8 October 2005 Speckle lifetimes in high-contrast adaptive optics
Author Affiliations +
Abstract
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.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Bruce Macintosh, Bruce Macintosh, Lisa Poyneer, Lisa Poyneer, Anand Sivaramakrishnan, Anand Sivaramakrishnan, Christian Marois, Christian Marois, } "Speckle lifetimes in high-contrast adaptive optics", Proc. SPIE 5903, Astronomical Adaptive Optics Systems and Applications II, 59030J (8 October 2005); doi: 10.1117/12.627854; https://doi.org/10.1117/12.627854
PROCEEDINGS
8 PAGES


SHARE
RELATED CONTENT


Back to Top