Fig. 1: Experimental setup and one-dimensional magnetic resonance tomography of NV centers.

a Electron micrograph of a device as used in the present study. Currents in the three gold wires of a microfabricated U-Structure create three linearly independent magnetic field gradients in the densely doped diamond below the structure. b Pulse sequence for one-dimensional imaging. A magnetic gradient pulse (length t_eff) inserted into a Hahn echo sequence phase-encodes position. The NV spin state is initialized and the spin projection \(\langle {\hat{S}}_{z}\rangle\) is read out optically. c Measurement result of (b). π/2_x and π/2_y denote the phase of the trailing π/2 pulse in (b). d Fourier transform of a dataset like (c) extending to t = 60 μs. Every NV center gives rise to one peak at the Larmor frequency set by the magnetic field \({B}_{{I}_{1}}(d)\) of the wire. d denotes the distance from the centroid of the NV center’s cluster (e) Experimental setup. A single microwave generator, a 90^∘ splitter and two microwave switches are used to implement the Hahn Echo sequence. A confocal microscope with an avalanche photodiode (APD) as a detector is used for NV center polarization and readout. The gradient currents I₁, I₂, I₃ are created from a constant voltage source and can be pulsed by a fast switch (ic-Haus HGP), which has a current rising and falling time of 1 ns. The voltage drop across the resistor is recorded by an A/D-converter and the pulse integral ∫ Idt is saved for every single current pulse.