The results of antireflection thin film systems for signle crystal CaF2 and silicon windows for application at DF laser wavelengths have been present in this paper. The method designing multilayer AR cating structure has been anlyzed, and ZnS/YbF3 combination. The theoretical performances evaluated for various coating. The deposition process has CaF2 and silicon windows obtained. The damage threshold is more than 4.3kW/cm2 at continue wave DF laser wavelength region for AR coated CaF2 windows.