The goal is to develop design software for optical coatings that includes accurate simulations of the physics behind laser-induced damage of these coatings. Special emphasis is on coatings for femtosecond-class lasers exhibiting high peak power as well as high average power. The proposed project is a combination of modeling, design, fabrication and test of novel mirrors for ultrashort laser pulses. The main damage limitation of dielectric multi-stack coatings is the local high field enhancements in layers with materials of relatively low threshold. The software to be developed shall steer these enhancements away from zones sensitive to electric field damage. In Phase I, we will develop multi-stack systems with predefined reflection behavior that have reduced field enhancements. This additional criterion will be implemented into the existing software. In addition, we will explore the use of materials with tailored band-gap. At the end of Phase I we envision a proto-type reflector with improved damage threshold for 1-on-1 illumination. In Phase II, we will add design parameters and algorithms to address dispersion and material incubation. Laser mirrors and coatings with enhanced laser-induced damage threshold will benefit large laser systems as they are used in several laboratories of the DoE (Sandia, Livermore, Berkeley, and others). Also, these coatings are interesting for military grade high-power lasers.
