Abstract In this paper, a novel absolute measurement method based on multisurface interference is proposed for a 600 mm aperture interferometer. Compared to existing 3-flat testing methods, which generally require two transmission flats and one reflection flat, our method does not require the replacement of the transmission flat with another flat and rotation of the reflection flat about the z-axis of the 600 mm aperture interferometer. Only by rotating an auxiliary parallel flat about the z-axis can we realize the in situ absolute measurement of the reference flat surface error of the interferometer without losing the medium-frequency error. The principle of absolute measurement based on the proposed novel method is discussed. The various sources of measurement error are analyzed, including the number of rotations, the rotation angle error and the pixel misalignment error of the coordinate axis. Based on these analysis results, an auxiliary rotating device for a large aperture flat is designed. Repeatability experiments were carried out on the 600 mm aperture interferometer produced by Zygo. The experimental results show that the RMS value of the repeatability precision is less than 2 nm.

中文翻译：

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600 mm 孔径干涉仪的原位绝对表面测量

摘要 本文针对600 mm孔径干涉仪提出了一种新的基于多面干涉的绝对测量方法。与通常需要两个透射平面和一个反射平面的现有 3-平面测试方法相比，我们的方法不需要用另一个平面替换透射平面以及绕 600 毫米孔径的 z 轴旋转反射平面干涉仪。只有绕z轴旋转一个辅助平行平面，才能在不损失中频误差的情况下，实现干涉仪参考平面误差的原位绝对测量。讨论了基于所提出的新方法的绝对测量原理。分析了测量误差的各种来源，包括转数、坐标轴的旋转角度误差和像素错位误差。基于这些分析结果，设计了一种用于大口径平板的辅助旋转装置。重复性实验在 Zygo 生产的 600 mm 孔径干涉仪上进行。实验结果表明，重复性精度的RMS值小于2 nm。