Dynamically Polarizing Spin Register of NV Centers in Diamond using Chopped Laser Pulses

TL;DR

This paper introduces a novel chopped laser pulse technique for highly efficient, magnetic-field-independent initialization of nuclear spins near NV centers in diamond, achieving near 98% polarization at room temperature.

Contribution

It presents a new polarization scheme using chopped laser pulses that significantly improves nuclear spin initialization efficiency in NV centers.

Findings

Achieved 98.1% polarization of single nuclear spins.

Demonstrated 96.8% polarization in a double-nuclear-spin system.

The method is effective at room temperature.

Abstract

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 $^{14}N$-$^{13}C$ 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.