Vector magneto-optical magnetometer based on resonant all-dielectric gratings with highly anisotropic iron garnet films

Sensitive vector magnetometry with high spatial resolution is important for various practical applications, such as magnetocardiography, magnetoencephalography, explosive materials detection and many others. We propose a magnetometer based on magnetic iron garnet film possessing a very high magnetic anisotropy, placed in a rotating external magnetic field. Each of the measured magnetic field spatial components produces different temporal harmonics in the out-of-plane magnetization dependence. Our analysis based on numerical simulation shows that the dielectric resonant grating placed on the top of an ultrathin film enhanced the magneto-optical (MO) response by ten times. It allows one to reduce the thickness of the film, which makes it possible to achieve several times higher spatial resolution in the perpendicular to the film direction, up to 30 nm. The reported MO magnetometer allows one to measure simultaneously all three spatial components of the magnetic field with high spatial resolution and sensitivity up to 100 pT Hz^-1/2. (paper)