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Proceedings Paper

Measurement of non-common path static aberrations in an interferometric camera by phase diversity
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Paper Abstract

LINC-NIRVANA (LN) is a near-infrared image-plane beam combiner with advanced, multi-conjugated adaptive optics for the Large Binocular Telescope. Non-common path aberrations (NCPAs) between the near-infrared science camera and the wave-front sensor (WFS) are unseen by the WFS and therefore are not corrected in closed loop. This would prevent LN from achieving its ultimate performance. We use a modified phase diversity technique to measure the internal optical static aberrations and hence the NCPAs. Phase diversity is a methodology for estimating wave-front aberrations by solving an unconstrained optimization problem from multiple images whose pupil phases differ from one another by a known amount. We conduct computer simulations of the reconstruction of aberrations of an optical system with the phase diversity method. In the reconstruction, we fit the wave-front to Zernike polynomials to reduce the number of variables. The limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm is very well suited to phase diversity (PD) due to its good performance in solving large scale optimization problems. The main constraint for the implementation of PD for LN is that we cannot add extra components to the internal interferometric camera imaging system to obtain infocus and defocus images. In this paper, we introduce a new method, namely shifting the focal plane source, not the detector, to overcome this constraint. Some experiments were done to test and verify this method and the results are presented and discussed. The study shows that the method is very flexible and the paper gives practical guidelines for the application of phase diversity methods to characterize adaptive optics systems.

Paper Details

Date Published: 15 October 2012
PDF: 8 pages
Proc. SPIE 8417, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 841726 (15 October 2012); doi: 10.1117/12.974523
Show Author Affiliations
Zhaojun Yan, Max-Planck-Institut für Astronomie (Germany)
Institute of Optics and Electronics (China)
Graduate Univ. of Chinese Academy of Sciences (China)
Thomas M. Herbst, Max-Planck-Institut für Astronomie (Germany)
Pengqian Yang, Max-Planck-Institut für Astronomie (Germany)
Graduate Univ. of Chinese Academy of Sciences (China)
Peter Bizenberger, Max-Planck-Institut für Astronomie (Germany)
Xianyu Zhang, Max-Planck-Institut für Astronomie (Germany)
Institute of Optics and Electronics (China)
Graduate Univ. of Chinese Academy of Sciences (China)
Albert R. Conrad, Max-Planck-Institut für Astronomie (Germany)
Thomas Bertram, Max-Planck-Institut für Astronomie (Germany)
Martin Kuerster, Max-Planck-Institut für Astronomie (Germany)
Hans-Walter Rix, Max-Planck-Institut für Astronomie (Germany)
Xinyang Li, Institute of Optics and Electronics (China)
Changhui Rao, Institute of Optics and Electronics (China)


Published in SPIE Proceedings Vol. 8417:
6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; Libin Xiang; Sandy To, Editor(s)

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