Iterative method to retrieve the propagated wavefront using a Shack–Hartmann sensor

Abstract

We present an iterative procedure to retrieve the wavefront using a Shack–Hartmann sensor. Traditionally, a uniform array of microlens is used as a domain to reconstruct the wavefront under test; however, this properly works if the wavefront differs slightly from a plane. But generally in optical tests, astronomy, and ophthalmology the wavefronts under test can have appreciable deviations with respect to a plane wavefront. The proposed method considers the reconstruction of the wavefront deformations with respect to a known reference wavefront. At each iteration, the wavefront deformation is used to find a reference wavefront closer to the wavefront under test and a domain closer to the actual domain. When the values of the wavefront deformations are small enough, we can take the reference as the wavefront under test. In addition, we simulate the centroid positions of the spot pattern used to retrieve the wavefront under test using the proposed method. We compare our results with those obtained by three other different approaching methods described in the literature (Modal, Trapezoidal Rule, and Southwell). For the simulations used in this work, our method retrieves wavefronts closer to the real wavefront than the other methods. Also, we apply the proposed method to an experimental case to reconstruct the wavefront under test using a Shack–Hartmann sensor.