Fourier optics: imaging with diluted apertures

Abstract

We describe in this communication the principle of imaging with diluted apertures from the theoretical point of view of Fourier optics, for a noiseless experiment using perfect telescopes in space. Two extreme cases are considered, corresponding to dense and sparse arrays. Dense arrays make it possible to obtain a complete spatial frequency coverage; after signal processing, the images are comparable to those obtained with a very large monolithic aperture. Such a perfect frequency coverage cannot be obtained with parse arrays for which the distances between telescopes are very large compared to their size. These arrays can only sample the Fourier plane at point-like individual frequencies, with the drawback of a field limitation. Sparse arrays have however the most promising perspectives for imagery of stars and exoplanets surfaces.