A robust method for performance evaluation of the vapor cell for magnetometry

Abstract

A robust performance evaluation method for vapor cells used in magnetometers is proposed in this work. The performance of the vapor cell determines the sensitivity of the magnetic measurement, which is the core parameter of a magnetometer. After establishing the relationship between intrinsic sensitivity and the total relaxation rate, the total relaxation rate of the vapor cell can be obtained to represent the intrinsic sensitivity of the magnetometer by fitting the parameters of the magnetic resonance experiments. The method for measurement of the total relaxation rate based on the magnetic resonance experiment proposed in this work is robust and insensitive to ambient noise. Experiments show that, compared with conventional sensitivity measurement, the total relaxation rate affected by magnetic noise below 0.9 nT, pump light frequency noise below 1.5 GHz, pump light power noise below 9%, probe light power noise below 3% and temperature fluctuation of 150 ± 3 °C deviates by less than 2% from the noise-free situation. This robust performance evaluation method for vapor cells is conducive to the construction of a multi-channel high-spatial-resolution cardio-encephalography system.