2005/05/31 by Olivier Guyon · 268 citations
Engineering · Physics and Astronomy · #Adaptive optics #Adaptive optics and wavefront sensing #Calibration and Measurement Techniques #Contrast (vision) #Detector #Optical Systems and Laser Technology #Optical transfer function #Optics #Physics #Point spread function #Scintillation #Telescope #Wavefront #Zernike polynomials #astro-ph
paper · pdf · doi:10.1086/431209
published in The Astrophysical Journal 629(1), 592-614 (IOP Publishing) · 31 pages, 17 figures, published in ApJ. Updated on Sep 29, 2005: Corrected error in equ. (29) and changed figures accordingly (thanks to T. Fusco for spotting the mistake)
openalex publication_date 2005/08/03 · arxiv created 2005/09/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The effects of photon noise, aliasing, wave front chromaticity, and scintillation on the point-spread function (PSF) contrast achievable with ground-based adaptive optics (AO) are evaluated for different wave front sensing schemes. I show that a wave front sensor (WFS) based on the Zernike phase contrast technique offers the best sensitivity to photon noise at all spatial frequencies, while the Shack-Hartmann WFS is significantly less sensitive. In AO systems performing wave front sensing in the visible and scientific imaging in the near-IR, the PSF contrast limit is set by the scintillation chromaticity induced by Fresnel propagation through the atmosphere. On an 8 m telescope, the PSF contrast is then limited to 10 -4 to 10 -5 in the central arcsecond. Wave front sensing and scientific imaging should therefore be done at the same wavelength, in which case, on bright sources, PSF contrasts between 10 -6 and 10 -7 can be achieved within 1'' on an 8 m telescope in optical/near-IR. The impact of atmospheric turbulence parameters (seeing, wind speed, turbulence profile) on the PSF contrast is quantified. I show that a focal plane wave front sensing scheme offers unique advantages, and I discuss how to implement it. Coronagraphic options are also briefly discussed.