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15 March 2016 Low-order wavefront sensing and control for WFIRST-AFTA coronagraph
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To maintain the required Wide-Field Infrared Survey Telescope (WFIRST) coronagraph performance in a realistic space environment, a low-order wavefront sensing and control (LOWFS/C) subsystem is necessary. The LOWFS/C uses the rejected stellar light from the coronagraph to sense and suppress the telescope pointing errors as well as low-order wavefront errors (WFEs) due to changes in thermal loading of the telescope and the rest of the observatory. We will present a conceptual design of a LOWFS/C subsystem for the WFIRST-AFTA coronagraph. This LOWFS/C uses a Zernike phase contrast wavefront sensor (ZWFS) with a phase shifting disk combined with the stellar light rejecting occulting masks, a key concept to minimize the noncommon path error. We will present our analysis of the sensor performance and evaluate the performance of the line-of-sight jitter suppression loop, as well as the low-order WFE correction loop with a deformable mirror on the coronagraph. We will also report the LOWFS/C testbed design and the preliminary in-air test results, which show a very promising performance of the ZWFS.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE) 2329-4124/2016/$25.00 © 2016 SPIE
Fang Shi, Kunjithapatham Balasubramanian, Randall Hein, Raymond Lam, Douglas Moore, James Moore, Keith Patterson, Ilya Poberezhskiy, Joel Shields, Erkin Sidick, Hong Tang, Tuan Truong, J. Kent Wallace, Xu Wang, and Daniel Wilson "Low-order wavefront sensing and control for WFIRST-AFTA coronagraph," Journal of Astronomical Telescopes, Instruments, and Systems 2(1), 011021 (15 March 2016).
Published: 15 March 2016


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