JLA Vol:7 Iss:1 (Photodynamic therapy)

Authors:
Leonard I. Grossweiner
Physics Department, Illinois Institute of Technology, Chicago, IL 60616 and Wenske Laser Center, Ravenswood Hospital Medical Center, Chicago, IL 60664, U.S.A.

Photodynamic therapy (PDT) is a new treatment for solid tumors utilizing the combined action of light and a photosensitizing drug. Laser–fiber optic delivery systems make it practical to treat superficial and interstitial cancers, including malignancies of the skin, head and neck, esophagus, endobronchial tract, stomach, urinary bladder, female genital tract, and other sites. The putative action mechanism in PDT involves photochemical destruction of tumor tissue membranes mediated by singlet...

JLA Vol:7 Iss:1 (Safe laser system design for production)

Authors:
Ami Kestenbaum
Richard J. Coyle
Patrick P. Solan
AT&T Bell Laboratories Engineering Research Center, Princeton, NJ 08542‐0900, U.S.A.

The majority of industrial lasers used in manufacturing are Class IV lasers. Engineering and administrative control measures appropriate to that class of lasers must be enforced to ensure their safe use in production environments, i.e. they should be designed into Class 1 laser systems. In addition, several other design characteristics unique to industrial applications are normally incorporated into these Class I systems, such as interlocked enclosures, process mon...

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...

JLA Vol:7 Iss:1 (Ultrasonic vibration aided laser welding of Al alloys: improvement of laser welding‐quality)

Authors:
J. S. Kim
T. Watanabe
Y. Yoshida

Using a pulsed YAG laser, meltability of Al‐Mg and Al‐Mg‐Si alloys were investigated by a single‐pass irradiation. In order to improve the quality in laser welding, the effectiveness of the Ultrasonic Vibration Laser Welding (UVLW) method proposed in this paper was investigated experimentally. The proposed method was also compared with the traditional welding methods of Normal Laser Welding (NLW) and preHeating Laser Welding (HLW). The welding methods were evaluated from the geometry in the melt zone generated by a single pulse of the laser beam. It was suggested that ultrasonic vibration ...

JLA Vol:7 Iss:2 (A study of polarization‐maintaining fiber characteristics with applications to force and displacement sensing)

Authors:
P. V. P. Yupapin
K. Weir
K. T. V. Grattan
A. W. Palmer

An experimental investigation of three different types of highly birefringent fiber sensor element configured as a force and a displacement sensor is described. From the coupling of power between the two eigenmodes, the magnitude of the force and the position of the coupling point can then be determined using ‘white‐light interferometric’ techniques.

JLA Vol:7 Iss:2 (Fiber optic equipment to supplement today's laser electro‐optic laboratories and global communication highway)

Authors:
Thomas A. Cellucci
Newport Corporation, 1791 Deeve Ave., Irvine, CA 92714, U.S.A.

As the key technology of the Information Superhighway, fiber optics is poised for explosive growth in the next decade. This paper identifies some of the major obstacles involved in establishing a university‐level fiber optics laboratory, and suggests time‐and money‐saving solutions with an emphasis on pre‐packaged fiber optic laboratory kits.

JLA Vol:7 Iss:2 (Fraunhofer resource center for laser technology ‐ USA)

Authors:
Frank W. Kuepper
Fraunhofer Resource Center for Laser Technology, Ann Arbor, MI, U.S.A.

JLA Vol:7 Iss:2 (Fraunhofer‐Institut fu¨r Lasertechnik)

Authors:
Eckhard Beyer
Fraunhofer‐Institut fu¨r Lasertechnik, Aachen, Germany

JLA Vol:7 Iss:2 (Hazardous emissions: characterization of CO₂ laser material processing)

Authors:
H. Haferkamp
M. Goede
K. Engel
J.‐S. Wittbecker
Laser Zentrum Hannover e.V., Hollerithallee 8, D‐3000 Hannover 21, Germany

Parallel to the growth of laser technology is a high interest in safety in industrial surroundings. The characteristics of hazards resulting from laser processing are complex and highly interdependent. In addition, very little fundamental scientific research on this topic exists. The Laser Zentrum Hannover e.V. (LZH) is working on a research project subsidized by the BMFT (German Federal Ministry for Research and Technology) concerning the characterization and reduction of hazardous emissions resulting ...

JLA Vol:7 Iss:2 (High‐speed photographic studies of laser drilling of ceramics and ceramic composites)

Authors:
S. Ramanathan
M. F. Modest
Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802, U.S.A.

High‐speed photographic techniques were used to study plumes generated above a material during drilling of ceramics and ceramic composites with a carbon dioxide laser. The prinicipal objectives were to identify the mechanism of material removal (spattering, particulate and fiber debris, liquid droplets) and plume phenomena (plume shapes and sizes) for ceramics and ceramic composites. High‐speed photographic (1000 frames per second) visualization of laser drilling was undertaken for two monolithic ceramics, (sintered &...