The fabrication of atomically smooth metal films on supporting oxides is a quite demanding task, since most physical vapor deposition methods used on metals do not work properly on oxide substrates. Here, we report an alternative procedure, based on performing laser polishing of a fused silica substrate before depositing the metallic thin film. This reduces the RMS surface roughness of fused silica by ca. 33%, and increases the maximum grain size of the metallic film from 200 nm to 1200 nm. The method has been applied to a fused silica parabolic lens, which has been coated with a graphene-terminated Ru thin film. The reduction of surface roughness caused by laser polishing leads to the formation of ultrasmooth Ru thin films. Crystallinity and subnanometer roughness of the metal coating are demonstrated by the observation of He diffraction from a macroscopically curved surface.

中文翻译：

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激光抛光弯曲熔融石英上的超光滑金属薄膜

在支撑氧化物上制造原子级光滑的金属薄膜是一项非常艰巨的任务，因为大多数用于金属的物理气相沉积方法在氧化物基材上都不能正常工作。在这里，我们报告了一种替代程序，基于在沉积金属薄膜之前对熔融石英基板进行激光抛光。这将熔融石英的 RMS 表面粗糙度降低了约 33%，并将金属膜的最大晶粒尺寸从 200 nm 增加到 1200 nm。该方法已应用于熔融石英抛物面透镜，该透镜已涂有石墨烯封端的 Ru 薄膜。由激光抛光引起的表面粗糙度降低导致形成超光滑的 Ru 薄膜。