The Strehl efficiency of adaptive optics systems

摘要

Strehl ratios achieved on bright guide stars by 19 adaptive optics (AO) systems of various dimensions are examined. Both types of systems exhibit a similarly stronger attenuation of instrumental aberrations with smaller subapertures. With the same number of wave-front sensor subapertures, curvature systems are generally found to be more efficient than Shack-Hartmann systems at attenuating turbulence-induced optical phase variance. Consequently, curvature systems use. fainter guide stars to achieve the same performance as Shack-Hartmann systems. The contrast is stronger for larger systems. Possible causes of these differences are discussed. Calibration errors of non-common-path aberrations appear to be the most important. The compensation of the guide star image itself seems to be beneficial for large curvature systems. The likely performance of future very large systems are briefly discussed. A plea is made to encourage astronomical AO teams to uniformly and optimally characterize the on-sky performance of their systems.