Atmospheric pressure plasma-assisted laser ablation of optical glasses

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This work investigates two approaches for atmospheric pressure plasma-assisted ablation of optical glasses. The first approach involves sequential plasma-assisted ablation, where glasses undergo plasma pre-treatment before laser ablation using a hydrogenous process gas. This pre-treatment modifies the optical properties, particularly the transmission characteristics, through mechanisms such as the formation of suboxide layers, hydrogen implantation into the glass bulk, and surface roughening. These changes enhance the coupling of incoming laser irradiation, resulting in a significant reduction of the laser ablation threshold and improved machining quality, characterized by higher contour accuracy and reduced surface roughness. The second approach, simultaneous plasma-assisted ablation, involves guiding the laser beam coaxially with an argon plasma beam, leveraging plasmaphysical interactions. This method notably increases the ablation rate due to additional energy transfer from the plasma and helps smooth rough optical glass surfaces. The combination of these approaches offers a novel integrated plasma-assisted ablation process, enabling high-quality microstructuring of optical devices.