Effect of Pad Elastic Modulus on The Polishing Induced Plastic Subsurface Damages Distribution of Fused Silica Optics

The plastic subsurface damages distribution of fused silica optics polished with different pads are investigated. The elastic interaction model, plastic indentation model and wear relationships are combined together to theoretically characterize the plastic subsurface damages distribution in different polishing processes, which shows consistent results with experiments. It reveals that most of the polishing induced subsurface damages are plastic damages. A few largest polishing particles in the tail end distribution mainly decide the final depth distribution and density of the polishing induced plastic subsurface damages. The larger pad elastic modulus will make the few largest polishing particles bear much larger load and generate larger proportion of observable plastic subsurface damages. Using polishing pad with lower elastic modulus is prominent for restricting the generation of fractures and plastic damages