High Performance Optical Coatings for Advanced Seeker Systems

Future advanced seeker systems for endo- and exo-atmospheric applications will utilize not only the passive and invisible infrared signature of ballistic threats but also LADAR based ranging imaging and discrimination information for improvedidentification, discrimination, and tracking. The present optical instruments for seekers utilize beryllium (Be) optics for lightweight IR performance. The integration of ranging and imaging LADAR and combined passive IR and visible imaging will requiretwo critical changes to the optics in these applications: (1) the use of alternative optical materials to enable visible quality optical performance, and (2) high energy, low stress induced, low absorptive laser coatings with very high reflectance at theLADAR wavelength and additionally acceptable performance for IR and visible wave bands. The high reflectance coatings also need to be survivable to advanced nuclear environment, as well as be very durable to maintain performance over long term storage ina silo.SSGPO is currently working with Raytheon to develop a lightweight silicon carbide (SiC) based advanced seeker optical architecture, which incorporates LADAR, and visible and IR imaging channels with visible image quality. A SiC demonstration mirror isbeing fabricated as a pathfinder for this effort with bolt together capability. In this Phase I, SSGPO will develop a very low absorption reflective coating design and fabrication approach with optimized performance for the HEL line and visible and IRbands. Phase II will leverage the ongoing SiC mirror demonstration program with Raytheon to produce and test the developed coating on the ADLT SiC primary mirror. Applications for bolt together SiC passive/active systems with performance in the visibleand IR include next generation seeker systems critical to missile defense (e.g., ADLT, CEKV, MKV), laser-based defense like the space-based laser (SBL), air-borne last (ABL), and advanced tactical systems using LADAR. Private sector applications includeearth resource mapping, law enforcement, disaster relief, optical lithography, and other applications in which the improved situational awareness provided by combined active passive sensors is of value.