Object wave reconstruction by speckle illumination and phase retrieval

An innovative setup for the speckle-based phase retrieval method is proposed. In the conventional setup, a plane wave illuminates the test object and the transmitted wavefront is incident on a diffuser aperture generating a speckle field. The sampled speckle intensities at axially displaced planes are input into a phase retrieval algorithm based on a wave propagation equation.

In the new setup, the arrangement of the diffuser and the object is reversed. A plane wave incident on the diffuser generates a speckle field which, in turn, is used to illuminate the object. The transmitted wavefront is then directed to the camera sensor. The advantage of the proposed setup is the increased resolution since the limiting aperture is the full area of the sensor.