Comparison of materials for use in the precision grinding of optical components

Precision grinding of optical components is becoming an accepted practice for rapidly and deterministically fabrication optical surfaces to final or near-final surface finish and figure. In this paper, a comparison of grinding techniques and materials is performed. Flat and spherical surfaces were ground in three different substrate materials: BK7 glass, chemical vapor deposited (CVD) silicon carbide ceramic, and sapphire. Spherical surfaces were used to determine the contouring capacity of the process, and flat surfaces were used for surface finish measurements. The recently developed Precitech Optimum 2800 diamond turning and grinding platform was used to grind surfaces in 40mm diameter substrates sapphire and silicon carbide substrates and 200 mm BK7 glass substrates using diamond grinding wheels. The results of this study compare the surface finish and figure for the three materials.