A system for sensing magnetic fields is proposed, composed of an array of passive microfabricated alkali atom sensor heads coupled to a control unit using only optical interconnects. The optical coupling can be achieved by either free-space transmission of the interrogation and heating light, or through optical fiber links. The temperature of the sensor can be stabilized by monitoring the reflected or transmitted light power near DC while the magnetic field information is deduced simultaneously by detecting a modulation on the light power. A microfabricated sensor head, with a vapor cell of interior volume of 1 mm3 and fiber links connecting it to a control unit, is demonstrated experimentally. When operated in a scalar sensor mode in a field with a magnitude close to the earths field, a sensitivity of 3 pT/Hz1/2 was measured. In a low-field environment the sensor can be operated as a directional magnetometer with a sensitivity of 130 fT/Hz1/2. The design allows for arrays of a large number of small low-power sensors fabricated in an inexpensive way with widely variable sensor sizes and spacings.
Proceedings Title: Proceedings of the 2009 Conference on Lasers and Electro-Optics
Conference Dates: June 14-15, 2009
Conference Location: Baltimore, MD
Pub Type: Conferences
atomic magnetometer, MEMS, atomic spectroscopy, remote sensing