Aluminium alloy Al6061 is one of the most popular materials for the fabrication of reflective optics. To reveal the influence of material defects in Al6061 on the diffraction effect of diamond turned optics, simulations are performed on a well-established surface topography model. The results indicate that for the defects with similar size parameters in the x- and y-axis direction, e.g. grain boundary, hard inclusion protrusion and void, they are responsible for the diffracted light spots on the whole receiving screen. The scratch on the machined surface mainly affects the diffracted light spots in the horizontal direction; and its influencing pattern is similar to the turning mark. The influence of oxide film on the diffracted light distribution is rather limited due to its uniform property and small thickness on the ambient environment. The simulation and experiment results indicate that the diffraction efficiency of the specular light obviously decreases with the increase of the defect size in the work material matrix.

铝合金Al6061是用于制造反射光学器件的最受欢迎的材料之一。为了揭示Al6061中的材料缺陷对金刚石车削光学元件的衍射效应的影响，对一个完善的表面形貌模型进行了仿真。结果表明，对于在x-和y中具有相似尺寸参数的缺陷轴方向（例如晶界，硬质夹杂物凸起和空隙），它们负责整个接收屏幕上的衍射光斑。加工表面上的划痕主要影响水平方向上的衍射光斑；其影响方式与转折点相似。氧化膜对衍射光分布的影响相当有限，这是由于其均匀的特性和对周围环境的小厚度。仿真和实验结果表明，镜面光的衍射效率随着工作材料基体中缺陷尺寸的增加而明显降低。