ABSTRACT
In the 1970s, when data on the laser-induced damage thresholds of optical materials were being published for the first time, the range of values measured for even high quality materials varied markedly. P. V. Avizonis’ original analysis assumed that the focused laser beam has a Gaussian distribution. An extension of Saito’s method is to make the measurement using a linear array of photodiodes, or similar detectors, and to integrate the energy received at each detector. Avizonis’ single-pulse photographic method is quick and easy to use once the equipment is set up and has the advantage over all the other methods in thatis possible to measure the beam divergence at any azimuthal angle across the beam in a single shot. Photographic methods are therefore useful in showing up irregularities in the beam structure. Repetitive laser irradiation may deteriorate and damage optical surfaces at irradiation levels below those measured for single-shot damage.
