Amplitude fluctuations in curvature sensing: comparison of two schemes

Abstract

The influence of amplitude fluctuations on the quality of phase reconstruction in curvature sensing is investigated. Two curvature schemes are compared: one with two symmetrically-defocused images (Roddier scheme) and one with a single defocused image (Hickson scheme). It is shown that the accuracy of phase reconstruction with the Hickson scheme is strongly aected even by low-level amplitude fluctuations, while the Roddier scheme works well under quite strong amplitude fluctuations.