Laser damage of optics in high power manufacturing applications. The road from single-shot to billion-shot performance

This paper reviews damage induced by pulsed excimer lasers. Most previous damage studies have addressed the "time-zero" performance limits of optical materials, i.e., virgin samples exposed to one or a small number of laser pulses. In this "single-shot" damage regime, coatings are almost always the weakest link in the optical system. Considerable progress has been made in identifying optimum coating materials and material combinations for particular wavelengths, and in exploring effects of undercoats and overcoats, non-quarter-wave designs, laser pre-conditioning, and alternate polishing and deposition methods on the measured damage threshold. However, adequate single-shot damage resistance is a necessary but not sufficient condition for many practical applications.<
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