Enhanced sensitivity in microscale high-field NMR via nuclear-spin locking with NV centers

Abstract

Solid state defects such as nitrogen vacancy (NV) centers in diamond have been utilized for NMR sensing at ambient temperatures for samples at the nano-scale and up to the micro-scale. Similar to standard NMR, NV-sensitivities can be increased using tesla-valued magnetic fields to boost nuclear thermal polarization, while structural parameters, such as chemical shifts, are also enhanced. However, with standard microwave (MW) based sensing techniques, NV centers struggle to track fast megahertz Larmor frequencies encountered in high-field scenarios. Previous protocols have addressed this by mapping target NMR parameters to the signal amplitude rather than the frequency, using a mediating RF field. Although successful, protocol sensitivities are limited by the coherence time ($T_2^{\ast }$) of the NMR signal owing to the presence of stages where the sample magnetization freely evolves. In this work, we propose extending this coherence time, and consequently improving sensitivity, via amplitude encoding with weak nuclear spin locking instead of free evolution, thereby taking advantage of the longer sample coherence times ($T_{1\rho }$). We demonstrate this can enhance protocol sensitivities by $\gtrsim 4$ times.

8 pages, 3 figures and Supplementary Information. This version incorporates referee suggestions after publication in Physical Review Applied

References in corpus (25)

• The nitrogen-vacancy colour centre in diamond
• Magnetometry with nitrogen-vacancy defects in diamond
• Sensitivity Optimization for NV-Diamond Magnetometry
• High Resolution Magnetic Resonance Spectroscopy Using Solid-State Spins
• Sub-millihertz magnetic spectroscopy with a nanoscale quantum sensor
• Atomic-scale imaging of a 27-nuclear-spin cluster using a single-spin quantum sensor
• Robust dynamical decoupling with concatenated continuous driving
• Sensing distant nuclear spins with a single electron spin
• Pulsed polarisation for robust DNP
• Quantum many-body theory for electron spin decoherence in nanoscale nuclear spin baths
• Single-molecule Scale Magnetic Resonance Spectroscopy using Nitrogen-Vacancy Centers in Diamond
• Imaging mesoscopic nuclear spin noise with a diamond magnetometer
• Hyperpolarization-enhanced NMR spectroscopy with femtomole sensitivity using quantum defects in diamond
• Atomic-scale nuclear spin imaging using quantum-assisted sensors in diamond
• Continuous dynamical decoupling magnetometry
• Micron-scale SABRE-enhanced NV-NMR Spectroscopy
• Mapping a 50-spin-qubit network through correlated sensing
• Nanoscale vector AC magnetometry with a single nitrogen-vacancy center in diamond
• High-Resolution NMR Spectroscopy at Large Fields with Nitrogen Vacancy Centers
• NV center based nano-NMR enhanced by deep learning
• Geometry dependence of micron-scale NMR signals on NV-diamond chips
• Modulated Continuous Wave Control for Energy-efficient Electron-nuclear Spin Coupling
• Robust Noise Suppression and Quantum Sensing by Continuous Phased Dynamical Decoupling
• Automatic Detection of Nuclear Spins at Arbitrary Magnetic Fields via Signal-to-Image AI Model
• Enhanced microscale NMR spectroscopy of low-gyromagnetic ratio nuclei via hydrogen transfer