Diffraction-based analysis of tunnel size for a scaled external occulter testbed

Dan Sirbu, N. Jeremy Kasdin, Robert J. Vanderbei

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

For performance verification of an external occulter mask (also called a starshade), scaled testbeds have been developed to measure the suppression of the occulter shadow in the pupil plane and contrast in the image plane. For occulter experiments the scaling is typically performed by maintaining an equivalent Fresnel number. The original Princeton occulter testbed was oversized with respect to both input beam and shadow propagation to limit any diffraction effects due to finite testbed enclosure edges; however, to operate at realistic space-mission equivalent Fresnel numbers an extended testbed is currently under construction. With the longer propagation distances involved, diffraction effects due to the edge of the tunnel must now be considered in the experiment design. Here, we present a diffraction-based model of two separate tunnel effects. First, we consider the effect of tunnel-edge induced diffraction ringing upstream from the occulter mask. Second, we consider the diffraction effect due to clipping of the output shadow by the tunnel downstream from the occulter mask. These calculations are performed for a representative point design relevant to the new Princeton occulter experiment, but we also present an analytical relation that can be used for other propagation distances.

Original languageEnglish (US)
Title of host publicationSpace Telescopes and Instrumentation 2016
Subtitle of host publicationOptical, Infrared, and Millimeter Wave
EditorsHoward A. MacEwen, Makenzie Lystrup, Giovanni G. Fazio
PublisherSPIE
ISBN (Electronic)9781510601871
DOIs
StatePublished - 2016
EventSpace Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave - Edinburgh, United Kingdom
Duration: Jun 26 2016Jul 1 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9904
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherSpace Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave
CountryUnited Kingdom
CityEdinburgh
Period6/26/167/1/16

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Keywords

  • External occulters
  • High contrast imaging
  • Scalar diffraction
  • Starshades
  • Tunnel

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