Effects of the atmospheric phase fluctuation on long-distance measurement.

Using a phase-locked interferometer, the phase fluctuation of laser beam propagation in the field has been investigated as a function of path length and beam spacing over the wide-frequency range. The higher frequency portion of the result shows good agreement with the result reported by Clifford. The variance of the averaged data follows a −1/3 power law for the theoretical averaging time in the homogeneous field. Using these data, the effect of the phase fluctuation is analyzed on practical long-distance measurements by a two-color method.