Determination of the Three-Dimensional Magnetic Field Vector Orientation with Nitrogen Vacany Centers in Diamond

At a Glance

Metadata	Details
Publication Date	2020-03-17
Journal	Nano Letters
Authors	Timo Weggler, Christian Ganslmayer, Florian Frank, Tobias Eilert, Fedor Jelezko
Institutions	Universität Ulm, Center for Integrated Quantum Science and Technology
Citations	33
Analysis	Full AI Review Included

6CCVD Technical Documentation & Analysis: 3D Magnetic Field Vector Orientation with NV Centers in Diamond

This documentation analyzes the key technical requirements and outcomes of the research paper, “Determination of the 3D Magnetic Field Vector Orientation with NV Centers in Diamond,” highlighting how 6CCVD’s expertise in customized MPCVD diamond solutions enables the replication and advancement of this quantum sensing technology.

Executive Summary

This paper successfully demonstrates a robust method for high-precision 3D static magnetic field vector reconstruction using isolated Nitrogen Vacancy (NV) centers in diamond, vital for quantum computing and magnetometry.

Application: Determination of the full 3D magnetic field vector orientation (polar and azimuthal angles) using single NV centers.
Core Material Requirement: Electronic grade, ultra-low impurity SCD with high ¹²C enrichment to maximize coherence and spin properties.
Methodology: Combination of photoluminescence (PL) anisotropy measurements and pulsed Optically Detected Magnetic Resonance (ODMR).
Key Achievement: Breaking the C_3v symmetry limitation by measuring tilt angles ($\theta$) across three different NV orientations, achieving vector precision < 0.4°.
Material Design: Diamond sample prepared with a specific (100) surface orientation and laser-cut to a height of 35 µm, demonstrating the need for custom, highly engineered substrates.
Relevance to 6CCVD: The experiment demands material specifications (purity, dimensions, surface quality, isotopic enrichment) that align precisely with 6CCVD’s advanced MPCVD single-crystal diamond (SCD) capabilities.

Technical Specifications

The following key operational and material parameters were extracted from the research for the 3D magnetometry experiment:

Parameter	Value	Unit	Context
Diamond Material	SCD (Electronic Grade)	N/A	High-purity single crystal diamond (Element Six source)
Surface Orientation	(100)	N/A	Specified cut direction for lattice structure analysis
Substrate Height	35	µm	Precision laser cut and polishing requirement
Nitrogen Impurity (N_s)	< 5	ppb	Requirement for electronic/quantum grade diamond
Boron Impurity (B)	< 1	ppb	Requirement for electronic/quantum grade diamond
CVD Layer Composition	¹²C Enriched	N/A	Grown layer for improved NV center coherence
Nitrogen Implantation Energy	5	keV	Used to create near-surface NV centers
**Applied Magnetic Field (	B	)**	~ 230
Zero Field Splitting (D)	2870	MHz	NV transition frequency (approximate)
Rabi Period ($\Omega$)	1.58	µs	Typical value used during $\pi$-pulse measurements
B-field Vector Accuracy	< 0.4	°	Overall angular error interval for 3D reconstruction
Excitation Wavelength ($\lambda$)	519	nm	Pulsed laser used for NV excitation (ODMR readout)

Key Methodologies

The experiment relies on precision material engineering, advanced defect creation, and highly controlled optical and microwave instrumentation.

Diamond Substrate Engineering:
- Starting with electronic-grade SCD, the substrate was laser cut and polished to a precise 35 µm height with a (100) surface orientation.
- A high-purity, isotopically enriched ¹²C layer was grown via CVD on the polished surface to maximize coherence time (T₂).
NV Defect Creation:
- Nitrogen implantation was performed at 5 keV energy into the ¹²C enriched layer, followed by annealing (not explicitly detailed, but implied by NV formation) to create the NV centers.
Confocal Microscopy and Optical Readout:
- A home-built confocal microscope, equipped with a high N.A. objective (1.45), was used for optical detection and manipulation of single NV centers.
- A 519 nm pulsed laser system was used for excitation, with NV fluorescence detected through a 635 nm long-pass filter by a single photon counting module.
Microwave (MW) Manipulation:
- MW pulses were generated by an arbitrary waveform generator (AWG) and delivered via a 25 µm copper wire antenna spanned across the diamond surface.
- The pulsed ODMR scheme involved a $\pi$-pulse (MW) followed by a gated laser pulse (optical readout) to measure the |0> $\leftrightarrow$ |±1> transitions.
3D Vector Reconstruction:
- The tilt angles ($\theta_{i}$) relative to the four tetrahedral NV axes were determined via ODMR frequency splitting measurements.
- The B-field vector was calculated by solving a system of linear equations derived from the intersection of the B-field cones (formed by the measured tilt angles $\theta_{i}$).

6CCVD Solutions & Capabilities

This research demonstrates a clear demand for highly customized, ultra-high-purity single-crystal diamond materials. 6CCVD is uniquely positioned to supply the foundational materials necessary to replicate and scale this precise quantum sensing technique.

Applicable Materials

To achieve the narrow linewidth and long coherence times required for high-accuracy magnetometry (error < 0.4°), researchers need materials with minimal internal strain and foreign impurity atoms.

6CCVD Material Solution	Specification & Benefit	Application Relevance
Quantum Grade SCD	SCD wafers grown with N < 1 ppb. Guaranteed high crystal quality (Ra < 1 nm polished).	Minimizes strain broadening and enhances the coherence time (T₂) of the NV centers, crucial for high-resolution ODMR.
Isotopically Purified ¹²C SCD	MPCVD growth of SCD layers with > 99.999% ¹²C enrichment.	Eliminates decoherence from ubiquitous ¹³C nuclear spins, maximizing the quantum sensitivity of the NV spin sensor.
Custom Polycrystalline Diamond (PCD)	SCD substrates up to 125mm with thickness up to 500µm; PCD substrates up to 10mm thickness.	Offers platform flexibility for integration into commercial nanoscopic sensor arrays or large-area quantum imaging systems.

Customization Potential

The experiment utilized a highly specialized 35 µm thick, (100)-oriented substrate. 6CCVD excels in providing these critical custom specifications:

Precision Substrate Dimensions: 6CCVD provides custom diamond plate/wafer dimensions up to 125mm (PCD) and precise thickness control for both SCD and PCD (from 0.1 µm to 500 µm). We can deliver the 35 µm thick (100) substrates required for this setup.
Atomic-Scale Polishing: We guarantee ultra-smooth SCD surfaces (Ra < 1 nm) necessary for minimizing surface strain effects and integrating high-N.A. immersion objectives.
Integrated Microwave Structures: The paper used an external copper wire antenna. 6CCVD offers in-house custom metalization services (Ti, Au, Pt, Cu, Pd, W) to directly fabricate microwave striplines or planar antennas (e.g., CPW structures) onto the diamond surface. This integration drastically improves MW delivery efficiency and allows for scalable device fabrication.

Engineering Support

6CCVD provides comprehensive technical support extending beyond material supply:

Defect Engineering Consultation: Our in-house PhD team can advise on optimal parameters for NV creation (implantation energy, annealing recipes) to ensure defects are positioned correctly within the high-purity CVD layer.
Material Selection for Quantum Projects: We offer authoritative consultation on material grade, isotopic purity, and surface preparation required for similar single spin-based quantum magnetometry, EPR, or NMR applications.

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

View Original Abstract

Absolute knowledge about the magnetic field orientation plays a crucial role in single spin-based quantum magnetometry and the application toward spin-based quantum computation. In this paper, we reconstruct the three-dimensional orientation of an arbitrary static magnetic field with individual nitrogen vacancy (NV) centers in diamond. We determine the polar and the azimuthal angle of the magnetic field orientation relative to the diamond lattice. Therefore, we use information from the photoluminescence anisotropy of the NV, together with a simple pulsed optically detected magnetic resonance experiment. Our nanoscopic magnetic field determination is generally applicable and does not rely on special prerequisites such as strongly coupled nuclear spins or particular controllable fields. Hence, our presented results open up new paths for precise NMR reconstructions and the modulation of the electron-electron spin interaction in EPR measurements by specifically tailored magnetic fields.

Tech Support

Original Source

DOI: https://doi.org/10.1021/acs.nanolett.9b04725