Design of Magnetic Flux Concentrators for NV-Diamond Magnetoencephalography

Nitrogen-vacancy (NV) centers in diamond magnetometers are promising to be used for new magnetoencephalography (MEG) systems. However, the sensitivity of current NV magnetometers is limited for MEG signal detection. In this study, we demonstrate a novel magnetic flux concentrators (MFCs) design with trumpet and cut trumpet geometries for NV magnetometers, allowing MEG measurement. The sensitivity enhancement can be achieved 140 and 110-fold, and the field inhomogeneity can also be improved to 0.02% and 0.35% when using the trumpet and cut trumpet MFCs, respectively.