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高斯光束的传播特性直接影响激光雷达大气回波信号的发散角,进而影响法布里-珀罗标准具(FPE)的光学特性。从高斯光束的FPE三维干涉环分析,得到发散角小的高斯光束有利于获得能量较高的FPE零级或一级干涉环。探讨了高斯光束品质因子M2和准直倍率对不同高度的激光大气回波信号的影响。数值计算结果表明,FPE对大气回波信号的透射率与高度的变化有关,在近场变化明显,在远场相对稳定;且对特定高度大气回波信号的FPE透射率随着光束品质因子M2的增大而降低,随着准直倍率的放大而增强。所以应设计和选择具有较高准直倍率的准直发射系统和具有较低光束品质因子M2的激光光束,来提高FPE的透射率,同时对以FPE分光的激光雷达的近场回波信号进行FPE透射率校正,以改善激光雷达系统的测量误差。
The propagation characteristics of Gaussian beams directly affect the divergence angle of the lidar atmospheric echo signal, which affects the optical characteristics of Fabry-Perot etalon (FPE). From Gaussian beam FPE three-dimensional interference ring analysis, the Gaussian beam with small divergence angle is obtained to obtain the higher energy FPE zero-order or first-order interference ring. The influence of Gaussian beam quality factor M2 and collimation magnitudes on laser atmospheric echo signals at different heights is discussed. The numerical results show that FPE is related to the change of altitude and atmospheric transmittance. The variation of FPE in the near-field is obvious and the far-field is relatively stable. The FPE transmittance of FPE with the beam quality factor M2 Of the increase and decrease, with the enlargement of the magnification and enhanced. Therefore, a collimation transmitting system with a higher collimation magnification and a laser beam with a lower beam quality factor M2 should be designed and selected to improve the transmittance of the FPE. At the same time, near-field echo signals of the FPE-resolved lidar should be subjected to FPE Transmittance Correction to Improve Measurement Error in Lidar Systems.