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5 October 2005 Study of high-performance coronagraphic techniques
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SAO has set up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase and/or amplitude) in combination with a second occulter for speckle light suppression. Here we are describing the initial testbed configuration. In addition, the testbed will be used to test a new approach of the phase diversity method to retrieve the speckle phase and amplitude. This method requires measurements of the speckle pattern in the focal plane and slightly out-of-focus. Then we will calculate a phase of the wave from which we can derive a correction function for the speckle corrector. Furthermore we report results from a parallel program which studies new manufacturing methods of soft-edge occulter masks. Masks were manufactured using the spherical caps method. Since the results were not satisfying we also investigated the method of ion beam milling of masks. Here we will present the outline of this method. Masks manufactured with both methods will be fully characterized in our mask tester before their use in the testbed.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Volker Tolls, Michael Aziz, Robert A. Gonsalves, Sylvain Korzennik, Antoine Labeyrie, Richard Lyon, Gary Melnick, Steve Somerstein, Gopal Vasudevan, and Robert Woodruff "Study of high-performance coronagraphic techniques", Proc. SPIE 5905, Techniques and Instrumentation for Detection of Exoplanets II, 59051M (5 October 2005);


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