Abstract

A reasonably complete understanding of the phenomenon of the saturation of the scintillation of a lightwave propagated through strong atmospheric turbulence now exists. Some questions remain, however, about the nature of very small details in the scintillation pattern, that is, those around the inner scale and smaller. We present some observations of the fine structure of intensity scintillation, with concurrent independent measurements of refractive-index turbulence and inner scale made over a 1-km path. Quantitative measurements of the spatial covariance were made by continuously cycling the spacing of two 1-mm diam detectors, by operating continuously at fixed spacings, and by converting the temporal frequency observed by a small-diameter detector, moving at high speed in a circular pattern, to spatial wavelength. Qualitative information was also obtained through high-speed photographs. Details much smaller than the inner scale, which did not arise from the last few meters of the path, were observed by all techniques.

© 1986 Optical Society of America