Mechanisms of pulsed laser induced damage to optical coatings
Abstract
Laser induced damage in optical components is the limiting factor in the design of high power lasers. This problem is addressed with special emphasis placed on the optical coatings used on the components. A theoretical model is developed assuming basic mechanisms which lead to damage of the coatings. Numerical results are generated and compared with experimental data. The basic procedure applied is that of the solution of inhomogenous field equations representing classical heat and electron diffusion in solids. The technique used is integral transform mathematics. Results are supported by modeling with a numerical finite element program. Findings include several sets of scaling relations which give insight into the relationship of the damage threshold of optical coatings to the material and laser parameters involved. These are plotted against experimental data for support of the assumed processes. These findings include the fact that the rate at which thermal diffusion occurs in optical components is important, and that there is a fundamental difference in the damage process between oxide and fluoride coatings. In addition, basic mechanisms are suggested as the source of damage in these coatings.
 Publication:

Final Report New Mexico Univ
 Pub Date:
 July 1986
 Bibcode:
 1986unm..rept.....L
 Keywords:

 Antireflection Coatings;
 Coatings;
 Laser Damage;
 Laser Materials;
 Optical Materials;
 Pulsed Lasers;
 Thin Films;
 Electrons;
 Finite Element Method;
 Fluorides;
 Integral Transformations;
 Mathematical Models;
 Oxides;
 Rates (Per Time);
 Scaling Laws;
 Thermal Diffusion;
 Lasers and Masers