Dynamical Decoupling of a single electron spin at room temperature

TL;DR

This paper demonstrates that dynamical decoupling via CPMG pulse sequences significantly extends the coherence time of a single electron spin at room temperature, enhancing magnetic field detection sensitivity.

Contribution

It shows that CPMG pulse sequences can prolong the coherence time of NV centers in diamond at room temperature, reaching up to 2.44 ms, and improves magnetic sensing sensitivity.

Findings

CPMG extends T2 to 2.44 ms in bulk diamond

No significant T2 increase observed in nanodiamonds

Magnetic field sensitivity improves by about two times with CPMG

Abstract

Here we report the increase of the coherence time T$_2$ of a single electron spin at room temperature by using dynamical decoupling. We show that the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence can prolong the T$_2$ of a single Nitrogen-Vacancy center in diamond up to 2.44 ms compared to the Hahn echo measurement where T$_2 = 390 \mu$s. Moreover, by performing spin locking experiments we demonstrate that with CPMG the maximum possible $T_2$ is reached. On the other hand, we do not observe strong increase of the coherence time in nanodiamonds, possibly due to the short spin lattice relaxation time $T_1=100 \mu$s (compared to T$_1$ = 5.93 ms in bulk). An application for detecting low magnetic field is demonstrated, where we show that the sensitivity using the CPMG method is improved by about a factor of two compared to the Hahn echo method.