Effects of system parameters on single-beam synthetic gradiometer with dual-cell structure

• Wu ZiNan, Zhang Jialong, Chen Wei, Zhonghua Ou, Huimin Yue, cheng chunyue, and YONG LIU
• received 01/11/2024; accepted 04/13/2024; posted 04/18/2024; Doc. ID 518697
• Abstract: We report a single-beam synthetic gradiometer operated in the spin-exchange-relaxation free (SERF) regime, using the structure of two separate atomic vapor cells spaced 2cm apart. To improve the capability of the gradiometer in suppressing the common-mode magnetic field noise, we are aiming at investigating the effects of the system parameters on the gradiometer common-mode rejection ratio (CMRR). The mathematical expression for the relationship between the gradiometer CMRR and the two variables including the linewidth ratio and the pumping factor ratio are constructed for the first time. This means that the CMRR can be optimized by controlling the linewidth and the pumping factor, which is easy to implement in the operation process. As a result, a CMRR of 18.5 is achieved and a gradiometer sensitivity of 4.5fT/cm/Hz1/2 is also measured. This method is very useful for performance optimization of a gradiometer, which can be tuned to a desired state by simply controlling the linewidth and the incident light intensity.