Digital in-line holography for wavefront sensing

In this paper, we use digital in-line holography (DIH) for wavefront sensing. The method is based on recording in-line digital holograms that are formed by the illumination of a dot array grid (DAG) with an aberrated wavefront and comparing them with a reference wavefront taken by an unaberrated illumination. For each sub-aperture of the DAG, the local slope of the aberrated wavefront displaces the position of the reconstructed spot, and, similar to a Shack-Hartmann wavefront sensor, the wavefront is reconstructed by performing an integration over the wave-slopes. The method is validated by simulation and experiment, and the error sources are investigated. The present method is easy-to-implement and inexpensive, yet, provides an adjustable dynamic range without a need to hardware changes. It has the potential to serve as a bench-top device.