Performance analysis of the self-referenced speckle-holography image-reconstruction technique.

Self-referenced speckle holography (SRSH) is a postdetection 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 in the pupil plane of the telescope. This information is used in a postprocessing environment to estimate the point spread function of the combined telescope and atmosphere. The point spread function is then used to obtain an estimate of the object intensity distribution by 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 SRSH is dependent on the sampling intervals and shot noise in the wave-front sensor. The results also indicate how the technique, for a given set of design parameters, responds to changing seeing conditions. For wave-front sensor sampling intervals of the order of a Fried coherence cell size r(0) and adequate light levels, SRSH boosts the high spatial frequencies (those near the diffraction limit of the telescope) to nearly 0.6.