The protocols for the control and readout of Nitrogen Vacancy (NV) centres electron spins in diamond offer an advanced platform for quantum computation, metrology and sensing. These protocols are based on the optical readout of photons emitted from N
V centres, which process is limited by the yield of photons collection. Here we report on a novel principle for the detection of NV centres magnetic resonance in diamond by directly monitoring spin-preserving electron transitions through measurement of NV centre related photocurrent. The demonstrated direct detection technique offers a sensitive way for the readout of diamond NV sensors and diamond quantum devices on diamond chips. The Photocurrent Detection of Magnetic Resonance (PDMR) scheme is based on the detection of charge carriers promoted to the conduction band of diamond by the two-photon ionization of NV- centres. Optical detection of magnetic resonance (ODMR) and PDMR are compared, by performing both measurements simultaneously. The minima detected in the measured photocurrent at resonant microwave frequencies are attributed to the spin-dependent occupation probability of the NV- ground state, originating from spin-selective non-radiative transitions.
