Abstract

Measurements have been made of the scintillation of a laser beam after propagating over an 8-km path near the ground. The measurements were made with collection apertures ranging from 1 mm to 1 m in diameter. The probability distribution of the scintillation was found to be log-normal for all collector diameters. The log-normal variance decreased smoothly for diameters from 1 mm to about 10 cm, but showed no decrease between 10 cm and 1 m. A hypothesis is offered which explains those results which are anomalous in terms of present theories. Measurements of the log-normal variance were made over extensive periods on three days, during winter, spring, and summer. From these the atmosphere’s refractive-index structure constant, C_N², was computed. Values of C_N² were found to be fairly constant over the full range of measurements, falling between 3 and $6\times {10}^{-15}{\text{m}}^{-\frac{2}{3}}$, except near sunrise and sunset, when values of about $1\times {10}^{-15}{\text{m}}^{-\frac{2}{3}}$ were more typical.

© 1967 Optical Society of America

Laser-Beam Scintillation in the Atmosphere

D. L. Fried and J. B. Seidman
J. Opt. Soc. Am. 57(2) 181-185 (1967)

Airborne laser-beam scintillation measurements at high altitudes*

Glen J. Morris
J. Opt. Soc. Am. 63(3) 263-270 (1973)

The Effect of Atmospheric Scintillation on an Optical Data Channel–Laser Radar and Binary Communications

D. L. Fried and R. A. Schmeltzer
Appl. Opt. 6(10) 1729-1737 (1967)

Wavelength Dependence of Laser-Beam Scintillation*

Michael W. Fitzmaurice, Jack L. Bufton, and Peter O. Minott
J. Opt. Soc. Am. 59(1) 7-10 (1969)

Aperture Averaging of Scintillation

D. L. Fried
J. Opt. Soc. Am. 57(2) 169-175 (1967)