Photoelectric Detection and Quantum Readout of Nitrogen‐Vacancy Center Spin States in Diamond

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.

Long-Lived Ensembles of Shallow NV– Centers in Flat and Nanostructured Diamonds by Photoconversion

“…Laser irradiation can also induce a charge-state conversion, either by promoting an electron from the NV – excited state into the conduction band (NV – → NV 0 conversion) or by exciting an electron from the valence band to the NV 0 ground state (NV 0 → NV – conversion). 38 These two routes of photoconversion are represented by green dotted arrows. Experimental observations suggest that, upon switching off the laser, the system goes back to equilibrium through charge conversion in the dark, a process attributed to electron tunneling (black dotted arrows).…”

Carrier recombination and diffusion in high-purity diamond after electron irradiation and annealing

“…Large fraction of these defects shows up in the visible spectrum and has been utilized for color treatment of diamond specimens [Zaitsev 2017, Luhmann 2018. In recent years, evolution of the nitrogen-vacancy (NV) center has attracted significant interest for applications ranging from biolabeling to quantum computing due to its quantum optical properties [Bourgeois 2020].…”

Electrical readout microwave-free sensing with diamond

“…Under this condition, the NV centers in the effective photoelectric interrogation volume experience optimal optical excitation. When the laser spot passes through the electrode plane, the PC signal falls quickly due to less intense photoionization which is quadratically dependent on the laser intensity, and a rapidly decaying electric field [12]. The PL signal, however, experiences a different z-axial profile: it slightly increases from the level of 0.6 to 0.8 when the focal spot moves from -3 mm to -1 mm and then falls suddenly to a level of 70 % to the maximum.…”

“…The electrons from P1 centers can be promoted to the CB directly via one-photon ionization [Fig. 2 (a)] [5,12,16]. These generated charge carriers lead to a background photocurrent signal [Fig.…”

“…First, the electrical readout is compatible with nanoscale electrode structures [10], enabling advances towards integrated large-scale diamond quantum devices. It can be utilized to build scalable sensor arrays [12] and microscopes potentially superior to existing diamond quantum microscopes [25,26] in terms of resolution. Second, it can be used to build hybrid gradiometers taking advantage of the sensing volume mismatch of PC readout and PL detection.…”