Revisiting the Borde-Traub focal plane wavefront estimation technique for exoplanet direct imaging
Direct imaging of exoplanets relies on complex wavefront sensing and control architectures. In addition to fast adaptive optics systems, most of the future high-contrast imaging instruments will soon be equipped with focal plane wavefront sensing algorithms. These techniques use the science detector...
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Main Authors | , , , , , , , , , , |
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Format | Journal Article |
Language | English |
Published |
26.08.2024
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Subjects | |
Online Access | Get full text |
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Summary: | Direct imaging of exoplanets relies on complex wavefront sensing and control
architectures. In addition to fast adaptive optics systems, most of the future
high-contrast imaging instruments will soon be equipped with focal plane
wavefront sensing algorithms. These techniques use the science detector to
estimate the static and quasi-static aberrations induced by optical
manufacturing defects and system thermal variations. Pair-wise probing (PWP)
has been the most widely used, especially for space-based application and will
be tested at contrast levels of ~1e-9 on-sky along with the future coronagraph
instrument onboarding the Roman Space Telescope. This algorithm leans on phase
diversities applied on the deformable mirror that are recorded in pairs. A
minimum of two pairs of probes are required per bandwidth. An additional
unprobed image is also recorded to verify the convergence rate of the
correction. Before PWP, Borde & Traub proposed a similar algorithm that takes
advantage of the unprobed image in the estimation process to get rid of the
pair diversity requirement. In this work, we theoretically show that this
latter technique should be more efficient than PWP when the convergence time is
not limited by photon noise. We then present its performance and practical
limitations on coronagraphic testbeds at JPL and exhibit a first on-sky control
of non-common path aberrations with such method on VLT/SPHERE. |
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DOI: | 10.48550/arxiv.2408.14286 |