We numerically study a method to increase the photon return flux of continuous-wave laser guide stars using one-dimensional atomic cooling principles. The method relies on chirping the laser towards higher frequencies following the change in velocity of sodium atoms due to recoil, which raises atomic populations available for laser excitation within the Doppler distribution. The efficiency of this effect grows with the average number of atomic excitations between two atomic collisions in the mesosphere. We find the parameters for maximizing the return flux and evaluate the performance of chirping for operation at La Palma. According to our simulations, the optimal chirp rate lies between $ 0.8 {{-}} 1.0 \;{\rm MHz}/\unicode{x00B5} {\rm s} $, and an increase in the fluorescence of the sodium guide star up to 60% can be achieved with current 20-W-class guide star lasers.

中文翻译：

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频率chi连续波钠激光导星：建模和优化

我们用一维原子冷却原理数值研究了一种增加连续波激光导星的光子返回通量的方法。该方法依赖于由于反冲而使钠原子速度发生变化，从而使激光器向更高的频率线性调频，这增加了多普勒分布内可用于激光激发的原子数量。这种效应的效率随着中层中两次原子碰撞之间平均原子激发数的增加而增加。我们找到了使返回通量最大化的参数，并评估了拉帕尔玛岛chi运行的性能。根据我们的模拟，最佳线性调频率介于$ 0.8 {{-}} 1.0 \; {\ rm MHz} / \ unicode {x00B5} {\ rm s} $，并且使用目前的20 W级导星激光器可以将钠导星的荧光提高到60％。