The Significance of Image Reversal in the Detection of Hidden Diffractors by Interferometry

The use of coherence measurements to detect diffracting structures masked by noise is investigated theoretically. The overall parity of the image reversals embodied in a two-beam interferometric experimental arrangement is shown to be of crucial significance in interpreting the resulting degree of coherence measurements. Phase curvature at source is also shown to have a discernible effect on the far-zone intensity and coherence. These results are in excellent agreement with recent interferometric experiments.