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...

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...

JLA Vol:9 Iss:3 (A power distribution model of industrial CO₂ 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‐flow d.c.‐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‐in/ramp‐out rates. Many of these factors which occur in ...

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...

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‐contact dimensional metrology. However, there are several factors which must be taken int...

JLA Vol:15 Iss:2 (Plasma assisted laser surface alloying)

Authors:
M. H. McCay
C. M. Sharp
J. A. Hopkins
The Center for Laser Applications, The University of Tennessee Space Institute, Tullahoma, Tennessee 37388

B. Szapiro
The Department of Physics, University of the South, Sewanee, Tennessee

T. D. McCay
The Center for Laser Applications, The University of Tennessee Space Institute, Tullahoma, Tennessee 37388

The combination of plasma arc with a Nd:YAG laser during surface alloying produces a synergistic effect which significantly increases the depth of the melt pool beyond that expected by a summation of the individual depths. Incremental increases in laser power produce ...

JLA Vol:8 Iss:1 (Laser polarimeters: Overview of recent developments, design and applications)

Authors:
Vi´ctor Fajer Avila
Center for the Development of Scientific Equipment and Instruments, Ministry of Science Techonology and Environment, Havana, Cuba

Research carried out in Cuba has led to the design and construction of automatic polarimeters that use the He‐Ne laser as a luminous source and work on a magnetooptic principle of measurement. Physical and chemical investigations including the use of the He‐Ne laser as a light source are discussed. The principle of measurement for the design and construction of polarimeters, resulting in three different types of these instruments, is described. Finally, applications for magnetooptic polarimetry are described,...

JLA Vol:19 Iss:3 (Femtosecond pulsed laser microfabrication of SiC MEMS microgripper)

Authors:
Monica Vendan
Pal Molian
Mechanical Engineering Department, Iowa State University, Ames, Iowa 50011

We report the capability of an ultrafast laser to pattern an electrostatic-comb-drive microgripper in the chemically difficult-to-etch 3C-SiC thin films. A microgripper with overall dimensions 1.2 mm×0.35 mm and a gap of 20 μm was designed and fabricated for the purpose of grasping and transporting microscale objects in hostile and harsh environments. Atmospheric pressure chemical vapor deposition was used to deposit thin films (∼2 μm) of 3C-SiC on 〈100〉 silicon substrates. A Ti:sapphire laser with 120 fs pulse wid...

JLA Vol:3 Iss:1 (Laser Welding Copper and Copper Alloys)

Authors:
Kaoru Hashimoto
Takehiko Sato
Koichi Niwa
Fujitsu Laboratories Ltd., 10‐1, Morinosato‐Wakamiya, Atsugi 243‐01, Japan

We have developed a laser hermetic sealing technique that combines nickel plating with laser welding for copper and copper alloy bellows for general purpose large‐scale computers. Laser welding of copper has been difficult because of copper's high thermal conductivity and reflectivity. However, laser welding nickel‐plated copper results in deep penetration. To avoid corrosion induced at the dissimilar metal contact between nickel and copper, the nickel‐plated copper was heat‐treated bef...

JLA Vol:25 Iss:4 (On the exposure limits for extended source multiple pulse laser exposures)