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Efficient Detection and Characterization of Exoplanets within the Diffraction Limit: Nulling with a Mode-selective Photonic Lantern

Xin, Yinzi and Jovanovic, Nemanja and Ruane, Garreth and Mawet, Dimitri and Fitzgerald, Michael P. and Echeverri, Daniel and Lin, Jonathan and Leon-Saval, Sergio and Gatkine, Pradip and Kim, Yoo Jung and Norris, Barnaby and Sallum, Steph (2022) Efficient Detection and Characterization of Exoplanets within the Diffraction Limit: Nulling with a Mode-selective Photonic Lantern. Astrophysical Journal, 938 (2). Art. No. 140. ISSN 0004-637X. doi:10.3847/1538-4357/ac9284.

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Coronagraphs allow for faint off-axis exoplanets to be observed, but are limited to angular separations greater than a few beam widths. Accessing closer-in separations would greatly increase the expected number of detectable planets, which scales inversely with the inner working angle. The vortex fiber nuller (VFN) is an instrument concept designed to characterize exoplanets within a single beam width. It requires few optical elements and is compatible with many coronagraph designs as a complementary characterization tool. However, the peak throughput for planet light is limited to about 20%, and the measurement places poor constraints on the planet location and flux ratio. We propose to augment the VFN design by replacing its single-mode fiber with a six-port mode-selective photonic lantern, retaining the original functionality while providing several additional ports that reject starlight but couple planet light. We show that the photonic lantern can also be used as a nuller without a vortex. We present monochromatic simulations characterizing the response of the photonic lantern nuller (PLN) to astrophysical signals and wavefront errors, and show that combining exoplanet flux from the nulled ports significantly increases the overall throughput of the instrument. We show using synthetically generated data that the PLN detects exoplanets more effectively than the VFN. Furthermore, with the PLN, the exoplanet can be partially localized, and its flux ratio constrained. The PLN has the potential to be a powerful characterization tool complementary to traditional coronagraphs in future high-contrast instruments.

Item Type:Article
Related URLs:
URLURL TypeDescription
Xin, Yinzi0000-0002-6171-9081
Jovanovic, Nemanja0000-0001-5213-6207
Ruane, Garreth0000-0003-4769-1665
Mawet, Dimitri0000-0002-8895-4735
Fitzgerald, Michael P.0000-0002-0176-8973
Echeverri, Daniel0000-0002-1583-2040
Lin, Jonathan0000-0001-8542-3317
Leon-Saval, Sergio0000-0002-5606-3874
Gatkine, Pradip0000-0002-1955-2230
Kim, Yoo Jung0000-0003-1392-0845
Norris, Barnaby0000-0002-8352-7515
Sallum, Steph0000-0001-6871-6775
Additional Information:We thank the anonymous reviewer for their careful consideration and feedback. This work is supported in part by the National Science Foundation Graduate Research Fellowship under grant No. 1122374. Additional effort has been supported by the National Science Foundation under grant No. 2109231. This research was carried out in part at the California Institute of Technology and the Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration (NASA).
Group:Astronomy Department
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1122374
Issue or Number:2
Record Number:CaltechAUTHORS:20221031-575177800.19
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117657
Deposited By: Research Services Depository
Deposited On:09 Nov 2022 18:08
Last Modified:11 Nov 2022 17:36

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