High fidelity single-shot readout of qubits is crucial for fault-tolerant quantum computing and scalable quantum networks. The nitrogen-vacancy (NV) center in diamond is a leading platform, but current single-shot readout using resonance fluorescence is limited by spin-flip errors. This paper introduces a spin-to-charge conversion method assisted by near-infrared (NIR) light to suppress these errors, achieving >95% fidelity. This technique, leveraging spin-selective cryogenic resonance excitation and photo-ionization, has potential for exceeding fault-tolerant thresholds and applications in integrated optoelectronic devices.

Qi Zhang, Yuhang Guo, Wentao Ji, Mengqi Wang, Jun Yin, Fei Kong, Yiheng Lin, Chunming Yin, Fazhan Shi, Ya Wang, Jiangfeng Du