对He-Ne双纵模激光器中两纵模的拍频稳定度进行了讨论。理论上分析了影响双纵模激光拍频稳定度的因素, 推导出在考虑了频率牵引效应后双纵模的拍频稳定度和单模频率稳定度之间的关系。计算结果表明对于632.8 nm波长的He-Ne激光器, 当频率牵引参量σi为10－3时, 双纵模的拍频稳定度约为其中任一单纵模频率稳定度的1000倍。实验证明当单纵模频率稳定度为1×10－9时, 其拍频稳定度为3.3×10－6。

The stability of beat frequency in the double-longitudinal-mode He-Ne laser is discussed. Considering the mode-pulling effect, the relation between the stability of the single mode and that of the beat frequency is deduced theoretically. The stability of the beat frequency in 632.8 nm He-Ne laser is 1000 times of that of the single mode with the frequency pulling parameter of 10-3. The experimental results show that the stability of the beat frequency is 3.3×10－6, when the single-mode stability reaches 1×10－9.