Rapid Damage-Free Shaping of Lightweight SiC Using Reactive Atom Plasma (RAP) Processing

The proposed effort seeks to determine the feasibility of dramatically reducing the manufacturing cost and cycle time of lightweight silicon carbide mirrors by substituting a novel reactive atom plasma (RAP) process for traditional hard tool grinding and lapping. The RAP process employs an inductively coupled plasma torch with common gaseous fluorine compounds to produce a spatially controlled material removal profile. The plasma is scanned over the surface of the material to be shaped under the control of special algorithms to produce the desired optical form. The RAP process exhibits high volumetric material removal rates on SiC and other optical materials. The avoidance of surface and subsurface damage by the use of this non-contact RAP process is expected to significantly reduce the time and cost of optical finishing. RAP-shaped substrates will be polished by several candidate technologies to establish optimum finishing strategies.