Simultaneous Broadband Vector Magnetometry Using Solid-State Spins

We demonstrate a vector magnetometer that simultaneously measures all Cartesian components of a dynamic magnetic field using an ensemble of nitrogen-vacancy (NV) centers in a single-crystal diamond. Optical NV-diamond measurements provide high-sensitivity, broadband magnetometry under ambient or extreme physical conditions and the fixed crystallographic axes inherent to this solid-state system enable vector sensing free from heading errors. In the present device, multichannel lock-in detection extracts the magnetic-field-dependent spin-resonance shifts of NVs oriented along all four tetrahedral diamond axes from the optical signal measured on a single detector. The sensor operates from near dc (5 Hz) up to a 12.5-kHz measurement bandwidth and simultaneously achieves approximately 50 pT/root Hz magnetic-field sensitivity for each Cartesian component, which is, to date, the highest demonstrated sensitivity of a full vector magnetometer employing solid-state spins. Compared to optimized devices interrogating the four NV orientations sequentially, the simultaneous vector magnetometer enables a 4x measurement speedup. This technique can be extended to pulsed-type sensing protocols and parallel wide-field magnetic imaging.