In Situ Calibration of Magnetic Coil System Using Ellipticity-Induced Bell-Bloom Magnetometer

The three-axis coil system is most commonly used in magnetic field measurement. The coil constant is an important parameter. We demonstrate a method to measure the coil constant based on the Larmor frequency. An elliptically polarized light is used to simultaneously excite the spin orientation and spin alignment via synchronous optical pumping. And then the coil system can be calibrated by measuring the magnetic resonance frequency of Bell-Bloom magnetometer. The advantage of this method is that the coil constants of all three directions can be obtained without any active adjustments. It is important for some applications, such as measuring the biological magnetic field with the integrated magnetometer. The method for calibration of a three-axis coil system is experimentally exploited. The experimental results show that the calibration accuracy of pT level can be achieved.