Optical Metrology of Aspheric and Freeform Mirrors

The NASA Science Missions Directorate seeks technology for cost-effective high-performance advanced space telescopes for astrophysics and Earth science applications. These applications require instruments with large aperture light-weight highly reflecting mirrors and precision optical surfaces to gain a better understanding of how the universe works. The hard and soft X-ray mirrors have stringent surface requirements. If awarded a Phase I our plan would be to combine previous knowledge of OptiPro's UltraSurf metrology system with newly developed software. Our goal would be to create a robust solution for combining the measurement data of the mirrors with corrective machine grinding and polishing process toolpaths. This proposal includes the investigation utilizing non-contact probes on OptiPro's machining platforms to quantify the potential opportunities for in-situ mirror measurements. Understanding these surface irregularities and what in the manufacturing processes causes them is critical for improving the current TRL's. OptiPro Systems will develop a metrology system and software, that would provide feedback for manufacturing these precision mirrors and include final metrology measurement of global form error and mid-spatial content. Comparison of in-situ and off-line metrology will be key for improving the manufacturing processes. We envision that the work performed in Phase I would lead to a software and metrology solution to be built and delivered to NASA if awarded a Phase II. OptiPro's technologically advanced optical manufacturing capabilities along with our support partnership with the University of Rochester Mechanical Engineering Department, gives us a very strong team and a clear path towards solving the difficult challenges for measuring these large complex mirrors and cylindrical shells. Our goal is to provide an innovative and complete manufacturing solution for the companies that are fabricating these optical components for NASA.

UltraSurf and in-situ machine metrology will be key technologies for advancing the state of the art for accurate and cost effective fabrication of many current and future NASA optical components. These applications may include the measurement of forming mandrels used to produce multiple segmented shell mirrors for the International X-Ray Observatory (IXO) and (NXGO). The aspheric and freeform optical surfaces required by LISA and WFIRST will also benefit from the metrology advances made with this endeavor. UltraSurf and in-situ metrology would also be very useful for measuring of the segmented types of telescope systems such as the Advanced Technology Large Aperture Space Telescope (ATLAST). As NASA space exploration requirements evolve so too will the need for better quality optical elements. The continued advancement of UltraSurf and the available probe solutions will be critical in keeping up with these requirements. As OptiPro (a U.S. machine builder) through this SBIR effort develops new metrology solutions there is the added advantage that many companies not just OptiPro, have the opportunity to benefit from a successful project. This has been well proven in our Navy Phase III SBIR commercialization results.

Since 1989 OptiPro has developed and refined conceptual technologies into robust deterministic machines and processes for the optical fabrication industry. Non-NASA commercial applications include the fabrication of flats, spheres, aspheres, and complex conformal shapes such as aerodynamic ogive domes. Commercialization of these technologies has developed into very cost effective solutions. UltraSurf has excellent potential for applications where mid-spatial-frequency and slope surface errors are an issue such as EUV lithography. Another application is for laser amplifiers, such as the Inertial Confinement Fusion National Ignition Facility (NIF) at Lawrence Livermore National Laboratory and the Laboratory for Laser Energetics, at the University of Rochester. For these types of applications, laser damage threshold and irradiance distribution are critical and therefore mid-spatial frequency errors need to be minimized after the polishing stage. UltraSurf advances will be critical for measuring these errors. In addition there are many new military optical systems requiring conformal and freeform shaped optics which also need these advancing metrology capabilities. UltraSurf has also proven invaluable for the non-contact measurement of stainless steel injection mold inserts for military optical visors.

This is early/mid-stage (TRL 5) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.