Exoplanet detection techniques for direct imaging dark zone maintenance datasets

With the commencement of the development of the Habitable Worlds Observatory, it is imperative that the community has an understanding of (1) the stability requirements for the observatory to inform the design and (2) the gains expected from post-processing to inform observing scenarios and science yield estimates. We demonstrate that a previously developed, photon-efficient dark zone maintenance (DZM) algorithm that corrects quasi-static wavefront error drifts using only science images is compatible with traditional post-processing techniques. Further, we augment the DZM algorithm to estimate the coherent and incoherent light separately and introduce three novel post-processing techniques that leverage the concurrent estimation of coherent and incoherent light. With the DZM algorithm implemented on the High-contrast imager for Complex Aperture Telescopes testbed at the Space Telescope Science Institute, artificial drifts are injected as a random walk on a set of deformable mirrors and are corrected with DZM. We present an injected fake planet recovered in post-processing using a variety of techniques, such as angular differential imaging (ADI), and three additional techniques: incoherent accumulated imaging, software-based coherent differential imaging, and coherent reference differential imaging. All post-processing techniques can recover an injected planet at the same contrast level as the dark zone background contrast (∼8×10−8), and the ADI technique is shown to recover a 4×10−8 planet in a 8×10−8 dark zone. For a space-based observatory, this would mean that, if the instrument can reach a contrast level, we can maintain it and recover a planet that is undetectable in a single frame.