Magneto-optical detection of weak magnetic fields

Imaging modalities currently available for inexpensive imaging of biomagnetic fields are limited. Magneto-optical films have been used in magnetic field imaging systems with detection floors of 0.1-1 mT. A technique for magneto-optical detection of weak magnetic fields using bismuth-doped yttrium iron garnet (Bi:YIG) thin films is described. Results showing typical detected fields of 10 nT are presented. Such a device has potential clinical applications in MCG imaging and the tracking of magnetic particles.