Design and Technology of Excimer Lasers

Although the chemical reaction processes responsible for the excitation of excimer lasers seem to offer ideal operational conditions, the technical realization of reliable laser systems for scientific and industrial use is a demanding task. The design of excimer lasers is complicated by several factors. The gas mixtures used in the laser contain the halogens fluorine or chlorine, which are highly corrosive. The laser systems are operated at gas pressures of up to 6 x 105 Pa and can contain relatively large gas volumes, making highstrength mechanical construction necessary. Voltages of more than 40 kV are used for the excitation, requiring efficient high-dielectric-strength insulators. These factors severely limit the choice of materials that can be employed for the construction of the laser. The design of lasers to be employed in the industrial environment is more demanding than that for scientific and laboratory use. In contrast to scientific applications, where performance is the most important question, in industry issues such as low operating cost, longterm reliability, ease of operation and safety are of overriding importance. As a consequence, designs prefer simple and proven technology, being cautious of possibly more efficient, but more complex and therefore higher risk approaches.