不同波长的激光器通过法布里-珀罗腔相对于铯原子谱线的锁定

Locking Multiple Wavelength Lasers to the Transition of Cesium Atoms by Using a Fabry-Pérot Transfer Cavity

采用共焦法布里珀罗腔(CFP)作为桥梁,可以实现不在原子、分子跃迁线附近的单频激光器相对于原子、分子跃迁线的锁定,从而可以有效地抑制激光频率的漂移。在实验中通过射频频率调制光谱技术结合饱和吸收光谱(SAS)将自制852nm光栅外腔反馈半导体激光器锁定到铯6S1/2Fg=4-6P3/2Fe=4、5交叉线上,通过Pound-Drever-Hall(PDH)射频边带技术将作为桥梁的共焦法布里珀罗腔锁定在852nm激光频率上。再通过PDH方法将830nm和908nm两台远离铯原子D2线的外腔半导体激光器同时锁定在作为桥梁的共焦法布里珀罗腔上,实现了830nm和908nm两台激光器相对于铯原子跃迁线的锁定。由锁定后的误差信号估算,20s内852nm激光器相对于铯原子Fg=4-Fe=4、5交叉线的频率起伏小于±540kHz,830nm、908nm激光器相对于共焦法布里珀罗腔的频率起伏分别小于±340kHz和±60kHz,共焦法布里珀罗腔相对于852nm激光的频率起伏小于±550kHz。

With a confocal Fabry-Pérot （CFP） cavity as a transfer cavity, the single-frequency laser can be stabilized to atomic or molecular lines when no atomic or molecular reference lines are available. In the experiment a CFP cavity as the transfer cavity is locked to homemade 852 nm grating-external-cavity diode laser whose frequency is stabilized to 6S1/2 Fg = 4 -6P3/2 Fe = 5 transition of cesium atom via RF frequency-modulation spectrum and saturated absorption spectrum. The frequencies of external-cavity diode lasers at 908 nm and 830 nm are locked to the stabilized transfer cavity via Pound-Drever-Hall RF sideband technique, and thus stabilized with respect to the transition of cesium atom. Estimated from the locked error signals, the corresponding frequency jitters of diode lasers at 852 nm, 830 nm and 908 nm are less than ±540 kHz, ±340 kHz and ±60 kHz in 20 s, respectively; while the frequency fluctuation of the CFP cavity to the 852 nm laser is in ±550 kHz.