Institute when accepted: University of Hawai’i at Manoa

Metrology: Characterizing Optical Quality on CVC SiC
Project Site: Trex Enterprises
Mentor: Dennis Douglas

Project Abstract:

Glass materials are typically used for high quality optical mirror applications. These materials have a proven track record for exceptional surface finish and generally maintain low Coefficient of Thermal Expansion (CTE) properties, the capability to expand minimally when heated. For most applications glass optics are desired due to cost and manufacturing considerations. However, novel advanced materials are required for high performance space flight optics, reactionless fast steering mirror systems, and high-energy laser applications. Chemical Vapor Composite Silicon Carbide (CVC SiC) materials are in demand for these specific applications. CVC SiC dissipates heat quickly, is lightweight, maintains low CTE, and possesses high stiffness. The CVC SiC’s greatest strength, its high stiffness, is also its greatest weakness when it is polished because it takes comparatively more time and effort to oppose it. There are current polished CVC SiC samples available by which metrology will be used to determine which polishing method is best for these materials. Thorough understanding of optical surface quality parameters is obtained and applied to procurement of lab hardware, which includes an Interferometer Alignment Mount designed with SolidWorks, suitable for measuring final polished CVC SiC optics. Due to the complexity of the polishing process, full in-house metrology capability is highly desired to verify vendor polishing results.