P Schwindt, Svenja A. Knappe, V Shah, Leo W. Hollberg, John E. Kitching, Li-Anne Liew, John Moreland
Using the techniques of micro-electro-mechanical systems (MEMS), we have constructed a small, low-power magnetic sensor based on alkali atoms. By measuring the energy shift of the atoms' magnetic moment due to a magnetic field via a coherent population trapping resonance, we detect the magnetic flux density with a sensitivity of 50 pT Hz-1/2 at 10 Hz. The magnetic sensor has a size of 12 mm3 and dissipates 195 mW of power. Further improvements in size, power dissipation, and magnetic field sensitivity are immediately foreseeable, and such a device could provide a hand-held, battery-operated magnetometer with an atom shot-noise limited sensitivity of 0.05 pT Hz-1/2.