Light shift suppression with pulsed light detection in magnetic-state-selected cesium beam clocks

Light detection is widely used in atomic clocks. The simple detecting structure induces the light shift which influences the clock's long-term stability. We introduce a new method to suppress light shift by using pulsed light instead of continuous light to detect atomic states. Under a suitable pulsed sequence, the part of the atoms which do not simultaneously interact with light and microwave field are detected. We demonstrate the validity of our approach in a magnetic-state-selected cesium beam clock. Using a well-tuned sequence, the light shift coefficient is reduced by a factor of about 10, in comparison with the continuous light detection scheme. In a clock stability test with extra light power noise, the result shows good immunity of the method to laser power fluctuations. We also analyze the sources of the clock short-term stability degradation, including the Dick effect and the fact that a reduced number of atoms is detected in the pulsed detection case. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

The study introduces a new method to suppress light shift in atomic clocks by using pulsed light instead of continuous light for atomic state detection. Experimental results demonstrate the effectiveness of this method in a magnetic-state-selected cesium beam clock, with reduced light shift coefficient and good immunity to laser power fluctuations. The study also analyzes the reasons for the degradation of clock short-term stability.