Frequency Limits of Sequential Readout for Sensing AC Magnetic Fields Using Nitrogen-Vacancy Centers in Diamond

At a Glance

Metadata	Details
Publication Date	2023-08-31
Journal	Sensors
Authors	Santosh Ghimire, Seong-Joo Lee, Sangwon Oh, Jeong Hyun Shim
Institutions	Korea University of Science and Technology, Korea Research Institute of Standards and Science
Citations	4
Analysis	Full AI Review Included

Technical Documentation & Analysis: Frequency Limits of Sequential Readout for AC Magnetic Field Sensing

Executive Summary

This document analyzes the research on optimizing Nitrogen-Vacancy (NV) center magnetometry using Sequential Readout (SR) techniques, highlighting the critical role of high-quality CVD diamond materials.

Record Sensitivity: A maximum AC magnetic field sensitivity of 229 pT/√Hz was achieved at 1 MHz using an ensemble of NV centers in MPCVD diamond.
Methodology Validation: The study successfully employed the Sequential Readout (SR) scheme combined with the XY4-(4) Dynamical Decoupling (DD) sequence to achieve high-fidelity sensing in the kilohertz to megahertz range.
Frequency Limits Defined: The upper frequency limit is determined by the Rabi frequency (approx. 6.3 MHz), governed by the finite width of the pi pulses.
Repolarization Constraint: Crucially, the lower frequency limit (160 kHz) is shown to be governed by the duration of optical repolarization ($T_{Laser}$) rather than the intrinsic coherence time ($T_2$), especially when using NV ensembles below the saturation limit.
Material Requirements: The sensor utilized was a 40 µm thick, high-purity (¹²C > 99.99%), nitrogen-doped (10 ppm ¹⁴N) Single Crystal Diamond (SCD) layer grown by CVD.
Application Potential: These findings provide

View Original Abstract

The nitrogen-vacancy (NV) centers in diamond have the ability to sense alternating-current (AC) magnetic fields with high spatial resolution. However, the frequency range of AC sensing protocols based on dynamical decoupling (DD) sequences has not been thoroughly explored experimentally. In this work, we aimed to determine the sensitivity of the ac magnetic field as a function of frequency using the sequential readout method. The upper limit at high frequency is clearly determined by Rabi frequency, in line with the expected effect of finite DD-pulse width. In contrast, the lower frequency limit is primarily governed by the duration of optical repolarization rather than the decoherence time (T2) of NV spins. This becomes particularly crucial when the repetition (dwell) time of the sequential readout is fixed to maintain the acquisition bandwidth. The equation we provide successfully describes the tendency in the frequency dependence. In addition, at the near-optimal frequency of 1 MHz, we reached a maximum sensitivity of 229 pT/Hz by employing the XY4-(4) DD sequence.

Tech Support

Original Source

DOI: https://doi.org/10.3390/s23177566

References

2018 - High-resolution magnetic resonance spectroscopy using a solid-state spin sensor [Crossref]
2021 - Electromagnetic induction imaging with a scanning radio frequency atomic magnetometer [Crossref]
2017 - Prospects for magnetic field communications and location using quantum sensors [Crossref]
2008 - Nanoscale imaging magnetometry with diamond spins under ambient conditions [Crossref]
2008 - High-sensitivity diamond magnetometer with nanoscale resolution [Crossref]
2015 - Subpicotesla Diamond Magnetometry
2008 - Nanoscale magnetic sensing with an individual electronic spin in diamond [Crossref]
2008 - Scanning magnetic field microscope with a diamond single-spin sensor [Crossref]
2009 - Ultralong spin coherence time in isotopically engineered diamond [Crossref]
2008 - Far-field optical imaging and manipulation of individual spins with nanoscale resolution [Crossref]