Ceramic mirrors are going to become more and more attractive for realizing lightweight optomechanical systems. The C/SiC ceramic described in this article, a joint development of DSS and IABG offers design freedom through a novel straight forward manufacturing process, combined with excellent optomechanical properties. This process not only enables to build ultra lightweight mirrors of very high complexity, but also very large 3d-structures. Mirrors up to 80 cm and structures up to 2.5m have been realized. The paper will summarize the recent progress achieved in producing mirror blanks up to m diameter and beyond. Recent results in new technologies for achieving high performance optical surfaces will be reported.An outlook for future envisaged applications of C/SiC technology, e.g. 2.5 m mirror segments for the next generation of large earth and space based telescopes, is given.
We contend that carbon fiber reinforced silicon carbide material (C/SiC), developed by IABG, represents the state-of-the-art for ultra-lightweight, high precision optomechanical structures that must operate in adverse environments and over wide ranges of temperature. C/SiC employs conventional NC machining/milling equipment to rapidly fabricate near-net shape parts, providing substantial schedule, cost, and risk savings for high precision components. Unlike powder based SiC ceramics, C/SiC does not experience significant shrinkage during processing, nor does it suffer from incomplete densification. By modifying certain process steps, the thermal and mechanical properties of C/SiC are tunable in certain ranges. This paper focuses on recent advances in C/SiC technology and application of this technology to high precision, lightweight applications such as meter-class optics and optical mounts. We also introduce a design for new, high precision mounts based upon standard optical grade C/SiC (formulation A-3) and a custom formulation of C/SiC (D-4) which was engineered for Schafer Corporation by IABG. The A-3 and D-4 formulations have a near-perfect CTh match with silicon, making them the ideal material to athermally support ultra-lightweight silicon optics that will operate in a cryogenic environment
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