Mutual Coherence Function and Frequency Spectrum of a Laser Beam Propagating Through Atmospheric Turbulence.

摘要

The mutual coherence function of a laser beam propagating in turbulence with a modified von Karman spectrum for the index of refraction fluctuations,including a parametric study of the effect on the MCF of varying beam size,focal length,and the properties of the turbulence was computed. The results are valid over all propagation distances,unlike calculations employing the method of smooth perturbations. Also studied was the effect of a constant wind on the frequency spectrum of signal. It was found that over most practical path lengths the spectral width is delta omega = 4.1V ((k sub o) sup 6/5)(z sup 3/5)((C sub n,sub 2) sup 3/5),where V is the wind speed, k sub o is the signal wavenumber, C sub n sup 2is the strength of turbulence,and z is the path length in the turbulence. (Modified author abstract)