• JLA Vol:7 Iss:1 (Taking advantage of laser properties to enhance demonstrations and student laboratories)


    Authors:
    Michele L. Brill
    Camden County College—Physics/Lasers, Box 200, Blackwood, NJ 08012, U.S.A.


    This paper reflects the proceedings of a workshop for local educators provided by Camden County College Laser Curriculum faculty which addressed the question: ‘How can the teacher take advantage of laser properties to improve or enhance demonstrations and student labs?’ Explored here are illustrative ways in which to utilize, for educational purposes, the three well‐known characteristics of lasers: monochromaticity, directionality, and coherence. There is a faculty overlap between the Physics Department and the Laser Curriculum faculty at the college. The use o...

    $25.00

  • JLA Vol:16 Iss:2 (Investigation of weld cracking in Nd:yttrium–aluminum–garnet keyhole spot welding of materials used in optoelectronic packaging)


    Authors:
    Geoff J. Shannon
    Unitek Miyachi Corporation, 1820 S. Myrtle Avenue, Monrovia, California 91017

    Bernard Q. Li
    Honeywell VCSEL Optical Division, Minnesota


    The welding of a problematic optical device weld joint between dissimilar materials is investigated in depth. The original material combination of cold rolled steel 1010 with 6 μm of gold coating and 304 L produced consistent weld cracking. The CRS1010 material was fixed, however the other component was open to material selection. The materials tested were 304 L stainless steel, kovar, invar, and Carpenter high permeability 49 alloy. The effect of these different materials, laser pulse parameters, lev...

    $25.00

  • JLA Vol:20 Iss:4 (Thermal stress analysis on laser scribing of glass)


    Authors:
    Koji Yamamoto
    Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan

    Noboru Hasaka
    Hideki Morita
    Mitsuboshi Diamond Industrial Co., Ltd., 2-12-12 Minami-Kaneden, Suita, Osaka, Japan

    Etsuji Ohmura
    Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan


    In the laser scribing of glass a thermal stress is introduced into a glass substrate by means of a CO2 laser irradiation. The glass substrate is then rapidly cooled down by water jet immediately after the irradiation. For the purpose of theoretical clarification of the factors ruling the scribable condit...

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  • JLA Vol:9 Iss:3 (A power distribution model of industrial CO<sub>2</sub> lasers for system diagnosis)


    Authors:
    James G. Katter
    Jay F. Tu
    Mark Gartner



    Industrial lasers are high power pieces of equipment that occasionally function under undesirable operating conditions. For example, the performance of a transverse&hyphen;flow d.c.&hyphen;excited gas laser can be adversely affected by many factors such as electrode arcing, poor lens and mirror cleanliness, focusing problems, improper gas mixture composition, poor gas quality, poor beam stability, poor beam path cleanliness, operator error, poor maintenance, poor chiller water temperature and flow rate stability, and improper laser beam ramp&hyphen;in/ramp&hyphen;out rates. Many of these factors which occur in ...

    $25.00

  • JLA Vol:4 Iss:1 (Laser Triangulation Range Sensors: A Study of Performance Limitations)


    Authors:
    Michael Buzinski
    Alan Levine
    Warren H. Stevenson
    Applied Optics Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907


    Optical triangulation is a very old method of determining absolute distance to an object. In recent years laser range sensors utilizing this principle have seen growing use, particularly in the auto industry. More accurate versions are being employed for dimensional inspection operations where the sensor is often mounted on a coordinate measuring machine. Such a system offers the potential for rapid non&hyphen;contact dimensional metrology. However, there are several factors which must be taken int...

    $25.00

  • JLA Vol:14 Iss:4 (High-energy femtosecond pulsed laser micromachining of thin film deposited silicon in self-focused air medium)


    Authors:
    Yuanyuan Dong
    Pal Molian
    Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011

    Christian Zorman
    Mehran Mehregany
    Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, Ohio 44106


    The ultrashort pulsed laser ablation of silicon wafers deposited with 1 μm thin film of SiC was performed in air medium using a 1 mJ, 120 fs, 800 nm Ti:sapphire laser, the objective being to determine the self-focusing capability of air to produce nanostructures. The effects of pulse energy, the number of pulses, pulse repetition rate and x–y translation speed on t...

    $25.00

  • JLA Vol:18 Iss:4 (Threshold powers and delays for igniting propane and butane-air mixtures by cw laser-heated small particles)


    Authors:
    Thomas H. Dubaniewicz
    National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236


    The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory conducted a study of laser safety in potentially flammable environments. Researchers measured threshold igniting powers as a function of beam diameter for butane and propane-air mixtures by laser-heating targets placed on optical fiber tips using a 1064 nm laser. The minimum igniting powers for propane-air and butane-air were about 250 and 300 mW, respectively. Threshold igniting powers for propane-air were approxima...

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  • JLA Vol:7 Iss:4 (Laser applications in science education (LASE) Project: an introduction to photonics at the secondary school level)


    Authors:
    Gareth T. Williams
    Physics Department, San Jose State University, San Jose, California, U.S.A.


    $25.00

  • JLA Vol:17 Iss:1 (Microstructural characterization of dissimilar laser weld between austenitic and ferritic stainless steels)


    Authors:
    Rakesh Kaul
    P. Ganesh
    A. K. Nath
    Industrial CO2 Laser Section, Centre for Advanced Technology, P. O. CAT, Indore 452 013, India


    The present work involved microstructural characterization of thin sheet dissimilar laser welds between type 304 austenitic stainless steel and stabilized 17% Cr ferritic stainless steel and their comparison with welds produced by autogenous gas tungsten arc welding (GTAW). Low heat input of laser welding (LW) effectively reduced the size of fusion zone (FZ) and heat affected zone (HAZ). LW with focused laser beam (LB), preferentially displaced towards austenitic stainless steel (ASS), produced FZ with uniform and highly ref...

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  • JLA Vol:21 Iss:3 (Infrared observations and finite element modeling of a laser transmission welding process)


    Authors:
    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 (LTW), a technique to join thermoplastic components, involves a laser beam passing through a laser-transmitting part and then being absorbed by the laser-absorbing part at the weld interface. To form a strong bond, it is important that the weld interface be exposed to sufficient heat to melt the polymer without degrading it. A lap-joint geometry was investigated and the...

    $25.00

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