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WFIRST will include the first high-contrast stellar coronagraph instrument ever flown, utilizing optical components. JPL is developing coronagraph technology using the Astrophysics Focused Telescope Assets (AFTA) on the NASA Wide-Field Infrared Survey Telescope (WFIRST).
Above: WFIRST will include the first high-contrast stellar coronagraph instrument ever flown, utilizing optical components. JPL is developing coronagraph technology using the Astrophysics Focused Telescope Assets (AFTA) on the NASA Wide-Field Infrared Survey Telescope (WFIRST).

Occulting Masks

Blocking the Starlight to See Exoplanets Directly

Daniel Wilson
JPL is developing coronagraph technology to enable direct imaging and spectroscopy of exoplanets using the Astrophysics Focused Telescope Assets (AFTA) on the NASA Wide-Field Infrared Survey Telescope (WFIRST). MDL is developing techniques for fabricating two types of starlight-occulting masks, one for the hybrid Lyot coronagraph (HLC) design, and another for the phase-induced amplitude apodization complex mask coronagraph (PIAACMC) design.

The HLC mask is a circular metal spot with a precisely aligned gray scale e-beam profiled dielectric pattern on top. The PIAACMC mask is an array of circular sections with precisely designed gray scale depths. Both types of masks work in conjunction with the rest of their respective coronagraph optics to suppress the light of a star by nearly 10 orders of magnitude to enable direct imaging and spectroscopy of the star’s exoplanets and debris disk.

After an initial process development phase, we successfully fabricated, precisely characterized, and delivered prototypes of both types of masks to the JPL coronagraph teams for optical performance evaluation.
An atomic force microscope surface profile image of an e-beam-fabricated HLC occulting mask.
An atomic force microscope surface profile image of an e-beam-fabricated HLC occulting mask.
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Microscope photo and atomic force microscope surface profile of an e-beam fabricated occulting mask for the AFTA hybrid Lyot coronagraph (HLC).
Microscope photo and atomic force microscope surface profile of an e-beam fabricated occulting mask for the AFTA hybrid Lyot coronagraph (HLC).
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