Abstract New approach to fabricate diamond diffractive optical elements (DOEs) with continuous relief for powerful CO2 lasers is proposed and tested. It involves short-pulse laser microstructuring of a silicon wafer, which further is used as a substrate for polycrystalline diamond growth in a microwave plasma-assisted CVD process. After fine mechanical polishing of the growth side of the diamond film, the silicon substrate is removed via chemical etching. Two different DOEs providing close to 100% diffraction efficiency were fabricated with this technique: cylindrical Fresnel lens with kinoform surface profile and three-beam splitter with continuous microrelief. Optimization of the laser processing conditions has made possible to reduce the final roughness of the structured diamond surface to 200–400 nm depending on the local relief depth (0–7 μm). Both DOEs tested with a CO2 laser have demonstrated high transparency and diffraction efficiency, as well as low radiation scattering of the IR radiation at the surface irregularities.

中文翻译：

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通过在硅模板上复制激光微结构，为强大的 CO2 激光器制造金刚石衍射光学元件

摘要 提出并测试了一种新的方法来制造具有连续浮雕的强大 CO2 激光器的金刚石衍射光学元件 (DOE)。它涉及硅晶片的短脉冲激光微结构化，进一步用作微波等离子体辅助 CVD 工艺中多晶金刚石生长的基材。在对金刚石膜的生长侧进行精细机械抛光后，通过化学蚀刻去除硅衬底。使用这种技术制造了两种不同的 DOE，提供接近 100% 的衍射效率：具有kinoform 表面轮廓的圆柱形菲涅耳透镜和具有连续微浮雕的三分束器。根据局部浮雕深度 (0-7 μm)，激光加工条件的优化可以将结构化金刚石表面的最终粗糙度降低至 200-400 nm。