Abstract

When a laser beam impinges on a coated surface, absorption of the laser beam energy causes physical modifications of the material itself, which strongly depend on the laser irradiance E(W/m²) and/or the radiant exposure H (J/m²). At low values of the irradiance (and/or the radiant exposure) heating effects dominate, and the material undergoes reversible changes of its physical properties. However, when the irradiance (and/or the radiant exposure) exceeds a threshold value, irreversible damage of the material will result. We have measured the irreversible damage thresholds for various coatings and after laser irradiation by using an interferometric technique developed by some of the present authors.¹

© 1982 Optical Society of America