High-Z Ultrathin Foil Fabrication for Intense Laser Experiments

High-Z metallic foils including rare-earth (RE) elements are required for some experiments implemented on the Laser Megajoule. A specific process based on physical vapor deposition and laser machining was developed to produce high-Z material foils meeting strict specifications. This process allows pure metallic ultrathin foil fabrication from a few hundred nanometers to several microns of thickness of any high-Z materials. In the case of RE metals sensitive to oxidation, thin foils are buried under aluminum protective layers of about a few hundred nanometers. These metallic thin foils are flat, show thickness uniformity over 95%/cm², and have roughness of about 10 nm. The foils are opaque to light, have a density similar to bulk material, present an oxygen content of about 1 at. %, and are stable over months under atmospheric conditions.