Subsurface damages of fused silica developed during deterministic small tool polishing

The subsurface damages (SSD) of fused silica developed during deterministic small tool polishing are experimentally investigated in this study. A leather pad (i.e., poromeric) is validated to be nearly SSD-free and superior to pitch and polyurethane. Rough abrasives are found to obviously increase SSD depth, and a leather pad can efficiently suppress the adverse effect of rough abrasives. The SSD depth induced by pitch and polyurethane pads (with rough abrasive) ranges from 0.77 to 1.49 mu m (similar to 1/7-1/5 of abrasive size). High pressure, low velocity and slurry concentration can slightly increase SSD depth. Material removal rate of leather pad is also validated to be comparable with polyurethane and much higher than pitch tool; surface roughness polished by leather pad is Ra = 1.13nm, which is close to that of pitch but much better than polyurethane. (C)2014 Optical Society of America