Depolarization characteristics of polarized light in composite atmospheric channels and the influence of detection conditions.

During atmospheric propagation, laser beams are simultaneously affected by aerosol scattering and atmospheric turbulence. Furthermore, actual receiving systems are constrained by finite aperture size and exposure time. These factors collectively induce depolarization of the optical field, severely degrading the performance of equipment such as laser communication systems and lidar. To address the limitations of existing models, this paper improves upon current algorithms and constructs an atmospheric turbulence-scattering coupled coherent propagation model. Numerical simulations are carried out for the propagation of three types of polarized light through complex atmospheric environments. By employing coherent superposition to reconstruct the real speckle field at the receiving plane and subsequently calculating the Stokes vector, and by combining spatiotemporal averaging to simulate the integral measurement process of detectors, this work systematically reveals the intrinsic regulatory mechanisms of exposure time, receiving aperture, and atmospheric environmental parameters on polarization depolarization behavior and steady-state evolution. This study provides theoretical support for polarization state selection and receiving system parameter optimization in atmospheric free-space optical communication and polarization imaging.