<title>Performance analysis of self-referenced speckle holography</title>

Abstract

Self-referenced speckle holography (SRSH) is a post-detection turbulence-compensation technique for obtaining diffraction limited imagery from ground based telescopes degraded by atmospheric turbulence. In SRSH image plane information is used together with wave front distortion information to reconstruct an estimate of the object spectrum. The wave front distortion information is obtained from a wave front sensor (WFS) in the pupil plane of the telescope. The data from the WFS is used in a post-processing environment to estimate the point spread function (PSF) of the combined telescope and atmosphere. The PSF is then used to obtain an estimate of the object via deconvolution. We present the results of a detailed performance analysis of SRSH. Performance is quantified in terms of a 'system transfer function' and a 'system point spread function'. The results show how the performance of the technique is dependent on the WFS sampling intervals and shot noise. The results also indicate how the technique, for a given set of design parameters, responds to changing seeing conditions. For subaperture dimensions on the order of a Fried coherence cell size ro and adequate light levels, SRSH boosts the high spatial frequencies (those near the diffraction limit of the telescope) to nearly 0.6. The 'system strehl ratio' approaches 0.6.