Self-contained fiber-coupled atomic magnetometers

Atomic magnetometers using a dense alkali-metal vapor have reached magnetic field sensitivities on the order of 200 aT/Hz$^{1/2}$, exceeding the sensitivity of best SQUID magnetometers.\footnote{H.B. Dang, A.C. Maloof, and M.V. Romalis, Appl. Phys. Lett. 97, 151110 (2010)} They are also relatively simple devices amenable to miniaturization and mass production. We are developing a fiber-coupled self-contained atomic magnetometer based on well-established fiber optic fabrication techniques. The magnetometer incorporates a Rb-Cs hybrid alkali-metal cell and a non-magnetic light polarization modulator for sensitive polarimetry. An array of such sensors can be used for magnetoencephalography and many other applications.