Volume 635, March 2020
|Number of page(s)||9|
|Published online||09 March 2020|
The Single-mode Complex Amplitude Refinement (SCAR) coronagraph
II. Lab verification, and toward the characterization of Proxima b
Leiden Observatory, Leiden University,
PO Box 9513, Niels Bohrweg 2,
2 Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, NC 27695, USA
Accepted: 28 November 2017
We present the monochromatic lab verification of the newly developed SCAR coronagraph that combines a phase plate (PP) in the pupil with a microlens-fed single-mode fiber array in the focal plane. The two SCAR designs that have been measured, create respectively a 360 degree and 180 degree dark region from 0.8–2.4λ∕D around the star. The 360 SCAR has been designed for a clear aperture and the 180 SCAR has been designed for a realistic aperture with central obscuration and spiders. The 360 SCAR creates a measured stellar null of 2–3 × 10−4, and the 180 SCAR reaches a null of 1 × 10−4. Their monochromatic contrast is maintained within a range of ±0.16λ∕D peak-to-valley tip-tilt, which shows the robustness against tip-tilt errors. The small inner working angle and tip-tilt stability makes the SCAR coronagraph a very promising technique for an upgrade of current high-contrast instruments to characterize and detect exoplanets in the solar neighborhood.
Key words: instrumentation: high angular resolution / instrumentation: spectrographs / techniques: high angular resolution / techniques: imaging spectroscopy
© ESO 2020
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