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Co-phasing primary mirror segments of an optical space telescope using a long stroke Zernike WFS

Jackson, Kate and Wallace, J. K. and Pellegrino, Sergio (2016) Co-phasing primary mirror segments of an optical space telescope using a long stroke Zernike WFS. In: Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave. Proceedings of SPIE. Vol.1. No.9904. Society of Photo-Optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 99046D. ISBN 9781510601871. http://resolver.caltech.edu/CaltechAUTHORS:20160929-095806840

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Abstract

Static Zernike phase-contrast plates have been used extensively in microscopy for half a century and, more recently, in optical telescopes for wavefront sensing. A dynamic Zernike wavefront sensor (WFS) with four phase shifts, for reducing error due to spurious light and eliminating other asynchronous noise, has been proposed for use in adaptive optics. Here, we propose adapting this method for co-phasing the primary mirror of a segmented space telescope. In order to extend the dynamic range of the WFS, which has a maximum range of +/ − λ/2, a phase- contrast plate with multiple steps, both positive and negative, has been developed such that errors as large as +/ − 10λ can be sensed. The manufacturing tolerances have been incorporated into simulations, which demonstrate that performance impacts are minimal. We show that the addition of this small optical plate along with a high precision linear translation stage at the prime focus of a telescope and pupil viewing capability can provide extremely accurate segment phasing with a simple white-light fringe fitting algorithm and a closed-loop controller. The original focal-plane geometry of a centro-symmetric phase shifting element is replaced with a much less constrained shape, such as a slot. Also, a dedicated pupil imager is not strictly required; an existing pupil sampler such as a Shack-Hartmann (SH) WFS can be used just as effectively, allowing simultaneous detection of wavefront errors using both intensity and spot positions on the SH-WFS. This could lead to an efficient synergy between Zernike and SH-WFS, enabling segment phasing in conjunction with high-dynamic range sensing.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1117/12.2249638DOIArticle
http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2542100PublisherArticle
ORCID:
AuthorORCID
Pellegrino, Sergio0000-0001-9373-3278
Additional Information:© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE). This work was funded in part by the Spontaneous Research and Technology Development fund at the Jet Propulsion Laboratory. This work was partially carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Group:GALCIT
Funders:
Funding AgencyGrant Number
JPL Research and Technology Development FundUNSPECIFIED
NASA/JPL/CaltechUNSPECIFIED
Record Number:CaltechAUTHORS:20160929-095806840
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160929-095806840
Official Citation:Kate Jackson ; J. K. Wallace and Sergio Pellegrino " Co-phasing primary mirror segments of an optical space telescope using a long stroke Zernike WFS ", Proc. SPIE 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, 99046D (July 29, 2016); doi:10.1117/12.2231736; http://dx.doi.org/10.1117/12.2231736
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70657
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:29 Sep 2016 18:19
Last Modified:05 Jan 2017 00:04

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