Non-interferometric, non-iterative phase retrieval by Green's functions

In this paper a non-interferometric, non-iterative method for phase retrieval by Green's functions is presented. The theory is based on the parabolic wave equation that describes propagation of light in the Fresnel approximation in homogeneous media. Green's first identity will be used to derive an algorithm for phase retrieval considering different boundary conditions. Finally it will be shown that a commonly used solution of the transport-of-intensity equation can be obtained as a special case of the more general Green's function formulation derived here.