Signal-enhanced spin-exchange relaxation-free atomic magnetometer

Spin-exchange relaxation-free (SERF) magnetometers have been widely used for weak magnetic field detection. With the advancement of integration technology, highly compact SERF atomic magnetometers have been used in noninvasive biomagnetic imaging and remarkable results have been achieved. We propose a highly sensitive reflective atomic magnetometer with a single beam. The polarization of the alkali-metal atoms is enhanced by reflecting circularly polarized light that passes through the vapor cell. The signal of the magnetic field is extracted by applying a high-frequency modulated magnetic field. Compared with the performance of the nonreflective magnetometer, the reflective magnetometer achieves a better sensitivity, up to 16 fT/Hz1/2 in the frequency range of 10–100 Hz and the response signal of the magnetometer is increased. The reflective magnetometer has characteristics of simple configuration, high precision, and easy miniaturization, which give it the potential to be applied in weak magnetic measurement, particularly in biomagnetic measurement research.