Phasing segmented mirrors with a Laser Guide Star

The purpose of this PhD is to assess both theoretically and experimentally the feasibility of measuring the phasing state of a segmented mirror using a Laser Guide Star (LGS). After a review of the state of the art and limitations, the candidate will first study in detail the case of monostatic LGS launch (i.e. without spot elongation), develop and commission an experimental set-up to be incorporated in 2021-2022 to the ESO CANAPY experiment in La Palma using the ESO 50 W LGS. Then the candidate will address the case of side launch (elongated spot) and propose strategies for large segmented telescopes.