  Future large space telescopes will be equipped with adaptive optics (AO) to
overcome wavefront aberrations and achieve high contrast for imaging faint
astronomical objects, such as earth-like exoplanets and debris disks. In
contrast to AO that is widely used in ground telescopes, space-based AO systems
will use focal plane wavefront sensing to measure the wavefront aberrations.
Focal plane wavefront sensing is a class of techniques that reconstruct the
light field based on multiple focal plane images distorted by deformable mirror
(DM) probing perturbations. In this paper, we report an efficient focal plane
wavefront sensing approach for space-based AO which optimizes the DM probing
perturbation and thus also the integration time for each image. Simulation of
the AO system equipped with a vortex coronagraph has demonstrated that our new
approach enables efficient information acquisition and significantly reduces
the time needed for achieving high contrast in space.
