The design and analysis of a novel low power atmospheric plasma jet torch for optical fabrication

Over the past few years, atmospheric Inductively Coupled Plasma (ICP) has aroused extensive attention in optical fabrication field since its chemical etching-based processing mode does not mechanically damage work-pieces. However, commercial Fassel-type torch are commonly employed in processing, and the high temperature plasma jet generated by commercial Fassel-type torch will cause thermal damage to optical elements. In this paper, an ICP jet torch is developed for optical fabrication, capable of maintaining plasma jet under a low power of 156 W. By reducing the minimum maintenance power of plasma jet, the processing temperature is down-regulated to 112 °C. To explain the low maintenance power principle in this research, the effect of radial confinement and axial pushing-off on the plasma are analyzed by simulation and experiment processes. Moreover, the effect of these two phenomena on the maintenance power is analyzed experimentally. Subsequently, the experiments are performed to verify the processing temperature, removal efficiency and removal stability of the torch. As revealed from the experimental results, the proposed torch exhibits the stability of footprint up to 97.5%.