Hybrid curvature and modal wavefront sensor

The crosstalk effect considerably limits the capability of holography-based modal wavefront sensing (HMWS) when measuring wavefronts with large aberrations. In this contribution, we introduce a curvature-based measurement technique into HMWS to extend the dynamic range and the sensitivity of HMWS via a compact holographic design. If the input aberrations are large, the dominating aberration modes are first detected via curvature sensing and compensated using a wavefront correcting device, e. g. a membrane mirror. The system then switches to HMWS to obtain better sensitivity and accuracy with reduced aberrations. Different approaches for the reconstruction of the wavefront have been tested and extensive simulations for different aberrations have been analyzed.