Radiation-Hard, High Performance AR Treatment For Star Tracker Optics and Sensors

Conventional multi-layer thin film anti-reflection (AR) coatings are complex and exhibit short lifetimes when operating in space due to damage caused by thermal variations and radiation exposure. As a result there is an urgent need for a more durable AR treatment to suppress reflections of visible to near infrared light from the optics and imaging sensors contained in the Star Tracker instruments planned for the STSS program. An innovative type of high performance AR treatment for Star Tracker cameras is proposed that promises superior stray light suppression and increased lifetime in high radiation environments. Based on surface relief microstructures fabricated directly into the sensor window and imaging optic materials, the AR treatment completely eliminates the limitations due to stress, thermal mismatch, adhesion, radiation damage, complexity, narrow-band performance, polarization splitting, and cost associated with conventional multi-layer thin-film AR coatings. The proposed Phase I project will adapt the designs and methods developed in another ongoing MDA SBIR, a program that has demonstrated a radiation-resistant micro-structured AR treatment for HgCdTe infrared FPAs, to demonstrate an improved AR treatment for silicon-based FPAs operating on visible to NIR light. In addition, Star Tracker sensor manufacturers will be engaged and plans will be developed for integrating the improved AR treatment fabrication process into the chip manufacturing process in a Phase II effort.