Optically pumped quantum M_x–M_R magnetometer with high oscillating magnetic field

A dip of the transverse component of the magnetic moment as a function of resonance frequency-detuning will emerge when the intensity of oscillating magnetic field exceeds a specific value, which is demonstrated theoretically and experimentally. The linewidth of magnetic-resonance signal can be much smaller than when the M_x–M_R magnetometer operates on condition that the intensity of oscillating magnetic field is smaller than this specific value, and the M_x–M_R magnetometer can possess a much higher signal-to-noise ratio. The experimental result shows that the sensitivity of M_x–M_R magnetometer can be improved by an order of magnitude under this condition.