Surface finish and optical quality of CaF2 for UV-lithography applications

CaF2 has received increasing attention as a promising substrate for coatings in the VUV range. Optimization of the optical properties of these optical components requires the study of basic characteristics of the coated and uncoated CaF2 substrates such as surface roughness, optical performance, absorption and scatter losses, and laser induced damage threshold. The investigations reveal the influence of different substrate polishing grades on the quality of the coated components.