Measurement of the excited-state transverse hyperfine coupling in NV centers via dynamic nuclear polarization
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2016-12-14 |
| Journal | DSpace@MIT (Massachusetts Institute of Technology) |
| Authors | Francesco Poggiali, Nicole Fabbri, Paola Cappellaro |
| Citations | 3 |
| Analysis | Full AI Review Included |
Technical Analysis and Documentation: NV Center Quantum Sensing Platforms
Section titled âTechnical Analysis and Documentation: NV Center Quantum Sensing PlatformsâThis documentation analyzes the methods and requirements detailed in âMeasurement of the excited-state transverse hyperfine coupling in NV centers via dynamic nuclear polarizationâ (Poggiali et al., 2017) and connects them directly to the advanced MPCVD diamond solutions available through 6CCVD.
Executive Summary
Section titled âExecutive SummaryâThe research successfully characterized a critical parameter for Nitrogen-Vacancy (NV) center quantum control, directly enabling enhanced initialization and operation of nuclear spin qubits.
- Core Achievement: First direct experimental measurement of the excited-state transverse hyperfine coupling ($C_{\perp}$) between the NV electronic spin and the substitutional 14N nuclear spin.
- Resulting Parameter: $C_{\perp}$ was precisely determined as $(-23 \pm 3)$ MHz, significantly deviating from prior theoretical assumptions of isotropic coupling.
- Methodological Breakthrough: The determination relies on precisely monitoring the transient behavior of Dynamic Nuclear Polarization (DNP) near the Excited State Level Anti-Crossing (ESLAC).
- Material Requirement: The experiment necessitated extremely high-purity, low-strain Electronic Grade Single Crystal Diamond (SCD) with minimal nitrogen background (< 5 ppb 14N) to isolate single NV centers.
- Application Relevance: Accurate knowledge of $C_{\perp}$ is vital for optimizing protocols requiring fast and highly accurate control of nuclear spins, accelerating progress in quantum computing, enhanced NMR, and quantum sensing applications.
- 6CCVD Value Proposition: 6CCVD provides the necessary Electronic Grade SCD substrates, offering unmatched purity control, custom crystal orientation, and specialized processing (metalization, polishing) required for scaling similar quantum hardware.
Technical Specifications
Section titled âTechnical SpecificationsâThe following critical parameters and hard data points were extracted from the study detailing the NV spin system and experimental conditions.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Measured Transverse Coupling (C⊥) | -23 $\pm$ 3 | MHz | Excited-state 14N hyperfine coupling |
| Ground State Zero-Field Splitting (Dg) | 2.87 | GHz | Used for Hamiltonian model |
| Excited State Zero-Field Splitting (De) | 1.42 | GHz | Used for Hamiltonian model |
| Nuclear Quadrupole Interaction (Q) | -4.945 | MHz | 14N nucleus |
| ESLAC Magnetic Field (B) | $\approx 510$ | G | Location of Excited State Level Anti-Crossing |
| Operating Magnetic Field Range | 200 to 420 | G | Applied external field B |
| NV Center Nitrogen Concentration (14N) | < 5 | ppb | Required for electronic grade bulk diamond |
| Optical Excitation Wavelength | 532 | nm | Spin polarization laser |
| Ramsey MW Pulse Duration | 25 - 50 | ns | Used to drive electronic spin transitions |
| DNP Characteristic Time Constant ($\tau$) | 1 to 5 | $\mu$s | Time scale of nuclear polarization process |
Key Methodologies
Section titled âKey MethodologiesâThe determination of the excited-state transverse hyperfine coupling relies on controlling the NV centerâs environment and utilizing highly precise spin manipulation sequences, necessitating robust material properties.
- High-Purity Material Sourcing: Experiments were performed on electronic grade bulk diamond with natural 1.1% 13C abundance and extremely low nitrogen concentration (< 5 ppb) to ensure the isolation of single NV centers free from proximal spin noise.
- Spin Initialization: The NV electronic spin (S=1) was polarized to the ms = 0 ground state sublevel via continuous 532 nm optical pumping (Green Laser).
- Dynamic Nuclear Polarization (DNP) Induction: The system was subjected to optical pumping for variable durations (0.5 $\mu$s to 17.5 $\mu$s) while precisely tuned to magnetic fields (200 G to 420 G) near the ESLAC ($\approx 510$ G).
- Spin Control and Readout: Ramsey spectroscopy involving microwave ($\pi$/2 pulses) and radiofrequency ($\pi$ pulses) driving was used to coherently manipulate the electronic and 14N nuclear spins.
- Hyperfine Population Measurement: Fourier analysis of the Ramsey signal components yielded the relative probability (PmI) of the three 14N nuclear spin projections ($m_{I} = 0, \pm 1$).
- Data Modeling: The time evolution of $P_{+1}$ was compared against a numerical simulation derived from the generalized Liouville master equation to extract the unknown transverse coupling $C_{\perp}$ as the only adjustable parameter.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is an expert provider of MPCVD diamond necessary to replicate, optimize, and scale this advanced quantum research. Our ability to control material purity, crystal dimensions, and surface functionalization directly addresses the stringent requirements of NV center platforms.
Applicable Materials
Section titled âApplicable MaterialsâThe precise measurement of the excited-state Hamiltonian requires high-purity, low-strain diamond with controlled defect density.
| Research Requirement | 6CCVD Material Solution | Technical Advantage |
|---|---|---|
| Isolation of Single NVs | Electronic Grade Single Crystal Diamond (SCD) | Ultra-low [N] concentration (< 1 ppb unintentional, down to 5 ppb intentional) for high-fidelity qubits. |
| High Resolution DNP | Isotopically Pure SCD (12C) | Reduces background spin noise from 13C (natural abundance is 1.1%), leading to significantly enhanced T2 coherence times and improved spectral resolution. |
| Potential for Scaling | Optical Grade Polycrystalline Diamond (PCD) | Available in large area wafers (up to 125mm) for high-throughput screening and integration into commercial devices. |
| Bulk Integration | Custom Substrate Thicknesses | SCD plates available up to 500 $\mu$m thick, allowing deep-bulk NV implantation or controlled surface NV generation. |
Customization Potential
Section titled âCustomization PotentialâThe integration of NV quantum platforms often demands specialized physical and electrical interfaces. 6CCVD supports the full transition from fundamental research to integrated devices.
- Precision Polishing: To enable high-fidelity optical addressing via confocal microscopy, 6CCVD guarantees ultra-smooth surfaces, providing Ra < 1 nm on SCD wafers and Ra < 5 nm on inch-sized PCD wafers.
- Custom Metalization Schemes: The experimental setup utilized a wire antenna for MW/RF delivery. For on-chip integration, 6CCVD offers internal capabilities for depositing custom metal films (Au, Pt, Pd, Ti, W, Cu) for lithographically defined microwave guides (CPWs) and electrodes.
- Custom Dimensions and Orientation: SCD wafers can be supplied in custom dimensions and specific crystallographic orientations (e.g., [111] required for magnetic field alignment) tailored to bespoke quantum experiments.
Engineering Support
Section titled âEngineering SupportâThis research demonstrates the necessity of high-precision materials engineering to extract fundamental physics data.
- Material Selection Expertise: 6CCVDâs in-house PhD team provides consultative support for engineers and scientists. We specialize in assisting with NV center material design, ensuring optimal [N] concentration, isotopic purity, and substrate characteristics needed for similar Dynamic Nuclear Polarization (DNP) or Quantum Sensing projects.
- Global Logistics: We ensure reliable global supply chain management with flexible shipping options (DDU default, DDP available) to deliver high-value diamond materials worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Precise knowledge of a quantum systemâs Hamiltonian is a critical pre-requisite for its use in many quantum information technologies. Here, we report a method for the precise characterization of the non-secular part of the excited-state Hamiltonian of an electronic-nuclear spin system in diamond. The method relies on the investigation of the dynamic nuclear polarization mediated by the electronic spin, which is currently exploited as a primary tool for initializing nuclear qubits and performing enhanced nuclear magnetic resonance. By measuring the temporal evolution of the population of the ground-state hyperfine levels of a nitrogen-vacancy center, we obtain the first direct estimation of the excited-state transverse hyperfine coupling between its electronic and nitrogen nuclear spin. Our method could also be applied to other electron-nuclear spin systems, such as those related to defects in silicon carbide.