Observations of circumstellar environments that look for the direct signal of exoplanets and
the scattered light from disks have significant instrumental implications. In the past 15 years …

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has been
developed from concept to on-sky application in many high-contrast imaging systems on 8 m …

Fourier-based wavefront sensors, such as the Pyramid Wavefront Sensor (PWFS), are the
current preference for high contrast imaging due to their high sensitivity. However, these …

Context. High-contrast imaging (HCI) observations of exoplanets can be limited by the island
effect (IE). The IE occurs when the main wavefront sensor (WFS) cannot measure sharp …

Context. Direct detection of exoplanets around nearby stars requires advanced adaptive
optics (AO) systems. High-order systems are needed to reach a high Strehl ratio (SR) in near …

Direct imaging instruments have the spatial resolution to resolve exoplanets from their host
star. This enables direct characterization of the exoplanets atmosphere, but most direct …

Context. One of the key limitations of the direct imaging of exoplanets at small angular
separations are quasi-static speckles that originate from evolving non-common path …

SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for more than 5 years,
demonstrating a high level of performance. SPHERE has produced outstanding results …

The Optimal Optical CoronagraphWorkshop at the Lorentz Center in September 2017 in
Leiden, the Netherlands gathered a diverse group of 30 researchers working on exoplanet …

Resolution and sensitivity of the wavefront sensor (WFS) are key requirements for eXtreme
Adaptive Optics (XAO) applications. We present a new class of WFSs, the Bi-Orthogonal …