The hard-aperture effect on self-focusing of high-power laser beams propagating from the ground through the atmosphere to space orbits is studied. It is shown that the spot size on the target increases as the truncation parameter decreases and the beam power increases. However, as the truncation parameter decreases, the apertured laser beam is less affected by self-focusing. On the other hand, two effective design rules are presented to optimize the intensity on the target, i.e., the optimal power and the optimal focal length. It is proven that the self-focusing effect and the hard-aperture effect both can be compensated by applying the optimal initial beam defocusing. It is also found that the higher maximum intensity on the target will occur by applying the optimal focal length rather than the optimal power.

中文翻译：

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硬孔径对大气中传播的高功率激光束自聚焦的影响

研究了硬孔径对从地面穿过大气层传播到太空轨道的高功率激光束自聚焦的影响。结果表明，目标上的光斑尺寸随着截断参数的减小和光束功率的增加而增加。然而，随着截断参数的减小，孔径激光束受自聚焦的影响较小。另一方面，提出了两个有效的设计规则来优化目标上的强度，即最佳功率和最佳焦距。证明了自聚焦效应和硬孔径效应都可以通过应用最佳初始光束散焦来补偿。还发现通过应用最佳焦距而不是最佳功率将在目标上产生更高的最大强度。