Measurements of Spatial Angles Using Diamond Nitrogen–Vacancy Center Optical Detection Magnetic Resonance

At a Glance

Metadata	Details
Publication Date	2024-04-19
Journal	Sensors
Authors	Zhenrong Shi, Haodong Jin, Hao Zhang, Zhonghao Li, Huanfei Wen
Institutions	North University of China
Citations	2
Analysis	Full AI Review Included

Technical Documentation & Analysis: Diamond NV Center Spatial Angle Measurement

This document analyzes the research paper “Measurements of Spatial Angles Using Diamond Nitrogen-Vacancy Center Optical Detection Magnetic Resonance” and outlines how 6CCVD’s advanced MPCVD diamond materials and customization capabilities directly support and enable the replication and scaling of this high-precision magnetic sensing technology.

Executive Summary

The research successfully demonstrates a solid-state, all-optical system for non-contact spatial angle measurement (yaw, pitch, and roll) utilizing the high-sensitivity magnetic detection capabilities of ensemble Nitrogen-Vacancy (NV) centers in diamond.

Core Value Proposition: Realization of a solid-state, all-optical, wide-field vector magnetic sensor capable of determining spatial angles of magnetic components.
Material Foundation: The system relies on a high-quality, (100) oriented CVD Single Crystal Diamond (SCD) plate ($5 \times 5 \times 0.5 \text{ mm}^3$) with an NV concentration of $\approx 1.5 \text{ ppm}$.
Methodology: Continuous Wave (CW) Optical Detection Magnetic Resonance (ODMR) combined with CCD magnetic microscope imaging to map the magnetic vector distribution.
Performance Metrics: Achieved high angular precision with measurement errors of $1^\circ$ for yaw angle and $1.5^\circ$ for pitch and roll angles.
Sensitivity: Calculated magnetic field sensitivity ($\eta$) was approximately $0.26 \text{ µT/Hz}^{1/2}$.
Application Potential: Provides a robust, miniaturizable method for angle detection in complex environments, particularly for encapsulated or concealed magnetic components.

Technical Specifications

The following hard data points were extracted from the experimental setup and results, highlighting the critical material and performance parameters.

Parameter	Value	Unit	Context
Diamond Material	(100) SCD	N/A	CVD Diamond Plate
Diamond Dimensions	$5 \times 5 \times 0.5$	mm³	Core sensing element size
NV Center Concentration	$\approx 1.5$	ppm	Ensemble NV density required for signal
Excitation Wavelength	532	nm	Laser polarization source
Microwave Scan Range	2.5 to 3.1	GHz	Frequency range for ODMR manipulation
Microwave Power Input	30	dBm	Power applied to the NV center
Bias Magnetic Field (B₀)	$\approx 2.84$	mT	Used to lift spin state degeneracy
Yaw Angle Error ($\alpha$)	$1.0$	°	System measurement accuracy
Pitch/Roll Angle Error ($\phi, \beta$)	$1.5$	°	System measurement accuracy
Magnetic Field Sensitivity ($\eta$)	$\approx 0.26$	µT/Hz^1/2	Calculated detection limit
CCD Resolution	$1920 \times 1080$	pixels	Imaging sensor resolution
Imaging Field Size	$960 \times 540$	µm²	Area captured by 10x objective
Polishing Requirement	Ra < 1nm	N/A	Implied requirement for high-NA optical system

Key Methodologies

The spatial angle detection relies on precise ODMR spectroscopy and high-resolution magnetic field imaging.

Laser Excitation and Polarization: A high-stability 532 nm laser is focused onto the diamond sensitive layer using a 10x, NA=0.25 objective lens to polarize the NV centers to the initial $m_s = 0$ state.
Bias Magnetic Field Application: A uniform bias magnetic field ($B_0 \approx 2.84 \text{ mT}$) is applied to the diamond’s central region to separate the degenerate $\pm 1$ resonance peaks, enabling vector magnetic field detection along the four NV axes.
Microwave Scanning: A microwave source and antenna system provide a highly uniform microwave field (30 dBm power) to manipulate the electron spin states. The frequency is scanned from 2.5 to 3.1 GHz with a 0.3 MHz step.
Fluorescence Collection and Imaging: Fluorescence signals (filtered above 650 nm) are collected by a CCD camera (1920x1080 pixels, 200 FPS) synchronized with the microwave scan. Each pixel acts as a miniature photodetector.
ODMR Spectrum Generation: The grayscale intensity of each pixel is correlated with the corresponding microwave frequency point to generate a complete ODMR spectrum for that spatial location.
Magnetic Field Calculation: Lorentz fitting is applied to the ODMR spectra to determine the peak resonance frequencies. These frequencies are used to calculate the projection of the external magnetic field ($B_1, B_2, B_3, B_4$) onto the four NV axes, yielding the full vector magnetic field components ($B_x, B_y, B_z$).
Angle Determination: Spatial angle information (yaw, pitch, roll) is deduced from the calculated magnetic vector distribution using magnetic field positioning algorithms.

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to supply the high-specification diamond materials required for advanced NV center magnetometry and angle sensing applications. Our expertise in MPCVD growth and precision processing ensures optimal performance for quantum sensing research.

Applicable Materials for Replication and Scaling

The research requires high-purity, low-strain Single Crystal Diamond (SCD) with controlled nitrogen incorporation.

6CCVD Material Solution	Specification & Relevance to Research
Optical Grade Single Crystal Diamond (SCD)	Replication: We supply high-purity, low-strain (100) SCD wafers essential for maximizing NV center coherence time and signal contrast.
Controlled Nitrogen Doping	Optimization: The paper used $\approx 1.5 \text{ ppm}$ NV concentration. 6CCVD offers precise control over nitrogen incorporation during MPCVD growth, allowing researchers to optimize the ensemble density for maximum sensitivity ($\eta$) or spatial resolution.
Precision Polished Wafers	Optical Quality: The ODMR system relies on focusing a 532 nm laser and collecting fluorescence. 6CCVD guarantees surface roughness (Ra) < 1nm on SCD, minimizing scattering losses and maximizing signal-to-noise ratio (SNR).

Customization Potential for Advanced Systems

To extend this research into commercial or next-generation devices, 6CCVD offers critical customization services:

Customization Service	Relevance to NV Magnetometry	6CCVD Capability
Custom Dimensions & Thickness	The paper used $5 \times 5 \text{ mm}$ plates. We can supply custom SCD plates up to $10 \times 10 \text{ mm}$ or large-area Polycrystalline Diamond (PCD) wafers up to 125mm for wide-field imaging expansion.	Plates/Wafers: SCD (0.1µm - 500µm), Substrates (up to 10mm).
Integrated Microwave Structures	For enhanced ODMR, on-chip microwave antennas are often required.	Metalization: We offer internal deposition of Au, Pt, Pd, Ti, W, and Cu stacks, enabling integrated microstrip lines or coplanar waveguides directly on the diamond surface.
Boron Doped Diamond (BDD)	While not used in this paper, BDD is critical for electrochemical sensing applications often paired with NV centers.	Materials: We supply highly conductive BDD films for integrated sensor platforms.
Precision Laser Cutting	For complex geometries required for integration into micro-optical systems or displacement stages.	Processing: Custom laser cutting and shaping services to meet exact mechanical tolerances.

Engineering Support

6CCVD’s in-house PhD team specializes in the material science of quantum defects. We provide expert consultation to researchers and engineers working on similar Diamond NV Center Magnetic Sensing projects.

Material Selection: Assistance in selecting the optimal crystal orientation ((100) vs. (111)) and nitrogen concentration for specific sensitivity or spatial resolution targets.
Surface Preparation: Guidance on achieving the necessary surface termination and roughness for high-NA objective coupling and minimizing decoherence effects.
Global Logistics: Global shipping is handled efficiently (DDU default, DDP available) to ensure rapid delivery of critical materials worldwide.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

This article introduces a spatial angle measuring device based on ensemble diamond nitrogen-vacancy (NV) center optical detection magnetic resonance (ODMR). This device realizes solid-state all-optical wide-field vector magnetic field measurements for solving the angles of magnetic components in space. The system uses diamond NV center magnetic microscope imaging to obtain magnetic vector distribution and calculates the spatial angles of magnetic components based on the magnetic vector distribution. Utilizing magnetism for angle measuring enables non-contact measuring, reduces the impact on the object being measured, and ensures measurement precision and accuracy. Finally, the accuracy of the system is verified by comparing the measurement results with the set values of the angle displacement platform. The results show that the measurement error of the yaw angle of the system is 1°, and the pitch angle and roll angle are 1.5°. The experimental results are in good agreement with the expected results.

Tech Support

Original Source

DOI: https://doi.org/10.3390/s24082613

References

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