![(Left) The aperture assumed in these simulations. Furthermore, the stellar radius is assumed to be 0.03 λ/D, and the planet is assumed to be at 1 λ/D in the positive X direction. Middle) The single-moded measurement shown in the pupil plane (top) and focal plane (bottom) obtained by using the highest information mode from the calculation of the SLD, denoted here as SLD Mode 0. Right) The single-moded measurement shown in the pupil and focal planes as calculated using a classical numerical optimization. Pupil plane extents are from -0.5 to 0.5 (with an aperture diameter normalized to 1), while focal plane extents are from -5 λ/D to 5λ/D. Both of these methods are described in Ref. 13, and achieve ηs ≈ 1 × 10−9 , with ηp at 1 λ/D of approximately 19%, and a maximum ηp of 73% at 1.8 λ/D. -- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Optimal-mode-sorting.png?fit=1200%2C673&ssl=1)
[astro-ph.IM] Conventional coronagraph architectures struggle to reach the theoretical limit of exoplanet detection at close working angles. Spatial mode-sorting is capable of reaching the theoretical limit, which previous work has calculated for a completely unresolved star whose signal lies entirely in the fundamental piston mode of the telescope.
More recently, we have calculated optimized nulling modes as a function of the size of the star and planet parameters, with the goal of improving coronagraphic performance at ~l/D working angles given partially resolved stars and complex telescope apertures.
In this work, we further explore the limits of a coronagraph involving the measurement of a single spatial mode, with potential applications for the infrared arm of the Habitable Worlds Observatory.
We present the achievable single-channel 1 l/D planet throughput as a function of the single-channel stellar suppression (for a 0.03 l/D diameter star), and show that the ability to measure a single optimized spatial mode can allow us to reach at least ~80% of the theoretical information limit.
Yinzi Xin, Sebastiaan Haffert, Rico Landman
Comments: 6 pages, 3 figures, proceedings of SPIE Astronomical Telescopes + Instrumentation 2026, 14148-134
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2607.17637 [astro-ph.IM] (or arXiv:2607.17637v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2607.17637
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Submission history
From: Yinzi Xin
[v1] Mon, 20 Jul 2026 07:46:30 UTC (619 KB)
https://arxiv.org/abs/2607.17637
Astrobiology, Astronomy, exoplanet,
