TY - JOUR
T1 - Laboratory demonstration of spatial linear dark field control for imaging extrasolar planets in reflected light
AU - Currie, Thayne
AU - Pluzhnik, Eugene
AU - Guyon, Olivier
AU - Belikov, Ruslan
AU - Miller, Kelsey
AU - Bos, Steven
AU - Males, Jared
AU - Sirbu, Dan
AU - Bond, Charlotte
AU - Frazin, Richard
AU - Groff, Tyler
AU - Kern, Brian
AU - Lozi, Julien
AU - Mazin, Benjamin A.
AU - Nemati, Bijan
AU - Norris, Barnaby
AU - Subedi, Hari
AU - Will, Scott
N1 - Funding Information:
We thank the NASA Strategic Astrophysics Technology (SAT) Program for their generous support of this project (grant # 80NSSC19K0121); T.C. is supported by a NASA Senior Postdoctoral Fellowship. ExoTAC members provided extremely helpful guidance for defining our Milestone #1 requirements, which are reported in this publication. Mamadou N’Diaye, John Krist, and the anonymous referee provided helpful comments.
Publisher Copyright:
© 2020. The Astronomical Society of the Pacific. All rights reserved. Printed in the U.S.A.
PY - 2020/10
Y1 - 2020/10
N2 - Imaging planets in reflected light, a key focus of future NASA missions and extremely large telescopes, requires advanced wavefront control to maintain a deep, temporally correlated null of stellar halo—i.e., a dark hole (DH)— at just several diffraction beam widths. Using the Ames Coronagraph Experiment testbed, we present the first laboratory tests of Spatial Linear Dark Field Control (LDFC) approaching raw contrasts (∼5 × 10−7 ) and separations (1.5–5.2λ/D) needed to image Jovian planets around Sun-like stars with space-borne coronagraphs like WFIRST-CGI and image exo-Earths around low-mass stars with future ground-based 30 m class telescopes. In four separate experiments and for a range of different perturbations, LDFC largely restores (to within a factor of 1.2–1.7) and maintains a DH whose contrast is degraded by phase errors by an order of magnitude. Our implementation of classical speckle nulling requires a factor of 2–5 more iterations and 20–50 deformable mirror (DM) commands to reach contrasts obtained by spatial LDFC. Our results provide a promising path forward to maintaining DHs without relying on DM probing and in the low-flux regime, which may improve the duty cycle of high-contrast imaging instruments, increase the temporal correlation of speckles, and thus enhance our ability to image true solar system analogues in the next two decades.
AB - Imaging planets in reflected light, a key focus of future NASA missions and extremely large telescopes, requires advanced wavefront control to maintain a deep, temporally correlated null of stellar halo—i.e., a dark hole (DH)— at just several diffraction beam widths. Using the Ames Coronagraph Experiment testbed, we present the first laboratory tests of Spatial Linear Dark Field Control (LDFC) approaching raw contrasts (∼5 × 10−7 ) and separations (1.5–5.2λ/D) needed to image Jovian planets around Sun-like stars with space-borne coronagraphs like WFIRST-CGI and image exo-Earths around low-mass stars with future ground-based 30 m class telescopes. In four separate experiments and for a range of different perturbations, LDFC largely restores (to within a factor of 1.2–1.7) and maintains a DH whose contrast is degraded by phase errors by an order of magnitude. Our implementation of classical speckle nulling requires a factor of 2–5 more iterations and 20–50 deformable mirror (DM) commands to reach contrasts obtained by spatial LDFC. Our results provide a promising path forward to maintaining DHs without relying on DM probing and in the low-flux regime, which may improve the duty cycle of high-contrast imaging instruments, increase the temporal correlation of speckles, and thus enhance our ability to image true solar system analogues in the next two decades.
KW - Astronomical instrumentation
KW - Exoplanet detection methods
KW - Exoplanets
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U2 - 10.1088/1538-3873/aba9ad
DO - 10.1088/1538-3873/aba9ad
M3 - Article
AN - SCOPUS:85091720488
VL - 132
SP - 1
EP - 11
JO - Publications of the Astronomical Society of the Pacific
JF - Publications of the Astronomical Society of the Pacific
SN - 0004-6280
IS - 1016
M1 - 104502
ER -