Research on correction mechanisms for atmospheric turbulence effects in long-range transmission scenarios

The transmission of lasers in the atmosphere is significantly affected by turbulence effects, and Adaptive Optics (AO) technology plays a certain role in improving beam quality. The AO system has achieved good results in correcting turbulence phase differences during slant upward laser transmissions, but its effectiveness in horizontal transmissions is not ideal. This article is based on ideal phase correction, which disregards the calibration errors associated with the AO system, and investigates the range of Fresnel numbers where the principle of phase conjugation is effective, as well as the limits of turbulence correction. By using the laser simulation platform EasyLaser, we set up simulated scenarios for laser slant upward transmission and horizontal transmission, revealing the correction rules of atmospheric turbulence effects in both transmission scenarios. The results show that in slant upward transmission, the far-field spot after ideal phase correction consistently approaches the diffraction limit, but the AO system almost fails under strong turbulence; in horizontal transmission, the beam is severely modulated by turbulence during transmission, with neither ideal phase correction nor the AO system providing correction effects, leading to the failure of the phase conjugation principle. However, correction ability gradually recovers when the Fresnel number exceeds the critical value (NF = 1.2).