Magnetometry based on the effect of laser-induced plasmas in a sodium-containing environment

Abstract

The magneto-optical resonance response of sodium atoms generated by a high-energy solid-state pulse Nd:YAG laser is studied in different external magnetic fields. We investigate the resonance fluorescence signal of sodium atoms in a simulated sea fog environment based on the laser-induced plasma (LIP) effect. By ionizing an NaCl solution spray to generate sodium atoms in an atmospheric environment, we build a Bell–Bloom magneto-optical resonance system under laboratory conditions. With the help of laser-induced breakdown spectroscopy (LIBS) and extinction spectrum, we obtain sodium atoms with a lifetime of 250 µs. A narrowband tunable continuous wave (CW) 589-nm laser tuned at the D2 line with a modulation frequency around the Larmor frequency is used as the pump beam to polarize sodium atoms in the test magnetic field. We find that the magneto-optical resonance signals vary with different external magnetic fields and the positions of the resonance signal are consistent with the theoretical values. An intrinsic magnetometric sensitivity of 620.4 pT in a 1-Hz bandwidth is achieved.