Average spreading and beam quality evolution of Gaussian array beams propagating through oceanic turbulence

The propagation properties of a radial Gaussian beam array through oceanic turbulence are studied analytically. The analytical expressions for the average intensity and the beam quality (power-in-the-bucket (PIB) and M ²-factor) of a radial beam array in a turbulent ocean are derived based on an account of statistical optics methods, the extended Huygens-Fresnel principle, and the second order moments of the Wigner distribution function. The influences of w, ε, and χ _T on the average intensity are investigated. The array divergence increases and the laser beam spreads as the salinity-induced dominant, ε decreased, and χ _T increased. Further, the analytical expression of PIB and the M ²-factor in the target plane is obtained. The changes of PIB and the M ²-factor with three oceanic turbulence parameters indicate that the stronger turbulence with a larger w, smaller ε, and larger χ _T results in the value of PIB decreasing, the value of the M ²-factor increasing, and the beam quality degrading. (letter)