Design, fabrication, and testing of stellar coronagraphs for exoplanet imaging
AffiliationUniv Arizona, Coll Opt Sci
Univ Arizona, Steward Observ
MetadataShow full item record
PublisherSPIE-INT SOC OPTICAL ENGINEERING
CitationJustin M. Knight, John Brewer, Ryan Hamilton, Karen Ward, Tom D. Milster, Olivier Guyon, "Design, fabrication, and testing of stellar coronagraphs for exoplanet imaging", Proc. SPIE 10400, Techniques and Instrumentation for Detection of Exoplanets VIII, 104000N (12 September 2017); doi: 10.1117/12.2273558; https://doi.org/10.1117/12.2273558
Rights© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).
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AbstractComplex-mask coronagraphs destructively interfere unwanted starlight with itself to enable direct imaging of exoplanets. This is accomplished using a focal plane mask (FPM); a FPM can be a simple occulter mask, or in the case of a complex-mask, is a multi-zoned device designed to phase-shift starlight over multiple wavelengths to create a deep achromatic null in the stellar point spread function. Creating these masks requires microfabrication techniques, yet many such methods remain largely unexplored in this context. We explore methods of fabrication of complex FPMs for a Phased-Induced Amplitude Apodization Complex-Mask Coronagraph (PIAACMC). Previous FPM fabrication efforts for PIAACMC have concentrated on mask manufacturability while modeling science yield, as well as assessing broadband wavelength operation. Moreover current fabrication efforts are concentrated on assessing coronagraph performance given a single approach. We present FPMs fabricated using several process paths, including deep reactive ion etching and focused ion beam etching using a silicon substrate. The characteristic size of the mask features is 5 mu m with depths ranging over 1 mu m. The masks are characterized for manufacturing quality using an optical interferometer and a scanning electron microscope. Initial testing is performed at the Subaru Extreme Adaptive Optics testbed, providing a baseline for future experiments to determine and improve coronagraph performance within fabrication tolerances.
VersionFinal published version
SponsorsTRIF optics; NASA ExEP SCDA Study