Phase retrieval microscope based on photon image detection

The accuracy and sensitivity of the phase retrieval from a Fraunhofer diffraction pattern greatly depend on the dynamic range of the measured Fraunhofer diffraction pattern. In this study, a photon-imaging detector was adopted to detect higher order diffraction spots of a very weak phase grating. The phase retrieval was accomplished fairly well experimentally from the Fraunhofer diffraction intensity distribution data including up to the third-order diffraction spots to which the iterative Fourier transform algorithms were applied. The object phase distribution was retrieved with satisfactory accuracy and sensitivity. A newly introduced procedure for measuring the entire diffraction pattern with single photon-imaging detector is also described.