Photoelectrical imaging and coherent spin-state readout of single nitrogen-vacancy centers in diamond

Emilie Bourgeois, Michal Gulka, Daniel Wirtitsch +9 more

Petr Siyushev, Miloš Nesládek, Emilie Bourgeois +7 more

Nitrogen-vacancy (NV) centers in diamond have become an important instrument for quantum sensing and quantum information science. However, the readout of NV spin state requires bulky optical setups, limiting fabrication of miniaturized compact devices for practical use. Here we realized photoelectrical detection of magnetic resonance as well as Rabi oscillations on a single-defect level. Furthermore, photoelectrical imaging of individual NV centers at room temperature was demonstrated, surpassing conventional optical readout methods by providing high imaging contrast and signal-to-noise ratio. These results pave the way toward fully integrated quantum diamond devices.

Luke R. P. Hacquebard, Loutfi Kuret, Lilian Childress

Ilia Chuprina, Christoph Findler, Johannes Lang +2 more

Photoelectrical readout of the electronic spin state of the nitrogen-vacancy (NV) center in diamond is attracting significant interest due to the numerous advantages it possesses compared with conventional fluorescence readout. The higher charge carrier rate compared to the photon rate and the integration of the detection scheme on a chip can significantly advance quantum sensing and computing with color centers in diamond. Until now, photoelectric readout has been performed on ensembles of NV centers or single NV centers deep in ultrapure diamond substrates. However, many applications require the artificial creation and precise placement of shallow NV centers, and photoelectric detection of such centers has been challenging. Here we demonstrate photoelectrical readout and coherent control of the electronic spin of implanted shallow ($\sim$10 nm) NV centers buried by diamond overgrowth. The photoelectrically measured Ramsey $T_2^*$ agrees with conventional fluorescence readout and shows no measurable dependence on the readout photocurrent, for both shallow implanted and deep ingrown NV centers. We further find that overgrowth improves photoelectric readout by suppressing the background photocurrent. These results establish photoelectric readout as a viable route to chip-integrated, electrically detected nanoscale sensing and to spin registers based on engineered shallow NV centers.

Ilia Chuprina, Genko Genov, Christoph Findler +3 more

Nitrogen-vacancy (NV) centers in diamond are of great interest for nano- and macro-scale magnetic field sensing. Most sensing protocols rely on conventional optical readout, which is limited by photon shot noise. The recently developed photoelectrical (PE) readout of the NV center electron spin state promises to overcome these limitations. However, the noise of the PE readout and its influence on readout efficiency have not been thoroughly studied. In this work, we perform magnetic field sensing and estimate the sensitivity using optical and PE readout with a single and an ensemble of NV centers in diamond. We investigate the electronic noise associated with the photoelectric detection and estimate the readout efficiency, using Gaussian statistics. Our quantitative analysis shows that the Johnson-Nyquist noise-limited photoelectric magnetic field sensitivity could outperform optical measurements by an order of magnitude. This work is an essential step towards the development of on-chip magnetometers using photoelectrical detection in diamond.

Emilie Bourgeois, Michal Gulka, Miloš Nesládek

Abstract A novel method for reading out the electron spin state of the negatively charged nitrogen‐vacancy (NV) point defect in diamond, based on photoelectric detection of NV magnetic resonances (PDMR), is reviewed. As a convenient way to measure the spin state of qubits, the presented technique is anticipated to lead to a vast range of applications in the field of quantum technologies. It has been demonstrated that this method can be used both in continuous‐wave mode and for the pulse readout of coherently manipulated NV− spins. The PDMR technique presents interesting advantages over the commonly used optical detection of magnetic resonances (ODMR) and was recently downscaled to the reading out of a single NV− spin qubit. The principles, current developments, advantages, and drawbacks of PDMR are presented in this progress report. A complete to‐date methodology of NV photoelectric readout is described and PDMR is compared to ODMR. Future developments and possible improvements of the technique are mentioned. The results of the latest studies, aiming at overcoming limitations in the PDMR contrast through a better understanding of NV photo‐physics and of charge exchanges between NV centers and other electrically active defects, are discussed.