Competition between turbulence and thermal blooming of coherent vortex beam array propagating in non-Kolmogorov marine atmosphere

Abstract

The competition between turbulence and thermal blooming significantly affects the propagation characteristics of laser beams in the atmosphere. Here, taking the propagation of a vortex beam array in a non-Kolmogorov marine atmosphere as an example, we have quantitatively analyzed the competition between turbulence and thermal blooming. The atmospheric coherence length is adopted to evaluate the turbulence strength, while a modified thermal distortion parameter is developed to evaluate the thermal blooming strength of vortex beam arrays in non-Kolmogorov turbulence. Results indicate that, in strong turbulence, there is a significant variation in the beam characteristics at the target plane as the spectral power law index increases, whereas this relationship exhibits a smoother change in weak turbulence. More interestingly, our results suggest that for a fixed aperture of laser emission systems, increasing the initial power density may not always lead to a higher average power density at the target plane, and there exists an optimal value no matter what the intensity of the turbulence is, i.e., weak, moderate, and strong turbulence. We hope these results may provide useful guidance for laser communication, laser power transmission, etc.