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Fresnel arrays and their astrophysical applications

2011; Springer Science+Business Media; Volume: 30; Issue: 2-3 Linguagem: Inglês

10.1007/s10686-011-9225-6

1572-9508

L. Koechlin, Jean‐Pierre Rivet, Ana I. Gómez de Castro,

Space exploration and regulation

Astronomy present a new optical concept for high resolution imaging in astronomy: the Fresnel Imagers, as well as some prospects for its application in various fields of astrophysics.Fresnel imagers are based on the initial work by Augustin Fresnel and the binary Soret rings plate concept, dating back to the nineteenth century.Recent work has shown that they are ideally suited for very high performance imaging in space.Fresnel imagers may provide the solution for very large apertures in space.They are able to provide high angular resolution and dynamic range in many wavelength domains.However, they do not carry large heavy mirrors: a thin and light foil replaces the primary.This foil is opaque but a large number of subapertures are cut out into it.This foil design is described in the first papers of this special issue.In short, it is formed by an orthogonal structure of bars superposed to void Soret (Fresnel) rings.The bars mesh holds the circular rings together, while perturbing as little as possible the high image quality.Light is focused by diffraction and forms an image at a distant focus.The chromatism inherent to diffraction focusing is canceled by an opposite diffraction in a small optical element downstream.This setup takes full advantage of space