Figure 6
(a) Bx suppression factors at various temperatures. The suppression factors describe the co-magnetometer ability to suppress magnetic field noise. A smaller suppression factor indicates that the magnetic field is better suppressed by the co-magnetometer. The suppression factors can be fitted to the theoretical results. The suppression factors are better when the temperature of the vapour cell is higher. (b) The Rb polarization changes with the cell temperature while the pumping power density is 1.3 V. When the temperature is optimized, the polarization of Rb atoms is also measured to confirm that the polarization of Rb atoms is approximately 50%. As the number density of Rb atoms changes from 4.0 × 1014 cm−3 to 7.5 × 1014 cm−3, the polarization of Rb changes from approximately 0.6 to 0.4. This result shows that the polarization of Rb is approximately 50%. The co-magnetometer responses to rotations are almost largest. (c) The decays of the coupled spin ensembles to the step magnetic field By for different compensating fields Bz. These results are used to get Bn and Be to fit the suppression factor curve in Fig. 6(a). We tune Bz. The spins decay most rapidly if Bz is equal to −Bn. At the self-compensation point, Bz is equal to −Bn − Be. The slow decay in this figure shows the co-magnetometer response to the step magnetic field By at the self-compensation point.
