Phase diversity is a focal plane wavefront sensing technique that allows to retrieve the phase aberration introduced by a camera starting from two images of whatever object, one of which (the diverse image) is intentionally corrupted by a known aberration. We present here the results of a simulation campaign aimed at assessing the validity of this approach for sensing non-common path aberrations (NCPA) in SHARK-NIR, the new-generation high-contrast imager for the Large Binocular Telescope (LBT). The aberrations to be retrieved has been modeled on a realistic error budget of the instrument, while images are generated with an end-to-end Fresnel simulator which makes use of atmospheric phase screens to simulate realistic closed-loop observations. A wide parameter space is explored in order to identify the critical parameters and to estimate the expected level of correction.

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D. Vassallo, J. Farinato, J.-F. Sauvage, T. Fusco, D. Greggio, E. Carolo, V. Viotto, M. Bergomi, L. Marafatto, A. Baruffolo, and M. De Pascale, "Validating the phase diversity approach for sensing NCPA in SHARK-NIR, the second-generation high-contrast imager for the Large Binocular Telescope," Proc. SPIE 10705, Modeling, Systems Engineering, and Project Management for Astronomy VIII, 1070516 (Presented at SPIE Astronomical Telescopes + Instrumentation: June 12, 2018; Published: 10 July 2018); https://doi.org/10.1117/12.2313301.