Scintillation index of flat-topped beam through non-Kolmogorov turbulence

The mathematical formula of off-axis scintillation for flat-topped beam through non-Kolmogorov atmospheric turbulence is derived using the generalized non-Kolmogorov spectrum model and the equivalent structure constant based on the Born and Rytov perturbation methods. The variations of the off-axis scintillation at the receiver plane is analyzed comprehensively versus the radial distance. The results can correctly reduce to the existing off-axis intensity fluctuations of Gaussian beams in non-Kolmogorov turbulence. It is indicated that flat-topped beams possess much smaller off-axis scintillation indexes than that of Gaussian beams at large radial distance and the scintillation of flat-topped beam will suffer invariability even descend before increasing with the increment of radial distance. These results can be applied to research of flat-topped laser communication.