Institute for Particle Physics and Astrophysics, ETH, 8093 Zurich, Switzerland.
Institut für Strahlwerkzeuge, Universität Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Deutschland.
Rev Sci Instrum. 2023 Jan 1;94(1):013001. doi: 10.1063/5.0130508.
The Pound-Drever-Hall (PDH) technique is a popular method for stabilizing the frequency of a laser to a stable optical resonator or, vice versa, the length of a resonator to the frequency of a stable laser. We propose a refinement of the technique yielding an "infinite" dynamic (capture) range so that a resonator is correctly locked to the seed frequency, even after large perturbations. The stable but off-resonant lock points (also called Trojan operating points), present in conventional PDH error signals, are removed by phase modulating the seed laser at a frequency corresponding to half the free spectral range of the resonator. We verify the robustness of our scheme experimentally by realizing an injection-seeded Yb:YAG thin-disk laser. We also give an analytical formulation of the PDH error signal for arbitrary modulation frequencies and discuss the parameter range for which our PDH locking scheme guarantees correct locking. Our scheme is simple as it does not require additional electronics apart from the standard PDH setup and is particularly suited to realize injection-seeded lasers and injection-seeded optical parametric oscillators.
磅-德雷弗-霍尔（PDH）技术是一种将激光频率稳定到稳定光学谐振器的流行方法，或者反之亦然，将谐振器的长度稳定到稳定激光的频率。我们提出了一种对该技术的改进，该技术产生了“无限”的动态（捕获）范围，从而即使在大干扰之后，谐振器也能正确锁定到种子频率。在传统的 PDH 误差信号中存在稳定但离谐的锁定点（也称为木马工作点），通过以对应于谐振器的自由光谱范围的一半的频率对种子激光进行相位调制，可以将其去除。我们通过实现注入锁定的 Yb：YAG 薄盘激光器来实验验证我们方案的鲁棒性。我们还给出了任意调制频率下 PDH 误差信号的解析公式，并讨论了我们的 PDH 锁定方案保证正确锁定的参数范围。我们的方案很简单，因为它不需要除标准 PDH 设置之外的额外电子设备，特别适合实现注入锁定的激光器和注入锁定的光学参量振荡器。
