A chip-scale atomic magnetometer with improved sensitivity using the Mx technique
P Schwindt, Brad Lindseth, Svenja A. Knappe, V Shah, John E. Kitching, Li-Anne Liew
We discuss the fabrication and performance of a miniature optically pumped atomic magnetometer constructed using microfabricated components. This device measures the spin precession frequency of an alkali atom to determine the magnetic field using the Mx technique. It has a demonstrated sensitivity to magnetic fields of 5 pT / Hz1/2 between 1 and 100 Hz bandwidth, nearly an order of magnitude improvement over a previous chip-scale magnetometer. We have also increased the 3 dB bandwidth to 1 kHz by reconfiguring the miniature vapor cell heater to produce very little perturbing magnetic field. The magnetic sensor has a size of 25 mm3 and consumes 194 mW of power, and the potential for wafer-level fabrication and assembly of the components may result in low unit cost for mass-produced devices.