Nano-Textured Anti-Reflection Microstructures (ARMs) for Enhanced Performance IRFPAs

Infrared imaging has revolutionized the Armys approach to warfare, providing the capability to see day or night through smoke, fog, and dust. Imaging in all battlefield conditions enables 24-hour covert targeting and tracking, threat warning, hostile fire identification; thereby increasing mission capability while providing protection for the troops. For high-resolution imaging in all conditions, the Army utilizes electro-optic/infrared (EO/IR) focal plane arrays that cover the VISIBLE to LWIR spectral range. For suppression of problematic reflections from the high index sensor surfaces, thin film antireflection coatings are employed. The Army has identified that these coatings do not adequately suppress reflections to mission specifications and often have environmental durability issues related to stress and thermal fluctuations. An innovative and rugged and solution to the AR problem is based on surface relief AntiReflective Microstructures (ARMs) imparted directly in the sensor substrate material through a simple plasma deposition, etch, and cleaning process. With no dissimilar materials as a component of the AR treatment, stress and environmental durability issues are eliminated. The optical performance of microstructures has been shown to be far superior to thin film coatings with respect to reflection suppression, transmission bandwidth, and off-axis performance. The combination of large batch processing, short cycle times, and in-situ process controls result in an ARMs manufacturing process that will produce the low unit costs required to equip the warfighter in the field.