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Sample records for single laser shot

  1. Radiation damage to amorphous carbon thin films irradiated by multiple 46.9 nm laser shots below the single-shot damage threshold

    Czech Academy of Sciences Publication Activity Database

    Juha, Libor; Hájková, Věra; Chalupský, Jaromír; Vorlíček, Vladimír; Ritucci, A.; Reale, A.; Zuppella, P.; Störmer, M.

    2009-01-01

    Roč. 105, č. 9 (2009), 093117/1-093117/3 ISSN 0021-8979 R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : single-shot damage threshold * multiple-shot exposure damage * amorphous carbon * radiation erosion * capillary-discharge XUV laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.072, year: 2009

  2. Single-Shot, Volumetrically Illuminated, Three-Dimensional, Tomographic Laser-Induced-Fluorescence Imaging in a Gaseous Free Jet

    Science.gov (United States)

    2016-04-28

    Single- shot , volumetrically illuminated, three- dimensional, tomographic laser-induced- fluorescence imaging in a gaseous free jet Benjamin R. Halls...37081 Göttingen, Germany 4School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA 5trmeyer@purdue.edu 6james.gord...us.af.mil Abstract: Single- shot , tomographic imaging of the three-dimensional concentration field is demonstrated in a turbulent gaseous free jet in co-flow

  3. Frequency-Domain Tomography for Single-shot, Ultrafast Imaging of Evolving Laser-Plasma Accelerators

    Science.gov (United States)

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Downer, Michael

    2011-10-01

    Intense laser pulses propagating through plasma create plasma wakefields that often evolve significantly, e.g. by expanding and contracting. However, such dynamics are known in detail only through intensive simulations. Laboratory visualization of evolving plasma wakes in the ``bubble'' regime is important for optimizing and scaling laser-plasma accelerators. Recently snap-shots of quasi-static wakes were recorded using frequency-domain holography (FDH). To visualize the wake's evolution, we have generalized FDH to frequency-domain tomography (FDT), which uses multiple probes propagating at different angles with respect to the pump pulse. Each probe records a phase streak, imprinting a partial record of the evolution of pump-created structures. We then topographically reconstruct the full evolution from all phase streaks. To prove the concept, a prototype experiment visualizing nonlinear index evolution in glass is demonstrated. Four probes propagating at 0, 0.6, 2, 14 degrees to the index ``bubble'' are angularly and temporally multiplexed to a single spectrometer to achieve cost-effective FDT. From these four phase streaks, an FDT algorithm analogous to conventional CT yields a single-shot movie of the pump's self-focusing dynamics.

  4. Optimization And Single-Shot Characterization Of Ultrashort Thz Pulses From A Laser Wakefield Accelerator

    International Nuclear Information System (INIS)

    Plateau, G.R.; Matlis, N.H.; van Tilborg, J.; Geddes, C.G.R.; Toth, Cs.; Schroeder, C.B.; Leemans, W.P.

    2009-01-01

    We present spatiotemporal characterization of μJ-class ultrashort THz pulses generated from a laser wakefield accelerator (LWFA). Accelerated electrons, resulting from the interaction of a high-intensity laser pulse with a plasma, emit high-intensity THz pulses as coherent transition radiation. Such high peak-power THz pulses, suitable for high-field (MV/cm) pump-probe experiments, also provide a non-invasive bunch-length diagnostic and thus feedback for the accelerator. The characterization of the THz pulses includes energy measurement using a Golay cell, 2D sign-resolved electro-optic measurement and single-shot spatiotemporal electric-field distribution retrieval using a new technique, coined temporal electric-field cross-Correlation (TEX). All three techniques corroborate THz pulses of ∼ 5 μJ, with peak fields of 100's of kV/cm and ∼ 0.4 ps rms duration.

  5. Method for single-shot measurement of picosecond laser pulse-lengths without electronic time dispersion

    International Nuclear Information System (INIS)

    Kyrala, G.A.

    1987-01-01

    A two-source shear pattern recording is proposed as a method for single-shot measurement of the pulse shape from nearly monochromatic sources whose pulse lengths are shorter than their coherence times. The basis of this method relies on the assertion that if two identical electromagnetic pulses are recombined with a time delay greater than the sum of their pulse widths, the recordable spatial pattern has no fringes in it. At an arbitrary delay, translated into an actual spatial recording position, the recorded modulated intensity will sample the corresponding laser intensity at that delay time, but with a modulation due to the coherence function of the electromagnetic pulse. Two arrangements are proposed for recording the pattern. The principles, the design parameters, and the methodologies of these arrangements are presented. Resolutions of the configurations and their limitations are given as well

  6. Measurement of the single-shot pulse energy of a free electron laser using a cryogenic radiometer

    Energy Technology Data Exchange (ETDEWEB)

    Masahiro, Kato; Norio, Saito; Yuichiro, Morishita; Takahiro, Tanaka [National Institute of Advanced Industrial Science and Technology (AIST), NMIJ, Tsukuba (Japan); Masahiro, Kato; Norio, Saito; Kai, Tiedtke; Pavle N, Juranic; Sorokin, A.A.; Richter, M.; Takahiro, Tanaka; Mitsuru, Nagasono; Makina, Yabashi; Kensuke, Tono; Tadashi, Togashi; Tetsuya, Ishikawa [RIKEN, XFEL Project Head Office, Kouto, Sayo, Hyogo (Japan); Kai, Tiedtke; Pavle N, Juranic; Sorokin, A.A.; Jastrow, U. [Deutsches Elektronen-Synchrotron, DESY, Hamburg (Germany); Sorokin, A.A. [Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St Petersburg (Russian Federation); Richter, M.; Kroth, U.; Schoppe, H. [Physikalisch-Technische Bundesanstalt, PTB, Berlin (Germany); Tadashi, Togashi; Hiroaki, Kimura; Haruhiko, Ohashi [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo (Japan)

    2010-10-15

    The absolute single-shot pulse energy of the SPring 8 extreme ultraviolet (EUV) free electron laser (FEL) was measured using a cryogenic radiometer with a relative standard uncertainty of 3%. The temperature change of the cavity in the cryogenic radiometer caused by an incident FEL pulse was determined using a lock-in amplifier and an ac Wheatstone bridge. The measured pulse energies were compared with a gas-monitor detector developed by Physikalisch-Technische Bundesanstalt/Deutsches Elektronen-Synchrotron/Ioffe Physico-Technical Institute (Ioffe) at a wavelength of 51.3 nm at the SPring-8 EUV-FEL in a shot-to-shot mode. The pulse energies measured using the two detectors agree within 2.0%. (authors)

  7. Single-shot photonic time-stretch digitizer using a dissipative soliton-based passively mode-locked fiber laser.

    Science.gov (United States)

    Peng, Di; Zhang, Zhiyao; Zeng, Zhen; Zhang, Lingjie; Lyu, Yanjia; Liu, Yong; Xie, Kang

    2018-03-19

    We demonstrate a single-shot photonic time-stretch digitizer using a dissipative soliton-based passively mode-locked fiber laser. The theoretical analysis and simulation results indicate that the dissipative soliton-based optical source with a flat spectrum relieves the envelope-induced signal distortion, and its high energy spectral density helps to improve the signal-to-noise ratio, both of which are favorable for simplifying the optical front-end architecture of a photonic time-stretch digitizer. By employing a homemade dissipative soliton-based passively mode-locked erbium-doped fiber laser in a single-shot photonic time-stretch digitizer, an effective number of bits of 4.11 bits under an effective sampling rate of 100 GS/s is experimentally obtained without optical amplification in the link and pulse envelope removing process.

  8. Absolute Quantification of Rifampicin by MALDI Imaging Mass Spectrometry Using Multiple TOF/TOF Events in a Single Laser Shot.

    Science.gov (United States)

    Prentice, Boone M; Chumbley, Chad W; Caprioli, Richard M

    2017-01-01

    Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) allows for the visualization of molecular distributions within tissue sections. While providing excellent molecular specificity and spatial information, absolute quantification by MALDI IMS remains challenging. Especially in the low molecular weight region of the spectrum, analysis is complicated by matrix interferences and ionization suppression. Though tandem mass spectrometry (MS/MS) can be used to ensure chemical specificity and improve sensitivity by eliminating chemical noise, typical MALDI MS/MS modalities only scan for a single MS/MS event per laser shot. Herein, we describe TOF/TOF instrumentation that enables multiple fragmentation events to be performed in a single laser shot, allowing the intensity of the analyte to be referenced to the intensity of the internal standard in each laser shot while maintaining the benefits of MS/MS. This approach is illustrated by the quantitative analyses of rifampicin (RIF), an antibiotic used to treat tuberculosis, in pooled human plasma using rifapentine (RPT) as an internal standard. The results show greater than 4-fold improvements in relative standard deviation as well as improved coefficients of determination (R 2 ) and accuracy (>93% quality controls, errors). This technology is used as an imaging modality to measure absolute RIF concentrations in liver tissue from an animal dosed in vivo. Each microspot in the quantitative image measures the local RIF concentration in the tissue section, providing absolute pixel-to-pixel quantification from different tissue microenvironments. The average concentration determined by IMS is in agreement with the concentration determined by HPLC-MS/MS, showing a percent difference of 10.6%. Graphical Abstract ᅟ.

  9. Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives

    Energy Technology Data Exchange (ETDEWEB)

    Whitley, Von H [Los Alamos National Laboratory; Mcgrane, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Eakins, Dan E [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory

    2009-01-01

    We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, sample quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.

  10. Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass

    Energy Technology Data Exchange (ETDEWEB)

    Garzillo, Valerio; Grigutis, Robertas [Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Via Valleggio 11, I-22100 Como (Italy); Jukna, Vytautas [Centre de Physique Theorique, CNRS, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau (France); LOA, ENSTA-ParisTech, CNRS, Ecole Polytechnique, Université Paris Saclay, F-91762 Palaiseau (France); Couairon, Arnaud [Centre de Physique Theorique, CNRS, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau (France); Di Trapani, Paolo [Dipartimento di Scienza e Alta Tecnologia, University of Insubria and CNISM UdR Como, Via Valleggio 11, I-22100 Como (Italy); Jedrkiewicz, Ottavia, E-mail: ottavia.jedrkiewicz@ifn.cnr.it [Istituto di Fotonica e Nanotecnologie, CNR and CNISM UdR Como, Via Valleggio 11, I-22100 Como (Italy)

    2016-07-07

    We investigate the generation of high aspect ratio microstructures across 0.7 mm thick glass by means of single shot Bessel beam laser direct writing. We study the effect on the photoinscription of the cone angle, as well as of the energy and duration of the ultrashort laser pulse. The aim of the study is to optimize the parameters for the writing of a regular microstructure due to index modification along the whole sample thickness. By using a spectrally resolved single pulse transmission diagnostics at the output surface of the glass, we correlate the single shot material modification with observations of the absorption in different portions of the retrieved spectra, and with the absence or presence of spectral modulation. Numerical simulations of the evolution of the Bessel pulse intensity and of the energy deposition inside the sample help us interpret the experimental results that suggest to use picosecond pulses for an efficient and more regular energy deposition. Picosecond pulses take advantage of nonlinear plasma absorption and avoid temporal dynamics effects which can compromise the stationarity of the Bessel beam propagation.

  11. FLASH free-electron laser single-shot temporal diagnostic: terahertz-field-driven streaking.

    Science.gov (United States)

    Ivanov, Rosen; Liu, Jia; Brenner, Günter; Brachmanski, Maciej; Düsterer, Stefan

    2018-01-01

    The commissioning of a terahertz-field-driven streak camera installed at the free-electron laser (FEL) FLASH at DESY in Hamburg, being able to deliver photon pulse duration as well as arrival time information with ∼10 fs resolution for each single XUV FEL pulse, is reported. Pulse durations between 300 fs and terahertz-streaking setup was operated simultaneously to an alternative method to determine the FEL pulse duration based on spectral analysis. FLASH pulse duration derived from simple spectral analysis is in good agreement with that from terahertz-streaking measurement.

  12. Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser

    Science.gov (United States)

    de Ninno, Giovanni; Gauthier, David; Mahieu, Benoît; Ribič, Primož Rebernik; Allaria, Enrico; Cinquegrana, Paolo; Danailov, Miltcho Bojanov; Demidovich, Alexander; Ferrari, Eugenio; Giannessi, Luca; Penco, Giuseppe; Sigalotti, Paolo; Stupar, Matija

    2015-08-01

    Intense ultrashort X-ray pulses produced by modern free-electron lasers (FELs) allow one to probe biological systems, inorganic materials and molecular reaction dynamics with nanoscale spatial and femtoscale temporal resolution. These experiments require the knowledge, and possibly the control, of the spectro-temporal content of individual pulses. FELs relying on seeding have the potential to produce spatially and temporally fully coherent pulses. Here we propose and implement an interferometric method, which allows us to carry out the first complete single-shot spectro-temporal characterization of the pulses, generated by an FEL in the extreme ultraviolet spectral range. Moreover, we provide the first direct evidence of the temporal coherence of a seeded FEL working in the extreme ultraviolet spectral range and show the way to control the light generation process to produce Fourier-limited pulses. Experiments are carried out at the FERMI FEL in Trieste.

  13. Characterization of temporal coherence of hard X-ray free-electron laser pulses with single-shot interferograms

    Directory of Open Access Journals (Sweden)

    Taito Osaka

    2017-11-01

    Full Text Available Temporal coherence is one of the most fundamental characteristics of light, connecting to spectral information through the Fourier transform relationship between time and frequency. Interferometers with a variable path-length difference (PLD between the two branches have widely been employed to characterize temporal coherence properties for broad spectral regimes. Hard X-ray interferometers reported previously, however, have strict limitations in their operational photon energies, due to the specific optical layouts utilized to satisfy the stringent requirement for extreme stability of the PLD at sub-ångström scales. The work presented here characterizes the temporal coherence of hard X-ray free-electron laser (XFEL pulses by capturing single-shot interferograms. Since the stability requirement is drastically relieved with this approach, it was possible to build a versatile hard X-ray interferometer composed of six separate optical elements to cover a wide photon energy range from 6.5 to 11.5 keV while providing a large variable delay time of up to 47 ps at 10 keV. A high visibility of up to 0.55 was observed at a photon energy of 10 keV. The visibility measurement as a function of time delay reveals a mean coherence time of 5.9 ± 0.7 fs, which agrees with that expected from the single-shot spectral information. This is the first result of characterizing the temporal coherence of XFEL pulses in the hard X-ray regime and is an important milestone towards ultra-high energy resolutions at micro-electronvolt levels in time-domain X-ray spectroscopy, which will open up new opportunities for revealing dynamic properties in diverse systems on timescales from femtoseconds to nanoseconds, associated with fluctuations from ångström to nanometre spatial scales.

  14. Single-shot measurements of low emittance beams from laser-plasma accelerators comparing two triggered injection methods

    Science.gov (United States)

    van Tilborg, Jeroen

    2017-10-01

    The success of laser plasma accelerator (LPA) based applications, such as a compact x-ray free electron laser (FEL), relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot energy-dispersed emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock-induced density down-ramp injection. Both injection mechanisms have gained in popularity in recent years due to their demonstrated stable LPA performance. For the down-ramp injection configuration, normalized emittances a factor of two lower were recorded: less than 1 micron at spectral charge densities up to 2 pC/MeV. For both injection mechanisms, a contributing correlation of space charge to the emittance was identified. This measurement technique in general, and these results specifically, are critical to the evaluation of LPA injection methods and development of high-quality LPA beam lines worldwide. This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the U.S. DOE NNSA, DNN R&D (NA22), by the National Science Foundation under Grant No. PHY-1415596, and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

  15. Single-shot beam-position monitor for x-ray free electron laser

    Science.gov (United States)

    Tono, Kensuke; Kudo, Togo; Yabashi, Makina; Tachibana, Takeshi; Feng, Yiping; Fritz, David; Hastings, Jerome; Ishikawa, Tetsuya

    2011-02-01

    We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 μm by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

  16. Development of Laser Rifle Trainer with Full Shot Imitation

    OpenAIRE

    Bansevicius, Ramutis; Fedaravicius, Algimantas; Ostasevicius, Vytautas; Ragulskis, Minvydas

    2004-01-01

    Laser trainers are effective tools for shot and sportsmen training. However, the majority of trainers have neither realistic recoil nor sound imitation systems. The objective of the development of laser rifle trainer with full shot imitation was to investigate and simulate the recoil of combat weapons under single and serial shooting regimes so that the training weapons could simulate complete recoil and sound imitation.Theoretical and experimental investigations lead to the development of sh...

  17. Development of Laser Rifle Trainer with Full Shot Imitation

    Directory of Open Access Journals (Sweden)

    Ramutis Bansevicius

    2004-01-01

    Full Text Available Laser trainers are effective tools for shot and sportsmen training. However, the majority of trainers have neither realistic recoil nor sound imitation systems. The objective of the development of laser rifle trainer with full shot imitation was to investigate and simulate the recoil of combat weapons under single and serial shooting regimes so that the training weapons could simulate complete recoil and sound imitation.

  18. Wavefront Analysis of Nonlinear Self-Amplified Spontaneous-Emission Free-Electron Laser Harmonics in the Single-Shot Regime

    Energy Technology Data Exchange (ETDEWEB)

    Bachelard, R.; Chubar, O.; Mercere, P.; Idir, M.; Couprie, M.E.; Lambert, G.; Zeitoun, Ph.; Kimura, H.; Ohashi, H.; Higashiya, A.; Yabashi, M.; Nagasono, M.; Hara, T. and Ishikawa, T.

    2011-06-08

    The single-shot spatial characteristics of the vacuum ultraviolet self-amplified spontaneous emission of a free electron laser (FEL) is measured at different stages of amplification up to saturation with a Hartmann wavefront sensor. We show that the fundamental radiation at 61.5 nm tends towards a single-mode behavior as getting closer to saturation. The measurements are found in good agreement with simulations and theory. A near diffraction limited wavefront was measured. The analysis of Fresnel diffraction through the Hartmann wavefront sensor hole array also provides some further insight for the evaluation of the FEL transverse coherence, of high importance for various applications.

  19. Infrared-spectroscopic single-shot laser mapping ellipsometry: Proof of concept for fast investigations of structured surfaces and interactions in organic thin films

    Science.gov (United States)

    Furchner, Andreas; Kratz, Christoph; Gkogkou, Dimitra; Ketelsen, Helge; Hinrichs, Karsten

    2017-11-01

    We present a novel infrared-spectroscopic laser mapping ellipsometer based on a single-shot measurement concept. The ellipsometric set-up employs multiple analyzers and detectors to simultaneously measure the sample's optical response under different analyzer azimuths. An essential component is a broadly tunable quantum cascade laser (QCL) covering the important marker region of 1800-1540 cm-1. The ellipsometer allows for fast single-wavelength as well as spectroscopic studies with thin-film sensitivity at temporal resolutions of 60 ms per wavelength. We applied the single-shot mapping ellipsometer for the characterization of metal-island enhancement surfaces as well as of molecular interactions in organic thin films. In less than 3 min, a linescan with 1600 steps revealed profile and infrared-enhancement properties of a gradient gold-island film for sensing applications. Spectroscopic measurements were performed to probe the amide I band of thin films of poly(N-isopropylacrylamide) [PNIPAAm], a stimuli-responsive polymer for bioapplications. The QCL spectra agree well with conventional FT-IR ellipsometric results, showing different band components associated with hydrogen-bond interactions between polymer and adsorbed water. Multi-wavelength ellipsometric maps were used to analyze homogeneity and surface contaminations of the polymer films.

  20. Measurement of the X-ray Spectrum of a Free Electron Laser with a Wide-Range High-Resolution Single-Shot Spectrometer

    Directory of Open Access Journals (Sweden)

    Yuichi Inubushi

    2017-06-01

    Full Text Available We developed a single-shot X-ray spectrometer for wide-range high-resolution measurements of Self-Amplified Spontaneous Emission (SASE X-ray Free Electron Laser (XFEL pulses. The spectrometer consists of a multi-layer elliptical mirror for producing a large divergence of 22 mrad around 9070 eV and a silicon (553 analyzer crystal. We achieved a wide energy range of 55 eV with a fine spectral resolution of 80 meV, which enabled the observation of a whole SASE-XFEL spectrum with fully-resolved spike structures. We found that a SASE-XFEL pulse has around 60 longitudinal modes with a pulse duration of 7.7 ± 1.1 fs.

  1. The single-shot opto-digitizer

    International Nuclear Information System (INIS)

    Nail, M.; Gibert, Ph.

    2000-01-01

    Laser-plasma experiments need to measure signals provided either by X-ray, photonic or neutronic detector. The measurement should have 50 GHz bandwidth and up to several hundred of Giga-Hertz for sub picosecond plasmas. For this purpose, a 35 GHz single shot opto-digitizer (10 ps risetime) has been studied and built. The device is made up of a 50 ohms microstrip propagation line, periodically lined by 100 sampled gates. The propagation line is long enough to measure a 400 ps duration. The sampling rate is 250 Gsa/s (every 4 ps). The sampled gates are made with fast recombining photo-material and turn on by a subpicosecond laser pulse which is synchronized exactly with the analysed phenomena. Every gate is recording to a storing capacitor. After the recording, every capacitor charge is needed to built the signal that was displayed on the propagation line. The dynamic range of measurement is 47 for the entire device. The device can measure positive or negative signals from 1.5 to 70 Volts. To increase the bandwidth, two another kinds of opto-digitizer were studied: one is a buried stripline with 56 GHz band width, the other a 70 GHz coplanar transmission line. For the purpose of subpicosecond plasmas, a 30 coplanar waveguide opto-digitizer was studied. Characteristics are as followed: window of measurement 40 ps, sampling rate 1 ps, bandwidth 230 GHz. Finally, a bundle of optical fibers was used to propagate the laser beam on semiconductor gates. If the gates are lighted at the same time, i.e. if the optical fibers have the same length, we get a simultaneous addressing. By using different lengths of optical fibers, we can do a sequential addressing. So, the sampling rate becomes a combination of the distance between two adjacent sampled channels, and the difference in length of optical fibers. (author)

  2. Broadband femtosecond OPCPA system driven by the single-shot narrow-band iodine photodissociation laser SOFIA

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Turčičová, Hana; Smrž, Martin; Huynh, Jaroslav; Pfeifer, Miroslav; Straka, Petr

    2012-01-01

    Roč. 108, č. 3 (2012), s. 501-508 ISSN 0946-2171 R&D Projects: GA ČR GA202/06/0814; GA MŠk(CZ) LC528 EU Projects: European Commission(XE) 506350 - LASER LAB-EUROPE Institutional research plan: CEZ:AV0Z10100523 Keywords : OPCPA * ultrashort laser pulses * optical parametric amplifiers * Iodine laser s * gas laser s * nonlinear optical crystals, * petawatt laser s Subject RIV: BH - Optics, Masers, Laser s Impact factor: 1.782, year: 2012 http://www.springerlink.com/content/5l263x8722204606/

  3. Single-shot 35 fs temporal resolution electron shadowgraphy

    Energy Technology Data Exchange (ETDEWEB)

    Scoby, C. M.; Li, R. K.; Threlkeld, E.; To, H.; Musumeci, P. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States)

    2013-01-14

    We obtain single-shot time-resolved shadowgraph images of the electromagnetic fields resulting from the interaction of a high intensity ultrashort laser pulse with a metal surface. Using a high brightness relativistic electron beam and a high streaking speed radiofrequency deflector, we report <35 fs temporal resolution enabling a direct visualization of the retarded-time dominated field evolution which follows the laser-induced charge emission. A model including the finite signal propagation speed well reproduces the data and yields measurements of fundamental parameters in short pulse laser-matter interaction such as the amount of emitted charge and the emission time scale.

  4. Single-shot soft x-ray laser-induced ablative microstructuring of organic polymer with demagnifying projection

    Czech Academy of Sciences Publication Activity Database

    Mocek, Tomáš; Rus, Bedřich; Kozlová, Michaela; Polan, Jiří; Homer, Pavel; Juha, Libor; Hájková, Věra; Chalupský, Jaromír

    2008-01-01

    Roč. 33, č. 10 (2008), s. 1087-1089 ISSN 0146-9592 R&D Projects: GA AV ČR KAN300100702; GA ČR GA202/05/2316; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024 Institutional research plan: CEZ:AV0Z10100523 Keywords : x-ray lasers * laser ablation * microstructuring Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.772, year: 2008

  5. Time-resolved single-shot terahertz time-domain spectroscopy for ultrafast irreversible processes

    Science.gov (United States)

    Zhai, Zhao-Hui; Zhong, Sen-Cheng; Li, Jun; Zhu, Li-Guo; Meng, Kun; Li, Jiang; Liu, Qiao; Peng, Qi-Xian; Li, Ze-Ren; Zhao, Jian-Heng

    2016-09-01

    Pulsed terahertz spectroscopy is suitable for spectroscopic diagnostics of ultrafast events. However, the study of irreversible or single shot ultrafast events requires ability to record transient properties at multiple time delays, i.e., time resolved at single shot level, which is not available currently. Here by angular multiplexing use of femtosecond laser pulses, we developed and demonstrated a time resolved, transient terahertz time domain spectroscopy technique, where burst mode THz pulses were generated and then detected in a single shot measurement manner. The burst mode THz pulses contain 2 sub-THz pulses, and the time gap between them is adjustable up to 1 ns with picosecond accuracy, thus it can be used to probe the single shot event at two different time delays. The system can detect the sub-THz pulses at 0.1 THz-2.5 THz range with signal to noise ratio (SNR) of ˜400 and spectrum resolution of 0.05 THz. System design was described here, and optimizations of single shot measurement of THz pulses were discussed in detail. Methods to improve SNR were also discussed in detail. A system application was demonstrated where pulsed THz signals at different time delays of the ultrafast process were successfully acquired within single shot measurement. This time resolved transient terahertz time domain spectroscopy technique provides a new diagnostic tool for irreversible or single shot ultrafast events where dynamic information can be extracted at terahertz range within one-shot experiment.

  6. Laser conditioning and multi-shot laser damage accumulation effects of HfO2/SiO2 antireflective coatings

    International Nuclear Information System (INIS)

    Zhao Yuanan; Wang Tao; Zhang Dawei; Shao Jianda; Fan Zhengxiu

    2005-01-01

    Laser conditioning effects of the HfO 2 /SiO 2 antireflective (AR) coatings at 1064 nm and the accumulation effects of multi-shot laser radiation were investigated. The HfO 2 /SiO 2 AR coatings were prepared by E-beam evaporation (EBE). The single-shot and multi-shot laser induced damage threshold was detected following ISO standard 11254-1.2, and the laser conditioning was conducted by three-step raster scanning method. It was found that the single-shot LIDT and multi-shot LIDT was almost the same. The damage mostly >80% occurred in the first shot under multi-shot laser radiation, and after that the damage occurring probability plummeted to <5%. There was no obvious enhancement of the laser damage resistance for both the single-shot and multi-shot laser radiation of the AR coatings after laser conditioning. A Nomarski microscope was employed to map the damage morphology, and it found that the damage behavior is defect-initiated for both unconditioned and conditioned samples

  7. Synchronizing single-shot high-energy iodine photodissociation laser PALS and high-repetition-rate femtosecond Ti:sapphire laser system

    Czech Academy of Sciences Publication Activity Database

    Dostál, Jan; Dudžák, Roman; Pisarczyk, T.; Pfeifer, Miroslav; Huynh, Jaroslav; Chodukowski, T.; Kalinowska, Z.; Krouský, E.; Skála, J.; Hřebíček, Jan; Medřík, Tomáš; Golasowski, Jiří; Juha, Libor; Ullschmied, J.

    2017-01-01

    Roč. 88, č. 4 (2017), s. 1-11, č. článku 045109. ISSN 0034-6748 Institutional support: RVO:68378271 Keywords : oscillators * plasma diagnostics * optical signal processing * mode locking * laser amplifiers Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.515, year: 2016

  8. Synchronizing single-shot high-energy iodine photodissociation laser PALS and high-repetition-rate femtosecond Ti:sapphire laser system

    Czech Academy of Sciences Publication Activity Database

    Dostál, Jan; Dudžák, Roman; Pisarczyk, T.; Pfeifer, Miroslav; Huynh, J.; Chodukowski, T.; Kalinowska, Z.; Krouský, Eduard; Skála, Jiří; Hřebíček, Jan; Medřík, Tomáš; Golasowski, Jiří; Juha, Libor; Ullschmied, Jiří

    2017-01-01

    Roč. 88, č. 4 (2017), č. článku 045109. ISSN 0034-6748 R&D Projects: GA MŠk LM2010014; GA MŠk(CZ) LM2015083; GA ČR GPP205/11/P712 Institutional support: RVO:61389021 Keywords : oscillators * plasma diagnostics * optical signal processing * mode locking * laser amplifiers Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 2.11 Other engineering and technologies Impact factor: 1.515, year: 2016 https://aip.scitation.org/doi/10.1063/1.4979810

  9. Single shot damage mechanism of Mo/Si multilayer optics under intense pulsed XUV-exposures

    NARCIS (Netherlands)

    Khorsand, A.R.; Sobierajski, R.; Louis, Eric; Bruijn, S.; Gleeson, A.; van de Kruijs, Robbert Wilhelmus Elisabeth; Gullikson, E.M.; Bijkerk, Frederik

    2010-01-01

    We investigated single shot damage of Mo/Si multilayer coatings exposed to the intense fs XUV radiation at the Free-electron LASer facility in Hamburg - FLASH. The interaction process was studied in situ by XUV reflectometry, time resolved optical microscopy, and “post-mortem” by

  10. Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor; Wu, Juhao; /SLAC

    2012-05-10

    We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomic states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).

  11. Single shot high resolution digital holography.

    Science.gov (United States)

    Khare, Kedar; Ali, P T Samsheer; Joseph, Joby

    2013-02-11

    We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.

  12. Tabletop single-shot extreme ultraviolet Fourier transform holography of an extended object.

    Science.gov (United States)

    Malm, Erik B; Monserud, Nils C; Brown, Christopher G; Wachulak, Przemyslaw W; Xu, Huiwen; Balakrishnan, Ganesh; Chao, Weilun; Anderson, Erik; Marconi, Mario C

    2013-04-22

    We demonstrate single and multi-shot Fourier transform holography with the use of a tabletop extreme ultraviolet laser. The reference wave was produced by a Fresnel zone plate with a central opening that allowed the incident beam to illuminate the sample directly. The high reference wave intensity allows for larger objects to be imaged compared to mask-based lensless Fourier transform holography techniques. We obtain a spatial resolution of 169 nm from a single laser pulse and a resolution of 128 nm from an accumulation of 20 laser pulses for an object ~11x11μm(2) in size. This experiment utilized a tabletop extreme ultraviolet laser that produces a highly coherent ~1.2 ns laser pulse at 46.9 nm wavelength.

  13. Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold

    Czech Academy of Sciences Publication Activity Database

    Makhotkin, I.; Sobierajski, R.; Chalupský, Jaromír; Tiedtke, K.; de Vries, G.; Stoermer, M.; Scholze, F.; Siewert, F.; van de Kruijs, R.W.E.; Milov, I.; Louis, E.; Jacyna, I.; Jurek, M.; Klinger, D.; Nittler, L.; Syryanyy, Y.; Juha, Libor; Hájková, Věra; Vozda, Vojtěch; Burian, Tomáš; Saksl, Karel; Faatz, B.; Keitel, B.; Ploenjes, E.; Schreiber, S.; Toleikis, S.; Loch, R.A.; Hermann, M.; Strobel, S.; Nienhuys, H.-K.; Gwalt, G.; Mey, T.; Enkisch, H.

    2018-01-01

    Roč. 25, č. 1 (2018), s. 77-84 ISSN 1600-5775. [Workshop on FEL Photon Diagnostics, Instrumentation and Beamline Design (PhotonDiag2017). Stanford, 01.05.2017-03.05.2017] R&D Projects: GA MŠk LG15013; GA ČR(CZ) GA17-05167s; GA ČR(CZ) GA14-29772S Institutional support: RVO:68378271 Keywords : free-electron laser induced damage * EUV optics * thin films * FELs Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.011, year: 2016

  14. A High-Power Laser-Driven Source of Sub-nanosecond Soft X-Ray Pulses for Single-Shot Radiobiology Experiments

    Czech Academy of Sciences Publication Activity Database

    Davídková, Marie; Juha, Libor; Bittner, Michal; Koptyaev, Sergey; Hájková, Věra; Krása, Josef; Pfeifer, Miroslav; Štísová, Viktorie; Bartnik, A.; Fiedorowicz, H.; Mikolajczyk, J.; Ryc, L.; Pína, L.; Horváth, M.; Babánková, Dagmar; Cihelka, Jaroslav; Civiš, Svatopluk

    2007-01-01

    Roč. 168, č. 3 (2007), s. 382-387 ISSN 0033-7587 R&D Projects: GA ČR GA202/05/2316; GA MŠk(CZ) LC528; GA MŠk 1P04LA235; GA MŠk LC510 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100523; CEZ:AV0Z20430508; CEZ:AV0Z40400503 Keywords : soft X-rays * radiation damage to DNA * laser-driven source Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.599, year: 2007

  15. Single shot diffraction of picosecond 8.7-keV x-ray pulses

    Directory of Open Access Journals (Sweden)

    F. H. O’Shea

    2012-02-01

    Full Text Available We demonstrate multiphoton, single shot diffraction images of x rays produced by inverse Compton scattering a high-power CO_{2} laser from a relativistic electron beam, creating a pulse of 8.7 keV x rays. The tightly focused, relatively high peak brightness electron beam and high photon density from the 2 J CO_{2} laser yielded 6×10^{7} x-ray photons over the full opening angle in a single shot. Single shot x-ray diffraction is performed by passing the x rays though a vertical slit and on to a flat silicon (111 crystal. 10^{2} diffracted photons were detected. The spectrum of the detected x rays is compared to simulation. The diffraction and detection of 10^{2} x rays is a key step to a more efficient time resolved diagnostic in which the number of observed x rays might reach 10^{4}; enabling a unique, flexible x-ray source as a sub-ps resolution diagnostic for studying the evolution of chemical reactions, lattice deformation and melting, and magnetism.

  16. Infrared single shot diagnostics for the longitudinal profile of the electron bunches at FLASH

    International Nuclear Information System (INIS)

    Delsim-Hashemi, Hossein

    2008-09-01

    The longitudinal profile of electron bunches plays an important role in the design of single-pass free electron lasers and future linear e + e - colliders. For the free electron laser FLASH in Hamburg, a longitudinal compression scheme is used which results in an asymmetric longitudinal bunch profile with a 'spike'. This 'spike', which has a very high peak current, is used in a high-gain SASE-FEL process to produce high intensity (about 70 μJ) femtosecond photon pulses in the XUV wavelength range. The required high peak current of the electron bunch is realized by confining a large number of electrons in a width, measured in time units, of few tens of femtosecond, making the diagnostics of such bunches a challenge. Furthermore, the operation of facilities such as FLASH shows that single-shot diagnostics is indispensable. It is intuitive to use a time domain method to measure the electron bunch length. However, when the structures present in the bunch profile fall in the femtoseconds range, this is beyond the resolution of time-resolved methods developed so far. In this thesis, a wavelength-domain technique is described that can fulfill both requirements of single shot and high resolution reaching to the femtoseconds range. The amount of charge that is confined in a typical length of several femtoseconds (FWHM of the spike) can be determined by a novel single-shot spectrometer that resolves the coherent radiation (e.g. coherent transition radiation) in the far-infrared and mid-infrared range. Furthermore the extension of this single-shot spectroscopy to shorter wavelengths reaching the near-infrared, makes it possible to investigate the presence of structures in the bunch profile that might correlate or anti-correlate to the SASE intensity. (orig.)

  17. Infrared single shot diagnostics for the longitudinal profile of the electron bunches at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Delsim-Hashemi, Hossein

    2008-09-15

    The longitudinal profile of electron bunches plays an important role in the design of single-pass free electron lasers and future linear e{sup +}e{sup -} colliders. For the free electron laser FLASH in Hamburg, a longitudinal compression scheme is used which results in an asymmetric longitudinal bunch profile with a 'spike'. This 'spike', which has a very high peak current, is used in a high-gain SASE-FEL process to produce high intensity (about 70 {mu}J) femtosecond photon pulses in the XUV wavelength range. The required high peak current of the electron bunch is realized by confining a large number of electrons in a width, measured in time units, of few tens of femtosecond, making the diagnostics of such bunches a challenge. Furthermore, the operation of facilities such as FLASH shows that single-shot diagnostics is indispensable. It is intuitive to use a time domain method to measure the electron bunch length. However, when the structures present in the bunch profile fall in the femtoseconds range, this is beyond the resolution of time-resolved methods developed so far. In this thesis, a wavelength-domain technique is described that can fulfill both requirements of single shot and high resolution reaching to the femtoseconds range. The amount of charge that is confined in a typical length of several femtoseconds (FWHM of the spike) can be determined by a novel single-shot spectrometer that resolves the coherent radiation (e.g. coherent transition radiation) in the far-infrared and mid-infrared range. Furthermore the extension of this single-shot spectroscopy to shorter wavelengths reaching the near-infrared, makes it possible to investigate the presence of structures in the bunch profile that might correlate or anti-correlate to the SASE intensity. (orig.)

  18. Effects of Laser Peening, and Shot Peening, on Friction Stir Welding

    Science.gov (United States)

    Hatamleh, Omar; Hackel, Lloyd; Rankin, Jon; Truong, Chanh; Walter, Matt

    2006-01-01

    A viewgraph presentation describing the effects of laser peening and shot peening on friction stir welding is shown. The topics include: 1) Background; 2) Friction Stir Welding (FSW); 3) Microstructure; 4) Laser & Shot Peening; 5) Residual Stresses; 6) Tensile Behavior; 7) Fatigue Life & Surface Roughness; 8) Crack Growth; and 9) Benefits.

  19. 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

  20. Improved focal liver lesion detection: comparison of single-shot diffusion-weighted echoplanar and single-shot T-2 weighted turbo spin echo techniques

    NARCIS (Netherlands)

    Coenegrachts, K.; Delanote, J.; ter Beek, L.; Haspeslagh, M.; Bipat, S.; Stoker, J.; van Kerkhove, F.; Steyaert, L.; Rigauts, H.; Casselman, J. W.

    2007-01-01

    The purpose of this study was to compare diffusion-weighted respiratory-triggered single-shot spin echo echoplanar imaging (SS SE-EPI) sequence using four b-values (b=0, b=20, b=300, b=800 s mm(-2)) and single-shot T-2 weighted turbo spin echo (T2W SS TSE) in patients with focal liver lesions, with

  1. Single-shot work extraction in quantum thermodynamics revisited

    Science.gov (United States)

    Wang, Shang-Yung

    2018-01-01

    We revisit the problem of work extraction from a system in contact with a heat bath to a work storage system, and the reverse problem of state formation from a thermal system state in single-shot quantum thermodynamics. A physically intuitive and mathematically simple approach using only elementary majorization theory and matrix analysis is developed, and a graphical interpretation of the maximum extractable work, minimum work cost of formation, and corresponding single-shot free energies is presented. This approach provides a bridge between two previous methods based respectively on the concept of thermomajorization and a comparison of subspace dimensions. In addition, a conceptual inconsistency with regard to general work extraction involving transitions between multiple energy levels of the work storage system is clarified and resolved. It is shown that an additional contribution to the maximum extractable work in those general cases should be interpreted not as work extracted from the system, but as heat transferred from the heat bath. Indeed, the additional contribution is an artifact of a work storage system (essentially a suspended ‘weight’ that can be raised or lowered) that does not truly distinguish work from heat. The result calls into question the common concept that a work storage system in quantum thermodynamics is simply the quantum version of a suspended weight in classical thermodynamics.

  2. Single-shot polarimetry imaging of multicore fiber.

    Science.gov (United States)

    Sivankutty, Siddharth; Andresen, Esben Ravn; Bouwmans, Géraud; Brown, Thomas G; Alonso, Miguel A; Rigneault, Hervé

    2016-05-01

    We report an experimental test of single-shot polarimetry applied to the problem of real-time monitoring of the output polarization states in each core within a multicore fiber bundle. The technique uses a stress-engineered optical element, together with an analyzer, and provides a point spread function whose shape unambiguously reveals the polarization state of a point source. We implement this technique to monitor, simultaneously and in real time, the output polarization states of up to 180 single-mode fiber cores in both conventional and polarization-maintaining fiber bundles. We demonstrate also that the technique can be used to fully characterize the polarization properties of each individual fiber core, including eigen-polarization states, phase delay, and diattenuation.

  3. Multiphoton double ionization of Ar in intense extreme ultraviolet laser fields studied by shot-by-shot photoelectron spectroscopy.

    Science.gov (United States)

    Hikosaka, Y; Fushitani, M; Matsuda, A; Tseng, C-M; Hishikawa, A; Shigemasa, E; Nagasono, M; Tono, K; Togashi, T; Ohashi, H; Kimura, H; Senba, Y; Yabashi, M; Ishikawa, T

    2010-09-24

    Photoelectron spectroscopy has been performed to study the multiphoton double ionization of Ar in an intense extreme ultraviolet laser field (hν ∼ 21  eV, ∼ 5  TW/cm²), by using a free electron laser (FEL). Three distinct peaks identified in the observed photoelectron spectra clearly show that the double ionization proceeds sequentially via the formation of Ar(+): Ar+hν→Ar (+) + e⁻ and Ar²(+) + 2hν→Ar(+) + e⁻. Shot-by-shot recording of the photoelectron spectra allows simultaneous monitoring of FEL spectrum and the multiphoton process for each FEL pulse, revealing that the two-photon ionization from Ar(+) is significantly enhanced by intermediate resonances in Ar(+).

  4. Real-time single-shot electron bunch length measurements

    CERN Document Server

    Wilke, I; Gillespie, W A; Berden, G; Knippels, G M H; Meer, A F G

    2002-01-01

    Linear accelerators employed as drivers for X-ray free electron lasers (FELs) require relativistic electron bunch with sub-picosecond bunch length. Precise bunch length measurements are important for the tuning and operation of the FELs. Previously, we have demonstrated that electro-optic detection is a powerful technique for sub-picosecond electron bunch length measurements. In those experiments, the measured bunch length was the average of all electron bunches within a macropulse. Here, for the first time, we present the measurement of the length of individual electron bunches using a development of our previous technique. In this experiment, the longitudinal electron bunch shape is encoded electro-optically on to the frequency spectrum of a chirped laser pulse. Subsequently, the laser pulse is dispersed by a grating and the spectrum is imaged with a CCD camera. Single bunch measurements are achieved by using a nanosecond gated camera, and synchronizing the gate with both the electron bunch and the laser pu...

  5. Single-shot beam profile diagnostics for x-ray FEL's using gas fluorescence

    Science.gov (United States)

    Feng, Yiping; Zhu, Diling; Weninger, Clemens; Alonso-Mori, Roberto; Chollet, Matthieu; Damiani, Daniel S.; Glownia, James M.; Hastings, Jerome B.; Nelson, Silke; Song, Sanghoon; Robert, Aymeric

    2017-06-01

    We report experimental demonstration of capturing single-shot X-ray Free-electron Laser (FEL) beam profiles using gas fluorescence. The measurement was carried out at the Linac Coherent Light Source using 7 keV hard X-rays propagating through ambient air. The nitrogen fluorescence emitted upon the passage of the X-ray FEL beam were imaged using a highly sensitive optical setup, and there was sufficient optical yield that single-shot measurements were feasible. By taking two orthogonal and simultaneous images, the beam trajectory could be determined in a nearly non-invasive manner, and is best suited for photon energies in the soft X-ray regime, where such a diagnostic capability has been largely unavailable previously. The integrated intensity of the images could also serve as a non-invasive intensity monitor, complementary to current implementations of gas- and solidbased monitors. High repetition-rate Free-electron Lasers can greatly benefit from such a new diagnostic tool for eliminating potential thermal damages.

  6. Single-shot fluctuations in waveguided high-harmonic generation

    NARCIS (Netherlands)

    Goh, S.J.; Tao, Y.; van der Slot, Petrus J.M.; Bastiaens, Hubertus M.J.; Herek, Jennifer Lynn; Biedron, S.G.; Danailov, M.B.; Milton, S.V.; Boller, Klaus J.

    2015-01-01

    For exploring the application potential of coherent soft x-ray (SXR) and extreme ultraviolet radiation (XUV) provided by high-harmonic generation, it is important to characterize the central output parameters. Of specific importance are pulse-to-pulse (shot-to-shot) fluctuations of the high-harmonic

  7. Nanopillar formation from two-shot femtosecond laser ablation of poly-methyl methacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Baset, F.; Popov, K.; Villafranca, A.; Alshehri, A.M.; Guay, J.-M.; Ramunno, L.; Bhardwaj, V.R., E-mail: ravi.bhardwaj@uottawa.ca

    2015-12-01

    Highlights: • We studied morphological evolution and dynamics of two-pulse laser ablation in PMMA. • Nanopillar and volcanic eruption like structures are formed within the ablation crater. • Reflection of shockwave induced by the second laser pulse creates the structures. • Shockwave reflects from the boundary created by the first pulses. • Reflected shockwave causes density pinching in the middle of the ablation region. - Abstract: We present experimental and numerical studies on the morphological evolution and dynamics of femtosecond laser ablation of bulk poly-methyl methacrylate (PMMA) irradiated with a pair of pulses. We show that a nanopillar-like structure is formed in the middle of the ablation crater for pulse energies below single-shot ablation threshold. The nanopillar is ∼400 nm long, lies adjacent to a nanopore, and protrudes ∼150 nm above the sample surface. As the pulse energy is increased gradually, the nanopillar disappears and the nanopore inside the ablation crater becomes larger. At higher pulse energies, a volcanic eruption like structure appears in the middle of the crater whose size and height increases with energy. 2D molecular dynamics simulations reveal that a nanojet and other features observed at higher pulse energies can be formed when the reflection of a shockwave, induced by the second laser pulse, causes density pinching in the middle of the interaction region that rapidly pushes out molten material towards the surface. The shockwave is reflected from the cold boundaries of a modified region created by the first laser pulse.

  8. Single shot, double differential spectral measurements of inverse Compton scattering in the nonlinear regime

    Directory of Open Access Journals (Sweden)

    Y. Sakai

    2017-06-01

    Full Text Available Inverse Compton scattering (ICS is a unique mechanism for producing fast pulses—picosecond and below—of bright photons, ranging from x to γ rays. These nominally narrow spectral bandwidth electromagnetic radiation pulses are efficiently produced in the interaction between intense, well-focused electron and laser beams. The spectral characteristics of such sources are affected by many experimental parameters, with intense laser effects often dominant. A laser field capable of inducing relativistic oscillatory motion may give rise to harmonic generation and, importantly for the present work, nonlinear redshifting, both of which dilute the spectral brightness of the radiation. As the applications enabled by this source often depend sensitively on its spectra, it is critical to resolve the details of the wavelength and angular distribution obtained from ICS collisions. With this motivation, we present an experimental study that greatly improves on previous spectral measurement methods based on x-ray K-edge filters, by implementing a multilayer bent-crystal x-ray spectrometer. In tandem with a collimating slit, this method reveals a projection of the double differential angular-wavelength spectrum of the ICS radiation in a single shot. The measurements enabled by this diagnostic illustrate the combined off-axis and nonlinear-field-induced redshifting in the ICS emission process. The spectra obtained illustrate in detail the strength of the normalized laser vector potential, and provide a nondestructive measure of the temporal and spatial electron-laser beam overlap.

  9. Single-shot observation of growing streamers using an ultrafast camera

    International Nuclear Information System (INIS)

    Takahashi, E; Kato, S; Furutani, H; Sasaki, A; Kishimoto, Y; Takada, K; Matsumura, S; Sasaki, H

    2011-01-01

    A recently developed ultrafast camera that can acquire 10 8 frames per second was used to investigate positive streamer discharge. It enabled single-shot evaluation of streamer evolution without the need to consider shot-to-shot reproducibility. This camera was used to investigate streamers in argon. Growing branches, the transition when a streamer forms a return stroke, and related phenomena were clearly observed. (fast track communication)

  10. Single shot near edge x-ray absorption fine structure spectroscopy in the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Mantouvalou, I., E-mail: ioanna.mantouvalou@tu-berlin.de; Witte, K.; Martyanov, W.; Jonas, A.; Grötzsch, D.; Kanngießer, B. [Institute for Optics and Atomic Physics, Technical University of Berlin, D-10623 Berlin (Germany); Streeck, C. [Physikalisch-Technische Bundesanstalt (PTB), D-10587 Berlin (Germany); Löchel, H.; Rudolph, I.; Erko, A. [Helmholtz-Zentrum Berlin, D-14109 Berlin (Germany); Stiel, H. [Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, D-12489 Berlin (Germany)

    2016-05-16

    With the help of adapted off-axis reflection zone plates, near edge X-ray absorption fine structure spectra at the C and N K-absorption edge have been recorded using a single 1.2 ns long soft X-ray pulse. The transmission experiments were performed with a laser-produced plasma source in the laboratory rendering time resolved measurements feasible independent on large scale facilities. A resolving power of E/ΔE ∼ 950 at the respective edges could be demonstrated. A comparison of single shot spectra with those collected with longer measuring time proves that all features of the used reference samples (silicon nitrate and polyimide) can be resolved in 1.2 ns. Hence, investigations of radiation sensitive biological specimen become possible due to the high efficiency of the optical elements enabling low dose experiments.

  11. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  12. Laser Shot Peening Final Report CRADA No. TC-02059-03

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hackel, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This was a collaborative effort between The Regents of the University of California, Lawrence Livermore National Laboratory (LLNL) and Metal Improvement Company, Inc. (MIC), to further develop the laser shot peening technology. This project had an emphasis on laser development and government and military applications including DOE’s natural gas and oil technology program (NGOTP), Yucca Mountain Project (YMP), F-22 Fighter, etc.

  13. Light field driven streak-camera for single-shot measurements of the temporal profile of XUV-pulses from a free-electron laser; Lichtfeld getriebene Streak-Kamera zur Einzelschuss Zeitstrukturmessung der XUV-Pulse eines Freie-Elektronen Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Fruehling, Ulrike

    2009-10-15

    The Free Electron Laser in Hamburg (FLASH) is a source for highly intense ultra short extreme ultraviolet (XUV) light pulses with pulse durations of a few femtoseconds. Due to the stochastic nature of the light generation scheme based on self amplified spontaneous emission (SASE), the duration and temporal profile of the XUV pulses fluctuate from shot to shot. In this thesis, a THz-field driven streak-camera capable of single pulse measurements of the XUV pulse-profile has been realized. In a first XUV-THz pump-probe experiment at FLASH, the XUV-pulses are overlapped in a gas target with synchronized THz-pulses generated by a new THz-undulator. The electromagnetic field of the THz light accelerates photoelectrons produced by the XUV-pulses with the resulting change of the photoelectron momenta depending on the phase of the THz field at the time of ionisation. This technique is intensively used in attosecond metrology where near infrared streaking fields are employed for the temporal characterisation of attosecond XUV-Pulses. Here, it is adapted for the analysis of pulse durations in the few femtosecond range by choosing a hundred times longer far infrared streaking wavelengths. Thus, the gap between conventional streak cameras with typical resolutions of hundreds of femtoseconds and techniques with attosecond resolution is filled. Using the THz-streak camera, the time dependent electric field of the THz-pulses was sampled in great detail while on the other hand the duration and even details of the time structure of the XUV-pulses were characterized. (orig.)

  14. Study of anti-laser irradiation performance of shot-peened 40CrNiMoA alloy steel

    International Nuclear Information System (INIS)

    Liu, Zhanwei; Wu, Ningning; Huang, Xianfu; Xie, Huimin; Lv, Xintao; He, Guang

    2012-01-01

    In this paper, shot-peening treatment was introduced to reinforce an alloy surface to protect it from laser irradiation, and experiments were carried out on 40CrNiMoA alloy steel. Macro-mechanical properties were studied and compared before and after both shot-peening and laser irradiation by conducting tensile and hardness measurements. Experimental results showed that the shot-peened alloy showed better mechanical properties after laser irradiation when compared to the alloy without shot-peening treatment. The enhanced ability of the shot-peened alloy for anti-laser irradiation was explained as due to the large residual compressive stress distributions over the shot-peening layer greatly reducing the thermal shock effect introduced by the laser. On the other hand, the growth of microstructures in specific shape absorbed the thermal energy during irradiation, giving a higher probability for the alloy to resist damage.

  15. Multiple shot laser-induced damage in dielectrics with absorbing inclusions

    International Nuclear Information System (INIS)

    Nathan, V.

    1996-01-01

    A formula is derived to predict the temperature distribution in a spherical absorbing inclusion embedded in a dielectric, when it is subjected to rectangular multiple laser shots. It is found that the temperature distribution is a complicated function of the radius of the impurity, laser intensity, number of shots, pulse duration, and time interval between pulses. Numerical calculations of the minimum number of shots (n min ) needed to raise the temperature of the impurity-host boundary to the melting point of the impurity are carried out for the case of ThO 2 in ThF 4 for several incident laser intensities (I), pulsewidths (t p ), and time between pulses (t I ). The results show that for fixed values of t I /t p , I(n min t p ) 1/2 is approximately a constant. (orig.)

  16. XRD investigation of microstructure strengthening mechanism of shot peening on laser hardened 17-4PH

    International Nuclear Information System (INIS)

    Wang Zhou; Luan Weizhi; Huang Junjie; Jiang Chuanhai

    2011-01-01

    Highlights: → We analyzed the microstructure of shot peened component. → We estimated the domain size, the microstrain and dislocation density of specimen via XRD profile method. → The domain size increased and microstrain as well as dislocation density decreased with depth increasing. → The surface domain size decreased to nano-scale after shot peening treatment. → The surface dislocation density increased about one order magnitude after shot peening treatment. - Abstract: The influence of shot peening on microstructure of laser hardened 17-4PH was investigated by using X-ray diffraction profiles. The domain size, microstrain and dislocation in different depths were calculated via Voigt method and dislocation density calculation method according to Williamson's work. Two typical materials in laser hardened 17-4PH (matrix material and laser hardened material) and three families of crystalline planes ({1 1 0}, {2 0 0}, {2 1 1}) were chosen as research objects. Microstructural results from XRD investigation quantified the shot peening influence on microstrain, domain size and dislocation density in microstructure changed layer in these three plane diffraction directions. Results showed that shot peening was an efficient cold working method to alter microstructure in near surface region and microstructure strengthening mechanism of shot peening played an important role on improving the surface mechanical properties. In microstructure changed layer, the domain size increased and microstrain as well as dislocation density decreased with depth increasing, which led to the mechanical properties decrease with depth increasing. With increasing peening intensity from 0.2 mmA + 0.1 mmA to 0.5 mmA + 0.1 mmA, the depth of microstructure changed layer increased but the surface microstructure did not change, no matter in matrix material or laser hardened material. As laser hardened material had a stronger resistance against shot peening influence on microstructure, the

  17. Analysis and enhancement of 3D shape accuracy in a single-shot LIDAR sensor

    Science.gov (United States)

    Han, Munhyun; Choi, Gudong; Song, Minhyup; Seo, Hongseok; Mheen, Bongki

    2017-02-01

    The accuracy of timing jitter is of prime importance in the prevalent utilization of Light Detection and Ranging (LiDAR) technology for the real-time high-resolution three-dimensional (3D) image sensor, especially for relatively small object detection in various applications, such as in the fully automated car navigation and military surveillance. To assess the accuracy of timing, that is, the accuracy of the distance or three-dimensional shape, the standard deviation method can be used in the Time-of-Flight (ToF) LiDAR technology. While most timing jitter analyses are mainly based on a fiber-network or open space at a relatively short range distance, more accurate analyses are required to extract more information about the timing jitter at in a 3D image sensor long-range free space conditions for extended LiDAR-related applications. In this paper, utilizing a Single-Shot LiDAR System (SSLs) model with a 400 MHz wideband InGaAs Avalanche Photodiode and a 1550 nm 2 nsec full width at half maximum MOPA fiber laser, we analyzed the precise timing jitter for the implemented SSLs to characterize the measurement results. Additionally, we report the enhanced results for the resolution and precision in the given SSLs using the spline interpolation method from the measured results, and multiple-shot averaging (MSA). Finally, by adapting the proposed method to an implemented high resolution 3D LiDAR prototype, called the STUD LiDAR prototype, which can be understood as one kind of SSLs because it has a single source and a single detector as in a SSLs, we observed and analyzed the 3D resolution enhancement.

  18. Femtosecond Single-Shot Imaging of Nanoscale Ferromagnetic Order in Co/Pd Multilayers using Resonant X-ray Holography

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tianhan; Zhu, Diling; Benny Wu,; Graves, Catherine; Schaffert, Stefan; Rander, Torbjorn; Muller, leonard; Vodungbo, Boris; Baumier, Cedric; Bernstein, David P.; Brauer, Bjorn; Cros, Vincent; Jong, Sanne de; Delaunay, Renaud; Fognini, Andreas; Kukreja, Roopali; Lee, Sooheyong; Lopez-Flores, Victor; Mohanty, Jyoti; Pfau, Bastian; Popescu, 5 Horia

    2012-05-15

    We present the first single-shot images of ferromagnetic, nanoscale spin order taken with femtosecond x-ray pulses. X-ray-induced electron and spin dynamics can be outrun with pulses shorter than 80 fs in the investigated fluence regime, and no permanent aftereffects in the samples are observed below a fluence of 25 mJ/cm{sup 2}. Employing resonant spatially-muliplexed x-ray holography results in a low imaging threshold of 5 mJ/cm{sup 2}. Our results open new ways to combine ultrafast laser spectroscopy with sequential snapshot imaging on a single sample, generating a movie of excited state dynamics.

  19. Shot noise as a probe of spin-correlated transport through single atoms

    Science.gov (United States)

    Pradhan, S.; Fransson, J.

    2018-03-01

    We address the shot noise in the tunneling current through a local spin, pertaining to recent experiments on magnetic adatoms and single molecular magnets. We show that both uncorrelated and spin-correlated scattering processes contribute vitally to the noise spectrum. The spin-correlated scattering processes provide an additional contribution to the Landauer-Büttiker shot noise expression, accounting for correlations between the tunneling electrons and the localized spin moment. By calculating the Fano factor, we show that both super- and sub-Poissonian shot noise can be described within our approach. Our theory provides transparent insights into noise spectroscopy, consistent with recent experiments using local probing techniques on magnetic atoms.

  20. Pulsed laser deposition of lysozyme: the dependence on shot numbers and the angular distribution

    DEFF Research Database (Denmark)

    Constantinescu, C.; Matei, A.; Schou, Jørgen

    2013-01-01

    . This was verified by matrix-assisted laser desorption ionization (MALDI) spectrometry of thin films deposited on silicon substrates. The deposition rate of lysozyme was found to decrease with the number of shots and was correlated with increasing thermal damage of the lysozyme. This was monitored by measurements...

  1. Laser Shot Peening System Final Report CRADA No. TC-1369-96

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Harris, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This CRADA project was established with a primary goal to develop a laser shot peening system which could operate at production throughput rates and produce the desired depth and intensity of induced shots. The first objective was to understand all parameters required for acceptable peening, including pulse energy, pulse temporal format, pulse spatial format, sample configuration and tamping mechanism. The next objective was to demonstrate the technique on representative samples and then on representative parts. The final objective was to implement the technology into a meaningful industrial peen.

  2. Single shot imaging through turbid medium and around corner using coherent light

    Science.gov (United States)

    Li, Guowei; Li, Dayan; Situ, Guohai

    2018-01-01

    Optical imaging through turbid media and around corner is a difficult challenge. Even a very thin layer of a turbid media, which randomly scatters the probe light, can appear opaque and hide any objects behind it. Despite many recent advances, no current method can image the object behind turbid media with single record using coherent laser illumination. Here we report a method that allows non-invasive single-shot optical imaging through turbid media and around corner via speckle correlation. Instead of being as an obstacle in forming diffractionlimited images, speckle actually can be a carrier that encodes sufficient information to imaging through visually opaque layers. Optical imaging through turbid media and around corner is experimentally demonstrated using traditional imaging system with the aid of iterative phase retrieval algorithm. Our method require neither scan of illumination nor two-arm interferometry or long-time exposure in acquisition, which has new implications in optical sensing through common obscurants such as fog, smoke and haze.

  3. Comparative Study on the Efficacy of Two Regimens of Single-Shot ...

    African Journals Online (AJOL)

    ... mother by increasing self esteem and improving bonding with the baby. Objective: To assess and compare the satisfaction and efficacy of two regimens of single-shot spinal blocks for the relief of labor pain in women who present in active phase of labour. Design: A prospective randomised single-blind observational study

  4. The single-shot opto-digitizer; L'optoechantillonneur monocoup

    Energy Technology Data Exchange (ETDEWEB)

    Nail, M.; Gibert, Ph. [CEA/DAM-Ile de France, Dept. de Conception et Realisation des Experimentations (DCRE), 91 - Bruyeres-le-Chatel (France); CEA/DAM-Ile de France, Dept. Laser Puissance, DLP, 91 - Bruyeres-Le-Chatel (France)

    2000-07-01

    Laser-plasma experiments need to measure signals provided either by X-ray, photonic or neutronic detector. The measurement should have 50 GHz bandwidth and up to several hundred of Giga-Hertz for sub picosecond plasmas. For this purpose, a 35 GHz single shot opto-digitizer (10 ps risetime) has been studied and built. The device is made up of a 50 ohms microstrip propagation line, periodically lined by 100 sampled gates. The propagation line is long enough to measure a 400 ps duration. The sampling rate is 250 Gsa/s (every 4 ps). The sampled gates are made with fast recombining photo-material and turn on by a subpicosecond laser pulse which is synchronized exactly with the analysed phenomena. Every gate is recording to a storing capacitor. After the recording, every capacitor charge is needed to built the signal that was displayed on the propagation line. The dynamic range of measurement is 47 for the entire device. The device can measure positive or negative signals from 1.5 to 70 Volts. To increase the bandwidth, two another kinds of opto-digitizer were studied: one is a buried stripline with 56 GHz band width, the other a 70 GHz coplanar transmission line. For the purpose of subpicosecond plasmas, a 30 coplanar waveguide opto-digitizer was studied. Characteristics are as followed: window of measurement 40 ps, sampling rate 1 ps, bandwidth 230 GHz. Finally, a bundle of optical fibers was used to propagate the laser beam on semiconductor gates. If the gates are lighted at the same time, i.e. if the optical fibers have the same length, we get a simultaneous addressing. By using different lengths of optical fibers, we can do a sequential addressing. So, the sampling rate becomes a combination of the distance between two adjacent sampled channels, and the difference in length of optical fibers. (author)

  5. Inversion recovery single-shot TurboFLASH for assessment of myocardial infarction at 3 Tesla.

    Science.gov (United States)

    Bauner, Kerstin U; Muehling, Olaf; Wintersperger, Bernd J; Winnik, Eva; Reiser, Maximilian F; Huber, Armin

    2007-06-01

    The aim of the study was to assess the diagnostic accuracy of imaging myocardial infarction with a single-shot inversion recovery turbofast low-angle shot (SS IR turboFLASH) sequence at 3.0 Tesla in comparison with an established segmented inversion recovery turboFLASH sequence at 1.5 Tesla. Fifteen patients with myocardial infarction were examined at a 1.5 Tesla magnetic resonance (MR) System (Avanto, Siemens, Medical Solutions) and at a 3.0 Tesla MR system (TIM Trio, Siemens, Medical Solutions). Imaging delayed enhancement was started 15 minutes after application of contrast material. A SS IR turboFLASH was performed at 3.0 Tesla and compared with a segmented IR turboFLASH sequence at 1.5 and at 3.0 Tesla. The IR turboFLASH sequence at 1.5 Tesla served as reference method. Infarct volumes, contrast/noise ratio (CNR) of infarcted and normal myocardium were compared with the reference method. The Single-Shot IR turboFLASH technique allows imaging 9 slices during a single breath-hold. The CNR between infarction and normal myocardium of the reference method was 6.4 at 1.5 Tesla. The mean value of CNR of the IR turboFLASH sequence was 7.3 at 3.0 Tesla for the single-shot technique and 14.1 at 3.0 Tesla for the segmented technique. No significant difference was found for the CNR values of the reference technique at 1.5 Tesla and the single-shot technique at 3.0 Tesla, however for the comparison of the segmented technique at 1.5 and at 3 Tesla (P = 0.0001). The correlation coefficients of the infarct volumes, determined with the Single-Shot IR turboFLASH and the segmented IR turboFLASH technique at 3.0 compared with the reference method, were r = 0.95 (P < 0.0001) and r = 0.95 (P < 0.0001). The loss of CNR, which is caused by replacement of the segmented technique by the single-shot technique, is completely compensated by the approximately 2-fold CNR increase at the higher field strength. The IR turboFLASH technique at 3.0 Tesla IR can be used as a single-shot technique

  6. Shot-noise dominant regime of a nanoparticle in a laser beam

    Science.gov (United States)

    Zhong, Changchun; Robicheaux, Francis

    2017-04-01

    The technique of laser levitation of nanoparticles has become increasingly promising in the study of cooling and controlling mesoscopic quantum systems. Unlike a mechanical system, the levitated nanoparticle is less exposed to thermalization and decoherence due to the absence of direct contact with a thermal environment. In ultrahigh vacuum, the dominant source of decoherence comes from the unavoidable photon recoil from the optical trap which sets an ultimate bound for the control of levitated systems. In this paper, we study the shot noise heating and the parametric feedback cooling of an optically trapped anisotropic nanoparticle in the laser shot noise dominant regime. The rotational trapping frequency and shot noise heating rate have a dependence on the shape of the trapped particle. For an ellipsoidal particle, the ratio of the axis lengths and the overall size controls the shot noise heating rate relative to the rotational frequency. For a near spherical nanoparticle, the effective heating rate for the rotational degrees of freedom is smaller than that for translation suggesting that the librational ground state may be easier to achieve than the vibrational ground state.

  7. Single-shot self-interference incoherent digital holography using off-axis configuration.

    Science.gov (United States)

    Hong, Jisoo; Kim, Myung K

    2013-12-01

    We propose a single-shot incoherent holographic imaging technique that adopts self-interference incoherent digital holography (SIDH) with slight tilt of the plane mirror in the optical configuration. The limited temporal coherence length of the illumination leads the guide-star hologram of the proposed system to have a Gaussian envelope of elliptical ring shape. The observation shows that the reconstruction by cross correlation with the guide-star hologram achieves better quality than the usual propagation methods. Experimentally, we verify that the hologram and 3D reconstruction can be implemented incoherently with the proposed single-shot off-axis SIDH.

  8. X-Ray Emission Spectrometer Design with Single-Shot Pump-Probe and Resonant Excitation Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Spoth, Katherine; /SUNY, Buffalo /SLAC

    2012-08-28

    Core-level spectroscopy in the soft X-ray regime is a powerful tool for the study of chemical bonding processes. The ultrafast, ultrabright X-ray pulses generated by the Linac Coherent Light Source (LCLS) allow these reactions to be studied in greater detail than ever before. In this study, we investigated a conceptual design of a spectrometer for the LCLS with imaging in the non-dispersive direction. This would allow single-shot collection of X-ray emission spectroscopy (XES) measurements with varying laser pump X-ray probe delay or a variation of incoming X-ray energy over the illuminated area of the sample. Ray-tracing simulations were used to demonstrate how the components of the spectrometer affect its performance, allowing a determination of the optimal final design. These simulations showed that the spectrometer's non-dispersive focusing is extremely sensitive to the size of the sample footprint; the spectrometer is not able to image a footprint width larger than one millimeter with the required resolution. This is compatible with a single shot scheme that maps out the laser pump X-ray probe delay in the non-dispersive direction as well as resonant XES applications at normal incidence. However, the current capabilities of the Soft X-Ray (SXR) beamline at the LCLS do not produce the required energy range in a small enough sample footprint, hindering the single shot resonant XES application at SXR for chemical dynamics studies at surfaces. If an upgraded or future beamline at LCLS is developed with lower monochromator energy dispersion the width can be made small enough at the required energy range to be imaged by this spectrometer design.

  9. Quantitative single shot and spatially resolved plasma wakefield diagnostics

    CERN Document Server

    Kasim, Muhammad Firmansyah; Ceurvorst, Luke; Levy, Matthew C; Ratan, Naren; Sadler, James; Bingham, Robert; Burrows, Philip N; Trines, Raoul; Wing, Matthew; Norreys, Peter

    2015-01-01

    Diagnosing plasma conditions can give great advantages in optimizing plasma wakefield accelerator experiments. One possible method is that of photon acceleration. By propagating a laser probe pulse through a plasma wakefield and extracting the imposed frequency modulation, one can obtain an image of the density modulation of the wakefield. In order to diagnose the wakefield parameters at a chosen point in the plasma, the probe pulse crosses the plasma at oblique angles relative to the wakefield. In this paper, mathematical expressions relating the frequency modulation of the laser pulse and the wakefield density profile of the plasma for oblique crossing angles are derived. Multidimensional particle-in-cell simulation results presented in this paper confirm that the frequency modulation profiles and the density modulation profiles agree to within 10%. Limitations to the accuracy of the measurement are discussed in this paper. This technique opens new possibilities to quantitatively diagnose the plasma wakefie...

  10. Shot noise as a probe of spin-polarized transport through single atoms

    DEFF Research Database (Denmark)

    Burtzlaff, Andreas; Weismann, Alexander; Brandbyge, Mads

    2015-01-01

    Single atoms on Au(111) surfaces have been contacted with the Au tip of a low temperature scanning tunneling microscope. The shot noise of the current through these contacts has been measured up to frequencies of 120 kHz and Fano factors have been determined to characterize the transport channels...

  11. Single-shot two-dimensional full-range optical coherence tomography achieved by dispersion control

    NARCIS (Netherlands)

    Witte, S.; Baclayon, M.; Peterman, E.J.G.; Toonen, R.F.G.; Mansvelder, H.D.; Groot, M.L.

    2009-01-01

    We present a full-range Fourier-domain optical coherence tomography (OCT) system that is capable of acquiring two-dimensional images of living tissue in a single shot. By using line illumination of the sample in combination with a two-dimensional imaging spectrometer, 1040 depth scans are performed

  12. A second-order autocorrelator for single-shot measurement of ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    mental and second-harmonic frequency respectively, and 2α is the crossover angle of the beams inside the ... dispersion (GVD) effects in the crystal and spatial resolution of the imaging system. In the case ... Figure 3a shows the image of SH radiation from the KDP crystal corresponding to the single- shot operation of the ...

  13. Single-shot LIBS spectral quality for waste particles in open air

    NARCIS (Netherlands)

    Xia, H.; Bakker, M.C.M.

    2015-01-01

    This work investigates the ability of LIBS to produce quality spectra from small particles of concrete demolition waste using single-shot spectra collected in open air. The 2–8?mm materials are rounded river gravel, green glass shards, and plastic flakes. Considered are focal length, air, moisture,

  14. MR cholangiopancreatography of pancreaticobiliary diseases: Comparison of single-shot RARE and multislice HASTE sequences

    Energy Technology Data Exchange (ETDEWEB)

    Morrin, Martina M.; Farrell, Richard J.; McEntee, Gerry; MacMathuna, Padraic; Stack, John P.; Murrah, John G

    2000-11-01

    AIMS: We prospectively compared two breath-hold magnetic resonance cholangiopancreatography (MRCP) sequences: single-shot rapid acquisition with relaxation enhancement (RARE) and multislice half-Fourier acquisition single-shot turbo spin echo (HASTE) in imaging the pancreaticobiliary system. PATIENTS AND METHODS: The diagnostic accuracy of single-shot RARE and multislice HASTE was studied in 34 subjects who had undergone conventional cholangiopancreatography. Overall image quality, duct conspicuity, image artifact, signal intensity and contrast-to-noise ratios were assessed independently by two radiologists who were unaware of the underlying diagnosis. RESULTS: Both sequences had comparable diagnostic accuracy regarding a normal biliary system, choledocholithiasis, extra-hepatic and intra-hepatic strictures. Single-shot RARE was superior to multislice HASTE in diagnosing a normal pancreatic system, pancreatic and intrahepatic duct strictures, while providing significantly better image quality (mean {+-} SE 3.7 {+-} 0.07 vs 3.3 {+-} 0.08: P = 0.02) and significantly less image artifact (mean {+-} SE 3.6 {+-} 0.07 vs 3.2 {+-} 0.08:P = 0.01). Single-shot RARE provided significantly better duct conspicuity regarding the pancreatic duct within the body (2.7 {+-} 0.2 vs 2.1 {+-} 0.2: P = 0.003) and tail (2.4 {+-} 0.2 vs 1.6 {+-} 0.2;P = 0.0001), as well as the intrahepatic ducts (3.0 {+-} 0.1 vs 2.6 {+-} 0.1: P = 0.004) but there was no significant difference regarding the remainder of the biliary tree. CONCLUSION: Single-shot RARE provides superior image quality, duct conspicuity with the added advantage of less image artifact and shorter acquisition time. However, volume averaging can cause common bile duct stones to be missed. Therefore, multislice HASTE sequences should still be acquired if choledocholithiasis is suspected. Larger studies are required to assess the diagnostic efficacy of single-shot RARE sequences in pancreatic duct and intra-hepatic duct disease

  15. Pulsed laser deposition of lysozyme: the dependence on shot numbers and the angular distribution

    Science.gov (United States)

    Constantinescu, C.; Matei, A.; Schou, J.; Canulescu, S.; Dinescu, M.

    2013-12-01

    The ejection of molecules from a pressed solid target of lysozyme induced by laser ablation in the UV-regime at a wavelength of 355 nm was investigated. The ablation studies were carried out in vacuum at a laser fluence of 2 J/cm2 for which a significant fraction of proteins remains intact. This was verified by matrix-assisted laser desorption ionization (MALDI) spectrometry of thin films deposited on silicon substrates. The deposition rate of lysozyme was found to decrease with the number of shots and was correlated with increasing thermal damage of the lysozyme. This was monitored by measurements of the optical reflectivity of dry lysozyme. The angular distribution of the mass deposition can be fitted well by Anisimov's hydrodynamic model. The total deposited yield over the entire hemisphere from direct laser ablation of lysozyme was estimated from this model and found to be three orders of magnitude less than the ablated mass.

  16. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Mo, M. Z., E-mail: mmo09@slac.stanford.edu; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; Makasyuk, I.; Edstrom, S.; McCormick, D.; Jobe, K.; Hast, C.; Glenzer, S. H.; Wang, X. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Sokolowski-Tinten, K. [Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, D-47048 Duisburg (Germany)

    2016-11-15

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.

  17. Speckle noise reduction in single-shot holographic two-wavelength contouring

    Science.gov (United States)

    Agour, Mostafa; Klattenhoff, Reiner; Falldorf, Claas; Bergmann, Ralf B.

    2017-05-01

    We present an experimental configuration that enables form measurement from a single-shot camera exposure. It combines two-wavelength contouring with spatial multiplexing synthetic-aperture digital holography. The synthetic-aperture in this work is formed by simultaneously illuminating the test object from two different angles. The two illumination directions and the two-wavelength contouring result in four holograms which are spatially multiplexed on a single camera target avoiding unwanted cross-interference between them by means of coherence gating. In contrast to standard holographic contouring methods, the proposed technique reduces speckle decorrelation noise and enables single shot form measurement. To demonstrate this technique, the shape of a micro cold drawing part is determined.

  18. Laser Peening and Shot Peening Effects on Fatigue Life and Surface Roughness of Friction Stir Welded 7075-T7351 Aluminum

    Science.gov (United States)

    Hatamleh, Omar; Lyons, Jed; Forman, Royce

    2006-01-01

    The effects of laser peening, shot peening, and a combination of both on the fatigue life of Friction Stir Welds (FSW) was investigated. The fatigue samples consisted of dog bone specimens and the loading was applied in a direction perpendicular to the weld direction. Several laser peening conditions with different intensities, durations, and peening order were tested to obtain the optimum peening parameters. The surface roughness resulting from various peening techniques was assessed and characterized. The results indicate a significant increase in fatigue life using laser peening compared to shot peened versus their native welded specimens.

  19. Shot-noise-limited optical Faraday polarimetry with enhanced laser noise cancelling

    International Nuclear Information System (INIS)

    Li, Jiaming; Luo, Le; Carvell, Jeff; Cheng, Ruihua; Lai, Tianshu; Wang, Zixin

    2014-01-01

    We present a shot-noise-limited measurement of optical Faraday rotations with sub-ten-nanoradian angular sensitivity. This extremely high sensitivity is achieved by using electronic laser noise cancelling and phase sensitive detection. Specially, an electronic laser noise canceller with a common mode rejection ratio of over 100 dB was designed and built for enhanced laser noise cancelling. By measuring the Faraday rotation of ambient air, we demonstrate an angular sensitivity of up to 9.0×10 −9  rad/√(Hz), which is limited only by the shot-noise of the photocurrent of the detector. To date, this is the highest angular sensitivity ever reported for Faraday polarimeters in the absence of cavity enhancement. The measured Verdet constant of ambient air, 1.93(3)×10 −9 rad/(G cm) at 633 nm wavelength, agrees extremely well with the earlier experiments using high finesse optical cavities. Further, we demonstrate the applications of this sensitive technique in materials science by measuring the Faraday effect of an ultrathin iron film

  20. Damage in solids irradiated by a single shot of XUV free-electron laser: irreversible changes investigated using X-ray microdiffraction, atomic force microscopy and Nomarski optical microscopy

    Czech Academy of Sciences Publication Activity Database

    Pelka, J. B.; Sobierajski, R.; Klinger, D.; Paszkowicz, W.; Krzywinski, J.; Jurek, M.; Zymierska, D.; Wawro, A.; Petroutchik, A.; Juha, Libor; Hájková, Věra; Cihelka, Jaroslav; Chalupský, Jaromír; Burian, T.; Vyšín, Luděk; Toleikis, S.; Sokolowski-Tinten, K.; Stojanovic, N.; Zastrau, U.; London, R.; Hau-Riege, S.; Riekel, C.; Davies, R.; Burghammer, M.; Dynowska, E.; Szuszkiewicz, W.; Caliebe, W.; Nietubyc, R.

    2009-01-01

    Roč. 78, Suppl. 10 (2009), S46-S52 ISSN 0969-806X R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : XUV FEL * radiation damage * ablation * structure modifications * x-ray diffraction Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.149, year: 2009

  1. Algorithms for image recovery calculation in extended single-shot phase-shifting digital holography

    Science.gov (United States)

    Hasegawa, Shin-ya; Hirata, Ryo

    2018-02-01

    The single-shot phase-shifting method of image recovery using an inclined reference wave has the advantages of reducing the effects of vibration, being capable of operating in real time, and affording low-cost sensing. In this method, relatively low reference angles compared with that in the conventional method using phase shift between three or four pixels has been required. We propose an extended single-shot phase-shifting technique which uses the multiple-step phase-shifting algorithm and the corresponding multiple pixels which are the same as that of the period of an interference fringe. We have verified the theory underlying this recovery method by means of Fourier spectral analysis and its effectiveness by evaluating the visibility of the image using a high-resolution pattern. Finally, we have demonstrated high-contrast image recovery experimentally using a resolution chart. This method can be used in a variety of applications such as color holographic interferometry.

  2. Algorithms for image recovery calculation in extended single-shot phase-shifting digital holography

    Science.gov (United States)

    Hasegawa, Shin-ya; Hirata, Ryo

    2018-04-01

    The single-shot phase-shifting method of image recovery using an inclined reference wave has the advantages of reducing the effects of vibration, being capable of operating in real time, and affording low-cost sensing. In this method, relatively low reference angles compared with that in the conventional method using phase shift between three or four pixels has been required. We propose an extended single-shot phase-shifting technique which uses the multiple-step phase-shifting algorithm and the corresponding multiple pixels which are the same as that of the period of an interference fringe. We have verified the theory underlying this recovery method by means of Fourier spectral analysis and its effectiveness by evaluating the visibility of the image using a high-resolution pattern. Finally, we have demonstrated high-contrast image recovery experimentally using a resolution chart. This method can be used in a variety of applications such as color holographic interferometry.

  3. Single-Shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator

    Science.gov (United States)

    2016-01-11

    Single-shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator Philip Kranz1, Andreas Bengtsson1, Michaël Simoen1, Simon...Josephson Parametric Oscillator Philip Krantz1, Andreas Bengtsson1, Michaël Simoen1, Simon Gustavsson2, Vitaly Shumeiko1, W. D. Oliver2,3, C. M...2016) We propose and demonstrate a new read-out technique for a superconducting qubit by dispersively coupling it to a Josephson parametric

  4. Reliability Assessment of a Single-Shot System by Use of Screen Test Results

    Science.gov (United States)

    2018-02-01

    unlimited. NUWC Keyport #17-002. Reliability Assessment of a Single-Shot System by Use of Screen Test Results Abstract: Field reliability prediction...approach described here assumes that the defect density during testing takes the form of an exponential decay, although other mathematical functions can...be substituted for the exponential. In order to apply the decay rate function to a discrete pass/fail test scheme, the approach provides for

  5. Single-shot echo-planar imaging of multiple sclerosis: effects of varying echo time

    International Nuclear Information System (INIS)

    Wolansky, L.J.; Chong, S.; Liu, W.C.; Kang, E.; Simpson, S.W.; Karimi, S.; Akbari, H.

    1999-01-01

    Our aim was to determine the relative merits of short and long echo times (TE) with single-shot echo-planar imaging for imaging cerebral lesions such as multiple sclerosis. We examined seven patients with clinically definite multiple sclerosis were imaged at 1.5 T. Patients were scanned with spin-echo, single-shot echo-planar imaging, using TEs of 45, 75, 105, and 135 ms. Region of interest (ROI) measurements were performed on 36 lesions at or above the level of the corona radiata. The mean image contrast (IC) was highest (231.1) for a TE of 45 ms, followed by 75 ms (218.9), 105 ms (217.9), and 135 ms (191.6). When mean contrast-to-noise ratios (C/N) were compared, the value was again highest (29.7) for TE 45 ms, followed by 75 ms (28.9), 105 ms (28.5), and 135 ms (26.3). In a lesion-by-lesion comparison, TE 45 ms had the highest IC and C/N in the largest number of cases (50 % and 47.2 %, respectively). IC and C/N for TE 45 ms were superior to those of 75 ms in 64 % and 58 %, respectively. These results support the use of relatively short TEs for single-shot echo-planar imaging in the setting of cerebral lesions such as multiple sclerosis. (orig.) (orig.)

  6. Real-Time, Single-Shot Temporal Measurements of Short Electron Bunches, Terahertz CSR and FEL Radiation

    CERN Document Server

    Berden, G; Van der Meer, A F G

    2005-01-01

    Electro-optic detection of the Coulomb field of electron bunches is a promising technique for single-shot measurements of the bunch length and shape in the sub-picosecond time domain. This technique has been applied to the measurement of 50 MeV electron bunches in the FELIX free electron laser, showing the longitudinal profile of single bunches of around 650 fs FWHM [Phys. Rev. Lett. 93, 114802 (2004)]. The method is non-destructive and real-time, and therefore ideal for online monitoring of the longitudinal shape of single electron bunches. At FELIX we have used it for real-time optimization of sub-picosecond electron bunches. Electro-optic detection has also been used to measure the electric field profiles of far-infrared (or terahertz) optical pulses generated by the relativistic electrons. We have characterised the far-infrared output of the free electron laser, and more recently, we have measured the temporal profile of terahertz optical pulses generated at one of the bending magnets.

  7. Single-shot femtosecond-pulsed phase-shifting digital holography.

    Science.gov (United States)

    Kakue, Takashi; Itoh, Seiya; Xia, Peng; Tahara, Tatsuki; Awatsuji, Yasuhiro; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2012-08-27

    Parallel phase-shifting digital holography is capable of three-dimensional measurement of a dynamically moving object with a single-shot recording. In this letter, we demonstrated a parallel phase-shifting digital holography using a single femtosecond light pulse whose central wavelength and temporal duration were 800 nm and 96 fs, respectively. As an object, we set spark discharge in atmospheric pressure air induced by applying a high voltage to between two electrodes. The instantaneous change in phase caused by the spark discharge was clearly reconstructed. The reconstructed phase image shows the change of refractive index of air was -3.7 × 10(-4).

  8. Observation of Quantum Jumps of a Single Quantum Dot Spin Using Submicrosecond Single-Shot Optical Readout

    Science.gov (United States)

    Delteil, Aymeric; Gao, Wei-bo; Fallahi, Parisa; Miguel-Sanchez, Javier; Imamoǧlu, Atac

    2014-03-01

    Single-shot readout of individual qubits is typically the slowest process among the elementary single- and two-qubit operations required for quantum information processing. Here, we use resonance fluorescence from a single-electron charged quantum dot to read out the spin-qubit state in 800 nanoseconds with a fidelity exceeding 80%. Observation of the spin evolution on longer time scales reveals quantum jumps of the spin state: we use the experimentally determined waiting-time distribution to characterize the quantum jumps.

  9. Integration of Heat Treatment with Shot Peening of 17-4 Stainless Steel Fabricated by Direct Metal Laser Sintering

    Science.gov (United States)

    AlMangour, Bandar; Yang, Jenn-Ming

    2017-11-01

    Direct metal laser sintering (DMLS) is a promising powder-based additive manufacturing process for fabrication of near-net-shape parts. However, the typically poor fatigue performance of DMLS parts must be addressed for use in demanding industrial applications. Post-treatment can be applied to enhance the performance of such components. Earlier attempts at inducing grain refinement through severe plastic deformation of part surfaces using shot peening improved the physical and mechanical properties of metals without chemical alteration. However, heat treatment can modify the surface-hardening effects attained by shot peening. Hence, we examined the feasibility of applying shot peening combined with heat treatment to improve the performance of DMLS-fabricated 17-4 stainless steel parts through microstructural evolution studies and hardness measurements. Compared to a specimen treated only by shot peening, the sample exposed to additional heat treatment showed increased hardness due to aging of the dominant phase.

  10. Anti-botulism single-shot vaccine using chitosan for protein encapsulation by simple coacervation.

    Science.gov (United States)

    Sari, Roger S; de Almeida, Anna Christina; Cangussu, Alex S R; Jorge, Edson V; Mozzer, Otto D; Santos, Hércules Otacílio; Quintilio, Wagner; Brandi, Igor Viana; Andrade, Viviane Aguiar; Miguel, Angelo Samir M; Sobrinho Santos, Eliane M

    2016-12-01

    The aim of the present study was to compare the potency and safety of vaccines against Clostridium botulinum (C. botulinum) type C and D formulated with chitosan as controlled release matrix and vaccines formulated in conventional manner using aluminum hydroxide. Parameters were established for the development of chitosan microspheres, using simple coacervation to standardize the use of this polymer in protein encapsulation for vaccine formulation. To formulate a single shot vaccine inactivated antigens of C. botulinum type C and D were used with original toxin titles equal to 5.2 and 6.2 log LD50/ml, respectively. For each antigen a chitosan based solution of 50 mL was prepared. Control vaccines were formulated by mixing toxoid type C and D with aluminum hydroxide [25% Al(OH) 3 , pH 6.3]. The toxoid sterility, innocuity and potency of vaccines were evaluated as stipulated by MAPA-BRASIL according to ministerial directive no. 23. Encapsulation efficiency of BSA in chitosan was 32.5-40.37%, while that the encapsulation efficiency to toxoid type C was 41,03% (1.94 mg/mL) and of the toxoid type D was 32.30% (1.82 mg/mL). The single shot vaccine formulated using chitosan for protein encapsulation through simple coacervation showed potency and safety similar to conventional vaccine currently used in Brazilian livestock (10 and 2 IU/mL against C. botulinum type C and D, respectively). The present work suggests that our single shot vaccine would be a good option as a cattle vaccine against these C. botulinum type C and D. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Partial Fourier techniques in single-shot cross-term spatiotemporal encoded MRI.

    Science.gov (United States)

    Zhang, Zhiyong; Frydman, Lucio

    2018-03-01

    Cross-term spatiotemporal encoding (xSPEN) is a single-shot approach with exceptional immunity to field heterogeneities, the images of which faithfully deliver 2D spatial distributions without requiring a priori information or using postacquisition corrections. xSPEN, however, suffers from signal-to-noise ratio penalties due to its non-Fourier nature and due to diffusion losses-especially when seeking high resolution. This study explores partial Fourier transform approaches that, acting along either the readout or the spatiotemporally encoded dimensions, reduce these penalties. xSPEN uses an orthogonal (e.g., z) gradient to read, in direct space, the low-bandwidth (e.g., y) dimension. This substantially changes the nature of partial Fourier acquisitions vis-à-vis conventional imaging counterparts. A suitable theoretical analysis is derived to implement these procedures, along either the spatiotemporally or readout axes. Partial Fourier single-shot xSPEN images were recorded on preclinical and human scanners. Owing to their reduction in the experiments' acquisition times, this approach provided substantial sensitivity gains vis-à-vis previous implementations for a given targeted in-plane resolution. The physical origins of these gains are explained. Partial Fourier approaches, particularly when implemented along the low-bandwidth spatiotemporal dimension, provide several-fold sensitivity advantages at minimal costs to the execution and processing of the single-shot experiments. Magn Reson Med 79:1506-1514, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  12. Single-shot secure quantum network coding on butterfly network with free public communication

    Science.gov (United States)

    Owari, Masaki; Kato, Go; Hayashi, Masahito

    2018-01-01

    Quantum network coding on the butterfly network has been studied as a typical example of quantum multiple cast network. We propose a secure quantum network code for the butterfly network with free public classical communication in the multiple unicast setting under restricted eavesdropper’s power. This protocol certainly transmits quantum states when there is no attack. We also show the secrecy with shared randomness as additional resource when the eavesdropper wiretaps one of the channels in the butterfly network and also derives the information sending through public classical communication. Our protocol does not require verification process, which ensures single-shot security.

  13. Deconvolution single shot multibox detector for supermarket commodity detection and classification

    Science.gov (United States)

    Li, Dejian; Li, Jian; Nie, Binling; Sun, Shouqian

    2017-07-01

    This paper proposes an image detection model to detect and classify supermarkets shelves' commodity. Based on the principle of the features directly affects the accuracy of the final classification, feature maps are performed to combine high level features with bottom level features. Then set some fixed anchors on those feature maps, finally the label and the position of commodity is generated by doing a box regression and classification. In this work, we proposed a model named Deconvolutiuon Single Shot MultiBox Detector, we evaluated the model using 300 images photographed from real supermarket shelves. Followed the same protocol in other recent methods, the results showed that our model outperformed other baseline methods.

  14. Experimental capabilities of 0.4 PW, 1 shot/min Scarlet laser facility for high energy density science.

    Science.gov (United States)

    Poole, P L; Willis, C; Daskalova, R L; George, K M; Feister, S; Jiang, S; Snyder, J; Marketon, J; Schumacher, D W; Akli, K U; Van Woerkom, L; Freeman, R R; Chowdhury, E A

    2016-06-10

    We report on the recently completed 400 TW upgrade to the Scarlet laser at The Ohio State University. Scarlet is a Ti:sapphire-based ultrashort pulse system that delivers >10  J in 30 fs pulses to a 2 μm full width at half-maximum focal spot, resulting in intensities exceeding 5×1021  W/cm2. The laser fires at a repetition rate of once per minute and is equipped with a suite of on-demand and on-shot diagnostics detailed here, allowing for rapid collection of experimental statistics. As part of the upgrade, the entire laser system has been redesigned to facilitate consistent, characterized high intensity data collection at high repetition rates. The design and functionality of the laser and target chambers are described along with initial data from commissioning experimental shots.

  15. Full report of laser doppler velocimetry (Het-V) data, results , and analysis for pRad shot 0632

    Energy Technology Data Exchange (ETDEWEB)

    Tupa, Dale [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tainter, Amy Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-21

    This was a collaborative shot with AWE investigators Paul Willis-Patel, David Bell, Seth Grant, David Tarr, and James Richley. The shot was assembled in Los Alamos, after which David Bell set up the probe holder and finalized the alignment. The probe holder location and configuration was modified from previous years to make room for the laser illuminated visible imaging diagnostic. The LANL pRad PDV team was Dale Tupa, Amy Tainter, and Patrick Medina. This shot had three PDV probes: one aimed at the center, one aimed at a feature, one aimed at the reverse side of the shot. The shot also had 9 points of a spectroscopy diagnostic. The pRad team helped set up and field the spectroscopy, but did not help with any data analysis. (The support documentation for the PDV results includes a timing map for the spectroscopy.) Please direct questions on the velocimetry to Dale Tupa or Amy Tainter. The shot radiographs were classified, but the data from the optical diagnostics are not.

  16. Single-Shot Quantum Nondemolition Detection of Individual Itinerant Microwave Photons

    Science.gov (United States)

    Besse, Jean-Claude; Gasparinetti, Simone; Collodo, Michele C.; Walter, Theo; Kurpiers, Philipp; Pechal, Marek; Eichler, Christopher; Wallraff, Andreas

    2018-04-01

    Single-photon detection is an essential component in many experiments in quantum optics, but it remains challenging in the microwave domain. We realize a quantum nondemolition detector for propagating microwave photons and characterize its performance using a single-photon source. To this aim, we implement a cavity-assisted conditional phase gate between the incoming photon and a superconducting artificial atom. By reading out the state of this atom in a single shot, we reach an external (internal) photon-detection fidelity of 50% (71%), limited by transmission efficiency between the source and the detector (75%) and the coherence properties of the qubit. By characterizing the coherence and average number of photons in the field reflected off the detector, we demonstrate its quantum nondemolition nature. We envisage applications in generating heralded remote entanglement between qubits and for realizing logic gates between propagating microwave photons.

  17. Single filament semiconductor laser

    International Nuclear Information System (INIS)

    Botez, D.

    1980-01-01

    A semiconductor laser comprising: a body of semiconductor material including a substrate having a surface and a pair of spaced, substantially parallel dove-tailed shaped grooves in said surface, said body having a pair of end surfaces between which said grooves extend, said end surfaces being reflective to light with at least one of said end surfaces being partially transparent to light a first epitaxial layer over said surface of the substrate and the surfaces of the grooves, said first epitaxial layer having a flat surface portion over the portion of the substrate surface between the grooves, a thin second epitaxial layer over said first epitaxial layer, a third epitaxial layer over said second epitaxial layer, said first and third epitaxial layers being of opposite conductivity types and the second epitaxial layer being the active recombination region of the laser with the light being generated therein in the vicinity of the portion which is over the flat surface portion of the first epitaxial layer, and a pair of contacts on said body with one contact being over said third epitaxial body and the other being on said substrate

  18. Feasibility study of a single-shot 3D electron bunch shape monitor with an electro-optic sampling technique

    Directory of Open Access Journals (Sweden)

    Yuichi Okayasu

    2013-05-01

    Full Text Available We developed a three-dimensional electron bunch charge distribution (3D-BCD monitor with single-shot detection, and a spectral decoding based electro-optic (EO sampling technique for a nondestructive monitor enables real-time reconstruction of the three-dimensional distribution of a bunch charge. We realized three goals by simultaneously probing a number of Pockels EO crystals that surround the electron beam axis with hollow and radial polarized laser pulses. First, we performed a feasibility test as a simple case of a 3D-BCD monitor probing two ZnTe crystals as EO detectors installed on the opposite angle to the electron beam axis and confirmed that we simultaneously obtained both EO signals. Since the adopted hollow probe laser pulse is not only radially polarized but also temporally shifted azimuthally, some disorders in the radial polarization distribution of such a laser pulse were numerically analyzed with a plane-wave expansion method. Based on the above investigations, the 3D-BCD monitor is feasible both in experimental and numerical estimations. Furthermore, we previously developed a femtosecond response organic crystal as a Pockels EO detector and a broadband probe laser (≥350  nm in FWHM; the 3D-BCD monitor realizes 30- to 40-fs (FWHM temporal resolution. Eventually, the monitor is expected to be equipped in such advanced accelerators as XFEL to measure and adjust the electron bunch charge distribution in real time. The 3D-BCD measurement works as a critical tool to provide feedback to seeded FELs.

  19. Single transverse mode protein laser

    Science.gov (United States)

    Dogru, Itir Bakis; Min, Kyungtaek; Umar, Muhammad; Bahmani Jalali, Houman; Begar, Efe; Conkar, Deniz; Firat Karalar, Elif Nur; Kim, Sunghwan; Nizamoglu, Sedat

    2017-12-01

    Here, we report a single transverse mode distributed feedback (DFB) protein laser. The gain medium that is composed of enhanced green fluorescent protein in a silk fibroin matrix yields a waveguiding gain layer on a DFB resonator. The thin TiO2 layer on the quartz grating improves optical feedback due to the increased effective refractive index. The protein laser shows a single transverse mode lasing at the wavelength of 520 nm with the threshold level of 92.1 μJ/ mm2.

  20. Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC.

    Directory of Open Access Journals (Sweden)

    Zachary F Phillips

    Full Text Available We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification-an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC, is a single-shot variant of Differential Phase Contrast (DPC, which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps for various in vitro cell samples and c. elegans in a micro-fluidic channel.

  1. Truly work-like work extraction via a single-shot analysis.

    Science.gov (United States)

    Aberg, Johan

    2013-01-01

    The work content of non-equilibrium systems in relation to a heat bath is often analysed in terms of expectation values of an underlying random work variable. However, when optimizing the expectation value of the extracted work, the resulting extraction process is subject to intrinsic fluctuations, uniquely determined by the Hamiltonian and the initial distribution of the system. These fluctuations can be of the same order as the expected work content per se, in which case the extracted energy is unpredictable, thus intuitively more heat-like than work-like. This raises the question of the 'truly' work-like energy that can be extracted. Here we consider an alternative that corresponds to an essentially fluctuation-free extraction. We show that this quantity can be expressed in terms of a one-shot relative entropy measure introduced in information theory. This suggests that the relations between information theory and statistical mechanics, as illustrated by concepts like Maxwell's demon, Szilard engines and Landauer's principle, extends to the single-shot regime.

  2. Single-shot readout of multiple nuclear spin qubits in diamond under ambient conditions

    Science.gov (United States)

    Jacques, Vincent

    2013-03-01

    Nuclear spins are attractive candidates for solid-state quantum information storage and processing owing to their extremely long coherence time. However, since this appealing property results from a high level of isolation from the environment, it remains a challenging task to polarize, manipulate and readout with high fidelity individual nuclear spins. A promising approach to overcome this limitation consists in utilizing an ancillary single electronic spin to detect and control remote nuclear spins coupled by hyperfine interaction. In this talk, I will show how the electronic spin of a single Nitrogen-Vacancy (NV) defect in diamond can be used as a robust platform to observe the real-time evolution of surrounding single nuclear spins under ambient conditions. Using a diamond sample with a natural abundance of 13C isotopes, we first demonstrate high fidelity initialization and single-shot readout of an individual 13C nuclear spin. By including the intrinsic 14N nuclear spin of the NV defect in the quantum register, we then report the simultaneous observation of quantum jumps linked to both nuclear spin species, providing an efficient initialization of the two qubits. These results open up new avenues for diamond-based quantum information processing (QIP) including active feedback in quantum error correction protocols and tests of quantum correlations with solid-state single spins at room temperature.

  3. Fast Detection of Airports on Remote Sensing Images with Single Shot MultiBox Detector

    Science.gov (United States)

    Xia, Fei; Li, HuiZhou

    2018-01-01

    This paper introduces a method for fast airport detection on remote sensing images (RSIs) using Single Shot MultiBox Detector (SSD). To our knowledge, this could be the first study which introduces an end-to-end detection model into airport detection on RSIs. Based on the common low-level features between natural images and RSIs, a convolution neural network trained on large amounts of natural images was transferred to tackle the airport detection problem with limited annotated data. To deal with the specific characteristics of RSIs, some related parameters in the SSD, such as the scales and layers, were modified for more accurate and rapider detection. The experiments show that the proposed method could achieve 83.5% Average Recall at 8 FPS on RSIs with the size of 1024*1024. In contrast to Faster R-CNN, an improvement on AP and speed could be obtained.

  4. Single-shot parallel full range complex Fourier-domain optical coherence tomography

    International Nuclear Information System (INIS)

    Huang Bingjie; Bu Peng; Nan Nan; Wang Xiangzhao

    2011-01-01

    We present a method of parallel full range complex Fourier-domain optical coherence tomography (FDOCT) that is capable of acquiring an artifacts-free two-dimensional (2-D) cross-sectional image, i.e. a full range B-scan tomogram, by a single shot of 2-D CCD camera. This method is based on a spatial carrier technique, in which the spatial carrier-frequency is instantaneously introduced into the 2-D spectral interferogram registered in parallel FDOCT by using a grating-generated reference beam. The spatial-carrier-contained 2-D spectral interferogram is processed through Fourier transformation to obtain a complex 2-D spectral interferogram. From the 2-D complex spectral interferomgram, a full range B-scan tomogram is reconstructed. The principle of our method is confirmed by imaging an onion sample.

  5. Kinematic MRI using short TR single shot fast spin echo (SSFSE) in evaluating swallowing

    International Nuclear Information System (INIS)

    Isogai, Satoshi; Takehara, Yasuo; Isoda, Haruo; Kodaira, Nami; Masunaga, Hatsuko; Ozawa, Fukujirou; Kaneko, Masao; Nozaki, Atsushi; Kabasawa, Hiroyuki

    1999-01-01

    The utility of short TR single shot fast spin echo (SSFSE) MR imaging for evaluating swallowing was determined. Five healthy volunteers underwent kinematic MR imaging of swallowing with a 1.5 T MR scanner using the short TR (300 ms) SSFSE sequence. Twenty phases of sagittal sections were acquired within 6 sec, where the temporal resolution was 300 ms. For oral contrast medium, we used prune yogurt juice with Fe added. The image contrast of short TR SSFSE was found to be somewhere like that of T1-weighted images. In all cases, both the buccal and pharyngeal stages of swallowing were successfully depicted. The Fe-added prune yogurt juice performed as a positive contrast medium and helped determine anatomical structures in the buccal stage. Short TR (300 ms) SSFSE was useful in evaluating swallowing. The combined use of Fe-added prune yogurt juice was helpful in enhancing the surface of the oropharynx. (author)

  6. Single-shot in-line digital holography without twin image

    Science.gov (United States)

    Nomura, Takanori

    2018-01-01

    In-line digital holography is conventional but still attractive because of its simple optical setup. In general, sequential phase-shifting technique is mandatory to remove twin-image which makes the reconstructed image quality low. However, sequential phase-shifting technique requires multiple recording. Multiple recording means that it is not suitable for a dynamic phenomenon. In this paper, two kinds of a single-shot in-line digital holography without twin-image using a diffused illumination are presented. One is a generalized phase-shifting digital holography and the other is a computational removal of twin-image. The ideas and their experimental results are given to confirm the feasibility.

  7. Hyperspectral interferometry for single-shot absolute measurement of 3-D shape and displacement fields

    Directory of Open Access Journals (Sweden)

    Ruiz P. D.

    2010-06-01

    Full Text Available We propose a method that we call Hyperspectral Interferometry (HSI to resolve the 2π phase unwrapping problem in the analysis of interferograms recorded with a narrow-band light source. By using a broad-band light source and hyperspectral imaging system, a set of interferograms at different wavenumbers are recorded simultaneously on a high resolution image sensor. These are then assembled to form a three-dimensional intensity distribution. By Fourier transformation along the wavenumber axis, an absolute optical path difference is obtained for each pixel independently of the other pixels in the field of view. As a result, interferograms with spatially distinct regions are analysed as easily as continuous ones. The approach is illustrated with a HSI system to measure 3-D profiles of optically smooth or rough surfaces. Compared to existing profilometers able to measure absolute path differences, the single shot nature of the approach provides greater immunity from environmental disturbance.

  8. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator

    Science.gov (United States)

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michaël; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    2016-01-01

    We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing. PMID:27156732

  9. Compressive sensing sectional imaging for single-shot in-line self-interference incoherent holography

    Science.gov (United States)

    Weng, Jiawen; Clark, David C.; Kim, Myung K.

    2016-05-01

    A numerical reconstruction method based on compressive sensing (CS) for self-interference incoherent digital holography (SIDH) is proposed to achieve sectional imaging by single-shot in-line self-interference incoherent hologram. The sensing operator is built up based on the physical mechanism of SIDH according to CS theory, and a recovery algorithm is employed for image restoration. Numerical simulation and experimental studies employing LEDs as discrete point-sources and resolution targets as extended sources are performed to demonstrate the feasibility and validity of the method. The intensity distribution and the axial resolution along the propagation direction of SIDH by angular spectrum method (ASM) and by CS are discussed. The analysis result shows that compared to ASM the reconstruction by CS can improve the axial resolution of SIDH, and achieve sectional imaging. The proposed method may be useful to 3D analysis of dynamic systems.

  10. 3 ns single-shot read-out in a quantum dot-based memory structure

    International Nuclear Information System (INIS)

    Nowozin, T.; Bimberg, D.; Beckel, A.; Lorke, A.; Geller, M.

    2014-01-01

    Fast read-out of two to six charges per dot from the ground and first excited state in a quantum dot (QD)-based memory is demonstrated using a two-dimensional electron gas. Single-shot measurements on modulation-doped field-effect transistor structures with embedded InAs/GaAs QDs show read-out times as short as 3 ns. At low temperature (T = 4.2 K) this read-out time is still limited by the parasitics of the setup and the device structure. Faster read-out times and a larger read-out signal are expected for an improved setup and device structure

  11. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy.

    Science.gov (United States)

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-04-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10(13) photons/shot) hard X-rays. However, high energy resolution (Δhv/hv spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.

  12. Anti-spoof touchless 3D fingerprint recognition system using single shot fringe projection and biospeckle analysis

    Science.gov (United States)

    Chatterjee, Amit; Bhatia, Vimal; Prakash, Shashi

    2017-08-01

    Fingerprint is a unique, un-alterable and easily collected biometric of a human being. Although it is a 3D biological characteristic, traditional methods are designed to provide only a 2D image. This touch based mapping of 3D shape to 2D image losses information and leads to nonlinear distortions. Moreover, as only topographic details are captured, conventional systems are potentially vulnerable to spoofing materials (e.g. artificial fingers, dead fingers, false prints, etc.). In this work, we demonstrate an anti-spoof touchless 3D fingerprint detection system using a combination of single shot fringe projection and biospeckle analysis. For fingerprint detection using fringe projection, light from a low power LED source illuminates a finger through a sinusoidal grating. The fringe pattern modulated because of features on the fingertip is captured using a CCD camera. Fourier transform method based frequency filtering is used for the reconstruction of 3D fingerprint from the captured fringe pattern. In the next step, for spoof detection using biospeckle analysis a visuo-numeric algorithm based on modified structural function and non-normalized histogram is proposed. High activity biospeckle patterns are generated because of interaction of collimated laser light with internal fluid flow of the real finger sample. This activity reduces abruptly in case of layered fake prints, and is almost absent in dead or fake fingers. Furthermore, the proposed setup is fast, low-cost, involves non-mechanical scanning and is highly stable.

  13. Near field flow characteristics of the Bjork-Shiley Monostrut valve in a modified single shot valve chamber.

    Science.gov (United States)

    Manning, Keefe B; Przybysz, T Michael; Fontaine, Arnold A; Tarbell, John M; Deutsch, Steven

    2005-01-01

    In certain mechanical heart valves, cavitation has been shown to develop during closure and rebound, leading to valve damage, blood damage, and strokes. Whereas it is uncertain what causes mechanical heart valve related strokes, some evidence suggests that stable bubbles may be the culprits. Previous work has indicated that vortex cavitation may contribute to stable bubble growth. Therefore, in an effort to understand the vortex cavitation, laser Doppler velocimetry data are collected in a plane parallel to and 3 mm away from the major orifice during closure and rebound of a Bjork-Shiley Monostrut mechanical heart valve. A modified single shot chamber is used that incorporates a more realistic near valve geometry than those used in previous studies. The results show the formation of a vortex during closure, which intensifies during rebound and dissipates during the final closing cycle. A regurgitant jet with mean velocities up to 3 m/s through the clearance gap of the valve provides energy to the vortex. During the final closing cycle, the vortex breaks up into asymmetrical, small scale flow patterns. This study provides further evidence that stable bubble formation may stem from the intense vortex cavitation occurring during valve closure and rebound.

  14. Strong suppression of shot noise in a feedback-controlled single-electron transistor

    Science.gov (United States)

    Wagner, Timo; Strasberg, Philipp; Bayer, Johannes C.; Rugeramigabo, Eddy P.; Brandes, Tobias; Haug, Rolf J.

    2017-03-01

    Feedback control of quantum mechanical systems is rapidly attracting attention not only due to fundamental questions about quantum measurements, but also because of its novel applications in many fields in physics. Quantum control has been studied intensively in quantum optics but progress has recently been made in the control of solid-state qubits as well. In quantum transport only a few active and passive feedback experiments have been realized on the level of single electrons, although theoretical proposals exist. Here we demonstrate the suppression of shot noise in a single-electron transistor using an exclusively electronic closed-loop feedback to monitor and adjust the counting statistics. With increasing feedback response we observe a stronger suppression and faster freezing of charge current fluctuations. Our technique is analogous to the generation of squeezed light with in-loop photodetection as used in quantum optics. Sub-Poisson single-electron sources will pave the way for high-precision measurements in quantum transport similar to optical or optomechanical equivalents.

  15. Direct comparison of shot-to-shot noise performance of all normal dispersion and anomalous dispersion supercontinuum pumped with sub-picosecond pulse fiber-based laser

    Science.gov (United States)

    Klimczak, Mariusz; Soboń, Grzegorz; Kasztelanic, Rafał; Abramski, Krzysztof M.; Buczyński, Ryszard

    2016-01-01

    Coherence of supercontinuum sources is critical for applications involving characterization of ultrafast or rarely occurring phenomena. With the demonstrated spectral coverage of supercontinuum extending from near-infrared to over 10 μm in a single nonlinear fiber, there has been a clear push for the bandwidth rather than for attempting to optimize the dynamic properties of the generated spectrum. In this work we provide an experimental assessment of the shot-to-shot noise performance of supercontinuum generation in two types of soft glass photonic crystal fibers. Phase coherence and intensity fluctuations are compared for the cases of an anomalous dispersion-pumped fiber and an all-normal dispersion fiber. With the use of the dispersive Fourier transformation method, we demonstrate that a factor of 100 improvement in signal-to-noise ratio is achieved in the normal-dispersion over anomalous dispersion-pumped fiber for 390 fs long pump pulses. A double-clad design of the photonic lattice of the fiber is further postulated to enable a pump-related seeding mechanism of normal-dispersion supercontinuum broadening under sub-picosecond pumping, which is otherwise known for similar noise characteristics as modulation instability driven, soliton-based spectra. PMID:26759188

  16. A practical one-shot multispectral imaging system using a single image sensor.

    Science.gov (United States)

    Monno, Yusuke; Kikuchi, Sunao; Tanaka, Masayuki; Okutomi, Masatoshi

    2015-10-01

    Single-sensor imaging using the Bayer color filter array (CFA) and demosaicking is well established for current compact and low-cost color digital cameras. An extension from the CFA to a multispectral filter array (MSFA) enables us to acquire a multispectral image in one shot without increased size or cost. However, multispectral demosaicking for the MSFA has been a challenging problem because of very sparse sampling of each spectral band in the MSFA. In this paper, we propose a high-performance multispectral demosaicking algorithm, and at the same time, a novel MSFA pattern that is suitable for our proposed algorithm. Our key idea is the use of the guided filter to interpolate each spectral band. To generate an effective guide image, in our proposed MSFA pattern, we maintain the sampling density of the G -band as high as the Bayer CFA, and we array each spectral band so that an adaptive kernel can be estimated directly from raw MSFA data. Given these two advantages, we effectively generate the guide image from the most densely sampled G -band using the adaptive kernel. In the experiments, we demonstrate that our proposed algorithm with our proposed MSFA pattern outperforms existing algorithms and provides better color fidelity compared with a conventional color imaging system with the Bayer CFA. We also show some real applications using a multispectral camera prototype we built.

  17. Efficient Background Segmentation and Seed Point Generation for a Single-Shot Stereo System

    Science.gov (United States)

    Chen, Xiaobo; Xi, Juntong

    2017-01-01

    Single-shot stereo 3D shape measurement is becoming more popular due to its advantages of noise robustness and short acquisition period. One of the key problems is stereo matching, which is related to the efficiency of background segmentation and seed point generation, etc. In this paper, a more efficient and automated matching algorithm based on digital image correlation (DIC) is proposed. The standard deviation of image gradients and an adaptive threshold are employed to segment the background. Scale-invariant feature transform (SIFT)-based feature matching and two-dimensional triangulation are combined to estimate accurate initial parameters for seed point generation. The efficiency of background segmentation and seed point generation, as well as the measuring precision, are evaluated by experimental simulation and real tests. Experimental results show that the average segmentation time for an image with a resolution of 1280 × 960 pixels is 240 milliseconds. The efficiency of seed point generation is verified to be high with different convergence criteria. PMID:29194415

  18. Single shot three-dimensional pulse sequence for hyperpolarized13C MRI.

    Science.gov (United States)

    Wang, Jiazheng; Wright, Alan J; Hu, De-En; Hesketh, Richard; Brindle, Kevin M

    2017-02-01

    Metabolic imaging with hyperpolarized 13 C-labeled cell substrates is a promising technique for imaging tissue metabolism in vivo. However, the transient nature of the hyperpolarization, and its depletion following excitation, limits the imaging time and the number of excitation pulses that can be used. We describe here a single-shot three-dimensional (3D) imaging sequence and demonstrate its capability to generate 13 C MR images in tumor-bearing mice injected with hyperpolarized [1- 13 C]pyruvate. The pulse sequence acquires a stack-of-spirals at two spin echoes after a single excitation pulse and encodes the kz-dimension in an interleaved manner to enhance robustness to B 0 inhomogeneity. Spectral-spatial pulses are used to acquire dynamic 3D images from selected hyperpolarized 13 C-labeled metabolites. A nominal spatial/temporal resolution of 1.25 × 1.25 × 2.5 mm 3  × 2 s was achieved in tumor images of hyperpolarized [1- 13 C]pyruvate and [1- 13 C]lactate acquired in vivo. Higher resolution in the z-direction, with a different k-space trajectory, was demonstrated in measurements on a thermally polarized [1- 13 C]lactate phantom. The pulse sequence is capable of imaging hyperpolarized 13 C-labeled substrates at relatively high spatial and temporal resolutions and is robust to moderate system imperfections. Magn Reson Med 77:740-752, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  19. Angle-resolved spectral Fabry-Pérot interferometer for single-shot measurement of refractive index dispersion over a broadband spectrum

    Science.gov (United States)

    Dong, J. T.; Ji, F.; Xia, H. J.; Liu, Z. J.; Zhang, T. D.; Yang, L.

    2018-01-01

    An angle-resolved spectral Fabry-Pérot interferometer is reported for fast and accurate measurement of the refractive index dispersion of optical materials with parallel plate shape. The light sheet from the wavelength tunable laser is incident on the parallel plate with converging angles. The transmitted interference light for each angle is dispersed and captured by a 2D sensor, in which the rows and the columns are used to simultaneously record the intensities as a function of wavelength and incident angle, respectively. The interferogram, named angle-resolved spectral intensity distribution, is analyzed by fitting the phase information instead of finding the fringe peak locations that present periodic ambiguity. The refractive index dispersion and the physical thickness can be then retrieved from a single-shot interferogram within 18 s. Experimental results of an optical substrate standard indicate that the accuracy of the refractive index dispersion is less than 2.5  ×  10-5 and the relative uncertainty of the thickness is 6  ×  10-5 mm (3σ) due to the high stability and the single-shot measurement of the proposed system.

  20. One-shot deep-UV pulsed-laser-induced photomodification of hollow metal nanoparticles for high-density data storage on flexible substrates.

    Science.gov (United States)

    Wan, Dehui; Chen, Hsuen-Li; Tseng, Shao-Chin; Wang, Lon A; Chen, Yung-Pin

    2010-01-26

    In this paper, we report a new optical data storage method: photomodification of hollow gold nanoparticle (HGN) monolayers induced by one-shot deep-ultraviolet (DUV) KrF laser recording. As far as we are aware, this study is the first to apply HGNs in optical data storage and also the first to use a recording light source for the metal nanoparticles (NPs) that is not a surface plasmon resonance (SPR) wavelength. The short wavelength of the recording DUV laser improved the optical resolution dramatically. We prepared HGNs exhibiting two absorbance regions: an SPR peak in the near-infrared (NIR) region and an intrinsic material extinction in the DUV region. A single pulse from a KrF laser heated the HGNs and transformed them from hollow structures to smaller solid spheres. This change in morphology for the HGNs was accompanied by a significant blue shift of the SPR peak. Employing this approach, we demonstrated its patterning ability with a resolving power of a half-micrometer (using a phase mask) and developed a readout method (using a blue-ray laser microscope). Moreover, we prepared large-area, uniform patterns of monolayer HGNs on various substrates (glass slides, silicon wafers, flexible plates). If this spectral recording technique could be applied onto thin flexible tapes, the recorded data density would increase significantly relative to that of current rigid discs (e.g., compact discs).

  1. Pharmaceutical and immunological evaluation of a single-shot hepatitis B vaccine formulated with PLGA microspheres.

    Science.gov (United States)

    Shi, Li; Caulfield, Michael J; Chern, Rey T; Wilson, Roger A; Sanyal, Gautam; Volkin, David B

    2002-04-01

    A single-shot Hepatitis B vaccine formulation using poly(d,l)-lactide-co-glycolide acid (PLGA) microspheres as a delivery system was examined using a variety of biophysical and biochemical techniques as well as immunological evaluation in C3H mice. PLGA microsphere encapsulation of the Hepatitis B surface antigen (HBsAg), a lipoprotein particle, resulted in good recoveries of protein mass, protein particle conformational integrity, and in vitro antigenicity. Some partial delipidation of the HBsAg, however, was observed. The loading and encapsulation efficiency of HBsAg into the PLGA microspheres were measured along with the morphology and size distribution of the vaccine-loaded PLGA microspheres. The in vitro release kinetics of HBsAg from the PLGA microspheres was evaluated and found to be affected by experimental conditions such as stirring rate. HBsAg showed enhanced storage stability at 37 degrees C in the slightly acidic pH range reported to be found inside PLGA microspheres; thus, the antigen is relatively stable under conditions of temperature and pH that may mimic in vivo conditions. The immunogenicity of the microsphere formulations of HBsAg was compared with conventional aluminum adjuvant formulated HBsAg vaccine in C3H mice. Comparisons were made between aluminum formulations (one and two injections), PLGA microsphere formulations (single injection), and a mixture of aluminum and PLGA microsphere formulations (single injection). The nine-month serum antibody titers indicate that a single injection of a mixture of aluminum and PLGA-formulated HBsAg results in equal or better immune responses than two injections of aluminum-formulated HBsAg vaccine. Based on these in vitro and in vivo studies, it is concluded that HBsAg can be successfully encapsulated and recovered from the PLGA microspheres and a mixture of aluminum-adjuvanted and PLGA-formulated HBsAg can auto-boost an immune response in manner comparable to multiple injections of an aluminum

  2. Reference-free unwarping of single-shot spatiotemporally encoded MRI using asymmetric self-refocused echoes acquisition

    Science.gov (United States)

    Chen, Ying; Chen, Song; Zhong, Jianhui; Chen, Zhong

    2015-05-01

    This paper presents a phase evolution rewinding algorithm for correcting the geometric and intensity distortions in single-shot spatiotemporally encoded (SPEN) MRI with acquisition of asymmetric self-refocused echo trains. Using the field map calculated from the phase distribution of the source image, the off-resonance induced phase errors are successfully rewound through deconvolution. The alias-free partial Fourier transform reconstruction helps improve the signal-to-noise ratio of the field maps and the output images. The effectiveness of the proposed algorithm was validated through 7 T MRI experiments on a lemon, a water phantom, and in vivo rat head. SPEN imaging was evaluated using rapid acquisition by sequential excitation and refocusing (RASER) which produces uniform T2 weighting. The results indicate that the new technique can more robustly deal with the cases in which the images obtained with conventional single-shot spin-echo EPI are difficult to be restored due to serious field variations.

  3. The effect of shot noise on the start up of the fundamental and harmonics in free-electron lasers

    International Nuclear Information System (INIS)

    Freund, H. P.; Miner, W. H. Jr.; Giannessi, L.

    2008-01-01

    The problem of radiation start up in free-electron lasers (FELs) is important in the simulation of virtually all FEL configurations including oscillators and amplifiers in both seeded master oscillator power amplifier (MOPA) and self-amplified spontaneous emission (SASE) modes. Both oscillators and SASE FELs start up from spontaneous emission due to shot noise on the electron beam, which arises from the random fluctuations in the phase distribution of the electrons. The injected power in a MOPA is usually large enough to overwhelm the shot noise. However, this noise must be treated correctly in order to model the initial start up of the harmonics. In this paper, we discuss and compare two different shot noise models that are implemented in both one-dimensional wiggler-averaged (PERSEO) and non-wiggler-averaged (MEDUSA1D) simulation codes, and a three-dimensional non-wiggler-averaged (MEDUSA) formulation. These models are compared for examples describing both SASE and MOPA configurations in one dimension, in steady-state, and time-dependent simulations. Remarkable agreement is found between PERSEO and MEDUSA1D for the evolution of the fundamental and harmonics. In addition, three-dimensional correction factors have been included in the MEDUSA1D and PERSEO, which show reasonable agreement with MEDUSA for a sample MOPA in steady-state and time-dependent simulations

  4. Multishot versus single-shot pulse sequences in very high field fMRI: a comparison using retinotopic mapping.

    Directory of Open Access Journals (Sweden)

    Jascha D Swisher

    Full Text Available High-resolution functional MRI is a leading application for very high field (7 Tesla human MR imaging. Though higher field strengths promise improvements in signal-to-noise ratios (SNR and BOLD contrast relative to fMRI at 3 Tesla, these benefits may be partially offset by accompanying increases in geometric distortion and other off-resonance effects. Such effects may be especially pronounced with the single-shot EPI pulse sequences typically used for fMRI at standard field strengths. As an alternative, one might consider multishot pulse sequences, which may lead to somewhat lower temporal SNR than standard EPI, but which are also often substantially less susceptible to off-resonance effects. Here we consider retinotopic mapping of human visual cortex as a practical test case by which to compare examples of these sequence types for high-resolution fMRI at 7 Tesla. We performed polar angle retinotopic mapping at each of 3 isotropic resolutions (2.0, 1.7, and 1.1 mm using both accelerated single-shot 2D EPI and accelerated multishot 3D gradient-echo pulse sequences. We found that single-shot EPI indeed led to greater temporal SNR and contrast-to-noise ratios (CNR than the multishot sequences. However, additional distortion correction in postprocessing was required in order to fully realize these advantages, particularly at higher resolutions. The retinotopic maps produced by both sequence types were qualitatively comparable, and showed equivalent test/retest reliability. Thus, when surface-based analyses are planned, or in other circumstances where geometric distortion is of particular concern, multishot pulse sequences could provide a viable alternative to single-shot EPI.

  5. Single-shot readout of a superconducting flux qubit with a flux-driven Josephson parametric amplifier

    Science.gov (United States)

    Lin, Z. R.; Inomata, K.; Oliver, W. D.; Koshino, K.; Nakamura, Y.; Tsai, J. S.; Yamamoto, T.

    2013-09-01

    We report single-shot readout of a superconducting flux qubit by using a flux-driven Josephson parametric amplifier (JPA). After optimizing the readout power, gain of the JPA, and timing of the data acquisition, we observe the Rabi oscillations with a contrast of 74%, which is mainly limited by the bandwidth of the JPA and the energy relaxation of the qubit. The observation of quantum jumps between the qubit eigenstates under continuous monitoring indicates the nondestructiveness of the readout scheme.

  6. Clinical evaluation of single-shot and readout-segmented diffusion-weighted imaging in stroke patients at 3 T

    International Nuclear Information System (INIS)

    Morelli, John; Porter, David; Ai, Fei

    2013-01-01

    Background: Diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) is most commonly performed utilizing a single-shot echo-planar imaging technique (ss-EPI). Susceptibility artifact and image blur are severe when this sequence is utilized at 3 T. Purpose: To evaluate a readout-segmented approach to DWI MR in comparison with single-shot echo planar imaging for brain MRI. Material and Methods: Eleven healthy volunteers and 14 patients with acute and early subacute infarctions underwent DWI MR examinations at 1.5 and 3T with ss-EPI and readout-segmented echo-planar (rs-EPI) DWI at equal nominal spatial resolutions. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) calculations were made, and two blinded readers ranked the scans in terms of high signal intensity bulk susceptibility artifact, spatial distortions, image blur, overall preference, and motion artifact. Results: SNR and CNR were greatest with rs-EPI (8.1 ± 0.2 SNR vs. 6.0 ± 0.2; P -4 at 3T). Spatial distortions were greater with single-shot (0.23 ± 0.03 at 3T; P <0.001) than with rs-EPI (0.12 ± 0.02 at 3T). Combined with blur and artifact reduction, this resulted in a qualitative preference for the readout-segmented scans overall. Conclusion: Substantial image quality improvements are possible with readout-segmented vs. single-shot EPI - the current clinical standard for DWI - regardless of field strength (1.5 or 3 T). This results in improved image quality secondary to greater real spatial resolution and reduced artifacts from susceptibility in MR imaging of the brain

  7. Self-Calibrating Wave-Encoded Variable-Density Single-Shot Fast Spin Echo Imaging.

    Science.gov (United States)

    Chen, Feiyu; Taviani, Valentina; Tamir, Jonathan I; Cheng, Joseph Y; Zhang, Tao; Song, Qiong; Hargreaves, Brian A; Pauly, John M; Vasanawala, Shreyas S

    2018-04-01

    It is highly desirable in clinical abdominal MR scans to accelerate single-shot fast spin echo (SSFSE) imaging and reduce blurring due to T 2 decay and partial-Fourier acquisition. To develop and investigate the clinical feasibility of wave-encoded variable-density SSFSE imaging for improved image quality and scan time reduction. Prospective controlled clinical trial. With Institutional Review Board approval and informed consent, the proposed method was assessed on 20 consecutive adult patients (10 male, 10 female, range, 24-84 years). A wave-encoded variable-density SSFSE sequence was developed for clinical 3.0T abdominal scans to enable high acceleration (3.5×) with full-Fourier acquisitions by: 1) introducing wave encoding with self-refocusing gradient waveforms to improve acquisition efficiency; 2) developing self-calibrated estimation of wave-encoding point-spread function and coil sensitivity to improve motion robustness; and 3) incorporating a parallel imaging and compressed sensing reconstruction to reconstruct highly accelerated datasets. Image quality was compared pairwise with standard Cartesian acquisition independently and blindly by two radiologists on a scale from -2 to 2 for noise, contrast, confidence, sharpness, and artifacts. The average ratio of scan time between these two approaches was also compared. A Wilcoxon signed-rank tests with a P value under 0.05 considered statistically significant. Wave-encoded variable-density SSFSE significantly reduced the perceived noise level and improved the sharpness of the abdominal wall and the kidneys compared with standard acquisition (mean scores 0.8, 1.2, and 0.8, respectively, P variable-density sampling SSFSE achieves improved image quality with clinically relevant echo time and reduced scan time, thus providing a fast and robust approach for clinical SSFSE imaging. 1 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2018;47:954-966. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy

    International Nuclear Information System (INIS)

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Fujioka, Shinsuke; Azechi, Hiroshi; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori

    2016-01-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10 13 photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO 2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.

  9. Laser Peening Process and Its Impact on Materials Properties in Comparison with Shot Peening and Ultrasonic Impact Peening

    Science.gov (United States)

    Gujba, Abdullahi K.; Medraj, Mamoun

    2014-01-01

    The laser shock peening (LSP) process using a Q-switched pulsed laser beam for surface modification has been reviewed. The development of the LSP technique and its numerous advantages over the conventional shot peening (SP) such as better surface finish, higher depths of residual stress and uniform distribution of intensity were discussed. Similar comparison with ultrasonic impact peening (UIP)/ultrasonic shot peening (USP) was incorporated, when possible. The generation of shock waves, processing parameters, and characterization of LSP treated specimens were described. Special attention was given to the influence of LSP process parameters on residual stress profiles, material properties and structures. Based on the studies so far, more fundamental understanding is still needed when selecting optimized LSP processing parameters and substrate conditions. A summary of the parametric studies of LSP on different materials has been presented. Furthermore, enhancements in the surface micro and nanohardness, elastic modulus, tensile yield strength and refinement of microstructure which translates to increased fatigue life, fretting fatigue life, stress corrosion cracking (SCC) and corrosion resistance were addressed. However, research gaps related to the inconsistencies in the literature were identified. Current status, developments and challenges of the LSP technique were discussed. PMID:28788284

  10. Laser Peening Process and Its Impact on Materials Properties in Comparison with Shot Peening and Ultrasonic Impact Peening

    Directory of Open Access Journals (Sweden)

    Abdullahi K. Gujba

    2014-12-01

    Full Text Available The laser shock peening (LSP process using a Q-switched pulsed laser beam for surface modification has been reviewed. The development of the LSP technique and its numerous advantages over the conventional shot peening (SP such as better surface finish, higher depths of residual stress and uniform distribution of intensity were discussed. Similar comparison with ultrasonic impact peening (UIP/ultrasonic shot peening (USP was incorporated, when possible. The generation of shock waves, processing parameters, and characterization of LSP treated specimens were described. Special attention was given to the influence of LSP process parameters on residual stress profiles, material properties and structures. Based on the studies so far, more fundamental understanding is still needed when selecting optimized LSP processing parameters and substrate conditions. A summary of the parametric studies of LSP on different materials has been presented. Furthermore, enhancements in the surface micro and nanohardness, elastic modulus, tensile yield strength and refinement of microstructure which translates to increased fatigue life, fretting fatigue life, stress corrosion cracking (SCC and corrosion resistance were addressed. However, research gaps related to the inconsistencies in the literature were identified. Current status, developments and challenges of the LSP technique were discussed.

  11. Pin-hole array production and detailed data analysis for advanced single-shot X-ray imaging of laboratory plasmas

    Science.gov (United States)

    Levato, T.; Labate, L.; Pathak, N. C.; Cecchetti, C.; Koester, P.; Di Fabrizio, E.; Delogu, P.; Giulietti, A.; Giulietti, D.; Gizzi, L. A.

    2010-11-01

    Laser produced plasmas offer the unique opportunity to investigate physical mechanisms working at extremely high field in pulsed regime [1] (Gizzi et al., 2009). Future large scale infrastructure like HiPER and ELI may open new frontiers of knowledge in this way. Technologies needed for improving diagnostic in this field have a strong impact on a wide range of multi-disciplinary applications as for compact plasma-based accelerators [1,2] (Gizzi et al., 2009; Betti et al., 2009) laser fusion oriented experiments, three-dimensional microscopy and lithography. As an example the X-ray imaging, being a powerful diagnostic tool for deep investigation on different variety of laser produced plasma, has obtained a grooving effort in recent years. Large scale facilities working in single-pulse regime for laser fusion oriented experiments have evidenced the necessity to obtain spectrally resolved X-ray images of produced plasmas in a single shot. By combining the charge coupled devices (CCD) based single-photon detection technique with a pin-hole array (PHA) a new diagnostic technique was developed, as shown in recent experiments related to the European HiPER project [3] (Labate et al., 2009). Here we qualitatively describe the PHA production process on a heavy metal substrate by means of SEM images that show an internal diameter on the micrometer scale and an aspect ratio of about 20. The characterization of the X-ray contrast up to 90 keV is presented. The data analysis of the X-ray photons interaction on CCD, for spectrum reconstruction up to high energy, is described [4] (Levato et al., 2008).

  12. Pin-hole array production and detailed data analysis for advanced single-shot X-ray imaging of laboratory plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Levato, T., E-mail: tadzio.levato@lnf.infn.i [FLAME, Laboratori Nazionali di Frascati (LNF), Via E. Fermi 40, 00044 Frascati (Italy); Labate, L.; Pathak, N.C.; Cecchetti, C.; Koester, P. [ILIL, Consiglio Nazionale delle Ricerche (CNR), Pisa (Italy); Di Fabrizio, E. [BIONEM, Campus Magna Graecia University of Catanzaro (UMG) (Italy); Delogu, P. [University of Pisa, Department of Physics (Italy); Giulietti, A. [ILIL, Consiglio Nazionale delle Ricerche (CNR), Pisa (Italy); Giulietti, D. [University of Pisa, Department of Physics (Italy); Gizzi, L.A. [ILIL, Consiglio Nazionale delle Ricerche (CNR), Pisa (Italy)

    2010-11-11

    Laser produced plasmas offer the unique opportunity to investigate physical mechanisms working at extremely high field in pulsed regime (Gizzi et al., 2009). Future large scale infrastructure like HiPER and ELI may open new frontiers of knowledge in this way. Technologies needed for improving diagnostic in this field have a strong impact on a wide range of multi-disciplinary applications as for compact plasma-based accelerators (Gizzi et al., 2009; Betti et al., 2009) laser fusion oriented experiments, three-dimensional microscopy and lithography. As an example the X-ray imaging, being a powerful diagnostic tool for deep investigation on different variety of laser produced plasma, has obtained a grooving effort in recent years. Large scale facilities working in single-pulse regime for laser fusion oriented experiments have evidenced the necessity to obtain spectrally resolved X-ray images of produced plasmas in a single shot. By combining the charge coupled devices (CCD) based single-photon detection technique with a pin-hole array (PHA) a new diagnostic technique was developed, as shown in recent experiments related to the European HiPER project (Labate et al., 2009). Here we qualitatively describe the PHA production process on a heavy metal substrate by means of SEM images that show an internal diameter on the micrometer scale and an aspect ratio of about 20. The characterization of the X-ray contrast up to 90 keV is presented. The data analysis of the X-ray photons interaction on CCD, for spectrum reconstruction up to high energy, is described (Levato et al., 2008).

  13. Single-shot echo-planar MR sequences in the diagnosis of intracranial infectious diseases

    International Nuclear Information System (INIS)

    Tsuchiya, Kazuhiro; Katase, Shichiro; Yoshino, Ayako; Yamakami, Norio; Hachiya, Junichi

    1998-01-01

    The purpose of this study was to present our preliminary experience in the application of echo-planar-imaging (EPI) MR sequences for the diagnosis of intracranial infectious diseases and to assess the value of these sequences. We reviewed single-shot EPI MR images obtained at 1.5 T in 17 patients and compared these images with conventional or fast spin-echo (SE) or fluid attenuated inversion-recovery (FLAIR) images. The clinical diagnoses for the 17 patients were meningitis (2 patients), encephalitis or meningoencephalitis (7 patients), brain abscess (5 patients), epidural empyema (2 patients) and Creutzfeldt-Jakob disease (1 patient). We obtained EPI-T 2 -weighted (T 2 W) images in 8 patients, EPI-FLAIR images in 13 patients and EPI-diffusion-weighted (DW) images in 14 patients. Among the 8 patients for whom EPI-T 2 W imaging was performed, EPI-T 2 W imaging yielded superior results compared with SE-T 2 W imaging in 3 patients as a consequence of patient motion and equal results compared with SE-T 2 W imaging in 5 patients. Among the 13 patients for whom EPI-FLAIR imaging was performed, the EPI-FLAIR images were superior to conventional FLAIR images in 3 unstable patients. In the remaining 10 patients for whom EPI-FLAIR imaging was performed, EPI-FLAIR images were equivalent or inferior to conventional FLAIR images. In 6 patients with encephalitis or meningoencephalitis, the encephalitic lesions showed hyperintensity in EPI-DW images to a greater extent than in images obtained with the other techniques. In 3 patients, EPI-DW images also demonstrated hyperintensity for the contents of abscesses or areas of empyema that was not seen with the other imaging techniques. The value of EPI-T 2 W and EPI-FLAIR imaging is limited in uncooperative patients. EPI-DW imaging was found to be of value for the evaluation of several intracranial infectious diseases. (author)

  14. Single-shot echo-planar MR sequences in the diagnosis of intracranial infectious diseases

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Kazuhiro; Katase, Shichiro; Yoshino, Ayako; Yamakami, Norio; Hachiya, Junichi [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1998-06-01

    The purpose of this study was to present our preliminary experience in the application of echo-planar-imaging (EPI) MR sequences for the diagnosis of intracranial infectious diseases and to assess the value of these sequences. We reviewed single-shot EPI MR images obtained at 1.5 T in 17 patients and compared these images with conventional or fast spin-echo (SE) or fluid attenuated inversion-recovery (FLAIR) images. The clinical diagnoses for the 17 patients were meningitis (2 patients), encephalitis or meningoencephalitis (7 patients), brain abscess (5 patients), epidural empyema (2 patients) and Creutzfeldt-Jakob disease (1 patient). We obtained EPI-T{sub 2}-weighted (T{sub 2}W) images in 8 patients, EPI-FLAIR images in 13 patients and EPI-diffusion-weighted (DW) images in 14 patients. Among the 8 patients for whom EPI-T{sub 2}W imaging was performed, EPI-T{sub 2}W imaging yielded superior results compared with SE-T{sub 2}W imaging in 3 patients as a consequence of patient motion and equal results compared with SE-T{sub 2}W imaging in 5 patients. Among the 13 patients for whom EPI-FLAIR imaging was performed, the EPI-FLAIR images were superior to conventional FLAIR images in 3 unstable patients. In the remaining 10 patients for whom EPI-FLAIR imaging was performed, EPI-FLAIR images were equivalent or inferior to conventional FLAIR images. In 6 patients with encephalitis or meningoencephalitis, the encephalitic lesions showed hyperintensity in EPI-DW images to a greater extent than in images obtained with the other techniques. In 3 patients, EPI-DW images also demonstrated hyperintensity for the contents of abscesses or areas of empyema that was not seen with the other imaging techniques. The value of EPI-T{sub 2}W and EPI-FLAIR imaging is limited in uncooperative patients. EPI-DW imaging was found to be of value for the evaluation of several intracranial infectious diseases. (author)

  15. Sub-Shot-Noise Transmission Measurement Enabled by Active Feed-Forward of Heralded Single Photons

    Science.gov (United States)

    Sabines-Chesterking, J.; Whittaker, R.; Joshi, S. K.; Birchall, P. M.; Moreau, P. A.; McMillan, A.; Cable, H. V.; O'Brien, J. L.; Rarity, J. G.; Matthews, J. C. F.

    2017-07-01

    Harnessing the unique properties of quantum mechanics offers the possibility of delivering alternative technologies that can fundamentally outperform their classical counterparts. These technologies deliver advantages only when components operate with performance beyond specific thresholds. For optical quantum metrology, the biggest challenge that impacts on performance thresholds is optical loss. Here, we demonstrate how including an optical delay and an optical switch in a feed-forward configuration with a stable and efficient correlated photon-pair source reduces the detector efficiency required to enable quantum-enhanced sensing down to the detection level of single photons and without postselection. When the switch is active, we observe a factor of improvement in precision of 1.27 for transmission measurement on a per-input-photon basis compared to the performance of a laser emitting an ideal coherent state and measured with the same detection efficiency as our setup. When the switch is inoperative, we observe no quantum advantage.

  16. Modifications in morphological, structural, electrical and mechanical properties of Fe-1.0 wt.% Cu alloy on irradiation with 532 nm-6 ns Nd:YAG laser shots

    Science.gov (United States)

    Butt, M. Z.; Ur-Rehman, Khalil; Ali, Dilawar; Aftab, Muzamil; Usman Tanveer, M.

    2017-09-01

    The role of laser irradiation in tailoring the mechanical and electrical properties of Fe-1.0 wt.% Cu alloy has been explored, and compared with that of energetic particle irradiation. Mechanically polished/annealed Fe-1.0 wt.% Cu alloy specimens were irradiated in a vacuum ~10-3 Torr with 1-2500 laser shots. The laser fluence and laser intensity at the laser spot on the target surface were 86.54 J cm-2 and 14.4  ×  109 W cm-2, respectively. Different surface morphological features, e.g. dips, ripples, ridges, nanohillocks, microcones, micropillars, cavities, grooves, nano- and micro-size droplets, as well as tadpole-like structures, etc, were observed by SEM. Surface roughness was maximum for 1 laser shot, decreased by 40% for 250 laser shots, and then reduced by 70% in the range 500-2500. Crystallite size D and lattice strain ɛ were determined by Williamson-Hall analysis of x-ray diffractographs. An increasing linear relationship between electrical resistivity and Vickers hardness was found. In a plot of hardness versus D -1/2, crossover from Hall-Petch to Inverse Hall-Petch relation was observed at a critical value of D  ≈  11 nm. This behaviour was also followed by electrical resistivity. It is established that the nature of microstructural changes produced in the alloy on laser irradiation and on energetic particle irradiation is different.

  17. A second-order autocorrelator for single-shot measurement of ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    background intensity contrast ratio of 25 ps laser pulses from an active-passive mode-locked. Nd:YLF laser carried out in this mode are also presented. 2. Principle. The second order autocorrelation technique basically involves splitting a laser beam into two beams of equal intensity and overlapping them in a nonlinear ...

  18. A single-shot nonlinear autocorrelation approach for time-resolved physics in the vacuum ultraviolet spectral range

    International Nuclear Information System (INIS)

    Rompotis, Dimitrios

    2016-02-01

    In this work, a single-shot temporal metrology scheme operating in the vacuum-extreme ultraviolet spectral range has been designed and experimentally implemented. Utilizing an anti-collinear geometry, a second-order intensity autocorrelation measurement of a vacuum ultraviolet pulse can be performed by encoding temporal delay information on the beam propagation coordinate. An ion-imaging time-of-flight spectrometer, offering micrometer resolution has been set-up for this purpose. This instrument enables the detection of a magnified image of the spatial distribution of ions exclusively generated by direct two-photon absorption in the combined counter-propagating pulse focus and thus obtain the second-order intensity autocorrelation measurement on a single-shot basis. Additionally, an intense VUV light source based on high-harmonic generation has been experimentally realized. It delivers intense sub-20 fs Ti:Sa fifth-harmonic pulses utilizing a loose-focusing geometry in a long Ar gas cell. The VUV pulses centered at 161.8 nm reach pulse energies of 1.1 μJ per pulse, while the corresponding pulse duration is measured with a second-order, fringe-resolved autocorrelation scheme to be 18 ± 1 fs on average. Non-resonant, two-photon ionization of Kr and Xe and three-photon ionization of Ne verify the fifth-harmonic pulse intensity and indicate the feasibility of multi-photon VUV pump/VUV probe studies of ultrafast atomic and molecular dynamics. Finally, the extended functionally of the counter-propagating pulse metrology approach is demonstrated by a single-shot VUV pump/VUV probe experiment aiming at the investigation of ultrafast dissociation dynamics of O 2 excited in the Schumann-Runge continuum at 162 nm.

  19. Supplemental single shot femoral nerve block for total hip arthroplasty: impact on early postoperative care, pain management and lung function.

    Science.gov (United States)

    Wiesmann, T; Steinfeldt, T; Wagner, G; Wulf, H; Schmitt, J; Zoremba, M

    2014-01-01

    Peripheral regional anesthesia is beneficial in the management of postoperative pain in hip surgery, and can also reduce post-operative care unit (PACU) stay. Its opioid-sparing actions may also be beneficial for respiratory mechanics and pulmonary function. The aim of our pilot study was to evaluate the effect of a supplemental single shot femoral block for elective total hip arthroplasty on early respiratory function and postoperative management within the first 24 postoperative hours. We prospectively studied 80 patients undergoing total hip arthroplasty. Written informed consent was obtained after ethics committee approval. Forty patients were randomLy assigned to receive single shot femoral nerve block (FNB) using 15mL bupivacaine 0.25% and 20 mg clonidine while the remainder received standard treatment without nerve block (STN). Premedication and general anesthesia were standardized. Pulse oximetry saturation and spirometric lung function were measured preoperatively (baseline) and at 0.5 h, 2 h, 6 h and 24 h, after extubation breathing room air. PACU surveillance and postoperative pain therapy was standardized. Oxygen saturation and spirometry results were significantly better within the FNB group during the first six postoperative hours. Although VAS scores during the PACU stay did not significantly differ between the study groups, PACU discharge criteria were met earlier in the FNB group (116±40 min [mean±SD] vs. 152±47 min in the STN group). The FNB group exhibited significantly lower VAS scores at 6 and 24 hours. Supplemental single shot femoral nerve block for total hip arthroplasty resulted in earlier PACU discharge capability, improved lung function during the first six hours and better pain control within the first 24 postoperative hours.

  20. Single shot fringe pattern phase demodulation using Hilbert-Huang transform aided by the principal component analysis.

    Science.gov (United States)

    Trusiak, Maciej; Służewski, Łukasz; Patorski, Krzysztof

    2016-02-22

    Hybrid single shot algorithm for accurate phase demodulation of complex fringe patterns is proposed. It employs empirical mode decomposition based adaptive fringe pattern enhancement (i.e., denoising, background removal and amplitude normalization) and subsequent boosted phase demodulation using 2D Hilbert spiral transform aided by the Principal Component Analysis method for novel, correct and accurate local fringe direction map calculation. Robustness to fringe pattern significant noise, uneven background and amplitude modulation as well as local fringe period and shape variations is corroborated by numerical simulations and experiments. Proposed automatic, adaptive, fast and comprehensive fringe analysis solution compares favorably with other previously reported techniques.

  1. Simultaneous single-shot readout of multi-qubit circuits using a traveling-wave parametric amplifier

    Science.gov (United States)

    O'Brien, Kevin

    Observing and controlling the state of ever larger quantum systems is critical for advancing quantum computation. Utilizing a Josephson traveling wave parametric amplifier (JTWPA), we demonstrate simultaneous multiplexed single shot readout of 10 transmon qubits in a planar architecture. We employ digital image sideband rejection to eliminate noise at the image frequencies. We quantify crosstalk and infidelity due to simultaneous readout and control of multiple qubits. Based on current amplifier technology, this approach can scale to simultaneous readout of at least 20 qubits. This work was supported by the Army Research Office.

  2. Real time quantitative phase microscopy based on single-shot transport of intensity equation (ssTIE) method

    Science.gov (United States)

    Yu, Wei; Tian, Xiaolin; He, Xiaoliang; Song, Xiaojun; Xue, Liang; Liu, Cheng; Wang, Shouyu

    2016-08-01

    Microscopy based on transport of intensity equation provides quantitative phase distributions which opens another perspective for cellular observations. However, it requires multi-focal image capturing while mechanical and electrical scanning limits its real time capacity in sample detections. Here, in order to break through this restriction, real time quantitative phase microscopy based on single-shot transport of the intensity equation method is proposed. A programmed phase mask is designed to realize simultaneous multi-focal image recording without any scanning; thus, phase distributions can be quantitatively retrieved in real time. It is believed the proposed method can be potentially applied in various biological and medical applications, especially for live cell imaging.

  3. Development and Characterization of Two-Dimensional Gratings for Single-Shot X-ray Phase-Contrast Imaging

    Directory of Open Access Journals (Sweden)

    Margarita Zakharova

    2018-03-01

    Full Text Available Single-shot grating-based phase-contrast imaging techniques offer additional contrast modalities based on the refraction and scattering of X-rays in a robust and versatile configuration. The utilization of a single optical element is possible in such methods, allowing the shortening of the acquisition time and increasing flux efficiency. One of the ways to upgrade single-shot imaging techniques is to utilize customized optical components, such as two-dimensional (2D X-ray gratings. In this contribution, we present the achievements in the development of 2D gratings with UV lithography and gold electroplating. Absorption gratings represented by periodic free-standing gold pillars with lateral structure sizes from 5 µm to 25 µm and heights from 5 µm to 28 µm have shown a high degree of periodicity and defect-free patterns. Grating performance was tested in a radiographic setup using a self-developed quality assessment algorithm based on the intensity distribution histograms. The algorithm allows the final user to estimate the suitability of a specific grating to be used in a particular setup.

  4. LITGS: a new technique for single shot temperature and fuel concentration measurements in turbulent combusting environments

    Energy Technology Data Exchange (ETDEWEB)

    Fantoni, Roberta; Giorgi, M. [ENEA, Centro Ricerche Frascati, Frascati, RM (Italy). Dipt. Innovazione; De Risi, A.; Laforgia, D. [Lecce Univ., Lecce (Italy). Dipt. di Ingegneria dell' Innovazione

    1999-07-01

    In the present study the possibility to apply time resolved Laser Induced Thermal Grating Spectroscopy (LITGS) to detect fuel concentration and temperature in mixtures and flames at atmospheric pressure or higher is investigated. The resonant IR single photon absorption of two short pulse pump beams is used to initially generate a population grating, decaying into a thermal grating due to relaxation processes in the gas mixture. The thermal grating evolution is followed by monitoring the scattered signal of a cw visible probe beam after the end of the pump pulse. The use of the IR optical transition of diesel fuel assured a high species selectivity and a negligible influence of the visible emission background due to the presence of electronically excited species in flames. Fuel concentration and temperature measurements in a pressurized cell, with pressure ranging between 0.1 an 1.5 MPa, and in a diffusion turbulent flame generated by a burner feed with diesel fuel operating at atmospheric pressure are presented. The experimental investigation shows that LITGS signal increase linearly with gas density. This characteristic makes LITGS a very interesting technique for fuel distribution and temperature measurements in hostile (high-pressure and turbulent flow) environments. Detection limit for diesel fuel at atmospheric pressure is found to be about 40 ppm and it decreases with the increase of the pressure. The low detection limit which can be reached makes this technique suitable also for monitoring minor species and radicals. [Italian] Nel presente studio si investiga la possibilita' di applicare la tecnica LITGS (Laser Induced Thermal Grating Spectroscopy) per misurare la concentrazione e la temperatura di carburante in miscele e fiamme a pressiona atmosferica o superiore. L'assorbimento risonante di un singolo fotone IR proveniente da uno dei due laser impulsati di pompa e' utilizzato per generare inizialmente un reticolo di popolazione, che decade

  5. Laser Transmitter for the Lunar Orbit Laser Altimeter (LOLA) Instrument

    Science.gov (United States)

    Yu, Anthony W.; Novo-Gradac, Anne-Marie; Shaw, George B.; Li, Steven X.; Krebs, Danny C.; Ramos-Izquierdo, Luis A.; Unger, Glenn; Lukemire, Alan

    2008-01-01

    We present the final configuration of the space flight laser transmitter as delivered to the LOLA instrument. The laser consists of two oscillators on a single bench, each capable of providing one billion plus shots.

  6. The lunar orbiter laser altimeter (LOLA) laser transmitter

    Science.gov (United States)

    Yu, Anthony W.; Novo-Gradac, Anne Marie; Shaw, George B.; Unger, Glenn; Ramos-Izquierdo, Luis A.; Lukemire, Alan

    2008-02-01

    We present the final configuration of the space flight laser transmitter as delivered to the LOLA instrument. The laser consists of two oscillators with co-aligned outputs on a single bench, each capable of providing one billion plus shots.

  7. Compact laser radar based on a subnanosecond laser diode transmitter and a two-dimensional CMOS single-photon receiver

    Science.gov (United States)

    Huikari, Jaakko; Jahromi, Sahba; Jansson, Jussi-Pekka; Kostamovaara, Juha

    2018-02-01

    A pulsed TOF laser radar utilizing the single-photon detection mode has been implemented, and its performance is characterized. The transmitter employs a QW double-heterostructure laser diode producing 0.6 nJ/100 ps laser pulses at a central wavelength of ˜810 nm. The detector is a single-chip IC manufactured in the standard 0.35-μm HV CMOS process, including a 9×9 single-photon avalanche diode (SPAD) array and a 10-channel time-to-digital converter (TDC) circuit. Both the SPAD array and the TDC circuit support a time gating feature allowing photon detection to occur only within a predefined time window. The SPAD array also supports a 3×3 SPADs subarray selection feature to respond to the laser spot wandering effect due to the paraxial optics and to reduce background radiation-induced detections. The characterization results demonstrate a distance measurement accuracy of +/-0.5 mm to a target at 34 m having 11% reflectivity. The signal detection rate is 28% at a laser pulsing rate of 100 kHz. The single-shot precision of the laser radar is ˜20 mm (FWHM). The deteriorating impact of high-level background radiation conditions on the SNR is demonstrated, as also is a scheme to improve this by means of detector time gating.

  8. Generating multiple contrasts using single-shot radial T1 sensitive and insensitive steady-state imaging.

    Science.gov (United States)

    Benkert, Thomas; Bartsch, Andreas J; Blaimer, Martin; Jakob, Peter M; Breuer, Felix A

    2015-06-01

    Recently, the (Resolution Enhanced-) T1 insensitive steady-state imaging (TOSSI) approach has been proposed for the fast acquisition of T2 -weighted images. This has been achieved by balanced steady-state free precession (bSSFP) imaging between unequally spaced inversion pulses. The purpose of this work is to present an extension of this technique, considerably increasing both the efficiency and possibilities of TOSSI. A radial trajectory in combination with an appropriate view-sharing reconstruction is used. Because each projection traverses the contrast defining k-space center, several different contrasts can be extracted from a single-shot measurement. These contrasts include various T2 -weightings and T2 /T1 -weighting if an even number of inversion pulses is used, while an odd number allow the generation of several images with predefined tissue types cancelled. The approach is validated for brain and abdominal imaging at 3.0 Tesla. Results are compared with RE-TOSSI, bSSFP, and turbo spin-echo images and are shown to provide similar contrasts in a fraction of scan time. Furthermore, the potential utility of the approach is illustrated by images obtained from a brain tumor patient. Radial T1 sensitive and insensitive steady-state imaging is able to generate multiple contrasts out of one single-shot measurement in a short scan time. © 2014 Wiley Periodicals, Inc.

  9. Single shot damage mechanism of Mo/Si multilayer optics under intense pulsed XUV-exposure

    Czech Academy of Sciences Publication Activity Database

    Khorsand, A.R.; Sobierajski, R.; Louis, E.; Bruijn, S.; van Hattum, E.D.; van de Kruijs, R.W.E.; Jurek, M.; Klinger, D.; Pelka, J. B.; Juha, Libor; Burian, Tomáš; Chalupský, Jaromír; Cihelka, Jaroslav; Hájková, Věra; Vyšín, Luděk; Jastrow, U.; Stojanovic, N.; Toleikis, S.; Wabnitz, H.; Tiedtke, K.; Sokolowski-Tinten, K.; Shymanovich, U.; Krzywinski, J.; Hau-Riege, S.; London, R.; Gleeson, A.; Gullikson, E.M.; Bijkerk, F.

    2010-01-01

    Roč. 18, č. 2 (2010), 700-712 ISSN 1094-4087 R&D Projects: GA AV ČR KAN300100702; GA MŠk LC510; GA MŠk(CZ) LC528; GA MŠk LA08024; GA AV ČR IAA400100701 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser damage * thermal effects * multilayers * optical design and fabrication * free-electron lasers Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.749, year: 2010

  10. Shot-noise-limited laser power stabilization with a high-power photodiode array.

    Science.gov (United States)

    Kwee, Patrick; Willke, Benno; Danzmann, Karsten

    2009-10-01

    The output power of a cw Nd:YAG laser was stabilized in a dc-coupled feedback loop with a low-noise multiphotodiode detector and an electro-optic amplitude modulator in the frequency band from 1 Hz to 1 kHz. For the first time, to our knowledge, an independently measured relative power noise of 2.4 x 10(-9) Hz(-1/2) at 10 Hz was achieved, fulfilling the power stability requirements of the Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) gravitational wave detector.

  11. Single-shot EPI with Nyquist ghost compensation: Interleaved Dual-Echo with Acceleration (IDEA) EPI

    Science.gov (United States)

    Poser, Benedikt A; Barth, Markus; Goa, Pål-Erik; Deng, Weiran; Stenger, V Andrew

    2012-01-01

    Echo planar imaging is most commonly used for BOLD fMRI, owing to its sensitivity and acquisition speed. A major problem with EPI is Nyquist (N/2) ghosting, most notably at high field. EPI data are acquired under an oscillating readout gradient and hence vulnerable to gradient imperfections such as eddy current delays and off-resonance effects, as these cause inconsistencies between odd and even k-space lines after time reversal. We propose a straightforward and pragmatic method herein termed Interleaved Dual Echo with Acceleration (IDEA) EPI: Two k-spaces (echoes) are acquired under the positive and negative readout lobes, respectively, by performing phase blips only before alternate readout gradients. From these two k-spaces, two almost entirely ghost free images per shot can be constructed, without need for phase correction. The doubled echo train length can be compensated by parallel imaging and/or partial Fourier acquisition. The two k-spaces can either be complex-averaged during reconstruction, which results in near-perfect cancellation of residual phase errors, or reconstructed into separate images. We demonstrate the efficacy of IDEA EPI and show phantom and in vivo images at both 3 and 7 Tesla. PMID:22411762

  12. Blood Bupivacaine Concentrations After a Combined Single-Shot Sciatic Block and a Continuous Femoral Nerve Block in Pediatric Patients: A Prospective Observational Study.

    Science.gov (United States)

    Suresh, Santhanam; De Oliveira, Gildasio S

    2017-05-01

    We evaluated blood bupivacaine concentrations in children having a single-shot sciatic and continuous femoral blocks after anterior cruciate ligament repair. Dried blood spot samples were analyzed for bupivacaine levels at 0, 5, 15, 30, 60, and 120 minutes and 4, 24, and 48 hours. The highest 99% upper confidence interval limit was 135 ng/mL at the 4-hour evaluation point. The 99% upper confidence interval was below potentially toxic levels (1500 ng/mL) across all sampling times. The risk of local anesthetic toxicity in pediatric patients receiving single-shot sciatic and continuous femoral nerve blocks is very low.

  13. Diffusion-weighted single shot echo planar imaging of colorectal cancer using a sensitivity-encoding technique

    International Nuclear Information System (INIS)

    Nasu, Katsuhiro; Kuroki, Yoshihumi; Murakami, Koji; Nawano, Shigeru; Kuroki, Seiko; Moriyama, Noriyuki

    2004-01-01

    We wanted to determine the feasibility of diffusion-weighted single shot echo planar imaging using a sensitivity encoding diffusion weighted imaging (SENSE-DWI) technique in depicting colorectal cancer. Forty-two patients with sigmoid colon cancer and rectal cancer, all proven pathologically, were examined on T2-turbo spin echo (TSE) and SENSE-DWI. No bowel preparation was performed before examination. The b-factors used in SENSE-DWI were zero and 1000 s/mm 2 . In 10 randomly selected cases, the images whose b-factors were 250 and 500 s/mm 2 were also obtained. The reduction factor of SENSE was 2.0 in all sequences. Two radiologists evaluated the obtained images from the viewpoints of tumor detectability, image distortion and misregistration of the tumors. The apparent diffusion coefficients (ADCs) of the tumors and urine in the urinary bladders in each patient were measured to evaluate the correlation between ADC and pathological classification of each tumor. All tumors were depicted hyperintensely on SENSE-DWI. Even though single shot echo planar imaging (EPI) was used, the image distortion and misregistration was quite pronounced because of simultaneous use of SENSE. On SENSE-DWI whose b-factor was 1000 s/mm 2 , the normal colon wall and feces were always hypointense and easily differentiated from the tumors. The mean ADC value of each tumor was 1.02±0.1 (x 10 -3 ) mm 2 /s. No overt correlation can be pointed out between ADC and pathological classification of each tumor. SENSE-DWI is a feasible method for depicting colorectal cancer. SENSE-DWI provides strong contrast among colorectal cancers, normal rectal wall and feces. (authors)

  14. Clinical application of Half Fourier Acquisition Single Shot Turbo Spin Echo (HASTE) imaging accelerated by simultaneous multi-slice acquisition.

    Science.gov (United States)

    Schulz, Jenni; P Marques, José; Ter Telgte, Annemieke; van Dorst, Anouk; de Leeuw, Frank-Erik; Meijer, Frederick J A; Norris, David G

    2018-01-01

    As a single-shot sequence with a long train of refocusing pulses, Half-Fourier Acquisition Single-Shot Turbo-Spin-Echo (HASTE) suffers from high power deposition limiting use at high resolutions and high field strengths, particularly if combined with acceleration techniques such as simultaneous multi-slice (SMS) imaging. Using a combination of multiband (MB)-excitation and PINS-refocusing pulses will effectively accelerate the acquisition time while staying within the SAR limitations. In particular, uncooperative and young patients will profit from the speed of the MB-PINS HASTE sequence, as clinical diagnosis can be possible without sedation. Materials and MethodsMB-excitation and PINS-refocusing pulses were incorporated into a HASTE-sequence with blipped CAIPIRINHA and TRAPS including an internal FLASH reference scan for online reconstruction. Whole brain MB-PINS HASTE data were acquired on a Siemens 3T-Prisma system from 10 individuals and compared to a clinical HASTE protocol. ResultsThe proposed MB-PINS HASTE protocol accelerates the acquisition by about a factor 2 compared to the clinical HASTE. The diagnostic image quality proved to be comparable for both sequences for the evaluation of the overall aspect of the brain, the detection of white matter changes and areas of tissue loss, and for the evaluation of the CSF spaces although artifacts were more frequently encountered with MB-PINS HASTE. ConclusionsMB-PINS HASTE enables acquisition of slice accelerated highly T2-weighted images and provides good diagnostic image quality while reducing acquisition time. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Single-mode biological distributed feedback laser

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Maier-Flaig, Florian; Lemmer, Uli

    2013-01-01

    Single-mode second order distributed feedback (DFB) lasers of riboflavin (vitamin B2) doped gelatine films on nanostructured low refractive index material are demonstrated. Manufacturing is based on a simple UV nanoimprint and spin-coating. Emission wavelengths of 543 nm and 562 nm for two...

  16. 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.

  17. Diffusion-weighted imaging of the sellar region: A comparison study of BLADE and single-shot echo planar imaging sequences

    Energy Technology Data Exchange (ETDEWEB)

    Yiping, Lu [Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Rd. Middle, Shanghai 200040 (China); Hui, Liu [MR Collaboration NE Asia, Siemens Healthcare, Siemens Ltd., China, Shanghai 201318 (China); Kun, Zhou [MR PLM APPL, Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen 518057 (China); Daoying, Geng, E-mail: GengdaoyingGDY@163.com [Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Rd. Middle, Shanghai 200040 (China); Bo, Yin, E-mail: yinbo7@163.com [Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Rd. Middle, Shanghai 200040 (China)

    2014-07-15

    Purpose: The purpose of this study is to compare BLADE diffusion-weighted imaging (DWI) with single-shot echo planar imaging (EPI) DWI on the aspects of feasibility of imaging the sellar region and image quality. Methods: A total of 3 healthy volunteers and 52 patients with suspected lesions in the sellar region were included in this prospective intra-individual study. All exams were performed at 3.0 T with a BLADE DWI sequence and a standard single-shot EP-DWI sequence. Phantom measurements were performed to measure the objective signal-to-noise ratio (SNR). Two radiologists rated the image quality according to the visualisation of the internal carotid arteries, optic chiasm, pituitary stalk, pituitary gland and lesion, and the overall image quality. One radiologist measured lesion sizes for detecting their relationship with the image score. Results: The SNR in BLADE DWI sequence showed no significant difference from the single-shot EPI sequence (P > 0.05). All of the assessed regions received higher scores in BLADE DWI images than single-shot EP-DWI.

  18. Flexible Low-power SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout

    Science.gov (United States)

    England, Troy; Lilly, Michael; Curry, Matthew; Carr, Stephen; Carroll, Malcolm

    Fast, low-power quantum state readout is one of many challenges facing quantum information processing. Single electron transistors (SETs) are potentially fast, sensitive detectors for performing spin readout of electrons bound to Si:P donors. From a circuit perspective, however, their output impedance and nonlinear conductance are ill suited to drive the parasitic capacitance of coaxial conductors used in cryogenic environments, necessitating a cryogenic amplification stage. We will introduce two new amplifier topologies that provide excellent gain versus power tradeoffs using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). The AC HBT allows in-situ adjustment of power dissipation during an experiment and can provide gain in the millikelvin temperature regime while dissipating less than 500 nW. The AC Current Amplifier maximizes gain at nearly 800 A/A. We will also show results of using these amplifiers with SETs at 4 K. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000. Flexible Low-power SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout.

  19. Poloxamer 407-chitosan grafted thermoresponsive hydrogels achieve synchronous and sustained release of antigen and adjuvant from single-shot vaccines.

    Science.gov (United States)

    Bobbala, Sharan; Gibson, Blake; Gamble, Allan B; McDowell, Arlene; Hook, Sarah

    2018-03-02

    Sustained release vaccine delivery systems may enhance the immunogenicity of subunit vaccines and reduce the need for multiple vaccinations. The aim of this study was to develop a thermoresponsive hydrogel using poloxamer 407-chitosan (CP) grafted copolymer as a delivery system for single-shot sustained release vaccines. The CP copolymer was synthesized using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemistry. The CP copolymer was a free flowing solution at ambient temperature and transformed rapidly into a gel at body temperature. The hydrogels were loaded with vaccine antigen and adjuvants or the vaccine components were encapsulated in poly (lactic-co-glycolic acid) nanoparticles (PLGA-NP) in order to ensure synchronous release. The CP hydrogels were stable for up to 18 days in vitro. Release of both nanoparticles and the individual components was complete, with release of the individual components being modulated by incorporation into nanoparticles. In vivo, a single dose of CP hydrogel vaccine induced strong, long lasting, cellular and humoral responses that could protect against the development of tumors in a murine melanoma model. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. The value of single-shot black-blood MR imaging for mapping of the coronary arteries: a comparison of four different orientations during breath-holding and free breathing.

    NARCIS (Netherlands)

    Holland, A.E.; Engelbrecht, M.R.W.; Barentsz, J.O.; Heijstraten, F.M.J.; Goldfarb, J.W.

    2002-01-01

    The value of ECG-gated single-shot black-blood MR imaging for rapid visualization of the origin and course of the coronary arteries was investigated. The study population included 28 patients with known or suspected cardiac disease. ECG-gated single-shot black-blood MR acquisitions were acquired in

  1. Single-shot X-ray phase-contrast imaging using two-dimensional gratings

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Genta; Itoh, Hidenosuke; Nagai, Kentaro; Nakamura, Takashi; Yamaguchi, Kimiaki; Kondoh, Takeshi; Handa, Soichiro; Ouchi, Chidane; Teshima, Takayuki; Setomoto, Yutaka; Den, Toru [Frontier Research Center, Corporate R and D Headquarters, Canon Inc., 3-30-2 Shimomaruko, Ohta-ku, Tokyo 146-8501 (Japan); Optics Technology Development Center, Corporate R and D Headquarters, Canon Inc., 23-10, Kiyohara-Kogyodanchi, Utsunomiya Tochigi 321-3231 (Japan); Nanotechnology R and D Center, Corporate R and D Headquarters, Canon Inc., 3-30-2 Shimomaruko, Ohta-ku, Tokyo 146-8501 (Japan)

    2012-07-31

    We developed a two-dimensional gratings-based X-ray interferometer that requires only a single exposure for clinical radiography. The interferometer consisted of a checkerboard phase grating for {pi} phase modulation and a latticed amplitude grating. Using a synchrotron radiation source, the phase grating modulates the X-rays and generates a self-image, transformed to a moire fringe by the amplitude grating. To allow use of a conventional X-ray tube, the latticed source grating was installed downstream from the X-ray tube. Differential phase-contrast and scattering images in two orthogonal directions were obtained by Fourier analysis of the single moire fringe image and an absorption image. Results show that characteristic features of soft tissue in two orthogonal directions were clearly shown in the differential phase-contrast images.

  2. Ankle Block vs Single-Shot Popliteal Fossa Block as Primary Anesthesia for Forefoot Operative Procedures: Prospective, Randomized Comparison.

    Science.gov (United States)

    Schipper, Oliver N; Hunt, Kenneth J; Anderson, Robert B; Davis, W Hodges; Jones, Carroll P; Cohen, Bruce E

    2017-11-01

    Postoperative pain is often difficult to control with oral medications, requiring large doses of opioid analgesia. Regional anesthesia may be used for primary anesthesia, reducing the need for general anesthetic and postoperative pain medication requirements in the immediate postoperative period. The purpose of this study was to compare the analgesic effects of an ankle block (AB) to a single-shot popliteal fossa block (PFB) for patients undergoing orthopedic forefoot procedures. All patients having elective outpatient orthopedic forefoot procedures were invited to participate in the study. Patients were prospectively randomized to receive either an ultrasound-guided AB or PFB by a board-certified anesthesiologist prior to their procedure. Intraoperative conversion to general anesthesia and postanesthesia care unit (PACU) opioid requirements were recorded. Postoperative pain was assessed using the visual analog scale (VAS) at regular time intervals until 8 am on postoperative day (POD) 2. Patients rated the effectiveness of the block on a 1 to 5 scale, with 5 being very effective. A total of 167 patients participated in the study with 88 patients (53%) receiving an AB and 79 (47%) receiving a single-shot PFB. There was no significant difference in the rate of conversion to general anesthesia between the 2 groups (13.6% [12/88] AB vs 12.7% [10/79] PFB). PACU morphine requirements and doses were significantly reduced in the PFB group ( P = .004) when compared to the AB group. The VAS was also significantly lower for the PFB patients at 10 pm on POD 0 (4.6 vs 1.6, P PFB 10.1%, P = .51) and there were no significant differences in residual sensory paresthesias (AB 2.3% [2/88] vs PFB 5.1% [4/79], P = .29), motor loss (0% vs 0%), or block site pain and/or erythema (AB 6.9% [6/88] vs PFB 5.1% [4/79], P = .44). The analgesic effect of the PFB lasted significantly longer when compared to the ankle block (AB 14.5 hours vs PFB 20.9 hours, P PFB 4.82/5, P = .68). Regional

  3. Development of single shot 1D-Raman scattering measurements for flames

    Science.gov (United States)

    Biase, Amelia; Uddi, Mruthunjaya

    2017-11-01

    The majority of energy consumption in the US comes from burning fossil fuels which increases the concentration of carbon dioxide in the atmosphere. The increasing concentration of carbon dioxide in the atmosphere has negative impacts on the environment. One solution to this problem is to study the oxy-combustion process. A pure oxygen stream is used instead of air for combustion. Products contain only carbon dioxide and water. It is easy to separate water from carbon dioxide by condensation and the carbon dioxide can be captured easily. Lower gas volume allows for easier removal of pollutants from the flue gas. The design of a system that studies the oxy-combustion process using advanced laser diagnostic techniques and Raman scattering measurements is presented. The experiments focus on spontaneous Raman scattering. This is one of the few techniques that can provide quantitative measurements of the concentration and temperature of different chemical species in a turbulent flow. The experimental design and process of validating the design to ensure the data is accurate is described. The Raman data collected form an experimental data base that is used for the validation of spontaneous Raman scattering in high pressure environments for the oxy-combustion process. NSF EEC 1659710.

  4. Comparing SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout

    Science.gov (United States)

    England, Troy; Curry, Matthew; Carr, Stephen; Mounce, Andrew; Jock, Ryan; Sharma, Peter; Bureau-Oxton, Chloe; Rudolph, Martin; Hardin, Terry; Carroll, Malcolm

    Fast, low-power quantum state readout is one of many challenges facing quantum information processing. Single electron transistors (SETs) are potentially fast, sensitive detectors for performing spin readout. From a circuit perspective, however, their output impedance and nonlinear conductance are ill suited to drive the parasitic capacitance of coaxial conductors used in cryogenic environments, necessitating a cryogenic amplification stage. We will compare two amplifiers based on single-transistor circuits implemented with silicon germanium heterojunction bipolar transistors. Both amplifiers provide gain at low power levels, but the dynamics of each circuit vary significantly. We will explore the gain mechanisms, linearity, and noise of each circuit and explain the situations in which each amplifier is best used. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  5. Magnetic resonance urography in pediatrics: utilization of ultrafast single-shot spin echo sequences; Urografia por resonancia magnetic en pediatria: utilizacion de las secuencias ultrarrapidas single shot en eco del espin

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C.; Martin, J.; Duran, C. [Unidad de Diagnostico por la Imagen de Alta Tecnologia (UDIAT). Sabadell (Spain); Rigol, S.; Rojo, J. C. [Corporacion Sanatiaria Parc Tauli. Sabadell (Spain)

    1999-07-01

    To determine the value of magnetic resonance urography (MRU) using ultrafast single-shot (SS) rapid acquisition with relaxation enhancement (RARE) and half-Fourier (HF) SS-RARE (SS-HF-RARE or HASTE) in the evaluation of congenital urinary tract anomalies in pediatric patients, and their possible application as alternatives to intravenous urography (IVU). Eighteen children (11 boys and 7 girls) aged 2 months to 15 years (mean: 5 years) with a total of 19 congenital urinary tract anomalies were studies by MU using SS-RARE and HASTE sequences in a 1 Tesla scanner. All the patients had previously been studies by ultrasound (US) and IVU. Twelve patients required anesthesia. The images were acquired by means of a HASTE sequence with multisection technique (TR, infinite; TE{sub e}f, 87 msec; echo train, 128; interval between echoes, 10.9 msec; total acquisition time, 13 sections/12 seconds), and SS-RARE (TR, infinite; TE{sub e}f, 1.100 msec; echo train, 240, and acquisition time, 7 seconds). Four radiologists evaluated the images independently; two who reviewed the IV images in consensus and two who reviewed the MRU images in consensus. The images were evaluated to assess the dilatation of the urinary tract and their utility in detecting the level and cause of the obstruction. MRU images revealed the urinary tract dilation, the level of the obstruction and the type of anomaly in 18 patients (100%), while IVU provided this information in only 10 [ sensitivity, 53%, 95% confidence interval (29%, 76%)]. The mean time required for MRU was 20 minutes (range: 7 to 30 minutes), while that of IVU was 1,242 minutes (range: 45 to 1,440 minutes). MRU using ultrafast single-short spin echo sequences is a rapid and effective technique that permits and excellent evaluation of congenital urinary tract anomalies in pediatric patients and does not require the administration of contrast media or ionizing radiation. (Author) 10 refs.

  6. Simple and Reproducible Sample Preparation for Single-Shot Phosphoproteomics with High Sensitivity

    DEFF Research Database (Denmark)

    Jersie-Christensen, Rosa R.; Sultan, Abida; Olsen, Jesper V

    2016-01-01

    The traditional sample preparation workflow for mass spectrometry (MS)-based phosphoproteomics is time consuming and usually requires multiple steps, e.g., lysis, protein precipitation, reduction, alkylation, digestion, fractionation, and phosphopeptide enrichment. Each step can introduce chemical...... artifacts, in vitro protein and peptide modifications, and contaminations. Those often result in sample loss and affect the sensitivity, dynamic range and accuracy of the mass spectrometric analysis. Here we describe a simple and reproducible phosphoproteomics protocol, where lysis, denaturation, reduction......, and alkylation are performed in a single step, thus reducing sample loss and increasing reproducibility. Moreover, unlike standard cell lysis procedures the cell harvesting is performed at high temperatures (99 °C) and without detergents and subsequent need for protein precipitation. Phosphopeptides are enriched...

  7. Single shot of 17D vaccine may not confer life-long protection against yellow fever.

    Science.gov (United States)

    Vasconcelos, Pedro Fc

    2018-02-01

    The yellow fever (YF) vaccine has been used since the 1930s to prevent YF, which is a severe infectious disease caused by the yellow fever virus (YFV), and mainly transmitted by Culicidae mosquitoes from the genera Aedes and Haemagogus . Until 2013, the World Health Organization (WHO) recommended the administration of a vaccine dose every ten years. A new recommendation of a single vaccine dose to confer life-long protection against YFV infection has since been established. Recent evidence published elsewhere suggests that at least a second dose is needed to fully protect against YF disease. Here, we discuss the feasibility of administering multiple doses, the necessity for a new and modern vaccine, and recommend that the WHO conveys a meeting to discuss YFV vaccination strategies for people living in or travelling to endemic areas.

  8. Spectrally resolved single-shot wavefront sensing of broadband high-harmonic sources

    Science.gov (United States)

    Freisem, L.; Jansen, G. S. M.; Rudolf, D.; Eikema, K. S. E.; Witte, S.

    2018-03-01

    Wavefront sensors are an important tool to characterize coherent beams of extreme ultraviolet radiation. However, conventional Hartmann-type sensors do not allow for independent wavefront characterization of different spectral components that may be present in a beam, which limits their applicability for intrinsically broadband high-harmonic generation (HHG) sources. Here we introduce a wavefront sensor that measures the wavefronts of all the harmonics in a HHG beam in a single camera exposure. By replacing the mask apertures with transmission gratings at different orientations, we simultaneously detect harmonic wavefronts and spectra, and obtain sensitivity to spatiotemporal structure such as pulse front tilt as well. We demonstrate the capabilities of the sensor through a parallel measurement of the wavefronts of 9 harmonics in a wavelength range between 25 and 49 nm, with up to lambda/32 precision.

  9. Observation of single artificial atom optical bi-stability and its application to single-shot readout in circuit quantum electrodynamics

    Science.gov (United States)

    Sun, Luyan; Ginossar, Eran; Guy, Mikhael; Reed, Matthew; Paik, Hanhee; Bishop, Lev S.; Sears, Adam; Petrenko, Andrei; Brecht, Teresa; Frunzio, Luigi; Girvin, Steven; Schoelkopf, Robert

    2012-02-01

    The high power transient behavior of superconducting qubit-cavity systems has recently been used to perform high fidelity readout of transmon qubits [1]. We show that in the steady state, the system exhibits a bi-stable behavior that can be observed on the single-shot level, with the cavity state switching stochastically between dim and bright states. The switching times are shown to be long compared to the cavity and qubit lifetimes. Some features of the bi-stability can be explained by mean field theory, while its switching dynamics is studied with large scale simulations. Understanding these dynamics will be crucial for studying the transient response, an essential aspect of the qubit readout. We will discuss progress on optimizing readout by shaping the measurement pulse. [4pt] [1] M. D. Reed, L. DiCarlo, B. R. Johnson, L. Sun, D. I. Schuster, L. Frunzio, and R. J. Schoelkopf, Phys. Rev. Lett. 105, 173601 (2010)

  10. Shot Automation for the National Ignition Facility

    International Nuclear Information System (INIS)

    Lagin, L J; Bettenhausen, R C; Beeler, R G; Bowers, G A; Carey, R.; Casavant, D.D.; Cline, B.D.; Demaret, R.D.; Domyancic, D.M.; Elko, S.D.; Fisher, J.M.; Hermann, M.R.; Krammen, J.E.; Kohut, T.R.; Marshall, C.D.; Mathisen, D.G.; Ludwigsen, A.P.; Patterson, Jr. R.W.; Sanchez, R.J.; Stout, E.A.; Van Arsdall, P.J.; Van Wonterghem, B.M.

    2005-01-01

    A shot automation framework has been developed and deployed during the past year to automate shots performed on the National Ignition Facility (NIF) using the Integrated Computer Control System This framework automates a 4-8 hour shot sequence, that includes inputting shot goals from a physics model, set up of the laser and diagnostics, automatic alignment of laser beams and verification of status. This sequence consists of set of preparatory verification shots, leading to amplified system shots using a 4-minute countdown, triggering during the last 2 seconds using a high-precision timing system, followed by post-shot analysis and archiving. The framework provides for a flexible, model-based execution driven of scriptable automation called macro steps. The framework is driven by high-level shot director software that provides a restricted set of shot life cycle state transitions to 25 collaboration supervisors that automate 8-laser beams (bundles) and a common set of shared resources. Each collaboration supervisor commands approximately 10 subsystem shot supervisors that perform automated control and status verification. Collaboration supervisors translate shot life cycle state commands from the shot director into sequences of ''macro steps'' to be distributed to each of its shot supervisors. Each Shot supervisor maintains order of macro steps for each subsystem and supports collaboration between macro steps. They also manage failure, restarts and rejoining into the shot cycle (if necessary) and manage auto/manual macro step execution and collaborations between other collaboration supervisors. Shot supervisors execute macro step shot functions commanded by collaboration supervisors. Each macro step has database-driven verification phases and a scripted perform phase. This provides for a highly flexible methodology for performing a variety of NIF shot types. Database tables define the order of work and dependencies (workflow) of macro steps to be performed for a

  11. Fast and robust automatic calibration for single-shot dual-wavelength digital holography based on speckle displacements.

    Science.gov (United States)

    Khodadad, Davood; Bergström, Per; Hällstig, Emil; Sjödahl, Mikael

    2015-06-01

    The objective of this paper is to describe a fast and robust automatic single-shot dual-wavelength holographic calibration method that can be used for online shape measurement applications. We present a model of the correction in two terms for each lobe, one to compensate the systematic errors caused by off-axis angles and the other for the curvature of the reference waves, respectively. Each hologram is calibrated independently without a need for an iterative procedure or information of the experimental set-up. The calibration parameters are extracted directly from speckle displacements between different reconstruction planes. The parameters can be defined as any fraction of a pixel to avoid the effect of quantization. Using the speckle displacements, problems associated with phase wrapping is avoided. The procedure is shown to give a shape accuracy of 34 μm using a synthetic wavelength of 1.1 mm for a measurement on a cylindrical test object with a trace over a field of view of 18  mm×18  mm.

  12. Silicon-Vacancy Spin Qubit in Diamond: A Quantum Memory Exceeding 10 ms with Single-Shot State Readout

    Science.gov (United States)

    Sukachev, D. D.; Sipahigil, A.; Nguyen, C. T.; Bhaskar, M. K.; Evans, R. E.; Jelezko, F.; Lukin, M. D.

    2017-12-01

    The negatively charged silicon-vacancy (SiV- ) color center in diamond has recently emerged as a promising system for quantum photonics. Its symmetry-protected optical transitions enable the creation of indistinguishable emitter arrays and deterministic coupling to nanophotonic devices. Despite this, the longest coherence time associated with its electronic spin achieved to date (˜250 ns ) has been limited by coupling to acoustic phonons. We demonstrate coherent control and suppression of phonon-induced dephasing of the SiV- electronic spin coherence by 5 orders of magnitude by operating at temperatures below 500 mK. By aligning the magnetic field along the SiV- symmetry axis, we demonstrate spin-conserving optical transitions and single-shot readout of the SiV- spin with 89% fidelity. Coherent control of the SiV- spin with microwave fields is used to demonstrate a spin coherence time T2 of 13 ms and a spin relaxation time T1 exceeding 1 s at 100 mK. These results establish the SiV- as a promising solid-state candidate for the realization of quantum networks.

  13. Single-shot T1 mapping of the corpus callosum: A rapid characterization of fiber bundle anatomy

    Directory of Open Access Journals (Sweden)

    Sabine eHofer

    2015-05-01

    Full Text Available Using diffusion-tensor MRI and fiber tractography the topographic organization of the corpus callosum (CC has been described to comprise 5 segments with fibers projecting into prefrontal (I, premotor and supplementary motor (II, primary motor (III, and primary sensory areas (IV, as well as into parietal, temporal, and occipital cortical areas (V. In order to more rapidly characterize the underlying anatomy of these segments, this study used a novel single-shot T1 mapping method to quantitatively determine T1 relaxation times in the human CC. A region-of-interest analysis revealed a tendency for the lowest T1 relaxation times in the genu and the highest T1 relaxation times in the somatomotor region of the CC. This observation separates regions dominated by myelinated fibers with large diameters (somatomotor area from densely packed smaller axonal bundles (genu with less myelin. The results indicate that characteristic T1 relaxation times in callosal profiles provide an additional means to monitor differences in fiber anatomy, fiber density, and gray matter in respective neocortical areas. In conclusion, rapid T1 mapping allows for a characterization of the axonal architecture in an individual CC in less than 10 s. The approach emerges as a valuable means for studying neocortical brain anatomy with possible implications for the diagnosis of neurodegenerative processes.

  14. MR imaging of the gastrointestinal tract with half-fourier single-shot fast spin echo (SSFSE)

    International Nuclear Information System (INIS)

    Boku, Houjun; Takehara, Yasuo; Isoda, Haruo; Isogai, Satoshi; Kaneko, Masao

    1999-01-01

    Our objective was to implement a non-invasive magnetic resonance imaging (MRI) technique combined with concentrated milk ingestion for depicting the gastrointestinal (GI) tract and detecting gastrointestinal motility and transit. The half-Fourier SSFSE (single-shot fast spin echo) sequence was optimized on the basis of a phantom study. In order to determine the feasibility of milk ingestion as a substitute for contrast medium, ten human volunteers were examined with SSFSE after two types of liquid ingestion (i.e., milk and water). The snapshot images provided subsecond data acquisition for each coronal plane, allowing visualization of peristalsis in the gastrointestinal tract in an almost real-time fashion, without motion-related image degradation, as would normally be seen using conventional MRI. There was no significant difference between concentrated milk and water in terms of depiction of the upper gastrointestinal tract; however, 10 min and 30 min after ingestion, concentrated milk showed better delineation of the intestine than that observed after water ingestion (p<0.01). MR gastrointestinal imaging is a non-invasive method that allows gastrointestinal depiction as well as analysis of motility and passage. Especially with concentrated milk ingestion, the distal intestines were well depicted with adequate contrast filling and distention. (author)

  15. MR imaging of the gastrointestinal tract with half-fourier single-shot fast spin echo (SSFSE)

    Energy Technology Data Exchange (ETDEWEB)

    Boku, Houjun; Takehara, Yasuo; Isoda, Haruo; Isogai, Satoshi; Kaneko, Masao [Hamamatsu Univ. School of Medicine, Shizuoka (Japan)

    1999-04-01

    Our objective was to implement a non-invasive magnetic resonance imaging (MRI) technique combined with concentrated milk ingestion for depicting the gastrointestinal (GI) tract and detecting gastrointestinal motility and transit. The half-Fourier SSFSE (single-shot fast spin echo) sequence was optimized on the basis of a phantom study. In order to determine the feasibility of milk ingestion as a substitute for contrast medium, ten human volunteers were examined with SSFSE after two types of liquid ingestion (i.e., milk and water). The snapshot images provided subsecond data acquisition for each coronal plane, allowing visualization of peristalsis in the gastrointestinal tract in an almost real-time fashion, without motion-related image degradation, as would normally be seen using conventional MRI. There was no significant difference between concentrated milk and water in terms of depiction of the upper gastrointestinal tract; however, 10 min and 30 min after ingestion, concentrated milk showed better delineation of the intestine than that observed after water ingestion (p<0.01). MR gastrointestinal imaging is a non-invasive method that allows gastrointestinal depiction as well as analysis of motility and passage. Especially with concentrated milk ingestion, the distal intestines were well depicted with adequate contrast filling and distention. (author)

  16. Tracking Quantum Jumps of Light with Repeated Single-Shot Parity Measurements

    Science.gov (United States)

    Sun, Luyan; Petrenko, Andrei; Leghtas, Zaki; Vlastakis, Brian; Kirchmair, Gerhard; Sliwa, Katrina; Narla, Anirudh; Hatridge, Michael; Shankar, Shyam; Blumoff, Jacob; Frunzio, Luigi; Mirrahimi, Mazyar; Devoret, Michel; Schoelkopf, Robert

    2014-03-01

    Quantum error correction (QEC) is required for a practical quantum computer because of the fragile nature of quantum information. A measurement-based QEC requires the measurement of error syndromes in a quantum non-demolition way and at a rate which is faster than errors occur. In a 3D circuit quantum electrodynamics architecture, we realize a parity measurement of a microwave field with about 90% fidelity by mapping its parity onto an ancilla qubit. The projective nature of the parity measurement onto a degenerate parity eigenspace, the cat states, is confirmed by Wigner tomography after a single parity measurement, showing 84% fidelity to ideal cats. The parity can therefore serve as an error syndrome for a recently proposed QEC scheme [Leghtas et.al. PRL (2013)]. We then demonstrate a tracking of quantum jumps of this error syndrome by repeated parity measurements. We will also discuss a quantum filter developed to mitigate the imperfections during the parity measurement for a best estimate of the photon state parity. The demonstrated extraction of error syndromes without perturbing the encoded information is essential for QEC. Current address: CQI, IIIS, Tsinghua University, Beijing, China.

  17. Gradient ROtating Outer Volume Excitation (GROOVE): A Novel Method for Single-Shot 2-D OVS

    Science.gov (United States)

    Powell, Nathaniel J.; Jang, Albert; Park, Jang-Yeon; Valette, Julien; Garwood, Michael; Marjańska, Małgorzata

    2014-01-01

    Purpose A new outer volume suppression (OVS) technique is introduced that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called Gradient ROtating Outer Volume Excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing the entire outer volume. Methods Theoretical and k-space descriptions of GROOVE are provided. The properties of GROOVE were investigated with simulations, phantom, and human experiments performed using a 4 T horizontal bore magnet equipped with a TEM coil. Results Similar suppression performance was obtained in phantom and human brain using GROOVE with circular and elliptical shapes. Simulations indicate that GROOVE requires less SAR and time than traditional OVS schemes, but traditional schemes provide a sharper transition zone and less residual signal. Conclusion GROOVE represents a new way of performing OVS in which spins are excited temporally in space on a trajectory which can be tailored to fit the shape of the suppression region. In addition, GROOVE is capable of suppressing tailored regions of space with more flexibility and in a shorter period of time than conventional methods. GROOVE provides a fast, low SAR alternative to conventional OVS methods in some applications (e.g., scalp suppression). PMID:24478130

  18. Gene delivery process in a single animal cell after femtosecond laser microinjection

    Science.gov (United States)

    Hosokawa, Yoichiroh; Iguchi, Seriya; Yasukuni, Ryohei; Hiraki, Yuji; Shukunami, Chisa; Masuhara, Hiroshi

    2009-09-01

    Microinjection of extracellular molecules into a single animal cell was performed by an amplified femtosecond laser irradiation. When a single-shot laser pulse was focused on the plasma membrane of a single fibroblast from the mouse cell line NIH3T3 with a high-numerical aperture objective lens, a transient hole with a diameter of 1 μm was formed. The delivery process of extracellular molecules immediately after the hole formation was monitored by a fluorescence staining with fluoresceinisothiocyanate-dextran (FITC-dextran). Then the gene expression was confirmed using a DNA plasmid of an enhanced green fluorescent protein (EGFP). The gene expression was observed when the laser pulse was focused first on the cellular membrane and then on the nuclear membrane, while the gene was not expressed when the laser was focused only on the cellular membrane. On the basis of these results, the efficiency of gene delivery by the femtosecond laser microinjection and the subsequent gene expression were clarified.

  19. Utility of single shot fast spin echo technique in evaluating pancreaticobiliary diseases: T2-weighted image and magnetic resonance cholangiopancreatography

    International Nuclear Information System (INIS)

    Choi, Byoung Wook; Kim, Myeong Jin; Chung, Jae Bok; Ko, Heung Kyu; Kim, Dong Joon; Kim, Joo Hee; Chung, Jae Joon; Yoo, Hyung Sik; Lee, Jong Tae

    1999-01-01

    To evaluate the accuracy of T2-weighted imaging an MR cholangiopancreatography using the single shot fast spin-echo technique for evaluating pancreaticobiliary disease. Between March and July 1997, axial and coronal T2-weighted images(TE: 80-200 msec) and MR cholangiopancreatograms (TE: 800-1200 msec) were obtained in two ways [single slab (thickness: 30-50 mm) and multislice acquisition under chemical fat saturation] using SSFSE pulse sequencing in 131 cases of suspected pancreati-cobiliary disease. The accuracy of SSFSE MR imaging was assessed in 89 lesions of 74 patients [male, 48; female, 26; age range, 30-86 (mean, 59) years] confirmed surgicopathologically (50 lesions in 39 patients) and clinically (39 lesions in 35 patients). Two radiologists reviewed the MR images and diagnosis was determined by consensus. Correct diagnosis was confirmed in 84 of 89 lesions (94%). Seven lesions were falsely interpreted, false positive and false negative results accounting for two and five cases, respectively. Two pancreatic cancers were misdiagnosed as pancreatitis and a cancer of the proximal common bile duct(CBD) was interpreted as a distal CBD cancer. The sensitivity of SSFSE MR imaging for malignancy was 93 %. One CBD stone revealed by endoscopic retrograde cholangiopancreatography (ERCP) was not detected on MR images. In contrast, a stone in the CBD seen on MR images was not apparent on subsequent ERCP. Sensitivity and specificity for calculous disease were 96% and 99.7%, respectively. A benign stricture of the ampulla of Vater was falsely interpreted as normal, and correct diagnosis was possible in two falsely diagnosed cases when MR images were reviewed retrospectively. The combination of T2-weighted and cholangiographic images using SSFSE is an accurate method for diagnosing pancreatcobiliary diseases

  20. Laser induced single spot oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jwad, Tahseen, E-mail: taj355@bham.ac.uk; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-11-30

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  1. Laser induced single spot oxidation of titanium

    International Nuclear Information System (INIS)

    Jwad, Tahseen; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-01-01

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  2. Non-contrast-enhanced imaging of haemodialysis fistulas using quiescent-interval single-shot (QISS) MRA: a feasibility study

    International Nuclear Information System (INIS)

    Okur, A.; Kantarci, M.; Karaca, L.; Yildiz, S.; Sade, R.; Pirimoglu, B.; Keles, M.; Avci, A.; Çankaya, E.; Schmitt, P.

    2016-01-01

    Aim: To assess the efficiency of a novel quiescent-interval single-shot (QISS) technique for non-contrast-enhanced magnetic resonance angiography (MRA) of haemodialysis fistulas. Materials and methods: QISS MRA and colour Doppler ultrasound (CDU) images were obtained from 22 haemodialysis patients with end-stage renal disease (ESRD). A radiologist with extensive experience in vascular imaging initially assessed the fistulas using CDU. Two observers analysed each QISS MRA data set in terms of image quality, using a five-point scale ranging from 0 (non-diagnostic) to 4 (excellent), and lumen diameters of all segments were measured. Results: One hundred vascular segments were analysed for QISS MRA. Two anastomosis segments were considered non-diagnostic. None of the arterial or venous segments were evaluated as non-diagnostic. The image quality was poorer for the anastomosis level compared to the other segments (p<0.001 for arterial segments, and p<0.05 for venous segments), while no significant difference was determined for other vascular segments. Conclusion: QISS MRA has the potential to provide valuable complementary information to CDU regarding the imaging of haemodialysis fistulas. In addition, QISS non-enhanced MRA represents an alternative for assessment of haemodialysis fistulas, in which the administration of iodinated or gadolinium-based contrast agents is contraindicated. - Highlights: • Close monitoring and early intervention in hemodialysis fistulas may prolong longevity fistulas. • DopplerUS, contrast enhanced CT and MRI are using assessment of hemodialysis fistulas. • QISS nonenhanced MR angiography represents an alternative for assessment of hemodialysis fistulas.

  3. Increasing shot and data collection rates of the Shock/Shear experiment at the National Ignition Facility

    International Nuclear Information System (INIS)

    Doss, F. W.; Flippo, K. A.; Capelli, D.; Cardenas, T.; DeVolder, B.; Kline, J.; Kot, L.; Kurien, S.; Loomis, E.; Merritt, E. C.; Perry, T.; Schmidt, D.; Di Stefano, C.

    2016-01-01

    Updates to the Los Alamos laser-driven high-energy-density Shock/Shear mixing- layer experiment are reported, which have collectively increased the platform's shot and data acquisition rates. The strategies employed have included a move from two-strip to four-strip imagers (allowing four times to be recorded per shot instead of two), the implementation of physics-informed rules of engagements allowing for the maximum flexibility in a shot's total energy and symmetry performance, and splitting the laser's main drive pulse from a monolithic single pulse equal to all beams into a triply-segmented pulse which minimizes optics damage. (paper)

  4. Active-passively mode-locked dye laser for diagnosis of laser-produced plasmas

    International Nuclear Information System (INIS)

    Teng, Y.L.; Fedosejevs, R.; Sigel, R.

    1981-03-01

    In this report an active-passively mode-locked, flashlamp-pumped dye laser for diagnosis of laser-produced plasmas is described. This dye laser system used as a pulsed light source for high-speed photography of laser-target experiments was synchronized to the ASTERIX III iodine laser pulse with better than 100 ps accuracy. The single pulse energy was 10 μJ, pulse duration less than 10 ps. In 111 shots clear shadowgrams were obtained during a total of 151 target shots, i.e. the system worked well in 74% of the shots. (orig.)

  5. Indirect monitoring shot-to-shot shock waves strength reproducibility during pump–probe experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pikuz, T. A., E-mail: tatiana.pikuz@eie.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 Japan (Japan); Photon Pioneers Center, Osaka University, Suita, Osaka 565-0871 Japan (Japan); Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Faenov, A. Ya. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Institute for Academic Initiatives, Osaka University, Suita, Osaka 565-0871 (Japan); Ozaki, N.; Habara, H.; Tanaka, K. A.; Kodama, R. [Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 Japan (Japan); Photon Pioneers Center, Osaka University, Suita, Osaka 565-0871 Japan (Japan); Hartley, N. J.; Matsuoka, T. [Institute for Academic Initiatives, Osaka University, Suita, Osaka 565-0871 (Japan); Albertazzi, B.; Matsuyama, S.; Yamauchi, K.; Ochante, R. [Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 Japan (Japan); Takahashi, K.; Sueda, K. [Photon Pioneers Center, Osaka University, Suita, Osaka 565-0871 Japan (Japan); Tange, Y. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); Sakata, O. [Synchrotron X-ray Station at SPring-8, NIMS, Sayo, Hyogo 679-5148 (Japan); Sekine, T.; Sato, T.; Umeda, Y. [Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan); Inubushi, Y. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); RIKEN Spring-8 Center, Sayo, Hyogo 679-5148 Japan (Japan); and others

    2016-07-21

    We present an indirect method of estimating the strength of a shock wave, allowing on line monitoring of its reproducibility in each laser shot. This method is based on a shot-to-shot measurement of the X-ray emission from the ablated plasma by a high resolution, spatially resolved focusing spectrometer. An optical pump laser with energy of 1.0 J and pulse duration of ∼660 ps was used to irradiate solid targets or foils with various thicknesses containing Oxygen, Aluminum, Iron, and Tantalum. The high sensitivity and resolving power of the X-ray spectrometer allowed spectra to be obtained on each laser shot and to control fluctuations of the spectral intensity emitted by different plasmas with an accuracy of ∼2%, implying an accuracy in the derived electron plasma temperature of 5%–10% in pump–probe high energy density science experiments. At nano- and sub-nanosecond duration of laser pulse with relatively low laser intensities and ratio Z/A ∼ 0.5, the electron temperature follows T{sub e} ∼ I{sub las}{sup 2/3}. Thus, measurements of the electron plasma temperature allow indirect estimation of the laser flux on the target and control its shot-to-shot fluctuation. Knowing the laser flux intensity and its fluctuation gives us the possibility of monitoring shot-to-shot reproducibility of shock wave strength generation with high accuracy.

  6. Remote Raman spectra of benzene obtained from 217 meters using a single 532 nm laser pulse.

    Science.gov (United States)

    Chen, Teng; Madey, John M J; Price, Frank M; Sharma, Shiv K; Lienert, Barry

    2007-06-01

    This report describes a mobile Raman lidar system that has been developed for spectral measurements of samples located remotely at ranges of hundreds of meters. The performance of this system has been quantitatively verified in a lidar calibration experiment using a hard target of standardized reflectance. A new record in detection range was achieved for remote Raman systems using 532 nm laser excitation. Specifically, Raman spectra of liquid benzene were measured with an integration time corresponding to a single 532 nm laser pulse at a distance of 217 meters. The single-shot Raman spectra at 217 meters demonstrated high signal-to-noise ratio and good resolution sufficient for the unambiguous identification of the samples of interest. The transmitter consists of a 20 Hz Nd:YAG laser emitting at 532 nm and 1064 nm and a 178 mm telescope through the use of which allows the system to produce a focused beam at the target location. The receiver consists of a large custom telescope (609 mm aperture) and a Czerny-Turner monochromator equipped with two fast photomultiplier tubes.

  7. Diffusion-weighted MRI of the cervical spinal cord using a single-shot fast spin-echo technique: findings in normal subjects and in myelomalacia

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K.; Katase, S.; Fujikawa, A.; Hachiya, J. [Department of Radiology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, 181-8611, Tokyo (Japan); Kanazawa, H. [Toshiba Corporation, 1-1-1 Shibaura, Minato-ku, 105-8001, Tokyo (Japan); Yodo, K. [Toshiba Medical Systems, 3-26-5 Hongo, Bunkyo-ku, 113-8456, Tokyo (Japan)

    2003-02-01

    We have implemented a new diffusion-weighted MRI (DWI) sequence based on the single-shot fast spin-echo technique. We hypothesised that this would add information to conventional MRI for diagnosis of lesions of the cervical spinal cord. DWI was performed using a technique in which echo collection after the application of motion-probing gradients was done in the same manner as in the single-shot fast spin-echo technique. We first imaged six healthy volunteers to demonstrate the cervical spinal cord using the sequence. Then we applied the sequence to 12 patients with cervical myelomalacia due to chronic cord compression. The spinal cord was well seen in all subjects without the distortion associated with echo-planar DWI. In the patients, lesions appeared as areas of low- or isointense signal on DWI. Calculated apparent diffusion coefficients of the lesions (3.30{+-}0.38 x 10{sup -3} mm{sup 2}/s) were significantly higher than those of normal volunteers (2.26{+-}0.08 x 10{sup -3} mm{sup 2}/s). Increased diffusion in areas of cervical myelomalacia, suggesting irreversible damage, can be detected using this technique. (orig.)

  8. Single mode operation of a TEA CO2 laser

    International Nuclear Information System (INIS)

    Wada, Kazuhiro; Tunawaki, Yoshiaki; Yamanaka, Masanobu.

    1993-01-01

    Single mode operation of a TEA CO 2 laser was performed by using an optical system of Fox-Smith type. Laser beam was taken out from the cavity by using a beam splitter, and was reflected by a mirror back to the cavity. By inserting a Fabry-Perot etalon between the splitter and the mirror, beat of laser pulses can be removed completly. (author)

  9. A single-shot T2mapping protocol based on echo-split gradient-spin-echo acquisition and parametric multiplexed sensitivity encoding based on projection onto convex sets reconstruction.

    Science.gov (United States)

    Chu, Mei-Lan; Chang, Hing-Chiu; Oshio, Koichi; Chen, Nan-Kuei

    2018-01-01

    To develop a high-speed T 2 mapping protocol that is capable of accurately measuring T 2 relaxation time constants from a single-shot acquisition. A new echo-split single-shot gradient-spin-echo (GRASE) pulse sequence is developed to acquire multicontrast data while suppressing signals from most nonprimary echo pathways in Carr-Purcell-Meiboom-Gill (CPMG) echoes. Residual nonprimary pathway signals are taken into consideration when performing T 2 mapping using a parametric multiplexed sensitivity encoding based on projection onto convex sets (parametric-POCSMUSE) reconstruction method that incorporates extended phase graph modeling of GRASE signals. The single-shot echo-split GRASE-based T 2 mapping procedure was evaluated in human studies at 3 Tesla. The acquired data were compared with reference data obtained with a more time-consuming interleaved spin-echo echo planar imaging protocol. T 2 maps derived from conventional single-shot GRASE scans, in which nonprimary echo pathways were not appropriately addressed, were also evaluated. Using the developed single-shot T 2 mapping protocol, quantitatively accurate T 2 maps can be obtained with a short scan time (parametric-POCSMUSE reconstruction. Magn Reson Med 79:383-393, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  10. Synthesis of single walled carbon nanotubes by dual laser vaporization

    CSIR Research Space (South Africa)

    Moodley, MK et al.

    2006-02-27

    Full Text Available Single-walled carbon nanotubes were synthesised by the laser vaporisation of graphite composite targets in a tube furnace. Two pulsed Nd:YAG lasers operating at fundamental (1 064 nm) and 2nd harmonic (532 nm) were combined, focused and evaporated...

  11. Highly Resolved Mg/Ca Depth Profiles of Planktic Foraminifer test Walls Using Single shot Measurements of fs-LA-ICPMS

    Science.gov (United States)

    Jochum, K. P.; Schiebel, R.; Stoll, B.; Weis, U.; Haug, G. H.

    2017-12-01

    Foraminifers are sensitive archives of changes in climate and marine environment. It has been shown that the Mg/Ca signal is a suitable proxy of seawater temperature, because the incorporation of Mg depends on ambient water temperature. In contrast to most former studies, where this ratio is determined by solution-based bulk analysis of 20 - 30 specimens, we have investigated Mg/Ca in single specimens and single chambers at high resolution. A new fs-200 nm-LA-ICPMS technique was developed for the µm-sized layered calcite shells. To generate depth profiles with a resolution of about 50 nm/shot, we chose a low fluence of about 0.3 Jcm-2 and performed single shot measurements of the double charged 44Ca++ and the single charged 25Mg+ ions together. Precision (RSD) of the Mg/Ca data is about 5 %. Calibration was performed with the carbonate reference material MACS-3 from the USGS. Our results for different species from the Arabian Sea and Caribbean Sea demonstrate that Mg/Ca of different chambers vary and indicate that the foraminifer individuals built their chambers in different water depths and/or experienced seasonal changes in seawater temperature caused, for example, by upwelling (cold) versus stratified (warm) conditions. Typically, the Mg/Ca ratios of the final two chambers of the planktic foraminifer Globorotalia menardii from a sediment core of the Arabian Sea differ by about 5 mmol/mol from earlier chambers (2 mmol/mol) corresponding to seawater temperatures of 28 °C and 18 °C, respectively. In addition, mass fractions of other elements like Sr, Mn, Fe, Ba, and U have been determined with fs-LA-ICPMS using fast line scans, and thus provide further insights in the ecology of foraminifers.

  12. 1.26 Single Frequency Fiber Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative compact, high power, and extremely reliable 1.26 micron Ho-doped single frequency fiber laser. The proposed...

  13. 1.26 Single Frequency Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative compact, high power, and extremely reliable 1.26 micron Ho-doped single frequency fiber laser. The proposed...

  14. Single mode dye-doped polymer photonic crystal lasers

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Buss, Thomas; Smith, Cameron

    2010-01-01

    Dye-doped polymer photonic crystal (PhC) lasers fabricated by combined nanoimprint and photolithography are studied for their reproducibility and stability characteristics. We introduce a phase shift in the PhC lattice that substantially improves the yield of single wavelength emission. Single mode...... emission and reproducibility of laser characteristics are important if the lasers are to be mass produced in, e. g., optofluidic sensor chips. The fabrication yield is above 85% with highly reproducible wavelengths (within 0.5%), and the temperature dependence on the wavelength is found to be -0.045 or -0...

  15. Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

    Science.gov (United States)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-01-01

    A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

  16. Dependence of single-shot pulse durations on near-infrared filamentation-guided breakdown in air

    Directory of Open Access Journals (Sweden)

    Andreas Schmitt-Sody

    2017-03-01

    Full Text Available We present results of an experimental investigation of laser pulsewidth dependence of filamentation-guided high voltage breakdown in air. The experiments are conducted at laser peak power levels of 1 TW and pulse durations of 0.7 to 10 ps with a discharge gap separation of 10 cm. Synchronized electrical and optical diagnostic techniques were used to determine the pulsewidth dependence on the breakdown mechanism, threshold levels, time delays and associated jitter. The results indicate that longer pulses provide greater than 30% reduction in breakdown threshold voltage.

  17. Single-shot characterization of enzymatic reaction constants Km and kcat by an acoustic-driven, bubble-based fast micromixer

    Science.gov (United States)

    Xie, Yuliang; Ahmed, Daniel; Lapsley, Michael Ian; Lin, Sz-Chin Steven; Nawaz, Ahmad Ahsan; Wang, Lin; Huang, Tony Jun

    2014-01-01

    In this work we present an acoustofluidic approach for rapid, single-shot characterization of enzymatic reaction constants Km and kcat. The acoustofluidic design involves a bubble anchored in a horseshoe structure which can be stimulated by a piezoelectric transducer to generate vortices in the fluid. The enzyme and substrate can thus be mixed rapidly, within 100 ms, by the vortices to yield the product. Enzymatic reaction constants Km and kcat can then be obtained from the reaction rate curves for different concentrations of substrate while holding the enzyme concentration constant. We studied the enzymatic reaction for β-galactosidase and its substrate (resorufin β-D-galactopyranoside) and found Km and kcat to be 333±130 =M and 64±8 s−1 respectively, which are in agreement with published data. Our approach is valuable for studying the kinetics of high-speed enzymatic reactions and other chemical reactions. PMID:22880882

  18. Single-shot all-optical sampling oscilloscope using a polarization-maintaining resonator for pulse replication

    Czech Academy of Sciences Publication Activity Database

    Komanec, M.; Honzátko, Pavel; Zvánovec, S.

    2010-01-01

    Roč. 52, č. 11 (2010), s. 2452-2456 ISSN 0895-2477 R&D Projects: GA AV ČR 1ET300670502 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical sampling oscilloscope * four-wave mixing * fiber pulse replicator * highly nonlinear fiber Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.656, year: 2010

  19. Clinical single-shot diffusion-weighted MRI of the human brain on a short-bore medium-field imager

    International Nuclear Information System (INIS)

    Loevblad, K.O.; Remonda, L.; Schneider, J.; Goenner, F.; Schroth, G.; Heid, O.

    1999-01-01

    Diffusion-weighted MRI (DWI) is becoming important for assessment of acute stroke. Until recently single-shot DWI required expensive technology such as echo-planar imaging (EPI) available only at some research sites. A new medium-field (1.0 T) short-bore MR imager has been developed with which DWI data sets can be acquired. We prospectively studied 169 patients on this 1.0 T commercial system. After conventional imaging, DWI was performed with a single-shot multi-slice sequence with b values 0 an 900 s/mm 2 , and with the gradients switched in three directions. The apparent diffusion coefficients were calculated with online calculation software. There were 50 patients with totally normal MRI, and 17 had strokes, these strokes were detected as areas of high signal on the images at a maximal b value. There was a drop in the ADC in ischaemic regions: in subacute infarcts, the values were between 0.41 and 0.531 x 10 - 3 mm 2 /s. In old infarcts the ADC was 1.15 x 10 - 3 mm 2 /s. Cerebrospinal fluid (CSF) gave low signal whereas areas in the brain had more intermediate intensities (CSF: 3.00; deep white matter: 0.75, cortical grey matter: 0.80, basal ganglia (thalamus): 0.70 and cerebellar white matter: 0.65 x 10 - 3 mm 2 /s). Anisotropy was detected as areas of restricted diffusion along the tracts. These preliminary data show that DWI can be aquired successfully on a medium-field short-bore system. This should allow the technique to be implemented at more sites, therefore facilitating the diagnosis of acute stroke and rendering early intervention feasible. (orig.)

  20. Single-Mode, Distributed Feedback Interband Cascade Lasers

    Science.gov (United States)

    Frez, Clifford F. (Inventor); Borgentun, Carl E. (Inventor); Briggs, Ryan M. (Inventor); Bagheri, Mahmood (Inventor); Forouhar, Siamak (Inventor)

    2016-01-01

    Single-mode, distributed feedback interband cascade lasers (ICLs) using distributed-feedback gratings (e.g., lateral Bragg gratings) and methods of fabricating such ICLs are provided. The ICLs incorporate distributed-feedback gratings that are formed above the laser active region and adjacent the ridge waveguide (RWG) of the ICL. The ICLs may incorporate a double-ridge system comprising an optical confinement structure (e.g., a RWG) disposed above the laser active region that comprises the first ridge of the double ridge system, a DFB grating (e.g., lateral Bragg grating) disposed above the laser active region and adjacent the optical confinement structure, and an electric confinement structure that passes at least partially through the laser active region and that defines the boundary of the second ridge comprises and the termination of the DFB grating.

  1. Atmospheric pressure nitrogen laser made by single block ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuchuan; Wang Huaiming; Rao Deyi; Yan Zhicheng; Ge Qian; Li Yue; Zhang Yilu; Xie Yan

    1986-02-01

    This paper reports the experimental research for atmospheric pressure nitrogen laser of short tube design, with a single block ceramics as dielectric. With the laser discharge electrode 5.8 cm in length, we got pulse energy of 13 ..mu..J at 100 Hz, with a maximum average power of 1.3 mW, a pulse width of 0.8 ns, and a beam divergence of 1.3 x 3 mrad.

  2. High power laser interaction with single and double layer targets

    Czech Academy of Sciences Publication Activity Database

    Borodziuk, S.; Demchenko, N. N.; Gus'kov, S. Yu.; Jungwirth, Karel; Kálal, M.; Kasperczuk, A.; Kondrashov, V. N.; Králiková, Božena; Krouský, Eduard; Limpouch, Jiří; Mašek, Karel; Pisarczyk, P.; Pisarczyk, T.; Pfeifer, Miroslav; Rohlena, Karel; Rozanov, V. B.; Skála, Jiří; Ullschmied, Jiří

    2005-01-01

    Roč. 35, č. 2 (2005), s. 241-262 ISSN 0078-5466 R&D Projects: GA MŠk(CZ) LN00A100; GA AV ČR(CZ) KSK2043105 Grant - others:EU(XE) HPRI-CT-1999-00053; RFBR(RU) 02-02-16966; IAEA(XE) 11655/RBF; INTAS(XX) 01-0572 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : laser produced plasma * three-frame interferometry * macroparticle * single and double targets * crater * shock wave * laser energy absorption Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.459, year: 2005

  3. Coherence properties of a single-mode polariton laser

    Science.gov (United States)

    Kim, Seonghoon; Zhang, Bo; Wang, Zhaorong; Deng, Hui; Fischer, Julian; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Hofling, Sven; Univ of Michigan-Ann Arbor Collaboration; Univ of Wuerzberg Collaboration

    2016-05-01

    Exciton-polariton condensation is a promising low threshold coherent light source, namely a polariton laser. However, first- and second-order coherences of a polariton laser has been poor and not well understood in two dimensional microcavity systems. Here, we show experimentally that full second-order coherence is established in a single-mode polariton laser and maintained far above the lasing threshold. The coherence time of first-order coherence functions increases initially and then reduces as the number of polaritons in a ground state increases due to the polariton-polariton interaction. Moreover, a transition in spectral lineshape from Lorentzian to Gaussian was observed as the occupation number increases as a result of the large interaction energy. These results are in very good agreement with a single-mode atom laser theory. The single-mode polariton laser was realized by designing a subwavelength grating (SWG) mirror which provides strong lateral confinement for discrete polariton states and polarization-selective reflectance for lifted spin-degeneracy. The results would be important for making fully coherent polariton lasers, as well as nonlinear polariton devices.

  4. Focal liver lesion detection and characterization: Comparison of non-contrast enhanced and SPIO-enhanced diffusion-weighted single-shot spin echo echo planar and turbo spin echo T2-weighted imaging

    NARCIS (Netherlands)

    Coenegrachts, Kenneth; Matos, Celso; ter Beek, Léon; Metens, Thierry; Haspeslagh, Marc; Bipat, Shandra; Stoker, Jaap; Rigauts, Hans

    2009-01-01

    Purpose: To compare lesion conspicuity and image quality between single-shot spin echo echo planar imaging (SS SE-EPI) before, immediately and 5 min after intravenous (IV) injection of superparamagnetic iron oxide (SPIO) for detecting and characterizing focal liver lesions (FLLs). Materials and

  5. 1540-nm single frequency single-mode pulsed all fiber laser for coherent Doppler lidar

    Science.gov (United States)

    Zhang, Xin; Diao, Weifeng; Liu, Yuan; Liu, Jiqiao; Hou, Xia; Chen, Weibiao

    2015-02-01

    A single-mode single frequency eye-safe pulsed all fiber laser based on master oscillator power amplification structure is presented. This laser is composed of a narrow linewidth distributed laser diode seed laser and two-stage cascade amplifiers. 0.8 m longitudinally gradient strained erbium/ytterbium co-doped polarization-maintaining fiber with a core diameter of 10 μm is used as the gain fiber and two acoustic-optics modulators are adopted to enhance pulse extinction ratio. A peak power of 160 W and a pulse width of 200 ns at 10 kHz repetition rate are achieved with transform-limited linewidth and diffraction-limited beam quality. This laser will be employed in a compact short range coherent Doppler wind lidar.

  6. Allergy Shots (For Parents)

    Science.gov (United States)

    ... animal dander. Allergy shots are not useful for food allergies. When receiving allergy shots, a child may experience ... Allergies First Aid: Allergic Reactions Insect Sting Allergy Food Allergies Serious Allergic Reactions (Anaphylaxis) Word! Allergy Word! Allergy ...

  7. X-ray pulse preserving single-shot optical cross-correlation method for improved experimental temporal resolution

    International Nuclear Information System (INIS)

    Beye, M.; Krupin, O.; Hays, G.; Jong, S. de; Lee, S.; Coffee, R.; Holmes, M. R.; Fry, A. R.; White, W. E.; Bostedt, C.; Schlotter, W. F.; Reid, A. H.; Rupp, D.; Lee, W.-S.; Scherz, A. O.; Chuang, Y.-D.; Cryan, J. P.; Glownia, J. M.; Foehlisch, A.; Durr, H. A.

    2012-01-01

    We measured the relative arrival time between an optical pulse and a soft x-ray pulse from a free-electron laser. This femtosecond cross-correlation measurement was achieved by observing the change in optical reflectivity induced through the absorption of a fraction of the x-ray pulse. The main x-ray pulse energy remained available for an independent pump-probe experiment where the sample may be opaque to soft x-rays. The method was employed to correct the two-pulse delay data from a canonical pump-probe experiment and demonstrate 130 ± 20 fs (FWHM) temporal resolution. We further analyze possible timing jitter sources and point to future improvements.

  8. Shot peening speed measurements using lidar technology

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Zhang, Xiaodan; Sjöholm, Mikael

    The shot peening technique is used for the surface modification of metallic components that are part of wind turbines, such as gears, bolts and blade coatings to prevent erosion. An important parameter of this technique is the dynamic energy of emitted shots. In this context the objective...... of this project is to present a proof of concept measurement method for the evaluation of the speed of the shots. A remote sensing laser anemometer was selected as a probing instrument of the peening shots’ speed since it avoids any disturbances to the flow from the presence of an in-situ instrument. Furthermore...

  9. Birth Control Shot

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Birth Control Shot KidsHealth / For Teens / Birth Control Shot What's in this article? What Is ... español La inyección anticonceptiva What Is It? The birth control shot is a long-acting form of ...

  10. Optimization of mass spectrometric parameters improve the identification performance of capillary zone electrophoresis for single-shot bottom-up proteomics analysis.

    Science.gov (United States)

    Zhang, Zhenbin; Dovichi, Norman J

    2018-02-25

    The effects of MS1 injection time, MS2 injection time, dynamic exclusion time, intensity threshold, and isolation width were investigated on the numbers of peptide and protein identifications for single-shot bottom-up proteomics analysis using CZE-MS/MS analysis of a Xenopus laevis tryptic digest. An electrokinetically pumped nanospray interface was used to couple a linear-polyacrylamide coated capillary to a Q Exactive HF mass spectrometer. A sensitive method that used a 1.4 Th isolation width, 60,000 MS2 resolution, 110 ms MS2 injection time, and a top 7 fragmentation produced the largest number of identifications when the CZE loading amount was less than 100 ng. A programmable autogain control method (pAGC) that used a 1.4 Th isolation width, 15,000 MS2 resolution, 110 ms MS2 injection time, and top 10 fragmentation produced the largest number of identifications for CZE loading amounts greater than 100 ng; 7218 unique peptides and 1653 protein groups were identified from 200 ng by using the pAGC method. The effect of mass spectrometer conditions on the performance of UPLC-MS/MS was also investigated. A fast method that used a 1.4 Th isolation width, 30,000 MS2 resolution, 45 ms MS2 injection time, and top 12 fragmentation produced the largest number of identifications for 200 ng UPLC loading amount (6025 unique peptides and 1501 protein groups). This is the first report where the identification number for CZE surpasses that of the UPLC at the 200 ng loading level. However, more peptides (11476) and protein groups (2378) were identified by using UPLC-MS/MS when the sample loading amount was increased to 2 μg with the fast method. To exploit the fast scan speed of the Q-Exactive HF mass spectrometer, higher sample loading amounts are required for single-shot bottom-up proteomics analysis using CZE-MS/MS. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. [In-phase and out-of-phase single-shot magnetization-prepared gradient recalled echo: description and optimization of technique at 1.5 T].

    Science.gov (United States)

    Ramalho, M; Herédia, V; de Campos, R O P; de Toni, M; Dale, B M; Semelka, R C

    2014-01-01

    To implement in-phase and out-of-phase (IP/OP) techniques with Magnetization-Prepared Gradient Recalled Echo (MP-GRE) and to evaluate the feasibility and diagnostic image quality among pre and post-optimized MP-GRE sequences, including patients unable to cooperate with breath-hold requirements. Institutional review board approval with waiver of informed consent was obtained for this HIPAA-compliant retrospective study. Two groups of patients were included in the study, before and after optimization of MP-GRE parameters, with seventy-three (24 noncooperative/49 cooperative) and sixty-four (22 noncooperative/42 cooperative) consecutive patients, respectively. The motion-insensitive sequence used in this study was a single-shot 2D MP-GRE. Two radiologists qualitatively evaluated the sequences to identify the presence of phase cancellation artifact in OP images and to determine image quality, extent of artifacts (respiratory ghosting, bounce-point artifact, spatial misregistration and pixel graininess) and lesion conspicuity on the various sequences. The ability to visually detect liver steatosis and fatty adrenal adenomas was evaluated. Qualitative analyses were compared using the Wilcoxon and Mann-Whitney tests. There were statistically significant differences between all MP-GRE sequences concerning phase cancellation artifact (P<.0001) which was present in MP-GRE OP sequences and negligible to absent in the pre (IP1) and post-optimized (IP2) MP-GRE IP sequences, respectively, in all patients. Bounce point artifacts were significantly more pronounced in MP-GRE IP1 (P<.0001). Spatial misregistration was slightly more prominent in noncooperative patients with MP-GRE IP2 (P=.0027). MP-GRE OP and MP-GRE IP2 showed significantly higher overall image quality (P<.0001). MP-GRE sequences subjectively identified hepatic steatosis (n=20) and adrenal adenomas (n=5) based on signal loss from IP to OP sequence. Single shot IP/OP MP-GRE is feasible and allows motion resistant

  12. Single shot spinal anesthesia with very low hyperbaric bupivacaine dose (3.75 mg) for hip fracture repair surgery in the elderly. A randomized, double blinded study.

    Science.gov (United States)

    Errando, C L; Peiró, C M; Gimeno, A; Soriano, J L

    2014-11-01

    Single shot spinal anesthesia is used worldwide for hip fracture repair surgery in the elderly. Arterial hypotension is a frequent adverse effect. We hypothesized that lowering local anesthetics dose could decrease the incidence of arterial hypotension, while maintaining quality of surgical anesthesia. In a randomized double blinded study, 66 patients over the age of 65 years, with hip fracture needing surgical repair, were assigned to B0.5 group 7.5mg hyperbaric bupivacaine 5mg/ml (control group), and B0.25 group 3.75mg hyperbaric bupivacaine 2.5mg/ml (study group). Sensory and motor block level, and hemodynamic parameters including blood presure, heart rate and vasopressor dose administration were registered, along with rescue anesthesia needs, the feasibility of surgery, its duration, and regression time of sensory anesthesia to T12. After exclusions, 61 patients were included in the final analysis. Arterial hypotension incidence was lower in the B0.25 group (at the 5, 10, and 15min determinations), and a lower amount of vasopressor drugs was needed (mean accumulated ephedrine dose 1.6mg vs. 8.7mg in the B0.5 group, p<0.002). Sensory block regression time to T12 was shorter in the B0.25 group, mean 78.6±23.6 (95% CI 51.7-110.2)min vs. 125.5±37.9 (95% CI 101.7-169.4)min in the B0.5 group, p=0.033. All but one patient in the B0.25 group were operated on under the anesthetic procedure first intended. No rescue anesthesia was needed. Lowering bupivacaine dose for single shot spinal anesthesia for hip fracture repair surgery in elderly patients was effective in decreasing the occurrence of arterial hypotension and vasopressor use, while intraoperative quality remained. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. LOPUT Laser: A novel concept to realize single longitudinal mode ...

    Indian Academy of Sciences (India)

    2014-02-05

    Feb 5, 2014 ... Contributed Papers Volume 82 Issue 2 February 2014 pp 185-190 ... Abstract. We propose a novel type of cavity design to generate single longitudinal mode laser known as LOPUT cavity. LOPUT cavity stands for linear orthogonally polarized modes resulting in unidirectional travelling wave cavity.

  14. Single scan vector prediction in selective laser melting

    NARCIS (Netherlands)

    Wits, Wessel Willems; Bruins, R.; Terpstra, L.; Huls, R.A.; Geijselaers, Hubertus J.M.

    2015-01-01

    In selective laser melting (SLM) products are built by melting layers of metal powder successively. Optimal process parameters are usually obtained by scanning single vectors and subsequently determining which settings lead to a good compromise between product density and build speed. This paper

  15. Single track and single layer formation in selective laser melting of niobium solid solution alloy

    Directory of Open Access Journals (Sweden)

    Yueling GUO

    2018-04-01

    Full Text Available Selective laser melting (SLM was employed to fabricate Nb-37Ti-13Cr-2Al-1Si (at% alloy, using pre-alloyed powders prepared by plasma rotating electrode processing (PREP. A series of single tracks and single layers under different processing parameters was manufactured to evaluate the processing feasibility by SLM, including laser power, scanning speed, and hatch distance. Results showed that continuous single tracks could be fabricated using proper laser powers and scanning velocities. Both the width of a single track and its penetration depth into a substrate increased with an increase of the linear laser beam energy density (LED, i.e., an increase of the laser power and a decrease of the scanning speed. Nb, Ti, Si, Cr, and Al elements distributed heterogeneously over the melt pool in the form of swirl-like patterns. An excess of the hatch distance was not able to interconnect neighboring tracks. Under improper processing parameters, a balling phenomenon occurred, but could be eliminated with an increased LED. This work testified the SLM-processing feasibility of Nb-based alloy and promoted the application of SLM to the manufacture of niobium-based alloys. Keywords: Additive manufacturing, Melt pool, Niobium alloy, Powder metallurgy, Selective laser melting

  16. Treating Acute Insomnia: A Randomized Controlled Trial of a "Single-Shot" of Cognitive Behavioral Therapy for Insomnia.

    Science.gov (United States)

    Ellis, Jason G; Cushing, Toby; Germain, Anne

    2015-06-01

    Despite considerable evidence supporting cognitive behavioral therapy for insomnia (CBT-I) for chronic insomnia, it remains untested within the context of acute insomnia. This study examined the efficacy of a single session of CBT-I, with an accompanying self-help pamphlet, for individuals with acute insomnia. A pragmatic parallel group randomized controlled trial. Community. Forty adults (mean age 32.9 ± 13.72 y) with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) defined insomnia disorder, except a self-reported duration of less than 3 mo (i.e., acute insomnia), who reported no previous exposure to CBT-I and were not currently taking medication for sleep. A single 60- to 70-min session of CBT-I (n = 20), with an accompanying self-help pamphlet, or wait list control group (n = 20). All subjects were offered a full individual course of CBT-I on completion of the study, regardless of group allocation. Subjects completed sleep diaries and the Insomnia Severity Index (ISI) pretreatment and 1 mo following treatment. There were no between-group differences on baseline ISI scores or subjective sleep continuity. The intervention group reported significantly lower ISI scores than controls (t(38) 2.24, P insomnia caseness (i.e., ≥ 10), 60% of those in the CBT-I group had remitted by 1 mo compared to 15% of those in the control group. This single session of cognitive behavioral therapy for insomnia (CBT-I) is sufficiently efficacious for a significant proportion of those with acute insomnia. The results are discussed in terms of integrating this brief form of CBT-I into the "stepped care" model of insomnia. Testing the efficacy of an early intervention for acute insomnia (SRCTN05891695) http://www.controlled-trials.com/ISRCTN05891695. © 2015 Associated Professional Sleep Societies, LLC.

  17. Integration of an Optical Ring Resonator Biosensor into a Self-Contained Microfluidic Cartridge with Active, Single-Shot Micropumps

    Directory of Open Access Journals (Sweden)

    Sascha Geidel

    2016-09-01

    Full Text Available While there have been huge advances in the field of biosensors during the last decade, their integration into a microfluidic environment avoiding external tubing and pumping is still neglected. Herein, we show a new microfluidic design that integrates multiple reservoirs for reagent storage and single-use electrochemical pumps for time-controlled delivery of the liquids. The cartridge has been tested and validated with a silicon nitride-based photonic biosensor incorporating multiple optical ring resonators as sensing elements and an immunoassay as a potential target application. Based on experimental results obtained with a demonstration model, subcomponents were designed and existing protocols were adapted. The newly-designed microfluidic cartridges and photonic sensors were separately characterized on a technical basis and performed well. Afterwards, the sensor was functionalized for a protein detection. The microfluidic cartridge was loaded with the necessary assay reagents. The integrated pumps were programmed to drive the single process steps of an immunoassay. The prototype worked selectively, but only with a low sensitivity. Further work must be carried out to optimize biofunctionalization of the optical ring resonators and to have a more suitable flow velocity progression to enhance the system’s reproducibility.

  18. Kerr-lens mode-locked Ti:Sapphire laser pumped by a single laser diode

    Science.gov (United States)

    Kopylov, D. A.; Esaulkov, M. N.; Kuritsyn, I. I.; Mavritskiy, A. O.; Perminov, B. E.; Konyashchenko, A. V.; Murzina, T. V.; Maydykovskiy, A. I.

    2018-04-01

    The performance of a Ti:sapphire laser pumped by a single 461 nm laser diode is presented for both the continuous-wave and the mode-locked regimes of operation. We introduce a simple astigmatism correction scheme for the laser diode beam consisting of two cylindrical lenses affecting the pump beam along the fast axis of the laser diode, which provides the mode-matching between the nearly square-shaped pump beam and the cavity mode. The resulting efficiency of the suggested Ti:Sapphire oscillator pumped by such a laser diode is analyzed for the Ti:sapphire crystals of 3 mm, 5 mm and 10 mm in length. We demonstrate that such a system provides the generation of ultrashort pulses up to 15 fs in duration with the repetition rate of 87 MHz, the average power being 170 mW.

  19. Low-field single-sided NMR for one-shot 1D-mapping: Application to membranes

    Science.gov (United States)

    Judeinstein, Patrick; Ferdeghini, Filippo; Oliveira-Silva, Rodrigo; Zanotti, Jean-Marc; Sakellariou, Dimitrios

    2017-04-01

    Many single-sided permanent magnet NMR systems have been proposed over the years allowing for 1D proton-density profiling, diffusion measurements and relaxometry. In this manuscript we make use of a recently published unilateral magnet for low-field NMR exhibiting an extremely uniform magnetic field gradient with moderate strength and cylindrical symmetry, allowing for a well-defined sweet spot. Combined with a goniometer, our system is used to characterize precisely the uniformity of its gradient and to achieve micrometric precision 1D profiling, as well as spatially localized relaxometry and diffusometry on thick (∼150 μm) membrane samples. Profiling with this magnet did not require repositioning of the samples with respect to the 1D tomograph.

  20. Nonenhanced ECG-gated quiescent-interval single-shot MRA (QISS-MRA) of the lower extremities: Comparison with contrast-enhanced MRA

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, J. [Department of Diagnostic and Interventional Radiology, University of Duesseldorf, Medical Faculty, Duesseldorf (Germany); Blondin, D., E-mail: blondin@med.uni-duesseldorf.de [Department of Diagnostic and Interventional Radiology, University of Duesseldorf, Medical Faculty, Duesseldorf (Germany); Schmitt, P. [Siemens AG, Healthcare Sector, Erlangen (Germany); Bi, X. [Siemens Healthcare, Chicago, IL (United States); Sansone, R. [Department of Cardiology, University of Duesseldorf, Medical Faculty, Duesseldorf (Germany); Wittsack, H.-J.; Kroepil, P.; Quentin, M.; Kuhlemann, J.; Miese, F. [Department of Diagnostic and Interventional Radiology, University of Duesseldorf, Medical Faculty, Duesseldorf (Germany); Heiss, C.; Kelm, M. [Department of Cardiology, University of Duesseldorf, Medical Faculty, Duesseldorf (Germany); Antoch, G.; Lanzman, R.S. [Department of Diagnostic and Interventional Radiology, University of Duesseldorf, Medical Faculty, Duesseldorf (Germany)

    2012-05-15

    Aim: To evaluate electrocardiogram (ECG)-gated quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) for nonenhanced assessment of peripheral artery occlusive disease (PAOD) using contrast-enhanced MRA (CE-MRA) as the reference standard. Materials and methods: Twenty-seven patients (mean age 66.6 {+-} 10.8 years) with PAOD were included in the study. QISS-MRA and CE-MRA of the lower extremity were performed using a 1.5 T MR scanner. In each patient, subjective image quality and the degree of stenosis were evaluated on a four-point scale for 15 predefined arterial segments. Results: Twenty-five of the 27 patients were considered for analysis. Subjective image quality of QISS-MRA was significantly lower for the distal aorta, pelvic arteries, and femoral arteries as compared to CE-MRA (p < 0.01), while no significant difference was found for other vascular segments. The degree of stenosis was overestimated with QISS-MRA in 23 of 365 (6.3%) segments and underestimated in two of 365 (0.5%) segments. As compared to CE-MRA, QISS-MRA had a high sensitivity (98.6%), specificity (96%) as well as positive and negative predictive value (88.7 and 99.6%, respectively) for the detection of significant stenosis ({>=}50%). Conclusion: ECG-gated QISS-MRA is a promising imaging technique for reliable assessment of PAOD without the use of contrast material.

  1. Single-shot characterization of enzymatic reaction constants Km and kcat by an acoustic-driven, bubble-based fast micromixer.

    Science.gov (United States)

    Xie, Yuliang; Ahmed, Daniel; Lapsley, Michael Ian; Lin, Sz-Chin Steven; Nawaz, Ahmad Ahsan; Wang, Lin; Huang, Tony Jun

    2012-09-04

    In this work we present an acoustofluidic approach for rapid, single-shot characterization of enzymatic reaction constants K(m) and k(cat). The acoustofluidic design involves a bubble anchored in a horseshoe structure which can be stimulated by a piezoelectric transducer to generate vortices in the fluid. The enzyme and substrate can thus be mixed rapidly, within 100 ms, by the vortices to yield the product. Enzymatic reaction constants K(m) and k(cat) can then be obtained from the reaction rate curves for different concentrations of substrate while holding the enzyme concentration constant. We studied the enzymatic reaction for β-galactosidase and its substrate (resorufin-β-D-galactopyranoside) and found K(m) and k(cat) to be 333 ± 130 μM and 64 ± 8 s(-1), respectively, which are in agreement with published data. Our approach is valuable for studying the kinetics of high-speed enzymatic reactions and other chemical reactions.

  2. The value of single-shot turbo spin-echo diffusion-weighted MR imaging in the detection of middle ear cholesteatoma

    International Nuclear Information System (INIS)

    De Foer, Bert; Bernaerts, Anja; Maes, Joachim; Deckers, Filip; Pouillon, Marc; Vercruysse, Jean-Philippe; Somers, Thomas; Offeciers, Erwin; Michiels, Johan; Casselman, Jan W.

    2007-01-01

    Single-shot (SS) turbo spin-echo (TSE) diffusion-weighted (DW) magnetic resonance imaging (MRI) is a non echo-planar imaging (EPI) technique recently reported for the evaluation of middle ear cholesteatoma. We prospectively evaluated a SS TSE DW sequence in detecting congenital or acquired middle ear cholesteatoma and evaluated the size of middle ear cholesteatoma detectable with this sequence. The aim of this study was not to differentiate between inflammatory tissue and cholesteatoma using SS TSE DW imaging. A group of 21 patients strongly suspected clinically and/or otoscopically of having a middle ear cholesteatoma without any history of prior surgery were evaluated with late post-gadolinium MRI including this SS TSE DW sequence. A total of 21 middle ear cholesteatomas (5 congenital and 16 acquired) were found at surgery with a size varying between 2 and 19 mm. Hyperintense signal on SS TSE DW imaging compatible with cholesteatoma was found in 19 patients. One patient showed no hyperintensity due to autoevacuation of the cholesteatoma sac into the external auditory canal. Another patient showed no hyperintensity because of motion artifacts. This study shows the high sensitivity of this SS TSE DW sequence in detecting small middle ear cholesteatomas, with a size limit as small as 2 mm. (orig.)

  3. Silicon-Vacancy Spin Qubit in Diamond: A Quantum Memory Exceeding 10 ms with Single-Shot State Readout.

    Science.gov (United States)

    Sukachev, D D; Sipahigil, A; Nguyen, C T; Bhaskar, M K; Evans, R E; Jelezko, F; Lukin, M D

    2017-12-01

    The negatively charged silicon-vacancy (SiV^{-}) color center in diamond has recently emerged as a promising system for quantum photonics. Its symmetry-protected optical transitions enable the creation of indistinguishable emitter arrays and deterministic coupling to nanophotonic devices. Despite this, the longest coherence time associated with its electronic spin achieved to date (∼250  ns) has been limited by coupling to acoustic phonons. We demonstrate coherent control and suppression of phonon-induced dephasing of the SiV^{-} electronic spin coherence by 5 orders of magnitude by operating at temperatures below 500 mK. By aligning the magnetic field along the SiV^{-} symmetry axis, we demonstrate spin-conserving optical transitions and single-shot readout of the SiV^{-} spin with 89% fidelity. Coherent control of the SiV^{-} spin with microwave fields is used to demonstrate a spin coherence time T_{2} of 13 ms and a spin relaxation time T_{1} exceeding 1 s at 100 mK. These results establish the SiV^{-} as a promising solid-state candidate for the realization of quantum networks.

  4. Readout-Segmented Echo-Planar Imaging in Diffusion-Weighted MR Imaging in Breast Cancer: Comparison with Single-Shot Echo-Planar Imaging in Image Quality

    International Nuclear Information System (INIS)

    Kim, Yun Ju; Kim, Sung Hun; Kang, Bong Joo; Park, Chang Suk; Kim, Hyeon Sook; Son, Yo Han; Porter, David Andrew; Song, Byung Joo

    2014-01-01

    The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast

  5. Nonenhanced ECG-gated quiescent-interval single-shot MRA (QISS-MRA) of the lower extremities: Comparison with contrast-enhanced MRA

    International Nuclear Information System (INIS)

    Klasen, J.; Blondin, D.; Schmitt, P.; Bi, X.; Sansone, R.; Wittsack, H.-J.; Kröpil, P.; Quentin, M.; Kuhlemann, J.; Miese, F.; Heiss, C.; Kelm, M.; Antoch, G.; Lanzman, R.S.

    2012-01-01

    Aim: To evaluate electrocardiogram (ECG)-gated quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) for nonenhanced assessment of peripheral artery occlusive disease (PAOD) using contrast-enhanced MRA (CE-MRA) as the reference standard. Materials and methods: Twenty-seven patients (mean age 66.6 ± 10.8 years) with PAOD were included in the study. QISS-MRA and CE-MRA of the lower extremity were performed using a 1.5 T MR scanner. In each patient, subjective image quality and the degree of stenosis were evaluated on a four-point scale for 15 predefined arterial segments. Results: Twenty-five of the 27 patients were considered for analysis. Subjective image quality of QISS-MRA was significantly lower for the distal aorta, pelvic arteries, and femoral arteries as compared to CE-MRA (p < 0.01), while no significant difference was found for other vascular segments. The degree of stenosis was overestimated with QISS-MRA in 23 of 365 (6.3%) segments and underestimated in two of 365 (0.5%) segments. As compared to CE-MRA, QISS-MRA had a high sensitivity (98.6%), specificity (96%) as well as positive and negative predictive value (88.7 and 99.6%, respectively) for the detection of significant stenosis (≥50%). Conclusion: ECG-gated QISS-MRA is a promising imaging technique for reliable assessment of PAOD without the use of contrast material.

  6. Label-free nanoscale characterization of red blood cell structure and dynamics using single-shot transport of intensity equation

    Science.gov (United States)

    Poola, Praveen Kumar; John, Renu

    2017-10-01

    We report the results of characterization of red blood cell (RBC) structure and its dynamics with nanometric sensitivity using transport of intensity equation microscopy (TIEM). Conventional transport of intensity technique requires three intensity images and hence is not suitable for studying real-time dynamics of live biological samples. However, assuming the sample to be homogeneous, phase retrieval using transport of intensity equation has been demonstrated with single defocused measurement with x-rays. We adopt this technique for quantitative phase light microscopy of homogenous cells like RBCs. The main merits of this technique are its simplicity, cost-effectiveness, and ease of implementation on a conventional microscope. The phase information can be easily merged with regular bright-field and fluorescence images to provide multidimensional (three-dimensional spatial and temporal) information without any extra complexity in the setup. The phase measurement from the TIEM has been characterized using polymeric microbeads and the noise stability of the system has been analyzed. We explore the structure and real-time dynamics of RBCs and the subdomain membrane fluctuations using this technique.

  7. Gradient rotating outer volume excitation (GROOVE): A novel method for single-shot two-dimensional outer volume suppression.

    Science.gov (United States)

    Powell, Nathaniel J; Jang, Albert; Park, Jang-Yeon; Valette, Julien; Garwood, Michael; Marjańska, Małgorzata

    2015-01-01

    To introduce a new outer volume suppression (OVS) technique that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called gradient rotating outer volume excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing the entire outer volume. Theoretical and k-space descriptions of GROOVE are provided. The properties of GROOVE were investigated with simulations, phantom, and human experiments performed using a 4T horizontal bore magnet equipped with a TEM coil. Similar suppression performance was obtained in phantom and human brain using GROOVE with circular and elliptical shapes. Simulations indicate that GROOVE requires less SAR and time than traditional OVS schemes, but traditional schemes provide a sharper transition zone and less residual signal. GROOVE represents a new way of performing OVS in which spins are excited temporally in space on a trajectory that can be tailored to fit the shape of the suppression region. In addition, GROOVE is capable of suppressing tailored regions of space with more flexibility and in a shorter period of time than conventional methods. GROOVE provides a fast, low SAR alternative to conventional OVS methods in some applications (e.g., scalp suppression). © 2014 Wiley Periodicals, Inc.

  8. Imaging Single ZnO Vertical Nanowire Laser Cavities using UV-Laser Scanning Confocal Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gargas, D.J.; Toimil-Molares, M.E.; Yang, P.

    2008-11-17

    We report the fabrication and optical characterization of individual ZnO vertical nanowire laser cavities. Dilute nanowire arrays with interwire spacing>10 ?m were produced by a modified chemical vapor transport (CVT) method yielding an ideal platform for single nanowire imaging and spectroscopy. Lasing characteristics of a single vertical nanowire are presented, as well as high-resolution photoluminescence imaging by UV-laser scanning confocal microscopy. In addition, three-dimensional (3D) mapping of the photoluminescence emission performed in both planar and vertical dimensions demonstrates height-selective imaging useful for vertical nanowires and heteronanostructures emerging in the field of optoelectronics and nanophotonics.

  9. Non-chromatographic preparation of a bacterially produced single-shot modular virus-like particle capsomere vaccine for avian influenza.

    Science.gov (United States)

    Wibowo, Nani; Wu, Yang; Fan, Yuanyuan; Meers, Joanne; Lua, Linda H L; Middelberg, Anton P J

    2015-11-04

    Highly pathogenic avian influenza (HPAI) causes significant economic loss, reduced food security and poses an ongoing pandemic threat. Poultry vaccination significantly decreases these problems and recognizes that the health of humans, animals and ecosystems are connected. Low-cost manufacture of poultry vaccine matched quickly to the ever-changing circulating strain is needed for effective vaccination. Here, we re-engineered the process to manufacture bacterially synthesized modular capsomere comprising influenza M2e, previously shown to confer complete protection in challenged mice, for application in poultry. Modular capsomere was prepared using a simplified non-chromatographic salting-out precipitation method and its immunogenicity tested in vivo in poultry. Modular capsomere crudely purified by precipitation (pCapM2e) contained more contaminants than equivalent product purified by chromatography (cCapM2e). Unadjuvanted pCapM2e containing 80 EU of endotoxin per dose was inferior to highly purified and adjuvanted cCapM2e (2 EU per dose). However, addition of adjuvant to pCapM2e resulting in high immunogenicity after only a single dose of vaccination, yet without any local adverse reaction. This finding suggests a strong synergy between adjuvant, antigen and contaminants, and the possible existence of a "Goldilocks" level of contaminants, where high immunogenicity and low reactogenicity can be obtained in a single-shot vaccination. The simplified process offers potential cost and speed advantages to address the needs in influenza poultry vaccination in low-cost veterinary markets. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Mode Selection for a Single-Frequency Fiber Laser

    Science.gov (United States)

    Liu, Jian

    2010-01-01

    A superstructured fiber-grating-based mode selection filter for a single-frequency fiber laser eliminates all free-space components, and makes the laser truly all-fiber. A ring cavity provides for stable operations in both frequency and power. There is no alignment or realignment required. After the fibers and components are spliced together and packaged, there is no need for specially trained technicians for operation or maintenance. It can be integrated with other modules, such as telescope systems, without extra optical alignment due to the flexibility of the optical fiber. The filter features a narrow line width of 1 kHz and side mode suppression ratio of 65 dB. It provides a high-quality laser for lidar in terms of coherence length and signal-to-noise ratio, which is 20 dB higher than solid-state or microchip lasers. This concept is useful in material processing, medical equipment, biomedical instrumentation, and optical communications. The pulse-shaping fiber laser can be directly used in space, airborne, and satellite applications including lidar, remote sensing, illuminators, and phase-array antenna systems.

  11. Optofluidic lasers with a single molecular layer of gain

    Science.gov (United States)

    Chen, Qiushu; Ritt, Michael; Sivaramakrishnan, Sivaraj; Sun, Yuze; Fan, Xudong

    2014-01-01

    We achieve optofluidic lasers with a single molecular layer of gain, in which green fluorescent protein, dye-labeled bovine serum albumin, and dye-labeled DNA are respectively used as the gain medium and attached to the surface of a ring resonator via surface immobilization biochemical methods. It is estimated that the surface density of the gain molecules is on the order of 1012/cm2, sufficient for lasing under pulsed optical excitation. It is further shown that the optofluidic laser can be tuned by energy transfer mechanisms through biomolecular interactions. This work not only opens a door to novel photonic devices that can be controlled at the level of a single molecular layer, but also provides a promising sensing platform to analyze biochemical processes at the solid-liquid interface. PMID:25312306

  12. Effect of the peening intensity by shot peening

    International Nuclear Information System (INIS)

    Cheong, Seong Kyun; Chung, Suk Choo; Lee, Seung Ho

    2001-01-01

    The shot peening process is most often used to improve fatigue properties of metal parts. The single most critical parameter of the shot peening process is the shot ball itself. Without the correct quality media, all other shot peening parameters are extraneous and the desired fatigue improvement and consistency of improvement will not be achieved. shot peening involves modifications of the surface and subsurface condition of a material that can be described by the change of the residual stresses, the hardness, and the surface roughness. This paper presents the shot peening to optimize the shot ball parameters. The effect of shot peening parameter on the surface roughness, surface hardness and residual stress are investigated

  13. Laser direct micro-machining with top-hat-converted single mode lasers

    Science.gov (United States)

    Homburg, O.; Toennissen, F.; Mitra, T.; Lissotschenko, V.

    2008-02-01

    Laser direct micro-machining processes are used in a variety of industries like inkjet printing, semiconductor processing, solar technology, flat-panel display production and medicine. Various kinds of materials, e.g. ceramics, metals, isolators, oxides, organics and semiconductors are being structured. In most cases pulsed single mode solid state lasers with an inhomogeneous Gaussian beam profile are employed, like YAG lasers and their harmonics. However, the quality and functionality of the generated structures and micro-systems as well as the speed of the process can be improved by the utilization of homogeneous top hat profiles. The beam shaping principle of refractive Gaussian-to-top-hat converters is shown. Compact beam shaper modules based on this principle have been developed - supporting most direct laser micro-machining applications. The resulting process advantages are demonstrated by selected application results, namely the drilling of holes and patterning of trenches for different kinds of materials.

  14. Single mode operation of a tea CO2 laser by a CW CO2 laser radiation injection

    International Nuclear Information System (INIS)

    Silakhori, K.; Soltanmoradi, F.; Behjat, A.; Montazerghaem, M.; Sadr, R.

    2005-01-01

    In this research work, single mode operation based on injection of a CW laser beam into TEA CO 2 laser cavity has been demonstrated. The technique has vast applications in research programs for laser spectroscopy and optical pumping. The observed smooth pulse shapes indicated that the system is operating in a single mode of operation, where no additional PZT mounted elements or other cavity stabilizing devices have been used. In addition, it have been observed that the output energy has not been reduced when the laser was operating in a single mode of operation, compared with the case when the laser is operating in the multi-mode regime

  15. Femtosecond laser fabrication of optofluidic devices for single cell manipulation

    Directory of Open Access Journals (Sweden)

    Bragheri Francesca

    2015-01-01

    Full Text Available In this work we fabricate and validate two optofludic devices for the manipulation and analysis of single cells. The chips are fabricated by femtosecond laser micromachining exploiting the 3D capabilities of the technique and the inherent perfect alignment between microfluidic channels and optical networks. Both devices have been validated by probing the mechanical properties of different cancer cell lines, which are expected to show different elasticity because of their different metastatic potential.

  16. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    International Nuclear Information System (INIS)

    Altaha, Mustafa A.; Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J.; Rick, Manuela; Schmitt, Peter; Wintersperger, Bernd J.

    2017-01-01

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm 2 ) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm 3 ) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  17. Diffusion tensor trace mapping in normal adult brain using single-shot EPI technique: A methodological study of the aging brain

    International Nuclear Information System (INIS)

    Chen, Z.G.; Hindmarsh, T.; Li, T.Q.

    2001-01-01

    Purpose: To quantify age-related changes of the average diffusion coefficient value in normal adult brain using orientation-independent diffusion tensor trace mapping and to address the methodological influences on diffusion quantification. Material and Methods: Fifty-four normal subjects (aged 20-79 years) were studied on a 1.5-T whole-body MR medical unit using a diffusion-weighted single-shot echo-planar imaging technique. Orientation-independent diffusion tensor trace maps were constructed for each subject using diffusion-weighted MR measurements in four different directions using a tetrahedral gradient combination pattern. The global average (including cerebral spinal fluid) and the tissue average of diffusion coefficients in adult brains were determined by analyzing the diffusion coefficient distribution histogram for the entire brain. Methodological influences on the measured diffusion coefficient were also investigated by comparing the results obtained using different experimental settings. Results: Both global and tissue averages of the diffusion coefficient are significantly correlated with age (p<0.03). The global average of the diffusion coefficient increases 3% per decade after the age of 40, whereas the increase in the tissue average of diffusion coefficient is about 1% per decade. Experimental settings for self-diffusion measurements, such as data acquisition methods and number of b-values, can slightly influence the statistical distribution histogram of the diffusion tensor trace and its average value. Conclusion: Increased average diffusion coefficient in adult brains with aging are consistent with findings regarding structural changes in the brain that have been associated with aging. The study also demonstrates that it is desirable to use the same experimental parameters for diffusion coefficient quantification when comparing between different subjects and groups of interest

  18. Faster pediatric 3-T abdominal magnetic resonance imaging: comparison between conventional and variable refocusing flip-angle single-shot fast spin-echo sequences.

    Science.gov (United States)

    Ruangwattanapaisarn, Nichanan; Loening, Andreas M; Saranathan, Manojkumar; Litwiller, Daniel V; Vasanawala, Shreyas S

    2015-06-01

    Single-shot fast spin echo (SSFSE) is particularly appealing in pediatric patients because of its motion robustness. However radiofrequency energy deposition at 3 tesla forces long pauses between slices, leading to longer scans, longer breath-holds and more between-slice motion. We sought to learn whether modulation of the SSFSE refocusing flip-angle train could reduce radiofrequency energy deposition without degrading image quality, thereby reducing inter-slice pauses and overall scan times. We modulated the refocusing flip-angle train for SSFSE to minimize energy deposition while minimizing blurring and motion-related signal loss. In a cohort of 50 consecutive patients (25 boys, mean age 5.5 years, range 1 month to 17 years) referred for abdominal MRI we obtained standard SSFSE and variable refocusing flip-angle (vrfSSFSE) images and recorded sequence scan times. Two readers independently scored the images in blinded, randomized order for noise, tissue contrast, sharpness, artifacts and left lobe hepatic signal uniformity on a four-point scale. The null hypothesis of no difference between SSFSE and vrfSSFSE image-quality was assessed with a Mann-Whitney U test, and the null hypothesis of no scan time difference was assessed with the paired t-test. SSFSE and vrfSSFSE mean acquisition times were 54.3 and 26.2 s, respectively (P-value <0.0001). For each reader, SSFSE and vrfSSFSE noise, tissue contrast, sharpness and artifacts were not significantly different (P-values 0.18-0.86). However, SSFSE had better left lobe hepatic signal uniformity (P < 0.01, both readers). vrfSSFSE is twice as fast as SSFSE, with equivalent image quality with the exception of left hepatic lobe signal heterogeneity.

  19. Faster pediatric 3-T abdominal magnetic resonance imaging: comparison between conventional and variable refocusing flip-angle single-shot fast spin-echo sequences

    International Nuclear Information System (INIS)

    Ruangwattanapaisarn, Nichanan; Loening, Andreas M.; Saranathan, Manojkumar; Vasanawala, Shreyas S.; Litwiller, Daniel V.

    2015-01-01

    Single-shot fast spin echo (SSFSE) is particularly appealing in pediatric patients because of its motion robustness. However radiofrequency energy deposition at 3 tesla forces long pauses between slices, leading to longer scans, longer breath-holds and more between-slice motion. We sought to learn whether modulation of the SSFSE refocusing flip-angle train could reduce radiofrequency energy deposition without degrading image quality, thereby reducing inter-slice pauses and overall scan times. We modulated the refocusing flip-angle train for SSFSE to minimize energy deposition while minimizing blurring and motion-related signal loss. In a cohort of 50 consecutive patients (25 boys, mean age 5.5 years, range 1 month to 17 years) referred for abdominal MRI we obtained standard SSFSE and variable refocusing flip-angle (vrfSSFSE) images and recorded sequence scan times. Two readers independently scored the images in blinded, randomized order for noise, tissue contrast, sharpness, artifacts and left lobe hepatic signal uniformity on a four-point scale. The null hypothesis of no difference between SSFSE and vrfSSFSE image-quality was assessed with a Mann-Whitney U test, and the null hypothesis of no scan time difference was assessed with the paired t-test. SSFSE and vrfSSFSE mean acquisition times were 54.3 and 26.2 s, respectively (P-value <0.0001). For each reader, SSFSE and vrfSSFSE noise, tissue contrast, sharpness and artifacts were not significantly different (P-values 0.18-0.86). However, SSFSE had better left lobe hepatic signal uniformity (P < 0.01, both readers). vrfSSFSE is twice as fast as SSFSE, with equivalent image quality with the exception of left hepatic lobe signal heterogeneity. (orig.)

  20. Comparison of respiratory-triggered 3-D fast spin-echo and single-shot fast spin-echo radial slab MR cholangiopancreatography images in children

    International Nuclear Information System (INIS)

    Chavhan, Govind B.; Almehdar, Abeer; Gupta, Sumeet; Moineddin, Rahim; Babyn, Paul S.

    2013-01-01

    The two most commonly performed magnetic resonance cholangiopancreatography (MRCP) sequences, 3-D fast spin-echo (3-D FSE) and single-shot fast spin-echo radial slabs (radial slabs), have not been compared in children. The purpose of this study was to compare 3-D FSE and radial slabs MRCP sequences on a 3-T scanner to determine their ability to show various segments of pancreaticobiliary tree and presence of artifacts in children. We reviewed 79 consecutive MRCPs performed in 74 children on a 3-T scanner. We noted visibility of major ducts on 3-D FSE and radial slabs. We noted the order of branching of ducts in the right and left hepatic ducts and the degree of visibility of the pancreatic duct. Statistical analysis was performed using McNemar and signed rank tests. There was no significant difference in the visibility of major bile ducts and the order of branching in the right hepatic lobe between sequences. A higher order of branching in the left lobe was seen on radial slabs than 3-D FSE (mean order of branching 2.82 versus 2.27; P-value = 0.0002). The visibility of pancreatic duct was better on radial slabs as compared to 3-D FSE (mean value of 1.53 vs. 0.90; P-value < 0.0001). 3-D FSE sequence was artifact-free in 25/79 (31.6%) MRCP exams as compared to radial slabs, which were artifact-free in 18/79 (22.8%) MRCP exams (P-value = 0.0001). There is no significant difference in the visibility of major bile ducts between 3-D FSE and radial slab MRCP sequences at 3-T in children. However, radial slab MRCP shows a higher order of branching in the left hepatic lobe and superior visibility of the pancreatic duct than 3-D FSE. (orig.)

  1. Faster pediatric 3-T abdominal magnetic resonance imaging: comparison between conventional and variable refocusing flip-angle single-shot fast spin-echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Ruangwattanapaisarn, Nichanan [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Bangkok (Thailand); Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Loening, Andreas M.; Saranathan, Manojkumar; Vasanawala, Shreyas S. [Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Litwiller, Daniel V. [GE Healthcare, Rochester, MN (United States)

    2015-06-15

    Single-shot fast spin echo (SSFSE) is particularly appealing in pediatric patients because of its motion robustness. However radiofrequency energy deposition at 3 tesla forces long pauses between slices, leading to longer scans, longer breath-holds and more between-slice motion. We sought to learn whether modulation of the SSFSE refocusing flip-angle train could reduce radiofrequency energy deposition without degrading image quality, thereby reducing inter-slice pauses and overall scan times. We modulated the refocusing flip-angle train for SSFSE to minimize energy deposition while minimizing blurring and motion-related signal loss. In a cohort of 50 consecutive patients (25 boys, mean age 5.5 years, range 1 month to 17 years) referred for abdominal MRI we obtained standard SSFSE and variable refocusing flip-angle (vrfSSFSE) images and recorded sequence scan times. Two readers independently scored the images in blinded, randomized order for noise, tissue contrast, sharpness, artifacts and left lobe hepatic signal uniformity on a four-point scale. The null hypothesis of no difference between SSFSE and vrfSSFSE image-quality was assessed with a Mann-Whitney U test, and the null hypothesis of no scan time difference was assessed with the paired t-test. SSFSE and vrfSSFSE mean acquisition times were 54.3 and 26.2 s, respectively (P-value <0.0001). For each reader, SSFSE and vrfSSFSE noise, tissue contrast, sharpness and artifacts were not significantly different (P-values 0.18-0.86). However, SSFSE had better left lobe hepatic signal uniformity (P < 0.01, both readers). vrfSSFSE is twice as fast as SSFSE, with equivalent image quality with the exception of left hepatic lobe signal heterogeneity. (orig.)

  2. Non-contrast-enhanced MR angiography in critical limb ischemia: performance of quiescent-interval single-shot (QISS) and TSE-based subtraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Altaha, Mustafa A. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); Jaskolka, Jeffrey D.; Tan, Kongteng; Menezes, Ravi J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Rick, Manuela; Schmitt, Peter [Siemens Healthcare, Erlangen (Germany); Wintersperger, Bernd J. [University Health Network, Department of Medical Imaging, Peter Munk Cardiac Centre, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Toronto General Hospital, Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-03-15

    The aim of this study was to evaluate diagnostic performance of non-contrast-enhanced 2D quiescent-interval single-shot (QISS) and 3D turbo spin-echo (TSE)-based subtraction magnetic resonance angiography (MRA) in the assessment of peripheral arteries in patients with critical limb ischemia (CLI). Nineteen consecutive patients (74 % male, 72.8 ± 9.9 years) with CLI underwent 2D QISS and 3D TSE-based subtraction MRA at 1.5 T. Axial-overlapping QISS MRA (3 mm/2 mm; 1 x 1 mm{sup 2}) covered from the toes to the aortic bifurcation while coronal 3D TSE-based subtraction MRA (1.3 x 1.2 x 1.3 mm{sup 3}) was restricted to the calf only. MRA data sets (two readers) were evaluated for stenosis (≥50 %) and image quality. Results were compared with digital subtraction angiography (DSA). Two hundred and sixty-seven (267) segments were available for MRA-DSA comparison, with a prevalence of stenosis ≥50 % of 41.9 %. QISS MRA was rated as good to excellent in 79.5-96.0 % of segments without any nondiagnostic segments; 89.8-96.1 % of segments in 3D TSE-based subtraction MRA were rated as nondiagnostic or poor. QISS MRA sensitivities and specificities (segmental) were 92 % and 95 %, respectively, for reader one and 81-97 % for reader two. Due to poor image quality of 3D TSE-based subtraction MRA, diagnostic performance measures were not calculated. QISS MRA demonstrates excellent diagnostic performance and higher robustness than 3D TSE-based subtraction MRA in the challenging patient population with CLI. (orig.)

  3. Image quality assessment of single-shot turbo spin echo diffusion-weighted imaging with parallel imaging technique: a phantom study.

    Science.gov (United States)

    Yoshida, Tsukasa; Urikura, Atsushi; Shirata, Kensei; Nakaya, Yoshihiro; Terashima, Shingo; Hosokawa, Yoichiro

    2016-09-01

    This study aimed to evaluate the image quality and apparent diffusion coefficient (ADC) values of single-shot turbo spin echo (TSE) diffusion-weighted (DW) images obtained using a parallel imaging (PI) technique. All measurements were performed on a 3.0-T whole-body MRI system and 32-channel phased-array coil. Signal-to-noise ratio (SNR) and ADC values were measured with a DW imaging (DWI) phantom comprising granulated sugar and agar. The SNRs were calculated using a subtraction method and compared among TSE-DW images at acceleration factors (AFs) of 1-4. Image blur was visually assessed on TSE-DW images of a pin phantom at AFs of 1-4. The ADC values were calculated using DW images with b = 0 and 1000 s mm(-2). The ADC values of TSE-DW images and echo-planar imaging EPI-DW images were compared. The SNRs decreased as AFs increased, despite selecting the shortest echo time. A lower AF caused increased image blur in the phase-encoding direction. The ADC values of TSE-DWI tended to be lower than those of EPI-DWI, and AFs of 3 and 4 yielded variable ADC values on TSE-DW images. TSE-DWI with an AF of 3 or 4 yielded reduced SNRs; in addition, the image noise and artefacts associated with PI technique may have affected ADC measurements, despite improving image blur in the phase-encoding direction. Optimizing the imaging parameters of TSE-DWI is useful for providing good image quality and accurate ADC measurements.

  4. Relativistic electron beams driven by single-cycle laser pulses at kHz repetition rate (Conference Presentation)

    Science.gov (United States)

    Faure, Jérôme; Guénot, Diego; Gustas, Dominykas; Vernier, Aline; Beaurepaire, Benoît; Böhle, Frederik; López-Martens, Rodrigo; Lifschitz, Agustin

    2017-05-01

    Laser-plasma accelerators are usually driven by 100-TW class laser systems with rather low repetition rates. However, recent years have seen the emergence of laser-plasma accelerators operating with kHz lasers and energies lower than 10 mJ. The high repetition-rate is particularly interesting for applications requiring high stability and high signal-to-noise ratio but lower energy electrons. For example, our group recently demonstrated that kHz laser-driven electron beams could be used to capture ultrafast structural dynamics in Silicon nano-membranes via electron diffraction with picosecond resolution. In these first experiments, electrons were injected in the density gradients located at the plasma exit, resulting in rather low energies in the 100 keV range. The electrons being nonrelativistic, the bunch duration quickly becomes picosecond long. Relativistic energies are required to mitigate space charge effects and maintain femtosecond bunches. In this paper, we will show very recent results where electrons are accelerated in laser-driven wakefields to relativistic energies, reaching up to 5 MeV at kHz repetition rate. The electron energy was increased by nearly two orders of magnitude by using single-cycle laser pulses of 3.5 fs, with only 2.5 mJ of energy. Using such short pulses of light allowed us to resonantly excite high amplitude and nonlinear plasma waves at high plasma density, ne=1.5-2×1020 cm-3, in a regime close to the blow-out regime. Electrons had a peaked distribution around 5 MeV, with a relative energy spread of 30 %. Charges in the 100's fC/shot and up to pC/shot where measured depending on plasma density. The electron beam was fairly collimated, 20 mrad divergence at Full Width Half Maximum. The results show remarkable stability of the beam parameters in terms of beam pointing and electron distribution. 3D PIC simulations reproduce the results very well and indicate that electrons are injected by the ionization of Nitrogen atoms, N5+ to N6

  5. Picosecond laser filamentation in air

    Science.gov (United States)

    2016-09-02

    under the terms of the Creative CommonsAttribution 3.0 licence . Any further distribution of this workmustmaintain attribution to the author(s) and the...at the wavelength of 1.053 μm, in a 90 mmdiameter beam. The laser operates in the single-shot regime (one shot in ten minutes). Laser pulses can be...The operator T̂ accounts for the self-steepening and space– time focusing effects [34]. Linear dispersion of air is included in equation (5) via the

  6. ECG-gated quiescent-interval single-shot MR angiography of the lower extremities: Initial experience at 3 T

    International Nuclear Information System (INIS)

    Knobloch, G.; Gielen, M.; Lauff, M.-T.; Romano, V.C.; Schmitt, P.; Rick, M.; Kröncke, T.J.; Huppertz, A.; Hamm, B.; Wagner, M.

    2014-01-01

    Aim: To evaluate the feasibility of unenhanced electrocardiography (ECG)-gated quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) of the lower extremities at 3 T. Materials and methods: Twenty-five patients with known or suspected peripheral arterial disease underwent ECG-gated QISS-MRA and contrast-enhanced MRA (CE-MRA) at 3 T. Two independent readers performed a per-segment evaluation of the MRA datasets. Image quality was rated on a four-point scale (1 = excellent to 4 = non-diagnostic; presented as medians with interquartile range). Diagnostic performance of QISS-MRA was evaluated using CE-MRA as the reference standard. Results: QISS-MRA and CE-MRA of all patients were considered for analysis, resulting in 807 evaluated vessel segments for each MRA technique. Readers 1 and 2 rated image quality of QISS-MRA as diagnostic in 97.3% and 97% of the vessel segments, respectively. CE-MRA was rated diagnostic in all vessel segments. Image quality of the proximal vessel segments, including the infrarenal aorta, iliac arteries, and common femoral artery, was significantly lower on QISS-MRA compared to CE-MRA [image quality score across readers: 2 (1,3) versus 1 (1,1) p < 0.001]. In the more distal vessel segments, image quality of QISS-MRA was excellent and showed no significant difference compared to CE-MRA [image quality score across readers: 1 (1,1) versus 1 (1,1) p = 0.036]. Diagnostic performance of QISS-MRA was as follows (across readers): sensitivity: 87.5% (95% CI: 80.2–92.4%); specificity: 96.1% (95% CI: 93.6–97.6%); diagnostic accuracy: 94.9% (95% CI: 92.6–96.5%). Conclusions: QISS-MRA of the lower extremities is feasible at 3 T and provides high image quality, especially in the distal vessel segments

  7. A multi-channel THz and infrared spectrometer for femtosecond electron bunch diagnostics by single-shot spectroscopy of coherent radiation

    International Nuclear Information System (INIS)

    Wesch, Stephan; Schmidt, Bernhard; Behrens, Christopher; Delsim-Hashemi, Hossein; Schmueser, Peter

    2011-08-01

    The high peak current required in free-electron lasers (FELs) is realized by longitudinal compression of the electron bunches to sub-picosecond length. In this paper, a frequency-domain diagnostic method is described that is capable of resolving structures in the femtosecond regime. A novel in-vacuum spectrometer has been developed for spectroscopy of coherent radiation in the THz and infrared range. The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels; it can be operated either in short wavelength mode (5-44 μm) or in long wavelength mode (45-430 μm). Fast parallel readout permits the spectroscopy of coherent radiation from single electron bunches. Test measurements at the soft X-ray free-electron laser FLASH, using coherent transition radiation, demonstrate excellent performance of the spectrometer. The high sensitivity down to a few micrometers allows study of short bunch features caused for example by microbunching e ects in magnetic chicanes. The device is planned for use as an online bunch profile monitor during regular FEL operation. (orig.)

  8. A multi-channel THz and infrared spectrometer for femtosecond electron bunch diagnostics by single-shot spectroscopy of coherent radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wesch, Stephan; Schmidt, Bernhard; Behrens, Christopher; Delsim-Hashemi, Hossein; Schmueser, Peter

    2011-08-15

    The high peak current required in free-electron lasers (FELs) is realized by longitudinal compression of the electron bunches to sub-picosecond length. In this paper, a frequency-domain diagnostic method is described that is capable of resolving structures in the femtosecond regime. A novel in-vacuum spectrometer has been developed for spectroscopy of coherent radiation in the THz and infrared range. The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels; it can be operated either in short wavelength mode (5-44 {mu}m) or in long wavelength mode (45-430 {mu}m). Fast parallel readout permits the spectroscopy of coherent radiation from single electron bunches. Test measurements at the soft X-ray free-electron laser FLASH, using coherent transition radiation, demonstrate excellent performance of the spectrometer. The high sensitivity down to a few micrometers allows study of short bunch features caused for example by microbunching e ects in magnetic chicanes. The device is planned for use as an online bunch profile monitor during regular FEL operation. (orig.)

  9. Shot-put kinematics

    Science.gov (United States)

    DeLuca, R.

    2005-11-01

    The problem of the optimum throw in the shot-put discipline is analysed by relaxing the assumption that the height H, from which the athlete releases the shot, does not depend on the angle θ which the arm of the putter makes with the horizontal axis. In this context, the kinematics of the shot-put is studied and results are compared with the traditional analysis, which considers the height H, the angle θ and the modulus V0 of the initial velocity of the metal sphere as independent parameters.

  10. Demonstration of Shot-noise-limited Swept Source OCT Without Balanced Detection.

    Science.gov (United States)

    Fathipour, Vala; Schmoll, Tilman; Bonakdar, Alireza; Wheaton, Skylar; Mohseni, Hooman

    2017-04-26

    Optical coherence tomography (OCT) has been utilized in a rapidly growing number of clinical and scientific applications. In particular, swept source OCT (SS-OCT) has attracted many attentions due to its excellent performance. So far however, the limitations of existing photon detectors have prevented achieving shot-noise-limited sensitivity without using balanced-detection scheme in SS-OCT, even when superconducting single-photon detectors were used. Unfortunately, balanced-detection increases OCT system size and cost, as it requires many additional components to boost the laser power and maintain near ideal balanced performance across the whole optical bandwidth. Here we show for the first time that a photon detector is capable of achieving shot noise limited performance without using the balanced-detection technique in SS-OCT. We built a system using a so-called electron-injection photodetector, with a cutoff-wavelength of 1700 nm. Our system achieves a shot-noise-limited sensitivity of about -105 dB at a reference laser power of ~350 nW, which is more than 30 times lower laser power compared with the best-reported results. The high sensitivity of the electron-injection detector allows utilization of micron-scale tunable laser sources (e.g. VCSEL) and eliminates the need for fiber amplifiers and highly precise couplers, which are an essential part of the conventional SS-OCT systems.

  11. Modeling bidirectionally coupled single-mode semiconductor lasers

    International Nuclear Information System (INIS)

    Mulet, Josep; Masoller, Cristina; Mirasso, Claudio R.

    2002-01-01

    We develop a dynamical model suitable for the description of two mutually coupled semiconductor lasers in a face-to-face configuration. Our study considers the propagation of the electric field along the compound system as well as the evolution of the carrier densities within each semiconductor laser. Mutual injection, passive optical feedback, and multiple reflections are accounted for in this framework, although under weak to moderate coupling conditions. We systematically describe the effect of the coupling strength on the spectrum of monochromatic solutions and on the respective dynamical behavior. By assuming single-longitudinal-mode operation, weak mutual coupling and slowly varying approximation, the dynamical model can be reduced to rate equations describing the mutual injection from one laser to its counterpart and vice versa. A good agreement between the complete and simplified models is found for small coupling. For larger coupling, higher-order terms lead to a smaller threshold reduction, reflected itself in the spectrum of the monochromatic solutions and in the dynamics of the optical power

  12. Small Field-of-view single-shot EPI-DWI of the prostate: Evaluation of spatially-tailored two-dimensional radiofrequency excitation pulses.

    Science.gov (United States)

    Attenberger, Ulrike I; Rathmann, Nils; Sertdemir, Metin; Riffel, Philipp; Weidner, Anja; Kannengiesser, Stefan; Morelli, John N; Schoenberg, Stefan O; Hausmann, Daniel

    2016-06-01

    Spatially-tailored (RF) excitation pulses in echo-planar imaging (EPI), combined with a decreased FOV in the phase-encoding direction, enable a reduction of k-space acquisition lines, which shortens the echo train length (ETL) and reduces susceptibility artifacts. The purpose of this study was to evaluate the image quality of a zoomed EPI (z-EPI) sequence in diffusion-weighted imaging (DWI) of the prostate in comparison to a conventional single-shot EPI using single-channel (c-EPI1) and multi-channel (c-EPI2) RF excitation, with and without use of an endorectal coil. 33 consecutive patients (mean age: 61 +/- 9 years; mean PSA: 8.67±6.23 ng/ml) with examinations between 10/2012 and 02/2014 were analyzed in this retrospective study. In 26 of 33 patients the initial multiparametric (mp)-MRI was performed on a whole-body 3T scanner (Magnetom Trio, Siemens, Erlangen, Germany) using an endorectal coil (c (conventional)-EPI1). Zoomed-EPI (Z-EPI) examinations of these patients and a complete mp-MRI protocol including c-EPI2 of 7 additional patients were carried out on another 3T wb MR scanner with two-channel dynamic parallel transmit capability (Magnetom Skyra with TimTX TrueShape, Siemens). For z-EPI, the one-dimensional spatially selective RF excitation pulse was replaced by a two-dimensional RF pulse. Degree of image blur and susceptibility artifacts (0=not present to 3= non-diagnostic), maximum image distortion (mm), apparent diffusion coefficient (ADC) values, as well as overall scan preference were evaluated. SNR maps were generated to compare c-EPI2 and z-EPI. Overall image quality of z-EPI was preferred by both readers in all examinations with a single exception. Susceptibility artifacts were rated significantly lower on z-EPI compared to both other methods (z-EPI vs c-EPI1: p<0.01; z-EPI vs c-EPI2: p<0.01) as well as image blur (z-EPI vs c-EPI1: p<0.01; z-EPI vs c-EPI2: p<0.01). Image distortion was not statistically significantly reduced with z-EPI (z-EPI vs c

  13. A Space-Qualified Single Frequency Fiber Laser for LISA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Single frequency high power lasers have been considered to be an enabling technology for NASA's Laser Interferometer Space Antenna (LISA). PolarOnyx proposes, for...

  14. Tunable High-Power Single-Frequency Laser at 2050 nm, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel new architecture for a low-phase noise electronically tunable laser single-frequency laser at 2.05 microns that meets all the demanding...

  15. Frequency-Locked Single-Frequency Fiber Laser at 2 Micron, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Based on our proprietary fiber technology and extensive experience in fiber laser development, a new single-frequency 2μm fiber laser source will be developed. The...

  16. Laser-induced single point nanowelding of silver nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Shuowei; Li, Qiang, E-mail: qiangli@zju.edu.cn; Liu, Guoping; Yang, Hangbo; Yang, Yuanqing; Zhao, Ding; Wang, Wei; Qiu, Min, E-mail: minqiu@zju.edu.cn [State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2016-03-21

    Nanowelding of nanomaterials opens up an emerging set of applications in transparent conductors, thin-film solar cells, nanocatalysis, cancer therapy, and nanoscale patterning. Single point nanowelding (SPNW) is highly demanded for building complex nanostructures. In this letter, the precise control of SPNW of silver nanowires is explored in depth, where the nanowelding is laser-induced through the plasmonic resonance enhanced photothermal effect. It is shown that the illumination position is a critical factor for the nanowelding process. As an example of performance enhancement, output at wire end can be increased by 65% after welding for a plasmonic nanocoupler. Thus, single point nanowelding technique shows great potentials for high-performance electronic and photonic devices based on nanowires, such as nanoelectronic circuits and plasmonic nanodevices.

  17. Laser-induced single point nanowelding of silver nanowires

    International Nuclear Information System (INIS)

    Dai, Shuowei; Li, Qiang; Liu, Guoping; Yang, Hangbo; Yang, Yuanqing; Zhao, Ding; Wang, Wei; Qiu, Min

    2016-01-01

    Nanowelding of nanomaterials opens up an emerging set of applications in transparent conductors, thin-film solar cells, nanocatalysis, cancer therapy, and nanoscale patterning. Single point nanowelding (SPNW) is highly demanded for building complex nanostructures. In this letter, the precise control of SPNW of silver nanowires is explored in depth, where the nanowelding is laser-induced through the plasmonic resonance enhanced photothermal effect. It is shown that the illumination position is a critical factor for the nanowelding process. As an example of performance enhancement, output at wire end can be increased by 65% after welding for a plasmonic nanocoupler. Thus, single point nanowelding technique shows great potentials for high-performance electronic and photonic devices based on nanowires, such as nanoelectronic circuits and plasmonic nanodevices.

  18. Get Important Shots

    Science.gov (United States)

    ... or older adults Work in a school, hospital, prison, or health clinic Travel outside the United States ... health care reform law passed in 2010, most private insurance plans must cover recommended shots for adults. ...

  19. Shot-to-shot intensity and wavefront stability of high-harmonic generation.

    Science.gov (United States)

    Künzel, S; Williams, G O; Boutu, W; Galtier, E; Barbrel, B; Lee, H J; Nagler, B; Zastrau, U; Dovillaire, G; Lee, R W; Merdji, H; Zeitoun, Ph; Fajardo, M

    2015-05-20

    We report on the shot-to-shot stability of intensity and spatial phase of high-harmonic generation (HHG). The intensity stability is measured for each high-harmonic (HH) order with a spectrometer. Additionally, the spatial phase is measured with an XUV wavefront sensor for a single HH order measured in a single shot, which according to our knowledge was not reported before with a Hartmann wavefront sensor. Furthermore, we compare the single-shot measurement of the spatial phase with time-integrated measurements and we show that the XUV wavefront sensor is a useful tool to simultaneously optimize the spatial phase and intensity of HHG within the available HHG parameter range used in this study.

  20. Intra-Articular, Single-Shot Hylan G-F 20 Hyaluronic Acid Injection Compared with Corticosteroid in Knee Osteoarthritis: A Double-Blind, Randomized Controlled Trial.

    Science.gov (United States)

    Tammachote, Nattapol; Kanitnate, Supakit; Yakumpor, Thanasak; Panichkul, Phonthakorn

    2016-06-01

    The treatment of knee osteoarthritis with hyaluronic acid or corticosteroid injection has been widely used. The purpose of this study was to compare the efficacy of hyaluronic acid (hylan G-F 20) with triamcinolone acetonide as a single intra-articular injection for knee osteoarthritis. This study was a prospective, randomized, double-blind clinical trial. Participants with symptomatic knee osteoarthritis were recruited. They were randomized to receive a single-shot, intra-articular injection of either 6 mL of hylan G-F 20 or 6 mL of a solution comprising 1 mL of 40-mg triamcinolone acetonide and 5 mL of 1% lidocaine with epinephrine. The primary outcomes were knee pain severity, knee function, and range of motion at 6 months. Ninety-nine patients were assessed before injection and underwent a 6-month follow-up. Patients and evaluators were blinded. Multilevel regression models were used to estimate differences between the groups. At the 6-month follow-up, compared with patients who took hylan G-F 20, patients who took triamcinolone acetonide had similar improvement in knee pain, knee function, and range of motion. The difference in mean outcome scores between groups was, with regard to knee pain, a visual analog scale (VAS) score of 3 points (95% confidence interval [95% CI], -6 to 11 points); with regard to knee function, a modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score of 0 points (95% CI, -8 to 6 points); and, with regard to range of motion, flexion of -1° (95% CI, -5° to 2°) and extension of 0° (95% CI, -0.5° to 0.5°). However, patients who took triamcinolone acetonide had better pain improvement from 24 hours until 1 week after injection; the mean difference between groups with regard to the VAS score was 12 points (95% CI, 5 to 20 points; p = 0.002) at 24 hours and 9 points (95% CI, 1 to 15 points; p = 0.018) at 1 week. At 2 weeks after injection, patients who took triamcinolone acetonide also had better knee

  1. Laser damage investigations of Cu mirrors

    International Nuclear Information System (INIS)

    Gorshkov, A.; Bel'bas, I.; Maslov, M.; Sannikov, V.; Vukolov, K.

    2005-01-01

    Laser tests were performed on Cu mirrors as 'first mirror' prototypes for laser diagnostics. Data on laser damage thresholds of surfaces under the influence of pulsed YAG laser radiation were obtained for single shot and after about 1.5 x 10 5 shots. The experiments were carried out using three types of copper mirrors: diamond-turned mirror, diamond-turned substrate with copper coating and reflection grating on a copper coated mirror. The lifetime of the copper mirrors was tested. Diffusion scattering was used as a monitor of mirror surface quality. The degradation of diamond turned copper mirrors in multiple pulse laser irradiation appears to be in satisfactory accordance with a model for multipulse laser damage of metal mirrors up to 1.5 x 10 5 laser pulses. The degradation of copper coated mirrors has a more complicated behaviour

  2. Dye laser spectrometer for the analysis of pulsed vacuum arcs

    International Nuclear Information System (INIS)

    Hargis, P.J. Jr.; Robertson, M.M.

    1975-01-01

    A pulsed dye laser spectrometer which is used to obtain detailed single shot spectroscopic measurements of the plasma in a pulsed vacuum arc was developed. The capabilities of this spectrometer are indicated by the detection of laser induced fluorescence signals from 10 6 neutral Ti atoms in the plasma of a pulsed vacuum arc with a Ti anode. (U.S.)

  3. Shot Noise Thermometry for Thermal Characterization of Templated Carbon Nanotubes

    OpenAIRE

    Sayer, Robert A; Kim, Sunkook; Franklin, Aaron D; Mohammadi, Saeed; Fisher, Timothy

    2010-01-01

    A carbon nanotube (CNT) thermometer that operates on the principles of electrical shot noise is reported. Shot noise thermometry is a self-calibrating measurement technique that relates statistical fluctuations in dc current across a device to temperature. A structure consisting of vertical, top, and bottom-contacted single-walled carbon nanotubes in a porous anodic alumina template was fabricated and used to measure shot noise. Frequencies between 60 and 100 kHz were observed to preclude sig...

  4. Multiple echo multi-shot diffusion sequence.

    Science.gov (United States)

    Chabert, Steren; Galindo, César; Tejos, Cristian; Uribe, Sergio A

    2014-04-01

    To measure both transversal relaxation time (T2 ) and diffusion coefficients within a single scan using a multi-shot approach. Both measurements have drawn interest in many applications, especially in skeletal muscle studies, which have short T2 values. Multiple echo single-shot schemes have been proposed to obtain those variables simultaneously within a single scan, resulting in a reduction of the scanning time. However, one problem with those approaches is the associated long echo read-out. Consequently, the minimum achievable echo time tends to be long, limiting the application of these sequences to tissues with relatively long T2 . To address this problem, we propose to extend the multi-echo sequences using a multi-shot approach, so that to allow shorter echo times. A multi-shot dual-echo EPI sequence with diffusion gradients and echo navigators was modified to include independent diffusion gradients in any of the two echoes. The multi-shot approach allows us to drastically reduce echo times. Results showed a good agreement for the T2 and mean diffusivity measurements with gold standard sequences in phantoms and in vivo data of calf muscles from healthy volunteers. A fast and accurate method is proposed to measure T2 and diffusion coefficients simultaneously, tested in vitro and in healthy volunteers. Copyright © 2013 Wiley Periodicals, Inc.

  5. Interscalene brachial plexus block for open-shoulder surgery: a randomized, double-blind, placebo-controlled trial between single-shot anesthesia and patient-controlled catheter system.

    Science.gov (United States)

    Goebel, Sascha; Stehle, Jens; Schwemmer, Ulrich; Reppenhagen, Stephan; Rath, Beatrice; Gohlke, Frank

    2010-04-01

    Interscalene brachial plexus block (ISB) is widely used as an adjuvant regional pain therapy in patients undergoing major shoulder surgery and has proved its effectiveness on postoperative pain reduction and opioid-sparing effect. This single-center, prospective, double-blind, randomized and placebo-controlled study was to compare the effectiveness of a single-shot and a patient-controlled catheter insertion ISB system after major open-shoulder surgeries. Seventy patients were entered to receive an ISB and a patient-controlled interscalene catheter. The catheter was inserted under ultrasound guidance. Patients were then assigned to receive one of two different postoperative infusions, either 0.2% ropivacaine (catheter group) or normal saline solution (single-shot group) via a disposable patient-controlled infusion pump. The study variables were amount of rescue medication, pain at rest and during physiotherapy, patient satisfaction and incidence of unwanted side effects. The ropivacaine group revealed significantly less consumption of rescue medication within the first 24 h after surgery. Incidence of side effects did not differ between the two groups. Based on our results, we recommend the use of interscalene plexus block in combination with a patient-controlled catheter system under ultrasound guidance only for the first 24 h after major open-shoulder surgery.

  6. Modelling Single Tree Structure with Terrestrial Laser Scanner

    Science.gov (United States)

    Yurtseven, H.; Akgül, M.; Gülci, S.

    2017-11-01

    Recent technological developments, which has reliable accuracy and quality for all engineering works, such as remote sensing tools have wide range use in forestry applications. Last decade, sustainable use and management opportunities of forest resources are favorite topics. Thus, precision of obtained data plays an important role in evaluation of current status of forests' value. The use of aerial and terrestrial laser technology has more reliable and effective models to advance the appropriate natural resource management. This study investigates the use of terrestrial laser scanner (TLS) technology in forestry, and also the methodological data processing stages for tree volume extraction is explained. Z+F Imager 5010C TLS system was used for measure single tree information such as tree height, diameter of breast height, branch volume and canopy closure. In this context more detailed and accurate data can be obtained than conventional inventory sampling in forestry by using TLS systems. However the accuracy of obtained data is up to the experiences of TLS operator in the field. Number of scan stations and its positions are other important factors to reduce noise effect and accurate 3D modelling. The results indicated that the use of point cloud data to extract tree information for forestry applications are promising methodology for precision forestry.

  7. Single-frequency diode-pumped Nd:YAG prism laser with use of a composite laser crystal

    DEFF Research Database (Denmark)

    Pedersen, Christian; Hansen, P. L.; Buchhave, Preben

    1997-01-01

    A compact, stable, diode-pumped Nd:YAG laser suitable for high-power single-frequency operation is investigated theoretically as well as experimentally. Residual spatial hole burning has been eliminated with a unidirectional ring-laser design with a specially designed intracavity prism and a comp...... and a composite YAG laser crystal. A detailed Jones matrix analysis is performed, leading to design criteria for high loss difference and high-frequency stability....

  8. Single-frequency thulium-doped distributed-feedback fibre laser

    DEFF Research Database (Denmark)

    Agger, Søren; Povlsen, Jørn Hedegaard; Varming, Poul

    2004-01-01

    We have successfully demonstrated a single-frequency distributed-feedback (DFB) thulium-doped silica fiber laser emitting at a wavelength of 1735 nm. The laser cavity is less than 5 cm long and is formed by intracore UV-written Bragg gratings with a phase shift. The laser is pumped at 790 nm from...

  9. Critical evaluation of the pulsed laser method for single event effects testing and fundamental studies

    International Nuclear Information System (INIS)

    Melinger, J.S.; Buchner, S.; McMorrow, D.; Stapor, W.J.; Weatherford, T.R.; Campbell, A.B.; Eisen, H.

    1994-01-01

    In this paper the authors present an evaluation of the pulsed laser as a technique for single events effects (SEE) testing. They explore in detail the important optical effects, such as laser beam propagation, surface reflection, and linear and nonlinear absorption, which determine the nature of laser-generated charge tracks in semiconductor materials. While there are differences in the structure of laser- and ion-generated charge tracks, they show that in many cases the pulsed laser remains an invaluable tool for SEE testing. Indeed, for several SEE applications, they show that the pulsed laser method represents a more practical approach than conventional accelerator-based methods

  10. Pulsar radiation as polarized shot noise

    International Nuclear Information System (INIS)

    Cordes, J.M.

    1976-01-01

    Pulsar radiation can be resonably modeled as amplitude-modulated shot noise for which the amplitude modulations correspond to the subpulses and micropulses that comprise the structure of single pulses. The shot noise fluctuates on nanosecond time scales and therefore has a bandwidth typical of pulsars, namely, 1-10 GHz. If curvature radiation from bunches of coherently radiating particles is the relevant radiation mechanism, then the radiation from a single bunch corresponds to a shot pulse; such a physical interpretation is not crucial to the validity of the shot noise model, however. We calculate some statistics of the corresponding signal in a narrow-band receiver system, an informative one being the intensity modulation index of the narrow-band noise from which it can be determined whether or not the noise has Gaussian statistics. Departures from Gaussian statistics can occur if intensity variations are due primarily to changes in the number of particles radiating coherently at any instant. If the temporal density of shot pulses is sufficiently high, however, only Gaussian statistics will be observed, meaning that extensive incoherent addition occurs in the generation and the propagation of the radiation.The first and second moments of the Stokes parameters of narrow-band signals are derived for both time-independent and time-variable polarization. It is shown how the polarization properties of short time scale structure can be determined from the autocorrelation functions of the Stokes parameters

  11. Single-frequency injection-seeded Q-switched Ho:YAG laser

    Science.gov (United States)

    Wang, Qing; Gao, Chunqing; Na, Quanxin; Zhang, Yixuan; Ye, Qing; Gao, Mingwei

    2017-04-01

    An injection-seeded Ho:YAG laser at 2090 nm with changeable pulse repetition frequency (PRF) is demonstrated. Containing a Ho:YAG nonplanar ring oscillator (NPRO) seed, a slave laser, and a single-pass amplifier, the laser delivered single-frequency pulses with energy ranging from 31.4 to 12.7 mJ. The corresponding pulse duration and PRF varied between 102-215 ns and 150-750 Hz, respectively. To the best of our knowledge, this is the highest PRF ever obtained from a single-frequency Ho:YAG laser.

  12. A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui, E-mail: yhzheng@sxu.edu.cn [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)

    2014-01-15

    We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO{sub 4} laser at 1064 nm with coherent output. The measured shot noise of 50 μW laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 μW and 1.52 mW.

  13. Single frequency narrow linewidth 2 micron laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for coherent Lidar applications. The laser should be tunable by several nm and frequency...

  14. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    OpenAIRE

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS)...

  15. Pulsed laser simulation of VLSI single-event effect testing study

    International Nuclear Information System (INIS)

    Xue Yuxiong; Cao Zhou Yang Shiyu; Tian Kai; Liu Shufen; Chu Nan; Cao Haining; Shang Zhi

    2008-01-01

    This paper describes a study aimed at investigating the pulsed laser simulation of Single-Event Effect (SEE) testing for VLSI Intel386EX CPU, using our laboratory LSS (laser simulation system). We have detailed SEE testing principle, testing method, testing system constituting, testing result. It validates that our laser pulses simulate may use SEE testing in VLSI, and Intel 386Ex have a large locking resistance to single event. (authors)

  16. Single-transverse-mode Ti:sapphire rib waveguide laser

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus

    2005-01-01

    Laser operation of Ti:sapphire rib waveguides fabricated using photolithography and ion beam etching in pulsed laser deposited layers is reported. Polarized laser emission was observed at 792.5 nm with an absorbed pump power threshold of 265 mW, which is more than a factor of 2 lower in comparison

  17. SnapShot:Macropinocytosis.

    Science.gov (United States)

    Marques, Pedro E; Grinstein, Sergio; Freeman, Spencer A

    2017-05-04

    Macropinocytosis is the bulk ingestion of extracellular fluids via large endocytic vacuoles. This SnapShot provides an overview of physiological macropinocytosis in immune surveillance and its pathogenic contribution during infection and cancer proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Kids Guide to Shots

    Science.gov (United States)

    ... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body ... Safe Videos for Educators Search English Español A Kid's Guide to Shots KidsHealth / For Kids / A Kid's ...

  19. A systematic examination of the bone destruction pattern of the two-shot technique

    Directory of Open Access Journals (Sweden)

    Marcus Stoetzer

    2014-01-01

    Full Text Available Introduction: The two-shot technique is an effective stopping power method. The precise mechanisms of action on the bone and soft-tissue structures of the skull; however, remain largely unclear. The aim of this study is to compare the terminal ballistics of the two-shot and single-shot techniques. Materials and Methods: 40 fresh pigs′ heads were randomly divided into 4 groups (n = 10. Either a single shot or two shots were fired at each head with a full metal jacket or a semi-jacketed bullet. Using thin-layer computed tomography and photography, the diameter of the destruction pattern and the fractures along the bullet path were then imaged and assessed. Results: A single shot fired with a full metal jacket bullet causes minor lateral destruction along the bullet path. With two shots fired with a full metal jacket bullet, however, the maximum diameter of the bullet path is significantly greater (P < 0.05 than it is with a single shot fired with a full metal jacket bullet. In contrast, the maximum diameter with a semi-jacketed bullet is similar with the single-shot and two-shot techniques. Conclusion: With the two-shot technique, a full metal jacket bullet causes a destruction pattern that is comparable to that of a single shot fired with a semi-jacketed bullet.

  20. Nanosecond pulsed laser ablation of silicon in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Karimzadeh, R.; Anvari, J.Z.; Mansour, N. [Shahid Beheshti University, Department of Physics, Tehran (Iran)

    2009-03-15

    Laser fluence and laser shot number are important parameters for pulse laser based micromachining of silicon in liquids. This paper presents laser-induced ablation of silicon in liquids of the dimethyl sulfoxide (DMSO) and the water at different applied laser fluence levels and laser shot numbers. The experimental results are conducted using 15 ns pulsed laser irradiation at 532 nm. The silicon surface morphology of the irradiated spots has an appearance as one can see in porous formation. The surface morphology exhibits a large number of cavities which indicates as bubble nucleation sites. The observed surface morphology shows that the explosive melt expulsion could be a dominant process for the laser ablation of silicon in liquids using nanosecond pulsed laser irradiation at 532 nm. Silicon surface's ablated diameter growth was measured at different applied laser fluences and shot numbers in both liquid interfaces. A theoretical analysis suggested investigating silicon surface etching in liquid by intense multiple nanosecond laser pulses. It has been assumed that the nanosecond pulsed laser-induced silicon surface modification is due to the process of explosive melt expulsion under the action of the confined plasma-induced pressure or shock wave trapped between the silicon target and the overlying liquid. This analysis allows us to determine the effective lateral interaction zone of ablated solid target related to nanosecond pulsed laser illumination. The theoretical analysis is found in excellent agreement with the experimental measurements of silicon ablated diameter growth in the DMSO and the water interfaces. Multiple-shot laser ablation threshold of silicon is determined. Pulsed energy accumulation model is used to obtain the single-shot ablation threshold of silicon. The smaller ablation threshold value is found in the DMSO, and the incubation effect is also found to be absent. (orig.)

  1. Ultrashort laser pulse driven inverse free electron laser accelerator experiment

    Directory of Open Access Journals (Sweden)

    J. T. Moody

    2016-02-01

    Full Text Available In this paper we discuss the ultrashort pulse high gradient inverse free electron laser accelerator experiment carried out at the Lawrence Livermore National Laboratory which demonstrated gradients exceeding 200  MV/m using a 4 TW 100 fs long 800 nm Ti:Sa laser pulse. Due to the short laser and electron pulse lengths, synchronization was determined to be one of the main challenges in this experiment. This made necessary the implementation of a single-shot, nondestructive, electro-optic sampling based diagnostics to enable time-stamping of each laser accelerator shot with <100  fs accuracy. The results of this experiment are expected to pave the way towards the development of future GeV-class IFEL accelerators.

  2. Lateral emission highly polarized single-mode nanobelt laser (Conference Presentation)

    Science.gov (United States)

    Xu, Pengfei; Liu, Shikai; Li, Ming; Zhou, Zheng; Ren, Zhaohui; Yang, Qing

    2017-02-01

    Nanoscale lasers are the key component in the integrated photonics chips and have attracted much interests. Nanoblets and nanowires lasers, as one of the candidates for the nanoscale lasers, have been developed for one more decades. Many kinds of nanowire lasers with different functionalities, such as wavelength tunable, single mode, polarized emission and so on, have been demonstrated. However, the reported single mode nanowire lasers are mostly realized through microfabrication process, careful manipulation and complicated structures. Here, we present a new type of lateral emission single mode nanobelt lasers with high polarization ratio which are fabricated by the one step traditional VLS (Vapor Liquid Solid) growth. Different from the traditional nanobelt lasers which are based on the FP cavity formed in the longitudinal direction, the emission of this novel nanoblet laser is lateral which is contribute to the special wire-like structures grown on the nanobelt. It shows band edge emission and the wavelength is centered at 712.6 nm with linewidth about 0.18 nm. The threshold reach as low as 15 uJ/cm2 benefit from the unique morphology which provides enhanced confinement factor for optical modes. Meanwhile the laser emission is highly polarized with polarization ration as high as 0.91. This lateral emission single mode nanobelt laser with high polarization ratio, low threshold and simple fabrication technique offers an economic and effective choice to the future optical applications.

  3. Coherent Polariton Laser

    Science.gov (United States)

    Kim, Seonghoon; Zhang, Bo; Wang, Zhaorong; Fischer, Julian; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Höfling, Sven; Deng, Hui

    2016-01-01

    The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.

  4. Coherent Polariton Laser

    Directory of Open Access Journals (Sweden)

    Seonghoon Kim

    2016-03-01

    Full Text Available The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.

  5. ZAPP shot summary

    Energy Technology Data Exchange (ETDEWEB)

    Loisel, Guillaume Pascal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    This was the second Z Astrophysical Plasma Properties (ZAPP) fundamental science shot series of 2015. ZAPP experiments measure fundamental properties of atoms in plasmas to solve the following important astrophysical puzzles: Why can’t we accurately model the opacity of Fe at the convection zone boundary in the Sun? How accurate are the photoionization models used to interpret data from xray satellite observations? and Why doesn’t spectral fitting provide the correct properties for White Dwarfs?

  6. Front-surface fabrication of moderate aspect ratio micro-channels in fused silica by single picosecond Gaussian-Bessel laser pulse

    Science.gov (United States)

    Liu, Xin; Sanner, Nicolas; Sentis, Marc; Stoian, Razvan; Zhao, Wei; Cheng, Guanghua; Utéza, Olivier

    2018-02-01

    Single-shot Gaussian-Bessel laser beams of 1 ps pulse duration and of 0.9 μm core size and 60 μm depth of focus are used for drilling micro-channels on front side of fused silica in ambient condition. Channels ablated at different pulse energies are fully characterized by AFM and post-processing polishing procedures. We identify experimental energy conditions (typically 1.5 µJ) suitable to fabricate non-tapered channels with mean diameter of 1.2 µm and length of 40 μm while maintaining an utmost quality of the front opening of the channels. In addition, by further applying accurate post-polishing procedure, channels with high surface quality and moderate aspect ratio down to a few units are accessible, which would find interest in the surface micro-structuring of materials, with perspective of further scalability to meta-material specifications.

  7. One-shot synesthesia

    Directory of Open Access Journals (Sweden)

    Kirschner Alexandra

    2017-11-01

    Full Text Available Synesthesia is commonly thought to be a phenomenon of fixed associations between an outside inducer and a vivid concurrent experience. Hence, it has been proposed that synesthesia occurs due to additional connections in the brain with which synesthetes are born. Here we show that synesthesia can be a much richer and more flexible phenomenon with a capability to creatively construct novel synesthetic experiences as events unfold in people’s lives. We describe here cases of synesthetes who occasionally generate novel synesthetic experience, called one-shot synesthesias. These synesthetic experiences seem to share all the properties with the classical synesthetic associations except that they occur extremely rarely, people recalling only a few events over the lifetime. It appears that these one-shots are not created at random but are instead responses to specific life events. We contrast the properties of those rare synesthetic events with other, more commonly known forms of synesthesia that also create novel synesthetic experiences, but at a high rate—sometimes creating novel experiences every few seconds. We argue that one-shot synesthesias indicate that synesthetic associations are by their nature not prewired at birth but are dynamically constructed through mental operations and according to the needs of a synesthetic mind. Our conclusions have implications for understanding the biological underpinnings of synesthesia and the role the phenomenon plays in the lives of people endowed with synesthetic capacities.

  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. Optimization of Laser Beam Transformation Hardening by One Single Parameter

    NARCIS (Netherlands)

    Meijer, J.; van Sprang, I.

    1991-01-01

    The process of laser beam transformation hardening is principally controlled by two independent parameters, the absorbed laser power on a given area and the interaction time. These parameters can be transformed into two functional parameters: the maximum surface temperature and the hardening depth.

  10. LOPUT Laser: A novel concept to realize single longitudinal mode ...

    Indian Academy of Sciences (India)

    2014-02-05

    Feb 5, 2014 ... Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India. ∗ ... terpropagating waves inside the gain medium to suppress the effect of SHB in the laser cavity [4–6]. ... propagating linearly polarized modes add up to result in a travelling wave along the gain medium ...

  11. Single-shot echo-planar imaging with Nyquist ghost compensation: interleaved dual echo with acceleration (IDEA) echo-planar imaging (EPI).

    Science.gov (United States)

    Poser, Benedikt A; Barth, Markus; Goa, Pål-Erik; Deng, Weiran; Stenger, V Andrew

    2013-01-01

    Echo planar imaging (EPI) is most commonly used for blood oxygen level-dependent fMRI, owing to its sensitivity and acquisition speed. A major problem with EPI is Nyquist (N/2) ghosting, most notably at high field. EPI data are acquired under an oscillating readout gradient and hence vulnerable to gradient imperfections such as eddy current delays and off-resonance effects, as these cause inconsistencies between odd and even k-space lines after time reversal. We propose a straightforward and pragmatic method herein termed "interleaved dual echo with acceleration (IDEA) EPI": two k-spaces (echoes) are acquired under the positive and negative readout lobes, respectively, by performing phase encoding blips only before alternate readout gradients. From these two k-spaces, two almost entirely ghost free images per shot can be constructed, without need for phase correction. The doubled echo train length can be compensated by parallel imaging and/or partial Fourier acquisition. The two k-spaces can either be complex averaged during reconstruction, which results in near-perfect cancellation of residual phase errors, or reconstructed into separate images. We demonstrate the efficacy of IDEA EPI and show phantom and in vivo images at both 3 T and 7 T. Copyright © 2012 Wiley Periodicals, Inc.

  12. Single-mode quantum cascade lasers employing a candy-cane shaped monolithic coupled cavity

    Science.gov (United States)

    Liu, Peter Q.; Sladek, Kamil; Wang, Xiaojun; Fan, Jen-Yu; Gmachl, Claire F.

    2011-12-01

    We demonstrate single-mode quantum cascade lasers emitting at ˜4.5 μm by employing a monolithic "candy-cane" shaped coupled-cavity consisting of a straight section connecting at one end to a spiral section. The fabrication process is identical to those for simple Fabry-Perot-type ridge lasers. Continuously tunable single-mode emission across ˜8 cm-1 with side mode suppression ratio up to ˜25 dB and a single-mode operating current range of more than 70% above the threshold current is achieved when the lasers are operated in pulsed-mode from 80 K to 155 K.

  13. Design optimization of single-main-amplifier KrF laser-fusion systems

    International Nuclear Information System (INIS)

    Harris, D.B.; Pendergrass, J.H.

    1985-01-01

    KrF lasers appear to be a very promising laser fusion driver for commercial applications. The Large Amplifier Module for the Aurora Laser System at Los Alamos is the largest KrF laser in the world and is currently operating at 5 kJ with 10 to 15 kJ eventually expected. The next generation system is anticipated to be a single-main-amplifier system that generates approximately 100 kJ. This paper examines the cost and efficiency tradeoffs for a complete single-main-amplifier KrF laser fusion experimental facility. It has been found that a 7% efficient $310/joule complete laser-fusion system is possible by using large amplifier modules and high optical fluences

  14. Highly optimized tunable Er3+-doped single longitudinal mode fiber ring laser, experiment and model

    DEFF Research Database (Denmark)

    Poulsen, Christian; Sejka, Milan

    1993-01-01

    A continuous wave (CW) tunable diode-pumped Er3+-doped fiber ring laser, pumped by diode laser at wavelengths around 1480 nm, is discussed. Wavelength tuning range of 42 nm, maximum slope efficiency of 48% and output power of 14.4 mW have been achieved. Single longitudinal mode lasing with a line...... with a linewidth of 6 kHz has been measured. A fast model of erbium-doped fiber laser was developed and used to optimize output parameters of the laser......A continuous wave (CW) tunable diode-pumped Er3+-doped fiber ring laser, pumped by diode laser at wavelengths around 1480 nm, is discussed. Wavelength tuning range of 42 nm, maximum slope efficiency of 48% and output power of 14.4 mW have been achieved. Single longitudinal mode lasing...

  15. Experimental Performance of a Single-Mode Ytterbium-doped Fiber Ring Laser with Intracavity Modulator

    Science.gov (United States)

    Numata, Kenji; Camp, Jordan

    2012-01-01

    We have developed a linearly polarized Ytterbium-doped fiber ring laser with a single longitudinal mode output at 1064 run. A fiber-coupled intracavity phase modulator ensured mode-hop free operation and allowed fast frequency tuning. The fiber laser was locked with high stability to an iodine-stabilized laser, showing a frequency noise suppression of a factor approx 10 (exp 5) at 1 mHz

  16. Wavelength-selectable and steady single-mode erbium-doped fiber multiple ring laser

    Science.gov (United States)

    Yeh, Chien-Hung; Yang, Zi-Qing; Huang, Tzu-Jung; Chow, Chi-Wai; Chen, Jing-Heng; Chen, Kun-Huang

    2017-11-01

    To achieve a stable and selectable C-band erbium-doped fiber (EDF) laser with single-longitudinal-mode output, a multiple ring architecture is proposed and demonstrated experimentally. In this work, we design a passively quadruple-ring structure in the cavity of an EDF laser to produce a Vernier effect with a mode filter for suppressing the multimode spikes significantly. In addition, the output performance and stability of the proposed EDF ring laser are discussed.

  17. Semiconductor laser engineering, reliability and diagnostics a practical approach to high power and single mode devices

    CERN Document Server

    Epperlein, Peter W

    2013-01-01

    This reference book provides a fully integrated novel approach to the development of high-power, single-transverse mode, edge-emitting diode lasers by addressing the complementary topics of device engineering, reliability engineering and device diagnostics in the same book, and thus closes the gap in the current book literature. Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performa...

  18. Continuous-wave singly resonant optical parametric oscillator placed inside a ring laser.

    Science.gov (United States)

    Abitan, Haim; Buchhave, Preben

    2003-11-20

    A cw singly resonant optical parametric oscillator (SRO) was built and placed inside the cavity of a ring laser. The system consists of a diode-end-pumped Nd:YVO4 ring laser with intracavity periodically poled lithium niobate as the nonlinear gain medium of the SRO. When the laser was operated in a unidirectional mode, we obtained more than 520 mW of signal power in one beam. When the laser was operated in a bidirectional mode, we obtained 600 mW of signal power (300 mW in two separate beams). The power and the spectral features of the laser in the unidirectional and bidirectional modes were measured while the laser was coupled with the SRO. The results show that it is preferable to couple a SRO with a unidirectional ring laser.

  19. Continuous-wave singly resonant optical parametric oscillator placed inside a ring laser

    DEFF Research Database (Denmark)

    Abitan, Haim; Buchhave, Preben

    2003-01-01

    in a unidirectional mode, we obtained more than 520 mW of signal power in one beam. When the laser was operated in a bidirectional mode, we obtained 600 mW of signal power (300 mW in two separate beams). The power and the spectral features of the laser in the unidirectional and bidirectional modes were measured while......A cw singly resonant optical parametric oscillator (SRO) was built and placed inside the cavity of a ring laser. The system consists of a diode-end-pumped Nd:YVO4 ring laser with intracavity periodically poled lithium niobate as the nonlinear gain medium of the SRO. When the laser was operated...... the laser was coupled with the SRO. The results show that it is preferable to couple a SRO with a unidirectional ring laser....

  20. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

    Science.gov (United States)

    Varshnay, N. K.; Singh, A.; Benerji, N. S.

    2017-02-01

    Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C-C energy transfer circuit and thyratron is used as a high-voltage main switch with single-stage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni-Zn ferrite cores. The laser can generate about 150 mJ at ˜100 Hz rep-rate reliably from a discharge volume of 100 cm 3. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

  1. Operational characteristics of dual gain single cavity Nd:YVO 4 laser

    Indian Academy of Sciences (India)

    Operational characteristics of a dual gain single cavity Nd:YVO4 laser have been investigated. With semiconductor diode laser pump power of 2 W, 800 mW output was obtained with a slope efficiency of 49%. Further, by changing the relative orientation of the two crystals the polarization characteristics of the output could be ...

  2. Insensitivity of single particle time domain measurements to laser velocimeter 'Doppler ambiguity.'

    Science.gov (United States)

    Johnson, D. A.

    1973-01-01

    It is shown that single particle time domain measurements in high speed gas flows obtained by a laser velocimeter technique developed for use in wind tunnels are not affected by the so-called 'Doppler ambiguity.' A comparison of hot-wire anemometer and laser velocimeter measurements taken under similar flow conditions is used for the demonstration.

  3. Analytical Expression for the Electric Field of the Single Mode Laser ...

    African Journals Online (AJOL)

    The simplest model of the laser is that of a single mode system homogenously broadened. The dynamical behavior of this laser is described by three differential equations, called Haken-Lorenz equations[1], similar to the Lorenz model [1] already known to predict deterministic chaos. In previous recent work [5-7] we have ...

  4. Performance characteristics of an excimer laser (XeCl) with single ...

    Indian Academy of Sciences (India)

    2017-01-10

    Jan 10, 2017 ... Abstract. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compres- sion suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for ...

  5. Laser-induced down-conversion parameters of singly and doubly ...

    Indian Academy of Sciences (India)

    Singly and doubly doped ZnS phosphors have been synthesized using flux method. Laser-induced photoluminescence has been observed in ZnS-doped phosphors when these were excited by the pulsed UV N2 laser radiation. Due to down-conversion phenomenon, fast phosphorescence emission in the visible region is ...

  6. Performance characteristics of an excimer laser (XeCl) with single ...

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/pram/088/02/0033. Keywords. XeCl excimer laser; magnetic pulse compressor; saturable inductor; micro-machining. Abstract. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented ...

  7. Passive Fe2+ : ZnSe single-crystal Q switch for 3-mu m lasers

    NARCIS (Netherlands)

    Voronov, AA; Kozlovskii, [No Value; Korostelin, YV; Podmar'kov, YP; Polushkin, VG; Frolov, MP

    Passive Q-switching of 3-mu m lasers with the help of a Fe2+ : ZnSe single crystal is demonstrated. The 6-mJ, 50-ns giant pulses are obtained from a 2.9364-mu m Er : YAG laser by using this passive Q switch.

  8. Quantum cascade laser infrared spectroscopy of single cancer cells

    KAUST Repository

    Patel, Imran

    2017-03-27

    Quantum cascade laser infrared spectroscopy is a next generation novel imaging technique allowing high resolution spectral imaging of cells. We show after spectral pre-processing, identification of different cancer cell populations within minutes.

  9. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  10. High Energy Single Frequency Fiber Laser at Low Repetition Rate, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  11. Tunable Single Frequency 1.55 Micron Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a widely tunable, narrow linewidth, single frequency fiber laser by developing an innovative Er/Yb-co-doped...

  12. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  13. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  14. High Energy Single Frequency Fiber Laser at Low Repetition Rate, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system operating at low repetition rate of 10 Hz to 1 kHz for coherent Lidar systems...

  15. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  16. Single slit interference made easy with a strand of hair and a laser

    Science.gov (United States)

    Messer, Rebecca

    2018-01-01

    Students can easily measure the width of a strand of their own hair with a monochromatic light source such as a laser. This inexpensive activity engages students in an application of single slit diffraction using Babinet's principle.

  17. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  18. Two-color monochromatic x-ray imaging with a single short-pulse laser

    Science.gov (United States)

    Sawada, H.; Daykin, T.; McLean, H. S.; Chen, H.; Patel, P. K.; Ping, Y.; Pérez, F.

    2017-06-01

    Simultaneous monochromatic crystal imaging at 4.5 and 8.0 keV with x-rays produced by a single short-pulse laser is presented. A layered target consisting of thin foils of titanium and copper glued together is irradiated by the 50 TW Leopard short-pulse laser housed at the Nevada Terawatt Facility. Laser-accelerated MeV fast electrons transmitting through the target induce Kα fluorescence from both foils. Two energy-selective curved crystals in the imaging diagnostic form separate monochromatic images on a single imaging detector. The experiment demonstrates simultaneous two-color monochromatic imaging of the foils on a single detector as well as Kα x-ray production at two different photon energies with a single laser beam. Application of the diagnostic technique to x-ray radiography of a high density plasma is also presented.

  19. Single Frequency Lasers for Space-Based Wind and Aerosol Lidar, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR will develop single frequency cw laser technology for 2um lidar and UV interferometer locking control critical to NASA missions that will measure...

  20. Frequency-Locked Single-Frequency Fiber Laser at 2 Micron, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Frequency-locked single-frequency 2 micron fiber laser is proposed to be used for airborne/spaceborne coherent lidar measurements, i.e., Active Sensing of CO2...

  1. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  2. High Power Compact Single-Frequency Volume Bragg Er-Doped Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this NASA SBIR Phase I proposal is to develop the prototype of a compact single-frequency mode one longitudinal and one transverse mode laser...

  3. Gravitational Wave Detection with Single-Laser Atom Interferometers

    Science.gov (United States)

    Yu, Nan; Tinto, Massimo

    2011-01-01

    A new design for a broadband detector of gravitational radiation relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser are used for operating the two atom interferometers. The innovation here involves the fact that the atoms in the atom interferometers are not only considered as perfect test masses, but also as highly stable clocks. Atomic coherence is intrinsically stable, and can be many orders of magnitude more stable than a laser.

  4. Single Longitudinal Mode, High Repetition Rate, Q-switched Ho:YLF Laser for Remote Sensing

    Science.gov (United States)

    Bai, Yingxin; Yu, Jirong; Petzar, Paul; Petros, M.; Chen, Songsheng; Trieu, Bo; Lee, Nyung; Singh, U.

    2009-01-01

    Ho:YLF/LuLiF lasers have specific applications for remote sensing such as wind-speed measurement and carbon dioxide (CO2) concentration measurement in the atmosphere because the operating wavelength (around 2 m) is located in the eye-safe range and can be tuned to the characteristic lines of CO2 absorption and there is strong backward scattering signal from aerosol (Mie scattering). Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of with a repetition rate of 5 Hz and pulse energy of 75 mJ [1]. For highly precise CO2 measurements with coherent detection technique, a laser with high repetition rate is required to averaging out the speckle effect [2]. In addition, laser efficiency is critically important for the air/space borne lidar applications, because of the limited power supply. A diode pumped Ho:Tm:YLF laser is difficult to efficiently operate in high repetition rate due to the large heat loading and up-conversion. However, a Tm:fiber laser pumped Ho:YLF laser with low heat loading can be operated at high repetition rates efficiently [3]. No matter whether wind-speed or carbon dioxide (CO2) concentration measurement is the goal, a Ho:YLF/LuLiF laser as the transmitter should operate in a single longitudinal mode. Injection seeding is a valid technique for a Q-switched laser to obtain single longitudinal mode operation. In this paper, we will report the new results for a single longitudinal mode, high repetition rate, Q-switched Ho:YLF laser. In order to avoid spectral hole burning and make injection seeding easier, a four mirror ring cavity is designed for single longitudinal mode, high repetition rate Q-switched Ho:YLF laser. The ramp-fire technique is chosen for injection seeding.

  5. Technology and engineering aspects of high power pulsed single longitudinal mode dye lasers

    Science.gov (United States)

    Rawat, V. S.; Mukherjee, Jaya; Gantayet, L. M.

    2015-09-01

    Tunable single mode pulsed dye lasers are capable of generating optical radiations in the visible range having very small bandwidths (transform limited), high average power (a few kW) at a high pulse repetition rate (a few tens of kHz), small beam divergence and relatively higher efficiencies. These dye lasers are generally utilized laser dyes dissolved in solvents such as water, heavy water, ethanol, methanol, etc. to provide a rapidly flowing gain medium. The dye laser is a versatile tool, which can lase either in the continuous wave (CW) or in the pulsed mode with pulse duration as small as a few tens of femtoseconds. In this review, we have examined the several cavity designs, various types of gain mediums and numerous types of dye cell geometries for obtaining the single longitudinal mode pulsed dye laser. Different types of cavity configuration, such as very short cavity, short cavity with frequency selective element and relatively longer cavity with multiple frequency selective elements were reviewed. These single mode lasers have been pumped by all kinds of pumping sources such as flash lamps, Excimer, Nitrogen, Ruby, Nd:YAG, Copper Bromide and Copper Vapor Lasers. The single mode dye lasers are either pumped transversely or longitudinally to the resonator axis. The pulse repletion rate of these pump lasers were ranging from a few Hz to a few tens of kHz. Physics technology and engineering aspects of tuning mechanism, mode hop free scanning and dye cell designs are also presented in this review. Tuning of a single mode dye laser with a resolution of a few MHz per step is a technologically challenging task, which is discussed here.

  6. Utilizing wheel-ring architecture for stable and selectable single-longitudinal-mode erbium fiber laser

    Science.gov (United States)

    Yeh, Chien-Hung; Yang, Zi-Qing; Huang, Tzu-Jung; Chow, Chi-Wai

    2018-03-01

    To achieve a steady single-longitudinal-mode (SLM) erbium-doped fiber (EDF) laser, the wheel-ring architecture is proposed in the laser cavity. According to Vernier effect, the proposed wheel-ring can produce three different free spectrum ranges (FSRs) to serve as the mode-filter for suppressing the densely multi-longitudinal-mode (MLM). Here, to complete wavelength-tunable EDF laser, an optical tunable bandpass filter (OTBF) is utilized inside the cavity for tuning arbitrarily. In addition, the entire output performances of the proposed EDF wheel-ring laser are also discussed and analyzed experimentally.

  7. Single and double long pulse laser ablation of aluminum induced in air and water ambient

    Energy Technology Data Exchange (ETDEWEB)

    Akbari Jafarabadi, Marzieh; Mahdieh, Mohammad Hossein, E-mail: mahdm@iust.ac.ir

    2017-02-28

    Highlights: • Laser ablation of aluminum target by single and double pulse (∼ 5 ns delay) in ambient air and distilled water • Comparing with air, in ambient water, plasma confinement results in higher crater depth. • In comparison with single pulse laser ablation, the absorption of the laser pulse energy is higher for double pulse regime. • As a result of ablated material expansion, the crater depth is decreased if the target is placed at lower depth. - Abstract: In this paper, single pulse and double pulse laser ablation of an aluminum target in two interaction ambient was investigated experimentally. The interaction was performed by nanosecond Nd:YAG laser beam in air and four depths (i.e. 9, 13, 17, and 21 mm) of distilled water ambient. The irradiation was carried out in single and collinear double pulse configurations in both air and liquid ambient. Crater geometry (depth and diameter) was measured by an optical microscope. The results indicated that the crater geometry strongly depends on both single pulse and double pulse configurations and interaction ambient. In single pulse regime, the crater diameter is higher for all water depths compared to that of air. However, the crater depth, depend on water depth, is higher or lower than the crater depth in air. In double pulse laser ablation, there are greater values for both crater diameters and crater depths in the water.

  8. The Physics of Shot Towers

    Science.gov (United States)

    Lipscombe, Trevor C.; Mungan, Carl E.

    2012-01-01

    In the late 18th and throughout the 19th century, lead shot for muskets was prepared by use of a shot tower. Molten lead was poured from the top of a tower and, during its fall, the drops became spherical under the action of surface tension. In this article, we ask and answer the question: "How does the size of the lead shot depend on the height…

  9. Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics

    Directory of Open Access Journals (Sweden)

    Mizuho Fushitani

    2016-11-01

    Full Text Available We present applications of extreme ultraviolet (XUV single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N2 molecules.

  10. Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics.

    Science.gov (United States)

    Fushitani, Mizuho; Hishikawa, Akiyoshi

    2016-11-01

    We present applications of extreme ultraviolet (XUV) single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I 2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N 2 molecules.

  11. Transverse single-mode edge-emitting lasers based on coupled waveguides.

    Science.gov (United States)

    Gordeev, Nikita Yu; Payusov, Alexey S; Shernyakov, Yuri M; Mintairov, Sergey A; Kalyuzhnyy, Nikolay A; Kulagina, Marina M; Maximov, Mikhail V

    2015-05-01

    We report on the transverse single-mode emission from InGaAs/GaAs quantum well edge-emitting lasers with broadened waveguide. The lasers are based on coupled large optical cavity (CLOC) structures where high-order vertical modes of the broad active waveguide are suppressed due to their resonant tunneling into a coupled single-mode passive waveguide. The CLOC lasers have shown stable Gaussian-shaped vertical far-field profiles with a reduced divergence of ∼22° FWHM (full width at half-maximum) in CW (continuous-wave) operation.

  12. Coilable single crystal fibers of doped-YAG for high power laser applications

    Science.gov (United States)

    Maxwell, Gisele; Soleimani, Nazila; Ponting, Bennett; Gebremichael, Eminet

    2013-05-01

    Single crystal fibers are an intermediate between laser crystals and doped glass fibers. They can combine the advantages of both by guiding laser light and matching the efficiencies found in bulk crystals, making them ideal candidates for high-power laser and fiber laser applications. In particular, a very interesting feature of single crystal fiber is that they can generate high power in the eye-safe range (Er:YAG) with a high efficiency, opening new possibilities for portable directed energy weapons. This work focuses on the growth of a flexible fiber with a core of dopant (Er, Nd, Yb, etc…) that will exhibit good waveguiding properties. Direct growth or a combination of growth and cladding experiments are described. We have, to date, demonstrated the growth of a flexible foot long 45 microns doped YAG fiber. Scattering loss measurements at visible wavelengths along with dopant profile characterization are also presented. Laser characterization for these fibers is in progress.

  13. Doppler wind lidar using a MOPA semiconductor laser at stable single-frequency operation

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Pedersen, Christian

    2009-01-01

    A compact master-oscillator power-amplifier semiconductor laser (MOPA-SL) is a good candidate for a coherent light source (operating at 1550 nm) in a Doppler wind Lidar. The MOPA-SL requires two injection currents: Idfb for the distributed-feedback (DFB) laser section (master oscillator) and Iamp...... for the tapered amplifier section. The specified maximum current values are 0.7 A and 4.0 A for Idfb and Iamp. Although the MOPA-SL has been proven capable of producing single-frequency CW output beam, stable operation at this spectral condition has also been known to highly depend on the drive currents...... to the laser. This was done by observing the spectral characteristic of the laser using an optical spectrum at different drive current combinations. When using the laser for a Doppler wind Lidar application, a combination of (Idfb, Iamp) which is close to the center of an identified stable single...

  14. Optically addressable single-use microfluidic valves by laser printer lithography.

    Science.gov (United States)

    Garcia-Cordero, Jose L; Kurzbuch, Dirk; Benito-Lopez, Fernando; Diamond, Dermot; Lee, Luke P; Ricco, Antonio J

    2010-10-21

    We report the design, fabrication, and characterization of practical microfluidic valves fabricated using laser printer lithography. These optofluidic valves are opened by directing optical energy from a solid-state laser, with similar power characteristics to those used in CD/DVD drives, to a spot of printed toner where localized heating melts an orifice in the polymer layer in as little as 500 ms, connecting previously isolated fluidic components or compartments. Valve functionality, response time, and laser input energy dependence of orifice size are reported for cyclo-olefin polymer (COP) and polyethylene terephthalate (PET) films. Implementation of these optofluidic valves is demonstrated on pressure-driven and centrifugal microfluidic platforms. In addition, these "one-shot" valves comprise a continuous polymer film that hermetically isolates on-chip fluid volumes within fluidic devices using low-vapor-permeability materials; we confirmed this for a period of one month. The fabrication and integration of optofluidic valves are compatible with a range of polymer microfabrication technologies and should facilitate the development of fully integrated, reconfigurable, and automated lab-on-a-chip systems, particularly when reagents must be stored on chip for extended periods, e.g. for medical diagnostic devices, lab-on-a-chip synthetic systems, or hazardous biochemical analysis platforms.

  15. Electrically tunable Brillouin fiber laser based on a metal-coated single-mode optical fiber

    Directory of Open Access Journals (Sweden)

    S.M. Popov

    Full Text Available We explore tunability of the Brillouin fiber laser employing Joule heating. For this purpose, 10-m-length of a metal-coated single-mode optical cavity fiber has been directly included into an electrical circuit, like a conductor wire. With the current up to ∼3.5 A the laser tuning is demonstrated over a spectrum range of ∼400 MHz. The observed laser line broadening up to ∼2 MHz is explained by frequency drift and mode-hoping in the laser caused by thermal noise. Keywords: Brillouin fiber laser, Metal-coated optical fiber, Laser tuning, Fiber sensors

  16. Frequency stabilization of multiple lasers on a single medium-finesse cavity

    Science.gov (United States)

    Han, Chengyin; Zhou, Min; Gao, Qi; Li, Shangyan; Zhang, Shuang; Qiao, Hao; Ai, Di; Zhang, Mengya; Lou, Ge; Luo, Limeng; Xu, Xinye

    2018-04-01

    We present a simple, compact, and robust frequency stabilization system of three lasers operating at 649, 759, and 770 nm, respectively. These lasers are applied in experiments on ytterbium optical lattice clocks, for which each laser needs to have a linewidth of a few hundred or tens of kilohertz while maintaining a favorable long-term stability. Here, a single medium-finesse cavity is adopted as the frequency reference and the standard Pound-Drever-Hall technique is used to stabilize the laser frequencies. Based on the independent phase modulation, multiple-laser locking is demonstrated without mutual intervention. The locked lasers are measured to have a linewidth of 100 kHz and the residual frequency drift is about 78.5 Hz s-1. This kind of setup provides a construction that is much simpler than that in previous work.

  17. Shot-to-shot fluctuations in the directed superradiant emission from extended atomic samples

    International Nuclear Information System (INIS)

    Clemens, J P; Horvath, L; Sanders, B C; Carmichael, H J

    2004-01-01

    We study collective spontaneous emission from arbitrary distributions of N two-state atoms using quantum trajectory theory and without an a priori single-mode assumption. Assuming a fully excited initial state, we calculate the angular distribution of the average intensity, focusing on pencil- and disc-shaped samples. The formalism is developed around an unravelling of the master equation in terms of source mode quantum jumps. A modified boson approximation is made to treat the many-atom case, where it is found that strong directional superradiance with shot-to-shot fluctuations occurs for a few hundred to a few thousand atoms

  18. Single frequency Nd:YLF and Nd:YVO4 laser in the red emission

    International Nuclear Information System (INIS)

    Camargo, Fabiola de Almeida

    2010-01-01

    All solid-state continuous-wave (cw) narrow emission linewidth and tunable red lasers are convenient alternative sources to bulky and expensive dye-lasers for high precision laser spectroscopy. Single-frequency operation of diode-pumped Nd:YLiF 4 and Nd:YVO 4 cw ring lasers were investigated in the 1.32 - 1.34μm range, together with their intracavity second-harmonic generation (SHG) to the red spectral range (0.65 - 0.67μm) using either BiB 3 O 6 (BiBO) or periodically-poled KTiOPO 4 (ppKTP) crystals. We report on such a single-end diode-pumped Nd:YVO 4 unidirectional red ring laser containing a type-I cut BiBO nonlinear crystal, yielding a record of 680 mW of single-longitudinal mode (SLM) red output power at 671.1nm without any intra-cavity etalon. For smooth SLM wavelength tuning over the full gain bandwidth (∼4 nm), a partially-coated (R = 40%) 100μm-thin etalon was found necessary, reducing the maximum SLM power (at 671.15 nm) to 380 mW. At 1342.5nm and with a T = 2% transmission output coupler, the laser provided an optimal 1.5W of single-frequency power. We demonstrate also optimal intracavity SHG of a Nd:YLF ring laser in the π- polarization (λ = 1321.5nm) using a ppKTP. The laser yielded 1.4 W of single frequency red power at 660.5 nm, as much as the maximum fundamental power that can be extracted from the resonator using an optimal output coupler. With a partially coated (R = 25%) thin etalon, the laser was tunable over Δλ∼ 1.6nm. (author)

  19. Industrial integration of high coherence tunable single frequency semiconductor lasers based on VECSEL technology for scientific instrumentation in NIR and MIR

    Science.gov (United States)

    Lecocq, Vincent; Chomet, Baptiste; Ferrières, Laurence; Myara, Mikhaël.; Beaudoin, Grégoire; Sagnes, Isabelle; Cerutti, Laurent; Denet, Stéphane; Garnache, Arnaud

    2017-02-01

    Laser technology is finding applications in areas such as high resolution spectroscopy, radar-lidar, velocimetry, or atomic clock where highly coherent tunable high power light sources are required. The Vertical External Cavity Surface Emitting Laser (VECSEL) technology [1] has been identified for years as a good candidate to reach high power, high coherence and broad tunability while covering a wide emission wavelength range exploiting III-V semiconductor technologies. Offering such performances in the Near- and Middle-IR range, GaAs- and Sb-based VECSEL technologies seem to be a well suited path to meet the required specifications of demanding applications. Built up in this field, our expertise allows the realization of compact and low power consumption marketable products, with performances that do not exist on the market today in the 0.8-1.1 μm and 2-2.5 μm spectral range. Here we demonstrate highly coherent broadly tunable single frequency laser micro-chip, intracavity element free, based on a patented VECSEL technology, integrated into a compact module with driving electronics. VECSEL devices emitting in the Near and Middle-IR developed in the frame of this work [2] exhibit exciting features compared to diode-pumped solid-state lasers and DFB diode lasers; they combine high power (>100mW) high temporal coherence together with a low divergence diffraction limited TEM00 beam. They exhibit a class-A dynamics with a Relative Intensity Noise as low as -140dB/Hz and at shot noise level reached above 200MHz RF frequency (up to 160GHz), a free running narrow linewidth at sub MHz level (fundamental limit at Hz level) with high spectral purity (SMSR >55dB), a linear polarization (>50dB suppression ratio), and broadband continuous tunability greater than 400GHz (state of the art commercial technologies thanks to a combination of power-coherence-wavelength tunability performances and integration.

  20. LOPUT Laser: A novel concept to realize single longitudinal mode ...

    Indian Academy of Sciences (India)

    2014-02-05

    TMC). [4–6]. A typical TMC contains two .... LOPUT Laser. Figure 5. M2 measured at 1 W output using propagation method. parameter from the measured spot size variation along the axial direction. Figure 5 shows the typical ...

  1. Opto-injection into single living cells by femtosecond near-infrared laser

    Science.gov (United States)

    Peng, Cheng

    This dissertation presents a novel technique to deliver membrane impermeable molecules into single living cells with the assistance of femtosecond (fs) near-infrared (NIR) laser pulses. This approach merges ultrafast laser technology with key biological, biomedical, and medical applications, such as gene transfection, gene therapy and drug delivery. This technique promises several major advantages, namely, very high transfection efficiency, high cell survival rate (≈100%) and fully preserved cell viabilities. It is also a promising method to deliver molecules into cells that are difficult or even completely resistant to established physical methods, such as microinjection by glass pipettes, electroporation, and biolistics. In this work, the system for fs NIR opto-injection was designed and built. Successful fs NIR opto-injection has been performed on several cell systems including single mammalian cells (bovine aortic endothelial cells), marine animal eggs (Spisula solidissima oocytes), and human cancer cells (fibrosarcoma HT1080) cultured in a tissue-like environment. The connections between laser parameters and cell responses were explored through further experiments and in-depth analyses, especially the relationship between dye uptake rate and incident laser intensity, and the relationship between pore size created on cell membranes and incident laser intensity. Dye uptake rate of the target cells was observed to depend on incident laser intensity. Pore size was found dependent on incident laser intensity. The conclusion was made that laser-induced breakdown and plasma-induced ablation in cell membrane are the physical principles that govern the process of fs NIR opto-injection.

  2. Buster-Jangle Shot Dog

    International Nuclear Information System (INIS)

    Kaul, Dean C.

    1987-01-01

    Shot Dog of the Buster-Jangle Series used a device which had a high-explosive configuration virtually identical to that of the Nagasaki bomb, though with different fissionable components. Dog was detonated at a height of 431.9 m with the mean atmospheric conditions between burst and ground being dry air density 1.027 mg/cc and atmospheric moisture density 0.006 mg/cc. The ground was taken to be that of Nevada test site (NTS) area 9 with a water content of 8% by weight. The yield of the weapon was 21 kt. Results shown here for Buster-Jangle Shot Dog have been scaled from those calculated for Ranger Shot Fox. The design features and burst geometries of the two devices were deemed sufficiently similar to make this substitution in the absence of a radiation leakage spectrum calculated explicitly for Buster-Jangle Shot Dog. However, while the relative atmospheric contents of the two shots were very similar, Shot Fox took place in air of approximately 10% greater density than Shot Dog. Thus, scaled calculated results could not be obtained to compare with the three closest measurement points at Shot Dog

  3. Diode-pumped, single frequency Nd:YLF laser for 60-beam OMEGA laser pulse-shaping system

    International Nuclear Information System (INIS)

    Okishev, A.V.; Seka, W.

    1997-01-01

    The operational conditions of the OMEGA pulse-shaping system require an extremely reliable and low-maintenance master oscillator. The authors have developed a diode-pumped, single-frequency, pulsed Nd:YLF laser for this application. The laser generates Q-switched pulses of ∼160-ns duration and ∼10-microJ energy content at the 1,053-nm wavelength with low amplitude fluctuations (<0.6% rms) and low temporal jitter (<7 ns rms). Amplitude and frequency feedback stabilization systems have been used for high long-term amplitude and frequency stability

  4. Summary Report of Working Group 6: Laser-Plasma Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Leemans, Wim P.; Downer, Michael; Siders, Craig

    2006-07-01

    A summary is given of presentations and discussions in theLaser-Plasma Acceleration Working Group at the 2006 Advanced AcceleratorConcepts Workshop. Presentation highlights include: widespreadobservation of quasi-monoenergetic electrons; good agreement betweenmeasured and simulated beam properties; the first demonstration oflaser-plasma acceleration up to 1 GeV; single-shot visualization of laserwakefield structure; new methods for measuring<100 fs electronbunches; and new methods for "machining" laser-plasma acceleratorstructures. Discussion of future direction includes: developing a roadmapfor laser-plasma acceleration beyond 1 GeV; a debate over injection andguiding; benchmarking simulations with improved wake diagnostics;petawatt laser technology for future laser-plasmaaccelerators.

  5. Single-Particle Time-of-Flight Mass Spectrometry Utilizing a Femtosecond Desorption and Ionization Laser.

    Science.gov (United States)

    Zawadowicz, Maria A; Abdelmonem, Ahmed; Mohr, Claudia; Saathoff, Harald; Froyd, Karl D; Murphy, Daniel M; Leisner, Thomas; Cziczo, Daniel J

    2015-12-15

    Single-particle time-of-flight mass spectrometry has now been used since the 1990s to determine particle-to-particle variability and internal mixing state. Instruments commonly use 193 nm excimer or 266 nm frequency-quadrupled Nd:YAG lasers to ablate and ionize particles in a single step. We describe the use of a femtosecond laser system (800 nm wavelength, 100 fs pulse duration) in combination with an existing single-particle time-of-flight mass spectrometer. The goal of this project was to determine the suitability of a femtosecond laser for single-particle studies via direct comparison to the excimer laser (193 nm wavelength, ∼10 ns pulse duration) usually used with the instrument. Laser power, frequency, and polarization were varied to determine the effect on mass spectra. Atmospherically relevant materials that are often used in laboratory studies, ammonium nitrate and sodium chloride, were used for the aerosol. Detection of trace amounts of a heavy metal, lead, in an ammonium nitrate matrix was also investigated. The femtosecond ionization had a large air background not present with the 193 nm excimer and produced more multiply charged ions. Overall, we find that femtosecond laser ablation and ionization of aerosol particles is not radically different than that provided by a 193 nm excimer.

  6. Surface microstructure and chemistry of polyimide by single pulse ablation of picosecond laser

    Science.gov (United States)

    Du, Qifeng; Chen, Ting; Liu, Jianguo; Zeng, Xiaoyan

    2018-03-01

    Polyimide (PI) surface was ablated by the single pulse of picosecond laser, and the effects of laser wavelength (λ= 355 nm and 1064 nm) and fluence on surface microstructure and chemistry were explored. Scanning electron microscopy (SEM) analysis found that different surface microstructures, i.e., the concave of concentric ring and the convex of porous circular disk, were generated by 355 nm and 1064 nm picosecond laser ablation, respectively. X-ray photoelectron spectroscopy (XPS) characterization indicated that due to the high peak energy density of picosecond laser, oxygen and nitrogen from the ambient were incorporated into the PI surface mainly in the form of Cdbnd O and Csbnd Nsbnd C groups. Thus, both of the O/C and N/C atomic content ratios increased, but the increase caused by 1064 nm wavelength laser was larger. It inferred that the differences of PI surface microstructures and chemistry resulted from different laser parameters were related to different laser-matter interaction effects. For 355 nm picosecond laser, no obvious thermal features were observed and the probable ablation process of PI was mainly governed by photochemical effect; while for 1064 nm picosecond laser, obvious thermal feature appeared and photothermal effect was thought to be dominant.

  7. All-fiber single-mode high modulation rate pseudorandom-coded laser

    Science.gov (United States)

    Zhang, Xin; Yang, Fang; Liu, Yuan; He, Yan; Hou, Xia; Chen, Weibiao

    2013-12-01

    An all-fiber high modulation speed pseudorandom-coded laser based on master oscillator power amplifier configuration is proposed. We use a high modulation rate distributed feedback laser diode as the seed laser to generate the original pseudorandom pulse train. The modulation rate is 1 Gb/s, which corresponds to a minimum pulse interval of 1 ns. A 1 kHz repetition frequency of 10-order M-sequence pseudorandom pulse train is chosen to balance on-line data processing speed and laser ranging resolution. Then, the pseudorandom pulse train is amplified by two-stage amplifiers to boost the output power. All components used in the amplifiers are built in single mode (SM) fiber, so the final output laser is SM with excellent beam quality. Finally, the peak power of pseudorandom code laser is amplified to 23.6 W from 1.5 mW without wave distortion, corresponding to a gain of 42 dB. The ranging experiment of using the optical fiber delay method indoors shows the transmitter of combining modulated laser diode and multistage fiber amplifiers as a promising solution for developing laser for pseudorandom-coded laser ranging.

  8. A pulsed single-frequency Nd:GGG/BaWO4 Raman laser

    Science.gov (United States)

    Liu, Zhaojun; Men, Shaojie; Cong, Zhenhua; Qin, Zengguang; Zhang, Xingyu; Zhang, Huaijin

    2018-04-01

    A single-frequency pulsed laser at 1178.3 nm was demonstrated in a crystalline Raman laser. A crystal combination of Nd:GGG and BaWO4 was selected to realize Raman conversion from a 1062.5 nm fundamental wave to a 1178.3 nm Stokes wave. An entangled cavity was specially designed to form an intracavity Raman configuration. Single-longitudinal-mode operation was realized by introducing two Fabry–Perot etalons into the Raman laser cavity. This laser operated at a pulse repetition rate of 50 Hz with 2 ms long envelopes containing micro pulses at a 30 kHz repetition rate. The highest output power was 41 mW with the micro pulse duration of 15 ns. The linewidth was measured to be less than 130 MHz.

  9. All-normal-dispersion fiber laser with NALM: power scalability of the single-pulse regime

    Science.gov (United States)

    Gao, Gan; Zhang, Haitao; Li, Yuhe; Deng, Decai

    2018-03-01

    We investigate the average power scalability of all-normal-dispersion fiber integrated lasers with a nonlinear amplifying loop. This laser generates 34 ps pulses at a repetition of 8 MHz and spectral width of 30 nm when increased to the highest power. The laser operates on a single-pulse train regime and can be de-chirped as short as 200 fs. The 60 mW output power which can be maintained while operating with low Raman effect is the highest average power achieved for this type of laser in the sub-200 fs regime. The laser becomes unstable due to the strengthening of the Raman–Stokes pulse. Output pulses show great stability in testing.

  10. Optical transmission through a polarization preserving single mode optical fiber at two Ar(+) laser wavelengths

    Science.gov (United States)

    Tedjojuwono, Ken K.; Hunter, William W., Jr.

    1989-01-01

    The transmission characteristics of two Ar(+) laser wavelengths through a twenty meter Panda type Polarization Preserving Single Mode Optical Fiber (PPSMOF) were measured. The measurements were done with both single and multi-longitudinal mode radiation. In the single longitudinal mode case, a degrading Stimulated Brillouin Scattering (SBS) is observed as a backward scattering loss. By choosing an optimum coupling system and manipulating the input polarization, the threshold of the SBS onset can be raised and the transmission efficiency can be increased.

  11. Diode-end-pumped single-longitudinal-mode passively Q-switched Nd:GGG laser

    Science.gov (United States)

    Xue, Feng; Zhang, Sasa; Cong, Zhenhua; Huang, Qingjie; Guan, Chen; Wu, Qianwen; Chen, Hui; Bai, Fen; Liu, Zhaojun

    2018-03-01

    Diode-end-pumped passively Q-switched Nd:GGG laser in a ring cavity at 1062 nm was demonstrated. Single-longitudinal-mode laser linewidth less than 0.5 pm was accomplished by unidirectional operation. The maximum output pulse energy was 437 µJ and the pulse width was 43 ns when Cr4+:YAG with an initial transmission of 61% was used.

  12. Single step high-speed printing of continuous silver lines by laser-induced forward transfer

    Energy Technology Data Exchange (ETDEWEB)

    Puerto, D., E-mail: puerto@lp3.univ-mrs.fr [Aix-Marseille University, CNRS, LP3 laboratory Campus de Luminy, C.917, Marseille (France); Biver, E. [Aix-Marseille University, CNRS, LP3 laboratory Campus de Luminy, C.917, Marseille (France); Oxford Lasers Ltd., Unit 8, Moorbrook Park, Didcot, OX11 7HP (United Kingdom); Alloncle, A.-P.; Delaporte, Ph. [Aix-Marseille University, CNRS, LP3 laboratory Campus de Luminy, C.917, Marseille (France)

    2016-06-30

    Highlights: • We have performed an experimental study on laser micro-printing of silver nanoparticle inks. • We have achieved the printing of lines in a single pass at velocities of 17 m/s (1 MHz laser). • The ejection dynamics has been investigated by means of a time-resolved imaging technique. • The control of the donor film properties is of prime importance to print lines at high velocities. • Continuous conductive lines of silver inks are laser-printed on PET flexible substrates. - Abstract: The development of high-speed ink printing process by Laser-Induced Forward Transfer (LIFT) is of great interest for the printing community. To address the problems and the limitations of this process that have been previously identified, we have performed an experimental study on laser micro-printing of silver nanoparticle inks by LIFT and demonstrated for the first time the printing of continuous conductive lines in a single pass at velocities of 17 m/s using a 1 MHz repetition rate laser. We investigated the printing process by means of a time-resolved imaging technique to visualize the ejection dynamics of single and adjacent jets. The control of the donor film properties is of prime importance to achieve single step printing of continuous lines at high velocities. We use a 30 ps pulse duration laser with a wavelength of 343 nm and a repetition rate from 0.2 to 1 MHz. A galvanometric mirror head controls the distance between two consecutives jets by scanning the focused beam along an ink-coated donor substrate at different velocities. Droplets and lines of silver inks are laser-printed on glass and PET flexible substrates and we characterized their morphological quality by atomic force microscope (AFM) and optical microscope.

  13. Single application on iris localization technology in excimer laser for astigmatism

    OpenAIRE

    Jun-Hua Hao; Yan-Jun Ren; Xia Liu; Jie Guo; Ji Li; Ya-Juan Zhang

    2014-01-01

    AIM:To discuss the single application on iris localization technology in excimer laser for the treatment of astigmatism. METHODS:Totally 203 cases(406 eyes)of laser in situ keratomileusis(LASIK)in the treatment of compound myopic astigmatism patients were operated from November 2011 to November 2012 in our hospital. They were divided into two groups. One was observation group using iris localization and the other was control group using routine operation. Patients in the observation group of ...

  14. Multi-illumination Gabor holography recorded in a single camera snap-shot for high-resolution phase retrieval in digital in-line holographic microscopy

    Science.gov (United States)

    Sanz, Martin; Picazo-Bueno, Jose A.; Garcia, Javier; Micó, Vicente

    2015-05-01

    In this contribution we introduce MISHELF microscopy, a new concept and design of a lensless holographic microscope based on wavelength multiplexing, single hologram acquisition and digital image processing. The technique which name comes from Multi-Illumination Single-Holographic-Exposure Lensless Fresnel microscopy, is based on the simultaneous illumination and recording of three diffraction patterns in the Fresnel domain. In combination with a novel and fast iterative phase retrieval algorithm, MISHELF microscopy is capable of high-resolution (micron range) phase-retrieved (twin image elimination) biological imaging of dynamic events (video rate recording speed) since it avoids the time multiplexing needed for the in-line hologram sequence recording when using conventional phase-shifting or phase retrieval algorithms. MISHELF microscopy is validated using two different experimental layouts: one using RGB illumination and detection schemes and another using IRRB as illumination while keeping the RGB color camera as detection device. Preliminary experimental results are provided for both experimental layouts using a synthetic object (USAF resolution test target).

  15. Graphene based widely-tunable and singly-polarized pulse generation with random fiber lasers

    Science.gov (United States)

    Yao, B. C.; Rao, Y. J.; Wang, Z. N.; Wu, Y.; Zhou, J. H.; Wu, H.; Fan, M. Q.; Cao, X. L.; Zhang, W. L.; Chen, Y. F.; Li, Y. R.; Churkin, D.; Turitsyn, S.; Wong, C. W.

    2015-12-01

    Pulse generation often requires a stabilized cavity and its corresponding mode structure for initial phase-locking. Contrastingly, modeless cavity-free random lasers provide new possibilities for high quantum efficiency lasing that could potentially be widely tunable spectrally and temporally. Pulse generation in random lasers, however, has remained elusive since the discovery of modeless gain lasing. Here we report coherent pulse generation with modeless random lasers based on the unique polarization selectivity and broadband saturable absorption of monolayer graphene. Simultaneous temporal compression of cavity-free pulses are observed with such a polarization modulation, along with a broadly-tunable pulsewidth across two orders of magnitude down to 900 ps, a broadly-tunable repetition rate across three orders of magnitude up to 3 MHz, and a singly-polarized pulse train at 41 dB extinction ratio, about an order of magnitude larger than conventional pulsed fiber lasers. Moreover, our graphene-based pulse formation also demonstrates robust pulse-to-pulse stability and wide-wavelength operation due to the cavity-less feature. Such a graphene-based architecture not only provides a tunable pulsed random laser for fiber-optic sensing, speckle-free imaging, and laser-material processing, but also a new way for the non-random CW fiber lasers to generate widely tunable and singly-polarized pulses.

  16. Reaction-time-resolved measurements of laser-induced fluorescence in a shock tube with a single laser pulse

    Science.gov (United States)

    Zabeti, S.; Fikri, M.; Schulz, C.

    2017-11-01

    Shock tubes allow for the study of ultra-fast gas-phase reactions on the microsecond time scale. Because the repetition rate of the experiments is low, it is crucial to gain as much information as possible from each individual measurement. While reaction-time-resolved species concentration and temperature measurements with fast absorption methods are established, conventional laser-induced fluorescence (LIF) measurements with pulsed lasers provide data only at a single reaction time. Therefore, fluorescence methods have rarely been used in shock-tube diagnostics. In this paper, a novel experimental concept is presented that allows reaction-time-resolved LIF measurements with one single laser pulse using a test section that is equipped with several optical ports. After the passage of the shock wave, the reactive mixture is excited along the center of the tube with a 266-nm laser beam directed through a window in the end wall of the shock tube. The emitted LIF signal is collected through elongated sidewall windows and focused onto the entrance slit of an imaging spectrometer coupled to an intensified CCD camera. The one-dimensional spatial resolution of the measurement translates into a reaction-time-resolved measurement while the species information can be gained from the spectral axis of the detected two-dimensional image. Anisole pyrolysis was selected as the benchmark reaction to demonstrate the new apparatus.

  17. Changes in susceptibility signs on serial T2*-weighted single-shot echo-planar gradient-echo images in acute embolic infarction: comparison with recanalization status on 3D time-of-flight magnetic resonance angiography

    International Nuclear Information System (INIS)

    Shinohara, Yuki; Kinoshita, Toshibumi; Kinoshita, Fumiko

    2012-01-01

    The present study compares changes in susceptibility signs on follow-up single-shot echo-planar gradient-echo T2*-weighted images (GRE-EPI) with vascular status on follow-up magnetic resonance angiography (MRA) in acute embolic infarction. Twenty consecutive patients with acute embolic infarction repeatedly underwent MR imaging including GRE-EPI and MRA using a 1.5-T MR superconducting system. All patients underwent initial MR examination within 24 h of onset and follow-up MR imaging within 1 month after onset. Changes in susceptibility signs on follow-up GRE-EPI were compatible with vascular status on follow-up MRA in 19 of the 20 patients. Susceptibility signs disappeared with complete recanalization in 13 patients, migrated with partial recanalization in 3, did not change together with the absence of recanalization in 2, and became extended together with the absence of recanalization in 1. Cerebral hemorrhage obscured susceptibility signs in the one remaining patient. Susceptibility signs on follow-up GRE-EPI can reflect changes in an acute embolus, such as recanalization or migration, in this study. Serial GRE-EPI in acute embolism complements the diagnostic certainty of MRA by directly detecting an embolus as a susceptibility sign. (orig.)

  18. Shot Noise in Gravitational-Wave Detectors with Fabry-Perot Arms

    OpenAIRE

    Lyons, Torrey T.; Regehr, Martin W.; Raab, Frederick J.

    2000-01-01

    Shot-noise-limited sensitivity is calculated for gravitational-wave interferometers with Fabry–Perot arms, similar to those being installed at the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Italian–French Laser Interferometer Collaboration (VIRGO) facility. This calculation includes the effect of nonstationary shot noise that is due to phase modulation of the light. The resulting formula is experimentally verified by a test interferometer with suspended mirrors in the ...

  19. Shot noise in gravitational-wave detectors with Fabry-Perot arms.

    Science.gov (United States)

    Lyons, T T; Regehr, M W; Raab, F J

    2000-12-20

    Shot-noise-limited sensitivity is calculated for gravitational-wave interferometers with Fabry-Perot arms, similar to those being installed at the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Italian-French Laser Interferometer Collaboration (VIRGO) facility. This calculation includes the effect of nonstationary shot noise that is due to phase modulation of the light. The resulting formula is experimentally verified by a test interferometer with suspended mirrors in the 40-m arms.

  20. Time delay between singly and doubly ionizing wavepackets in laser-driven helium

    International Nuclear Information System (INIS)

    Parker, J S; Doherty, B J S; Meharg, K J; Taylor, K T

    2003-01-01

    We present calculations of the time delay between single and double ionization of helium, obtained from full-dimensionality numerical integrations of the helium-laser Schroedinger equation. The notion of a quantum mechanical time delay is defined in terms of the interval between correlated bursts of single and double ionization. Calculations are performed at 390 and 780 nm in laser intensities that range from 2 x 10 14 to 14 x 10 14 Wcm -2 . We find results consistent with the rescattering model of double ionization but supporting its classical interpretation only at 780 nm. (letter to the editor)

  1. Tree Height Growth Measurement with Single-Scan Airborne, Static Terrestrial and Mobile Laser Scanning

    Directory of Open Access Journals (Sweden)

    Yi Lin

    2012-09-01

    Full Text Available This study explores the feasibility of applying single-scan airborne, static terrestrial and mobile laser scanning for improving the accuracy of tree height growth measurement. Specifically, compared to the traditional works on forest growth inventory with airborne laser scanning, two issues are regarded: “Can the new technique characterize the height growth for each individual tree?” and “Can this technique refine the minimum growth-discernable temporal interval further?” To solve these two puzzles, the sampling principles of the three laser scanning modes were first examined, and their error sources against the task of tree-top capturing were also analyzed. Next, the three-year growths of 58 Nordic maple trees (Crimson King for test were intermittently surveyed with one type of laser scanning each time and then analyzed by statistics. The evaluations show that the height growth of each individual tree still cannot be reliably characterized even by single-scan terrestrial laser scanning, and statistical analysis is necessary in this scenario. After Gaussian regression, it is found that the minimum temporal interval with distinguishable tree height growths can be refined into one month based on terrestrial laser scanning, far better than the two years deduced in the previous works based on airborne laser scanning. The associated mean growth was detected to be about 0.12 m. Moreover, the parameter of tree height generally under-estimated by airborne and even mobile laser scanning can be relatively revised by means of introducing static terrestrial laser scanning data. Overall, the effectiveness of the proposed technique is primarily validated.

  2. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    Energy Technology Data Exchange (ETDEWEB)

    Gribkov, V A; Latyshev, S V [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Miklaszewski, R A; Chernyshova, M [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Drozdowicz, K; Wiacek, U [Institute of Nuclear Physics, Krakow (Poland); Tomaszewski, K [ACS Ltd, Warsaw (Poland); Lemeshko, B D [N L Dukhov All-Russian Institute of Automation, Moscow (Russian Federation)], E-mail: gribkovv@yahoo.com

    2010-03-15

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity ({delta}E/E{approx}1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10{sup 8}-10{sup 9} 2.45 MeV and 10{sup 10}-10{sup 11} 14 MeV neutrons per pulse with pulse duration {approx}10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH{sub 3}OH), phosphoric (H{sub 2}PO{sub 4}) and nitric (HNO{sub 3}) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  3. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    International Nuclear Information System (INIS)

    Gribkov, V A; Latyshev, S V; Miklaszewski, R A; Chernyshova, M; Drozdowicz, K; Wiacek, U; Tomaszewski, K; Lemeshko, B D

    2010-01-01

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E∼1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10 8 -10 9 2.45 MeV and 10 10 -10 11 14 MeV neutrons per pulse with pulse duration ∼10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH 3 OH), phosphoric (H 2 PO 4 ) and nitric (HNO 3 ) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  4. A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

    Science.gov (United States)

    Gribkov, V. A.; Latyshev, S. V.; Miklaszewski, R. A.; Chernyshova, M.; Drozdowicz, K.; Wiącek, U.; Tomaszewski, K.; Lemeshko, B. D.

    2010-03-01

    Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E~1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 108-109 2.45 MeV and 1010-1011 14 MeV neutrons per pulse with pulse duration ~10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation—1 litre bottles with methanol (CH3OH), phosphoric (H2PO4) and nitric (HNO3) acids as well as a long object—a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

  5. Safety and efficacy of high fluence CO2 laser skin resurfacing with a single pass.

    Science.gov (United States)

    Khosh, M M; Larrabee, W F; Smoller, B

    1999-01-01

    Carbon dioxide (CO2) laser skin resurfacing has nearly replaced more traditional methods of superficial skin rejuvenation. Post-treatment erythema is the most common side effect of this method of skin resurfacing. Sublethal thermal damage to the dermis has been proposed as an etiology for post laser erythema. Recent developments in laser resurfacing technology have aimed at minimizing thermal damage to the dermis. To determine depth of skin ablation, extent of thermal injury, and ideal laser parameters for the FeatherTouch laser system. To assess the safety and efficacy of laser resurfacing at high energy fluences with a single pass. Laser resurfacing was performed in the preauricular skin of five patients undergoing rhytidectomy. A total of 60 sites were tested with fluences of 7 to 17 Joules/cm2. Histologic evaluation of excised skin showed maximal thermal injury to be restricted to 60 microns in the papillary dermis. The reticular dermis showed no evidence of injury. Based on these findings, laser resurfacing at 17 J/cm2 (70 watts) was performed on 30 patients (in the periorbital area, a maximum of 9 J/cm2 or 36 watts was used). Follow up ranged between 12 and 18 months. Based on histologic comparison of average and high fluence laser resurfacing, high fluence laser resurfacing did not cause added thermal damage to the reticular dermis. In the clinical group, no major complications such as scarring, scleral show, infection or ectropion were encountered. Transient hyperpigmentation was noted in three patients. Overall patient satisfaction was good to excellent. Post-treatment erythema lasted an average of 4 weeks. We conclude that CO2 laser resurfacing of the face (excluding the periorbital region) can be performed safely and effectively, with the FeatherTouch laser, at 17 J/cm2 with one pass. In our group of patients, laser resurfacing with a single pass at 17 J/cm2 caused less post-operative erythema than two or more passes at 9 J/cm2.

  6. Generalised shot noise Cox processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Torrisi, Giovanni Luca

    We introduce a new class of Cox cluster processes called generalised shot-noise processes (GSNCPs), which extends the definition of shot noise Cox processes (SNCPs) in two directions: the point process which drives the shot noise is not necessarily Poisson, and the kernel of the shot noise can...... be random. Thereby a very large class of models for aggregated or clustered point patterns is obtained. Due to the structure of GSNCPs, a number of useful results can be established. We focus first on deriving summary statistics for GSNCPs and next on how to make simulation for GSNCPs. Particularly, results...... for first and second order moment measures, reduced Palm distributions, the -function, simulation with or without edge effects, and conditional simulation of the intensity function driving a GSNCP are given. Our results are exemplified for special important cases of GSNCPs, and we discuss the relation...

  7. Generalised shot noise Cox processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Torrisi, Giovanni Luca

    2005-01-01

    We introduce a class of cox cluster processes called generalised shot noise Cox processes (GSNCPs), which extends the definition of shot noise Cox processes (SNCPs) in two directions: the point process that drives the shot noise is not necessarily Poisson, and the kernel of the shot noise can...... be random. Thereby, a very large class of models for aggregated or clustered point patterns is obtained. Due to the structure of GSNCPs, a number of useful results can be established. We focus first on deriving summary statistics for GSNCPs and, second, on how to simulate such processes. In particular......, results on first- and second-order moment measures, reduced Palm distributions, the J-function, simulation with or without edge effects, and conditional simulation of the intensity function driving a GSNCP are given. Our results are exemplified in important special cases of GSNCPs, and we discuss...

  8. Single-frequency blue light generation by single-pass sum-frequency generation in a coupled ring cavity tapered laser

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    A generic approach for generation of tunable single frequency light is presented. 340 mW of near diffraction limited, single-frequency, and tunable blue light around 459 nm is generated by sum-frequency generation (SFG) between two tunable tapered diode lasers. One diode laser is operated in a ring...... cavity and another tapered diode laser is single-passed through a nonlinear crystal which is contained in the coupled ring cavity. Using this method, the single-pass conversion efficiency is more than 25%. In contrast to SFG in an external cavity, the system is entirely self-stabilized with no electronic...

  9. Experimental results on recent applications of shot peening

    International Nuclear Information System (INIS)

    Zaid, A.I.O.

    2001-01-01

    Shot peening is a mechanical surface treatment by which the surface of an elastic plastic component is subjected to multiple impact of high speed hard spheres, hence introducing a compressive stress layer of certain depth below the surface. This compressive stress layer results in enhancement of the fatigue life of the component. In this paper, the mechanism of shot peening and the effect of the parameters related to it are reviewed and discussed. The effect of shot peening on the fatigue life of aluminum alloy 7075-T6 and the phenomenological aspects associated with it are also given and discussed. Also, the effect of shot peening on aluminum alloy 2024-T3 in the as received and peened conditions is presented and discussed. Butt single U and butt double vee joints were both investigated from which it was found that the butt single U joint possessed higher values of fatigue life than the double vee joint for the same shot peening intensity. Finally, experimental results on a recent application that is the effect of shot peening on the fatigue life of stainless steel 17-4PH prior to hard chromium plating are given and discussed. Comparison is also made among these results and those obtained in the case of the chromium plated without peening and as received conditions. It was found that shot peening caused an increase of 667% in the fatigue life of stainless steel 17-4PH at 0.57 Y stress level, whereas hard chromium plating was found to reduce its fatigue life and strength. Hence, chromium plating after shot peening is recommended. (author)

  10. Submicrometre periodic surface structures in InP induced by nanosecond UV laser pulses

    International Nuclear Information System (INIS)

    Kumar, Brijesh; Soni, R K

    2008-01-01

    We report fabrication of submicrometre size laser-induced periodic surface structures (ripples) on single crystalline InP by nanosecond (ns) pulsed Nd : YAG laser beam irradiation of fourth harmonic wavelength (266 nm) in HF electrolyte. The ripples are orientated parallel to the laser polarization direction and power spectral density analysis reveals reduction in the spatial period of the ripples with increasing number of laser shots. The formation of periodic structures in the presence of electrolyte is empirically explained on the basis of photoelectrochemical etching and variation of periodicity with refractive index change on laser energy and number of laser pulses. From the analysis of energy dispersive x-ray, photoluminescence (PL) and micro-Raman spectroscopy measurements on the rippled surface we conclude that the ripple structures are capped with a thin layer of In 2 O 3 . Further, a blue shift of 0.328 eV compared with the band-edge luminescence of InP is estimated from the PL spectrum of the structure fabricated with 200 laser shots. The blue shift of the PL peak is attributed to the quantum confinement effect in the nanometre size structures in the rippled surface. Micro-Raman spectra show good crystalline quality of the surface at lower number of laser shots and its degradation caused by oxidation at the higher number of shots

  11. Shot peening of aluminium alloys

    International Nuclear Information System (INIS)

    Le Guernic, Y.

    1998-01-01

    Shot peening is a process of cold-hammering where a metallic surface is pelted with spherical grains. Each grain bumping into the surface acts as a hammer head and creates a small crater. The overlapping of these craters produces a residual compression layer just underneath the surface. It is well known that cracks cannot spread in a compression zone. In most cases of fatigue rupture and stress corrosion cracks propagate from the surface towards the inside so shot peening allows a longer lifetime of castings. Moreover most materials present a better resistance due to the cold-hammering effect of shot peening. Metallic surfaces can be treated in workshops or directly on site. Typical pieces that undergo shot peening on site are storing tanks, gas and steam turbines, tubes of steam generators and piping in oil or nuclear or chemical industries. This article describes shot peening from a theoretical and general point of view and presents the application to aluminium-lithium alloys. In the case of aluminium alloys shot peening can be used to shape the piece (peen-forming). (A.C.)

  12. Surface durability of powder-forged roller treated by shot peening

    International Nuclear Information System (INIS)

    Seki, Masanori; Fujii, Masahiro; Kobayashi, Yuji; Sato, Masaaki; Yoshida, Akira

    2010-01-01

    To investigate the influence of shot peening on the surface durability of powder-forged rollers, the case-hardened powder-forged rollers with a forging density of 7.5 g/cm 3 treated by the single shot peening and the double shot peening were fatigue-tested under a slidingrolling contact condition. The surface roughness, the surface hardness and the surface compressive residual stress of the rollers were increased by the shot peening. In addition, the pores near the roller surface were deformed by the shot peening. The failure mode of all the test rollers was spalling due to subsurface cracking. The fatigue lives of all the test rollers were improved by the shot peening, and that of the test roller S08, which was shot-peened with the hardest steel shots in this experimental range, was especially improved. The surface durability of the test roller S08 was also most improved by the shot peening. Cracks became difficult to occur and propagate under the roller surface since the pores near the roller surface were deformed by the stronger shot peening. In this study, double shot peening, which generally restrains the increase in surface roughness, was not particularly effective for the improvement in the surface durability of the powder-forged rollers, because the influence of tangential force on fatigue was not always great in a case of subsurface cracking

  13. Single cell detection using a glass-based optofluidic device fabricated by femtosecond laser pulses.

    Science.gov (United States)

    Kim, Moosung; Hwang, David J; Jeon, Hojeong; Hiromatsu, Kuniaki; Grigoropoulos, Costas P

    2009-01-21

    We demonstrate the fabrication of integrated three-dimensional microchannel and optical waveguide structures inside fused silica for the interrogation and processing of single cells. The microchannels are fabricated by scanning femtosecond laser pulses (523 nm) and subsequent selective wet etching process. Optical waveguides are additionally integrated with the fabricated microchannels by scanning the laser pulse train inside the glass specimen. Single red blood cells (RBC) in diluted human blood inside of the manufactured microchannel were detected by two optical schemes. The first involved sensing the intensity change of waveguide-delivered He-Ne laser light (632.8 nm) induced by the refractive index difference of a cell flowing in the channel. The other approach was via detection of fluorescence emission from dyed RBC excited by Ar laser light (488 nm) delivered by the optical waveguide. The proposed device was tested to detect 23 fluorescent particles per second by increasing the flow rate up to 0.5 microl min(-1). The optical cell detection experiments support potential implementation of a new generation of glass-based optofluidic biochip devices in various single cell treatment processes including laser based cell processing and sensing.

  14. A diode laser stabilization scheme for 40Ca+ single-ion spectroscopy

    Science.gov (United States)

    Rohde, F.; Almendros, M.; Schuck, C.; Huwer, J.; Hennrich, M.; Eschner, J.

    2010-06-01

    We present a scheme for stabilizing multiple lasers at wavelengths between 795 and 866 nm to the same atomic reference line. A reference laser at 852 nm is stabilized to the Cs D2 line using a Doppler-free frequency modulation technique. Through transfer cavities, four lasers are stabilized to the relevant atomic transitions in 40Ca+. The rms linewidth of a transfer-locked laser is measured to be 123 kHz over 200 ms with respect to an independent atomic reference, the Rb D1 line. This stability is confirmed by the comparison of an excitation spectrum of a single 40Ca+ ion to an eight-level Bloch equation model. The long-term stability with respect to the same reference is measured to be 130 kHz over a period of 2 h. The high degree of stability is demonstrated by the measured Allan deviation around 10-11 between 1 and 100 s.

  15. A diode laser stabilization scheme for 40Ca+ single-ion spectroscopy

    International Nuclear Information System (INIS)

    Rohde, F; Almendros, M; Schuck, C; Huwer, J; Hennrich, M; Eschner, J

    2010-01-01

    We present a scheme for stabilizing multiple lasers at wavelengths between 795 and 866 nm to the same atomic reference line. A reference laser at 852 nm is stabilized to the Cs D 2 line using a Doppler-free frequency modulation technique. Through transfer cavities, four lasers are stabilized to the relevant atomic transitions in 40 Ca + . The rms linewidth of a transfer-locked laser is measured to be 123 kHz over 200 ms with respect to an independent atomic reference, the Rb D 1 line. This stability is confirmed by the comparison of an excitation spectrum of a single 40 Ca + ion to an eight-level Bloch equation model. The long-term stability with respect to the same reference is measured to be 130 kHz over a period of 2 h. The high degree of stability is demonstrated by the measured Allan deviation around 10 -11 between 1 and 100 s.

  16. Ion temperature measurement of a tokamak plasma by collective Thomson scattering of D2O laser radiation

    International Nuclear Information System (INIS)

    Behn, R.; Salito, S.A.; Siegrist, M.R.; Dicken, D.; Hackmann, J.

    1988-10-01

    A D 2 O FIR laser emitting 0.5 J in 1.4 μs at 385 μm and a heterodyne receiver system comprising a Schottky barrier diode mixer with a noise temperature of 8000 K (DSB) were used in a Thomson scattering experiment to measure the ion temperature of a tokamak plasma during a single laser shot. Series of measurements under reproducible plasma conditions have been carried out in H, D and He-plasmas. Their statistical analysis yielded a typical relative error of 25 % for a single shot measurement. (author) 9 figs., 2 tabs., 7 refs

  17. Mode coupling in hybrid square-rectangular lasers for single mode operation

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiu-Wen; Huang, Yong-Zhen, E-mail: yzhuang@semi.ac.cn; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100083 (China)

    2016-08-15

    Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.

  18. Laser spectroscopic investigation of singly and doubly charged thorium ions

    Energy Technology Data Exchange (ETDEWEB)

    Thielking, Johannes; Meier, David-Marcel; Glowacki, Przemyslaw; Okhapkin, Maksim V.; Peik, Ekkehard [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2017-07-01

    The {sup 229}Th isotope possesses a unique, low-energy nuclear isomeric state at about 7.8(5) eV. This fact has stimulated the development of novel ideas in the borderland between atomic and nuclear physics, for example the use as an optical nuclear clock. Since the required precise information on the isomer energy is not yet available, it is intensely searched for using different experimental approaches. For the excitation of the nuclear isomer via electronic bridge or NEET processes, we plan to use two-photon laser excitation of high-lying electronic levels in Th{sup +}. We recently expanded our search range to higher energies and measured 38 previously unknown energy levels in the range from 7.8 eV to 8.7 eV. We also prepare to study the nuclear structure of the isomeric state in cooperation with the Maier-Leibnitz-Laboratorium at LMU Munich, using trapped recoil ions, where the isomeric state is populated via α-decay from {sup 233}U. For this purpose we investigate the hyperfine structure of suitable transitions of Th{sup 2+}.

  19. Stability of the single-mode output of a laser diode array with phase conjugate feedback

    DEFF Research Database (Denmark)

    Juul Jensen, S.; Løbel, M.; Petersen, P.M.

    2000-01-01

    . The output power and the center wavelength are found to be extremely stable in a 100 h stability measurement. External feedback of the output beam into the laser is seen to decrease both the spatial and the temporal coherence of the output significantly. We outline an approach to obtain a stable single......The stability of the output of a single-mode laser diode array with frequency selective phase conjugate feedback has been investigated experimentally. Both the long-term stability of the laser output and the sensitivity to feedback generated by external reflection of the output beam are examined......-mode output when external feedback is present using spatial filtering in the path of the output beam. (C) 2000 American Institute of Physics....

  20. Fiber-laser-pumped continuous-wave singly resonant optical parametric oscillator

    NARCIS (Netherlands)

    Gross, P.; Klein, M.E.; Walde, T.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.

    2002-01-01

    We report on what is to our knowledge the first continuous-wave (cw) optical parametric oscillator (OPO) that is pumped by a tunable fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled LiNbO3 crystal in a four-mirror ring cavity. At a pump

  1. Raman study on single-walled carbon nanotubes with different laser ...

    Indian Academy of Sciences (India)

    TECS

    identify the nature of carbon nanotubes in a bundle. In this study, we have used the Raman spectroscopic analysis on vertically aligned single-walled carbon nanotubes (SWCNTs) grown by the chemical vapour depo- sition (CVD) technique. The grown sample is excited with two laser excitation wavelengths, 633 nm from ...

  2. Laser microprobe for the study of noble gases and nitrogen in single ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 112; Issue 1. Laser microprobe for the study of noble gases and nitrogen in single grains: A case study of individual chondrules from the Dhajala meteorite. R R Mahajan S V S Murty. Volume 112 Issue 1 March 2003 pp 113-127 ...

  3. GaSb-based single-mode distributed feedback lasers for sensing (Conference Presentation)

    Science.gov (United States)

    Gupta, James A.; Bezinger, Andrew; Lapointe, Jean; Poitras, Daniel; Aers, Geof C.

    2017-02-01

    GaSb-based tunable single-mode diode lasers can enable rapid, highly-selective and highly-sensitive absorption spectroscopy systems for gas sensing. In this work, single-mode distributed feedback (DFB) laser diodes were developed for the detection of various trace gases in the 2-3.3um range, including CO2, CO, HF, H2S, H2O and CH4. The lasers were fabricated using an index-coupled grating process without epitaxial regrowth, making the process significantly less expensive than conventional DFB fabrication. The devices are based on InGaAsSb/AlGaAsSb separate confinement heterostructures grown on GaSb by molecular beam epitaxy. DFB lasers were produced using a two step etch process. Narrow ridge waveguides were first defined by optical lithography and etched into the semiconductor. Lateral gratings were then defined on both sides of the ridge using electron-beam lithography and etched to produce the index-grating. Effective index modeling was used to optimize the ridge width, etch depths and the grating pitch to ensure single-lateral-mode operation and adequate coupling strength. The effective index method was further used to simulate the DFB laser emission spectrum, based on a transfer matrix model for light transmission through the periodic structure. The fabricated lasers exhibit single-mode operation which is tunable through the absorption features of the various target gases by adjustment of the drive current. In addition to the established open-path sensing applications, these devices have great potential for optoelectronic integrated gas sensors, making use of integrated photodetectors and possibly on-chip Si photonics waveguide structures.

  4. High-power green light generation by second harmonic generation of single-frequency tapered diode lasers

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Andersen, Peter E.; Sumpf, Bernd

    2010-01-01

    laser emits in excess of 9 W single-frequency output power with a good beam quality. The output from the tapered diode laser is frequency doubled using periodically poled MgO:LiNbO3. We investigate the modulation potential of the green light and improve the modulation depth from 1:4 to 1:50.......We demonstrate the generation of high power (>1.5W) and single-frequency green light by single-pass second harmonic generation of a high power tapered diode laser. The tapered diode laser consists of a DBR grating for wavelength selectivity, a ridge section and a tapered section. The DBR tapered...

  5. Efficient 525 nm laser generation in single or double resonant cavity

    Science.gov (United States)

    Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

    2018-03-01

    This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

  6. Single-Shot Echo-Planar Diffusion-Weighted MR Imaging at 3T and 1.5T for Differentiation of Benign Vertebral Fracture Edema and Tumor Infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hee Jin; Lee, So Yeon; Rho, Myung Ho; Chung, Eun Chul; Kim, Mi Sung; Kwon, Heon Ju; Youn, In Young [Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 03181 (Korea, Republic of)

    2016-11-01

    To compare the apparent diffusion coefficient (ADC) value using single-shot echo-planar imaging sequences at 3T and 1.5T for differentiation of benign fracture edema and tumor infiltration of the vertebral body. A total of 46 spinal examinations were included in the 1.5T MRI group, and a total of 40 spinal examinations were included in the 3T MRI group. The ADC values of the lesion were measured and calculated. The diagnostic performance of the conventional MR image containing sagittal T2-weighted fat saturated image and each diffusion weighted image (DWI) with an ADC value with different b values were evaluated. The mean ADC value of the benign lesions was higher than that of the malignant lesions on 1.5T and 3T (p < 0.05). The sensitivity of the diagnostic performance was higher with an additional DWI in both 1.5T and 3T, but the sensitivities were similar with the addition of b values of 400 and 1000. The specificities of the diagnostic performances did not show significant differences (p value > 0.05). The diagnostic accuracies were higher when either of the DWIs (b values of 400 and 1000) was added to routine MR image for 1.5T and 3T. Statistical differences between 1.5T and 3T or between b values of 400 and 1000 were not seen. The ADC values of the benign lesions were significantly higher than those of the malignant lesions on 1.5T and 3T. There was no statistically significant difference in the diagnostic performances when either of the DWIs (b values of 400 and 1000) was added to the routine MR image for 1.5T and 3T.

  7. Laser induced breakdown spectroscopy based on single beam splitting and geometric configuration for effective signal enhancement.

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-05

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS.

  8. Fractional Carbon Dioxide Laser for Keratosis Pilaris: A Single-Blind, Randomized, Comparative Study

    Directory of Open Access Journals (Sweden)

    Vasanop Vachiramon

    2016-01-01

    Full Text Available Objective. Keratosis pilaris (KP is a common condition which can frequently be cosmetically disturbing. Topical treatments can be used with limited efficacy. The objective of this study is to evaluate the effectiveness and safety of fractional carbon dioxide (CO2 laser for the treatment of KP. Patients and Methods. A prospective, randomized, single-blinded, intraindividual comparative study was conducted on adult patients with KP. A single session of fractional CO2 laser was performed to one side of arm whereas the contralateral side served as control. Patients were scheduled for follow-up at 4 and 12 weeks after treatment. Clinical improvement was graded subjectively by blinded dermatologists. Patients rated treatment satisfaction at the end of the study. Results. Twenty patients completed the study. All patients stated that the laser treatment improved KP lesions. At 12-week follow-up, 30% of lesions on the laser-treated side had moderate to good improvement according to physicians’ global assessment (p=0.02. Keratotic papules and hyperpigmentation appeared to respond better than the erythematous component. Four patients with Fitzpatrick skin type V developed transient pigmentary alteration. Conclusions. Fractional CO2 laser treatment may be offered to patients with KP. Dark-skinned patients should be treated with special caution.

  9. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS. PMID:25557721

  10. Growth and development of Arabidopsis thaliana under single-wavelength red and blue laser light.

    Science.gov (United States)

    Ooi, Amanda; Wong, Aloysius; Ng, Tien Khee; Marondedze, Claudius; Gehring, Christoph; Ooi, Boon S

    2016-09-23

    Indoor horticulture offers a sensible solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available horticultural lighting is suboptimal, and therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. They are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Furthermore, laser beams can be tailored to match the absorption profiles of different plant species. We have developed a prototype laser growth chamber and demonstrate that plants grown under laser illumination can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs reported previously. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteome data show that the single-wavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture.

  11. Growth and development of Arabidopsis thaliana under single-wavelength red and blue laser light

    KAUST Repository

    Ooi, Amanda Siok Lee

    2016-09-23

    Indoor horticulture offers a sensible solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available horticultural lighting is suboptimal, and therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. They are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Furthermore, laser beams can be tailored to match the absorption profiles of different plant species. We have developed a prototype laser growth chamber and demonstrate that plants grown under laser illumination can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs reported previously. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteome data show that the single-wavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture.

  12. In vivo micro-lesion of single dendrite with femtosecond laser pulses

    Science.gov (United States)

    Sacconi, L.; Masi, A.; Diana, G.; Buffelli, M.; Pavone, F. S.

    2007-07-01

    Recently, two-photon microscopy has been used for high spatial resolution imaging of the intact neocortex in living rodents. In this work we used near-IR femtosecond laser pulses for a combination of two-photon microscopy and microdissection on fluorescently-labeled neuronal structures in living mice. Three-dimensional reconstructions of dendrites expressing the green fluorescence protein were made in the cortex of GFP-M and YFP-H transgenic mice. Afterwards, single dendrites were laser-dissected irradiating the structure with a high femtosecond laser energy dose. We report that laser dissection can be performed with micrometric precision and without any visible collateral damage of the surrounding neuronal structures. After laser irradiation, one part of the severed dendrite underwent degeneration and disappeared within 5 hours. Using a chronically implanted glass window, we performed long-term imaging in the area of the dissected dendrite. Images of the long-term morphological changes in the neuronal network after dendritic lesioning will be provided. Laser microdissection of selected structures of the neuronal branching in vivo represents a promising tool for neurobiological research.

  13. High energy, single frequency, tunable laser source operating in burst mode for space based lidar applications

    Science.gov (United States)

    Cosentino, Alberto; Mondello, Alessia; Sapia, Adalberto; D'Ottavi, Alessandro; Brotini, Mauro; Gironi, Gianna; Suetta, Enrico

    2017-11-01

    This paper describes energetic, spatial, temporal and spectral characterization measurements of the Engineering Qualification Model (EQM) of the Laser Transmitter Assembly (TXA) used in the ALADIN instrument currently under development for the ESA ADM-AEOLUS mission (EADS Astrium as prime contractor for the satellite and the instrument). The EQM is equivalent to the Flight Model, with the exception of some engineering grade components. The Laser Transmitter Assembly, based on a diode pumped tripled Nd:YAG laser, is used to generate laser pulses at a nominal wavelength of 355 nm. This laser is operated in burst mode, with a pulse repetition cycle of 100 Hz during bursts. It is capable to operate in Single Longitudinal Mode and to be tuned over 25 GHz range. An internal "network" of sensors has been implemented inside the laser architecture to allow "in flight" monitoring of transmitter. Energy in excess of 100 mJ, with a spatial beam quality factor (M2) lower than 3, a spectral linewidth less than 50 MHz with a frequency stability better than 4 MHz on short term period have been measured on the EQM. Most of the obtained results are well within the expected values and match the Instrument requirements. They constitute an important achievement, showing the absence of major critical areas in terms of performance and the capability to obtain them in a rugged and compact structure suitable for space applications. The EQM will be submitted in the near future to an Environmental test campaign.

  14. Demonstration of the synchrotron-type spectrum of laser-produced Betatron radiation

    International Nuclear Information System (INIS)

    Fourmaux, S; Leguay, P M; Payeur, S; Lassonde, P; Gnedyuk, S; Lebrun, G; Kieffer, J C; Corde, S; Ta Phuoc, K; Malka, V; Sebban, S; Rousse, A; Fourment, C

    2011-01-01

    Betatron x-ray radiation in laser-plasma accelerators is produced when electrons are accelerated and wiggled in the laser-wakefield cavity. This femtosecond source, producing intense x-ray beams in the multi-kiloelectronvolt (keV) range, has been observed at different interaction regimes using a high-power laser from 10 to 100 TW. However, none of the spectral measurements carried out were at sufficient resolution, bandwidth and signal-to-noise ratio to precisely determine the shape of spectra with a single laser shot in order to avoid shot-to-shot fluctuations. In this paper, the Betatron radiation produced using a 80 TW laser is characterized by using a single photon counting method. We measure in a single shot spectra from 8 to 21 keV with a resolution better than 350 eV. The results obtained are in excellent agreement with theoretical predictions and demonstrate the synchrotron-type nature of this radiation mechanism. The critical energy is found to be E c =5.6±1 keV for our experimental conditions. In addition, the features of the source at this energy range open up novel opportunities for applications in time-resolved x-ray science.

  15. Lasers As Particle Accelerators In Medicine: From Laser-Driven Protons To Imaging With Thomson Sources

    Science.gov (United States)

    Pogorelsky, I. V.; Babzien, M.; Polyanskiy, M. N.; Yakimenko, V.; Dover, N. P.; Palmer, C. A. J.; Najmudin, Z.; Shkolnikov, P.; Williams, O.; Rosenzweig, J.; Oliva, P.; Carpinelli, M.; Golosio, B.; Delogu, P.; Stefanini, A.; Endrizzi, M.

    2011-06-01

    We report our recent progress using a high-power, picosecond CO2 laser for Thomson scattering and ion acceleration experiments. These experiments capitalize on certain advantages of long-wavelength CO2 lasers, such as their high number of photons per energy unit and beneficial wavelength- scaling of the electrons' ponderomotive energy and critical plasma frequency. High X-ray fluxes produced in the interactions of the counter-propagating laser- and electron-beams for obtaining single-shot, high-contrast images of biological objects. The laser, focused on a hydrogen jet, generated a monoenergetic proton beam via the radiation-pressure mechanism. The energy of protons produced by this method scales linearly with the laser's intensity. We present a plan for scaling the process into the range of 100-MeV proton energy via upgrading the CO2 laser. This development will enable an advance to the laser-driven proton cancer therapy.

  16. High energy nanosecond laser pulses delivered single-mode through hollow-core PBG fibers.

    Science.gov (United States)

    Shephard, Jonathan; Jones, J; Hand, D; Bouwmans, G; Knight, J; Russell, P; Mangan, B

    2004-02-23

    We report on the development of hollow-core photonic bandgap fibers for the delivery of high energy pulses for precision micromachining applications. Short pulses of (65ns pulse width) and energies of the order of 0.37mJ have been delivered in a single spatial mode through hollow-core photonic bandgap fibers at 1064nm using a high repetition rate (15kHz) Nd:YAG laser. The ultimate laser-induced damage threshold and practical limitations of current hollow-core fibers for the delivery of short optical pulses are discussed.

  17. High frequency modulation capabilities and quasi single-sideband emission from a quantum cascade laser.

    Science.gov (United States)

    Hangauer, Andreas; Spinner, Georg; Nikodem, Michal; Wysocki, Gerard

    2014-09-22

    Both intensity- (IM) and frequency-modulation (FM) behavior of a directly modulated quantum cascade laser (QCL) are measured from 300 Hz to 1.7 GHz. Quantitative measurements of tuning coefficients has been performed and the transition from thermal- to electronic-tuning is clearly observed. A very specific FM behavior of QCLs has been identified which allows for optical quasi single sideband (SSB) modulation through current injection and has not been observed in directly modulated semiconductor lasers before. This predestines QCLs in applications where SSB is required, such as telecommunication or high speed spectroscopy. The experimental procedure and theoretical modeling for data extraction is discussed.

  18. The free-electron laser - Maxwell's equations driven by single-particle currents

    Science.gov (United States)

    Colson, W. B.; Ride, S. K.

    1980-01-01

    It is shown that if single particle currents are coupled to Maxwell's equations, the resulting set of self-consistent nonlinear equations describes the evolution of the electron beam and the amplitude and phase of the free-electron-laser field. The formulation is based on the slowly varying amplitude and phase approximation, and the distinction between microscopic and macroscopic scales, which distinguishes the microscopic bunching from the macroscopic pulse propagation. The capabilities of this new theoretical approach become apparent when its predictions for the ultrashort pulse free-electron laser are compared to experimental data; the optical pulse evolution, determined simply and accurately, agrees well with observations.

  19. Linearly frequency-modulated pulsed single-frequency fiber laser at 1083 nm.

    Science.gov (United States)

    Zhang, Yuanfei; Yang, Changsheng; Li, Can; Feng, Zhouming; Xu, Shanhui; Deng, Huaqiu; Yang, Zhongmin

    2016-02-22

    A linearly frequency-modulated, actively Q-switched, single-frequency ring fiber laser based on injection seeding from an ultra-short cavity is demonstrated at 1083 nm. A piezoelectric transducer is employed to obtain linearly frequency-modulating performance and over 1.05 GHz frequency-tuning range is achieved with a modulating frequency reaching tens of kilohertz. A maximum peak power of the stable output pulse is over 3.83 W during frequency-modulating process. This type of pulsed fiber laser provides a promising candidate for coherent LIDAR in the measurement of thermosphere.

  20. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Science.gov (United States)

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  1. Experimental study on the single event effects in pulse width modulators by laser testing

    International Nuclear Information System (INIS)

    Zhao Wen; Guo Xiaoqiang; Chen Wei; Guo Hongxia; Lin Dongsheng; Luo Yinhong; Ding Lili; Wang Yuanming; Wang Hanning

    2015-01-01

    This paper presents single event effect (SEE) characteristics of UC1845AJ pulse width modulators (PWMs) by laser testing. In combination with analysis to map PWM circuitry in the microchip dies, the typical SEE response waveforms for laser pulses located in different circuit blocks of UC1845AJ are obtained and the SEE mechanisms are analyzed. The laser SEE test results show that there are some differences in the SEE mechanisms of different circuit blocks, and phase shifts or changes in the duty cycles of few output pulses are the main SEE behaviors for UC1845AJ. In addition, a new SEE behavior which manifests as changes in the duty cycles of many output pulses is revealed. This means that an SEE hardened design should be considered. (paper)

  2. Analysis of laser-generated plasma ionizing radiation by synthetic single crystal diamond detectors

    Czech Academy of Sciences Publication Activity Database

    Marinelli, M.; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Cutroneo, M.; Torrisi, L.; Margarone, Daniele; Velyhan, Andriy; Krása, Josef; Krouský, Eduard

    2013-01-01

    Roč. 272, May (2013), s. 104-108 ISSN 0169-4332 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE2.3.20.0279; GA MŠk EE.2.3.20.0087; GA MŠk(CZ) 7E09092; GA MŠk(CZ) LC528 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OPVK 3 Laser Zdroj(XE) CZ.1.07/2.3.00/20.0279; OP VK 2 LaserGen(XE) CZ.1.07/2.3.00/20.0087; 7FP LASERLAB-EUROPE(XE) 228334 Program:EE; FP7 Institutional support: RVO:68378271 Keywords : single crystal diamond * diamond detector * laser-generated plasma * ionizing radiation * time-of-fight spectrometer Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.538, year: 2013

  3. Crystal growth, spectral and laser properties of Nd:LSAT single crystal

    Science.gov (United States)

    Hu, P. C.; Yin, J. G.; Zhao, C. C.; Gong, J.; He, X. M.; Zhang, L. H.; Liang, X. Y.; Hang, Y.

    2011-10-01

    Nd:(La, Sr)(Al, Ta)O3 (Nd:LSAT) crystal was grown by the Czochralski method. The absorption and fluorescence spectra of Nd:LSAT crystal at room temperature were investigated. With a fiber-coupled diode laser as pump source, the continuous-wave (CW) laser action of Nd:LSAT crystal was demonstrated. The result of diode-pumped laser operation of Nd:LSAT crystal single crystal is reported for what is to our knowledge the first time. The maximum output power at 1064 nm was obtained to be 165 mW under the incident pump power of 3 W, with the slope efficiency 10.9%.

  4. Stable Single-Mode Operation of Distributed Feedback Quantum Cascade Laser by Optimized Reflectivity Facet Coatings.

    Science.gov (United States)

    Wang, Dong-Bo; Zhang, Jin-Chuan; Cheng, Feng-Min; Zhao, Yue; Zhuo, Ning; Zhai, Shen-Qiang; Wang, Li-Jun; Liu, Jun-Qi; Liu, Shu-Man; Liu, Feng-Qi; Wang, Zhan-Guo

    2018-02-02

    In this work, quantum cascade lasers (QCLs) based on strain compensation combined with two-phonon resonance design are presented. Distributed feedback (DFB) laser emitting at ~ 4.76 μm was fabricated through a standard buried first-order grating and buried heterostructure (BH) processing. Stable single-mode emission is achieved under all injection currents and temperature conditions without any mode hop by the optimized antireflection (AR) coating on the front facet. The AR coating consists of a double layer dielectric of Al 2 O 3 and Ge. For a 2-mm laser cavity, the maximum output power of the AR-coated DFB-QCL was more than 170 mW at 20 °C with a high wall-plug efficiency (WPE) of 4.7% in a continuous-wave (CW) mode.

  5. Selective mode coupling in microring resonators for single mode semiconductor lasers

    Science.gov (United States)

    Arbabi, Amir

    Single mode semiconductor laser diodes have many applications in optical communications, metrology and sensing. Edge-emitting single mode lasers commonly use distributed feedback structures, or narrowband reflectors such as distributed Bragg reflectors (DBRs) and sampled grating distributed Bragg reflectors (SGDBRs). Compact, narrowband reflectors with high reflectivities are of interest to replace the commonly used DBRs and SGDBRs. This thesis presents our work on the simulation, design, fabrication, and characterization of devices operating based on the coupling of degenerate modes of a microring resonator, and investigation of the possibility of using them for improving the performance of laser diodes. In particular, we demonstrate a new type of compact, narrowband, on-chip reflector realized by selectively coupling degenerate modes of a microring resonator. For the simulation and design of reflective microring resonators, a fast and accurate analysis method is required. Conventional numerical methods for solving Maxwell's equations such as the finite difference time domain and the finite element method (FEM) provide accurate results but are computationally intense and are not suitable for the design of large 3D structures. We formulated a set of coupled mode equations that, combined with 2D FEM simulations, can provide a fast and accurate tool for the modeling and design of reflective microrings. We developed fabrication processing recipes and fabricated passive reflective microrings on silicon substrates with a silicon nitride core and silicon dioxide cladding. Narrowband single wavelength reflectors were realized which are 70 times smaller than a conventional DBR with the same bandwidth. Compared to the conventional DBR, they have faster roll-off, and no side modes. The smaller footprint saves real estate, reduces tuning power and makes these devices attractive as in-line mirrors for low threshold narrow linewidth laser diodes. Self-heating caused by material

  6. Peculiarities of single track formation from TI6AL4V alloy at different laser power densities by selective laser melting

    Directory of Open Access Journals (Sweden)

    Yadroitsava, I.

    2015-11-01

    Full Text Available This paper describes the geometrical characteristics of single tracks manufactured by selective laser melting (SLM at different laser powers (20-170 W and scanning speeds (0.1-2.0 m/s. Simulation of temperature distribution during processing is carried out. A conclusion about the optimal process parameters and peculiarities of selective laser melting of Ti6Al4V alloy at low and high laser powers and scanning speeds is reached. The analysis of temperature fields creates opportunities to build parts with the desired properties by using SLM.

  7. Cost-effective design of a concurrent photoacoustic-ultrasound microscope using single laser pulses

    Science.gov (United States)

    Wu, Wen-Shao; Liu, Wei-Wen; Li, Pai-Chi

    2016-03-01

    A method for concurrent photoacoustic (PA) and ultrasound (US) imaging with single laser pulses was previously demonstrated. An optical-absorbing multilayer film that can generate a US pulse based on the thermoelastic effect is used. With such a film, the generated US can be adjusted so that it does not overlap with the spectrum of the PA signal generated by the light transmitting through the layer. Thus, the US signal and the PA signal can be generated and separated by using a single laser pulse with spectral filtering. In this study, we continue with the same concurrent imaging approach and propose a cost-effective and portable design. The design consists of a pulsed laser diode with the repetition rate up to 25 kHz and energy of 2 μJ/pulse. A multilayer film is employed to generate narrow band US signals under laser excitation for US imaging. With simple spectral filtering, the PA signals and the US signals can be separated. With optical resolution, the system has a theoretical lateral resolution of 2 μm in PA imaging and 200 μm in US imaging. One of the applications of the proposed microscope is for tumor biology, where angiogenesis is an essential topic for understanding tumor growth and tumor metastasis. We will demonstrate performance of the proposed system by imaging vasculature networks.

  8. Nonpolar InGaN/GaN Core-Shell Single Nanowire Lasers.

    Science.gov (United States)

    Li, Changyi; Wright, Jeremy B; Liu, Sheng; Lu, Ping; Figiel, Jeffrey J; Leung, Benjamin; Chow, Weng W; Brener, Igal; Koleske, Daniel D; Luk, Ting-Shan; Feezell, Daniel F; Brueck, S R J; Wang, George T

    2017-02-08

    We report lasing from nonpolar p-i-n InGaN/GaN multi-quantum well core-shell single-nanowire lasers by optical pumping at room temperature. The nanowire lasers were fabricated using a hybrid approach consisting of a top-down two-step etch process followed by a bottom-up regrowth process, enabling precise geometrical control and high material gain and optical confinement. The modal gain spectra and the gain curves of the core-shell nanowire lasers were measured using micro-photoluminescence and analyzed using the Hakki-Paoli method. Significantly lower lasing thresholds due to high optical gain were measured compared to previously reported semipolar InGaN/GaN core-shell nanowires, despite significantly shorter cavity lengths and reduced active region volume. Mode simulations show that due to the core-shell architecture, annular-shaped modes have higher optical confinement than solid transverse modes. The results show the viability of this p-i-n nonpolar core-shell nanowire architecture, previously investigated for next-generation light-emitting diodes, as low-threshold, coherent UV-visible nanoscale light emitters, and open a route toward monolithic, integrable, electrically injected single-nanowire lasers operating at room temperature.

  9. Resonant ablation of single-wall carbon nanotubes by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Arutyunyan, N R; Komlenok, M S; Kononenko, V V; Pashinin, V P; Pozharov, A S; Konov, V I; Obraztsova, E D

    2015-01-01

    The thin 50 nm film of bundled arc-discharge single-wall carbon nanotubes was irradiated by femtosecond laser pulses with wavelengths 675, 1350 and 1745 nm corresponding to the absorption band of metallic nanotubes E 11 M , to the background absorption and to the absorption band of semiconducting nanotubes E 11 S , respectively. The aim was to induce a selective removal of nanotubes of specific type from the bundled material. Similar to conducted thermal heating experiments, the effect of laser irradiation results in suppression of all radial breathing modes in the Raman spectra, with preferential destruction of the metallic nanotubes with diameters less than 1.26 nm and of the semiconducting nanotubes with diameters 1.36 nm. However, the etching rate of different nanotubes depends on the wavelength of the laser irradiation. It is demonstrated that the relative content of nanotubes of different chiralities can be tuned by a resonant laser ablation of undesired nanotube fraction. The preferential etching of the resonant nanotubes has been shown for laser wavelengths 675 nm (E 11 M ) and 1745 nm (E 11 S ). (paper)

  10. Single- and multi-wavelength laser operation of a diode-pumped ND:GGG single crystal around 1.33 μm

    Science.gov (United States)

    Xu, Bin; Wang, Yi; Cheng, Yongjie; Xu, Huiying; Cai, Zhiping; Moncorgé, Richard

    2015-06-01

    We report on the first continuous-wave laser operation of a diode-pumped Nd:GGG single crystal at several emission wavelengths in the 1.33 μm spectral domain. Multi-wavelength laser operation at 1324, 1331 and 1337 nm with a maximum laser output power of 1.83 W and a laser slope efficiency of 28.9% for an output coupler transmission of 2.2% is obtained in the free-running regime. By inserting and tilting a 0.1-mm BK7 glass etalon to modulate the losses inside the laser cavity, single wavelength lasing at 1324 nm and 1347 nm are also achieved with maximum output powers of about 0.77 W and 0.41 W as well as laser slope efficiencies of 15.2% and 12.6%, respectively. Further increasing the pump power, based on the position of the etalon leading to the single laser wavelength operation at 1347 nm, stable dual-wavelength laser operation is demonstrated at 1337 and 1347 nm with a maximum output power of 0.61 W.

  11. High temperature laser diode based on a single sheet of quantum dots

    Science.gov (United States)

    Ledentsov, N. N.; Shchukin, V. A.; Maximov, M. V.; Shernyakov, Yu M.; Payusov, A. S.; Gordeev, N. Yu; Rouvimov, S. S.

    2015-10-01

    A single sheet of high-density InGaAs quantum dots (QDs) is used as a gain medium of InGaAs-GaAs-AlGaAs lasers. The devices operate at high power in the continuous mode beyond 160 °C with an emission wavelength up to ˜1.27 μm. At short cavity lengths a strong broadening (>300 nm) of the electroluminescence spectrum is observed at high current densities, permitting light sources for broadly wavelength tuneable and multi-wavelength infrared lasers based on a single gain chip, and related frequency conversion devices for the whole visible spectrum range. High power cw operation (>2 W) limited by catastrophic optical mirror damage is realized.

  12. Optical trap for both transparent and absorbing particles in air using a single shaped laser beam.

    Science.gov (United States)

    Redding, Brandon; Pan, Yong-Le

    2015-06-15

    Optical trapping of airborne particles is emerging as an essential tool in applications ranging from online characterization of living cells and aerosols to particle transport and delivery. However, existing optical trapping techniques using a single laser beam can trap only transparent particles (via the radiative pressure force) or absorbing particles (via the photophoretic force), but not particles of either type-limiting the utility of trapping-enabled aerosol characterization techniques. Here, we present the first optical trapping technique capable of trapping both transparent and absorbing particles with arbitrary morphology using a single shaped laser beam. Such a general-purpose optical trapping mechanism could enable new applications such as trapping-enabled aerosol characterization with high specificity.

  13. Single-frequency TEA CO2 laser with a bleaching spectral intracavity filter

    Science.gov (United States)

    Sorochenko, V. R.

    2017-02-01

    The regime of single-frequency operation is realised in a TEA CO2 laser with a spectral filter inside the cavity (a cell filled with SF6) on P(12)-P(24) lines of the 10P band. The minimal scatter of the peak powers of the laser pulses in a series of ‘shots’ and the maximal ratio of the output energies in the single-frequency and free running regimes (greater than 0.84) are obtained on the P(16) line at an optimal SF6 pressure in the cell. Experimental results qualitatively agree with the absorption spectrum of SF6 calculated from the SPECTRA information-analytical system. It is shown that the high ratio of energies in two regimes is achived due to gas bleaching in the cell.

  14. Hydrogen storage in single-wall carbon nano-tubes by means of laser excitation

    International Nuclear Information System (INIS)

    Oksengorn, B.

    2010-01-01

    A new mode for hydrogen adsorption and storage in single-wall carbon nano-tubes is used, on the basis of laser excitation. Remember that this method has been useful to obtain, in the case of the fullerene C 60 , many complex C 60 -atoms or C 60 -molecules, where atoms or molecular particles are trapped inside the C 60 -molecules. We think this method might be important to store many hydrogen molecules inside carbon nano-tubes. (author)

  15. Readout-segmented echo-planar imaging improves the image quality of diffusion-weighted MR imaging in rectal cancer: Comparison with single-shot echo-planar diffusion-weighted sequences

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Chun-chao; Liu, Xi; Peng, Wan-lin; Li, Lei; Zhang, Jin-ge [Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Meng, Wen-jian; Deng, Xiang-bing [Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Zuo, Pan-li [Siemens Healthcare, MR Collaborations NE Asia, 100010, Beijing (China); Li, Zhen-lin, E-mail: lzlcd01@126.com [Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2016-10-15

    Purpose: To determine whether readout-segmented echo-planar imaging (rs-EPI) diffusion-weighted imaging (DWI) can improve the image quality in patients with rectal cancer compared with single-shot echo-planar imaging (ss-EPI) DWI using 3.0 T magnetic resonance (MR) imaging. Materials and methods: This study was approved by the Institutional Review Board, and informed consent was obtained from all patients. Seventy-one patients with rectal cancer were enrolled in this study. For all patients, both rs-EPI and ss-EPI DWI were performed using a 3T MR scanner. Two radiologists independently assessed the overall image quality, lesion conspicuity, geometric distortion and distinction of anatomical structures. The signal-to-noise ratio (SNR), lesion contrast, contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) were also measured. Comparisons of the quantitative and qualitative parameters between the two sequences were performed using the paired t-test and the Wilcoxon signed rank test. Results: The scores of overall image quality, lesion conspicuity, geometric distortion and distinction of anatomical structures of rs-EPI were all significantly higher than those of ss-EPI (all p < 0.05). The SNR and CNR were higher in rs-EPI than those in ss-EPI (all p < 0.05). There was no significant difference between ss-EPI and rs-EPI with regard to ROI size and mean ADCs of the tumour (p = 0.574 and p = 0.479, respectively), but the mean ADC of the normal tissue was higher in rs-EPI than in ss-EPI (1.73 ± 0.30 × 10{sup −3} mm{sup 2}/s vs. 1.60 ± 0.31 × 10{sup −3} mm{sup 2}/s, p = 0.001). Conclusions: DW imaging based on readout-segmented echo-planar imaging is a clinically useful technique to improve the image quality for the purpose of evaluating lesions in patients with rectal tumours.

  16. Single-longitudinal-mode Er:GGG microchip laser operating at 2.7  μm.

    Science.gov (United States)

    You, Zhenyu; Wang, Yan; Xu, Jinlong; Zhu, Zhaojie; Li, Jianfu; Wang, Hongyan; Tu, Chaoyang

    2015-08-15

    We reported on a diode-end-pumped single-longitudinal-mode microchip laser using a 600-μm-thick Er:GGG crystal at ∼2.7  μm, generating a maximum output power of 50.8 mW and the maximum pulsed energy of 0.306 mJ, with repetition rates of pumping light of 300, 200, and 100 Hz, respectively. The maximum slope efficiency of the laser was 20.1%. The laser was operated in a single-longitudinal mode centered at about 2704 nm with a FWHM of 0.42 nm. The laser had a fundamental beam profile and the beam quality parameter M(2) was measured as 1.46. These results indicate that the Er:GGG microchip laser is a potential compact mid-infrared laser source.

  17. Hydrodynamic lift for single cell manipulation in a femtosecond laser fabricated optofluidic chip

    Directory of Open Access Journals (Sweden)

    Bragheri Francesca

    2017-08-01

    Full Text Available Single cell sorting based either on fluorescence or on mechanical properties has been exploited in the last years in microfluidic devices. Hydrodynamic focusing allows increasing the efficiency of theses devices by improving the matching between the region of optical analysis and that of cell flow. Here we present a very simple solution fabricated by femtosecond laser micromachining that exploits flow laminarity in microfluidic channels to easily lift the sample flowing position to the channel portion illuminated by the optical waveguides used for single cell trapping and analysis.

  18. Catastrophic optical mirror damage in diode lasers monitored during single-pulse operation

    DEFF Research Database (Denmark)

    Zegler, M.; Tomm, J.W.; Reeber, D.

    2009-01-01

    Catastrophic optical mirror damage (COMD) is analyzed for 808 nm emitting diode lasers in single-pulse operation in order to separate facet degradation from subsequent degradation processes. During each pulse, nearfield and thermal images are monitored. A temporal resolution better than 7 µs...... is achieved. The thermal runaway process is unambiguously related to the occurrence of a “thermal flash.” A one-by-one correlation between nearfield, thermal flash, thermal runaway, and structural damage is observed. The single-pulse excitation technique allows for controlling the propagation...

  19. A novel hybrid III–V/silicon deformed micro-disk single-mode laser

    International Nuclear Information System (INIS)

    Feng Peng; Zhang Yejin; Liu Lei; Zhang Siriguleng; Wang Hailing; Zheng Wanhua; Wang Yufei

    2015-01-01

    A novel hybrid III–V/silicon deformed micro-disk single-mode laser connecting to a Si output waveguide is designed, and fabricated through BCB bonding technology and standard i-line photolithography. Compared to a traditional circular micro-disk in multi-longitudinal-mode operation, unidirectional emission and single longitudinal-mode output from a Si waveguide are realized. In the experiments, an output power of 0.31 mW and a side-mode suppression ratio of 27 dB in the continuous-wave regime are obtained. (semiconductor devices)

  20. Tunable single-polarization single-longitudinal-mode erbium-doped fiber ring laser employing a CMFBG filter and saturable absorber

    Science.gov (United States)

    Feng, Suchun; Lu, Shaohua; Peng, Wanjing; Li, Qi; Feng, Ting; Jian, Shuisheng

    2013-04-01

    A tunable single-polarization single-longitudinal-mode (SLM) erbium-doped fiber ring laser is proposed and demonstrated. For the first time as we know, a chirped moiré fiber Bragg grating (CMFBG) filter with ultra-narrow transmission band and a uniform fiber Bragg grating (UFBG) are used to select the laser longitudinal mode. The stable SLM operation of the fiber laser is guaranteed by the combination of the CMFBG filter and 3 m unpumped erbium-doped fiber acting as a saturable absorber. The single polarization operation of the fiber laser is obtained by using an inline broadband polarizer. A tuning range of about 0.7 nm with about 0.1 nm step is achieved by stretching the uniform FBG.

  1. Femtosecond laser fabricated microfluorescence-activated cell sorter for single cell recovery

    Science.gov (United States)

    Bragheri, F.; Paiè, P.; Nava, G.; Yang, T.; Minzioni, P.; Martinez Vazquez, R.; Bellini, N.; Ramponi, R.; Cristiani, I.; Osellame, R.

    2014-03-01

    Manipulation, sorting and recovering of specific live cells from samples containing less than a few thousand cells is becoming a major hurdle in rare cell exploration such as stem cell research or cell based diagnostics. Moreover the possibility of recovering single specific cells for culturing and further analysis would be of great impact in many biological fields ranging from regenerative medicine to cancer therapy. In recent years considerable effort has been devoted to the development of integrated and low-cost optofluidic devices able to handle single cells, which usually rely on microfluidic circuits that guarantee a controlled flow of the cells. Among the different microfabrication technologies, femtosecond laser micromachining (FLM) is ideally suited for this purpose as it provides the integration of both microfluidic and optical functions on the same glass chip leading to monolithic, robust and portable devices. Here a new optofluidic device is presented, which is capable of sorting and recovering of single cells, through optical forces, on the basis of their fluorescence and. Both fluorescence detection and single cell sorting functions are integrated in the microfluidic chip by FLM. The device, which is specifically designed to operate with a limited amount of cells but with a very high selectivity, is fabricated by a two-step process that includes femtosecond laser irradiation followed by chemical etching. The capability of the device to act as a micro fluorescence-activated cell sorter has been tested on polystyrene beads and on tumor cells and the results on the single live cell recovery are reported.

  2. An Efficient Single Frequency Ho:YLF Laser for IPDA Lidar Applications

    Science.gov (United States)

    Yu, J.; Bai, Y.; Wong, T.; Reithmeier, K.; Petros, M.

    2016-01-01

    A highly efficient, versatile, single frequency 2-micron pulsed laser can be used in a pulsed Differential Absorption Lidar (DIAL) / Integrated Path Differential Absorption (IPDA) instrument to make precise, high-resolution measurements to investigate sources and sinks of CO2. For a direct detection IPDA lidar, the desired 2 ?m Ho:YLF laser should generate 30-40 mJ pulses at the repetition rate of 100 to 200 Hz, with short pulse length (lidar measurement. The seed beam is entered into the resonator through an output coupler. The laser is mounted on a water cooled optical bench for stable and reliable operation. The size of the optical bench is 22.16 x 9.20 x 1.25 inches. It is stiffened so that the laser can be operated in any orientation of the optical bench. This packaged Ho:YLF laser is designed for either mobile trailer or airborne platform operation. The engineering prototype Ho:YLF laser has been fully characterized to demonstrate laser performance. Figure 1 shows the laser output power as a function of pump power at different pulse repetition rates from 100 Hz to 333 Hz. The threshold of the laser is less than 14 W. The slope efficiencies are 28%, 40%, 41% and 43% for pulse repetition rates of 100, 200, 250 and 333 Hz, respectively. Maximum power increases with the pulse repetition rate. Output power of 4.2 W, 6 W, 6.7 W, and 7.7 W is achieved for pulse repetition rates of 100, 200, 250 and 333Hz, respectively. This represents the optical conversion efficiency of 16.7%, 22.4%, 23.7%, and 26.5% at these various pulse repletion rates. It is the most efficient and compact Ho:YLF laser demonstrated in the high pulse energy (>20mJ) and moderate pulse repetition rate (100's Hz) operation range. As shown in Figure 1, the maximum pulse energy at 100 Hz is 42 mJ. This is limited due to optical damage. The laser stability is characterized and found to be very stable. A relative pulse energy standard deviation of 2% was measured. The beam quality of the Ho:YLF was

  3. Detection and characterization of chemical aerosol using laser-trapping single-particle Raman spectroscopy.

    Science.gov (United States)

    Kalume, Aimable; Beresnev, Leonid A; Santarpia, Joshua; Pan, Yong-Le

    2017-08-10

    Detection and characterization of the presence of chemical agent aerosols in various complex atmospheric environments is an essential defense mission. Raman spectroscopy has the ability to identify chemical molecules, but there are limited numbers of photons detectable from single airborne aerosol particles as they are flowing through a detection system. In this paper, we report on a single-particle Raman spectrometer system that can measure strong spontaneous, stimulated, and resonance Raman spectral peaks from a single laser-trapped chemical aerosol particle, such as a droplet of the VX nerve agent chemical simulant diethyl phthalate. Using this system, time-resolved Raman spectra and elastic scattered intensities were recorded to monitor the chemical properties and size variation of the trapped particle. Such a system supplies a new approach for the detection and characterization of single airborne chemical aerosol particles.

  4. Fabrication and subband gap optical properties of silicon supersaturated with chalcogens by ion implantation and pulsed laser melting

    International Nuclear Information System (INIS)

    Bob, Brion P.; Aziz, Michael J.; Kohno, Atsushi; Charnvanichborikarn, Supakit; Williams, James S.; Warrender, Jeffrey M.; Umezu, Ikurou; Tabbal, Malek

    2010-01-01

    Topographically flat, single crystal silicon supersaturated with the chalcogens S, Se, and Te was prepared by ion implantation followed by pulsed laser melting and rapid solidification. The influences of the number of laser shots on the atomic and carrier concentration-depth profiles were measured with secondary ion mass spectrometry and spreading resistance profiling, respectively. We found good agreement between the atomic concentration-depth profiles obtained from experiments and a one-dimensional model for plane-front melting, solidification, liquid-phase diffusion, with kinetic solute trapping, and surface evaporation. Broadband subband gap absorption is exhibited by all dopants over a wavelength range from 1 to 2.5 microns. The absorption did not change appreciably with increasing number of laser shots, despite a measurable loss of chalcogen and of electronic carriers after each shot.

  5. Assembly procedure for Shot Loading Platform

    International Nuclear Information System (INIS)

    Routh, R.D.

    1995-01-01

    This supporting document describes the assembly procedure for the Shot Loading Platform. The Shot Loading Platform is used by multiple equipment removal projects to load shielding shot in the annular spaces of the equipment storage containers. The platform height is adjustable to accommodate different sizes of storage containers and transport assemblies

  6. 7 CFR 51.904 - Shot berries.

    Science.gov (United States)

    2010-01-01

    ... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.904 Shot berries. Shot berries means very small berries resulting from insufficient pollination, usually seedless in those... 7 Agriculture 2 2010-01-01 2010-01-01 false Shot berries. 51.904 Section 51.904 Agriculture...

  7. 50 CFR 20.134 - Nontoxic shot.

    Science.gov (United States)

    2010-10-01

    ... shot (negative control), or the candidate shot or coated shot. Fluoroscope birds at 1 week after dosage... and 30, collect blood by venipuncture, determine hematocrit, hemoglobin concentration and other.... Provide body weight and blood parameter measurements on samples drawn at 24 hours after dosage and at the...

  8. Intra-shot MSE Calibration Technique For LHCD Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Jinseok; Scott, Steve; Shiraiwa, Syun' ichi; Greenwald, Martin; Parker, Ronald; Wallace, Gregory

    2009-11-23

    The spurious drift in pitch angle of order several degrees measured by the Motional Stark Effect (MSE) diagnostic in the Alcator C-Mod tokamak1 over the course of an experimental run day has precluded direct utilization of independent absolute calibrations. Recently, the underlying cause of the drift has been identified as thermal stress-induced birefringence in a set of in-vessel lenses. The shot-to-shot drift can be avoided by using MSE to measure only the change in pitch angle between a reference phase and a phase of physical interest within a single plasma discharge. This intra-shot calibration technique has been applied to the Lower Hybrid Current Drive (LHCD) experiments and the measured current profiles qualitatively demonstrate several predictions of LHCD theory such as an inverse dependence of current drive efficiency on the parallel refractive index and the presence of off-axis current drive.

  9. Impact of environmental contamination on laser induced damage of silica optics in Laser MegaJoule

    International Nuclear Information System (INIS)

    Bien-Aime, K.

    2009-11-01

    Laser induced damage impact of molecular contamination on fused polished silica samples in a context of high power laser fusion facility, such as Laser MegaJoule (LMJ) has been studied. One of the possible causes of laser induced degradation of optical component is the adsorption of molecular or particular contamination on optical surfaces. In the peculiar case of LMJ, laser irradiation conditions are a fluence of 10 J/cm 2 , a wavelength of 351 nm, a pulse duration of 3 ns for a single shot/days frequency. Critical compounds have been identified thanks to environmental measurements, analysis of material outgassing, and identification of surface contamination in the critical environments. Experiments of controlled contamination involving these compounds have been conducted in order to understand and model mechanisms of laser damage. Various hypotheses are proposed to explain the damage mechanism. (author)

  10. Development of a Single-Frequency Narrow Linewidth 1.5mm Semiconductor Laser Suitable for Spaceflight Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Many space applications rely on the utilization of Light Detection and Raging (LIDAR) techniques. A key component of any LIDAR system is the laser source. Single...

  11. Tunable Single Frequency 2.054 Micron Fiber Laser Using New Ho-Doped Fiber, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a near 2 micron widely tunable, narrow linewidth, single frequency fiber laser by developing an innovative...

  12. Tunable Single Frequency 2.05 Micron Fiber Laser Using New Ho-Doped Fiber, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a widely tunable, narrow linewidth, single frequency fiber laser near 2.05 micron by developing an innovative...

  13. Development of a Single-Frequency Narrow Linewidth 1.5mm Semiconductor Laser Suitable for Spaceflight Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase II proposal we plan to design and develop a semiconductor, low phase/frequency noise, single-frequency, external cavity semiconductor laser (ECL)...

  14. A diode laser stabilization scheme for {sup 40}Ca{sup +} single-ion spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, F; Almendros, M; Schuck, C; Huwer, J; Hennrich, M; Eschner, J, E-mail: felix.rohde@icfo.e [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, E-08860 Castelldefels, Barcelona (Spain)

    2010-06-14

    We present a scheme for stabilizing multiple lasers at wavelengths between 795 and 866 nm to the same atomic reference line. A reference laser at 852 nm is stabilized to the Cs D{sub 2} line using a Doppler-free frequency modulation technique. Through transfer cavities, four lasers are stabilized to the relevant atomic transitions in {sup 40}Ca{sup +}. The rms linewidth of a transfer-locked laser is measured to be 123 kHz over 200 ms with respect to an independent atomic reference, the Rb D{sub 1} line. This stability is confirmed by the comparison of an excitation spectrum of a single {sup 40}Ca{sup +} ion to an eight-level Bloch equation model. The long-term stability with respect to the same reference is measured to be 130 kHz over a period of 2 h. The high degree of stability is demonstrated by the measured Allan deviation around 10{sup -11} between 1 and 100 s.

  15. Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

    2008-03-23

    The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

  16. Computer simulations of a single-laser double-gas-jet wakefield accelerator concept

    Directory of Open Access Journals (Sweden)

    R. G. Hemker

    2002-04-01

    Full Text Available We report in this paper on full scale 2D particle-in-cell simulations investigating laser wakefield acceleration. First we describe our findings of electron beam generation by a laser propagating through a single gas jet. Using realistic parameters which are relevant for the experimental setup in our laboratory we find that the electron beam resulting after the propagation of a 0.8 μm, 50 fs laser through a 1.5 mm gas jet has properties that would make it useful for further acceleration. Our simulations show that the electron beam is generated when the laser exits the gas jet, and the properties of the generated beam, especially its energy, depend only weakly on most properties of the gas jet. We therefore propose to use the first gas jet as a plasma cathode and then use a second gas jet placed immediately behind the first to provide additional acceleration. Our simulations of this proposed setup indicate the feasibility of this idea and also suggest ways to optimize the quality of the resulting beam.

  17. Preparation of single rice chromosome for construction of a DNA library using a laser microbeam trap.

    Science.gov (United States)

    Liu, Xiaohui; Wang, Haowei; Li, Yinmei; Tang, Yesheng; Liu, Yilei; Hu, Xin; Jia, Peixin; Ying, Kai; Feng, Qi; Guan, Jianping; Jin, Chaoqing; Zhang, Lei; Lou, Liren; Zhou, Zhuan; Han, Bin

    2004-04-29

    We report the development of a laser micromanipulation system and its application in the isolation of individual rice chromosomes directly from a metaphase cell. Microdissection and flow sorting are two major methods for the isolation of single chromosome. These methods are dependent on the techniques of chromosome spread and chromosome suspension, respectively. In the development of this system, we avoided using chromosome spread and cell suspension was used instead. The cell wall of metaphase rice cell was cut by optical scissors. The released single chromosome was captured by an optical trap and transported to an area without cell debris. The isolated single chromosome was then collected and specific library was constructed by linker adaptor PCR. The average insert size of the library was about 300 bp. Two hundred inserts of chromosome 4 library were sequenced, and 96.5% were aligned to the corresponding sequences of rice chromosome 4. These results suggest the possible application of this method for the preparation of other subcellular structures and for the cloning of single macromolecule through a laser microbeam trap.

  18. Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin

    Science.gov (United States)

    Archilla, José R. F.; Moreira, Maria S. N. A.; Miyagi, Sueli P. H.; Bombana, Antônio C.; Gutknecht, Norbert; Marques, Márcia M.

    2012-11-01

    Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124 J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p≤0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

  19. Single session of Nd:YAG laser intracanal irradiation neutralizes endotoxin in dental root dentin.

    Science.gov (United States)

    Archilla, José R F; Moreira, Maria S N A; Miyagi, Sueli P H; Bombana, Antônio C; Gutknecht, Norbert; Marques, Márcia M

    2012-11-01

    Endotoxins released in the dental root by Gram-negative microorganisms can be neutralized by calcium hydroxide, when this medication is applied inside the root canal for at least seven days. However, several clinical situations demand faster root canal decontamination. Thus, for faster endotoxin neutralization, endodontists are seeking additional treatments. The in vitro study tested whether or not intracanal Nd:YAG laser irradiation would be able to neutralize endotoxin within the human dental root canal in a single session. Twenty-four human teeth with one root were mounted between two chambers. After conventional endodontic treatment, root canals were contaminated with Escherichia coli endotoxin. Then they were irradiated or not (controls) in contact mode with an Nd:YAG laser (1.5 W, 15 Hz, 100 mJ and pulse fluency of 124  J/cm2). The endotoxin activity was measured using the limulus lysate technique and data were statistically compared (p≤0.05). The concentration of active endotoxin measured in the negative control group was significantly lower than that of the positive control group (p=0.04). The concentrations of endotoxin in both irradiated groups were significantly lower than that of the positive control group (p=0.027) and similar to that of negative control group (p=0.20). A single session of intracanal Nd:YAG laser irradiation is able to neutralize endotoxin in the dental root tissues.

  20. Low-complexity full-melt laser-anneal process for fabrication of low-leakage implanted ultrashallow junctions

    NARCIS (Netherlands)

    Biasotto, C.; Gonda, V.; Nanver, L.K.; Scholtes, T.L.M.; Van der Cingel, J.; Vidal, D.; Jovanovic, V.

    2011-01-01

    Good-quality ultrashallow n + p junctions are formed using 5-keV amorphizing As+ implantations followed by a single-shot excimer laser anneal for dopant activation. By using an implant that is self-aligned to the contact windows etched in an oxide isolation layer, straightforward processing of the

  1. Development and characterization of a single particle laser ablation mass spectrometer (SPLAM for organic aerosol studies

    Directory of Open Access Journals (Sweden)

    F. Gaie-Levrel

    2012-01-01

    Full Text Available A single particle instrument was developed for real-time analysis of organic aerosol. This instrument, named Single Particle Laser Ablation Mass Spectrometry (SPLAM, samples particles using an aerodynamic lens system for which the theoretical performances were calculated. At the outlet of this system, particle detection and sizing are realized by using two continuous diode lasers operating at λ = 403 nm. Polystyrene Latex (PSL, sodium chloride (NaCl and dioctylphtalate (DOP particles were used to characterize and calibrate optical detection of SPLAM. The optical detection limit (DL and detection efficiency (DE were determined using size-selected DOP particles. The DE ranges from 0.1 to 90% for 100 and 350 nm DOP particles respectively and the SPLAM instrument is able to detect and size-resolve particles as small as 110–120 nm. During optical detection, particle scattered light from the two diode lasers, is detected by two photomultipliers and the detected signals are used to trigger UV excimer laser (λ = 248 nm used for one-step laser desorption ionization (LDI of individual aerosol particles. The formed ions are analyzed by a 1 m linear time-of-flight mass spectrometer in order to access to the chemical composition of individual particles. The TOF-MS detection limit for gaseous aromatic compounds was determined to be 0.85 × 10−15 kg (∼4 × 103 molecules. DOP particles were also used to test the overall operation of the instrument. The analysis of a secondary organic aerosol, formed in a smog chamber by the ozonolysis of indene, is presented as a first application of the instrument. Single particle mass spectra were obtained with an effective hit rate of 8%. Some of these mass spectra were found to be very different from one particle to another possibly reflecting chemical differences within the investigated indene SOA particles. Our study shows that an exhaustive statistical analysis, over hundreds of particles

  2. Rotary peening with captive shot

    International Nuclear Information System (INIS)

    1998-02-01

    Roto Peen with captive shot removes coatings and surface contamination from concrete floors. The objective of treating radioactively contaminated concrete floors during the Deactivation and Decommissioning (D and D) process is to reduce the surface contamination levels to meet regulatory criteria for unrestricted use. The US Department of Energy (DOE) Chicago Operations office and DOE's Federal Energy Technology Center (FETC) jointly sponsored a Large-Scale Demonstration Project (LSDP) at the Chicago Pile-5 Research Reactor (CP-5) at Argonne National Laboratory-East (ANL). The objective of the LSDP is to demonstrate potentially beneficial D and D technologies in comparison with current baseline technologies. As part of the LSDP, roto Peen with captive shot was demonstrated March 17--20, 1997, to treat a 20 x 25 ft area of radioactively contaminated concrete floor on the service level of the CP-5 building

  3. The Problem of Shot Selection in Basketball

    Science.gov (United States)

    Skinner, Brian

    2012-01-01

    In basketball, every time the offense produces a shot opportunity the player with the ball must decide whether the shot is worth taking. In this article, I explore the question of when a team should shoot and when they should pass up the shot by considering a simple theoretical model of the shot selection process, in which the quality of shot opportunities generated by the offense is assumed to fall randomly within a uniform distribution. Within this model I derive an answer to the question “how likely must the shot be to go in before the player should take it?” and I show that this lower cutoff for shot quality depends crucially on the number of shot opportunities remaining (say, before the shot clock expires), with larger demanding that only higher-quality shots should be taken. The function is also derived in the presence of a finite turnover rate and used to predict the shooting rate of an optimal-shooting team as a function of time. The theoretical prediction for the optimal shooting rate is compared to data from the National Basketball Association (NBA). The comparison highlights some limitations of the theoretical model, while also suggesting that NBA teams may be overly reluctant to shoot the ball early in the shot clock. PMID:22295109

  4. The problem of shot selection in basketball.

    Directory of Open Access Journals (Sweden)

    Brian Skinner

    Full Text Available In basketball, every time the offense produces a shot opportunity the player with the ball must decide whether the shot is worth taking. In this article, I explore the question of when a team should shoot and when they should pass up the shot by considering a simple theoretical model of the shot selection process, in which the quality of shot opportunities generated by the offense is assumed to fall randomly within a uniform distribution. Within this model I derive an answer to the question "how likely must the shot be to go in before the player should take it?" and I show that this lower cutoff for shot quality f depends crucially on the number n of shot opportunities remaining (say, before the shot clock expires, with larger n demanding that only higher-quality shots should be taken. The function f(n is also derived in the presence of a finite turnover rate and used to predict the shooting rate of an optimal-shooting team as a function of time. The theoretical prediction for the optimal shooting rate is compared to data from the National Basketball Association (NBA. The comparison highlights some limitations of the theoretical model, while also suggesting that NBA teams may be overly reluctant to shoot the ball early in the shot clock.

  5. Optical characteristics of modified fiber tips in single fiber, laser Doppler flowmetry

    Science.gov (United States)

    Oberg, P. Ake; Cai, Hongming; Rohman, Hakan; Larsson, Sven-Erik

    1994-02-01

    Percutaneous laser Doppler flowmetry (LDF) and bipolar surface electromyography (EMG) were used simultaneously for measurement of skeletal muscle (trapezius) perfusion in relation to static load and fatigue. On-line computer (386 SX) processing of the LDF- and EMG- signals made possible interpretation of the relationship between the perfusion and the activity of the muscle. The single fiber laser Doppler technique was used in order to minimize the trauma. A ray-tracing program was developed in the C language by which the optical properties of the fiber and fiber ends could be simulated. Isoirradiance graphs were calculated for three fiber end types and the radiance characteristics were measured for each fiber end. The three types of fiber-tips were evaluated and compared in flow model measurements.

  6. Characterisation of a cryostat using simultaneous, single-beam multiple-surface laser vibrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kissinger, Thomas; Charrett, Thomas O. H.; James, Stephen W.; Tatam, Ralph P., E-mail: r.p.tatam@cranfield.ac.uk [Engineering Photonics, Cranfield University, Cranfield, MK43 0AL (United Kingdom); Adams, Alvin; Twin, Andrew [Oxford Instruments Nanoscience, Tubney Woods, Abingdon, Oxon, OX13 5QX (United Kingdom)

    2016-06-28

    A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm · Hz{sup −05}. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder target inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the target, allowing any resonances to be identified.

  7. Fast all-optical flip-flop based on a single distributed feedback laser diode.

    Science.gov (United States)

    Huybrechts, Koen; Morthier, Geert; Baets, Roel

    2008-07-21

    Since there is an increasing demand for fast networks and switches, the electronic data processing imposes a severe bottleneck and all-optical processing techniques will be required in the future. All-optical flip-flops are one of the key components because they can act as temporary memory elements. Several designs have already been demonstrated but they are often relatively slow or complex to fabricate. We demonstrate experimentally fast flip-flop operation in a single DFB laser diode which is one of the standard elements in today's telecommunication industry. Injecting continuous wave light in the laser diode, a bistability is obtained due to the spatial hole burning effect. We can switch between the two states by using pulses with energies below 200 fJ resulting in flip-flop operation with switching times below 75 ps and repetition rates of up to 2 GHz.

  8. Room temperature single longitudinal mode laser output at 1645 nm from a laser-diode pumped Er:YAG nonplanar ring oscillator.

    Science.gov (United States)

    Yao, B Q; Yu, X; Liu, X L; Duan, X M; Ju, Y L; Wang, Y Z

    2013-04-08

    We report on a monolithic 1645 nm Er:YAG nonplanar ring oscillator (NPRO) resonantly pumped by a fiber-coupled laser diode. In the experiment, an up to 550 mW single frequency laser output at 1645.2 nm was obtained, corresponding to a slope efficiency of 19.1% and an absolute efficiency of 6.0%. The beam quality M2 was measured to be 2.1 at the highest output power.

  9. Laser-assisted fabrication of single-layer flexible touch sensor

    Science.gov (United States)

    Son, Seokwoo; Park, Jong Eun; Lee, Joohyung; Yang, Minyang; Kang, Bongchul

    2016-10-01

    Single-layer flexible touch sensor that is designed for the indium-tin-oxide (ITO)-free, bendable, durable, multi-sensible, and single layer transparent touch sensor was developed via a low-cost and one-step laser-induced fabrication technology. To this end, an entirely novel approach involving material, device structure, and even fabrication method was adopted. Conventional metal oxides based multilayer touch structure was substituted by the single layer structure composed of integrated silver wire networks of sensors and bezel interconnections. This structure is concurrently fabricated on a glass substitutive plastic film via the laser-induced fabrication method using the low-cost organometallic/nanoparticle hybrid complex. In addition, this study addresses practical solutions to heterochromia and interference problem with a color display unit. As a result, a practical touch sensor is successfully demonstrated through resolving the heterochromia and interference problems with color display unit. This study could provide the breakthrough for early realization of wearable device.

  10. [The determination of the distance of a shot from a smooth-bore weapon based on the damages from the action of the wad containers].

    Science.gov (United States)

    Korniiash, V A; Iodes, Iu V; Goloshchapov, I V

    1989-01-01

    Experimental shots from a No. 16 calibre single-barrelled gun using commercial cartridges in the plastic cartridge cases supplied by wad containers with Nos. 1 and 2 shots revealed that lesions that had typical morphologic structure which were characteristic of wad container action were produced at close distances (less than 2 meters). Therefore preliminary experimental shots are necessary before making concrete decisions on characteristic features of an injuring projectile and shot distance.

  11. Few-femtosecond time-resolved measurements of X-ray free-electron lasers.

    Science.gov (United States)

    Behrens, C; Decker, F-J; Ding, Y; Dolgashev, V A; Frisch, J; Huang, Z; Krejcik, P; Loos, H; Lutman, A; Maxwell, T J; Turner, J; Wang, J; Wang, M-H; Welch, J; Wu, J

    2014-04-30

    X-ray free-electron lasers, with pulse durations ranging from a few to several hundred femtoseconds, are uniquely suited for studying atomic, molecular, chemical and biological systems. Characterizing the temporal profiles of these femtosecond X-ray pulses that vary from shot to shot is not only challenging but also important for data interpretation. Here we report the time-resolved measurements of X-ray free-electron lasers by using an X-band radiofrequency transverse deflector at the Linac Coherent Light Source. We demonstrate this method to be a simple, non-invasive technique with a large dynamic range for single-shot electron and X-ray temporal characterization. A resolution of less than 1 fs root mean square has been achieved for soft X-ray pulses. The lasing evolution along the undulator has been studied with the electron trapping being observed as the X-ray peak power approaches 100 GW.

  12. Hybrid subtractive-additive-welding microfabrication for lab-on-chip applications via single amplified femtosecond laser source

    Science.gov (United States)

    Jonušauskas, Linas; Rekštytė, Sima; Buividas, Ričardas; Butkus, Simas; Gadonas, Roaldas; Juodkazis, Saulius; Malinauskas, Mangirdas

    2017-09-01

    An approach employing ultrafast laser hybrid subtractive-additive microfabrication, which combines ablation, three-dimensional nanolithography, and welding, is proposed for the realization of a lab-on-chip (LOC) device. A single amplified Yb:KGW femtosecond (fs)-pulsed laser source is shown to be suitable for fabricating microgrooves in glass slabs, polymerization of fine-meshes microfilter out of hybrid organic-inorganic photopolymer SZ2080 inside them, and, finally, sealing the whole chip with cover glass into a single monolithic piece. The created microfluidic device proved its particle sorting function by separating 1- and 10-μm polystyrene spheres in an aqueous mixture. All together, this proves that laser microfabrication based on a single amplified fs laser source is a flexible and versatile approach for the hybrid subtractive-additive manufacturing of functional mesoscale multimaterial LOC devices.

  13. Single tunable laser interrogation of slab-coupled optical sensors through resonance tuning.

    Science.gov (United States)

    Chadderdon, Spencer; Woodard, Leeland; Perry, Daniel; Selfridge, Richard H; Schultz, Stephen M

    2013-04-20

    This paper describes a method for tuning the resonant wavelengths of slab-coupled optical fiber sensors (SCOSs). This method allows multiple sensors to be interrogated simultaneously with a single tunable laser. The resonances are tuned by rotating a biaxial slab waveguide relative to an optical D-fiber. As the slab waveguide rotates, its effective index of refraction changes causing the coupling wavelengths of the slab waveguide and D-fiber to shift. A SCOS fabricated with potassium titanyl phosphate crystal as the slab waveguide is shown to have resonance tuning ranges of 6.67 and 22.24 nm, respectively, for TM and TE polarized modes.

  14. Application of optical single-sideband laser in Raman atom interferometry

    Science.gov (United States)

    Zhu, Lingxiao; Lien, Yu-Hung; Hinton, Andrew; Niggebaum, Alexander; Rammeloo, Clemens; Bongs, Kai; Holynski, Michael

    2018-03-01

    A frequency doubled I/Q modulator based optical single-sideband (OSSB) laser system is demonstrated for atomic physics research, specifically for atom interferometry where the presence of additional sidebands causes parasitic transitions. The performance of the OSSB technique and the spectrum after second harmonic generation are measured and analyzed. The additional sidebands are removed with better than 20 dB suppression, and the influence of parasitic transitions upon stimulated Raman transitions at varying spatial positions is shown to be removed beneath experimental noise. This technique will facilitate the development of compact atom interferometry based sensors with improved accuracy and reduced complexity.

  15. Nonlinear Spectral Signatures and Spatiotemporal Behavior of Stimulated Raman Scattering from Single Laser Speckles

    International Nuclear Information System (INIS)

    Vu, H.X.; Yin, L.; DuBois, D.F.; Bezzerides, B.; Dodd, E.S.

    2005-01-01

    Simulations are reported of the Thomson scatter spectrum of electrostatic waves (ESWs) excited in single laser hot spots by backward stimulated Raman scattering (BSRS). Under conditions similar those in the recent experiments of Kline et al. [Phys. Rev. Lett. 94, 175003 (2005)], a spectral streak, resulting from the trapping-induced frequency shift of the ESW, is found for high wave-number ESWs, similar to the observations. This shift and parametric frequency matching lead to isolated BSRS pulses. Modes with acoustic dispersion, resulting from the trapping-modified electron velocity distribution, can enhance the frequency range of the streak

  16. Effects of underwater turbulence on laser beam propagation and coupling into single-mode optical fiber.

    Science.gov (United States)

    Hanson, Frank; Lasher, Mark

    2010-06-01

    We characterize and compare the effects of turbulence on underwater laser propagation with theory. Measurements of the coupling efficiency of the focused beam into a single-mode fiber are reported. A simple tip-tilt control system, based on the position of the image centroid in the focal plane, was shown to maintain good coupling efficiency for a beam radius equal to the transverse coherence length, r(0). These results are relevant to high bandwidth communication technology that requires good spatial mode quality.

  17. Microsecond fiber laser pumped, single-frequency optical parametric oscillator for trace gas detection.

    Science.gov (United States)

    Barria, Jessica Barrientos; Roux, Sophie; Dherbecourt, Jean-Baptiste; Raybaut, Myriam; Melkonian, Jean-Michel; Godard, Antoine; Lefebvre, Michel

    2013-07-01

    We report on the first microsecond doubly resonant optical parametric oscillator (OPO). It is based on a nested cavity OPO architecture allowing single longitudinal mode operation and low oscillation threshold (few microjoule). The combination with a master oscillator-power amplifier fiber pump laser provides a versatile optical source widely tunable in the 3.3-3.5 μm range with an adjustable pulse repetition rate (from 40 to 100 kHz), high duty cycle (~10(-2)) and mean power (up to 25 mW in the idler beam). The potential for trace gas sensing applications is demonstrated through photoacoustic detection of atmospheric methane.

  18. High-aspect-ratio grooves fabricated in silicon by a single pass of femtosecond laser pulses

    International Nuclear Information System (INIS)

    Ma Yuncan; Shi Haitao; Si Jinhai; Ren Hai; Chen Tao; Chen Feng; Hou Xun

    2012-01-01

    High-aspect-ratio grooves have been fabricated in silicon by a single pass of femtosecond laser pulses in water and ambient air. Scanning electron microscopy and energy dispersive x-ray spectroscopy were employed to image for the morphology of the photoinduced grooves and analyze the chemical composition in the surrounding of the grooves. It was observed that the sidewall of the grooves fabricated in water was much smoother than that in ambient air, and there were homogeneous nano-scale protrusions on the sidewall of the grooves fabricated in water. Meanwhile, oxygen species, which was incorporated into the grooves fabricated in air, was not observed in those in water.

  19. Semantic Shot Classification in Sports Video

    Science.gov (United States)

    Duan, Ling-Yu; Xu, Min; Tian, Qi

    2003-01-01

    In this paper, we present a unified framework for semantic shot classification in sports videos. Unlike previous approaches, which focus on clustering by aggregating shots with similar low-level features, the proposed scheme makes use of domain knowledge of a specific sport to perform a top-down video shot classification, including identification of video shot classes for each sport, and supervised learning and classification of the given sports video with low-level and middle-level features extracted from the sports video. It is observed that for each sport we can predefine a small number of semantic shot classes, about 5~10, which covers 90~95% of sports broadcasting video. With the supervised learning method, we can map the low-level features to middle-level semantic video shot attributes such as dominant object motion (a player), camera motion patterns, and court shape, etc. On the basis of the appropriate fusion of those middle-level shot classes, we classify video shots into the predefined video shot classes, each of which has a clear semantic meaning. The proposed method has been tested over 4 types of sports videos: tennis, basketball, volleyball and soccer. Good classification accuracy of 85~95% has been achieved. With correctly classified sports video shots, further structural and temporal analysis, such as event detection, video skimming, table of content, etc, will be greatly facilitated.

  20. Interaction of single-pulse laser energy with bow shock in hypersonic flow

    Directory of Open Access Journals (Sweden)

    Hong Yanji

    2014-04-01

    Full Text Available Pressure sensing and schlieren imaging with high resolution and sensitivity are applied to the study of the interaction of single-pulse laser energy with bow shock at Mach 5. An Nd:YAG laser operated at 1.06 μm, 100 mJ pulse energy is used to break down the hypersonic flow in a shock tunnel. Three-dimensional Navier–Stokes equations are solved with an upwind scheme to simulate the interaction. The pressure at the stagnation point on the blunt body is measured and calculated to examine the pressure variation during the interaction. Schlieren imaging is used in conjunction with the calculated density gradients to examine the process of the interaction. The results show that the experimental pressure at the stagnation point on the blunt body and schlieren imaging fit well with the simulation. The pressure at the stagnation point on the blunt body will increase when the transmission shock approaches the blunt body and decrease with the formation of the rarefied wave. Bow shock is deformed during the interaction. Quasi-stationary waves are formed by high rate laser energy deposition to control the bow shock. The pressure and temperature at the stagnation point on the blunt body and the wave drag are reduced to 50%, 75% and 81% respectively according to the simulation. Schlieren imaging has provided important information for the investigation of the mechanism of the interaction.

  1. Single-mode Rayleigh-Taylor growth-rate measurements with the OMEGA laser system

    International Nuclear Information System (INIS)

    Knauer, J.P.; Verdon, C.P.; Meyerhofer, D.D.; Boehly, T.R.; Bradley, D.K.; Smalyuk, V.A.; Ofer, D.; McKenty, P.W.; Glendinning, S.G.; Kalantar, D.H.; Watt, R.G.; Gobby, P.L.; Willi, O.; Taylor, R.J.

    1997-01-01

    The results from a series of single-mode Rayleigh-Taylor (RT) instability growth experiments performed on the OMEGA laser system using planar targets are reported. Planar targets with imposed mass perturbations were accelerated using five to six 351-nm laser beams overlapped with total intensities up to 2.5x10 14 W/cm 2 . Experiments were performed with both 3-ns ramp and 3-ns flat-topped temporal pulse shapes. The use of distributed phase plates and smoothing by spectral dispersion resulted in a laser-irradiation nonuniformity of 4%endash 7% over a 600-μm-diam region defined by the 90% intensity contour. The temporal growth of the modulation in optical depth was measured using through-foil radiography and was detected with an x-ray framing camera for CH targets with and without a foam buffer. The growth of both 31-μm and 60-μm wavelength perturbations was found to be in good agreement with ORCHID simulations when the experimental details, including noise, were included. The addition of a 30-mg/cc, 100-μm-thick polystyrene foam buffer layer resulted in reduced growth of the 31-μm perturbation and essentially unchanged growth for the 60-μm case when compared to targets without foam. copyright 1997 American Institute of Physics

  2. Geometry modeling of single track cladding deposited by high power diode laser with rectangular beam spot

    Science.gov (United States)

    Liu, Huaming; Qin, Xunpeng; Huang, Song; Hu, Zeqi; Ni, Mao

    2018-01-01

    This paper presents an investigation on the relationship between the process parameters and geometrical characteristics of the sectional profile for the single track cladding (STC) deposited by High Power Diode Laser (HPDL) with rectangle beam spot (RBS). To obtain the geometry parameters, namely cladding width Wc and height Hc of the sectional profile, a full factorial design (FFD) of experiment was used to conduct the experiments with a total of 27. The pre-placed powder technique has been employed during laser cladding. The influence of the process parameters including laser power, powder thickness and scanning speed on the Wc and Hc was analyzed in detail. A nonlinear fitting model was used to fit the relationship between the process parameters and geometry parameters. And a circular arc was adopted to describe the geometry profile of the cross-section of STC. The above models were confirmed by all the experiments. The results indicated that the geometrical characteristics of the sectional profile of STC can be described as the circular arc, and the other geometry parameters of the sectional profile can be calculated only using Wc and Hc. Meanwhile, the Wc and Hc can be predicted through the process parameters.

  3. ZnO thin films on single carbon fibres fabricated by Pulsed Laser Deposition (PLD)

    Energy Technology Data Exchange (ETDEWEB)

    Krämer, André; Engel, Sebastian [Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena (Germany); Sangiorgi, Nicola [Institute of Science and Technology for Ceramics – National Research Council of Italy (CNR-ISTEC), via Granarolo 64, 48018 Faenza, RA (Italy); Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica, 00133 Rome (Italy); Sanson, Alessandra [Institute of Science and Technology for Ceramics – National Research Council of Italy (CNR-ISTEC), via Granarolo 64, 48018 Faenza, RA (Italy); Bartolomé, Jose F. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), C/Sor Juana Inés de la Cruz 3, 28049 Madrid (Spain); Gräf, Stephan, E-mail: stephan.graef@uni-jena.de [Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena (Germany); Müller, Frank A. [Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena (Germany); Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Philosophenweg 7a, 07743 Jena (Germany)

    2017-03-31

    Highlights: • Carbon fibres were entirely coated with thin films consisting of aligned ZnO crystals. • A Q-switched CO2 laser was utilised as radiation source. • Suitability of ZnO thin films on carbon fibres as photo anodes for DSSC was studied. - Abstract: Single carbon fibres were 360° coated with zinc oxide (ZnO) thin films by pulsed laser deposition using a Q-switched CO{sub 2} laser with a pulse duration τ ≈ 300 ns, a wavelength λ = 10.59 μm, a repetition frequency f{sub rep} = 800 Hz and a peak power P{sub peak} = 15 kW in combination with a 3-step-deposition technique. In a first set of experiments, the deposition process was optimised by investigating the crystallinity of ZnO films on silicon and polished stainless steel substrates. Here, the influence of the substrate temperature and of the oxygen partial pressure of the background gas were characterised by scanning electron microscopy and X-ray diffraction analyses. ZnO coated carbon fibres and conductive glass sheets were used to prepare photo anodes for dye-sensitised solar cells in order to investigate their suitability for energy conversion devices. To obtain a deeper insight of the electronic behaviour at the interface between ZnO and substrate I–V measurements were performed.

  4. Characterization of Plant Growth under Single-Wavelength Laser Light Using the Model Plant Arabidopsis Thaliana

    KAUST Repository

    Ooi, Amanda

    2016-12-01

    Indoor horticulture offers a promising solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available lighting is suboptimal, therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. Lasers are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Besides, laser beams can be tailored to match the absorption profiles of different plants. We have developed a prototype laser growth chamber and demonstrate that laser-grown plants can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteomic data show that the singlewavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture. Furthermore, stomatal movement partly determines the plant productivity and stress management. Abscisic acid (ABA) induces stomatal closure by promoting net K+-efflux from guard cells through outwardrectifying K+ (K+ out) channels to regulate plant water homeostasis. Here, we show that the Arabidopsis thaliana guard cell outward-rectifying K+ (ATGORK) channel is a direct target for ABA in the regulation of stomatal aperture and hence gas exchange and transpiration. Addition of (±)-ABA, but not the biologically inactive (−)-isomer, increases K+ out channel activity in Vicia faba guard cell protoplast. A similar ABA

  5. Laser writing of single-crystalline gold substrates for surface enhanced Raman spectroscopy

    Science.gov (United States)

    Singh, Astha; Sharma, Geeta; Ranjan, Neeraj; Mittholiya, Kshitij; Bhatnagar, Anuj; Singh, B. P.; Mathur, Deepak; Vasa, Parinda

    2017-07-01

    Surface enhanced Raman scattering (SERS) spectroscopy, a powerful contemporary tool for studying low-concentration analytes via surface plasmon induced enhancement of local electric field, is of utility in biochemistry, material science, threat detection, and environmental studies. We have developed a simple, fast, scalable, and relatively low-cost optical method of fabricating and characterizing large-area, reusable and broadband SERS substrates with long storage lifetime. We use tightly focused, intense infra-red laser pulses to write gratings on single-crystalline, Au (1 1 1) gold films on mica which act as SERS substrates. Our single-crystalline SERS substrates compare favourably, in terms of surface quality and roughness, to those fabricated in poly-crystalline Au films. Tests show that our SERS substrates have the potential of detecting urea and 1,10-phenantroline adulterants in milk and water, respectively, at 0.01 ppm (or lower) concentrations.

  6. SINGLE TREE DETECTION FROM AIRBORNE LASER SCANNING DATA USING A MARKED POINT PROCESS BASED METHOD

    Directory of Open Access Journals (Sweden)

    J. Zhang

    2013-05-01

    Full Text Available Tree detection and reconstruction is of great interest in large-scale city modelling. In this paper, we present a marked point process model to detect single trees from airborne laser scanning (ALS data. We consider single trees in ALS recovered canopy height model (CHM as a realization of point process of circles. Unlike traditional marked point process, we sample the model in a constraint configuration space by making use of image process techniques. A Gibbs energy is defined on the model, containing a data term which judge the fitness of the model with respect to the data, and prior term which incorporate the prior knowledge of object layouts. We search the optimal configuration through a steepest gradient descent algorithm. The presented hybrid framework was test on three forest plots and experiments show the effectiveness of the proposed method.

  7. Single-Molecule Imaging with X-Ray Free-Electron Lasers: Dream or Reality?

    KAUST Repository

    Fratalocchi, Andrea

    2011-03-09

    X-ray free-electron lasers (XFEL) are revolutionary photon sources, whose ultrashort, brilliant pulses are expected to allow single-molecule diffraction experiments providing structural information on the atomic length scale of nonperiodic objects. This ultimate goal, however, is currently hampered by several challenging questions basically concerning sample damage, Coulomb explosion, and the role of nonlinearity. By employing an original ab initio approach, we address these issues showing that XFEL-based single-molecule imaging will be only possible with a few-hundred long attosecond pulses, due to significant radiation damage and the formation of preferred multisoliton clusters which reshape the overall electronic density of the molecular system at the femtosecond scale.

  8. Single-Molecule Imaging with X-Ray Free-Electron Lasers: Dream or Reality?

    International Nuclear Information System (INIS)

    Fratalocchi, A.; Ruocco, G.

    2011-01-01

    X-ray free-electron lasers (XFEL) are revolutionary photon sources, whose ultrashort, brilliant pulses are expected to allow single-molecule diffraction experiments providing structural information on the atomic length scale of nonperiodic objects. This ultimate goal, however, is currently hampered by several challenging questions basically concerning sample damage, Coulomb explosion, and the role of nonlinearity. By employing an original ab initio approach, we address these issues showing that XFEL-based single-molecule imaging will be only possible with a few-hundred long attosecond pulses, due to significant radiation damage and the formation of preferred multisoliton clusters which reshape the overall electronic density of the molecular system at the femtosecond scale.

  9. Analysis of morphology and residual porosity in selective laser melting of Fe powders using single track experiments

    Science.gov (United States)

    Shutov, I. V.; Gordeev, G. A.; Kharanzhevskiy, E. V.; Krivilyov, M. D.

    2017-04-01

    Morphology and residual porosity of single tracks obtained by pulse selective laser melting (SLM) of Fe powder have been studied by metallography. Multiple cross sections of the stainless substrate with the single tracks deposited by SLM are examined and classified depending on processing parameters. A sustainable scanning strategy to reduce residual porosity is suggested for pulse laser annealing. The developed method is suitable both for improvement of processing regimes in commercial SLM machines and validation of numerical models in additive manufacturing of metal parts. The effect of the beam radius, pulse energy, its frequency and duration on a shape of the single track and its adhesion to the substrate is revealed.

  10. Optics clustered to output unique solutions: a multi-laser facility for combined single molecule and ensemble microscopy.

    Science.gov (United States)

    Clarke, David T; Botchway, Stanley W; Coles, Benjamin C; Needham, Sarah R; Roberts, Selene K; Rolfe, Daniel J; Tynan, Christopher J; Ward, Andrew D; Webb, Stephen E D; Yadav, Rahul; Zanetti-Domingues, Laura; Martin-Fernandez, Marisa L

    2011-09-01

    Optics clustered to output unique solutions (OCTOPUS) is a microscopy platform that combines single molecule and ensemble imaging methodologies. A novel aspect of OCTOPUS is its laser excitation system, which consists of a central core of interlocked continuous wave and pulsed laser sources, launched into optical fibres and linked via laser combiners. Fibres are plugged into wall-mounted patch panels that reach microscopy end-stations in adjacent rooms. This allows multiple tailor-made combinations of laser colours and time characteristics to be shared by different end-stations minimising the need for laser duplications. This setup brings significant benefits in terms of cost effectiveness, ease of operation, and user safety. The modular nature of OCTOPUS also facilitates the addition of new techniques as required, allowing the use of existing lasers in new microscopes while retaining the ability to run the established parts of the facility. To date, techniques interlinked are multi-photon/multicolour confocal fluorescence lifetime imaging for several modalities of fluorescence resonance energy transfer (FRET) and time-resolved anisotropy, total internal reflection fluorescence, single molecule imaging of single pair FRET, single molecule fluorescence polarisation, particle tracking, and optical tweezers. Here, we use a well-studied system, the epidermal growth factor receptor network, to illustrate how OCTOPUS can aid in the investigation of complex biological phenomena. © 2011 American Institute of Physics

  11. Application of laser tweezers Raman spectroscopy techniques to the monitoring of single cell response to stimuli

    Science.gov (United States)

    Chan, James W.; Liu, Rui; Matthews, Dennis L.

    2012-06-01

    Laser tweezers Raman spectroscopy (LTRS) combines optical trapping with micro-Raman spectroscopy to enable label-free biochemical analysis of individual cells and small biological particles in suspension. The integration of the two technologies greatly simplifies the sample preparation and handling of suspension cells for spectroscopic analysis in physiologically meaningful conditions. In our group, LTRS has been used to study the effects of external perturbations, both chemical and mechanical, on the biochemistry of the cell. Single cell dynamics can be studied by performing longitudinal studies to continuously monitor the response of the cell as it interacts with its environment. The ability to carry out these measurements in-vitro makes LTRS an attractive tool for many biomedical applications. Here, we discuss the use of LTRS to study the response of cancer cells to chemotherapeutics and bacteria cells to antibiotics and show that the life cycle and apoptosis of the cells can be detected. These results show the promise of LTRS for drug discovery/screening, antibiotic susceptibility testing, and chemotherapy response monitoring applications. In separate experiments, we study the response of red blood cells to the mechanical forces imposed on the cell by the optical tweezers. A laser power dependent deoxygenation of the red blood cell in the single beam trap is reported. Normal, sickle cell, and fetal red blood cells have a different behavior that enables the discrimination of the cell types based on this mechanochemical response. These results show the potential utility of LTRS for diagnosing and studying red blood cell diseases.

  12. Laser microdissection and DNA typing of cells from single hair follicles.

    Science.gov (United States)

    Di Martino, D; Giuffrè, G; Staiti, N; Simone, A; Todaro, P; Saravo, L

    2004-12-02

    Isolation and identification of single cells from tissue samples or smears assume a great relevance in pathological and forensic applications; in this latter field, the possibility to identify a specific genetic profile can be obtained by short tandem repeat (STR) typing, allowing to achieve a scientific proof important in law courts. It is well known that DNA extraction may be performed from several tissue fragments, blood traces, spermatozoa as well as telogen hair. However, in the last case, few follicle cells are coupled to a great amount of keratin reducing the efficiency of DNA amplification. Recently, the introduction of laser microdissection technique has greatly improved the capability to select single cells without any cross-contamination. In the present report, we have performed a laser microdissection using a Leica AS LMD (Leica Microsystems, Germany), utilized on cutting the telogen hair in order to exclusively collect the lower part of the follicle and reduce keratin contamination. In this way we can accurately extract an adequate amount of DNA, successfully typed by STR profile.

  13. Large-Scale Mixed Temperate Forest Mapping at the Single Tree Level using Airborne Laser Scanning

    Science.gov (United States)

    Scholl, V.; Morsdorf, F.; Ginzler, C.; Schaepman, M. E.

    2017-12-01

    Monitoring vegetation on a single tree level is critical to understand and model a variety of processes, functions, and changes in forest systems. Remote sensing technologies are increasingly utilized to complement and upscale the field-based measurements of forest inventories. Airborne laser scanning (ALS) systems provide valuable information in the vertical dimension for effective vegetation structure mapping. Although many algorithms exist to extract single tree segments from forest scans, they are often tuned to perform well in homogeneous coniferous or deciduous areas and are not successful in mixed forests. Other methods are too computationally expensive to apply operationally. The aim of this study was to develop a single tree detection workflow using leaf-off ALS data for the canton of Aargau in Switzerland. Aargau covers an area of over 1,400km2 and features mixed forests with various development stages and topography. Forest type was classified using random forests to guide local parameter selection. Canopy height model-based treetop maxima were detected and maintained based on the relationship between tree height and window size, used as a proxy to crown diameter. Watershed segmentation was used to generate crown polygons surrounding each maximum. The location, height, and crown dimensions of single trees were derived from the ALS returns within each polygon. Validation was performed through comparison with field measurements and extrapolated estimates from long-term monitoring plots of the Swiss National Forest Inventory within the framework of the Swiss Federal Institute for Forest, Snow, and Landscape Research. This method shows promise for robust, large-scale single tree detection in mixed forests. The single tree data will aid ecological studies as well as forest management practices. Figure description: Height-normalized ALS point cloud data (top) and resulting single tree segments (bottom) on the Laegeren mountain in Switzerland.

  14. Impact of environmental contamination on laser induced damage of silica optics in Laser MegaJoule; Impact de l'environnement sur l'endommagement laser des optiques de silice du Laser MegaJoule

    Energy Technology Data Exchange (ETDEWEB)

    Bien-Aime, K.

    2009-11-15

    Laser induced damage impact of molecular contamination on fused polished silica samples in a context of high power laser fusion facility, such as Laser MegaJoule (LMJ) has been studied. One of the possible causes of laser induced degradation of optical component is the adsorption of molecular or particular contamination on optical surfaces. In the peculiar case of LMJ, laser irradiation conditions are a fluence of 10 J/cm{sup 2}, a wavelength of 351 nm, a pulse duration of 3 ns for a single shot/days frequency. Critical compounds have been identified thanks to environmental measurements, analysis of material outgassing, and identification of surface contamination in the critical environments. Experiments of controlled contamination involving these compounds have been conducted in order to understand and model mechanisms of laser damage. Various hypotheses are proposed to explain the damage mechanism. (author)

  15. Shot peening: theory applications and recent development

    International Nuclear Information System (INIS)

    Zaid, A.I.O.

    1999-01-01

    Shot peening is a surface treatment process by which the surface of an elastic-plastic target material is subjected to multiple impact by spherical shots made of glass or hard steel in a defined and controlled manner. The multiple impact produces a dynamic compressive stress at the surface of the target, thereby effectively improving its mechanical behavior and eliminates cracks and imperfections hence improving the fatigue life and strength. In this paper, the theory and practice of the shot peening process are reviewed. The main parameters involved in the process and their effects on shot peening are presented and discussed which include: shot material, size and geometry, shot pressure and shot velocity, projection angle, exposure time, table rotational speed, standoff distance coverage, saturation and peening intensity. Furthermore, the effect of shot peening on fatigue life and fatigue strength of ferrous and non-ferrous materials together with other different industrial applications of the process are given. Recent developments in utilizing the shot peening process with welded parts and hard chromium plating aiming at improvement of their fatigue strength and their resistance to stress corrosion cracking are also presented and discussed. Finally, future development of the process are outlined and discussed. (author)

  16. Improving accuracy of overhanging structures for selective laser melting through reliability characterization of single track formation on thick powder beds

    DEFF Research Database (Denmark)

    Mohanty, Sankhya; Hattel, Jesper Henri

    2016-01-01

    Repeatability and reproducibility of parts produced by selective laser melting is a standing issue, and coupled with a lack of standardized quality control presents a major hindrance towards maturing of selective laser melting as an industrial scale process. Consequently, numerical process...... modelling has been adopted towards improving the predictability of the outputs from the selective laser melting process. Establishing the reliability of the process, however, is still a challenge, especially in components having overhanging structures.In this paper, a systematic approach towards...... establishing reliability of overhanging structure production by selective laser melting has been adopted. A calibrated, fast, multiscale thermal model is used to simulate the single track formation on a thick powder bed. Single tracks are manufactured on a thick powder bed using same processing parameters...

  17. Tunable single-longitudinal-mode operation of an injection-locked TEA CO2 laser. [ozone absorption spectroscopy

    Science.gov (United States)

    Megie, G.; Menzies, R. T.

    1979-01-01

    The tunable single-longitudinal-mode operation of a TEA CO2 laser by an injection technique using a CW waveguide laser as the master oscillator is reported. With the experimental arrangement described, in which the waveguide laser frequency is tuned to correspond to one of the oscillating longitudinal modes of the TEA laser, single-longitudinal-mode operation was achieved with no apparent reduction in the TEA output energy, on various CO2 lines with frequency offsets from the line center as large as 300 MHz. The capability of this technique for high-resolution spectroscopy or atmospheric lidar studies is demonstrated by the recording of the absorption spectrum of a strong ozone line.

  18. Shot noise in radiobiological systems.

    Science.gov (United States)

    Datesman, A

    2016-11-01

    As a model for human tissue, this report considers the rate of free radical generation in a dilute solution of water in which a beta-emitting radionuclide is uniformly dispersed. Each decay dissipates a discrete quantity of energy, creating a large number of free radicals in a short time within a small volume determined by the beta particle range. Representing the instantaneous dissipated power as a train of randomly-spaced pulses, the time-averaged dissipated power p¯ and rate of free radical generation g¯ are derived. The analogous result in the theory of electrical circuits is known as the shot noise theorem. The reference dose of X-rays D ref producing an identical rate of free radical generation and level of oxidative stress is shown a) to increase with the square root of the absorbed dose, D, and b) to be far larger than D. This finding may have important consequences for public health in cases where the level of shot noise exceeds some noise floor corresponding to equilibrium biological processes. An estimate of this noise floor is made using the example of potassium-40, a beta-emitting radioisotope universally present in living tissue. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Digital algorithms for parallel pipelined single-detector homodyne fringe counting in laser interferometry

    Science.gov (United States)

    Rerucha, Simon; Sarbort, Martin; Hola, Miroslava; Cizek, Martin; Hucl, Vaclav; Cip, Ondrej; Lazar, Josef

    2016-12-01

    The homodyne detection with only a single detector represents a promising approach in the interferometric application which enables a significant reduction of the optical system complexity while preserving the fundamental resolution and dynamic range of the single frequency laser interferometers. We present the design, implementation and analysis of algorithmic methods for computational processing of the single-detector interference signal based on parallel pipelined processing suitable for real time implementation on a programmable hardware platform (e.g. the FPGA - Field Programmable Gate Arrays or the SoC - System on Chip). The algorithmic methods incorporate (a) the single detector signal (sine) scaling, filtering, demodulations and mixing necessary for the second (cosine) quadrature signal reconstruction followed by a conic section projection in Cartesian plane as well as (a) the phase unwrapping together with the goniometric and linear transformations needed for the scale linearization and periodic error correction. The digital computing scheme was designed for bandwidths up to tens of megahertz which would allow to measure the displacements at the velocities around half metre per second. The algorithmic methods were tested in real-time operation with a PC-based reference implementation that employed the advantage pipelined processing by balancing the computational load among multiple processor cores. The results indicate that the algorithmic methods are suitable for a wide range of applications [3] and that they are bringing the fringe counting interferometry closer to the industrial applications due to their optical setup simplicity and robustness, computational stability, scalability and also a cost-effectiveness.

  20. High luminous flux from single crystal phosphor-converted laser-based white lighting system

    KAUST Repository

    Cantore, Michael

    2015-12-14

    The efficiency droop of light emitting diodes (LEDs) with increasing current density limits the amount of light emitted per wafer area. Since low current densities are required for high efficiency operation, many LED die are needed for high power white light illumination systems. In contrast, the carrier density of laser diodes (LDs) clamps at threshold, so the efficiency of LDs does not droop above threshold and high efficiencies can be achieved at very high current densities. The use of a high power blue GaN-based LD coupled with a single crystal Ce-doped yttrium aluminum garnet (YAG:Ce) sample was investigated for white light illumination applications. Under CW operation, a single phosphor-converted LD (pc-LD) die produced a peak luminous efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD operating efficiency. These results show that a single pc-LD die is capable of emitting enough luminous flux for use in a high power white light illumination system.

  1. Impact of pulse duration on Ho:YAG laser lithotripsy: treatment aspects on the single-pulse level.

    Science.gov (United States)

    Sroka, Ronald; Pongratz, Thomas; Scheib, Gabriel; Khoder, Wael; Stief, Christian G; Herrmann, Thomas; Nagele, Udo; Bader, Markus J

    2015-04-01

    Holmium-YAG (Ho:YAG) laser lithotripsy is a multi-pulse treatment modality with stochastic effects on the fragmentation. In vitro investigation on the single-pulse-induced effects on fiber, repulsion as well as fragmentation was performed to identify potential impacts of different Ho:YAG laser pulse durations. A Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long- or short-pulse mode was tested with regard to fiber burn back, the repulsion capacity using an underwater pendulum setup and single-pulse-induced fragmentation capacity using artificial (BEGO) stones. The laser parameters were chosen in accordance with clinical application modes (laser fiber: 365 and 200 µm; output power: 4, 6 and 10 W in different combinations of energy per pulse and repetition rate). Evaluation parameters were reduction in fiber length, pendulum deviation and topology of the crater. Using the long-pulse mode, the fiber burn back was nearly negligible, while in short-pulse mode, an increased burn back could be observed. The results of the pendulum test showed that the deviation induced by the momentum of short pulses was by factor 1.5-2 higher compared to longer pulses at identical energy per pulse settings. The ablation volumes induced by single pulses either in short-pulse or long-pulse mode did not differ significantly although different crater shapes appeared. Reduced stone repulsion and reduced laser fiber burn back with longer laser pulses may result in a more convenient handling during clinical application and thus in an improved clinical outcome of laser lithotripsy.

  2. Single-longitudinal mode distributed-feedback fiber laser with low-threshold and high-efficiency

    Science.gov (United States)

    Jiang, Man; Zhou, Pu; Gu, Xijia

    2018-01-01

    Single-frequency fiber laser has attracted a lot of interest in recent years due to its numerous application potentials in telecommunications, LIDAR, high resolution sensing, atom frequency standard, etc. Phosphate glass fiber is one of the candidates for building compact high gain fiber lasers because of its capability of high-concentration of rare-earth ions doping in fiber core. Nevertheless, it is challenging for the integration of UV-written intra-core fiber Bragg gratings into the fiber laser cavity due to the low photosensitivity of phosphate glass fiber. The research presented in this paper will focus on demonstration of UV-written Bragg gratings in phosphate glass fiber and its application in direct-written short monolithic single-frequency fiber lasers. Strong π-phase shift Bragg grating structure is direct-inscribed into the Er/Yb co-doped gain fiber using an excimer laser, and a 5-cm-long phase mask is used to inscribe a laser cavity into the Er/Yb co-doped phosphate glass fibers. The phase mask is a uniform mask with a 50 μm gap in the middle. The fiber laser device emits output power of 10.44 mW with a slope efficiency of 21.5% and the threshold power is about 42.8 mW. Single-longitudinal mode operation is validated by radio frequency spectrum measurement. Moreover, the output spectrum at the highest power shows an excellent optical signal to noise ratio of about 70 dB. These results, to the best of our knowledge, show the lowest power threshold and highest efficiency among the reports that using the same structure to achieve single-longitudinal mode laser output.

  3. Single frequency 1645 nm Er:YAG nonplanar ring oscillator resonantly pumped by a 1470 nm laser diode.

    Science.gov (United States)

    Zheng, Yan; Gao, Chunqing; Wang, Ran; Gao, Mingwei; Ye, Qing

    2013-03-01

    A 1645 nm Er:YAG nonplanar ring oscillator, resonantly pumped by a 1470 nm laser diode, is reported. By using a 0.5%-doped Er:YAG nonplanar ring resonator, a 0.284 W single-frequency laser output at 1645 nm was obtained with a slope efficiency of 42.1%. The beam quality in x and y directions were 1.064 and 1.039, respectively.

  4. Single- and dual-wavelength laser pulses induced modification in 10×(Al/Ti)/Si multilayer system

    Energy Technology Data Exchange (ETDEWEB)

    Salatić, B. [University of Belgrade, Institute of Physics Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Petrović, S., E-mail: spetro@vinca.rs [University of Belgrade, Institute of Nuclear Science-Vinča, POB 522, 11001 Belgrade (Serbia); Peruško, D. [University of Belgrade, Institute of Nuclear Science-Vinča, POB 522, 11001 Belgrade (Serbia); Čekada, M.; Panjan, P. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Pantelić, D.; Jelenković, B. [University of Belgrade, Institute of Physics Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)

    2016-01-01

    Graphical abstract: - Highlights: • Experimental and numerical study of laser-induced ablation and micro-sized crater formation. • Dual-wavelength pulses induce creation of wider and deeper craters due to synergies of two processes. • Sunflower-like structure formed by dual-wavelength pulses at low irradiance. • Numerical model of nanosecond pulsed laser ablation for complex (Al/Ti)/Si system has been developed. - Abstract: The surface morphology of the ablation craters created in the multilayer 10×(Al/Ti)/Si system by nanosecond laser pulses at single- and dual wavelength has been studied experimentally and numerically. A complex multilayer thin film including ten (Al/Ti) bilayers deposited by ion sputtering on Si(1 0 0) substrate to a total thickness of 260 nm were illuminated at different laser irradiance in the range 0.25–3.5 × 10{sup 9} W cm{sup −2}. Single pulse laser irradiation was done at normal incidence in air, with the single wavelength, either at 532 nm or 1064 nm or with both laser light simultaneously in the ratio of 1:10 for energy per pulse between second harmonic and 1064 nm. Most of the absorbed laser energy was rapidly transformed into heat, producing intensive modifications of composition and morphology on the sample surface. The results show an increase in surface roughness, formation of specific nanostructures, appearance of hydrodynamic features and ablation of surface material with crater formation. Applying a small fraction (10%) of the second harmonic in dual-wavelength pulses, a modification of the 10×(Al/Ti)/Si system by a single laser pulse was reflected in the formation of wider and/or deeper craters. Numerical calculations show that the main physical mechanism in ablation process is normal evaporation without phase explosion. The calculated and experimental results agree relatively well for the whole irradiance range, what makes the model applicable to complex Al/Ti multilayer systems.

  5. Single Spatial-Mode Room-Temperature-Operated 3.0 to 3.4 micrometer Diode Lasers

    Science.gov (United States)

    Frez, Clifford F.; Soibel, Alexander; Belenky, Gregory; Shterengas, Leon; Kipshidze, Gela

    2010-01-01

    Compact, highly efficient, 3.0 to 3.4 m light emitters are in demand for spectroscopic analysis and identification of chemical substances (including methane and formaldehyde), infrared countermeasures technologies, and development of advanced infrared scene projectors. The need for these light emitters can be currently addressed either by bulky solid-state light emitters with limited power conversion efficiency, or cooled Interband Cascade (IC) semiconductor lasers. Researchers here have developed a breakthrough approach to fabrication of diode mid-IR lasers that have several advantages over IC lasers used for the Mars 2009 mission. This breakthrough is due to a novel design utilizing the strain-engineered quantum-well (QW) active region and quinternary barriers, and due to optimization of device material composition and growth conditions (growth temperatures and rates). However, in their present form, these GaSb-based laser diodes cannot be directly used as a part of sensor systems. The device spectrum is too broad to perform spectroscopic analysis of gas species, and operating currents and voltages are too high. In the current work, the emitters were fabricated as narrow-ridge waveguide index-guided lasers rather than broad stripe-gain guided multimode Fabry-Perot (FP) lasers as was done previously. These narrow-ridge waveguide mid-IR lasers exhibit much lower power consumptions, and can operate in a single spatial mode that is necessary for demonstration of single-mode distributed feedback (DBF) devices for spectroscopic applications. These lasers will enable a new generation of compact, tunable diode laser spectrometers with lower power consumption, reduced complexity, and significantly reduced development costs. These lasers can be used for the detection of HCN, C2H2, methane, and ethane.

  6. Characteristics of the Single-Longitudinal-Mode Planar-Waveguide External Cavity Diode Laser at 1064 nm

    Science.gov (United States)

    Numata, Kenji; Alalusi, Mazin; Stolpner, Lew; Margaritis, Georgios; Camp, Jordan; Krainak, Michael

    2014-01-01

    We describe the characteristics of the planar-waveguide external cavity diode laser (PW-ECL). To the best of our knowledge, it is the first butterfly-packaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. We evaluated its performance from the viewpoint of precision experiments. Using a hyperfine absorption line of iodine, we suppressed its frequency noise by a factor of up to 104 at 10 mHz. The PWECL's compactness and low cost make it a candidate to replace traditional Nd:YAG nonplanar ring oscillators and fiber lasers in applications that require a single longitudinal mode.

  7. Estimating single-tree branch biomass of Norway spruce by airborne laser scanning

    Science.gov (United States)

    Hauglin, Marius; Dibdiakova, Janka; Gobakken, Terje; Næsset, Erik

    2013-05-01

    The use of forest biomass for bioenergy purposes, directly or through refinement processes, has increased in the last decade. One example of such use is the utilization of logging residues. Branch biomass constitutes typically a considerable part of the logging residues, and should be quantified and included in future forest inventories. Airborne laser scanning (ALS) is widely used when collecting data for forest inventories, and even methods to derive information at the single-tree level has been described. Procedures for estimation of single-tree branch biomass of Norway spruce using features derived from ALS data are proposed in the present study. As field reference data the dry weight branch biomass of 50 trees were obtained through destructive sampling. Variables were further derived from the ALS echoes from each tree, including crown volume calculated from an interpolated crown surface constructed with a radial basis function. Spatial information derived from the pulse vectors were also incorporated when calculating the crown volume. Regression models with branch biomass as response variable were fit to the data, and the prediction accuracy assessed through a cross-validation procedure. Random forest regression models were compared to stepwise and simple linear least squares models. In the present study branch biomass was estimated with a higher accuracy by the best ALS-based models than by existing allometric biomass equations based on field measurements. An improved prediction accuracy was observed when incorporating information from the laser pulse vectors into the calculation of the crown volume variable, and a linear model with the crown volume as a single predictor gave the best overall results with a root mean square error of 35% in the validation.

  8. Multistabilities and symmetry-broken one-color and two-color states in closely coupled single-mode lasers

    Science.gov (United States)

    Clerkin, Eoin; O'Brien, Stephen; Amann, Andreas

    2014-03-01

    We theoretically investigate the dynamics of two mutually coupled, identical single-mode semi-conductor lasers. For small separation and large coupling between the lasers, symmetry-broken one-color states are shown to be stable. In this case the light outputs of the lasers have significantly different intensities while at the same time the lasers are locked to a single common frequency. For intermediate coupling we observe stable symmetry-broken two-color states, where both lasers lase simultaneously at two optical frequencies which are separated by up to 150 GHz. Using a five-dimensional model, we identify the bifurcation structure which is responsible for the appearance of symmetric and symmetry-broken one-color and two-color states. Several of these states give rise to multistabilities and therefore allow for the design of all-optical memory elements on the basis of two coupled single-mode lasers. The switching performance of selected designs of optical memory elements is studied numerically.

  9. Time resolved temperature measurement of polymer surface irradiated by mid-IR free electron laser

    Science.gov (United States)

    Araki, Mitsunori; Chiba, Tomoyuki; Oyama, Takahiro; Imai, Takayuki; Tsukiyama, Koichi

    2017-08-01

    We have developed the time-resolved temperature measurement system by using a radiation thermometer FLIR SC620. Temporal temperature profiles of an acrylic resin surface by the irradiation of infrared free electron laser (FEL) pulse were recorded in an 8 ms resolution to measure an instantaneous temperature rise and decay profile. Under the single-shot condition, a peak temperature defined as the temperature jump from the ambient temperature was found to be proportional to the absorbance. Under the multi-shot condition, the temperature accumulation was found to reach a roughly constant value where the supply and release of the heat is balanced.

  10. Over 19 W Single-Mode 1545 nm Er,Yb Codoped All-Fiber Laser

    Directory of Open Access Journals (Sweden)

    Jiadong Wu

    2017-01-01

    Full Text Available We report a high-power cladding-pumped Er,Yb codoped all-fiber laser with truly single transverse mode output. The fiber laser is designed to operate at 1545 nm by the use of a pair of fiber Bragg gratings (FBGs to lock and narrow the output spectrum, which can be very useful in generating the eye-safe ~1650 nm laser emission through the Stimulated Raman Scattering (SRS in silica fibers that is of interest in many applications. Two pieces of standard single-mode fibers are inserted into the laser cavity and output port to guarantee the truly single-mode output as well as good compatibility with other standard fiber components. We have obtained a maximum output power of 19.2 W at 1544.68 nm with a FWHM spectral width of 0.08 nm, corresponding to an average overall slope efficiency of 31.9% with respect to the launched pump power. This is, to the best of our knowledge, the highest output power reported from simple all-fiber single-mode Er,Yb codoped laser oscillator architecture.

  11. Single-mode, Rayleigh-Taylor growth-rate measurements on the OMEGA laser system

    International Nuclear Information System (INIS)

    Knauer, J. P.; Betti, R.; Bradley, D. K.; Boehly, T. R.; Collins, T. J. B.; Goncharov, V. N.; McKenty, P. W.; Meyerhofer, D. D.; Smalyuk, V. A.; Verdon, C. P.

    2000-01-01

    The results from a series of single-mode, Rayleigh-Taylor (RT) instability growth experiments performed on the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] using planar targets are reported. Planar targets with imposed mass perturbations were accelerated using five or six 351 nm laser beams overlapped with total intensities up to 2.5x10 14 W/cm 2 . Experiments were performed with both 3 ns ramp and 3 ns flat-topped temporal pulse shapes. The use of distributed phase plates and smoothing by spectral dispersion resulted in a laser-irradiation nonuniformity of 4%-7% over a 600 μm diam region defined by the 90% intensity contour. The temporal growth of the modulation in optical depth was measured using throughfoil radiography and was detected with an x-ray framing camera for CH targets. Two-dimensional (2-D) hydrodynamic simulations (ORCHID) [R. L. McCrory and C. P. Verdon, in Inertial Confinement Fusion (Editrice Compositori, Bologna, 1989), pp. 83-124] of the growth of 20, 31, and 60 μm wavelength perturbations were in good agreement with the experimental data when the experimental details, including noise, were included. The amplitude of the simulation optical depth is in good agreement with the experimental optical depth; therefore, great care must be taken when the growth rates are compared to dispersion formulas. Since the foil's initial condition just before it is accelerated is not that of a uniformly compressed foil, the optical density measurement does not accurately reflect the amplitude of the ablation surface but is affected by the initial nonuniform density profile. (c) 2000 American Institute of Physics

  12. Laser ion source with solenoid field

    International Nuclear Information System (INIS)

    Kanesue, Takeshi; Okamura, Masahiro; Fuwa, Yasuhiro; Kondo, Kotaro

    2014-01-01

    Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. The laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 10 11 , which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator

  13. Laser ion source with solenoid field

    Science.gov (United States)

    Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; Okamura, Masahiro

    2014-11-01

    Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. The laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 1011, which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.

  14. SunShot Initiative Portfolio Book 2014

    Energy Technology Data Exchange (ETDEWEB)

    Solar Energy Technologies Office

    2014-05-01

    The 2014 SunShot Initiative Portfolio Book outlines the progress towards the goals outlined in the SunShot Vision Study. Contents include overviews of each of SunShot’s five subprogram areas, as well as a description of every active project in the SunShot’s project portfolio as of May 2014.

  15. Comparison of high power large mode area and single mode 1908nm Tm-doped fiber lasers

    Science.gov (United States)

    Johnson, Benjamin R.; Creeden, Daniel; Limongelli, Julia; Pretorius, Herman; Blanchard, Jon; Setzler, Scott D.

    2016-03-01

    We compare large mode area (LMA) and single-mode (SM) double-clad fiber geometries for use in high power 1908nm fiber lasers. With a simple end-pumped architecture, we have generated 100W of 1908nm power with LMA fiber at 40% optical efficiency and 117W at 52.2% optical efficiency with single-mode fiber. We show the LMA fiber is capable of generating >200W and the SM fiber is capable of >300W at 1908nm. In all cases, the fiber lasers are monolithic power-oscillators with no free-space coupling.

  16. Single mode operation in a pulsed Ti:sapphire laser oscillator with a grazing-incidence four-mirror cavity

    CERN Document Server

    Ko, D K; Binks, D J; Gloster, L A W; King, T A

    1998-01-01

    We demonstrate stable single mode operation in a pulsed Ti:sapphire laser oscillator with a novel grazing-incidence four-mirror coupled cavity. This cavity consists of a grating, a gain medium, and four mirrors and, therefore, has a four-arm interferometer configuration. Through the interferometric effect, we could suppress the adjacent modes and obtain stable single mode operation with a bandwidth of < 200 MHz. We also have developed a general analysis of the laser modes and the threshold conditions for configuration and the experimental results agree well with the theoretical predictions.

  17. Achievable debris orbit prediction accuracy using laser ranging data from a single station

    Science.gov (United States)

    Sang, Jizhang; Bennett, James C.

    2014-07-01

    Earlier studies have shown that an orbit prediction accuracy of 20 arc sec ground station pointing error for 1-2 day predictions was achievable for low Earth orbit (LEO) debris using two passes of debris laser ranging (DLR) data from a single station, separated by about 24 h. The accuracy was determined by comparing the predicted orbits with subsequent tracking data from the same station. This accuracy statement might be over-optimistic for other parts of orbit far away from the station. This paper presents the achievable orbit prediction accuracy using satellite laser ranging (SLR) data of Starlette and Larets under a similar data scenario as that of DLR. The SLR data is corrupted with random errors of 1 m standard deviation so that its accuracy is similar to that of DLR data. The accurate ILRS Consolidated Prediction Format orbits are used as reference to compute the orbit prediction errors. The study demonstrates that accuracy of 20 arc sec for 1-2 day predictions is achievable.

  18. Laser-guidance-based cell deposition microscope for heterotypic single-cell micropatterning

    Energy Technology Data Exchange (ETDEWEB)

    Ma Zhen; Wan Qin; Yun, Julie X; Gao, Bruce Z [Department of Bioengineering, COMSET, Clemson University, Clemson, SC 29634 (United States); Pirlo, Russell K [Naval Research Laboratory, Washington, DC 20375 (United States); Yuan, Xiaocong [Institute of Modern Optics, Key Laboratory of Optoelectronic Information Science and Technology, Ministry of Education of China, Nankai University, Tianjin (China); Xiang Peng [Institute of Optoelectronics, Shenzhen University, Shenzhen, Guangdong (China); Borg, Thomas K, E-mail: zgao@clemson.edu [Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC (United States)

    2011-09-15

    Cell patterning methods enable researchers to control specific homotypic and heterotypic contact-mediated cell-cell and cell-ECM interactions and to impose defined cell and tissue geometries. To micropattern individual cells to specific points on a substrate with high spatial resolution, we have developed a cell deposition microscope based on the laser-guidance technique. We discuss the theory of optical forces for generating laser guidance and the optimization of the optical configuration (NA {approx} 0.1) to manipulate cells with high speed in three dimensions. Our cell deposition microscope is capable of patterning different cell types onto and within standard cell research devices and providing on-stage incubation for long-term cell culturing. Using this cell deposition microscope, rat mesenchymal stem cells from bone marrow were micropatterned with cardiomyocytes into a substrate microfabricated with polydimethylsiloxane on a 22 mm x 22 mm coverglass to form a single-cell coculturing microenvironment, and their electrophysiological property changes were investigated during the coculturing days.

  19. Analysis and differentiation of mineral dust by single particle laser mass spectrometry

    International Nuclear Information System (INIS)

    Gallavardin, S. J.; Lohmann, U.; Cziczo, Daniel J.

    2008-01-01

    This study evaluates the potential of single particle laser desorption/ionization mass spectrometry for the analysis of atmospherically relevant mineral dusts. Samples of hematite, goethite, calcium carbonate, calcium sulfate, silica, quartz, montmorrillonite, kaolinite, illite, hectorite, wollastonite and nephelinsyenit were investigated in positive and negative ion mode with a monopolar time-of-flight mass spectrometer where the desorption/ionization step was performed with a 193 nm excimer laser (∼10 9 W/cm 2 ). Particle size ranged from 500 nm to 3 (micro)m. Positive mass spectra mainly provide elemental composition whereas negative ion spectra provide information on element speciation and of a structural nature. The iron oxide, calcium-rich and aluminosilicate nature of particles is established in positive ion mode. The differentiation of calcium materials strongly relies on the calcium counter-ions in negative mass spectra. Aluminosilicates can be differentiated in both positive and negative ion mode using the relative abundance of various aluminum and silicon ions

  20. Semiclassical dye-laser equations and the unidirectional single-frequency operation

    Science.gov (United States)

    Fu, Hong; Haken, H.

    1987-11-01

    A semiclassical description for dye lasers is proposed, where the energy-level diagram of the dye molecule is assumed to consist of a continuous bandlike ground state and an excited singlet state. Unidirectional single-frequency (s.f.) operation is discussed. The linear-stability analysis for this operation reveals a very low threshold instability, which may appear generally in practical lasers. The ratio of the instability threshold to the lasing threshold may be of any value greater than 1, depending mainly on the bandwidth and the distribution of the dipole moments on the band, but it is independent of the cavity loss. This instability may account for that observed in recent experiments by Hillman, Krasinki, Boyd, and Stroud [Phys. Rev. Lett. 52, 1605 (1984)]. A general approach to analyzing the linear stability of the s.f. operation of the Maxwell-Bloch equations is also proposed, which states that only the eigenvalues of a 2×2 matrix are relevant: one concerns the stability of the s.f. operation near the lasing threshold, the other determines the instability threshold of this operation.