We present the results of measurements of the optical phase variations on a short line-of-sight path through the turbulent atmosphere. A helium-neon laser (6328 Å) propagates along a folded 50-m path that is one arm of a Michelson interferometer, and its interference fringes are observed. A measured time-lagged structure function, found by using Taylor’s hypothesis, compares well with the theoretical predictions of Tatarski for a broad range of effective separations, in contrast with earlier observations. Simultaneous measurements of <i>C</i><sub>n</sub><sup>2</sup> are made to facilitate comparison with theory. Values of the outer scale, deduced from temperature measurements at a different time at the same location, indicate excellent agreement with the spacing corresponding to the knee of the observed phase structure function, a result predicted by Tatarski’s theory and not previously observed.
G. M. B. BOURICIUS and S. F. CLIFFORD, "Experimental Study of Atmospherically Induced Phase Fluctuations in an Optical Signal," J. Opt. Soc. Am. 60, 1484-1489 (1970)