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DIRECTED ENERGY PROFESSIONAL SOCIETY

Abstract: 25-Systems-028

UNCLASSIFIED, PUBLIC RELEASE

Additively Manufactured, Reaction Bonded Silicon Carbide Fast Steering Mirrors (FSM) for Directed Energy Weapon Systems

Silicon Carbide (SiC) is an optimal material for fast steering mirrors in directed energy applications due to its exceptional combination of high specific stiffness, thermal stability and ability to be lightweighted. These properties enable SiC mirrors to maintain precise optical performance even under the dynamic and thermal stress encountered in high energy laser systems.

Adaptive Optics Associates – Xinetics (AOX) has developed an Additively Manufactured Reaction Bonded Silicon Carbide (CeraprintTM SiC). CeraprintTM SiC has been approved for National Security Space Class A missions and has space flight heritage. AOX’s current additive manufacturing capability allows for the printing of mirrors up to 18” in diameter using several available production ready and proven printers.

Typically, to achieve an optical surface finish of less than 10Ǻ rms with reaction bonded silicon carbide, pre-clad polishing is required to bring the surface to within a few microns of the final desired surface figure. This is followed by depositing a thin surface cladding of silicon or SiC (15 to 25µm) and finally a post clad polish to the required surface finish and figure. This is due in large part to the relative difference in hardness of the silicon and silicon carbide phases in the microstructure. Using internal research and development funding, AOX has been working with ZYGO Corporation to develop an approach to bare polish (i.e. no cladding) CeraprintTM Silicon Carbide to a surface finish of less than 10Ǻ rms. This approach will eliminate the need for pre and post clad polishing thereby significantly reducing cost and lead time to produce fast steering mirrors for directed energy applications. The combination of AOX’s Additive Manufacturing and Bare Polishing is expected to reduce the lead time for production of Fast Steering Mirrors ready for coating to 4 to 6 months versus the current typical industry lead times of 9 to 12 months.

The following solution briefing will describe an effort to demonstrate the advantages of a bare polished, additively manufactured silicon carbide solution to produce a Fast-Steering Mirror.
The combination of CeraprintTM SiC material properties, the ability to additively manufacture unique shapes and geometries with the polishing expertise of ZYGO, makes AOX distinctly qualified to help improve the current state of the art for Directed Energy FSM performance.

UNCLASSIFIED, PUBLIC RELEASE