Fast Linearized Coronagraph Optimizer (FALCO) IV. Coronagraph design survey for obstructed and segmented apertures

TL;DR

This paper uses the FALCO optimizer to rapidly compare coronagraph designs for obstructed and segmented space telescopes, demonstrating effective diffraction suppression for Earth-like exoplanet detection.

Contribution

It introduces a fast optimization approach for coronagraph design trade-offs in complex telescope apertures, enabling large-scale surveys.

Findings

Deformable mirror apodization can suppress diffraction from support structures.

Designs achieve detection of Earth-sized planets within tens of milliarcseconds.

FALCO enables rapid evaluation of different coronagraph configurations.

Abstract

Coronagraph instruments on future space telescopes will enable the direct detection and characterization of Earth-like exoplanets around Sun-like stars for the first time. The quest for the optimal optical coronagraph designs has made rapid progress in recent years thanks to the Segmented Coronagraph Design and Analysis (SCDA) initiative led by the Exoplanet Exploration Program at NASA's Jet Propulsion Laboratory. As a result, several types of high-performance designs have emerged that make use of dual deformable mirrors to (1) correct for optical aberrations and (2) suppress diffracted starlight from obstructions and discontinuities in the telescope pupil. However, the algorithms used to compute the optimal deformable mirror surface tend to be computationally intensive, prohibiting large scale design surveys. Here, we utilize the Fast Linearized Coronagraph Optimizer (FALCO), a tool that allows for rapid optimization of deformable mirror shapes, to explore trade-offs in coronagraph designs for obstructed and segmented space telescopes. We compare designs for representative shaped pupil Lyot and vortex coronagraphs, two of the most promising concepts for the LUVOIR space mission concept. We analyze the optical performance of each design, including their throughput and ability to passively suppress light from partially resolved stars in the presence of low-order aberrations. Our main result is that deformable mirror based apodization can sufficiently suppress diffraction from support struts and inter-segment gaps whose widths are on the order of $\sim$0.1% of the primary mirror diameter to detect Earth-sized planets within a few tens of milliarcseconds from the star.