Characterizing edge generated stray light sources for TPF coronagraph pupil masks

Daniel Ceperley, Andrew Neureuther, Michael Lieber, Jeremy Kasdin

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


The edge generated stray-light from corner boundary conditions, interactions with the lower mask structure, and surface plasmon polaritons that may limit Terrestrial Planet Finder Coronagraph performance are characterized. Previously a number of stray light sources, unaccounted for by the ideal thin mask theory used to design the pupil-plane masks, were identified. 1 In this paper we illustrate and quantify the most important outstanding stray-light sources in the near-field in order to improve the model of pupil-plane mask transmission used by the Integrated Telescope Model. 2 Corner spikes, caused by the need to bring the ideal top-hat field into compliance with the boundary conditions set forth by Maxwell's equations, form the strongest source of stray-light, accounting for up to a 1λ shift in the effective opening width per edge. Undercutting mask edges by 20° reduces this source of stray-light by more than a factor of five. Interactions between light and the lower mask structure, a secondary effect, account for only a few percent of the stray-light in the TE polarization but account for up to 50% of the stray-light in the TM polarization due to surface plasmon polaritons. Surface plasmon polaritons, surface waves that run for tens of microns and radiate at corners, form the final stray-light source. On thin masks they may account for up to a 1A shift in the effective opening width; however, their effects can be easily mitigated by choosing a poor surface plasmon material, such as Chrome. The results presented here are being used to facilitate end-to-end system modeling through the Integrated Telescope Model. 3.

Original languageEnglish (US)
Article number59050J
Pages (from-to)1-11
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2005
EventTechniques and Instrumentation for Detection of Exoplanets II - San Diego, CA, United States
Duration: Aug 2 2005Aug 4 2005

All Science Journal Classification (ASJC) codes

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


  • Corner spikes
  • Coronagraph. pupil mask
  • Edge effects
  • FDTD
  • Polarization
  • Surface plasmons
  • Vector propagation


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