Correlation function of angle-of-arrival measurements with one-dimensional Shack-Hartmann wavefront sensor

Abstract

Laboratory turbulence generator has been established by heaters and fans. Turbulence of different strength is able to be simulated by changing the temperature. Plane Shack-Hartmann wave-front sensor is used to measure turbulence. The measurement indicates that turbulence has properties of locally homogeneity and isotropy approximately.One-dimensional Shack-Hartmann wave-front sensor with high temporal sampling frequency and spatial resolution is designed, which is made up of 28×1 cylindrical microlens array and linear CCD with frame frequency from 100Hz to 3000Hz. Wave-front after propagating through the laboratory generated turbulence is measured by the wave-front sensor. From displacement of the intensity centroid, the components of angle-of-arrival fluctuation in different positions along linear CCD direction are acquired. One-dimensional correlation function of angle-of-arrival is estimated.Under the hypothesis of locally homogeneous and isotropic random field, it is convenient to derive one-dimensional correlation function of angle-of-arrival by method of spectrum analysis of random processes with stationary increment. The result of experiment indicates that one-dimensional correlation function of angle-of-arrival confirms to the theoretical derivation approximately.