Research on methods for weak signal detection of atomic magnetometers

Atomic magnetometers use the coherent precession of polarized atomic spins to detect and measure magnetic fields. When an off-resonant, linearly polarized probe beam propagates through the atomic vapor cell, the precession will cause a rotation of its polarization plane. Measuring the angle of the rotation, the magnetic field can be calculated. In this paper, we introduce the basic principles of atomic magnetometers and describe the method to measure the angle. Then a dual-phase lock-in amplifier (LIA) is proposed to detect the weak signal of the atomic magnetometer. And we design a simulation for the LIA based on Matlab/Simulink. Our theoretical analysis and simulation results show that the detecting system is well working and it is possible to detect weak signal of magnetic fields in an accurate way.