A laser-pumped magnetometer for the mapping of human cardiomagnetic fields

Magnetic fields produced by biological organisms contain valuable information on the underlying physiological processes and their pathologies. Currently, superconducting detectors cooled far below room temperature are required to measure these generally weak biomagnetic signals. We have developed a sensitive laser magnetometer based on optical pumping of cesium atoms that makes it possible to map the magnetic field produced by the beating human heart. A gradiometer formed by two identical sensors greatly reduces the influence of external stray magnetic fields. The magnetometer operates at room temperature and therefore opens the way to affordable and convenient monitoring of biomagnetic fields in research and medical diagnostics.