Jiang Kai-jun, Wang Jin, Li Ke, He Ming, Tu Xian-hua, Zhan Ming-sheng
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2004 Jun;24(6):659-62.
Zeeman split takes place for the hyperfine level structure of neutral atoms where magnetic field exists. In addition, being excited by right circularly polarized light and left circularly polarized light, atoms obey different transition rules. So, the absorption peak between the hyperfine Zeeman level shifts with respect to the absorption peak without magnetic field. Accordingly, the authors demonstrated a kind of simple and flexible method to stabilize the frequency of diode laser. The linewidth of diode laser was reduced to less than 1 MHz using this method. Through analyzing the experiment results, the authors found that when the sum of both shifts of the hyperfine level of atoms excited by right circularly polarized light and left circularly polarized light was equal to the FWHM (Full Width at Half Maximum) of the saturated absorption peak, the laser frequency was stabilized best.
在存在磁场的情况下，中性原子的超精细能级结构会发生塞曼分裂。此外，原子被右旋圆偏振光和左旋圆偏振光激发时，遵循不同的跃迁规则。因此，超精细塞曼能级之间的吸收峰相对于无磁场时的吸收峰发生偏移。相应地，作者展示了一种简单灵活的方法来稳定二极管激光器的频率。使用该方法，二极管激光器的线宽降低到了1 MHz以下。通过分析实验结果，作者发现当右旋圆偏振光和左旋圆偏振光激发的原子超精细能级的两种偏移之和等于饱和吸收峰的半高宽（FWHM）时，激光频率的稳定效果最佳。
