Sample records for sub-nanometer racetrack laser

  1. Sub-nanometer drift correction for super-resolution imaging. (United States)

    Tang, Y; Wang, X; Zhang, X; Li, J; Dai, L


    Spatial resolution of conventional far-field fluorescence microscopy is limited by diffraction of light. Single-molecule localization microscopy (SMLM), such as (direct) stochastic optical reconstruction microscopy (dSTORM/STORM), and (fluorescence) photoactivation localization microscopy (fPALM/PALM), can break this barrier by localizing single emitters and reconstructing super-resolution image with much higher precision. Nevertheless, a SMLM measurement needs to record a large number of image frames and takes considerable recording time. In this process, sample drift becomes a critical problem and cannot be neglected. In this Letter, we present a sub-nanometer precision, low-cost sample drift correction method based on minimizing normalized root-mean-square error (NRMSE) between bright field images. Two optical configurations are suggested for recording bright field and fluorescence images simultaneously or alternately. The method was demonstrated on simulated data, and better than 0.3 nm drift correction precision was achieved. It was also applied on dSTORM imaging of F-actins of 3T3 cell, and the quality of reconstructed super-resolution image was improved observably. This method does not require special hardware, extra labelling or markers, and no precision decline due to photobleaching. It can be applied as an add-on for SMLM setups and achieves sub-nanometer precision drift correction for post-measurement or real time drift compensation.

  2. Complex biomembrane mimetics on the sub-nanometer scale. (United States)

    Heberle, Frederick A; Pabst, Georg


    Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain-forming lipid mixtures to asymmetric lipid bilayers. Here, we review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. In particular, we focus on: (1) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function of a size transition from nanoscopic to macroscopic domains; (2) membrane-mediated protein partitioning into lipid domains; (3) the role of the aqueous medium in tuning interactions between membranes and domains; and (4) leaflet-specific structure in asymmetric bilayers and passive lipid flip-flop.

  3. Sub-nanometer resolution XPS depth profiling: Sensing of atoms

    Energy Technology Data Exchange (ETDEWEB)

    Szklarczyk, Marek, E-mail: [Faculty of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw (Poland); Shim-Pol, ul. Lubomirskiego 5, 05-080 Izabelin (Poland); Macak, Karol; Roberts, Adam J. [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom); Takahashi, Kazuhiro [Kratos XPS Section, Shimadzu Corp., 380-1 Horiyamashita, Hadano, Kanagawa 259-1304 (Japan); Hutton, Simon [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom); Głaszczka, Rafał [Shim-Pol, ul. Lubomirskiego 5, 05-080 Izabelin (Poland); Blomfield, Christopher [Kratos Analytical Ltd, Wharfside, Trafford Wharf Road, Manchester, M17 1GP (United Kingdom)


    Highlights: • Angle resolved photoelectron depth profiling of nano thin films. • Sensing atomic position in SAM films. • Detection of direction position of adsorbed molecules. - Abstract: The development of a method capable of distinguishing a single atom in a single molecule is important in many fields. The results reported herein demonstrate sub-nanometer resolution for angularly resolved X-ray photoelectron spectroscopy (ARXPS). This is made possible by the incorporation of a Maximum Entropy Method (MEM) model, which utilize density corrected electronic emission factors to the X-ray photoelectron spectroscopy (XPS) experimental results. In this paper we report on the comparison between experimental ARXPS results and reconstructed for both inorganic and organic thin film samples. Unexpected deviations between experimental data and calculated points are explained by the inaccuracy of the constants and standards used for the calculation, e.g. emission factors, scattering intensity and atomic density through the studied thickness. The positions of iron, nitrogen and fluorine atoms were determined in the molecules of the studied self-assembled monolayers. It has been shown that reconstruction of real spectroscopic data with 0.2 nm resolution is possible.

  4. Sub-nanometer resolution XPS depth profiling: Sensing of atoms (United States)

    Szklarczyk, Marek; Macak, Karol; Roberts, Adam J.; Takahashi, Kazuhiro; Hutton, Simon; Głaszczka, Rafał; Blomfield, Christopher


    The development of a method capable of distinguishing a single atom in a single molecule is important in many fields. The results reported herein demonstrate sub-nanometer resolution for angularly resolved X-ray photoelectron spectroscopy (ARXPS). This is made possible by the incorporation of a Maximum Entropy Method (MEM) model, which utilize density corrected electronic emission factors to the X-ray photoelectron spectroscopy (XPS) experimental results. In this paper we report on the comparison between experimental ARXPS results and reconstructed for both inorganic and organic thin film samples. Unexpected deviations between experimental data and calculated points are explained by the inaccuracy of the constants and standards used for the calculation, e.g. emission factors, scattering intensity and atomic density through the studied thickness. The positions of iron, nitrogen and fluorine atoms were determined in the molecules of the studied self-assembled monolayers. It has been shown that reconstruction of real spectroscopic data with 0.2 nm resolution is possible.

  5. Sub-Nanometer Channels Embedded in Two-Dimensional Materials

    KAUST Repository

    Han, Yimo


    Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically-thin p-n junctions2-7, metal-semiconductor contacts8-10, and metal-insulator barriers11-13 have been demonstrated. While 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions are also necessary. Although external one-dimensional (1D) carbon nanotubes14 can be used to locally gate 2D materials, this adds a non-trivial third dimension, complicating device integration and flexibility. Here, we report the direct synthesis of sub-nanometer 1D MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalyzed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Molecular dynamics (MD) simulations have identified other combinations of 2D materials that could form 1D channels. Density function theory (DFT) calculation predicts these 1D channels display type II band alignment needed for carrier confinement and charge separation to access the ultimate length scales necessary for future electronic applications.

  6. Insight into Ion Transfer through the Sub-Nanometer Channels in Zeolitic Imidazolate Frameworks. (United States)

    Jiang, Ze-Yu; Liu, Hai-Ling; Ahmed, Saud Asif; Hanif, Sumaira; Ren, Shi-Bin; Xu, Jing-Juan; Chen, Hong-Yuan; Xia, Xing-Hua; Wang, Kang


    A crack-free sub-nanometer composite structure for the study of ion transfer was constructed by in situ growth of ZIF-90 [Zn(ICA)2 , ICA=Imidazole-2-carboxaldehyde] on the tip of a glass nanopipette. The potential-driven ion transfer through the sub-nanometer channels in ZIF-90 is strongly influenced by the pH of the solution. A rectification ratio over 500 is observed in 1 m KCl solution under alkaline conditions (pH 11.58), which is the highest value reported under such a high salt concentration. Fluorescence experiments show the super-high rectification ratio under alkaline conditions results from the strong electrostatic interaction between ions and the sub-nanometer channels of ZIF-90. In addition to providing a general pathway for further study of mass-transfer process through sub-nanometer channels, the approach enable all kinds of metal-organic frameworks (MOFs) to be used as ionic permselectivity materials in nanopore-based analysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. SI-traceable absolute distance measurement over more than 800 meters with sub-nanometer interferometry by two-color inline refractivity compensation (United States)

    Meiners-Hagen, Karl; Meyer, Tobias; Mildner, Jutta; Pollinger, Florian


    In this work, we demonstrate two-color inline refractivity compensation in a heterodyne synthetic wavelength interferometer for a measurement of absolute distances over several hundred meters with sub-millimeter accuracy. Two frequency-doubled Nd:YAG lasers with a coherence length of more than 1 km are used as light sources. Direct SI traceability is achieved by controlling the lasers' frequency difference in the radio frequency regime. The resulting synthetic wavelengths at 532 nm and 1064 nm are used for the absolute distance measurement and dispersion-based inline refractive index compensation. A standard deviation of 50 μm is achieved for distances up to 864 m. This performance corresponds to a standard deviation of the observable, the difference of the four optical wavelengths, on a sub-nanometer level. Comparison against white light interferometry confirms sub-millimeter accuracy over this distance. Temporally resolved data over 864 m provide quantitative insights into the influence of chromatic beam paths.

  8. Figuring large optics at the sub-nanometer level: compensation for coating and gravity distortions. (United States)

    Gensemer, Stephen; Gross, Mark


    Large, precision optics can now be manufactured with surface figures specified at the sub-nanometer level. However, coatings and gravity deform large optics, and there are limits to what can be corrected by clever compensation. Instead, deformations caused by stress from optical mounts and deposited coatings must be incorporated into the optical design. We demonstrate compensation of coating stress on a 370mm substrate to λ/200 by a process of coating and annealing. We also model the same process and identify the leading effects that must be anticipated in fabrication of optics for future gravitational wave detectors and other applications of large, precisely figured optics, and identify the limitations inherent in using coatings to compensate for these deformations.

  9. Bimetallic Ag-Pt Sub-nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Negreiros, Fabio R. [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Halder, Avik [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Yin, Chunrong [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Singh, Akansha [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Barcaro, Giovanni [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Sementa, Luca [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Tyo, Eric C. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Bartling, Stephan [Institut für Physik, Universität Rostock, Rostock Germany; Meiwes-Broer, Karl-Heinz [Institut für Physik, Universität Rostock, Rostock Germany; Seifert, Sönke [X-ray Science Division, Argonne National Laboratory, Lemont IL USA; Sen, Prasenjit [Harish-Chandra Research Institute, HBNI, Chhatnag Road Jhunsi Allahabad 211019 India; Nigam, Sandeep [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai- 400 085 India; Fukui, Nobuyuki [East Tokyo Laboratory, Genesis Research Institute, Inc., Ichikawa Chiba 272-0001 Japan; Yasumatsu, Hisato [Cluster Research Laboratory, Toyota Technological Institute: in, East Tokyo Laboratory, Genesis Research Institute, Inc. Ichikawa, Chiba 272-0001 Japan; Vajda, Stefan [Materials Science Division, Argonne National Laboratory, Lemont IL USA; Nanoscience and Technology Division, Argonne National Laboratory, Lemont IL USA; Institute for Molecular Engineering, University of Chicago, Chicago IL USA; Fortunelli, Alessandro [CNR-ICCOM & IPCF, Consiglio Nazionale delle Ricerche, Pisa Italy; Materials and Process Simulation Center, California Institute of Technology, Pasadena CA USA


    A combined experimental and theoretical investigation of Ag-Pt sub-nanometer clusters as heterogeneous catalysts in the CO -> CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size-selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first-principles simulations at realistic coverage. Insitu GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano-aggregates, in which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O-2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species.

  10. Helium Ion Microscopy (HIM) for the imaging of biological samples at sub-nanometer resolution (United States)

    Joens, Matthew S.; Huynh, Chuong; Kasuboski, James M.; Ferranti, David; Sigal, Yury J.; Zeitvogel, Fabian; Obst, Martin; Burkhardt, Claus J.; Curran, Kevin P.; Chalasani, Sreekanth H.; Stern, Lewis A.; Goetze, Bernhard; Fitzpatrick, James A. J.


    Scanning Electron Microscopy (SEM) has long been the standard in imaging the sub-micrometer surface ultrastructure of both hard and soft materials. In the case of biological samples, it has provided great insights into their physical architecture. However, three of the fundamental challenges in the SEM imaging of soft materials are that of limited imaging resolution at high magnification, charging caused by the insulating properties of most biological samples and the loss of subtle surface features by heavy metal coating. These challenges have recently been overcome with the development of the Helium Ion Microscope (HIM), which boasts advances in charge reduction, minimized sample damage, high surface contrast without the need for metal coating, increased depth of field, and 5 angstrom imaging resolution. We demonstrate the advantages of HIM for imaging biological surfaces as well as compare and contrast the effects of sample preparation techniques and their consequences on sub-nanometer ultrastructure. PMID:24343236

  11. Sub-nanometer dimensions control of core/shell nanoparticles prepared by atomic layer deposition. (United States)

    Weber, M J; Verheijen, M A; Bol, A A; Kessels, W M M


    Bimetallic core/shell nanoparticles (NPs) are the subject of intense research due to their unique electronic, optical and catalytic properties. Accurate and independent control over the dimensions of both core and shell would allow for unprecedented catalytic performance. Here, we demonstrate that both core and shell dimensions of Pd/Pt core/shell nanoparticles (NPs) supported on Al2O3 substrates can be controlled at the sub-nanometer level by using a novel strategy based on atomic layer deposition (ALD). From the results it is derived that the main conditions for accurate dimension control of these core/shell NPs are: (i) a difference in surface energy between the deposited core metal and the substrate to obtain island growth; (ii) a process yielding linear growth of the NP cores with ALD cycles to obtain monodispersed NPs with a narrow size distribution; (iii) a selective ALD process for the shell metal yielding a linearly increasing thickness to obtain controllable shell growth exclusively on the cores. For Pd/Pt core/shell NPs it is found that a minimum core diameter of 1 nm exists above which the NP cores are able to catalytically dissociate the precursor molecules for shell growth. In addition, initial studies on the stability of these core/shell NPs have been carried out, and it has been demonstrated that core/shell NPs can be deposited by ALD on high aspect ratio substrates such as nanowire arrays. These achievements show therefore that ALD has significant potential for the preparation of tuneable heterogeneous catalyst systems.

  12. Mechanism and Prediction of Gas Permeation through Sub-Nanometer Graphene Pores: Comparison of Theory and Simulation. (United States)

    Yuan, Zhe; Govind Rajan, Ananth; Misra, Rahul Prasanna; Drahushuk, Lee W; Agrawal, Kumar Varoon; Strano, Michael S; Blankschtein, Daniel


    Due to its atomic thickness, porous graphene with sub-nanometer pore sizes constitutes a promising candidate for gas separation membranes that exhibit ultrahigh permeances. While graphene pores can greatly facilitate gas mixture separation, there is currently no validated analytical framework with which one can predict gas permeation through a given graphene pore. In this work, we simulate the permeation of adsorptive gases, such as CO2 and CH4, through sub-nanometer graphene pores using molecular dynamics simulations. We show that gas permeation can typically be decoupled into two steps: (1) adsorption of gas molecules to the pore mouth and (2) translocation of gas molecules from the pore mouth on one side of the graphene membrane to the pore mouth on the other side. We find that the translocation rate coefficient can be expressed using an Arrhenius-type equation, where the energy barrier and the pre-exponential factor can be theoretically predicted using the transition state theory for classical barrier crossing events. We propose a relation between the pre-exponential factor and the entropy penalty of a gas molecule crossing the pore. Furthermore, on the basis of the theory, we propose an efficient algorithm to calculate CO2 and CH4 permeances per pore for sub-nanometer graphene pores of any shape. For the CO2/CH4 mixture, the graphene nanopores exhibit a trade-off between the CO2 permeance and the CO2/CH4 separation factor. This upper bound on a Robeson plot of selectivity versus permeance for a given pore density is predicted and described by the theory. Pores with CO2/CH4 separation factors higher than 10(2) have CO2 permeances per pore lower than 10(-22) mol s(-1) Pa(-1), and pores with separation factors of ∼10 have CO2 permeances per pore between 10(-22) and 10(-21) mol s(-1) Pa(-1). Finally, we show that a pore density of 10(14) m(-2) is required for a porous graphene membrane to exceed the permeance-selectivity upper bound of polymeric materials

  13. Self-assembling organic nanotubes with precisely defined, sub-nanometer pores: formation and mass transport characteristics. (United States)

    Gong, Bing; Shao, Zhifeng


    The transport of molecules and ions across nanometer-scaled pores, created by natural or artificial molecules, is a phenomenon of both fundamental and practical significance. Biological channels are the most remarkable examples of mass transport across membranes and demonstrate nearly exclusive selectivity and high efficiency with a diverse collection of molecules. These channels are critical for many basic biological functions, such as membrane potential, signal transduction, and osmotic homeostasis. If such highly specific and efficient mass transport or separation could be achieved with artificial nanostructures under controlled conditions, they could create revolutionary technologies in a variety of areas. For this reason, investigators from diverse disciplines have vigorously studied small nondeformable nanopores. The most exciting studies have focused on carbon nanotubes (CNTs), which have exhibited fast mass transport and high ion selectivity despite their very simple structure. However, the limitations of CNTs and the dearth of other small (≤2 nm) nanopores have severely hampered the systematic investigation of nanopore-mediated mass transport, which will be essential for designing artificial nanopores with desired functions en masse. Researchers can overcome the difficulties associated with CNT and other artificial pores by stacking macrocyclic building blocks with persistent shapes to construct tunable, self-assembling organic pores. This effort started when we discovered a highly efficient, one-pot macrocyclization process to efficiently prepare several classes of macrocycles with rigid backbones containing nondeformable cavities. Such macrocycles, if stacked atop one another, should lead to nanotubular assemblies with defined inner pores determined by their constituent macrocycles. One class of macrocycles with aromatic oligoamide backbones had a very high propensity for directional assembly, forming nanotubular structures containing nanometer and sub-nanometer

  14. Effect of electric field gradient on sub-nanometer spatial resolution of tip-enhanced Raman spectroscopy. (United States)

    Meng, Lingyan; Yang, Zhilin; Chen, Jianing; Sun, Mengtao


    Tip-enhanced Raman spectroscopy (TERS) with sub-nanometer spatial resolution has been recently demonstrated experimentally. However, the physical mechanism underlying is still under discussion. Here we theoretically investigate the electric field gradient of a coupled tip-substrate system. Our calculations suggest that the ultra-high spatial resolution of TERS can be partially attributed to the electric field gradient effect owning to its tighter spatial confinement and sensitivity to the infrared (IR)-active of molecules. Particularly, in the case of TERS of flat-lying H₂TBPP molecules,we find the electric field gradient enhancement is the dominating factor for the high spatial resolution, which qualitatively coincides with previous experimental report. Our theoretical study offers a new paradigm for understanding the mechanisms of the ultra-high spatial resolution demonstrated in tip-enhanced spectroscopy which is of importance but neglected.

  15. Differential optical shadow sensor for sub-nanometer displacement measurement and its application to drag-free satellites. (United States)

    Zoellner, Andreas; Tan, Si; Saraf, Shailendhar; Alfauwaz, Abdul; DeBra, Dan; Buchman, Sasha; Lipa, John A


    We present a method for 3D sub-nanometer displacement measurement using a set of differential optical shadow sensors. It is based on using pairs of collimated beams on opposite sides of an object that are partially blocked by it. Applied to a sphere, our 3-axis sensor module consists of 8 parallel beam-detector sets for redundancy. The sphere blocks half of each beam's power in the nominal centered position, and any displacement can be measured by the differential optical power changes amongst the pairs of detectors. We have experimentally demonstrated a displacement sensitivity of 0.87nm/Hz at 1 Hz and 0.39nm/Hz at 10 Hz. We describe the application of the module to the inertial sensor of a drag-free satellite, which can potentially be used for navigation, geodesy and fundamental science experiments as well as ground based applications.

  16. Ultra-stable and versatile widefield cryo-fluorescence microscope for single-molecule localization with sub-nanometer accuracy. (United States)

    Li, Weixing; Stein, Simon C; Gregor, Ingo; Enderlein, Jörg


    We developed a stand-alone cryostat with optical access to the sample which can be adapted to any epi-fluorescence microscope for single-molecule fluorescence spectroscopy and imaging. The cryostat cools the sample to a cryogenic temperature of 89 K, and allows for imaging single molecules using an air objective with a numerical aperture of 0.7. An important property of this system is its excellent thermal and mechanical stability, enabling long-time observations of samples over several hours with negligible drift. Using this system, we performed photo-bleaching studies of Atto647N dye molecules, and find an improvement of the photostability of these molecules by more than two orders of magnitude. The resulting increased photon numbers of several millions allow for single-molecule localization accuracy of sub-nanometer.

  17. Chemical vapor deposition-prepared sub-nanometer Zr clusters on Pd surfaces: promotion of methane dry reforming. (United States)

    Mayr, Lukas; Shi, Xue-Rong; Köpfle, Norbert; Milligan, Cory A; Zemlyanov, Dmitry Y; Knop-Gericke, Axel; Hävecker, Michael; Klötzer, Bernhard; Penner, Simon


    An inverse Pd-Zr model catalyst was prepared by chemical vapor deposition (CVD) using zirconium-t-butoxide (ZTB) as an organometallic precursor. Pd-Zr interaction was then investigated with focus on the correlation of reforming performance with the oxidation state of Zr. As test reactions, dry reforming of methane (DRM) and methanol steam reforming (MSR) were chosen. Depending on treatments, either ZrOxHy or ZrO2 overlayers or Zr as sub-nanometer clusters could be obtained. Following the adsorption of ZTB on Pd(111), a partially hydroxylated Zr4+-containing layer was formed, which can be reduced to metallic Zr by thermal annealing in ultrahigh vacuum, leading to redox-active Zr0 sub-nanometer clusters. Complementary density functional theoretical (DFT) calculations showed that a single layer of ZrO2 on Pd(111) can be more easily reduced toward the metallic state than a double- and triple layer. Also, the initial and resulting layer compositions greatly depend on gas environment. The lower the water background partial pressure, the faster and more complete the reduction of Zr4+ species to Zr0 on Pd takes place. Under methanol steam reforming conditions, water activation by hydroxylation of Zr occurs. In excess of methanol, strong coking is induced by the Pd/ZrOxHy interface. In contrast, dry reforming of methane is effectively promoted if these initially metallic Zr species are present in the pre-catalyst, leading to a Pd/ZrOxHy phase boundary by oxidative activation under reaction conditions. These reaction-induced active sites for DRM are stable with respect to carbon blocking or coking. In essence, Zr doping of Pd opens specific CO2 activation channels, which are absent on pure metallic Pd.

  18. Thermally tunable quadruple Vernier racetrack resonators. (United States)

    Boeck, Robert; Chrostowski, Lukas; Jaeger, Nicolas A F


    The spectral responses of series-coupled racetrack resonators exhibiting the Vernier effect have many attractive features as compared to the spectral responses of identical series-coupled racetrack resonators, such as free spectral range (FSR) extension and enhanced wavelength tunability. Here we present experimental results of a thermally tunable quadruple series-coupled silicon racetrack resonator exhibiting the Vernier effect. We thermally tune two of the four racetrack resonators to enable discrete switching of the major peak by 15.54 nm. Also, our device has an interstitial peak suppression of 35.4 dB, a 3 dB bandwidth of 0.45 nm, and an extended FSR of 37.66 nm.

  19. The Computational Complexity of RaceTrack (United States)

    Holzer, Markus; McKenzie, Pierre

    Martin Gardner in the early 1970's described the game of RaceTrack [M. Gardner, Mathematical games - Sim, Chomp and Race Track: new games for the intellect (and not for Lady Luck), Scientific American, 228(1):108-115, Jan. 1973]. Here we study the complexity of deciding whether a RaceTrack player has a winning strategy. We first prove that the complexity of RaceTrack reachability, i.e., whether the finish line can be reached or not, crucially depends on whether the car can touch the edge of the carriageway (racetrack): the non-touching variant is NL-complete while the touching variant is equivalent to the undirected grid graph reachability problem, a problem in L but not known to be L-hard. Then we show that single-player RaceTrack is NL-complete, regardless of whether driving on the track boundary is allowed or not, and that deciding the existence of a winning strategy in Gardner's original two-player game is P-complete. Hence RaceTrack is an example of a game that is interesting to play despite the fact that deciding the existence of a winning strategy is most likely not NP-hard.

  20. Direct sub-nanometer scale electron microscopy analysis of anion incorporation to self-ordered anodic alumina layers

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rovira, L.; Lopez-Haro, M.; Hungria, A.B.; El Amrani, K. [Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, University of Cadiz, Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain); Sanchez-Amaya, J.M. [Titania, Ensayos y Proyectos Industriales, S.L. Parque Tecnobahia, Edificio RETSE, Nave 4, 11500 El Puerto de Santa Maria (Cadiz) (Spain); Calvino, J.J. [Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, University of Cadiz, Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain); Botana, F.J., E-mail: javier.botana@uca.e [Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, University of Cadiz, Republica Saharaui s/n, 11510 Puerto Real, Cadiz (Spain)


    Research highlights: {yields} Morphological and chemical characterization at atomic scale of porous alumina layers anodised in ordered regimes. {yields} Characterization based on the use of FEG-SEM, STEM-HAADF, STEM-EELS and STEM-X-EDS. {yields} Nanoscale distribution of P-, C- and S-bearing species in the pore wall. - Abstract: Ordered porous alumina layers prepared by two-step anodising in phosphoric, oxalic and sulphuric acids have been characterized at sub-nanometer scale using electron microscopy techniques. FEG-SEM and STEM-HAADF images allowed estimating the pore size, cell wall and pore wall thicknesses of the layers. Nanoanalytical characterization has been performed by STEM-EELS and STEM-X-EDS. Detailed features of the spatial distribution of anions in the pore wall of the films have been obtained. Maximum concentration of P-species occurs, approximately, at the middle of the pore wall; adjacent to the pore for C-species, whereas the distribution of S-species appears to be uniform.

  1. Self-focusing skyrmion racetracks in ferrimagnets (United States)

    Kim, Se Kwon; Lee, Kyung-Jin; Tserkovnyak, Yaroslav


    We theoretically study the dynamics of ferrimagnetic skyrmions in inhomogeneous metallic films close to the angular momentum compensation point. In particular, it is shown that the line of the vanishing angular momentum can be utilized as a self-focusing racetrack for skyrmions. To that end, we begin by deriving the equations of motion for the dynamics of collinear ferrimagnets in the presence of a charge current. The obtained equations of motion reduce to those of ferromagnets and antiferromagnets at two special limits. In the collective coordinate approach, a skyrmion behaves as a massive charged particle moving in a viscous medium subjected to a magnetic field. Analogous to the snake orbits of electrons in a nonuniform magnetic field, we show that a ferrimagnet with nonuniform angular momentum density can exhibit the snake trajectories of skyrmions, which can be utilized as racetracks for skyrmions.

  2. Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO2 transformation (United States)

    Shanmugam, Ramasamy; Thamaraichelvan, Arunachalam; Ganesan, Tharumeya Kuppusamy; Viswanathan, Balasubramanian


    Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO2 to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO2 to CO at an applied potential of -0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO2 to various value added chemicals.

  3. An Improved Racetrack Structure for Transporting a Skyrmion. (United States)

    Lai, P; Zhao, G P; Tang, H; Ran, N; Wu, S Q; Xia, J; Zhang, X; Zhou, Y


    Magnetic skyrmions are promising building blocks for next generation data storage due to their stability, small size and extremely low currents to drive them, which can be used instead of traditional magnetic domain walls to store information as data bits in metalic racetrack memories. However, skyrmions can drift from the direction of electron flow due to the Magnus force and thus may annihilate at the racetrack edges, resulting in the loss of information. Here we propose a new skyrmion-based racetrack structure by adding high-K materials (materials with high magnetic crystalline anisotropy) at the edges, which confines the skyrmions in the center region of the metalic racetrack efficiently. This design can overcome both the clogging and annihilation of skyrmions according to our micromagnetic simulation, which occur normally for skyrmions moving on a racetrack under small and large driving currents, respectively. Phase diagrams for skyrmion motion on the proposed racetrack with various values of current density and racetrack edge width have been calculated and given, showing that skyrmions can be driven at a high speed (about 300 m/s) in the racetrack under relatively smaller driving currents. This design offers the possiblity of building an ultrafast and energy-efficient skyrmion transport device.

  4. Sub-nanometer surface chemistry and orbital hybridization in lanthanum-doped ceria nano-catalysts revealed by 3D electron microscopy. (United States)

    Collins, Sean M; Fernandez-Garcia, Susana; Calvino, José J; Midgley, Paul A


    Surface chemical composition, electronic structure, and bonding characteristics determine catalytic activity but are not resolved for individual catalyst particles by conventional spectroscopy. In particular, the nano-scale three-dimensional distribution of aliovalent lanthanide dopants in ceria catalysts and their effect on the surface electronic structure remains unclear. Here, we reveal the surface segregation of dopant cations and oxygen vacancies and observe bonding changes in lanthanum-doped ceria catalyst particle aggregates with sub-nanometer precision using a new model-based spectroscopic tomography approach. These findings refine our understanding of the spatially varying electronic structure and bonding in ceria-based nanoparticle aggregates with aliovalent cation concentrations and identify new strategies for advancing high efficiency doped ceria nano-catalysts.

  5. Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO{sub 2} transformation

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, Ramasamy [Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625 009 (India); National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India); Thamaraichelvan, Arunachalam [Faculty of Allied Health Sciences, Chettinad Hospital & Research Institute, Kelambakkam, Tamilnadu 603 103 (India); Ganesan, Tharumeya Kuppusamy [Department of Chemistry, The American College, Madurai, Tamilnadu 625 002 (India); Viswanathan, Balasubramanian, E-mail: [National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India)


    Highlights: • On interaction with adsorbate CO{sub 2,} the adsorbent changes its configuration around the metal. • Electron transfer is faster in low coordinative environment of Cu. • CO formation is more favorable on Cu sites with even coordination number. • Cu at coordination number two has a over potential of −0.35 V. - Abstract: Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO{sub 2} to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO{sub 2} to CO at an applied potential of −0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO{sub 2} to various value added chemicals.

  6. Studies of plasma confinement in linear and RACETRACK mirror configurations

    Energy Technology Data Exchange (ETDEWEB)

    Kuthi, A.; Wong, A.Y.


    This report discusses research on the following magnetic mirror configurations: Racetrack; ECRH generated plasmas; RF generated plasmas; potential structures; surface multipole fields, and lamex; hot electron physics; axial loss processes; and RF induced effects.

  7. Superconducting racetrack booster for the ion complex of MEIC

    Energy Technology Data Exchange (ETDEWEB)

    Filatov, Yu [Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation); Moscow Inst. of Physics and Technology (MIPT), Moscow (Russian Federation); Kondratenko, A. M. [Science and Technique Laboratory ' Zaryad' , 630090, Novosibirsk, Russia; Kondratenko, M. A. [Science and Technique Laboratory ' Zaryad' , 630090, Novosibirsk, Russia; Kovalenko, A. [Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation); Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Lin, Fanglei [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Morozov, Vasiliy S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)


    The current design of the Medium-energy Electron-Ion Collider (MEIC) project at Jefferson lab features a single 8 GeV/c figure-8 booster based on super-ferric magnets. Reducing the circumference of the booster by switching to a racetrack design may improve its performance by limiting the space charge effect and lower its cost. We consider problems of preserving proton and deuteron polarizations in a superconducting racetrack booster. We show that using magnets based on hollow high-current NbTi composite superconducting cable similar to those designed at JINR for the Nuclotron guarantees preservation of the ion polarization in a racetrack booster up to 8 GeV/c. The booster operation cycle would be a few seconds that would improve the operating efficiency of the MEIC ion complex.

  8. Shortcuts in multiple dimensions: the multiaxial racetrack filter

    Directory of Open Access Journals (Sweden)

    M.A. Meggiolaro


    Full Text Available Filtering techniques have been proposed for multiaxial load histories, usually aiming to filter out non-reversals, i.e. sampling points that do not constitute a reversal in any of its stress or strain components. However, the path between two reversals is needed to evaluate the equivalent stress or strain associated with each event. Filtering out too many points in such path would almost certainly result in lower equivalent stresses or strains than expected. To avoid such issues, it is important to consider how a measured multiaxial loading path deviates from its course using some metric, such as the von Mises stress or strain. In this work, a multiaxial version of the racetrack filter is proposed, which is able to perform efficient filtering even for 6D nonproportional histories. In the Multiaxial Racetrack algorithm, the stress or strain history is represented in a 6D space, only requiring from the user a desired scalar filtering amplitude r. For uniaxial histories, the proposed algorithm exactly reproduces the classic racetrack filter. The efficiency of the proposed Multiaxial Racetrack filter is qualitatively verified from a tension-torsion history example, showing the reduction in the number of data points for larger filter amplitudes r. The procedure can efficiently filter out non-damaging events but preserving the overall multiaxial path shape and multiaxial reversion points, which usually do not coincide with the reversion points of individual stress or strain components.

  9. Performance of synthetic antiferromagnetic racetrack memory: domain wall versus skyrmion

    KAUST Repository

    Tomasello, R


    A storage scheme based on racetrack memory, where the information can be coded in a domain or a skyrmion, seems to be an alternative to conventional hard disk drive for high density storage. Here, we perform a full micromagnetic study of the performance of synthetic antiferromagnetic (SAF) racetrack memory in terms of velocity and sensitivity to defects by using experimental parameters. We find that, to stabilize a SAF skyrmion, the Dzyaloshinskii–Moriya interaction in the top and the bottom ferromagnet should have an opposite sign. The velocity of SAF skyrmions and SAF Néel domain walls are of the same order and can reach values larger than 1200 m s−1 if a spin–orbit torque from the spin-Hall effect with opposite sign is applied to both ferromagnets. The presence of disordered anisotropy in the form of randomly distributed grains introduces a threshold current for both SAF skyrmions and SAF domain walls motions.

  10. Design and Fabrication of Racetrack Coil Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A.; McInturff, A.D.; Millos, G.; Morrison, L.; Morrison, M.; Scanlan, R.M.


    Most accelerator magnets for applications in the field range up to 9 T utilize NbTi superconductor and a cosine theta coil design. For fields above 9 T, it is necessary to use Nb{sub 3}Sn or other strain sensitive materials, and other coil geometries that are more compatible with these materials must be considered. This paper describes their recent efforts to design a series of racetrack coil magnets that will provide experimental verification of this alternative magnet design for a dual aperture dipole magnet with the goal of reaching a field level of 15 T, will be described. The experimental program, which consists of a series of steps leading to a high field accelerator quality magnet, will be presented. Fabrication of a racetrack dipole magnet utilizing Nb{sub 3}Sn superconductor and a wind and react approach will be presented.

  11. Numerical simulation of eigenmodes of ring and race-track optical microresonators (United States)

    Raskhodchikov, A. V.; Raskhodchikov, D. V.; Scherbak, S. A.; Lipovskii, A. A.


    We have performed a numerical study of whispering gallery modes of ring and race-track optical microresonators. Mode excitation was considered and their spectra and electromagnetic field distributions were calculated via numerical solution of the Helmholtz equation. We pay additional attention to features of eigenmodes in race-tracks in contrast with ring resonators. Particularly, we demonstrate that modes in race-tracks are not “classic” WGM in terms of total internal reflection from a single boundary, and an inner boundary is essential for their formation. The dependence of effective refractive index of race-tracks modes on the resonator width is shown.

  12. Rise of Racetrack Memory! Domain Wall Spin-Orbitronics (United States)

    Parkin, Stuart

    Memory-storage devices based on the current controlled motion of a series of domain walls (DWs) in magnetic racetracks promise performance and reliability beyond that of conventional magnetic disk drives and solid state storage devices (1). Racetracks that are formed from atomically thin, perpendicularly magnetized nano-wires, interfaced with adjacent metal layers with high spin-orbit coupling, give rise to domain walls that exhibit a chiral Néel structure (2). These DWs can be moved very efficiently with current via chiral spin-orbit torques (2,3). Record-breaking current-induced DW speeds exceeding 1,000 m/sec are found in synthetic antiferromagnetic structures (3) in which the net magnetization of the DWs is tuned to almost zero, making them ``invisible''. Based on these recent discoveries, Racetrack Memory devices have the potential to operate on picosecond timescales and at densities more than 100 times greater than other memory technologies. (1) S.S.P. Parkin et al., Science 320, 5873 (2008); S.S.P. Parkin and S.-H. Yang, Nat. Nano. 10, 195 (2015). (2) K.-S. Ryu metal. Nat. Nano. 8, 527 (2013). (3) S.-H. Yang, K.-S. Ryu and S.S.P. Parkin, Nat. Nano. 10, 221 (2015). (4). S.S.P. Parkin, Phys. Rev. Lett. 67, 3598 (1991).

  13. Effects of a Picture Racetrack Game on the Expressive Vocabulary of Deaf Preschoolers (United States)

    Davenport, Carrie A.; Alber-Morgan, Sheila R.; Clancy, Shannon M.; Kranak, Michael P.


    This study examined the effects of a picture racetrack game on the acquisition, maintenance, and generalization of picture labeling for 2 preschool students who are deaf. The game consisted of placing photographs representing individualized target vocabulary around a racetrack board and prompting the participant to sign each photo. A multiple…

  14. Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory. (United States)

    Zhang, Xichao; Zhao, G P; Fangohr, Hans; Liu, J Ping; Xia, W X; Xia, J; Morvan, F J


    Magnetic skyrmions are promising for building next-generation magnetic memories and spintronic devices due to their stability, small size and the extremely low currents needed to move them. In particular, skyrmion-based racetrack memory is attractive for information technology, where skyrmions are used to store information as data bits instead of traditional domain walls. Here we numerically demonstrate the impacts of skyrmion-skyrmion and skyrmion-edge repulsions on the feasibility of skyrmion-based racetrack memory. The reliable and practicable spacing between consecutive skyrmionic bits on the racetrack as well as the ability to adjust it are investigated. Clogging of skyrmionic bits is found at the end of the racetrack, leading to the reduction of skyrmion size. Further, we demonstrate an effective and simple method to avoid the clogging of skyrmionic bits, which ensures the elimination of skyrmionic bits beyond the reading element. Our results give guidance for the design and development of future skyrmion-based racetrack memory.

  15. Shapes of coil ends in racetrack layout for superconducting magnets

    CERN Document Server

    Milanese, A


    Racetrack coils have received considerable attention for Nb3Sn magnets, both built using the React-and-Wind and Wind-and-React techniques. The geometry usually consists of a series of straight parts connected with circular arcs. Therefore, at the interface between these sections, a finite change in curvature is imposed on the cable. Alternative transition curves are analyzed here, with a particular focus on the total strain energy and the minimum / maximum radii of curvature. The study is presented in dimensionless form and the various alternatives are detailed in mathematical terms, so to be used for drafting or simulations. Extensions for the design of flared ends are also briefly discussed.

  16. Experimental performance of DWDM quadruple Vernier racetrack resonators. (United States)

    Boeck, Robert; Flueckiger, Jonas; Chrostowski, Lukas; Jaeger, Nicolas A F


    We demonstrate that one can meet numerous commercial requirements for filters used in dense wavelength-division multiplexing applications using quadruple Vernier racetrack resonators in the silicon-on-insulator platform. Experimental performance shows a ripple of 0.2 dB, an interstitial peak suppression of 39.7 dB, an adjacent channel isolation of 37.2 dB, an express channel isolation of 10.2 dB, and a free spectral range of 37.52 nm.

  17. A strategy for the design of skyrmion racetrack memories. (United States)

    Tomasello, R; Martinez, E; Zivieri, R; Torres, L; Carpentieri, M; Finocchio, G


    Magnetic storage based on racetrack memory is very promising for the design of ultra-dense, low-cost and low-power storage technology. Information can be coded in a magnetic region between two domain walls or, as predicted recently, in topological magnetic objects known as skyrmions. Here, we show the technological advantages and limitations of using Bloch and Néel skyrmions manipulated by spin current generated within the ferromagnet or via the spin-Hall effect arising from a non-magnetic heavy metal underlayer. We found that the Néel skyrmion moved by the spin-Hall effect is a very promising strategy for technological implementation of the next generation of skyrmion racetrack memories (zero field, high thermal stability, and ultra-dense storage). We employed micromagnetics reinforced with an analytical formulation of skyrmion dynamics that we developed from the Thiele equation. We identified that the excitation, at high currents, of a breathing mode of the skyrmion limits the maximal velocity of the memory.

  18. Shapes of coil ends in racetrack layout for superconducting magnets

    CERN Document Server

    Milanese, A


    Racetrack coils have received considerable attention for Nb3Sn magnets, both built using the React-and-Wind and Wind-and-React techniques. The geometry usually consists of a series of straight parts connected with circular arcs. Therefore, at the interface between these sections, a finite change in curvature is imposed on the cable. Alternative transition curves are analyzed here, with a particular focus on the total strain energy and the minimum / maximum radii of curvature. The study is presented in dimensionless form and the various alternatives are detailed in mathematical terms, so to be used for drafting or simulations. Extensions for the design of flared ends are also briefly discussed. This study is within the framework of the EuCARD WP7-HFM project. In particular, the proposed curve can be used for the end design of the high field model magnet (Task 7.3).

  19. Ice rafts not sails: Floating the rocks at Racetrack Playa (United States)

    Lorenz, Ralph D.; Jackson, Brian K.; Barnes, Jason W.; Spitale, Joe; Keller, John M.


    We suggest that the existence of many of the rock-carved trails at Racetrack Playa in Death Valley National Park is predominantly due to the effect of arbitrarily weak winds on rocks that are floated off the soft bed by small rafts of ice, as also occurs in arctic tidal beaches to form boulder barricades. These ice cakes need not have a particularly large surface area if the ice is adequately thick—the ice cakes allow the rocks to move by buoyantly reducing the reaction and friction forces at the bed, not by increasing the wind drag. The parameter space of ice thickness and extent versus rock size for flotation is calculated and found to be reasonable. We demonstrate the effect with a simple experiment.

  20. Stability of the phase motion in race-track microtrons (United States)

    Kubyshin, Yu. A.; Larreal, O.; Ramírez-Ros, R.; Seara, T. M.


    We model the phase oscillations of electrons in race-track microtrons by means of an area preserving map with a fixed point at the origin, which represents the synchronous trajectory of a reference particle in the beam. We study the nonlinear stability of the origin in terms of the synchronous phase -the phase of the synchronous particle at the injection. We estimate the size and shape of the stability domain around the origin, whose main connected component is enclosed by an invariant curve. We describe the evolution of the stability domain as the synchronous phase varies. We also clarify the role of the stable and unstable invariant curves of some hyperbolic (fixed or periodic) points.

  1. Reference News Release: United States Announces Settlement of Clean Water Act Violations at Aqueduct Racetrack (United States)

    The complaint alleges that NYRA, which operates the Aqueduct Racetrack where horse racing, training, and boarding of horses occur, and where up to 450 horses are housed on site during the horse racing season, violated the Clean Water Act

  2. Low-scale inflation and supersymmetry breaking in racetrack models (United States)

    Allahverdi, Rouzbeh; Dutta, Bhaskar; Sinha, Kuver


    In many moduli stabilization schemes in string theory, the scale of inflation appears to be of the same order as the scale of supersymmetry breaking. For low-scale supersymmetry breaking, therefore, the scale of inflation should also be low, unless this correlation is avoided in specific models. We explore such a low-scale inflationary scenario in a racetrack model with a single modulus in type IIB string theory. Inflation occurs near a point of inflection in the Kähler modulus potential. Obtaining acceptable cosmological density perturbations leads to the introduction of magnetized D7-branes sourcing nonperturbative superpotentials. The gravitino mass, m3/2, is chosen to be around 30 TeV, so that gravitinos that are produced in the inflaton decay do not affect big-bang nucleosynthesis. Supersymmetry is communicated to the visible sector by a mixture of anomaly and modulus mediation. We find that the two sources contribute equally to the gaugino masses, while scalar masses are decided mainly by anomaly contribution. This happens as a result of the low scale of inflation and can be probed at the LHC.

  3. Voltage Controlled Magnetic Skyrmion Motion for Racetrack Memory. (United States)

    Kang, Wang; Huang, Yangqi; Zheng, Chentian; Lv, Weifeng; Lei, Na; Zhang, Youguang; Zhang, Xichao; Zhou, Yan; Zhao, Weisheng


    Magnetic skyrmion, vortex-like swirling topologically stable spin configurations, is appealing as information carrier for future nanoelectronics, owing to the stability, small size and extremely low driving current density. One of the most promising applications of skyrmion is to build racetrack memory (RM). Compared to domain wall-based RM (DW-RM), skyrmion-based RM (Sky-RM) possesses quite a few benefits in terms of energy, density and speed etc. Until now, the fundamental behaviors, including nucleation/annihilation, motion and detection of skyrmion have been intensively investigated. However, one indispensable function, i.e., pinning/depinning of skyrmion still remains an open question and has to be addressed before applying skyrmion for RM. Furthermore, Current research mainly focuses on physical investigations, whereas the electrical design and evaluation are still lacking. In this work, we aim to promote the development of Sky-RM from fundamental physics to realistic electronics. First, we investigate the pinning/depinning characteristics of skyrmion in a nanotrack with the voltage-controlled magnetic anisotropy (VCMA) effect. Then, we propose a compact model and design framework of Sky-RM for electrical evaluation. This work completes the elementary memory functionality of Sky-RM and fills the technical gap between the physicists and electronic engineers, making a significant step forward for the development of Sky-RM.

  4. Measurement of a Conduction Cooled Nb3Sn Racetrack Coil (United States)

    Kim, HS; Kovacs, C.; Rochester, J.; Sumption, MD; Tomsic, M.; Peng, X.; Doll, D.


    Use of superconducting coils for wind turbines and electric aircraft is of interest because of the potential for high power density and weight reduction. Here we test a racetrack coil developed as a proof-of-concept for cryogen-free superconducting motors and generators. The coil was wound with 1209 m of 0.7-mm-diameter insulated tube-type Nb3Sn wire. The coil was epoxy-impregnated, instrumented, covered with numerous layers of aluminized mylar insulation, and inserted vertically into a dewar. The system was cooled to 4.2 K, and a few inches of liquid helium was allowed to collect at the bottom of the dewar but below the coil. The coil was cooled by conduction via copper cooling bars were attached to the coil but also were immersed in the liquid helium at their lower ends. Several current tests were performed on the coil, initially in voltage mode, and one run in current mode. The maximum coil Ic at 4.2 K was 480 A, generating 3.06 T at the surface of the coil. The coil met the design targets with a noticeable margin.

  5. Effects of a Picture Racetrack Game on the Expressive Vocabulary of Deaf Preschoolers. (United States)

    Davenport, Carrie A; Alber-Morgan, Sheila R; Clancy, Shannon M; Kranak, Michael P


    This study examined the effects of a picture racetrack game on the acquisition, maintenance, and generalization of picture labeling for 2 preschool students who are deaf. The game consisted of placing photographs representing individualized target vocabulary around a racetrack board and prompting the participant to sign each photo. A multiple baseline design across picture sets demonstrated that playing the picture racetrack game was functionally related to acquisition of vocabulary to 100% mastery on at least 3 consecutive sessions for each participant. Additionally, both participants maintained most of the vocabulary they acquired for at least 4 weeks after intervention, and they generalized picture labeling to a different presentation mode (i.e., a photo album). © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  6. Inductance optimization of miniature Broadband transformers with racetrack shaped ferrite cores for Ethernet applications (United States)

    Bowen, David; Krafft, Charles; Mayergoyz, Isaak D.


    There is strong commercial interest in the ability to fabricate the windings of traditional miniature wire-wound inductive circuit components, such as Ethernet transformers, lithographically. For greater inductance devices, thick cores are required, making the process of embedding the ferrite material within circuit board one of few options for lithographic winding fabrication. In this paper, a non-traditional core shape, suitable for embedding in circuit board, is examined analytically and experimentally; the racetrack shape is two halves of a toroid connected by straight legs. With regard to the high inductance requirements for Ethernet applications (350μH), the racetrack transformer inductance is analytically optimized, determining the optimal physical dimensions. Two sizes of racetrack-core transformers were fabricated and measured. The measured inductance was in reasonable agreement with the analytical prediction, though large variations in material permeability are expected from the mechanical processing of the ferrite. Some of the experimental transformers were observed to satisfy the Ethernet inductance requirement.

  7. Experimental characterization of dielectric-loaded plasmonic waveguide-racetrack resonators at near-infrared wavelengths

    DEFF Research Database (Denmark)

    Garcia, Cesar; Coello, Victor; Han, Zhanghua


    Dielectric-loaded plasmonic waveguide-racetrack resonators (WRTRs) were designed and fabricated for operating at near-infrared wavelengths (750–850 nm) and characterized using leakage-radiation microscopy. The transmission spectra of the WRTRs are found experimentally and compared to the calculat...

  8. Sensitivity analysis of silicon-on-insulator quadruple Vernier racetrack resonators (United States)

    Boeck, Robert; Chrostowski, Lukas; Jaeger, Nicolas A. F.


    We present a theoretical sensitivity analysis of silicon-on-insulator quadruple Vernier racetrack resonators based on varying, one at a time, various fabrication-dependent parameters. These parameters include the waveguide widths, heights, and propagation losses. We show that it should be possible to design a device that meets typical commercial specifications while being tolerant to changes in these parameters.

  9. Testing relativity again, laser, laser, laser, laser

    NARCIS (Netherlands)

    Einstein, A.


    laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser,

  10. Studies of plasma confinement in linear and RACETRACK mirror configurations. Progress report, January 1--October 31, 1986

    Energy Technology Data Exchange (ETDEWEB)

    Kuthi, A.; Wong, A.Y.


    This report discusses research on the following magnetic mirror configurations: Racetrack; ECRH generated plasmas; RF generated plasmas; potential structures; surface multipole fields, and lamex; hot electron physics; axial loss processes; and RF induced effects.

  11. Development of a large aperture Nb$_{3}$ Sn racetrack quadrupole magnet

    CERN Document Server

    Ferracin, Paolo; Caspi, Shlomo; Dietderich, D R; Gourlay, Stephen A; Hafalia, Aurelio R; Hannaford, C R; Lietzke, A F; Mattafirri, Sara; McInturff, A D; Nyman, M A; Sabbi, Gianluca


    The U.S. LHC Accelerator Research Program (LARP), a collaboration between BNL, FNAL, LBNL, and SLAC, has among its major objectives the development of advanced magnet technology for an LHC luminosity upgrade. The LBNL Superconducting Magnet Group supports this program with a broad effort involving design studies, Nb/sub 3/Sn conductor development, mechanical models, and basic prototypes. This paper describes the development of a large aperture Nb/sub 3/Sn racetrack quadrupole magnet using four racetrack coils from the LBNL Subscale Magnet (SM) Program. The magnet provides a gradient of 95 T/m in a 110 mm bore, with a peak field in the conductor of 11.2 T. The coils are pre-stressed by a mechanical structure based on a pre-tensioned aluminum shell, and axially supported with aluminum rods. The mechanical behavior has been monitored with strain gauges and the magnetic field has been measured. Results of the test are reported and analyzed.

  12. A FODO racetrack ring for nuSTORM: design and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A.; Bross, A.; Neuffer, D.


    The goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a circumference of ~ 480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS . Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize the arc length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.

  13. Cascade-coupled racetrack resonators based on the Vernier effect in the mid-infrared. (United States)

    Troia, Benedetto; Khokhar, Ali Z; Nedeljkovic, Milos; Penades, Jordi Soler; Passaro, Vittorio M N; Mashanovich, Goran Z


    In this paper we report the experimental demonstration of racetrack resonators in silicon-on-insulator technology platform operating in the mid-infrared wavelength range of 3.7-3.8 μm. Insertion loss lower than 1 dB and extinction ratio up to 30 dB were measured for single resonators. The experimental characterization of directional couplers and bending losses in silicon rib waveguides are also reported. Furthermore, we present the design and fabrication of cascade-coupled racetrack resonators based on the Vernier effect. Experimental spectra of Vernier architectures were demonstrated for the first time in the mid-infrared with insertion loss lower than 1 dB and maximum interstitial peak suppression of 10 dB.

  14. Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory


    Zhang, Xichao; Zhao, G. P.; Fangohr, Hans; Liu, J. Ping; Xia, W. X.; Xia, J.; Morvan, F. J.


    Magnetic skyrmions are promising for building next-generation magnetic memories and spintronic devices due to their stability, small size and the extremely low currents needed to move them. In particular, skyrmion-based racetrack memory is attractive for information technology, where skyrmions are used to store information as data bits instead of traditional domain walls. Here we numerically demonstrate the impacts of skyrmion-skyrmion and skyrmion-edge repulsions on the feasibility of skyrmi...

  15. Trail formation by ice-shoved "sailing stones" observed at Racetrack Playa, Death Valley National Park


    Lorenz, R. D.; Norris, J. M.; Jackson, B. K.; Norris, R. D.; Chadbourne, J. W.; Ray, J.


    Trails in the usually-hard mud of Racetrack Playa in Death Valley National Park attest to the seemingly-improbable movement of massive rocks on an exceptionally flat surface. The movement of these rocks, previously described as "sliding stones", "playa scrapers", "sailing stones" etc., has been the subject of speculation for almost a century but is an exceptionally rare phenomenon and until now has not been directly observed. Here we report documentation of multiple rock mov...

  16. Distal hindlimb kinematics of galloping Thoroughbred racehorses on dirt and synthetic racetrack surfaces. (United States)

    Symons, J E; Garcia, T C; Stover, S M


    The effect of racetrack surface (dirt or synthetic) on distal hindlimb kinematics of racehorses running at competition speeds is not known. To compare distal hindlimb and hoof kinematics during stance of breezing (unrestrained gallop) racehorses between dirt and synthetic surfaces. Two-dimensional kinematic video analysis of 5 Thoroughbred racehorses galloping at high speeds (12-17 m/s) on a dirt racetrack and a synthetic racetrack. The positions of kinematic markers applied to the left hindlimb were recorded at 500 Hz. Position, velocity and acceleration of joint angles and hoof translation during stance were calculated in the sagittal plane. Peak translational and angular kinematic values were compared between the dirt and synthetic race surfaces using mixed model analyses of covariance. Maximum and heel-strike metatarsophalangeal (fetlock) angles were greater (Pfetlock angle occurred earlier during stance on the dirt surface (Pfetlock hyperextension and horizontal hoof slide are greater on a dirt surface than on a synthetic surface. Synthetic race surfaces may mitigate risk of injury to hindlimb fetlock structures by reducing fetlock hyperextension and associated strains in fetlock support structures. Differences in hoof slide may contribute to different distal hindlimb kinematics between surfaces. © 2013 EVJ Ltd.

  17. A microtron accelerator for a free electron laser

    NARCIS (Netherlands)

    Botman, J.I.M.; Delhez, J.L.; Webers, G.A.; Hagedoorn, H.L.; Kleeven, W.J.G.M.; Timmermans, J.C.M.; Ernst, G.J.; Verschuur, Jeroen W.J.; Witteman, W.J.; Haselhoff, E.H.; Haselhoff, E.H.


    A racetrack microtron as a source for a free electron laser is being constructed. It will accelerate electrons up to 25 MeV to provide 10 ¿m radiation in a hybrid undulator with a periodicity distance of 25 mm. The aim is to accelerate 100 A bunches of 30 ps pulse length at 81.25 MHz. This frequency

  18. The effect of racetrack design on gait symmetry of the pacer. (United States)

    Crawford, W H; Leach, D H


    A survey of a western Canadian racetrack determined the superelevation and transition curves to be less than the cited design standards. High-speed cinematography was used to film seven Standardbred pacers as they proceeded around one curve of the track at racing speed and for each horse 19 temporal stride parameters were obtained from these films using a film analyzer system. Average velocities were calculated and the mean stride length was found to vary from 5.08 m to 5.77 m. In all frames analyzed the hind foot was observed to contact the track surface prior to the ipsilateral forefoot and all horses displayed significant (p less than 0.05) contralateral asymmetry of some temporal stride parameters. Fifteen temporal stride parameters were significantly different (p less than 0.05) when compared between horses but only three temporal stride parameters were significantly different (p less than 0.05) when their values were compared between segments of the curved portions of the track. It is suggested that temporal gait asymmetry should not be used to judge the standards of racetrack design.

  19. The Effects of DI Flashcards and Math Racetrack on Multiplication Facts for Two Elementary Students with Learning Disabilities (United States)

    Lund, Kaitlyn; McLaughlin, T. F.; Neyman, Jen; Everson, Mary


    The purpose of this study was to evaluate the effects of a Direct Instruction (DI) flashcard system paired with a math racetrack to teach basic multiplication facts to two elementary students diagnosed with learning disabilities. The study was conducted in a resource room which served intermediate aged elementary students. The school was located…

  20. [Depth dose characteristics of electron beams released from a scanning type Racetrack Microtron treatment machine]. (United States)

    Sato, Tomoharu


    The Racetrack Microtron MM50 capable of taking out x-rays and electron beams having a high energy of up to 50 MeV was evaluated by a dosimetry of electron beams in comparison with Microtron MM22. The MM50 flattens the intensity of electron beams by using the beam scanning method while the MM22 utilizes the flattening-filter method. A percentage depth dose (PDD) curve was obtained through the dosimetry of electron beams using a water phantom. As compared with the MM22, the MM50 emits an electron beam that has an energy much closer to the nominal one, that is less contaminated by x-rays, and whose intensity decreases steeply down to near zero on the PDD curve. The MM50 has an electron beam dose distribution that is practically useful since the dose tends to be concentrated on the target volume.

  1. A two-step multiaxial racetrack filter algorithm for non-proportional load histories

    Directory of Open Access Journals (Sweden)

    Marco Antonio Meggiolaro


    Full Text Available The recently proposed multiaxial racetrack filter (MRF is able to deal with general non-proportional multiaxial load histories. While only requiring a single user-defined scalar filter amplitude, the MRF is able to synchronously eliminate non-damaging events from any noisy multiaxial load history without changing the overall shape of its original path, a necessary condition to avoid introducing errors in fatigue damage assessments. The MRF procedures are optimized here by the introduction of a pre-processing “partitioning” step on the load history data, which selects candidates for the reversal points in a robust partitioning process, highly increasing the filter efficiency and decreasing its computational time. The improved MRF is evaluated through the fatigue analyses of over-sampled tension-torsion data measured in 316L stainless steel tubular specimens under non-proportional load paths.

  2. Terrain analysis of the racetrack basin and the sliding rocks of Death Valley (United States)

    Messina, P.; Stoffer, P.


    The Racetrack Playa's unusual surface features known as sliding rocks have been the subject of an ongoing debate and several mapping projects for half a century, although the causative mechanism remains unresolved. Clasts ranging in volume from large pebbles to medium boulders have, unwitnessed, maneuvered around the nearly flat dry lake over considerable distances. The controversy has persisted partly because eyewitness accounts of the phenomenon continue to be lacking, and the earlier mapping missions were limited in method and geographic range. In July 1996, we generated the first complete map of all observed sliding rock trails by submeter differential Global Positioning System (DGPS) mapping technology. The resulting map shows 162 sliding rocks and associated trails to an accuracy of approximately 30 cm. Although anemometer data are not available in the Racetrack wilderness, wind is clearly a catalyst for sliding rock activity; an inferred wind rose was constructed from DGPS trail segment data. When the entire trail network is examined in plan, some patterns emerge, although other (perhaps expected relations) remain elusive: terrain analysis of the surrounding topography demonstrates that the length and morphology of trails are more closely related to where rocks rested at the onset of motion than to any physical attribute of the rocks themselves. Follow-up surveys in May 1998, May 1999, August 1999, and November 1999 revealed little modification of the July, 1996 sliding rock configuration. Only four rocks were repositioned during the El Nino winter of 1997-1998, suggesting that activity may not be restricted to winter storms. (C) 2000 Elsevier Science B.V. All rights reserved.

  3. A novel no-insulation winding technique of high temperature-superconducting racetrack coil for rotating applications: A progress report in Korea university. (United States)

    Choi, Y H; Song, J B; Yang, D G; Kim, Y G; Hahn, S; Lee, H G


    This paper presents our recent progress on core technology development for a megawatt-class superconducting wind turbine generator supported by the international collaborative R&D program of the Korea Institute of Energy Technology Evaluation and Planning. To outperform the current high-temperature-superconducting (HTS) magnet technology in the wind turbine industry, a novel no-insulation winding technique was first proposed to develop the second-generation HTS racetrack coil for rotating applications. Here, we briefly report our recent studies on no-insulation (NI) winding technique for GdBCO coated conductor racetrack coils in the following areas: (1) Charging-discharging characteristics of no-insulation GdBCO racetrack coils with respect to external pressures applied to straight sections; (2) thermal and electrical stabilities of no-insulation GdBCO racetrack coils encapsulated with various impregnating materials; (3) quench behaviors of no-insulation racetrack coils wound with GdBCO conductor possessing various lamination layers; (4) electromagnetic characteristics of no-insulation GdBCO racetrack coils under time-varying field conditions. Test results confirmed that this novel NI winding technique was highly promising. It could provide development of a compact, mechanically dense, and self-protecting GdBCO magnet for use in real-world superconducting wind turbine generators.

  4. Reduction of Thoroughbred racing fatalities at New York Racing Association racetracks using a multi-disciplinary mortality review process. (United States)

    Palmer, Scott E; McDonough, Sean P; Mohammed, Hussni O


    Between January 1, 2013 and December 31, 2015, findings of a New York State Gaming Commission-Cornell University postmortem examination program were utilized in a multi-disciplinary mortality review process to review 129 racing fatalities at Thoroughbred racetracks operated by the New York Racing Association (NYRA). Musculoskeletal fractures comprised 79% of the fatalities; cardiopulmonary conditions accounted for 12% of the fatalities. Other causes of death included gastrointestinal (3%), respiratory (5%), and central nervous system (2%) conditions. Fetlock failure represented 50% of the musculoskeletal fatalities. The general distribution of these findings was very similar to that reported by the California Animal Health and Food Safety Laboratory System during the same period. These findings, used in conjunction with a comprehensive mortality review process and regulatory reform, have contributed to a significant reduction of the incidence of Thoroughbred racing fatalities at NYRA racetracks during the period of this review.

  5. Component Ratios of Independent and Herding Betters in a Racetrack Betting Market

    CERN Document Server

    Mori, Shintaro


    We study the time series data of the racetrack betting market in the Japan Racing Association (JRA). As the number of votes t increases, the win bet fraction x(t) converges to the final win bet fraction x_{f}. We observe the power law $(x(t)-x_{f})^{2} \\propto t^{-\\beta}$ with $\\beta\\simeq 0.488$. We measure the degree of the completeness of the ordering of the horses using an index AR, the horses are ranked according to the size of the win bet fraction. AR(t) also obeys the power law and behaves as $\\mbox{AR}_{f}-\\mbox{AR}(t)\\propto t^{-\\gamma}$ with $\\gamma\\simeq 0.589$, where AR_{f} is the final value of AR. We introduce a simple voting model with two types of voters-independent and herding. Independent voters provide information about the winning probability of the horses and herding voters decide their votes based on the popularities of the horses.This model can explain two power laws of the betting process. The component ratio of the independent voter to the herding voter is 1:3.

  6. Distributed CAN-bus Based Beam Diagnostic System for Pulse Race-Track Microtron (United States)

    Chepurnov, Alexander

    Very compact 70 MeV pulse race-track microtron is under construction now. To acquire outputs of beam-current transformers on every orbit and pulses of high voltage and RF field a distributed multi-channel beam diagnostic system was developed. Each acquisition controller consists of four fast differential amplifiers and one DSP-based micro-controller with on-chip ADC and CAN-bus controller. Each amplifier is coupled with beam-current transformer and has bandwidth of up to 150MHz and gain of up to 10. One of four channels is acquired during a measurement cycle. Another channel could be selected between two following pulses. All the controllers are connected via optically coupled CAN-bus with a host diskless PC running under Linux with the RTLinux extension. Dedicated software of the system consists of low level acquisition software for DSP, network software for controllers and host PC, application software for PC to present date for operator and control system. Standard CAN application layers were considered but refused because of the closed character of the whole system and centralised synchronisation of the whole system. Dedicated software of the system consists from low level acquisition software for DSP, network software for controllers and host PC, application software for PC to present date for operator and control system. Standard CAN application layers were considered but refused because of closed character of the whole system and centralised synchronisation of the whole system.

  7. Incorporation of Mean/Maximum Stress Effects in the Multiaxial Racetrack Filter

    Directory of Open Access Journals (Sweden)

    Marco Antonio Meggiolaro


    Full Text Available This work extends the Multiaxial Racetrack Filter (MRF to incorporate mean or maximum stress effects, adopting a filter amplitude that depends on the current stress level along the stress or strain path. In this way, a small stress or strain amplitude event can be filtered out if associated with a non-damaging low mean or peak stress level, while another event with the very same amplitude can be preserved if happening under a more damaging high mean or peak stress level. The variable value of the filter amplitude must be calculated in real time, thus it cannot depend on the peak or mean stresses along a load event, because it would require cycle identification and as so information about future events. Instead, mean/maximum stress effects are modeled in the filter as a function of the current (instantaneous hydrostatic or normal stress along the multiaxial load path, respectively for invariantbased and critical-plane models. The MRF efficiency is evaluated from tension-torsion experiments in 316L stainless steel tubular specimens under non-proportional (NP load paths, showing it can robustly filter out nondamaging events even under multiaxial NP variable amplitude loading histories

  8. Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

    Directory of Open Access Journals (Sweden)

    Richard D Norris

    Full Text Available The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

  9. Performance of the BATMAN RF source with a large racetrack shaped driver (United States)

    Kraus, W.; Schiesko, L.; Wimmer, C.; Fantz, U.; Heinemann, B.


    In the negative ion sources in neutral beam injection systems (NBI) of future fusion reactors the plasma is generated in up to eight cylindrical RF sources ("drivers") from which it expands into the main volume. For these large sources, in particular those used in the future DEMO NBI, a high RF efficiency and operational reliability is required. To achieve this it could be favorable to substitute each pair of drivers by one larger one. To investigate this option the cylindrical driver of the BATMAN source at IPP Garching has been replaced by a large source with a racetrack shaped base area and tested using the same extraction system. The main differences are a five times larger source volume and another position of the Cs oven which is mounted onto the driver`s back plate and not onto the expansion volume. The conditioning characteristics and the plasma symmetry in front of the plasma grid were very similar. The extracted H- current densities jex are comparable to that achieved with the small driver at the same power. Because no saturation of jex occurred at 0.6 Pa at high power and the source allows high power operation, a maximum value 45.1 mA/cm2 at 103 kW has been reached. Sputtered Cu from the walls of the expansion volume affected the performance at low pressure, particularly in deuterium. The experiments will be therefore continued with Mo coating of all inner walls.

  10. submitter 16 T $Nb_{3}Sn$ Racetrack Model Coil Test Result

    CERN Document Server

    Perez, J C; Bajko, M; Bottura, L; Bordini, B; Chiuchiolo, A; De Rijk, G; Ferracin, P; Feuvrier, J; Grosclaude, P; Juchno, M; Rochepault, E; Rysti, J; Sarasola, X


    In the framework of the European project EuCARD, the High Field Magnet project, led by a CERN-CEA collaboration, implied the development of a large aperture $Nb_{3}Sn$ dipole magnet called FRESCA2. The magnet uses four double-pancake block-type coils, each about 1.5 m long. In order to characterize strand and cable properties, as well as to qualify the coil fabrication process, CERN started in 2012 the design and fabrication of the Racetrack Model Coil (RMC) magnet, a short model magnet using the same cable as FRESCA2 magnet with only two flat double-pancake coils about 0.8 m long. In 2013, two superconducting coils have been fabricated, making use of two different types of superconductor. In 2014 and 2015, the coils were tested both in a single and in a double-coil configuration in a support structure based on an external aluminum shell pre-loaded with water-pressurized bladders. In this paper, we describe the design of the RMC magnet and its coils, provide the main parameters of the superconductor, and repo...

  11. Mathematical Modeling Of The Acceleration Process In Race-track Microtron

    CERN Document Server

    Gromov, A M; Vasilev, A A


    The precise calculations of beam dynamics are needed to make choice of optimal design parameters of race-track microtron. As a result, the necessary physical require-ments to the accelerator systems become found. For cal-culation of the magnetic field, POISSON LANL code is used. Acceleration of the beam is investigated with the help of the program of MathCad. Nonlinear distribution of the field in magnets of micro-tron with adjustable reverse field was simulated. The equation of motion of a beam in bending magnets of re-circulation system are found and solved by a numerical method. Trajectories of the beam for all orbits in a micro-tron are received. The recursive equation for calculation of the largest area of injected beam phase and power spreads providing steady acceleration process is written. The acceleration of the beam with maximal phase-energy area through all orbits of microtron was simulated. The velocity of accelerated particles on first orbits dif-fers from velocity of light. The minimal energy ...

  12. Quench Analysis of High Current Density Nb3Sn Conductors in Racetrack Coil Configuration

    CERN Document Server

    Bajas, H; Bordini, B; Bottura, L; Izquierdo Bermudez, S; Feuvrier, J; Chiuchiolo, A; Perez, J C; Willering, G


    The luminosity upgrade of the Large Hadron Collider (HL-LHC) requires the development of new type of superconducting cables based on advanced Nb3Sn strands. In the framework of the FP7 European project EUCARD the cables foreseen for the HL-LHC project have been tested recently in a simplified racetrack coil configuration, the so-called Short Model Coil (SMC). In 2013 to 2014, two SMCs wound with 40-strand (RRP 108/127) cables, with different heat treatment processes, reached during training at 1.9 K a current and peak magnetic field of 15.9 kA, 13.9T,and 14.3 kA, 12.7 Trespectively. Using the measured signals from the voltage taps, the behavior of the quenches is analyzed in terms of transverse and longitudinal propagation velocity and hot spot temperature. These measurements are compared with both analytical and numerical calculations from adiabatic models.The coherence of the results from the presented independent methods helps in estimating the relevance of the material properties and the adiabatic assump...

  13. Trail formation by ice-shoved "sailing stones" observed at Racetrack Playa, Death Valley National Park (United States)

    Lorenz, R. D.; Norris, J. M.; Jackson, B. K.; Norris, R. D.; Chadbourne, J. W.; Ray, J.


    Trails in the usually-hard mud of Racetrack Playa in Death Valley National Park attest to the seemingly-improbable movement of massive rocks on an exceptionally flat surface. The movement of these rocks, previously described as "sliding stones", "playa scrapers", "sailing stones" etc., has been the subject of speculation for almost a century but is an exceptionally rare phenomenon and until now has not been directly observed. Here we report documentation of multiple rock movement and trail formation events in the winter of 2013-2014 by in situ observation, video, timelapse cameras, a dedicated meteorological station and GPS tracking of instrumented rocks. Movement involved dozens of rocks, forming fresh trails typically of 10s of meters length at speeds of ~5 cm s-1 and were caused by wind stress on a transient thin layer of floating ice. Fracture and local thinning of the ice decouples some rocks from the ice movement, such that only a subset of rocks move in a given event.

  14. Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application (United States)

    Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi


    The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40-50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

  15. Using the integral equations method to model a 2G racetrack coil with anisotropic critical current dependence (United States)

    Martins, F. G. R.; Sass, F.; Barusco, P.; Ferreira, A. C.; de Andrade, R., Jr.


    Second-generation (2G) superconducting wires have already proved their potential in several applications. These materials have a highly nonlinear behavior that turns an optimized engineering project into a challenge. Between several numerical techniques that can be used to perform this task, the integral equations (IE) method stands out for avoiding mesh problems by representing the 2G wire cross-sectional area by a line. While most applications need to be represented in a 3D geometry, the IE is limited to longitudinal or axisymmetric models. This work demonstrates that a complex 3D geometry can be modeled by several coupled simulations using the IE method. In order to prove this statement, the proposed technique was used to simulate a 2G racetrack coil considering the self-field magnitude (B) and incidence angle (θ) on the tape. The J c characteristic was modeled in terms of parallel and normal to the tape plane magnetic field components (J c(B ∥ , B ⊥)) obtained from a V–I(B, θ) characterization of a tape segment. This result was implemented using commercial software with both A–V (vector magnetic potential and scalar voltage potential) and IE coupled simulations solved by finite elements. This solution bypasses the meshing problem due to the tapes slim geometry, considering each turn a single 1D model, all magnetically interacting in two 2D models. The simulations results are in good agreement to what was both expected and observed in the literature. The simulation is compared to the measured V–I characteristic for a single pancake racetrack coil built with same geometry as its simulation models, and a theoretical study demonstrates the possibilities of the proposed tool for analyzing a racetrack coil current density and electric field behavior in each of its turns.

  16. Dynamic testing of horseshoe designs at impact on synthetic and dirt Thoroughbred racetrack materials. (United States)

    Mahaffey, C A; Peterson, M L; Thomason, J J; McIlwraith, C W


    Different horseshoe designs have been developed in an attempt to optimise footing for equine athletes. Horseshoe performance is assumed to be dependent on the surface and gait, but there are limited data on horseshoe performance on different surfaces, independent of gait variation. To quantify the dynamic loading for 3 aluminium racing shoe designs on Thoroughbred racetrack surface materials, using a biomechanical surface tester. A flat racing plate, a serrated V-Grip and a shoe with a 6 mm toe grab and 10 mm heel calks were tested on synthetic and dirt surfaces under typical operating conditions of temperature and moisture content for the respective material samples. Samples were tested under laboratory conditions, replicating a track surface by compacting material into a latex-lined mould surrounded by silica sand for representative boundary conditions. Peak loading and loading rates were measured vertically and horizontally (craniocaudal), simulating aspects of primary and secondary impacts of the hoof in a galloping horse. Maximum vertical and shear loads and loading rates were not significantly different between shoe types, with the exception of a reduced craniocaudal loading rate for the V-Grip shoe on the synthetic surface. All other statistical significance was related to the surface material. These 3 different Thoroughbred racing shoes do not have a significant impact on loading and loading rate, with the exception of the V-Grip shoe on a synthetic surface. Although the V-Grip may reduce craniocaudal peak load rates in a synthetic material with relatively high wax and/or low oil content, the reduction in load rate is less than the difference found between materials. This study indicates that shoeing has little effect, and that a track's surface material and its preparation have a significant effect on the dynamic loading during the impact phase of the stance. © 2015 EVJ Ltd.

  17. A comparative study of MOEM pressure sensors using MZI, DC, and racetrack resonator IO structures (United States)

    Selvarajan, A.; Pattnaik, Prasant Kumar; Badrinarayana, T.; Srinivas, T.


    In recent years micro-electro-mechanical system (MEMS) sensors have drawn considerable attention due to their attraction in terms of miniaturization, batch fabrication and ease of integration with the required electronics circuitry. Micro-opto-electro-mechanical (MOEM) devices and systems, based on the principles of integrated optics and micromachining technology on silicon have immense potential for sensor applications. Employing optical techniques have important advantages such as functionality, large bandwidth and higher sensitivity. Pressure sensing is currently the most lucrative market for solid-state micro sensors. Pressure sensing using micromachined structures utilize the changes induced in either the resistive or capacitive properties of the electro-mechanical structure by the impressed pressure. Integrated optical pressure sensors can utilize the changes to the amplitude, phase, refractive index profile, optical path length, or polarization of the lightwave by the external pressure. In this paper we compare the performance characteristics of three types of MOEM pressure sensors based on Mach-Zehnder Interferometer (MZI), Directional Coupler (DC) and racetrack resonator (RR) integrated optical geometries. The first two configurations measure the pressure changes through a change in optical intensity while the third one measures the same in terms of frequency or wavelength change. The analysis of each sensors has been carried out in terms of mechanical and optical models and their interrelationship through optomechanical coupling. For a typical diaphragm of size 2mm × 1mm × 20 μm, normalized pressure sensitivity of 18.35 μW/mW/kPa, 29.37 μW/mW/kPa and 2.26 pm/kPa in case of MZI, DC and RR devices have been obtained respectively. The noise performance of these devices are also presented.

  18. The Effects of Reading Racetrack with Direct Instruction Flashcards and a Token System on Sight Word Acquisition for Two Primary Students with Severe Conduct Disorders (United States)

    Hopewell, Kim; McLaughlin, T. F.; Derby, K. Mark


    Introduction: The purpose of the study was to evaluate the effectiveness of reading racetracks and direct instruction flashcards with two students with behavior disorders. A token economy with a response cost component was also implemented to increase on-task behavior during data collection. Method: The participants were two eight-year-old males.…

  19. The Effects of Direct Instruction Flashcard and Math Racetrack Procedures on Mastery of Basic Multiplication Facts by Three Elementary School Students (United States)

    Skarr, Adam; Zielinski, Katie; Ruwe, Kellen; Sharp, Hannah; Williams, Randy L.; McLaughlin, T. F.


    The purpose of this study was to determine if a typical third-grade boy and fifth-grade girl and a boy with learning disabilities could benefit from the combined use of Direct Instruction (DI) flashcard and math racetrack procedures in an after-school program. The dependent variable was accuracy and fluency of saying basic multiplication facts. A…

  20. Lasers. (United States)

    Passeron, T


    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  1. [Lasers]. (United States)

    Passeron, T


    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  2. A tunable single-monochromator Raman system based on the supercontinuum laser and tunable filters for resonant Raman profile measurements (United States)

    Liu, X.-L.; Liu, H.-N.; Tan, P.-H.


    Resonant Raman spectroscopy requires that the wavelength of the laser used is close to that of an electronic transition. A tunable laser source and a triple spectrometer are usually necessary for resonant Raman profile measurements. However, such a system is complex with low signal throughput, which limits its wide application by scientific community. Here, a tunable micro-Raman spectroscopy system based on the supercontinuum laser, transmission grating, tunable filters, and single-stage spectrometer is introduced to measure the resonant Raman profile. The supercontinuum laser in combination with transmission grating makes a tunable excitation source with a bandwidth of sub-nanometer. Such a system exhibits continuous excitation tunability and high signal throughput. Its good performance and flexible tunability are verified by resonant Raman profile measurement of twisted bilayer graphene, which demonstrates its potential application prospect for resonant Raman spectroscopy.

  3. A tunable single-monochromator Raman system based on the supercontinuum laser and tunable filters for resonant Raman profile measurements. (United States)

    Liu, X-L; Liu, H-N; Tan, P-H


    Resonant Raman spectroscopy requires that the wavelength of the laser used is close to that of an electronic transition. A tunable laser source and a triple spectrometer are usually necessary for resonant Raman profile measurements. However, such a system is complex with low signal throughput, which limits its wide application by scientific community. Here, a tunable micro-Raman spectroscopy system based on the supercontinuum laser, transmission grating, tunable filters, and single-stage spectrometer is introduced to measure the resonant Raman profile. The supercontinuum laser in combination with transmission grating makes a tunable excitation source with a bandwidth of sub-nanometer. Such a system exhibits continuous excitation tunability and high signal throughput. Its good performance and flexible tunability are verified by resonant Raman profile measurement of twisted bilayer graphene, which demonstrates its potential application prospect for resonant Raman spectroscopy.

  4. Proposal for a race-track microtron with high peak current

    NARCIS (Netherlands)

    Ernst, G.J.; Haselhoff, E.H.; Witteman, W.J.; Botman, J.I.M.; van Genderen, W.; Hagedoorn, H.L.; van der Heide, J.A.; Kleeven, W.J.G.M.


    In order to obtain high gain in a free electron laser a high-quality electron beam with high peak current is required. It is well-known that a microtron is able to produce a high-quality beam having low emittance and small energy spread (1%). Because a circular microtron has a limited high-current

  5. Physical and Visual Accessibilities in Intensive Care Units: A Comparative Study of Open-Plan and Racetrack Units. (United States)

    Rashid, Mahbub; Khan, Nayma; Jones, Belinda


    This study compared physical and visual accessibilities and their associations with staff perception and interaction behaviors in 2 intensive care units (ICUs) with open-plan and racetrack layouts. For the study, physical and visual accessibilities were measured using the spatial analysis techniques of Space Syntax. Data on staff perception were collected from 81 clinicians using a questionnaire survey. The locations of 2233 interactions, and the location and length of another 339 interactions in these units were collected using systematic field observation techniques. According to the study, physical and visual accessibilities were different in the 2 ICUs, and clinicians' primary workspaces were physically and visually more accessible in the open-plan ICU. Physical and visual accessibilities affected how well clinicians' knew their peers and where their peers were located in these units. Physical and visual accessibilities also affected clinicians' perception of interaction and communication and of teamwork and collaboration in these units. Additionally, physical and visual accessibilities showed significant positive associations with interaction behaviors in these units, with the open-plan ICU showing stronger associations. However, physical accessibilities were less important than visual accessibilities in relation to interaction behaviors in these ICUs. The implications of these findings for ICU design are discussed.

  6. Laser-based dynamic evaporation and surface shaping of fused silica with assist gases: a path to rimless laser machining (United States)

    Elhadj, S.; Matthews, M. J.; Guss, G. M.; Bass, I. L.


    Evaporation and ablation are fundamental processes which drive laser-material processing performance. In applications where surface shape is important, control of the temperature field and the resulting spatially varying material response must be considered. For that purpose, assist gases are useful in, first, lowering treatment temperatures and, second, in changing interfacial and bulk chemistry to limit capillary-driven flow. Additionally, laser-matter coupling is influenced by pulse length as it determines the heat affected zone. Using infrared imaging of CO2 laser-heated fused silica and surface profile measurements, we derive temperature and time dependent pitting rates along with shapes for a range of gases that include hydrogen, nitrogen, air, and helium. In the range of 1,500-4,500 K, evaporation, flow, and densification are shown to contribute to the pit shape. Analysis reveals a strong and complex dependence of rim formation on heating time and gas chemistry, mostly by lowering treatment temperature. Under dynamic heating, chemicapillarity appears to help in lowering rim height, in spite of the reactants mass transport limitations. Results on this gas-assisted approach suggest the possibility for sub-nanometer "rimless" laser-based machining.

  7. The effects of using flashcards with reading racetrack to teach letter sounds, sight words, and math facts to elementary students with learning disabilities

    Directory of Open Access Journals (Sweden)

    Rachel Erbey


    Full Text Available The purpose of this study was to measure the effects of reading racetrack and flashcards when teaching phonics, sight words, and addition facts. The participants for the sight word and phonics portion of this study were two seven-year-old boys in the second grade. Both participants were diagnosed with a learning disability. The third participant was diagnosed with attention deficit hyperactivity disorder by his pediatrician and with a learning disability and traumatic brain injury by his school’s multi-disciplinary team.. The dependent measures were corrects and errors when reading from a first grade level sight word list. Math facts were selected based on a 100 add fact test for the third participant. The study demonstrated that racetracks paired with the flashcard intervention improved the students’ number of corrects for each subject-matter area (phonics, sight words, and math facts. However, the results show that some students had more success with it than others. These outcomes clearly warrant further research.

  8. Effects of Optical Dopants and Laser Wavelength on Atom Probe Tomography Analyses of Borosilicate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaonan; Schreiber, Daniel K.; Neeway, James J.; Ryan, Joseph V.; Du, Jincheng


    Atom probe tomography (APT) is a novel analytical microscopy method that provides three dimensional elemental mapping with sub-nanometer spatial resolution and has only recently been applied to insulating glass and ceramic samples. In this paper, we have studied the influence of the optical absorption in glass samples on APT characterization by introducing different transition metal optical dopants to a model borosilicate nuclear waste glass (international simple glass). A systematic comparison is presented of the glass optical properties and the resulting APT data quality in terms of compositional accuracy and the mass spectra quality for two APT systems: one with a green laser (532 nm, LEAP 3000X HR) and one with a UV laser (355 nm, LEAP 4000X HR). These data were also compared to the study of a more complex borosilicate glass (SON68). The results show that the analysis data quality such as compositional accuracy and total ions collected, was clearly linked to optical absorption when using a green laser, while for the UV laser optical doping aided in improving data yield but did not have a significant effect on compositional accuracy. Comparisons of data between the LEAP systems suggest that the smaller laser spot size of the LEAP 4000X HR played a more critical role for optimum performance than the optical dopants themselves. The smaller spot size resulted in more accurate composition measurements due to a reduced background level independent of the material’s optical properties.


    Directory of Open Access Journals (Sweden)

    W. David Lewis


    Full Text Available Edward V. (Eddie Rickenbacker (1890-1973 is best remembered for hisrecord as a combat pilot in World War I, in which he shot down 26 Germa naircraft and won fame as America’s "Ace of Aces." From 1934 until 1963 he was general manager, president, and board chairman of Eastern Air Lines, which was for a time the most profitable air carrier in the United States. This paper shows how Rickenbacker’s fiercely entrepreneurial style of management was born in his early involvement in the automobile industry, and particularly in his career as an automobile racing driver from 1909 through 1916.

  10. Frequency of and risk factors associated with catastrophic musculoskeletal injuries in Quarter Horses at two Midwestern racetracks: 67 cases (2000-2011). (United States)

    Beisser, Andrea; McClure, Scott; Rezabek, Grant; Soring, Keith H; Wang, Chong


    To determine the incidence and anatomic location of and potential risk factors for catastrophic musculoskeletal injuries (CMIs) in racing Quarter Horses. Retrospective matched case-control study. 67 racing Quarter Horse racehorses euthanized because of CMIs and 134 matched controls. Data for Quarter Horses that sustained CMIs and the total number of race starts for each year were obtained from 2 Midwestern racing jurisdictions from 2000 through 2011. Information for each horse with a CMI and for 2 randomly selected control horses that ran in the same race but did not incur a CMI were obtained from race records, past performance reports, and video analysis. There were 61,797 race starts and 82 CMIs from 2000 through 2011 at the 2 racetracks studied, for an overall CMI incidence of 1.33 CMIs/1,000 starts. Sixty-seven horses with CMIs for which complete data were available and 134 matched control horses were included in the study. There was no difference in the incidence of CMIs between the 2 racetracks or over the years studied. The right forelimb was injured in 38 of the 67 (56.7%) horses. Injures to the carpus (24/67 [35.8%]) and metacarpophalangeal joint (fetlock joint; 23/67 [34.3%]) occurred most frequently. Case-control data indicated that the horses with a CMI had fewer starts, were more likely to have stumbled at the break, had a more erratic stride, were fatigued, and trailed in the race, compared with matched controls from the same races. Irrespective of race distance, most of the horses (47/67 [70.1%]) were injured after or within 10 yards before the finish line. The results of the present study may aid in the identification of racing Quarter Horses at risk for CMIs. The cluster of injuries near the finish line provides a specific focus for future research into methods of injury prevention in this population of racehorses.

  11. On-Chip Diamond Raman Laser

    CERN Document Server

    Latawiec, Pawel; Burek, Michael J; Hausmann, Birgit J M; Bulu, Irfan; Loncar, Marko


    Synthetic single-crystal diamond has recently emerged as a promising platform for Raman lasers at exotic wavelengths due to its giant Raman shift, large transparency window and excellent thermal properties yielding a greatly enhanced figure-of-merit compared to conventional materials. To date, diamond Raman lasers have been realized using bulk plates placed inside macroscopic cavities, requiring careful alignment and resulting in high threshold powers (~W-kW). Here we demonstrate an on-chip Raman laser based on fully-integrated, high quality-factor, diamond racetrack micro-resonators embedded in silica. Pumping at telecom wavelengths, we show Stokes output discretely tunable over a ~100nm bandwidth around 2-{\\mu}m with output powers >250 {\\mu}W, extending the functionality of diamond Raman lasers to an interesting wavelength range at the edge of the mid-infrared spectrum. Continuous-wave operation with only ~85 mW pump threshold power in the feeding waveguide is demonstrated along with continuous, mode-hop-fr...

  12. Molecular Electronics at Metal/Semiconductor Junctions. Si Inversion by Sub-Nanometer Molecular Films

    NARCIS (Netherlands)

    Yaffe, O.; Scheres, L.M.W.; Reddy Puniredd, S.; Stein, N.; Biller, A.; Har Lavan, R.; Shpaisman, H.; Zuilhof, H.; Haick, H.; Cahen, D.; Vilan, A.


    Electronic transport across n-Si-alkyl monolayer/Hg junctions is, at reverse and low forward bias, independent of alkyl chain length from 18 down to 1 or 2 carbons! This and further recent results indicate that electron transport is minority, rather than majority carrier dominated, occurs via

  13. Sub-nanometer stable precision MEMS clamping mechanism maintaining clamp force unpowered for TEM application

    NARCIS (Netherlands)

    Brouwer, Dannis Michel; de Jong, B.R.; Soemers, Herman; van Dijk, Johannes


    A design is presented for a relatively large force (0.5 mN) high-precision MEMS clamping mechanism. The clamp is a part of a MEMS transmission electron microscope (TEM) sample manipulator, which needs to be fixed unpowered once positioned. The elastic deformation of the clamp suspension has been

  14. Imaging a pore network in a clay-rock at the sub-nanometer scale


    Gaboreau, Stéphane; Pret², D; Tournassat, Christophe


    International audience; Mini-Symposium Description (2.22) Clayey rocks properties are the focus of an ever-increasing interest from the geoscience community. These fine-grained sedimentary rocks (mudstone, argillite, shalesetc.) are recognized as key-components for energy-related technologies, for which they could serve as isolation material (in radioactive waste disposal), caprocks (in CO 2 capture and storage systems), or as reservoir rocks for hydrocarbons (gas and oil shales) (Bourg, 2015...

  15. Supported sub-nanometer Ta oxide clusters as model catalysts for the selective epoxidation of cyclooctene

    KAUST Repository

    Zwaschka, Gregor


    The preparation of organic ligands-free, isolated tantalum oxide atoms (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting surface complexes were thoroughly characterized and tested as supported catalysts for the epoxidation of cycloalkenes. The observed catalytic performance highlights the potential of the applied method for the production of active catalysts and the study of well-defined, ligand-free metal oxide moieties.

  16. Phase-shifted real-time laser feedback interferometry (United States)

    Ovryn, Ben; Andrews, James H.; Eppell, Steven J.; Khaydarov, John D.


    We have combined the principles of phase-shifting interferometry (PSI) and laser-feedback interferometry (LFI) to produce a new instrument that can measure both optical path length (OPL) changes and discern sample reflectivity variations. In LFI, coherent feedback of the incident light either reflected directly from a surface or reflected after transmission through a region of interest will modulate the output intensity of the laser. LFI can yield a high signal-to-noise ratio over a broad range of sample reflectance. By combining PSI and LFI, we have produced a robust instrument, based upon a HeNe laser, with high dynamic range that can be used to measure either static (dc) or oscillatory changes along the optical path. As with other forms of interferometry, large changes in OPL require phase unwrapping. Conversely, small phase changes are limited by the fraction of a fringe that can be measured. We introduce the phase shifts with an electro-optic modulator (EOM) and use either the Cane or Hariharan algorithms to determine the phase and visibility. We have determined the accuracy and precision of our technique by measuring both the bending of a cantilevered piezoelectric bimorph and linear ramps to the EOM. Using PSI, sub-nanometer displacements can be measured and, as with other forms of PSI, there is no sign ambiguity to the displacement measurement. We have also analyzed the behavior ofthe interferometer for both low and high reflectivity samples. Since the change in the laser's intensity is a non-linear function of the reflected amplitude, additional measures are required before applying PSI methods to high reflectivity samples.

  17. Application of Phase Shifted, Laser Feedback Interferometry to Fluid Physics (United States)

    Ovryn, Ben; Eppell, Steven J.; Andrews, James H.; Khaydarov, John


    We have combined the principles of phase-shifting interferometry (PSI) and laser-feedback interferometry (LFI) to produce a new instrument that can measure both optical path length (OPL) changes and discern sample reflectivity variations. In LFI, coherent feedback of the incident light either reflected directly from a surface or reflected after transmission through a region of interest will modulate the output intensity of the laser. LFI can yield a high signal-to-noise ratio even for low reflectivity samples. By combining PSI and LFI, we have produced a robust instrument, based upon a HeNe laser, with high dynamic range that can be used to measure either static (dc) or oscillatory changes along the optical path. As with other forms of interferometry, large changes in OPL require phase unwrapping. Conversely, small phase changes are limited by the fraction of a fringe that can be measured. We introduce the phase shifts with an electro-optic modulator (EOM) and use either the Carre or Hariharan algorithms to determine the phase and visibility. We have determined the accuracy and precision of our technique by measuring both the bending of a cantilevered piezoelectric bimorph and linear ramps to the EOM. Using PSI, sub-nanometer displacements can be measured. We have combined our interferometer with a commercial microscope and scanning piezoelectric stage and have measured the variation in OPL and visibility for drops of PDMS (silicone oil) on coated single crystal silicon. Our measurement of the static contact angle agrees with the value of 68 deg stated in the literature.

  18. Archaean Au-Ag mineralisation at Racetrack, near Kalgoorlie, Western Australia: a high crustal-level expression of the Archaean composite lode-gold system (United States)

    Gebre-Mariam, M.; Groves, D. I.; McNaughton, N. J.; Mikucki, E. J.; Vearncombe, J. R.


    The Racetrack Au-Ag deposit, in the Archaean Yilgarn Block, Western Australia, is hosted by a porphyritic basalt in a low greenschist facies setting and is associated with a brittle strike-slip fault system. Three distinct and successive stages of hydrothermal activity and late quartz-carbonate veining resulted in multiple veining and/or brecciation: Stages I and II are Au-bearing, whereas Stage III and late veins are barren. The ore shows features of both classic epithermal and mesothermal deposits. Alteration assemblages, typified by sericitization, carbonization, silicification and chloritization, are similar to those of mesothermal gold deposits, wheras the quartz vein-textures including comb, rosette, plumose and banded, ore mineralogyof arsenopyrite, pyrite, chalcopyrite, sphalerite, galena, freibergite, tetrahedrite, tennantite, fahlore, electrum and gold, and metal associations (Cu, As, Ag, Sn, Sb, W, Au and Pb) are more characteristics of epithermal deposits. Fluid inclusions related to Stage II are two phase and aqueous with 1-8 (average 4) wt. % NaCl equiv. and CO2 content of <0.85 molal. Pressure-corrected homogenisation temperatures range from 190°C to 260°C. Mineral assemblages indicate that ore fluid pH ranged between 4.2 and 5.3, fO 2 between 10-38.8 and 10-39.6 bars, and mΣs between 10-3.2 and 10-3.6. Calculated chemical and stable isotope compositions require a component of surface water in the ore fluid depositing the mineralisation, but evidence for deep crustal Pb indicates that deeply sourced fluids were also involved. The deposit is interpreted to have formed in a shallow environment via mixing of deeply sourced fluids, from at least as deep as the base of the greenstone belt, with surface waters. It therefore represents the upper crustal end-member of the crustal depth spectrum of Archaean lode-gold mineralisation.

  19. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)



    The Lasers Technology Program of IPEN is committed to the development of new lasers based on the research of optical materials and new technologies, as well to laser applications in several areas: Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. The Program is basically divided into two main areas: Material and Laser Development and Laser Applications.

  20. Laser principles. (United States)

    Bogdan Allemann, Inja; Kaufman, Joely


    Since the construction of the first laser in the 1960s, the role that lasers play in various medical specialities, including dermatology, has steadily increased. However, within the last 2 decades, the technological advances and the use of lasers in the field of dermatology have virtually exploded. Many treatments have only become possible with the use of lasers. Especially in aesthetic medicine, lasers are an essential tool in the treatment armamentarium. Due to better research and understanding of the physics of light and skin, there is now a wide and increasing array of different lasers and devices to choose from. The proper laser selection for each indication and treatment requires a profound understanding of laser physics and the basic laser principles. Understanding these principles will allow the laser operator to obtain better results and help avoid complications. This chapter will give an in-depth overview of the physical principles relevant in cutaneous laser surgery. Copyright © 2011 S. Karger AG, Basel.

  1. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)



    The Laser Technology Program of IPEN is developed by the Center for Lasers and Applications (CLA) and is committed to the development of new lasers based on the research of new optical materials and new resonator technologies. Laser applications and research occur within several areas such as Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. Additional goals of the Program are human resource development and innovation, in association with Brazilian Universities and commercial partners.

  2. Laser handbook

    CERN Document Server

    Bass, Michael


    Volume 4 of the Laser Handbook continues the high standard set by the first three volumes which were widely acclaimed by numerous reviewers in Science, Optical Spectra and Laser Technology, as presenting an outstanding contribution to the field of laser technology.

  3. Microchip Lasers (United States)


    USA E-mail: Abstract Microchip lasers are a rich family of solid-state lasers defined by their small size, robust integration...reliability, and potential for low-cost mass production. Continuous-wave microchip lasers cover a wide range of wavelengths, often operate single

  4. Lasers (Rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal


    A laser is an instrument that produces an enormously intense pencil-thin beam of light. In this booklet we shall learn what there is about the laser that gives it so much promise. We shall investigate what it is, how it works, and the different kinds of lasers there are.

  5. In Situ Synchrotron X-Ray Diffraction and Small Angle X-Ray Scattering Studies on Rapidly Heated and Cooled Ti-Al and Al-Cu-Mg Alloys Using Laser-Based Heating (United States)

    Kenel, C.; Schloth, P.; Van Petegem, S.; Fife, J. L.; Grolimund, D.; Menzel, A.; Van Swygenhoven, H.; Leinenbach, C.


    Beam-based additive manufacturing (AM) typically involves high cooling rates in a range of 103-104 K/s. Therefore, new techniques are required to understand the non-equilibrium evolution of materials at appropriate time scales. Most technical alloys have not been optimized for such rapid solidification, and microstructural, phase, and elemental solubility behavior can be very different. In this work, the combination of complementary in situ synchrotron micro-x-ray diffraction (microXRD) and small angle x-ray scattering (SAXS) studies with laser-based heating and rapid cooling is presented as an approach to study alloy behavior under processing conditions similar to AM techniques. In rapidly solidified Ti-48Al, the full solidification and phase transformation sequences are observed using microXRD with high temporal resolution. The high cooling rates are achieved by fast heat extraction. Further, the temperature- and cooling rate-dependent precipitation of sub-nanometer clusters in an Al-Cu-Mg alloy can be studied by SAXS. The sensitivity of SAXS on the length scales of the newly formed phases allows their size and fraction to be determined. These techniques are unique tools to help provide a deeper understanding of underlying alloy behavior and its influence on resulting microstructures and properties after AM. Their availability to materials scientists is crucial for both in-depth investigations of novel alloys and also future production of high-quality parts using AM.

  6. Laser photocoagulation - eye (United States)

    Laser coagulation; Laser eye surgery; Photocoagulation; Laser photocoagulation - diabetic eye disease; Laser photocoagulation - diabetic retinopathy; Focal photocoagulation; Scatter (or pan retinal) photocoagulation; Proliferative ...

  7. Nonreciprocal lasing and polarization selectivity in silicon ring Raman lasers based on micro- and nano-scale waveguides (United States)

    Vermeulen, N.


    In this paper I present a generic model that describes the lasing characteristics of continuous-wave circular and racetrack-shaped ring Raman lasers based on micro- and nano-scale silicon waveguides, including their lasing directionality and polarization behavior. This model explicitly takes into account the effective Raman gain values for forward and backward lasing, the Raman amplification in the bus waveguide, and the spatial gain variations for different polarization states in the ring structure. I show numerically that ring lasers based on micro-scale waveguides generate unidirectional lasing in either the forward or backward direction because of an asymmetry in nonlinear losses at near-infrared telecommunication wavelengths, whereas those based on nanowires yield only backward lasing due to a non-reciprocity in effective gain. Furthermore, the model indicates that backward lasing can yield a significantly higher lasing output at the bus waveguide facets than lasing in the forward direction. Finally, considering a TE-polarized pump input for a (100) grown silicon ring Raman laser, I demonstrate numerically that the polarization state of the lasing radiation strongly depends on whether micro-scale or nano-scale waveguides are used.

  8. Biocavity Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Gourley, P.L.; Gourley, M.F.


    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  9. High power lasers & systems


    Chatwin, Chris; Young, Rupert; Birch, Philip


    Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

  10. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)



    The Lasers Technology Program of IPEN is strongly committed to the study of Laser Applications on several areas: Nuclear, Medicine and Dentistry, Industry, Environment and Advanced research, aiming not only research but diffusion and innovation in association with Brazilian universities and commercial partners.

  11. Laser device (United States)

    Scott, Jill R.; Tremblay, Paul L.


    A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

  12. Laser instrument

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, R.J.; Eagar, T.W.


    An instrument is described for intercepting a carbon dioxide incident laser beam after it has energized a desired surgical target site but before it energizes material adjacent to the surgical target site. The instrument consists of: a substrate means for transmitting energy received from a laser beam away from a surgical target site, the substrate means having a high thermal conductivity and an exterior surface; a coating means for absorbing laser energy at the wavelength of a carbon dioxide laser, the coating means covering substantially the entirety of the exterior surface of the substrate means and having a high absorptivity for energy at the wavelength of the incident laser beam; and, the coating means having thickness which is large enough to provide high absorptivity but small enough to permit absorbed energy to be readily transferred to the high conductivity substrate means, and the thickness of the coating means being not greater than 0.001 inch.

  13. High throughput laser processing

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John


    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  14. 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., 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.

  15. Laser endoscopy. (United States)

    McElvein, R B


    A carbon dioxide laser operating in the invisible infrared range (10.6 mu) generates a beam of energy that is almost completely absorbed by biological tissue with release of intense heat and rapid destruction. A laser attached to a rigid bronchoscope has been used in 18 patients ranging in age from 21 to 62 years to treat a variety of causes of airway obstruction. These include tracheal stenosis and granulation tissue (6 patients), adenoma (1), web (2), and carcinoma (9). The results were good in 15 and poor in 3 patients. However, all patients had an improved airway after laser treatment with the best results occurring in patients with benign, inflammatory disease. The advantages of the laser are a lack of bleeding, minimal edema after treatment, and minimal scar formation. The disadvantages are the expense of the machine, and the need for general anesthesia and direct visualization of the lesion.

  16. Laser Refractography

    CERN Document Server

    Rinkevichyus, B.S; Raskovskaya, I.L


    This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

  17. Il laser

    CERN Document Server

    Smith, William V


    Verso il 1960, il laser era ancora "una soluzione alla ricerca di un problema", ma fin dagli anni immediatamente successivi si è rivelato uno strumento insostituibile per le applicazioni più svariate.

  18. Green lasers

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin


    Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range......Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range...

  19. Laser weapons (United States)

    Tsipis, K.


    The potential for deploying lasers as an effective antimissile system is assessed. High intensity and precise collimation are noted as essential for lasers as weapons, although size and material properties determine the actual performance. Gas-dynamic, electron, and chemical lasers are reviewed as prime weapons candidates. Space-, ground-, and ship-based uses are considered; each demands precision pointing, involving movable mirrors, target tracking and condition sensors, and central processing for target choice, along with large capacity power generation and storage. Laser propagation in the atmosphere is degraded by absorption, scattering, thermal blooming, turbulence (causes diffraction), and plasma formation ahead of the beam. Different modes of damaging missiles are reviewed, and it is found that mirrored surfaces, ablative coatings, and fluid layers have significant abilities to protect a missile in-flight. Destroying an ICBM in the boost phase is calculated to require a one million MW generator, far beyond current power engineering capabilities. Conventional weapons are viewed as more effective than lasers, although high energy laser research may have definite applications in areas such as chemical engineering

  20. Laser therapy for cancer (United States)

    ... this page: // Laser therapy for cancer To use the sharing features on ... Lasers are also used on the skin. How Laser Therapy is Used Laser therapy can be used to: ...

  1. Laser material processing

    CERN Document Server

    Steen, William


    This text moves from the basics of laser physics to detailed treatments of all major materials processing techniques for which lasers are now essential. New chapters cover laser physics, drilling, micro- and nanomanufacturing and biomedical laser processing.

  2. Laser acceleration (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.


    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  3. Laser barometer (United States)

    Abercrombie, Kevin R.; Shiels, David; Rash, Tim


    A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.

  4. Laser Heterodyning

    CERN Document Server

    Protopopov, Vladimir V


    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  5. Laser yellowing

    Indian Academy of Sciences (India)

    References. [1] P Maravelaki-Kalaitzaki et al, Appl. Surf. Sci. 148, 92 (1999). [2] Th Skoulikidis et al, LACONA, Workshop on Lasers in Conservation of Artworks,. (1995). [3] Veronique Verges-Belmin et al, J. Cultural Heritage 4, 238s (2003). [4] V Zafiropulos et al, LACONA V Springer Proceedings in Physics 100, 313 (2003).

  6. Mirrorless lasers

    Indian Academy of Sciences (India)

    Abstract. Experimental realization of mirrorless lasers in the last decade have resulted in hectic activity in this field, due to their novelty, simplicity and ruggedness and their great potential for application. In this article, I will review the various developments in this field in roughly chronological order, and discuss some possible ...

  7. Dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Kuder, J.E.; McGinnis, J.L.; Goldberg, H.A.; Hart, T.R.; Che, T.M.


    This patent describes a dye laser. It consists of a composite composition of an inorganic oxide glass monolith with a microporous structure containing an incorporated solution comprising a solvent component and a lasable dye component. Wherein the glass monolith has sealed outer surfaces.

  8. Laser Dyes

    Indian Academy of Sciences (India)

    tions to be treated with laser radiation. They are congenital malformations consisting of superficial and deep dilated capillar- ies in the skin. The swollen blood vessels cause a reddish discol- oration of the skin. Although PWS can appear in any part of the body, they occur more often on the face and persist throughout life. N.

  9. Laser Dyes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 9. Laser Dyes. G S Shankarling K J Jarag. General Article Volume 15 Issue 9 September ... Author Affiliations. G S Shankarling1 K J Jarag1. Dyestuff Technology, Department Institute of Chemical Technology, Matunga Mumbai 400 019, India.

  10. Laser device

    DEFF Research Database (Denmark)


    The present invention provides a light source for light circuits on a silicon platform. A vertical laser cavity is formed by a gain region arranged between a first mirror structure and a second mirror structure, both acting as mirrors, by forming a grating region including an active material in a...

  11. Laser yellowing

    Indian Academy of Sciences (India)


    Nov 27, 2015 ... Author Affiliations. M B Sai Prasad1 Salvatore Siano2. Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India; CNR-IFAC, Polo Scientifico di Sesto Fiorentino, Via Madonna del Piano, 10, Sesto Fiorentino (FI)-50019, Italy ...

  12. excimer laser

    Indian Academy of Sciences (India)


    Jan 7, 2014 ... Excimer laser; krypton chloride; UV pre-ionization; gas circulation. PACS No 42.55.Lt. 1. ... active discharge volume is by spark UV radiation created adjacent to both sides of the. Figure 4. Output ... HV electrode, all along its length and spatially modulated to ensure uniform irradiation of the gas volume.

  13. Nanowire Lasers

    Directory of Open Access Journals (Sweden)

    Couteau C.


    Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  14. Excimer Laser Technology

    CERN Document Server

    Basting, Dirk


    This comprehensive survey on Excimer Lasers investigates the current range of the technology, applications and devices of this commonly used laser source, as well as the future of new technologies, such as F2 laser technology. Additional chapters on optics, devices and laser systems complete this compact handbook. A must read for laser technology students, process application researchers, engineers or anyone interested in excimer laser technology. An effective and understandable introduction to the current and future status of excimer laser technology.

  15. Laser Physics and Laser Spectroscopy. (United States)


    Introduction A basic idea for achieving short wavelength lasers is to work with multiply-ionized atoms. Such ions generally have larger energy differences... generacion , characterization and applications over the next graduate student generation. - 71- *1* . . . . . . - o - - ° ... VII. PUBLICATIONS AND

  16. RILIS laser room HD

    CERN Multimedia


    Footage of the RILIS laser room at ISOLDE. The Resonance Ionization Laser Ion Source (RILIS) is a chemically selective ion source which relies on resonant excitation of atomic transitions using tunable laser radiation. This video shows you the laser table with the different lenses and optics as well as an overview of the RILIS laser setup. It also shows laser light with different colors and operation by the RILIS laser experts. The last part of the video shows you the laser path from the RILIS laser room into the ISOLDE GPS separator room where it enters the GPS separator magnet.

  17. RILIS laser room

    CERN Multimedia


    Footage of the RILIS laser room at ISOLDE. The Resonance Ionization Laser Ion Source (RILIS) is a chemically selective ion source which relies on resonant excitation of atomic transitions using tunable laser radiation. This video shows you the laser table with the different lenses and optics as well as an overview of the RILIS laser setup. It also shows laser light with different colors and operation by the RILIS laser experts. The last part of the video shows you the laser path from the RILIS laser room into the ISOLDE GPS separator room where it enters the GPS separator magnet.

  18. Polymer Physics Prize Lecture: Self-assemblies of Giant Molecular Shape Amphiphiles as a New Platform for Engineering Structures with Sub-Nanometer Feature Sizes (United States)

    Cheng, Stephen Z. D.


    Utilizing nano-building blocks rather than atoms to construct and engineer new structures is a fresh approach to design and develop functional materials for the purpose of transferring and amplifying microscopic functionality to macroscopic materials' property. As one of the important elements of these nano-building blocks, giant molecular shape amphiphiles (GMSAs) provide a latest platform for generating self-assembled ordered structures at nanometer scale, which are stabilized by collective physical bonds (such as collective hydrogen bonding). In this talk, two topics will be focused on. First, composed of functionalized hydrophilic molecular nanoparticles as the heads with rigid shape and fixed volume, and tethered polymer chains as the tails (such as giant molecular surfactants and lipids and other topologies), these GMSAs of various architectures can self-assemble into highly diversified, thermodynamically stable microstructures at sub-10 nm length scale in the bulk, thin film and solution states. Second, GMSAs could also be constructed solely from nanoparticles interconnected via different numbers of the rigid linkages in specific symmetry, simulating the overall shapes of small molecules but with sizes that are one-order of magnitude larger in length and three-order of magnitude larger in volume. Giant crystal structures can then be obtained from this class of ``giant molecules'' via supramolecular crystallization. These findings are not only scientifically intriguing in understanding the physical principles underlying their self-assembly, but also technologically relevant in industrial applications.

  19. Elastic recoil atomic spectroscopy of light elements with sub-nanometer depth resolution; Elastische Rueckstossatomspektrometrie leichter Elemente mit Subnanometer-Tiefenaufloesung

    Energy Technology Data Exchange (ETDEWEB)

    Kosmata, Marcel


    In this thesis the QQDS magnetic spectrometer that is used for high resolution ion beam analysis (IBA) of light elements at the Helmholtz-Zentrum Dresden-Rossendorf is presented for the first time. In addition all parameters are investigated that influence the analysis. Methods and models are presented with which the effects can be minimised or calculated. There are five focal points of this thesis. The first point is the construction and commissioning of the QQDS magnetic spectrometer, the corresponding scattering chamber with all the peripherals and the detector, which is specially developed for high resolution elastic recoil detection. Both the reconstructed spectrometer and the detector were adapted to the specific experimental conditions needed for high-resolution Ion beam analysis of light elements and tested for routine practice. The detector consists of two components. At the back end of the detector a Bragg ionization chamber is mounted, which is used for the particle identification. At the front end, directly behind the entrance window a proportional counter is mounted. This proportional counter includes a highresistance anode. Thus, the position of the particles is determined in the detector. The following two points concern fundamental studies of ion-solid interaction. By using a magnetic spectrometer the charge state distribution of the particles scattered from the sample after a binary collision is both possible and necessary for the analysis. For this reason the charge states are measured and compared with existing models. In addition, a model is developed that takes into account the charge state dependent energy loss. It is shown that without the application of this model the depth profiles do not correspond with the quantitative measurements by conventional IBA methods and with the thickness obtained by transmission electron microscopy. The second fundamental ion-solid interaction is the damage and the modification of the sample that occurs during heavy ion irradiation. It is shown that the used energies occur both electronic sputtering and electronically induced interface mixing. Electronic sputtering is minimised by using optimised beam parameters. For most samples the effect is below the detection limit for a fluence sufficient for the analysis. However, the influence of interface mixing is so strong that it has to be included in the analysis of the layers of the depth profiles. It is concluded from these studies that at the Rossendorf 5 MV tandem accelerator chlorine ions with an energy of 20 MeV deliver the best results. In some cases, such as the analysis of boron, the energy must be reduced to 6.5 MeV in order to retain the electronic sputtering below the detection limit. The fourth focus is the study of the influence of specific sample properties, such as surface roughness, on the shape of a measured energy spectra and respectively on the analysed depth profile. It is shown that knowledge of the roughness of a sample at the surface and at the interfaces for the analysis is needed. In addition, the contribution parameters limiting the depth resolution are calculated and compared with the conventional ion beam analysis. Finally, a comparison is made between the highresolution ion beam analysis and complementary methods published by other research groups. The fifth and last focus is the analysis of light elements in ultra thin layers. All models presented in this thesis to reduce the influence of beam damage are taken into account. The dynamic non-equilibrium charge state is also included for the quantification of elements. Depth profiling of multilayer systems is demonstrated for systems consisting of SiO{sub 2}-Si{sub 3}N{sub 4}O{sub x}-SiO{sub 2} on silicon, boron implantation profiles for ultra shallow junctions and ultra thin oxide layers, such as used as high-k materials.

  20. Lasers and medicine

    Energy Technology Data Exchange (ETDEWEB)

    Deren, Przemyslaw J. [Institute of Low Temperatures and Structure Researches, Polish Academy of Sciences, P.O.Box 1410, 50-950 Wroclaw (Poland)


    This paper presents physical bases of laser light interaction with biological tissue. Invasive and non-invasive laser applications like laser knife (scalpel), biostymulation - Low Level Laser Therapy, laser diagnosis and therapy especially Photodynamic Diagnosis and Therapy are reviewed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Advanced laser sensors


    Ebert, R.


    The paper presents the status of laser sensors based on direct and coherent detection technology. Potential and limitations of 3D- laser radar, laser vibrometer, and gated viewing systems will be described.

  2. Laser therapy (image) (United States)

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  3. Laser Research Lab (United States)

    Federal Laboratory Consortium — The Laser Research lab is thecenter for the development of new laser sources, nonlinear optical materials, frequency conversion processes and laser-based sensors for...

  4. Laser accidents: Being Prepared

    Energy Technology Data Exchange (ETDEWEB)

    Barat, K


    The goal of the Laser Safety Officer and any laser safety program is to prevent a laser accident from occurring, in particular an injury to a person's eyes. Most laser safety courses talk about laser accidents, causes, and types of injury. The purpose of this presentation is to present a plan for safety offices and users to follow in case of accident or injury from laser radiation.

  5. Laser Protection TIL (United States)

    Federal Laboratory Consortium — The Laser Protection TIL conducts research and analysis of laser protection materials along with integration schemes. The lab's objectives are to limit energy coming...

  6. Semiconductor Laser Measurements Laboratory (United States)

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  7. Laser satellite power systems

    Energy Technology Data Exchange (ETDEWEB)

    Walbridge, E.W.


    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  8. [Laser physics]. (United States)

    Banús Gassol, J M


    The commission of this article plunged me into doubt. First I should confess that I don't find excuse to escape this part if somebody wants to minimally deepen in the knowledge of the biological effects of this energy source. Secondly, when we talk about results, we use terms made and defined by Physics. Often we have polemics about results, and what really happens is that we don't reach agreements because we refer to different terms to explain the same observation; in conclusion we cannot understand each other because we do not know the adequate terms; for example, hypoxemia as oxygen deficit, which is true in an anemic patient as well as in a low oxygen saturation rate. In consequence, a good review of these concepts seems necessary to me. The third reason is the confusion that exists in our environment, I think sometimes of interest, about properties and effects of different types of laser. Only a minimal knowledge of physics will help us to state the scientific basis for understanding. The problems, nevertheless, accumulate due to the fact that the universe to which this article is directed is formed by urologists. What Physics education should we suppose they have? Superficial? Medium? Is it a collective with a uniform knowledge, being it whatever it is? The implication is clear. The article depth will depend on the answers to these questions. Nevertheless, the aim of the authors is to give a base enough to know what the laser is and how it acts. For that, the answer I gave to my questions is that the reader should understand the article and have enough base for, at least, reading critically the articles about laser published in urological journals.

  9. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.


    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  10. Lasers in cosmetic dentistry. (United States)

    Pang, Peter


    Lasers have become a necessary instrument in the esthetic restorative armamentarium. This article presents smile design guidelines for soft tissue lasers, as well as an overview of hard tissue procedures that may be performed using all-tissue lasers. The goal is to help dentists determine the appropriate laser for a given clinical situations.

  11. Laser Wire Stripper (United States)


    NASA-developed space shuttle technology is used in a laser wire stripper designed by Raytheon Company. Laser beams cut through insulation on a wire without damaging conductive metal, because laser radiation that melts plastic insulation is reflected by the metal. The laser process is fast, clean, precise and repeatable. It eliminates quality control problems and the expense of rejected wiring.

  12. High Power Vanadate lasers

    CSIR Research Space (South Africa)

    Strauss, HJ


    Full Text Available This presentation aims at the following: to develop new techniques to mount laser crystals; compare the laser properties of two equally doped, high power Nd:YVO4 and Nd: GdVO4 lasers; build a 1um vanadate laser with average output power exceeding...

  13. A laser radar experiment (United States)

    Stiglitz, Martin R.; Blanchard, Christine


    An experiment demonstrating the feasibility of using a laser radar for long-range target acquisition and tracking is discussed. A CO2 laser was used to collect range Doppler images, while a medium-power argon ion laser was employed for angular tracking. Laser-radar operation is outlined with emphasis on isotopic laser radars. Laser-radar imaging is covered, and a laser-radar range equation is given. Experimental laser-radar transmitter, receiver, and telescope are described. A 35-foot long surface-to-air missile and payload were tracked in the experiment, with the laser radar acquiring the targets as they reached 480 km in altitude, 750 km from the radar site. The 4-ft-diameter aperture laser-radar telescope provided the resolution and range accuracy equivalent to that of a 120-ft microwave radar antenna.

  14. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov


    The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber......-laser cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle Studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  15. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre......-laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single...

  16. The laser in urology (United States)

    Hofstetter, Alfons G.


    Laser is an acronym for a physical principle and means: Light Amplification by stimulated Emission of Radiation. This principle offers a lot of tissue/light effects caused by the parameters: power density/time and the special qualities of the laser light. Nowadays for diagnosis and therapy following lasers are used in urology: Krypton- and Dye-lasers as well as the Neodymium-YAG- (nd:YAG-), Holmium-YAG (Ho:YAG-), Diode-, Argon- and the CO2-lasers.

  17. Laser ablation principles and applications

    CERN Document Server


    Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

  18. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos


    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  19. Raman fiber lasers

    CERN Document Server


    This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

  20. Laser-surface interactions

    CERN Document Server

    Ganeev, Rashid A


    This book is about the interaction of laser radiation with various surfaces at variable parameters of radiation. As a basic principle of classification we chose the energetic or intensity level of interaction of laser radiation with the surfaces. These two characteristics of laser radiation are the most important parameters defining entire spectrum of the processes occurring on the surfaces during interaction with electromagnetic waves. This is a first book containing a whole spectrum of the laser-surface interactions distinguished by the ranges of used laser intensity. It combines the surface response starting from extremely weak laser intensities (~1 W cm-2) up to the relativistic intensities (~1020 W cm-2 and higher). The book provides the basic information about lasers and acquaints the reader with both common applications of laser-surface interactions (laser-related printers, scanners, barcode readers, discs, material processing, military, holography, medicine, etc) and unusual uses of the processes on t...

  1. Double conjugate laser amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Daunt, G.H.


    This paper describes a double conjugate laser amplifier system for producing a stable output laser beam in line with a laser oscillator input beam. It comprises: a laser oscillator which produces a low energy oscillator laser beam therefrom directly along a laser beam axis of the system; an amplification means comprised of double conjugate laser amplifiers further comprised of a first and a second singly phase conjugate amplifiers laterally opposite each other about the laser beam axis; polarizers with one of the polarizers positioned between each of the first and second singly phase conjugate amplifiers on the laser beam axis; Pockels cells with on of the Pockels cells positioned on the laser beam axis immediately prior to one of the polarizers; and a means for selectively switching the amplifier means comprised of applying a half-wave voltage at each of the Pockels cells to provide a polarization rotation of the input beam through 90{degrees} for routing of the oscillator laser beam directly through or reflected off the polarizes as an input beam to the amplification means wherein the amplification means amplifies the input beam twice in each of the first and second singly phase conjugate amplifiers and reflects the amplified laser beam off the polarizers as an amplified laser output beam in exactly the same direction as the input laser beam.

  2. Lasers in periodontics. (United States)

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie


    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  3. Laser materials processing with diode lasers


    Li, Lin; Lawrence, Jonathan; Spencer, Julian T.


    Laser materials processing is currently dominated by CO2, Nd-YAG and Excimer lasers. Continuous advances in semiconductor laser technology over the last decade have increased the average power output of the devices annualy by two fold, resulting in the commercial availability of the diode lasers today with delivery output powers in excess of 60W in CW mode and 5kW in qasi-CW mode. The advantages of compactness, high reliability, high efficiency and potential low cost, due to the mass producti...

  4. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.


    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  5. Laser surgery - skin (United States)

    Surgery using a laser ... used is directly related to the type of surgery being performed and the color of the tissue ... Laser surgery can be used to: Close small blood vessels to reduce blood loss Remove warts , moles , sunspots, and ...

  6. Laser in operative dentistry

    Directory of Open Access Journals (Sweden)

    E. Yasini


    Full Text Available Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry, etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks around the region of laser radiation. Also due to high temperature of these lasers, pulp damage is inevitable. So today, by using the Excimer laser especially the argon floride type with a wavelength of 193 nm, the problem of heat stress have been solved, but the use of lasers in dentistry, especially for cavity preparation needs more researches and evaluations.

  7. Wavelength sweepable laser source

    DEFF Research Database (Denmark)


    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  8. Laser safety in dentistry. (United States)

    Sweeney, Caroline


    Although many regulations and standards relating to laser safety are in effect, there continue to be an average of 35 laser injuries per year. Laser safety professionals believe that this number under-represents the actual number of injuries and that many more accidents per year occur that are not documented with federal agencies. A review of these accidents has determined that failing to wear available eye protection is one of the most frequent contributing factors to laser injuries. As the purchase and use of lasers in dentistry continues to grow, so must concern for laser safety. This article provides basic information to advance the safe use of lasers in dentistry and to help establish laser safety protocols for the dental office.

  9. Transmyocardial Laser Revascularization (United States)

    ... Vascular Access for Hemodialysis Ventricular Assist Devices Transmyocardial Laser Revascularization Like every other organ or tissue in ... bypass surgery, there is a procedure called transmyocardial laser revascularization, also called TMLR or TMR. TMLR cannot ...

  10. Laser particle sorter (United States)

    Martin, J.C.; Buican, T.N.


    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  11. Laser-assisted electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, D.F.


    The effect of laser irradiation on electrodeposition processes has been investigated. These studies demonstrated that the addition of laser irradiation to an electroplating process can dramatically enhance plating rates and current efficiencies, as well as improve the morphology of the resultant electrodeposit. During the course of these investigations, the mechanism for the laser enhancement of electrodeposition processes was determined. Experimental evidence was obtained to show that laser irradiation of the substrate results in increased metal ion concentrations at the surface of the electrode due to a laser-induced Soret effect. The laser-induced Soret effect has important implications for laser-assisted electrochemical processing. The increase in the surface concentration of ions allows efficient electrodeposition from dilute solutions. As such, laser- assisted electrodeposition may develop into an environmentally conscious manufacturing process by reducing waste and limiting worker exposure to toxic chemicals.

  12. Laser Processing and Chemistry

    CERN Document Server

    Bäuerle, Dieter


    This book gives an overview of the fundamentals and applications of laser-matter interactions, in particular with regard to laser material processing. Special attention is given to laser-induced physical and chemical processes at gas-solid, liquid-solid, and solid-solid interfaces. Starting with the background physics, the book proceeds to examine applications of lasers in “standard” laser machining and laser chemical processing (LCP), including the patterning, coating, and modification of material surfaces. This fourth edition has been enlarged to cover the rapid advances in the understanding of the dynamics of materials under the action of ultrashort laser pulses, and to include a number of new topics, in particular the increasing importance of lasers in various different fields of surface functionalizations and nanotechnology. In two additional chapters, recent developments in biotechnology, medicine, art conservation and restoration are summarized. Graduate students, physicists, chemists, engineers, a...

  13. Lasers in Electronic Warfare (United States)

    Manke, Gerald C.


    The use of lasers for Electronic Warfare applications will be discussed and reviewed. Specific examples of deployed EW systems which include lasers will be presented along with a discussion of their most salient features.

  14. LASIK - Laser Eye Surgery (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Glaucoma Education Center Pediatric Ophthalmology Education Center Oculofacial Plastic ... Center Laser Surgery Education Center Redmond Ethics Center ...

  15. Laser Micromachining of Ceramics


    SCITI, Diletta; Bellosi, Alida


    Laser surface processing of ceramics is an area of considerable technological importance for several structural, tribological, optical and electronic applications. The laser beam behaves as a heat source that induces a temperature rise on the surface and within the bulk of the material. Depending on laser parameters and material characteristics, lasers can be used for fabricating microholes at designated locations, for cutting, scribing, for surface modifications In this work different types ...

  16. Tunable laser optics

    CERN Document Server

    Duarte, FJ


    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  17. Lasers in periodontics


    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie


    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20 th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging imp...

  18. Tunable high pressure lasers (United States)

    Hess, R. V.


    Atmospheric transmission of high energy CO2 lasers is considerably improved by high pressure operation which, due to pressure broadening, permits tuning the laser lines off atmospheric absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers and for vertical transmission through the entire atmosphere. Applications of tunable high pressure CO2 lasers to energy transmission and to remote sensing are discussed along with initial efforts in tuning high pressure CO2 lasers.

  19. Laser cutting system (United States)

    Dougherty, Thomas J


    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  20. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.


    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA.......Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  1. Laser Stabilization with Laser Cooled Strontium

    DEFF Research Database (Denmark)

    Christensen, Bjarke Takashi Røjle

    the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter...

  2. LaserFest Celebration

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Alan Chodos; Elizabeth A. Rogan


    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  3. Lasers for nonlinear microscopy. (United States)

    Wise, Frank


    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

  4. Fiber Lasers V

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes


    High-power fiber lasers and amplifiers have gained tremendous momentum in the last five years, and many of the traditional manufactures of gas and solid-state lasers are pursuing the attractive fiber-based systems, which are now displacing the old technology in many areas. High-power fiber laser ...

  5. Laser Programs Highlights 1998

    Energy Technology Data Exchange (ETDEWEB)

    Lowdermilk, H.; Cassady, C.


    This report covers the following topics: Commentary; Laser Programs; Inertial Confinement Fusion/National Ignition Facility (ICF/NIF); Atomic Vapor Laser Isotope Separation (AVLIS); Laser Science and Technology (LS&T); Information Science and Technology Program (IS&T); Strategic Materials Applications Program (SMAP); Medical Technology Program (MTP) and Awards.

  6. ALMDS laser system (United States)

    Kushina, Mark E.; Heberle, Geoff; Hope, Michael; Hall, David; Bethel, Michael; Calmes, Lonnie K.


    The ALMDS (Airborne Laser Mine Detection System) has been developed utilizing a solid-state laser operating at 532nm for naval mine detection. The laser system is integrated into a pod that mounts externally on a helicopter. This laser, along with other receiver systems, enables detailed underwater bathymetry. CEO designs and manufactures the laser portion of this system. Arete Associates integrates the laser system into the complete LIDAR package that utilizes sophisticated streak tube detection technology. Northrop Grumman is responsible for final pod integration. The laser sub-system is comprised of two separate parts: the LTU (Laser Transmitter Unit) and the LEU (Laser Electronics Unit). The LTU and LEU are undergoing MIL-STD-810 testing for vibration, shock, temperature storage and operation extremes, as well as MIL-STD-704E electrical power testing and MIL-STD-461E EMI testing. The Nd:YAG MOPA laser operates at 350 Hz pulse repetition frequency at 45 Watts average 532nm power and is controlled at the system level from within the helicopter. Power monitor circuits allow real time laser health monitoring, which enables input parameter adjustments for consistent laser behavior.

  7. Compact Hybrid Laser Rod and Laser System (United States)

    Busch, George E. (Inventor); Amzajerdian, Farzin (Inventor); Pierrottet, Diego F. (Inventor)


    A hybrid fiber rod includes a fiber core and inner and outer cladding layers. The core is doped with an active element. The inner cladding layer surrounds the core, and has a refractive index substantially equal to that of the core. The outer cladding layer surrounds the inner cladding layer, and has a refractive index less than that of the core and inner cladding layer. The core length is about 30 to 2000 times the core diameter. A hybrid fiber rod laser system includes an oscillator laser, modulating device, the rod, and pump laser diode(s) energizing the rod from opposite ends. The rod acts as a waveguide for pump radiation but allows for free-space propagation of laser radiation. The rod may be used in a laser resonator. The core length is less than about twice the Rayleigh range. Degradation from single-mode to multi-mode beam propagation is thus avoided.

  8. Laser in ophthalmology. Laser i oftalmologien

    Energy Technology Data Exchange (ETDEWEB)

    Syrdalen, P. (Rikshospitalet, Oslo (Norway))


    The article presents a brief history of the use of laser in ophthalmology in Norway, from the introduction of the first argon-photocoalulator in 1972 to the excimer laser in 1990. The argon-photocoagulator is in daily us in all Eye Departments in Norway and the main group of patients treated are those with diabetic retionopathy. Glaucoma has been treated with argon-laser with good results for the last ten years. YAG-laser, introduced in Norway in 1985, is used to treat secondary cataracts which occur after extracapsular cataract extractions and implantation of artificial lenses. In 1990, the excimer laser was introduced for refractive surgery (myopia, astigmatism). 4 refs., 6 figs., 1 tab.

  9. Diode laser and endoscopic laser surgery. (United States)

    Sullins, Kenneth E


    Two functionally important differences exist between the diode laser and the carbon dioxide (CO2) laser (used more commonly in small animal surgery). Diode laser energy is delivered through a quartz fiber instead of being reflected through an articulated arm or waveguide. Quartz fibers are generally more flexible and resilient than waveguides and can be inserted through an endoscope for minimally invasive procedures. Laser-tissue interaction is the other significant difference. The CO2 laser is completely absorbed by water, which limits the effect to visible tissue. The diode wavelength is minimally absorbed by water and may affect tissue as deep as 10 mm below the surface in the free-beam mode. With proper respect for the tissue effect, these differences can be used to the advantage of the patient.

  10. Quantum well lasers

    CERN Document Server

    Zory, Jr, Peter S; Kelley, Paul


    This book provides the information necessary for the reader to achieve a thorough understanding of all aspects of QW lasers - from the basic mechanism of optical gain, through the current technolgoical state of the art, to the future technologies of quantum wires and quantum dots. In view of the growing importance of QW lasers, this book should be read by all those with an active interest in laser science and technology, from the advanced student to the experienced laser scientist.* The first comprehensive book-length treatment of quantum well lasers* Provides a detailed treatment

  11. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff; Hitz, C Breck; John Wiley & Sons


    Electrical Engineering Introduction to Laser Technology , Third Edition. Would you like to know how a laser works, and how it can be modified for your own specific tasks? This intuitive third edition-previously published as Understanding Laser Technology , First and Second Editions-introduces engineers, scientists, technicians, and novices alike to the world of modern lasers, without delving into the mathematical details of quantum electronics. It is the only introductory text on the market today that explains the underlying physics and engineering applicable to all lasers. A unique combinatio.

  12. Tunable laser applications

    CERN Document Server

    Duarte, FJ


    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  13. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud


    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

  14. Lasers in otorhinolaryngology (United States)

    Pais Clemente, Manuel P.


    Lasers are now commonly accepted and widely used surgical instruments in otorhinolaryngology. There have been a great number of technological advances with lasers that have contributed to the expansion of this new surgical modality with an increased number of medical applications. Surgical strategies have also changed and are more favorable toward conservative surgery in which less tissues is removed than with more radical resections. This combination of improving technology and medical attitudes has changed the field of otorhinolaryngology, and resulted in an expanding use of laser surgery. Since 1973 we have been using the carbon dioxide laser in the treatment of diseases of the upper aero digestive systems, learning this new surgical technique from the pioneer work of Strong, Jako, and Vaughan. It is our conviction that a laser surgeon must have a thorough knowledge of laser biophysics, instrumentation, safety protocols, and surgical indications, and have the technical skills to perform laser surgery. Laser technology continues to improve at an increased speed, and it is imperative to update knowledge of current and potential applications of lasers in our specialty. It is the purpose of this article to present our clinical experience of 18 years with the use of lasers in surgery of ORL, emphasizing the carbon dioxide laser.

  15. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid


    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  16. [Navigated retinal laser therapy]. (United States)

    Kernt, M; Ulbig, M; Kampik, A; Neubauer, A S


    Navigated laser therapy introduces for the first time computerized assistance systems for retinal laser therapy. The Navilas system offers high precision and safety and provides additional benefits regarding standardization of planning, execution, documentation and quality assurance. The current focus of clinical application for navigated laser therapy besides laser treatment after retinal vein occlusion and panretinal laser photocoagulation in proliferative diabetic retinopathy (PDR) is diabetic macular edema. Recent data indicate that combined initial anti-vascular endothelial growth factor (anti-VEGF) and navigated macular laser therapy allows achievement and maintenance of treatment success with a minimum number of interventions. Despite very promising results the current assessment of navigated laser therapy is still limited by the evidence available worldwide.

  17. Laser beam shaping techniques

    Energy Technology Data Exchange (ETDEWEB)



    Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

  18. Laser safety in dentistry (United States)

    Wigdor, Harvey A.


    One of the major causes of anxiety in the dental clinic is the dental handpiece. Because dentists wish to provide a method which can replace the drill there has often been a premature use of the laser in dentistry. Various lasers have been introduced into the clinic before research has shown the laser used is of clinical benefit. Any new treatment method must not compromise the health of the patient being treated. Thus a method of evaluating the clinical abilities of dentists and their understanding the limitations of the laser used must be developed. Dentist must be trained in the basic interaction of the laser on oral tissues. The training has to concentrate on the variation of the laser wavelength absorption in the different tissues of the oral cavity. Because of the differences in the optical properties of these tissues great care must be exercised by practitioners using lasers on patients.

  19. Lasers in periodontology. (United States)

    Mavrogiannis, M; Thomason, J M; Seymour, R A


    Since the development of the ruby laser by Maiman in 1960, lasers have been widely employed in medicine for a number of years. The purpose of this paper is to summarize potential applications for lasers in dentistry, with special regard to periodontology. This article briefly describes clinical applications of lasers and laser safety. Particularly, the use of a diode laser seems to be promising, especially in already compromised transplant patients, who need to be treated with a technique where the operative and post-operative blood loss, post-operative discomfort and the recurrence of drug-induced gingival overgrowth need to be kept to a minimum or eliminated. Therefore, the use of lasers in periodontology may lead to an alteration in present clinical practice and help to establish the best management strategy because, by maintaining periodontal health, the life quality of patients can be improved.

  20. Lasers in oral surgery (United States)

    Keller, Ulrich; Hibst, Raimund


    The indications of lasers in oral surgery are defined by the laser-tissue interaction types. These are mainly thermal effects depending especially on the absorption of laser light in varying biological tissues. In histological sections different laser effects are demonstrated on oral mucosa, bone and cartilage, which have a great influence on wound healing and subsequently on clinical indications of the different wavelengths. On the one hand the good coagulation effect of the Nd:YAG laser is wanted for hemostasis in soft tissue surgery. On the other hand, for the treatment of precancerous dysplasias or neoplasias an effective cutting with a coagulation effect like using the CO2 laser is necessary. However, the excision of benign mucosal lesions as well as performing osteotomies or shaping of cartilage should be undertaken with the Er:YAG laser without greater coagulation and consequently without any delay of wound healing.

  1. Lasers in orthodontics (United States)

    Nalcaci, Ruhi; Cokakoglu, Serpil


    Many types of dental lasers are currently available that can be efficiently used for soft and hard tissue applications in the field of orthodontics. For achieving the desired effects in the target tissue, knowledge of laser characteristics such as power, wavelength and timing, is necessary. Laser therapy is advantageous because it often avoids bleeding, can be pain free, is non-invasive and is relatively quick. The high cost is its primary disadvantage. It is very important to take the necessary precautions to prevent possible tissue damage when using laser dental systems. Here, we reviewed the main types and characteristics of laser systems used in dental practice and discuss the applications of lasers in orthodontics, harmful effects and laser system safety. PMID:24966719

  2. Laser Applications in Orthodontics (United States)

    Heidari, Somayeh; Torkan, Sepideh


    A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field. PMID:25606324

  3. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten


    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  4. Mode selection laser

    DEFF Research Database (Denmark)


    The invention relates to a semiconductor mode selection laser, particularly to a VCSEL laser (200) having mode selection properties. The mode selection capability of the laser is achieved by configuring one of the reflectors (15,51) in the resonance cavity so that a reflectivity of the reflector...... (15) varies spatially in one dimension or two dimensions. Accordingly, the reflector (15) with spatially varying reflectivity is part both of the resonance cavity and the mode selection functionality of the laser. A plurality of the lasers configured with different mode selectors, i.e. different...... spatial reflector variations, may be combined to generate a laser beam containing a plurality of orthogonal modes. The laser beam may be injected into a few- mode optical fiber, e.g. for the purpose of optical communication. The VCSEL may have intra-cavity contacts (31,37) and a Tunnel junction (33...

  5. Laser system using ultra-short laser pulses (United States)

    Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI


    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  6. Frequency comb swept lasers. (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G


    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  7. Photobiomodulation in laser surgery (United States)

    Liu, Timon Cheng-Yi; Rong, Dong-Liang; Huang, Jin; Deng, Xiao-Yuan; Liu, Song-Hao


    Laser surgery provides good exposure with clear operating fields and satisfactory preliminary functional results. In contrast to conventional excision, it was found that matrix metalloproteinases and the tissue inhibitors of metalloproteinases -1 mRNA expression is higher, myofibroblasts appeared and disappeared slower in laser excision wounds. It has been suggested that the better anatomical and functional results achieved following laser cordectomy may be explained by the fact that such procedures result in better, more rapid healing processes to recover vocal cord for early glottic tumors and better. In this paper, the role of photobiomodulation in laser surgery will be discussed by the cultured monolayer normal human skin fibroblast model of the photobiomodulation of marginal irradiation of high intensity laser beam, the photobiomodulation related to the irradiated tissue, the biological information model of photobiomodulation and the animal models of laser surgery. Although high intensity laser beam is so intense that it destroys the irradiated cells or tissue, its marginal irradiation intensity is so low that there is photobiomodulation on non-damage cells to modulate the regeneration of partly damaged tissue so that the surgery of laser of different parameters results in different post-surgical recovery. It was concluded that photobiomodulation might play an important role in the long-term effects of laser surgery, which might be used to design laser surgery.

  8. Laser treatment in gynecology (United States)

    de Riese, Cornelia


    This presentation is designed as a brief overview of laser use in gynecology, for non-medical researchers involved in development of new laser techniques. The literature of the past decade is reviewed. Differences in penetration, absorption, and suitable delivery media for the beams dictate clinical application. The use of CO2 laser in the treatment of uterine cervical intraepithelial lesions is well established and indications as well as techniques have not changed over 30 years. The Cochrane Systematic Review from 2000 suggests no obviously superior technique. CO2 laser ablation of the vagina is also established as a safe treatment modality for VAIN. CO2 laser permits treatment of lesions with excellent cosmetic and functional results. The treatment of heavy menstrual bleeding by destruction of the endometrial lining using various techniques has been the subject of a 2002 Cochran Database Review. Among the compared treatment modalities are newer and modified laser techniques. Conclusion by reviewers is that outcomes and complication profiles of newer techniques compare favorably with the gold standard of endometrial resection. The ELITT diode laser system is one of the new successful additions. CO2 laser is also the dominant laser type used with laparoscopy for ablation of endometriotic implants. Myoma coagulation or myolysis with Nd:Yag laser through the laparoscope or hysteroscope is a conservative treatment option. Even MRI guided percutaneous approaches have been described. No long-term data are available.

  9. Laser scanning laser diode photoacoustic microscopy system. (United States)

    Erfanzadeh, Mohsen; Kumavor, Patrick D; Zhu, Quing


    The development of low-cost and fast photoacoustic microscopy systems enhances the clinical applicability of photoacoustic imaging systems. To this end, we present a laser scanning laser diode-based photoacoustic microscopy system. In this system, a 905 nm, 325 W maximum output peak power pulsed laser diode with 50 ns pulsewidth is utilized as the light source. A combination of aspheric and cylindrical lenses is used for collimation of the laser diode beam. Two galvanometer scanning mirrors steer the beam across a focusing aspheric lens. The lateral resolution of the system was measured to be ∼21 μm using edge spread function estimation. No averaging was performed during data acquisition. The imaging speed is ∼370 A-lines per second. Photoacoustic microscopy images of human hairs, ex vivo mouse ear, and ex vivo porcine ovary are presented to demonstrate the feasibility and potentials of the proposed system.

  10. Lasers in medicine

    Energy Technology Data Exchange (ETDEWEB)

    Peng Qian [Department of Pathology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo (Norway); Juzeniene, Asta; Moan, Johan [Department of Radiation Biology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo (Norway); Chen Jiyao [State Key Laboratory for Advanced Photonic Materials and Devices, Fudan University, 200433 Shanghai (China); Svaasand, Lars O [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, O.S. Bragstads Plass 2A, 7491 Trondheim (Norway); Warloe, Trond; Giercksky, Karl-Erik [Department of Surgical Oncology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo (Norway)], E-mail:


    It is hard to imagine that a narrow, one-way, coherent, moving, amplified beam of light fired by excited atoms is powerful enough to slice through steel. In 1917, Albert Einstein speculated that under certain conditions atoms could absorb light and be stimulated to shed their borrowed energy. Charles Townes coined the term laser (light amplification by stimulated emission of radiation) in 1951. Theodore Maiman investigated the glare of a flash lamp in a rod of synthetic ruby, creating the first human-made laser in 1960. The laser involves exciting atoms and passing them through a medium such as crystal, gas or liquid. As the cascade of photon energy sweeps through the medium, bouncing off mirrors, it is reflected back and forth, and gains energy to produce a high wattage beam of light. Although lasers are today used by a large variety of professions, one of the most meaningful applications of laser technology has been through its use in medicine. Being faster and less invasive with a high precision, lasers have penetrated into most medical disciplines during the last half century including dermatology, ophthalmology, dentistry, otolaryngology, gastroenterology, urology, gynaecology, cardiology, neurosurgery and orthopaedics. In many ways the laser has revolutionized the diagnosis and treatment of a disease. As a surgical tool the laser is capable of three basic functions. When focused on a point it can cauterize deeply as it cuts, reducing the surgical trauma caused by a knife. It can vaporize the surface of a tissue. Or, through optical fibres, it can permit a doctor to see inside the body. Lasers have also become an indispensable tool in biological applications from high-resolution microscopy to subcellular nanosurgery. Indeed, medical lasers are a prime example of how the movement of an idea can truly change the medical world. This review will survey various applications of lasers in medicine including four major categories: types of lasers, laser

  11. Dermatological laser treatment. Dermatologisk laserbehandling

    Energy Technology Data Exchange (ETDEWEB)

    Moerk, N.J.; Austad, J. (Rikshospitalet, Oslo (Norway)); Helland, S. (Haukeland Sykehus, Bergen (Norway)); Thune, P. (Ullevaal Sykehus, Oslo (Norway)); Volden, G. (University and Regional Hospital, Trondheim (Norway)); Falk, E. (University and Regional Hospital, Tromsoe (Norway))


    The article reviews the different lasers used in dermatology. Special emphasis is placed on the treatment of naevus flammeus (''portwine stain'') where lasers are the treatment of choice. Argon laser and pulsed dye laser are the main lasers used in vascular skin diseases, and the article focuses on these two types. Copper-vapour laser, neodymium-YAG laser and CO{sub 2} laser are also presented. Information is provided about the availability of laser technology in the different health regions in Norway. 5 refs., 2 figs.

  12. High power lasers in manufacturing


    Chatwin, Chris R


    Lecture covers a brief history of lasers and the important beam parameters for manufacturing applications. It introduces the main laser types that are appropriate for manufacturing: carbon dioxide lasers, Nd YAG, Diode and fibre lasers, excimer lasers. It then looks at applications to different products and also micro-engineering

  13. Nuclear-pumped lasers

    CERN Document Server

    Prelas, Mark


    This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

  14. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude


    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  15. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui


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

  16. Lasers in periodontics

    Directory of Open Access Journals (Sweden)

    Sugumari Elavarasu


    Full Text Available Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20 th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  17. Nanofabrication with Pulsed Lasers

    Directory of Open Access Journals (Sweden)

    Kabashin AV


    Full Text Available Abstract An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3, is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.

  18. Principles of Lasers

    CERN Document Server

    Svelto, Orazio


    This new Fifth Edition of Principles of Lasers incorporates corrections to the previous edition. The text’s essential mission remains the same: to provide a wide-ranging yet unified description of laser behavior, physics, technology, and current applications. Dr. Svelto emphasizes the physical rather than the mathematical aspects of lasers, and presents the subject in the simplest terms compatible with a correct physical understanding. Praise for earlier editions: "Professor Svelto is himself a longtime laser pioneer and his text shows the breadth of his broad acquaintance with all aspects of the field … Anyone mastering the contents of this book will be well prepared to understand advanced treatises and research papers in laser science and technology." (Arthur L. Schawlow, 1981 Nobel Laureate in Physics) "Already well established as a self-contained introduction to the physics and technology of lasers … Professor Svelto’s book, in this lucid translation by David Hanna, can be strongly recommended for...

  19. Lasers in periodontics (United States)

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie


    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics. PMID:23066266

  20. Laser rocket system analysis (United States)

    Jones, W. S.; Forsyth, J. B.; Skratt, J. P.


    The laser rocket systems investigated in this study were for orbital transportation using space-based, ground-based and airborne laser transmitters. The propulsion unit of these systems utilizes a continuous wave (CW) laser beam focused into a thrust chamber which initiates a plasma in the hydrogen propellant, thus heating the propellant and providing thrust through a suitably designed nozzle and expansion skirt. The specific impulse is limited only by the ability to adequately cool the thruster and the amount of laser energy entering the engine. The results of the study showed that, with advanced technology, laser rocket systems with either a space- or ground-based laser transmitter could reduce the national budget allocated to space transportation by 10 to 345 billion dollars over a 10-year life cycle when compared to advanced chemical propulsion systems (LO2-LH2) of equal capability. The variation in savings depends upon the projected mission model.

  1. Laser/tissue interaction. (United States)

    Dederich, D N


    When laser light impinges on tissue, it can reflect, scatter, be absorbed, or transmit to the surrounding tissue. Absorption controls to a great degree the extent to which reflection, scattering and transmission occur, and wavelength is the primary determinant of absorption. The CO2 laser is consistently absorbed by most materials and tissues and the Nd-YAG laser wavelength is preferentially absorbed in pigmented tissues. The factors which determine the initial tissue effect include the laser wavelength, laser power, laser waveform, tissue optical properties, and tissue thermal properties. There are almost an infinite number of combinations of these factors possible, many of which would result in unacceptable damage to the tissues. This underscores the need to thoroughly test any particular combination of these factors on the conceptual, in-vitro, and in-vivo level before a treatment is offered.

  2. Strong field laser physics

    CERN Document Server


    Since the invention of the laser in the 1960s, people have strived to reach higher intensities and shorter pulse durations. High intensities and ultrashort pulse durations are intimately related. Recent developments have shown that high intensity lasers also open the way to realize pulses with the shortest durations to date, giving birth to the field of attosecond science (1 asec = 10-18s). This book is about high-intensity lasers and their applications. The goal is to give an up to date introduction to the technology behind these laser systems and to the broad range of intense laser applications. These applications include AMO (atomic molecular and optical) physics, x-ray science, attosecond science, plasma physics and particle acceleration, condensed matter science and laser micromachining, and finally even high-energy physics.

  3. Atomic iodine laser

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, G.A.; Gusinow, M.A.; Hays, A.K.; Padrick, T.D.; Palmer, R.E.; Rice, J.K.; Truby, F.K.; Riley, M.E.


    The atomic iodine photodissociation laser has been under intensive study for a number of years. The physics associated with this system is now well understood and it is possible to produce a 0.1 nsec (or longer) near-diffraction-limited laser pulse which can be amplified with negligible temporal distortion and little spatial deformation. The output of either a saturated or unsaturated amplifier consists of a high-fidelity near-diffraction-limited, energetic laser pulse. The report is divided into three chapters. Chapter 1 is a survey of the important areas affecting efficient laser operation and summarizes the findings of Chap. 2. Chapter 2 presents detailed discussions and evaluations pertinent to pumps, chemical regeneration, and other elements in the overall laser system. Chapter 3 briefly discusses those areas that require further work and the nature of the work required to complete the full-scale evaluation of the applicability of the iodine photodissociation laser to the inertial confinement program.

  4. Laser In Veterinary Medicine (United States)

    Newman, Carlton; Jaggar, David H.


    Lasers have been used for some time now on animals for experimental purposes prior to their use in human medical and surgical fields. However the use of lasers in veterinary medicine and surgery per se is a recent development. We describe the application of high and low intensity laser technology in a general overview of the current uses, some limitations to its use and future needs for future inquiry and development.

  5. Lasers in orthodontics


    Nalcaci, Ruhi; Cokakoglu, Serpil


    Many types of dental lasers are currently available that can be efficiently used for soft and hard tissue applications in the field of orthodontics. For achieving the desired effects in the target tissue, knowledge of laser characteristics such as power, wavelength and timing, is necessary. Laser therapy is advantageous because it often avoids bleeding, can be pain free, is non-invasive and is relatively quick. The high cost is its primary disadvantage. It is very important to take the necess...

  6. Polarization feedback laser stabilization (United States)

    Esherick, P.; Owyoung, A.


    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  7. Laser precision microfabrication

    CERN Document Server

    Sugioka, Koji; Pique, Alberto


    Miniaturization and high precision are rapidly becoming a requirement for many industrial processes and products. As a result, there is greater interest in the use of laser microfabrication technology to achieve these goals. This book composed of 16 chapters covers all the topics of laser precision processing from fundamental aspects to industrial applications to both inorganic and biological materials. It reviews the sate of the art of research and technological development in the area of laser processing.

  8. Infrared diode lasers (United States)

    Lo, Wayne


    This paper reviews the development of infrared diode lasers for automobile exhaust gas analysis and high resolution spectroscopy at the General Motors Research Laboratories. Advances in lead-salt crystal growth technology and laser fabrication techniques to achieve high temperature operation and wide frequency tuning range will be discussed. Recent developments in improving the long-term reliability of the laser will also be reviewed.

  9. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff


    The only introductory text on the market today that explains the underlying physics and engineering applicable to all lasersAlthough lasers are becoming increasingly important in our high-tech environment, many of the technicians and engineers who install, operate, and maintain them have had little, if any, formal training in the field of electro-optics. This can result in less efficient usage of these important tools. Introduction to Laser Technology, Fourth Edition provides readers with a good understanding of what a laser is and what it can and cannot do. The book explains what types of las.

  10. Gigashot Optical Laser Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Deri, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  11. Lasers for Onychomycosis. (United States)

    Gupta, Aditya K; Foley, Kelly A; Versteeg, Sarah G

    Many studies that have been recently published investigate the efficacy of laser treatment for onychomycosis. These studies support the current US Food and Drug Administration (FDA) approval of lasers for the 'temporary increase in clear nail'. Clear nail growth is an important treatment goal for patients; however, many do not realise that laser treatment is not a cure for onychomycosis. The current article briefly reviews why lasers may be theoretically effective in treating onychomycosis and critically reviews published laser studies for onychomycosis in light of the standards employed in drug trials. Treatment regimens, efficacy endpoints, and the unit of analysis (nails vs patients) vary widely among published laser studies. Complete cure, mycological cure, and clinical improvement rates in laser studies are not reported or use such disparate criteria that comparison among studies is not possible. The US FDA has recently published guidelines for the use of medical devices in clinical trial design for onychomycosis. Future laser studies should adopt the FDA's guidelines to allow for more consistency within the field and focus on the efficacy of lasers as monotherapy for onychomycosis.

  12. X-ray lasers

    CERN Document Server

    Elton, Raymond C


    The first in its field, this book is both an introduction to x-ray lasers and a how-to guide for specialists. It provides new entrants and others interested in the field with a comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. In one succinct volume, X-Ray Lasers collects the knowledge and experience gained in two decades of x-ray laser development and conveys the exciting challenges and possibilities still to come._Add on for longer version of blurb_M>The reader is first introduced

  13. High power lasers

    CERN Document Server

    Niku-Lari, A


    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  14. Physics of semiconductor lasers

    CERN Document Server

    Mroziewicz, B; Nakwaski, W


    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  15. Principles of laser dynamics

    CERN Document Server

    Khanin, YI


    This monograph summarizes major achievements in laser dynamics over the past three decades. The book begins with two introductory Chapters. Chapter 1 offers general considerations on quantum oscillators, formulates the requirements for the laser key elements and shows how these requirements are met in different laser systems. The second Chapter proposes the mathematical models used in semiclassical laser theory, discusses the approximations and simplifications in particular cases, and specifies the range of applicability of these models. In Chapters 3-5 attention is given primarily to the stea

  16. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter


    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  17. Transscleral laser for ophthalmology (United States)

    Pekarik, Alexander S.; Linnik, Leonid A.; Kadan, Victor N.


    Transscleral laser (YAG:Nd, (lambda) equals 1.06 micrometers ) for ophthalmology has been developed and assembled for pulse laser transscleral treatment of eyes structures by means of adaptive optical fibers tip. `Adaptivity' means that we have used some exactly defined levels of optical fiber tip contact pressure to eyes surface to replace intertissues liquid. Such kind of fiber tip permit us apply more laser irradiation power due to decreasing of laser beam absorption in the liquid of eyes tissue. The different laser power levels, pulse duration, exposure time have been considered in correspondence with many types of adaptive fiber optical tips to optimize both transscleral coagulation and cutting process. To exactly determine the dependencies of laser irradiation spatial distributions behind sclera via contact tips pressure levels we have used as a adequate enough model He-Ne laser and eyes tissue samples. Laser system consist of power supply, control unit, laser head with cooling system, adapter for different kind of optical fibers tips. All of the above has been mounted as one case.

  18. Lasers for Frontier Spectroscopy (United States)

    Baldacchini, Giuseppe

    The first laser has been invented in 1960 by using the red light from a ruby crystal, and since then the laser field exploded almost exponentially, and thousands of different materials, in the state of solids, liquids, vapors, gases, plasmas, and elementary particles have lased up to now from less than I Å to more than 1 mm. Many of them have been used with outstanding results both in basic science, and in industrial and commercial applications, by changing for ever the same lifestyle of humankind. As far as spectroscopy is concerned, the laser light has started an unprecedented revolution because of its unique properties as monochromaticity, coherence, power, brightness and short-pulse regime, unrivaled by any other natural and artificial light source. Spectroscopy applications increased qualitatively and quantitatively with the laser sources themselves, and they are still proceeding in parallel with the moving of the laser field towards new territories. Apart the opening up of new regions of the electromagnetic spectrum, like the terahertz gap, and the outstanding increase of the output power which is giving rise to completely new spectroscopic effects, the improvement of laser sources and auxiliary equipment is producing a growth of traditional laser spectroscopy with superior resolution and sensitivity. Moreover, spectroscopic techniques and laser light contributed to the development of new chemical and physical processes which have been used to fabricate photonic materials with new spectroscopic properties enriching the laser field itself, in a virtuous cycle spectroscopy→aser→material and back to spectroscopy with no end in sight.

  19. Lasers in materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.I.; Rockower, E.B.


    A status report on the uranium Laser Isotope Separation (LIS) Program at the Lawrence Livermore National Laboratory is presented. Prior to this status report, process economic analysis is presented so as to understand how the unique properties of laser photons can be best utilized in the production of materials and components despite the high cost of laser energy. The characteristics of potential applications that are necessary for success are identified, and those factors that have up to now frustrated attempts to find commercially viable laser induced chemical and physical process for the production of new or existing materials are pointed out.

  20. Laser adaptive holographic hydrophone

    Energy Technology Data Exchange (ETDEWEB)

    Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A [Institute of Automation and Control Processes, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok (Russian Federation)


    A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)

  1. Laser Program annual report 1987

    Energy Technology Data Exchange (ETDEWEB)

    O' Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)


    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  2. [Characteristics of laser light]. (United States)

    Takac, S; Stojanović, S


    Laser is one of the greatest technical discoveries of the 20th century. It is important in basic sciences, but particularly in diagnosis and therapy of various pathologic conditions of human organism. It is electromagnetic radiation, not X-irradiation and, as such, it is not expected to produce new generation of iatrogenic malignancies. Laser falls between infrared and ultraviolet on the spectrum mainly in the visible light spectrum. Properties of laser light are: monochromacity (the same color), coherence (all of the light waves are in phase both spatially and temporally), collimation (all rays are parallel to each other and do not diverge significantly even over long distances). Lasers were first conceived by Einstein in 1917 when he wrote his "Zur Quantum Theorie der Strahlung" (the quantum theory of radiation) which enumerated concepts of stimulated and spontaneous emission and absorption. Drs. Arthur Schawlow and Charles Townes, in 1956, extended lasers into the optical frequency range and Maiman, in 1960, operated the first laser using ruby as the active medium (ruby laser). Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. To understand the acronym, it is necessary to understand the basic physics of the atom. However, if the atom that is in the excited state is struck by another photon of energy before it returns to the ground state, two photons of equal frequency and energy, travelling in the same direction and in perfect spatial and temporal harmony, are produced. This phenomenon is termed stimulated emission of radiation. An external power source hyperexcites the atoms in the laser medium so that the number of atoms possessing upper energy levels exceeds the number of atoms in a power energy level, a condition termed a population inversion. This "pumping system" which imparts additional energy to the atoms may be optical, mechanical, or chemical. These atoms in a hyperexcited state spontaneously emit photons of light. The

  3. Laser Stabilization with Laser Cooled Strontium

    DEFF Research Database (Denmark)

    Christensen, Bjarke Takashi Røjle

    The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting the nonli......The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting...... the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter......-combination line at 689 nm in a strongly saturated regime. The dynamics of the atomic induced phase shift and absorption of the probe light were experimentally studied in details with the purpose of applications to laser stabilization. The atomic sample temperature was in the mK range which brought this system out...

  4. New laser amplifier improves laser Doppler interferometry (United States)


    The design of a laser light amplifier developed to improve the ability of a laser Doppler interferometry system to measure the high velocities of explosion-driven objects or targets is described. The amplifier increases the laser light intensity and S/N ratio. A green coumarin dye is utilized as if the lasing medium for an argon-ion laser and a blue dye as the frequency shifter to improve coupling between the light-pump power source and lasing medium. The arrangement of amplifier components and the frequency characteristics of the flash lamps and dyes are examined. The design requirements for eliminating chirping and achieving acoustic isolation are discussed. The control of the thermal gradients which produce lens effect is analyzed. The selection of a proper dye concentration for uniform excitation across the active volume of the amplifier is studied; an excitation absorption length of three diameters of active cross section is utilized. In order to increase the amount of pumping light reaching the laser dye and to reduce the number of unwanted wavelengths a optical frequency shifter is employed. The amplifier produces enough light to observe two or more spots on the target, record data for up to 12 microsec, and have an accuracy of 0.5 pct.

  5. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil


    ...) technology selective laser sintering (SLS). BME has successfully implemented a pilot facility to fabricate calcium phosphate implants using anatomical data coupled with the selective laser sintering process...

  6. Laser safety tools and training

    CERN Document Server

    Barat, Ken


    Lasers perform many unique functions in a plethora of applications, but there are many inherent risks with this continually burgeoning technology. Laser Safety: Tools and Training presents simple, effective ways for users in a variety of facilities to evaluate the hazards of any laser procedure and ensure they are following documented laser safety standards.Designed for use as either a stand-alone volume or a supplement to Laser Safety Management, this text includes fundamental laser and laser safety information and critical laser use information rarely found in a single source. The first lase

  7. Laser Wakefield Accelerators


    Najmudin, Z.


    The one-dimensional wakefield generation equations are solved for increasing levels of non-linearity, to demonstrate how they contribute to the overall behaviour of a non-linear wakefield in a plasma. The effect of laser guiding is also studied as a way to increase the interaction length of a laser wakefield accelerator.

  8. Fine welding with lasers. (United States)

    MacLellan, D


    The need for micro joining metallic alloys for surgical instruments, implants and advanced medical devices is driving a rapid increase in the implementation of laser welding technology in research, development and volume production. This article discusses the advantages of this welding method and the types of lasers used in the process.

  9. Learning about Lasers (United States)

    Roberts, Larry


    The word laser is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. Lasers, invented in 1958, are used to cut and fuse materials, accurately survey long distances, communicate across fiber-optic phone lines, produce 3D pictures, make special effects, help navigation, and read bar codes for cash registers. A laser…

  10. (308 nm) excimer laser

    Indian Academy of Sciences (India)

    The UV lasers with high quantum energy photons directly break the atomic and molecular bonds within material. The photons in this spectral range are also capable of inducing photo- chemical reactions. Most solid materials have high absorption in the UV. The short pulses result in reducing interaction time between laser ...

  11. Laser applications in surgery. (United States)

    Azadgoli, Beina; Baker, Regina Y


    In modern medicine, lasers are increasingly utilized for treatment of a variety of pathologies as interest in less invasive treatment modalities intensifies. The physics behind lasers allows the same basic principles to be applied to a multitude of tissue types using slight modifications of the system. Multiple laser systems have been studied within each field of medicine. The term "laser" was combined with "surgery," "ablation," "lithotripsy," "cancer treatment," "tumor ablation," "dermatology," "skin rejuvenation," "lipolysis," "cardiology," "atrial fibrillation (AF)," and "epilepsy" during separate searches in the PubMed database. Original articles that studied the application of laser energy for these conditions were reviewed and included. A review of laser therapy is presented. Laser energy can be safely and effectively used for lithotripsy, for the treatment of various types of cancer, for a multitude of cosmetic and reconstructive procedures, and for the ablation of abnormal conductive pathways. For each of these conditions, management with lasers is comparable to, and potentially superior to, management with more traditional methods.

  12. Coherent Polariton Laser (United States)

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


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

  13. Coherent Polariton Laser

    Directory of Open Access Journals (Sweden)

    Seonghoon Kim


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

  14. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten


    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  15. Lasers in dental traumatology

    National Research Council Canada - National Science Library

    Olivi, G; Caprioglio, C; Genovese, M D


    ... connected to dental trauma, particularly in children. Furthermore, laser-assisted therapies drastically reduce the need for analgesics and anti- inflammatory medications compared with conventional procedures. Using laser equipment to obtain anaesthesia is another challenge, while the use of low power setting for desensitising tissue and to obtain anaesthesia is also an open field.

  16. Levitated droplet dye laser

    DEFF Research Database (Denmark)

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren


    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  17. Laser processing of materials

    Indian Academy of Sciences (India)

    Light amplification by stimulated emission of radiation (laser) is a coherent and monochromatic beam of electromagnetic radiation that can propagate in a straight line with negligible divergence and occur in a wide range of wavelength, energy/power and beam-modes/configurations. As a result, lasers find wide applications ...

  18. Lasers in Orthodontics

    Directory of Open Access Journals (Sweden)

    Rajesh Jayantilal Kamdar


    Summary and conclusion: Incorporation of lasers in an orthodontic practice requires thorough learning process on the part of the orthodontist. Attending various workshops and certification programs will help in mastering the science and art of laser dentistry. Needless to say, proper case selection will pave way for the successful long-term result.

  19. CO2 laser resurfacing. (United States)

    Fitzpatrick, R E


    The CO2 Laser offers a variety of unique features in resurfacing facial photodamage and acne scarring. These include hemostasis, efficient removal of the epidermis in a single pass, thermally induced tissue tightening, and safe, predictable tissue interaction. Knowledge of these mechanisms will result in the capability of using the CO2 laser effectively and safely whether the goal is superficial or deep treatment.

  20. Laser Interference Lithography

    NARCIS (Netherlands)

    van Wolferen, Hendricus A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  1. Laser biostimulation in pediatrics (United States)

    Utz, Irina A.; Lagutina, L. E.; Tuchin, Valery V.


    In the present paper the method and apparatus for percutaneous laser irradiation of blood (PLIB) in vessels (veins) are described. Results of clinical investigations of biostimulating effects under PLIB by red laser light (633 nm) in Cubiti and Saphena Magna veins are presented.

  2. Laser energy conversion (United States)

    Jalufka, N. W.


    The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

  3. Exciton laser rate equations

    Directory of Open Access Journals (Sweden)

    Garkavenko A. S.


    Full Text Available The rate equations of the exciton laser in the system of interacting excitons have been obtained and the inverted population conditions and generation have been derived. The possibility of creating radically new gamma-ray laser has been shown.

  4. Solid state laser (United States)

    Rines, Glen A. (Inventor); Moulton, Peter F. (Inventor); Harrison, James (Inventor)


    A wavelength-tunable, injection-seeded, dispersion-compensated, dispersively-pumped solid state laser includes a lasing medium; a highly reflective mirror; an output coupler; at least one isosceles Brewster prism oriented to the minimum deviation angle between the medium and the mirror for directing light of different wavelengths along different paths; means for varying the angle of the highly reflective mirror relative to the light from at least one Brewster angle for selecting a predetermined laser operating wavelength; a dispersion compensation apparatus associated with the lasing medium; a laser injection seeding port disposed between the dispersion compensation apparatus and one of the mirror and coupler and including a reflective surface at an acute non-Brewster angle to the laser beam for introducing a seed input; a dispersion compensation apparatus associated with the laser medium including opposite chirality optical elements; the lasing medium including a pump surface disposed at an acute angle to the laser beam to define a discrete path for the pumping laser beam separate from the pumped laser beam.

  5. Laser hair removal pearls. (United States)

    Tierney, Emily P; Goldberg, David J


    A number of lasers and light devices are now available for the treatment of unwanted hair. The goal of laser hair removal is to damage stem cells in the bulge of the follicle through the targeting of melanin, the endogenous chromophore for laser and light devices utilized to remove hair. The competing chromophores in the skin and hair, oxyhemoglobin and water, have a decreased absorption between 690 nm and 1000 nm, thus making this an ideal range for laser and light sources. Pearls of laser hair removal are presented in this review, focusing on four areas of recent development: 1 treatment of blond, white and gray hair; 2 paradoxical hypertrichosis; 3 laser hair removal in children; and 4 comparison of lasers and IPL. Laser and light-based technologies to remove hair represents one of the most exciting areas where discoveries by dermatologists have led to novel treatment approaches. It is likely that in the next decade, continued advancements in this field will bring us closer to the development of a more permanent and painless form of hair removal.

  6. Athermal laser launch telescopes

    NARCIS (Netherlands)

    Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.


    ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several

  7. Ceramic laser materials (United States)

    Ikesue, Akio; Aung, Yan Lin


    The word 'ceramics' is derived from the Greek keramos, meaning pottery and porcelain. The opaque and translucent cement and clay often used in tableware are not appropriate for optical applications because of the high content of optical scattering sources, that is, defects. Recently, scientists have shown that by eliminating the defects, a new, refined ceramic material - polycrystalline ceramic - can be produced. This advanced ceramic material offers practical laser generation and is anticipated to be a highly attractive alternative to conventional glass and single-crystal laser technologies in the future. Here we review the history of the development of ceramic lasers, the principle of laser generation based on this material, some typical results achieved with ceramic lasers so far, and discuss the potential future outlook for the field.

  8. Regenerative similariton laser

    Directory of Open Access Journals (Sweden)

    Thibault North


    Full Text Available Self-pulsating lasers based on cascaded reshaping and reamplification (2R are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  9. Femtosecond Laser Filamentation

    CERN Document Server

    Chin, See Leang


    Femtosecond Laser Filamentation gives a comprehensive review of the physics of propagation of intense femtosecond laser pulses in optical media (principally air) and the applications and challenges of this new technique. This book presents the modern understanding of the physics of femtosecond laser pulse propagation, including unusual new effects such as the self-transformation of the pulse into a white light laser pulse, intensity clamping, the physics of multiple filamentation and competition, and how filaments’ ability to melt glass leads to wave guide writing. The potential applications of laser filamentation in atmospheric sensing and the generation of other electromagnetic pulses from the UV to the radio frequency are treated, together with possible future challenges in the excitation of super-excited states of molecules. Exciting new phenomena such as filament induced ultrafast birefringence and the excitation of molecular rotational wave packets and their multiple revivals in air (gases) will also ...

  10. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

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


    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...

  11. Laser controlled flame stabilization (United States)

    Early, James W.; Thomas, Matthew E.


    A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.

  12. Auricular Acupuncture with Laser (United States)

    Bahr, Frank


    Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies. PMID:23935695

  13. NASA Space Laser Technology (United States)

    Krainak, Michael A.


    Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

  14. Teradiode's high brightness semiconductor lasers (United States)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz


    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, world-record brightness levels for direct diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  15. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)


    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  16. Laser autodyne angioscopy (United States)

    Gordov, Eugeni P.; Makogon, Michail M.; Pekarskii, Vikentii V.; Shipulin, Vladimir M.


    A novel approach to imagination of inner surface of arteria during performing laser and balloon angioplasty is suggested. To this end the laser light was transmitted via fiber to the zone of interest and radiation diffused by the walls of the vessel was adopted by receiver. Known technique to determine of contours of an object by measuring the time of the laser pulse propagation is unusable due to the small geometrical scales. Using the CW laser and feeding a portion of the backscattered signal power into the laser cavity (this kind of device was referred to as laser autodyne coherent receiver), the authors have been able to measure the object contour with spatial resolution of up to 2 microns. Such resolution and high sensitivity inherent to this technique should allows one to detect early in the development of the atherosclerosis. To obtain the 3D image of the vessel inside surface we offer two methods. In the first case the vessel side is scanned by moving the end of light quid. In the second one multimode laser is used and the image is drawing by scanning the transverse modes of this laser. The vessel side and atherosclerotic plaques have the different reflectivity spectrum and this fact can be used to increase the image contrast. The correct selection of the laser wavelength makes possible to work into the vessel with circulation of the blood. The calculation of laser autodyne intrascope performance and tentative experimental results are presented in this report. The advantages of this method for the angiography are in speed and adequately of control during performing angioplasty.

  17. Comparative shock wave analysis during corneal ablation with an excimer laser, picosecond laser, and femtosecond laser (United States)

    Krueger, Ronald R.; Juhasz, Tibor


    With the event of topographic steep central islands following excimer laser surgery and the potential damage to the corneal endothelium, shock waves are playing an increasingly important role in laser refractive surgery. With this in mind, we performed a comparative shock wave analysis in corneal tissue using an excimer laser, picosecond laser, and femtosecond laser. We used a Lambda Physik excimer laser at 308 nm wavelength, a Nd:YLF picosecond laser at 1053 nm wavelength and a synchronously pumped linear cavity femtosecond laser at 630 nm wavelength. The pulse widths of the corresponding lasers were 8 ns, 18 ps, 150 fs, respectively. The energy density of irradiation was 2.5 to 8 times the threshold level being 2 J/cm2 (excimer laser), 86 J/cm2 (picosecond laser) and 10.3 J/cm2 (femtosecond laser). Shock wave dynamics were analyzed using time-resolved photography on a nanosecond time scale using the picosecond laser in corneal tissue, water and air. Shock wave dynamics using the femtosecond laser were studied in water only while the excimer laser induced shock wave during corneal ablation was studied in air only. We found the dynamics of shock waves to be similar in water and corneal tissue indicating that water is a good model to investigate shock wave effects in the cornea. The magnitude of the shock wave velocity and pressure decays over time to that of a sound wave. The distance over which it decays is 3 mm in air with the excimer laser and 600 - 700 micrometers in air with the picosecond laser. In water, the picosecond laser shock wave decays over a distance of 150 micrometers compared to the femtosecond laser shock wave which decays over a distance of 30 micrometers . Overall the excimer laser shock wave propagates 5 times further than that of the picosecond laser and the picosecond laser shock wave propagates 5 times further than that of the femtosecond laser. In this preliminary comparison, the time and distance for shock wave decay appears to be directly

  18. Direct Laser Acceleration in Laser Wakefield Accelerators (United States)

    Shaw, J. L.; Froula, D. H.; Marsh, K. A.; Joshi, C.; Lemos, N.


    The direct laser acceleration (DLA) of electrons in a laser wakefield accelerator (LWFA) has been investigated. We show that when there is a significant overlap between the drive laser and the trapped electrons in a LWFA cavity, the accelerating electrons can gain energy from the DLA mechanism in addition to LWFA. The properties of the electron beams produced in a LWFA, where the electrons are injected by ionization injection, have been investigated using particle-in-cell (PIC) code simulations. Particle tracking was used to demonstrate the presence of DLA in LWFA. Further PIC simulations comparing LWFA with and without DLA show that the presence of DLA can lead to electron beams that have maximum energies that exceed the estimates given by the theory for the ideal blowout regime. The magnitude of the contribution of DLA to the energy gained by the electron was found to be on the order of the LWFA contribution. The presence of DLA in a LWFA can also lead to enhanced betatron oscillation amplitudes and increased divergence in the direction of the laser polarization. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. History and principle of lasers; Histoire et principe des lasers

    Energy Technology Data Exchange (ETDEWEB)

    Townes, Ch.H. [Universite de Californie, Berkeley (United States); Schwob, C. [Institut de Nanosciences de Paris, UPMC/CNRS, 75 - Paris (France); Julien, L. [Lab. Kastler Brossel ENS/UPMC/CNRS, 75 - Paris (France); Forget, S. [Lab. de Physique des Lasers, Paris-13 Univ., 93 - Villetaneuse (France); Robert-Philip, I. [Lab. de Photonique et de anostructures, CNRS, 91 - Marcoussis (France); Balcou, Ph. [Centre des lasers Intenses et Applications, Bordeaux-1 Univ., 33 - Talence (France)


    This document gathers 3 short articles: in the first one, C.H. Townes, the inventor of the laser, presents the genesis of the laser, while the principle of the laser is described in the second and the different types of lasers are reviewed in the third. The most important technological progress is expected in ultra-intense lasers that will be used in inertial fusion in gigantic facilities

  20. [Lasers in dentistry 1. What is special about lasers?]. (United States)

    ten Bosch, J J


    Diagnosis and treatment with lasers is becoming widely spread in dentistry. This article is an introduction to a series of articles that deal with the many dental applications of lasers. The article contains a summary of presently used lasers. It also describes the pertinent features of laser radiation: parallelism of the beam and narrow line shape in the spectrum of electromagnetic radiation. Finally, it summarizes the relevant processes of interaction of laser radiation with tissue: scattering, absorption, fluorescence and frequency-doubling.

  1. 1982 laser program annual report

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, C.D.; Grow, G.R. (eds.)


    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

  2. Femtosecond petawatt laser

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Tae Moon; Lee, Jongmin [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (Korea, Republic of)


    The high-power femtosecond laser has now become an excellent scientific tool for the study of not only relativistic laser-matter interactions but also scientific applications. The high-power femtosecond laser depends on the Kerr-lens modelocking (KLM) and chirped-pulse amplification (CPA) technique. An all-Ti:sapphire-based 30-fs PW CPA laser, which is called the PULSER (Petawatt Ultrashort Laser System for Extreme Science Research) has been recently constructed and is being used for accelerating the charged particles (electrons and protons) and generating ultrashort high-energy photon (X-ray and γ-ray) sources. In this review, the world-wide PW-level femtosecond laser systems are first summarized, the output performances of the PULSER-I and II are described, and the future upgrade plan of the PULSER to the multi-PW level is also discussed. Then, several experimental results on particle (electron and proton) acceleration and X-ray generation in the intensity range of mid-10{sup 18} W/cm{sup 2} to mid-10{sup 20} W/cm{sup 2} are described. Experimental demonstrations for the newly proposed phenomena and the understanding of physical mechanisms in relativistic and ultrarelativistic regimes are highly expected as increasing the laser peak intensity up to over 10{sup 22} W/cm{sup 2} ∝10{sup 23} W/cm{sup 2}. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Laser scar revision. (United States)

    Lupton, Jason R; Alster, Tina S


    A variety of lasers can be used to treat scars and striae effectively. It is of paramount importance that the type of scar be properly classified on initial examination so that the most appropriate method of treatment can be chosen. Classification also allows the laser surgeon to discuss with the patient the anticipated response to treatment. The 585-nm pulsed dye laser (PDL) is the most appropriate system for treating hypertrophic scars, keloids, erythematous scars, and striae. The PDL carries a low risk of side effects and complications when operated at appropriate treatment parameters and time intervals. Atrophic scars are best treated with ablative CO2 and Er:YAG lasers; however, proliferative keloids and hypertrophic scars should not be vaporized because of the high risk of scar recurrence or progression. The appropriate choice and use of lasers can significantly improve most scars. As research in laser-skin interaction continues, further refinements in laser technology coupled with the addition of alternate treatment procedures will allow improved clinical efficacy and predictability.

  4. Novel laser ion sources

    CERN Document Server

    Fournier, P; Kugler, H; Lisi, N; Scrivens, R; Rodríguez, F V; Düsterer, S; Sauerbrey, R; Schillinger, H; Theobald, W; Veisz, L; Tisch, J W G; Smith, R A


    Development in the field of high-power laser systems with repetition rates of several Hz and energies of few joules is highly active and opening, giving new possibilities for the design of laser ions sources. Preliminary investigations on the use of four different laser and target configurations are presented: (1) A small CO/sub 2/ laser (100 mJ, 10.6 mu m) focused onto a polyethylene target to produce C ions at 1 Hz repetition rate (CERN). (2) An excimer XeCl laser (6 J, 308 nm) focused onto solid targets (Frascati). (3) A femtosecond Ti: sapphire laser (250 mJ, 800 nm) directed onto a solid targets (Jena). (4) A picosecond Nd: yttrium-aluminum-garnet (0.3 J, 532 nm) focused into a dense medium of atomic clusters and onto solid targets (London). The preliminary experimental results and the most promising schemes will be discussed with respect to the scaling of the production of high numbers of highly charged ions. Different lasers are compared in terms of current density at 1 m distance for each charge state...

  5. Ultra-intense lasers

    CERN Document Server

    Mourou, G


    This article reviews the applications of ultra-intense lasers in domains like particle acceleration, gamma-gamma collisions, cancer diagnostic, eye surgery and inertial fusion. The main characteristic of such lasers is to deliver impulses carrying the same amount of energy as did previous generations of lasers but in a far shorter time which increases their power dramatically. Typically an ultra-intense laser releases 1 joule through an impulse that lasts 100 femtoseconds which means a power of 10 sup 1 sup 3 Watt. The method of the amplification of impulses through frequency shift (CPA) has allowed power lasers to reach power levels that were beyond the technological limits of amplifying equipment (10 sup 9 W). The powerful electrical field of a femtosecond laser impulse make electrons oscillate with speeds nearing the speed of light while its magnetic field accelerates them in the perpendicular direction of the oscillation plane. Ultra-intense lasers generate electric fields from 10 sup 1 sup 2 to 10 sup 1 ...

  6. Color Laser Microscope (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.


    A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

  7. Dye laser principles with applications

    CERN Document Server

    Duarte, Frank J; Liao, Peter F; Kelley, Paul


    A tutorial introduction to the field of dye lasers, Dye Laser Principles also serves as an up-to-date overview for those using dye lasers as research and industrial tools. A number of the issues discussed in this book are pertinent not only to dye lasers but also to lasers in general. Most of the chapters in the book contain problem sets that expand on the material covered in the chapter.Key Features* Dye lasers are among the most versatile and successful laser sources currently available in use Offering both pulsed and continuous-wave operation and tunable from the near ultraviole

  8. Color speckle in laser displays (United States)

    Kuroda, Kazuo


    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  9. Organic solid-state lasers

    CERN Document Server

    Forget, Sébastien


    Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

  10. Physics of semiconductor laser devices

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, G.H.B.


    Aspects of laser design and development are considered along with semiconductor materials for lasers, problems of device fabrication, crystal growth, the degradation of lasers, and the integration of semiconductor lasers with other optical components. A description is presented of light emission processes and laser action in semiconductors, taking into account electronic radiative transitions, the relation between emission and absorption processes, transition probabilities, the density of electron states in the highly doped semiconductor, carrier recombination and spontaneous emission, the gain/current relation, light-current characteristics, optical modes, and the evolution of mode spectrum and intensity with current. Attention is given to laser heterostructures and the properties of heterojunctions, optical waveguides, the performance of heterostructure lasers, stripe geometry lasers, and the dynamic response of lasers. Lasers with distributed feedback and Bragg reflectors are also discussed.

  11. Monoenergetic laser wakefield acceleration

    Directory of Open Access Journals (Sweden)

    N. E. Andreev


    Full Text Available Three dimensional test particle simulations are applied to optimization of the plasma-channeled laser wakefield accelerator (LWFA operating in a weakly nonlinear regime. Electron beam energy spread, emittance, and luminosity depend upon the proportion of the electron bunch size to the plasma wavelength. This proportion tends to improve with the laser wavelength increase. We simulate a prospective two-stage ∼1GeV LWFA with controlled energy spread and emittance. The input parameters correspond to realistic capabilities of the BNL Accelerator Test Facility that features a picosecond-terawatt CO_{2} laser and a high-brightness electron gun.

  12. Lasers In Dental Diagnosis (United States)

    Everse, K. E.; Sinor, T. W.; Menzel, E. R.


    We have investigated the potential of lasers for real time in situ dental diagnosis via transillumination of teeth and gums and via fluorescence. Not surprisingly, absorption and/or scattering of light by teeth was found to be insensitive to light color. However, monochromatic transillumination revealed detail better than white light. Transillumination of gums was best performed with orange-red light because of tissue absorption. Illumination of oral structures by 488 nm Ar-laser light was effective in revealing diagnosis detail by fluorescence. Incipient caries and fine tooth fracture lines that are generally not revealed by radiography were observable by laser.

  13. Laser undulator radiation

    CERN Document Server

    Kawamura, Y; Ruschin, S; Tanabé, T; Toyoda, K


    Various characteristics such as the number of photons, the wavelength, and the solid angle of the laser undulator radiation have been measured quantitatively. It was performed in the visible wavelength region using the interaction between a high-power pulsed CO sub 2 laser and a high-quality electron beam having an energy of 0.65-0.85 MeV. The experimental results were in good agreement with the theoretical calculations. A criterion to determine the limitation to the number of periods of the laser undulator was also proposed.

  14. Optimising laser tattoo removal

    Directory of Open Access Journals (Sweden)

    Kabir Sardana


    Full Text Available Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal.

  15. Optimising Laser Tattoo Removal (United States)

    Sardana, Kabir; Ranjan, Rashmi; Ghunawat, Sneha


    Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal. PMID:25949018

  16. Laser propulsion: a review

    CSIR Research Space (South Africa)

    Michaelis, MM


    Full Text Available is that the Crookes radiometer rotates due to photon rather than gas pressure. In fact, the very first pure photon pendulum experiment was carried out by American laser propulsion enthusiasts Myrabo, Knowles, Bagford, Siebert and Harris.31 The photon pressure... is minute: the photon force on a 10-cm2 target illuminated by a 9-kW CO2 laser is found from: hence the need for an ultra-delicate pendulum equipment, as well as for a high-power laser source! In marked contrast to the Myrabo experiment...

  17. Laser in manufacturing

    CERN Document Server

    Davim, J Paulo


    Generally a laser (light amplification by stimulated emission of radiation) is defined as "a device which uses a quantum mechanical effect, stimulated emission, to generate a coherent beam of light from a lasing medium of controlled purity, size, and shape". Laser material processing represents a great number of methods, which are rapidly growing in current and different industrial applications as new alternatives to traditional manufacturing processes. Nowadays, the use of lasers in manufacturing is an emerging area with a wide variety of applications, for example, in electronics, molds an

  18. Ultrashort Laser Pulse Phenomena

    CERN Document Server

    Diels, Jean-Claude


    Ultrashort Laser Pulse Phenomena, 2e serves as an introduction to the phenomena of ultra short laser pulses and describes how this technology can be used to examine problems in areas such as electromagnetism, optics, and quantum mechanics. Ultrashort Laser Pulse Phenomena combines theoretical backgrounds and experimental techniques and will serve as a manual on designing and constructing femtosecond (""faster than electronics"") systems or experiments from scratch. Beyond the simple optical system, the various sources of ultrashort pulses are presented, again with emphasis on the basic

  19. Laser applications in neurosurgery (United States)

    Cerullo, Leonard J.


    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  20. Pyrometry applications in laser machining (United States)

    Smurov, Igor


    Special techniques of non-contact optical diagnostics under actual industrial conditions is required for accurate temperature monitoring and control in a wide range of laser applications. The set of pyrometers was developed and applied for surface temperature monitoring in pulsed periodic Nd:YAG laser welding and surface treatment, deep penetration welding by CO2 and Nd:YAG lasers, and electron beam; laser assisted machining; laser cladding, etc.

  1. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman


    This book introduces model studies and experimental results associated with laser forming and welding such as laser induced bending, welding of sheet metals, and related practical applications. The book provides insight into the physical processes involved with laser forming and welding. The analytical study covers the formulation of laser induced bending while the model study demonstrates the simulation of bending and welding processes using the finite element method. Analytical and numerical solutions for laser forming and welding problems are provided.

  2. [Experimental and clinical experiences with bronchologic lasers]. (United States)

    Knoth, E; Wiesner, B; Dürschmied, H


    Bronchological application of lasers is based on differences of their biophysical effects, which were confirmed in experimental investigations. There were early reepithelizations and rapid healing after laser tracheotomy and lung resections without signs secondary stenoses by hypergranulation. Argon laser is of limited use in bronchology for HpD-coupled tumor fluorescence diagnostic. Nd-YAG-laser is the "classic" laser for palliative bronchial tumor therapy. Improvements of laser applications (laser thoracoscopy, perthoracic laser punction therapy) are new therapeutic laser methods.

  3. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...

  4. Jupiter Laser Facility (United States)

    Federal Laboratory Consortium — The Jupiter Laser Facility is an institutional user facility in the Physical and Life Sciences Directorate at LLNL. The facility is designed to provide a high degree...

  5. Foundations of laser spectroscopy

    CERN Document Server

    Stenholm, Stig


    A simple presentation of the theoretical foundations of steady-state laser spectroscopy, this text helps students to apply theory to calculations with a systematic series of examples and exercises. 1984 edition.

  6. Beamlet laser diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Burkhart, S.C.; Behrendt, W.C.; Smith, I.


    Beamlet is instrumented extensively to monitor the performance of the overall laser system and many of its subsystems. Beam diagnostics, installed in key locations, are used to fully characterize the beam during its propagation through the multipass cavity and the laser`s output section. This article describes the diagnostics stations located on Beamlet and discusses the design, calibration, and performance of the Beamlet calorimeters. The authors used Nova`s diagnostics packages to develop the Beamlet design to determine beam energy, spatial profile, temporal profile, and other beam parameters. Technologic improvements within the last several years in controls, charge-coupled device (CCD) cameras, and fast oscilloscopes have allowed the authors to obtain more accurate measurements on the Beamlet laser system. They briefly cover some of these techniques, including a description of their LabVIEW based data acquisition system.

  7. Laser Guidance Analysis Facility (United States)

    Federal Laboratory Consortium — This facility, which provides for real time, closed loop evaluation of semi-active laser guidance hardware, has and continues to be instrumental in the development...

  8. Excimer Laser Etching

    Energy Technology Data Exchange (ETDEWEB)

    Boatner, Lynn A [ORNL; Longmire, Hu Foster [ORNL; Rouleau, Christopher M [ORNL; Gray, Allison S [ORNL


    Excimer laser radiation at a wavelength of = 248 nm represents a new etching method for the preparation of metallographic specimens. The method is shown to be particularly effective for enhancing the contrast between different phases in a multiphase metallographic specimen.

  9. Compact semiconductor lasers

    CERN Document Server

    Yu, Siyuan; Lourtioz, Jean-Michel


    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  10. Lasers and optical engineering

    CERN Document Server

    Das, P


    A textbook on lasers and optical engineering should include all aspects of lasers and optics; however, this is a large undertaking. The objective of this book is to give an introduction to the subject on a level such that under­ graduate students (mostly juniors/seniors), from disciplines like electrical engineering, physics, and optical engineering, can use the book. To achieve this goal, a lot of basic background material, central to the subject, has been covered in optics and laser physics. Students with an elementary knowledge of freshman physics and with no formal courses in electromagnetic theory should be able to follow the book, although for some sections, knowledge of electromagnetic theory, the Fourier transform, and linear systems would be highly beneficial. There are excellent books on optics, laser physics, and optical engineering. Actually, most of my knowledge was acquired through these. However, when I started teaching an undergraduate course in 1974, under the same heading as the title of th...

  11. Erbium lasers in dentistry. (United States)

    van As, Glenn


    Erbium hard tissue lasers have the capability to prepare enamel, dentin, caries, cementum, and bone in addition to cutting soft tissue. The ability of hard tissue lasers to reduce or eliminate vibrations, the audible whine of drills, microfractures, and some of the discomfort that many patients fear and commonly associate with high-speed handpieces is impressive. In addition, these lasers can be used with a reduced amount of local anesthetic for many procedures. Today, these instruments have evolved from their initial use for all classes of cavity preparations to their ability for removing soft tissue, their usefulness in the disinfection of bacteria within endodontic canals, and most recently, as an alternative to the high speed handpiece for the removal of bone in oral and maxillofacial surgery. In addition, recent research has centered on the value of the erbium family of laser wavelengths in periodontics, including the removal of calculus.

  12. Laser therapy for periodontitis (United States)

    Efanov, O. I.


    An investigation was made of applying pulsed (lambda) equals 0.89 micrometers laser radiation in the treatment for early diagnosed periodontitis. The investigation was made on 65 patients (47 patients constituted the experimental group and 18 patients constituted a control group) affected by periodontitis. Clinical and functional tests revealed that laser therapy produced a string effect on the course of the illness. It reduced bleeding, inflammation, and pruritus. However, it did not produce an affect on electroexcitation. Biomicroscopic examinations and periodontium rheography revealed that the gingival blood flow became normal after the course of laser therapy. The capillary permeability and venous congestion decreased, which was confirmed by the increased time of vacuum tests, raised gingival temperature, reduced tissue clearance, and increased oxygen tension. Apart from that, laser therapy subsided fibrinolysis, proteolytic tissue activity, and decreased the exudative inflammation of periodontium.

  13. Lasers in dental traumatology. (United States)

    Olivi, G; Caprioglio, C; Genovese, M D


    Dental traumas are frequent in children. They can be complex events and sometimes real emergencies. Since very little attention is devoted to this topic in the international literature and there are no well-coded laser guidelines for these specific clinical events, our aim is to consider and present those situations in which laser-assisted therapy can offer new treatment possibilities. The authors' aim is to stimulate more extensive scientific research in this area, which might not only increase the use of these technologies, but also improve outcomes and reduce complications connected to dental trauma, particularly in children. Furthermore, laser-assisted therapies drastically reduce the need for analgesics and anti- inflammatory medications compared with conventional procedures. Using laser equipment to obtain anaesthesia is another challenge, while the use of low power setting for desensitising tissue and to obtain anaesthesia is also an open field.

  14. [Lasers in dentistry. Epilogue]. (United States)

    ten Bosch, J J


    Laser use in the dental clinic requires scientifically demonstrated improvement for patient and/or dentist, easily obtainable equipment, adequate training and safety. These aspects are summarized for all laser applications. Improvement has not been shown for all applications. In the Netherlands manufacturer-independent training is little available. Safety requires care, but not a large investment. Economical aspects include an adequate compensation for the necessary investment. For only a few applications laser treatment leads to decreased cost or time of treatment. However, also increased compensation by insurers or patients may be possible; some patients will be willing to pay more when laser treatment is less unpleasant than traditional treatment or, in the case of diagnosis, leads to better information.

  15. Lasers in aesthetic dentistry. (United States)

    Adams, Timothy C; Pang, Peter K


    This article focuses on lasers and aesthetic dentistry and their unique parallel in history from their early development to their present day usage and application. The demand for aesthetic dentistry has had a major impact not only on treatment planning but also on the choice of materials, techniques, and equipment. It is this demand that has married the use of lasers with aesthetic dentistry. A short literature review on the five basic laser types precedes the basic premise of smile design and its critical importance in attaining the desirable aesthetic end result. A short review on biologic width and biologic zone reinforces their importance when manipulating gingival tissue. Four case reports highlight the use of diode, erbium, and carbon dioxide lasers. The end results show the power of proper treatment planning and the use of a smile design guide when using these instruments and confirm a conservative, aesthetic treatment without compromising the health and function of the patients.

  16. Electra Laser Facility (United States)

    Federal Laboratory Consortium — FUNCTION: The Electra Laser Facility is used to develop the science and technology needed to develop a reliable, efficient, high-energy, repetitively pulsed krypton...

  17. Paint removal using lasers. (United States)

    Liu, K; Garmire, E


    Experiments to investigate the potential for practical laser graffiti-removal systems are reported. A universal engineering curve for the time needed for removal of paint from nonconductive substrates that was valid over a range of 10(7) in intensity was measured with a variety of lasers. Comparable times were measured for conductive substrates, when pulses shorter than the thermal conduction times were used. Analysis suggests that Q-switched Nd:YAG lasers may be the most efficient means for removing graffiti and other unwanted paint. An 1-m(2) area of paint 14 µm thick can be removed in approximately 10 min with a 50-Hz laser system of 15-W average power.

  18. Lasers and holography

    CERN Document Server

    Kock, Winston E


    Accessible, illustrated introduction covers wave patterns and coherence, summarizes the development of lasers and the phenomenon of wave diffraction, and describes zone plates and properties of holograms. 1981 edition.

  19. Airclad fiber laser technology

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes


    High-power fiber lasers and amplifiers have gained tremendous momentum in the last five years, and many of the traditional manufactures of gas and solid-state lasers are pursuing the attractive fiber-based systems, which are now displacing the old technology in many areas. High-power fiber laser...... systems require specially designed fibers with large cores and good power handling capabilities - requirements that are all met by the airclad fiber technology. In the present paper we go through many of the building blocks needed to build high-power systems and we show an example of a complete airclad...... laser system. We present the latest advancements within airclad fiber technology including a new 70 μm single-mode polarization-maintaining rod-type fiber capable of amplifying to MW power levels. Furthermore we describe the novel airclad based pump combiners and their use in a completely monolithic 350...

  20. Airclad fiber laser technology

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes


    High-power fiber lasers and amplifiers have gained tremendous momentum in the last 5 years. Many of the traditional manufacturers of gas and solid-state lasers are now pursuing the fiber-based systems, which are displacing the conventional technology in many areas. High-power fiber laser systems...... require reliable fibers with large cores, stable mode quality, and good power handling capabilities-requirements that are all met by the airclad fiber technology. In the present paper we go through many of the building blocks needed to build high-power systems and we show an example of a complete airclad...... laser system. We present the latest advancements within airclad fiber technology including a new 100 m single-mode polarization-maintaining rod-type fiber capable of amplifying to megawatt power levels. Furthermore, we describe the novel airclad-based pump combiners and their use in a completely...

  1. Blackbody metamaterial lasers

    KAUST Repository

    Liu, Changxu


    We investigate both theoretically and experimentally a new type of laser, which exploits a broadband light "condensation" process sustained by the stimulated amplification of an optical blackbody metamaterial. © 2014 Optical Society of America.

  2. High-energy molecular lasers self-controlled volume-discharge lasers and applications

    CERN Document Server

    Apollonov, V V


    This book displays the physics and design of high-power molecular lasers. The lasers described are self-controlled volume-discharge lasers. The book explains self-sustained discharge lasers, self-initiated discharge lasers and technical approaches to laser design. Important topics discussed are laser efficiency, laser beam quality and electric field homogeneity. The book contains many new innovative applications.

  3. Verification of a characterization method of the laser-induced selective activation based on industrial lasers

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; Tang, Peter T.


    In this article, laser-induced selective activation (LISA) for subsequent autocatalytic copper plating is performed by several types of industrial scale lasers, including a Nd:YAG laser, a UV laser, a fiber laser, a green laser, and a short pulsed laser. Based on analysis of all the laser-machine...

  4. Laser Processed Heat Exchangers (United States)

    Hansen, Scott


    The Laser Processed Heat Exchanger project will investigate the use of laser processed surfaces to reduce mass and volume in liquid/liquid heat exchangers as well as the replacement of the harmful and problematic coatings of the Condensing Heat Exchangers (CHX). For this project, two scale unit test articles will be designed, manufactured, and tested. These two units are a high efficiency liquid/liquid HX and a high reliability CHX.

  5. Laser cooling of solids

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, Richard I [Los Alamos National Laboratory; Sheik-bahae, Mansoor [UNM


    We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

  6. Laser space propulsion overview (United States)

    Phipps, Claude; Luke, James; Helgeson, Wesley


    In this paper, we review the history of laser space propulsion from its earliest theoretical conceptions to modern practical applicatons. Applications begin with the "Lightcraft" flights of Myrabo and include practical thrusters for satellites now completing development as well as proposals for space debris removal and direct launch of payloads into orbit. We consider laser space propulsion in the most general sense, in which laser radiation is used to propel a vehicle in space. In this sense, the topic includes early proposals for pure photon propulsion, laser ablation propulsion, as well as propulsion using lasers to detonate a gas, expel a liquid, heat and expel a gas, or even to propagate power to a remote conventional electric thruster. We also discuss the most recent advances in LSP. For the first time, it is possible to consider space propulsion engines which exhibit thrust of one to several newtons while simultaneously delivering 3,000 seconds, or greater, specific impulse. No other engine concept can do both in a compact format. These willl use onboard, rather than remote, lasers. We will review the concept of chemically augmented electric propulsion, which can provide overall thrust efficiency greater than unity while maintaining very low mass to power ratio, high mean time to failure and broad operating range. The main advantage of LSP is exhaust velocity which can be instantaneously varied from 2km/s to 30km/s, simply by varying laser pulsewidth and focal spot size on target. The laser element will probably be a diode-pumped, fiber master-oscillator-power-amplifier (MOPA) system. Liquid fuels are necessary for volumetric efficiency and reliable performance at the multi-kW optical power levels required for multi-N thrust.

  7. Laser Journal (Selected Articles), (United States)


    comparision on the ovary function of a sterile patient due to inflammation of related organs and on the state and fertility of the animal ovary. It is...Lightbulb Factory, Xinhu Glass Factory, etc. A clinical application based on animal tests has yielded some results, especially for treating diseases...Zhang Yifan Wang Yi Pan Zheng (Laser Laboratory, Shanghai Sailor’s Hospital) We used a HeNe laser in acupuncture for patients with neural double

  8. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper


    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  9. Lasers in pediatric dentistry. (United States)

    Kotlow, Lawrence A


    Pediatric dentistry's mission in delivering care to our young patients is simple: provide optimal preventive, interceptive, and restorative dental care in a stress-free environment. Lasers such as argon, diode, Nd:YAG, CO2, and now the erbium family enable minimally invasive dentistry for hard- and soft-tissue procedures. This article offers an understanding of treatment planning in the pediatric practice and demonstrates the procedures that dental lasers can perform on younger patients.

  10. Insulator for laser housing (United States)

    Duncan, David B.


    The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member.

  11. Laser Initiated Actuator study

    Energy Technology Data Exchange (ETDEWEB)

    Watson, B.


    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.


    African Journals Online (AJOL)

    9 mai 2013 ... Les complications post opératoires étaient rares (1 cas). Conclusion : : Le Laser n'est qu'un instrument qu'on ... toujours été respectées pour éviter les accidents. RÉSULTATS. L'âge moyen était de 34 ans. ... Fin de l'intervention. Fig. 2 : Vue endoscopique per opératoire : Cordectomie postérieure au Laser.

  13. Ceramic Laser Materials

    Energy Technology Data Exchange (ETDEWEB)

    Soules, T F; Clapsaddle, B J; Landingham, R L; Schaffers, K I


    Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally because transparent ceramics afford much greater flexibility in the design of lasers, we have been exploring the potential for much larger apertures, new materials, for example for the Mercury laser, other designs for SSHL, such as, edge pumping designs, slabs with built in ASE suppression, etc. This work has just beginning.

  14. Femtosecond laser materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, B. C., LLNL


    Femtosecond lasers enable materials processing of most any material with extremely high precision and negligible shock or thermal loading to the surrounding area Applications ranging from drilling teeth to cutting explosives to making high-aspect ratio cuts in metals with no heat-affected zone are made possible by this technology For material removal at reasonable rates, we developed a fully computer-controlled 15-Watt average power, 100-fs laser machining system.

  15. Competition Effects in Lasers. (United States)


    Laser", L. Mandel, in Optica Hoy Y Manana-ICO-ll, eds. J. Bescos, A. Hidalgo, L. Plaza and J. Santamaria ( Sociedad Espanola de Optica, Madrid, 1979) pp...previously derived equations for two-mode lasers. 24. " Inversion Problem in Photon Counting with Dead Time", L. Mandel, J. Opt. Soc. Am. 70, 873-874 (1980...temporal variation of atomiz inversion on the fluctuation proper- ties have been investigated in the coherent state diagonal representation of the

  16. Laser therapy for onychomycosis. (United States)

    Gupta, Aditya K; Simpson, Fiona C


    Laser therapy is a rapidly expanding new treatment modality for onychomycosis. To review current and prospective laser systems for the treatment of onychomycosis. We searched the PubMed database, the Food and Drug Administration 510(k) database,, and Google Scholar for in vitro studies, peer-reviewed clinical trials, manufacturers' white papers, and registered clinical trials of laser systems indicated for the treatment of onychomycosis. All published clinical trials were assessed on a 20-point methodological quality scale. We identified three basic science articles, five peer-reviewed articles, three white papers, and four pending clinical trials, as well as numerous gray literature documents. The overall methodological score for the clinical trials was 9.1 ± 1.1, with peer-reviewed studies showing a higher score (9.8 ± 1.5) than white papers (7.5 ± 0.7). We also identified 11 commercial laser device systems of varying global availability. Laser therapy has been tested and approved as a cosmetic treatment only for onychomycosis. It cannot be recommended as a therapeutic intervention to eradicate fungal infection at this time as more rigorous randomized, controlled trials are required to determine if laser therapy is efficacious on par with oral and topical interventions.

  17. Laser prostate enucleation techniques. (United States)

    Lerner, Lori B; Rajender, Archana


    Laser treatment of benign prostatic hyperplasia (BPH) through enucleation techniques has become increasingly more utilized in the field of urology. Laser enucleation of the prostate (LEP) is a transurethral procedure that employs several different types of lasers to dissect the adenoma from the surgical capsule in a retrograde fashion. We review basic laser physics and current laser prostate enucleation techniques. Holmium-LEP (HoLEP), Thulium-LEP (ThuLEP), Greenlight-LEP (GreenLEP) and Diode-LEP (DiLEP) applications are discussed. We summarize the current literature with respect to functional outcomes and complications. Although each laser device used for prostate enucleation has the same goal of removal of the adenoma from the surgical capsule, each has unique characteristics (i.e. wavelength, absorption rates) that must be understood by the practicing surgeon. Mastery of one LEP technique does not necessarily translate into facile use of an alternative enucleation energy source and/or approach. The various LEP techniques have demonstrated similar, if not superior, postoperative results to transurethral resection of the prostate (TURP), the current gold standard in the treatment of BPH. This article outlines the current LEP techniques and should serve as a quick reference for the practicing urologist.

  18. Underwater laser detection system (United States)

    Gomaa, Walid; El-Sherif, Ashraf F.; El-Sharkawy, Yasser H.


    The conventional method used to detect an underwater target is by sending and receiving some form of acoustic energy. But the acoustic systems have limitations in the range resolution and accuracy; while, the potential benefits of a laserbased underwater target detection include high directionality, high response, and high range accuracy. Lasers operating in the blue-green region of the light spectrum(420 : 570nm)have a several applications in the area of detection and ranging of submersible targets due to minimum attenuation through water ( less than 0.1 m-1) and maximum laser reflection from estimated target (like mines or submarines) to provide a long range of detection. In this paper laser attenuation in water was measured experimentally by new simple method by using high resolution spectrometer. The laser echoes from different targets (metal, plastic, wood, and rubber) were detected using high resolution CCD camera; the position of detection camera was optimized to provide a high reflection laser from target and low backscattering noise from the water medium, digital image processing techniques were applied to detect and discriminate the echoes from the metal target and subtract the echoes from other objects. Extraction the image of target from the scattering noise is done by background subtraction and edge detection techniques. As a conclusion, we present a high response laser imaging system to detect and discriminate small size, like-mine underwater targets.

  19. Laser radiation bracket debonding (United States)

    Dostálová, Tat'jana; Jelínková, Helena; Šulc, Jan; Koranda, Petr; Nemec, Michal; Racek, Jaroslav; Miyagi, Mitsunobu


    Ceramic brackets are an aesthetic substitute for conventional stainless steel brackets in orthodontic patients. However, ceramic brackets are more brittle and have higher bond strengths, which can lead to bracket breakage and enamel damage during classical type of debonding. This study examined the possibility of laser radiation ceramic brackets removing as well as the possible damage of a surface structure of hard dental tissue after this procedure. Two types of lasers were used for the experiments - a laser diode LIMO HLU20F400 generating a wavelength of 808 nm with the maximum output power 20W at the end of the fiber (core diameter 400 μm, numerical aperture 0.22). As a second source, a diode-pumped Tm:YAP laser system generating a wavelength of 1.9 μm, with up to 3.8 W maximum output power was chosen. For the investigation, extracted incisors with ceramic brackets were used. In both cases, laser radiation was applied for 0.5 minute at a maximum power of 1 W. Temperature changes of the irradiated tissue was registered by camera Electrophysics PV320. After the interaction experiment, the photo-documentation was prepared by the stereomicroscope Nikon SMZ 2T, Japan. The surface tissue analysis was processed in "low vacuum" (30 Pa) regime without desiccation. This technique was used to record back-scattered electron images. Selecting the appropriate laser, resin, and bracket combination can minimize risks of enamel degradation and make debonding more safe.

  20. CO2 laser cutting

    CERN Document Server

    Powell, John


    The laser has given manufacturing industry a new tool. When the laser beam is focused it can generate one of the world's most intense energy sources, more intense than flames and arcs, though similar to an electron beam. In fact the intensity is such that it can vaporise most known materials. The laser material processing industry has been growing swiftly as the quality, speed and new manufacturing possibilities become better understood. In the fore of these new technologies is the process of laser cutting. Laser cutting leads because it is a direct process substitu­ tion and the laser can usually do the job with greater flexibility, speed and quality than its competitors. However, to achieve these high speeds with high quality con­ siderable know how and experience is required. This information is usually carefully guarded by the businesses concerned and has to be gained by hard experience and technical understanding. Yet in this book John Powell explains in lucid and almost non­ technical language many o...

  1. Laser Scanning in Forests

    Directory of Open Access Journals (Sweden)

    Håkan Olsson


    Full Text Available The introduction of Airborne Laser Scanning (ALS to forests has been revolutionary during the last decade. This development was facilitated by combining earlier ranging lidar discoveries [1–5], with experience obtained from full-waveform ranging radar [6,7] to new airborne laser scanning systems which had components such as a GNSS receiver (Global Navigation Satellite System, IMU (Inertial Measurement Unit and a scanning mechanism. Since the first commercial ALS in 1994, new ALS-based forest inventory approaches have been reported feasible for operational activities [8–12]. ALS is currently operationally applied for stand level forest inventories, for example, in Nordic countries. In Finland alone, the adoption of ALS for forest data collection has led to an annual savings of around 20 M€/year, and the work is mainly done by companies instead of governmental organizations. In spite of the long implementation times and there being a limited tradition of making changes in the forest sector, laser scanning was commercially and operationally applied after about only one decade of research. When analyzing high-ranked journal papers from ISI Web of Science, the topic of laser scanning of forests has been the driving force for the whole laser scanning research society over the last decade. Thus, the topic “laser scanning in forests” has provided a significant industrial, societal and scientific impact. [...

  2. Laser Ablation for Medical Applications (United States)

    Hayashi, Ken-Ichi

    Medical applications of laser are measurement, laser surgery, in-situ monitoring, and processing of medical devices. In this paper, author briefly reviews the trends of medical applications, describes some new applications, and then discuss about the future trends and problems of medical applications. At present, the domestic market of laser equipment for medical applications is nearly 1/10 of that for industrial applications, which has registered significant growth continuously. Laser surgery as a minimum invasive surgery under arthroscope is expected to decrease the pain of patients. Precise processing such as cutting and welding is suitable for manufacturing medical devices. Pulsed laser deposition has been successfully applied to the thin film coating. The corneal refractive surgery by ArF excimer laser has been widely accepted for its highly safe operation. Laser ablation for retinal implant in the visual prosthesis is one of the promising applications of laser ablation in medicine. New applications with femtosecond laser are expected in the near future.

  3. [Lasers in dentistry 6. The soft laser]. (United States)

    ten Bosch, J J


    A soft laser is a low-power laser emitting in the red and near-infrared part of the spectrum. Studies with cell cultures have shown that radiation from a soft laser, when used under proper conditions, promotes cell function and cell proliferation. However, wavelength and dose should be carefully adjusted to an optimum value: too low a dose does not work and neither does a high dose. The dose should be adjusted within an interval of about 10%. In a few animal studies a positive effect on wound healing has been demonstrated, although other studies did not show such an effect. Of the human studies done in the dental field, many do not meet scientific standards because there was no control group or the study was not double-blind. A few studies showed a positive effect but most did not. Perhaps the large variation in results may be explained by the required accuracy of adjustment of the dose, combined with the complicated processes that relate the incident dose to the dose to cells lying on or in tissue. More research, in particular studies in which the dose and wave length are varied systematically, are needed before responsible clinical use can be recommended.

  4. High precision laser photometer for laser optics (United States)

    Zhao, Yuan'an; Hu, Guohang; Cao, Zhen; Liu, Shijie; Zhu, Meiping; Shao, Jianda


    Development of laser systems requires optical components with high performance, and a high-precision double-beam laser photometer was designed and established to measure the optical performance at 1064nm. Double beam design and lock-in technique was applied to decrease the impact of light energy instability and electric noise. Pairs of samples were placed symmetrically to eliminate beam displacement, and laser scattering imaging technique was applied to determine the influence of surface defect on the optical performance. Based on the above techniques, transmittance and reflection of pairs of optics were obtained, and the measurement precision was improved to 0.06%. Different types of optical loss, such as total loss, volume loss, residual reflection and surface scattering loss, were obtained from the transmittance and reflection measurement of samples with different thickness. Comparison of optical performance of the test points with and without surface defects, the influence of surface defects on optical performance was determined. The optical performance of Nd-glass at 1064nm were measured as an example. Different types of optical loss and the influence of surface defects on the optical loss was determined.

  5. Lasers in endodontics: an overview (United States)

    Frentzen, Matthias; Braun, Andreas; Koort, Hans J.


    The interest in endodontic use of dental laser systems is increasing. Developing laser technology and a better understanding of laser effects widened the spectrum of possible endodontic indications. Various laser systems including excimer-, argon+-, diode-, Nd:YAG-, Er:YAG- and CO2-lasers are used in pulp diagnosis, treatment of hypersensitivity, pulp capping, sterilization of root canals, root canal shaping and obturation or apicoectomy. With the development of new delivery systems - thin and flexible fibers - for many different wavelengths laser applications in endodontics may increase. Since laser devices are still relatively costly, access to them is limited. Most of the clinical applications are laser assisted procedures such as the removing of pulp remnants and debris or disinfection of infected root canals. The essential question is whether a laser can provide improved treatment over conventional care. To perform laser therapy in endodontics today different laser types with adopted wavelengths and pulse widths are needed, each specific to a particular application. Looking into the future we will need endodontic laser equipment providing optimal laser parameters for different treatment modalities. Nevertheless, the quantity of research reports from the last decade promises a genuine future for lasers in endodontics.

  6. Racetrack Mapping: Engaging Students in Mathematics and Geography (United States)

    Tromp, Calvin; Davis, Rob


    This paper reports on a classroom investigation of a sequence of cross-disciplinary mapping lessons undertaken by Grade Five students at Black Hill Primary, a Victorian State Primary School in Ballarat. While this activity was broadly framed around Mathematics, there were also important elements from Geography, (a new emphasis in the Victorian…

  7. Drug contamination of the equine racetrack environment: a preliminary examination. (United States)

    Barker, S A


    Advances in analytical technology now make it feasible to detect and confirm exceptionally low concentrations (pg to fg/mL) of drugs and their metabolites in equine biological fluids. These new capabilities complicate the regulatory interpretation of drug positives and bring into question the fair application of medication rules. Such approaches and policies are further complicated by the possibility that drug positives may arise from contamination of the equine environment on the backstretch of the race track. This manuscript provides data demonstrating that the general environment of the backstretch in which horses live is contaminated with therapeutic drugs and drugs of human origin. The major contaminants are nonsteroidal anti-inflammatory drugs, such as flunixin, phenylbutazone and naproxen, present in the soil in stalls, on stall surfaces, in the dust that circulates and in the lagoon waters that accumulate on the backstretch. The presence of caffeine and cotinine suggest other possible vectors for contamination by humans. Concentrations of these compounds as well as their frequency of occurrence are provided.

  8. Laser safety in the lab

    CERN Document Server

    Barat, Ken L


    There is no more challenging setting for laser use than a research environment. In almost every other setting the laser controls count on engineering controls, and human exposure is kept to a minimum. In research, however, the user often manipulates the optical layout and thereby places him or herself in peril, but this does not mean that accidents and injury are unavoidable. On the contrary, laser accidents can be avoided by following a number of simple approaches. [i]Laser Safety in the Lab[/i] provides the laser user and laser safety officer with practical guidelines from housekeeping to ey

  9. Laser use in veterinary dentistry. (United States)

    Bellows, Jan


    Lasers have been used in human dentistry since the 1960's. Lasers can provide a veterinary dentist access to difficult to reach areas with a relatively bloodless surgical field. Due to vaporization of nerve endings, human patients undergoing laser dental treatment reveal less pain compared to scalpel driven procedures. Dental applications for the commonly used lasers are discussed, as are special safety precautions. Many dental procedures enhanced by a carbon dioxide laser are covered. Future applications for the laser in veterinary dentistry are also discussed.

  10. High power ultrashort pulse lasers

    Energy Technology Data Exchange (ETDEWEB)

    Perry, M.D.


    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced.

  11. Surgical Lasers In Gynecology (United States)

    Schellhas, Helmut F.; Barnes, Alfonso E.


    Multipurpose surgical CO2 lasers marketed in the USA have been developed to be applicable to a variety of surgical procedures in many surgical fields. They are all suited for endoscopic surgical procedures and can be fitted to all standard surgical microscopes. They all can adjust the focal length of the laser beam to the different standard focal lengths of the surgical microscope which for instance in laryngoscopy is 400 mm and in colposcopy 300 mm. One laser instrument can even change the spot size in a given focal distance which is very advantageous for some microsurgical procedures (Merrimack Laboratories 820). All multipurpose surgical CO2 laser systems provide a multi-articulated surgical arm for free-hand surgery. The surgical arms are cumbersome to use but they are adapted to the surgeons needs with ingenuity. The practicality of the multi-articulated surgical arms depends mostly on the distance of the handpiece from the surgical console which now is also overbridged by the laser tube in most surgical laser system. The spot size of the beam is variable in most handpieces by interchangeable lenses which modify the focal distance of the beam and the power density. Another common feature in all systems is a coaxial He-Ne pilot light which provides a red spot which unfortunately becomes invisible in a bleeding surgical field. Most surgical laser systems have a spacial mode of TEM 00 which is essential for incisional surgery. The continuous mode of beam delivery is used for incisional surgery and also for most endoscopic procedures.

  12. Spectral and Radiometric Calibration Using Tunable Lasers (United States)

    McCorkel, Joel (Inventor)


    A tunable laser system includes a tunable laser, an adjustable laser cavity for producing one or more modes of laser light emitted from the tunable laser, a first optical parametric oscillator positioned in a light path of the adjustable laser cavity, and a controller operable to simultaneously control parameters of at least the tunable laser, the first optical parametric oscillator, and the adjustable laser cavity to produce a range of wavelengths emitted from the tunable laser system. A method of operating a tunable laser system includes using a controller to simultaneously control parameters of a tunable laser, an adjustable laser cavity for producing one or more modes of laser light emitted from the tunable laser, and a first optical parametric oscillator positioned in a light path of the adjustable laser cavity, to produce a range of wavelengths emitted from the tunable laser system.

  13. Laser-based additive manufacturing of metals

    CSIR Research Space (South Africa)

    Kumar, S


    Full Text Available For making metallic products through Additive Manufacturing (AM) processes, laser-based systems play very significant roles. Laser-based processes such as Selective Laser Melting (SLM) and Laser Engineered Net Shaping (LENS) are dominating processes...

  14. A High Power Frequency Doubled Fiber Laser (United States)

    Thompson, Rob; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute


    This slide presentation reviews the power frequencies for the doubled fiber laser. It includes information on the 780 nm laser, second harmonic generation in one crystal, cascading crystals, the tenability of laser systems, laser cooling, and directions for future work.

  15. Laser scattering measurement for laser removal of graffiti (United States)

    Tearasongsawat, Watcharawee; Kittiboonanan, Phumipat; Luengviriya, Chaiya; Ratanavis, Amarin


    In this contribution, a technical development of the laser scattering measurement for laser removal of graffiti is reported. This study concentrates on the removal of graffiti from metal surfaces. Four colored graffiti paints were applied to stainless steel samples. Cleaning efficiency was evaluated by the laser scattering system. In this study, an angular laser removal of graffiti was attempted to examine the removal process under practical conditions. A Q-switched Nd:YAG laser operating at 1.06 microns with the repetition rate of 1 Hz was used to remove graffiti from stainless steel samples. The laser fluence was investigated from 0.1 J/cm2 to 7 J/cm2. The laser parameters to achieve the removal effectiveness were determined by using the laser scattering system. This study strongly leads to further development of the potential online surface inspection for the removal of graffiti.

  16. Ultrashort pulse laser technology laser sources and applications

    CERN Document Server

    Schrempel, Frank; Dausinger, Friedrich


    Ultrashort laser pulses with durations in the femtosecond range up to a few picoseconds provide a unique method for precise materials processing or medical applications. Paired with the recent developments in ultrashort pulse lasers, this technology is finding its way into various application fields. The book gives a comprehensive overview of the principles and applications of ultrashort pulse lasers, especially applied to medicine and production technology. Recent advances in laser technology are discussed in detail. This covers the development of reliable and cheap low power laser sources as well as high average power ultrashort pulse lasers for large scale manufacturing. The fundamentals of laser-matter-interaction as well as processing strategies and the required system technology are discussed for these laser sources with respect to precise materials processing. Finally, different applications within medicine, measurement technology or materials processing are highlighted.

  17. [The use of lasers in dermatology]. (United States)

    Lecocq, C; Pirard, D; del Marmol, V; Berlingin, E


    Albert Einstein is undoubtedly the father of lasers. But it is not until 1964 that the first dermatological lasers were introduced. The Nd-YAG laser, the CO2 laser were developed by Kumar Patel. In a 40 year period lasers not only were diversified but have also become safer and miniaturized. This article hopes to strengthen general practionners' and specialist's knowledge of the different categories of available lasers. The most frequently used ones are ablative lasers (CO2-Erbium), vascular lasers (Nd-YAG, KTP, pulsed dye laser) and the pigment lasers (Q-Switched Nd-YAG, Alexandrite). A description of these lasers and their indications in dermatology will be discussed.

  18. Laser Science and Applications (United States)

    El-Nadi, Lotfia M.; Mansour, Mohy S.


    Attosecond high harmonic pulses: generation and characterization / C. H. Nam and K. T. Kim -- High power lasers and interactions / C. Chatwin and R. Young -- Laser accelerators / L. M. El-Nadi ... [et al.] -- Energy levels, oscillator strengths, lifetimes, and gain distributions of S VII, CI VIII, and Ar IX / Wessameldin. S. Abdelaziz and Th. M. El-Sherbini -- The gain distribution according to theoretical level structure and decay dynamics of W[symbol] / H. M. Hamed ... [et al.] -- Raman spectroscopy and low temperature photoluminescence ZnSe[symbol]Te[symbol] ternary alloys / A. Salah ... [et al.] -- Automated polarization-discrimination technique to minimize lidar detected skylight background noise, part I / Y. Y. Hassebo, K. Elsayed and S. Ahmed -- Laser interferometric measurements of the physical properties for He, Ne gases and their mixture / N. M. Abdel-Moniem ... [et al.] -- Analytical studies of laser beam propagation through the atmosphere / M. I. El-Saftawy, A. M. Abd El-Hamed and N. Sh. Kalifa -- Laser techniques in conservation of artworks: problems and breakthroughs / R. Salimbeni and S. Siano -- Technology-aided heritage conservation laser cleaning for buildings / M. S. Nada -- Technology significance in conservation of the built heritage 3D visualization impact / M. S. Nada -- Simulation of optical resonators for Vertical-Cavity Surface-Emitting Lasers (VCSEL) / M. S. Mansour ... [et al.] -- Optical design alternatives: a survey study / A. A. K. Ismail, I. A. S. Ismail and S. H. Ahmed -- Materials for digital optical design; a survey study / A. A. K. Ismail, I. A. S. Ismail and S. H. Ahmed -- Proposed design for optical digital circuits / A. A. K. Ismail, I. A. S. Ismail and S. H. Ahmed -- Photo-induced effect on bacterial cells / M. H. El Batanouny ... [et al.] -- Laser and non-coherent light effect on peripheral blood normal and acute lymphoblastic leukemic cells by using different types of photosensitizers / M. H. El Batanouny ... [et al

  19. Laser treatment of enamel and dentine by different Er lasers (United States)

    Altshuler, Gregory B.; Belikov, Andrei V.; Erofeev, Andrew V.


    The results of primary comparative investigation of possible application of lasers based on four different Er-doped crystals (YAG, YLF, YSGG, YAP) are presented. The influence of laser wavelength and temporal structure of laser radiation on efficiency of hard tooth tissues treatment is considered. The experimental data on damage thresholds and efficiency of enamel and dentine removal under influence of submillisecond pulses of all four types of lasers are obtained.

  20. Laser And Nonlinear Optical Materials For Laser Remote Sensing (United States)

    Barnes, Norman P.


    NASA remote sensing missions involving laser systems and their economic impact are outlined. Potential remote sensing missions include: green house gasses, tropospheric winds, ozone, water vapor, and ice cap thickness. Systems to perform these measurements use lanthanide series lasers and nonlinear devices including second harmonic generators and parametric oscillators. Demands these missions place on the laser and nonlinear optical materials are discussed from a materials point of view. Methods of designing new laser and nonlinear optical materials to meet these demands are presented.

  1. Laser Photon Force Measurements using a CW Laser (United States)

    Gray, Perry; Edwards, David L.; Carruth, M. Ralph, Jr.; Munafo, Paul M. (Technical Monitor)


    The photon force resulting from the non-damaging impact of laser derived photons on a metallic target was measured using a vacuum compatible microbalance. This experiment quantitatively verified that the force resulting from laser photons impacting a reflective surface is measurable and predictable. The photon wavelength is 1064 mn and the laser is a multi-mode 30OW Nd YAG continuous wave (CW) laser.

  2. Laser tissue interactions: an update for otolaryngology (United States)

    Reinisch, Lou


    We review the laser, characteristics of laser light, the delivery of laser light, pulse lengths and laser tissue interactions. We review these parameters and how they have changed over the history of the laser and how we expect them to change in the future. This survey of laser use is targeted to the otolaryngologist. Very little background in lasers is necessary to follow the discussion. This is intended to introduce and reintroduce laser technology.

  3. Photonic Molecule Lasers Revisited (United States)

    Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J.


    Photonic molecules (PMs) formed by coupling two or more optical resonators are ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission. We will extend our recent study and present new results for a number of promising geometries. The authors acknowledge financial support from NSERC (Canada) and the CERC in Photonic Innovations of Y. Messaddeq.

  4. Apparatus for performing oil field laser operations (United States)

    Zediker, Mark S.; Land, Mark S.; Rinzler, Charles C.; Faircloth, Brian O.; Koblick, Yeshaya; Moxley, Joel F.


    A system, apparatus and methods for delivering high power laser energy to perform laser operations in oil fields and to form a borehole deep into the earth using laser energy. A laser downhole assembly for the delivery of high power laser energy to surfaces and areas in a borehole, which assembly may have laser optics and a fluid path.

  5. Excimer lasers for refractive surgery (United States)

    Vartapetov, Serge K.


    Over the last decade excimer lasers have been broadly used for technological and medical processes. One of the most widespread applications of excimer laser is the clinical use for refractive surgery. Refractive surgery with excimer lasers is the prevalent method for the eye acuity correction. Operation at 193 nanometers, the excimer laser is able to precisely sculpt the corneal surface to correct refractive errors. Both the increase in the accuracy of sculpturing and the predictability of procedures are the key elements of the excimer laser designed for refractive surgery. The novel excimer laser for refractive surgery is offered for small aberration treatment. The excimer laser with both a full aperture Gaussian beam and fly spot system is described. The comparison of different systems of laser correction is reviewed.

  6. Laser sources for object illumination

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, G.F. [Lawrence Livermore National Lab., CA (United States)


    The considerations which formulate the specifications for a laser illuminator are explained, using the example of an underwater object. Depending on the parameters which define the scenario, widely varying laser requirements result.

  7. Coupled optical resonance laser locking. (United States)

    Burd, S C; du Toit, P J W; Uys, H


    We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for locking the different lasers are obtained by modulating each laser at a different frequency and using lock-in detection of a single photodiode signal. Experimentally, we simultaneously lock a 369 nm and a 935 nm laser to the (2)S(1/2) → (2)(P(1/2) and (2)D(3/2) → (3)D([3/2]1/2) transitions, respectively, of Yb(+) ions generated in a hollow cathode discharge lamp. Stabilized lasers at these frequencies are required for cooling and trapping Yb(+) ions, used in quantum information and in high precision metrology experiments. This technique should be readily applicable to other ion and neutral atom systems requiring multiple stabilized lasers.

  8. Polymer laser bio-sensors

    DEFF Research Database (Denmark)

    Kristensen, Anders; Vannahme, Christoph; Hermannsson, Pétur Gordon


    Organic dye based distributed feed-back lasers, featuring narrow linewidth and thus high quality spectral resolution, are used as highly sensitive refractive index sensors. The design, fabrication and application of the laser intra-cavity sensors are discussed....

  9. NASA's laser-propulsion project (United States)

    Jones, L. W.; Keefer, D. R.


    Design concepts, study results, and research directions toward development of CW laser heating of remotely flying spacecraft fuels to provide high impulse thrust are presented. The incident laser radiation would be absorbed by hydrogen through a medium of a laser-supported plasma. The laser energy could be furnished from an orbiting solar-powered laser platform and used to drive the engines of an orbital transfer vehicle (OTV) at costs less than with a chemical propulsion system. The OTV propulsion chamber would be reduced in size comparable to the volume addition of the incident laser energy absorber. The temperatures in the hydrogen-fueled system could reach 5000-15,000 K, and studies have been done to examine the feasibility of ion-electron recombination. Kinetic performance, temperature field, and power necessary to sustain a laser thrust augmented system modeling results are discussed, along with near-term 30 kW CO2 laser system tests.

  10. Energy Conversion in Laser Propulsion

    National Research Council Canada - National Science Library

    Larson, C


    Analysis of energy conversion in laser propulsion is reported and compared to experimental studies of a laboratory scale propulsion device that absorbs laser energy and converts that energy to propellant kinetic energy...

  11. Femtosecond laser spectroscopy

    CERN Document Server

    Hannaford, Peter


    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...

  12. Fundamentals of semiconductor lasers

    CERN Document Server

    Numai, Takahiro


    This book explains physics under the operating principles of semiconductor lasers in detail based on the experience of the author, dealing with the first manufacturing of phase-shifted DFB-LDs and recent research on transverse modes.   The book also bridges a wide gap between journal papers and textbooks, requiring only an undergraduate-level knowledge of electromagnetism and quantum mechanics, and helps readers to understand journal papers where definitions of some technical terms vary, depending on the paper. Two definitions of the photon density in the rate equations and two definitions of the phase-shift in the phase-shifted DFB-LD are explained, and differences in the calculated results are indicated, depending on the definitions.    Readers can understand the physics of semiconductor lasers and analytical tools for Fabry-Perot LDs, DFB-LDs, and VCSELs and will be stimulated to develop semiconductor lasers themselves.

  13. Visible laser dazzle (United States)

    Eberle, B.; Forster, D.


    The presented work gives an overview on the efforts of the NATO SET-198 research task group. It comprises nonrestricted material, which is already published or is to be published in journals. Main topics are the development and validation of computer models in order to understand the impact of laser dazzling on the detection of objects in a scene but also on the accomplishment of visual-based tasks. The work includes laboratory and field dazzling tests on sensors and humans, computer eye-dazzle modeling, automatic character recognition and laboratory observer trials for validation purposes of the used algorithms. The impact of dazzling is studied in dependence of laser wavelength, laser power and camera type.

  14. Pulsed laser ablation of copper (United States)

    Jordan, R.; Cole, D.; Lunney, J. G.; Mackay, K.; Givord, D.


    The laser ablation of copper with a 532 nm, 6 ns laser has been investigated in the regime normally used for pulsed laser deposition. The ablation depth per pulse and the flux and energy distribution of the ions in the plume were measured and compared to the deposition rate as measured by a quartz microbalance. These measurements were compared with an analytic model of ablation via a laser sustained plasma. It is shown that self-sputtering of the growing film is significant.

  15. Laser vaccine adjuvants (United States)

    Kashiwagi, Satoshi; Brauns, Timothy; Gelfand, Jeffrey; Poznansky, Mark C


    Immunologic adjuvants are essential for current vaccines to maximize their efficacy. Unfortunately, few have been found to be sufficiently effective and safe for regulatory authorities to permit their use in vaccines for humans and none have been approved for use with intradermal vaccines. The development of new adjuvants with the potential to be both efficacious and safe constitutes a significant need in modern vaccine practice. The use of non-damaging laser light represents a markedly different approach to enhancing immune responses to a vaccine antigen, particularly with intradermal vaccination. This approach, which was initially explored in Russia and further developed in the US, appears to significantly improve responses to both prophylactic and therapeutic vaccines administered to the laser-exposed tissue, particularly the skin. Although different types of lasers have been used for this purpose and the precise molecular mechanism(s) of action remain unknown, several approaches appear to modulate dendritic cell trafficking and/or activation at the irradiation site via the release of specific signaling molecules from epithelial cells. The most recent study, performed by the authors of this review, utilized a continuous wave near-infrared laser that may open the path for the development of a safe, effective, low-cost, simple-to-use laser vaccine adjuvant that could be used in lieu of conventional adjuvants, particularly with intradermal vaccines. In this review, we summarize the initial Russian studies that have given rise to this approach and comment upon recent advances in the use of non-tissue damaging lasers as novel physical adjuvants for vaccines. PMID:25424797

  16. Laser ablation of concrete.

    Energy Technology Data Exchange (ETDEWEB)

    Savina, M.


    Laser ablation is effective both as an analytical tool and as a means of removing surface coatings. The elemental composition of surfaces can be determined by either mass spectrometry or atomic emission spectroscopy of the atomized effluent. Paint can be removed from aircraft without damage to the underlying aluminum substrate, and environmentally damaged buildings and sculptures can be restored by ablating away deposited grime. A recent application of laser ablation is the removal of radioactive contaminants from the surface and near-surface regions of concrete. We present the results of ablation tests on concrete samples using a high power pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied on various model systems consisting of Type I Portland cement with varying amounts of either fine silica or sand in an effort to understand the effect of substrate composition on ablation rates and mechanisms. A sample of non-contaminated concrete from a nuclear power plant was also studied. In addition, cement and concrete samples were doped with non-radioactive isotopes of elements representative of cooling waterspills, such as cesium and strontium, and analyzed by laser-resorption mass spectrometry to determine the contamination pathways. These samples were also ablated at high power to determine the efficiency with which surface contaminants are removed and captured. The results show that the neat cement matrix melts and vaporizes when little or no sand or aggregate is present. Surface flows of liquid material are readily apparent on the ablated surface and the captured aerosol takes the form of glassy beads up to a few tens of microns in diameter. The presence of sand and aggregate particles causes the material to disaggregate on ablation, with intact particles on the millimeter size scale leaving the surface. Laser resorption mass spectrometric analysis showed that cesium and potassium have similar chemical environments in the

  17. Lasers in clinical ophthalmology (United States)

    Ribeiro, Paulo A.


    The clinical application of lasers in ophthalmology is schematized, showing for each anatomic eye structure, pathologies that may be treated through this procedure. In the cornea, the unusual laser practice for suture removals and the promising possibility of the excimer laser in refractive surgery are discussed. In the iris, the camerular angle, and the ciliary body, the laser application is essentially used to treat the glaucoma and other situations that are not so frequent. The capsulotomy with YAG LASER is used in the treatment of structures related with crystalline and, at least, the treatment of the retina and choroid pathology is expanded. A. A. explained the primordial interest and important of laser in the diabetic retinopathy treatment and some results in patients with more than 5 years of evolution are: 55 of the patients with proliferative diabetic retinopathy (RDP) treated for more than 5 years noticed their vision improved or stabilized; 5 years after treating patients with PDR, 49.3 had their vision stabilized or even improved, provided the diabetics had declared itself more than 20 years ago, versus 61.7 provided the diabetics had declared itself less than 20 years before; finally, 53.8 of the patients under 40-years-old when the diabetics was diagnosed, had their vision improved or at least stabilized 5 years after the beginning of the treatment. On the other side, when patients were over 40 years old when the diabetics was diagnosed percentage increased to 55.9. This study was established in the follow-up of 149 cases over 10 years.


    African Journals Online (AJOL)

    9 mai 2013 ... laryngotrachéales, traités et suivis par Laser diode au service d'ORL et de chirurgie cervico-faciale de l'hôpital Habib. Thameur de Tunis. Résultats : L'âge moyen de nos patients était de 34 ans. Le sex-ratio était de 1,58. Les différentes pathologies laryngées traitées par Laser ont été classées de la façon ...

  19. Laser rangefinders - Recent developments (United States)

    Guyot, J.


    An evaluation is made of recent developments in the miniaturization and cost reduction of 1.06-micron laser rangefinders (LRFs) such as those employed in the control of firearms. LRFs can now be designed to furnish both target illumination and designation. In addition, the advantages of CO2 lasers operating in the 9-11 micron range have led to the design of devices capable of simultaneous target ranging and radial velocity measurements, coupling with FLIR imagers, frequency-hopping rangefinding, and the remote sensing of such battlefield gases as nerve agents.

  20. Lasers in oral implantology (United States)

    Arnabat-Domingeuz, Josep


    Nowadays the use of implants as a increasing therapy in dentistry and it has become a usual treatment in dental offices. More and more dentists have dental implants included in treatment plans for patients with missing teeth. Therefore is necessary that all dentists know all the possibilities of these treatments. Together with the emergence of dental implants, it is also beginning to see an increase in the onset of lasers in dentistry. These two new techniques in dentistry can be supplemented because as we will see the use of lasers in different cases can improve implant treatment.

  1. Study of Molecular Lasers (United States)


    in the relaxation of Br(2P1/2) by HC1 and HBr. However, these processes are not resonant. The spin-orbit splitting in Br(2J>1/2-> 8p3 /2=:3685 cm...1) or DF(/; = 1) by the parent molecule (Xa), [X] is the atom concentraiioa, TD is the laser induced fluores- cence decay time of HF(DF) in the...measurement of four quantities 0clz , T0, TD , [X]). The rate constant for relaxation by the parent mole- cule is found by a laser induced fluorescence

  2. Optics, light and lasers

    CERN Document Server

    Meschede, Dieter


    Starting from the concepts of classical optics, Optics, Light and Lasers introduces in detail the phenomena of linear and nonlinear light matter interaction, the properties of modern laser sources, and the concepts of quantum optics. Several examples taken from the scope of modern research are provided to emphasize the relevance of optics in current developments within science and technology. The text has been written for newcomers to the topic and benefits from the author's ability to explain difficult sequences and effects in a straightforward and easily comprehensible way. To this second, c

  3. Ultrafast laser patterning of graphene (United States)

    Bobrinetskiy, Ivan I.; Emelianov, Alexey V.; Lin, Chih-Lang; Otero, Nerea; Romero, Pablo M.


    This paper describes the recent results in ultrafast (femtoseconds and picoseconds) pulsed laser patterning of graphene films (single layer graphene, graphene oxide (GO)). We investigated such effects of nonlinear optical interaction like selective laser ablation of graphene, laser reduction of graphene oxide and local functionalization (oxidation) of graphene based on multiphoton absorption for microelectrode patterning. The graphene oxide and reduction was demonstrated under femtosecond laser pulses as well as fine ablation for monolayer GO films under ps laser pulses. We demonstrated the patterned laser reduction over the GO film leads to minimum in resistance for laser fluence because of interplay of chemical and thermal effects in carbon lattice and photons. The micro-scale patterns in graphene on SiO2 substrates were fabricated using ultrashort 515 nm laser pulses. For both picosecond and femtosecond laser pulses two competitive processes, based on photo-thermal (ablation) and photochemical (oxidation/etching) effects, were observed. The laser-induced etching of graphene starts just below the threshold energy of graphene ablation. The mechanisms of ultrafast laser interaction with graphene are discussed. Patterned graphene was investigated by AFM, microRaman, SEM and sheet resistance measurements and other techniques. The mechanisms of ultrafast laser interaction with graphene are discussed. The comprehensive models of graphene oxidation/reduction are suggested.

  4. Laser and nonlinear optical materials

    Energy Technology Data Exchange (ETDEWEB)

    De Shazer, L.G.


    This book contains 21 papers. Some of the titles are: Frequency conversion materials from a device perspective; Recent developments in area; Recent developments in barium borate; Growth of laser crystals at Airtron; Crystal growth and the future of solid state lasers; Faraday rotator materials for laser systems; and Mechanical properties of single crystal ceramics.

  5. Diode laser applications in urology (United States)

    Sam, Richard C.; Esch, Victor C.


    Diode lasers are air-cooled, efficient, compact devices which have the potential of very low cost when produced in quantity. The characteristics of diode lasers are discussed. Their applications in interstitial thermal treatment of the prostate, and laser ablation of prostate tissues, will be presented.

  6. Laser machining of advanced materials

    CERN Document Server

    Dahotre, Narendra B


    Advanced materialsIntroductionApplicationsStructural ceramicsBiomaterials CompositesIntermetallicsMachining of advanced materials IntroductionFabrication techniquesMechanical machiningChemical Machining (CM)Electrical machiningRadiation machining Hybrid machiningLaser machiningIntroductionAbsorption of laser energy and multiple reflectionsThermal effectsLaser machining of structural ceramicsIntrodu

  7. Tapered diode laser pumped 946 nm Nd:YAG laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Petersen, Paul Michael


    We successfully implemented a 946 nm Nd:YAG laser based on a 808 nm tapered diode pump laser. The tapered diode is developed at the Ferdinand-Braun-Institute fur Hochstfrequenztechnik in Germany. Figure 2 shows the experimental setup and results of each pump source coupled into a 1.5 mm crystal...... laser, we show that tapered diode laser pumping potentially increase the power of 946 nm lasers by a factor of two and reduce the threshold by a factor of three....

  8. Lasers in dental traumatology and low level laser therapy (LLLT). (United States)

    Caprioglio, C; Olivi, G; Genovese, M D


    Dental trauma in children is a frequent and often complex clinical event in which laser-assisted therapy, particularly using erbium lasers, can offer new treatment possibilities, improving the outcomes and reducing the associated complications. In particular, it is worth considering that the use of laser-assisted therapies is associated with a marked reduction in the use of analgesics and anti-inflammatory medications compared with conventional procedures. Laser anaesthesia is another interesting and challenging area. Given the paucity of data on laser-assisted dental trauma therapy in the international literature and the absence of well-structured guidelines, this is an area ripe for scientific research.

  9. Ho:YLF Laser Pumped by TM:Fiber Laser

    Directory of Open Access Journals (Sweden)

    Mizutani Kohei


    Full Text Available A 2-micron Ho:YLF laser end-pumped by 1.94-micron Tm:fiber laser is described. A ring resonator of 3m length is adopted for the oscillator. The laser is a master oscillator and an amplifier system. It is operated at high repetition rate of 200-5000 Hz in room temperature. The laser outputs were about 9W in CW and more than 6W in Q-switched operation. This laser was developed to be used for wind and CO2 measurements.

  10. Nonlinear laser energy depletion in laser-plasma accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Shadwick, B.A.; Schroeder, C.B.; Esarey, E.


    Energy depletion of intense, short-pulse lasers via excitation of plasma waves is investigated numerically and analytically. The evolution of a resonant laser pulse proceeds in two phases. In the first phase, the pulse steepens, compresses, and frequency red-shifts as energy is deposited in the plasma. The second phase of evolution occurs after the pulse reaches a minimum length at which point the pulse rapidly lengthens, losing resonance with the plasma. Expressions for the rate of laser energy loss and rate of laser red-shifting are derived and are found to be in excellent agreement with the direct numerical solution of the laser field evolution coupled to the plasma response. Both processes are shown to have the same characteristic length-scale. In the high intensity limit, for nearly-resonant Gaussian laser pulses, this scale length is shown to be independent of laser intensity.

  11. Laser Prostatectomy: Holmium Laser Enucleation and Photoselective Laser Vaporization of the Prostate (United States)

    Bostanci, Yakup; Kazzazi, Amir; Djavan, Bob


    Historically, transurethral resection of the prostate has been the gold standard for the treatment of benign prostatic hyperplasia (BPH). Laser technology has been used to treat BPH for > 15 years. Over the past decade, it has gained wide acceptance by experienced urologists. This review provides an evidence-based update on laser surgery for BPH with a focus on photoselective laser vaporization and holmium laser enucleation of the prostate surgeries and assesses the safety, efficacy, and durability of these techniques. PMID:23671400

  12. Macular Burns from Nonmedical Lasers. (United States)

    Sayman Muslubaş, Işıl; Hocaoğlu, Mümin; Arf, Serra; Özdemir, Hakan; Karaçorlu, Murat


    Laser devices are widely used for medical, military, industrial and entertainment purposes. This extensive and unregulated use of lasers can cause a variety of maculopathies that can result in permanent vision loss. Uncontrolled and inappropriate use of laser instruments should be prevented with strict rules. We strongly emphasize the importance of changing the general misperception that lasers are safe to use for entertainment purposes. In this study we aim to report the clinical features of three patients with a history of maculopathy caused by exposure to laser light in an entertainment venue.

  13. Macular Burns from Nonmedical Lasers

    Directory of Open Access Journals (Sweden)

    Işıl Sayman Muslubaş


    Full Text Available Laser devices are widely used for medical, military, industrial and entertainment purposes. This extensive and unregulated use of lasers can cause a variety of maculopathies that can result in permanent vision loss. Uncontrolled and inappropriate use of laser instruments should be prevented with strict rules. We strongly emphasize the importance of changing the general misperception that lasers are safe to use for entertainment purposes. In this study we aim to report the clinical features of three patients with a history of maculopathy caused by exposure to laser light in an entertainment venue.

  14. Gasdynamic lasers and photon machines. (United States)

    Christiansen, W. H.; Hertzberg, A.


    The basic operational highlights of CO2-N2 gasdynamic lasers (GDL's) are described. Features common to powerful gas lasers are indicated. A simplified model of the vibrational kinetics of the system is presented, and the importance of rapid expansion nozzles is shown from analytic solutions of the equations. A high-power pulsed GDL is described, along with estimations of power extraction. A closed-cycle laser is suggested, leading to a description of a photon generator/engine. Thermodynamic analysis of the closed-cycle laser illustrates in principle the possibility of direct conversion of laser energy to work.

  15. Laser conservation of art. (United States)

    Nevin, Austin; Pouli, Paraskevi; Georgiou, Savas; Fotakis, Costas


    Focusing a laser on the dirt covering a precious work of art may seem like a dangerous thing to do, but this unexpected technique has found a variety of cleaning applications. Analogies from other fields of materials science can provide guidance for its use, and model experiments ensure it doesn't all end in disaster.

  16. Coherent laser vision system

    Energy Technology Data Exchange (ETDEWEB)

    Sebastion, R.L. [Coleman Research Corp., Springfield, VA (United States)


    The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  17. Research on Molecular Lasers (United States)


    subcontractor, grantee. Department of De- fense aciivlty or other organization (corporate author) issuing the report. 2a. REPORT SECUHTY...Atoms," Paper MD8- 4th Conference en Chemica ] and Molecular Lasers., St. Louis, Mo. October 21-23, 1974. 3. M.I. Buchwald and G.J. Wolga

  18. Free-electron lasers

    CERN Document Server

    Schmüser, P


    The synchrotron radiation of relativistic electrons in undulator magnets and the low-gain Free-Electron Laser (FEL) are discussed in some detail. The highgain FEL based on the principle of Self Amplified Spontaneous Emission is treated on a qualitative level.

  19. Sintering in Laser Sintering (United States)

    Bourell, David L.


    Laser sintering is a popular additive manufacturing technology, particularly for service parts. Invented by C. Deckard in the mid-1980s, the approach of using a laser to densify a powder bed selectively has been extensively researched and has been applied to metals, ceramics, polymers and composites. In the traditional powder-metallurgical sense, sintering involves solid-state atomic transport resulting in neck formation and eventual densification in a powder mass. The use of the term "sintering" as a descriptive term for the powder-bed additive manufacturing process has been problematical to the technical community, because the predominant densification mechanism has been shown for most applications to be melting and reflow. The term has perpetuated as a name for the additive manufacturing process, at least for polymers. The technical term "sintering" is accurately associated with laser sintering insofar as powder pre-processing and part post-processing are concerned. It may also be used to describe formation of "part cake". This paper describes the circumstances surrounding the coining of the term, "laser sintering" and provides some examples of how sintering is used in pre- and post-processing.

  20. Dielectric Waveguide lasers

    NARCIS (Netherlands)

    Pollnau, Markus; Orlovic, V.A.; Pachenko, V.; Scherbakov, I.A.


    Our recent results on planar and channel waveguide fabrication and lasers in the dielectric oxide materials Ti:sapphire and rare-earth-ion-doped potassium yttrium double tungstate (KYW) are reviewed. We have employed waveguide fabrication methods such as liquid phase epitaxy and reactive ion etching

  1. Laser sensor system documentation. (United States)


    Phase 1 of TxDOT Project 0-6873, True Road Surface Deflection Measuring Device, developed a : laser sensor system based on several sensors mounted on a rigid beam. : This sensor system remains with CTR currently, as the project is moving into Phase 2...

  2. Scanning laser Doppler vibrometry

    DEFF Research Database (Denmark)

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  3. YAG laser in ophthalmology (United States)

    Jelinkova, Helena; Pasta, Jiri; Sulc, Jan; Nemec, Michal; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji


    A summary of using near (Nd) and middle (Er) infrared YAG laser systems in ophthalmology surgery is given in the paper. The report on twelve years of clinical experience with the ophthalmic Nd:YAG laser system (λ=1.06 μm) operating alternatively on Q-switched or mode-locked regimes is accomplished. From statistical data processing of more than 1000 interventions it follows that better results in a posterior capsule opacification cure are achieved with the use of short, near-infrared mode-locked 25 ps long pulses, while 4 ns long giant pulses of the same wavelength are useful for iridectomy creations. Middle infrared radiation generated by the Er:YAG laser system (λ-2.94 μm) was used for pre-clinical interaction experiments (in vitro). Differences in results of cornea, lens and sclera ablation by a free running (110 μs long) and Q-switched (250 ns long) mid-infrared pulses are presented. The radiation was delivered to the interaction place either by a system of reflected mirrors (used for Nd:YAG laser), or by a special sealed waveguide (in the case of Er:YAG system).

  4. YAG Laser or bur

    African Journals Online (AJOL)


    5 days ago ... (erbium, chromium: yttrium aluminum garnet) laser and two different adhesive systems. Materials and Methods. Sample Preparation and Study Groups. A total of 25 freshly extracted restoration- and caries- free primary molar teeth were selected randomly for the study. The teeth were cleaned of calculus, ...

  5. Oxazine laser dyes (United States)

    Hammond, Peter R.; Field, George F.


    New oxazine compounds useful as dye laser media in solution, are superiior to prior art materials. The oxazine dyes useful when pumped by the 578.2 nm copper line to operate in the 700-800 nm range are described by formula I ##STR1##

  6. Laser Cutting, Development Trends

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove


    In this paper a short review of the development trends in laser cutting will be given.The technology, which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal, as it will expand in heavy industry and in cutting...

  7. Laser Soap Fountain (United States)

    Foley, Tyler; Pegram, Matthew; Jenkins, Zachary; Hester, Brooke C.; Burris, Jennifer L.


    We have developed an eye-catching demonstration that showcases a variety of physics topics from total internal reflection to electrostatics to non-Newtonian fluid dynamics, including the Kaye effect. The essential components of the demonstration include a vertical stream of liquid soap in which a laser pointer is internally reflected, and which…

  8. Research in Laser Processes (United States)


    THEORY OF/^W PRESSURE DEPENDENCE General model The total density of excited-state species fNaf ] as- sociated with the Na’OP) configuration...critical laser power. In addition to raising the discharge impedance, this lower nr condition would prob- ably yield higher efficiency in a real case

  9. Laser enhanced chemical reactions (United States)

    Included is the discussion of infrared diode lasers used to study time dependent dynamic events. Also, hot atom excitation of vibrational states of polyatomic molecules, bimolecular quenching and reactions of O(sup 1)D, bimolecular reaction studies of the OH + CO yields H + CO2 system, and the chemical dynamics of the reaction between chlorine atoms and deuterated cyclohexane are covered briefly.

  10. Laser machining wood composites (United States)

    Vladimir Barnekov; Henry A. Huber; Charles W. McMillin


    This practical, nonstatistical experiment using commercial equipment demonstrated that nominal 3/4-inch compositep anelsf or furniture consisting of a particleboard core,h igh density melamine crossbands, and walnut veneer face plies can be cut with a carbon dioxide/airjet-assisted laser to produce surfaces with minimal nonparallelism and char compared to previous...

  11. Laser Assisted Microsurgical Anastomosis. (United States)


    our axoral transport platophysiological and ultravascular findings indicat to be inferior ll. to laser epineurial repair, conventional microsurgical...ventral motoneurons . Experimental Neurology, 21:41-51, 1968. 21. Marinacci, AA: Diagnosis of "all median hand". 22. Marinacci, AA: The problem of unusual

  12. Laser Welding in Space (United States)

    Workman, Gary L.; Kaukler, William F.


    Solidification type welding process experiments in conditions of microgravity were performed. The role of convection in such phenomena was examined and convective effects in the small volumes obtained in the laser weld zone were observed. Heat transfer within the weld was affected by acceleration level as indicated by the resulting microstructure changes in low gravity. All experiments were performed such that both high and low gravity welds occurred along the same weld beam, allowing the effects of gravity alone to be examined. Results indicate that laser welding in a space environment is feasible and can be safely performed IVA or EVA. Development of the hardware to perform the experiment in a Hitchhiker-g platform is recomended as the next step. This experiment provides NASA with a capable technology for welding needs in space. The resources required to perform this experiment aboard a Shuttle Hitchhiker-pallet are assessed. Over the four year period 1991 to 1994, it is recommended that the task will require 13.6 manyears and $914,900. In addition to demonstrating the technology and ferreting out the problems encountered, it is suggested that NASA will also have a useful laser materials processing facility for working with both the scientific and the engineering aspects of materials processing in space. Several concepts are also included for long-term optimization of available solar power through solar pumping solid state lasers directly for welding power.

  13. Advanced Laser Source Research. (United States)


    E E -L- CTE JUL 10 01987COTET ;Z, Nonlinear Spectroscopy: Arthur L. Schawlow, Principal Investigator (2) Tunable Lasers and Coherent Light Techniques...spin), i.e., they will tend to rotate clockwise versus counterclockwise. When a football is thrown at high speed and lands on a grass field, it almost

  14. Laser Lightcraft Performance (United States)

    Chen, Yen-Sen; Liu, Jiwen; Wei, Hong


    The purpose of this study is to establish the technical ground for modeling the physics of laser powered pulse detonation phenomenon. The principle of the laser power propulsion is that when high-powered laser is focused at a small area near the surface of a thruster, the intense energy causes the electrical breakdown of the working fluid (e.g. air) and forming high speed plasma (known as the inverse Bremsstrahlung, IB, effect). The intense heat and high pressure created in the plasma consequently causes the surrounding to heat up and expand until the thrust producing shock waves are formed. This complex process of gas ionization, increase in radiation absorption and the forming of plasma and shock waves will be investigated in the development of the present numerical model. In the first phase of this study, laser light focusing, radiation absorption and shock wave propagation over the entire pulsed cycle are modeled. The model geometry and test conditions of known benchmark experiments such as those in Myrabo's experiment will be employed in the numerical model validation simulations. The calculated performance data will be compared to the test data.

  15. Laser Beam Scanning Device. (United States)

    metal mirror. Multiple thermocouple wires attached to the rear of the mirror provide temperature (and hence beam power) information at various points...on the mirror. Scanning is achieved by means of a selector switch which sequentially samples the thermocouple outputs. The thermocouple output voltages are measured and recorded as a function of laser beam power.

  16. Subwavelength micropillar array terahertz lasers. (United States)

    Krall, Michael; Brandstetter, Martin; Deutsch, Christoph; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried; Unterrainer, Karl


    We report on micropillar-based terahertz lasers with active pillars that are much smaller than the emission wavelength. These micropillar array lasers correspond to scaled-down band-edge photonic crystal lasers forming an active photonic metamaterial. In contrast to photonic crystal lasers which use significantly larger pillar structures, lasing emission is not observed close to high-symmetry points in the photonic band diagram, but in the effective medium regime. We measure stimulated emission at 4 THz for micropillar array lasers with pillar diameters of 5 µm. Our results not only demonstrate the integration of active subwavelength optics in a terahertz laser, but are also an important step towards the realization of nanowire-based terahertz lasers.

  17. 2 micron femtosecond fiber laser (United States)

    Liu, Jian; Wan, Peng; Yang, Lihmei


    Methods and systems for generating femtosecond fiber laser pulses are disclose, including generating a signal laser pulse from a seed laser oscillator; using a first amplifier stage comprising an input and an output, wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits an amplified and stretched signal laser pulse; using an amplifier chain comprising an input and an output, wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits a further amplified, stretched signal laser pulse. Other embodiments are described and claimed.

  18. Solid-State Random Lasers

    CERN Document Server

    Noginov, Mikhail A


    Random lasers are the simplest sources of stimulated emission without cavity, with the feedback provided by scattering in a gain medium. First proposed in the late 60’s, random lasers have grown to a large research field. This book reviews the history and the state of the art of random lasers, provides an outline of the basic models describing their behavior, and describes the recent advances in the field. The major focus of the book is on solid-state random lasers. However, it also briefly describes random lasers based on liquid dyes with scatterers. The chapters of the book are almost independent of each other. So, the scientists or engineers interested in any particular aspect of random lasers can read directly the relevant section. Researchers entering the field of random lasers will find in the book an overview of the field of study. Scientists working in the field can use the book as a reference source.

  19. Low quantum defect laser performance (United States)

    Bowman, Steven R.


    Low quantum defect lasers are possible using near-resonant optical pumping. This paper examines the laser material performance as the quantum defect of the laser is reduced. A steady-state model is developed, which incorporates the relevant physical processes in these materials and predicts extraction efficiency and waste heat generation. As the laser quantum defect is reduced below a few percent, the impact of fluorescence cooling must be included in the analysis. The special case of a net zero quantum defect laser is examined in detail. This condition, referred to as the radiation balance laser (RBL), is shown to provide two orders of magnitude lower heat generation at the cost of roughly 10% loss in extraction efficiency. Numerical examples are presented with the host materials Yb:YAG and Yb:Silica. The general conditions, which yield optimal laser efficiency, are derived and explored.

  20. Laser system with wavelength converter

    DEFF Research Database (Denmark)


    The present invention relates to an apparatus comprising a diode laser (10) providing radiation in a first wavelength interval, a radiation conversion unit (12) having an input and an output, the radiation converter configured to receive the radiation in the first wavelength interval from the diode...... laser at the input, the radiation conversion unit configured to convert the radiation in the first wavelength interval to radiation in a second wavelength interval and the output configured to output the converted radiation, the second wavelength interval having one end point outside the first...... wavelength interval. Further, the invention relates to a method of optically pumping a target laser (14) in a laser system, the laser system comprising a laser source providing radiation at a first frequency, the laser source being optically connected to an input of a frequency converter, the frequency...

  1. Study of vibrations and stabilization of linear collider final doublets at the sub-nanometer scale; Etude des vibrations et de la stabilisation a l'echelle sous-nanometrique des doublets finaux d'un collisionneur lineaire

    Energy Technology Data Exchange (ETDEWEB)

    Bolzon, B


    CLIC is one of the current projects of high energy linear colliders. Vertical beam sizes of 0.7 nm at the time of the collision and fast ground motion of a few nanometers impose an active stabilization of the final doublets at a fifth of nanometer above 4 Hz. The majority of my work concerned vibrations and active stabilization study of cantilever and slim beams in order to be representative of the final doublets of CLIC. In a first part, measured performances of different types of vibration sensors associated to an appropriate instrumentation showed that accurate measurements of ground motion are possible from 0.1 Hz up to 2000 Hz on a quiet site. Also, electrochemical sensors answering a priori the specifications of CLIC can be incorporated in the active stabilization at a fifth of nanometer. In a second part, an experimental and numerical study of beam vibrations enabled to validate the efficiency of the numerical prediction incorporated then in the simulation of the active stabilization. Also, a study of the impact of ground motion and of acoustic noise on beam vibrations showed that an active stabilization is necessary at least up to 1000 Hz. In a third part, results on the active stabilization of a beam at its two first resonances are shown down to amplitudes of a tenth of nanometer above 4 Hz by using in parallel a commercial system performing passive and active stabilization of the clamping. The last part is related to a study of a support for the final doublets of a linear collider prototype in phase of finalization, the ATF2 prototype. This work showed that relative motion between this support and the ground is below imposed tolerances (6 nm above 0.1 Hz) with appropriate boundary conditions. (author)

  2. Laser modulator for LISA pathfinder (United States)

    Voland, C.; Lund, G.; Coppoolse, W.; Crosby, P.; Stadler, M.; Kudielka, K.; Özkan, C.


    LISA Pathfinder is an ESA experiment to demonstrate the key technologies needed for the LISA mission to detect gravitational waves in space. The LISA Pathfinder spacecraft represents one arm of the LISA interferometer, containing an optical metrology system and two proof masses as inertial references for the drag-free control system. The LISA Pathfinder payload consists of two drag-free floating test masses located in the inertial sensors with their control electronics and an optical metrology subsystem. The optical metrology subsystem monitors the movement of both test masses relative to each other and to the spacecraft with very high sensitivity and resolution. This is achieved with a heterodyne Mach- Zehnder interferometer. This interferometer requires as input two coherent laser beams with a heterodyne frequency difference of a few kHz. To generate the two laser beams with a heterodyne frequency difference a Nd:YAG laser is used together with the Laser Modulator. The Nd:YAG laser generates a single coherent laser signal at a wavelength of 1064nm which is fibre coupled to the Laser Modulator. The Laser Modulator then generates the two optical beams with the required heterodyne frequency offset. In addition, the Laser Modulator is required to perform laser amplitude stabilization and optical path difference control for the two optical signals. The Laser Modulator consists of an optical unit - the LMU - and RF synthesiser, power amplification and control electronics. These electronics are all housed in the Laser Modulator Electronics (LME). The LMU has four primary functions: • Splitting of the input laser beam into two paths for later superposition in the interferometer. • Applying different frequency shifts to each of the beams. • Providing amplitude modulation control to each of the beams. • Providing active control of the optical path length difference between the two optical paths. The present paper describes the design and performance of the LMU

  3. Electrodeless excimer laser; Laser a eccimeri senza elettrodi

    Energy Technology Data Exchange (ETDEWEB)

    Lisi, N. [ENEA, Divisione Nuovi Materiali, Centro Ricerche Casaccia, Rome (Italy)


    In this paper it is proposed how to build an excimer laser based on an electrodeless discharge (or Dielectric Barrier Discharge). Such laser could operate with a low energy per pulse (<100 mJ) and a high repetition rate (<100 kHz). The most relevant advantage an electrodeless DBD laser is the much longer gas mixture lifetime. This feature could allow the operation of a sealed laser emitting higher average power with respect to commercially available excimer lasers. Such discharge scheme could be advantageous in order to excite the F{sub 2} excimer molecule, whose emission wavelength in the VUV range (157 nm) at high reprate is particularly interesting in the micro-lithography field. [Italian] In questo documento viene proposto come costruire un laser a eccimeri basato su una scarica priva di elettrodi, o Dielectric Barrier Discharge. Tale laser puo' funzionare con una bassa energia per impulso (<100 mJ) ad alta frequenza di ripetizione (<100 kHz). Il vantaggio fondamentale di un laser a DBD e quindi privo di elettrodi e' la vita media della miscela gassosa molto piu' alta che potrebbe permettere alla camera laser di operare sigillata ad una potenza media superiore a quella dei laser a eccimeri attuali. Tale schema di pompaggio potrebbe essere particolarmente vantaggioso per eccitare la molecola eccimero F{sub 2} la cui lunghezza di emissione nel VUV (157 nm) ad elevata frequenza di ripetizione presenta un notevole interesse nel campo della produzione di microcircuiti.

  4. Chaotic He-Ne laser (United States)

    Kuusela, Tom A.


    A He-Ne laser is an example of a class A laser, which can be described by a single nonlinear differential equation of the complex electric field. This laser system has only one degree of freedom and is thus inherently stable. A He-Ne laser can be driven to the chaotic condition when a large fraction of the output beam is injected back to the laser. In practice, this can be done simply by adding an external mirror. In this situation, the laser system has infinite degrees of freedom and therefore it can have a chaotic attractor. We show the fundamental laser equations and perform elementary stability analysis. In experiments, the laser intensity variations are measured by a simple photodiode circuit. The laser output intensity time series is studied using nonlinear analysis tools which can be found freely on the internet. The results show that the laser system with feedback has an attractor of a reasonably high dimension and that the maximal Lyapunov exponent is positive, which is clear evidence of chaotic behaviour. The experimental setup and analysis steps are so simple that the studies can even be implemented in the undergraduate physics laboratory.

  5. Laser beam removal of microstructures with Nd:YAG lasers (United States)

    Hellrung, Dirk; Gillner, Arnold; Poprawe, Reinhart


    Laser beam removal with Nd:YAG-lasers is a manufacturing method to produce micro-structures with the precision of a few micrometers. Because many materials can be structured with laser radiation, especially hard metals and ceramics, it is a very flexible technology for the production of tools for micro-embossing and micro-stamping. The combination of the laser and stamping technology offers the possibility to produce high quantities of micro-parts at moderate costs. A system for laser beam removal, existing of a handling with a CAD/CAM coupling and a diode pumped solid state laser was developed and in several investigations the quality of these micro-tools was tested.

  6. Laser-Plasma Acceleration with FLAME and ILIL Ultraintense Lasers

    Directory of Open Access Journals (Sweden)

    Naveen Pathak


    Full Text Available We report on the development of radiation and electron sources based on laser-plasma acceleration for biomedical and nuclear applications, using both the table top TW laser at ILIL and the 220 TW FLAME laser system at LNF. We use the ILIL laser to produce wakefield electrons in a self-focusing dominated regime in a mm scale gas-jet to generate large, uniform beams of MeV electrons for electron radiography and radiobiology applications. This acceleration regime is described in detail and key parameters are given to establish reproducible and reliable operation of this source. We use the FLAME laser to drive laser-plasma acceleration in a cm-scale gas target to obtain stable production of >100 MeV range electrons to drive a Thomson scattering ɣ-ray source for nuclear applications.

  7. Paediatric laser dentistry. Part 2: Hard tissue laser applications. (United States)

    Olivi, G; Caprioglio, C; Olivi, M; Genovese, M D


    Erbium lasers can provide effective and minimally invasive caries removal in children. The bonding phase remains a critic step as well as the choice of material. Glass ionomers exhibits lower bonding properties in laser irradiated teeth compared to the conventional method or to composite and resin modified glass ionomer. Laser can also provide effective decontamination and coagulation effects in vital and non vital pulp therapy of primary teeth, improving and simplifying the cleaning and disinfecting steps.

  8. Ultrafast lasers in ophthalmology (United States)

    Lubatschowski, Holger

    Ultrafast laser pulses have become a promising tool for microsurgery of the eye. Due to the low energy threshold, side effects are limited to the micrometer range This precision enables the use of ultrashort laser pulses in a broad field of medical applications. Especially, the interaction process based on nonlinear absorption offers the opportunity to process transparent tissue not only on top of a surface but three dimensionally inside the bulk. This mechanism is used in refractive eye surgery, where fs pulses create flaps into the corneal tissue to remodel the curvature of the eye and to improve visual acuity. Moreover, fs pulses could be used to influence the biomechanics of the crystalline lens of the eye and improve accommodation on eyes who suffer from presbyopia.

  9. Remote ultrasensitive laser microphone (United States)

    Sánchez Guerrero, G.; Guajardo Gonzáles, C.; Viera González, P.; Selvas, R.; Ramos Traslosheros, L.


    This paper presents an optical fiber Mach-Zehnder interferometer configured as an ultra-sensitive sound detector. We used a 633nm, 0.5 mW, He-Ne laser, two 3dB couplers, a few meter of telecomm fiber, an U-bench mount to increase the sensitivity of the device and an acquisition system composed by a photodiode and an amplifier connected to a laptop and to an oscilloscope. The optoelectronic device enables us to record acoustic signals from sources at distances longer than 4 meters, converting the interference patterns induced by the sound waves into a digital signal. The ease of its applicability, thanks to its small size and low weight, and its ultra-sensitivity makes this laser microphone a very attractive solution to issues such as monitoring, no-detectable sensing and perimeter protection.

  10. Dental Lasers and Application Fields in Endodontics


    Emrah Çetin; Hicran Dönmez Özkan; Senem Gökçen Yiğit Özer


    Since the first laser application in endodontics by Weichman in 1971, search for new laser devices is being proposed with the rapid development of laser technology. The purpose of this article is to update the information on laser application fields in endodontics and give information regarding the advantages and limitations of the laser devices.

  11. Dental Lasers and Application Fields in Endodontics

    Directory of Open Access Journals (Sweden)

    Emrah Çetin


    Full Text Available Since the first laser application in endodontics by Weichman in 1971, search for new laser devices is being proposed with the rapid development of laser technology. The purpose of this article is to update the information on laser application fields in endodontics and give information regarding the advantages and limitations of the laser devices.

  12. Electric motor for laser-mechanical drilling (United States)

    Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.


    A high power laser drilling system utilizing an electric motor laser bottom hole assembly. A high power laser beam travels within the electric motor for performing a laser operation. A system includes a down hole electrical motor having a hollow rotor for conveying a high power laser beam having a wavelength less than 1060 nm through the electrical motor.

  13. Laser Doppler anemometry (United States)

    Johnson, Dennis A.


    The material in this NASA TM is to appear as a chapter on Laser Doppler Anemometry (LDA) in the AGARDograph entitled, A Survey of Measurements and Measuring Techniques in Rapidly Distorted Compressible Turbulent Boundary Layers. The application of LDA (specifically, the dual-beam, burst-counter approach) to compressible flows is discussed. Subjects treated include signal processing, particle light scattering and tracking, data reduction and sampling bias, and three-dimensional measurements.

  14. Microdentistry with Lasers (United States)

    Prathima, G S; Bhadrashetty, Dinesh; Babu, S B Umesh; Disha, P


    Treating infants and young children is a rewarding experience, especially when we guide parents and children down the path of prevention and interception of oral disease. The pediatric dentist has to be updated about the new technologies to treating patients along with basic principles. This article gives a brief discussion on the types, applications, advantages, and limitations of the use of lasers in pediatric dentistry. PMID:26435633

  15. Laser removal of tattoos. (United States)

    Tammaro, A; Fatuzzo, G; Narcisi, A; Abruzzese, C; Caperchi, C; Gamba, A; Parisella, F R; Persechino, S


    In Western countries the phenomenon of "tattooing" is expanding and tattoos are considered a new fashion among young people. In this paper we briefly trace the history of tattooing, the techniques used, the analysis of pigments used, and their possible adverse reactions. We also carried out a review of the international literature on the use of Q-switched laser in tattoo removal and its complications, and we describe our experience in the use of this technique.

  16. Laser Pump Lamp (United States)


    1080, Project 202801 for the Air Force Avionics Laboratory, 405B Group, Wright Patterson AFB, Ohio. The Air Force technical monitor was Mr. james...Heitman (AFAL/ 405B ). The program was carried out from December 1974 to October 1975 in the Engineering Division of ILC Technology, Inc., Sunnyvale, Calif...Development Program (ADP/ 405B ). The overall goal of the Air Force effort is to es- tablish a high data rate intersatelJite laser communications .ystem

  17. Laser Gyro Theory Extension. (United States)


    PROPOSED OPTICAL TEST OF PREFERRED FRAME COSMOLOGIES .. ........... ............... 37 co(jes~ ’vl. fiii I. INTRODUCTION Research on "Laser Gyro Theory... gravitation . It is clear from our analysis that an earthbound experiment to observe the yet-unobserved geodetic procession and Lense-Thirring effect is...Quantum Electron. QE-16(9):918-935, 1980. M. P. Haugan, M. 0. Scully, and K. Just, "A proposed optical test of preferred frame cosmologies ," Phys. Lett. 77A

  18. Development of laser materials processing and laser metrology techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Chung, Chin Man; Kim, Jeong Mook; Kim, Min Suk; Kim, Kwang Suk; Baik, Sung Hoon; Kim, Seong Ouk; Park, Seung Kyu


    The applications of remote laser materials processing and metrology have been investigated in nuclear industry from the beginning of laser invention because they can reduce the risks of workers in the hostile environment by remote operation. The objective of this project is the development of laser material processing and metrology techniques for repairing and inspection to improve the safety of nuclear power plants. As to repairing, we developed our own laser sleeve welding head and innovative optical laser weld monitoring techniques to control the sleeve welding process. Furthermore, we designedand fabricated a 800 W Nd:YAG and a 150 W Excimer laser systems for high power laser materials processing in nuclear industry such as cladding and decontamination. As to inspection, we developed an ESPI and a laser triangulation 3-D profile measurement system for defect detection which can complement ECT and UT inspections. We also developed a scanning laser vibrometer for remote vibration measurement of large structures and tested its performance. (author). 58 refs., 16 tabs., 137 figs.

  19. [Lasers in dentistry 4. Removal of carious tissue using lasers]. (United States)

    Reich, E


    Many lasers are available today for clinical application in dentistry. For the removal of caries in enamel or dentin only few lasers can be used. Er:YAG lasers have a wavelength that coincides with the absorption maximum of water. Because of this characteristic the ablative effect in enamel and dentin is high and these lasers can be used beneficially for caries removal and small preparations. The possible side effects of Er:YAG lasers with water-cooling are minor compared to those of rotary instruments. A pulpal reaction will occur only if there is a very thin dentin layer over the pulp or direct application of the laser beam to the pulp. There is no increased heating with the Er:YAG laser so with vital teeth there is a positive reaction by the formation of reparative dentin. To the existing indications for lasers like caries removal and preparation of small cavities, in the future new techniques can be added like the use of dyes for enhancement of absorption of the laser radiation, and minimal invasive techniques using feedback from a system for caries detection.

  20. Analysis of multipass laser amplifier systems for storage laser media

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, J.F.


    The performance characteristics of single pass and multipass storage laser amplifiers are presented and compared. The effects of the multipass amplifier parameters on the extraction characteristics are examined. For a wide range of conditions the multipass amplifier is found to provide high energy gain and high efficiency simultaneously. This is a significant advantage over the single pass laser amplifier. Finally, three specific storage laser amplifier systems, flashlamp pumped V:MgF/sub 2/, XeF laser pumped Tm:Glass, and photolytically pumped Selenium, are examined. The performance characteristics for each of the three systems are calculated and compared.

  1. Safe laser application requires more than laser safety (United States)

    Frevel, A.; Steffensen, B.; Vassie, L.


    An overview is presented concerning aspects of laser safety in European industrial laser use. Surveys indicate that there is a large variation in the safety strategies amongst industrial laser users. Some key problem areas are highlighted. Emission of hazardous substances is a major problem for users of laser material processing systems where the majority of the particulate is of a sub-micrometre size, presenting a respiratory hazard. Studies show that in many cases emissions are not frequently monitored in factories and uncertainty exists over the hazards. Operators of laser machines do not receive adequate job training or safety training. The problem is compounded by a plethora of regulations and standards which are difficult to interpret and implement, and inspectors who are not conversant with the technology or the issues. A case is demonstrated for a more integrated approach to laser safety, taking into account the development of laser applications, organizational and personnel development, in addition to environmental and occupational health and safety aspects. It is necessary to achieve a harmonization between these elements in any organization involved in laser technology. This might be achieved through establishing technology transfer centres in laser technology.

  2. Laser Scanning Fluorescence Microscope (United States)

    Hansen, Eric W.; Zelten, J. Peter; Wiseman, Benjamin A.


    We report on the development of a laser scanning fluorescence microscope possessing several features which facilitate its application to biological and biophysical analyses in living cells. It is built around a standard inverted microscope stand, enabling the use of standard optics, micromanipulation apparatus, and conventional (including video) microscopy in conjunction with laser scanning. The beam is scanned across the specimen by a pair of galvanometer-mounted mirrors, driven by a programmable controller which can operate in three modes: full raster scan, region of interest, and random-access. A full 512x512 pixel image can be acquired in one second. In region of interest mode, several subareas of the field can be selected for more rapid or detailed analysis. For those cases where the time scale of the observed phenomenon precludes full-field imaging, or where a full-field image is unnecessary, the random access mode enables an arbitrary pattern of isolated points to be selected and rapidly sequenced through. Via a graphical user interface implemented on the system's host computer, a user will be able to take a scout image either with video or a full-field laser scan, select regions or points on the scout image with a mouse, and set up experimental parameters such as detector integration times with a window-style menu. The instrument is designed to be a flexible testbed for investigating new techniques, without compromising its utility as a tool for biological research.

  3. Modeling Quantum Well Lasers

    Directory of Open Access Journals (Sweden)

    Dan Alexandru Anghel


    Full Text Available In semiconductor laser modeling, a good mathematical model gives near-reality results. Three methods of modeling solutions from the rate equations are presented and analyzed. A method based on the rate equations modeled in Simulink to describe quantum well lasers was presented. For different signal types like step function, saw tooth and sinus used as input, a good response of the used equations is obtained. Circuit model resulting from one of the rate equations models is presented and simulated in SPICE. Results show a good modeling behavior. Numerical simulation in MathCad gives satisfactory results for the study of the transitory and dynamic operation at small level of the injection current. The obtained numerical results show the specific limits of each model, according to theoretical analysis. Based on these results, software can be built that integrates circuit simulation and other modeling methods for quantum well lasers to have a tool that model and analysis these devices from all points of view.

  4. Plasmonic colour laser printing (United States)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil; Mortensen, N. Asger; Kristensen, Anders


    Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e-beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours with a speed of 1 ns per pixel, resolution up to 127,000 dots per inch (DPI) and power consumption down to 0.3 nJ per pixel.

  5. Laser-produced microjets (United States)

    Thoroddsen, Sigurdur; Takehara, K.; Etoh, T. G.; Ohl, C.-D.


    We use ultra-high-speed imaging to characterize the formation of a micro-jet when a laser-produced shock hits a bubble sitting under a free surface. The bubble is formed inside a sessile drop, sitting on a glass slide and buoyancy drives it to its top. The jetting is forced by an Nd:YAG-laser pulse of about 30 mJ, focused by a microscope objective sitting under the glass plate. The jet is initiated when the shock hits the curved bottom of the bubble. It emerges out of a bottom crown and has a very regular shape. For water the jets are a few microns in size and can emerge at over 200 m/s. In intermediate viscosity liquids the jetting can be even faster and can emerge at over 500 m/s, depending on the depth of the laser focus. Jets can even be produced in pure glycerin where they emerge at about 100 m/s.

  6. Injectorless quantum cascade lasers (United States)

    Katz, Simeon; Vizbaras, Augustinas; Meyer, Ralf; Amann, Markus-Christian


    This review focuses on recent progress on injectorless quantum cascade lasers, an increasingly attractive approach in comparison to the "classical" injectorbased concepts. This particularly holds for the wavelength range between 7 and 12 μm, where fundamental vibrational modes of many important molecules exist, so that sensor systems for medical, industrial and military applications highly benefit from these laser sources. The atmospheric transmission window between 8 and 12 μm, with very low damping, also enables free space applications like communication, military countermeasures, and environmental sensors. Injectorless devices operate closer to the original design principle for intersubband lasers as suggested by Suris and Kazarinov [Sov. Phys. Semicond. 5, 707 (1971)]. Therefore, a short description of their features is given in comparison to injectorbased devices. Within recent years, injectorless devices have seen rapid improvement in performance. Best injectorless devices reach threshold current densities of 450 A/cm2 at 300 K, a factor of 1.6 smaller than that for the best injectorbased devices. Their output efficiency has also increased from 2% to more than 7% within the last 2 years, reaching comparable levels and making the injectorless device concept competitive and very attractive for applications.

  7. Plasmonic colour laser printing

    DEFF Research Database (Denmark)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil


    Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e-beam lit......Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e......-beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation...... that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours...

  8. LCLS Laser (in Polish)

    CERN Document Server

    Romaniuk, R S


    The most powerful now in the world, American X-ray laser LCLS (Linac Coherent Light Source), has been working as a research and user facility since 2009. It is further developed to LCLSII machine at the Stanford National Accelerator Laboratory SLAC in Menlo Park CA. In a certain sense, LCLS is a response to the EXFEL machine and a logical extension of LCLS. All these machines are light sources of the fifth generation. EXFELis expected to open user facility in 2016, at a cost of over 1 bil Euro. LCLS II, which design started in 2010, will be operational in 2017. The lasers LCLS, LCLS II and EXFEL use SASE and SEED methods to generate light and are powered by electron liniacs, LCLS by a wrm one, and EXFEL by a cold one. The liniacs have energies approaching 20 GeV, and are around 2 - 3 km in length. EXFEL liniac uses SRF TESLA cavity technology at 1,3GHz. A prototype of EXFEL was FLASH laser. SLAC Laboratory uses effectively over 50 years experience in research, building and exploitation of linear electron acce...

  9. Hybrid silicon ring lasers (United States)

    Liang, Di; Fiorentino, Marco; Bowers, John E.; Beausoleil, Raymond G.


    Hybrid silicon platform provides a solution to integrate active components (lasers, amplifiers, photodetectors, etc.) with passive ones on the same silicon substrate, which can be used for building an optical interconnect system. Owing to the advantages in footprint, power consumption, and high-speed modulation, hybrid silicon microring lasers have been demonstrated as a potential candidate for on-chip silicon light source. In this paper we review the progress to improve the performance of recently demonstrated compact microring lasers with ring diameter of 50 μm. A simple approach to enhance optical mode and electron-hole recombination, which results in threshold reduction and efficiency improvement is developed. This is done by appropriately undercutting the multiple quantum well (MQW) region to force carriers to flow towards the outer edge of the microring for better gain/optical mode overlap. We observe a reduction of the threshold of over 20% and up to 80% output power enhancement. The model and the experimental results highlight the benefits, as well as the negative effects from excessive undercutting, including lower MQW confinement, higher modal loss and higher thermal impedance. A design rule for MQW undercutting is therefore provided. Application as on-chip optical interconnects is discussed from a system perspective.

  10. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  11. Laser engineering of spine discs (United States)

    Sobol, E.; Zakharkina, O.; Baskov, A.; Shekhter, A.; Borschenko, I.; Guller, A.; Baskov, V.; Omelchenko, A.; Sviridov, A.


    The laser engineering of intervertebral discs is one of the branch of medical physics aimed at the development of minimally invasive laser medical techniques based on the effect of the controlled (time- and space-modulated) laser radiation on the structure and the field of mechanical stress of biological tissues. A new method for the laser engineering of the intervertebral discs and the differences of this approach from the existing physical methods of medical treatment are considered. The newly formed tissues of animals and humans are hystologically studied. Possible regeneration processes are discussed. A control system that provides for the treatment efficiency and safety is developed. The new laser medical equipment that is designed for the laser engineering of intervertebral discs is described, and the corresponding results of the clinical application are presented.

  12. Scalar - vector soliton fiber lasers

    CERN Document Server

    Wu, Zhichao; Li, Lei; Luo, Yiyang; Tang, Dingyuan; Shen, Deyuan; Tang, Ming; Fu, Songnian; Zhao, Luming


    Rapid progress in passively mode-locked fiber lasers is currently driven by the recent discovery of vector feature of mode-locking pulses, namely, the group velocity-locked vector solitons, the phase locked vector solitons, and the high-order vector solitons. Those vector solitons are fundamentally different from the previously known scalar solitons. Here, we report a fiber laser where the mode-locked pulse evolves as a vector soliton in the strong birefringent segment and is transformed into a regular scalar soliton after the polarizer within the laser cavity. The existence of solutions in a polarization-dependent cavity comprising a periodic combination of two distinct nonlinear waves is novel and likely to be applicable to various other nonlinear systems. For very large local birefringence, our laser approaches the working regime of vector soliton lasers, while it approaches scalar soliton fiber lasers under the conditions of very small birefringence.

  13. Solid-state laser engineering

    CERN Document Server

    Koechner, Walter


    Solid-State Laser Engineering, written from an industrial perspective, discusses in detail the characteristics, design, construction, and performance of solid-state lasers. Emphasis is placed on engineering and practical considerations; phenomenological aspects using models are preferred to abstract mathematical derivations. This new edition has extensively been updated to account for recent developments in the areas of diode-laser pumping, laser materials, and nonlinear crystals. Walter Koechner received a doctorate in Electrical Engineering from the University of Technology in Vienna, Austria, in 1965. He has published numerous papers in the fields of solid-state physics, optics, and lasers. Dr. Koechner is founder and president of Fibertek, Inc., a research firm specializing in the design, development, and production of advanced solid-state lasers, optical radars, and remote-sensing systems.

  14. Solid-State Laser Engineering

    CERN Document Server

    Koechner, Walter


    Written from an industrial perspective, Solid-State Laser Engineering discusses in detail the characteristics, design, construction, and performance of solid-state lasers. Emphasis is placed on engineering and practical considerations; phenomenological aspects using models are preferred to abstract mathematical derivations. Since its first edition almost 30 years ago this book has become the standard in the field of solid-state lasers for scientists,engineers and graduate students. This new edition has been extensively revised and updated to account for recent developments in the areas of diode-laser pumping, laser materials and nonlinear crystals. Completely new sections have been added dealing with frequency control, the theory of mode-locking, femto second lasers, high efficiency harmonic generation, passive and acousto-optic Q-switching, semiconductor saturable absorber mirrors (SESAM) and peridically poled nonlinear crystals.

  15. Pulsed Scophony laser projection system (United States)

    Lowry, J. B.; Welford, W. T.; Humphries, M. R.


    A novel laser TV projection display has been developed by PA Technology employing the Scophony system with acousto-optic modulators and pulsed lasers. This results in a projection system with greater optical simplicity, higher reliability and reduced power and cooling requirements over similar laser projectors. The technique has been successfully implemented in British Aerospace's Microdome missile training simulator. This paper describes the underlying principles of the design, its operational features and its implementation in the Microdome.

  16. Hybrid fiber-rod laser (United States)

    Beach, Raymond J.; Dawson, Jay W.; Messerly, Michael J.; Barty, Christopher P. J.


    Single, or near single transverse mode waveguide definition is produced using a single homogeneous medium to transport both the pump excitation light and generated laser light. By properly configuring the pump deposition and resulting thermal power generation in the waveguide device, a thermal focusing power is established that supports perturbation-stable guided wave propagation of an appropriately configured single or near single transverse mode laser beam and/or laser pulse.

  17. Preprosthetic Laser Assisted Mandibular Vestibuloplasty

    Directory of Open Access Journals (Sweden)

    Kacarska M.


    Full Text Available A prosthetic treatment of the edentulous mandible can be very challenging. In cases with inadequate buccal depth, a necessary deepening of the oral vestibule can be achieved by surgically detaching the soft tissue attachments. A preprosthetic vestibuloplasty is usually done surgically by scalpel. With the permanent advancement of laser technology, a laser vestibuloplasty has become a preferred surgical procedure. The aim of this report was to present individuality of a mandible vestibuloplasty performed with Er.YAG laser.

  18. Optical pulses, lasers, measuring techniques

    CERN Document Server

    Früngel, Frank B A


    High Speed Pulse Technology: Volume II: Optical Pulses - Lasers - Measuring Techniques focuses on the theoretical and engineering problems that result from the capacitor discharge technique.This book is organized into three main topics: light flash production from a capacitive energy storage; signal transmission and ranging systems by capacitor discharges and lasers; and impulse measuring technique. This text specifically discusses the air spark under atmospheric conditions, industrial equipment for laser flashing, and claims for light transmitting system. The application of light impulse sign

  19. A laser pumped quantum discriminator

    Energy Technology Data Exchange (ETDEWEB)

    Budkin, L.A.; Fateev, G.P.; Pikhtelev, A.I.; Puzanov, S.L.


    A method of laser pumping in a quantum discriminator employing alkaline metal vapors is investigated. A good qualitative correlation between computed and experimental relations of the quality parameter on the intensity of laser light is noted. It is demonstrated that the value of the quality parameter of the quantum discriminator with laser pumping may be increased by a factor of at least two compared to a traditional scheme.

  20. Lens Coupled Quantum Cascade Laser (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)


    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  1. Flow visualization by laser sheet


    Chlebanowski, Joseph S., Jr.


    Approved for public release; distribution is unlimited. A flow visualization system using smoke and a laser sheet for illumination has been designed and developed for use in the 32- x 45-inch low speed wind tunnel. Major design features include a portable smoke rake designed for ease of installation and removal, the use of fiber optics to transport the laser light in a safe and convenient manner, and a portable traversing mechanism to traverse and orient the laser light sheet. The capabili...



    Sandesh; Sanajay; Rohit Lakhyani; Shraddanand; Shivaraj


    ABSTRACT: Since the development of the ruby laser by Maiman in 1960, a variety of studies on the potential applications of lasers in dentistry have been conducted. Many applications like computer aided design and rapid prototyping technology, and study of occlusion in complete dentures using three-dimensional laser scanner have been developed. Its applications range from fixed Prosthodontics to treatment of dentinal hypersensitivity to surface treatment of base ...

  3. Laser Cutting of Different Materials

    Directory of Open Access Journals (Sweden)

    Kadir ÇAVDAR


    Full Text Available In this paper; in general potential developments and trends of a particular machining field by extensively evaluating present studies of laser beam machining have been discussed. As it is indicated below, technical literatures have been subsumed under five major headlines: Experimental studies, reviews, optimization researches of the cutting parameters, theoretical modelling studies of laser beam cutting and academic studies relating to laser cutting

  4. Laser Diagnostics for Spacecraft Propulsion (United States)


    Absorption Spectroscopy (DLAS) – Wavelength Modulation Spectroscopy (WMS) • Arcjets • Hall thrusters/Ion engines – Laser Induced Fluorescence (LIF) – Time...technologies • Tunable diode lasers developed in the 1960s – Diagnostic techniques have been developed alongside propulsion technologies – Simulation of – Cut open thruster to examine catalyst • Diode Laser Absorption Spectroscopy – Non-intrusive, in-situ measurements – Temperature, species

  5. Laser Hazards Bibliography - November 1980. (United States)


    July 1968). 111. Paul, J. S., et al., Laser-induced changes in DNA synthesis and embryonic development in sea urchins , Exp Cell Res, 60: 166-174 (May...11. BIOEFFECTS-GENERAL. 1. Baba, K., Selective injury of mitochondria with janus green B and ruby laser light - enzyme morphological and... morphological changes of tissues of the ear concha of a rabbit under the effect of laser rays, Vestn Dermatol Venerol, 0(6): 43-46 (June 1974

  6. [Laser radiations in medical therapy]. (United States)

    Richand, P; Boulnois, J L


    The therapeutic effects of various types of laser beams and the various techniques employed are studied. Clinical and experimental research has shown that Helio-Neon laser beams are most effective as biological stimulants and in reducing inflammation. For this reasons they are best used in dermatological surgery cases (varicose ulcers, decubital and surgical wounds, keloid scars, etc.). Infrared diode laser beams have been shown to be highly effective painkillers especially in painful pathologies like postherpetic neuritis. The various applications of laser therapy in acupuncture, the treatment of reflex dermatologia and optic fibre endocavital therapy are presented. The neurophysiological bases of this therapy are also briefly described.

  7. Development of laser decontamination technique

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Ryuichiro; Fukui, Yasutaka; Tanimoto, Kenichi [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center


    For decommissioning of nuclear fuel facilities, a laser decontamination technique has been developed. The technique was expected to decontaminate high-level radioactive waste to back ground levels, keep the amount of secondary waste low, and be operated by remote control. In the development, a decontamination experiment was executed. Type and operation mode of the laser oscillator, Type and flow rate of the assist gas, repetition rate of the laser pulse, moving velocity of the laser nozzle and irradiation energy were parameters in the experiment. Hot radioactive waste could be decontaminated to background levels uniformly with optimized parameters, which were determined by comparative evaluation. (author)

  8. Semiconductor lasers and herterojunction leds

    CERN Document Server

    Kressel, Henry


    Semiconductor Lasers and Heterojunction LEDs presents an introduction to the subject of semiconductor lasers and heterojunction LEDs. The book reviews relevant basic solid-state and electromagnetic principles; the relevant concepts in solid state physics; and the p-n junctions and heterojunctions. The text also describes stimulated emission and gain; the relevant concepts in electromagnetic field theory; and the modes in laser structures. The relation between electrical and optical properties of laser diodes; epitaxial technology; binary III-V compounds; and diode fabrication are also consider

  9. Laser marking as environment technology (United States)

    Sobotova, Lydia; Badida, Miroslav


    The contribution deals with the laser marking as one of the progressive and environment friendly technologies with utilisation in many branches of industry. Engraving and other types of laser marking of different types of materials are very actual technologies these days. Laser marking decreases the waste creation in comparison with the other classical marking technologies, which use paintings or created chips. In this experimental investigation the laser marking surface texturing of material AL99,7 according to STN 42 4003:1993-08 (STN EN 573) has been conducted. The laser marking machine TruMark 6020 and software TruTops Mark were used. Laser surface texturing after laser marking has been realised under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of engraving or annealing surfaces has been performed using scanning electron microscopy (SEM) technique. The evaluation of roughness of engraved surfaces has been realized according to STN EN ISO 4287 by using Surftest SJ 301. The aim of the contribution was to show how different laser parameters affect the surface texture and colour change of metallic materials while creating minimal waste.

  10. Laser Communications Relay Demonstration Project (United States)

    National Aeronautics and Space Administration — The Laser Communications Relay Demonstration project will advance optical communications technology, expanding industry’s capability to produce competitive,...

  11. Excimer laser drilling of polymers (United States)

    Chen, Yihong; Zheng, HongYu; Wong, Terence K. S.; Tam, Siu Chung


    Laser micro-drilling technology plays a more and more important role in industry, especially in the fabrication of multi-layer electronic packages. In such applications, non- metals are often used as insulators, in which via holes are formed to provide vertical interconnections for densely packed 3D wiring networks. Mechanical punch tools have been the primary means to form holes in ceramic sheets and in polymer boards since the 1970's. As the cost of fabricating punch heads increases drastically and the demand for quick turn around part build becomes more routine, flexible via forming technologies, such as laser drilling, have become more prevalent. In laser drilling, CO2, Nd:YAG, and excimer lasers are often used. Their drilling capabilities, drilling mechanisms, and hole qualities are different because of the different laser beam characteristics such as wavelength and beam energy distribution. In this paper, the mechanisms of laser drilling are briefly reviewed. The results of the experiments on excimer laser drilling of two types of polymer: polyimide and polyethylene terephthalate, are reported. It is found that the etch rate increases with increase of fluence, an the wall angle of drilled holes is dependent on the fluence. The material removal by a laser pulse is highly controllable. There exists an optimal fluence range to obtain clean and smooth edges of quality holes for a given material at a given laser wavelength.

  12. Advances in femtosecond laser technology

    Directory of Open Access Journals (Sweden)

    Callou TP


    Full Text Available Thais Pinheiro Callou, Renato Garcia, Adriana Mukai, Natalia T Giacomin, Rodrigo Guimarães de Souza, Samir J Bechara Department of Ophthalmology, University of Sao Paulo, Sao Paulo, Brazil Abstract: Femtosecond laser technology has become widely adopted by ophthalmic surgeons. The purpose of this study is to discuss applications and advantages of femtosecond lasers over traditional manual techniques, and related unique complications in cataract surgery and corneal refractive surgical procedures, including: LASIK flap creation, intracorneal ring segment implantation, presbyopic treatments, keratoplasty, astigmatic keratotomy, and intrastromal lenticule procedures. Keywords: laser therapy, refractive surgical procedures, intracorneal ring, laser in situ keratomileusis, keratoplasty, presbyopia, cataract extraction, astigmatism surgery

  13. Application of lasers in endodontics (United States)

    Ertl, Thomas P.; Benthin, Hartmut; Majaron, Boris; Mueller, Gerhard J.


    Root canal treatment is still a problem in dentistry. Very often the conventional treatment fails and several treatment sessions are necessary to save the tooth from root resection or extraction. Application of lasers may help in this situation. Bacteria reduction has been demonstrated both in vitro and clinically and is either based on laser induced thermal effects or by using an ultraviolet light source. Root canal cleansing is possible by Er:YAG/YSGG-Lasers, using the hydrodynamic motion of a fluid filled in the canals. However root canal shaping using lasers is still a problem. Via falsas and fiber breakage are points of research.

  14. Laser safety considerations for a mobile laser program (United States)

    Flor, Mary


    An increased demand for advanced laser technology, especially in the area of cutaneous and cosmetic procedures has prompted physicians to use mobile laser services. Utilization of a mobile laser service allows physicians to provide the latest treatments for their patients while minimizing overhead costs. The high capital expense of laser systems is often beyond the financial means of individual clinicians, group practices, free-standing clinics and smaller community hospitals. Historically rapid technology turnover with laser technology places additional risk which is unacceptable to many institutions. In addition, health care reform is mandating consolidation of equipment within health care groups to keep costs at a minimum. In 1994, Abbott Northwestern Hospital organized an in-house mobile laser technology service which employs a group of experienced laser specialists to deliver and support laser treatments for hospital outreach and other regional physicians and health care facilities. Many of the hospital's internal safety standards and policies are applicable to the mobile environment. A significant challenge is client compliance because of the delicate balance of managing risk while avoiding being viewed as a regulator. The clinics and hospitals are assessed prior to service to assure minimum laser safety standards for both the patient and the staff. A major component in assessing new sites is to inform them of applicable regulatory standards and their obligations to assure optimum laser safety. In service training is provided and hospital and procedures are freely shared to assist the client in establishing a safe laser environment. Physician and nursing preceptor programs are also made available.

  15. Semiconductor lasers stability, instability and chaos

    CERN Document Server

    Ohtsubo, Junji


    This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...

  16. Laser program annual report, 1977. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Bender, C.F.; Jarman, B.D. (eds.)


    This volume contains detailed information on each of the following sections: (1) fusion target design, (2) target fabrication, (3) laser fusion experiments and analysis, (4) advanced lasers, (5) systems and applications studies, and (6) laser isotope separation program. (MOW)

  17. CSIR eNews: Laser technology

    CSIR Research Space (South Africa)



    Full Text Available The CSIR provides a critical core of laser technology knowledge and expertise through the research, development and implementation of laser based technologies and applications in Africa. This knowledge, housed at the CSIR National Laser Centre...

  18. CSIR eNews: Laser technology

    CSIR Research Space (South Africa)



    Full Text Available The CSIR provides a critical core of laser technology knowledge and expertise through the research, development and implementation of laser based technologies and applications in Africa. This knowledge, housed at the CSIR National Laser Centre...

  19. Laser welding closed-loop power control

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove


    A closed-loop control system is developed to maintain an even seam width on the root side of a laser weld by continually controlling the output laser power of a 1500 W CO2 laser.......A closed-loop control system is developed to maintain an even seam width on the root side of a laser weld by continually controlling the output laser power of a 1500 W CO2 laser....

  20. Lasers and optoelectronics fundamentals, devices and applications

    CERN Document Server

    Maini, Anil K


    With emphasis on the physical and engineering principles, this book provides a comprehensive and highly accessible treatment of modern lasers and optoelectronics. Divided into four parts, it explains laser fundamentals, types of lasers, laser electronics & optoelectronics, and laser applications, covering each of the topics in their entirety, from basic fundamentals to advanced concepts. Key features include: exploration of technological and application-related aspects of lasers and optoelectronics, detailing both existing and emerging applications in industry, medical diag

  1. Second NASA Conference on Laser Energy Conversion (United States)

    Billman, K. W. (Editor)


    The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

  2. Laser Light: Using Laser Refractometry to Determine Concentration. (United States)

    Gauger, Robert


    Laser refractometry is a science-technology-based activity that requires students to manipulate a variety of equipment, tools, materials, and critical-thinking skills. Students use a laser to measure the percent of glucose in a solution by calibrating the system, taking measurements, and computing the concentration. (MKR)

  3. Lasers and new trends in laser-tissue interaction (United States)

    Serafetinides, Alexandros A.; Papadopoulos, Dimitris N.


    Mid-IR lasers are already used successfully in numerous surgical operations. The Er:YAG and the HF laser, are the main laser sources emitting in the 3.0 μm range of the spectrum, and as this wavelength coincides with the peak of the water and other main soft and hard tissue components absorption curves, it is clear that these lasers would be very useful in numerous medical fields as dentistry, dermatology, angioplasty, ophthalmology etc. Recently, the development of flexible, low loss, able to deliver high power and safe to enter the human body waveguides and fibers for pulsed mid-infrared laser radiation initiated the efforts of the extension of laser surgery in the area of the minimally invasive endoscopy. The laser-induced fluorescence (LIF) is proposed for diagnosis in several pathologies, as in arterial atherosclerosis, in malignancy or for early dental caries detection. LIF is also investigated as a suitable method for monitoring the on line laser surgery interventions.

  4. Paediatric laser dentistry. Part 4: Soft tissue laser applications. (United States)

    Olivi, G; Caprioglio, C; Olivi, M; Genovese, M D


    Lasers can provide effective soft tissues applications in children. All the wavelengths produce incision and vaporisation of oral tissues, together with a high bactericidal effect. The haemosthatic effect varys according to the wavelength used, and the choice of a visibile, near, medium or far infrared laser allows a better interaction with specific targets, gingiva, mucosa, frenum, or oral pathology.

  5. Binding Mechanisms in Selective Laser Sintering and Selective Laser Melting

    NARCIS (Netherlands)

    Kruth, J.P.; Mercelis, P.; Van Vaerenbergh, J.; van Vaerenbergh, J.; Froyen, L.; Rombouts, M.


    Purpose – This paper provides an overview of the different binding mechanisms in selective laser sintering (SLS) and selective laser melting (SLM), thus improving the understanding of these processes. Design/methodology/approach – A classification of SLS/SLM processes was developed, based on the

  6. Laser Plasmas: Multiple charge states of titanium ions in laser ...

    Indian Academy of Sciences (India)

    This paper presents generation and detection of highly stripped titanium ions (Ti) in laser produced plasma. An Nd:glass laser (KAMETRON) delivering 50 J energy ( = 0.53 m) in 2.5 ns was focused onto a titanium target to produce plasma. This plasma was allowed to drift across a space of ∼ 3 m through a diagnostic ...

  7. High power diode lasers for solid-state laser pumps (United States)

    Linden, Kurt J.; Mcdonnell, Patrick N.


    The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

  8. Laser Plasmas: Density oscillations in laser produced plasma ...

    Indian Academy of Sciences (India)

    ... laser intensity in the absence and presence of magnetic field shows appearance of different threshold intensity of laser corresponding to each magnetic field at which this instability or density fluctuation sets on. This instability has been identified as a large Larmor radius instability instead of classical Rayleigh-Taylor (R-T) ...

  9. Laser induced damage threshold on metallic surfaces during laser cleaning

    CSIR Research Space (South Africa)

    Labuschagne, K


    Full Text Available laser paint removal. Laser induced damage on 316L stainless steel was studied, with the target subjected to single and multiple pulse irradiations using a Q-switched Nd:YAG, with fluences between 0.15 and 11.8 J/cm2. Several different damage morphologies...

  10. Influence of laser parameters on laser ultrasonic efficiency

    CSIR Research Space (South Africa)

    Forbes, A


    Full Text Available parameters, such as output couplers and gas mixture, and the impact these choices have on the laser chemistry. The authors present a theory for the catalytic recombination of the gas which shows excellent agreement with experiment. Finally, an operating laser...

  11. Histological difference between pulsed wave laser and continuous wave laser in endovenous laser ablation. (United States)

    Kansaku, Rei; Sakakibara, Naoki; Amano, Atsushi; Endo, Hisako; Shimabukuro, Takashi; Sueishi, Michiaki


    Endovenous laser ablation to saphenous veins has been popular as a minimally invasive treatment for chronic venous insufficiency. However, adverse effects after endovenous laser ablation using continuous wave laser still remain. Pulsed wave with enough short pulse duration and sufficiently long thermal relaxation time may avoid the excess energy delivery, which leads to the perforation of the vein wall. (1) Free radiation: Laser is radiated in blood for 10 s. (2) Endovenous laser ablation: Veins were filled with blood and placed in saline. Endovenous laser ablations were performed. (1) There were clots on the fiber tips with continuous wave laser while no clots with pulsed wave laser. (2) In 980-nm continuous wave, four of 15 specimens had ulcers and 11 of 15 had perforation. In 1470-nm continuous wave with 120 J/cm of linear endovenous energy density, two of three presented ulcers and one of three showed perforation. In 1470-nm continuous wave with 60 J/cm of linear endovenous energy density, two of four had ulcers and two of four had perforation. In 1320-nm pulsed wave, there were neither ulcers nor perforation in the specimens. While endovenous laser ablation using continuous wave results in perforation in many cases, pulsed wave does not lead to perforation. © The Author(s) 2014.

  12. Two-color hybrid laser wakefield and direct laser accelerator (United States)

    Zhang, Xi; Khudik, V.; Bernstein, A.; Downer, M.; Shvets, G.


    We propose and investigate the concept of two-color laser wakefield and direct acceleration (LWDA) scheme in the regime of moderate (10 TW scale) laser powers. The concept utilizes two unequal frequency laser pulses: the leading long-wavelength (λ0 = 0.8 µm) wakefield laser pulse driving a nonlinear plasma wake, and a trailing short-wavelength (λDLA = λ0/2) DLA laser pulse. The combination of the large electric field, yet small ponderomotive pressure of the DLA pulse is shown to be advantageous for producing a higher energy and larger charge electron beam compared with the single frequency LWDA. The sensitivity of the dual-frequency LWDA to synchronization time jitter is also reduced.

  13. Laser-plasma lens for laser-wakefield accelerators

    Directory of Open Access Journals (Sweden)

    R. Lehe


    Full Text Available Thanks to their compactness and unique properties, laser-wakefield accelerators are currently considered for several innovative applications. However, many of these applications—and especially those that require beam transport—are hindered by the large divergence of laser-accelerated beams. Here we propose a collimating concept that relies on the strong radial electric field of the laser-wakefield to reduce this divergence. This concept utilizes an additional gas jet, placed after the laser-wakefield accelerator. When the laser pulse propagates through this additional gas jet, it drives a wakefield which can refocus the trailing electron bunch. Particle-in-cell simulations demonstrate that this approach can reduce the divergence by at least a factor of 3 for realistic electron bunches.

  14. Resonant Laser Incisions: Molecular Targets Using the Free Electron Laser (United States)

    Reinisch, Lou; Bryant, Grady; Ossoff, Robert H.


    Laser ablation of tissue for medical incisions is normally concerned with the energy absorption and the subsequent vaporization of intracellular water. Using Fourier transform infrared spectroscopy, we have identified specific non-water resonances within tissues. Then, using the Vanderbilt Free Electron Laser (wavelength tunable from 2 to 10 microns) and our Computer Assisted Surgical Techniques program (to standardize the laser delivery), we have targeted specific molecular resonances for laser incisions and tissue removal. Using both acute and chronic studies, we can map out the resonant action spectrum to improve surgical outcomes. We have modeled these ablation mechanisms and working to establish the link between these ablation mechanisms and wound healing. This work has been supported, in part, by a grant from the Department of Defense, Medical Free Electron Laser Program, ONR Grant #N000149411023.

  15. Laser Technology in Peace and War. (United States)

    Bloembergen, N.

    Lasers emit light with a very high degree of monochromaticity, directionality and intensity. They can produce much higher intensities than incoherent light sources, such as incandescent lamps, fluorescent tubes and arcs. The first operating laser was realized in 1960, and much early research was funded by military agencies, but at the present time the commercial laser market is four times as large as the military market. Most applications of lasers are for peaceful purposes. Among the most important of these are fiber-optic communications and laser surgery. Other applications include laser printing, laser machining, construction alignment, and data storage on CD disks. Some military uses of lasers are also reviewed.

  16. Laser light scattering basic principles and practice

    CERN Document Server

    Chu, Benjamin


    Geared toward upper-level undergraduate and graduate students, this text introduces the interdisciplinary area of laser light scattering, focusing chiefly on theoretical concepts of quasielastic laser scattering.

  17. High Energy Solid State Laser Research Facility (United States)

    Federal Laboratory Consortium — A suite of laboratories with advanced spectroscopic and laser equipment, this facility develops materials and techniques for advanced solid state high energy lasers....

  18. The Mercury Laser Advances Laser Technology for Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Ebbers, C A; Caird, J; Moses, E


    The National Ignition Facility (NIF) at Lawrence Livermore Laboratory is on target to demonstrate 'breakeven' - creating as much fusion-energy output as laser-energy input. NIF will compress a tiny sphere of hydrogen isotopes with 1.8 MJ of laser light in a 20-ns pulse, packing the isotopes so tightly that they fuse together, producing helium nuclei and releasing energy in the form of energetic particles. The achievement of breakeven will culminate an enormous effort by thousands of scientists and engineers, not only at Livermore but around the world, during the past several decades. But what about the day after NIF achieves breakeven? NIF is a world-class engineering research facility, but if laser fusion is ever to generate power for civilian consumption, the laser will have to deliver pulses nearly 100,000 times faster than NIF - a rate of perhaps 10 shots per second as opposed to NIF's several shots a day. The Mercury laser (named after the Roman messenger god) is intended to lead the way to a 10-shots-per-second, electrically-efficient, driver laser for commercial laser fusion. While the Mercury laser will generate only a small fraction of the peak power of NIF (1/30,000), Mercury operates at higher average power. The design of Mercury takes full advantage of the technology advances manifest in its behemoth cousin (Table 1). One significant difference is that, unlike the flashlamp-pumped NIF, Mercury is pumped by highly efficient laser diodes. Mercury is a prototype laser capable of scaling in aperture and energy to a NIF-like beamline, with greater electrical efficiency, while still running at a repetition rate 100,000 times greater.

  19. Topological defect lasers

    CERN Document Server

    Knitter, Sebastian; Xiong, Wen; Guy, Mikhael I; Solomon, Glenn S; Cao, Hui


    We demonstrate topological defect lasers in a GaAs membrane with embedded InAs quantum dots. By introducing a disclination to a square-lattice of elliptical air holes, we obtain spatially confined optical resonances with high quality factor. Such resonances support powerflow vortices, and lase upon optical excitation of quantum dots, embedded in the structure. The spatially inhomogeneous variation of the unit cell orientation adds another dimension to the control of a lasing mode, enabling the manipulation of its field pattern and energy flow landscape.

  20. Laser Technologies in Industry. (United States)


    400$00 q 9 60000 q G HOTEL V V BOA -VISTA 4 stars G 5 200$00 6 400$00 g INCA HOTEL BOEGA C q Special rates could be extend to members of the family and...Industrial Azinhaga dos Lameiros A Estrada do Paso do Lumiar 1699 Lisboa Codex The Laser Cutting System applied to marble presents several advantages...Lemos, N. Ribau Teixeira LMTX/DEK (6PTICA) Azinhaga dos Lameiros A Estrada do Pago do Lumiar 1699 LISBOA Codex For applications like remote sensing