WorldWideScience

Sample records for optical sources

  1. Optically pumped terahertz sources

    Institute of Scientific and Technical Information of China (English)

    ZHONG Kai; SHI Wei; XU DeGang; LIU PengXiang; WANG YuYe; MEI JiaLin; YAN Chao; FU ShiJie; YAO JianQuan

    2017-01-01

    High-power terahertz (THz) generation in the frequency range of0.1-10 THz has been a fast-developing research area ever since the beginning of the THz boom two decades ago,enabling new technological breakthroughs in spectroscopy,communication,imaging,etc.By using optical (laser) pumping methods with near-or mid-infrared (IR) lasers,flexible and practical THz sources covering the whole THz range can be realized to overcome the shortage of electronic THz sources and now they are playing important roles in THz science and technology.This paper overviews various optically pumped THz sources,including femtosecond laser based ultrafast broadband THz generation,monochromatic widely tunable THz generation,single-mode on-chip THz source from photomixing,and the traditional powerful THz gas lasers.Full descriptions from basic principles to the latest progress are presented and their advantages and disadvantages are discussed as well.It is expected that this review gives a comprehensive reference to researchers in this area and additionally helps newcomers to quickly gain understanding of optically pumped THz sources.

  2. Optical surfacing via linear ion source

    International Nuclear Information System (INIS)

    Wu, Lixiang; Wei, Chaoyang; Shao, Jianda

    2017-01-01

    We present a concept of surface decomposition extended from double Fourier series to nonnegative sinusoidal wave surfaces, on the basis of which linear ion sources apply to the ultra-precision fabrication of complex surfaces and diffractive optics. The modified Fourier series, or sinusoidal wave surfaces, build a relationship between the fabrication process of optical surfaces and the surface characterization based on power spectral density (PSD) analysis. Also, we demonstrate that the one-dimensional scanning of linear ion source is applicable to the removal of mid-spatial frequency (MSF) errors caused by small-tool polishing in raster scan mode as well as the fabrication of beam sampling grating of high diffractive uniformity without a post-processing procedure. The simulation results show that optical fabrication with linear ion source is feasible and even of higher output efficiency compared with the conventional approach.

  3. Optical surfacing via linear ion source

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lixiang, E-mail: wulx@hdu.edu.cn [Key Lab of RF Circuits and Systems of Ministry of Education, Zhejiang Provincial Key Lab of LSI Design, Microelectronics CAD Center, College of Electronics and Information, Hangzhou Dianzi University, Hangzhou (China); Wei, Chaoyang, E-mail: siomwei@siom.ac.cn [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Shao, Jianda, E-mail: jdshao@siom.ac.cn [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2017-04-15

    We present a concept of surface decomposition extended from double Fourier series to nonnegative sinusoidal wave surfaces, on the basis of which linear ion sources apply to the ultra-precision fabrication of complex surfaces and diffractive optics. The modified Fourier series, or sinusoidal wave surfaces, build a relationship between the fabrication process of optical surfaces and the surface characterization based on power spectral density (PSD) analysis. Also, we demonstrate that the one-dimensional scanning of linear ion source is applicable to the removal of mid-spatial frequency (MSF) errors caused by small-tool polishing in raster scan mode as well as the fabrication of beam sampling grating of high diffractive uniformity without a post-processing procedure. The simulation results show that optical fabrication with linear ion source is feasible and even of higher output efficiency compared with the conventional approach.

  4. Optically pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Anderson, L.W.

    1986-01-01

    The current status and future prospects for the optically pumped polarized H - ion source are discussed. At the present time H - ion currents of 60 μA and with a polarization of 65% have been produced. The ion current and polarization can be increased significantly if the optically pumped Na charge exchange target density and polarization can be increased. Studies of wall surfaces that permit many bounces before depolarizing the Na electron spin and studies of radiation trapping in optically pumped Na indicate that the Na target density and polarization can be increased substantially. 27 refs., 6 figs., 2 tabs

  5. Performance improvement of optical semiconductor sources

    International Nuclear Information System (INIS)

    El Tokhy, M.E.M.E

    2009-01-01

    This thesis has been concerned with a detailed study of nano-technology quantum sources. From these sources, quantum cascaded laser (QCLs) and quantum dot lasers (QDs), are studied theoretically. Block diagram models based on VisSim environment in junction with mathematical models are developed to analyze these kinds of optical sources. The mathematical model is derived to express explicitly the performance of the device, while a block diagram model is implemented which implicitly describe the same device. By using these mathematical models, new expressions are obtained. Accurate and efficient modeling of these sources is being increasingly important in the design and optimization of optical integrated circuits and circuit component. In the case of QCLs, the diagram is used to calculate its characteristics such as potential voltage, output optical power, current, threshold current density, slope efficiency, differential efficiency, and optical gain of these devices. Furthermore, the effect of each parameter of the QCLs, such as number of periods; N p , operating temperature; T, waveguide losses; α w , mirror losses; α m , on its performance are discussed in details. To demonstrate these effects further, the changes in three dimensional are plotted. In another mean, improving the lasing properties of the QCLs through both block diagram and mathematical models is the main scope in this thesis. In order to enhance the performance of the underlined device, mathematical model parameters are tuned to obtain the optimum behavior. Additionally, it is important to model and analyze the effects of these physical parameters on the performance of QCLs. These parameters play the central role in specifying the optical characteristics of the considered laser source. Proposed relation that linked emitted power with QCLs parameters is deduced. Moreover, it is important to have a large amount of radiated power, where increasing the amount of radiated power represents the main

  6. SLC polarized beam source electron optics design

    International Nuclear Information System (INIS)

    Eppley, K.R.; Lavine, T.L.; Early, R.A.; Herrmannsfeldt, W.B.; Miller, R.H.; Schultz, D.C.; Spencer, C.M.; Yeremian, A.D.

    1991-05-01

    This paper describes the design of the beam-line from the polarized electron gun to the linac injector in the Stanford Linear Collider (SLC). The polarized electron source is a GaAs photocathode, requiring 10 -11 -Torr-range pressure for adequate quantum efficiency and longevity. The photocathode is illuminated by 3-nsec-long laser pulses. The quality of the optics for the 160-kV beam is crucial since electron-stimulated gas desorption from beam loss in excess of 0.1% of the 20-nC pulses may poison the photocathode. Our design for the transport line consists of a differential pumping region isolated by a pair of valves. Focusing is provided by a pair of Helmholtz coils and by several iron-encased solenoidal lenses. Our optics design is based on beam transport simulations using 2 1/2-D particle-in-cell codes to model the gun and to solve the fully-relativistic time-dependent equations of motion in three dimensions for electrons in the presence of azimuthally symmetric electromagnetic fields. 6 refs., 6 figs

  7. Functional swept source optical coherence tomography

    International Nuclear Information System (INIS)

    Blatter, C.

    2013-01-01

    Optical coherence tomography (OCT) is a non-invasive imaging modality capable of providing information about a sample structure along the three spatial dimensions with micrometer scale resolution. A new chapter opened with the development of functional OCT that provides additional information to the standard structural imaging. Among those extensions is Doppler OCT (D-OCT) that yields knowledge about the motion of the sample and/or its substructure. Its main application in biomedical imaging is the assessment of blood flow. D-OCT is therefore often associated with blood velocity measurement and recently with the visualization of the vascular network. Blood flow and vasculature are important markers of tissue health. Their assessment provides crucial information for diagnostics, treatment planning and monitoring. OCT is in a good position, as a non-invasive technique, to become an alternative to current fluorescence based techniques, allowing thereby also more frequent examination and broader screenings and, as a high resolution modality, to give insight into potential changes at the capillary level. An important challenge of in vivo imaging is patient motion that decreases the quality of acquisitions. One solution to that issue is high-speed imaging. Recently swept source OCT (SSOCT) revealed to be an efficient technology to achieve high-speed. This thesis investigates the use of swept sources for qualitative and quantitative vasculature imaging. It is presented via five journal papers that form its backbone. Prior to that, main concepts of FDOCT, D-OCT and SS systems are presented. The first paper reports a SSOCT system for skin imaging. In standard OCT systems, improving the lateral resolution comes at a cost of reduced depth of focus. This should be avoided in order to be able to assess different vascular beds in depth while keeping the speed advantage of FDOCT. Employing a Bessel beam for illumination of the sample allows circumventing this issue. The image

  8. Optical observations of binary X-ray sources

    International Nuclear Information System (INIS)

    Boynton, P.E.

    1975-01-01

    The contribution to the recent progress in astronomy made by optical observations is pointed out. The optical properties of X-ray sources help to establish the physical nature of these objects. The current observational evidence on the binary X-ray sources HZ Her/Her X-1 and HDE 226868/Cyg X-1 is reported. (P.J.S.)

  9. An optical system for controlling ion source parameters

    International Nuclear Information System (INIS)

    Zhang Baifang; Liu Zhenhao; Jiang Yi; Xu Zhengjia

    1999-01-01

    An optical control system used for adjusting the source's parameters of an ion separator is described. There are two slice microcomputers at HV terminal and the ground respectively. These microcomputers communicate each other with the full-duplex mode through two pieces of optical fiber, in which many parameters are time-share transmitted in the form of optical pulse. This system can stabilize the arc current and temperature, adjust and display all parameters and has safe-guard ability. At HV terminal, the optical coupling technique is used for connecting the CPU and the ion source, and at the ground the CPU can communicate with a control microcomputer

  10. Optical laser systems at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E.; Fry, Alan R., E-mail: alanfry@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-22

    This manuscript serves as a reference to describe the optical laser sources and capabilities at the Linac Coherent Light Source. Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS.

  11. Open-Source 3D-Printable Optics Equipment

    Science.gov (United States)

    Zhang, Chenlong; Anzalone, Nicholas C.; Faria, Rodrigo P.; Pearce, Joshua M.

    2013-01-01

    Just as the power of the open-source design paradigm has driven down the cost of software to the point that it is accessible to most people, the rise of open-source hardware is poised to drive down the cost of doing experimental science to expand access to everyone. To assist in this aim, this paper introduces a library of open-source 3-D-printable optics components. This library operates as a flexible, low-cost public-domain tool set for developing both research and teaching optics hardware. First, the use of parametric open-source designs using an open-source computer aided design package is described to customize the optics hardware for any application. Second, details are provided on the use of open-source 3-D printers (additive layer manufacturing) to fabricate the primary mechanical components, which are then combined to construct complex optics-related devices. Third, the use of the open-source electronics prototyping platform are illustrated as control for optical experimental apparatuses. This study demonstrates an open-source optical library, which significantly reduces the costs associated with much optical equipment, while also enabling relatively easily adapted customizable designs. The cost reductions in general are over 97%, with some components representing only 1% of the current commercial investment for optical products of similar function. The results of this study make its clear that this method of scientific hardware development enables a much broader audience to participate in optical experimentation both as research and teaching platforms than previous proprietary methods. PMID:23544104

  12. Open-source 3D-printable optics equipment.

    Science.gov (United States)

    Zhang, Chenlong; Anzalone, Nicholas C; Faria, Rodrigo P; Pearce, Joshua M

    2013-01-01

    Just as the power of the open-source design paradigm has driven down the cost of software to the point that it is accessible to most people, the rise of open-source hardware is poised to drive down the cost of doing experimental science to expand access to everyone. To assist in this aim, this paper introduces a library of open-source 3-D-printable optics components. This library operates as a flexible, low-cost public-domain tool set for developing both research and teaching optics hardware. First, the use of parametric open-source designs using an open-source computer aided design package is described to customize the optics hardware for any application. Second, details are provided on the use of open-source 3-D printers (additive layer manufacturing) to fabricate the primary mechanical components, which are then combined to construct complex optics-related devices. Third, the use of the open-source electronics prototyping platform are illustrated as control for optical experimental apparatuses. This study demonstrates an open-source optical library, which significantly reduces the costs associated with much optical equipment, while also enabling relatively easily adapted customizable designs. The cost reductions in general are over 97%, with some components representing only 1% of the current commercial investment for optical products of similar function. The results of this study make its clear that this method of scientific hardware development enables a much broader audience to participate in optical experimentation both as research and teaching platforms than previous proprietary methods.

  13. Open-source 3D-printable optics equipment.

    Directory of Open Access Journals (Sweden)

    Chenlong Zhang

    Full Text Available Just as the power of the open-source design paradigm has driven down the cost of software to the point that it is accessible to most people, the rise of open-source hardware is poised to drive down the cost of doing experimental science to expand access to everyone. To assist in this aim, this paper introduces a library of open-source 3-D-printable optics components. This library operates as a flexible, low-cost public-domain tool set for developing both research and teaching optics hardware. First, the use of parametric open-source designs using an open-source computer aided design package is described to customize the optics hardware for any application. Second, details are provided on the use of open-source 3-D printers (additive layer manufacturing to fabricate the primary mechanical components, which are then combined to construct complex optics-related devices. Third, the use of the open-source electronics prototyping platform are illustrated as control for optical experimental apparatuses. This study demonstrates an open-source optical library, which significantly reduces the costs associated with much optical equipment, while also enabling relatively easily adapted customizable designs. The cost reductions in general are over 97%, with some components representing only 1% of the current commercial investment for optical products of similar function. The results of this study make its clear that this method of scientific hardware development enables a much broader audience to participate in optical experimentation both as research and teaching platforms than previous proprietary methods.

  14. Optical Imaging of Ionizing Radiation from Clinical Sources.

    Science.gov (United States)

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

    2016-11-01

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

  15. Dual Optical Comb LWIR Source and Sensor

    Science.gov (United States)

    2017-10-12

    Justin M. Brown, Mark G. Allen Physical Sciences Inc. (PSI) Pierre Jouy, Jérôme Faist Swiss Federal Institute of Technology (ETH) Markus Geiser...Research, Development & Engineering Center Name of Contractor: Physical Sciences Inc. Principal Investigator: Dr. Joel M. Hensley Business...including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and

  16. Optical identifications of flat-spectrum radio sources

    International Nuclear Information System (INIS)

    Condon, J.J.; Condon, M.A.; Broderick, J.J.; Davis, M.M.

    1983-01-01

    A complete sample of radio sources with S> or =0.3 Jy at 1400 MHz, +24 0 0 , and low-frequency spectral indices α(408, 1400) or =+0.5 are usually in empty fields. The lower limits that can be assigned to the radio-optical spectral indices α/sub RO/ of these sources are significantly higher than the median α/sub RO/ of the sources with flat high-frequency spectra, so the optical characteristics of the two classes of radio source are intrinsically different. The radio and optical fluxes of flat-spectrum QSO's appear to be correlated, at least when averaged over 10 2 --10 3 yr

  17. Optical Characteristics of a Multichannel Hybrid Integrated Light Source for Ultra-High-Bandwidth Optical Interconnections

    Directory of Open Access Journals (Sweden)

    Takanori Shimizu

    2015-11-01

    Full Text Available The optical characteristics of a multi-channel hybrid integrated light source were described for an optical interconnection with a bandwidth of over 10 Tbit/s. The power uniformity of the relative intensity of a 1000-channel light source was shown, and the minimum standard deviation s of the optical power of the 200 output ports at each 25-channel laser diode (LD array was estimated to be 0.49 dB. This hybrid integrated light source is expected to be easily adaptable to a photonics-electronics convergence system for ultra-high-bandwidth interchip interconnections.

  18. Ion optics in an ion source system

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Salam, F W; Moustafa, O A; El-Khabeary, H [Accelerators Dept, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1997-12-31

    An analysis of ion beams from an ion source which consisted of a hemispherical anode, a plane earthed cathode, and a focusing electrode has been carried out. The focal properties of such electrode arrangement were studied using axially symmetric fields. Axial and radial electric fields were obtained as functions of the axial distance. It was found that the radial component of the gradient of potential pushes the ions towards the axis, which indicates the convergent action of the system. The effect of voltage variation between the boundary and the focusing electrode on the position of the plasma boundary are given using the experimental data of the ion source characteristics and its geometrical parameters. The advantages of plasma diffusing outside the source through a small aperture were used by applying a potential to the focusing electrode. It was possible to extract a large ion current from the expanded plasma. The system constituted a lens with a focal length of 29.4 mm. 7 figs.

  19. Optical observations of binary X-ray sources

    International Nuclear Information System (INIS)

    Charles, P.

    1982-01-01

    Here I shall consider only those systems where the compact object is a neutron star (or in a few cases perhaps a black hole). Since van Paradijs (1982) has recently produced an excellent and comprehensive review of optical observations of compact galactic X-ray sources I shall summarise the basic properties of the optical counterparts and discuss a few representative systems in some detail. (orig./WL)

  20. Simulated nuclear optical signatures using explosive light sources (ELS)

    International Nuclear Information System (INIS)

    Glaser, R.F.

    1979-05-01

    Four Explosive Light Source (aluminium powder and oxygen) tests were conducted on the test range at Sandia Laboratories in Albuquerque (SLA) from 28 February through 7 March 1978. Although several types of measuring devices were used, the report documents only the optical time histories measured by the bhangmeters and the NBDS, and explains the conclusions reached. In general, the four shots made it possible to gather clear-air optical transmission data, determine the suitability of ELS to simulate the optical effects of a nuclear burst, and provide experience for the larger scale ELS tests to be conducted at Fort Ord, CA in April

  1. Subcarrier multiplexing tolerant dispersion transmission system employing optical broadband sources.

    Science.gov (United States)

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2009-03-16

    This paper presents a novel SCM optical transmission system for next-generation WDM-PONs combining broadband optical sources and a Mach-Zehnder interferometric structure. The approach leeds to transport RF signals up to 50 GHz being compatible with RoF systems since a second configuration has been proposed in order to overcome dispersion carrier suppression effect using DSB modulation. The theoretical analysis validates the potentiality of the system also considering the effects of the dispersion slope over the transmission window. (c) 2009 Optical Society of America

  2. Simulated nuclear optical signatures using explosive light sources (ELS)

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, R.F.

    1979-05-01

    Four Explosive Light Source (aluminium powder and oxygen) tests were conducted on the test range at Sandia Laboratories in Albuquerque (SLA) from 28 February through 7 March 1978. Although several types of measuring devices were used, the report documents only the optical time histories measured by the bhangmeters and the NBDS, and explains the conclusions reached. In general, the four shots made it possible to gather clear-air optical transmission data, determine the suitability of ELS to simulate the optical effects of a nuclear burst, and provide experience for the larger scale ELS tests to be conducted at Fort Ord, CA in April.

  3. A dual-optically-pumped polarized negative deuterium ion source

    International Nuclear Information System (INIS)

    Kinsho, M.; Mori, Y.; Ikegami, K.; Takagi, A.

    1994-01-01

    An optically pumped polarized H - source (OPPIS), which is based on the charge exchange between H + ions and electron-spin-polarized alkali atoms has been developed at KEK. Just by applying this scheme to a deuteron beam, it is difficult to obtain a highly vector polarized deuteron beam. To obtain highly vector polarized D - ions, we have developed a 'dual optical pumping type' of polarized D - source. With this scheme, a 100% vector nuclear-spin polarization for D - ions is possible in principle. In a preliminary experiment, a 60% of vector nuclear-spin polarized D - ions was obtained. (author)

  4. Micro-combs: A novel generation of optical sources

    Science.gov (United States)

    Pasquazi, Alessia; Peccianti, Marco; Razzari, Luca; Moss, David J.; Coen, Stéphane; Erkintalo, Miro; Chembo, Yanne K.; Hansson, Tobias; Wabnitz, Stefan; Del'Haye, Pascal; Xue, Xiaoxiao; Weiner, Andrew M.; Morandotti, Roberto

    2018-01-01

    The quest towards the integration of ultra-fast, high-precision optical clocks is reflected in the large number of high-impact papers on the topic published in the last few years. This interest has been catalysed by the impact that high-precision optical frequency combs (OFCs) have had on metrology and spectroscopy in the last decade [1-5]. OFCs are often referred to as optical rulers: their spectra consist of a precise sequence of discrete and equally-spaced spectral lines that represent precise marks in frequency. Their importance was recognised worldwide with the 2005 Nobel Prize being awarded to T.W. Hänsch and J. Hall for their breakthrough in OFC science [5]. They demonstrated that a coherent OFC source with a large spectrum - covering at least one octave - can be stabilised with a self-referenced approach, where the frequency and the phase do not vary and are completely determined by the source physical parameters. These fully stabilised OFCs solved the challenge of directly measuring optical frequencies and are now exploited as the most accurate time references available, ready to replace the current standard for time. Very recent advancements in the fabrication technology of optical micro-cavities [6] are contributing to the development of OFC sources. These efforts may open up the way to realise ultra-fast and stable optical clocks and pulsed sources with extremely high repetition-rates, in the form of compact and integrated devices. Indeed, the fabrication of high-quality factor (high-Q) micro-resonators, capable of dramatically amplifying the optical field, can be considered a photonics breakthrough that has boosted not only the scientific investigation of OFC sources [7-13] but also of optical sensors and compact light modulators [6,14]. In this framework, the demonstration of planar high-Q resonators, compatible with silicon technology [10-14], has opened up a unique opportunity for these devices to provide entirely new capabilities for photonic

  5. Miniaturized and general purpose fiber optic ultrasonic sources

    International Nuclear Information System (INIS)

    Biagi, E.; Fontani, S.; Masotti, L.; Pieraccini, M.

    1997-01-01

    Innovative photoacoustic sources for ultrasonic NDE, smart structure, and clinical diagnosis are proposed. The working principle is based on thermal conversion of laser pulses into a metallic film evaporated directly onto the tip of a fiber optic. Unique features of the proposed transducers are very high miniaturization and potential easy embedding in smart structure. Additional advantages, high bedding in smart structure. Additional advantages, high ultrasonic frequency, large and flat bandwidth. All these characteristics make the proposed device an ideal ultrasonic source

  6. Optical linear algebra processors - Noise and error-source modeling

    Science.gov (United States)

    Casasent, D.; Ghosh, A.

    1985-01-01

    The modeling of system and component noise and error sources in optical linear algebra processors (OLAPs) are considered, with attention to the frequency-multiplexed OLAP. General expressions are obtained for the output produced as a function of various component errors and noise. A digital simulator for this model is discussed.

  7. Optical linear algebra processors: noise and error-source modeling.

    Science.gov (United States)

    Casasent, D; Ghosh, A

    1985-06-01

    The modeling of system and component noise and error sources in optical linear algebra processors (OLAP's) are considered, with attention to the frequency-multiplexed OLAP. General expressions are obtained for the output produced as a function of various component errors and noise. A digital simulator for this model is discussed.

  8. X-ray Optics for BES Light Source Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Dennis [Argonne National Lab. (ANL), Argonne, IL (United States); Padmore, Howard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lessner, Eliane [Dept. of Energy (DOE), Washington DC (United States). Office of Science

    2013-03-27

    Each new generation of synchrotron radiation sources has delivered an increase in average brightness 2 to 3 orders of magnitude over the previous generation. The next evolution toward diffraction-limited storage rings will deliver another 3 orders of magnitude increase. For ultrafast experiments, free electron lasers (FELs) deliver 10 orders of magnitude higher peak brightness than storage rings. Our ability to utilize these ultrabright sources, however, is limited by our ability to focus, monochromate, and manipulate these beams with X-ray optics. X-ray optics technology unfortunately lags behind source technology and limits our ability to maximally utilize even today’s X-ray sources. With ever more powerful X-ray sources on the horizon, a new generation of X-ray optics must be developed that will allow us to fully utilize these beams of unprecedented brightness. The increasing brightness of X-ray sources will enable a new generation of measurements that could have revolutionary impact across a broad area of science, if optical systems necessary for transporting and analyzing X-rays can be perfected. The high coherent flux will facilitate new science utilizing techniques in imaging, dynamics, and ultrahigh-resolution spectroscopy. For example, zone-plate-based hard X-ray microscopes are presently used to look deeply into materials, but today’s resolution and contrast are restricted by limitations of the current lithography used to manufacture nanodiffractive optics. The large penetration length, combined in principle with very high spatial resolution, is an ideal probe of hierarchically ordered mesoscale materials, if zone-plate focusing systems can be improved. Resonant inelastic X-ray scattering (RIXS) probes a wide range of excitations in materials, from charge-transfer processes to the very soft excitations that cause the collective phenomena in correlated electronic systems. However, although RIXS can probe high-energy excitations, the most exciting and

  9. X-ray Optics for BES Light Source Facilities

    International Nuclear Information System (INIS)

    Mills, Dennis; Padmore, Howard; Lessner, Eliane

    2013-01-01

    Each new generation of synchrotron radiation sources has delivered an increase in average brightness 2 to 3 orders of magnitude over the previous generation. The next evolution toward diffraction-limited storage rings will deliver another 3 orders of magnitude increase. For ultrafast experiments, free electron lasers (FELs) deliver 10 orders of magnitude higher peak brightness than storage rings. Our ability to utilize these ultrabright sources, however, is limited by our ability to focus, monochromate, and manipulate these beams with X-ray optics. X-ray optics technology unfortunately lags behind source technology and limits our ability to maximally utilize even today's X-ray sources. With ever more powerful X-ray sources on the horizon, a new generation of X-ray optics must be developed that will allow us to fully utilize these beams of unprecedented brightness. The increasing brightness of X-ray sources will enable a new generation of measurements that could have revolutionary impact across a broad area of science, if optical systems necessary for transporting and analyzing X-rays can be perfected. The high coherent flux will facilitate new science utilizing techniques in imaging, dynamics, and ultrahigh-resolution spectroscopy. For example, zone-plate-based hard X-ray microscopes are presently used to look deeply into materials, but today's resolution and contrast are restricted by limitations of the current lithography used to manufacture nanodiffractive optics. The large penetration length, combined in principle with very high spatial resolution, is an ideal probe of hierarchically ordered mesoscale materials, if zone-plate focusing systems can be improved. Resonant inelastic X-ray scattering (RIXS) probes a wide range of excitations in materials, from charge-transfer processes to the very soft excitations that cause the collective phenomena in correlated electronic systems. However, although RIXS can probe high-energy excitations, the most exciting

  10. Programmable current source for diode lasers stabilized optical fiber

    International Nuclear Information System (INIS)

    Gomez, J.; Camas, J.; Garcia, L.

    2012-01-01

    In this paper, we present the electronic design of a programmable stabilized current source. User can access to the source through a password, which, it has a database with the current and voltage operating points. This source was successfully used as current source in laser diode in optical fiber sensors. Variations in the laser current were carried out by a monitoring system and a control of the Direct Current (DC), which flowing through a How land source with amplifier. The laser current can be stabilized with an error percent of ± 1 μA from the threshold current (Ith) to its maximum operation current (Imax) in DC mode. The proposed design is reliable, cheap, and its output signal of stabilized current has high quality. (Author)

  11. The TRIUMF optically-pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Levy, C.D.P.; Jayamanna, K.; McDonald, M.; Schmor, P.W.; Van Oers, W.T.H.; Welz, J.; Wight, G.W.; Dutto, G.; Zelenski, A.N.; Sakae, T.

    1995-09-01

    The TRIUMF dc optically-pumped polarized H - ion source (OPPIS) produces 200 μA dc H - current at 85% polarization within a normalized emittance (90%) of 0.8 π mm mrad, for operations at the TRIUMF cyclotron. As a result of development of the ECR primary proton source, 1.6 mA dc polarized H - current is produced within a normalized emittance of 2 π mm mrad, suitable for high energy accelerators. The OPPIS has also been developed for use in a parity non-conservation experiment which has very severe limits on permissible helicity-correlated changes in beam current and energy. (author)

  12. Possible power source found for fiber optic lasers

    International Nuclear Information System (INIS)

    Krupa, Tyler J.

    2000-01-01

    Scientists at the US Department of Energy's Sandia National Laboratory are researching ways to use a new semiconductor alloy, indium gallium arsenide nitride (InGaAsN), as as photovoltaic power source for lasers in fiber optics and space communication satellites. The efficiency of electricity-generating solar cells utilizing InGaAsN is predicted to be 40%-nearly twice the efficiency rate of a standard silicon solar cell. The use of InGaAsN in solar cells is a potential power source for satellites and other space systems. (AIP) (c)

  13. The TRIUMF optically-pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Levy, C.D.P.; Jayamanna, K.; McDonald, M.

    1995-09-01

    The TRIUMF dc optically-pumped polarized H - ion source (OPPIS) produces 200 microA dc H - current at 85% polarization within a normalized emittance (90%) of 0.8 π mm mrad, for operations at the TRIUMF cyclotron. As a result of development of the ECR primary proton source, 1.6 mA dc polarized H - current is produced within a normalized emittance of 2 π mm mrad, suitable for high energy accelerators. The OPPIS has also been developed for use in a parity non-conservation experiment which has very severe limits on permissible helicity-correlated changes in beam current and energy

  14. Tunable light source for fiber optic lighting applications

    Science.gov (United States)

    Narendran, Nadarajah; Bierman, Andrew; Finney, Mark J.; Edwards, Ian K.

    1997-09-01

    This paper examines the possibility of tuning the lamp spectrum to compensate for color distortions in fiber optic lighting systems. Because most optical fibers have strong absorption in the blue and red wavelength regions, white light entering and propagating down an optical fiber suffers varied amounts of attenuation as a function of wavelength. As a result, the light exiting the optical fiber has a greenish tint that the lighting design community considers undesirable in interior lighting applications. HID lamps are commonly used for the light source in this industry. Certain classes of HID lamps tend to shift in color when their operating position or the input voltage to the lamp is changed. An experimental study is being conducted to characterize the color shift properties of a small HID lamp as a function of tilt and input voltage. The study also examines the possibility of exploiting this color shift to compensate for the color distortions caused by optical fibers. The details of the experiment and the results are presented in this manuscript.

  15. A young source of optical emission from distant radio galaxies.

    Science.gov (United States)

    Hammer, F; Fèvre, O Le; Angonin, M C

    1993-03-25

    DISTANT radio galaxies provide valuable insights into the properties of the young Universe-they are the only known extended optical sources at high redshift and might represent an early stage in the formation and evolution of galaxies in general. This extended optical emission often has very complex morphologies, but the origin of the light is still unclear. Here we report spectroscopic observations for several distant radio galaxies (0.75≤ z ≤ 1.1) in which the rest-frame spectra exhibit featureless continua between 2,500 Å and 5,000 Å. We see no evidence for the break in the spectrum at 4,000 Å expected for an old stellar population 1-3 , and suggest that young stars or scattered emissions from the active nuclei are responsible for most of the observed light. In either case, this implies that the source of the optical emission is com-parable in age to the associated radio source, namely 10 7 years or less.

  16. Cost-Effective Brillouin Optical Time-Domain Analysis Sensor Using a Single Optical Source and Passive Optical Filtering

    Directory of Open Access Journals (Sweden)

    H. Iribas

    2016-01-01

    Full Text Available We present a simplified configuration for distributed Brillouin optical time-domain analysis sensors that aims to reduce the cost of the sensor by reducing the number of components required for the generation of the two optical waves involved in the sensing process. The technique is based on obtaining the pump and probe waves by passive optical filtering of the spectral components generated in a single optical source that is driven by a pulsed RF signal. The optical source is a compact laser with integrated electroabsorption modulator and the optical filters are based on fiber Bragg gratings. Proof-of-concept experiments demonstrate 1 m spatial resolution over a 20 km sensing fiber with a 0.9 MHz precision in the measurement of the Brillouin frequency shift, a performance similar to that of much more complex setups. Furthermore, we discuss the factors limiting the sensor performance, which are basically related to residual spectral components in the filtering process.

  17. Optical Performance of Carbon-Nanotube Electron Sources

    International Nuclear Information System (INIS)

    Jonge, Niels de; Allioux, Myriam; Oostveen, Jim T.; Teo, Kenneth B. K.; Milne, William I.

    2005-01-01

    The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter

  18. Joint optimization of source, mask, and pupil in optical lithography

    Science.gov (United States)

    Li, Jia; Lam, Edmund Y.

    2014-03-01

    Mask topography effects need to be taken into consideration for more advanced resolution enhancement techniques in optical lithography. However, rigorous 3D mask model achieves high accuracy at a large computational cost. This work develops a combined source, mask and pupil optimization (SMPO) approach by taking advantage of the fact that pupil phase manipulation is capable of partially compensating for mask topography effects. We first design the pupil wavefront function by incorporating primary and secondary spherical aberration through the coefficients of the Zernike polynomials, and achieve optimal source-mask pair under the condition of aberrated pupil. Evaluations against conventional source mask optimization (SMO) without incorporating pupil aberrations show that SMPO provides improved performance in terms of pattern fidelity and process window sizes.

  19. Application of optical emission spectroscopy to high current proton sources

    International Nuclear Information System (INIS)

    Castro, G; Mazzaglia, M; Nicolosi, D; Mascali, D; Reitano, R; Celona, L; Leonardi, O; Leone, F; Naselli, E; Neri, L; Torrisi, G; Gammino, S; Zaniol, B

    2017-01-01

    Optical Emission Spectroscopy (OES) represents a very reliable technique to carry out non-invasive measurements of plasma density and plasma temperature in the range of tens of eV. With respect to other diagnostics, it also can characterize the different populations of neutrals and ionized particles constituting the plasma. At INFN-LNS, OES techniques have been developed and applied to characterize the plasma generated by the Flexible Plasma Trap, an ion source used as 'testbench' of the proton source built for European Spallation Source. This work presents the characterization of the parameters of a hydrogen plasma in different conditions of neutral pressure, microwave power and magnetic field profile, along with perspectives for further upgrades of the OES diagnostics system. (paper)

  20. Fiber optic distributed temperature sensing for fire source localization

    Science.gov (United States)

    Sun, Miao; Tang, Yuquan; Yang, Shuang; Sigrist, Markus W.; Li, Jun; Dong, Fengzhong

    2017-08-01

    A method for localizing a fire source based on a distributed temperature sensor system is proposed. Two sections of optical fibers were placed orthogonally to each other as the sensing elements. A tray of alcohol was lit to act as a fire outbreak in a cabinet with an uneven ceiling to simulate a real scene of fire. Experiments were carried out to demonstrate the feasibility of the method. Rather large fluctuations and systematic errors with respect to predicting the exact room coordinates of the fire source caused by the uneven ceiling were observed. Two mathematical methods (smoothing recorded temperature curves and finding temperature peak positions) to improve the prediction accuracy are presented, and the experimental results indicate that the fluctuation ranges and systematic errors are significantly reduced. The proposed scheme is simple and appears reliable enough to locate a fire source in large spaces.

  1. Operation of the optically pumped polarized H- source at LAMPF

    International Nuclear Information System (INIS)

    York, R.L.; Tupa, D.; Swenson, D.R.; van Dyck, O.B.

    1991-01-01

    We report on the first five months of operation of the Optically Pumped Polarized Ion Source (OPPIS) for the nuclear physics research program at LAMPF. The LAMPF OPPIS is unique in using Ti: Sapphire lasers to polarize the potassium charge-exchange medium, and until recently was unique in using a superconducting magnet in the ECR source and polarizer regions. The ECR extraction electrode biasing arrangement is also unique. Typical performance was 25 microamps of peak current (measured at 750 keV) with 55% beam polarization or 15 microamps at 62%. Ion source availability was greater than 90%. We also report our planned improvements in preparation for research operation in May of 1991. 3 refs., 4 figs

  2. Water cooled metal optics for the Advanced Light Source

    International Nuclear Information System (INIS)

    McKinney, W.R.; Irick, S.C.; Lunt, D.L.J.

    1991-01-01

    The program for providing water cooled metal optics for the Advanced Light Source at Berkeley is reviewed with respect to fabrication and metrology of the surfaces. Materials choices, surface figure and smoothness specifications, and metrology systems for measuring the plated metal surfaces are discussed. Results from prototype mirrors and grating blanks will be presented, which show exceptionally low microroughness and mid-period error. We will briefly describe out improved version of the Long Trace Profiler, and its importance to out metrology program. We have completely redesigned the mechanical, optical and computational parts of the profiler system with the cooperation of Peter Takacs of Brookhaven, Continental Optical, and Baker Manufacturing. Most important is that one of our profilers is in use at the vendor to allow testing during fabrication. Metrology from the first water cooled mirror for an ALS beamline is presented as an example. The preplating processing and grinding and polishing were done by Tucson Optical. We will show significantly better surface microroughness on electroless nickel, over large areas, than has been reported previously

  3. Optical arc sensor using energy harvesting power source

    Science.gov (United States)

    Choi, Kyoo Nam; Rho, Hee Hyuk

    2016-06-01

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  4. Optical arc sensor using energy harvesting power source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Nam, E-mail: knchoi@inu.ac.kr; Rho, Hee Hyuk, E-mail: rdoubleh0902@inu.ac.kr [Dept. of Information and Telecommunication Engineering Incheon National University Incheon 22012 (Korea, Republic of)

    2016-06-03

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  5. A radio and optical study of Molonglo radio sources

    Science.gov (United States)

    Ishwara-Chandra, C. H.; Saikia, D. J.; McCarthy, P. J.; van Breugel, W. J. M.

    2001-05-01

    We present multi-wavelength radio observations with the Very Large Array, and narrow- and broad-band optical observations with the 2.5-m telescope at the Las Campanas Observatory, of a well-defined sample of high-luminosity Fanaroff-Riley class II radio galaxies and quasars, selected from the Molonglo Reference Catalogue 1-Jy sample. These observations were carried out as part of a programme to investigate the effects of orientation and environment on some of the observed properties of these sources. We examine the dependence of the Liu-Pooley relationship, which shows that radio lobes with flatter radio spectra are less depolarized, on size, identification and redshift, and show that it is significantly stronger for smaller sources, with the strength of the relationship being similar for both radio galaxies and quasars. In addition to Doppler effects, there appear to be intrinsic differences between the lobes on opposite sides. We discuss the asymmetry in brightness and location of the hotspots, and present estimates of the ages and velocities from matched-resolution observations in the L and C bands. Narrow- and broad-band optical images of some of these sources were made to study their environments and correlate with the symmetry parameters. An extended emission-line region is seen in a quasar, and in four of the objects possible companion galaxies are seen close to the radio axis.

  6. Dual-Source Swept-Source Optical Coherence Tomography Reconstructed on Integrated Spectrum

    Directory of Open Access Journals (Sweden)

    Shoude Chang

    2012-01-01

    Full Text Available Dual-source swept-source optical coherence tomography (DS-SSOCT has two individual sources with different central wavelengths, linewidth, and bandwidths. Because of the difference between the two sources, the individually reconstructed tomograms from each source have different aspect ratio, which makes the comparison and integration difficult. We report a method to merge two sets of DS-SSOCT raw data in a common spectrum, on which both data have the same spectrum density and a correct separation. The reconstructed tomographic image can seamlessly integrate the two bands of OCT data together. The final image has higher axial resolution and richer spectroscopic information than any of the individually reconstructed tomography image.

  7. Planets as background noise sources in free space optical communications

    Science.gov (United States)

    Katz, J.

    1986-01-01

    Background noise generated by planets is the dominant noise source in most deep space direct detection optical communications systems. Earlier approximate analyses of this problem are based on simplified blackbody calculations and can yield results that may be inaccurate by up to an order of magnitude. Various other factors that need to be taken into consideration, such as the phase angle and the actual spectral dependence of the planet albedo, in order to obtain a more accurate estimate of the noise magnitude are examined.

  8. Glow discharge lamp: a light source for optical emission spectroscopy

    International Nuclear Information System (INIS)

    Vishwanathan, K.S.; Srinivasan, V.; Nalini, S.; Mahalingam, T.R.

    1990-01-01

    A glow discharge lamp based on a modified version of the Grimm design has been fabricated. Its utility as a radiation source for optical emmission spectrography by standardising a method for the analysis of low alloy steels using a set of certified standards from DMRL, Hyderabad, has been demonstrated. A model has been proposed where the sputtering rates of different metals have been correlated with their heats of sublimation, metallic radii and densities. Sputtering rates of ten different metals obtained from literature have been used to test this model, and the correlation appears to be excellent. (author). 19 re fs., 13 figs., 2 tabs

  9. Configuration of electro-optic fire source detection system

    Science.gov (United States)

    Fabian, Ram Z.; Steiner, Zeev; Hofman, Nir

    2007-04-01

    The recent fighting activities in various parts of the world have highlighted the need for accurate fire source detection on one hand and fast "sensor to shooter cycle" capabilities on the other. Both needs can be met by the SPOTLITE system which dramatically enhances the capability to rapidly engage hostile fire source with a minimum of casualties to friendly force and to innocent bystanders. Modular system design enable to meet each customer specific requirements and enable excellent future growth and upgrade potential. The design and built of a fire source detection system is governed by sets of requirements issued by the operators. This can be translated into the following design criteria: I) Long range, fast and accurate fire source detection capability. II) Different threat detection and classification capability. III) Threat investigation capability. IV) Fire source data distribution capability (Location, direction, video image, voice). V) Men portability. ) In order to meet these design criteria, an optimized concept was presented and exercised for the SPOTLITE system. Three major modular components were defined: I) Electro Optical Unit -Including FLIR camera, CCD camera, Laser Range Finder and Marker II) Electronic Unit -including system computer and electronic. III) Controller Station Unit - Including the HMI of the system. This article discusses the system's components definition and optimization processes, and also show how SPOTLITE designers successfully managed to introduce excellent solutions for other system parameters.

  10. Development of optical spectrum acquisition with spectrophotometer for characterization of optical radiation sources

    International Nuclear Information System (INIS)

    Solano Vargas, Alvaro

    2013-01-01

    An improved process of the data acquisition system is developed with Pasco 750 interface and Pasco OS-8539 spectrophotometer. The optical spectrum and color temperature of incandescent sources available are obtained from the Laboratorio de Fotonica y Tecnologia Laser Aplicada. The procedures developed in the project are recommended to collect data and analyze results. The purchase of a new Software and the interface of Pasco is recommended to have a better operation and update [es

  11. All fiber optics circular-state swept source polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Lin, Hermann; Kao, Meng-Chun; Lai, Chih-Ming; Huang, Jyun-Cin; Kuo, Wen-Chuan

    2014-02-01

    A swept source (SS)-based circular-state (CS) polarization-sensitive optical coherence tomography (PS-OCT) constructed entirely with polarization-maintaining fiber optics components is proposed with the experimental verification. By means of the proposed calibration scheme, bulk quarter-wave plates can be replaced by fiber optics polarization controllers to, therefore, realize an all-fiber optics CS SSPS-OCT. We also present a numerical dispersion compensation method, which can not only enhance the axial resolution, but also improve the signal-to-noise ratio of the images. We demonstrate that this compact and portable CS SSPS-OCT system with an accuracy comparable to bulk optics systems requires less stringent lens alignment and can possibly serve as a technology to realize PS-OCT instrument for clinical applications (e.g., endoscopy). The largest deviations in the phase retardation (PR) and fast-axis (FA) angle due to sample probe in the linear scanning and a rotation angle smaller than 65 deg were of the same order as those in stationary probe setups. The influence of fiber bending on the measured PR and FA is also investigated. The largest deviations of the PR were 3.5 deg and the measured FA change by ~12 to 21 deg. Finally, in vivo imaging of the human fingertip and nail was successfully demonstrated with a linear scanning probe.

  12. IDENTIFICATIONS OF FIVE INTEGRAL SOURCES VIA OPTICAL SPECTROSCOPY

    International Nuclear Information System (INIS)

    Butler, Suzanne C.; Tomsick, John A.; Chaty, Sylvain; Heras, Juan A. Zurita; Rodriguez, Jerome; Walter, Roland; Kaaret, Philip; Kalemci, Emrah; Oezbey, Mehtap

    2009-01-01

    The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is discovering hundreds of new hard X-ray sources, many of which remain unidentified. We report on optical spectroscopy of five such sources for which X-ray observations at lower energies (∼0.5-10 keV) and higher angular resolutions than INTEGRAL have allowed for unique optical counterparts to be located. We find that INTEGRAL Gamma-Ray (IGR) J16426+6536 and IGR J22292+6647 are Type 1 Seyfert active galactic nuclei (with IGR J16426+6536 further classified as a Seyfert 1.5) which have redshifts of z = 0.323 and z = 0.113, respectively. IGR J18308-1232 is identified as a cataclysmic variable (CV), and we confirm a previous identification of IGR J19267+1325 as a magnetic CV. IGR J18214-1318 is identified as an obscured high-mass X-ray binary (HMXB), which are systems thought to have a compact object embedded in the stellar wind of a massive star. We combine Chandra fluxes with distances based on the optical observations to calculate X-ray luminosities of the HMXB and CVs, finding L 0.3-10keV = 5 x 10 36 erg s -1 for IGR J18214-1318, L 0.3-10keV = 1.3 x 10 32 erg s -1 for IGR J18308-1232, and L 0.3-10keV = 6.7 x 10 32 erg s -1 for IGR J19267+1325.

  13. Fast optical source for quantum key distribution based on semiconductor optical amplifiers.

    Science.gov (United States)

    Jofre, M; Gardelein, A; Anzolin, G; Amaya, W; Capmany, J; Ursin, R; Peñate, L; Lopez, D; San Juan, J L; Carrasco, J A; Garcia, F; Torcal-Milla, F J; Sanchez-Brea, L M; Bernabeu, E; Perdigues, J M; Jennewein, T; Torres, J P; Mitchell, M W; Pruneri, V

    2011-02-28

    A novel integrated optical source capable of emitting faint pulses with different polarization states and with different intensity levels at 100 MHz has been developed. The source relies on a single laser diode followed by four semiconductor optical amplifiers and thin film polarizers, connected through a fiber network. The use of a single laser ensures high level of indistinguishability in time and spectrum of the pulses for the four different polarizations and three different levels of intensity. The applicability of the source is demonstrated in the lab through a free space quantum key distribution experiment which makes use of the decoy state BB84 protocol. We achieved a lower bound secure key rate of the order of 3.64 Mbps and a quantum bit error ratio as low as 1.14×10⁻² while the lower bound secure key rate became 187 bps for an equivalent attenuation of 35 dB. To our knowledge, this is the fastest polarization encoded QKD system which has been reported so far. The performance, reduced size, low power consumption and the fact that the components used can be space qualified make the source particularly suitable for secure satellite communication.

  14. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lu Zenghai; Kasaragod, Deepa K; Matcher, Stephen J, E-mail: z.lu@sheffield.ac.uk, E-mail: s.j.matcher@sheffield.ac.uk [Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ (United Kingdom)

    2011-02-21

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincare sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  15. Optic axis determination by fibre-based polarization-sensitive swept-source optical coherence tomography

    International Nuclear Information System (INIS)

    Lu Zenghai; Kasaragod, Deepa K; Matcher, Stephen J

    2011-01-01

    We describe a fibre-based variable-incidence angle (VIA) polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) system to determine the 3D optical axis of birefringent biological tissues. Single-plane VIA-PS-OCT is also explored which requires measurement of the absolute fast-axis orientation. A state-of-the-art PS-SS-OCT system with some improvements both in hardware and software was used to determine the apparent optical birefringence of equine tendon for a number of different illumination directions. Polar and azimuthal angles of cut equine tendon were produced by the VIA method and compared with the nominal values. A quarter waveplate (QWP) and equine tendon were used as test targets to validate the fast-axis measurements using the system. Polar and azimuthal angles of cut equine tendon broadly agreed with the expected values within about 8% of the nominal values. A theoretical and experimental analysis of the effect of the sample arm fibre on determination of optical axis orientation using a proposed definition based on the orientation of the eigenpolarization ellipse experimentally confirms that this algorithm only works correctly for special settings of the sample arm fibre. A proposed algorithm based on the angle between Stokes vectors on the Poincare sphere is confirmed to work for all settings of the sample arm fibre. A calibration procedure is proposed to remove the sign ambiguity of the measured orientation and was confirmed experimentally by using the QWP.

  16. Assessing embryo development using swept source optical coherence tomography

    Science.gov (United States)

    Caujolle, S.; Cernat, R.; Silvestri, G.; Marques, M. J.; Bradu, A.; Feuchter, T.; Robinson, G.; Griffin, D.; Podoleanu, A.

    2018-03-01

    A detailed assessment of embryo development would assist biologists with selecting the most suitable embryos for transfer leading to higher pregnancy rates. Currently, only low resolution microscopy is employed to perform this assessment. Although this method delivers some information on the embryo surface morphology, no specific details are shown related to its inner structure. Using a Master-Slave Swept-Source Optical Coherence Tomography (SS-OCT), images of bovine embryos from day 7 after fertilization were collected from different depths. The dynamic changes inside the embryos were examined, in detail and in real-time from several depths. To prove our ability to characterize the morphology, a single embryo was imaged over 26 hours. The embryo was deprived of its life support environment, leading to its death. Over this period, clear morphological changes were observed.

  17. Optics of relativistic sources in a spherically symmetric gravitational field

    International Nuclear Information System (INIS)

    Campbell, G.A.

    1975-01-01

    The effects of spectral shifts and gravitational focussing on radiation from sources moving geodesically in the Schwarzschild gravitational field is analyzed using the general-relativistic equations for geodesic motion and for the propagation of radiation along null geodesics in the geometrical optics approximation. The exact solutions of the Schwarzschild geodesic equations are briefly discussed for the null and time-like cases, and the method of classifying the orbital types of motion based on the effective radial potential is presented. A method of finding the stability of these orbits using this technique is discussed. The geometrical optics approximation for the propagation of radiation is discussed, and the area-intensity law for the Schwarzschild field is derived. The particularly interesting region near R = 3m is investigated by means of expansions of the exact equations. Numerical techniques for calculating radiation patterns from the propagation equations are discussed, including techniques for obtaining the time variation along geodesics and differences in propagation time along different null geodesics. Finally, the implications of these calculations for the apparent contradiction in energy requirements set by Joseph Weber's observations of galactic gravitational radiation and by astronomical observation are discussed. (Diss. Abstr. Int., B)

  18. Pure sources and efficient detectors for optical quantum information processing

    Science.gov (United States)

    Zielnicki, Kevin

    Over the last sixty years, classical information theory has revolutionized the understanding of the nature of information, and how it can be quantified and manipulated. Quantum information processing extends these lessons to quantum systems, where the properties of intrinsic uncertainty and entanglement fundamentally defy classical explanation. This growing field has many potential applications, including computing, cryptography, communication, and metrology. As inherently mobile quantum particles, photons are likely to play an important role in any mature large-scale quantum information processing system. However, the available methods for producing and detecting complex multi-photon states place practical limits on the feasibility of sophisticated optical quantum information processing experiments. In a typical quantum information protocol, a source first produces an interesting or useful quantum state (or set of states), perhaps involving superposition or entanglement. Then, some manipulations are performed on this state, perhaps involving quantum logic gates which further manipulate or entangle the intial state. Finally, the state must be detected, obtaining some desired measurement result, e.g., for secure communication or computationally efficient factoring. The work presented here concerns the first and last stages of this process as they relate to photons: sources and detectors. Our work on sources is based on the need for optimized non-classical states of light delivered at high rates, particularly of single photons in a pure quantum state. We seek to better understand the properties of spontaneous parameteric downconversion (SPDC) sources of photon pairs, and in doing so, produce such an optimized source. We report an SPDC source which produces pure heralded single photons with little or no spectral filtering, allowing a significant rate enhancement. Our work on detectors is based on the need to reliably measure single-photon states. We have focused on

  19. Centralized light-source optical access network based on polarization multiplexing.

    Science.gov (United States)

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2010-03-01

    This paper presents and demonstrates a centralized light source optical access network based on optical polarization multiplexing technique. By using two optical sources emitting light orthogonally polarized in the Central Node for downstream and upstream operations, the Remote Node is kept source-free. EVM values below telecommunication standard requirements have been measured experimentally when bidirectional digital signals have been transmitted over 10 km of SMF employing subcarrier multiplexing technique in the electrical domain.

  20. Swept-Source Optical Coherence Tomographic Findings of Choroidal Osteoma

    Directory of Open Access Journals (Sweden)

    Yuki Hayashi

    2014-07-01

    Full Text Available Purpose: To report the morphologic features of a choroidal osteoma using swept-source optical coherence tomography (SS-OCT and fundus autofluorescence (FAF. Methods: Two eyes of two cases with a choroidal osteoma were studied using SS-OCT and FAF. Results: The location of the tumor was circumpapillary without macular involvement in case 1 and juxtapapillary with macular involvement in case 2. Both cases had a mixture of calcified and decalcified areas, and a concomitant choroidal neovascularization was found in case 2. The FAF images showed decreased autofluorescence in the central decalcified regions and relatively preserved fluorescence in marginal calcified regions in both cases. SS-OCT revealed a normal inner retina and an abnormal outer retina in both cases, and subretinal fluid in case 2. The calcified regions appeared sponge-like and were multilayered in case 2. A lamellar reflective pattern was observed in the decalcified regions in case 1, and hyperreflective mound-like areas were observed in both cases. SS-OCT demonstrated hyperreflective areas above Bruch's membrane accompanied by disruption of Bruch's membrane in case 1. The chorioscleral border was visible in both cases. Conclusions: The FAF pattern in the calcified and decalcified areas of the choroidal osteoma may correspond to the different stage of tumor evolution. The SS-OCT findings indicate that choroidal osteomas can have characteristic reflective patterns and alterations of the overlying retina.

  1. Optically pumped polarized 23Na vapor target for use in polarized ion source. Technical progress report

    International Nuclear Information System (INIS)

    Anderson, L.W.

    1984-01-01

    We are currently measuring relaxation times in an optically pumped 23 Na vapor target. Our research is directed toward improvements in the optically pumped Na vapor targets used for the production of polarized H - ions. In this progress report we review the properties of the optically pumped polarized H - ion source and especially the optically pumped Na vapor target employed in this source as well as discussing the progress of our research on relaxation times in an optically pumped Na vapor target. 30 references, 6 figures, 3 tables

  2. Chiral Topological Orders in an Optical Raman Lattice (Open Source)

    Science.gov (United States)

    2016-03-01

    PAPER • OPEN ACCESS Chiral topological orders in an optical Raman lattice To cite this article: Xiong-Jun Liu et al 2016 New J. Phys. 18...... chiral spin liquid Abstract Wefind an optical Raman lattice without spin-orbit coupling showing chiral topological orders for cold atoms. Two

  3. Fire Source Localization Based on Distributed Temperature Sensing by a Dual-Line Optical Fiber System.

    Science.gov (United States)

    Sun, Miao; Tang, Yuquan; Yang, Shuang; Li, Jun; Sigrist, Markus W; Dong, Fengzhong

    2016-06-06

    We propose a method for localizing a fire source using an optical fiber distributed temperature sensor system. A section of two parallel optical fibers employed as the sensing element is installed near the ceiling of a closed room in which the fire source is located. By measuring the temperature of hot air flows, the problem of three-dimensional fire source localization is transformed to two dimensions. The method of the source location is verified with experiments using burning alcohol as fire source, and it is demonstrated that the method represents a robust and reliable technique for localizing a fire source also for long sensing ranges.

  4. Fire Source Localization Based on Distributed Temperature Sensing by a Dual-Line Optical Fiber System

    Directory of Open Access Journals (Sweden)

    Miao Sun

    2016-06-01

    Full Text Available We propose a method for localizing a fire source using an optical fiber distributed temperature sensor system. A section of two parallel optical fibers employed as the sensing element is installed near the ceiling of a closed room in which the fire source is located. By measuring the temperature of hot air flows, the problem of three-dimensional fire source localization is transformed to two dimensions. The method of the source location is verified with experiments using burning alcohol as fire source, and it is demonstrated that the method represents a robust and reliable technique for localizing a fire source also for long sensing ranges.

  5. Linking optical and infrared observations with gravitational wave sources through transient variability

    International Nuclear Information System (INIS)

    Stubbs, C W

    2008-01-01

    Optical and infrared observations have thus far detected more celestial cataclysms than have been seen in gravity waves (GW). This argues that we should search for gravity wave signatures that correspond to transient variables seen at optical wavelengths, at precisely known positions. There is an unknown time delay between the optical and gravitational transient, but knowing the source location precisely specifies the corresponding time delays across the gravitational antenna network as a function of the GW-to-optical arrival time difference. Optical searches should detect virtually all supernovae that are plausible gravitational radiation sources. The transient optical signature expected from merging compact objects is not as well understood, but there are good reasons to expect detectable transient optical/IR emission from most of these sources as well. The next generation of deep wide-field surveys (for example PanSTARRS and LSST) will be sensitive to subtle optical variability, but we need to fill the 'blind spots' that exist in the galactic plane, and for optically bright transient sources. In particular, a galactic plane variability survey at λ∼ 2 μm seems worthwhile. Science would benefit from closer coordination between the various optical survey projects and the gravity wave community

  6. Depth-of-field effects in wiggler radiation sources: Geometrical versus wave optics

    Directory of Open Access Journals (Sweden)

    Richard P. Walker

    2017-02-01

    Full Text Available A detailed analysis is carried out of the optical properties of synchrotron radiation emitted by multipole wigglers, concentrating on the effective source size and brightness and the so-called “depth of field” effects, concerning which there has been some controversy in the literature. By comparing calculations made with both geometrical optics and wave optics methods we demonstrate that the two approaches are not at variance, and that the wave optics results tend towards those of geometrical optics under well-defined conditions.

  7. Design and simulation of ion optics for ion sources for production of singly charged ions

    Science.gov (United States)

    Zelenak, A.; Bogomolov, S. L.

    2004-05-01

    During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments.

  8. Design and simulation of ion optics for ion sources for production of singly charged ions

    International Nuclear Information System (INIS)

    Zelenak, A.; Bogomolov, S.L.

    2004-01-01

    During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments

  9. Miniature x-ray point source for alignment and calibration of x-ray optics

    International Nuclear Information System (INIS)

    Price, R.H.; Boyle, M.J.; Glaros, S.S.

    1977-01-01

    A miniature x-ray point source of high brightness similar to that of Rovinsky, et al. is described. One version of the x-ray source is used to align the x-ray optics on the Argus and Shiva laser systems. A second version is used to determine the spatial and spectral transmission functions of the x-ray optics. The spatial and spectral characteristics of the x-ray emission from the x-ray point source are described. The physical constraints including size, intensity and thermal limitations, and useful lifetime are discussed. The alignment and calibration techniques for various x-ray optics and detector combinations are described

  10. Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter

    Science.gov (United States)

    Tsai, Tsung-Han; Ahsen, Osman O.; Lee, Hsiang-Chieh; Liang, Kaicheng; Giacomelli, Michael G.; Potsaid, Benjamin M.; Tao, Yuankai K.; Jayaraman, Vijaysekhar; Kraus, Martin F.; Hornegger, Joachim; Figueiredo, Marisa; Huang, Qin; Mashimo, Hiroshi; Cable, Alex E.; Fujimoto, James G.

    2014-03-01

    We developed an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor based imaging catheter, which provided an imaging speed of 600 kHz axial scan rate and 8 μm axial resolution in tissue. The micromotor catheter was 3.2 mm in diameter and could be introduced through the 3.7 mm accessory port of an endoscope. Imaging was performed at 400 frames per second with an 8 μm spot size using a pullback to generate volumetric data over 16 mm with a pixel spacing of 5 μm in the longitudinal direction. Three-dimensional OCT (3D-OCT) imaging was performed in patients with a cross section of pathologies undergoing standard upper and lower endoscopy at the Veterans Affairs Boston Healthcare System (VABHS). Patients with Barrett's esophagus, dysplasia, and inflammatory bowel disease were imaged. The use of distally actuated imaging catheters allowed OCT imaging with more flexibility such as volumetric imaging in the terminal ileum and the assessment of the hiatal hernia using retroflex imaging. The high rotational stability of the micromotor enabled 3D volumetric imaging with micron scale volumetric accuracy for both en face and cross-sectional imaging. The ability to perform 3D OCT imaging in the GI tract with microscopic accuracy should enable a wide range of studies to investigate the ability of OCT to detect pathology as well as assess treatment response.

  11. Tunable optical frequency comb enabled scalable and cost-effective multiuser orthogonal frequency-division multiple access passive optical network with source-free optical network units.

    Science.gov (United States)

    Chen, Chen; Zhang, Chongfu; Liu, Deming; Qiu, Kun; Liu, Shuang

    2012-10-01

    We propose and experimentally demonstrate a multiuser orthogonal frequency-division multiple access passive optical network (OFDMA-PON) with source-free optical network units (ONUs), enabled by tunable optical frequency comb generation technology. By cascading a phase modulator (PM) and an intensity modulator and dynamically controlling the peak-to-peak voltage of a PM driven signal, a tunable optical frequency comb source can be generated. It is utilized to assist the configuration of a multiple source-free ONUs enhanced OFDMA-PON where simultaneous and interference-free multiuser upstream transmission over a single wavelength can be efficiently supported. The proposed multiuser OFDMA-PON is scalable and cost effective, and its feasibility is successfully verified by experiment.

  12. Linac Coherent Light Source soft x-ray materials science instrument optical design and monochromator commissioning

    Czech Academy of Sciences Publication Activity Database

    Heimann, P.; Krupin, O.; Schlotter, W.F.; Turner, J.; Krzywinski, J.; Sorgenfrei, F.; Messerschmidt, M.; Bernstein, D.; Chalupský, Jaromír; Hájková, Věra; Hau-Riege, S.; Holmes, M.; Juha, Libor; Kelez, N.; Lüning, J.; Nordlund, D.; Perea, M.F.; Scherz, A.; Soufli, R.; Wurth, W.; Rowen, M.

    2011-01-01

    Roč. 82, č. 9 (2011), 093104/1-093104/8 ISSN 0034-6748 R&D Projects: GA MŠk(CZ) ME10046 Institutional research plan: CEZ:AV0Z10100523 Keywords : diffraction gratings * light sources * linear accelerators * optical materials * x-ray monochromators * x-ray optics Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.367, year: 2011

  13. A simple optical spectral calibration technique for pulsed THz sources

    NARCIS (Netherlands)

    Wijnen, F.J.P.; G. Berden,; Jongma, R.T.

    2010-01-01

    We have quantified the sensitivity of a simple method to measurethe frequency spectrum of pulsed terahertz (THz) radiation. The THzpulses are upconverted to the optical regime by sideband generation in a zinctelluride (ZnTe) crystal using a continuous wave (cw) narrow-bandwidthnear-infrared laser. A

  14. Stechiometric neodymium compounds as new materials for light sources in integrated optics

    International Nuclear Information System (INIS)

    Malinowski, M.

    1981-01-01

    Short review of physico-chemical properties of stechiometric neodymium compounds has been presented. Several constructions of minilasers as promising light sources for integrated optics devices have been described. (author)

  15. Optical and near-infrared imaging of faint Gigahertz Peaked Spectrum sources

    NARCIS (Netherlands)

    Snellen, IAG; Schilizzi, RT; de Bruyn, AG; Miley, GK; Rottgering, HJA; McMahon, RG; Fournon, IP

    1998-01-01

    A sample of 47 faint Gigahertz Peaked Spectrum (GPS) radio sources selected from the Westerbork Northern Sky Survey (WENSS) has been imaged in the optical and near-infrared, resulting in an identification fraction of 87 per cent. The R - I and R - K colours of the faint optical counterparts are as

  16. Interference contrast in multi-source few photon optics

    OpenAIRE

    Laskowski, Wieslaw; Wiesniak, Marcin; Zukowski, Marek; Bourennane, Mohamed; Weinfurter, Harald

    2009-01-01

    Many recent experiments employ several parametric down conversion (PDC) sources to get multiphoton interference. Such interference has applications in quantum information. We study here how effects due to photon statistics, misalignment, and partial distinguishability of the PDC pairs originating from different sources may lower the interference contrast in the multiphoton experiments.

  17. Optical synchronization system for femtosecond X-ray sources

    Science.gov (United States)

    Wilcox, Russell B [El Cerrito, CA; Holzwarth, Ronald [Munich, DE

    2011-12-13

    Femtosecond pump/probe experiments using short X-Ray and optical pulses require precise synchronization between 100 meter-10 km separated lasers in a various experiments. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1-10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with various implementations. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range two single-frequency lasers separated by several teraHertz will be lock to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes.

  18. Optical Synchronization Systems for Femtosecond X-raySources

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, Russell; Staples, John W.; Holzwarth, Ronald

    2004-05-09

    In femtosecond pump/probe experiments using short X-Ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error over 100 meter of glass fiber. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1 10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with a piezoelectric phase modulator. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range we will lock two single-frequency lasers separated by several tera Hertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes.

  19. Optical Synchronization Systems for Femtosecond X-ray Sources

    International Nuclear Information System (INIS)

    Wilcox, Russell; Staples, John W.; Holzwarth, Ronald

    2004-01-01

    In femtosecond pump/probe experiments using short X-Ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error over 100 meter of glass fiber. For stabilization in the hundred femtosecond range a CW laser is amplitude modulated at 1 10 GHz, the signal retroreflected from the far end, and the relative phase used to correct the transit time with a piezoelectric phase modulator. For the sub-10 fsec range the laser frequency itself is upshifted 55 MHz with an acousto-optical modulator, retroreflected, upshifted again and phase compared at the sending end to a 110 MHz reference. Initial experiments indicate less than 1 fsec timing jitter. To lock lasers in the sub-10 fs range we will lock two single-frequency lasers separated by several tera Hertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes

  20. Optical technologies for extreme-ultraviolet and soft X-ray coherent sources

    International Nuclear Information System (INIS)

    Canova, Federico; Poletto, Luca

    2015-01-01

    The book reviews the most recent achievements in optical technologies for XUV and X-ray coherent sources. Particular attention is given to free-electron-laser facilities, but also to other sources available at present, such as synchrotrons, high-order laser harmonics and X-ray lasers. The optical technologies relevant to each type of source are discussed. In addition, the main technologies used for photon handling and conditioning, namely multilayer mirrors, adaptive optics, crystals and gratings are explained. Experiments using coherent light received during the last decades a lot of attention for the X-ray regime. Strong efforts were taken for the realization of almost fully coherent sources, e.g. the free-electron lasers, both as independent sources in the femtosecond and attosecond regimes and as seeding sources for free-electron-lasers and X-ray gas lasers. In parallel to the development of sources, optical technologies for photon handling and conditioning of such coherent and intense X-ray beams advanced. New problems were faced for the realization of optical components of beamlines demanding to manage coherent X-ray photons, e.g. the preservation of coherence and time structure of ultra short pulses.

  1. Miniaturized pulsed laser source for time-domain diffuse optics routes to wearable devices.

    Science.gov (United States)

    Di Sieno, Laura; Nissinen, Jan; Hallman, Lauri; Martinenghi, Edoardo; Contini, Davide; Pifferi, Antonio; Kostamovaara, Juha; Mora, Alberto Dalla

    2017-08-01

    We validate a miniaturized pulsed laser source for use in time-domain (TD) diffuse optics, following rigorous and shared protocols for performance assessment of this class of devices. This compact source (12×6  mm2) has been previously developed for range finding applications and is able to provide short, high energy (∼100  ps, ∼0.5  nJ) optical pulses at up to 1 MHz repetition rate. Here, we start with a basic level laser characterization with an analysis of suitability of this laser for the diffuse optics application. Then, we present a TD optical system using this source and its performances in both recovering optical properties of tissue-mimicking homogeneous phantoms and in detecting localized absorption perturbations. Finally, as a proof of concept of in vivo application, we demonstrate that the system is able to detect hemodynamic changes occurring in the arm of healthy volunteers during a venous occlusion. Squeezing the laser source in a small footprint removes a key technological bottleneck that has hampered so far the realization of a miniaturized TD diffuse optics system, able to compete with already assessed continuous-wave devices in terms of size and cost, but with wider performance potentialities, as demonstrated by research over the last two decades. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  2. Optical identifications of IRAS point sources: the Fornax, Hydra I and Coma clusters

    International Nuclear Information System (INIS)

    Wang, G.; Leggett, S.K.; Savage, A.

    1991-01-01

    We present optical identifications for 66 IRAS point sources in the region of the Fornax cluster of galaxies, 106 IRAS point sources in the region of the Hydra I cluster of galaxies (Abell 1060) and 59 IRAS point sources in the region of the Coma cluster of galaxies (Abell 1656). Eight other sources in Hydra I do not have optical counterparts and are very probably due to infrared cirrus. Twenty-three (35 per cent) of the Fornax sources are associated with stars and 43 (65 per cent) with galaxies; 48 (42 per cent) of the Hydra I sources are associated with stars and 58 (51 per cent) with galaxies; 18 (31 per cent) of the Coma sources are associated with stars and 41 (69 per cent) with galaxies. The stellar and infrared cirrus surface density is consistent with the galactic latitude of each field. (author)

  3. Waveguide Cavity Resonator as a Source of Optical Squeezing

    Science.gov (United States)

    Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.

    2017-04-01

    We present the generation of continuous-wave optical squeezing from a titanium-in-diffused lithium niobate waveguide resonator. We directly measure 2.9 ±0.1 dB of single-mode squeezing, which equates to a produced level of 4.9 ±0.1 dB after accounting for detection losses. This device showcases the current capabilities of this waveguide architecture and precipitates more complicated integrated continuous-wave quantum devices in the continuous-variable regime.

  4. Optical Synchronization Systems for Femtosecond X-Ray Sources

    CERN Document Server

    Wilcox, Russell; Staples, John W

    2005-01-01

    In femtosecond pump/probe experiments using short x-ray and optical pulses, precise synchronization must be maintained between widely separated lasers in a synchrotron or FEL facility. We are developing synchronization systems using optical signals for applications requiring different ranges of timing error. For the sub-100fs range we use an amplitude modulated CW laser at 1GHz to transmit RF phase information, and control the delay through a 100m fiber by observing the retroreflected signal. Initial results show 40fs peak-to-peak error above 10Hz, and 200fs long term drift, mainly due to amplitude sensitivity in the analog mixers. For the sub-10fs range we will lock two single-frequency lasers separated by several teraHertz to a master modelocked fiber laser, transmit the two frequencies over fiber, and lock two comb lines of a slave laser to these frequencies, thus synchronizing the two modelocked laser envelopes. For attosecond synchronization we propose a stabilized, free space link using bulk lens wavegu...

  5. Optical emission spectroscopy of carbon laser plasma ion source

    Science.gov (United States)

    Balki, Oguzhan; Rahman, Md. Mahmudur; Elsayed-Ali, Hani E.

    2018-04-01

    Carbon laser plasma generated by an Nd:YAG laser (wavelength 1064 nm, pulse width 7 ns, fluence 4-52 J cm-2) is studied by optical emission spectroscopy and ion time-of-flight. Up to C4+ ions are detected with the ion flux strongly dependent on the laser fluence. The increase in ion charge with the laser fluence is accompanied by observation of multicharged ion lines in the optical spectra. The time-integrated electron temperature Te is calculated from the Boltzmann plot using the C II lines at 392.0, 426.7, and 588.9 nm. Te is found to increase from ∼0.83 eV for a laser fluence of 22 J cm-2 to ∼0.90 eV for 40 J cm-2. The electron density ne is obtained from the Stark broadened profiles of the C II line at 392 nm and is found to increase from ∼ 2 . 1 × 1017cm-3 for 4 J cm-2 to ∼ 3 . 5 × 1017cm-3 for 40 J cm-2. Applying an external electric field parallel to the expanding plume shows no effect on the line emission intensities. Deconvolution of ion time-of-flight signal with a shifted Maxwell-Boltzmann distribution for each charge state results in an ion temperature Ti ∼4.7 and ∼6.0 eV for 20 and 36 J cm-2, respectively.

  6. Rate equation modelling of the optically pumped spin-exchange source

    International Nuclear Information System (INIS)

    Stenger, J.; Rith, K.

    1995-01-01

    Sources for spin polarized hydrogen or deuterium, polarized via spin-exchange of a laser optically pumped alkali metal, can be modelled by rate equations. The rate equations for this type of source, operated either with hydrogen or deuterium, are given explicitly with the intention of providing a useful tool for further source optimization and understanding. Laser optical pumping of alkali metal, spin-exchange collisions of hydrogen or deuterium atoms with each other and with alkali metal atoms are included, as well as depolarization due to flow and wall collisions. (orig.)

  7. DFB fiber laser as source for optical communication systems

    DEFF Research Database (Denmark)

    Varming, Poul; Hübner, Jörg; Kristensen, Martin

    1997-01-01

    The results demonstrate that DFB fiber lasers are an attractive alternative as sources in telecommunication systems. The lasers show excellent long-term stability with very high signal to noise ratio and a reasonable output power, combined with exceptional temperature stability and inherent fiber...

  8. Simple and versatile long range swept source for optical coherence tomography applications

    International Nuclear Information System (INIS)

    Bräuer, Bastian; Lippok, Norman; Murdoch, Stuart G; Vanholsbeeck, Frédérique

    2015-01-01

    We present a versatile long coherence length swept-source laser design for optical coherence tomography applications. This design consists of a polygonal spinning mirror and an optical gain chip in a modified Littman–Metcalf cavity. A narrowband intra-cavity filter is implemented through multiple passes off a diffraction grating set at grazing incidence. The key advantage of this design is that it can be readily adapted to any wavelength regions for which broadband gain chips are available. We demonstrate this by implementing sources at 1650 nm, 1550 nm, 1310 nm and 1050 nm. In particular, we present a 1310 nm swept source laser with 24 mm coherence length, 95 nm optical bandwidth, 2 kHz maximum sweep frequency and 7.5 mW average output power. These parameters make it a suitable source for the imaging of biological samples. (paper)

  9. Initial operating experience and recent development on the TRIUMF optically pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Schmor, P.W.; Law, W.M.; Levy, C.D.P.; McDonald, M.

    1988-01-01

    A polarized H - ion source using optical pumping techniques has been developed at TRIUMF. This source was used to demonstrate (on an ion source test stand) the feasibility of producing 10- μA of ∼ 60% polarized H - ion beam in a dc mode suitable for injection into the TRIUMF cyclotron. The source has been installed in a 300 kV high voltage terminal connected to the cyclotron via a recently constructed beam transport line. A polarization of 80% is anticipated near the end of 1988 after the installation of a superconducting solenoid to the source. In this paper the authors describe the initial operating experience, recent developments, and the future plans for the TRIUMF optically pumped polarized ion source

  10. Particle damage sources for fused silica optics and their mitigation on high energy laser systems.

    Science.gov (United States)

    Bude, J; Carr, C W; Miller, P E; Parham, T; Whitman, P; Monticelli, M; Raman, R; Cross, D; Welday, B; Ravizza, F; Suratwala, T; Davis, J; Fischer, M; Hawley, R; Lee, H; Matthews, M; Norton, M; Nostrand, M; VanBlarcom, D; Sommer, S

    2017-05-15

    High energy laser systems are ultimately limited by laser-induced damage to their critical components. This is especially true of damage to critical fused silica optics, which grows rapidly upon exposure to additional laser pulses. Much progress has been made in eliminating damage precursors in as-processed fused silica optics (the advanced mitigation process, AMP3), and very high damage resistance has been demonstrated in laboratory studies. However, the full potential of these improvements has not yet been realized in actual laser systems. In this work, we explore the importance of additional damage sources-in particular, particle contamination-for fused silica optics fielded in a high-performance laser environment, the National Ignition Facility (NIF) laser system. We demonstrate that the most dangerous sources of particle contamination in a system-level environment are laser-driven particle sources. In the specific case of the NIF laser, we have identified the two important particle sources which account for nearly all the damage observed on AMP3 optics during full laser operation and present mitigations for these particle sources. Finally, with the elimination of these laser-driven particle sources, we demonstrate essentially damage free operation of AMP3 fused silica for ten large optics (a total of 12,000 cm 2 of beam area) for shots from 8.6 J/cm 2 to 9.5 J/cm 2 of 351 nm light (3 ns Gaussian pulse shapes). Potentially many other pulsed high energy laser systems have similar particle sources, and given the insight provided by this study, their identification and elimination should be possible. The mitigations demonstrated here are currently being employed for all large UV silica optics on the National Ignition Facility.

  11. Conjugation of fiber-coupled wide-band light sources and acousto-optical spectral elements

    Science.gov (United States)

    Machikhin, Alexander; Batshev, Vladislav; Polschikova, Olga; Khokhlov, Demid; Pozhar, Vitold; Gorevoy, Alexey

    2017-12-01

    Endoscopic instrumentation is widely used for diagnostics and surgery. The imaging systems, which provide the hyperspectral information of the tissues accessible by endoscopes, are particularly interesting and promising for in vivo photoluminescence diagnostics and therapy of tumour and inflammatory diseases. To add the spectral imaging feature to standard video endoscopes, we propose to implement acousto-optical (AO) filtration of wide-band illumination of incandescent-lamp-based light sources. To collect maximum light and direct it to the fiber-optic light guide inside the endoscopic probe, we have developed and tested the optical system for coupling the light source, the acousto-optical tunable filter (AOTF) and the light guide. The system is compact and compatible with the standard endoscopic components.

  12. Planar location of the simulative acoustic source based on fiber optic sensor array

    Science.gov (United States)

    Liang, Yi-Jun; Liu, Jun-feng; Zhang, Qiao-ping; Mu, Lin-lin

    2010-06-01

    A fiber optic sensor array which is structured by four Sagnac fiber optic sensors is proposed to detect and locate a simulative source of acoustic emission (AE). The sensing loops of Sagnac interferometer (SI) are regarded as point sensors as their small size. Based on the derived output light intensity expression of SI, the optimum work condition of the Sagnac fiber optic sensor is discussed through the simulation of MATLAB. Four sensors are respectively placed on a steel plate to structure the sensor array and the location algorithms are expatiated. When an impact is generated by an artificial AE source at any position of the plate, the AE signal will be detected by four sensors at different times. With the help of a single chip microcomputer (SCM) which can calculate the position of the AE source and display it on LED, we have implemented an intelligent detection and location.

  13. Quantum Dot Laser for a Light Source of an Athermal Silicon Optical Interposer

    Directory of Open Access Journals (Sweden)

    Nobuaki Hatori

    2015-04-01

    Full Text Available This paper reports a hybrid integrated light source fabricated on a silicon platform using a 1.3 μm wavelength quantum dot array laser. Temperature insensitive characteristics up to 120 °C were achieved by the optimum quantum dot structure and laser structure. Light output power was obtained that was high enough to achieve an optical error-free link of a silicon optical interposer. Furthermore, we investigated a novel spot size convertor in a silicon waveguide suitable for a quantum dot laser for lower energy cost operation of the optical interposer.

  14. A study of ultra-stable optical clocks, frequency sources and standards for space applications

    International Nuclear Information System (INIS)

    Klein, H.A.; Knight, D.J.E.

    1999-01-01

    Optical or laser-based communication systems are expected to supplement microwave based systems for satellite-to-satellite and spacecraft-to-satellite communications early in the next millennium. Optical systems can carry far more traffic than microwave and address the need to increase communication bandwidths to meet the demands of commerce and the entertainment industry. There is already significant research and commercial interest in this area (now driven particularly by the multi-media and Internet services delivery sector) and there is a strong need to establish which are the best choices of optical sources to develop for space based optical communications. In addition to communication requirements there are strong arguments for developing ultra-stable optical frequency sources and detectors in space for at least two other purposes. At present the microwave radiation that is used for communications is also used for other purposes, for example navigation or tracking, and 'space science' experiments. With the switch from the microwave to the optical for communications it may well be convenient to switch to the optical for these and other functions. This study has examined the potential stable laser requirements for a range of space applications. An interim report was presented in the form of a conference paper summarising our initial findings (see Appendix 5). This final report gives our conclusions in more detail and recommends areas for further study

  15. Characterization of tunable light source by optical parametric oscillator for high resolution spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J. W. [Ewha Womens Univ., Seoul (Korea); Rhee, B. G. [Sejong Univ., Seoul (Korea); Park, S. W. [Yonsei Univ., Seoul (Korea); Noh, J. W. [Inha Univ., Incheon (Korea)

    1998-04-01

    A tunable light source is developed by the optical parametric oscillator, which is very useful for a high resolution spectroscopy. The electronic structure of molecules and atoms can be examined by a proper coherent light source. Optical parametric oscillator provides light sources stable and widely tunable. In this work, the characteristics of the parametric optical generation are examined in the LiNbO{sub 3}. The theoretical analysis as well as the experimental measurement is performed. The pump laser is a second harmonic of Nd:YAG laser, and the parametric gain is measured. The characteristics of singly resonant oscillator and doubly resonant oscillator is studied as a function of temperature. It is found that 1mole% MgO:LiNbO{sub 3} crystal provides the tunability from 0.6{mu}m to 3.0{mu}m wavelength. Both the critical and noncritical phase matching are studied. The optical damage occurring in a congruent LiNbO{sub 3} crystal was not observed in 1mole% MgO:LiNbO{sub 3} crystal, opening a possibility for a high power optical parametric oscillation generation. The current work can be extended to an experiment employing the fundamental Nd:YAG as pump to provide a coherent light source for the study of molecular vibrations. 28 refs., 14 figs., 3 tabs. (Author)

  16. VCSEL sources for optical fiber-wireless composite data links at 60GHz

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Pang, Xiaodan; Lebedev, Alexander

    2013-01-01

    This paper presents a performance assessment of 60-GHz mm-wave signal generation using photonic upconversion employing a VCSEL as source. The system reaches 10−9 BER over a variety of optical fibers for data rates of 1.25-Gbit/s.......This paper presents a performance assessment of 60-GHz mm-wave signal generation using photonic upconversion employing a VCSEL as source. The system reaches 10−9 BER over a variety of optical fibers for data rates of 1.25-Gbit/s....

  17. Partial coherence and imperfect optics at a synchrotron radiation source modeled by wavefront propagation

    Science.gov (United States)

    Laundy, David; Alcock, Simon G.; Alianelli, Lucia; Sutter, John P.; Sawhney, Kawal J. S.; Chubar, Oleg

    2014-09-01

    A full wave propagation of X-rays from source to sample at a storage ring beamline requires simulation of the electron beam source and optical elements in the beamline. The finite emittance source causes the appearance of partial coherence in the wave field. Consequently, the wavefront cannot be treated exactly with fully coherent wave propagation or fully incoherent ray tracing. We have used the wavefront code Synchrotron Radiation Workshop (SRW) to perform partially coherent wavefront propagation using a parallel computing cluster at the Diamond Light Source. Measured mirror profiles have been used to correct the wavefront for surface errors.

  18. AN EXAMINATION OF THE OPTICAL SUBSTRUCTURE OF GALAXY CLUSTERS HOSTING RADIO SOURCES

    International Nuclear Information System (INIS)

    Wing, Joshua D.; Blanton, Elizabeth L.

    2013-01-01

    Using radio sources from the Faint Images of the Radio Sky at Twenty-cm survey, and optical counterparts in the Sloan Digital Sky Survey, we have identified a large number of galaxy clusters. The radio sources within these clusters are driven by active galactic nuclei, and our cluster samples include clusters with bent, and straight, double-lobed radio sources. We also included a single-radio-component comparison sample. We examine these galaxy clusters for evidence of optical substructure, testing the possibility that bent double-lobed radio sources are formed as a result of large-scale cluster mergers. We use a suite of substructure analysis tools to determine the location and extent of substructure visible in the optical distribution of cluster galaxies, and compare the rates of substructure in clusters with different types of radio sources. We found no preference for significant substructure in clusters hosting bent double-lobed radio sources compared to those with other types of radio sources.

  19. Curved crystal x-ray optics for monochromatic imaging with a clinical source.

    Science.gov (United States)

    Bingölbali, Ayhan; MacDonald, C A

    2009-04-01

    Monochromatic x-ray imaging has been shown to increase contrast and reduce dose relative to conventional broadband imaging. However, clinical sources with very narrow energy bandwidth tend to have limited intensity and field of view. In this study, focused fan beam monochromatic radiation was obtained using doubly curved monochromator crystals. While these optics have been in use for microanalysis at synchrotron facilities for some time, this work is the first investigation of the potential application of curved crystal optics to clinical sources for medical imaging. The optics could be used with a variety of clinical sources for monochromatic slot scan imaging. The intensity was assessed and the resolution of the focused beam was measured using a knife-edge technique. A simulation model was developed and comparisons to the measured resolution were performed to verify the accuracy of the simulation to predict resolution for different conventional sources. A simple geometrical calculation was also developed. The measured, simulated, and calculated resolutions agreed well. Adequate resolution and intensity for mammography were predicted for appropriate source/optic combinations.

  20. Entanglement swapping with independent sources over an optical-fiber network

    Science.gov (United States)

    Sun, Qi-Chao; Mao, Ya-Li; Jiang, Yang-Fan; Zhao, Qi; Chen, Si-Jing; Zhang, Wei; Zhang, Wei-Jun; Jiang, Xiao; Chen, Teng-Yun; You, Li-Xing; Li, Li; Huang, Yi-Dong; Chen, Xian-Feng; Wang, Zhen; Ma, Xiongfeng; Zhang, Qiang; Pan, Jian-Wei

    2017-03-01

    Establishing entanglement between two remote systems by the method of entanglement swapping is an essential step for a long-distance quantum network. Here we report a field-test entanglement swapping experiment with two independent telecommunication band entangled photon-pair sources over an optical fiber network in Hefei. The two sources are located at two nodes that are 12.5 km apart and the Bell-state measurement is performed at a third location which is connected to the two source nodes with 14.7-km and 10.6-km optical fibers, respectively. The observed average visibility is 79.9 ±4.8 % , which is sufficient for the violation of Bell inequalities. Furthermore, with the swapped entanglement, we demonstrate a source-independent quantum key distribution, which is also immune to any detection attacks at the measurement site.

  1. Analysis of Energy Efficiency in Dynamic Optical Networks Employing Solar Energy Sources

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2013-01-01

    The paper presents energy efficient routing in dynamic optical networks, where solar energy sources are employed for the network nodes. Different parameters are evaluated, including the number of nodes that have access to solar energy sources, the different maximum solar output power, traffic type...... and the locations of solar powered nodes. Results show a maximum 39% savings in energy consumption with different increases in connection blocking probability....

  2. At-wavelength metrology of x-ray optics at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Berujon, Sebastien; Sutter, John; Alcock, Simon G.; Sawhney, Kawal

    2014-09-01

    Modern, third-generation synchrotron radiation sources provide coherent and extremely bright beams of X-ray radiation. The successful exploitation of such beams depends to a significant extent on imperfections and misalignment of the optics employed on the beamlines. This issue becomes even more critical with the increasing use of active optics, and the desire to achieve diffraction-limited and coherence-preserving X-ray beams. In recent years, significant progress has been made to improve optic testing and optimization techniques, especially those using X-rays for so-called atwavelength metrology. These in-situ and at-wavelength metrology methods can be used not only to optimize the performance of X-ray optics, but also to correct and minimize the collective distortions of upstream beamline optics, including monochromators, and transmission windows. An overview of at-wavelength metrology techniques implemented at Diamond Light Source is presented, including grating interferometry and X-ray near-field speckle based techniques. Representative examples of the application of these techniques are also given, including in-situ and atwavelength calibration and optimization of: active, piezo bimorph mirrors; Kirkpatrick-Baez (KB) mirrors; and refractive optics such as compound refractive lenses.

  3. Radio over fiber transceiver employing phase modulation of an optical broadband source.

    Science.gov (United States)

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2010-10-11

    This paper proposes a low-cost RoF transceiver for multichannel SCM/WDM signal distribution suitable for future broadband access networks. The transceiver is based on the phase modulation of an optical broadband source centered at third transmission window. Prior to phase modulation the optical broadband source output signal is launched into a Mach-Zehnder interferometer structure, as key device enabling radio signals propagation over the optical link. Furthermore, an optical CWDM is employed to create a multichannel scenario by performing the spectral slicing of the modulated optical signal into a number of channels each one conveying the information from the central office to different base stations. The operation range is up to 20 GHz with a modulation bandwidth around of 500 MHz. Experimental results of the transmission of SCM QPSK and 64-QAM data through 20 Km of SMF exhibit good EVM results in the operative range determined by the phase-to-intensity conversion process. The proposed approach shows a great suitability for WDM networks based on RoF signal transport and also represents a cost-effective solution for passive optical networks.

  4. Broadband light source for fiber-optic measurement system in spaceborne applications

    Science.gov (United States)

    Rößner, Max R.; Müller, Mathias S.; Buck, Thorbjörn C.; Koch, Alexander W.

    2012-01-01

    Measuring temperatures, mechanical loads and derived quantities precisely and reliably play an important role in spaceflight. With spacecraft becoming increasingly complex, upscaling of present telemetry techniques can become cumbersome. Additionally, there are entirely new sensory requirements, resulting from emerging technologies such as smart structures, active vibration damping and composite material health monitoring. It has been demonstrated in preceding studies that these measurements can be advantageously and efficiently carried out by means of fiber-optic systems. The most prominent fiber-optic strain and temperature sensor is the fiber Bragg grating. Typically, multiple fiber Bragg gratings are used to translate entire temperature and strain fields into an optical wavelength information. For the interrogation of these sensors, a broadband or scanning light source is required. Additional requirements with respect to the light source are high intensity and unpolarized illumination of the gratings. These constraints can be met by a light source that is based on amplified spontaneous emission in a rare-earth-doped fiber. In the presented work, a compact light source, adapted for measurement applications and targeted towards space applications, has been developed. The design of this light source is presented, as well as its implementation. The light source has been designed and tested for selected core aspects of space robustness and the results of these tests are summarized.

  5. A linear ion optics model for extraction from a plasma ion source

    International Nuclear Information System (INIS)

    Dietrich, J.

    1987-01-01

    A linear ion optics model for ion extraction from a plasma ion source is presented, based on the paraxial equations which account for lens effects, space charge and finite source ion temperature. This model is applied to three- and four-electrode extraction systems with circular apertures. The results are compared with experimental data and numerical calculations in the literature. It is shown that the improved calculations of space charge effects and lens effects allow better agreement to be obtained than in earlier linear optics models. A principal result is that the model presented here describes the dependence of the optimum perveance on the aspect ratio in a manner similar to the nonlinear optics theory. (orig.)

  6. Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

    International Nuclear Information System (INIS)

    Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G.; Shea, H.

    2014-01-01

    Miniature ( 3 ) vapor-cell based devices using optical pumping of alkali atoms, such as atomic clocks and magnetometers, today mostly employ vertical-cavity surface-emitting lasers as pump light sources. Here, we report on the demonstration of optical pumping in a microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm 3 as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm 3 volume) test setup based on the M z magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors

  7. Optical pumping in a microfabricated Rb vapor cell using a microfabricated Rb discharge light source

    Energy Technology Data Exchange (ETDEWEB)

    Venkatraman, V.; Kang, S.; Affolderbach, C.; Mileti, G., E-mail: gaetano.mileti@unine.ch [Laboratoire Temps-Fréquence, University of Neuchâtel, Neuchâtel 2000 (Switzerland); Shea, H. [Microsystems for Space Technologies Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel 2002 (Switzerland)

    2014-02-03

    Miniature (optical pumping of alkali atoms, such as atomic clocks and magnetometers, today mostly employ vertical-cavity surface-emitting lasers as pump light sources. Here, we report on the demonstration of optical pumping in a microfabricated alkali vapor resonance cell using (1) a microfabricated Rb discharge lamp light source, as well as (2) a conventional glass-blown Rb discharge lamp. The microfabricated Rb lamp cell is a dielectric barrier discharge (DBD) light source, having the same inner cell volume of around 40 mm{sup 3} as that of the resonance cell, both filled with suitable buffer gases. A miniature (∼2 cm{sup 3} volume) test setup based on the M{sub z} magnetometer interrogation technique was used for observation of optical-radiofrequency double-resonance signals, proving the suitability of the microfabricated discharge lamp to introduce efficient optical pumping. The pumping ability of this light source was found to be comparable to or even better than that of a conventional glass-blown lamp. The reported results indicate that the micro-fabricated DBD discharge lamp has a high potential for the development of a new class of miniature atomic clocks, magnetometers, and quantum sensors.

  8. Spectral shaping for non-Gaussian source spectra in optical coherence tomography

    NARCIS (Netherlands)

    Tripathi, R; Nassif, N. A.; Nelson, JS; Park, B.H.; de Boer, JF

    2002-01-01

    We present a digital spectral shaping technique to reduce the sidelobes (ringing) of the axial point-spread function in optical coherence tomography for non-Gaussian-shaped source spectra. The spectra of two superluminescent diodes were combined to generate a spectrum with significant modulation.

  9. Optical identifications of celestial high energy sources with the Telescopio Nazionale Galileo

    International Nuclear Information System (INIS)

    Turriziani, Sara

    2012-01-01

    To ascertain the nature of celestial high energy sources, it is crucial to identify their optical counterparts. However, the currently available astronomical public optical databases do not provide an adequate support for a systematic high energy sources identification work. In particular, the optical limiting magnitude represents a severe limitation since the deepest flux limits reached by X-ray surveys require of course similarly deeper optical catalogs to homogeneously sample the available parameter space. Nonetheless, dedicated spectroscopic campaigns are being carried out successfully with the Telescopio Nazionale Galileo (TNG), a 4-m class telescope. To set up a winning observational campaign, the first and most important step is to define a strong science case, as it will allow for selections of good targets for observations: the key is to increase the identification efficiency while keeping down the required telescope time. In this context, as the Principal Investigator, I will give an overview of the first spectroscopic campaign carried out at the TNG to identify Swift X-ray serendipitous sources, and I will show the valuable results achieved with only one night of observations. As a second example, I will review the strategy for the northern-sky classification of candidate blazars associated to unidentified Fermi γ-ray sources, and I will show the results coming from the related observational campaign at TNG I have been involved during the last two years.

  10. A high field optical-pumping spin-exchange polarized deuterium source

    International Nuclear Information System (INIS)

    Coulter, K.P.; Holt, R.J.; Kinney, E.R.; Kowalczyk, R.S.; Poelker, M.; Potterveld, D.H.; Young, L.; Zeidman, B.; Toporkov, D.

    1992-01-01

    Recent results from a prototype high field optical-pumping spin-exchange polarized deuterium source are presented. Atomic polarization as high as 62% have been observed with an intensity of 6.3 x 10 17 atoms-sec -1 and 65% dissociation fraction

  11. Atomic and molecular spectroscopy with optical-frequency-comb-referenced IR coherent sources

    International Nuclear Information System (INIS)

    Cancio, P.; Bartalini, S.; De Rosa, M.; Giusfredi, G.; Mazzotti, D.; Maddaloni, P.; Vitiello, M. S.; De Natale, P.

    2013-01-01

    We provide a review of progress in the development of metrological-grade measurements in atomic and molecular systems through the extension, in the mid-infrared and far-infrared range, of optical frequency combs (OFCs) and the introduction of new techniques and highly coherent sources. (authors)

  12. Speckle-based at-wavelength metrology of x-ray optics at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Zhou, Tunhe; Kashyap, Yogesh; Sawhney, Kawal

    2017-08-01

    To achieve high resolution and sensitivity on the nanometer scale, further development of X-ray optics is required. Although ex-situ metrology provides valuable information about X-ray optics, the ultimate performance of X-ray optics is critically dependent on the exact nature of the working conditions. Therefore, it is equally important to perform in-situ metrology at the optics' operating wavelength (`at-wavelength' metrology) to optimize the performance of X-ray optics and correct and minimize the collective distortions of the upstream beamline optics, e.g. monochromator, windows, etc. Speckle-based technique has been implemented and further improved at Diamond Light Source. We have demonstrated that the angular sensitivity for measuring the slope error of an optical surface can reach an accuracy of two nanoradians. The recent development of the speckle-based at-wavelength metrology techniques will be presented. Representative examples of the applications of the speckle-based technique will also be given - including optimization of X-ray mirrors and characterization of compound refraction lenses. Such a high-precision metrology technique will be extremely beneficial for the manufacture and in-situ alignment/optimization of X-ray mirrors for next-generation synchrotron beamlines.

  13. Note: Tormenta: An open source Python-powered control software for camera based optical microscopy.

    Science.gov (United States)

    Barabas, Federico M; Masullo, Luciano A; Stefani, Fernando D

    2016-12-01

    Until recently, PC control and synchronization of scientific instruments was only possible through closed-source expensive frameworks like National Instruments' LabVIEW. Nowadays, efficient cost-free alternatives are available in the context of a continuously growing community of open-source software developers. Here, we report on Tormenta, a modular open-source software for the control of camera-based optical microscopes. Tormenta is built on Python, works on multiple operating systems, and includes some key features for fluorescence nanoscopy based on single molecule localization.

  14. Quasi-homogeneous partial coherent source modeling of multimode optical fiber output using the elementary source method

    Science.gov (United States)

    Fathy, Alaa; Sabry, Yasser M.; Khalil, Diaa A.

    2017-10-01

    Multimode fibers (MMF) have many applications in illumination, spectroscopy, sensing and even in optical communication systems. In this work, we present a model for the MMF output field assuming the fiber end as a quasi-homogenous source. The fiber end is modeled by a group of partially coherent elementary sources, spatially shifted and uncorrelated with each other. The elementary source distribution is derived from the far field intensity measurement, while the weighting function of the sources is derived from the fiber end intensity measurement. The model is compared with practical measurements for fibers with different core/cladding diameters at different propagation distances and for different input excitations: laser, white light and LED. The obtained results show normalized root mean square error less than 8% in the intensity profile in most cases, even when the fiber end surface is not perfectly cleaved. Also, the comparison with the Gaussian-Schell model results shows a better agreement with the measurement. In addition, the complex degree of coherence, derived from the model results, is compared with the theoretical predictions of the modified Van Zernike equation showing very good agreement, which strongly supports the assumption that the large core MMF could be considered as a quasi-homogenous source.

  15. Matrix light and pixel light: optical system architecture and requirements to the light source

    Science.gov (United States)

    Spinger, Benno; Timinger, Andreas L.

    2015-09-01

    Modern Automotive headlamps enable improved functionality for more driving comfort and safety. Matrix or Pixel light headlamps are not restricted to either pure low beam functionality or pure high beam. Light in direction of oncoming traffic is selectively switched of, potential hazard can be marked via an isolated beam and the illumination on the road can even follow a bend. The optical architectures that enable these advanced functionalities are diverse. Electromechanical shutters and lens units moved by electric motors were the first ways to realize these systems. Switching multiple LED light sources is a more elegant and mechanically robust solution. While many basic functionalities can already be realized with a limited number of LEDs, an increasing number of pixels will lead to more driving comfort and better visibility. The required optical system needs not only to generate a desired beam distribution with a high angular dynamic, but also needs to guarantee minimal stray light and cross talk between the different pixels. The direct projection of the LED array via a lens is a simple but not very efficient optical system. We discuss different optical elements for pre-collimating the light with minimal cross talk and improved contrast between neighboring pixels. Depending on the selected optical system, we derive the basic light source requirements: luminance, surface area, contrast, flux and color homogeneity.

  16. Sources of optical distortion in rapidly grown crystals of KH2PO4

    International Nuclear Information System (INIS)

    De Yoreo, J.J.; Zaitseva, N.P.; Woods, B.W.; Land, T.A.; Rek, Z.U.

    1995-01-01

    We report results of x-ray topographic and optical measurements on KH 2 PO 4 crystals grown at rates of 5 to 30mm/day. We show that optical distortion in these crystals is caused primarily by 3 sources: dislocations, differences in composition between adjacent growth sectors of the crystal, and differences in composition between adjacent sectors of vicinal growth hillocks within a single growth sector of the crystal. We find that the compositional heterogeneities cause spatial variations in the refractive index and induced distortion of the transmitted wave front while large groups of dislocations are responsible for strain induced birefringence which leads to beam depolarization

  17. Numerical modeling of optical coherent transient processes with complex configurations-III: Noisy laser source

    International Nuclear Information System (INIS)

    Chang Tiejun; Tian Mingzhen

    2007-01-01

    A previously developed numerical model based on Maxwell-Bloch equations was modified to simulate optical coherent transient and spectral hole burning processes with noisy laser sources. Random walk phase noise was simulated using laser-phase sequences generated numerically according to the normal distribution of the phase shift. The noise model was tested by comparing the simulated spectral hole burning effect with the analytical solution. The noise effects on a few typical optical coherence transient processes were investigated using this numerical tool. Flicker and random walk frequency noises were considered in accumulation process

  18. Dye molecules as single-photon sources and large optical nonlinearities on a chip

    International Nuclear Information System (INIS)

    Hwang, J; Hinds, E A

    2011-01-01

    We point out that individual organic dye molecules, deposited close to optical waveguides on a photonic chip, can act as single-photon sources. A thin silicon nitride strip waveguide is expected to collect 28% of the photons from a single dibenzoterrylene molecule. These molecules can also provide large, localized optical nonlinearities, which are enough to discriminate between one photon or two through a differential phase shift of 2 0 per photon. This new atom-photon interface may be used as a resource for processing quantum information.

  19. Apertureless near-field scanning optical microscope working with or without laser source.

    Science.gov (United States)

    Formanek, F; De Wilde, Y; Aigouy, L; Chen, Y

    2004-01-01

    An apertureless near-field scanning optical microscope (ANSOM), used indifferent configurations, is presented. Our versatile home-made setup, based on a sharp tungsten tip glued onto a quartz tuning fork and working in tapping mode, allows to perform imaging over a broad spectral range. We have recorded optical images in the visible (wavelength, lambda = 655 nm) and in the infrared (lambda = 10.6 microm), proving that the setup routinely achieves an optical resolution of images recorded in the visible (lambda = 655 nm) in an inverted configuration where the tip does not perturb the focused spot of the illumination laser. Approach curves as well as image profiles have revealed that on demodulating the optical signal at higher harmonics, we can obtain an effective probe sharpening which results in an improvement of the resolution. Finally, we have presented optical images recorded in the infrared without any illumination, that is, the usual laser source is replaced by a simple heating of the sample. This has shown that the ANSOM can be used as a near-field thermal optical microscope (NTOM) to probe the near field generated by the thermal emission of the sample.

  20. Effects of source shape on the numerical aperture factor with a geometrical-optics model.

    Science.gov (United States)

    Wan, Der-Shen; Schmit, Joanna; Novak, Erik

    2004-04-01

    We study the effects of an extended light source on the calibration of an interference microscope, also referred to as an optical profiler. Theoretical and experimental numerical aperture (NA) factors for circular and linear light sources along with collimated laser illumination demonstrate that the shape of the light source or effective aperture cone is critical for a correct NA factor calculation. In practice, more-accurate results for the NA factor are obtained when a linear approximation to the filament light source shape is used in a geometric model. We show that previously measured and derived NA factors show some discrepancies because a circular rather than linear approximation to the filament source was used in the modeling.

  1. Brilliant radiation sources by laser-plasma accelerators and optical undulators

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Alexander

    2012-09-06

    This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

  2. Brilliant radiation sources by laser-plasma accelerators and optical undulators

    International Nuclear Information System (INIS)

    Debus, Alexander

    2012-01-01

    This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

  3. Limit of detection of a fiber optics gyroscope using a super luminescent radiation source

    International Nuclear Information System (INIS)

    Sandoval R, G.E.; Nikolaev, V.A.

    2003-01-01

    The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the super luminescent emission source based on doped optical fiber with rare earth elements (Super luminescent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristics limits of the FOG sensibility. By using this type of emission source in the FOG is recommend to use the rate when the direction of the pumping signal coincide with the super luminescent signal. The most results are the proposition and argumentation of the SFS election as emission source to be use in the FOG of the phase type. Such a decision allow to increase the characteristics of the FOG sensibility in comparison with the use of luminescent source of semiconductors emission which are extensively used in the present time. The use of emission source of the SFS type allow to come closer to the threshold of the obtained sensibility limit (detection limit) which is determined with the shot noise. (Author)

  4. Collimating lens for light-emitting-diode light source based on non-imaging optics.

    Science.gov (United States)

    Wang, Guangzhen; Wang, Lili; Li, Fuli; Zhang, Gongjian

    2012-04-10

    A collimating lens for a light-emitting-diode (LED) light source is an essential device widely used in lighting engineering. Lens surfaces are calculated by geometrical optics and nonimaging optics. This design progress does not rely on any software optimization and any complex iterative process. This method can be used for any type of light source not only Lambertian. The theoretical model is based on point source. But the practical LED source has a certain size. So in the simulation, an LED chip whose size is 1 mm*1 mm is used to verify the feasibility of the model. The mean results show that the lenses have a very compact structure and good collimating performance. Efficiency is defined as the ratio of the flux in the illuminated plane to the flux from LED source without considering the lens material transmission. Just investigating the loss in the designed lens surfaces, the two types of lenses have high efficiencies of more than 90% and 99%, respectively. Most lighting area (possessing 80% flux) radii are no more than 5 m when the illuminated plane is 200 m away from the light source.

  5. Limit of detection of a fiber optics gyroscope using a super luminescent radiation source

    CERN Document Server

    Sandoval, G E

    2003-01-01

    The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the super luminescent emission source based on doped optical fiber with rare earth elements (Super luminescent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristics limits of the FOG sensibility. By using this type of emission source in the FOG is recommend to use the rate when the direction of the pumping signal coincide with the super luminescent signal. The most results are the proposition and argumentation of the SFS election as emission source to be use in the FOG of the phase type. Such a decision allow to increase the characteristics of the FOG sensibility in comparison with the use of luminescent source of semiconductors emission which are extensively used in the present time. The use of emission source of the SFS type allow to come closer to the threshold of the obtained sensibility limit (detection limit) which i...

  6. The cryogenic cooling program in high-heat-load optics at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Rogers, C.S.

    1993-07-01

    This paper describes some of the aspects of the cryogenic optics program at the Advanced Photon Source (APS). A liquid-nitrogen-cooled, high-vacuum, double crystal monochromator is being fabricated at Argonne National Laboratory (ANL). A pumping system capable of delivering a variable flow rate of up to 10 gallons per minute of pressurized liquid nitrogen and removing 5 kilowatts of x-ray power is also being constructed. This specialized pumping system and monochromator will be used to test the viability of cryogenically cooled, high-heat-load synchrotron optics. It has been determined that heat transfer enhancement will be required for optics used with APS insertion devices. An analysis of a porous-matrix-enhanced monochromator crystal is presented. For the particular case investigated, a heat transfer enhancement factor of 5 to 6 was calculated

  7. A radio/optical reference frame. 5: Additional source positions in the mid-latitude southern hemisphere

    Science.gov (United States)

    Russell, J. L.; Reynolds, J. E.; Jauncey, D. L.; de Vegt, C.; Zacharias, N.; Ma, C.; Fey, A. L.; Johnston, K. J.; Hindsley, R.; Hughes, J. A.; Malin, D. F.; White, G. L.; Kawaguchi, N.; Takahashi, Y.

    1994-01-01

    We report new accurate radio position measurements for 30 sources, preliminary positions for two sources, improved radio postions for nine additional sources which had limited previous observations, and optical positions and optical-radio differences for six of the radio sources. The Very Long Baseline Interferometry (VLBI) observations are part of the continuing effort to establish a global radio reference frame of about 400 compact, flat spectrum sources, which are evenly distributed across the sky. The observations were made using Mark III data format in four separate sessions in 1988-89 with radio telescopes at Tidbinbilla, Australia, Kauai, USA, and Kashima, Japan. We observed a total of 54 sources, including ten calibrators and three which were undetected. The 32 new source positions bring the total number in the radio reference frame catalog to 319 (172 northern and 147 southern) and fill in the zone -25 deg greater than delta greater than -45 deg which, prior to this list, had the lowest source density. The VLBI positions have an average formal precision of less than 1 mas, although unknown radio structure effects of about 1-2 mas may be present. The six new optical postion measurements are part of the program to obtain positions of the optical counterparts of the radio reference frame source and to map accurately the optical on to the radio reference frames. The optical measurements were obtained from United States Naval Observatory (USNO) Black Birch astrograph plates and source plates from the AAT, and Kitt Peak National Observatory (KPNO) 4 m, and the European Southern Observatory (ESO) Schmidt. The optical positions have an average precision of 0.07 sec, mostly due to the zero point error when adjusted to the FK5 optical frame using the IRS catalog. To date we have measured optical positions for 46 sources.

  8. INVESTIGATING THE OPTICAL COUNTERPART CANDIDATES OF FOUR INTEGRAL SOURCES LOCALIZED WITH CHANDRA

    International Nuclear Information System (INIS)

    Özbey Arabacı, Mehtap; Kalemci, Emrah; Tomsick, John A.; Bodaghee, Arash; Halpern, Jules; Chaty, Sylvain; Rodriguez, Jerome; Rahoui, Farid

    2012-01-01

    We report on the optical spectroscopic follow-up observations of the candidate counterparts to four INTEGRAL sources: IGR J04069+5042, IGR J06552–1146, IGR J21188+4901, and IGR J22014+6034. The candidate counterparts were determined with Chandra, and the optical observations were performed with 1.5 m RTT-150 telescope (TÜBİTAK National Observatory, Antalya, Turkey) and 2.4 m Hiltner Telescope (MDM Observatory, Kitt Peak, Arizona). Our spectroscopic results show that one of the two candidates of IGR J04069+5042 and the one observed for IGR J06552–1146 could be active late-type stars in RS CVn systems. However, according to the likelihood analysis based on Chandra and INTEGRAL, two optically weaker sources in the INTEGRAL error circle of IGR J06552–1146 have higher probabilities to be the actual counterpart. The candidate counterparts of IGR J21188+4901 are classified as an active M-type star and a late-type star. Among the optical spectra of four candidates of IGR J22014+6034, two show Hα emission lines, one is a late-type star, and the other is an M type. The likelihood analysis favors a candidate with no distinguishing features in the optical spectrum. Two of the candidates classified as M-type dwarfs, are similar to some IGR candidates claimed to be symbiotic stars. However, some of the prominent features of symbiotic systems are missing in our spectra, and their NIR colors are not consistent with those expected for giants. We consider the IR colors of all IGR candidates claimed to be symbiotic systems and find that low-resolution optical spectrum may not be enough for conclusive identification.

  9. Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

    DEFF Research Database (Denmark)

    Bravo Gonzalo, Ivan; Engelsholm, Rasmus Dybbro; Bang, Ole

    2017-01-01

    bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which...... the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation...... (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise...

  10. Integration of highly probabilistic sources into optical quantum architectures: perpetual quantum computation

    International Nuclear Information System (INIS)

    Devitt, Simon J; Stephens, Ashley M; Munro, William J; Nemoto, Kae

    2011-01-01

    In this paper, we introduce a design for an optical topological cluster state computer constructed exclusively from a single quantum component. Unlike previous efforts we eliminate the need for on demand, high fidelity photon sources and detectors and replace them with the same device utilized to create photon/photon entanglement. This introduces highly probabilistic elements into the optical architecture while maintaining complete specificity of the structure and operation for a large-scale computer. Photons in this system are continually recycled back into the preparation network, allowing for an arbitrarily deep three-dimensional cluster to be prepared using a comparatively small number of photonic qubits and consequently the elimination of high-frequency, deterministic photon sources.

  11. The Atomic, Molecular and Optical Science instrument at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, Ken R. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Department of Applied Physics, Stanford University, 348 Via Pueblo, Stanford, CA 94305 (United States); Bucher, Maximilian; Bozek, John D.; Carron, Sebastian; Castagna, Jean-Charles [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Coffee, Ryan [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Pulse Institute, Stanford University and SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Curiel, G. Ivan; Holmes, Michael; Krzywinski, Jacek; Messerschmidt, Marc; Minitti, Michael; Mitra, Ankush; Moeller, Stefan; Noonan, Peter; Osipov, Timur; Schorb, Sebastian; Swiggers, Michele; Wallace, Alexander; Yin, Jing [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Bostedt, Christoph, E-mail: bostedt@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Pulse Institute, Stanford University and SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2015-04-17

    A description of the Atomic, Molecular and Optical Sciences (AMO) instrument at the Linac Coherent Light Source is presented. Recent scientific highlights illustrate the imaging, time-resolved spectroscopy and high-power density capabilities of the AMO instrument. The Atomic, Molecular and Optical Science (AMO) instrument at the Linac Coherent Light Source (LCLS) provides a tight soft X-ray focus into one of three experimental endstations. The flexible instrument design is optimized for studying a wide variety of phenomena requiring peak intensity. There is a suite of spectrometers and two photon area detectors available. An optional mirror-based split-and-delay unit can be used for X-ray pump–probe experiments. Recent scientific highlights illustrate the imaging, time-resolved spectroscopy and high-power density capabilities of the AMO instrument.

  12. Optical and spectroscopic studies on tannery wastes as a possible source of organic semiconductors

    Science.gov (United States)

    Nashy, El-Shahat H. A.; Al-Ashkar, Emad; Abdel Moez, A.

    2012-02-01

    Tanning industry produces a large quantity of solid wastes which contain hide proteins in the form of protein shavings containing chromium salts. The chromium wastes are the main concern from an environmental stand point of view, because chrome wastes posses a significant disposal problem. The present work is devoted to investigate the possibility of utilizing these wastes as a source of organic semi-conductors as an alternative method instead of the conventional ones. The chemical characterization of these wastes was determined. In addition, the Horizontal Attenuated Total Reflection (HATR) FT-IR spectroscopic analysis and optical parameters were also carried out for chromated samples. The study showed that the chromated samples had suitable absorbance and transmittance in the wavelength range (500-850 nm). Presence of chromium salt in the collagen samples increases the absorbance which improves the optical properties of the studied samples and leads to decrease the optical energy gap. The obtained optical energy gap gives an impression that the environmentally hazardous chrome shavings wastes can be utilized as a possible source of natural organic semiconductors with direct and indirect energy gap. This work opens the door to use some hazardous wastes in the manufacture of electronic devices such as IR-detectors, solar cells and also as solar cell windows.

  13. Open-source algorithm for detecting sea ice surface features in high-resolution optical imagery

    Directory of Open Access Journals (Sweden)

    N. C. Wright

    2018-04-01

    Full Text Available Snow, ice, and melt ponds cover the surface of the Arctic Ocean in fractions that change throughout the seasons. These surfaces control albedo and exert tremendous influence over the energy balance in the Arctic. Increasingly available meter- to decimeter-scale resolution optical imagery captures the evolution of the ice and ocean surface state visually, but methods for quantifying coverage of key surface types from raw imagery are not yet well established. Here we present an open-source system designed to provide a standardized, automated, and reproducible technique for processing optical imagery of sea ice. The method classifies surface coverage into three main categories: snow and bare ice, melt ponds and submerged ice, and open water. The method is demonstrated on imagery from four sensor platforms and on imagery spanning from spring thaw to fall freeze-up. Tests show the classification accuracy of this method typically exceeds 96 %. To facilitate scientific use, we evaluate the minimum observation area required for reporting a representative sample of surface coverage. We provide an open-source distribution of this algorithm and associated training datasets and suggest the community consider this a step towards standardizing optical sea ice imagery processing. We hope to encourage future collaborative efforts to improve the code base and to analyze large datasets of optical sea ice imagery.

  14. Simulation of multicomponent light source for optical-electronic system of color analysis objects

    Science.gov (United States)

    Peretiagin, Vladimir S.; Alekhin, Artem A.; Korotaev, Valery V.

    2016-04-01

    Development of lighting technology has led to possibility of using LEDs in the specialized devices for outdoor, industrial (decorative and accent) and domestic lighting. In addition, LEDs and devices based on them are widely used for solving particular problems. For example, the LED devices are widely used for lighting of vegetables and fruit (for their sorting or growing), textile products (for the control of its quality), minerals (for their sorting), etc. Causes of active introduction LED technology in different systems, including optical-electronic devices and systems, are a large choice of emission color and LED structure, that defines the spatial, power, thermal and other parameters. Furthermore, multi-element and color devices of lighting with adjustable illumination properties can be designed and implemented by using LEDs. However, devices based on LEDs require more attention if you want to provide a certain nature of the energy or color distribution at all the work area (area of analysis or observation) or surface of the object. This paper is proposed a method of theoretical modeling of the lighting devices. The authors present the models of RGB multicomponent light source applied to optical-electronic system for the color analysis of mineral objects. The possibility of formation the uniform and homogeneous on energy and color illumination of the work area for this system is presented. Also authors showed how parameters and characteristics of optical radiation receiver (by optical-electronic system) affect on the energy, spatial, spectral and colorimetric properties of a multicomponent light source.

  15. Optical and spectroscopic studies on tannery wastes as a possible source of organic semiconductors.

    Science.gov (United States)

    Nashy, El-Shahat H A; Al-Ashkar, Emad; Moez, A Abdel

    2012-02-01

    Tanning industry produces a large quantity of solid wastes which contain hide proteins in the form of protein shavings containing chromium salts. The chromium wastes are the main concern from an environmental stand point of view, because chrome wastes posses a significant disposal problem. The present work is devoted to investigate the possibility of utilizing these wastes as a source of organic semi-conductors as an alternative method instead of the conventional ones. The chemical characterization of these wastes was determined. In addition, the Horizontal Attenuated Total Reflection (HATR) FT-IR spectroscopic analysis and optical parameters were also carried out for chromated samples. The study showed that the chromated samples had suitable absorbance and transmittance in the wavelength range (500-850 nm). Presence of chromium salt in the collagen samples increases the absorbance which improves the optical properties of the studied samples and leads to decrease the optical energy gap. The obtained optical energy gap gives an impression that the environmentally hazardous chrome shavings wastes can be utilized as a possible source of natural organic semiconductors with direct and indirect energy gap. This work opens the door to use some hazardous wastes in the manufacture of electronic devices such as IR-detectors, solar cells and also as solar cell windows. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Open-source algorithm for detecting sea ice surface features in high-resolution optical imagery

    Science.gov (United States)

    Wright, Nicholas C.; Polashenski, Chris M.

    2018-04-01

    Snow, ice, and melt ponds cover the surface of the Arctic Ocean in fractions that change throughout the seasons. These surfaces control albedo and exert tremendous influence over the energy balance in the Arctic. Increasingly available meter- to decimeter-scale resolution optical imagery captures the evolution of the ice and ocean surface state visually, but methods for quantifying coverage of key surface types from raw imagery are not yet well established. Here we present an open-source system designed to provide a standardized, automated, and reproducible technique for processing optical imagery of sea ice. The method classifies surface coverage into three main categories: snow and bare ice, melt ponds and submerged ice, and open water. The method is demonstrated on imagery from four sensor platforms and on imagery spanning from spring thaw to fall freeze-up. Tests show the classification accuracy of this method typically exceeds 96 %. To facilitate scientific use, we evaluate the minimum observation area required for reporting a representative sample of surface coverage. We provide an open-source distribution of this algorithm and associated training datasets and suggest the community consider this a step towards standardizing optical sea ice imagery processing. We hope to encourage future collaborative efforts to improve the code base and to analyze large datasets of optical sea ice imagery.

  17. X-ray optics developments at the APS for third-generation synchrotron radiation sources

    International Nuclear Information System (INIS)

    Mills, D.M.

    1996-09-01

    High brilliance third-generation synchrotron radiation sources simultaneously provide both a need and an opportunity for the development of new x-ray optical components. The high power and power densities of the x-ray beams produced by insertion devices have forced researchers to consider novel, and what may seem like exotic, approaches to the mitigation of thermal distortions that can dilute the beam brilliance delivered to the experiment or next optical component. Once the power has been filtered by such high heat load optical elements, specialized components can be employed that take advantage of the high degree of brilliance. This presentation reviews the performance of optical components that have been designed, fabricated, and tested at the Advanced Photon Source, starting with high heat load components and followed by examples of several specialized devices such as a milli-eV resolution (in-line) monochromator, a high energy x-ray phase retarder, and a phase zone plate with submicron focusing capability

  18. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2013-07-01

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  19. Support systems for optics in the experiment stations at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Barraza, J.; Shu, D.; Kuzay, T.M.

    1994-01-01

    Support systems have been designed for optics in the experiment stations of the Advanced Photon Source at Argonne National Laboratory. These systems utilize modular precision positioning slides and stages arranged in 3-point kinematic mount fashion for optimum mechanical stability. Through the use of novel configurations, these systems can achieve large linear motions, six degree-of-freedom motion, and large load capacities without sacrificing valuable experimental station space. This paper will discuss the designs and specifications of the positioning systems developed

  20. HST/ACS Imaging of Omega Centauri: Optical Counterparts of Chandra X-Ray Sources

    Science.gov (United States)

    Cool, Adrienne M.; Haggard, Daryl; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Anderson, Jay

    2013-02-01

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central ~10' × 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, ~40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M 625 =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in ω Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in ω to Cen 20, the largest number yet known in any globular cluster.

  1. Energy Efficient Routing Algorithms in Dynamic Optical Core Networks with Dual Energy Sources

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2013-01-01

    This paper proposes new energy efficient routing algorithms in optical core networks, with the application of solar energy sources and bundled links. A comprehensive solar energy model is described in the proposed network scenarios. Network performance in energy savings, connection blocking...... probability, resource utilization and bundled link usage are evaluated with dynamic network simulations. Results show that algorithms proposed aiming for reducing the dynamic part of the energy consumption of the network may raise the fixed part of the energy consumption meanwhile....

  2. Water soluble organic aerosols in the Colorado Rocky Mountains, USA: composition, sources and optical properties

    OpenAIRE

    Xie, Mingjie; Mladenov, Natalie; Williams, Mark W.; Neff, Jason C.; Wasswa, Joseph; Hannigan, Michael P.

    2016-01-01

    Atmospheric aerosols have been shown to be an important input of organic carbon and nutrients to alpine watersheds and influence biogeochemical processes in these remote settings. For many remote, high elevation watersheds, direct evidence of the sources of water soluble organic aerosols and their chemical and optical characteristics is lacking. Here, we show that the concentration of water soluble organic carbon (WSOC) in the total suspended particulate (TSP) load at a high elevation site in...

  3. Realization of rapid debugging for detection circuit of optical fiber gas sensor: Using an analog signal source

    Science.gov (United States)

    Tian, Changbin; Chang, Jun; Wang, Qiang; Wei, Wei; Zhu, Cunguang

    2015-03-01

    An optical fiber gas sensor mainly consists of two parts: optical part and detection circuit. In the debugging for the detection circuit, the optical part usually serves as a signal source. However, in the debugging condition, the optical part can be easily influenced by many factors, such as the fluctuation of ambient temperature or driving current resulting in instability of the wavelength and intensity for the laser; for dual-beam sensor, the different bends and stresses of the optical fiber will lead to the fluctuation of the intensity and phase; the intensity noise from the collimator, coupler, and other optical devices in the system will also result in the impurity of the optical part based signal source. In order to dramatically improve the debugging efficiency of the detection circuit and shorten the period of research and development, this paper describes an analog signal source, consisting of a single chip microcomputer (SCM), an amplifier circuit, and a voltage-to-current conversion circuit. It can be used to realize the rapid debugging detection circuit of the optical fiber gas sensor instead of optical part based signal source. This analog signal source performs well with many other advantages, such as the simple operation, small size, and light weight.

  4. Single Photon Source with a Diamond Nanocrystal on an Optical Nanofiber

    International Nuclear Information System (INIS)

    Lars Liebermeister

    2014-01-01

    The development of high yield single photon sources is crucial for applications in quantum information science as well as for experiments on the foundations of quantum physics. The NV-center in diamond is a promising solid state candidate. By using nanodiamonds the single photon emission can easily be coupled to integrated nano-optical and plasmonic structures. Our approach is to utilize efficient coupling of fluorescence of a single NV-center to the evanescent field of an optical nanofiber. A hybrid microscope (confocal microscope combined with an AFM) allows to optically characterize and preselect diamond nanocrystals and then to apply an AFM nanomanipulation technique to move a selected nanodiamond deterministically onto the tapered optical fiber. We report on first results with single diamond nanocrystals containing several NV-centers positioned on a tapered optical fiber. We observe fluorescence emission in the guided mode of the fiber. The second order correlation recorded between the free-space and the guided fluorescence shows pronounced antibunching. This demonstrated efficient evanescent coupling with low background. (author)

  5. An inexpensive way to analyze the optics of electrostatic, surface-ionization ion-source configurations

    International Nuclear Information System (INIS)

    Balestrini, S.J.

    1986-01-01

    The optical characteristics of surface ionization sources can often be studied in detail with the aid of a home computer. Sources with two-dimensional symmetry are considered. Ions are created on the surface of a hot filament. An accelerating voltage, V, is applied to the source and filament. The ions are accelerated and focused into a beam by a series of electrodes containing narrow axial slits. The ordering of elementary stages of acceleration that the electrodes form from is the optical stack. The focusing parameters are the fractions of the source voltage applied to the electrodes. A portion of the ions leaves the source through a beam-defining, collimating slit in the final electrode. An ion trajectory at any point along the symmetry axis is described by a vector with two phase space components, which are treated as small quantities. The components at the filament are ω, the displacement from the symmetry axis, and ν, the velocity component of the ion parallel to the filament surface divided by its speed when it leaves the first stage. Elsewhere, the trajectory components are the displacement from the symmetry axis and the slope

  6. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations

    International Nuclear Information System (INIS)

    Ageron, Michel; Al Samarai, Imen; Akerlof, Carl; Basa, Stéphane; Bertin, Vincent; Boer, Michel; Brunner, Juergen; Busto, Jose; Dornic, Damien; Klotz, Alain; Schussler, Fabian; Vallage, Bertrand; Vecchi, Manuela; Zheng, Weikang

    2012-01-01

    The ANTARES telescope is well suited to detect neutrinos produced in astrophysical transient sources as it can observe a full hemisphere of the sky at all the times with a duty cycle close to unity and an angular resolution better than 0.5°. Potential sources include gamma-ray bursts (GRBs), core collapse supernovae (SNe), and flaring active galactic nuclei (AGNs). To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated one or two times per month for special events such as two or more neutrinos coincident in time and direction or single neutrinos of very high energy. Since February 2009, ANTARES has sent 37 alert triggers to the TAROT and ROTSE telescope networks, 27 of them have been followed. First results on the optical images analysis to search for GRBs are presented.

  7. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations

    Science.gov (United States)

    Ageron, Michel; Al Samarai, Imen; Akerlof, Carl; Basa, Stéphane; Bertin, Vincent; Boer, Michel; Brunner, Juergen; Busto, Jose; Dornic, Damien; Klotz, Alain; Schussler, Fabian; Vallage, Bertrand; Vecchi, Manuela; Zheng, Weikang

    2012-11-01

    The ANTARES telescope is well suited to detect neutrinos produced in astrophysical transient sources as it can observe a full hemisphere of the sky at all the times with a duty cycle close to unity and an angular resolution better than 0.5°. Potential sources include gamma-ray bursts (GRBs), core collapse supernovae (SNe), and flaring active galactic nuclei (AGNs). To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated one or two times per month for special events such as two or more neutrinos coincident in time and direction or single neutrinos of very high energy. Since February 2009, ANTARES has sent 37 alert triggers to the TAROT and ROTSE telescope networks, 27 of them have been followed. First results on the optical images analysis to search for GRBs are presented.

  8. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations

    Energy Technology Data Exchange (ETDEWEB)

    Ageron, Michel [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Al Samarai, Imen, E-mail: samarai@cppm.in2p3.fr [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Akerlof, Carl [Randall Laboratory of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109-1040 (United States); Basa, Stephane [LAM, BP8, Traverse du siphon, 13376 Marseille Cedex 12 (France); Bertin, Vincent [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Boer, Michel [OHP, 04870 Saint Michel de l' Observatoire (France); Brunner, Juergen; Busto, Jose; Dornic, Damien [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Klotz, Alain [OHP, 04870 Saint Michel de l' Observatoire (France); IRAP, 9 avenue du colonel Roche, 31028 Toulouse Cedex 4 (France); Schussler, Fabian; Vallage, Bertrand [CEA-IRFU, centre de Saclay, 91191 Gif-sur-Yvette (France); Vecchi, Manuela [CPPM, CNRS/IN2P3 - Universite de Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Zheng, Weikang [Randall Laboratory of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109-1040 (United States)

    2012-11-11

    The ANTARES telescope is well suited to detect neutrinos produced in astrophysical transient sources as it can observe a full hemisphere of the sky at all the times with a duty cycle close to unity and an angular resolution better than 0.5 Degree-Sign . Potential sources include gamma-ray bursts (GRBs), core collapse supernovae (SNe), and flaring active galactic nuclei (AGNs). To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated one or two times per month for special events such as two or more neutrinos coincident in time and direction or single neutrinos of very high energy. Since February 2009, ANTARES has sent 37 alert triggers to the TAROT and ROTSE telescope networks, 27 of them have been followed. First results on the optical images analysis to search for GRBs are presented.

  9. Optical Counterparts for Low-Luminosity X-ray Sources in Omega Centauri

    Science.gov (United States)

    Cool, Adrienne

    2002-07-01

    We propose to use narrow-band HAlpha imaging with ACS to search for the optical counterparts of low-luminosity X-ray sources {Lx 2 x 10^30 - 5 x 10^32 erg/s} in the globular cluster Omega Centauri. With 9 WFC fields, we will cover the inner two core radii of the cluster, and encompass about 90 of the faint sources we have identified with Chandra. Approximately 30-50 of these sources should be cluster members, the remainder being mostly background galaxies plus a smaller number of foreground stars. This large population of low-Lx cluster X-ray sources is second only to the more than 100 faint sources recently discovered in 47 Tuc with Chandra {Grindlay et al. 2001a}, which have been identified as a mixture of cataclysmic variables, quiescent low-mass X-ray binaries, millisecond pulsars, and coronally active main-sequence binaries. Our Cycle 6 WFPC2 program successfully identified 2 of the 3 then-known faint X-ray sources in the core of Omega Cen using H-alpha imaging. We now propose to expand the areal coverage by a factor of about 18 to encompass the much larger number of sources that have since been discovered with Chandra. The extreme crowding in the central regions of Omega Cen requires the resolution of HST to obtain optical IDs. These identifications are key to making meaningful comparisons between the populations of faint X-ray sources in different clusters, in an effort to understand their origins and role in cluster dynamics.

  10. Novel high resolution 125I brachytherapy source dosimetry using Ge-doped optical fibres

    International Nuclear Information System (INIS)

    Issa, Fatma; Hugtenburg, Richard P.; Nisbet, Andrew; Bradley, David A.

    2013-01-01

    The steep dose gradients close to brachytherapy sources limit the ability to obtain accurate measurements of dose. Here we use a novel high spatial resolution dosimeter to measure dose around a 125 I source and compare against simulations. Ge-doped optical fibres, used as thermoluminescent dosimeters, offer sub-mm spatial resolution, linear response from 10 cGy to >1 kGy and dose-rate independence. For a 125 I brachytherapy seed in a PMMA phantom, doses were obtained for source-dosimeter separations from 0.1 cm up to several cm, supported by EGSnrc/DOSRZznrc Monte Carlo simulations and treatment planning system data. The measurements agree with simulations to within 2.3%±0.3% along the transverse and perpendicular axes and within 3.0%±0.5% for measurements investigating anisotropy in angular dose distribution. Measured and Veriseed™ brachytherapy treatment planning system (TPS) values agreed to within 2.7%±0.5%. Ge-doped optical fibre dosimeters allow detailed dose mapping around brachytherapy sources, not least in situations of high dose gradient. - Highlights: • We evaluate fall-off in dose for distances from an 125 I source of 1 mm to 60 mm. • The TL of optical fibres accommodate high dose gradients and doses that reduce by a factor of 10 3 across the range of separations. • We verify measured values using DOSRZnrc Monte Carlo code simulations and the Variseed™ Treatment Planning System. • Measured radial and angular dose are obtained with ≤3% uncertainty

  11. The gridless plasma ion source (GIS) for plasma ion assisted optical coating

    International Nuclear Information System (INIS)

    You Dawei; Li Xiaoqian; Wang Yu; Lin Yongchang

    2004-01-01

    High-quality optical coating is a key technology for modern optics. Ion-assisted deposition technology was used to improve the vaporized coating in 1980's. The GIS (gridless ion source), which is an advanced plasma source for producing a high-quality optical coating in large area, can produce a large area uniformity>1000 mm (diameter), a high ion current density ∼0.5 mA/cm 2 , 20 eV-200 eV energetic plasma ions and can activate reactive gas and film atoms. Now we have developed a GIS system. The GIS and the plasma ion-assisted deposition technology are investigated to achieve a high-quality optical coating. The GIS is a high power and high current source with a power of 1 kW-7.5 kW, a current of 10 A- 70 A and an ion density of 200 μA/cm 2 -500 μA/cm 2 . Because of the special magnetic structure, the plasma-ion extraction efficiency has been improved to obtain a maximum ion density of 500 μA/cm 2 in the medium power (∼4 kW) level. The GIS applied is of a special cathode structure, so that the GIS operation can be maintained under a rather low power and the lifetime of cathode will be extended. The GIS has been installed in the LPSX-1200 type box coating system. The coated TiO 2 , SiO 2 films such as antireflective films with the system have the same performance reported by Leybold Co, 1992, along with a controllable refractive index and film structure. (authors)

  12. Analysis of the emission characteristics of ion sources for high-value optical counting processes

    International Nuclear Information System (INIS)

    Beermann, Nils

    2009-01-01

    The production of complex high-quality thin film systems requires a detailed understanding of all partial processes. One of the most relevant partial processes is the condensation of the coating material on the substrate surface. The optical and mechanical material properties can be adjusted by the well-defined impingement of energetic ions during deposition. Thus, in the past, a variety of different ion sources were developed. With respect to the present and future challenges in the production of precisely fabricated high performance optical coatings, the ion emission of the sources has commonly not been characterized sufficiently so far. This question is addressed in the frame of this work which itself is thematically integrated in the field of process-development and -control of ion assisted deposition processes. In a first step, a Faraday cup measurement system was developed which allows the spatially resolved determination of the ion energy distribution as well as the ion current distribution. Subsequently, the ion emission profiles of six ion sources were determined depending on the relevant operating parameters. Consequently, a data pool for process planning and supplementary process analysis is made available. On the basis of the acquired results, the basic correlations between the operating parameters and the ion emission are demonstrated. The specific properties of the individual sources as well as the respective control strategies are pointed out with regard to the thin film properties and production yield. Finally, a synthesis of the results and perspectives for future activities are given. (orig.)

  13. Clinical utility of anterior segment swept-source optical coherence tomography in glaucoma

    Directory of Open Access Journals (Sweden)

    Dewang Angmo

    2016-01-01

    Full Text Available Optical coherence tomography (OCT, a noninvasive imaging modality that uses low-coherence light to obtain a high-resolution cross-section of biological structures, has evolved dramatically over the years. The Swept-source OCT (SS-OCT makes use of a single detector with a rapidly tunable laser as a light source. The Casia SS-1000 OCT is a Fourier-domain, SS-OCT designed specifically for imaging the anterior segment. This system achieves high resolution imaging of 10΅m (Axial and 30΅m (Transverse and high speed scanning of 30,000 A-scans per second. With a substantial improvement in scan speed, the anterior chamber angles can be imaged 360 degrees in 128 cross sections (each with 512 A-scans in about 2.4 seconds. We summarize the clinical applications of anterior segment SS-OCT in Glaucoma. Literature search: We searched PubMed and included Medline using the phrases anterior segment optical coherence tomography in ophthalmology, swept-source OCT, use of AS-OCT in glaucoma, use of swept-source AS-OCT in glaucoma, quantitative assessment of angle, filtering bleb in AS-OCT, comparison of AS-OCT with gonioscopy and comparison of AS-OCT with UBM. Search was made for articles dating 1990 to August 2015.

  14. Performance of the advanced cold neutron source and optics upgrades at the NIST Research Reactor

    International Nuclear Information System (INIS)

    Williams, R.E.; Kopetka, P.; Cook, J.C.; Rowe, J.M.

    2003-01-01

    On March 6, 2002, the NIST Research Reactor resumed routine operation following a six-month shutdown for facility upgrades and maintenance. During the shutdown, the original liquid hydrogen cold neutron source was removed, and the advanced cold source was installed. An optical filter was installed on one of the neutron guides, NG-3, replacing a crystal filter for the 30-m SANS instrument and the guide used between the chopper disks of the Disk Chopper time-of-flight Spectrometer (DCS) installed on NG-4 has been recently reconfigured. Additional improvements in the neutron optics of various instruments are being made. The advanced liquid hydrogen cold neutron source performs as expected, nearly doubling the flux available to most instruments. The measured gains range from about 1.4 at 2 A, to over a factor of two at 15 A. Also as expected, the heat load in the new source increased to 1200 watts, but the previously existing refrigerator has easily accommodated the increase. With intensity gains of a factor of two in the important long wavelength region of the spectrum, the advanced cold source significantly enhances the measurement capability of the cold neutron scattering instrumentation at NIST. The optical filter on NG-3 is also very successful; the 30-m SANS has an additional gain of two at 17 A. A system of refracting lenses and prisms near the SANS sample position has made possible measurements at low Q (0.0005 A -1 ) that were previously not feasible. The DCS has also seen additional intensity gain factors in excess of two for the majority of experiments and at short neutron wavelengths the gains exceed three. In addition, two new triple axis spectrometers will feature double-focusing monochromators in order to exploit the full size of the available thermal and cold neutron beam tubes. The success of the advanced cold source and enhanced neutron optics contributed to the recognition of the NIST Center for Neutron Research as 'the premiere neutron scattering

  15. Advances in broad bandwidth light sources for ultrahigh resolution optical coherence tomography

    International Nuclear Information System (INIS)

    Unterhuber, A; Povazay, B; Bizheva, K; Hermann, B; Sattmann, H; Stingl, A; Le, T; Seefeld, M; Menzel, R; Preusser, M; Budka, H; Schubert, Ch; Reitsamer, H; Ahnelt, P K; Morgan, J E; Cowey, A; Drexler, W

    2004-01-01

    Novel ultra-broad bandwidth light sources enabling unprecedented sub-2 μm axial resolution over the 400 nm-1700 nm wavelength range have been developed and evaluated with respect to their feasibility for clinical ultrahigh resolution optical coherence tomography (UHR OCT) applications. The state-of-the-art light sources described here include a compact Kerr lens mode locked Ti:sapphire laser (λ c = 785 nm, Δλ = 260 nm, P out = 50 mW) and different nonlinear fibre-based light sources with spectral bandwidths (at full width at half maximum) up to 350 nm at λ c = 1130 nm and 470 nm at λ c = 1375 nm. In vitro UHR OCT imaging is demonstrated at multiple wavelengths in human cancer cells, animal ganglion cells as well as in neuropathologic and ophthalmic biopsies in order to compare and optimize UHR OCT image contrast, resolution and penetration depth

  16. Radiation field of an optically finite homogeneous atmosphere with internal sources

    International Nuclear Information System (INIS)

    Viik, T.

    2010-01-01

    The equation of radiative transfer in an optically finite homogeneous atmosphere with different internal sources is solved using the method of kernel approximation the essence of which is to approximate the kernel in the equation for the Sobolev resolvent function by a Gauss-Legendre sum. This approximation allows to solve the equation exactly for the resolvent function while the solution is a weighted sum of exponents. Since the resolvent function is closely connected with the Green function of the integral radiative transfer equation, the radiation field for different internal sources can be found by simple integration. In order to simplify the obtained formulas we have defined the x and y functions as the generalization of the well-known Ambarzumian-Chandrasekhar X and Y functions. For some types of internal sources the package of codes in Fortran-77 can be found at (http://www.aai.ee/~viik/HOMOGEN.FOR).

  17. Imaging choroidal neovascular membrane using en face swept-source optical coherence tomography angiography

    Directory of Open Access Journals (Sweden)

    Moussa M

    2017-10-01

    Full Text Available Magdy Moussa,1,2 Mahmoud Leila,3 Hagar Khalid1,2 1Ophthalmology Department, Faculty of Medicine, Tanta University, Tanta, Egypt; 2MEDIC Eye Center, Tanta, Egypt; 3Retina Department, Research Institute of Ophthalmology, Giza, Egypt Purpose: The aim of this study was to assess the efficacy of swept-source optical coherence tomography angiography (SS-OCTA in delineating the morphology of choroidal neovascular membrane (CNV. Patients and methods: This was a retrospective observational case series reviewing clinical data and fundus fluorescein angiography (FFA, swept-source optical coherence tomography (SS-OCT, and SS-OCTA images of patients with CNV and comparing the findings. The swept-source technology enables deeper penetration and superior axial resolution. The incorporated blood flow detection algorithm, optical coherence tomography angiography ratio analysis (OCTARA, enables visualization of CNV in vivo without the need for dye injection. Results: The study included 136 eyes of 105 patients. Active lesions on SS-OCTA images showed increased capillary density, extensive arborization, vascular anastomosis and looping, and peri-lesional hollow. Inactive lesions showed decreased capillary density, presence of large linear vessels, and presence of feeder vessels supplying the CNV. We detected positive correlation between SS-OCTA, FFA, and SS-OCT images in 97% of eyes. In the remaining 3%, SS-OCTA confirmed the absence of CNV, whereas FFA and SS-OCT either were inconclusive in the diagnosis of CNV or yielded false-positive results. Conclusion: SS-OCT and SS-OCTA represent a reproducible risk-free analog for FFA in imaging CNV. SS-OCTA is particularly versatile in cases where FFA and SS-OCT are inconclusive. Keywords: swept-source OCT, OCT angiography, imaging of CNV, OCTARA algorithm

  18. Optical microscope using an interferometric source of two-color, two-beam entangled photons

    Science.gov (United States)

    Dress, William B.; Kisner, Roger A.; Richards, Roger K.

    2004-07-13

    Systems and methods are described for an optical microscope using an interferometric source of multi-color, multi-beam entangled photons. A method includes: downconverting a beam of coherent energy to provide a beam of multi-color entangled photons; converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; transforming at least a portion of the converged multi-color entangled photon beam by interaction with a sample to generate an entangled photon specimen beam; and combining the entangled photon specimen beam with an entangled photon reference beam within a single beamsplitter. An apparatus includes: a multi-refringent device providing a beam of multi-color entangled photons; a condenser device optically coupled to the multi-refringent device, the condenser device converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; a beam probe director and specimen assembly optically coupled to the condenser device; and a beam splitter optically coupled to the beam probe director and specimen assembly, the beam splitter combining an entangled photon specimen beam from the beam probe director and specimen assembly with an entangled photon reference beam.

  19. Advanced RF and microwave functions based on an integrated optical frequency comb source.

    Science.gov (United States)

    Xu, Xingyuan; Wu, Jiayang; Nguyen, Thach G; Shoeiby, Mehrdad; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J

    2018-02-05

    We demonstrate advanced transversal radio frequency (RF) and microwave functions based on a Kerr optical comb source generated by an integrated micro-ring resonator. We achieve extremely high performance for an optical true time delay aimed at tunable phased array antenna applications, as well as reconfigurable microwave photonic filters. Our results agree well with theory. We show that our true time delay would yield a phased array antenna with features that include high angular resolution and a wide range of beam steering angles, while the microwave photonic filters feature high Q factors, wideband tunability, and highly reconfigurable filtering shapes. These results show that our approach is a competitive solution to implementing reconfigurable, high performance and potentially low cost RF and microwave signal processing functions for applications including radar and communication systems.

  20. Confidence range estimate of extended source imagery acquisition algorithms via computer simulations. [in optical communication systems

    Science.gov (United States)

    Chen, CHIEN-C.; Hui, Elliot; Okamoto, Garret

    1992-01-01

    Spatial acquisition using the sun-lit Earth as a beacon source provides several advantages over active beacon-based systems for deep-space optical communication systems. However, since the angular extend of the Earth image is large compared to the laser beam divergence, the acquisition subsystem must be capable of resolving the image to derive the proper pointing orientation. The algorithms used must be capable of deducing the receiver location given the blurring introduced by the imaging optics and the large Earth albedo fluctuation. Furthermore, because of the complexity of modelling the Earth and the tracking algorithms, an accurate estimate of the algorithm accuracy can only be made via simulation using realistic Earth images. An image simulator was constructed for this purpose, and the results of the simulation runs are reported.

  1. Optics for protein microcrystallography using synchrotron and laboratory X-ray sources

    International Nuclear Information System (INIS)

    Varghese, J.N.; Van Donkelaar, A.; Balaic, D.X.; Barnea, Z.

    2000-01-01

    Full text: For protein crystallography, a highly-intense focused beam overcomes a serious constraint in current biological research: the inability of many protein molecules to form crystals larger than a few tens of microns in size. High structure-resolution X-ray diffraction analysis of microcrystals is currently only being studied at synchrotron X-ray sources. We shall examine how this is being carried out, and also report the development of a novel tapered glass monocapillary toroidal-mirror optic, which achieves a high-intensity, low-divergence focused beam from a rotating-anode Xray generator. We have used this optic, which demonstrates an ∼28x intensity gain at the beam focus to solve the structure of a plant exoglucanse/inhibtor complex microcrystal to 2.8 Angstroms, with volume equivalent to a 30-micron-edge cube

  2. A tunable continuous wave (CW) and short-pulse optical source for THz brain imaging applications

    International Nuclear Information System (INIS)

    Bakopoulos, P; Karanasiou, I; Zakynthinos, P; Uzunoglu, N; Avramopoulos, H; Pleros, N

    2009-01-01

    We demonstrate recent advances toward the development of a novel 2D THz imaging system for brain imaging applications both at the macroscopic and at the bimolecular level. A frequency-synthesized THz source based on difference frequency generation between optical wavelengths is presented, utilizing supercontinuum generation in a highly nonlinear optical fiber with subsequent spectral carving by means of a fiber Fabry–Perot filter. Experimental results confirm the successful generation of THz radiation in the range of 0.2–2 THz, verifying the enhanced frequency tunability properties of the proposed system. Finally, the roadmap toward capturing functional brain information by exploiting THz imaging technologies is discussed, outlining the unique advantages offered by THz frequencies and their complementarity with existing brain imaging techniques

  3. Beam optics study of a negative ion source for neutral beam injection application at ASIPP

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jiang-Long; Liang, Li-Zhen [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Jiang, Cai-Chao [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate school, University of Science and Technology of China, Hefei 230026 (China); Xie, Ya-Hong, E-mail: xieyh@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Chun-Dong; Li, Jun; Gu, Yu-Ming; Chen, Yu-Qian [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Li, Jing-Yong; Wu, Ming-Shan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate school, University of Science and Technology of China, Hefei 230026 (China)

    2017-04-15

    In order to study the generation and extraction of negative ions for neutral beam injection application, a negative ion source is being designed and constructed at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). Through a four electrode grids system inside the accelerator, a negative ion beam will be extracted and accelerated up to −60 kV on a reduced scale extraction area of 12 × 50 cm{sup 2} (the area of PG apertures is 185 cm{sup 2}). The beam optics is a key issue for the accelerator design, and greatly determine the source experimental performance in term of beam current, heat load on the grid, beam divergence, and so on. In this paper, the trajectories of electrons and negative ions were simulated in the electrode grids of the negative ion source. The filter capability of electron deflection magnet on the co-extracted electrons is evaluated and confirmed. The negative ion beam optics was designed according to the calculated results of beam divergence and beam radius along the beamlet in different acceleration voltages. The deflection effect of the electron deflection magnet on the negative ion beam was investigated in the single beamlet case and multi-beamlets case.

  4. Eternal triangle: the interaction of light source, electrical control gear, and optics

    Science.gov (United States)

    S'heeren, Griet

    1998-04-01

    In this particular 'affair' the participants are less than human but have individual personalities they bring to their relationship with each other. High pressure metal halide lamps such as BriteArc lamps have the highest luminance and radiance of all continuously operating practical light source. Since these lamps have short arcs and are available in power ratings from about 30W to 30kW they have found applications with various optical systems. Besides the lamps, such systems include an electrical control device and an optical system. To fulfil the user's requirements for a specific application, it is not only important to choose the right lamp, but crucial to achieve a harmonious marriage between the light source, electrical control device and the optics. To run a high pressure discharge lamp an ignitor/ballast system is essential This stabilizes the lamp parameters. The chemical components inside the lamp determine the lamp voltage and the gear determines, via the current, the lamp power. These are directly related in the luminance and color temperature of the emitted light. Therefore lamp performance and effective life are dependent on the ignitor, control gear and lamp combination. Since the lamp emits radiation in all directions, collection of the light from a lamp can be improved by using reflectors to deliver the light into a lens system. Since lamps with short arc gaps approach a point source they appear ideal for optical system applications. The shape of the reflector and the focusing of the lamp determine which part of the light is collected out of the light-arc. In the case of an LCD projector, the final light output also depends on the transmission characteristics of the LCD panels. Their nonlinearity causes the color of the emitted light to be different from the lamp color. All these parameters have to be optimized to obtain the highest performance. This leads to the conclusion that a carefully matched combination of lamp, ignitor/ballast and optics

  5. XUV synchrotron optical components for the Advanced Light Source: Summary of the requirements and the developmental program

    International Nuclear Information System (INIS)

    McKinney, W.; Irick, S.; Lunt, D.

    1992-07-01

    We give a brief summary of the requirements for water cooled optical components for the Advanced Light Source (ALS), a third generation synchrotron radiation source under construction at Lawrence Berkeley Laboratory (LBL). Materials choices, surface figure and smoothness specifications, and metrology systems for measuring the plated metal surfaces are discussed. Results from a finished water cooled copper alloy mirror will be used to demonstrate the state of the art in optical metrology with the Takacs Long Trace Profiler (LTP II)

  6. Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

    Science.gov (United States)

    Gonzalo, I. B.; Engelsholm, R. D.; Bang, O.

    2018-03-01

    Commercially available silica-fiber-based and ultra-broadband supercontinuum (SC) sources are typically generated by pumping close to the zero-dispersion wavelength (ZDW) of a photonic crystal fiber (PCF), using high-power picosecond or nanosecond laser pulses. Despite the extremely broad bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise (RIN) as a function of the pump pulse duration and fiber length. Furthermore, we experimentally demonstrate the role of the fiber length on the RIN of the ANDi SC, validating the results calculated numerically. In the end, we compare the RIN of a commercial SC source based on MI and the ANDi SC source developed here, which shows better noise performance when it is carefully designed.

  7. Subgingival calculus imaging based on swept-source optical coherence tomography

    Science.gov (United States)

    Hsieh, Yao-Sheng; Ho, Yi-Ching; Lee, Shyh-Yuan; Lu, Chih-Wei; Jiang, Cho-Pei; Chuang, Ching-Cheng; Wang, Chun-Yang; Sun, Chia-Wei

    2011-07-01

    We characterized and imaged dental calculus using swept-source optical coherence tomography (SS-OCT). The refractive indices of enamel, dentin, cementum, and calculus were measured as 1.625 +/- 0.024, 1.534 +/- 0.029, 1.570 +/- 0.021, and 2.097 +/- 0.094, respectively. Dental calculus leads strong scattering properties, and thus, the region can be identified from enamel with SS-OCT imaging. An extracted human tooth with calculus is covered with gingiva tissue as an in vitro sample for tomographic imaging.

  8. HST/ACS IMAGING OF OMEGA CENTAURI: OPTICAL COUNTERPARTS OF CHANDRA X-RAY SOURCES

    International Nuclear Information System (INIS)

    Cool, Adrienne M.; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Haggard, Daryl; Anderson, Jay

    2013-01-01

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central ∼10' × 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, ∼40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M 625 =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in ω Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in ω to Cen 20, the largest number yet known in any globular cluster.

  9. High-order UWB pulses scheme to generate multilevel modulation formats based on incoherent optical sources.

    Science.gov (United States)

    Bolea, Mario; Mora, José; Ortega, Beatriz; Capmany, José

    2013-11-18

    We present a high-order UWB pulses generator based on a microwave photonic filter which provides a set of positive and negative samples by using the slicing of an incoherent optical source and the phase inversion in a Mach-Zehnder modulator. The simple scalability and high reconfigurability of the system permit a better accomplishment of the FCC requirements. Moreover, the proposed scheme permits an easy adaptation to pulse amplitude modulation, bi phase modulation, pulse shape modulation and pulse position modulation. The flexibility of the scheme for being adaptable to multilevel modulation formats permits to increase the transmission bit rate by using hybrid modulation formats.

  10. Infra-red laser source using Tm:Ho optical fibre for potential sensor applications

    International Nuclear Information System (INIS)

    Chen, S Y; Yeo, T L; Leighton, J; Sun, T; Grattan, K T V; Lade, R; Powell, B; Foster-Turner, G; Osborne, M

    2007-01-01

    In this work, a 1600nm Er fibre laser, which demonstrates a high pumping efficiency, has been used to pump an efficient all-fibre Tm:Ho laser system using a 0.3 m length of optical fibre. A low threshold of 33 mW and a slope efficiency of 0.6% have been achieved with operation at a wavelength of ∼1870 nm. A cross-comparison has been made with the output of a device pumped by a 785 nm laser diode. The focus of the work is better and more compact sources for gas sensing in the near infra red region of the spectrum

  11. Point-source reconstruction with a sparse light-sensor array for optical TPC readout

    International Nuclear Information System (INIS)

    Rutter, G; Richards, M; Bennieston, A J; Ramachers, Y A

    2011-01-01

    A reconstruction technique for sparse array optical signal readout is introduced and applied to the generic challenge of large-area readout of a large number of point light sources. This challenge finds a prominent example in future, large volume neutrino detector studies based on liquid argon. It is concluded that the sparse array option may be ruled out for reasons of required number of channels when compared to a benchmark derived from charge readout on wire-planes. Smaller-scale detectors, however, could benefit from this technology.

  12. Post-processing with linear optics for improving the quality of single-photon sources

    International Nuclear Information System (INIS)

    Berry, Dominic W; Scheel, Stefan; Myers, Casey R; Sanders, Barry C; Knight, Peter L; Laflamme, Raymond

    2004-01-01

    Triggered single-photon sources produce the vacuum state with non-negligible probability, but produce a much smaller multiphoton component. It is therefore reasonable to approximate the output of these photon sources as a mixture of the vacuum and single-photon states. We show that it is impossible to increase the probability for a single photon using linear optics and photodetection on fewer than four modes. This impossibility is due to the incoherence of the inputs; if the inputs were pure-state superpositions, it would be possible to obtain a perfect single-photon output. In the more general case, a chain of beam splitters can be used to increase the probability for a single photon, but at the expense of adding an additional multiphoton component. This improvement is robust against detector inefficiencies, but is degraded by distinguishable photons, dark counts or multiphoton components in the input

  13. Operational experience with the TRIUMF optically pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Schmor, P.W.; Buchmann, L.; Jayamanna, K.; Levy, C.D.P.; McDonald, M.; Ruegg, R.

    1991-05-01

    The initial goal of a polarized proton beam extracted from the TRIUMF cyclotron, having a current of 5 μA with 60% polarization, has been achieved with the development of the optically pumped polarized H - ion source. This beam is now being used to produce an intense secondary beam of polarized neutrons for the TRIUMF experimental program. Much of the recent development effort has addressed the reliability requirements for routine operation. This paper describes the results with emphasis on the laser stabilization subsystem, the modifications to the electron cyclotron resonance proton ion source (ECRIS), the sodium charge exchange cells and the development of a low energy polarimeter. Also discussed are the developments which should lead to a higher polarization. (Author) 7 refs

  14. Noninvasive Visualization and Analysis of the Human Parafoveal Capillary Network Using Swept Source OCT Optical Microangiography.

    Science.gov (United States)

    Kuehlewein, Laura; Tepelus, Tudor C; An, Lin; Durbin, Mary K; Srinivas, Sowmya; Sadda, Srinivas R

    2015-06-01

    We characterized the foveal avascular zone (FAZ) and the parafoveal capillary network in healthy subjects using swept source OCT optical microangiography (OMAG). We acquired OMAG images of the macula of 19 eyes (13 healthy individuals) using a prototype swept source laser OCT. En face images of the retinal vasculature were generated for superficial and deep inner retinal layers (SRL/DRL) in regions of interest 250 (ROI-250) and 500 (ROI-500) μm from the FAZ border. The mean area (mm2) of the FAZ was 0.304 ± 0.132 for the SRL and 0.486 ± 0.162 for the DRL (P network at different retinal layers.

  15. Intense source of spin-polarized electrons using laser-induced optical pumping

    International Nuclear Information System (INIS)

    Gray, L.G.; Giberson, K.W.; Cheng, C.; Keiffer, R.S.; Dunning, F.B.; Walters, G.K.

    1983-01-01

    A source of spin-polarized electrons based on a laser-pumped flowing helium afterglow is described. He(2 3 S) atoms contained in the afterglow are optically pumped using circularly polarized 1.08-μm (2 3 S→2 3 P) radiation provided by a NaF (F 2+ )( color-center laser. Spin angular momentum conservation in subsequent chemi-ionization reactions with CO 2 produces polarized electrons that are extracted from the afterglow. At low currents, < or approx. =1 μA, polarizations of approx.70%--80% are achieved. At higher currents the polarization decreases, falling to approx.40% at 50 μA. The spin polarization can be simply reversed (P→-P) and the source is suitable for use in the majority of low-energy spin-dependent scattering experiments proposed to date

  16. Optical and X-ray luminosities of expanding nebulae around ultraluminous X-ray sources

    Science.gov (United States)

    Siwek, Magdalena; Sądowski, Aleksander; Narayan, Ramesh; Roberts, Timothy P.; Soria, Roberto

    2017-09-01

    We have performed a set of simulations of expanding, spherically symmetric nebulae inflated by winds from accreting black holes in ultraluminous X-ray sources (ULXs). We implemented a realistic cooling function to account for free-free and bound-free cooling. For all model parameters we considered, the forward shock in the interstellar medium becomes radiative at a radius ˜100 pc. The emission is primarily in optical and UV, and the radiative luminosity is about 50 per cent of the total kinetic luminosity of the wind. In contrast, the reverse shock in the wind is adiabatic so long as the terminal outflow velocity of the wind vw ≳ 0.003c. The shocked wind in these models radiates in X-rays, but with a luminosity of only ˜1035 erg s-1. For wind velocities vw ≲ 0.001c, the shocked wind becomes radiative, but it is no longer hot enough to produce X-rays. Instead it emits in optical and UV, and the radiative luminosity is comparable to 100 per cent of the wind kinetic luminosity. We suggest that measuring the optical luminosities and putting limits on the X-ray and radio emission from shock-ionized ULX bubbles may help in estimating the mass outflow rate of the central accretion disc and the velocity of the outflow.

  17. An optically stabilized fast-switching light emitting diode as a light source for functional neuroimaging.

    Directory of Open Access Journals (Sweden)

    Daniel A Wagenaar

    Full Text Available Neuroscience research increasingly relies on optical methods for evoking neuronal activity as well as for measuring it, making bright and stable light sources critical building blocks of modern experimental setups. This paper presents a method to control the brightness of a high-power light emitting diode (LED light source to an unprecedented level of stability. By continuously monitoring the actual light output of the LED with a photodiode and feeding the result back to the LED's driver by way of a proportional-integral controller, drift was reduced to as little as 0.007% per hour over a 12-h period, and short-term fluctuations to 0.005% root-mean-square over 10 seconds. The LED can be switched on and off completely within 100 μs, a feature that is crucial when visual stimuli and light for optical recording need to be interleaved to obtain artifact-free recordings. The utility of the system is demonstrated by recording visual responses in the central nervous system of the medicinal leech Hirudo verbana using voltage-sensitive dyes.

  18. Optical observations of LIGO source GW 170817 by the Antarctic Survey Telescopes at Dome A, Antarctica

    Science.gov (United States)

    Hu, Lei; Wu, Xuefeng; Andreoni, Igor; Ashley, Michael C. B.; Cooke, Jeff; Cui, Xiangqun; Du, Fujia; Dai, Zigao; Gu, Bozhong; Hu, Yi; Lu, Haiping; Li, Xiaoyan; Li, Zhengyang; Liang, Ensi; Liu, Liangduan; Ma, Bin; Shang, Zhaohui; Sun, Tianrui; Suntzeff, N. B.; Tao, Charling; Udden, Syed A.; Wang, Lifan; Wang, Xiaofeng; Wen, Haikun; Xiao, Di; Su, Jin; Yang, Ji; Yang, Shihai; Yuan, Xiangyan; Zhou, Hongyan; Zhang, Hui; Zhou, Jilin; Zhu, Zonghong

    2017-10-01

    The LIGO detection of gravitational waves (GW) from merging black holes in 2015 marked the beginning of a new era in observational astronomy. The detection of an electromagnetic signal from a GW source is the critical next step to explore in detail the physics involved. The Antarctic Survey Telescopes (AST3), located at Dome A, Antarctica, is uniquely situated for rapid response time-domain astronomy with its continuous night-time coverage during the austral winter. We report optical observations of the GW source (GW 170817) in the nearby galaxy NGC 4993 using AST3. The data show a rapidly fading transient at around 1 day after the GW trigger, with the i-band magnitude declining from 17.23±0.13 magnitude to 17.72±0.09 magnitude in ˜ 0.8 hour. The brightness and time evolution of the optical transient associated with GW 170817 are broadly consistent with the predictions of models involving merging binary neutron stars. We infer from our data that the merging process ejected about ˜ 10^{-2} solar mass of radioactive material at a speed of up to 30% the speed of light.

  19. OPTiM: Optical projection tomography integrated microscope using open-source hardware and software.

    Science.gov (United States)

    Watson, Thomas; Andrews, Natalie; Davis, Samuel; Bugeon, Laurence; Dallman, Margaret D; McGinty, James

    2017-01-01

    We describe the implementation of an OPT plate to perform optical projection tomography (OPT) on a commercial wide-field inverted microscope, using our open-source hardware and software. The OPT plate includes a tilt adjustment for alignment and a stepper motor for sample rotation as required by standard projection tomography. Depending on magnification requirements, three methods of performing OPT are detailed using this adaptor plate: a conventional direct OPT method requiring only the addition of a limiting aperture behind the objective lens; an external optical-relay method allowing conventional OPT to be performed at magnifications >4x; a remote focal scanning and region-of-interest method for improved spatial resolution OPT (up to ~1.6 μm). All three methods use the microscope's existing incoherent light source (i.e. arc-lamp) and all of its inherent functionality is maintained for day-to-day use. OPT acquisitions are performed on in vivo zebrafish embryos to demonstrate the implementations' viability.

  20. SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY REVEALS INTERNAL LIMITING MEMBRANE PEELING ALTERS DEEP RETINAL VASCULATURE.

    Science.gov (United States)

    Michalewska, Zofia; Nawrocki, Jerzy

    2018-04-30

    To describe morphology of retinal and choroidal vessels in swept-source optical coherence tomography angiography before and after vitrectomy with the temporal inverted internal limiting membrane (ILM) flap technique for full-thickness macular holes. Prospective, observational study of 36 eyes of 33 patients with full-thickness macular holes swept-source optical coherence tomography angiography was performed in patients before and 1 month after vitrectomy. Vitrectomy with the temporal inverted ILM flap technique was performed. In this method, ILM is peeled only at one side of the fovea. An ILM flap is created to cover the macular hole. Comparison of retina vasculature in the areas of ILM peeling vs. no ILM peeling at 1 and 3 months after successful vitrectomy was performed. The study demonstrated lower density of vessels in the deep retinal plexus in the area where ILM was peeled as compared to the rest of the fovea. Visual acuity and central retinal thickness 1 month after surgery correlates with fovea avascular zone diameter in deep retinal layers at the same time point (P = 0.001). This study confirmed that ILM peeling might alter blood flow in deep retinal vessels below the peeling area in the early postoperative period. The area of the fovea avascular zone corresponds to functional results at the same time point.

  1. Fundamental characteristics of a synthesized light source for optical coherence tomography.

    Science.gov (United States)

    Sato, Manabu; Wakaki, Ichiro; Watanabe, Yuuki; Tanno, Naohiro

    2005-05-01

    We describe the fundamental characteristics of a synthesized light source (SLS) consisting of two low-coherence light sources to enhance the spatial resolution for optical coherence tomography (OCT). The axial resolution of OCT is given by half the coherence length of the light source. We fabricated a SLS with a coherence length of 2.3 microm and a side-lobe intensity of 45% with an intensity ratio of LED1:LED2 = 1:0.5 by combining two light sources, LED1, with a central wavelength of 691 nm and a spectral bandwidth of 99 nm, and LED2, with a central wavelength of 882 nm and a spectral bandwidth of 76 nm. The coherence length of 2.3 microm was 56% of the shorter coherence length in the two LEDs, which indicates that the axial resolution is 1.2 microm. The lateral resolution was measured at less than 4.4 microm by use of the phase-shift method and with a test pattern as a sample. The measured rough surfaces of a coin are illustrated and discussed.

  2. Lithographic measurement of EUV flare in the 0.3-NA Micro Exposure Tool optic at the Advanced Light Source

    International Nuclear Information System (INIS)

    Cain, Jason P.; Naulleau, Patrick; Spanos, Costas J.

    2005-01-01

    The level of flare present in a 0.3-NA EUV optic (the MET optic) at the Advanced Light Source at Lawrence Berkeley National Laboratory is measured using a lithographic method. Photoresist behavior at high exposure doses makes analysis difficult. Flare measurement analysis under scanning electron microscopy (SEM) and optical microscopy is compared, and optical microscopy is found to be a more reliable technique. In addition, the measured results are compared with predictions based on surface roughness measurement of the MET optical elements. When the fields in the exposure matrix are spaced far enough apart to avoid influence from surrounding fields and the data is corrected for imperfect mask contrast and aerial image proximity effects, the results match predicted values quite well. The amount of flare present in this optic ranges from 4.7% for 2 (micro)m features to 6.8% for 500 nm features

  3. Planck intermediate results XXXVI. Optical identification and redshifts of Planck SZ sources with telescopes at the Canary Islands observatories

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Arnaud, M.

    2016-01-01

    We present the results of approximately three years of observations of Planck Sunyaev-Zeldovich (SZ) sources with telescopes at the Canary Islands observatories as part of the general optical follow-up programme undertaken by the Planck Collaboration. In total, 78 SZ sources are discussed. Deep-i...

  4. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations (TAToO)

    International Nuclear Information System (INIS)

    Dornic, Damien; Brunner, Jurgen; Basa, Stephane; Al Samarai, Imen; Bertin, Vincent; Boer, Michel; Busto, Jose; Escoffier, Stephanie; Klotz, Alain; Mazure, Alain; Vallage, Bertrand

    2011-01-01

    The ANTARES telescope has the opportunity to detect transient neutrino sources, such as gamma-ray bursts, core-collapse supernovae, flares of active galactic nuclei. In order to enhance the sensitivity to these sources, we have developed a new detection method based on the follow-up by optical telescopes of 'golden' neutrino events, such as neutrino doublets coincident in time and space or single neutrinos of very high energy. The ANTARES collaboration has therefore implemented a very fast on-line reconstruction with a good angular resolution. These characteristics allow us to trigger an optical telescope network. Since February 2009, ANTARES is sending alert triggers once or twice per month to the two 25 cm robotic telescope of TAROT. This optical follow-up of such special events would not only give access to the nature of the sources, but also would improve the sensitivity to transient neutrino sources.

  5. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations (TAToO)

    Energy Technology Data Exchange (ETDEWEB)

    Dornic, Damien, E-mail: dornic@cppm.in2p3.f [CPPM, CNRS/IN2P3-Universite de la Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); IFIC, Edificios Investigacion de Paterna, CSIC-Universitat de Valenciaa, Apdo. de correos 22085, 46071 Valencia (Spain); Brunner, Jurgen [CPPM, CNRS/IN2P3-Universite de la Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Basa, Stephane [LAM, BP8, Traverse du siphon, 13376 Marseille Cedex 12 (France); Al Samarai, Imen; Bertin, Vincent [CPPM, CNRS/IN2P3-Universite de la Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Boer, Michel [OHP, 04870 Saint Michel de l' Observatoire (France); Busto, Jose; Escoffier, Stephanie [CPPM, CNRS/IN2P3-Universite de la Mediterranee, 163 avenue de Luminy, 13288 Marseille Cedex 09 (France); Klotz, Alain [OHP, 04870 Saint Michel de l' Observatoire (France); CESR, Observatiore Midi-Pyrenees, CNRS Universite de Toulouse, BP4346, 31028 Toulouse Cedex 04 (France); Mazure, Alain [LAM, BP8, Traverse du siphon, 13376 Marseille Cedex 12 (France); Vallage, Bertrand [CEA-IRFU, Centre de Saclay, 91191 Gif-sur-Yvette (France)

    2011-01-21

    The ANTARES telescope has the opportunity to detect transient neutrino sources, such as gamma-ray bursts, core-collapse supernovae, flares of active galactic nuclei. In order to enhance the sensitivity to these sources, we have developed a new detection method based on the follow-up by optical telescopes of 'golden' neutrino events, such as neutrino doublets coincident in time and space or single neutrinos of very high energy. The ANTARES collaboration has therefore implemented a very fast on-line reconstruction with a good angular resolution. These characteristics allow us to trigger an optical telescope network. Since February 2009, ANTARES is sending alert triggers once or twice per month to the two 25 cm robotic telescope of TAROT. This optical follow-up of such special events would not only give access to the nature of the sources, but also would improve the sensitivity to transient neutrino sources.

  6. Optical fiber sources and transmission controls for multi-Tb/s systems

    Science.gov (United States)

    Nowak, George Adelbert

    The accelerating demand for bandwidth capacity in backbone links of terrestrial communications systems is projected to exceed 1Tb/s by 2002. Lightwave carrier frequencies and fused-silica optical fibers provide the natural combination of high passband frequencies and low- loss medium to satisfy this evolving demand for bandwidth capacity. This thesis addresses three key technologies for enabling multi-Tb/s optical fiber communication systems. The first technology is a broadband source based on supercontinuum generation in optical fiber. Using a single modelocked laser with output pulsewidths of 0.5psec pulses, we generate in ~2m of dispersion-shifted fiber more that 200nm of spectral continuum in the vicinity of 1550nm that is flat to better than +/- 0.5 dB over more than 60nm. The short fiber length prevents degradation of timing jitter of the seed pulses and preserves coherence of the continuum by inhibiting environmental perturbations and mapping of random noise from the vicinity of the input pulse across the continuum. Through experiments and simulations, we find that the continuum characteristics result from 3rd order dispersion effects on higher-order soliton compression. We determine optimal fiber properties to provide desired continuum broadness and flatness for given input pulsewidth and energy conditions. The second technology is a novel delay-shifted nonlinear optical loop mirror (DS-NOLM) that performs a transmission control function by serving as an intensity filter and frequency compensator for 4ps soliton transmission over 75km of standard dispersion fiber, with 25km spacing between amplifiers, by filtering the dispersive waves and compensating for Raman-induced soliton self-frequency shift. The third technology is all-fiber wavelength conversion employing induced modulational instability. We obtain wavelength conversion over 40nm with a peak conversion efficiency of 28dB using 600mW pump pulses in 720m of high-nonlinearity optical fiber. We show

  7. Open source 3D printers: an appropriate technology for building low cost optics labs for the developing communities

    Science.gov (United States)

    Gwamuri, J.; Pearce, Joshua M.

    2017-08-01

    The recent introduction of RepRap (self-replicating rapid prototyper) 3-D printers and the resultant open source technological improvements have resulted in affordable 3-D printing, enabling low-cost distributed manufacturing for individuals. This development and others such as the rise of open source-appropriate technology (OSAT) and solar powered 3-D printing are moving 3-D printing from an industry based technology to one that could be used in the developing world for sustainable development. In this paper, we explore some specific technological improvements and how distributed manufacturing with open-source 3-D printing can be used to provide open-source 3-D printable optics components for developing world communities through the ability to print less expensive and customized products. This paper presents an open-source low cost optical equipment library which enables relatively easily adapted customizable designs with the potential of changing the way optics is taught in resource constraint communities. The study shows that this method of scientific hardware development has a potential to enables a much broader audience to participate in optical experimentation both as research and teaching platforms. Conclusions on the technical viability of 3-D printing to assist in development and recommendations on how developing communities can fully exploit this technology to improve the learning of optics through hands-on methods have been outlined.

  8. Development of contamination-free x-ray optics for next-generation light sources

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Haruhiko, E-mail: hohashi@spring8.or.jp; Senba, Yasunori; Yumoto, Hirokatsu; Koyama, Takahisa; Miura, Takanori; Kishimoto, Hikaru [JASRI / SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 JAPAN (Japan)

    2016-07-27

    We studied typical forms of contamination on X-ray mirrors that cause degradation of beam quality, investigated techniques to remove the contaminants, and propose methods to eliminate the sources of the contamination. The total amount of carbon-containing substances on various materials in the vicinity of a mirror was measured by thermal desorption-gas chromatography/mass spectrometry and thermal desorption spectroscopy. It was found that cleanliness and ultra-high vacuum techniques are required to produce the contamination-free surfaces that are essential for the propagation of high-quality X-ray beams. The reduction of carbonaceous residue adsorbed on the surfaces, and absorbed into the bulk, of the materials in the vicinity of the mirrors is a key step toward achieving contamination-free X-ray optics.

  9. Fast modal simulation of paraxial optical systems: the MIST open source toolbox

    International Nuclear Information System (INIS)

    Vajente, Gabriele

    2013-01-01

    This paper presents a new approach to the simulation of optical laser systems in the paraxial approximation, with particular applications to interferometric gravitational wave detectors. The method presented here is based on a standard decomposition of the laser field in terms of Hermite–Gauss transverse modes. The innovative feature consists of a symbolic manipulation of the equations describing the field propagation. This approach allows a huge reduction in the computational time, especially when a large number of higher order modes is needed to properly simulate the system. The new algorithm has been implemented in an open source toolbox, called the MIST, based on the MATLAB® environment. The MIST has been developed and is being used in the framework of the design of advanced gravitational wave detectors. Examples from this field of application will be discussed to illustrate the capabilities and performance of the simulation tool. (paper)

  10. Defect inspection of actuator lenses using swept-source optical coherence tomography

    Science.gov (United States)

    Lee, Jaeyul; Shirazi, Muhammad Faizan; Park, Kibeom; Jeon, Mansik; Kim, Jeehyun

    2017-12-01

    Actuator lens industries have gained an enormous interest with the enhancement of various latest communication devices, such as mobile phone and notebooks. The quality of the aforementioned devices can be degraded due to the internal defects of actuator lenses. Therefore, in this study, we implemented swept-source optical coherence tomography (SS-OCT) system to inspect defects of actuator lenses. Owing to the high-resolution of the SS-OCT system, defected foreign substances between the actuator lenses, defective regions of lenses and surface stains were more clearly distinguished through three-dimensional (3D) and two-dimensional (2D) cross-sectional OCT images. Therefore, the implemented SS-OCT system can be considered as a potential application to defect inspection of actuator lens.

  11. Open source acceleration of wave optics simulations on energy efficient high-performance computing platforms

    Science.gov (United States)

    Beck, Jeffrey; Bos, Jeremy P.

    2017-05-01

    We compare several modifications to the open-source wave optics package, WavePy, intended to improve execution time. Specifically, we compare the relative performance of the Intel MKL, a CPU based OpenCV distribution, and GPU-based version. Performance is compared between distributions both on the same compute platform and between a fully-featured computing workstation and the NVIDIA Jetson TX1 platform. Comparisons are drawn in terms of both execution time and power consumption. We have found that substituting the Fast Fourier Transform operation from OpenCV provides a marked improvement on all platforms. In addition, we show that embedded platforms offer some possibility for extensive improvement in terms of efficiency compared to a fully featured workstation.

  12. Swept source optical coherence tomography of objects with arbitrary reflectivity profiles

    Science.gov (United States)

    Mezgebo, Biniyam; Nagib, Karim; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-03-01

    Swept Source optical coherence tomography (SS-OCT) has become a well established imaging modality for both medical and industrial diagnostic applications. A cross-sectional SS-OCT image is obtained by applying an inverse discrete Fourier transform (DFT) to axial interferogram measured in the frequency domain (k-space). Fourier inversion of the obtained interferogram typically produces a potentially overlapping conjugate mirror image, whose overlap could be avoided by restricting the object to have its highest reflectivity at its surface. However, this restriction may not be fulfilled when imaging a very thin object that is placed on a highly reflective surface, or imaging an object containing a contrast agent with high reflectivity. In this paper, we show that oversampling of the SS-OCT signal in k-space would overcome the need for such restriction on the object. Our result is demonstrated using SS-OCT images of Axolotl salamander eggs.

  13. Optical emission spectra of a copper plasma produced by a metal vapour vacuum arc plasma source

    International Nuclear Information System (INIS)

    Yotsombat, B.; Poolcharuansin, P.; Vilaithong, T.; Davydov, S.; Brown, I.G.

    2001-01-01

    Optical emission spectroscopy in the range 200-800 nm was applied for investigation of the copper plasma produced by a metal vapour vacuum arc plasma source. The experiments were conducted for the cases when the plasma was guided by straight and Ω-shaped curved solenoids as well as without solenoids, and also for different vacuum conditions. It was found that, besides singly- and doubly-charged ions, a relatively high concentration of excited neutral copper atoms was present in the plasma. The relative fraction of excited atoms was much higher in the region close to the cathode surface than in the plasma column inside the solenoid. The concentration of excited neutral, singly- and doubly-ionized atoms increased proportionally when the arc current was increased to 400 A. Some weak lines were attributed to more highly ionized copper species and impurities in the cathode material. (author)

  14. Normalized Point Source Sensitivity for Off-Axis Optical Performance Evaluation of the Thirty Meter Telescope

    Science.gov (United States)

    Seo, Byoung-Joon; Nissly, Carl; Troy, Mitchell; Angeli, George

    2010-01-01

    The Normalized Point Source Sensitivity (PSSN) has previously been defined and analyzed as an On-Axis seeing-limited telescope performance metric. In this paper, we expand the scope of the PSSN definition to include Off-Axis field of view (FoV) points and apply this generalized metric for performance evaluation of the Thirty Meter Telescope (TMT). We first propose various possible choices for the PSSN definition and select one as our baseline. We show that our baseline metric has useful properties including the multiplicative feature even when considering Off-Axis FoV points, which has proven to be useful for optimizing the telescope error budget. Various TMT optical errors are considered for the performance evaluation including segment alignment and phasing, segment surface figures, temperature, and gravity, whose On-Axis PSSN values have previously been published by our group.

  15. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Woo June Choi; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

    2014-08-31

    We demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilises 1.3-μm high-speed sweptsource optical coherence tomography (SS-OCT). The swept source is based on a micro-electro-mechanical (MEMS)-tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth, which enables the visualisation of microstructures within a few mm from the skin surface. We show that the skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic. (laser biophotonics)

  16. Volumetric cutaneous microangiography of human skin in vivo by VCSEL swept-source optical coherence tomography

    International Nuclear Information System (INIS)

    Woo June Choi; Wang, R K

    2014-01-01

    We demonstrate volumetric cutaneous microangiography of the human skin in vivo that utilises 1.3-μm high-speed sweptsource optical coherence tomography (SS-OCT). The swept source is based on a micro-electro-mechanical (MEMS)-tunable vertical cavity surface emission laser (VCSEL) that is advantageous in terms of long coherence length over 50 mm and 100 nm spectral bandwidth, which enables the visualisation of microstructures within a few mm from the skin surface. We show that the skin microvasculature can be delineated in 3D SS-OCT images using ultrahigh-sensitive optical microangiography (UHS-OMAG) with a correlation mapping mask, providing a contrast enhanced blood perfusion map with capillary flow sensitivity. 3D microangiograms of a healthy human finger are shown with distinct cutaneous vessel architectures from different dermal layers and even within hypodermis. These findings suggest that the OCT microangiography could be a beneficial biomedical assay to assess cutaneous vascular functions in clinic. (laser biophotonics)

  17. The laser control system for the TRIUMF optically pumped polarized H- ion source

    International Nuclear Information System (INIS)

    Kadantsev, S.G.; Levy, C.D.P.; Mouat, M.M.

    1994-08-01

    The optically pumped polarized H - ion source at TRIUMF produces up to 100 μΑ dc of 78% polarized beam within an emittance of 1.0 π mm mrad and is now being prepared for an upcoming experiment at TRIUMF that will measure parity violation in pp scattering at 230 MeV. The optical pumping is accomplished by argon laser pumped Ti-sapphire lasers. The laser control system provides monitoring and precision control of the lasers for fast spin reversal up to 200 s -1 . To solve the problems of laser power and frequency stabilization during fast spin flipping, techniques and algorithms have been developed that significantly reduce the variation of laser frequency and power between spin states. The upgraded Faraday rotation system allows synchronous measurement of Rb thickness and polarization while spin flipping. The X Window environment provides both local and remote control to laser operators via a local area network and X window terminals. In this new environment issues such as access authorization, response time, operator interface consistency and ease of use are of particular importance. (author)

  18. In situ focus characterization by ablation technique to enable optics alignment at an XUV FEL source

    Czech Academy of Sciences Publication Activity Database

    Gerasimova, N.; Dziarzhytski, S.; Weigelt, H.; Chalupský, Jaromír; Hájková, Věra; Vyšín, Luděk; Juha, Libor

    2013-01-01

    Roč. 84, č. 6 (2013), "065104-1"-"065104-6" ISSN 0034-6748 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE.2.3.20.0087; GA ČR(CZ) GAP108/11/1312; GA ČR GAP205/11/0571; GA MŠk EE2.3.30.0057; GA MŠk(CZ) LG13029; GA ČR GAP208/10/2302; GA ČR GA13-28721S Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OP VK 2 LaserGen(XE) CZ.1.07/2.3.00/20.0087; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057; AVČR(CZ) M100101221 Institutional support: RVO:68378271 Keywords : free electron lasers * laser ablation * laser beams * optical focusing * ultraviolet sources Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.584, year: 2013

  19. A Search for Optical Counterparts of Chandra Sources in Omega Centauri using ACS

    Science.gov (United States)

    Haggard, D.; Fuller, A. D.; Dorfman, J. L.; Cool, A. M.; Anderson, J.; Edmonds, P. D.; Davies, M. B.

    2002-12-01

    The globular cluster Omega Centauri, with its high mass and large, moderate density core, is of interest both for its population of primordial binaries and for the large number of tidal-capture and/or exchange-collision binaries it may harbor. We have obtained a 3x3 mosaic of Wide Field Camera pointings with HST's Advanced Camera for Surveys, covering a 10'x10' field out to the cluster's half-mass radius. Containing ~1.7 million detected stars, the resulting mosaic represents the most complete image of Omega Cen yet obtained. Here we report preliminary findings of a search in these data for optical counterparts to more than 100 faint X-ray sources (Lx ~ 2 x 1030 - 5 x 1032 erg-s-1) detected in our prior study of Omega Cen using the Chandra X-ray Observatory. Cluster X-ray sources are likely to consist primarily of accreting binary stars and close detached binaries with active coronae. Significant numbers of active galaxies in the background are also expected to be present. Using B, R, and H-alpha images, we are searching for optical counterparts that are H-alpha-bright and blue, as signatures of accretion in cataclysmic variables and/or quiescent low-mass X-ray binaries. Active binaries (e.g., BY Draconis stars) may appear as weaker H-alpha emitters lying on or slightly redward of the main sequence. This work is supported by NASA grant GO-9442 from the Space Telescope Science Institute.

  20. Optical studies of X-ray sources with the MASCOT - a charge-coupled device /CCD/-based astronomical instrument

    International Nuclear Information System (INIS)

    Ricker, G.R.; Bautz, M.W.; Dewey, D.; Meyer, S.S.

    1981-01-01

    The performance levels achieved by the MASCOT (MIT Astronomical Spectrometer/Camera for Optical Telescopes) on the 1.3-m telescope at the McGraw-Hill observatory in March 1981 are discussed along with preliminary data obtained in searches for optical counterparts to four 'empty-field' X-ray sources. In the W band (4000-7000 A), the MASCOT achieved a sky-limited sensitivity of +24.4 mag per sq arcsec in an 1800 s integration. The ability to flatten pictures to a level consistent with (sky + source) photon statistics and readout noise was demonstrated. For the four sources observed, an optical counterpart was established for one source (1413+13) based on positional coincidence (better than 1.8 arcsec), four possible candidates were detected in the error box of another source (1009 35) and upper sensitivity limits were established for optical counterparts in the error boxes for the other two sources (0920+39 and 0931-11)

  1. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Source For System-Level Testing Of Optical Sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2016-01-01

    In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance.

  2. Construction of a single/multiple wavelength RZ optical pulse source at 40 GHz by use of wavelength conversion in a high-nonlinearity DSF-NOLM

    DEFF Research Database (Denmark)

    Yu, Jianjun; Yujun, Qian; Jeppesen, Palle

    2001-01-01

    A single or multiple wavelength RZ optical pulse source at 40 GHz is successfully obtained by using wavelength conversion in a nonlinear optical loop mirror consisting of high nonlinearity-dispersion shifted fiber.......A single or multiple wavelength RZ optical pulse source at 40 GHz is successfully obtained by using wavelength conversion in a nonlinear optical loop mirror consisting of high nonlinearity-dispersion shifted fiber....

  3. Error-source effects on the performance of direct and iterative algorithms on an optical matrix-vector processor

    Science.gov (United States)

    Perlee, Caroline J.; Casasent, David P.

    1990-09-01

    Error sources in an optical matrix-vector processor are analyzed in terms of their effect on the performance of the algorithms used to solve a set of nonlinear and linear algebraic equations. A direct and an iterative algorithm are used to solve a nonlinear time-dependent case-study from computational fluid dynamics. A simulator which emulates the data flow and number representation of the OLAP is used to studs? these error effects. The ability of each algorithm to tolerate or correct the error sources is quantified. These results are extended to the general case of solving nonlinear and linear algebraic equations on the optical system.

  4. Real-time speckle variance swept-source optical coherence tomography using a graphics processing unit.

    Science.gov (United States)

    Lee, Kenneth K C; Mariampillai, Adrian; Yu, Joe X Z; Cadotte, David W; Wilson, Brian C; Standish, Beau A; Yang, Victor X D

    2012-07-01

    Advances in swept source laser technology continues to increase the imaging speed of swept-source optical coherence tomography (SS-OCT) systems. These fast imaging speeds are ideal for microvascular detection schemes, such as speckle variance (SV), where interframe motion can cause severe imaging artifacts and loss of vascular contrast. However, full utilization of the laser scan speed has been hindered by the computationally intensive signal processing required by SS-OCT and SV calculations. Using a commercial graphics processing unit that has been optimized for parallel data processing, we report a complete high-speed SS-OCT platform capable of real-time data acquisition, processing, display, and saving at 108,000 lines per second. Subpixel image registration of structural images was performed in real-time prior to SV calculations in order to reduce decorrelation from stationary structures induced by the bulk tissue motion. The viability of the system was successfully demonstrated in a high bulk tissue motion scenario of human fingernail root imaging where SV images (512 × 512 pixels, n = 4) were displayed at 54 frames per second.

  5. Electromagnetic diagnostics of ECR-Ion Sources plasmas: optical/X-ray imaging and spectroscopy

    Science.gov (United States)

    Mascali, D.; Castro, G.; Altana, C.; Caliri, C.; Mazzaglia, M.; Romano, F. P.; Leone, F.; Musumarra, A.; Naselli, E.; Reitano, R.; Torrisi, G.; Celona, L.; Cosentino, L. G.; Giarrusso, M.; Gammino, S.

    2017-12-01

    Magnetoplasmas in ECR-Ion Sources are excited from gaseous elements or vapours by microwaves in the range 2.45-28 GHz via Electron Cyclotron Resonance. A B-minimum, magnetohydrodynamic stable configuration is used for trapping the plasma. The values of plasma density, temperature and confinement times are typically ne= 1011-1013 cm-3, 01 eVSilicon Drift detectors with high energy resolution of 125 eV at 5.9 keV have been used for the characterization of plasma emission at 02optical range and spectroscopic measurements have been carried out. Relative abundances of H/H2 atoms/molecules in the plasmas have been measured for different values of neutral pressure, microwave power and magnetic field profile (they are critical for high-power proton sources).

  6. Deep Rapid Optical Follow-Up of Gravitational Wave Sources with the Dark Energy Camera

    Science.gov (United States)

    Cowperthwaite, Philip

    2018-01-01

    The detection of an electromagnetic counterpart associated with a gravitational wave detection by the Advanced LIGO and VIRGO interferometers is one of the great observational challenges of our time. The large localization regions and potentially faint counterparts require the use of wide-field, large aperture telescopes. As a result, the Dark Energy Camera, a 3.3 sq deg CCD imager on the 4-m Blanco telescope at CTIO in Chile is the most powerful instrument for this task in the Southern Hemisphere. I will report on the results from our joint program between the community and members of the dark energy survey to conduct rapid and efficient follow-up of gravitational wave sources. This includes systematic searches for optical counterparts, as well as developing an understanding of contaminating sources on timescales not normally probed by traditional untargeted supernova surveys. I will additionally comment on the immense science gains to be made by a joint detection and discuss future prospects from the standpoint of both next generation wide-field telescopes and next generation gravitational wave detectors.

  7. Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

    Science.gov (United States)

    Bradu, Adrian; Jackson, David A.; Podoleanu, Adrian

    2018-03-01

    Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an "in-house" swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

  8. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

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

  9. Optical design of an x-ray absorption spectroscopy beamline at Indus-2 synchrotron radiation source

    International Nuclear Information System (INIS)

    Das, N.C.; Jha, S.N.; Roy, A.P.

    1999-10-01

    Details of optical design of EXAFS beamline at Indus-2 SRS, under development at CAT, Indore, have been discussed in this report. This beamline will cover the photon energy range of 5 keV to 20 keV and will use a bent crystal of Si(111) having 2d value equal to 6.2709 A. It will accept a horizontal divergence of 1.5 mrad. The heart of the beamline is the bent crystal polychromator which will disperse and focus the synchrotron beam at the experimental sample position. The transmitted radiation from the sample will be, subsequently, detected by a position sensitive detector (CCD type). The detector length is 25 mm. Assuming a suitable value for the distance between the source and the crystal, we have computed several geometrical parameters of the beamline, such as, Bragg angle, crystal length, crystal radius, crystal to sample distance, sample to detector distance, etc. for three different photon energies, namely, 5 keV, 10 keV, and 20 keV. The band passes around these photon energies are 0.3 keV, 1 keV and 2 keV respectively. It has been found that computed geometrical parameters are well within acceptable limits. An extensive ray tracing work was done using the software program SHADOW to evaluate the imaging properties of the beamline. It was established that the image spot size at the sample position improved substantially when the crystal is changed from spherical cylinder shape to elliptic cylinder shape. From the ray intensity plots, the average resolution of the crystal bender was estimated to be 1 eV per channel. Finally based on the optical layout of the beamline, a schematic mechanical layout of the beamline has been prepared. (author)

  10. Evaluation of focal choroidal excavation in the macula using swept-source optical coherence tomography.

    Science.gov (United States)

    Lim, F P M; Loh, B K; Cheung, C M G; Lim, L S; Chan, C M; Wong, D W K

    2014-09-01

    To evaluate imaging findings of patients with focal choroidal excavation (FCE) in the macula using swept-source optical coherence tomography (SS-OCT) and correlate it clinically. Prospective observational case series. Eleven consecutive patients (12 eyes) with FCE were described. Data on demographics and clinical presentation were collected and imaging findings (including color photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and SS-OCT) were analyzed. The primary diagnosis was epiretinal membrane (two eyes), choroidal neovascularization (one eye), polypoidal choroidal vasculopathy (three eyes), central serous chorioretinopathy (one eye), and dry age-related macular degeneration (two eyes). Eleven out of 12 of the lesions were conforming. One presented with a non-conforming lesion that progressed to a conforming lesion. One eye had multiFCE and two had two overlapping choroidal excavations. Using the SS-OCT, we found the choroid to be thinned out at the area of FCE but sclera remained normal. The choroidal tissue beneath the FCE was abnormal, with high internal reflectivity and poor visualization of choroidal vessels. There was loss of contour of the outer choroidal boundary that appeared to be pulled inward by this abnormal choroidal tissue. A suprachoroidal space was noted beneath this choroidal tissue and the choroidal-scleral interface was smooth. Repeat SS-OCT 6 months after presentation showed the area of excavation to be stable in size. FCE can be associated with epiretinal membrane, central serous chorioretinopathy, and age-related macular degeneration. The choroid was thinned out in the area of FCE.

  11. Evaluation of focal choroidal excavation in the macula using swept-source optical coherence tomography

    Science.gov (United States)

    Lim, F P M; Loh, B K; Cheung, C M G; Lim, L S; Chan, C M; Wong, D W K

    2014-01-01

    Purpose To evaluate imaging findings of patients with focal choroidal excavation (FCE) in the macula using swept-source optical coherence tomography (SS-OCT) and correlate it clinically. Methods Prospective observational case series. Eleven consecutive patients (12 eyes) with FCE were described. Data on demographics and clinical presentation were collected and imaging findings (including color photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and SS-OCT) were analyzed. Results The primary diagnosis was epiretinal membrane (two eyes), choroidal neovascularization (one eye), polypoidal choroidal vasculopathy (three eyes), central serous chorioretinopathy (one eye), and dry age-related macular degeneration (two eyes). Eleven out of 12 of the lesions were conforming. One presented with a non-conforming lesion that progressed to a conforming lesion. One eye had multiFCE and two had two overlapping choroidal excavations. Using the SS-OCT, we found the choroid to be thinned out at the area of FCE but sclera remained normal. The choroidal tissue beneath the FCE was abnormal, with high internal reflectivity and poor visualization of choroidal vessels. There was loss of contour of the outer choroidal boundary that appeared to be pulled inward by this abnormal choroidal tissue. A suprachoroidal space was noted beneath this choroidal tissue and the choroidal–scleral interface was smooth. Repeat SS-OCT 6 months after presentation showed the area of excavation to be stable in size. Conclusion FCE can be associated with epiretinal membrane, central serous chorioretinopathy, and age-related macular degeneration. The choroid was thinned out in the area of FCE. PMID:24946847

  12. Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror.

    Science.gov (United States)

    Lu, Chen D; Kraus, Martin F; Potsaid, Benjamin; Liu, Jonathan J; Choi, Woojhon; Jayaraman, Vijaysekhar; Cable, Alex E; Hornegger, Joachim; Duker, Jay S; Fujimoto, James G

    2013-12-20

    We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging region on the retina. Volumetric and high definition scans were obtained from 5 undilated normal subjects. Volumetric OCT data was acquired by scanning the 2.4 mm diameter 2D MEMS mirror sinusoidally in the fast direction and linearly in the orthogonal slow direction. A second volumetric sinusoidal scan was obtained in the orthogonal direction and the two volumes were processed with a software algorithm to generate a merged motion-corrected volume. Motion-corrected standard 6 x 6 mm(2) and wide field 10 x 10 mm(2) volumetric OCT data were generated using two volumetric scans, each obtained in 1.4 seconds. High definition 10 mm and 6 mm B-scans were obtained by averaging and registering 25 B-scans obtained over the same position in 0.57 seconds. One of the advantages of volumetric OCT data is the generation of en face OCT images with arbitrary cross sectional B-scans registered to fundus features. This technology should enable screening applications to identify early retinal disease, before irreversible vision impairment or loss occurs. Handheld OCT technology also promises to enable applications in a wide range of settings outside of the traditional ophthalmology or optometry clinics including pediatrics, intraoperative, primary care, developing countries, and military medicine.

  13. Low Noise Frequency Comb Sources Based on Synchronously Pumped Doubly Resonant Optical Parametric Oscillators

    Science.gov (United States)

    Wan, Chenchen

    Optical frequency combs are coherent light sources consist of thousands of equally spaced frequency lines. Frequency combs have achieved success in applications of metrology, spectroscopy and precise pulse manipulation and control. The most common way to generate frequency combs is based on mode-locked lasers which has the output spectrum of comb structures. To generate stable frequency combs, the output from mode-locked lasers need to be phase stabilized. The whole comb lines will be stabilized if the pulse train repetition rate corresponding to comb spacing and the pulse carrier envelope offset (CEO) frequency are both stabilized. The output from a laser always has fluctuations in parameters known as noise. In laser applications, noise is an important factor to limit the performance and often need to be well controlled. For example in precision measurement such as frequency metrology and precise spectroscopy, low laser intensity and phase noise is required. In mode-locked lasers there are different types of noise like intensity noise, pulse temporal position noise also known as timing jitter, optical phase noise. In term for frequency combs, these noise dynamics is more complex and often related. Understanding the noise behavior is not only of great interest in practical applications but also help understand fundamental laser physics. In this dissertation, the noise of frequency combs and mode-locked lasers will be studied in two projects. First, the CEO frequency phase noise of a synchronously pumped doubly resonant optical parametric oscillators (OPO) will be explored. This is very important for applications of the OPO as a coherent frequency comb source. Another project will focus on the intensity noise coupling in a soliton fiber oscillator, the finding of different noise coupling in soliton pulses and the dispersive waves generated from soliton perturbation can provide very practical guidance for low noise soliton laser design. OPOs are used to generate

  14. The optical, infrared and radio properties of extragalactic sources observed by SDSS, 2mass and first surveys

    International Nuclear Information System (INIS)

    Z. Ivezic et al.

    2002-01-01

    We positionally match sources observed by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. Practically all 2MASS sources are matched to an SDSS source within 2 arcsec; ∼ 11% of them are optically resolved galaxies and the rest are dominated by stars. About 1/3 of FIRST sources are matched to an SDSS source within 2 arcsec; ∼ 80% of these are galaxies and the rest are dominated by quasars. Based on these results, we project that by the completion of these surveys the matched samples will include about 10 7 and 10 6 galaxies observed by both SDSS and 2MASS, and about 250,000 galaxies and 50,000 quasars observed by both SDSS and FIRST. Here we present a preliminary analysis of the optical, infrared and radio properties for the extragalactic sources from the matched samples. In particular, we find that the fraction of quasars with stellar colors missed by the SDSS spectroscopic survey is probably not larger than ∼ 10%, and that the optical colors of radio-loud quasars are ∼ 0.05 mag. redder (with 4σ significance) than the colors of radio-quiet quasars

  15. Simulation of Terahertz Frequency Sources. Polar-Optical Phonon Enhancement of Harmonic Generation in Schottky Diodes

    National Research Council Canada - National Science Library

    Gelmont, Boris

    2002-01-01

    ... polar optical vibration frequency When a high frequency input signal is applied to a frequency multiplier device polar-optical phonons can enhance the non-linearities inherent in this device, enabling...

  16. High heat load x-ray optics research and development at the Advanced Photon Source -- An overview

    International Nuclear Information System (INIS)

    Lee, Wah-Keat; Mills, D.M.

    1993-09-01

    Insertion devices at third generation synchrotron radiation sources such as the APS are capable of producing x-ray beams with total power in excess of 7 kilowatts or power densities of 150 watts/mm 2 at a typical location of the optical components. Optical elements subjected to these types of heat fluxes will suffer considerably unless carefully designed to withstand these unprecedented power loadings. At the Advanced Photon Source (APS), we have an aggressive R ampersand D program aimed at investigating possible methods to mitigate thermal distortions. The approaches being studied include, improved heat exchangers, use of liquid gallium and liquid nitrogen as coolants, novel crystal geometries, power filtering, and replacement of silicon with diamond for crystal monochromators. This paper will provide an overview of the high heat load x-ray optics program at the APS

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-27

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

  18. Optical Tooling and its Uses at the Spallation Neutron Source (SNS)

    CERN Document Server

    Helus, Scott; Error, Joseph; Fazekas, Julius; Maines, James

    2005-01-01

    Optical tooling has been a mainstay of the accelerator alignment community for decades. Even now in the age of electronic survey equipment, optical tooling remains a viable alternative, and at times the only alternative. At SNS, we combine traditional optical tooling alignment methods, instrumentation, and techniques, with the more modern electronic techniques. This paper deals with the integration of optical tooling into the electronic survey world.

  19. Research and development on optically pumped polarized ion sources. Technical progress report, February 1, 1985-January 31, 1986

    International Nuclear Information System (INIS)

    Anderson, L.W.

    1985-07-01

    During the past year we have studied the relaxation times in an optically pumped 23 Na vapor target, studied the effects of radiation trapping on the polarization in a Na vapor target, and have studied the effects of spin exchange collisions on a beam of fast H 0 atoms as they pass through a polarized alkali target. This research is directed toward improvements in the optically pumped Na or other alkali vapor targets used for the production of polarized H - ions. In this progress report we review the properties of the optically pumped polarized H - ion source as well as discussing the progress of our research on optically pumped Na or other alkali vapor targets. 81 refs., 9 figs

  20. Modelling single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources

    NARCIS (Netherlands)

    Loch, R.A.; Sobierajski, R.; Louis, Eric; Bosgra, J.; Bosgra, J.; Bijkerk, Frederik

    2012-01-01

    The single shot damage thresholds of multilayer optics for highintensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly

  1. VISUALIZATION FROM INTRAOPERATIVE SWEPT-SOURCE MICROSCOPE-INTEGRATED OPTICAL COHERENCE TOMOGRAPHY IN VITRECTOMY FOR COMPLICATIONS OF PROLIFERATIVE DIABETIC RETINOPATHY.

    Science.gov (United States)

    Gabr, Hesham; Chen, Xi; Zevallos-Carrasco, Oscar M; Viehland, Christian; Dandrige, Alexandria; Sarin, Neeru; Mahmoud, Tamer H; Vajzovic, Lejla; Izatt, Joseph A; Toth, Cynthia A

    2018-01-10

    To evaluate the use of live volumetric (4D) intraoperative swept-source microscope-integrated optical coherence tomography in vitrectomy for proliferative diabetic retinopathy complications. In this prospective study, we analyzed a subgroup of patients with proliferative diabetic retinopathy complications who required vitrectomy and who were imaged by the research swept-source microscope-integrated optical coherence tomography system. In near real time, images were displayed in stereo heads-up display facilitating intraoperative surgeon feedback. Postoperative review included scoring image quality, identifying different diabetic retinopathy-associated pathologies and reviewing the intraoperatively documented surgeon feedback. Twenty eyes were included. Indications for vitrectomy were tractional retinal detachment (16 eyes), combined tractional-rhegmatogenous retinal detachment (2 eyes), and vitreous hemorrhage (2 eyes). Useful, good-quality 2D (B-scans) and 4D images were obtained in 16/20 eyes (80%). In these eyes, multiple diabetic retinopathy complications could be imaged. Swept-source microscope-integrated optical coherence tomography provided surgical guidance, e.g., in identifying dissection planes under fibrovascular membranes, and in determining residual membranes and traction that would benefit from additional peeling. In 4/20 eyes (20%), acceptable images were captured, but they were not useful due to high tractional retinal detachment elevation which was challenging for imaging. Swept-source microscope-integrated optical coherence tomography can provide important guidance during surgery for proliferative diabetic retinopathy complications through intraoperative identification of different complications and facilitation of intraoperative decision making.

  2. Optimization of ion-optics system for x-ray quasi-monochromatic source on the basis of electrostatic accelerator

    Directory of Open Access Journals (Sweden)

    S. O. Vershynskyi

    2010-06-01

    Full Text Available Ion-optics system with two doublets of electrostatic quadrupole lenses for X-ray quasimonochromatic source was selected. Two variants of lens excitation for stigmatic focusing with two and four independent power supplies are considered. It is shown that using of four independent power supplies leads to improvement of focused ion beam parameters at converter.

  3. Determination of Cr, Mn, Si, and Ni in carbon steels by optical emission spectrometry with spark source

    International Nuclear Information System (INIS)

    Garcia Gonzalez, M.A.; Pomares Alfonso, M.; Mora Lopez, L.

    1995-01-01

    Elemental composition of steels determines some important of his characteristic moreover it is necessary to obtain their quality certification. Analytical procedure has performed for determination of Cr, Mn, Si and Ni in carbon steels by optical emission spectrometry with spark source. reproducibility of results is 5-11 %. Exactitude has tested with results that have obtained by internationally recognised methods-

  4. Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Thrane, Lars; Andersen, Peter E.

    2009-01-01

    We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance...

  5. 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

  6. CENTRAL WAVELENGTH ADJUSTMENT OF LIGHT EMITTING SOURCE IN INTERFEROMETRIC SENSORS BASED ON FIBER-OPTIC BRAGG GRATINGS

    Directory of Open Access Journals (Sweden)

    A. S. Aleynik

    2015-09-01

    Full Text Available The paper is focused on the investigation of fiber-optic interferometric sensor based on the array of fiber Bragg gratings. Reflection spectra displacement mechanism of the fiber Bragg gratings under the external temperature effects and the static pressure is described. The experiment has shown that reflection spectra displacement of Bragg gratings reduces the visibility of the interference pattern. A method of center wavelength adjustment is proposed for the optical radiation source in accord ance with the current Bragg gratings reflection spectra based on the impulse relative modulation of control signal for the Peltier element controller. The semiconductor vertical-cavity surface-emitting laser controlled by a pump driver is used as a light source. The method is implemented by the Peltier element controller regulating and stabilizing the light source temperature, and a programmable logic-integrated circuit monitoring the Peltier element controller. The experiment has proved that the proposed method rendered possible to regulate the light source temperature at a pitch of 0.05 K and adjust the optical radiation source center wavelength at a pitch of 0.05 nm. Experimental results have revealed that the central wavelength of the radiation adjustment at a pitch of 0.005 nm gives the possibility for the capacity of the array consisting of four opticalfiber sensors based on the fiber Bragg gratings. They are formed in one optical fiber under the Bragg grating temperature change from 0° C to 300° C and by the optical fiber mechanical stretching by the force up to 2 N.

  7. Maximum-likelihood-based extended-source spatial acquisition and tracking for planetary optical communications

    Science.gov (United States)

    Tsou, Haiping; Yan, Tsun-Yee

    1999-04-01

    This paper describes an extended-source spatial acquisition and tracking scheme for planetary optical communications. This scheme uses the Sun-lit Earth image as the beacon signal, which can be computed according to the current Sun-Earth-Probe angle from a pre-stored Earth image or a received snapshot taken by other Earth-orbiting satellite. Onboard the spacecraft, the reference image is correlated in the transform domain with the received image obtained from a detector array, which is assumed to have each of its pixels corrupted by an independent additive white Gaussian noise. The coordinate of the ground station is acquired and tracked, respectively, by an open-loop acquisition algorithm and a closed-loop tracking algorithm derived from the maximum likelihood criterion. As shown in the paper, the optimal spatial acquisition requires solving two nonlinear equations, or iteratively solving their linearized variants, to estimate the coordinate when translation in the relative positions of onboard and ground transceivers is considered. Similar assumption of linearization leads to the closed-loop spatial tracking algorithm in which the loop feedback signals can be derived from the weighted transform-domain correlation. Numerical results using a sample Sun-lit Earth image demonstrate that sub-pixel resolutions can be achieved by this scheme in a high disturbance environment.

  8. Optically pumped semiconductor lasers: Conception and characterization of a single mode source for Cesium atoms manipulation

    International Nuclear Information System (INIS)

    Cocquelin, B.

    2009-02-01

    Lasers currently used in atomic clocks or inertial sensors are suffering from a lack of power, narrow linewidth or compactness for future spatial missions. Optically pumped semiconductor lasers, which combine the approach of classical solid state lasers and the engineering of semiconductor laser, are considered here as a candidate to a metrological laser source dedicated to the manipulation of Cesium atoms in these instruments. These lasers have demonstrated high power laser emission in a circular single transverse mode, as well as single longitudinal mode emission, favoured by the semiconductor structure and the external cavity design. We study the definition and the characterization of a proper semiconductor structure for the cooling and the detection of Cesium atoms at 852 nm. A compact and robust prototype tunable on the Cesium D2 hyperfine structure is built. The laser frequency is locked to an atomic transition thanks to a saturated absorption setup. The emission spectral properties are investigated, with a particular attention to the laser frequency noise and the laser linewidth. Finally, we describe and model the thermal properties of the semiconductor structure, which enables the simulation of the laser power characteristic. The experimental parameters are optimised to obtain the maximum output power with our structure. Thanks to our analysis, we propose several ways to overcome these limitations, by reducing the structure heating. (authors)

  9. Longitudinal study of arteriogenesis with swept source optical coherence tomography and hyperspectral imaging

    Science.gov (United States)

    Poole, Kristin M.; Patil, Chetan A.; Nelson, Christopher E.; McCormack, Devin R.; Madonna, Megan C.; Duvall, Craig L.; Skala, Melissa C.

    2014-03-01

    Peripheral arterial disease (PAD) is an atherosclerotic disease of the extremities that leads to high rates of myocardial infarction and stroke, increased mortality, and reduced quality of life. PAD is especially prevalent in diabetic patients, and is commonly modeled by hind limb ischemia in mice to study collateral vessel development and test novel therapies. Current techniques used to assess recovery cannot obtain quantitative, physiological data non-invasively. Here, we have applied hyperspectral imaging and swept source optical coherence tomography (OCT) to study longitudinal changes in blood oxygenation and vascular morphology, respectively, intravitally in the diabetic mouse hind limb ischemia model. Additionally, recommended ranges for controlling physiological variability in blood oxygenation with respect to respiration rate and body core temperature were determined from a control animal experiment. In the longitudinal study with diabetic mice, hyperspectral imaging data revealed the dynamics of blood oxygenation recovery distally in the ischemic footpad. In diabetic mice, there is an early increase in oxygenation that is not sustained in the long term. Quantitative analysis of vascular morphology obtained from Hessian-filtered speckle variance OCT volumes revealed temporal dynamics in vascular density, total vessel length, and vessel diameter distribution in the adductor muscle of the ischemic limb. The combination of hyperspectral imaging and speckle variance OCT enabled acquisition of novel functional and morphological endpoints from individual animals, and provides a more robust platform for future preclinical evaluations of novel therapies for PAD.

  10. Scaled nonuniform Fourier transform for image reconstruction in swept source optical coherence tomography

    Science.gov (United States)

    Mezgebo, Biniyam; Nagib, Karim; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-02-01

    Swept Source optical coherence tomography (SS-OCT) is an important imaging modality for both medical and industrial diagnostic applications. A cross-sectional SS-OCT image is obtained by applying an inverse discrete Fourier transform (DFT) to axial interferograms measured in the frequency domain (k-space). This inverse DFT is typically implemented as a fast Fourier transform (FFT) that requires the data samples to be equidistant in k-space. As the frequency of light produced by a typical wavelength-swept laser is nonlinear in time, the recorded interferogram samples will not be uniformly spaced in k-space. Many image reconstruction methods have been proposed to overcome this problem. Most such methods rely on oversampling the measured interferogram then use either hardware, e.g., Mach-Zhender interferometer as a frequency clock module, or software, e.g., interpolation in k-space, to obtain equally spaced samples that are suitable for the FFT. To overcome the problem of nonuniform sampling in k-space without any need for interferogram oversampling, an earlier method demonstrated the use of the nonuniform discrete Fourier transform (NDFT) for image reconstruction in SS-OCT. In this paper, we present a more accurate method for SS-OCT image reconstruction from nonuniform samples in k-space using a scaled nonuniform Fourier transform. The result is demonstrated using SS-OCT images of Axolotl salamander eggs.

  11. Swept source optical coherence tomography for quantitative and qualitative assessment of dental composite restorations

    Science.gov (United States)

    Sadr, Alireza; Shimada, Yasushi; Mayoral, Juan Ricardo; Hariri, Ilnaz; Bakhsh, Turki A.; Sumi, Yasunori; Tagami, Junji

    2011-03-01

    The aim of this work was to explore the utility of swept-source optical coherence tomography (SS-OCT) for quantitative evaluation of dental composite restorations. The system (Santec, Japan) with a center wavelength of around 1300 nm and axial resolution of 12 μm was used to record data during and after placement of light-cured composites. The Fresnel phenomenon at the interfacial defects resulted in brighter areas indicating gaps as small as a few micrometers. The gap extension at the interface was quantified and compared to the observation by confocal laser scanning microscope after trimming the specimen to the same cross-section. Also, video imaging of the composite during polymerization could provide information about real-time kinetics of contraction stress and resulting gaps, distinguishing them from those gaps resulting from poor adaptation of composite to the cavity prior to polymerization. Some samples were also subjected to a high resolution microfocus X-ray computed tomography (μCT) assessment; it was found that differentiation of smaller gaps from the radiolucent bonding layer was difficult with 3D μCT. Finally, a clinical imaging example using a newly developed dental SS-OCT system with an intra-oral scanning probe (Panasonic Healthcare, Japan) is presented. SS-OCT is a unique tool for clinical assessment and laboratory research on resin-based dental restorations. Supported by GCOE at TMDU and NCGG.

  12. A comparative study of noise in supercontinuum light sources for ultra-high resolution optical coherence tomography

    DEFF Research Database (Denmark)

    Maria J., Sanjuan-Ferrer,; Bravo Gonzalo, Ivan; Bondu, Magalie

    2017-01-01

    Supercontinuum (SC) light is a well-established technology, which finds applications in several domains ranging from chemistry to material science and imaging systems [1-2]. More specifically, its ultra-wide optical bandwidth and high average power make it an ideal tool for Optical Coherence...... Tomography (OCT). Over the last 5 years, numerous examples have demonstrated its high potential [3-4] in this context. However, SC light sources present pulse-to-pulse intensity variation that can limit the performance of any OCT system [5] by degrading their signal to noise ratio (SNR). To this goal, we...... have studied and compared the noise of several SC light sources and evaluated how their noise properties affect the performance of Ultra-High Resolution OCT (UHR-OCT) at 1300 nm. We have measured several SC light sources with different parameters (pulse length, energy, seed repetition rate, etc.). We...

  13. The B3-VLA CSS sample. VIII. New optical identifications from the Sloan Digital Sky Survey The ultraviolet-optical spectral energy distribution of the young radio sources

    Science.gov (United States)

    Fanti, C.; Fanti, R.; Zanichelli, A.; Dallacasa, D.; Stanghellini, C.

    2011-04-01

    Context. Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from the B3-VLA catalog: the B3-VLA CSS sample. Only ≈60% of the sources were optically identified. Aims: We aim to increase the number of optical identifications and study the properties of the host galaxies of young radio sources. Methods: We cross-correlated the CSS B3-VLA sample with the Sloan Digital Sky Survey (SDSS), DR7, and complemented the SDSS photometry with available GALEX (DR 4/5 and 6) and near-IR data from UKIRT and 2MASS. Results: We obtained new identifications and photometric redshifts for eight faint galaxies and for one quasar and two quasar candidates. Overall we have 27 galaxies with SDSS photometry in five bands, for which we derived the ultraviolet-optical spectral energy distribution (UV-O-SED). We extended our investigation to additional CSS/GPS selected from the literature. Most of the galaxies show an excess of ultra-violet (UV) radiation compared with the UV-O-SED of local radio-quiet ellipticals. We found a strong dependence of the UV excess on redshift and analyzed it assuming that it is generated either from the nucleus (hidden quasar) or from a young stellar population (YSP). We also compare the UV-O-SEDs of our CSS/GPS sources with those of a selection of large size (LSO) powerful radio sources from the literature. Conclusions: If the major process of the UV excess is caused by a YSP, our conclusion is that it is the result of the merger process that also triggered the onset of the radio source with some time delay. We do not see evidence for a major contribution from a YSP triggered by the radio sources itself. Appendices A-G are only available in electronic form at http://www.aanda.org

  14. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  15. The potential for optical beam shaping of UV laser sources for mass scale quarantine disinfection applications

    Science.gov (United States)

    Lizotte, Todd

    2010-08-01

    disinfection systems using high intensity UV laser sources instead of UV bulb techniques by using laser beam shaping optics in conjunction with traditional optical laser beam delivery techniques.

  16. Using the combination refraction-reflection solid to design omni-directional light source used in underwater wireless optical communication

    Science.gov (United States)

    Rao, Jionghui; Yao, Wenming; Wen, Linqiang

    2015-10-01

    Underwater wireless optical communication is a communication technology which uses laser as an information carrier and transmits data through water. Underwater wireless optical communication has some good features such as broader bandwidth, high transmission rate, better security, anti—interference performance. Therefore, it is promising to be widely used in the civil and military communication domains. It is also suitable for high-speed, short-range communication between underwater mobile vehicles. This paper presents a design approach of omni-directional light source used in underwater wireless optical communication, using TRACEPRO simulation tool to help design a combination solid composed of the lens, conical reflector and parabolic reflector, and using the modulated DPSS green laser in the transmitter module to output the laser beam in small divergence angles, after expanded by the combination refraction-reflection solid, the angle turns into a space divergence angle of 2π, achieving the omni-directional light source of hemisphere space, and test in the air and underwater, the result shows that the effect is fine. This paper analyzes the experimental test in the air and water, in order to make further improvement of the uniformity of light distribution, we optimize the reflector surface parameters of combination refraction-reflection solid and test in the air and water. The result shows that omni-directional light source used in underwater wireless optical communication optimized could achieve the uniformity of light distribution of underwater space divergence angle of 2π. Omni-directional light source used in underwater wireless optical communication designed in this paper has the characteristics of small size and uniformity of light distribution, it is suitable for application between UUVs, AUVs, Swimmer Delivery Vehicles (SDVs) and other underwater vehicle fleet, it realizes point-to-multipoint communications.

  17. Recent results and future plans for a 45 actuator adaptive x-ray optics experiment at the advanced light source

    Energy Technology Data Exchange (ETDEWEB)

    Brejnholt, Nicolai F., E-mail: brejnholt1@llnl.gov; Poyneer, Lisa A.; Hill, Randal M.; Pardini, Tommaso; Hagler, Lisle; Jackson, Jessie; Jeon, Jae; McCarville, Thomas J.; Palmer, David W. [Lawrence Livermore National Laboratory, Livermore, California (United States); Celestre, Richard [Advanced Light Source - Lawrence Berkeley National Laboratory, Berkeley, California (United States); Brooks, Audrey D. [Northrop Grumman - AOA Xinetics Inc., Cambridge, Massachusetts (United States)

    2016-07-27

    We report on the current status of the Adaptive X-ray Optics project run by Lawrence Livermore National Laboratory (LLNL). LLNL is collaborating with the Advanced Light Source (ALS) to demonstrate a near real-time adaptive X-ray optic. To this end, a custom-built 45 cm long deformable mirror has been installed at ALS beamline 5.3.1 (end station 2) for a two-year period that started in September 2014. We will outline general aspects of the instrument, present results from a recent experimental campaign and touch on future plans for the project.

  18. Compact akinetic swept source optical coherence tomography angiography at 1060 nm supporting a wide field of view and adaptive optics imaging modes of the posterior eye.

    Science.gov (United States)

    Salas, Matthias; Augustin, Marco; Felberer, Franz; Wartak, Andreas; Laslandes, Marie; Ginner, Laurin; Niederleithner, Michael; Ensher, Jason; Minneman, Michael P; Leitgeb, Rainer A; Drexler, Wolfgang; Levecq, Xavier; Schmidt-Erfurth, Ursula; Pircher, Michael

    2018-04-01

    Imaging of the human retina with high resolution is an essential step towards improved diagnosis and treatment control. In this paper, we introduce a compact, clinically user-friendly instrument based on swept source optical coherence tomography (SS-OCT). A key feature of the system is the realization of two different operation modes. The first operation mode is similar to conventional OCT imaging and provides large field of view (FoV) images (up to 45° × 30°) of the human retina and choroid with standard resolution. The second operation mode enables it to optically zoom into regions of interest with high transverse resolution using adaptive optics (AO). The FoV of this second operation mode (AO-OCT mode) is 3.0° × 2.8° and enables the visualization of individual retinal cells such as cone photoreceptors or choriocapillaris. The OCT engine is based on an akinetic swept source at 1060 nm and provides an A-scan rate of 200 kHz. Structural as well as angiographic information can be retrieved from the retina and choroid in both operational modes. The capabilities of the prototype are demonstrated in healthy and diseased eyes.

  19. Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xuepeng; 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); Yi, Longtao; Sun, Weiyuan; Li, Fangzuo; Jiang, Bowen [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); 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)

    2015-12-01

    Two combined optic systems based on polycapillary X-ray optics and single-bounce monocapillary optics (SBMO) were designed for focusing the X-rays from a conventional laboratory X-ray source. One was based on a polycapillary focusing X-ray lens (PFXRL) and a single-bounce ellipsoidal capillary (SBEC), in which the output focal spot with the size of tens of micrometers of the PFXRL was used as the “virtual” X-ray source for the SBEC. The other system was based on a polycapillary parallel X-ray lens (PPXRL) and a single-bounce parabolic capillary (SBPC), in which the PPXRL transformed the divergent X-ray beam from an X-ray source into a quasi-parallel X-ray beam with the divergence of sever milliradians as the incident illumination of the SBPC. The experiment results showed that the combined optic systems based on PFXRL and SBEC with a Mo rotating anode X-ray generator with the focal spot with a diameter of 300 μm could obtain a focal spot with the total gain of 14,300 and focal spot size of 37.4 μm, and the combined optic systems based on PPXRL and SBPC with the same X-ray source mentioned above could acquire a focal spot with the total gain of 580 and focal spot size of 58.3 μm, respectively. The two combined optic systems have potential applications in micro X-ray diffraction, micro X-ray fluorescence, micro X-ray absorption near edge structure, full field X-ray microscopes and so on.

  20. Three-Dimensional Cataract Crystalline Lens Imaging With Swept-Source Optical Coherence Tomography.

    Science.gov (United States)

    de Castro, Alberto; Benito, Antonio; Manzanera, Silvestre; Mompeán, Juan; Cañizares, Belén; Martínez, David; Marín, Jose María; Grulkowski, Ireneusz; Artal, Pablo

    2018-02-01

    To image, describe, and characterize different features visible in the crystalline lens of older adults with and without cataract when imaged three-dimensionally with a swept-source optical coherence tomography (SS-OCT) system. We used a new SS-OCT laboratory prototype designed to enhance the visualization of the crystalline lens and imaged the entire anterior segment of both eyes in two groups of participants: patients scheduled to undergo cataract surgery, n = 17, age range 36 to 91 years old, and volunteers without visual complains, n = 14, age range 20 to 81 years old. Pre-cataract surgery patients were also clinically graded according to the Lens Opacification Classification System III. The three-dimensional location and shape of the visible opacities were compared with the clinical grading. Hypo- and hyperreflective features were visible in the lens of all pre-cataract surgery patients and in some of the older adults in the volunteer group. When the clinical examination revealed cortical or subcapsular cataracts, hyperreflective features were visible either in the cortex parallel to the surfaces of the lens or in the posterior pole. Other type of opacities that appeared as hyporeflective localized features were identified in the cortex of the lens. The OCT signal in the nucleus of the crystalline lens correlated with the nuclear cataract clinical grade. A dedicated OCT is a useful tool to study in vivo the subtle opacities in the cataractous crystalline lens, revealing its position and size three-dimensionally. The use of these images allows obtaining more detailed information on the age-related changes leading to cataract.

  1. Optical system design of a speckle-free ultrafast Red-Green-Blue (RGB) source based on angularly multiplexed second harmonic generation from a TZDW source

    Science.gov (United States)

    Yao, Yuhong; Knox, Wayne H.

    2015-03-01

    We report the optical system design of a novel speckle-free ultrafast Red-Green-Blue (RGB) source based on angularly multiplexed simultaneous second harmonic generation from the efficiently generated Stokes and anti-Stokes pulses from a commercially available photonic crystal fiber (PCF) with two zero dispersion wavelengths (TZDW). We describe the optimized configuration of the TZDW fiber source which supports excitations of dual narrow-band pulses with peak wavelengths at 850 nm, 1260 nm and spectral bandwidths of 23 nm, 26 nm, respectively within 12 cm of commercially available TZDW PCF. The conversion efficiencies are as high as 44% and 33% from the pump source (a custom-built Yb:fiber master-oscillator-power-amplifier). As a result of the nonlinear dynamics of propagation, the dual pulses preserve their ultrashort pulse width (with measured autocorrelation traces of 200 fs and 227 fs,) which eliminates the need for dispersion compensation before harmonic generation. With proper optical design of the free-space harmonic generation system, we achieve milli-Watt power level red, green and blue pulses at 630 nm, 517 nm and 425 nm. Having much broader spectral bandwidths compared to picosecond RGB laser sources, the source is inherently speckle-free due to the ultra-short coherence length (99.4% excitation purities of the three primaries, leading to the coverage of 192% NTSC color gamut (CIE 1976). The reported RGB source features a very simple system geometry, its potential for power scaling is discussed with currently available technologies.

  2. Compact 6 dB Two-Color Continuous Variable Entangled Source Based on a Single Ring Optical Resonator

    Directory of Open Access Journals (Sweden)

    Ning Wang

    2018-02-01

    Full Text Available Continuous-variable entangled optical beams at the degenerate wavelength of 0.8 μm or 1.5 μm have been investigated extensively, but separately. The two-color entangled states of these two useful wavelengths, with sufficiently high degrees of entanglement, still lag behind. In this work, we analyze the various limiting factors that affect the entanglement degree. On the basis of this, we successfully achieve 6 dB of two-color quadrature entangled light beams by improving the escape efficiency of the nondegenerate optical amplifier, the stability of the phase-locking servo system, and the detection efficiency. Our entangled source is constructed only from a single ring optical resonator, and thus is highly compact, which is suitable for applications in long-distance quantum communication networks.

  3. The first neural probe integrated with light source (blue laser diode) for optical stimulation and electrical recording.

    Science.gov (United States)

    Park, HyungDal; Shin, Hyun-Joon; Cho, Il-Joo; Yoon, Eui-sung; Suh, Jun-Kyo Francis; Im, Maesoon; Yoon, Euisik; Kim, Yong-Jun; Kim, Jinseok

    2011-01-01

    In this paper, we report a neural probe which can selectively stimulate target neurons optically through Si wet etched mirror surface and record extracellular neural signals in iridium oxide tetrodes. Consequently, the proposed approach provides to improve directional problem and achieve at least 150/m gap distance between stimulation and recording sites by wet etched mirror surface in V-groove. Also, we developed light source, blue laser diode (OSRAM Blue Laser Diode_PL 450), integration through simple jig for one-touch butt-coupling. Furthermore, optical power and impedance of iridium oxide tetrodes were measured as 200 μW on 5 mW from LD and 206.5 k Ω at 1 kHz and we demonstrated insertion test of probe in 0.5% agarose-gel successfully. We have successfully transmitted a light of 450 nm to optical fiber through the integrated LD using by butt-coupling method.

  4. Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm

    OpenAIRE

    Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

    2014-01-01

    We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same ...

  5. Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source

    Directory of Open Access Journals (Sweden)

    Jordi Palacín

    2011-12-01

    Full Text Available In this paper, a low cost optical flow sensor is combined with an external laser device to measure surface displacements and mechanical oscillations. The measurement system is based on applying coherent light to a diffuser surface and using an optical flow sensor to analyze the reflected and transferred light to estimate the displacement of the surface or the laser spot. This work is focused on the characterization of this measurement system, which can have the optical flow sensor placed at different angles and distances from the diffuser surface. The results have shown that the displacement of the diffuser surface is badly estimated when the optical mouse sensor is placed in front of the diffuser surface (angular orientation >150° while the highest sensitivity is obtained when the sensor is located behind the diffuser surface and on the axis of the laser source (angular orientation 0°. In this case, the coefficient of determination of the measured displacement, R2, was very high (>0.99 with a relative error of less than 1.29%. Increasing the distance between the surface and the sensor also increased the sensitivity which increases linearly, R2 = 0.99. Finally, this measurement setup was proposed to measure very low frequency mechanical oscillations applied to the laser device, up to 0.01 Hz in this work. The results have shown that increasing the distance between the surface and the optical flow sensor also increases the sensitivity and the measurement range.

  6. OPTICAL PROPERTIES OF THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1 AND ITS STELLAR ENVIRONMENT

    International Nuclear Information System (INIS)

    Grise, F.; Kaaret, P.; Pakull, M. W.; Motch, C.

    2011-01-01

    Holmberg IX X-1 is an archetypal ultraluminous X-ray source (ULX). Here we study the properties of the optical counterpart and of its stellar environment using optical data from SUBARU/Faint Object Camera and Spectrograph, GEMINI/GMOS-N and Hubble Space Telescope (HST)/Advanced Camera for Surveys, as well as simultaneous Chandra X-ray data. The V ∼ 22.6 spectroscopically identified optical counterpart is part of a loose cluster with an age ∼ sun . The counterpart is more luminous than the other stars of the association, suggesting a non-negligible optical contribution from the accretion disk. An observed UV excess also points to non-stellar light similar to X-ray active low-mass X-ray binaries. A broad He II λ4686 emission line identified in the optical spectrum of the ULX further suggests optical light from X-ray reprocessing in the accretion disk. Using stellar evolutionary tracks, we have constrained the mass of the counterpart to be ∼> 10 M sun , even if the accretion disk contributes significantly to the optical luminosity. Comparison of the photometric properties of the counterpart with binary models show that the donor may be more massive, ∼> 25 M sun , with the ULX system likely undergoing case AB mass transfer. Finally, the counterpart exhibits photometric variability of 0.14 mag between two HST observations separated by 50 days which could be due to ellipsoidal variations and/or disk reprocessing of variable X-ray emission.

  7. Simultaneous topography and tomography of latent fingerprints using full-field swept-source optical coherence tomography

    Science.gov (United States)

    Dubey, Satish Kumar; Singh Mehta, Dalip; Anand, Arun; Shakher, Chandra

    2008-01-01

    We demonstrate simultaneous topography and tomography of latent fingerprints using full-field swept-source optical coherence tomography (OCT). The swept-source OCT system comprises a superluminescent diode (SLD) as broad-band light source, an acousto-optic tunable filter (AOTF) as frequency tuning device, and a compact, nearly common-path interferometer. Both the amplitude and the phase map of the interference fringe signal are reconstructed. Optical sectioning of the latent fingerprint sample is obtained by selective Fourier filtering and the topography is retrieved from the phase map. Interferometry, selective filtering, low coherence and hence better resolution are some of the advantages of the proposed system over the conventional fingerprint detection techniques. The present technique is non-invasive in nature and does not require any physical or chemical processing. Therefore, the quality of the sample does not alter and hence the same fingerprint can be used for other types of forensic test. Exploitation of low-coherence interferometry for fingerprint detection itself provides an edge over other existing techniques as fingerprints can even be lifted from low-reflecting surfaces. The proposed system is very economical and compact.

  8. Ultra-low noise supercontinuum source for ultra-high resolution optical coherence tomography at 1300 nm

    Science.gov (United States)

    Gonzalo, I. B.; Maria, M.; Engelsholm, R. D.; Feuchter, T.; Leick, L.; Moselund, P. M.; Podoleanu, A.; Bang, O.

    2018-02-01

    Supercontinuum (SC) sources are of great interest for many applications due to their ultra-broad optical bandwidth, good beam quality and high power spectral density [1]. In particular, the high average power over large bandwidths makes SC light sources excellent candidates for ultra-high resolution optical coherence tomography (UHR-OCT) [2-5]. However, conventional SC sources suffer from high pulse-to-pulse intensity fluctuations as a result of the noise-sensitive nonlinear effects involved in the SC generation process [6-9]. This intensity noise from the SC source can limit the performance of OCT, resulting in a reduced signal-to-noise ratio (SNR) [10-12]. Much work has been done to reduce the noise of the SC sources for instance with fiber tapers [7,8] or increasing the repetition rate of the pump laser for averaging in the spectrometer [10,12]. An alternative approach is to use all-normal dispersion (ANDi) fibers [13,14] to generate SC light from well-known coherent nonlinear processes [15-17]. In fact, reduction of SC noise using ANDi fibers compared to anomalous dispersion SC pumped by sub-picosecond pulses has been recently demonstrated [18], but a cladding mode was used to stabilize the ANDi SC. In this work, we characterize the noise performance of a femtosecond pumped ANDi based SC and a commercial SC source in an UHR-OCT system at 1300 nm. We show that the ANDi based SC presents exceptional noise properties compared to a commercial source. An improvement of 5 dB in SNR is measured in the UHR-OCT system, and the noise behavior resembles that of a superluminiscent diode. This preliminary study is a step forward towards development of an ultra-low noise SC source at 1300 nm for ultra-high resolution OCT.

  9. Soft X-ray sources and their optical counterparts in the error box of the COS-B source 2CG 135+01

    Energy Technology Data Exchange (ETDEWEB)

    Caraveo, P A; Bignami, G F [Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica Cosmica e Tecnologie Relative; Paul, J A [CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Section d' Astrophysique; Marano, B [Bologna Univ. (Italy). Ist. di Astronomia; Vettolani, G P [Consiglio Nazionale delle Ricerche, Bologna (Italy). Lab. di Radioastronomia

    1981-01-01

    We shall present here the Einstein observations for the 2CG 135+01 region where the results are complete in the sense that we have a satisfactory coverage of the COS-B error box and, more important, that all the IPC sources found have been identified, through both HRI and optical observations. In particular, the new spectral classifications of the present work were obtained at the Lojano Observatory (Bologna, Italy) with the Boller and Chivens spectrograph at the Cassegrain focus of the 1.52 in telescope. The spectral dispersion is 80 A/mm.

  10. Electro-optic spatial decoding on the spherical-wavefront Coulomb fields of plasma electron sources.

    Science.gov (United States)

    Huang, K; Esirkepov, T; Koga, J K; Kotaki, H; Mori, M; Hayashi, Y; Nakanii, N; Bulanov, S V; Kando, M

    2018-02-13

    Detections of the pulse durations and arrival timings of relativistic electron beams are important issues in accelerator physics. Electro-optic diagnostics on the Coulomb fields of electron beams have the advantages of single shot and non-destructive characteristics. We present a study of introducing the electro-optic spatial decoding technique to laser wakefield acceleration. By placing an electro-optic crystal very close to a gas target, we discovered that the Coulomb field of the electron beam possessed a spherical wavefront and was inconsistent with the previously widely used model. The field structure was demonstrated by experimental measurement, analytic calculations and simulations. A temporal mapping relationship with generality was derived in a geometry where the signals had spherical wavefronts. This study could be helpful for the applications of electro-optic diagnostics in laser plasma acceleration experiments.

  11. Development of refractive X-ray focusing optics at Diamond Light Source

    Science.gov (United States)

    Alianelli, L.; Sawhney, K. J. S.; Loader, I. M.; Jenkins, D. W. K.; Stevens, R.; Snigirev, A.; Snigireva, I.

    2007-09-01

    The Diamond Optics & Metrology Group and the collaborators at the STFC Central Microstructure Facility have initiated a program for the design and fabrication of in-line micro- and nano-focusing optics for synchrotron radiation beamlines. The first type of optics fabricated is a kinoform lens in silicon on the same model proposed by K. Evans- Lutterodt et al [Opt. Expr. 11 (2003) 919.]. The fabrication utilised ultra high resolution electron beam lithographic patterning of an electron sensitive SU8 polymer and deep reactive ion etching of silicon. The first test of the focusing properties was performed at the ESRF BM5 optics beamline. In this paper we present details on the design and fabrication, and discuss the test results.

  12. Integrated Quantum Optics: Experiments towards integrated quantum-light sources and quantum-enhanced sensing

    DEFF Research Database (Denmark)

    Hoff, Ulrich Busk

    The work presented in this thesis is focused on experimental application and generation of continuous variable quantum correlated states of light in integrated dielectric structures. Squeezed states are among the most exploited continuous variable optical states for free-space quantum-enhanced se...... is presented and an optimized device design is proposed. The devices have been fabricated and tested optically and preliminary interrogations of the output quantum noise have been performed....

  13. ULTRAHIGH SPEED SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF RETINAL AND CHORIOCAPILLARIS ALTERATIONS IN DIABETIC PATIENTS WITH AND WITHOUT RETINOPATHY.

    Science.gov (United States)

    Choi, WooJhon; Waheed, Nadia K; Moult, Eric M; Adhi, Mehreen; Lee, ByungKun; De Carlo, Talisa; Jayaraman, Vijaysekhar; Baumal, Caroline R; Duker, Jay S; Fujimoto, James G

    2017-01-01

    To investigate the utility of ultrahigh speed, swept source optical coherence tomography angiography in visualizing retinal microvascular and choriocapillaris (CC) changes in diabetic patients. The study was prospective and cross-sectional. A 1,050 nm wavelength, 400 kHz A-scan rate swept source optical coherence tomography prototype was used to perform volumetric optical coherence tomography angiography of the retinal and CC vasculatures in diabetic patients and normal subjects. Sixty-three eyes from 32 normal subjects, 9 eyes from 7 patients with proliferative diabetic retinopathy, 29 eyes from 16 patients with nonproliferative diabetic retinopathy, and 51 eyes from 28 diabetic patients without retinopathy were imaged. Retinal and CC microvascular abnormalities were observed in all stages of diabetic retinopathy. In nonproliferative diabetic retinopathy and proliferative diabetic retinopathy, optical coherence tomography angiography visualized a variety of vascular abnormalities, including clustered capillaries, dilated capillary segments, tortuous capillaries, regions of capillary dropout, reduced capillary density, abnormal capillary loops, and foveal avascular zone enlargement. In proliferative diabetic retinopathy, retinal neovascularization above the inner limiting membrane was visualized. Regions of CC flow impairment in patients with proliferative diabetic retinopathy and nonproliferative diabetic retinopathy were also observed. In 18 of the 51 of eyes from diabetic patients without retinopathy, retinal mircrovascular abnormalities were observed and CC flow impairment was found in 24 of the 51 diabetic eyes without retinopathy. The ability of optical coherence tomography angiography to visualize retinal and CC microvascular abnormalities suggests it may be a useful tool for understanding pathogenesis, evaluating treatment response, and earlier detection of vascular abnormalities in patients with diabetes.

  14. Optical Spectra of Candidate International Celestial Reference Frame (ICRF) Flat-spectrum Radio Sources. III

    Energy Technology Data Exchange (ETDEWEB)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia); Zenere, Katrina A., E-mail: oleg.titov@ga.gov.au [School of Physics, University of Sydney, NSW 2006 (Australia)

    2017-04-01

    In extending our spectroscopic program, which targets sources drawn from the International Celestial Reference Frame (ICRF) Catalog, we have obtained spectra for ∼160 compact, flat-spectrum radio sources and determined redshifts for 112 quasars and radio galaxies. A further 14 sources with featureless spectra have been classified as BL Lac objects. Spectra were obtained at three telescopes: the 3.58 m European Southern Observatory New Technology Telescope, and the two 8.2 m Gemini telescopes in Hawaii and Chile. While most of the sources are powerful quasars, a significant fraction of radio galaxies is also included from the list of non-defining ICRF radio sources.

  15. A Crowd-Sourcing Indoor Localization Algorithm via Optical Camera on a Smartphone Assisted by Wi-Fi Fingerprint RSSI.

    Science.gov (United States)

    Chen, Wei; Wang, Weiping; Li, Qun; Chang, Qiang; Hou, Hongtao

    2016-03-19

    Indoor positioning based on existing Wi-Fi fingerprints is becoming more and more common. Unfortunately, the Wi-Fi fingerprint is susceptible to multiple path interferences, signal attenuation, and environmental changes, which leads to low accuracy. Meanwhile, with the recent advances in charge-coupled device (CCD) technologies and the processing speed of smartphones, indoor positioning using the optical camera on a smartphone has become an attractive research topic; however, the major challenge is its high computational complexity; as a result, real-time positioning cannot be achieved. In this paper we introduce a crowd-sourcing indoor localization algorithm via an optical camera and orientation sensor on a smartphone to address these issues. First, we use Wi-Fi fingerprint based on the K Weighted Nearest Neighbor (KWNN) algorithm to make a coarse estimation. Second, we adopt a mean-weighted exponent algorithm to fuse optical image features and orientation sensor data as well as KWNN in the smartphone to refine the result. Furthermore, a crowd-sourcing approach is utilized to update and supplement the positioning database. We perform several experiments comparing our approach with other positioning algorithms on a common smartphone to evaluate the performance of the proposed sensor-calibrated algorithm, and the results demonstrate that the proposed algorithm could significantly improve accuracy, stability, and applicability of positioning.

  16. An intelligent despeckling method for swept source optical coherence tomography images of skin

    Science.gov (United States)

    Adabi, Saba; Mohebbikarkhoran, Hamed; Mehregan, Darius; Conforto, Silvia; Nasiriavanaki, Mohammadreza

    2017-03-01

    Optical Coherence Optical coherence tomography is a powerful high-resolution imaging method with a broad biomedical application. Nonetheless, OCT images suffer from a multiplicative artefacts so-called speckle, a result of coherent imaging of system. Digital filters become ubiquitous means for speckle reduction. Addressing the fact that there still a room for despeckling in OCT, we proposed an intelligent speckle reduction framework based on OCT tissue morphological, textural and optical features that through a trained network selects the winner filter in which adaptively suppress the speckle noise while preserve structural information of OCT signal. These parameters are calculated for different steps of the procedure to be used in designed Artificial Neural Network decider that select the best denoising technique for each segment of the image. Results of training shows the dominant filter is BM3D from the last category.

  17. Concentrator optical characterization using computer mathematical modelling and point source testing

    Science.gov (United States)

    Dennison, E. W.; John, S. L.; Trentelman, G. F.

    1984-01-01

    The optical characteristics of a paraboloidal solar concentrator are analyzed using the intercept factor curve (a format for image data) to describe the results of a mathematical model and to represent reduced data from experimental testing. This procedure makes it possible not only to test an assembled concentrator, but also to evaluate single optical panels or to conduct non-solar tests of an assembled concentrator. The use of three-dimensional ray tracing computer programs to calculate the mathematical model is described. These ray tracing programs can include any type of optical configuration from simple paraboloids to array of spherical facets and can be adapted to microcomputers or larger computers, which can graphically display real-time comparison of calculated and measured data.

  18. Transfer standard for the spectral density of relative intensity noise of optical fiber sources near 1550 nm

    International Nuclear Information System (INIS)

    Obarski, Gregory E.; Splett, Jolene D.

    2001-01-01

    We have developed a transfer standard for the spectral density of relative intensity noise (RIN) of optical fiber sources near 1550 nm. Amplified spontaneous emission (ASE) from an erbium-doped fiber amplifier (EDFA), when it is optically filtered over a narrow band (<5 nm), yields a stable RIN spectrum that is practically constant to several tens of gigahertz. The RIN is calculated from the power spectral density as measured with a calibrated optical spectrum analyzer. For a typical device it is -110 dB/Hz, with uncertainty ≤0.12 dB/Hz. The invariance of the RIN under attenuation yields a considerable dynamic range with respect to rf noise levels. Results are compared with those from a second method that uses a distributed-feedback laser (DFB) that has a Poisson-limited RIN. Application of each method to the same RIN measurement system yields frequency-dependent calibration functions that, when they are averaged, differ by ≤0.2 dB. [copyright] 2001 Optical Society of America

  19. Transfer standard for the spectral density of relative intensity noise of optical fiber sources near 1550 nm

    Energy Technology Data Exchange (ETDEWEB)

    Obarski, Gregory E.; Splett, Jolene D.

    2001-06-01

    We have developed a transfer standard for the spectral density of relative intensity noise (RIN) of optical fiber sources near 1550 nm. Amplified spontaneous emission (ASE) from an erbium-doped fiber amplifier (EDFA), when it is optically filtered over a narrow band ({lt}5 nm), yields a stable RIN spectrum that is practically constant to several tens of gigahertz. The RIN is calculated from the power spectral density as measured with a calibrated optical spectrum analyzer. For a typical device it is {minus}110 dB/Hz, with uncertainty {le}0.12 dB/Hz. The invariance of the RIN under attenuation yields a considerable dynamic range with respect to rf noise levels. Results are compared with those from a second method that uses a distributed-feedback laser (DFB) that has a Poisson-limited RIN. Application of each method to the same RIN measurement system yields frequency-dependent calibration functions that, when they are averaged, differ by {le}0.2 dB. {copyright} 2001 Optical Society of America

  20. Quantitative study of luminescence optical tomography. Application to sources localisation in molecular imaging

    International Nuclear Information System (INIS)

    Boffety, Matthieu

    2010-01-01

    Molecular imaging is a major modality in the field of preclinical research. Among the existing methods, techniques based on optical detection of visible or near infrared radiation are the most recent and are mainly represented by luminescence optical tomography techniques. These methods allow for 3D characterization of a biological medium by reconstructing maps of concentration or localisation of luminescent beacons sensitive to biological and chemical processes at the molecular or cellular scale. Luminescence optical tomography is based on a model of light propagation in tissues, a protocol for acquiring surface signal and a numerical inversion procedure used to reconstruct the parameters of interest. This thesis is structured around these three axes and provides an answer to each problem. The main objective of this study is to introduce and present the tools to evaluate the theoretical performances of optical tomography methods. One of its major outcomes is the realisation of experimental tomographic reconstructions from images acquired by an optical imager designed for 2D planar imaging and developed by the company Quidd. In a first step we develop the theory of transport in scattering medium to establish the concept on which our work will rely. We present two different propagation models as well as resolution methods and theoretical difficulties associated with them. In a second part we introduce the statistical tools used to characterise tomographic systems. We define and apply a procedure to simple situations in luminescence optical tomography. The last part of this work presents the development of an inversion procedure. After introducing the theoretical framework we validate the procedure from numerical data before successfully applying it to experimental measurements. (author) [fr

  1. Electro-optic sampling of THz pulses at the CTR source at FLASH

    International Nuclear Information System (INIS)

    Wunderlich, Steffen

    2012-06-01

    Several applications in material science, non-linear optics and solid-state physics require short pulses with a high pulse energy of radiation in the far-infrared and in the terahertz (THz) regime in particular. As described in the following, coherent transition radiation generated by high-relativistic electron bunches at FLASH provides broadband single-cycle pulses of sub-picosecond length. The pulses are characterized using the quantitative and time-resolved technique of electro-optic sampling showing peak field strengths in the order of 1 MV/cm.

  2. Electro-optic sampling of THz pulses at the CTR source at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Steffen

    2012-06-15

    Several applications in material science, non-linear optics and solid-state physics require short pulses with a high pulse energy of radiation in the far-infrared and in the terahertz (THz) regime in particular. As described in the following, coherent transition radiation generated by high-relativistic electron bunches at FLASH provides broadband single-cycle pulses of sub-picosecond length. The pulses are characterized using the quantitative and time-resolved technique of electro-optic sampling showing peak field strengths in the order of 1 MV/cm.

  3. Multimodal optical coherence tomography and fluorescence lifetime imaging with interleaved excitation sources for simultaneous endogenous and exogenous fluorescence.

    Science.gov (United States)

    Shrestha, Sebina; Serafino, Michael J; Rico-Jimenez, Jesus; Park, Jesung; Chen, Xi; Zhaorigetu, Siqin; Walton, Brian L; Jo, Javier A; Applegate, Brian E

    2016-09-01

    Multimodal imaging probes a variety of tissue properties in a single image acquisition by merging complimentary imaging technologies. Exploiting synergies amongst the data, algorithms can be developed that lead to better tissue characterization than could be accomplished by the constituent imaging modalities taken alone. The combination of optical coherence tomography (OCT) with fluorescence lifetime imaging microscopy (FLIM) provides access to detailed tissue morphology and local biochemistry. The optical system described here merges 1310 nm swept-source OCT with time-domain FLIM having excitation at 355 and 532 nm. The pulses from 355 and 532 nm lasers have been interleaved to enable simultaneous acquisition of endogenous and exogenous fluorescence signals, respectively. The multimodal imaging system was validated using tissue phantoms. Nonspecific tagging with Alexa Flour 532 in a Watanbe rabbit aorta and active tagging of the LOX-1 receptor in human coronary artery, demonstrate the capacity of the system for simultaneous acquisition of OCT, endogenous FLIM, and exogenous FLIM in tissues.

  4. Increasing signal-to-noise ratio of swept-source optical coherence tomography by oversampling in k-space

    Science.gov (United States)

    Nagib, Karim; Mezgebo, Biniyam; Thakur, Rahul; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-03-01

    Optical coherence tomography systems suffer from noise that could reduce ability to interpret reconstructed images correctly. We describe a method to increase the signal-to-noise ratio of swept-source optical coherence tomography (SSOCT) using oversampling in k-space. Due to this oversampling, information redundancy would be introduced in the measured interferogram that could be used to reduce white noise in the reconstructed A-scan. We applied our novel scaled nonuniform discrete Fourier transform to oversampled SS-OCT interferograms to reconstruct images of a salamander egg. The peak-signal-to-noise (PSNR) between the reconstructed images using interferograms sampled at 250MS/s andz50MS/s demonstrate that this oversampling increased the signal-to-noise ratio by 25.22 dB.

  5. Silica Optical Fibers Doped with Nanoparticles for Fiber Lasers and Broadband Sources

    Czech Academy of Sciences Publication Activity Database

    Kašík, Ivan; Peterka, Pavel; Mrázek, Jan; Honzátko, Pavel

    2016-01-01

    Roč. 12, č. 3 (2016), s. 277-290 ISSN 1573-4137 R&D Projects: GA ČR GP13-37368P; GA ČR GA14-35256S Institutional support: RVO:67985882 Keywords : Fiber laser * Ceramics * Nanocrystal Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.062, year: 2016

  6. Frequency-swept Light Sources for Optical Coherence Tomography in the 1060nm range

    DEFF Research Database (Denmark)

    Marschall, Sebastian

    Optical coherence tomography (OCT) is a non-invasive imaging technique for visualizing the internal structure of scattering materials, such as biological tissues. It generates two- or three-dimensional images of the sample with cellular (micrometer) resolution. OCT has become an important instrum...

  7. Short-period AM CVn systems as optical, X-ray and gravitational-wave sources

    NARCIS (Netherlands)

    Nelemans, G.; Yungelson, L.; Portegies Zwart, S.F.

    2004-01-01

    We model the population of AM CVn systems in the Galaxy and discuss the detectability of these systems with optical, X-ray and gravitational-wave detectors. We concentrate on the short-period (P < 1500 s) systems, some of which are expected to be in a phase of direct-impact accretion. Using a

  8. Retrieval of Aerosol Optical Depth Over Land by Inverse Modeling of Multi-Source Satellite Data

    NARCIS (Netherlands)

    Wu, Y.

    2018-01-01

    The Aerosol Optical Depth (AOD), a measure of the scattering and absorption of light by aerosols, has been extensively used for scientific research such as monitoring air quality near the surface due to fine particles aggregated, aerosol radiative forcing (cooling effect against the warming effect

  9. Two-step design method for highly compact three-dimensional freeform optical system for LED surface light source.

    Science.gov (United States)

    Mao, Xianglong; Li, Hongtao; Han, Yanjun; Luo, Yi

    2014-10-20

    Designing an illumination system for a surface light source with a strict compactness requirement is quite challenging, especially for the general three-dimensional (3D) case. In accordance with the two key features of an expected illumination distribution, i.e., a well-controlled boundary and a precise illumination pattern, a two-step design method is proposed in this paper for highly compact 3D freeform illumination systems. In the first step, a target shape scaling strategy is combined with an iterative feedback modification algorithm to generate an optimized freeform optical system with a well-controlled boundary of the target distribution. In the second step, a set of selected radii of the system obtained in the first step are optimized to further improve the illuminating quality within the target region. The method is quite flexible and effective to design highly compact optical systems with almost no restriction on the shape of the desired target field. As examples, three highly compact freeform lenses with ratio of center height h of the lens and the maximum dimension D of the source ≤ 2.5:1 are designed for LED surface light sources to form a uniform illumination distribution on a rectangular, a cross-shaped and a complex cross pierced target plane respectively. High light control efficiency of η > 0.7 as well as low relative standard illumination deviation of RSD < 0.07 is obtained simultaneously for all the three design examples.

  10. Phase-sensitive optical coherence tomography-based vibrometry using a highly phase-stable akinetic swept laser source

    Energy Technology Data Exchange (ETDEWEB)

    Applegate, Brian E.; Park, Jesung; Carbajal, Esteban [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States); Oghalai, John S. [Department of Otolaryngology - Head and Neck Surgery, Stanford University, Stanford, California (United States)

    2015-12-31

    Phase-sensitive Optical Coherence Tomography (PhOCT) is an emerging tool for in vivo investigation of the vibratory function of the intact middle and inner ear. PhOCT is able to resolve micron scale tissue morphology in three dimensions as well as measure picometer scale motion at each spatial position. Most PhOCT systems to date have relied upon the phase stability offered by spectrometer detection. On the other hand swept laser source based PhOCT offers a number of advantages including balanced detection, long imaging depths, and high imaging speeds. Unfortunately the inherent phase instability of traditional swept laser sources has necessitated complex user developed hardware/software solutions to restore phase sensitivity. Here we present recent results using a prototype swept laser that overcomes these issues. The akinetic swept laser is electronically tuned and precisely controls sweeps without any mechanical movement, which results in high phase stability. We have developed an optical fiber based PhOCT system around the akinetic laser source that had a 1550 nm center wavelength and a sweep rate of 140 kHz. The stability of the system was measured to be 4.4 pm with a calibrated reflector, thus demonstrating near shot noise limited performance. Using this PhOCT system, we have acquired structural and vibratory measurements of the middle ear in a mouse model, post mortem. The quality of the results suggest that the akinetic laser source is a superior laser source for PhOCT with many advantages that greatly reduces the required complexity of the imaging system.

  11. Sources

    International Nuclear Information System (INIS)

    Duffy, L.P.

    1991-01-01

    This paper discusses the sources of radiation in the narrow perspective of radioactivity and the even narrow perspective of those sources that concern environmental management and restoration activities at DOE facilities, as well as a few related sources. Sources of irritation, Sources of inflammatory jingoism, and Sources of information. First, the sources of irritation fall into three categories: No reliable scientific ombudsman to speak without bias and prejudice for the public good, Technical jargon with unclear definitions exists within the radioactive nomenclature, and Scientific community keeps a low-profile with regard to public information. The next area of personal concern are the sources of inflammation. This include such things as: Plutonium being described as the most dangerous substance known to man, The amount of plutonium required to make a bomb, Talk of transuranic waste containing plutonium and its health affects, TMI-2 and Chernobyl being described as Siamese twins, Inadequate information on low-level disposal sites and current regulatory requirements under 10 CFR 61, Enhanced engineered waste disposal not being presented to the public accurately. Numerous sources of disinformation regarding low level radiation high-level radiation, Elusive nature of the scientific community, The Federal and State Health Agencies resources to address comparative risk, and Regulatory agencies speaking out without the support of the scientific community

  12. Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic

    Directory of Open Access Journals (Sweden)

    R. A. de Villiers

    2010-06-01

    Full Text Available Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm including volume depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions. Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient 532 nm,volume depolarization and color ratio between 1064 and 532 nm in aerosol layers along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Optical depth of the aerosol layers are always rather small (<4% while transported over the Arctic and ratio of the total attenuated backscatter (i.e. including molecular contribution provide more stable result than conventional aerosol backscatter ratio. Above Asia, CALIPSO data indicate more depolarization (up to 15% and largest color ratio (>0.5 for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust, while low depolarization together with smaller and quasi constant color ratio (≈0.3 are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarization ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European

  13. Possibilities for direct optical observation of negative hydrogen ions in ion beam plasma sources via Rayleigh or Thomson scattering

    International Nuclear Information System (INIS)

    Burgess, D.D.

    1985-01-01

    The possibilities of applying optical scattering techniques to the determination of H - concentrations in plasma sources relevant to negative ion beam generation are considered. Rayleigh scattering measurements for incident wavelengths just below the H - photoionization limit appear to be only just feasible experimentally. A more promising possibility is observation of the modification in a plasma containing negative ions of the collective ion-feature in Thomson scattering. Numerical predictions of the effects of H - concentration on the spectral distribution of the ion-feature are presented. (author)

  14. Optical spectrum of the HDE 245770 and X-ray flares of the transient sources A 0535+26

    International Nuclear Information System (INIS)

    Aab, O.Eh.

    1985-01-01

    Investigation results are presented for the optical component of the transient X-ray source A 0535+26, the Be star HDE 245770. The investigation is based on the spectrograms with dispersions 9, 14 and 28 A/mm obtained during three years with the 6-meter telescope. A list of lines and their parameters within the range lambdalambda 3450-7000 A is given. Variability of the spectrum for the three years and a violent change in the spectrum in January 1981 are noted

  15. Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

    Science.gov (United States)

    Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

    2013-11-01

    To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  16. An open source digital servo for atomic, molecular, and optical physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Leibrandt, D. R., E-mail: david.leibrandt@nist.gov; Heidecker, J. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2015-12-15

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of {sup 27}Al{sup +} in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  17. Iterative procedure for in-situ EUV optical testing with an incoherent source

    Energy Technology Data Exchange (ETDEWEB)

    Miyawaka, Ryan; Naulleau, Patrick; Zakhor, Avideh

    2009-12-01

    We propose an iterative method for in-situ optical testing under partially coherent illumination that relies on the rapid computation of aerial images. In this method a known pattern is imaged with the test optic at several planes through focus. A model is created that iterates through possible aberration maps until the through-focus series of aerial images matches the experimental result. The computation time of calculating the through-focus series is significantly reduced by a-SOCS, an adapted form of the Sum Of Coherent Systems (SOCS) decomposition. In this method, the Hopkins formulation is described by an operator S which maps the space of pupil aberrations to the space of aerial images. This operator is well approximated by a truncated sum of its spectral components.

  18. An open source digital servo for atomic, molecular, and optical physics experiments

    Science.gov (United States)

    Leibrandt, D. R.; Heidecker, J.

    2015-12-01

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of 27Al+ in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  19. An open source digital servo for atomic, molecular, and optical physics experiments

    International Nuclear Information System (INIS)

    Leibrandt, D. R.; Heidecker, J.

    2015-01-01

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of 27 Al + in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser

  20. DeVelopment of the high-intensity polarized H- source with proton charge exchange on sodium optically oriented atoms

    International Nuclear Information System (INIS)

    Zelenskij, A.N.; Kokhanovskij, S.A.

    1982-01-01

    The results of experimental study on the source of polarized H - ions at polarized electron capture by proton from optically oriented sodium atoms are presented. Circular-polarized dye laser radiation with lamp pumping is used for polarization of highly dense sodium vapors in the pulsed mode. A facility for polarization measurement in the ion source is described. Dependence of the counting rate of metastables for the right and left circular radiation polarization in respect to wave length is presented. The results of measuring the degree of polarization under change of sodium density are revealed. The measurements have disclosed that obtaining of high polarization degree at 20-30% charge exchange effectiveness is possible but large radiation power is required. Use of a dense charge exchange target provides high effectiveness of hte whole polarization process. Yield of polarized H - ions can approach 10 μA/1 mA of the initial proton current

  1. Management of radiation sources and personal dosimeters based on the optical identification using two-dimensional barcode

    International Nuclear Information System (INIS)

    Takao, Hideaki; Yoshida, Masahiro; Kaneko, Mamoru; Miura, Miwa; Hayashida, Rika; Okumura, Yutaka; Matsuda, Naoki

    2006-01-01

    For accurate and efficient radiation safety management in facilities using radioisotopes, two-dimensional barcode (2-DC) was applied to the optical identification of radiation sources and personal dosimeters. The mobile personal computer (PC) equipped with a barcode reader, which has imported inventory records from the pre-existing radiation management system, enabled us to finish inventory procedures for 170 2-DC-labelled radiation sources in as short as 20min by one person. Identification of 270 personal dosimeters in their monthly replacement procedures also successfully completed within 20 min by incorporating pre-labeled 2-DC to PC installed with inventory records of dosimeters and radiation workers. As equipments and software required for 2-DC are affordable, easy to operate, and potentially expandable, the introduction of 2-DC system may help to establish practically higher level of radiation management. (author)

  2. Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system.

    Science.gov (United States)

    Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

    2007-02-01

    We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

  3. Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system

    Science.gov (United States)

    Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

    2007-02-01

    We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

  4. Correlation Wave-Front Sensing Algorithms for Shack-Hartmann-Based Adaptive Optics using a Point Source

    International Nuclear Information System (INIS)

    Poynee, L A

    2003-01-01

    Shack-Hartmann based Adaptive Optics system with a point-source reference normally use a wave-front sensing algorithm that estimates the centroid (center of mass) of the point-source image 'spot' to determine the wave-front slope. The centroiding algorithm suffers for several weaknesses. For a small number of pixels, the algorithm gain is dependent on spot size. The use of many pixels on the detector leads to significant propagation of read noise. Finally, background light or spot halo aberrations can skew results. In this paper an alternative algorithm that suffers from none of these problems is proposed: correlation of the spot with a ideal reference spot. The correlation method is derived and a theoretical analysis evaluates its performance in comparison with centroiding. Both simulation and data from real AO systems are used to illustrate the results. The correlation algorithm is more robust than centroiding, but requires more computation

  5. The optical properties of a double focusing bending magnet measured with a thin alpha source

    International Nuclear Information System (INIS)

    Armitage, S.A.; Eastham, D.A.

    1978-01-01

    The focusing properties of the 90 0 inflector magnet for the Nuclear Structure Facility (NSF) tandem at Daresbury Laboratory have been measured in the 2rho configuration using very thin alpha sources and a position-sensitive detector. (Auth.)

  6. Experimental demonstration of novel source-free ONUs in bidirectional RF up-converted optical OFDM-PON utilizing polarization multiplexing.

    Science.gov (United States)

    Zhang, Chongfu; Chen, Chen; Feng, Yuan; Qiu, Kun

    2012-03-12

    We propose and experimentally demonstrate a novel cost-effective optical orthogonal frequency-division multiplexing-based passive optical network (OFDM-PON) system, wherein all optical network units (ONUs) are source-free not only in the optical domain but also in the electric domain, by utilizing polarization multiplexing (PolMUX) in the downlink transmission. Two pure optical bands with a frequency interval of 10 GHz and downlink up-converted 10 GHz OFDM signal are carried in two orthogonal states of polarization (SOPs), respectively. 10 GHz radio frequency (RF) source can be generated by a heterodyne of two pure optical bands after polarization beam splitting in each ONU, therefore it can be used to down-convert the downlink OFDM signal and up-convert the uplink OFDM signal. In the whole bidirectional up-converted OFDM-PON system, only one single RF source is employed in the optical line terminal (OLT). Experimental results successfully verify the feasibility of our proposed cost-effective optical OFDM-PON system.

  7. Ultra-compact swept-source optical coherence tomography handheld probe with motorized focus adjustment (Conference Presentation)

    Science.gov (United States)

    LaRocca, Francesco; Nankivil, Derek; Keller, Brenton; Farsiu, Sina; Izatt, Joseph A.

    2017-02-01

    Handheld optical coherence tomography (OCT) systems facilitate imaging of young children, bedridden subjects, and those with less stable fixation. Smaller and lighter OCT probes allow for more efficient imaging and reduced operator fatigue, which is critical for prolonged use in either the operating room or neonatal intensive care unit. In addition to size and weight, the imaging speed, image quality, field of view, resolution, and focus correction capability are critical parameters that determine the clinical utility of a handheld probe. Here, we describe an ultra-compact swept source (SS) OCT handheld probe weighing only 211 g (half the weight of the next lightest handheld SSOCT probe in the literature) with 20.1 µm lateral resolution, 7 µm axial resolution, 102 dB peak sensitivity, a 27° x 23° field of view, and motorized focus adjustment for refraction correction between -10 to +16 D. A 2D microelectromechanical systems (MEMS) scanner, a converging beam-at-scanner telescope configuration, and an optical design employing 6 different custom optics were used to minimize device size and weight while achieving diffraction limited performance throughout the system's field of view. Custom graphics processing unit (GPU)-accelerated software was used to provide real-time display of OCT B-scans and volumes. Retinal images were acquired from adult volunteers to demonstrate imaging performance.

  8. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  9. Optical properties and source analysis of aerosols over a desert area in Dunhuang, Northwest china

    Science.gov (United States)

    Ma, Yongjing; Xin, Jinyuan; Ma, Yining; Kong, Lingbin; Zhang, Kequan; Zhang, Wenyu; Wang, Yuesi; Wang, Xiuqin; Zhu, Yongfeng

    2017-08-01

    Aerosol observational data for 2012 obtained from Dunhuang Station of CARE-China (Campaign on Atmospheric Aerosol Research Network of China) were analyzed to achieve in-depth knowledge of aerosol optical properties over Dunhuang region. The results showed that the annual average aerosol optical depth (AOD) at 500 nm was 0.32±0.06, and the Ångström exponent ( α) was 0.73 ± 0.27. Aerosol optical properties revealed significant seasonal characteristics. Frequent sandstorms in MAM (March-April-May) resulted in the seasonal maximum AOD, 0.41 ± 0.04, and a relatively smaller α value, 0.44±0.04. The tourism seasons, JJA (June-July-August) and SON (September-October-November) coincide with serious emissions of small anthropogenic aerosols. While in DJF (December-January-February), the composition of the atmosphere was a mixture of dust particles and polluted aerosols released by domestic heating; the average AOD and α were 0.29 ± 0.02 and 0.66 ± 0.17, respectively. Different air masses exhibited different degrees of influence on the aerosol concentration over Dunhuang in different seasons. During MAM, ranges of AOD (0.11-1.18) and α (0.06-0.82) were the largest under the dust influence of northwest-short-distance air mass in the four trajectories. Urban aerosols transported by northwest-short-distance air mass accounted for a very large proportion in JJA and the mixed aerosols observed in SON were mainly conveyed by air masses from the west. In DJF, the similar ranges of AOD and α under the three air mass demonstrated the analogous diffusion effects on regional pollutants over Dunhuang.

  10. An atomic beam source for fast loading of a magneto-optical trap under high vacuum

    DEFF Research Database (Denmark)

    McDowall, P.D.; Hilliard, Andrew; Grünzweig, T.

    2012-01-01

    We report on a directional atomic beam created using an alkali metal dispenser and a nozzle. By applying a high current (15 A) pulse to the dispenser at room temperature we can rapidly heat it to a temperature at which it starts dispensing, avoiding the need for preheating. The atomic beam produced...... is capable of loading 90 of a magneto-optical trap (MOT) in less than 7 s while maintaining a low vacuum pressure of 10 -11 Torr. The transverse velocity components of the atomic beam are measured to be within typical capture velocities of a rubidium MOT. Finally, we show that the atomic beam can be turned...

  11. Noninvasive Characterisation of Foot Reflexology Areas by Swept Source-Optical Coherence Tomography in Patients with Low Back Pain

    Directory of Open Access Journals (Sweden)

    Krishna Dalal

    2013-01-01

    Full Text Available Objective. When exploring the scientific basis of reflexology techniques, elucidation of the surface and subsurface features of reflexology areas (RAs is crucial. In this study, the subcutaneous features of RAs related to the lumbar vertebrae were evaluated by swept source-optical coherence tomography (SS-OCT in subjects with and without low back pain (LBP. Methods. Volunteers without LBP (n=6 (male : female = 1 : 1 and subjects with LBP (n=15 (male : female = 2 : 3 were clinically examined in terms of skin colour (visual perception, localised tenderness (visual analogue scale and structural as well as optical attributes as per SS-OCT. From each subject, 6 optical tomograms were recorded from equidistant transverse planes along the longitudinal axis of the RAs, and from each tomogram, 25 different spatial locations were considered for recording SS-OCT image attributes. The images were analysed with respect to the optical intensity distributions and thicknesses of different skin layers by using AxioVision Rel. 4.8.2 software. The SS-OCT images could be categorised into 4 pathological grades (i.e., 0, 1, 2, and 3 according to distinctness in the visible skin layers. Results. Three specific grades for abnormalities in SS-OCT images were identified considering gradual loss of distinctness and increase in luminosity of skin layers. Almost 90.05% subjects were of mixed type having predominance in certain grades. Conclusion. The skin SS-OCT system demonstrated a definite association of the surface features of healthy/unhealthy RAs with cutaneous features and the clinical status of the lumbar vertebrae.

  12. Noninvasive characterisation of foot reflexology areas by swept source-optical coherence tomography in patients with low back pain.

    Science.gov (United States)

    Dalal, Krishna; Elanchezhiyan, D; Das, Raunak; Dalal, Devjyoti; Pandey, Ravindra Mohan; Chatterjee, Subhamoy; Upadhyay, Ashish Datt; Maran, V Bharathi; Chatterjee, Jyotirmoy

    2013-01-01

    Objective. When exploring the scientific basis of reflexology techniques, elucidation of the surface and subsurface features of reflexology areas (RAs) is crucial. In this study, the subcutaneous features of RAs related to the lumbar vertebrae were evaluated by swept source-optical coherence tomography (SS-OCT) in subjects with and without low back pain (LBP). Methods. Volunteers without LBP (n = 6 (male : female = 1 : 1)) and subjects with LBP (n = 15 (male : female = 2 : 3)) were clinically examined in terms of skin colour (visual perception), localised tenderness (visual analogue scale) and structural as well as optical attributes as per SS-OCT. From each subject, 6 optical tomograms were recorded from equidistant transverse planes along the longitudinal axis of the RAs, and from each tomogram, 25 different spatial locations were considered for recording SS-OCT image attributes. The images were analysed with respect to the optical intensity distributions and thicknesses of different skin layers by using AxioVision Rel. 4.8.2 software. The SS-OCT images could be categorised into 4 pathological grades (i.e., 0, 1, 2, and 3) according to distinctness in the visible skin layers. Results. Three specific grades for abnormalities in SS-OCT images were identified considering gradual loss of distinctness and increase in luminosity of skin layers. Almost 90.05% subjects were of mixed type having predominance in certain grades. Conclusion. The skin SS-OCT system demonstrated a definite association of the surface features of healthy/unhealthy RAs with cutaneous features and the clinical status of the lumbar vertebrae.

  13. Impact of aerosol particle sources on optical properties in urban, regional and remote areas in the north-western Mediterranean

    Science.gov (United States)

    Ealo, Marina; Alastuey, Andrés; Pérez, Noemí; Ripoll, Anna; Querol, Xavier; Pandolfi, Marco

    2018-01-01

    sp and σap, being the second most efficient light-absorbing source in BCN (MAE = 0.9 m2 g-1). The traffic source at BCN and the industrial/traffic at MSY exhibited the highest MAEs (1.7 and 0.9 m2 g-1). These sources were major contributors to σap at BCN and MSY; however at MSA, secondary nitrate exerted the highest influence on σap (MAE = 0.4 m2 g-1). The sources which were predominantly composed of fine and relatively dark particles, such as industrial/traffic, aged organics and V-Ni, were simultaneously characterized by low single scattering albedo (SSA) and a high scattering Ångström exponent (SAE). Conversely, mineral and aged marine showed the lowest SAE and the highest SSA, being scattering the dominant process in the light extinction. The good agreement found between modelled and measured particle optical properties allowed the reconstruction of σsp and σap long-term series over the period 2004-2014 at MSY. Significant decreasing trends were found for the modelled σsp and σap (-4.6 and -4.1 % yr-1).

  14. The advantages of a swept source optical coherence tomography system in the evaluation of occlusal disorders

    Science.gov (United States)

    Marcauteanu, Corina; Bradu, Adrian; Sinescu, Cosmin; Topala, Florin Ionel; Negrutiu, Meda Lavinia; Duma, Virgil Florin; Podoleanu, Adrian Gh.

    2014-01-01

    Occlusal disorders are characterized by multiple dental and periodontal signs. Some of these are reversible (such as excessive tooth mobility, fremitus, tooth pain, migration of teeth in the absence of periodontitis), some are not (pathological occlusal/incisal wear, abfractions, enamel cracks, tooth fractures, gingival recessions). In this paper we prove the advantages of a fast swept source OCT system in the diagnosis of pathological incisal wear, a key sign of the occlusal disorders. On 15 extracted frontal teeth four levels of pathological incisal wear facets were artificially created. After every level of induced defect, OCT scanning was performed. B scans were acquired and 3D reconstructions were generated. A swept source OCT instrument is used in this study. The swept source is has a central wavelength of 1050 nm and a sweeping rate of 100 kHz. A depth resolution determined by the swept source of 12 μm in air was experimentally measured. The pathological incisal wear is qualitatively observed on the B-scans as 2D images and 3D reconstructions (volumes). For quantitative evaluations of volumes, we used the Image J software. Our swept source OCT system has several advantages, including the ability to measure (in air) a minimal volume of 2352 μm3 and to collect high resolution volumetric images in 2.5 s. By calculating the areas of the amount of lost tissue corresponding to each difference of B-scans, the final volumes of incisal wear were obtained. This swept source OCT method is very useful for the dynamic evaluation of pathological incisal wear.

  15. Combined in-depth, 3D, en face imaging of the optic disc, optic disc pits and optic disc pit maculopathy using swept-source megahertz OCT at 1050 nm.

    Science.gov (United States)

    Maertz, Josef; Kolb, Jan Philip; Klein, Thomas; Mohler, Kathrin J; Eibl, Matthias; Wieser, Wolfgang; Huber, Robert; Priglinger, Siegfried; Wolf, Armin

    2018-02-01

    To demonstrate papillary imaging of eyes with optic disc pits (ODP) or optic disc pit associated maculopathy (ODP-M) with ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s. To generate 3D-renderings of the papillary area with 3D volume-reconstructions of the ODP and highly resolved en face images from a single densely-sampled megahertz-OCT (MHz-OCT) dataset for investigation of ODP-characteristics. A 1.68 MHz-prototype SS-MHz-OCT system at 1050 nm based on a Fourier-domain mode-locked laser was employed to acquire high-definition, 3D datasets with a dense sampling of 1600 × 1600 A-scans over a 45° field of view. Six eyes with ODPs, and two further eyes with glaucomatous alteration or without ocular pathology are presented. 3D-rendering of the deep papillary structures, virtual 3D-reconstructions of the ODPs and depth resolved isotropic en face images were generated using semiautomatic segmentation. 3D-rendering and en face imaging of the optic disc, ODPs and ODP associated pathologies showed a broad spectrum regarding ODP characteristics. Between individuals the shape of the ODP and the appending pathologies varied considerably. MHz-OCT en face imaging generates distinct top-view images of ODPs and ODP-M. MHz-OCT generates high resolution images of retinal pathologies associated with ODP-M and allows visualizing ODPs with depths of up to 2.7 mm. Different patterns of ODPs can be visualized in patients for the first time using 3D-reconstructions and co-registered high-definition en face images extracted from a single densely sampled 1050 nm megahertz-OCT (MHz-OCT) dataset. As the immediate vicinity to the SAS and the site of intrapapillary proliferation is located at the bottom of the ODP it is crucial to image the complete structure and the whole depth of ODPs. Especially in very deep pits, where non-swept-source OCT fails to reach the bottom, conventional swept-source devices and the MHz-OCT alike are feasible

  16. The radio and optical counterpart of the new Fermi LAT flaring source J0109+6134

    Science.gov (United States)

    Paredes, J. M.; Martí, J.; Peracaula, M.

    2010-02-01

    Following the recent ATELs #2414, #2416 and #2420 concerning the Fermi-LAT, AGILE and Swift/XRT consistent detections of the new gamma-ray flaring source J0109+6134, we wish to remind that the proposed radio counterpart (VCS2 J0109+6133/GT 0106+613) was extensively observed nearly two decades ago by different authors in the context of the GT catalogue of Galactic Plane radio sources (Taylor and Gregory 1983, AJ, 88, 1784; Gregory and Taylor 1986, AJ 92, 371).

  17. Investigation of high-energy sources in optical light by ESA Gaia

    Czech Academy of Sciences Publication Activity Database

    Hudec, R.; Šimon, Vojtěch; Hudec, L.; Hudcová, Věra

    2010-01-01

    Roč. 81, č. 1 (2010), s. 476-481 ISSN 0037-8720. [Multifrequency behaviour of high energy cosmic sources. Vulcano, 25.05.2009-30.05. 2009] R&D Projects: GA ČR GA205/08/1207 Grant - others:ESA(XE) ESA- PECS project No. 98058; GA ČR(CZ) GA102/09/0997; GA MŠk(CZ) ME09027; ESA(XE) ESA- PECS project No. 98023 Institutional research plan: CEZ:AV0Z10030501 Keywords : high-energy sources * cataclysmic variables * low-dispersion spectra Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  18. Imaging of noncarious cervical lesions by means of a fast swept source optical coherence tomography system

    Science.gov (United States)

    Stoica, Eniko T.; Marcauteanu, Corina; Bradu, Adrian; Sinescu, Cosmin; Topala, Florin Ionel; Negrutiu, Meda Lavinia; Duma, Virgil Florin; Podoleanu, Adrian Gh.

    2014-01-01

    Non-carious cervical lesions (NCCL) are defined as the loss of tooth substance at the cemento-enamel junction and are caused by abrasion, erosion and/or occlusal overload. In this paper we proved that our fast swept source OCT system is a valuable tool to track the evolution of NCCL lesions in time. On several extracted bicuspids, four levels of NCCL were artificially created. After every level of induced lesion, OCT scanning was performed. B scans were acquired and 3D reconstructions were generated. The swept source OCT instrument used in this study has a central wavelength of 1050 nm, a sweeping range of 106 nm (measured at 10 dB), an average output power of 16 mW and a sweeping rate of 100 kHz. A depth resolution determined by the swept source of 12 μm in air was experimentally obtained. NCCL were measured on the B-scans as 2D images and 3D reconstructions (volumes). For quantitative evaluations of volumes, the Image J software was used. By calculating the areas of the amount of lost tissue corresponding to each difference of Bscans, the final volumes of NCCL were obtained. This swept source OCT method allows the dynamic diagnosis of NCCL in time.

  19. Monitoring of X-Ray Sources in the Optical Spectral Region

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch

    2010-01-01

    Roč. 2010, - (2010), 382936/1-382936/12 ISSN 1687-7969 R&D Projects: GA ČR GA205/08/1207 Grant - others:ESA(XE) ESA-PECS project No.98058 Institutional research plan: CEZ:AV0Z10030501 Keywords : high-energy sources * microquasars * gamma-ray bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  20. Micro-controller based fiber optic data telemetry system for the ion source of low energy accelerator facility at BARC

    International Nuclear Information System (INIS)

    Padmakumar, Sapna; Ware, Shailaja V.; Subrahmanyam, N.B.V.; Bhatt, J.P.; Singh, S.K.; Gupta, S.K.; Singh, P.; Choudhury, R.K.

    2009-01-01

    The Low Energy Accelerator Facility (LEAF) is a 50 keV, high intensity, negative ion accelerator facility that has been set up indigenously at Nuclear Physics Division, BARC. This facility is capable of delivering a wide range of negative ion beams of both light and heavy ions across the periodic table using a SNICS II (Source of Negative Ion by Caesium Sputtering) source. A micro-controller based control and monitoring system has been developed exclusively for the ion source parameters of LEAF. The data control and monitoring system mainly targets acquiring the data from the field in the terms of parameters such as voltages and currents. There are processes which need to be monitored continuously in order to keep certain parameters under check. The microcontroller based fiber optic data telemetry system allows us to perform the aforesaid task. The voltages can be controlled and monitored by providing the inputs and receiving the feedback through a user friendly graphic user interface. With this system one can control the status as well as analog value of the high voltage power supplies like extractor, cathode, filament, focus line heater and oven. This system consists of Fiber optic transceiver, which is connected on serial port (RS 232C) of microcontroller as well as RS232 port of PC. The whole control system is reliable even in noisy environments including RF and worse EMI conditions. This compact modular design is implemented using low cost devices and allows easy and fast maintainability. In the paper, the details of the system are presented. (author)

  1. Optical identifications of radio sources in the 5C 7 survey

    International Nuclear Information System (INIS)

    Perryman, M.A.C.

    1979-01-01

    An identification procedure developed for the deep radio survey 5C 6 has been refined and applied to the 5C 7 survey. Positions and finding charts are presented for candidate identifications from deep plates taken with the Palomar 48-inch Schmidt telescope. The identification statistics are in good agreement with the 5C 6 results, the accurate radio positions obtained at 1407 MHz defining a reasonably reliable and complete sample of associations with an identification rate of about 40 per cent. At 408 MHz the positional uncertainties are larger and the identifications are thus of lower reliability; the identification rate is about 20 per cent. The results are in good agreement with the assumptions that the optical identifications are coincident with the radio centroids, and that the identifications are not preferentially associated with faint clusters. (author)

  2. A high-flux entanglement source based on a doubly resonant optical parametric amplifier

    International Nuclear Information System (INIS)

    Kuklewicz, Christopher E; Keskiner, Eser; Wong, Franco N C; Shapiro, Jeffrey H

    2002-01-01

    A 532 nm pumped type-II phase-matched, doubly resonant KTP optical parametric amplifier (OPA) was operated near frequency degeneracy to yield an inferred downconverted photon pair production rate of 1.7x10 6 s -1 at a pump power of 100 μW. The OPA output consisted of three components: narrowband doubly resonant mode pairs; narrowband singly resonant mode pairs for which either the signal or idler was resonant with the cavity and broadband nonresonant mode pairs. Under frequency-degenerate operation, the broadband nonresonant mode pairs were polarization triplet states. We observed quantum interference between the orthogonally polarized photons of the triplet states when they were analysed with a polarizer set at 45 deg. relative to the OPA's output polarizations, leading to reduced coincidence counts

  3. Method validation in plasma source optical emission spectroscopy (ICP-OES) - From samples to results

    International Nuclear Information System (INIS)

    Pilon, Fabien; Vielle, Karine; Birolleau, Jean-Claude; Vigneau, Olivier; Labet, Alexandre; Arnal, Nadege; Adam, Christelle; Camilleri, Virginie; Amiel, Jeanine; Granier, Guy; Faure, Joel; Arnaud, Regine; Beres, Andre; Blanchard, Jean-Marc; Boyer-Deslys, Valerie; Broudic, Veronique; Marques, Caroline; Augeray, Celine; Bellefleur, Alexandre; Bienvenu, Philippe; Delteil, Nicole; Boulet, Beatrice; Bourgarit, David; Brennetot, Rene; Fichet, Pascal; Celier, Magali; Chevillotte, Rene; Klelifa, Aline; Fuchs, Gilbert; Le Coq, Gilles; Mermet, Jean-Michel

    2017-01-01

    Even though ICP-OES (Inductively Coupled Plasma - Optical Emission Spectroscopy) is now a routine analysis technique, requirements for measuring processes impose a complete control and mastering of the operating process and of the associated quality management system. The aim of this (collective) book is to guide the analyst during all the measurement validation procedure and to help him to guarantee the mastering of its different steps: administrative and physical management of samples in the laboratory, preparation and treatment of the samples before measuring, qualification and monitoring of the apparatus, instrument setting and calibration strategy, exploitation of results in terms of accuracy, reliability, data covariance (with the practical determination of the accuracy profile). The most recent terminology is used in the book, and numerous examples and illustrations are given in order to a better understanding and to help the elaboration of method validation documents

  4. Nerve Fiber Flux Analysis Using Wide-Field Swept-Source Optical Coherence Tomography.

    Science.gov (United States)

    Tan, Ou; Liu, Liang; Liu, Li; Huang, David

    2018-02-01

    To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT). Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions. There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory. Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans. NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.

  5. Observation of optical properties and sources of aerosols at Buddha's birthplace, Lumbini, Nepal: environmental implications.

    Science.gov (United States)

    Rupakheti, Dipesh; Kang, Shichang; Rupakheti, Maheswar; Cong, Zhiyuan; Tripathee, Lekhendra; Panday, Arnico K; Holben, Brent N

    2018-03-15

    For the first time, aerosol optical properties are measured over Lumbini, Nepal, with CIMEL sunphotometer of the Aerosol Robotic Network (AERONET) program. Lumbini is a sacred place as the birthplace of Lord Buddha, and thus a UNESCO world heritage site, located near the northern edge of the central Indo-Gangetic Plains (IGP) and before the Himalayan foothills (and Himalayas) to its north. Average aerosol optical depth (AOD) is found to be 0.64 ± 0.38 (0.06-3.28) over the sampling period (January 2013-December 2014), with the highest seasonal AOD during the post-monsoon season (0.72 ± 0.44). More than 80% of the daily averaged AOD values, during the monitoring period, are above 0.3, indicating polluted conditions in the region. The levels of aerosol load observed over Lumbini are comparable to those observed at several heavily polluted sites in the IGP. Based on the relationship between AOD and Ångstrom exponent (α), anthropogenic, biomass burning, and mixed aerosols are found to be the most prevalent aerosol types. The aerosol volume-size distribution is bi-modal during all four seasons with modes centered at 0.1-0.3 and 3-4 μm. For both fine and coarse modes, the highest volumetric concentration of ~ 0.08 μm -3  μm -2 is observed during the post-monsoon and pre-monsoon seasons. As revealed by the single-scattering albedo (SSA), asymmetry parameter (AP), and refractive index (RI) analyses, aerosol loading over Lumbini is dominated by absorbing, urban-industrial, and biomass burning aerosols.

  6. Off-axis full-field swept-source optical coherence tomography using holographic refocusing

    Science.gov (United States)

    Hillmann, Dierck; Franke, Gesa; Hinkel, Laura; Bonin, Tim; Koch, Peter; Hüttmann, Gereon

    2013-03-01

    We demonstrate a full-field swept-source OCT using an off-axis geometry of the reference illumination. By using holographic refocusing techniques, a uniform lateral resolution is achieved over the measurement depth of approximately 80 Rayleigh lengths. Compared to a standard on-axis setup, artifacts and autocorrelation signals are suppressed and the measurement depth is doubled by resolving the complex conjugate ambiguity. Holographic refocusing was done efficiently by Fourier-domain resampling as demonstrated before in inverse scattering and holoscopy. It allowed to reconstruct a complete volume with about 10μm resolution over the complete measurement depth of more than 10mm. Off-axis full-field swept-source OCT enables high measurement depths, spanning many Rayleigh lengths with reduced artifacts.

  7. Color-color analysis of the optical counterparts of high energy sources

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, René; Pizzichini, G.

    2010-01-01

    Roč. 81, č. 1 (2010), s. 356-361 ISSN 0037-8720. [Multifrequency behaviour of high energy cosmic sources. Vulcano, 25.05.2009-30.05. 2009] R&D Projects: GA ČR GA205/08/1207 Grant - others:ESA(XE) ESA- PECS project No. 98058 Institutional research plan: CEZ:AV0Z10030501 Keywords : X-rays binaries * gamma rays * accretion, accretion disks Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  8. Exploration of the Challenges of Neutron Optics and Instrumentation at Long Pulsed Spallation Sources

    DEFF Research Database (Denmark)

    Klenø, Kaspar Hewitt

    In this thesis I have explored the challenges of long guides and instrumentation for the long pulsed European Spallation Source. I have derived the theory needed for quantifying the performance of a guide using brilliance transfer. With this tool it is easier to objectively compare how well diffe...... the simulations and optimisations of one particular instrument, the Compact SANS, on which I have worked on the design of the guide, collimation, and chopper systems....

  9. Tomography feasibility study on the optical emission spectroscopy diagnostic for the negative ion source of the ELISE test facility

    International Nuclear Information System (INIS)

    Bonomo, F; Agostini, M; Brombin, M; Pasqualotto, R; Fantz, U; Franzen, P; Wünderlich, D

    2014-01-01

    A feasibility study of a spectroscopic tomographic diagnostic for the emissivity reconstruction of the plasma parameters in the large negative ion source of the test facility ELISE is described. Tomographic tools are developed to be applied to the measurements of the ELISE optical emission spectroscopy (OES) diagnostic, in order to reconstruct the emissivity distribution from hydrogen (or deuterium) plasma close to the plasma grid, where negative ions are produced and extracted to be accelerated. Various emissivity phantoms, both symmetric and asymmetric, reproducing different plasma experimental conditions have been simulated to test the tomographic algorithm. The simultaneous algebraic reconstruction technique has been applied, accounting for the OES geometrical layout together with a suitable pixel representation. Even with a limited number of 14 lines of sight (LoSs), the plasma emissivity distribution expected on the ELISE source can be successfully reconstructed. In particular, asymmetries in the emissivity pattern can be detected and reproduced with low errors. A systematic investigation of different geometrical layouts of the LoSs as well as of the pixel arrangements has been carried out, and a final configuration has been identified. Noise on the simulated experimental spectroscopic measurements has been tested, confirming the reliability of the adopted tomographic tools for the plasma emissivity reconstructions of the source plasma in ELISE with the actual OES diagnostic system. (paper)

  10. Mass estimates from optical-light curves for binary X-ray sources

    International Nuclear Information System (INIS)

    Avni, Y.

    1978-01-01

    The small amplitude variations with orbital phase of the optical light from X-ray binaries are caused by the changing geometrical aspect of the primary as seen by a fixed observer. The shape and the amplitude of the light curve depends on the stellar masses and on the orbital elements. The light curve can, therefore, be used to determine, or set limits on, the parameters of the binary system. A self-consistent procedure for the calculation of the light curve can be formulated if the primary is formulated if the primary is uniformly rotating at an angular velocity equal to the angular velocity of its orbital revolution in a circular orbit, and if the primary is in a hydrostatic and radiative equilibrium in the co-rotating frame. When the primary is further approximated to be centrally condensed, the above set of assumptions is called the standard picture. The standard picture is described, its validity discussed and its application to various systems reviewed. (C.F.)

  11. Agreement between Gonioscopic Examination and Swept Source Fourier Domain Anterior Segment Optical Coherence Tomography Imaging

    Directory of Open Access Journals (Sweden)

    Mohammed Rigi

    2016-01-01

    Full Text Available Purpose. To evaluate interobserver, intervisit, and interinstrument agreements for gonioscopy and Fourier domain anterior segment optical coherence tomography (FD ASOCT for classifying open and narrow angle eyes. Methods. Eighty-six eyes with open or narrow anterior chamber angles were included. The superior angle was classified open or narrow by 2 of 5 glaucoma specialists using gonioscopy and imaged by FD ASOCT in the dark. The superior angle of each FD ASOCT image was graded as open or narrow by 2 masked readers. The same procedures were repeated within 6 months. Kappas for interobserver and intervisit agreements for each instrument and interinstrument agreements were calculated. Results. The mean age was 50.9 (±18.4 years. Interobserver agreements were moderate to good for both gonioscopy (0.57 and 0.69 and FD ASOCT (0.58 and 0.75. Intervisit agreements were moderate to excellent for both gonioscopy (0.53 to 0.86 and FD ASOCT (0.57 and 0.85. Interinstrument agreements were fair to good (0.34 to 0.63, with FD ASOCT classifying more angles as narrow than gonioscopy. Conclusions. Both gonioscopy and FD ASOCT examiners were internally consistent with similar interobserver and intervisit agreements for angle classification. Agreement between instruments was fair to good, with FD ASOCT classifying more angles as narrow than gonioscopy.

  12. Agreement between Gonioscopic Examination and Swept Source Fourier Domain Anterior Segment Optical Coherence Tomography Imaging

    Science.gov (United States)

    Nguyen, Donna; Minnal, Vandana R.

    2016-01-01

    Purpose. To evaluate interobserver, intervisit, and interinstrument agreements for gonioscopy and Fourier domain anterior segment optical coherence tomography (FD ASOCT) for classifying open and narrow angle eyes. Methods. Eighty-six eyes with open or narrow anterior chamber angles were included. The superior angle was classified open or narrow by 2 of 5 glaucoma specialists using gonioscopy and imaged by FD ASOCT in the dark. The superior angle of each FD ASOCT image was graded as open or narrow by 2 masked readers. The same procedures were repeated within 6 months. Kappas for interobserver and intervisit agreements for each instrument and interinstrument agreements were calculated. Results. The mean age was 50.9 (±18.4) years. Interobserver agreements were moderate to good for both gonioscopy (0.57 and 0.69) and FD ASOCT (0.58 and 0.75). Intervisit agreements were moderate to excellent for both gonioscopy (0.53 to 0.86) and FD ASOCT (0.57 and 0.85). Interinstrument agreements were fair to good (0.34 to 0.63), with FD ASOCT classifying more angles as narrow than gonioscopy. Conclusions. Both gonioscopy and FD ASOCT examiners were internally consistent with similar interobserver and intervisit agreements for angle classification. Agreement between instruments was fair to good, with FD ASOCT classifying more angles as narrow than gonioscopy. PMID:27990300

  13. Optical studies of UHURU sources. XIII. A photometric analysis of X Persei (=3U 0352+30)

    International Nuclear Information System (INIS)

    Gottlieb, E.W.; Wright, E.L.; Liller, W.

    1975-01-01

    2677 magnitudes of the hot massive variable star X Persei, the prime optical candidate for the X-ray source 3U 0352+30, have been obtained from blue plates in the Harvard collection taken between 1894.9 and 1975.1. These data have been analyzed for periods from 0.5 to 180 days and find no periodic component of brightness with full sinusoidal amplitude greater than or equal to0.05 mag. Other period searches, from 550 to 618 days and from 10.75 to 11.75 hours, likewise gave negative results for full amplitudes of greater than or equal to0.07 mag. The mean light curve is published and its properties are discussed

  14. Simultaneous optical coherence tomography and lipofuscin autofluorescence imaging of the retina with a single broadband light source at 480nm.

    Science.gov (United States)

    Jiang, Minshan; Liu, Tan; Liu, Xiaojing; Jiao, Shuliang

    2014-12-01

    We accomplished spectral domain optical coherence tomography and auto-fluorescence microscopy for imaging the retina with a single broadband light source centered at 480 nm. This technique is able to provide simultaneous structural imaging and lipofuscin molecular contrast of the retina. Since the two imaging modalities are provided by the same group of photons, their images are intrinsically registered. To test the capabilities of the technique we periodically imaged the retinas of the same rats for four weeks. The images successfully demonstrated lipofuscin accumulation in the retinal pigment epithelium with aging. The experimental results showed that the dual-modal imaging system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  15. Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Maria [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico); Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2732, BC 22860 Ensenada (Mexico); Garay-Palmett, Karina; U' Ren, Alfred B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico)

    2011-09-15

    We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.

  16. Design and commissioning of the photon monitors and optical transport lines for the advanced photon source positron accumulator ring

    International Nuclear Information System (INIS)

    Berg, W.; Yang, B.; Lumpkin, A.; Jones, J.

    1996-01-01

    Two photon monitors have been designed and installed in the positron accumulator ring (PAR) of the Advanced Photon Source. The photon monitors characterize the beam's transverse profile, bunch length, emittance, and energy spread in a nonintrusive manner. An optical transport line delivers synchrotron light from the PAR out of a high radiation environment. Both charge-coupled device and fast-gated, intensified cameras are used to measure the transverse beam profile (0.11 - 1 mm for damped beam) with a resolution of 0.06 mm. A streak camera (θ τ =I ps) is used to measure the bunch length which is in the range of 0.3-1 ns. The design of the various transport components and commissioning results of the photon monitors will be discussed

  17. Spin exchange optical pumping based polarized 3He filling station for the Hybrid Spectrometer at the Spallation Neutron Source.

    Science.gov (United States)

    Jiang, C Y; Tong, X; Brown, D R; Culbertson, H; Graves-Brook, M K; Hagen, M E; Kadron, B; Lee, W T; Robertson, J L; Winn, B

    2013-06-01

    The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60° horizontal and 15° vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized (3)He filling station based on the spin exchange optical pumping method. It is designed to supply polarized (3)He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the (3)He pressure with respect to the scattered neutron energies. The depolarized (3)He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

  18. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    International Nuclear Information System (INIS)

    Sloan Roberts, F.; Anderson, Scott L.

    2013-01-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry

  19. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    Energy Technology Data Exchange (ETDEWEB)

    Sloan Roberts, F.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)

    2013-12-15

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry.

  20. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source.

    Science.gov (United States)

    Roberts, F Sloan; Anderson, Scott L

    2013-12-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

  1. Optical properties of organic-silicon photonic crystal nanoslot cavity light source

    Directory of Open Access Journals (Sweden)

    Ming-Jay Yang

    2017-03-01

    Full Text Available We theoretically study a dielectric photonic crystal nanoslot cavity immersed in an organic fluid containing near-infrared dyes by means of a full rate equation model including the complete cavity QED effects. Based on the modeling results, we numerically design an organic-silicon cavity light source in which its mode volume, quality factor, and far-field emission pattern are optimized for energy-efficient, high-speed applications. Dye quantum efficiency improved by two orders of magnitude and 3dB modulation bandwidth of a few hundred GHz can be obtained.

  2. Integrated Wavelength-Tunable Light Source for Optical Gas Sensing Systems

    Directory of Open Access Journals (Sweden)

    Bin Li

    2015-01-01

    Full Text Available A compact instrument consisting of a distributed feedback laser (DFB at 1.65 μm was developed as a light source for gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS technique. The wavelength of laser is tuned by adjusting the laser working temperature and injection current, which are performed by self-developed temperature controller and current modulator respectively. Stability test shows the fluctuation of the laser temperature is within the range of ±0.02°C. For gas detection experiments, the wavelength is tuned around the gas absorption line by adjusting laser temperature and is then shifted periodically to scan across the absorption line by the laser current modulator, which generates a 10 Hz saw wave signal. In addition, the current modulator is able to generate sine wave signal for gas sensing systems using wavelength modulation spectroscopy (WMS technique involving extraction of harmonic signals. The spectrum test proves good stability that the spectrum was measured 6 times every 10 minutes at the constant temperature and current condition. This standalone instrument can be applied as a light source for detection systems of different gases by integrating lasers at corresponding wavelength.

  3. Vacuum source-field correlations and advanced waves in quantum optics

    Directory of Open Access Journals (Sweden)

    Adam Stokes

    2018-01-01

    Full Text Available The solution to the wave equation as a Cauchy problem with prescribed fields at an initial time $t=0$ is purely retarded. Similarly, in the quantum theory of radiation the specification of Heisenberg picture photon annihilation and creation operators at time $t \\gt 0$ in terms of operators at $t=0$ automatically yields purely retarded source-fields. However, we show that two-time quantum correlations between the retarded source-fields of a stationary dipole and the quantum vacuum-field possess advanced wave-like contributions. Despite their advanced nature, these correlations are perfectly consistent with Einstein causality. It is shown that while they do not significantly contribute to photo-detection amplitudes in the vacuum state, they do effect the statistics of measurements involving the radiative force experienced by a point charge in the field of the dipole. Specifically, the dispersion in the charge's momentum is found to increase with time. This entails the possibility of obtaining direct experimental evidence for the existence of advanced waves in physical reality, and provides yet another signature of the quantum nature of the vacuum.

  4. Compensating the electron beam energy spread by the natural transverse gradient of laser undulator in all-optical x-ray light sources.

    Science.gov (United States)

    Zhang, Tong; Feng, Chao; Deng, Haixiao; Wang, Dong; Dai, Zhimin; Zhao, Zhentang

    2014-06-02

    All-optical ideas provide a potential to dramatically cut off the size and cost of x-ray light sources to the university-laboratory scale, with the combination of the laser-plasma accelerator and the laser undulator. However, the large longitudinal energy spread of the electron beam from laser-plasma accelerator may hinder the way to high brightness of these all-optical light sources. In this paper, the beam energy spread effect is proposed to be significantly compensated by the natural transverse gradient of a laser undulator when properly transverse-dispersing the electron beam. Theoretical analysis and numerical simulations on conventional laser-Compton scattering sources and high-gain all-optical x-ray free-electron lasers with the electron beams from laser-plasma accelerators are presented.

  5. Spectroscopic Determination of the Physical Conditions in Hot Optically Thin Sources

    Science.gov (United States)

    Oliversen, Ronald J. (Technical Monitor); Brickhouse, Nancy

    2004-01-01

    Astrophysical Plasma Emission Database - APED consists of atomic data, primarily theoretical, needed to calculate X-ray through optical emission spectra of hot thermal plasmas. These data are supplemented by experimental values, such as laboratory plasma wave- lengths, and are validated by experiment only rarely. Thus the comparison of predicted spectra to astrophysical spectra serves as invaluable feedback on the quality of the models. Following up on unfavorable comparisons, we have communicated atomic data needs to atomic theorists and experimental plasma physicists so that improvements can be made to the database. The database is now reasonably complete from approx. 1 to 30 A, and from - 90 to 180 A, with significant gaps remaining in the range 30 to 90 A. Astrophysical Plasma Emission Code - APEC uses the APED data as inputs and computes level populations and line emissivities using a rate matrix solver. Tabulated models for a fine grid of temperatures and densities can be applied to observational data. The current public version of APEC output uses an input ionization balance model, assuming CIE; however, we have a working version to calculate the ionization state of the gas. We will begin testing non-equilibrium ionization (NEI) models over the next year - we are now finalizing the atomic database needed to perform the ionization state calculations. At that time, the code will be made public. We have developed optimized error codes, additional testing protocols and substantial documentation, in preparation for this public release. Secondarily, we have begun to investigate the use of APED and APEC for X-ray photoionized plasma, beginning with opacity modeling (e.g. warm absorbers). Application to bright AGN Chandra grating spectra suggests that the accurate wavelengths in APED are of great importance to fitting the data. We are exploring additional subroutines to APEC to extend its usefulness for X-ray photoionized plasma, e.g. to include collisional or photo

  6. Optically controlled laser-plasma electron accelerator for compact gamma-ray sources

    Science.gov (United States)

    Kalmykov, S. Y.; Davoine, X.; Ghebregziabher, I.; Shadwick, B. A.

    2018-02-01

    Generating quasi-monochromatic, femtosecond γ-ray pulses via Thomson scattering (TS) demands exceptional electron beam (e-beam) quality, such as percent-scale energy spread and five-dimensional brightness over 1016 A m-2. We show that near-GeV e-beams with these metrics can be accelerated in a cavity of electron density, driven with an incoherent stack of Joule-scale laser pulses through a mm-size, dense plasma (n 0 ˜ 1019 cm-3). Changing the time delay, frequency difference, and energy ratio of the stack components controls the e-beam phase space on the femtosecond scale, while the modest energy of the optical driver helps afford kHz-scale repetition rate at manageable average power. Blue-shifting one stack component by a considerable fraction of the carrier frequency makes the stack immune to self-compression. This, in turn, minimizes uncontrolled variation in the cavity shape, suppressing continuous injection of ambient plasma electrons, preserving a single, ultra-bright electron bunch. In addition, weak focusing of the trailing component of the stack induces periodic injection, generating, in a single shot, a train of bunches with controllable energy spacing and femtosecond synchronization. These designer e-beams, inaccessible to conventional acceleration methods, generate, via TS, gigawatt γ-ray pulses (or multi-color pulse trains) with the mean energy in the range of interest for nuclear photonics (4-16 MeV), containing over 106 photons within a microsteradian-scale observation cone.

  7. Comparison of retina specialist preferences regarding spectral-domain and swept-source optical coherence tomography angiography

    Directory of Open Access Journals (Sweden)

    Su GL

    2017-05-01

    Full Text Available Grace L Su,1 Douglas M Baughman,2 Qinqin Zhang,3 Kasra Rezaei,2 Aaron Y Lee,2 Cecilia S Lee2 1Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 2Department of Ophthalmology, 3Department of Bioengineering, University of Washington, Seattle, WA, USA Purpose: The aim of this study was to compare physician preferences regarding the commercially available spectral-domain (SD optical coherence tomography angiography (OCTA and swept-source (SS OCTA prototype device.Design: Comparative analysis of diagnostic instruments was performed.Patients and methods: Subjects at the University of Washington Eye Institute and Harborview Medical Center were prospectively recruited and imaged with the Zeiss SD OCTA (HD-5000, Angioplex and Zeiss SS OCTA (Plex Elite, Everest devices on the same day. The study included 10 eyes from 10 subjects diagnosed with a retinal/choroidal disease. Deidentified images were compiled into a survey and sent to retina specialists in various countries. The survey presented masked SD and SS images of each eye for each retinal sublayer side by side. Respondents were asked about their image preference and impact on clinical management. A priori and post hoc preferences for SD vs SS were collected.Results: Fifty-four retina specialists responded to the survey. Median years in practice was 3.00 (interquartile range [IQR] 1.50–17.00. At baseline, 23 (48% physicians owned an OCTA machine. The majority of physician responses showed a preference for the SS over SD OCTA, independent of the retinal pathology shown (n=454 overall responses, 74%. Nevertheless, the majority indicated that both SD and SS would be equally valuable in informing clinical decisions (n=374 overall responses, 61%.Conclusion: These findings indicate that the majority of retina specialists surveyed prefer SS over SD OCTA based on image quality, regardless of the retinal pathology shown. Regarding the clinical utility of each modality, the majority of

  8. Gas pressure of extractive system from the high power ion source and effect of compound materials on the optical characteristics of ion

    International Nuclear Information System (INIS)

    Pan Zudong; Chen Miaosun; Wang Shouhu; Chen Xingqin; Ge Yisan; Fu Peng

    1991-01-01

    The mechanism of extractive beam from the ion source and the ion optical condition of a minimal divergence angle were introduced briefly. Two problems in researching 15 cm Duo Penning Ion Source (extractive voltage-25 kV, current-20 A) are expounded: (1) The pulse admission way makes the extractive system keeping optimum vacuum; (2) The insulating rings are made of a compound material, therefore, insulating characteristic is improved. Both the described points (1) and (2) will make a contribution to the ion optics

  9. Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging.

    Science.gov (United States)

    Lu, Chen D; Waheed, Nadia K; Witkin, Andre; Baumal, Caroline R; Liu, Jonathan J; Potsaid, Benjamin; Joseph, Anthony; Jayaraman, Vijaysekhar; Cable, Alex; Chan, Kinpui; Duker, Jay S; Fujimoto, James G

    2018-02-01

    To demonstrate the feasibility of retinal and anterior segment intraoperative widefield imaging using an ultrahigh-speed, swept-source optical coherence tomography (SS-OCT) surgical microscope attachment. A prototype post-objective SS-OCT using a 1,050-nm wavelength, 400 kHz A-scan rate, vertical cavity surface-emitting laser (VCSEL) light source was integrated to a commercial ophthalmic surgical microscope after the objective. Each widefield OCT data set was acquired in 3 seconds (1,000 × 1,000 A-scans, 12 × 12 mm 2 for retina and 10 × 10 mm 2 for anterior segment). Intraoperative SS-OCT was performed in 20 eyes of 20 patients. In six of seven membrane peels and five of seven rhegmatogenous retinal detachment repair surgeries, widefield retinal imaging enabled evaluation pre- and postoperatively. In all seven cataract cases, anterior imaging evaluated the integrity of the posterior lens capsule. Ultrahigh-speed SS-OCT enables widefield intraoperative viewing in the posterior and anterior eye. Widefield imaging visualizes ocular structures and pathology without requiring OCT realignment. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:94-102.]. Copyright 2018, SLACK Incorporated.

  10. Optimisation of a polygon mirror-based spectral filter for swept source optical coherence tomography (SS-OCT)

    Science.gov (United States)

    Everson, Michael; Duma, Virgil-Florin; Dobre, George

    2018-03-01

    Medical imaging using Optical Coherence Tomography (OCT) provides clinicians with 3D, high resolution reconstructions of microscopic structures, in depth. It has been initially developed for ophthalmology, in order to scan the retinas of patients to diagnose illness. The quality of the images depends upon their axial and lateral resolutions and the properties of the light being used. Research using a polygon mirror (PM) as a spectral filter in Swept Source OCT (SS-OCT) has resulted in a variety of different experimental arrangements. Although the application of PM-based SS-OCT sources has been successfully demonstrated, the combination of their components' fundamental properties and the overall impact they have on imaging performance is rarely reported. A more detailed examination of these properties would lead to a full description of their operation and to the best methods to employ if system performance is to be maximised. This work presents our current findings of on-going research into the optimisation of PM-based SS-OCT systems. A swept source spectral filter, consisting of a collimator, a transmission grating, a two-lens telescope and an off-axis PM with an end reflector mirror has been evaluated experimentally and compared with theoretical predictions. The system's performance has been compared for two different fibre collimators. Although the beam width on the grating is different for each of the two collimators, the spot size at the PM facet is made the same by selecting appropriate focal lengths. An improvement in the signal roll-off at the interferometer output of 1.0 dB/mm was obtained when using a 3.4 mm collimator compared to a 1.5 mm collimator.

  11. Defense of fake fingerprint attacks using a swept source laser optical coherence tomography setup

    Science.gov (United States)

    Meissner, Sven; Breithaupt, Ralph; Koch, Edmund

    2013-03-01

    The most established technique for the identification at biometric access control systems is the human fingerprint. While every human fingerprint is unique, fingerprints can be faked very easily by using thin layer fakes. Because commercial fingerprint scanners use only a two-dimensional image acquisition of the finger surface, they can only hardly differentiate between real fingerprints and fingerprint fakes applied on thin layer materials. A Swept Source OCT system with an A-line rate of 20 kHz and a lateral and axial resolution of approximately 13 μm, a centre wavelength of 1320 nm and a band width of 120 nm (FWHM) was used to acquire fingerprints and finger tips with overlying fakes. Three-dimensional volume stacks with dimensions of 4.5 mm x 4 mm x 2 mm were acquired. The layering arrangement of the imaged finger tips and faked finger tips was analyzed and subsequently classified into real and faked fingerprints. Additionally, sweat gland ducts were detected and consulted for the classification. The manual classification between real fingerprints and faked fingerprints results in almost 100 % correctness. The outer as well as the internal fingerprint can be recognized in all real human fingers, whereby this was not possible in the image stacks of the faked fingerprints. Furthermore, in all image stacks of real human fingers the sweat gland ducts were detected. The number of sweat gland ducts differs between the test persons. The typical helix shape of the ducts was observed. In contrast, in images of faked fingerprints we observe abnormal layer arrangements and no sweat gland ducts connecting the papillae of the outer fingerprint and the internal fingerprint. We demonstrated that OCT is a very useful tool to enhance the performance of biometric control systems concerning attacks by thin layer fingerprint fakes.

  12. Full-asynchronous gigabit-symmetric DPSK downstream and OOK upstream OCDMA-PON with source-free ONUs employing all-optical self-clocked time gate.

    Science.gov (United States)

    Dai, Bo; Shimizu, Satoshi; Wang, Xu; Wada, Naoya

    2012-12-10

    We propose an asynchronous gigabit-symmetric optical code division multiplexing access passive optical network (OCDMA-PON) in which optical network units (ONUs) are source-free. In the experiment, we demonstrate a duplex OCDMA system with a 50 km 10 Gbit/s/user 4-user DPSK-OCDMA downlink and a 50 km 10 Gbit/s/user 4-user OOK-OCDMA uplink and error-free duplex transmissions are achieved. Besides, we investigate an all-optical self-clocked time gate, which is used for the signal regeneration of decoded signals and ensures asynchronization in the up/downstream transmissions. Furthermore, we evaluate the power budget of the proposed duplex transmission.

  13. Feasibility of using a high power CO2 laser as an alternative source to test high heat load x-ray optics

    International Nuclear Information System (INIS)

    Fernandez, P.B.

    1993-01-01

    To determine the feasibility of using the CO 2 laser at LAL as an alternative heat source for x-ray optics tests, we have studied the absorption of the 10.6-micron laser light in silicon for two different dopant concentrations, using the resistivity as a predictor for the absorption length. We describe the results from these tests in this report

  14. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    International Nuclear Information System (INIS)

    Panitzsch, Lauri

    2013-01-01

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet (∼45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to other

  15. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Panitzsch, Lauri

    2013-02-08

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet ({approx}45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to

  16. Swept source optical coherence tomography for in vivo imaging and vibrometry in the apex of the mouse cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Yoon [E.L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California (United States); Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California (United States); Raphael, Patrick D.; Oghalai, John S. [Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California (United States); Ellerbee, Audrey K. [E.L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California (United States); Applegate, Brian E. [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States)

    2015-12-31

    Cochlear amplification has been most commonly investigated by measuring the vibrations of the basilar membrane in animal models. Several different techniques have been used for measuring these vibrations such as laser Doppler vibrometry, miniature pressure sensors, low coherence interferometry, and spectral-domain optical coherence tomography (SD-OCT). We have built a swept-source OCT (SS-OCT) system, which is similar to SD-OCT in that it is capable of performing both imaging and vibration measurements within the mouse cochlea in vivo without having to open the bone. In vivo 3D images of a mouse cochlea were obtained, and the basilar membrane, tectorial membrane, Reissner’s membrane, tunnel of Corti, and reticular lamina could all be resolved. We measured vibrations of multiple structures within the mouse cochlea to sound stimuli. As well, we measured the radial deflections of the reticular lamina and tectorial membrane to estimate the displacement of the outer hair cell stereocilia. These measurements have the potential to more clearly define the mechanisms underlying the linear and non-linear processes within the mammalian cochlea.

  17. Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system

    Science.gov (United States)

    Alonso-Caneiro, David; Karnowski, Karol; Kaluzny, Bartlomiej J.; Kowalczyk, Andrzej; Wojtkowski, Maciej

    2011-07-01

    We present a novel method and instrument for in vivo imaging and measurement of the human corneal dynamics during an air puff. The instrument is based on high-speed swept source optical coherence tomography (ssOCT) combined with a custom adapted air puff chamber from a non-contact tonometer, which uses an air stream to deform the cornea in a non-invasive manner. During the short period of time that the deformation takes place, the ssOCT acquires multiple A-scans in time (M-scan) at the center of the air puff, allowing observation of the dynamics of the anterior and posterior corneal surfaces as well as the anterior lens surface. The dynamics of the measurement are driven by the biomechanical properties of the human eye as well as its intraocular pressure. Thus, the analysis of the M-scan may provide useful information about the biomechanical behavior of the anterior segment during the applanation caused by the air puff. An initial set of controlled clinical experiments are shown to comprehend the performance of the instrument and its potential applicability to further understand the eye biomechanics and intraocular pressure measurements. Limitations and possibilities of the new apparatus are discussed.

  18. Accurately computing the optical pathlength difference for a michelson interferometer with minimal knowledge of the source spectrum.

    Science.gov (United States)

    Milman, Mark H

    2005-12-01

    Astrometric measurements using stellar interferometry rely on precise measurement of the central white light fringe to accurately obtain the optical pathlength difference of incoming starlight to the two arms of the interferometer. One standard approach to stellar interferometry uses a channeled spectrum to determine phases at a number of different wavelengths that are then converted to the pathlength delay. When throughput is low these channels are broadened to improve the signal-to-noise ratio. Ultimately the ability to use monochromatic models and algorithms in each of the channels to extract phase becomes problematic and knowledge of the spectrum must be incorporated to achieve the accuracies required of the astrometric measurements. To accomplish this an optimization problem is posed to estimate simultaneously the pathlength delay and spectrum of the source. Moreover, the nature of the parameterization of the spectrum that is introduced circumvents the need to solve directly for these parameters so that the optimization problem reduces to a scalar problem in just the pathlength delay variable. A number of examples are given to show the robustness of the approach.

  19. A high-significance measurement of correlation between unresolved IRAS sources and optically-selected galaxy clusters

    Energy Technology Data Exchange (ETDEWEB)

    Hincks, Adam D.; Hajian, Amir [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Addison, Graeme E., E-mail: hincks@cita.utoronto.ca, E-mail: ahajian@cita.utoronto.ca, E-mail: gaddison@phas.ubc.ca [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada)

    2013-05-01

    We cross-correlate the 100 μm Improved Reprocessing of the IRAS Survey (IRIS) map and galaxy clusters at 0.1 < z < 0.3 in the maxBCG catalogue taken from the Sloan Digital Sky Survey, measuring an angular cross-power spectrum over multipole moments 150 < l < 3000 at a total significance of over 40σ. The cross-spectrum, which arises from the spatial correlation between unresolved dusty galaxies that make up the cosmic infrared background (CIB) in the IRIS map and the galaxy clusters, is well-fit by a single power law with an index of −1.28±0.12, similar to the clustering of unresolved galaxies from cross-correlating far-infrared and submillimetre maps at longer wavelengths. Using a recent, phenomenological model for the spectral and clustering properties of the IRIS galaxies, we constrain the large-scale bias of the maxBCG clusters to be 2.6±1.4, consistent with existing analyses of the real-space cluster correlation function. The success of our method suggests that future CIB-optical cross-correlations using Planck and Herschel data will significantly improve our understanding of the clustering and redshift distribution of the faint CIB sources.

  20. Comparison of choroidal thickness using swept-source and spectral-domain optical coherence tomography in normal Indian eyes.

    Science.gov (United States)

    Narendran, Siddharth; Manayath, George; Venkatapathy, Narendran

    2018-01-01

    Choroidal thickness measurements are reported to differ between spectral-domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT). The aim of this study was to assess the comparability of choroidal thickness measurements using SS-OCT and SD-OCT devices among normal participants. This was a prospective study of 31 (62 eyes) normal participants. Choroidal imaging was performed sequentially with the Spectralis OCT (SD-OCT) and the deep range imaging OCT (DRI OCT-1) (SS-OCT) using standardized imaging protocols. The subfoveal choroidal thickness (SFChT) was measured manually by two masked retinal specialists. Paired t -tests and intraclass correlation coefficients (ICCs) were used to compare the measurements. The mean SFChT was 319.5 μm and 325.3 μm for DRI OCT-1 and Spectralis OCT, respectively ( P = 0.001), with a mean difference of 5.9 with ICC of 0.97. The mean difference in choroidal thickness between the OCT devices was larger among eyes with choroidal thickness > 350 μm compared with eyes with thinner choroids (8.0 μm vs. 4.7 μm). SFChT measurements are comparable between DRI OCT-1 and Spectralis OCT. The variability between the devices increases in thicker choroids.

  1. Repeatability of swept-source optical coherence tomography retinal and choroidal thickness measurements in neovascular age-related macular degeneration

    DEFF Research Database (Denmark)

    Hanumunthadu, Daren; Ilginis, Tomas; Restori, Marie

    2017-01-01

    BACKGROUND: The aim was to determine the intrasession repeatability of swept-source optical coherence tomography (SS-OCT)-derived retinal and choroidal thickness measurements in eyes with neovascular age-related macular degeneration (nAMD). METHODS: A prospective study consisting of patients...... with active nAMD enrolled in the Distance of Choroid Study at Moorfields Eye Hospital, London. Patients underwent three 12×9 mm macular raster scans using the deep range imaging (DRI) OCT-1 SS-OCT (Topcon) device in a single imaging session. Retinal and choroidal thicknesses were calculated for the ETDRS...... macular subfields. Repeatability was calculated according to methods described by Bland and Altman. RESULTS: 39 eyes of 39 patients with nAMD were included with a mean (±SD) age of 73.9 (±7.2) years. The mean (±SD) retinal thickness of the central macular subfield was 225.7 μm (±12.4 μm...

  2. OPERATIONAL EXPERIENCE WITH FAST FIBER-OPTIC BEAM LOSS MONITORS FOR THE ADVANCED PHOTON SOURCE STORAGE RING SUPERCONDUCTING UNDULATORS

    Energy Technology Data Exchange (ETDEWEB)

    Dooling, J.; Harkay, K.; Sajaev, V.; Shang, H.

    2017-06-25

    Fast fiber-optic (FFO) beam loss monitors (BLMs) installed with the first two superconducting undulators (SCUs) in the Advanced Photon Source storage ring have proven to be a useful diagnostic for measuring deposited charge (energy) during rapid beam loss events. The first set of FFOBLMs were installed outside the cryostat of the short SCU, a 0.33-m long device, above and below the beam centerline. The second set are mounted with the first 1.1-mlong SCU within the cryostat, on the outboard and inboard sides of the vacuum chamber. The next 1.1-m-long SCU is scheduled to replace the short SCU later in 2016 and will be fitted with FFOBLMs in a manner similar to original 1.1-m device. The FFOBLMs were employed to set timing and voltage for the abort kicker (AK) system. The AK helps to prevent quenching of the SCUs during beam dumps [1] by directing the beam away from the SC magnet windings. The AK is triggered by the Machine Protection System (MPS). In cases when the AK fails to prevent quenching, the FFOBLMs show that losses often begin before detection by the MPS.

  3. Anterior chamber angle imaging with swept-source optical coherence tomography: measuring peripheral anterior synechia in glaucoma.

    Science.gov (United States)

    Lai, Isabel; Mak, Heather; Lai, Gilda; Yu, Marco; Lam, Dennis S C; Leung, Christopher K S

    2013-06-01

    To investigate the use of swept-source optical coherence tomography (OCT) for measuring the area and degree of peripheral anterior synechia (PAS) involvement in patients with angle-closure glaucoma. Cross-sectional study. Twenty-three eyes with PAS (detected by indentation gonioscopy) from 20 patients with angle-closure glaucoma (20 eyes had primary angle-closure glaucoma and 3 eyes had angle-closure glaucoma secondary to chronic anterior uveitis [n = 2] and Axenfeld-Rieger syndrome [n = 1]). The anterior chamber angles were evaluated with indentation gonioscopy and imaged by swept-source OCT (Casia OCT, Tomey, Nagoya, Japan) in room light and in the dark using the "angle analysis" protocol, which was composed of 128 radial B-scans each with 512 A-scans (16-mm scan length). The area and degree of PAS involvement were measured in each eye after manual detection of the scleral spur and the anterior irido-angle adhesion by 2 masked observers. The interobserver variability of the PAS measurements was calculated. The agreement of PAS assessment by gonioscopy and OCT, the area and the degree of PAS involvement, and the intraclass correlation coefficient (ICC) of interobserver PAS measurements. The area of PAS (mean ± standard deviation) was 20.8 ± 16.9 mm(2) (range, 3.9-74.9 mm(2)), and the degree of PAS involvement was 186.5 ± 79.9 degrees (range, 42-314 degrees). There was no difference in the area of PAS (P = 0.90) and the degree of PAS involvement (P = 0.95) between images obtained in room light and in the dark. The interobserver ICCs were 0.99 (95% confidence interval [CI], 0.98-1.00) for the area of PAS and 0.99 (95% CI, 0.97-1.00) for the degree of PAS involvement. There was good agreement of PAS assessment between gonioscopy and OCT images (kappa = 0.79; 95% CI, 0.67-0.91). Swept-source OCT allows visualization and reproducible measurements of the area and degree of PAS involvement, providing a new paradigm for evaluation of PAS progression and risk assessment

  4. Evaluation of circumferential angle closure using iridotrabecular contact index after laser iridotomy by swept-source optical coherence tomography.

    Science.gov (United States)

    Cho, Hyun-Kyung; Ahn, Dongsub; Kee, Changwon

    2017-05-01

    To investigate the quantitative changes of circumferential angle closure after laser iridotomy (LI) using the iridotrabecular contact (ITC) index by Swept-Source optical coherence tomography (OCT). In this prospective observational study conducted in a hospital setting, 42 eyes of 36 patients (five males, 31 females) who underwent LI were included. The mean age was 65.00 ± 8.13 years old and the diagnosis included primary angle closure (PAC, 21 eyes), PAC suspect (16 eyes) and PAC glaucoma (five eyes). Optical coherence tomography (OCT) images were obtained pre-LI and at 1 week post-LI. In each image frame, the scleral spur (SS) and the ITC end-point were marked, from which the ITC index was calculated as a percentage of the angle closure across 360°. Measurements inspected before and after LI included: central anterior chamber depth (ACD), anterior chamber volume (ACV), lens vault (LV), nasal and temporal angle opening distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), trabecular-iris angle (TIA) at 500 μm and 750 μm from the SS and intraocular pressure (IOP). The ITC index and IOP decreased significantly after LI from 71.52 ± 26.29 to 35.31 ± 27.19 and from 20.64 ± 12.72 mmHg to 14.02 ± 3.49 mmHg, respectively (p  0.05), but ACV increased significantly after LI (p angle parameters except for nasal TIAs increased significantly after LI (all p angle showed a significant decrease after LI, but part of the angle closure was not relieved after LI. Other mechanisms besides pupillary block may play a role together in causing angle closure. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  5. Applied optics

    International Nuclear Information System (INIS)

    Orszag, A.; Antonetti, A.

    1988-01-01

    The 1988 progress report, of the Applied Optics laboratory, of the (Polytechnic School, France), is presented. The optical fiber activities are focused on the development of an optical gyrometer, containing a resonance cavity. The following domains are included, in the research program: the infrared laser physics, the laser sources, the semiconductor physics, the multiple-photon ionization and the nonlinear optics. Investigations on the biomedical, the biological and biophysical domains are carried out. The published papers and the congress communications are listed [fr

  6. Clinical Factors Associated with Lamina Cribrosa Thickness in Patients with Glaucoma, as Measured with Swept Source Optical Coherence Tomography.

    Directory of Open Access Journals (Sweden)

    Kazuko Omodaka

    Full Text Available To investigate the influence of various risk factors on thinning of the lamina cribrosa (LC, as measured with swept-source optical coherence tomography (SS-OCT; Topcon.This retrospective study comprised 150 eyes of 150 patients: 22 normal subjects, 28 preperimetric glaucoma (PPG patients, and 100 open-angle glaucoma patients. Average LC thickness was determined in a 3 x 3 mm cube scan of the optic disc, over which a 4 x 4 grid of 16 points was superimposed (interpoint distance: 175 μm, centered on the circular Bruch's membrane opening. The borders of the LC were defined as the visible limits of the LC pores. The correlation of LC thickness with Humphrey field analyzer-measured mean deviation (MD; SITA standard 24-2, circumpapillary retinal nerve fiber layer thickness (cpRNFLT, the vertical cup-to-disc (C/D ratio, and tissue mean blur rate (MBR was determined with Spearman's rank correlation coefficient. The relationship of LC thickness with age, axial length, intraocular pressure (IOP, MD, the vertical C/D ratio, central corneal thickness (CCT, and tissue MBR was determined with multiple regression analysis. Average LC thickness and the correlation between LC thickness and MD were compared in patients with the glaucomatous enlargement (GE optic disc type and those with non-GE disc types, as classified with Nicolela's method.We found that average LC thickness in the 16 grid points was significantly associated with overall LC thickness (r = 0.77, P < 0.001. The measurement time for this area was 12.4 ± 2.4 minutes. Average LC thickness in this area had a correlation coefficient of 0.57 with cpRNFLT (P < 0.001 and 0.46 (P < 0.001 with MD. Average LC thickness differed significantly between the groups (normal: 268 ± 23 μm, PPG: 248 ± 13 μm, OAG: 233 ± 20 μm. Multiple regression analysis showed that MD (β = 0.29, P = 0.013, vertical C/D ratio (β = -0.25, P = 0.020 and tissue MBR (β = 0.20, P = 0.034 were independent variables significantly

  7. Silver nanoparticles (AgNPs) as a contrast agent for imaging of animal tissue using swept-source optical coherence tomography (SSOCT)

    Science.gov (United States)

    Mondal, Indranil; Raj, Shipra; Roy, Poulomi; Poddar, Raju

    2018-01-01

    We present noninvasive three-dimensional depth-resolved imaging of animal tissue with a swept-source optical coherence tomography system at 1064 nm center wavelength and silver nanoparticles (AgNPs) as a potential contrast agent. A swept-source laser light source is used to enable an imaging rate of 100 kHz (100 000 A-scans s-1). Swept-source optical coherence tomography is a new variant of the optical coherence tomography (OCT) technique, offering unique advantages in terms of sensitivity, reduction of motion artifacts, etc. To enhance the contrast of an OCT image, AgNPs are utilized as an exogeneous contrast agent. AgNPs are synthesized using a modified Tollens method and characterization is done by UV-vis spectroscopy, dynamic light scattering, scanning electron microscopy and energy dispersive x-ray spectroscopy. In vitro imaging of chicken breast tissue, with and without the application of AgNPs, is performed. The effect of AgNPs is studied with different exposure times. A mathematical model is also built to calculate changes in the local scattering coefficient of tissue from OCT images. A quantitative estimation of scattering coefficient and contrast is performed for tissues with and without application of AgNPs. Significant improvement in contrast and increase in scattering coefficient with time is observed.

  8. TOWARD IDENTIFYING THE UNASSOCIATED GAMMA-RAY SOURCE 1FGL J1311.7-3429 WITH X-RAY AND OPTICAL OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, J.; Takahashi, Y.; Maeda, K. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Yatsu, Y.; Kawai, N. [Tokyo Institute of Technology, 2-12-1, Ohokayama, Meguro, Tokyo 152-8551 (Japan); Urata, Y.; Tsai, A. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Cheung, C. C. [National Research Council Research Associate, National Academy of Sciences, Washington, DC 20001 (United States); Totani, T.; Makiya, R. [Department of Astronomy, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Hanayama, H.; Miyaji, T., E-mail: kataoka.jun@waseda.jp [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, 1024-1 Arakawa, Ishigaki, Okinawa, 907-0024 (Japan)

    2012-10-01

    We present deep optical and X-ray follow-up observations of the bright unassociated Fermi-LAT gamma-ray source 1FGL J1311.7-3429. The source was already known as an unidentified EGRET source (3EG J1314-3431, EGR J1314-3417), hence its nature has remained uncertain for the past two decades. For the putative counterpart, we detected a quasi-sinusoidal optical modulation of {Delta}m {approx} 2 mag with a period of {approx_equal}1.5 hr in the Rc, r', and g' bands. Moreover, we found that the amplitude of the modulation and peak intensity changed by {approx}>1 mag and {approx}0.5 mag, respectively, over our total six nights of observations from 2012 March to May. Combined with Swift UVOT data, the optical-UV spectrum is consistent with a blackbody temperature, kT {approx_equal} 1 eV and the emission volume radius R{sub bb} {approx_equal} 1.5 Multiplication-Sign 10{sup 4} d{sub kpc} km (d{sub kpc} is the distance to the source in units of 1 kpc). In contrast, deep Suzaku observations conducted in 2009 and 2011 revealed strong X-ray flares with a light curve characterized with a power spectrum density of P(f) {proportional_to} f {sup -2.0{+-}0.4}, but the folded X-ray light curves suggest an orbital modulation also in X-rays. Together with the non-detection of a radio counterpart, and significant curved spectrum and non-detection of variability in gamma-rays, the source may be the second 'radio-quiet' gamma-ray emitting millisecond pulsar candidate after 1FGL J2339.7-0531, although the origin of flaring X-ray and optical variability remains an open question.

  9. Active-Source Seismic Tomography at Bradys Geothermal Field, Nevada, with Dense Nodal and Fiber-Optic Seismic Arrays

    Science.gov (United States)

    Thurber, C. H.; Parker, L.; Li, P.; Fratta, D.; Zeng, X.; Feigl, K. L.; Ak, E.; Lord, N.

    2017-12-01

    We deployed a dense seismic array to image the shallow structure in the injection area of the Brady Hot Springs geothermal site in Nevada. The array was composed of 238 5 Hz, three-component nodal instruments and 8,700 m of distributed acoustic sensing (DAS) fiber-optic cable installed in surface trenches plus about 400 m installed in a borehole. The geophone array had about 60 m instrument spacing in the target zone, whereas DAS channel separations were about 1 m. The acquisition systems provided 15 days of continuous records including active source and ambient noise signals. A large vibroseis truck (T-Rex) was operated at 196 locations, exciting a swept-frequency signal from 5 to 80 Hz over 20 seconds using three vibration modes. Sweeps were repeated up to four times during different modes of geothermal plant operation: normal operation, shut-down, high and oscillatory injection and production, and normal operation again. The cross-correlation method was utilized to remove the sweep signal from the geophone records. The first P arrivals were automatically picked from the cross-correlation functions using a combination of methods, and the travel times were used to invert for the 3D P-wave velocity structure. Models with 100 m and 50 m horizontal node spacing were obtained, with vertical node spacing of 10 to 50 m. The travel time data were fit to about 30 ms, close to our estimated picking uncertainty. We will present our 3D Vp model and the result of our search for measurable temporal changes, along with preliminary results for a 3D Vs model. The work presented herein was funded in part by the Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy, under Award Number DE-EE0006760.

  10. In vivo crystalline lens measurements with novel swept-source optical coherent tomography: an investigation on variability of measurement

    Science.gov (United States)

    Shoji, Takuhei; Kato, Naoko; Ishikawa, Sho; Ibuki, Hisashi; Yamada, Norihiro; Kimura, Itaru; Shinoda, Kei

    2017-01-01

    Objective To evaluate the reproducibility of in vivo crystalline lens measurements obtained by novel commercially available swept-source (SS) optical coherence tomography (OCT) specifically designed for anterior segment imaging. Methods and analysis One eye from each of 30 healthy subjects was randomly selected using the CASIA2 (Tomey, Nagoya, Japan) in two separate visits within a week. Each eye was imaged twice. After image scanning, the anterior and posterior lens curvatures and lens thickness were calculated automatically by the CASIA2 built-in program at 0 dioptre (D) (static), −1 D, −3 D and −5 D accommodative stress. The intraobserver and intervisit reproducibility coefficient (RC) and intraclass correlation coefficient (ICC) were calculated. Results The intraobserver and intervisit RCs ranged from 0.824 to 1.254 mm and 0.789 to 0.911 mm for anterior lens curvature, from 0.276 to 0.299 mm and 0.221 to 0.270 mm for posterior lens curvature and from 0.065 to 0.094 mm and 0.054 to 0.132 mm for lens thickness, respectively. The intraobserver and intervisit ICCs ranged from 0.831 to 0.865 and 0.828 to 0.914 for anterior lens curvature, from 0.832 to 0.898 and 0.840 to 0.933 for posterior lens curvature and from 0.980 to 0.992 and 0.942 to 0.995 for lens thickness. High ICC values were observed for each measurement regardless of accommodative stress. RCs in younger subjects tended to be larger than those in older subjects. Conclusions This novel anterior segment SS-OCT instrument produced reliable in vivo crystalline lens measurement with good repeatability and reproducibility regardless of accommodation stress. PMID:29354706

  11. Can Probability Maps of Swept-Source Optical Coherence Tomography Predict Visual Field Changes in Preperimetric Glaucoma?

    Science.gov (United States)

    Lee, Won June; Kim, Young Kook; Jeoung, Jin Wook; Park, Ki Ho

    2017-12-01

    To determine the usefulness of swept-source optical coherence tomography (SS-OCT) probability maps in detecting locations with significant reduction in visual field (VF) sensitivity or predicting future VF changes, in patients with classically defined preperimetric glaucoma (PPG). Of 43 PPG patients, 43 eyes were followed-up on every 6 months for at least 2 years were analyzed in this longitudinal study. The patients underwent wide-field SS-OCT scanning and standard automated perimetry (SAP) at the time of enrollment. With this wide-scan protocol, probability maps originating from the corresponding thickness map and overlapped with SAP VF test points could be generated. We evaluated the vulnerable VF points with SS-OCT probability maps as well as the prevalence of locations with significant VF reduction or subsequent VF changes observed in the corresponding damaged areas of the probability maps. The vulnerable VF points were shown in superior and inferior arcuate patterns near the central fixation. In 19 of 43 PPG eyes (44.2%), significant reduction in baseline VF was detected within the areas of structural change on the SS-OCT probability maps. In 16 of 43 PPG eyes (37.2%), subsequent VF changes within the areas of SS-OCT probability map change were observed over the course of the follow-up. Structural changes on SS-OCT probability maps could detect or predict VF changes using SAP, in a considerable number of PPG eyes. Careful comparison of probability maps with SAP results could be useful in diagnosing and monitoring PPG patients in the clinical setting.

  12. Comparison of Keratometry Obtained by a Swept Source OCT-Based Biometer with a Standard Optical Biometer and Scheimpflug Imaging.

    Science.gov (United States)

    Asena, Leyla; Akman, Ahmet; Güngör, Sirel Gür; Dursun Altınörs, Dilek

    2018-04-09

    To assess agreement of a swept source-optical coherence tomography (SS-OCT) based Biometer with a standard IOLMaster device and Scheimpflug Imaging (SI) to acquire keratometric measurements in cataract patients. In this prospective comparative study, 101 eyes of 101 cataract surgery candidates, aged 24-81 years, were sequentially examined using three devices. Keratometry values at the flat (K1) and steep (K2) axis, mean corneal power (Km) and magnitude of corneal astigmatism as well as J0 and J45 vectoral components of astigmatism obtained with the SS-OCT based biometer (IOLMaster 700) were compared with those obtained with the IOLMaster 500 and SI. The agreement between measurements was evaluated by the Bland-Altman method, intraclass correlation coefficients (ICCs) and repeated-measures analysis of variance. Mean K1 values from the three devices were similar (p = 0.09). Mean K2 and Km values of IOLMaster 700 were higher than SI and lower than IOLMaster 500 (p = 0.04 for K2 and p = 0.02 for Km). There was a strong correlation between K1, K2, Km and magnitude of astigmatism obtained with all devices (r ≥ 0.80 and p devices was excellent for keratometric measurements. Mean K2, Km and astigmatism measurements from IOLMaster 700 were lower than IOLMaster 500 and higher than SI. However, the differences were quite small and are not expected to affect the final IOL power.

  13. Combination of highly nonlinear fiber, an optical bandpass filter, and a Fabry-Perot filter to improve the signal-to-noise ratio of a supercontinuum continuous-wave optical source.

    Science.gov (United States)

    Nan, Yinbo; Huo, Li; Lou, Caiyun

    2005-05-20

    We present a theoretical study of a supercontinuum (SC) continuous-wave (cw) optical source generation in highly nonlinear fiber and its noise properties through numerical simulations based on the nonlinear Schrödinger equation. Fluctuations of pump pulses generate substructures between the longitudinal modes that result in the generation of white noise and then in degradation of coherence and in a decrease of the modulation depths and the signal-to-noise ratio (SNR). A scheme for improvement of the SNR of a multiwavelength cw optical source based on a SC by use of the combination of a highly nonlinear fiber (HNLF), an optical bandpass filter, and a Fabry-Perot (FP) filter is presented. Numerical simulations show that the improvement in modulation depth is relative to the HNLF's length, the 3-dB bandwidth of the optical bandpass filter, and the reflection ratio of the FP filter and that the average improvement in modulation depth is 13.7 dB under specified conditions.

  14. Detection of volatile and soluble general anesthetics using a fluorescence-based fiber optic sensor: recent progress in chemical sensitivity and noise sources

    Science.gov (United States)

    Yager, Paul; Abrams, Susan B.

    1992-04-01

    A fiber optic sensor for general anesthetics based on the phase transition of immobilized phospholipid vesicles is under development. Current work centers on evaluating the sensor response to different anesthetics and instrumentation design. The fluorescence of laurdan- doped liposomes is found to respond linearly to the infusible anesthetics thiopental sodium and Propofol. Preliminary experiments have been performed to determine sources of noise in the optical and electronic components of the sensor as it is now configured. One potential noise source is the liposome sample at the fiber tip; photobleaching and thermal fluctuations due to heating by the illuminating 360 nm radiation can affect measurement of the anesthetic level. Heating of the sample is a factor at high illumination levels, but photobleaching, which reduces the signal intensity, does not alter the intensity ratio upon which the anesthetic concentration measurement is based. Optical microscopy of fiber tips embedded in liposomes allows direct observation of the light intensity near the tip of the fiber despite the extreme turbidity of the suspension. Light intensity drops to less than 10% of its maximum intensity at the fiber tip within 300 micrometers . Further use of this technique should allow monitoring the effects of photobleaching on the spatial distribution of the liposomes responsible for the measured optical signal.

  15. Mid infra-red hyper-spectral imaging with bright super continuum source and fast acousto-optic tuneable filter for cytological applications

    International Nuclear Information System (INIS)

    Farries, Mark; Ward, Jon; Valle, Stefano; Stephens, Gary; Moselund, Peter; Van der Zanden, Koen; Napier, Bruce

    2015-01-01

    Mid-IR imaging spectroscopy has the potential to offer an effective tool for early cancer diagnosis. Current development of bright super-continuum sources, narrow band acousto-optic tunable filters and fast cameras have made feasible a system that can be used for fast diagnosis of cancer in vivo at point of care. The performance of a proto system that has been developed under the Minerva project is described. (paper)

  16. Holographic Optical Element-Based Laser Diode Source System for Direct Metal Deposition in Space, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — To meet the challenges of rapid prototyping, direct hardware fabrication, and on-the-spot repairs on the ground and on NASA space platforms, Physical Optics...

  17. Sub-mm Scale Fiber Guided Deep/Vacuum Ultra-Violet Optical Source for Trapped Mercury Ion Clocks

    Science.gov (United States)

    Yi, Lin; Burt, Eric A.; Huang, Shouhua; Tjoelker, Robert L.

    2013-01-01

    We demonstrate the functionality of a mercury capillary lamp with a diameter in the sub-mm range and deep ultraviolet (DUV)/ vacuum ultraviolet (VUV) radiation delivery via an optical fiber integrated with the capillary. DUV spectrum control is observed by varying the fabrication parameters such as buffer gas type and pressure, capillary diameter, electrical resonator design, and temperature. We also show spectroscopic data of the 199Hg+ hyper-fine transition at 40.5GHz when applying the above fiber optical design. We present efforts toward micro-plasma generation in hollow-core photonic crystal fiber with related optical design and theoretical estimations. This new approach towards a more practical DUV optical interface could benefit trapped ion clock developments for future ultra-stable frequency reference and time-keeping applications.

  18. Assessment of circumferential angle-closure by the iris-trabecular contact index with swept-source optical coherence tomography.

    Science.gov (United States)

    Baskaran, Mani; Ho, Sue-Wei; Tun, Tin A; How, Alicia C; Perera, Shamira A; Friedman, David S; Aung, Tin

    2013-11-01

    To evaluate the diagnostic performance of the iris-trabecular contact (ITC) index, a measure of the degree of angle-closure, using swept-source optical coherence tomography (SSOCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan) in comparison with gonioscopy. Prospective observational study. A total of 108 normal subjects and 32 subjects with angle-closure. The SSOCT 3-dimensional angle scans, which obtain radial scans for the entire circumference of the angle, were performed under dark conditions and analyzed using customized software by a single examiner masked to the subjects' clinical details. The ITC index was calculated as a percentage of the angle that was closed on SSOCT images. First-order agreement coefficient (AC1) statistics and area under the receiver operating characteristic curve (AUC) analyses were performed for angle-closure on the basis of the ITC index in comparison with gonioscopy. Angle-closure on gonioscopy was defined as nonvisibility of posterior trabecular meshwork for at least 2 quadrants. Agreement of the ITC index with gonioscopically defined angle-closure was assessed using the AC1 statistic. Study subjects were predominantly Chinese (95.7%) and female (70.7%), with a mean age of 59.2 (standard deviation, 8.9) years. The median ITC index was 15.24% for gonioscopically open-angle eyes (n = 108) and 48.5% for closed-angle eyes (n = 32) (P = 0.0001). The agreement for angle-closure based on ITC index cutoffs (>35% and ≥50%) and gonioscopic angle-closure was 0.699 and 0.718, respectively. The AUC for angle-closure detection using the ITC index was 0.83 (95% confidence interval, 0.76-0.89), with an ITC index >35% having a sensitivity of 71.9% and specificity of 84.3%. The ITC index is a summary measure of the circumferential extent of angle-closure as imaged with SSOCT. The index had moderate agreement and good diagnostic performance for angle-closure with gonioscopy as the reference standard. Copyright © 2013 American Academy of

  19. Repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography macular metrics in healthy subjects.

    Science.gov (United States)

    Fang, Danqi; Tang, Fang Yao; Huang, Haifan; Cheung, Carol Y; Chen, Haoyu

    2018-05-29

    To investigate the repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography (SS-OCTA) metrics in healthy subjects. Thirty-three healthy normal subjects were enrolled. The macula was scanned four times by an SS-OCTA system using the 3 mm×3 mm mode. The superficial capillary map images were analysed using a MATLAB program. A series of parameters were measured: foveal avascular zone (FAZ) area, FAZ perimeter, FAZ circularity, parafoveal vessel density, fractal dimension and vessel diameter index (VDI). The repeatability of four scans was determined by intraclass correlation coefficient (ICC). Then the averaged results were analysed for intereye difference, correlation and agreement using paired t-test, Pearson's correlation coefficient (r), ICC and Bland-Altman plot. The repeatability assessment of the macular metrics exported high ICC values (ranged from 0.853 to 0.996). There is no statistically significant difference in the OCTA metrics between the two eyes. FAZ area (ICC=0.961, r=0.929) and FAZ perimeter (ICC=0.884, r=0.802) showed excellent binocular correlation. Fractal dimension (ICC=0.732, r=0.578) and VDI (ICC=0.707, r=0.547) showed moderate binocular correlation, while parafoveal vessel density had poor binocular correlation. Bland-Altman plots showed the range of agreement was from -0.0763 to 0.0954 mm 2 for FAZ area and from -0.0491 to 0.1136 for parafoveal vessel density. The macular metrics obtained using SS-OCTA showed excellent repeatability in healthy subjects. We showed high intereye correlation in FAZ area and perimeter, moderate correlation in fractal dimension and VDI, while vessel density had poor correlation in normal healthy subjects. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over northwestern China

    Science.gov (United States)

    Wang, Xin; Wen, Hui; Shi, Jinsen; Bi, Jianrong; Huang, Zhongwei; Zhang, Beidou; Zhou, Tian; Fu, Kaiqi; Chen, Quanliang; Xin, Jinyuan

    2018-02-01

    Mineral dust aerosols (MDs) not only influence the climate by scattering and absorbing solar radiation but also modify cloud properties and change the ecosystem. From 3 April to 16 May 2014, a ground-based mobile laboratory was deployed to measure the optical and microphysical properties of MDs near dust source regions in Wuwei, Zhangye, and Dunhuang (in chronological order) along the Hexi Corridor over northwestern China. Throughout this dust campaign, the hourly averaged (±standard deviation) aerosol scattering coefficients (σsp, 550 nm) of the particulates with aerodynamic diameters less than 2.5 µm (PM2.5) at these three sites were sequentially 101.5 ± 36.8, 182.2 ± 433.1, and 54.0 ± 32.0 Mm-1. Correspondingly, the absorption coefficients (σap, 637 nm) were 9.7 ± 6.1, 6.0 ± 4.6, and 2.3 ± 0.9 Mm-1; single-scattering albedos (ω, 637 nm) were 0.902 ± 0.025, 0.931 ± 0.037, and 0.949 ± 0.020; and scattering Ångström exponents (Åsp, 450-700 nm) of PM2.5 were 1.28 ± 0.27, 0.77 ± 0.51, and 0.52 ± 0.31. During a severe dust storm in Zhangye (i.e., from 23 to 25 April), the highest values of σsp2.5 ( ˜ 5074 Mm-1), backscattering coefficient (σbsp2.5, ˜ 522 Mm-1), and ω637 ( ˜ 0.993) and the lowest values of backscattering fraction (b2.5, ˜ 0.101) at 550 nm and Åsp2.5 ( ˜ -0.046) at 450-700 nm, with peak values of aerosol number size distribution (appearing at the particle diameter range of 1-3 µm), exhibited that the atmospheric aerosols were dominated by coarse-mode dust aerosols. It is hypothesized that the relatively higher values of mass scattering efficiency during floating dust episodes in Wuwei and Zhangye are attributed to the anthropogenic soil dust produced by agricultural cultivations.

  1. A high-energy, high-flux source of gamma-rays from all-optical non-linear Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Corvan, D.J., E-mail: dcorvan01@qub.ac.uk; Zepf, M.; Sarri, G.

    2016-09-01

    γ-Ray sources are among the most fundamental experimental tools currently available to modern physics. As well as the obvious benefits to fundamental research, an ultra-bright source of γ-rays could form the foundation of scanning of shipping containers for special nuclear materials and provide the bases for new types of cancer therapy. However, for these applications to prove viable, γ-ray sources must become compact and relatively cheap to manufacture. In recent years, advances in laser technology have formed the cornerstone of optical sources of high energy electrons which already have been used to generate synchrotron radiation on a compact scale. Exploiting the scattering induced by a second laser, one can further enhance the energy and number of photons produced provided the problems of synchronisation and compact γ-ray detection are solved. Here, we report on the work that has been done in developing an all-optical and hence, compact non-linear Thomson scattering source, including the new methods of synchronisation and compact γ-ray detection. We present evidence of the generation of multi-MeV (maximum 16–18 MeV) and ultra-high brilliance (exceeding 10{sup 20} photons s{sup −1}mm{sup −2}mrad{sup −2} 0.1% BW at 15 MeV) γ-ray beams. These characteristics are appealing for the paramount practical applications mentioned above. - Highlights: • How synchrotron radiation can be produced in an all optical setting using laser-plasmas. • Generating high-energy, high-flux gamma ray beams. • Presenting results from a recent NLTS experimental campaign. • Reveal insight into the experimental techniques employed.

  2. Tests of a polarized source of hydrogen and deuterium based on spin-exchange optical pumping and a storage cell for polarized deuterium

    International Nuclear Information System (INIS)

    Holt, R.J.; Gilman, R.; Kinney, E.R.

    1988-01-01

    A novel laser-driven polarized source of hydrogen and deuterium which is based on the principle of spin-exchange optical pumping has been developed at Argonne. The advantages of this method over conventional polarized sources for internal target experiments is discussed. At present, the laser-driven polarized source delivers hydrogen 8 x 10 16 atoms/s with a polarization of 24% and deuterium at 6 x 10 16 atoms/s with a polarization of 25%. A passive storage cell for polarized deuterium was tested in the VEPP-3 electron storage ring. The storage cell was found to increase the target thickness by approximately a factor of three and no loss in polarization was observed. 10 refs., 4 figs., 2 tabs

  3. 13.1 micrometers hard X-ray focusing by a new type monocapillary X-ray optic designed for common laboratory X-ray source

    Science.gov (United States)

    Sun, Xuepeng; zhang, Xiaoyun; Zhu, Yu; Wang, Yabing; Shang, Hongzhong; Zhang, Fengshou; Liu, Zhiguo; Sun, Tianxi

    2018-04-01

    A new type of monocapillary X-ray optic, called 'two bounces monocapillary X-ray optics' (TBMXO), is proposed for generating a small focal spot with high power-density gain for micro X-ray analysis, using a common laboratory X-ray source. TBMXO is consists of two parts: an ellipsoidal part and a tapered part. Before experimental testing, the TBMXO was simulated by the ray tracing method in MATLAB. The simulated results predicted that the proposed TBMXO would produce a smaller focal spot with higher power-density gain than the ellipsoidal monocapillary X-ray optic (EMXO). In the experiment, the TBMXO performance was tested by both an optical device and a Cu target X-ray tube with focal spot of 100 μm. The results indicated that the TBMXO had a slope error of 57.6 μrad and a 13.1 μm focal spot and a 1360 gain in power density were obtained.

  4. Research and development on optically pumped polarized ion sources. Technical progress report, July 1, 1985-June 30, 1986

    International Nuclear Information System (INIS)

    Anderson, L.W.

    1986-07-01

    The development of an optically pumped polarized 23 Na target is discussed. The three categories of research are: (1) electron spin relaxation of the 23 Na due to wall collisions; (2) effects of radiation trapping on the polarization that can be produced in an alkali target by optical pumping; and (3) the effects of spin exchange collisions in the polarization of a fast H 0 beam formed by charge transfer as an H + beam passes through a polarized alkali target. 90 refs., 7 figs

  5. Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over northwestern China

    Directory of Open Access Journals (Sweden)

    X. Wang

    2018-02-01

    Full Text Available Mineral dust aerosols (MDs not only influence the climate by scattering and absorbing solar radiation but also modify cloud properties and change the ecosystem. From 3 April to 16 May 2014, a ground-based mobile laboratory was deployed to measure the optical and microphysical properties of MDs near dust source regions in Wuwei, Zhangye, and Dunhuang (in chronological order along the Hexi Corridor over northwestern China. Throughout this dust campaign, the hourly averaged (±standard deviation aerosol scattering coefficients (σsp, 550 nm of the particulates with aerodynamic diameters less than 2.5 µm (PM2.5 at these three sites were sequentially 101.5 ± 36.8, 182.2 ± 433.1, and 54.0 ± 32.0 Mm−1. Correspondingly, the absorption coefficients (σap, 637 nm were 9.7 ± 6.1, 6.0 ± 4.6, and 2.3 ± 0.9 Mm−1; single-scattering albedos (ω, 637 nm were 0.902 ± 0.025, 0.931 ± 0.037, and 0.949 ± 0.020; and scattering Ångström exponents (Åsp, 450–700 nm of PM2.5 were 1.28 ± 0.27, 0.77 ± 0.51, and 0.52 ± 0.31. During a severe dust storm in Zhangye (i.e., from 23 to 25 April, the highest values of σsp2.5 ( ∼  5074 Mm−1, backscattering coefficient (σbsp2.5,  ∼  522 Mm−1, and ω637 ( ∼  0.993 and the lowest values of backscattering fraction (b2.5,  ∼  0.101 at 550 nm and Åsp2.5 ( ∼  −0.046 at 450–700 nm, with peak values of aerosol number size distribution (appearing at the particle diameter range of 1–3 µm, exhibited that the atmospheric aerosols were dominated by coarse-mode dust aerosols. It is hypothesized that the relatively higher values of mass scattering efficiency during floating dust episodes in Wuwei and Zhangye are attributed to the anthropogenic soil dust produced by agricultural cultivations.

  6. Dual-channel operation in a synchronously pumped optical parametric oscillator for the generation of broadband mid-infrared coherent light sources.

    Science.gov (United States)

    Liu, Pei; Wang, Sicong; He, Puyuan; Zhang, Zhaowei

    2018-05-01

    We report, to the best of our knowledge, a novel approach for generating broadband mid-infrared (mid-IR) light by implementing a dual-channel scheme in a synchronously pumped optical parametric oscillator (SPOPO). Two-channel operation was achieved by inserting a prism pair and two reflection mirrors inside an optical parametric oscillator (OPO) cavity. Pumped by a Yb-fiber laser, the OPO generated an idler wave at ∼3150  nm with a -10  dB bandwidth of ∼13.2  THz, which was twice as much as that of the pump source. This scheme represents a promising technical route to transform conventional SPOPOs into a device capable of generating mid-IR light with very broad instantaneous bandwidth.

  7. Monitoring of "all-weather" evapotranspiration using optical and passive microwave remote sensing imagery over the River Source Region in Southwest China

    Science.gov (United States)

    Ma, Y.; Liu, S.

    2017-12-01

    Accurate estimation of surface evapotranspiration (ET) with high quality is one of the biggest obstacles for routine applications of remote sensing in eco-hydrological studies and water resource management at basin scale. However, many aspects urgently need to deeply research, such as the applicability of the ET models, the parameterization schemes optimization at the regional scale, the temporal upscaling, the selecting and developing of the spatiotemporal data fusion method and ground-based validation over heterogeneous land surfaces. This project is based on the theoretically robust surface energy balance system (SEBS) model, which the model mechanism need further investigation, including the applicability and the influencing factors, such as local environment, and heterogeneity of the landscape, for improving estimation accuracy. Due to technical and budget limitations, so far, optical remote sensing data is missing due to frequent cloud contamination and other poor atmospheric conditions in Southwest China. Here, a multi-source remote sensing data fusion method (ESTARFM: Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model) method will be proposed through blending multi-source remote sensing data acquired by optical, and passive microwave remote sensors on board polar satellite platforms. The accurate "all-weather" ET estimation will be carried out for daily ET of the River Source Region in Southwest China, and then the remotely sensed ET results are overlapped with the footprint-weighted images of EC (eddy correlation) for ground-based validation.

  8. Design rules for a compact and low-cost optical position sensing of MOEMS tilt mirrors based on a Gaussian-shaped light source

    Science.gov (United States)

    Baumgart, Marcus; Tortschanoff, Andreas

    2013-05-01

    A tilt mirror's deflection angle tracking setup is examined from a theoretical point of view. The proposed setup is based on a simple optical approach and easily scalable. Thus, the principle is especially of interest for small and fast oscillating MEMS/MOEMS based tilt mirrors. An experimentally established optical scheme is used as a starting point for accurate and fast mirror angle-position detection. This approach uses an additional layer, positioned under the MOEMS mirror's backside, consisting of a light source in the center and two photodetectors positioned symmetrical around the center. The mirror's back surface is illuminated by the light source and the intensity change due to mirror tilting is tracked via the photodiodes. The challenge of this method is to get a linear relation between the measured intensity and the current mirror tilt angle even for larger angles. State-of-the-art MOEMS mirrors achieve angles up to ±30°, which exceeds the linear angle approximations. The use of an LED, small laser diode or VCSEL as a lightsource is appropriate due to their small size and inexpensive price. Those light sources typically emit light with a Gaussian intensity distribution. This makes an analytical prediction of the expected detector signal quite complicated. In this publication an analytical simulation model is developed to evaluate the influence of the main parameters for this optical mirror tilt-sensor design. An easy and fast to calculate value directly linked to the mirror's tilt-angle is the "relative differential intensity" (RDI = (I1 - I2) / (I1 + I2)). Evaluation of its slope and nonlinear error highlights dependencies between the identified parameters for best SNR and linearity. Also the energy amount covering the detector area is taken into account. Design optimizing rules are proposed and discussed based on theoretical considerations.

  9. An undulator based high flux and high resolution beamline for atomic, molecular and optical science (AMOS) research at INDUS-2 synchrotron radiation source (SRS)

    International Nuclear Information System (INIS)

    Das, Asim Kumar; Rajasekhar, B.N.; Sahoo, N.K.

    2014-08-01

    A dedicated UV-VUV and soft X-ray beamline to provide several new research opportunities in Photon induced processes in the energy range of 6-250 eV for Atomic Molecular and Optical Science (AMOS) research, a domain still less explored both at national as well international level, has been proposed by Atomic and Molecular Physics Division, BARC. This beamline will use a planar permanent magnet (PPM) undulator based on Indus-2 Synchrotron Radiation Source (SRS), a 2.5 GeV third generation electron storage ring at RRCAT, Indore, India and is expected to offer a variety of opportunities for more advanced and sustained investigations for AMOS research. A plane mirror and a toroidal mirror are used as the pre-focusing optics of the AMOS beamline. A varied line spacing plane grating monochromator (VLSPGM) in a converging beam, constant included angle mode containing one toroidal focusing mirror and four interchangeable gratings is to be used to cover the energy range of 6 to 250 eV and obtain resolving powers ∼10 4 and intensity ∼10 12 ph/s at the sample position. A toroidal mirror is used to focus the diverging monochromatic light from the monochromator at a distance of 150 cm with a 1:1 magnification. As the first step towards the beamline optics design, the evaluation of the PPM undulator radiation characteristics relevant to beamline design has been performed using the Indus-2 SRS parameters in the long straight section of the ring, PPM undulator parameters, and the empirical expressions available in literature. The software resources such as XOPS, ESRF, France and SPECTRA, Photon factory, Japan have been used for detailed modelling and verification of the empirical computations. Beamline layout preparation, optimization, imaging performance evaluation, and resolving power calculations for ideal beamline optics are carried out using SHADOWVUI, an extension of XOPS software resource. A new mounting of the optical components in the monochromator has been proposed

  10. Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

    Science.gov (United States)

    Quinn, P. K.; Coffman, D. J.; Bates, T. S.; Welton, E. J.; Covert, D. S.; Miller, T. L.; Johnson, J. E.; Maria, S.; Russell, L.; Arimoto, R.

    2004-01-01

    During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic

  11. Effect of the cadmium ion source on the structural and optical properties of chemical bath deposited CdS thin films

    Science.gov (United States)

    Rami, M.; Benamar, E.; Fahoume, M.; Chraibi, F.; Ennaoui, A.

    1999-06-01

    The chemical bath deposition (CBD) technique has been successfully used to deposit cadmium sulphide from cadmium chloride and cadmium acetate as the cadmium ion source and thiourea as the sulphur source on both glass microscope slide and indium tin oxide coated glass substrates. Various properties of the films such as surface morphology, crystallinity, optical properties and resistivitiy have been investigated. XRD patterns reveal that the CdS films deposited from cadmium chloride have an hexagonal structure. Their preferential orientation changes from (002) to (100) with the thermal annealing. Films deposited from cadmium acetate are amorphous but improve their crystallinity with annealing. SEM analysis shows that the grains of the as deposited films are randomly shaped and appear to be bigger in the case of the CdS prepared from cadmium chloride. The optical transmission of the layers are in the 70-80 % range for wavelength above the band gap absorption which makes them more appropriate as window material in heterojunction solar cells.

  12. Effect of the cadmium ion source on the structural and optical properties of chemical bath deposited CdS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rami, M.; Benamar, E.; Fahoume, M.; Chraibi, F.; Ennaoui, A. [University Mohamed V, Laboratory of Materials Physics, Dept., Faculty of Sciences, Rabat (Morocco)

    1999-06-01

    The chemical bath deposition (CBD) technique has been successfully used to deposit cadmium sulphide from cadmium chloride and cadmium acetate as the cadmium ion source and thiourea as the sulphur source on both glass microscope slide and indium tin oxide coated glass substrates. Various properties of the films such as surface morphology, crystallinity, optical properties and resistivity have been investigated. XRD patterns reveal that the CdS films deposited from cadmium chloride have an hexagonal structure. Their preferential orientation changes from (002) to (100) with the thermal annealing. Films deposited from cadmium acetate are amorphous but improve their crystallinity with annealing. SEM analysis shows that the grains of the as deposited films are randomly shaped and appear to be bigger in the case of the CdS prepared from cadmium chloride. The optical transmission of the layers are in the 70-80% range for wavelength above the band gap absorption which makes them more appropriate as window material in heterojunction solar cells. (authors)

  13. Ultraviolet/Optical Emission of the Ionized Gas in AGN: Diagnostics of the Ionizing Source and Gas Properties

    Directory of Open Access Journals (Sweden)

    Anna Feltre

    2017-11-01

    Full Text Available Spectroscopic studies of active galactic nuclei (AGN are powerful means of probing the physical properties of the ionized gas within them. In particular, near future observational facilities, such as the James Webb Space Telescope (JWST, will allow detailed statistical studies of rest-frame ultraviolet and optical spectral features of the very distant AGN with unprecedented accuracy. In this proceedings, we discuss the various ways of exploiting new dedicated photoionization models of the narrow-line emitting regions (NLR of AGN for the interpretation of forthcoming revolutionary datasets.

  14. Ultraviolet/Optical Emission of the Ionized Gas in AGN: Diagnostics of the Ionizing Source and Gas Properties

    Energy Technology Data Exchange (ETDEWEB)

    Feltre, Anna [Univ Lyon, Univ Lyon1, Ens de Lyon, Centre National de la Recherche Scientifique, Centre de Recherche Astrophysique de Lyon UMR5574, Saint-Genis-Laval (France); Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France); Charlot, Stephane [Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France); Mignoli, Marco [INAF-Osservatorio Astronomico di Bologna, Bologna (Italy); Bongiorno, Angela [INAF-Osservatorio Astronomico di Roma, Monteporzio Catone (Italy); Calura, Francesco [INAF-Osservatorio Astronomico di Bologna, Bologna (Italy); Chevallard, Jacopo [Scientific Support Office, Directorate of Science and Robotic Exploration, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk (Netherlands); Curtis-Lake, Emma [Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France); Gilli, Roberto [INAF-Osservatorio Astronomico di Bologna, Bologna (Italy); Plat, Adele, E-mail: anna.feltre@univ-lyon1.fr [Sorbonne Universités, UPMC-Centre National de la Recherche Scientifique, UMR7095, Institut d' Astrophysique de Paris, Paris (France)

    2017-11-02

    Spectroscopic studies of active galactic nuclei (AGN) are powerful means of probing the physical properties of the ionized gas within them. In particular, near future observational facilities, such as the James Webb Space Telescope (JWST), will allow detailed statistical studies of rest-frame ultraviolet and optical spectral features of the very distant AGN with unprecedented accuracy. In this proceedings, we discuss the various ways of exploiting new dedicated photoionization models of the narrow-line emitting regions (NLR) of AGN for the interpretation of forthcoming revolutionary datasets.

  15. Characterizing and locating air pollution sources in a complex industrial district using optical remote sensing technology and multivariate statistical modeling.

    Science.gov (United States)

    Chang, Pao-Erh Paul; Yang, Jen-Chih Rena; Den, Walter; Wu, Chang-Fu

    2014-09-01

    Emissions of volatile organic compounds (VOCs) are most frequent environmental nuisance complaints in urban areas, especially where industrial districts are nearby. Unfortunately, identifying the responsible emission sources of VOCs is essentially a difficult task. In this study, we proposed a dynamic approach to gradually confine the location of potential VOC emission sources in an industrial complex, by combining multi-path open-path Fourier transform infrared spectrometry (OP-FTIR) measurement and the statistical method of principal component analysis (PCA). Close-cell FTIR was further used to verify the VOC emission source by measuring emitted VOCs from selected exhaust stacks at factories in the confined areas. Multiple open-path monitoring lines were deployed during a 3-month monitoring campaign in a complex industrial district. The emission patterns were identified and locations of emissions were confined by the wind data collected simultaneously. N,N-Dimethyl formamide (DMF), 2-butanone, toluene, and ethyl acetate with mean concentrations of 80.0 ± 1.8, 34.5 ± 0.8, 103.7 ± 2.8, and 26.6 ± 0.7 ppbv, respectively, were identified as the major VOC mixture at all times of the day around the receptor site. As the toxic air pollutant, the concentrations of DMF in air samples were found exceeding the ambient standard despite the path-average effect of OP-FTIR upon concentration levels. The PCA data identified three major emission sources, including PU coating, chemical packaging, and lithographic printing industries. Applying instrumental measurement and statistical modeling, this study has established a systematic approach for locating emission sources. Statistical modeling (PCA) plays an important role in reducing dimensionality of a large measured dataset and identifying underlying emission sources. Instrumental measurement, however, helps verify the outcomes of the statistical modeling. The field study has demonstrated the feasibility of

  16. Field distributions and particle optics in main bending dipoles of Oak Ridge Spallation Neutron Source accumulator ring

    International Nuclear Information System (INIS)

    Wang, J.G.

    2013-01-01

    The SNS accumulator ring employs 32 electro-magnetic dipoles to bend proton beams. The dipoles are typical sector magnets with relatively large aperture and short length. Thus, how to correctly treat magnetic fringe fields in the devices remains as a question. We have performed 3D computer simulations to study magnetic field distributions in the dipoles. Further, we have analyzed particle optics based on the space-dependent curvature and focusing functions in the magnets. The effect of magnetic fringe fields on the particle motion, especially the focusing/defocusing and dispersion, is investigated. The lens parameters, including the second-order aberrations, are derived and compared with the design hard-edge parameters used in the ring lattice calculations

  17. Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy source

    Science.gov (United States)

    Armus, Lee; Heckman, Timothy M.; Miley, George K.

    1989-01-01

    Optical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.

  18. A beam optics study of a modular multi-source X-ray tube for novel computed tomography applications

    Science.gov (United States)

    Walker, Brandon J.; Radtke, Jeff; Chen, Guang-Hong; Eliceiri, Kevin W.; Mackie, Thomas R.

    2017-10-01

    A modular implementation of a scanning multi-source X-ray tube is designed for the increasing number of multi-source imaging applications in computed tomography (CT). An electron beam array coupled with an oscillating magnetic deflector is proposed as a means for producing an X-ray focal spot at any position along a line. The preliminary multi-source model includes three thermionic electron guns that are deflected in tandem by a slowly varying magnetic field and pulsed according to a scanning sequence that is dependent on the intended imaging application. Particle tracking simulations with particle dynamics analysis software demonstrate that three 100 keV electron beams are laterally swept a combined distance of 15 cm over a stationary target with an oscillating magnetic field of 102 G perpendicular to the beam axis. Beam modulation is accomplished using 25 μs pulse widths to a grid electrode with a reverse gate bias of -500 V and an extraction voltage of +1000 V. Projected focal spot diameters are approximately 1 mm for 138 mA electron beams and the stationary target stays within thermal limits for the 14 kW module. This concept could be used as a research platform for investigating high-speed stationary CT scanners, for lowering dose with virtual fan beam formation, for reducing scatter radiation in cone-beam CT, or for other industrial applications.

  19. Tunable, continuous-wave, ultraviolet source based on intracavity sum-frequency-generation in an optical parametric oscillator using BiB₃O₆.

    Science.gov (United States)

    Devi, Kavita; Kumar, S Chaitanya; Ebrahim-Zadeh, M

    2013-10-21

    We report a continuous-wave (cw) source of tunable radiation across 333-345 nm in the ultraviolet (UV) using bismuth triborate, BiB₃O₆ (BIBO) as the nonlinear gain material. The source is based on internal sum-frequency-generation (SFG) in a cw singly-resonant optical parametric oscillator (OPO) pumped at 532 nm. The compact tunable source employs a 30-mm-long MgO:sPPLT crystal as the OPO gain medium and a 5-mm-long BIBO crystal for intracavity SFG of the signal and pump, providing up to 21.6 mW of UV power at 339.7 nm, with >15 mW over 64% of the SFG tuning range. The cw OPO is also tunable across 1158-1312 nm in the idler, delivering as much as 1.7 W at 1247 nm, with >1W over 65% of the tuning range. The UV output at maximum power exhibits passive power stability better than 3.4% rms and frequency stability of 193 GHz over more than one minute.

  20. Synthesis, spectroscopic, structural and optical studies of Ru2S3 nanoparticles prepared from single-source molecular precursors

    Science.gov (United States)

    Mbese, Johannes Z.; Ajibade, Peter A.

    2017-09-01

    Homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared and characterized by spectroscopic techniques and thermogravimetric analyses. The thermogravimetric analyses (TGA) of the ruthenium complexes showed that the complexes decompose to ruthenium(III) sulfide nanoparticles. The ruthenium(III) complexes were dispersed in oleic acid and thermolysed in hexadecylamine to prepared oleic acid/hexadecylamine capped Ru2S3 nanoparticles. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the -NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. EDS spectra revealed that the prepared nanoparticles are mainly composed of Ru and S, confirming the formation of Ru2S3 nanoparticles. Powder XRD confirms that the nanoparticles are in cubic phase. The inner morphology of nanoparticles obtained from transmission electron microscopy (TEM) showed nanoparticles with narrow particle size distributions characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot are in the range 3.44-4.18 eV.

  1. Laser Cutting of CFRP with a Fibre Guided High Power Nanosecond Laser Source - Influence of the Optical Fibre Diameter on Quality and Efficiency

    Science.gov (United States)

    Bluemel, S.; Bastick, S.; Staehr, R.; Jaeschke, P.; Suttmann, O.; Overmeyer, L.

    For the development of a robot based laser cutting process of automotive 3D parts consisting of carbon fibre reinforced plastics (CFRP), investigations with a newly developed fibre guided nanosecond pulsed laser with an average power of PL = 1.5 kW were conducted. In order to investigate the best combination of quality and process time 2 different optical fibres were used, with diameters of df = 400 μm and df = 600 μm. The main differences between the two setups are the resulting focal diameter and the maximum available pulse energy up to EP = 80 mJ. In a first instance, a comparable investigation was performed with both fibres for a constant pulse overlap. For each fibre the minimum required line energy was investigated and cuts were performed, distributed over the complete parameter range of the laser source. The influences of the fibre diameter on the quality and efficiency of the cutting process are summarized and discussed.

  2. Atmospheric boundary layer CO2 remote sensing with a direct detection LIDAR instrument based on a widely tunable optical parametric source.

    Science.gov (United States)

    Cadiou, Erwan; Mammez, Dominique; Dherbecourt, Jean-Baptiste; Gorju, Guillaume; Pelon, Jacques; Melkonian, Jean-Michel; Godard, Antoine; Raybaut, Myriam

    2017-10-15

    We report on the capability of a direct detection differential absorption lidar (DIAL) for range resolved and integrated path (IPDIAL) remote sensing of CO 2 in the atmospheric boundary layer (ABL). The laser source is an amplified nested cavity optical parametric oscillator (NesCOPO) emitting approximately 8 mJ at the two measurement wavelengths selected near 2050 nm. Direct detection atmospheric measurements are taken from the ground using a 30 Hz frequency switching between emitted wavelengths. Results show that comparable precision measurements are achieved in DIAL and IPDIAL modes (not better than a few ppm) on high SNR targets such as near range ABL aerosol and clouds, respectively. Instrumental limitations are analyzed and degradation due to cloud scattering variability is discussed to explain observed DIAL and IPDIAL limitations.

  3. Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection.

    Science.gov (United States)

    Wang, Zhao; Lee, Hsiang-Chieh; Vermeulen, Diedrik; Chen, Long; Nielsen, Torben; Park, Seo Yeon; Ghaemi, Allan; Swanson, Eric; Doerr, Chris; Fujimoto, James

    2015-07-01

    Optical coherence tomography (OCT) is a widely used three-dimensional (3D) optical imaging method with many biomedical and non-medical applications. Miniaturization, cost reduction, and increased functionality of OCT systems will be critical for future emerging clinical applications. We present a silicon photonic integrated circuit swept-source OCT (SS-OCT) coherent receiver with dual polarization, dual balanced, in-phase and quadrature (IQ) detection. We demonstrate multiple functional capabilities of IQ polarization resolved detection including: complex-conjugate suppressed full-range OCT, polarization diversity detection, and polarization-sensitive OCT. To our knowledge, this is the first demonstration of a silicon photonic integrated receiver for OCT. The integrated coherent receiver provides a miniaturized, low-cost solution for SS-OCT, and is also a key step towards a fully integrated high speed SS-OCT system with good performance and multi-functional capabilities. With further performance improvement and cost reduction, photonic integrated technology promises to greatly increase penetration of OCT systems in existing applications and enable new applications.

  4. Optical memory

    Science.gov (United States)

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  5. Earth, soil and environmental science research facility at sector 13 of the Advanced Photon Source. I. Sector layout and optical design

    Energy Technology Data Exchange (ETDEWEB)

    Eng, P.; Jaski, Y.R.; Lazarz, N.; Murray, P.; Pluth, J.; Rarback, H.; Rivers, M.; Sutton, S. [CARS, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL (United States)

    1996-09-01

    The earth, soil and environmental science component (GSECARS) of the Consortium of Advanced Radiation Sources (CARS), is designing a national research facility to be built at sector 13 of the Advanced Photon Source. The bending magnet beam will be split to allow simultaneous operation of two stations, a monochromatic (8{endash}15 keV) side station and a multipurpose, white beam/monochromatic end station. The undulator beamline will have two white beam stations, which may operate simultaneously using a double-crystal monochromator (cryogenic Si) with a thin first crystal. In this mode, the upstream station will accept the monochromatized (4.5{endash}22 keV) beam deflected horizontally by a third (bendable) Ge crystal, while the end station accepts the high energy component (blue beam) transmitted by the first crystal. The need for small x-ray beams and broad spectral range have led us to base the focusing aspects of the optic design on grazing incidence mirrors. Both our bending magnet and insertion device beamlines will have long ({approximately}1 m), bendable mirrors (demagnification {lt}11, E(cut-off) {approx_gt}70 keV; beam sizes {approx_gt}tens of micrometers). For smaller focal spots, we will use small, dynamically bent Kirpatrick-Baez mirrors (demagnification 100{endash}400; E(cut-off) {lt}70 keV; beam sizes {approximately}1 micrometer). A unique aspect of our insertion device beamline is the ability to deliver focused white beam to the sample, through the incorporation of a power management pinhole in the first optics enclosure. {copyright} {ital 1996 American Institute of Physics.}

  6. Optics/Optical Diagnostics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Optics/Optical Diagnostics Laboratory supports graduate instruction in optics, optical and laser diagnostics and electro-optics. The optics laboratory provides...

  7. Facile preparation of PbS nanostructures and PbS/f-CNT nanocomposites using xanthate as sulfur source: Thermal and optical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Golabi, Parisa; Akbarzadeh, Raziyeh; Dehghani, Hossein, E-mail: dehghani@kashanu.ac.ir

    2015-10-25

    PbS nanostructures with different morphologies were fabricated using a new sulfur source through a facile and low cost hydro(solvo)thermal method. The influence of different reaction factors such as sulfur source, temperature, reactant, solvent and surfactant on the size and morphology of the obtained PbS particles were investigated. Beside, a simple hydrothermal process at low temperature (60 °C) for little time (4 h), has been used for preparation of PbS nanoparticles (NPs)/functionalized multi wall carbon nanotubes (f-MWCNTs) nanocomposite. The as-prepared nanocomposite possesses excellent thermal and optical properties. Thermal stability increases by depositing PbS nanoparticles on the surface of CNT. The structure, morphology, thermal and optical properties of the as-prepared nanocompounds were studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy, Thermogravimetric analysis (TGA), Pl spectra and UV–Vis absorption spectra. Photoluminescence spectra of PbS NPs and nanocomposite are consist of two emission peaks which centered at around 402 and 423 nm, when excited at 350 nm. It was noteworthy that the blue luminescence intensity over PbS/f-CNT nanocomposite is very lower than that of pure PbS NPs. Remarkable blue-shift from bulk material was observed on the PbS nanoparticles using UV–Vis spectrum. Furthermore, possible growth mechanism of PbS nanostructures is presented. - Graphical abstract: PbS nanostructures with different morphologies were fabricated using xanthate as sulfide source. Also, PbS/f-CNT nanocomposites were synthesized by simple hydrothermal process at low temperature (60 °C) for little time (4 h). - Highlights: • Sodium tert-butyl xanthate was used as sulfur source for synthesis of PbS. • Pb(CH{sub 3}COO){sub 2}·3H{sub 2}O salt was used for synthesis of PbS. • PbS/CNT nanocomposite was synthesized in deionized water for 4 h at 60

  8. Optical holography

    CERN Document Server

    Collier, Robert J; Lin, Lawrence H

    1971-01-01

    Optical Holography deals with the use of optical holography to solve technical problems, with emphasis on the properties of holograms formed with visible light. Topics covered include the Fourier transform, propagation and diffraction, pulsed-laser holography, and optical systems with spherical lenses. A geometric analysis of point-source holograms is also presented, and holograms and hologram spatial filters formed with spatially modulated reference waves are described. This book is comprised of 20 chapters and begins with an introduction to concepts that are basic to understanding hologr

  9. High-power LED light sources for optical measurement systems operated in continuous and overdriven pulsed modes

    Science.gov (United States)

    Stasicki, Bolesław; Schröder, Andreas; Boden, Fritz; Ludwikowski, Krzysztof

    2017-06-01

    The rapid progress of light emitting diode (LED) technology has recently resulted in the availability of high power devices with unprecedented light emission intensities comparable to those of visible laser light sources. On this basis two versatile devices have been developed, constructed and tested. The first one is a high-power, single-LED illuminator equipped with exchangeable projection lenses providing a homogenous light spot of defined diameter. The second device is a multi-LED illuminator array consisting of a number of high-power LEDs, each integrated with a separate collimating lens. These devices can emit R, G, CG, B, UV or white light and can be operated in pulsed or continuous wave (CW) mode. Using an external trigger signal they can be easily synchronized with cameras or other devices. The mode of operation and all parameters can be controlled by software. Various experiments have shown that these devices have become a versatile and competitive alternative to laser and xenon lamp based light sources. The principle, design, achieved performances and application examples are given in this paper.

  10. Optical, microphysical and radiative properties of aerosols over a tropical rural site in Kenya, East Africa: Source identification, modification and aerosol type discrimination

    Science.gov (United States)

    Boiyo, Richard; Kumar, K. Raghavendra; Zhao, Tianliang

    2018-03-01

    A better understanding of aerosol optical, microphysical and radiative properties is a crucial challenge for climate change studies. In the present study, column-integrated aerosol optical and radiative properties observed at a rural site, Mbita (0.42°S, 34.20 °E, and 1125 m above sea level) located in Kenya, East Africa (EA) are investigated using ground-based Aerosol Robotic Network (AERONET) data retrieved during January, 2007 to December, 2015. The annual mean aerosol optical depth (AOD500 nm), Ångström exponent (AE440-870 nm), fine mode fraction of AOD500 nm (FMF500 nm), and columnar water vapor (CWV, cm) were found to be 0.23 ± 0.08, 1.01 ± 0.16, 0.60 ± 0.07, and 2.72 ± 0.20, respectively. The aerosol optical properties exhibited a unimodal distribution with substantial seasonal heterogeneity in their peak values being low (high) during the local wet (dry) seasons. The observed data showed that Mbita and its environs are significantly influenced by various types of aerosols, with biomass burning and/or urban-industrial (BUI), mixed (MXD), and desert dust (DDT) aerosol types contributing to 37.72%, 32.81%, and 1.40%, respectively during the local dry season (JJA). The aerosol volume size distribution (VSD) exhibited bimodal lognormal structure with a geometric mean radius of 0.15 μm and 3.86-5.06 μm for fine- and coarse-mode aerosols, respectively. Further, analysis of single scattering albedo (SSA), asymmetry parameter (ASY) and refractive index (RI) revealed dominance of fine-mode absorbing aerosols during JJA. The averaged aerosol direct radiative forcing (ARF) retrieved from the AERONET showed a strong cooling effect at the bottom of the atmosphere (BOA) and significant warming within the atmosphere (ATM), representing the important role of aerosols played in this rural site of Kenya. Finally, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model revealed that aerosols from distinct sources resulted in enhanced loading

  11. Ultra-low noise supercontinuum source for ultra-high resolution optical coherence tomography at 1300 nm

    DEFF Research Database (Denmark)

    Bravo Gonzalo, Ivan; Maria, Michael; Engelsholm, Rasmus Dybbro

    2018-01-01

    of OCT, resulting in a reduced signal-to-noise ratio (SNR) [10-12]. Much work has been done to reduce the noise of the SC sources for instance with fiber tapers [7,8] or increasing the repetition rate of the pump laser for averaging in the spectrometer [10,12]. An alternative approach is to use all......-normal dispersion (ANDi) fibers [13,14] to generate SC light from well-known coherent nonlinear processes [15-17]. In fact, reduction of SC noise using ANDi fibers compared to anomalous dispersion SC pumped by sub-picosecond pulses has been recently demonstrated [18], but a cladding mode was used to stabilize...

  12. Aerosol optical properties in the mega-cities Beijing and Guangzhou: Measurements and implications for regional air pollution, aerosol sources and remote sensing

    Science.gov (United States)

    Garland, R. M.; Yang, H.; Schmid, O.; Rose, D.; Gunthe, S. S.

    2009-04-01

    Aerosol optical properties were measured in two mega-city regions in China. The first site (Backgarden) was in a rural area approximately 60 km northwest of the mega-city Guangzhou in south China and was part of the "Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta" intensive campaign in July 2006 (PRIDE-PRD2006). The second site (Yufa) was in a suburban area approximately 40 km south of Beijing and was part of "Campaigns of Air Quality Research in Beijing" (CAREBeijing-2006) in August 2006. Both sites were designed to measure the regional pollution of the mega-cities. The optical parameters determined with a nephelometer and photoacoustic spectrometer include absorption and scattering coefficients, single scattering albedos and Angstrom exponents at multiple wavelengths (450-700 nm). In both measurement campaigns, we observed pronounced diurnal cycles in absorption and scattering coefficients and single scattering albedo, which can be explained by boundary layer mixing effects and enhanced light absorbing carbon emissions from traffic activity during the nighttime and early morning, respectively (diesel soot from regulated truck traffic). In Beijing both the extensive and the intensive properties were highly dependent upon the origin of the air mass, which indicates that not only does the aerosol concentration change with air mass origin, but so do the chemical composition and sources. When the measured air masses originated in the north and passed over Beijing, the single scattering albedo was generally low (transported into the city from the south. The scattering and absorption coefficients measured in the outflow of the Guangzhou area during PRIDE-PRD2006 were ~2 times smaller than the southerly inflow into Beijing during CARBeijing-2006, which indicates that the sources of particulate pollution south of Beijing are even stronger than those in the Pearl River Delta. In both mega-city regions the Angstrom exponent exhibited a

  13. Optical tomography of tissues

    International Nuclear Information System (INIS)

    Zimnyakov, D A; Tuchin, Valerii V

    2002-01-01

    Methods of optical tomography of biological tissues are considered, which include pulse-modulation and frequency-modulation tomography, diffusion tomography with the use of cw radiation sources, optical coherent tomography, speckle-correlation tomography of nonstationary media, and optoacoustic tomography. The method for controlling the optical properties of tissues is studied from the point of view of increasing a probing depth in optical coherent tomography. The modern state and prospects of the development of optical tomography are discussed. (review)

  14. Long ranging swept-source optical coherence tomography-based angiography outperforms its spectral-domain counterpart in imaging human skin microcirculations

    Science.gov (United States)

    Xu, Jingjiang; Song, Shaozhen; Men, Shaojie; Wang, Ruikang K.

    2017-11-01

    There is an increasing demand for imaging tools in clinical dermatology that can perform in vivo wide-field morphological and functional examination from surface to deep tissue regions at various skin sites of the human body. The conventional spectral-domain optical coherence tomography-based angiography (SD-OCTA) system is difficult to meet these requirements due to its fundamental limitations of the sensitivity roll-off, imaging range as well as imaging speed. To mitigate these issues, we demonstrate a swept-source OCTA (SS-OCTA) system by employing a swept source based on a vertical cavity surface-emitting laser. A series of comparisons between SS-OCTA and SD-OCTA are conducted. Benefiting from the high system sensitivity, long imaging range, and superior roll-off performance, the SS-OCTA system is demonstrated with better performance in imaging human skin than the SD-OCTA system. We show that the SS-OCTA permits remarkable deep visualization of both structure and vasculature (up to ˜2 mm penetration) with wide field of view capability (up to 18×18 mm2), enabling a more comprehensive assessment of the morphological features as well as functional blood vessel networks from the superficial epidermal to deep dermal layers. It is expected that the advantages of the SS-OCTA system will provide a ground for clinical translation, benefiting the existing dermatological practice.

  15. TiO2 nanoparticles as exogenous contrast agent for 1 µm swept source optical coherence tomography: an in vitro study

    Science.gov (United States)

    Kumar, Atul; Mondal, Indranil; Roy, Poulomi; Poddar, Raju

    2018-03-01

    Optical coherence tomography (OCT) is a rapidly evolving, robust technology that has profoundly changed the practice of medical imaging. Swept source OCT (SSOCT) combines the standard time domain and the spatially encoded frequency domain OCT. We have employed a high-speed SSOCT system that utilizes a swept source laser with an A-scan rate of 100 kHz and a central wavelength of 1060 nm for the imaging of the tissue. SSOCT at 1060 nm allows for high penetration in the tissue. TiO2 nanoparticles (NPs) are mostly used for various experimental purposes as an exogenous imaging contrast agent. The in vitro imaging of chicken breast tissue is performed with and without the application of TiO2 NPs for exogenous contrast. Characterization of the chemically synthesized TiO2 NPs was done with dynamic light scattering and a scanning electron microscope method. The effect of TiO2 is studied at different exposure times. A significant improvement in the contrast to noise ratio has been observed through the in vitro imaging of a TiO2 treated tissue.

  16. Intense source of cold cesium atoms based on a two-dimensional magneto–optical trap with independent axial cooling and pushing

    International Nuclear Information System (INIS)

    Huang Jia-Qiang; Wu Chen-Fei; Wang Li-Jun; Yan Xue-Shu; Zhang Jian-Wei

    2016-01-01

    We report our studies on an intense source of cold cesium atoms based on a two-dimensional (2D) magneto–optical trap (MOT) with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a thin pushing laser beam to extract a cold atomic beam. With the independent pushing beam, the atomic flux can be substantially optimized. The total atomic flux maximum obtained in the 2D-HP MOT is 4.02 × 10 10 atoms/s, increased by 60 percent compared to the traditional 2D + MOT in our experiment. Moreover, with the pushing power 10 μW and detuning 0 Γ , the 2D-HP MOT can generate a rather intense atomic beam with the concomitant light shift suppressed by a factor of 20. The axial velocity distribution of the cold cesium beams centers at 6.8 m/s with an FMHW of about 2.8 m/s. The dependences of the atomic flux on the pushing power and detuning are studied in detail. The experimental results are in good agreement with the theoretical model. (paper)

  17. Design and validation of an open-source library of dynamic reference frames for research and education in optical tracking.

    Science.gov (United States)

    Brown, Alisa; Uneri, Ali; Silva, Tharindu De; Manbachi, Amir; Siewerdsen, Jeffrey H

    2018-04-01

    Dynamic reference frames (DRFs) are a common component of modern surgical tracking systems; however, the limited number of commercially available DRFs poses a constraint in developing systems, especially for research and education. This work presents the design and validation of a large, open-source library of DRFs compatible with passive, single-face tracking systems, such as Polaris stereoscopic infrared trackers (NDI, Waterloo, Ontario). An algorithm was developed to create new DRF designs consistent with intra- and intertool design constraints and convert to computer-aided design (CAD) files suitable for three-dimensional printing. A library of 10 such groups, each with 6 to 10 DRFs, was produced and tracking performance was validated in comparison to a standard commercially available reference, including pivot calibration, fiducial registration error (FRE), and target registration error (TRE). Pivot tests showed calibration error [Formula: see text], indistinguishable from the reference. FRE was [Formula: see text], and TRE in a CT head phantom was [Formula: see text], both equivalent to the reference. The library of DRFs offers a useful resource for surgical navigation research and could be extended to other tracking systems and alternative design constraints.

  18. Optical Coherence and Quantum Optics

    CERN Document Server

    Mandel, Leonard

    1995-01-01

    This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topi

  19. Advancing optical imaging for breast margin assessment: an analysis of excisional time, cautery, and patent blue dye on underlying sources of contrast.

    Directory of Open Access Journals (Sweden)

    Torre M Bydlon

    Full Text Available Breast conserving surgery (BCS is a recommended treatment for breast cancer patients where the goal is to remove the tumor and a surrounding rim of normal tissue. Unfortunately, a high percentage of patients return for additional surgeries to remove all of the cancer. Post-operative pathology is the gold standard for evaluating BCS margins but is limited due to the amount of tissue that can be sampled. Frozen section analysis and touch-preparation cytology have been proposed to address the surgical needs but also have sampling limitations. These issues represent an unmet clinical need for guidance in resecting malignant tissue intra-operatively and for pathological sampling. We have developed a quantitative spectral imaging device to examine margins intra-operatively. The context in which this technology is applied (intra-operative or post-operative setting is influenced by time after excision and surgical factors including cautery and the presence of patent blue dye (specifically Lymphazurin™, used for sentinel lymph node mapping. Optical endpoints of hemoglobin ([THb], fat ([β-carotene], and fibroglandular content via light scattering ( measurements were quantified from diffuse reflectance spectra of lumpectomy and mastectomy specimens using a Monte Carlo model. A linear longitudinal mixed-effects model was used to fit the optical endpoints for the cautery and kinetics studies. Monte Carlo simulations and tissue mimicking phantoms were used for the patent blue dye experiments. [THb], [β-carotene], and were affected by , and [β-carotene]/ was 40%. [β-carotene] and [β-carotene]/ were the only parameters not affected by cautery. This work demonstrates the importance of understanding the post-excision kinetics of ex-vivo tissue and the presence of cautery and patent blue dye for breast tumor margin assessment, to accurately interpret data and exploit underling sources of contrast.

  20. A pilot study to image the vascular network of small melanocytic choroidal tumors with speckle noise-free 1050-nm swept source optical coherence tomography (OCT choroidal angiography).

    Science.gov (United States)

    Maloca, Peter; Gyger, Cyrill; Hasler, Pascal W

    2016-06-01

    To visualize and measure the vascular network of melanocytic choroidal tumors with speckle noise-free swept source optical coherence tomography (SS-OCT choroidal angiography). Melanocytic choroidal tumors from 24 eyes were imaged with 1050-nm optical coherence tomography (Topcon DRI OCT-1 Atlantis). A semi-automated algorithm was developed to remove speckle noise and to extract and measure the volume of the choroidal vessels from the obtained OCT data. In all cases, analysis of the choroidal vessels could be performed with SS-OCT without the need for pupillary dilation. The proposed method allows speckle noise-free, structure-guided visualization and measurement of the larger choroidal vessels in three dimensions. The obtained data suggest that speckle noise-free OCT may be more effective at identifying choroidal structures than traditional OCT methods. The measured volume of the extracted choroidal vessels of Haller's layer and Sattler's layer in the examined tumorous eyes was on average 0.982463955 mm(3) /982463956 μm(3) (range of 0.209764406 mm(3) /209764405.9 μm(3)to 1.78105544 mm(3) /1781055440 μm(3)). Full thickness obstruction of the choroidal vasculature by the tumor was found in 18 cases (72 %). In seven cases (18 %), choroidal vessel architecture did not show pronounced morphological abnormalities (18 %). Speckle noise-free OCT may serve as a new illustrative imaging technology and enhance visualization of the choroidal vessels without the need for dye injection. OCT can be used to identify and evaluate the choroidal vessels of melanocytic choroidal tumors, and may represent a potentially useful tool for imaging and monitoring of choroidal nevi and melanoma.

  1. Assessing the sources and magnitude of diurnal nitrate variability in the San Joaquin River (California) with an in situ optical nitrate sensor and dual nitrate isotopes

    Science.gov (United States)

    Pellerin, Brian A.; Downing, Bryan D.; Kendall, Carol; Dahlgren, Randy A.; Kraus, Tamara E.C.; Saraceno, John Franco; Spencer, Robert G. M.; Bergamaschi, Brian A.

    2009-01-01

    1. We investigated diurnal nitrate (NO3−) concentration variability in the San Joaquin River using an in situ optical NO3− sensor and discrete sampling during a 5‐day summer period characterized by high algal productivity. Dual NO3− isotopes (δ15NNO3 and δ18ONO3) and dissolved oxygen isotopes (δ18ODO) were measured over 2 days to assess NO3− sources and biogeochemical controls over diurnal time‐scales.2. Concerted temporal patterns of dissolved oxygen (DO) concentrations and δ18ODOwere consistent with photosynthesis, respiration and atmospheric O2 exchange, providing evidence of diurnal biological processes independent of river discharge.3. Surface water NO3− concentrations varied by up to 22% over a single diurnal cycle and up to 31% over the 5‐day study, but did not reveal concerted diurnal patterns at a frequency comparable to DO concentrations. The decoupling of δ15NNO3 and δ18ONO3isotopes suggests that algal assimilation and denitrification are not major processes controlling diurnal NO3− variability in the San Joaquin River during the study. The lack of a clear explanation for NO3− variability likely reflects a combination of riverine biological processes and time‐varying physical transport of NO3− from upstream agricultural drains to the mainstem San Joaquin River.4. The application of an in situ optical NO3− sensor along with discrete samples provides a view into the fine temporal structure of hydrochemical data and may allow for greater accuracy in pollution assessment.

  2. Perspectives of imaging of single protein molecules with the present design of the European XFEL. Pt. 1. X-ray source, beamline optics and instrument simulations

    International Nuclear Information System (INIS)

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni; Zagorodnov, Igor; Geloni, Gianluca; Yefanov, Oleksandr

    2014-08-01

    The Single Particles, Clusters and Biomolecules (SPB) instrument at the European XFEL is located behind the SASE1 undulator, and aims to support imaging and structure determination of biological specimen between about 0.1 μm and 1 μm size. The instrument is designed to work at photon energies from 3 keV up to 16 keV. This wide operation range is a cause for challenges to the focusing optics. In particular, a long propagation distance of about 900 m between X-ray source and sample leads to a large lateral photon beam size at the optics. The beam divergence is the most important parameter for the optical system, and is largest for the lowest photon energies and for the shortest pulse duration (corresponding to the lowest charge). Due to the large divergence of nominal X-ray pulses with duration shorter than 10 fs, one suffers diffraction from mirror aperture, leading to a 100-fold decrease in fluence at photon energies around 4 keV, which are ideal for imaging of single biomolecules. The nominal SASE1 output power is about 50 GW. This is very far from the level required for single biomolecule imaging, even assuming perfect beamline and focusing efficiency. Here we demonstrate that the parameters of the accelerator complex and of the SASE1 undulator offer an opportunity to optimize the SPB beamline for single biomolecule imaging with minimal additional costs and time. Start to end simulations from the electron injector at the beginning of the accelerator complex up to the generation of diffraction data indicate that one can achieve diffraction without diffraction with about 0.5 photons per Shannon pixel at near-atomic resolution with 10 13 photons in a 4 fs pulse at 4 keV photon energy and in a 100 nm focus, corresponding to a fluence of 10 23 ph/cm 2 . This result is exemplified using the RNA Pol II molecule as a case study.

  3. Perspectives of imaging of single protein molecules with the present design of the European XFEL. Pt. 1. X-ray source, beamline optics and instrument simulations

    Energy Technology Data Exchange (ETDEWEB)

    Serkez, Svitozar; Kocharyan, Vitali; Saldin, Evgeni; Zagorodnov, Igor [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Yefanov, Oleksandr [Center for Free-Electron Laser Science, Hamburg (Germany)

    2014-08-15

    The Single Particles, Clusters and Biomolecules (SPB) instrument at the European XFEL is located behind the SASE1 undulator, and aims to support imaging and structure determination of biological specimen between about 0.1 μm and 1 μm size. The instrument is designed to work at photon energies from 3 keV up to 16 keV. This wide operation range is a cause for challenges to the focusing optics. In particular, a long propagation distance of about 900 m between X-ray source and sample leads to a large lateral photon beam size at the optics. The beam divergence is the most important parameter for the optical system, and is largest for the lowest photon energies and for the shortest pulse duration (corresponding to the lowest charge). Due to the large divergence of nominal X-ray pulses with duration shorter than 10 fs, one suffers diffraction from mirror aperture, leading to a 100-fold decrease in fluence at photon energies around 4 keV, which are ideal for imaging of single biomolecules. The nominal SASE1 output power is about 50 GW. This is very far from the level required for single biomolecule imaging, even assuming perfect beamline and focusing efficiency. Here we demonstrate that the parameters of the accelerator complex and of the SASE1 undulator offer an opportunity to optimize the SPB beamline for single biomolecule imaging with minimal additional costs and time. Start to end simulations from the electron injector at the beginning of the accelerator complex up to the generation of diffraction data indicate that one can achieve diffraction without diffraction with about 0.5 photons per Shannon pixel at near-atomic resolution with 10{sup 13} photons in a 4 fs pulse at 4 keV photon energy and in a 100 nm focus, corresponding to a fluence of 10{sup 23}ph/cm{sup 2}. This result is exemplified using the RNA Pol II molecule as a case study.

  4. A pyrazolyl-based thiolato single-source precursor for the selective synthesis of isotropic copper-deficient copper(I) sulfide nanocrystals: synthesis, optical and photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Gopinath; Santra, Ananyakumari; Bera, Pradip; Acharjya, Moumita [Vidyasagar University, Post Graduate Department of Chemistry, Panskura Banamali College (India); Jana, Sumanta [Indian Institute of Engineering Science and Technology (IIEST), Department of Chemistry (India); Chattopadhyay, Dipankar [University of Calcutta, Department of Polymer Science and Technology (India); Mondal, Anup [Indian Institute of Engineering Science and Technology (IIEST), Department of Chemistry (India); Seok, Sang Il [Korea Research Institute of Chemical Technology, KRICT-EPFL Global Research Laboratory, Division of Advanced Materials (Korea, Republic of); Bera, Pulakesh, E-mail: pbera.pbc.chem@gmail.com [Vidyasagar University, Post Graduate Department of Chemistry, Panskura Banamali College (India)

    2016-10-15

    Hexagonal copper-deficient copper(I) sulfide (Cu{sub 2-x}S, x = 0.03, 0.2) nanocrystals (NCs) are synthesized from a newly prepared single-source precursor (SP), [Cu(bdpa){sub 2}][CuCl{sub 2}], where bdpa is benzyl 3,5-dimethyl-pyrazole-1-carbodithioate. The SP is crystallized with space group Pī and possesses a distorted tetrahedron structure with a CuN{sub 2}S{sub 2} chromophore where the central copper is in +1 oxidation state. Distortion in copper(I) structure and the low decomposition temperature of SP make it favorable for the low-temperature solvent-assisted selective growth of high-copper content sulfides. The nucleation and growth of Cu{sub 2-x}S (x = 0.03, 0.2) are effectively controlled by the SP and the solvent in the solvothermal decomposition process. During decomposition, fragment benzyl thiol (PhCH{sub 2}SH) from SP effectively passivates the nucleus leading to spherical nanocrystals. Further, solvent plays an important role in the selective thermochemical transformation of Cu{sup I}-complex to Cu{sub 2-x}S (x = 0.03, 0.2) NCs. The chelating binders (solvent) like ethylene diamine (EN) and ethylene glycol (EG) prefer to form spherical Cu{sub 1.97}S nanoparticles (djurleite), whereas nonchelating hydrazine hydrate (HH) shows the tendency to furnish hexagonal platelets of copper-deficient Cu{sub 1.8}S. The optical band gap values (2.25–2.50 eV) show quantum confinement effect in the structure. The synthesized NCs display excellent catalytic activity (~87 %) toward photodegradation of organic dyes like Congo Red (CR) and Methylene Blue (MB).Graphical abstractA pyrazolyl-based thiolato single-source precursor for the selective synthesis of isotropic copper-deficient copper(I) sulfide nanocrystals: Synthesis, optical and photocatalytic activity.Gopinath Mondal, Ananyakumari Santra, Pradip Bera, Moumita Acharjya, Sumanta Jana, Dipankar Chattopadhyay, Anup Mondal, Sang Il Seok, Pulakesh Bera.

  5. Real-time calibration-free C-scan images of the eye fundus using Master Slave swept source optical coherence tomography

    Science.gov (United States)

    Bradu, Adrian; Kapinchev, Konstantin; Barnes, Fred; Garway-Heath, David F.; Rajendram, Ranjan; Keane, Pearce; Podoleanu, Adrian G.

    2015-03-01

    Recently, we introduced a novel Optical Coherence Tomography (OCT) method, termed as Master Slave OCT (MS-OCT), specialized for delivering en-face images. This method uses principles of spectral domain interfereometry in two stages. MS-OCT operates like a time domain OCT, selecting only signals from a chosen depth only while scanning the laser beam across the eye. Time domain OCT allows real time production of an en-face image, although relatively slowly. As a major advance, the Master Slave method allows collection of signals from any number of depths, as required by the user. The tremendous advantage in terms of parallel provision of data from numerous depths could not be fully employed by using multi core processors only. The data processing required to generate images at multiple depths simultaneously is not achievable with commodity multicore processors only. We compare here the major improvement in processing and display, brought about by using graphic cards. We demonstrate images obtained with a swept source at 100 kHz (which determines an acquisition time [Ta] for a frame of 200×200 pixels2 of Ta =1.6 s). By the end of the acquired frame being scanned, using our computing capacity, 4 simultaneous en-face images could be created in T = 0.8 s. We demonstrate that by using graphic cards, 32 en-face images can be displayed in Td 0.3 s. Other faster swept source engines can be used with no difference in terms of Td. With 32 images (or more), volumes can be created for 3D display, using en-face images, as opposed to the current technology where volumes are created using cross section OCT images.

  6. Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography.

    Science.gov (United States)

    Chansangpetch, Sunee; Nguyen, Anwell; Mora, Marta; Badr, Mai; He, Mingguang; Porco, Travis C; Lin, Shan C

    2018-03-01

    To assess the interdevice agreement between swept-source Fourier-domain and time-domain anterior segment optical coherence tomography (AS-OCT). Fifty-three eyes from 41 subjects underwent CASIA2 and Visante OCT imaging. One hundred eighty-degree axis images were measured with the built-in two-dimensional analysis software for the swept-source Fourier-domain AS-OCT (CASIA2) and a customized program for the time-domain AS-OCT (Visante OCT). In both devices, we examined the angle opening distance (AOD), trabecular iris space area (TISA), angle recess area (ARA), anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). Bland-Altman plots and intraclass correlation (ICC) were performed. Orthogonal linear regression assessed any proportional bias. ICC showed strong correlation for LV (0.925) and ACD (0.992) and moderate agreement for ACW (0.801). ICC suggested good agreement for all angle parameters (0.771-0.878) except temporal AOD500 (0.743) and ARA750 (nasal 0.481; temporal 0.481). There was a proportional bias in nasal ARA750 (slope 2.44, 95% confidence interval [CI]: 1.95-3.18), temporal ARA750 (slope 2.57, 95% CI: 2.04-3.40), and nasal TISA500 (slope 1.30, 95% CI: 1.12-1.54). Bland-Altman plots demonstrated in all measured parameters a minimal mean difference between the two devices (-0.089 to 0.063); however, evidence of constant bias was found in nasal AOD250, nasal AOD500, nasal AOD750, nasal ARA750, temporal AOD500, temporal AOD750, temporal ARA750, and ACD. Among the parameters with constant biases, CASIA2 tends to give the larger numbers. Both devices had generally good agreement. However, there were proportional and constant biases in most angle parameters. Thus, it is not recommended that values be used interchangeably.

  7. In vivo microvascular imaging of human oral and nasal cavities using swept-source optical coherence tomography with a single forward/side viewing probe

    Science.gov (United States)

    Choi, Woo June; Wang, Ruikang K.

    2015-03-01

    We report three-dimensional (3D) imaging of microcirculation within human cavity tissues in vivo using a high-speed swept-source optical coherence tomography (SS-OCT) at 1.3 μm with a modified probe interface. Volumetric structural OCT images of the inner tissues of oral and nasal cavities are acquired with a field of view of 2 mm x 2 mm. Two types of disposable and detachable probe attachments are devised and applied to the port of the imaging probe of OCT system, enabling forward and side imaging scans for selective and easy access to specific cavity tissue sites. Blood perfusion is mapped with OCT-based microangiography from 3D structural OCT images, in which a novel vessel extraction algorithm is used to decouple dynamic light scattering signals, due to moving blood cells, from the background scattering signals due to static tissue elements. Characteristic tissue anatomy and microvessel architectures of various cavity tissue regions of a healthy human volunteer are identified with the 3D OCT images and the corresponding 3D vascular perfusion maps at a level approaching capillary resolution. The initial finding suggests that the proposed method may be engineered into a promising tool for evaluating and monitoring tissue microcirculation and its alteration within a wide-range of cavity tissues in the patients with various pathological conditions.

  8. High-resolution optical coherence tomography using broadband light source with strain-controlled InAs/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Tsubaki, Ippei; Harada, Yukihiro; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2012-12-15

    Recently, there has been an increasing interest in broadband light sources to develop a biomolecular imaging technique called optical coherence tomography (OCT). We fabricated superluminescent diodes (SLDs) using three kinds of quantum dot (QD) layers with different emission wavelength in the active region. The emission wavelength was controlled by reducing the strain in QDs by using In{sub 0.1}Ga{sub 0.9}As strain-reducing layer. The SLD device showed a broad electroluminescence spectrum with the center wavelength of 1104 nm and the spectral linewidth of 122 nm at the injection of 40 mA, which corresponds to the theoretical axial resolution of 4.4 {mu}m. To estimate the actual resolution of the OCT system using fabricated SLD, we measured the interference signal in the Michelson interferometer. An axial resolution of 5.4 {mu}m, which is close to the theoretical limit, was obtained (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. In vivo layer visualization of rat olfactory bulb by a swept source optical coherence tomography and its confirmation through electrocoagulation and anatomy

    Science.gov (United States)

    Watanabe, Hideyuki; Rajagopalan, Uma Maheswari; Nakamichi, Yu; Igarashi, Kei M.; Madjarova, Violeta Dimitrova; Kadono, Hirofumi; Tanifuji, Manabu

    2011-01-01

    Here, we report in vivo 3-D visualization of the layered organization of a rat olfactory bulb (OB) by a swept source optical coherence tomography (SS-OCT). The SS-OCT operates at a wavelength of 1334 nm with respective theoretical depth and lateral resolutions of 6.7 μm and 15.4 μm in air and hence it is possible to get a 3D structural map of OB in vivo at the micron level resolution with millimeter-scale imaging depth. Up until now, with methods such as MRI, confocal microscopy, OB depth structure in vivo had not been clearly visualized as these do not satisfy the criterion of simultaneously providing micron-scale spatial resolution and imaging up to a few millimeter in depth. In order to confirm the OB’s layered organization revealed by SS-OCT, we introduced the technique of electrocoagulation to make landmarks across the layered structure. To our knowledge this is such a first study that combines electrocoagulation and OCT in vivo of rat OB. Our results confirmed the layered organization of OB, and moreover the layers were clearly identified by electrocoagulation landmarks both in the OCT structural and anatomical slice images. We expect such a combined study is beneficial for both OCT and neuroscience fields. PMID:21833364

  10. Investigation of firing temperature variation in ovens for ceramic-fused-to-metal dental prostheses using swept source optical coherence tomography

    Science.gov (United States)

    Todor, Raluca; Negrutiu, Meda-Lavinia; Sinescu, Cosmin; Topala, Florin Ionel; Bradu, Adrian; Duma, Virgil-Florin; Romînu, Mihai; Podoleanu, Adrian G.

    2018-03-01

    One of the most common fabrication techniques for dental ceramics is sintering, a process of heating of the ceramic to ensure densification. This occurs by viscous flow when the firing temperature is reached. Acceptable restorations require the alloy and ceramic to be chemically, thermally, mechanically, and aesthetically compatible. Thermal and mechanical compatibility include a fusing temperature of ceramic that does not cause distortion of the metal substructure. Decalibration of ovens used for firing of the ceramic layers for metal ceramic dental prostheses leads to stress and cracks in the veneering material, and ultimately to the failure of the restoration. 25 metal ceramic prostheses were made for this study. They were divided in five groups, each sintered at a different temperature: a group at the temperature prescribed by the producer, two groups at lower and two groups at higher temperatures set in the ceramic oven. An established noninvasive biomedical imaging method, swept source (SS) optical coherence tomography (OCT) was employed, in order to evaluate the modifications induced when using temperatures different from those prescribed for firing the samples. A quantitative assessment of the probes is performed by en-face OCT images, taken at constant depths inside the samples. The differences in granulation, thus in reflectivity allow for extracting rules-of-thumb to evaluate fast, by using only the prostheses currently produced the current calibration of the ceramic oven. OCT imaging can allow quick identification of the oven decalibration, to avoid producing dental prostheses with defects.

  11. Optical and mechanical design of the extended x-ray absorption fine structure (EXAFS) beam-line at Indus-II synchrotron source

    International Nuclear Information System (INIS)

    Das, N.C.; Jha, S.N.; Bhattacharyya, D.; Sinha, A.K.; Mishra, V.K.; Verma, Vishnu; Ghosh, A.K.

    2002-11-01

    An extended x-ray absorption fine structure (EXAFS) beam line for x-ray absorption studies using energy dispersive geometry and position sensitive detector is being designed for the INDUS-II Synchrotron source. The beam line would be used for doing x-ray absorption experiments involving measurements of fme structures above the absorption edge of different species of atoms in a material The results of the above experiments would lead to the determination of different important structural parameters of materials viz.. inter-atomic distance. co-ordination number, degree of disorder and radial distribution function etc. The optical design of the beam line has been completed based on the working principle that a single crystal bent in the shape of an ellipse by a crystal bender would act as a dispersing as well as focusing element. The mechanical design of the beam line including the crystal bender has also been completed and discussed here. Calculations have been done to detennine the temperature profile on the different components of the beam line under exposure to synchrotron radiation and proper cooling channels have been designed to bring down the heat load on the components. (author)

  12. Positron sources

    International Nuclear Information System (INIS)

    Chehab, R.

    1994-01-01

    A tentative survey of positron sources is given. Physical processes on which positron generation is based are indicated and analyzed. Explanation of the general features of electromagnetic interactions and nuclear β + decay makes it possible to predict the yield and emittance for a given optical matching system between the positron source and the accelerator. Some kinds of matching systems commonly used - mainly working with solenoidal field - are studied and the acceptance volume calculated. Such knowledge is helpful in comparing different matching systems. Since for large machines, a significant distance exists between the positron source and the experimental facility, positron emittance has to be preserved during beam transfer over large distances and methods used for that purpose are indicated. Comparison of existing positron sources leads to extrapolation to sources for future linear colliders. Some new ideas associated with these sources are also presented. (orig.)

  13. Nonlinear Optics and Applications

    Science.gov (United States)

    Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)

    2007-01-01

    Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.

  14. Comparison of Laser and Stereo Optical, SAR and InSAR Point Clouds from Air- and Space-Borne Sources in the Retrieval of Forest Inventory Attributes

    Directory of Open Access Journals (Sweden)

    Xiaowei Yu

    2015-11-01

    satellite optical image gave similar results for Hg and Dg, which were only slightly worse than those of ALS data. As expected, spaceborne SAR data produced the worst estimates. WorldView-2 satellite data performed well, achieving accuracy comparable to the one with ALS data for G, VOL and AGB estimation. SAR interferometry data seems to contain more information for forest inventory than SAR radargrammetry and reach a better accuracy (relative RMSE decreased from 13.4% to 9.5% for Hg, 20.6% to 19.2% for Dg, 25.8% to 20.9% for G, 31.2% to 22.0% for VOL and 27.5% to 20.7% for AGB, respectively. However, the availability of interferometry data is limited. The results confirmed the high potential of all 3D remote sensing data sources for forest inventory purposes. However, the assumption of using other than ALS data is that there exist a high quality digital terrain model, in our case it was derived from ALS.

  15. Optical materials

    International Nuclear Information System (INIS)

    Poker, D.B.; Ortiz, C.

    1989-01-01

    This book reports on: Diamond films, Synthesis of optical materials, Structure related optical properties, Radiation effects in optical materials, Characterization of optical materials, Deposition of optical thin films, and Optical fibers and waveguides

  16. Positron sources

    International Nuclear Information System (INIS)

    Chehab, R.

    1989-01-01

    A tentative survey of positron sources is given. Physical processes on which positron generation is based are indicated and analyzed. Explanation of the general features of electromagnetic interactions and nuclear β + decay makes it possible to predict the yield and emittance for a given optical matching system between the positron source and the accelerator. Some kinds of matching systems commonly used - mainly working with solenoidal fields - are studied and the acceptance volume calculated. Such knowledge is helpful in comparing different matching systems. Since for large machines, a significant distance exists between the positron source and the experimental facility, positron emittance has to be preserved during beam transfer over large distances and methods used for that purpose are indicated. Comparison of existing positron sources leads to extrapolation to sources for future linear colliders

  17. X-Ray and Optical Study of the Gamma-ray Source 3FGL J0838.8–2829: Identification of a Candidate Millisecond Pulsar Binary and an Asynchronous Polar

    Energy Technology Data Exchange (ETDEWEB)

    Halpern, Jules P.; Bogdanov, Slavko [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027-6601 (United States); Thorstensen, John R., E-mail: jules@astro.columbia.edu [Department of Physics and Astronomy, 6127 Wilder Laboratory, Dartmouth College, Hanover, NH 03755-3528 (United States)

    2017-04-01

    We observed the field of the Fermi source 3FGL J0838.8−2829 in optical and X-rays, initially motivated by the cataclysmic variable (CV) 1RXS J083842.1−282723 that lies within its error circle. Several X-ray sources first classified as CVs have turned out to be γ -ray emitting millisecond pulsars (MSPs). We find that 1RXS J083842.1−282723 is in fact an unusual CV, a stream-fed asynchronous polar in which accretion switches between magnetic poles (that are ≈120° apart) when the accretion rate is at minimum. High-amplitude X-ray modulation at periods of 94.8 ± 0.4 minutes and 14.7 ± 1.2 hr are seen. The former appears to be the spin period, while the latter is inferred to be one-third of the beat period between the spin and the orbit, implying an orbital period of 98.3 ± 0.5 minutes. We also measure an optical emission-line spectroscopic period of 98.413 ± 0.004 minutes, which is consistent with the orbital period inferred from the X-rays. In any case, this system is unlikely to be the γ -ray source. Instead, we find a fainter variable X-ray and optical source, XMMU J083850.38−282756.8, that is modulated on a timescale of hours in addition to exhibiting occasional sharp flares. It resembles the black widow or redback pulsars that have been discovered as counterparts of Fermi sources, with the optical modulation due to heating of the photosphere of a low-mass companion star by, in this case, an as-yet undetected MSP. We propose XMMU J083850.38−282756.8 as the MSP counterpart of 3FGL J0838.8−2829.

  18. Limit of detection of a fiber optics gyroscope using a super luminescent radiation source; Limite de deteccion de un giroscopio de fibra optica usando una fuente de radiacion superluminiscente

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval R, G.E. [Laboratorio de Optica Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, 04510 Mexico D.F. (Mexico); Nikolaev, V.A. [Departamento de Optica y Radiofisica Cuantica, Universidad Estatal de Telecomunicaciones de San Petersburgo, M.A. Bonch-Bruyevich, Kanal Moika 61, Saint Petersburg 191186, (Russian Federation)

    2003-07-01

    The main objective of this work is to establish the dependence of characteristics of the fiber optics gyroscope (FOG) with respect to the parameters of the super luminescent emission source based on doped optical fiber with rare earth elements (Super luminescent Fiber Source, SFS), argument the pumping rate election of the SFS to obtain characteristics limits of the FOG sensibility. By using this type of emission source in the FOG is recommend to use the rate when the direction of the pumping signal coincide with the super luminescent signal. The most results are the proposition and argumentation of the SFS election as emission source to be use in the FOG of the phase type. Such a decision allow to increase the characteristics of the FOG sensibility in comparison with the use of luminescent source of semiconductors emission which are extensively used in the present time. The use of emission source of the SFS type allow to come closer to the threshold of the obtained sensibility limit (detection limit) which is determined with the shot noise. (Author)

  19. Robust sampling-sourced numerical retrieval algorithm for optical energy loss function based on log–log mesh optimization and local monotonicity preserving Steffen spline

    Energy Technology Data Exchange (ETDEWEB)

    Maglevanny, I.I., E-mail: sianko@list.ru [Volgograd State Social Pedagogical University, 27 Lenin Avenue, Volgograd 400131 (Russian Federation); Smolar, V.A. [Volgograd State Technical University, 28 Lenin Avenue, Volgograd 400131 (Russian Federation)

    2016-01-15

    We introduce a new technique of interpolation of the energy-loss function (ELF) in solids sampled by empirical optical spectra. Finding appropriate interpolation methods for ELFs poses several challenges. The sampled ELFs are usually very heterogeneous, can originate from various sources thus so called “data gaps” can appear, and significant discontinuities and multiple high outliers can be present. As a result an interpolation based on those data may not perform well at predicting reasonable physical results. Reliable interpolation tools, suitable for ELF applications, should therefore satisfy several important demands: accuracy and predictive power, robustness and computational efficiency, and ease of use. We examined the effect on the fitting quality due to different interpolation schemes with emphasis on ELF mesh optimization procedures and we argue that the optimal fitting should be based on preliminary log–log scaling data transforms by which the non-uniformity of sampled data distribution may be considerably reduced. The transformed data are then interpolated by local monotonicity preserving Steffen spline. The result is a piece-wise smooth fitting curve with continuous first-order derivatives that passes through all data points without spurious oscillations. Local extrema can occur only at grid points where they are given by the data, but not in between two adjacent grid points. It is found that proposed technique gives the most accurate results and also that its computational time is short. Thus, it is feasible using this simple method to address practical problems associated with interaction between a bulk material and a moving electron. A compact C++ implementation of our algorithm is also presented.

  20. Premonsoon aerosol optical properties from AERONET retrievals and its probable source fields in Eastern India urban environment (Kolkata): evaluating spatial variability and its comparison with MODIS retrievals.

    Science.gov (United States)

    Priyadharshini, B.; Verma, S.

    2015-12-01

    Aerosol characteristics were examined using Aerosol Robotic Network (AERONET) and MODIS retrievals (Moderate Resolution Imaging Spectroradiometer) during the period, February to June 2009 in Eastern India, Kolkata (KOL). AERONET retrievals results for the study period manifested an aerosol optical depth - AOD (Angstrom exponent - α) in the range 0.65 - 0.81 (0.66 - 0.97) with an intermittent influence of dust. A substantial dominance of finer (coarser) particles were found in February (April) and an equal dominance of both in June. Aerosol size distribution (ASD) revealed a high volume in fine mode during June and that in April for the coarse mode. A few areas of in and around KOL, Odisha, and Sikkim influenced AOD ascertained using the Potential source contribution function (PSCF). Cluster analysis revealed preferred pathway as continental during February and both continental and marine during March to June. Episodic days identified for dust occurrence was examined and was further corroborated by MODIS Rapid response images. Further, comparative results of seven collateral AERONET sites in India, revealed a high AOD (α) at KOL during February to May (March and April) with Fine mode - FM (Coarse mode - CM) AOD of KOL being high during March and April (February to April) than other locations. Single scattering albedo (SSA) at 0.67 μm at KOL was slightly lower during February and March, with being equivalent and or higher than other sites during April to June. Comparison of AERONET - MODIS AOD at 0.55 µm for KOL (entire study period) for the collateral days revealed underestimation of MODIS during February to April and overestimation during May and June than AERONET. AERONET - MODIS AOD comparison for seven locations, during low (February) and high (June) aerosol loading, showed good agreement for few stations and divulged discrepancy for other sites.

  1. Robust sampling-sourced numerical retrieval algorithm for optical energy loss function based on log–log mesh optimization and local monotonicity preserving Steffen spline

    International Nuclear Information System (INIS)

    Maglevanny, I.I.; Smolar, V.A.

    2016-01-01

    We introduce a new technique of interpolation of the energy-loss function (ELF) in solids sampled by empirical optical spectra. Finding appropriate interpolation methods for ELFs poses several challenges. The sampled ELFs are usually very heterogeneous, can originate from various sources thus so called “data gaps” can appear, and significant discontinuities and multiple high outliers can be present. As a result an interpolation based on those data may not perform well at predicting reasonable physical results. Reliable interpolation tools, suitable for ELF applications, should therefore satisfy several important demands: accuracy and predictive power, robustness and computational efficiency, and ease of use. We examined the effect on the fitting quality due to different interpolation schemes with emphasis on ELF mesh optimization procedures and we argue that the optimal fitting should be based on preliminary log–log scaling data transforms by which the non-uniformity of sampled data distribution may be considerably reduced. The transformed data are then interpolated by local monotonicity preserving Steffen spline. The result is a piece-wise smooth fitting curve with continuous first-order derivatives that passes through all data points without spurious oscillations. Local extrema can occur only at grid points where they are given by the data, but not in between two adjacent grid points. It is found that proposed technique gives the most accurate results and also that its computational time is short. Thus, it is feasible using this simple method to address practical problems associated with interaction between a bulk material and a moving electron. A compact C++ implementation of our algorithm is also presented.

  2. Accuracy of Corneal Thickness by Swept-Source Optical Coherence Tomography and Scheimpflug Camera in Virgin and Treated Fuchs Endothelial Dystrophy.

    Science.gov (United States)

    Arnalich-Montiel, Francisco; Ortiz-Toquero, Sara; Auladell, Clara; Couceiro, Ana

    2018-06-01

    To assess intraobserver repeatability, intersession reproducibility, and agreement of swept-source Fourier-domain optical coherence tomography (SS-OCT) and the Scheimpflug camera in measuring corneal thickness in virgin and grafted eyes with Fuchs endothelial corneal dystrophy (FECD). Thirty-six control eyes, 35 FECD eyes, 30 FECD with corneal edema eyes, 25 Descemet stripping automated endothelial keratoplasty (DSAEK) eyes, and 29 Descemet membrane endothelial keratoplasty (DMEK) eyes were included. The apical center, pupillary center, and thinnest corneal thickness were determined in 3 consecutive images and repeated 2 weeks later. Repeatability and reproducibility coefficients, intraclass correlation coefficients, and 95% limits of agreement (LOA) between measurements were calculated. Agreement between devices was assessed using Bland-Altman analysis. Corneal thickness measurements were highly reproducible and repeatable with both systems. SS-OCT showed better repeatability in all corneal locations in the normal, FECD, FECD with edema, DSAEK, and DMEK groups (coefficient of variation ≤0.60%, ≤0.36%, ≤0.43%, ≤1.09%, and ≤0.48%, respectively) than the Scheimpflug (coefficient of variation ≤1.15%, ≤0.92%, ≤1.10%, ≤1.25%, and ≤1.14%, respectively). Between-session 95% LOA for SS-OCT was less than 3% for all groups except for the FECD with edema group, being almost double using the Scheimpflug camera. Differences between instruments were statistically significant in all groups and locations (P group (P ≤ 0.51); however, SS-OCT underestimated all measurements. SS-OCT provides better reproducible and repeatable measurements of corneal thickness than those obtained with the Scheimpflug camera in patients with FECD or an endothelial transplant. Variations between examinations higher than the 95% LOA observed in our study should raise awareness of changes in the endothelial function.

  3. Optical CDMA components requirements

    Science.gov (United States)

    Chan, James K.

    1998-08-01

    Optical CDMA is a complementary multiple access technology to WDMA. Optical CDMA potentially provides a large number of virtual optical channels for IXC, LEC and CLEC or supports a large number of high-speed users in LAN. In a network, it provides asynchronous, multi-rate, multi-user communication with network scalability, re-configurability (bandwidth on demand), and network security (provided by inherent CDMA coding). However, optical CDMA technology is less mature in comparison to WDMA. The components requirements are also different from WDMA. We have demonstrated a video transport/switching system over a distance of 40 Km using discrete optical components in our laboratory. We are currently pursuing PIC implementation. In this paper, we will describe the optical CDMA concept/features, the demonstration system, and the requirements of some critical optical components such as broadband optical source, broadband optical amplifier, spectral spreading/de- spreading, and fixed/programmable mask.

  4. Optical cavity furnace for semiconductor wafer processing

    Science.gov (United States)

    Sopori, Bhushan L.

    2014-08-05

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  5. Spectroscopic confirmation of the optical identification of X-ray sources used to determine accurate positions for the anomalous X-ray pulsars 1E 2259+58.6 and 4U 0142+61

    Science.gov (United States)

    van den Berg, M.; Verbunt, F.

    2001-03-01

    Optical spectra show that two proposed counterparts for X-ray sources detected near 1E 2259+58.6 are late G stars, and a proposed counterpart for a source near 4U 0142+61 is a dMe star. The X-ray luminosities are as expected for such stars. We thus confirm the optical identification of the three X-ray objects, and thereby the correctness of the accurate positions for 1E 2259+58.6 and 4U 0142+61 based on them. Based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.

  6. MEMS optical sensor

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an all-optical sensor utilizing effective index modulation of a waveguide and detection of a wavelength shift of reflected light and a force sensing system accommodating said optical sensor. One embodiment of the invention relates to a sensor system comprising...... at least one multimode light source, one or more optical sensors comprising a multimode sensor optical waveguide accommodating a distributed Bragg reflector, at least one transmitting optical waveguide for guiding light from said at least one light source to said one or more multimode sensor optical...... waveguides, a detector for measuring light reflected from said Bragg reflector in said one or more multimode sensor optical waveguides, and a data processor adapted for analyzing variations in the Bragg wavelength of at least one higher order mode of the reflected light....

  7. Effect of temperature on the optical and structural properties of hexadecylamine capped ZnS nanoparticles using Zinc(II) N-ethyl-N-phenyldithiocarbamate as single source precursor

    Energy Technology Data Exchange (ETDEWEB)

    Onwudiwe, Damian C., E-mail: dconwudiwe@webmail.co.za [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Strydom, Christien [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Oluwafemi, Oluwatobi S., E-mail: oluwafemi.oluwatobi@gmail.com [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag X1, Mthatha (South Africa); Songca, Sandile P. [Faculty of Science, Engineering and Technology, Walter Sisulu University, P.O. Box 19712, Tecoma, East London (South Africa)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► HDA-capped ZnS nanoparticles were synthesized via thermolysis of a single source precursor. ► Zinc(II) N-ethyl-N-phenyldithiocarbamate was used as the single source precursor. ► The growth temperature was varied to study the optical properties of the nanocrystals. ► Change in growth temperature affects the structural properties of the ZnS nanoparticles. ► Hexagonal wurtzite phase was obtained at lower temperatures while cubic sphalerite phase was obtained at higher growth temperatures. -- Abstract: Reported in this work is the synthesis of HDA (hexadecylamine)-capped ZnS nanoparticles by a single source route using Zinc(II) N-ethyl-N-phenyldithiocarbamate as a precursor. By varying the growth temperature, the temporal evolution of the optical properties and morphology of the nanocrystals were investigated. The as-synthesized nanoparticles were characterized using UV–vis absorption and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited quantum confinement in their optical properties with band edge emission at the early stage of the reaction. The XRD showed transition from hexagonal wurtzite phase to cubic sphalerite phase as the growth temperature increases. The TEM image showed that the particles are small and spherical in shape while the HRTEM image confirmed the crystalline nature of the material.

  8. Optic neuritis

    Science.gov (United States)

    Retro-bulbar neuritis; Multiple sclerosis - optic neuritis; Optic nerve - optic neuritis ... The exact cause of optic neuritis is unknown. The optic nerve carries visual information from your eye to the brain. The nerve can swell when ...

  9. RELATIVISTIC PLASMA AS THE DOMINANT SOURCE OF THE OPTICAL CONTINUUM EMISSION IN THE BROAD-LINE RADIO GALAXY 3C 120

    International Nuclear Information System (INIS)

    Leon-Tavares, J.; Lobanov, A. P.; Arshakian, T. G.; Chavushyan, V. H.; Doroshenko, V. T.; Sergeev, S. G.; Efimov, Y. S.; Nazarov, S. V.

    2010-01-01

    We report a relation between radio emission in the inner jet of the Seyfert galaxy 3C 120 and optical continuum emission in this galaxy. Combining the optical variability data with multi-epoch high-resolution very long baseline interferometry observations reveals that an optical flare rises when a superluminal component emerges into the jet, and its maxima is related to the passage of such component through the location of a stationary feature at a distance of ∼1.3 pc from the jet origin. This indicates that a significant fraction of the optical continuum produced in 3C 120 is non-thermal, and it can ionize material in a sub-relativistic wind or outflow. We discuss implications of this finding for the ionization and structure of the broad emission line region, as well as for the use of broad emission lines for determining black hole masses in radio-loud active galactic nucleus.

  10. Source Apportionment of PM2.5 Mass and Optical Attenuation Over an Ecologically Sensitive Zone in Central India by Positive Matrix Factorization

    Science.gov (United States)

    Nirmalkar, J.; Raman, R. S.

    2016-12-01

    Ambient PM2.5 samples (N=366) were collected over an ecologically sensitive zone (Van Vihar National Park) in Bhopal, Central India for two years (01 January, 2012 to 31 December, 2013). Samples were collected using three co-located Mini-Vol® samplers on Teflon, Nylon, and Quartz filter substrates. The aerosol was then chemically characterized for water-soluble inorganic ions, elements, and carbon fractions (elemental carbon and organic carbon) using ion chromatography, ED-XRF, and thermal-optical EC/OC analyzer, respectively. The optical attenuation (at 370 nm and 800 nm) of PM2.5 aerosols was also determined by optical transmissometry (OT-21). The application of Positive matrix factorization (PMF) to a combination of PM2.5 mass, its ions, elements, carbon fractions, and optical attenuation and its outcomes will be discussed.

  11. Fiber optic based optical tomography sensor for monitoring plasma uniformity

    International Nuclear Information System (INIS)

    Benck, Eric C.; Etemadi, Kasra

    2001-01-01

    A new type of fiber optic based optical tomography sensor has been developed for in situ monitoring of plasma uniformity. Optical tomography inverts optical emission measurements into the actual plasma distribution without assuming radial symmetry. The new sensor is designed to operate with only two small windows and acquire the necessary data in less than a second. Optical tomography is being tested on an ICP-GEC RF plasma source. Variations in plasma uniformity are measured as a function of different plasma conditions

  12. Noise and detection in ''optical'' modulation spectroscopy

    International Nuclear Information System (INIS)

    Montelatici, V.

    1975-01-01

    The measuring techniques suitable for ''optical'' modulation spectroscopy are analyzed and source of noise identified. The choice of optical detector is for photoelectrical devices. It is shown that the shot noise of phototubes is the most important noise source

  13. Enhanced radiation resistant fiber optics

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  14. Enhanced radiation resistant fiber optics

    Science.gov (United States)

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

    1993-11-30

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

  15. Noise-tolerance analysis for detection and reconstruction of absorbing inhomogeneities with diffuse optical tomography using single- and phase-correlated dual-source schemes

    International Nuclear Information System (INIS)

    Kanmani, B; Vasu, R M

    2007-01-01

    An iterative reconstruction procedure is used to invert intensity data from both single- and phase-correlated dual-source illuminations for absorption inhomogeneities. The Jacobian for the dual source is constructed by an algebraic addition of the Jacobians estimated for the two sources separately. By numerical simulations, it is shown that the dual-source scheme performs superior to the single-source system in regard to (i) noise tolerance in data and (ii) ability to reconstruct smaller and lower contrast objects. The quality of reconstructions from single-source data, as indicated by mean-square error at convergence, is markedly poorer compared to their dual-source counterpart, when noise in data was in excess of 2%. With fixed contrast and decreasing inhomogeneity diameter, our simulations showed that, for diameters below 7 mm, the dual-source scheme has a higher percentage contrast recovery compared to the single-source scheme. Similarly, the dual-source scheme reconstructs to a higher percentage contrast recovery from lower contrast inhomogeneity, in comparison to the single-source scheme

  16. Assessment of Open-Angle Glaucoma Peripapillary and Macular Choroidal Thickness Using Swept-Source Optical Coherence Tomography (SS-OCT.

    Directory of Open Access Journals (Sweden)

    Yong Ju Song

    Full Text Available To compare peripapillary and macular choroidal thickness (PCT and MCT between open-angle glaucoma (OAG and normal controls using swept-source optical coherence tomography (SS-OCT, and to evaluate global and localized relationships between choroidal thickness and various factors in OAG, also using SS-OCT.In this cross-sectional comparative study, 134 OAG patients and 73 normal controls were examined. PCT (global, 12 clock-hour sectors, MCT (global, six sectors were measured by SS-OCT. The difference in choroidal thickness between the OAG patients and the normal controls was analyzed. The relationships between choroidal thickness and various factors including age, sex, spherical equivalent (SE, axial length (AXL, central corneal thickness (CCT, intraocular pressure (IOP, peripapillary retinal nerve fiber layer thickness (pRNFLT, visual field mean deviation (MD, ganglion cell-inner plexiform layer thickness (GCIPLT, and disc area were analyzed by univariate and multivariate linear regression. Global and regional analyses were performed in 12 segments of the peripapillary circle and in six sectors of the macula.There were significant differences in global PCT and MCT between the OAG patients and the normal controls (115.22±41.17 vs. 138.89±44.70, P<0.001, (184.36±57.15 vs. 209.25±61.11, P = 0.004. The difference in global PCT remained, both after adjusting for age, AXL (117.08±3.45 vs. 135.47±4.70, P = 0.002 and also after adjusting for age, AXL, disc area (117.46±3.46 vs. 135.67±4.67, P = 0.002. But the difference in global MCT did not remain after adjusting for age, AXL, SE (188.18±4.46 vs. 202.25±6.08, P = 0.066. PCT showed significant differences between the groups in all of the 12 clock-hour sectors. These differences remained after adjusting for age, AXL and for age, AXL, disc area, with the exception of the 10 o'clock (o/c sector. MCT in six sectors showed differences between the two groups, but they did not remain after adjusting

  17. Doppler optical cardiogram gated 2D color flow imaging at 1000 fps and 4D in vivo visualization of embryonic heart at 45 fps on a swept source OCT system.

    Science.gov (United States)

    Mariampillai, Adrian; Standish, Beau A; Munce, Nigel R; Randall, Cristina; Liu, George; Jiang, James Y; Cable, Alex E; Vitkin, I A; Yang, Victor X D

    2007-02-19

    We report a Doppler optical cardiogram gating technique for increasing the effective frame rate of Doppler optical coherence tomography (DOCT) when imaging periodic motion as found in the cardiovascular system of embryos. This was accomplished with a Thorlabs swept-source DOCT system that simultaneously acquired and displayed structural and Doppler images at 12 frames per second (fps). The gating technique allowed for ultra-high speed visualization of the blood flow pattern in the developing hearts of African clawed frog embryos (Xenopus laevis) at up to 1000 fps. In addition, four-dimensional (three spatial dimensions + temporal) Doppler imaging at 45 fps was demonstrated using this gating technique, producing detailed visualization of the complex cardiac motion and hemodynamics in a beating heart.

  18. Swept-source optical coherence tomography powered by a 1.3-μm vertical cavity surface emitting laser enables 2.3-mm-deep brain imaging in mice in vivo

    Science.gov (United States)

    Choi, Woo June; Wang, Ruikang K.

    2015-10-01

    We report noninvasive, in vivo optical imaging deep within a mouse brain by swept-source optical coherence tomography (SS-OCT), enabled by a 1.3-μm vertical cavity surface emitting laser (VCSEL). VCSEL SS-OCT offers a constant signal sensitivity of 105 dB throughout an entire depth of 4.25 mm in air, ensuring an extended usable imaging depth range of more than 2 mm in turbid biological tissue. Using this approach, we show deep brain imaging in mice with an open-skull cranial window preparation, revealing intact mouse brain anatomy from the superficial cerebral cortex to the deep hippocampus. VCSEL SS-OCT would be applicable to small animal studies for the investigation of deep tissue compartments in living brains where diseases such as dementia and tumor can take their toll.

  19. Strategies to improve phase-stability of ultrafast swept source optical coherence tomography for single shot imaging of transient mechanical waves at 16 kHz frame rate

    Energy Technology Data Exchange (ETDEWEB)

    Song, Shaozhen; Wei, Wei; Hsieh, Bao-Yu; Pelivanov, Ivan; O' Donnell, Matthew [Department of Bioengineering, University of Washington, Seattle, Washington 98195 (United States); Shen, Tueng T.; Wang, Ruikang K., E-mail: wangrk@uw.edu [Department of Bioengineering, University of Washington, Seattle, Washington 98195 (United States); Department of Ophthalmology, University of Washington, Seattle, Washington 98104 (United States)

    2016-05-09

    We present single-shot phase-sensitive imaging of propagating mechanical waves within tissue, enabled by an ultrafast optical coherence tomography (OCT) system powered by a 1.628 MHz Fourier domain mode-locked (FDML) swept laser source. We propose a practical strategy for phase-sensitive measurement by comparing the phases between adjacent OCT B-scans, where the B-scan contains a number of A-scans equaling an integer number of FDML buffers. With this approach, we show that micro-strain fields can be mapped with ∼3.0 nm sensitivity at ∼16 000 fps. The system's capabilities are demonstrated on porcine cornea by imaging mechanical wave propagation launched by a pulsed UV laser beam, promising non-contact, real-time, and high-resolution optical coherence elastography.

  20. Circuit switched optical networks

    DEFF Research Database (Denmark)

    Kloch, Allan

    2003-01-01

    Some of the most important components required for enabling optical networking are investigated through both experiments and modelling. These all-optical components are the wavelength converter, the regenerator and the space switch. When these devices become "off-the-shelf" products, optical cross......, it is expected that the optical solution will offer an economical benefit for hight bit rate networks. This thesis begins with a discussion of the expected impact on communications systems from the rapidly growing IP traffic, which is expected to become the dominant source for traffic. IP traffic has some...... characteristics, which are best supported by an optical network. The interest for such an optical network is exemplified by the formation of the ACTS OPEN project which aim was to investigate the feasibility of an optical network covering Europe. Part of the work presented in this thesis is carried out within...

  1. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin

    2011-01-01

    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the λ = 2...

  2. Swept source optical coherence tomography for in vivo growth monitoring of capsicum annuum seeds treated with different NaCl concentrations

    Science.gov (United States)

    Ravichandran, Naresh Kumar; Wijesinghe, Ruchire Eranga; Lee, Seung-Yeol; Shirazi, Muhammad Faizan; Park, Kibeom; Jung, Hee-Young; Jeon, Mansik; Kim, Jeehyun

    2017-04-01

    In this study, Optical coherence tomography (OCT) is demonstrated as a plausible optical tool for in vivo detection of plant seeds and its morphological changes during growth. The experiment was carried out on Capsicum annuum seeds that were treated with different molar concentrations of NaCl to investigate the most optimal concentration for the seed growth. The monitoring process was carried out for 9 consecutive days. The in vivo 2D OCT images of the treated seeds were obtained and compared with seeds that were grown with sterile distilled water. The obtained results confirm the feasibility of using OCT for the proposed application. Normalized A-scan analysis method is utilized for supporting the concluded results.

  3. The optical spectra of 24 mu m galaxies in the cosmos field. I. Spitzer MIPS bright sources in the zCOSMOS-bright 10k catalog

    NARCIS (Netherlands)

    Caputi, K. I.; Lilly, S. J.; Aussel, H.; Sanders, D.; Frayer, D.; Le Fevre, O.; Renzini, A.; Zamorani, G.; Scodeggio, M.; Contini, T.; Scoville, N.; Carollo, C. M.; Hasinger, G.; Iovino, A.; Le Brun, V.; Le Floc'h, E.; Maier, C.; Mainieri, V.; Mignoli, M.; Salvato, M.; Schiminovich, D.; Silverman, J.; Surace, J.; Tasca, L.; Abbas, U.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Bottini, D.; Capak, P.; Cappi, A.; Cassata, P.; Cimatti, A.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Fumana, M.; Garilli, B.; Halliday, C.; Ilbert, O.; Kampczyk, P.; Kartaltepe, J.; Kneib, J. -P.; Knobel, C.; Kovac, K.; Lamareille, F.; Leauthaud, A.; Le Borgne, J. F.; Maccagni, D.; Marinoni, C.; McCracken, H.; Meneux, B.; Oesch, P.; Pello, R.; Perez-Montero, E.; Porciani, C.; Ricciardelli, E.; Scaramella, R.; Scarlata, C.; Tresse, L.; Vergani, D.; Walcher, J.; Zamojski, M.; Zucca, E.

    2008-01-01

    We study zCOSMOS-bright optical spectra for 609 Spitzer MIPS 24 mu m-selected galaxies with S-24 (mu m) > 0: 30 mJy and I <22.5 (AB mag) over 1.5 deg(2) of the COSMOS field. From emission-line diagnostics we find the following: (1) SFRs derived from the observed H alpha lambda 6563 and H beta lambda

  4. Optics, light and lasers

    CERN Document Server

    Meschede, Dieter

    2008-01-01

    Starting from the concepts of classical optics, Optics, Light and Lasers introduces in detail the phenomena of linear and nonlinear light matter interaction, the properties of modern laser sources, and the concepts of quantum optics. Several examples taken from the scope of modern research are provided to emphasize the relevance of optics in current developments within science and technology. The text has been written for newcomers to the topic and benefits from the author's ability to explain difficult sequences and effects in a straightforward and easily comprehensible way. To this second, c

  5. Optical gyroscope

    Science.gov (United States)

    Seifollahi, Alireza

    It is said that future of the world is based on space exploration which leads us to think more about low cost and light weight instruments. Cheap and sensitive instruments should be de-signed and replace the expensive ones. One of the required instruments in space ships is gyroscope controls the direction of space ship. In this article I am going to give an idea to use optical properties in a new gyroscope which will be cheaper as well as more sensitive in com-pare with most of the being used normal gyroscope nowadays. This instrument uses an optical system to measure the angular changes in the direction of a space craft movements in any of the three axels. Any movement, even very small one, will move a crystal bulb which is lashed by some narrow elastic bands in a fixed box surrounded by three optical sources and light meters. Light meters measure the attitude and the angel of changes in the light beams going through the bulb which is related to the amount of changes in the space craft directions. The system will be very sensitive even against movement around its access. As an electro digital device in connection to a Main Process Unit (MPU) it can be used in Stability Augmentation System (SAS) in a space ship. The sensitivity rate of the instrument will be based on the quality and sensitivity of the light meters.

  6. Source of ultra-short laser pulses at 1,55μm in vertical-external-cavity for linear optical sampling applications

    International Nuclear Information System (INIS)

    Khadour, A.

    2009-12-01

    The objectives of this thesis were, in a first step, to develop and implement VECSEL structures containing an active zone formed by GaAlInAs/InP quantum wells located at the anti-nodes of the resonant electric field, positioned on a Bragg mirror, all this being bonded to a substrate of good thermal conductivity. For this, we have designed structures optimizing the evacuation of heat generated in the active zone. This has greatly improved the VECSEL performances, especially their output power. The VECSEL performances were evaluated in a simple cavity with two mirrors (plane-concave). The second point was to develop and implement SESAM structures which, owing to their nonlinear characteristics, would allow a passively mode-locked laser operation. The structures contained InGaAsN/GaAs quantum wells. The studied parameters were the number of quantum wells, and the resonant or anti-resonant behavior of the structure. The linear and nonlinear optical characterizations were used to optimize the SESAM structure and estimate their performances. Finally, the compatibility between the VECSEL and SESAM structures, in terms of modulation depth and resonance wavelength, made it possible to obtain the passive mode locking operation. The obtained pulses show two different behaviors depending on the dispersion properties of the structures. With low dispersion, we have made the first demonstration of a passively mode-locked VECSEL at 1550 nm, operating at room temperature. An all-optical sampling device implementing the linear optical sampling technique using short laser pulses has been realized and tested. This device will allow displaying eye diagrams and constellation diagrams with an expected sensitivity around -20 dBm of average power. Testing the device allowed to visualize the acquisition of very high repetition rate signals (40 Gb/s). (author)

  7. Study of the use of an electric discharge for hollow cathodes used as optical excitation sources in the spectrographic measurement of fluorine in thorium, uranium and plutonium

    International Nuclear Information System (INIS)

    Bufpereau, M.; Crehange, G.; Poublan, J.

    1964-01-01

    Previous works and phenomena concerned with a hollow cathode excitation are reviewed. Experiments aimed specially on the determination of the best conditions for an analysis of fluorine in oxides-metals and solutions. In that purpose, several factors have been pointed out. One started some researches about others elements that fluorine. Carrying fluorine into discharge and excitation have been more specially studied. A quantitative analysis method is given. The analysis limit is 45 ppm about but the detection limit is 5 ppm about. As a conclusion, various ways for optical excitation of fluorine are reviewed as other analytical possibilities a hollow cathode discharge offers. (authors) [fr

  8. Field guide to nonlinear optics

    CERN Document Server

    Powers, Peter E

    2013-01-01

    Optomechanics is a field of mechanics that addresses the specific design challenges associated with optical systems. This [i]Field Guide [/i]describes how to mount optical components, as well as how to analyze a given design. It is intended for practicing optical and mechanical engineers whose work requires knowledge in both optics and mechanics. This Field Guide is designed for those looking for a condensed and concise source of key concepts, equations, and techniques for nonlinear optics. Topics covered include technologically important effects, recent developments in nonlinear optics

  9. Nonlinear optics

    International Nuclear Information System (INIS)

    Boyd, R.W.

    1992-01-01

    Nonlinear optics is the study of the interaction of intense laser light with matter. This book is a textbook on nonlinear optics at the level of a beginning graduate student. The intent of the book is to provide an introduction to the field of nonlinear optics that stresses fundamental concepts and that enables the student to go on to perform independent research in this field. This book covers the areas of nonlinear optics, quantum optics, quantum electronics, laser physics, electrooptics, and modern optics

  10. Physical optics

    International Nuclear Information System (INIS)

    Kim Il Gon; Lee, Seong Su; Jang, Gi Wan

    2012-07-01

    This book indicates physical optics with properties and transmission of light, mathematical expression of wave like harmonic wave and cylindrical wave, electromagnetic theory and light, transmission of light with Fermat principle and Fresnel equation, geometrical optics I, geometrical optics II, optical instrument such as stops, glasses and camera, polarized light like double refraction by polarized light, interference, interference by multiple reflections, diffraction, solid optics, crystal optics such as Faraday rotation and Kerr effect and measurement of light. Each chapter has an exercise.

  11. Physical optics

    Energy Technology Data Exchange (ETDEWEB)

    Kim Il Gon; Lee, Seong Su; Jang, Gi Wan

    2012-07-15

    This book indicates physical optics with properties and transmission of light, mathematical expression of wave like harmonic wave and cylindrical wave, electromagnetic theory and light, transmission of light with Fermat principle and Fresnel equation, geometrical optics I, geometrical optics II, optical instrument such as stops, glasses and camera, polarized light like double refraction by polarized light, interference, interference by multiple reflections, diffraction, solid optics, crystal optics such as Faraday rotation and Kerr effect and measurement of light. Each chapter has an exercise.

  12. Cross-validation of theoretically quantified fiber continuum generation and absolute pulse measurement by MIIPS for a broadband coherently controlled optical source

    DEFF Research Database (Denmark)

    Tu, H.; Liu, Y.; Lægsgaard, Jesper

    2012-01-01

    source with the MIIPS-integrated pulse shaper produces compressed transform-limited 9.6 fs (FWHM) pulses or arbitrarily shaped pulses at a central wavelength of 1020 nm, an average power over 100 mW, and a repetition rate of 76 MHz. In comparison to the 229-fs pump laser pulses that generate the fiber......The predicted spectral phase of a fiber continuum pulsed source rigorously quantified by the scalar generalized nonlinear Schrödinger equation is found to be in excellent agreement with that measured by multiphoton intrapulse interference phase scan (MIIPS) with background subtraction. This cross......-validation confirms the absolute pulse measurement by MIIPS and the transform-limited compression of the fiber continuum pulses by the pulse shaper performing the MIIPS measurement, and permits the subsequent coherent control on the fiber continuum pulses by this pulse shaper. The combination of the fiber continuum...

  13. Quantum optics

    National Research Council Canada - National Science Library

    Agarwal, G. S

    2013-01-01

    .... Focusing on applications of quantum optics, the textbook covers recent developments such as engineering of quantum states, quantum optics on a chip, nano-mechanical mirrors, quantum entanglement...

  14. Online coupling of pure O_2 thermo-optical methods – "1"4C AMS for source apportionment of carbonaceous aerosols

    International Nuclear Information System (INIS)

    Agrios, Konstantinos; Salazar, Gary; Zhang, Yan-Lin; Uglietti, Chiara; Battaglia, Michael; Luginbühl, Marc; Ciobanu, Viorela Gabriela; Vonwiller, Matthias; Szidat, Sönke

    2015-01-01

    This paper reports on novel separation methods developed for the direct determination of "1"4C in organic carbon (OC) and elemental carbon (EC), two sub-fractions of total carbon (TC) of atmospheric air particulate matter. Until recently, separation of OC and EC has been performed off-line by manual and time-consuming techniques that relied on the collection of massive CO_2 fractions. We present here two on-line hyphenated techniques between a Sunset OC/EC analyzer and a MICADAS (MIni radioCArbon DAting System) accelerator mass spectrometer (AMS) equipped with a gas ion source. The first implementation facilitates the direct measurement in the low sample size range (<10 μg C) with high throughput on a routine basis, while the second explores the potential for a continuous-flow real-time CO_2 gas feed into the ion source. The performance achieved with reference materials and real atmospheric samples will be discussed to draw conclusions on the improvement offered in the field of "1"4C aerosol source apportionment.

  15. Online coupling of pure O{sub 2} thermo-optical methods – {sup 14}C AMS for source apportionment of carbonaceous aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Agrios, Konstantinos [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Paul Scherrer Institute, Villigen (Switzerland); Salazar, Gary [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Zhang, Yan-Lin; Uglietti, Chiara [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Paul Scherrer Institute, Villigen (Switzerland); Battaglia, Michael [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Luginbühl, Marc [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Ciobanu, Viorela Gabriela [Paul Scherrer Institute, Villigen (Switzerland); Vonwiller, Matthias [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Paul Scherrer Institute, Villigen (Switzerland); Szidat, Sönke, E-mail: szidat@dcb.unibe.ch [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland)

    2015-10-15

    This paper reports on novel separation methods developed for the direct determination of {sup 14}C in organic carbon (OC) and elemental carbon (EC), two sub-fractions of total carbon (TC) of atmospheric air particulate matter. Until recently, separation of OC and EC has been performed off-line by manual and time-consuming techniques that relied on the collection of massive CO{sub 2} fractions. We present here two on-line hyphenated techniques between a Sunset OC/EC analyzer and a MICADAS (MIni radioCArbon DAting System) accelerator mass spectrometer (AMS) equipped with a gas ion source. The first implementation facilitates the direct measurement in the low sample size range (<10 μg C) with high throughput on a routine basis, while the second explores the potential for a continuous-flow real-time CO{sub 2} gas feed into the ion source. The performance achieved with reference materials and real atmospheric samples will be discussed to draw conclusions on the improvement offered in the field of {sup 14}C aerosol source apportionment.

  16. Interferometry using undulator sources

    International Nuclear Information System (INIS)

    Beguiristain, R.; Goldberg, K.A.; Tejnil, E.; Bokor, J.; Medecki, H.; Attwood, D.T.; Jackson, K.

    1996-01-01

    Optical systems for extreme ultraviolet (EUV) lithography need to use optical components with subnanometer surface figure error tolerances to achieve diffraction-limited performance [M.D. Himel, in Soft X-Ray Projection Lithography, A.M. Hawryluk and R.H. Stulen, eds. (OSA, Washington, D.C., 1993), 18, 1089, and D. Attwood et al., Appl. Opt. 32, 7022 (1993)]. Also, multilayer-coated optics require at-wavelength wavefront measurement to characterize phase effects that cannot be measured by conventional optical interferometry. Furthermore, EUV optical systems will additionally require final testing and alignment at the operational wavelength for adjustment and reduction of the cumulative optical surface errors. Therefore, at-wavelength interferometric measurement of EUV optics will be the necessary metrology tool for the successful development of optics for EUV lithography. An EUV point diffraction interferometer (PDI) has been developed at the Center for X-Ray Optics (CXRO) and has been already in operation for a year [K. Goldberg et al., in Extreme Ultra Lithography, D.T. Attwood and F. Zernike, eds. (OSA, Washington, D.C., 1994), K. Goldberg et al., Proc. SPIE 2437, to be published, and K. Goldberg et al., J. Vac. Sci. Technol. B 13, 2923 (1995)] using an undulator radiation source and coherent optics beamline at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. An overview of the PDI interferometer and some EUV wavefront measurements obtained with this instrument will be presented. In addition, future developments planned for EUV interferometry at CXRO towards the measurement of actual EUV lithography optics will be shown. copyright 1996 American Institute of Physics

  17. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

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

    2010-01-01

    The optical fiber based supercontinuum source has recently become a significant scientific and commercial success, with applications ranging from frequency comb production to advanced medical imaging. This one-of-a-kind book explains the theory of fiber supercontinuum broadening, describes......, provides a background to the associated nonlinear optical processes, treats the generation mechanisms from continuous wave to femtosecond pulse pump regimes and highlights the diverse applications. A full discussion of numerical methods and comprehensive computer code are also provided, enabling readers...

  18. Comparative Study of Anterior Eye Segment Measurements with Spectral Swept-Source and Time-Domain Optical Coherence Tomography in Eyes with Corneal Dystrophies.

    Science.gov (United States)

    Nowinska, Anna K; Teper, Sławomir J; Janiszewska, Dominika A; Lyssek-Boron, Anita; Dobrowolski, Dariusz; Koprowski, Robert; Wylegala, Edward

    2015-01-01

    To compare anterior eye segment measurements and morphology obtained with two optical coherence tomography systems (TD OCT, SS OCT) in eyes with corneal dystrophies (CDs). Fifty healthy volunteers (50 eyes) and 54 patients (96 eyes) diagnosed with CD (epithelial basement membrane dystrophy, EBMD = 12 eyes; Thiel-Behnke CD = 6 eyes; lattice CD TGFBI type = 15 eyes; granular CD type 1 = 7 eyes, granular CD type 2 = 2 eyes; macular CD = 23 eyes; and Fuchs endothelial CD = 31 eyes) were recruited for the study. Automated and manual central corneal thickness (aCCT, mCCT), anterior chamber depth (ACD), and nasal and temporal trabecular iris angle (nTIA, tTIA) were measured and compared with Bland-Altman plots. Good agreement between the TD and SS OCT measurements was demonstrated for mCCT and aCCT in normal individuals and for mCCT in the CDs group. The ACD, nTIA, and tTIA measurements differed significantly in both groups. TBCD, LCD, and FECD caused increased CCT. MCD caused significant corneal thinning. FECD affected all analyzed parameters. Better agreement between SS OCT and TD OCT measurements was demonstrated in normal individuals compared to the CDs group. OCT provides comprehensive corneal deposits analysis and demonstrates the association of CD with CCT, ACD, and TIA measurements.

  19. Comparative Study of Anterior Eye Segment Measurements with Spectral Swept-Source and Time-Domain Optical Coherence Tomography in Eyes with Corneal Dystrophies

    Directory of Open Access Journals (Sweden)

    Anna K. Nowinska

    2015-01-01

    Full Text Available Purpose. To compare anterior eye segment measurements and morphology obtained with two optical coherence tomography systems (TD OCT, SS OCT in eyes with corneal dystrophies (CDs. Methods. Fifty healthy volunteers (50 eyes and 54 patients (96 eyes diagnosed with CD (epithelial basement membrane dystrophy, EBMD = 12 eyes; Thiel-Behnke CD = 6 eyes; lattice CD TGFBI type = 15 eyes; granular CD type 1 = 7 eyes, granular CD type 2 = 2 eyes; macular CD = 23 eyes; and Fuchs endothelial CD = 31 eyes were recruited for the study. Automated and manual central corneal thickness (aCCT, mCCT, anterior chamber depth (ACD, and nasal and temporal trabecular iris angle (nTIA, tTIA were measured and compared with Bland-Altman plots. Results. Good agreement between the TD and SS OCT measurements was demonstrated for mCCT and aCCT in normal individuals and for mCCT in the CDs group. The ACD, nTIA, and tTIA measurements differed significantly in both groups. TBCD, LCD, and FECD caused increased CCT. MCD caused significant corneal thinning. FECD affected all analyzed parameters. Conclusions. Better agreement between SS OCT and TD OCT measurements was demonstrated in normal individuals compared to the CDs group. OCT provides comprehensive corneal deposits analysis and demonstrates the association of CD with CCT, ACD, and TIA measurements.

  20. Long-range, wide-field swept-source optical coherence tomography with GPU accelerated digital lock-in Doppler vibrography for real-time, in vivo middle ear diagnostics.

    Science.gov (United States)

    MacDougall, Dan; Farrell, Joshua; Brown, Jeremy; Bance, Manohar; Adamson, Robert

    2016-11-01

    We present the design, implementation and validation of a swept-source optical coherence tomography (OCT) system for real-time imaging of the human middle ear in live patients. Our system consists of a highly phase-stable Vernier-tuned distributed Bragg-reflector laser along with a real-time processing engine implemented on a graphics processing unit. We use the system to demonstrate, for the first time in live subjects, real-time Doppler measurements of middle ear vibration in response to sound, video rate 2D B-mode imaging of the middle ear and 3D volumetric B-mode imaging. All measurements were performed non-invasively through the intact tympanic membrane demonstrating that the technology is readily translatable to the clinic.

  1. Noise Characterization of Devices for Optical Computing

    National Research Council Canada - National Science Library

    Walkup, John

    1998-01-01

    The major objective of the research effort is to investigate the noise characteristics of advanced optical Sources, spatial light modulators, and other devices which are candidates for applications in optical computers...

  2. Illusion induced overlapped optics.

    Science.gov (United States)

    Zang, XiaoFei; Shi, Cheng; Li, Zhou; Chen, Lin; Cai, Bin; Zhu, YiMing; Zhu, HaiBin

    2014-01-13

    The traditional transformation-based cloak seems like it can only hide objects by bending the incident electromagnetic waves around the hidden region. In this paper, we prove that invisible cloaks can be applied to realize the overlapped optics. No matter how many in-phase point sources are located in the hidden region, all of them can overlap each other (this can be considered as illusion effect), leading to the perfect optical interference effect. In addition, a singular parameter-independent cloak is also designed to obtain quasi-overlapped optics. Even more amazing of overlapped optics is that if N identical separated in-phase point sources covered with the illusion media, the total power outside the transformation region is N2I0 (not NI0) (I0 is the power of just one point source, and N is the number point sources), which seems violating the law of conservation of energy. A theoretical model based on interference effect is proposed to interpret the total power of these two kinds of overlapped optics effects. Our investigation may have wide applications in high power coherent laser beams, and multiple laser diodes, and so on.

  3. Photonic crystal light source

    Science.gov (United States)

    Fleming, James G [Albuquerque, NM; Lin, Shawn-Yu [Albuquerque, NM; Bur, James A [Corrales, NM

    2004-07-27

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  4. Optical Computing

    OpenAIRE

    Woods, Damien; Naughton, Thomas J.

    2008-01-01

    We consider optical computers that encode data using images and compute by transforming such images. We give an overview of a number of such optical computing architectures, including descriptions of the type of hardware commonly used in optical computing, as well as some of the computational efficiencies of optical devices. We go on to discuss optical computing from the point of view of computational complexity theory, with the aim of putting some old, and some very recent, re...

  5. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Ohsuka, Shinji, E-mail: ohsuka@crl.hpk.co.jp [Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu-City, 434-8601 (Japan); The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu-cho, Nishi-ku, Hamamatsu-City, 431-1202 (Japan); Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro [Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu-City, 434-8601 (Japan); Nakano, Tomoyasu [Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu-City, 434-8601 (Japan); Ray-Focus Co. Ltd., 6009 Shinpara, Hamakita-ku, Hamamatsu-City, 434-0003 (Japan); Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao [Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2014-09-15

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  6. Efficient three-dimensional resist profile-driven source mask optimization optical proximity correction based on Abbe-principal component analysis and Sylvester equation

    Science.gov (United States)

    Lin, Pei-Chun; Yu, Chun-Chang; Chen, Charlie Chung-Ping

    2015-01-01

    As one of the critical stages of a very large scale integration fabrication process, postexposure bake (PEB) plays a crucial role in determining the final three-dimensional (3-D) profiles and lessening the standing wave effects. However, the full 3-D chemically amplified resist simulation is not widely adopted during the postlayout optimization due to the long run-time and huge memory usage. An efficient simulation method is proposed to simulate the PEB while considering standing wave effects and resolution enhancement techniques, such as source mask optimization and subresolution assist features based on the Sylvester equation and Abbe-principal component analysis method. Simulation results show that our algorithm is 20× faster than the conventional Gaussian convolution method.

  7. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source.

    Science.gov (United States)

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2014-09-01

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  8. Synergetic effect of green tea on polymer gel dosimeter and determination of optimal wavelength to choose light source for optical computed tomography

    Directory of Open Access Journals (Sweden)

    Sathiya Raj

    2016-03-01

    Full Text Available Purpose: The ultimate aim of this study is to observe the effect of Green tea as a co-antioxidant in PAGAT gel dosimeter and evaluate the appropriate light source for scanning the PAGAT and NIPAM polymer gel.Methods: Both PAGAT (Poly Acrylamide Gelatin Tetrakis hydroxyl phosphonium chloride and NIPAM (N-Isopropyl acrylamide gel were prepared in normoxic condition. The green tea extract (GTE was prepared and tested only on PAGAT. Co-60 teletherapy machine has been used for irradiation purpose, and the gel samples were scanned using UV-Visible spectrophotometer. Water equivalency of the gel has been tested in terms of their electron density, effective atomic number and Ratio of oxygen and hydrogen (O/H. We have used NIST XCOM database to test the water equivalency.Results: In this study we found that the GTE added to the gel do not respond to the given doses. By adding sugar we can enhance the sensitivity of the gel. Further investigations are required to use Green tea as a co antioxidant concentration of THPC (Tetrakis hydroxymethyl phosphonium chloride. The optimal wavelength with different region for scanning the PAGAT is 450 to 480 nm (Blue region, for NIPAM it is 540 nm and 570 nm (Green and yellow region. The PAGAT and NIPAM showed better sensitivity at 510 nm. Both gels have their effective atomic number closer to water (NIPAM-7.2, PAGAT-7.379.Conclusion: As per our results, we concluded that GTE alone is not an effective co-antioxidant for polymer gels. When the GTE is combined with sugar and THPC, it protects the gel from pre-polymerization. This study strongly suggests that the blue light is an optimal source for scanning the PAGAT and green to yellow light for NIPAM gel. Though both gels were considered as water equivalent, the PAGAT is equivalent to water and the temporal stability of this gel is higher than NIPAM.

  9. Engineering Optics

    CERN Document Server

    Iizuka, Keigo

    2008-01-01

    Engineering Optics is a book for students who want to apply their knowledge of optics to engineering problems, as well as for engineering students who want to acquire the basic principles of optics. It covers such important topics as optical signal processing, holography, tomography, holographic radars, fiber optical communication, electro- and acousto-optic devices, and integrated optics (including optical bistability). As a basis for understanding these topics, the first few chapters give easy-to-follow explanations of diffraction theory, Fourier transforms, and geometrical optics. Practical examples, such as the video disk, the Fresnel zone plate, and many more, appear throughout the text, together with numerous solved exercises. There is an entirely new section in this updated edition on 3-D imaging.

  10. Effect of a dam on the optical properties of different-sized fractions of dissolved organic matter in a mid-subtropical drinking water source reservoir.

    Science.gov (United States)

    Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong

    2017-11-15

    The presence of a dam on a river is believed to have a key role in affecting changes in the components of the chromophoric dissolved organic matter (CDOM) in reservoirs. However, questions remain about the mechanisms that control these changes. In this study, we used tangential ultrafiltration, fluorescence spectrum and phytoplankton cell density detection to explore the impacts of a dam on the CDOM components in the Shanzai Reservoir, a source of drinking water. The results demonstrated each CDOM size fraction comprised two main components, namely C1 (protein-like substance) and C2 (humic-like substance). The C1 content had a higher value in areas with slow flow than in the normal river channel, while the C2 contents were generally stable in the flow direction. The topography of the reservoir site affected the structure of the CDOM components based on changes in the hydraulic conditions caused by the dam. The variations in the CDOM components, hydraulic parameters and fluorescence indices in the river flow direction indicated that the contribution of the phytoplankton to the CDOM content increased as the distance to the dam decreased, phytoplankton metabolism enhanced C1 content of the 1-10kDa molecular weights range fraction. Further, the contributions of different phytoplankton biomass to C1 proved that the dam changed the hydraulic conditions, had secondary effects on the metabolism of the phytoplankton, and resulted in changes in the structure of the CDOM components. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Metal-coated semiconductor nanostructures and simulation of photon extraction and coupling to optical fibers for a solid-state single-photon source

    International Nuclear Information System (INIS)

    Suemune, Ikuo; Nakajima, Hideaki; Liu, Xiangming; Odashima, Satoru; Asano, Tomoya; Iijima, Hitoshi; Huh, Jae-Hoon; Idutsu, Yasuhiro; Sasakura, Hirotaka; Kumano, Hidekazu

    2013-01-01

    We have realized metal-coated semiconductor nanostructures for a stable and efficient single-photon source (SPS) and demonstrated improved single-photon extraction efficiency by the selection of metals and nanostructures. We demonstrate with finite-difference time-domain (FDTD) simulations that inclination of a pillar sidewall, which changes the structure to a nanocone, is effective in improving the photon extraction efficiency. We demonstrate how such nanocone structures with inclined sidewalls are fabricated with reactive ion etching. With the optimized design, a photon extraction efficiency to outer airside as high as ∼97% generated from a quantum dot in a nanocone structure is simulated, which is the important step in realizing SPS on-demand operations. We have also examined the direct contact of such a metal-embedded nanocone structure with a single-mode fiber facet as a simple and practical method for preparing fiber-coupled SPS and demonstrated practical coupling efficiencies of ∼16% with FDTD simulation. (paper)

  12. Sources, compositions, and optical properties of humic-like substances in Beijing during the 2014 APEC summit: Results from dual carbon isotope and Fourier-transform ion cyclotron resonance mass spectrometry analyses.

    Science.gov (United States)

    Mo, Yangzhi; Li, Jun; Jiang, Bin; Su, Tao; Geng, Xiaofei; Liu, Junwen; Jiang, Haoyu; Shen, Chengde; Ding, Ping; Zhong, Guangcai; Cheng, Zhineng; Liao, Yuhong; Tian, Chongguo; Chen, Yingjun; Zhang, Gan

    2018-08-01

    Humic-like substances (HULIS) are a class of high molecular weight, light-absorbing compounds that are highly related to brown carbon (BrC). In this study, the sources and compositions of HULIS isolated from fine particles collected in Beijing, China during the 2014 Asia-Pacific Economic Cooperation (APEC) summit were characterized based on carbon isotope ( 13 C and 14 C) and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses, respectively. HULIS were the main light-absorbing components of water-soluble organic carbon (WSOC), accounting for 80.2 ± 6.1% of the WSOC absorption capacity at 365 nm. The carbon isotope data showed that HULIS had a lower non-fossil contribution (53 ± 4%) and were less enriched with 13 C (-24.2 ± 0.6‰) relative to non-HULIS (62 ± 8% and -20.8 ± 0.3‰, respectively). The higher relative intensity fraction of sulfur-containing compounds in HULIS before and after APEC was attributed to higher sulfur dioxide levels emitted from fossil fuel combustion, whereas the higher fraction of nitrogen-containing compounds during APEC may have been due to the relatively greater contribution of non-fossil compounds or the influence of nitrate radical chemistry. The results of investigating the relationships among the sources, elemental compositions, and optical properties of HULIS demonstrated that the light absorption of HULIS appeared to increase with increasing unsaturation degree, but decrease with increasing oxidation level. The unsaturation of HULIS was affected by both sources and aging level. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Electron optics

    CERN Document Server

    Grivet, Pierre; Bertein, F; Castaing, R; Gauzit, M; Septier, Albert L

    1972-01-01

    Electron Optics, Second English Edition, Part I: Optics is a 10-chapter book that begins by elucidating the fundamental features and basic techniques of electron optics, as well as the distribution of potential and field in electrostatic lenses. This book then explains the field distribution in magnetic lenses; the optical properties of electrostatic and magnetic lenses; and the similarities and differences between glass optics and electron optics. Subsequent chapters focus on lens defects; some electrostatic lenses and triode guns; and magnetic lens models. The strong focusing lenses and pris

  14. Comparison of optical properties of chromophoric dissolved organic matter (CDOM) in alpine lakes above or below the tree line: insights into sources of CDOM.

    Science.gov (United States)

    Su, Yaling; Chen, Feizhou; Liu, Zhengwen

    2015-05-01

    Here we investigated absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) in 15 alpine lakes located below or above the tree line to determine its source and composition. The results indicate that the concentrations of CDOM in below-tree-line lakes are significantly higher than in above-tree-line lakes, as evidenced from the absorption coefficients of a250 and a365. The intensities of the protein-like and humic-like fluorescence in below-tree-line lakes are higher than in above-tree-line lakes as well. Three fluorescent components were identified using parallel factor analysis (PARAFAC) modelling. Component 1 is probably associated with biological degradation of terrestrial humic component. The terrestrial humic-like component 2 is only found in below-tree-line lakes. The protein-like or phenolic component 3 is dominant in above-tree-line lakes, which is probably more derived from autochthonous origin. In this study, (1) higher a250/a365 and S275-295 values indicate smaller molecular weights of CDOM in above-tree-line lakes than in below-tree-line lakes, and smaller molecular weights at the surface than at 2.0 m depth; (2) SUVA254 and FI255 results provide evidence of lower percent aromaticity of CDOM in above-tree-line lakes; and (3) FI310 and FI370 suggest a strong allochthonous origin at the surface in below-tree-line lakes, and more contribution from autochthonous biological and aquatic bacterial origin in above-tree-line lakes.

  15. Time domain optical spectrometry with fiber optic waveguides

    International Nuclear Information System (INIS)

    Whitten, W.B.

    1983-01-01

    Spectrometers which use optical fibers to obtain time domain spectral dispersion are reviewed. Pulse transmission through fiber optic waveguides is discussed and the basic requirements for sources and detectors are given. Multiplex spectrometry and time-of-flight spectrometry are then discussed. Resolution, fiber requirements, instrumentation and specific spectrometers are presented

  16. Optical Observations of X-ray Bright, Optically Normal Galaxies

    Science.gov (United States)

    Sadun, Alberto C.; Aryan, N. S.; Ghosh, K. K.

    2007-05-01

    X-ray bright, optically normal galaxies (XBONGs) are galaxies that seem to have normal spectra and morphology, but are relatively bright x-ray sources. The large ratio of the x-ray to optical emission suggests that some activity, similar to that of active galactic nuclei (AGN), is occurring. Since the galaxies do not show any obvious sign of nuclear activity in their optical spectra, one possible explanation is that these galaxies do not have an optically thick accretion disk at small radii, as previously assumed. Previous data for NGC 7626 classifies it as an XBONG, and so we are studying optical features of this galaxy in order to determine better its features. After confirming an x-ray jet, we are now comparing this to optical features that we have found, including warped dust lanes and a possible optical jet.

  17. Optical networks a practical perspective

    CERN Document Server

    Ramaswami, Rajiv

    2001-01-01

    This fully updated and expanded second edition of Optical Networks: A Practical Perspective succeeds the first as the authoritative source for information on optical networking technologies and techniques. Written by two of the field's most respected individuals, it covers componentry and transmission in detail but also emphasizes the practical networking issues that affect organizations as they evaluate, deploy, or develop optical solutions. This book captures all the hard-to-find information on architecture, control and management, and other communications topics that

  18. Optical tweezers principles and applications

    CERN Document Server

    Jones, Philip; Volpe, Giovanni

    2015-01-01

    Combining state-of-the-art research with a strong pedagogic approach, this text provides a detailed and complete guide to the theory, practice and applications of optical tweezers. In-depth derivation of the theory of optical trapping and numerical modelling of optical forces are supported by a complete step-by-step design and construction guide for building optical tweezers, with detailed tutorials on collecting and analysing data. Also included are comprehensive reviews of optical tweezers research in fields ranging from cell biology to quantum physics. Featuring numerous exercises and problems throughout, this is an ideal self-contained learning package for advanced lecture and laboratory courses, and an invaluable guide to practitioners wanting to enter the field of optical manipulation. The text is supplemented by www.opticaltweezers.org, a forum for discussion and a source of additional material including free-to-download, customisable research-grade software (OTS) for calculation of optical forces, dig...

  19. Optical wear monitoring

    Science.gov (United States)

    Kidane, Getnet S; Desilva, Upul P.; He, Chengli; Ulerich, Nancy H.

    2016-07-26

    A gas turbine includes first and second parts having outer surfaces located adjacent to each other to create an interface where wear occurs. A wear probe is provided for monitoring wear of the outer surface of the first part, and includes an optical guide having first and second ends, wherein the first end is configured to be located flush with the outer surface of the first part. A fiber bundle includes first and second ends, the first end being located proximate to the second end of the optical guide. The fiber bundle includes a transmit fiber bundle comprising a first plurality of optical fibers coupled to a light source, and a receive fiber bundle coupled to a light detector and configured to detect reflected light. A processor is configured to determine a length of the optical guide based on the detected reflected light.

  20. Photoacoustic Point Source

    International Nuclear Information System (INIS)

    Calasso, Irio G.; Craig, Walter; Diebold, Gerald J.

    2001-01-01

    We investigate the photoacoustic effect generated by heat deposition at a point in space in an inviscid fluid. Delta-function and long Gaussian optical pulses are used as sources in the wave equation for the displacement potential to determine the fluid motion. The linear sound-generation mechanism gives bipolar photoacoustic waves, whereas the nonlinear mechanism produces asymmetric tripolar waves. The salient features of the photoacoustic point source are that rapid heat deposition and nonlinear thermal expansion dominate the production of ultrasound

  1. A review of polarized ion sources

    International Nuclear Information System (INIS)

    Schmor, P.W.

    1995-06-01

    The two main types of polarized ion sources in use on accelerators today are the Atomic Beam Polarized Ion Source (ABIS) source and the Optically Pumped Polarized Ion Source (OPPIS). Both types can provide beams of nuclearly polarized light ions which are either positively or negatively charged. Heavy ion polarized ion sources for accelerators are being developed. (author). 35 refs., 1 tab

  2. Optical properties of nanoparticles

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    At the NBI I am involved in projects relating to optical properties of metallic nanoparticles in particular with respect to plasmonic heating with direct applications to photothermal cancer therapy. For this purpose we have developed heating assays that can be used to measure the heating of any...... nanoscopic heat source like an irradiated nanoparticle...

  3. Fluidic optics

    Science.gov (United States)

    Whitesides, George M.; Tang, Sindy K. Y.

    2006-09-01

    Fluidic optics is a new class of optical system with real-time tunability and reconfigurability enabled by the introduction of fluidic components into the optical path. We describe the design, fabrication, operation of a number of fluidic optical systems, and focus on three devices, liquid-core/liquid-cladding (L2) waveguides, microfluidic dye lasers, and diffraction gratings based on flowing, crystalline lattices of bubbles, to demonstrate the integration of microfluidics and optics. We fabricate these devices in poly(dimethylsiloxane) (PDMS) with soft-lithographic techniques. They are simple to construct, and readily integrable with microanalytical or lab-on-a-chip systems.

  4. Optical fibres

    CERN Document Server

    Geisler, J; Boutruche, J P

    1986-01-01

    Optical Fibers covers numerous research works on the significant advances in optical fibers, with particular emphasis on their application.This text is composed of three parts encompassing 15 chapters. The first part deals with the manufacture of optical fibers and the materials used in their production. The second part describes optical-fiber connectors, terminals and branches. The third part is concerned with the major optoelectronic components encountered in optical-communication systems.This book will be of value to research scientists, engineers, and patent workers.

  5. Atom optics

    International Nuclear Information System (INIS)

    Balykin, V. I.; Jhe, W.

    1999-01-01

    Atom optics, in analogy to neutron and electron optics, deals with the realization of as a traditional elements, such as lenes, mirrors, beam splitters and atom interferometers, as well as a new 'dissipative' elements such as a slower and a cooler, which have no analogy in an another types of optics. Atom optics made the development of atom interferometer with high sensitivity for measurement of acceleration and rotational possible. The practical interest in atom optics lies in the opportunities to create atom microprobe with atom-size resolution and minimum damage of investigated objects. (Cho, G. S.)

  6. Optical interconnects

    CERN Document Server

    Chen, Ray T

    2006-01-01

    This book describes fully embedded board level optical interconnect in detail including the fabrication of the thin-film VCSEL array, its characterization, thermal management, the fabrication of optical interconnection layer, and the integration of devices on a flexible waveguide film. All the optical components are buried within electrical PCB layers in a fully embedded board level optical interconnect. Therefore, we can save foot prints on the top real estate of the PCB and relieve packaging difficulty reduced by separating fabrication processes. To realize fully embedded board level optical

  7. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

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

  8. Two mode optical fiber in space optics communication

    Science.gov (United States)

    Hampl, Martin

    2017-11-01

    In our contribution we propose to use of a two-mode optical fiber as a primary source in a transmitting optical head instead of the laser diode. The distribution of the optical intensity and the complex degree of the coherence on the output aperture of the lens that is irradiated by a step-index weakly guiding optical fiber is investigated. In our treatment we take into account weakly guided modes with polarization corrections to the propagation constant and unified theory of second order coherence and polarization of electromagnetic beams.

  9. Optical Finite Element Processor

    Science.gov (United States)

    Casasent, David; Taylor, Bradley K.

    1986-01-01

    A new high-accuracy optical linear algebra processor (OLAP) with many advantageous features is described. It achieves floating point accuracy, handles bipolar data by sign-magnitude representation, performs LU decomposition using only one channel, easily partitions and considers data flow. A new application (finite element (FE) structural analysis) for OLAPs is introduced and the results of a case study presented. Error sources in encoded OLAPs are addressed for the first time. Their modeling and simulation are discussed and quantitative data are presented. Dominant error sources and the effects of composite error sources are analyzed.

  10. Size dependent optical characteristics of chemically deposited

    Indian Academy of Sciences (India)

    Keywords. Thin film; ZnS; CBD method; optical properties. Abstract. ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S2- and Zn2+ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the ...

  11. Optical actuation of micromechanical components

    International Nuclear Information System (INIS)

    Koehler, D.R.

    1997-01-01

    Electromagnetic momentum is a fundamental physical concept that has been demonstrated experimentally and incorporated theoretically in various areas of physics. In spite of the weak character of the electromagnetic momentum transfer process, the combination of latter-day, high-energy laser light sources and microminiature mechanical elements suggested the possibility of optical excitation of these structures. One outcome of the present theoretical analysis is the prediction of an optopiezic effect wherein electromagnetic momentum causes a mechanical stress on a dielectric layer. If this is a valid prediction, such an optically induced, expansional pressure effect could be utilized as an extensional optical-to-mechanical transduction means. copyright 1997 Optical Society of America

  12. Springer handbook of lasers and optics

    CERN Document Server

    2012-01-01

    The Springer Handbook of Lasers and Optics provides fast, up-to-date, comprehensive and authoritative coverage of the wide fields of optics and lasers. It is written for daily use in the office or laboratory and offers explanatory text, data, and references needed for anyone working with lasers and optical instruments. This second edition features numerous updates and additions. Especially four new chapters on Fiber Optics, Integrated Optics, Frequency Combs, and Interferometry reflect the major changes. In addition, chapters Optical Materials and Their Properties, Optical Detectors, Nanooptics, and Optics far Beyond the Diffraction Limit have been thoroughly revised and updated. The now 25 chapters are grouped into four parts which cover basic principles and materials, fabrication and properties of optical components, coherent and incoherent light sources, and, finally, selected applications and special fields such as terahertz photonics, x-ray optics and holography. Each chapter is authored by respected exp...

  13. Applied optics and optical design

    CERN Document Server

    Conrady, Alexander Eugen

    1957-01-01

    ""For the optical engineer it is an indispensable work."" - Journal, Optical Society of America""As a practical guide this book has no rival."" - Transactions, Optical Society""A noteworthy contribution,"" - Nature (London)Part I covers all ordinary ray-tracing methods, together with the complete theory of primary aberrations and as much of higher aberration as is needed for the design of telescopes, low-power microscopes and simple optical systems. Chapters: Fundamental Equations, Spherical Aberration, Physical Aspect of Optical Images, Chromatic Aberration, Design of Achromatic Object-Glass

  14. 1993 CAT workshop on beamline optical designs

    International Nuclear Information System (INIS)

    1993-11-01

    An Advanced Photon Source (APS) Collaborative Access Team (CAT) Workshop on Beamline Optical Designs was held at Argonne National Laboratory on July 26--27, 1993. The goal of this workshop was to bring together experts from various synchrotron sources to provide status reports on crystal, reflecting, and polarizing optics as a baseline for discussions of issues facing optical designers for CAT beamlines at the APS. Speakers from the European Synchrotron Radiation Facility (ESRF), the University of Chicago, the National Synchrotron Light Source, and the University of Manchester (England) described single- and double-crystal monochromators, mirrors, glass capillaries, and polarizing optics. Following these presentations, the 90 participants divided into three working groups: Crystal Optics Design, Reflecting Optics, and Optics for Polarization Studies. This volume contains copies of the presentation materials from all speakers, summaries of the three working groups, and a ''catalog'' of various monochromator designs

  15. 1993 CAT workshop on beamline optical designs

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    An Advanced Photon Source (APS) Collaborative Access Team (CAT) Workshop on Beamline Optical Designs was held at Argonne National Laboratory on July 26--27, 1993. The goal of this workshop was to bring together experts from various synchrotron sources to provide status reports on crystal, reflecting, and polarizing optics as a baseline for discussions of issues facing optical designers for CAT beamlines at the APS. Speakers from the European Synchrotron Radiation Facility (ESRF), the University of Chicago, the National Synchrotron Light Source, and the University of Manchester (England) described single- and double-crystal monochromators, mirrors, glass capillaries, and polarizing optics. Following these presentations, the 90 participants divided into three working groups: Crystal Optics Design, Reflecting Optics, and Optics for Polarization Studies. This volume contains copies of the presentation materials from all speakers, summaries of the three working groups, and a ``catalog`` of various monochromator designs.

  16. Nonimaging optical illumination system

    Energy Technology Data Exchange (ETDEWEB)

    Winston, R.; Ries, H.

    2000-02-01

    A nonimaging illumination optical device for producing a selected far field illuminance over an angular range. The optical device includes a light source, a light reflecting surface, and a family of light edge rays defined along a reference line with the reflecting surface defined in terms of the reference line 104 as a parametric function R(t) where t is a scalar parameter position and R(t) = k(t) + Du(t) where k(t) is a parameterization of the reference line 104, and D is a distance from a point on the reference line 104 to the reflection surface 108 along the desired edge ray through the point.

  17. Center for X-ray Optics, 1988

    International Nuclear Information System (INIS)

    1989-04-01

    This report briefly reviews the following topics: soft-x-ray imaging; reflective optics for hard x-rays; coherent XUV sources; spectroscopy with x-rays; detectors for coronary artery imaging; synchrotron-radiation optics; and support for the advanced light source

  18. Optical electronics

    CERN Document Server

    Yariv, Amnon

    1991-01-01

    This classic text introduces engineering students to the first principles of major phenomena and devices of optoelectronics and optical communication technology. Yariv's "first principles" approach employs real-life examples and extensive problems. The text includes separate chapters on quantum well and semiconductor lasers, as well as phase conjugation and its applications. Optical fiber amplification, signal and noise considerations in optical fiber systems, laser arrays and distributed feedback lasers all are covered extensively in major sections within chapters.

  19. Optical computing.

    Science.gov (United States)

    Stroke, G. W.

    1972-01-01

    Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.

  20. Optical fibers and RF a natural combination

    CERN Document Server

    Romeiser, Malcolm

    2004-01-01

    The optical fiber industry has experienced a period of consolidation and reorganization and is now poised for a new surge in growth. To take advantage of that growth, and to respond to the demand to use fiber more efficiently, designers need a better understanding of fiber optics. Taking the approach that optical fibers are an extension of RF-based communications, the author explains basic optical concepts, applications, and systems; the nature and performance characteristics of optical fibers; and optical sources, connectors and splices. Subsequent chapters explore current applications of fib