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Wave-front reconstruction for the non-linear curvature wave-front sensor

C. M. Correia, J.-P. Véran, O. Guyon, C. Clergeon

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

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia