Suppression of spin bath and low-frequency noise for sub-MHz AC magnetometry based on double-dressed spin qubit in diamond

TL;DR

This paper introduces a novel AC magnetometry protocol using double-dressed spin qubits in diamond, effectively suppressing spin bath noise and enabling detection of weak signals below 1 MHz with high SNR.

Contribution

It presents a new dynamical decoupling technique with double-dressed states for enhanced low-frequency AC signal detection in diamond-based quantum sensors.

Findings

Achieved SNR up to 17 for weak AC signals below 1 MHz.

Demonstrated effective suppression of qubit-bath interactions.

Enabled sensitive detection of weakly coupled nuclear spins in low-field NMR.

Abstract

We experimentally demonstrate a protocol that effectively suppresses the qubit-bath interaction in diamond and enables detection of weak AC signals (below 1 MHz) with enhanced signal-to-noise ratio (SNR) up to SNR = 17. The method is based on AC magnetometry with single- and double-dressed states that are adiabatically transferred from the initial qubit states using concatenated continuous dynamical decoupling. This work paves a way toward sensitive detection of weakly coupled nuclear spins in low-field NMR experiments.