Impact of Cnsup2/sup profile on tomographic reconstruction performance: application to E-ELT wide field AO systems

摘要

New techniques of Adaptive Optics (AO), generically called Wide Field AO, have been developed in the frame of the design study for new instruments for Extremely Large Telescopes (ELI). Concepts such as Multi-Conjugate AO are based on a tomographic reconstruction of the turbulent volume followed by a projection onto DM(s) in order to ensure a good correction in a large Field of View. These systems require a 3D phase reconstruction and a statistical representation of the turbulent volume through the knowledge of the Cnsup2/sup profile, which has a strong impact on performance.We focus our study on the analysis of the impact of the structure and the parameters, which define the Cnsup2/sup profile, on the performance of a given tomographic system for an ELI. In this article, we perform simulation to emphasize the terms which are directly linked to the knowledge of the true input Cnsup2/sup profile, which simulates the input turbulent perturbations, and to the Cnsup2/sup profile which is used as a model in the reconstruction process. We determine and discuss the level of the accuracy needed on the Cnsup2/sup profile to limit the tomographic error term and to ensure a good performance. We show that a good sampling of the input turbulence is required to ensure performance of the system.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.