JLA Vol:23 Iss:2 (Model of the atom laser with Raman outcoupling)

Authors:
Chasib A. Emshary
Shaker I. Esa
Department of Physics, College of Education, Basrah University, Basrah, Iraq

Arafat J. Almanea
Department of Physics, College of Science, Basrah University, Basrah, Iraq

In the present paper, the authors start from the interaction of a system of two-level atoms with an electromagnetic field to drive the interaction Hamiltonian between these two-level atoms. Second, introduce the equations of motion which describing the dynamics of atom laser depending on the interaction Hamiltonian, this interaction Hamiltonian will be used to describe the outcoupling process in a Raman atom laser. Also, the authors model the ...

JLA Vol:23 Iss:2 (Recent advances in laser surface treatment of titanium alloys)

Authors:
J. J. Candel
V. Amigo´
ITM Instituto de Tecnologia de Materiales, UPV, Valencia, Spain

This paper reviews progress over the last five years in the field of laser surface modification of titanium alloys. The authors analyze the effect of new laser technologies and new materials as tools for improving surface properties—specifically, biocompatibility and resistance to wear, corrosion, and high temperatures. The authors discuss the effect of laser processing parameters on the microstructure and compare the results obtained by various researchers. Therefore, an overview of the difficulties involved in the laser processing of titanium is provided with a di...

JLA Vol:23 Iss:2 (Surface texturing by laser cladding)

Authors:
A. Grueninger
M. Hustedt
D. Herzog
M. Huse
D. Kracht
H. Haferkamp
Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover, Germany

A. Ostendorf
Lehrstuhl fuer Laseranwendungstechnik, Ruhr-Universitaet Bochum, Universitaetsstr. 150, D-44780 Bochum, Germany

Surface texturing is an established method for altering the structure of a surface. All known methods deal with material removal. For applications where only small walls remain on the surface, this means that most of the surface must be treated. In this paper, a new approach is presented in which texturing and laser cladding are co...

JLA Vol:23 Iss:2 (Welding of thick stainless steel plates up to 50 mm with high brightness lasers)

Authors:
Xudong Zhang
Eiji Ashida
Hitachi, Ltd., Materials Research Lab., Hitachi, Ibaraki, 319–1292 Japan

Shoh Tarasawa
Yusuke Anma
Masaya Okada
Hitachi-GE Nuclear Energy, Ltd., Hitachi, Ibaraki, 319–1221 Japan

Seiji Katayama
Masami Mizutani
Joining and Welding Research Institute, Osaka University, Osaka, 567–0047 Japan

Thick-section stainless steels are widely used in the components and structures for nuclear power plants. Laser welding is being considered as a high-efficiency method instead of arc welding for some components, so as to improve the production efficiency ...

JLA Vol:23 Iss:3 (Effect of Q-switched pulses exposure on morphology, hydroxyapatite composition, and microhardness properties of human enamel)

Authors:
R. Apsari
Department of Physics, Faculty of Sciences and Technology, Airlangga University, 60115 Surabaya, Indonesia

Noriah Bidin
Aminatun Suhariningsih
Department of Physics, Faculty of Sciences and Technology, Airlangga University, 60115 Surabaya, Indonesia

Sri Hartati
Department of Physics, Faculty of Mathematics and Natural Sciences, Gadjah Mada University, 55281 Yogyakarta, Indonesia

Anita Yuliati
Department of Dental Material, Faculty of Dentistry, Airlangga University, 60131 Surabaya, Indonesia

M. Yasin
Department of Physics, Faculty of Sciences and Technology, Airlangga University, 6011...

JLA Vol:23 Iss:3 (Innovative approach of joining hybrid components)

Authors:
Andreas Roesner
Fraunhofer Institute for Laser Technology, Aachen, Steinbachstr. 15, 52074 Aachen, Germany

Sven Scheik
Welding and Joining Institute, RWTH Aachen University, Pontstr. 49, 52062 Aachen, Germany

Alexander Olowinsky
Arnold Gillner
Reinhart Poprawe
Fraunhofer Institute for Laser Technology, Aachen, Steinbachstr. 15, 52074 Aachen, Germany

Markus Schleser
Uwe Reisgen
Welding and Joining Institute, RWTH Aachen University, Pontstr. 49, 52062 Aachen, Germany

Joining of dissimilar materials is gaining more and more importance especially in the automotive industry. Th...

JLA Vol:23 Iss:3 (Optimization of UV laser scribing process for light emitting diode sapphire wafers)

Authors:
Ashwini Tamhankar
Rajesh Patel
Spectra-Physics Lasers, Newport Corporation, 3635 Peterson Way, Santa Clara, California 95054

Billions of light emitting diodes (LEDs) are used today in traffic control, automotive headlights, flat panel display technology, mobile devices, back lighting, projection, and general illumination applications. With the dramatic growth in LEDs, manufacturers are looking for technologies to increase production yield and decrease cost. Sapphire wafer singulation into miniature dies is one of the critical steps used in blue LED manufacturing. Typical dicing techniques used in wafer singulation process include laser dicing, laser scribing and ...

JLA Vol:23 Iss:3 (Parameter optimization of a laser-induced fluorescence system for <em>in vivo</em> screening of oral cancer)

Authors:
V. K. Unnikrishnan
Rajesh Nayak
Rodney Bernard
Centre for Atomic and Molecular Physics, Manipal University, Manipal, 576 104, India

K. Jeena Priya
Department of Oral Medicine and Radiology, MCODS Mangalore, Manipal University, Manipal, 575 001, India

Ajeetkumar Patil
Centre for Atomic and Molecular Physics, Manipal University, Manipal, 576 104 India

J. Ebenezer
PG & Research Department of Physics, Jamal Mohamed College, Tiruchinapalli, Manipal, 620 020, India

Keerthilatha M. Pai
Department of Oral Medicine and Radiology, MCODS Manipal, Manipal University, Manipal,576 104 India<...

JLA Vol:23 Iss:3 (Spatter in laser welding)

Authors:
A. F. H. Kaplan
J. Powell
Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-971 87 Luleå, Sweden

Spatter, the ejection of melt from a weld pool, is a major problem whenever it occurs in a welding process. The ejection of droplets from the weld metal results in a weld with underfill, undercuts, craters, blowholes, or blowouts—all of which can have a detrimental effect on the mechanical properties of the weld. This paper presents a systematic description of the different types of spatter phenomena which occur during laser welding. A categorization system is proposed to facilitate the comparison and combination ...

JLA Vol:23 Iss:3 (The effect of multiple laser alloyed tracklines on the corrosion properties of Al-MMC)

Authors:
Patricia A. I. Popoola
Faculty of Engineering and the Built Environment, Tshwane University of Technology, P.M.B. X680, Pretoria 0001, South Africa

Sisa L. Pityana
Faculty of Engineering and the Built Environment, Tshwane University of Technology, P.M.B. X680, Pretoria 0001, South Africa and Centre for Scientific and Industrial Research-National Laser Centre, P.O. Box 395, Pretoria 0001, South Africa

Olawale M. Popoola
Faculty of Engineering and the Built Environment, Tshwane University of Technology, P.M.B X680, Pretoria 0001, South Africa

In real life engineering applications, production of large area coverage is often required es...