Phase resolving microscopy by multi-plane diffraction detection.

An easily applicable quantitative phase-contrast microscopy is presented. A bright-field microscope with a coherent illumination is used. Only a series of diffraction images is taken in different distances from the sample. For reconstruction, a conjugate gradient technique as a new variant of phase retrieval technique is developed. The technique is experimentally investigated in detail. A phase accuracy up to 0.07 rad or a height accuracy of 13 nm in transmission for a binary test sample is reached, respectively.