From flagship observatories to small earth-observation satellites, many NASA missions require high performance optical components that are also cost-effective to manufacture and launch. Freeform optical components can reduce a telescope's size and weight (reducing launch costs) but are challenging to test and validate with traditional metrology tools due to their lack of symmetry and large changes in curvature (increasing manufacturing costs). Improved metrology systems for freeform optics have potential to improve performance and reduce manufacturing costs by avoiding prescription-specific null correctors or holograms. Metrology systems for freeform optics require a challenging combination of capabilities: high-resolution (ideally sub-nanometer) measurement of large deviations from a planar surface and steep surface slope. At OptiPro Systems, we have recently developed (in part through NASA SBIR projects) an interferometric probe capable of sub-nanometer metrology of optical surfaces, which is essential for precision optical components such as telescope mirrors. In Phase I, we designed probes capable of measuring large surface sag and steep surface slope, which would allow direct application of these probes to freeform optics. We propose constructing, testing, and calibrating new prototype interferometric probes that will enable cost-effective metrology of freeform optics. These probes have long measurement range and wide acceptance angle while maintaining sub-nanometer performance. Using the results of our Phase I, we have completed a major redesign of the probe optical system. The Phase II project aims to finalize the optical design; construct, align, and calibrate these probes; and deliver a report detailing the prototype probes' performance and their potential use in metrology of high-performance freeform optics. Anticipated
Benefits: Potential NASA applications include metrology of freeform and other optical components for NASA missions, including flagship/decadal missions, small satellites, and everything between. Some specific applications: Origins Space Telescope (OST) and Large UV/Optical/IR Surveyor (LUVOIR), which may use freeform optics. Lynx, Advanced X-ray Imaging Satellite (AXIS), and other X-ray telescopes. Large telescope mirrors, such as those for the Habitable Exoplanet Observatory (HabEx), OST, and LUVOIR, requiring sub-nanometer metrology. The proposed metrology probe would benefit many applications, including: Metrology of high-precision optical components for commercial products Metrology of x-ray and neutron mirrors (Department of Energy) Vibration analysis of mechanical components and machines
