High-frequency fibre-optic magnetometer with 70 fT/√(Hz) resolution

Using a cylindrical, DC field biased magnetostrictive transducer in a fibre-optic magnetometer we demonstrate 70 fT/√(Hz) resolution near 34 kHz. This represents 30 dB improvement over previous results. Resolution is limited by interferometric phase noise and is free from upconverted lowfrequency noise and residual signal effects.