Laser-based precision magnetometry in fundamental and applied research

In this paper we review research done by the recently founded Fribourg group for Atomic Physics (FRAP) using laser-assisted spin coherence spectroscopy of atomic samples in applied and fundamental physics. Spin coherence in optically pumped ensembles of paramagnetic atoms may be extremely long-lived when the samples are well shielded from external perturbations, like static or oscillating magnetic fields and field gradients, static electric fields, or crystalline field gradients. Conversely, such interactions may be studied with high sensitivity and precision when the decoherence that they produce is measured by optical means. We report on applications of this technique covering optical magnetometry for biomagnetic diagnostics, investigations of atomic impurities in quantum crystals, measurements of forbidden tensor polarizabilities and electric dipole moments, and the space-time resolved study of the diffusion of gas-phase atoms.