Actions for Speckle lifetime in high-contrast adaptive optics [electronic resource].

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Speckle lifetime in high-contrast adaptive optics [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2005.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
PDF-file: 10 pages; size: 0.7 Mbytes
Additional Creators
Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
The main noise source in detection of faint companions such as extrasolar planets near bright stars with AO is speckle noise - residual PSF structure caused by wavefront errors due to the atmosphere, the AO system, and static optical effects. Of these, the most fundamental are atmospheric speckles - even given infinite wavefront SNR and a perfect DM, timelag between sensing and correction will always lead to a residual atmospheric speckle pattern. There have been several suggestions as to the lifetime of these atmospheric speckles, none strongly supported by theory or simulation. We have carried out a systematic series of simulations and analysis to explore this question. We show that speckles have different behavior in the regime in which diffraction is significant (first-order speckles, which are rapidly modulated as a phase error translates across the aperture) and in the coronagraphic regime (second-order speckles, which evolve only as the phase screen completely clears the aperture). We use simulations to analyze the behavior of speckles in a variety of regimes, showing that the second-order atmospheric speckle lifetime is almost constant irrespective of the properties of the AO system, and is set primarily by the atmospheric clearing time of the telescope aperture.
Report Numbers
E 1.99:ucrl-conf-214737
ucrl-conf-214737
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Note
Published through SciTech Connect.
08/19/2005.
"ucrl-conf-214737"
Presented at: SPIE Conference on Astronomical Adaptive Optics Systems and Applications II, San Diego, CA, United States, Jul 31 - Aug 04, 2005.
Poyneer, L; Macintosh, B; Marois, C; Sivaramakrishnan, A.
Funding Information
W-7405-ENG-48
View MARC record | catkey: 13823779