• JLA Vol:19 Iss:1 (Procedure for the computation of hazards from diffusely scattering surfaces under the Z136.1-2000 American National Standard for Safe Use of Lasers)

    Robert J. Thomas
    Benjamin A. Rockwell
    Air Force Research Laboratory, Brooks AFB, Texas 78235-5128

    Wesley J. Marshall
    USACHPPM, Aberdeen Proving Ground, Maryland 21010-5403

    Robert C. Aldrich
    Mary F. Gorschboth
    Sheldon A. Zimmerman
    Dahlgren Division, Naval Surface Warfare Center, Dahlgren, Virginia 22448-5100

    R. James Rockwell
    Rockwell Laser Industries, Cincinnati, Ohio 45243

    The current national consensus standard for laser safety in the United States is the American National Standard for Safe Use of Lasers (ANSI Z136.1). The most recent standard, Z136.1-2000, incorporates ...


  • JLA Vol:24 Iss:1 (Hazard class downscaling of a class 4 retina safe laser)

    Jed A. Simmons
    Alan B. Marchant
    Energy Dynamics Laboratory, North Logan, Utah 84341

    A class 4 pulsed laser can be operated in a safe regime without reducing instantaneous irradiance or pulse energy by shortening its dwell time through duty cycle reduction or scanning. A conservative relationship for hazard distance as a function of scan rate is derived for the case of a scanning, retina safe laser.


  • JLA Vol:6 Iss:3 (Attenuation of laser radiation by particles during laser materials processing)

    F. Hansen
    W. W. Duley
    Guelph‐Waterloo Centre for Graduate Work in Physics, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

    The extinction, absorption and scattering of laser radiation by small aerosol particles of Fe, Fe3O4, Al, and Al2O3 have been calculated using Mie theory at wavelengths of 1.06 and 10.6 μm. It is shown that the attenuation of incident laser radiation by particles with radii r in the range 10 nm ⩽ r ⩽ 10 μm can be significant over pathlengths as small as 10−2 m when the ratio of aerosol mass density to solid density, M/ρ &...


  • JLA Vol:17 Iss:3 (High-speed scanning laser-induced breakdown spectroscopy at 1000 Hz with single pulse evaluation for the detection of inclusions in steel)

    Holger Bette
    Reinhard Noll
    Fraunhofer-Institut fu¨r Lasertechnik (ILT), Steinbachstr. 15, 52074 Aachen, Germany

    Gregor Mu¨ller
    Hans-Werner Jansen
    C¸etin Nazikkol
    Horst Mittelsta¨dt
    ThyssenKrupp Stahl AG, Kaiser-Wilhelm-Str. 100, 47166 Duisburg, Germany

    Spatially resolved information about the distribution and chemical composition of inclusions in steel are gained by scanning methods, such as scanning electron microscopy with energy dispersive X-ray spectroscopy, electron probe microanalysis or capillary-X-ray flourescence. Scanning laser-induced breakdown spectroscopy (LIBS) offers dis...


  • JLA Vol:22 Iss:1 (Finite volume model for laser-soot interaction for a laser transmission welding process)

    L. S. Mayboudi
    A. M. Birk
    G. Zak
    Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada

    P. J. Bates
    Chemistry and Chemical Engineering, Royal Military College, Kingston, Ontario K7K 7B4, Canada

    Laser transmission welding, a technique to join thermoplastic components, involves a laser beam passing through a laser-transmitting part being absorbed by a laser-absorbing part at the weld interface. The heat generated at the interface melts a thin layer of the plastic in both parts and forms a joint. Laser-absorbing agents such as dyes or soot particles are added to the laser-absorbing part to...


  • JLA Vol:8 Iss:4 (Acoustic emission from modulated laser beam welding of materials)

    Hongping Gu
    W. W. Duley
    Guelph‐Waterloo Program for Graduate Work in Physics, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

    Acoustic emission during the laser welding of metals with a modulated CO2 laser beam has been investigated. Sharp resonances at many frequencies in the acoustic emission spectra have been observed. This was most noticeable when the average laser power was high enough to produce full penetration welds whose acoustic emission at high harmonics with frequencies that overlap with bands of vibrational frequencies corresponding to eigenmodes of the keyhole are greatly enhanced. Lower harmonics were not clearly observe...


  • JLA Vol:2 Iss:2 (Infrared Optical Fibers for Surgical Applications)

    R. W. Waynant
    M. N. Ediger
    M. Fink
    Center for Devices and Radiological Health, Food and Drug Administration, 5600 Fishers Lane, Rockville, MD 20857

    The basic characteristics of fibers that are appropriate for surgical use in the infrared are reviewed. New fiber materials, such as sapphire, fluorozirconate and chalcogenide glasses, and polycrystalline fibers are discussed as well as their applicability for surgical procedures.


  • JLA Vol:26 Iss:1 (Evolution of nano-ripples on stainless steel irradiated by picosecond laser pulses)

    Bin Liu
    Wenjun Wang
    Gedong Jiang
    Xuesong Mei
    Kedian Wang
    Jiuhong Wang
    Zibao Wang
    State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an 710054, China

    The characteristics of laser-induced periodic surface structures are investigated after laser irradiation with a pulse duration (10 ps) under a certain laser fluence (0.27 J/cm2) and pulse number (N = 50–2000). In the experiments, at the lowest number of pulses, ultrafine ripples are observed with sub-200-nm spatial periods and an orientation parallel to laser polarization ...


  • JLA Vol:15 Iss:4 (Excimer laser fabrication of polymer microfluidic devices)

    Joohan Kim
    Xianfan Xu
    School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907

    Silicon has been a primary material for fabrication of microelectromechanical systems (microfluidic devices in MEMS) for several decades. This is due to the fact that the MEMS techniques were derived from those used for microfabrication in the semiconductor industry. These techniques are well developed, and can be readily applied for silicon based MEMS fabrication. Nowadays, alternative manufacturing materials and techniques are needed for reducing costs and meeting new requirements. Polymers have many advantages because of their low costs and applications in ...


  • JLA Vol:20 Iss:1 (Dynamic bidirectional reflectance distribution functions: Measurement and representation)

    Albert W. Bailey
    Edward A. Early
    Kenneth S. Keppler
    Victor I. Villavicencio
    Northrop Grumman, 4241 Woodcock Drive, Suite B-100, San Antonio, Texas 78238

    Paul Kennedy
    Robert J. Thomas
    Justin J. Zohner
    Human Effectiveness Directorate, Directed Energy Bioeffects Division, Optical Radiation Branch, Air Force Research Laboratory, 2624 Louis Bauer Drive, Brooks City-Base, Texas 78235

    George Megaloudis
    Northrop Grumman, 100 Brickstone Square, Andover, Massachusetts 01810

    With high-energy lasers, not only the direct laser beam can pose significant eye and skin hazards, but als...



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