Localized measurements of refractive turbulence using spatial filtering of scintillations

Remote measurements of refractive turbulence strength with high spatial resolution are demonstrated. The technique uses spatial and temporal filtering of scintillation from a spatially filtered incoherent optical source. Spatial resolution as fine as 4.5 m was observed at the center of a 110-m propagation path. An analytic approximation to the theory agrees very well with the data. This theory predicts the spatial resolution of a system of this type to be in the vicinity of the path length divided by the total number of cycles in the transmitter and receiver spatial filters.