Guesalaga, ANeichel, BenoitBoccas, Maximed'Orgeville, CelineRigaut, FrancoisGuzman, DAnguita, Jaime2015-12-13July 1-6 29780819491480http://hdl.handle.net/1885/82884The vast majority of large telescopes are now equipped with Adaptive Optics (AO) systems, and many use lasers to create artificial stars (laser guide stars, LGS). Despite the significant advances in the use of LGS for AO, some problems persist during theAuthor/s retain copyrightKeywords: Active elements; Adaptive optics systems; Beam transfer optics; Branch points; Convergence speed; Deformable mirrors; Dynamic aberrations; Large telescopes; Laser guide star; Laser power; Laser systems; Nonlinear problems; Phase retrieval; Phase retrieval Adaptive optics; Deformable mirrors; Laser systems; Phase retrieval201210.1117/12.9249082016-02-24