Tolerance analysis of a self-coherent camera for wavefront sensing and dark hole maintenance

Kevin Z. Derby, Sebastiaan Haffert, Jaren Ashcraft, Kian Milani, Heejoo Choi, Young Sik Kim, Laird Close, Christopher Mendillo, Supriya Chakrabarti, Greg Allan, Leonid Pogorelyuk, Kerri Cahoy, Mamadou N'Diaye, Daewook Kim, Jared Males, Ewan Douglas

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

2 Scopus citations


Exceptional wavefront correction is required for coronagraphs on future space observatories to reach 10-10 contrasts for direct imaging of rocky exoplanets around Sun-like stars. This picometer level wavefront correction must be stable over long periods of time and should be limited only by photon noise and wavefront sensing architecture. Thus, wavefront errors that arise from optical surface errors, thermal gradients, pointing induced beamwalk, and polarization aberration must be tightly controlled. A self-coherent camera (SCC) allows for image plane correction of mid-spatial frequency errors and a continuous means of dark-hole maintenance. By introducing a reference pinhole at the Lyot stop of a coronagraph, coherent starlight can be interfered with image plane speckles while leaving incoherent planet light untouched. A coronagraph model was created using High Contrast Imaging in Python (HCIPy) to simulate the SCC. Using these tools, realistic input disturbances can be introduced to analyze wavefront sensor performance. Using our model, we first demonstrate the necessity of a complimentary low-order wavefront sensor (LOWFS) to be paired with the SCC. Next, we discuss considerations when creating the modified Lyot stop of an SCC. Finally, a tolerance analysis of the SCC in the presence of optical surface errors, beamwalk due to pointing errors, photon noise, and detector read noise is presented.

Original languageEnglish (US)
Title of host publicationSpace Telescopes and Instrumentation 2022
Subtitle of host publicationOptical, Infrared, and Millimeter Wave
EditorsLaura E. Coyle, Shuji Matsuura, Marshall D. Perrin
ISBN (Electronic)9781510653412
StatePublished - 2022
EventSpace Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave - Montreal, Canada
Duration: Jul 17 2022Jul 22 2022

Publication series

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


ConferenceSpace Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave


  • coronagraphy
  • high-contrast imaging
  • physical optics modeling
  • Self-coherent camera
  • wavefront control
  • wavefront sensing

ASJC Scopus subject areas

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


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