OPTICAL APERTURE SYNTHESIS AND WAVE-FRONT SENSING

To apply phase closure with an array of optical telescopes, each apert ure must be phased. This sets an upper limit on the size of each apert ure equal to the coherence area of the wave fronts (if no adaptive opt ics is used). By recording the wave-front on each aperture and by post -processing, it is possible to apply phase closure algorithms with ape rtures sustaining an arbitrary high number of coherence areas, as far as the combination remains coherent. This procedure increases substant ially the signal-to-noise ratio in the visible and stands as a complem ent when adaptive optics only provides a partial correction of wave-fr onts.