Optical surfacing of spherical reaction-burned silicon carbide(RB-SiC) mirror

Optical surfacing and testing process of 250mm spherical reaction-burned silicon carbide(RB-SiC) mirror are mentioned. The machine, tools, abrasives, technology and testing method used in the grinding and polishing are introduced. Some issues frequently occurred in the optical surfacing and testing process are mentioned. Some testing results of surface figure and surface roughness are given. It's showed that the surface figure (RMS, root mean square) is 0.037 wavelength(λ=632.8nm) and surface roughness (RMS) is 1.92nm (measure area 603.6ⅹ448.4μm ). And the photograph of the mirror is showed.