Related papers: A Broadband Scalar Vortex Coronagraph
High performance coronagraphic imaging at small inner working angle requires efficient control of low order aberrations. The absence of accurate pointing control at small separation not only degrades coronagraph starlight rejection but also…
We present an optical design of astronomic spectrograph based on a cascade of volume-phase holographic gratings. The cascade consists of three gratings. Each of them provides moderately high spectral resolution in a narrow range of 83 nm.…
Detection and characterization of exoplanets by direct imaging requires a coronagraph designed to deliver high contrast at small angular separation. To achieve this, an accurate control of low order aberrations, such as pointing and focus…
In this paper, we present the infrared coronagraphic test bench of the University of Li\`ege named VODCA (Vortex Optical Demonstrator for Coronagraphic Applications). The goal of the bench is to assess the performances of the Annular Groove…
A crucial component of the high-contrast instrumental chain in astronomy is the wavefront sensor (WFS). A key property of this component is its sensitivities, which reflect its ability to efficiently use incoming photons to encode the phase…
We present the first observations obtained with the L'-band AGPM vortex coronagraph recently installed on LBTI/LMIRCam. The AGPM (Annular Groove Phase Mask) is a vector vortex coronagraph made from diamond subwavelength gratings. It is…
NASA's Habitable Worlds Observatory (HWO) concept and the 2020 Decadal Survey's recommendation to develop a large space telescope to "detect and characterize Earth-like extrasolar planets" requires new starlight suppression technologies to…
Solar and stellar externally occulted coronagraphs share similar concepts, but are actually very different because of geometric characteristics. Solar occulters were first developed with a simple geometric model of diffraction perpendicular…
We present an algorithm that uses the distribution of photon arrival times to distinguish speckles from incoherent sources, like planets and disks, in high contrast images. Using simulated data, we show that our approach can overcome the…
The second-generation instrument SPHERE, dedicated to high-contrast imaging, will soon be in operation on the European Very Large Telescope. Such an instrument relies on an extreme adaptive optics system coupled with a coronagraph that…
Phase masks coronagraphs can be seen as linear systems that spatially redistribute, in the pupil plane, the energy collected by the telescope. Most of the on-axis light must ideally be rejected outside the aperture to be blocked with a Lyot…
As adaptive optics technology continues to improve, the stellar coronagraph will play an ever increasing role in ground-based high-contrast imaging observations. Though several different image masks exist for the most common type of…
Imaging exoplanetary systems is essential to characterizing exoplanetary systems and to studying planet-disk interactions to understand planet formation. Such imaging in the visible and near-infrared is challenging because these objects are…
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…
One of the science drivers for the extremely large telescope (ELT) is imaging and spectroscopy of exo-solar planets located as close as 20mas to their parent star. The application requires a well thought-out design of the high contrast…
Coronagraphic imaging in combination with moderate to high spectral resolution may prove more effective in both detecting extrasolar planets and characterizing them than a standard coronagraphic imaging approach. We envisage an…
The Roman coronagraph instrument will demonstrate high-contrast imaging technology, enabling the imaging of faint debris disks, the discovery of inner dust belts, and planets. Polarization studies of debris disks provide information on dust…
Several coronagraph designs have been proposed over the last two decades to directly image exoplanets. Among these designs, the vector vortex coronagraphs provide theoretically perfect starlight cancellation along with small inner working…
We present here new experimental results on high contrast imaging of 10^{-7} at 4.5Lambda/D (Lambda = 0.820 microns) by combining a circular focal plane mask (coronagraph) of 2.5Lambda/D diameter and a multi-Gaussian pupil plane mask. Both…
Discovering exoplanets in orbit around distant stars via direct imaging is fundamentally impeded by the combined effect of optical diffraction and photon shot noise under extreme star-planet contrast. Coronagraphs strive to increase the…