We experimentally investigate the protection of electron spin coherence of nitrogen vacancy (NV) center in diamond by dynamical nuclear polarization. The electron spin decoherence of an NV center is caused by the magnetic ield fluctuation of the 13C nuclear spin bath, which contributes large thermal fluctuation to the center electron spin when it is in equilibrium state at room temperature. To address this issue, we continuously transfer the angular momentum from electron spin to nuclear spins, and pump the nuclear spin bath to a polarized state under Hartman-Hahn condition. The bath polarization effect is verified by the observation of prolongation of the electron spin coherence time (T2∗). Optimal conditions for the dynamical nuclear polarization (DNP) process, including the pumping pulse duration and depolarization effect of laser pulses, are studied. Our experimental results provide strong support for quantum information processing and quantum simulation using polarized nuclear spin bath in solid state systems.
@article{arxiv.1305.6424,
title = {Protection of center-spin coherence by dynamically polarizing nuclear spin core in diamond},
author = {Gang-Qin Liu and Qian-Qing Jiang and Yan-Chun Chang and Dong-Qi Liu and Wu-Xia Li and Chang-Zhi Gu and Hoi Chun Po and Wen-Xian Zhang and Nan Zhao and Xin-Yu Pan},
journal= {arXiv preprint arXiv:1305.6424},
year = {2015}
}