Propagation characteristics of vortex beams in underwater channels based on a semi-analytical electric-field monte carlo model

Vortex beams possess unique phase and intensity distributions that endow them with superior scattering resistance, making them highly promising for underwater wireless optical communication and laser ranging. To accurately characterize their transmission behavior, this study proposes a semi-analytical electric-field Monte Carlo (SAEMC) model that, for the first time, jointly incorporates suspended-particle scattering and turbulence perturbations. The model integrates generalized Mie theory with electric-field-based photon tracking, and introduces the turbulence power spectrum at the optical-field level, thereby achieving high-accuracy modeling of the energy transport characteristics of vortex beams in complex water channels. Simulation and experimental results demonstrate that, compared with Gaussian beams, Laguerre-Gaussian vortex beams exhibit stronger penetration capability and greater resistance to multiple scattering under identical water conditions. Furthermore, the results reveal a distinct dependence of turbulence-induced intensity attenuation on particle concentration: turbulence dominates energy loss in clear water, whereas at higher particle concentrations, multiple scattering prevails and significantly suppresses the influence of turbulence. The proposed SAEMC model provides a more accurate physical framework for describing underwater vortex beam propagation and offers valuable theoretical guidance for the design and optimization of next-generation high-capacity Underwater Wireless Optical Communication (UWOC) systems.