Behavior of the laser beam wandering with the turbulent path length

We experimentally study the variance of the transverse displacement (wandering) of a laser beam after it has traveled through indoor artificially convective turbulence. In a previous paper (Opt. Comm., Vol. 242, No 1-3, pp. 76-63, November 2004) we have modeled the atmospheric turbulent refractive index as a fractional Brownian motion. As a consequence, a different behavior is expected for the wandering variance. It behaves as L2+2H, where L is the propagation length and H the Hurst exponent associated to the fractional Brownian motion. The traditional cubic dependence is recovered when H = 1/2 - the ordinary Brownian motion. That is the case of strong turbulence or long propagation path length. Otherwise, for weak turbulence and short propagation path length some deviations from the usual expression should be found. In this presentation we experimentally confirm the previous assertion.