Measurements of the level of turbulence C2n have been successfully performed with the optical scintillometer. The success of this instrument is based on the observed fact that the variance of aperture averaged scintillation is described by weak scattering theory even for conditions in which strong scintillation is observed for point detectors. However, for sufficiently long propagation paths, the aperture averaged variance is affected by strong scattering. The effects of strong scattering are calculated theoretically and compared to experimental results. The physics of this regime are discussed and the important parameters investigated. The new range of validity of the optical scintillometer is discussed.
Rod G. Frehlich and G. R. Ochs, "Effects of saturation on the optical scintillometer," Appl. Opt. 29, 548-553 (1990)