Double quantum magnetometry at large static magnetic fields
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-03-11 |
| Journal | Physical review. B./Physical review. B |
| Authors | Carlos Munuera-Javaloy, Ăñigo Arrazola, E. Solano, J. Casanova |
| Institutions | Ikerbasque, University of the Basque Country |
| Citations | 7 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Double Quantum Magnetometry in Diamond
Section titled âTechnical Documentation & Analysis: Double Quantum Magnetometry in DiamondâThis document analyzes the requirements and achievements of the research paper, âDouble Quantum Magnetometry at Large Static Magnetic Fields,â and maps them directly to the advanced material and fabrication capabilities offered by 6CCVD (6ccvd.com), an expert supplier of MPCVD diamond for quantum technologies.
Executive Summary
Section titled âExecutive SummaryâThe research successfully demonstrates a robust protocol for Double Quantum Magnetometry (DQM) using Nitrogen Vacancy (NV) centers in diamond, specifically targeting enhanced nanoscale Nuclear Magnetic Resonance (NMR) capabilities.
- Application Focus: High-sensitivity nanoscale NMR, leveraging the enhanced chemical shift detection available in the large static magnetic field regime ($B_z \approx 3$ T).
- Core Achievement: The DQM protocol, utilizing tailored, two-tone stroboscopic Microwave (MW) radiation, achieves enhanced sensor-signal interaction while operating at moderate MW power.
- Critical Advantage: The method intrinsically eliminates inhomogeneous broadening in the measured spectrum, a significant limitation found in conventional Single Quantum Magnetometry (SQM) protocols.
- Material Requirement: Success relies on high-quality diamond substrates capable of hosting NV centers with long quantum coherence times (milliseconds) at room temperature.
- Robustness: The tailored pulse sequences are demonstrated to be highly robust against realistic experimental imperfections, including 1% MW field errors and NV spin transition energy shifts up to $(2\pi) \times 20$ kHz.
- General Applicability: The protocol is general and applicable to other solid-state quantum sensors, such as Silicon Vacancy (SiV) centers, requiring high-purity CVD diamond.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper, highlighting the demanding operational parameters of the DQM protocol:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Static Magnetic Field (Bz) | 3 | T | Simulation condition for large field regime |
| NV Zero Field Splitting (D) | $2.87$ | GHz | Fundamental NV property |
| NV Gyromagnetic Ratio ($\gamma_e$) | $28.024$ | GHz/T | Fundamental NV property |
| H Larmor Frequency ($\omega_L$) | $\approx 127$ | MHz | At $B_z = 3$ T |
| Tailored Rabi Frequency ($\Omega_{max}$) | $\approx 40$ | MHz | Maximum value for realistic finite-width DQM pulses |
| Tailored Pulse Time ($t_\pi$) | $\approx 0.16$ | ”s | Duration of extended, tailored $\Omega(t)$ pulses |
| Top-Hat Pulse Time ($t_\pi$) | $\approx 7$ | ns | Duration for instantaneous pulse approximation |
| MW Field Error Tolerance | 1 | % | Robustness test parameter |
| NV Spin Transition Energy Shift | $(2\pi) \times 20$ | kHz | Robustness test parameter |
| Target Nuclei Distance | $\approx 3.1$ | nm | Average distance from NV sensor (5-H cluster) |
Key Methodologies
Section titled âKey MethodologiesâThe DQM protocol relies on precise control over the NV spin state using tailored microwave fields within a stroboscopic dynamical decoupling framework.
- Quantum Sensor Initialization: NV centers in diamond are initialized and measured using laser fields, and controlled using Microwave (MW) radiation, leveraging their long room-temperature coherence times.
- Rotating Frame Transformation: The NV Hamiltonian is analyzed in a rotating frame with respect to the zero-field splitting ($D S_z^2$) and the static magnetic field interaction ($|\gamma_e| B_z S_z$).
- Three-Pulse Sequences: DQM is achieved by inducing rotations between the $|1\rangle$ and $|-1\rangle$ states using specific three-pulse sequences (e.g., $\text{U}^{[+1,-1,+1]}{[\pi,0]}$ and $\text{U}^{[-1,+1,-1]}{[\pi,\pi/2]}$) which act as an effective pulse on the $S_z$ operator.
- Tailored Rabi Frequency $\Omega(t)$: To overcome the severe signal reduction associated with finite-width top-hat pulses in the large $B_z$ regime, a tailored Rabi frequency $\Omega(t)$ is introduced. This modulation function is designed to cancel integrals involving $\pi$ pulses, ensuring the performance matches that of ideal instantaneous pulses.
- Stroboscopic Dynamical Decoupling (DD): The protocol utilizes stroboscopic DD radiation patterns (similar to the XY family) to remove noisy contributions and control errors, enhancing the robustness of the measurement.
- Resonance Condition: The experiment relies on matching the Larmor frequency ($\omega_L$) of the target nuclei (e.g., H) with an integer harmonic ($l$) of the sequence repetition frequency ($l \omega_p = \omega_L$).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful implementation of high-field DQM for nanoscale NMR requires diamond materials with exceptional purity, low strain, and precise surface engineering. 6CCVD is uniquely positioned to supply the necessary substrates and customization services to replicate and advance this research.
Applicable Materials for Quantum Sensing
Section titled âApplicable Materials for Quantum Sensingâ| Research Requirement | 6CCVD Material Solution | Key Specification Match |
|---|---|---|
| High Coherence/Purity | Optical Grade Single Crystal Diamond (SCD) | Ultra-low nitrogen concentration (< 1 ppb) to minimize decoherence and maximize NV center performance. |
| Strain Management | Low-Strain SCD Substrates | Essential for maintaining the spectral stability of NV centers, especially critical for high-resolution NMR. |
| Scalability/Integration | Polycrystalline Diamond (PCD) Wafers | Custom dimensions up to 125mm for scaling integrated quantum devices and large-area sensor arrays. |
| Alternative Sensors | Boron-Doped Diamond (BDD) | Available for electrochemical or alternative quantum sensing applications (e.g., if BDD is used for integrated circuitry). |
Customization Potential & Fabrication Services
Section titled âCustomization Potential & Fabrication ServicesâThe DQM protocol requires precise MW control, often implemented via on-chip waveguides or antennas. 6CCVD offers comprehensive fabrication services critical for integrating the diamond sensor into the quantum device architecture.
| Research Requirement | 6CCVD Customization Service | Technical Advantage |
|---|---|---|
| MW Control Integration | Custom Metalization Services | Deposition of Au, Pt, Pd, Ti, W, or Cu layers for creating high-frequency MW transmission lines directly on the diamond surface. |
| Surface Quality | Ultra-Precision Polishing | SCD surfaces polished to $\text{Ra} < 1$ nm, minimizing surface noise and maximizing the proximity of external target samples for nanoscale NMR. |
| Geometry & Device Shaping | Custom Dimensions & Laser Cutting | Plates and wafers available in custom sizes (SCD up to 10mm thickness, PCD up to 125mm diameter). Precision laser cutting for complex geometries required for specific MW antenna designs. |
| Thickness Control | Precision SCD/PCD Thickness | SCD layers available from $0.1$ ”m to $500$ ”m, allowing researchers to optimize the depth of NV implantation or the thickness of the bulk substrate. |
Engineering Support
Section titled âEngineering SupportâThe complexity of tailoring Rabi frequencies and implementing stroboscopic DD sequences requires deep material and quantum physics expertise.
6CCVDâs in-house PhD team specializes in the material science of MPCVD diamond for quantum applications. We can assist researchers and engineers with:
- Material Selection: Optimizing diamond grade (purity, strain, crystal orientation) to ensure maximum NV coherence time required for high-fidelity DQM experiments.
- NV Creation Strategy: Consulting on optimal implantation or in-situ growth techniques to achieve the desired NV density and depth profile for nanoscale NMR projects.
- Interface Design: Providing technical specifications for metalization layers necessary for high-power, high-frequency MW delivery systems used in tailored pulse sequences.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We present a protocol to achieve double quantum magnetometry at large static magnetic fields. This is a regime where sensitive sample parameters, such as the chemical shift, get enhanced facilitating their characterization. In particular, our method delivers two-tone stroboscopic radiation patterns with modulated Rabi frequencies to achieve larger spectral signals. Furthermore, it does not introduce inhomogeneous broadening in the sample spectrum preventing signal misinterpretation. Moreover, our protocol is designed to work under realistic conditions such as the presence of moderate microwave power and errors on the radiation fields. Albeit we particularise to nitrogen vacancy centers, our protocol is general, thus applicable to distinct quantum sensors.