Combined effect of light intensity and temperature on the magnetic resonance linewidth in alkali vapor cell with buffer gas**Project supported by the National Natural Science Foundation of China (Grant Nos. 51675034 and 61273067) and Beijing Natural Science Foundation (Grant No. 7172123).

Abstract

One of the peculiar phenomenons in non-zero magnetic resonance magnetometer is that, with the increase of the temperature, the magnetic resonance linewidth is narrowed at first instead of broadened due to the increasing collision rate. The magnetometer usually operates at the narrowest linewidth temperature to obtain the best sensitivity. Here, we explain this phenomenon quantitatively considering the nonlinear of the optical pumping in the cell and did experiments to verify this explanation. The magnetic resonance linewidth is measured using one amplitude-modulated pump laser and one continuous probe laser. The field is along the direction orthogonal to the plane of pump and probe beams. We change the temperature from 53 °C to 93 °C and the pumping light from 0.1 mW to 2 mW. The experimental results agree well with the theoretical calculations.