Abstract

We have developed approximate expressions for the aperture-averaging factor of optical scintillation in the turbulent atmosphere. For large apertures and weak path-integrated turbulence with small inner scale, the variance of signal fluctuations is proportional to the -7/3 power of the ratio of the aperture diameter to the Fresnel-zone size. If the inner scale is large, the variance is proportional to the -7/3 power of the ratio of the aperture diameter to the inner scale. The constant of proportionality depends on whether the initial wave is a plane wave or spherical wave. In strong path-integrated turbulence, two scales develop. That portion of the variance associated with the smaller scale is proportional to the -2 power of the ratio of the aperture diameter to the phase-coherence length, which depends on inner scale. That portion of the variance associated with the larger scale is proportional to the -7/3 power of ratio of the aperture diameter to the scattering disk, which is defined as the square of the Fresnel-zone size divided by the phase-coherence length.

© 1990 Optical Society of America