为了降低超稳光学腔的振动敏感度, 在综合考虑振动所导致的腔镜位移及转动后, 定义了一个新的表征腔体振动敏感度的参量。采用有限元数值分析方法, 用所定义的单一参量优化了一个典型的立式超稳光学腔。优化过程考虑了腔体端面直径、支撑孔位置和深度等关键几何参量。结果表明, 优化后的腔体结构和支撑方式可以明显降低超稳腔对振动的敏感度, 腔体稳定性比优化前提高1.5倍。该优化方法操作性强, 能够有效提升超稳腔仿真和设计的效率。

A frequency-stabilized 556-nm laser is an essential tool for experimental studies associated with 1S0-3P1 intercombination transition of ytterbium (Yb) atoms. A 556-nm laser light using a single-pass second harmonic generation (SHG) is obtained in a periodically poled MgO:LiNbO3 (PPLN) crystal pumped by a fiber laser at 1111.6 nm. A robust frequency stabilization method which facilitates the control of laser frequency with an accuracy better than the natural linewidth (187 kHz) of the intercombination line is developed. The short-term frequency jitter is reduced to less than 100 kHz by locking the laser to a home-made reference cavity. A slow frequency drift is sensed by the 556-nm fluorescence signal of an Yb atomic beam excited by one probe beam and is reduced to less than 50-kHz by a computer-controlled servo system. The laser can be stably locked for more than 5 h. This frequency stabilization method can be extended to other alkaline-earth-like atoms with similar weak intercombination lines.

We build a Zeeman slower with consecutive coils and use it to load an Yb magneto-optical trap (MOTs). Cooling efficiency is measured by the fluorescence intensity of the atomic cloud trapped by the MOT. An optimized magnetic field profile can acquire the maximum cooling efficiency, corresponding to a good compromise between the smaller magnetic field mismatch and the high capture velocity. Our studies provide useful information on how the performance of the Zeeman slower can be improved.