Zonal error removal for large aspheric with multi-mode combined manufacture technique

In order to satisfy the requirements of large mirrors for the fabrication precision, the removal of zonal errors for a large aspheric is analyzed with the Multi-mode Combined Manufacture (MCM) technique in this study. The MCM technology discussed is based on the traditional fabrication theory, in which the multi-mode machining combined the multiple polishing of the laps is used to finish the optical component to control the low and middle frequency errors effectively of the optical surface. The principle of JP-01 polishing manipulator which is an important part of the MCM technology is presented, and the working mode of MCM is analyzed in detail. Finally, the MCM technology is used to deal with the zonal error of an aspheric with the aperture of 1 230 mm. The experimental results show that the MCM technology can control the low and middle frequency errors of the optical surface effectively, constrain the surface error and improve the polishing efficiency observably. At present, the precision of a large on-axis mirror with the aperture of 1-2 m has reached 30 nm(RMS). These results prove that the MCM can be one of the important technologies for the development of the large mirror manufacture.