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3 March 2003 Eclipse apodization: realization of occulting spots and Lyot masks
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A key element in the Eclipse coronagraph is the apodized occulting spot. For exo-planet detection in the presence of a sun-like star, the specification for intensity transmittance at the center of the spot is less than 1×10-8. It must also taper smoothly with a desired functional form to avoid diffraction artifacts in the angular region of planet detection. From a fabrication point of view, these requirements are very challenging. A candidate technology for fabricating such spots is electron-beam exposure of high-energy beam sensitive (HEBS) glass (a product of Canyon Materials, San Diego, CA). In this work, we have calibrated HEBS glass optical density as a function of electron-beam exposure and attained optical densities up to 7.66 without saturation. We then fabricated occulting spots having various functional forms including circular Gaussian, one-dimensional sinc2, and circular sinc2. Preliminary quantitative analysis of the circular sinc2 occulting spot is encouraging.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Daniel W. Wilson, Paul D. Maker, John T. Trauger, and Tony B. Hull "Eclipse apodization: realization of occulting spots and Lyot masks", Proc. SPIE 4860, High-Contrast Imaging for Exo-Planet Detection, (3 March 2003);

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