Description: Increasing the optical surface finishing precision and reducing surface roughness will greatly benefit astronomy telescope and other optical systems. Conventional optical finishing only delivers about 1/10 lambda surface flatness and is hard to handle arbitrary surface shape. To finish optical surface with low cost to an ultra high precision and to reach the capability of generating arbitrary surface shape such as the aspherical surfaces or special patterns, in this proposal, we propose the development of an innovative computer-controlled optical surface finishing system. We suggest using chemical reactive removal as the tool to remove the material on the optical surface, controlled by computer with a deterministic removal algorithm. In phase I, a prototype system with ultra high precision finishing capability, ~ 1/100 lambda (632.8nm) for surface figure and ~1/1000 lambda for RMS will be demonstrated. A 5~10 times improvement in surface roughness is expected over the current technique as the chemical removal is at the atomic or molecular level, rather than by particle bombardment on optical surface. The lower surface roughness will obviously reduce the scattering lose for the short wavelength range. In Phase II, we will extend the work to non-flat surfaces, ie, arbitrary shaped surfaces, and to other glasses and materials of interest to NASA.

Benefits: The proposed system will be a general optical surface finishing system. It will bring the optical fabrication to a new era to cost-effectively manufacture optics with ultra high precision, arbitrary shape and ultra high surface smoothness.

The proposed technique will provide ultra high precision and low surface roughness optics fabrication with reasonable cost, and be able to apply it to arbitrary surface shapes. This will greatly benefit NASA astronomy telescope optical parts fabrication.