Final Report Summary - VORTEX (Taking extrasolar planet imaging to a new level with vector vortex coronagraphy) The VORTEX project aimed to bridge the gap between short-period exoplanets, discovered by radial velocity and photometric transit techniques, and long-period exoplanets, discovered with current high-contrast imaging instruments, by enabling high contrast imaging of planetary systems at small angular separations. To reach this goal, the project relied on the design, manufacturing, testing, installation, and exploitation of vortex phase masks for stellar coronagraphy on state-of-the-art, 10-m class telescopes assisted by adaptive optics. These phase masks are based on the use of sub-wavelength gratings, etched onto synthetic diamond substrates. The project particularly focused on wavelengths that have not been properly addressed by coronagraphs so far, including the thermal infrared regime (3-13μm), where warm planets radiate most of their thermal emission. Within this project, we designed and manufactured a new generation of thermal infrared (MWIR) vortex phase masks reaching peak starlight rejection rates higher than 1000:1. These rejection rates have been measured on our ERC-funded infrared optical test bench dedicated to coronagraphy. Several of our vortex phase masks are now installed in world-leading observatories, such as the Very Large Telescope, the Keck Observatory, and the Large Binocular Telescope. They have led to new discoveries in the field of exoplanet science, including the detection of a couple of young exoplanets probably still in the process of being formed within the protoplanetary disks around young stars. We have also developed innovative image processing algorithms to analyze high-contrast images, which are now offered in open source to the whole community through the Vortex Image Processing (VIP) python package. Based upon that body of work, and on the tools developed within this project, we are now in the process of specifying and designing new vortex phase masks for the future Extremely Large Telescope, with the final goal to enable the detection of low-mass planets in the habitable zone of nearby stars.