Nuclear spins nearby nitrogen-vacancy (NV) centers in diamond are excellent quantum memory for quantum computing and quantum sensing, but are difficult to be initialized due to their weak interactions with the environment. Here we propose and demonstrate a magnetic-field-independent, deterministic and highly efficient polarization scheme by introducing chopped laser pulses into the double-resonance initialization method. With this method, we demonstrate initialization of single-nuclear-spin approaching 98.1% and a 14N-13C double-nuclear-spin system approaching 96.8% at room temperature. The initialization is limited by a nuclear-spin depolarization effect due to chopped laser excitation. Our approach could be extended to NV systems with more nuclear spins and would be a useful tool in future applications such as nano-MRI and single-cell NMR.
@article{arxiv.1806.05881,
title = {Dynamically Polarizing Spin Register of NV Centers in Diamond using Chopped Laser Pulses},
author = {Nanyang Xu and Yu Tian and Bing Chen and Jianpei Geng and Xiaoxiong He and Ya Wang and Jiangfeng Du},
journal= {arXiv preprint arXiv:1806.05881},
year = {2019}
}