C. M. Correia, J.-P. Véran, O. Guyon, C. Clergeon
Abstract
Non-linear curvature wave-front sensing (nlCWFS) delivers outstanding sensitivity and high dynamic range by lifting the linearity constraint of standard curvature wave-front sensing. This is achieved by taking full advantage of diffraction, which encodes wave-front aberrations into patterns of diffraction-limited interference speckles. Originally nlCWFS has been proposed for extreme AO, but it could also be used when the number of modes to measure is lower.The trade is set by a non-linear wave-front reconstruction which involves computationally intensive non-linear algorithms. One such example is the Gerchberg-Saxton iterative algorithm proposed originally. In this paper we propose an approximation that allows us to use the framework developed for phase-diversity to compute the maximum a-posteriori wave-front estimate. We characterize this reconstructor in terms of accuracy and sensitivity to noise and compare its performance to that of the Gerchberg-Saxton algorithm. Finally, we assess the computational requirements of our reconstructor, and discuss its possible real-time implementation.
Proceedings of the Third AO4ELT Conference
S. Esposito, L. Fini
INAF - Osservatorio Astrofisico di Arcetri
2013 December
