Holographic sparse-aperture telescopes for space

摘要

In order to achieve ultra-large (>20m) effective apertures for space-based telescopes, new techniques will have to be developed to overcome issues of increased launch mass and volume. Research conducted in the past has shown it possible to correct for thousands of waves of surface and geometrical wavefront error using inexpensive image holograms of aberrated primary elements. We now show that this same technique can also be used to simultaneously phase separate primary apertures together. Experimental results presented here demonstrate the phasing and correction of both monolithic membrane primaries and glass flats to diffraction limited performance. In the latter case, the lack of curvature of the mirrors is simply treated as an aberration like any other. The ultimate goal of this project is to conceive a simple correction scheme which will permit space-based imaging interferometers with effective apertures of up to 100m. Although operating over narrow bandwidths, such telescopes may well be suited to lidar, optical communications or high-resolution imaging not requiring multi-spectral detection.