Introduction to Multi-Conjugate Adaptive Optics systems

The paper describes the basic concepts underlying the design of Multi-Conjugate Adaptive Optics systems. The paper takes into account mainly three papers. The first paper, published in 1988, is due to J. Beckers and it introduces the currently used multi-conjugation concept and quantifies the increase in FoV achieved applying this concept with respect to the single conjugate adaptive system. The second paper considered is due to M. Tallon and R. Foy. This paper, published in 1990, provides a quantitative method to estimate the 3D map of the atmospheric phase perturbation. This is the needed information to properly control the multi-conjugate system introduced by J. Beckers. Finally a third paper, published in 2000 and due to R. Ragazzoni et al. is considered, where the Layer Oriented scheme is described opening the multi-conjugate adaptive system field to natural guide stars. These three papers stimulated a lot of other contributions from several people and some of them are briefly discussed in the paper. To cite this article: S. Esposito, C. R. Physique 6 (2005).