Freeform optics allow decreased size and increased flexibility in optical design. However, mid-spatial Frequency (MSF) errors, a common side effect of freeform optic fabrication, can significantly disrupt UV optic performance. Although many techniques have been studied to mitigate MSF errors, elimination often relies on artisan technique. This proposal outlines a feasibility study for the VR HERMES (VIBE Robotic High End Responsive MSF Elimination System). A SiC with silicon cladding, or silicon, freeform optic (diameter =< 0.25 m) will be generated and polished through the techniques derived at Optimax via years of SBIR and commercial work. After polishing, MSF errors will be characterized through metrology such as computer generated holograms and deflectometry, and the errors will be mitigated by artisans. The smoothing process will be completed while the artisans guide collaborative robots. With this procedure, data will be collected regarding the artisan's technique (i.e., a "Process Map"). Through the use of state-of-the-art metrology, Optimax will attempt to capture artisan techniques via machine learning algorithms, and compare that to mapped MSF error data. Optimax will use an iterative approach to create algorithms that can then predict, given an error map, what techniques an artisan would apply to to optic to correct the MSF errors (i.e., a "Predicted Map"). The "Predicted Map" will then be compared to the next "Process Map" and deficiencies identified and used to refine the algorithm. Future work will address creating tool paths directly from metrology data from the "Process Map" algorithms generated in Phase I.
NASA's goals hinge on improved optics with reduced payload size and weight. Freeform optic performance at reduced cost, especially for SiC or Si clad SiC substrates (with its desirable thermal and stiffness characteristics), interests NASA. The proposed technology is germane to UV and other projects such as exo-planet imaging systems, LUVOIR Ultraviolet Multi-Object Spectograph, the Origins Space Telescope, Terrestrial Ecology, Thermal IMager for Europa Reconnaissance and Science, Soft X-Ray telescopes, and Cube/Nano-cube optical payloads.
Cost-effective mid-spatial frequency error reduction can be applied to numerous Optimax freeform markets. Freeform optics can decrease system size improve quality for existing commercial applications such as beam shaping, corrector plates, conformal windows, heads-up displays, compact imaging systems, augmented and virtual reality systems, and reflective, non-imaging illumination components.