Laser-Induced Damage of a 1064-nm ZnS/MgF(2) Narrow-Band Interference Filter

The laser-induced damage thresholds, absorptances, and damage morphologies of ZnS/MgF(2) interference filters that were designed to allow radiation at wavelengths near 1064 nm to pass through them have been examined. The damage morphologies as well as their laser behaviors suggest that the initial damage is located not at the surface layers but near the interface of the spacer layer where ZnS is sublimed to form many little bubbles. The electric field distribution and the temperature rise in the multilayer was calculated to model this interesting phenomenon. Various explanations for the thermodynamic coupling are presented.