高亮度的激光钠信标有利于提高自适应光学波前探测的准确性和灵敏度，但是在激光与钠原子作用的过程中，反冲和下抽运限制了钠原子激发态概率的增长，减小了钠原子的自发辐射速率和回波光子数。通过对窄带/宽带激光与钠原子作用产生反冲和下抽运效应的研究，结果表明：对于低能量的连续激光与大气中间层钠层作用，窄带激光反冲和下抽运效应比宽带激光严重，但是自发辐射速率比宽带激光大很多，获得的回波光子数明显多于宽带激光；对于宽带激光，其激发的回波光子数较少，但是具有不易饱和、反冲效应小的优点。

The bright laser sodium beacons are beneficial to enhance the accuracy and sensitivity of wavefront sensing. But the recoil and downpumping limit the increase of the excited state probability and decrease the sodium spontaneous radiation rate and the number of return photons in the process of laser interacting with sodium atoms. By investigating on the recoil and downpumping effects which the narrow band and broad band lasers act on sodium atoms in mesosphere, the conclusions show that the effects of recoil and downpumping of the narrow band laser are more severe than the ones of the broad band laser, but the spontaneous radiation rate is faster than that of the broad band laser and the number of return photons is distinctly more than the one excited by the broad band laser, when the low energy continuous wave laser interacts with the sodium layer in the mesosphere. However, the broad band laser has the easily unsaturated merit and the less recoil effcts.