Coherent microwave control of a nuclear spin ensemble at room temperature
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-04-15 |
| Journal | Physical review. B./Physical review. B |
| Authors | Paul Huillery, J. Leibold, Tom Delord, Nicolas Loménie, Jocelyn Achard |
| Institutions | Université Paris Sciences et Lettres, Sorbonne Université |
| Citations | 16 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Coherent Microwave Control of Nuclear Spin Ensembles
Section titled âTechnical Documentation & Analysis: Coherent Microwave Control of Nuclear Spin EnsemblesâExecutive Summary
Section titled âExecutive SummaryâThis research demonstrates a significant advancement in solid-state quantum technology by achieving coherent microwave control and polarization of $^{14}$N nuclear spin ensembles within Nitrogen-Vacancy (NV) centers in diamond at room temperature.
- Core Achievement: Coherent manipulation of nuclear spin ensembles via nominally forbidden Electron-Nuclear Spin Transitions (ENST) using off-axis magnetic fields (B $\approx 0.01$ T) in the microwave regime.
- Material Requirement: The success relies critically on high-quality, $^{12}$C enriched bulk diamond grown by Chemical Vapor Deposition (CVD) with extremely low, controlled NV center concentration ($\approx 0.3$ ppb).
- Key Techniques: Demonstrated fast Rabi oscillations ($\Omega_{a+} \approx 147$ kHz), Coherent Population Trapping (CPT) with narrow linewidths ($8.2$ kHz), and a new method for nuclear spin ensemble polarization ($\approx 60$%).
- Methodology: Utilized Optically Detected Magnetic Resonance (ODMR) and a confocal microscope setup, requiring precise control over microwave fields and optical excitation (532 nm laser).
- Future Applications: The technique provides a scalable platform for long-lived quantum memory (microwave photon storage via EIT) and transduction applications, particularly in spin-mechanics (resolved sideband cooling).
- 6CCVD Value Proposition: 6CCVD specializes in providing the necessary high-ppurity, low-strain Single Crystal Diamond (SCD) substrates with precise control over nitrogen doping required to replicate and scale this ensemble quantum research.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results, focusing on the physical parameters and achieved performance metrics.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Type | $^{12}$C enriched bulk CVD | N/A | Used for high quality and low strain. |
| NV Center Concentration | $\approx 0.3$ | ppb | Low concentration achieved via N$_{2}$ injection during growth. |
| Magnetic Field (B) Range | $57$ to $82.71$ | G | Modest, off-axis magnetic field amplitude. |
| Magnetic Field Angle ($\theta$) | $10.2$ to $87.9$ | ° | Angle relative to the NV axis (off-axis configuration). |
| ODMR Frequency | $\approx 2.9$ | GHz | Microwave frequency used for spin driving. |
| Rabi Frequency ($\Omega_{a+}$) | $2\pi \times 147(1)$ | kHz | Coherent driving rate for nuclear spin exchanging transition. |
| Rabi Damping Time ($T_R$) | $22(4)$ | ”s | Measured on the nuclear spin exchanging transition. |
| CPT Peak Width (FWHM) | $2\pi \times 8.2(1.0)$ | kHz | Achieved at electron spin polarization rate $\gamma_{las} = 18(1)$ kHz. |
| Nuclear Spin Polarization | $\approx 60$ | % | Achieved selectively across all three nuclear spin states. |
| Optical Excitation | $532$ | nm | Green laser used for electron spin polarization. |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relies on precise material engineering and sophisticated microwave/optical control techniques.
- Material Growth: High-quality, $^{12}$C enriched bulk diamond was grown via Chemical Vapor Deposition (CVD). Nitrogen (N$_{2}$) was injected during the growth process to achieve a very low, controlled NV center concentration ($\approx 0.3$ ppb).
- Experimental Setup: A confocal microscope was used to perform Optically Detected Magnetic Resonance (ODMR) measurements on an ensemble of hundreds of NV centers.
- Magnetic Field Application: A permanent magnet was placed near the sample to apply a uniform, off-axis DC magnetic field (B $\approx 0.01$ T) at a specific angle ($\theta$) relative to the NV axis.
- Microwave Control: A single-loop antenna delivered the microwave field (around $2.9$ GHz) to drive the electron-nuclear spin exchanging transitions (ENST).
- Spin Polarization & Readout: A $532$ nm laser was used for optical electron spin polarization and subsequent photoluminescence (PL) readout. Pulse sequences (e.g., preparation, pump, read-out) were controlled by a PulseBlaster card for synchronization.
- Coherent Manipulation: Measurements included fast Rabi oscillations, and the isolation of three-level $\Lambda$-schemes to achieve Coherent Population Trapping (CPT) of the nuclear spin ensemble at room temperature.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the advanced diamond materials and customization services required to replicate and extend this groundbreaking research in quantum information storage and spin-mechanics.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the low strain, high purity, and controlled NV density demonstrated in this paper, researchers require Optical Grade Single Crystal Diamond (SCD).
| 6CCVD Material | Key Specification Match | Customization Potential |
|---|---|---|
| Optical Grade SCD | High purity, low strain, essential for long coherence times ($T_{2}$). | We offer SCD plates up to $500$ ”m thick and substrates up to $10$ mm thick. |
| Controlled N Doping | Precise control over NV concentration ($\approx 0.3$ ppb required). | 6CCVD controls nitrogen incorporation during MPCVD growth to tune NV density for ensemble or single-spin applications. |
| $^{12}$C Enrichment | Required for maximizing nuclear spin coherence time. | We supply high-purity $^{12}$C enriched diamond substrates upon request. |
Customization Potential
Section titled âCustomization PotentialâThe experimental setup requires precise microwave delivery and high-quality surface preparation, both of which are core 6CCVD capabilities.
| Requirement from Research | 6CCVD Customization Service | Technical Advantage |
|---|---|---|
| Microwave Delivery | Custom metalization (Au, Pt, Ti, W, Cu) services. | We can fabricate on-chip microwave structures (e.g., coplanar waveguides or antennas) directly onto the diamond surface, improving coupling efficiency and field homogeneity compared to external loop antennas. |
| Substrate Dimensions | Custom dimensions and thickness. | Plates/wafers available up to $125$ mm (PCD) and custom SCD substrates up to $10$ mm thick, enabling large-scale ensemble experiments. |
| Surface Quality | Ultra-low roughness polishing. | SCD polishing to Ra < $1$ nm ensures minimal surface defects that could degrade NV center performance or introduce strain. |
Engineering Support
Section titled âEngineering SupportâThe successful implementation of Coherent Population Trapping (CPT) and nuclear spin polarization relies on complex Hamiltonian analysis and precise material selection.
- Material Selection for Quantum Applications: 6CCVDâs in-house PhD team specializes in the physics of NV centers and can assist researchers in selecting the optimal diamond specifications (e.g., NV density, isotopic purity, and surface termination) for similar Quantum Memory and Spin-Mechanics Transduction projects.
- Global Logistics: We ensure reliable global shipping (DDU default, DDP available) for time-sensitive research projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We use nominally forbidden electron-nuclear spin transitions in\nnitrogen-vacancy (NV) centers in diamond to demonstrate coherent manipulation\nof a nuclear spin ensemble using microwave fields at room temperature. We show\nthat employing an off-axis magnetic field with a modest amplitude($\approx$\n0.01 T) at an angle with respect to the NV natural quantization axes is enough\nto tilt the direction of the electronic spins, and enable efficient spin\nexchange with the nitrogen nuclei of the NV center. We could then demonstrate\nfast Rabi oscillations on electron-nuclear spin exchanging transitions,\ncoherent population trapping and polarization of nuclear spin ensembles in the\nmicrowave regime. Coupling many electronic spins of NV centers to their\nintrinsic nuclei offers full scalability with respect to the number of\ncontrollable spins and provides prospects for transduction. In particular, the\ntechnique could be applied to long-lived storage of microwave photons and to\nthe coupling of nuclear spins to mechanical oscillators in the resolved\nsideband regime.\n