Effects of oceanic turbulence on the propagation of four-petal Gaussian model beams

The evolution of average intensity for four-petal Gaussian model (FPGM) laser beams propagating through the oceanic turbulence is investigated. The analytical expressions of the average intensity at any receiver plane are derived based on the extended Huygens-Fresnel principle. Our results indicate that with the propagation distance increasing long enough in far field area, the initial profile of FPGM laser beams gradually disappears, and finally the profile converts into Gauss-like beam with several small petals. We also find that the spreading of the FPGM laser beam increases with the increasing of waist width of the Gaussian beam and equivalent temperature structure constant. The beam spreading decreases with the increasing of the dissipation rate of temperature variance and the inner scale of turbulence. The salinity fluctuation has a greater contribution to the spreading of the FPGM beam than that of the temperature fluctuation. Our results can be helpful for the design of the free space optical wireless communication and underwater imaging systems operating in oceanic environment.