Manufacturing meter-scale aspheric optics

Deterministic subaperture finishing technologies, such as Magnetorheological Finishing (MRF (R)) are becoming the industry standard for finishing high precision optics with complex shapes, such as aspheres. However, astronomical or very large optics were beyond the scale of existing capabilities and relied on traditional, artisan-based methods of manufacture. It is not uncommon for these critical parts to spend a year or more in production. Recent developments from QED Technologies (R) have expanded MRF technology to enable the manufacture of meter-scale aspheric optics. QED, in conjunction with the Steward Observatory Mirror Laboratory (SOML) at the University of Arizona, demonstrated the fabrication of an 840 nun diameter convex asphere with 1.3 mm of aspheric departure from a best-fit sphere. Long-trace profilometry scans were initially performed at SOML to characterize the surface. A first figure correction polishing iteration was conducted at QED Technologies in Rochester, NY on a meter-class MRF machine (Q22-950F). The correction improved the surface to within the capture range of a full aperture interferometric test performed at the Mirror Lab. A final polishing iteration at QED improved the surface to meet the optic specifications.