Ion beam finishing techniques of aluminium mirrors have a high potential to meet the increasing demands on applications of high-performance mirror devices for visible and ultraviolet spectral range. Reactively driven ion beam machining using oxygen and nitrogen gases enables the direct figure error correction up to 1 μm machining depth while preserving the initial roughness. However, the periodic turning mark structures, which result from preliminary device shaping by single-point diamond turning, often limit the applicability of mirror surfaces in the short-periodic spectral range. Ion beam planarization with the aid of a sacrificial layer is a promising process route for surface smoothing, resulting in successfully reduction of the turning mark structures. A combination with direct surface smoothing to perform a subsequent improvement of the microroughness is presented with a special focus on roughness evolution, chemical composition, and optical surface properties. As a result, an ion beam based process route is suggested, which allows almost to recover the reflective properties and an increased long-term stability of smoothed aluminium surfaces.

中文翻译：

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铝镜面表面校正后的光学性能的改善

铝镜的离子束抛光技术具有很高的潜力，可以满足对可见光和紫外光谱范围的高性能镜设备的日益增长的需求。使用氧气和氮气进行反应性驱动的离子束加工，可以在不影响初始粗糙度的情况下，对高达1μm的加工深度进行直接图形误差校正。然而，由于通过单点金刚石车削对设备进行初步成形而形成的周期性车削标记结构，经常会限制镜面在短周期光谱范围内的适用性。借助于牺牲层的离子束平面化是用于表面平滑的有前途的工艺路线，从而成功减少了转向标记的结构。提出了与直接表面​​平滑相结合以随后改善微粗糙度的方法，其中特别关注粗糙度的演变，化学成分和光学表面性能。结果，提出了基于离子束的工艺路线，该工艺路线几乎可以恢复反射特性并增加了光滑铝表面的长期稳定性。