Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2009 · 24 citations · 5 references
Natural SciencesAstronomyPhysicsAstrophysicsOptical AstronomyOpticsDetector TechnologySolar CoronaElectron Beam Lithography MasksHigh-contrast ImagingMask Interface DesignMask Set Design
The NIRCam instrument on the James Webb Space Telescope will provide coronagraphic imaging from λ =1-5 μm of high contrast sources such as extrasolar planets and circumstellar disks. A Lyot coronagraph with a variety of circular and wedge-shaped occulting masks and matching Lyot pupil stops will be implemented. The occulters approximate grayscale transmission profiles using halftone binary patterns comprising wavelength-sized metal dots on anti-reflection coated sapphire substrates. The mask patterns are being created in the Micro Devices Laboratory at the Jet Propulsion Laboratory using electron beam lithography. Samples of these occulters have been successfully evaluated in a coronagraphic testbed. In a separate process, the complex apertures that form the Lyot stops will be deposited onto optical wedges. The NIRCam coronagraph flight components are expected to be completed this year.
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