Highly selective detection of individual nuclear spins using the rotary echo on an electron spin as a probe

TL;DR

This paper introduces a method using rotary echo on an electron spin to selectively detect individual nuclear spins with high precision, significantly narrowing resonance widths and improving detection specificity.

Contribution

The authors propose a novel rotary echo technique that enhances selectivity in nuclear spin detection by synchronizing phase switching with nuclear precession, allowing adjustable and much narrower resonances.

Findings

Resonance width can be decreased by increasing driving strength.

Method achieves 10-100 times narrower resonance compared to existing techniques.

Numerical simulations confirm the analytical predictions of improved selectivity.

Abstract

We consider an electronic spin, such as a nitrogen-vacancy (NV) center in diamond, weakly coupled to a large number (bath) of nuclear spins, and subjected to the Rabi driving with a periodically alternating phase (multiple rotary echo). We show that by switching the driving phase synchronously with the precession of a given nuclear spin, the interaction to this spin is selectively enhanced, while the rest of the bath remains decoupled. The enhancement is of resonant character. The key feature of the suggested scheme is that the width of the resonance is adjustable, and can be greatly decreased by increasing the driving strength. Thus, the resonance can be significantly narrowed, by a factor of 10--100 in comparison with the existing detection methods. Significant improvement in selectivity is explained analytically and confirmed by direct numerical many-spin simulations. The method can be applied to a wide range of solid-state systems.