Enhancing Determinism in Atmosphere Plasma Nano-Scale Figuring through Calibration Incorporating Temperature Effects

Abstract Fused silica optical components have extensive applications in various optical fields, and there is an urgent demand for their high-efficiency and non-damaging manufacturing. Atmosphere plasma, as a non-contact and stress-free machining tool, shows great potential for the highly-efficient and damage-free fabrication of optical components. Nevertheless, the plasma heat significantly affects the volume removal rate (VRR), thereby resulting in a lack of determinism when compared to other physical or mechanical-based figuring processes such as ion beam figuring and magnetorheological finishing. In this study, sacrificial substrates have been used to balance the net heat flux on the entire workpiece surface. The global thermal effect, the dwell site thermal effect, and the thermal effect caused by pre-processing during atmosphere plasma figuring were investigated, and the VRR calibration through plane-etching was proposed. A fused silica workpiece (80 mm × 80 mm), with an initial surface form of 156.8 nm (PV) and 33.46 nm (RMS), was processed, and the residual error after figuring was reduced to 36.7 nm (PV) and 1.97 nm (RMS), demonstrating the capability of nano-scale figuring at full aperture using atmosphere plasma.