WorldWideScience

Sample records for beam laser spectroscopy

  1. Laser spectroscopy on the heavy ion beams

    International Nuclear Information System (INIS)

    In the presented report the perspectives of the study of the electric charge and current space distributions in the nuclei by laser spectroscopy methods on the beams of the fast multiple charged ions are discussed. The calculations of both the level energies and widths in the H-like and He-like ions and of the isotopic shifts and hyperfine splitting in the optical spectra of these ions are performed. The project of the experimental set-up for these measurements is considered. (author)

  2. Infrared laser spectroscopy of molecular beams

    International Nuclear Information System (INIS)

    Presents the first successful observation of the infrared spectrum of a single, collimated (3.6 x 10-4 steradians) beam of carbon monoxide molecules sampled from a supersonic free jet expansion. The principle of the technique is to detect directly the power absorbed from a tunable infrared laser beam by the molecules of a molecular beam, using a microcalorimeter (a cyrogenic bolometer) placed a short distance downstream from the intersection of the two beams. Since infrared fluorescent lifetimes are long, the absorbed power is transferred by the molecules to the bolometer where it is detected as a change in resistance. (Auth.)

  3. Laser spectroscopy in an lithium beam

    International Nuclear Information System (INIS)

    Full text: The absorption and fluorescence spectra were measured in a collimated and non-collimated atomic lithium beam by means of a diode laser. Spectral lines with a similar linewidth as the lines observed before in a stationary lithium vapor were observed in the non-collimated beam. The spatial structure of the gas region which emits fluorescence permits to observe in situ the hyperfine levels of lithium atoms: each level corresponds to a relatively plane and well defined region. This indicates that the atoms leave the oven following straight lines (otherwise the collisions would produce diffuse regions), which is in correspondence to the high values of the free mean path expected for the gas at this density, and the extension of the shadow left at the condensation plate. In the collimated beam (diameter D=1 mm, and divergence of 90 mrad), the absorption spectra has a width of 450 MHz (12 deg K or less), which permits the measurement of the hyperfine structure. In this case, from the absorption data we obtained ρD=2 x 1014 atoms/m2. The temperature obtained from the Doppler width is consistent with the temperature obtained from the beam geometry. The lithium atom flow was measured with a quartz thickness monitor and based on estimates of the initial oven temperature and density measurements. Fluorescence measurements have better sensitivity ab do not present problems in the base line due to etalon effects. It is possible to observe the detail structure of the side wings in the line spectra

  4. On-line laser spectroscopy with thermal atomic beams

    CERN Document Server

    Thibault, C; De Saint-Simon, M; Duong, H T; Guimbal, P; Huber, G; Jacquinot, P; Juncar, P; Klapisch, Robert; Liberman, S; Pesnelle, A; Pillet, P; Pinard, J; Serre, J M; Touchard, F; Vialle, J L

    1981-01-01

    On-line high resolution laser spectroscopy experiments have been performed in which the light from a CW tunable dye laser interacts at right angles with a thermal atomic beam. /sup 76-98/Rb, /sup 118-145 /Cs and /sup 208-213/Fr have been studied using the ionic beam delivered by the ISOLDE on-line mass separator at CERN while /sup 30-31/Na and /sup 38-47/K have been studied by setting the apparatus directly on-line with the PS 20 GeV proton beam. The principle of the method is briefly explained and some results concerning nuclear structure are given. The hyperfine structure, spins and isotope shifts of the alkali isotopes and isomers are measured. (8 refs).

  5. Atomic lifetime measurements by beam-gas-dye laser spectroscopy

    Science.gov (United States)

    Schmoranzer, H.; Volz, U.

    1993-01-01

    Beam-gas-dye laser spectroscopy as a precise, cascade-free and collision-free method for measuring atomic lifetimes and individual oscillator strengths is described. Its recent application to fine-structure levels of the KrI 5p configuration is reported. The experimental uncertainty is reduced by one order of magnitude, with respect to previous work, down to 0.3% (1σ). The discussion of these results in comparison with experimental and theoretical ones from the literature underlines the precision of the method and its potential to guide future theoretical developments.

  6. Multiphoton Ionization Detection in Collinear Laser Spectroscopy of Isolde Beams

    CERN Multimedia

    2002-01-01

    The experiments using the multiphoton ionization technique have been continued in the beginning of 1990 with stable beam tests on the modified apparatus and with another radioactive beam time on Yb. Higher laser power and an increased vacuum in the ionization region (see figure) yielded a further gain in sensitivity, mainly due to the better suppression of the background ions produced in rest gas collisions. For even Yb isotopes we have now reached a detection efficiency of $\\epsilon$~=~1~x~10$^{-5}$ ions per incoming atom at a background count rate of 30~ions from a beam of 5~x~10$^9$. This sensitivity was high enough for spectroscopy on $^{157}$Yb, where the typical ISOLDE yield of 5~x~10$^7$Yb ions is covered by an isobaric contamination of more than 10$^{10}$ ions. Measurements have also been performed on $^{175}$Yb. These give the first precise value for the magnetic moment of this isotope, $\\mu$~=~0.766(8)$ mu _{N} $, which agrees rather well with the magnetic moment of the isotone $^{177}$Hf. The isoto...

  7. Laser assisted decay spectroscopy at the CRIS beam line at ISOLDE

    International Nuclear Information System (INIS)

    A new collinear resonant ionization spectroscopy (CRIS) beam line has recently been installed at ISOLDE, CERN utilising lasers to combine collinear laser spectroscopy and resonant ionization spectroscopy. The combined technique offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing sensitive secondary experiments to be performed. A new programme aiming to use the CRIS technique for the separation of nuclear isomeric states for decay spectroscopy will commence in 2011. A decay spectroscopy station, consisting of a rotating wheel implantation system for alpha decay spectroscopy, and three high purity germanium detectors around the implantation site for gamma-ray detection, has been developed for this purpose. This paper will report the current status of the laser assisted decay spectroscopy set-up for the CRIS beam line.

  8. Laser spectroscopy of atomic beams of short-lived nuclei

    International Nuclear Information System (INIS)

    A possibility of performing laser-nuclear-spectroscopic experiments at qualitatively new level aimed to solve the second-glass current problem and to search T-non invariant effects in the beta-decay of atomic nuclei is discussed. The question of the increase in efficiency of the experiments, aimed to study the main characteristics of nuclei, far from the beta-stability, by means of the laser spectroscopy methods is considered. 147 refs.; 5 figs.; 1 tab

  9. Laser assisted decay spectroscopy at the CRIS beam line at ISOLDE

    International Nuclear Information System (INIS)

    The new collinear resonant ionization spectroscopy (Cris) experiment at Isolde, Cern uses laser radiation to stepwise excite and ionize an atomic beam for the purpose of ultra-sensitive detection of rare isotopes and hyperfine structure measurements. The technique also offers the ability to purify an ion beam that is contaminated with radioactive isobars, including the ground state of an isotope from its isomer. A new program using the Cris technique to select only nuclear isomeric states for decay spectroscopy commenced last year. The isomeric ion beam is selected using a resonance within its hyperfine structure and subsequently deflected to a decay spectroscopy station. This consists of a rotating wheel implantation system for alpha and beta decay spectroscopy, and up to three high purity germanium detectors for gamma-ray detection. This paper gives an introduction to the Cris technique, the current status of the laser assisted decay spectroscopy set-up and recent results from the experiment in November 2011.

  10. X-ray laser spectroscopy with an electron beam ion trap at the free electron laser LCLS

    International Nuclear Information System (INIS)

    We present a first laser spectroscopy experiment in the keV energy regime, performed at the Free-Electron Laser LCLS at Stanford. An electron beam ion trap was used to provide a target of highly charged O, F and Fe ions. The resonant fluorescence spectra obtained for various transitions were calibrated to simultaneously measured Lyman lines of hydrogenic ions.

  11. Part I: $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy

    CERN Document Server

    Andreyev, Andrei

    2013-01-01

    Part I: $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy

  12. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  13. $\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

    CERN Multimedia

    We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

  14. Measurement of Moments and Radii of Light Nuclei by Collinear Fast-Beam Laser Spectroscopy and $\\beta$-NMR Spectroscopy

    CERN Multimedia

    Marinova, K P

    2002-01-01

    Nuclear Moments and radii of light unstable isotopes are investigated by applying different high-sensitivity and high-resolution techniques based on collinear fast-beam laser spectroscopy. A study of nuclear structure in the sd shell is performed on neon isotopes in the extended chain of $^{17-28}$Ne, in particular on the proton-halo candidate $^{17}$Ne. Measurements of hyperfine structure and isotope shift have become possible by introducing an ultra-sensitive non-optical detection method which is based on optical pumping, state-selective collisional ionization and $\\beta$-activity counting. The small effect of nuclear radii on the optical isotope shifts of light elements requires very accurate measurements. The errors are dominated by uncertainties of the Doppler shifts which are conventionally determined from precisely measured acceleration voltages. These uncertainties are removed by measuring the beam energy with simultaneous excitation of two optical lines in parallel / antiparallel beam configuration. ...

  15. A trap-based pulsed positron beam optimised for positronium laser spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B. S., E-mail: ben.cooper.13@ucl.ac.uk; Alonso, A. M.; Deller, A.; Wall, T. E.; Cassidy, D. B. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-10-15

    We describe a pulsed positron beam that is optimised for positronium (Ps) laser-spectroscopy experiments. The system is based on a two-stage Surko-type buffer gas trap that produces 4 ns wide pulses containing up to 5 × 10{sup 5} positrons at a rate of 0.5-10 Hz. By implanting positrons from the trap into a suitable target material, a dilute positronium gas with an initial density of the order of 10{sup 7} cm{sup −3} is created in vacuum. This is then probed with pulsed (ns) laser systems, where various Ps-laser interactions have been observed via changes in Ps annihilation rates using a fast gamma ray detector. We demonstrate the capabilities of the apparatus and detection methodology via the observation of Rydberg positronium atoms with principal quantum numbers ranging from 11 to 22 and the Stark broadening of the n = 2 → 11 transition in electric fields.

  16. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  17. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  18. Two-step resonance ionization spectroscopy of Na atomic beam using cw and pulsed lasers

    International Nuclear Information System (INIS)

    Two-step photoionization of sodium atomic beam has been carried out using a cw and a pulsed dye lasers. Sodium ions have been detected by a time of flight method in order to reduce background noise. With a proper power of the pulsed dye laser the sodium atomic beam has been irradiated by a resonant cw dye laser. The density of the sodium atomic beam is estimated to be 103 cm-3 at the ionization area. (author)

  19. Universal Slow RI-Beam Facility at RIKEN RIBF for Laser Spectroscopy of Short-Lived Nuclei

    International Nuclear Information System (INIS)

    A universal slow RI-beam facility (SLOWRI) for precision atomic spectroscopy is being built at the RIKEN RI-beam factory. The facility will provide a wide variety of low-energy nuclear ions of all elements produced by projectile fragmentation of high-energy heavy-ion beams and thermalized by an RF-carpet ion guide. At prototype SLOWRI, radioactive Be isotope ions produced at 1 GeV were decelerated and cooled in an ion trap down to 1 μeV by employing laser cooling. The ground state hyperfine structures of 7Be+ and 11Be+ were measured accurately by laser microwave double resonance spectroscopy. Measurements of the S1/2→P1/2, P3/2 transition frequencies of 7,9,10,11Be+ ions are also in progress aiming at the study of the nuclear charge radii. Other possible experiment at SLOWRI, such as mass spectroscopy, are also discussed.

  20. Nuclear structure of light thallium isotopes as deduced from laser spectroscopy on a fast atom beam

    International Nuclear Information System (INIS)

    After optimizing the system by experiments on /sup 201,203,205/Tl, the neutron-deficient isotopes 189-193Tl have been studied using the collinear fast atom beam laser spectroscopy system at UNISOR on-line to the Holifield Heavy Ion Research Facility. A sensitive system for the measurements was developed since the light isotopes were available in mass-separated beams of only 7 x 104 to 4 x 105 atoms per second. By laser excitation of the 535 nm atomic transitions of atoms in the beam, the 6s27s 2S/sub 1/2/ and 6s26s 2P/sub 3/2/ hyperfine structures were measured, as were the isotope shifts of the 535 nm transitions. From these, the magnetic dipole moments, spectroscopic quadrupole moments and isotopic changes in mean-square charge radius were deduced. The magnetic dipole moments are consistent with previous data. The /sup 190,192/Tl isotopes show a considerable difference in quadrupole deformations as well as an anomalous isotope shift with respect to 194Tl. A large isomer shift in 193Tl is observed implying a larger deformation in the 9/2- isomer than in the 1/2+ ground state. The /sup 189,191,193/Tl isomers show increasing deformation away from stability. A deformed shell model calculation indicates that this increase in deformation can account for the dropping of the 9/2- band in these isotopes while an increase in neutron pairing correlations, having opposite and compensating effects on the rotational moment of inertia, maintains the 9/2- strong-coupled band structure. 105 refs., 27 figs

  1. Parameters Optimization of Laser-Induced Breakdown Spectroscopy Experimental Setup for the Case with Beam Expander

    Science.gov (United States)

    Wang, Xin; Zhang, Lei; Fan, Juanjuan; Li, Yufang; Gong, Yao; Dong, Lei; Ma, Weiguang; Yin, Wangbao; Jia, Suotang

    2015-11-01

    Improvement of measurement precision and repeatability is one of the issues currently faced by the laser-induced breakdown spectroscopy (LIBS) technique, which is expected to be capable of precise and accurate quantitative analysis. It was found that there was great potential to improve the signal quality and repeatability by reducing the laser beam divergence angle using a suitable beam expander (BE). In the present work, the influences of several experimental parameters for the case with BE are studied in order to optimize the analytical performances: the signal to noise ratio (SNR) and the relative standard deviation (RSD). We demonstrate that by selecting the optimal experimental parameters, the BE-included LIBS setup can give higher SNR and lower RSD values of the line intensity normalized by the whole spectrum area. For validation purposes, support vector machine (SVM) regression combined with principal component analysis (PCA) was used to establish a calibration model to realize the quantitative analysis of the ash content. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The measurement accuracy presented here for ash content analysis is estimated to be 0.31%, while the average relative error is 2.36%. supported by the 973 Program of China (No. 2012CB921603), National Natural Science Foundation of China (Nos. 61475093, 61127017, 61178009, 61108030, 61378047, 61275213, 61475093, and 61205216), the National Key Technology R&D Program of China (No. 2013BAC14B01), the Shanxi Natural Science Foundation (Nos. 2013021004-1 and 2012021022-1), the Shanxi Scholarship Council of China (Nos. 2013-011 and 2013-01), and the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi, China

  2. Beam-line systems for pump-probe photoelectron spectroscopy using SR and laser

    CERN Document Server

    Kamada, M; Takahashi, K; Doi, Y I; Fukui, K; Kinoshita, T; Haruyama, Y; Asaka, S; Fujii, Y; Itoh, M

    2001-01-01

    Combined systems for photoelectron spectroscopy using synchrotron radiation (SR) and laser have been constructed at BL5A and BL6A2 in the UVSOR facility, Okazaki. The systems consist of photoelectron spectrometers with high performance, mode-locked lasers, and timing electronic circuits. The laser pulses with repetition frequency of 90 MHz are synchronized with the SR pulses. An upgrade project to install a micro-ESCA at BL6A2, which is now in progress, is also reported.

  3. Photon detection system for laser spectroscopy experiments with cooled/bunched beams at BECOLA facility at NSCL

    Science.gov (United States)

    Hughes, Maximilian; Minamisono, Kei; Mantica, Paul; Rossi, Dominic; Ryder, Caleb; Klose, Andrew; Tarazona, David; Strum, Ryan; Bollen, Georg; Ringle, Ryan; Barquest, Brad; Geppert, Christopher

    2013-10-01

    The BEam COoler and LAser spectroscopy (BECOLA) facility at NSCL is designed to determine fundamental properties of the atomic nucleus such as the charge radii, the spin and electromagnetic moments. Commissioning tests of BECOLA has been completed using a stable 39K beam produced from an offline ion source. The 39K beam was cooled and bunched and propagated collinearly with laser light. The resulting fluorescence was detected in a photomultiplier tube (PMT)sensitive to the wavelength of D1 transition of 39K The PMT was cooled to minimize background due to dark counts. The resulting fluorescence light was measured as a function of laser frequency and time relative to the 39K beam bunch. An EPICS-based Control Systems Studio (CSS) was used for data acquisition and the software package Root was used for data analysis. The performance characteristics of the photon detection system as well as the laser spectroscopy of bunched 39K will be discussed. Work was supported in part by the National Science Foundation, Grant PHY-11-02511.

  4. Nuclear Ground State Properties in Strontium by Fast Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    Hyperfine structures and isotope shifts of strontium isotopes with A=78 to A=100 were measured by collinear fast beam laser spectroscopy. Nuclear spins, moments and changes in mean square charge radii are extracted from the data. The spins and moments of most of the odd isotopes are explained in the framework of the single particle model. The changes in mean square charge radii show a decrease with increasing neutron number below the N=50 shell closure. Above N=50 the charge radii increase regularly up to N=59 before revealing a strong discontinuity, indicating the onset of strong ground state deformation. A comparison of the droplet model shows that for the transitional isotopes below and above N=50, the zero point quadrupole motion describes part of the observed shell effect. Calculations carried out in the Hartree-Fock plus BCS model suggest an additional change in the surface region of the charge distribution at spherical shape. From these calculations it is furthermore proposed, that the isotopes $^7

  5. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF +

    Science.gov (United States)

    Coe, J. V.; Owrutsky, J. C.; Keim, E. R.; Agman, N. V.; Hovde, D. C.; Saykally, R. J.

    1989-04-01

    We report the development of a new general technique for measuring vibration-rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration-rotation transitions of HF+ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v=0 and v=1 in the X 2Π state. Comparisons with many-body perturbation theory results are presented.

  6. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF/sup +/

    Energy Technology Data Exchange (ETDEWEB)

    Coe, J.V.; Owrutsky, J.C.; Keim, E.R.; Agman, N.V.; Hovde, D.C.; Saykally, R.J.

    1989-04-15

    We report the development of a new general technique for measuring vibration--rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration--rotation transitions of HF/sup +/ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v = 0 and v = 1 in the X /sup 2/Pi state. Comparisons with many-body perturbation theory results are presented.

  7. Sub-Doppler direct infrared laser absorption spectroscopy in fast ion beams: The fluorine hyperfine structure of HF+

    International Nuclear Information System (INIS)

    We report the development of a new general technique for measuring vibration--rotation spectra of molecular ions with sub-Doppler resolution and with accurate determination of the mass and number density of the carriers of all spectral features. With this method, called direct laser absorption spectroscopy in fast ion beams (DLASFIB), we have carried out the first observation of direct absorption of photons by ions in a fast ion beam. Hyperfine-resolved vibration--rotation transitions of HF+ have been measured, and along with optical combination differences and laser magnetic resonance data, have been analyzed to yield the fluorine hyperfine parameters a, b, c and d for both v = 0 and v = 1 in the X 2Pi state. Comparisons with many-body perturbation theory results are presented

  8. Study of Nuclear Moments and Mean Square Charge Radii by Collinear Fast-Beam Laser Spectroscopy

    CERN Multimedia

    2002-01-01

    The collinear fast-beam laser technique is used to measure atomic hyperfine structures and isotope shifts of unstable nuclides produced at ISOLDE. This gives access to basic nuclear ground-state and isomeric-state properties such as spins, magnetic dipole and electric quadrupole moments, and the variation of the nuclear mean square charge radius within a sequence of isotopes. \\\\ \\\\ Among the various techniques used for this purpose, the present approach is of greatest versatility, due to the direct use of the beams from the isotope separator. Their phase-space properties are exploited to achieve high sensitivity and resolution. The optical spectra of neutral atoms are made accessible by converting the ion beams into fast atomic beams. This is accomplished in the charge-exchange cell which is kept at variable potential ($\\pm$10~kV) for Doppler-tuning of the effective laser wavelength. The basic optical resolution of 10$^{-8}$ requires a 10$^{-5}$ stability of the 60~kV main acceleration voltage and low energy ...

  9. Automatic laser beam alignment using blob detection for an environment monitoring spectroscopy

    Science.gov (United States)

    Khidir, Jarjees; Chen, Youhua; Anderson, Gary

    2013-05-01

    This paper describes a fully automated system to align an infra-red laser beam with a small retro-reflector over a wide range of distances. The component development and test were especially used for an open-path spectrometer gas detection system. Using blob detection under OpenCV library, an automatic alignment algorithm was designed to achieve fast and accurate target detection in a complex background environment. Test results are presented to show that the proposed algorithm has been successfully applied to various target distances and environment conditions.

  10. Welding by laser beam

    International Nuclear Information System (INIS)

    A laser which does not require a vacuum and the beam from which can be projected over a distance without loss of power is sited outside a welding zone and the beam projected through a replaceable laser transparent window. The window is designed and shaped to facilitate access of the beam of workpiece items to be welded in containment. Either the workpiece or the laser beam may be moved during welding. (author)

  11. Active Beam Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R. J. E.; Biel, W.; Marchuk, O.; Summers, H. P.; Whiteford, A.; Giroud, C.; Hawkes, N. C.; Zastrow, K. D.

    2008-03-01

    Charge eXchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package CHEAP", and finally "Forward Prediction of Spectral Features" are described. Beam Emission Spectroscopy (BES) is proposed as indispensable cross-calibration tool for absolute local impurity density measurements and also for the continuous monitoring of the neutral beam power deposition profile. Finally, a full exploitation of the `Motional Stark Effect' pattern is proposed to deduce local pitch angles, total magnetic fields and possibly radial electric fields. For the proposed active beam spectroscopy diagnostic on ITER comprehensive performance studies have been carried out. Estimates of expected spectral signal-to-noise ratios are based on atomic modelling of neutral beam stopping and emissivities for CXRS, BES and background continuum radiation as well as extrapolations from present CXRS diagnostic systems on JET, Tore Supra, TEXTOR and ASDEX-UG. Supplementary to thermal features a further promising application of CXRS has been proposed recently for ITER, that is a study of slowing-down alpha particles in the energy range up to 2 MeV making use of the 100 keV/amu DNB (Diagnostic Neutral Beam) and the 500 keV/amu HNB (Heating Neutral Beam). Synthetic Fast Ion Slowing-Down spectra are evaluated in terms of source rates and slowing-down parameters

  12. Nuclear moments and isotopic variation of the mean square charge radii of strontium nuclei by atomic beam laser spectroscopy

    International Nuclear Information System (INIS)

    Hyperfine structure and optical isotope shift measurements have been performed on a series of stable and radioactive strontium isotopes (A = 80 to 90), including two isomers 85m and 87m. The spectroscopy applied continuous wave dye laser induced fluorescence of free atoms at λ=293.2 nm in a well collimated atomic beam. The 293.2 nm ultraviolet light was generated by frequency doubling the output of a dye laser in either a temperature tuned Ammonium Dihydrogen Arsenate (ADA) crystal or an angle tuned Lithium Iodate crystal. A special radio frequency (rf) technique was used to tune the dye laser frequency with long term stability. Radioactive Sr isotopes were produced either by neutron capture of stable strontium or by (α,xn) reactions from krypton gas. The samples were purified by an electromagnetic mass separator and their sizes were of order 100 pg, which corresponds to 1011 atoms. The observed results of the hyperfine structure components are evaluated in terms of nuclear magnetic dipole moments and electric quadrupole moments. Changes in mean square charge radii of strontium nuclei which were extracted from the isotope shift measurements, exhibit a distinct shell effect at the neutron magic number N=50. The experimental data are analysed and compared with some theoretical nuclear model predictions. The strong increase of the nuclear charge radii with decreasing neutron number of isotopes below N=50 is in agreement with the variation of the mean square deformation extracted from measured B(E2) values. (orig.)

  13. Semiconductor laser beam bending

    OpenAIRE

    YILDIRIM, REMZİ; ÇELEBİ, FATİH VEHBİ

    2015-01-01

    This study is about a single-component cylindrical structured lens with a gradient curve that was used for bending laser beams. It operates under atmospheric conditions and bends the laser beam independently of temperature, pressure, polarity, polarization, magnetic field, electric field, radioactivity, and gravity. A single-piece cylindrical lens that can bend laser beams was developed. Lenses are made of transparent, tinted, or colored glass and are used to undermine or absorb the energy of...

  14. Laser-Beam Separator

    Science.gov (United States)

    Mcdermid, I. S.

    1984-01-01

    Train of prisms and optical stop separate fundamental beam of laser from second and higher order harmonics of beam produced in certain crystals and by stimulated Raman scattering in gases and liquids.

  15. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove;

    2007-01-01

    The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  16. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  17. Investigation of hyperfine structures of spectral lines of singly ionized praseodymium using fourier transform spectrum, saturation spectroscopy and collinear laser ion beam spectroscopy

    International Nuclear Information System (INIS)

    The hyperfine (hf) structure splitting of a fine structure energy level is caused by the interaction of the electromagnetic nuclear moments with the electromagnetic moments of the electron shell. The splitting of the hf structure is determined by the magnetic dipole interaction constant A and an additional small shift in the hf levels is determined by the quadrupole interaction constant B. Praseodymium (Pr) has five electrons in the outermost shells. The coupling of five (Pr I) or four (Pr II) electrons produces a large number of fine structure levels resulting in a dense and complicated optical spectrum. For the classification of spectral lines, precise values of hf constants and energy values of the levels involved in the transitions are required. This work is divided into three parts: In the first part, the spectral lines of Pr II are analyzed using a high resolution Fourier transform spectrum in the spectral range from 3260 to 11700 Å. Transition wavelengths of Pr II spectral lines are re-determined and then, using these accurate transition wavelengths, the energy values of the levels involved in the transitions are improved. Wavelengths for 477 spectral lines and energy values for 227 known levels of Pr II are improved. Investigation of narrow hf structures needs a reduction of the Doppler broadening of the investigated lines. The hf structures are experimentally investigated using two methods of Doppler reduced spectroscopy. In the second part of this work, the hf structures of the Pr II spectral lines are investigated in a hollow cathode discharge lamp using inter-modulated laser induced fluorescence spectroscopy. Using this method 6 Pr II transitions are investigated and a spectral width of about ca. 200 MHz was achieved. The main research work is carried out in the third part. The Pr II spectral lines are investigated using the high resolution method of Collinear Laser Ion Beam Spectroscopy (CLIBS). The CLIBS measurements are performed using the Marburg

  18. Observation of conformers with laser electronic spectroscopy in supersonic molecular beams

    Science.gov (United States)

    Philis, John G.; Kosmidis, Constantine E.; Tsekeris, Pericles

    1998-07-01

    We discuss the ability and effectiveness of electronic spectroscopy to reveal rotational isomerism by presenting some examples of the S1 implied by S0 electronic spectra of non-rigid molecules. One or two photon electronic spectra have multiple features when the molecule has more than one conformational preference. Torsional bands showing up in the spectrum complicate the assignment of conformers. Hole burning experiments give definite conclusions on the existence of rotational isomerism and an example from the literature is given.

  19. Photoelectron photoion molecular beam spectroscopy

    International Nuclear Information System (INIS)

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed

  20. Femtosecond laser spectroscopy

    CERN Document Server

    Hannaford, Peter

    2005-01-01

    As concepts and methodologies have evolved over the past two decades, the realm of ultrafast science has become vast and exciting and has impacted many areas of chemistry, biology and physics, and other fields such as materials science, electrical engineering, and optical communication. The field has recently exploded with the announcement of a series of remarkable new developments and advances. This volume surveys this recent growth in eleven chapters written by leading international researchers in the field. It includes sections on femtosecond optical frequency combs, soft x-ray femtosecond laser sources, and attosecond laser sources. In addition, the contributors address real-time spectroscopy of molecular vibrations with sub-5-fs pulses and multidimensional femtosecond coherent spectroscopies for studying molecular and electron dynamics. Novel methods for measuring and characterizing ultrashort laser pulses and ultrashort pulses of light are also described. The topics covered are revolutionizing the field...

  1. Dual-beam, second-derivative tunable diode-laser infrared spectroscopy applied to trace-gas measurement

    International Nuclear Information System (INIS)

    A dual beam diode laser spectrometer has been constructed using off-axis reflective optics. The spectrometer can be amplitude modulated for direct absorption measurements or frequency modulated to obtain derivative spectra. The spectrometer has high throughput, is easy to operate and align, provides good dual beam compensation, and has no evidence of the interference effects that have been observed in diode laser spectrometers using refractive optics. Unpurged, using second derivative techniques, the instrument has measured 108 parts-per-million CO (10 cm absorption cell, atmospheric pressure-broadened) with good signal/noise. With the replacement of marginal instrumental components, the signal/noise should be substantially increased. This instrument was developed to monitor the evolution of decomposition gases in sealed containers of small volume at atmospheric pressure

  2. Laser ionization mass spectroscopy

    Science.gov (United States)

    Bernardez, Luis J., III; Siekhaus, W. J.

    1989-10-01

    Laser Ionization Mass Spectroscopy (LIMS) is a simple technique with several advantages and disadvantages over standard mass spectroscopy techniques. The LIMS technique uses a laser to vaporize a small portion of a sample. The vapor from the sample consists of a mixture of charged and neutral atoms or fragments. Using electrostatic grids, the ions (positive or negative) are given a known amount of kinetic energy and sent down a time-of-flight tube. The time it takes the ions to travel down the flight tube is recorded. Knowing the ions' energy, the length of the flight tube, and the time it takes the ions to travel that distance, the masses of the ions can be calculated. The instrument used is a LIMA 3 made by Cambridge Mass Spectrometry. It has a Quanta Ray DCR-11 Nd:YAG laser, which was frequency-quadrupled to 266 nm. The laser spot size is typically between 2 and 5 microns in diameter and the pulse width is between 5 and 10 nanoseconds. The energy of the laser is continually variable between 0.1 and 3.0 millijoules. The detector is a 17-stage venetian-blind multiplier made by Thorn EMI. The analysis is carried out under vacuum, usually between 10(exp -8) and 10(exp -9) Torr. The LIMA 3 has several useful features such as: a He-Ne pilot laser used to target the Nd:YAG laser; a microscope (which is used to view the sample through the laser optics); and a precision sample stage for accurate sample alignment.

  3. Laser beam guard clamps

    Science.gov (United States)

    Dickson, Richard K.

    2010-09-07

    A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

  4. Laser induced plasma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Kim, Nak Bae; Woo, Hyung Joo; Kim, Joon Kon; Kim, Gi Dong; Choi, Han Woo; Yoon, Yoon Yeol; Shim, Sang Kwun [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    When the pulsed laser is focused onto a small spot of a solid surface, an optically induced plasma is formed at this surface. This plasma will be formed when the laser power density exceeds the breakdown threshold value of the solid surface. The interaction of high power laser light with a target or solid materials have been an active topic not only in plasma physics but also in the field of analytical chemistry. Recently, LIPS(laser induced plasma spectroscopy) has been applied many kinds of sample analysis including solid, liquid and gas analysis. LIPS has a advantage of the minimal sample preparation required for a solid sample and ability to analyze conducting as well as nonconducting materials, multi-elemental analysis. But this method has a poorer sensitivity than several competing atomic spectroscopic methods and semiquantitative analysis. Numerous factors affect the ablation process, including the laser pulse properties, such as pulse width, spatial and temporal fluctuations of the pulse and laser power fluctuations. The mechanical, physical and chemical properties of the sample also influence the ablation process. We studied LIPS with Nd:YAG second harmonic 532 nm and the induced plasma temperature was studied by observing the emission intensity of Fe(I) line and the plasma temperature of the different kind of samples were calculated using Boltzmann plotting method under same laser condition. Using the above experimental results, LIPS has been applied for the analysis of the elemental distribution mapping of the polished rock section. For the elemental mapping analysis, XY stage controlled by step motor and PC were used and 5 x 5 mm element image was obtained. For the quantitative analysis, rock standard samples were analyzed and Ba, Cu, Fe, Mn, Si and Sr calibration curve were obtained. (author). 22 refs., 2 tabs., 14 figs.

  5. Spins, charge radii and magnetic moments of neutron-rich Mn isotopes measured with bunched beam Collinear Laser Spectroscopy

    CERN Document Server

    AUTHOR|(CDS)2085887; Heylen, Hanne

    In this work, the odd-even $^{51–63}$Mn isotopes have been analyzed using collinear laser spectroscopy, from which the magnetic dipole moment and the change in change in mean square charge radius can be determined. The magnetic moment is very sensitive to the composition of the total nuclear wave function, while the charge radius gives information about the relative size and degree of deformation of the nucleus. An additional advantage of collinear laser spectroscopy is the possibility of direct measurement of the nuclear spin. The main motivation behind the study of these isotopes is to investigate the change in nuclear structure when approaching neutron number N = 40. This region is of interest due to the apparent doubly magic nature of $^{68}$Ni , which is not seen in the N = 40 isotopes of $^{26}$Fe and $^{24}$Cr. Mn, situated between these elements, offers another perspective due to its uncoupled proton. Based on the observed spectra and extracted moments, spins were assigned to $^{59,61,63}$Mn. The ex...

  6. Smartphone laser beam spatial profiler.

    Science.gov (United States)

    Hossain, Md Arafat; Canning, John; Cook, Kevin; Jamalipour, Abbas

    2015-11-15

    A simple, low-cost, portable, smartphone-based laser beam profiler for characterizing laser beam profiles is reported. The beam profiler utilizes a phosphor silica glass plate to convert UV light into visible (green) light that can be directly imaged onto an existing smartphone CMOS chip and analyzed using a customized app. 3D printing enables the ready fabrication of the instrument package. The beam's diameter, shape, divergence, beam quality factor, and output power are measured for two UV lasers: a CW 244 nm frequency-doubled Ar ion laser and a pulsed 193 nm ArF exciplex laser. The availability of specialized phosphor converters can extend the instrument from the UV to the near infrared and beyond, and the smartphone platform extends the Internet of Things to map laser beam profiles simultaneously in different locations. PMID:26565823

  7. Stark spectroscopy of a probe lithium beam excited with two dye lasers as a technique to study a high-power ion-beam diode

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, B. A. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); An, W.; Bluhm, H. [Karlsruhe Institute of Technology (KIT), Institute for Pulsed Power and Microwave Technology (IHM), D-76131 Karlsruhe (Germany)

    2012-03-15

    A non-disturbing measurement of electric field distributions is a subject of special interest in plasma physics and high-voltage devices. In this paper we describe a diagnostic technique for remote sensing of electric fields via injection of a probe beam of lithium atoms and cascade excitation of resonance fluorescence with two broadband dye lasers. The fluorescence spectrum was recorded using a monochromator equipped with an optical multi-channel analyser. The magnitude of the local electric field was retrieved from the Stark-shifted components of the 3d-2plithium spectral line. The technique was applied to measurements of the electric field in the applied-B-field high-voltage diode of the 1 TW KALIF ion-beam accelerator.

  8. Stark spectroscopy of a probe lithium beam excited with two dye lasers as a technique to study a high-power ion-beam diode.

    Science.gov (United States)

    Knyazev, B A; An, W; Bluhm, H

    2012-03-01

    A non-disturbing measurement of electric field distributions is a subject of special interest in plasma physics and high-voltage devices. In this paper we describe a diagnostic technique for remote sensing of electric fields via injection of a probe beam of lithium atoms and cascade excitation of resonance fluorescence with two broadband dye lasers. The fluorescence spectrum was recorded using a monochromator equipped with an optical multi-channel analyser. The magnitude of the local electric field was retrieved from the Stark-shifted components of the 3d-2p lithium spectral line. The technique was applied to measurements of the electric field in the applied-B-field high-voltage diode of the 1 TW KALIF ion-beam accelerator. PMID:22462900

  9. Nonlinear combining of laser beams.

    Science.gov (United States)

    Lushnikov, Pavel M; Vladimirova, Natalia

    2014-06-15

    We propose to combine multiple laser beams into a single diffraction-limited beam by beam self-focusing (collapse) in a Kerr medium. Beams with total power above critical are first combined in the near field and then propagated in the optical fiber/waveguide with Kerr nonlinearity. Random fluctuations during propagation eventually trigger a strong self-focusing event and produce a diffraction-limited beam carrying the critical power. PMID:24978503

  10. Nonlinear combining of laser beams

    OpenAIRE

    Lushnikov, Pavel M.; Vladimirova, Natalia

    2014-01-01

    We propose to combine multiple laser beams into a single diffraction-limited beam by the beam self-focusing (collapse) in the Kerr medium. The beams with the total power above critical are first combined in the near field and then propagated in the optical fiber/waveguide with the Kerr nonlinearity. Random fluctuations during propagation eventually trigger strong self-focusing event and produce diffraction-limited beam carrying the critical power.

  11. BECOLA Beam Line Construction and Laser System

    Science.gov (United States)

    Pedicini, Eowyn; Minamisono, Kei; Barquest, Brad; Bollen, Georg; Klose, Andrew; Mantica, Paul; Morrissey, Dave; Ringle, Ryan; Schwarz, Stefan; Vinnikova, Sophia

    2010-11-01

    The BECOLA (BEam COoler and LAser spectroscopy) facility is being installed at NSCL for experiments on radioactive nuclides.ootnotetextK. Minamisono et al, Proc. Inst. Nucl. Theory 16, 180 (2009). Low energy ion beams will be cooled/bunched in an RFQ ion trap and then extracted to a max of 60 kV. The ion beam will be neutralized through a charge exchange cell (CEC), and remaining ions will be removed by a deflector and collected in a Faraday cup. Collinear laser spectroscopy will be used to measure the atomic hyperfine structure, and nuclear properties will be extracted. The assembly, vacuum testing, and optical alignment of the CEC have been completed and the ion deflector and Faraday cup were also assembled. Stabilization of the Ti:sapphire laser to be used for spectroscopy is achieved through a feedback loop using a precision wavelength meter that is calibrated by a stabilized He-Ne laser. Coupling the He-Ne laser into a single-mode optical fiber was optimized for stable operation of the feedback loop. Finally, a wall chart of nuclear moments was prepared to view trends in μ and Q for nuclear ground states for planning future measurements.

  12. Study on laser atomic spectroscopy

    International Nuclear Information System (INIS)

    Electric discharge type atomic vaporizer is developed for the spectroscopic study on actinide elements. Laser induced fluorescence study on actinide elements is performed by using this high temperature type atomizer. For the effective photoionization of elements, copper vapor laser pumped dye laser and electron beam heating type atomic vaporizer are built and their characteristics are measured. In addition, resonance ionization mass spectroscopic analysis for lead sample as well as laser induced fluorescence study on uranium sample in solution phase is made. (Author)

  13. Raman spectroscopy characterization of actinide oxides (U 1-yPu y)O 2: Resistance to oxidation by the laser beam and examination of defects

    Science.gov (United States)

    Jégou, C.; Caraballo, R.; Peuget, S.; Roudil, D.; Desgranges, L.; Magnin, M.

    2010-10-01

    Structural changes in four (U 1-yPu y)O 2 materials with very different plutonium concentrations (0 ⩽ y ⩽ 1) and damage levels (up to 110 dpa) were studied by Raman spectroscopy. The novel experimental approach developed for this purpose consisted in using a laser beam as a heat source to assess the reactivity and structural changes of these materials according to the power supplied locally by the laser. The experiments were carried out in air and in water with or without hydrogen peroxide. As expected, the material response to oxidation in air depends on the plutonium content of the test oxide. At the highest power levels U 3O 8 generally forms with UO 2 whereas no significant change in the spectra indicating oxidation is observed for samples with high plutonium content ( 239PuO 2). Samples containing 25 wt.% plutonium exhibit intermediate behavior, typified mainly by a higher-intensity 632 cm -1 peak and the disappearance of the 1LO peak at 575 cm -1. This can be attributed to the presence of anion sublattice defects without any formation of higher oxides. The range of materials examined also allowed us to distinguish partly the chemical effects of alpha self-irradiation. The results obtained with water and hydrogen peroxide (a water radiolysis product) on a severely damaged 238PuO 2 specimen highlight a specific behavior, observed for the first time.

  14. Laser spectroscopy of U and UF6

    International Nuclear Information System (INIS)

    In the laser isotope speparation method, uranium atoms or molecules, usually UF6, are excited by a laser beam with a wavelength tunability and narrow linewidth, before they are fixed by an appropriate procedure. Therefore it is important to know the basic laser photo-excitation process. From this point of view, spectroscopic studies were performed for uranium atom (U) and molecule (UF6). Highly resolved fluorescence and absorption spectra of U were obtained mainly for the energy level of 16900 cm-1 by vaporizing uranium metal, producing an atomic beam and irradiating it with a narrow bandwidth laser beam. From these spectra, the isotope shift, the hyperfine structure and the photo-absorption cross section were obtained. And using a pulsed laser beam source, lifetimes of excited states of uranium atoms were measured. Vibrational and vibronic states of UF6 were also studied using a solid film of pure UF6 or a mixture of UF6 and buffer gas formed on a cold plate. Using a Raman spectroscopy, it was revealed that a peak of a vibrational spectrum is slightly influenced by the concentration of the buffer gas added in UF6. From the measurement of the absorption and the fluorescence spectrum for the X-A tilde transition, some progressions of the vibrational modes were observed. (author)

  15. Development of the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line

    International Nuclear Information System (INIS)

    The CRIS (Collinear Resonant Ionisation Spectroscopy) beam line is a new experimental set up at the ISOLDE facility at CERN. CRIS is being constructed for high-resolution laser spectroscopy measurements on radioactive isotopes. These measurements can be used to extract nuclear properties of isotopes far from stability. The CRIS beam line has been under construction since 2009 and testing of its constituent parts have been performed using stable and radioactive ion beams, in preparation for its first on-line run. This paper will present the current status of the CRIS experiment and highlight results from the recent tests.

  16. COMPLIS: COllinear spectroscopy Measurements using a Pulsed Laser Ion Source

    CERN Multimedia

    2002-01-01

    A Pulsed Laser spectroscopy experiment has been installed for the study of hyperfine structure and isotope shift of refractory and daughter elements from ISOLDE beams. It includes decelerated ion-implantation, element-selective laser ionization, magnetic and time-of-flight mass separation. The laser spectroscopy has been performed on the desorbed atoms in a set-up at ISOLDE-3 but later on high resolution laser collinear spectroscopy with the secondary pulsed ion beam is planned for the Booster ISOLDE set-up. During the first operation time of ISOLDE-3 we restricted our experiments to Doppler-limited resonant ionization laser and $\\gamma$-$\\gamma$ nuclear spectroscopy on neutron deficient platinum isotopes of even mass number down to A~=~186 and A~=~179 respectively. These isotopes have been produced by implantation of radioactive Hg and their subsequent $\\beta$-decay.

  17. Scintigram processing by laser beams

    International Nuclear Information System (INIS)

    Two methods of scintigram processing by laser beams are introduced and demonstrated by a number of examples. In one method, holographic or coherent-optical filters are used to suppress certain ranges of the spatial frequency spectrum in the spectral plane. The modulation transfer functions must be determined. In the other method, image smoothing by Gabor's method is performed by means of a laser beam instead of the cathode ray tube with a rotating electron beam. The signal-to-noise ratio is greatly improved in this way. (ORU)

  18. Laser processing with specially designed laser beam

    Science.gov (United States)

    Asratyan, A. A.; Bulychev, N. A.; Feofanov, I. N.; Kazaryan, M. A.; Krasovskii, V. I.; Lyabin, N. A.; Pogosyan, L. A.; Sachkov, V. I.; Zakharyan, R. A.

    2016-04-01

    The possibility of using laser systems to form beams with special spatial configurations has been studied. The laser systems applied had a self-conjugate cavity based on the elements of copper vapor lasers (LT-5Cu, LT-10Cu, LT-30Cu) with an average power of 5, 10, or 30 W. The active elements were pumped by current pulses of duration 80-100 ns. The duration of laser generation pulses was up to 25 ns. The generator unit included an unstable cavity, where one reflector was a special mirror with a reflecting coating. Various original optical schemes used were capable of exploring spatial configurations and energy characteristics of output laser beams in their interaction with micro- and nanoparticles fabricated from various materials. In these experiments, the beam dimensions of the obtained zones varied from 0.3 to 5 µm, which is comparable with the minimum permissible dimensions determined by the optical elements applied. This method is useful in transforming a large amount of information at the laser pulse repetition rate of 10-30 kHz. It was possible to realize the high-precision micromachining and microfabrication of microscale details by direct writing, cutting and drilling (with the cutting width and through-hole diameters ranging from 3 to 100 µm) and produce microscale, deep, intricate and narrow grooves on substrate surfaces of metals and nonmetal materials. This system is used for producing high-quality microscale details without moving the object under treatment. It can also be used for microcutting and microdrilling in a variety of metals such as molybdenum, copper and stainless steel, with a thickness of up to 300 µm, and in nonmetals such as silicon, sapphire and diamond with a thickness ranging from 10 µm to 1 mm with different thermal parameters and specially designed laser beam.

  19. Development of the collinear laser beam line at TRIUMF

    International Nuclear Information System (INIS)

    The low-energy collinear laser beam line at ISAC routinely produces highly nuclear-spin polarized beams of 8Li+ for depth-controlled studies of thin films and near-surface phenomena. It also is used for nuclear structure and fundamental symmetry studies requiring other beams of polarized lithium and sodium isotopes. Further development of polarized 20F and 11Be beams is described, the latter in some detail. Laser fluorescence spectroscopy at high sensitivity using unpolarized bunched beams is briefly mentioned.

  20. Gaussian-Beam Laser-Resonator Program

    Science.gov (United States)

    Cross, Patricia L.; Bair, Clayton H.; Barnes, Norman

    1989-01-01

    Gaussian Beam Laser Resonator Program models laser resonators by use of Gaussian-beam-propagation techniques. Used to determine radii of beams as functions of position in laser resonators. Algorithm used in program has three major components. First, ray-transfer matrix for laser resonator must be calculated. Next, initial parameters of beam calculated. Finally, propagation of beam through optical elements computed. Written in Microsoft FORTRAN (Version 4.01).

  1. Studies on laser atomic spectroscopy

    International Nuclear Information System (INIS)

    Laser atomic spectroscopy is studied both theoretically and experimentally. For Na-like ions, possible electric dipole, quadrupole and magnetic dipole transitions between atomic levels below 4f doublet F (J=7/2) state are investigated, using the recently developed computer programs - MCDF, MJE and MULTPOL. Line strength, oscillator strength and transition probability are calculated. A preliminary results for Hg-RIS experiment are also presented. Q-switched Nd:YAG laser, high power dye laser, vacuum system, ionization cell and ion measuring system are constructed, and their characteristics are examined. (Author)

  2. Nuclear Structure by Laser Spectroscopy

    International Nuclear Information System (INIS)

    This report illustrates the contribution of laser spectroscopy to our knowledge about variations of nuclear charge radii in long isotopic and isotonic chains comprising stable and short lived isotopes. The recent results obtained experimentally in the Flerov Laboratory of Nuclear Reactions, JINR, Dubna, are presented and discussed. (author). 32 refs.; 9 figs

  3. Production of radioactive ion beams and resonance ionization spectroscopy with the laser ion source at on-line isotope separator ISOLDE

    International Nuclear Information System (INIS)

    Full text: The resonance ionisation laser ion source (RILIS) of the ISOLDE on-line isotope separation facility at CERN is based on the method of laser step-wise resonance ionisation of atoms in a hot metal cavity. Using the system of dye lasers pumped by copper vapour lasers the ion beams of many different metallic elements have been produced at ISOLDE with an ionization efficiency of up to 27%. The high selectivity of the resonance ionization is an important asset for the study of short-lived nuclides produced in targets bombarded by the proton beam of the CERN Booster accelerator. Radioactive ion beams of Be, Mg, Al, Mn, Ni, Cu, Zn, Ga, Ag, Cd, In, Sn, Sb, Tb, Yb, Tl, Pb and Bi have been generated with the RILIS. Setting the RILIS laser in the narrow line-width mode provides conditions for a high-resolution study of hyperfine structure and isotopic shifts of atomic lines for short-lived isotopes. The isomer selective ionization of Cu, Ag and Pb isotopes has been achieved by appropriate tuning of laser wavelengths

  4. High energy density physics with intense ion and laser beams. Annual report 2003

    International Nuclear Information System (INIS)

    The following topics are dealt with: Laser plasma physics, plasma spectroscopy, beam interaction experiments, atomic and radiation physics, pulsed power applications, beam transport and accelerator research and development, properties of dense plasma, instabilities in beam-plasma interaction, beam transport in dense plasmas, short-pulse laser-matter interaction. (HSI)

  5. High energy density physics with intense ion and laser beams. Annual report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Weyrich, K. (comp.)

    2004-07-01

    The following topics are dealt with: Laser plasma physics, plasma spectroscopy, beam interaction experiments, atomic and radiation physics, pulsed power applications, beam transport and accelerator research and development, properties of dense plasma, instabilities in beam-plasma interaction, beam transport in dense plasmas, short-pulse laser-matter interaction. (HSI)

  6. Laser spectroscopy of sputtered atoms

    International Nuclear Information System (INIS)

    The use of laser radiation to study the sputtering process is of relatively recent origin. Much has been learned from this work about the basic physics of the sputtering process itself through measurements of velocity and excited state distributions of sputtered atoms and the effects of adsorbates on substrate sputtering yields. Furthermore, the identification, characterization, and sensitive detection of sputtered atoms by laser spectroscopy has led to the development of in situ diagnostics for impurity fluxes in the plasma edge regions of tokamaks and of ultrasensitive methods (ppB Fe in Si) for surface analysis with ultralow (picocoulomb) ion fluences. The techniques involved in this work, laser fluorescence and multiphoton resonance ionization spectroscopy, will be described and illustrations given of results achieved up to now. 55 refs., 5 figs., 1 tab

  7. Stable isotope laser spectroscopy

    Science.gov (United States)

    Becker, J. F.; Yaldaei, Ramil; Mckay, Christopher P.

    1989-01-01

    Recent advances in semiconductor laser technology have produced a reliable lightweight device ideally suited for a spacecraft high resolution molecular spectrometer. Lead-salt tunable diode lasers (TDL) emit in several spectral modes, each with a very narrow linewidth of -0.0003/cm. This spectral resolution is much narrower than typical Doppler broadened molecular linewidths in the mid-IR range. Thus it is possible to detect individual rotational lines within the vibrational band and measure their intensity, which can be used to determine gas concentration. The narrow spectral lines of any impurity gas tend to lie between the narrow lines of the gas of interest. This represents a major advantage over the accepted gas chromatograph mass spectrometer (GCMS) technique for measuring gas concentrations and isotope ratios. The careful and extensive gas purification procedures required to remove impurities for reliable GCMS measurements will not be required for an IR laser gas analysis. The infrared laser gas analysis technique is being developed to measure stable isotopic ratios of gases such as CO2, CH4, N2O, and NH3. This will eventually lead to development of instruments capable of in situ istopic measurements on planets such as Mars. The carbon (C-12, C-13) isotope ratio is indicative of the type of carbon fixation mechanisms (e.g., photosynthesis, respiration) in operation on a planet, while the nitrogen (N-14, N-15) isotope ratio can probably be used to date nitrogen-bearing Martian samples. The absorbance ratio of two adjacent lines of CO2 in the 2300/cm (4.3 micron) region of the spectrum was measured. The precision of the measurement is presently better than 1 percent and significant improvement is anticipated as rapid sweep-integration techniques and computer controlled data acquistion capabilities are incorporated.

  8. The effect of the laser wavelength on collinear double pulse laser induced breakdown spectroscopy (DP-LIBS)

    Science.gov (United States)

    Wang, Qi; Lin, Yanqing; Liu, Jing; Fan, Shuang; Xu, Zhuopin; Huang, Qing; Wu, Yuejin

    2016-05-01

    The pulsed lasers at wavelengths of 532 nm and 1064 nm were used as two beams of light for collinear double pulse laser induced breakdown spectroscopy (DP-LIBS). By changing the time sequence of two beams of different lasers, we studied the effect of the interval of two pulses of DP-LIBS on spectral signals compared with single pulsed (SP) LIBS.

  9. Beam alignment system for laser welding system

    International Nuclear Information System (INIS)

    The patent describes a beam alignment system for laser welding work pieces, such as fuel rod grids for nuclear fuel assemblies. The apparatus for performing various laser-machining comprises a beam alignment system including alignment target means, as well as means for emitting, directing and focusing the laser beam. (U.K.)

  10. Laser beam steering device

    Science.gov (United States)

    Motamedi, M. E.; Andrews, A. P.; Gunning, W. J.

    1993-01-01

    Agile beam steering is a critical requirement for airborne and space based LIDAR and optical communication systems. Design and test results are presented for a compact beam steering device with low inertia which functions by dithering two complementary (positive and negative) binary optic microlens arrays relative to each other in directions orthogonal to the direction of light propagation. The miniaturized system has been demonstrated at scan frequencies as high as 300 Hz, generating a 13 x 13 spot array with a total field of view of 2.4 degrees. The design is readily extendable to a 9.5 degree field of view and a 52 x 52 scan pattern. The system is compact - less than 2 in. on a side. Further size reductions are anticipated.

  11. Application of nondiffracting laser beam to laser compton scattering

    CERN Document Server

    Li, D; Aoki, M; Miyamoto, S; Amano, S; Mochizuki, T

    2003-01-01

    Nondiffracting laser beam - J sub 0 Bessel beam, is suggested to take the place of conventional Gaussian laser beam in a laser Compton scattering system, in order to increase the flux of scattered photons through maintaining an efficient interaction of electron beam and laser beam in a long distance. A novel cavity is proposed to produce and store the J sub 0 Bessel beam based on our present laser Compton scattering experimental setup for gamma-ray generation, and the propagation features and intensity distribution of the J sub 0 Bessel beam inside the cavity are analyzed. The flux of Compton scattering gamma-ray is estimated theoretically and the results reveal that a significant growth are accomplished with the use of J sub 0 Bessel laser beam contrasting with the use of Gaussian laser beam. (author)

  12. Laser spectroscopy of cold molecules

    CERN Document Server

    Borri, Simone

    2016-01-01

    This paper reviews the recent results in high-resolution spectroscopy on cold molecules. Laser spectroscopy of cold molecules addresses issues of symmetry violation, like in the search for the electric dipole moment of the electron and the studies on energy differences in enantiomers of chiral species; tries to improve the precision to which fundamental physical constants are known and tests for their possible variation in time and space; tests quantum electrodynamics, and searches for a fifth force. Further, we briefly review the recent technological progresses in the fields of cold molecules and mid-infrared lasers, which are the tools that mainly set the limits for the resolution that is currently attainable in the measurements.

  13. Laser Diode Beam Basics, Manipulations and Characterizations

    CERN Document Server

    Sun, Haiyin

    2012-01-01

    Many optical design technical books are available for many years which mainly deal with image optics design based on geometric optics and using sequential raytracing technique. Some books slightly touched laser beam manipulation optics design. On the other hand many books on laser diodes have been published that extensively deal with laser diode physics with little touching on laser diode beam manipulations and characterizations. There are some internet resources dealing with laser diode beams. However, these internet resources have not covered enough materials with enough details on laser diode beam manipulations and characterizations. A technical book concentrated on laser diode beam manipulations and characterizations can fit in to the open and provide useful information to laser diode users. Laser Diode Beam Basics, Manipulations and  Characterizations is concentrated on the very practical side of the subject, it only discusses the basic physics and mathematics that are necessary for the readers in order...

  14. Laser spectroscopy used in nuclear physics; La spectroscopie laser appliquee a la physique nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Le Blanc, F

    2001-04-05

    The study of nuclear shapes is a basic topic since it constitutes an excellent ground for testing and validating nuclear models. Measurements of the electron quadrupolar moment, of the nuclear charge radius and of the magnetic dipolar moment shed light on the nuclear deformation. Laser spectroscopy is a specific tool for such measurements, it is based on the interaction of the nucleus with the surrounding electron cloud (hyperfine structure), it is then an external approach of the shape of the nucleus whereas the classical nuclear spectroscopy ({alpha}, {beta} or {gamma}) gives information on the deformation from the inside of the nucleus. The author describes 2 techniques of laser spectroscopy: the colinear spectroscopy directly applied to a beam issued from an isotope separator and the resonant ionization spectroscopy linked with atom desorption that allows the study of particular nuclei. In order to illustrate both methods some effective measurements are presented: - the colinear spectroscopy has allowed the achievement of the complete description of the isomeric state (T = 31 years) of hafnium-178; - The experiment Complis has revealed an unexpected even-odd zigzag effect on very neutron-deficient platinum isotopes; and - the comparison of 2 isotopes of gold and platinum with their isomers has shown that the inversion of 2 levels of neutron, that was found out by nuclear spectroscopy, is in fact a consequence of a change in the nuclear shape. (A.C.)

  15. Free-electron laser beam

    International Nuclear Information System (INIS)

    The principle and history of free-electron laser (FEL), first evidenced in 1977, the relationship between FEL wavelength and output power, the high-power FEL driven by the superconducting linac, the X-ray FEL by the linac, and the medical use are described. FEL is the vacuum oscillator tube and essentially composed from the high-energy linac, undulator and light-resonator. It utilizes free electrons in the vacuum to generate the beam with wavelength ranging from microwave to gamma ray. The first high-power FEL developed in Japanese Atomic Energy Research Institute (JAERI) is based on the development of superconducting linac for oscillating the highest power beam. In the medical field, applications to excise brain tumors (in US) and to reconstruct experimentally blood vessels in the pig heart (in Gunma University) by lasing and laser coagulator are in progress with examinations to remove intra-vascular cholesterol mass by irradiation of 5.7μm FEL beam. Cancer cells are considered diagnosed by FEL beam of far-infrared-THz range. The FEL beam CT is expected to have a wide variety of application without the radiation exposure and its resolution is equal or superior to that of usual imaging techniques. (N.I.)

  16. Laser induced fluorescence spectroscopy for FTU

    International Nuclear Information System (INIS)

    Laser induced fluorescence spectroscopy (LIFS) is based on the absorption of a short pulse of tuned laser light by a group of atoms and the observation of the resulting fluorescence radiation from the excited state. Because the excitation is resonant it is very efficient, and the fluorescence can be many times brighter than the normal spontaneous emission, so low number densities of the selected atoms can be detected and measured. Good spatial resolution can be achieved by using a narrow laser beam. If the laser is sufficiently monochromatic, and it can be tuned over the absorption line profile of the selected atoms, information can also be obtained about the velocities of the atoms from the Doppler effect which can broaden and shift the line. In this report two topics are examined in detail. The first is the effect of high laser irradiance, which can cause 'power broadening' of the apparent absorption line profile. The second is the effect of the high magnetic field in FTU. Detailed calculations are given for LIFS of neutral iron and molybdenum atoms, including the Zeeman effect, and the implementation of LIFS for these atoms on FTU is discussed

  17. Binding Energies of the pi-Stacked Anisole Dimer: New Molecular Beam-Laser Spectroscopy Experiments and CCSD(T) Calculations

    Czech Academy of Sciences Publication Activity Database

    Řezáč, Jan; Nachtigallová, Dana; Mazzoni, F.; Pasquini, M.; Pietraperzia, G.; Becucci, M.; Müller-Dethlefs, K.; Hobza, Pavel

    2015-01-01

    Roč. 21, č. 18 (2015), s. 6740-6746. ISSN 0947-6539 R&D Projects: GA ČR GBP208/12/G016 Grant ostatní: GA MŠk(CZ) ED2.1.00/03.0058 Institutional support: RVO:61388963 Keywords : binding energy * noncovalent interactions * pi stacking * laser spectroscopy * CCSD(T) calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.731, year: 2014

  18. LASER BEAM PROPAGATION THROUGH FOG

    OpenAIRE

    Duchet, M; Flocon, B.; Sap, J

    1980-01-01

    The atmosphere is characterized by its molecular absorption coefficient and the fog by the initial radius of droplets which can be drifted by the wind. Absorption and scattering coefficients of droplets are calculated by the MIE's theory from their radius and complex index. In the laser beam, droplets are partially vaporized (we neglect thermal conductivity). Propagation equations are solved by numerical means giving steady state in a first slice of atmosphere and by incremental process in th...

  19. Multi beam laser target illumination

    International Nuclear Information System (INIS)

    In order to compress matter to high densities by the application of intense pulses of laser energy it is necessary for the implosion of the target to be both stable and spherical. This imposes certain constraints on the uniformity of illumination of the target, and, this in turn places requirements on the illuminating optics and the laser beam quality. This report discusses the uniformity of illumination of a spherical target as provided by a variety of optical systems and for different numbers of laser beams and beam profiles. The results are compared with similar conclusions obtained by other workers. An alternative presentation of the calculations is given which is believed to be a more realistic estimate of the uniformity. Comments are made on the approximations that have been assumed and the results likely to be obtained from the full treatment are discussed. The effects of this non-uniform illumination on the target implosion are considered using the linear theory of the Rayleigh-Taylor instability. Finally, comments are made on other factors of a more practical nature which also govern the final choice of illumination system and the scope of experiments made possible by such a system. (author)

  20. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Science.gov (United States)

    Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

    2015-04-01

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  1. Cascaded injection resonator for coherent beam combining of laser arrays

    Science.gov (United States)

    Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

    2008-10-21

    The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

  2. Laser diagnostics for picosecond e-beams

    International Nuclear Information System (INIS)

    We propose a novel approach to picosecond e-bunch/laser pulse synchronization and spatial alignment based upon refraction and reflection of a laser beam on a plasma column created by relativistic electrons traveling through a gas or solid optical material. The technique may be used in laser accelerators and for general subpicosecond e-beam diagnostics

  3. Study on laser atomic spectroscopy

    International Nuclear Information System (INIS)

    Laser atomic spectroscopic study on actinium element has been performed in many areas of spectroscopy. The study on characteristic of atomic vapor has been proceeded for copper atom and the spatial density distribution of copper vapor is measured. This experimental data has been compared with the theoretically calculated data. In spectroscopic experiment, the first and second excited states for actinium element are identified and the most efficient ionization scheme for actinium element is identified. In addition, the corrosion problem for filament material due to the heating of the actinium element has been studied. (Author)

  4. Dual-wavelength quantum cascade laser for trace gas spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jágerská, J.; Tuzson, B.; Mangold, M.; Emmenegger, L. [Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Jouy, P.; Hugi, A.; Beck, M.; Faist, J. [Institute for Quantum Electronics, ETH Zürich, Wolfgang-Pauli-Str. 16, 8093 Zürich (Switzerland); Looser, H. [Institute for Aerosol and Sensor Technology, FHNW, Klosterzelgstrasse 2, 5210 Windisch (Switzerland)

    2014-10-20

    We demonstrate a sequentially operating dual-wavelength quantum cascade laser with electrically separated laser sections, emitting single-mode at 5.25 and 6.25 μm. Based on a single waveguide ridge, this laser represents a considerable asset to optical sensing and trace gas spectroscopy, as it allows probing multiple gas species with spectrally distant absorption features using conventional optical setups without any beam combining optics. The laser capability was demonstrated in simultaneous NO and NO{sub 2} detection, reaching sub-ppb detection limits and selectivity comparable to conventional high-end spectroscopic systems.

  5. Dual-wavelength quantum cascade laser for trace gas spectroscopy

    International Nuclear Information System (INIS)

    We demonstrate a sequentially operating dual-wavelength quantum cascade laser with electrically separated laser sections, emitting single-mode at 5.25 and 6.25 μm. Based on a single waveguide ridge, this laser represents a considerable asset to optical sensing and trace gas spectroscopy, as it allows probing multiple gas species with spectrally distant absorption features using conventional optical setups without any beam combining optics. The laser capability was demonstrated in simultaneous NO and NO2 detection, reaching sub-ppb detection limits and selectivity comparable to conventional high-end spectroscopic systems.

  6. M2 qualify laser beam propagation

    International Nuclear Information System (INIS)

    One of the most important properties of a laser resonator is the highly collimated or spatially coherent nature of the laser output beam. Laser beam diameter and quality factor M2 are significant parameters in a wide range of laser applications. This is because the spatial beam quality determines how closely the beam can be focused or how well the beam propagates over long distances without significant dispersion. In the present paper we have used three different methods to qualify the spatial structure of a laser beam propagating in free space, the results are obtained and discussed, and we have found that the Wigner distribution function is a powerful tool which allows a global characterization of any kind of beam

  7. Electron-beam initiated HF lasers

    International Nuclear Information System (INIS)

    Electron beams were used to ignite hydrogen/fluorine mixtures, producing laser energies up to 4.2 kJ, and giving hope that this approach may soon produce energy levels suitable for laser-fusion studies. (auth)

  8. Method for splitting low power laser beams

    Energy Technology Data Exchange (ETDEWEB)

    Pierscionek, B.K. (University of Melbourne, Optometry Department, Parkville, Victoria 3052, Australia (AU))

    1990-04-01

    A new method for producing parallel rays from a laser beam using a cylindrical lens and pinholes is presented. This method can produce a greater number of emergent rays than using a {ital beam} {ital splitter}.

  9. Beam-Steering Subsystem For Laser Communication

    Science.gov (United States)

    Lesh, James R.; Chen, Chien-Chung; Ansari, Homayoon

    1995-01-01

    Proposed free-space laser communication system contains fewer optical and mechanical components. Involves novel fast beam-steering subsystem stabilizing only angle between transmitting and receiving beams instead of stabilizing both transmitting and receiving lines of sight individually. Received and transmitted beams of light both imaged onto CCD array at focal plane. Relative angular positions of beams computed from centroids of their images.

  10. Resonant Laser Cooling of Circular Accelerator Beams

    OpenAIRE

    Tumanian, R. V.

    2004-01-01

    The resonant laser cooling of circular accelerator beams of relativistic charged particle is studied. It is shown that in the approximation of the given external electromagnetic wave amplitude (small gain free electron laser) the emittance of a beam of charged particles decreases. In the field of particle energy about 100 in the mass energy units the beam energy losses are negligible. The discovered effect can be used for cooling of charged particle beams in various accelerators. The signific...

  11. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    International Nuclear Information System (INIS)

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region

  12. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, F., E-mail: federica.bonomo@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Gas Ionizzati - CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Barbisan, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cristofaro, S. [Universitá degli Studi di Padova, Via 8 Febbraio 2, 35122 Padova (Italy)

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  13. Angle-resolved X-ray photoelectron spectroscopy of topmost surface for LaNiO 3 thin film grown on SrTiO 3 substrate by laser molecular beam epitaxy

    Science.gov (United States)

    Chen, P.; Xu, S. Y.; Lin, J.; Ong, C. K.; Cui, D. F.

    1999-01-01

    The LaNiO 3 thin film was grown on SrTiO 3 (001) substrate by computer-controlled laser molecular beam epitaxy (laser MBE). In situ monitoring of the growing film surface was performed with a reflection high energy electron diffraction (RHEED). Angle-resolved X-ray photoelectron spectroscopy (ARXPS) indicated that the terminating plane of the LaNiO 3 film was the LaO atomic plane, and the SrTiO 3 (001) surfaces of as-supplied substrate as well as HF-pretreated substrate were predominantly terminated with TiO atomic plane. The structural conversion of the topmost atomic layer from NiO to LaO occurred during the LaNiO 3 epitaxial growth process.

  14. Laser frequency stabilization and shifting by using modulation transfer spectroscopy

    Science.gov (United States)

    Cheng, Bing; Wang, Zhao-Ying; Wu, Bin; Xu, Ao-Peng; Wang, Qi-Yu; Xu, Yun-Fei; Lin, Qiang

    2014-10-01

    The stabilizing and shifting of laser frequency are very important for the interaction between the laser and atoms. The modulation transfer spectroscopy for the 87Rb atom with D2 line transition F = 2 → F' = 3 is used for stabilizing and shifting the frequency of the external cavity grating feedback diode laser. The resonant phase modulator with electro—optical effect is used to generate frequency sideband to lock the laser frequency. In the locking scheme, circularly polarized pump- and probe-beams are used. By optimizing the temperature of the vapor, the pump- and probe-beam intensity, the laser linewidth of 280 kHz is obtained. Furthermore, the magnetic field generated by a solenoid is added into the system. Therefore the system can achieve the frequency locking at any point in a range of hundreds of megahertz frequency shifting with very low power loss.

  15. Laser frequency stabilization and shifting by using modulation transfer spectroscopy

    International Nuclear Information System (INIS)

    The stabilizing and shifting of laser frequency are very important for the interaction between the laser and atoms. The modulation transfer spectroscopy for the 87Rb atom with D2 line transition F = 2 → F' = 3 is used for stabilizing and shifting the frequency of the external cavity grating feedback diode laser. The resonant phase modulator with electro—optical effect is used to generate frequency sideband to lock the laser frequency. In the locking scheme, circularly polarized pump- and probe-beams are used. By optimizing the temperature of the vapor, the pump- and probe-beam intensity, the laser linewidth of 280 kHz is obtained. Furthermore, the magnetic field generated by a solenoid is added into the system. Therefore the system can achieve the frequency locking at any point in a range of hundreds of megahertz frequency shifting with very low power loss. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  16. Thermal Lensing Spectroscopy With Picosecond Pulse Trains and a New Dual Beam Configuration

    OpenAIRE

    Perry, J W; Ryabov, E. A.; Zewail, A.H.

    1982-01-01

    In this communication, we wish to report on the use of synchronously mode-locked picosecond lasers in a pump-probe configuration for TL spectroscopy. The peak power for these picosecond lasers is very high and, of course, the fundamental of the dye laser (red beam) can be efficiently (~10%) doubled in frequency (U.V. beam) by second harmonic generation in nonlinear crystals. We use this generated U.V. beam as a probe to monitor the very weak absorption of the red beam. An arrangement [4] of t...

  17. Laser Spectroscopy of neutron deficient Sn isotopes

    CERN Multimedia

    We propose to study the ground state properties of neutron-deficient tin isotopes towards the doubly-magic nucleus $^{100}$Sn. Nuclear spins, changes in the rms charge radii and electromagnetic moments of $^{101-121}$Sn will be measured by laser spectroscopy using the CRIS experimental beam line. These ground-state properties will help to clarify the evolution of nuclear structure properties approaching the $\\textit{N = Z =}$ 50 shell closures. The tin isotopic chain is currently the frontier for the application of state-of-the-art ab-initio calculations. Our knowledge of the nuclear structure of the Sn isotopes will set a benchmark for the advances of many-body methods, and will provide an important test for modern descriptions of the nuclear force.

  18. Laser Spectroscopy of Antiprotonic Helium Atoms

    CERN Multimedia

    2002-01-01

    %PS205 %title\\\\ \\\\Following the discovery of metastable antiprotonic helium atoms ($\\overline{p}He^{+} $) at KEK in 1991, systematic studies of their properties were made at LEAR from 1991 to 1996. In the first two years the lifetime of $\\overline{p}He^{+}$ in liquid and gaseous helium at various temperatures and pressures was measured and the effect of foreign gases on the lifetime of these atoms was investigated. Effects were also discovered which gave the antiproton a 14\\% longer lifetime in $^4$He than in $^3$He, and resulted in important differences in the shape of the annihilation time spectra in the two isotopes.\\\\ \\\\Since 1993 laser spectroscopy of the metastable $\\overline{p}He^{+}$ atoms became the main focus of PS205. Transitions were stimulated between metastable and non-metastable states of the $\\overline{p}He^{+}$ atom by firing a pulsed dye laser beam into the helium target every time an identified metastable atom was present (Figure 1). If the laser frequency matched the transition energy, the...

  19. Nuclear moments, spins and charge radii of copper isotopes from N=28 to N=50 by collinear fast-beam laser spectroscopy

    CERN Multimedia

    2002-01-01

    We aim at establishing an unambiguous spin determination of the ground and isomeric states in the neutron rich Cu-isotopes from A=72 up to A=78 and to measure the magnetic and quadrupole moments between the N=28 and N=50 shell closures. This study will provide information on the double-magicity of $^{56}$Ni and $^{78}$Ni, both at the extremes of nuclear stability. It will provide evidence on the suggested inversion of ground state spin around A$\\approx$74, due to the monopole migration of the $\\pi f_{5/2}$ level. The collinear laser spectroscopy technique will be used, which furthermore provides information on the changes in mean square charge radii between both neutron shell closures, probing a possible onset of deformation in this region.

  20. Robotics For High Power Laser Beam Manipulation

    Science.gov (United States)

    Watson, Henry E.

    1989-03-01

    The research and development programs in manufacturing science at The Pennsylvania State University have a major emphasis on laser materials processing technology development. A major thrust of this program is the development of an intelligent robotic system which can manipulate a laser beam in three dimension with the precision required for welding. The robot is called LARS for Laser Articulated Robotic System. A gantry based robot was selected as the foundation for LARS and the system is divided into five major subsystems: robot, electronic control, vision, workhead, beam transport, and software. An overview of the Laser Robotics program including laser materials processing research programs will be provided.

  1. POWER LASER BEAMING AND APPLICATIONS IN SPACE

    OpenAIRE

    Lee, JA; Conway, E.

    1991-01-01

    A brief overview of the concept of power laser beaming in space and its applications are presented. A direct solar-pumped iodine laser with the iodide t-C4F9I lasant is described as an example of the power laser system.

  2. Electron-beam-excited gas laser research

    International Nuclear Information System (INIS)

    Net energy gain in laser fusion places requirements on the laser that are not realized by any existing laser. Utilization of relativistic electron beams (REB's), a relatively new source for the excitation of gas laser media, may lead to new lasers that could satisfy these requirements. Already REB's have been utilized to excite gas laser media and produce gas lasers that have not been produced as successfully any other way. Electron-beam-excitation has produced electronic-transition dimer lasers that have not yet been produced by any other excitation scheme (for example, Xe2/ sup *(1)/, Kr:O(21S)/sup 2/, KrF/sup *(3)/). In addition, REB's have initiated chemical reactions to produce HF laser radiation with unique and promising results. Relativistic-electron-beam gas-laser research is continuing to lead to new lasers with unique properties. Results of work carried out at Sandia Laboratories in this pioneering effort of electron-beam-excited-gas lasers are reviewed. (U.S.)

  3. Generation of a hollow laser beam by a multimode fiber

    Institute of Scientific and Technical Information of China (English)

    Hongyu Ma; Huadong Cheng; Wenzhuo Zhang; Liang Liu; Yuzhu Wang

    2007-01-01

    A simple method to generate a hollow laser beam by multimode fiber is reported. A dark hollow laser beam is generated from a multimode fiber and the dependence of the output beam profile on the incident angle of laser beam is analyzed. The results show that this hollow laser beam can be used to trap and guide cold atoms.

  4. Decay-Assisted Laser Spectroscopy of Neutron-Deficient Francium

    CERN Document Server

    Lynch, K M; Bissell, M L; Budincevic, I; Cocolios, T E; De Groote, R P; De Schepper, S; Fedosseev, V N; Flanagan, K T; Franchoo, S; Garcia Ruiz, R F; Heylen, H; Marsh, B A; Neyens, G; Procter, T J; Rossel, R E; Rothe, S; Strashnov, I; Stroke, H H; Wendt, K D A

    2014-01-01

    This paper reports on the hyperfine-structure and radioactive-decay studies of the neutron-deficient francium isotopes $^{202-206}$Fr performed with the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at the ISOLDE facility, CERN. The high resolution innate to collinear laser spectroscopy is combined with the high efficiency of ion detection to provide a highly-sensitive technique to probe the hyperfine structure of exotic isotopes. The technique of decay-assisted laser spectroscopy is presented, whereby the isomeric ion beam is deflected to a decay spectroscopy station for alpha-decay tagging of the hyperfine components. Here, we present the first hyperfine-structure measurements of the neutron-deficient francium isotopes $^{202-206}$Fr, in addition to the identification of the low-lying states of $^{202,204}$Fr performed at the CRIS experiment.

  5. Laser diagnostic for high current H- beams

    International Nuclear Information System (INIS)

    In the last 5 years, significant technology advances have been made in the performance, size, and cost of solid-state diode-pumped lasers. These developments enable the use of compact Q-switched Nd:YAG lasers as a beam diagnostic for high current H- beams. Because the threshold for photodetachment is only 0.75 eV, and the maximum detachment cross section is 4x10-17cm2 at 1.5 eV, A 50 mJ/pulse Q-switched Nd:YAG laser can neutralize a significant fraction of the beam in a single 10 ns wide pulse. The neutral beam maintains nearly identical parameters as the parent H- beam, including size, divergence, energy, energy spread, and phase spread. A dipole magnet can separate the neutral beam from the H- beam to allow diagnostics on the neutral beam without intercepting the high-current H- beam. Such a laser system can also be used to extract a low current proton beam, or to induce fluorescence in partially stripped heavy ion beams. Possible beamline diagnostic systems will be reviewed, and the neutral beam yields will be calculated. copyright 1998 American Institute of Physics

  6. EXAFS-spectroscopy on synchrotron radiation beam

    CERN Document Server

    Aksenov, V L; Kuzmin, A Y; Purans, Y

    2001-01-01

    In the review the basis theoretical principles of EXAFS spectroscopy are given, as one of principal directions of an absorption spectroscopy permitting with a high accuracy to gain parameters of the short-range order in multicomponent amorphous and quasi-crystal mediums. The methods of the analysis of EXAFS spectra with allowance of effects of multiply scattering are featured. The exposition of the experimental set-ups, which realize the method of EXAFS spectroscopy on beams of SR, requirement of the monochromatization of radiation beams are given. For investigation of phase transition and external effects the energy-dispersive EXAFS spectrometer is creating at the National center of SR Kurchatov Institute which can measure the EXAFS spectrum with a time resolution 3-5 ms. The experimental results on investigation (by the EXAFS spectroscopy method) of oxides of tungsten and molybdenum are given, which have unique property: the variable valence of an ion of metal is depending on external action. The most inter...

  7. Adaptive optics for laser power beaming

    Science.gov (United States)

    Leland, Robert P.

    1992-01-01

    It has been proposed to use a high energy pulsed laser to beam power into space for satellites or a lunar base. The effects of atmospheric transmission are critical to such a system. Thermal blooming in the atmosphere can cause the beam to spread rapidly. Atmospheric turbulence can cause beam bending or beam spreading, resulting in the loss of transmitted energy that fails to hit the target receiver.

  8. Time-resolved and doppler-reduced laser spectroscopy on atoms

    International Nuclear Information System (INIS)

    Radiative lifetimes have been studied in neutral boron, carbon, silicon and strontium, in singly ionized gadolinium and tantalum and in molecular carbon monoxide and C2. The time-resolved techniques were based either on pulsed lasers or pulse-modulated CW lasers. Several techniques have been utilized for the production of free atoms and ions such as evaporation into an atomic beam, sputtering in hollow cathodes and laser-produced plasmas. Hyperfine interactions in boron, copper and strontium have been examined using quantum beat spectroscopy, saturation spectroscopy and collimated atomic beam spectroscopy. Measurement techniques based on effusive hollow cathodes as well as laser produced plasmas in atomic physics have been developed. Investigations on laser produced plasmas using two colour beam deflection tomography for determination of electron densities have been performed. Finally, new possibilities for view-time-expansion in light-in-flight holography using mode-locked CW lasers have been demonstrated. (au)

  9. Space Optical Communications Using Laser Beam Amplification

    Science.gov (United States)

    Agrawal, Govind

    2015-01-01

    The Space Optical Communications Using Laser Beam Amplification (SOCLBA) project will provide a capability to amplify a laser beam that is received in a modulating retro-reflector (MRR) located in a satellite in low Earth orbit. It will also improve the pointing procedure between Earth and spacecraft terminals. The technology uses laser arrays to strengthen the reflected laser beam from the spacecraft. The results of first year's work (2014) show amplification factors of 60 times the power of the signal beam. MMRs are mirrors that reflect light beams back to the source. In space optical communications, a high-powered laser interrogator beam is directed from the ground to a satellite. Within the satellite, the beam is redirected back to ground using the MMR. In the MMR, the beam passes through modulators, which encode a data signal onto the returning beam. MMRs can be used in small spacecraft for optical communications. The SOCLBA project is significant to NASA and small spacecraft due to its application to CubeSats for optical data transmission to ground stations, as well as possible application to spacecraft for optical data transmission.

  10. Micro-beam XRF localization by a laser beam

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A new method for micro-beam XRF localization is presented. A laserbeam along with an incident X-ray hits on the surface of a sample. The micro region onthe sample that reached by X-ray beam can be localized by means of thevisible spot of the laser beam. This method is suitable for X-ray microprobesusing anX-ray tube or synchrotron radiation as excitation sources.

  11. Acceleration of charged particles in laser beam

    Directory of Open Access Journals (Sweden)

    M.J. Małachowski

    2009-12-01

    Full Text Available Purpose: The aim of this paper was to find parameters of the laser and maser beams in numerical ways with additionally applied external static axial magnetic field which satisfies the proper conditions for charged particle acceleration.Design/methodology/approach: The set acceleration was designed in order to obtain the possible high kinetic energy of the charged particles in the controllable manner. This was achieved applying a circularly polarized high intensity laser beam and a static axial magnetic field, both acting on the particle during the proper period.Findings: The quantitative illustrations of the calculation results, in a graphical form enabled to discuss the impact of many parameters on the acceleration process of the electrons and protons. We have found the impact of the Doppler Effect on the acceleration process to be significant. Increase in laser or maser beam intensity results in particle’s energy increase and its trajectory dimension. However, increase in external magnetic field results in shrinking of the helical trajectories. It enables to keep the particle inside the laser beam.Research limitations/implications: Limits in the energy of accelerated particles arise from the limitsin up-to-date available laser beam energy and the beam diameters.Originality/value: The authors show the parameters of the circularly polarized laser beam which should be satisfied in order to obtain the desired energy of the accelerated particles. The influence of the magnetic field strength is also shown.

  12. Nuclear properties studied by laser spectroscopy

    International Nuclear Information System (INIS)

    Magnetic dipole and electric quadrupole moments of atomic nuclei are determined by means of laser spectroscopy model-independently. Laser-rf techniques enable us to make precision measurement of these moments. The hfs anomaly, i.e., Bohr-Weisskopf effect will be studied systematically at CERN ISOLDE shortly. (author)

  13. Simulation based analysis of laser beam brazing

    Science.gov (United States)

    Dobler, Michael; Wiethop, Philipp; Schmid, Daniel; Schmidt, Michael

    2016-03-01

    Laser beam brazing is a well-established joining technology in car body manufacturing with main applications in the joining of divided tailgates and the joining of roof and side panels. A key advantage of laser brazed joints is the seam's visual quality which satisfies highest requirements. However, the laser beam brazing process is very complex and process dynamics are only partially understood. In order to gain deeper knowledge of the laser beam brazing process, to determine optimal process parameters and to test process variants, a transient three-dimensional simulation model of laser beam brazing is developed. This model takes into account energy input, heat transfer as well as fluid and wetting dynamics that lead to the formation of the brazing seam. A validation of the simulation model is performed by metallographic analysis and thermocouple measurements for different parameter sets of the brazing process. These results show that the multi-physical simulation model not only can be used to gain insight into the laser brazing process but also offers the possibility of process optimization in industrial applications. The model's capabilities in determining optimal process parameters are exemplarily shown for the laser power. Small deviations in the energy input can affect the brazing results significantly. Therefore, the simulation model is used to analyze the effect of the lateral laser beam position on the energy input and the resulting brazing seam.

  14. High power laser beam delivery monitoring for laser safety

    Science.gov (United States)

    Corder, D. A.; Evans, D. R.; Tyrer, J. R.; Freeland, C. M.; Myler, J. K.

    1997-07-01

    The output of high power lasers used for material processing presents extreme radiation hazards. In normal operation this hazard is removed by the use of local shielding to prevent accidental exposure and system design to ensure efficient coupling of radiation into the workpiece. Faults in laser beam delivery or utilization can give rise to hazardous levels of laser radiation. A passive hazard control strategy requires that the laser system be enclosed such that the full laser power cannot burn through the housing under fault conditions. Usually this approach is too restrictive. Instead, active control strategies can be used in which a fault condition is detected and the laser cut off. This reduces the requirements for protective housing. In this work a distinction is drawn between reactive and proactive strategies. Reactive strategies rely on detecting the effects of an errant laser beam, whereas proactive strategies can anticipate as well as detect fault conditions. This can avoid the need for a hazardous situation to exist. A proactive strategy in which the laser beam is sampled at the final turning mirror is described in this work. Two control systems have been demonstrated; the first checks that beam power is within preset limits, the second monitors incoming beam power and position, and the radiation reflected back from the cutting head. In addition to their safety functions the accurate monitoring of power provides an additional benefit to the laser user.

  15. Electronic beam steering of semiconductor injection lasers

    Science.gov (United States)

    Katz, J.

    1982-01-01

    A theoretical analysis of the problem of beam steering is presented. The required modifications of the dielectric constant profile of the laser structure were derived. A practical method for implementing the needed modifications is outlined.

  16. Synchronous Characterization of Semiconductor Microcavity Laser Beam

    OpenAIRE

    WANG, Tao; Lippi, Gian-Luca

    2015-01-01

    We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam's tails deviations from the Gaussian shape, however, are accompanied by si...

  17. Theoretical tools for atom laser beam propagation

    OpenAIRE

    Riou, J. -F.; Coq, Y. Le; Impens, F; Guerin, W.; Bordé, C. J.; Aspect, A; Bouyer, P.

    2008-01-01

    We present a theoretical model for the propagation of non self-interacting atom laser beams. We start from a general propagation integral equation, and we use the same approximations as in photon optics to derive tools to calculate the atom laser beam propagation. We discuss the approximations that allow to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce...

  18. Laser beam riding artillery missiles guidance device is designed

    Science.gov (United States)

    Yan, Mingliang; Huo, Zhicheng; Chen, Wei

    2014-09-01

    Laser driving gun missile guidance type beam of laser information field formed by any link failure or reduced stability will directly lead to ballistic or miss out of control, and based on this, this paper designed the driving beam of laser guided missile guidance beam type forming device modulation and zoom mechanism, in order to make the missile can recognize its position in the laser beam, laser beam gun missile, by means of spatial encoding of the laser beam laser beam into information after forming device, a surface to achieve the purpose of precision guidance.

  19. Beam crossing studies in a Megajoule laser

    International Nuclear Information System (INIS)

    In the framework of laser-plasma interaction, this PhD thesis presents the studies on the effects produced by the intersection of two laser beams. This study is motivated by the CEA Megajoule laser project in which 240 beams cross at input holes of the enclosure containing the fusible target. Especially, the beating of two coherent laser beams create an interference figure, which, by the ponderomotive force, produces an ion acoustic wave. This specific acoustic wave is a Bragg grating in which each beam is diffracted in the exact direction of the other. It is an energy transfer mechanism between the two beams. This mechanism is modeled in two dimensions and is resolved analytically and numerically. The application of this easy model is qualitatively satisfying. In order to be nearer to the experimental conditions, the optical smoothing by slides of random phases has to be taken into account. This leads us to a statistical approach of exchanges and tends to confirm the hypothesis in which they are governed by hot spots. Simultaneously, stimulated Brillouin scattering and the intersection of two beams of the same frequencies have been treated. In our simulations appear a competition between Bragg diffraction and Brillouin scattering, this last one being modified compared to Brillouin scattering for an only one beam. We conclude in indicating some extrapolations for the Megajoule laser. (O.M.)

  20. Method for laser spectroscopy of metastable pionic helium atoms

    International Nuclear Information System (INIS)

    The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π− beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a helium nucleus, a π− occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic helium atoms at CERN

  1. Investigations in CO2 laser beam caustics measuring techniques

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Bagger, Claus

    2004-01-01

    The performance of an industrial laser is very much depending upon the characteristics of the laser beam. The ISO standards 11146 and 11154 which are describing test methods for laser beam parameters have been approved....

  2. Power Transmission by Using Laser Beams

    OpenAIRE

    Yamabe, Chobei; NAKAMURA, Keiji; Homma, Hiroshi; YAMAUCHI, Masao; OKAMOTO, Tatsuo; Ishihara, Hiroyuki; NAKAMURA, Toshihiko; TAKAGI, Shigeyuki; HORII, Kenji

    1988-01-01

    A method of power transmission using a laser beam for a very long distance has been proposed. A compact and high power TEA CO_2 laser has been developed and it has been applied to the plasma production for the power transmission. The characteristics of the direct energy conversion from laser energy to electricity with laser-produced plasma are reported here. It is found that the total conversion efficiency increases with laser output using a carbon target. The effect of surface magnetic confi...

  3. Vertical laser beam propagation through the troposphere

    Science.gov (United States)

    Minott, P. O.; Bufton, J. L.; Schaefer, W. H.; Grolemund, D. A.

    1974-01-01

    The characteristics of the earth's atmosphere and its effects upon laser beams was investigated in a series of balloon borne, optical propagation experiments. These experiments were designed to simulate the space to ground laser link. An experiment to determine the amplitude fluctuation, commonly called scintillation, caused by the atmosphere was described.

  4. Spectroscopy and Stark-effect of Rydberg states in Ca and Sr in an atomic beam experiment

    International Nuclear Information System (INIS)

    Rydberg states of Calcium and Strontium were excited by laser radiation in an atomic beam experiment. Such spectroscopy of the Rydberg series could be done in both elements and also the Stark effect was examined in Strontium. (BEF)

  5. Laser cooling of a stored ion beam: A first step towards crystalline beams

    Energy Technology Data Exchange (ETDEWEB)

    Hangst, J.S.

    1992-09-01

    This report discusses: a brief introduction to storage rings; crystalline beams; laser cooling of ion beams; description of astrid-the experimental setup; first experiments with lithium 7 ion beam; experiments with erbium 166 ion beams; further experiments with lithium 7 ion beams; beam dynamics, laser cooling,and crystalline beams in astrid; possibilities for further study in astrid.

  6. Laser cooling of a stored ion beam: A first step towards crystalline beams

    International Nuclear Information System (INIS)

    This report discusses: a brief introduction to storage rings; crystalline beams; laser cooling of ion beams; description of astrid-the experimental setup; first experiments with lithium 7 ion beam; experiments with erbium 166 ion beams; further experiments with lithium 7 ion beams; beam dynamics, laser cooling,and crystalline beams in astrid; possibilities for further study in astrid

  7. Controlling Second Harmonic Efficiency of Laser Beam Interactions

    Science.gov (United States)

    Barnes, Norman P. (Inventor); Walsh, Brian M. (Inventor); Reichle, Donald J. (Inventor)

    2011-01-01

    A method is provided for controlling second harmonic efficiency of laser beam interactions. A laser system generates two laser beams (e.g., a laser beam with two polarizations) for incidence on a nonlinear crystal having a preferred direction of propagation. Prior to incidence on the crystal, the beams are optically processed based on the crystal's beam separation characteristics to thereby control a position in the crystal along the preferred direction of propagation at which the beams interact.

  8. Accelerated ion beams for in-beam e-gamma spectroscopy

    NARCIS (Netherlands)

    Dionisio, JS; Vieu, C; Schuck, C; Meunier, R; Ledu, D; Lafoux, A; Lagrange, JM; Pautrat, M; Waast, B; Phillips, WR; Varley, BJ; Durell, JL; Dagnall, PG; Dorning, SJ; Jones, MA; Smith, AG; Bacelar, JCS; Rzaca-Urban, T; Folger, H; Vanhorenbeeck, J; Urban, W

    1998-01-01

    A few accelerated ion beam requirements for in-beam e-gamma spectroscopy are briefly reviewed as well as several features of the MP Tandem accelerator of IPN-Orsay and the accelerated ion-beam transport devices leading to the experimental area of in-beam e-gamma spectroscopy. In particular, the main

  9. Collinear laser-beam--ion-beam measurement of the mean lifetime of the Ar II 4p' 2F degree 7/2 level

    International Nuclear Information System (INIS)

    The mean lifetime τ of the 4p' 2F degree 7/2 level of Ar II has been measured using a variant of the collinear laser-beam--fast-ion-beam spectroscopy technique. Our variant requires no mechanical motion or laser frequency tuning. The result is τ=8.414±0.025 ns in agreement with an earlier, comparably precise, measurement based on a crossed laser--ion-beam technique. The result lies above all theoretical calculations

  10. Laser-accelerated proton beams as a new particle source

    Energy Technology Data Exchange (ETDEWEB)

    Nuernberg, Frank

    2010-11-15

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. In this work, an experimental method to fully reconstruct laser-accelerated proton beam parameters, called radiochromic film imaging spectroscopy (RIS), was developed. Since the proton beam expansion is a plasma expansion with accompanying electrons, a low-energy electron spectrometer was developed, built and tested to study the electron distribution matching to the proton beam energy distribution. Two experiments were carried out at the VULCAN Petawatt laser with the aim of showing dynamic control and enhancement of proton acceleration using multiple or defocused laser pulses. Irradiating the target with a long pulse, low-intensity laser (10{sup 12} W/cm{sup 2}) prior to the main pulse ({proportional_to}ns), an optimum pre-plasma density scale length of 60 {mu}m is generated leading to an enhancement of the maximum proton energy ({proportional_to}25%), the proton flux (factor of 3) and the beam uniformity. Proton beams were generated more efficiently than previously by driving thinner target foils at a lower intensity over a large area. The optimum condition was a 2 {mu}m foil irradiated with an intensity of 10{sup 19} W/cm{sup 2} onto a 60 {mu}m spot. Laser to proton beam efficiencies of 7.8% have been achieved (2.2% before) - one of the highest conversion efficiencies ever achieved. In the frame of this work, two separate experiments at the TRIDENT laser system have shown that these laser-accelerated proton beams, with their high number of particles in a short pulse duration, are well-suited for creating isochorically heated matter in extreme conditions. Besides the manipulation of the proton beam parameters directly during the generation, the primary aim of this thesis was the capture, control and transport of laser-accelerated proton beams by a solenoidal magnetic field lense for further purpose. In a joint project proposal, the laser and

  11. Laser-accelerated proton beams as a new particle source

    International Nuclear Information System (INIS)

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. In this work, an experimental method to fully reconstruct laser-accelerated proton beam parameters, called radiochromic film imaging spectroscopy (RIS), was developed. Since the proton beam expansion is a plasma expansion with accompanying electrons, a low-energy electron spectrometer was developed, built and tested to study the electron distribution matching to the proton beam energy distribution. Two experiments were carried out at the VULCAN Petawatt laser with the aim of showing dynamic control and enhancement of proton acceleration using multiple or defocused laser pulses. Irradiating the target with a long pulse, low-intensity laser (1012 W/cm2) prior to the main pulse (∝ns), an optimum pre-plasma density scale length of 60 μm is generated leading to an enhancement of the maximum proton energy (∝25%), the proton flux (factor of 3) and the beam uniformity. Proton beams were generated more efficiently than previously by driving thinner target foils at a lower intensity over a large area. The optimum condition was a 2 μm foil irradiated with an intensity of 1019 W/cm2 onto a 60 μm spot. Laser to proton beam efficiencies of 7.8% have been achieved (2.2% before) - one of the highest conversion efficiencies ever achieved. In the frame of this work, two separate experiments at the TRIDENT laser system have shown that these laser-accelerated proton beams, with their high number of particles in a short pulse duration, are well-suited for creating isochorically heated matter in extreme conditions. Besides the manipulation of the proton beam parameters directly during the generation, the primary aim of this thesis was the capture, control and transport of laser-accelerated proton beams by a solenoidal magnetic field lense for further purpose. In a joint project proposal, the laser and plasma physics group of the Technische Universitat Darmstadt

  12. Development of underwater laser beam welding equipment

    International Nuclear Information System (INIS)

    Toshiba has developed various laser-based maintenance and repair technologies and already applied to nuclear power plants. Laser beam welding technology has been developed as an SCC countermeasure for aged components in PWRs and BWRs. This technology can also be used underwater by blowing shielding gas for creating a local dry area. This welding equipment has damage detecting function of optical elements such as windows and optical fiber cables, and the laser beam spot position and diameter can be adjusted. These designs have improved safety and welding quality. In this report, the outline of the underwater laser beam welding for Reactor Coolant System nozzles of PWRs are presented, especially focused on the device configurations. (author)

  13. Synchronous characterization of semiconductor microcavity laser beam.

    Science.gov (United States)

    Wang, T; Lippi, G L

    2015-06-01

    We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam's tails deviations from the Gaussian shape, however, are accompanied by sizeable fluctuations in the laser wavelength, possibly deriving from manufacturing details and from the influence of spontaneous emission in the very low intensity wings. In addition to the synchronous spatial characterization, a temporal analysis at any given point in the beam cross section is carried out. Using this method, the beam homogeneity and spatial shape, energy density, energy center, and the defects-related spectrum can also be extracted from these high-resolution pictures. PMID:26133832

  14. Synchronous Characterization of Semiconductor Microcavity Laser Beam

    CERN Document Server

    Wang, Tao

    2015-01-01

    We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam's tails deviations from the Gaussian shape, however, are accompanied by sizeable fluctuations in the laser wavelength, possibly deriving from manufacturing details and from the influence of spontaneous emission in the very low intensity wings. In addition to the synchronous spatial characterization, a temporal analysis at any given point in the beam cross-section is carried out. Using this method, the beam homogeneity and spatial shape, energy density, energy center and the defects-related spectrum can also be extracted from these high-resolution pictures.

  15. Collimation of laser-produced proton beam

    Science.gov (United States)

    Takano, M.; Nagashima, T.; Izumiyama, T.; Gu, Y. J.; Barada, D.; Kong, Q.; Wang, P. X.; Ma, Y. Y.; Wang, W. M.; Kawata, S.

    2016-03-01

    In intense laser plasma interaction for particle acceleration several issues remain to be solved. In this paper we focus on a collimation of ion beam, which is produced by a laser plasma interaction. In this study, the ion beam is collimated by a thin film target. When an intense short pulse laser illuminates a target, target electrons are accelerated, and create an electron cloud that generates a sheath electric field at the target surface. Such the ion acceleration mechanism is called the target normal sheath acceleration (TNSA). The TNSA field would be used for the ion beam collimation by the electric field. We have successfully obtained a collimated beam in our particle-in-cell simulations.

  16. Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

    OpenAIRE

    Javis Anyangwe Nwaboh; Thibault Desbois; Daniele Romanini; Detlef Schiel; Olav Werhahn

    2011-01-01

    We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM) method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS), quantum cascade laser absorption spectroscopy (QCLAS), and cavity ring down spectroscopy (CRDS), all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are ...

  17. Collisional dependence of polarization spectroscopy with a picosecond laser

    International Nuclear Information System (INIS)

    The collisional dependence of polarization spectroscopy (PS) with a picosecond-pulse laser is investigated theoretically with a perturbative treatment and experimentally by probing hydroxyl (OH) in a flow cell with a buffer gas of argon. Using a frequency-doubled distributed-feedback dye laser (DFDL), the PS signal strength is monitored as a function of pressure using a nonsaturating pump beam and a saturating pump beam. The collisional dependence of the PS signal is found to decrease significantly with a saturating pump beam. Increasing the flow-cell pressure by a factor of 50 (from 10 torr to 500 torr), the PS signal strength produced with a nonsaturating pump beam decreases by a factor of 18 while that produced with a saturating pump decreases by only a factor of 3. A third-order perturbative (weak-field) approach is used to develop an analytical expression for the PS signal generated by single-mode, exponentially decaying laser pulses. This expression correctly predicts the experimental results acquired with the nonsaturating pump beam. The analytical solution is used to examine the effects of pulse length on the collisional dependence of the weak-field PS signal strength. Results are also presented for a numerical simulation of the time-dependent density matrix equations for the high intensity case. (c) 2000 American Institute of Physics

  18. Electron beam, laser beam and plasma arc welding studies

    Science.gov (United States)

    Banas, C. M.

    1974-01-01

    This program was undertaken as an initial step in establishing an evaluation framework which would permit a priori selection of advanced welding processes for specific applications. To this end, a direct comparison of laser beam, electron beam and arc welding of Ti-6Al-4V alloy was undertaken. Ti-6Al-4V was selected for use in view of its established welding characteristics and its importance in aerospace applications.

  19. Evaluation of bone tissue reaction in laser beamed implants

    Energy Technology Data Exchange (ETDEWEB)

    Allegrini, Sergio, E-mail: sergiojr@usp.br [Graduate Program in Biodentistry, Ibirapuera University (UNIB), São Paulo, SP, 04661 100 (Brazil); Yoshimoto, Marcelo [Graduate Program in Biodentistry, Ibirapuera University (UNIB), São Paulo, SP, 04661 100 (Brazil); Salles, Marcos Barbosa [Department of Oral and Maxillofacial Surgery, Nove de Julho University (UNINOVE), São Paulo, SP, 02117 010 (Brazil); Allegrini, Marcia Rivellino Facci [São Paulo Fire Department (SPFD) of the Militar Police, Dentistry Section, São Paulo, SP, 01018 001 (Brazil); Pistarini, Luciana Crepaldi Yazawa; Braga, Francisco Jose Correa; Bressiani, Ana Helena de Almeida [Nuclear and Energy Research Institute – IPEN/USP, São Paulo, SP, 05508 900 (Brazil)

    2014-07-01

    The purpose of this study was to evaluate alterations and bone tissue response on laser treated implant surfaces (Nd:YAG – 100 W). Sixty grade II titanium (ASTM F67) mini-implants (1.5 mm × 4.0 mm) were installed in femurs of 30 Wistar rats. The animals were divided into two groups: thirty mini-implants were machined elements (Machined Group) and the other thirty had laser beamed surfaces (Laser Group). The animals were subdivided into three groups, according to bone healing periods of 15, 30 and 60 days. The samples were analyzed under light, scanning electron and confocal 3D microscopy as well as by EDS (energy dispersive spectroscopy) and Student's t test was used for statistical analyses. Light microscopy results showed new bone trabeculae formation toward laser-treated implants at 15 days’ bone repair as well as thin layers of osteoid matrix, indicating high biocompatibility. Similar features were observed in the Machined Group but only after 30 days. Bone/implant contact was better evidenced on laser-treated surfaces compared to that on simply machined implants. The only group that demonstrated change in level of significance was the laser-treated group at the 15-day-healing period (p < 0.05). Higher oxygen concentration possibly provides more efficient response of osteoblasts during new bone tissue deposition. Implant treated surfaces altered by laser beaming, their composition, surface topography and surface energy may be the future scene in implant dentistry.

  20. Evaluation of bone tissue reaction in laser beamed implants

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate alterations and bone tissue response on laser treated implant surfaces (Nd:YAG – 100 W). Sixty grade II titanium (ASTM F67) mini-implants (1.5 mm × 4.0 mm) were installed in femurs of 30 Wistar rats. The animals were divided into two groups: thirty mini-implants were machined elements (Machined Group) and the other thirty had laser beamed surfaces (Laser Group). The animals were subdivided into three groups, according to bone healing periods of 15, 30 and 60 days. The samples were analyzed under light, scanning electron and confocal 3D microscopy as well as by EDS (energy dispersive spectroscopy) and Student's t test was used for statistical analyses. Light microscopy results showed new bone trabeculae formation toward laser-treated implants at 15 days’ bone repair as well as thin layers of osteoid matrix, indicating high biocompatibility. Similar features were observed in the Machined Group but only after 30 days. Bone/implant contact was better evidenced on laser-treated surfaces compared to that on simply machined implants. The only group that demonstrated change in level of significance was the laser-treated group at the 15-day-healing period (p < 0.05). Higher oxygen concentration possibly provides more efficient response of osteoblasts during new bone tissue deposition. Implant treated surfaces altered by laser beaming, their composition, surface topography and surface energy may be the future scene in implant dentistry.

  1. Laser spectroscopy of thermal plasma

    International Nuclear Information System (INIS)

    Thermal plasma, due to its applications, is a research field of great importance, but reliable diagnostics of such plasma remains a challenging task. Spatially resolved methods, which provide local values of plasma parameters, are crucial for understanding the underlying physics. This can be achieved using pump–probe techniques. Two methods applicable and useful for thermal plasma diagnostics—four-wave mixing and scattering of laser beams—are discussed in this paper. Experimental examples of their application, namely four-wave mixing in argon arc plasma and scattering of laser light by laser-induced plasma, are presented. (paper)

  2. Laser driver beam combination for fast ignition

    International Nuclear Information System (INIS)

    Based on the estimated parameters of fast ignition,the requirements for laser-beam power intensity and energy are used to analyze the possibility of realizing fast ignition by coherent combination and non-coherent combination. The practical distorted wavefront is considered to analyze the far-field focal spot. Non-coherent combination needs more beams for energy requirement and to limit angle drifting in ±2 μrad through improving laser driver's stability. Coherent combination is beneficial for achieving smaller focal spot and higher power intensity, simultaneously reducing the requirement of energy, but single beam wavefront correction can not improve the power intensity in this method, which leads to combined wavefront correction of the total clear aperture with complex monitoring and control methods. Based on the requirement of parameters and wavefront correction capability, non-coherent beam combination is easier to achieve for fast ignition, however, coherent beam combination has the potential for extensive application. (authors)

  3. Photon Correlation Spectroscopy for Observing Natural Lasers

    CERN Document Server

    Dravins, Dainis

    2007-01-01

    Natural laser emission may be produced whenever suitable atomic energy levels become overpopulated. Strong evidence for laser emission exists in astronomical sources such as Eta Carinae, and other luminous stars. However, the evidence is indirect in that the laser lines have not yet been spectrally resolved. The lines are theoretically estimated to be extremely narrow, requiring spectral resolutions very much higher (R approx.= 10**8) than possible with ordinary spectroscopy. Such can be attained with photon-correlation spectroscopy on nanosecond timescales, measuring the autocorrelation function of photon arrival times to obtain the coherence time of light, and thus the spectral linewidth. A particular advantage is the insensitivity to spectral, spatial, and temporal shifts of emission-line components due to local velocities and probable variability of 'hot-spots' in the source. A laboratory experiment has been set up, simulating telescopic observations of cosmic laser emission. Numerically simulated observa...

  4. Initial alignment method for free space optics laser beam

    Science.gov (United States)

    Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi

    2016-08-01

    The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.

  5. Principles of laser spectroscopy and quantum optics

    CERN Document Server

    Berman, Paul R

    2011-01-01

    Principles of Laser Spectroscopy and Quantum Optics is an essential textbook for graduate students studying the interaction of optical fields with atoms. It also serves as an ideal reference text for researchers working in the fields of laser spectroscopy and quantum optics. The book provides a rigorous introduction to the prototypical problems of radiation fields interacting with two- and three-level atomic systems. It examines the interaction of radiation with both atomic vapors and condensed matter systems, the density matrix and the Bloch vector, and applications involving linear absorptio

  6. Digital Controller For Laser-Beam-Steering Subsystem: Part 2

    Science.gov (United States)

    Ansari, Homayoon; Voisinet, Leeann

    1995-01-01

    A report presents additional information about laser-beam-steering apparatus described in "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193) and "More About Beam-Steering Subsystem for Laser Communication" (NPO-19381). Reiterates basic principles of operation of beam-steering subsystem, with emphasis on modes of operation, basic design concepts, and initial experiments on partial prototype of apparatus.

  7. Gamma spectroscopy: from steady beams to radioactive beams

    International Nuclear Information System (INIS)

    The author gives an overview of his research works in the field of gamma spectroscopy. First, he recalls some results of experiments performed for the study of peculiar structures associated with different modes of nucleus rotation, and notably in the case of collective rotation of deformed and even super-deformed nuclei. Then, he details tools and methods used to experimentally determine the level scheme. The main characteristics of steady and radioactive beams are briefly presented, and their complementarities and differences are highlighted. Specific spectrometers and sensors are described. In a last chapter, the author discusses several research projects he is involved in, and more particularly the 'gamma tracking' which is the fundamental principle for gamma multi-sensors of the next generations

  8. Method and apparatus for laser-controlled proton beam radiology

    Science.gov (United States)

    Johnstone, Carol J.

    1998-01-01

    A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

  9. Reduction of power fluctuation of laser light for collinear laser spectroscopy experiments at BECOLA facility at NSCL

    Science.gov (United States)

    Strum, Ryan; Barquest, Brad; Bollen, Georg; Miniamisono, Kei; Tarazona, David; Klose, Andrew; Mantica, Paul; Morrissey, Dave; Hughes, Max; Ringle, Ryan; Rodriguez, Alberto; Rossi, Dominic; Ryder, Caleb; Shwarz, Stefan; Sumithrarachchi, Chandana; Geppert, Cristopher

    2013-10-01

    The BEam COoler and LAser spectroscopy (BECOLA) facility at NSCL/MSU is designed to determine fundamental properties of the atomic nucleus such as the charge radii, nuclear spins and electromagnetic moments. Commissioning tests of BECOLA have been completed using a stable 39K beam produced from an offline ion source. The 39K beam was then cooled and bunched using a radiofrequency cooler and buncher, propagated collinearly with laser light and resulting fluorescence was detected. The laser light that was co-propagated with the beam was transported to the experimental area from a remote laser room via a single-mode optical fiber. Random rotation of the polarization of the laser light led to a large fluctuation in laser power, and hence a poor signal-to-noise ratio for the fluorescence measurement. A laser power controller was introduced to mitigate the power fluctuations. The performance characteristics of the power-stabilization system as well as the collinear laser spectroscopy of the bunched 39K beam will be discussed. This work was supported in part by the National Science Foundation, Grant PHY-11-02511.

  10. Laser beam application with high power fiber lasers

    Science.gov (United States)

    Beyer, Eckhard; Brenner, Berndt; Morgenthal, Lothar

    2007-05-01

    With the new industrial high power fiber lasers we have already stepped into a new generation of laser applications. These lasers are smaller, better, more cost-effective, and offer a processing "on the fly." Of utmost importance is their excellent beam quality which enables us to reduce the size of the focussing head including the scanning mirrors. With the reduced mass of the mirrors we can reach scanning frequencies up to 1.5 kHz and in special configurations up to 4 kHz. Using such mirrors with this high beam quality we can shape the key hole geometry, and thus it is possible to decrease the keyhole spiking, which always occur in the case of deep penetration welding. We can generate very thin and deep welding seams, which we have only experienced with electron beam welding. The excellent beam quality of the fiber lasers offers us a lot of new applications from deep penetration welding to high speed welding. By using beam scanning we are able to easily change the beam and the seam geometry. Furthermore, it is possible to work with this kind of laser from a distance of some meters between focussing/scanning head and the work piece. This technique is called remote processing or processing "on the fly." The excellent beam quality also enables us to cut very precisely, and due to the small cutting widths with a very high speed. In this case the main problem is that the roughness of the cutting edge increases a little bit. One reason for this is that we cannot blow out the mold as easily as we can do it with higher cutting widths. There are also polarized fiber lasers on the market where we can use the Brewster effect for different applications. The presentation will cover some physical basics including different industrial applications.

  11. Laser beam-plasma coupling in laser solenoid plasmas

    International Nuclear Information System (INIS)

    A model has been constructed to analyze the gross beam-plasma interaction in a laser solenoid plasma. The model includes a simple solution for a slab plasma response to a given laser beam, and a solution for axial beam size variations in response to arbitrary axial plasma structure. The two solutions are combined to determine the coupled behavior. Trapping of the focused laser beam where it enters the plasma is a significant problem, but can be achieved by a minimum level of imbedded field in the plasma. If the beam is trapped, it first focuses and then defocuses near the front of the bleaching wave (front of the laser heated plasma). In order to avoid divergence of the beam near the front, it is essential to have a pre-formed favorable density profile in the plasma. Such a condition is probably achieved automatically in the early stages of plasma heating. Several techniques are discussed which can be used to avert unfavorable refractive behavior (catastrophic self-focusing and defocusing)

  12. Laser driven proton acceleration and beam shaping

    OpenAIRE

    Sinigardi, Stefano

    2014-01-01

    In the race to obtain protons with higher energies, using more compact systems at the same time, laser-driven plasma accelerators are becoming an interesting possibility. But for now, only beams with extremely broad energy spectra and high divergence have been produced. The driving line of this PhD thesis was the study and design of a compact system to extract a high quality beam out of the initial bunch of protons produced by the interaction of a laser pulse with a thin solid target, usi...

  13. Laser spectroscopy and dynamics of transient species

    Energy Technology Data Exchange (ETDEWEB)

    Clouthier, D.J. [Univ. of Kentucky, Lexington (United States)

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  14. Laser schlieren microphone for optoacoustic spectroscopy.

    Science.gov (United States)

    Choi, J G; Diebold, G J

    1982-11-15

    This paper describes a laser schlieren microphone, where a low-power He-Ne laser beam is deflected by a reflecting diaphragm mounted on an optoacoustic Helmholtz resonator. The sinusoidal pressure variations in the resonator distort the surface of the diaphragm so that the reflected laser beam is alternately focused and defocused. The deflection is converted into an amplitude modulation of the beam by an iris located at a distance from the resonator and detected with a photodiode. The light beam can be modulated at a high frequency and the signal from the photodiode processed with a lock-in amplifier so that noise with a power spectral density proportional to the inverse of the frequency is significantly reduced in the final optoacoustic signal. A mathematical description of the laser schlieren microphone is given that shows the system to respond linearly to small signals. An experiment was done to determine the range of linear response of the microphone to large amplitude optoacoustic signals. PMID:20401014

  15. Poly articulated robot with integrated laser beam

    International Nuclear Information System (INIS)

    The ROLD program is born by association of two concepts: an articulated hollow system at five axis, sufficiently thin to be introduced in the standard aperture of a hot cell, the integration of a power CO2 laser beam in the manipulator arm, capable to execute properly the cutting up of a metallic structures. In this paper we present the main characteristics of the robot and laser proceeding and the lessons of an introducing test in a mock up

  16. BaH molecular spectroscopy with relevance to laser cooling

    Science.gov (United States)

    Tarallo, M. G.; Iwata, G. Z.; Zelevinsky, T.

    2016-03-01

    We describe a simple experimental apparatus for laser ablation of barium monohydride (BaH) molecules and the study of their rovibrational spectra relevant to direct laser cooling. BaH is a promising candidate for laser cooling and ultracold fragmentation, both of which are precursors to novel experiments in many-body physics and precision measurement. We present a detailed analysis of the properties of ablation plumes that can improve the understanding of surface ablation and deposition technologies. A range of absorption spectroscopy and collisional thermalization regimes has been studied. We directly measured the Franck-Condon factor of the B 2Σ+(v'=0 ) ←X 2Σ+(v''=1 ) cycling transition. Prospects for production of a high luminosity cryogenic BaH beam are outlined.

  17. BaH molecular spectroscopy with relevance to laser cooling

    CERN Document Server

    Tarallo, M G; Zelevinsky, T

    2015-01-01

    We describe a simple experimental apparatus for laser ablation of barium monohydride (BaH) molecules and the study of their rovibrational spectra that are relevant to direct laser cooling. We present a detailed analysis of the properties of ablation plumes that can improve the understanding of surface ablation and deposition technologies. A range of absorption spectroscopy and collisional thermalization regimes has been studied. We directly measured the Franck-Condon factor of the $\\mathrm{B}^2\\Sigma^+(v'=0)\\leftarrow\\mathrm{X}^2\\Sigma^+(v"=1)$ transition. Prospects for production of a high luminosity cryogenic BaH beam are outlined. This molecule is a promising candidate for laser cooling and ultracold fragmentation, both of which are precursors to novel experiments in many-body physics and precision measurement.

  18. Laser spectroscopy of fission fragments

    International Nuclear Information System (INIS)

    The study of the nuclear structure of fission fragments is discussed. They are neutron-rich nuclei the structure of which possesses some peculiarities. Two regions of fission fragments are discussed: near the shell closures N = 50 and N = 82 and at the boundary of the deformation. A view on the optical properties of these elements is presented and different laser spectroscopic methods for their investigation are proposed. (author)

  19. Laser photoelectron spectroscopy of ions

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, G.B. [Univ. of Colorado, Boulder (United States)

    1993-12-01

    During the last year the author has (a) completed a review article that critically contrasts three methods to measure R-H bond energies, (b) finished a spectroscopic study of the phenylnitrene anion, and (c) successfully completed an overhaul of the light source of the photodetachment spectrometer. The new light source is based on an Ar III laser that provides approximately 100 W of 3.531 eV photons.

  20. Beam shaping for laser initiated optical primers

    Science.gov (United States)

    Lizotte, Todd E.

    2008-08-01

    Remington was one of the first firearm manufacturing companies to file a patent for laser initiated firearms, in 1969. Nearly 40 years later, the development of laser initiated firearms has not become a mainstream technology in the civilian market. Requiring a battery is definitely a short coming, so it is easy to see how such a concept would be problematic. Having a firearm operate reliably and the delivery of laser energy in an efficient manner to ignite the shock-sensitive explosive primer mixtures is a tall task indeed. There has been considerable research on optical element based methods of transferring or compressing laser energy to ignite primer charges, including windows, laser chip primers and various lens shaped windows to focus the laser energy. The focusing of laser light needs to achieve igniting temperatures upwards of >400°C. Many of the patent filings covering this type of technology discuss simple approaches where a single point of light might be sufficient to perform this task. Alternatively a multi-point method might provide better performance, especially for mission critical applications, such as precision military firearms. This paper covers initial design and performance test of the laser beam shaping optics to create simultaneous multiple point ignition locations and a circumferential intense ring for igniting primer charge compounds. A simple initial test of the ring beam shaping technique was evaluated on a standard large caliber primer to determine its effectiveness on igniting the primer material. Several tests were conducted to gauge the feasibility of laser beam shaping, including optic fabrication and mounting on a cartridge, optic durability and functional ignition performance. Initial data will be presented, including testing of optically elements and empirical primer ignition / burn analysis.

  1. Laser synchrotron radiation and beam cooling

    Energy Technology Data Exchange (ETDEWEB)

    Esarey, E.; Sprangle, P.; Ting, A. [Naval Research Lab., Washington, DC (United States)] [and others

    1995-12-31

    The interaction of intense {approx_gt} 10{sup 18} W/cm{sup 2}, short pulse ({approx_lt} 1 ps) lasers with electron beams and plasmas can lead to the generation of harmonic radiation by several mechanisms. Laser synchrotron radiation may provide a practical method for generating tunable, near monochromatic, well collimated, short pulse x-rays in compact, relatively inexpensive source. The mechanism for the generation of laser synchrotron radiation is nonlinear Thomson scattering. Short wavelengths can be generated via Thomson scattering by two methods, (i) backscattering from relativistic electron beams, in which the radiation frequency is upshifted by the relativistic factor 4{gamma}{sup 2}, and (ii) harmonic scattering, in which a multitude of harmonics are generated with harmonic numbers extending out to the critical harmonic number nc{approx_equal}a{sub 0}{sup 3} {much_gt} 1, where a{sub 0} {approx_equal}10{sup -9}{lambda}I{sup 1/2}, {lambda} is the laser wavelength in {mu}m and I is the laser intensity in W/cm{sup 2}. Laser synchrotron sources are capable of generating short ({approx_lt} ps) x-ray pulses with high peak flux ({approx_gt} 10{sup 21} photons/s) and brightness ({approx_gt}{sup 19} photons/s-mm{sup 2}-mrad{sup 2} 0.1%BW. As the electron beam radiates via Thomson scattering, it can subsequently be cooled, i.e., the beam emittance and energy spread can be reduced. This cooling can occur on rapid ({approximately} ps) time scales. In addition, electron distributions with sufficiently small axial energy spreads can be used to generate coherent XUV radiation via a laser-pumped FEL mechanism.

  2. On a laser beam fiducial line application for metrological purposes

    International Nuclear Information System (INIS)

    The possibility of a collimated one-mode laser beam used as a fiducial line is considered. The technology of an 'extended' laser beam formation and application for a much extended fiducial line is proposed

  3. Laser beam propagation in atmospheric turbulence

    Science.gov (United States)

    Murty, S. S. R.

    1979-01-01

    The optical effects of atmospheric turbulence on the propagation of low power laser beams are reviewed in this paper. The optical effects are produced by the temperature fluctuations which result in fluctuations of the refractive index of air. The commonly-used models of index-of-refraction fluctuations are presented. Laser beams experience fluctuations of beam size, beam position, and intensity distribution within the beam due to refractive turbulence. Some of the observed effects are qualitatively explained by treating the turbulent atmosphere as a collection of moving gaseous lenses of various sizes. Analytical results and experimental verifications of the variance, covariance and probability distribution of intensity fluctuations in weak turbulence are presented. For stronger turbulence, a saturation of the optical scintillations is observed. The saturation of scintillations involves a progressive break-up of the beam into multiple patches; the beam loses some of its lateral coherence. Heterodyne systems operating in a turbulent atmosphere experience a loss of heterodyne signal due to the destruction of coherence.

  4. Laser spectroscopy of hydrocarbon radicals

    Energy Technology Data Exchange (ETDEWEB)

    Chen, P. [Harvard Univ., Cambridge, MA (United States)

    1993-12-01

    The author reports the application of supersonic jet flash pyrolysis to the specific preparation of a range of organic radicals, biradicals, and carbenes in a skimmed molecular beam. Each species was produced cleanly and specifically, with little or no secondary reactions by the thermal dissociation of appropriately designed and synthesized organic precursors. Photoelectron spectra of the three isomeric C{sub 3}H{sub 2} carbenes, ortho-benzyne, and the {alpha},3-dehydrotoluene biradical, were used to establish adiabatic ionization potentials for use in thermochemical determinations.

  5. Laser beams: knotted threads of darkness

    OpenAIRE

    Leach, Jonathan; Dennis, Mark R.; Courtial, Johannes; Padgett, Miles J.

    2004-01-01

    Destructive interference may lead to complete cancellation when light waves travelling in different directions cross, and in three-dimensional space this occurs along lines that are vortices of electromagnetic energy flow. Here we confirm theoretical predictions by experimentally creating combinations of optical laser beams in which these dark threads form stable loops that are linked and knotted.

  6. Systems analysis on laser beamed power

    Science.gov (United States)

    Zeiders, Glenn W., Jr.

    1993-01-01

    The NASA SELENE power beaming program is intended to supply cost-effective power to space assets via Earth-based lasers and active optics systems. Key elements of the program are analyzed, the overall effort is reviewed, and recommendations are presented.

  7. More About Beam-Steering Subsystem For Laser Communication

    Science.gov (United States)

    Page, Norman A.; Chen, Chien-Chu; Hemmati, Hamid; Lesh, James R.

    1995-01-01

    Two reports present additional information about developmental beam-steering subsystem of laser-communication system. Aspects of this subsystem described previously in "Beam-Steering Subsystem for Laser Communication" (NPO-19069) and "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193). Reports reiterate basic principles of operation of beam-steering subsystem and of laser-communication system as whole. Also presents some of details of optical and mechanical design of prototype of subsystem, called Optical Communication Demonstrator.

  8. Coherent beam combiner for a high power laser

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd A.

    2002-01-01

    A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

  9. Laser assisted nuclear decay spectroscopy: A new method for studying neutron-deficient francium

    CERN Document Server

    Lynch, Kara Marie

    2015-01-01

    Radioactive decay studies of rare isotopes produced at radioactive ion beam facilities have often been hindered by the presence of isobaric and isomeric contamination. The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN uses laser radiation to stepwise excite and ionize an atomic beam in a particular isomeric state. Deflection of this selectively ionized beam of exotic nuclei, from the remaining neutral contaminants, allows ultra-sensitive detection of rare isotopes and nuclear structure measurements in background-free conditions.\

  10. Safe Laser Beam Propagation for Interplanetary Links

    Science.gov (United States)

    Wilson, Keith E.

    2011-01-01

    Ground-to-space laser uplinks to Earth–orbiting satellites and deep space probes serve both as a beacon and an uplink command channel for deep space probes and Earth-orbiting satellites. An acquisition and tracking point design to support a high bandwidth downlink from a 20-cm optical terminal on an orbiting Mars spacecraft typically calls for 2.5 kW of 1030-nm uplink optical power in 40 micro-radians divergent beams.2 The NOHD (nominal ocular hazard distance) of the 1030nm uplink is in excess of 2E5 km, approximately half the distance to the moon. Recognizing the possible threat of high power laser uplinks to the flying public and to sensitive Earth-orbiting satellites, JPL developed a three-tiered system at its Optical Communications Telescope Laboratory (OCTL) to ensure safe laser beam propagation through navigational and near-Earth space.

  11. Laser spectroscopy of muonic deuterium

    Science.gov (United States)

    Pohl, Randolf; Nez, François; Fernandes, Luis M. P.; Amaro, Fernando D.; Biraben, François; Cardoso, João M. R.; Covita, Daniel S.; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Giesen, Adolf; Gouvea, Andrea L.; Graf, Thomas; Hänsch, Theodor W.; Indelicato, Paul; Julien, Lucile; Knowles, Paul; Kottmann, Franz; Le Bigot, Eric-Olivier; Liu, Yi-Wei; Lopes, José A. M.; Ludhova, Livia; Monteiro, Cristina M. B.; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; dos Santos, Joaquim M. F.; Schaller, Lukas A.; Schuhmann, Karsten; Schwob, Catherine; Taqqu, David; Veloso, João F. C. A.; Antognini, Aldo

    2016-08-01

    The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ–. We measured three 2S-2P transitions in μd and obtain rd = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value rd = 2.1424(21) fm. The μd value is also 3.5σ smaller than the rd value from electronic deuterium spectroscopy. The smaller rd, when combined with the electronic isotope shift, yields a “small” proton radius rp, similar to the one from muonic hydrogen, amplifying the proton radius puzzle.

  12. Biostimulative Effect Of Laser Beams

    Science.gov (United States)

    Mester, E.

    1981-05-01

    We report on experiences gained in healing clinical cases treated with He-Ne and Argon-laser grouped according to etiology. In order to elucidate the action mechanism of the bioregulatory process, the following experiments were carried out: 1. Serial electron-microscopic and radioactivity studies of samples obtained from human ulcers; 2. Chemical transfer of stimulating substrate on human leukocyte population; 3. Enzyme histochemical studies in experiments on rats; 4. Study of vascularization with the "ear chamber" technique carried out on rabbit's ear; 5. The increase of tensile strength in rats; 6. Biochemical demonstration of the RNA, DNA, albumin synthesis on human fibrocyte-cultures; 7.a, 7.b, Immunological studies; 8. Prostaglandin producing effect. The discovery of laser opened up new prospects in the field of the biological research and medical use.

  13. Time-resolved laser spectroscopy in the UV/VUV spectral region

    International Nuclear Information System (INIS)

    Radiative lifetimes ranging from 3 to 500 ns were measured on various states of Ag, N, Se, Te and As, by recording the fluorescence light decay after excitation by a laser pulse. Ag was supplied by a collimated atomic beam while Se, Te and As were contained in quartz cells. Pulsed laser radiation, with a wavelength down to 185 nm, was generated by different set-ups, using Nd-YAG pumped dye lasers combined with non-linear crystals and Raman shifting. Short laser pulses were produced by a nitrogen laser or a distributed feedback dye laser. Two-photon processes and stepwise excitation were used to populate high-lying levels. Depletion spectroscopy, quantum-beat spectroscopy and optical double resonance spectroscopy were also performed

  14. Laser-cooled bunched ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Schiffer, J.P.; Hangst, J.S.; Nielsen, J.S. [and others

    1995-08-01

    In collaboration with the Arhus group, the laser cooling of a beam bunched by an rf electrode was investigated at the ASTRID storage ring. A single laser is used for unidirectional cooling, since the longitudinal velocity of the beam will undergo {open_quotes}synchrotron oscillations{close_quotes} and the ions are trapped in velocity space. As the cooling proceeds the velocity spread of the beam, as well as the bunch length is measured. The bunch length decreases to the point where it is limited only by the Coulomb repulsion between ions. The measured length is slightly (20-30%) smaller than the calculated limit for a cold beam. This may be the accuracy of the measurement, or may indicate that the beam still has a large transverse temperature so that the longitudinal repulsion is less than would be expected from an absolutely cold beam. Simulations suggest that the coupling between transverse and longitudinal degrees of freedom is strong -- but this issue will have to be resolved by further measurements.

  15. Laser Wire and Beam Position Monitor tests

    CERN Document Server

    Boogert, S T; Lyapin, A; Nevay, L; Snuverink, J

    2013-01-01

    This subtask involved two main activities; Firstly the development and subsequent usage of high resolution beam position monitors (BPM) for the International Linear Collider (ILC) and Compact Linear Collider projects (CLIC); and secondly the development of a laser-wire (LW) transverse beam size measurement systems. This report describes the technical progress achieved at a large-scale test ILC compatible BPM system installed at the Accelerator Test Facility 2 (ATF2). The ATF2 is an energy-scaled demonstration system for the final focus systems required to deliver the particle beams to collision at the ILC and CLIC. The ATF2 cavity beam position monitor system is one of the largest of its kind and rivals systems used at free electron lasers. The ATF2 cavity beam position system has achieved a position resolutionof 250 nm (with signal attuenation) and 27 nm (without attenuation). The BPM system has been used routinely for lattice diagnostics, beam based alignment and wakefield measurements. Extensive experience...

  16. A novel laser beam generator in place at SGll

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Researchers with the State Key Laboratory of High Field Laser Physics, the CAS Shanghai Institute of Optics and Fine Mechanics, have been successful in developing a multifunctional and high-energy laser beam system (also known as the ninth laser beam) at the Shenguang-II Laser Facility (SGII).

  17. Coherent beam combining of high powerfiber lasers: Progress and prospect

    Institute of Scientific and Technical Information of China (English)

    LIU; ZeJin; ZHOU; Pu; XU; XiaoJun; WANG; XiaoLin; MA; YanXing

    2013-01-01

    The recent research progress of coherent beam combining of high power fiber lasers is reviewed. Key technologies like coherently combinable fiber laser, phase control of multiple beams and beam tilling are specially analyzed. Prospects for single coherently combinable high power fiber amplifier, beam tilling and target-in-the-loop control for propagation in real atmosphere are presented.

  18. Laser beam shaping theory and techniques, second edition

    CERN Document Server

    Dickey, Fred M

    2014-01-01

    Laser Beam Shaping: Theory and Techniques addresses the theory and practice of every important technique for lossless beam shaping. Complete with experimental results as well as guidance on when beam shaping is practical and when each technique is appropriate, the Second Edition is updated to reflect significant developments in the field. This authoritative text:Features new chapters on axicon light ring generation systems, laser-beam-splitting (fan-out) gratings, vortex beams, and microlens diffusersDescribes the latest advances in beam profile measurement technology and laser beam shaping using diffractive diffusersContains new material on wavelength dependence, channel integrators, geometrical optics, and optical softwareLaser Beam Shaping: Theory and Techniques, Second Edition not only provides a working understanding of the fundamentals, but also offers insight into the potential application of laser-beam-profile shaping in laser system design.

  19. Low phonon energy Nd:LaF3 channel waveguide lasers fabricated by molecular beam epitaxy

    OpenAIRE

    Bhutta, T.; Chardon, A.M.; Shepherd, D. P.; Daran, E.; Serrano, C.; Munoz-Yague, A.

    2001-01-01

    We report the first fabrication and laser operation of channel waveguides based on LaF3 planar thin films grown by molecular beam epitaxy. To our knowledge, this is the lowest phonon energy dielectric material to have shown guided-wave laser operation to date. A full characterization, in terms of spectroscopy, laser results, and propagation losses, is given for the planar thin films upon which the channel waveguides are based. Two channel-fabrication methods are then described, the first invo...

  20. Laser Spectroscopy of Muonic Atoms and Ions

    CERN Document Server

    Pohl, Randolf; Fernandes, Luis M P; Ahmed, Marwan Abdou; Amaro, Fernando D; Amaro, Pedro; Biraben, François; Cardoso, João M R; Covita, Daniel S; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Franke, Beatrice; Galtier, Sandrine; Giesen, Adolf; Gouvea, Andrea L; Götzfried, Johannes; Graf, Thomas; Hänsch, Theodor W; Hildebrandt, Malte; Indelicato, Paul; Julien, Lucile; Kirch, Klaus; Knecht, Andreas; Knowles, Paul; Kottmann, Franz; Krauth, Julian J; Bigot, Eric-Olivier Le; Liu, Yi-Wei; Lopes, José A M; Ludhova, Livia; Machado, Jorge; Monteiro, Cristina M B; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; Santos, Joaquim M F dos; Santos, José Paulo; Schaller, Lukas A; Schuhmann, Karsten; Schwob, Catherine; Szabo, Csilla I; Taqqu, David; Veloso, João F C A; Voss, Andreas; Weichelt, Birgit; Antognini, Aldo

    2016-01-01

    Laser spectroscopy of the Lamb shift (2S-2P energy difference) in light muonic atoms or ions, in which one negative muon $\\mu^-$ is bound to a nucleus, has been performed. The measurements yield significantly improved values of the root-mean-square charge radii of the nuclei, owing to the large muon mass, which results in a vastly increased muon wave function overlap with the nucleus. The values of the proton and deuteron radii are 10 and 3 times more accurate than the respective CODATA values, but 7 standard deviations smaller. Data on muonic helium-3 and -4 ions is being analyzed and will give new insights. In future, the (magnetic) Zemach radii of the proton and the helium-3 nuclei will be determined from laser spectroscopy of the 1S hyperfine splittings, and the Lamb shifts of muonic Li, Be and B can be used to improve the respective charge radii.

  1. In-source laser spectroscopy of polonium isotopes: From atomic physics to nuclear structure

    CERN Multimedia

    Rothe, S

    2014-01-01

    The Resonance Ionization Laser Ion Source RILIS [1] at the CERN-ISOLDE on-line radioactive ion beam facility is essential for ion beam production for the majority of experiments, but it is also powerful tool for laser spectroscopy of rare isotopes. A series of experiments on in-source laser spectroscopy of polonium isotopes [2, 3] revealed the nuclear ground state properties of 191;211;216;218Po. However, limitations caused by the isobaric background of surface-ionized francium isotopes hindered the study of several neutron rich polonium isotopes. The development of the Laser Ion Source and Trap (LIST) [4] and finally its integration at ISOLDE has led to a dramatic suppression of surface ions. Meanwhile, the RILIS laser spectroscopy capabilities have advanced tremendously. Widely tunable titanium:sapphire (Ti:Sa) lasers were installed to complement the established dye laser system. Along with a new data acquisition system [5], this more versatile laser setup enabled rst ever laser spectroscopy of the radioact...

  2. Laser-cooled continuous ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Schiffer, J.P.; Hangst, J.S.; Nielsen, J.S. [and others

    1995-08-01

    A collaboration with a group in Arhus, Denmark, using their storage ring ASTRID, brought about better understanding of ion beams cooled to very low temperatures. The longitudinal Schottky fluctuation noise signals from a cooled beam were studied. The fluctuation signals are distorted by the effects of space charge as was observed in earlier measurements at other facilities. However, the signal also exhibits previously unobserved coherent components. The ions` velocity distribution, measured by a laser fluorescence technique suggests that the coherence is due to suppression of Landau damping. The observed behavior has important implications for the eventual attainment of a crystalline ion beam in a storage ring. A significant issue is the transverse temperature of the beam -- where no direct diagnostics are available and where molecular dynamics simulations raise interesting questions about equilibrium.

  3. Robust Collimation Control of Laser-Generated Ion Beam

    CERN Document Server

    Kawata, S; Kamiyama, D; Nagashima, T; Barada, D; Gu, Y J; Li, X; Yu, Q; Kong, Q; Wang, P X

    2015-01-01

    The robustness of a structured collimation device is discussed for an intense-laser-produced ion beam. In this paper the ion beam collimation is realized by the solid structured collimation device, which produces the transverse electric field; the electric field contributes to reduce the ion beam transverse velocity and collimate the ion beam. Our 2.5 dimensional particle-in cell simulations demonstrate that the collimation device is rather robust against the changes in the laser parameters and the collimation target sizes. The intense short-pulse lasers are now available, and are used to generate an ion beam. The issues in the laser ion acceleration include an ion beam collimation, ion energy spectrum control, ion production efficiency, ion energy control, ion beam bunching, etc. The laser-produced ion beam tends to expand in the transverse and longitudinal directions during the ion beam propagation. The ion beam collimation is focused in this paper.

  4. Fluorescence correlation spectroscopy in laser gradient field

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fluorescence correlation spectroscopy (FCS) is capable of probing dynamic processes in living biological systems. From photon fluctuation of fluorescing particles which diffuse through a small detection volume, FCS reveals information on the concentration and the structure of the particles, as well as information on microscopic environment.In this note, we study the radiation forces experienced by Rayleigh particles in a laser field in details, and analyze the effects of gradient field on FCS measurements.

  5. Absorption spectroscopy with quantum cascade lasers

    Science.gov (United States)

    Kosterev, A. A.; Curl, R. F.; Tittel, F. K.; Gmachl, C.; Capasso, F.; Sivco, D. L.; Baillargeon, J. N.; Hutchinson, A. L.; Cho, A. Y.

    2001-01-01

    Novel pulsed and cw quantum cascade distributed feedback (QC-DFB) lasers operating near lambda=8 micrometers were used for detection and quantification of trace gases in ambient air by means of sensitive absorption spectroscopy. N2O, 12CH4, 13CH4, and different isotopic species of H2O were detected. Also, a highly selective detection of ethanol vapor in air with a sensitivity of 125 parts per billion by volume (ppb) was demonstrated.

  6. High-resolution laser spectroscopy with the Collinear Resonance Ionisation Spectroscopy (CRIS) experiment at CERN-ISOLDE

    Science.gov (United States)

    Cocolios, T. E.; de Groote, R. P.; Billowes, J.; Bissell, M. L.; Budinčević, I.; Day Goodacre, T.; Farooq-Smith, G. J.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Garcia Ruiz, R. F.; Gins, W.; Heylen, H.; Kron, T.; Li, R.; Lynch, K. M.; Marsh, B. A.; Neyens, G.; Rossel, R. E.; Rothe, S.; Smith, A. J.; Stroke, H. H.; Wendt, K. D. A.; Wilkins, S. G.; Yang, X.

    2016-06-01

    The Collinear Resonance Ionisation Spectroscopy (CRIS) experiment at CERN has achieved high-resolution resonance ionisation laser spectroscopy with a full width at half maximum linewidth of 20(1) MHz for 219,221 Fr, and has measured isotopes as short lived as 5 ms with 214 Fr. This development allows for greater precision in the study of hyperfine structures and isotope shifts, as well as a higher selectivity of single-isotope, even single-isomer, beams. These achievements are linked with the development of a new laser laboratory and new data-acquisition systems.

  7. Are laser-induced beams spin polarized?

    Energy Technology Data Exchange (ETDEWEB)

    Buescher, Markus; Lehrach, Andreas; Raab, Natascha [Institut fuer Kernphysik (IKP), Juelich Center for Hadron Physics (JCHP), Forschungszentrum Juelich (Germany); Engin, Ilhan; Hessan, Mohammad Aziz [RWTH Aachen (Germany); Institut fuer Kernphysik (IKP), Juelich Center for Hadron Physics (JCHP), Forschungszentrum Juelich (Germany); Gibbon, Paul; Karmakar, Anupam [Juelich Supercomputing Center (JSC), Forschungszentrum Juelich (Germany); Toncian, Monika; Toncian, Toma; Willi, Oswald [Institut fuer Laser-Plasma Physik (ILPP), Heinrich Heine Universitaet, Duesseldorf (Germany)

    2011-07-01

    The physics of laser-plasma interactions has undergone dramatic developments in recent years, both experimentally and in the theoretical understanding of high-brightness light and particle sources. However, it is a yet untouched issue whether the laser-generated particle beams are or can be spin-polarized and, thus, whether laser-based polarized sources are conceivable. A first measurement of the degree of polarization of laser-accelerated protons have recently been carried out at the Duesseldorf Arcturus Laser Facility where proton beams of typically 3 MeV were produced in foil targets. The results have been analysed with the help of particle-in-cell simulations to follow the generation of static magnetic field gradients ({proportional_to}100s of Megagauss per micron) in thin foil targets. As a next step, measurements with unpolarized H{sub 2} (for proton acceleration) and {sup 3}He gas (for {sup 3}He ions) are planned and, finally, pre-polarized {sup 3}He will be used.

  8. Arbitrary laser beam propagation in free space

    Science.gov (United States)

    Arpali, Çağlar; Baykal, Yahya; Nakiboğlu, Cem

    2009-08-01

    The propagation of arbitrary laser beams in free space is examined. For this purpose, starting with an incident field of arbitrary field distribution, the intensity at the receiver plane is formulated via Huygens Fresnel diffraction integral. Arbitrary source field profile is produced by decomposing the source into incremental areas (pixels). The received field through the propagation in free space is found by superposing the contributions from all source incremental areas. The proposed method enables us to evaluate the received intensity originating from any type of source field. Using the arbitrary beam excitation, intensity of various laser beams such as cos-Gaussian, cosh-Gaussian, general type beams are checked to be consistent with the already existing results in literature, and the received intensity distributions are obtained for some original arbitrary beam field profiles. Our received intensity formulation for the arbitrary source field profiles presented in this paper can find application in optics communication links, reflection from rough surfaces, optical cryptography and optical imaging systems.

  9. Laser beam propagation in nonlinear optical media

    CERN Document Server

    Guha, Shekhar

    2013-01-01

    ""This is very unique and promises to be an extremely useful guide to a host of workers in the field. They have given a generalized presentation likely to cover most if not all situations to be encountered in the laboratory, yet also highlight several specific examples that clearly illustrate the methods. They have provided an admirable contribution to the community. If someone makes their living by designing lasers, optical parametric oscillators or other devices employing nonlinear crystals, or designing experiments incorporating laser beam propagation through linear or nonlinear media, then

  10. Radiative trapping in intense laser beams

    Science.gov (United States)

    Kirk, J. G.

    2016-08-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron–positron pairs can be optimized by a suitable choice of the intensity ratio.

  11. Radiative trapping in intense laser beams

    CERN Document Server

    Kirk, J G

    2016-01-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron-positron pairs can be optimized by a suitable choice of the intensity ratio.

  12. THERMAL BLOOMING OF HIGH POWER LASER BEAMS

    OpenAIRE

    Philbert, M.; Billard, M.; Fertin, G.; Lefèvre, J.

    1980-01-01

    With a view to better predicting the effects of thermal defocusing within the atmosphere, an experimental simulation set-up has been designed at ONERA. This consists essentially of a vertical airtight cell containing a gas or gas mixture sufficiently absorbing to induce "blooming" of a CO2 laser beam over a distance of about 3 m. A return wind tunnel, integrated within the cell, creates a uniform wind on the beam propagation path ; the wind velocity may be precisely adjusted between 0.1 and 2...

  13. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    CERN Document Server

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  14. Laser Materials and Laser Spectroscopy - A Satellite Meeting of IQEC '88

    Science.gov (United States)

    Wang, Zhijiang; Zhang, Zhiming

    1989-03-01

    Highly Excited Vibrational State * Investigation of the Stark Effect in Xenon Autoionizing Rydberg Series with the Use of Coherent Tunable XUV Radiation * Laser Spectroscopy of Autoionising 5 dnf J = 4.5 Rydberg Series of Ba I * Resonance Photoionization Spectroscopy of Atoms: Autoionization and Highly Excited States of Kr and U * Stark Spectra of Strontium and Calcium Atoms * Observation of Bidirectional Stimulated Radiation at 330 nm, 364 nm and 718 nm with 660 nm Laser Pumping in Sodium Vapour * Study of Molecular Rydberg States and their Discriminations in Na2 * The Measurement of the High Excited Spectra of Samarium by using Stepwise Laser Excitation Method * Product Analysis in the Reaction of the Two-photon Excited Xe(5p56p) States with Freons * Photoionization Spectra of Ca and Sr Atoms above the Classical Field-ionization Threshold * Effect of Medium Background on the Hydrogen Spectrum * Photoemission and Photoelectron Spectra from Autoionizing Atoms in Strong Laser Field * Natural Radiative Lifetime Measurements of High-lying States of Samarium * Two-step Laser Excitation of nf Rydberg States in Neutral Al and Observation of Stark Effect * Measurements of Excited Spectra of the Refractory Metal Elements using Discharge Synchronized with the Laser Pulse * Multiphoton Ionization of Atomic Lead at 1.06μ * Kinetic Processes in the Electron-beam pumped KrF Laser * Laser-induced Fluorescence of Zn2 Excimer * Calculation of Transition Intensity in Heteronuclear Dimer NaK: Comparison with Experiment * Laser-induced Fluorescence of CCl2 Carbene * Study of Multiphoton Ionization Spectrum of Benzene and Two-photon Absorption Cross Section * Dicke Narrowing of N2O Linewidth Perturbed by N2 at 10 μm Band * Polyatomic Molecular Ions Studied by Laser Photodissociation Spectroscopy * Transverse-optically Pumped Ultraviolet S2 Laser * Multiphoton Ionization of Propanal by High Power Laser * UV MPI Mass Spectroscopy and Dynamics of Photodissociation of SO2 * Multiphoton

  15. Fourier transform infrared spectroscopy (FTIR) of laser-irradiated cementum

    Science.gov (United States)

    Rechmann, Peter; White, Joel M.; Cecchini, Silvia C. M.; Hennig, Thomas

    2003-06-01

    Utilizing Fourier Transform Infrared Spectroscopy (FTIR) in specular reflectance mode chemical changes of root cement surfaces due to laser radiation were investigated. A total of 18 samples of root cement were analyzed, six served as controls. In this study laser energies were set to those known for removal of calculus or for disinfection of periodontal pockets. Major changes in organic as well as inorganic components of the cementum were observed following Nd:YAG laser irradiation (wavelength 1064 nm, pulse duration 250 μs, free running, pulse repetition rate 20 Hz, fiber diameter 320 μm, contact mode; Iskra Twinlight, Fontona, Slovenia). Er:YAG laser irradiation (wavelength 2.94 μm, pulse duration 250 μs, free running, pulse repetition rate 6 Hz, focus diameter 620 μm, air water cooling 30 ml/min; Iskra Twinlight, Fontona, Slovenia) significantly reduced the Amid bands due to changes in the organic components. After irradiation with a frequency doubled Alexandrite laser (wavelength 377 nm, pulse duration 200 ns, q-switched, pulse repetition rate 20 Hz, beam diameter 800 μm, contact mode, water cooling 30 ml/min; laboratory prototype) only minimal reductions in the peak intensity of the Amide-II band were detected.

  16. Laser spectroscopy of multi-level doppler broadened atomic system

    International Nuclear Information System (INIS)

    Doppler broadened atomic vapor system can be easily prepared for spectroscopy study than an atomic beam system can be. Vapor cell and hollow cathode discharge lamps are widely used in the experiment. The possibility for observing the trapped state in a Doppler broadened Λ system was examined and confirmed by our early experiment where counter-propagating laser beams are used. For the measurement of the hyperfine structure constants of high-lying levels of heavy elements, we compared the co-propagating and counter-propagating beams in a Doppler broadened ladder systems. It was shown that the counter-propagating beams give a stronger and narrower signal than that from the co-propagating beams. Our treatment also considers the power broadening of the transition. For some photo-ionization experiments, it is necessary to pump two thermally populated levels simultaneously to the higher level and then to the auto-ionizing levels. A technique is proposed to avoid the trapped state and to increase the ionization efficiency.

  17. Underwater laser beam welding of Alloy 690

    International Nuclear Information System (INIS)

    Stress Corrosion Clacking (SCC) has been reported at Alloy 600 welds between nozzles and safe-end in Pressurized Water Reactor (PWR) plant. Alloy 690, which has higher chromium content than Alloy 600, has been applied for cladding on Alloy 600 welds for repairing damaged SCC area. Toshiba has developed Underwater Laser Beam Welding technique. This method can be conducted without draining, so that the repairing period and the radiation exposure during the repair can be dramatically decreased. In some old PWRs, high-sulfur stainless steel is used as the materials for this section. It has a high susceptibility of weld cracks. Therefore, the optimum welding condition of Alloy 690 on the high-sulfur stainless steel was investigated with our Underwater Laser Beam Welding unit. Good cladding layer, without any crack, porosity or lack of fusion, could be obtained. (author)

  18. Beam shaping for laser-based adaptive optics in astronomy

    OpenAIRE

    Béchet, Clémentine; Guesalaga, Andrés; Neichel, Benoit; Fesquet, Vincent; González-Núñez, Héctor; Zúñiga, Sebastián; Escarate, Pedro; Guzman, Dani

    2014-01-01

    The availability and performance of laser-based adaptive optics (AO) systems are strongly dependent on the power and quality of the laser beam before being projected to the sky. Frequent and time-consuming alignment procedures are usually required in the laser systems with free-space optics to optimize the beam. Despite these procedures, significant distortions of the laser beam have been observed during the first two years of operation of the Gemini South multi-conjugate adaptive optics syst...

  19. Fast Laser Cooling of Long Lived Ion Beams

    OpenAIRE

    Bessonov, E. G.; Osipov, A. L.

    2013-01-01

    Some peculiarities of fast laser cooling of long-lived ion beams in storage rings are discussed. Selective interaction of ions and broadband laser beam with sharp frequency and geometric edges is used while laser and ion beams are partially overlapped. The rates of change of the ion beam density in different regions of the phase space and at different moments of time in this scheme of cooling differ. That is why the generalized Robinson theorem valid for the infinitesimal phase space regions ...

  20. Picosecond Laser Chemistry in Supersonic Jet Beams

    OpenAIRE

    Zewail, Ahmed H.

    1983-01-01

    In this review we describe the development and the applications of the picosecond-jet technique, which utilizes a picosecond laser and a supersonically-cold jet beam of large molecules. The applications include studies of coherence (quantum beats), photodissociation, isomerization, and partial solvation. The results emphasize the role of intramolecular energy redistribution, and provide evidence for intramolecular threshold effect for rates vs. excess molecular energy. Simple theory for this ...

  1. Ultrafast laser spectroscopy in complex solid state materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tianqi [Iowa State Univ., Ames, IA (United States)

    2014-12-01

    This thesis summarizes my work on applying the ultrafast laser spectroscopy to the complex solid state materials. It shows that the ultrafast laser pulse can coherently control the material properties in the femtosecond time scale. And the ultrafast laser spectroscopy can be employed as a dynamical method for revealing the fundamental physical problems in the complex material systems.

  2. Group velocity delay spectroscopy technique for industrial monitoring of electron beam induced vapors

    Energy Technology Data Exchange (ETDEWEB)

    Benterou, J J; Berzins, L V; Sharma, M N

    1998-09-24

    Spectroscopic techniques are ideal for characterization and process control of electron beam generated vapor plumes. Absorption based techniques work well for a wide variety of applications, but are difficult to apply to optically dense or opaque vapor plumes. We describe an approach for monitoring optically dense vapor plumes that is based on measuring the group velocity delay of a laser beam near an optical transition to determine the vapor density. This technique has a larger dynamic range than absorption spectroscopy. We describe our progress towards a robust system to monitor aluminum vaporization in an industrial environment. Aluminum was chosen because of its prevalence in high performance aircraft alloys. In these applications, composition control of the alloy constituents is critical to the deposition process. Data is presented demonstrating the superior dynamic range of the measurement. In addition, preliminary data demonstrating aluminum vapor rate control in an electron beam evaporator is presented. Alternative applications where this technique could be useful are discussed. Keywords: Group velocity delay spectroscopy, optical beat signal, optical heterodyne, index of refraction, laser absorption spectroscopy, external cavity diode laser (ECDL), electron beam vaporization, vapor density, vapor phase manufacturing, process control

  3. Laser beam propagation in a long solenoid

    International Nuclear Information System (INIS)

    An analysis of the propagation of a laser beam in a cylindrical magnetically confined plasma with parabolic density profile is presented. The normal modes which are self-trapped are given. It is found that the largest mode that can be trapped by the plasma is given by 1/2 (R02/w2 -- 1) where R0 is the radius of the plasma column and w is the fundamental mode width. It is found that all the trapped modes in a finite plasma can easily propagate distances of the order of one kilometer. An exact solution for the amplitude of the electric field for an incident gaussian beam was obtained. The solution exhibits alternate focusing and defocusing of the beam. The effect of this on the plasma heating is discussed. (U.S.)

  4. Laser stripping of the TRIUMF H- beam

    International Nuclear Information System (INIS)

    A ≤ nA external beam of 50 to 200 MeV is required for certain physics and medical experiments at the same time as 200 μA is being accelerated for meson production. A mode-locked laser, synchronized with the cyclotron rf, can produce a 20 nA parasitic H0 beam for continuous extraction. The best available Nd:YAG or Nd:YLF laser (Av. Pwr. 15 W) mode-locked at a harmonic of the cyclotron rf falls short of the required intensity by a factor of about 50. An optical delay line could trap the mode-locked pulse train to achieve the required intensity. The optical delay line is a near-concentric resonator installed half above and half below the beam plane and in which all trapped pulses cross the midplane in synchronism with the cyclotron beam bunches. An analysis of the delay line is presented in terms of the transfer matrix for one round trip in the periodic focusing system formed by the end mirrors of the resonator. An enhancement factor ≥55 is possible with 80 trapped pulses if the mirror reflectively ≥ 99%

  5. Staging laser plasma accelerators for increased beam energy

    OpenAIRE

    Panasenko, Dmitriy

    2010-01-01

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10m, ...

  6. Sensitive spectroscopy of an ytterbium atomic beam

    CERN Document Server

    Guttridge, A; Kemp, S L; Boddy, D; Freytag, R; Tarbutt, M R; Hinds, E A; Cornish, S L

    2015-01-01

    Experimental studies of ultracold ytterbium atoms generally involve the frequency stabilisation (locking) of lasers to two transitions at 399 and 556 nm in order to implement laser cooling. Here we present a simple and robust apparatus for generation of suitable, narrow fluorescence signals with a high signal to noise ratio at both wavelengths. The design utilises easily acquired vacuum parts, optics and electronics and requires very little laser power. We demonstrate the stability and precision of the frequency stabilisation at 556 nm by presenting sensitive measurements of the gravitational sag of an ytterbium MOT as a function of laser power.

  7. Phasing surface emitting diode laser outputs into a coherent laser beam

    Science.gov (United States)

    Holzrichter, John F.

    2006-10-10

    A system for generating a powerful laser beam includes a first laser element and at least one additional laser element having a rear laser mirror, an output mirror that is 100% reflective at normal incidence and laser material between the rear laser mirror and the output mirror. The system includes an injector, a reference laser beam source, an amplifier and phase conjugater, and a combiner.

  8. Laser Beam Profile Influence on LIBS Analytical Capabilities: Single vs. Multimode Beam

    CERN Document Server

    Lednev, Vasily N; Bunkin, Alexey F

    2013-01-01

    Single vs. multimode laser beams have been compared for laser ablation on steel samples. Laser plasma properties and analytical capabilities (precision, limit of detection) were used as key parameters for comparison. Peak fluence at focal spot has been observed to be higher for Gaussian beam despite ~14-fold lower pulse energy. A comparison of Gaussian and multimode beams with equal energy was carried out in order to estimate influence of beam profile only. Single mode lasing (Gaussian beam) results in better reproducibility of analytical signals compared to multimode lasing while laser energy reproducibility was the same for both cases. Precision improvements were attributed to more stable laser ablation due to better reproducibility of beam profile fluence at laser spot. Plasma temperature and electron density were higher for Gaussian laser beam. Calibration curves were obtained for four elements under study (Cr, Mn, Si, Cu). Two sampling (drilling and scanning procedures) and two optical detection schemes ...

  9. Semiconductor Laser With Two-Dimensional Beam Steering

    Science.gov (United States)

    Katz, J.

    1986-01-01

    Modification of monolithic semiconductor injection laser capable of one-dimensional electronic beam steering enables deflection of beam in second direction. Such laser chip provides beam pointing or raster scanning for applications in optical communications, data processing, image scanning, and optical ranging.

  10. Collaborative Research: Instability and transport of laser beam in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Harvey Arnold [New Mexico Consortium; Lushnikov, Pavel [University of New Mexico

    2014-11-18

    Our goal was to determine the onset of laser light scattering due to plasma wave instabilities. Such scatter is usually regarded as deleterious since laser beam strength is thereby diminished. While this kind of laser-plasma-instability (LPI) has long been understood for the case of coherent laser light, the theory of LPI onset for a laser beam with degraded coherence is recent. Such a laser beam fills plasma with a mottled intensity distribution, which has large fluctuations. The key question is: do the exceptionally large fluctuations control LPI onset or is it controlled by the relatively quiescent background laser intensity? We have answered this question. This is significant because LPI onset power in the former case is typically small compared to that of the latter. In addition, if large laser intensity fluctuations control LPI onset, then nonlinear effects become significant for less powerful laser beams than otherwise estimated.

  11. Isotope analysis by infrared laser absorption spectroscopy

    International Nuclear Information System (INIS)

    The feasibility of IR laser spectroscopy as a technique for the measurement of small abundances of stable and radioactive isotopes has been examined. Theoretical considerations and first experimental results with two laser systems are presented: 1) Coincidences between emission lines of a CO2-laser and absorption lines of 13C-subsituted ethylene can be used to determine the 13C-concentration of C2H4. 2) A tunable PbS-diode laser emitting in the 4.3 μm-spectral region of the rotation-vibration bands of CO2 can be used to determine abundances of 12C, 13C, 16O, 17O and 18O in small samples of CO2. With optimized performance, sensitivities up to 10-9-10-10 seem possible, and for higher abundances an accuracy of 10-3. This should allow geophysical isotope studies to be performed and it is hoped that the technique will eventually be applicable to measuring the activity of long-lived radioisotopes. (orig.)

  12. A novel differential velocity modulation laser spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Experimental investigation of a novel differential velocity modulation laser spectroscopy is reported and demonstrated with the spectra of Meinel system. The S/N ratio excesses 500︰1, about 60 times higher than that with the traditional non-differential technique. With this technique, we obtained the high-resolution electronic absorption spectra of (1, 0) vibration-al band of CS+ for the first time. It is confirmed that this technique will be a powerful method and receive wide application in studies of new molecular ions.

  13. Storage ring and laser nuclear spectroscopy

    International Nuclear Information System (INIS)

    Storage-ring technique is complementary to trapping-ion technique. A storage ring for energetic ions will enable us to study exotic phenomena, such as hydrogenic atoms and enhanced β-decay of 'bare nuclei'. A storage ring for low-energy ions is good for precise laser-nuclear spectroscopy. TARN-II is a kind of the former, and it is suggested that an extremely high magnetic field produced by a highly ionized atom gives us insight into nuclear magnetism if hyperfine anomaly is observed for such an atom. (author)

  14. Efficient laser production of energetic neutral beams

    Science.gov (United States)

    Mollica, F.; Antonelli, L.; Flacco, A.; Braenzel, J.; Vauzour, B.; Folpini, G.; Birindelli, G.; Schnuerer, M.; Batani, D.; Malka, V.

    2016-03-01

    Laser-driven ion acceleration by intense, ultra-short, laser pulse has received increasing attention in recent years, and the availability of much compact and versatile ions sources motivates the study of laser-driven sources of energetic neutral atoms. We demonstrate the production of a neutral and directional beam of hydrogen and carbon atoms up to 200 keV per nucleon, with a peak flow of 2.7× {{10}13} atom s-1. Laser accelerated ions are neutralized in a pulsed, supersonic argon jet with tunable density between 1.5× {{10}17} cm-3and 6× {{10}18} cm-3. The neutralization efficiency has been measured by a time-of-flight detector for different argon densities. An optimum is found, for which complete neutralization occurs. The neutralization rate can be explained only at high areal densities (>1× {{10}17} cm-2) by single electron charge transfer processes. These results suggest a new perspective for the study of neutral production by laser and open discussion of neutralization at a lower density.

  15. Laser beam riding guided system principle and design research

    Science.gov (United States)

    Qu, Zhou; Jin, Yi; Xu, Zhou; Xing, Hao

    2016-01-01

    With the development of science and technology, precision-strike weapons has been considered to be important for winning victory in military field. Laser guidance is a major method to execute precision-strike in modern warfare. At present, the problems of primary stage of Laser guidance has been solved with endeavors of countries. Several technical aspects of laser-beam riding guided system have been mature, such as atmosphere penetration of laser beam, clutter inhibition on ground, laser irradiator, encoding and decoding of laser beam. Further, laser beam quality, equal output power and atmospheric transmission properties are qualified for warfare situation. Riding guidance instrument is a crucial element of Laser-beam riding guided system, and is also a vital element of airborne, vehicle-mounted and individual weapon. The optical system mainly consist of sighting module and laser-beam guided module. Photoelectric detector is the most important sensing device of seeker, and also the key to acquire the coordinate information of target space. Currently, in consideration of the 1.06 u m of wavelength applied in all the semi-active laser guided weapons systems, lithium drifting silicon photodiode which is sensitive to 1.06 u m of wavelength is used in photoelectric detector. Compared to Solid and gas laser, diode laser has many merits such as small volume, simple construction, light weight, long life, low lost and easy modulation. This article introduced the composition and operating principle of Laser-beam riding guided system based on 980 nm diode laser, and made a analysis of key technology; for instance, laser irradiator, modulating disk of component, laser zooming system. Through the use of laser diode, Laser-beam riding guided system is likely to have smaller shape and very light.

  16. Application of reactor-pumped lasers to power beaming

    Science.gov (United States)

    Repetti, T. E.

    1991-10-01

    Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technically or economically competitive with more mature solid-state technologies for application to power beaming.

  17. An all-solid state laser system for the laser ion source RILIS and in-source laser spectroscopy of astatine at ISOLDE, CERN

    CERN Document Server

    Rothe, Sebastian; Nörtershäuser, W

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at ISOLDE, CERN, by the addition of an all-solid state tuneable titanium: sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE, CERN, and at ISAC, TRIUMF, radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  18. An all-solid state laser system for the laser ion sources RILIS and in-source laser spectroscopy of astatine at ISOLDE/CERN

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, Sebastian

    2012-09-24

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  19. An all-solid state laser system for the laser ion sources RILIS and in-source laser spectroscopy of astatine at ISOLDE/CERN

    International Nuclear Information System (INIS)

    This doctoral thesis describes the extension of the resonance ionization laser ion source RILIS at CERN/ISOLDE by the addition of an all-solid state tunable titanium:sapphire (Ti:Sa) laser system to complement the well-established system of dye lasers. Synchronous operation of the so called Dual RILIS system of Ti:Sa and dye lasers was investigated and the potential for increased ion beam intensity, reliability, and reduced setup time has been demonstrated. In-source resonance ionization spectroscopy was performed at ISOLDE/CERN and at ISAC/TRIUMF radioactive ion beam facilities to develop an efficient and selective three-colour ionization scheme for the purely radioactive element astatine. A LabVIEW based monitoring, control and measurement system was conceived which enabled, in conjunction with Dual RILIS operation, the spectroscopy of high lying Rydberg states, from which the ionization potential of the astatine atom was determined for the first time experimentally.

  20. ISOLDE beams of neutron-rich zinc isotopes yields, release, decay spectroscopy

    CERN Document Server

    Köster, U; Clausen, C; Delahaye, P; Fedosseev, V; Fraile-Prieto, L M; Gernhäuser, R; Gilles, T J; Ionan, A; Kröll, T; Mach, H; Marsh, B; Seliverstov, D M; Sieber, T; Siesling, E; Tengborn, E; Wenander, F; Van de Walle, J

    2005-01-01

    Intense radioactive ion beams of the neutron-rich zinc isotopes 69-81Zn have been produced at the isotope on-line facility ISOLDE at CERN. The combined use of spallations-neutron induced fission of 238UC_x targets and resonant laser ionization provided sufficient suppression of disturbing isobars (mainly gallium and rubidium) to perform decay spectroscopy up to 81Zn.

  1. ISOLDE beams of neutron-rich zinc isotopes: yields, release, decay spectroscopy

    International Nuclear Information System (INIS)

    Intense radioactive ion beams of the neutron-rich zinc isotopes 69-81Zn have been produced at the isotope separation on-line facility ISOLDE at CERN. The combined use of spallation-neutron induced fission of 238UCx targets and resonant laser ionization provided sufficient suppression of disturbing isobars (mainly gallium and rubidium) to perform decay spectroscopy up to 81Zn. (authors)

  2. Laser systems configured to output a spectrally-consolidated laser beam and related methods

    Science.gov (United States)

    Koplow, Jeffrey P.

    2012-01-10

    A laser apparatus includes a plurality of pumps each of which is configured to emit a corresponding pump laser beam having a unique peak wavelength. The laser apparatus includes a spectral beam combiner configured to combine the corresponding pump laser beams into a substantially spatially-coherent pump laser beam having a pump spectrum that includes the unique peak wavelengths, and first and second selectively reflective elements spaced from each other to define a lasing cavity including a lasing medium therein. The lasing medium generates a plurality of gain spectra responsive to absorbing the pump laser beam. Each gain spectrum corresponds to a respective one of the unique peak wavelengths of the substantially spatially-coherent pump laser beam and partially overlaps with all other ones of the gain spectra. The reflective elements are configured to promote emission of a laser beam from the lasing medium with a peak wavelength common to each gain spectrum.

  3. Definition and measurement of the beam propagation factor M2 for chromatic laser beams

    Institute of Scientific and Technical Information of China (English)

    Tao Fang; Xin Ye; Jinfu Niu; Jianqiu Xu

    2006-01-01

    The concept of the beam propagation factor M2 is extended for chromatic laser beams. The definition of the beam propagation factor can be generalized with the weighted effective wavelength. Using the new definition of factor M2, the propagation of chromatic beams can be analyzed by the beam propagation factor M2 as same as that of monochromatic beams. A simple method to measure the chromatic beam factor M2 is demonstrated. The chromatic factor M2 is found invariable while the laser beam propagates through the dispersion-free ABCD system.

  4. Measuring the quantum statistics of an atom laser beam

    OpenAIRE

    Bradley, A. S.; Olsen, M. K.; Haine, S. A.; Hope, J. J.

    2006-01-01

    We propose and analyse a scheme for measuring the quadrature statistics of an atom laser beam using extant optical homodyning and Raman atom laser techniques. Reversal of the normal Raman atom laser outcoupling scheme is used to map the quantum statistics of an incoupled beam to an optical probe beam. A multimode model of the spatial propagation dynamics shows that the Raman incoupler gives a clear signal of de Broglie wave quadrature squeezing for both pulsed and continuous inputs. Finally, ...

  5. Propagation of some coherent and partially coherent laser beams

    OpenAIRE

    Cai, Yangjian

    2006-01-01

    In this thesis, we investigate the propagation of some coherent and partially coherent laser beams, including a dark hollow beam (DHB), an elliptical Gaussian beam (EGB), a flat-topped beam and a twisted anisotropic Gaussian Schell-model (TAGSM) beam, through a paraxial optical system or a turbulent atmosphere. Several theoretical models are proposed to describe a DHB of circular or non-circular symmetry. Approximate analytical formulas for a DHB and a partially coherent TAGSM beam propagatin...

  6. Transformation hardening of steel by laser beam

    International Nuclear Information System (INIS)

    A locally fabricated 250 Watts Co/sub 2/ laser has been used to study the surface hardening of steel with different carbon concentrations ranging from 0.17 to 0.6%. The laser beam was defocused to a spot size of 2mm. Preliminary results indicate a more than 2.5 times increases in hardness for the 0.17%, 0.45% and 0.6% carbon steel. The microhardness was found to increase exponentially with increasing concentrations of carbon in steel. The microstructure shows that maximum hardness appears in the region that is transformed to martensite. The results were found to be in excellent agreement with similar works carried out elsewhere. (author)

  7. Processing of scintigrams by laser beams

    International Nuclear Information System (INIS)

    In order to improve the clinical information content of scintigrams, the coherent image produced by means of laser light and the filtering out of certain space frequencies through holographic filters are used. By integral transformations, disturbances such as camera aberration, kinetic unsharpness, 3-dimensional expansion of the organs as well as higher statistics with low impulse number may be suppressed. Particularly with fast changing processes, e.g. in the fast phases of the cerebral and cardial sequence scintiscanning and with perfusion-ventilation studies with xenon 133, image processing is important as is shown by a few examples. Finally, an electronic image processing method under development is referred to in which image scanning takes place by means of a sharp bundled laser beam. (ORU/LH)

  8. Resonant microphone based on laser beam deflection

    Science.gov (United States)

    Roark, Kevin; Diebold, Gerald J.

    2004-07-01

    A microphone consisting of a flexible membrane coupled to a Helmholtz resonator can be constructed to have a resonance at a specific frequency making it, unlike conventional broadband microphones, a frequency selective detector of sound. The present device uses a laser beam reflected from the membrane and directed onto a split photodiode to record the motion of the membrane. Since the microphone has a lightly damped resonance, both the thermal noise fluctuations in the displacement of the membrane from its equilibrium position and the response of the microphone to sound at the resonance frequency are large. The large amplitude of both the signal and the noise fluctuations means that effect of amplifier noise on the microphone's sensitivity is diminished relative to that in broadband microphones. Applications of the microphone include photoacoustic detection of gases employing low power lasers.

  9. Beam shaping in high-power laser systems with using refractive beam shapers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim

    2012-06-01

    Beam Shaping of the spatial (transverse) profile of laser beams is highly desirable by building optical systems of high-power lasers as well in various applications with these lasers. Pumping of the crystals of Ti:Sapphire lasers by the laser radiation with uniform (flattop) intensity profile improves performance of these ultrashort pulse high-power lasers in terms of achievable efficiency, peak-power and stability, output beam profile. Specifications of the solid-state lasers built according to MOPA configuration can be also improved when radiation of the master oscillator is homogenized and then is amplified by the power amplifier. Features of building these high power lasers require that a beam shaping solution should be capable to work with single mode and multimode beams, provide flattop and super-Gauss intensity distributions, the consistency and divergence of a beam after the intensity re-distribution should be conserved and low absorption provided. These specific conditions are perfectly fulfilled by the refractive field mapping beam shapers due to their unique features: almost lossless intensity profile transformation, low output divergence, high transmittance and flatness of output beam profile, extended depth of field, adaptability to real intensity profiles of TEM00 and multimode laser sources. Combining of the refractive field mapping beam shapers with other optical components, like beam-expanders, relay imaging lenses, anamorphic optics makes it possible to generate the laser spots of necessary shape, size and intensity distribution. There are plenty of applications of high-power lasers where beam shaping bring benefits: irradiating photocathode of Free Electron Lasers (FEL), material ablation, micromachining, annealing in display making techniques, cladding, heat treating and others. This paper will describe some design basics of refractive beam shapers of the field mapping type, with emphasis on the features important for building and applications

  10. Single laser beam based passive optical sorter

    Czech Academy of Sciences Publication Activity Database

    Brzobohatý, Oto; Karásek, Vítězslav; Šiler, Martin; Chvátal, Lukáš; Čižmár, T.; Zemánek, Pavel

    Bellingham: SPIE, 2013, 863715:1-8. ISSN 0277-786X. [Conference on Complex Light and Optical Forces /7./ part of Photonics West. San Francisco (US), 05.02.2013-07.02.2013] R&D Projects: GA TA ČR TE01020233; GA ČR GA202/09/0348; GA ČR GPP205/11/P294; GA MŠk LH12018; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : optical trapping * optical sorting * tractor beam * particle delivery Subject RIV: BH - Optics, Masers, Lasers

  11. Ion-beam assisted laser fabrication of sensing plasmonic nanostructures

    Science.gov (United States)

    Kuchmizhak, Aleksandr; Gurbatov, Stanislav; Vitrik, Oleg; Kulchin, Yuri; Milichko, Valentin; Makarov, Sergey; Kudryashov, Sergey

    2016-01-01

    Simple high-performance, two-stage hybrid technique was developed for fabrication of different plasmonic nanostructures, including nanorods, nanorings, as well as more complex structures on glass substrates. In this technique, a thin noble-metal film on a dielectric substrate is irradiated by a single tightly focused nanosecond laser pulse and then the modified region is slowly polished by an accelerated argon ion (Ar+) beam. As a result, each nanosecond laser pulse locally modifies the initial metal film through initiation of fast melting and subsequent hydrodynamic processes, while the following Ar+-ion polishing removes the rest of the film, revealing the hidden topography features and fabricating separate plasmonic structures on the glass substrate. We demonstrate that the shape and lateral size of the resulting functional plasmonic nanostructures depend on the laser pulse energy and metal film thickness, while subsequent Ar+-ion polishing enables to vary height of the resulting nanostructures. Plasmonic properties of the fabricated nanostructures were characterized by dark-field micro-spectroscopy, Raman and photoluminescence measurements performed on single nanofeatures, as well as by supporting numerical calculations of the related electromagnetic near-fields and Purcell factors. The developed simple two-stage technique represents a new step towards direct large-scale laser-induced fabrication of highly ordered arrays of complex plasmonic nanostructures.

  12. Femtosecond Transversal Deflection of Electron Beams with the Help of Laser Beams and Its Possible Applications

    OpenAIRE

    Ispirian, K. A.; Ispiryan, M. K.

    2003-01-01

    It is shown that the interaction of an electron beam with polarized electromagnetic wave of laser photons propagating in the same direction in a short interaction region results in significant transversal deflection of the electrons which can be used for production of femtosecond electron and synchrotron radiation beams, for chopping the electron beams and construction of laser oscilloscopes measuring femtosecond processes.

  13. A practical guide to handling laser diode beams

    CERN Document Server

    Sun, Haiyin

    2015-01-01

    This book offers the reader a practical guide to the control and characterization of laser diode beamsLaser diodes are the most widely used lasers, accounting for 50% of the global laser market.  Correct handling of laser diode beams is the key to the successful use of laser diodes, and this requires an in-depth understanding of their unique properties. Following a short introduction to the working principles of laser diodes, the book describes the basics of laser diode beams and beam propagation, including Zemax modeling of a Gaussian beam propagating through a lens.  The core of the book is concerned with laser diode beam manipulations: collimating and focusing, circularization and astigmatism correction, coupling into a single mode optical fiber, diffractive optics and beam shaping, and manipulation of multi transverse mode beams.  The final chapter of the book covers beam characterization methods, describing the measurement of spatial and spectral properties, including wavelength and linewidth meas...

  14. Laser-Induced Magnetic Dipole Spectroscopy.

    Science.gov (United States)

    Hintze, Christian; Bücker, Dennis; Domingo Köhler, Silvia; Jeschke, Gunnar; Drescher, Malte

    2016-06-16

    Pulse electron paramagnetic resonance measurements of nanometer scale distance distributions have proven highly effective in structural studies. They exploit the magnetic dipole-dipole coupling between spin labels site-specifically attached to macromolecules. The most commonly applied technique is double electron-electron resonance (DEER, also called pulsed electron double resonance (PELDOR)). Here we present the new technique of laser-induced magnetic dipole (LaserIMD) spectroscopy based on optical switching of the dipole-dipole coupling. In a proof of concept experiment on a model peptide, we find, already at a low quantum yield of triplet excitation, the same sensitivity for measuring the distance between a porphyrin and a nitroxide label as in a DEER measurement between two nitroxide labels. On the heme protein cytochrome C, we demonstrate that LaserIMD allows for distance measurements between a heme prosthetic group and a nitroxide label, although the heme triplet state is not directly observable by an electron spin echo. PMID:27163749

  15. Adaptive feedback beam shaping of the CO2 welding laser

    Czech Academy of Sciences Publication Activity Database

    Jedlička, Petr; Mrňa, L.; Šarbort, M.; Řeřucha, Šimon

    Bellingham: SPIE, 2010, 77890V: 1-8. ISBN 978-0-8194-8285-3. [Laser Beam Shaping XI. San Diego (US), 02.08.2010] R&D Projects: GA MPO 2A-3TP1/113 Institutional research plan: CEZ:AV0Z20650511 Keywords : laser beam welding * adaptive optics * laser welding control * light emission monitoring Subject RIV: BH - Optics, Masers, Lasers

  16. Ultrasensitive laser spectroscopy for breath analysis

    Science.gov (United States)

    Wojtas, J.; Bielecki, Z.; Stacewicz, T.; Mikołajczyk, J.; Nowakowski, M.

    2012-03-01

    At present there are many reasons for seeking new methods and technologies that aim to develop new and more perfect sensors for different chemical compounds. However, the main reasons are safety ensuring and health care. In the paper, recent advances in the human breath analysis by the use of different techniques are presented. We have selected non-invasive ones ensuring detection of pathogenic changes at a molecular level. The presence of certain molecules in the human breath is used as an indicator of a specific disease. Thus, the analysis of the human breath is very useful for health monitoring. We have shown some examples of diseases' biomarkers and various methods capable of detecting them. Described methods have been divided into non-optical and optical methods. The former ones are the following: gas chromatography, flame ionization detection, mass spectrometry, ion mobility spectrometry, proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry. In recent twenty years, the optical methods have become more popular, especially the laser techniques. They have a great potential for detection and monitoring of the components in the gas phase. These methods are characterized by high sensitivity and good selectivity. The spectroscopic sensors provide the opportunity to detect specific gases and to measure their concentration either in a sampling place or a remote one. Multipass spectroscopy, cavity ring-down spectroscopy, and photo-acoustic spectroscopy were characterised in the paper as well.

  17. Robust Collimation Control of Laser-Generated Ion Beam

    OpenAIRE

    Kawata, S; Takano, M.; Kamiyama, D.; T. Nagashima; Barada, D.; Gu, Y. J.; Li, X; Yu, Q; Kong, Q.; Wang, P. X.

    2015-01-01

    The robustness of a structured collimation device is discussed for an intense-laser-produced ion beam. In this paper the ion beam collimation is realized by the solid structured collimation device, which produces the transverse electric field; the electric field contributes to reduce the ion beam transverse velocity and collimate the ion beam. Our 2.5 dimensional particle-in cell simulations demonstrate that the collimation device is rather robust against the changes in the laser parameters a...

  18. Radial smoothing for improving laser-beam irradiance uniformity.

    Science.gov (United States)

    Zhong, Zheqiang; Hou, Pengcheng; Zhang, Bin

    2015-12-15

    Laser-beam irradiation uniformity is a key issue in inertial confinement fusion research. We propose a radial smoothing (RS) approach in which the speckle in a focal plane is smoothed by the radial redistribution through fast focal zooming. This focal zooming is generated by introducing the periodical spherical wavefront modulation to the laser beam, based on an optical Kerr medium and its pump laser with the temporal profile of a Gaussian pulse train. The utilization of RS significantly improves the laser-beam uniformity without obvious impact on the performance of the high-power laser system. PMID:26670528

  19. Study on the Beam Quality of Uncoupled Laser Diode Arrays

    Institute of Scientific and Technical Information of China (English)

    GAO Chunqing; WEI Guanghui

    2001-01-01

    The beam quality of uncoupled laser diode array is studied theoretically and experimentally. By calculating the second order moments of the beam emitted from the laser diode array, the dependence of the M2-factor of the laser diode array on the M2-factor of the single emitter, the ratio of the emitting region to the non-emitting space, and the number of emitters, has been deduced. From the measurement of the beam propagation the M2-factor of a laser diode bar is experimentally determined. The measured M2-factor of the laser diode bar agrees with the theoretical prediction.

  20. Automatic tracking of laser and electron beam intersection

    International Nuclear Information System (INIS)

    For the Compton Polarimeter experiment at the Stanford Linear Accelerator the crossing point of a laser beam across the path of an electron beam must be kept accurate and stable. This paper describes an electronic system for automatic tracking and correction of the beam crossing. A remote CCD camera, relatively insensitive to electromagnetic disturbance, records small displacements of the pulsed laser beam. Video signals are analyzed at a remote station, the amount of drift from the selected reference point determined and the appropriate correction command sent to the motorized mirror deflecting the laser beam. A description of the system, its performance and the test results are presented

  1. Molecular-beam spectroscopy of interhalogen molecules

    International Nuclear Information System (INIS)

    A molecular-beam electric-resonance spectrometer employing a supersonic nozzle source has been used to obtain hyperfine spectra of 79Br35Cl. Analyses of these spectra and of microwave spectra published by other authors have yielded new values for the electric dipole moment and for the nuclear quadrupole coupling constants in this molecule. The new constants are significantly different from the currently accepted values. Van der Waals clusters containing chlorine monofluoride have been studied under various expansion conditions by the molecular-beam electric-deflection method. The structural possibilities indicated by the results are discussed, and cluster geometries are proposed

  2. Staging laser plasma accelerators for increased beam energy

    International Nuclear Information System (INIS)

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.

  3. Staging laser plasma accelerators for increased beam energy

    Energy Technology Data Exchange (ETDEWEB)

    Panasenko, Dmitriy; Shu, Anthony; Schroeder, Carl; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas; Cormier-Michel, Estelle; Plateau, Guillaume; Lin, Chen; Toth, Csaba; Geddes, Cameron; Esarey, Eric; Leemans, Wim

    2008-09-29

    Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.

  4. First on-line results from the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line at ISOLDE

    International Nuclear Information System (INIS)

    The CRIS (Collinear Resonant Ionisation Spectroscopy) experiment at the on-line isotope separator facility, ISOLDE, CERN, has been constructed for high-sensitivity laser spectroscopy measurements on radioactive isotopes. The technique determines the magnetic dipole and electric quadrupole moments, nuclear spin and changes in mean-square charge radii of exotic nuclei via measurement of their hyperfine structures and isotope shifts. In November 2011 the first on-line run was performed using the CRIS beam line, when the hyperfine structure of 207Fr was successfully measured. This paper will describe the technique and experimental setup of CRIS and present the results from the first on-line experiment.

  5. Laser Plasmas : Optical guiding of laser beam in nonuniform plasma

    Indian Academy of Sciences (India)

    Tarsem Singh Gill

    2000-11-01

    A plasma channel produced by a short ionising laser pulse is axially nonuniform resulting from the self-defocusing. Through such preformed plasma channel, when a delayed pulse propagates, the phenomena of diffraction, refraction and self-phase modulation come into play. We have solved the nonlinear parabolic partial differential equation governing the propagation characteristics for an approximate analytical solution using variational approach. Results are compared with the theoretical model of Liu and Tripathi (Phys. Plasmas 1, 3100 (1994)) based on paraxial ray approximation. Particular emphasis is on both beam width and longitudinal phase delay which are crucial to many applications.

  6. Measurement of Nuclear Moments and Radii by Collinear Laser Spectroscopy

    CERN Multimedia

    Geithner, W R; Lievens, P; Kotrotsios, G; Silverans, R; Kappertz, S

    2002-01-01

    %IS304 %title\\\\ \\\\Collinear laser spectroscopy on a fast beam has proven to be a widely applicable and very efficient tool for measurements of changes in mean square nuclear charge radii, nuclear spins, magnetic dipole and electric quadrupole moments. Recent developments of extremely sensitive non-optical detection schemes enabled for some elements the extension of the measurements towards the very short-lived isotopes in the far wings of the ISOLDE production curves. The gain in sensitivity opens up new perspectives, particularly for measurements on lighter nuclei whose ground-state properties can be interpreted by large scale microscopic calculations instead of the more phenomenologic models used for heavier nuclei.\\\\ \\\\ For the sequence of argon isotopes $^{32-40}$Ar and $^{46}$Ar isotope shifts and nuclear moments were measured by optical pumping followed by state selective collisional ionization and detection of the $\\beta$-decay. Similarly, the low-background $\\alpha$-detection was used to extend earlie...

  7. Double-pulse laser ablation coupled to laser-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Laser ablation coupled to laser-induced breakdown spectroscopy (LA-LIBS) is an analytical method, which minimizes sample matrix effects typically found in quantitative LIBS-based direct solid analyses. This paper reports the application of double-pulse laser ablation (DP-LA) to improve the analyte response and the achievable precisions of LA-LIBS. Two coaxial laser beams were applied at the ablation site and the analytical signals were then collected from a second free-standing LIBS plasma downstream of the ablation site. Signal improvements of up to one order of magnitude were observed compared to single-pulse LA-LIBS. The effect of the interpulse delay on the observed signal-to-noise ratios was studied and the quantification capabilities of the optimized DP-LA-LIBS setup were investigated for manganese and iron in a broad range of different alloy types. A linear response was observed for manganese across the different matrices, allowing for nonmatrix-matched calibrations. Matrix effects were observed when analyzing aluminum samples, which, however, could be compensated for by applying iron as internal standard. Size distributions of the ablated material and electron density measurements provide additional insight into the double-pulse process, with additional future work suggested. - Highlights: • Double-pulse laser ablation was coupled to laser-induced breakdown spectroscopy. • Nonmatrix-matched calibration of manganese in various alloys was performed. • Improved sensitivities and precisions compared to single-pulse LA were demonstrated. • Remaining matrix effects and internal standardization are discussed

  8. Scrape-off layer-induced beam density fluctuations and their effect on beam emission spectroscopy

    Science.gov (United States)

    Moulton, D.; Marandet, Y.; Tamain, P.; Dif-Pradalier, G.

    2015-07-01

    A statistical model is presented to calculate the magnitude of beam density fluctuations generated by a turbulent scrape-off layer (SOL). It is shown that the SOL can induce neutral beam density fluctuations of a similar magnitude to the plasma density fluctuations in the core, potentially corrupting beam emission spectroscopy measurements. The degree of corruption is quantified by combining simulations of beam and plasma density fluctuations inside a simulated measurement window. A change in pitch angle from the separatrix to the measurement window is found to reduce the effect of beam fluctuations, whose largest effect is to significantly reduce the measured correlation time.

  9. Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

    Directory of Open Access Journals (Sweden)

    Javis Anyangwe Nwaboh

    2011-01-01

    Full Text Available We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS, quantum cascade laser absorption spectroscopy (QCLAS, and cavity ring down spectroscopy (CRDS, all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

  10. Laboratory diode laser spectroscopy in molecular planetary astronomy

    Science.gov (United States)

    Jennings, D. E.

    1988-01-01

    Infrared spectroscopy of planetary atmospheres is performed at high spectral resolution comparable to that in the laboratory. This requires that laboratory spectroscopy use the highest resolution and the most accurate techniques. Tunable diode laser spectroscopy can supply many of the spectroscopic parameters needed by astronomers. In particular, line positions, line strengths, and collisional line widths are measured with diode lasers, and these are often among the best values available. Diode laser spectra are complimentary to lower resolution, broader-coverage Fourier transform spectra. Certain procedures must be adopted, however, when using diode lasers, for determining their output characteristics and for calibrating each spectrum against quality references.

  11. Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

    International Nuclear Information System (INIS)

    We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM) method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS), quantum cascade laser absorption spectroscopy (QCLAS), and cavity ring down spectroscopy (CRDS), all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

  12. Laser induced breakdown spectroscopy inside liquids: Processes and analytical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Lazic, V., E-mail: violeta.lazic@enea.it [ENEA (UTAPRAD-DIM), Via. E. Fermi 45, 00044 Frascati (RM) (Italy); Jovićević, S. [Institute of Physics, University of Belgrade, 11080 Belgrade (Serbia)

    2014-11-01

    This paper provides an overview of the laser induced breakdown spectroscopy (LIBS) inside liquids, applied for detection of the elements present in the media itself or in the submerged samples. The processes inherent to the laser induced plasma formation and evolution inside liquids are discussed, including shockwave generation, vapor cavitation, and ablation of solids. Types of the laser excitation considered here are single pulse, dual pulse and multi-pulse. The literature relative to the LIBS measurements and applications inside liquids is reviewed and the most relevant results are summarized. Finally, we discuss the analytical aspects and release some suggestions for improving the LIBS sensitivity and accuracy in liquid environment. - Highlights: • The paper reviews LIBS applications on bulk liquids and on submerged samples, using single, dual and multi pulse excitation. • The fundamentals about plasma in liquids are provided: beam transmission, breakdown, ablation, cavitation, and energy balance • Influence of the bubble’s optical properties on the plasma formation and detection after the second pulse is considered • The results obtained by various research groups and in different experimental conditions are reviewed and summarized • The analytical aspects are discussed, which include the experimental part, signal stability, data processing and calibration.

  13. Laser induced breakdown spectroscopy inside liquids: Processes and analytical aspects

    International Nuclear Information System (INIS)

    This paper provides an overview of the laser induced breakdown spectroscopy (LIBS) inside liquids, applied for detection of the elements present in the media itself or in the submerged samples. The processes inherent to the laser induced plasma formation and evolution inside liquids are discussed, including shockwave generation, vapor cavitation, and ablation of solids. Types of the laser excitation considered here are single pulse, dual pulse and multi-pulse. The literature relative to the LIBS measurements and applications inside liquids is reviewed and the most relevant results are summarized. Finally, we discuss the analytical aspects and release some suggestions for improving the LIBS sensitivity and accuracy in liquid environment. - Highlights: • The paper reviews LIBS applications on bulk liquids and on submerged samples, using single, dual and multi pulse excitation. • The fundamentals about plasma in liquids are provided: beam transmission, breakdown, ablation, cavitation, and energy balance • Influence of the bubble’s optical properties on the plasma formation and detection after the second pulse is considered • The results obtained by various research groups and in different experimental conditions are reviewed and summarized • The analytical aspects are discussed, which include the experimental part, signal stability, data processing and calibration

  14. Collinear laser spectroscopy of manganese isotopes using optical pumping in ISCOOL

    CERN Multimedia

    Marsh, B A; Neyens, G; Flanagan, K; Rajabali, M M; Reponen, M; Campbell, P; Procter, T J

    Recently, optical pumping of ions has been achieved inside an ion beam cooler-buncher. By illuminating the central axis of the cooler with laser light, subsequent decay populates selected ionic metastable states. This population enhancement is retained as the ion beam is delivered to an experimental station. In the case of collinear laser spectroscopy, transitions can then be excited from a preferred metastable level, rather than the ground-state. This proposal seeks to establish and develop the technique for ISCOOL. As a test of efficiency, this will be applied to the study of $^{55-66}$Mn isotopes using collinear laser spectroscopy-expanding an earlier study where the benefit of the technique was demonstrated. This will provide nuclear spins, magnetic-dipole and electric-quadrupole moments and changes in mean-square charge radii across N = 40 shell closure candidate and into a region where an onset of deformation, and a new "island of inversion" is predicted.

  15. Development of a Laser Wire Beam Profile Monitor, 1

    CERN Document Server

    Sakamura, Y; Matsuo, H; Sakai, H; Sasao, N; Higashi, Y; Korhonen, T T; Taniguchi, T; Urakawa, J; Sakamura, Yutaka; Hemmi, Yasuo; Matsuo, Hiroaki; Sakai, Hiroshi; Sasao, Noboru; Higashi, Yasuo; Korhonen, Timo; Taniguchi, Takashi; Urakawa, Junji

    1999-01-01

    A conceptual design work and a basic experimental study of a new beam profile monitor have been performed. The monitor will be used to measure emittance of an electron beam in the ATF damping ring at KEK, in which the transverse beam size of about 10 micron is expected. It utilizes a CW laser and an optical cavity, instead of a material wire, to minimize interference with an electron beam. A laser beam with a very thin waist is realized by employing the cavity of nearly concentric mirror configuration while the intensity is amplified by adjusting the cavity length to a Fabry-Perot resonance condition. We built a test cavity to establish a method to measure important parameters such as a laser beam waist and a power enhancement factor. Three independent methods were examined for the measurement of the beam waist. It was found that the cavity realized the beam waist of 20 micron with the power enhancement factor of 50.

  16. Laser cooling and ion beam diagnosis of relativistic ions in a storage ring

    International Nuclear Information System (INIS)

    Particle accelerator and storage ring technology has reached an advanced state, so that different heavy ion storage rings are coming into operation by now, capable of storing even fully stripped ions up to U92+. The main purpose of these machines are the accumulation of ions and the ability of improving the beam quality, that is the phase space density of the stored beams. This beam cooling is done successfully by the well established stochastic and electron cooling techniques. A new cooling method, the laser cooling, is taken over from atomic beam and ion trap experiments, where it has yielded extremely low temperatures of atomic samples. As a canditate at storage rings 7Li+ ions are stored in the Heidelberg TSR at 13.3 MeV. The ion beam properties of the metastable fraction like momentum spread, storage time and the influence of residual gas scattering are investigated by colinear laser spectroscopy in the experimental section of the TSR. An optical pumping experiment using two dye laser systems yields information about ion kinematics and velocity mixing processes in the ring. Lifetimes in the order of 100 ms for velocity classes marked in this way show that laser cooling can be applied to the stored 7Li+ beam. In an experimental situation of two strong counterpropagating laser beams, both tuned near resonance, a dramatic reduction of the ion beam momentum spread is observed. With a special geometrical control of laser and ion beam the longitudinal beam temperature is reduced from 260 K to at least 3 K with very high collection efficiency. (orig./HSI)

  17. In-beam γ-ray spectroscopy of fast beams at the NSCL

    International Nuclear Information System (INIS)

    With the development of an array of highly-segmented germanium detectors, it now becomes possible to perform in-flight γ-ray spectroscopy experiments on intermediate energy beams with unprecedented γ-ray energy resolution. Presented in this report are examples of two techniques in which SeGA, the most highly-segmented operational germanium array for in-flight spectroscopy with fast beams, was used for the detection of γ rays. SeGA used in conjunction with a high-resolution magnetic spectrograph (S800) to detect the reaction residues in coincidence represents a powerful combination for in-beam γ-ray studies

  18. Focusing of particle beams using two-stage laser ablation

    International Nuclear Information System (INIS)

    We report a new technique for producing focused beams of neutrals, ions, and clusters using two-stage laser ablation. We have produced a collimated beam and beams which were focused in one and two dimensions. The on-axis density is 5 x 1015 atoms/cm3 for a barium beam focused in two dimensions over a distance of 10.7 cm. For a collimated beam the density is 1015 atoms/cm3 at the same distance

  19. Beam deflection by planar–curved laser channels

    International Nuclear Information System (INIS)

    In this work based on channeling phenomenon the problem of electron beam deflection by plane averaged potential formed by two crossed lasers is described. The effective potential formed at grazing reflection of laser field from curved conducting surface is derived. The critical radius for electron steering in such a system as well as the conditions for effective beam reflection are introduced

  20. Beam deflection by planar–curved laser channels

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, E.N., E-mail: frol.onn@gmail.com [RAS P.N. Lebedev Physical Institute, Moscow (Russian Federation); NR Tomsk Polytechnic University, Tomsk (Russian Federation); Dik, A.V. [RAS P.N. Lebedev Physical Institute, Moscow (Russian Federation); Dabagov, S.B. [RAS P.N. Lebedev Physical Institute, Moscow (Russian Federation); NR Nuclear University MEPhI, Moscow (Russian Federation); INFN Laboratori Nazionali di Frascati, Frascati (Roma) (Italy)

    2015-07-15

    In this work based on channeling phenomenon the problem of electron beam deflection by plane averaged potential formed by two crossed lasers is described. The effective potential formed at grazing reflection of laser field from curved conducting surface is derived. The critical radius for electron steering in such a system as well as the conditions for effective beam reflection are introduced.

  1. Polarization Studies in Fast-Ion Beam Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2001-12-20

    In a historical review, the observations and the insight gained from polarization studies of fast ions interacting with solid targets are presented. These began with J. Macek's recognition of zero-field quantum beats in beam-foil spectroscopy as indicating alignment, and D.G. Ellis' density operator analysis that suggested the observability of orientation when using tilted foils. Lastly H. Winter's studies of the ion-beam surface interaction at grazing incidence yielded the means to produce a high degree of nuclear orientation in ion beams.

  2. Design of titania nanotube structures by focused laser beam direct writing

    Energy Technology Data Exchange (ETDEWEB)

    Enachi, Mihai [National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, MD-2004 (Moldova, Republic of); Stevens-Kalceff, Marion A. [School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Sarua, Andrei [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Ursaki, Veaceslav [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau, MD-2028 (Moldova, Republic of); Tiginyanu, Ion, E-mail: tiginyanu@asm.md [National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, MD-2004 (Moldova, Republic of); Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Chisinau, MD-2028 (Moldova, Republic of)

    2013-12-21

    In this work, we report on electrochemical fabrication of titania films consisting of nanotubes (NTs) and their treatment by focused laser beam. The results of sample characterization by optical and scanning electron microscopy, cathodoluminescence imaging, and Raman scattering scanning spectroscopy are compared to those inherent to specimens subjected to thermal treatment in a furnace. The obtained data demonstrate possibilities for controlling crystallographic structure of TiO{sub 2} NTs by focused laser beam direct writing. These findings open new prospects for the design and fabrication of spatial architectures based on titania nanotubes.

  3. Do twisted laser beams evoke nuclear hyperpolarization?

    Science.gov (United States)

    Schmidt, A B; Andrews, D L; Rohrbach, A; Gohn-Kreuz, C; Shatokhin, V N; Kiselev, V G; Hennig, J; von Elverfeldt, D; Hövener, J-B

    2016-07-01

    The hyperpolarization of nuclear spins promises great advances in chemical analysis and medical diagnosis by substantially increasing the sensitivity of nuclear magnetic resonance (NMR). Current methods to produce a hyperpolarized sample, however, are arduous, time-consuming or costly and require elaborate equipment. Recently, a much simpler approach was introduced that holds the potential, if harnessed appropriately, to revolutionize the production of hyperpolarized spins. It was reported that high levels of hyperpolarization in nuclear spins can be created by irradiation with a laser beam carrying orbital angular momentum (twisted light). Aside from these initial reports however, no further experimental verification has been presented. In addition, this effect has so far evaded a critical theoretical examination. In this contribution, we present the first independent attempt to reproduce the effect. We exposed a sample of immersion oil or a fluorocarbon liquid that was placed within a low-field NMR spectrometer to Laguerre-Gaussian and Bessel laser beams at a wavelength of 514.5nm and various topological charges. We acquired (1)H and (19)F NMR free induction decay data, either during or alternating with the irradiation that was parallel to B0. We observed an irregular increase in NMR signal in experiments where the sample was exposed to beams with higher values of the topological charge. However, at no time did the effect reach statistical significance of 95%. Given the measured sensitivity of our setup, we estimate that a possible effect did not exceed a hyperpolarization (at 5mT) of 0.14-6%, depending on the assumed hyperpolarized volume. It should be noted though, that there were some differences between our setup and the previous implementation of the experiment, which may have inhibited the full incidence of this effect. To approach a theoretical description of this effect, we considered the interaction of an electron with a plane wave, which is known to be

  4. Do twisted laser beams evoke nuclear hyperpolarization?

    Science.gov (United States)

    Schmidt, A. B.; Andrews, D. L.; Rohrbach, A.; Gohn-Kreuz, C.; Shatokhin, V. N.; Kiselev, V. G.; Hennig, J.; von Elverfeldt, D.; Hövener, J.-B.

    2016-07-01

    The hyperpolarization of nuclear spins promises great advances in chemical analysis and medical diagnosis by substantially increasing the sensitivity of nuclear magnetic resonance (NMR). Current methods to produce a hyperpolarized sample, however, are arduous, time-consuming or costly and require elaborate equipment. Recently, a much simpler approach was introduced that holds the potential, if harnessed appropriately, to revolutionize the production of hyperpolarized spins. It was reported that high levels of hyperpolarization in nuclear spins can be created by irradiation with a laser beam carrying orbital angular momentum (twisted light). Aside from these initial reports however, no further experimental verification has been presented. In addition, this effect has so far evaded a critical theoretical examination. In this contribution, we present the first independent attempt to reproduce the effect. We exposed a sample of immersion oil or a fluorocarbon liquid that was placed within a low-field NMR spectrometer to Laguerre-Gaussian and Bessel laser beams at a wavelength of 514.5 nm and various topological charges. We acquired 1H and 19F NMR free induction decay data, either during or alternating with the irradiation that was parallel to B0. We observed an irregular increase in NMR signal in experiments where the sample was exposed to beams with higher values of the topological charge. However, at no time did the effect reach statistical significance of 95%. Given the measured sensitivity of our setup, we estimate that a possible effect did not exceed a hyperpolarization (at 5 mT) of 0.14-6%, depending on the assumed hyperpolarized volume. It should be noted though, that there were some differences between our setup and the previous implementation of the experiment, which may have inhibited the full incidence of this effect. To approach a theoretical description of this effect, we considered the interaction of an electron with a plane wave, which is known to be

  5. Active steering of laser-accelerated ion beams

    International Nuclear Information System (INIS)

    A technique for optical control of the spatial distribution of laser-accelerated ion beams is presented. An ultrashort laser pulse, tightly focused to relativistic intensities on a thin foil target, drives a beam of MeV ions. An auxiliary, nanosecond laser pulse drives a shock and locally deforms the initially flat target prior to the main pulse interaction. By changing the properties of the shock-driving laser pulse, the normal direction of the ion emitting surface is locally manipulated and the emission direction is thereby controlled. In the future, this method could be used to achieve dynamic control of the ion beam divergence

  6. Laser tweezers Raman spectroscopy of single cells

    Science.gov (United States)

    Chen, De

    Raman scattering is an inelastic collision between the vibrating molecules inside the sample and the incident photons. During this process, energy exchange takes place between the photon and the scattering molecule. By measuring the energy change of the photon, the molecular vibration mode can be probed. The vibrational spectrum contains valuable information about the disposition of atomic nuclei and chemical bonds within a molecule, the chemical compositions and the interactions between the molecule and its surroundings. In this dissertation, laser tweezers Raman spectroscopy (LTRS) technique is applied for the analysis of biological cells and human cells at single cell level. In LTRS, an individual cell is trapped in aqueous medium with laser tweezers, and Raman scattering spectra from the trapped cell are recorded in real-time. The Raman spectra of these cells can be used to reveal the dynamical processes of cell growth, cell response to environment changes, and can be used as the finger print for the identification of a bacterial cell species. Several biophysical experiments were carried out using LTRS: (1) the dynamic germination process of individual spores of Bacillus thuringiensis was detected via Ca-DPA, a spore-specific biomarker molecule; (2) inactivation and killing of Bacillus subtilis spores by microwave irradiation and wet heat were studied at single cell level; (3) the heat shock activation process of single B. subtilis spores were analyzed, in which the reversible transition from glass-like state at low temperature to liquid-like state at high temperature in spore was revealed at the molecular level; (4) the kinetic processes of bacterial cell lysis of E. coli by lysozyme and by temperature induction of lambda phage were detected real-time; (5) the fixation and rehydration of human platelets were quantitatively evaluated and characterized with Raman spectroscopy method, which provided a rapid way to quantify the quality of freeze-dried therapeutic

  7. Mitigating the relativistic laser beam filamentation via an elliptical beam profile.

    Science.gov (United States)

    Huang, T W; Zhou, C T; Robinson, A P L; Qiao, B; Zhang, H; Wu, S Z; Zhuo, H B; Norreys, P A; He, X T

    2015-11-01

    It is shown that the filamentation instability of relativistically intense laser pulses in plasmas can be mitigated in the case where the laser beam has an elliptically distributed beam profile. A high-power elliptical Gaussian laser beam would break up into a regular filamentation pattern-in contrast to the randomly distributed filaments of a circularly distributed laser beam-and much more laser power would be concentrated in the central region. A highly elliptically distributed laser beam experiences anisotropic self-focusing and diffraction processes in the plasma channel ensuring that the unstable diffractive rings of the circular case cannot be produced. The azimuthal modulational instability is thereby suppressed. These findings are verified by three-dimensional particle-in-cell simulations. PMID:26651801

  8. Non-gated laser-induced breakdown spectroscopy in bulk water by position-selective detection

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Ye; Xue, Boyang; Song, Jiaojian; Lu, Yuan; Zheng, Ronger, E-mail: rzheng@ouc.edu.cn [Optics and Optoelectronics Laboratory, Ocean University of China, Qingdao 266100 (China)

    2015-09-14

    Temporal and spatial evolutions of the laser-induced plasma in bulk water are investigated using fast imaging and emission spectroscopic techniques. By tightly focusing a single-pulse nanosecond Nd: YAG laser beam into the bulk water, we generate a strongly expanded plasma with high reproducibility. Such a strong expanding plasma enables us to obtain well-resolved spectral lines by means of position-selective detection; hence, the time-gated detector becomes abdicable. The present results suggest not only a possible non-gated approach for underwater laser-induced breakdown spectroscopy but also give an insight into the plasma generation and expansion in bulk water.

  9. Doppler-free spectroscopy on tantalum atomic beam

    International Nuclear Information System (INIS)

    We demonstrate the usefulness of an atomic beam source for refractory metals in Doppler-free spectroscopy. The splittings between seven hyperfine components of the weak 578.01 nm transition in TaI are measured to +- 1 MHz. The hyperfine A and B coefficients for the upper and lower level are determined from the observed splittings. (orig.)

  10. High-power continuous-wave mid-infrared radiation generated by difference frequency mixing of diode-laser-seeded fiber amplifiers and its application to dual-beam spectroscopy

    Science.gov (United States)

    Lancaster, D. G.; Richter, D.; Curl, R. F.; Tittel, F. K.; Goldberg, L.; Koplow, J.

    1999-01-01

    We report the generation of up to 0.7 mW of narrow-linewidth (laser-seeded 0.6-W Er/Yb fiber amplifier in periodically poled LiNbO3. A conversion efficiency of 0.09%/W (0.47 mWW-2 cm-1) was achieved. A room-air CH4 spectrum acquired with a compact 80-m multipass cell and a dual-beam spectroscopic configuration indicates an absorption sensitivity of +/-2.8 x 10(-5) (+/-1 sigma), corresponding to a sub-parts-in-10(9) (ppb) CH4 sensitivity (0.8 ppb).

  11. Development of two-color laser system for high-resolution polarization spectroscopy measurements of atomic hydrogen.

    Science.gov (United States)

    Bhuiyan, A H; Satija, A; Naik, S V; Lucht, R P

    2012-09-01

    We have developed a high-spectral-resolution laser system for two-photon pump, polarization spectroscopy probe (TPP-PSP) measurements of atomic hydrogen in flames. In the TPP-PSP technique, a 243-nm laser beam excites the two-photon 1S-2S transition, and excited n=2 atoms are then detected by polarization spectroscopy of the n=2 to n=3 transition using 656-nm laser radiation. The single-frequency-mode 243 and 656-nm beams are produced using injection-seeded optical parametric generators coupled with pulsed dye amplifiers. The use of single-mode lasers allows accurate measurement of signal line shapes and intensities even with significant pulse-to-pulse fluctuations in pulse energies. Use of single-mode lasers and introduction of a scheme to select nearly constant laser energies enable repeatable extraction of important spectral features in atomic hydrogen transitions. PMID:22940950

  12. Laser cooling of electron beams at linear colliders

    OpenAIRE

    Telnov, Valery

    2000-01-01

    A method of electron beam cooling is considered which can be used for linear colliders. The electron beam is cooled during collision with focused powerful laser pulse. The ultimate transverse emittances are much below those achievable by other methods. This method is especially useful for high energy gamma-gamma colliders. In this paper we review and analyse limitations in this method, also discuss a new method of obtaining very high laser powers required for the laser cooling, radiation cond...

  13. Laser beam steering for GRACE Follow-On intersatellite interferometry

    OpenAIRE

    Schütze, D; Stede, G.; Müller, V.; Gerberding, O.; Bandikova, T.; Sheard, B.; Heinzel, G.; Danzmann, K

    2014-01-01

    The GRACE Follow-On satellites will use, for the first time, a Laser Ranging Interferometer to measure intersatellite distance changes from which fluctuations in Earth’s geoid can be inferred. We have investigated the beam steering method that is required to maintain the laser link between the satellites. Although developed for the specific needs of the GRACE Follow-On mission, the beam steering method could also be applied to other intersatellite laser ranging applications where major diffic...

  14. Gaussian Content as a Laser Beam Quality Parameter

    OpenAIRE

    Ruschin, Shlomo; Yaakobi, Elad; Shekel, Eyal

    2011-01-01

    We propose the Gaussian Content as an optional quality parameter for the characterization of laser beams. It is defined as the overlap integral of a given field with an optimally defined Gaussian. The definition is specially suited for applications where coherence properties are targeted. Mathematical definitions and basic calculation procedures are given along with results for basic beam profiles. The coherent combination of an array of laser beams and the optimal coupling between a diode la...

  15. High resolution imaging with TM01 laser beams

    Science.gov (United States)

    Dehez, Harold; Piché, Michel; De Koninck, Yves

    2009-06-01

    Using the vectorial diffraction theory established by Richards and Wolf, we demonstrate that the resolution of a two-photon microscope can be improved with a radially polarized TM01 laser beam and an interface between dielectrics, instead of the linearly polarized Gaussian beam already used in laser scanning microscopy. To verify the theoretical results, we developed a mode converter producing radially polarized beams and we have integrated it in a commercial two-photon microscope.

  16. Nematic Liquid Crystal Spatial Light Modulators for Laser Beam Steering

    OpenAIRE

    Hällstig, Emil

    2004-01-01

    Laser beam control is important in many applications. Phase modulating spatial light modulators (SLMs) can be used to electronically alter the phase distribution of an optical wave-front and thus change the direction and shape of a laser beam. Physical constraints set limitations to the SLM and an ideal phase distribution can usually not be realised. In order to understand how such components can be used for non-mechanical beam control three nematic liquid crystal (NLC) SLMs have been thoroug...

  17. In-beam spectroscopy of 231Pa

    International Nuclear Information System (INIS)

    Information on energy levels and on E2 and M1 matrix elements in 231Pa has been obtained using conversion-electron and gamma-ray spectroscopy following the 232Th(p, 2p)231Pa reaction and Coulomb excitation of the radioactive target 231Pa by 4He and 32S ions. The results are analyzed in the framework of the rotational model, applied to the rotational band built on the 1/2-[530] Nilsson state whose 3/2- member forms the ground state of this nucleus. The deviations of the level energies from the rigidrotor values can be described by Coriolis couplings. The analysis of the Coulomb-excitation process shows that a constant set of rotational parameters Q0, gR, gK, and b can fairly well account for the measured line intensities. (orig.)

  18. In-beam spectroscopy of 110Te

    International Nuclear Information System (INIS)

    The neutron-deficient nucleus 110Te has been investigated by in-beam spectroscopic methods using the NORDBALL multi-detector array. Except for the energy of one level observed in α-decay, excited states in 110Te were previously unknown. The level scheme constructed from γγ-coincidence relationships is presented with tentative spin assignments up to Iπ=21-. Above spin 8+ the yrast states have negative parity. They are most likely the members of a band predominantly based on the ν(h11/2g7/2) two-quasiparticle configuration. A band crossing is observed at Iπ ∼17-. It is suggested to be caused by the alignment of two h11/2 neutrons. The cranked shell model correctly predicts the spin alignment, but fails to reproduce the observed band crossing frequency, possibly because of octupole effects. ((orig.))

  19. Near-term feasibility demonstration of laser power beaming

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, H.W.

    1994-01-01

    A mission to recharge batteries of satellites in geostationary orbits (geosats) may be a commercially viable application which could be achieved with laser systems somewhat larger than present state-of-the-art. The lifetime of batteries on geosats is limited by repetitive discharge cycles which occur when the satellites are eclipsed by the earth during the spring and fall equinoxes. By coupling high power lasers with modern, large aperture telescopes and laser guide star adaptive optics systems, present day communications satellites could be targeted. It is important that a near term demonstration of laser power beaming be accomplished using lasers in the kilowatt range so that issues associated with high average power be addressed. The Laser Guide Star Facility at LLNL has all the necessary subsystems needed for such a near term demonstration, including high power lasers for both the power beam and guide star, beam directors and satellite tracking system.

  20. Hough Transform Based Corner Detection for Laser Beam Positioning

    International Nuclear Information System (INIS)

    In laser beam alignment in addition to detecting position, one must also determine the rotation of the beam. This is essential when a commissioning new laser beam for National Ignition Facility located at the Lawrence Livermore National Laboratory. When the beam is square, the positions of the corners with respect to one another provides an estimate of the rotation of the beam. This work demonstrates corner detection in the presence or absence of a second order non-uniform illumination caused by a spatial mask. The Hough transform coupled with illumination dependent pre-processing is used to determine the corner points. We show examples from simulated and real NIF images

  1. Hough Transform Based Corner Detection for Laser Beam Positioning

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, A S

    2005-07-26

    In laser beam alignment in addition to detecting position, one must also determine the rotation of the beam. This is essential when a commissioning new laser beam for National Ignition Facility located at the Lawrence Livermore National Laboratory. When the beam is square, the positions of the corners with respect to one another provides an estimate of the rotation of the beam. This work demonstrates corner detection in the presence or absence of a second order non-uniform illumination caused by a spatial mask. The Hough transform coupled with illumination dependent pre-processing is used to determine the corner points. We show examples from simulated and real NIF images.

  2. Laser Beam Caustic Measurement with Focal Spot Analyser

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Gong, Hui; Bagger, Claus

    2005-01-01

    In industrial applications of high power CO2-lasers the caustic characteristics of the laser beam have great effects on the performance of the lasers. A welldefined high intense focused spot is essential for reliable production results. This paper presents a focal spot analyser that is developed...

  3. Simulation of Laser-Compton Cooling of Electron Beams

    OpenAIRE

    Ohgaki, T.

    2000-01-01

    We study a method of laser-Compton cooling of electron beams. Using a Monte Carlo code, we evaluate the effects of the laser-electron interaction for transverse cooling. The optics with and without chromatic correction for the cooling are examined. The laser-Compton cooling for JLC/NLC at E_0=2 GeV is considered.

  4. Optical trapping with Bessel beams generated from semiconductor lasers

    International Nuclear Information System (INIS)

    In this paper, we study generation of Bessel beams from semiconductor lasers with high beam propagation parameter M2 and their utilization for optical trapping and manipulation of microscopic particles including living cells. The demonstrated optical tweezing with diodegenerated Bessel beams paves the way to replace their vibronic-generated counterparts for a range of applications towards novel lab-on-a-chip configurations

  5. Frequency modulation spectroscopy with a THz quantum-cascade laser

    OpenAIRE

    Eichholz, René; Richter, Heiko; Wienold, Martin; Schrottke, Lutz; Hey, R.; Grahn, H. T.; Hübers, H. -W.

    2013-01-01

    We report on a terahertz spectrometer for high-resolution molecular spectroscopy based on a quantum-cascade laser. High-frequency modulation (up to 50 MHz) of the laser driving current produces a simultaneous modulation of the frequency and amplitude of the laser output. The modulation generates sidebands, which are symmetrically positioned with respect to the laser carrier frequency. The molecular transition is probed by scanning the sidebands across it. In this way, the absorption and...

  6. The study of laser beam riding guided system based on 980nm diode laser

    Science.gov (United States)

    Qu, Zhou; Xu, Haifeng; Sui, Xin; Yang, Kun

    2015-10-01

    With the development of science and technology, precision-strike weapons has been considered to be important for winning victory in military field. Laser guidance is a major method to execute precision-strike in modern warfare. At present, the problems of primary stage of Laser guidance has been solved with endeavors of countries. Several technical aspects of laser-beam riding guided system have been mature, such as atmosphere penetration of laser beam, clutter inhibition on ground, laser irradiator, encoding and decoding of laser beam. Further, laser beam quality, equal output power and atmospheric transmission properties are qualified for warfare situation. Riding guidance instrument is a crucial element of Laser-beam riding guided system, and is also a vital element of airborne, vehicle-mounted and individual weapon. The optical system mainly consist of sighting module and laser-beam guided module. Photoelectric detector is the most important sensing device of seeker, and also the key to acquire the coordinate information of target space. Currently, in consideration of the 1.06 u m of wavelength applied in all the semi-active laser guided weapons systems, lithium drifting silicon photodiode which is sensitive to 1.06 u m of wavelength is used in photoelectric detector. Compared to Solid and gas laser, diode laser has many merits such as small volume, simple construction, light weight, long life, low lost and easy modulation. This article introduced the composition and operating principle of Laser-beam riding guided system based on 980 nm diode laser, and made a analysis of key technology; for instance, laser irradiator, modulating disk of component, laser zooming system. Through the use of laser diode, Laser-beam riding guided system is likely to have smaller shape and very light.

  7. Frequency stabilization of a 1083 nm fiber laser to 4He transition lines with optical heterodyne saturation spectroscopies

    International Nuclear Information System (INIS)

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable 4He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10−12@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry

  8. Chirped microlens arrays for diode laser circularization and beam expansion

    Science.gov (United States)

    Schreiber, Peter; Dannberg, Peter; Hoefer, Bernd; Beckert, Erik

    2005-08-01

    Single-mode diode lasers are well-established light sources for a huge number of applications but suffer from astigmatism, beam ellipticity and large manufacturing tolerances of beam parameters. To compensate for these shortcomings, various approaches like anamorphic prism pairs and cylindrical telescopes for circularization as well as variable beam expanders based on zoomed telescopes for precise adjustment of output beam parameters have been employed in the past. The presented new approach for both beam circularization and expansion is based on the use of microlens arrays with chirped focal length: Selection of lenslets of crossed cylindrical microlens arrays as part of an anamorphic telescope enables circularization, astigmatism correction and divergence tolerance compensation of diode lasers simultaneously. Another promising application of chirped spherical lens array telescopes is stepwise variable beam expansion for circular laser beams of fiber or solid-state lasers. In this article we describe design and manufacturing of beam shaping systems with chirped microlens arrays fabricated by polymer-on-glass replication of reflow lenses. A miniaturized diode laser module with beam circularization and astigmatism correction assembled on a structured ceramics motherboard and a modulated RGB laser-source for photofinishing applications equipped with both cylindrical and spherical chirped lens arrays demonstrate the feasibility of the proposed system design approach.

  9. Pengukuran Daya Laser CO2 Dan Laser DPSS Serta Pengamatan Beam Profiler Sinar Laser DPSS dan Laser He-Ne Menggunakan CCD

    OpenAIRE

    Manurung, Helen Martina

    2015-01-01

    This research has done measuring the power by varying the current of laser CO2 and laser DPSS, observation the beam profiler of laser beam DPSS and laser beam He-Ne and observation the spectrum wavelength of laser DPSS and laser He-Ne. In this case of measuring the power by varying the current of laser CO2 and laser DPSS, the measuring has done more than once in order to concluded how the stability of the power that produced by each of the laser. The result of this measuring is laser DPSS ...

  10. Helicopter engine exhaust rotor downwash effects on laser beams

    Science.gov (United States)

    Henriksson, Markus; Sjöqvist, Lars; Seiffer, Dirk

    2015-10-01

    The hot exhaust gases from engines on helicopters are pushed down by the rotor in a turbulent flow. When the optical path of a laser beam or optical sensor passes through this region severe aberrations of the optical field may result. These perturbations will lead to beam wander and beam distortions that can limit the performance of optical countermeasure systems. To quantify these effects the Italian Air Force Flight Test Centre hosted a trial for the "Airborne platform effects on lasers and warning sensors" (ALWS) EDA-project. Laser beams were propagated from the airport control tower to a target screen in a slant path with the helicopter hovering over this path. Collimated laser beams at 1.55-, 2- and 4.6-μm wavelength were imaged with high speed cameras. Large increases in beam wander and beam divergence were found, with beam wander up to 200 μrad root-mean-square and increases in beam divergence up to 1 mrad. To allow scaling to other laser beam parameters and geometries formulas for propagation in atmospheric turbulence were used even though the turbulence may not follow Kolmogorov statistics. By assuming that the plume is short compared to the total propagation distance the integrated structure parameter through the plume could be calculated. Values in the range 10-10 to 10-8 m1/3 were found when the laser beams passed through the exhaust gases below the helicopter tail. The integrated structure parameter values calculated from beam wander were consistently lower than those calculated from long term spot size, indicating that the method is not perfect but provides information about order of magnitudes. The measured results show that the engine exhaust for worst case beam directions will dominate over atmospheric turbulence even for kilometer path lengths from a helicopter at low altitude. How severe the effect is on system performance will depend on beam and target parameters.

  11. Research on applications of rectangular beam in micro laser propulsion

    International Nuclear Information System (INIS)

    Highlights: • Diode laser bar of 808 nm is introduced into the micro laser propulsion field. • Double base propellant (DBP) coating with BOPP substrate was obtained. • The combination of laser power and energy decides the propulsion performance. • The new rectangular beam prefers to produce higher impulse. - Abstract: Micro laser propulsion is a new technology with brilliant future. In order to reduce the thruster mass and volume further, laser bar is introduced into the micro laser propulsion field. A new kind of 220 × 20 μm rectangular beam of 808 nm was obtained by oval lens compressing the light of diode at fast axes and slow axes. The effect of laser power, energy and coating thickness of double base propellant on propulsion performance was studied. Propulsion performance of double base propellant under static and dynamic mode shows some different characters. Compared to round beam, the new beam prefers to produce higher impulse. Ablation efficiency of DBP shows better performance in short laser duration. The combination of power density and energy density decides the laser propulsion performance. The new rectangular beam is appropriate for millisecond micro-laser propulsion

  12. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Diaz, M; Ponce, L; Arronte, M; Flores, T [Laboratorio TecnologIa Laser, CICATA-IPN, Unidad Altamira, Carretera Tampico-Puerto Ind. Altamira, 89600, TAMPS (Mexico)

    2007-04-15

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained.

  13. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    International Nuclear Information System (INIS)

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained

  14. Emission spectroscopy analysis during Nopal cladodes dethorning by laser ablation

    Science.gov (United States)

    Peña-Díaz, M.; Ponce, L.; Arronte, M.; Flores, T.

    2007-04-01

    Optical emission spectroscopy of the pulsed laser ablation of spines and glochids from Opuntia (Nopal) cladodes was performed. Nopal cladodes were irradiated with Nd:YAG free-running laser pulses on their body, glochids and spines. Emission spectroscopy analyses in the 350-1000 nm region of the laser induced plasma were made. Plasma plume evolution characterization, theoretical calculations of plasma plume temperature and experiments varying the processing atmosphere showed that the process is dominated by a thermally activated combustion reaction which increases the dethorning process efficiency. Therefore, appropriate laser pulse energy for minimal damage of cladodes body and in the area beneath glochids and spines can be obtained.

  15. Laser beam steering for GRACE Follow-On intersatellite interferometry.

    Science.gov (United States)

    Schütze, Daniel; Stede, Gunnar; Müller, Vitali; Gerberding, Oliver; Bandikova, Tamara; Sheard, Benjamin S; Heinzel, Gerhard; Danzmann, Karsten

    2014-10-01

    The GRACE Follow-On satellites will use, for the first time, a Laser Ranging Interferometer to measure intersatellite distance changes from which fluctuations in Earth's geoid can be inferred. We have investigated the beam steering method that is required to maintain the laser link between the satellites. Although developed for the specific needs of the GRACE Follow-On mission, the beam steering method could also be applied to other intersatellite laser ranging applications where major difficulties are common: large spacecraft separation and large spacecraft attitude jitter. The beam steering method simultaneously coaligns local oscillator beam and transmitted beam with the laser beam received from the distant spacecraft using Differential Wavefront Sensing. We demonstrate the operation of the beam steering method on breadboard level using GRACE satellite attitude jitter data to command a hexapod, a six-degree-of-freedom rotation and translation stage. We verify coalignment of local oscillator beam/ transmitted beam and received beam of better than 10 μrad with a stability of 10 μrad/ √Hz in the GRACE Follow-On measurement band of 0.002...0.1 Hz. Additionally, important characteristics of the beam steering setup such as Differential Wavefront Sensing signals, heterodyne efficiency, and suppression of rotation-to-pathlength coupling are investigated and compared with analysis results. PMID:25321987

  16. Multi-beam Laser Doppler Vibrometer with fiber sensing head

    Science.gov (United States)

    Phua, P. B.; Fu, Y.; Guo, M.; Liu, H.

    2012-06-01

    Laser Doppler vibrometry (LDV) is a well known technique to measure the motions, vibrations and mode shapes of structures and machine components. Photodetector-based LDV can only offer a point-wise measurement. However, it is possible to scan the laser beam to build up a vibrometric image. These scanning laser Doppler vibrometers (SLDV) assume that the measurement conditions remain invariant while multiple and identical, sequential measurements are performed. This assumption makes SLDVs impractical to do measurement on transient events. In this paper, we introduce a new method of generating multiple laser beams with different frequency shifts. The laser beams are projected on different points, and the reflected beams interfere with a common reference beam. The cross-talk among object beams can be bypassed with a proper selection of frequency shifts. A simultaneous vibration measurement on multiple points is realized using a single photodetector. Based on the proposed spatial-encoding technology, a self-synchronized prototype of fiber-based multipoint laser Doppler vibrometer at 1550nm wavelength is developed. An addition red pilot laser is used for aiming purpose. It has the flexibility to measure the vibration of different points on various surfaces. The prototype is used to measure the vibration of different points on a cantilever beam and a plate. The measured results match well with simulation results using finite element method (FEM).

  17. Cross-Beam Energy Transfer Driven by Incoherent Laser Beams with Frequency Detuning

    Science.gov (United States)

    Maximov, A.; Myatt, J. F.; Short, R. W.; Igumenshchev, I. V.; Seka, W.

    2015-11-01

    In the direct-drive method of the inertial confinement fusion (ICF), the coupling of laser energy to target plasmas is strongly influenced by the effect of cross-beam energy transfer (CBET) between multiple driving laser beams. The laser -plasma interaction (LPI) model of CBET is based on the nonparaxial laser light propagation coupled with the low-frequency ion-acoustic-domain plasma response. Common ion waves driven by multiple laser beams play a very important role in CBET. The effect of the frequency detuning (colors) in the driving laser beams is studied and it is shown to significantly reduce the level of common ion waves and therefore the level of CBET. The differences between the LPI-based CBET model and the ray-based CBET model used in hydrocodes are discussed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  18. Atmospheric Error Correction of the Laser Beam Ranging

    OpenAIRE

    Saydi, J.; Lotfalian, A.; Abedi, M.; Khalilzadeh, J.; Saghafifar, H.

    2014-01-01

    Atmospheric models based on surface measurements of pressure, temperature, and relative humidity have been used to increase the laser ranging accuracy by ray tracing. Atmospheric refraction can cause significant errors in laser ranging systems. Through the present research, the atmospheric effects on the laser beam were investigated by using the principles of laser ranging. Atmospheric correction was calculated for 0.532, 1.3, and 10.6 micron wavelengths through the weather conditions of Tehr...

  19. Collinear laser spectroscopy of atomic cadmium

    CERN Document Server

    Frömmgen, Nadja; Bissell, Mark L; Bieroń, Jacek; Blaum, Klaus; Cheal, Bradley; Flanagan, Kieran; Fritzsche, Stephan; Geppert, Christopher; Hammen, Michael; Kowalska, Magdalena; Kreim, Kim; Krieger, Andreas; Neugart, Rainer; Neyens, Gerda; Rajabali, Mustafa M; Nörtershäuser, Wilfried; Papuga, Jasna; Yordanov, Deyan T

    2015-01-01

    Hyperfine structure $A$ and $B$ factors of the atomic $5s\\,5p\\,\\; ^3\\rm{P}_2 \\rightarrow 5s\\,6s\\,\\; ^3\\rm{S}_1$ transition are determined from collinear laser spectroscopy data of $^{107-123}$Cd and $^{111m-123m}$Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with $s_{1/2}$ and $d_{5/2}$ nuclear ground states and isomeric $h_{11/2}$ states is evaluated and a linear relationship is observed for all nuclear states except $s_{1/2}$. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic $5s\\,5p\\,\\; ^3\\mathrm{P}_2$ level is derived from multi-configuration Dirac-Hartree-Fock calculatio...

  20. Medical Applications of Laser Induced Breakdown Spectroscopy

    International Nuclear Information System (INIS)

    Sedentary lifestyle of human beings has resulted in various diseases and in turn we require a potential tool that can be used to address various issues related to human health. Laser Induced Breakdown Spectroscopy (LIBS) is one such potential optical analytical tool that has become quite popular because of its distinctive features that include applicability to any type/phase of samples with almost no sample preparation. Several reports are available that discusses the capabilities of LIBS, suitable for various applications in different branches of science which cannot be addressed by traditional analytical methods but only few reports are available for the medical applications of LIBS. In the present work, LIBS has been implemented to understand the role of various elements in the formation of gallstones (formed under the empyema and mucocele state of gallbladder) samples along with patient history that were collected from Purvancal region of Uttar Pradesh, India. The occurrence statistics of gallstones under the present study reveal higher occurrence of gallstones in female patients. The gallstone occurrence was found more prevalent for those male patients who were having the habit of either tobacco chewing, smoking or drinking alcohols. This work further reports in-situ LIBS study of deciduous tooth and in-vivo LIBS study of human nail

  1. Medical Applications of Laser Induced Breakdown Spectroscopy

    Science.gov (United States)

    Pathak, A. K.; Rai, N. K.; Singh, Ankita; Rai, A. K.; Rai, Pradeep K.; Rai, Pramod K.

    2014-11-01

    Sedentary lifestyle of human beings has resulted in various diseases and in turn we require a potential tool that can be used to address various issues related to human health. Laser Induced Breakdown Spectroscopy (LIBS) is one such potential optical analytical tool that has become quite popular because of its distinctive features that include applicability to any type/phase of samples with almost no sample preparation. Several reports are available that discusses the capabilities of LIBS, suitable for various applications in different branches of science which cannot be addressed by traditional analytical methods but only few reports are available for the medical applications of LIBS. In the present work, LIBS has been implemented to understand the role of various elements in the formation of gallstones (formed under the empyema and mucocele state of gallbladder) samples along with patient history that were collected from Purvancal region of Uttar Pradesh, India. The occurrence statistics of gallstones under the present study reveal higher occurrence of gallstones in female patients. The gallstone occurrence was found more prevalent for those male patients who were having the habit of either tobacco chewing, smoking or drinking alcohols. This work further reports in-situ LIBS study of deciduous tooth and in-vivo LIBS study of human nail.

  2. Cold Antihydrogen for Precise Laser Spectroscopy

    CERN Multimedia

    Bachor, P T; Gabrielse, G S; Walz, J; Hessels, E A; Tan, J; Oelert, W; George, M C; Grzonka, D J; Kossick, M; Storry, C H; Sefzick, T

    2002-01-01

    %AD-2 %title\\\\ \\\\The Antihydrogen TRAP Collaboration (ATRAP) seeks to do precise laser spectroscopy of antihydrogen. Comparisons of antihydrogen and hydrogen atoms should provide the most stringent test of CPT invariance involving baryons and leptons. ATRAP is an expansion of the TRAP collaboration that developed the techniques to take CERN antiprotons from an energy of 6 MeV (momentum 100 MeV/c) all the way down to thermal equilibrium at 4 K for storage. This storage energy is lower than realized previously by more than ten orders of magnitude. The TRAP techniques include slowing, capturing, electron cooling and stacking of antiprotons. ATRAP and other collaborations will use antiprotons from the Antiproton Decelerator (AD). This new facility makes sense for such experiments because we showed that antiprotons can be accumulated in a trap at much lower expense than was required in the earlier CERN AC-AA-LEAR complex. In the closest approach yet to the production of cold antihydrogen, collaboration members wer...

  3. An analytical model for finite radius dual-beam mode-mismatched thermal lens spectroscopy

    Science.gov (United States)

    Sabaeian, Mohammad; Nadgaran, Hamid

    2013-10-01

    In this work, a new model for dual-beam mode-mismatch thermal lens spectroscopy is presented. The model was based on a new analytical solution of time-dependent heat equation for finite radius cylindrical samples exposed to TEM00 excitation laser beams. The Fresnel diffraction integration method was used to calculate time-dependent on-axis probe beam intensity. All aberrations in thermal lens were taken into account. The model yields accurate values for absorption coefficient and thermal diffusivity of methylene blue aqueous solution. Furthermore, the optimized mode-mismatched version of this model when applied to pure water as a very low absorbent yields its absorption coefficient and thermal diffusivity values close to literature data. In contrast to traditional model, this model does not need to omit any term in its theory to fit the experimental data.

  4. Detection of vibrational-overtone excitation in water via laser-induced grating spectroscopy

    International Nuclear Information System (INIS)

    In this paper we describe a method, based on the laser-induced grating technique, for studying the spectroscopy of vibrational overtone-excited gas-phase water. Two phase-coherent visible laser beams whose frequencies are in the range of the third overtone of the OH stretch in water are crossed in the gas-phase sample. As the wavelength of these excitation beams is scanned through individual rovibrational OH overtone transitions, vibrational energy is deposited into the water in a spatially sinusoidal pattern. A fixed-frequency 266 nm probe laser beam is diffracted from the resultant transmission diffraction grating in water. We show that under collision-free conditions, probe laser diffraction is observed from the initially excited grating, which is a necessary condition for using this technique to study the absorption spectroscopy of the vibrationally excited molecules. Under multiple collision conditions, a probe laser wavelength-independent refractive index grating is formed within the bulk sample. In addition, we observe temporal oscillations in the grating diffraction efficiency arising from excitation of standing acoustic waves

  5. Laser beam deflection by flow and nonlinear self-focusing

    International Nuclear Information System (INIS)

    In general, it is found that the plasma density response to a laser beam close-quote s ponderomotive force is shifted in the direction of a transverse flow, which in turn deflects the laser beam in that direction, and retards the flow at a temporal rate which is proportional to the beam close-quote s spatial deflection rate. This rate is a rapidly increasing function of left-angle I right-angle, the average laser intensity. This may result in finite beam deflections after propagation over a distance of a few speckle lengths for random phase plate optics. In current gas filled hohlraum experiments, the estimated magnitude of these effects is consistent with their experimental observation and one may need to include this physics in order to predict beam pointing which results in a symmetric capsule implosion. Flow retardation may be sufficient to exclude flow from the beam, self-limiting the deflection process. copyright 1996 American Institute of Physics

  6. Molecular spectroscopy with a multimode THz quantum-cascade laser

    OpenAIRE

    Eichholz, Rene; Richter, Heiko; Pavlov, Sergey; Semenov, A. D.; Wienold, M; Schrottke, L; Giehler, M.; Hey, R.; Grahn, H. T.; Hübers, Heinz-Wilhelm

    2011-01-01

    A terahertz absorption spectrometer for highresolution molecular spectroscopy is realized. The spectrometer is based on a multimode quantum-cascade laser. The design and performance of the spectrometer are presented. Three aspects are discussed: sensitivity, frequency calibration, and frequency multiplexing.

  7. Compact High Sensitive Laser-Induced Breakdown Spectroscopy Instrument Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Laser induced breakdown spectroscopy (LIBS) is a versatile tool for in situ substance characterization. Existing LIBS instruments are not compact enough for space...

  8. Genomic Physics. Multiple Laser Beam Treatment of Alzheimer's Disease

    Science.gov (United States)

    Stefan, V. Alexander

    2014-03-01

    The synapses affected by Alzheimer's disease can be rejuvenated by the multiple ultrashort wavelength laser beams.[2] The guiding lasers scan the whole area to detect the amyloid plaques based on the laser scattering technique. The scanning lasers pinpoint the areas with plaques and eliminate them. Laser interaction is highly efficient, because of the focusing capabilities and possibility for the identification of the damaging proteins by matching the protein oscillation eigen-frequency with laser frequency.[3] Supported by Nikola Tesla Labs, La Jolla, California, USA.

  9. Compact two-beam push-pull free electron laser

    Science.gov (United States)

    Hutton, Andrew

    2009-03-03

    An ultra-compact free electron laser comprising a pair of opposed superconducting cavities that produce identical electron beams moving in opposite directions such that each set of superconducting cavities accelerates one electron beam and decelerates the other electron beam. Such an arrangement, allows the energy used to accelerate one beam to be recovered and used again to accelerate the second beam, thus, each electron beam is decelerated by a different structure than that which accelerated it so that energy exchange rather than recovery is achieved resulting in a more compact and highly efficient apparatus.

  10. Frequency stabilization of a 399-nm laser by modulation transfer spectroscopy in an ytterbium hollow cathode lamp

    International Nuclear Information System (INIS)

    The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on various parameters. Under the optimum condition, the laser frequency at 399 nm can be stabilized. The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser. The laser frequency is shown to be tightly locked, and the stabilized laser is successfully applied to the cooling of ytterbium atoms. (atomic and molecular physics)

  11. Modifications of the laser beam coherence inertial confinement fusion plasmas

    International Nuclear Information System (INIS)

    Inertial confinement fusion by laser requires smoothed laser beam with well-controlled coherence properties. Such beams are made of many randomly distributed intensity maxima: the so-called speckles. As the laser beam propagates through plasma its temporal and spatial coherence can be reduced. This phenomenon is called plasma induced smoothing. For high laser intensities, instabilities developing independently inside the speckles are responsible for the coherence loss. At lower intensities, only collective effects, involving many speckles, can lead to induced smoothing. This thesis is a theoretical, numerical and experimental study of these mechanisms. Accounting for the partially incoherent behavior of the laser beams requires the use of statistical description of the laser-plasma interaction. A model is developed for the multiple scattering of the laser light on the self-induced density perturbations that is responsible for a spreading of the temporal and spatial spectra of the transmitted light. It also serves as a strong seed for the instability of forward stimulated Brillouin scattering that induces both, angular spreading and red-shift of the transmitted light. A statistical model is developed for this instability. A criterion is obtained that gives a laser power (below the critical power for filamentation) above which the instability growth is important. Numerical simulations with the interaction code PARAX and an experiment performed on the ALISE laser facility confirm the importance of these forward scattering mechanisms in the modification of the laser coherence properties. (author)

  12. Laser spectroscopy of gas confined in nanoporous materials

    CERN Document Server

    Svensson, Tomas

    2009-01-01

    We show that high-resolution laser spectroscopy can probe surface interactions of gas confined in nano-cavities of porous materials. We report on strong line broadening and unfamiliar lineshapes due to tight confinement, as well as signal enhancement due to multiple photon scattering. This new domain of laser spectroscopy constitute a challenge for the theory of collisions and spectroscopic lineshapes, and open for new ways of analyzing porous materials and processes taking place therein.

  13. Laser beam combiner for Thomson scattering core LIDAR

    Energy Technology Data Exchange (ETDEWEB)

    Balboa, I.; Naylor, G.; Sirinelli, A.; Parsons, P.; Fessey, J.; Townsend, M.; Beurskens, M.; Conway, N.; Kempenaars, M.; Kirk, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Huang, B. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Walsh, M. [Diagnostics Division, Department of CHD, ITER Organization, CS 90 046, Bulding 155/55, Route de Vinon, 13607 Saint-Paul-Lez-Durance Cedex (France); Flanagan, J.

    2010-10-15

    The light detection and ranging Thomson scattering (TS) diagnostic is advantageous since it only requires a single view port into the tokamak. This technique requires a short pulse laser at high energy, usually showing a limited repetition rate. Having multiple lasers will increase the repetition rate. This paper presents a scanning mirror as a laser beam combiner. Measurements of the position accuracy and jitter show that the pointing stability of the laser beam is within {+-}25 {mu}rad for over tens of seconds. A control feedback loop is implemented to demonstrate the long term stability. Such a system could be applied for ITER and JET.

  14. Beam profile shaping for laser radars that use detector arrays.

    Science.gov (United States)

    Veldkamp, W B; Kastner, C J

    1982-01-15

    The beam shaper we developed shapes the transmit beam of a CO(2) laser radar that uses a linear detector array. It consists of a diffraction grating and an anamorphic prism beam compressor and produces a stretched profile that efficiently and uniformly illuminates the far-field footprint of the detector array. The diffraction grating phase modulates the near field or the laser beam to generate a far-field flattop intensity profile, whereas the compressor produces the necessary profile eccentricity. We have achieved conversion efficiencies in the 70-90% range. PMID:20372453

  15. Collinear laser spectroscopy on radioactive praseodymium ions and cadmium ions

    International Nuclear Information System (INIS)

    Collinear laser spectroscopy is a tool for the model independent determination of spins, charge radii and electromagnetic moments of nuclei in ground and long-lived isomeric states. In the context of this thesis a new offline ion source for high evaporating temperatures and an ion beam analysis system were implemented at the TRIGA-LASER Experiment at the Institute for Nuclear Chemistry at the University of Mainz. The main part of the thesis deals with the determination of the properties of radioactive praseodymium and cadmium isotopes by collinear laser spectroscopy at ISOLDE/CERN. The necessary test measurements for the spectroscopy of praseodymium ions have been conducted with the aforementioned offline ion source at the TRIGA-LASER experiment. The spectroscopy of the praseodymium ions was motivated by the observation of a modulation of the electron capture decay rates of hydrogen-like 140Pr58+. The nuclear magnetic moment of the nucleus is, among others, required for the explanation of the so-called GSI Oscillations and has not been studied experimentally before. Additionally, the determined electron capture decay constant of hydrogen-like 140Pr58+ is lower than the one of helium-like 140Pr57+. The explanation of this phenomenon requires a positive magnetic moment. During the experiment at the COLLAPS apparatus the magnetic moments of the neutron-deficient isotopes 135Pr, 136Pr and 137Pr could be determined for the first time. Unfortunately, due to a too low production yield the desired isotope 140Pr could not be studied.The systematic study of cadmium isotopes was motivated by nuclear physics in the tin region. With Z=48 two protons are missing for the shell closure and the isotopes extend from the magic neutron number N=50 to the magic neutron number N=82. The extracted nuclear properties allow tests of different nuclear models in this region. In this thesis the obtained results of the spectroscopy of the cadmium isotopes 106-124,126Cd and their long-lived I

  16. Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

    Science.gov (United States)

    Scisciò, M.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Papaphilippou, Y.; Antici, P.

    2016-03-01

    In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupoles and solenoids) as an easy implementable solution when the laser-plasma accelerated beam requires optimization. In this paper, we report on a parametric study related to the transport of electron beams accelerated by laser-plasma interaction, using conventional accelerator elements and tools. We focus on both, high energy electron beams in the GeV range, as produced on petawatt (PW) class laser systems, and on lower energy electron beams in the hundreds of MeV range, as nowadays routinely obtained on commercially available multi-hundred TW laser systems. For both scenarios, our study allows understanding what are the crucial parameters that enable laser-plasma accelerators to compete with conventional ones and allow for a beam transport. We show that suitable working points require a tradeoff-combination between low beam divergence and narrow energy spread.

  17. Activation of cells using femtosecond laser beam (Conference Presentation)

    Science.gov (United States)

    Batabyal, Subrata; Satpathy, Sarmishtha; Kim, Young-tae; Mohanty, Samarendra K.

    2016-03-01

    Study of communication in cellular systems requires precise activation of targeted cell(s) in the network. In contrast to chemical, electrical, thermal, mechanical stimulation, optical stimulation is non-invasive and is better suited for stimulation of targeted cells. As compared to visible lasers, the near infrared (NIR) microsecond/nanosecond pulsed laser beams are being used as preferred stimulation tool as they provide higher penetration depth in tissues. Femotosecond (FS) laser beams in NIR are also being used for direct and indirect (i.e. via two-photon optogenetics) stimulation of cells. Here, we present a comparative evaluation of efficacy of NIR FS laser beam for direct (no optogenetic sensitization) and 2ph optogenetic stimulation of cells. Further, for the first time, we demonstrate the use of blue (~450 nm, obtained by second harmonic generation) FS laser beam for stimulation of cells with and without Channelrhodopisn-2 (ChR2) expression. Comparative analysis of photocurrent generated by blue FS laser beam and continuous wave blue light for optogenetics stimulation of ChR2 transfected HEK cells will be presented. The use of ultrafast laser micro-beam for focal, non-contact, and repeated stimulation of single cells in a cellular circuitry allowed us to study the communication between different cell types.

  18. High energy gain electron beam acceleration by 100TW laser

    International Nuclear Information System (INIS)

    A laser wakefield acceleration experiment using a 100TW laser is planed at JAERI-Kansai. High quality and short pulse electron beams are necessary to accelerate the electron beam by the laser. Electron beam - laser synchronization is also necessary. A microtron with a photocathode rf-gun was prepared as a high quality electron injector. The quantum efficiency (QE) of the photocathode of 2x10-5 was obtained. A charge of 100pC from the microtron was measured. The emittance and pulse width of the electron beam was 6π mm-mrad and 10ps, respectively. In order to produce a short pulse electron beam, and to synchronize between the electron beam and the laser pulse, an inverse free electron laser (IFEL) is planned. One of problems of LWFA is the short acceleration length. In order to overcome the problem, a Z-pinch plasma waveguide will be prepared as a laser wakefield acceleration tube for 1 GeV acceleration. (author)

  19. Intense ion beams accelerated by ultra-intense laser pulses

    Science.gov (United States)

    Roth, Markus; Cowan, T. E.; Gauthier, J. C.; Vehn, J. Meyer-Ter; Allen, M.; Audebert, P.; Blazevic, A.; Fuchs, J.; Geissel, M.; Hegelich, M.; Karsch, S.; Pukhov, A.; Schlegel, T.

    2002-04-01

    The discovery of intense ion beams off solid targets irradiated by ultra-intense laser pulses has become the subject of extensive international interest. These highly collimated, energetic beams of protons and heavy ions are strongly depending on the laser parameters as well as on the properties of the irradiated targets. Therefore we have studied the influence of the target conditions on laser-accelerated ion beams generated by multi-terawatt lasers. The experiments were performed using the 100 TW laser facility at Laboratoire pour l'Utilisation des Laser Intense (LULI). The targets were irradiated by pulses up to 5×1019 W/cm2 (~300 fs,λ=1.05 μm) at normal incidence. A strong dependence on the surface conditions, conductivity, shape and purity was observed. The plasma density on the front and rear surface was determined by laser interferometry. We characterized the ion beam by means of magnetic spectrometers, radiochromic film, nuclear activation and Thompson parabolas. The strong dependence of the ion beam acceleration on the conditions on the target back surface was confirmed in agreement with predictions based on the target normal sheath acceleration (TNSA) mechanism. Finally shaping of the ion beam has been demonstrated by the appropriate tailoring of the target. .

  20. Diffractive beam shaping for enhanced laser polymer welding

    Science.gov (United States)

    Rauschenberger, J.; Vogler, D.; Raab, C.; Gubler, U.

    2015-03-01

    Laser welding of polymers increasingly finds application in a large number of industries such as medical technology, automotive, consumer electronics, textiles or packaging. More and more, it replaces other welding technologies for polymers, e. g. hot-plate, vibration or ultrasonic welding. At the same rate, demands on the quality of the weld, the flexibility of the production system and on processing speed have increased. Traditionally, diode lasers were employed for plastic welding with flat-top beam profiles. With the advent of fiber lasers with excellent beam quality, the possibility to modify and optimize the beam profile by beam-shaping elements has opened. Diffractive optical elements (DOE) can play a crucial role in optimizing the laser intensity profile towards the optimal M-shape beam for enhanced weld seam quality. We present results on significantly improved weld seam width constancy and enlarged process windows compared to Gaussian or flat-top beam profiles. Configurations in which the laser beam diameter and shape can be adapted and optimized without changing or aligning the laser, fiber-optic cable or optical head are shown.

  1. DPSS Laser Beam Quality Optimization Through Pump Current Tuning

    Energy Technology Data Exchange (ETDEWEB)

    Omohundro, Rob; /Newport Spectra-Physics, Santa Clara; Callen, Alice; /SLAC; Sukuta, Sydney; /San Jose City Coll.

    2012-03-30

    The goal of this study is to demonstrate how a DPSS laser beam's quality parameters can be simultaneously optimized through pump current tuning. Two DPSS lasers of the same make and model were used where the laser diode pump current was first varied to ascertain the lowest RMS noise region. The lowest noise was found to be 0.13% in this region and the best M{sup 2} value of 1.0 and highest laser output power were simultaneously attained at the same current point. The laser manufacturer reported a M{sup 2} value of 1.3 and RMS noise value of .14% for these lasers. This study therefore demonstrates that pump current tuning a DPSS laser can simultaneously optimize RMS Noise, Power and M{sup 2} values. Future studies will strive to broaden the scope of the beam quality parameters impacted by current tuning.

  2. Relativistic Electron Vortex Beams in a Laser Field.

    Science.gov (United States)

    Bandyopadhyay, Pratul; Basu, Banasri; Chowdhury, Debashree

    2015-11-01

    The orbital angular momentum Hall effect and the spin Hall effect of electron vortex beams (EVBs) have been studied for the EVBs interacting with a laser field. In the scenario of a paraxial beam, the cumulative effect of the orbit-orbit interaction of EVBs and laser fields drives the orbital Hall effect, which in turn produces a shift of the center of the beam from that of the field-free case towards the polarization axis of the photons. In addition, for nonparaxial beams one can also perceive a similar shift of the center of the beam owing to the spin Hall effect involving spin-orbit interaction. Our analysis suggests that the shift in the paraxial beams will always be larger than that in the nonparaxial beams. PMID:26588389

  3. Improving the selectivity of the ISOLDE resonance ionization laser ion source and in-source laser spectroscopy of polonium

    International Nuclear Information System (INIS)

    Exotic atomic nuclei far away from stability are fascinating objects to be studied in many scientific fields such as atomic-, nuclear-, and astrophysics. Since these are often short-lived isotopes, it is necessary to couple their production with immediate extraction and delivery to an experiment. This is the purpose of the on-line isotope separator facility, ISOLDE, at CERN. An essential aspect of this laboratory is the Resonance Ionization Laser Ion Source (RILIS) because it provides a fast and highly selective means of ionizing the reaction products. This technique is also a sensitive laser-spectroscopy tool for the development and improvement of electron excitation schemes for the resonant laser photoionization and the study of the nuclear structure or fundamental atomic physics. Each of these aspects of the RILIS applications are subjects of this thesis work: a new device for the suppression of unwanted surface ionized contaminants in RILIS ion beams, known as the Laser Ion Source and Trap (LIST), was implemented into the ISOLDE framework, further developed and characterized; a new electron-excitation scheme for the laser ionization of calcium was developed; the ionization energy of polonium was determined by high-precision Rydberg spectroscopy; and finally, the first ever on-line physics operation of the highly selective LIST enabled the study of nuclear structure properties of 217Po by in-source resonance ionization spectroscopy.

  4. Beam line design for synchrotron spectroscopy in the VUV

    International Nuclear Information System (INIS)

    The character of the radiation source provided by an electron storage ring is briefly reviewed from the point of view of utilization for VUV spectroscopy. The design of beam line components is then considered with special reference to the problems of contamination of optical surfaces and vacuum protection. The issues involved in designing mirrors for use with storage rings are considered with emphasis on the questions of power dissipation, image quality and materials selection

  5. Proceeding of the workshop on gamma-ray spectroscopy utilizing heavy-ion, photon and RI beams

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Sugita, Michiaki; Hayakawa, Takehito [eds.

    1998-03-01

    Three time since 1992, we have held the symposia entitled `Joint Spectroscopy Experiments Utilizing JAERI Tandem-Booster Accelerator` at the Tokai Research Establishment. In the symposia, we have mainly discussed the plans of experiments to be done in this joint program. The joint program started in 1994. Several experiments have been made since and some new results have already come up. This symposium `Gamma-ray Spectroscopy utilizing heavy-ion, Photon and RI beams` was held at Tokai Research Establishment of JAERI. Because this symposium is the first occasion after the program started, the first purpose of the symposium is to present and discuss the experimental results so far obtained using the JAERI Tandem-Booster. The second purpose of the symposium is to discuss new possibilities of gamma-ray spectroscopy using new resources such as RI-beam and Photon-beam. The participants from RIKEN, Tohoku University and JAERI Neutron Science Research Center presented the future plans of experiments with RI-beam at each facility. Compared with these nuclear beams, photon beam provides a completely new tool for the {gamma}-ray spectroscopy, which is achieved by inverse Compton scattering between high-energy electron and laser beams. The 23 of the presented papers are indexed individually. (J.P.N.)

  6. High-power continuous-wave mid-infrared radiation generated by difference frequency mixing of diode-laser-seeded fiber amplifiers and its application to dual-beam spectroscopy

    Science.gov (United States)

    Lancaster, D. G.; Richter, D.; Curl, R. F.; Tittel, F. K.; Goldberg, L.; Koplow, J.

    1999-01-01

    We report the generation of up to 0.7 mW of narrow-linewidth (fiber amplifier and a 1.5-micrometers diode-laser-seeded 0.6-W Er/Yb fiber amplifier in periodically poled LiNbO3. A conversion efficiency of 0.09%/W (0.47 mWW-2 cm-1) was achieved. A room-air CH4 spectrum acquired with a compact 80-m multipass cell and a dual-beam spectroscopic configuration indicates an absorption sensitivity of +/-2.8 x 10(-5) (+/-1 sigma), corresponding to a sub-parts-in-10(9) (ppb) CH4 sensitivity (0.8 ppb).

  7. Overview of applications of Laser-Induced Breakdown Spectroscopy (LIBS)

    International Nuclear Information System (INIS)

    Laser-induced breakdown spectroscopy (LIBS) is a method of performing elemental analyses of solids, liquids, and gases using the microplasma produced by a focused laser pulse. Because the microplasma is formed by optical radiation, LIBS has some important advantages compared to conventional laboratory based analytical methods. Three applications are discussed which use the LIBS method. 6 refs., 8 figs., 2 tabs

  8. Pulsed-laser Pumped Photothermal Deflection Spectroscopy for Liquid Thermal Diffusivity Measurement

    Institute of Scientific and Technical Information of China (English)

    XIAO Liantuan; LI Changyong; ZHANG Linjie; ZHAO Yanting; JIA Suotang; ZHOU Guosheng

    2000-01-01

    The pulsed-laser pumped photothermal deflection spectroscopy (PPDS) is applied to measure liquid thermal diffusivity in a modified collinear configuration. Here the pulsed beam is regarded as in the form of a Dirac delta function. The experiment setup used is described. Measurement result for the thermal diffusivity of a liquid sample(magnta/ethanol saturated solution) is reported. The measurement error is less than 3%.

  9. Effects of laser fluence on silicon modification by four-beam laser interference

    International Nuclear Information System (INIS)

    This paper discusses the effects of laser fluence on silicon modification by four-beam laser interference. In this work, four-beam laser interference was used to pattern single crystal silicon wafers for the fabrication of surface structures, and the number of laser pulses was applied to the process in air. By controlling the parameters of laser irradiation, different shapes of silicon structures were fabricated. The results were obtained with the single laser fluence of 354 mJ/cm2, 495 mJ/cm2, and 637 mJ/cm2, the pulse repetition rate of 10 Hz, the laser exposure pulses of 30, 100, and 300, the laser wavelength of 1064 nm, and the pulse duration of 7–9 ns. The effects of the heat transfer and the radiation of laser interference plasma on silicon wafer surfaces were investigated. The equations of heat flow and radiation effects of laser plasma of interfering patterns in a four-beam laser interference distribution were proposed to describe their impacts on silicon wafer surfaces. The experimental results have shown that the laser fluence has to be properly selected for the fabrication of well-defined surface structures in a four-beam laser interference process. Laser interference patterns can directly fabricate different shape structures for their corresponding applications

  10. Effects of laser fluence on silicon modification by four-beam laser interference

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Le; Li, Dayou [JR3CN and CNM, Changchun University of Science and Technology, Changchun 130022 (China); JR3CN and IRAC, University of Bedfordshire, Luton LU1 3JU (United Kingdom); Wang, Zuobin, E-mail: wangz@cust.edu.cn; Yue, Yong [JR3CN and CNM, Changchun University of Science and Technology, Changchun 130022 (China); JR3CN and IRAC, University of Bedfordshire, Luton LU1 3JU (United Kingdom); DCSSE, Xi' an Jiaotong-Livepool University, Suzhou 215123 (China); Zhang, Jinjin; Yu, Miao; Li, Siwei [JR3CN and CNM, Changchun University of Science and Technology, Changchun 130022 (China)

    2015-12-21

    This paper discusses the effects of laser fluence on silicon modification by four-beam laser interference. In this work, four-beam laser interference was used to pattern single crystal silicon wafers for the fabrication of surface structures, and the number of laser pulses was applied to the process in air. By controlling the parameters of laser irradiation, different shapes of silicon structures were fabricated. The results were obtained with the single laser fluence of 354 mJ/cm{sup 2}, 495 mJ/cm{sup 2}, and 637 mJ/cm{sup 2}, the pulse repetition rate of 10 Hz, the laser exposure pulses of 30, 100, and 300, the laser wavelength of 1064 nm, and the pulse duration of 7–9 ns. The effects of the heat transfer and the radiation of laser interference plasma on silicon wafer surfaces were investigated. The equations of heat flow and radiation effects of laser plasma of interfering patterns in a four-beam laser interference distribution were proposed to describe their impacts on silicon wafer surfaces. The experimental results have shown that the laser fluence has to be properly selected for the fabrication of well-defined surface structures in a four-beam laser interference process. Laser interference patterns can directly fabricate different shape structures for their corresponding applications.

  11. Laser Doppler instrument measures fluid velocity without reference beam

    Science.gov (United States)

    Bourquin, K. R.; Shigemoto, F. H.

    1971-01-01

    Fluid velocity is measured by focusing laser beam on moving fluid and measuring Doppler shift in frequency which results when radiation is scattered by particles either originally present or deliberately injected into moving fluid.

  12. Vacuum ultraviolet laser induced fluorescence on a Si atomic beam

    Science.gov (United States)

    O'Brian, T. R.; Lawler, J. E.

    1991-01-01

    A broadly applicable vacuum ultraviolet experiment is described for measuring radiative lifetimes of neutral and singly-ionized atoms in a beam environment to 5-percent accuracy using laser induced fluorescence. First results for neutral Si are reported.

  13. Laser beam propagation generation and propagation of customized light

    CERN Document Server

    Forbes, Andrew

    2014-01-01

    ""The text is easy to read and is accompanied by beautiful illustrations. It is an excellent book for anyone working in laser beam propagation and an asset for any library.""-Optics & Photonics News, July 2014

  14. Laser fluorescence spectroscopy of sputtered uranium atoms

    International Nuclear Information System (INIS)

    Laser induced fluorescence (LIF) spectroscopy was used to study the sputtering of 99.8% 238U metal foil when bombarded by normally incident 500 to 3000 eV Ne+, Ar+, Kr+, and O2+. A three-level atom model of the LIF processes is developed to interpret the observed fluorescent emission from the sputtered species. The model shows that close attention must be paid to the conditions under which the experiment is carried out as well as to the details of the collision cascade theory of sputtering. Rigorous analysis shows that when properly applied, LIF can be used to investigate the predictions of sputtering theory as regards energy distributions of sputtered particles and for the determination of sputtering yields. The possibility that thermal emission may occur during sputtering can also be tested using the proposed model. It is shown that the velocity distribution (either the number density or flux density distribution, depending upon the experimental conditions) of the sputtered particles can be determined using the LIF technique and that this information can be used to obtain a description of the basic sputtering mechanisms. These matters are discussed using the U-atom fluorescence measurements as a basis. The relative sputtering yields for various incident ions on uranium were also measured for the first time using the LIF technique. A surprisingly high fraction of the sputtered uranium atoms were found to occupy the low lying metastable energy levels of U(I). The population of the sputtered metastable atoms were found approximately to obey a Boltzman distribution with an effective temperature of 920 +- 1000K. 41 references

  15. Infrared diode laser spectroscopy of lithium hydride

    International Nuclear Information System (INIS)

    The fundamental and hot bands of the vibration--rotation transitions of 6 LiH, 7 LiH, 6 LiD, and 7 LiD were observed by infrared diode laser spectroscopy at Doppler-limited resolution. Lithium hydride molecules were produced by the reaction of the Li vapor with hydrogen at elevated temperatures. Some 40 transitions were observed and, after combined with submillimeter-wave spectra reported by G. M. Plummer et al. [J. Chem. Phys. 81, 4893 (1984)], were analyzed to yield Dunham-type constants with accuracies more than an order of magnitude higher than those published in the literature. It was clearly demonstrated that the Born--Oppenheimer approximation did not hold, and some parameters representing the breakdown were evaluated. The Born--Oppenheimer internuclear distance r/sup BO//sub e/ was derived to be 1.594 914 26 (59) A, where a new value of Planck's constant recommended by CODATA was employed. The relative intensity of absorption lines was measured to determine the ratio of the permanent dipole moment to its first derivative with respect to the internuclear distance: μ/sub e/ [(partialμpartialr)/sub e/ r/sub e/ ] = 1.743(86). The pressure broadening parameter Δν/sub p/ P was determined to be 6.40 (22) MHzTorr by measuring the linewidth dependence on the pressure of hydrogen, which was about four times larger than the value for the dipole--quadrupole interaction estimated by Kiefer and Bushkovitch's theory

  16. In situ photoelectron spectroscopy of molecular-beam-epitaxy grown surfaces

    CERN Document Server

    Oshima, M; Okabayashi, J; Ono, K

    2003-01-01

    Two in situ high-resolution synchrotron radiation photoelectron spectroscopy (SRPES) systems combined with a molecular beam epitaxy (MBE) chamber for III-V compound semiconductors and a laser MBE chamber for strongly correlated oxide films, respectively, have been designed and fabricated to analyze intrinsic and surface/interface electronic structures of these unique materials. The importance of the in situ SRPES has been demonstrated by the results of 1) Si surface nanostructures, 2) GaAs surfaces/interfaces and nanostructures, 3) MnAs magnetic nanostructures, and 4) strongly-correlated La sub 1 sub - sub x Sr sub x MnO sub 3 surfaces/interfaces and superstructures.

  17. Laser induced incandescence and laser induced breakdown spectroscopy based sensor development

    Science.gov (United States)

    Eseller, Kemal Efe

    In this doctoral dissertation, two laser-based sensors were evaluated for different applications. Laser Induced Incandescence (LII) is a technique which can provide non-intrusive quantitative measurement of soot and it provides a unique diagnostic tool to characterize engine performance. Since LII is linearly proportional to the soot volume fraction, it can provide in situ, real time measurement of soot volume fraction with high temporal and spatial resolution. LII has the capability to characterize soot formation during combustion. The soot volume fraction from both flames and a soot generator was investigated with LII. The effects of experimental parameters, such as laser fluence, gate delay, gate width and various laser beam focusing, on LII signal was studied. Laser Induced Breakdown Spectroscopy (LIBS), a diagnostic tool for in situ elemental analysis, has been evaluated for on-line, simultaneous, multi-species impurity monitoring in hydrogen. LIBS spectra with different impurity levels of nitrogen, argon, and oxygen were recorded and the intensity of the spectral lines of Ar, O, N, and H observed were used to form calibration plots for impurities in hydrogen measurements. An ungated detection method for LIBS has been developed and applied to equivalence ratio measurements of CH4/air and biofuel/air. LIBS has also been used to quantitatively analyze the composition of a slurry sample. The quenching effect of water in slurry samples causes low LIBS signal quality with poor sensitivity. Univariate and multivariate calibration was performed on LIBS spectra of dried slurry samples for elemental analysis of Mg, Si and Fe. Calibration results show that the dried slurry samples give good correlation between spectral intensity and elemental concentration.

  18. Frequency modulation spectroscopy with a terahertz quantum-cascade laser

    OpenAIRE

    Eichholz, René; Richter, Heiko; Wienold, Martin; Schrottke, Lutz; Grahn, H. T.; Hübers, H. -W.

    2014-01-01

    Many physical phenomena have characteristic energies, which correspond to terahertz (THz) frequencies. For example, high-resolution spectroscopy allows for the investigation of the structure and the energy levels of molecules and atoms. THz quantum-cascade lasers (QCLs) are promising radiation sources for such a type of spectroscopy, because they are frequency tunable, and they exhibit mW output powers as well as a narrow line width. So far, absorption spectroscopy with QCLs employed modulati...

  19. Beam propagation considerations in the Aurora laser system

    International Nuclear Information System (INIS)

    Aurora is a high-power KrF laser system now being constructed for inertial confinement fusion (ICF) studies. It will use optical angular multiplexing and serial amplification by electron-beam-driven KrF amplifiers to deliver a stacked, multikilojoule 5-ns-duration laser pulse to ICF targets. The requirements of angular multiplexing KrF lasers at the multikilojoule level dictate path lengths on the order of 1 km. The inherent complicated path crossings produced by angular multiplexing and pulse stacking do not allow isolation of individual beam lines, so the optical quality of the long beam paths must be controlled. Propagation of the 248-nm light beams over long paths in air is affected by scattering, absorption thermal gradients and turbulence, beam alignment, and control and optical component figure errors

  20. Dual-Beam Atom Laser Driven by Spinor Dynamics

    Science.gov (United States)

    Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Aveline, David

    2007-01-01

    An atom laser now undergoing development simultaneously generates two pulsed beams of correlated Rb-87 atoms. (An atom laser is a source of atoms in beams characterized by coherent matter waves, analogous to a conventional laser, which is a source of coherent light waves.) The pumping mechanism of this atom laser is based on spinor dynamics in a Bose-Einstein condensate. By virtue of the angular-momentum conserving collisions that generate the two beams, the number of atoms in one beam is correlated with the number of atoms in the other beam. Such correlations are intimately linked to entanglement and squeezing in atomic ensembles, and atom lasers like this one could be used in exploring related aspects of Bose-Einstein condensates, and as components of future sensors relying on atom interferometry. In this atom-laser apparatus, a Bose-Einstein condensate of about 2 x 10(exp 6) Rb-87 atoms at a temperature of about 120 micro-K is first formed through all-optical means in a relatively weak singlebeam running-wave dipole trap that has been formed by focusing of a CO2-laser beam. By a technique that is established in the art, the trap is loaded from an ultrahigh-vacuum magnetooptical trap that is, itself, loaded via a cold atomic beam from an upstream two-dimensional magneto-optical trap that resides in a rubidium-vapor cell that is differentially pumped from an adjoining vacuum chamber, wherein are performed scientific observations of the beams ultimately generated by the atom laser.

  1. PROPAGATION OF ADAPTIVELY CORRECTED LASER BEAMS THROUGH A TURBULENT ATMOSPHERE

    OpenAIRE

    Bissonnette, L

    1980-01-01

    This paper describes a mathematical model for solving the propagation problem of laser beams travelling in atmospheric turbulence and corrected by adaptive optics. The modeling of the adaptive optics is mathematically simple but sufficiently general to encompass the majority of the existing systems. The method allows the prediction of the average irradiance and the irradiance variance beam profiles for arbitrary scintillation levels. Typical solutions are presented for 3.8 and 10.6 µm laser b...

  2. Intense high-quality medical proton beams via laser fields

    CERN Document Server

    Galow, Benjamin J; Keitel, Christoph H

    2010-01-01

    Simulations based on the coupled relativistic equations of motion show that protons stemming from laserplasma processes can be efficiently post-accelerated employing crossed pulsed laser beams focused to spot radii on the order of the laser wavelength. We demonstrate that the crossed beams produce quasi-monoenergetic accelerated protons with kinetic energies exceeding 200 MeV, small energy spreads of about 1% and high densities as required for hadron cancer therapy.

  3. Theoretical tools for atom-laser-beam propagation

    OpenAIRE

    Riou, Jean-Félix; Le Coq, Yann; Impens, François; Guerin, William; Bordé, Christian,; Aspect, Alain; Bouyer, Philippe

    2008-01-01

    We present a theoretical model for the propagation of non self-interacting atom laser beams. We start from a general propagation integral equation, and we use the same approximations as in photon optics to derive tools to calculate the atom laser beam propagation. We discuss the approximations that allow to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce...

  4. Spectroscopic study of atomic beams generated by laser ablation of multi-layer targets

    International Nuclear Information System (INIS)

    An experiment is described where Li- and Al-beams were generated by ablation of thin, multi-layer targets using a Q-Switched ruby laser with a total energy density up to 30 Jcm-2. Measurements using laser induced fluorescence and mass spectroscopy were combined to analyse the energy- and density distribution and the temporal structure of the beams. The maximum energy turned out to be several eV for Li and several 10 eV for Al with a peak density in the range of 1010 cm-3 for both Li and Al. The targets were analysed by optical microscopy and secondary ion mass spectroscopy providing information about the size of the spots and the structure of the metal film before and after the ablation experiment. (orig.)

  5. A comparison of the physics of Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW), and Laser Beam Welding (LBW)

    Science.gov (United States)

    Nunes, A. C., Jr.

    1985-01-01

    The physics governing the applicability and limitations of gas tungsten arc (GTA), electron beam (EB), and laser beam (LB) welding are compared. An appendix on the selection of laser welding systems is included.

  6. Laser steering of particle beams: refraction and reflection of particle beams

    International Nuclear Information System (INIS)

    The co-propagation of an intense particle beam with an ionizing laser beam in a working gas/plasma is considered. When the axes of the laser and particle beam are not aligned, then asymmetric plasma lensing results in a net dipole field acting on the particle beam. The particle beam can be steered or bent (as well as focused) by steering the laser. An analogy is made between the bending of the particle beam by collective effects at a plasma boundary and the refraction or reflection of light at an interface. This mechanism of particle steering may be of interest in applications for which permanent magnets are inconvenient or a fast turn on is required. 3-D particle-in-cell simulations and relevance to a recent experiment are discussed

  7. Disintegration of urinary calculi by laser beam: drilling experiment in extracted urinary stones.

    Science.gov (United States)

    Tanahashi, Y; Orikasa, S; Chiba, R; Tahira, K; Fukatsu, T; Miyakawa, T

    1979-06-01

    Disintegration of urinary calculi was attempted by the use of laser beam. As a first step, drilling of extracted urinary stones was attempted using a continuous wave CO2 laser and a pulse ruby laser. Stones were drilled easily by either laser beam. The power around 10 W of continuous CO2 laser beam was sufficient to drill through the stone. PMID:462477

  8. Frequency Comb Assisted Broadband Precision Spectroscopy with Cascaded Diode Lasers

    CERN Document Server

    Liu, Junqiu; Pfeiffer, Martin H P; Kordts, Arne; Kamel, Ayman N; Guo, Hairun; Geiselmann, Michael; Kippenberg, Tobias J

    2016-01-01

    Frequency comb assisted diode laser spectroscopy, employing both the accuracy of an optical frequency comb and the broad wavelength tuning range of a tunable diode laser, has been widely used in many applications. In this letter we present a novel method using cascaded frequency agile diode lasers, which allows extending the measurement bandwidth to 37.4 THz (1355 to 1630 nm) at MHz resolution with scanning speeds above 1 THz/s. It is demonstrated as a useful tool to characterize a broadband spectrum for molecular spectroscopy and in particular it enables to characterize the dispersion of integrated microresonators up to the fourth order.

  9. Quantum interference shifts in laser spectroscopy with elliptical polarization

    CERN Document Server

    Amaro, Pedro; Safari, Laleh; Antognini, Aldo; Indelicato, Paul; Pohl, Randolf; Santos, José Paulo

    2015-01-01

    We investigate the quantum interference shifts between energetically close states, where the state structure is observed by laser spectroscopy. We report a compact and analytical expression that models the quantum interference induced shift for any admixture of circular polarization of the incident laser and angle of observation. An experimental scenario free of quantum interference can thus be predicted with this formula. Although, this study is exemplified here for muonic deuterium, it can be applied to any other laser spectroscopy measurement of $ns-n'p$ frequencies of a nonrelativistic atomic system, via a $ns\\rightarrow n'p \\rightarrow n"s $ scheme.

  10. Laser induced breakdown spectroscopy stratigraphic characterization of multilayered painted surfaces

    Science.gov (United States)

    Staicu, A.; Apostol, I.; Pascu, A.; Iordache, I.; Damian, V.; Pascu, M. L.

    2012-08-01

    Laser spectroscopy techniques are modern and competitive methods for elemental analysis. Laser induced breakdown spectroscopy (LIBS), due to its advantages as minimally invasive method that provides real time monitoring and selectivity, is a suitable tool to analyze sample composition. Based on the known emission spectra of heavy metals such as Pb, Zn, Au, Ca, a stratigraphic study regarding the identification of the painting layers content of different mock-up samples was performed. LIBS was used to monitor the laser induced stepwise selective removal of the painting layers and to analyze their composition. The obtained LIBS spectra were correlated with profilometric measurements.

  11. Polarization/Spatial Combining of Laser-Diode Pump Beams

    Science.gov (United States)

    Gelsinger, Paul; Liu, Duncan

    2008-01-01

    A breadboard version of an optical beam combiner is depicted which make it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. The output of each laser diode has a single-mode profile in the meridional plane containing an axis denoted the 'fast' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis. One of the purposes served by the beam-combining optics is to reduce the fast-axis numerical aperture (NA) of the laser-diode output to match the NA of the optical fiber. Along the slow axis, the unmodified laser-diode NA is already well matched to the fiber optic NA, so no further slow-axis beam shaping is needed. In this beam combiner, the laser-diode outputs are collimated by aspherical lenses, then half-wave plates and polarizing beam splitters are used to combine the four collimated beams into two beams. Spatial combination of the two beams and coupling into the optical fiber is effected by use of anamorphic prisms, mirrors, and a focusing lens. The anamorphic prisms are critical elements in the NA-matching scheme, in that they reduce the fast-axis beam width to 1/6 of its original values. Inasmuch as no slow-axis beam shaping is needed, the collimating and focusing lenses are matched for 1:1 iumaging. Because these lenses are well corrected for infinite conjugates the combiner offers diffraction-limited performance along both the fast and slow axes.

  12. Laser-induced breakdown spectroscopy analysis of asbestos

    International Nuclear Information System (INIS)

    Laser-induced breakdown spectroscopy was applied to test the possibility of detecting and identifying asbestos in different samples in view of the perspective at field operation without sample preparation which is peculiar to this technique. Several like-resin materials were first investigated by laser-induced breakdown spectroscopy, in order to find an asbestos container assuring safe laboratory operation during the material characterization aimed to identify indicators suitable for a quick identification on field. Successively, spectra of asbestos samples of both in serpentine and amphibole forms were measured and the variability in elemental composition was calculated from the emission spectra. Ratios of intensities of characteristic elements were tested as indicators for asbestos recognition. Laser-induced breakdown spectroscopy results were compared with those obtained by analyzing the same asbestos samples with a scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy, a good correlation was found for Mg/Si and Fe/Si, thus showing the capability of laser-induced breakdown spectroscopy as a diagnostic tool for this category of materials. In particular, it was demonstrated that the method based on two indicators derived from laser-induced breakdown spectroscopy intensity ratios allows to discriminate between asbestos and cements in single shot measurements suitable to field operation

  13. Generation of monoenergetic ion beams with a laser accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Pfotenhauer, Sebastian M.

    2009-01-29

    A method for the generation of monoenergetic proton and ion beams from a laser-based particle accelerator is presented. This method utilizes the unique space-charge effects occurring during relativistic laser-plasma interactions on solid targets in combination with a dot-like particle source. Due to this unique interaction geometry, MeV proton beams with an intrinsically narrow energy spectrum were obtained, for the first time, from a micrometer-scale laser accelerator. Over the past three years, the acceleration scheme has been consistently improved to enhance both the maximum particle energy and the reliability of the setup. The achieved degree of reliability allowed to derive the first scaling laws specifically for monoenergetic proton beams. Furthermore, the acceleration scheme was expanded on other target materials, enabling the generation of monoenergetic carbon beams. The experimental work was strongly supported by the parallel development of a complex theoretical model, which fully accounts for the observations and is in excellent agreement with numerical simulations. The presented results have an extraordinarily broad scope way beyond the current thesis: The availability of monoenergetic ion beams from a compact laser-plasma beam source - in conjunction with the unique properties of laser-produced particle beams - addresses a number of outstanding applications in fundamental research, material science and medical physics, and will help to shape a new generation of accelerators. (orig.)

  14. Generation of monoenergetic ion beams with a laser accelerator

    International Nuclear Information System (INIS)

    A method for the generation of monoenergetic proton and ion beams from a laser-based particle accelerator is presented. This method utilizes the unique space-charge effects occurring during relativistic laser-plasma interactions on solid targets in combination with a dot-like particle source. Due to this unique interaction geometry, MeV proton beams with an intrinsically narrow energy spectrum were obtained, for the first time, from a micrometer-scale laser accelerator. Over the past three years, the acceleration scheme has been consistently improved to enhance both the maximum particle energy and the reliability of the setup. The achieved degree of reliability allowed to derive the first scaling laws specifically for monoenergetic proton beams. Furthermore, the acceleration scheme was expanded on other target materials, enabling the generation of monoenergetic carbon beams. The experimental work was strongly supported by the parallel development of a complex theoretical model, which fully accounts for the observations and is in excellent agreement with numerical simulations. The presented results have an extraordinarily broad scope way beyond the current thesis: The availability of monoenergetic ion beams from a compact laser-plasma beam source - in conjunction with the unique properties of laser-produced particle beams - addresses a number of outstanding applications in fundamental research, material science and medical physics, and will help to shape a new generation of accelerators. (orig.)

  15. Terahertz multi-heterodyne spectroscopy using laser frequency combs

    CERN Document Server

    Yang, Yang; Hayton, Darren J; Gao, Jian-Rong; Reno, John L; Hu, Qing

    2016-01-01

    Frequency combs based on terahertz quantum cascade lasers feature broadband coverage and high output powers in a compact package, making them an attractive option for broadband spectroscopy. Here, we demonstrate the first multi-heterodyne spectroscopy using two terahertz quantum cascade laser combs. With just 100 $\\mu$s of integration time, we achieve peak signal-to-noise ratios exceeding 60 dB and a spectral coverage greater than 250 GHz centered at 2.8 THz. Even with room-temperature detectors we are able to achieve peak signal-to-noise ratios of 50 dB, and as a proof-of-principle we use these combs to measure the broadband transmission spectrum of etalon samples. Finally, we show that with proper signal processing, it is possible to extend the multi-heterodyne spectroscopy to quantum cascade laser combs operating in pulsed mode, greatly expanding the range of quantum cascade lasers that could be suitable for these techniques.

  16. Vectorial rotating vortex Hankel laser beams

    Science.gov (United States)

    Kotlyar, Victor V.; Kovalev, Alexey A.; Soifer, Victor A.

    2016-09-01

    We propose a generalization of spherical waves in the form of linearly polarized beams with embedded optical vortices. The source of these beams is an infinitely narrow light ring with an infinitely small radius. These vectorial beams are obtained based on scalar Hankel beams discovered by the authors recently. We have derived explicit relations for complex amplitudes of all six components of vectorial vortex Hankel beams. A closed analytical expression for the axial projection of the orbital angular momentum density in far field has been obtained. We also showed that the intensity distribution of the electric vector rotates by 90 degrees upon the beam propagation in near field.

  17. Study on laser beam welding technology for nuclear power plants

    International Nuclear Information System (INIS)

    Laser beam welding is one of the jointing processes by irradiating laser beam on the material surface locally and widely used at various industrial fields. Toshiba has developed various laser-based maintenance and repair technologies and already applied them to several existing nuclear power plants. Laser cladding is a technique to weld the corrosion resistant metal onto a substrate surface by feeding filler wire to improve the corrosion resistance. Temper-bead welding is the heat input process to provide the desired microstructure properties of welded low alloy steels without post weld heat treatment, by inducing proper heat cycle during laser welding. Both laser welding technologies would be performed underwater by blowing the shielding gas for creating the local dry area. In this report, some evaluation results of material characteristics by temper-bead welding to target at Reactor Coolant System nozzle of PWR are presented. (author)

  18. Modeling beam propagation and frequency conversion for the beamlet laser

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, J.M.

    1996-06-01

    The development of the Beamlet laser has involved extensive and detailed modeling of laser performance and beam propagation to: (1) predict the performance limits of the laser, (2) select system configurations with higher performance, (3) analyze experiments and provide guidance for subsequent laser shots, and (4) design optical components and establish component manufacturing specifications. In contrast to modeling efforts of previous laser systems such as Nova, those for Beamlet include as much measured optical characterization data as possible. This article concentrates on modeling of beam propagation in the Beamlet laser system, including the frequency converter, and compares modeling predictions with experimental results for several Beamlet shots. It briefly describes the workstation-based propagation and frequency conversion codes used to accomplish modeling of the Beamlet.

  19. A high brightness electron beam for Free Electron Lasers

    NARCIS (Netherlands)

    Oerle, van Bartholomeus Mathias

    1997-01-01

    In a free electron laser, coherent radiation is generated by letting an electron beam propagate through an alternating magnetic field. The magnetic field is created by a linear array of magnets, which is called an undulator or a wiggler. The wavelength of the laser radiation depends on the amplitude

  20. Cold atom dynamics in crossed laser beam waveguides

    CERN Document Server

    Torrontegui, E; Ruschhaupt, A; Guéry-Odelin, D; Muga, J G

    2010-01-01

    We study the dynamics of neutral cold atoms in an $L$-shaped crossed-beam optical waveguide formed by two perpendicular red-detuned lasers of different intensities and a blue-detuned laser at the corner. Complemented with a vibrational cooling process this setting works as a one-way device or "atom diode".

  1. Phase control and beam steering of semiconductor laser arrays

    Science.gov (United States)

    Katz, J.

    1982-01-01

    The operational principles and a possible device configuration of one dimensional monolithically integrated semiconductor laser arrays are described. The output beam of the array can be electronically steered. Devices of the type can find applications in optical communication systems where the power levels needed are above the capability of a single laser device.

  2. Fabrication of Beam Homogenizers in Quartz by Laser Micromachining

    Energy Technology Data Exchange (ETDEWEB)

    Kopitkovas, G.; Lippert, T.; David, C.; Gobrecht, J.; Wokaun, A.

    2004-03-01

    A one step micromachining process, which utilizes laser assisted chemical wet etching and projection of a diffractive gray tone phase masks is applied to fabricate 3 - dimensional microstructures (such as planoconvex or Fresnel microlenses) in UV transparent materials. Arrays of microlenses in quartz are tested as a beam homogenizers for quadrupled Nd:YAG laser. (author)

  3. Laser spectroscopy of trapped thorium ions

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Sancho, Oscar-Andrey; Okhapkin, Maxim; Zimmermann, Kai; Tamm, Christian; Peik, Ekkehard [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Taichenachev, Alexey; Yudin, Valeriy [Institute of Laser Physics, Siberian Branch of RAS, Novosibirsk 630090 (Russian Federation)

    2011-07-01

    In our experiment more than 10{sup 5} {sup 232}Th{sup +} ions are stored in a linear Paul trap after creation by laser ablation from thorium metal. Single-frequency laser excitation in the complex spectrum of Th{sup +} poses the problem that spontaneous decay populates a number of metastable levels that are decoupled from the laser. Helium and Argon buffer gas are used for collisional cooling and quenching of those levels. We observe laser excitation of the strong resonance line at 401.9 nm with an extended-cavity diode laser and laser excitation of several other transitions around 400 nm and 270 nm with harmonics of a pico-second Ti:Sa laser. In a theoretical analysis we approximate the dense electronic level structure of Th{sup +} ions by just four levels: the ground state and an excited state are coupled by the primary laser, one metastable state is depopulated by a repumper laser and one level by collisions only. The model agrees with experimental results for the fluorescence rate as a function of the laser intensities and can be used to deduce populations and quenching rates. First investigations on two-photon excitation of the Th{sup +} electron shell to the energy range 7.8 eV of the nuclear transition of {sup 229}Th are in progress.

  4. Formation of optical vortices using coherent laser beam arrays

    Science.gov (United States)

    Wang, Li-Gang; Wang, Li-Qin; Zhu, Shi-Yao

    2009-03-01

    We present a proposal to generate an optical vortex beam by using the coherent-superposition of multi-beams in a radially symmetric configuration. In terms of the generalized Huygens-Fresnel diffraction integral, we have derived the general propagation expression for the coherent radial arrays of laser beams. Using the derived formulae, we have analyzed the effects of the beamlet number N, the separation distance ρ of the beamlets and the topological charge m on the intensity and phase distributions of the resultant beams. Our simulation results show that optical vortices could be efficiently generated due to the coherent-superposition effect of all beamlets, during the propagation process of the coherent radial array of laser beams with the initial well-organized phase distributions through the free space. In the focusing system, the resultant beam near the focusing plane has the strong rotational effect with the phase helicity.

  5. Digital Controller For Laser-Beam-Steering Subsystem

    Science.gov (United States)

    Ansari, Homayoon

    1995-01-01

    Report presents additional information about proposed apparatus described in "Beam-Steering Subsystem for Laser Communication" (NPO-19069). Discusses design of digital beam-steering control subsystem and, in particular, that part of design pertaining to digital compensation for frequency response of steering mirror.

  6. Simple Scheme for Variable High Power Laser Beam Attenuation

    OpenAIRE

    Bialkowski, Stephen E.

    1987-01-01

    A venetian style infrared attenuator placed prior to a pinhole spatial filter results in variable high‐power laser attenuation. This attenuation scheme has a wide dynamic range, results in high‐quality Gaussian beams, does not introduce beam walk‐off error, and is independent of polarization.

  7. Multiple quasi-monoenergetic electron beams from laser-wakefield acceleration with spatially structured laser pulse

    International Nuclear Information System (INIS)

    By adjusting the focus geometry of a spatially structured laser pulse, single, double, and treble quasi-monoenergetic electron beams were generated, respectively, in laser-wakefield acceleration. Single electron beam was produced as focusing the laser pulse to a single spot. While focusing the laser pulse to two spots that are approximately equal in energy and size and intense enough to form their own filaments, two electron beams were produced. Moreover, with a proper distance between those two focal spots, three electron beams emerged with a certain probability owing to the superposition of the diffractions of those two spots. The energy spectra of the multiple electron beams are quasi-monoenergetic, which are different from that of the large energy spread beams produced due to the longitudinal multiple-injection in the single bubble

  8. Multiple quasi-monoenergetic electron beams from laser-wakefield acceleration with spatially structured laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y.; Li, M. H.; Li, Y. F.; Wang, J. G.; Tao, M. Z.; Han, Y. J.; Zhao, J. R.; Huang, K.; Yan, W. C.; Ma, J. L.; Li, Y. T. [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Chen, L. M., E-mail: lmchen@iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, D. Z. [Institute of High Energy Physics, CAS, Beijing 100049 (China); Chen, Z. Y. [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621999 (China); Sheng, Z. M. [Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Physics, Scottish Universities Physics Alliance, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Zhang, J. [Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-08-15

    By adjusting the focus geometry of a spatially structured laser pulse, single, double, and treble quasi-monoenergetic electron beams were generated, respectively, in laser-wakefield acceleration. Single electron beam was produced as focusing the laser pulse to a single spot. While focusing the laser pulse to two spots that are approximately equal in energy and size and intense enough to form their own filaments, two electron beams were produced. Moreover, with a proper distance between those two focal spots, three electron beams emerged with a certain probability owing to the superposition of the diffractions of those two spots. The energy spectra of the multiple electron beams are quasi-monoenergetic, which are different from that of the large energy spread beams produced due to the longitudinal multiple-injection in the single bubble.

  9. Time-resolved spectroscopy of solid-state materials using an x-ray laser (Thesis)

    International Nuclear Information System (INIS)

    X-ray laser is a characteristic extreme ultraviolet (EUV) source with short pulse duration of several pico-seconds, narrow spectral width, and high coherence. In particular, x-ray laser with the wavelength of around 13 nm is expected as a powerful tool of various research fields such as EUV lithography because the multilayer mirror with high reflectance is commercially prepared. However, spectroscopic studies of materials optically excited with x-ray laser are few while imaging and interference measurements are intensively studied. In this study, the beam divergence and spatial coherence of x-ray laser was improved and applied to the measurement of time resolved emission spectroscopy of a solid-state material. The beam divergence of the x-ray laser was improved by double target configuration using two gain media. The nickel-like silver x-ray laser at the wavelength of 13.9 nm was improved to be spatially fully coherent beam with the divergence of 0.20 mrad. The number of coherent photons of this beam was 108 per pulse. The narrow divergence allowed us the beam transported by use of a simple mirror system with a small diameter of 1 inch. As an application of the x-ray laser, the UV emission from the zinc oxide (ZnO) single crystal excited by the 13.9 nm x-ray laser was observed and evaluated for EUV scintillator. The time-resolved emission spectra were observed for 13.9 nm excitation and 351 nm excitation. In both the excitation conditions, a prominent fluorescence peak of the ZnO exciton transition was observed at around 380 nm. The time profile at the peak of the spectra could be expressed by a double exponential decay with time constants of 1 ns and 3 ns in the both cases. The lifetimes and intensity ratio of the two decay components in the both cases were almost similar in spite of the huge difference in the excitation photon energy. The response time is sufficiently short for characterizing EUV lithography light sources having several nanoseconds duration. It

  10. Study of a plasma created by an accelerated proton beam for the characterization of a nuclear pumped laser medium

    International Nuclear Information System (INIS)

    Processes leading to laser effect in nuclear induced plasmas can be studied with simulation experiments using charged particles beams. Such an experiment has been performed with a proton beam (2 MeV, 2 μA/cm2) produced by a Van de Graaff accelerator. This beam is an excitation and ionisation source quite comparable to the laser medium source of a reactor experiment. The plasma created in a Ne target (about 100 torrs) containing N2 impurities has been studied: - experimentally using R.F. diagnostics and spectroscopy; - theoretically by calculating the electronic distribution function in the low and medium energy region

  11. Deflection of carbon dioxide laser and helium-neon laser beams in a long-pulse relativistic electron beam diode

    International Nuclear Information System (INIS)

    Deflection of carbon dioxide and helium-neon laser beams has been used to measure plasma and neutral density gradients during the operating mode and after the shorting time of a long-pulse field-emission electron beam diode. Plasma density gradients of (1014--1015) cm-4 were observed throughout the diode during the final microsecond of the 2--3 μs electron beam pulse. The neutral density gradient was less than 1x1018 cm-4 during the electron beam pulse. Upon diode shorting, neutral density gradients increased to (1018--1019) cm-4 over ∼1 μs, and decayed over many microseconds. Plasma density gradients of ∼1015 cm-4 were also observed after shorting. These experiments demonstrate the value of carbon-dioxide laser and helium-neon laser deflection for diagnosing plasma and neutral particles in long-pulse electron beam diodes

  12. Hertzian spectroscopy application to excited states in accelerated ion beams

    International Nuclear Information System (INIS)

    It is shown that accelerated ion beams enables the application of optical hertzian spectrometry methods to be extended to research on the excited states of free ionic systems. The photon beat method has proved especially simple to apply in beam foil geometry because of the unidirectional beam velocity while the beam gas device is suitable for experiments of the energy level crossing type. Only the resonance technique involving direct application of high-frequency magnetic fields poses serious problems because of the high HF powers necessary. So far structure intervals have been measured in ions carrying up to three charges (seven in the special case of Lamb shift measurements) with a precision of a few percent. The interest of these structure studies in free ions is emphasized particularly. The study of hydrogen-like or helium-like ions of high Z allows the fundamental calculations of quantum electrodynamics to be checked with regard to the Lamb shift or the spontaneous emission theory. In more complex electronic systems, optical spectroscopy of accelerated ion beams gives wavelengths with a resolution reaching 10-5, lifetimes with an accuracy better than 10% when the cascade effects are properly studied, and Lande factors with a precision of several % under present technical conditions. The photon beat method concerns hyperfine nuclear effects in light atoms of Z<=20. Another line of research study the hyperfine structure of a given configuration in an isoelectronic sequence

  13. Design of Extended Depth-of-Focus Laser Beams Using Orthogonal Beam Expansions

    Directory of Open Access Journals (Sweden)

    Leonard Bergstein

    2005-06-01

    Full Text Available Laser beams with extended depth of focus have many practical applications, such as scanning printed bar codes. Previous work has concentrated on synthesizing such beams by approximating the nondiffracting Bessel beam solution to the wave equation. In this paper, we introduce an alternate novel synthesis method that is based on maintaining a minimum MTF value (contrast over the largest possible distance. To achieve this, the coefficients of an orthogonal beam expansion are sequentially optimized to this criterion. One of the main advantages of this method is that it can be easily generalized to noncircularly symmetrical beams by the appropriate choice of the beam expansion basis functions. This approach is found to be very useful for applications that involve scanning of the laser beam.

  14. Laser beam complex amplitude measurement by phase diversity

    OpenAIRE

    Védrenne, Nicolas; Mugnier, Laurent M.; Michau, Vincent; Velluet, Marie-Thérèse; Bierent, Rudolph

    2014-01-01

    The control of the optical quality of a laser beam requires a complex amplitude measurement able to deal with strong modulus variations and potentially highly perturbed wavefronts. The method proposed here consists in an extension of phase diversity to complex amplitude measurements that is effective for highly perturbed beams. Named CAMELOT for Complex Amplitude MEasurement by a Likelihood Optimization Tool, it relies on the acquisition and processing of few images of the beam section taken ...

  15. ILC Beam Energy Measurement by means of Laser Compton Backscattering

    OpenAIRE

    Muchnoi, N.; Schreiber, H. J.; Viti, M

    2008-01-01

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitiv...

  16. SbSI nanocrystal formation in As–Sb–S–I glass under laser beam

    International Nuclear Information System (INIS)

    Highlights: ► As–Sb–S–I glasses are obtained by co-melting of As2S3 and SbSI. ► The glass structure and composition are confirmed by SEM, EDX, and Raman studies. ► Laser-induced crystallization of SbSI from the glass is observed by Raman spectroscopy. -- Abstract: As–Sb–S–I glasses are obtained by co-melting of As2S3 and SbSI in a broad compositional interval. Their structure and composition are confirmed by the studies of scanning electron microscopy, energy dispersive X-ray spectroscopy, and micro-Raman scattering. Laser-induced crystallization of SbSI crystallites from the glass matrix is observed in the course of the micro-Raman measurement as a result of local laser beam heating.

  17. Vacuum laser acceleration using a radially polarized CO2 laser beam

    International Nuclear Information System (INIS)

    Utilizing the high-power, radially polarized CO2 laser and high-quality electron beam at the Brookhaven Accelerator Test Facility, a vacuum laser acceleration scheme is proposed. In this scheme, optics configuration is simple, a small focused beam spot size can be easily maintained, and optical damage becomes less important. At least 0.5 GeV/m acceleration gradient is achievable by 1 TW laser power

  18. Laser beam deflection as a probe of laser ablation of materials

    International Nuclear Information System (INIS)

    Helium-neon laser beam deflection is used to study excimer laser ablation of polymers and a YBa2Cu3O7-x superconductor. Density gradients above pulsed laser heated or ablated samples deflect the He-Ne laser beam and this is measured using a position sensitive detector. The technique permits the determination of the laser fluence threshold for ablation both in a vacuum and in air, and the velocity of the ablation products in a vacuum. A model of the thermal deflection at low fluence was developed which enables measurements of thermal diffusivity of the air

  19. beam timing diagnostic for the OMEGA laser facility

    Science.gov (United States)

    Katz, J.; Donaldson, W. R.; Huff, R.; Hill, E. M.; Kelly, J. H.; Kwiatkowski, J.; Brannon, R. B.

    2015-08-01

    The Omega Laser Facility at the University of Rochester's Laboratory for Laser Energetics is a 60-beam system used for inertial confinement fusion experiments. Uniform drive of the target surface requires precise beam timing to achieve accurate power balance. A new diagnostic has been implemented for measuring the relative beam-to-beam arrival time of each of the 60 beamlines. A 900-μm spherical diffuser placed at the target chamber center serves as a quasi-isotropic scattering source that allows a fixed optical detector to view light from any individual beamline. During a beam-timing run, the OMEGA laser is configured to generate frequency-tripled, 351-nm ultraviolet (UV) pulses with energies of ~50 pJ at a repetition rate of 5 Hz. Light from the scattering target is optically relayed to a fast photomultiplier tube and recorded on a digital oscilloscope. A portion of the original infrared (IR) seed pulse is fiber optically delivered to the beam-timing oscilloscope and recorded using a photodiode. By recording the scattered UV pulse and the IR seed on the same oscilloscope trace, a jitter-free measurement of the beam's arrival time can be made. Discrepancies in beam timing are corrected by adjusting the total optical path length of the beamlines. Typical variation in the measured arrival times of all 60 OMEGA beams after adjustment is <5 ps root mean square

  20. New method of beam bunching in free-ion lasers

    International Nuclear Information System (INIS)

    An effective ion beam bunching method is suggested. This method is based on a selective interaction of line spectrum laser light (e.g. axial mode structure light) with non-fully stripped ion beam cooled in a storage rings, arranging the ion beam in layers in radial direction of an energy-longitudinal coordinate plane and following rotation of the beam at the right angle after switching on the RF cavity or undulator grouper/buncher. Laser cooling of the ion beam can be used at this position after switching off the resonator to decrease the energy spread caused by accelerating field of the resonator. A relativistic multilayer ion mirror will be produced this way. Both monochromatic laser beams and intermediate monochromaticity and bandwidth light sources of spontaneous incoherent radiation can be used for production of hard and high power electromagnetic radiation by reflection from this mirror. The reflectivity of the mirror is rather high because of the cross-section of the backward Rayleigh scattering of photon light by non-fully stripped relativistic ions (∼λ2) is much greater (∼ 10 divided-by 15 orders) then Thompson one (∼ re2). This position is valid even in the case of non-monochromatic laser light (Δω/ω ∼ 10-4). Ion cooling both in longitudinal plane and three-dimensional radiation ion cooling had been proposed based on this observation. The using of these cooling techniques will permit to store high current and low emittance relativistic ion beams in storage rings. The bunched ion beam can be used in ordinary Free-Ion Lasers as well. After bunching the ion beam can be extracted from the storage ring in this case. Storage rings with zero momentum compaction function will permit to keep bunching of the ion beam for a long time

  1. New method of beam bunching in free-ion lasers

    Energy Technology Data Exchange (ETDEWEB)

    Bessonov, E.G. [Lebedev Physics Institute, Moscow (Russian Federation)

    1995-12-31

    An effective ion beam bunching method is suggested. This method is based on a selective interaction of line spectrum laser light (e.g. axial mode structure light) with non-fully stripped ion beam cooled in a storage rings, arranging the ion beam in layers in radial direction of an energy-longitudinal coordinate plane and following rotation of the beam at the right angle after switching on the RF cavity or undulator grouper/buncher. Laser cooling of the ion beam can be used at this position after switching off the resonator to decrease the energy spread caused by accelerating field of the resonator. A relativistic multilayer ion mirror will be produced this way. Both monochromatic laser beams and intermediate monochromaticity and bandwidth light sources of spontaneous incoherent radiation can be used for production of hard and high power electromagnetic radiation by reflection from this mirror. The reflectivity of the mirror is rather high because of the cross-section of the backward Rayleigh scattering of photon light by non-fully stripped relativistic ions ({approximately}{lambda}{sup 2}) is much greater ({approximately} 10{divided_by}15 orders) then Thompson one ({approximately} r{sub e}{sup 2}). This position is valid even in the case of non-monochromatic laser light ({Delta}{omega}/{omega} {approximately} 10{sup -4}). Ion cooling both in longitudinal plane and three-dimensional radiation ion cooling had been proposed based on this observation. The using of these cooling techniques will permit to store high current and low emittance relativistic ion beams in storage rings. The bunched ion beam can be used in ordinary Free-Ion Lasers as well. After bunching the ion beam can be extracted from the storage ring in this case. Storage rings with zero momentum compaction function will permit to keep bunching of the ion beam for a long time.

  2. Structural defects in laser- and electron-beam annealed silicon

    International Nuclear Information System (INIS)

    Laser and electron beam pulses provide almost an ideal source of heat by which thin layers of semiconductors can be rapidly melted and solidified with heating and cooling rates exceeding 1080C/sec. Microstructural modifications obtained as a function of laser parameters are examined and it is shown that both laser and electron beam pulses can be used to remove displacement damage, dislocations, dislocation loops and precipitates. Annealing of defects underneath the oxide layers in silicon is possible within a narrow energy window. The formation of cellular structure provides a rather clear evidence of melting which leads to segregation and supercooling, and subsequent cell formation

  3. Measurement system with high accuracy for laser beam quality.

    Science.gov (United States)

    Ke, Yi; Zeng, Ciling; Xie, Peiyuan; Jiang, Qingshan; Liang, Ke; Yang, Zhenyu; Zhao, Ming

    2015-05-20

    Presently, most of the laser beam quality measurement system collimates the optical path manually with low efficiency and low repeatability. To solve these problems, this paper proposed a new collimated method to improve the reliability and accuracy of the measurement results. The system accuracy controlled the position of the mirror to change laser beam propagation direction, which can realize the beam perpendicularly incident to the photosurface of camera. The experiment results show that the proposed system has good repeatability and the measuring deviation of M2 factor is less than 0.6%. PMID:26192526

  4. Intense ion beams accelerated by relativistic laser plasmas

    Science.gov (United States)

    Roth, Markus; Cowan, Thomas E.; Gauthier, Jean-Claude J.; Allen, Matthew; Audebert, Patrick; Blazevic, Abel; Fuchs, Julien; Geissel, Matthias; Hegelich, Manuel; Karsch, S.; Meyer-ter-Vehn, Jurgen; Pukhov, Alexander; Schlegel, Theodor

    2001-12-01

    We have studied the influence of the target properties on laser-accelerated proton and ion beams generated by the LULI multi-terawatt laser. A strong dependence of the ion emission on the surface conditions, conductivity, shape and material of the thin foil targets were observed. We have performed a full characterization of the ion beam using magnetic spectrometers, Thompson parabolas, radiochromic film and nuclear activation techniques. The strong dependence of the ion beam acceleration on the conditions on the target back surface was found in agreement with theoretical predictions based on the target normal sheath acceleration (TNSA) mechanism. Proton kinetic energies up to 25 MeV have been observed.

  5. Generation and transport of laser accelerated ion beams

    International Nuclear Information System (INIS)

    Currently the LIGHT- Project (Laser Ion Generation, Handling and Transport) is performed at the GSI Helmholtzzentrum fuer Schwerionenforschung GmbH Darmstadt. Within this project, intense proton beams are generated by laser acceleration, using the TNSA mechanism. After the laser acceleration the protons are transported through the beam pipe by a pulsed power solenoid. To study the transport a VORPAL 3D simulation is compared with CST simulation. A criterion as a function of beam parameters was worked out, to rate the importance of space charge. Furthermore, an exemplary comparison of the solenoid with a magnetic quadrupole-triplet was carried out. In the further course of the LIGHT-Project, it is planned to generate ion beams with higher kinetic energies, using ultra-thin targets. The acceleration processes that can appear are: RPA (Radiation Pressure Acceleration) and BOA (Break-Out Afterburner). Therefore the transport of an ion distribution will be studied, as it emerges from a RPA acceleration.

  6. Laser spectroscopy: Assessment of research needs for laser technologies applied to advanced spectroscopic methods

    International Nuclear Information System (INIS)

    This report is organized as follows. Section 2 summarizes the current program of DOE's Office of Health and Environmental Research (OHER) and provides some remarks on low laser science and technology could beneficially impact most of the research programs. Section 3 provides a brief global perspective on laser technology and attempts to define important trends in the field. Similarly, Section 4 provides a global perspective on laser spectroscopy and addresses important trends. Thus, Section 5 focuses on the trends in laser technology and spectroscopy which could impact the OHER mission in significant ways and contains the basis for recommendations made in the executive summary. For those with limited familiarity with laser technology and laser spectroscopy, reference is made to Appendix 1 for a list of abbreviations and acronyms. Appendix 2 can serve a useful review or tutorial for those who are not deeply involved with laser spectroscopy. Even those familiar with laser spectroscopy and laser technology may find it useful to know precisely what the authors of this document mean by certain specialized terms and expressions. Finally, a note on the style of referencing may be appropriate. Whenever possible a book or review articles is referenced as the preferred citation. However, we frequently found it useful to reference a number of individual papers of recent origin or those which were not conveniently found in the review articles

  7. Ultraviolet continuous-wave laser source at 205 nm for hydrogen spectroscopy

    Science.gov (United States)

    Galtier, Sandrine; Nez, François; Julien, Lucile; Biraben, François

    This paper reports on the generation of 15 mW of continuous narrow-band laser source at 205 nm. The infra-red light source provided by a Titanium-Sapphire (TiSa) laser is mixed with the fourth harmonic of a Nd:YVO4 laser by the use of a β-barium borate (BBO) non-linear crystal. This highly reliable and powerful ultraviolet (UV) source is an ideal tool for the 1S-3S hydrogen spectroscopy. Moreover, the wide tunability of the TiSa laser combined with this experimental set up makes the generation of bright deep ultra-violet (D-UV) sources possible. In particular, we plan to produce a 194 nm continuous light beam which is necessary to perform the 1S-4S transition in hydrogen.

  8. Doppler-free spectroscopy on Cs D$_1$ line with a dual-frequency laser

    CERN Document Server

    Hafiz, Moustafa Abdel; De Clercq, Emeric; Boudot, Rodolphe

    2016-01-01

    We report on Doppler-free laser spectroscopy in a Cs vapor cell using a dual-frequency laser system tuned on the Cs D$_1$ line. Using counter-propagating beams with crossed linear polarizations, an original sign-reversal of the usual saturated absorption dip and large increase in Doppler-free atomic absorption is observed. This phenomenon is explained by coherent population trapping (CPT) effects. The impact of laser intensity and light polarization on absorption profiles is reported in both single-frequency and dual-frequency regimes. In the latter, frequency stabilization of two diode lasers was performed, yielding a beat-note fractional frequency stability at the level of $3 \\times 10^{-12}$ at 1 s averaging time. These performances are about an order of magnitude better than those obtained using a conventional single-frequency saturated absorption scheme.

  9. Laser-ablated active doping technique for visible spectroscopy measurements on Z.

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Matthew Robert

    2013-09-01

    Visible spectroscopy is a powerful diagnostic, allowing plasma parameters ranging from temperature and density to electric and magnetic fields to be measured. Spectroscopic dopants are commonly introduced to make these measurements. On Z, dopants are introduced passively (i.e. a salt deposited on a current-carrying surface); however, in some cases, passive doping can limit the times and locations at which measurements can be made. Active doping utilizes an auxiliary energy source to disperse the dopant independently from the rest of the experiment. The objective of this LDRD project was to explore laser ablation as a method of actively introducing spectroscopic dopants. Ideally, the laser energy would be delivered to the dopant via fiber optic, which would eliminate the need for time-intensive laser alignments in the Z chamber. Experiments conducted in a light lab to assess the feasibility of fibercoupled and open-beam laser-ablated doping are discussed.

  10. Prospects for high-resolution microwave spectroscopy of methanol in a Stark-deflected molecular beam

    CERN Document Server

    Jansen, Paul; Meng, Congsen; Lees, Ronald M; Janssen, Maurice H M; Ubachs, Wim; Bethlem, Hendrick L

    2013-01-01

    Recently, the extremely sensitive torsion-rotation transitions in methanol have been used to set a tight constraint on a possible variation of the proton-to-electron mass ratio over cosmological time scales. In order to improve this constraint, laboratory data of increased accuracy will be required. Here, we explore the possibility for performing high-resolution spectroscopy on methanol in a Stark-deflected molecular beam. We have calculated the Stark shift of the lower rotational levels in the ground torsion-vibrational state of CH3OH and CD3OH molecules, and have used this to simulate trajectories through a typical molecular beam resonance setup. Furthermore, we have determined the efficiency of non-resonant multi-photon ionization of methanol molecules using a femtosecond laser pulse. The described setup is in principle suited to measure microwave transitions in CH3OH at an accuracy below 10^{-8}.

  11. Beam transport optics for high-power laser systems

    International Nuclear Information System (INIS)

    Beam transport optics receive output energy from the laser cavity and deliver it to the work site. Depending on the application, this may require a few simple elements or large complex systems. Collection of the laser energy depends on the spatial and temporal energy distribution as well as the wavelength and polarization of the laser cavity and output coupler. Transport optics can perform a variety of functions, including beam formatting, frequency doubling, and distribution to one or more work sites while maintaining or even improving the beam quality. The beam may be delivered to work sites as focused spots or images, projected to distant targets, or propagated through various media for sensing or photochemical processing. Design may involve optical modeling of the system, including diffraction effects and thermal management. A Gaussian beam profile is often used for convenience in modeling. When deviations from this ideal profile need to be considered, it is necessary to characterize the laser beam in detail. Design of the transport system requires understanding of the interaction of the laser energy with optical materials and components. Practical considerations include mounting the optics without stress and with the stability suitable for the intended application. Requirements for beam direction, stability, size, shape, and quality dictate the design approach for each specific situation. Attention also must be given to reliability, environmental, and commercial requirements. Damage to optics in high-power laser systems is a common concern. Environmental problems such as atmospheric turbulence, contamination by dust or vapor from the work site or other sources, or absorption of water vapor can directly degrade beam quality. Other potentially significant optical performance effects may result from instability and aging of the optics, temperature, humidity, pressure, transmitted vibration, and contamination from the work site or other sources

  12. TRIGA-SPEC: A setup for mass spectrometry and laser spectroscopy at the research reactor TRIGA Mainz

    OpenAIRE

    Ketelaer, J.; Krämer, J.; Beck, D; Blaum, K.; Block, M.; Eberhardt, K.; Eitel, G.; Ferrer, R.; Geppert, C.; George, S; Herfurth, F.; Ketter, J.; Nagy, Sz.; Neidherr, D.; Neugart, R

    2008-01-01

    The research reactor TRIGA Mainz is an ideal facility to provide neutron-rich nuclides with production rates sufficiently large for mass spectrometric and laser spectroscopic studies. Within the TRIGA-SPEC project, a Penning trap as well as a beam line for collinear laser spectroscopy are being installed. Several new developments will ensure high sensitivity of the trap setup enabling mass measurements even on a single ion. Besides neutron-rich fission products produced in the reactor, also h...

  13. Practical and research aspects of beam-foil spectroscopy

    International Nuclear Information System (INIS)

    The application of a heavy-ion accelerator to research in beam-foil spectroscopy requires certain capital equipment which is somewhat unorthodox when viewed from the standpoint of conventional, low-energy nuclear physics. It is necessary that people who wish to expand their accelerator work to include beam-foil studies understand the nature and cost of such major apparatus. We will survey the equipment needs, starting with the particle analyzer at the output of the accelerator and including the equipment used in a variety of beam-foil experiments. Electronic and computer devices will not be discussed since they are essentially identical with those employed in nuclear studies. Considerable attention will be given to optical spectrometers and spectographs including simple instruments which might be used by a laboratory just getting started in beam-foil research, or which has limited financial resources. Attention will be given to the production and use of the exciter foils. We will then discuss some typical beam-foil experiments having to do with the excitation, detection, and analysis of spectral lines from electronic levels in multiply-ionized atoms, and also with the measurement of the mean lives of such levels. Finally, we will review some of the special properties of the beam-foil light source as regards the population of the magnetic sub-states of a given level. Recent work on the character of the emitted light will be presented. That work will deal specifically with the origin of the polarization of the light. The relevant experiments involve varying the angle between the plane of the exciter foil and the particle velocity. (author)

  14. Towards in-Beam Spectroscopy of the Heaviest Elements

    International Nuclear Information System (INIS)

    New developments in nuclear spectroscopy of prompt emission at the target and decay emission at the focal plane of recoil separators are described here. In-beam γ-ray measurements of even-even nuclei in the rotational superheavy region, 252;254No, have been carried out. These measurements have revealed the properties of the ground state rotational bands. Attempts to measure the properties of odd mass nuclei await the further development of conversion electron spectroscopy , and early results from the SACRED spectrometer used in conjunction with the recoil separator RITU are given here. The future development of sensitive focal plane instruments, to identify decay processes following the radioactive decay of the parent nucleus is also described. (author)

  15. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  16. Nuclear spectroscopy using direct reactions of RI beams

    International Nuclear Information System (INIS)

    The α inelastic scatterings and the (α,t) reaction on exotic nuclei at 50-60 A MeV are discussed. A new multipole decomposition analysis taking into account the angular correlation of decaying process originated from the alignments of the residual nucleus is applied for a study of cluster states in 12Be. The proton transfer reaction on the 12Be nucleus populates a possible proton single-particle state bound by a deformed core in the 13B nucleus of which ground state is spherical.For a new spectroscopy of nuclei using intense RI beams at RIBF, we started the SHARAQ project where a high-resolution SHARAQ spectrometer is being constructed together with a high-resolution secondary beam line. Physics motivation and the specification of the spectrometer are presented

  17. Simultaneous irradiation of laser and ion beams on optical materials

    International Nuclear Information System (INIS)

    A simultaneous irradiation system of laser and ion beams has been developed to investigate ion beam induced luminescence and optical absorption of crystalline α-Al2O3 samples. The luminescence induced by 30 keV Ar+ in visible wavelength region had peaks that were attributed to oxygen vacancies. The optical absorption at 633 nm in wavelength was also measured during the ion irradiation. The amount of optical absorption for the irradiated sample with Q-switched Nd:YAG laser pulses was less than that without the laser pulses. The ion irradiation reduced the threshold level of laser damage on the surface region of the sample, and the laser ablation selectively happened on the ion irradiation region

  18. Kinetic modelling of quantum effects in laser-beam interaction

    CERN Document Server

    Nerush, Evgeny

    2011-01-01

    We present the results of kinetic modelling of quantum effects in laser-beam interaction. In the developed numerical model, electron-positron pair production by hard photons, hard photon emission and the electromagnetic fields generated by the created charged particles are taken into account. Interaction of a relativistic electron beam with a strong laser pulse is analyzed. It is shown that the quantum effects can be important even for moderately intense laser pulses when the number of emitted photons by single electron is not large. Electron-positron pair plasma production in extremely-intense laser field via development of electromagnetic cascades is also studied. The simulation results confirm the prediction of strong laser field absorption in the self-generated electron-positron plasma. It is shown that the self-generated electron-positron plasma can be an efficient source of energetic gamma-quanta.

  19. Direct Electron Acceleration with Radially Polarized Laser Beams

    Directory of Open Access Journals (Sweden)

    Michel Piché

    2013-01-01

    Full Text Available In the past years, there has been a growing interest in innovative applications of radially polarized laser beams. Among them, the particular field of laser-driven electron acceleration has received much attention. Recent developments in high-power infrared laser sources at the INRS Advanced Laser Light Source (Varennes, Qc, Canada allowed the experimental observation of a quasi-monoenergetic 23-keV electron beam produced by a radially polarized laser pulse tightly focused into a low density gas. Theoretical analyses suggest that the production of collimated attosecond electron pulses is within reach of the actual technology. Such an ultrashort electron pulse source would be a unique tool for fundamental and applied research. In this paper, we propose an overview of this emerging topic and expose some of the challenges to meet in the future.

  20. ILC Beam Energy Measurement by means of Laser Compton Backscattering

    CERN Document Server

    Muchnoi, N; Viti, M

    2008-01-01

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of $10^{-4}$ or bette...

  1. Beam simultaneity results in the Helios laser fusion facility

    International Nuclear Information System (INIS)

    The operation of the beam simultaneity system of the 10-kJ, 20-TW, eight-beam Helios CO2 laser experimental fusion facility, which is required to ensure that the eight laser beams arrive at the target within 33 picosec of each other, is discussed. The system measures relative beam path lengths with a resolution of 1 mm based on the comparison of electro-optically modulated signals from a CW CO2 laser injected into the eight beam paths and a reference path and reflected off a reflecting sphere in the target chamber. Signal-to-electrical-noise and signal-to-optical-noise ratios are both greater than 500, with the noise composed of components at 1 and 0.1 Hz in both the reference and beam paths. It is estimated that each optical beam path can be measured to within 3 mm, and that the system can be realigned with less than 3 mm path change. Beam simultaneity is finally limited by dispersive and dynamical effects of the gain medium of the triple pass power amplifiers, which have not yet been measured, but are believed to be compatible with the goal accuracy (10 picosec) and resolution (33 picosec) of the system

  2. Evaluation of two-beam spectroscopy as a plasma diagnostic

    International Nuclear Information System (INIS)

    A two-beam spectroscopy (TBS) system is evaluated theoretically and experimentally. This new spectroscopic technique uses correlations between components of emitted light separated by a small difference in angle of propagation. It is thus a non-perturbing plasma diagnostic which is shown to provide local (as opposed to line-of-sight averaged) information about fluctuations in the density of light sources within a plasma - information not obtainable by the usual spectroscopic methods. The present design is an improvement on earlier systems proposed in a thesis by Rostler

  3. Development of the charge exchange recombination spectroscopy and the beam emission spectroscopy on the EAST tokamak.

    Science.gov (United States)

    Li, Y Y; Fu, J; Lyu, B; Du, X W; Li, C Y; Zhang, Y; Yin, X H; Yu, Y; Wang, Q P; von Hellermann, M; Shi, Y J; Ye, M Y; Wan, B N

    2014-11-01

    Charge eXchange Recombination Spectroscopy (CXRS) and Beam Emission Spectroscopy (BES) diagnostics based on a heating neutral beam have recently been installed on EAST to provide local measurements of ion temperature, velocity, and density. The system design features common light collection optics for CXRS and BES, background channels for the toroidal views, multi-chord viewing sightlines, and high throughput lens-based spectrometers with good signal to noise ratio for high time resolution measurements. Additionally, two spectrometers each has a tunable grating to observe any wavelength of interest are used for the CXRS and one utilizes a fixed-wavelength grating to achieve higher diffraction efficiency for the BES system. A real-time wavelength correction is implemented to achieve a high-accuracy wavelength calibration. Alignment and calibration are performed. Initial performance test results are presented. PMID:25430335

  4. Efficient sub-Doppler transverse laser cooling of an indium atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Ihn

    2009-07-23

    Laser cooled atomic gases and atomic beams are widely studied samples in experimental research in atomic and optical physics. For the application of ultra cold gases as model systems for e.g. quantum many particle systems, the atomic species is not very important. Thus this field is dominated by alkaline, earthalkaline elements which are easily accessible with conventional laser sources and have convenient closed cooling transition. On the other hand, laser cooled atoms may also be interesting for technological applications, for instance for the creation of novel materials by atomic nanofabrication (ANF). There it will be important to use technologically relevant materials. As an example, using group III atoms of the periodical table in ANF may open a route to generate fully 3D structured composite materials. The minimal requirement in such an ANF experiment is the collimation of an atomic beam which is accessible by one dimensional laser cooling. In this dissertation, I describe transverse laser cooling of an Indium atomic beam. For efficient laser cooling on a cycling transition, I have built a tunable, continuous-wave coherent ultraviolet source at 326 nm based on frequency tripling. For this purpose, two independent high power Yb-doped fiber amplifiers for the generation of the fundamental radiation at {lambda}{sub {omega}} = 977 nm have been constructed. I have observed sub-Doppler transverse laser cooling of an Indium atomic beam on a cycling transition of In by introducing a polarization gradient in the linear-perpendicular-linear configuration. The transverse velocity spread of a laser-cooled In atomic beam at full width at half maximum was achieved to be 13.5{+-}3.8 cm/s yielding a full divergence of only 0.48 {+-} 0.13 mrad. In addition, nonlinear spectroscopy of a 3-level, {lambda}-type level system driven by a pump and a probe beam has been investigated in order to understand the absorption line shapes used as a frequency reference in a previous two

  5. Efficient sub-Doppler transverse laser cooling of an indium atomic beam

    International Nuclear Information System (INIS)

    Laser cooled atomic gases and atomic beams are widely studied samples in experimental research in atomic and optical physics. For the application of ultra cold gases as model systems for e.g. quantum many particle systems, the atomic species is not very important. Thus this field is dominated by alkaline, earthalkaline elements which are easily accessible with conventional laser sources and have convenient closed cooling transition. On the other hand, laser cooled atoms may also be interesting for technological applications, for instance for the creation of novel materials by atomic nanofabrication (ANF). There it will be important to use technologically relevant materials. As an example, using group III atoms of the periodical table in ANF may open a route to generate fully 3D structured composite materials. The minimal requirement in such an ANF experiment is the collimation of an atomic beam which is accessible by one dimensional laser cooling. In this dissertation, I describe transverse laser cooling of an Indium atomic beam. For efficient laser cooling on a cycling transition, I have built a tunable, continuous-wave coherent ultraviolet source at 326 nm based on frequency tripling. For this purpose, two independent high power Yb-doped fiber amplifiers for the generation of the fundamental radiation at λω = 977 nm have been constructed. I have observed sub-Doppler transverse laser cooling of an Indium atomic beam on a cycling transition of In by introducing a polarization gradient in the linear-perpendicular-linear configuration. The transverse velocity spread of a laser-cooled In atomic beam at full width at half maximum was achieved to be 13.5±3.8 cm/s yielding a full divergence of only 0.48 ± 0.13 mrad. In addition, nonlinear spectroscopy of a 3-level, Λ-type level system driven by a pump and a probe beam has been investigated in order to understand the absorption line shapes used as a frequency reference in a previous two-color spectroscopy experiment

  6. Full-Duplex Digital Communication on a Single Laser Beam

    Science.gov (United States)

    Hazzard, D. A.; MacCannell, J. A.; Lee, G.; Selves, E. R.; Moore, D.; Payne, J. A.; Garrett, C. D.; Dahlstrom, N.; Shay, T. M.

    2006-01-01

    A proposed free-space optical communication system would operate in a full-duplex mode, using a single constant-power laser beam for transmission and reception of binary signals at both ends of the free-space optical path. The system was conceived for two-way data communication between a ground station and a spacecraft in a low orbit around the Earth. It has been estimated that in this application, a data rate of 10 kb/s could be achieved at a ground-station-to-spacecraft distance of 320 km, using a laser power of only 100 mW. The basic system concept is also applicable to terrestrial free-space optical communications. The system (see figure) would include a diode laser at one end of the link (originally, the ground station) and a liquid-crystal- based retroreflecting modulator at the other end of the link (originally, the spacecraft). At the laser end, the beam to be transmitted would be made to pass through a quarter-wave plate, which would convert its linear polarization to right circular polarization. For transmission of data from the laser end to the retroreflector end, the laser beam would be modulated with subcarrier phase-shift keying (SC-PSK). The transmitted beam would then pass through an aperture- sharing element (ASE) - basically, a mirror with a hole in it, used to separate the paths of the transmitted and received light beams. The transmitted beam would continue outward through a telescope (which, in the original application, would be equipped with a spacecraft-tracking system) that would launch the transmitted beam along the free-space optical path to the retroreflector end.

  7. Beam shaping for laser-based adaptive optics in astronomy

    CERN Document Server

    Béchet, Clémentine; Neichel, Benoit; Fesquet, Vincent; González-Núñez, Héctor; Zúñiga, Sebastián; Escarate, Pedro; Guzman, Dani

    2014-01-01

    The availability and performance of laser-based adaptive optics (AO) systems are strongly dependent on the power and quality of the laser beam before being projected to the sky. Frequent and time-consuming alignment procedures are usually required in the laser systems with free-space optics to optimize the beam. Despite these procedures, significant distortions of the laser beam have been observed during the first two years of operation of the Gemini South multi-conjugate adaptive optics system (GeMS). A beam shaping concept with two deformable mirrors is investigated in order to provide automated optimization of the laser quality for astronomical AO. This study aims at demonstrating the correction of quasi-static aberrations of the laser, in both amplitude and phase, testing a prototype of this two-deformable mirror concept on GeMS. The paper presents the results of the preparatory study before the experimental phase. An algorithm to control amplitude and phase correction, based on phase retrieval techniques...

  8. Initial Results of Optical Vortex Laser Absorption Spectroscopy in the HYPER-I Device

    Science.gov (United States)

    Yoshimura, Shinji; Asai, Shoma; Aramaki, Mitsutoshi; Terasaka, Kenichiro; Ozawa, Naoya; Tanaka, Masayoshi; Morisaki, Tomohiro

    2015-11-01

    Optical vortex beams have a potential to make a new Doppler measurement, because not only parallel but perpendicular movement of atoms against the beam axis causes the Doppler shift of their resonant absorption frequency. As the first step of a proof-of-principle experiment, we have performed the optical vortex laser absorption spectroscopy for metastable argon neutrals in an ECR plasma produced in the HYPER-I device at the National Institute for Fusion Science, Japan. An external cavity diode laser (TOPTICA, DL100) of which center wavelength was 696.735 nm in vacuum was used for the light source. The Hermite-Gaussian (HG) beam was converted into the Laguerre-Gaussian (LG) beam (optical vortex) by a computer-generated hologram displayed on the spatial light modulator (Hamamatsu, LCOS-SLM X10468-07). In order to make fast neutral flow across the LG beam, a high speed solenoid valve system was installed on the HYPER-I device. Initial results including the comparison of absorption spectra for HG and LG beams will be presented. This study was supported by NINS young scientists collaboration program for cross-disciplinary study, NIFS collaboration research program (NIFS13KOAP026), and JSPS KAKENHI grant number 15K05365.

  9. Laser spectroscopy of gallium isotopes using the ISCOOL RFQ cooler

    CERN Multimedia

    Blaum, K; Kowalska, M; Ware, T; Procter, T J

    2007-01-01

    We propose to study the radioisotopes of gallium (Z=31) by collinear laser spectroscopy using the ISCOOL RFQ ion cooler. The proposed measurements on $^{62-83}$Ga will span both neutron-deficient and neutron-rich isotopes. Of key interest is the suggested development of a proton-skin in the neutron-deficient isotopes. The isotope shifts measured by laser spectroscopy will be uniquely sensitive to this feature. The measurements will also provide a wealth of new information on the gallium nuclear spins, static moments and nuclear charge radii.

  10. Analysis of laser beam propagation effects in atomic laser isotope separation

    International Nuclear Information System (INIS)

    In the atomic laser isotope separation process, the laser beams propagate through the atomic vapor over a long distance. It has been shown that the laser-atom interactions significantly modify the laser pulse shape and propagation velocity, resulting in degradation of the isotope separation efficiency. These propagation effects have been analyzed quantitatively, and a simple scaling formula has been derived to estimate the necessary laser energy for such optically thick atomic vapor. The optimum conditions of incident laser pulse have also been discussed. (author)

  11. Large-angle beam deflection of a laser-cooled sodium beam

    International Nuclear Information System (INIS)

    A sodium atomic beam has been decelerated and laser cooled to a longitudinal beam temperature of less than 30 mK. Subsequently these slow atoms with a typical velocity of 100 m/sec were selectively deflected by laser-light forces. The deflection angle was typically 30 degree. The deflection scheme permits a stabilization of the transverse velocities in the deflected atomic beam down to the quantum-limit temperature for one dimension (0.7x240 μK). The experimentally achieved temperatures are of the order of 1 mK

  12. Time-resolved laser-induced breakdown spectroscopy of aluminum

    Institute of Scientific and Technical Information of China (English)

    LIU Xian-yun; ZHANG Wei-jun; WANG Zhen-ya; HAO Li-qing; HUANG Ming-qiang; ZHAO Wen-wu; LONG Bo; Zhao Wei

    2008-01-01

    We develop a system to measure the elemental composition of unprepared samples using laser-induced breakdown spectroscopy (LIBS) in our laboratory, which can be used for the determination of elements in solids, liquids and aerosols. A description of the instrumentation, including laser, sample chamber and detection, is followed by a brief discussion. The time-resolved LIBS of aluminum at atmospheric pressure is presented. At the end, the possibilities and later uses of this technique are briefly discussed.

  13. Progress in precision laser spectroscopy of p-bar-He

    International Nuclear Information System (INIS)

    The mass of the antiproton (the antiproton-electron mass ratio mp-bar/me) can be deduced from laser spectroscopy measurements of antiprotonic helium, compared to 3-body QED calculations. The most precise spectroscopy measurements have so far been limited by Doppler-broadening at finite temperatures. The status of our ongoing precision measurements is presented, within the framework of the Asacusa experiment at CERN.

  14. The application of magnetic field at low pressure for optimal laser-induced plasma spectroscopy

    International Nuclear Information System (INIS)

    The application of magnetic field in controlling the charged particles of the laser induced plasma is considered. The chara/cteristics of the plasma depend on the electron density and its recombination. The magnetic field effects as well as the ambient pressure are the key factors for determining the electron density of the plasma. Two different laser energies (Low: 30 mJ/pulse, High: 140 mJ/pulse) and the pressure range between 760 Torr and 10 Torr are used when focusing a Nd:YAG laser beam (1064 nm, 6 ns) onto the metal samples where the applied magnetic field varied between 0.1 and 0.5 Tesla. At 760 Torr, the plasma signal enhancement was obtained in the presence of magnetic field when the laser energy was low. With a lowered pressure however, the signal enhancement due to a magnetic field was achieved regardless of the laser energy. The enhancement of the signal in the presence of magnetic field is related to the electron density and the high frequency instability which are controlled by the ambient pressure and magnetic field intensity. In this paper, the optimal conditions for the laser-induced plasma spectroscopy in the magnetic field at various low pressures are discussed. - Highlights: • With magnetic field, LIBS signal enhancement is sensitive to the laser energy • At low pressure, signal enhancement with magnetic field is insensitive to the laser energy • The electron density is analyzed to explain the observed signal intensity variation

  15. A review of the development of portable laser induced breakdown spectroscopy and its applications

    International Nuclear Information System (INIS)

    In this review, we present person-transportable laser induced breakdown spectroscopy (LIBS) devices that have previously been developed and reported in the literature as well as their applications. They are compared with X-ray fluorescent (XRF) devices, which represent their strongest competition. Although LIBS devices have advantages over XRF devices, such as sensitivity to the light elements, high spatial resolution and the possibility to distinguish between different layers of the sample, there are also disadvantages and both are discussed here. Furthermore, the essential portable LIBS instrumentation (laser, spectrograph and detector) is presented, and published results related to new laser sources (diode-pumped solid-state, microchip and fiber lasers) used in LIBS are overviewed. Compared to conventional compact flashlamp pumped solid-state lasers, the new laser sources provide higher repetition rates, higher efficiency (less power consumption) and higher beam quality, resulting in higher fluences, even for lower energies, and could potentially increase the figure of merit of portable LIBS instruments. Compact spectrometers used in portable LIBS devices and their parts (spectrograph, detector) are also discussed. - Highlights: • Overview of portable LIBS devices transportable by a person • Discussion and new trends about portable LIBS instrumentation: laser, spectrograph and detector • Overview of applications of DPSS, microchip and fiber lasers in LIBS

  16. Excimer Laser Beam Analyzer Based on CVD Diamond

    Science.gov (United States)

    Girolami, Marco; Salvatori, Stefano; Conte, Gennaro

    2010-11-01

    1-D and 2-D detector arrays have been realized on CVD-diamond. The relatively high resistivity of diamond in the dark allowed the fabrication of photoconductive "sandwich" strip (1D) or pixel (2D) detectors: a semitransparent light-receiving back-side contact was used for detector biasing. Cross-talk between pixels was limited by using intermediate guard contacts connected at the same ground potential of the pixels. Each pixel photocurrent was conditioned by a read-out electronics composed by a high sensitive integrator and a Σ-Δ ADC converter. The overall 500 μs conversion time allowed a data acquisition rate up to 2 kSPS. The measured fast photoresponse of the samples in the ns time regime suggests to use the proposed devices for fine tuning feedback of high-power pulsed-laser cavities, whereas solar-blindness guarantees high performance in UV beam diagnostics also under high intensity background illumination. Offering unique properties in terms of thermal conductivity and visible-light transparency, diamond represents one of the most suitable candidate for the detection of high-power UV laser emission. The technology of laser beam profiling is evolving with the increase of excimer lasers applications that span from laser-cutting to VLSI and MEMS technologies. Indeed, to improve emission performances, fine tuning of the laser cavity is required. In such a view, the development of a beam-profiler, able to work in real-time between each laser pulse, is mandatory.

  17. Atmospheric Error Correction of the Laser Beam Ranging

    Directory of Open Access Journals (Sweden)

    J. Saydi

    2014-01-01

    Full Text Available Atmospheric models based on surface measurements of pressure, temperature, and relative humidity have been used to increase the laser ranging accuracy by ray tracing. Atmospheric refraction can cause significant errors in laser ranging systems. Through the present research, the atmospheric effects on the laser beam were investigated by using the principles of laser ranging. Atmospheric correction was calculated for 0.532, 1.3, and 10.6 micron wavelengths through the weather conditions of Tehran, Isfahan, and Bushehr in Iran since March 2012 to March 2013. Through the present research the atmospheric correction was computed for meteorological data in base of monthly mean. Of course, the meteorological data were received from meteorological stations in Tehran, Isfahan, and Bushehr. Atmospheric correction was calculated for 11, 100, and 200 kilometers laser beam propagations under 30°, 60°, and 90° rising angles for each propagation. The results of the study showed that in the same months and beam emission angles, the atmospheric correction was most accurate for 10.6 micron wavelength. The laser ranging error was decreased by increasing the laser emission angle. The atmospheric correction with two Marini-Murray and Mendes-Pavlis models for 0.532 nm was compared.

  18. Radiobiological study by using laser-driven proton beams

    Science.gov (United States)

    Yogo, A.; Sato, K.; Nishikino, M.; Mori, M.; Teshima, T.; Numasaki, H.; Murakami, M.; Demizu, Y.; Akagi, S.; Nagayama, S.; Ogura, K.; Sagisaka, A.; Orimo, S.; Nishiuchi, M.; Pirozhkov, A. S.; Ikegami, M.; Tampo, M.; Sakaki, H.; Suzuki, M.; Daito, I.; Oishi, Y.; Sugiyama, H.; Kiriyama, H.; Okada, H.; Kanazawa, S.; Kondo, S.; Shimomura, T.; Nakai, Y.; Tanoue, M.; Sugiyama, H.; Sasao, H.; Wakai, D.; Kawachi, T.; Nishimura, H.; Bolton, P. R.; Daido, H.

    2009-07-01

    Particle acceleration driven by high-intensity laser systems is widely attracting interest as a potential alternative to conventional ion acceleration, including ion accelerator applications to tumor therapy. Recent works have shown that a high intensity laser pulse can produce single proton bunches of a high current and a short pulse duration. This unique feature of laser-ion acceleration can lead to progress in the development of novel ion sources. However, there has been no experimental study of the biological effects of laser-driven ion beams. We describe in this report the first demonstrated irradiation effect of laser-accelerated protons on human lung cancer cells. In-vitro A549 cells are irradiated with a proton dose of 20 Gy, resulting in a distinct formation of γ-H2AX foci as an indicator of DNA double-strand breaks. This is a pioneering result that points to future investigations of the radiobiological effects of laser-driven ion beams. The laser-driven ion beam is apotential excitation source for time-resolved determination of hydroxyl (OH) radical yield, which will explore relationship between the fundamental chemical reactions of radiation effects and consequent biological processes.

  19. Laser beam temporal and spatial tailoring for laser shock processing

    Science.gov (United States)

    Hackel, Lloyd; Dane, C. Brent

    2001-01-01

    Techniques are provided for formatting laser pulse spatial shape and for effectively and efficiently delivering the laser energy to a work surface in the laser shock process. An appropriately formatted pulse helps to eliminate breakdown and generate uniform shocks. The invention uses a high power laser technology capable of meeting the laser requirements for a high throughput process, that is, a laser which can treat many square centimeters of surface area per second. The shock process has a broad range of applications, especially in the aerospace industry, where treating parts to reduce or eliminate corrosion failure is very important. The invention may be used for treating metal components to improve strength and corrosion resistance. The invention has a broad range of applications for parts that are currently shot peened and/or require peening by means other than shot peening. Major applications for the invention are in the automotive and aerospace industries for components such as turbine blades, compressor components, gears, etc.

  20. Intense proton beam source for ITER neutral-beam spectroscopy diagnostics

    International Nuclear Information System (INIS)

    An intense proton beam has been developed to evaluate a gas-cell neutralizer for use in an intense-neutral beam source for Tokomak Spectroscopy diagnostics. The allowed energy range of the proton stream is determined to be 50 to 70 keV from neutralization and reionization cross-sections and from the alpha particle charge exchange recombination intensity as a function of energy (baseline diagnostic). The neutralization evaluation source uses a flashover anode, magnetized, ion-diode. Neutral probes sensitive to energetic atomic and molecular hydrogen, developed to evaluate neutralizer performance, show neutral fluence from the ion-diode during the beam pulse. An array of Rogowski current probes, used to study the evolution of the current path, suggests that expansion of the anode plasma along the radial insulating magnetic field leads to impedance collapse

  1. Laser Welding of Alumina Ceramic Substrates with Two Fixed Beams

    Science.gov (United States)

    Sedore, Blake William Clark

    Laser welding was investigated as a potential joining technology for alumina ceramic substrates. The objective of this study was to develop a method to preheat the ceramic using a single defocused laser beam prior to welding. Engineering ceramics are employed in a variety of systems and environments due to their unique properties. Joining technologies must be developed to facilitate the manufacture of complex or large ceramic components. Laser welding is advantageous as it forms joints rapidly, and does not introduce intermediate materials to form the bond, which can have deleterious effects. The Laser Machining System (LMS) at Queen's University was adapted for this study. A defocused far-infrared (FIR) laser beam was positioned to overlay a focused near-infrared (NIR) laser beam; the defocused FIR beam preheated the ceramic substrate and the focused NIR beam formed the weld. A finite element model was developed in COMSOL MultiPhysics to simulate the preheating processes and to develop a preheating protocol. The protocol was implemented using the FIR beam and adjusted to achieve preheating temperatures of 1450, 1525, and 1600°C. Welds were performed on 1 mm thick alumina plates using the preheating protocols and NIR beam powers of 25, 50, and 75 W. Weld speed was held constant throughout the study at 0.5 mm/s. The preheating protocols were successful at achieving near-constant preheating temperatures, with standard deviations below 32 degrees. Partially penetrating welds were formed with the NIR beam at 25 W, and fully penetrating welds at 50 and 75 W. Large pores were present in the 25 W and 50 W welds. Minimal porosity was observed in the welds formed at 75 W. All of the welded plates experienced a transverse fracture that extended perpendicular to weld, and a longitudinal fracture extending parallel to the weld. This study shows that a fixed defocused laser beam can successfully preheat alumina substrates to the high temperatures required for welding; however

  2. Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

    Science.gov (United States)

    Alejo, A.; Green, A.; Ahmed, H.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; McKenna, P.; Mirfayzi, S. R.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.; Kar, S.

    2016-09-01

    The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher-catcher scenario, anisotropy in neutron emission was studied for the deuterium-deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

  3. Laser coupling of the numerous flattened Gaussian beams in the fiber-based ICF laser driver

    International Nuclear Information System (INIS)

    Highlights: ► The laser coupling issue in the novel fiber-based ICF laser driver is analyzed. ► The requirements for the output capabilities of the fiber laser are given which provides some hint for future research of high energy fiber laser system. -- Abstract: Fiber-based inertial confinement fusion (ICF) laser driver provides a new pathway to realize the inertial fusion energy (IFE). The feasibility of this proposal is checked from the perspective of laser coupling process in this paper. Flattened Gaussian beam (FGB) is assumed for theoretical analysis. The focusing properties of the FGB are used to obtain the requirements for a single laser beam. Based on the typical parameters of the chamber and target in ICF research, the output energy from a single fiber amplification chain is estimated to be over several hundred milli-joule. New fiber structures needs to be designed to meet the requirements

  4. Laser beam propagation effects in atomic laser isotope separation

    International Nuclear Information System (INIS)

    The propagation of two different-color laser pulses in the resonant three-level medium is studied. The three-level Bloch-Maxwell equations are solved numerically to analyze the change of the pulse shapes and the time-varying atomic populations. The pulse delay and the pulse shape break-up are observed especially for the first excitation laser pulse. Complete separation of the two laser pulses occur from a certain critical distance. It is shown that the rapid decrease of the ionization efficiency is caused by the separation of the two laser pulses. (author)

  5. Turbulence-induced persistence in laser beam wandering.

    Science.gov (United States)

    Zunino, Luciano; Gulich, Damián; Funes, Gustavo; Pérez, Darío G

    2015-07-01

    We have experimentally confirmed the presence of long-memory correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. A laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing detrended fluctuation analysis. This is a very well-known and widely used methodology to unveil memory effects from time series. Results obtained from this experimental analysis allow us to confirm that both coordinates behave as highly persistent signals for strong turbulent intensities. This finding is relevant for a better comprehension and modeling of the turbulence effects in free-space optical communication systems and other applications related to propagation of optical signals in the atmosphere. PMID:26125388

  6. Turbulence-induced persistence in laser beam wandering

    CERN Document Server

    Zunino, Luciano; Funes, Gustavo; Pérez, Darío G

    2015-01-01

    We have experimentally confirmed the presence of long-memory correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. A laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing detrended fluctuation analysis. This is a very well-known and widely used methodology to unveil memory effects from time series. Results obtained from this experimental analysis allow us to confirm that both coordinates behave as highly persistent signals for strong turbulent intensities. This finding is relevant for a better comprehension and modeling of the turbulence effects in free-space optical communication systems and other applications related to propagation of optical signals in the atmosphere.

  7. Cutting of nonmetallic materials using Nd:YAG laser beam

    Institute of Scientific and Technical Information of China (English)

    Bashir Ahmed Tahir; Rashid Ahmed; M. G. B. Ashiq; Afaq Ahmed; M. A. Saeed

    2012-01-01

    This study deals with Nd:YAG laser cutting nonmetallic materials,which is one of the most important and popular industrial applications of laser.The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed.For approximate cutting depth,a theoretical study is conducted in terms of material property and cutting speed.Results show a nonlinear relation between the cutting depth and input energy.There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s.An extra energy is utilized in the deep cutting.It is inferred that as the laser power increases,cutting depth increases.The experimental outcomes are in good agreement with theoretical results.This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting,scribing,trimming,engraving,and marking nonmetallic materials.

  8. Cutting of nonmetallic materials using Nd:YAG laser beam

    International Nuclear Information System (INIS)

    This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  9. Hydrodynamics of evaporating aerosols irradiated by intense laser beams

    International Nuclear Information System (INIS)

    An analysis is presented describing the interactions of atmospheric aerosols with a high-intensity laser beam propagating along an atmospheric path. For the case of moderate beam irradiances, diffusive mass transport and conductive energy transport dominate the aerosol-beam interactions. In this regime, the coupled aerosol-beam equations are solved numerically to obtain the spatic-temporal behavior of the propagating beam, and of the irradiated aerosols. For higher beam irradiances, convective transport of mass, energy and momentum away from the irradiated aerosols must be considered. The hydrodynamic equations are solved in the surrounding medium for this regime subject to appropriate ''jump conditions'' at the surface of the irradiated aerosol. Numerical examples illustrative of both regimes are given for the case of irradiated water aerosol droplets. 11 refs., 6 figs

  10. Single-laser, one beam, tetrahedral magneto-optical trap

    CERN Document Server

    Vangeleyn, Matthieu; Riis, Erling; Arnold, Aidan S

    2009-01-01

    We have realised a 4-beam pyramidal magneto-optical trap ideally suited for future microfabrication. Three mirrors split and steer a single incoming beam into a tripod of reflected beams, allowing trapping in the four-beam overlap volume. We discuss the influence of mirror angle on cooling and trapping, finding optimum efficiency in a tetrahedral configuration. We demonstrate the technique using an ex-vacuo mirror system to illustrate the previously inaccessible supra-plane pyramid MOT configuration. Unlike standard pyramidal MOTs both the pyramid apex and its mirror angle are non-critical and our MOT offers improved molasses free from atomic shadows in the laser beams. The MOT scheme naturally extends to a 2-beam refractive version with high optical access. For quantum gas experiments, the mirror system could also be used for a stable 3D tetrahedral optical lattice.

  11. Beam characteristics of CAPEX XUV argon laser

    Czech Academy of Sciences Publication Activity Database

    Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr; Prukner, Václav; Štraus, Jaroslav; Kaufman, J.

    Vol. 8849. San Diego : The Society of Photo-Optical Instrumentation Engineers (SPIE), 2013 - (Klisnick, A.; Menoni, C.), s. 884917-884917 ISBN 978-0-8194-9699-7. ISSN 0277-786X. - (SPIE. 8849). [X-Ray Lasers and Coherent X-Ray Sources: Development and Applications X Conference. San Diego (US), 27.08.2013-29.08.2013] R&D Projects: GA MŠk(CZ) LG13029 Institutional support: RVO:61389021 Keywords : Capillary discharge * XUV laser * laser energy and divergence Subject RIV: BL - Plasma and Gas Discharge Physics

  12. Laser sources for precision spectroscopy on atomic strontium

    OpenAIRE

    Ferrari, G; T.M. Brzozowski; R. DRULLINGER; Poli, N.; Prevedelli, M.; Toninelli, C.; Tino, G. M.

    2004-01-01

    Laser Optics 2003: Solid State Lasers and Nonlinear Frequency Conversion, edited by Vladimir I. Ustugov abstract: We present a new laser setup suited for high precision spectroscopy on atomic strontium. The source is used for an absolute frequency measurement of the visible 5s21S0-5s5p3P1 intercombination line of strontium which is considered a possible candidate for a future optical frequency standard. The optical frequency is measured with an optical comb generator referenced to the SI t...

  13. Mid-IR laser source using hollow waveguide beam combining

    Science.gov (United States)

    Elder, Ian F.; Thorne, Daniel H.; Lamb, Robert A.; Jenkins, R. M.

    2016-03-01

    Hollow waveguide technology is a route to efficient beam combining of multiple laser sources in a compact footprint. It is a technology appropriate for combining free-space or fibre-coupled beams generated by semiconductor, fibre or solidstate laser sources. This paper will present results of a breadboard mid-IR system comprising four laser sources combined using a hollow waveguide optical circuit. In this approach the individual dichroic beam combiner components are held in precision alignment slots in the hollow waveguide circuit and the different input wavelengths are guided between the components to a common output port. The hollow waveguide circuit is formed in the surface of a Macor (machinable glass-ceramic) substrate using precision CNC machining techniques. The hollow waveguides have fundamentally different propagation characteristics to solid core waveguides leading to transmission characteristics close to those of the atmosphere while still providing useful light guidance properties. The transmission efficiency and power handling of the hollow waveguide circuit can be designed to be very high across a broad waveband range. Three of the sources are quantum cascade lasers (QCLs), a semiconductor laser technology providing direct generation of midwave IR output. The combined beams provide 4.2 W of near diffraction-limited output co-boresighted to better than 20 µrad. High coupling efficiency into the waveguides is demonstrated, with negligible waveguide transmission losses. The overall transmission of the hollow waveguide beam combining optical circuit, weighted by the laser power at each wavelength, is 93%. This loss is dominated by the performance of the dichroic optics used to combine the beams.

  14. Effect of hydrogen on beam divergence in copper bromide lasers

    International Nuclear Information System (INIS)

    Full text: The application of copper lasers to precision micro-machining and non-linear frequency conversion into the UV requires high beam quality. In the elemental Copper Vapour Laser (CVL), beam quality and output power can be improved by the addition of hydrogen halides to the flowing neon buffer gas. The sealed Ne-H2-CuBr laser has always been superior to the elemental CVL in terms of beam quality and it is a viable alternative to the latest generation of hydrogen halide CVLs for small scale machining applications by virtue of the efficiency of generating low divergence output. We present our study of variations in the beam quality of these devices with changes in hydrogen pressure. The maximum output power (∼ 14W under these pumping conditions) from this small scale laser oscillator is generated with the addition of 2% hydrogen to the neon buffer gas but the conditions for minimum amplified spontaneous emission (ASE) generation (16% of the total emission) occur with only 0.8% hydrogen. The near field beam profile at 0.8% H2 is near top-hat which minimises the far-field divergence angle and up to 88% of the (non-ASE) laser emission falls within 80μrad divergence (1.3xDL). The gain of the laser appears to be saturated after the initial ASE spike and as a result there is negligible emission during the second round trip of the resonator. The M=62 cavity is then able to reduce the divergence of the initial ASE emission to diffraction limit before the rise in gain of the main laser pulse. Copyright (1999) Australian Optical Society

  15. Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation

    International Nuclear Information System (INIS)

    The lifetime of many spacecrafts are often limited by degradation of their electrical power subsystem, e.g. radiation-damaged solar arrays or failed batteries. Being able to beam power from terrestrial sites using high energy lasers, could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be used for stationkeeping and orbital changes. In addition, extensive research at the Naval Postgraduate School (NPS) has shown the potential for annealing damaged solar cells using lasers. This paper describes that research and a proposed experiment to demonstrate the relevant concepts of high energy laser power beaming to an NPS-built and operated satellite. Preliminary results of ground experiment of laser illuminations of some of the solar panels of one of the spacecrafts are also presented

  16. Effects of laser beam propagation in a multilevel photoionization system

    International Nuclear Information System (INIS)

    When the intense laser pulse propagates in the atomic vapor over a long distance, the laser pulse shape, the carrier frequency and the propagating velocity are greatly modified during the propagation by the resonant and/or the near-resonant interactions with atoms. We have been investigating these effects on the laser beam propagation experimentally and analytically. The simulation code named CEALIS-P has been developed, which employs the coupled three- level Bloch-Maxwell equations to study the atomic excitation and laser beam propagation simultaneously. Several features of the resonant and near-resonant effects based on the the self-induced transparency, the self-phase modulation and the nonlinear group velocity dispersion are described and the influences of such effects on the photoionization efficiency are analyzed.

  17. Beam by design: laser manipulation of electrons in modern accelerators

    CERN Document Server

    Hemsing, Erik; Xiang, Dao; Zholents, Alexander

    2014-01-01

    Accelerator-based light sources such as storage rings and free-electron lasers use relativistic electron beams to produce intense radiation over a wide spectral range for fundamental research in physics, chemistry, materials science, biology and medicine. More than a dozen such sources operate worldwide, and new sources are being built to deliver radiation that meets with the ever increasing sophistication and depth of new research. Even so, conventional accelerator techniques often cannot keep pace with new demands and, thus, new approaches continue to emerge. In this article, we review a variety of recently developed and promising techniques that rely on lasers to manipulate and rearrange the electron distribution in order to tailor the properties of the radiation. Basic theories of electron-laser interactions, techniques to create micro- and nano-structures in electron beams, and techniques to produce radiation with customizable waveforms are reviewed. We overview laser-based techniques for the generation ...

  18. Modulational instability of intense laser beam in magnetized plasma

    International Nuclear Information System (INIS)

    The nonlinear dispersion relation is derived for an intense left-hand elliptically polarized laser beam propagating through magnetized plasma by means of the Lorentz transformation. In terms of the Karpman method, the nonlinear governing equation for the envelope of the laser field is obtained. The modulational instability of the intense left-hand elliptically polarized laser beam in magnetized plasma is analyzed and the temporal growth rate of modulational instability is found. The analysis shows that the maximum growth rate of self-modulation instability is obviously smaller for magnetized plasma compared to the unmagnetized case. It is also shown that the temporal growth rate of modulational instability is increased significantly near the critical surface in a laser-plasma. (authors)

  19. UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC

    International Nuclear Information System (INIS)

    We discuss the design and current status of experiments to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is critical for achieving high quality light sources with high brightness. By using an insertion device such as an undulator and observing changes in the spontaneous emission spectrum, the electron beam energy spread and emittance can be measured with high precision. The initial experiments will use spontaneous emission from 1.5 m of undulator. Later experiments will use up to 5 m of undulator with a goal of a high gain, XUV FEL.

  20. Beam positioning stability analysis on large laser facilities

    Institute of Scientific and Technical Information of China (English)

    Fang; Liu; Zhigang; Liu; Liunian; Zheng; Hongbiao; Huang; Jianqiang; Zhu

    2013-01-01

    Beam positioning stability in a laser-driven inertial confinement fusion(ICF) facility is a vital problem that needs to be fixed. Each laser beam in the facility is transmitted in lots of optics for hundreds of meters, and then targeted in a micro-sized pellet to realize controllable fusion. Any turbulence in the environment in such long-distance propagation would affect the displacement of optics and further result in beam focusing and positioning errors. This study concluded that the errors on each of the optics contributed to the target, and it presents an efficient method of enhancing the beam stability by eliminating errors on error-sensitive optics. Optimizations of the optical system and mechanical supporting structures are also presented.

  1. Formation of optical vortices using coherent laser beam arrays

    CERN Document Server

    Wang, Li-Gang; Zhu, Shi-Yao

    2008-01-01

    We present a novel proposal to generate an optical vortex beam by using the coherent-superposition of multi-beams in a radial symmetrical configuration. In terms of the generalized Huygens-Fresnel diffraction integral, we have derived the general propagation expression for the coherent radial laser arrays. Based on the derived formulae, we have analyzed the effects of the beamlet number, the separation distance of the beamlets and the topological charge on the intensity and phase distributions of the resulted beams. Our simulation results show that optical vortices could be efficiently formed and generated due to the interference and superposition effect of all the beamlets, during the propagation process of the coherent radial laser arrays with the initial well-organized phase distributions through the free space. In the focusing system, the resulted beam near the focusing plane has the strong rotation effect with the phase helicity.

  2. Two-dimensional fluorescence spectroscopy of laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; LaHaye, Nicole L.; Phillips, Mark C.

    2016-08-01

    We use a two-dimensional laser-induced fluorescence spectroscopy technique to measure the coupled absorption and emission properties of atomic species in plasmas produced via laser ablation of solid aluminum targets at atmospheric pressure. Emission spectra from the Al I 394.4 nm and Al I 396.15 nm transitions are measured while a frequency-doubled, continuous-wave, Ti:Sapphire laser is tuned across the Al I 396.15 nm transition. The resulting two-dimensional spectra show the energy coupling between the two transitions via increased emission intensity for both transitions during resonant absorption of the continuous-wave laser at one transition. Time-delayed and gated detection of the emission spectrum is used to isolate the resonantly-excited fluorescence emission from the thermally-excited emission from the plasma. In addition, the tunable continuous-wave laser measures the absorption spectrum of the Al transition with ultra-high resolution after the plasma has cooled, resulting in narrower spectral linewidths than observed in emission spectra. Our results highlight that fluorescence spectroscopy employing continuous-wave laser re-excitation after pulsed laser ablation combines benefits of both traditional emission and absorption spectroscopic methods.

  3. An approach of open-path gas sensor based on tunable diode laser absorption spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hui Xia; Wenqing Liu; Yujun Zhang; Ruifeng Kan; Min Wang; Ying He; Yiben Cui; Jun Ruan; Hui Geng

    2008-01-01

    Tunable diode laser absorption spectroscopy (TDLAS) is a new method to detect trace-gas qualitatively or quantificationally based on the scan characteristic of the diode laser to obtain the absorption spectroscopy in the characteristic absorption region. A time-sharing scanning open-path TDLAS system using two near infrared distributed feedback (DFB) tunable diode lasers is designed to detect CH4 and H2S in leakage of natural gas. A low-cost Fresnel lens is used in this system as receiving optics which receives the laser beam reflected by a solid corner cube reflector with a distance of up to about 60 m. High sensitivity is achieved by means of wavelength-modulation spectroscopy with second-harmonic detection. The minimum detection limits of 1.1 ppm·m for CH4 and 15 ppm·m for H2S are demonstrated with a total optical path of 120 m. The simulation monitoring experiment of nature gas leakage was carried out with this system. According to the receiving light efficiency of optical system and detectable minimum light intensity of detection, the detectable optical path of the system can achieve 1 - 2 km. The sensor is suitable for natural gas leakage monitoring application.

  4. Detection of early caries by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji

    2015-07-01

    To improve sensitivity of dental caries detection by laser-induced breakdown spectroscopy (LIBS) analysis, it is proposed to utilize emission peaks in the ultraviolet. We newly focused on zinc whose emission peaks exist in ultraviolet because zinc exists at high concentration in the outer layer of enamel. It was shown that by using ratios between heights of an emission peak of Zn and that of Ca, the detection sensitivity and stability are largely improved. It was also shown that early caries are differentiated from healthy part by properly setting a threshold in the detected ratios. The proposed caries detection system can be applied to dental laser systems such as ones based on Er:YAG-lasers. When ablating early caries part by laser light, the system notices the dentist that the ablation of caries part is finished. We also show the intensity of emission peaks of zinc decreased with ablation with Er:YAG laser light.

  5. Laser beam deflection in nonlinearly steepened flow profiles

    International Nuclear Information System (INIS)

    A simple model is presented for laser beam deflection by nonlinear induced profile changes near the sonic point in an expanding plasma. The deflection angle scales as a weak power of the laser intensity, since the flow is resonantly perturbed. A significant deflection can occur even in the absence of filamentation which, however, can further enhance the deflection angle. Improved calculations of filamentation in flowing plasmas require consideration of these self-consistent modifications of the zeroth-order state, which can act to stabilize the instability. LASNEX calculations are used to illustrate the self-consistent profile changes and beam deflection. (Author)

  6. Nonparaxial optical vortices and Kummer laser beams

    Science.gov (United States)

    Kovalev, Alexey A.; Kotlyar, Victor V.; Nalimov, Anton G.

    2013-09-01

    Two approaches to describe nonparaxial optical vortices were considered. One approach is to use a revised Kirchhoff integral, which does not neglect the relief of an optical element. Using this integral and the finite-difference time-domain method it is shown that an optical vortex generated by a refractive spiral plate with a relief step has an asymmetric profile. The annular diffraction pattern in the vortex beam cross-section is found to be disturbed not only for the near-field diffraction but also for the middle-field diffraction, at a distance of several Fresnel lengths. Another approach is to solve the Helmholtz equation without any approximations. An analytical solution to describe propagation of a light beam in the positive direction of the optical axis was found. The complex amplitude of such a beam is found to be in direct proportion to the product of two linearly independent solutions of Kummer's differential equation. Relationships for a particular case of such beams-namely, the Hankel-Bessel (HB) beams-are deduced. The autofocusing of the HB beams is studied.

  7. High energy photon production in strong colliding laser beams

    OpenAIRE

    Kuchiev, Michael; Ingham, Julian

    2015-01-01

    The collision of two intense, low-frequency laser beams is considered. The $e^-e^+$ pairs created in this field are shown to exhibit recollisions, which take place at high energy accumulated due to the wiggling of fermions. The resulting $e^-e^+$ annihilation produces high energy photons, or heavy particles. The coherent nature of the laser field provides strong enhancement of the probability of these events. Analytical and numerical results are outlined.

  8. Modelling of the laser beam propagation in the Silva project

    International Nuclear Information System (INIS)

    The full text of publication follows. The AVLIS process is a general process for converting a feed stream into a product stream in which a selected set of isotopes has been enriched or depleted by a laser beam. At CEA (French atomic energy commission), the process has been applied to the enrichment of uranium for light water nuclear reactor fuel and designed as the SILVA Project. This process is based on the selective multistep photoionization of the uranium vapour stream. The uranium vapor is produced by an electron bombardment and expands upwards in vacuum. Tunable laser frequencies are generated in a dye laser system that is pumped by copper vapor lasers. The laser light illuminates the atomic vapor near the surface of an ion extractor. Ions of the resonant isotope (235) are then extracted and separated from neutrals (mainly composed of 238 isotope). For modelling a large scale situation, it is necessary to take into account the propagation of laser beams into a vapor composed of two isotopes: 238U (99,3%) and 235U (0,7%). This laser beam propagation takes place over a kilometer range in these conditions. The presence of the non resonant isotope (238 isotope) can induce some important change in the characteristics of the laser beam during the propagation. Spatial, temporal, and spectral effects are expected and can be observed. The resolution of Schroedinger and Maxwell equations with classical explicit numerical schemes leads to a prohibitive calculation time. An original code (PRODIGE) with optimized numerical schemes and parallelization technique has been developed in order to describe accurately the SILVA situation. This code is able to perform a propagation calculation over a kilometer range with a 60 h calculation time and 256 processors on the TERA computer. (authors)

  9. Theory of microdroplet and microbubble deformation by Gaussian laser beam

    OpenAIRE

    Ellingsen, Simen Å.

    2012-01-01

    The theory for linear deformations of fluid microparticles in a laser beam of Gaussian profile is presented, when the beam focus is at the particle center as in optical trapping. Three different fluid systems are considered: water microdroplet in air, air microbubble in water, and a special oil-emulsion in water system used in experiments with optical deformation of fluid interfaces. We compare interface deformations of the three systems when illuminated by a wide (compared to particle radius...

  10. Materials processing with tightly focused femtosecond vortex laser beams

    OpenAIRE

    Hnatovsky, Cyril; Shvedov, Vladlen G.; Krolikowski, Wieslaw; Rode, Andrei V.

    2010-01-01

    This letter is the first demonstration of material modification using tightly focused femtosecond laser vortex beams. Double-charge femtosecond vortices were synthesized with the polarization-singularity beam converter described in Ref [1] and then focused using moderate and high numerical aperture optics (viz., NA = 0.45 and 0.9) to ablate fused silica and soda-lime glasses. By controlling the pulse energy we consistently machine high-quality micron-size ring-shaped structures with less than...

  11. Instability Versus Equilibrium Propagation of Laser Beam in Plasma

    OpenAIRE

    Lushnikov, Pavel M.; Rose, Harvey A.

    2003-01-01

    We obtain, for the first time, an analytic theory of the forward stimulated Brillouin scattering instability of a spatially and temporally incoherent laser beam, that controls the transition between statistical equilibrium and non-equilibrium (unstable) self-focusing regimes of beam propagation. The stability boundary may be used as a comprehensive guide for inertial confinement fusion designs. Well into the stable regime, an analytic expression for the angular diffusion coefficient is obtain...

  12. A beam guide system for laser-surgery

    International Nuclear Information System (INIS)

    A beam guide system for medical application is described. Using rotatable dielectric mirrors the transmission of the system is very high and the beam quality is not debased. A special end tube suitable for surgery in the nasal cavity is presented solving the problems of a clean optical end face. The instrument was applied clinically to surgery of the lower human turbinates using an argon ion laser with a power up to 4 W. (Author)

  13. Formation of optical vortices using coherent laser beam arrays

    OpenAIRE

    Wang, Li-Gang; Wang, Li-Qin; Zhu, Shi-Yao

    2008-01-01

    We present a novel proposal to generate an optical vortex beam by using the coherent-superposition of multi-beams in a radial symmetrical configuration. In terms of the generalized Huygens-Fresnel diffraction integral, we have derived the general propagation expression for the coherent radial laser arrays. Based on the derived formulae, we have analyzed the effects of the beamlet number, the separation distance of the beamlets and the topological charge on the intensity and phase distribution...

  14. Improving sensitivity of laser-induced breakdown spectroscopy using laser plasmas interaction

    Science.gov (United States)

    Il'in, Alexey A.; Golik, Sergey S.; Nagorny, Ivan G.; Bulanov, Alexey V.

    2006-11-01

    Laser plasmas interaction and spectral characteristics of plasma were investigated at a laser breakdown in a normal atmosphere with the purpose of improving laser-induced breakdown spectroscopy sensitivity. Colliding plasmas interaction was investigated depending on mechanism of absorption wave of laser radiation and distance between foci. Laser supported detonation wave, breakdown wave and fast wave of ionization are absorption wave observed in experiment. It was shown that seed electrons for cascade breakdown in front of fast wave of ionization is occurred due to oxygen molecules photoionization. Molecular emission and collapse of intensity of plasma continuum during the initial moments of laser plasma expansion were registered. The line/continuum ratio was essentially increased in case of laser plasmas interaction. Thus laser plasmas interaction improves sensitivity of LIBS.

  15. Converter of laser beams with circular polarization to cylindrical vector beams based on anisotropic crystals

    Science.gov (United States)

    Paranin, Vyacheslav D.; Karpeev, Sergey V.; Kazanskiy, Nikolay L.; Krasnov, Andrey P.

    2016-03-01

    The optical system for converting laser beams with circular polarization to cylindrical vector beams on the basis of anisotropic crystals has been developed. The experimental research of beam formation quality has been carried out on the both polarization and structural characteristics. The research showed differences in the formation of the azimuthal and radial polarizations for Gaussian modes and Bessel beams. The boundaries of changes of the optical system parameters to form different types of polarizations with different amplitude and phase distributions have been identified.

  16. Coherent laser spectroscopy of anti pHe+

    International Nuclear Information System (INIS)

    The facilities of the coherent laser pulse spectroscopy of the anti pHe+ transitions are considered taking the magnetic structure of the energy levels into account. The possibility for the observation of the dynamics of ''intramolecular'' motions is also analyzed. (orig.)

  17. Laser photothermal spectroscopy of light-induced absorption

    Energy Technology Data Exchange (ETDEWEB)

    Skvortsov, L A [Institute of Cryptography, Communications and Informatics, Moscow (Russian Federation)

    2013-01-31

    Basic methods of laser photothermal spectroscopy, which are used to study photoinduced absorption in various media, are briefly considered. Comparative analysis of these methods is performed and the latest results obtained in this field are discussed. Different schemes and examples of their practical implementation are considered. (review)

  18. Molecular oxygen detection using frequency modulation diode laser spectroscopy

    Science.gov (United States)

    Wang, Liang-Guo; Sachse, Glen

    1990-01-01

    A high-sensitivity spectroscopic measurement of O2 using two-tone frequency modulation spectroscopy with a GaAlAs diode laser is presented. An oxygen sensor based on this technique would be non-intrusive, compact and possess high sensitivity and fast time response.

  19. Laser-Induced Breakdown Spectroscopy and Chlorophyll a Flourescence Transients

    DEFF Research Database (Denmark)

    Frydenvang, Jens

    trustworthy results of a sufficient quality; something that remains a problem for many in-situ methods. In my PhD, I present my work with two such in-situ methods, Laser-Induced Breakdown Spectroscopy (LIBS) and OJIP transients, the rising part of chlorophyll a fluorescence transients from dark-adapted leaves....

  20. Scintillation reduction for laser beams propagating through turbulent atmosphere

    International Nuclear Information System (INIS)

    We numerically examine the spatial evolution of the structure of coherent and partially coherent laser beams, including the optical vortices, propagating in turbulent atmospheres. The influence of beam fragmentation and wandering relative to the axis of propagation (z-axis) on the value of the scintillation index (SI) of the signal at the detector is analysed. These studies were performed for different dimensions of the detector, distances of propagation, and strengths of the atmospheric turbulence. Methods for significantly reducing the SI are described. These methods utilize averaging of the signal at the detector over a set of partially coherent beams (PCBs). It is demonstrated that the most effective approach is using a set of PCBs with definite initial directions of propagation relative to the z-axis. This approach results in a significant compensation of the beam wandering which in many cases is the main contributor to the SI. A novel method is to generate the PCBs by combining two laser beams-Gaussian and vortex beams, with different frequencies (the difference between these two frequencies being significantly smaller than the frequencies themselves). In this case, the effective suppression of the SI does not require high-frequency modulators. This result is important for achieving gigabit data rates in long-distance laser communication through turbulent atmospheres.

  1. Performance improvements in temperature reconstructions of 2-D tunable diode laser absorption spectroscopy (TDLAS)

    Science.gov (United States)

    Choi, Doo-Won; Jeon, Min-Gyu; Cho, Gyeong-Rae; Kamimoto, Takahiro; Deguchi, Yoshihiro; Doh, Deog-Hee

    2016-02-01

    Performance improvement was attained in data reconstructions of 2-dimensional tunable diode laser absorption spectroscopy (TDLAS). Multiplicative Algebraic Reconstruction Technique (MART) algorithm was adopted for data reconstruction. The data obtained in an experiment for the measurement of temperature and concentration fields of gas flows were used. The measurement theory is based upon the Beer-Lambert law, and the measurement system consists of a tunable laser, collimators, detectors, and an analyzer. Methane was used as a fuel for combustion with air in the Bunsen-type burner. The data used for the reconstruction are from the optical signals of 8-laser beams passed on a cross-section of the methane flame. The performances of MART algorithm in data reconstruction were validated and compared with those obtained by Algebraic Reconstruction Technique (ART) algorithm.

  2. The effect of laser beam size in a zig-zag collimator on transverse cooling of a krypton atomic beam

    Indian Academy of Sciences (India)

    Vivek Singh; V B Tiwari; S Singh; S R Mishra; H S Rawat

    2014-07-01

    The effect of size of a cooling laser beam in a zig-zag atomic beam collimator on transverse cooling of a krypton atomic beam is investigated. The simulation results show that discreteness in the interaction between the cooling laser beam and atomic beam, arising due to finite size and incidence angle of the cooling laser beam, significantly reduces the value of transverse velocity capture range of the collimator. The experimental observations show the trend similar to that obtained from simulations. Our study can be particularly useful where a small zig-zag collimator is required.

  3. Laser induced breakdown spectroscopy stratigraphic characterization of multilayered painted surfaces

    International Nuclear Information System (INIS)

    Laser spectroscopy techniques are modern and competitive methods for elemental analysis. Laser induced breakdown spectroscopy (LIBS), due to its advantages as minimally invasive method that provides real time monitoring and selectivity, is a suitable tool to analyze sample composition. Based on the known emission spectra of heavy metals such as Pb, Zn, Au, Ca, a stratigraphic study regarding the identification of the painting layers content of different mock-up samples was performed. LIBS was used to monitor the laser induced stepwise selective removal of the painting layers and to analyze their composition. The obtained LIBS spectra were correlated with profilometric measurements. - Highlights: ► LIBS was used to analyze heavy metals in mock-up painting samples. ► LIBS data are correlated with profilometric and optical microscopy measurements. ► Appropriate analysis parameters are provided for some materials used in painting.

  4. Optimization of laser-induced breakdown spectroscopy for coal powder analysis with different particle flow diameters

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shunchun, E-mail: epscyao@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); State Key Laboratory of Pulsed Power Laser Technology, Electronic Engineering Institute, Hefei 230037 (China); Xu, Jialong; Dong, Xuan; Zhang, Bo; Zheng, Jianping [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China)

    2015-08-01

    The on-line measurement of coal is extremely useful for emission control and combustion process optimization in coal-fired plant. Laser-induced breakdown spectroscopy was employed to directly analyze coal particle flow. A set of tapered tubes were proposed for beam-focusing the coal particle flow to different diameters. For optimizing the measurement of coal particle flow, the characteristics of laser-induced plasma, including optical breakdown, the relative standard deviation of repeated measurement, partial breakdown spectra ratio and line intensity, were carefully analyzed. The comparison of the plasma characteristics among coal particle flow with different diameters showed that air breakdown and the random change in plasma position relative to the collection optics could significantly influence on the line intensity and the reproducibility of measurement. It is demonstrated that the tapered tube with a diameter of 5.5 mm was particularly useful to enrich the coal particles in laser focus spot as well as to reduce the influence of air breakdown and random changes of plasma in the experiment. - Highlights: • Tapered tube was designed for beam-focusing the coal particle flow as well as enriching the particles in laser focus spot. • The characteristics of laser-induced plasma of coal particle flow were investigated carefully. • An appropriate diameter of coal particle flow was proven to benefit for improving the performance of LIBS measurement.

  5. Optimization of laser-induced breakdown spectroscopy for coal powder analysis with different particle flow diameters

    International Nuclear Information System (INIS)

    The on-line measurement of coal is extremely useful for emission control and combustion process optimization in coal-fired plant. Laser-induced breakdown spectroscopy was employed to directly analyze coal particle flow. A set of tapered tubes were proposed for beam-focusing the coal particle flow to different diameters. For optimizing the measurement of coal particle flow, the characteristics of laser-induced plasma, including optical breakdown, the relative standard deviation of repeated measurement, partial breakdown spectra ratio and line intensity, were carefully analyzed. The comparison of the plasma characteristics among coal particle flow with different diameters showed that air breakdown and the random change in plasma position relative to the collection optics could significantly influence on the line intensity and the reproducibility of measurement. It is demonstrated that the tapered tube with a diameter of 5.5 mm was particularly useful to enrich the coal particles in laser focus spot as well as to reduce the influence of air breakdown and random changes of plasma in the experiment. - Highlights: • Tapered tube was designed for beam-focusing the coal particle flow as well as enriching the particles in laser focus spot. • The characteristics of laser-induced plasma of coal particle flow were investigated carefully. • An appropriate diameter of coal particle flow was proven to benefit for improving the performance of LIBS measurement

  6. Absorption spectroscopy of laser excited europium vapour

    International Nuclear Information System (INIS)

    Absorption spectra of europium vapour irradiated by intense, monochromatic resonance radiation at the wavelengths of the three principal resonance lines, 4f76s2, 8S(J=7/2)→4f76s6p, y 8P(J=5/2, 7/2 and 9/2) at 466.2, 462.7 and 459.4 nm respectively, have been photographed at high resolution. Pulsed resonance radiation was obtained from a tunable, narrow-band dye laser pumped by a nitrogen laser: a broad-band dye laser pumped by the same nitrogen laser provided background radiation. Our spectra covered the ranges 380-400 nm, and 410-450 nm, each one showing transitions from a single resonance level to upper levels in the region of either the 4f76s, 7S or the 4f76s, 9S ionization limit of EuII. In the shorter wavelength range the spectra consisted of weak autoionized series converging towards the 7S limit. In the longer wavelength range the three spectra were surprisingly dissimilar. The majority of the upper levels could be arranged into five highly-perturbed series, one corresponding to each of the J values 3/2, 5/2, 7/2, 9/2 and 11/2. These series arose from excitation of the 6p electron to high lying d-orbitals. The absorption transitions to the series members are only prominent in regions where the series are strongly perturbed, indicating that most of the line strength is derived from the perturbing levels. Possible origins for the perturbing levels are discussed. Little evidence was found for a series arising from excitation of the 6p electron to high lying s-orbitals. (author)

  7. Visible spectroscopy of laser produced plasma

    International Nuclear Information System (INIS)

    In the frame of work of these studies of material hardening using intense shock wave produced during laser material interaction, the knowledge of thermal coupling requires determination of plasma characteristics. Optical emission spectra (3800-7100 Angstrom ) of 10, 6 μ m TEA pulsed CO2 laser produced plasma on aluminum and carbon targets have been studied. CO2 laser radiation intensities of 108-109 W/cm2 lasting for about 1.6 to 8 μ s induced plasma formation on aluminum and carbon targets situated in vacuum chamber (10- 5 Torr). Spatial and temporal evolution of emission spectra are obtained with a map of different plasma states. Absorption lines, continuum and emission lines were found to predominate successively the spectrum as the target approaches. Two diagnosis systems have been employed: a gated (1 to 10 μs ) image intensified Optical Multichannel analyzer (OMA EGG Model 1460) and two photomultipliers (PM) set to discriminate the plasma lines from the continuum radiation. Moreover, studies have been conducted on high speed interferometry yielding a time resolved map of plasma electron densities. These measurements were made using an IMACON 790 counter camera (104-2.107 frame/s) together with streak photographies of 1ns/mm to 1 μ s/mm. In some cases the authors were able to evaluate plasma temperature from the relative emission intensity ratio of ion states of a same element

  8. Accelerator beams for x-ray-gamma lasers

    International Nuclear Information System (INIS)

    The relativistic accelerator beams interaction with strong laser fields in different schemes for generation of intense shortwave coherent radiation is investigated. As a new generation of light sources of shortwave radiation, specifically for x-ray and γ-ray lasers, the high brightness ion beams or channelled in the crystals ultrarelativistic electron beams are considered where due to the existence of quantum bound states the ion-photon or channelled electron-photon interaction cross sections are resonantly enhanced by several orders with respect to the Thompson/Compton cross section on the free electrons. The latter means that the coherent radiation generated in such systems will rather exceed by intensity the contemporary Free Electron Laser systems. Hence, the stimulated radiation by relativistic charged particle beams with discrete energy levels is of certain interest as a potential synthesis of the conventional Quantum Generators and Free Electron Lasers in x-ray and γ-ray domains. Besides, the spectral intensity of spontaneous radiation of the channelled electrons/ ions well exceeds the intensities of other radiation processes in this frequency range. Hence, the Self-Amplified Spontaneous Emission (SASE) regimes of x-ray laser by means of relativistic ion beam or channelled in a crystal ultrarelativistic electron beam with the strong counterprop-agating pump laser fields are investigated. The consideration is based on the self-consistent set of the Maxwell and relativistic quantum kinetic equations. In the considering schemes the pump wave (optical or strong infrared laser radiation) due to the Doppler up-shifting of its frequency resonantly couples two internal ionic or transverse electronic levels in the channel of a crystal, and the necessity of the initial inverse population of energy levels for lasing in such systems vanishes, which is obligatory for conventional quantum generators on atomic systems. Different regimes of generation of coherent x

  9. A new in-gas-laser ionization and spectroscopy laboratory for off-line studies at KU Leuven

    Science.gov (United States)

    Kudryavtsev, Yu.; Creemers, P.; Ferrer, R.; Granados, C.; Gaffney, L. P.; Huyse, M.; Mogilevskiy, E.; Raeder, S.; Sels, S.; Van den Bergh, P.; Van Duppen, P.; Zadvornaya, A.

    2016-06-01

    The in-gas laser ionization and spectroscopy (IGLIS) technique is used to produce and to investigate short-lived radioactive isotopes at on-line ion beam facilities. In this technique, the nuclear reaction products recoiling out of a thin target are thermalized and neutralized in a high-pressure noble gas, resonantly ionized by the laser beams in a two-step process, and then extracted from the ion source to be finally accelerated and mass separated. Resonant ionization of radioactive species in the supersonic gas jet ensures very high spectral resolution because of essential reduction of broadening mechanisms. To obtain the maximum efficiency and the best spectral resolution, properties of the supersonic jet and the laser beams must be optimized. To perform these studies a new off-line IGLIS laboratory, including a new high-repetition-rate laser system and a dedicated off-line mass separator, has been commissioned. In this article, the specifications of the different components necessary to achieve optimum conditions in laser-spectroscopy studies of radioactive beams using IGLIS are discussed and the results of simulations are presented.

  10. Laser-Accelerated Proton Beams as a New Particle Source

    OpenAIRE

    Nürnberg, Frank

    2010-01-01

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. Today's high power, ultrashort pulse laser systems are capable of achieving laser intensities up to 10^21 W/cm^2. When focused onto thin foil targets, extremely high field gradients of the order of TV/m are produced on the rear side of the target resulting in the acceleration of protons to multi-MeV energies with an exponential spectrum including up to 10^13 particles. This a...

  11. Instability Versus Equilibrium Propagation of Laser Beam in Plasma

    CERN Document Server

    Lushnikov, P M; Lushnikov, Pavel M.; Rose, Harvey A.

    2003-01-01

    We obtain, for the first time, an analytic theory of the forward stimulated Brillouin scattering instability of a spatially and temporally incoherent laser beam, that controls the transition between statistical equilibrium and non-equilibrium (unstable) self-focusing regimes of beam propagation. The stability boundary may be used as a comprehensive guide for inertial confinement fusion designs. Well into the stable regime, an analytic expression for the angular diffusion coefficient is obtained, which provides an essential correction to a geometric optic approximation for beam propagation.

  12. Characterization of Laser Beam Shaping Optics Based on Their Ablation Geometry of Thin Films

    OpenAIRE

    Stefan Rung; Johannes Barth; Ralf Hellmann

    2014-01-01

    Thin film ablation with pulsed nanosecond lasers can benefit from the use of beam shaping optics to transform the Gaussian beam profile with a circular footprint into a Top-Hat beam profile with a rectangular footprint. In general, the quality of the transformed beam profile depends strongly on the beam alignment of the entire laser system. In particular, the adjustment of the beam shaping element is of upmost importance. For an appropriate alignment of the beam shaper, it is generally necess...

  13. Laser-Bioplasma Interaction: The Blood Type Transmutation Induced by Multiple Ultrashort Wavelength Laser Beams

    Science.gov (United States)

    Stefan, V. Alexander

    2015-11-01

    The interaction of ultrashort wavelength multi laser beams with the flowing blood thin films leads to the transmutation of the blood types A, B, and AB into O type. This is a novel mechanism of importance for the transfusion medicine. Laser radiation is in resonance with the eigen-frequency modes of the antigen proteins and forces the proteins to parametrically oscillate until they get kicked out from the surface. The stripping away of antigens is done by the scanning-multiple-lasers of a high repetition rate in the blue-purple frequency domain. The guiding-lasers are in the red-green frequency domain. The laser force, (parametric interaction with the antigen eigen-oscillation), upon the antigen protein molecule must exceed its weight. The scanning laser beam is partially reflected as long as the antigen(s) is not eliminated. The process of the protein detachment can last a few minutes. Supported by Nikola Tesla Labs., Stefan University.

  14. Laser-driven proton beams: Acceleration mechanism, beam optimization, and radiographic applications

    Energy Technology Data Exchange (ETDEWEB)

    Borghesi, M.; Romagnani, L.; Kar, S.; Wilson, P.A. [School of Mathematics and Physics, The Queen' s University of Belfast (United Kingdom); Cecchetti, C.A. [School of Mathematics and Physics, The Queen' s University of Belfast (United Kingdom); Also with the Intense Laser Irradiation Laboratory, IPCF-CNR, Pisa (Italy); Toncian, T.; Pipahl, A.; Amin, M.; Jung, R.; Osterholz, J.; Willi, O. [Institute for Laser and Plasma Physics, Heinrich Heine University, Dusseldorf (Germany); Fuchs, J.; Audebert, P.; Brambrink, E. [Laboratoire pour l' Utilisation des Lasers Intenses LULI, UMR 7605 CNRS-CEA-Ecole Polytechnique, 91 - Palaiseau (France); Antici, P. [Laboratoire pour l' Utilisation des Lasers Intenses LULI, UMR 7605 CNRS CEA Ecole Polytechnique, 91 - Palaiseau (France); Frascati National Laboratories INFN, Frascati (Italy); Nazarov, W. [School of Chemistry, University of St. Andrews, St. Andrews (United Kingdom); Clarke, R.J.; Notley, M.; Neely, D. [Central Laser Facility, STFC Rutherford Appleton Laboratory, OX Didcot (United Kingdom); Mora, P.; Grismayer, T. [Centre de Physique Theorique, Ecole Polytechnique, CNRS, 91 - Palaiseau (France); Schurtz, G. [Centre d' Etudes des Lasers Intenses et Applications, UMR 5107 University Bordeaux I-CNRS-CEA, 33 - Talence (France); Schiavi, A. [Dipartimento di Energetica, Universita -La Sapienza-, Rome (Italy); Sentoku, Y.; D' Humieres, E. [Physics Department, MS 220, University of Nevada, Reno, NV (United States)

    2008-08-15

    This paper reviews recent experimental activity in the area of optimization, control, and application of laser-accelerated proton beams, carried out at the Rutherford Appleton Laboratory and the Laboratoire pour l'Utilisation des Lasers Intenses 100 TW facility in France. In particular, experiments have investigated the role of the scale length at the rear of the plasma in reducing target-normal-sheath-acceleration acceleration efficiency. Results match with recent theoretical predictions and provide information in view of the feasibility of proton fast-ignition applications. Experiments aiming to control the divergence of the proton beams have investigated the use of a laser-triggered micro-lens, which employs laser-driven transient electric fields in cylindrical geometry, enabling to focus the emitted protons and select monochromatic beamlets; out of the broad spectrum beam. This approach could be advantageous in view of a variety of applications. The use of laser-driven protons as a particle probe for transient field detection has been developed and applied to a number of experimental conditions. Recent work in this area has focused on the detection of large-scale self-generated magnetic fields in laser-produced plasmas and the investigation of fields associated to the propagation of relativistic electron both on the surface and in the bulk of targets irradiated by high-power laser pulses. (authors)

  15. Dynamics and transport of laser-accelerated particle beams

    International Nuclear Information System (INIS)

    The subject of this thesis is the investigation and optimization of beam transport elements in the context of the steadily growing field of laser-driven particle acceleration. The first topic is the examination of the free vacuum expansion of an electron beam at high current density. It could be shown that particle tracking codes which are commonly used for the calculation of space charge effects will generate substantial artifacts in the regime considered here. The artifacts occurring hitherto predominantly involve insufficient prerequisites for the Lorentz transformation, the application of inadequate initial conditions and non negligible retardation artifacts. A part of this thesis is dedicated to the development of a calculation approach which uses a more adequate ansatz calculating space charge effects for laser-accelerated electron beams. It can also be used to validate further approaches for the calculation of space charge effects. The next elements considered are miniature magnetic quadrupole devices for the focusing of charged particle beams. General problems involved with their miniaturization concern distorting higher order field components. If these distorting components cannot be controlled, the field of applications is very limited. In this thesis a new method for the characterization and compensation of the distorting components was developed, which might become a standard method when assembling these permanent magnet multipole devices. The newly developed characterization method has been validated at the Mainz Microtron (MAMI) electron accelerator. Now that we can ensure optimum performance, the first application of permanent magnet quadrupole devices in conjunction with laser-accelerated ion beams is presented. The experiment was carried out at the Z-Petawatt laser system at Sandia National Laboratories. A promising application for laser-accelerated electron beams is the FEL in a university-scale size. The first discussion of all relevant aspects

  16. Dynamics and transport of laser-accelerated particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Stefan

    2010-04-19

    The subject of this thesis is the investigation and optimization of beam transport elements in the context of the steadily growing field of laser-driven particle acceleration. The first topic is the examination of the free vacuum expansion of an electron beam at high current density. It could be shown that particle tracking codes which are commonly used for the calculation of space charge effects will generate substantial artifacts in the regime considered here. The artifacts occurring hitherto predominantly involve insufficient prerequisites for the Lorentz transformation, the application of inadequate initial conditions and non negligible retardation artifacts. A part of this thesis is dedicated to the development of a calculation approach which uses a more adequate ansatz calculating space charge effects for laser-accelerated electron beams. It can also be used to validate further approaches for the calculation of space charge effects. The next elements considered are miniature magnetic quadrupole devices for the focusing of charged particle beams. General problems involved with their miniaturization concern distorting higher order field components. If these distorting components cannot be controlled, the field of applications is very limited. In this thesis a new method for the characterization and compensation of the distorting components was developed, which might become a standard method when assembling these permanent magnet multipole devices. The newly developed characterization method has been validated at the Mainz Microtron (MAMI) electron accelerator. Now that we can ensure optimum performance, the first application of permanent magnet quadrupole devices in conjunction with laser-accelerated ion beams is presented. The experiment was carried out at the Z-Petawatt laser system at Sandia National Laboratories. A promising application for laser-accelerated electron beams is the FEL in a university-scale size. The first discussion of all relevant aspects

  17. Laser Plasmas : Effect of rippled laser beam on excitation of ion acoustic wave

    Indian Academy of Sciences (India)

    Nareshpal Singh Saini; Tarsem Singh Gill

    2000-11-01

    Growth of a radially symmetrical ripple, superimposed on a Gaussian laser beam in collisional unmagnetised plasma is investigated. From numerical computation, it is observed that self-focusing of main beam as well as ripple determine the growth dynamics of ripple with the distance of propagation. The effect of growing ripple on excitation of ion acoustic wave (IAW) has also been studied

  18. Laser-driven generation of ultra-intense proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Badziak, J.; Jablonski, S.; Kubkowska, M.; Parys, P.; Rosinski, M.; Wolowski, J. [EURATOM, Inst Plasma Phys and Laser Microfus, PL-00908 Warsaw (Poland); Antici, P.; Fuchs, J.; Mancic, A. [UPMC, LULI, Ecole Polytech, CNRS, CEA, F-91128 Palaiseau (France); Szydlowski, A. [Andrzej Soltan Inst Nucl Studies, Otwock (Poland)

    2010-07-01

    The results of experimental and numerical studies of high-intensity proton beam generation driven by a short laser pulse of relativistic intensity are reported. In the experiment, a 350 fs laser pulse of 1.06 or 0.53 m wavelength and intensity up to 2*10{sup 19} Wcm{sup -2} irradiated a thin (0.6-2{mu}m) plastic (PS) or Au/PS (plastic covered by 0.2{mu}m Au front layer) target along the target normal. The effect of laser intensity, the target structure and the laser wavelength on the proton beam parameters and laser-protons energy conversion efficiency were examined. Both the measurements and one-dimensional particle-in-cell simulations showed that MeV proton beams of intensity 10{sup 18}Wcm{sup -2} and current density 10{sup 12}Acm{sup -2} at the source can be produced when the laser intensity-wavelength squared product I{sub L{lambda}}{sup 2} is 10{sup 19}Wcm{sup -2}m{sup 2} and the laser-target interaction conditions approach the skin-layer ponderomotive acceleration (SLPA) requirements. The simulations also proved that at I{sub L{lambda}}{sup 2} {>=} 5*10{sup 19}Wcm{sup -2}m{sup 2} and {lambda} {<=} 0.53{mu}m, SLPA clearly prevails over other acceleration mechanisms and it can produce multi-MeV proton beams of extremely high intensities above 10{sup 20}Wcm{sup -2}. (authors)

  19. Advanced instrumentation in laser spectroscopy: from ultras to extremes

    International Nuclear Information System (INIS)

    The advent of laser in early sixties of the last century has generated tremendous impetus in the field of fundamental research, which includes branches like optical, atomic, molecular and nuclear physics etc. In effect the age old field of optics is resurrected through this new development. The instrumentation related to laser based diagnostic system has become an inseparable part of many ultra-precision devices like atomic clock, magnetometer etc. Also it has found its application in giant experimental facilities e.g. diagnostic systems associated with accelerator. In this talk I will emphasize on two important applications of laser based instrumentation: (i) precision time and frequency standard and (ii) spectroscopy of exotic nuclei. The first one will include basic outline of laser-atom interaction in coherent media and its manifestation in developing a precision time standard device i.e. a portable atomic clock, based on Electromagnetically Induced Transparency. The later part of the talk will focus on the important application of laser in exotic nuclear spectroscopy. Here I will mainly discuss a prospective programme on setting up a laser spectrometer in conjunction with an Isotope Separator On Line (ISOL). (author)

  20. Terahertz plasmonic laser radiating in an ultra-narrow beam

    CERN Document Server

    Wu, Chongzhao; Reno, John L; Kumar, Sushil

    2016-01-01

    Plasmonic lasers (spasers) generate coherent surface-plasmon-polaritons (SPPs) and could be realized at subwavelength dimensions in metallic cavities for applications in nanoscale optics. Plasmonic cavities are also utilized for terahertz quantum-cascade lasers (QCLs), which are the brightest available solid-state sources of terahertz radiation. A long standing challenge for spasers is their poor coupling to the far-field radiation. Unlike conventional lasers that could produce directional beams, spasers have highly divergent radiation patterns due to their subwavelength apertures. Here, we theoretically and experimentally demonstrate a new technique for implementing distributed-feedback (DFB) that is distinct from any other previously utilized DFB schemes for semiconductor lasers. The so-termed antenna-feedback scheme leads to single-mode operation in plasmonic lasers, couples the resonant SPP mode to a highly directional far-field radiation pattern, and integrates hybrid SPPs in surrounding medium into the ...

  1. Nanoscale focused ion beam from laser-cooled lithium atoms

    International Nuclear Information System (INIS)

    We demonstrate a new type of nanoscale focused ion beam (FIB) based on photoionizing laser-cooled atoms held at millikelvin temperatures in a magneto-optical trap (MOT). This new source expands the range of available ionic species and accessible ion beam energies for FIBs, enhancing their role as one of the most important tools for nanoscale characterization and fabrication. We show examples of microscopy with lithium ions obtained by scanning the FIB and collecting the resulting secondary electrons, and characterize the beam focus by a 25-75% rise distance measurement of (26.7 ± 1.0) nm at a beam energy of 2 keV. We also examine the dependence of the focal size on MOT temperature and beam energy. (paper)

  2. Optimization of laser accelerated proton beams for possible applications

    International Nuclear Information System (INIS)

    Optimization of transported proton beams through a pulsed solenoid in the laser proton experiment LIGHT at GSI has been studied numerically. TraceWin, SRIM and ATIMA codes were employed for this study with an initial distribution generated by MATLAB program fitted to Phelix measured data. Two individual tools have been used to produce protons beam as a later beam source: an aperture located at the solenoid focal spot as energy selection tool; and a scattering foil at a suitable position in the beam path that smoothens the simulated radial energy imprint on the beam profile. The simulation results show that the proton energy spectrum is filtered by the aperture and the radial energy correlation is smoothened.

  3. Metal surface temperature induced by moving laser beams

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Meijer, J.

    1995-01-01

    Whenever a metal is irradiated with a laser beam, electromagnetic energy is transformed into heat in a thin surface layer. The maximum surface temperature is the most important quantity which determines the processing result. Expressions for this maximum temperature are provided by the literature fo

  4. Image Processing In Laser-Beam-Steering Subsystem

    Science.gov (United States)

    Lesh, James R.; Ansari, Homayoon; Chen, Chien-Chung; Russell, Donald W.

    1996-01-01

    Conceptual design of image-processing circuitry developed for proposed tracking apparatus described in "Beam-Steering Subsystem For Laser Communication" (NPO-19069). In proposed system, desired frame rate achieved by "windowed" readout scheme in which only pixels containing and surrounding two spots read out and others skipped without being read. Image data processed rapidly and efficiently to achieve high frequency response.

  5. Beam cooling by using laser-undulator beat wave

    International Nuclear Information System (INIS)

    Non-Hamiltonian manipulation of internal structure of phase space of charged particle beams can result in much faster cooling than the conventional stochastic cooling. The longitudinal emittance reduction is accomplished by the ponderomotive force of the beat between the undulator and the laser adjusted appropriate in its broadband spectrum through feedback at each turn. (author)

  6. Atomic Beam Laser Spectrometer for In-field Isotopic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Alonso [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Actinide Analytical Chemistry Group

    2016-06-22

    This is a powerpoint presentation for the DTRA quarterly program review that goes into detail about the atomic beam laser spectrometer for in-field isotopic analysis. The project goals are the following: analysis of post-detonation debris, determination of U and Pu isotopic composition, and fieldable prototype: < 2ft3, < 1000W.

  7. A Laser Lock System using Multiple Overlapping Beams

    Science.gov (United States)

    Harper, Stuart; Francis, Ben; Erickson, Christopher; Durfee, Dallin

    2010-10-01

    We describe a system wherein the lock of trapping, ionizing, and ion resonance lasers for a Sr experiment are bootstrapped together in a single neutral atom vapor cell. This is done by overlapping beams to optically pump the atoms into the necessary states.

  8. Potential Sources of Gravitational Wave Emission and Laser Beam Interferometers

    OpenAIRE

    Pacheco, J. A. de Freitas

    2000-01-01

    The properties of potential gravitational wave sources like neutron stars, black holes and binary systems are reviewed, as well as the different contributions (stochastic and continuous) to the gravitational wave background. The detectability of these sources by the present generation of laser beam interferometers, which will be fully operational around 2002, is also considered.

  9. Two-photon flow cytometer with laser scanning Bessel beams

    Science.gov (United States)

    Wang, Yongdong; Ding, Yu; Ray, Supriyo; Paez, Aurelio; Xiao, Chuan; Li, Chunqiang

    2016-03-01

    Flow cytometry is an important technique in biomedical discovery for cell counting, cell sorting and biomarker detection. In vivo flow cytometers, based on one-photon or two-photon excited fluorescence, have been developed for more than a decade. One drawback of laser beam scanning two-photon flow cytometer is that the two-photon excitation volume is fairly small due to the short Rayleigh range of a focused Gaussian beam. Hence, the sampling volume is much smaller than one-photon flow cytometry, which makes it challenging to count or detect rare circulating cells in vivo. Bessel beams have narrow intensity profiles with an effective spot size (FWHM) as small as several wavelengths, making them comparable to Gaussian beams. More significantly, the theoretical depth of field (propagation distance without diffraction) can be infinite, making it an ideal solution as a light source for scanning beam flow cytometry. The trade-off of using Bessel beams rather than a Gaussian beam is the fact that Bessel beams have small concentric side rings that contribute to background noise. Two-photon excitation can reduce this noise, as the excitation efficiency is proportional to intensity squared. Therefore, we developed a two-photon flow cytometer using scanned Bessel beams to form a light sheet that intersects the micro fluidic channel.

  10. ROBUST POSITIONING OF LASER BEAMS USING PROPORTIONAL INTEGRAL DERIVATIVE AND BASED OBSERVER-FEEDBACK CONTROL

    OpenAIRE

    Kwabena A. Konadu; Sun Yi; Wonchang Choi; Taher Abu-Lebdeh

    2013-01-01

    High-precision positioning of laser beams has been a great challenge in industry due to inevitable existence of noise and disturbance. The work presented in this study addresses this problem by employing two different control strategies: Proportional Integral Derivative (PID) control and state feedback control with an observer. The control strategies are intended to stabilize the position of a laser beam on a Position Sensing Device (PSD) located on a Laser Beam Stabilization (or, laser beam ...

  11. Frequency-Comb based laser spectroscopy of Halo Nuclei: The nuclear charge radius of 11Be

    International Nuclear Information System (INIS)

    Nuclear charge radii of halo isotopes provide a direct proof of the halo structure of neutron rich isotopes. If they are compared to the matter radii from nuclear reactions, a geometrical picture of the two- and three body structures can be extracted. We have determined the nuclear charge radii of 7,9,10,11Be by high-precision laser spectroscopy [1,2] and combination with accurate calculations of the mass-dependent isotope shifts [3,4]. The on-line measurements were performed with collinear laser spectroscopy in the 2s1/2 → 2p1/2 transition on a beam of Be+ ions. Collinear and anti collinear laser beams were used simultaneously and absolute frequency determination was applied using a frequency comb. This yielded an accuracy in the isotope-shift measurements of about 1 MHz. The charge radius of the beryllium was found to decrease from 7Be to 10Be and then increases for the halo nucleus 11Be. We compare our results with predictions of ah initio nuclear structure calculations and the conclusions about the geometric size of the halo will be discussed.(author)

  12. Aplanatic beam shaping for diffraction limited beam circularization of tapered laser diodes

    Science.gov (United States)

    Heinrich, Arne; Hagen, Clemens; Harlander, Maximilian; Nussbaumer, Bernhard

    2014-03-01

    Many laser applications require a circular, astigmatism-free, diffraction limited, high power beam. A tapered laser diode can generate up to 6 W output power in a diffraction limited beam. However the beam is elliptical and highly astigmatic rendering the design of beam shaping challenging. We present a diffraction limited beam shaping design, especially suitable to circularize and collimate highly astigmatic beams. The setup consists of a simple plano-convex cylindrical lens in the aplanatic condition and an asphere. The first lens matches the divergence of the fast- to the slow axis at the point where the beam is circular while the following asphere collimates the beam. The aplanatic condition is fulfilled by choosing a glass with a specific refractive index depending on the ratio between fast- and slow axis divergence. This cylindrical lens introduces neither spherical error nor primary coma, which makes it insensitive to misalignment. The setup has been tested with a high power laser diode at 980 nm with a 6 mm long taper (angle 6°) and a facet width of 425 μm. The optics have a transmission of about 90% and the resulting beam has a M2 < 1.5. As a proof of principle 3.2 W were coupled into a 15 μm (NA 0.06) LMA fiber with 55% efficiency corresponding to a brightness B = 140 MW/(cm2 sr). Furthermore the presented beam shaping can easily be extended to bars or multiple emitters to reach power levels that are to date only achievable with complex wavelength combination techniques.

  13. Design and Status of the ELIMED Beam Line for Laser-Driven Ion Beams

    Directory of Open Access Journals (Sweden)

    G. A. Pablo Cirrone

    2015-08-01

    Full Text Available Charged particle acceleration using ultra-intense and ultra-short laser pulses has gathered a strong interest in the scientific community and it is now one of the most attractive topics in the relativistic laser-plasma interaction research. Indeed, it could represent the future of particle acceleration and open new scenarios in multidisciplinary fields, in particular, medical applications. One of the biggest challenges consists of using, in a future perspective, high intensity laser-target interaction to generate high-energy ions for therapeutic purposes, eventually replacing the old paradigm of acceleration, characterized by huge and complex machines. The peculiarities of laser-driven beams led to develop new strategies and advanced techniques for transport, diagnostics and dosimetry of the accelerated particles, due to the wide energy spread, the angular divergence and the extremely intense pulses. In this framework, the realization of the ELIMED (ELI-Beamlines MEDical applications beamline, developed by INFN-LNS (Catania, Italy and installed in 2017 as a part of the ELIMAIA beamline at the ELI-Beamlines (Extreme Light Infrastructure Beamlines facility in Prague, has the aim to investigate the feasibility of using laser-driven ion beams in multidisciplinary applications. ELIMED will represent the first user’s open transport beam line where a controlled laser-driven ion beam will be used for multidisciplinary and medical studies. In this paper, an overview of the beamline, with a detailed description of the main transport elements, will be presented. Moreover, a description of the detectors dedicated to diagnostics and dosimetry will be reported, with some preliminary results obtained both with accelerator-driven and laser-driven beams.

  14. Numerical analysis of the beam quality and spectrum of wavelength-beam-combined laser diode arrays

    Science.gov (United States)

    Tang, Xuan; Wang, Xiao-Jun; Ke, Wei-Wei

    2015-02-01

    In this paper, a numerical model is presented to simulation the performance of the wavelength-beam-combined laser diode arrays (LDA) system. The eigen mode expansion method is used to describe the two-dimensional optical amplification and the strength of field feedback of external cavity. To describe the mode competition in laser diodes, the gain saturation effect is considered. The two-dimension distributions of the carrier concentration, recombination rates, and optical gain are calculated for solving the laser dynamic equation. The Fresnel integration, grating equation and mode overlap integration are used to obtain the feedback coefficient of extent cavity diffraction. Quantum noise is considered to evaluate the spectral linewidth of semiconductor laser. Based on the numerical model, the impact of the mutual optical feedback on the beam quality and spectrum of the LDA is present and analysis.

  15. An online, energy-resolving beam profile detector for laser-driven proton beams.

    Science.gov (United States)

    Metzkes, J; Zeil, K; Kraft, S D; Karsch, L; Sobiella, M; Rehwald, M; Obst, L; Schlenvoigt, H-P; Schramm, U

    2016-08-01

    In this paper, a scintillator-based online beam profile detector for the characterization of laser-driven proton beams is presented. Using a pixelated matrix with varying absorber thicknesses, the proton beam is spatially resolved in two dimensions and simultaneously energy-resolved. A thin plastic scintillator placed behind the absorber and read out by a CCD camera is used as the active detector material. The spatial detector resolution reaches down to ∼4 mm and the detector can resolve proton beam profiles for up to 9 proton threshold energies. With these detector design parameters, the spatial characteristics of the proton distribution and its cut-off energy can be analyzed online and on-shot under vacuum conditions. The paper discusses the detector design, its characterization and calibration at a conventional proton source, as well as the first detector application at a laser-driven proton source. PMID:27587116

  16. Pixel diamond detectors for excimer laser beam diagnostics

    Science.gov (United States)

    Girolami, M.; Allegrini, P.; Conte, G.; Salvatori, S.

    2011-05-01

    Laser beam profiling technology in the UV spectrum of light is evolving with the increase of excimer lasers and lamps applications, that span from lithography for VLSI circuits to eye surgery. The development of a beam-profiler, able to capture the excimer laser single pulse and process the acquired pixel current signals in the time period between each pulse, is mandatory for such applications. 1D and 2D array detectors have been realized on polycrystalline CVD diamond specimens. The fast diamond photoresponse, in the ns time regime, suggests the suitability of such devices for fine tuning feedback of high-power pulsed-laser cavities, whereas solar-blindness guarantees high performance in UV beam diagnostics, also under high intensity background illumination. Offering unique properties in terms of thermal conductivity and visible-light transparency, diamond represents one of the most suitable candidate for the detection of high-power UV laser emission. The relatively high resistivity of diamond in the dark has allowed the fabrication of photoconductive vertical pixel-detectors. A semitransparent light-receiving back-side contact has been used for detector biasing. Each pixel signal has been conditioned by a multi-channel read-out electronics made up of a high-sensitive integrator and a Σ-Δ A/D converter. The 500 μs conversion time has allowed a data acquisition rate up to 2 kSPS (Sample Per Second).

  17. Laser-induced breakdown spectroscopy for in-cylinder equivalence ratio measurements in laser-ignited natural gas engines.

    Science.gov (United States)

    Joshi, Sachin; Olsen, Daniel B; Dumitrescu, Cosmin; Puzinauskas, Paulius V; Yalin, Azer P

    2009-05-01

    In this contribution we present the first demonstration of simultaneous use of laser sparks for engine ignition and laser-induced breakdown spectroscopy (LIBS) measurements of in-cylinder equivalence ratios. A 1064 nm neodynium yttrium aluminum garnet (Nd:YAG) laser beam is used with an optical spark plug to ignite a single cylinder natural gas engine. The optical emission from the combustion initiating laser spark is collected through the optical spark plug and cycle-by-cycle spectra are analyzed for H(alpha)(656 nm), O(777 nm), and N(742 nm, 744 nm, and 746 nm) neutral atomic lines. The line area ratios of H(alpha)/O(777), H(alpha)/N(746), and H(alpha)/N(tot) (where N(tot) is the sum of areas of the aforementioned N lines) are correlated with equivalence ratios measured by a wide band universal exhaust gas oxygen (UEGO) sensor. Experiments are performed for input laser energy levels of 21 mJ and 26 mJ, compression ratios of 9 and 11, and equivalence ratios between 0.6 and 0.95. The results show a linear correlation (R(2) > 0.99) of line intensity ratio with equivalence ratio, thereby suggesting an engine diagnostic method for cylinder resolved equivalence ratio measurements. PMID:19470212

  18. Gamma-ray generation using laser-accelerated electron beam

    Science.gov (United States)

    Park, Seong Hee; Lee, Ho-Hyung; Lee, Kitae; Cha, Yong-Ho; Lee, Ji-Young; Kim, Kyung-Nam; Jeong, Young Uk

    2011-06-01

    A compact gamma-ray source using laser-accelerated electron beam is being under development at KAERI for nuclear applications, such as, radiography, nuclear activation, photonuclear reaction, and so on. One of two different schemes, Bremsstrahlung radiation and Compton backscattering, may be selected depending on the required specification of photons and/or the energy of electron beams. Compton backscattered gamma-ray source is tunable and quasimonochromatic and requires electron beams with its energy of higher than 100 MeV to produced MeV photons. Bremsstrahlung radiation can generate high energy photons with 20 - 30 MeV electron beams, but its spectrum is continuous. As we know, laser accelerators are good for compact size due to localized shielding at the expense of low average flux, while linear RF accelerators are good for high average flux. We present the design issues for a compact gamma-ray source at KAERI, via either Bremsstrahlung radiation or Compton backscattering, using laser accelerated electron beams for the potential nuclear applications.

  19. Characterization of laser - induced plasmas by atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Pace, Diego M; Bertuccelli, Graciela; D' Angelo, Cristian A, E-mail: ddiaz@exa.unicen.edu.ar, E-mail: gbertucc@exa.unicen.edu.ar, E-mail: cdangelo@exa.unicen.edu.ar [Instituto de Fisica ' Arroyo Seco' , Facultad de Ciencias Exactas, U.N.C.P.B.A., Campus Universitario, Paraje Arroyo Seco, (B7000GHG) Tandil, Buenos Aires (Argentina)

    2011-01-01

    In this work, Laser-induced breakdown spectroscopy (LIBS) has been applied to characterization of plasmas generated in air at atmospheric pressure from a calcium hydroxide sample with a known concentration of Mg by using an infrared Nd:YAG laser. The influence of laser irradiance on plasma morphology and emission intensity was studied. Spatially-integrated intensities of Mg I-II lines along the line-of-sight were measured for different laser energies and delay times. The plasma temperature and the electron density were determined in each case by using and algorithm that calculates the optical thickness of the spectral lines and reproduces their experimental profiles in a framework of an homogeneous plasma in LTE that takes into account the effects of self-absorption. The results obtained showed the usefulness of this approach to provide additional information retrieved from the optical thickness of spectral lines for plasma characterization in LIBS experiments.

  20. Laser beam-profile impression and target thickness impact on laser-accelerated protons

    International Nuclear Information System (INIS)

    Experimental results on the influence of the laser focal spot shape onto the beam profile of laser-accelerated protons from gold foils are reported. The targets' microgrooved rear side, together with a stack of radiochromic films, allowed us to deduce the energy-dependent proton source-shape and size, respectively. The experiments show, that shape and size of the proton source depend only weakly on target thickness as well as shape of the laser focus, although they strongly influence the proton's intensity distribution. It was shown that the laser creates an electron beam that closely follows the laser beam topology, which is maintained during the propagation through the target. Protons are then accelerated from the rear side with an electron created electric field of a similar shape. Simulations with the Sheath-Accelerated Beam Ray-tracing for IoN Analysis code SABRINA, which calculates the proton distribution in the detector for a given laser-beam profile, show that the electron distribution during the transport through a thick target (50 μm Au) is only modified due to multiple small angle scattering. Thin targets (10 μm) show large source sizes of over 100 μm diameter for 5 MeV protons, which cannot be explained by multiple scattering only and are most likely the result of refluxing electrons