TABLE OF CONTENTS In order to fulfil the LSP process requirements, it is very important to select a suitable laser system, which normally requires an average power level of from several hundreds watts to kilowatts, a pulse energy of around 100 J and a pulse duration of around 30 ns. In addition, both a high repetition rate of the laser pulse and a reasonable laser wavelength are also important for LSP to assure effective treatment results for metal components. Selecting a laser system for LSP application not only requires these physical characteristics of the laser source, but also needs to consider some specific requirements such as cost, efficiency, maintenance and part replacements and so on.
The neodymium-doped glass (Nd-glass) laser was initially developed in 1974 at Battelle Columbus Laboratories (BCL) Ohio. It was quite cumbersome, about 150 ft long (though powerful, >500 J per pulse), and its repetition rate was extremely slow, about one cycle every 8 min. Later, based on this technology, BCL sponsored by Wagner Laser Technologies (WLT) invented a 4 6 ft (~1.2 1.8 m) glass-laser system capable of 100 J or so, with a repetition rate of 1 Hz, or one cycle per second (cps) (Vaccari, 1992). The Lawrence Livermore National Laboratory (LLNL) has continuously developed a high power Nd-glass laser systems for fusion applications over the past 25 years (Dane et al., 1997). One of the laser systems can deliver an average pulse energy of 25 100 J, repetition rates of...
