Correction of random angular displacements of optical beams

gravity of an optical beam (traveling in a turbulent atmosphere) by tracking the random angular position of the center of gravity of theimage of a reference beam. The reference beam may be provided by an auxiliary source or it may represent part of the reflected original beam. It is shown that variance of the residual random angular displacements of the center of gravity of a beam can be reduced, under certain conditions, to not more than 25% of the same variance in the absence of correction. In particular, it is found that the proposed correction method is sufficiently effective for apertures smaller than the external scale of the turbulence. The time constant of the loop for the compensation of random displacements should be less than the ratio of the initial beam size to the average wind velocity.