Nonlinear optimization algorithm for retrieving the full complex pupil function

Techniques for retrieving the phase of an optical field typically depend on assumptions about the amplitude of the field in a desired plane, usually a pupil plane. We describe an approach that makes no such assumptions and is capable of retrieving both the amplitude and phase in the desired plane. Intensity measurements in two or more planes are used by a nonlinear optimization algorithm to retrieve the phase in the measurement planes. The complex field (amplitude and phase) in the desired plane is then computed by simple propagation. We show simulation results and examine the convergence of the algorithm.