Progress of the research on narrow-linewidth laser at 698 nm

REN Li-qing^1,2,3, LIU Jie^1,3, GAO Jing^1,3, ZHANG Lin-bo^1,4, JING Liang^1,4,

DONG Rui-fang^1,3, LIU Tao^1,3, LI Yong-fang², ZHANG Shou-gang^1,3

(1. National Time Service Centre, Chinese Academy of Sciences, Xi′an 710600, China;

2. School of Physics and Information Technology, Shaanxi Normal University, Xi′an 710062, China;

3. Key Laboratory of Time and Frequency Primary Standard, Chinese Academy of Sciences, Xi′an 710600, China;

4. Graduate University of Chinese Academy of Sciences, Beijing 100039, China)

Abstract: Narrow-linewidth laser plays an important role in Cs atomic fountain clock and optical clock as well as time and frequency transfer. We mainly introduce the progress of the research on narrow-linewidth laser at 698 nm in the National Time Service Centre. The two-steps stabilization for laser frequency is adopted to lock the laser on the pre-cavity and ultra-stable cavity in our experiment. Presently, the laser linewidth is around   1.1 kHz with the first stabilization, while the laser locking in the second stabilization is preliminarily achieved. A Hz-level laser is expected by gradually improving the second stabilization.

Key words: Sr optical lattice clock; narrow-linewidth laser; high-accuracy time and frequency; laser frequency stabilization