Fig. 4: Proposed experiment for vectorial magnetometry.

a Experimental setup, consisting of a typical confocal microscope with the possibility of applying a bias magnetic field in two different orientations. b Unit vectors indicating the orientations of B₁ and B₂, two 100 mT bias magnetic fields we use in this simulation, as well as the orientation of a 0.1-mT target magnetic field T with components T_x,y,z. c, d cwODMR spectra with B₁ and B₂, respectively. We monitor the change in contrast of each resonance due to the presence of the target magnetic field (shown explicitly in the inset) to gain information about each of its three vectorial components. e Ambiguity in determining the target magnetic field given a 1-second measurement of the contrast at the slope of each resonance. The grey arrow represents the target magnetic field. The clouds represent field configurations that cannot be distinguished from the target field under B₁ (light blue cylinder) and B₂ (pink dome).