Zullo R, Giorgini A, Avino S, Malara P, De Natale P, Gagliardi G
Opt Lett. 2016 Feb 1;41(3):650-2. doi: 10.1364/OL.41.000650.
We present a simple and effective method for frequency locking a laser source to a free-space-coupled whispering-gallery-mode cavity. The scheme relies on the interference of spatial modes contained in the light scattered by the cavity, where low- and high-order modes are simultaneously excited. A dispersion-shaped signal proportional to the imaginary component of the resonant optical field is simply generated by spatial filtering of the scattered light. Locking of a diode laser to the equatorial modes of a liquid droplet resonator is demonstrated using this scheme, and its performance is compared to the Pound-Drever-Hall technique. This new approach makes laser-frequency locking straightforward and shows a number of advantages, including robustness, low cost, and no need for sophisticated optical and electronic components.
我们提出了一种简单有效的方法，用于将激光源频率锁定到自由空间耦合的回音壁模式腔。该方案依赖于腔内散射光中包含的空间模式的干涉，其中低阶和高阶模式同时被激发。通过对散射光进行空间滤波，简单地生成了一个与谐振光场虚部成正比的色散形状信号。利用该方案演示了二极管激光器与液滴谐振器赤道模式的锁定，并将其性能与庞德-德瑞弗-霍尔技术进行了比较。这种新方法使激光频率锁定变得直接，并显示出许多优点，包括鲁棒性、低成本以及无需复杂的光学和电子元件。
