Effects of atmospheric spectral decorrelation on visibility measurements in Michelson interferometry

We analyze the degrading effects of spectral decorrelation introduced by atmospheric turbulence on astronomical images obtained from a long-baseline Michelson interferometer. Our approach consists of a theoretical computation of the polychromatic spectrum, based on a numerical model of the atmospheric turbulence. The model uses the von Karman. definitions parameterized by the Fried parameter r(0) and the outer scale L(0). Through the theoretical analysis of fringe visibility estimated from. the polychromatic spectrum, we show how the turbulence model can reproduce visibility behavior with respect to the spectral bandwidth and the separation validation is realized by comparing theoretical to measured visibilities of a Cephei. The future use of this work is to calibrate these losses to improve the accuracy of the GI2T interferometer's observations. (C) 1997 Optical Society of America.