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Proceedings Paper

Precision optical edges for a starshade external occulter
Author(s): John Steeves; Stefan Martin; David Webb; Douglas Lisman; Stuart Shaklan
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Paper Abstract

The use of a starshade is one technique to perform high contrast imaging with space-based telescopes. The primary function of a starshade is to suppress light from a target star in order to image its orbiting planets. In order to provide the proper apodization function the edges of the starshade must follow a precise in-plane profile. However of equal importance is the issue of light from our own sun scattering off of the edges and entering the telescope. A method to alleviate this problem is to make the edges extremely sharp (< 1 μm terminal radius) such that the area available for scattering is minimized. The combination of these two requirements, along with the need to integrate the edges into a 30-40 m dia. deployable structure, present a number of significant engineering challenges. Substrate etching techniques are used to obtain both the intended profile as well as the edge sharpness. Current efforts implement an isotropic etching process on thin metal substrates. This paper discusses the progress towards producing a sharp optical edge at the coupon level. Samples have been characterized using scanning electron microscopy as well as a custom testbed to assess their scattered-light performance.

Paper Details

Date Published: 22 July 2016
PDF: 11 pages
Proc. SPIE 9912, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, 99122O (22 July 2016); doi: 10.1117/12.2233409
Show Author Affiliations
John Steeves, Jet Propulsion Lab. (United States)
Stefan Martin, Jet Propulsion Lab. (United States)
David Webb, Jet Propulsion Lab. (United States)
Douglas Lisman, Jet Propulsion Lab. (United States)
Stuart Shaklan, Jet Propulsion Lab. (United States)

Published in SPIE Proceedings Vol. 9912:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
Ramón Navarro; James H. Burge, Editor(s)

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