Monitoring and diagnosis of the inductively coupled atmospheric pressure plasma jet for deterministic optical processing

Inductively coupled atmospheric pressure plasma processing (IC-APPP) is a promising figuring technique for the optical processing of silicon-based optics. However, its processing efficiency and accuracy rely on the stability of the characteristics of inductively coupled plasma (ICP) jet, which is determined by the jet working parameters. Currently, the jet working parameters have been empirically determined by substantial processing experiments, which is tedious and costly. Therefore, in this paper, a real-time monitoring and diagnostic system for quantitatively measuring and analyzing the jet characteristics is proposed to provide a basis for the choice of optimal working parameters. Firstly, the distributions of temperature and diatomic C2 within ICP jet were obtained, with which some diagnostic indices on the morphology, rigidity and excitation degree of ICP jet were proposed. Then, jet monitoring and diagnostic experiments were conducted to determine the optimal working parameters for generating the ICP jet with high rigidity and excitation degree. Finally, processing experiments under the determined optimal working parameters showed that the stability and repeatability of the removal function were well validated. It demonstrates that the proposed monitoring and diagnostic system is effective for rapid evaluation of ICP sources to determine the optimal working parameters for generating stable ICP jet. © 2020 Elsevier GmbH