Highly sensitive macro-scale diamond magnetometer operated by dynamical decoupling sequence with coplanar waveguide resonator

TL;DR

This paper presents a highly sensitive macro-scale diamond magnetometer that uses a resonator-enhanced microwave field and dynamical decoupling sequences to significantly improve magnetic field detection sensitivity.

Contribution

The study introduces a novel microwave resonator and optical system to enhance sensitivity and coherence time in diamond-based quantum magnetometry.

Findings

Achieved 48 ns Rabi oscillation with strong microwave field

Extended spin coherence time (T2) by 27 times using XY16 sequence

Demonstrated magnetic field sensitivity of 10.8 pT/Hz$^{1/2}$

Abstract

Ultimate sensitivity for quantum magnetometry using nitrogen-vacancy (NV) centers in diamond is limited by number of NV centers and coherence time. Microwave irradiation with a high and homogeneous power density for a large detection volume is necessary to achieve highly sensitive magnetometer. Here, we demonstrate a microwave resonator to enhance the power density of the microwave field and an optical system with a detection volume of 1.4e-3 mm$^3$. The strong microwave field enables us to achieve 48 ns Rabi oscillation which is sufficiently faster than the phase relaxation time of NV centers. This system combined with a decoupling pulse sequence, XY16, extends the spin coherence time (T2) up to 27 times longer than that with a spin echo method. Consequently, we obtained an AC magnetic field sensitivity of 10.8 pT/Hz$^{1/2}$ using the dynamical decoupling pulse sequence.