Silicon Carbide Steering Mirrors for High Energy Laser Applications

SSGPO proposes the demonstration of a cost effective process for producing SiC optics for high thermal load mirror applications. SiC optics provide the combination of high specific stiffness for highly lightweighted mirrors and high thermal stability fordimensional stability and thermal management under extreme thermal loads. The fabrication process utilizes two advanced manufacturing techniques to produce rapid turn around/cost effective optics. SSGPO's slip cast forming process provides near netshaped mirror substrates that require minimal post-machining. In addition, the casting process allows multiple components to be produced using the same tooling. The second technique is computer controlled optical surfacing (CCOS) for achieving highlyaccurate surface figures through a deterministic, computer controlled sub-aperture polishing process.In Phase I a SiC fast steering mirror will be designed for the Airborne Laser Program. SiC provides an excellent solution for this requirement. The high specific stiffness enables the bandwidth of the steering mirror to be increased in comparison to thepresent Si mirror. The high thermal load imposed by the ABL laser demands high thermal conductivity and low coefficient of thermal expansion. The combination of near-net shape casting and CCOS polishing provides the fabrication of a SiC mirror whichmeets these demanding requirements in a cost effective manner.In Phase II, SSGPO will work with a prime contractor to fabricate and test a 12