We experimentally study the variance of the transverse displacement, or wandering, of a laser beam after it has traveled through indoor artificially convective turbulence. In a previous paper (Opt. Commun., vol. 242, p. 57, November 2004) we have modeled the atmospheric turbulent refractive index as a fractional Brownian motion. As a consequence, a different behavior is predicted for the wandering variance: it grows with L, the path length, as L2+2H, where H is the Hurst exponent associated to the fractional Brownian motion. The traditional cubic dependence is only recovered when H = 1/2-the ordinary Brownian motion. This is the case of strong turbulence or long path length. Otherwise, for weak turbulence and short path length deviations from the usual expression should be found. In this work we experimentally confirm the previous assertion.
Bibliographical noteFunding Information:
G. Funes and D. Gulich have been supported financially by a student fellowship from the INNOVATEC Foundation, Argentina. L. Zunino has been supported financially by a postdoctoral research fellowship from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, Argentina). D.G. Pérez has been supported by Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, FONDECYT Project No. 11060512, Chile), and partially by Pontificia Universidad Católica de Valparaíso (PUCV, Project No. 123.786/2006, Chile). He is also very thankful to Prof. Dr. M. Garavaglia for his kind hospitality at Centro de Investigaciones Ópticas (CIOp), Argentina, where part of this work was done.
- Fractional Brownian motion
- Hurst exponent
- Indoor convective turbulence
- Laser beam wandering variance