Recursive polarization of nuclear spins in diamond at arbitrary magnetic fields

TL;DR

This paper presents a new method to polarize nuclear spins in diamond using recursive spin transfer techniques, achieving high polarization at any magnetic field without relying on level anti-crossings.

Contribution

The authors introduce a versatile recursive polarization method that works at arbitrary magnetic fields, unlike previous schemes dependent on level anti-crossings.

Findings

Achieved up to 80% nuclear spin polarization at room temperature.

Applicable to both ensemble and single NV centers.

Does not require specific magnetic field conditions.

Abstract

We introduce an alternate route to dynamically polarize the nuclear spin host of nitrogen-vacancy (NV) centers in diamond. Our approach articulates optical, microwave and radio-frequency pulses to recursively transfer spin polarization from the NV electronic spin. Using two complementary variants of the same underlying principle, we demonstrate nitrogen nuclear spin initialization approaching 80% at room temperature both in ensemble and single NV centers. Unlike existing schemes, our approach does not rely on level anti-crossings and is thus applicable at arbitrary magnetic fields. This versatility should prove useful in applications ranging from nanoscale metrology to sensitivity-enhanced NMR.