Evaluation of the performance of a shearing interferometer in strong scintillation in the absence of additive measurement noise

Abstract

A simulation study is presented that evaluates the ability of a unit-shear, shearing interferometer to estimate a complex field resulting from propagation through extended turbulence. Performance is defined in terms of the Strehl ratio achieved when the estimate of the complex field obtained from reconstruction is used to correct the distorted wave front presented to the wave-front sensor. A series of evaluations is performed to identify the strengths and weaknesses of the shearing interferometer in the two-dimensional space of the Fried parameter r0 and the Rytov number. The performance of the shearing interferometer is compared with that of a Hartmann sensor in the Fried and Hutchin geometries. Although the effects of additive measurement noise (such as read noise, shot noise, amplifier noise) are neglected, the fundamental characteristics of the measurement process are shown to distinguish the performance of the various wave-front sensors. It is found that the performance of a shearing interferometer is superior to that of a Hartmann sensor when the Rytov number exceeds 0.2.