Fiber-optic polarimetric DC magnetometer utilizing a composite metallic glass resonator

A fiber-optic polarimetric dc magnetometer has been constructed from 50 m of high birefringence optical fiber. Magnetic fields are detected by the magnetostrictive response of a composite thin-shell resonator consisting of an acrylic tube, unannealed metallic glass ribbon, and a 20-m coil of high birefringence fiber. Quadrature is maintained with the phase tracking technique and optical common-mode rejection is utilized for noise reduction. The rms magnetometer noise corresponds to a minimum detectable magnetic field of 2.6 γ in the dc to 1-Hz bandwidth.