Light-shift mitigation in a microcell-based atomic clock with Symmetric Auto-Balanced Ramsey spectroscopy

TL;DR

This paper demonstrates that symmetric Auto-Balanced Ramsey spectroscopy significantly reduces light-shift effects in microcell atomic clocks, improving their stability and performance for timekeeping applications.

Contribution

The implementation of SABR interrogation in microcell atomic clocks offers a novel approach to mitigate light-shift effects, enhancing clock stability over a wide range of integration times.

Findings

Sensitivity to laser and microwave power variations is reduced by over an order of magnitude.

Light-shift mitigation improves the clock's Allan deviation for 10^2 to 10^5 seconds.

SABR technique enhances the performance of chip-scale atomic clocks.

Abstract

The mid-term fractional frequency stability of miniaturized atomic clocks can be limited by light-shift effects. In this Letter, we demonstrate the implementation of a symmetric Auto-Balanced Ramsey (SABR) interrogation sequence in a microcell-based atomic clock based on coherent population trapping (CPT). Using this advanced protocol, the sensitivity of the clock frequency to laser power, microwave power and laser frequency variations is reduced, at least by one order of magnitude, in comparison with continuous-wave (CW) or Ramsey interrogation schemes. Light-shift mitigation obtained with the SABR sequence benefits greatly to the clock Allan deviation for integration times between 10$^2$ and 10$^5$ s. These results demonstrate that such interrogation techniques are of interest to enhance timekeeping performances of chip-scale atomic clocks.