Scientific Background

Adaptive Optics (AO) is a technique that aims at compensating rapidly-varying optical aberrations to restore the ultimate angular resolution limit of an optical system. It uses a combination of wave-front sensors, to sense and analyze the optical aberrations, and deformable mirrors to compensate for them. For astronomical telescopes, AO allows one to overcome the natural ''seeing'' frontier: the blurring of images imposed by atmospheric turbulence that limits the angular resolution of ground-based telescope to that achievable by a 10 to 50cm telescope, an order of magnitude below the diffraction limit of large 8-m class telescopes which are the current standard.

Over the past 20-years, AO observations have made possible some of the major discoveries in astronomy with, among others, detailed study of the massive black hole at the center of our Galaxy, detailed images of the surface of solar systems planets or precise morphology and dynamics of very distant galaxies. AO for astronomy has revolutionized observations with ground-based telescopes by providing the highest achievable image quality to the community and it is now inconceivable to consider building a large optical telescope without AO.

We are today at the beginning of a new era for AO, with the deployment of a revolutionary generation of AO systems called Wide Field AO (WFAO). By using multiple Laser Guide Stars (LGS), WFAO increases both the field of the AO corrected images and the fraction of the sky that can benefit from such correction by an order of magnitude. Therefore, whereas the first AO systems were well suited for observations of bright and relatively small objects, the new generation of WFAO is opening the path for a multitude of new science cases.