Scintillation reduction by use of multiple Gaussian laser beams with   different wavelengths
  We study the scintillation index of N partially overlapping collimated lowest order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Using the Rytov approximation we calculate the initial beam separation that minimizes the longitudinal scintillation. Further reduction of the longitudinal scintillation is obtained by optimizing with respect to both beam separation and spot size. The longitudinal scintillation of the optimal N-beam configurations is inversely proportional to N, resulting in a 92% reduction for a 9-beam system compared with the single beam value. The radial scintillation values for the optimal N-beam configurations are significantly smaller than the corresponding single beam values. 
Avner Peleg, Jerome V. Moloney