A major issue in high power lasers for fusion is laser-induced damage on optics and its evolution in time after a large number of shots. Since damage is often characterized by an initial surface crack, its surface usually increases, following an exponential law.
Surface scratches have been made on silica samples in order to get calibrated fractures. Then, to test different experimental conditions, we made a variety of scratches in terms of length and depth. The samples are then irradiated by a Nd:YAG laser first at 1064 nm (1w) then at 355 nm (3w). They are successively tested with the scratches facing the laser beam or placed with the scratches on the back surface.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.