Combined effect of light intensity and temperature on the magnetic resonance linewidth in alkali vapor cell with buffer gas

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.

Influence of pump intensity on atomic spin relaxation in a vapor cell*

“…[9][10][11] The spin relaxation in the vapor cell is affected by many factors, such as diffusion of atoms, [12,13] collision between atoms, [14][15][16] optical pumping, etc. The relaxation caused by diffusion and collision can be suppressed by some advanced techniques, such as atom-relaxation coating of the vapor cell, [17] optimizing the filling of buffer gas, [18] controlling the temperature of the vapor cell, [19] reducing the magnetic field gradient, [20] etc. The relaxation caused by optical pumping can be controlled by optimizing the pump intensity, [21] which is inevitable and cannot be eliminated completely.…”