Plasma-induced atom migration manufacturing of fused silica

Abstract

In this study, we report an ultra-precision nonsubtractive surface polishing technique named plasma-induced atom migration manufacturing (PAMM). In PAMM, the molten layer of the fused silica surface can be formed owing to the energy transmitted by inductively coupled plasma (ICP) which has a high gas temperature and radical density. The smoothing of surface is attributed to the rearrangement of surface atoms or clusters driven by surface tension. Unlike conventional subtractive smoothing processes, PAMM removes no material and can achieve damage-free surface with high efficiency and low cost, which makes it a promising technique to obtain large optical components with excellent optical performance and long operation life. The static and scanning smoothing characteristics of PAMM were presented and the surface smoothing mechanism was discussed. By this method, an ultrasmooth surface with Sa roughness of 0.15 nm was achieved. Furthermore, the validity of PAMM of spherical surface polishing and damaged surface recovering of fused silica was experimentally verified.