Accurate threshold curves of laser-induced damage (7-ns single shot at 1.064 microm) are measured in bulk and at the surfaces of optical components such as substrates, thin films, multilayers, and liquids. The shapes and the slopes of the curves are related to the spot size and to the densities of the nanodefects that are responsible for damage. First, these densities are reported for bulk substrates. In surfaces and films the recorded extrinsic and intrinsic threshold curves permit the discrimination of the effects of microdefects and nanodefects. In all cases the density of nanocenters is extracted by means of a phenomenological approach. Then we test liquids and mixtures of liquids with controlled defect densities. The results emphasize the agreement between measurement and prediction and demonstrate the validity of the presence of different kinds of nanocenter as the precursors of laser damage.

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An automatic test apparatus for refined testing of laser damage is presented that permits an in situ analysis of the tested area before, during, and after pulsed irradiation. Spatial and temporal beam profiling are performed in real time and give access to the localized fluence for each shot. Furthermore, an optimization of the initiation of damage detection is undertaken by use of image processing and yields a resolution better than 1 microm. Through several examples, these conditions are demonstrated to be useful for reaching an understanding of the laser-damage process. A complete study is undertaken of different kinds of glass that permits the main influence of test parameters (shot frequency, shot number, beam profile variation, temporal and spatial meshing, ...) on the damage procees to be shown. The study was made for different test procedures (1:1, S:1, R:1) and completed by atomic-force microscope analysis. Evidence indicates that the upgrading of metrology associated with an automatic process offers new opportunities for understanding laser-induced damage mechanisms and for emphasizing specific effects such as damage initiation, damage growth, and conditioning for repetitive shots.