REPAIR & TROUBLESHOOTING - USAF Removing Optical Coatings

Final technical report from the Air Force Weapons Laboratory (AFWL) examining chemical methods for removing thin-film optical coatings. This document presents an efficient alternative to traditional polishing for reclaiming valuable optical substrates. The primary advantage of the chemical approach lies in its selectivity: specific layers within an optical coating design can be removed while preserving underlying layers intact, something virtually impossible with mechanical polishing. The report covers removal of metallic and dielectric coatings including gold, silver, chromium, thorium, fluoride, and zinc selenide applied to various optical substrates such as molybdenum, titanium, zirconium-molybdenum alloys, germanium, and silicon. The study details chemical corrosion properties, suitable reagents, and optimal conditions for achieving effective removal while minimizing substrate damage and toxic material production. The document establishes baseline data for commonly used infrared optical coatings and indicates future research expansion to additional substrates and coatings for near-infrared, visible, and ultraviolet wavelengths.