LASER ABLATION PROCESSING OF SOLID SURFACES IMMERSED IN WATER

摘要

Hole profiles and etching rate of graphite, aluminum, nickel, molybdenum, and tungsten targets irradiated by pulsed laser in water have been examined, and compared with those processed in air. The under-water irradiation gives smoother surfaces of the hole, in comparison with those irradiated in air, except for graphite. The results were basically explained by the debris back-deposition in air atmosphere while no re-deposition in water. In addition to this mechanism, strong plume expansion back to the melted target gives protrusion at the periphery of the hole. The melting point of the target materials seems to be an important parameter.