Pulsed laser-induced damage to thin-film optical coatings - Part I: Experimental

We report a parameteric investigation of the damage threshold and morphology of nine frequently employed dielectric coatings as a function of pulse length (5 and 15 ns), frequency (1.06, 0.53, 0.35, and 0.26 μm), and film thickness. A vidicon camera and computer were used to obtain real-time laser spatial profiles for each testing event. This technique greatly reduced the time required to obtain damage thresholds and enabled a large matrix of data to be obtained. The data and damage morphologies are discussed and several important conclusions are drawn concerning pulsed laser-induced damage to optical materials in thin-film form.