Laser-pumped cesium magnetometers for high-resolution medical and fundamental research

Laser-pumped cesium magnetometers allow highly sensitive magnetometry at room temperature. We report on applications of that technique in biomagnetic diagnostics and in a neutron electric dipole moment (nEDM) experiment. In the biomagnetic application the magnetic field from the beating human heart is detected using a gradiometer, which reaches an intrinsic sensitivity of 80 fT/Hz1/2. The device can record time-resolved magnetic field maps above the human body surface with a spatial resolution of 4 cm and its performance is comparable to commercial devices based on the SQUID technique. In the nEDM experiment laser-pumped cesium magnetometers are used to measure and stabilize a dc magnetic field at a level of 10−7. Those devices reach an intrinsic sensitivity of about 14 fT/Hz1/2 with a measurement bandwidth of 1 kHz. The general principle of operation and specific results are presented.