Wind and refractive-turbulence sensing using crossed laser beams.

The theory of optical propagation through atmospheric turbulence demonstrates the sensitivity of such quantities as log-amplitude variance and covariance to strength of refractive turbulence and transverse wind. We exploit this sensitivity by using a crossed-path technique to derive path profiles of these quantities. The results are insensitive to changes in the spatial spectrum of the refractive-index variations. The path resolution is easily varied by changing the receiver and transmitter separations and is ultimately limited by signal-to-noise considerations. The experimental results for horizontal paths, described here, will ultimately be used to indicate the feasibility of profiling on vertical paths with passive sources.