The model of laser return field backscattered by the atmospheric aerosols is established based on the Huygens-Fresnel diffraction integral formula in weak turbulence environment. The laser transmission properties in turbulent atmosphere provide the foundation to study the laser return field. The characteristics of intensity, complex coherence degree and the backscattering enhancement effect of laser return are analyzed under typical laser source coherence, turbulence, optical transceiver diameters and beam truncations. The laser source partial coherence reduces the coherence of laser return in turbulent environments. For the laser source beams with the same coherence degree, the laser intensities on the aerosols plane change relatively less with the increase of turbulence and detection range when the optical aperture is smaller; however, the laser return complex coherence degree is higher using larger optical transceiver in turbulent atmosphere. Moreover, the backscattering enhancement effect is mainly related to the turbulence, especially in the far field. The research is of significance to reveal the heterodyne detection process and the optimization method of coherent lidar systems.
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