Using thin films as debris shields for laser micro-machining and high energy laser target interactions

Target debris has long been a problem when using low f-number optics for laser micro-machining applications or high energy laser target interactions. A debris shield can be used to protect the final focusing optics from damage. Therefore we have started to investigate the optical properties of various thin films such as Nitrocellulose, Mylar, and Polyimide with respect to their application as laser debris shields. Studies on optical and spectral transmission quality, absorption, stress induced birefringence, and damage threshold (short and long pulse) have been performed. For high energy, large aperture lasers, scalability up to 43 cm diameter has been demonstrated. Such large debris shields have been successfully used at Sandia's 100 TW laser system.