Robust all-optical single-shot readout of nitrogen-vacancy centers in diamond

Abstract

High-fidelity projective readout of a qubit’s state in a single experimental repetition is a prerequisite for various quantum protocols of sensing and computing. Achieving single-shot readout is challenging for solid-state qubits. For Nitrogen-Vacancy (NV) centers in diamond, it has been realized using nuclear memories or resonant excitation at cryogenic temperature. All of these existing approaches have stringent experimental demands. In particular, they require a high efficiency of photon collection, such as immersion optics or all-diamond micro-optics. For some of the most relevant applications, such as shallow implanted NV centers in a cryogenic environment, these tools are unavailable. Here we demonstrate an all-optical spin readout scheme that achieves single-shot fidelity even if photon collection is poor (delivering less than 103 clicks/second). The scheme is based on spin-dependent resonant excitation at cryogenic temperature combined with spin-to-charge conversion, mapping the fragile electron spin states to the stable charge states. We prove this technique to work on shallow implanted NV centers, as they are required for sensing and scalable NV-based quantum registers.

Highly tunable magneto-optical response from magnesium-vacancy color centers in diamond

“…Negatively charged nitrogen-vacancy center [NV(−)] in diamond represents the most studied defect qubit to date. However, the simple optical readout of the NV(−) spin state is inefficient, while an improvement over the signal-to-noise ratio requires specialist techniques [8][9][10] . Moreover, near-surface NV(−) centers (needed for quantum sensing) are unstable to the commonly used types of surface termination.…”

Diamond quantum sensors: from physics to applications on condensed matter research

“…The low readout fidelity was a big problem for sensing with the NV centre. Recently, a robust readout scheme based on the spin selective charge state switching has been demonstrated with fidelity above 95% [76,77]. These two new methods pave new directions of using the NV centre as a sensor.…”

Photoionization of negatively charged NV centers in diamond: theory and ab initio calculations

“…One important set of such experiments is spin-tocharge conversion upon dual-beam excitation at cryogenic temperatures [47,48]. In these protocols one narrow laser is used to resonantly excite NV − in a preselected spin state, e.g., m s = 0.…”

“…In order not to disturb other spin states, the photoionization is performed with sub-ZPL illumination. In the work of Irber et al efficient photoionization was obtained using a visible laser emitting at 642 nm (1.93 eV) [48]. At variance, Zhang et al used a NIR laser emitting at 1064 nm (1.17 eV) [47]; the overall scheme reached high spin readout fidelities, implying a rather effective photoionization.…”