color with single panel in VGA format, as being 10 V driven. Optical module with VGA was successfully demonstrated for its potential applications in mobile laser projection display such as cellular phone, digital still camera and note PC product. Electrical power consumption is less than 2 W, volume is less than 13 cc. Brightness is enough to watch TV and movie in the open air, being variable up to 6 lm. Even if it's optimal diagonal image size is 10 inch, image quality does not deteriorate in the range of 5 to 50 inch because of the merit of focus-free. Due to 100 % fill factor, the image is seamless so as to be unpleasant to see the every pixel's partition. High speed of response time can make full color display with 24-bit gray scale and cause no scan line artifact, better than any other devices.

  6. 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.

  7. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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. (LEW)

  9. Progress in Diffraction Enhanced Imaging

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

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

  10. Synchrotron radiation X-ray diffraction in situ study of fine-grained minerals in shock veins of Suizhou meteorite

    Institute of Scientific and Technical Information of China (English)

    XIE Xiande; SHU Jinfu; CHEN Ming

    2005-01-01

    The synchrotron radiation X-ray diffraction technique developed for in situ study at high pressure and temperature has also been used to investigate microscopic mineral inclusions in ultrahigh-pressure metamorphic rocks and deep-mantle samples. Present study added two more examples of successful utilization of synchrotron radiation X-ray diffraction technique for in situ investigations of fine-grained (0.5―30μm in size) minerals in very thin shock melt veins of the Suizhou meteorite: ( i ) X-ray diffraction measurement of extremely small-sized vein matrix minerals, and (ii) identification of the micron-sized new mineral tuite embedded in the vein matrix. It has been revealed that the fine-grained vein matrix consists of well crystallized garnet, kamacite and troilite, and the powder diffraction pattern consisting of 17 lines with d-values, intensities ( I ), relative intensities (I/Io) and Miller indices, as well as the cell parameters for the new mineral tuite has also been successfully obtained. The result of present investigations has enriched the content of dynamic high-pressure mineralogy and that of Earth's mantle geochemistry.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  12. 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.

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

    Science.gov (United States)

    Gan, K. K.; Buchholz, P.; Heidbrink, S.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Vogt, M.; Ziolkowski, M.

    2016-09-01

    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.

  14. Transient optical gratings for pulsed ionizing radiation studies

    CERN Document Server

    Fullagar, Wilfred K; Hall, Chris J

    2011-01-01

    Prior to the invention of holography or lasers, Bragg's X-ray microscope opened the door to optical computation in short-wavelength studies using spatially coherent visible light, including phase retrieval methods. This optical approach lost ground to semiconductor detection and digital computing in the 1960s. Since then, visible optics including spatial light modulators (SLMs), array detectors and femtosecond lasers have become widely available, routinely allowing versatile and computer-interfaced imposition of optical phase, molecular coherent control, and detection. Today, high brilliance X-ray sources begin to offer opportunities for atomic resolution and ultrafast pump-probe studies. Correspondingly, this work considers an overlooked aspect of Bragg's X-ray microscope - the incoherent ionizing radiation to coherent visible (IICV) conversion that is a necessary prerequisite for coherent optical computations. Technologies are suggested that can accomplish this conversion. Approaches to holographic data sto...

  15. Blackbody Radiation in Optically Thick Gases?

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2014-07-01

    Full Text Available In this work, the claim that optically thick gases can emit as blackbodies is refuted. The belief that such behavior exists results from an improper consideration of heat transfer and reflection. When heat is injected into a gas, the energy is primarily redistributed into translational degrees of freedom and is not used to drive emission. The average kinetic energy of the particles in the system simply increases and the temperature rises. In this respect, it is well-know that the emissivity of a gas can drop with increasing temperature. Once reflection and translation are properly considered, it is simple to understand why gases can never emit as blackbodies.

  16. 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.

  17. Interaction of pulsed CO2 laser radiation with optical materials

    Science.gov (United States)

    Schmitt, Ruediger; Hugenschmidt, Manfred; Geiss, L.; Stechele, E.

    1995-03-01

    Pulsed high power CO2-laser irradiation can cause damage to optical materials. Some results obtained at ISL with a repetitively pulsed CO2-laser with pulse energies up to 24 J are presented in this paper. In production facilities with CO2-lasers, optics transmitting in the visible spectral range like glass or PMMA are used as protection windows against scattered light. These materials have small skin depths for electromagnetic waves at 10,6 micrometers , typically in the order of some micrometers , so the interaction takes place in thin surface layers. Under high power laser radiation the transparency of the optics is lowered. On the other hand infrared transmitting optics like KCl or ZnSe show a low intrinsic absorption for CO2-laser radiation. Theoretical estimations matching with the experimental observations showed, however, that strong heating occurs, if a thin layer of inhomogeneities, typically some micrometers thick, is included in the surrounding material with slightly higher absorption than the surrounding lowless material. Under these assumptions the thermally induced stress inside the materials can explain the experimentally observed mechanical damage. Besides these thermal damage effects mechanical momenta are transferred by pulsed laser radiation to the optics. Experimental results as obtained by a ballistic pendulum are reported.

  18. A sub wavelength localization scheme in optical imaging using conical diffraction

    National Research Council Canada - National Science Library

    Rosen, Shani; Sirat, Gabriel Y; Ilan, Har'el; Agranat, Aharon J

    2013-01-01

    .... An implementation of the scheme based on the utilization of the unique phenomenon of conical diffraction is presented, and the basic strategy it provides for enhanced localization in the diffraction limited region is demonstrated.

  19. High Resolution X-Ray Diffraction of Macromolecules with Synchrotron Radiation

    Science.gov (United States)

    Stojanoff, Vivian; Boggon, Titus; Helliwell, John R.; Judge, Russell; Olczak, Alex; Snell, Edward H.; Siddons, D. Peter; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    We recently combined synchrotron-based monochromatic X-ray diffraction topography methods with triple axis diffractometry and rocking curve measurements: high resolution X-ray diffraction imaging techniques, to better understand the quality of protein crystals. We discuss these methods in the light of results obtained on crystals grown under different conditions. These non destructive techniques are powerful tools in the characterization of the protein crystals and ultimately will allow to improve, develop, and understand protein crystal growth. High resolution X-ray diffraction imaging methods will be discussed in detail in light of recent results obtained on Hen Egg White Lysozyme crystals and other proteins.

  20. 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

  1. 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.

  2. Label-free identification of white blood cell using optical diffraction tomography (Conference Presentation)

    Science.gov (United States)

    Yoon, Jonghee; Kim, Kyoohyun; Kim, Min-hyeok; Kang, Suk-Jo; Park, YongKeun

    2016-03-01

    White blood cells (WBC) have crucial roles in immune systems which defend the host against from disease conditions and harmful invaders. Various WBC subsets have been characterized and reported to be involved in many pathophysiologic conditions. It is crucial to isolate a specific WBC subset to study its pathophysiological roles in diseases. Identification methods for a specific WBC population are rely on invasive approaches, including Wright-Gimesa staining for observing cellular morphologies and fluorescence staining for specific protein markers. While these methods enable precise classification of WBC populations, they could disturb cellular viability or functions. In order to classify WBC populations in a non-invasive manner, we exploited optical diffraction tomography (ODT). ODT is a three-dimensional (3-D) quantitative phase imaging technique that measures 3-D refractive index (RI) distributions of individual WBCs. To test feasibility of label-free classification of WBC populations using ODT, we measured four subtypes of WBCs, including B cell, CD4 T cell, CD8 T cell, and natural killer (NK) cell. From measured 3-D RI tomograms of WBCs, we obtain quantitative structural and biochemical information and classify each WBC population using a machine learning algorithm.

  3. Visual outcomes and optical quality after implantation of a diffractive multifocal toric intraocular lens

    Science.gov (United States)

    Chen, Xiangfei; Zhao, Ming; Shi, Yuhua; Yang, Liping; Lu, Yan; Huang, Zhenping

    2016-01-01

    Background: This study evaluated the visual function after implantation of a multifocal toric intraocular lenses (IOLs). Materials and Methods: This study involved 10 eyes from eight cataract patients with corneal astigmatism of 1.0 diopter (D) or higher who had received phacoemulsification with implantation of an AcrySof IQ ReSTOR Toric IOL. Six-month evaluations included visual acuity, spherical equivalent (SE), defocus curve, residual astigmatism, IOL rotation, contrast sensitivity (CS), wavefront aberrations, modulation transfer function (MTF), and patient satisfaction assessments. Results: At 6 months postoperatively, uncorrected distance visual acuity (logarithm of the minimum angle of resolution) was 0.09 ± 0.04, corrected distance visual acuity was 0.02 ± 0.11, and uncorrected near visual acuity was 0.12 ± 0.07. The mean SE was −0.095 ± 0.394 D (±0.50 D in 90%). Refractive astigmatism at the 6-month follow-up visit was significantly reduced to 0.35 ± 0.32 D from 1.50 ± 0.41 D presurgery (P 0.05). There was an increase in MTF results between preoperative and postoperative evaluations at all spatial frequencies. Conclusions: The diffractive multifocal toric IOL is able to provide a predictable astigmatic correction with apparently outstanding levels of optical quality after implantation. PMID:27221680

  4. Quantification of neurotoxic effects on individual neuron cells using optical diffraction tomography (Conference Presentation)

    Science.gov (United States)

    Yoon, Jonghee; Yang, Su-a.; Kim, Kyoohyun; Park, YongKeun

    2016-03-01

    Parkinson's disease (PD) is a common neurodegenerative disease that causes symptoms of postural instability and slowness of movement. Neurodegeneration in dopaminergic neurons at the substantia nigra has been reported as pathologic features, however, detailed mechanisms underlying neurodegeneration are still remain unclear. To investigate a neurodegenerative process, various imaging tools including phase contrast microscopy, electron microscopy, and fluorescence microscopy are utilized. However, these imaging methods provide qualitative information and require invasive approaches such as the use of fluorescence agents or chemical fixation procedures that disturb normal physiological conditions of neuron cells. In order to quantify the neurodegenerative process in a non-invasive manner, we exploited optical diffraction tomography (ODT). ODT is a 3D quantitative phase imaging method that measures 3D refractive index (RI) distributions of a sample which provide quantitative structural (volume, surface area, sphericity) and biochemical (protein concentration, total cellular dry mass) information. We investigated neurotoxic effects of MPP+ on SH-SY5Y cells by using quantitative information obtained from 3D RI distributions. We also performed temporal measurements of 3D RI distributions of an individual SH-SY5Y cell to analyze neurotoxic effects on intracellular vesicle dynamics.

  5. Excimer laser ablation lithography applied to the fabrication of reflective diffractive optics

    Science.gov (United States)

    Flury, M.; Benatmane, A.; Gérard, P.; Montgomery, P. C.; Fontaine, J.; Engel, T.; Schunck, J. P.; Fogarassy, E.

    2003-03-01

    We propose a low cost technique for the production of diffractive optical elements (DOE). These elements are devoted to high power lasers beam shaping in the mid-infrared wavelengths. This process called laser ablation lithography (LAL), may seem similar to laser beam writing (LBW) in the way the whole DOE's design is reproduced pixel by pixel on the substrate placed on a computer controlled XY translation stage. A first difference is that the photoresist is not exposed with UV light but is directly ablated with short excimer laser pulses. Furthermore, with LAL technique the size of the smallest pixel ( 5 μm×5 μm) is more than 10 times greater than those produced by LBW. We discuss in details the experimental set-up for LAL and demonstrate that it gives a resolution up to 10 times greater than photolithography with flexible masks. This makes LAL a promising solution for the production of DOE for use with Nd:YAG lasers. New applications of DOEs are finally introduced with high power lasers sources, such as laser marking or multi-point brazing.

  6. The wave energy flux of high frequency diffracting beams in complex geometrical optics

    Science.gov (United States)

    Maj, Omar; Mariani, Alberto; Poli, Emanuele; Farina, Daniela

    2013-04-01

    We consider the construction of asymptotic solutions of Maxwell's equations for a diffracting wave beam in the high frequency limit and address the description of the wave energy flux transported by the beam. With this aim, the complex eikonal method is applied. That is a generalization of the standard geometrical optics method in which the phase function is assumed to be complex valued, with the non-negative imaginary part accounting for the finite width of the beam cross section. In this framework, we propose an argument which simplifies significantly the analysis of the transport equation for the wave field amplitude and allows us to derive the wave energy flux. The theoretical analysis is illustrated numerically for the case of electron cyclotron beams in tokamak plasmas by using the GRAY code [D. Farina, Fusion Sci. Technol. 52, 154 (2007)], which is based upon the complex eikonal theory. The results are compared to those of the paraxial beam tracing code TORBEAM [E. Poli et al., Comput. Phys. Commun. 136, 90 (2001)], which provides an independent calculation of the energy flow.

  7. The wave energy flux of high frequency diffracting beams in complex geometrical optics

    Energy Technology Data Exchange (ETDEWEB)

    Maj, Omar; Poli, Emanuele [Max Planck Institute for Plasma Physics, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Mariani, Alberto [Istituto di Fisica del Plasma ' P. Caldirola,' Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, via R. Cozzi 53, I-20125 Milano (Italy); Universita degli Studi di Milano, Dipartimento di Fisica, Via Celoria 16, 20133 Milano (Italy); Farina, Daniela [Istituto di Fisica del Plasma ' P. Caldirola,' Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, via R. Cozzi 53, I-20125 Milano (Italy)

    2013-04-15

    We consider the construction of asymptotic solutions of Maxwell's equations for a diffracting wave beam in the high frequency limit and address the description of the wave energy flux transported by the beam. With this aim, the complex eikonal method is applied. That is a generalization of the standard geometrical optics method in which the phase function is assumed to be complex valued, with the non-negative imaginary part accounting for the finite width of the beam cross section. In this framework, we propose an argument which simplifies significantly the analysis of the transport equation for the wave field amplitude and allows us to derive the wave energy flux. The theoretical analysis is illustrated numerically for the case of electron cyclotron beams in tokamak plasmas by using the GRAY code [D. Farina, Fusion Sci. Technol. 52, 154 (2007)], which is based upon the complex eikonal theory. The results are compared to those of the paraxial beam tracing code TORBEAM [E. Poli et al., Comput. Phys. Commun. 136, 90 (2001)], which provides an independent calculation of the energy flow.

  8. The dynamics of radiation driven, optically thick winds

    CERN Document Server

    Shen, Rong-Feng; Piran, Tsvi

    2016-01-01

    Recent observation of some luminous transient sources with low color temperatures suggests that the emission is dominated by optically thick winds driven by super-Eddington accretion. We present a general analytical theory of the dynamics of radiation pressure-driven, optically thick winds. Unlike the classical adiabatic stellar wind solution whose dynamics are solely determined by the sonic radius, here the loss of the radiation pressure due to photon diffusion also plays an important role. We identify two high mass loss rate regimes ($\\dot{M} > L_{\\rm Edd\\,}/c^2$). In the large total luminosity regime the solution resembles an adiabatic wind solution. Both the radiative luminosity, $L$, and the kinetic luminosity, $L_k$, are super-Eddington with $L < L_k$ and $L \\propto L_k^{1/3}$. In the lower total luminosity regime most of the energy is carried out by the radiation with $L_k < L \\approx L_{\\rm Edd\\,}$. In a third, low mass loss regime ($\\dot{M} < L_{\\rm Edd\\,}/c^2$), the wind becomes optically t...

  9. Research on producing high quality diffractive optical elements in volume at a low cost

    Science.gov (United States)

    Daschner, Walter

    1997-11-01

    Diffractive Optical Elements (DOEs) can be utilized in a variety of possible applications in modern optical, as well as optoelectronic systems. The current roadblock for application of DOEs in consumer products is not the feasibility of the approach, as numerous applications have been successfully demonstrated. In order for the breakthrough to occur in industry, it is important to determine a convenient and cost-effective method for manufacturing DOEs. The industry will improve the design of their legacy systems and start including DOEs only when the performance improvement (which the utilization of DOEs achieves), can be purchased with a minimal amount of additional capital investment and cost-per-part. Therefore, the focus of this dissertation was to find a cost-effective method of fabricating large quantities of DOEs with currently available fabrication tools. Direct-write approaches were investigated to fabricate high-quality masters for a subsequent replication procedure based upon molding or casting. Electron-Beam Direct-Write was carried-out in a positive Novolac-based photo-resist which provides dry etch resistivity. Another focus of this development was to find a way to minimize Electron-Beam writing time for a given element. Proximity effect characterization and compensation has been carried-out in order to increase the fidelity of the pattern reproduction. A dry-etching procedure has been developed in order to transfer resist profiles into the substrate material. During this transfer step, the etch rates of resist and substrate material can be controlled; this in turn allows a choice of final feature depth in the substrate material (depending on refractive index and wavelength in use). Two Gray-Scale masking approaches were developed to allow the cost-effective mass fabrication of DOEs in a single optical exposure step. Thin film evaporation of Inconel achieves high-quality masks at a high price. High Energy Beam Sensitive Glass, the second mask material

  10. 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.

  11. Observations on PVP-protected noble metallic nanoparticle deposits upon heating via in situ synchrotron radiation X-ray diffraction.

    Science.gov (United States)

    Song, Jenn-Ming; Chiou, Guan-Di; Chen, Wei-Ting; Chen, Shih-Yun; Kao, Tzu-Hsuan; Chen, In-Gann; Lee, Hsin-Yi

    2011-03-21

    Through monitoring the evolution of the X-ray diffraction peaks, the phase transformation of PVP-protected Ag and Au nanoparticle deposits (NPDs) on electronic substrates of Cu and Ni upon heating in air was investigated via in situ synchrotron radiation X-ray diffraction. With an increasing temperature, the broad diffraction peak of nano-sized Ag and Au particles with the original average diameters of 4.2 nm and 9.6 nm, respectively, became sharp because of particle coarsening and coalescence. Complex phase transitions among Au, Cu, AuCu(3) and CuO(x) were observed, mainly due to the negative enthalpy of mixing between Au and Cu. The interactions between NPDs and the substrates affected the shift of diffraction peaks to lower angles, caused by thermal expansion and also the temperature for the oxide formation. Compared to Au, Ag NPDs did not form intermetallic compounds with Cu and the formation of copper oxides can also be retarded mainly due to the phase separation feature of the Ag-Cu system.

  12. Evaluation of atomic constants for optical radiation, volume 1

    Science.gov (United States)

    Kylstra, C. D.; Schneider, R. J.

    1974-01-01

    Atomic constants for optical radiation are discussed which include transition probabilities, line strengths, and oscillator strengths for both dipole and quadrupole transitions, as well as the associated matrix elements needed for line broadening calculations. Atomic constants were computed for a wide selection of elements and lines. An existing computer program was used, with modifications to include, in an approximate manner, the effect of equivalent electrons, and to enable reordering and restructuring of the output for publication. This program is suitable for fast, low cost computation of the optical constants, using the Coulomb approximation formalism for LS coupling.

  13. X-Ray induced radiation damage in taurine: a combined X-ray diffraction and Raman study.

    Science.gov (United States)

    Beukes, J A; Mo, F; van Beek, W

    2007-09-07

    The impact of X-radiation on crystalline taurine has been investigated by time resolved synchrotron X-ray powder and single crystal diffraction and Raman spectroscopy. Multiple data sets have been collected at 120 and 296 K. All the observed effects of radiation, i.e. broadening and shifts of Raman and diffraction lines, a dose dependent irreversible increase in the atomic displacement parameters (ADPs) as well as in one of the unit-cell axes, and an apparent enhancement of electron density in the SO(3) group can be tentatively attributed to primary radical formation predominantly involving the SO(3) group. In secondary reactions molecular species that are distinct from taurine are created in minute quantities, thereby introducing local departure from crystalline order, i.e. enhanced static disorder and a build-up of local strain. Our study provides evidence for ascribing the linear increase in ADPs as well as the expansion of the c axis to the accumulation of foreign species in the crystal, and not to a thermal effect. Once initiated, this process appears to continue also without radiation, however, then at a much reduced rate.

  14. 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.)

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

    Science.gov (United States)

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

    2009-09-15

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

  16. Very High Resolution Solar X-ray Imaging Using Diffractive Optics

    Science.gov (United States)

    Dennis, B. R.; Skinner, G. K.; Li, M. J.; Shih, A. Y.

    2012-01-01

    This paper describes the development of X-ray diffractive optics for imaging solar flares with better than 0.1 arcsec angular resolution. X-ray images with this resolution of the greater than or equal to 10 MK plasma in solar active regions and solar flares would allow the cross-sectional area of magnetic loops to be resolved and the coronal flare energy release region itself to be probed. The objective of this work is to obtain X-ray images in the iron-line complex at 6.7 keV observed during solar flares with an angular resolution as fine as 0.1 arcsec - over an order of magnitude finer than is now possible. This line emission is from highly ionized iron atoms, primarily Fe xxv, in the hottest flare plasma at temperatures in excess of approximately equal to 10 MK. It provides information on the flare morphology, the iron abundance, and the distribution of the hot plasma. Studying how this plasma is heated to such high temperatures in such short times during solar flares is of critical importance in understanding these powerful transient events, one of the major objectives of solar physics.We describe the design, fabrication, and testing of phase zone plate X-ray lenses with focal lengths of approximately equal to 100 m at these energies that would be capable of achieving these objectives. We show how such lenses could be included on a two-spacecraft formation-flying mission with the lenses on the spacecraft closest to the Sun and an X-ray imaging array on the second spacecraft in the focal plane approximately equal to 100 m away. High resolution X-ray images could be obtained when the two spacecraft are aligned with the region of interest on the Sun. Requirements and constraints for the control of the two spacecraft are discussed together with the overall feasibility of such a formation-flying mission.

  17. 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.

  18. Local study of fissure caries by Fourier transform infrared microscopy and X-ray diffraction using synchrotron radiation.

    Science.gov (United States)

    Seredin, Pavel; Kashkarov, Vladimir; Lukin, Anatoliy; Ippolitov, Yury; Julian, Robert; Doyle, Stephen

    2013-09-01

    Investigations of intact dental enamel as well as carious-affected human dental enamel were performed using infrared spectromicroscopy and X-ray diffraction applying synchrotron radiation. Caries of enamel was shown to be characterized by an increase in the number of deformation and valence vibrations for N-C-O, N-H and C=O bonds, a decrease of the crystallinity index, and by the absence of the preferable orientation of hydroxyapatite crystals within the affected enamel. This indicates the presence of destructive processes in the organic matrix of hard tooth tissues.

  19. 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.

  20. Optically Thin Metallic Films for High-radiative-efficiency Plasmonics

    CERN Document Server

    Yang, Yi; Hsu, Chia Wei; Miller, Owen D; Joannopoulos, John D; Soljačić, Marin

    2016-01-01

    Plasmonics enables deep-subwavelength concentration of light and has become important for fundamental studies as well as real-life applications. Two major existing platforms of plasmonics are metallic nanoparticles and metallic films. Metallic nanoparticles allow efficient coupling to far field radiation, yet their synthesis typically leads to poor material quality. Metallic films offer substantially higher quality materials, but their coupling to radiation is typically jeopardized due to the large momentum mismatch with free space. Here, we propose and theoretically investigate optically thin metallic films as an ideal platform for high-radiative-efficiency plasmonics. For far-field scattering, adding a thin high-quality metallic substrate enables a higher quality factor while maintaining the localization and tunability that the nanoparticle provides. For near-field spontaneous emission, a thin metallic substrate, of high quality or not, greatly improves the field overlap between the emitter environment and ...

  1. Local Radiative Hydrodynamic and Magnetohydrodynamic Instabilities in Optically Thick Media

    CERN Document Server

    Blaes, Omer M; Blaes, Omer; Socrates, Aristotle

    2003-01-01

    We examine the local conditions for radiative damping and driving of short wavelength, propagating hydrodynamic and magnetohydrodynamic (MHD) waves in static, optically thick, stratified equilibria. We show that so-called strange modes in stellar oscillation theory and magnetic photon bubbles are intimately related and are both fundamentally driven by the background radiation pressure acting on density and opacity fluctuations in compressible waves. We identify the necessary criteria for unstable driving of these waves, and show that this driving can exist in both gas and radiation pressure dominated media, as well as pure Thomson scattering media in the MHD case. We discuss the physical origin of these instabilities, and briefly describe the conditions under which they might be manifested in both stellar envelopes and accretion disks.

  2. Optical Cherenkov radiation in ultrafast cascaded second-harmonic generation

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin

    2010-01-01

    the dispersive wave. Finally, an investigation of recent experimental results uncovers a four-wave-mixing phenomenon related to Cherenkov radiation that is an additional generation mechanism of long-wavelength radiation that can occur during soliton compression. We discuss the conditions that lead......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....... 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...

  3. 3D laser inspection of fuel assembly grid spacers for nuclear reactors based on diffractive optical elements

    Science.gov (United States)

    Finogenov, L. V.; Lemeshko, Yu A.; Zav'yalov, P. S.; Chugui, Yu V.

    2007-06-01

    Ensuring the safety and high operation reliability of nuclear reactors takes 100% inspection of geometrical parameters of fuel assemblies, which include the grid spacers performed as a cellular structure with fuel elements. The required grid spacer geometry of assembly in the transverse and longitudinal cross sections is extremely important for maintaining the necessary heat regime. A universal method for 3D grid spacer inspection using a diffractive optical element (DOE), which generates as the structural illumination a multiple-ring pattern on the inner surface of a grid spacer cell, is investigated. Using some DOEs one can inspect the nomenclature of all produced grids. A special objective has been developed for forming the inner surface cell image. The problems of diffractive elements synthesis, projecting optics calculation, adjusting methods as well as calibration of the experimental measuring system are considered. The algorithms for image processing for different constructive elements of grids (cell, channel hole, outer grid spacer rim) and the experimental results are presented.

  4. Application of the method of auxiliary sources in optical diffraction microscopy

    DEFF Research Database (Denmark)

    Karamehmedovic, Mirza; Sørensen, Mads Peter; Hansen, Poul-Erik

    2010-01-01

    The Method of Auxiliary Sources is used for characterisation of grating defects. Grating profiles are characterised by best fit matching of a library of diffraction efficiencies with numerical simulated diffraction efficiencies with defects. It is shown that the presented method can solve...

  5. Surface diffusion of CO on Ni(111) studied by diffraction of optical second-harmonic generation off a monolayer grating

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X.D.; Rasing, T.; Shen, Y.R.

    1988-12-19

    Diffraction of optical second-harmonic generation from a monolayer grating created by laser desorption of adsorbates can be used to study surface diffusion of molecules on substrates. Application of this novel technique to CO on Ni(111) yields a diffusion activation energy of 6.9 kcal/mol and a preexponential factor of approx. =1.2 x 10/sup -5/ cm/sup 2/s/sup -1/.

  6. 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).

  7. Optical Synchrotron Radiation Beam Imaging with a Digital Mask

    Energy Technology Data Exchange (ETDEWEB)

    Fiorito, R. B. [University of Maryland, College Park, MD (United States); Zhang, H. D. [University of Maryland, College Park, MD (United States); Corbett, W. J. [SLAC, Menlo Park, CA (United States); Fisher, A. S. [SLAC, Menlo Park, CA (United States); Mok, W. Y. [SLAC, Menlo Park, CA (United States); Tian, K. [SLAC, Menlo Park, CA (United States); Douglas, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wilson, F. G. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Mitsuhashi, T. M. [KEK, Tsukuba (Japan); Shkvarunets, A. G. [University of Maryland, College Park, MD (United States)

    2012-11-01

    We have applied a new imaging/optical masking technique, which employs a digital micro-mirror device (DMD) and optical synchrotron radiation (OSR), to perform high dynamic range (DR) beam imaging at the JLAB Energy Recovery Linac and the SLAC/SPEAR3 Synchrotron Light Source. The OSR from the beam is first focused onto the DMD to produce a primary image; selected areas of this image are spatially filtered by controlling the state of individual micro-mirrors; and finally, the filtered image is refocused onto a CCD camera. At JLAB this technique has been used successfully to view the beam halo with a DR ~ 105. At SPEAR3 the DMD was used to filter out the bright core of the stored beam to study the turn-by-turn dynamics of the 10-3 weaker injected beam. We describe the optical performance, present limitations and our plans to improve the DR of both experimental systems.

  8. Comparison of two methods for equalising the diffraction efficiency of different spatial frequency components of holographic optical elements

    Science.gov (United States)

    Keshri, S.; Murphy, K.; Toal, V.; Naydenova, I.; Martin, S.

    2017-05-01

    A volume cylindrical holographic lens is fabricated in a photopolymer material to obtain a simple, lightweight and inexpensive lens which can collimate a diverging light beam. For a collimated beam, it is necessary to have uniform intensity across the beam diameter and to achieve equal diffraction efficiency for different regions of the cylindrical holographic lens, two methods are discussed. In the first method, the diffraction efficiency is improved by modifying the recording geometry in order to operate at a range of spatial frequencies for which the photopolymer provides higher diffraction efficiency. In the second method, the recording has been carried out with varying laser power and exposure time while keeping the exposure energy constant, in order to improve the material's performance at the lower spatial frequencies. The second approach increases the uniformity of diffraction efficiency across the Holographic optical elements (HOEs) even when low spatial frequency components are present. The results obtained provide cylindrical holographic lenses with overall higher and uniform diffraction efficiency. This type of lens has the potential to be used in combination with LED sources and different lighting applications.

  9. First diffraction topographic results at a third generation synchrotron radiation facility: application to crystals under an electric field

    Energy Technology Data Exchange (ETDEWEB)

    Rejmankova, P. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France); Baruchel, J. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)

    1995-05-01

    Diffraction topographic techniques allow the observation of inhomogeneities (defects, domains,..) within a single crystal. The unique capabilities of third generation synchrotron radiation facilities, like the ESRF, add new possibilities to these techniques: (1) the exposure time to record a topograph can be reduced to similar 10{sup -2} s, i.e. a factor 10{sup 2}-10{sup 3} below the present standards; (2) an improved resolution associated with the small source size, even when setting the film far ( similar 60 cm) from the sample, allows the size of the sample environment devices to be increased; (3) high sensitivity to small ({>=}10{sup -7}) distortions (misorientations and/or lattice parameter variations); (4) investigation of thick or heavy materials, which were up to now the exclusive field of neutron diffraction. We briefly describe the future Topography and High Resolution Diffraction beamline ID 19, which is designed to optimize the required experimental conditions, and which will be operational at the end of 1995. The first topographic white beam experiments which illustrate these new possibilities were carried out on two (ID11 and D5) of the presently operational beamlines of the ESRF. In this work, particular attention is dedicated to observations performed on crystals under an electric field ({alpha}-LiIO{sub 3}, KTP, LiNbO{sub 3}). Very interesting and encouraging results were obtained, particularly when using ``section`` topography. (orig.).

  10. Synchrotron radiation X-ray multiple diffraction in the study of KDP phase transition induced by electric field

    Directory of Open Access Journals (Sweden)

    A.O. dos Santos

    2001-01-01

    Full Text Available In this work, the application of the X-ray multiple diffraction technique using synchrotron radiation at Laboratório Nacional de Luz Síncrotron (LNLS to study KDP phase transition induced by electric field is discussed. A Huber three-axis (omega, phi, 2theta diffractometer mounted on a table which rotates around the incident beam allows to measure Renninger scans (RS at the XRD station of LNLS using the adequate polarization for the experiments. Prior results indicated (080 as the best choice for the KDP primary reflection and the (440( 40 four-beam case for the secondary. Two Bragg-surface diffraction (BSD reflections, where the secondary beam is propagated parallel to the sample surface, are involved in this multiple diffraction case. A RS interval of 3.3° around phi = 0° position was measured while the electric field was increased up to 6 kV/cm. At this value, a phase transition was observed and the secondary peaks became narrower and changed their RS position indicating possible occurrence of a metastable ferroelectric phase.

  11. Mechanisms of Radiation Damage Generated by Ionizing Radiation in Optical Waveguides

    Science.gov (United States)

    1988-09-01

    SUMMARY OF APPENDIX B "Optical scattering and SPR study of ZBLAN glass : Dependence on preparation and processing methods" LMater. Sci. Forum 19-20...studied the types of centers created by ionizing radiation in ZBLAN (ZrF 4, BaF 2 , LaF 3, AlF 3 , and NaF) glass . Samples of ZBLAN were prepared using...radiation-induced centers in ZBLAN glass depend strongly on the glass -processing conditions. For example, ZBLAN glasses processed with CC14 yield paramagnetic

  12. Optical synchrotron radiation beam imaging with a digital mask

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hao [Univ. of Maryland, College Park, MD (United States); Fiorito, Ralph [Univ. of Maryland, College Park, MD (United States); Corbett, Jeff [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shkvarunets, Anatoly [Univ. of Maryland, College Park, MD (United States); Tian, Kai [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fisher, Alan [SLAC National Accelerator Lab., Menlo Park, CA (United States); Douglas, D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wilson, F. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mok, W. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mitsuhashi, T. [KEK, Tsukuba (Japan)

    2016-01-01

    The 3GeV SPEAR3 synchrotron light source operates in top-up injection mode with up to 500mA circulating in the storage ring (equivalently 392nC). Each injection pulse contains only 40-80 pC producing a contrast ratio between total stored charge and injected charge of about 6500:1. In order to study transient injected beam dynamics during User operations, it is desirable to optically image the injected pulse in the presence of the bright stored beam. In the present work this is done by re-imaging visible synchrotron radiation onto a digital micro-mirror-array device (DMD), which is then used as an optical mask to block out light from the bright central core of the stored beam. The physical masking, together with an asynchronously-gated, ICCD imaging camera makes it is possible to observe the weak injected beam component on a turn-by-turn basis. The DMD optical masking system works similar to a classical solar coronagraph but has some distinct practical advantages: i.e. rapid adaption to changes in the shape of the stored beam, high extinction ratio for unwanted light and minimum scattering from the primary beam into the secondary optics. In this paper we describe the DMD masking method, features of the high dynamic range point spread function for the SPEAR3 optical beam line and measurements of the injected beam in the presence of the stored beam.

  13. Superresolved optical imaging through higher-order spatial frequency harmonic generation without beating the diffraction limit of light

    CERN Document Server

    Li, Zhixiang; Zhang, Guoquan

    2016-01-01

    We proposed a method to achieve superresolved optical imaging without beating the diffraction limit of light. This is achieved by magnifying the ideal optical image of the object through higher-order spatial frequency generation while keeping the size of the effective point spread function of the optical imaging system unchanged. A proof-of-principle experiment was demonstrated in a modified $4f$-imaging system, where the spatial frequency of a two-line source was doubled or tripled on the confocal Fourier plane of the $4f$-imaging system through a light pulse storage and retrieval process based on the electromagnetically induced transparency effect in a Pr$^{3+}$:$\\rm Y_2SiO_5$ crystal, and an originally unresolvable image of the two line sources in the conventional $4f$-imaging system became resolvable with the spatial frequency doubling or tripling. Our results offer an original way towards improving optical imaging resolution without beating the diffraction limit of light, which is totally different from ...

  14. X-ray detectors for diffraction studies and their use with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. 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.

  16. 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.

  17. Radiation optic neuropathy and retinopathy with low dose (20 Gy radiation treatment

    Directory of Open Access Journals (Sweden)

    Crandall E. Peeler

    2016-10-01

    Conclusions and importance: Though cumulative radiation doses to the anterior visual pathway of less than 50 Gy are traditionally felt to be safe, it is important to consider not just the total exposure but also the size of individual fractions. The single-dose threshold for RON in proton beam treatment has yet to be defined. Our case suggests that fractions of less than 10 Gy should be delivered to minimize the risk of optic nerve injury.

  18. Low cost and high performance GPON, GEPON and RFoG optical network pentaplexer module design using diffractive grating approach

    Science.gov (United States)

    Chen, I.-Ju; Chi, Chang-Chia; Tarn, Chen-Wen

    2016-01-01

    A new architecture of a pentaplexer transceiver module which can be used in GPON/GEPON and RFoG triple play optical networks with supporting of the multiple optical wavelengths of 1310 nm, 1490 nm, 1550 nm, 1610 nm, and 1650 nm, is proposed. By using diffractive grating elements combing with market readily available GRIN (Gradient-Index) lens, grating, mirrors, beamsplitter, LDs (Laser Diodes), and PDs (Photodetectors), the proposed design have the advantages of low cost, high efficiency/performance, easy design and manufacturing, over the contemporary triplex transceivers which are made of multilayer filters or waveguides that increase the complexity of manufacturing and reduce the performance efficiency. With the proposed design, a pentaplexer system can accommodate GPON/GEPON, RFoG, and monitoring integration services, total five optical wavelength channels into a hybrid-integrated TO-CAN package platform with sufficient efficiency.

  19. Controllable vacuum-induced diffraction of matter-wave superradiance using an all-optical dispersive cavity

    Science.gov (United States)

    Su, Shih-Wei; Lu, Zhen-Kai; Gou, Shih-Chuan; Liao, Wen-Te

    2016-10-01

    Cavity quantum electrodynamics (CQED) has played a central role in demonstrating the fundamental principles of the quantum world, and in particular those of atom-light interactions. Developing fast, dynamical and non-mechanical control over a CQED system is particularly desirable for controlling atomic dynamics and building future quantum networks at high speed. However conventional mirrors do not allow for such flexible and fast controls over their coupling to intracavity atoms mediated by photons. Here we theoretically investigate a novel all-optical CQED system composed of a binary Bose-Einstein condensate (BEC) sandwiched by two atomic ensembles. The highly tunable atomic dispersion of the CQED system enables the medium to act as a versatile, all-optically controlled atomic mirror that can be employed to manipulate the vacuum-induced diffraction of matter-wave superradiance. Our study illustrates a innovative all-optical element of atomtroics and sheds new light on controlling light-matter interactions.

  20. Optically confined polarized resonance Raman studies in identifying crystalline orientation of sub-diffraction limited AlGaN nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Sivadasan, A. K., E-mail: sivankondazhy@gmail.com; Patsha, Avinash; Dhara, Sandip, E-mail: dhara@igcar.gov.in [Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2015-04-27

    An optical characterization tool of Raman spectroscopy with extremely weak scattering cross section tool is not popular to analyze scattered signal from a single nanostructure in the sub-diffraction regime. In this regard, plasmonic assisted characterization tools are only relevant in spectroscopic studies of nanoscale object in the sub-diffraction limit. We have reported polarized resonance Raman spectroscopic (RRS) studies with strong electron-phonon coupling to understand the crystalline orientation of a single AlGaN nanowire of diameter ∼100 nm. AlGaN nanowire is grown by chemical vapor deposition technique using the catalyst assisted vapor-liquid-solid process. The results are compared with the high resolution transmission electron microscopic analysis. As a matter of fact, optical confinement effect due to the dielectric contrast of nanowire with respect to that of surrounding media assisted with electron-phonon coupling of RRS is useful for the spectroscopic analysis in the sub-diffraction limit of 325 nm (λ/2N.A.) using an excitation wavelength (λ) of 325 nm and near ultraviolet 40× far field objective with a numerical aperture (N.A.) value of 0.50.

  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. Exceptionally strong Bragg diffraction from a mesoporous silica film pretreated with chlorotrimethylsilane toward application in X-ray optics.

    Science.gov (United States)

    Kubo, Wataru; Takahashi, Masahiko; Komoto, Atsushi; Okamoto, Kohei; Miyata, Hirokatsu

    2012-01-28

    Exceptionally strong Bragg diffraction from a mesoporous silica film is achieved by exposing the as-deposited film to vapor of chlorotrimethylsilane (Me(3)SiCl) before extracting the surfactant. The intensity of the X-ray diffraction peak increased 7 times after the surfactant removal and it approached 30% reflectivity. This large increase of diffraction intensity cannot be explained simply by the improved contrast of the electron density, and rearrangement of the pore wall during the Me(3)SiCl vapor treatment is suggested. It is shown by infrared spectroscopy that Me(3)SiCl with a high grafting reactivity effectively caps the silanol groups and prevents the following condensation, which causes the structural degradation. The substitution of the hydrogen atom of hydroxyl groups with trimethylsilyl groups should help the improvement of the structural regularity by reducing the hydrogen bonds in the pore wall. The achieved strong diffraction opens the gate for the application of these regular mesoporous films prepared by a self-assembly process to optical elements in the X-ray region.

  3. Laser-heating-based active optics for synchrotron radiation applications

    CERN Document Server

    Yang, Fugui; Zhang, Xiaowei

    2016-01-01

    Active optics has attracted considerable interest from researchers in synchrotron radiation facilities, because of its capacity for x-ray wavefront correction. Here, we report a novel and efficient technique for correcting or modulating a mirror surface profile based on laser-heating-induced thermal expansion. An experimental study of the characteristics of the surface thermal deformation response indicates that the power of a milliwatt laser yields a bump height as low as sub-nanometer scale, and that variation of the spot size modulates the response function width effectively. In addition, the capacity of the laser-heating technique for free-form surface modulation is demonstrated via a surface correction experiment. The developed method is a promising new approach towards effective x-ray active optics coupled with at-wavelength metrology techniques.

  4. Optical fiber transmission of high power excimer laser radiation.

    Science.gov (United States)

    Pini, R; Salimbeni, R; Vannini, M

    1987-10-01

    An experimental investigation of optical fiber transmission of high power excimer laser radiation is presented. Different types of commercially available UV fiber have been tested, measuring energy handling capabilities and transmission losses of short samples at the XeCl (308-nm) and KrF (249-nm) wavelengths by using a standard excimer laser. A power density dependent damage process has been observed over 1 GW/cm(2). Fiber losses due to different radii of curvature are also reported. Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose. Finally, optimum excimer laser characteristics to increase the energy coupling in fibers are discussed.

  5. Optical substrate materials for synchrotron radiation beam lines

    Science.gov (United States)

    Howells, Malcolm R.; Paquin, Roger A.

    1997-09-01

    We consider the materials choices available for making optical substrates for synchrotron radiation beam lines. We 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 we explore the issues of dimensional stability, polishing, bending, cooling, and manufacturing strategy. We conclude that metals are best from an engineering and cost standpoint while the ceramics are best from a polishing standpoint. We then give discussions of specific materials as follows: silicon carbide, silicon, electroless nickel, GlidcopTM, aluminum, precipitation- hardening stainless steel, mild steel, invar and superinvar. Finally we summarize conclusions and propose ideas for further research.

  6. Radiation-hard/high-speed array-based optical engine

    Science.gov (United States)

    Gan, K. K.; Buchholz, P.; Heidbrink, S.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Vogt, M.; Ziolkowski, M.

    2016-12-01

    We have designed and fabricated a compact array-based optical engine for transmitting data at 10 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 DAC settings are stored in SEU (single event upset) tolerant registers. Several devices were irradiated with 24 GeV/c protons and the performance of the devices is satisfactory after the irradiation.

  7. Optical and radiographical characterization of silica aerogel for Cherenkov radiator

    CERN Document Server

    Tabata, Makoto; Hatakeyama, Yoshikiyo; Kawai, Hideyuki; Morita, Takeshi; Nishikawa, Keiko

    2012-01-01

    We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.

  8. First characterization of coherent optical vortices from harmonic undulator radiation.

    Science.gov (United States)

    Hemsing, E; Dunning, M; Hast, C; Raubenheimer, T; Xiang, Dao

    2014-09-26

    We describe the experimental generation and measurement of coherent light that carries orbital angular momentum from a relativistic electron beam radiating at the second harmonic of a helical undulator. The measured helical phase of the light is shown to be in agreement with predictions of the sign and magnitude of the phase singularity and is more than 2 orders of magnitude greater than the incoherent signal. Our setup demonstrates that such optical vortices can be produced in modern free-electron lasers in a simple afterburner arrangement for novel two-mode pump-probe experiments.

  9. Use of rigorous vector coupled-wave theory for designing and tolerancing surface-relief diffractive components for magneto-optical heads

    Science.gov (United States)

    Haggans, Charles W.; Kostuk, Raymond K.

    1991-01-01

    A rigorous coupled wave model is presented, experimentally validated, and used for tolerancing surface relief diffractive elements. Applications of the model in the design and tolerancing of components for magneto optical (M-O) data storage heads are investigated.

  10. 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

  11. Optical study of a spectrum splitting solar concentrator based on a combination of a diffraction grating and a Fresnel lens

    Energy Technology Data Exchange (ETDEWEB)

    Michel, Céline, E-mail: cmichel@ulg.ac.be; Habraken, Serge [Centre Spatial de Liège, Avenue du Pré-Aily, 4031 Angleur (Belgium); Hololab, University of Liège, Allée du 6 Août, 17 (B5a), 4000 Liège (Belgium); Loicq, Jérôme; Thibert, Tanguy [Centre Spatial de Liège, Avenue du Pré-Aily, 4031 Angleur (Belgium)

    2015-09-28

    This paper presents recent improvements of our new solar concentrator design for space application. The concentrator is based on a combination of a diffraction grating (blazed or lamellar) coupled with a Fresnel lens. Thanks to this diffractive/refractive combination, this optical element splits spatially and spectrally the light and focus approximately respectively visible light and IR light onto electrically independent specific cells. It avoid the use of MJs cells and then also their limitations like current matching and lattice matching conditions, leading theoretically to a more tolerant system. The concept is reminded, with recent optimizations, ideal and more realistic results, and the description of an experimental realization highlighting the feasibility of the concept and the closeness of theoretical and experimental results.

  12. 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....... A study of the effect on transmission of different combinations of available transmission and reflection diffraction orders show optimum total transmission when only the fundamental reflection order and higher transmission diffraction orders are available. The optimum taper angle is shown...

  13. 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

  14. A simple external resistance heating diamond anvil cell and its application for synchrotron radiation x-ray diffraction.

    Science.gov (United States)

    Fan, Dawei; Zhou, Wenge; Wei, Shuyi; Liu, Yonggang; Ma, Maining; Xie, Hongsen

    2010-05-01

    A simple external heating assemblage allowing diamond anvil cell experiments at pressures up to 34 GPa and temperatures up to 653 K was constructed. This cell can be connected to the synchrotron radiation conveniently. The design and construction of this cell are fully described, as well as its applications for x-ray diffraction. Heating is carried out by using an external-heating system, which is made of NiCr resistance wire, and the temperature was measured by a NiCr-NiSi or PtRh-Pt thermocouple. We showed the performance of the new system by introducing the phase transition study of cinnabar (alpha-HgS) and thermal equation of state study of almandine at high pressure and temperature with this cell.

  15. Implementation of ultrafast X-ray diffraction at the 1W2B wiggler beamline of Beijing Synchrotron Radiation Facility.

    Science.gov (United States)

    Sun, Da Rui; Xu, Guang Lei; Zhang, Bing Bing; Du, Xue Yan; Wang, Hao; Li, Qiu Ju; Zhou, Yang Fan; Li, Zhen Jie; Zhang, Yan; He, Jun; Yue, Jun Hui; Lei, Ge; Tao, Ye

    2016-05-01

    The implementation of a laser pump/X-ray probe scheme for performing picosecond-resolution X-ray diffraction at the 1W2B wiggler beamline at Beijing Synchrotron Radiation Facility is reported. With the hybrid fill pattern in top-up mode, a pixel array X-ray detector was optimized to gate out the signal from the singlet bunch with interval 85 ns from the bunch train. The singlet pulse intensity is ∼2.5 × 10(6) photons pulse(-1) at 10 keV. The laser pulse is synchronized to this singlet bunch at a 1 kHz repetition rate. A polycapillary X-ray lens was used for secondary focusing to obtain a 72 µm (FWHM) X-ray spot. Transient photo-induced strain in BiFeO3 film was observed at a ∼150 ps time resolution for demonstration.

  16. 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...

  17. Modeling electron density distributions from X-ray diffraction to derive optical properties: Constrained wavefunction versus multipole refinement

    Science.gov (United States)

    Hickstein, Daniel D.; Cole, Jacqueline M.; Turner, Michael J.; Jayatilaka, Dylan

    2013-08-01

    The rational design of next-generation optical materials requires an understanding of the connection between molecular structure and the solid-state optical properties of a material. A fundamental challenge is to utilize the accurate structural information provided by X-ray diffraction to explain the properties of a crystal. For years, the multipole refinement has been the workhorse technique for transforming high-resolution X-ray diffraction datasets into the detailed electron density distribution of crystalline material. However, the electron density alone is not sufficient for a reliable calculation of the nonlinear optical properties of a material. Recently, the X-ray constrained wavefunction refinement has emerged as a viable alternative to the multipole refinement, offering several potential advantages, including the calculation of a wide range of physical properties and seeding the refinement process with a physically reasonable starting point. In this study, we apply both the multipole refinement and the X-ray constrained wavefunction technique to four molecules with promising nonlinear optical properties and diverse structural motifs. In general, both techniques obtain comparable figures of merit and generate largely similar electron densities, demonstrating the wide applicability of the X-ray constrained wavefunction method. However, there are some systematic differences between the electron densities generated by each technique. Importantly, we find that the electron density generated using the X-ray constrained wavefunction method is dependent on the exact location of the nuclei. The X-ray constrained wavefunction refinement makes smaller changes to the wavefunction when coordinates from the Hartree-Fock-based Hirshfeld atom refinement are employed rather than coordinates from the multipole refinement, suggesting that coordinates from the Hirshfeld atom refinement allow the X-ray constrained wavefunction method to produce more accurate wavefunctions. We

  18. Artificial Optical Radiation photobiological hazards in arc welding.

    Science.gov (United States)

    Gourzoulidis, G A; Achtipis, A; Topalis, F V; Kazasidis, M E; Pantelis, D; Markoulis, A; Kappas, C; Bourousis, C A

    2016-08-01

    Occupational Health and Safety (OHS) is associated with crucial social, economic, cultural and technical issues. A highly specialized OHS sector deals with the photobiological hazards from artificial optical radiation (AOR), which is divided into visible light, UV and IR emitted during various activities and which is legally covered by European Directive 2006/25/EC. Among the enormous amount of sources emitting AOR, the most important non-coherent ones to consider for health effects to the whole optical range, are arcs created during metal welding. This survey presents the effort to assess the complicated exposure limits of the Directive in the controlled environment of a welding laboratory. Sensors covering the UV and blue light range were set to measure typical welding procedures reproduced in the laboratory. Initial results, apart from apparently justifying the use of Personal Protective Equipment (PPE) due to even subsecond overexposures measured, also set the basis to evaluate PPE's properties and support an integrated risk assessment of the complex welding environment. These results can also improve workers' and employer's information and training about radiation hazards, which is a crucial OHS demand.

  19. Simultaneous measurement of position and color of single fluorescent emitters using diffractive optics

    NARCIS (Netherlands)

    Broeken, J.; Rieger, B.; Stallinga, S.

    2014-01-01

    We propose a method for simultaneously measuring the position and emission color of single fluorescent emitters based on the use of a large pitch diffraction grating in the emission light path. The grating produces satellite spots adjacent to the main spot; the relative distance between the spots is

  20. Improved characterization of small particles in laser diffraction by better optical modeling

    NARCIS (Netherlands)

    Butselaar, V.C.L.; Schouten, L.A.; Verheijen, P.J.T.

    2004-01-01

    Laser Diffraction is widely used for the characterization of particle size distributions of powders. For a lot of materials however, the quantification of small particles (< 2 μm) in relation to the rest of the distribution can be ambiguous. The deconvolution of the scattering pattern is done either

  1. Phase transformations in Ni/Ti multilayers investigated by synchrotron radiation-based x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Cavaleiro, A.J., E-mail: andre.cavaleiro@dem.uc.pt [CEMUC, Department of Mechanical Engineering, University of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra (Portugal); Ramos, A.S. [CEMUC, Department of Mechanical Engineering, University of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra (Portugal); Martins, R.M.S. [CENIMAT/I3N, Department of Materials Science, Faculty of Sciences and Technology, University Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); LATR/IST/CTN – Campus Tecnológico e Nuclear, Estrada Nacional 10 ao km 139.7, 2695-066 Bobadela LRS (Portugal); Fernandes, F.M. Braz [CENIMAT/I3N, Department of Materials Science, Faculty of Sciences and Technology, University Nova de Lisboa, 2829-516 Caparica (Portugal); Morgiel, J. [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Reymonta 25, 30-059 Cracow (Poland); Baehtz, C. [Helmholtz Zentrum Dresden Rossendorf HZDR, Institute of Ion Beam Physics and Materials Research, D-01314 Dresden (Germany); Vieira, M.T. [CEMUC, Department of Mechanical Engineering, University of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra (Portugal)

    2015-10-15

    X-ray diffraction using synchrotron radiation was used for real-time investigation of the phase evolution of Ni/Ti multilayer thin films during annealing. These multilayers were deposited onto Ti–6Al–4V substrates by dc magnetron sputtering from pure Ni and Ti targets. The deposition parameters were adjusted in order to obtain a near equiatomic chemical composition and modulation periods (Λ) below 25 nm. Along the entire thickness of the films, well-defined structures with alternate Ni- and Ti-rich layers are observed, even for Λ = 4 nm. In this case, a halo characteristic of an amorphous structure is obtained, while for Λ of 12 and 25 nm the as-deposited thin films are nanocrystalline being possible to identify the (111) Ni and (002) Ti diffraction peaks. The nanolayered structure vanishes during annealing due to interdiffusion followed by reaction. The reaction between Ni and Ti to produce NiTi in the cubic B2 structure occurs in a short delay of time and within a narrow temperature range. For Λ of 25, 12 and 4 nm, the reaction temperature is close to 320, 350 and 385 °C, respectively. For higher temperatures, in addition to the austenitic phase, the NiTi{sub 2} phase is identified. The diffusion of Ti from the substrate and Ni towards the substrate could favour the precipitation of NiTi{sub 2}. - Highlights: • Alternate Ni- and Ti-rich layers are observed, even for short periods. • Phase evolution was studied using synchrotron radiation XRD during annealing. • Ni and Ti reacted at ∼300–400 °C to form B2–NiTi in a single step. • The higher the period the lower the reaction temperature. • At higher temperatures NiTi{sub 2} was detected due to Ni diffusion towards Ti{sub 6}Al{sub 4}V.

  2. 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.

  3. CCD imaging for optical tomography of gel radiation dosimeters.

    Science.gov (United States)

    Wolodzko, J G; Marsden, C; Appleby, A

    1999-11-01

    Several investigations have been carried out by a number of researchers over the past few years to evaluate the utility of imaging gel dosimeters for the three-dimensional measurement of radiation fields. These have been proposed to be of particular value in mapping radiation dose distributions associated with emerging and complex approaches to cancer treatment such as conformal (CRT), intensity modulated (IMRT), "gamma knife," and pencil beam radiotherapies. Imaging of the gels has been successfully accomplished with clinical MRI units and via laser-based optical scanning. However, neither of these methods is generally accessible to all potential users, limiting the broader study and implementation of this valuable tool. We report here the design, methodology, and results of a preliminary study carried out to evaluate the utility of a new, inexpensive, and simplified approach to tomographic imaging of gel radiation dosimeters. For the purpose of this initial investigation, an array of liquid scintillation vials was prepared, containing a ferrous sulphate xylenol orange (FSX) gelatin formulation. The FSX formulation undergoes a change in optical absorption characteristics following irradiation, and the resulting color change can be observed visually. The vials were irradiated individually to different doses. Three-dimensional imaging was accomplished by tomographic reconstruction from two-dimensional optical images acquired using a diffuse, fluorescent light source, a digital charge-coupled device camera, single-photon-emission-computed tomography software, and other simple components designed by the authors. The resulting transverse images were evaluated through a region-of-interest (ROI) analysis to obtain the average change in image density in each vial as a function of radiation dose. These measured ROI values were subjected to a linear regression analysis to fit them to a straight line, and to determine the goodness of fit. Results from multiple imaging trials

  4. 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.

  5. Modeling spatially localized photonic nanojets from phase diffraction gratings

    Energy Technology Data Exchange (ETDEWEB)

    Geints, Yu. E., E-mail: ygeints@iao.ru [V.E. Zuev Institute of Atmospheric Optics SB RAS (IAO SB RAS), 1, Academician Zuev Square, Tomsk 634055 (Russian Federation); Tomsk State University, 36, Lenina Avenue, Tomsk 634050 (Russian Federation); Zemlyanov, A. A. [V.E. Zuev Institute of Atmospheric Optics SB RAS (IAO SB RAS), 1, Academician Zuev Square, Tomsk 634055 (Russian Federation)

    2016-04-21

    We investigated numerically the specific spatially localized intense optical structure, a photonic nanojet (PNJ), formed in the near-field scattering of optical radiation at phase diffraction gratings. The finite-difference time-domain technique was employed to study the PNJ key parameters (length, width, focal distance, and intensity) produced by diffraction gratings with the saw-tooth, rectangle, and hemispheric line profiles. Our analysis showed that each type of diffraction gratings produces a photonic jet with unique characteristics. Based on the numerical calculations, we demonstrate that the PNJ could be manipulated in a wide range through the variation of period, duty cycle, and shape of diffraction grating rulings.

  6. A positron annihilation radiation telescope using Laue diffraction in a crystal lens

    Energy Technology Data Exchange (ETDEWEB)

    Smither, R.K. (Argonne National Lab., IL (United States)); von Ballmoos, P. (Toulouse-3 Univ., 31 (France). Centre d' Etude Spatiale des Rayonnements)

    1993-03-01

    We present a new type of gamma-ray telescope featuring a Laue diffraction lens, a detector module with a 3-by-3 germanium array, and a balloon gondola stabilized to 5 arc sec pointing accuracy. The instrument's lens is designed to collect 511 keV photons on its 150 CM[sup 2] effective area and focus them onto a small detector having only [approx]14 CM[sup 3] of equivalent volume for background noise. As a result, this telescope overcomes the mass-sensitivity impasse of present detectors in which the collection areas are identical to the detection area. The sensitivity of our instrument is anticipated to be 3 [times] 10[sup [minus]5] ph cm[sup [minus]2] S[sup [minus]1] at 511 key with an angular resolution of 15 arc sec and an energy resolution of 2 keV. These features will allow the resolve of a possible energetically narrow 511 keV positron annihilation line both energy-wise and spatially within a Galactic Center microquasar'' as 1El740.7-2942 or GRS1758-258. In addition to the galactic microquasars,'' other prime objectives include Cyg X-1, X-ray binaries, pulsars, and AGNS.

  7. A positron annihilation radiation telescope using Laue diffraction in a crystal lens

    Energy Technology Data Exchange (ETDEWEB)

    Smither, R.K. [Argonne National Lab., IL (United States); von Ballmoos, P. [Toulouse-3 Univ., 31 (France). Centre d`Etude Spatiale des Rayonnements

    1993-03-01

    We present a new type of gamma-ray telescope featuring a Laue diffraction lens, a detector module with a 3-by-3 germanium array, and a balloon gondola stabilized to 5 arc sec pointing accuracy. The instrument`s lens is designed to collect 511 keV photons on its 150 CM{sup 2} effective area and focus them onto a small detector having only {approx}14 CM{sup 3} of equivalent volume for background noise. As a result, this telescope overcomes the mass-sensitivity impasse of present detectors in which the collection areas are identical to the detection area. The sensitivity of our instrument is anticipated to be 3 {times} 10{sup {minus}5} ph cm{sup {minus}2} S{sup {minus}1} at 511 key with an angular resolution of 15 arc sec and an energy resolution of 2 keV. These features will allow the resolve of a possible energetically narrow 511 keV positron annihilation line both energy-wise and spatially within a Galactic Center ``microquasar`` as 1El740.7-2942 or GRS1758-258. In addition to the galactic ``microquasars,`` other prime objectives include Cyg X-1, X-ray binaries, pulsars, and AGNS.

  8. Optical radiation measurements for photovoltaic applications: instrumentation uncertainty and performance

    Science.gov (United States)

    Myers, Daryl R.; Reda, Ibrahim; Wilcox, Stephen; Andreas, Afshin

    2004-11-01

    Evaluating the performance of photovoltaic (PV) devices in the laboratory and in the field requires accurate knowledge of the optical radiation stimulating the devices. We briefly describe the radiometric instrumentation used for characterizing broadband and spectral irradiance for PV applications. Spectral radiometric measurement systems are used to characterize solar simulators (continuous and pulsed, or flash sources) and natural sunlight. Broadband radiometers (pyranometers and pyrheliometers) are used to assess solar resources for renewable applications and develop and validate broadband solar radiation models for estimating system performance. We describe the sources and magnitudes of uncertainty associated with calibrations and measuremens using these instruments. The basic calibration and measurement uncertainty associated with this instrumentaion are based on the guidlines described in the International Standards Organization (ISO) and Bureau INternationale des Poids et Mesures (BIPM) Guide to Uncertainty in Measurement. The additional contributions to uncertainty arising from the uncertainty in characterization functions and correction schemes are discussed and ilustrated. Finally, empirical comparisons of several solar radiometer instrumentation sets illustrate that the best measurement accuracy for broadband radiation is on the order of 3%, and spectrally dependent uncertainty for spectroradiometer systems range from 4% in the visible to 8% to 10% in the ultraviolet and infrared.

  9. 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)

  10. Cancellation of coherent synchrotron radiation kicks with optics balance.

    Science.gov (United States)

    Di Mitri, S; Cornacchia, M; Spampinati, S

    2013-01-04

    Minimizing transverse emittance is essential in linear accelerators designed to deliver very high brightness electron beams. Emission of coherent synchrotron radiation (CSR), as a contributing factor to emittance degradation, is an important phenomenon to this respect. A manner in which to cancel this perturbation by imposing certain symmetric conditions on the electron transport system has been suggested.We first expand on this idea by quantitatively relating the beam Courant-Snyder parameters to the emittance growth and by providing a general scheme of CSR suppression with asymmetric optics, provided it is properly balanced along the line. We present the first experimental evidence of this cancellation with the resultant optics balance of multiple CSR kicks: the transverse emittance of a 500 pC, sub-picosecond, high brightness electron beam is being preserved after the passage through the achromatic transfer line of the FERMI@Elettra free electron laser, and emittance growth is observed when the optics balance is intentionally broken. We finally show the agreement between the theoretical model and the experimental results. This study holds the promise of compact dispersive lines with relatively large bending angles, thus reducing costs for future electron facilities.

  11. 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...... of the MLA structure with a coherent light source. This method is based on a priori knowledge of the grating period. We here present a method that fully characterizes the geometrical properties, i.e. the grating period and the average radius of curvature of an MLA structure in a single measurement cycle....... 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...

  12. Measurements of charge diffusion in deep-depletion CCDs by optical diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Cease, H.; Diehl, H.T.; Estrada, J.; Flaugher, B.; Scarpine, V.; /Fermilab

    2007-10-01

    The charge diffusion is measured in back illuminated, fully depleted, 250 {micro}m thick CCDs by imaging the diffraction pattern of a double slit. The CCDs studied are the focal plane detectors for the Dark Energy Camera (DECam) instrument currently under construction for the Dark Energy Survey (DES). The results presented here indicate that the dispersion of charge due to diffusion can be kept below the DES specification ({sigma}{sub d} < 7.0 {micro}m).

  13. A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-Ping; CHEN Zhao-Yang; BA Wei-Zhen; FAN Yan-Wei; DU Yan-Zhao; PAN Shi-Lie; 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-acoess 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.

  14. 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…

  15. 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…

  16. Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S. K.; McCloy, John S.; Riley, Brian J.; Murphy, Mark K.; Qiao, Hong (Amy); Windisch, Charles F.; Walter, Eric D.; Crum, Jarrod V.; Golovchak, Roman; Shpotyuk, O.

    2012-03-01

    Gamma radiation induces changes in physical, optical, and structural properties in chalcogenide glasses., Previous research has focused on As{sub 2}S{sub 3} and families of glasses containing Ge. For the first time, we present composition and dose dependent data on the As-S binary glass series. Binary As{sub x}S{sub 100-x} (x = 30, 33, 36, 40, and 42) glasses were irradiated with gamma radiation using a {sup 60}Co source at 2.8 Gy/s to accumulated doses of 1, 2, 3, and 4 MGy. The irradiated samples were characterized at each dose level for density, refractive index, x-ray diffraction, and Raman spectrum. These results are compared to those of as-made and 1 year aged samples. We report an initial increase in density followed by a decrease as a function of dose that contradicts the expected compositional dependence of molar volume of these glasses. This unusual behavior is explained based on microvoid formation and nanoscale phase-separation induced by the irradiation in these glasses. XRD, Raman, and EPR data provide supporting evidence, underscoring the importance of optimally- or overly-constrained structures for stability under aging or irradiation.

  17. Temperature dependence of radiation-induced attenuation of optical fibers

    Institute of Scientific and Technical Information of China (English)

    Jingming Song; Jianhua Guo; Xueqin Wang; Jing Jin

    2012-01-01

    We investigate the temperature dependence of radiation-induced attenuation (RIA) at 1 310 nm for a Ge/P co-doped fiber after a steady-state γ-ray irradiation.A γ irradiation facility 60Co source is used to irradiate the fiber at a dose rate of 0.5 Gy/min,satisfying a total dose of 100 Gy.The test temperature ranges from-40 to 60 ℃ by 20 ℃,and the RIA of the fiber is obtained using a power measuring device.The experimental result demonstrates that RIA exhibits a steady,monotonic,and remarkable temperature dependence after approximately 48 h of accelerated annealing at 70 ℃.The optical fiber irradiated with a high dose and annealed sufficiently can be used as a temperature sensor.

  18. Radiation Pressure Force from Optical Cycling on a Polyatomic Molecule

    CERN Document Server

    Kozyryev, Ivan; Matsuda, Kyle; Hemmerling, Boerge; Doyle, John M

    2016-01-01

    We demonstrate multiple photon cycling and radiative force deflection on the triatomic free radical strontium monohydroxide (SrOH). Optical cycling is achieved on SrOH in a cryogenic buffer-gas beam by employing the rotationally closed $P\\left(N''=1\\right)$ branch of the vibronic transition $\\tilde{X}^{2}\\Sigma^{+}\\left(000\\right)\\leftrightarrow\\tilde{A}^{2}\\Pi_{1/2}\\left(000\\right)$. A single repumping laser excites the Sr-O stretching vibrational mode, and photon cycling of the molecule deflects the SrOH beam by an angle of $0.2^{\\circ}$ via scattering of $\\sim100$ photons per molecule. This approach can be used for direct laser cooling of SrOH and more complex, isoelectronic species.

  19. Compound focusing mirror and X-ray waveguide optics for coherent imaging and nano-diffraction.

    Science.gov (United States)

    Salditt, Tim; Osterhoff, Markus; Krenkel, Martin; Wilke, Robin N; Priebe, Marius; Bartels, Matthias; Kalbfleisch, Sebastian; Sprung, Michael

    2015-07-01

    A compound optical system for coherent focusing and imaging at the nanoscale is reported, realised by high-gain fixed-curvature elliptical mirrors in combination with X-ray waveguide optics or different cleaning apertures. The key optical concepts are illustrated, as implemented at the Göttingen Instrument for Nano-Imaging with X-rays (GINIX), installed at the P10 coherence beamline of the PETRA III storage ring at DESY, Hamburg, and examples for typical applications in biological imaging are given. Characteristic beam configurations with the recently achieved values are also described, meeting the different requirements of the applications, such as spot size, coherence or bandwidth. The emphasis of this work is on the different beam shaping, filtering and characterization methods.

  20. 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.)

  1. Convection and radiation effects in hollow, compound optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, J.I. [Room I-320-D, ETS Ingenieros Industriales, Universidad de Malaga, Plaza El Ejido, s/n, 29013 Malaga (Spain)

    2005-09-01

    A coupled model for the study of hollow, compound optical fiber drawing processes that accounts for the heat transfer in the preform and fiber and for the motion of the gases surrounding the preform and fiber by means of two-dimensional equations, employs a net radiative model for the radiative heat exchanges amongst the preform, fiber, irises and furnace walls, and uses asymptotic one-dimensional equations for the geometry, axial velocity component and temperature along the fiber for small Biot numbers is presented. It is shown that the coupled model predicts that radiative heat exchanges are about three times larger than forced convection effects, and free convection is not important. It is also shown that the fiber's geometry, axial velocity and temperature predicted by the coupled model are in remarkable good agreement with those obtained with only the one-dimensional model for hollow, compound fibers using a properly chosen constant Biot number. The results of the one-dimensional model for hollow, compound fibers show that, as the heat transfer losses from the fiber increase, the fiber's dynamic viscosity increases, the fiber exhibits a strong necking phenomenon and the fiber's axial velocity increases rapidly from its value at the die's exit to a constant value downstream and then remains constant. For the boundary conditions considered in this paper, it is shown that the activation energies of the viscosity laws for the inner and outer materials of the hollow, compound fiber do not have very strong effects on the fiber's geometry, axial velocity component and temperature, whereas the fiber's solidification point moves towards the die as the thermal Peclet number is decreased. It is also shown that the pre-exponential factor and activation energy of the dynamic viscosity law do not play a key role in determining the fiber's geometry and temperature for the conditions analyzed in this paper. (authors)

  2. Ultraviolet radiation and bio-optics in Crater Lake, Oregon

    Science.gov (United States)

    Hargreaves, B.R.; Girdner, S.F.; Buktenica, M.W.; Collier, R.W.; Urbach, E.; Larson, G.L.

    2007-01-01

    Crater Lake, Oregon, is a mid-latitude caldera lake famous for its depth (594 m) and blue color. Recent underwater spectral measurements of solar radiation (300-800 nm) support earlier observations of unusual transparency and extend these to UV-B wavelengths. New data suggest that penetration of solar UVR into Crater Lake has a significant ecological impact. Evidence includes a correlation between water column chlorophyll-a and stratospheric ozone since 1984, the scarcity of organisms in the upper water column, and apparent UV screening pigments in phytoplankton that vary with depth. The lowest UV-B diffuse attenuation coefficients (K d,320) were similar to those reported for the clearest natural waters elsewhere, and were lower than estimates for pure water published in 1981. Optical proxies for UVR attenuation were correlated with chlorophyll-a concentration (0-30 m) during typical dry summer months from 1984 to 2002. Using all proxies and measurements of UV transparency, decadal and longer cycles were apparent but no long-term trend since the first optical measurement in 1896. ?? 2007 Springer Science+Business Media B.V.

  3. 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...

  4. 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

    the delicate optical surfaces are buried/sealed in the metal sandwich. The aluminium is then dissolved in warm sodium hydroxide and the glass components are carefully removed. Finally, glue residue is dissolved and the thin gold layer selectively etched. The finished tool insert is then placed in the injection...

  5. Optical dipole mirror for cold atoms based on a metallic diffraction grating

    DEFF Research Database (Denmark)

    Kawalec, Tomasz; Bartoszek-Bober, Dobroslawa; Panas, Roman

    2014-01-01

    and numerically determined mirror efficiencies are close to 100%. The intensity of SPPs above a real grating coupler and the atomic trajectories, as well as the momentum dispersion of the atom cloud being reflected, are computed. A suggestion is given as to how the plasmonic mirror might serve as an optical atom...

  6. 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

    the delicate optical surfaces are buried/sealed in the metal sandwich. The aluminium is then dissolved in warm sodium hydroxide and the glass components are carefully removed. Finally, glue residue is dissolved and the thin gold layer selectively etched. The finished tool insert is then placed in the injection...

  7. Diffusion tensor imaging detects rarefaction of optic radiation in glaucoma patients.

    Science.gov (United States)

    Engelhorn, Tobias; Michelson, Georg; Waerntges, Simone; Struffert, Tobias; Haider, Sultan; Doerfler, Arnd

    2011-06-01

    Diffusion tensor imaging (DTI) can depict rarefaction of the optical fibres. Hence, we applied DTI to assess pathological changes of the optic radiation in glaucoma patients. Fifty glaucoma patients and 50 healthy age-matched controls were examined by a 3T high-field magnetic resonance scanner. Fiber tracts were volume rendered using a semiquantitative approach to assess rarefaction and results were correlated with the extent of optic nerve atrophy and reduced spatial-temporal contrast sensitivity of the retina using established ophthalmological examinations. Twenty-two glaucoma patients (44%) showed significant rarefaction of the optic radiation: the volume was reduced to 67 ± 16% compared with controls. Hereby, the glaucomatous optic nerve atrophy stage correlated with the presence of DTI-derived rarefied optic radiation (Kendall tau-b 0.272, P = .016). Aside, cerebral microangiopathy affecting the optic radiation was significantly higher among glaucoma patients compared to controls (10 patients compared with 2 patients, P < .05). In patients with glaucomatous optic nerve atrophy, there is anterograde and-most likely because of microangiopathic lesions within the optic radiation-retrograde transneuronal rarefaction of the optic radiation that can be assessed in vivo using DTI with good correlation to established ophthalmological examinations. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  8. Table of interplanar spacings for crystal-structure determinations by X-ray diffraction with molybdenum, copper, cobalt, iron, and chromium radiations

    Science.gov (United States)

    Kittel, J Howard

    1945-01-01

    For a simple diffraction pattern, the time required to calculate interplanar distances from measurements of the pattern is not excessive. If more than a few lines are present, however, or if several patterns are to be studied, it is very advantageous to have available a table giving interplanar spacings directly in terms of the linear measurements made on the film of the lines appearing on the diffraction pattern. The preparation of the table given here was undertaken when the expansion of research activities involving X-ray diffraction techniques indicated that such a table would greatly decrease the time required to analyze diffraction patterns. The table was prepared for use with K alpha(sub 1) radiation from the following target materials: molybdenum, copper, cobalt, iron, and chromium.

  9. Experimental modules covering imaging, diffraction, Fourier optics and polarization based on a liquid-crystal cell SLM

    Science.gov (United States)

    Hermerschmidt, Andreas

    2009-06-01

    In close collaboration with four German universities, we have developed tutorials for experiments based on a transmissive liquid-crystal spatial light modulator (SLM). The experimental tutorials are grouped in six project modules, which cover a wide range of phenomena and have different levels of difficulty. At a basic level, students can investigate the SLM in its probably most well-known application as an image-generating element in a simple optical projector setup. At more advanced levels, the application as an adaptive optical element can be investigated in three different projects covering wave-optical phenomena. The fields covered include Fourier Optics using the SLM as a dynamic fan-out beam-splitter or kinoform, Computer-Generated Holography and basic Interferometry. For the support of these projects, software was developed which permits the generation of adaptive optical structures by the student with a user-friendly interface, while the underlying algorithms are explained in the theoretical tutorial. The modulation of the light by the twisted-neumatic liquid crystal cells of the SLM can be investigated in the two most advanced projects. In the first one, the parameters of the cell and the components of its Jones matrix can be derived from transmission measurements with rotatable polarizers at a number of different wavelengths. This project gives insight to the Jones matrix calculus at the level required for the analysis. In the second one, the complex-valued transmission of the SLM is determined by measuring the diffraction efficiency of dynamically addressed Ronchi gratings.

  10. 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.

  11. Engineering of high purity ultra-long optical needle field through reversing the electric dipole array radiation.

    Science.gov (United States)

    Wang, Jiming; Chen, Weibin; Zhan, Qiwen

    2010-10-11

    We report a new method to create high purity longitudinally polarized field with extremely long depth of focus in the focal volume of a high numerical aperture (NA) objective lens. Through reversing the radiated field from an electric dipole array situated near the focus of the high-NA lens, the required incident field distribution in the pupil plane for the creation of an ultra-long optical needle field can be found. Numerical examples demonstrate that an optical needle field with a depth of focus up to 8λ is obtainable. Throughout the depth of focus, this engineered focal field maintains a diffraction limited transverse spot size (<0.43λ) with high longitudinal polarization purity. From the calculated pupil plane distribution, a simplified discrete complex pupil filter can be designed and significant improvements over the previously reported complex filters are clearly demonstrated.

  12. 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.

  13. 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

    of the MLA structure with a coherent light source. This method is based on a priori knowledge of the grating period. We here present a method that fully characterizes the geometrical properties, i.e. the grating period and the average radius of curvature of an MLA structure in a single measurement cycle....... 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...... present experimental data extracted from two different MLA structures using the proposed method. The results are compared with atomic force microscopy measurements of the MLA geometry....

  14. Lack of radiation optic neuropathy in 72 patients treated for pituitary adenoma

    NARCIS (Netherlands)

    van den Bergh, ACM; Dullaart, RPF; van der Vliet, AM; Szabo, BG; ter Weeme, CA; Pott, JWR

    The incidence of radiation optic neuropathy (RON) after external photon beam radiation therapy for nonfunctioning pituitary adenoma (NFA) is not well-studied. Retrospective review of ophthalmological and imaging data in 72 patients with NFA treated between 1985 and 1998 with external beam radiation

  15. Calibrated, multiband radiometric measurements of the optical radiation from lightning

    Science.gov (United States)

    Quick, Mason G.

    Calibrated, multiband radiometric measurements of the optical radiation emitted by rocket-triggered lightning (RTL) have been made in the ultraviolet (UV, 200-360 nm), the visible and near infrared (VNIR, 400-1000 nm), and the long wave infrared (LWIR, 8-12 microm) spectral bands. Measurements were recorded from a distance of 198 m at the University of Florida International Center for Lightning Research and Testing (ICLRT) during the summers of 2011 and 2012. The ICLRT provided time-correlated measurements of the current at the base of the RTL channels. Following the onset of a return stroke, the dominant mechanism for the initial rise of the UV and VNIR waveforms was the geometrical growth of the channel in the field-of-view of the sensors. The UV emissions peaked about 0.7 micros after the current peak, with a peak spectral power emitted by the source per unit length of channel of 10 +/- 7 kW/(nm-m) in the UV. The VNIR emissions peaked 0.9 micros after the current peak, with a spectral power of at 7 +/- 4 kW/(nm-m). The LWIR emissions peaked 30-50 micros after the current peak, and the mean peak spectral power was 940 +/- 380 mW/(nm-m), a value that is about 4 orders of magnitude lower than the other spectral band emissions. In some returns strokes the LWIR peak coincides with a secondary maximum in the VNIR band that occurs during a steady decrease in channel current. Examples of the optical waveforms in each spectral band are shown as a function of time and are discussed in the context of the current measured at the channel base. Source power estimates in the VNIR band have a mean and standard deviation of 2.5 +/- 2.2 MW/m and are in excellent agreement with similar estimates of the emission from natural subsequent strokes that remain in a pre-existing channel which have a mean and standard deviation of 2.3 +/- 3.4 MW/m. The peak optical power emitted by RTL in the UV and VNIR bands are observed to be proportional to the square of the peak current at the

  16. Laser Setup for Volume Diffractive Optical Elements Recording in Photo-Thermo-Refractive Glass

    Science.gov (United States)

    2016-04-14

    ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 UV laser , third harmonic generation, hologram recording...of uniformity of VBGs across the aperture that is a key for large aperture pulse compressors used in high power ultrashort pulse lasers . ? A new...the College of Optics and Photonics, University of Central Florida. 4304 Scorpius Str. Orlando, FL 32816 6. Key words: UV laser , third harmonic

  17. Single-Slit Diffraction: Transitioning from Geometric Optics to the Fraunhofer Regime

    Science.gov (United States)

    Panuski, Christopher L.; Mungan, Carl E.

    2016-01-01

    Suppose a red laser beam (of wavelength ? equal to 0.660 µm) is expanded using an optical telescope into a collimated, approximately plane wave that is 5.68 mm in diameter. Pass that beam through a tall rectangular slit whose width "a" is gradually reduced from 3.30 to 0.100 mm. Look at its image on a screen located at a distance…

  18. X-Ray Polarization Optics and Coherent Nuclear Resonance Scattering Using Synchrotron Radiation.

    Science.gov (United States)

    Shastri, Sarvjit Devdat

    1995-01-01

    Two projects, both involving X-ray scattering with synchrotron radiation, are presented in this dissertation. (1) A system of diffracting perfect crystals for the generation of variable, elliptically polarized X-rays was tested at the Cornell High Energy Synchrotron Source under the conditions of a standard undulator source. The phase retarding optical component was a 4-bounce, Ge(220) Bragg reflection channel -cut crystal. The full polarization state (density matrix) of the output beam, including the circular polarization purity P_3, was determined using the multiple-beam Bragg diffraction technique with a GaAs crystal polarimeter and was found to agree with calculations. In addition to measuring the optics' efficiency, the ability to scan the system in energy, while frequently reversing the circular helicity, was demonstrated at the vicinity of the Fe K-edge at 7.1 keV. The setup was applied to a circular magnetic X-ray dichroism measurement. (2) The time distribution of delayed photons from resonant forward scattering of 14.4 keV synchrotron radiation pulses by ^{57}Fe nuclei was investigated over the temperature range from 9 K to just above the Curie point at 1043 K, with particular attention to precise measurements of the Lamb-Mossbauer factor f_{LM } ~ e^{- } , whose change was determined from its influence on the "speed-up" of coherent decay. Apart from its importance in Mossbauer effect studies, knowing the temperature dependence of f_{LM} can be valuable for studies of lattice dynamics and structural phase transitions. The change in the nuclear hyperfine splitting was also measured. The synchrotron technique has precision-enhancing advantages over conventional Mossbauer spectroscopy methods employing radioactive sources because dealing with source effects and absolute intensity measurements is eliminated. The results also straightforwardly illustrate an interesting principle concerning the temperature dependence of scattering --that for "slow" resonance

  19. Application of the method of auxiliary sources to a defect-detection inverse problem of optical diffraction microscopy

    DEFF Research Database (Denmark)

    Karamehmedovic, Mirza; Sørensen, Mads Peter; Hansen, Poul Erik

    2010-01-01

    We propose a method of numerical solution of a type of inverse scattering problem that arises in the optical characterisation/quality control of nanostructures. The underlying global, ill-posed, nonlinear optimisation problem is first localised by best-fit matching of library and measured...... the proposed method, we apply it in a concrete quantitative characterisation of a non-periodic, nano-scale grating defect, with numerically simulated measurements. It is shown that the presented procedure can solve the inverse problem with an accuracy usually thought to require rigorous electromagnetic...... diffraction efficiency patterns. The inverse problem is then solved using piecewise linear interpolation between the best far-field matches. Finally, the results are refined, on average, by solving an additional local optimisation problem formulated in terms of the method of auxiliary sources. To illustrate...

  20. Exoplanet Imaging with a Phase-induced Amplitude Apodization Coronagraph III. Hybrid Approach: Optical Design and Diffraction Analysis

    CERN Document Server

    Pluzhnik, E A; Galicher, R; Guyon, O; Martinache, F; Ridgway, S T; Woodruff, R A

    2005-01-01

    Properly apodized pupils can deliver point spread functions (PSFs) free of Airy rings, and are suitable for high dynamical range imaging of extrasolar terrestrial planets (ETPs). To reach this goal, classical pupil apodization (CPA) unfortunately requires most of the light gathered by the telescope to be absorbed, resulting in poor throughput and low angular resolution. Phase-induced amplitude apodization (PIAA) of the telescope pupil (Guyon 2003) combines the advantages of classical pupil apodization (particularly low sensitivity to low order aberrations) with full throughput, no loss of angular resolution and little chromaticity, which makes it, theoretically, an extremely attractive coronagraph for direct imaging of ETPs. The two most challenging aspects of this technique are (1) the difficulty to polish the required optics shapes and (2) diffraction propagation effects which, because of their chromaticity, can decrease the spectral bandwidth of the coronagraph. We show that a properly designed hybrid syst...

  1. 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.

  2. Design of the mirror optical systems for coherent diffractive imaging at the SPB/SFX instrument of the European XFEL

    Science.gov (United States)

    Bean, Richard J.; Aquila, Andrew; Samoylova, Liubov; Mancuso, Adrian P.

    2016-07-01

    The high degree of spatial coherence and extreme pulse energies available at x-ray free electron laser (XFEL) sources naturally support coherent diffractive imaging applications. In order to optimally exploit these unique properties, the optical systems at XFELs must be highly transmissive, focus to appropriate sizes matched to the scale of samples to be investigated and must minimally perturb the wavefront of the XFEL beam. We present the design and simulated performance of two state-of-the-art Kirkpatrik-Baez mirror systems that form the primary foci of the single particles, clusters and biomolecules and serial femtosecond crystallography (SPB/SFX) instrument of the European XFEL. The two systems, presently under construction, will produce 1 μm and 100 nm scale foci across a 3-16 keV photon energy range. Targeted applications include coherent imaging of weakly scattering, often biological, specimens.

  3. 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...

  4. Optical diffraction tomography using a digital micromirror device for stable measurements of 4D refractive index tomography of cells

    Science.gov (United States)

    Shin, Seungwoo; Kim, Kyoohyun; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-03-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information about the values and gradient of RI tomograms.

  5. 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.

  6. Optical diffraction tomography using a digital micromirror device for stable measurements of 4-D refractive index tomography of cells

    CERN Document Server

    Shin, Seungwoo; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-01-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information abou...

  7. Performance evaluation of a radial in-plane digital speckle pattern interferometer using a diffractive optical element for residual stress measurement

    Science.gov (United States)

    Albertazzi, A., Jr.; Viotti, M. R.; Kapp, W. A.

    2010-08-01

    A digital speckle pattern (DSP) interferometer using a special diffractive optical element (DOE) was developed by the authors. A collimated laser beam is diffracted by the DOE in such a way that the first diffraction orders produce a circular double illuminated measurement area. Due to natural symmetry of the illumination scheme, the interferometer reaches pure radial in-plane sensitivity. It is demonstrated and verified that the resulting interferometer is not sensitive to laser wavelength variations at all. Its configuration is presented as well as its performance evaluation for residual stress measurements using the blind hole-drilling method.

  8. 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.

  9. Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

    Science.gov (United States)

    Rofouie, P.; Pasini, D.; Rey, A. D.

    2015-09-01

    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.

  10. Measurements of longitudinal gamma ray distribution using a multichannel fiber-optic Cerenkov radiation sensor

    Science.gov (United States)

    Shin, S. H.; Jeon, D.; Kim, J. S.; Jang, J. S.; Jang, K. W.; Yoo, W. J.; Moon, J. H.; Park, B. G.; Kim, S.; Lee, B.

    2014-11-01

    Cerenkov radiation occurs when charged particles are moving faster than the speed of light in a transparent dielectric medium. In optical fibers, Cerenkov radiation can also be generated due to the fiber’s dielectric components. Accordingly, the radiation-induced light signals can be obtained using the optical fibers without any scintillating material. In this study, we fabricated a multichannel, fiber-optic Cerenkov radiation sensor (FOCRS) system using silica optical fibers (SOFs), plastic optical fibers (POFs), an optical spectrometer, multi-anode photomultiplier tubes (MA-PMTs) and a scanning system to measure the light intensities of Cerenkov radiation induced by gamma rays. To evaluate the fading effects in optical fibers, the spectra of Cerenkov radiation generated in the SOFs and POFs were measured based on the irradiation time by using an optical spectrometer. In addition, we measured the longitudinal distribution of gamma rays emitted from the cylindrical type Co-60 source by using MA-PMTs. The result was also compared with the distribution of the electron flux calculated by using the Monte Carlo N-particle transport code (MCNPX).

  11. Simulation of emission and propagation of coherent synchrotron radiation wave fronts using the methods of wave optics

    Science.gov (United States)

    Chubar, O.

    2006-09-01

    The paper describes methods of efficient calculation of spontaneous synchrotron radiation (SR) by relativistic electrons in storage rings, and propagation of this radiation through optical elements and drift spaces of beamlines, using the principles of wave optics. In addition to the SR from one electron, incoherent and coherent synchrotron radiation (CSR) emitted by electron bunches is treated. CPU-efficient CSR calculation method taking into account 6D phase space distribution of electrons in a bunch is proposed. The properties of CSR emitted by electron bunches with small longitudinal and large transverse size are studied numerically (such situation can be realized in storage rings e.g. by transverse deflection of the electron bunches in special RF cavities). It is shown that if the transverse size of a bunch is much larger than the diffraction limit for single-electron SR at a given wavelength - it affects the angular distribution of the CSR at this wavelength and reduces the coherent flux. Nevertheless, for transverse bunch dimensions up to several millimeters and the longitudinal bunch size smaller than hundred micrometers, the resulting CSR flux in the far infrared spectral range is still many orders of magnitude higher than the flux of incoherent SR.

  12. 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.

  13. 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. [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); Wiese, A.; Ziolkowski, M. [Fachbereich Physik, Universität Siegen, Siegen (Germany)

    2013-12-11

    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 Vertical Cavity Surface Emitting Laser (VCSEL) 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. We have tested the ASIC and the performance 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. Preliminary results of the design will be presented.

  14. 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. [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); Wiese, A.; Ziolkowski, M. [Fachbereich Physik, Universität Siegen, Siegen (Germany)

    2014-11-21

    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.

  15. War Induced Aerosol Optical, Microphysical and Radiative Effects

    Science.gov (United States)

    Munshi, Pavel; Tiwari, Shubhansh

    2017-01-01

    The effect of war on air pollution and climate is assessed in this communication. War today in respect of civil wars and armed conflict in the Middle East area is taken into consideration. Impacts of war are not only in loss of human life and property, but also in the environment. It is well known that war effects air pollution and in the long run contribute to anthropogenic climate change, but general studies on this subject are few because of the difficulties of observations involved. In the current scenario of the ongoing conflict in the Middle East regions, deductions in parameters of atmosphere are discussed. Aerosol Optical Depth, Aerosol loads, Black Carbon, Ozone,Dust, regional haze and many more are analyzed using various satellite data. Multi-model analysis is also studied to verify the analysis. Type segregation of aerosols, in-depth constraints to atmospheric chemistry, biological effects and particularly atmospheric physics in terms of radiative forcing, etc. are discussed. Undergraduate in Earth Sciences.

  16. AOLI-- Adaptive Optics Lucky Imager: Diffraction Limited Imaging in the Visible on Large Ground-Based Telescopes

    CERN Document Server

    Mackay, Craig; Castellá, Bruno Femenia; Crass, Jonathan; King, David L; Labadie, Lucas; Aisher, Peter; Garrido, Antonio Pérez; Balcells, Marc; Díaz-Sánchez, Anastasio; Fuensalida, Jesús Jimenez; Lopez, Roberto L; Oscoz, Alejandro; Prieto, Jorge A Pérez; Rodríguez-Ramos, Luis F; Villó, Isidro

    2012-01-01

    The highest resolution images ever taken in the visible were obtained by combining Lucky Imaging and low order adaptive optics. This paper describes a new instrument to be deployed on the WHT 4.2m and GTC 10.4 m telescopes on La Palma, with particular emphasis on the optical design and the expected system performance. A new design of low order wavefront sensor using photon counting CCD detectors and multi-plane curvature wavefront sensor will allow dramatically fainter reference stars to be used, allowing virtually full sky coverage with a natural guide star. This paper also describes a significant improvements in the efficiency of Lucky Imaging, important advances in wavefront reconstruction with curvature sensors and the results of simulations and sensitivity limits. With a 2 x 2 array of 1024 x 1024 photon counting EMCCDs, AOLI is likely to be the first of the new class of high sensitivity, near diffraction limited imaging systems giving higher resolution in the visible from the ground than hitherto been p...

  17. Achromatic digital speckle pattern interferometer with constant radial in-plane sensitivity by using a diffractive optical element

    Energy Technology Data Exchange (ETDEWEB)

    Viotti, Matias R.; Kapp, Walter; Armando Albertazzi, G. Jr.

    2009-04-20

    We report on a digital speckle pattern interferometer that applies a binary diffractive optical element (DOE) to generate double illumination and radial in-plane sensitivity. The application of the DOE ensures independence on the wavelength of the laser used as an illumination source. Furthermore, in-plane sensitivity only depends on the grating period of the DOE. An experimental setup was built allowing the measurement of a set of radial in-plane displacement fields either using a red laser as a light source or a green one. When displacement fields computed from the measured optical phase maps obtained with a red or a green laser were compared, two main results were observed: (a) deviations between mean values ranged only up to 7 nm and (b) phase maps presented the same amount of fringes. In addition, phase maps measured with the red laser were processed as they were obtained with green light. For this case, deviations have ranged only up to 0.5 nm. On the other hand, a set of measurements performed changing the DOE by a conical mirror showed clearly that radial in-plane sensitivity increased when the red laser was changed by the green one.

  18. Visual and optical performance of diffractive multifocal intraocular lenses with different haptic designs: 6 month follow-up.

    Science.gov (United States)

    Wang, Mengmeng; Corpuz, Christine Carole C; Fujiwara, Megumi; Tomita, Minoru

    2014-01-01

    To evaluate and compare the visual acuity outcomes and optical performances of eyes implanted with two diffractive multifocal intraocular lens (IOL) models with either a plate haptic design or a modified-C design. This retrospective study comprised cataract patients who were implanted with either a plate haptic multifocal IOL model (Acriva(UD) Reviol BB MFM 611 [VSY Biotechnology, Amsterdam, the Netherlands], group 1) or a modified-C haptic multifocal IOL model (Acriva(UD) Reviol BB MF 613 [VSY Biotechnology, Amsterdam, the Netherlands], group 2) between June 2012 and May 2013. The 6 month postoperative visual acuity, refraction, defocus curve, contrast sensitivity, and wave-front aberration were evaluated and compared between these eyes, using different IOL models. One hundred fifty-eight eyes of 107 patients were included in this study. Significant improvement in visual acuities and refraction was found in both groups after cataract surgery (P0.05). However, the ocular higher-order aberrations in group 2 were significantly greater than in group 1 (Phaptic design resulted in better optical performances than that with the modified-C haptic design.

  19. 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.

  20. Engineering of radiation of optically active molecules with chiral nano-meta-particles

    CERN Document Server

    Klimov, Vasily V; Ducloy, Martial

    2011-01-01

    The radiation of optically active (chiral) molecule placed near chiral nanoparticle is investigated. The optimal conditions for engineering of radiation of optically active (chiral) molecules with the help of chiral nanoparticles are derived. It is shown that for this purpose, the substance of the chiral particle must have both \\epsilon_and \\mu_negative (double negative material (DNG)) or negative \\mu_and positive \\epsilon_(\\mu_negative material (MNG)). Our results pave the way to an effective engineering of radiation of "left" and "right" molecules and to creating pure optical devices for separation of drugs enantiomers.

  1. Engineering of radiation of optically active molecules with chiral nano-meta-particles

    Science.gov (United States)

    Klimov, V. V.; Guzatov, D. V.; Ducloy, M.

    2012-02-01

    The radiation of an optically active (chiral) molecule placed near a chiral nanosphere is investigated. The optimal conditions for engineering of radiation of optically active (chiral) molecules with the help of chiral nanoparticles are derived. It is shown that for this purpose, the substance of the chiral particle must have both ɛ and μ negative (double negative material (DNG)) or negative μ and positive ɛ (μ negative material (MNG)). Our results pave the way to an effective engineering of radiation of "left" and "right" molecules and to creating pure optical devices for separation of drugs enantiomers.

  2. 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.

  3. The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

    Energy Technology Data Exchange (ETDEWEB)

    Schäfers, F., E-mail: franz.schaefers@helmholtz-berlin.de; Bischoff, P.; Eggenstein, F.; Erko, A.; Gaupp, A.; Künstner, S.; Mast, M.; Schmidt, J.-S.; Senf, F.; Siewert, F.; Sokolov, A.; Zeschke, Th. [Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse 15, Berlin 12489 (Germany)

    2016-01-01

    A new optics beamline and a versatile 11-axes UHV-reflectometer for at-wavelength characterization of real life-sized UV- and XUV-reflection gratings and other (nano-) optical elements has been set up and is in operation at BESSY-II. Azimuthal rotation of samples allows for reflectometry and polarimetry measurements in s- and p-polarization. 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{sup −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.

  4. Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

    Directory of Open Access Journals (Sweden)

    Shiv Govind Prasad

    2011-01-01

    Full Text Available Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET polymer films have been investigated by X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, and ultraviolet-visible (UV-VIS spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

  5. Modeling of the angular tolerancing of an effective medium diffractive lens using combined finite difference time domain and radiation spectrum method algorithms.

    Science.gov (United States)

    Raulot, Victorien; Gérard, Philippe; Serio, Bruno; Flury, Manuel; Kress, Bernard; Meyrueis, Patrick

    2010-08-16

    A new rigorous vector-based design and analysis approach of diffractive lenses is presented. It combines the use of two methods: the Finite-Difference Time-Domain for the study in the near field, and the Radiation Spectrum Method for the propagation in the far field. This approach is proposed to design and optimize effective medium cylindrical diffractive lenses for high efficiency structured light illumination systems. These lenses are realised with binary subwavelength features that cannot be designed using the standard scalar theory. Furthermore, because of their finite and high frequencies characteristics, such devices prevent the use of coupled wave theory. The proposed approach is presented to determine the angular tolerance in the cases of binary subwavelength cylindrical lenses by calculating the diffraction efficiency as a function of the incidence angle.

  6. Optical diffraction into thick slab waveguides: a finite-beam RCWA approach to solve extremely asymmetrical scattering-EAS in slanted holographic gratings

    Science.gov (United States)

    Pietralunga, Silvia M.; Geroldi, Alessandro; Serafini, Mirko

    2012-06-01

    We have implemented a Finite-Beam Rigorous Coupled-Wave Approach (FB-RCWA) to solve for guided-optics propagation in the presence of holographic slanted Bragg gratings, embedded in the core of slab waveguides and operated in Extreme Asymmetrical Scattering (EAS) configuration. In EAS a resonance condition can be established, as proceeding from the design parameters. Diffraction efficiency can be evaluated as the ratio of the flux of diffracted power P1, on a suitably defined cross-section along the propagation of diffracted beam, and input power P0. By FBRCWA, no limitation in the depth of grating modulation is assumed. The first-order diffracted field in resonant Bragg condition propagates along the waveguide. EAS in thick waveguides operating in highly multimodal regime can be investigated, as well as macroscopic volumes and widely extended illuminated regions up to a few millimeters. In thick slabs, η > 90% is demonstrated, for input illuminated apertures of length L >= Lc, where Lc is the optimum coupling length. The effects of detuning from Bragg condition, both in distribution and amplitude of the diffracted field, are quantified. Diffraction efficiency, i.e. optical coupling, bandwidth is evaluated.

  7. Modeling simulation of the thermal radiation for high-speed flight vehicles' aero-optical windows

    Science.gov (United States)

    Chen, Lei; Zhang, Liqin; Guo, Mingjiang

    2015-10-01

    When high-speed flight vehicles fly in the atmosphere, they can generate serious aero-optical effect. The optical window temperature rises sharply because of aerodynamic heating. It will form radiation interference that can lead infrared detectors to producing non-uniform radiation backgrounds, decreasing system SNR and detection range. Besides, there exits temperature difference due to uneven heating. Under the thermo-optical and elastic-optical effects, optical windows change into inhomogeneous mediums which influence the ray propagation. In this paper, a model of thermal radiation effect was built by a finite element analysis method. Firstly, the optical window was divided into uniform grids. Then, radiation distribution on the focal planes at different angles of the window's normal line and optical axis was obtained by tracing light rays of each grid. Finally, simulation results indicate that radiation distribution reflects the two directions-the length and width-of temperature distribution, and the change of angle causes the center of radiation distribution to shift to one direction of the image surface under the same window temperature.

  8. Effect of gamma radiation on optical and electrical properties of tellurium dioxide thin films

    Indian Academy of Sciences (India)

    T K Maity; S L Sharma

    2008-11-01

    Gamma radiation induced changes in the optical and electrical properties of tellurium dioxide (TeO2) thin films, prepared by thermal evaporation, have been studied in detail. The optical characterization of the as-deposited thin films and that of the thin films exposed to various levels of gamma radiation dose clearly show that the optical bandgap decreases with increase in the gamma radiation dose up to a certain dose. At gamma radiation doses above this value, however, the optical bandgap has been found to increase. On the other hand, the current vs voltage plots for the as-deposited thin films and those for the thin films exposed to various levels of gamma radiation dose show that the current increases with the gamma radiation dose up to a certain dose and that the value of this particular dose depends upon the thickness of the film. The current has, however, been found to decrease with further increase in gamma radiation dose. The observed changes in both the optical and electrical properties indicate that TeO2 thin films can be used as the real time gamma radiation dosimeter up to a certain dose, a quantity that depends upon the thickness of the film.

  9. 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.

  10. Fundamental research on a cerenkov radiation sensor based on optical glass for detecting beta-rays

    Science.gov (United States)

    Kim, Jae Seok; Jang, Kyoung Won; Shin, Sang Hun; Jeon, Dayeong; Hong, Seunghan; Sim, Hyeok In; Kim, Seon Geun; Yoo, Wook Jae; Lee, Bongsoo; Moon, Joo Hyun; Park, Byung Gi

    2015-01-01

    In this study, a Cerenkov radiation sensor for detecting low-energy beta-particles was fabricated using various Cerenkov radiators such as an aerogel and CaF2-, SiO2-, and Al2O3-based optical glasses. Because the Cerenkov threshold energy (CTE) is determined by the refractive index of the Cerenkov radiator, the intensity of Cerenkov radiation varies according to the refractive indices of the Cerenkov radiators. Therefore, we measured the intensities of Cerenkov radiation induced by beta-particles generated from a radioactive isotope as a function of the refractive indices of the Cerenkov radiators. Also, the electron fluxes were calculated for various Cerenkov radiators by using a Monte Carlo N-Particle extended transport code (MCNPX) to determine the relationship between the intensities of the Cerenkov radiation and the electron fluxes.

  11. 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.

  12. 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.

  13. Broadband multilayer mirror and diffractive optics for attosecond pulse shaping in the 280-500 eV photon energy range

    Directory of Open Access Journals (Sweden)

    Schmidt J.

    2013-03-01

    Full Text Available Chirped broadband multilayer mirrors are key components to shape attosecond pulses in the XUV range. Compressing high harmonic pulses to their Fourier limit is the major goal for attosecond physics utilizing short pulse pump-probe experiments. Here, we report about the first implementation of multilayers and diffractive optics fulfilling these requirements in the “water-window” spectral range.

  14. Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

    Science.gov (United States)

    Kawai, Kotaro; Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2016-03-01

    A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.

  15. Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Kotaro, E-mail: s135016@stn.nagaokaut.ac.jp; Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Ono, Hiroshi [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Kawatsuki, Nobuhiro [Department of Applied Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan)

    2016-03-28

    A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.

  16. Elimination of Cerenkov interference in a fibre-optic-coupled radiation dosemeter.

    Science.gov (United States)

    Justus, Brian L; Falkenstein, Paul; Huston, Alan L; Plazas, Maria C; Ning, Holly; Miller, Robert W

    2006-01-01

    An optical fibre point dosemeter based on the gated detection of the luminescence from a Cu(1+)-doped fused quartz detector effectively eliminated errors due to Cerenkov radiation and native fibre fluorescence. The gated optical fibre dosemeter overcomes serious problems faced by scintillation and optically stimulated luminescence approaches to optical fibre point dosimetry. The dosemeter was tested using an external beam radiotherapy machine that provided pulses of 6 MV X rays. Gated detection was used to discriminate the signal collected during the radiation pulses, which included contributions from Cerenkov radiation and native fibre fluorescence, from the signal collected between the radiation pulses, which contained only the long-lived luminescence from the Cu(1+)-doped fused quartz detector. Gated detection of the luminescence provided accurate, real-time dose measurements that were linear with absorbed dose, independent of dose rate and that were accurate for all field sizes studied.

  17. The effect of the earth's radiation belts on an optical system.

    Science.gov (United States)

    Wolff, C

    1966-11-01

    A photoelectric optical imaging system has survived one year in the earth's radiation belts with no measurable (radiation belts twice every 64 hr, and experiences a noise level equivalent to 400 photons/sec when in their most intense regions. While this noise is far less than that of other photoelectric systems operating in the belts because of the small effective area of the photocathode, the noise per unit cathode area is 1.3 x 10(5) photons/sec-cm(2), and is similar to the best of the other systems. The number and energy distribution of incident particles is calculated and then combined with shielding estimates to give the total energy absorbed in the optical elements. Radiation damage reports in the literature are shown to be consistent with the lack of a sensitivity change in this orbiting optical system. The effects of particle radiation on optical systems in general is briefly summarized, with emphasis on recent work of others.

  18. 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.

  19. Radiation Hard Multi-Layer Optical Coatings Project

    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...

  20. Electron transfer in a virtual quantum state of LiBH4 induced by strong optical fields and mapped by femtosecond x-ray diffraction.

    Science.gov (United States)

    Stingl, J; Zamponi, F; Freyer, B; Woerner, M; Elsaesser, T; Borgschulte, A

    2012-10-05

    Transient polarizations connected with a spatial redistribution of electronic charge in a mixed quantum state are induced by optical fields of high amplitude. We determine for the first time the related transient electron density maps, applying femtosecond x-ray powder diffraction as a structure probe. The prototype ionic material LiBH4 driven nonresonantly by an intense sub-40 fs optical pulse displays a large-amplitude fully reversible electron transfer from the BH4(-) anion to the Li+ cation during excitation. Our results establish this mechanism as the source of the strong optical polarization which agrees quantitatively with theoretical estimates.

  1. 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.)

  2. Breaking the diffraction-limited resolution barrier in fiber-optical two-photon fluorescence endoscopy by an azimuthally-polarized beam.

    Science.gov (United States)

    Gu, Min; Kang, Hong; Li, Xiangping

    2014-01-10

    Although fiber-optical two-photon endoscopy has been recognized as a potential high-resolution diagnostic and therapeutic procedure in vivo, its resolution is limited by the optical diffraction nature to a few micrometers due to the low numerical aperture of an endoscopic objective. On the other hand, stimulated emission depletion (STED) achieved by a circularly-polarized vortex beam has been used to break the diffraction-limited resolution barrier in a bulky microscope. It has been a challenge to apply the STED principle to a fiber-optical two-photon endoscope as a circular polarization state cannot be maintained due to the birefringence of a fiber. Here, we demonstrate the first fiber-optical STED two-photon endoscope using an azimuthally-polarized beam directly generated from a double-clad fiber. As such, the diffraction-limited resolution barrier of fiber-optical two-photon endoscopy can be broken by a factor of three. Our new accomplishment has paved a robust way for high-resolution in vivo biomedical studies.

  3. Effects of Polarization-Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

    Institute of Scientific and Technical Information of China (English)

    XIAO Wen; LIU De-Wen; LIU Yang; YI Xiao-Su; CONG Lin

    2008-01-01

    @@ In the space environment, the precision of fibre optic gyroscopes (FOGs) degrades because of space radiation.Photonic components of FOGs axe affected by radiation, especially the polaxization-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 60Co radiation source at different dose rates. Based on the experimental results, the formula between the PM-fibre loss and radiation dose rata 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.

  4. 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

  5. Proton radiation testing of laser optical components for NASA Jupiter Europa Orbiter Mission

    Science.gov (United States)

    Thomes, W. Joe, Jr.; Cavanaugh, John F.; Ott, Melanie N.

    2011-09-01

    The Jupiter Europa Orbiter (JEO) is NASA's element of the joint Europa Jupiter System Mission (EJSM). Based on current trajectories, the spacecraft will spend a significant amount of time in the Jovian radiation belts. Therefore, research endeavors are underway to study the radiation effects on the various parts and components needed to implement the instruments. Data from these studies will be used for component selection and system design to ensure reliable operation throughout the mission duration. The radiation environment en route to Jupiter is nothing new for NASA designed systems, however, the long durations orbiting Jupiter and Europa present new challenges for radiation exposure. High-energy trapped electrons and protons at Jupiter dominate the expected radiation environment. Therefore, most of the initial component level radiation testing is being conducted with proton exposure. In this paper we will present in-situ monitoring of the optical transmission of various laser optical components during proton irradiation. Radiation induced optical attenuation of some components is less than would be expected, based on the authors experiences, and is attributed to the interaction of the protons with the materials. The results are an encouraging first step in screening these optical materials for spaceflight in a high radiation environment.

  6. Diffractive super-resolution elements applied to near-field optical data storage with solid immersion lens

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yaoju [Department of Physics, Wenzhou Normal College, Wenzhou 325027 (China); Xiao Huaceng [Department of Biology, Wenzhou Normal College, Wenzhou 325027 (China); Zheng Chongwei [Department of Physics, Wenzhou Normal College, Wenzhou 325027 (China)

    2004-07-01

    The intensity distribution in near-field optical data storage with a solid immersion lens (SIL) and a binary phase-only diffractive super-resolution element (DSE) is expressed in a single definite integral by using angular spectrum theory. The super-resolution of binary two-zone phase DSEs for SIL systems is numerically studied for low and high numerical aperture (NA) systems. The results for the low-NA systems show that optimizing the zone boundary and phase of binary two-zone phase DSEs can decrease the spot size. The Strehl ratio, sidelobe intensity and axial characteristic length are also discussed. In addition, a binary two-zone phase filter can change the position of focus that shifts from the SIL-air interface to air, but the spot size increases. For the high-NA systems, the y- and z-polarized components of the transmitted field increase as the boundary and depth of phase of the DSE increase. When the phase boundary is smaller and the depth of phase depth is close to {pi}, super-resolving effect of DSE is more obvious but the intensity of sidelobes is larger for the high-NA system. In this way, it may be possible to improve both the resolution and focal depth of the SIL with high-NA systems.

  7. Characterization of X-Ray Diffraction System with a Microfocus X-Ray Source and a Polycapillary Optic

    Science.gov (United States)

    Gubarev, Mikhail; Marshall, Joy K.; Ciszak, Ewa; Ponomarev, Igor

    2000-01-01

    We present here an optimized microfocus x-ray source and polycapillary optic system designed for diffraction of small protein crystals. The x-ray beam is formed by a 5.5mm focal length capillary collimator coupled with a 40 micron x-ray source operating at 46Watts. Measurements of the x-ray flux, the divergence and the spectral characteristics of the beam are presented, This optimized system provides a seven fold greater flux than our recently reported configuration [M. Gubarev, et al., J. of Applied Crystallography (2000) 33, in press]. We now make a comparison with a 5kWatts rotating anode generator (Rigaku) coupled with confocal multilayer focusing mirrors (Osmic, CMF12- 38Cu6). The microfocus x-ray source and polycapillary collimator system delivers 60% of the x-ray flux from the rotating anode system. Additional ways to improve our microfocus x-ray system, and thus increase the x-ray flux will be discussed.

  8. 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.)

  9. Spectral and angular dependences of the efficiency of relief-phase diffractive lenses with two- and three-layer microstructures

    Science.gov (United States)

    Greisukh, G. I.; Danilov, V. A.; Ezhov, E. G.; Stepanov, S. A.; Usievich, B. A.

    2015-06-01

    The efficiency of diffractive lenses with two-layer single-relief and three-layer double-relief microstructures is studied. Studies are carried out using the scalar and electromagnetic diffraction theories. Depending on the requirements for the diffractive lens, the theories permit one to justifiably choose the configuration, optical materials, and constructive parameters of the microstructure, as well as to determine the real maximum allowable angle of radiation incidence on the diffractive lens with the microstructure of a particular type.

  10. Macro-Bending Influence on Radiation Induced Attenuation Measurement in Optical Fibres

    CERN Document Server

    Guillermain, E; Ricci, D; Weinand, U

    2014-01-01

    Influence of the bending radius on the measurement of radiation induced attenuation in glass optical fibres is discussed in this paper. Radiation induced attenuation measured in two single-mode fibre types shows discrepancies when coiled around a low bending radius spool: the observed attenuation is lower than expected. A series of dedicated tests reveals that this invalid measurement is related to the displacement of the mode field towards the cladding when the fibre is bent with a low radius, and to the different radiation resistances of the core and cladding glasses. For irradiation tests of optical fibres, the spool radius should therefore be carefully chosen.

  11. Improved Framework for Tractography Reconstruction of the Optic Radiation.

    Directory of Open Access Journals (Sweden)

    Eloy Martínez-Heras

    Full Text Available The optic radiation (OR is one of the major components of the visual system and a key structure at risk in white matter diseases such as multiple sclerosis (MS. However, it is challenging to perform track reconstruction of the OR using diffusion MRI due to a sharp change of direction in the Meyer's loop and the presence of kissing and crossing fibers along the pathway. As such, we aimed to provide a highly precise and reproducible framework for tracking the OR from thalamic and visual cortex masks. The framework combined the generation of probabilistic streamlines by high order fiber orientation distributions estimated with constrained spherical deconvolution and an automatic post-processing based on anatomical exclusion criteria (AEC to compensate for the presence of anatomically implausible streamlines. Specifically, those ending in the contralateral hemisphere, cerebrospinal fluid or grey matter outside the visual cortex were automatically excluded. We applied the framework to two distinct high angular resolution diffusion-weighted imaging (HARDI acquisition protocols on one cohort, comprised of ten healthy volunteers and five MS patients. The OR was successfully delineated in both HARDI acquisitions in the healthy volunteers and MS patients. Quantitative evaluation of the OR position was done by comparing the results with histological reference data. Compared with histological mask, the OR reconstruction into a template (OR-TCT was highly precise (percentage of voxels within the OR-TCT correctly defined as OR, ranging from 0.71 to 0.83. The sensitivity (percentage of voxels in histological reference mask correctly defined as OR in OR-TCT ranged from 0.65 to 0.81 and the accuracy (measured by F1 score was 0.73 to 0.77 in healthy volunteers. When AEC was not applied the precision and accuracy decreased. The absolute agreement between both HARDI datasets measured by the intraclass correlation coefficient was 0.73. This improved framework

  12. 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

  13. The Impacts of Optical Properties on Radiative Forcing Due to Dust Aerosol

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; SHI Guangyu; LI Shuyan; LI Wei; WANG Biao; HUANG Yanbin

    2006-01-01

    There are large uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol. The optical properties contribute much to those uncertainties. The authors perform several sensitivity experiments to estimate the impacts of optical characteristics on regional radiative forcing in this paper. The experiments involve in refractive indices, single scattering albedo, asymmetry factor and optical depth. An updated dataset of refractive indices representing East Asian dust and the one recommended by the World Meteorology Organization (WMO) are contrastively analyzed and used. A radiative transfer code for solar and thermal infrared radiation with detailed aerosol parameterization is employed. The strongest emphasis is on the refractive indices since other optical parameters strongly depend on it, and the authors found a strong sensitivity of radiative forcing on refractive indices. Studies show stronger scattering, weaker absorption and forward scattering of the East Asian dust particles at solar wavelengths, which leads to higher negative forcing, lower positive forcing and bigger net forcing at the top of the atmosphere (TOA) than that of the WMO dust model. It is also found that the TOA forcings resulting from these two dust models have opposite signs in certain regions, which implies the importance of accurate measurements of optical properties in the quantitative estimation of radiative forcing.

  14. Single Particle X-ray Diffractive Imaging

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-10-01

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

  15. Focusing of light beyond the diffraction limit

    CERN Document Server

    Chen, K R

    2009-01-01

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

  16. Diffusion tensor imaging for in vivo detection of degenerated optic radiation.

    Science.gov (United States)

    Michelson, Georg; Engelhorn, Tobias; Waerntges, Simone; Doerfler, Arnd

    2011-01-01

    Glaucomatous optic nerve atrophy may continue to the linked optic radiation by transneuronal degeneration, as described in animal models of glaucoma. In vivo visualization of the visual pathway represents a new challenge in the field of ophthalmology. We present a new approach for illustration of the optic radiation by diffusion tensor imaging (DTI) based on magnetic resonance imaging (MRI). The DTI was established by use of a 3T high-field scanner. The case of a patient with primary open-angle glaucoma is opposed to this one of a healthy subject to demonstrate the visible rarefication of the optic radiation. The goal was to introduce the technique of the DTI also in ophthalmology and to demonstrate that it may be useful to judge glaucoma-related differences.

  17. Hyperspectral optical diffraction tomography

    CERN Document Server

    Jung, JaeHwang; Yoon, Jonghee; Park, YongKeun

    2015-01-01

    Here, we present a novel microscopic technique for measuring wavelength-dependent three-dimensional (3-D) distributions of the refractive indices (RIs) of microscopic samples in the visible wavelengths. Employing 3-D quantitative phase microscopy techniques with a wavelength-swept source, 3-D RI tomograms were obtained in the range of 450 - 700 nm with a spectral resolution of a few nanometers. The capability of the technique was demonstrated by measuring the hyperspectral 3-D RI tomograms of polystyrene beads, human red blood cells, and hepatocytes. The results demonstrate the potential for label-free molecular specific 3-D tomography of biological samples.

  18. Real-time fibre optic radiation dosimeters for nuclear environment monitoring around thermonuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. Fernandez; Brichard, B. [SCK .CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium); O' Keeffe, S.; Fitzpatrick, C.; Lewis, E. [Electronic and Computer Engineering Department, University of Limerick, Limerick (Ireland); Vaille, J.-R.; Dusseau, L. [CEM2-Universite Montpellier II, cc083 place E. Bataillon, 34095 Montpellier Cedex 05 (France); Jackson, D.A. [School of Physical Sciences, University of Kent, Kent CT2 7NR (United Kingdom); Ravotti, F.; Glaser, M. [European Organization for Nuclear Research CERN, TS-LEA-RAD/PH-DT2-SD, CH-1211 Geneva 23 (Switzerland); El-Rabii, H. [Laboratoire de Combustion et de Detonique, ENSMA/CNRS, 1 av. Clement Ader, 86961 Chasseneuil-Futuroscope (France)], E-mail: afernand@sckcen.be

    2008-01-15

    The ability of fibre optic sensors to operate in hazardous nuclear environments and their intrinsic immunity to electro-magnetic interference make fibre optic sensing a very promising technology for the future ITER thermonuclear fusion reactor. In this paper, we evaluate fibre optic sensing technology for monitoring radiation dose in the vicinity of ITER during its operation and during the maintenance periods. First, the performance of an OSL dosimeter interrogated remotely using radiation tolerant optical fibres is evaluated both for real-time and integrating measurements for doses exceeding 100 Gy. We demonstrate its satisfactory operation in a mixed gamma neutron field. Second, we discuss the successful calibration of a new scintillating fibre optic radiation probe based on CsI(TI) crystals for operation in the dose-rate range 0.3-3000 mGy/h. The CsI(TI) crystal scintillator is mounted at the end of a 10-m long multimode fibre transceiver link to allow for remote deployment. The probes can detect and measure gamma dose rates ranging from 1 to 1000 mGy/h. Finally, we investigate the possible use of commercially available PMMA plastic optical fibres as on-line dosimeters up to 34 kGy. The dose measurement is derived from the radiation-induced attenuation in the optical fibre itself. A novel interrogation scheme based on a ratiometric technique is proposed for real-time dosimetry.

  19. Stretching and squeezing of sessile dielectric drops by the optical radiation pressure.

    Science.gov (United States)

    Chraïbi, Hamza; Lasseux, Didier; Arquis, Eric; Wunenburger, Régis; Delville, Jean-Pierre

    2008-06-01

    We study numerically the deformation of sessile dielectric drops immersed in a second fluid when submitted to the optical radiation pressure of a continuous Gaussian laser wave. Both drop stretching and drop squeezing are investigated at steady state where capillary effects balance the optical radiation pressure. A boundary integral method is implemented to solve the axisymmetric Stokes flow in the two fluids. In the stretching case, we find that the drop shape goes from prolate to near-conical for increasing optical radiation pressure whatever the drop to beam radius ratio and the refractive index contrast between the two fluids. The semiangle of the cone at equilibrium decreases with the drop to beam radius ratio and is weakly influenced by the index contrast. Above a threshold value of the radiation pressure, these "optical cones" become unstable and a disruption is observed. Conversely, when optically squeezed, the drop shifts from an oblate to a concave shape leading to the formation of a stable "optical torus." These findings extend the electrohydrodynamics approach of drop deformation to the much less investigated "optical domain" and reveal the openings offered by laser waves to actively manipulate droplets at the micrometer scale.

  20. Optical Real-Time Space Radiation Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Real-time dosimetry is needed to provide immediate feedback, so astronauts can minimize their exposure to ionizing radiation during periods of high solar activity....