Nonequilibrium Plasma Cleaning of Organic Contaminants on the Surface of Diffraction Gratings

Organic contamination of large-aperture optical components is one of the crucial factors limiting the energy boost of inertial confinement fusion (ICF). Plasma cleaning technology is a safe method of optical components surface treatment and has good application prospects in eliminating superficial organic contaminants. This study conducted nonequilibrium plasma cleaning experiments on diffraction gratings to investigate the upshot of cleaning process parameters on surface cleanliness. Surface morphology and wettability after contamination were measured to evaluate surface cleanliness. The outcomes of water contact angle (WCA) and surface free energy (SFE) indicated that the characteristic of gratings has improved after processing. The experimental results demonstrated that the nonequilibrium plasma cleaning techniques were competent in recovering the surface micromorphology of diffraction gratings. The surface cleanliness was further improved after atmospheric and low-pressure plasma cleaning by parameter optimization of the response surface methodology (RSM). This research provides guiding implications for improving plasma cleaning and parameter optimization in its engineering applications.