Femtotesla atomic magnetometry in a microfabricated vapor cell
William C. Griffith, Svenja A. Knappe, John E. Kitching
We describe an optically pumped 87Rb magnetometer with 4.5 fT/Hz1/2 sensitivity when operated in the spin-exchange relaxation free (SERF) regime. The magnetometer uses a microfabricated vapor cell, consisting of a cavity etched in a 1 mm thick silicon wafer with anodically bonded pyrex windows. The measurement volume of the magnetometer is 1 mm3, defined by the overlap region of a circularly polarized pump laser, and a linearly polarized probe laser, both operated near 795 nm. Sensitivity limitations unique to the use of microfabricated cells are discussed.