为实现地基拼接式大口径望远镜主镜整体面形连续性,提出了一种新方法,对拼接子镜的相互位置误差进行高精度检测,并进行相关校正,从而使望远镜取得或接近于其衍射极限的光学成像质量。拼接子镜间需要进行校正的位置误差包括子镜间的倾斜误差和垂向平移误差,其中子镜之间的垂向平移误差需要被校正到100 nm以下,相当于入射光波长的几分之一。为实现此目标,在基于迈克耳孙干涉原理的基础上设计出一套相位误差检测系统,应用He-Ne激光与白光作为其光源系统,对拼接主镜子镜间相位误差进行高精度检测,同时解决了垂向平移误差的λ/2相位模糊性问题。系统的不确定度为8～10 nm,检测范围为45～60 μm。对系统的设计进行了分析,并仿真出基于该检测系统的理论干涉图形,得出理想的检测结果。

For a large aperture ground-based telescope with segmented primary mirrors, in order to guarantee the continuity of the figure of the total mirrors, a new interferometric detection method was put forward to detect the phase errors between the segmented mirrors, and correct the misaligned segments correspondingly. This method could make the telescope achieve optical image with diffraction limit. The segment misalignment errors between the segments include tip/tilt error and piston error, the segment piston error between the individual segments must be reduced to less than 100 nm. We have considered an interferometric piston error measurement system based on a Michelson interferometer layout for accomplishing such object. The innovation introduced in the optical design of the interferometer is the simultaneous use of both monochromatic and white-light source that allowing the system to measure the piston error with an uncertainty of 8～10 nm in the range of 45～60 μm. Simultaneously a detailed description about the optical system layout and the theoretic interferograms was gotten.