Laser induced damage threshold and incubation effects of high-power laser system optics

We present a laser induced damage threshold (LIDT) measurement technique where a mm-diameter non-Gaussian laser beam is used. This allows both a large number of measurements points and a large range of fluence to be sampled with a single measure. The method is used in-situ, inside the laser radiation–matter interaction vacuum vessel used for high power experiments with a 100 TW-class laser system. With our 2.5-Hz repetition rate laser system, the well-known incubation effect is observed where the laser damage threshold on the optics decreases with increasing number of laser shots. The incubation effect is studied with 22-fs laser pulses at a laser 2.5-Hz nominal repetition rate with several optics like dielectric mirrors and gold compression gratings irradiated by up to 9 $\times$ 10$^3$ laser shots.