DETERMINATION OF FIELD CORRELATIONS FROM SPECTRAL MEASUREMENTS WITH APPLICATION TO SYNTHETIC APERTURE IMAGING

By making use of some new results in optical coherence theory we show that spectral analysis, rather than fringe visibility measurements, can be used to determine correlation properties of the field. A principle is also formulated, according to which, in many interferometric measurements a trade-off can be made between the length of the baseline and the frequency at which measurements are made. This principle is a rigorous generalization of the so-called space-frequency equivalence theorem for two antenna detection systems, and it applies to radiation from a broader class of sources than previously considered.