Propagation characteristics study of radially polarized Gaussian vortex beam in ocean turbulence

Abstract

Based on the extended Huygens–Fresnel principle, a semi analytical expression of the radially polarized Gaussian vortex (RPGV) beam in ocean turbulence has been deduced. The influence of topological charge, propagation distance, laser wavelength, rate of dissipation of the mean-squared temperature χT, ratio of temperature or salinity contributions to the turbulence ω, rate of dissipation of kinetic energy per unit mass of fluid ε on the propagation characteristics are discussed in detail. The results show that the beams with higher topological charges can mitigate ocean turbulence effect. The scintillation index increases with the increase of propagation distance and laser wavelength and the decrease of topological charge. When χT is less than1×10−9K2/s, scintillation index increases with an increase of χT. When χT is larger than 1×10−9K2/s, saturation phenomenon of the scintillation index will appear. When propagation distance is less than 40 m, scintillation index increases with an increase of ω. However, when propagation distance is larger than 40 m, scintillation index increases with the decrease of ω. The propagation distance is very sensitive to the degree of polarization (DOP). The degree of polarization becomes worse with the increase of propagation distance, χT and ω and the decrease of topological charge and ε.