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Proceedings Paper

Zernike wavefront sensor modeling development for LOWFS on WFIRST-AFTA
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Paper Abstract

WFIRST-AFTA design makes use of an existing 2.4m telescope for direct imaging of exoplanets. To maintain the high contrast needed for the coronagraph, wavefront error (WFE) of the optical system needs to be continuously sensed and controlled. Low Order Wavefront Sensing (LOWFS) uses the rejected starlight from an immediate focal plane to sense wavefront changes (mostly thermally induced low order WFE) by combining the LOWFS mask (a phase plate located at the small center region with reflective layer) with the starlight rejection masks, i.e. Hybrid Lyot Coronagraph (HLC)’s occulter or Shaped Pupil Coronagraph (SPC)’s field stop. Zernike wavefront sensor (ZWFS) measures phase via the phase-contrast method and is known to be photon noise optimal for measuring low order aberrations. Recently, ZWFS was selected as the baseline LOWFS technology on WFIST/AFTA for its good sensitivity, accuracy, and its easy integration with the starlight rejection mask. In this paper, we review the theory of ZWFS operation, describe the ZWFS algorithm development, and summarize various numerical sensitivity studies on the sensor performance. In the end, the predicted sensor performance on SPC and HLC configurations are presented.

Paper Details

Date Published: 16 September 2015
PDF: 14 pages
Proc. SPIE 9605, Techniques and Instrumentation for Detection of Exoplanets VII, 960528 (16 September 2015); doi: 10.1117/12.2186191
Show Author Affiliations
Xu Wang, Jet Propulsion Lab. (United States)
J. Kent Wallace, Jet Propulsion Lab. (United States)
Fang Shi, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 9605:
Techniques and Instrumentation for Detection of Exoplanets VII
Stuart Shaklan, Editor(s)

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