Research Of578nm Frequency Stabilized Laser System With Narrow Linewidth

Narrow linewidth frequency stabilized lasers become crucial in the research of precision spectroscopy, development of cold atom/single ion optical clock, measurement of fundamental physics constants and tests of fundamental physics. A laser can be phase locked to the resonance of an ultra-stable optical cavity with high fineness using the Pound-Drever-Hall (PDH) technique in order to get the frequency stabilized laser with Hertz or even sub-Hertz linewidth.In this paper, we mainly research the578nm narrow linewidth laser system for probing the clock transition of Yb clock. Firstly, the578nm laser light is produced by the sum of1030nm fiber laser and1319nm YAG laser in a PPLN crystal, then we use PDH technique and an ultra-stable cavity with high finesse which is immune to vibration to provide the reference frequency. The frequency of578nm laser is precisely locked to reference cavity by controlling both PZT of1319nm YAG laser for slow servo and AOM for fast servo. To eliminate phase noise caused by random phase modulation of optical fiber which result in extra broaden spectrum, we research and improve the fiber noise cancellation system(FNCL) to ensure precise transfer of578nm narrow linewidth laser in the fiber.The beating was made between578nm narrow linewidth laser and the narrow linewidth optical frequency comb. The measurement results show the most probable linewidth of578nm laser is about1.18Hz, and its frequency stabilization is1.24×10-15(1s), which is close to the thermal noise limit of our system.