Title: Computer-aided alignment in null testing of large aspheric mirrors

Authors: Yang Lin Peng; Yi Fan Dai; Xu Hui Xie; Shan Yong Chen; Gui Lin Wang

Addresses: College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073, China ' College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073, China ' College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073, China ' College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073, China ' College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073, China

Abstract: During the null testing of aspheric mirrors, the error induced by misalignment of the null compensator or the mirror will couple with the surface figure and consequently give incorrect information for deterministic figuring. A mathematical alignment model of null testing is established, and the computer-aided alignment software is developed to determine the misalignment in this paper. Based on the analysis of aberration compensation with different alignment parameters, numerical simulations show that high accuracy alignment of null testing can be achieved by adjusting only five degrees of freedom of the null compensator, on condition that a planar interferometer is used and the amount of misalignment is small.

Keywords: large aspheric mirrors; null testing; computer-aided alignment; aberration compensation; null compensator misalignment; mathematical modelling; numerical simulation.

DOI: 10.1504/IJNM.2013.055147

International Journal of Nanomanufacturing, 2013 Vol.9 No.2, pp.194 - 200

Received: 13 Sep 2012
Accepted: 16 Jan 2013
Published online: 31 Mar 2014 *

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