Phase contrast metrology using digital in-line holography: General models and reconstruction of phase discontinuities

General models are developed to describe in-line digital phase contrast experiments. They link analytically the reconstruction process and the different parameters of the set-up. Reconstructions of phase discontinuities are realized using 2 Dimensional-Fractional Fourier Transforms (2D-FRFT). They give the 3D position and the dimension of the phase object, and the phase shift introduced. Experimental results and simulations are in good concordance. The technique can be used with monochromatic or with large spectrum laser sources.

► General models are developed to describe in-line digital phase contrast experiments. ► Models use generalized Huygens-Fresnel integrals and transfer matrices. ► Models are extended to the femtosecond illumination regime. ► Digital reconstructions are done with the fractional Fourier transformation.