AC sensing using nitrogen vacancy centers in a diamond anvil cell up ton 6 GPa
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-10-12 |
| Journal | arXiv (Cornell University) |
| Authors | Zhipan Wang, Christopher McPherson, R. Kadado, Nicholas Brandt, S. Edwards |
| Institutions | Planetary Science Institute, University of California, Davis |
| Citations | 8 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: AC Sensing in Diamond Anvil Cells
Section titled âTechnical Documentation & Analysis: AC Sensing in Diamond Anvil CellsâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates the use of Nitrogen-Vacancy (NV) centers in a Diamond Anvil Cell (DAC) for high-pressure AC magnetic sensing, a critical step toward performing all-optical Nuclear Magnetic Resonance (NMR) on nanoliter samples under extreme conditions.
- Core Achievement: Demonstrated AC Optically-Detected Magnetic Resonance (AC-ODMR) using NV ensembles in a DAC up to 6 GPa.
- Application Potential: Enables high-resolution magnetic resonance spectroscopy of extremely small sample volumes (0.1-1 nL) at pressures previously inaccessible to conventional NMR.
- Material Requirements: The experiment relied on ultra-pure Type IIac diamond anvils and a small, precisely cut NV diamond crystal (20 ”m thickness) with controlled nitrogen concentration (0.3 ppm).
- Microwave Delivery: Custom-fabricated 8 ”m thick gold microwave strips were required to generate the necessary strong Hâ fields (Rabi frequency Ω > 5 MHz) within the confined sample space.
- Key Limitation: Sensitivity (η) is currently limited by inhomogeneous broadening due to non-uniform Hâ fields and pressure gradients.
- Future Improvement: The authors suggest utilizing isotopically pure 12C diamond and lower NV concentrations to significantly enhance the decoherence time (T2) and improve sensitivity by orders of magnitude.
- 6CCVD Value Proposition: 6CCVD specializes in providing the custom SCD materials, precise dimensions, tailored NV doping, and advanced metalization required to replicate and extend this high-pressure quantum sensing research.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper detailing the experimental parameters and results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Pressure Achieved | 5.96 | GPa | AC sensing demonstrated via echo sequences. |
| SCD Crystal Dimensions | ~100 x 75 x 20 | ”m | Dimensions of the NV sensing diamond. |
| NV Concentration | 0.3 | ppm | Nitrogen concentration in the sensing diamond. |
| Diamond Anvil Type | IIac | N/A | Used to minimize background fluorescence. |
| External Magnetic Field (H0) | 29 | mT | Applied field magnitude. |
| Required Rabi Frequency (Ω) | > 5 | MHz | Necessary for efficient 90° pulses (50 ns duration). |
| Gold Antenna Thickness | 8 | ”m | Thickness of the electroplated microwave strips. |
| Zero-Field Splitting (D) at 0 GPa | 2866 | MHz | Resonance frequency of the NV transition. |
| Pressure Dependence of D | 11.72 | MHz/GPa | Used to measure pressure via resonance shift. |
| Ambient Sensitivity (η) | 1.9 | nT/âHz | Measured sensitivity of the AC-ODMR setup. |
| Decoherence Time (T2) | ~ 200 | ”s | Limits the minimum detectable frequency (~10 kHz). |
| Linewidth Broadening Factor | 8 | N/A | Factor increase in linewidth observed under pressure (0 GPa to 5.96 GPa). |
Key Methodologies
Section titled âKey MethodologiesâThe experiment required specialized material preparation and integration techniques to enable ODMR within the high-pressure DAC environment:
- SCD Crystal Preparation: A small NV diamond crystal (0.3 ppm NVs) was cut and polished to a precise 20 ”m thickness and secured to the anvil culet, aligning the [100] axis parallel to the DAC axis.
- Anvil Selection: Type IIac diamond anvils were selected for their low nitrogen impurity levels to minimize background fluorescence and maximize optical contrast.
- Gasket Fabrication: Copper-beryllium gaskets (0.3 mm thick) were pre-indented and drilled (260 ”m sample hole) via electrical discharge machining (EDM).
- Microwave Antenna Fabrication: 8 ”m thick gold microwave strips were created via electroplating onto a substrate, chemically liberated, and then transferred onto the anvil culet using tweezers and adhesive.
- Insulation: The gold antenna was electrically insulated from the conducting gasket using a thin layer of epoxy mixed with aluminum oxide and/or boron nitride powders, cured under compression.
- Optical Detection: A long-working distance objective (N.A. 0.40) was used to focus the 532 nm excitation laser and collect fluorescence through the transparent diamond anvils.
- AC Sensing Protocol: Dynamical decoupling sequences (e.g., Ramsey, XY8-16) were implemented using microwave pulse sequences generated by an arbitrary waveform generator (AWG) to detect time-varying magnetic fields (AC-ODMR).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials and custom fabrication services necessary to replicate and significantly advance this high-pressure quantum sensing research. Our capabilities directly address the material purity, dimensional precision, and metalization requirements identified in the paper.
| Research Requirement | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| Ultra-Pure Diamond Anvils (Type IIac) | Optical Grade Single Crystal Diamond (SCD) | We provide high-purity SCD wafers up to 125mm, ensuring extremely low nitrogen content for minimal background fluorescence and maximum ODMR signal contrast (ÎI). |
| Isotopically Pure 12C Diamond | High-Purity Isotopic SCD Substrates | Utilizing isotopically enriched 12C diamond is critical for suppressing nuclear spin bath noise, significantly enhancing the NV center decoherence time (T2 >> 200 ”s), and achieving the required pT/âHz sensitivity. |
| Precise SCD Crystal Dimensions (20 ”m thickness) | Custom Dimensions and Thickness Control | 6CCVD offers SCD plates cut and polished to custom dimensions, supporting thicknesses from 0.1 ”m up to 500 ”m, ensuring perfect fit and alignment within the DAC geometry. |
| High-Quality Surface Finish | Precision Polishing (Ra < 1 nm) | Our SCD material is polished to an industry-leading roughness (Ra < 1 nm), minimizing optical scattering and maximizing the efficiency of excitation and fluorescence collection through the anvils. |
| Custom Gold Microwave Antenna (8 ”m thick) | Advanced Metalization Services (Au, Ti, Pt) | We offer internal metalization capabilities, including deposition and patterning of Au, Ti, Pt, Pd, W, and Cu. We can fabricate custom antenna designs (e.g., straight strips or circular loops) directly onto the SCD culet surfaces, ensuring optimal Hâ field homogeneity and stability under pressure. |
| Need for Homogeneous Hâ Field | Engineering Consultation & Design Support | 6CCVDâs in-house PhD team provides expert material selection and engineering support to optimize diamond properties (e.g., NV placement, isotopic purity) for high-pressure AC-ODMR projects, mitigating issues like inhomogeneous broadening. |
For custom specifications or material consultation regarding high-pressure quantum sensing or ODMR applications, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Nitrogen-vacancy color centers in diamond have attracted broad attention as\nquantum sensors for both static and dynamic magnetic, electrical, strain and\nthermal fields, and are particularly attractive for quantum sensing under\npressure in diamond anvil cells. Optically-based nuclear magnetic resonance may\nbe possible at pressures greater than a few GPa, and offers an attractive\nalternative to conventional Faraday-induction based detection. Here we present\nAC sensing results and demonstrate synchronized readout up to 6 GPa, but find\nthat the sensitivity is reduced due to inhomogeneities of the microwave field\nand pressure within the sample space. These experiments enable the possibility\nfor all-optical high resolution magnetic resonance of nanoliter sample volumes\nat high pressures.\n
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 1996 - High Pressure Experimental Methods [Crossref]