Imaging with Optical Synthetic Apertures (Mills-Cross Analog)*

Phased antenna arrays have been used for many years in the field of radio astronomy with considerable success. The principles have heretofore not been applied to optical imagery because of the difficulty of properly phasing a lens array at optical frequencies. This paper discusses the principles of radio interferometry and the optical analog of a particular array, the Mills-cross antenna. The experimental realization of the Mills-cross analog is shown for an f/30 system in which the resolution capabilities approach the theoretical limit for this type of aperture. In this experiment, an inverse filter is used to remove the bias information.