Behavior of the laser beam wandering variance with the turbulent pathlength

G. FUNES, D. GULICH, L. ZUNINO, D. G. PÉREZ AND M. GARAVAGLIA

OPTICS COMMUNICATIONS

Año: 2006 vol. 272 p. 476 - 479

0030-4018

We experimentally study the variance of the transverse displacement,or wandering,of a laser beam after it has traveled through indoor arti .cially 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 di .erent behavior is predicted for the wan- dering variance:it grows with L ,the path length,as LL ,the path length,as L 2+2 HH ,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 con .rm the previous assertion. 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 con .rm the previous assertion. 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 con .rm the previous assertion. 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 con .rm the previous assertion. 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 con .rm the previous assertion. 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 con .rm the previous assertion. 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 con .rm the previous assertion. 2006 Elsevier B.V.All rights reserved.2006 Elsevier B.V.All rights reserved. PACS:42.25.Dd;47.27.i;47.27.Eb;47.53.+n;02.50.Ey;02.50.Ga;02.50.Fz42.25.Dd;47.27.i;47.27.Eb;47.53.+n;02.50.Ey;02.50.Ga;02.50.Fz Keywords:Indoor convective turbulence;Laser beam wandering variance;Fractional Brownian motion;Hurst exponentIndoor convective turbulence;Laser beam wandering variance;Fractional Brownian motion;Hurst exponent