With CO2-laser radiation glass material can be melted and ablated. These processes are used to reduce the surface roughness of optics by melting (laser polishing) as well as to reduce form errors by ablation (high precision laser ablation). The manufacturing time in particular for polishing and form correction of nonspherical optics can be reduced significantly. Current results of laser polishing and high precision laser ablation are presented. With laser polishing, the surface roughness of fused silica, borosilicate glass (BK7) and flint glass (S-TIH6) can be reduced significantly. But, the achieved waviness is not yet sufficient for imaging optics. Hence, high precision laser ablation is used to ablate material locally in a vertical dimension down to 5 nm.
"Laser polishing of glass", Proc. SPIE 9633, Optifab 2015, 963303 (11 October 2015); doi: 10.1117/12.2200972; https://doi.org/10.1117/12.2200972