Effects of diffraction and static wavefront errors on high-contrast imaging from the thirty meter telescope

Mitchell Troy, Ian Crossfield, Gary Chanan, Philip Dumont, Joseph J. Green, Bruce Macintosh
2006 Advances in Adaptive Optics II  
High-contrast imaging, particularly direct detection of extrasolar planets, is a major science driver for the next generation of extremely large telescopes such as the segmented Thirty Meter Telescope. This goal requires more than merely diffraction-limited imaging, but also attention to residual scattered light from wavefront errors and diffraction effects at the contrast level of 10 −8 -10 −9 . Using a wave-optics simulation of adaptive optics and a diffraction suppression system we
more » ... system we investigate diffraction from the segmentation geometry, intersegment gaps, obscuration by the secondary mirror and its supports. We find that the large obscurations pose a greater challenge than the much smaller segment gaps. In addition the impact of wavefront errors from the primary mirror, including segment alignment and figure errors, are analyzed. Segment-to-segment reflectivity variations and residual segment figure error will be the dominant error contributors from the primary mirror. Strategies to mitigate these errors are discussed.
doi:10.1117/12.671667 fatcat:g35ryoimazgddei2duifx2e4ca