M. Wang, S. Thibault "CGH null design and fabrication for CFH telescope simulator" Proc. of SPIE, 5252:31-42, 2004
Abstract: A wavefront-generated simulator for Canada-France-Hawaii (CFH) 3.6-m telescope to test a novel wide-field IR camera (WIRCAM) of the telescope is presented. We investigate a Computer-Generated Hologram (CGH) wavefront generator to demonstrate off-axis aberrated wavefront generation with and with no rotational symmetry modes of Zernike polynomial as telescope wavefront simulator. A CGH simulator system to generate field optical performance of CFH telescope, while working on a F/3.8 prima focus with an field-of-view (FOV) of ±15 arcmin, is designed and computed for WIRCAM tests in optical labs for system performance evaluation. The CGH simulator is modeled as a diffractive surface defined by a phase function, and the optical phase function is specified by a Zernike polynomial phase equation. As the CGH simulator has to work in the first diffraction order, a carrier frequency must be added to the phase function in such a way to ensure the separation of the diffraction orders for eliminating unwanted light in the WIRCAM tests. Finally the nominal-design performance of the CGH simulator is compared with the tolerance analysis predictions as well as the system misalignment sensitivity.
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