High-sensitivity spin-based electrometry with an ensemble of nitrogen-vacancy centers in diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-05-26 |
| Journal | Physical review. A/Physical review, A |
| Authors | Edward H. Chen, Hannah Clevenson, Kerry A. Johnson, Linh Pham, Dirk Englund |
| Institutions | Texas A&M University, MIT Lincoln Laboratory |
| Citations | 80 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Spin-Based Electrometry in MPCVD Diamond
Section titled âTechnical Documentation & Analysis: Spin-Based Electrometry in MPCVD DiamondâExecutive Summary
Section titled âExecutive SummaryâThis research demonstrates a robust, high-sensitivity, spin-based electrometer utilizing an ensemble of Nitrogen-Vacancy (NV-) centers in Chemical Vapor Deposition (CVD) diamond. The findings validate diamond as a leading platform for miniaturized, ambient-condition electric field sensing.
- Core Achievement: Demonstrated shot-noise limited electric field sensitivity approaching 1 V/cm/âHz under ambient conditions (0.05-10 Hz).
- Methodology: Utilized the Stark effect on the NV- degenerate triplet states, combined with symmetric detection to achieve first-order immunity to temperature fluctuations.
- Material Used: A 3.0 x 3.0 x 0.32 mm3 CVD diamond plate with a low NV- density (~1 ppb) was used, featuring evaporated Gold (Au) electrodes.
- Noise Mitigation: The technique successfully deconvolved temperature fluctuations (2.4 ± 1.2 mK/âHz) from electric field fluctuations (1.6 ± 1.2 V/cm/âHz), resulting in an 8x improvement in sensitivity over non-deconvolved measurements.
- Future Potential: The authors project a shot-noise limited sensitivity of 6 x 10-3 V/cm/âHz by utilizing diamond with 1000x higher NV- densities and improved photon collection efficiency.
- 6CCVD Relevance: This work confirms the critical need for high-quality, low-strain, custom-dimensioned MPCVD diamond substrates with precisely controlled NV doping and integrated metalization, all of which are core 6CCVD capabilities.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Dimensions | 3.0 x 3.0 x 0.32 | mm3 | CVD grown plate, (100) orientation faces |
| NV- Density (Experimental) | ~1 | ppb | Low density, produced during CVD growth |
| Achieved Sensitivity (Ambient) | ~1 | V/cm/âHz | Shot-noise limited, low frequency (0.05-10 Hz) |
| Projected Sensitivity (High Density) | 6 x 10-3 | V/cm/âHz | Requires 1000x higher NV density |
| Operating Frequency Range | 0.05 - 10 | Hz | Extremely low frequency regime |
| Laser Excitation Power (CW) | 1.8 | W | Used for maximum sensitivity |
| Laser Power Density (Incident) | ~30 | ”W/”m2 | High power density contributed to temperature noise |
| Bias Voltage (High Stability) | 225 | Volts | Used for ODMR measurements |
| Transverse Electric Susceptibility (kâ„) | 7.0 ± 1.1 | Hz/(V/cm) | Measured ensemble average at 225V bias |
| Ground State Crystal Field Splitting (D) | 2.8 | GHz | NV- ground state parameter |
| Excited State Crystal Field Splitting (D) | 1.4 | GHz | NV- excited state parameter |
| Temperature Fluctuation Noise Floor | 2.4 ± 1.2 | mK/âHz | Measured via correlated ODMR sum channel |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relied on precise material engineering and advanced optical/microwave control techniques:
- Substrate Preparation: A CVD diamond plate (3.0 x 3.0 x 0.32 mm3) with (100) crystallographic orientation was selected to ensure the applied electric field produced an equal projection onto all eight NV orientations.
- Electrode Deposition: Gold (Au) electrodes were evaporated onto the two square faces of the diamond plate to enable the application of the external electric field.
- Excitation and MW Delivery: A collimated CW laser beam (~200 ”m diameter) was used for excitation. Microwave (MW) excitation was delivered to the NV ensemble via an âΩâ shaped stripline patterned on a printed circuit board.
- Magnetic Field Zeroing: A gradient descent method was employed to zero the magnetic field (B = 0), maximizing the ODMR contrast and achieving optimal electric field sensitivity.
- ODMR Measurement: Optically Detected Magnetic Resonance (ODMR) was measured using continuous-wave laser and MW excitation.
- Noise Deconvolution: Temperature and electric field fluctuations were separated by monitoring two electric and strain sensitive transitions (mI = ±0). The sum of the time traces corresponded to temperature fluctuations (D parameter shift), while the difference corresponded to electric field fluctuations (Stark shift).
- Lock-In Amplification: An FPGA-based high-speed DAC system performed both waveform generation and lock-in detection to read out the optical signals, enabling measurement at extremely low frequencies (0.05 Hz).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the need for specialized diamond materials and fabrication services to push NV electrometry sensitivity into the 10-3 V/cm/âHz regime. 6CCVD is uniquely positioned to supply the required custom substrates and integrated services.
| Requirement from Paper/Projection | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| Low-Strain Substrate for Coherence | Optical Grade Single Crystal Diamond (SCD) | SCD offers superior crystalline quality and low intrinsic strain, essential for maximizing the inhomogeneous NV- coherence time (T2*) and achieving shot-noise limited detection. We guarantee Ra < 1 nm polishing for optimal optical coupling. |
| High NV Ensemble Density | Custom Nitrogen Doping (PCD/SCD) | To achieve the projected 6 x 10-3 V/cm/âHz sensitivity (requiring 1000x higher NV density), 6CCVD provides precise control over nitrogen incorporation during MPCVD growth to optimize NV concentration. |
| Custom Device Dimensions | Custom Plates/Wafers up to 125 mm | The experiment used a 3.0 x 3.0 x 0.32 mm3 plate. 6CCVD specializes in custom laser cutting and precise thickness control (0.1 ”m to 10 mm substrates) to meet exact micro-device integration requirements. |
| Integrated Electrode Fabrication | Internal Metalization Services | The device required evaporated Gold (Au) electrodes. 6CCVD offers in-house deposition of standard stacks (e.g., Ti/Pt/Au, Ti/W/Au) optimized for adhesion and low-resistance contacts on diamond surfaces, streamlining device fabrication. |
| Surface Quality for Optical Readout | Ultra-Precision Polishing (Ra < 1 nm) | High-quality polishing minimizes scattering losses and ensures uniform electrode adhesion, critical for high-efficiency photon collection (I) and maximizing ODMR contrast (C). |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team provides expert consultation on material selection and optimization for advanced quantum sensing applications. We can assist researchers in defining the optimal balance between NV density, strain management, and surface preparation necessary to replicate or extend this high-sensitivity NV electrometry project.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We demonstrate a spin-based, all-dielectric electrometer based on an ensemble\nof nitrogen-vacancy (NV$^-$) defects in diamond. An applied electric field\ncauses energy level shifts symmetrically away from the NV$^-$âs degenerate\ntriplet states via the Stark effect; this symmetry provides immunity to\ntemperature fluctuations allowing for shot-noise-limited detection. Using an\nensemble of NV$^-$s, we demonstrate shot-noise limited sensitivities\napproaching 1 V/cm/$\sqrt{\text{Hz}}$ under ambient conditions, at low\nfrequencies ($<$10 Hz), and over a large dynamic range (20 dB). A theoretical\nmodel for the ensemble of NV$^-$s fits well with measurements of the\nground-state electric susceptibility parameter, $\langle k_\perp\rangle$.\nImplications of spin-based, dielectric sensors for micron-scale electric-field\nsensing are discussed.\n