Aperture synthesis in optics

The possibilities are discussed of realizing the principles of aperture synthesis in optics. We denote by aperture synthesis the construction of the equivalent of an optical system with a continuous aperture that consists of a set of elements of smaller aperture, and which permits one to get the same resolution as is attained with the larger system with the continuous aperture. The following approaches are treated: design of composite mirrors of telescopes with automatic alignment of the elements, use of partially filled apertures with subsequent image processing, temporal aperture synthesis, and aperture synthesis with coherent illumination. Data are given that characterize the possibilities and prospectives of the cited aperture synthesis methods. A brief treatment is given of the essence of Gabor's information paradox, which consists in the idea that an $N$-element thin, annular aperture can synthesize an image that contains approximately $N^2$ almost independent elements. We show that the principle of aperture synthesis is perhaps realized in certain living organisms. The promise is noted of using aperture synthesis is perhaps realized in certain living organisms. The promise is noted of using aperture synthesis for optical observations from outer space.