Phase retrieval in speckle interferometry: a one-step approach

The paper shows how, in speckle interferometry, the phase information can be retrieved from a single intensity pattern provided that the speckle field captured from the object at the reference conditions is fully resolved in its components of mean intensity, modulation and phase. The “one-step” approach proposed can be applied to the study of transient phenomena if a phase stepping technique can be used to resolve the speckle pattern at the reference conditions. The performance of the procedure has been evaluated and compared with that of the conventional four-step procedure by numerically simulating the diffraction process which occurs in a generic speckle interferometer. Experimental results are reported for a shearing interferometer.